openadk/target/linux/patches/2.6.31.4/aufs2.patch

diff -Nur linux-2.6.31.4.orig/Documentation/ABI/testing/debugfs-aufs linux-2.6.31.4/Documentation/ABI/testing/debugfs-aufs
--- linux-2.6.31.4.orig/Documentation/ABI/testing/debugfs-aufs	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/Documentation/ABI/testing/debugfs-aufs	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,40 @@
+What:		/debug/aufs/si_<id>/
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05@yahoo.co.jp>
+Description:
+		Under /debug/aufs, a directory named si_<id> is created
+		per aufs mount, where <id> is a unique id generated
+		internally.
+
+What:		/debug/aufs/si_<id>/xib
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05@yahoo.co.jp>
+Description:
+		It shows the consumed blocks by xib (External Inode Number
+		Bitmap), its block size and file size.
+		When the aufs mount option 'noxino' is specified, it
+		will be empty. About XINO files, see
+		Documentation/filesystems/aufs/aufs.5 in detail.
+
+What:		/debug/aufs/si_<id>/xino0, xino1 ... xinoN
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05@yahoo.co.jp>
+Description:
+		It shows the consumed blocks by xino (External Inode Number
+		Translation Table), its link count, block size and file
+		size.
+		When the aufs mount option 'noxino' is specified, it
+		will be empty. About XINO files, see
+		Documentation/filesystems/aufs/aufs.5 in detail.
+
+What:		/debug/aufs/si_<id>/xigen
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05@yahoo.co.jp>
+Description:
+		It shows the consumed blocks by xigen (External Inode
+		Generation Table), its block size and file size.
+		If CONFIG_AUFS_EXPORT is disabled, this entry will not
+		be created.
+		When the aufs mount option 'noxino' is specified, it
+		will be empty. About XINO files, see
+		Documentation/filesystems/aufs/aufs.5 in detail.
diff -Nur linux-2.6.31.4.orig/Documentation/ABI/testing/sysfs-aufs linux-2.6.31.4/Documentation/ABI/testing/sysfs-aufs
--- linux-2.6.31.4.orig/Documentation/ABI/testing/sysfs-aufs	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/Documentation/ABI/testing/sysfs-aufs	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,25 @@
+What:		/sys/fs/aufs/si_<id>/
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05@yahoo.co.jp>
+Description:
+		Under /sys/fs/aufs, a directory named si_<id> is created
+		per aufs mount, where <id> is a unique id generated
+		internally.
+
+What:		/sys/fs/aufs/si_<id>/br0, br1 ... brN
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05@yahoo.co.jp>
+Description:
+		It shows the abolute path of a member directory (which
+		is called branch) in aufs, and its permission.
+
+What:		/sys/fs/aufs/si_<id>/xi_path
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05@yahoo.co.jp>
+Description:
+		It shows the abolute path of XINO (External Inode Number
+		Bitmap, Translation Table and Generation Table) file
+		even if it is the default path.
+		When the aufs mount option 'noxino' is specified, it
+		will be empty. About XINO files, see
+		Documentation/filesystems/aufs/aufs.5 in detail.
diff -Nur linux-2.6.31.4.orig/fs/aufs/aufs.h linux-2.6.31.4/fs/aufs/aufs.h
--- linux-2.6.31.4.orig/fs/aufs/aufs.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/aufs.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * all header files
+ */
+
+#ifndef __AUFS_H__
+#define __AUFS_H__
+
+#ifdef __KERNEL__
+
+#include "debug.h"
+
+#include "branch.h"
+#include "cpup.h"
+#include "dcsub.h"
+#include "dbgaufs.h"
+#include "dentry.h"
+#include "dir.h"
+#include "file.h"
+#include "fstype.h"
+#include "inode.h"
+#include "loop.h"
+#include "module.h"
+#include "opts.h"
+#include "rwsem.h"
+#include "spl.h"
+#include "super.h"
+#include "sysaufs.h"
+#include "vfsub.h"
+#include "whout.h"
+#include "wkq.h"
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/branch.c linux-2.6.31.4/fs/aufs/branch.c
--- linux-2.6.31.4.orig/fs/aufs/branch.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/branch.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,974 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * branch management
+ */
+
+#include <linux/file.h>
+#include "aufs.h"
+
+/*
+ * free a single branch
+ */
+static void au_br_do_free(struct au_branch *br)
+{
+	int i;
+	struct au_wbr *wbr;
+
+	if (br->br_xino.xi_file)
+		fput(br->br_xino.xi_file);
+	mutex_destroy(&br->br_xino.xi_nondir_mtx);
+
+	AuDebugOn(atomic_read(&br->br_count));
+
+	wbr = br->br_wbr;
+	if (wbr) {
+		for (i = 0; i < AuBrWh_Last; i++)
+			dput(wbr->wbr_wh[i]);
+		AuDebugOn(atomic_read(&wbr->wbr_wh_running));
+		AuRwDestroy(&wbr->wbr_wh_rwsem);
+	}
+
+	/* some filesystems acquire extra lock */
+	lockdep_off();
+	mntput(br->br_mnt);
+	lockdep_on();
+
+	kfree(wbr);
+	kfree(br);
+}
+
+/*
+ * frees all branches
+ */
+void au_br_free(struct au_sbinfo *sbinfo)
+{
+	aufs_bindex_t bmax;
+	struct au_branch **br;
+
+	AuRwMustWriteLock(&sbinfo->si_rwsem);
+
+	bmax = sbinfo->si_bend + 1;
+	br = sbinfo->si_branch;
+	while (bmax--)
+		au_br_do_free(*br++);
+}
+
+/*
+ * find the index of a branch which is specified by @br_id.
+ */
+int au_br_index(struct super_block *sb, aufs_bindex_t br_id)
+{
+	aufs_bindex_t bindex, bend;
+
+	bend = au_sbend(sb);
+	for (bindex = 0; bindex <= bend; bindex++)
+		if (au_sbr_id(sb, bindex) == br_id)
+			return bindex;
+	return -1;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * add a branch
+ */
+
+static int test_overlap(struct super_block *sb, struct dentry *h_d1,
+			struct dentry *h_d2)
+{
+	if (unlikely(h_d1 == h_d2))
+		return 1;
+	return !!au_test_subdir(h_d1, h_d2)
+		|| !!au_test_subdir(h_d2, h_d1)
+		|| au_test_loopback_overlap(sb, h_d1, h_d2)
+		|| au_test_loopback_overlap(sb, h_d2, h_d1);
+}
+
+/*
+ * returns a newly allocated branch. @new_nbranch is a number of branches
+ * after adding a branch.
+ */
+static struct au_branch *au_br_alloc(struct super_block *sb, int new_nbranch,
+				     int perm)
+{
+	struct au_branch *add_branch;
+	struct dentry *root;
+
+	root = sb->s_root;
+	add_branch = kmalloc(sizeof(*add_branch), GFP_NOFS);
+	if (unlikely(!add_branch))
+		goto out;
+
+	add_branch->br_wbr = NULL;
+	if (au_br_writable(perm)) {
+		/* may be freed separately at changing the branch permission */
+		add_branch->br_wbr = kmalloc(sizeof(*add_branch->br_wbr),
+					     GFP_NOFS);
+		if (unlikely(!add_branch->br_wbr))
+			goto out_br;
+	}
+
+	if (unlikely(au_sbr_realloc(au_sbi(sb), new_nbranch)
+		     || au_di_realloc(au_di(root), new_nbranch)
+		     || au_ii_realloc(au_ii(root->d_inode), new_nbranch)))
+		goto out_wbr;
+	return add_branch; /* success */
+
+ out_wbr:
+	kfree(add_branch->br_wbr);
+ out_br:
+	kfree(add_branch);
+ out:
+	return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * test if the branch permission is legal or not.
+ */
+static int test_br(struct inode *inode, int brperm, char *path)
+{
+	int err;
+
+	err = 0;
+	if (unlikely(au_br_writable(brperm) && IS_RDONLY(inode))) {
+		AuErr("write permission for readonly mount or inode, %s\n",
+		      path);
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+/*
+ * returns:
+ * 0: success, the caller will add it
+ * plus: success, it is already unified, the caller should ignore it
+ * minus: error
+ */
+static int test_add(struct super_block *sb, struct au_opt_add *add, int remount)
+{
+	int err;
+	aufs_bindex_t bend, bindex;
+	struct dentry *root;
+	struct inode *inode, *h_inode;
+
+	root = sb->s_root;
+	bend = au_sbend(sb);
+	if (unlikely(bend >= 0
+		     && au_find_dbindex(root, add->path.dentry) >= 0)) {
+		err = 1;
+		if (!remount) {
+			err = -EINVAL;
+			AuErr("%s duplicated\n", add->pathname);
+		}
+		goto out;
+	}
+
+	err = -ENOSPC; /* -E2BIG; */
+	if (unlikely(AUFS_BRANCH_MAX <= add->bindex
+		     || AUFS_BRANCH_MAX - 1 <= bend)) {
+		AuErr("number of branches exceeded %s\n", add->pathname);
+		goto out;
+	}
+
+	err = -EDOM;
+	if (unlikely(add->bindex < 0 || bend + 1 < add->bindex)) {
+		AuErr("bad index %d\n", add->bindex);
+		goto out;
+	}
+
+	inode = add->path.dentry->d_inode;
+	err = -ENOENT;
+	if (unlikely(!inode->i_nlink)) {
+		AuErr("no existence %s\n", add->pathname);
+		goto out;
+	}
+
+	err = -EINVAL;
+	if (unlikely(inode->i_sb == sb)) {
+		AuErr("%s must be outside\n", add->pathname);
+		goto out;
+	}
+
+	if (unlikely(au_test_fs_unsuppoted(inode->i_sb))) {
+		AuErr("unsupported filesystem, %s (%s)\n",
+		      add->pathname, au_sbtype(inode->i_sb));
+		goto out;
+	}
+
+	err = test_br(add->path.dentry->d_inode, add->perm, add->pathname);
+	if (unlikely(err))
+		goto out;
+
+	if (bend < 0)
+		return 0; /* success */
+
+	err = -EINVAL;
+	for (bindex = 0; bindex <= bend; bindex++)
+		if (unlikely(test_overlap(sb, add->path.dentry,
+					  au_h_dptr(root, bindex)))) {
+			AuErr("%s is overlapped\n", add->pathname);
+			goto out;
+		}
+
+	err = 0;
+	if (au_opt_test(au_mntflags(sb), WARN_PERM)) {
+		h_inode = au_h_dptr(root, 0)->d_inode;
+		if ((h_inode->i_mode & S_IALLUGO) != (inode->i_mode & S_IALLUGO)
+		    || h_inode->i_uid != inode->i_uid
+		    || h_inode->i_gid != inode->i_gid)
+			AuWarn("uid/gid/perm %s %u/%u/0%o, %u/%u/0%o\n",
+			       add->pathname,
+			       inode->i_uid, inode->i_gid,
+			       (inode->i_mode & S_IALLUGO),
+			       h_inode->i_uid, h_inode->i_gid,
+			       (h_inode->i_mode & S_IALLUGO));
+	}
+
+ out:
+	return err;
+}
+
+/*
+ * initialize or clean the whiteouts for an adding branch
+ */
+static int au_br_init_wh(struct super_block *sb, struct au_branch *br,
+			 int new_perm, struct dentry *h_root)
+{
+	int err, old_perm;
+	aufs_bindex_t bindex;
+	struct mutex *h_mtx;
+	struct au_wbr *wbr;
+	struct au_hinode *hdir;
+
+	wbr = br->br_wbr;
+	old_perm = br->br_perm;
+	br->br_perm = new_perm;
+	hdir = NULL;
+	h_mtx = NULL;
+	bindex = au_br_index(sb, br->br_id);
+	if (0 <= bindex) {
+		hdir = au_hi(sb->s_root->d_inode, bindex);
+		au_hin_imtx_lock_nested(hdir, AuLsc_I_PARENT);
+	} else {
+		h_mtx = &h_root->d_inode->i_mutex;
+		mutex_lock_nested(h_mtx, AuLsc_I_PARENT);
+	}
+	if (!wbr)
+		err = au_wh_init(h_root, br, sb);
+	else {
+		wbr_wh_write_lock(wbr);
+		err = au_wh_init(h_root, br, sb);
+		wbr_wh_write_unlock(wbr);
+	}
+	if (hdir)
+		au_hin_imtx_unlock(hdir);
+	else
+		mutex_unlock(h_mtx);
+	br->br_perm = old_perm;
+
+	if (!err && wbr && !au_br_writable(new_perm)) {
+		kfree(wbr);
+		br->br_wbr = NULL;
+	}
+
+	return err;
+}
+
+static int au_wbr_init(struct au_branch *br, struct super_block *sb,
+		       int perm, struct path *path)
+{
+	int err;
+	struct au_wbr *wbr;
+
+	wbr = br->br_wbr;
+	au_rw_init(&wbr->wbr_wh_rwsem);
+	memset(wbr->wbr_wh, 0, sizeof(wbr->wbr_wh));
+	atomic_set(&wbr->wbr_wh_running, 0);
+	wbr->wbr_bytes = 0;
+
+	err = au_br_init_wh(sb, br, perm, path->dentry);
+
+	return err;
+}
+
+/* intialize a new branch */
+static int au_br_init(struct au_branch *br, struct super_block *sb,
+		      struct au_opt_add *add)
+{
+	int err;
+
+	err = 0;
+	memset(&br->br_xino, 0, sizeof(br->br_xino));
+	mutex_init(&br->br_xino.xi_nondir_mtx);
+	br->br_perm = add->perm;
+	br->br_mnt = add->path.mnt; /* set first, mntget() later */
+	atomic_set(&br->br_count, 0);
+	br->br_xino_upper = AUFS_XINO_TRUNC_INIT;
+	atomic_set(&br->br_xino_running, 0);
+	br->br_id = au_new_br_id(sb);
+
+	if (au_br_writable(add->perm)) {
+		err = au_wbr_init(br, sb, add->perm, &add->path);
+		if (unlikely(err))
+			goto out;
+	}
+
+	if (au_opt_test(au_mntflags(sb), XINO)) {
+		err = au_xino_br(sb, br, add->path.dentry->d_inode->i_ino,
+				 au_sbr(sb, 0)->br_xino.xi_file, /*do_test*/1);
+		if (unlikely(err)) {
+			AuDebugOn(br->br_xino.xi_file);
+			goto out;
+		}
+	}
+
+	sysaufs_br_init(br);
+	mntget(add->path.mnt);
+
+ out:
+	return err;
+}
+
+static void au_br_do_add_brp(struct au_sbinfo *sbinfo, aufs_bindex_t bindex,
+			     struct au_branch *br, aufs_bindex_t bend,
+			     aufs_bindex_t amount)
+{
+	struct au_branch **brp;
+
+	AuRwMustWriteLock(&sbinfo->si_rwsem);
+
+	brp = sbinfo->si_branch + bindex;
+	memmove(brp + 1, brp, sizeof(*brp) * amount);
+	*brp = br;
+	sbinfo->si_bend++;
+	if (unlikely(bend < 0))
+		sbinfo->si_bend = 0;
+}
+
+static void au_br_do_add_hdp(struct au_dinfo *dinfo, aufs_bindex_t bindex,
+			     aufs_bindex_t bend, aufs_bindex_t amount)
+{
+	struct au_hdentry *hdp;
+
+	AuRwMustWriteLock(&dinfo->di_rwsem);
+
+	hdp = dinfo->di_hdentry + bindex;
+	memmove(hdp + 1, hdp, sizeof(*hdp) * amount);
+	au_h_dentry_init(hdp);
+	dinfo->di_bend++;
+	if (unlikely(bend < 0))
+		dinfo->di_bstart = 0;
+}
+
+static void au_br_do_add_hip(struct au_iinfo *iinfo, aufs_bindex_t bindex,
+			     aufs_bindex_t bend, aufs_bindex_t amount)
+{
+	struct au_hinode *hip;
+
+	AuRwMustWriteLock(&iinfo->ii_rwsem);
+
+	hip = iinfo->ii_hinode + bindex;
+	memmove(hip + 1, hip, sizeof(*hip) * amount);
+	hip->hi_inode = NULL;
+	au_hin_init(hip, NULL);
+	iinfo->ii_bend++;
+	if (unlikely(bend < 0))
+		iinfo->ii_bstart = 0;
+}
+
+static void au_br_do_add(struct super_block *sb, struct dentry *h_dentry,
+			 struct au_branch *br, aufs_bindex_t bindex)
+{
+	struct dentry *root;
+	struct inode *root_inode;
+	aufs_bindex_t bend, amount;
+
+	root = sb->s_root;
+	root_inode = root->d_inode;
+	au_plink_block_maintain(sb);
+	bend = au_sbend(sb);
+	amount = bend + 1 - bindex;
+	au_br_do_add_brp(au_sbi(sb), bindex, br, bend, amount);
+	au_br_do_add_hdp(au_di(root), bindex, bend, amount);
+	au_br_do_add_hip(au_ii(root_inode), bindex, bend, amount);
+	au_set_h_dptr(root, bindex, dget(h_dentry));
+	au_set_h_iptr(root_inode, bindex, au_igrab(h_dentry->d_inode),
+		      /*flags*/0);
+}
+
+int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount)
+{
+	int err;
+	unsigned long long maxb;
+	aufs_bindex_t bend, add_bindex;
+	struct dentry *root, *h_dentry;
+	struct inode *root_inode;
+	struct au_branch *add_branch;
+
+	root = sb->s_root;
+	root_inode = root->d_inode;
+	IMustLock(root_inode);
+	err = test_add(sb, add, remount);
+	if (unlikely(err < 0))
+		goto out;
+	if (err) {
+		err = 0;
+		goto out; /* success */
+	}
+
+	bend = au_sbend(sb);
+	add_branch = au_br_alloc(sb, bend + 2, add->perm);
+	err = PTR_ERR(add_branch);
+	if (IS_ERR(add_branch))
+		goto out;
+
+	err = au_br_init(add_branch, sb, add);
+	if (unlikely(err)) {
+		au_br_do_free(add_branch);
+		goto out;
+	}
+
+	add_bindex = add->bindex;
+	h_dentry = add->path.dentry;
+	if (!remount)
+		au_br_do_add(sb, h_dentry, add_branch, add_bindex);
+	else {
+		sysaufs_brs_del(sb, add_bindex);
+		au_br_do_add(sb, h_dentry, add_branch, add_bindex);
+		sysaufs_brs_add(sb, add_bindex);
+	}
+
+	if (!add_bindex)
+		au_cpup_attr_all(root_inode, /*force*/1);
+	else
+		au_add_nlink(root_inode, h_dentry->d_inode);
+	maxb = h_dentry->d_sb->s_maxbytes;
+	if (sb->s_maxbytes < maxb)
+		sb->s_maxbytes = maxb;
+
+	/*
+	 * this test/set prevents aufs from handling unnecesary inotify events
+	 * of xino files, in a case of re-adding a writable branch which was
+	 * once detached from aufs.
+	 */
+	if (au_xino_brid(sb) < 0
+	    && au_br_writable(add_branch->br_perm)
+	    && !au_test_fs_bad_xino(h_dentry->d_sb)
+	    && add_branch->br_xino.xi_file
+	    && add_branch->br_xino.xi_file->f_dentry->d_parent == h_dentry)
+		au_xino_brid_set(sb, add_branch->br_id);
+
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * delete a branch
+ */
+
+/* to show the line number, do not make it inlined function */
+#define AuVerbose(do_info, fmt, args...) do { \
+	if (do_info) \
+		AuInfo(fmt, ##args); \
+} while (0)
+
+/*
+ * test if the branch is deletable or not.
+ */
+static int test_dentry_busy(struct dentry *root, aufs_bindex_t bindex,
+			    unsigned int sigen)
+{
+	int err, i, j, ndentry;
+	aufs_bindex_t bstart, bend;
+	unsigned char verbose;
+	struct au_dcsub_pages dpages;
+	struct au_dpage *dpage;
+	struct dentry *d;
+	struct inode *inode;
+
+	err = au_dpages_init(&dpages, GFP_NOFS);
+	if (unlikely(err))
+		goto out;
+	err = au_dcsub_pages(&dpages, root, NULL, NULL);
+	if (unlikely(err))
+		goto out_dpages;
+
+	verbose = !!au_opt_test(au_mntflags(root->d_sb), VERBOSE);
+	for (i = 0; !err && i < dpages.ndpage; i++) {
+		dpage = dpages.dpages + i;
+		ndentry = dpage->ndentry;
+		for (j = 0; !err && j < ndentry; j++) {
+			d = dpage->dentries[j];
+			AuDebugOn(!atomic_read(&d->d_count));
+			inode = d->d_inode;
+			if (au_digen(d) == sigen && au_iigen(inode) == sigen)
+				di_read_lock_child(d, AuLock_IR);
+			else {
+				di_write_lock_child(d);
+				err = au_reval_dpath(d, sigen);
+				if (!err)
+					di_downgrade_lock(d, AuLock_IR);
+				else {
+					di_write_unlock(d);
+					break;
+				}
+			}
+
+			bstart = au_dbstart(d);
+			bend = au_dbend(d);
+			if (bstart <= bindex
+			    && bindex <= bend
+			    && au_h_dptr(d, bindex)
+			    && (!S_ISDIR(inode->i_mode) || bstart == bend)) {
+				err = -EBUSY;
+				AuVerbose(verbose, "busy %.*s\n", AuDLNPair(d));
+			}
+			di_read_unlock(d, AuLock_IR);
+		}
+	}
+
+ out_dpages:
+	au_dpages_free(&dpages);
+ out:
+	return err;
+}
+
+static int test_inode_busy(struct super_block *sb, aufs_bindex_t bindex,
+			   unsigned int sigen)
+{
+	int err;
+	struct inode *i;
+	aufs_bindex_t bstart, bend;
+	unsigned char verbose;
+
+	err = 0;
+	verbose = !!au_opt_test(au_mntflags(sb), VERBOSE);
+	list_for_each_entry(i, &sb->s_inodes, i_sb_list) {
+		AuDebugOn(!atomic_read(&i->i_count));
+		if (!list_empty(&i->i_dentry))
+			continue;
+
+		if (au_iigen(i) == sigen)
+			ii_read_lock_child(i);
+		else {
+			ii_write_lock_child(i);
+			err = au_refresh_hinode_self(i, /*do_attr*/1);
+			if (!err)
+				ii_downgrade_lock(i);
+			else {
+				ii_write_unlock(i);
+				break;
+			}
+		}
+
+		bstart = au_ibstart(i);
+		bend = au_ibend(i);
+		if (bstart <= bindex
+		    && bindex <= bend
+		    && au_h_iptr(i, bindex)
+		    && (!S_ISDIR(i->i_mode) || bstart == bend)) {
+			err = -EBUSY;
+			AuVerbose(verbose, "busy i%lu\n", i->i_ino);
+			ii_read_unlock(i);
+			break;
+		}
+		ii_read_unlock(i);
+	}
+
+	return err;
+}
+
+static int test_children_busy(struct dentry *root, aufs_bindex_t bindex)
+{
+	int err;
+	unsigned int sigen;
+
+	sigen = au_sigen(root->d_sb);
+	DiMustNoWaiters(root);
+	IiMustNoWaiters(root->d_inode);
+	di_write_unlock(root);
+	err = test_dentry_busy(root, bindex, sigen);
+	if (!err)
+		err = test_inode_busy(root->d_sb, bindex, sigen);
+	di_write_lock_child(root); /* aufs_write_lock() calls ..._child() */
+
+	return err;
+}
+
+static void au_br_do_del_brp(struct au_sbinfo *sbinfo,
+			     const aufs_bindex_t bindex,
+			     const aufs_bindex_t bend)
+{
+	struct au_branch **brp, **p;
+
+	AuRwMustWriteLock(&sbinfo->si_rwsem);
+
+	brp = sbinfo->si_branch + bindex;
+	if (bindex < bend)
+		memmove(brp, brp + 1, sizeof(*brp) * (bend - bindex));
+	sbinfo->si_branch[0 + bend] = NULL;
+	sbinfo->si_bend--;
+
+	p = krealloc(sbinfo->si_branch, sizeof(*p) * bend, GFP_NOFS);
+	if (p)
+		sbinfo->si_branch = p;
+}
+
+static void au_br_do_del_hdp(struct au_dinfo *dinfo, const aufs_bindex_t bindex,
+			     const aufs_bindex_t bend)
+{
+	struct au_hdentry *hdp, *p;
+
+	AuRwMustWriteLock(&dinfo->di_rwsem);
+
+	hdp = dinfo->di_hdentry + bindex;
+	if (bindex < bend)
+		memmove(hdp, hdp + 1, sizeof(*hdp) * (bend - bindex));
+	dinfo->di_hdentry[0 + bend].hd_dentry = NULL;
+	dinfo->di_bend--;
+
+	p = krealloc(dinfo->di_hdentry, sizeof(*p) * bend, GFP_NOFS);
+	if (p)
+		dinfo->di_hdentry = p;
+}
+
+static void au_br_do_del_hip(struct au_iinfo *iinfo, const aufs_bindex_t bindex,
+			     const aufs_bindex_t bend)
+{
+	struct au_hinode *hip, *p;
+
+	AuRwMustWriteLock(&iinfo->ii_rwsem);
+
+	hip = iinfo->ii_hinode + bindex;
+	if (bindex < bend)
+		memmove(hip, hip + 1, sizeof(*hip) * (bend - bindex));
+	iinfo->ii_hinode[0 + bend].hi_inode = NULL;
+	au_hin_init(iinfo->ii_hinode + bend, NULL);
+	iinfo->ii_bend--;
+
+	p = krealloc(iinfo->ii_hinode, sizeof(*p) * bend, GFP_NOFS);
+	if (p)
+		iinfo->ii_hinode = p;
+}
+
+static void au_br_do_del(struct super_block *sb, aufs_bindex_t bindex,
+			 struct au_branch *br)
+{
+	aufs_bindex_t bend;
+	struct au_sbinfo *sbinfo;
+	struct dentry *root;
+	struct inode *inode;
+
+	SiMustWriteLock(sb);
+
+	root = sb->s_root;
+	inode = root->d_inode;
+	au_plink_block_maintain(sb);
+	sbinfo = au_sbi(sb);
+	bend = sbinfo->si_bend;
+
+	dput(au_h_dptr(root, bindex));
+	au_hiput(au_hi(inode, bindex));
+	au_br_do_free(br);
+
+	au_br_do_del_brp(sbinfo, bindex, bend);
+	au_br_do_del_hdp(au_di(root), bindex, bend);
+	au_br_do_del_hip(au_ii(inode), bindex, bend);
+}
+
+int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount)
+{
+	int err, rerr, i;
+	unsigned int mnt_flags;
+	aufs_bindex_t bindex, bend, br_id;
+	unsigned char do_wh, verbose;
+	struct au_branch *br;
+	struct au_wbr *wbr;
+
+	err = 0;
+	bindex = au_find_dbindex(sb->s_root, del->h_path.dentry);
+	if (bindex < 0) {
+		if (remount)
+			goto out; /* success */
+		err = -ENOENT;
+		AuErr("%s no such branch\n", del->pathname);
+		goto out;
+	}
+	AuDbg("bindex b%d\n", bindex);
+
+	err = -EBUSY;
+	mnt_flags = au_mntflags(sb);
+	verbose = !!au_opt_test(mnt_flags, VERBOSE);
+	bend = au_sbend(sb);
+	if (unlikely(!bend)) {
+		AuVerbose(verbose, "no more branches left\n");
+		goto out;
+	}
+	br = au_sbr(sb, bindex);
+	i = atomic_read(&br->br_count);
+	if (unlikely(i)) {
+		AuVerbose(verbose, "%d file(s) opened\n", i);
+		goto out;
+	}
+
+	wbr = br->br_wbr;
+	do_wh = wbr && (wbr->wbr_whbase || wbr->wbr_plink || wbr->wbr_orph);
+	if (do_wh) {
+		/* instead of WbrWhMustWriteLock(wbr) */
+		SiMustWriteLock(sb);
+		for (i = 0; i < AuBrWh_Last; i++) {
+			dput(wbr->wbr_wh[i]);
+			wbr->wbr_wh[i] = NULL;
+		}
+	}
+
+	err = test_children_busy(sb->s_root, bindex);
+	if (unlikely(err)) {
+		if (do_wh)
+			goto out_wh;
+		goto out;
+	}
+
+	err = 0;
+	br_id = br->br_id;
+	if (!remount)
+		au_br_do_del(sb, bindex, br);
+	else {
+		sysaufs_brs_del(sb, bindex);
+		au_br_do_del(sb, bindex, br);
+		sysaufs_brs_add(sb, bindex);
+	}
+
+	if (!bindex)
+		au_cpup_attr_all(sb->s_root->d_inode, /*force*/1);
+	else
+		au_sub_nlink(sb->s_root->d_inode, del->h_path.dentry->d_inode);
+	if (au_opt_test(mnt_flags, PLINK))
+		au_plink_half_refresh(sb, br_id);
+
+	if (sb->s_maxbytes == del->h_path.dentry->d_sb->s_maxbytes) {
+		bend--;
+		sb->s_maxbytes = 0;
+		for (bindex = 0; bindex <= bend; bindex++) {
+			unsigned long long maxb;
+
+			maxb = au_sbr_sb(sb, bindex)->s_maxbytes;
+			if (sb->s_maxbytes < maxb)
+				sb->s_maxbytes = maxb;
+		}
+	}
+
+	if (au_xino_brid(sb) == br->br_id)
+		au_xino_brid_set(sb, -1);
+	goto out; /* success */
+
+ out_wh:
+	/* revert */
+	rerr = au_br_init_wh(sb, br, br->br_perm, del->h_path.dentry);
+	if (rerr)
+		AuWarn("failed re-creating base whiteout, %s. (%d)\n",
+		       del->pathname, rerr);
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * change a branch permission
+ */
+
+static int do_need_sigen_inc(int a, int b)
+{
+	return au_br_whable(a) && !au_br_whable(b);
+}
+
+static int need_sigen_inc(int old, int new)
+{
+	return do_need_sigen_inc(old, new)
+		|| do_need_sigen_inc(new, old);
+}
+
+static int au_br_mod_files_ro(struct super_block *sb, aufs_bindex_t bindex)
+{
+	int err;
+	unsigned long n, ul, bytes, files;
+	aufs_bindex_t bstart;
+	struct file *file, *hf, **a;
+	const int step_bytes = 1024, /* memory allocation unit */
+		step_files = step_bytes / sizeof(*a);
+
+	err = -ENOMEM;
+	n = 0;
+	bytes = step_bytes;
+	files = step_files;
+	a = kmalloc(bytes, GFP_NOFS);
+	if (unlikely(!a))
+		goto out;
+
+	/* no need file_list_lock() since sbinfo is locked? defered? */
+	list_for_each_entry(file, &sb->s_files, f_u.fu_list) {
+		if (special_file(file->f_dentry->d_inode->i_mode))
+			continue;
+
+		AuDbg("%.*s\n", AuDLNPair(file->f_dentry));
+		fi_read_lock(file);
+		if (unlikely(au_test_mmapped(file))) {
+			err = -EBUSY;
+			FiMustNoWaiters(file);
+			fi_read_unlock(file);
+			goto out_free;
+		}
+
+		bstart = au_fbstart(file);
+		if (!S_ISREG(file->f_dentry->d_inode->i_mode)
+		    || !(file->f_mode & FMODE_WRITE)
+		    || bstart != bindex) {
+			FiMustNoWaiters(file);
+			fi_read_unlock(file);
+			continue;
+		}
+
+		hf = au_h_fptr(file, bstart);
+		FiMustNoWaiters(file);
+		fi_read_unlock(file);
+
+		if (n < files)
+			a[n++] = hf;
+		else {
+			void *p;
+
+			err = -ENOMEM;
+			bytes += step_bytes;
+			files += step_files;
+			p = krealloc(a, bytes, GFP_NOFS);
+			if (p) {
+				a = p;
+				a[n++] = hf;
+			} else
+				goto out_free;
+		}
+	}
+
+	err = 0;
+	for (ul = 0; ul < n; ul++) {
+		/* todo: already flushed? */
+		/* cf. fs/super.c:mark_files_ro() */
+		hf = a[ul];
+		hf->f_mode &= ~FMODE_WRITE;
+		if (!file_check_writeable(hf)) {
+			file_release_write(hf);
+			mnt_drop_write(hf->f_vfsmnt);
+		}
+	}
+
+ out_free:
+	kfree(a);
+ out:
+	return err;
+}
+
+int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
+	      int *do_update)
+{
+	int err, rerr;
+	aufs_bindex_t bindex;
+	struct dentry *root;
+	struct au_branch *br;
+
+	root = sb->s_root;
+	au_plink_block_maintain(sb);
+	bindex = au_find_dbindex(root, mod->h_root);
+	if (bindex < 0) {
+		if (remount)
+			return 0; /* success */
+		err = -ENOENT;
+		AuErr("%s no such branch\n", mod->path);
+		goto out;
+	}
+	AuDbg("bindex b%d\n", bindex);
+
+	err = test_br(mod->h_root->d_inode, mod->perm, mod->path);
+	if (unlikely(err))
+		goto out;
+
+	br = au_sbr(sb, bindex);
+	if (br->br_perm == mod->perm)
+		return 0; /* success */
+
+	if (au_br_writable(br->br_perm)) {
+		/* remove whiteout base */
+		err = au_br_init_wh(sb, br, mod->perm, mod->h_root);
+		if (unlikely(err))
+			goto out;
+
+		if (!au_br_writable(mod->perm)) {
+			/* rw --> ro, file might be mmapped */
+			DiMustNoWaiters(root);
+			IiMustNoWaiters(root->d_inode);
+			di_write_unlock(root);
+			err = au_br_mod_files_ro(sb, bindex);
+			/* aufs_write_lock() calls ..._child() */
+			di_write_lock_child(root);
+
+			if (unlikely(err)) {
+				rerr = -ENOMEM;
+				br->br_wbr = kmalloc(sizeof(*br->br_wbr),
+						     GFP_NOFS);
+				if (br->br_wbr)
+					rerr = au_br_init_wh
+						(sb, br, br->br_perm,
+						 mod->h_root);
+				if (unlikely(rerr)) {
+					AuIOErr("nested error %d (%d)\n",
+						rerr, err);
+					br->br_perm = mod->perm;
+				}
+			}
+		}
+	} else if (au_br_writable(mod->perm)) {
+		/* ro --> rw */
+		err = -ENOMEM;
+		br->br_wbr = kmalloc(sizeof(*br->br_wbr), GFP_NOFS);
+		if (br->br_wbr) {
+			struct path path = {
+				.mnt	= br->br_mnt,
+				.dentry	= mod->h_root
+			};
+
+			err = au_wbr_init(br, sb, mod->perm, &path);
+			if (unlikely(err)) {
+				kfree(br->br_wbr);
+				br->br_wbr = NULL;
+			}
+		}
+	}
+
+	if (!err) {
+		*do_update |= need_sigen_inc(br->br_perm, mod->perm);
+		br->br_perm = mod->perm;
+	}
+
+ out:
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/branch.h linux-2.6.31.4/fs/aufs/branch.h
--- linux-2.6.31.4.orig/fs/aufs/branch.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/branch.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * branch filesystems and xino for them
+ */
+
+#ifndef __AUFS_BRANCH_H__
+#define __AUFS_BRANCH_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/aufs_type.h>
+#include "rwsem.h"
+#include "super.h"
+
+/* ---------------------------------------------------------------------- */
+
+/* a xino file */
+struct au_xino_file {
+	struct file		*xi_file;
+	struct mutex		xi_nondir_mtx;
+
+	/* todo: make xino files an array to support huge inode number */
+
+#ifdef CONFIG_DEBUG_FS
+	struct dentry		 *xi_dbgaufs;
+#endif
+};
+
+/* members for writable branch only */
+enum {AuBrWh_BASE, AuBrWh_PLINK, AuBrWh_ORPH, AuBrWh_Last};
+struct au_wbr {
+	struct au_rwsem		wbr_wh_rwsem;
+	struct dentry		*wbr_wh[AuBrWh_Last];
+	atomic_t 		wbr_wh_running;
+#define wbr_whbase		wbr_wh[AuBrWh_BASE]	/* whiteout base */
+#define wbr_plink		wbr_wh[AuBrWh_PLINK]	/* pseudo-link dir */
+#define wbr_orph		wbr_wh[AuBrWh_ORPH]	/* dir for orphans */
+
+	/* mfs mode */
+	unsigned long long	wbr_bytes;
+};
+
+/* protected by superblock rwsem */
+struct au_branch {
+	struct au_xino_file	br_xino;
+
+	aufs_bindex_t		br_id;
+
+	int			br_perm;
+	struct vfsmount		*br_mnt;
+	atomic_t		br_count;
+
+	struct au_wbr		*br_wbr;
+
+	/* xino truncation */
+	blkcnt_t		br_xino_upper;	/* watermark in blocks */
+	atomic_t		br_xino_running;
+
+#ifdef CONFIG_SYSFS
+	/* an entry under sysfs per mount-point */
+	char			br_name[8];
+	struct attribute	br_attr;
+#endif
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* branch permission and attribute */
+enum {
+	AuBrPerm_RW,		/* writable, linkable wh */
+	AuBrPerm_RO,		/* readonly, no wh */
+	AuBrPerm_RR,		/* natively readonly, no wh */
+
+	AuBrPerm_RWNoLinkWH,	/* un-linkable whiteouts */
+
+	AuBrPerm_ROWH,		/* whiteout-able */
+	AuBrPerm_RRWH,		/* whiteout-able */
+
+	AuBrPerm_Last
+};
+
+static inline int au_br_writable(int brperm)
+{
+	return brperm == AuBrPerm_RW || brperm == AuBrPerm_RWNoLinkWH;
+}
+
+static inline int au_br_whable(int brperm)
+{
+	return brperm == AuBrPerm_RW
+		|| brperm == AuBrPerm_ROWH
+		|| brperm == AuBrPerm_RRWH;
+}
+
+static inline int au_br_rdonly(struct au_branch *br)
+{
+	return ((br->br_mnt->mnt_sb->s_flags & MS_RDONLY)
+		|| !au_br_writable(br->br_perm))
+		? -EROFS : 0;
+}
+
+static inline int au_br_hinotifyable(int brperm __maybe_unused)
+{
+#ifdef CONFIG_AUFS_HINOTIFY
+	return brperm != AuBrPerm_RR && brperm != AuBrPerm_RRWH;
+#else
+	return 0;
+#endif
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* branch.c */
+struct au_sbinfo;
+void au_br_free(struct au_sbinfo *sinfo);
+int au_br_index(struct super_block *sb, aufs_bindex_t br_id);
+struct au_opt_add;
+int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount);
+struct au_opt_del;
+int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount);
+struct au_opt_mod;
+int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
+	      int *do_update);
+
+/* xino.c */
+static const loff_t au_loff_max = LLONG_MAX;
+
+int au_xib_trunc(struct super_block *sb);
+ssize_t xino_fread(au_readf_t func, struct file *file, void *buf, size_t size,
+		   loff_t *pos);
+ssize_t xino_fwrite(au_writef_t func, struct file *file, void *buf, size_t size,
+		    loff_t *pos);
+struct file *au_xino_create2(struct file *base_file, struct file *copy_src);
+struct file *au_xino_create(struct super_block *sb, char *fname, int silent);
+ino_t au_xino_new_ino(struct super_block *sb);
+int au_xino_write0(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		   ino_t ino);
+int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		  ino_t ino);
+int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		 ino_t *ino);
+int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t hino,
+	       struct file *base_file, int do_test);
+int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex);
+
+struct au_opt_xino;
+int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount);
+void au_xino_clr(struct super_block *sb);
+struct file *au_xino_def(struct super_block *sb);
+int au_xino_path(struct seq_file *seq, struct file *file);
+
+/* ---------------------------------------------------------------------- */
+
+/* Superblock to branch */
+static inline
+aufs_bindex_t au_sbr_id(struct super_block *sb, aufs_bindex_t bindex)
+{
+	return au_sbr(sb, bindex)->br_id;
+}
+
+static inline
+struct vfsmount *au_sbr_mnt(struct super_block *sb, aufs_bindex_t bindex)
+{
+	return au_sbr(sb, bindex)->br_mnt;
+}
+
+static inline
+struct super_block *au_sbr_sb(struct super_block *sb, aufs_bindex_t bindex)
+{
+	return au_sbr_mnt(sb, bindex)->mnt_sb;
+}
+
+static inline void au_sbr_put(struct super_block *sb, aufs_bindex_t bindex)
+{
+	atomic_dec_return(&au_sbr(sb, bindex)->br_count);
+}
+
+static inline int au_sbr_perm(struct super_block *sb, aufs_bindex_t bindex)
+{
+	return au_sbr(sb, bindex)->br_perm;
+}
+
+static inline int au_sbr_whable(struct super_block *sb, aufs_bindex_t bindex)
+{
+	return au_br_whable(au_sbr_perm(sb, bindex));
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * wbr_wh_read_lock, wbr_wh_write_lock
+ * wbr_wh_read_unlock, wbr_wh_write_unlock, wbr_wh_downgrade_lock
+ */
+AuSimpleRwsemFuncs(wbr_wh, struct au_wbr *wbr, &wbr->wbr_wh_rwsem);
+
+#define WbrWhMustNoWaiters(wbr)	AuRwMustNoWaiters(&wbr->wbr_wh_rwsem)
+#define WbrWhMustAnyLock(wbr)	AuRwMustAnyLock(&wbr->wbr_wh_rwsem)
+#define WbrWhMustWriteLock(wbr)	AuRwMustWriteLock(&wbr->wbr_wh_rwsem)
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_BRANCH_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/cpup.c linux-2.6.31.4/fs/aufs/cpup.c
--- linux-2.6.31.4.orig/fs/aufs/cpup.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/cpup.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,1048 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * copy-up functions, see wbr_policy.c for copy-down
+ */
+
+#include <linux/file.h>
+#include <linux/fs_stack.h>
+#include <linux/mm.h>
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+void au_cpup_attr_flags(struct inode *dst, struct inode *src)
+{
+	const unsigned int mask = S_DEAD | S_SWAPFILE | S_PRIVATE
+		| S_NOATIME | S_NOCMTIME;
+
+	dst->i_flags |= src->i_flags & ~mask;
+	if (au_test_fs_notime(dst->i_sb))
+		dst->i_flags |= S_NOATIME | S_NOCMTIME;
+}
+
+void au_cpup_attr_timesizes(struct inode *inode)
+{
+	struct inode *h_inode;
+
+	h_inode = au_h_iptr(inode, au_ibstart(inode));
+	fsstack_copy_attr_times(inode, h_inode);
+	vfsub_copy_inode_size(inode, h_inode);
+}
+
+void au_cpup_attr_nlink(struct inode *inode, int force)
+{
+	struct inode *h_inode;
+	struct super_block *sb;
+	aufs_bindex_t bindex, bend;
+
+	sb = inode->i_sb;
+	bindex = au_ibstart(inode);
+	h_inode = au_h_iptr(inode, bindex);
+	if (!force
+	    && !S_ISDIR(h_inode->i_mode)
+	    && au_opt_test(au_mntflags(sb), PLINK)
+	    && au_plink_test(inode))
+		return;
+
+	inode->i_nlink = h_inode->i_nlink;
+
+	/*
+	 * fewer nlink makes find(1) noisy, but larger nlink doesn't.
+	 * it may includes whplink directory.
+	 */
+	if (S_ISDIR(h_inode->i_mode)) {
+		bend = au_ibend(inode);
+		for (bindex++; bindex <= bend; bindex++) {
+			h_inode = au_h_iptr(inode, bindex);
+			if (h_inode)
+				au_add_nlink(inode, h_inode);
+		}
+	}
+}
+
+void au_cpup_attr_changeable(struct inode *inode)
+{
+	struct inode *h_inode;
+
+	h_inode = au_h_iptr(inode, au_ibstart(inode));
+	inode->i_mode = h_inode->i_mode;
+	inode->i_uid = h_inode->i_uid;
+	inode->i_gid = h_inode->i_gid;
+	au_cpup_attr_timesizes(inode);
+	au_cpup_attr_flags(inode, h_inode);
+}
+
+void au_cpup_igen(struct inode *inode, struct inode *h_inode)
+{
+	struct au_iinfo *iinfo = au_ii(inode);
+
+	IiMustWriteLock(inode);
+
+	iinfo->ii_higen = h_inode->i_generation;
+	iinfo->ii_hsb1 = h_inode->i_sb;
+}
+
+void au_cpup_attr_all(struct inode *inode, int force)
+{
+	struct inode *h_inode;
+
+	h_inode = au_h_iptr(inode, au_ibstart(inode));
+	au_cpup_attr_changeable(inode);
+	if (inode->i_nlink > 0)
+		au_cpup_attr_nlink(inode, force);
+	inode->i_rdev = h_inode->i_rdev;
+	inode->i_blkbits = h_inode->i_blkbits;
+	au_cpup_igen(inode, h_inode);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* Note: dt_dentry and dt_h_dentry are not dget/dput-ed */
+
+/* keep the timestamps of the parent dir when cpup */
+void au_dtime_store(struct au_dtime *dt, struct dentry *dentry,
+		    struct path *h_path)
+{
+	struct inode *h_inode;
+
+	dt->dt_dentry = dentry;
+	dt->dt_h_path = *h_path;
+	h_inode = h_path->dentry->d_inode;
+	dt->dt_atime = h_inode->i_atime;
+	dt->dt_mtime = h_inode->i_mtime;
+	/* smp_mb(); */
+}
+
+void au_dtime_revert(struct au_dtime *dt)
+{
+	struct iattr attr;
+	int err;
+
+	attr.ia_atime = dt->dt_atime;
+	attr.ia_mtime = dt->dt_mtime;
+	attr.ia_valid = ATTR_FORCE | ATTR_MTIME | ATTR_MTIME_SET
+		| ATTR_ATIME | ATTR_ATIME_SET;
+
+	err = vfsub_notify_change(&dt->dt_h_path, &attr);
+	if (unlikely(err))
+		AuWarn("restoring timestamps failed(%d). ignored\n", err);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static noinline_for_stack
+int cpup_iattr(struct dentry *dst, aufs_bindex_t bindex, struct dentry *h_src)
+{
+	int err, sbits;
+	struct iattr ia;
+	struct path h_path;
+	struct inode *h_isrc, *h_idst;
+
+	h_path.dentry = au_h_dptr(dst, bindex);
+	h_idst = h_path.dentry->d_inode;
+	h_path.mnt = au_sbr_mnt(dst->d_sb, bindex);
+	h_isrc = h_src->d_inode;
+	ia.ia_valid = ATTR_FORCE | ATTR_UID | ATTR_GID
+		| ATTR_ATIME | ATTR_MTIME
+		| ATTR_ATIME_SET | ATTR_MTIME_SET;
+	ia.ia_uid = h_isrc->i_uid;
+	ia.ia_gid = h_isrc->i_gid;
+	ia.ia_atime = h_isrc->i_atime;
+	ia.ia_mtime = h_isrc->i_mtime;
+	if (h_idst->i_mode != h_isrc->i_mode
+	    && !S_ISLNK(h_idst->i_mode)) {
+		ia.ia_valid |= ATTR_MODE;
+		ia.ia_mode = h_isrc->i_mode;
+	}
+	sbits = !!(h_isrc->i_mode & (S_ISUID | S_ISGID));
+	au_cpup_attr_flags(h_idst, h_isrc);
+	err = vfsub_notify_change(&h_path, &ia);
+
+	/* is this nfs only? */
+	if (!err && sbits && au_test_nfs(h_path.dentry->d_sb)) {
+		ia.ia_valid = ATTR_FORCE | ATTR_MODE;
+		ia.ia_mode = h_isrc->i_mode;
+		err = vfsub_notify_change(&h_path, &ia);
+	}
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_do_copy_file(struct file *dst, struct file *src, loff_t len,
+			   char *buf, unsigned long blksize)
+{
+	int err;
+	size_t sz, rbytes, wbytes;
+	unsigned char all_zero;
+	char *p, *zp;
+	struct mutex *h_mtx;
+	/* reduce stack usage */
+	struct iattr *ia;
+
+	zp = page_address(ZERO_PAGE(0));
+	if (unlikely(!zp))
+		return -ENOMEM; /* possible? */
+
+	err = 0;
+	all_zero = 0;
+	while (len) {
+		AuDbg("len %lld\n", len);
+		sz = blksize;
+		if (len < blksize)
+			sz = len;
+
+		rbytes = 0;
+		/* todo: signal_pending? */
+		while (!rbytes || err == -EAGAIN || err == -EINTR) {
+			rbytes = vfsub_read_k(src, buf, sz, &src->f_pos);
+			err = rbytes;
+		}
+		if (unlikely(err < 0))
+			break;
+
+		all_zero = 0;
+		if (len >= rbytes && rbytes == blksize)
+			all_zero = !memcmp(buf, zp, rbytes);
+		if (!all_zero) {
+			wbytes = rbytes;
+			p = buf;
+			while (wbytes) {
+				size_t b;
+
+				b = vfsub_write_k(dst, p, wbytes, &dst->f_pos);
+				err = b;
+				/* todo: signal_pending? */
+				if (unlikely(err == -EAGAIN || err == -EINTR))
+					continue;
+				if (unlikely(err < 0))
+					break;
+				wbytes -= b;
+				p += b;
+			}
+		} else {
+			loff_t res;
+
+			AuLabel(hole);
+			res = vfsub_llseek(dst, rbytes, SEEK_CUR);
+			err = res;
+			if (unlikely(res < 0))
+				break;
+		}
+		len -= rbytes;
+		err = 0;
+	}
+
+	/* the last block may be a hole */
+	if (!err && all_zero) {
+		AuLabel(last hole);
+
+		err = 1;
+		if (au_test_nfs(dst->f_dentry->d_sb)) {
+			/* nfs requires this step to make last hole */
+			/* is this only nfs? */
+			do {
+				/* todo: signal_pending? */
+				err = vfsub_write_k(dst, "\0", 1, &dst->f_pos);
+			} while (err == -EAGAIN || err == -EINTR);
+			if (err == 1)
+				dst->f_pos--;
+		}
+
+		if (err == 1) {
+			ia = (void *)buf;
+			ia->ia_size = dst->f_pos;
+			ia->ia_valid = ATTR_SIZE | ATTR_FILE;
+			ia->ia_file = dst;
+			h_mtx = &dst->f_dentry->d_inode->i_mutex;
+			mutex_lock_nested(h_mtx, AuLsc_I_CHILD2);
+			err = vfsub_notify_change(&dst->f_path, ia);
+			mutex_unlock(h_mtx);
+		}
+	}
+
+	return err;
+}
+
+int au_copy_file(struct file *dst, struct file *src, loff_t len)
+{
+	int err;
+	unsigned long blksize;
+	unsigned char do_kfree;
+	char *buf;
+
+	err = -ENOMEM;
+	blksize = dst->f_dentry->d_sb->s_blocksize;
+	if (!blksize || PAGE_SIZE < blksize)
+		blksize = PAGE_SIZE;
+	AuDbg("blksize %lu\n", blksize);
+	do_kfree = (blksize != PAGE_SIZE && blksize >= sizeof(struct iattr *));
+	if (do_kfree)
+		buf = kmalloc(blksize, GFP_NOFS);
+	else
+		buf = (void *)__get_free_page(GFP_NOFS);
+	if (unlikely(!buf))
+		goto out;
+
+	if (len > (1 << 22))
+		AuDbg("copying a large file %lld\n", (long long)len);
+
+	src->f_pos = 0;
+	dst->f_pos = 0;
+	err = au_do_copy_file(dst, src, len, buf, blksize);
+	if (do_kfree)
+		kfree(buf);
+	else
+		free_page((unsigned long)buf);
+
+ out:
+	return err;
+}
+
+/*
+ * to support a sparse file which is opened with O_APPEND,
+ * we need to close the file.
+ */
+static int au_cp_regular(struct dentry *dentry, aufs_bindex_t bdst,
+			aufs_bindex_t bsrc, loff_t len)
+{
+	int err, i;
+	enum { SRC, DST };
+	struct {
+		aufs_bindex_t bindex;
+		unsigned int flags;
+		struct dentry *dentry;
+		struct file *file;
+		void *label, *label_file;
+	} *f, file[] = {
+		{
+			.bindex = bsrc,
+			.flags = O_RDONLY | O_NOATIME | O_LARGEFILE,
+			.file = NULL,
+			.label = &&out,
+			.label_file = &&out_src
+		},
+		{
+			.bindex = bdst,
+			.flags = O_WRONLY | O_NOATIME | O_LARGEFILE,
+			.file = NULL,
+			.label = &&out_src,
+			.label_file = &&out_dst
+		}
+	};
+	struct super_block *sb;
+
+	/* bsrc branch can be ro/rw. */
+	sb = dentry->d_sb;
+	f = file;
+	for (i = 0; i < 2; i++, f++) {
+		f->dentry = au_h_dptr(dentry, f->bindex);
+		f->file = au_h_open(dentry, f->bindex, f->flags, /*file*/NULL);
+		err = PTR_ERR(f->file);
+		if (IS_ERR(f->file))
+			goto *f->label;
+		err = -EINVAL;
+		if (unlikely(!f->file->f_op))
+			goto *f->label_file;
+	}
+
+	/* try stopping to update while we copyup */
+	IMustLock(file[SRC].dentry->d_inode);
+	err = au_copy_file(file[DST].file, file[SRC].file, len);
+
+ out_dst:
+	fput(file[DST].file);
+	au_sbr_put(sb, file[DST].bindex);
+ out_src:
+	fput(file[SRC].file);
+	au_sbr_put(sb, file[SRC].bindex);
+ out:
+	return err;
+}
+
+static int au_do_cpup_regular(struct dentry *dentry, aufs_bindex_t bdst,
+			      aufs_bindex_t bsrc, loff_t len,
+			      struct inode *h_dir, struct path *h_path)
+{
+	int err, rerr;
+	loff_t l;
+
+	err = 0;
+	l = i_size_read(au_h_iptr(dentry->d_inode, bsrc));
+	if (len == -1 || l < len)
+		len = l;
+	if (len)
+		err = au_cp_regular(dentry, bdst, bsrc, len);
+	if (!err)
+		goto out; /* success */
+
+	rerr = vfsub_unlink(h_dir, h_path, /*force*/0);
+	if (rerr) {
+		AuIOErr("failed unlinking cpup-ed %.*s(%d, %d)\n",
+			AuDLNPair(h_path->dentry), err, rerr);
+		err = -EIO;
+	}
+
+ out:
+	return err;
+}
+
+static int au_do_cpup_symlink(struct path *h_path, struct dentry *h_src,
+			      struct inode *h_dir)
+{
+	int err, symlen;
+	mm_segment_t old_fs;
+	char *sym;
+
+	err = -ENOSYS;
+	if (unlikely(!h_src->d_inode->i_op->readlink))
+		goto out;
+
+	err = -ENOMEM;
+	sym = __getname();
+	if (unlikely(!sym))
+		goto out;
+
+	old_fs = get_fs();
+	set_fs(KERNEL_DS);
+	symlen = h_src->d_inode->i_op->readlink(h_src, (char __user *)sym,
+						PATH_MAX);
+	err = symlen;
+	set_fs(old_fs);
+
+	if (symlen > 0) {
+		sym[symlen] = 0;
+		err = vfsub_symlink(h_dir, h_path, sym);
+	}
+	__putname(sym);
+
+ out:
+	return err;
+}
+
+/* return with the lower dst inode is locked */
+static noinline_for_stack
+int cpup_entry(struct dentry *dentry, aufs_bindex_t bdst,
+	       aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+	       struct dentry *dst_parent)
+{
+	int err;
+	umode_t mode;
+	unsigned int mnt_flags;
+	unsigned char isdir;
+	const unsigned char do_dt = !!au_ftest_cpup(flags, DTIME);
+	struct au_dtime dt;
+	struct path h_path;
+	struct dentry *h_src, *h_dst, *h_parent;
+	struct inode *h_inode, *h_dir;
+	struct super_block *sb;
+
+	/* bsrc branch can be ro/rw. */
+	h_src = au_h_dptr(dentry, bsrc);
+	h_inode = h_src->d_inode;
+	AuDebugOn(h_inode != au_h_iptr(dentry->d_inode, bsrc));
+
+	/* try stopping to be referenced while we are creating */
+	h_dst = au_h_dptr(dentry, bdst);
+	h_parent = h_dst->d_parent; /* dir inode is locked */
+	h_dir = h_parent->d_inode;
+	IMustLock(h_dir);
+	AuDebugOn(h_parent != h_dst->d_parent);
+
+	sb = dentry->d_sb;
+	h_path.mnt = au_sbr_mnt(sb, bdst);
+	if (do_dt) {
+		h_path.dentry = h_parent;
+		au_dtime_store(&dt, dst_parent, &h_path);
+	}
+	h_path.dentry = h_dst;
+
+	isdir = 0;
+	mode = h_inode->i_mode;
+	switch (mode & S_IFMT) {
+	case S_IFREG:
+		/* try stopping to update while we are referencing */
+		IMustLock(h_inode);
+		err = vfsub_create(h_dir, &h_path, mode | S_IWUSR);
+		if (!err)
+			err = au_do_cpup_regular
+				(dentry, bdst, bsrc, len,
+				 au_h_iptr(dst_parent->d_inode, bdst), &h_path);
+		break;
+	case S_IFDIR:
+		isdir = 1;
+		err = vfsub_mkdir(h_dir, &h_path, mode);
+		if (!err) {
+			/*
+			 * strange behaviour from the users view,
+			 * particularry setattr case
+			 */
+			if (au_ibstart(dst_parent->d_inode) == bdst)
+				au_cpup_attr_nlink(dst_parent->d_inode,
+						   /*force*/1);
+			au_cpup_attr_nlink(dentry->d_inode, /*force*/1);
+		}
+		break;
+	case S_IFLNK:
+		err = au_do_cpup_symlink(&h_path, h_src, h_dir);
+		break;
+	case S_IFCHR:
+	case S_IFBLK:
+		AuDebugOn(!capable(CAP_MKNOD));
+		/*FALLTHROUGH*/
+	case S_IFIFO:
+	case S_IFSOCK:
+		err = vfsub_mknod(h_dir, &h_path, mode, h_inode->i_rdev);
+		break;
+	default:
+		AuIOErr("Unknown inode type 0%o\n", mode);
+		err = -EIO;
+	}
+
+	mnt_flags = au_mntflags(sb);
+	if (!au_opt_test(mnt_flags, UDBA_NONE)
+	    && !isdir
+	    && au_opt_test(mnt_flags, XINO)
+	    && h_inode->i_nlink == 1
+	    /* todo: unnecessary? */
+	    /* && dentry->d_inode->i_nlink == 1 */
+	    && bdst < bsrc
+	    && !au_ftest_cpup(flags, KEEPLINO))
+		au_xino_write(sb, bsrc, h_inode->i_ino, /*ino*/0);
+		/* ignore this error */
+
+	if (do_dt)
+		au_dtime_revert(&dt);
+	return err;
+}
+
+/*
+ * copyup the @dentry from @bsrc to @bdst.
+ * the caller must set the both of lower dentries.
+ * @len is for truncating when it is -1 copyup the entire file.
+ * in link/rename cases, @dst_parent may be different from the real one.
+ */
+static int au_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
+			  aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+			  struct dentry *dst_parent)
+{
+	int err, rerr;
+	aufs_bindex_t old_ibstart;
+	unsigned char isdir, plink;
+	struct au_dtime dt;
+	struct path h_path;
+	struct dentry *h_src, *h_dst, *h_parent;
+	struct inode *dst_inode, *h_dir, *inode;
+	struct super_block *sb;
+
+	AuDebugOn(bsrc <= bdst);
+
+	sb = dentry->d_sb;
+	h_path.mnt = au_sbr_mnt(sb, bdst);
+	h_dst = au_h_dptr(dentry, bdst);
+	h_parent = h_dst->d_parent; /* dir inode is locked */
+	h_dir = h_parent->d_inode;
+	IMustLock(h_dir);
+
+	h_src = au_h_dptr(dentry, bsrc);
+	inode = dentry->d_inode;
+
+	if (!dst_parent)
+		dst_parent = dget_parent(dentry);
+	else
+		dget(dst_parent);
+
+	plink = !!au_opt_test(au_mntflags(sb), PLINK);
+	dst_inode = au_h_iptr(inode, bdst);
+	if (dst_inode) {
+		if (unlikely(!plink)) {
+			err = -EIO;
+			AuIOErr("i%lu exists on a upper branch "
+				"but plink is disabled\n", inode->i_ino);
+			goto out;
+		}
+
+		if (dst_inode->i_nlink) {
+			const int do_dt = au_ftest_cpup(flags, DTIME);
+
+			h_src = au_plink_lkup(inode, bdst);
+			err = PTR_ERR(h_src);
+			if (IS_ERR(h_src))
+				goto out;
+			if (unlikely(!h_src->d_inode)) {
+				err = -EIO;
+				AuIOErr("i%lu exists on a upper branch "
+					"but plink is broken\n", inode->i_ino);
+				dput(h_src);
+				goto out;
+			}
+
+			if (do_dt) {
+				h_path.dentry = h_parent;
+				au_dtime_store(&dt, dst_parent, &h_path);
+			}
+			h_path.dentry = h_dst;
+			err = vfsub_link(h_src, h_dir, &h_path);
+			if (do_dt)
+				au_dtime_revert(&dt);
+			dput(h_src);
+			goto out;
+		} else
+			/* todo: cpup_wh_file? */
+			/* udba work */
+			au_update_brange(inode, 1);
+	}
+
+	old_ibstart = au_ibstart(inode);
+	err = cpup_entry(dentry, bdst, bsrc, len, flags, dst_parent);
+	if (unlikely(err))
+		goto out;
+	dst_inode = h_dst->d_inode;
+	mutex_lock_nested(&dst_inode->i_mutex, AuLsc_I_CHILD2);
+
+	err = cpup_iattr(dentry, bdst, h_src);
+	isdir = S_ISDIR(dst_inode->i_mode);
+	if (!err) {
+		if (bdst < old_ibstart)
+			au_set_ibstart(inode, bdst);
+		au_set_h_iptr(inode, bdst, au_igrab(dst_inode),
+			      au_hi_flags(inode, isdir));
+		mutex_unlock(&dst_inode->i_mutex);
+		if (!isdir
+		    && h_src->d_inode->i_nlink > 1
+		    && plink)
+			au_plink_append(inode, bdst, h_dst);
+		goto out; /* success */
+	}
+
+	/* revert */
+	h_path.dentry = h_parent;
+	mutex_unlock(&dst_inode->i_mutex);
+	au_dtime_store(&dt, dst_parent, &h_path);
+	h_path.dentry = h_dst;
+	if (!isdir)
+		rerr = vfsub_unlink(h_dir, &h_path, /*force*/0);
+	else
+		rerr = vfsub_rmdir(h_dir, &h_path);
+	au_dtime_revert(&dt);
+	if (rerr) {
+		AuIOErr("failed removing broken entry(%d, %d)\n", err, rerr);
+		err = -EIO;
+	}
+
+ out:
+	dput(dst_parent);
+	return err;
+}
+
+struct au_cpup_single_args {
+	int *errp;
+	struct dentry *dentry;
+	aufs_bindex_t bdst, bsrc;
+	loff_t len;
+	unsigned int flags;
+	struct dentry *dst_parent;
+};
+
+static void au_call_cpup_single(void *args)
+{
+	struct au_cpup_single_args *a = args;
+	*a->errp = au_cpup_single(a->dentry, a->bdst, a->bsrc, a->len,
+				  a->flags, a->dst_parent);
+}
+
+int au_sio_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
+		       aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+		       struct dentry *dst_parent)
+{
+	int err, wkq_err;
+	umode_t mode;
+	struct dentry *h_dentry;
+
+	h_dentry = au_h_dptr(dentry, bsrc);
+	mode = h_dentry->d_inode->i_mode & S_IFMT;
+	if ((mode != S_IFCHR && mode != S_IFBLK)
+	    || capable(CAP_MKNOD))
+		err = au_cpup_single(dentry, bdst, bsrc, len, flags,
+				     dst_parent);
+	else {
+		struct au_cpup_single_args args = {
+			.errp		= &err,
+			.dentry		= dentry,
+			.bdst		= bdst,
+			.bsrc		= bsrc,
+			.len		= len,
+			.flags		= flags,
+			.dst_parent	= dst_parent
+		};
+		wkq_err = au_wkq_wait(au_call_cpup_single, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	return err;
+}
+
+/*
+ * copyup the @dentry from the first active lower branch to @bdst,
+ * using au_cpup_single().
+ */
+static int au_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+			  unsigned int flags)
+{
+	int err;
+	aufs_bindex_t bsrc, bend;
+
+	bend = au_dbend(dentry);
+	for (bsrc = bdst + 1; bsrc <= bend; bsrc++)
+		if (au_h_dptr(dentry, bsrc))
+			break;
+
+	err = au_lkup_neg(dentry, bdst);
+	if (!err) {
+		err = au_cpup_single(dentry, bdst, bsrc, len, flags, NULL);
+		if (!err)
+			return 0; /* success */
+
+		/* revert */
+		au_set_h_dptr(dentry, bdst, NULL);
+		au_set_dbstart(dentry, bsrc);
+	}
+
+	return err;
+}
+
+struct au_cpup_simple_args {
+	int *errp;
+	struct dentry *dentry;
+	aufs_bindex_t bdst;
+	loff_t len;
+	unsigned int flags;
+};
+
+static void au_call_cpup_simple(void *args)
+{
+	struct au_cpup_simple_args *a = args;
+	*a->errp = au_cpup_simple(a->dentry, a->bdst, a->len, a->flags);
+}
+
+int au_sio_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+		       unsigned int flags)
+{
+	int err, wkq_err;
+	unsigned char do_sio;
+	struct dentry *parent;
+	struct inode *h_dir;
+
+	parent = dget_parent(dentry);
+	h_dir = au_h_iptr(parent->d_inode, bdst);
+	do_sio = !!au_test_h_perm_sio(h_dir, MAY_EXEC | MAY_WRITE);
+	if (!do_sio) {
+		/*
+		 * testing CAP_MKNOD is for generic fs,
+		 * but CAP_FSETID is for xfs only, currently.
+		 */
+		umode_t mode = dentry->d_inode->i_mode;
+		do_sio = (((mode & (S_IFCHR | S_IFBLK))
+			   && !capable(CAP_MKNOD))
+			  || ((mode & (S_ISUID | S_ISGID))
+			      && !capable(CAP_FSETID)));
+	}
+	if (!do_sio)
+		err = au_cpup_simple(dentry, bdst, len, flags);
+	else {
+		struct au_cpup_simple_args args = {
+			.errp		= &err,
+			.dentry		= dentry,
+			.bdst		= bdst,
+			.len		= len,
+			.flags		= flags
+		};
+		wkq_err = au_wkq_wait(au_call_cpup_simple, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	dput(parent);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * copyup the deleted file for writing.
+ */
+static int au_do_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst,
+			 struct dentry *wh_dentry, struct file *file,
+			 loff_t len)
+{
+	int err;
+	aufs_bindex_t bstart;
+	struct au_dinfo *dinfo;
+	struct dentry *h_d_dst, *h_d_start;
+
+	dinfo = au_di(dentry);
+	AuRwMustWriteLock(&dinfo->di_rwsem);
+
+	bstart = dinfo->di_bstart;
+	h_d_dst = dinfo->di_hdentry[0 + bdst].hd_dentry;
+	dinfo->di_bstart = bdst;
+	dinfo->di_hdentry[0 + bdst].hd_dentry = wh_dentry;
+	h_d_start = dinfo->di_hdentry[0 + bstart].hd_dentry;
+	if (file)
+		dinfo->di_hdentry[0 + bstart].hd_dentry
+			= au_h_fptr(file, au_fbstart(file))->f_dentry;
+	err = au_cpup_single(dentry, bdst, bstart, len, !AuCpup_DTIME,
+			     /*h_parent*/NULL);
+	if (!err && file) {
+		err = au_reopen_nondir(file);
+		dinfo->di_hdentry[0 + bstart].hd_dentry = h_d_start;
+	}
+	dinfo->di_hdentry[0 + bdst].hd_dentry = h_d_dst;
+	dinfo->di_bstart = bstart;
+
+	return err;
+}
+
+static int au_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+		      struct file *file)
+{
+	int err;
+	struct au_dtime dt;
+	struct dentry *parent, *h_parent, *wh_dentry;
+	struct au_branch *br;
+	struct path h_path;
+
+	br = au_sbr(dentry->d_sb, bdst);
+	parent = dget_parent(dentry);
+	h_parent = au_h_dptr(parent, bdst);
+	wh_dentry = au_whtmp_lkup(h_parent, br, &dentry->d_name);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry))
+		goto out;
+
+	h_path.dentry = h_parent;
+	h_path.mnt = br->br_mnt;
+	au_dtime_store(&dt, parent, &h_path);
+	err = au_do_cpup_wh(dentry, bdst, wh_dentry, file, len);
+	if (unlikely(err))
+		goto out_wh;
+
+	dget(wh_dentry);
+	h_path.dentry = wh_dentry;
+	err = vfsub_unlink(h_parent->d_inode, &h_path, /*force*/0);
+	if (unlikely(err)) {
+		AuIOErr("failed remove copied-up tmp file %.*s(%d)\n",
+			AuDLNPair(wh_dentry), err);
+		err = -EIO;
+	}
+	au_dtime_revert(&dt);
+	au_set_hi_wh(dentry->d_inode, bdst, wh_dentry);
+
+ out_wh:
+	dput(wh_dentry);
+ out:
+	dput(parent);
+	return err;
+}
+
+struct au_cpup_wh_args {
+	int *errp;
+	struct dentry *dentry;
+	aufs_bindex_t bdst;
+	loff_t len;
+	struct file *file;
+};
+
+static void au_call_cpup_wh(void *args)
+{
+	struct au_cpup_wh_args *a = args;
+	*a->errp = au_cpup_wh(a->dentry, a->bdst, a->len, a->file);
+}
+
+int au_sio_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+		   struct file *file)
+{
+	int err, wkq_err;
+	struct dentry *parent, *h_orph, *h_parent, *h_dentry;
+	struct inode *dir, *h_dir, *h_tmpdir, *h_inode;
+	struct au_wbr *wbr;
+
+	parent = dget_parent(dentry);
+	dir = parent->d_inode;
+	h_orph = NULL;
+	h_parent = NULL;
+	h_dir = au_igrab(au_h_iptr(dir, bdst));
+	h_tmpdir = h_dir;
+	if (!h_dir->i_nlink) {
+		wbr = au_sbr(dentry->d_sb, bdst)->br_wbr;
+		h_orph = wbr->wbr_orph;
+
+		h_parent = dget(au_h_dptr(parent, bdst));
+		au_set_h_dptr(parent, bdst, NULL);
+		au_set_h_dptr(parent, bdst, dget(h_orph));
+		h_tmpdir = h_orph->d_inode;
+		au_set_h_iptr(dir, bdst, NULL, 0);
+		au_set_h_iptr(dir, bdst, au_igrab(h_tmpdir), /*flags*/0);
+
+		/* this temporary unlock is safe */
+		if (file)
+			h_dentry = au_h_fptr(file, au_fbstart(file))->f_dentry;
+		else
+			h_dentry = au_h_dptr(dentry, au_dbstart(dentry));
+		h_inode = h_dentry->d_inode;
+		IMustLock(h_inode);
+		mutex_unlock(&h_inode->i_mutex);
+		mutex_lock_nested(&h_tmpdir->i_mutex, AuLsc_I_PARENT3);
+		mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+	}
+
+	if (!au_test_h_perm_sio(h_tmpdir, MAY_EXEC | MAY_WRITE))
+		err = au_cpup_wh(dentry, bdst, len, file);
+	else {
+		struct au_cpup_wh_args args = {
+			.errp	= &err,
+			.dentry	= dentry,
+			.bdst	= bdst,
+			.len	= len,
+			.file	= file
+		};
+		wkq_err = au_wkq_wait(au_call_cpup_wh, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	if (h_orph) {
+		mutex_unlock(&h_tmpdir->i_mutex);
+		au_set_h_iptr(dir, bdst, NULL, 0);
+		au_set_h_iptr(dir, bdst, au_igrab(h_dir), /*flags*/0);
+		au_set_h_dptr(parent, bdst, NULL);
+		au_set_h_dptr(parent, bdst, h_parent);
+	}
+	iput(h_dir);
+	dput(parent);
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * generic routine for both of copy-up and copy-down.
+ */
+/* cf. revalidate function in file.c */
+int au_cp_dirs(struct dentry *dentry, aufs_bindex_t bdst,
+	       int (*cp)(struct dentry *dentry, aufs_bindex_t bdst,
+			 struct dentry *h_parent, void *arg),
+	       void *arg)
+{
+	int err;
+	struct au_pin pin;
+	struct dentry *d, *parent, *h_parent, *real_parent;
+
+	err = 0;
+	parent = dget_parent(dentry);
+	if (IS_ROOT(parent))
+		goto out;
+
+	au_pin_init(&pin, dentry, bdst, AuLsc_DI_PARENT2, AuLsc_I_PARENT2,
+		    au_opt_udba(dentry->d_sb), AuPin_MNT_WRITE);
+
+	/* do not use au_dpage */
+	real_parent = parent;
+	while (1) {
+		dput(parent);
+		parent = dget_parent(dentry);
+		h_parent = au_h_dptr(parent, bdst);
+		if (h_parent)
+			goto out; /* success */
+
+		/* find top dir which is necessary to cpup */
+		do {
+			d = parent;
+			dput(parent);
+			parent = dget_parent(d);
+			di_read_lock_parent3(parent, !AuLock_IR);
+			h_parent = au_h_dptr(parent, bdst);
+			di_read_unlock(parent, !AuLock_IR);
+		} while (!h_parent);
+
+		if (d != real_parent)
+			di_write_lock_child3(d);
+
+		/* somebody else might create while we were sleeping */
+		if (!au_h_dptr(d, bdst) || !au_h_dptr(d, bdst)->d_inode) {
+			if (au_h_dptr(d, bdst))
+				au_update_dbstart(d);
+
+			au_pin_set_dentry(&pin, d);
+			err = au_do_pin(&pin);
+			if (!err) {
+				err = cp(d, bdst, h_parent, arg);
+				au_unpin(&pin);
+			}
+		}
+
+		if (d != real_parent)
+			di_write_unlock(d);
+		if (unlikely(err))
+			break;
+	}
+
+ out:
+	dput(parent);
+	return err;
+}
+
+static int au_cpup_dir(struct dentry *dentry, aufs_bindex_t bdst,
+		       struct dentry *h_parent __maybe_unused ,
+		       void *arg __maybe_unused)
+{
+	return au_sio_cpup_simple(dentry, bdst, -1, AuCpup_DTIME);
+}
+
+int au_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst)
+{
+	return au_cp_dirs(dentry, bdst, au_cpup_dir, NULL);
+}
+
+int au_test_and_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst)
+{
+	int err;
+	struct dentry *parent;
+	struct inode *dir;
+
+	parent = dget_parent(dentry);
+	dir = parent->d_inode;
+	err = 0;
+	if (au_h_iptr(dir, bdst))
+		goto out;
+
+	di_read_unlock(parent, AuLock_IR);
+	di_write_lock_parent(parent);
+	/* someone else might change our inode while we were sleeping */
+	if (!au_h_iptr(dir, bdst))
+		err = au_cpup_dirs(dentry, bdst);
+	di_downgrade_lock(parent, AuLock_IR);
+
+ out:
+	dput(parent);
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/cpup.h linux-2.6.31.4/fs/aufs/cpup.h
--- linux-2.6.31.4.orig/fs/aufs/cpup.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/cpup.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * copy-up/down functions
+ */
+
+#ifndef __AUFS_CPUP_H__
+#define __AUFS_CPUP_H__
+
+#ifdef __KERNEL__
+
+#include <linux/path.h>
+#include <linux/time.h>
+#include <linux/aufs_type.h>
+
+struct inode;
+struct file;
+
+void au_cpup_attr_flags(struct inode *dst, struct inode *src);
+void au_cpup_attr_timesizes(struct inode *inode);
+void au_cpup_attr_nlink(struct inode *inode, int force);
+void au_cpup_attr_changeable(struct inode *inode);
+void au_cpup_igen(struct inode *inode, struct inode *h_inode);
+void au_cpup_attr_all(struct inode *inode, int force);
+
+/* ---------------------------------------------------------------------- */
+
+/* cpup flags */
+#define AuCpup_DTIME	1		/* do dtime_store/revert */
+#define AuCpup_KEEPLINO	(1 << 1)	/* do not clear the lower xino,
+					   for link(2) */
+#define au_ftest_cpup(flags, name)	((flags) & AuCpup_##name)
+#define au_fset_cpup(flags, name)	{ (flags) |= AuCpup_##name; }
+#define au_fclr_cpup(flags, name)	{ (flags) &= ~AuCpup_##name; }
+
+int au_copy_file(struct file *dst, struct file *src, loff_t len);
+int au_sio_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
+		       aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+		       struct dentry *dst_parent);
+int au_sio_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+		       unsigned int flags);
+int au_sio_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+		   struct file *file);
+
+int au_cp_dirs(struct dentry *dentry, aufs_bindex_t bdst,
+	       int (*cp)(struct dentry *dentry, aufs_bindex_t bdst,
+			 struct dentry *h_parent, void *arg),
+	       void *arg);
+int au_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst);
+int au_test_and_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst);
+
+/* ---------------------------------------------------------------------- */
+
+/* keep timestamps when copyup */
+struct au_dtime {
+	struct dentry *dt_dentry;
+	struct path dt_h_path;
+	struct timespec dt_atime, dt_mtime;
+};
+void au_dtime_store(struct au_dtime *dt, struct dentry *dentry,
+		    struct path *h_path);
+void au_dtime_revert(struct au_dtime *dt);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_CPUP_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/dbgaufs.c linux-2.6.31.4/fs/aufs/dbgaufs.c
--- linux-2.6.31.4.orig/fs/aufs/dbgaufs.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/dbgaufs.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,331 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * debugfs interface
+ */
+
+#include <linux/debugfs.h>
+#include "aufs.h"
+
+#ifndef CONFIG_SYSFS
+#error DEBUG_FS depends upon SYSFS
+#endif
+
+static struct dentry *dbgaufs;
+static const mode_t dbgaufs_mode = S_IRUSR | S_IRGRP | S_IROTH;
+
+/* 20 is max digits length of ulong 64 */
+struct dbgaufs_arg {
+	int n;
+	char a[20 * 4];
+};
+
+/*
+ * common function for all XINO files
+ */
+static int dbgaufs_xi_release(struct inode *inode __maybe_unused,
+			      struct file *file)
+{
+	kfree(file->private_data);
+	return 0;
+}
+
+static int dbgaufs_xi_open(struct file *xf, struct file *file, int do_fcnt)
+{
+	int err;
+	struct kstat st;
+	struct dbgaufs_arg *p;
+
+	err = -ENOMEM;
+	p = kmalloc(sizeof(*p), GFP_NOFS);
+	if (unlikely(!p))
+		goto out;
+
+	err = 0;
+	p->n = 0;
+	file->private_data = p;
+	if (!xf)
+		goto out;
+
+	err = vfs_getattr(xf->f_vfsmnt, xf->f_dentry, &st);
+	if (!err) {
+		if (do_fcnt)
+			p->n = snprintf
+				(p->a, sizeof(p->a), "%ld, %llux%lu %lld\n",
+				 (long)file_count(xf), st.blocks, st.blksize,
+				 (long long)st.size);
+		else
+			p->n = snprintf(p->a, sizeof(p->a), "%llux%lu %lld\n",
+					st.blocks, st.blksize,
+					(long long)st.size);
+		AuDebugOn(p->n >= sizeof(p->a));
+	} else {
+		p->n = snprintf(p->a, sizeof(p->a), "err %d\n", err);
+		err = 0;
+	}
+
+ out:
+	return err;
+
+}
+
+static ssize_t dbgaufs_xi_read(struct file *file, char __user *buf,
+			       size_t count, loff_t *ppos)
+{
+	struct dbgaufs_arg *p;
+
+	p = file->private_data;
+	return simple_read_from_buffer(buf, count, ppos, p->a, p->n);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int dbgaufs_xib_open(struct inode *inode, struct file *file)
+{
+	int err;
+	struct au_sbinfo *sbinfo;
+	struct super_block *sb;
+
+	sbinfo = inode->i_private;
+	sb = sbinfo->si_sb;
+	si_noflush_read_lock(sb);
+	err = dbgaufs_xi_open(sbinfo->si_xib, file, /*do_fcnt*/0);
+	si_read_unlock(sb);
+	return err;
+}
+
+static const struct file_operations dbgaufs_xib_fop = {
+	.open		= dbgaufs_xib_open,
+	.release	= dbgaufs_xi_release,
+	.read		= dbgaufs_xi_read
+};
+
+/* ---------------------------------------------------------------------- */
+
+#define DbgaufsXi_PREFIX "xi"
+
+static int dbgaufs_xino_open(struct inode *inode, struct file *file)
+{
+	int err;
+	long l;
+	struct au_sbinfo *sbinfo;
+	struct super_block *sb;
+	struct file *xf;
+	struct qstr *name;
+
+	err = -ENOENT;
+	xf = NULL;
+	name = &file->f_dentry->d_name;
+	if (unlikely(name->len < sizeof(DbgaufsXi_PREFIX)
+		     || memcmp(name->name, DbgaufsXi_PREFIX,
+			       sizeof(DbgaufsXi_PREFIX) - 1)))
+		goto out;
+	err = strict_strtol(name->name + sizeof(DbgaufsXi_PREFIX) - 1, 10, &l);
+	if (unlikely(err))
+		goto out;
+
+	sbinfo = inode->i_private;
+	sb = sbinfo->si_sb;
+	si_noflush_read_lock(sb);
+	if (l <= au_sbend(sb)) {
+		xf = au_sbr(sb, (aufs_bindex_t)l)->br_xino.xi_file;
+		err = dbgaufs_xi_open(xf, file, /*do_fcnt*/1);
+	} else
+		err = -ENOENT;
+	si_read_unlock(sb);
+
+ out:
+	return err;
+}
+
+static const struct file_operations dbgaufs_xino_fop = {
+	.open		= dbgaufs_xino_open,
+	.release	= dbgaufs_xi_release,
+	.read		= dbgaufs_xi_read
+};
+
+void dbgaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
+{
+	aufs_bindex_t bend;
+	struct au_branch *br;
+	struct au_xino_file *xi;
+
+	if (!au_sbi(sb)->si_dbgaufs)
+		return;
+
+	bend = au_sbend(sb);
+	for (; bindex <= bend; bindex++) {
+		br = au_sbr(sb, bindex);
+		xi = &br->br_xino;
+		if (xi->xi_dbgaufs) {
+			debugfs_remove(xi->xi_dbgaufs);
+			xi->xi_dbgaufs = NULL;
+		}
+	}
+}
+
+void dbgaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
+{
+	struct au_sbinfo *sbinfo;
+	struct dentry *parent;
+	struct au_branch *br;
+	struct au_xino_file *xi;
+	aufs_bindex_t bend;
+	char name[sizeof(DbgaufsXi_PREFIX) + 5]; /* "xi" bindex NULL */
+
+	sbinfo = au_sbi(sb);
+	parent = sbinfo->si_dbgaufs;
+	if (!parent)
+		return;
+
+	bend = au_sbend(sb);
+	for (; bindex <= bend; bindex++) {
+		snprintf(name, sizeof(name), DbgaufsXi_PREFIX "%d", bindex);
+		br = au_sbr(sb, bindex);
+		xi = &br->br_xino;
+		AuDebugOn(xi->xi_dbgaufs);
+		xi->xi_dbgaufs = debugfs_create_file(name, dbgaufs_mode, parent,
+						     sbinfo, &dbgaufs_xino_fop);
+		/* ignore an error */
+		if (unlikely(!xi->xi_dbgaufs))
+			AuWarn1("failed %s under debugfs\n", name);
+	}
+}
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_EXPORT
+static int dbgaufs_xigen_open(struct inode *inode, struct file *file)
+{
+	int err;
+	struct au_sbinfo *sbinfo;
+	struct super_block *sb;
+
+	sbinfo = inode->i_private;
+	sb = sbinfo->si_sb;
+	si_noflush_read_lock(sb);
+	err = dbgaufs_xi_open(sbinfo->si_xigen, file, /*do_fcnt*/0);
+	si_read_unlock(sb);
+	return err;
+}
+
+static const struct file_operations dbgaufs_xigen_fop = {
+	.open		= dbgaufs_xigen_open,
+	.release	= dbgaufs_xi_release,
+	.read		= dbgaufs_xi_read
+};
+
+static int dbgaufs_xigen_init(struct au_sbinfo *sbinfo)
+{
+	int err;
+
+	/*
+	 * This function is a dynamic '__init' fucntion actually,
+	 * so the tiny check for si_rwsem is unnecessary.
+	 */
+	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
+
+	err = -EIO;
+	sbinfo->si_dbgaufs_xigen = debugfs_create_file
+		("xigen", dbgaufs_mode, sbinfo->si_dbgaufs, sbinfo,
+		 &dbgaufs_xigen_fop);
+	if (sbinfo->si_dbgaufs_xigen)
+		err = 0;
+
+	return err;
+}
+#else
+static int dbgaufs_xigen_init(struct au_sbinfo *sbinfo)
+{
+	return 0;
+}
+#endif /* CONFIG_AUFS_EXPORT */
+
+/* ---------------------------------------------------------------------- */
+
+void dbgaufs_si_fin(struct au_sbinfo *sbinfo)
+{
+	/*
+	 * This function is a dynamic '__init' fucntion actually,
+	 * so the tiny check for si_rwsem is unnecessary.
+	 */
+	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
+
+	debugfs_remove_recursive(sbinfo->si_dbgaufs);
+	sbinfo->si_dbgaufs = NULL;
+	kobject_put(&sbinfo->si_kobj);
+}
+
+int dbgaufs_si_init(struct au_sbinfo *sbinfo)
+{
+	int err;
+	char name[SysaufsSiNameLen];
+
+	/*
+	 * This function is a dynamic '__init' fucntion actually,
+	 * so the tiny check for si_rwsem is unnecessary.
+	 */
+	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
+
+	err = -ENOENT;
+	if (!dbgaufs) {
+		AuErr1("/debug/aufs is uninitialized\n");
+		goto out;
+	}
+
+	err = -EIO;
+	sysaufs_name(sbinfo, name);
+	sbinfo->si_dbgaufs = debugfs_create_dir(name, dbgaufs);
+	if (unlikely(!sbinfo->si_dbgaufs))
+		goto out;
+	kobject_get(&sbinfo->si_kobj);
+
+	sbinfo->si_dbgaufs_xib = debugfs_create_file
+		("xib", dbgaufs_mode, sbinfo->si_dbgaufs, sbinfo,
+		 &dbgaufs_xib_fop);
+	if (unlikely(!sbinfo->si_dbgaufs_xib))
+		goto out_dir;
+
+	err = dbgaufs_xigen_init(sbinfo);
+	if (!err)
+		goto out; /* success */
+
+ out_dir:
+	dbgaufs_si_fin(sbinfo);
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void dbgaufs_fin(void)
+{
+	debugfs_remove(dbgaufs);
+}
+
+int __init dbgaufs_init(void)
+{
+	int err;
+
+	err = -EIO;
+	dbgaufs = debugfs_create_dir(AUFS_NAME, NULL);
+	if (dbgaufs)
+		err = 0;
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/dbgaufs.h linux-2.6.31.4/fs/aufs/dbgaufs.h
--- linux-2.6.31.4.orig/fs/aufs/dbgaufs.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/dbgaufs.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * debugfs interface
+ */
+
+#ifndef __DBGAUFS_H__
+#define __DBGAUFS_H__
+
+#ifdef __KERNEL__
+
+#include <linux/init.h>
+#include <linux/aufs_type.h>
+
+struct super_block;
+struct au_sbinfo;
+
+#ifdef CONFIG_DEBUG_FS
+/* dbgaufs.c */
+void dbgaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex);
+void dbgaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex);
+void dbgaufs_si_fin(struct au_sbinfo *sbinfo);
+int dbgaufs_si_init(struct au_sbinfo *sbinfo);
+void dbgaufs_fin(void);
+int __init dbgaufs_init(void);
+
+#else
+
+static inline
+void dbgaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
+{
+	/* empty */
+}
+
+static inline
+void dbgaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
+{
+	/* empty */
+}
+
+static inline
+void dbgaufs_si_fin(struct au_sbinfo *sbinfo)
+{
+	/* empty */
+}
+
+static inline
+int dbgaufs_si_init(struct au_sbinfo *sbinfo)
+{
+	return 0;
+}
+
+#define dbgaufs_fin()	do {} while (0)
+
+static inline
+int __init dbgaufs_init(void)
+{
+	return 0;
+}
+#endif /* CONFIG_DEBUG_FS */
+
+#endif /* __KERNEL__ */
+#endif /* __DBGAUFS_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/dcsub.c linux-2.6.31.4/fs/aufs/dcsub.c
--- linux-2.6.31.4.orig/fs/aufs/dcsub.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/dcsub.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,223 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sub-routines for dentry cache
+ */
+
+#include "aufs.h"
+
+static void au_dpage_free(struct au_dpage *dpage)
+{
+	int i;
+	struct dentry **p;
+
+	p = dpage->dentries;
+	for (i = 0; i < dpage->ndentry; i++)
+		dput(*p++);
+	free_page((unsigned long)dpage->dentries);
+}
+
+int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp)
+{
+	int err;
+	void *p;
+
+	err = -ENOMEM;
+	dpages->dpages = kmalloc(sizeof(*dpages->dpages), gfp);
+	if (unlikely(!dpages->dpages))
+		goto out;
+
+	p = (void *)__get_free_page(gfp);
+	if (unlikely(!p))
+		goto out_dpages;
+
+	dpages->dpages[0].ndentry = 0;
+	dpages->dpages[0].dentries = p;
+	dpages->ndpage = 1;
+	return 0; /* success */
+
+ out_dpages:
+	kfree(dpages->dpages);
+ out:
+	return err;
+}
+
+void au_dpages_free(struct au_dcsub_pages *dpages)
+{
+	int i;
+	struct au_dpage *p;
+
+	p = dpages->dpages;
+	for (i = 0; i < dpages->ndpage; i++)
+		au_dpage_free(p++);
+	kfree(dpages->dpages);
+}
+
+static int au_dpages_append(struct au_dcsub_pages *dpages,
+			    struct dentry *dentry, gfp_t gfp)
+{
+	int err, sz;
+	struct au_dpage *dpage;
+	void *p;
+
+	dpage = dpages->dpages + dpages->ndpage - 1;
+	sz = PAGE_SIZE / sizeof(dentry);
+	if (unlikely(dpage->ndentry >= sz)) {
+		AuLabel(new dpage);
+		err = -ENOMEM;
+		sz = dpages->ndpage * sizeof(*dpages->dpages);
+		p = au_kzrealloc(dpages->dpages, sz,
+				 sz + sizeof(*dpages->dpages), gfp);
+		if (unlikely(!p))
+			goto out;
+
+		dpages->dpages = p;
+		dpage = dpages->dpages + dpages->ndpage;
+		p = (void *)__get_free_page(gfp);
+		if (unlikely(!p))
+			goto out;
+
+		dpage->ndentry = 0;
+		dpage->dentries = p;
+		dpages->ndpage++;
+	}
+
+	dpage->dentries[dpage->ndentry++] = dget(dentry);
+	return 0; /* success */
+
+ out:
+	return err;
+}
+
+int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
+		   au_dpages_test test, void *arg)
+{
+	int err;
+	struct dentry *this_parent = root;
+	struct list_head *next;
+	struct super_block *sb = root->d_sb;
+
+	err = 0;
+	spin_lock(&dcache_lock);
+ repeat:
+	next = this_parent->d_subdirs.next;
+ resume:
+	if (this_parent->d_sb == sb
+	    && !IS_ROOT(this_parent)
+	    && atomic_read(&this_parent->d_count)
+	    && this_parent->d_inode
+	    && (!test || test(this_parent, arg))) {
+		err = au_dpages_append(dpages, this_parent, GFP_ATOMIC);
+		if (unlikely(err))
+			goto out;
+	}
+
+	while (next != &this_parent->d_subdirs) {
+		struct list_head *tmp = next;
+		struct dentry *dentry = list_entry(tmp, struct dentry,
+						   d_u.d_child);
+		next = tmp->next;
+		if (/*d_unhashed(dentry) || */!dentry->d_inode)
+			continue;
+		if (!list_empty(&dentry->d_subdirs)) {
+			this_parent = dentry;
+			goto repeat;
+		}
+		if (dentry->d_sb == sb
+		    && atomic_read(&dentry->d_count)
+		    && (!test || test(dentry, arg))) {
+			err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+			if (unlikely(err))
+				goto out;
+		}
+	}
+
+	if (this_parent != root) {
+		next = this_parent->d_u.d_child.next;
+		this_parent = this_parent->d_parent; /* dcache_lock is locked */
+		goto resume;
+	}
+ out:
+	spin_unlock(&dcache_lock);
+	return err;
+}
+
+int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
+		       int do_include, au_dpages_test test, void *arg)
+{
+	int err;
+
+	err = 0;
+	spin_lock(&dcache_lock);
+	if (do_include && (!test || test(dentry, arg))) {
+		err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+		if (unlikely(err))
+			goto out;
+	}
+	while (!IS_ROOT(dentry)) {
+		dentry = dentry->d_parent; /* dcache_lock is locked */
+		if (!test || test(dentry, arg)) {
+			err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+			if (unlikely(err))
+				break;
+		}
+	}
+
+ out:
+	spin_unlock(&dcache_lock);
+
+	return err;
+}
+
+struct dentry *au_test_subdir(struct dentry *d1, struct dentry *d2)
+{
+	struct dentry *trap, **dentries;
+	int err, i, j;
+	struct au_dcsub_pages dpages;
+	struct au_dpage *dpage;
+
+	trap = ERR_PTR(-ENOMEM);
+	err = au_dpages_init(&dpages, GFP_NOFS);
+	if (unlikely(err))
+		goto out;
+	err = au_dcsub_pages_rev(&dpages, d1, /*do_include*/1, NULL, NULL);
+	if (unlikely(err))
+		goto out_dpages;
+
+	trap = d1;
+	for (i = 0; !err && i < dpages.ndpage; i++) {
+		dpage = dpages.dpages + i;
+		dentries = dpage->dentries;
+		for (j = 0; !err && j < dpage->ndentry; j++) {
+			struct dentry *d;
+
+			d = dentries[j];
+			err = (d == d2);
+			if (!err)
+				trap = d;
+		}
+	}
+	if (!err)
+		trap = NULL;
+
+ out_dpages:
+	au_dpages_free(&dpages);
+ out:
+	return trap;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/dcsub.h linux-2.6.31.4/fs/aufs/dcsub.h
--- linux-2.6.31.4.orig/fs/aufs/dcsub.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/dcsub.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sub-routines for dentry cache
+ */
+
+#ifndef __AUFS_DCSUB_H__
+#define __AUFS_DCSUB_H__
+
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+
+struct dentry;
+
+struct au_dpage {
+	int ndentry;
+	struct dentry **dentries;
+};
+
+struct au_dcsub_pages {
+	int ndpage;
+	struct au_dpage *dpages;
+};
+
+/* ---------------------------------------------------------------------- */
+
+int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp);
+void au_dpages_free(struct au_dcsub_pages *dpages);
+typedef int (*au_dpages_test)(struct dentry *dentry, void *arg);
+int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
+		   au_dpages_test test, void *arg);
+int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
+		       int do_include, au_dpages_test test, void *arg);
+struct dentry *au_test_subdir(struct dentry *d1, struct dentry *d2);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_DCSUB_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/debug.c linux-2.6.31.4/fs/aufs/debug.c
--- linux-2.6.31.4.orig/fs/aufs/debug.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/debug.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,427 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * debug print functions
+ */
+
+#include <linux/module.h>
+#include <linux/vt_kern.h>
+#include "aufs.h"
+
+int aufs_debug;
+MODULE_PARM_DESC(debug, "debug print");
+module_param_named(debug, aufs_debug, int, S_IRUGO | S_IWUSR | S_IWGRP);
+
+char *au_plevel = KERN_DEBUG;
+#define dpri(fmt, arg...) do { \
+	if (au_debug_test()) \
+		printk("%s" fmt, au_plevel, ##arg); \
+} while (0)
+
+/* ---------------------------------------------------------------------- */
+
+void au_dpri_whlist(struct au_nhash *whlist)
+{
+	unsigned long ul, n;
+	struct hlist_head *head;
+	struct au_vdir_wh *tpos;
+	struct hlist_node *pos;
+
+	n = whlist->nh_num;
+	head = whlist->nh_head;
+	for (ul = 0; ul < n; ul++) {
+		hlist_for_each_entry(tpos, pos, head, wh_hash)
+			dpri("b%d, %.*s, %d\n",
+			     tpos->wh_bindex,
+			     tpos->wh_str.len, tpos->wh_str.name,
+			     tpos->wh_str.len);
+		head++;
+	}
+}
+
+void au_dpri_vdir(struct au_vdir *vdir)
+{
+	unsigned long ul;
+	union au_vdir_deblk_p p;
+	unsigned char *o;
+
+	if (!vdir || IS_ERR(vdir)) {
+		dpri("err %ld\n", PTR_ERR(vdir));
+		return;
+	}
+
+	dpri("deblk %u, nblk %lu, deblk %p, last{%lu, %p}, ver %lu\n",
+	     vdir->vd_deblk_sz, vdir->vd_nblk, vdir->vd_deblk,
+	     vdir->vd_last.ul, vdir->vd_last.p.deblk, vdir->vd_version);
+	for (ul = 0; ul < vdir->vd_nblk; ul++) {
+		p.deblk = vdir->vd_deblk[ul];
+		o = p.deblk;
+		dpri("[%lu]: %p\n", ul, o);
+	}
+}
+
+static int do_pri_inode(aufs_bindex_t bindex, struct inode *inode,
+			struct dentry *wh)
+{
+	char *n = NULL;
+	int l = 0;
+
+	if (!inode || IS_ERR(inode)) {
+		dpri("i%d: err %ld\n", bindex, PTR_ERR(inode));
+		return -1;
+	}
+
+	/* the type of i_blocks depends upon CONFIG_LSF */
+	BUILD_BUG_ON(sizeof(inode->i_blocks) != sizeof(unsigned long)
+		     && sizeof(inode->i_blocks) != sizeof(u64));
+	if (wh) {
+		n = (void *)wh->d_name.name;
+		l = wh->d_name.len;
+	}
+
+	dpri("i%d: i%lu, %s, cnt %d, nl %u, 0%o, sz %llu, blk %llu,"
+	     " ct %lld, np %lu, st 0x%lx, f 0x%x, g %x%s%.*s\n",
+	     bindex,
+	     inode->i_ino, inode->i_sb ? au_sbtype(inode->i_sb) : "??",
+	     atomic_read(&inode->i_count), inode->i_nlink, inode->i_mode,
+	     i_size_read(inode), (unsigned long long)inode->i_blocks,
+	     (long long)timespec_to_ns(&inode->i_ctime) & 0x0ffff,
+	     inode->i_mapping ? inode->i_mapping->nrpages : 0,
+	     inode->i_state, inode->i_flags, inode->i_generation,
+	     l ? ", wh " : "", l, n);
+	return 0;
+}
+
+void au_dpri_inode(struct inode *inode)
+{
+	struct au_iinfo *iinfo;
+	aufs_bindex_t bindex;
+	int err;
+
+	err = do_pri_inode(-1, inode, NULL);
+	if (err || !au_test_aufs(inode->i_sb))
+		return;
+
+	iinfo = au_ii(inode);
+	if (!iinfo)
+		return;
+	dpri("i-1: bstart %d, bend %d, gen %d\n",
+	     iinfo->ii_bstart, iinfo->ii_bend, au_iigen(inode));
+	if (iinfo->ii_bstart < 0)
+		return;
+	for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend; bindex++)
+		do_pri_inode(bindex, iinfo->ii_hinode[0 + bindex].hi_inode,
+			     iinfo->ii_hinode[0 + bindex].hi_whdentry);
+}
+
+static int do_pri_dentry(aufs_bindex_t bindex, struct dentry *dentry)
+{
+	struct dentry *wh = NULL;
+
+	if (!dentry || IS_ERR(dentry)) {
+		dpri("d%d: err %ld\n", bindex, PTR_ERR(dentry));
+		return -1;
+	}
+	/* do not call dget_parent() here */
+	dpri("d%d: %.*s?/%.*s, %s, cnt %d, flags 0x%x\n",
+	     bindex,
+	     AuDLNPair(dentry->d_parent), AuDLNPair(dentry),
+	     dentry->d_sb ? au_sbtype(dentry->d_sb) : "??",
+	     atomic_read(&dentry->d_count), dentry->d_flags);
+	if (bindex >= 0 && dentry->d_inode && au_test_aufs(dentry->d_sb)) {
+		struct au_iinfo *iinfo = au_ii(dentry->d_inode);
+		if (iinfo)
+			wh = iinfo->ii_hinode[0 + bindex].hi_whdentry;
+	}
+	do_pri_inode(bindex, dentry->d_inode, wh);
+	return 0;
+}
+
+void au_dpri_dentry(struct dentry *dentry)
+{
+	struct au_dinfo *dinfo;
+	aufs_bindex_t bindex;
+	int err;
+
+	err = do_pri_dentry(-1, dentry);
+	if (err || !au_test_aufs(dentry->d_sb))
+		return;
+
+	dinfo = au_di(dentry);
+	if (!dinfo)
+		return;
+	dpri("d-1: bstart %d, bend %d, bwh %d, bdiropq %d, gen %d\n",
+	     dinfo->di_bstart, dinfo->di_bend,
+	     dinfo->di_bwh, dinfo->di_bdiropq, au_digen(dentry));
+	if (dinfo->di_bstart < 0)
+		return;
+	for (bindex = dinfo->di_bstart; bindex <= dinfo->di_bend; bindex++)
+		do_pri_dentry(bindex, dinfo->di_hdentry[0 + bindex].hd_dentry);
+}
+
+static int do_pri_file(aufs_bindex_t bindex, struct file *file)
+{
+	char a[32];
+
+	if (!file || IS_ERR(file)) {
+		dpri("f%d: err %ld\n", bindex, PTR_ERR(file));
+		return -1;
+	}
+	a[0] = 0;
+	if (bindex < 0
+	    && file->f_dentry
+	    && au_test_aufs(file->f_dentry->d_sb)
+	    && au_fi(file))
+		snprintf(a, sizeof(a), ", mmapped %d", au_test_mmapped(file));
+	dpri("f%d: mode 0x%x, flags 0%o, cnt %ld, pos %llu%s\n",
+	     bindex, file->f_mode, file->f_flags, (long)file_count(file),
+	     file->f_pos, a);
+	if (file->f_dentry)
+		do_pri_dentry(bindex, file->f_dentry);
+	return 0;
+}
+
+void au_dpri_file(struct file *file)
+{
+	struct au_finfo *finfo;
+	aufs_bindex_t bindex;
+	int err;
+
+	err = do_pri_file(-1, file);
+	if (err || !file->f_dentry || !au_test_aufs(file->f_dentry->d_sb))
+		return;
+
+	finfo = au_fi(file);
+	if (!finfo)
+		return;
+	if (finfo->fi_bstart < 0)
+		return;
+	for (bindex = finfo->fi_bstart; bindex <= finfo->fi_bend; bindex++) {
+		struct au_hfile *hf;
+
+		hf = finfo->fi_hfile + bindex;
+		do_pri_file(bindex, hf ? hf->hf_file : NULL);
+	}
+}
+
+static int do_pri_br(aufs_bindex_t bindex, struct au_branch *br)
+{
+	struct vfsmount *mnt;
+	struct super_block *sb;
+
+	if (!br || IS_ERR(br))
+		goto out;
+	mnt = br->br_mnt;
+	if (!mnt || IS_ERR(mnt))
+		goto out;
+	sb = mnt->mnt_sb;
+	if (!sb || IS_ERR(sb))
+		goto out;
+
+	dpri("s%d: {perm 0x%x, cnt %d, wbr %p}, "
+	     "%s, dev 0x%02x%02x, flags 0x%lx, cnt(BIAS) %d, active %d, "
+	     "xino %d\n",
+	     bindex, br->br_perm, atomic_read(&br->br_count), br->br_wbr,
+	     au_sbtype(sb), MAJOR(sb->s_dev), MINOR(sb->s_dev),
+	     sb->s_flags, sb->s_count - S_BIAS,
+	     atomic_read(&sb->s_active), !!br->br_xino.xi_file);
+	return 0;
+
+ out:
+	dpri("s%d: err %ld\n", bindex, PTR_ERR(br));
+	return -1;
+}
+
+void au_dpri_sb(struct super_block *sb)
+{
+	struct au_sbinfo *sbinfo;
+	aufs_bindex_t bindex;
+	int err;
+	/* to reuduce stack size */
+	struct {
+		struct vfsmount mnt;
+		struct au_branch fake;
+	} *a;
+
+	/* this function can be called from magic sysrq */
+	a = kzalloc(sizeof(*a), GFP_ATOMIC);
+	if (unlikely(!a)) {
+		dpri("no memory\n");
+		return;
+	}
+
+	a->mnt.mnt_sb = sb;
+	a->fake.br_perm = 0;
+	a->fake.br_mnt = &a->mnt;
+	a->fake.br_xino.xi_file = NULL;
+	atomic_set(&a->fake.br_count, 0);
+	smp_mb(); /* atomic_set */
+	err = do_pri_br(-1, &a->fake);
+	kfree(a);
+	dpri("dev 0x%x\n", sb->s_dev);
+	if (err || !au_test_aufs(sb))
+		return;
+
+	sbinfo = au_sbi(sb);
+	if (!sbinfo)
+		return;
+	dpri("nw %d, gen %u, kobj %d\n",
+	     atomic_read(&sbinfo->si_nowait.nw_len), sbinfo->si_generation,
+	     atomic_read(&sbinfo->si_kobj.kref.refcount));
+	for (bindex = 0; bindex <= sbinfo->si_bend; bindex++)
+		do_pri_br(bindex, sbinfo->si_branch[0 + bindex]);
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_dbg_sleep_jiffy(int jiffy)
+{
+	while (jiffy)
+		jiffy = schedule_timeout_uninterruptible(jiffy);
+}
+
+void au_dbg_iattr(struct iattr *ia)
+{
+#define AuBit(name)	if (ia->ia_valid & ATTR_ ## name) \
+				dpri(#name "\n")
+	AuBit(MODE);
+	AuBit(UID);
+	AuBit(GID);
+	AuBit(SIZE);
+	AuBit(ATIME);
+	AuBit(MTIME);
+	AuBit(CTIME);
+	AuBit(ATIME_SET);
+	AuBit(MTIME_SET);
+	AuBit(FORCE);
+	AuBit(ATTR_FLAG);
+	AuBit(KILL_SUID);
+	AuBit(KILL_SGID);
+	AuBit(FILE);
+	AuBit(KILL_PRIV);
+	AuBit(OPEN);
+	AuBit(TIMES_SET);
+#undef	AuBit
+	dpri("ia_file %p\n", ia->ia_file);
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_dbg_verify_dir_parent(struct dentry *dentry, unsigned int sigen)
+{
+	struct dentry *parent;
+
+	parent = dget_parent(dentry);
+	AuDebugOn(!S_ISDIR(dentry->d_inode->i_mode)
+		  || IS_ROOT(dentry)
+		  || au_digen(parent) != sigen);
+	dput(parent);
+}
+
+void au_dbg_verify_nondir_parent(struct dentry *dentry, unsigned int sigen)
+{
+	struct dentry *parent;
+
+	parent = dget_parent(dentry);
+	AuDebugOn(S_ISDIR(dentry->d_inode->i_mode)
+		  || au_digen(parent) != sigen);
+	dput(parent);
+}
+
+void au_dbg_verify_gen(struct dentry *parent, unsigned int sigen)
+{
+	int err, i, j;
+	struct au_dcsub_pages dpages;
+	struct au_dpage *dpage;
+	struct dentry **dentries;
+
+	err = au_dpages_init(&dpages, GFP_NOFS);
+	AuDebugOn(err);
+	err = au_dcsub_pages_rev(&dpages, parent, /*do_include*/1, NULL, NULL);
+	AuDebugOn(err);
+	for (i = dpages.ndpage - 1; !err && i >= 0; i--) {
+		dpage = dpages.dpages + i;
+		dentries = dpage->dentries;
+		for (j = dpage->ndentry - 1; !err && j >= 0; j--)
+			AuDebugOn(au_digen(dentries[j]) != sigen);
+	}
+	au_dpages_free(&dpages);
+}
+
+void au_dbg_verify_hf(struct au_finfo *finfo)
+{
+	struct au_hfile *hf;
+	aufs_bindex_t bend, bindex;
+
+	if (finfo->fi_bstart >= 0) {
+		bend = finfo->fi_bend;
+		for (bindex = finfo->fi_bstart; bindex <= bend; bindex++) {
+			hf = finfo->fi_hfile + bindex;
+			AuDebugOn(hf->hf_file || hf->hf_br);
+		}
+	}
+}
+
+void au_dbg_verify_kthread(void)
+{
+	if (au_test_wkq(current)) {
+		au_dbg_blocked();
+		BUG();
+	}
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_debug_sbinfo_init(struct au_sbinfo *sbinfo __maybe_unused)
+{
+#ifdef AuForceNoPlink
+	au_opt_clr(sbinfo->si_mntflags, PLINK);
+#endif
+#ifdef AuForceNoXino
+	au_opt_clr(sbinfo->si_mntflags, XINO);
+#endif
+#ifdef AuForceNoRefrof
+	au_opt_clr(sbinfo->si_mntflags, REFROF);
+#endif
+#ifdef AuForceHinotify
+	au_opt_set_udba(sbinfo->si_mntflags, UDBA_HINOTIFY);
+#endif
+}
+
+int __init au_debug_init(void)
+{
+	aufs_bindex_t bindex;
+	struct au_vdir_destr destr;
+
+	bindex = -1;
+	AuDebugOn(bindex >= 0);
+
+	destr.len = -1;
+	AuDebugOn(destr.len < NAME_MAX);
+
+#ifdef CONFIG_4KSTACKS
+	AuWarn("CONFIG_4KSTACKS is defined.\n");
+#endif
+
+#ifdef AuForceNoBrs
+	sysaufs_brs = 0;
+#endif
+
+	return 0;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/debug.h linux-2.6.31.4/fs/aufs/debug.h
--- linux-2.6.31.4.orig/fs/aufs/debug.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/debug.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,260 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * debug print functions
+ */
+
+#ifndef __AUFS_DEBUG_H__
+#define __AUFS_DEBUG_H__
+
+#ifdef __KERNEL__
+
+#include <linux/bug.h>
+/* #include <linux/err.h> */
+/* #include <linux/init.h> */
+/* #include <linux/kernel.h> */
+#include <linux/delay.h>
+/* #include <linux/kd.h> */
+/* #include <linux/vt_kern.h> */
+#include <linux/sysrq.h>
+#include <linux/aufs_type.h>
+
+#ifdef CONFIG_AUFS_DEBUG
+#define AuDebugOn(a)		BUG_ON(a)
+
+/* module parameter */
+extern int aufs_debug;
+static inline void au_debug(int n)
+{
+	aufs_debug = n;
+	smp_mb();
+}
+
+static inline int au_debug_test(void)
+{
+	return aufs_debug;
+}
+#else
+#define AuDebugOn(a)		do {} while (0)
+#define au_debug()		do {} while (0)
+static inline int au_debug_test(void)
+{
+	return 0;
+}
+#endif /* CONFIG_AUFS_DEBUG */
+
+/* ---------------------------------------------------------------------- */
+
+/* debug print */
+
+#define AuDpri(lvl, fmt, arg...) \
+	printk(lvl AUFS_NAME " %s:%d:%s[%d]: " fmt, \
+	       __func__, __LINE__, current->comm, current->pid, ##arg)
+#define AuDbg(fmt, arg...) do { \
+	if (au_debug_test()) \
+		AuDpri(KERN_DEBUG, "DEBUG: " fmt, ##arg); \
+} while (0)
+#define AuLabel(l) 		AuDbg(#l "\n")
+#define AuInfo(fmt, arg...)	AuDpri(KERN_INFO, fmt, ##arg)
+#define AuWarn(fmt, arg...)	AuDpri(KERN_WARNING, fmt, ##arg)
+#define AuErr(fmt, arg...)	AuDpri(KERN_ERR, fmt, ##arg)
+#define AuIOErr(fmt, arg...)	AuErr("I/O Error, " fmt, ##arg)
+#define AuWarn1(fmt, arg...) do { \
+	static unsigned char _c; \
+	if (!_c++) \
+		AuWarn(fmt, ##arg); \
+} while (0)
+
+#define AuErr1(fmt, arg...) do { \
+	static unsigned char _c; \
+	if (!_c++) \
+		AuErr(fmt, ##arg); \
+} while (0)
+
+#define AuIOErr1(fmt, arg...) do { \
+	static unsigned char _c; \
+	if (!_c++) \
+		AuIOErr(fmt, ##arg); \
+} while (0)
+
+#define AuUnsupportMsg	"This operation is not supported." \
+			" Please report this application to aufs-users ML."
+#define AuUnsupport(fmt, args...) do { \
+	AuErr(AuUnsupportMsg "\n" fmt, ##args); \
+	dump_stack(); \
+} while (0)
+
+#define AuTraceErr(e) do { \
+	if (unlikely((e) < 0)) \
+		AuDbg("err %d\n", (int)(e)); \
+} while (0)
+
+#define AuTraceErrPtr(p) do { \
+	if (IS_ERR(p)) \
+		AuDbg("err %ld\n", PTR_ERR(p)); \
+} while (0)
+
+/* dirty macros for debug print, use with "%.*s" and caution */
+#define AuLNPair(qstr)		(qstr)->len, (qstr)->name
+#define AuDLNPair(d)		AuLNPair(&(d)->d_name)
+
+/* ---------------------------------------------------------------------- */
+
+struct au_sbinfo;
+struct au_finfo;
+struct dentry;
+#ifdef CONFIG_AUFS_DEBUG
+extern char *au_plevel;
+struct au_nhash;
+void au_dpri_whlist(struct au_nhash *whlist);
+struct au_vdir;
+void au_dpri_vdir(struct au_vdir *vdir);
+struct inode;
+void au_dpri_inode(struct inode *inode);
+void au_dpri_dentry(struct dentry *dentry);
+struct file;
+void au_dpri_file(struct file *filp);
+struct super_block;
+void au_dpri_sb(struct super_block *sb);
+
+void au_dbg_sleep_jiffy(int jiffy);
+struct iattr;
+void au_dbg_iattr(struct iattr *ia);
+
+void au_dbg_verify_dir_parent(struct dentry *dentry, unsigned int sigen);
+void au_dbg_verify_nondir_parent(struct dentry *dentry, unsigned int sigen);
+void au_dbg_verify_gen(struct dentry *parent, unsigned int sigen);
+void au_dbg_verify_hf(struct au_finfo *finfo);
+void au_dbg_verify_kthread(void);
+
+int __init au_debug_init(void);
+void au_debug_sbinfo_init(struct au_sbinfo *sbinfo);
+#define AuDbgWhlist(w) do { \
+	AuDbg(#w "\n"); \
+	au_dpri_whlist(w); \
+} while (0)
+
+#define AuDbgVdir(v) do { \
+	AuDbg(#v "\n"); \
+	au_dpri_vdir(v); \
+} while (0)
+
+#define AuDbgInode(i) do { \
+	AuDbg(#i "\n"); \
+	au_dpri_inode(i); \
+} while (0)
+
+#define AuDbgDentry(d) do { \
+	AuDbg(#d "\n"); \
+	au_dpri_dentry(d); \
+} while (0)
+
+#define AuDbgFile(f) do { \
+	AuDbg(#f "\n"); \
+	au_dpri_file(f); \
+} while (0)
+
+#define AuDbgSb(sb) do { \
+	AuDbg(#sb "\n"); \
+	au_dpri_sb(sb); \
+} while (0)
+
+#define AuDbgSleep(sec) do { \
+	AuDbg("sleep %d sec\n", sec); \
+	ssleep(sec); \
+} while (0)
+
+#define AuDbgSleepJiffy(jiffy) do { \
+	AuDbg("sleep %d jiffies\n", jiffy); \
+	au_dbg_sleep_jiffy(jiffy); \
+} while (0)
+
+#define AuDbgIAttr(ia) do { \
+	AuDbg("ia_valid 0x%x\n", (ia)->ia_valid); \
+	au_dbg_iattr(ia); \
+} while (0)
+#else
+static inline void au_dbg_verify_dir_parent(struct dentry *dentry,
+					    unsigned int sigen)
+{
+	/* empty */
+}
+static inline void au_dbg_verify_nondir_parent(struct dentry *dentry,
+					       unsigned int sigen)
+{
+	/* empty */
+}
+static inline void au_dbg_verify_gen(struct dentry *parent, unsigned int sigen)
+{
+	/* empty */
+}
+static inline void au_dbg_verify_hf(struct au_finfo *finfo)
+{
+	/* empty */
+}
+static inline void au_dbg_verify_kthread(void)
+{
+	/* empty */
+}
+
+static inline int au_debug_init(void)
+{
+	return 0;
+}
+static inline void au_debug_sbinfo_init(struct au_sbinfo *sbinfo)
+{
+	/* empty */
+}
+#define AuDbgWhlist(w)		do {} while (0)
+#define AuDbgVdir(v)		do {} while (0)
+#define AuDbgInode(i)		do {} while (0)
+#define AuDbgDentry(d)		do {} while (0)
+#define AuDbgFile(f)		do {} while (0)
+#define AuDbgSb(sb)		do {} while (0)
+#define AuDbgSleep(sec)		do {} while (0)
+#define AuDbgSleepJiffy(jiffy)	do {} while (0)
+#define AuDbgIAttr(ia)		do {} while (0)
+#endif /* CONFIG_AUFS_DEBUG */
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_MAGIC_SYSRQ
+int __init au_sysrq_init(void);
+void au_sysrq_fin(void);
+
+#ifdef CONFIG_HW_CONSOLE
+#define au_dbg_blocked() do { \
+	WARN_ON(1); \
+	handle_sysrq('w', vc_cons[fg_console].d->vc_tty); \
+} while (0)
+#else
+#define au_dbg_blocked()	do {} while (0)
+#endif
+
+#else
+static inline int au_sysrq_init(void)
+{
+	return 0;
+}
+#define au_sysrq_fin()		do {} while (0)
+#define au_dbg_blocked()	do {} while (0)
+#endif /* CONFIG_AUFS_MAGIC_SYSRQ */
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_DEBUG_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/dentry.c linux-2.6.31.4/fs/aufs/dentry.c
--- linux-2.6.31.4.orig/fs/aufs/dentry.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/dentry.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,880 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * lookup and dentry operations
+ */
+
+#include <linux/namei.h>
+#include "aufs.h"
+
+static void au_h_nd(struct nameidata *h_nd, struct nameidata *nd)
+{
+	if (nd) {
+		*h_nd = *nd;
+
+		/*
+		 * gave up supporting LOOKUP_CREATE/OPEN for lower fs,
+		 * due to whiteout and branch permission.
+		 */
+		h_nd->flags &= ~(/*LOOKUP_PARENT |*/ LOOKUP_OPEN | LOOKUP_CREATE
+				 | LOOKUP_FOLLOW);
+		/* unnecessary? */
+		h_nd->intent.open.file = NULL;
+	} else
+		memset(h_nd, 0, sizeof(*h_nd));
+}
+
+struct au_lkup_one_args {
+	struct dentry **errp;
+	struct qstr *name;
+	struct dentry *h_parent;
+	struct au_branch *br;
+	struct nameidata *nd;
+};
+
+struct dentry *au_lkup_one(struct qstr *name, struct dentry *h_parent,
+			   struct au_branch *br, struct nameidata *nd)
+{
+	struct dentry *h_dentry;
+	int err;
+	struct nameidata h_nd;
+
+	if (au_test_fs_null_nd(h_parent->d_sb))
+		return vfsub_lookup_one_len(name->name, h_parent, name->len);
+
+	au_h_nd(&h_nd, nd);
+	h_nd.path.dentry = h_parent;
+	h_nd.path.mnt = br->br_mnt;
+
+	err = __lookup_one_len(name->name, &h_nd.last, NULL, name->len);
+	h_dentry = ERR_PTR(err);
+	if (!err) {
+		path_get(&h_nd.path);
+		h_dentry = vfsub_lookup_hash(&h_nd);
+		path_put(&h_nd.path);
+	}
+
+	return h_dentry;
+}
+
+static void au_call_lkup_one(void *args)
+{
+	struct au_lkup_one_args *a = args;
+	*a->errp = au_lkup_one(a->name, a->h_parent, a->br, a->nd);
+}
+
+#define AuLkup_ALLOW_NEG	1
+#define au_ftest_lkup(flags, name)	((flags) & AuLkup_##name)
+#define au_fset_lkup(flags, name)	{ (flags) |= AuLkup_##name; }
+#define au_fclr_lkup(flags, name)	{ (flags) &= ~AuLkup_##name; }
+
+struct au_do_lookup_args {
+	unsigned int		flags;
+	mode_t			type;
+	struct nameidata	*nd;
+};
+
+/*
+ * returns positive/negative dentry, NULL or an error.
+ * NULL means whiteout-ed or not-found.
+ */
+static struct dentry*
+au_do_lookup(struct dentry *h_parent, struct dentry *dentry,
+	     aufs_bindex_t bindex, struct qstr *wh_name,
+	     struct au_do_lookup_args *args)
+{
+	struct dentry *h_dentry;
+	struct inode *h_inode, *inode;
+	struct qstr *name;
+	struct au_branch *br;
+	int wh_found, opq;
+	unsigned char wh_able;
+	const unsigned char allow_neg = !!au_ftest_lkup(args->flags, ALLOW_NEG);
+
+	name = &dentry->d_name;
+	wh_found = 0;
+	br = au_sbr(dentry->d_sb, bindex);
+	wh_able = !!au_br_whable(br->br_perm);
+	if (wh_able)
+		wh_found = au_wh_test(h_parent, wh_name, br, /*try_sio*/0);
+	h_dentry = ERR_PTR(wh_found);
+	if (!wh_found)
+		goto real_lookup;
+	if (unlikely(wh_found < 0))
+		goto out;
+
+	/* We found a whiteout */
+	/* au_set_dbend(dentry, bindex); */
+	au_set_dbwh(dentry, bindex);
+	if (!allow_neg)
+		return NULL; /* success */
+
+ real_lookup:
+	h_dentry = au_lkup_one(name, h_parent, br, args->nd);
+	if (IS_ERR(h_dentry))
+		goto out;
+
+	h_inode = h_dentry->d_inode;
+	if (!h_inode) {
+		if (!allow_neg)
+			goto out_neg;
+	} else if (wh_found
+		   || (args->type && args->type != (h_inode->i_mode & S_IFMT)))
+		goto out_neg;
+
+	if (au_dbend(dentry) <= bindex)
+		au_set_dbend(dentry, bindex);
+	if (au_dbstart(dentry) < 0 || bindex < au_dbstart(dentry))
+		au_set_dbstart(dentry, bindex);
+	au_set_h_dptr(dentry, bindex, h_dentry);
+
+	inode = dentry->d_inode;
+	if (!h_inode || !S_ISDIR(h_inode->i_mode) || !wh_able
+	    || (inode && !S_ISDIR(inode->i_mode)))
+		goto out; /* success */
+
+	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+	opq = au_diropq_test(h_dentry, br);
+	mutex_unlock(&h_inode->i_mutex);
+	if (opq > 0)
+		au_set_dbdiropq(dentry, bindex);
+	else if (unlikely(opq < 0)) {
+		au_set_h_dptr(dentry, bindex, NULL);
+		h_dentry = ERR_PTR(opq);
+	}
+	goto out;
+
+ out_neg:
+	dput(h_dentry);
+	h_dentry = NULL;
+ out:
+	return h_dentry;
+}
+
+static int au_test_shwh(struct super_block *sb, const struct qstr *name)
+{
+	if (unlikely(!au_opt_test(au_mntflags(sb), SHWH)
+		     && !strncmp(name->name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)))
+		return -EPERM;
+	return 0;
+}
+
+/*
+ * returns the number of lower positive dentries,
+ * otherwise an error.
+ * can be called at unlinking with @type is zero.
+ */
+int au_lkup_dentry(struct dentry *dentry, aufs_bindex_t bstart, mode_t type,
+		   struct nameidata *nd)
+{
+	int npositive, err;
+	aufs_bindex_t bindex, btail, bdiropq;
+	unsigned char isdir;
+	struct qstr whname;
+	struct au_do_lookup_args args = {
+		.flags	= 0,
+		.type	= type,
+		.nd	= nd
+	};
+	const struct qstr *name = &dentry->d_name;
+	struct dentry *parent;
+	struct inode *inode;
+
+	parent = dget_parent(dentry);
+	err = au_test_shwh(dentry->d_sb, name);
+	if (unlikely(err))
+		goto out;
+
+	err = au_wh_name_alloc(&whname, name);
+	if (unlikely(err))
+		goto out;
+
+	inode = dentry->d_inode;
+	isdir = !!(inode && S_ISDIR(inode->i_mode));
+	if (!type)
+		au_fset_lkup(args.flags, ALLOW_NEG);
+
+	npositive = 0;
+	btail = au_dbtaildir(parent);
+	for (bindex = bstart; bindex <= btail; bindex++) {
+		struct dentry *h_parent, *h_dentry;
+		struct inode *h_inode, *h_dir;
+
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (h_dentry) {
+			if (h_dentry->d_inode)
+				npositive++;
+			if (type != S_IFDIR)
+				break;
+			continue;
+		}
+		h_parent = au_h_dptr(parent, bindex);
+		if (!h_parent)
+			continue;
+		h_dir = h_parent->d_inode;
+		if (!h_dir || !S_ISDIR(h_dir->i_mode))
+			continue;
+
+		mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+		h_dentry = au_do_lookup(h_parent, dentry, bindex, &whname,
+					&args);
+		mutex_unlock(&h_dir->i_mutex);
+		err = PTR_ERR(h_dentry);
+		if (IS_ERR(h_dentry))
+			goto out_wh;
+		au_fclr_lkup(args.flags, ALLOW_NEG);
+
+		if (au_dbwh(dentry) >= 0)
+			break;
+		if (!h_dentry)
+			continue;
+		h_inode = h_dentry->d_inode;
+		if (!h_inode)
+			continue;
+		npositive++;
+		if (!args.type)
+			args.type = h_inode->i_mode & S_IFMT;
+		if (args.type != S_IFDIR)
+			break;
+		else if (isdir) {
+			/* the type of lower may be different */
+			bdiropq = au_dbdiropq(dentry);
+			if (bdiropq >= 0 && bdiropq <= bindex)
+				break;
+		}
+	}
+
+	if (npositive) {
+		AuLabel(positive);
+		au_update_dbstart(dentry);
+	}
+	err = npositive;
+	if (unlikely(!au_opt_test(au_mntflags(dentry->d_sb), UDBA_NONE)
+		     && au_dbstart(dentry) < 0))
+		/* both of real entry and whiteout found */
+		err = -EIO;
+
+ out_wh:
+	kfree(whname.name);
+ out:
+	dput(parent);
+	return err;
+}
+
+struct dentry *au_sio_lkup_one(struct qstr *name, struct dentry *parent,
+			       struct au_branch *br)
+{
+	struct dentry *dentry;
+	int wkq_err;
+
+	if (!au_test_h_perm_sio(parent->d_inode, MAY_EXEC))
+		dentry = au_lkup_one(name, parent, br, /*nd*/NULL);
+	else {
+		struct au_lkup_one_args args = {
+			.errp		= &dentry,
+			.name		= name,
+			.h_parent	= parent,
+			.br		= br,
+			.nd		= NULL
+		};
+
+		wkq_err = au_wkq_wait(au_call_lkup_one, &args);
+		if (unlikely(wkq_err))
+			dentry = ERR_PTR(wkq_err);
+	}
+
+	return dentry;
+}
+
+/*
+ * lookup @dentry on @bindex which should be negative.
+ */
+int au_lkup_neg(struct dentry *dentry, aufs_bindex_t bindex)
+{
+	int err;
+	struct dentry *parent, *h_parent, *h_dentry;
+	struct qstr *name;
+
+	name = &dentry->d_name;
+	parent = dget_parent(dentry);
+	h_parent = au_h_dptr(parent, bindex);
+	h_dentry = au_sio_lkup_one(name, h_parent,
+				   au_sbr(dentry->d_sb, bindex));
+	err = PTR_ERR(h_dentry);
+	if (IS_ERR(h_dentry))
+		goto out;
+	if (unlikely(h_dentry->d_inode)) {
+		err = -EIO;
+		AuIOErr("b%d %.*s should be negative.\n",
+			bindex, AuDLNPair(h_dentry));
+		dput(h_dentry);
+		goto out;
+	}
+
+	if (bindex < au_dbstart(dentry))
+		au_set_dbstart(dentry, bindex);
+	if (au_dbend(dentry) < bindex)
+		au_set_dbend(dentry, bindex);
+	au_set_h_dptr(dentry, bindex, h_dentry);
+	err = 0;
+
+ out:
+	dput(parent);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* subset of struct inode */
+struct au_iattr {
+	unsigned long		i_ino;
+	/* unsigned int		i_nlink; */
+	uid_t			i_uid;
+	gid_t			i_gid;
+	u64			i_version;
+/*
+	loff_t			i_size;
+	blkcnt_t		i_blocks;
+*/
+	umode_t			i_mode;
+};
+
+static void au_iattr_save(struct au_iattr *ia, struct inode *h_inode)
+{
+	ia->i_ino = h_inode->i_ino;
+	/* ia->i_nlink = h_inode->i_nlink; */
+	ia->i_uid = h_inode->i_uid;
+	ia->i_gid = h_inode->i_gid;
+	ia->i_version = h_inode->i_version;
+/*
+	ia->i_size = h_inode->i_size;
+	ia->i_blocks = h_inode->i_blocks;
+*/
+	ia->i_mode = (h_inode->i_mode & S_IFMT);
+}
+
+static int au_iattr_test(struct au_iattr *ia, struct inode *h_inode)
+{
+	return ia->i_ino != h_inode->i_ino
+		/* || ia->i_nlink != h_inode->i_nlink */
+		|| ia->i_uid != h_inode->i_uid
+		|| ia->i_gid != h_inode->i_gid
+		|| ia->i_version != h_inode->i_version
+/*
+		|| ia->i_size != h_inode->i_size
+		|| ia->i_blocks != h_inode->i_blocks
+*/
+		|| ia->i_mode != (h_inode->i_mode & S_IFMT);
+}
+
+static int au_h_verify_dentry(struct dentry *h_dentry, struct dentry *h_parent,
+			      struct au_branch *br)
+{
+	int err;
+	struct au_iattr ia;
+	struct inode *h_inode;
+	struct dentry *h_d;
+	struct super_block *h_sb;
+
+	err = 0;
+	memset(&ia, -1, sizeof(ia));
+	h_sb = h_dentry->d_sb;
+	h_inode = h_dentry->d_inode;
+	if (h_inode)
+		au_iattr_save(&ia, h_inode);
+	else if (au_test_nfs(h_sb) || au_test_fuse(h_sb))
+		/* nfs d_revalidate may return 0 for negative dentry */
+		/* fuse d_revalidate always return 0 for negative dentry */
+		goto out;
+
+	/* main purpose is namei.c:cached_lookup() and d_revalidate */
+	h_d = au_lkup_one(&h_dentry->d_name, h_parent, br, /*nd*/NULL);
+	err = PTR_ERR(h_d);
+	if (IS_ERR(h_d))
+		goto out;
+
+	err = 0;
+	if (unlikely(h_d != h_dentry
+		     || h_d->d_inode != h_inode
+		     || (h_inode && au_iattr_test(&ia, h_inode))))
+		err = au_busy_or_stale();
+	dput(h_d);
+
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+int au_h_verify(struct dentry *h_dentry, unsigned int udba, struct inode *h_dir,
+		struct dentry *h_parent, struct au_branch *br)
+{
+	int err;
+
+	err = 0;
+	if (udba == AuOpt_UDBA_REVAL) {
+		IMustLock(h_dir);
+		err = (h_dentry->d_parent->d_inode != h_dir);
+	} else if (udba == AuOpt_UDBA_HINOTIFY)
+		err = au_h_verify_dentry(h_dentry, h_parent, br);
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void au_do_refresh_hdentry(struct au_hdentry *p, struct au_dinfo *dinfo,
+				  struct dentry *parent)
+{
+	struct dentry *h_d, *h_dp;
+	struct au_hdentry tmp, *q;
+	struct super_block *sb;
+	aufs_bindex_t new_bindex, bindex, bend, bwh, bdiropq;
+
+	AuRwMustWriteLock(&dinfo->di_rwsem);
+
+	bend = dinfo->di_bend;
+	bwh = dinfo->di_bwh;
+	bdiropq = dinfo->di_bdiropq;
+	for (bindex = dinfo->di_bstart; bindex <= bend; bindex++, p++) {
+		h_d = p->hd_dentry;
+		if (!h_d)
+			continue;
+
+		h_dp = dget_parent(h_d);
+		if (h_dp == au_h_dptr(parent, bindex)) {
+			dput(h_dp);
+			continue;
+		}
+
+		new_bindex = au_find_dbindex(parent, h_dp);
+		dput(h_dp);
+		if (dinfo->di_bwh == bindex)
+			bwh = new_bindex;
+		if (dinfo->di_bdiropq == bindex)
+			bdiropq = new_bindex;
+		if (new_bindex < 0) {
+			au_hdput(p);
+			p->hd_dentry = NULL;
+			continue;
+		}
+
+		/* swap two lower dentries, and loop again */
+		q = dinfo->di_hdentry + new_bindex;
+		tmp = *q;
+		*q = *p;
+		*p = tmp;
+		if (tmp.hd_dentry) {
+			bindex--;
+			p--;
+		}
+	}
+
+	sb = parent->d_sb;
+	dinfo->di_bwh = -1;
+	if (bwh >= 0 && bwh <= au_sbend(sb) && au_sbr_whable(sb, bwh))
+		dinfo->di_bwh = bwh;
+
+	dinfo->di_bdiropq = -1;
+	if (bdiropq >= 0
+	    && bdiropq <= au_sbend(sb)
+	    && au_sbr_whable(sb, bdiropq))
+		dinfo->di_bdiropq = bdiropq;
+
+	bend = au_dbend(parent);
+	p = dinfo->di_hdentry;
+	for (bindex = 0; bindex <= bend; bindex++, p++)
+		if (p->hd_dentry) {
+			dinfo->di_bstart = bindex;
+			break;
+		}
+
+	p = dinfo->di_hdentry + bend;
+	for (bindex = bend; bindex >= 0; bindex--, p--)
+		if (p->hd_dentry) {
+			dinfo->di_bend = bindex;
+			break;
+		}
+}
+
+/*
+ * returns the number of found lower positive dentries,
+ * otherwise an error.
+ */
+int au_refresh_hdentry(struct dentry *dentry, mode_t type)
+{
+	int npositive, err;
+	unsigned int sigen;
+	aufs_bindex_t bstart;
+	struct au_dinfo *dinfo;
+	struct super_block *sb;
+	struct dentry *parent;
+
+	DiMustWriteLock(dentry);
+
+	sb = dentry->d_sb;
+	AuDebugOn(IS_ROOT(dentry));
+	sigen = au_sigen(sb);
+	parent = dget_parent(dentry);
+	AuDebugOn(au_digen(parent) != sigen
+		  || au_iigen(parent->d_inode) != sigen);
+
+	dinfo = au_di(dentry);
+	err = au_di_realloc(dinfo, au_sbend(sb) + 1);
+	npositive = err;
+	if (unlikely(err))
+		goto out;
+	au_do_refresh_hdentry(dinfo->di_hdentry + dinfo->di_bstart, dinfo,
+			      parent);
+
+	npositive = 0;
+	bstart = au_dbstart(parent);
+	if (type != S_IFDIR && dinfo->di_bstart == bstart)
+		goto out_dgen; /* success */
+
+	npositive = au_lkup_dentry(dentry, bstart, type, /*nd*/NULL);
+	if (npositive < 0)
+		goto out;
+	if (dinfo->di_bwh >= 0 && dinfo->di_bwh <= dinfo->di_bstart)
+		d_drop(dentry);
+
+ out_dgen:
+	au_update_digen(dentry);
+ out:
+	dput(parent);
+	AuTraceErr(npositive);
+	return npositive;
+}
+
+static noinline_for_stack
+int au_do_h_d_reval(struct dentry *h_dentry, struct nameidata *nd,
+		    struct dentry *dentry, aufs_bindex_t bindex)
+{
+	int err, valid;
+	int (*reval)(struct dentry *, struct nameidata *);
+
+	err = 0;
+	reval = NULL;
+	if (h_dentry->d_op)
+		reval = h_dentry->d_op->d_revalidate;
+	if (!reval)
+		goto out;
+
+	AuDbg("b%d\n", bindex);
+	if (au_test_fs_null_nd(h_dentry->d_sb))
+		/* it may return tri-state */
+		valid = reval(h_dentry, NULL);
+	else {
+		struct nameidata h_nd;
+		int locked;
+		struct dentry *parent;
+
+		au_h_nd(&h_nd, nd);
+		parent = nd->path.dentry;
+		locked = (nd && nd->path.dentry != dentry);
+		if (locked)
+			di_read_lock_parent(parent, AuLock_IR);
+		BUG_ON(bindex > au_dbend(parent));
+		h_nd.path.dentry = au_h_dptr(parent, bindex);
+		BUG_ON(!h_nd.path.dentry);
+		h_nd.path.mnt = au_sbr(parent->d_sb, bindex)->br_mnt;
+		path_get(&h_nd.path);
+		valid = reval(h_dentry, &h_nd);
+		path_put(&h_nd.path);
+		if (locked)
+			di_read_unlock(parent, AuLock_IR);
+	}
+
+	if (unlikely(valid < 0))
+		err = valid;
+	else if (!valid)
+		err = -EINVAL;
+
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+/* todo: remove this */
+static int h_d_revalidate(struct dentry *dentry, struct inode *inode,
+			  struct nameidata *nd, int do_udba)
+{
+	int err;
+	umode_t mode, h_mode;
+	aufs_bindex_t bindex, btail, bstart, ibs, ibe;
+	unsigned char plus, unhashed, is_root, h_plus;
+	struct inode *first, *h_inode, *h_cached_inode;
+	struct dentry *h_dentry;
+	struct qstr *name, *h_name;
+
+	err = 0;
+	plus = 0;
+	mode = 0;
+	first = NULL;
+	ibs = -1;
+	ibe = -1;
+	unhashed = !!d_unhashed(dentry);
+	is_root = !!IS_ROOT(dentry);
+	name = &dentry->d_name;
+
+	/*
+	 * Theoretically, REVAL test should be unnecessary in case of INOTIFY.
+	 * But inotify doesn't fire some necessary events,
+	 *	IN_ATTRIB for atime/nlink/pageio
+	 *	IN_DELETE for NFS dentry
+	 * Let's do REVAL test too.
+	 */
+	if (do_udba && inode) {
+		mode = (inode->i_mode & S_IFMT);
+		plus = (inode->i_nlink > 0);
+		first = au_h_iptr(inode, au_ibstart(inode));
+		ibs = au_ibstart(inode);
+		ibe = au_ibend(inode);
+	}
+
+	bstart = au_dbstart(dentry);
+	btail = bstart;
+	if (inode && S_ISDIR(inode->i_mode))
+		btail = au_dbtaildir(dentry);
+	for (bindex = bstart; bindex <= btail; bindex++) {
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (!h_dentry)
+			continue;
+
+		AuDbg("b%d, %.*s\n", bindex, AuDLNPair(h_dentry));
+		h_name = &h_dentry->d_name;
+		if (unlikely(do_udba
+			     && !is_root
+			     && (unhashed != !!d_unhashed(h_dentry)
+				 || name->len != h_name->len
+				 || memcmp(name->name, h_name->name, name->len))
+			    )) {
+			AuDbg("unhash 0x%x 0x%x, %.*s %.*s\n",
+				  unhashed, d_unhashed(h_dentry),
+				  AuDLNPair(dentry), AuDLNPair(h_dentry));
+			goto err;
+		}
+
+		err = au_do_h_d_reval(h_dentry, nd, dentry, bindex);
+		if (unlikely(err))
+			/* do not goto err, to keep the errno */
+			break;
+
+		/* todo: plink too? */
+		if (!do_udba)
+			continue;
+
+		/* UDBA tests */
+		h_inode = h_dentry->d_inode;
+		if (unlikely(!!inode != !!h_inode))
+			goto err;
+
+		h_plus = plus;
+		h_mode = mode;
+		h_cached_inode = h_inode;
+		if (h_inode) {
+			h_mode = (h_inode->i_mode & S_IFMT);
+			h_plus = (h_inode->i_nlink > 0);
+		}
+		if (inode && ibs <= bindex && bindex <= ibe)
+			h_cached_inode = au_h_iptr(inode, bindex);
+
+		if (unlikely(plus != h_plus
+			     || mode != h_mode
+			     || h_cached_inode != h_inode))
+			goto err;
+		continue;
+
+	err:
+		err = -EINVAL;
+		break;
+	}
+
+	return err;
+}
+
+static int simple_reval_dpath(struct dentry *dentry, unsigned int sigen)
+{
+	int err;
+	struct dentry *parent;
+	struct inode *inode;
+
+	inode = dentry->d_inode;
+	if (au_digen(dentry) == sigen && au_iigen(inode) == sigen)
+		return 0;
+
+	parent = dget_parent(dentry);
+	di_read_lock_parent(parent, AuLock_IR);
+	AuDebugOn(au_digen(parent) != sigen
+		  || au_iigen(parent->d_inode) != sigen);
+	au_dbg_verify_gen(parent, sigen);
+
+	/* returns a number of positive dentries */
+	err = au_refresh_hdentry(dentry, inode->i_mode & S_IFMT);
+	if (err >= 0)
+		err = au_refresh_hinode(inode, dentry);
+
+	di_read_unlock(parent, AuLock_IR);
+	dput(parent);
+	return err;
+}
+
+int au_reval_dpath(struct dentry *dentry, unsigned int sigen)
+{
+	int err;
+	struct dentry *d, *parent;
+	struct inode *inode;
+
+	if (!au_ftest_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIRS))
+		return simple_reval_dpath(dentry, sigen);
+
+	/* slow loop, keep it simple and stupid */
+	/* cf: au_cpup_dirs() */
+	err = 0;
+	parent = NULL;
+	while (au_digen(dentry) != sigen
+	       || au_iigen(dentry->d_inode) != sigen) {
+		d = dentry;
+		while (1) {
+			dput(parent);
+			parent = dget_parent(d);
+			if (au_digen(parent) == sigen
+			    && au_iigen(parent->d_inode) == sigen)
+				break;
+			d = parent;
+		}
+
+		inode = d->d_inode;
+		if (d != dentry)
+			di_write_lock_child(d);
+
+		/* someone might update our dentry while we were sleeping */
+		if (au_digen(d) != sigen || au_iigen(d->d_inode) != sigen) {
+			di_read_lock_parent(parent, AuLock_IR);
+			/* returns a number of positive dentries */
+			err = au_refresh_hdentry(d, inode->i_mode & S_IFMT);
+			if (err >= 0)
+				err = au_refresh_hinode(inode, d);
+			di_read_unlock(parent, AuLock_IR);
+		}
+
+		if (d != dentry)
+			di_write_unlock(d);
+		dput(parent);
+		if (unlikely(err))
+			break;
+	}
+
+	return err;
+}
+
+/*
+ * if valid returns 1, otherwise 0.
+ */
+static int aufs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+	int valid, err;
+	unsigned int sigen;
+	unsigned char do_udba;
+	struct super_block *sb;
+	struct inode *inode;
+
+	err = -EINVAL;
+	sb = dentry->d_sb;
+	inode = dentry->d_inode;
+	aufs_read_lock(dentry, AuLock_FLUSH | AuLock_DW);
+	sigen = au_sigen(sb);
+	if (au_digen(dentry) != sigen) {
+		AuDebugOn(IS_ROOT(dentry));
+		if (inode)
+			err = au_reval_dpath(dentry, sigen);
+		if (unlikely(err))
+			goto out_dgrade;
+		AuDebugOn(au_digen(dentry) != sigen);
+	}
+	if (inode && au_iigen(inode) != sigen) {
+		AuDebugOn(IS_ROOT(dentry));
+		err = au_refresh_hinode(inode, dentry);
+		if (unlikely(err))
+			goto out_dgrade;
+		AuDebugOn(au_iigen(inode) != sigen);
+	}
+	di_downgrade_lock(dentry, AuLock_IR);
+
+	AuDebugOn(au_digen(dentry) != sigen);
+	AuDebugOn(inode && au_iigen(inode) != sigen);
+	err = -EINVAL;
+	do_udba = !au_opt_test(au_mntflags(sb), UDBA_NONE);
+	if (do_udba && inode) {
+		aufs_bindex_t bstart = au_ibstart(inode);
+
+		if (bstart >= 0
+		    && au_test_higen(inode, au_h_iptr(inode, bstart)))
+			goto out;
+	}
+
+	err = h_d_revalidate(dentry, inode, nd, do_udba);
+	if (unlikely(!err && do_udba && au_dbstart(dentry) < 0))
+		/* both of real entry and whiteout found */
+		err = -EIO;
+	goto out;
+
+ out_dgrade:
+	di_downgrade_lock(dentry, AuLock_IR);
+ out:
+	au_store_oflag(nd, inode);
+	aufs_read_unlock(dentry, AuLock_IR);
+	AuTraceErr(err);
+	valid = !err;
+	if (!valid)
+		AuDbg("%.*s invalid\n", AuDLNPair(dentry));
+	return valid;
+}
+
+static void aufs_d_release(struct dentry *dentry)
+{
+	struct au_dinfo *dinfo;
+	aufs_bindex_t bend, bindex;
+
+	dinfo = dentry->d_fsdata;
+	if (!dinfo)
+		return;
+
+	/* dentry may not be revalidated */
+	bindex = dinfo->di_bstart;
+	if (bindex >= 0) {
+		struct au_hdentry *p;
+
+		bend = dinfo->di_bend;
+		p = dinfo->di_hdentry + bindex;
+		while (bindex++ <= bend) {
+			if (p->hd_dentry)
+				au_hdput(p);
+			p++;
+		}
+	}
+	kfree(dinfo->di_hdentry);
+	AuRwDestroy(&dinfo->di_rwsem);
+	au_cache_free_dinfo(dinfo);
+	au_hin_di_reinit(dentry);
+}
+
+struct dentry_operations aufs_dop = {
+	.d_revalidate	= aufs_d_revalidate,
+	.d_release	= aufs_d_release
+};
diff -Nur linux-2.6.31.4.orig/fs/aufs/dentry.h linux-2.6.31.4/fs/aufs/dentry.h
--- linux-2.6.31.4.orig/fs/aufs/dentry.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/dentry.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,231 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * lookup and dentry operations
+ */
+
+#ifndef __AUFS_DENTRY_H__
+#define __AUFS_DENTRY_H__
+
+#ifdef __KERNEL__
+
+#include <linux/dcache.h>
+#include <linux/aufs_type.h>
+#include "rwsem.h"
+
+/* make a single member structure for future use */
+/* todo: remove this structure */
+struct au_hdentry {
+	struct dentry		*hd_dentry;
+};
+
+struct au_dinfo {
+	atomic_t		di_generation;
+
+	struct au_rwsem		di_rwsem;
+	aufs_bindex_t		di_bstart, di_bend, di_bwh, di_bdiropq;
+	struct au_hdentry	*di_hdentry;
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* dentry.c */
+extern struct dentry_operations aufs_dop;
+struct au_branch;
+struct dentry *au_lkup_one(struct qstr *name, struct dentry *h_parent,
+			   struct au_branch *br, struct nameidata *nd);
+struct dentry *au_sio_lkup_one(struct qstr *name, struct dentry *parent,
+			       struct au_branch *br);
+int au_h_verify(struct dentry *h_dentry, unsigned int udba, struct inode *h_dir,
+		struct dentry *h_parent, struct au_branch *br);
+
+int au_lkup_dentry(struct dentry *dentry, aufs_bindex_t bstart, mode_t type,
+		   struct nameidata *nd);
+int au_lkup_neg(struct dentry *dentry, aufs_bindex_t bindex);
+int au_refresh_hdentry(struct dentry *dentry, mode_t type);
+int au_reval_dpath(struct dentry *dentry, unsigned int sigen);
+
+/* dinfo.c */
+int au_alloc_dinfo(struct dentry *dentry);
+int au_di_realloc(struct au_dinfo *dinfo, int nbr);
+
+void di_read_lock(struct dentry *d, int flags, unsigned int lsc);
+void di_read_unlock(struct dentry *d, int flags);
+void di_downgrade_lock(struct dentry *d, int flags);
+void di_write_lock(struct dentry *d, unsigned int lsc);
+void di_write_unlock(struct dentry *d);
+void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir);
+void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir);
+void di_write_unlock2(struct dentry *d1, struct dentry *d2);
+
+struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex);
+aufs_bindex_t au_dbtail(struct dentry *dentry);
+aufs_bindex_t au_dbtaildir(struct dentry *dentry);
+
+void au_set_h_dptr(struct dentry *dentry, aufs_bindex_t bindex,
+		   struct dentry *h_dentry);
+void au_update_digen(struct dentry *dentry);
+void au_update_dbrange(struct dentry *dentry, int do_put_zero);
+void au_update_dbstart(struct dentry *dentry);
+void au_update_dbend(struct dentry *dentry);
+int au_find_dbindex(struct dentry *dentry, struct dentry *h_dentry);
+
+/* ---------------------------------------------------------------------- */
+
+static inline struct au_dinfo *au_di(struct dentry *dentry)
+{
+	return dentry->d_fsdata;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* lock subclass for dinfo */
+enum {
+	AuLsc_DI_CHILD,		/* child first */
+	AuLsc_DI_CHILD2,	/* rename(2), link(2), and cpup at hinotify */
+	AuLsc_DI_CHILD3,	/* copyup dirs */
+	AuLsc_DI_PARENT,
+	AuLsc_DI_PARENT2,
+	AuLsc_DI_PARENT3
+};
+
+/*
+ * di_read_lock_child, di_write_lock_child,
+ * di_read_lock_child2, di_write_lock_child2,
+ * di_read_lock_child3, di_write_lock_child3,
+ * di_read_lock_parent, di_write_lock_parent,
+ * di_read_lock_parent2, di_write_lock_parent2,
+ * di_read_lock_parent3, di_write_lock_parent3,
+ */
+#define AuReadLockFunc(name, lsc) \
+static inline void di_read_lock_##name(struct dentry *d, int flags) \
+{ di_read_lock(d, flags, AuLsc_DI_##lsc); }
+
+#define AuWriteLockFunc(name, lsc) \
+static inline void di_write_lock_##name(struct dentry *d) \
+{ di_write_lock(d, AuLsc_DI_##lsc); }
+
+#define AuRWLockFuncs(name, lsc) \
+	AuReadLockFunc(name, lsc) \
+	AuWriteLockFunc(name, lsc)
+
+AuRWLockFuncs(child, CHILD);
+AuRWLockFuncs(child2, CHILD2);
+AuRWLockFuncs(child3, CHILD3);
+AuRWLockFuncs(parent, PARENT);
+AuRWLockFuncs(parent2, PARENT2);
+AuRWLockFuncs(parent3, PARENT3);
+
+#undef AuReadLockFunc
+#undef AuWriteLockFunc
+#undef AuRWLockFuncs
+
+#define DiMustNoWaiters(d)	AuRwMustNoWaiters(&au_di(d)->di_rwsem)
+#define DiMustAnyLock(d)	AuRwMustAnyLock(&au_di(d)->di_rwsem)
+#define DiMustWriteLock(d)	AuRwMustWriteLock(&au_di(d)->di_rwsem)
+
+/* ---------------------------------------------------------------------- */
+
+/* todo: memory barrier? */
+static inline unsigned int au_digen(struct dentry *d)
+{
+	return atomic_read(&au_di(d)->di_generation);
+}
+
+static inline void au_h_dentry_init(struct au_hdentry *hdentry)
+{
+	hdentry->hd_dentry = NULL;
+}
+
+static inline void au_hdput(struct au_hdentry *hd)
+{
+	dput(hd->hd_dentry);
+}
+
+static inline aufs_bindex_t au_dbstart(struct dentry *dentry)
+{
+	DiMustAnyLock(dentry);
+	return au_di(dentry)->di_bstart;
+}
+
+static inline aufs_bindex_t au_dbend(struct dentry *dentry)
+{
+	DiMustAnyLock(dentry);
+	return au_di(dentry)->di_bend;
+}
+
+static inline aufs_bindex_t au_dbwh(struct dentry *dentry)
+{
+	DiMustAnyLock(dentry);
+	return au_di(dentry)->di_bwh;
+}
+
+static inline aufs_bindex_t au_dbdiropq(struct dentry *dentry)
+{
+	DiMustAnyLock(dentry);
+	return au_di(dentry)->di_bdiropq;
+}
+
+/* todo: hard/soft set? */
+static inline void au_set_dbstart(struct dentry *dentry, aufs_bindex_t bindex)
+{
+	DiMustWriteLock(dentry);
+	au_di(dentry)->di_bstart = bindex;
+}
+
+static inline void au_set_dbend(struct dentry *dentry, aufs_bindex_t bindex)
+{
+	DiMustWriteLock(dentry);
+	au_di(dentry)->di_bend = bindex;
+}
+
+static inline void au_set_dbwh(struct dentry *dentry, aufs_bindex_t bindex)
+{
+	DiMustWriteLock(dentry);
+	/* dbwh can be outside of bstart - bend range */
+	au_di(dentry)->di_bwh = bindex;
+}
+
+static inline void au_set_dbdiropq(struct dentry *dentry, aufs_bindex_t bindex)
+{
+	DiMustWriteLock(dentry);
+	au_di(dentry)->di_bdiropq = bindex;
+}
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_HINOTIFY
+static inline void au_digen_dec(struct dentry *d)
+{
+	atomic_dec_return(&au_di(d)->di_generation);
+}
+
+static inline void au_hin_di_reinit(struct dentry *dentry)
+{
+	dentry->d_fsdata = NULL;
+}
+#else
+static inline void au_hin_di_reinit(struct dentry *dentry __maybe_unused)
+{
+	/* empty */
+}
+#endif /* CONFIG_AUFS_HINOTIFY */
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_DENTRY_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/dinfo.c linux-2.6.31.4/fs/aufs/dinfo.c
--- linux-2.6.31.4.orig/fs/aufs/dinfo.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/dinfo.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,367 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * dentry private data
+ */
+
+#include "aufs.h"
+
+int au_alloc_dinfo(struct dentry *dentry)
+{
+	struct au_dinfo *dinfo;
+	struct super_block *sb;
+	int nbr;
+
+	dinfo = au_cache_alloc_dinfo();
+	if (unlikely(!dinfo))
+		goto out;
+
+	sb = dentry->d_sb;
+	nbr = au_sbend(sb) + 1;
+	if (nbr <= 0)
+		nbr = 1;
+	dinfo->di_hdentry = kcalloc(nbr, sizeof(*dinfo->di_hdentry), GFP_NOFS);
+	if (unlikely(!dinfo->di_hdentry))
+		goto out_dinfo;
+
+	atomic_set(&dinfo->di_generation, au_sigen(sb));
+	/* smp_mb(); */ /* atomic_set */
+	au_rw_init_wlock_nested(&dinfo->di_rwsem, AuLsc_DI_CHILD);
+	dinfo->di_bstart = -1;
+	dinfo->di_bend = -1;
+	dinfo->di_bwh = -1;
+	dinfo->di_bdiropq = -1;
+
+	dentry->d_fsdata = dinfo;
+	dentry->d_op = &aufs_dop;
+	return 0; /* success */
+
+ out_dinfo:
+	au_cache_free_dinfo(dinfo);
+ out:
+	return -ENOMEM;
+}
+
+int au_di_realloc(struct au_dinfo *dinfo, int nbr)
+{
+	int err, sz;
+	struct au_hdentry *hdp;
+
+	AuRwMustWriteLock(&dinfo->di_rwsem);
+
+	err = -ENOMEM;
+	sz = sizeof(*hdp) * (dinfo->di_bend + 1);
+	if (!sz)
+		sz = sizeof(*hdp);
+	hdp = au_kzrealloc(dinfo->di_hdentry, sz, sizeof(*hdp) * nbr, GFP_NOFS);
+	if (hdp) {
+		dinfo->di_hdentry = hdp;
+		err = 0;
+	}
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void do_ii_write_lock(struct inode *inode, unsigned int lsc)
+{
+	switch (lsc) {
+	case AuLsc_DI_CHILD:
+		ii_write_lock_child(inode);
+		break;
+	case AuLsc_DI_CHILD2:
+		ii_write_lock_child2(inode);
+		break;
+	case AuLsc_DI_CHILD3:
+		ii_write_lock_child3(inode);
+		break;
+	case AuLsc_DI_PARENT:
+		ii_write_lock_parent(inode);
+		break;
+	case AuLsc_DI_PARENT2:
+		ii_write_lock_parent2(inode);
+		break;
+	case AuLsc_DI_PARENT3:
+		ii_write_lock_parent3(inode);
+		break;
+	default:
+		BUG();
+	}
+}
+
+static void do_ii_read_lock(struct inode *inode, unsigned int lsc)
+{
+	switch (lsc) {
+	case AuLsc_DI_CHILD:
+		ii_read_lock_child(inode);
+		break;
+	case AuLsc_DI_CHILD2:
+		ii_read_lock_child2(inode);
+		break;
+	case AuLsc_DI_CHILD3:
+		ii_read_lock_child3(inode);
+		break;
+	case AuLsc_DI_PARENT:
+		ii_read_lock_parent(inode);
+		break;
+	case AuLsc_DI_PARENT2:
+		ii_read_lock_parent2(inode);
+		break;
+	case AuLsc_DI_PARENT3:
+		ii_read_lock_parent3(inode);
+		break;
+	default:
+		BUG();
+	}
+}
+
+void di_read_lock(struct dentry *d, int flags, unsigned int lsc)
+{
+	au_rw_read_lock_nested(&au_di(d)->di_rwsem, lsc);
+	if (d->d_inode) {
+		if (au_ftest_lock(flags, IW))
+			do_ii_write_lock(d->d_inode, lsc);
+		else if (au_ftest_lock(flags, IR))
+			do_ii_read_lock(d->d_inode, lsc);
+	}
+}
+
+void di_read_unlock(struct dentry *d, int flags)
+{
+	if (d->d_inode) {
+		if (au_ftest_lock(flags, IW))
+			ii_write_unlock(d->d_inode);
+		else if (au_ftest_lock(flags, IR))
+			ii_read_unlock(d->d_inode);
+	}
+	au_rw_read_unlock(&au_di(d)->di_rwsem);
+}
+
+void di_downgrade_lock(struct dentry *d, int flags)
+{
+	if (d->d_inode && au_ftest_lock(flags, IR))
+		ii_downgrade_lock(d->d_inode);
+	au_rw_dgrade_lock(&au_di(d)->di_rwsem);
+}
+
+void di_write_lock(struct dentry *d, unsigned int lsc)
+{
+	au_rw_write_lock_nested(&au_di(d)->di_rwsem, lsc);
+	if (d->d_inode)
+		do_ii_write_lock(d->d_inode, lsc);
+}
+
+void di_write_unlock(struct dentry *d)
+{
+	if (d->d_inode)
+		ii_write_unlock(d->d_inode);
+	au_rw_write_unlock(&au_di(d)->di_rwsem);
+}
+
+void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir)
+{
+	AuDebugOn(d1 == d2
+		  || d1->d_inode == d2->d_inode
+		  || d1->d_sb != d2->d_sb);
+
+	if (isdir && au_test_subdir(d1, d2)) {
+		di_write_lock_child(d1);
+		di_write_lock_child2(d2);
+	} else {
+		/* there should be no races */
+		di_write_lock_child(d2);
+		di_write_lock_child2(d1);
+	}
+}
+
+void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir)
+{
+	AuDebugOn(d1 == d2
+		  || d1->d_inode == d2->d_inode
+		  || d1->d_sb != d2->d_sb);
+
+	if (isdir && au_test_subdir(d1, d2)) {
+		di_write_lock_parent(d1);
+		di_write_lock_parent2(d2);
+	} else {
+		/* there should be no races */
+		di_write_lock_parent(d2);
+		di_write_lock_parent2(d1);
+	}
+}
+
+void di_write_unlock2(struct dentry *d1, struct dentry *d2)
+{
+	di_write_unlock(d1);
+	if (d1->d_inode == d2->d_inode)
+		au_rw_write_unlock(&au_di(d2)->di_rwsem);
+	else
+		di_write_unlock(d2);
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex)
+{
+	struct dentry *d;
+
+	DiMustAnyLock(dentry);
+
+	if (au_dbstart(dentry) < 0 || bindex < au_dbstart(dentry))
+		return NULL;
+	AuDebugOn(bindex < 0);
+	d = au_di(dentry)->di_hdentry[0 + bindex].hd_dentry;
+	AuDebugOn(d && (atomic_read(&d->d_count) <= 0));
+	return d;
+}
+
+aufs_bindex_t au_dbtail(struct dentry *dentry)
+{
+	aufs_bindex_t bend, bwh;
+
+	bend = au_dbend(dentry);
+	if (0 <= bend) {
+		bwh = au_dbwh(dentry);
+		if (!bwh)
+			return bwh;
+		if (0 < bwh && bwh < bend)
+			return bwh - 1;
+	}
+	return bend;
+}
+
+aufs_bindex_t au_dbtaildir(struct dentry *dentry)
+{
+	aufs_bindex_t bend, bopq;
+
+	bend = au_dbtail(dentry);
+	if (0 <= bend) {
+		bopq = au_dbdiropq(dentry);
+		if (0 <= bopq && bopq < bend)
+			bend = bopq;
+	}
+	return bend;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_set_h_dptr(struct dentry *dentry, aufs_bindex_t bindex,
+		   struct dentry *h_dentry)
+{
+	struct au_hdentry *hd = au_di(dentry)->di_hdentry + bindex;
+
+	DiMustWriteLock(dentry);
+
+	if (hd->hd_dentry)
+		au_hdput(hd);
+	hd->hd_dentry = h_dentry;
+}
+
+void au_update_digen(struct dentry *dentry)
+{
+	atomic_set(&au_di(dentry)->di_generation, au_sigen(dentry->d_sb));
+	/* smp_mb(); */ /* atomic_set */
+}
+
+void au_update_dbrange(struct dentry *dentry, int do_put_zero)
+{
+	struct au_dinfo *dinfo;
+	struct dentry *h_d;
+
+	DiMustWriteLock(dentry);
+
+	dinfo = au_di(dentry);
+	if (!dinfo || dinfo->di_bstart < 0)
+		return;
+
+	if (do_put_zero) {
+		aufs_bindex_t bindex, bend;
+
+		bend = dinfo->di_bend;
+		for (bindex = dinfo->di_bstart; bindex <= bend; bindex++) {
+			h_d = dinfo->di_hdentry[0 + bindex].hd_dentry;
+			if (h_d && !h_d->d_inode)
+				au_set_h_dptr(dentry, bindex, NULL);
+		}
+	}
+
+	dinfo->di_bstart = -1;
+	while (++dinfo->di_bstart <= dinfo->di_bend)
+		if (dinfo->di_hdentry[0 + dinfo->di_bstart].hd_dentry)
+			break;
+	if (dinfo->di_bstart > dinfo->di_bend) {
+		dinfo->di_bstart = -1;
+		dinfo->di_bend = -1;
+		return;
+	}
+
+	dinfo->di_bend++;
+	while (0 <= --dinfo->di_bend)
+		if (dinfo->di_hdentry[0 + dinfo->di_bend].hd_dentry)
+			break;
+	AuDebugOn(dinfo->di_bstart > dinfo->di_bend || dinfo->di_bend < 0);
+}
+
+void au_update_dbstart(struct dentry *dentry)
+{
+	aufs_bindex_t bindex, bend;
+	struct dentry *h_dentry;
+
+	bend = au_dbend(dentry);
+	for (bindex = au_dbstart(dentry); bindex <= bend; bindex++) {
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (!h_dentry)
+			continue;
+		if (h_dentry->d_inode) {
+			au_set_dbstart(dentry, bindex);
+			return;
+		}
+		au_set_h_dptr(dentry, bindex, NULL);
+	}
+}
+
+void au_update_dbend(struct dentry *dentry)
+{
+	aufs_bindex_t bindex, bstart;
+	struct dentry *h_dentry;
+
+	bstart = au_dbstart(dentry);
+	for (bindex = au_dbend(dentry); bindex <= bstart; bindex--) {
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (!h_dentry)
+			continue;
+		if (h_dentry->d_inode) {
+			au_set_dbend(dentry, bindex);
+			return;
+		}
+		au_set_h_dptr(dentry, bindex, NULL);
+	}
+}
+
+int au_find_dbindex(struct dentry *dentry, struct dentry *h_dentry)
+{
+	aufs_bindex_t bindex, bend;
+
+	bend = au_dbend(dentry);
+	for (bindex = au_dbstart(dentry); bindex <= bend; bindex++)
+		if (au_h_dptr(dentry, bindex) == h_dentry)
+			return bindex;
+	return -1;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/dir.c linux-2.6.31.4/fs/aufs/dir.c
--- linux-2.6.31.4.orig/fs/aufs/dir.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/dir.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,538 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * directory operations
+ */
+
+#include <linux/file.h>
+#include <linux/fs_stack.h>
+#include "aufs.h"
+
+void au_add_nlink(struct inode *dir, struct inode *h_dir)
+{
+	AuDebugOn(!S_ISDIR(dir->i_mode) || !S_ISDIR(h_dir->i_mode));
+
+	dir->i_nlink += h_dir->i_nlink - 2;
+	if (h_dir->i_nlink < 2)
+		dir->i_nlink += 2;
+}
+
+void au_sub_nlink(struct inode *dir, struct inode *h_dir)
+{
+	AuDebugOn(!S_ISDIR(dir->i_mode) || !S_ISDIR(h_dir->i_mode));
+
+	dir->i_nlink -= h_dir->i_nlink - 2;
+	if (h_dir->i_nlink < 2)
+		dir->i_nlink -= 2;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int reopen_dir(struct file *file)
+{
+	int err;
+	unsigned int flags;
+	aufs_bindex_t bindex, btail, bstart;
+	struct dentry *dentry, *h_dentry;
+	struct file *h_file;
+
+	/* open all lower dirs */
+	dentry = file->f_dentry;
+	bstart = au_dbstart(dentry);
+	for (bindex = au_fbstart(file); bindex < bstart; bindex++)
+		au_set_h_fptr(file, bindex, NULL);
+	au_set_fbstart(file, bstart);
+
+	btail = au_dbtaildir(dentry);
+	for (bindex = au_fbend(file); btail < bindex; bindex--)
+		au_set_h_fptr(file, bindex, NULL);
+	au_set_fbend(file, btail);
+
+	flags = file->f_flags;
+	for (bindex = bstart; bindex <= btail; bindex++) {
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (!h_dentry)
+			continue;
+		h_file = au_h_fptr(file, bindex);
+		if (h_file)
+			continue;
+
+		h_file = au_h_open(dentry, bindex, flags, file);
+		err = PTR_ERR(h_file);
+		if (IS_ERR(h_file))
+			goto out; /* close all? */
+		au_set_h_fptr(file, bindex, h_file);
+	}
+	au_update_figen(file);
+	/* todo: necessary? */
+	/* file->f_ra = h_file->f_ra; */
+	err = 0;
+
+ out:
+	return err;
+}
+
+static int do_open_dir(struct file *file, int flags)
+{
+	int err;
+	aufs_bindex_t bindex, btail;
+	struct dentry *dentry, *h_dentry;
+	struct file *h_file;
+
+	FiMustWriteLock(file);
+
+	err = 0;
+	dentry = file->f_dentry;
+	au_set_fvdir_cache(file, NULL);
+	au_fi(file)->fi_maintain_plink = 0;
+	file->f_version = dentry->d_inode->i_version;
+	bindex = au_dbstart(dentry);
+	au_set_fbstart(file, bindex);
+	btail = au_dbtaildir(dentry);
+	au_set_fbend(file, btail);
+	for (; !err && bindex <= btail; bindex++) {
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (!h_dentry)
+			continue;
+
+		h_file = au_h_open(dentry, bindex, flags, file);
+		if (IS_ERR(h_file)) {
+			err = PTR_ERR(h_file);
+			break;
+		}
+		au_set_h_fptr(file, bindex, h_file);
+	}
+	au_update_figen(file);
+	/* todo: necessary? */
+	/* file->f_ra = h_file->f_ra; */
+	if (!err)
+		return 0; /* success */
+
+	/* close all */
+	for (bindex = au_fbstart(file); bindex <= btail; bindex++)
+		au_set_h_fptr(file, bindex, NULL);
+	au_set_fbstart(file, -1);
+	au_set_fbend(file, -1);
+	return err;
+}
+
+static int aufs_open_dir(struct inode *inode __maybe_unused,
+			 struct file *file)
+{
+	return au_do_open(file, do_open_dir);
+}
+
+static int aufs_release_dir(struct inode *inode __maybe_unused,
+			    struct file *file)
+{
+	struct au_vdir *vdir_cache;
+	struct super_block *sb;
+	struct au_sbinfo *sbinfo;
+
+	sb = file->f_dentry->d_sb;
+	si_noflush_read_lock(sb);
+	fi_write_lock(file);
+	vdir_cache = au_fvdir_cache(file);
+	if (vdir_cache)
+		au_vdir_free(vdir_cache);
+	if (au_fi(file)->fi_maintain_plink) {
+		sbinfo = au_sbi(sb);
+		/* clear the flag without write-lock */
+		sbinfo->au_si_status &= ~AuSi_MAINTAIN_PLINK;
+		smp_mb();
+		wake_up_all(&sbinfo->si_plink_wq);
+	}
+	fi_write_unlock(file);
+	au_finfo_fin(file);
+	si_read_unlock(sb);
+	return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_do_fsync_dir_no_file(struct dentry *dentry, int datasync)
+{
+	int err;
+	aufs_bindex_t bend, bindex;
+	struct inode *inode;
+	struct super_block *sb;
+
+	err = 0;
+	sb = dentry->d_sb;
+	inode = dentry->d_inode;
+	IMustLock(inode);
+	bend = au_dbend(dentry);
+	for (bindex = au_dbstart(dentry); !err && bindex <= bend; bindex++) {
+		struct path h_path;
+		struct inode *h_inode;
+
+		if (au_test_ro(sb, bindex, inode))
+			continue;
+		h_path.dentry = au_h_dptr(dentry, bindex);
+		if (!h_path.dentry)
+			continue;
+		h_inode = h_path.dentry->d_inode;
+		if (!h_inode)
+			continue;
+
+		/* no mnt_want_write() */
+		/* cf. fs/nsfd/vfs.c and fs/nfsd/nfs4recover.c */
+		/* todo: inotiry fired? */
+		h_path.mnt = au_sbr_mnt(sb, bindex);
+		mutex_lock(&h_inode->i_mutex);
+		err = filemap_fdatawrite(h_inode->i_mapping);
+		AuDebugOn(!h_inode->i_fop);
+		if (!err && h_inode->i_fop->fsync)
+			err = h_inode->i_fop->fsync(NULL, h_path.dentry,
+						    datasync);
+		if (!err)
+			err = filemap_fdatawrite(h_inode->i_mapping);
+		if (!err)
+			vfsub_update_h_iattr(&h_path, /*did*/NULL); /*ignore*/
+		mutex_unlock(&h_inode->i_mutex);
+	}
+
+	return err;
+}
+
+static int au_do_fsync_dir(struct file *file, int datasync)
+{
+	int err;
+	aufs_bindex_t bend, bindex;
+	struct file *h_file;
+	struct super_block *sb;
+	struct inode *inode;
+	struct mutex *h_mtx;
+
+	err = au_reval_and_lock_fdi(file, reopen_dir, /*wlock*/1);
+	if (unlikely(err))
+		goto out;
+
+	sb = file->f_dentry->d_sb;
+	inode = file->f_dentry->d_inode;
+	bend = au_fbend(file);
+	for (bindex = au_fbstart(file); !err && bindex <= bend; bindex++) {
+		h_file = au_h_fptr(file, bindex);
+		if (!h_file || au_test_ro(sb, bindex, inode))
+			continue;
+
+		err = vfs_fsync(h_file, h_file->f_dentry, datasync);
+		if (!err) {
+			h_mtx = &h_file->f_dentry->d_inode->i_mutex;
+			mutex_lock(h_mtx);
+			vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL);
+			/*ignore*/
+			mutex_unlock(h_mtx);
+		}
+	}
+
+ out:
+	return err;
+}
+
+/*
+ * @file may be NULL
+ */
+static int aufs_fsync_dir(struct file *file, struct dentry *dentry,
+			  int datasync)
+{
+	int err;
+	struct super_block *sb;
+
+	IMustLock(dentry->d_inode);
+
+	err = 0;
+	sb = dentry->d_sb;
+	si_noflush_read_lock(sb);
+	if (file)
+		err = au_do_fsync_dir(file, datasync);
+	else {
+		di_write_lock_child(dentry);
+		err = au_do_fsync_dir_no_file(dentry, datasync);
+	}
+	au_cpup_attr_timesizes(dentry->d_inode);
+	di_write_unlock(dentry);
+	if (file)
+		fi_write_unlock(file);
+
+	si_read_unlock(sb);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int aufs_readdir(struct file *file, void *dirent, filldir_t filldir)
+{
+	int err;
+	struct dentry *dentry;
+	struct inode *inode;
+	struct super_block *sb;
+
+	dentry = file->f_dentry;
+	inode = dentry->d_inode;
+	IMustLock(inode);
+
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_fdi(file, reopen_dir, /*wlock*/1);
+	if (unlikely(err))
+		goto out;
+	err = au_vdir_init(file);
+	di_downgrade_lock(dentry, AuLock_IR);
+	if (unlikely(err))
+		goto out_unlock;
+
+	if (!au_test_nfsd(current)) {
+		err = au_vdir_fill_de(file, dirent, filldir);
+		fsstack_copy_attr_atime(inode,
+					au_h_iptr(inode, au_ibstart(inode)));
+	} else {
+		/*
+		 * nfsd filldir may call lookup_one_len(), vfs_getattr(),
+		 * encode_fh() and others.
+		 */
+		struct inode *h_inode = au_h_iptr(inode, au_ibstart(inode));
+
+		di_read_unlock(dentry, AuLock_IR);
+		si_read_unlock(sb);
+		lockdep_off();
+		err = au_vdir_fill_de(file, dirent, filldir);
+		lockdep_on();
+		fsstack_copy_attr_atime(inode, h_inode);
+		fi_write_unlock(file);
+
+		AuTraceErr(err);
+		return err;
+	}
+
+ out_unlock:
+	di_read_unlock(dentry, AuLock_IR);
+	fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+#define AuTestEmpty_WHONLY	1
+#define AuTestEmpty_CALLED	(1 << 1)
+#define AuTestEmpty_SHWH	(1 << 2)
+#define au_ftest_testempty(flags, name)	((flags) & AuTestEmpty_##name)
+#define au_fset_testempty(flags, name)	{ (flags) |= AuTestEmpty_##name; }
+#define au_fclr_testempty(flags, name)	{ (flags) &= ~AuTestEmpty_##name; }
+
+#ifndef CONFIG_AUFS_SHWH
+#undef AuTestEmpty_SHWH
+#define AuTestEmpty_SHWH	0
+#endif
+
+struct test_empty_arg {
+	struct au_nhash whlist;
+	unsigned int flags;
+	int err;
+	aufs_bindex_t bindex;
+};
+
+static int test_empty_cb(void *__arg, const char *__name, int namelen,
+			 loff_t offset __maybe_unused, u64 ino,
+			 unsigned int d_type)
+{
+	struct test_empty_arg *arg = __arg;
+	char *name = (void *)__name;
+
+	arg->err = 0;
+	au_fset_testempty(arg->flags, CALLED);
+	/* smp_mb(); */
+	if (name[0] == '.'
+	    && (namelen == 1 || (name[1] == '.' && namelen == 2)))
+		goto out; /* success */
+
+	if (namelen <= AUFS_WH_PFX_LEN
+	    || memcmp(name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
+		if (au_ftest_testempty(arg->flags, WHONLY)
+		    && !au_nhash_test_known_wh(&arg->whlist, name, namelen))
+			arg->err = -ENOTEMPTY;
+		goto out;
+	}
+
+	name += AUFS_WH_PFX_LEN;
+	namelen -= AUFS_WH_PFX_LEN;
+	if (!au_nhash_test_known_wh(&arg->whlist, name, namelen))
+		arg->err = au_nhash_append_wh
+			(&arg->whlist, name, namelen, ino, d_type, arg->bindex,
+			 au_ftest_testempty(arg->flags, SHWH));
+
+ out:
+	/* smp_mb(); */
+	AuTraceErr(arg->err);
+	return arg->err;
+}
+
+static int do_test_empty(struct dentry *dentry, struct test_empty_arg *arg)
+{
+	int err;
+	struct file *h_file;
+
+	h_file = au_h_open(dentry, arg->bindex,
+			   O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_LARGEFILE,
+			   /*file*/NULL);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out;
+
+	err = 0;
+	if (!au_opt_test(au_mntflags(dentry->d_sb), UDBA_NONE)
+	    && !h_file->f_dentry->d_inode->i_nlink)
+		goto out_put;
+
+	do {
+		arg->err = 0;
+		au_fclr_testempty(arg->flags, CALLED);
+		/* smp_mb(); */
+		err = vfsub_readdir(h_file, test_empty_cb, arg);
+		if (err >= 0)
+			err = arg->err;
+	} while (!err && au_ftest_testempty(arg->flags, CALLED));
+
+ out_put:
+	fput(h_file);
+	au_sbr_put(dentry->d_sb, arg->bindex);
+ out:
+	return err;
+}
+
+struct do_test_empty_args {
+	int *errp;
+	struct dentry *dentry;
+	struct test_empty_arg *arg;
+};
+
+static void call_do_test_empty(void *args)
+{
+	struct do_test_empty_args *a = args;
+	*a->errp = do_test_empty(a->dentry, a->arg);
+}
+
+static int sio_test_empty(struct dentry *dentry, struct test_empty_arg *arg)
+{
+	int err, wkq_err;
+	struct dentry *h_dentry;
+	struct inode *h_inode;
+
+	h_dentry = au_h_dptr(dentry, arg->bindex);
+	h_inode = h_dentry->d_inode;
+	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+	err = au_test_h_perm_sio(h_inode, MAY_EXEC | MAY_READ);
+	mutex_unlock(&h_inode->i_mutex);
+	if (!err)
+		err = do_test_empty(dentry, arg);
+	else {
+		struct do_test_empty_args args = {
+			.errp	= &err,
+			.dentry	= dentry,
+			.arg	= arg
+		};
+		unsigned int flags = arg->flags;
+
+		wkq_err = au_wkq_wait(call_do_test_empty, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+		arg->flags = flags;
+	}
+
+	return err;
+}
+
+int au_test_empty_lower(struct dentry *dentry)
+{
+	int err;
+	aufs_bindex_t bindex, bstart, btail;
+	struct test_empty_arg arg;
+
+	SiMustAnyLock(dentry->d_sb);
+
+	err = au_nhash_alloc(&arg.whlist, au_sbi(dentry->d_sb)->si_rdhash,
+			     GFP_NOFS);
+	if (unlikely(err))
+		goto out;
+
+	bstart = au_dbstart(dentry);
+	arg.flags = 0;
+	if (au_opt_test(au_mntflags(dentry->d_sb), SHWH))
+		au_fset_testempty(arg.flags, SHWH);
+	arg.bindex = bstart;
+	err = do_test_empty(dentry, &arg);
+	if (unlikely(err))
+		goto out_whlist;
+
+	au_fset_testempty(arg.flags, WHONLY);
+	btail = au_dbtaildir(dentry);
+	for (bindex = bstart + 1; !err && bindex <= btail; bindex++) {
+		struct dentry *h_dentry;
+
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (h_dentry && h_dentry->d_inode) {
+			arg.bindex = bindex;
+			err = do_test_empty(dentry, &arg);
+		}
+	}
+
+ out_whlist:
+	au_nhash_wh_free(&arg.whlist);
+ out:
+	return err;
+}
+
+int au_test_empty(struct dentry *dentry, struct au_nhash *whlist)
+{
+	int err;
+	struct test_empty_arg arg;
+	aufs_bindex_t bindex, btail;
+
+	err = 0;
+	arg.whlist = *whlist;
+	arg.flags = AuTestEmpty_WHONLY;
+	if (au_opt_test(au_mntflags(dentry->d_sb), SHWH))
+		au_fset_testempty(arg.flags, SHWH);
+	btail = au_dbtaildir(dentry);
+	for (bindex = au_dbstart(dentry); !err && bindex <= btail; bindex++) {
+		struct dentry *h_dentry;
+
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (h_dentry && h_dentry->d_inode) {
+			arg.bindex = bindex;
+			err = sio_test_empty(dentry, &arg);
+		}
+	}
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+const struct file_operations aufs_dir_fop = {
+	.read		= generic_read_dir,
+	.readdir	= aufs_readdir,
+	.unlocked_ioctl	= aufs_ioctl_dir,
+	.open		= aufs_open_dir,
+	.release	= aufs_release_dir,
+	.flush		= aufs_flush,
+	.fsync		= aufs_fsync_dir
+};
diff -Nur linux-2.6.31.4.orig/fs/aufs/dir.h linux-2.6.31.4/fs/aufs/dir.h
--- linux-2.6.31.4.orig/fs/aufs/dir.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/dir.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * directory operations
+ */
+
+#ifndef __AUFS_DIR_H__
+#define __AUFS_DIR_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/aufs_type.h>
+
+/* ---------------------------------------------------------------------- */
+
+/* need to be faster and smaller */
+
+struct au_nhash {
+	unsigned int		nh_num;
+	struct hlist_head	*nh_head;
+};
+
+struct au_vdir_destr {
+	unsigned char	len;
+	unsigned char	name[0];
+} __packed;
+
+struct au_vdir_dehstr {
+	struct hlist_node	hash;
+	struct au_vdir_destr	*str;
+};
+
+struct au_vdir_de {
+	ino_t			de_ino;
+	unsigned char		de_type;
+	/* caution: packed */
+	struct au_vdir_destr	de_str;
+} __packed;
+
+struct au_vdir_wh {
+	struct hlist_node	wh_hash;
+#ifdef CONFIG_AUFS_SHWH
+	ino_t			wh_ino;
+	aufs_bindex_t		wh_bindex;
+	unsigned char		wh_type;
+#else
+	aufs_bindex_t		wh_bindex;
+#endif
+	/* caution: packed */
+	struct au_vdir_destr	wh_str;
+} __packed;
+
+union au_vdir_deblk_p {
+	unsigned char		*deblk;
+	struct au_vdir_de	*de;
+};
+
+struct au_vdir {
+	unsigned char	**vd_deblk;
+	unsigned long	vd_nblk;
+	struct {
+		unsigned long		ul;
+		union au_vdir_deblk_p	p;
+	} vd_last;
+
+	unsigned long	vd_version;
+	unsigned int	vd_deblk_sz;
+	unsigned long	vd_jiffy;
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* dir.c */
+extern const struct file_operations aufs_dir_fop;
+void au_add_nlink(struct inode *dir, struct inode *h_dir);
+void au_sub_nlink(struct inode *dir, struct inode *h_dir);
+int au_test_empty_lower(struct dentry *dentry);
+int au_test_empty(struct dentry *dentry, struct au_nhash *whlist);
+
+/* vdir.c */
+int au_nhash_alloc(struct au_nhash *nhash, unsigned int num_hash, gfp_t gfp);
+void au_nhash_wh_free(struct au_nhash *whlist);
+int au_nhash_test_longer_wh(struct au_nhash *whlist, aufs_bindex_t btgt,
+			    int limit);
+int au_nhash_test_known_wh(struct au_nhash *whlist, char *name, int nlen);
+int au_nhash_append_wh(struct au_nhash *whlist, char *name, int nlen, ino_t ino,
+		       unsigned int d_type, aufs_bindex_t bindex,
+		       unsigned char shwh);
+void au_vdir_free(struct au_vdir *vdir);
+int au_vdir_init(struct file *file);
+int au_vdir_fill_de(struct file *file, void *dirent, filldir_t filldir);
+
+/* ioctl.c */
+long aufs_ioctl_dir(struct file *file, unsigned int cmd, unsigned long arg);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_DIR_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/export.c linux-2.6.31.4/fs/aufs/export.c
--- linux-2.6.31.4.orig/fs/aufs/export.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/export.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,745 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * export via nfs
+ */
+
+#include <linux/exportfs.h>
+#include <linux/file.h>
+#include <linux/mnt_namespace.h>
+#include <linux/namei.h>
+#include <linux/random.h>
+#include "aufs.h"
+
+union conv {
+#ifdef CONFIG_AUFS_INO_T_64
+	__u32 a[2];
+#else
+	__u32 a[1];
+#endif
+	ino_t ino;
+};
+
+static ino_t decode_ino(__u32 *a)
+{
+	union conv u;
+
+	BUILD_BUG_ON(sizeof(u.ino) != sizeof(u.a));
+	u.a[0] = a[0];
+#ifdef CONFIG_AUFS_INO_T_64
+	u.a[1] = a[1];
+#endif
+	return u.ino;
+}
+
+static void encode_ino(__u32 *a, ino_t ino)
+{
+	union conv u;
+
+	u.ino = ino;
+	a[0] = u.a[0];
+#ifdef CONFIG_AUFS_INO_T_64
+	a[1] = u.a[1];
+#endif
+}
+
+/* NFS file handle */
+enum {
+	Fh_br_id,
+	Fh_sigen,
+#ifdef CONFIG_AUFS_INO_T_64
+	/* support 64bit inode number */
+	Fh_ino1,
+	Fh_ino2,
+	Fh_dir_ino1,
+	Fh_dir_ino2,
+#else
+	Fh_ino1,
+	Fh_dir_ino1,
+#endif
+	Fh_igen,
+	Fh_h_type,
+	Fh_tail,
+
+	Fh_ino = Fh_ino1,
+	Fh_dir_ino = Fh_dir_ino1
+};
+
+static int au_test_anon(struct dentry *dentry)
+{
+	return !!(dentry->d_flags & DCACHE_DISCONNECTED);
+}
+
+/* ---------------------------------------------------------------------- */
+/* inode generation external table */
+
+int au_xigen_inc(struct inode *inode)
+{
+	int err;
+	loff_t pos;
+	ssize_t sz;
+	__u32 igen;
+	struct super_block *sb;
+	struct au_sbinfo *sbinfo;
+
+	err = 0;
+	sb = inode->i_sb;
+	sbinfo = au_sbi(sb);
+	/*
+	 * temporary workaround for escaping from SiMustAnyLock() in
+	 * au_mntflags(), since this function is called from au_iinfo_fin().
+	 */
+	if (unlikely(!au_opt_test(sbinfo->si_mntflags, XINO)))
+		goto out;
+
+	pos = inode->i_ino;
+	pos *= sizeof(igen);
+	igen = inode->i_generation + 1;
+	sz = xino_fwrite(sbinfo->si_xwrite, sbinfo->si_xigen, &igen,
+			 sizeof(igen), &pos);
+	if (sz == sizeof(igen))
+		goto out; /* success */
+
+	err = sz;
+	if (unlikely(sz >= 0)) {
+		err = -EIO;
+		AuIOErr("xigen error (%zd)\n", sz);
+	}
+
+ out:
+	return err;
+}
+
+int au_xigen_new(struct inode *inode)
+{
+	int err;
+	loff_t pos;
+	ssize_t sz;
+	struct super_block *sb;
+	struct au_sbinfo *sbinfo;
+	struct file *file;
+
+	err = 0;
+	/* todo: dirty, at mount time */
+	if (inode->i_ino == AUFS_ROOT_INO)
+		goto out;
+	sb = inode->i_sb;
+	SiMustAnyLock(sb);
+	if (unlikely(!au_opt_test(au_mntflags(sb), XINO)))
+		goto out;
+
+	err = -EFBIG;
+	pos = inode->i_ino;
+	if (unlikely(au_loff_max / sizeof(inode->i_generation) - 1 < pos)) {
+		AuIOErr1("too large i%lld\n", pos);
+		goto out;
+	}
+	pos *= sizeof(inode->i_generation);
+
+	err = 0;
+	sbinfo = au_sbi(sb);
+	file = sbinfo->si_xigen;
+	BUG_ON(!file);
+
+	if (i_size_read(file->f_dentry->d_inode)
+	    < pos + sizeof(inode->i_generation)) {
+		inode->i_generation = atomic_inc_return(&sbinfo->si_xigen_next);
+		sz = xino_fwrite(sbinfo->si_xwrite, file, &inode->i_generation,
+				 sizeof(inode->i_generation), &pos);
+	} else
+		sz = xino_fread(sbinfo->si_xread, file, &inode->i_generation,
+				sizeof(inode->i_generation), &pos);
+	if (sz == sizeof(inode->i_generation))
+		goto out; /* success */
+
+	err = sz;
+	if (unlikely(sz >= 0)) {
+		err = -EIO;
+		AuIOErr("xigen error (%zd)\n", sz);
+	}
+
+ out:
+	return err;
+}
+
+int au_xigen_set(struct super_block *sb, struct file *base)
+{
+	int err;
+	struct au_sbinfo *sbinfo;
+	struct file *file;
+
+	SiMustWriteLock(sb);
+
+	sbinfo = au_sbi(sb);
+	file = au_xino_create2(base, sbinfo->si_xigen);
+	err = PTR_ERR(file);
+	if (IS_ERR(file))
+		goto out;
+	err = 0;
+	if (sbinfo->si_xigen)
+		fput(sbinfo->si_xigen);
+	sbinfo->si_xigen = file;
+
+ out:
+	return err;
+}
+
+void au_xigen_clr(struct super_block *sb)
+{
+	struct au_sbinfo *sbinfo;
+
+	SiMustWriteLock(sb);
+
+	sbinfo = au_sbi(sb);
+	if (sbinfo->si_xigen) {
+		fput(sbinfo->si_xigen);
+		sbinfo->si_xigen = NULL;
+	}
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct dentry *decode_by_ino(struct super_block *sb, ino_t ino,
+				    ino_t dir_ino)
+{
+	struct dentry *dentry, *d;
+	struct inode *inode;
+	unsigned int sigen;
+
+	dentry = NULL;
+	inode = ilookup(sb, ino);
+	if (!inode)
+		goto out;
+
+	dentry = ERR_PTR(-ESTALE);
+	sigen = au_sigen(sb);
+	if (unlikely(is_bad_inode(inode)
+		     || IS_DEADDIR(inode)
+		     || sigen != au_iigen(inode)))
+		goto out_iput;
+
+	dentry = NULL;
+	if (!dir_ino || S_ISDIR(inode->i_mode))
+		dentry = d_find_alias(inode);
+	else {
+		spin_lock(&dcache_lock);
+		list_for_each_entry(d, &inode->i_dentry, d_alias)
+			if (!au_test_anon(d)
+			    && d->d_parent->d_inode->i_ino == dir_ino) {
+				dentry = dget_locked(d);
+				break;
+			}
+		spin_unlock(&dcache_lock);
+	}
+	if (unlikely(dentry && sigen != au_digen(dentry))) {
+		dput(dentry);
+		dentry = ERR_PTR(-ESTALE);
+	}
+
+ out_iput:
+	iput(inode);
+ out:
+	return dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* todo: dirty? */
+/* if exportfs_decode_fh() passed vfsmount*, we could be happy */
+static struct vfsmount *au_mnt_get(struct super_block *sb)
+{
+	struct mnt_namespace *ns;
+	struct vfsmount *pos, *mnt;
+
+	spin_lock(&vfsmount_lock);
+	/* no get/put ?? */
+	AuDebugOn(!current->nsproxy);
+	ns = current->nsproxy->mnt_ns;
+	AuDebugOn(!ns);
+	mnt = NULL;
+	/* the order (reverse) will not be a problem */
+	list_for_each_entry(pos, &ns->list, mnt_list)
+		if (pos->mnt_sb == sb) {
+			mnt = mntget(pos);
+			break;
+		}
+	spin_unlock(&vfsmount_lock);
+	AuDebugOn(!mnt);
+
+	return mnt;
+}
+
+struct au_nfsd_si_lock {
+	const unsigned int sigen;
+	const aufs_bindex_t br_id;
+	unsigned char force_lock;
+};
+
+static aufs_bindex_t si_nfsd_read_lock(struct super_block *sb,
+				       struct au_nfsd_si_lock *nsi_lock)
+{
+	aufs_bindex_t bindex;
+
+	si_read_lock(sb, AuLock_FLUSH);
+
+	/* branch id may be wrapped around */
+	bindex = au_br_index(sb, nsi_lock->br_id);
+	if (bindex >= 0 && nsi_lock->sigen + AUFS_BRANCH_MAX > au_sigen(sb))
+		goto out; /* success */
+
+	if (!nsi_lock->force_lock)
+		si_read_unlock(sb);
+	bindex = -1;
+
+ out:
+	return bindex;
+}
+
+struct find_name_by_ino {
+	int called, found;
+	ino_t ino;
+	char *name;
+	int namelen;
+};
+
+static int
+find_name_by_ino(void *arg, const char *name, int namelen, loff_t offset,
+		 u64 ino, unsigned int d_type)
+{
+	struct find_name_by_ino *a = arg;
+
+	a->called++;
+	if (a->ino != ino)
+		return 0;
+
+	memcpy(a->name, name, namelen);
+	a->namelen = namelen;
+	a->found = 1;
+	return 1;
+}
+
+static struct dentry *au_lkup_by_ino(struct path *path, ino_t ino,
+				     struct au_nfsd_si_lock *nsi_lock)
+{
+	struct dentry *dentry, *parent;
+	struct file *file;
+	struct inode *dir;
+	struct find_name_by_ino arg;
+	int err;
+
+	parent = path->dentry;
+	if (nsi_lock)
+		si_read_unlock(parent->d_sb);
+	path_get(path);
+	file = dentry_open(parent, path->mnt, au_dir_roflags, current_cred());
+	dentry = (void *)file;
+	if (IS_ERR(file))
+		goto out;
+
+	dentry = ERR_PTR(-ENOMEM);
+	arg.name = __getname();
+	if (unlikely(!arg.name))
+		goto out_file;
+	arg.ino = ino;
+	arg.found = 0;
+	do {
+		arg.called = 0;
+		/* smp_mb(); */
+		err = vfsub_readdir(file, find_name_by_ino, &arg);
+	} while (!err && !arg.found && arg.called);
+	dentry = ERR_PTR(err);
+	if (unlikely(err))
+		goto out_name;
+	dentry = ERR_PTR(-ENOENT);
+	if (!arg.found)
+		goto out_name;
+
+	/* do not call au_lkup_one() */
+	dir = parent->d_inode;
+	mutex_lock(&dir->i_mutex);
+	dentry = vfsub_lookup_one_len(arg.name, parent, arg.namelen);
+	mutex_unlock(&dir->i_mutex);
+	AuTraceErrPtr(dentry);
+	if (IS_ERR(dentry))
+		goto out_name;
+	AuDebugOn(au_test_anon(dentry));
+	if (unlikely(!dentry->d_inode)) {
+		dput(dentry);
+		dentry = ERR_PTR(-ENOENT);
+	}
+
+ out_name:
+	__putname(arg.name);
+ out_file:
+	fput(file);
+ out:
+	if (unlikely(nsi_lock
+		     && si_nfsd_read_lock(parent->d_sb, nsi_lock) < 0))
+		if (!IS_ERR(dentry)) {
+			dput(dentry);
+			dentry = ERR_PTR(-ESTALE);
+		}
+	AuTraceErrPtr(dentry);
+	return dentry;
+}
+
+static struct dentry *decode_by_dir_ino(struct super_block *sb, ino_t ino,
+					ino_t dir_ino,
+					struct au_nfsd_si_lock *nsi_lock)
+{
+	struct dentry *dentry;
+	struct path path;
+
+	if (dir_ino != AUFS_ROOT_INO) {
+		path.dentry = decode_by_ino(sb, dir_ino, 0);
+		dentry = path.dentry;
+		if (!path.dentry || IS_ERR(path.dentry))
+			goto out;
+		AuDebugOn(au_test_anon(path.dentry));
+	} else
+		path.dentry = dget(sb->s_root);
+
+	path.mnt = au_mnt_get(sb);
+	dentry = au_lkup_by_ino(&path, ino, nsi_lock);
+	path_put(&path);
+
+ out:
+	AuTraceErrPtr(dentry);
+	return dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int h_acceptable(void *expv, struct dentry *dentry)
+{
+	return 1;
+}
+
+static char *au_build_path(struct dentry *h_parent, struct path *h_rootpath,
+			   char *buf, int len, struct super_block *sb)
+{
+	char *p;
+	int n;
+	struct path path;
+
+	p = d_path(h_rootpath, buf, len);
+	if (IS_ERR(p))
+		goto out;
+	n = strlen(p);
+
+	path.mnt = h_rootpath->mnt;
+	path.dentry = h_parent;
+	p = d_path(&path, buf, len);
+	if (IS_ERR(p))
+		goto out;
+	if (n != 1)
+		p += n;
+
+	path.mnt = au_mnt_get(sb);
+	path.dentry = sb->s_root;
+	p = d_path(&path, buf, len - strlen(p));
+	mntput(path.mnt);
+	if (IS_ERR(p))
+		goto out;
+	if (n != 1)
+		p[strlen(p)] = '/';
+
+ out:
+	AuTraceErrPtr(p);
+	return p;
+}
+
+static
+struct dentry *decode_by_path(struct super_block *sb, aufs_bindex_t bindex,
+			      ino_t ino, __u32 *fh, int fh_len,
+			      struct au_nfsd_si_lock *nsi_lock)
+{
+	struct dentry *dentry, *h_parent, *root;
+	struct super_block *h_sb;
+	char *pathname, *p;
+	struct vfsmount *h_mnt;
+	struct au_branch *br;
+	int err;
+	struct path path;
+
+	br = au_sbr(sb, bindex);
+	/* au_br_get(br); */
+	h_mnt = br->br_mnt;
+	h_sb = h_mnt->mnt_sb;
+	/* todo: call lower fh_to_dentry()? fh_to_parent()? */
+	h_parent = exportfs_decode_fh(h_mnt, (void *)(fh + Fh_tail),
+				      fh_len - Fh_tail, fh[Fh_h_type],
+				      h_acceptable, /*context*/NULL);
+	dentry = h_parent;
+	if (unlikely(!h_parent || IS_ERR(h_parent))) {
+		AuWarn1("%s decode_fh failed, %ld\n",
+			au_sbtype(h_sb), PTR_ERR(h_parent));
+		goto out;
+	}
+	dentry = NULL;
+	if (unlikely(au_test_anon(h_parent))) {
+		AuWarn1("%s decode_fh returned a disconnected dentry\n",
+			au_sbtype(h_sb));
+		goto out_h_parent;
+	}
+
+	dentry = ERR_PTR(-ENOMEM);
+	pathname = (void *)__get_free_page(GFP_NOFS);
+	if (unlikely(!pathname))
+		goto out_h_parent;
+
+	root = sb->s_root;
+	path.mnt = h_mnt;
+	di_read_lock_parent(root, !AuLock_IR);
+	path.dentry = au_h_dptr(root, bindex);
+	di_read_unlock(root, !AuLock_IR);
+	p = au_build_path(h_parent, &path, pathname, PAGE_SIZE, sb);
+	dentry = (void *)p;
+	if (IS_ERR(p))
+		goto out_pathname;
+
+	si_read_unlock(sb);
+	err = vfsub_kern_path(p, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
+	dentry = ERR_PTR(err);
+	if (unlikely(err))
+		goto out_relock;
+
+	dentry = ERR_PTR(-ENOENT);
+	AuDebugOn(au_test_anon(path.dentry));
+	if (unlikely(!path.dentry->d_inode))
+		goto out_path;
+
+	if (ino != path.dentry->d_inode->i_ino)
+		dentry = au_lkup_by_ino(&path, ino, /*nsi_lock*/NULL);
+	else
+		dentry = dget(path.dentry);
+
+ out_path:
+	path_put(&path);
+ out_relock:
+	if (unlikely(si_nfsd_read_lock(sb, nsi_lock) < 0))
+		if (!IS_ERR(dentry)) {
+			dput(dentry);
+			dentry = ERR_PTR(-ESTALE);
+		}
+ out_pathname:
+	free_page((unsigned long)pathname);
+ out_h_parent:
+	dput(h_parent);
+ out:
+	/* au_br_put(br); */
+	AuTraceErrPtr(dentry);
+	return dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct dentry *
+aufs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
+		  int fh_type)
+{
+	struct dentry *dentry;
+	__u32 *fh = fid->raw;
+	ino_t ino, dir_ino;
+	aufs_bindex_t bindex;
+	struct au_nfsd_si_lock nsi_lock = {
+		.sigen		= fh[Fh_sigen],
+		.br_id		= fh[Fh_br_id],
+		.force_lock	= 0
+	};
+
+	AuDebugOn(fh_len < Fh_tail);
+
+	dentry = ERR_PTR(-ESTALE);
+	/* branch id may be wrapped around */
+	bindex = si_nfsd_read_lock(sb, &nsi_lock);
+	if (unlikely(bindex < 0))
+		goto out;
+	nsi_lock.force_lock = 1;
+
+	/* is this inode still cached? */
+	ino = decode_ino(fh + Fh_ino);
+	AuDebugOn(ino == AUFS_ROOT_INO);
+	dir_ino = decode_ino(fh + Fh_dir_ino);
+	dentry = decode_by_ino(sb, ino, dir_ino);
+	if (IS_ERR(dentry))
+		goto out_unlock;
+	if (dentry)
+		goto accept;
+
+	/* is the parent dir cached? */
+	dentry = decode_by_dir_ino(sb, ino, dir_ino, &nsi_lock);
+	if (IS_ERR(dentry))
+		goto out_unlock;
+	if (dentry)
+		goto accept;
+
+	/* lookup path */
+	dentry = decode_by_path(sb, bindex, ino, fh, fh_len, &nsi_lock);
+	if (IS_ERR(dentry))
+		goto out_unlock;
+	if (unlikely(!dentry))
+		/* todo?: make it ESTALE */
+		goto out_unlock;
+
+ accept:
+	if (dentry->d_inode->i_generation == fh[Fh_igen])
+		goto out_unlock; /* success */
+
+	dput(dentry);
+	dentry = ERR_PTR(-ESTALE);
+ out_unlock:
+	si_read_unlock(sb);
+ out:
+	AuTraceErrPtr(dentry);
+	return dentry;
+}
+
+#if 0 /* reserved for future use */
+/* support subtreecheck option */
+static struct dentry *aufs_fh_to_parent(struct super_block *sb, struct fid *fid,
+					int fh_len, int fh_type)
+{
+	struct dentry *parent;
+	__u32 *fh = fid->raw;
+	ino_t dir_ino;
+
+	dir_ino = decode_ino(fh + Fh_dir_ino);
+	parent = decode_by_ino(sb, dir_ino, 0);
+	if (IS_ERR(parent))
+		goto out;
+	if (!parent)
+		parent = decode_by_path(sb, au_br_index(sb, fh[Fh_br_id]),
+					dir_ino, fh, fh_len);
+
+ out:
+	AuTraceErrPtr(parent);
+	return parent;
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+static int aufs_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len,
+			  int connectable)
+{
+	int err;
+	aufs_bindex_t bindex, bend;
+	struct super_block *sb, *h_sb;
+	struct inode *inode;
+	struct dentry *parent, *h_parent;
+	struct au_branch *br;
+
+	AuDebugOn(au_test_anon(dentry));
+
+	parent = NULL;
+	err = -ENOSPC;
+	if (unlikely(*max_len <= Fh_tail)) {
+		AuWarn1("NFSv2 client (max_len %d)?\n", *max_len);
+		goto out;
+	}
+
+	err = FILEID_ROOT;
+	if (IS_ROOT(dentry)) {
+		AuDebugOn(dentry->d_inode->i_ino != AUFS_ROOT_INO);
+		goto out;
+	}
+
+	err = -EIO;
+	h_parent = NULL;
+	sb = dentry->d_sb;
+	aufs_read_lock(dentry, AuLock_FLUSH | AuLock_IR);
+	parent = dget_parent(dentry);
+	di_read_lock_parent(parent, !AuLock_IR);
+	inode = dentry->d_inode;
+	AuDebugOn(!inode);
+#ifdef CONFIG_AUFS_DEBUG
+	if (unlikely(!au_opt_test(au_mntflags(sb), XINO)))
+		AuWarn1("NFS-exporting requires xino\n");
+#endif
+
+	bend = au_dbtaildir(parent);
+	for (bindex = au_dbstart(parent); bindex <= bend; bindex++) {
+		h_parent = au_h_dptr(parent, bindex);
+		if (h_parent) {
+			dget(h_parent);
+			break;
+		}
+	}
+	if (unlikely(!h_parent))
+		goto out_unlock;
+
+	err = -EPERM;
+	br = au_sbr(sb, bindex);
+	h_sb = br->br_mnt->mnt_sb;
+	if (unlikely(!h_sb->s_export_op)) {
+		AuErr1("%s branch is not exportable\n", au_sbtype(h_sb));
+		goto out_dput;
+	}
+
+	fh[Fh_br_id] = br->br_id;
+	fh[Fh_sigen] = au_sigen(sb);
+	encode_ino(fh + Fh_ino, inode->i_ino);
+	encode_ino(fh + Fh_dir_ino, parent->d_inode->i_ino);
+	fh[Fh_igen] = inode->i_generation;
+
+	*max_len -= Fh_tail;
+	fh[Fh_h_type] = exportfs_encode_fh(h_parent, (void *)(fh + Fh_tail),
+					   max_len,
+					   /*connectable or subtreecheck*/0);
+	err = fh[Fh_h_type];
+	*max_len += Fh_tail;
+	/* todo: macros? */
+	if (err != 255)
+		err = 99;
+	else
+		AuWarn1("%s encode_fh failed\n", au_sbtype(h_sb));
+
+ out_dput:
+	dput(h_parent);
+ out_unlock:
+	di_read_unlock(parent, !AuLock_IR);
+	dput(parent);
+	aufs_read_unlock(dentry, AuLock_IR);
+ out:
+	if (unlikely(err < 0))
+		err = 255;
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct export_operations aufs_export_op = {
+	.fh_to_dentry	= aufs_fh_to_dentry,
+	/* .fh_to_parent	= aufs_fh_to_parent, */
+	.encode_fh	= aufs_encode_fh
+};
+
+void au_export_init(struct super_block *sb)
+{
+	struct au_sbinfo *sbinfo;
+	__u32 u;
+
+	sb->s_export_op = &aufs_export_op;
+	sbinfo = au_sbi(sb);
+	sbinfo->si_xigen = NULL;
+	get_random_bytes(&u, sizeof(u));
+	BUILD_BUG_ON(sizeof(u) != sizeof(int));
+	atomic_set(&sbinfo->si_xigen_next, u);
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/file.c linux-2.6.31.4/fs/aufs/file.c
--- linux-2.6.31.4.orig/fs/aufs/file.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/file.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,578 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * handling file/dir, and address_space operation
+ */
+
+#include <linux/file.h>
+#include <linux/fsnotify.h>
+#include <linux/namei.h>
+#include <linux/pagemap.h>
+#include "aufs.h"
+
+/*
+ * a dirty trick for handling deny_write_access().
+ * because FMODE_EXEC flag is not passed to f_op->open(),
+ * set it to file->private_data temporary.
+ */
+void au_store_oflag(struct nameidata *nd, struct inode *inode)
+{
+	if (nd
+	    /* && !(nd->flags & LOOKUP_CONTINUE) */
+	    && (nd->flags & LOOKUP_OPEN)
+	    && (nd->intent.open.flags & vfsub_fmode_to_uint(FMODE_EXEC))
+	    && inode
+	    && S_ISREG(inode->i_mode)) {
+		/* suppress a warning in lp64 */
+		unsigned long flags = nd->intent.open.flags;
+		nd->intent.open.file->private_data = (void *)flags;
+		/* smp_mb(); */
+	}
+}
+
+/* drop flags for writing */
+unsigned int au_file_roflags(unsigned int flags)
+{
+	flags &= ~(O_WRONLY | O_RDWR | O_APPEND | O_CREAT | O_TRUNC);
+	flags |= O_RDONLY | O_NOATIME;
+	return flags;
+}
+
+/* common functions to regular file and dir */
+struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
+		       struct file *file)
+{
+	struct file *h_file;
+	struct dentry *h_dentry;
+	struct inode *h_inode;
+	struct super_block *sb;
+	struct au_branch *br;
+	int err;
+
+	/* a race condition can happen between open and unlink/rmdir */
+	h_file = ERR_PTR(-ENOENT);
+	h_dentry = au_h_dptr(dentry, bindex);
+	if (au_test_nfsd(current) && !h_dentry)
+		goto out;
+	h_inode = h_dentry->d_inode;
+	if (au_test_nfsd(current) && !h_inode)
+		goto out;
+	if (unlikely((!d_unhashed(dentry) && d_unhashed(h_dentry))
+		     || !h_inode))
+		goto out;
+
+	sb = dentry->d_sb;
+	br = au_sbr(sb, bindex);
+	h_file = ERR_PTR(-EACCES);
+	if (file && (file->f_mode & FMODE_EXEC)
+	    && (br->br_mnt->mnt_flags & MNT_NOEXEC))
+		goto out;
+
+	/* drop flags for writing */
+	if (au_test_ro(sb, bindex, dentry->d_inode))
+		flags = au_file_roflags(flags);
+	flags &= ~O_CREAT;
+	atomic_inc(&br->br_count);
+	h_file = dentry_open(dget(h_dentry), mntget(br->br_mnt), flags,
+			     current_cred());
+	if (IS_ERR(h_file))
+		goto out_br;
+
+	if (file && (file->f_mode & FMODE_EXEC)) {
+		h_file->f_mode |= FMODE_EXEC;
+		err = deny_write_access(h_file);
+		if (unlikely(err)) {
+			fput(h_file);
+			h_file = ERR_PTR(err);
+			goto out_br;
+		}
+	}
+	fsnotify_open(h_dentry);
+	goto out; /* success */
+
+ out_br:
+	atomic_dec(&br->br_count);
+ out:
+	return h_file;
+}
+
+int au_do_open(struct file *file, int (*open)(struct file *file, int flags))
+{
+	int err;
+	struct dentry *dentry;
+	struct super_block *sb;
+
+	dentry = file->f_dentry;
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_finfo_init(file);
+	if (unlikely(err))
+		goto out;
+
+	di_read_lock_child(dentry, AuLock_IR);
+	err = open(file, file->f_flags);
+	di_read_unlock(dentry, AuLock_IR);
+
+	fi_write_unlock(file);
+	if (unlikely(err))
+		au_finfo_fin(file);
+ out:
+	si_read_unlock(sb);
+	return err;
+}
+
+int au_reopen_nondir(struct file *file)
+{
+	int err;
+	aufs_bindex_t bstart, bindex, bend;
+	struct dentry *dentry;
+	struct file *h_file, *h_file_tmp;
+
+	dentry = file->f_dentry;
+	bstart = au_dbstart(dentry);
+	h_file_tmp = NULL;
+	if (au_fbstart(file) == bstart) {
+		h_file = au_h_fptr(file, bstart);
+		if (file->f_mode == h_file->f_mode)
+			return 0; /* success */
+		h_file_tmp = h_file;
+		get_file(h_file_tmp);
+		au_set_h_fptr(file, bstart, NULL);
+	}
+	AuDebugOn(au_fbstart(file) < bstart
+		  || au_fi(file)->fi_hfile[0 + bstart].hf_file);
+
+	h_file = au_h_open(dentry, bstart, file->f_flags & ~O_TRUNC, file);
+	err = PTR_ERR(h_file);
+	if (IS_ERR(h_file))
+		goto out; /* todo: close all? */
+
+	err = 0;
+	au_set_fbstart(file, bstart);
+	au_set_h_fptr(file, bstart, h_file);
+	au_update_figen(file);
+	/* todo: necessary? */
+	/* file->f_ra = h_file->f_ra; */
+
+	/* close lower files */
+	bend = au_fbend(file);
+	for (bindex = bstart + 1; bindex <= bend; bindex++)
+		au_set_h_fptr(file, bindex, NULL);
+	au_set_fbend(file, bstart);
+
+ out:
+	if (h_file_tmp)
+		fput(h_file_tmp);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_reopen_wh(struct file *file, aufs_bindex_t btgt,
+			struct dentry *hi_wh)
+{
+	int err;
+	aufs_bindex_t bstart;
+	struct au_dinfo *dinfo;
+	struct dentry *h_dentry;
+
+	dinfo = au_di(file->f_dentry);
+	AuRwMustWriteLock(&dinfo->di_rwsem);
+
+	bstart = dinfo->di_bstart;
+	dinfo->di_bstart = btgt;
+	h_dentry = dinfo->di_hdentry[0 + btgt].hd_dentry;
+	dinfo->di_hdentry[0 + btgt].hd_dentry = hi_wh;
+	err = au_reopen_nondir(file);
+	dinfo->di_hdentry[0 + btgt].hd_dentry = h_dentry;
+	dinfo->di_bstart = bstart;
+
+	return err;
+}
+
+static int au_ready_to_write_wh(struct file *file, loff_t len,
+				aufs_bindex_t bcpup)
+{
+	int err;
+	struct inode *inode;
+	struct dentry *dentry, *hi_wh;
+	struct super_block *sb;
+
+	dentry = file->f_dentry;
+	inode = dentry->d_inode;
+	hi_wh = au_hi_wh(inode, bcpup);
+	if (!hi_wh)
+		err = au_sio_cpup_wh(dentry, bcpup, len, file);
+	else
+		/* already copied-up after unlink */
+		err = au_reopen_wh(file, bcpup, hi_wh);
+
+	sb = dentry->d_sb;
+	if (!err && inode->i_nlink > 1 && au_opt_test(au_mntflags(sb), PLINK))
+		au_plink_append(inode, bcpup, au_h_dptr(dentry, bcpup));
+
+	return err;
+}
+
+/*
+ * prepare the @file for writing.
+ */
+int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin)
+{
+	int err;
+	aufs_bindex_t bstart, bcpup;
+	struct dentry *dentry, *parent, *h_dentry;
+	struct inode *h_inode, *inode;
+	struct super_block *sb;
+
+	dentry = file->f_dentry;
+	sb = dentry->d_sb;
+	bstart = au_fbstart(file);
+	inode = dentry->d_inode;
+	err = au_test_ro(sb, bstart, inode);
+	if (!err && (au_h_fptr(file, bstart)->f_mode & FMODE_WRITE)) {
+		err = au_pin(pin, dentry, bstart, AuOpt_UDBA_NONE, /*flags*/0);
+		goto out;
+	}
+
+	/* need to cpup */
+	parent = dget_parent(dentry);
+	di_write_lock_parent(parent);
+	err = AuWbrCopyup(au_sbi(sb), dentry);
+	bcpup = err;
+	if (unlikely(err < 0))
+		goto out_dgrade;
+	err = 0;
+
+	if (!au_h_dptr(parent, bcpup)) {
+		err = au_cpup_dirs(dentry, bcpup);
+		if (unlikely(err))
+			goto out_dgrade;
+	}
+
+	err = au_pin(pin, dentry, bcpup, AuOpt_UDBA_NONE,
+		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
+	if (unlikely(err))
+		goto out_dgrade;
+
+	h_dentry = au_h_fptr(file, bstart)->f_dentry;
+	h_inode = h_dentry->d_inode;
+	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+	if (d_unhashed(dentry) /* || d_unhashed(h_dentry) */
+	    /* || !h_inode->i_nlink */) {
+		err = au_ready_to_write_wh(file, len, bcpup);
+		di_downgrade_lock(parent, AuLock_IR);
+	} else {
+		di_downgrade_lock(parent, AuLock_IR);
+		if (!au_h_dptr(dentry, bcpup))
+			err = au_sio_cpup_simple(dentry, bcpup, len,
+						 AuCpup_DTIME);
+		if (!err)
+			err = au_reopen_nondir(file);
+	}
+	mutex_unlock(&h_inode->i_mutex);
+
+	if (!err) {
+		au_pin_set_parent_lflag(pin, /*lflag*/0);
+		goto out_dput; /* success */
+	}
+	au_unpin(pin);
+	goto out_unlock;
+
+ out_dgrade:
+	di_downgrade_lock(parent, AuLock_IR);
+ out_unlock:
+	di_read_unlock(parent, AuLock_IR);
+ out_dput:
+	dput(parent);
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_file_refresh_by_inode(struct file *file, int *need_reopen)
+{
+	int err;
+	aufs_bindex_t bstart;
+	struct au_pin pin;
+	struct au_finfo *finfo;
+	struct dentry *dentry, *parent, *hi_wh;
+	struct inode *inode;
+	struct super_block *sb;
+
+	FiMustWriteLock(file);
+
+	err = 0;
+	finfo = au_fi(file);
+	dentry = file->f_dentry;
+	sb = dentry->d_sb;
+	inode = dentry->d_inode;
+	bstart = au_ibstart(inode);
+	if (bstart == finfo->fi_bstart)
+		goto out;
+
+	parent = dget_parent(dentry);
+	if (au_test_ro(sb, bstart, inode)) {
+		di_read_lock_parent(parent, !AuLock_IR);
+		err = AuWbrCopyup(au_sbi(sb), dentry);
+		bstart = err;
+		di_read_unlock(parent, !AuLock_IR);
+		if (unlikely(err < 0))
+			goto out_parent;
+		err = 0;
+	}
+
+	di_read_lock_parent(parent, AuLock_IR);
+	hi_wh = au_hi_wh(inode, bstart);
+	if (au_opt_test(au_mntflags(sb), PLINK)
+	    && au_plink_test(inode)
+	    && !d_unhashed(dentry)) {
+		err = au_test_and_cpup_dirs(dentry, bstart);
+		if (unlikely(err))
+			goto out_unlock;
+
+		/* always superio. */
+		err = au_pin(&pin, dentry, bstart, AuOpt_UDBA_NONE,
+			     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
+		if (!err)
+			err = au_sio_cpup_simple(dentry, bstart, -1,
+						 AuCpup_DTIME);
+		au_unpin(&pin);
+	} else if (hi_wh) {
+		/* already copied-up after unlink */
+		err = au_reopen_wh(file, bstart, hi_wh);
+		*need_reopen = 0;
+	}
+
+ out_unlock:
+	di_read_unlock(parent, AuLock_IR);
+ out_parent:
+	dput(parent);
+ out:
+	return err;
+}
+
+static void au_do_refresh_file(struct file *file)
+{
+	aufs_bindex_t bindex, bend, new_bindex, brid;
+	struct au_hfile *p, tmp, *q;
+	struct au_finfo *finfo;
+	struct super_block *sb;
+
+	FiMustWriteLock(file);
+
+	sb = file->f_dentry->d_sb;
+	finfo = au_fi(file);
+	p = finfo->fi_hfile + finfo->fi_bstart;
+	brid = p->hf_br->br_id;
+	bend = finfo->fi_bend;
+	for (bindex = finfo->fi_bstart; bindex <= bend; bindex++, p++) {
+		if (!p->hf_file)
+			continue;
+
+		new_bindex = au_br_index(sb, p->hf_br->br_id);
+		if (new_bindex == bindex)
+			continue;
+		if (new_bindex < 0) {
+			au_set_h_fptr(file, bindex, NULL);
+			continue;
+		}
+
+		/* swap two lower inode, and loop again */
+		q = finfo->fi_hfile + new_bindex;
+		tmp = *q;
+		*q = *p;
+		*p = tmp;
+		if (tmp.hf_file) {
+			bindex--;
+			p--;
+		}
+	}
+
+	p = finfo->fi_hfile;
+	if (!au_test_mmapped(file) && !d_unhashed(file->f_dentry)) {
+		bend = au_sbend(sb);
+		for (finfo->fi_bstart = 0; finfo->fi_bstart <= bend;
+		     finfo->fi_bstart++, p++)
+			if (p->hf_file) {
+				if (p->hf_file->f_dentry
+				    && p->hf_file->f_dentry->d_inode)
+					break;
+				else
+					au_hfput(p, file);
+			}
+	} else {
+		bend = au_br_index(sb, brid);
+		for (finfo->fi_bstart = 0; finfo->fi_bstart < bend;
+		     finfo->fi_bstart++, p++)
+			if (p->hf_file)
+				au_hfput(p, file);
+		bend = au_sbend(sb);
+	}
+
+	p = finfo->fi_hfile + bend;
+	for (finfo->fi_bend = bend; finfo->fi_bend >= finfo->fi_bstart;
+	     finfo->fi_bend--, p--)
+		if (p->hf_file) {
+			if (p->hf_file->f_dentry
+			    && p->hf_file->f_dentry->d_inode)
+				break;
+			else
+				au_hfput(p, file);
+		}
+	AuDebugOn(finfo->fi_bend < finfo->fi_bstart);
+}
+
+/*
+ * after branch manipulating, refresh the file.
+ */
+static int refresh_file(struct file *file, int (*reopen)(struct file *file))
+{
+	int err, need_reopen;
+	struct dentry *dentry;
+	aufs_bindex_t bend, bindex;
+
+	dentry = file->f_dentry;
+	err = au_fi_realloc(au_fi(file), au_sbend(dentry->d_sb) + 1);
+	if (unlikely(err))
+		goto out;
+	au_do_refresh_file(file);
+
+	err = 0;
+	need_reopen = 1;
+	if (!au_test_mmapped(file))
+		err = au_file_refresh_by_inode(file, &need_reopen);
+	if (!err && need_reopen && !d_unhashed(dentry))
+		err = reopen(file);
+	if (!err) {
+		au_update_figen(file);
+		return 0; /* success */
+	}
+
+	/* error, close all lower files */
+	bend = au_fbend(file);
+	for (bindex = au_fbstart(file); bindex <= bend; bindex++)
+		au_set_h_fptr(file, bindex, NULL);
+
+ out:
+	return err;
+}
+
+/* common function to regular file and dir */
+int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
+			  int wlock)
+{
+	int err;
+	unsigned int sigen, figen;
+	aufs_bindex_t bstart;
+	unsigned char pseudo_link;
+	struct dentry *dentry;
+
+	err = 0;
+	dentry = file->f_dentry;
+	sigen = au_sigen(dentry->d_sb);
+	fi_write_lock(file);
+	figen = au_figen(file);
+	di_write_lock_child(dentry);
+	bstart = au_dbstart(dentry);
+	pseudo_link = (bstart != au_ibstart(dentry->d_inode));
+	if (sigen == figen && !pseudo_link && au_fbstart(file) == bstart) {
+		if (!wlock) {
+			di_downgrade_lock(dentry, AuLock_IR);
+			fi_downgrade_lock(file);
+		}
+		goto out; /* success */
+	}
+
+	AuDbg("sigen %d, figen %d\n", sigen, figen);
+	if (sigen != au_digen(dentry)
+	    || sigen != au_iigen(dentry->d_inode)) {
+		err = au_reval_dpath(dentry, sigen);
+		if (unlikely(err < 0))
+			goto out;
+		AuDebugOn(au_digen(dentry) != sigen
+			  || au_iigen(dentry->d_inode) != sigen);
+	}
+
+	err = refresh_file(file, reopen);
+	if (!err) {
+		if (!wlock) {
+			di_downgrade_lock(dentry, AuLock_IR);
+			fi_downgrade_lock(file);
+		}
+	} else {
+		di_write_unlock(dentry);
+		fi_write_unlock(file);
+	}
+
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* cf. aufs_nopage() */
+/* for madvise(2) */
+static int aufs_readpage(struct file *file __maybe_unused, struct page *page)
+{
+	unlock_page(page);
+	return 0;
+}
+
+/* they will never be called. */
+#ifdef CONFIG_AUFS_DEBUG
+static int aufs_write_begin(struct file *file, struct address_space *mapping,
+			    loff_t pos, unsigned len, unsigned flags,
+			    struct page **pagep, void **fsdata)
+{ AuUnsupport(); return 0; }
+static int aufs_write_end(struct file *file, struct address_space *mapping,
+			  loff_t pos, unsigned len, unsigned copied,
+			  struct page *page, void *fsdata)
+{ AuUnsupport(); return 0; }
+static int aufs_writepage(struct page *page, struct writeback_control *wbc)
+{ AuUnsupport(); return 0; }
+static void aufs_sync_page(struct page *page)
+{ AuUnsupport(); }
+
+static int aufs_set_page_dirty(struct page *page)
+{ AuUnsupport(); return 0; }
+static void aufs_invalidatepage(struct page *page, unsigned long offset)
+{ AuUnsupport(); }
+static int aufs_releasepage(struct page *page, gfp_t gfp)
+{ AuUnsupport(); return 0; }
+static ssize_t aufs_direct_IO(int rw, struct kiocb *iocb,
+			      const struct iovec *iov, loff_t offset,
+			      unsigned long nr_segs)
+{ AuUnsupport(); return 0; }
+#endif /* CONFIG_AUFS_DEBUG */
+
+struct address_space_operations aufs_aop = {
+	.readpage	= aufs_readpage,
+#ifdef CONFIG_AUFS_DEBUG
+	.writepage	= aufs_writepage,
+	.sync_page	= aufs_sync_page,
+	.set_page_dirty	= aufs_set_page_dirty,
+	.write_begin	= aufs_write_begin,
+	.write_end	= aufs_write_end,
+	.invalidatepage	= aufs_invalidatepage,
+	.releasepage	= aufs_releasepage,
+	.direct_IO	= aufs_direct_IO,
+#endif /* CONFIG_AUFS_DEBUG */
+};
diff -Nur linux-2.6.31.4.orig/fs/aufs/file.h linux-2.6.31.4/fs/aufs/file.h
--- linux-2.6.31.4.orig/fs/aufs/file.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/file.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,175 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * file operations
+ */
+
+#ifndef __AUFS_FILE_H__
+#define __AUFS_FILE_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/aufs_type.h>
+#include "rwsem.h"
+
+struct au_branch;
+struct au_hfile {
+	struct file		*hf_file;
+	struct au_branch	*hf_br;
+};
+
+struct au_vdir;
+struct au_finfo {
+	atomic_t		fi_generation;
+
+	struct au_rwsem		fi_rwsem;
+	struct au_hfile		*fi_hfile;
+	aufs_bindex_t		fi_bstart, fi_bend;
+
+	union {
+		/* non-dir only */
+		struct {
+			struct vm_operations_struct	*fi_h_vm_ops;
+			struct vm_operations_struct	*fi_vm_ops;
+		};
+
+		/* dir only */
+		struct {
+			struct au_vdir		*fi_vdir_cache;
+			int			fi_maintain_plink;
+		};
+	};
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* file.c */
+extern struct address_space_operations aufs_aop;
+void au_store_oflag(struct nameidata *nd, struct inode *inode);
+unsigned int au_file_roflags(unsigned int flags);
+struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
+		       struct file *file);
+int au_do_open(struct file *file, int (*open)(struct file *file, int flags));
+int au_reopen_nondir(struct file *file);
+struct au_pin;
+int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin);
+int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
+			  int wlock);
+
+/* poll.c */
+#ifdef CONFIG_AUFS_POLL
+unsigned int aufs_poll(struct file *file, poll_table *wait);
+#endif
+
+/* f_op.c */
+extern const struct file_operations aufs_file_fop;
+int aufs_flush(struct file *file, fl_owner_t id);
+
+/* finfo.c */
+void au_hfput(struct au_hfile *hf, struct file *file);
+void au_set_h_fptr(struct file *file, aufs_bindex_t bindex,
+		   struct file *h_file);
+
+void au_update_figen(struct file *file);
+
+void au_finfo_fin(struct file *file);
+int au_finfo_init(struct file *file);
+int au_fi_realloc(struct au_finfo *finfo, int nbr);
+
+/* ---------------------------------------------------------------------- */
+
+static inline struct au_finfo *au_fi(struct file *file)
+{
+	return file->private_data;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * fi_read_lock, fi_write_lock,
+ * fi_read_unlock, fi_write_unlock, fi_downgrade_lock
+ */
+AuSimpleRwsemFuncs(fi, struct file *f, &au_fi(f)->fi_rwsem);
+
+#define FiMustNoWaiters(f)	AuRwMustNoWaiters(&au_fi(f)->fi_rwsem)
+#define FiMustAnyLock(f)	AuRwMustAnyLock(&au_fi(f)->fi_rwsem)
+#define FiMustWriteLock(f)	AuRwMustWriteLock(&au_fi(f)->fi_rwsem)
+
+/* ---------------------------------------------------------------------- */
+
+/* todo: hard/soft set? */
+static inline aufs_bindex_t au_fbstart(struct file *file)
+{
+	FiMustAnyLock(file);
+	return au_fi(file)->fi_bstart;
+}
+
+static inline aufs_bindex_t au_fbend(struct file *file)
+{
+	FiMustAnyLock(file);
+	return au_fi(file)->fi_bend;
+}
+
+static inline struct au_vdir *au_fvdir_cache(struct file *file)
+{
+	FiMustAnyLock(file);
+	return au_fi(file)->fi_vdir_cache;
+}
+
+static inline void au_set_fbstart(struct file *file, aufs_bindex_t bindex)
+{
+	FiMustWriteLock(file);
+	au_fi(file)->fi_bstart = bindex;
+}
+
+static inline void au_set_fbend(struct file *file, aufs_bindex_t bindex)
+{
+	FiMustWriteLock(file);
+	au_fi(file)->fi_bend = bindex;
+}
+
+static inline void au_set_fvdir_cache(struct file *file,
+				      struct au_vdir *vdir_cache)
+{
+	FiMustWriteLock(file);
+	au_fi(file)->fi_vdir_cache = vdir_cache;
+}
+
+static inline struct file *au_h_fptr(struct file *file, aufs_bindex_t bindex)
+{
+	FiMustAnyLock(file);
+	return au_fi(file)->fi_hfile[0 + bindex].hf_file;
+}
+
+/* todo: memory barrier? */
+static inline unsigned int au_figen(struct file *f)
+{
+	return atomic_read(&au_fi(f)->fi_generation);
+}
+
+static inline int au_test_mmapped(struct file *f)
+{
+	FiMustAnyLock(f);
+	return !!(au_fi(f)->fi_h_vm_ops);
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_FILE_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/finfo.c linux-2.6.31.4/fs/aufs/finfo.c
--- linux-2.6.31.4.orig/fs/aufs/finfo.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/finfo.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * file private data
+ */
+
+#include <linux/file.h>
+#include "aufs.h"
+
+void au_hfput(struct au_hfile *hf, struct file *file)
+{
+	if (file->f_mode & FMODE_EXEC)
+		allow_write_access(hf->hf_file);
+	fput(hf->hf_file);
+	hf->hf_file = NULL;
+	atomic_dec_return(&hf->hf_br->br_count);
+	hf->hf_br = NULL;
+}
+
+void au_set_h_fptr(struct file *file, aufs_bindex_t bindex, struct file *val)
+{
+	struct au_finfo *finfo = au_fi(file);
+	struct au_hfile *hf;
+
+	hf = finfo->fi_hfile + bindex;
+	if (hf->hf_file)
+		au_hfput(hf, file);
+	if (val) {
+		hf->hf_file = val;
+		hf->hf_br = au_sbr(file->f_dentry->d_sb, bindex);
+	}
+}
+
+void au_update_figen(struct file *file)
+{
+	atomic_set(&au_fi(file)->fi_generation, au_digen(file->f_dentry));
+	/* smp_mb(); */ /* atomic_set */
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_finfo_fin(struct file *file)
+{
+	struct au_finfo *finfo;
+	aufs_bindex_t bindex, bend;
+
+	fi_write_lock(file);
+	bend = au_fbend(file);
+	bindex = au_fbstart(file);
+	if (bindex >= 0)
+		/*
+		 * calls fput() instead of filp_close(),
+		 * since no dnotify or lock for the lower file.
+		 */
+		for (; bindex <= bend; bindex++)
+			au_set_h_fptr(file, bindex, NULL);
+
+	finfo = au_fi(file);
+	au_dbg_verify_hf(finfo);
+	kfree(finfo->fi_hfile);
+	fi_write_unlock(file);
+	AuRwDestroy(&finfo->fi_rwsem);
+	au_cache_free_finfo(finfo);
+}
+
+int au_finfo_init(struct file *file)
+{
+	struct au_finfo *finfo;
+	struct dentry *dentry;
+	unsigned long ul;
+
+	dentry = file->f_dentry;
+	finfo = au_cache_alloc_finfo();
+	if (unlikely(!finfo))
+		goto out;
+
+	finfo->fi_hfile = kcalloc(au_sbend(dentry->d_sb) + 1,
+				  sizeof(*finfo->fi_hfile), GFP_NOFS);
+	if (unlikely(!finfo->fi_hfile))
+		goto out_finfo;
+
+	au_rw_init_wlock(&finfo->fi_rwsem);
+	finfo->fi_bstart = -1;
+	finfo->fi_bend = -1;
+	atomic_set(&finfo->fi_generation, au_digen(dentry));
+	/* smp_mb(); */ /* atomic_set */
+
+	/* cf. au_store_oflag() */
+	/* suppress a warning in lp64 */
+	ul = (unsigned long)file->private_data;
+	file->f_mode |= (vfsub_uint_to_fmode(ul) & FMODE_EXEC);
+	file->private_data = finfo;
+	return 0; /* success */
+
+ out_finfo:
+	au_cache_free_finfo(finfo);
+ out:
+	return -ENOMEM;
+}
+
+int au_fi_realloc(struct au_finfo *finfo, int nbr)
+{
+	int err, sz;
+	struct au_hfile *hfp;
+
+	err = -ENOMEM;
+	sz = sizeof(*hfp) * (finfo->fi_bend + 1);
+	if (!sz)
+		sz = sizeof(*hfp);
+	hfp = au_kzrealloc(finfo->fi_hfile, sz, sizeof(*hfp) * nbr, GFP_NOFS);
+	if (hfp) {
+		finfo->fi_hfile = hfp;
+		err = 0;
+	}
+
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/f_op.c linux-2.6.31.4/fs/aufs/f_op.c
--- linux-2.6.31.4.orig/fs/aufs/f_op.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/f_op.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,802 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * file and vm operations
+ */
+
+#include <linux/file.h>
+#include <linux/fs_stack.h>
+#include <linux/mm.h>
+#include <linux/security.h>
+#include "aufs.h"
+
+/* common function to regular file and dir */
+int aufs_flush(struct file *file, fl_owner_t id)
+{
+	int err;
+	aufs_bindex_t bindex, bend;
+	struct dentry *dentry;
+	struct file *h_file;
+
+	dentry = file->f_dentry;
+	si_noflush_read_lock(dentry->d_sb);
+	fi_read_lock(file);
+	di_read_lock_child(dentry, AuLock_IW);
+
+	err = 0;
+	bend = au_fbend(file);
+	for (bindex = au_fbstart(file); !err && bindex <= bend; bindex++) {
+		h_file = au_h_fptr(file, bindex);
+		if (!h_file || !h_file->f_op || !h_file->f_op->flush)
+			continue;
+
+		err = h_file->f_op->flush(h_file, id);
+		if (!err)
+			vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL);
+		/*ignore*/
+	}
+	au_cpup_attr_timesizes(dentry->d_inode);
+
+	di_read_unlock(dentry, AuLock_IW);
+	fi_read_unlock(file);
+	si_read_unlock(dentry->d_sb);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int do_open_nondir(struct file *file, int flags)
+{
+	int err;
+	aufs_bindex_t bindex;
+	struct file *h_file;
+	struct dentry *dentry;
+	struct au_finfo *finfo;
+
+	FiMustWriteLock(file);
+
+	err = 0;
+	dentry = file->f_dentry;
+	finfo = au_fi(file);
+	finfo->fi_h_vm_ops = NULL;
+	finfo->fi_vm_ops = NULL;
+	bindex = au_dbstart(dentry);
+	/* O_TRUNC is processed already */
+	BUG_ON(au_test_ro(dentry->d_sb, bindex, dentry->d_inode)
+	       && (flags & O_TRUNC));
+
+	h_file = au_h_open(dentry, bindex, flags, file);
+	if (IS_ERR(h_file))
+		err = PTR_ERR(h_file);
+	else {
+		au_set_fbstart(file, bindex);
+		au_set_fbend(file, bindex);
+		au_set_h_fptr(file, bindex, h_file);
+		au_update_figen(file);
+		/* todo: necessary? */
+		/* file->f_ra = h_file->f_ra; */
+	}
+	return err;
+}
+
+static int aufs_open_nondir(struct inode *inode __maybe_unused,
+			    struct file *file)
+{
+	return au_do_open(file, do_open_nondir);
+}
+
+static int aufs_release_nondir(struct inode *inode __maybe_unused,
+			       struct file *file)
+{
+	struct super_block *sb = file->f_dentry->d_sb;
+
+	si_noflush_read_lock(sb);
+	kfree(au_fi(file)->fi_vm_ops);
+	au_finfo_fin(file);
+	si_read_unlock(sb);
+	return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static ssize_t aufs_read(struct file *file, char __user *buf, size_t count,
+			 loff_t *ppos)
+{
+	ssize_t err;
+	struct dentry *dentry;
+	struct file *h_file;
+	struct super_block *sb;
+
+	dentry = file->f_dentry;
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
+	if (unlikely(err))
+		goto out;
+
+	h_file = au_h_fptr(file, au_fbstart(file));
+	err = vfsub_read_u(h_file, buf, count, ppos);
+	/* todo: necessary? */
+	/* file->f_ra = h_file->f_ra; */
+	fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
+
+	di_read_unlock(dentry, AuLock_IR);
+	fi_read_unlock(file);
+ out:
+	si_read_unlock(sb);
+	return err;
+}
+
+static ssize_t aufs_write(struct file *file, const char __user *ubuf,
+			  size_t count, loff_t *ppos)
+{
+	ssize_t err;
+	aufs_bindex_t bstart;
+	struct au_pin pin;
+	struct dentry *dentry;
+	struct inode *inode;
+	struct super_block *sb;
+	struct file *h_file;
+	char __user *buf = (char __user *)ubuf;
+
+	dentry = file->f_dentry;
+	sb = dentry->d_sb;
+	inode = dentry->d_inode;
+	mutex_lock(&inode->i_mutex);
+	si_read_lock(sb, AuLock_FLUSH);
+
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
+	if (unlikely(err))
+		goto out;
+
+	err = au_ready_to_write(file, -1, &pin);
+	di_downgrade_lock(dentry, AuLock_IR);
+	if (unlikely(err))
+		goto out_unlock;
+
+	bstart = au_fbstart(file);
+	h_file = au_h_fptr(file, bstart);
+	au_unpin(&pin);
+	err = vfsub_write_u(h_file, buf, count, ppos);
+	au_cpup_attr_timesizes(inode);
+	inode->i_mode = h_file->f_dentry->d_inode->i_mode;
+
+ out_unlock:
+	di_read_unlock(dentry, AuLock_IR);
+	fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	mutex_unlock(&inode->i_mutex);
+	return err;
+}
+
+static ssize_t aufs_aio_read(struct kiocb *kio, const struct iovec *iov,
+			     unsigned long nv, loff_t pos)
+{
+	ssize_t err;
+	struct file *file, *h_file;
+	struct dentry *dentry;
+	struct super_block *sb;
+
+	file = kio->ki_filp;
+	dentry = file->f_dentry;
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
+	if (unlikely(err))
+		goto out;
+
+	err = -ENOSYS;
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (h_file->f_op && h_file->f_op->aio_read) {
+		err = security_file_permission(h_file, MAY_READ);
+		if (unlikely(err))
+			goto out_unlock;
+		if (!is_sync_kiocb(kio)) {
+			get_file(h_file);
+			fput(file);
+		}
+		kio->ki_filp = h_file;
+		err = h_file->f_op->aio_read(kio, iov, nv, pos);
+		/* todo: necessary? */
+		/* file->f_ra = h_file->f_ra; */
+		fsstack_copy_attr_atime(dentry->d_inode,
+					h_file->f_dentry->d_inode);
+	} else
+		/* currently there is no such fs */
+		WARN_ON_ONCE(h_file->f_op && h_file->f_op->read);
+
+ out_unlock:
+	di_read_unlock(dentry, AuLock_IR);
+	fi_read_unlock(file);
+ out:
+	si_read_unlock(sb);
+	return err;
+}
+
+static ssize_t aufs_aio_write(struct kiocb *kio, const struct iovec *iov,
+			      unsigned long nv, loff_t pos)
+{
+	ssize_t err;
+	aufs_bindex_t bstart;
+	struct au_pin pin;
+	struct dentry *dentry;
+	struct inode *inode;
+	struct super_block *sb;
+	struct file *file, *h_file;
+
+	file = kio->ki_filp;
+	dentry = file->f_dentry;
+	sb = dentry->d_sb;
+	inode = dentry->d_inode;
+	mutex_lock(&inode->i_mutex);
+	si_read_lock(sb, AuLock_FLUSH);
+
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
+	if (unlikely(err))
+		goto out;
+
+	err = au_ready_to_write(file, -1, &pin);
+	di_downgrade_lock(dentry, AuLock_IR);
+	if (unlikely(err))
+		goto out_unlock;
+
+	err = -ENOSYS;
+	bstart = au_fbstart(file);
+	h_file = au_h_fptr(file, bstart);
+	au_unpin(&pin);
+	if (h_file->f_op && h_file->f_op->aio_write) {
+		err = security_file_permission(h_file, MAY_WRITE);
+		if (unlikely(err))
+			goto out_unlock;
+		if (!is_sync_kiocb(kio)) {
+			get_file(h_file);
+			fput(file);
+		}
+		kio->ki_filp = h_file;
+		err = h_file->f_op->aio_write(kio, iov, nv, pos);
+		au_cpup_attr_timesizes(inode);
+		inode->i_mode = h_file->f_dentry->d_inode->i_mode;
+	} else
+		/* currently there is no such fs */
+		WARN_ON_ONCE(h_file->f_op && h_file->f_op->write);
+
+ out_unlock:
+	di_read_unlock(dentry, AuLock_IR);
+	fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	mutex_unlock(&inode->i_mutex);
+	return err;
+}
+
+static ssize_t aufs_splice_read(struct file *file, loff_t *ppos,
+				struct pipe_inode_info *pipe, size_t len,
+				unsigned int flags)
+{
+	ssize_t err;
+	struct file *h_file;
+	struct dentry *dentry;
+	struct super_block *sb;
+
+	dentry = file->f_dentry;
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
+	if (unlikely(err))
+		goto out;
+
+	err = -EINVAL;
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (au_test_loopback_kthread()) {
+		file->f_mapping = h_file->f_mapping;
+		smp_mb(); /* unnecessary? */
+	}
+	err = vfsub_splice_to(h_file, ppos, pipe, len, flags);
+	/* todo: necessasry? */
+	/* file->f_ra = h_file->f_ra; */
+	fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
+
+	di_read_unlock(dentry, AuLock_IR);
+	fi_read_unlock(file);
+
+ out:
+	si_read_unlock(sb);
+	return err;
+}
+
+static ssize_t
+aufs_splice_write(struct pipe_inode_info *pipe, struct file *file, loff_t *ppos,
+		  size_t len, unsigned int flags)
+{
+	ssize_t err;
+	struct au_pin pin;
+	struct dentry *dentry;
+	struct inode *inode;
+	struct super_block *sb;
+	struct file *h_file;
+
+	dentry = file->f_dentry;
+	inode = dentry->d_inode;
+	mutex_lock(&inode->i_mutex);
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
+	if (unlikely(err))
+		goto out;
+
+	err = au_ready_to_write(file, -1, &pin);
+	di_downgrade_lock(dentry, AuLock_IR);
+	if (unlikely(err))
+		goto out_unlock;
+
+	h_file = au_h_fptr(file, au_fbstart(file));
+	au_unpin(&pin);
+	err = vfsub_splice_from(pipe, h_file, ppos, len, flags);
+	au_cpup_attr_timesizes(inode);
+	inode->i_mode = h_file->f_dentry->d_inode->i_mode;
+
+ out_unlock:
+	di_read_unlock(dentry, AuLock_IR);
+	fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	mutex_unlock(&inode->i_mutex);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct file *au_safe_file(struct vm_area_struct *vma)
+{
+	struct file *file;
+
+	file = vma->vm_file;
+	if (file->private_data && au_test_aufs(file->f_dentry->d_sb))
+		return file;
+	return NULL;
+}
+
+static void au_reset_file(struct vm_area_struct *vma, struct file *file)
+{
+	vma->vm_file = file;
+	/* smp_mb(); */ /* flush vm_file */
+}
+
+static int aufs_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	int err;
+	static DECLARE_WAIT_QUEUE_HEAD(wq);
+	struct file *file, *h_file;
+	struct au_finfo *finfo;
+
+	/* todo: non-robr mode, user vm_file as it is? */
+	wait_event(wq, (file = au_safe_file(vma)));
+
+	/* do not revalidate, no si lock */
+	finfo = au_fi(file);
+	h_file = finfo->fi_hfile[0 + finfo->fi_bstart].hf_file;
+	AuDebugOn(!h_file || !finfo->fi_h_vm_ops);
+
+	fi_write_lock(file);
+	vma->vm_file = h_file;
+	err = finfo->fi_h_vm_ops->fault(vma, vmf);
+	/* todo: necessary? */
+	/* file->f_ra = h_file->f_ra; */
+	au_reset_file(vma, file);
+	fi_write_unlock(file);
+#if 0 /* def CONFIG_SMP */
+	/* wake_up_nr(&wq, online_cpu - 1); */
+	wake_up_all(&wq);
+#else
+	wake_up(&wq);
+#endif
+
+	return err;
+}
+
+static int aufs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	int err;
+	static DECLARE_WAIT_QUEUE_HEAD(wq);
+	struct file *file, *h_file;
+	struct au_finfo *finfo;
+
+	wait_event(wq, (file = au_safe_file(vma)));
+
+	finfo = au_fi(file);
+	h_file = finfo->fi_hfile[0 + finfo->fi_bstart].hf_file;
+	AuDebugOn(!h_file || !finfo->fi_h_vm_ops);
+
+	fi_write_lock(file);
+	vma->vm_file = h_file;
+	err = finfo->fi_h_vm_ops->page_mkwrite(vma, vmf);
+	au_reset_file(vma, file);
+	fi_write_unlock(file);
+	wake_up(&wq);
+
+	return err;
+}
+
+static void aufs_vm_close(struct vm_area_struct *vma)
+{
+	static DECLARE_WAIT_QUEUE_HEAD(wq);
+	struct file *file, *h_file;
+	struct au_finfo *finfo;
+
+	wait_event(wq, (file = au_safe_file(vma)));
+
+	finfo = au_fi(file);
+	h_file = finfo->fi_hfile[0 + finfo->fi_bstart].hf_file;
+	AuDebugOn(!h_file || !finfo->fi_h_vm_ops);
+
+	fi_write_lock(file);
+	vma->vm_file = h_file;
+	finfo->fi_h_vm_ops->close(vma);
+	au_reset_file(vma, file);
+	fi_write_unlock(file);
+	wake_up(&wq);
+}
+
+static struct vm_operations_struct aufs_vm_ops = {
+	/* .close and .page_mkwrite are not set by default */
+	.fault		= aufs_fault,
+};
+
+/* ---------------------------------------------------------------------- */
+
+static struct vm_operations_struct *au_vm_ops(struct file *h_file,
+					      struct vm_area_struct *vma)
+{
+	struct vm_operations_struct *vm_ops;
+	int err;
+
+	vm_ops = ERR_PTR(-ENODEV);
+	if (!h_file->f_op || !h_file->f_op->mmap)
+		goto out;
+
+	err = h_file->f_op->mmap(h_file, vma);
+	vm_ops = ERR_PTR(err);
+	if (unlikely(err))
+		goto out;
+
+	vm_ops = vma->vm_ops;
+	err = do_munmap(current->mm, vma->vm_start,
+			vma->vm_end - vma->vm_start);
+	if (unlikely(err)) {
+		AuIOErr("failed internal unmapping %.*s, %d\n",
+			AuDLNPair(h_file->f_dentry), err);
+		vm_ops = ERR_PTR(-EIO);
+	}
+
+ out:
+	return vm_ops;
+}
+
+static int au_custom_vm_ops(struct au_finfo *finfo, struct vm_area_struct *vma)
+{
+	int err;
+	struct vm_operations_struct *h_ops;
+
+	AuRwMustAnyLock(&finfo->fi_rwsem);
+
+	err = 0;
+	h_ops = finfo->fi_h_vm_ops;
+	AuDebugOn(!h_ops);
+	if ((!h_ops->page_mkwrite && !h_ops->close)
+	    || finfo->fi_vm_ops)
+		goto out;
+
+	err = -ENOMEM;
+	finfo->fi_vm_ops = kmemdup(&aufs_vm_ops, sizeof(aufs_vm_ops), GFP_NOFS);
+	if (unlikely(!finfo->fi_vm_ops))
+		goto out;
+
+	err = 0;
+	if (h_ops->page_mkwrite)
+		finfo->fi_vm_ops->page_mkwrite = aufs_page_mkwrite;
+	if (h_ops->close)
+		finfo->fi_vm_ops->close = aufs_vm_close;
+
+	vma->vm_ops = finfo->fi_vm_ops;
+
+ out:
+	return err;
+}
+
+static int aufs_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	int err;
+	unsigned char wlock, mmapped;
+	struct dentry *dentry;
+	struct super_block *sb;
+	struct file *h_file;
+	struct vm_operations_struct *vm_ops;
+
+	dentry = file->f_dentry;
+	wlock = !!(file->f_mode & FMODE_WRITE) && (vma->vm_flags & VM_SHARED);
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
+	if (unlikely(err))
+		goto out;
+
+	mmapped = !!au_test_mmapped(file);
+	if (wlock) {
+		struct au_pin pin;
+
+		err = au_ready_to_write(file, -1, &pin);
+		di_downgrade_lock(dentry, AuLock_IR);
+		if (unlikely(err))
+			goto out_unlock;
+		au_unpin(&pin);
+	} else
+		di_downgrade_lock(dentry, AuLock_IR);
+
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (!mmapped && au_test_fs_bad_mapping(h_file->f_dentry->d_sb)) {
+		/*
+		 * by this assignment, f_mapping will differs from aufs inode
+		 * i_mapping.
+		 * if someone else mixes the use of f_dentry->d_inode and
+		 * f_mapping->host, then a problem may arise.
+		 */
+		file->f_mapping = h_file->f_mapping;
+	}
+
+	vm_ops = NULL;
+	if (!mmapped) {
+		vm_ops = au_vm_ops(h_file, vma);
+		err = PTR_ERR(vm_ops);
+		if (IS_ERR(vm_ops))
+			goto out_unlock;
+	}
+
+	/*
+	 * unnecessary to handle MAP_DENYWRITE and deny_write_access()?
+	 * currently MAP_DENYWRITE from userspace is ignored, but elf loader
+	 * sets it. when FMODE_EXEC is set (by open_exec() or sys_uselib()),
+	 * both of the aufs file and the lower file is deny_write_access()-ed.
+	 * finally I hope we can skip handlling MAP_DENYWRITE here.
+	 */
+	err = generic_file_mmap(file, vma);
+	if (unlikely(err))
+		goto out_unlock;
+
+	vma->vm_ops = &aufs_vm_ops;
+	/* test again */
+	if (!au_test_mmapped(file))
+		au_fi(file)->fi_h_vm_ops = vm_ops;
+
+	err = au_custom_vm_ops(au_fi(file), vma);
+	if (unlikely(err))
+		goto out_unlock;
+
+	vfsub_file_accessed(h_file);
+	fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
+
+ out_unlock:
+	di_read_unlock(dentry, AuLock_IR);
+	fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int aufs_fsync_nondir(struct file *file, struct dentry *dentry,
+			     int datasync)
+{
+	int err;
+	struct au_pin pin;
+	struct inode *inode;
+	struct file *h_file;
+	struct super_block *sb;
+
+	inode = dentry->d_inode;
+	IMustLock(file->f_mapping->host);
+	if (inode != file->f_mapping->host) {
+		mutex_unlock(&file->f_mapping->host->i_mutex);
+		mutex_lock(&inode->i_mutex);
+	}
+	IMustLock(inode);
+
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+
+	err = 0; /* -EBADF; */ /* posix? */
+	if (unlikely(!(file->f_mode & FMODE_WRITE)))
+		goto out;
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
+	if (unlikely(err))
+		goto out;
+
+	err = au_ready_to_write(file, -1, &pin);
+	di_downgrade_lock(dentry, AuLock_IR);
+	if (unlikely(err))
+		goto out_unlock;
+	au_unpin(&pin);
+
+	err = -EINVAL;
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (h_file->f_op && h_file->f_op->fsync) {
+		struct dentry *h_d;
+		struct mutex *h_mtx;
+
+		/*
+		 * no filemap_fdatawrite() since aufs file has no its own
+		 * mapping, but dir.
+		 */
+		h_d = h_file->f_dentry;
+		h_mtx = &h_d->d_inode->i_mutex;
+		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+		err = h_file->f_op->fsync(h_file, h_d, datasync);
+		if (!err)
+			vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL);
+		/*ignore*/
+		au_cpup_attr_timesizes(inode);
+		mutex_unlock(h_mtx);
+	}
+
+ out_unlock:
+	di_read_unlock(dentry, AuLock_IR);
+	fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	if (inode != file->f_mapping->host) {
+		mutex_unlock(&inode->i_mutex);
+		mutex_lock(&file->f_mapping->host->i_mutex);
+	}
+	return err;
+}
+
+/* no one supports this operation, currently */
+#if 0
+static int aufs_aio_fsync_nondir(struct kiocb *kio, int datasync)
+{
+	int err;
+	struct au_pin pin;
+	struct dentry *dentry;
+	struct inode *inode;
+	struct file *file, *h_file;
+	struct super_block *sb;
+
+	file = kio->ki_filp;
+	dentry = file->f_dentry;
+	inode = dentry->d_inode;
+	mutex_lock(&inode->i_mutex);
+
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+
+	err = 0; /* -EBADF; */ /* posix? */
+	if (unlikely(!(file->f_mode & FMODE_WRITE)))
+		goto out;
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
+	if (unlikely(err))
+		goto out;
+
+	err = au_ready_to_write(file, -1, &pin);
+	di_downgrade_lock(dentry, AuLock_IR);
+	if (unlikely(err))
+		goto out_unlock;
+	au_unpin(&pin);
+
+	err = -ENOSYS;
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (h_file->f_op && h_file->f_op->aio_fsync) {
+		struct dentry *h_d;
+		struct mutex *h_mtx;
+
+		h_d = h_file->f_dentry;
+		h_mtx = &h_d->d_inode->i_mutex;
+		if (!is_sync_kiocb(kio)) {
+			get_file(h_file);
+			fput(file);
+		}
+		kio->ki_filp = h_file;
+		err = h_file->f_op->aio_fsync(kio, datasync);
+		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+		if (!err)
+			vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL);
+		/*ignore*/
+		au_cpup_attr_timesizes(inode);
+		mutex_unlock(h_mtx);
+	}
+
+ out_unlock:
+	di_read_unlock(dentry, AuLock_IR);
+	fi_write_unlock(file);
+ out:
+	si_read_unlock(sb);
+	mutex_unlock(&inode->i_mutex);
+	return err;
+}
+#endif
+
+static int aufs_fasync(int fd, struct file *file, int flag)
+{
+	int err;
+	struct file *h_file;
+	struct dentry *dentry;
+	struct super_block *sb;
+
+	dentry = file->f_dentry;
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
+	if (unlikely(err))
+		goto out;
+
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (h_file->f_op && h_file->f_op->fasync)
+		err = h_file->f_op->fasync(fd, h_file, flag);
+
+	di_read_unlock(dentry, AuLock_IR);
+	fi_read_unlock(file);
+
+ out:
+	si_read_unlock(sb);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* no one supports this operation, currently */
+#if 0
+static ssize_t aufs_sendpage(struct file *file, struct page *page, int offset,
+			     size_t len, loff_t *pos , int more)
+{
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+const struct file_operations aufs_file_fop = {
+	/*
+	 * while generic_file_llseek/_unlocked() don't use BKL,
+	 * don't use it since it operates file->f_mapping->host.
+	 * in aufs, it may be a real file and may confuse users by UDBA.
+	 */
+	/* .llseek		= generic_file_llseek, */
+
+	.read		= aufs_read,
+	.write		= aufs_write,
+	.aio_read	= aufs_aio_read,
+	.aio_write	= aufs_aio_write,
+#ifdef CONFIG_AUFS_POLL
+	.poll		= aufs_poll,
+#endif
+	.mmap		= aufs_mmap,
+	.open		= aufs_open_nondir,
+	.flush		= aufs_flush,
+	.release	= aufs_release_nondir,
+	.fsync		= aufs_fsync_nondir,
+	/* .aio_fsync	= aufs_aio_fsync_nondir, */
+	.fasync		= aufs_fasync,
+	/* .sendpage	= aufs_sendpage, */
+	.splice_write	= aufs_splice_write,
+	.splice_read	= aufs_splice_read,
+#if 0
+	.aio_splice_write = aufs_aio_splice_write,
+	.aio_splice_read  = aufs_aio_splice_read
+#endif
+};
diff -Nur linux-2.6.31.4.orig/fs/aufs/fstype.h linux-2.6.31.4/fs/aufs/fstype.h
--- linux-2.6.31.4.orig/fs/aufs/fstype.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/fstype.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,474 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * judging filesystem type
+ */
+
+#ifndef __AUFS_FSTYPE_H__
+#define __AUFS_FSTYPE_H__
+
+#ifdef __KERNEL__
+
+#include <linux/cramfs_fs.h>
+#include <linux/fs.h>
+#include <linux/magic.h>
+#include <linux/romfs_fs.h>
+#include <linux/aufs_type.h>
+
+static inline int au_test_aufs(struct super_block *sb)
+{
+	return sb->s_magic == AUFS_SUPER_MAGIC;
+}
+
+static inline const char *au_sbtype(struct super_block *sb)
+{
+	return sb->s_type->name;
+}
+
+static inline int au_test_iso9660(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_ROMFS_FS) || defined(CONFIG_ROMFS_FS_MODULE)
+	return sb->s_magic == ROMFS_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_romfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_ISO9660_FS) || defined(CONFIG_ISO9660_FS_MODULE)
+	return sb->s_magic == ISOFS_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_cramfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_CRAMFS) || defined(CONFIG_CRAMFS_MODULE)
+	return sb->s_magic == CRAMFS_MAGIC;
+#endif
+	return 0;
+}
+
+static inline int au_test_nfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_NFS_FS) || defined(CONFIG_NFS_FS_MODULE)
+	return sb->s_magic == NFS_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_fuse(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_FUSE_FS) || defined(CONFIG_FUSE_FS_MODULE)
+	return sb->s_magic == FUSE_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_xfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_XFS_FS) || defined(CONFIG_XFS_FS_MODULE)
+	return sb->s_magic == XFS_SB_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_tmpfs(struct super_block *sb __maybe_unused)
+{
+#ifdef CONFIG_TMPFS
+	return sb->s_magic == TMPFS_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_ecryptfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_ECRYPT_FS) || defined(CONFIG_ECRYPT_FS_MODULE)
+	return !strcmp(au_sbtype(sb), "ecryptfs");
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_smbfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_SMB_FS) || defined(CONFIG_SMB_FS_MODULE)
+	return sb->s_magic == SMB_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_ocfs2(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_OCFS2_FS) || defined(CONFIG_OCFS2_FS_MODULE)
+	return sb->s_magic == OCFS2_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_ocfs2_dlmfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_OCFS2_FS_O2CB) || defined(CONFIG_OCFS2_FS_O2CB_MODULE)
+	return sb->s_magic == DLMFS_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_coda(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_CODA_FS) || defined(CONFIG_CODA_FS_MODULE)
+	return sb->s_magic == CODA_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_v9fs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_9P_FS) || defined(CONFIG_9P_FS_MODULE)
+	return sb->s_magic == V9FS_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_ext4(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_EXT4DEV_FS) || defined(CONFIG_EXT4DEV_FS_MODULE)
+	return sb->s_magic == EXT4_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_sysv(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_SYSV_FS) || defined(CONFIG_SYSV_FS_MODULE)
+	return !strcmp(au_sbtype(sb), "sysv");
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_ramfs(struct super_block *sb)
+{
+	return sb->s_magic == RAMFS_MAGIC;
+}
+
+static inline int au_test_ubifs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_UBIFS_FS) || defined(CONFIG_UBIFS_FS_MODULE)
+	return sb->s_magic == UBIFS_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_procfs(struct super_block *sb __maybe_unused)
+{
+#ifdef CONFIG_PROC_FS
+	return sb->s_magic == PROC_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_sysfs(struct super_block *sb __maybe_unused)
+{
+#ifdef CONFIG_SYSFS
+	return sb->s_magic == SYSFS_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_configfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_CONFIGFS_FS) || defined(CONFIG_CONFIGFS_FS_MODULE)
+	return sb->s_magic == CONFIGFS_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_minix(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_MINIX_FS) || defined(CONFIG_MINIX_FS_MODULE)
+	return sb->s_magic == MINIX3_SUPER_MAGIC
+		|| sb->s_magic == MINIX2_SUPER_MAGIC
+		|| sb->s_magic == MINIX2_SUPER_MAGIC2
+		|| sb->s_magic == MINIX_SUPER_MAGIC
+		|| sb->s_magic == MINIX_SUPER_MAGIC2;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_cifs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_CIFS_FS) || defined(CONFIGCIFS_FS_MODULE)
+	return sb->s_magic == CIFS_MAGIC_NUMBER;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_fat(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_FAT_FS) || defined(CONFIG_FAT_FS_MODULE)
+	return sb->s_magic == MSDOS_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_msdos(struct super_block *sb)
+{
+	return au_test_fat(sb);
+}
+
+static inline int au_test_vfat(struct super_block *sb)
+{
+	return au_test_fat(sb);
+}
+
+static inline int au_test_securityfs(struct super_block *sb __maybe_unused)
+{
+#ifdef CONFIG_SECURITYFS
+	return sb->s_magic == SECURITYFS_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_squashfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_SQUASHFS) || defined(CONFIG_SQUASHFS_MODULE)
+	return sb->s_magic == SQUASHFS_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_btrfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_BTRFS_FS) || defined(CONFIG_BTRFS_FS_MODULE)
+	return sb->s_magic == BTRFS_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_xenfs(struct super_block *sb __maybe_unused)
+{
+#if defined(CONFIG_XENFS) || defined(CONFIG_XENFS_MODULE)
+	return sb->s_magic == XENFS_SUPER_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+static inline int au_test_debugfs(struct super_block *sb __maybe_unused)
+{
+#ifdef CONFIG_DEBUG_FS
+	return sb->s_magic == DEBUGFS_MAGIC;
+#else
+	return 0;
+#endif
+}
+
+/* ---------------------------------------------------------------------- */
+/*
+ * they can't be an aufs branch.
+ */
+static inline int au_test_fs_unsuppoted(struct super_block *sb)
+{
+	return
+#ifndef CONFIG_AUFS_BR_RAMFS
+		au_test_ramfs(sb) ||
+#endif
+		au_test_procfs(sb)
+		|| au_test_sysfs(sb)
+		|| au_test_configfs(sb)
+		|| au_test_debugfs(sb)
+		|| au_test_securityfs(sb)
+		|| au_test_xenfs(sb)
+		/* || !strcmp(au_sbtype(sb), "unionfs") */
+		|| au_test_aufs(sb); /* will be supported in next version */
+}
+
+/*
+ * If the filesystem supports NFS-export, then it has to support NULL as
+ * a nameidata parameter for ->create(), ->lookup() and ->d_revalidate().
+ * We can apply this principle when we handle a lower filesystem.
+ */
+static inline int au_test_fs_null_nd(struct super_block *sb)
+{
+	return !!sb->s_export_op;
+}
+
+static inline int au_test_fs_remote(struct super_block *sb)
+{
+	return !au_test_tmpfs(sb)
+#ifdef CONFIG_AUFS_BR_RAMFS
+		&& !au_test_ramfs(sb)
+#endif
+		&& !(sb->s_type->fs_flags & FS_REQUIRES_DEV);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * Note: these functions (below) are created after reading ->getattr() in all
+ * filesystems under linux/fs. it means we have to do so in every update...
+ */
+
+/*
+ * some filesystems require getattr to refresh the inode attributes before
+ * referencing.
+ * in most cases, we can rely on the inode attribute in NFS (or every remote fs)
+ * and leave the work for d_revalidate()
+ */
+static inline int au_test_fs_refresh_iattr(struct super_block *sb)
+{
+	return au_test_nfs(sb)
+		|| au_test_fuse(sb)
+		/* || au_test_smbfs(sb) */	/* untested */
+		/* || au_test_ocfs2(sb) */	/* untested */
+		/* || au_test_btrfs(sb) */	/* untested */
+		/* || au_test_coda(sb) */	/* untested */
+		/* || au_test_v9fs(sb) */	/* untested */
+		;
+}
+
+/*
+ * filesystems which don't maintain i_size or i_blocks.
+ */
+static inline int au_test_fs_bad_iattr_size(struct super_block *sb)
+{
+	return au_test_xfs(sb)
+		/* || au_test_ext4(sb) */	/* untested */
+		/* || au_test_ocfs2(sb) */	/* untested */
+		/* || au_test_ocfs2_dlmfs(sb) */ /* untested */
+		/* || au_test_sysv(sb) */	/* untested */
+		/* || au_test_ubifs(sb) */	/* untested */
+		/* || au_test_minix(sb) */	/* untested */
+		;
+}
+
+/*
+ * filesystems which don't store the correct value in some of their inode
+ * attributes.
+ */
+static inline int au_test_fs_bad_iattr(struct super_block *sb)
+{
+	return au_test_fs_bad_iattr_size(sb)
+		/* || au_test_cifs(sb) */	/* untested */
+		|| au_test_fat(sb)
+		|| au_test_msdos(sb)
+		|| au_test_vfat(sb);
+}
+
+/* they don't check i_nlink in link(2) */
+static inline int au_test_fs_no_limit_nlink(struct super_block *sb)
+{
+	return au_test_tmpfs(sb)
+#ifdef CONFIG_AUFS_BR_RAMFS
+		|| au_test_ramfs(sb)
+#endif
+		|| au_test_ubifs(sb);
+}
+
+/*
+ * filesystems which sets S_NOATIME and S_NOCMTIME.
+ */
+static inline int au_test_fs_notime(struct super_block *sb)
+{
+	return au_test_nfs(sb)
+		|| au_test_fuse(sb)
+		|| au_test_ubifs(sb)
+		/* || au_test_cifs(sb) */	/* untested */
+		;
+}
+
+/*
+ * filesystems which requires replacing i_mapping.
+ */
+static inline int au_test_fs_bad_mapping(struct super_block *sb)
+{
+	return au_test_fuse(sb)
+		|| au_test_ubifs(sb);
+}
+
+/* temporary support for i#1 in cramfs */
+static inline int au_test_fs_unique_ino(struct inode *inode)
+{
+	if (au_test_cramfs(inode->i_sb))
+		return inode->i_ino != 1;
+	return 1;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * the filesystem where the xino files placed must support i/o after unlink and
+ * maintain i_size and i_blocks.
+ */
+static inline int au_test_fs_bad_xino(struct super_block *sb)
+{
+	return au_test_fs_remote(sb)
+		|| au_test_fs_bad_iattr_size(sb)
+#ifdef CONFIG_AUFS_BR_RAMFS
+		|| !(au_test_ramfs(sb) || au_test_fs_null_nd(sb))
+#else
+		|| !au_test_fs_null_nd(sb) /* to keep xino code simple */
+#endif
+		/* don't want unnecessary work for xino */
+		|| au_test_aufs(sb)
+		|| au_test_ecryptfs(sb);
+}
+
+static inline int au_test_fs_trunc_xino(struct super_block *sb)
+{
+	return au_test_tmpfs(sb)
+		|| au_test_ramfs(sb);
+}
+
+/*
+ * test if the @sb is real-readonly.
+ */
+static inline int au_test_fs_rr(struct super_block *sb)
+{
+	return au_test_squashfs(sb)
+		|| au_test_iso9660(sb)
+		|| au_test_cramfs(sb)
+		|| au_test_romfs(sb);
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_FSTYPE_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/hinotify.c linux-2.6.31.4/fs/aufs/hinotify.c
--- linux-2.6.31.4.orig/fs/aufs/hinotify.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/hinotify.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,755 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inotify for the lower directories
+ */
+
+#include "aufs.h"
+
+static const __u32 AuHinMask = (IN_MOVE | IN_DELETE | IN_CREATE);
+static struct inotify_handle *au_hin_handle;
+
+AuCacheFuncs(hinotify, HINOTIFY);
+
+int au_hin_alloc(struct au_hinode *hinode, struct inode *inode,
+		 struct inode *h_inode)
+{
+	int err;
+	struct au_hinotify *hin;
+	s32 wd;
+
+	err = -ENOMEM;
+	hin = au_cache_alloc_hinotify();
+	if (hin) {
+		AuDebugOn(hinode->hi_notify);
+		hinode->hi_notify = hin;
+		hin->hin_aufs_inode = inode;
+
+		inotify_init_watch(&hin->hin_watch);
+		wd = inotify_add_watch(au_hin_handle, &hin->hin_watch, h_inode,
+				       AuHinMask);
+		if (wd >= 0)
+			return 0; /* success */
+
+		err = wd;
+		put_inotify_watch(&hin->hin_watch);
+		au_cache_free_hinotify(hin);
+		hinode->hi_notify = NULL;
+	}
+
+	return err;
+}
+
+void au_hin_free(struct au_hinode *hinode)
+{
+	int err;
+	struct au_hinotify *hin;
+
+	hin = hinode->hi_notify;
+	if (hin) {
+		err = 0;
+		if (atomic_read(&hin->hin_watch.count))
+			err = inotify_rm_watch(au_hin_handle, &hin->hin_watch);
+		if (unlikely(err))
+			/* it means the watch is already removed */
+			AuWarn("failed inotify_rm_watch() %d\n", err);
+		au_cache_free_hinotify(hin);
+		hinode->hi_notify = NULL;
+	}
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_hin_ctl(struct au_hinode *hinode, int do_set)
+{
+	struct inode *h_inode;
+	struct inotify_watch *watch;
+
+	if (!hinode->hi_notify)
+		return;
+
+	h_inode = hinode->hi_inode;
+	IMustLock(h_inode);
+
+	/* todo: try inotify_find_update_watch()? */
+	watch = &hinode->hi_notify->hin_watch;
+	mutex_lock(&h_inode->inotify_mutex);
+	/* mutex_lock(&watch->ih->mutex); */
+	if (do_set) {
+		AuDebugOn(watch->mask & AuHinMask);
+		watch->mask |= AuHinMask;
+	} else {
+		AuDebugOn(!(watch->mask & AuHinMask));
+		watch->mask &= ~AuHinMask;
+	}
+	/* mutex_unlock(&watch->ih->mutex); */
+	mutex_unlock(&h_inode->inotify_mutex);
+}
+
+void au_reset_hinotify(struct inode *inode, unsigned int flags)
+{
+	aufs_bindex_t bindex, bend;
+	struct inode *hi;
+	struct dentry *iwhdentry;
+
+	bend = au_ibend(inode);
+	for (bindex = au_ibstart(inode); bindex <= bend; bindex++) {
+		hi = au_h_iptr(inode, bindex);
+		if (!hi)
+			continue;
+
+		/* mutex_lock_nested(&hi->i_mutex, AuLsc_I_CHILD); */
+		iwhdentry = au_hi_wh(inode, bindex);
+		if (iwhdentry)
+			dget(iwhdentry);
+		au_igrab(hi);
+		au_set_h_iptr(inode, bindex, NULL, 0);
+		au_set_h_iptr(inode, bindex, au_igrab(hi),
+			      flags & ~AuHi_XINO);
+		iput(hi);
+		dput(iwhdentry);
+		/* mutex_unlock(&hi->i_mutex); */
+	}
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int hin_xino(struct inode *inode, struct inode *h_inode)
+{
+	int err;
+	aufs_bindex_t bindex, bend, bfound, bstart;
+	struct inode *h_i;
+
+	err = 0;
+	if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
+		AuWarn("branch root dir was changed\n");
+		goto out;
+	}
+
+	bfound = -1;
+	bend = au_ibend(inode);
+	bstart = au_ibstart(inode);
+#if 0 /* reserved for future use */
+	if (bindex == bend) {
+		/* keep this ino in rename case */
+		goto out;
+	}
+#endif
+	for (bindex = bstart; bindex <= bend; bindex++) {
+		if (au_h_iptr(inode, bindex) == h_inode) {
+			bfound = bindex;
+			break;
+		}
+	}
+	if (bfound < 0)
+		goto out;
+
+	for (bindex = bstart; bindex <= bend; bindex++) {
+		h_i = au_h_iptr(inode, bindex);
+		if (!h_i)
+			continue;
+
+		err = au_xino_write(inode->i_sb, bindex, h_i->i_ino, /*ino*/0);
+		/* ignore this error */
+		/* bad action? */
+	}
+
+	/* children inode number will be broken */
+
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+static int hin_gen_tree(struct dentry *dentry)
+{
+	int err, i, j, ndentry;
+	struct au_dcsub_pages dpages;
+	struct au_dpage *dpage;
+	struct dentry **dentries;
+
+	err = au_dpages_init(&dpages, GFP_NOFS);
+	if (unlikely(err))
+		goto out;
+	err = au_dcsub_pages(&dpages, dentry, NULL, NULL);
+	if (unlikely(err))
+		goto out_dpages;
+
+	for (i = 0; i < dpages.ndpage; i++) {
+		dpage = dpages.dpages + i;
+		dentries = dpage->dentries;
+		ndentry = dpage->ndentry;
+		for (j = 0; j < ndentry; j++) {
+			struct dentry *d;
+
+			d = dentries[j];
+			if (IS_ROOT(d))
+				continue;
+
+			d_drop(d);
+			au_digen_dec(d);
+			if (d->d_inode)
+				/* todo: reset children xino?
+				   cached children only? */
+				au_iigen_dec(d->d_inode);
+		}
+	}
+
+ out_dpages:
+	au_dpages_free(&dpages);
+
+	/* discard children */
+	dentry_unhash(dentry);
+	dput(dentry);
+ out:
+	return err;
+}
+
+/*
+ * return 0 if processed.
+ */
+static int hin_gen_by_inode(char *name, unsigned int nlen, struct inode *inode,
+			    const unsigned int isdir)
+{
+	int err;
+	struct dentry *d;
+	struct qstr *dname;
+
+	err = 1;
+	if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
+		AuWarn("branch root dir was changed\n");
+		err = 0;
+		goto out;
+	}
+
+	if (!isdir) {
+		AuDebugOn(!name);
+		au_iigen_dec(inode);
+		spin_lock(&dcache_lock);
+		list_for_each_entry(d, &inode->i_dentry, d_alias) {
+			dname = &d->d_name;
+			if (dname->len != nlen
+			    && memcmp(dname->name, name, nlen))
+				continue;
+			err = 0;
+			spin_lock(&d->d_lock);
+			__d_drop(d);
+			au_digen_dec(d);
+			spin_unlock(&d->d_lock);
+			break;
+		}
+		spin_unlock(&dcache_lock);
+	} else {
+		au_fset_si(au_sbi(inode->i_sb), FAILED_REFRESH_DIRS);
+		d = d_find_alias(inode);
+		if (!d) {
+			au_iigen_dec(inode);
+			goto out;
+		}
+
+		dname = &d->d_name;
+		if (dname->len == nlen && !memcmp(dname->name, name, nlen))
+			err = hin_gen_tree(d);
+		dput(d);
+	}
+
+ out:
+	AuTraceErr(err);
+	return err;
+}
+
+static int hin_gen_by_name(struct dentry *dentry, const unsigned int isdir)
+{
+	int err;
+	struct inode *inode;
+
+	inode = dentry->d_inode;
+	if (IS_ROOT(dentry)
+	    /* || (inode && inode->i_ino == AUFS_ROOT_INO) */
+		) {
+		AuWarn("branch root dir was changed\n");
+		return 0;
+	}
+
+	err = 0;
+	if (!isdir) {
+		d_drop(dentry);
+		au_digen_dec(dentry);
+		if (inode)
+			au_iigen_dec(inode);
+	} else {
+		au_fset_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIRS);
+		if (inode)
+			err = hin_gen_tree(dentry);
+	}
+
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* hinotify job flags */
+#define AuHinJob_XINO0		1
+#define AuHinJob_GEN		(1 << 1)
+#define AuHinJob_DIRENT		(1 << 2)
+#define AuHinJob_ISDIR		(1 << 3)
+#define AuHinJob_TRYXINO0	(1 << 4)
+#define AuHinJob_MNTPNT		(1 << 5)
+#define au_ftest_hinjob(flags, name)	((flags) & AuHinJob_##name)
+#define au_fset_hinjob(flags, name)	{ (flags) |= AuHinJob_##name; }
+#define au_fclr_hinjob(flags, name)	{ (flags) &= ~AuHinJob_##name; }
+
+struct hin_job_args {
+	unsigned int flags;
+	struct inode *inode, *h_inode, *dir, *h_dir;
+	struct dentry *dentry;
+	char *h_name;
+	int h_nlen;
+};
+
+static int hin_job(struct hin_job_args *a)
+{
+	const unsigned int isdir = au_ftest_hinjob(a->flags, ISDIR);
+
+	/* reset xino */
+	if (au_ftest_hinjob(a->flags, XINO0) && a->inode)
+		hin_xino(a->inode, a->h_inode); /* ignore this error */
+
+	if (au_ftest_hinjob(a->flags, TRYXINO0)
+	    && a->inode
+	    && a->h_inode) {
+		mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
+		if (!a->h_inode->i_nlink)
+			hin_xino(a->inode, a->h_inode); /* ignore this error */
+		mutex_unlock(&a->h_inode->i_mutex);
+	}
+
+	/* make the generation obsolete */
+	if (au_ftest_hinjob(a->flags, GEN)) {
+		int err = -1;
+		if (a->inode)
+			err = hin_gen_by_inode(a->h_name, a->h_nlen, a->inode,
+					       isdir);
+		if (err && a->dentry)
+			hin_gen_by_name(a->dentry, isdir);
+		/* ignore this error */
+	}
+
+	/* make dir entries obsolete */
+	if (au_ftest_hinjob(a->flags, DIRENT) && a->inode) {
+		struct au_vdir *vdir;
+
+		vdir = au_ivdir(a->inode);
+		if (vdir)
+			vdir->vd_jiffy = 0;
+		/* IMustLock(a->inode); */
+		/* a->inode->i_version++; */
+	}
+
+	/* can do nothing but warn */
+	if (au_ftest_hinjob(a->flags, MNTPNT)
+	    && a->dentry
+	    && d_mountpoint(a->dentry))
+		AuWarn("mount-point %.*s is removed or renamed\n",
+		       AuDLNPair(a->dentry));
+
+	return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static char *in_name(u32 mask)
+{
+#ifdef CONFIG_AUFS_DEBUG
+#define test_ret(flag)	if (mask & flag) \
+				return #flag;
+	test_ret(IN_ACCESS);
+	test_ret(IN_MODIFY);
+	test_ret(IN_ATTRIB);
+	test_ret(IN_CLOSE_WRITE);
+	test_ret(IN_CLOSE_NOWRITE);
+	test_ret(IN_OPEN);
+	test_ret(IN_MOVED_FROM);
+	test_ret(IN_MOVED_TO);
+	test_ret(IN_CREATE);
+	test_ret(IN_DELETE);
+	test_ret(IN_DELETE_SELF);
+	test_ret(IN_MOVE_SELF);
+	test_ret(IN_UNMOUNT);
+	test_ret(IN_Q_OVERFLOW);
+	test_ret(IN_IGNORED);
+	return "";
+#undef test_ret
+#else
+	return "??";
+#endif
+}
+
+static struct dentry *lookup_wlock_by_name(char *name, unsigned int nlen,
+					   struct inode *dir)
+{
+	struct dentry *dentry, *d, *parent;
+	struct qstr *dname;
+
+	parent = d_find_alias(dir);
+	if (!parent)
+		return NULL;
+
+	dentry = NULL;
+	spin_lock(&dcache_lock);
+	list_for_each_entry(d, &parent->d_subdirs, d_u.d_child) {
+		/* AuDbg("%.*s\n", AuDLNPair(d)); */
+		dname = &d->d_name;
+		if (dname->len != nlen || memcmp(dname->name, name, nlen))
+			continue;
+		if (!atomic_read(&d->d_count) || !d->d_fsdata) {
+			spin_lock(&d->d_lock);
+			__d_drop(d);
+			spin_unlock(&d->d_lock);
+			continue;
+		}
+
+		dentry = dget(d);
+		break;
+	}
+	spin_unlock(&dcache_lock);
+	dput(parent);
+
+	if (dentry)
+		di_write_lock_child(dentry);
+
+	return dentry;
+}
+
+static struct inode *lookup_wlock_by_ino(struct super_block *sb,
+					 aufs_bindex_t bindex, ino_t h_ino)
+{
+	struct inode *inode;
+	ino_t ino;
+	int err;
+
+	inode = NULL;
+	err = au_xino_read(sb, bindex, h_ino, &ino);
+	if (!err && ino)
+		inode = ilookup(sb, ino);
+	if (!inode)
+		goto out;
+
+	if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
+		AuWarn("wrong root branch\n");
+		iput(inode);
+		inode = NULL;
+		goto out;
+	}
+
+	ii_write_lock_child(inode);
+
+ out:
+	return inode;
+}
+
+enum { CHILD, PARENT };
+struct postproc_args {
+	struct inode *h_dir, *dir, *h_child_inode;
+	u32 mask;
+	unsigned int flags[2];
+	unsigned int h_child_nlen;
+	char h_child_name[];
+};
+
+static void postproc(void *_args)
+{
+	struct postproc_args *a = _args;
+	struct super_block *sb;
+	aufs_bindex_t bindex, bend, bfound;
+	unsigned char xino, try_iput;
+	int err;
+	struct inode *inode;
+	ino_t h_ino;
+	struct hin_job_args args;
+	struct dentry *dentry;
+	struct au_sbinfo *sbinfo;
+
+	AuDebugOn(!_args);
+	AuDebugOn(!a->h_dir);
+	AuDebugOn(!a->dir);
+	AuDebugOn(!a->mask);
+	AuDbg("mask 0x%x %s, i%lu, hi%lu, hci%lu\n",
+	      a->mask, in_name(a->mask), a->dir->i_ino, a->h_dir->i_ino,
+	      a->h_child_inode ? a->h_child_inode->i_ino : 0);
+
+	inode = NULL;
+	dentry = NULL;
+	/*
+	 * do not lock a->dir->i_mutex here
+	 * because of d_revalidate() may cause a deadlock.
+	 */
+	sb = a->dir->i_sb;
+	AuDebugOn(!sb);
+	sbinfo = au_sbi(sb);
+	AuDebugOn(!sbinfo);
+	/* big aufs lock */
+	si_noflush_write_lock(sb);
+
+	ii_read_lock_parent(a->dir);
+	bfound = -1;
+	bend = au_ibend(a->dir);
+	for (bindex = au_ibstart(a->dir); bindex <= bend; bindex++)
+		if (au_h_iptr(a->dir, bindex) == a->h_dir) {
+			bfound = bindex;
+			break;
+		}
+	ii_read_unlock(a->dir);
+	if (unlikely(bfound < 0))
+		goto out;
+
+	xino = !!au_opt_test(au_mntflags(sb), XINO);
+	h_ino = 0;
+	if (a->h_child_inode)
+		h_ino = a->h_child_inode->i_ino;
+
+	if (a->h_child_nlen
+	    && (au_ftest_hinjob(a->flags[CHILD], GEN)
+		|| au_ftest_hinjob(a->flags[CHILD], MNTPNT)))
+		dentry = lookup_wlock_by_name(a->h_child_name, a->h_child_nlen,
+					      a->dir);
+	try_iput = 0;
+	if (dentry)
+		inode = dentry->d_inode;
+	if (xino && !inode && h_ino
+	    && (au_ftest_hinjob(a->flags[CHILD], XINO0)
+		|| au_ftest_hinjob(a->flags[CHILD], TRYXINO0)
+		|| au_ftest_hinjob(a->flags[CHILD], GEN))) {
+		inode = lookup_wlock_by_ino(sb, bfound, h_ino);
+		try_iput = 1;
+	    }
+
+	args.flags = a->flags[CHILD];
+	args.dentry = dentry;
+	args.inode = inode;
+	args.h_inode = a->h_child_inode;
+	args.dir = a->dir;
+	args.h_dir = a->h_dir;
+	args.h_name = a->h_child_name;
+	args.h_nlen = a->h_child_nlen;
+	err = hin_job(&args);
+	if (dentry) {
+		if (dentry->d_fsdata)
+			di_write_unlock(dentry);
+		dput(dentry);
+	}
+	if (inode && try_iput) {
+		ii_write_unlock(inode);
+		iput(inode);
+	}
+
+	ii_write_lock_parent(a->dir);
+	args.flags = a->flags[PARENT];
+	args.dentry = NULL;
+	args.inode = a->dir;
+	args.h_inode = a->h_dir;
+	args.dir = NULL;
+	args.h_dir = NULL;
+	args.h_name = NULL;
+	args.h_nlen = 0;
+	err = hin_job(&args);
+	ii_write_unlock(a->dir);
+
+ out:
+	au_nwt_done(&sbinfo->si_nowait);
+	si_write_unlock(sb);
+
+	iput(a->h_child_inode);
+	iput(a->h_dir);
+	iput(a->dir);
+	kfree(a);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void aufs_inotify(struct inotify_watch *watch, u32 wd __maybe_unused,
+			 u32 mask, u32 cookie __maybe_unused,
+			 const char *h_child_name, struct inode *h_child_inode)
+{
+	struct au_hinotify *hinotify;
+	struct postproc_args *args;
+	int len, wkq_err;
+	unsigned char isdir, isroot, wh;
+	char *p;
+	struct inode *dir;
+	unsigned int flags[2];
+
+	/* if IN_UNMOUNT happens, there must be another bug */
+	AuDebugOn(mask & IN_UNMOUNT);
+	if (mask & (IN_IGNORED | IN_UNMOUNT)) {
+		put_inotify_watch(watch);
+		return;
+	}
+#ifdef AuDbgHinotify
+	au_debug(1);
+	if (1 || !h_child_name || strcmp(h_child_name, AUFS_XINO_FNAME)) {
+		AuDbg("i%lu, wd %d, mask 0x%x %s, cookie 0x%x, hcname %s,"
+		      " hi%lu\n",
+		      watch->inode->i_ino, wd, mask, in_name(mask), cookie,
+		      h_child_name ? h_child_name : "",
+		      h_child_inode ? h_child_inode->i_ino : 0);
+		WARN_ON(1);
+	}
+	au_debug(0);
+#endif
+
+	hinotify = container_of(watch, struct au_hinotify, hin_watch);
+	AuDebugOn(!hinotify || !hinotify->hin_aufs_inode);
+	dir = igrab(hinotify->hin_aufs_inode);
+	if (!dir)
+		return;
+
+	isroot = (dir->i_ino == AUFS_ROOT_INO);
+	len = 0;
+	wh = 0;
+	if (h_child_name) {
+		len = strlen(h_child_name);
+		if (!memcmp(h_child_name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
+			h_child_name += AUFS_WH_PFX_LEN;
+			len -= AUFS_WH_PFX_LEN;
+			wh = 1;
+		}
+	}
+
+	isdir = 0;
+	if (h_child_inode)
+		isdir = !!S_ISDIR(h_child_inode->i_mode);
+	flags[PARENT] = AuHinJob_ISDIR;
+	flags[CHILD] = 0;
+	if (isdir)
+		flags[CHILD] = AuHinJob_ISDIR;
+	switch (mask & IN_ALL_EVENTS) {
+	case IN_MOVED_FROM:
+	case IN_MOVED_TO:
+		AuDebugOn(!h_child_name || !h_child_inode);
+		au_fset_hinjob(flags[CHILD], GEN);
+		au_fset_hinjob(flags[CHILD], XINO0);
+		au_fset_hinjob(flags[CHILD], MNTPNT);
+		au_fset_hinjob(flags[PARENT], DIRENT);
+		break;
+
+	case IN_CREATE:
+		AuDebugOn(!h_child_name || !h_child_inode);
+		au_fset_hinjob(flags[PARENT], DIRENT);
+		au_fset_hinjob(flags[CHILD], GEN);
+		break;
+
+	case IN_DELETE:
+		/*
+		 * aufs never be able to get this child inode.
+		 * revalidation should be in d_revalidate()
+		 * by checking i_nlink, i_generation or d_unhashed().
+		 */
+		AuDebugOn(!h_child_name);
+		au_fset_hinjob(flags[PARENT], DIRENT);
+		au_fset_hinjob(flags[CHILD], GEN);
+		au_fset_hinjob(flags[CHILD], TRYXINO0);
+		au_fset_hinjob(flags[CHILD], MNTPNT);
+		break;
+
+	default:
+		AuDebugOn(1);
+	}
+
+	if (wh)
+		h_child_inode = NULL;
+
+	/* iput() and kfree() will be called in postproc() */
+	/*
+	 * inotify_mutex is already acquired and kmalloc/prune_icache may lock
+	 * iprune_mutex. strange.
+	 */
+	lockdep_off();
+	args = kmalloc(sizeof(*args) + len + 1, GFP_NOFS);
+	lockdep_on();
+	if (unlikely(!args)) {
+		AuErr1("no memory\n");
+		iput(dir);
+		return;
+	}
+	args->flags[PARENT] = flags[PARENT];
+	args->flags[CHILD] = flags[CHILD];
+	args->mask = mask;
+	args->dir = dir;
+	args->h_dir = igrab(watch->inode);
+	if (h_child_inode)
+		h_child_inode = igrab(h_child_inode); /* can be NULL */
+	args->h_child_inode = h_child_inode;
+	args->h_child_nlen = len;
+	if (len) {
+		p = (void *)args;
+		p += sizeof(*args);
+		memcpy(p, h_child_name, len + 1);
+	}
+
+	lockdep_off();
+	wkq_err = au_wkq_nowait(postproc, args, dir->i_sb);
+	lockdep_on();
+	if (unlikely(wkq_err))
+		AuErr("wkq %d\n", wkq_err);
+}
+
+static void aufs_inotify_destroy(struct inotify_watch *watch __maybe_unused)
+{
+	return;
+}
+
+static struct inotify_operations aufs_inotify_ops = {
+	.handle_event	= aufs_inotify,
+	.destroy_watch	= aufs_inotify_destroy
+};
+
+/* ---------------------------------------------------------------------- */
+
+static void au_hin_destroy_cache(void)
+{
+	kmem_cache_destroy(au_cachep[AuCache_HINOTIFY]);
+	au_cachep[AuCache_HINOTIFY] = NULL;
+}
+
+int __init au_hinotify_init(void)
+{
+	int err;
+
+	err = -ENOMEM;
+	au_cachep[AuCache_HINOTIFY] = AuCache(au_hinotify);
+	if (au_cachep[AuCache_HINOTIFY]) {
+		err = 0;
+		au_hin_handle = inotify_init(&aufs_inotify_ops);
+		if (IS_ERR(au_hin_handle)) {
+			err = PTR_ERR(au_hin_handle);
+			au_hin_destroy_cache();
+		}
+	}
+	AuTraceErr(err);
+	return err;
+}
+
+void au_hinotify_fin(void)
+{
+	inotify_destroy(au_hin_handle);
+	if (au_cachep[AuCache_HINOTIFY])
+		au_hin_destroy_cache();
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/iinfo.c linux-2.6.31.4/fs/aufs/iinfo.c
--- linux-2.6.31.4.orig/fs/aufs/iinfo.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/iinfo.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,283 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode private data
+ */
+
+#include "aufs.h"
+
+struct inode *au_h_iptr(struct inode *inode, aufs_bindex_t bindex)
+{
+	struct inode *h_inode;
+
+	IiMustAnyLock(inode);
+
+	h_inode = au_ii(inode)->ii_hinode[0 + bindex].hi_inode;
+	AuDebugOn(h_inode && atomic_read(&h_inode->i_count) <= 0);
+	return h_inode;
+}
+
+/* todo: hard/soft set? */
+void au_set_ibstart(struct inode *inode, aufs_bindex_t bindex)
+{
+	struct au_iinfo *iinfo = au_ii(inode);
+	struct inode *h_inode;
+
+	IiMustWriteLock(inode);
+
+	iinfo->ii_bstart = bindex;
+	h_inode = iinfo->ii_hinode[bindex + 0].hi_inode;
+	if (h_inode)
+		au_cpup_igen(inode, h_inode);
+}
+
+void au_hiput(struct au_hinode *hinode)
+{
+	au_hin_free(hinode);
+	dput(hinode->hi_whdentry);
+	iput(hinode->hi_inode);
+}
+
+unsigned int au_hi_flags(struct inode *inode, int isdir)
+{
+	unsigned int flags;
+	const unsigned int mnt_flags = au_mntflags(inode->i_sb);
+
+	flags = 0;
+	if (au_opt_test(mnt_flags, XINO))
+		au_fset_hi(flags, XINO);
+	if (isdir && au_opt_test(mnt_flags, UDBA_HINOTIFY))
+		au_fset_hi(flags, HINOTIFY);
+	return flags;
+}
+
+void au_set_h_iptr(struct inode *inode, aufs_bindex_t bindex,
+		   struct inode *h_inode, unsigned int flags)
+{
+	struct au_hinode *hinode;
+	struct inode *hi;
+	struct au_iinfo *iinfo = au_ii(inode);
+
+	IiMustWriteLock(inode);
+
+	hinode = iinfo->ii_hinode + bindex;
+	hi = hinode->hi_inode;
+	AuDebugOn(h_inode && atomic_read(&h_inode->i_count) <= 0);
+	AuDebugOn(h_inode && hi);
+
+	if (hi)
+		au_hiput(hinode);
+	hinode->hi_inode = h_inode;
+	if (h_inode) {
+		int err;
+		struct super_block *sb = inode->i_sb;
+		struct au_branch *br;
+
+		if (bindex == iinfo->ii_bstart)
+			au_cpup_igen(inode, h_inode);
+		br = au_sbr(sb, bindex);
+		hinode->hi_id = br->br_id;
+		if (au_ftest_hi(flags, XINO)) {
+			err = au_xino_write(sb, bindex, h_inode->i_ino,
+					    inode->i_ino);
+			if (unlikely(err))
+				AuIOErr1("failed au_xino_write() %d\n", err);
+		}
+
+		if (au_ftest_hi(flags, HINOTIFY)
+		    && au_br_hinotifyable(br->br_perm)) {
+			err = au_hin_alloc(hinode, inode, h_inode);
+			if (unlikely(err))
+				AuIOErr1("au_hin_alloc() %d\n", err);
+		}
+	}
+}
+
+void au_set_hi_wh(struct inode *inode, aufs_bindex_t bindex,
+		  struct dentry *h_wh)
+{
+	struct au_hinode *hinode;
+
+	IiMustWriteLock(inode);
+
+	hinode = au_ii(inode)->ii_hinode + bindex;
+	AuDebugOn(hinode->hi_whdentry);
+	hinode->hi_whdentry = h_wh;
+}
+
+void au_update_iigen(struct inode *inode)
+{
+	atomic_set(&au_ii(inode)->ii_generation, au_sigen(inode->i_sb));
+	/* smp_mb(); */ /* atomic_set */
+}
+
+/* it may be called at remount time, too */
+void au_update_brange(struct inode *inode, int do_put_zero)
+{
+	struct au_iinfo *iinfo;
+
+	iinfo = au_ii(inode);
+	if (!iinfo || iinfo->ii_bstart < 0)
+		return;
+
+	IiMustWriteLock(inode);
+
+	if (do_put_zero) {
+		aufs_bindex_t bindex;
+
+		for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend;
+		     bindex++) {
+			struct inode *h_i;
+
+			h_i = iinfo->ii_hinode[0 + bindex].hi_inode;
+			if (h_i && !h_i->i_nlink)
+				au_set_h_iptr(inode, bindex, NULL, 0);
+		}
+	}
+
+	iinfo->ii_bstart = -1;
+	while (++iinfo->ii_bstart <= iinfo->ii_bend)
+		if (iinfo->ii_hinode[0 + iinfo->ii_bstart].hi_inode)
+			break;
+	if (iinfo->ii_bstart > iinfo->ii_bend) {
+		iinfo->ii_bstart = -1;
+		iinfo->ii_bend = -1;
+		return;
+	}
+
+	iinfo->ii_bend++;
+	while (0 <= --iinfo->ii_bend)
+		if (iinfo->ii_hinode[0 + iinfo->ii_bend].hi_inode)
+			break;
+	AuDebugOn(iinfo->ii_bstart > iinfo->ii_bend || iinfo->ii_bend < 0);
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_iinfo_init(struct inode *inode)
+{
+	struct au_iinfo *iinfo;
+	struct super_block *sb;
+	int nbr, i;
+
+	sb = inode->i_sb;
+	iinfo = &(container_of(inode, struct au_icntnr, vfs_inode)->iinfo);
+	nbr = au_sbend(sb) + 1;
+	if (unlikely(nbr <= 0))
+		nbr = 1;
+	iinfo->ii_hinode = kcalloc(nbr, sizeof(*iinfo->ii_hinode), GFP_NOFS);
+	if (iinfo->ii_hinode) {
+		for (i = 0; i < nbr; i++)
+			iinfo->ii_hinode[i].hi_id = -1;
+
+		atomic_set(&iinfo->ii_generation, au_sigen(sb));
+		/* smp_mb(); */ /* atomic_set */
+		au_rw_init(&iinfo->ii_rwsem);
+		iinfo->ii_bstart = -1;
+		iinfo->ii_bend = -1;
+		iinfo->ii_vdir = NULL;
+		return 0;
+	}
+	return -ENOMEM;
+}
+
+int au_ii_realloc(struct au_iinfo *iinfo, int nbr)
+{
+	int err, sz;
+	struct au_hinode *hip;
+
+	AuRwMustWriteLock(&iinfo->ii_rwsem);
+
+	err = -ENOMEM;
+	sz = sizeof(*hip) * (iinfo->ii_bend + 1);
+	if (!sz)
+		sz = sizeof(*hip);
+	hip = au_kzrealloc(iinfo->ii_hinode, sz, sizeof(*hip) * nbr, GFP_NOFS);
+	if (hip) {
+		iinfo->ii_hinode = hip;
+		err = 0;
+	}
+
+	return err;
+}
+
+static int au_iinfo_write0(struct super_block *sb, struct au_hinode *hinode,
+			   ino_t ino)
+{
+	int err;
+	aufs_bindex_t bindex;
+	unsigned char locked;
+
+	err = 0;
+	locked = !!si_noflush_read_trylock(sb);
+	bindex = au_br_index(sb, hinode->hi_id);
+	if (bindex >= 0)
+		err = au_xino_write0(sb, bindex, hinode->hi_inode->i_ino, ino);
+	/* error action? */
+	if (locked)
+		si_read_unlock(sb);
+	return err;
+}
+
+void au_iinfo_fin(struct inode *inode)
+{
+	ino_t ino;
+	aufs_bindex_t bend;
+	unsigned char unlinked = !inode->i_nlink;
+	struct au_iinfo *iinfo;
+	struct au_hinode *hi;
+	struct super_block *sb;
+
+	if (unlinked) {
+		int err = au_xigen_inc(inode);
+		if (unlikely(err))
+			AuWarn1("failed resetting i_generation, %d\n", err);
+	}
+
+	iinfo = au_ii(inode);
+	/* bad_inode case */
+	if (!iinfo)
+		return;
+
+	if (iinfo->ii_vdir)
+		au_vdir_free(iinfo->ii_vdir);
+
+	if (iinfo->ii_bstart >= 0) {
+		sb = inode->i_sb;
+		ino = 0;
+		if (unlinked)
+			ino = inode->i_ino;
+		hi = iinfo->ii_hinode + iinfo->ii_bstart;
+		bend = iinfo->ii_bend;
+		while (iinfo->ii_bstart++ <= bend) {
+			if (hi->hi_inode) {
+				if (unlinked || !hi->hi_inode->i_nlink) {
+					au_iinfo_write0(sb, hi, ino);
+					/* ignore this error */
+					ino = 0;
+				}
+				au_hiput(hi);
+			}
+			hi++;
+		}
+	}
+
+	kfree(iinfo->ii_hinode);
+	AuRwDestroy(&iinfo->ii_rwsem);
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/inode.c linux-2.6.31.4/fs/aufs/inode.c
--- linux-2.6.31.4.orig/fs/aufs/inode.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/inode.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,380 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode functions
+ */
+
+#include "aufs.h"
+
+struct inode *au_igrab(struct inode *inode)
+{
+	if (inode) {
+		AuDebugOn(!atomic_read(&inode->i_count));
+		atomic_inc_return(&inode->i_count);
+	}
+	return inode;
+}
+
+static void au_refresh_hinode_attr(struct inode *inode, int do_version)
+{
+	au_cpup_attr_all(inode, /*force*/0);
+	au_update_iigen(inode);
+	if (do_version)
+		inode->i_version++;
+}
+
+int au_refresh_hinode_self(struct inode *inode, int do_attr)
+{
+	int err;
+	aufs_bindex_t bindex, new_bindex;
+	unsigned char update;
+	struct inode *first;
+	struct au_hinode *p, *q, tmp;
+	struct super_block *sb;
+	struct au_iinfo *iinfo;
+
+	IiMustWriteLock(inode);
+
+	update = 0;
+	sb = inode->i_sb;
+	iinfo = au_ii(inode);
+	err = au_ii_realloc(iinfo, au_sbend(sb) + 1);
+	if (unlikely(err))
+		goto out;
+
+	p = iinfo->ii_hinode + iinfo->ii_bstart;
+	first = p->hi_inode;
+	err = 0;
+	for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend;
+	     bindex++, p++) {
+		if (!p->hi_inode)
+			continue;
+
+		new_bindex = au_br_index(sb, p->hi_id);
+		if (new_bindex == bindex)
+			continue;
+
+		if (new_bindex < 0) {
+			update++;
+			au_hiput(p);
+			p->hi_inode = NULL;
+			continue;
+		}
+
+		if (new_bindex < iinfo->ii_bstart)
+			iinfo->ii_bstart = new_bindex;
+		if (iinfo->ii_bend < new_bindex)
+			iinfo->ii_bend = new_bindex;
+		/* swap two lower inode, and loop again */
+		q = iinfo->ii_hinode + new_bindex;
+		tmp = *q;
+		*q = *p;
+		*p = tmp;
+		if (tmp.hi_inode) {
+			bindex--;
+			p--;
+		}
+	}
+	au_update_brange(inode, /*do_put_zero*/0);
+	if (do_attr)
+		au_refresh_hinode_attr(inode, update && S_ISDIR(inode->i_mode));
+
+ out:
+	return err;
+}
+
+int au_refresh_hinode(struct inode *inode, struct dentry *dentry)
+{
+	int err, update;
+	unsigned int flags;
+	aufs_bindex_t bindex, bend;
+	unsigned char isdir;
+	struct inode *first;
+	struct au_hinode *p;
+	struct au_iinfo *iinfo;
+
+	err = au_refresh_hinode_self(inode, /*do_attr*/0);
+	if (unlikely(err))
+		goto out;
+
+	update = 0;
+	iinfo = au_ii(inode);
+	p = iinfo->ii_hinode + iinfo->ii_bstart;
+	first = p->hi_inode;
+	isdir = S_ISDIR(inode->i_mode);
+	flags = au_hi_flags(inode, isdir);
+	bend = au_dbend(dentry);
+	for (bindex = au_dbstart(dentry); bindex <= bend; bindex++) {
+		struct inode *h_i;
+		struct dentry *h_d;
+
+		h_d = au_h_dptr(dentry, bindex);
+		if (!h_d || !h_d->d_inode)
+			continue;
+
+		if (iinfo->ii_bstart <= bindex && bindex <= iinfo->ii_bend) {
+			h_i = au_h_iptr(inode, bindex);
+			if (h_i) {
+				if (h_i == h_d->d_inode)
+					continue;
+				err = -EIO;
+				break;
+			}
+		}
+		if (bindex < iinfo->ii_bstart)
+			iinfo->ii_bstart = bindex;
+		if (iinfo->ii_bend < bindex)
+			iinfo->ii_bend = bindex;
+		au_set_h_iptr(inode, bindex, au_igrab(h_d->d_inode), flags);
+		update = 1;
+	}
+	au_update_brange(inode, /*do_put_zero*/0);
+
+	if (unlikely(err))
+		goto out;
+
+	au_refresh_hinode_attr(inode, update && isdir);
+
+ out:
+	return err;
+}
+
+static int set_inode(struct inode *inode, struct dentry *dentry)
+{
+	int err;
+	unsigned int flags;
+	umode_t mode;
+	aufs_bindex_t bindex, bstart, btail;
+	unsigned char isdir;
+	struct dentry *h_dentry;
+	struct inode *h_inode;
+	struct au_iinfo *iinfo;
+
+	IiMustWriteLock(inode);
+
+	err = 0;
+	isdir = 0;
+	bstart = au_dbstart(dentry);
+	h_inode = au_h_dptr(dentry, bstart)->d_inode;
+	mode = h_inode->i_mode;
+	switch (mode & S_IFMT) {
+	case S_IFREG:
+		btail = au_dbtail(dentry);
+		inode->i_op = &aufs_iop;
+		inode->i_fop = &aufs_file_fop;
+		inode->i_mapping->a_ops = &aufs_aop;
+		break;
+	case S_IFDIR:
+		isdir = 1;
+		btail = au_dbtaildir(dentry);
+		inode->i_op = &aufs_dir_iop;
+		inode->i_fop = &aufs_dir_fop;
+		break;
+	case S_IFLNK:
+		btail = au_dbtail(dentry);
+		inode->i_op = &aufs_symlink_iop;
+		break;
+	case S_IFBLK:
+	case S_IFCHR:
+	case S_IFIFO:
+	case S_IFSOCK:
+		btail = au_dbtail(dentry);
+		inode->i_op = &aufs_iop;
+		init_special_inode(inode, mode, h_inode->i_rdev);
+		break;
+	default:
+		AuIOErr("Unknown file type 0%o\n", mode);
+		err = -EIO;
+		goto out;
+	}
+
+	/* do not set inotify for whiteouted dirs (SHWH mode) */
+	flags = au_hi_flags(inode, isdir);
+	if (au_opt_test(au_mntflags(dentry->d_sb), SHWH)
+	    && au_ftest_hi(flags, HINOTIFY)
+	    && dentry->d_name.len > AUFS_WH_PFX_LEN
+	    && !memcmp(dentry->d_name.name, AUFS_WH_PFX, AUFS_WH_PFX_LEN))
+		au_fclr_hi(flags, HINOTIFY);
+	iinfo = au_ii(inode);
+	iinfo->ii_bstart = bstart;
+	iinfo->ii_bend = btail;
+	for (bindex = bstart; bindex <= btail; bindex++) {
+		h_dentry = au_h_dptr(dentry, bindex);
+		if (h_dentry)
+			au_set_h_iptr(inode, bindex,
+				      au_igrab(h_dentry->d_inode), flags);
+	}
+	au_cpup_attr_all(inode, /*force*/1);
+
+ out:
+	return err;
+}
+
+/* successful returns with iinfo write_locked */
+static int reval_inode(struct inode *inode, struct dentry *dentry, int *matched)
+{
+	int err;
+	aufs_bindex_t bindex, bend;
+	struct inode *h_inode, *h_dinode;
+
+	*matched = 0;
+
+	/*
+	 * before this function, if aufs got any iinfo lock, it must be only
+	 * one, the parent dir.
+	 * it can happen by UDBA and the obsoleted inode number.
+	 */
+	err = -EIO;
+	if (unlikely(inode->i_ino == parent_ino(dentry)))
+		goto out;
+
+	err = 0;
+	ii_write_lock_new_child(inode);
+	h_dinode = au_h_dptr(dentry, au_dbstart(dentry))->d_inode;
+	bend = au_ibend(inode);
+	for (bindex = au_ibstart(inode); bindex <= bend; bindex++) {
+		h_inode = au_h_iptr(inode, bindex);
+		if (h_inode && h_inode == h_dinode) {
+			*matched = 1;
+			err = 0;
+			if (au_iigen(inode) != au_digen(dentry))
+				err = au_refresh_hinode(inode, dentry);
+			break;
+		}
+	}
+
+	if (unlikely(err))
+		ii_write_unlock(inode);
+ out:
+	return err;
+}
+
+/* successful returns with iinfo write_locked */
+/* todo: return with unlocked? */
+struct inode *au_new_inode(struct dentry *dentry, int must_new)
+{
+	struct inode *inode;
+	struct dentry *h_dentry;
+	struct super_block *sb;
+	ino_t h_ino, ino;
+	int err, match;
+	aufs_bindex_t bstart;
+
+	sb = dentry->d_sb;
+	bstart = au_dbstart(dentry);
+	h_dentry = au_h_dptr(dentry, bstart);
+	h_ino = h_dentry->d_inode->i_ino;
+	err = au_xino_read(sb, bstart, h_ino, &ino);
+	inode = ERR_PTR(err);
+	if (unlikely(err))
+		goto out;
+ new_ino:
+	if (!ino) {
+		ino = au_xino_new_ino(sb);
+		if (unlikely(!ino)) {
+			inode = ERR_PTR(-EIO);
+			goto out;
+		}
+	}
+
+	AuDbg("i%lu\n", (unsigned long)ino);
+	inode = au_iget_locked(sb, ino);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out;
+
+	AuDbg("%lx, new %d\n", inode->i_state, !!(inode->i_state & I_NEW));
+	if (inode->i_state & I_NEW) {
+		ii_write_lock_new_child(inode);
+		err = set_inode(inode, dentry);
+		unlock_new_inode(inode);
+		if (!err)
+			goto out; /* success */
+
+		iget_failed(inode);
+		ii_write_unlock(inode);
+		goto out_iput;
+	} else if (!must_new) {
+		err = reval_inode(inode, dentry, &match);
+		if (!err)
+			goto out; /* success */
+		else if (match)
+			goto out_iput;
+	}
+
+	if (unlikely(au_test_fs_unique_ino(h_dentry->d_inode)))
+		AuWarn1("Warning: Un-notified UDBA or repeatedly renamed dir,"
+			" b%d, %s, %.*s, hi%lu, i%lu.\n",
+			bstart, au_sbtype(h_dentry->d_sb), AuDLNPair(dentry),
+			(unsigned long)h_ino, (unsigned long)ino);
+	ino = 0;
+	err = au_xino_write(sb, bstart, h_ino, /*ino*/0);
+	if (!err) {
+		iput(inode);
+		goto new_ino;
+	}
+
+ out_iput:
+	iput(inode);
+	inode = ERR_PTR(err);
+ out:
+	return inode;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,
+	       struct inode *inode)
+{
+	int err;
+
+	err = au_br_rdonly(au_sbr(sb, bindex));
+
+	/* pseudo-link after flushed may happen out of bounds */
+	if (!err
+	    && inode
+	    && au_ibstart(inode) <= bindex
+	    && bindex <= au_ibend(inode)) {
+		/*
+		 * permission check is unnecessary since vfsub routine
+		 * will be called later
+		 */
+		struct inode *hi = au_h_iptr(inode, bindex);
+		if (hi)
+			err = IS_IMMUTABLE(hi) ? -EROFS : 0;
+	}
+
+	return err;
+}
+
+int au_test_h_perm(struct inode *h_inode, int mask)
+{
+	if (!current_fsuid())
+		return 0;
+	return inode_permission(h_inode, mask);
+}
+
+int au_test_h_perm_sio(struct inode *h_inode, int mask)
+{
+	if (au_test_nfs(h_inode->i_sb)
+	    && (mask & MAY_WRITE)
+	    && S_ISDIR(h_inode->i_mode))
+		mask |= MAY_READ; /* force permission check */
+	return au_test_h_perm(h_inode, mask);
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/inode.h linux-2.6.31.4/fs/aufs/inode.h
--- linux-2.6.31.4.orig/fs/aufs/inode.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/inode.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,484 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode operations
+ */
+
+#ifndef __AUFS_INODE_H__
+#define __AUFS_INODE_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/inotify.h>
+#include <linux/aufs_type.h>
+#include "rwsem.h"
+
+struct vfsmount;
+
+struct au_hinotify {
+#ifdef CONFIG_AUFS_HINOTIFY
+	struct inotify_watch	hin_watch;
+	struct inode		*hin_aufs_inode;	/* no get/put */
+#endif
+};
+
+struct au_hinode {
+	struct inode		*hi_inode;
+	aufs_bindex_t		hi_id;
+#ifdef CONFIG_AUFS_HINOTIFY
+	struct au_hinotify	*hi_notify;
+#endif
+
+	/* reference to the copied-up whiteout with get/put */
+	struct dentry		*hi_whdentry;
+};
+
+struct au_vdir;
+struct au_iinfo {
+	atomic_t		ii_generation;
+	struct super_block	*ii_hsb1;	/* no get/put */
+
+	struct au_rwsem		ii_rwsem;
+	aufs_bindex_t		ii_bstart, ii_bend;
+	__u32			ii_higen;
+	struct au_hinode	*ii_hinode;
+	struct au_vdir		*ii_vdir;
+};
+
+struct au_icntnr {
+	struct au_iinfo iinfo;
+	struct inode vfs_inode;
+};
+
+/* au_pin flags */
+#define AuPin_DI_LOCKED		1
+#define AuPin_MNT_WRITE		(1 << 1)
+#define au_ftest_pin(flags, name)	((flags) & AuPin_##name)
+#define au_fset_pin(flags, name)	{ (flags) |= AuPin_##name; }
+#define au_fclr_pin(flags, name)	{ (flags) &= ~AuPin_##name; }
+
+struct au_pin {
+	/* input */
+	struct dentry *dentry;
+	unsigned int udba;
+	unsigned char lsc_di, lsc_hi, flags;
+	aufs_bindex_t bindex;
+
+	/* output */
+	struct dentry *parent;
+	struct au_hinode *hdir;
+	struct vfsmount *h_mnt;
+};
+
+/* ---------------------------------------------------------------------- */
+
+static inline struct au_iinfo *au_ii(struct inode *inode)
+{
+	struct au_iinfo *iinfo;
+
+	iinfo = &(container_of(inode, struct au_icntnr, vfs_inode)->iinfo);
+	if (iinfo->ii_hinode)
+		return iinfo;
+	return NULL; /* debugging bad_inode case */
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* inode.c */
+struct inode *au_igrab(struct inode *inode);
+int au_refresh_hinode_self(struct inode *inode, int do_attr);
+int au_refresh_hinode(struct inode *inode, struct dentry *dentry);
+struct inode *au_new_inode(struct dentry *dentry, int must_new);
+int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,
+	       struct inode *inode);
+int au_test_h_perm(struct inode *h_inode, int mask);
+int au_test_h_perm_sio(struct inode *h_inode, int mask);
+
+/* i_op.c */
+extern struct inode_operations aufs_iop, aufs_symlink_iop, aufs_dir_iop;
+
+/* au_wr_dir flags */
+#define AuWrDir_ADD_ENTRY	1
+#define AuWrDir_ISDIR		(1 << 1)
+#define au_ftest_wrdir(flags, name)	((flags) & AuWrDir_##name)
+#define au_fset_wrdir(flags, name)	{ (flags) |= AuWrDir_##name; }
+#define au_fclr_wrdir(flags, name)	{ (flags) &= ~AuWrDir_##name; }
+
+struct au_wr_dir_args {
+	aufs_bindex_t force_btgt;
+	unsigned char flags;
+};
+int au_wr_dir(struct dentry *dentry, struct dentry *src_dentry,
+	      struct au_wr_dir_args *args);
+
+struct dentry *au_pinned_h_parent(struct au_pin *pin);
+void au_pin_init(struct au_pin *pin, struct dentry *dentry,
+		 aufs_bindex_t bindex, int lsc_di, int lsc_hi,
+		 unsigned int udba, unsigned char flags);
+int au_pin(struct au_pin *pin, struct dentry *dentry, aufs_bindex_t bindex,
+	   unsigned int udba, unsigned char flags) __must_check;
+int au_do_pin(struct au_pin *pin) __must_check;
+void au_unpin(struct au_pin *pin);
+
+/* i_op_add.c */
+int au_may_add(struct dentry *dentry, aufs_bindex_t bindex,
+	       struct dentry *h_parent, int isdir);
+int aufs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev);
+int aufs_symlink(struct inode *dir, struct dentry *dentry, const char *symname);
+int aufs_create(struct inode *dir, struct dentry *dentry, int mode,
+		struct nameidata *nd);
+int aufs_link(struct dentry *src_dentry, struct inode *dir,
+	      struct dentry *dentry);
+int aufs_mkdir(struct inode *dir, struct dentry *dentry, int mode);
+
+/* i_op_del.c */
+int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup);
+int au_may_del(struct dentry *dentry, aufs_bindex_t bindex,
+	       struct dentry *h_parent, int isdir);
+int aufs_unlink(struct inode *dir, struct dentry *dentry);
+int aufs_rmdir(struct inode *dir, struct dentry *dentry);
+
+/* i_op_ren.c */
+int au_wbr(struct dentry *dentry, aufs_bindex_t btgt);
+int aufs_rename(struct inode *src_dir, struct dentry *src_dentry,
+		struct inode *dir, struct dentry *dentry);
+
+/* iinfo.c */
+struct inode *au_h_iptr(struct inode *inode, aufs_bindex_t bindex);
+void au_hiput(struct au_hinode *hinode);
+void au_set_ibstart(struct inode *inode, aufs_bindex_t bindex);
+void au_set_hi_wh(struct inode *inode, aufs_bindex_t bindex,
+		  struct dentry *h_wh);
+unsigned int au_hi_flags(struct inode *inode, int isdir);
+
+/* hinode flags */
+#define AuHi_XINO	1
+#define AuHi_HINOTIFY	(1 << 1)
+#define au_ftest_hi(flags, name)	((flags) & AuHi_##name)
+#define au_fset_hi(flags, name)		{ (flags) |= AuHi_##name; }
+#define au_fclr_hi(flags, name)		{ (flags) &= ~AuHi_##name; }
+
+#ifndef CONFIG_AUFS_HINOTIFY
+#undef AuHi_HINOTIFY
+#define AuHi_HINOTIFY	0
+#endif
+
+void au_set_h_iptr(struct inode *inode, aufs_bindex_t bindex,
+		   struct inode *h_inode, unsigned int flags);
+
+void au_update_iigen(struct inode *inode);
+void au_update_brange(struct inode *inode, int do_put_zero);
+
+int au_iinfo_init(struct inode *inode);
+void au_iinfo_fin(struct inode *inode);
+int au_ii_realloc(struct au_iinfo *iinfo, int nbr);
+
+/* plink.c */
+void au_plink_block_maintain(struct super_block *sb);
+#ifdef CONFIG_AUFS_DEBUG
+void au_plink_list(struct super_block *sb);
+#else
+static inline void au_plink_list(struct super_block *sb)
+{
+	/* nothing */
+}
+#endif
+int au_plink_test(struct inode *inode);
+struct dentry *au_plink_lkup(struct inode *inode, aufs_bindex_t bindex);
+void au_plink_append(struct inode *inode, aufs_bindex_t bindex,
+		     struct dentry *h_dentry);
+void au_plink_put(struct super_block *sb);
+void au_plink_half_refresh(struct super_block *sb, aufs_bindex_t br_id);
+
+/* ---------------------------------------------------------------------- */
+
+/* lock subclass for iinfo */
+enum {
+	AuLsc_II_CHILD,		/* child first */
+	AuLsc_II_CHILD2,	/* rename(2), link(2), and cpup at hinotify */
+	AuLsc_II_CHILD3,	/* copyup dirs */
+	AuLsc_II_PARENT,	/* see AuLsc_I_PARENT in vfsub.h */
+	AuLsc_II_PARENT2,
+	AuLsc_II_PARENT3,	/* copyup dirs */
+	AuLsc_II_NEW_CHILD
+};
+
+/*
+ * ii_read_lock_child, ii_write_lock_child,
+ * ii_read_lock_child2, ii_write_lock_child2,
+ * ii_read_lock_child3, ii_write_lock_child3,
+ * ii_read_lock_parent, ii_write_lock_parent,
+ * ii_read_lock_parent2, ii_write_lock_parent2,
+ * ii_read_lock_parent3, ii_write_lock_parent3,
+ * ii_read_lock_new_child, ii_write_lock_new_child,
+ */
+#define AuReadLockFunc(name, lsc) \
+static inline void ii_read_lock_##name(struct inode *i) \
+{ \
+	au_rw_read_lock_nested(&au_ii(i)->ii_rwsem, AuLsc_II_##lsc); \
+}
+
+#define AuWriteLockFunc(name, lsc) \
+static inline void ii_write_lock_##name(struct inode *i) \
+{ \
+	au_rw_write_lock_nested(&au_ii(i)->ii_rwsem, AuLsc_II_##lsc); \
+}
+
+#define AuRWLockFuncs(name, lsc) \
+	AuReadLockFunc(name, lsc) \
+	AuWriteLockFunc(name, lsc)
+
+AuRWLockFuncs(child, CHILD);
+AuRWLockFuncs(child2, CHILD2);
+AuRWLockFuncs(child3, CHILD3);
+AuRWLockFuncs(parent, PARENT);
+AuRWLockFuncs(parent2, PARENT2);
+AuRWLockFuncs(parent3, PARENT3);
+AuRWLockFuncs(new_child, NEW_CHILD);
+
+#undef AuReadLockFunc
+#undef AuWriteLockFunc
+#undef AuRWLockFuncs
+
+/*
+ * ii_read_unlock, ii_write_unlock, ii_downgrade_lock
+ */
+AuSimpleUnlockRwsemFuncs(ii, struct inode *i, &au_ii(i)->ii_rwsem);
+
+#define IiMustNoWaiters(i)	AuRwMustNoWaiters(&au_ii(i)->ii_rwsem)
+#define IiMustAnyLock(i)	AuRwMustAnyLock(&au_ii(i)->ii_rwsem)
+#define IiMustWriteLock(i)	AuRwMustWriteLock(&au_ii(i)->ii_rwsem)
+
+/* ---------------------------------------------------------------------- */
+
+static inline unsigned int au_iigen(struct inode *inode)
+{
+	return atomic_read(&au_ii(inode)->ii_generation);
+}
+
+/* tiny test for inode number */
+/* tmpfs generation is too rough */
+static inline int au_test_higen(struct inode *inode, struct inode *h_inode)
+{
+	struct au_iinfo *iinfo;
+
+	iinfo = au_ii(inode);
+	AuRwMustAnyLock(&iinfo->ii_rwsem);
+	return !(iinfo->ii_hsb1 == h_inode->i_sb
+		 && iinfo->ii_higen == h_inode->i_generation);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static inline aufs_bindex_t au_ii_br_id(struct inode *inode,
+					aufs_bindex_t bindex)
+{
+	IiMustAnyLock(inode);
+	return au_ii(inode)->ii_hinode[0 + bindex].hi_id;
+}
+
+static inline aufs_bindex_t au_ibstart(struct inode *inode)
+{
+	IiMustAnyLock(inode);
+	return au_ii(inode)->ii_bstart;
+}
+
+static inline aufs_bindex_t au_ibend(struct inode *inode)
+{
+	IiMustAnyLock(inode);
+	return au_ii(inode)->ii_bend;
+}
+
+static inline struct au_vdir *au_ivdir(struct inode *inode)
+{
+	IiMustAnyLock(inode);
+	return au_ii(inode)->ii_vdir;
+}
+
+static inline struct dentry *au_hi_wh(struct inode *inode, aufs_bindex_t bindex)
+{
+	IiMustAnyLock(inode);
+	return au_ii(inode)->ii_hinode[0 + bindex].hi_whdentry;
+}
+
+static inline void au_set_ibend(struct inode *inode, aufs_bindex_t bindex)
+{
+	IiMustWriteLock(inode);
+	au_ii(inode)->ii_bend = bindex;
+}
+
+static inline void au_set_ivdir(struct inode *inode, struct au_vdir *vdir)
+{
+	IiMustWriteLock(inode);
+	au_ii(inode)->ii_vdir = vdir;
+}
+
+static inline struct au_hinode *au_hi(struct inode *inode, aufs_bindex_t bindex)
+{
+	IiMustAnyLock(inode);
+	return au_ii(inode)->ii_hinode + bindex;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static inline struct dentry *au_pinned_parent(struct au_pin *pin)
+{
+	if (pin)
+		return pin->parent;
+	return NULL;
+}
+
+static inline struct inode *au_pinned_h_dir(struct au_pin *pin)
+{
+	if (pin && pin->hdir)
+		return pin->hdir->hi_inode;
+	return NULL;
+}
+
+static inline struct au_hinode *au_pinned_hdir(struct au_pin *pin)
+{
+	if (pin)
+		return pin->hdir;
+	return NULL;
+}
+
+static inline void au_pin_set_dentry(struct au_pin *pin, struct dentry *dentry)
+{
+	if (pin)
+		pin->dentry = dentry;
+}
+
+static inline void au_pin_set_parent_lflag(struct au_pin *pin,
+					   unsigned char lflag)
+{
+	if (pin) {
+		/* dirty macros require brackets */
+		if (lflag) {
+			au_fset_pin(pin->flags, DI_LOCKED);
+		} else {
+			au_fclr_pin(pin->flags, DI_LOCKED);
+		}
+	}
+}
+
+static inline void au_pin_set_parent(struct au_pin *pin, struct dentry *parent)
+{
+	if (pin) {
+		dput(pin->parent);
+		pin->parent = dget(parent);
+	}
+}
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_HINOTIFY
+/* hinotify.c */
+int au_hin_alloc(struct au_hinode *hinode, struct inode *inode,
+		 struct inode *h_inode);
+void au_hin_free(struct au_hinode *hinode);
+void au_hin_ctl(struct au_hinode *hinode, int do_set);
+void au_reset_hinotify(struct inode *inode, unsigned int flags);
+
+int __init au_hinotify_init(void);
+void au_hinotify_fin(void);
+
+static inline
+void au_hin_init(struct au_hinode *hinode, struct au_hinotify *val)
+{
+	hinode->hi_notify = val;
+}
+
+static inline void au_iigen_dec(struct inode *inode)
+{
+	atomic_dec_return(&au_ii(inode)->ii_generation);
+}
+
+#else
+static inline
+int au_hin_alloc(struct au_hinode *hinode __maybe_unused,
+		 struct inode *inode __maybe_unused,
+		 struct inode *h_inode __maybe_unused)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void au_hin_free(struct au_hinode *hinode __maybe_unused)
+{
+	/* nothing */
+}
+
+static inline void au_hin_ctl(struct au_hinode *hinode __maybe_unused,
+			      int do_set __maybe_unused)
+{
+	/* nothing */
+}
+
+static inline void au_reset_hinotify(struct inode *inode __maybe_unused,
+				     unsigned int flags __maybe_unused)
+{
+	/* nothing */
+}
+
+static inline int au_hinotify_init(void)
+{
+	return 0;
+}
+
+#define au_hinotify_fin()	do {} while (0)
+
+static inline
+void au_hin_init(struct au_hinode *hinode __maybe_unused,
+		 struct au_hinotify *val __maybe_unused)
+{
+	/* empty */
+}
+#endif /* CONFIG_AUFS_HINOTIFY */
+
+static inline void au_hin_suspend(struct au_hinode *hdir)
+{
+	au_hin_ctl(hdir, /*do_set*/0);
+}
+
+static inline void au_hin_resume(struct au_hinode *hdir)
+{
+	au_hin_ctl(hdir, /*do_set*/1);
+}
+
+static inline void au_hin_imtx_lock(struct au_hinode *hdir)
+{
+	mutex_lock(&hdir->hi_inode->i_mutex);
+	au_hin_suspend(hdir);
+}
+
+static inline void au_hin_imtx_lock_nested(struct au_hinode *hdir,
+					   unsigned int sc __maybe_unused)
+{
+	mutex_lock_nested(&hdir->hi_inode->i_mutex, sc);
+	au_hin_suspend(hdir);
+}
+
+static inline void au_hin_imtx_unlock(struct au_hinode *hdir)
+{
+	au_hin_resume(hdir);
+	mutex_unlock(&hdir->hi_inode->i_mutex);
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_INODE_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/ioctl.c linux-2.6.31.4/fs/aufs/ioctl.c
--- linux-2.6.31.4.orig/fs/aufs/ioctl.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/ioctl.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * ioctl
+ * currently plink-management only.
+ */
+
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+long aufs_ioctl_dir(struct file *file, unsigned int cmd,
+		    unsigned long arg __maybe_unused)
+{
+	long err;
+	struct super_block *sb;
+	struct au_sbinfo *sbinfo;
+
+	err = -EACCES;
+	if (!capable(CAP_SYS_ADMIN))
+		goto out;
+
+	err = 0;
+	sb = file->f_dentry->d_sb;
+	sbinfo = au_sbi(sb);
+	switch (cmd) {
+	case AUFS_CTL_PLINK_MAINT:
+		/*
+		 * pseudo-link maintenance mode,
+		 * cleared by aufs_release_dir()
+		 */
+		si_write_lock(sb);
+		if (!au_ftest_si(sbinfo, MAINTAIN_PLINK)) {
+			au_fset_si(sbinfo, MAINTAIN_PLINK);
+			au_fi(file)->fi_maintain_plink = 1;
+		} else
+			err = -EBUSY;
+		si_write_unlock(sb);
+		break;
+	case AUFS_CTL_PLINK_CLEAN:
+		aufs_write_lock(sb->s_root);
+		if (au_opt_test(sbinfo->si_mntflags, PLINK))
+			au_plink_put(sb);
+		aufs_write_unlock(sb->s_root);
+		break;
+	default:
+		err = -EINVAL;
+	}
+
+ out:
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/i_op_add.c linux-2.6.31.4/fs/aufs/i_op_add.c
--- linux-2.6.31.4.orig/fs/aufs/i_op_add.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/i_op_add.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,649 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode operations (add entry)
+ */
+
+#include "aufs.h"
+
+/*
+ * final procedure of adding a new entry, except link(2).
+ * remove whiteout, instantiate, copyup the parent dir's times and size
+ * and update version.
+ * if it failed, re-create the removed whiteout.
+ */
+static int epilog(struct inode *dir, aufs_bindex_t bindex,
+		  struct dentry *wh_dentry, struct dentry *dentry)
+{
+	int err, rerr;
+	aufs_bindex_t bwh;
+	struct path h_path;
+	struct inode *inode, *h_dir;
+	struct dentry *wh;
+
+	bwh = -1;
+	if (wh_dentry) {
+		h_dir = wh_dentry->d_parent->d_inode; /* dir inode is locked */
+		IMustLock(h_dir);
+		AuDebugOn(au_h_iptr(dir, bindex) != h_dir);
+		bwh = au_dbwh(dentry);
+		h_path.dentry = wh_dentry;
+		h_path.mnt = au_sbr_mnt(dir->i_sb, bindex);
+		err = au_wh_unlink_dentry(au_h_iptr(dir, bindex), &h_path,
+					  dentry);
+		if (unlikely(err))
+			goto out;
+	}
+
+	inode = au_new_inode(dentry, /*must_new*/1);
+	if (!IS_ERR(inode)) {
+		d_instantiate(dentry, inode);
+		dir = dentry->d_parent->d_inode; /* dir inode is locked */
+		IMustLock(dir);
+		if (au_ibstart(dir) == au_dbstart(dentry))
+			au_cpup_attr_timesizes(dir);
+		dir->i_version++;
+		return 0; /* success */
+	}
+
+	err = PTR_ERR(inode);
+	if (!wh_dentry)
+		goto out;
+
+	/* revert */
+	/* dir inode is locked */
+	wh = au_wh_create(dentry, bwh, wh_dentry->d_parent);
+	rerr = PTR_ERR(wh);
+	if (IS_ERR(wh)) {
+		AuIOErr("%.*s reverting whiteout failed(%d, %d)\n",
+			AuDLNPair(dentry), err, rerr);
+		err = -EIO;
+	} else
+		dput(wh);
+
+ out:
+	return err;
+}
+
+/*
+ * simple tests for the adding inode operations.
+ * following the checks in vfs, plus the parent-child relationship.
+ */
+int au_may_add(struct dentry *dentry, aufs_bindex_t bindex,
+	       struct dentry *h_parent, int isdir)
+{
+	int err;
+	umode_t h_mode;
+	struct dentry *h_dentry;
+	struct inode *h_inode;
+
+	h_dentry = au_h_dptr(dentry, bindex);
+	h_inode = h_dentry->d_inode;
+	if (!dentry->d_inode) {
+		err = -EEXIST;
+		if (unlikely(h_inode))
+			goto out;
+	} else {
+		/* rename(2) case */
+		err = -EIO;
+		if (unlikely(!h_inode || !h_inode->i_nlink))
+			goto out;
+
+		h_mode = h_inode->i_mode;
+		if (!isdir) {
+			err = -EISDIR;
+			if (unlikely(S_ISDIR(h_mode)))
+				goto out;
+		} else if (unlikely(!S_ISDIR(h_mode))) {
+			err = -ENOTDIR;
+			goto out;
+		}
+	}
+
+	err = -EIO;
+	/* expected parent dir is locked */
+	if (unlikely(h_parent != h_dentry->d_parent))
+		goto out;
+	err = 0;
+
+ out:
+	return err;
+}
+
+/*
+ * initial procedure of adding a new entry.
+ * prepare writable branch and the parent dir, lock it,
+ * and lookup whiteout for the new entry.
+ */
+static struct dentry*
+lock_hdir_lkup_wh(struct dentry *dentry, struct au_dtime *dt,
+		  struct dentry *src_dentry, struct au_pin *pin,
+		  struct au_wr_dir_args *wr_dir_args)
+{
+	struct dentry *wh_dentry, *h_parent;
+	struct super_block *sb;
+	struct au_branch *br;
+	int err;
+	unsigned int udba;
+	aufs_bindex_t bcpup;
+
+	err = au_wr_dir(dentry, src_dentry, wr_dir_args);
+	bcpup = err;
+	wh_dentry = ERR_PTR(err);
+	if (unlikely(err < 0))
+		goto out;
+
+	sb = dentry->d_sb;
+	udba = au_opt_udba(sb);
+	err = au_pin(pin, dentry, bcpup, udba,
+		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
+	wh_dentry = ERR_PTR(err);
+	if (unlikely(err))
+		goto out;
+
+	h_parent = au_pinned_h_parent(pin);
+	if (udba != AuOpt_UDBA_NONE
+	    && au_dbstart(dentry) == bcpup) {
+		err = au_may_add(dentry, bcpup, h_parent,
+				 au_ftest_wrdir(wr_dir_args->flags, ISDIR));
+		wh_dentry = ERR_PTR(err);
+		if (unlikely(err))
+			goto out_unpin;
+	}
+
+	br = au_sbr(sb, bcpup);
+	if (dt) {
+		struct path tmp = {
+			.dentry	= h_parent,
+			.mnt	= br->br_mnt
+		};
+		au_dtime_store(dt, au_pinned_parent(pin), &tmp);
+	}
+
+	wh_dentry = NULL;
+	if (bcpup != au_dbwh(dentry))
+		goto out; /* success */
+
+	wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, br);
+
+ out_unpin:
+	if (IS_ERR(wh_dentry))
+		au_unpin(pin);
+ out:
+	return wh_dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+enum { Mknod, Symlink, Creat };
+struct simple_arg {
+	int type;
+	union {
+		struct {
+			int mode;
+			struct nameidata *nd;
+		} c;
+		struct {
+			const char *symname;
+		} s;
+		struct {
+			int mode;
+			dev_t dev;
+		} m;
+	} u;
+};
+
+static int add_simple(struct inode *dir, struct dentry *dentry,
+		      struct simple_arg *arg)
+{
+	int err;
+	aufs_bindex_t bstart;
+	unsigned char created;
+	struct au_dtime dt;
+	struct au_pin pin;
+	struct path h_path;
+	struct dentry *wh_dentry, *parent;
+	struct inode *h_dir;
+	struct au_wr_dir_args wr_dir_args = {
+		.force_btgt	= -1,
+		.flags		= AuWrDir_ADD_ENTRY
+	};
+
+	IMustLock(dir);
+
+	parent = dentry->d_parent; /* dir inode is locked */
+	aufs_read_lock(dentry, AuLock_DW);
+	di_write_lock_parent(parent);
+	wh_dentry = lock_hdir_lkup_wh(dentry, &dt, /*src_dentry*/NULL, &pin,
+				      &wr_dir_args);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry))
+		goto out;
+
+	bstart = au_dbstart(dentry);
+	h_path.dentry = au_h_dptr(dentry, bstart);
+	h_path.mnt = au_sbr_mnt(dentry->d_sb, bstart);
+	h_dir = au_pinned_h_dir(&pin);
+	switch (arg->type) {
+	case Creat:
+		err = vfsub_create(h_dir, &h_path, arg->u.c.mode);
+		break;
+	case Symlink:
+		err = vfsub_symlink(h_dir, &h_path, arg->u.s.symname);
+		break;
+	case Mknod:
+		err = vfsub_mknod(h_dir, &h_path, arg->u.m.mode, arg->u.m.dev);
+		break;
+	default:
+		BUG();
+	}
+	created = !err;
+	if (!err)
+		err = epilog(dir, bstart, wh_dentry, dentry);
+
+	/* revert */
+	if (unlikely(created && err && h_path.dentry->d_inode)) {
+		int rerr;
+		rerr = vfsub_unlink(h_dir, &h_path, /*force*/0);
+		if (rerr) {
+			AuIOErr("%.*s revert failure(%d, %d)\n",
+				AuDLNPair(dentry), err, rerr);
+			err = -EIO;
+		}
+		au_dtime_revert(&dt);
+		d_drop(dentry);
+	}
+
+	au_unpin(&pin);
+	dput(wh_dentry);
+
+ out:
+	if (unlikely(err)) {
+		au_update_dbstart(dentry);
+		d_drop(dentry);
+	}
+	di_write_unlock(parent);
+	aufs_read_unlock(dentry, AuLock_DW);
+	return err;
+}
+
+int aufs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
+{
+	struct simple_arg arg = {
+		.type = Mknod,
+		.u.m = {
+			.mode	= mode,
+			.dev	= dev
+		}
+	};
+	return add_simple(dir, dentry, &arg);
+}
+
+int aufs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
+{
+	struct simple_arg arg = {
+		.type = Symlink,
+		.u.s.symname = symname
+	};
+	return add_simple(dir, dentry, &arg);
+}
+
+int aufs_create(struct inode *dir, struct dentry *dentry, int mode,
+		struct nameidata *nd)
+{
+	struct simple_arg arg = {
+		.type = Creat,
+		.u.c = {
+			.mode	= mode,
+			.nd	= nd
+		}
+	};
+	return add_simple(dir, dentry, &arg);
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_link_args {
+	aufs_bindex_t bdst, bsrc;
+	struct au_pin pin;
+	struct path h_path;
+	struct dentry *src_parent, *parent;
+};
+
+static int au_cpup_before_link(struct dentry *src_dentry,
+			       struct au_link_args *a)
+{
+	int err;
+	struct dentry *h_src_dentry;
+	struct mutex *h_mtx;
+
+	di_read_lock_parent(a->src_parent, AuLock_IR);
+	err = au_test_and_cpup_dirs(src_dentry, a->bdst);
+	if (unlikely(err))
+		goto out;
+
+	h_src_dentry = au_h_dptr(src_dentry, a->bsrc);
+	h_mtx = &h_src_dentry->d_inode->i_mutex;
+	err = au_pin(&a->pin, src_dentry, a->bdst,
+		     au_opt_udba(src_dentry->d_sb),
+		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
+	if (unlikely(err))
+		goto out;
+	mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+	err = au_sio_cpup_simple(src_dentry, a->bdst, -1,
+				 AuCpup_DTIME /* | AuCpup_KEEPLINO */);
+	mutex_unlock(h_mtx);
+	au_unpin(&a->pin);
+
+ out:
+	di_read_unlock(a->src_parent, AuLock_IR);
+	return err;
+}
+
+static int au_cpup_or_link(struct dentry *src_dentry, struct au_link_args *a)
+{
+	int err;
+	unsigned char plink;
+	struct inode *h_inode, *inode;
+	struct dentry *h_src_dentry;
+	struct super_block *sb;
+
+	plink = 0;
+	h_inode = NULL;
+	sb = src_dentry->d_sb;
+	inode = src_dentry->d_inode;
+	if (au_ibstart(inode) <= a->bdst)
+		h_inode = au_h_iptr(inode, a->bdst);
+	if (!h_inode || !h_inode->i_nlink) {
+		/* copyup src_dentry as the name of dentry. */
+		au_set_dbstart(src_dentry, a->bdst);
+		au_set_h_dptr(src_dentry, a->bdst, dget(a->h_path.dentry));
+		h_inode = au_h_dptr(src_dentry, a->bsrc)->d_inode;
+		mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+		err = au_sio_cpup_single(src_dentry, a->bdst, a->bsrc, -1,
+					 AuCpup_KEEPLINO, a->parent);
+		mutex_unlock(&h_inode->i_mutex);
+		au_set_h_dptr(src_dentry, a->bdst, NULL);
+		au_set_dbstart(src_dentry, a->bsrc);
+	} else {
+		/* the inode of src_dentry already exists on a.bdst branch */
+		h_src_dentry = d_find_alias(h_inode);
+		if (!h_src_dentry && au_plink_test(inode)) {
+			plink = 1;
+			h_src_dentry = au_plink_lkup(inode, a->bdst);
+			err = PTR_ERR(h_src_dentry);
+			if (IS_ERR(h_src_dentry))
+				goto out;
+
+			if (unlikely(!h_src_dentry->d_inode)) {
+				dput(h_src_dentry);
+				h_src_dentry = NULL;
+			}
+
+		}
+		if (h_src_dentry) {
+			err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
+					 &a->h_path);
+			dput(h_src_dentry);
+		} else {
+			AuIOErr("no dentry found for hi%lu on b%d\n",
+				h_inode->i_ino, a->bdst);
+			err = -EIO;
+		}
+	}
+
+	if (!err && !plink)
+		au_plink_append(inode, a->bdst, a->h_path.dentry);
+
+out:
+	return err;
+}
+
+int aufs_link(struct dentry *src_dentry, struct inode *dir,
+	      struct dentry *dentry)
+{
+	int err, rerr;
+	struct au_dtime dt;
+	struct au_link_args *a;
+	struct dentry *wh_dentry, *h_src_dentry;
+	struct inode *inode;
+	struct super_block *sb;
+	struct au_wr_dir_args wr_dir_args = {
+		/* .force_btgt	= -1, */
+		.flags		= AuWrDir_ADD_ENTRY
+	};
+
+	IMustLock(dir);
+	inode = src_dentry->d_inode;
+	IMustLock(inode);
+
+	err = -ENOENT;
+	if (unlikely(!inode->i_nlink))
+		goto out;
+
+	err = -ENOMEM;
+	a = kzalloc(sizeof(*a), GFP_NOFS);
+	if (unlikely(!a))
+		goto out;
+
+	a->parent = dentry->d_parent; /* dir inode is locked */
+	aufs_read_and_write_lock2(dentry, src_dentry, /*AuLock_FLUSH*/0);
+	a->src_parent = dget_parent(src_dentry);
+	wr_dir_args.force_btgt = au_dbstart(src_dentry);
+
+	di_write_lock_parent(a->parent);
+	wr_dir_args.force_btgt = au_wbr(dentry, wr_dir_args.force_btgt);
+	wh_dentry = lock_hdir_lkup_wh(dentry, &dt, src_dentry, &a->pin,
+				      &wr_dir_args);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry))
+		goto out_unlock;
+
+	err = 0;
+	sb = dentry->d_sb;
+	a->bdst = au_dbstart(dentry);
+	a->h_path.dentry = au_h_dptr(dentry, a->bdst);
+	a->h_path.mnt = au_sbr_mnt(sb, a->bdst);
+	a->bsrc = au_dbstart(src_dentry);
+	if (au_opt_test(au_mntflags(sb), PLINK)) {
+		if (a->bdst < a->bsrc
+		    /* && h_src_dentry->d_sb != a->h_path.dentry->d_sb */)
+			err = au_cpup_or_link(src_dentry, a);
+		else {
+			h_src_dentry = au_h_dptr(src_dentry, a->bdst);
+			err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
+					 &a->h_path);
+		}
+	} else {
+		/*
+		 * copyup src_dentry to the branch we process,
+		 * and then link(2) to it.
+		 */
+		if (a->bdst < a->bsrc
+		    /* && h_src_dentry->d_sb != a->h_path.dentry->d_sb */) {
+			au_unpin(&a->pin);
+			di_write_unlock(a->parent);
+			err = au_cpup_before_link(src_dentry, a);
+			di_write_lock_parent(a->parent);
+			if (!err)
+				err = au_pin(&a->pin, dentry, a->bdst,
+					     au_opt_udba(sb),
+					     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
+			if (unlikely(err))
+				goto out_wh;
+		}
+		if (!err) {
+			h_src_dentry = au_h_dptr(src_dentry, a->bdst);
+			err = -ENOENT;
+			if (h_src_dentry && h_src_dentry->d_inode)
+				err = vfsub_link(h_src_dentry,
+						 au_pinned_h_dir(&a->pin),
+						 &a->h_path);
+		}
+	}
+	if (unlikely(err))
+		goto out_unpin;
+
+	if (wh_dentry) {
+		a->h_path.dentry = wh_dentry;
+		err = au_wh_unlink_dentry(au_pinned_h_dir(&a->pin), &a->h_path,
+					  dentry);
+		if (unlikely(err))
+			goto out_revert;
+	}
+
+	dir->i_version++;
+	if (au_ibstart(dir) == au_dbstart(dentry))
+		au_cpup_attr_timesizes(dir);
+	inc_nlink(inode);
+	inode->i_ctime = dir->i_ctime;
+	if (!d_unhashed(a->h_path.dentry))
+		d_instantiate(dentry, au_igrab(inode));
+	else
+		/* some filesystem calls d_drop() */
+		d_drop(dentry);
+	goto out_unpin; /* success */
+
+ out_revert:
+	rerr = vfsub_unlink(au_pinned_h_dir(&a->pin), &a->h_path, /*force*/0);
+	if (!rerr)
+		goto out_dt;
+	AuIOErr("%.*s reverting failed(%d, %d)\n",
+		AuDLNPair(dentry), err, rerr);
+	err = -EIO;
+ out_dt:
+	d_drop(dentry);
+	au_dtime_revert(&dt);
+ out_unpin:
+	au_unpin(&a->pin);
+ out_wh:
+	dput(wh_dentry);
+ out_unlock:
+	if (unlikely(err)) {
+		au_update_dbstart(dentry);
+		d_drop(dentry);
+	}
+	di_write_unlock(a->parent);
+	dput(a->src_parent);
+	aufs_read_and_write_unlock2(dentry, src_dentry);
+	kfree(a);
+ out:
+	return err;
+}
+
+int aufs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+	int err, rerr;
+	aufs_bindex_t bindex;
+	unsigned char diropq;
+	struct path h_path;
+	struct dentry *wh_dentry, *parent, *opq_dentry;
+	struct mutex *h_mtx;
+	struct super_block *sb;
+	struct {
+		struct au_pin pin;
+		struct au_dtime dt;
+	} *a; /* reduce the stack usage */
+	struct au_wr_dir_args wr_dir_args = {
+		.force_btgt	= -1,
+		.flags		= AuWrDir_ADD_ENTRY | AuWrDir_ISDIR
+	};
+
+	IMustLock(dir);
+
+	err = -ENOMEM;
+	a = kmalloc(sizeof(*a), GFP_NOFS);
+	if (unlikely(!a))
+		goto out;
+
+	aufs_read_lock(dentry, AuLock_DW);
+	parent = dentry->d_parent; /* dir inode is locked */
+	di_write_lock_parent(parent);
+	wh_dentry = lock_hdir_lkup_wh(dentry, &a->dt, /*src_dentry*/NULL,
+				      &a->pin, &wr_dir_args);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry))
+		goto out_free;
+
+	sb = dentry->d_sb;
+	bindex = au_dbstart(dentry);
+	h_path.dentry = au_h_dptr(dentry, bindex);
+	h_path.mnt = au_sbr_mnt(sb, bindex);
+	err = vfsub_mkdir(au_pinned_h_dir(&a->pin), &h_path, mode);
+	if (unlikely(err))
+		goto out_unlock;
+
+	/* make the dir opaque */
+	diropq = 0;
+	h_mtx = &h_path.dentry->d_inode->i_mutex;
+	if (wh_dentry
+	    || au_opt_test(au_mntflags(sb), ALWAYS_DIROPQ)) {
+		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+		opq_dentry = au_diropq_create(dentry, bindex);
+		mutex_unlock(h_mtx);
+		err = PTR_ERR(opq_dentry);
+		if (IS_ERR(opq_dentry))
+			goto out_dir;
+		dput(opq_dentry);
+		diropq = 1;
+	}
+
+	err = epilog(dir, bindex, wh_dentry, dentry);
+	if (!err) {
+		inc_nlink(dir);
+		goto out_unlock; /* success */
+	}
+
+	/* revert */
+	if (diropq) {
+		AuLabel(revert opq);
+		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+		rerr = au_diropq_remove(dentry, bindex);
+		mutex_unlock(h_mtx);
+		if (rerr) {
+			AuIOErr("%.*s reverting diropq failed(%d, %d)\n",
+				AuDLNPair(dentry), err, rerr);
+			err = -EIO;
+		}
+	}
+
+ out_dir:
+	AuLabel(revert dir);
+	rerr = vfsub_rmdir(au_pinned_h_dir(&a->pin), &h_path);
+	if (rerr) {
+		AuIOErr("%.*s reverting dir failed(%d, %d)\n",
+			AuDLNPair(dentry), err, rerr);
+		err = -EIO;
+	}
+	d_drop(dentry);
+	au_dtime_revert(&a->dt);
+ out_unlock:
+	au_unpin(&a->pin);
+	dput(wh_dentry);
+ out_free:
+	if (unlikely(err)) {
+		au_update_dbstart(dentry);
+		d_drop(dentry);
+	}
+	di_write_unlock(parent);
+	aufs_read_unlock(dentry, AuLock_DW);
+	kfree(a);
+ out:
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/i_op.c linux-2.6.31.4/fs/aufs/i_op.c
--- linux-2.6.31.4.orig/fs/aufs/i_op.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/i_op.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,872 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode operations (except add/del/rename)
+ */
+
+#include <linux/device_cgroup.h>
+#include <linux/fs_stack.h>
+#include <linux/mm.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+static int h_permission(struct inode *h_inode, int mask,
+			struct vfsmount *h_mnt, int brperm)
+{
+	int err;
+	const unsigned char write_mask = !!(mask & (MAY_WRITE | MAY_APPEND));
+
+	err = -EACCES;
+	if ((write_mask && IS_IMMUTABLE(h_inode))
+	    || ((mask & MAY_EXEC)
+		&& S_ISREG(h_inode->i_mode)
+		&& ((h_mnt->mnt_flags & MNT_NOEXEC)
+		    || !(h_inode->i_mode & S_IXUGO))))
+		goto out;
+
+	/*
+	 * - skip the lower fs test in the case of write to ro branch.
+	 * - nfs dir permission write check is optimized, but a policy for
+	 *   link/rename requires a real check.
+	 */
+	if ((write_mask && !au_br_writable(brperm))
+	    || (au_test_nfs(h_inode->i_sb) && S_ISDIR(h_inode->i_mode)
+		&& write_mask && !(mask & MAY_READ))
+	    || !h_inode->i_op->permission) {
+		/* AuLabel(generic_permission); */
+		err = generic_permission(h_inode, mask, NULL);
+	} else {
+		/* AuLabel(h_inode->permission); */
+		err = h_inode->i_op->permission(h_inode, mask);
+		AuTraceErr(err);
+	}
+
+	if (!err)
+		err = devcgroup_inode_permission(h_inode, mask);
+	if (!err)
+		err = security_inode_permission
+			(h_inode, mask & (MAY_READ | MAY_WRITE | MAY_EXEC
+					  | MAY_APPEND));
+
+ out:
+	return err;
+}
+
+static int aufs_permission(struct inode *inode, int mask)
+{
+	int err;
+	aufs_bindex_t bindex, bend;
+	const unsigned char isdir = !!S_ISDIR(inode->i_mode);
+	const unsigned char write_mask = !!(mask & (MAY_WRITE | MAY_APPEND));
+	struct inode *h_inode;
+	struct super_block *sb;
+	struct au_branch *br;
+
+	sb = inode->i_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	ii_read_lock_child(inode);
+
+	if (!isdir || write_mask) {
+		h_inode = au_h_iptr(inode, au_ibstart(inode));
+		AuDebugOn(!h_inode
+			  || ((h_inode->i_mode & S_IFMT)
+			      != (inode->i_mode & S_IFMT)));
+		err = 0;
+		bindex = au_ibstart(inode);
+		br = au_sbr(sb, bindex);
+		err = h_permission(h_inode, mask, br->br_mnt, br->br_perm);
+
+		if (write_mask && !err) {
+			/* test whether the upper writable branch exists */
+			err = -EROFS;
+			for (; bindex >= 0; bindex--)
+				if (!au_br_rdonly(au_sbr(sb, bindex))) {
+					err = 0;
+					break;
+				}
+		}
+		goto out;
+	}
+
+	/* non-write to dir */
+	err = 0;
+	bend = au_ibend(inode);
+	for (bindex = au_ibstart(inode); !err && bindex <= bend; bindex++) {
+		h_inode = au_h_iptr(inode, bindex);
+		if (h_inode) {
+			AuDebugOn(!S_ISDIR(h_inode->i_mode));
+			br = au_sbr(sb, bindex);
+			err = h_permission(h_inode, mask, br->br_mnt,
+					   br->br_perm);
+		}
+	}
+
+ out:
+	ii_read_unlock(inode);
+	si_read_unlock(sb);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct dentry *aufs_lookup(struct inode *dir, struct dentry *dentry,
+				  struct nameidata *nd)
+{
+	struct dentry *ret, *parent;
+	struct inode *inode, *h_inode;
+	struct mutex *mtx;
+	struct super_block *sb;
+	int err, npositive;
+	aufs_bindex_t bstart;
+
+	/* temporary workaround for a bug in NFSD readdir */
+	if (!au_test_nfsd(current))
+		IMustLock(dir);
+	else
+		WARN_ONCE(!mutex_is_locked(&dir->i_mutex),
+			  "a known problem of NFSD readdir since 2.6.28\n");
+
+	sb = dir->i_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_alloc_dinfo(dentry);
+	ret = ERR_PTR(err);
+	if (unlikely(err))
+		goto out;
+
+	parent = dentry->d_parent; /* dir inode is locked */
+	di_read_lock_parent(parent, AuLock_IR);
+	npositive = au_lkup_dentry(dentry, au_dbstart(parent), /*type*/0, nd);
+	di_read_unlock(parent, AuLock_IR);
+	err = npositive;
+	ret = ERR_PTR(err);
+	if (unlikely(err < 0))
+		goto out_unlock;
+
+	inode = NULL;
+	if (npositive) {
+		bstart = au_dbstart(dentry);
+		h_inode = au_h_dptr(dentry, bstart)->d_inode;
+		if (!S_ISDIR(h_inode->i_mode)) {
+			/*
+			 * stop 'race'-ing between hardlinks under different
+			 * parents.
+			 */
+			mtx = &au_sbr(sb, bstart)->br_xino.xi_nondir_mtx;
+			mutex_lock(mtx);
+			inode = au_new_inode(dentry, /*must_new*/0);
+			mutex_unlock(mtx);
+		} else
+			inode = au_new_inode(dentry, /*must_new*/0);
+		ret = (void *)inode;
+	}
+	if (IS_ERR(inode))
+		goto out_unlock;
+
+	ret = d_splice_alias(inode, dentry);
+	if (unlikely(IS_ERR(ret) && inode))
+		ii_write_unlock(inode);
+	au_store_oflag(nd, inode);
+
+ out_unlock:
+	di_write_unlock(dentry);
+ out:
+	si_read_unlock(sb);
+	return ret;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_wr_dir_cpup(struct dentry *dentry, struct dentry *parent,
+			  const unsigned char add_entry, aufs_bindex_t bcpup,
+			  aufs_bindex_t bstart)
+{
+	int err;
+	struct dentry *h_parent;
+	struct inode *h_dir;
+
+	if (add_entry) {
+		au_update_dbstart(dentry);
+		IMustLock(parent->d_inode);
+	} else
+		di_write_lock_parent(parent);
+
+	err = 0;
+	if (!au_h_dptr(parent, bcpup)) {
+		if (bstart < bcpup)
+			err = au_cpdown_dirs(dentry, bcpup);
+		else
+			err = au_cpup_dirs(dentry, bcpup);
+	}
+	if (!err && add_entry) {
+		h_parent = au_h_dptr(parent, bcpup);
+		h_dir = h_parent->d_inode;
+		mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+		err = au_lkup_neg(dentry, bcpup);
+		/* todo: no unlock here */
+		mutex_unlock(&h_dir->i_mutex);
+		if (bstart < bcpup && au_dbstart(dentry) < 0) {
+			au_set_dbstart(dentry, 0);
+			au_update_dbrange(dentry, /*do_put_zero*/0);
+		}
+	}
+
+	if (!add_entry)
+		di_write_unlock(parent);
+	if (!err)
+		err = bcpup; /* success */
+
+	return err;
+}
+
+/*
+ * decide the branch and the parent dir where we will create a new entry.
+ * returns new bindex or an error.
+ * copyup the parent dir if needed.
+ */
+int au_wr_dir(struct dentry *dentry, struct dentry *src_dentry,
+	      struct au_wr_dir_args *args)
+{
+	int err;
+	aufs_bindex_t bcpup, bstart, src_bstart;
+	const unsigned char add_entry = !!au_ftest_wrdir(args->flags,
+							 ADD_ENTRY);
+	struct super_block *sb;
+	struct dentry *parent;
+	struct au_sbinfo *sbinfo;
+
+	sb = dentry->d_sb;
+	sbinfo = au_sbi(sb);
+	parent = dget_parent(dentry);
+	bstart = au_dbstart(dentry);
+	bcpup = bstart;
+	if (args->force_btgt < 0) {
+		if (src_dentry) {
+			src_bstart = au_dbstart(src_dentry);
+			if (src_bstart < bstart)
+				bcpup = src_bstart;
+		} else if (add_entry) {
+			err = AuWbrCreate(sbinfo, dentry,
+					  au_ftest_wrdir(args->flags, ISDIR));
+			bcpup = err;
+		}
+
+		if (bcpup < 0 || au_test_ro(sb, bcpup, dentry->d_inode)) {
+			if (add_entry)
+				err = AuWbrCopyup(sbinfo, dentry);
+			else {
+				if (!IS_ROOT(dentry)) {
+					di_read_lock_parent(parent, !AuLock_IR);
+					err = AuWbrCopyup(sbinfo, dentry);
+					di_read_unlock(parent, !AuLock_IR);
+				} else
+					err = AuWbrCopyup(sbinfo, dentry);
+			}
+			bcpup = err;
+			if (unlikely(err < 0))
+				goto out;
+		}
+	} else {
+		bcpup = args->force_btgt;
+		AuDebugOn(au_test_ro(sb, bcpup, dentry->d_inode));
+	}
+	AuDbg("bstart %d, bcpup %d\n", bstart, bcpup);
+	if (bstart < bcpup)
+		au_update_dbrange(dentry, /*do_put_zero*/1);
+
+	err = bcpup;
+	if (bcpup == bstart)
+		goto out; /* success */
+
+	/* copyup the new parent into the branch we process */
+	err = au_wr_dir_cpup(dentry, parent, add_entry, bcpup, bstart);
+
+ out:
+	dput(parent);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct dentry *au_pinned_h_parent(struct au_pin *pin)
+{
+	if (pin && pin->parent)
+		return au_h_dptr(pin->parent, pin->bindex);
+	return NULL;
+}
+
+void au_unpin(struct au_pin *p)
+{
+	if (au_ftest_pin(p->flags, MNT_WRITE))
+		mnt_drop_write(p->h_mnt);
+	if (!p->hdir)
+		return;
+
+	au_hin_imtx_unlock(p->hdir);
+	if (!au_ftest_pin(p->flags, DI_LOCKED))
+		di_read_unlock(p->parent, AuLock_IR);
+	iput(p->hdir->hi_inode);
+	dput(p->parent);
+	p->parent = NULL;
+	p->hdir = NULL;
+	p->h_mnt = NULL;
+}
+
+int au_do_pin(struct au_pin *p)
+{
+	int err;
+	struct super_block *sb;
+	struct dentry *h_dentry, *h_parent;
+	struct au_branch *br;
+	struct inode *h_dir;
+
+	err = 0;
+	sb = p->dentry->d_sb;
+	br = au_sbr(sb, p->bindex);
+	if (IS_ROOT(p->dentry)) {
+		if (au_ftest_pin(p->flags, MNT_WRITE)) {
+			p->h_mnt = br->br_mnt;
+			err = mnt_want_write(p->h_mnt);
+			if (unlikely(err)) {
+				au_fclr_pin(p->flags, MNT_WRITE);
+				goto out_err;
+			}
+		}
+		goto out;
+	}
+
+	h_dentry = NULL;
+	if (p->bindex <= au_dbend(p->dentry))
+		h_dentry = au_h_dptr(p->dentry, p->bindex);
+
+	p->parent = dget_parent(p->dentry);
+	if (!au_ftest_pin(p->flags, DI_LOCKED))
+		di_read_lock(p->parent, AuLock_IR, p->lsc_di);
+
+	h_dir = NULL;
+	h_parent = au_h_dptr(p->parent, p->bindex);
+	p->hdir = au_hi(p->parent->d_inode, p->bindex);
+	if (p->hdir)
+		h_dir = p->hdir->hi_inode;
+
+	/* udba case */
+	if (unlikely(!p->hdir || !h_dir)) {
+		if (!au_ftest_pin(p->flags, DI_LOCKED))
+			di_read_unlock(p->parent, AuLock_IR);
+		dput(p->parent);
+		p->parent = NULL;
+		goto out_err;
+	}
+
+	au_igrab(h_dir);
+	au_hin_imtx_lock_nested(p->hdir, p->lsc_hi);
+
+	if (unlikely(p->hdir->hi_inode != h_parent->d_inode)) {
+		err = -EBUSY;
+		goto out_unpin;
+	}
+	if (h_dentry) {
+		err = au_h_verify(h_dentry, p->udba, h_dir, h_parent, br);
+		if (unlikely(err)) {
+			au_fclr_pin(p->flags, MNT_WRITE);
+			goto out_unpin;
+		}
+	}
+
+	if (au_ftest_pin(p->flags, MNT_WRITE)) {
+		p->h_mnt = br->br_mnt;
+		err = mnt_want_write(p->h_mnt);
+		if (unlikely(err)) {
+			au_fclr_pin(p->flags, MNT_WRITE);
+			goto out_unpin;
+		}
+	}
+	goto out; /* success */
+
+ out_unpin:
+	au_unpin(p);
+ out_err:
+	AuErr("err %d\n", err);
+	err = au_busy_or_stale();
+ out:
+	return err;
+}
+
+void au_pin_init(struct au_pin *p, struct dentry *dentry,
+		 aufs_bindex_t bindex, int lsc_di, int lsc_hi,
+		 unsigned int udba, unsigned char flags)
+{
+	p->dentry = dentry;
+	p->udba = udba;
+	p->lsc_di = lsc_di;
+	p->lsc_hi = lsc_hi;
+	p->flags = flags;
+	p->bindex = bindex;
+
+	p->parent = NULL;
+	p->hdir = NULL;
+	p->h_mnt = NULL;
+}
+
+int au_pin(struct au_pin *pin, struct dentry *dentry, aufs_bindex_t bindex,
+	   unsigned int udba, unsigned char flags)
+{
+	au_pin_init(pin, dentry, bindex, AuLsc_DI_PARENT, AuLsc_I_PARENT2,
+		    udba, flags);
+	return au_do_pin(pin);
+}
+
+/* ---------------------------------------------------------------------- */
+
+#define AuIcpup_DID_CPUP	1
+#define au_ftest_icpup(flags, name)	((flags) & AuIcpup_##name)
+#define au_fset_icpup(flags, name)	{ (flags) |= AuIcpup_##name; }
+#define au_fclr_icpup(flags, name)	{ (flags) &= ~AuIcpup_##name; }
+
+struct au_icpup_args {
+	unsigned char flags;
+	unsigned char pin_flags;
+	aufs_bindex_t btgt;
+	struct au_pin pin;
+	struct path h_path;
+	struct inode *h_inode;
+};
+
+static int au_lock_and_icpup(struct dentry *dentry, struct iattr *ia,
+			     struct au_icpup_args *a)
+{
+	int err;
+	unsigned int udba;
+	loff_t sz;
+	aufs_bindex_t bstart;
+	struct dentry *hi_wh, *parent;
+	struct inode *inode;
+	struct au_wr_dir_args wr_dir_args = {
+		.force_btgt	= -1,
+		.flags		= 0
+	};
+
+	di_write_lock_child(dentry);
+	bstart = au_dbstart(dentry);
+	inode = dentry->d_inode;
+	if (S_ISDIR(inode->i_mode))
+		au_fset_wrdir(wr_dir_args.flags, ISDIR);
+	/* plink or hi_wh() case */
+	if (bstart != au_ibstart(inode))
+		wr_dir_args.force_btgt = au_ibstart(inode);
+	err = au_wr_dir(dentry, /*src_dentry*/NULL, &wr_dir_args);
+	if (unlikely(err < 0))
+		goto out_dentry;
+	a->btgt = err;
+	if (err != bstart)
+		au_fset_icpup(a->flags, DID_CPUP);
+
+	err = 0;
+	a->pin_flags = AuPin_MNT_WRITE;
+	parent = NULL;
+	if (!IS_ROOT(dentry)) {
+		au_fset_pin(a->pin_flags, DI_LOCKED);
+		parent = dget_parent(dentry);
+		di_write_lock_parent(parent);
+	}
+
+	udba = au_opt_udba(dentry->d_sb);
+	if (d_unhashed(dentry) || (ia->ia_valid & ATTR_FILE))
+		udba = AuOpt_UDBA_NONE;
+	err = au_pin(&a->pin, dentry, a->btgt, udba, a->pin_flags);
+	if (unlikely(err)) {
+		if (parent) {
+			di_write_unlock(parent);
+			dput(parent);
+		}
+		goto out_dentry;
+	}
+	a->h_path.dentry = au_h_dptr(dentry, bstart);
+	a->h_inode = a->h_path.dentry->d_inode;
+	mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
+	sz = -1;
+	if ((ia->ia_valid & ATTR_SIZE) && ia->ia_size < i_size_read(a->h_inode))
+		sz = ia->ia_size;
+
+	hi_wh = NULL;
+	if (au_ftest_icpup(a->flags, DID_CPUP) && d_unhashed(dentry)) {
+		hi_wh = au_hi_wh(inode, a->btgt);
+		if (!hi_wh) {
+			err = au_sio_cpup_wh(dentry, a->btgt, sz, /*file*/NULL);
+			if (unlikely(err))
+				goto out_unlock;
+			hi_wh = au_hi_wh(inode, a->btgt);
+			/* todo: revalidate hi_wh? */
+		}
+	}
+
+	if (parent) {
+		au_pin_set_parent_lflag(&a->pin, /*lflag*/0);
+		di_downgrade_lock(parent, AuLock_IR);
+		dput(parent);
+	}
+	if (!au_ftest_icpup(a->flags, DID_CPUP))
+		goto out; /* success */
+
+	if (!d_unhashed(dentry)) {
+		err = au_sio_cpup_simple(dentry, a->btgt, sz, AuCpup_DTIME);
+		if (!err)
+			a->h_path.dentry = au_h_dptr(dentry, a->btgt);
+	} else if (!hi_wh)
+		a->h_path.dentry = au_h_dptr(dentry, a->btgt);
+	else
+		a->h_path.dentry = hi_wh; /* do not dget here */
+
+ out_unlock:
+	mutex_unlock(&a->h_inode->i_mutex);
+	a->h_inode = a->h_path.dentry->d_inode;
+	if (!err) {
+		mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
+		goto out; /* success */
+	}
+
+	au_unpin(&a->pin);
+
+ out_dentry:
+	di_write_unlock(dentry);
+ out:
+	return err;
+}
+
+static int aufs_setattr(struct dentry *dentry, struct iattr *ia)
+{
+	int err;
+	struct inode *inode;
+	struct super_block *sb;
+	struct file *file;
+	struct au_icpup_args *a;
+
+	err = -ENOMEM;
+	a = kzalloc(sizeof(*a), GFP_NOFS);
+	if (unlikely(!a))
+		goto out;
+
+	inode = dentry->d_inode;
+	IMustLock(inode);
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+
+	file = NULL;
+	if (ia->ia_valid & ATTR_FILE) {
+		/* currently ftruncate(2) only */
+		file = ia->ia_file;
+		fi_write_lock(file);
+		ia->ia_file = au_h_fptr(file, au_fbstart(file));
+	}
+
+	if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
+		ia->ia_valid &= ~ATTR_MODE;
+
+	err = au_lock_and_icpup(dentry, ia, a);
+	if (unlikely(err < 0))
+		goto out_si;
+	if (au_ftest_icpup(a->flags, DID_CPUP)) {
+		ia->ia_file = NULL;
+		ia->ia_valid &= ~ATTR_FILE;
+	}
+
+	a->h_path.mnt = au_sbr_mnt(sb, a->btgt);
+	if (ia->ia_valid & ATTR_SIZE) {
+		struct file *f;
+
+		if (ia->ia_size < i_size_read(inode)) {
+			/* unmap only */
+			err = vmtruncate(inode, ia->ia_size);
+			if (unlikely(err))
+				goto out_unlock;
+		}
+
+		f = NULL;
+		if (ia->ia_valid & ATTR_FILE)
+			f = ia->ia_file;
+		mutex_unlock(&a->h_inode->i_mutex);
+		err = vfsub_trunc(&a->h_path, ia->ia_size, ia->ia_valid, f);
+		mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
+	} else
+		err = vfsub_notify_change(&a->h_path, ia);
+	if (!err)
+		au_cpup_attr_changeable(inode);
+
+ out_unlock:
+	mutex_unlock(&a->h_inode->i_mutex);
+	au_unpin(&a->pin);
+	di_write_unlock(dentry);
+ out_si:
+	if (file) {
+		fi_write_unlock(file);
+		ia->ia_file = file;
+		ia->ia_valid |= ATTR_FILE;
+	}
+	si_read_unlock(sb);
+	kfree(a);
+ out:
+	return err;
+}
+
+static int au_getattr_lock_reval(struct dentry *dentry, unsigned int sigen)
+{
+	int err;
+	struct inode *inode;
+	struct dentry *parent;
+
+	err = 0;
+	inode = dentry->d_inode;
+	di_write_lock_child(dentry);
+	if (au_digen(dentry) != sigen || au_iigen(inode) != sigen) {
+		parent = dget_parent(dentry);
+		di_read_lock_parent(parent, AuLock_IR);
+		/* returns a number of positive dentries */
+		err = au_refresh_hdentry(dentry, inode->i_mode & S_IFMT);
+		if (err > 0)
+			err = au_refresh_hinode(inode, dentry);
+		di_read_unlock(parent, AuLock_IR);
+		dput(parent);
+		if (unlikely(!err))
+			err = -EIO;
+	}
+	di_downgrade_lock(dentry, AuLock_IR);
+	if (unlikely(err))
+		di_read_unlock(dentry, AuLock_IR);
+
+	return err;
+}
+
+static void au_refresh_iattr(struct inode *inode, struct kstat *st,
+			     unsigned int nlink)
+{
+	inode->i_mode = st->mode;
+	inode->i_uid = st->uid;
+	inode->i_gid = st->gid;
+	inode->i_atime = st->atime;
+	inode->i_mtime = st->mtime;
+	inode->i_ctime = st->ctime;
+
+	au_cpup_attr_nlink(inode, /*force*/0);
+	if (S_ISDIR(inode->i_mode)) {
+		inode->i_nlink -= nlink;
+		inode->i_nlink += st->nlink;
+	}
+
+	spin_lock(&inode->i_lock);
+	inode->i_blocks = st->blocks;
+	i_size_write(inode, st->size);
+	spin_unlock(&inode->i_lock);
+}
+
+static int aufs_getattr(struct vfsmount *mnt __maybe_unused,
+			struct dentry *dentry, struct kstat *st)
+{
+	int err;
+	unsigned int mnt_flags;
+	aufs_bindex_t bindex;
+	unsigned char udba_none, positive;
+	struct super_block *sb, *h_sb;
+	struct inode *inode;
+	struct vfsmount *h_mnt;
+	struct dentry *h_dentry;
+
+	err = 0;
+	sb = dentry->d_sb;
+	inode = dentry->d_inode;
+	si_read_lock(sb, AuLock_FLUSH);
+	mnt_flags = au_mntflags(sb);
+	udba_none = !!au_opt_test(mnt_flags, UDBA_NONE);
+
+	/* support fstat(2) */
+	if (!d_unhashed(dentry) && !udba_none) {
+		unsigned int sigen = au_sigen(sb);
+		if (au_digen(dentry) == sigen && au_iigen(inode) == sigen)
+			di_read_lock_child(dentry, AuLock_IR);
+		else {
+			AuDebugOn(!IS_ROOT(dentry));
+			err = au_getattr_lock_reval(dentry, sigen);
+			if (unlikely(err))
+				goto out;
+		}
+	} else
+		di_read_lock_child(dentry, AuLock_IR);
+
+	bindex = au_ibstart(inode);
+	h_mnt = au_sbr_mnt(sb, bindex);
+	h_sb = h_mnt->mnt_sb;
+	if (!au_test_fs_bad_iattr(h_sb) && udba_none)
+		goto out_fill; /* success */
+
+	h_dentry = NULL;
+	if (au_dbstart(dentry) == bindex)
+		h_dentry = dget(au_h_dptr(dentry, bindex));
+	else if (au_opt_test(mnt_flags, PLINK) && au_plink_test(inode)) {
+		h_dentry = au_plink_lkup(inode, bindex);
+		if (IS_ERR(h_dentry))
+			goto out_fill; /* pretending success */
+	}
+	/* illegally overlapped or something */
+	if (unlikely(!h_dentry))
+		goto out_fill; /* pretending success */
+
+	positive = !!h_dentry->d_inode;
+	if (positive)
+		err = vfs_getattr(h_mnt, h_dentry, st);
+	dput(h_dentry);
+	if (!err) {
+		if (positive)
+			au_refresh_iattr(inode, st, h_dentry->d_inode->i_nlink);
+		goto out_fill; /* success */
+	}
+	goto out_unlock;
+
+ out_fill:
+	generic_fillattr(inode, st);
+ out_unlock:
+	di_read_unlock(dentry, AuLock_IR);
+ out:
+	si_read_unlock(sb);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int h_readlink(struct dentry *dentry, int bindex, char __user *buf,
+		      int bufsiz)
+{
+	int err;
+	struct super_block *sb;
+	struct dentry *h_dentry;
+
+	err = -EINVAL;
+	h_dentry = au_h_dptr(dentry, bindex);
+	if (unlikely(/* !h_dentry
+		     || !h_dentry->d_inode
+		     || !h_dentry->d_inode->i_op
+		     || */ !h_dentry->d_inode->i_op->readlink))
+		goto out;
+
+	err = security_inode_readlink(h_dentry);
+	if (unlikely(err))
+		goto out;
+
+	sb = dentry->d_sb;
+	if (!au_test_ro(sb, bindex, dentry->d_inode)) {
+		vfsub_touch_atime(au_sbr_mnt(sb, bindex), h_dentry);
+		fsstack_copy_attr_atime(dentry->d_inode, h_dentry->d_inode);
+	}
+	err = h_dentry->d_inode->i_op->readlink(h_dentry, buf, bufsiz);
+
+ out:
+	return err;
+}
+
+static int aufs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
+{
+	int err;
+
+	aufs_read_lock(dentry, AuLock_IR);
+	err = h_readlink(dentry, au_dbstart(dentry), buf, bufsiz);
+	aufs_read_unlock(dentry, AuLock_IR);
+
+	return err;
+}
+
+static void *aufs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	int err;
+	char *buf;
+	mm_segment_t old_fs;
+
+	err = -ENOMEM;
+	buf = __getname();
+	if (unlikely(!buf))
+		goto out;
+
+	aufs_read_lock(dentry, AuLock_IR);
+	old_fs = get_fs();
+	set_fs(KERNEL_DS);
+	err = h_readlink(dentry, au_dbstart(dentry), (char __user *)buf,
+			 PATH_MAX);
+	set_fs(old_fs);
+	aufs_read_unlock(dentry, AuLock_IR);
+
+	if (err >= 0) {
+		buf[err] = 0;
+		/* will be freed by put_link */
+		nd_set_link(nd, buf);
+		return NULL; /* success */
+	}
+	__putname(buf);
+
+ out:
+	path_put(&nd->path);
+	AuTraceErr(err);
+	return ERR_PTR(err);
+}
+
+static void aufs_put_link(struct dentry *dentry __maybe_unused,
+			  struct nameidata *nd, void *cookie __maybe_unused)
+{
+	__putname(nd_get_link(nd));
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void aufs_truncate_range(struct inode *inode __maybe_unused,
+				loff_t start __maybe_unused,
+				loff_t end __maybe_unused)
+{
+	AuUnsupport();
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct inode_operations aufs_symlink_iop = {
+	.permission	= aufs_permission,
+	.setattr	= aufs_setattr,
+	.getattr	= aufs_getattr,
+	.readlink	= aufs_readlink,
+	.follow_link	= aufs_follow_link,
+	.put_link	= aufs_put_link
+};
+
+struct inode_operations aufs_dir_iop = {
+	.create		= aufs_create,
+	.lookup		= aufs_lookup,
+	.link		= aufs_link,
+	.unlink		= aufs_unlink,
+	.symlink	= aufs_symlink,
+	.mkdir		= aufs_mkdir,
+	.rmdir		= aufs_rmdir,
+	.mknod		= aufs_mknod,
+	.rename		= aufs_rename,
+
+	.permission	= aufs_permission,
+	.setattr	= aufs_setattr,
+	.getattr	= aufs_getattr
+};
+
+struct inode_operations aufs_iop = {
+	.permission	= aufs_permission,
+	.setattr	= aufs_setattr,
+	.getattr	= aufs_getattr,
+	.truncate_range	= aufs_truncate_range
+};
diff -Nur linux-2.6.31.4.orig/fs/aufs/i_op_del.c linux-2.6.31.4/fs/aufs/i_op_del.c
--- linux-2.6.31.4.orig/fs/aufs/i_op_del.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/i_op_del.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,468 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode operations (del entry)
+ */
+
+#include "aufs.h"
+
+/*
+ * decide if a new whiteout for @dentry is necessary or not.
+ * when it is necessary, prepare the parent dir for the upper branch whose
+ * branch index is @bcpup for creation. the actual creation of the whiteout will
+ * be done by caller.
+ * return value:
+ * 0: wh is unnecessary
+ * plus: wh is necessary
+ * minus: error
+ */
+int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup)
+{
+	int need_wh, err;
+	aufs_bindex_t bstart;
+	struct super_block *sb;
+
+	sb = dentry->d_sb;
+	bstart = au_dbstart(dentry);
+	if (*bcpup < 0) {
+		*bcpup = bstart;
+		if (au_test_ro(sb, bstart, dentry->d_inode)) {
+			err = AuWbrCopyup(au_sbi(sb), dentry);
+			*bcpup = err;
+			if (unlikely(err < 0))
+				goto out;
+		}
+	} else
+		AuDebugOn(bstart < *bcpup
+			  || au_test_ro(sb, *bcpup, dentry->d_inode));
+	AuDbg("bcpup %d, bstart %d\n", *bcpup, bstart);
+
+	if (*bcpup != bstart) {
+		err = au_cpup_dirs(dentry, *bcpup);
+		if (unlikely(err))
+			goto out;
+		need_wh = 1;
+	} else {
+		aufs_bindex_t old_bend, new_bend, bdiropq = -1;
+
+		old_bend = au_dbend(dentry);
+		if (isdir) {
+			bdiropq = au_dbdiropq(dentry);
+			au_set_dbdiropq(dentry, -1);
+		}
+		need_wh = au_lkup_dentry(dentry, bstart + 1, /*type*/0,
+					 /*nd*/NULL);
+		err = need_wh;
+		if (isdir)
+			au_set_dbdiropq(dentry, bdiropq);
+		if (unlikely(err < 0))
+			goto out;
+		new_bend = au_dbend(dentry);
+		if (!need_wh && old_bend != new_bend) {
+			au_set_h_dptr(dentry, new_bend, NULL);
+			au_set_dbend(dentry, old_bend);
+		}
+	}
+	AuDbg("need_wh %d\n", need_wh);
+	err = need_wh;
+
+ out:
+	return err;
+}
+
+/*
+ * simple tests for the del-entry operations.
+ * following the checks in vfs, plus the parent-child relationship.
+ */
+int au_may_del(struct dentry *dentry, aufs_bindex_t bindex,
+	       struct dentry *h_parent, int isdir)
+{
+	int err;
+	umode_t h_mode;
+	struct dentry *h_dentry, *h_latest;
+	struct inode *h_inode;
+
+	h_dentry = au_h_dptr(dentry, bindex);
+	h_inode = h_dentry->d_inode;
+	if (dentry->d_inode) {
+		err = -ENOENT;
+		if (unlikely(!h_inode || !h_inode->i_nlink))
+			goto out;
+
+		h_mode = h_inode->i_mode;
+		if (!isdir) {
+			err = -EISDIR;
+			if (unlikely(S_ISDIR(h_mode)))
+				goto out;
+		} else if (unlikely(!S_ISDIR(h_mode))) {
+			err = -ENOTDIR;
+			goto out;
+		}
+	} else {
+		/* rename(2) case */
+		err = -EIO;
+		if (unlikely(h_inode))
+			goto out;
+	}
+
+	err = -ENOENT;
+	/* expected parent dir is locked */
+	if (unlikely(h_parent != h_dentry->d_parent))
+		goto out;
+	err = 0;
+
+	/*
+	 * rmdir a dir may break the consistency on some filesystem.
+	 * let's try heavy test.
+	 */
+	err = -EACCES;
+	if (unlikely(au_test_h_perm(h_parent->d_inode, MAY_EXEC | MAY_WRITE)))
+		goto out;
+
+	h_latest = au_sio_lkup_one(&dentry->d_name, h_parent,
+				   au_sbr(dentry->d_sb, bindex));
+	err = -EIO;
+	if (IS_ERR(h_latest))
+		goto out;
+	if (h_latest == h_dentry)
+		err = 0;
+	dput(h_latest);
+
+ out:
+	return err;
+}
+
+/*
+ * decide the branch where we operate for @dentry. the branch index will be set
+ * @rbcpup. after diciding it, 'pin' it and store the timestamps of the parent
+ * dir for reverting.
+ * when a new whiteout is necessary, create it.
+ */
+static struct dentry*
+lock_hdir_create_wh(struct dentry *dentry, int isdir, aufs_bindex_t *rbcpup,
+		    struct au_dtime *dt, struct au_pin *pin)
+{
+	struct dentry *wh_dentry;
+	struct super_block *sb;
+	struct path h_path;
+	int err, need_wh;
+	unsigned int udba;
+	aufs_bindex_t bcpup;
+
+	need_wh = au_wr_dir_need_wh(dentry, isdir, rbcpup);
+	wh_dentry = ERR_PTR(need_wh);
+	if (unlikely(need_wh < 0))
+		goto out;
+
+	sb = dentry->d_sb;
+	udba = au_opt_udba(sb);
+	bcpup = *rbcpup;
+	err = au_pin(pin, dentry, bcpup, udba,
+		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
+	wh_dentry = ERR_PTR(err);
+	if (unlikely(err))
+		goto out;
+
+	h_path.dentry = au_pinned_h_parent(pin);
+	if (udba != AuOpt_UDBA_NONE
+	    && au_dbstart(dentry) == bcpup) {
+		err = au_may_del(dentry, bcpup, h_path.dentry, isdir);
+		wh_dentry = ERR_PTR(err);
+		if (unlikely(err))
+			goto out_unpin;
+	}
+
+	h_path.mnt = au_sbr_mnt(sb, bcpup);
+	au_dtime_store(dt, au_pinned_parent(pin), &h_path);
+	wh_dentry = NULL;
+	if (!need_wh)
+		goto out; /* success, no need to create whiteout */
+
+	wh_dentry = au_wh_create(dentry, bcpup, h_path.dentry);
+	if (!IS_ERR(wh_dentry))
+		goto out; /* success */
+	/* returns with the parent is locked and wh_dentry is dget-ed */
+
+ out_unpin:
+	au_unpin(pin);
+ out:
+	return wh_dentry;
+}
+
+/*
+ * when removing a dir, rename it to a unique temporary whiteout-ed name first
+ * in order to be revertible and save time for removing many child whiteouts
+ * under the dir.
+ * returns 1 when there are too many child whiteout and caller should remove
+ * them asynchronously. returns 0 when the number of children is enough small to
+ * remove now or the branch fs is a remote fs.
+ * otherwise return an error.
+ */
+static int renwh_and_rmdir(struct dentry *dentry, aufs_bindex_t bindex,
+			   struct au_nhash *whlist, struct inode *dir)
+{
+	int rmdir_later, err, dirwh;
+	struct dentry *h_dentry;
+	struct super_block *sb;
+
+	sb = dentry->d_sb;
+	SiMustAnyLock(sb);
+	h_dentry = au_h_dptr(dentry, bindex);
+	err = au_whtmp_ren(h_dentry, au_sbr(sb, bindex));
+	if (unlikely(err))
+		goto out;
+
+	/* stop monitoring */
+	au_hin_free(au_hi(dentry->d_inode, bindex));
+
+	if (!au_test_fs_remote(h_dentry->d_sb)) {
+		dirwh = au_sbi(sb)->si_dirwh;
+		rmdir_later = (dirwh <= 1);
+		if (!rmdir_later)
+			rmdir_later = au_nhash_test_longer_wh(whlist, bindex,
+							      dirwh);
+		if (rmdir_later)
+			return rmdir_later;
+	}
+
+	err = au_whtmp_rmdir(dir, bindex, h_dentry, whlist);
+	if (unlikely(err)) {
+		AuIOErr("rmdir %.*s, b%d failed, %d. ignored\n",
+			AuDLNPair(h_dentry), bindex, err);
+		err = 0;
+	}
+
+ out:
+	return err;
+}
+
+/*
+ * final procedure for deleting a entry.
+ * maintain dentry and iattr.
+ */
+static void epilog(struct inode *dir, struct dentry *dentry,
+		   aufs_bindex_t bindex)
+{
+	struct inode *inode;
+
+	inode = dentry->d_inode;
+	d_drop(dentry);
+	inode->i_ctime = dir->i_ctime;
+
+	if (atomic_read(&dentry->d_count) == 1) {
+		au_set_h_dptr(dentry, au_dbstart(dentry), NULL);
+		au_update_dbstart(dentry);
+	}
+	if (au_ibstart(dir) == bindex)
+		au_cpup_attr_timesizes(dir);
+	dir->i_version++;
+}
+
+/*
+ * when an error happened, remove the created whiteout and revert everything.
+ */
+static int do_revert(int err, struct inode *dir, aufs_bindex_t bwh,
+		     struct dentry *wh_dentry, struct dentry *dentry,
+		     struct au_dtime *dt)
+{
+	int rerr;
+	struct path h_path = {
+		.dentry	= wh_dentry,
+		.mnt	= au_sbr_mnt(dir->i_sb, bwh)
+	};
+
+	rerr = au_wh_unlink_dentry(au_h_iptr(dir, bwh), &h_path, dentry);
+	if (!rerr) {
+		au_set_dbwh(dentry, bwh);
+		au_dtime_revert(dt);
+		return 0;
+	}
+
+	AuIOErr("%.*s reverting whiteout failed(%d, %d)\n",
+		AuDLNPair(dentry), err, rerr);
+	return -EIO;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int aufs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	int err;
+	aufs_bindex_t bwh, bindex, bstart;
+	struct au_dtime dt;
+	struct au_pin pin;
+	struct path h_path;
+	struct inode *inode, *h_dir;
+	struct dentry *parent, *wh_dentry;
+
+	IMustLock(dir);
+	inode = dentry->d_inode;
+	if (unlikely(!inode))
+		return -ENOENT; /* possible? */
+	IMustLock(inode);
+
+	aufs_read_lock(dentry, AuLock_DW);
+	parent = dentry->d_parent; /* dir inode is locked */
+	di_write_lock_parent(parent);
+
+	bstart = au_dbstart(dentry);
+	bwh = au_dbwh(dentry);
+	bindex = -1;
+	wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/0, &bindex, &dt, &pin);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry))
+		goto out;
+
+	h_path.mnt = au_sbr_mnt(dentry->d_sb, bstart);
+	h_path.dentry = au_h_dptr(dentry, bstart);
+	dget(h_path.dentry);
+	if (bindex == bstart) {
+		h_dir = au_pinned_h_dir(&pin);
+		err = vfsub_unlink(h_dir, &h_path, /*force*/0);
+	} else {
+		/* dir inode is locked */
+		h_dir = wh_dentry->d_parent->d_inode;
+		IMustLock(h_dir);
+		err = 0;
+	}
+
+	if (!err) {
+		drop_nlink(inode);
+		epilog(dir, dentry, bindex);
+
+		/* update target timestamps */
+		if (bindex == bstart) {
+			vfsub_update_h_iattr(&h_path, /*did*/NULL); /*ignore*/
+			inode->i_ctime = h_path.dentry->d_inode->i_ctime;
+		} else
+			/* todo: this timestamp may be reverted later */
+			inode->i_ctime = h_dir->i_ctime;
+		goto out_unlock; /* success */
+	}
+
+	/* revert */
+	if (wh_dentry) {
+		int rerr;
+
+		rerr = do_revert(err, dir, bwh, wh_dentry, dentry, &dt);
+		if (rerr)
+			err = rerr;
+	}
+
+ out_unlock:
+	au_unpin(&pin);
+	dput(wh_dentry);
+	dput(h_path.dentry);
+ out:
+	di_write_unlock(parent);
+	aufs_read_unlock(dentry, AuLock_DW);
+	return err;
+}
+
+int aufs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	int err, rmdir_later;
+	aufs_bindex_t bwh, bindex, bstart;
+	struct au_dtime dt;
+	struct au_pin pin;
+	struct inode *inode;
+	struct dentry *parent, *wh_dentry, *h_dentry;
+	struct au_whtmp_rmdir *args;
+
+	IMustLock(dir);
+	inode = dentry->d_inode;
+	err = -ENOENT; /* possible? */
+	if (unlikely(!inode))
+		goto out;
+	IMustLock(inode);
+
+	aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH);
+	err = -ENOMEM;
+	args = au_whtmp_rmdir_alloc(dir->i_sb, GFP_NOFS);
+	if (unlikely(!args))
+		goto out_unlock;
+
+	parent = dentry->d_parent; /* dir inode is locked */
+	di_write_lock_parent(parent);
+	err = au_test_empty(dentry, &args->whlist);
+	if (unlikely(err))
+		goto out_args;
+
+	bstart = au_dbstart(dentry);
+	bwh = au_dbwh(dentry);
+	bindex = -1;
+	wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/1, &bindex, &dt, &pin);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry))
+		goto out_args;
+
+	h_dentry = au_h_dptr(dentry, bstart);
+	dget(h_dentry);
+	rmdir_later = 0;
+	if (bindex == bstart) {
+		err = renwh_and_rmdir(dentry, bstart, &args->whlist, dir);
+		if (err > 0) {
+			rmdir_later = err;
+			err = 0;
+		}
+	} else {
+		/* stop monitoring */
+		au_hin_free(au_hi(inode, bstart));
+
+		/* dir inode is locked */
+		IMustLock(wh_dentry->d_parent->d_inode);
+		err = 0;
+	}
+
+	if (!err) {
+		clear_nlink(inode);
+		au_set_dbdiropq(dentry, -1);
+		epilog(dir, dentry, bindex);
+
+		if (rmdir_later) {
+			au_whtmp_kick_rmdir(dir, bstart, h_dentry, args);
+			args = NULL;
+		}
+
+		goto out_unpin; /* success */
+	}
+
+	/* revert */
+	AuLabel(revert);
+	if (wh_dentry) {
+		int rerr;
+
+		rerr = do_revert(err, dir, bwh, wh_dentry, dentry, &dt);
+		if (rerr)
+			err = rerr;
+	}
+
+ out_unpin:
+	au_unpin(&pin);
+	dput(wh_dentry);
+	dput(h_dentry);
+ out_args:
+	di_write_unlock(parent);
+	if (args)
+		au_whtmp_rmdir_free(args);
+ out_unlock:
+	aufs_read_unlock(dentry, AuLock_DW);
+ out:
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/i_op_ren.c linux-2.6.31.4/fs/aufs/i_op_ren.c
--- linux-2.6.31.4.orig/fs/aufs/i_op_ren.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/i_op_ren.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,948 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode operation (rename entry)
+ * todo: this is crazy monster
+ */
+
+#include "aufs.h"
+
+enum { AuSRC, AuDST, AuSrcDst };
+enum { AuPARENT, AuCHILD, AuParentChild };
+
+#define AuRen_ISDIR	1
+#define AuRen_ISSAMEDIR	(1 << 1)
+#define AuRen_WHSRC	(1 << 2)
+#define AuRen_WHDST	(1 << 3)
+#define AuRen_MNT_WRITE	(1 << 4)
+#define AuRen_DT_DSTDIR	(1 << 5)
+#define AuRen_DIROPQ	(1 << 6)
+#define AuRen_CPUP	(1 << 7)
+#define au_ftest_ren(flags, name)	((flags) & AuRen_##name)
+#define au_fset_ren(flags, name)	{ (flags) |= AuRen_##name; }
+#define au_fclr_ren(flags, name)	{ (flags) &= ~AuRen_##name; }
+
+struct au_ren_args {
+	struct {
+		struct dentry *dentry, *h_dentry, *parent, *h_parent,
+			*wh_dentry;
+		struct inode *dir, *inode;
+		struct au_hinode *hdir;
+		struct au_dtime dt[AuParentChild];
+		aufs_bindex_t bstart;
+	} sd[AuSrcDst];
+
+#define src_dentry	sd[AuSRC].dentry
+#define src_dir		sd[AuSRC].dir
+#define src_inode	sd[AuSRC].inode
+#define src_h_dentry	sd[AuSRC].h_dentry
+#define src_parent	sd[AuSRC].parent
+#define src_h_parent	sd[AuSRC].h_parent
+#define src_wh_dentry	sd[AuSRC].wh_dentry
+#define src_hdir	sd[AuSRC].hdir
+#define src_h_dir	sd[AuSRC].hdir->hi_inode
+#define src_dt		sd[AuSRC].dt
+#define src_bstart	sd[AuSRC].bstart
+
+#define dst_dentry	sd[AuDST].dentry
+#define dst_dir		sd[AuDST].dir
+#define dst_inode	sd[AuDST].inode
+#define dst_h_dentry	sd[AuDST].h_dentry
+#define dst_parent	sd[AuDST].parent
+#define dst_h_parent	sd[AuDST].h_parent
+#define dst_wh_dentry	sd[AuDST].wh_dentry
+#define dst_hdir	sd[AuDST].hdir
+#define dst_h_dir	sd[AuDST].hdir->hi_inode
+#define dst_dt		sd[AuDST].dt
+#define dst_bstart	sd[AuDST].bstart
+
+	struct dentry *h_trap;
+	struct au_branch *br;
+	struct au_hinode *src_hinode;
+	struct path h_path;
+	struct au_nhash whlist;
+	aufs_bindex_t btgt;
+
+	unsigned int flags;
+
+	struct au_whtmp_rmdir *thargs;
+	struct dentry *h_dst;
+};
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * functions for reverting.
+ * when an error happened in a single rename systemcall, we should revert
+ * everything as if nothing happend.
+ * we don't need to revert the copied-up/down the parent dir since they are
+ * harmless.
+ */
+
+#define RevertFailure(fmt, args...) do { \
+	AuIOErr("revert failure: " fmt " (%d, %d)\n", \
+		##args, err, rerr); \
+	err = -EIO; \
+} while (0)
+
+static void au_ren_rev_diropq(int err, struct au_ren_args *a)
+{
+	int rerr;
+
+	au_hin_imtx_lock_nested(a->src_hinode, AuLsc_I_CHILD);
+	rerr = au_diropq_remove(a->src_dentry, a->btgt);
+	au_hin_imtx_unlock(a->src_hinode);
+	if (rerr)
+		RevertFailure("remove diropq %.*s", AuDLNPair(a->src_dentry));
+}
+
+
+static void au_ren_rev_rename(int err, struct au_ren_args *a)
+{
+	int rerr;
+
+	a->h_path.dentry = au_lkup_one(&a->src_dentry->d_name, a->src_h_parent,
+				       a->br, /*nd*/NULL);
+	rerr = PTR_ERR(a->h_path.dentry);
+	if (IS_ERR(a->h_path.dentry)) {
+		RevertFailure("au_lkup_one %.*s", AuDLNPair(a->src_dentry));
+		return;
+	}
+
+	rerr = vfsub_rename(a->dst_h_dir,
+			    au_h_dptr(a->src_dentry, a->btgt),
+			    a->src_h_dir, &a->h_path);
+	d_drop(a->h_path.dentry);
+	dput(a->h_path.dentry);
+	/* au_set_h_dptr(a->src_dentry, a->btgt, NULL); */
+	if (rerr)
+		RevertFailure("rename %.*s", AuDLNPair(a->src_dentry));
+}
+
+static void au_ren_rev_cpup(int err, struct au_ren_args *a)
+{
+	int rerr;
+
+	a->h_path.dentry = a->dst_h_dentry;
+	rerr = vfsub_unlink(a->dst_h_dir, &a->h_path, /*force*/0);
+	au_set_h_dptr(a->src_dentry, a->btgt, NULL);
+	au_set_dbstart(a->src_dentry, a->src_bstart);
+	if (rerr)
+		RevertFailure("unlink %.*s", AuDLNPair(a->dst_h_dentry));
+}
+
+
+static void au_ren_rev_whtmp(int err, struct au_ren_args *a)
+{
+	int rerr;
+
+	a->h_path.dentry = au_lkup_one(&a->dst_dentry->d_name, a->dst_h_parent,
+				       a->br, /*nd*/NULL);
+	rerr = PTR_ERR(a->h_path.dentry);
+	if (IS_ERR(a->h_path.dentry)) {
+		RevertFailure("lookup %.*s", AuDLNPair(a->dst_dentry));
+		return;
+	}
+	if (a->h_path.dentry->d_inode) {
+		d_drop(a->h_path.dentry);
+		dput(a->h_path.dentry);
+		return;
+	}
+
+	rerr = vfsub_rename(a->dst_h_dir, a->h_dst, a->dst_h_dir, &a->h_path);
+	d_drop(a->h_path.dentry);
+	dput(a->h_path.dentry);
+	if (!rerr) {
+		au_set_h_dptr(a->dst_dentry, a->btgt, NULL);
+		au_set_h_dptr(a->dst_dentry, a->btgt, dget(a->h_dst));
+	} else
+		RevertFailure("rename %.*s", AuDLNPair(a->h_dst));
+}
+
+static void au_ren_rev_whsrc(int err, struct au_ren_args *a)
+{
+	int rerr;
+
+	a->h_path.dentry = a->src_wh_dentry;
+	rerr = au_wh_unlink_dentry(a->src_h_dir, &a->h_path, a->src_dentry);
+	if (rerr)
+		RevertFailure("unlink %.*s", AuDLNPair(a->src_wh_dentry));
+}
+
+static void au_ren_rev_drop(struct au_ren_args *a)
+{
+	struct dentry *d, *h_d;
+	int i;
+	aufs_bindex_t bend, bindex;
+
+	for (i = 0; i < AuSrcDst; i++) {
+		d = a->sd[i].dentry;
+		d_drop(d);
+		bend = au_dbend(d);
+		for (bindex = au_dbstart(d); bindex <= bend; bindex++) {
+			h_d = au_h_dptr(d, bindex);
+			if (h_d)
+				d_drop(h_d);
+		}
+	}
+
+	au_update_dbstart(a->dst_dentry);
+	if (a->thargs)
+		d_drop(a->h_dst);
+}
+#undef RevertFailure
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * when we have to copyup the renaming entry, do it with the rename-target name
+ * in order to minimize the cost (the later actual rename is unnecessary).
+ * otherwise rename it on the target branch.
+ */
+static int au_ren_or_cpup(struct au_ren_args *a)
+{
+	int err;
+	struct dentry *d;
+
+	d = a->src_dentry;
+	if (au_dbstart(d) == a->btgt) {
+		a->h_path.dentry = a->dst_h_dentry;
+		if (au_ftest_ren(a->flags, DIROPQ)
+		    && au_dbdiropq(d) == a->btgt)
+			au_fclr_ren(a->flags, DIROPQ);
+		AuDebugOn(au_dbstart(d) != a->btgt);
+		err = vfsub_rename(a->src_h_dir, au_h_dptr(d, a->btgt),
+				   a->dst_h_dir, &a->h_path);
+	} else {
+		struct mutex *h_mtx = &a->src_h_dentry->d_inode->i_mutex;
+
+		au_fset_ren(a->flags, CPUP);
+		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+		au_set_dbstart(d, a->btgt);
+		au_set_h_dptr(d, a->btgt, dget(a->dst_h_dentry));
+		err = au_sio_cpup_single(d, a->btgt, a->src_bstart, -1,
+					 !AuCpup_DTIME, a->dst_parent);
+		if (unlikely(err)) {
+			au_set_h_dptr(d, a->btgt, NULL);
+			au_set_dbstart(d, a->src_bstart);
+		}
+		mutex_unlock(h_mtx);
+	}
+
+	return err;
+}
+
+/* cf. aufs_rmdir() */
+static int au_ren_del_whtmp(struct au_ren_args *a)
+{
+	int err;
+	struct inode *dir;
+
+	dir = a->dst_dir;
+	SiMustAnyLock(dir->i_sb);
+	if (!au_nhash_test_longer_wh(&a->whlist, a->btgt,
+				     au_sbi(dir->i_sb)->si_dirwh)
+	    || au_test_fs_remote(a->h_dst->d_sb)) {
+		err = au_whtmp_rmdir(dir, a->btgt, a->h_dst, &a->whlist);
+		if (unlikely(err))
+			AuWarn("failed removing whtmp dir %.*s (%d), "
+			       "ignored.\n", AuDLNPair(a->h_dst), err);
+	} else {
+		au_nhash_wh_free(&a->thargs->whlist);
+		a->thargs->whlist = a->whlist;
+		a->whlist.nh_num = 0;
+		au_whtmp_kick_rmdir(dir, a->btgt, a->h_dst, a->thargs);
+		dput(a->h_dst);
+		a->thargs = NULL;
+	}
+
+	return 0;
+}
+
+/* make it 'opaque' dir. */
+static int au_ren_diropq(struct au_ren_args *a)
+{
+	int err;
+	struct dentry *diropq;
+
+	err = 0;
+	a->src_hinode = au_hi(a->src_inode, a->btgt);
+	au_hin_imtx_lock_nested(a->src_hinode, AuLsc_I_CHILD);
+	diropq = au_diropq_create(a->src_dentry, a->btgt);
+	au_hin_imtx_unlock(a->src_hinode);
+	if (IS_ERR(diropq))
+		err = PTR_ERR(diropq);
+	dput(diropq);
+
+	return err;
+}
+
+static int do_rename(struct au_ren_args *a)
+{
+	int err;
+	struct dentry *d, *h_d;
+
+	/* prepare workqueue args for asynchronous rmdir */
+	h_d = a->dst_h_dentry;
+	if (au_ftest_ren(a->flags, ISDIR) && h_d->d_inode) {
+		err = -ENOMEM;
+		a->thargs = au_whtmp_rmdir_alloc(a->src_dentry->d_sb, GFP_NOFS);
+		if (unlikely(!a->thargs))
+			goto out;
+		a->h_dst = dget(h_d);
+	}
+
+	/* create whiteout for src_dentry */
+	if (au_ftest_ren(a->flags, WHSRC)) {
+		a->src_wh_dentry
+			= au_wh_create(a->src_dentry, a->btgt, a->src_h_parent);
+		err = PTR_ERR(a->src_wh_dentry);
+		if (IS_ERR(a->src_wh_dentry))
+			goto out_thargs;
+	}
+
+	/* lookup whiteout for dentry */
+	if (au_ftest_ren(a->flags, WHDST)) {
+		h_d = au_wh_lkup(a->dst_h_parent, &a->dst_dentry->d_name,
+				 a->br);
+		err = PTR_ERR(h_d);
+		if (IS_ERR(h_d))
+			goto out_whsrc;
+		if (!h_d->d_inode)
+			dput(h_d);
+		else
+			a->dst_wh_dentry = h_d;
+	}
+
+	/* rename dentry to tmpwh */
+	if (a->thargs) {
+		err = au_whtmp_ren(a->dst_h_dentry, a->br);
+		if (unlikely(err))
+			goto out_whdst;
+
+		d = a->dst_dentry;
+		au_set_h_dptr(d, a->btgt, NULL);
+		err = au_lkup_neg(d, a->btgt);
+		if (unlikely(err))
+			goto out_whtmp;
+		a->dst_h_dentry = au_h_dptr(d, a->btgt);
+	}
+
+	/* cpup src */
+	if (a->dst_h_dentry->d_inode && a->src_bstart != a->btgt) {
+		struct mutex *h_mtx = &a->src_h_dentry->d_inode->i_mutex;
+
+		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+		err = au_sio_cpup_simple(a->src_dentry, a->btgt, -1,
+					 !AuCpup_DTIME);
+		mutex_unlock(h_mtx);
+		if (unlikely(err))
+			goto out_whtmp;
+	}
+
+	/* rename by vfs_rename or cpup */
+	d = a->dst_dentry;
+	if (au_ftest_ren(a->flags, ISDIR)
+	    && (a->dst_wh_dentry
+		|| au_dbdiropq(d) == a->btgt
+		/* hide the lower to keep xino */
+		|| a->btgt < au_dbend(d)
+		|| au_opt_test(au_mntflags(d->d_sb), ALWAYS_DIROPQ)))
+		au_fset_ren(a->flags, DIROPQ);
+	err = au_ren_or_cpup(a);
+	if (unlikely(err))
+		/* leave the copied-up one */
+		goto out_whtmp;
+
+	/* make dir opaque */
+	if (au_ftest_ren(a->flags, DIROPQ)) {
+		err = au_ren_diropq(a);
+		if (unlikely(err))
+			goto out_rename;
+	}
+
+	/* update target timestamps */
+	AuDebugOn(au_dbstart(a->src_dentry) != a->btgt);
+	a->h_path.dentry = au_h_dptr(a->src_dentry, a->btgt);
+	vfsub_update_h_iattr(&a->h_path, /*did*/NULL); /*ignore*/
+	a->src_inode->i_ctime = a->h_path.dentry->d_inode->i_ctime;
+
+	/* remove whiteout for dentry */
+	if (a->dst_wh_dentry) {
+		a->h_path.dentry = a->dst_wh_dentry;
+		err = au_wh_unlink_dentry(a->dst_h_dir, &a->h_path,
+					  a->dst_dentry);
+		if (unlikely(err))
+			goto out_diropq;
+	}
+
+	/* remove whtmp */
+	if (a->thargs)
+		au_ren_del_whtmp(a); /* ignore this error */
+
+	err = 0;
+	goto out_success;
+
+ out_diropq:
+	if (au_ftest_ren(a->flags, DIROPQ))
+		au_ren_rev_diropq(err, a);
+ out_rename:
+	if (!au_ftest_ren(a->flags, CPUP))
+		au_ren_rev_rename(err, a);
+	else
+		au_ren_rev_cpup(err, a);
+ out_whtmp:
+	if (a->thargs)
+		au_ren_rev_whtmp(err, a);
+ out_whdst:
+	dput(a->dst_wh_dentry);
+	a->dst_wh_dentry = NULL;
+ out_whsrc:
+	if (a->src_wh_dentry)
+		au_ren_rev_whsrc(err, a);
+	au_ren_rev_drop(a);
+ out_success:
+	dput(a->src_wh_dentry);
+	dput(a->dst_wh_dentry);
+ out_thargs:
+	if (a->thargs) {
+		dput(a->h_dst);
+		au_whtmp_rmdir_free(a->thargs);
+		a->thargs = NULL;
+	}
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * test if @dentry dir can be rename destination or not.
+ * success means, it is a logically empty dir.
+ */
+static int may_rename_dstdir(struct dentry *dentry, struct au_nhash *whlist)
+{
+	return au_test_empty(dentry, whlist);
+}
+
+/*
+ * test if @dentry dir can be rename source or not.
+ * if it can, return 0 and @children is filled.
+ * success means,
+ * - it is a logically empty dir.
+ * - or, it exists on writable branch and has no children including whiteouts
+ *       on the lower branch.
+ */
+static int may_rename_srcdir(struct dentry *dentry, aufs_bindex_t btgt)
+{
+	int err;
+	aufs_bindex_t bstart;
+
+	bstart = au_dbstart(dentry);
+	if (bstart != btgt) {
+		struct au_nhash whlist;
+
+		SiMustAnyLock(dentry->d_sb);
+		err = au_nhash_alloc(&whlist, au_sbi(dentry->d_sb)->si_rdhash,
+				     GFP_NOFS);
+		if (unlikely(err))
+			goto out;
+		err = au_test_empty(dentry, &whlist);
+		au_nhash_wh_free(&whlist);
+		goto out;
+	}
+
+	if (bstart == au_dbtaildir(dentry))
+		return 0; /* success */
+
+	err = au_test_empty_lower(dentry);
+
+ out:
+	if (err == -ENOTEMPTY) {
+		AuWarn1("renaming dir who has child(ren) on multiple branches,"
+			" is not supported\n");
+		err = -EXDEV;
+	}
+	return err;
+}
+
+/* side effect: sets whlist and h_dentry */
+static int au_ren_may_dir(struct au_ren_args *a)
+{
+	int err;
+	struct dentry *d;
+
+	d = a->dst_dentry;
+	SiMustAnyLock(d->d_sb);
+	err = au_nhash_alloc(&a->whlist, au_sbi(d->d_sb)->si_rdhash, GFP_NOFS);
+	if (unlikely(err))
+		goto out;
+
+	err = 0;
+	if (au_ftest_ren(a->flags, ISDIR) && a->dst_inode) {
+		au_set_dbstart(d, a->dst_bstart);
+		err = may_rename_dstdir(d, &a->whlist);
+		au_set_dbstart(d, a->btgt);
+	}
+	a->dst_h_dentry = au_h_dptr(d, au_dbstart(d));
+	if (unlikely(err))
+		goto out;
+
+	d = a->src_dentry;
+	a->src_h_dentry = au_h_dptr(d, au_dbstart(d));
+	if (au_ftest_ren(a->flags, ISDIR)) {
+		err = may_rename_srcdir(d, a->btgt);
+		if (unlikely(err)) {
+			au_nhash_wh_free(&a->whlist);
+			a->whlist.nh_num = 0;
+		}
+	}
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * simple tests for rename.
+ * following the checks in vfs, plus the parent-child relationship.
+ */
+static int au_may_ren(struct au_ren_args *a)
+{
+	int err, isdir;
+	struct inode *h_inode;
+
+	if (a->src_bstart == a->btgt) {
+		err = au_may_del(a->src_dentry, a->btgt, a->src_h_parent,
+				 au_ftest_ren(a->flags, ISDIR));
+		if (unlikely(err))
+			goto out;
+		err = -EINVAL;
+		if (unlikely(a->src_h_dentry == a->h_trap))
+			goto out;
+	}
+
+	err = 0;
+	if (a->dst_bstart != a->btgt)
+		goto out;
+
+	err = -EIO;
+	h_inode = a->dst_h_dentry->d_inode;
+	isdir = !!au_ftest_ren(a->flags, ISDIR);
+	if (!a->dst_dentry->d_inode) {
+		if (unlikely(h_inode))
+			goto out;
+		err = au_may_add(a->dst_dentry, a->btgt, a->dst_h_parent,
+				 isdir);
+	} else {
+		if (unlikely(!h_inode || !h_inode->i_nlink))
+			goto out;
+		err = au_may_del(a->dst_dentry, a->btgt, a->dst_h_parent,
+				 isdir);
+		if (unlikely(err))
+			goto out;
+		err = -ENOTEMPTY;
+		if (unlikely(a->dst_h_dentry == a->h_trap))
+			goto out;
+		err = 0;
+	}
+
+ out:
+	if (unlikely(err == -ENOENT || err == -EEXIST))
+		err = -EIO;
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * locking order
+ * (VFS)
+ * - src_dir and dir by lock_rename()
+ * - inode if exitsts
+ * (aufs)
+ * - lock all
+ *   + src_dentry and dentry by aufs_read_and_write_lock2() which calls,
+ *     + si_read_lock
+ *     + di_write_lock2_child()
+ *       + di_write_lock_child()
+ *	   + ii_write_lock_child()
+ *       + di_write_lock_child2()
+ *	   + ii_write_lock_child2()
+ *     + src_parent and parent
+ *       + di_write_lock_parent()
+ *	   + ii_write_lock_parent()
+ *       + di_write_lock_parent2()
+ *	   + ii_write_lock_parent2()
+ *   + lower src_dir and dir by vfsub_lock_rename()
+ *   + verify the every relationships between child and parent. if any
+ *     of them failed, unlock all and return -EBUSY.
+ */
+static void au_ren_unlock(struct au_ren_args *a)
+{
+	struct super_block *sb;
+
+	sb = a->dst_dentry->d_sb;
+	if (au_ftest_ren(a->flags, MNT_WRITE))
+		mnt_drop_write(a->br->br_mnt);
+	vfsub_unlock_rename(a->src_h_parent, a->src_hdir,
+			    a->dst_h_parent, a->dst_hdir);
+}
+
+static int au_ren_lock(struct au_ren_args *a)
+{
+	int err;
+	unsigned int udba;
+
+	err = 0;
+	a->src_h_parent = au_h_dptr(a->src_parent, a->btgt);
+	a->src_hdir = au_hi(a->src_dir, a->btgt);
+	a->dst_h_parent = au_h_dptr(a->dst_parent, a->btgt);
+	a->dst_hdir = au_hi(a->dst_dir, a->btgt);
+	a->h_trap = vfsub_lock_rename(a->src_h_parent, a->src_hdir,
+				      a->dst_h_parent, a->dst_hdir);
+	udba = au_opt_udba(a->src_dentry->d_sb);
+	if (unlikely(a->src_hdir->hi_inode != a->src_h_parent->d_inode
+		     || a->dst_hdir->hi_inode != a->dst_h_parent->d_inode))
+		err = au_busy_or_stale();
+	if (!err && au_dbstart(a->src_dentry) == a->btgt)
+		err = au_h_verify(a->src_h_dentry, udba,
+				  a->src_h_parent->d_inode, a->src_h_parent,
+				  a->br);
+	if (!err && au_dbstart(a->dst_dentry) == a->btgt)
+		err = au_h_verify(a->dst_h_dentry, udba,
+				  a->dst_h_parent->d_inode, a->dst_h_parent,
+				  a->br);
+	if (!err) {
+		err = mnt_want_write(a->br->br_mnt);
+		if (unlikely(err))
+			goto out_unlock;
+		au_fset_ren(a->flags, MNT_WRITE);
+		goto out; /* success */
+	}
+
+	err = au_busy_or_stale();
+
+ out_unlock:
+	au_ren_unlock(a);
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void au_ren_refresh_dir(struct au_ren_args *a)
+{
+	struct inode *dir;
+
+	dir = a->dst_dir;
+	dir->i_version++;
+	if (au_ftest_ren(a->flags, ISDIR)) {
+		/* is this updating defined in POSIX? */
+		au_cpup_attr_timesizes(a->src_inode);
+		au_cpup_attr_nlink(dir, /*force*/1);
+		if (a->dst_inode) {
+			clear_nlink(a->dst_inode);
+			au_cpup_attr_timesizes(a->dst_inode);
+		}
+	}
+	if (au_ibstart(dir) == a->btgt)
+		au_cpup_attr_timesizes(dir);
+
+	if (au_ftest_ren(a->flags, ISSAMEDIR))
+		return;
+
+	dir = a->src_dir;
+	dir->i_version++;
+	if (au_ftest_ren(a->flags, ISDIR))
+		au_cpup_attr_nlink(dir, /*force*/1);
+	if (au_ibstart(dir) == a->btgt)
+		au_cpup_attr_timesizes(dir);
+}
+
+static void au_ren_refresh(struct au_ren_args *a)
+{
+	aufs_bindex_t bend, bindex;
+	struct dentry *d, *h_d;
+	struct inode *i, *h_i;
+	struct super_block *sb;
+
+	d = a->src_dentry;
+	au_set_dbwh(d, -1);
+	bend = au_dbend(d);
+	for (bindex = a->btgt + 1; bindex <= bend; bindex++) {
+		h_d = au_h_dptr(d, bindex);
+		if (h_d)
+			au_set_h_dptr(d, bindex, NULL);
+	}
+	au_set_dbend(d, a->btgt);
+
+	sb = d->d_sb;
+	i = a->src_inode;
+	if (au_opt_test(au_mntflags(sb), PLINK) && au_plink_test(i))
+		return; /* success */
+
+	bend = au_ibend(i);
+	for (bindex = a->btgt + 1; bindex <= bend; bindex++) {
+		h_i = au_h_iptr(i, bindex);
+		if (h_i) {
+			au_xino_write(sb, bindex, h_i->i_ino, /*ino*/0);
+			/* ignore this error */
+			au_set_h_iptr(i, bindex, NULL, 0);
+		}
+	}
+	au_set_ibend(i, a->btgt);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* mainly for link(2) and rename(2) */
+int au_wbr(struct dentry *dentry, aufs_bindex_t btgt)
+{
+	aufs_bindex_t bdiropq, bwh;
+	struct dentry *parent;
+	struct au_branch *br;
+
+	parent = dentry->d_parent;
+	IMustLock(parent->d_inode); /* dir is locked */
+
+	bdiropq = au_dbdiropq(parent);
+	bwh = au_dbwh(dentry);
+	br = au_sbr(dentry->d_sb, btgt);
+	if (au_br_rdonly(br)
+	    || (0 <= bdiropq && bdiropq < btgt)
+	    || (0 <= bwh && bwh < btgt))
+		btgt = -1;
+
+	AuDbg("btgt %d\n", btgt);
+	return btgt;
+}
+
+/* sets src_bstart, dst_bstart and btgt */
+static int au_ren_wbr(struct au_ren_args *a)
+{
+	int err;
+	struct au_wr_dir_args wr_dir_args = {
+		/* .force_btgt	= -1, */
+		.flags		= AuWrDir_ADD_ENTRY
+	};
+
+	a->src_bstart = au_dbstart(a->src_dentry);
+	a->dst_bstart = au_dbstart(a->dst_dentry);
+	if (au_ftest_ren(a->flags, ISDIR))
+		au_fset_wrdir(wr_dir_args.flags, ISDIR);
+	wr_dir_args.force_btgt = a->src_bstart;
+	if (a->dst_inode && a->dst_bstart < a->src_bstart)
+		wr_dir_args.force_btgt = a->dst_bstart;
+	wr_dir_args.force_btgt = au_wbr(a->dst_dentry, wr_dir_args.force_btgt);
+	err = au_wr_dir(a->dst_dentry, a->src_dentry, &wr_dir_args);
+	a->btgt = err;
+
+	return err;
+}
+
+static void au_ren_dt(struct au_ren_args *a)
+{
+	a->h_path.dentry = a->src_h_parent;
+	au_dtime_store(a->src_dt + AuPARENT, a->src_parent, &a->h_path);
+	if (!au_ftest_ren(a->flags, ISSAMEDIR)) {
+		a->h_path.dentry = a->dst_h_parent;
+		au_dtime_store(a->dst_dt + AuPARENT, a->dst_parent, &a->h_path);
+	}
+
+	au_fclr_ren(a->flags, DT_DSTDIR);
+	if (!au_ftest_ren(a->flags, ISDIR))
+		return;
+
+	a->h_path.dentry = a->src_h_dentry;
+	au_dtime_store(a->src_dt + AuCHILD, a->src_dentry, &a->h_path);
+	if (a->dst_h_dentry->d_inode) {
+		au_fset_ren(a->flags, DT_DSTDIR);
+		a->h_path.dentry = a->dst_h_dentry;
+		au_dtime_store(a->dst_dt + AuCHILD, a->dst_dentry, &a->h_path);
+	}
+}
+
+static void au_ren_rev_dt(int err, struct au_ren_args *a)
+{
+	struct dentry *h_d;
+	struct mutex *h_mtx;
+
+	au_dtime_revert(a->src_dt + AuPARENT);
+	if (!au_ftest_ren(a->flags, ISSAMEDIR))
+		au_dtime_revert(a->dst_dt + AuPARENT);
+
+	if (au_ftest_ren(a->flags, ISDIR) && err != -EIO) {
+		h_d = a->src_dt[AuCHILD].dt_h_path.dentry;
+		h_mtx = &h_d->d_inode->i_mutex;
+		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+		au_dtime_revert(a->src_dt + AuCHILD);
+		mutex_unlock(h_mtx);
+
+		if (au_ftest_ren(a->flags, DT_DSTDIR)) {
+			h_d = a->dst_dt[AuCHILD].dt_h_path.dentry;
+			h_mtx = &h_d->d_inode->i_mutex;
+			mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+			au_dtime_revert(a->dst_dt + AuCHILD);
+			mutex_unlock(h_mtx);
+		}
+	}
+}
+
+/* ---------------------------------------------------------------------- */
+
+int aufs_rename(struct inode *_src_dir, struct dentry *_src_dentry,
+		struct inode *_dst_dir, struct dentry *_dst_dentry)
+{
+	int err;
+	/* reduce stack space */
+	struct au_ren_args *a;
+
+	IMustLock(_src_dir);
+	IMustLock(_dst_dir);
+
+	err = -ENOMEM;
+	BUILD_BUG_ON(sizeof(*a) > PAGE_SIZE);
+	a = kzalloc(sizeof(*a), GFP_NOFS);
+	if (unlikely(!a))
+		goto out;
+
+	a->src_dir = _src_dir;
+	a->src_dentry = _src_dentry;
+	a->src_inode = a->src_dentry->d_inode;
+	a->src_parent = a->src_dentry->d_parent; /* dir inode is locked */
+	a->dst_dir = _dst_dir;
+	a->dst_dentry = _dst_dentry;
+	a->dst_inode = a->dst_dentry->d_inode;
+	a->dst_parent = a->dst_dentry->d_parent; /* dir inode is locked */
+	if (a->dst_inode) {
+		IMustLock(a->dst_inode);
+		au_igrab(a->dst_inode);
+	}
+
+	err = -ENOTDIR;
+	if (S_ISDIR(a->src_inode->i_mode)) {
+		au_fset_ren(a->flags, ISDIR);
+		if (unlikely(a->dst_inode && !S_ISDIR(a->dst_inode->i_mode)))
+			goto out_free;
+		aufs_read_and_write_lock2(a->dst_dentry, a->src_dentry,
+					  AuLock_DIR | AuLock_FLUSH);
+	} else
+		aufs_read_and_write_lock2(a->dst_dentry, a->src_dentry,
+					  AuLock_FLUSH);
+
+	au_fset_ren(a->flags, ISSAMEDIR); /* temporary */
+	di_write_lock_parent(a->dst_parent);
+
+	/* which branch we process */
+	err = au_ren_wbr(a);
+	if (unlikely(err < 0))
+		goto out_unlock;
+	a->br = au_sbr(a->dst_dentry->d_sb, a->btgt);
+	a->h_path.mnt = a->br->br_mnt;
+
+	/* are they available to be renamed */
+	err = au_ren_may_dir(a);
+	if (unlikely(err))
+		goto out_unlock;
+
+	/* prepare the writable parent dir on the same branch */
+	if (a->dst_bstart == a->btgt) {
+		au_fset_ren(a->flags, WHDST);
+	} else {
+		err = au_cpup_dirs(a->dst_dentry, a->btgt);
+		if (unlikely(err))
+			goto out_children;
+	}
+
+	if (a->src_dir != a->dst_dir) {
+		/*
+		 * this temporary unlock is safe,
+		 * because both dir->i_mutex are locked.
+		 */
+		di_write_unlock(a->dst_parent);
+		di_write_lock_parent(a->src_parent);
+		err = au_wr_dir_need_wh(a->src_dentry,
+					au_ftest_ren(a->flags, ISDIR),
+					&a->btgt);
+		di_write_unlock(a->src_parent);
+		di_write_lock2_parent(a->src_parent, a->dst_parent, /*isdir*/1);
+		au_fclr_ren(a->flags, ISSAMEDIR);
+	} else
+		err = au_wr_dir_need_wh(a->src_dentry,
+					au_ftest_ren(a->flags, ISDIR),
+					&a->btgt);
+	if (unlikely(err < 0))
+		goto out_children;
+	if (err)
+		au_fset_ren(a->flags, WHSRC);
+
+	/* lock them all */
+	err = au_ren_lock(a);
+	if (unlikely(err))
+		goto out_children;
+
+	if (!au_opt_test(au_mntflags(a->dst_dir->i_sb), UDBA_NONE)) {
+		err = au_may_ren(a);
+		if (unlikely(err))
+			goto out_hdir;
+	}
+
+	/* store timestamps to be revertible */
+	au_ren_dt(a);
+
+	/* here we go */
+	err = do_rename(a);
+	if (unlikely(err))
+		goto out_dt;
+
+	/* update dir attributes */
+	au_ren_refresh_dir(a);
+
+	/* dput/iput all lower dentries */
+	au_ren_refresh(a);
+
+	goto out_hdir; /* success */
+
+ out_dt:
+	au_ren_rev_dt(err, a);
+ out_hdir:
+	au_ren_unlock(a);
+ out_children:
+	au_nhash_wh_free(&a->whlist);
+ out_unlock:
+	if (unlikely(err && au_ftest_ren(a->flags, ISDIR))) {
+		au_update_dbstart(a->dst_dentry);
+		d_drop(a->dst_dentry);
+	}
+	if (!err)
+		d_move(a->src_dentry, a->dst_dentry);
+	if (au_ftest_ren(a->flags, ISSAMEDIR))
+		di_write_unlock(a->dst_parent);
+	else
+		di_write_unlock2(a->src_parent, a->dst_parent);
+	aufs_read_and_write_unlock2(a->dst_dentry, a->src_dentry);
+ out_free:
+	iput(a->dst_inode);
+	if (a->thargs)
+		au_whtmp_rmdir_free(a->thargs);
+	kfree(a);
+ out:
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/Kconfig linux-2.6.31.4/fs/aufs/Kconfig
--- linux-2.6.31.4.orig/fs/aufs/Kconfig	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/Kconfig	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,132 @@
+config AUFS_FS
+	tristate "Aufs (Advanced multi layered unification filesystem) support"
+	depends on EXPERIMENTAL
+	help
+	Aufs is a stackable unification filesystem such as Unionfs,
+	which unifies several directories and provides a merged single
+	directory.
+	In the early days, aufs was entirely re-designed and
+	re-implemented Unionfs Version 1.x series. Introducing many
+	original ideas, approaches and improvements, it becomes totally
+	different from Unionfs while keeping the basic features.
+
+if AUFS_FS
+choice
+	prompt "Maximum number of branches"
+	default AUFS_BRANCH_MAX_127
+	help
+	Specifies the maximum number of branches (or member directories)
+	in a single aufs. The larger value consumes more system
+	resources and has a minor impact to performance.
+config AUFS_BRANCH_MAX_127
+	bool "127"
+	help
+	Specifies the maximum number of branches (or member directories)
+	in a single aufs. The larger value consumes more system
+	resources and has a minor impact to performance.
+config AUFS_BRANCH_MAX_511
+	bool "511"
+	help
+	Specifies the maximum number of branches (or member directories)
+	in a single aufs. The larger value consumes more system
+	resources and has a minor impact to performance.
+config AUFS_BRANCH_MAX_1023
+	bool "1023"
+	help
+	Specifies the maximum number of branches (or member directories)
+	in a single aufs. The larger value consumes more system
+	resources and has a minor impact to performance.
+config AUFS_BRANCH_MAX_32767
+	bool "32767"
+	help
+	Specifies the maximum number of branches (or member directories)
+	in a single aufs. The larger value consumes more system
+	resources and has a minor impact to performance.
+endchoice
+
+config AUFS_HINOTIFY
+	bool "Use inotify to detect actions on a branch"
+	depends on INOTIFY
+	help
+	If you want to modify files on branches directly, eg. bypassing aufs,
+	and want aufs to detect the changes of them fully, then enable this
+	option and use 'udba=inotify' mount option.
+	It will have a negative impact to the performance.
+	See detail in aufs.5.
+
+config AUFS_EXPORT
+	bool "NFS-exportable aufs"
+	depends on (AUFS_FS = y && EXPORTFS = y) || (AUFS_FS = m && EXPORTFS)
+	help
+	If you want to export your mounted aufs via NFS, then enable this
+	option. There are several requirements for this configuration.
+	See detail in aufs.5.
+
+config AUFS_SHWH
+	bool "Show whiteouts"
+	help
+	If you want to make the whiteouts in aufs visible, then enable
+	this option and specify 'shwh' mount option. Although it may
+	sounds like philosophy or something, but in technically it
+	simply shows the name of whiteout with keeping its behaviour.
+
+config AUFS_BR_RAMFS
+	bool "Ramfs (initramfs/rootfs) as an aufs branch"
+	help
+	If you want to use ramfs as an aufs branch fs, then enable this
+	option. Generally tmpfs is recommended.
+	Aufs prohibited them to be a branch fs by default, because
+	initramfs becomes unusable after switch_root or something
+	generally. If you sets initramfs as an aufs branch and boot your
+	system by switch_root, you will meet a problem easily since the
+	files in initramfs may be inaccessible.
+	Unless you are going to use ramfs as an aufs branch fs without
+	switch_root or something, leave it N.
+
+config AUFS_BR_FUSE
+	bool "Fuse fs as an aufs branch"
+	depends on FUSE_FS
+	select AUFS_POLL
+	help
+	If you want to use fuse-based userspace filesystem as an aufs
+	branch fs, then enable this option.
+	It implements the internal poll(2) operation which is
+	implemented by fuse only (curretnly).
+
+config AUFS_DEBUG
+	bool "Debug aufs"
+	help
+	Enable this to compile aufs internal debug code.
+	It will have a negative impact to the performance.
+
+config AUFS_MAGIC_SYSRQ
+	bool
+	depends on AUFS_DEBUG && MAGIC_SYSRQ
+	default y
+	help
+	Automatic configuration for internal use.
+	When aufs supports Magic SysRq, enabled automatically.
+
+config AUFS_BDEV_LOOP
+	bool
+	depends on BLK_DEV_LOOP
+	default y
+	help
+	Automatic configuration for internal use.
+	Convert =[ym] into =y.
+
+config AUFS_INO_T_64
+	bool
+	depends on AUFS_EXPORT
+	depends on 64BIT && !(ALPHA || S390)
+	default y
+	help
+	Automatic configuration for internal use.
+	/* typedef unsigned long/int __kernel_ino_t */
+	/* alpha and s390x are int */
+
+config AUFS_POLL
+	bool
+	help
+	Automatic configuration for internal use.
+endif
diff -Nur linux-2.6.31.4.orig/fs/aufs/loop.c linux-2.6.31.4/fs/aufs/loop.c
--- linux-2.6.31.4.orig/fs/aufs/loop.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/loop.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * support for loopback block device as a branch
+ */
+
+#include <linux/loop.h>
+#include "aufs.h"
+
+/*
+ * test if two lower dentries have overlapping branches.
+ */
+int au_test_loopback_overlap(struct super_block *sb, struct dentry *h_d1,
+			     struct dentry *h_d2)
+{
+	struct inode *h_inode;
+	struct loop_device *l;
+
+	h_inode = h_d1->d_inode;
+	if (MAJOR(h_inode->i_sb->s_dev) != LOOP_MAJOR)
+		return 0;
+
+	l = h_inode->i_sb->s_bdev->bd_disk->private_data;
+	h_d1 = l->lo_backing_file->f_dentry;
+	/* h_d1 can be local NFS. in this case aufs cannot detect the loop */
+	if (unlikely(h_d1->d_sb == sb))
+		return 1;
+	return !!au_test_subdir(h_d1, h_d2);
+}
+
+/* true if a kernel thread named 'loop[0-9].*' accesses a file */
+int au_test_loopback_kthread(void)
+{
+	const char c = current->comm[4];
+
+	return current->mm == NULL
+	       && '0' <= c && c <= '9'
+	       && strncmp(current->comm, "loop", 4) == 0;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/loop.h linux-2.6.31.4/fs/aufs/loop.h
--- linux-2.6.31.4.orig/fs/aufs/loop.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/loop.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * support for loopback mount as a branch
+ */
+
+#ifndef __AUFS_LOOP_H__
+#define __AUFS_LOOP_H__
+
+#ifdef __KERNEL__
+
+struct dentry;
+struct super_block;
+
+#ifdef CONFIG_AUFS_BDEV_LOOP
+/* loop.c */
+int au_test_loopback_overlap(struct super_block *sb, struct dentry *h_d1,
+			     struct dentry *h_d2);
+int au_test_loopback_kthread(void);
+#else
+static inline
+int au_test_loopback_overlap(struct super_block *sb, struct dentry *h_d1,
+			     struct dentry *h_d2)
+{
+	return 0;
+}
+
+static inline int au_test_loopback_kthread(void)
+{
+	return 0;
+}
+#endif /* BLK_DEV_LOOP */
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_LOOP_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/magic.mk linux-2.6.31.4/fs/aufs/magic.mk
--- linux-2.6.31.4.orig/fs/aufs/magic.mk	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/magic.mk	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,52 @@
+
+# defined in ${srctree}/fs/fuse/inode.c
+# tristate
+ifdef CONFIG_FUSE_FS
+ccflags-y += -DFUSE_SUPER_MAGIC=0x65735546
+endif
+
+# defined in ${srctree}/fs/ocfs2/ocfs2_fs.h
+# tristate
+ifdef CONFIG_OCFS2_FS
+ccflags-y += -DOCFS2_SUPER_MAGIC=0x7461636f
+endif
+
+# defined in ${srctree}/fs/ocfs2/dlm/userdlm.h
+# tristate
+ifdef CONFIG_OCFS2_FS_O2CB
+ccflags-y += -DDLMFS_MAGIC=0x76a9f425
+endif
+
+# defined in ${srctree}/fs/ramfs/inode.c
+# always true
+ccflags-y += -DRAMFS_MAGIC=0x858458f6
+
+# defined in ${srctree}/fs/cifs/cifsfs.c
+# tristate
+ifdef CONFIG_CIFS_FS
+ccflags-y += -DCIFS_MAGIC_NUMBER=0xFF534D42
+endif
+
+# defined in ${srctree}/fs/xfs/xfs_sb.h
+# tristate
+ifdef CONFIG_XFS_FS
+ccflags-y += -DXFS_SB_MAGIC=0x58465342
+endif
+
+# defined in ${srctree}/fs/configfs/mount.c
+# tristate
+ifdef CONFIG_CONFIGFS_FS
+ccflags-y += -DCONFIGFS_MAGIC=0x62656570
+endif
+
+# defined in ${srctree}/fs/9p/v9fs.h
+# tristate
+ifdef CONFIG_9P_FS
+ccflags-y += -DV9FS_MAGIC=0x01021997
+endif
+
+# defined in ${srctree}/fs/ubifs/ubifs.h
+# tristate
+ifdef CONFIG_UBIFS_FS
+ccflags-y += -DUBIFS_SUPER_MAGIC=0x24051905
+endif
diff -Nur linux-2.6.31.4.orig/fs/aufs/Makefile linux-2.6.31.4/fs/aufs/Makefile
--- linux-2.6.31.4.orig/fs/aufs/Makefile	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/Makefile	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,23 @@
+
+include ${src}/magic.mk
+-include ${src}/priv_def.mk
+
+obj-$(CONFIG_AUFS_FS) += aufs.o
+aufs-y := module.o sbinfo.o super.o branch.o xino.o sysaufs.o opts.o \
+	wkq.o vfsub.o dcsub.o \
+	cpup.o whout.o plink.o wbr_policy.o \
+	dinfo.o dentry.o \
+	finfo.o file.o f_op.o \
+	dir.o vdir.o \
+	iinfo.o inode.o i_op.o i_op_add.o i_op_del.o i_op_ren.o \
+	ioctl.o
+
+# all are boolean
+aufs-$(CONFIG_SYSFS) += sysfs.o
+aufs-$(CONFIG_DEBUG_FS) += dbgaufs.o
+aufs-$(CONFIG_AUFS_BDEV_LOOP) += loop.o
+aufs-$(CONFIG_AUFS_HINOTIFY) += hinotify.o
+aufs-$(CONFIG_AUFS_EXPORT) += export.o
+aufs-$(CONFIG_AUFS_POLL) += poll.o
+aufs-$(CONFIG_AUFS_DEBUG) += debug.o
+aufs-$(CONFIG_AUFS_MAGIC_SYSRQ) += sysrq.o
diff -Nur linux-2.6.31.4.orig/fs/aufs/module.c linux-2.6.31.4/fs/aufs/module.c
--- linux-2.6.31.4.orig/fs/aufs/module.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/module.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,173 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * module global variables and operations
+ */
+
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include "aufs.h"
+
+void *au_kzrealloc(void *p, unsigned int nused, unsigned int new_sz, gfp_t gfp)
+{
+	if (new_sz <= nused)
+		return p;
+
+	p = krealloc(p, new_sz, gfp);
+	if (p)
+		memset(p + nused, 0, new_sz - nused);
+	return p;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * aufs caches
+ */
+struct kmem_cache *au_cachep[AuCache_Last];
+static int __init au_cache_init(void)
+{
+	au_cachep[AuCache_DINFO] = AuCache(au_dinfo);
+	if (au_cachep[AuCache_DINFO])
+		au_cachep[AuCache_ICNTNR] = AuCache(au_icntnr);
+	if (au_cachep[AuCache_ICNTNR])
+		au_cachep[AuCache_FINFO] = AuCache(au_finfo);
+	if (au_cachep[AuCache_FINFO])
+		au_cachep[AuCache_VDIR] = AuCache(au_vdir);
+	if (au_cachep[AuCache_VDIR])
+		au_cachep[AuCache_DEHSTR] = AuCache(au_vdir_dehstr);
+	if (au_cachep[AuCache_DEHSTR])
+		return 0;
+
+	return -ENOMEM;
+}
+
+static void au_cache_fin(void)
+{
+	int i;
+	for (i = 0; i < AuCache_Last; i++)
+		if (au_cachep[i]) {
+			kmem_cache_destroy(au_cachep[i]);
+			au_cachep[i] = NULL;
+		}
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_dir_roflags;
+
+/*
+ * functions for module interface.
+ */
+MODULE_LICENSE("GPL");
+/* MODULE_LICENSE("GPL v2"); */
+MODULE_AUTHOR("Junjiro R. Okajima <aufs-users@lists.sourceforge.net>");
+MODULE_DESCRIPTION(AUFS_NAME
+	" -- Advanced multi layered unification filesystem");
+MODULE_VERSION(AUFS_VERSION);
+
+/* it should be 'byte', but param_set_byte() prints it by "%c" */
+short aufs_nwkq = AUFS_NWKQ_DEF;
+MODULE_PARM_DESC(nwkq, "the number of workqueue thread, " AUFS_WKQ_NAME);
+module_param_named(nwkq, aufs_nwkq, short, S_IRUGO);
+
+/* this module parameter has no meaning when SYSFS is disabled */
+int sysaufs_brs = 1;
+MODULE_PARM_DESC(brs, "use <sysfs>/fs/aufs/si_*/brN");
+module_param_named(brs, sysaufs_brs, int, S_IRUGO);
+
+/* ---------------------------------------------------------------------- */
+
+static char au_esc_chars[0x20 + 3]; /* 0x01-0x20, backslash, del, and NULL */
+
+int au_seq_path(struct seq_file *seq, struct path *path)
+{
+	return seq_path(seq, path, au_esc_chars);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int __init aufs_init(void)
+{
+	int err, i;
+	char *p;
+
+	p = au_esc_chars;
+	for (i = 1; i <= ' '; i++)
+		*p++ = i;
+	*p++ = '\\';
+	*p++ = '\x7f';
+	*p = 0;
+
+	au_dir_roflags = au_file_roflags(O_DIRECTORY | O_LARGEFILE);
+
+	sysaufs_brs_init();
+	au_debug_init();
+
+	err = -EINVAL;
+	if (unlikely(aufs_nwkq <= 0))
+		goto out;
+
+	err = sysaufs_init();
+	if (unlikely(err))
+		goto out;
+	err = au_wkq_init();
+	if (unlikely(err))
+		goto out_sysaufs;
+	err = au_hinotify_init();
+	if (unlikely(err))
+		goto out_wkq;
+	err = au_sysrq_init();
+	if (unlikely(err))
+		goto out_hin;
+	err = au_cache_init();
+	if (unlikely(err))
+		goto out_sysrq;
+	err = register_filesystem(&aufs_fs_type);
+	if (unlikely(err))
+		goto out_cache;
+	pr_info(AUFS_NAME " " AUFS_VERSION "\n");
+	goto out; /* success */
+
+ out_cache:
+	au_cache_fin();
+ out_sysrq:
+	au_sysrq_fin();
+ out_hin:
+	au_hinotify_fin();
+ out_wkq:
+	au_wkq_fin();
+ out_sysaufs:
+	sysaufs_fin();
+ out:
+	return err;
+}
+
+static void __exit aufs_exit(void)
+{
+	unregister_filesystem(&aufs_fs_type);
+	au_cache_fin();
+	au_sysrq_fin();
+	au_hinotify_fin();
+	au_wkq_fin();
+	sysaufs_fin();
+}
+
+module_init(aufs_init);
+module_exit(aufs_exit);
diff -Nur linux-2.6.31.4.orig/fs/aufs/module.h linux-2.6.31.4/fs/aufs/module.h
--- linux-2.6.31.4.orig/fs/aufs/module.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/module.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * module initialization and module-global
+ */
+
+#ifndef __AUFS_MODULE_H__
+#define __AUFS_MODULE_H__
+
+#ifdef __KERNEL__
+
+#include <linux/slab.h>
+
+struct path;
+struct seq_file;
+
+/* module parameters */
+extern short aufs_nwkq;
+extern int sysaufs_brs;
+
+/* ---------------------------------------------------------------------- */
+
+extern int au_dir_roflags;
+
+void *au_kzrealloc(void *p, unsigned int nused, unsigned int new_sz, gfp_t gfp);
+int au_seq_path(struct seq_file *seq, struct path *path);
+
+/* ---------------------------------------------------------------------- */
+
+/* kmem cache */
+enum {
+	AuCache_DINFO,
+	AuCache_ICNTNR,
+	AuCache_FINFO,
+	AuCache_VDIR,
+	AuCache_DEHSTR,
+#ifdef CONFIG_AUFS_HINOTIFY
+	AuCache_HINOTIFY,
+#endif
+	AuCache_Last
+};
+
+#define AuCache(type)	KMEM_CACHE(type, SLAB_RECLAIM_ACCOUNT)
+
+extern struct kmem_cache *au_cachep[];
+
+#define AuCacheFuncs(name, index) \
+static inline void *au_cache_alloc_##name(void) \
+{ return kmem_cache_alloc(au_cachep[AuCache_##index], GFP_NOFS); } \
+static inline void au_cache_free_##name(void *p) \
+{ kmem_cache_free(au_cachep[AuCache_##index], p); }
+
+AuCacheFuncs(dinfo, DINFO);
+AuCacheFuncs(icntnr, ICNTNR);
+AuCacheFuncs(finfo, FINFO);
+AuCacheFuncs(vdir, VDIR);
+AuCacheFuncs(dehstr, DEHSTR);
+
+/*  ---------------------------------------------------------------------- */
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_MODULE_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/opts.c linux-2.6.31.4/fs/aufs/opts.c
--- linux-2.6.31.4.orig/fs/aufs/opts.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/opts.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,1543 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * mount options/flags
+ */
+
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/types.h> /* a distribution requires */
+#include <linux/parser.h>
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+enum {
+	Opt_br,
+	Opt_add, Opt_del, Opt_mod, Opt_reorder, Opt_append, Opt_prepend,
+	Opt_idel, Opt_imod, Opt_ireorder,
+	Opt_dirwh, Opt_rdcache, Opt_rdblk, Opt_rdhash, Opt_rendir,
+	Opt_rdblk_def, Opt_rdhash_def,
+	Opt_xino, Opt_zxino, Opt_noxino,
+	Opt_trunc_xino, Opt_trunc_xino_v, Opt_notrunc_xino,
+	Opt_trunc_xino_path, Opt_itrunc_xino,
+	Opt_trunc_xib, Opt_notrunc_xib,
+	Opt_shwh, Opt_noshwh,
+	Opt_plink, Opt_noplink, Opt_list_plink,
+	Opt_udba,
+	/* Opt_lock, Opt_unlock, */
+	Opt_cmd, Opt_cmd_args,
+	Opt_diropq_a, Opt_diropq_w,
+	Opt_warn_perm, Opt_nowarn_perm,
+	Opt_wbr_copyup, Opt_wbr_create,
+	Opt_refrof, Opt_norefrof,
+	Opt_verbose, Opt_noverbose,
+	Opt_sum, Opt_nosum, Opt_wsum,
+	Opt_tail, Opt_ignore, Opt_ignore_silent, Opt_err
+};
+
+static match_table_t options = {
+	{Opt_br, "br=%s"},
+	{Opt_br, "br:%s"},
+
+	{Opt_add, "add=%d:%s"},
+	{Opt_add, "add:%d:%s"},
+	{Opt_add, "ins=%d:%s"},
+	{Opt_add, "ins:%d:%s"},
+	{Opt_append, "append=%s"},
+	{Opt_append, "append:%s"},
+	{Opt_prepend, "prepend=%s"},
+	{Opt_prepend, "prepend:%s"},
+
+	{Opt_del, "del=%s"},
+	{Opt_del, "del:%s"},
+	/* {Opt_idel, "idel:%d"}, */
+	{Opt_mod, "mod=%s"},
+	{Opt_mod, "mod:%s"},
+	/* {Opt_imod, "imod:%d:%s"}, */
+
+	{Opt_dirwh, "dirwh=%d"},
+
+	{Opt_xino, "xino=%s"},
+	{Opt_noxino, "noxino"},
+	{Opt_trunc_xino, "trunc_xino"},
+	{Opt_trunc_xino_v, "trunc_xino_v=%d:%d"},
+	{Opt_notrunc_xino, "notrunc_xino"},
+	{Opt_trunc_xino_path, "trunc_xino=%s"},
+	{Opt_itrunc_xino, "itrunc_xino=%d"},
+	/* {Opt_zxino, "zxino=%s"}, */
+	{Opt_trunc_xib, "trunc_xib"},
+	{Opt_notrunc_xib, "notrunc_xib"},
+
+	{Opt_plink, "plink"},
+	{Opt_noplink, "noplink"},
+#ifdef CONFIG_AUFS_DEBUG
+	{Opt_list_plink, "list_plink"},
+#endif
+
+	{Opt_udba, "udba=%s"},
+
+	{Opt_diropq_a, "diropq=always"},
+	{Opt_diropq_a, "diropq=a"},
+	{Opt_diropq_w, "diropq=whiteouted"},
+	{Opt_diropq_w, "diropq=w"},
+
+	{Opt_warn_perm, "warn_perm"},
+	{Opt_nowarn_perm, "nowarn_perm"},
+
+	/* keep them temporary */
+	{Opt_ignore_silent, "coo=%s"},
+	{Opt_ignore_silent, "nodlgt"},
+	{Opt_ignore_silent, "nodirperm1"},
+	{Opt_ignore_silent, "clean_plink"},
+
+#ifdef CONFIG_AUFS_SHWH
+	{Opt_shwh, "shwh"},
+#endif
+	{Opt_noshwh, "noshwh"},
+
+	{Opt_rendir, "rendir=%d"},
+
+	{Opt_refrof, "refrof"},
+	{Opt_norefrof, "norefrof"},
+
+	{Opt_verbose, "verbose"},
+	{Opt_verbose, "v"},
+	{Opt_noverbose, "noverbose"},
+	{Opt_noverbose, "quiet"},
+	{Opt_noverbose, "q"},
+	{Opt_noverbose, "silent"},
+
+	{Opt_sum, "sum"},
+	{Opt_nosum, "nosum"},
+	{Opt_wsum, "wsum"},
+
+	{Opt_rdcache, "rdcache=%d"},
+	{Opt_rdblk, "rdblk=%d"},
+	{Opt_rdblk_def, "rdblk=def"},
+	{Opt_rdhash, "rdhash=%d"},
+	{Opt_rdhash_def, "rdhash=def"},
+
+	{Opt_wbr_create, "create=%s"},
+	{Opt_wbr_create, "create_policy=%s"},
+	{Opt_wbr_copyup, "cpup=%s"},
+	{Opt_wbr_copyup, "copyup=%s"},
+	{Opt_wbr_copyup, "copyup_policy=%s"},
+
+	/* internal use for the scripts */
+	{Opt_ignore_silent, "si=%s"},
+
+	{Opt_br, "dirs=%s"},
+	{Opt_ignore, "debug=%d"},
+	{Opt_ignore, "delete=whiteout"},
+	{Opt_ignore, "delete=all"},
+	{Opt_ignore, "imap=%s"},
+
+	{Opt_err, NULL}
+};
+
+/* ---------------------------------------------------------------------- */
+
+static const char *au_parser_pattern(int val, struct match_token *token)
+{
+	while (token->pattern) {
+		if (token->token == val)
+			return token->pattern;
+		token++;
+	}
+	BUG();
+	return "??";
+}
+
+/* ---------------------------------------------------------------------- */
+
+static match_table_t brperms = {
+	{AuBrPerm_RO, AUFS_BRPERM_RO},
+	{AuBrPerm_RR, AUFS_BRPERM_RR},
+	{AuBrPerm_RW, AUFS_BRPERM_RW},
+
+	{AuBrPerm_ROWH, AUFS_BRPERM_ROWH},
+	{AuBrPerm_RRWH, AUFS_BRPERM_RRWH},
+	{AuBrPerm_RWNoLinkWH, AUFS_BRPERM_RWNLWH},
+
+	{AuBrPerm_ROWH, "nfsro"},
+	{AuBrPerm_RO, NULL}
+};
+
+static int br_perm_val(char *perm)
+{
+	int val;
+	substring_t args[MAX_OPT_ARGS];
+
+	val = match_token(perm, brperms, args);
+	return val;
+}
+
+const char *au_optstr_br_perm(int brperm)
+{
+	return au_parser_pattern(brperm, (void *)brperms);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static match_table_t udbalevel = {
+	{AuOpt_UDBA_REVAL, "reval"},
+	{AuOpt_UDBA_NONE, "none"},
+#ifdef CONFIG_AUFS_HINOTIFY
+	{AuOpt_UDBA_HINOTIFY, "inotify"},
+#endif
+	{-1, NULL}
+};
+
+static int udba_val(char *str)
+{
+	substring_t args[MAX_OPT_ARGS];
+
+	return match_token(str, udbalevel, args);
+}
+
+const char *au_optstr_udba(int udba)
+{
+	return au_parser_pattern(udba, (void *)udbalevel);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static match_table_t au_wbr_create_policy = {
+	{AuWbrCreate_TDP, "tdp"},
+	{AuWbrCreate_TDP, "top-down-parent"},
+	{AuWbrCreate_RR, "rr"},
+	{AuWbrCreate_RR, "round-robin"},
+	{AuWbrCreate_MFS, "mfs"},
+	{AuWbrCreate_MFS, "most-free-space"},
+	{AuWbrCreate_MFSV, "mfs:%d"},
+	{AuWbrCreate_MFSV, "most-free-space:%d"},
+
+	{AuWbrCreate_MFSRR, "mfsrr:%d"},
+	{AuWbrCreate_MFSRRV, "mfsrr:%d:%d"},
+	{AuWbrCreate_PMFS, "pmfs"},
+	{AuWbrCreate_PMFSV, "pmfs:%d"},
+
+	{-1, NULL}
+};
+
+/*
+ * cf. linux/lib/parser.c and cmdline.c
+ * gave up calling memparse() since it uses simple_strtoull() instead of
+ * strict_...().
+ */
+static int au_match_ull(substring_t *s, unsigned long long *result)
+{
+	int err;
+	unsigned int len;
+	char a[32];
+
+	err = -ERANGE;
+	len = s->to - s->from;
+	if (len + 1 <= sizeof(a)) {
+		memcpy(a, s->from, len);
+		a[len] = '\0';
+		err = strict_strtoull(a, 0, result);
+	}
+	return err;
+}
+
+static int au_wbr_mfs_wmark(substring_t *arg, char *str,
+			    struct au_opt_wbr_create *create)
+{
+	int err;
+	unsigned long long ull;
+
+	err = 0;
+	if (!au_match_ull(arg, &ull))
+		create->mfsrr_watermark = ull;
+	else {
+		AuErr("bad integer in %s\n", str);
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+static int au_wbr_mfs_sec(substring_t *arg, char *str,
+			  struct au_opt_wbr_create *create)
+{
+	int n, err;
+
+	err = 0;
+	if (!match_int(arg, &n) && 0 <= n)
+		create->mfs_second = n;
+	else {
+		AuErr("bad integer in %s\n", str);
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+static int au_wbr_create_val(char *str, struct au_opt_wbr_create *create)
+{
+	int err, e;
+	substring_t args[MAX_OPT_ARGS];
+
+	err = match_token(str, au_wbr_create_policy, args);
+	create->wbr_create = err;
+	switch (err) {
+	case AuWbrCreate_MFSRRV:
+		e = au_wbr_mfs_wmark(&args[0], str, create);
+		if (!e)
+			e = au_wbr_mfs_sec(&args[1], str, create);
+		if (unlikely(e))
+			err = e;
+		break;
+	case AuWbrCreate_MFSRR:
+		e = au_wbr_mfs_wmark(&args[0], str, create);
+		if (unlikely(e)) {
+			err = e;
+			break;
+		}
+		/*FALLTHROUGH*/
+	case AuWbrCreate_MFS:
+	case AuWbrCreate_PMFS:
+		create->mfs_second = AUFS_MFS_SECOND_DEF;
+		break;
+	case AuWbrCreate_MFSV:
+	case AuWbrCreate_PMFSV:
+		e = au_wbr_mfs_sec(&args[0], str, create);
+		if (unlikely(e))
+			err = e;
+		break;
+	}
+
+	return err;
+}
+
+const char *au_optstr_wbr_create(int wbr_create)
+{
+	return au_parser_pattern(wbr_create, (void *)au_wbr_create_policy);
+}
+
+static match_table_t au_wbr_copyup_policy = {
+	{AuWbrCopyup_TDP, "tdp"},
+	{AuWbrCopyup_TDP, "top-down-parent"},
+	{AuWbrCopyup_BUP, "bup"},
+	{AuWbrCopyup_BUP, "bottom-up-parent"},
+	{AuWbrCopyup_BU, "bu"},
+	{AuWbrCopyup_BU, "bottom-up"},
+	{-1, NULL}
+};
+
+static int au_wbr_copyup_val(char *str)
+{
+	substring_t args[MAX_OPT_ARGS];
+
+	return match_token(str, au_wbr_copyup_policy, args);
+}
+
+const char *au_optstr_wbr_copyup(int wbr_copyup)
+{
+	return au_parser_pattern(wbr_copyup, (void *)au_wbr_copyup_policy);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static const int lkup_dirflags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
+
+static void dump_opts(struct au_opts *opts)
+{
+#ifdef CONFIG_AUFS_DEBUG
+	/* reduce stack space */
+	union {
+		struct au_opt_add *add;
+		struct au_opt_del *del;
+		struct au_opt_mod *mod;
+		struct au_opt_xino *xino;
+		struct au_opt_xino_itrunc *xino_itrunc;
+		struct au_opt_wbr_create *create;
+	} u;
+	struct au_opt *opt;
+
+	opt = opts->opt;
+	while (opt->type != Opt_tail) {
+		switch (opt->type) {
+		case Opt_add:
+			u.add = &opt->add;
+			AuDbg("add {b%d, %s, 0x%x, %p}\n",
+				  u.add->bindex, u.add->pathname, u.add->perm,
+				  u.add->path.dentry);
+			break;
+		case Opt_del:
+		case Opt_idel:
+			u.del = &opt->del;
+			AuDbg("del {%s, %p}\n",
+			      u.del->pathname, u.del->h_path.dentry);
+			break;
+		case Opt_mod:
+		case Opt_imod:
+			u.mod = &opt->mod;
+			AuDbg("mod {%s, 0x%x, %p}\n",
+				  u.mod->path, u.mod->perm, u.mod->h_root);
+			break;
+		case Opt_append:
+			u.add = &opt->add;
+			AuDbg("append {b%d, %s, 0x%x, %p}\n",
+				  u.add->bindex, u.add->pathname, u.add->perm,
+				  u.add->path.dentry);
+			break;
+		case Opt_prepend:
+			u.add = &opt->add;
+			AuDbg("prepend {b%d, %s, 0x%x, %p}\n",
+				  u.add->bindex, u.add->pathname, u.add->perm,
+				  u.add->path.dentry);
+			break;
+		case Opt_dirwh:
+			AuDbg("dirwh %d\n", opt->dirwh);
+			break;
+		case Opt_rdcache:
+			AuDbg("rdcache %d\n", opt->rdcache);
+			break;
+		case Opt_rdblk:
+			AuDbg("rdblk %u\n", opt->rdblk);
+			break;
+		case Opt_rdblk_def:
+			AuDbg("rdblk_def\n");
+			break;
+		case Opt_rdhash:
+			AuDbg("rdhash %u\n", opt->rdhash);
+			break;
+		case Opt_rdhash_def:
+			AuDbg("rdhash_def\n");
+			break;
+		case Opt_xino:
+			u.xino = &opt->xino;
+			AuDbg("xino {%s %.*s}\n",
+				  u.xino->path,
+				  AuDLNPair(u.xino->file->f_dentry));
+			break;
+		case Opt_trunc_xino:
+			AuLabel(trunc_xino);
+			break;
+		case Opt_notrunc_xino:
+			AuLabel(notrunc_xino);
+			break;
+		case Opt_trunc_xino_path:
+		case Opt_itrunc_xino:
+			u.xino_itrunc = &opt->xino_itrunc;
+			AuDbg("trunc_xino %d\n", u.xino_itrunc->bindex);
+			break;
+
+		case Opt_noxino:
+			AuLabel(noxino);
+			break;
+		case Opt_trunc_xib:
+			AuLabel(trunc_xib);
+			break;
+		case Opt_notrunc_xib:
+			AuLabel(notrunc_xib);
+			break;
+		case Opt_shwh:
+			AuLabel(shwh);
+			break;
+		case Opt_noshwh:
+			AuLabel(noshwh);
+			break;
+		case Opt_plink:
+			AuLabel(plink);
+			break;
+		case Opt_noplink:
+			AuLabel(noplink);
+			break;
+		case Opt_list_plink:
+			AuLabel(list_plink);
+			break;
+		case Opt_udba:
+			AuDbg("udba %d, %s\n",
+				  opt->udba, au_optstr_udba(opt->udba));
+			break;
+		case Opt_diropq_a:
+			AuLabel(diropq_a);
+			break;
+		case Opt_diropq_w:
+			AuLabel(diropq_w);
+			break;
+		case Opt_warn_perm:
+			AuLabel(warn_perm);
+			break;
+		case Opt_nowarn_perm:
+			AuLabel(nowarn_perm);
+			break;
+		case Opt_refrof:
+			AuLabel(refrof);
+			break;
+		case Opt_norefrof:
+			AuLabel(norefrof);
+			break;
+		case Opt_verbose:
+			AuLabel(verbose);
+			break;
+		case Opt_noverbose:
+			AuLabel(noverbose);
+			break;
+		case Opt_sum:
+			AuLabel(sum);
+			break;
+		case Opt_nosum:
+			AuLabel(nosum);
+			break;
+		case Opt_wsum:
+			AuLabel(wsum);
+			break;
+		case Opt_wbr_create:
+			u.create = &opt->wbr_create;
+			AuDbg("create %d, %s\n", u.create->wbr_create,
+				  au_optstr_wbr_create(u.create->wbr_create));
+			switch (u.create->wbr_create) {
+			case AuWbrCreate_MFSV:
+			case AuWbrCreate_PMFSV:
+				AuDbg("%d sec\n", u.create->mfs_second);
+				break;
+			case AuWbrCreate_MFSRR:
+				AuDbg("%llu watermark\n",
+					  u.create->mfsrr_watermark);
+				break;
+			case AuWbrCreate_MFSRRV:
+				AuDbg("%llu watermark, %d sec\n",
+					  u.create->mfsrr_watermark,
+					  u.create->mfs_second);
+				break;
+			}
+			break;
+		case Opt_wbr_copyup:
+			AuDbg("copyup %d, %s\n", opt->wbr_copyup,
+				  au_optstr_wbr_copyup(opt->wbr_copyup));
+			break;
+		default:
+			BUG();
+		}
+		opt++;
+	}
+#endif
+}
+
+void au_opts_free(struct au_opts *opts)
+{
+	struct au_opt *opt;
+
+	opt = opts->opt;
+	while (opt->type != Opt_tail) {
+		switch (opt->type) {
+		case Opt_add:
+		case Opt_append:
+		case Opt_prepend:
+			path_put(&opt->add.path);
+			break;
+		case Opt_del:
+		case Opt_idel:
+			path_put(&opt->del.h_path);
+			break;
+		case Opt_mod:
+		case Opt_imod:
+			dput(opt->mod.h_root);
+			break;
+		case Opt_xino:
+			fput(opt->xino.file);
+			break;
+		}
+		opt++;
+	}
+}
+
+static int opt_add(struct au_opt *opt, char *opt_str, unsigned long sb_flags,
+		   aufs_bindex_t bindex)
+{
+	int err;
+	struct au_opt_add *add = &opt->add;
+	char *p;
+
+	add->bindex = bindex;
+	add->perm = AuBrPerm_Last;
+	add->pathname = opt_str;
+	p = strchr(opt_str, '=');
+	if (p) {
+		*p++ = 0;
+		if (*p)
+			add->perm = br_perm_val(p);
+	}
+
+	err = vfsub_kern_path(add->pathname, lkup_dirflags, &add->path);
+	if (!err) {
+		if (!p) {
+			add->perm = AuBrPerm_RO;
+			if (au_test_fs_rr(add->path.dentry->d_sb))
+				add->perm = AuBrPerm_RR;
+			else if (!bindex && !(sb_flags & MS_RDONLY))
+				add->perm = AuBrPerm_RW;
+		}
+		opt->type = Opt_add;
+		goto out;
+	}
+	AuErr("lookup failed %s (%d)\n", add->pathname, err);
+	err = -EINVAL;
+
+ out:
+	return err;
+}
+
+static int au_opts_parse_del(struct au_opt_del *del, substring_t args[])
+{
+	int err;
+
+	del->pathname = args[0].from;
+	AuDbg("del path %s\n", del->pathname);
+
+	err = vfsub_kern_path(del->pathname, lkup_dirflags, &del->h_path);
+	if (unlikely(err))
+		AuErr("lookup failed %s (%d)\n", del->pathname, err);
+
+	return err;
+}
+
+#if 0 /* reserved for future use */
+static int au_opts_parse_idel(struct super_block *sb, aufs_bindex_t bindex,
+			      struct au_opt_del *del, substring_t args[])
+{
+	int err;
+	struct dentry *root;
+
+	err = -EINVAL;
+	root = sb->s_root;
+	aufs_read_lock(root, AuLock_FLUSH);
+	if (bindex < 0 || au_sbend(sb) < bindex) {
+		AuErr("out of bounds, %d\n", bindex);
+		goto out;
+	}
+
+	err = 0;
+	del->h_path.dentry = dget(au_h_dptr(root, bindex));
+	del->h_path.mnt = mntget(au_sbr_mnt(sb, bindex));
+
+ out:
+	aufs_read_unlock(root, !AuLock_IR);
+	return err;
+}
+#endif
+
+static int au_opts_parse_mod(struct au_opt_mod *mod, substring_t args[])
+{
+	int err;
+	struct path path;
+	char *p;
+
+	err = -EINVAL;
+	mod->path = args[0].from;
+	p = strchr(mod->path, '=');
+	if (unlikely(!p)) {
+		AuErr("no permssion %s\n", args[0].from);
+		goto out;
+	}
+
+	*p++ = 0;
+	err = vfsub_kern_path(mod->path, lkup_dirflags, &path);
+	if (unlikely(err)) {
+		AuErr("lookup failed %s (%d)\n", mod->path, err);
+		goto out;
+	}
+
+	mod->perm = br_perm_val(p);
+	AuDbg("mod path %s, perm 0x%x, %s\n", mod->path, mod->perm, p);
+	mod->h_root = dget(path.dentry);
+	path_put(&path);
+
+ out:
+	return err;
+}
+
+#if 0 /* reserved for future use */
+static int au_opts_parse_imod(struct super_block *sb, aufs_bindex_t bindex,
+			      struct au_opt_mod *mod, substring_t args[])
+{
+	int err;
+	struct dentry *root;
+
+	err = -EINVAL;
+	root = sb->s_root;
+	aufs_read_lock(root, AuLock_FLUSH);
+	if (bindex < 0 || au_sbend(sb) < bindex) {
+		AuErr("out of bounds, %d\n", bindex);
+		goto out;
+	}
+
+	err = 0;
+	mod->perm = br_perm_val(args[1].from);
+	AuDbg("mod path %s, perm 0x%x, %s\n",
+	      mod->path, mod->perm, args[1].from);
+	mod->h_root = dget(au_h_dptr(root, bindex));
+
+ out:
+	aufs_read_unlock(root, !AuLock_IR);
+	return err;
+}
+#endif
+
+static int au_opts_parse_xino(struct super_block *sb, struct au_opt_xino *xino,
+			      substring_t args[])
+{
+	int err;
+	struct file *file;
+
+	file = au_xino_create(sb, args[0].from, /*silent*/0);
+	err = PTR_ERR(file);
+	if (IS_ERR(file))
+		goto out;
+
+	err = -EINVAL;
+	if (unlikely(file->f_dentry->d_sb == sb)) {
+		fput(file);
+		AuErr("%s must be outside\n", args[0].from);
+		goto out;
+	}
+
+	err = 0;
+	xino->file = file;
+	xino->path = args[0].from;
+
+ out:
+	return err;
+}
+
+static
+int au_opts_parse_xino_itrunc_path(struct super_block *sb,
+				   struct au_opt_xino_itrunc *xino_itrunc,
+				   substring_t args[])
+{
+	int err;
+	aufs_bindex_t bend, bindex;
+	struct path path;
+	struct dentry *root;
+
+	err = vfsub_kern_path(args[0].from, lkup_dirflags, &path);
+	if (unlikely(err)) {
+		AuErr("lookup failed %s (%d)\n", args[0].from, err);
+		goto out;
+	}
+
+	xino_itrunc->bindex = -1;
+	root = sb->s_root;
+	aufs_read_lock(root, AuLock_FLUSH);
+	bend = au_sbend(sb);
+	for (bindex = 0; bindex <= bend; bindex++) {
+		if (au_h_dptr(root, bindex) == path.dentry) {
+			xino_itrunc->bindex = bindex;
+			break;
+		}
+	}
+	aufs_read_unlock(root, !AuLock_IR);
+	path_put(&path);
+
+	if (unlikely(xino_itrunc->bindex < 0)) {
+		AuErr("no such branch %s\n", args[0].from);
+		err = -EINVAL;
+	}
+
+ out:
+	return err;
+}
+
+/* called without aufs lock */
+int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts)
+{
+	int err, n, token;
+	aufs_bindex_t bindex;
+	unsigned char skipped;
+	struct dentry *root;
+	struct au_opt *opt, *opt_tail;
+	char *opt_str;
+	/* reduce the stack space */
+	union {
+		struct au_opt_xino_itrunc *xino_itrunc;
+		struct au_opt_wbr_create *create;
+	} u;
+	struct {
+		substring_t args[MAX_OPT_ARGS];
+	} *a;
+
+	err = -ENOMEM;
+	a = kmalloc(sizeof(*a), GFP_NOFS);
+	if (unlikely(!a))
+		goto out;
+
+	root = sb->s_root;
+	err = 0;
+	bindex = 0;
+	opt = opts->opt;
+	opt_tail = opt + opts->max_opt - 1;
+	opt->type = Opt_tail;
+	while (!err && (opt_str = strsep(&str, ",")) && *opt_str) {
+		err = -EINVAL;
+		skipped = 0;
+		token = match_token(opt_str, options, a->args);
+		switch (token) {
+		case Opt_br:
+			err = 0;
+			while (!err && (opt_str = strsep(&a->args[0].from, ":"))
+			       && *opt_str) {
+				err = opt_add(opt, opt_str, opts->sb_flags,
+					      bindex++);
+				if (unlikely(!err && ++opt > opt_tail)) {
+					err = -E2BIG;
+					break;
+				}
+				opt->type = Opt_tail;
+				skipped = 1;
+			}
+			break;
+		case Opt_add:
+			if (unlikely(match_int(&a->args[0], &n))) {
+				AuErr("bad integer in %s\n", opt_str);
+				break;
+			}
+			bindex = n;
+			err = opt_add(opt, a->args[1].from, opts->sb_flags,
+				      bindex);
+			if (!err)
+				opt->type = token;
+			break;
+		case Opt_append:
+			err = opt_add(opt, a->args[0].from, opts->sb_flags,
+				      /*dummy bindex*/1);
+			if (!err)
+				opt->type = token;
+			break;
+		case Opt_prepend:
+			err = opt_add(opt, a->args[0].from, opts->sb_flags,
+				      /*bindex*/0);
+			if (!err)
+				opt->type = token;
+			break;
+		case Opt_del:
+			err = au_opts_parse_del(&opt->del, a->args);
+			if (!err)
+				opt->type = token;
+			break;
+#if 0 /* reserved for future use */
+		case Opt_idel:
+			del->pathname = "(indexed)";
+			if (unlikely(match_int(&args[0], &n))) {
+				AuErr("bad integer in %s\n", opt_str);
+				break;
+			}
+			err = au_opts_parse_idel(sb, n, &opt->del, a->args);
+			if (!err)
+				opt->type = token;
+			break;
+#endif
+		case Opt_mod:
+			err = au_opts_parse_mod(&opt->mod, a->args);
+			if (!err)
+				opt->type = token;
+			break;
+#ifdef IMOD /* reserved for future use */
+		case Opt_imod:
+			u.mod->path = "(indexed)";
+			if (unlikely(match_int(&a->args[0], &n))) {
+				AuErr("bad integer in %s\n", opt_str);
+				break;
+			}
+			err = au_opts_parse_imod(sb, n, &opt->mod, a->args);
+			if (!err)
+				opt->type = token;
+			break;
+#endif
+		case Opt_xino:
+			err = au_opts_parse_xino(sb, &opt->xino, a->args);
+			if (!err)
+				opt->type = token;
+			break;
+
+		case Opt_trunc_xino_path:
+			err = au_opts_parse_xino_itrunc_path
+				(sb, &opt->xino_itrunc, a->args);
+			if (!err)
+				opt->type = token;
+			break;
+
+		case Opt_itrunc_xino:
+			u.xino_itrunc = &opt->xino_itrunc;
+			if (unlikely(match_int(&a->args[0], &n))) {
+				AuErr("bad integer in %s\n", opt_str);
+				break;
+			}
+			u.xino_itrunc->bindex = n;
+			aufs_read_lock(root, AuLock_FLUSH);
+			if (n < 0 || au_sbend(sb) < n) {
+				AuErr("out of bounds, %d\n", n);
+				aufs_read_unlock(root, !AuLock_IR);
+				break;
+			}
+			aufs_read_unlock(root, !AuLock_IR);
+			err = 0;
+			opt->type = token;
+			break;
+
+		case Opt_dirwh:
+			if (unlikely(match_int(&a->args[0], &opt->dirwh)))
+				break;
+			err = 0;
+			opt->type = token;
+			break;
+
+		case Opt_rdcache:
+			if (unlikely(match_int(&a->args[0], &opt->rdcache)))
+				break;
+			err = 0;
+			opt->type = token;
+			break;
+		case Opt_rdblk:
+			if (unlikely(match_int(&a->args[0], &n)
+				     || n <= 0
+				     || n > KMALLOC_MAX_SIZE)) {
+				AuErr("bad integer in %s\n", opt_str);
+				break;
+			}
+			if (unlikely(n < NAME_MAX)) {
+				AuErr("rdblk must be larger than %d\n",
+				      NAME_MAX);
+				break;
+			}
+			opt->rdblk = n;
+			err = 0;
+			opt->type = token;
+			break;
+		case Opt_rdhash:
+			if (unlikely(match_int(&a->args[0], &n)
+				     || n <= 0
+				     || n * sizeof(struct hlist_head)
+				     > KMALLOC_MAX_SIZE)) {
+				AuErr("bad integer in %s\n", opt_str);
+				break;
+			}
+			opt->rdhash = n;
+			err = 0;
+			opt->type = token;
+			break;
+
+		case Opt_trunc_xino:
+		case Opt_notrunc_xino:
+		case Opt_noxino:
+		case Opt_trunc_xib:
+		case Opt_notrunc_xib:
+		case Opt_shwh:
+		case Opt_noshwh:
+		case Opt_plink:
+		case Opt_noplink:
+		case Opt_list_plink:
+		case Opt_diropq_a:
+		case Opt_diropq_w:
+		case Opt_warn_perm:
+		case Opt_nowarn_perm:
+		case Opt_refrof:
+		case Opt_norefrof:
+		case Opt_verbose:
+		case Opt_noverbose:
+		case Opt_sum:
+		case Opt_nosum:
+		case Opt_wsum:
+		case Opt_rdblk_def:
+		case Opt_rdhash_def:
+			err = 0;
+			opt->type = token;
+			break;
+
+		case Opt_udba:
+			opt->udba = udba_val(a->args[0].from);
+			if (opt->udba >= 0) {
+				err = 0;
+				opt->type = token;
+			} else
+				AuErr("wrong value, %s\n", opt_str);
+			break;
+
+		case Opt_wbr_create:
+			u.create = &opt->wbr_create;
+			u.create->wbr_create
+				= au_wbr_create_val(a->args[0].from, u.create);
+			if (u.create->wbr_create >= 0) {
+				err = 0;
+				opt->type = token;
+			} else
+				AuErr("wrong value, %s\n", opt_str);
+			break;
+		case Opt_wbr_copyup:
+			opt->wbr_copyup = au_wbr_copyup_val(a->args[0].from);
+			if (opt->wbr_copyup >= 0) {
+				err = 0;
+				opt->type = token;
+			} else
+				AuErr("wrong value, %s\n", opt_str);
+			break;
+
+		case Opt_ignore:
+			AuWarn("ignored %s\n", opt_str);
+			/*FALLTHROUGH*/
+		case Opt_ignore_silent:
+			skipped = 1;
+			err = 0;
+			break;
+		case Opt_err:
+			AuErr("unknown option %s\n", opt_str);
+			break;
+		}
+
+		if (!err && !skipped) {
+			if (unlikely(++opt > opt_tail)) {
+				err = -E2BIG;
+				opt--;
+				opt->type = Opt_tail;
+				break;
+			}
+			opt->type = Opt_tail;
+		}
+	}
+
+	kfree(a);
+	dump_opts(opts);
+	if (unlikely(err))
+		au_opts_free(opts);
+
+ out:
+	return err;
+}
+
+static int au_opt_wbr_create(struct super_block *sb,
+			     struct au_opt_wbr_create *create)
+{
+	int err;
+	struct au_sbinfo *sbinfo;
+
+	SiMustWriteLock(sb);
+
+	err = 1; /* handled */
+	sbinfo = au_sbi(sb);
+	if (sbinfo->si_wbr_create_ops->fin) {
+		err = sbinfo->si_wbr_create_ops->fin(sb);
+		if (!err)
+			err = 1;
+	}
+
+	sbinfo->si_wbr_create = create->wbr_create;
+	sbinfo->si_wbr_create_ops = au_wbr_create_ops + create->wbr_create;
+	switch (create->wbr_create) {
+	case AuWbrCreate_MFSRRV:
+	case AuWbrCreate_MFSRR:
+		sbinfo->si_wbr_mfs.mfsrr_watermark = create->mfsrr_watermark;
+		/*FALLTHROUGH*/
+	case AuWbrCreate_MFS:
+	case AuWbrCreate_MFSV:
+	case AuWbrCreate_PMFS:
+	case AuWbrCreate_PMFSV:
+		sbinfo->si_wbr_mfs.mfs_expire = create->mfs_second * HZ;
+		break;
+	}
+
+	if (sbinfo->si_wbr_create_ops->init)
+		sbinfo->si_wbr_create_ops->init(sb); /* ignore */
+
+	return err;
+}
+
+/*
+ * returns,
+ * plus: processed without an error
+ * zero: unprocessed
+ */
+static int au_opt_simple(struct super_block *sb, struct au_opt *opt,
+			 struct au_opts *opts)
+{
+	int err;
+	struct au_sbinfo *sbinfo;
+
+	SiMustWriteLock(sb);
+
+	err = 1; /* handled */
+	sbinfo = au_sbi(sb);
+	switch (opt->type) {
+	case Opt_udba:
+		sbinfo->si_mntflags &= ~AuOptMask_UDBA;
+		sbinfo->si_mntflags |= opt->udba;
+		opts->given_udba |= opt->udba;
+		break;
+
+	case Opt_plink:
+		au_opt_set(sbinfo->si_mntflags, PLINK);
+		break;
+	case Opt_noplink:
+		if (au_opt_test(sbinfo->si_mntflags, PLINK))
+			au_plink_put(sb);
+		au_opt_clr(sbinfo->si_mntflags, PLINK);
+		break;
+	case Opt_list_plink:
+		if (au_opt_test(sbinfo->si_mntflags, PLINK))
+			au_plink_list(sb);
+		break;
+
+	case Opt_diropq_a:
+		au_opt_set(sbinfo->si_mntflags, ALWAYS_DIROPQ);
+		break;
+	case Opt_diropq_w:
+		au_opt_clr(sbinfo->si_mntflags, ALWAYS_DIROPQ);
+		break;
+
+	case Opt_warn_perm:
+		au_opt_set(sbinfo->si_mntflags, WARN_PERM);
+		break;
+	case Opt_nowarn_perm:
+		au_opt_clr(sbinfo->si_mntflags, WARN_PERM);
+		break;
+
+	case Opt_refrof:
+		au_opt_set(sbinfo->si_mntflags, REFROF);
+		break;
+	case Opt_norefrof:
+		au_opt_clr(sbinfo->si_mntflags, REFROF);
+		break;
+
+	case Opt_verbose:
+		au_opt_set(sbinfo->si_mntflags, VERBOSE);
+		break;
+	case Opt_noverbose:
+		au_opt_clr(sbinfo->si_mntflags, VERBOSE);
+		break;
+
+	case Opt_sum:
+		au_opt_set(sbinfo->si_mntflags, SUM);
+		break;
+	case Opt_wsum:
+		au_opt_clr(sbinfo->si_mntflags, SUM);
+		au_opt_set(sbinfo->si_mntflags, SUM_W);
+	case Opt_nosum:
+		au_opt_clr(sbinfo->si_mntflags, SUM);
+		au_opt_clr(sbinfo->si_mntflags, SUM_W);
+		break;
+
+	case Opt_wbr_create:
+		err = au_opt_wbr_create(sb, &opt->wbr_create);
+		break;
+	case Opt_wbr_copyup:
+		sbinfo->si_wbr_copyup = opt->wbr_copyup;
+		sbinfo->si_wbr_copyup_ops = au_wbr_copyup_ops + opt->wbr_copyup;
+		break;
+
+	case Opt_dirwh:
+		sbinfo->si_dirwh = opt->dirwh;
+		break;
+
+	case Opt_rdcache:
+		sbinfo->si_rdcache = opt->rdcache * HZ;
+		break;
+	case Opt_rdblk:
+		sbinfo->si_rdblk = opt->rdblk;
+		break;
+	case Opt_rdblk_def:
+		sbinfo->si_rdblk = AUFS_RDBLK_DEF;
+		break;
+	case Opt_rdhash:
+		sbinfo->si_rdhash = opt->rdhash;
+		break;
+	case Opt_rdhash_def:
+		sbinfo->si_rdhash = AUFS_RDHASH_DEF;
+		break;
+
+	case Opt_shwh:
+		au_opt_set(sbinfo->si_mntflags, SHWH);
+		break;
+	case Opt_noshwh:
+		au_opt_clr(sbinfo->si_mntflags, SHWH);
+		break;
+
+	case Opt_trunc_xino:
+		au_opt_set(sbinfo->si_mntflags, TRUNC_XINO);
+		break;
+	case Opt_notrunc_xino:
+		au_opt_clr(sbinfo->si_mntflags, TRUNC_XINO);
+		break;
+
+	case Opt_trunc_xino_path:
+	case Opt_itrunc_xino:
+		err = au_xino_trunc(sb, opt->xino_itrunc.bindex);
+		if (!err)
+			err = 1;
+		break;
+
+	case Opt_trunc_xib:
+		au_fset_opts(opts->flags, TRUNC_XIB);
+		break;
+	case Opt_notrunc_xib:
+		au_fclr_opts(opts->flags, TRUNC_XIB);
+		break;
+
+	default:
+		err = 0;
+		break;
+	}
+
+	return err;
+}
+
+/*
+ * returns tri-state.
+ * plus: processed without an error
+ * zero: unprocessed
+ * minus: error
+ */
+static int au_opt_br(struct super_block *sb, struct au_opt *opt,
+		     struct au_opts *opts)
+{
+	int err, do_refresh;
+
+	err = 0;
+	switch (opt->type) {
+	case Opt_append:
+		opt->add.bindex = au_sbend(sb) + 1;
+		if (opt->add.bindex < 0)
+			opt->add.bindex = 0;
+		goto add;
+	case Opt_prepend:
+		opt->add.bindex = 0;
+	add:
+	case Opt_add:
+		err = au_br_add(sb, &opt->add,
+				au_ftest_opts(opts->flags, REMOUNT));
+		if (!err) {
+			err = 1;
+			au_fset_opts(opts->flags, REFRESH_DIR);
+			if (au_br_whable(opt->add.perm))
+				au_fset_opts(opts->flags, REFRESH_NONDIR);
+		}
+		break;
+
+	case Opt_del:
+	case Opt_idel:
+		err = au_br_del(sb, &opt->del,
+				au_ftest_opts(opts->flags, REMOUNT));
+		if (!err) {
+			err = 1;
+			au_fset_opts(opts->flags, TRUNC_XIB);
+			au_fset_opts(opts->flags, REFRESH_DIR);
+			au_fset_opts(opts->flags, REFRESH_NONDIR);
+		}
+		break;
+
+	case Opt_mod:
+	case Opt_imod:
+		err = au_br_mod(sb, &opt->mod,
+				au_ftest_opts(opts->flags, REMOUNT),
+				&do_refresh);
+		if (!err) {
+			err = 1;
+			if (do_refresh) {
+				au_fset_opts(opts->flags, REFRESH_DIR);
+				au_fset_opts(opts->flags, REFRESH_NONDIR);
+			}
+		}
+		break;
+	}
+
+	return err;
+}
+
+static int au_opt_xino(struct super_block *sb, struct au_opt *opt,
+		       struct au_opt_xino **opt_xino,
+		       struct au_opts *opts)
+{
+	int err;
+	aufs_bindex_t bend, bindex;
+	struct dentry *root, *parent, *h_root;
+
+	err = 0;
+	switch (opt->type) {
+	case Opt_xino:
+		err = au_xino_set(sb, &opt->xino,
+				  !!au_ftest_opts(opts->flags, REMOUNT));
+		if (unlikely(err))
+			break;
+
+		*opt_xino = &opt->xino;
+		au_xino_brid_set(sb, -1);
+
+		/* safe d_parent access */
+		parent = opt->xino.file->f_dentry->d_parent;
+		root = sb->s_root;
+		bend = au_sbend(sb);
+		for (bindex = 0; bindex <= bend; bindex++) {
+			h_root = au_h_dptr(root, bindex);
+			if (h_root == parent) {
+				au_xino_brid_set(sb, au_sbr_id(sb, bindex));
+				break;
+			}
+		}
+		break;
+
+	case Opt_noxino:
+		au_xino_clr(sb);
+		au_xino_brid_set(sb, -1);
+		*opt_xino = (void *)-1;
+		break;
+	}
+
+	return err;
+}
+
+int au_opts_verify(struct super_block *sb, unsigned long sb_flags,
+		   unsigned int pending)
+{
+	int err;
+	aufs_bindex_t bindex, bend;
+	unsigned char do_plink, skip, do_free;
+	struct au_branch *br;
+	struct au_wbr *wbr;
+	struct dentry *root;
+	struct inode *dir, *h_dir;
+	struct au_sbinfo *sbinfo;
+	struct au_hinode *hdir;
+
+	SiMustAnyLock(sb);
+
+	sbinfo = au_sbi(sb);
+	AuDebugOn(!(sbinfo->si_mntflags & AuOptMask_UDBA));
+
+	if (!(sb_flags & MS_RDONLY)) {
+		if (unlikely(!au_br_writable(au_sbr_perm(sb, 0))))
+			AuWarn("first branch should be rw\n");
+		if (unlikely(au_opt_test(sbinfo->si_mntflags, SHWH)))
+			AuWarn("shwh should be used with ro\n");
+	}
+
+	if (au_opt_test((sbinfo->si_mntflags | pending), UDBA_HINOTIFY)
+	    && !au_opt_test(sbinfo->si_mntflags, XINO))
+		AuWarn("udba=inotify requires xino\n");
+
+	err = 0;
+	root = sb->s_root;
+	dir = sb->s_root->d_inode;
+	do_plink = !!au_opt_test(sbinfo->si_mntflags, PLINK);
+	bend = au_sbend(sb);
+	for (bindex = 0; !err && bindex <= bend; bindex++) {
+		skip = 0;
+		h_dir = au_h_iptr(dir, bindex);
+		br = au_sbr(sb, bindex);
+		do_free = 0;
+
+		wbr = br->br_wbr;
+		if (wbr)
+			wbr_wh_read_lock(wbr);
+
+		switch (br->br_perm) {
+		case AuBrPerm_RO:
+		case AuBrPerm_ROWH:
+		case AuBrPerm_RR:
+		case AuBrPerm_RRWH:
+			do_free = !!wbr;
+			skip = (!wbr
+				|| (!wbr->wbr_whbase
+				    && !wbr->wbr_plink
+				    && !wbr->wbr_orph));
+			break;
+
+		case AuBrPerm_RWNoLinkWH:
+			/* skip = (!br->br_whbase && !br->br_orph); */
+			skip = (!wbr || !wbr->wbr_whbase);
+			if (skip && wbr) {
+				if (do_plink)
+					skip = !!wbr->wbr_plink;
+				else
+					skip = !wbr->wbr_plink;
+			}
+			break;
+
+		case AuBrPerm_RW:
+			/* skip = (br->br_whbase && br->br_ohph); */
+			skip = (wbr && wbr->wbr_whbase);
+			if (skip) {
+				if (do_plink)
+					skip = !!wbr->wbr_plink;
+				else
+					skip = !wbr->wbr_plink;
+			}
+			break;
+
+		default:
+			BUG();
+		}
+		if (wbr)
+			wbr_wh_read_unlock(wbr);
+
+		if (skip)
+			continue;
+
+		hdir = au_hi(dir, bindex);
+		au_hin_imtx_lock_nested(hdir, AuLsc_I_PARENT);
+		if (wbr)
+			wbr_wh_write_lock(wbr);
+		err = au_wh_init(au_h_dptr(root, bindex), br, sb);
+		if (wbr)
+			wbr_wh_write_unlock(wbr);
+		au_hin_imtx_unlock(hdir);
+
+		if (!err && do_free) {
+			kfree(wbr);
+			br->br_wbr = NULL;
+		}
+	}
+
+	return err;
+}
+
+int au_opts_mount(struct super_block *sb, struct au_opts *opts)
+{
+	int err;
+	unsigned int tmp;
+	aufs_bindex_t bend;
+	struct au_opt *opt;
+	struct au_opt_xino *opt_xino, xino;
+	struct au_sbinfo *sbinfo;
+
+	SiMustWriteLock(sb);
+
+	err = 0;
+	opt_xino = NULL;
+	opt = opts->opt;
+	while (err >= 0 && opt->type != Opt_tail)
+		err = au_opt_simple(sb, opt++, opts);
+	if (err > 0)
+		err = 0;
+	else if (unlikely(err < 0))
+		goto out;
+
+	/* disable xino and udba temporary */
+	sbinfo = au_sbi(sb);
+	tmp = sbinfo->si_mntflags;
+	au_opt_clr(sbinfo->si_mntflags, XINO);
+	au_opt_set_udba(sbinfo->si_mntflags, UDBA_REVAL);
+
+	opt = opts->opt;
+	while (err >= 0 && opt->type != Opt_tail)
+		err = au_opt_br(sb, opt++, opts);
+	if (err > 0)
+		err = 0;
+	else if (unlikely(err < 0))
+		goto out;
+
+	bend = au_sbend(sb);
+	if (unlikely(bend < 0)) {
+		err = -EINVAL;
+		AuErr("no branches\n");
+		goto out;
+	}
+
+	if (au_opt_test(tmp, XINO))
+		au_opt_set(sbinfo->si_mntflags, XINO);
+	opt = opts->opt;
+	while (!err && opt->type != Opt_tail)
+		err = au_opt_xino(sb, opt++, &opt_xino, opts);
+	if (unlikely(err))
+		goto out;
+
+	err = au_opts_verify(sb, sb->s_flags, tmp);
+	if (unlikely(err))
+		goto out;
+
+	/* restore xino */
+	if (au_opt_test(tmp, XINO) && !opt_xino) {
+		xino.file = au_xino_def(sb);
+		err = PTR_ERR(xino.file);
+		if (IS_ERR(xino.file))
+			goto out;
+
+		err = au_xino_set(sb, &xino, /*remount*/0);
+		fput(xino.file);
+		if (unlikely(err))
+			goto out;
+	}
+
+	/* restore udba */
+	sbinfo->si_mntflags &= ~AuOptMask_UDBA;
+	sbinfo->si_mntflags |= (tmp & AuOptMask_UDBA);
+	if (au_opt_test(tmp, UDBA_HINOTIFY)) {
+		struct inode *dir = sb->s_root->d_inode;
+		au_reset_hinotify(dir,
+				  au_hi_flags(dir, /*isdir*/1) & ~AuHi_XINO);
+	}
+
+ out:
+	return err;
+}
+
+int au_opts_remount(struct super_block *sb, struct au_opts *opts)
+{
+	int err, rerr;
+	struct inode *dir;
+	struct au_opt_xino *opt_xino;
+	struct au_opt *opt;
+	struct au_sbinfo *sbinfo;
+
+	SiMustWriteLock(sb);
+
+	dir = sb->s_root->d_inode;
+	sbinfo = au_sbi(sb);
+	err = 0;
+	opt_xino = NULL;
+	opt = opts->opt;
+	while (err >= 0 && opt->type != Opt_tail) {
+		err = au_opt_simple(sb, opt, opts);
+		if (!err)
+			err = au_opt_br(sb, opt, opts);
+		if (!err)
+			err = au_opt_xino(sb, opt, &opt_xino, opts);
+		opt++;
+	}
+	if (err > 0)
+		err = 0;
+	AuTraceErr(err);
+	/* go on even err */
+
+	rerr = au_opts_verify(sb, opts->sb_flags, /*pending*/0);
+	if (unlikely(rerr && !err))
+		err = rerr;
+
+	if (au_ftest_opts(opts->flags, TRUNC_XIB)) {
+		rerr = au_xib_trunc(sb);
+		if (unlikely(rerr && !err))
+			err = rerr;
+	}
+
+	/* will be handled by the caller */
+	if (!au_ftest_opts(opts->flags, REFRESH_DIR)
+	    && (opts->given_udba || au_opt_test(sbinfo->si_mntflags, XINO)))
+		au_fset_opts(opts->flags, REFRESH_DIR);
+
+	AuDbg("status 0x%x\n", opts->flags);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+unsigned int au_opt_udba(struct super_block *sb)
+{
+	return au_mntflags(sb) & AuOptMask_UDBA;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/opts.h linux-2.6.31.4/fs/aufs/opts.h
--- linux-2.6.31.4.orig/fs/aufs/opts.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/opts.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * mount options/flags
+ */
+
+#ifndef __AUFS_OPTS_H__
+#define __AUFS_OPTS_H__
+
+#ifdef __KERNEL__
+
+#include <linux/path.h>
+#include <linux/aufs_type.h>
+
+struct file;
+struct super_block;
+
+/* ---------------------------------------------------------------------- */
+
+/* mount flags */
+#define AuOpt_XINO		1		/* external inode number bitmap
+						   and translation table */
+#define AuOpt_TRUNC_XINO	(1 << 1)	/* truncate xino files */
+#define AuOpt_UDBA_NONE		(1 << 2)	/* users direct branch access */
+#define AuOpt_UDBA_REVAL	(1 << 3)
+#define AuOpt_UDBA_HINOTIFY	(1 << 4)
+#define AuOpt_SHWH		(1 << 5)	/* show whiteout */
+#define AuOpt_PLINK		(1 << 6)	/* pseudo-link */
+#define AuOpt_DIRPERM1		(1 << 7)	/* unimplemented */
+#define AuOpt_REFROF		(1 << 8)	/* unimplemented */
+#define AuOpt_ALWAYS_DIROPQ	(1 << 9)	/* policy to creating diropq */
+#define AuOpt_SUM		(1 << 10)	/* summation for statfs(2) */
+#define AuOpt_SUM_W		(1 << 11)	/* unimplemented */
+#define AuOpt_WARN_PERM		(1 << 12)	/* warn when add-branch */
+#define AuOpt_VERBOSE		(1 << 13)	/* busy inode when del-branch */
+
+#ifndef CONFIG_AUFS_HINOTIFY
+#undef AuOpt_UDBA_HINOTIFY
+#define AuOpt_UDBA_HINOTIFY	0
+#endif
+#ifndef CONFIG_AUFS_SHWH
+#undef AuOpt_SHWH
+#define AuOpt_SHWH		0
+#endif
+
+#define AuOpt_Def	(AuOpt_XINO \
+			 | AuOpt_UDBA_REVAL \
+			 | AuOpt_PLINK \
+			 /* | AuOpt_DIRPERM1 */ \
+			 | AuOpt_WARN_PERM)
+#define AuOptMask_UDBA	(AuOpt_UDBA_NONE \
+			 | AuOpt_UDBA_REVAL \
+			 | AuOpt_UDBA_HINOTIFY)
+
+#define au_opt_test(flags, name)	(flags & AuOpt_##name)
+#define au_opt_set(flags, name) do { \
+	BUILD_BUG_ON(AuOpt_##name & AuOptMask_UDBA); \
+	((flags) |= AuOpt_##name); \
+} while (0)
+#define au_opt_set_udba(flags, name) do { \
+	(flags) &= ~AuOptMask_UDBA; \
+	((flags) |= AuOpt_##name); \
+} while (0)
+#define au_opt_clr(flags, name)		{ ((flags) &= ~AuOpt_##name); }
+
+/* ---------------------------------------------------------------------- */
+
+/* policies to select one among multiple writable branches */
+enum {
+	AuWbrCreate_TDP,	/* top down parent */
+	AuWbrCreate_RR,		/* round robin */
+	AuWbrCreate_MFS,	/* most free space */
+	AuWbrCreate_MFSV,	/* mfs with seconds */
+	AuWbrCreate_MFSRR,	/* mfs then rr */
+	AuWbrCreate_MFSRRV,	/* mfs then rr with seconds */
+	AuWbrCreate_PMFS,	/* parent and mfs */
+	AuWbrCreate_PMFSV,	/* parent and mfs with seconds */
+
+	AuWbrCreate_Def = AuWbrCreate_TDP
+};
+
+enum {
+	AuWbrCopyup_TDP,	/* top down parent */
+	AuWbrCopyup_BUP,	/* bottom up parent */
+	AuWbrCopyup_BU,		/* bottom up */
+
+	AuWbrCopyup_Def = AuWbrCopyup_TDP
+};
+
+/* ---------------------------------------------------------------------- */
+
+struct au_opt_add {
+	aufs_bindex_t	bindex;
+	char		*pathname;
+	int		perm;
+	struct path	path;
+};
+
+struct au_opt_del {
+	char		*pathname;
+	struct path	h_path;
+};
+
+struct au_opt_mod {
+	char		*path;
+	int		perm;
+	struct dentry	*h_root;
+};
+
+struct au_opt_xino {
+	char		*path;
+	struct file	*file;
+};
+
+struct au_opt_xino_itrunc {
+	aufs_bindex_t	bindex;
+};
+
+struct au_opt_wbr_create {
+	int			wbr_create;
+	int			mfs_second;
+	unsigned long long	mfsrr_watermark;
+};
+
+struct au_opt {
+	int type;
+	union {
+		struct au_opt_xino	xino;
+		struct au_opt_xino_itrunc xino_itrunc;
+		struct au_opt_add	add;
+		struct au_opt_del	del;
+		struct au_opt_mod	mod;
+		int			dirwh;
+		int			rdcache;
+		unsigned int		rdblk;
+		unsigned int		rdhash;
+		int			udba;
+		struct au_opt_wbr_create wbr_create;
+		int			wbr_copyup;
+	};
+};
+
+/* opts flags */
+#define AuOpts_REMOUNT		1
+#define AuOpts_REFRESH_DIR	(1 << 1)
+#define AuOpts_REFRESH_NONDIR	(1 << 2)
+#define AuOpts_TRUNC_XIB	(1 << 3)
+#define au_ftest_opts(flags, name)	((flags) & AuOpts_##name)
+#define au_fset_opts(flags, name)	{ (flags) |= AuOpts_##name; }
+#define au_fclr_opts(flags, name)	{ (flags) &= ~AuOpts_##name; }
+
+struct au_opts {
+	struct au_opt	*opt;
+	int		max_opt;
+
+	unsigned int	given_udba;
+	unsigned int	flags;
+	unsigned long	sb_flags;
+};
+
+/* ---------------------------------------------------------------------- */
+
+const char *au_optstr_br_perm(int brperm);
+const char *au_optstr_udba(int udba);
+const char *au_optstr_wbr_copyup(int wbr_copyup);
+const char *au_optstr_wbr_create(int wbr_create);
+
+void au_opts_free(struct au_opts *opts);
+int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts);
+int au_opts_verify(struct super_block *sb, unsigned long sb_flags,
+		   unsigned int pending);
+int au_opts_mount(struct super_block *sb, struct au_opts *opts);
+int au_opts_remount(struct super_block *sb, struct au_opts *opts);
+
+unsigned int au_opt_udba(struct super_block *sb);
+
+/* ---------------------------------------------------------------------- */
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_OPTS_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/plink.c linux-2.6.31.4/fs/aufs/plink.c
--- linux-2.6.31.4.orig/fs/aufs/plink.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/plink.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,354 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * pseudo-link
+ */
+
+#include "aufs.h"
+
+/*
+ * during a user process maintains the pseudo-links,
+ * prohibit adding a new plink and branch manipulation.
+ */
+void au_plink_block_maintain(struct super_block *sb)
+{
+	struct au_sbinfo *sbi = au_sbi(sb);
+
+	SiMustAnyLock(sb);
+
+	/* gave up wake_up_bit() */
+	wait_event(sbi->si_plink_wq, !au_ftest_si(sbi, MAINTAIN_PLINK));
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct pseudo_link {
+	struct list_head list;
+	struct inode *inode;
+};
+
+#ifdef CONFIG_AUFS_DEBUG
+void au_plink_list(struct super_block *sb)
+{
+	struct au_sbinfo *sbinfo;
+	struct list_head *plink_list;
+	struct pseudo_link *plink;
+
+	SiMustAnyLock(sb);
+
+	sbinfo = au_sbi(sb);
+	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+	plink_list = &sbinfo->si_plink.head;
+	spin_lock(&sbinfo->si_plink.spin);
+	list_for_each_entry(plink, plink_list, list)
+		AuDbg("%lu\n", plink->inode->i_ino);
+	spin_unlock(&sbinfo->si_plink.spin);
+}
+#endif
+
+/* is the inode pseudo-linked? */
+int au_plink_test(struct inode *inode)
+{
+	int found;
+	struct au_sbinfo *sbinfo;
+	struct list_head *plink_list;
+	struct pseudo_link *plink;
+
+	sbinfo = au_sbi(inode->i_sb);
+	AuRwMustAnyLock(&sbinfo->si_rwsem);
+	AuDebugOn(!au_opt_test(au_mntflags(inode->i_sb), PLINK));
+
+	found = 0;
+	plink_list = &sbinfo->si_plink.head;
+	spin_lock(&sbinfo->si_plink.spin);
+	list_for_each_entry(plink, plink_list, list)
+		if (plink->inode == inode) {
+			found = 1;
+			break;
+		}
+	spin_unlock(&sbinfo->si_plink.spin);
+	return found;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * generate a name for plink.
+ * the file will be stored under AUFS_WH_PLINKDIR.
+ */
+/* 20 is max digits length of ulong 64 */
+#define PLINK_NAME_LEN	((20 + 1) * 2)
+
+static int plink_name(char *name, int len, struct inode *inode,
+		      aufs_bindex_t bindex)
+{
+	int rlen;
+	struct inode *h_inode;
+
+	h_inode = au_h_iptr(inode, bindex);
+	rlen = snprintf(name, len, "%lu.%lu", inode->i_ino, h_inode->i_ino);
+	return rlen;
+}
+
+/* lookup the plink-ed @inode under the branch at @bindex */
+struct dentry *au_plink_lkup(struct inode *inode, aufs_bindex_t bindex)
+{
+	struct dentry *h_dentry, *h_parent;
+	struct au_branch *br;
+	struct inode *h_dir;
+	char a[PLINK_NAME_LEN];
+	struct qstr tgtname = {
+		.name	= a
+	};
+
+	br = au_sbr(inode->i_sb, bindex);
+	h_parent = br->br_wbr->wbr_plink;
+	h_dir = h_parent->d_inode;
+	tgtname.len = plink_name(a, sizeof(a), inode, bindex);
+
+	/* always superio. */
+	mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_CHILD2);
+	h_dentry = au_sio_lkup_one(&tgtname, h_parent, br);
+	mutex_unlock(&h_dir->i_mutex);
+	return h_dentry;
+}
+
+/* create a pseudo-link */
+static int do_whplink(struct qstr *tgt, struct dentry *h_parent,
+		      struct dentry *h_dentry, struct au_branch *br)
+{
+	int err;
+	struct path h_path = {
+		.mnt = br->br_mnt
+	};
+	struct inode *h_dir;
+
+	h_dir = h_parent->d_inode;
+ again:
+	h_path.dentry = au_lkup_one(tgt, h_parent, br, /*nd*/NULL);
+	err = PTR_ERR(h_path.dentry);
+	if (IS_ERR(h_path.dentry))
+		goto out;
+
+	err = 0;
+	/* wh.plink dir is not monitored */
+	if (h_path.dentry->d_inode
+	    && h_path.dentry->d_inode != h_dentry->d_inode) {
+		err = vfsub_unlink(h_dir, &h_path, /*force*/0);
+		dput(h_path.dentry);
+		h_path.dentry = NULL;
+		if (!err)
+			goto again;
+	}
+	if (!err && !h_path.dentry->d_inode)
+		err = vfsub_link(h_dentry, h_dir, &h_path);
+	dput(h_path.dentry);
+
+ out:
+	return err;
+}
+
+struct do_whplink_args {
+	int *errp;
+	struct qstr *tgt;
+	struct dentry *h_parent;
+	struct dentry *h_dentry;
+	struct au_branch *br;
+};
+
+static void call_do_whplink(void *args)
+{
+	struct do_whplink_args *a = args;
+	*a->errp = do_whplink(a->tgt, a->h_parent, a->h_dentry, a->br);
+}
+
+static int whplink(struct dentry *h_dentry, struct inode *inode,
+		   aufs_bindex_t bindex, struct au_branch *br)
+{
+	int err, wkq_err;
+	struct au_wbr *wbr;
+	struct dentry *h_parent;
+	struct inode *h_dir;
+	char a[PLINK_NAME_LEN];
+	struct qstr tgtname = {
+		.name = a
+	};
+
+	wbr = au_sbr(inode->i_sb, bindex)->br_wbr;
+	h_parent = wbr->wbr_plink;
+	h_dir = h_parent->d_inode;
+	tgtname.len = plink_name(a, sizeof(a), inode, bindex);
+
+	/* always superio. */
+	mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_CHILD2);
+	if (!au_test_wkq(current)) {
+		struct do_whplink_args args = {
+			.errp		= &err,
+			.tgt		= &tgtname,
+			.h_parent	= h_parent,
+			.h_dentry	= h_dentry,
+			.br		= br
+		};
+		wkq_err = au_wkq_wait(call_do_whplink, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	} else
+		err = do_whplink(&tgtname, h_parent, h_dentry, br);
+	mutex_unlock(&h_dir->i_mutex);
+
+	return err;
+}
+
+/* free a single plink */
+static void do_put_plink(struct pseudo_link *plink, int do_del)
+{
+	iput(plink->inode);
+	if (do_del)
+		list_del(&plink->list);
+	kfree(plink);
+}
+
+/*
+ * create a new pseudo-link for @h_dentry on @bindex.
+ * the linked inode is held in aufs @inode.
+ */
+void au_plink_append(struct inode *inode, aufs_bindex_t bindex,
+		     struct dentry *h_dentry)
+{
+	struct super_block *sb;
+	struct au_sbinfo *sbinfo;
+	struct list_head *plink_list;
+	struct pseudo_link *plink;
+	int found, err, cnt;
+
+	sb = inode->i_sb;
+	sbinfo = au_sbi(sb);
+	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+	err = 0;
+	cnt = 0;
+	found = 0;
+	plink_list = &sbinfo->si_plink.head;
+	spin_lock(&sbinfo->si_plink.spin);
+	list_for_each_entry(plink, plink_list, list) {
+		cnt++;
+		if (plink->inode == inode) {
+			found = 1;
+			break;
+		}
+	}
+	if (found) {
+		spin_unlock(&sbinfo->si_plink.spin);
+		return;
+	}
+
+	plink = NULL;
+	if (!found) {
+		plink = kmalloc(sizeof(*plink), GFP_ATOMIC);
+		if (plink) {
+			plink->inode = au_igrab(inode);
+			list_add(&plink->list, plink_list);
+			cnt++;
+		} else
+			err = -ENOMEM;
+	}
+	spin_unlock(&sbinfo->si_plink.spin);
+
+	if (!err) {
+		au_plink_block_maintain(sb);
+		err = whplink(h_dentry, inode, bindex, au_sbr(sb, bindex));
+	}
+
+	if (unlikely(cnt > AUFS_PLINK_WARN))
+		AuWarn1("unexpectedly many pseudo links, %d\n", cnt);
+	if (unlikely(err)) {
+		AuWarn("err %d, damaged pseudo link.\n", err);
+		if (!found && plink)
+			do_put_plink(plink, /*do_del*/1);
+	}
+}
+
+/* free all plinks */
+void au_plink_put(struct super_block *sb)
+{
+	struct au_sbinfo *sbinfo;
+	struct list_head *plink_list;
+	struct pseudo_link *plink, *tmp;
+
+	SiMustWriteLock(sb);
+
+	sbinfo = au_sbi(sb);
+	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+	plink_list = &sbinfo->si_plink.head;
+	/* no spin_lock since sbinfo is write-locked */
+	list_for_each_entry_safe(plink, tmp, plink_list, list)
+		do_put_plink(plink, 0);
+	INIT_LIST_HEAD(plink_list);
+}
+
+/* free the plinks on a branch specified by @br_id */
+void au_plink_half_refresh(struct super_block *sb, aufs_bindex_t br_id)
+{
+	struct au_sbinfo *sbinfo;
+	struct list_head *plink_list;
+	struct pseudo_link *plink, *tmp;
+	struct inode *inode;
+	aufs_bindex_t bstart, bend, bindex;
+	unsigned char do_put;
+
+	SiMustWriteLock(sb);
+
+	sbinfo = au_sbi(sb);
+	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+	plink_list = &sbinfo->si_plink.head;
+	/* no spin_lock since sbinfo is write-locked */
+	list_for_each_entry_safe(plink, tmp, plink_list, list) {
+		do_put = 0;
+		inode = au_igrab(plink->inode);
+		ii_write_lock_child(inode);
+		bstart = au_ibstart(inode);
+		bend = au_ibend(inode);
+		if (bstart >= 0) {
+			for (bindex = bstart; bindex <= bend; bindex++) {
+				if (!au_h_iptr(inode, bindex)
+				    || au_ii_br_id(inode, bindex) != br_id)
+					continue;
+				au_set_h_iptr(inode, bindex, NULL, 0);
+				do_put = 1;
+				break;
+			}
+		} else
+			do_put_plink(plink, 1);
+
+		if (do_put) {
+			for (bindex = bstart; bindex <= bend; bindex++)
+				if (au_h_iptr(inode, bindex)) {
+					do_put = 0;
+					break;
+				}
+			if (do_put)
+				do_put_plink(plink, 1);
+		}
+		ii_write_unlock(inode);
+		iput(inode);
+	}
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/poll.c linux-2.6.31.4/fs/aufs/poll.c
--- linux-2.6.31.4.orig/fs/aufs/poll.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/poll.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * poll operation
+ * There is only one filesystem which implements ->poll operation, currently.
+ */
+
+#include "aufs.h"
+
+unsigned int aufs_poll(struct file *file, poll_table *wait)
+{
+	unsigned int mask;
+	int err;
+	struct file *h_file;
+	struct dentry *dentry;
+	struct super_block *sb;
+
+	/* We should pretend an error happened. */
+	mask = POLLERR /* | POLLIN | POLLOUT */;
+	dentry = file->f_dentry;
+	sb = dentry->d_sb;
+	si_read_lock(sb, AuLock_FLUSH);
+	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
+	if (unlikely(err))
+		goto out;
+
+	/* it is not an error if h_file has no operation */
+	mask = DEFAULT_POLLMASK;
+	h_file = au_h_fptr(file, au_fbstart(file));
+	if (h_file->f_op && h_file->f_op->poll)
+		mask = h_file->f_op->poll(h_file, wait);
+
+	di_read_unlock(dentry, AuLock_IR);
+	fi_read_unlock(file);
+
+ out:
+	si_read_unlock(sb);
+	AuTraceErr((int)mask);
+	return mask;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/rwsem.h linux-2.6.31.4/fs/aufs/rwsem.h
--- linux-2.6.31.4.orig/fs/aufs/rwsem.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/rwsem.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,186 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * simple read-write semaphore wrappers
+ */
+
+#ifndef __AUFS_RWSEM_H__
+#define __AUFS_RWSEM_H__
+
+#ifdef __KERNEL__
+
+#include <linux/rwsem.h>
+
+struct au_rwsem {
+	struct rw_semaphore	rwsem;
+#ifdef CONFIG_AUFS_DEBUG
+	/* just for debugging, not almighty counter */
+	atomic_t		rcnt, wcnt;
+#endif
+};
+
+#ifdef CONFIG_AUFS_DEBUG
+#define AuDbgCntInit(rw) do { \
+	atomic_set(&(rw)->rcnt, 0); \
+	atomic_set(&(rw)->wcnt, 0); \
+	smp_mb(); /* atomic set */ \
+} while (0)
+
+#define AuDbgRcntInc(rw)	atomic_inc_return(&(rw)->rcnt)
+#define AuDbgRcntDec(rw)	WARN_ON(atomic_dec_return(&(rw)->rcnt) < 0)
+#define AuDbgWcntInc(rw)	WARN_ON(atomic_inc_return(&(rw)->wcnt) > 1)
+#define AuDbgWcntDec(rw)	WARN_ON(atomic_dec_return(&(rw)->wcnt) < 0)
+#else
+#define AuDbgCntInit(rw)	do {} while (0)
+#define AuDbgRcntInc(rw)	do {} while (0)
+#define AuDbgRcntDec(rw)	do {} while (0)
+#define AuDbgWcntInc(rw)	do {} while (0)
+#define AuDbgWcntDec(rw)	do {} while (0)
+#endif /* CONFIG_AUFS_DEBUG */
+
+/* to debug easier, do not make them inlined functions */
+#define AuRwMustNoWaiters(rw)	AuDebugOn(!list_empty(&(rw)->rwsem.wait_list))
+/* rwsem_is_locked() is unusable */
+#define AuRwMustReadLock(rw)	AuDebugOn(atomic_read(&(rw)->rcnt) <= 0)
+#define AuRwMustWriteLock(rw)	AuDebugOn(atomic_read(&(rw)->wcnt) <= 0)
+#define AuRwMustAnyLock(rw)	AuDebugOn(atomic_read(&(rw)->rcnt) <= 0 \
+					&& atomic_read(&(rw)->wcnt) <= 0)
+#define AuRwDestroy(rw)		AuDebugOn(atomic_read(&(rw)->rcnt) \
+					|| atomic_read(&(rw)->wcnt))
+
+static inline void au_rw_init(struct au_rwsem *rw)
+{
+	AuDbgCntInit(rw);
+	init_rwsem(&rw->rwsem);
+}
+
+static inline void au_rw_init_wlock(struct au_rwsem *rw)
+{
+	au_rw_init(rw);
+	down_write(&rw->rwsem);
+	AuDbgWcntInc(rw);
+}
+
+static inline void au_rw_init_wlock_nested(struct au_rwsem *rw,
+					   unsigned int lsc)
+{
+	au_rw_init(rw);
+	down_write_nested(&rw->rwsem, lsc);
+	AuDbgWcntInc(rw);
+}
+
+static inline void au_rw_read_lock(struct au_rwsem *rw)
+{
+	down_read(&rw->rwsem);
+	AuDbgRcntInc(rw);
+}
+
+static inline void au_rw_read_lock_nested(struct au_rwsem *rw, unsigned int lsc)
+{
+	down_read_nested(&rw->rwsem, lsc);
+	AuDbgRcntInc(rw);
+}
+
+static inline void au_rw_read_unlock(struct au_rwsem *rw)
+{
+	AuRwMustReadLock(rw);
+	AuDbgRcntDec(rw);
+	up_read(&rw->rwsem);
+}
+
+static inline void au_rw_dgrade_lock(struct au_rwsem *rw)
+{
+	AuRwMustWriteLock(rw);
+	AuDbgRcntInc(rw);
+	AuDbgWcntDec(rw);
+	downgrade_write(&rw->rwsem);
+}
+
+static inline void au_rw_write_lock(struct au_rwsem *rw)
+{
+	down_write(&rw->rwsem);
+	AuDbgWcntInc(rw);
+}
+
+static inline void au_rw_write_lock_nested(struct au_rwsem *rw,
+					   unsigned int lsc)
+{
+	down_write_nested(&rw->rwsem, lsc);
+	AuDbgWcntInc(rw);
+}
+
+static inline void au_rw_write_unlock(struct au_rwsem *rw)
+{
+	AuRwMustWriteLock(rw);
+	AuDbgWcntDec(rw);
+	up_write(&rw->rwsem);
+}
+
+/* why is not _nested version defined */
+static inline int au_rw_read_trylock(struct au_rwsem *rw)
+{
+	int ret = down_read_trylock(&rw->rwsem);
+	if (ret)
+		AuDbgRcntInc(rw);
+	return ret;
+}
+
+static inline int au_rw_write_trylock(struct au_rwsem *rw)
+{
+	int ret = down_write_trylock(&rw->rwsem);
+	if (ret)
+		AuDbgWcntInc(rw);
+	return ret;
+}
+
+#undef AuDbgCntInit
+#undef AuDbgRcntInc
+#undef AuDbgRcntDec
+#undef AuDbgWcntInc
+#undef AuDbgWcntDec
+
+#define AuSimpleLockRwsemFuncs(prefix, param, rwsem) \
+static inline void prefix##_read_lock(param) \
+{ au_rw_read_lock(rwsem); } \
+static inline void prefix##_write_lock(param) \
+{ au_rw_write_lock(rwsem); } \
+static inline int prefix##_read_trylock(param) \
+{ return au_rw_read_trylock(rwsem); } \
+static inline int prefix##_write_trylock(param) \
+{ return au_rw_write_trylock(rwsem); }
+/* why is not _nested version defined */
+/* static inline void prefix##_read_trylock_nested(param, lsc)
+{ au_rw_read_trylock_nested(rwsem, lsc)); }
+static inline void prefix##_write_trylock_nestd(param, lsc)
+{ au_rw_write_trylock_nested(rwsem, lsc); } */
+
+#define AuSimpleUnlockRwsemFuncs(prefix, param, rwsem) \
+static inline void prefix##_read_unlock(param) \
+{ au_rw_read_unlock(rwsem); } \
+static inline void prefix##_write_unlock(param) \
+{ au_rw_write_unlock(rwsem); } \
+static inline void prefix##_downgrade_lock(param) \
+{ au_rw_dgrade_lock(rwsem); }
+
+#define AuSimpleRwsemFuncs(prefix, param, rwsem) \
+	AuSimpleLockRwsemFuncs(prefix, param, rwsem) \
+	AuSimpleUnlockRwsemFuncs(prefix, param, rwsem)
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_RWSEM_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/sbinfo.c linux-2.6.31.4/fs/aufs/sbinfo.c
--- linux-2.6.31.4.orig/fs/aufs/sbinfo.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/sbinfo.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,208 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * superblock private data
+ */
+
+#include "aufs.h"
+
+/*
+ * they are necessary regardless sysfs is disabled.
+ */
+void au_si_free(struct kobject *kobj)
+{
+	struct au_sbinfo *sbinfo;
+	struct super_block *sb;
+
+	sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
+	AuDebugOn(!list_empty(&sbinfo->si_plink.head));
+
+	sb = sbinfo->si_sb;
+	si_write_lock(sb);
+	au_xino_clr(sb);
+	au_br_free(sbinfo);
+	kfree(sbinfo->si_branch);
+	mutex_destroy(&sbinfo->si_xib_mtx);
+	si_write_unlock(sb);
+	AuRwDestroy(&sbinfo->si_rwsem);
+
+	kfree(sbinfo);
+}
+
+int au_si_alloc(struct super_block *sb)
+{
+	int err;
+	struct au_sbinfo *sbinfo;
+
+	err = -ENOMEM;
+	sbinfo = kmalloc(sizeof(*sbinfo), GFP_NOFS);
+	if (unlikely(!sbinfo))
+		goto out;
+
+	/* will be reallocated separately */
+	sbinfo->si_branch = kzalloc(sizeof(*sbinfo->si_branch), GFP_NOFS);
+	if (unlikely(!sbinfo->si_branch))
+		goto out_sbinfo;
+
+	memset(&sbinfo->si_kobj, 0, sizeof(sbinfo->si_kobj));
+	err = sysaufs_si_init(sbinfo);
+	if (unlikely(err))
+		goto out_br;
+
+	au_nwt_init(&sbinfo->si_nowait);
+	au_rw_init_wlock(&sbinfo->si_rwsem);
+	sbinfo->si_generation = 0;
+	sbinfo->au_si_status = 0;
+	sbinfo->si_bend = -1;
+	sbinfo->si_last_br_id = 0;
+
+	sbinfo->si_wbr_copyup = AuWbrCopyup_Def;
+	sbinfo->si_wbr_create = AuWbrCreate_Def;
+	sbinfo->si_wbr_copyup_ops = au_wbr_copyup_ops + AuWbrCopyup_Def;
+	sbinfo->si_wbr_create_ops = au_wbr_create_ops + AuWbrCreate_Def;
+
+	sbinfo->si_mntflags = AuOpt_Def;
+
+	sbinfo->si_xread = NULL;
+	sbinfo->si_xwrite = NULL;
+	sbinfo->si_xib = NULL;
+	mutex_init(&sbinfo->si_xib_mtx);
+	sbinfo->si_xib_buf = NULL;
+	sbinfo->si_xino_brid = -1;
+	/* leave si_xib_last_pindex and si_xib_next_bit */
+
+	sbinfo->si_rdcache = AUFS_RDCACHE_DEF * HZ;
+	sbinfo->si_rdblk = AUFS_RDBLK_DEF;
+	sbinfo->si_rdhash = AUFS_RDHASH_DEF;
+	sbinfo->si_dirwh = AUFS_DIRWH_DEF;
+
+	au_spl_init(&sbinfo->si_plink);
+	init_waitqueue_head(&sbinfo->si_plink_wq);
+
+	/* leave other members for sysaufs and si_mnt. */
+	sbinfo->si_sb = sb;
+	sb->s_fs_info = sbinfo;
+	au_debug_sbinfo_init(sbinfo);
+	return 0; /* success */
+
+ out_br:
+	kfree(sbinfo->si_branch);
+ out_sbinfo:
+	kfree(sbinfo);
+ out:
+	return err;
+}
+
+int au_sbr_realloc(struct au_sbinfo *sbinfo, int nbr)
+{
+	int err, sz;
+	struct au_branch **brp;
+
+	AuRwMustWriteLock(&sbinfo->si_rwsem);
+
+	err = -ENOMEM;
+	sz = sizeof(*brp) * (sbinfo->si_bend + 1);
+	if (unlikely(!sz))
+		sz = sizeof(*brp);
+	brp = au_kzrealloc(sbinfo->si_branch, sz, sizeof(*brp) * nbr, GFP_NOFS);
+	if (brp) {
+		sbinfo->si_branch = brp;
+		err = 0;
+	}
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+unsigned int au_sigen_inc(struct super_block *sb)
+{
+	unsigned int gen;
+
+	SiMustWriteLock(sb);
+
+	gen = ++au_sbi(sb)->si_generation;
+	au_update_digen(sb->s_root);
+	au_update_iigen(sb->s_root->d_inode);
+	sb->s_root->d_inode->i_version++;
+	return gen;
+}
+
+aufs_bindex_t au_new_br_id(struct super_block *sb)
+{
+	aufs_bindex_t br_id;
+	int i;
+	struct au_sbinfo *sbinfo;
+
+	SiMustWriteLock(sb);
+
+	sbinfo = au_sbi(sb);
+	for (i = 0; i <= AUFS_BRANCH_MAX; i++) {
+		br_id = ++sbinfo->si_last_br_id;
+		if (br_id && au_br_index(sb, br_id) < 0)
+			return br_id;
+	}
+
+	return -1;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* dentry and super_block lock. call at entry point */
+void aufs_read_lock(struct dentry *dentry, int flags)
+{
+	si_read_lock(dentry->d_sb, flags);
+	if (au_ftest_lock(flags, DW))
+		di_write_lock_child(dentry);
+	else
+		di_read_lock_child(dentry, flags);
+}
+
+void aufs_read_unlock(struct dentry *dentry, int flags)
+{
+	if (au_ftest_lock(flags, DW))
+		di_write_unlock(dentry);
+	else
+		di_read_unlock(dentry, flags);
+	si_read_unlock(dentry->d_sb);
+}
+
+void aufs_write_lock(struct dentry *dentry)
+{
+	si_write_lock(dentry->d_sb);
+	di_write_lock_child(dentry);
+}
+
+void aufs_write_unlock(struct dentry *dentry)
+{
+	di_write_unlock(dentry);
+	si_write_unlock(dentry->d_sb);
+}
+
+void aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int flags)
+{
+	si_read_lock(d1->d_sb, flags);
+	di_write_lock2_child(d1, d2, au_ftest_lock(flags, DIR));
+}
+
+void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2)
+{
+	di_write_unlock2(d1, d2);
+	si_read_unlock(d1->d_sb);
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/spl.h linux-2.6.31.4/fs/aufs/spl.h
--- linux-2.6.31.4.orig/fs/aufs/spl.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/spl.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * simple list protected by a spinlock
+ */
+
+#ifndef __AUFS_SPL_H__
+#define __AUFS_SPL_H__
+
+#ifdef __KERNEL__
+
+#include <linux/spinlock.h>
+#include <linux/list.h>
+
+struct au_splhead {
+	spinlock_t		spin;
+	struct list_head	head;
+};
+
+static inline void au_spl_init(struct au_splhead *spl)
+{
+	spin_lock_init(&spl->spin);
+	INIT_LIST_HEAD(&spl->head);
+}
+
+static inline void au_spl_add(struct list_head *list, struct au_splhead *spl)
+{
+	spin_lock(&spl->spin);
+	list_add(list, &spl->head);
+	spin_unlock(&spl->spin);
+}
+
+static inline void au_spl_del(struct list_head *list, struct au_splhead *spl)
+{
+	spin_lock(&spl->spin);
+	list_del(list);
+	spin_unlock(&spl->spin);
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_SPL_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/super.c linux-2.6.31.4/fs/aufs/super.c
--- linux-2.6.31.4.orig/fs/aufs/super.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/super.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,874 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * mount and super_block operations
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/statfs.h>
+#include "aufs.h"
+
+/*
+ * super_operations
+ */
+static struct inode *aufs_alloc_inode(struct super_block *sb __maybe_unused)
+{
+	struct au_icntnr *c;
+
+	c = au_cache_alloc_icntnr();
+	if (c) {
+		inode_init_once(&c->vfs_inode);
+		c->vfs_inode.i_version = 1; /* sigen(sb); */
+		c->iinfo.ii_hinode = NULL;
+		return &c->vfs_inode;
+	}
+	return NULL;
+}
+
+static void aufs_destroy_inode(struct inode *inode)
+{
+	au_iinfo_fin(inode);
+	au_cache_free_icntnr(container_of(inode, struct au_icntnr, vfs_inode));
+}
+
+struct inode *au_iget_locked(struct super_block *sb, ino_t ino)
+{
+	struct inode *inode;
+	int err;
+
+	inode = iget_locked(sb, ino);
+	if (unlikely(!inode)) {
+		inode = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+	if (!(inode->i_state & I_NEW))
+		goto out;
+
+	err = au_xigen_new(inode);
+	if (!err)
+		err = au_iinfo_init(inode);
+	if (!err)
+		inode->i_version++;
+	else {
+		iget_failed(inode);
+		inode = ERR_PTR(err);
+	}
+
+ out:
+	/* never return NULL */
+	AuDebugOn(!inode);
+	AuTraceErrPtr(inode);
+	return inode;
+}
+
+/* lock free root dinfo */
+static int au_show_brs(struct seq_file *seq, struct super_block *sb)
+{
+	int err;
+	aufs_bindex_t bindex, bend;
+	struct path path;
+	struct au_hdentry *hd;
+	struct au_branch *br;
+
+	err = 0;
+	bend = au_sbend(sb);
+	hd = au_di(sb->s_root)->di_hdentry;
+	for (bindex = 0; !err && bindex <= bend; bindex++) {
+		br = au_sbr(sb, bindex);
+		path.mnt = br->br_mnt;
+		path.dentry = hd[bindex].hd_dentry;
+		err = au_seq_path(seq, &path);
+		if (err > 0)
+			err = seq_printf(seq, "=%s",
+					 au_optstr_br_perm(br->br_perm));
+		if (!err && bindex != bend)
+			err = seq_putc(seq, ':');
+	}
+
+	return err;
+}
+
+static void au_show_wbr_create(struct seq_file *m, int v,
+			       struct au_sbinfo *sbinfo)
+{
+	const char *pat;
+
+	AuRwMustAnyLock(&sbinfo->si_rwsem);
+
+	seq_printf(m, ",create=");
+	pat = au_optstr_wbr_create(v);
+	switch (v) {
+	case AuWbrCreate_TDP:
+	case AuWbrCreate_RR:
+	case AuWbrCreate_MFS:
+	case AuWbrCreate_PMFS:
+		seq_printf(m, pat);
+		break;
+	case AuWbrCreate_MFSV:
+		seq_printf(m, /*pat*/"mfs:%lu",
+			   sbinfo->si_wbr_mfs.mfs_expire / HZ);
+		break;
+	case AuWbrCreate_PMFSV:
+		seq_printf(m, /*pat*/"pmfs:%lu",
+			   sbinfo->si_wbr_mfs.mfs_expire / HZ);
+		break;
+	case AuWbrCreate_MFSRR:
+		seq_printf(m, /*pat*/"mfsrr:%llu",
+			   sbinfo->si_wbr_mfs.mfsrr_watermark);
+		break;
+	case AuWbrCreate_MFSRRV:
+		seq_printf(m, /*pat*/"mfsrr:%llu:%lu",
+			   sbinfo->si_wbr_mfs.mfsrr_watermark,
+			   sbinfo->si_wbr_mfs.mfs_expire / HZ);
+		break;
+	}
+}
+
+static int au_show_xino(struct seq_file *seq, struct vfsmount *mnt)
+{
+#ifdef CONFIG_SYSFS
+	return 0;
+#else
+	int err;
+	const int len = sizeof(AUFS_XINO_FNAME) - 1;
+	aufs_bindex_t bindex, brid;
+	struct super_block *sb;
+	struct qstr *name;
+	struct file *f;
+	struct dentry *d, *h_root;
+
+	AuRwMustAnyLock(&sbinfo->si_rwsem);
+
+	err = 0;
+	sb = mnt->mnt_sb;
+	f = au_sbi(sb)->si_xib;
+	if (!f)
+		goto out;
+
+	/* stop printing the default xino path on the first writable branch */
+	h_root = NULL;
+	brid = au_xino_brid(sb);
+	if (brid >= 0) {
+		bindex = au_br_index(sb, brid);
+		h_root = au_di(sb->s_root)->di_hdentry[0 + bindex].hd_dentry;
+	}
+	d = f->f_dentry;
+	name = &d->d_name;
+	/* safe ->d_parent because the file is unlinked */
+	if (d->d_parent == h_root
+	    && name->len == len
+	    && !memcmp(name->name, AUFS_XINO_FNAME, len))
+		goto out;
+
+	seq_puts(seq, ",xino=");
+	err = au_xino_path(seq, f);
+
+ out:
+	return err;
+#endif
+}
+
+/* seq_file will re-call me in case of too long string */
+static int aufs_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+	int err, n;
+	unsigned int mnt_flags, v;
+	struct super_block *sb;
+	struct au_sbinfo *sbinfo;
+
+#define AuBool(name, str) do { \
+	v = au_opt_test(mnt_flags, name); \
+	if (v != au_opt_test(AuOpt_Def, name)) \
+		seq_printf(m, ",%s" #str, v ? "" : "no"); \
+} while (0)
+
+#define AuStr(name, str) do { \
+	v = mnt_flags & AuOptMask_##name; \
+	if (v != (AuOpt_Def & AuOptMask_##name)) \
+		seq_printf(m, "," #str "=%s", au_optstr_##str(v)); \
+} while (0)
+
+#define AuUInt(name, str, val) do { \
+	if (val != AUFS_##name##_DEF) \
+		seq_printf(m, "," #str "=%u", val); \
+} while (0)
+
+	/* lock free root dinfo */
+	sb = mnt->mnt_sb;
+	si_noflush_read_lock(sb);
+	sbinfo = au_sbi(sb);
+	seq_printf(m, ",si=%lx", sysaufs_si_id(sbinfo));
+
+	mnt_flags = au_mntflags(sb);
+	if (au_opt_test(mnt_flags, XINO)) {
+		err = au_show_xino(m, mnt);
+		if (unlikely(err))
+			goto out;
+	} else
+		seq_puts(m, ",noxino");
+
+	AuBool(TRUNC_XINO, trunc_xino);
+	AuStr(UDBA, udba);
+	AuBool(SHWH, shwh);
+	AuBool(PLINK, plink);
+	/* AuBool(DIRPERM1, dirperm1); */
+	/* AuBool(REFROF, refrof); */
+
+	v = sbinfo->si_wbr_create;
+	if (v != AuWbrCreate_Def)
+		au_show_wbr_create(m, v, sbinfo);
+
+	v = sbinfo->si_wbr_copyup;
+	if (v != AuWbrCopyup_Def)
+		seq_printf(m, ",cpup=%s", au_optstr_wbr_copyup(v));
+
+	v = au_opt_test(mnt_flags, ALWAYS_DIROPQ);
+	if (v != au_opt_test(AuOpt_Def, ALWAYS_DIROPQ))
+		seq_printf(m, ",diropq=%c", v ? 'a' : 'w');
+
+	AuUInt(DIRWH, dirwh, sbinfo->si_dirwh);
+
+	n = sbinfo->si_rdcache / HZ;
+	AuUInt(RDCACHE, rdcache, n);
+
+	AuUInt(RDBLK, rdblk, sbinfo->si_rdblk);
+	AuUInt(RDHASH, rdhash, sbinfo->si_rdhash);
+
+	AuBool(SUM, sum);
+	/* AuBool(SUM_W, wsum); */
+	AuBool(WARN_PERM, warn_perm);
+	AuBool(VERBOSE, verbose);
+
+ out:
+	/* be sure to print "br:" last */
+	if (!sysaufs_brs) {
+		seq_puts(m, ",br:");
+		au_show_brs(m, sb);
+	}
+	si_read_unlock(sb);
+	return 0;
+
+#undef Deleted
+#undef AuBool
+#undef AuStr
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* sum mode which returns the summation for statfs(2) */
+
+static u64 au_add_till_max(u64 a, u64 b)
+{
+	u64 old;
+
+	old = a;
+	a += b;
+	if (old < a)
+		return a;
+	return ULLONG_MAX;
+}
+
+static int au_statfs_sum(struct super_block *sb, struct kstatfs *buf)
+{
+	int err;
+	u64 blocks, bfree, bavail, files, ffree;
+	aufs_bindex_t bend, bindex, i;
+	unsigned char shared;
+	struct vfsmount *h_mnt;
+	struct super_block *h_sb;
+
+	blocks = 0;
+	bfree = 0;
+	bavail = 0;
+	files = 0;
+	ffree = 0;
+
+	err = 0;
+	bend = au_sbend(sb);
+	for (bindex = bend; bindex >= 0; bindex--) {
+		h_mnt = au_sbr_mnt(sb, bindex);
+		h_sb = h_mnt->mnt_sb;
+		shared = 0;
+		for (i = bindex + 1; !shared && i <= bend; i++)
+			shared = (au_sbr_sb(sb, i) == h_sb);
+		if (shared)
+			continue;
+
+		/* sb->s_root for NFS is unreliable */
+		err = vfs_statfs(h_mnt->mnt_root, buf);
+		if (unlikely(err))
+			goto out;
+
+		blocks = au_add_till_max(blocks, buf->f_blocks);
+		bfree = au_add_till_max(bfree, buf->f_bfree);
+		bavail = au_add_till_max(bavail, buf->f_bavail);
+		files = au_add_till_max(files, buf->f_files);
+		ffree = au_add_till_max(ffree, buf->f_ffree);
+	}
+
+	buf->f_blocks = blocks;
+	buf->f_bfree = bfree;
+	buf->f_bavail = bavail;
+	buf->f_files = files;
+	buf->f_ffree = ffree;
+
+ out:
+	return err;
+}
+
+static int aufs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	int err;
+	struct super_block *sb;
+
+	/* lock free root dinfo */
+	sb = dentry->d_sb;
+	si_noflush_read_lock(sb);
+	if (!au_opt_test(au_mntflags(sb), SUM))
+		/* sb->s_root for NFS is unreliable */
+		err = vfs_statfs(au_sbr_mnt(sb, 0)->mnt_root, buf);
+	else
+		err = au_statfs_sum(sb, buf);
+	si_read_unlock(sb);
+
+	if (!err) {
+		buf->f_type = AUFS_SUPER_MAGIC;
+		buf->f_namelen -= AUFS_WH_PFX_LEN;
+		memset(&buf->f_fsid, 0, sizeof(buf->f_fsid));
+	}
+	/* buf->f_bsize = buf->f_blocks = buf->f_bfree = buf->f_bavail = -1; */
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* try flushing the lower fs at aufs remount/unmount time */
+
+static void au_fsync_br(struct super_block *sb)
+{
+	aufs_bindex_t bend, bindex;
+	int brperm;
+	struct au_branch *br;
+	struct super_block *h_sb;
+
+	bend = au_sbend(sb);
+	for (bindex = 0; bindex < bend; bindex++) {
+		br = au_sbr(sb, bindex);
+		brperm = br->br_perm;
+		if (brperm == AuBrPerm_RR || brperm == AuBrPerm_RRWH)
+			continue;
+		h_sb = br->br_mnt->mnt_sb;
+		if (bdev_read_only(h_sb->s_bdev))
+			continue;
+
+		lockdep_off();
+		down_write(&h_sb->s_umount);
+		shrink_dcache_sb(h_sb);
+		fsync_super(h_sb);
+		up_write(&h_sb->s_umount);
+		lockdep_on();
+	}
+}
+
+/*
+ * this IS NOT for super_operations.
+ * I guess it will be reverted someday.
+ */
+static void aufs_umount_begin(struct super_block *sb)
+{
+	struct au_sbinfo *sbinfo;
+
+	sbinfo = au_sbi(sb);
+	if (!sbinfo)
+		return;
+
+	si_write_lock(sb);
+	au_fsync_br(sb);
+	if (au_opt_test(au_mntflags(sb), PLINK))
+		au_plink_put(sb);
+	if (sbinfo->si_wbr_create_ops->fin)
+		sbinfo->si_wbr_create_ops->fin(sb);
+	si_write_unlock(sb);
+}
+
+/* final actions when unmounting a file system */
+static void aufs_put_super(struct super_block *sb)
+{
+	struct au_sbinfo *sbinfo;
+
+	sbinfo = au_sbi(sb);
+	if (!sbinfo)
+		return;
+
+	aufs_umount_begin(sb);
+	dbgaufs_si_fin(sbinfo);
+	kobject_put(&sbinfo->si_kobj);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * refresh dentry and inode at remount time.
+ */
+static int do_refresh(struct dentry *dentry, mode_t type,
+		      unsigned int dir_flags)
+{
+	int err;
+	struct dentry *parent;
+
+	di_write_lock_child(dentry);
+	parent = dget_parent(dentry);
+	di_read_lock_parent(parent, AuLock_IR);
+
+	/* returns the number of positive dentries */
+	err = au_refresh_hdentry(dentry, type);
+	if (err >= 0) {
+		struct inode *inode = dentry->d_inode;
+		err = au_refresh_hinode(inode, dentry);
+		if (!err && type == S_IFDIR)
+			au_reset_hinotify(inode, dir_flags);
+	}
+	if (unlikely(err))
+		AuErr("unrecoverable error %d, %.*s\n", err, AuDLNPair(dentry));
+
+	di_read_unlock(parent, AuLock_IR);
+	dput(parent);
+	di_write_unlock(dentry);
+
+	return err;
+}
+
+static int test_dir(struct dentry *dentry, void *arg __maybe_unused)
+{
+	return S_ISDIR(dentry->d_inode->i_mode);
+}
+
+/* gave up consolidating with refresh_nondir() */
+static int refresh_dir(struct dentry *root, unsigned int sigen)
+{
+	int err, i, j, ndentry, e;
+	struct au_dcsub_pages dpages;
+	struct au_dpage *dpage;
+	struct dentry **dentries;
+	struct inode *inode;
+	const unsigned int flags = au_hi_flags(root->d_inode, /*isdir*/1);
+
+	err = 0;
+	list_for_each_entry(inode, &root->d_sb->s_inodes, i_sb_list)
+		if (S_ISDIR(inode->i_mode) && au_iigen(inode) != sigen) {
+			ii_write_lock_child(inode);
+			e = au_refresh_hinode_self(inode, /*do_attr*/1);
+			ii_write_unlock(inode);
+			if (unlikely(e)) {
+				AuDbg("e %d, i%lu\n", e, inode->i_ino);
+				if (!err)
+					err = e;
+				/* go on even if err */
+			}
+		}
+
+	e = au_dpages_init(&dpages, GFP_NOFS);
+	if (unlikely(e)) {
+		if (!err)
+			err = e;
+		goto out;
+	}
+	e = au_dcsub_pages(&dpages, root, test_dir, NULL);
+	if (unlikely(e)) {
+		if (!err)
+			err = e;
+		goto out_dpages;
+	}
+
+	for (i = 0; !e && i < dpages.ndpage; i++) {
+		dpage = dpages.dpages + i;
+		dentries = dpage->dentries;
+		ndentry = dpage->ndentry;
+		for (j = 0; !e && j < ndentry; j++) {
+			struct dentry *d;
+
+			d = dentries[j];
+			au_dbg_verify_dir_parent(d, sigen);
+			if (au_digen(d) != sigen) {
+				e = do_refresh(d, S_IFDIR, flags);
+				if (unlikely(e && !err))
+					err = e;
+				/* break on err */
+			}
+		}
+	}
+
+ out_dpages:
+	au_dpages_free(&dpages);
+ out:
+	return err;
+}
+
+static int test_nondir(struct dentry *dentry, void *arg __maybe_unused)
+{
+	return !S_ISDIR(dentry->d_inode->i_mode);
+}
+
+static int refresh_nondir(struct dentry *root, unsigned int sigen,
+			  int do_dentry)
+{
+	int err, i, j, ndentry, e;
+	struct au_dcsub_pages dpages;
+	struct au_dpage *dpage;
+	struct dentry **dentries;
+	struct inode *inode;
+
+	err = 0;
+	list_for_each_entry(inode, &root->d_sb->s_inodes, i_sb_list)
+		if (!S_ISDIR(inode->i_mode) && au_iigen(inode) != sigen) {
+			ii_write_lock_child(inode);
+			e = au_refresh_hinode_self(inode, /*do_attr*/1);
+			ii_write_unlock(inode);
+			if (unlikely(e)) {
+				AuDbg("e %d, i%lu\n", e, inode->i_ino);
+				if (!err)
+					err = e;
+				/* go on even if err */
+			}
+		}
+
+	if (!do_dentry)
+		goto out;
+
+	e = au_dpages_init(&dpages, GFP_NOFS);
+	if (unlikely(e)) {
+		if (!err)
+			err = e;
+		goto out;
+	}
+	e = au_dcsub_pages(&dpages, root, test_nondir, NULL);
+	if (unlikely(e)) {
+		if (!err)
+			err = e;
+		goto out_dpages;
+	}
+
+	for (i = 0; i < dpages.ndpage; i++) {
+		dpage = dpages.dpages + i;
+		dentries = dpage->dentries;
+		ndentry = dpage->ndentry;
+		for (j = 0; j < ndentry; j++) {
+			struct dentry *d;
+
+			d = dentries[j];
+			au_dbg_verify_nondir_parent(d, sigen);
+			inode = d->d_inode;
+			if (inode && au_digen(d) != sigen) {
+				e = do_refresh(d, inode->i_mode & S_IFMT,
+					       /*dir_flags*/0);
+				if (unlikely(e && !err))
+					err = e;
+				/* go on even err */
+			}
+		}
+	}
+
+ out_dpages:
+	au_dpages_free(&dpages);
+ out:
+	return err;
+}
+
+static void au_remount_refresh(struct super_block *sb, unsigned int flags)
+{
+	int err;
+	unsigned int sigen;
+	struct au_sbinfo *sbinfo;
+	struct dentry *root;
+	struct inode *inode;
+
+	au_sigen_inc(sb);
+	sigen = au_sigen(sb);
+	sbinfo = au_sbi(sb);
+	au_fclr_si(sbinfo, FAILED_REFRESH_DIRS);
+
+	root = sb->s_root;
+	DiMustNoWaiters(root);
+	inode = root->d_inode;
+	IiMustNoWaiters(inode);
+	au_reset_hinotify(inode, au_hi_flags(inode, /*isdir*/1));
+	di_write_unlock(root);
+
+	err = refresh_dir(root, sigen);
+	if (unlikely(err)) {
+		au_fset_si(sbinfo, FAILED_REFRESH_DIRS);
+		AuWarn("Refreshing directories failed, ignored (%d)\n", err);
+	}
+
+	if (au_ftest_opts(flags, REFRESH_NONDIR)) {
+		err = refresh_nondir(root, sigen, !err);
+		if (unlikely(err))
+			AuWarn("Refreshing non-directories failed, ignored"
+			       "(%d)\n", err);
+	}
+
+	/* aufs_write_lock() calls ..._child() */
+	di_write_lock_child(root);
+	au_cpup_attr_all(root->d_inode, /*force*/1);
+}
+
+/* stop extra interpretation of errno in mount(8), and strange error messages */
+static int cvt_err(int err)
+{
+	AuTraceErr(err);
+
+	switch (err) {
+	case -ENOENT:
+	case -ENOTDIR:
+	case -EEXIST:
+	case -EIO:
+		err = -EINVAL;
+	}
+	return err;
+}
+
+static int aufs_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+	int err;
+	struct au_opts opts;
+	struct dentry *root;
+	struct inode *inode;
+	struct au_sbinfo *sbinfo;
+
+	err = 0;
+	root = sb->s_root;
+	if (!data || !*data) {
+		aufs_write_lock(root);
+		err = au_opts_verify(sb, *flags, /*pending*/0);
+		if (!err)
+			au_fsync_br(sb);
+		aufs_write_unlock(root);
+		goto out;
+	}
+
+	err = -ENOMEM;
+	memset(&opts, 0, sizeof(opts));
+	opts.opt = (void *)__get_free_page(GFP_NOFS);
+	if (unlikely(!opts.opt))
+		goto out;
+	opts.max_opt = PAGE_SIZE / sizeof(*opts.opt);
+	opts.flags = AuOpts_REMOUNT;
+	opts.sb_flags = *flags;
+
+	/* parse it before aufs lock */
+	err = au_opts_parse(sb, data, &opts);
+	if (unlikely(err))
+		goto out_opts;
+
+	sbinfo = au_sbi(sb);
+	inode = root->d_inode;
+	mutex_lock(&inode->i_mutex);
+	aufs_write_lock(root);
+	au_fsync_br(sb);
+
+	/* au_opts_remount() may return an error */
+	err = au_opts_remount(sb, &opts);
+	au_opts_free(&opts);
+
+	if (au_ftest_opts(opts.flags, REFRESH_DIR)
+	    || au_ftest_opts(opts.flags, REFRESH_NONDIR))
+		au_remount_refresh(sb, opts.flags);
+
+	aufs_write_unlock(root);
+	mutex_unlock(&inode->i_mutex);
+
+ out_opts:
+	free_page((unsigned long)opts.opt);
+ out:
+	err = cvt_err(err);
+	AuTraceErr(err);
+	return err;
+}
+
+static struct super_operations aufs_sop = {
+	.alloc_inode	= aufs_alloc_inode,
+	.destroy_inode	= aufs_destroy_inode,
+	.drop_inode	= generic_delete_inode,
+	.show_options	= aufs_show_options,
+	.statfs		= aufs_statfs,
+	.put_super	= aufs_put_super,
+	.remount_fs	= aufs_remount_fs
+};
+
+/* ---------------------------------------------------------------------- */
+
+static int alloc_root(struct super_block *sb)
+{
+	int err;
+	struct inode *inode;
+	struct dentry *root;
+
+	err = -ENOMEM;
+	inode = au_iget_locked(sb, AUFS_ROOT_INO);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out;
+
+	inode->i_op = &aufs_dir_iop;
+	inode->i_fop = &aufs_dir_fop;
+	inode->i_mode = S_IFDIR;
+	inode->i_nlink = 2;
+	unlock_new_inode(inode);
+
+	root = d_alloc_root(inode);
+	if (unlikely(!root))
+		goto out_iput;
+	err = PTR_ERR(root);
+	if (IS_ERR(root))
+		goto out_iput;
+
+	err = au_alloc_dinfo(root);
+	if (!err) {
+		sb->s_root = root;
+		return 0; /* success */
+	}
+	dput(root);
+	goto out; /* do not iput */
+
+ out_iput:
+	iget_failed(inode);
+	iput(inode);
+ out:
+	return err;
+
+}
+
+static int aufs_fill_super(struct super_block *sb, void *raw_data,
+			   int silent __maybe_unused)
+{
+	int err;
+	struct au_opts opts;
+	struct dentry *root;
+	struct inode *inode;
+	char *arg = raw_data;
+
+	if (unlikely(!arg || !*arg)) {
+		err = -EINVAL;
+		AuErr("no arg\n");
+		goto out;
+	}
+
+	err = -ENOMEM;
+	memset(&opts, 0, sizeof(opts));
+	opts.opt = (void *)__get_free_page(GFP_NOFS);
+	if (unlikely(!opts.opt))
+		goto out;
+	opts.max_opt = PAGE_SIZE / sizeof(*opts.opt);
+	opts.sb_flags = sb->s_flags;
+
+	err = au_si_alloc(sb);
+	if (unlikely(err))
+		goto out_opts;
+
+	/* all timestamps always follow the ones on the branch */
+	sb->s_flags |= MS_NOATIME | MS_NODIRATIME;
+	sb->s_op = &aufs_sop;
+	sb->s_magic = AUFS_SUPER_MAGIC;
+	sb->s_maxbytes = 0;
+	au_export_init(sb);
+
+	err = alloc_root(sb);
+	if (unlikely(err)) {
+		si_write_unlock(sb);
+		goto out_info;
+	}
+	root = sb->s_root;
+	inode = root->d_inode;
+
+	/*
+	 * actually we can parse options regardless aufs lock here.
+	 * but at remount time, parsing must be done before aufs lock.
+	 * so we follow the same rule.
+	 */
+	ii_write_lock_parent(inode);
+	aufs_write_unlock(root);
+	err = au_opts_parse(sb, arg, &opts);
+	if (unlikely(err))
+		goto out_root;
+
+	/* lock vfs_inode first, then aufs. */
+	mutex_lock(&inode->i_mutex);
+	inode->i_op = &aufs_dir_iop;
+	inode->i_fop = &aufs_dir_fop;
+	aufs_write_lock(root);
+	err = au_opts_mount(sb, &opts);
+	au_opts_free(&opts);
+	if (unlikely(err))
+		goto out_unlock;
+	aufs_write_unlock(root);
+	mutex_unlock(&inode->i_mutex);
+	goto out_opts; /* success */
+
+ out_unlock:
+	aufs_write_unlock(root);
+	mutex_unlock(&inode->i_mutex);
+ out_root:
+	dput(root);
+	sb->s_root = NULL;
+ out_info:
+	kobject_put(&au_sbi(sb)->si_kobj);
+	sb->s_fs_info = NULL;
+ out_opts:
+	free_page((unsigned long)opts.opt);
+ out:
+	AuTraceErr(err);
+	err = cvt_err(err);
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int aufs_get_sb(struct file_system_type *fs_type, int flags,
+		       const char *dev_name __maybe_unused, void *raw_data,
+		       struct vfsmount *mnt)
+{
+	int err;
+	struct super_block *sb;
+
+	/* all timestamps always follow the ones on the branch */
+	/* mnt->mnt_flags |= MNT_NOATIME | MNT_NODIRATIME; */
+	err = get_sb_nodev(fs_type, flags, raw_data, aufs_fill_super, mnt);
+	if (!err) {
+		sb = mnt->mnt_sb;
+		si_write_lock(sb);
+		sysaufs_brs_add(sb, 0);
+		si_write_unlock(sb);
+	}
+	return err;
+}
+
+struct file_system_type aufs_fs_type = {
+	.name		= AUFS_FSTYPE,
+	.fs_flags	=
+		FS_RENAME_DOES_D_MOVE	/* a race between rename and others */
+		| FS_REVAL_DOT,		/* for NFS branch and udba */
+	.get_sb		= aufs_get_sb,
+	.kill_sb	= generic_shutdown_super,
+	/* no need to __module_get() and module_put(). */
+	.owner		= THIS_MODULE,
+};
diff -Nur linux-2.6.31.4.orig/fs/aufs/super.h linux-2.6.31.4/fs/aufs/super.h
--- linux-2.6.31.4.orig/fs/aufs/super.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/super.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,384 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * super_block operations
+ */
+
+#ifndef __AUFS_SUPER_H__
+#define __AUFS_SUPER_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/aufs_type.h>
+#include "rwsem.h"
+#include "spl.h"
+#include "wkq.h"
+
+typedef ssize_t (*au_readf_t)(struct file *, char __user *, size_t, loff_t *);
+typedef ssize_t (*au_writef_t)(struct file *, const char __user *, size_t,
+			       loff_t *);
+
+/* policies to select one among multiple writable branches */
+struct au_wbr_copyup_operations {
+	int (*copyup)(struct dentry *dentry);
+};
+
+struct au_wbr_create_operations {
+	int (*create)(struct dentry *dentry, int isdir);
+	int (*init)(struct super_block *sb);
+	int (*fin)(struct super_block *sb);
+};
+
+struct au_wbr_mfs {
+	struct mutex	mfs_lock; /* protect this structure */
+	unsigned long	mfs_jiffy;
+	unsigned long	mfs_expire;
+	aufs_bindex_t	mfs_bindex;
+
+	unsigned long long	mfsrr_bytes;
+	unsigned long long	mfsrr_watermark;
+};
+
+struct au_branch;
+struct au_sbinfo {
+	/* nowait tasks in the system-wide workqueue */
+	struct au_nowait_tasks	si_nowait;
+
+	struct au_rwsem		si_rwsem;
+
+	/* branch management */
+	unsigned int		si_generation;
+
+	/* see above flags */
+	unsigned char		au_si_status;
+
+	aufs_bindex_t		si_bend;
+	aufs_bindex_t		si_last_br_id;
+	struct au_branch	**si_branch;
+
+	/* policy to select a writable branch */
+	unsigned char		si_wbr_copyup;
+	unsigned char		si_wbr_create;
+	struct au_wbr_copyup_operations *si_wbr_copyup_ops;
+	struct au_wbr_create_operations *si_wbr_create_ops;
+
+	/* round robin */
+	atomic_t		si_wbr_rr_next;
+
+	/* most free space */
+	struct au_wbr_mfs	si_wbr_mfs;
+
+	/* mount flags */
+	/* include/asm-ia64/siginfo.h defines a macro named si_flags */
+	unsigned int		si_mntflags;
+
+	/* external inode number (bitmap and translation table) */
+	au_readf_t		si_xread;
+	au_writef_t		si_xwrite;
+	struct file		*si_xib;
+	struct mutex		si_xib_mtx; /* protect xib members */
+	unsigned long		*si_xib_buf;
+	unsigned long		si_xib_last_pindex;
+	int			si_xib_next_bit;
+	aufs_bindex_t		si_xino_brid;
+	/* reserved for future use */
+	/* unsigned long long	si_xib_limit; */	/* Max xib file size */
+
+#ifdef CONFIG_AUFS_EXPORT
+	/* i_generation */
+	struct file		*si_xigen;
+	atomic_t		si_xigen_next;
+#endif
+
+	/* vdir parameters */
+	unsigned long		si_rdcache;	/* max cache time in HZ */
+	unsigned int		si_rdblk;	/* deblk size */
+	unsigned int		si_rdhash;	/* hash size */
+
+	/*
+	 * If the number of whiteouts are larger than si_dirwh, leave all of
+	 * them after au_whtmp_ren to reduce the cost of rmdir(2).
+	 * future fsck.aufs or kernel thread will remove them later.
+	 * Otherwise, remove all whiteouts and the dir in rmdir(2).
+	 */
+	unsigned int		si_dirwh;
+
+	/*
+	 * rename(2) a directory with all children.
+	 */
+	/* reserved for future use */
+	/* int			si_rendir; */
+
+	/* pseudo_link list */
+	struct au_splhead	si_plink;
+	wait_queue_head_t	si_plink_wq;
+
+	/*
+	 * sysfs and lifetime management.
+	 * this is not a small structure and it may be a waste of memory in case
+	 * of sysfs is disabled, particulary when many aufs-es are mounted.
+	 * but using sysfs is majority.
+	 */
+	struct kobject		si_kobj;
+#ifdef CONFIG_DEBUG_FS
+	struct dentry		 *si_dbgaufs, *si_dbgaufs_xib;
+#ifdef CONFIG_AUFS_EXPORT
+	struct dentry		 *si_dbgaufs_xigen;
+#endif
+#endif
+
+	/* dirty, necessary for unmounting, sysfs and sysrq */
+	struct super_block	*si_sb;
+};
+
+/* sbinfo status flags */
+/*
+ * set true when refresh_dirs() failed at remount time.
+ * then try refreshing dirs at access time again.
+ * if it is false, refreshing dirs at access time is unnecesary
+ */
+#define AuSi_FAILED_REFRESH_DIRS	1
+#define AuSi_MAINTAIN_PLINK		(1 << 1)	/* ioctl */
+static inline unsigned char au_do_ftest_si(struct au_sbinfo *sbi,
+					   unsigned int flag)
+{
+	AuRwMustAnyLock(&sbi->si_rwsem);
+	return sbi->au_si_status & flag;
+}
+#define au_ftest_si(sbinfo, name)	au_do_ftest_si(sbinfo, AuSi_##name)
+#define au_fset_si(sbinfo, name) do { \
+	AuRwMustWriteLock(&(sbinfo)->si_rwsem); \
+	(sbinfo)->au_si_status |= AuSi_##name; \
+} while (0)
+#define au_fclr_si(sbinfo, name) do { \
+	AuRwMustWriteLock(&(sbinfo)->si_rwsem); \
+	(sbinfo)->au_si_status &= ~AuSi_##name; \
+} while (0)
+
+/* ---------------------------------------------------------------------- */
+
+/* policy to select one among writable branches */
+#define AuWbrCopyup(sbinfo, args...) \
+	((sbinfo)->si_wbr_copyup_ops->copyup(args))
+#define AuWbrCreate(sbinfo, args...) \
+	((sbinfo)->si_wbr_create_ops->create(args))
+
+/* flags for si_read_lock()/aufs_read_lock()/di_read_lock() */
+#define AuLock_DW		1		/* write-lock dentry */
+#define AuLock_IR		(1 << 1)	/* read-lock inode */
+#define AuLock_IW		(1 << 2)	/* write-lock inode */
+#define AuLock_FLUSH		(1 << 3)	/* wait for 'nowait' tasks */
+#define AuLock_DIR		(1 << 4)	/* target is a dir */
+#define au_ftest_lock(flags, name)	((flags) & AuLock_##name)
+#define au_fset_lock(flags, name)	{ (flags) |= AuLock_##name; }
+#define au_fclr_lock(flags, name)	{ (flags) &= ~AuLock_##name; }
+
+/* ---------------------------------------------------------------------- */
+
+/* super.c */
+extern struct file_system_type aufs_fs_type;
+struct inode *au_iget_locked(struct super_block *sb, ino_t ino);
+
+/* sbinfo.c */
+void au_si_free(struct kobject *kobj);
+int au_si_alloc(struct super_block *sb);
+int au_sbr_realloc(struct au_sbinfo *sbinfo, int nbr);
+
+unsigned int au_sigen_inc(struct super_block *sb);
+aufs_bindex_t au_new_br_id(struct super_block *sb);
+
+void aufs_read_lock(struct dentry *dentry, int flags);
+void aufs_read_unlock(struct dentry *dentry, int flags);
+void aufs_write_lock(struct dentry *dentry);
+void aufs_write_unlock(struct dentry *dentry);
+void aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int isdir);
+void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2);
+
+/* wbr_policy.c */
+extern struct au_wbr_copyup_operations au_wbr_copyup_ops[];
+extern struct au_wbr_create_operations au_wbr_create_ops[];
+int au_cpdown_dirs(struct dentry *dentry, aufs_bindex_t bdst);
+
+/* ---------------------------------------------------------------------- */
+
+static inline struct au_sbinfo *au_sbi(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_EXPORT
+void au_export_init(struct super_block *sb);
+
+static inline int au_test_nfsd(struct task_struct *tsk)
+{
+	return !tsk->mm && !strcmp(tsk->comm, "nfsd");
+}
+
+int au_xigen_inc(struct inode *inode);
+int au_xigen_new(struct inode *inode);
+int au_xigen_set(struct super_block *sb, struct file *base);
+void au_xigen_clr(struct super_block *sb);
+
+static inline int au_busy_or_stale(void)
+{
+	if (!au_test_nfsd(current))
+		return -EBUSY;
+	return -ESTALE;
+}
+#else
+static inline void au_export_init(struct super_block *sb)
+{
+	/* nothing */
+}
+
+static inline int au_test_nfsd(struct task_struct *tsk)
+{
+	return 0;
+}
+
+static inline int au_xigen_inc(struct inode *inode)
+{
+	return 0;
+}
+
+static inline int au_xigen_new(struct inode *inode)
+{
+	return 0;
+}
+
+static inline int au_xigen_set(struct super_block *sb, struct file *base)
+{
+	return 0;
+}
+
+static inline void au_xigen_clr(struct super_block *sb)
+{
+	/* empty */
+}
+
+static inline int au_busy_or_stale(void)
+{
+	return -EBUSY;
+}
+#endif /* CONFIG_AUFS_EXPORT */
+
+/* ---------------------------------------------------------------------- */
+
+static inline void dbgaufs_si_null(struct au_sbinfo *sbinfo)
+{
+	/*
+	 * This function is a dynamic '__init' fucntion actually,
+	 * so the tiny check for si_rwsem is unnecessary.
+	 */
+	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
+#ifdef CONFIG_DEBUG_FS
+	sbinfo->si_dbgaufs = NULL;
+	sbinfo->si_dbgaufs_xib = NULL;
+#ifdef CONFIG_AUFS_EXPORT
+	sbinfo->si_dbgaufs_xigen = NULL;
+#endif
+#endif
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* lock superblock. mainly for entry point functions */
+/*
+ * si_noflush_read_lock, si_noflush_write_lock,
+ * si_read_unlock, si_write_unlock, si_downgrade_lock
+ */
+AuSimpleLockRwsemFuncs(si_noflush, struct super_block *sb,
+		       &au_sbi(sb)->si_rwsem);
+AuSimpleUnlockRwsemFuncs(si, struct super_block *sb, &au_sbi(sb)->si_rwsem);
+
+#define SiMustNoWaiters(sb)	AuRwMustNoWaiters(&au_sbi(sb)->si_rwsem)
+#define SiMustAnyLock(sb)	AuRwMustAnyLock(&au_sbi(sb)->si_rwsem)
+#define SiMustWriteLock(sb)	AuRwMustWriteLock(&au_sbi(sb)->si_rwsem)
+
+static inline void si_read_lock(struct super_block *sb, int flags)
+{
+	if (au_ftest_lock(flags, FLUSH))
+		au_nwt_flush(&au_sbi(sb)->si_nowait);
+	si_noflush_read_lock(sb);
+}
+
+static inline void si_write_lock(struct super_block *sb)
+{
+	au_nwt_flush(&au_sbi(sb)->si_nowait);
+	si_noflush_write_lock(sb);
+}
+
+static inline int si_read_trylock(struct super_block *sb, int flags)
+{
+	if (au_ftest_lock(flags, FLUSH))
+		au_nwt_flush(&au_sbi(sb)->si_nowait);
+	return si_noflush_read_trylock(sb);
+}
+
+static inline int si_write_trylock(struct super_block *sb, int flags)
+{
+	if (au_ftest_lock(flags, FLUSH))
+		au_nwt_flush(&au_sbi(sb)->si_nowait);
+	return si_noflush_write_trylock(sb);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static inline aufs_bindex_t au_sbend(struct super_block *sb)
+{
+	SiMustAnyLock(sb);
+	return au_sbi(sb)->si_bend;
+}
+
+static inline unsigned int au_mntflags(struct super_block *sb)
+{
+	SiMustAnyLock(sb);
+	return au_sbi(sb)->si_mntflags;
+}
+
+static inline unsigned int au_sigen(struct super_block *sb)
+{
+	SiMustAnyLock(sb);
+	return au_sbi(sb)->si_generation;
+}
+
+static inline struct au_branch *au_sbr(struct super_block *sb,
+				       aufs_bindex_t bindex)
+{
+	SiMustAnyLock(sb);
+	return au_sbi(sb)->si_branch[0 + bindex];
+}
+
+static inline void au_xino_brid_set(struct super_block *sb, aufs_bindex_t brid)
+{
+	SiMustWriteLock(sb);
+	au_sbi(sb)->si_xino_brid = brid;
+}
+
+static inline aufs_bindex_t au_xino_brid(struct super_block *sb)
+{
+	SiMustAnyLock(sb);
+	return au_sbi(sb)->si_xino_brid;
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_SUPER_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/sysaufs.c linux-2.6.31.4/fs/aufs/sysaufs.c
--- linux-2.6.31.4.orig/fs/aufs/sysaufs.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/sysaufs.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sysfs interface and lifetime management
+ * they are necessary regardless sysfs is disabled.
+ */
+
+#include <linux/fs.h>
+#include <linux/random.h>
+#include <linux/sysfs.h>
+#include "aufs.h"
+
+unsigned long sysaufs_si_mask;
+struct kset *sysaufs_ket;
+
+#define AuSiAttr(_name) { \
+	.attr   = { .name = __stringify(_name), .mode = 0444 },	\
+	.show   = sysaufs_si_##_name,				\
+}
+
+static struct sysaufs_si_attr sysaufs_si_attr_xi_path = AuSiAttr(xi_path);
+struct attribute *sysaufs_si_attrs[] = {
+	&sysaufs_si_attr_xi_path.attr,
+	NULL,
+};
+
+static struct sysfs_ops au_sbi_ops = {
+	.show   = sysaufs_si_show
+};
+
+static struct kobj_type au_sbi_ktype = {
+	.release	= au_si_free,
+	.sysfs_ops	= &au_sbi_ops,
+	.default_attrs	= sysaufs_si_attrs
+};
+
+/* ---------------------------------------------------------------------- */
+
+int sysaufs_si_init(struct au_sbinfo *sbinfo)
+{
+	int err;
+
+	sbinfo->si_kobj.kset = sysaufs_ket;
+	/* cf. sysaufs_name() */
+	err = kobject_init_and_add
+		(&sbinfo->si_kobj, &au_sbi_ktype, /*&sysaufs_ket->kobj*/NULL,
+		 SysaufsSiNamePrefix "%lx", sysaufs_si_id(sbinfo));
+
+	dbgaufs_si_null(sbinfo);
+	if (!err) {
+		err = dbgaufs_si_init(sbinfo);
+		if (unlikely(err))
+			kobject_put(&sbinfo->si_kobj);
+	}
+	return err;
+}
+
+void sysaufs_fin(void)
+{
+	dbgaufs_fin();
+	sysfs_remove_group(&sysaufs_ket->kobj, sysaufs_attr_group);
+	kset_unregister(sysaufs_ket);
+}
+
+int __init sysaufs_init(void)
+{
+	int err;
+
+	do {
+		get_random_bytes(&sysaufs_si_mask, sizeof(sysaufs_si_mask));
+	} while (!sysaufs_si_mask);
+
+	sysaufs_ket = kset_create_and_add(AUFS_NAME, NULL, fs_kobj);
+	err = PTR_ERR(sysaufs_ket);
+	if (IS_ERR(sysaufs_ket))
+		goto out;
+	err = sysfs_create_group(&sysaufs_ket->kobj, sysaufs_attr_group);
+	if (unlikely(err)) {
+		kset_unregister(sysaufs_ket);
+		goto out;
+	}
+
+	err = dbgaufs_init();
+	if (unlikely(err))
+		sysaufs_fin();
+ out:
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/sysaufs.h linux-2.6.31.4/fs/aufs/sysaufs.h
--- linux-2.6.31.4.orig/fs/aufs/sysaufs.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/sysaufs.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sysfs interface and mount lifetime management
+ */
+
+#ifndef __SYSAUFS_H__
+#define __SYSAUFS_H__
+
+#ifdef __KERNEL__
+
+#include <linux/sysfs.h>
+#include <linux/aufs_type.h>
+#include "module.h"
+
+struct super_block;
+struct au_sbinfo;
+
+struct sysaufs_si_attr {
+	struct attribute attr;
+	int (*show)(struct seq_file *seq, struct super_block *sb);
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* sysaufs.c */
+extern unsigned long sysaufs_si_mask;
+extern struct kset *sysaufs_ket;
+extern struct attribute *sysaufs_si_attrs[];
+int sysaufs_si_init(struct au_sbinfo *sbinfo);
+int __init sysaufs_init(void);
+void sysaufs_fin(void);
+
+/* ---------------------------------------------------------------------- */
+
+/* some people doesn't like to show a pointer in kernel */
+static inline unsigned long sysaufs_si_id(struct au_sbinfo *sbinfo)
+{
+	return sysaufs_si_mask ^ (unsigned long)sbinfo;
+}
+
+#define SysaufsSiNamePrefix	"si_"
+#define SysaufsSiNameLen	(sizeof(SysaufsSiNamePrefix) + 16)
+static inline void sysaufs_name(struct au_sbinfo *sbinfo, char *name)
+{
+	snprintf(name, SysaufsSiNameLen, SysaufsSiNamePrefix "%lx",
+		 sysaufs_si_id(sbinfo));
+}
+
+struct au_branch;
+#ifdef CONFIG_SYSFS
+/* sysfs.c */
+extern struct attribute_group *sysaufs_attr_group;
+
+int sysaufs_si_xi_path(struct seq_file *seq, struct super_block *sb);
+ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
+			 char *buf);
+
+void sysaufs_br_init(struct au_branch *br);
+void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex);
+void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex);
+
+#define sysaufs_brs_init()	do {} while (0)
+
+#else
+#define sysaufs_attr_group	NULL
+
+static inline
+int sysaufs_si_xi_path(struct seq_file *seq, struct super_block *sb)
+{
+	return 0;
+}
+
+static inline
+ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
+			 char *buf)
+{
+	return 0;
+}
+
+static inline void sysaufs_br_init(struct au_branch *br)
+{
+	/* empty */
+}
+
+static inline void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
+{
+	/* nothing */
+}
+
+static inline void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
+{
+	/* nothing */
+}
+
+static inline void sysaufs_brs_init(void)
+{
+	sysaufs_brs = 0;
+}
+
+#endif /* CONFIG_SYSFS */
+
+#endif /* __KERNEL__ */
+#endif /* __SYSAUFS_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/sysfs.c linux-2.6.31.4/fs/aufs/sysfs.c
--- linux-2.6.31.4.orig/fs/aufs/sysfs.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/sysfs.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,210 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sysfs interface
+ */
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/sysfs.h>
+#include "aufs.h"
+
+static struct attribute *au_attr[] = {
+	NULL,	/* need to NULL terminate the list of attributes */
+};
+
+static struct attribute_group sysaufs_attr_group_body = {
+	.attrs = au_attr
+};
+
+struct attribute_group *sysaufs_attr_group = &sysaufs_attr_group_body;
+
+/* ---------------------------------------------------------------------- */
+
+int sysaufs_si_xi_path(struct seq_file *seq, struct super_block *sb)
+{
+	int err;
+
+	SiMustAnyLock(sb);
+
+	err = 0;
+	if (au_opt_test(au_mntflags(sb), XINO)) {
+		err = au_xino_path(seq, au_sbi(sb)->si_xib);
+		seq_putc(seq, '\n');
+	}
+	return err;
+}
+
+/*
+ * the lifetime of branch is independent from the entry under sysfs.
+ * sysfs handles the lifetime of the entry, and never call ->show() after it is
+ * unlinked.
+ */
+static int sysaufs_si_br(struct seq_file *seq, struct super_block *sb,
+			 aufs_bindex_t bindex)
+{
+	struct path path;
+	struct dentry *root;
+	struct au_branch *br;
+
+	AuDbg("b%d\n", bindex);
+
+	root = sb->s_root;
+	di_read_lock_parent(root, !AuLock_IR);
+	br = au_sbr(sb, bindex);
+	path.mnt = br->br_mnt;
+	path.dentry = au_h_dptr(root, bindex);
+	au_seq_path(seq, &path);
+	di_read_unlock(root, !AuLock_IR);
+	seq_printf(seq, "=%s\n", au_optstr_br_perm(br->br_perm));
+	return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct seq_file *au_seq(char *p, ssize_t len)
+{
+	struct seq_file *seq;
+
+	seq = kzalloc(sizeof(*seq), GFP_NOFS);
+	if (seq) {
+		/* mutex_init(&seq.lock); */
+		seq->buf = p;
+		seq->size = len;
+		return seq; /* success */
+	}
+
+	seq = ERR_PTR(-ENOMEM);
+	return seq;
+}
+
+#define SysaufsBr_PREFIX "br"
+
+/* todo: file size may exceed PAGE_SIZE */
+ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
+			 char *buf)
+{
+	ssize_t err;
+	long l;
+	aufs_bindex_t bend;
+	struct au_sbinfo *sbinfo;
+	struct super_block *sb;
+	struct seq_file *seq;
+	char *name;
+	struct attribute **cattr;
+
+	sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
+	sb = sbinfo->si_sb;
+	si_noflush_read_lock(sb);
+
+	seq = au_seq(buf, PAGE_SIZE);
+	err = PTR_ERR(seq);
+	if (IS_ERR(seq))
+		goto out;
+
+	name = (void *)attr->name;
+	cattr = sysaufs_si_attrs;
+	while (*cattr) {
+		if (!strcmp(name, (*cattr)->name)) {
+			err = container_of(*cattr, struct sysaufs_si_attr, attr)
+				->show(seq, sb);
+			goto out_seq;
+		}
+		cattr++;
+	}
+
+	bend = au_sbend(sb);
+	if (!strncmp(name, SysaufsBr_PREFIX, sizeof(SysaufsBr_PREFIX) - 1)) {
+		name += sizeof(SysaufsBr_PREFIX) - 1;
+		err = strict_strtol(name, 10, &l);
+		if (!err) {
+			if (l <= bend)
+				err = sysaufs_si_br(seq, sb, (aufs_bindex_t)l);
+			else
+				err = -ENOENT;
+		}
+		goto out_seq;
+	}
+	BUG();
+
+ out_seq:
+	if (!err) {
+		err = seq->count;
+		/* sysfs limit */
+		if (unlikely(err == PAGE_SIZE))
+			err = -EFBIG;
+	}
+	kfree(seq);
+ out:
+	si_read_unlock(sb);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void sysaufs_br_init(struct au_branch *br)
+{
+	br->br_attr.name = br->br_name;
+	br->br_attr.mode = S_IRUGO;
+	br->br_attr.owner = THIS_MODULE;
+}
+
+void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
+{
+	struct au_branch *br;
+	struct kobject *kobj;
+	aufs_bindex_t bend;
+
+	dbgaufs_brs_del(sb, bindex);
+
+	if (!sysaufs_brs)
+		return;
+
+	kobj = &au_sbi(sb)->si_kobj;
+	bend = au_sbend(sb);
+	for (; bindex <= bend; bindex++) {
+		br = au_sbr(sb, bindex);
+		sysfs_remove_file(kobj, &br->br_attr);
+	}
+}
+
+void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
+{
+	int err;
+	aufs_bindex_t bend;
+	struct kobject *kobj;
+	struct au_branch *br;
+
+	dbgaufs_brs_add(sb, bindex);
+
+	if (!sysaufs_brs)
+		return;
+
+	kobj = &au_sbi(sb)->si_kobj;
+	bend = au_sbend(sb);
+	for (; bindex <= bend; bindex++) {
+		br = au_sbr(sb, bindex);
+		snprintf(br->br_name, sizeof(br->br_name), SysaufsBr_PREFIX
+			 "%d", bindex);
+		err = sysfs_create_file(kobj, &br->br_attr);
+		if (unlikely(err))
+			AuWarn("failed %s under sysfs(%d)\n", br->br_name, err);
+	}
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/sysrq.c linux-2.6.31.4/fs/aufs/sysrq.c
--- linux-2.6.31.4.orig/fs/aufs/sysrq.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/sysrq.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * magic sysrq hanlder
+ */
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+/* #include <linux/sysrq.h> */
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+static void sysrq_sb(struct super_block *sb)
+{
+	char *plevel;
+	struct au_sbinfo *sbinfo;
+	struct file *file;
+
+	plevel = au_plevel;
+	au_plevel = KERN_WARNING;
+	au_debug(1);
+
+	sbinfo = au_sbi(sb);
+	pr_warning("si=%lx\n", sysaufs_si_id(sbinfo));
+	pr_warning(AUFS_NAME ": superblock\n");
+	au_dpri_sb(sb);
+	pr_warning(AUFS_NAME ": root dentry\n");
+	au_dpri_dentry(sb->s_root);
+	pr_warning(AUFS_NAME ": root inode\n");
+	au_dpri_inode(sb->s_root->d_inode);
+#if 0
+	struct inode *i;
+	pr_warning(AUFS_NAME ": isolated inode\n");
+	list_for_each_entry(i, &sb->s_inodes, i_sb_list)
+		if (list_empty(&i->i_dentry))
+			au_dpri_inode(i);
+#endif
+	pr_warning(AUFS_NAME ": files\n");
+	list_for_each_entry(file, &sb->s_files, f_u.fu_list)
+		if (!special_file(file->f_dentry->d_inode->i_mode))
+			au_dpri_file(file);
+
+	au_plevel = plevel;
+	au_debug(0);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* module parameter */
+static char *aufs_sysrq_key = "a";
+module_param_named(sysrq, aufs_sysrq_key, charp, S_IRUGO);
+MODULE_PARM_DESC(sysrq, "MagicSysRq key for " AUFS_NAME);
+
+static void au_sysrq(int key __maybe_unused,
+		     struct tty_struct *tty __maybe_unused)
+{
+	struct kobject *kobj;
+	struct au_sbinfo *sbinfo;
+
+	/* spin_lock(&sysaufs_ket->list_lock); */
+	list_for_each_entry(kobj, &sysaufs_ket->list, entry) {
+		sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
+		sysrq_sb(sbinfo->si_sb);
+	}
+	/* spin_unlock(&sysaufs_ket->list_lock); */
+}
+
+static struct sysrq_key_op au_sysrq_op = {
+	.handler	= au_sysrq,
+	.help_msg	= "Aufs",
+	.action_msg	= "Aufs",
+	.enable_mask	= SYSRQ_ENABLE_DUMP
+};
+
+/* ---------------------------------------------------------------------- */
+
+int __init au_sysrq_init(void)
+{
+	int err;
+	char key;
+
+	err = -1;
+	key = *aufs_sysrq_key;
+	if ('a' <= key && key <= 'z')
+		err = register_sysrq_key(key, &au_sysrq_op);
+	if (unlikely(err))
+		AuErr("err %d, sysrq=%c\n", err, key);
+	return err;
+}
+
+void au_sysrq_fin(void)
+{
+	int err;
+	err = unregister_sysrq_key(*aufs_sysrq_key, &au_sysrq_op);
+	if (unlikely(err))
+		AuErr("err %d (ignored)\n", err);
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/vdir.c linux-2.6.31.4/fs/aufs/vdir.c
--- linux-2.6.31.4.orig/fs/aufs/vdir.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/vdir.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,882 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * virtual or vertical directory
+ */
+
+#include <linux/hash.h>
+#include "aufs.h"
+
+static unsigned int calc_size(int nlen)
+{
+	BUILD_BUG_ON(sizeof(ino_t) != sizeof(long));
+	return ALIGN(sizeof(struct au_vdir_de) + nlen, sizeof(ino_t));
+}
+
+static int set_deblk_end(union au_vdir_deblk_p *p,
+			 union au_vdir_deblk_p *deblk_end)
+{
+	if (calc_size(0) <= deblk_end->deblk - p->deblk) {
+		p->de->de_str.len = 0;
+		/* smp_mb(); */
+		return 0;
+	}
+	return -1; /* error */
+}
+
+/* returns true or false */
+static int is_deblk_end(union au_vdir_deblk_p *p,
+			union au_vdir_deblk_p *deblk_end)
+{
+	if (calc_size(0) <= deblk_end->deblk - p->deblk)
+		return !p->de->de_str.len;
+	return 1;
+}
+
+static unsigned char *last_deblk(struct au_vdir *vdir)
+{
+	return vdir->vd_deblk[vdir->vd_nblk - 1];
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * the allocated memory has to be freed by
+ * au_nhash_wh_free() or au_nhash_de_free().
+ */
+int au_nhash_alloc(struct au_nhash *nhash, unsigned int num_hash, gfp_t gfp)
+{
+	struct hlist_head *head;
+	unsigned int u;
+
+	head = kmalloc(sizeof(*nhash->nh_head) * num_hash, gfp);
+	if (head) {
+		nhash->nh_num = num_hash;
+		nhash->nh_head = head;
+		for (u = 0; u < num_hash; u++)
+			INIT_HLIST_HEAD(head++);
+		return 0; /* success */
+	}
+
+	return -ENOMEM;
+}
+
+static void nhash_count(struct hlist_head *head)
+{
+#if 0
+	unsigned long n;
+	struct hlist_node *pos;
+
+	n = 0;
+	hlist_for_each(pos, head)
+		n++;
+	AuInfo("%lu\n", n);
+#endif
+}
+
+static void au_nhash_wh_do_free(struct hlist_head *head)
+{
+	struct au_vdir_wh *tpos;
+	struct hlist_node *pos, *node;
+
+	hlist_for_each_entry_safe(tpos, pos, node, head, wh_hash) {
+		/* hlist_del(pos); */
+		kfree(tpos);
+	}
+}
+
+static void au_nhash_de_do_free(struct hlist_head *head)
+{
+	struct au_vdir_dehstr *tpos;
+	struct hlist_node *pos, *node;
+
+	hlist_for_each_entry_safe(tpos, pos, node, head, hash) {
+		/* hlist_del(pos); */
+		au_cache_free_dehstr(tpos);
+	}
+}
+
+static void au_nhash_do_free(struct au_nhash *nhash,
+			     void (*free)(struct hlist_head *head))
+{
+	unsigned int u, n;
+	struct hlist_head *head;
+
+	n = nhash->nh_num;
+	head = nhash->nh_head;
+	for (u = 0; u < n; u++) {
+		nhash_count(head);
+		free(head++);
+	}
+	kfree(nhash->nh_head);
+}
+
+void au_nhash_wh_free(struct au_nhash *whlist)
+{
+	au_nhash_do_free(whlist, au_nhash_wh_do_free);
+}
+
+static void au_nhash_de_free(struct au_nhash *delist)
+{
+	au_nhash_do_free(delist, au_nhash_de_do_free);
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_nhash_test_longer_wh(struct au_nhash *whlist, aufs_bindex_t btgt,
+			    int limit)
+{
+	int num;
+	unsigned int u, n;
+	struct hlist_head *head;
+	struct au_vdir_wh *tpos;
+	struct hlist_node *pos;
+
+	num = 0;
+	n = whlist->nh_num;
+	head = whlist->nh_head;
+	for (u = 0; u < n; u++) {
+		hlist_for_each_entry(tpos, pos, head, wh_hash)
+			if (tpos->wh_bindex == btgt && ++num > limit)
+				return 1;
+		head++;
+	}
+	return 0;
+}
+
+static struct hlist_head *au_name_hash(struct au_nhash *nhash,
+				       unsigned char *name,
+				       unsigned int len)
+{
+	unsigned int v;
+	/* const unsigned int magic_bit = 12; */
+
+	v = 0;
+	while (len--)
+		v += *name++;
+	/* v = hash_long(v, magic_bit); */
+	v %= nhash->nh_num;
+	return nhash->nh_head + v;
+}
+
+static int au_nhash_test_name(struct au_vdir_destr *str, const char *name,
+			      int nlen)
+{
+	return str->len == nlen && !memcmp(str->name, name, nlen);
+}
+
+/* returns found or not */
+int au_nhash_test_known_wh(struct au_nhash *whlist, char *name, int nlen)
+{
+	struct hlist_head *head;
+	struct au_vdir_wh *tpos;
+	struct hlist_node *pos;
+	struct au_vdir_destr *str;
+
+	head = au_name_hash(whlist, name, nlen);
+	hlist_for_each_entry(tpos, pos, head, wh_hash) {
+		str = &tpos->wh_str;
+		AuDbg("%.*s\n", str->len, str->name);
+		if (au_nhash_test_name(str, name, nlen))
+			return 1;
+	}
+	return 0;
+}
+
+/* returns found(true) or not */
+static int test_known(struct au_nhash *delist, char *name, int nlen)
+{
+	struct hlist_head *head;
+	struct au_vdir_dehstr *tpos;
+	struct hlist_node *pos;
+	struct au_vdir_destr *str;
+
+	head = au_name_hash(delist, name, nlen);
+	hlist_for_each_entry(tpos, pos, head, hash) {
+		str = tpos->str;
+		AuDbg("%.*s\n", str->len, str->name);
+		if (au_nhash_test_name(str, name, nlen))
+			return 1;
+	}
+	return 0;
+}
+
+static void au_shwh_init_wh(struct au_vdir_wh *wh, ino_t ino,
+			    unsigned char d_type)
+{
+#ifdef CONFIG_AUFS_SHWH
+	wh->wh_ino = ino;
+	wh->wh_type = d_type;
+#endif
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_nhash_append_wh(struct au_nhash *whlist, char *name, int nlen, ino_t ino,
+		       unsigned int d_type, aufs_bindex_t bindex,
+		       unsigned char shwh)
+{
+	int err;
+	struct au_vdir_destr *str;
+	struct au_vdir_wh *wh;
+
+	AuDbg("%.*s\n", nlen, name);
+	err = -ENOMEM;
+	wh = kmalloc(sizeof(*wh) + nlen, GFP_NOFS);
+	if (unlikely(!wh))
+		goto out;
+
+	err = 0;
+	wh->wh_bindex = bindex;
+	if (shwh)
+		au_shwh_init_wh(wh, ino, d_type);
+	str = &wh->wh_str;
+	str->len = nlen;
+	memcpy(str->name, name, nlen);
+	hlist_add_head(&wh->wh_hash, au_name_hash(whlist, name, nlen));
+	/* smp_mb(); */
+
+ out:
+	return err;
+}
+
+static int append_deblk(struct au_vdir *vdir)
+{
+	int err;
+	unsigned long ul;
+	const unsigned int deblk_sz = vdir->vd_deblk_sz;
+	union au_vdir_deblk_p p, deblk_end;
+	unsigned char **o;
+
+	err = -ENOMEM;
+	o = krealloc(vdir->vd_deblk, sizeof(*o) * (vdir->vd_nblk + 1),
+		     GFP_NOFS);
+	if (unlikely(!o))
+		goto out;
+
+	vdir->vd_deblk = o;
+	p.deblk = kmalloc(deblk_sz, GFP_NOFS);
+	if (p.deblk) {
+		ul = vdir->vd_nblk++;
+		vdir->vd_deblk[ul] = p.deblk;
+		vdir->vd_last.ul = ul;
+		vdir->vd_last.p.deblk = p.deblk;
+		deblk_end.deblk = p.deblk + deblk_sz;
+		err = set_deblk_end(&p, &deblk_end);
+	}
+
+ out:
+	return err;
+}
+
+static int append_de(struct au_vdir *vdir, char *name, int nlen, ino_t ino,
+		     unsigned int d_type, struct au_nhash *delist)
+{
+	int err;
+	unsigned int sz;
+	const unsigned int deblk_sz = vdir->vd_deblk_sz;
+	union au_vdir_deblk_p p, *room, deblk_end;
+	struct au_vdir_dehstr *dehstr;
+
+	p.deblk = last_deblk(vdir);
+	deblk_end.deblk = p.deblk + deblk_sz;
+	room = &vdir->vd_last.p;
+	AuDebugOn(room->deblk < p.deblk || deblk_end.deblk <= room->deblk
+		  || !is_deblk_end(room, &deblk_end));
+
+	sz = calc_size(nlen);
+	if (unlikely(sz > deblk_end.deblk - room->deblk)) {
+		err = append_deblk(vdir);
+		if (unlikely(err))
+			goto out;
+
+		p.deblk = last_deblk(vdir);
+		deblk_end.deblk = p.deblk + deblk_sz;
+		/* smp_mb(); */
+		AuDebugOn(room->deblk != p.deblk);
+	}
+
+	err = -ENOMEM;
+	dehstr = au_cache_alloc_dehstr();
+	if (unlikely(!dehstr))
+		goto out;
+
+	dehstr->str = &room->de->de_str;
+	hlist_add_head(&dehstr->hash, au_name_hash(delist, name, nlen));
+	room->de->de_ino = ino;
+	room->de->de_type = d_type;
+	room->de->de_str.len = nlen;
+	memcpy(room->de->de_str.name, name, nlen);
+
+	err = 0;
+	room->deblk += sz;
+	if (unlikely(set_deblk_end(room, &deblk_end)))
+		err = append_deblk(vdir);
+	/* smp_mb(); */
+
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_vdir_free(struct au_vdir *vdir)
+{
+	unsigned char **deblk;
+
+	deblk = vdir->vd_deblk;
+	while (vdir->vd_nblk--)
+		kfree(*deblk++);
+	kfree(vdir->vd_deblk);
+	au_cache_free_vdir(vdir);
+}
+
+static struct au_vdir *alloc_vdir(struct super_block *sb)
+{
+	struct au_vdir *vdir;
+	int err;
+
+	SiMustAnyLock(sb);
+
+	err = -ENOMEM;
+	vdir = au_cache_alloc_vdir();
+	if (unlikely(!vdir))
+		goto out;
+
+	vdir->vd_deblk = kzalloc(sizeof(*vdir->vd_deblk), GFP_NOFS);
+	if (unlikely(!vdir->vd_deblk))
+		goto out_free;
+
+	vdir->vd_deblk_sz = au_sbi(sb)->si_rdblk;
+	vdir->vd_nblk = 0;
+	vdir->vd_version = 0;
+	vdir->vd_jiffy = 0;
+	err = append_deblk(vdir);
+	if (!err)
+		return vdir; /* success */
+
+	kfree(vdir->vd_deblk);
+
+ out_free:
+	au_cache_free_vdir(vdir);
+ out:
+	vdir = ERR_PTR(err);
+	return vdir;
+}
+
+static int reinit_vdir(struct au_vdir *vdir)
+{
+	int err;
+	union au_vdir_deblk_p p, deblk_end;
+
+	while (vdir->vd_nblk > 1) {
+		kfree(vdir->vd_deblk[vdir->vd_nblk - 1]);
+		/* vdir->vd_deblk[vdir->vd_nblk - 1] = NULL; */
+		vdir->vd_nblk--;
+	}
+	p.deblk = vdir->vd_deblk[0];
+	deblk_end.deblk = p.deblk + vdir->vd_deblk_sz;
+	err = set_deblk_end(&p, &deblk_end);
+	/* keep vd_dblk_sz */
+	vdir->vd_last.ul = 0;
+	vdir->vd_last.p.deblk = vdir->vd_deblk[0];
+	vdir->vd_version = 0;
+	vdir->vd_jiffy = 0;
+	/* smp_mb(); */
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_ino(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		  unsigned int d_type, ino_t *ino)
+{
+	int err;
+	struct mutex *mtx;
+	const int isdir = (d_type == DT_DIR);
+
+	/* prevent hardlinks from race condition */
+	mtx = NULL;
+	if (!isdir) {
+		mtx = &au_sbr(sb, bindex)->br_xino.xi_nondir_mtx;
+		mutex_lock(mtx);
+	}
+	err = au_xino_read(sb, bindex, h_ino, ino);
+	if (unlikely(err))
+		goto out;
+
+	if (!*ino) {
+		err = -EIO;
+		*ino = au_xino_new_ino(sb);
+		if (unlikely(!*ino))
+			goto out;
+		err = au_xino_write(sb, bindex, h_ino, *ino);
+		if (unlikely(err))
+			goto out;
+	}
+
+ out:
+	if (!isdir)
+		mutex_unlock(mtx);
+	return err;
+}
+
+static int au_wh_ino(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		     unsigned int d_type, ino_t *ino)
+{
+#ifdef CONFIG_AUFS_SHWH
+	return au_ino(sb, bindex, h_ino, d_type, ino);
+#else
+	return 0;
+#endif
+}
+
+#define AuFillVdir_CALLED	1
+#define AuFillVdir_WHABLE	(1 << 1)
+#define AuFillVdir_SHWH		(1 << 2)
+#define au_ftest_fillvdir(flags, name)	((flags) & AuFillVdir_##name)
+#define au_fset_fillvdir(flags, name)	{ (flags) |= AuFillVdir_##name; }
+#define au_fclr_fillvdir(flags, name)	{ (flags) &= ~AuFillVdir_##name; }
+
+#ifndef CONFIG_AUFS_SHWH
+#undef AuFillVdir_SHWH
+#define AuFillVdir_SHWH		0
+#endif
+
+struct fillvdir_arg {
+	struct file		*file;
+	struct au_vdir		*vdir;
+	struct au_nhash		delist;
+	struct au_nhash		whlist;
+	aufs_bindex_t		bindex;
+	unsigned int		flags;
+	int			err;
+};
+
+static int fillvdir(void *__arg, const char *__name, int nlen,
+		    loff_t offset __maybe_unused, u64 h_ino,
+		    unsigned int d_type)
+{
+	struct fillvdir_arg *arg = __arg;
+	char *name = (void *)__name;
+	struct super_block *sb;
+	ino_t ino;
+	const unsigned char shwh = !!au_ftest_fillvdir(arg->flags, SHWH);
+
+	arg->err = 0;
+	sb = arg->file->f_dentry->d_sb;
+	au_fset_fillvdir(arg->flags, CALLED);
+	/* smp_mb(); */
+	if (nlen <= AUFS_WH_PFX_LEN
+	    || memcmp(name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
+		if (test_known(&arg->delist, name, nlen)
+		    || au_nhash_test_known_wh(&arg->whlist, name, nlen))
+			goto out; /* already exists or whiteouted */
+
+		sb = arg->file->f_dentry->d_sb;
+		arg->err = au_ino(sb, arg->bindex, h_ino, d_type, &ino);
+		if (!arg->err)
+			arg->err = append_de(arg->vdir, name, nlen, ino,
+					     d_type, &arg->delist);
+	} else if (au_ftest_fillvdir(arg->flags, WHABLE)) {
+		name += AUFS_WH_PFX_LEN;
+		nlen -= AUFS_WH_PFX_LEN;
+		if (au_nhash_test_known_wh(&arg->whlist, name, nlen))
+			goto out; /* already whiteouted */
+
+		if (shwh)
+			arg->err = au_wh_ino(sb, arg->bindex, h_ino, d_type,
+					     &ino);
+		if (!arg->err)
+			arg->err = au_nhash_append_wh
+				(&arg->whlist, name, nlen, ino, d_type,
+				 arg->bindex, shwh);
+	}
+
+ out:
+	if (!arg->err)
+		arg->vdir->vd_jiffy = jiffies;
+	/* smp_mb(); */
+	AuTraceErr(arg->err);
+	return arg->err;
+}
+
+static int au_handle_shwh(struct super_block *sb, struct au_vdir *vdir,
+			  struct au_nhash *whlist, struct au_nhash *delist)
+{
+#ifdef CONFIG_AUFS_SHWH
+	int err;
+	unsigned int nh, u;
+	struct hlist_head *head;
+	struct au_vdir_wh *tpos;
+	struct hlist_node *pos, *n;
+	char *p, *o;
+	struct au_vdir_destr *destr;
+
+	AuDebugOn(!au_opt_test(au_mntflags(sb), SHWH));
+
+	err = -ENOMEM;
+	o = p = __getname();
+	if (unlikely(!p))
+		goto out;
+
+	err = 0;
+	nh = whlist->nh_num;
+	memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
+	p += AUFS_WH_PFX_LEN;
+	for (u = 0; u < nh; u++) {
+		head = whlist->nh_head + u;
+		hlist_for_each_entry_safe(tpos, pos, n, head, wh_hash) {
+			destr = &tpos->wh_str;
+			memcpy(p, destr->name, destr->len);
+			err = append_de(vdir, o, destr->len + AUFS_WH_PFX_LEN,
+					tpos->wh_ino, tpos->wh_type, delist);
+			if (unlikely(err))
+				break;
+		}
+	}
+
+	__putname(o);
+
+ out:
+	AuTraceErr(err);
+	return err;
+#else
+	return 0;
+#endif
+}
+
+static int au_do_read_vdir(struct fillvdir_arg *arg)
+{
+	int err;
+	unsigned int rdhash;
+	loff_t offset;
+	aufs_bindex_t bend, bindex, bstart;
+	unsigned char shwh;
+	struct file *hf, *file;
+	struct super_block *sb;
+
+	file = arg->file;
+	sb = file->f_dentry->d_sb;
+	SiMustAnyLock(sb);
+
+	rdhash = au_sbi(sb)->si_rdhash;
+	err = au_nhash_alloc(&arg->delist, rdhash, GFP_NOFS);
+	if (unlikely(err))
+		goto out;
+	err = au_nhash_alloc(&arg->whlist, rdhash, GFP_NOFS);
+	if (unlikely(err))
+		goto out_delist;
+
+	err = 0;
+	arg->flags = 0;
+	shwh = 0;
+	if (au_opt_test(au_mntflags(sb), SHWH)) {
+		shwh = 1;
+		au_fset_fillvdir(arg->flags, SHWH);
+	}
+	bstart = au_fbstart(file);
+	bend = au_fbend(file);
+	for (bindex = bstart; !err && bindex <= bend; bindex++) {
+		hf = au_h_fptr(file, bindex);
+		if (!hf)
+			continue;
+
+		offset = vfsub_llseek(hf, 0, SEEK_SET);
+		err = offset;
+		if (unlikely(offset))
+			break;
+
+		arg->bindex = bindex;
+		au_fclr_fillvdir(arg->flags, WHABLE);
+		if (shwh
+		    || (bindex != bend
+			&& au_br_whable(au_sbr_perm(sb, bindex))))
+			au_fset_fillvdir(arg->flags, WHABLE);
+		do {
+			arg->err = 0;
+			au_fclr_fillvdir(arg->flags, CALLED);
+			/* smp_mb(); */
+			err = vfsub_readdir(hf, fillvdir, arg);
+			if (err >= 0)
+				err = arg->err;
+		} while (!err && au_ftest_fillvdir(arg->flags, CALLED));
+	}
+
+	if (!err && shwh)
+		err = au_handle_shwh(sb, arg->vdir, &arg->whlist, &arg->delist);
+
+	au_nhash_wh_free(&arg->whlist);
+
+ out_delist:
+	au_nhash_de_free(&arg->delist);
+ out:
+	return err;
+}
+
+static int read_vdir(struct file *file, int may_read)
+{
+	int err;
+	unsigned long expire;
+	unsigned char do_read;
+	struct fillvdir_arg arg;
+	struct inode *inode;
+	struct au_vdir *vdir, *allocated;
+
+	err = 0;
+	inode = file->f_dentry->d_inode;
+	IMustLock(inode);
+	SiMustAnyLock(inode->i_sb);
+
+	allocated = NULL;
+	do_read = 0;
+	expire = au_sbi(inode->i_sb)->si_rdcache;
+	vdir = au_ivdir(inode);
+	if (!vdir) {
+		do_read = 1;
+		vdir = alloc_vdir(inode->i_sb);
+		err = PTR_ERR(vdir);
+		if (IS_ERR(vdir))
+			goto out;
+		err = 0;
+		allocated = vdir;
+	} else if (may_read
+		   && (inode->i_version != vdir->vd_version
+		       || time_after(jiffies, vdir->vd_jiffy + expire))) {
+		do_read = 1;
+		err = reinit_vdir(vdir);
+		if (unlikely(err))
+			goto out;
+	}
+
+	if (!do_read)
+		return 0; /* success */
+
+	arg.file = file;
+	arg.vdir = vdir;
+	err = au_do_read_vdir(&arg);
+	if (!err) {
+		/* file->f_pos = 0; */
+		vdir->vd_version = inode->i_version;
+		vdir->vd_last.ul = 0;
+		vdir->vd_last.p.deblk = vdir->vd_deblk[0];
+		if (allocated)
+			au_set_ivdir(inode, allocated);
+	} else if (allocated)
+		au_vdir_free(allocated);
+
+ out:
+	return err;
+}
+
+static int copy_vdir(struct au_vdir *tgt, struct au_vdir *src)
+{
+	int err, rerr;
+	unsigned long ul, n;
+	const unsigned int deblk_sz = src->vd_deblk_sz;
+
+	AuDebugOn(tgt->vd_nblk != 1);
+
+	err = -ENOMEM;
+	if (tgt->vd_nblk < src->vd_nblk) {
+		unsigned char **p;
+
+		p = krealloc(tgt->vd_deblk, sizeof(*p) * src->vd_nblk,
+			     GFP_NOFS);
+		if (unlikely(!p))
+			goto out;
+		tgt->vd_deblk = p;
+	}
+
+	tgt->vd_nblk = src->vd_nblk;
+	tgt->vd_deblk_sz = deblk_sz;
+	memcpy(tgt->vd_deblk[0], src->vd_deblk[0], deblk_sz);
+	/* tgt->vd_last.i = 0; */
+	/* tgt->vd_last.p.deblk = tgt->vd_deblk[0]; */
+	tgt->vd_version = src->vd_version;
+	tgt->vd_jiffy = src->vd_jiffy;
+
+	n = src->vd_nblk;
+	for (ul = 1; ul < n; ul++) {
+		tgt->vd_deblk[ul] = kmemdup(src->vd_deblk[ul], deblk_sz,
+					    GFP_NOFS);
+		if (unlikely(!tgt->vd_deblk[ul]))
+			goto out;
+	}
+	/* smp_mb(); */
+	return 0; /* success */
+
+ out:
+	rerr = reinit_vdir(tgt);
+	BUG_ON(rerr);
+	return err;
+}
+
+int au_vdir_init(struct file *file)
+{
+	int err;
+	struct inode *inode;
+	struct au_vdir *vdir_cache, *allocated;
+
+	err = read_vdir(file, !file->f_pos);
+	if (unlikely(err))
+		goto out;
+
+	allocated = NULL;
+	vdir_cache = au_fvdir_cache(file);
+	if (!vdir_cache) {
+		vdir_cache = alloc_vdir(file->f_dentry->d_sb);
+		err = PTR_ERR(vdir_cache);
+		if (IS_ERR(vdir_cache))
+			goto out;
+		allocated = vdir_cache;
+	} else if (!file->f_pos && vdir_cache->vd_version != file->f_version) {
+		err = reinit_vdir(vdir_cache);
+		if (unlikely(err))
+			goto out;
+	} else
+		return 0; /* success */
+
+	inode = file->f_dentry->d_inode;
+	err = copy_vdir(vdir_cache, au_ivdir(inode));
+	if (!err) {
+		file->f_version = inode->i_version;
+		if (allocated)
+			au_set_fvdir_cache(file, allocated);
+	} else if (allocated)
+		au_vdir_free(allocated);
+
+ out:
+	return err;
+}
+
+static loff_t calc_offset(struct au_vdir *vdir)
+{
+	loff_t offset;
+	union au_vdir_deblk_p p;
+
+	p.deblk = vdir->vd_deblk[vdir->vd_last.ul];
+	offset = vdir->vd_last.p.deblk - p.deblk;
+	offset += vdir->vd_deblk_sz * vdir->vd_last.ul;
+	return offset;
+}
+
+/* returns true or false */
+static int seek_vdir(struct file *file)
+{
+	int valid;
+	unsigned int deblk_sz;
+	unsigned long ul, n;
+	loff_t offset;
+	union au_vdir_deblk_p p, deblk_end;
+	struct au_vdir *vdir_cache;
+
+	valid = 1;
+	vdir_cache = au_fvdir_cache(file);
+	offset = calc_offset(vdir_cache);
+	AuDbg("offset %lld\n", offset);
+	if (file->f_pos == offset)
+		goto out;
+
+	vdir_cache->vd_last.ul = 0;
+	vdir_cache->vd_last.p.deblk = vdir_cache->vd_deblk[0];
+	if (!file->f_pos)
+		goto out;
+
+	valid = 0;
+	deblk_sz = vdir_cache->vd_deblk_sz;
+	ul = div64_u64(file->f_pos, deblk_sz);
+	AuDbg("ul %lu\n", ul);
+	if (ul >= vdir_cache->vd_nblk)
+		goto out;
+
+	n = vdir_cache->vd_nblk;
+	for (; ul < n; ul++) {
+		p.deblk = vdir_cache->vd_deblk[ul];
+		deblk_end.deblk = p.deblk + deblk_sz;
+		offset = ul;
+		offset *= deblk_sz;
+		while (!is_deblk_end(&p, &deblk_end) && offset < file->f_pos) {
+			unsigned int l;
+
+			l = calc_size(p.de->de_str.len);
+			offset += l;
+			p.deblk += l;
+		}
+		if (!is_deblk_end(&p, &deblk_end)) {
+			valid = 1;
+			vdir_cache->vd_last.ul = ul;
+			vdir_cache->vd_last.p = p;
+			break;
+		}
+	}
+
+ out:
+	/* smp_mb(); */
+	AuTraceErr(!valid);
+	return valid;
+}
+
+int au_vdir_fill_de(struct file *file, void *dirent, filldir_t filldir)
+{
+	int err;
+	unsigned int l, deblk_sz;
+	union au_vdir_deblk_p deblk_end;
+	struct au_vdir *vdir_cache;
+	struct au_vdir_de *de;
+
+	vdir_cache = au_fvdir_cache(file);
+	if (!seek_vdir(file))
+		return 0;
+
+	deblk_sz = vdir_cache->vd_deblk_sz;
+	while (1) {
+		deblk_end.deblk = vdir_cache->vd_deblk[vdir_cache->vd_last.ul];
+		deblk_end.deblk += deblk_sz;
+		while (!is_deblk_end(&vdir_cache->vd_last.p, &deblk_end)) {
+			de = vdir_cache->vd_last.p.de;
+			AuDbg("%.*s, off%lld, i%lu, dt%d\n",
+			      de->de_str.len, de->de_str.name, file->f_pos,
+			      (unsigned long)de->de_ino, de->de_type);
+			err = filldir(dirent, de->de_str.name, de->de_str.len,
+				      file->f_pos, de->de_ino, de->de_type);
+			if (unlikely(err)) {
+				AuTraceErr(err);
+				/* todo: ignore the error caused by udba? */
+				/* return err; */
+				return 0;
+			}
+
+			l = calc_size(de->de_str.len);
+			vdir_cache->vd_last.p.deblk += l;
+			file->f_pos += l;
+		}
+		if (vdir_cache->vd_last.ul < vdir_cache->vd_nblk - 1) {
+			vdir_cache->vd_last.ul++;
+			vdir_cache->vd_last.p.deblk
+				= vdir_cache->vd_deblk[vdir_cache->vd_last.ul];
+			file->f_pos = deblk_sz * vdir_cache->vd_last.ul;
+			continue;
+		}
+		break;
+	}
+
+	/* smp_mb(); */
+	return 0;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/vfsub.c linux-2.6.31.4/fs/aufs/vfsub.c
--- linux-2.6.31.4.orig/fs/aufs/vfsub.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/vfsub.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,740 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sub-routines for VFS
+ */
+
+#include <linux/namei.h>
+#include <linux/security.h>
+#include <linux/splice.h>
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+int vfsub_update_h_iattr(struct path *h_path, int *did)
+{
+	int err;
+	struct kstat st;
+	struct super_block *h_sb;
+
+	/* for remote fs, leave work for its getattr or d_revalidate */
+	/* for bad i_attr fs, handle them in aufs_getattr() */
+	/* still some fs may acquire i_mutex. we need to skip them */
+	err = 0;
+	if (!did)
+		did = &err;
+	h_sb = h_path->dentry->d_sb;
+	*did = (!au_test_fs_remote(h_sb) && au_test_fs_refresh_iattr(h_sb));
+	if (*did)
+		err = vfs_getattr(h_path->mnt, h_path->dentry, &st);
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_IMA
+#error IMA is not supported since it does not work well. Wait for their fixing.
+#endif
+
+struct file *vfsub_filp_open(const char *path, int oflags, int mode)
+{
+	struct file *file;
+
+	lockdep_off();
+	file = filp_open(path, oflags, mode);
+	lockdep_on();
+	if (IS_ERR(file))
+		goto out;
+	vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
+
+ out:
+	return file;
+}
+
+int vfsub_kern_path(const char *name, unsigned int flags, struct path *path)
+{
+	int err;
+
+	/* lockdep_off(); */
+	err = kern_path(name, flags, path);
+	/* lockdep_on(); */
+	if (!err && path->dentry->d_inode)
+		vfsub_update_h_iattr(path, /*did*/NULL); /*ignore*/
+	return err;
+}
+
+struct dentry *vfsub_lookup_one_len(const char *name, struct dentry *parent,
+				    int len)
+{
+	struct path path = {
+		.mnt = NULL
+	};
+
+	IMustLock(parent->d_inode);
+
+	path.dentry = lookup_one_len(name, parent, len);
+	if (IS_ERR(path.dentry))
+		goto out;
+	if (path.dentry->d_inode)
+		vfsub_update_h_iattr(&path, /*did*/NULL); /*ignore*/
+
+ out:
+	return path.dentry;
+}
+
+struct dentry *vfsub_lookup_hash(struct nameidata *nd)
+{
+	struct path path = {
+		.mnt = nd->path.mnt
+	};
+
+	IMustLock(nd->path.dentry->d_inode);
+
+	path.dentry = lookup_hash(nd);
+	if (!IS_ERR(path.dentry) && path.dentry->d_inode)
+		vfsub_update_h_iattr(&path, /*did*/NULL); /*ignore*/
+
+	return path.dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct dentry *vfsub_lock_rename(struct dentry *d1, struct au_hinode *hdir1,
+				 struct dentry *d2, struct au_hinode *hdir2)
+{
+	struct dentry *d;
+
+	lockdep_off();
+	d = lock_rename(d1, d2);
+	lockdep_on();
+	au_hin_suspend(hdir1);
+	if (hdir1 != hdir2)
+		au_hin_suspend(hdir2);
+
+	return d;
+}
+
+void vfsub_unlock_rename(struct dentry *d1, struct au_hinode *hdir1,
+			 struct dentry *d2, struct au_hinode *hdir2)
+{
+	au_hin_resume(hdir1);
+	if (hdir1 != hdir2)
+		au_hin_resume(hdir2);
+	lockdep_off();
+	unlock_rename(d1, d2);
+	lockdep_on();
+}
+
+/* ---------------------------------------------------------------------- */
+
+int vfsub_create(struct inode *dir, struct path *path, int mode)
+{
+	int err;
+	struct dentry *d;
+
+	IMustLock(dir);
+
+	d = path->dentry;
+	path->dentry = d->d_parent;
+	err = security_path_mknod(path, path->dentry, mode, 0);
+	path->dentry = d;
+	if (unlikely(err))
+		goto out;
+
+	if (au_test_fs_null_nd(dir->i_sb))
+		err = vfs_create(dir, path->dentry, mode, NULL);
+	else {
+		struct nameidata h_nd;
+
+		memset(&h_nd, 0, sizeof(h_nd));
+		h_nd.flags = LOOKUP_CREATE;
+		h_nd.intent.open.flags = O_CREAT
+			| vfsub_fmode_to_uint(FMODE_READ);
+		h_nd.intent.open.create_mode = mode;
+		h_nd.path.dentry = path->dentry->d_parent;
+		h_nd.path.mnt = path->mnt;
+		path_get(&h_nd.path);
+		err = vfs_create(dir, path->dentry, mode, &h_nd);
+		path_put(&h_nd.path);
+	}
+
+	if (!err) {
+		struct path tmp = *path;
+		int did;
+
+		vfsub_update_h_iattr(&tmp, &did);
+		if (did) {
+			tmp.dentry = path->dentry->d_parent;
+			vfsub_update_h_iattr(&tmp, /*did*/NULL);
+		}
+		/*ignore*/
+	}
+
+ out:
+	return err;
+}
+
+int vfsub_symlink(struct inode *dir, struct path *path, const char *symname)
+{
+	int err;
+	struct dentry *d;
+
+	IMustLock(dir);
+
+	d = path->dentry;
+	path->dentry = d->d_parent;
+	err = security_path_symlink(path, path->dentry, symname);
+	path->dentry = d;
+	if (unlikely(err))
+		goto out;
+
+	err = vfs_symlink(dir, path->dentry, symname);
+	if (!err) {
+		struct path tmp = *path;
+		int did;
+
+		vfsub_update_h_iattr(&tmp, &did);
+		if (did) {
+			tmp.dentry = path->dentry->d_parent;
+			vfsub_update_h_iattr(&tmp, /*did*/NULL);
+		}
+		/*ignore*/
+	}
+
+ out:
+	return err;
+}
+
+int vfsub_mknod(struct inode *dir, struct path *path, int mode, dev_t dev)
+{
+	int err;
+	struct dentry *d;
+
+	IMustLock(dir);
+
+	d = path->dentry;
+	path->dentry = d->d_parent;
+	err = security_path_mknod(path, path->dentry, mode, dev);
+	path->dentry = d;
+	if (unlikely(err))
+		goto out;
+
+	err = vfs_mknod(dir, path->dentry, mode, dev);
+	if (!err) {
+		struct path tmp = *path;
+		int did;
+
+		vfsub_update_h_iattr(&tmp, &did);
+		if (did) {
+			tmp.dentry = path->dentry->d_parent;
+			vfsub_update_h_iattr(&tmp, /*did*/NULL);
+		}
+		/*ignore*/
+	}
+
+ out:
+	return err;
+}
+
+static int au_test_nlink(struct inode *inode)
+{
+	const unsigned int link_max = UINT_MAX >> 1; /* rough margin */
+
+	if (!au_test_fs_no_limit_nlink(inode->i_sb)
+	    || inode->i_nlink < link_max)
+		return 0;
+	return -EMLINK;
+}
+
+int vfsub_link(struct dentry *src_dentry, struct inode *dir, struct path *path)
+{
+	int err;
+	struct dentry *d;
+
+	IMustLock(dir);
+
+	err = au_test_nlink(src_dentry->d_inode);
+	if (unlikely(err))
+		return err;
+
+	d = path->dentry;
+	path->dentry = d->d_parent;
+	err = security_path_link(src_dentry, path, path->dentry);
+	path->dentry = d;
+	if (unlikely(err))
+		goto out;
+
+	lockdep_off();
+	err = vfs_link(src_dentry, dir, path->dentry);
+	lockdep_on();
+	if (!err) {
+		struct path tmp = *path;
+		int did;
+
+		/* fuse has different memory inode for the same inumber */
+		vfsub_update_h_iattr(&tmp, &did);
+		if (did) {
+			tmp.dentry = path->dentry->d_parent;
+			vfsub_update_h_iattr(&tmp, /*did*/NULL);
+			tmp.dentry = src_dentry;
+			vfsub_update_h_iattr(&tmp, /*did*/NULL);
+		}
+		/*ignore*/
+	}
+
+ out:
+	return err;
+}
+
+int vfsub_rename(struct inode *src_dir, struct dentry *src_dentry,
+		 struct inode *dir, struct path *path)
+{
+	int err;
+	struct path tmp = {
+		.mnt	= path->mnt
+	};
+	struct dentry *d;
+
+	IMustLock(dir);
+	IMustLock(src_dir);
+
+	d = path->dentry;
+	path->dentry = d->d_parent;
+	tmp.dentry = src_dentry->d_parent;
+	err = security_path_rename(&tmp, src_dentry, path, path->dentry);
+	path->dentry = d;
+	if (unlikely(err))
+		goto out;
+
+	lockdep_off();
+	err = vfs_rename(src_dir, src_dentry, dir, path->dentry);
+	lockdep_on();
+	if (!err) {
+		int did;
+
+		tmp.dentry = d->d_parent;
+		vfsub_update_h_iattr(&tmp, &did);
+		if (did) {
+			tmp.dentry = src_dentry;
+			vfsub_update_h_iattr(&tmp, /*did*/NULL);
+			tmp.dentry = src_dentry->d_parent;
+			vfsub_update_h_iattr(&tmp, /*did*/NULL);
+		}
+		/*ignore*/
+	}
+
+ out:
+	return err;
+}
+
+int vfsub_mkdir(struct inode *dir, struct path *path, int mode)
+{
+	int err;
+	struct dentry *d;
+
+	IMustLock(dir);
+
+	d = path->dentry;
+	path->dentry = d->d_parent;
+	err = security_path_mkdir(path, path->dentry, mode);
+	path->dentry = d;
+	if (unlikely(err))
+		goto out;
+
+	err = vfs_mkdir(dir, path->dentry, mode);
+	if (!err) {
+		struct path tmp = *path;
+		int did;
+
+		vfsub_update_h_iattr(&tmp, &did);
+		if (did) {
+			tmp.dentry = path->dentry->d_parent;
+			vfsub_update_h_iattr(&tmp, /*did*/NULL);
+		}
+		/*ignore*/
+	}
+
+ out:
+	return err;
+}
+
+int vfsub_rmdir(struct inode *dir, struct path *path)
+{
+	int err;
+	struct dentry *d;
+
+	IMustLock(dir);
+
+	d = path->dentry;
+	path->dentry = d->d_parent;
+	err = security_path_rmdir(path, path->dentry);
+	path->dentry = d;
+	if (unlikely(err))
+		goto out;
+
+	lockdep_off();
+	err = vfs_rmdir(dir, path->dentry);
+	lockdep_on();
+	if (!err) {
+		struct path tmp = {
+			.dentry	= path->dentry->d_parent,
+			.mnt	= path->mnt
+		};
+
+		vfsub_update_h_iattr(&tmp, /*did*/NULL); /*ignore*/
+	}
+
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+ssize_t vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
+		     loff_t *ppos)
+{
+	ssize_t err;
+
+	err = vfs_read(file, ubuf, count, ppos);
+	if (err >= 0)
+		vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
+	return err;
+}
+
+/* todo: kernel_read()? */
+ssize_t vfsub_read_k(struct file *file, void *kbuf, size_t count,
+		     loff_t *ppos)
+{
+	ssize_t err;
+	mm_segment_t oldfs;
+
+	oldfs = get_fs();
+	set_fs(KERNEL_DS);
+	err = vfsub_read_u(file, (char __user *)kbuf, count, ppos);
+	set_fs(oldfs);
+	return err;
+}
+
+ssize_t vfsub_write_u(struct file *file, const char __user *ubuf, size_t count,
+		      loff_t *ppos)
+{
+	ssize_t err;
+
+	lockdep_off();
+	err = vfs_write(file, ubuf, count, ppos);
+	lockdep_on();
+	if (err >= 0)
+		vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
+	return err;
+}
+
+ssize_t vfsub_write_k(struct file *file, void *kbuf, size_t count, loff_t *ppos)
+{
+	ssize_t err;
+	mm_segment_t oldfs;
+
+	oldfs = get_fs();
+	set_fs(KERNEL_DS);
+	err = vfsub_write_u(file, (const char __user *)kbuf, count, ppos);
+	set_fs(oldfs);
+	return err;
+}
+
+int vfsub_readdir(struct file *file, filldir_t filldir, void *arg)
+{
+	int err;
+
+	lockdep_off();
+	err = vfs_readdir(file, filldir, arg);
+	lockdep_on();
+	if (err >= 0)
+		vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
+	return err;
+}
+
+long vfsub_splice_to(struct file *in, loff_t *ppos,
+		     struct pipe_inode_info *pipe, size_t len,
+		     unsigned int flags)
+{
+	long err;
+
+	lockdep_off();
+	err = do_splice_to(in, ppos, pipe, len, flags);
+	lockdep_on();
+	if (err >= 0)
+		vfsub_update_h_iattr(&in->f_path, /*did*/NULL); /*ignore*/
+	return err;
+}
+
+long vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
+		       loff_t *ppos, size_t len, unsigned int flags)
+{
+	long err;
+
+	lockdep_off();
+	err = do_splice_from(pipe, out, ppos, len, flags);
+	lockdep_on();
+	if (err >= 0)
+		vfsub_update_h_iattr(&out->f_path, /*did*/NULL); /*ignore*/
+	return err;
+}
+
+/* cf. open.c:do_sys_truncate() and do_sys_ftruncate() */
+int vfsub_trunc(struct path *h_path, loff_t length, unsigned int attr,
+		struct file *h_file)
+{
+	int err;
+	struct inode *h_inode;
+
+	h_inode = h_path->dentry->d_inode;
+	if (!h_file) {
+		err = mnt_want_write(h_path->mnt);
+		if (err)
+			goto out;
+		err = inode_permission(h_inode, MAY_WRITE);
+		if (err)
+			goto out_mnt;
+		err = get_write_access(h_inode);
+		if (err)
+			goto out_mnt;
+		err = break_lease(h_inode, vfsub_fmode_to_uint(FMODE_WRITE));
+		if (err)
+			goto out_inode;
+	}
+
+	err = locks_verify_truncate(h_inode, h_file, length);
+	if (!err)
+		err = security_path_truncate(h_path, length, attr);
+	if (!err) {
+		lockdep_off();
+		err = do_truncate(h_path->dentry, length, attr, h_file);
+		lockdep_on();
+	}
+
+ out_inode:
+	if (!h_file)
+		put_write_access(h_inode);
+ out_mnt:
+	if (!h_file)
+		mnt_drop_write(h_path->mnt);
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_vfsub_mkdir_args {
+	int *errp;
+	struct inode *dir;
+	struct path *path;
+	int mode;
+};
+
+static void au_call_vfsub_mkdir(void *args)
+{
+	struct au_vfsub_mkdir_args *a = args;
+	*a->errp = vfsub_mkdir(a->dir, a->path, a->mode);
+}
+
+int vfsub_sio_mkdir(struct inode *dir, struct path *path, int mode)
+{
+	int err, do_sio, wkq_err;
+
+	do_sio = au_test_h_perm_sio(dir, MAY_EXEC | MAY_WRITE);
+	if (!do_sio)
+		err = vfsub_mkdir(dir, path, mode);
+	else {
+		struct au_vfsub_mkdir_args args = {
+			.errp	= &err,
+			.dir	= dir,
+			.path	= path,
+			.mode	= mode
+		};
+		wkq_err = au_wkq_wait(au_call_vfsub_mkdir, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	return err;
+}
+
+struct au_vfsub_rmdir_args {
+	int *errp;
+	struct inode *dir;
+	struct path *path;
+};
+
+static void au_call_vfsub_rmdir(void *args)
+{
+	struct au_vfsub_rmdir_args *a = args;
+	*a->errp = vfsub_rmdir(a->dir, a->path);
+}
+
+int vfsub_sio_rmdir(struct inode *dir, struct path *path)
+{
+	int err, do_sio, wkq_err;
+
+	do_sio = au_test_h_perm_sio(dir, MAY_EXEC | MAY_WRITE);
+	if (!do_sio)
+		err = vfsub_rmdir(dir, path);
+	else {
+		struct au_vfsub_rmdir_args args = {
+			.errp	= &err,
+			.dir	= dir,
+			.path	= path
+		};
+		wkq_err = au_wkq_wait(au_call_vfsub_rmdir, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct notify_change_args {
+	int *errp;
+	struct path *path;
+	struct iattr *ia;
+};
+
+static void call_notify_change(void *args)
+{
+	struct notify_change_args *a = args;
+	struct inode *h_inode;
+
+	h_inode = a->path->dentry->d_inode;
+	IMustLock(h_inode);
+
+	*a->errp = -EPERM;
+	if (!IS_IMMUTABLE(h_inode) && !IS_APPEND(h_inode)) {
+		lockdep_off();
+		*a->errp = notify_change(a->path->dentry, a->ia);
+		lockdep_on();
+		if (!*a->errp)
+			vfsub_update_h_iattr(a->path, /*did*/NULL); /*ignore*/
+	}
+	AuTraceErr(*a->errp);
+}
+
+int vfsub_notify_change(struct path *path, struct iattr *ia)
+{
+	int err;
+	struct notify_change_args args = {
+		.errp	= &err,
+		.path	= path,
+		.ia	= ia
+	};
+
+	call_notify_change(&args);
+
+	return err;
+}
+
+int vfsub_sio_notify_change(struct path *path, struct iattr *ia)
+{
+	int err, wkq_err;
+	struct notify_change_args args = {
+		.errp	= &err,
+		.path	= path,
+		.ia	= ia
+	};
+
+	wkq_err = au_wkq_wait(call_notify_change, &args);
+	if (unlikely(wkq_err))
+		err = wkq_err;
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct unlink_args {
+	int *errp;
+	struct inode *dir;
+	struct path *path;
+};
+
+static void call_unlink(void *args)
+{
+	struct unlink_args *a = args;
+	struct dentry *d = a->path->dentry;
+	struct inode *h_inode;
+	const int stop_sillyrename = (au_test_nfs(d->d_sb)
+				      && atomic_read(&d->d_count) == 1);
+
+	IMustLock(a->dir);
+
+	a->path->dentry = d->d_parent;
+	*a->errp = security_path_unlink(a->path, d);
+	a->path->dentry = d;
+	if (unlikely(*a->errp))
+		return;
+
+	if (!stop_sillyrename)
+		dget(d);
+	h_inode = d->d_inode;
+	if (h_inode)
+		atomic_inc(&h_inode->i_count);
+
+	lockdep_off();
+	*a->errp = vfs_unlink(a->dir, d);
+	lockdep_on();
+	if (!*a->errp) {
+		struct path tmp = {
+			.dentry = d->d_parent,
+			.mnt	= a->path->mnt
+		};
+		vfsub_update_h_iattr(&tmp, /*did*/NULL); /*ignore*/
+	}
+
+	if (!stop_sillyrename)
+		dput(d);
+	if (h_inode)
+		iput(h_inode);
+
+	AuTraceErr(*a->errp);
+}
+
+/*
+ * @dir: must be locked.
+ * @dentry: target dentry.
+ */
+int vfsub_unlink(struct inode *dir, struct path *path, int force)
+{
+	int err;
+	struct unlink_args args = {
+		.errp	= &err,
+		.dir	= dir,
+		.path	= path
+	};
+
+	if (!force)
+		call_unlink(&args);
+	else {
+		int wkq_err;
+
+		wkq_err = au_wkq_wait(call_unlink, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/vfsub.h linux-2.6.31.4/fs/aufs/vfsub.h
--- linux-2.6.31.4.orig/fs/aufs/vfsub.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/vfsub.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,172 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sub-routines for VFS
+ */
+
+#ifndef __AUFS_VFSUB_H__
+#define __AUFS_VFSUB_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/fs_stack.h>
+
+/* ---------------------------------------------------------------------- */
+
+/* lock subclass for lower inode */
+/* default MAX_LOCKDEP_SUBCLASSES(8) is not enough */
+/* reduce? gave up. */
+enum {
+	AuLsc_I_Begin = I_MUTEX_QUOTA, /* 4 */
+	AuLsc_I_PARENT,		/* lower inode, parent first */
+	AuLsc_I_PARENT2,	/* copyup dirs */
+	AuLsc_I_PARENT3,	/* copyup wh */
+	AuLsc_I_CHILD,
+	AuLsc_I_CHILD2,
+	AuLsc_I_End
+};
+
+/* to debug easier, do not make them inlined functions */
+#define MtxMustLock(mtx)	AuDebugOn(!mutex_is_locked(mtx))
+#define IMustLock(i)		MtxMustLock(&(i)->i_mutex)
+
+/* ---------------------------------------------------------------------- */
+
+static inline void vfsub_copy_inode_size(struct inode *inode,
+					 struct inode *h_inode)
+{
+	spin_lock(&inode->i_lock);
+	fsstack_copy_inode_size(inode, h_inode);
+	spin_unlock(&inode->i_lock);
+}
+
+int vfsub_update_h_iattr(struct path *h_path, int *did);
+struct file *vfsub_filp_open(const char *path, int oflags, int mode);
+int vfsub_kern_path(const char *name, unsigned int flags, struct path *path);
+struct dentry *vfsub_lookup_one_len(const char *name, struct dentry *parent,
+				    int len);
+struct dentry *vfsub_lookup_hash(struct nameidata *nd);
+
+/* ---------------------------------------------------------------------- */
+
+struct au_hinode;
+struct dentry *vfsub_lock_rename(struct dentry *d1, struct au_hinode *hdir1,
+				 struct dentry *d2, struct au_hinode *hdir2);
+void vfsub_unlock_rename(struct dentry *d1, struct au_hinode *hdir1,
+			 struct dentry *d2, struct au_hinode *hdir2);
+
+int vfsub_create(struct inode *dir, struct path *path, int mode);
+int vfsub_symlink(struct inode *dir, struct path *path,
+		  const char *symname);
+int vfsub_mknod(struct inode *dir, struct path *path, int mode, dev_t dev);
+int vfsub_link(struct dentry *src_dentry, struct inode *dir,
+	       struct path *path);
+int vfsub_rename(struct inode *src_hdir, struct dentry *src_dentry,
+		 struct inode *hdir, struct path *path);
+int vfsub_mkdir(struct inode *dir, struct path *path, int mode);
+int vfsub_rmdir(struct inode *dir, struct path *path);
+
+/* ---------------------------------------------------------------------- */
+
+ssize_t vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
+		     loff_t *ppos);
+ssize_t vfsub_read_k(struct file *file, void *kbuf, size_t count,
+			loff_t *ppos);
+ssize_t vfsub_write_u(struct file *file, const char __user *ubuf, size_t count,
+		      loff_t *ppos);
+ssize_t vfsub_write_k(struct file *file, void *kbuf, size_t count,
+		      loff_t *ppos);
+int vfsub_readdir(struct file *file, filldir_t filldir, void *arg);
+
+static inline void vfsub_file_accessed(struct file *h_file)
+{
+	file_accessed(h_file);
+	vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL); /*ignore*/
+}
+
+static inline void vfsub_touch_atime(struct vfsmount *h_mnt,
+				     struct dentry *h_dentry)
+{
+	struct path h_path = {
+		.dentry	= h_dentry,
+		.mnt	= h_mnt
+	};
+	touch_atime(h_mnt, h_dentry);
+	vfsub_update_h_iattr(&h_path, /*did*/NULL); /*ignore*/
+}
+
+long vfsub_splice_to(struct file *in, loff_t *ppos,
+		     struct pipe_inode_info *pipe, size_t len,
+		     unsigned int flags);
+long vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
+		       loff_t *ppos, size_t len, unsigned int flags);
+int vfsub_trunc(struct path *h_path, loff_t length, unsigned int attr,
+		struct file *h_file);
+
+/* ---------------------------------------------------------------------- */
+
+static inline loff_t vfsub_llseek(struct file *file, loff_t offset, int origin)
+{
+	loff_t err;
+
+	lockdep_off();
+	err = vfs_llseek(file, offset, origin);
+	lockdep_on();
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* dirty workaround for strict type of fmode_t */
+union vfsub_fmu {
+	fmode_t fm;
+	unsigned int ui;
+};
+
+static inline unsigned int vfsub_fmode_to_uint(fmode_t fm)
+{
+	union vfsub_fmu u = {
+		.fm = fm
+	};
+
+	BUILD_BUG_ON(sizeof(u.fm) != sizeof(u.ui));
+
+	return u.ui;
+}
+
+static inline fmode_t vfsub_uint_to_fmode(unsigned int ui)
+{
+	union vfsub_fmu u = {
+		.ui = ui
+	};
+
+	return u.fm;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int vfsub_sio_mkdir(struct inode *dir, struct path *path, int mode);
+int vfsub_sio_rmdir(struct inode *dir, struct path *path);
+int vfsub_sio_notify_change(struct path *path, struct iattr *ia);
+int vfsub_notify_change(struct path *path, struct iattr *ia);
+int vfsub_unlink(struct inode *dir, struct path *path, int force);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_VFSUB_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/wbr_policy.c linux-2.6.31.4/fs/aufs/wbr_policy.c
--- linux-2.6.31.4.orig/fs/aufs/wbr_policy.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/wbr_policy.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,641 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * policies for selecting one among multiple writable branches
+ */
+
+#include <linux/statfs.h>
+#include "aufs.h"
+
+/* subset of cpup_attr() */
+static noinline_for_stack
+int au_cpdown_attr(struct path *h_path, struct dentry *h_src)
+{
+	int err, sbits;
+	struct iattr ia;
+	struct inode *h_isrc;
+
+	h_isrc = h_src->d_inode;
+	ia.ia_valid = ATTR_FORCE | ATTR_MODE | ATTR_UID | ATTR_GID;
+	ia.ia_mode = h_isrc->i_mode;
+	ia.ia_uid = h_isrc->i_uid;
+	ia.ia_gid = h_isrc->i_gid;
+	sbits = !!(ia.ia_mode & (S_ISUID | S_ISGID));
+	au_cpup_attr_flags(h_path->dentry->d_inode, h_isrc);
+	err = vfsub_sio_notify_change(h_path, &ia);
+
+	/* is this nfs only? */
+	if (!err && sbits && au_test_nfs(h_path->dentry->d_sb)) {
+		ia.ia_valid = ATTR_FORCE | ATTR_MODE;
+		ia.ia_mode = h_isrc->i_mode;
+		err = vfsub_sio_notify_change(h_path, &ia);
+	}
+
+	return err;
+}
+
+#define AuCpdown_PARENT_OPQ	1
+#define AuCpdown_WHED		(1 << 1)
+#define AuCpdown_MADE_DIR	(1 << 2)
+#define AuCpdown_DIROPQ		(1 << 3)
+#define au_ftest_cpdown(flags, name)	((flags) & AuCpdown_##name)
+#define au_fset_cpdown(flags, name)	{ (flags) |= AuCpdown_##name; }
+#define au_fclr_cpdown(flags, name)	{ (flags) &= ~AuCpdown_##name; }
+
+struct au_cpdown_dir_args {
+	struct dentry *parent;
+	unsigned int flags;
+};
+
+static int au_cpdown_dir_opq(struct dentry *dentry, aufs_bindex_t bdst,
+			     struct au_cpdown_dir_args *a)
+{
+	int err;
+	struct dentry *opq_dentry;
+
+	opq_dentry = au_diropq_create(dentry, bdst);
+	err = PTR_ERR(opq_dentry);
+	if (IS_ERR(opq_dentry))
+		goto out;
+	dput(opq_dentry);
+	au_fset_cpdown(a->flags, DIROPQ);
+
+ out:
+	return err;
+}
+
+static int au_cpdown_dir_wh(struct dentry *dentry, struct dentry *h_parent,
+			    struct inode *dir, aufs_bindex_t bdst)
+{
+	int err;
+	struct path h_path;
+	struct au_branch *br;
+
+	br = au_sbr(dentry->d_sb, bdst);
+	h_path.dentry = au_wh_lkup(h_parent, &dentry->d_name, br);
+	err = PTR_ERR(h_path.dentry);
+	if (IS_ERR(h_path.dentry))
+		goto out;
+
+	err = 0;
+	if (h_path.dentry->d_inode) {
+		h_path.mnt = br->br_mnt;
+		err = au_wh_unlink_dentry(au_h_iptr(dir, bdst), &h_path,
+					  dentry);
+	}
+	dput(h_path.dentry);
+
+ out:
+	return err;
+}
+
+static int au_cpdown_dir(struct dentry *dentry, aufs_bindex_t bdst,
+			 struct dentry *h_parent, void *arg)
+{
+	int err, rerr;
+	aufs_bindex_t bend, bopq, bstart;
+	unsigned char parent_opq;
+	struct path h_path;
+	struct dentry *parent;
+	struct inode *h_dir, *h_inode, *inode, *dir;
+	struct au_cpdown_dir_args *args = arg;
+
+	bstart = au_dbstart(dentry);
+	/* dentry is di-locked */
+	parent = dget_parent(dentry);
+	dir = parent->d_inode;
+	h_dir = h_parent->d_inode;
+	AuDebugOn(h_dir != au_h_iptr(dir, bdst));
+	IMustLock(h_dir);
+
+	err = au_lkup_neg(dentry, bdst);
+	if (unlikely(err < 0))
+		goto out;
+	h_path.dentry = au_h_dptr(dentry, bdst);
+	h_path.mnt = au_sbr_mnt(dentry->d_sb, bdst);
+	err = vfsub_sio_mkdir(au_h_iptr(dir, bdst), &h_path,
+			      S_IRWXU | S_IRUGO | S_IXUGO);
+	if (unlikely(err))
+		goto out_put;
+	au_fset_cpdown(args->flags, MADE_DIR);
+
+	bend = au_dbend(dentry);
+	bopq = au_dbdiropq(dentry);
+	au_fclr_cpdown(args->flags, WHED);
+	au_fclr_cpdown(args->flags, DIROPQ);
+	if (au_dbwh(dentry) == bdst)
+		au_fset_cpdown(args->flags, WHED);
+	if (!au_ftest_cpdown(args->flags, PARENT_OPQ) && bopq <= bdst)
+		au_fset_cpdown(args->flags, PARENT_OPQ);
+	parent_opq = (au_ftest_cpdown(args->flags, PARENT_OPQ)
+		      && args->parent == dentry);
+	h_inode = h_path.dentry->d_inode;
+	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+	if (au_ftest_cpdown(args->flags, WHED)) {
+		err = au_cpdown_dir_opq(dentry, bdst, args);
+		if (unlikely(err)) {
+			mutex_unlock(&h_inode->i_mutex);
+			goto out_dir;
+		}
+	}
+
+	err = au_cpdown_attr(&h_path, au_h_dptr(dentry, bstart));
+	mutex_unlock(&h_inode->i_mutex);
+	if (unlikely(err))
+		goto out_opq;
+
+	if (au_ftest_cpdown(args->flags, WHED)) {
+		err = au_cpdown_dir_wh(dentry, h_parent, dir, bdst);
+		if (unlikely(err))
+			goto out_opq;
+	}
+
+	inode = dentry->d_inode;
+	if (au_ibend(inode) < bdst)
+		au_set_ibend(inode, bdst);
+	au_set_h_iptr(inode, bdst, au_igrab(h_inode),
+		      au_hi_flags(inode, /*isdir*/1));
+	goto out; /* success */
+
+	/* revert */
+ out_opq:
+	if (au_ftest_cpdown(args->flags, DIROPQ)) {
+		mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+		rerr = au_diropq_remove(dentry, bdst);
+		mutex_unlock(&h_inode->i_mutex);
+		if (unlikely(rerr)) {
+			AuIOErr("failed removing diropq for %.*s b%d (%d)\n",
+				AuDLNPair(dentry), bdst, rerr);
+			err = -EIO;
+			goto out;
+		}
+	}
+ out_dir:
+	if (au_ftest_cpdown(args->flags, MADE_DIR)) {
+		rerr = vfsub_sio_rmdir(au_h_iptr(dir, bdst), &h_path);
+		if (unlikely(rerr)) {
+			AuIOErr("failed removing %.*s b%d (%d)\n",
+				AuDLNPair(dentry), bdst, rerr);
+			err = -EIO;
+		}
+	}
+ out_put:
+	au_set_h_dptr(dentry, bdst, NULL);
+	if (au_dbend(dentry) == bdst)
+		au_update_dbend(dentry);
+ out:
+	dput(parent);
+	return err;
+}
+
+int au_cpdown_dirs(struct dentry *dentry, aufs_bindex_t bdst)
+{
+	int err;
+	struct au_cpdown_dir_args args = {
+		.parent	= dget_parent(dentry),
+		.flags	= 0
+	};
+
+	err = au_cp_dirs(dentry, bdst, au_cpdown_dir, &args);
+	dput(args.parent);
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* policies for create */
+
+static int au_wbr_bu(struct super_block *sb, aufs_bindex_t bindex)
+{
+	for (; bindex >= 0; bindex--)
+		if (!au_br_rdonly(au_sbr(sb, bindex)))
+			return bindex;
+	return -EROFS;
+}
+
+/* top down parent */
+static int au_wbr_create_tdp(struct dentry *dentry, int isdir __maybe_unused)
+{
+	int err;
+	aufs_bindex_t bstart, bindex;
+	struct super_block *sb;
+	struct dentry *parent, *h_parent;
+
+	sb = dentry->d_sb;
+	bstart = au_dbstart(dentry);
+	err = bstart;
+	if (!au_br_rdonly(au_sbr(sb, bstart)))
+		goto out;
+
+	err = -EROFS;
+	parent = dget_parent(dentry);
+	for (bindex = au_dbstart(parent); bindex < bstart; bindex++) {
+		h_parent = au_h_dptr(parent, bindex);
+		if (!h_parent || !h_parent->d_inode)
+			continue;
+
+		if (!au_br_rdonly(au_sbr(sb, bindex))) {
+			err = bindex;
+			break;
+		}
+	}
+	dput(parent);
+
+	/* bottom up here */
+	if (unlikely(err < 0))
+		err = au_wbr_bu(sb, bstart - 1);
+
+ out:
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* an exception for the policy other than tdp */
+static int au_wbr_create_exp(struct dentry *dentry)
+{
+	int err;
+	aufs_bindex_t bwh, bdiropq;
+	struct dentry *parent;
+
+	err = -1;
+	bwh = au_dbwh(dentry);
+	parent = dget_parent(dentry);
+	bdiropq = au_dbdiropq(parent);
+	if (bwh >= 0) {
+		if (bdiropq >= 0)
+			err = min(bdiropq, bwh);
+		else
+			err = bwh;
+		AuDbg("%d\n", err);
+	} else if (bdiropq >= 0) {
+		err = bdiropq;
+		AuDbg("%d\n", err);
+	}
+	dput(parent);
+
+	if (err >= 0 && au_br_rdonly(au_sbr(dentry->d_sb, err)))
+		err = -1;
+
+	AuDbg("%d\n", err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* round robin */
+static int au_wbr_create_init_rr(struct super_block *sb)
+{
+	int err;
+
+	err = au_wbr_bu(sb, au_sbend(sb));
+	atomic_set(&au_sbi(sb)->si_wbr_rr_next, -err); /* less important */
+	/* smp_mb(); */
+
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+static int au_wbr_create_rr(struct dentry *dentry, int isdir)
+{
+	int err, nbr;
+	unsigned int u;
+	aufs_bindex_t bindex, bend;
+	struct super_block *sb;
+	atomic_t *next;
+
+	err = au_wbr_create_exp(dentry);
+	if (err >= 0)
+		goto out;
+
+	sb = dentry->d_sb;
+	next = &au_sbi(sb)->si_wbr_rr_next;
+	bend = au_sbend(sb);
+	nbr = bend + 1;
+	for (bindex = 0; bindex <= bend; bindex++) {
+		if (!isdir) {
+			err = atomic_dec_return(next) + 1;
+			/* modulo for 0 is meaningless */
+			if (unlikely(!err))
+				err = atomic_dec_return(next) + 1;
+		} else
+			err = atomic_read(next);
+		AuDbg("%d\n", err);
+		u = err;
+		err = u % nbr;
+		AuDbg("%d\n", err);
+		if (!au_br_rdonly(au_sbr(sb, err)))
+			break;
+		err = -EROFS;
+	}
+
+ out:
+	AuDbg("%d\n", err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* most free space */
+static void au_mfs(struct dentry *dentry)
+{
+	struct super_block *sb;
+	struct au_branch *br;
+	struct au_wbr_mfs *mfs;
+	aufs_bindex_t bindex, bend;
+	int err;
+	unsigned long long b, bavail;
+	/* reduce the stack usage */
+	struct kstatfs *st;
+
+	st = kmalloc(sizeof(*st), GFP_NOFS);
+	if (unlikely(!st)) {
+		AuWarn1("failed updating mfs(%d), ignored\n", -ENOMEM);
+		return;
+	}
+
+	bavail = 0;
+	sb = dentry->d_sb;
+	mfs = &au_sbi(sb)->si_wbr_mfs;
+	MtxMustLock(&mfs->mfs_lock);
+	mfs->mfs_bindex = -EROFS;
+	mfs->mfsrr_bytes = 0;
+	bend = au_sbend(sb);
+	for (bindex = 0; bindex <= bend; bindex++) {
+		br = au_sbr(sb, bindex);
+		if (au_br_rdonly(br))
+			continue;
+
+		/* sb->s_root for NFS is unreliable */
+		err = vfs_statfs(br->br_mnt->mnt_root, st);
+		if (unlikely(err)) {
+			AuWarn1("failed statfs, b%d, %d\n", bindex, err);
+			continue;
+		}
+
+		/* when the available size is equal, select the lower one */
+		BUILD_BUG_ON(sizeof(b) < sizeof(st->f_bavail)
+			     || sizeof(b) < sizeof(st->f_bsize));
+		b = st->f_bavail * st->f_bsize;
+		br->br_wbr->wbr_bytes = b;
+		if (b >= bavail) {
+			bavail = b;
+			mfs->mfs_bindex = bindex;
+			mfs->mfs_jiffy = jiffies;
+		}
+	}
+
+	mfs->mfsrr_bytes = bavail;
+	AuDbg("b%d\n", mfs->mfs_bindex);
+	kfree(st);
+}
+
+static int au_wbr_create_mfs(struct dentry *dentry, int isdir __maybe_unused)
+{
+	int err;
+	struct super_block *sb;
+	struct au_wbr_mfs *mfs;
+
+	err = au_wbr_create_exp(dentry);
+	if (err >= 0)
+		goto out;
+
+	sb = dentry->d_sb;
+	mfs = &au_sbi(sb)->si_wbr_mfs;
+	mutex_lock(&mfs->mfs_lock);
+	if (time_after(jiffies, mfs->mfs_jiffy + mfs->mfs_expire)
+	    || mfs->mfs_bindex < 0
+	    || au_br_rdonly(au_sbr(sb, mfs->mfs_bindex)))
+		au_mfs(dentry);
+	mutex_unlock(&mfs->mfs_lock);
+	err = mfs->mfs_bindex;
+
+ out:
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+static int au_wbr_create_init_mfs(struct super_block *sb)
+{
+	struct au_wbr_mfs *mfs;
+
+	mfs = &au_sbi(sb)->si_wbr_mfs;
+	mutex_init(&mfs->mfs_lock);
+	mfs->mfs_jiffy = 0;
+	mfs->mfs_bindex = -EROFS;
+
+	return 0;
+}
+
+static int au_wbr_create_fin_mfs(struct super_block *sb __maybe_unused)
+{
+	mutex_destroy(&au_sbi(sb)->si_wbr_mfs.mfs_lock);
+	return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* most free space and then round robin */
+static int au_wbr_create_mfsrr(struct dentry *dentry, int isdir)
+{
+	int err;
+	struct au_wbr_mfs *mfs;
+
+	err = au_wbr_create_mfs(dentry, isdir);
+	if (err >= 0) {
+		mfs = &au_sbi(dentry->d_sb)->si_wbr_mfs;
+		mutex_lock(&mfs->mfs_lock);
+		if (mfs->mfsrr_bytes < mfs->mfsrr_watermark)
+			err = au_wbr_create_rr(dentry, isdir);
+		mutex_unlock(&mfs->mfs_lock);
+	}
+
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+static int au_wbr_create_init_mfsrr(struct super_block *sb)
+{
+	int err;
+
+	au_wbr_create_init_mfs(sb); /* ignore */
+	err = au_wbr_create_init_rr(sb);
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* top down parent and most free space */
+static int au_wbr_create_pmfs(struct dentry *dentry, int isdir)
+{
+	int err, e2;
+	unsigned long long b;
+	aufs_bindex_t bindex, bstart, bend;
+	struct super_block *sb;
+	struct dentry *parent, *h_parent;
+	struct au_branch *br;
+
+	err = au_wbr_create_tdp(dentry, isdir);
+	if (unlikely(err < 0))
+		goto out;
+	parent = dget_parent(dentry);
+	bstart = au_dbstart(parent);
+	bend = au_dbtaildir(parent);
+	if (bstart == bend)
+		goto out_parent; /* success */
+
+	e2 = au_wbr_create_mfs(dentry, isdir);
+	if (e2 < 0)
+		goto out_parent; /* success */
+
+	/* when the available size is equal, select upper one */
+	sb = dentry->d_sb;
+	br = au_sbr(sb, err);
+	b = br->br_wbr->wbr_bytes;
+	AuDbg("b%d, %llu\n", err, b);
+
+	for (bindex = bstart; bindex <= bend; bindex++) {
+		h_parent = au_h_dptr(parent, bindex);
+		if (!h_parent || !h_parent->d_inode)
+			continue;
+
+		br = au_sbr(sb, bindex);
+		if (!au_br_rdonly(br) && br->br_wbr->wbr_bytes > b) {
+			b = br->br_wbr->wbr_bytes;
+			err = bindex;
+			AuDbg("b%d, %llu\n", err, b);
+		}
+	}
+
+ out_parent:
+	dput(parent);
+ out:
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* policies for copyup */
+
+/* top down parent */
+static int au_wbr_copyup_tdp(struct dentry *dentry)
+{
+	return au_wbr_create_tdp(dentry, /*isdir, anything is ok*/0);
+}
+
+/* bottom up parent */
+static int au_wbr_copyup_bup(struct dentry *dentry)
+{
+	int err;
+	aufs_bindex_t bindex, bstart;
+	struct dentry *parent, *h_parent;
+	struct super_block *sb;
+
+	err = -EROFS;
+	sb = dentry->d_sb;
+	parent = dget_parent(dentry);
+	bstart = au_dbstart(parent);
+	for (bindex = au_dbstart(dentry); bindex >= bstart; bindex--) {
+		h_parent = au_h_dptr(parent, bindex);
+		if (!h_parent || !h_parent->d_inode)
+			continue;
+
+		if (!au_br_rdonly(au_sbr(sb, bindex))) {
+			err = bindex;
+			break;
+		}
+	}
+	dput(parent);
+
+	/* bottom up here */
+	if (unlikely(err < 0))
+		err = au_wbr_bu(sb, bstart - 1);
+
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+/* bottom up */
+static int au_wbr_copyup_bu(struct dentry *dentry)
+{
+	int err;
+
+	err = au_wbr_bu(dentry->d_sb, au_dbstart(dentry));
+
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_wbr_copyup_operations au_wbr_copyup_ops[] = {
+	[AuWbrCopyup_TDP] = {
+		.copyup	= au_wbr_copyup_tdp
+	},
+	[AuWbrCopyup_BUP] = {
+		.copyup	= au_wbr_copyup_bup
+	},
+	[AuWbrCopyup_BU] = {
+		.copyup	= au_wbr_copyup_bu
+	}
+};
+
+struct au_wbr_create_operations au_wbr_create_ops[] = {
+	[AuWbrCreate_TDP] = {
+		.create	= au_wbr_create_tdp
+	},
+	[AuWbrCreate_RR] = {
+		.create	= au_wbr_create_rr,
+		.init	= au_wbr_create_init_rr
+	},
+	[AuWbrCreate_MFS] = {
+		.create	= au_wbr_create_mfs,
+		.init	= au_wbr_create_init_mfs,
+		.fin	= au_wbr_create_fin_mfs
+	},
+	[AuWbrCreate_MFSV] = {
+		.create	= au_wbr_create_mfs,
+		.init	= au_wbr_create_init_mfs,
+		.fin	= au_wbr_create_fin_mfs
+	},
+	[AuWbrCreate_MFSRR] = {
+		.create	= au_wbr_create_mfsrr,
+		.init	= au_wbr_create_init_mfsrr,
+		.fin	= au_wbr_create_fin_mfs
+	},
+	[AuWbrCreate_MFSRRV] = {
+		.create	= au_wbr_create_mfsrr,
+		.init	= au_wbr_create_init_mfsrr,
+		.fin	= au_wbr_create_fin_mfs
+	},
+	[AuWbrCreate_PMFS] = {
+		.create	= au_wbr_create_pmfs,
+		.init	= au_wbr_create_init_mfs,
+		.fin	= au_wbr_create_fin_mfs
+	},
+	[AuWbrCreate_PMFSV] = {
+		.create	= au_wbr_create_pmfs,
+		.init	= au_wbr_create_init_mfs,
+		.fin	= au_wbr_create_fin_mfs
+	}
+};
diff -Nur linux-2.6.31.4.orig/fs/aufs/whout.c linux-2.6.31.4/fs/aufs/whout.c
--- linux-2.6.31.4.orig/fs/aufs/whout.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/whout.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,1048 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * whiteout for logical deletion and opaque directory
+ */
+
+#include <linux/fs.h>
+#include "aufs.h"
+
+#define WH_MASK			S_IRUGO
+
+/*
+ * If a directory contains this file, then it is opaque.  We start with the
+ * .wh. flag so that it is blocked by lookup.
+ */
+static struct qstr diropq_name = {
+	.name = AUFS_WH_DIROPQ,
+	.len = sizeof(AUFS_WH_DIROPQ) - 1
+};
+
+/*
+ * generate whiteout name, which is NOT terminated by NULL.
+ * @name: original d_name.name
+ * @len: original d_name.len
+ * @wh: whiteout qstr
+ * returns zero when succeeds, otherwise error.
+ * succeeded value as wh->name should be freed by kfree().
+ */
+int au_wh_name_alloc(struct qstr *wh, const struct qstr *name)
+{
+	char *p;
+
+	if (unlikely(name->len > PATH_MAX - AUFS_WH_PFX_LEN))
+		return -ENAMETOOLONG;
+
+	wh->len = name->len + AUFS_WH_PFX_LEN;
+	p = kmalloc(wh->len, GFP_NOFS);
+	wh->name = p;
+	if (p) {
+		memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
+		memcpy(p + AUFS_WH_PFX_LEN, name->name, name->len);
+		/* smp_mb(); */
+		return 0;
+	}
+	return -ENOMEM;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * test if the @wh_name exists under @h_parent.
+ * @try_sio specifies the necessary of super-io.
+ */
+int au_wh_test(struct dentry *h_parent, struct qstr *wh_name,
+	       struct au_branch *br, int try_sio)
+{
+	int err;
+	struct dentry *wh_dentry;
+	struct inode *h_dir;
+
+	h_dir = h_parent->d_inode;
+	if (!try_sio)
+		wh_dentry = au_lkup_one(wh_name, h_parent, br, /*nd*/NULL);
+	else
+		wh_dentry = au_sio_lkup_one(wh_name, h_parent, br);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry))
+		goto out;
+
+	err = 0;
+	if (!wh_dentry->d_inode)
+		goto out_wh; /* success */
+
+	err = 1;
+	if (S_ISREG(wh_dentry->d_inode->i_mode))
+		goto out_wh; /* success */
+
+	err = -EIO;
+	AuIOErr("%.*s Invalid whiteout entry type 0%o.\n",
+		AuDLNPair(wh_dentry), wh_dentry->d_inode->i_mode);
+
+ out_wh:
+	dput(wh_dentry);
+ out:
+	return err;
+}
+
+/*
+ * test if the @h_dentry sets opaque or not.
+ */
+int au_diropq_test(struct dentry *h_dentry, struct au_branch *br)
+{
+	int err;
+	struct inode *h_dir;
+
+	h_dir = h_dentry->d_inode;
+	err = au_wh_test(h_dentry, &diropq_name, br,
+			 au_test_h_perm_sio(h_dir, MAY_EXEC));
+	return err;
+}
+
+/*
+ * returns a negative dentry whose name is unique and temporary.
+ */
+struct dentry *au_whtmp_lkup(struct dentry *h_parent, struct au_branch *br,
+			     struct qstr *prefix)
+{
+#define HEX_LEN	4
+	struct dentry *dentry;
+	int i;
+	char defname[AUFS_WH_PFX_LEN * 2 + DNAME_INLINE_LEN_MIN + 1
+		     + HEX_LEN + 1], *name, *p;
+	static unsigned short cnt;
+	struct qstr qs;
+
+	name = defname;
+	qs.len = sizeof(defname) - DNAME_INLINE_LEN_MIN + prefix->len - 1;
+	if (unlikely(prefix->len > DNAME_INLINE_LEN_MIN)) {
+		dentry = ERR_PTR(-ENAMETOOLONG);
+		if (unlikely(qs.len >= PATH_MAX))
+			goto out;
+		dentry = ERR_PTR(-ENOMEM);
+		name = kmalloc(qs.len + 1, GFP_NOFS);
+		if (unlikely(!name))
+			goto out;
+	}
+
+	/* doubly whiteout-ed */
+	memcpy(name, AUFS_WH_PFX AUFS_WH_PFX, AUFS_WH_PFX_LEN * 2);
+	p = name + AUFS_WH_PFX_LEN * 2;
+	memcpy(p, prefix->name, prefix->len);
+	p += prefix->len;
+	*p++ = '.';
+	AuDebugOn(name + qs.len + 1 - p <= HEX_LEN);
+
+	qs.name = name;
+	for (i = 0; i < 3; i++) {
+		sprintf(p, "%.*d", HEX_LEN, cnt++);
+		dentry = au_sio_lkup_one(&qs, h_parent, br);
+		if (IS_ERR(dentry) || !dentry->d_inode)
+			goto out_name;
+		dput(dentry);
+	}
+	/* AuWarn("could not get random name\n"); */
+	dentry = ERR_PTR(-EEXIST);
+	AuDbg("%.*s\n", AuLNPair(&qs));
+	BUG();
+
+ out_name:
+	if (name != defname)
+		kfree(name);
+ out:
+	return dentry;
+#undef HEX_LEN
+}
+
+/*
+ * rename the @h_dentry on @br to the whiteouted temporary name.
+ */
+int au_whtmp_ren(struct dentry *h_dentry, struct au_branch *br)
+{
+	int err;
+	struct path h_path = {
+		.mnt = br->br_mnt
+	};
+	struct inode *h_dir;
+	struct dentry *h_parent;
+
+	h_parent = h_dentry->d_parent; /* dir inode is locked */
+	h_dir = h_parent->d_inode;
+	IMustLock(h_dir);
+
+	h_path.dentry = au_whtmp_lkup(h_parent, br, &h_dentry->d_name);
+	err = PTR_ERR(h_path.dentry);
+	if (IS_ERR(h_path.dentry))
+		goto out;
+
+	/* under the same dir, no need to lock_rename() */
+	err = vfsub_rename(h_dir, h_dentry, h_dir, &h_path);
+	AuTraceErr(err);
+	dput(h_path.dentry);
+
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+/*
+ * functions for removing a whiteout
+ */
+
+static int do_unlink_wh(struct inode *h_dir, struct path *h_path)
+{
+	int force;
+
+	/*
+	 * forces superio when the dir has a sticky bit.
+	 * this may be a violation of unix fs semantics.
+	 */
+	force = (h_dir->i_mode & S_ISVTX)
+		&& h_path->dentry->d_inode->i_uid != current_fsuid();
+	return vfsub_unlink(h_dir, h_path, force);
+}
+
+int au_wh_unlink_dentry(struct inode *h_dir, struct path *h_path,
+			struct dentry *dentry)
+{
+	int err;
+
+	err = do_unlink_wh(h_dir, h_path);
+	if (!err && dentry)
+		au_set_dbwh(dentry, -1);
+
+	return err;
+}
+
+static int unlink_wh_name(struct dentry *h_parent, struct qstr *wh,
+			  struct au_branch *br)
+{
+	int err;
+	struct path h_path = {
+		.mnt = br->br_mnt
+	};
+
+	err = 0;
+	h_path.dentry = au_lkup_one(wh, h_parent, br, /*nd*/NULL);
+	if (IS_ERR(h_path.dentry))
+		err = PTR_ERR(h_path.dentry);
+	else {
+		if (h_path.dentry->d_inode
+		    && S_ISREG(h_path.dentry->d_inode->i_mode))
+			err = do_unlink_wh(h_parent->d_inode, &h_path);
+		dput(h_path.dentry);
+	}
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+/*
+ * initialize/clean whiteout for a branch
+ */
+
+static void au_wh_clean(struct inode *h_dir, struct path *whpath,
+			const int isdir)
+{
+	int err;
+
+	if (!whpath->dentry->d_inode)
+		return;
+
+	err = mnt_want_write(whpath->mnt);
+	if (!err) {
+		if (isdir)
+			err = vfsub_rmdir(h_dir, whpath);
+		else
+			err = vfsub_unlink(h_dir, whpath, /*force*/0);
+		mnt_drop_write(whpath->mnt);
+	}
+	if (unlikely(err))
+		AuWarn("failed removing %.*s (%d), ignored.\n",
+		       AuDLNPair(whpath->dentry), err);
+}
+
+static int test_linkable(struct dentry *h_root)
+{
+	struct inode *h_dir = h_root->d_inode;
+
+	if (h_dir->i_op->link)
+		return 0;
+
+	AuErr("%.*s (%s) doesn't support link(2), use noplink and rw+nolwh\n",
+	      AuDLNPair(h_root), au_sbtype(h_root->d_sb));
+	return -ENOSYS;
+}
+
+/* todo: should this mkdir be done in /sbin/mount.aufs helper? */
+static int au_whdir(struct inode *h_dir, struct path *path)
+{
+	int err;
+
+	err = -EEXIST;
+	if (!path->dentry->d_inode) {
+		int mode = S_IRWXU;
+
+		if (au_test_nfs(path->dentry->d_sb))
+			mode |= S_IXUGO;
+		err = mnt_want_write(path->mnt);
+		if (!err) {
+			err = vfsub_mkdir(h_dir, path, mode);
+			mnt_drop_write(path->mnt);
+		}
+	} else if (S_ISDIR(path->dentry->d_inode->i_mode))
+		err = 0;
+	else
+		AuErr("unknown %.*s exists\n", AuDLNPair(path->dentry));
+
+	return err;
+}
+
+struct au_wh_base {
+	const struct qstr *name;
+	struct dentry *dentry;
+};
+
+static void au_wh_init_ro(struct inode *h_dir, struct au_wh_base base[],
+			  struct path *h_path)
+{
+	h_path->dentry = base[AuBrWh_BASE].dentry;
+	au_wh_clean(h_dir, h_path, /*isdir*/0);
+	h_path->dentry = base[AuBrWh_PLINK].dentry;
+	au_wh_clean(h_dir, h_path, /*isdir*/1);
+	h_path->dentry = base[AuBrWh_ORPH].dentry;
+	au_wh_clean(h_dir, h_path, /*isdir*/1);
+}
+
+/*
+ * returns tri-state,
+ * minus: error, caller should print the mesage
+ * zero: succuess
+ * plus: error, caller should NOT print the mesage
+ */
+static int au_wh_init_rw_nolink(struct dentry *h_root, struct au_wbr *wbr,
+				int do_plink, struct au_wh_base base[],
+				struct path *h_path)
+{
+	int err;
+	struct inode *h_dir;
+
+	h_dir = h_root->d_inode;
+	h_path->dentry = base[AuBrWh_BASE].dentry;
+	au_wh_clean(h_dir, h_path, /*isdir*/0);
+	h_path->dentry = base[AuBrWh_PLINK].dentry;
+	if (do_plink) {
+		err = test_linkable(h_root);
+		if (unlikely(err)) {
+			err = 1;
+			goto out;
+		}
+
+		err = au_whdir(h_dir, h_path);
+		if (unlikely(err))
+			goto out;
+		wbr->wbr_plink = dget(base[AuBrWh_PLINK].dentry);
+	} else
+		au_wh_clean(h_dir, h_path, /*isdir*/1);
+	h_path->dentry = base[AuBrWh_ORPH].dentry;
+	err = au_whdir(h_dir, h_path);
+	if (unlikely(err))
+		goto out;
+	wbr->wbr_orph = dget(base[AuBrWh_ORPH].dentry);
+
+ out:
+	return err;
+}
+
+/*
+ * for the moment, aufs supports the branch filesystem which does not support
+ * link(2). testing on FAT which does not support i_op->setattr() fully either,
+ * copyup failed. finally, such filesystem will not be used as the writable
+ * branch.
+ *
+ * returns tri-state, see above.
+ */
+static int au_wh_init_rw(struct dentry *h_root, struct au_wbr *wbr,
+			 int do_plink, struct au_wh_base base[],
+			 struct path *h_path)
+{
+	int err;
+	struct inode *h_dir;
+
+	WbrWhMustWriteLock(wbr);
+
+	err = test_linkable(h_root);
+	if (unlikely(err)) {
+		err = 1;
+		goto out;
+	}
+
+	/*
+	 * todo: should this create be done in /sbin/mount.aufs helper?
+	 */
+	err = -EEXIST;
+	h_dir = h_root->d_inode;
+	if (!base[AuBrWh_BASE].dentry->d_inode) {
+		err = mnt_want_write(h_path->mnt);
+		if (!err) {
+			h_path->dentry = base[AuBrWh_BASE].dentry;
+			err = vfsub_create(h_dir, h_path, WH_MASK);
+			mnt_drop_write(h_path->mnt);
+		}
+	} else if (S_ISREG(base[AuBrWh_BASE].dentry->d_inode->i_mode))
+		err = 0;
+	else
+		AuErr("unknown %.*s/%.*s exists\n",
+		      AuDLNPair(h_root), AuDLNPair(base[AuBrWh_BASE].dentry));
+	if (unlikely(err))
+		goto out;
+
+	h_path->dentry = base[AuBrWh_PLINK].dentry;
+	if (do_plink) {
+		err = au_whdir(h_dir, h_path);
+		if (unlikely(err))
+			goto out;
+		wbr->wbr_plink = dget(base[AuBrWh_PLINK].dentry);
+	} else
+		au_wh_clean(h_dir, h_path, /*isdir*/1);
+	wbr->wbr_whbase = dget(base[AuBrWh_BASE].dentry);
+
+	h_path->dentry = base[AuBrWh_ORPH].dentry;
+	err = au_whdir(h_dir, h_path);
+	if (unlikely(err))
+		goto out;
+	wbr->wbr_orph = dget(base[AuBrWh_ORPH].dentry);
+
+ out:
+	return err;
+}
+
+/*
+ * initialize the whiteout base file/dir for @br.
+ */
+int au_wh_init(struct dentry *h_root, struct au_branch *br,
+	       struct super_block *sb)
+{
+	int err, i;
+	const unsigned char do_plink
+		= !!au_opt_test(au_mntflags(sb), PLINK);
+	struct path path = {
+		.mnt = br->br_mnt
+	};
+	struct inode *h_dir;
+	struct au_wbr *wbr = br->br_wbr;
+	static const struct qstr base_name[] = {
+		[AuBrWh_BASE] = {
+			.name	= AUFS_BASE_NAME,
+			.len	= sizeof(AUFS_BASE_NAME) - 1
+		},
+		[AuBrWh_PLINK] = {
+			.name	= AUFS_PLINKDIR_NAME,
+			.len	= sizeof(AUFS_PLINKDIR_NAME) - 1
+		},
+		[AuBrWh_ORPH] = {
+			.name	= AUFS_ORPHDIR_NAME,
+			.len	= sizeof(AUFS_ORPHDIR_NAME) - 1
+		}
+	};
+	struct au_wh_base base[] = {
+		[AuBrWh_BASE] = {
+			.name	= base_name + AuBrWh_BASE,
+			.dentry	= NULL
+		},
+		[AuBrWh_PLINK] = {
+			.name	= base_name + AuBrWh_PLINK,
+			.dentry	= NULL
+		},
+		[AuBrWh_ORPH] = {
+			.name	= base_name + AuBrWh_ORPH,
+			.dentry	= NULL
+		}
+	};
+
+	if (wbr)
+		WbrWhMustWriteLock(wbr);
+
+	h_dir = h_root->d_inode;
+	for (i = 0; i < AuBrWh_Last; i++) {
+		/* doubly whiteouted */
+		struct dentry *d;
+
+		d = au_wh_lkup(h_root, (void *)base[i].name, br);
+		err = PTR_ERR(d);
+		if (IS_ERR(d))
+			goto out;
+
+		base[i].dentry = d;
+		AuDebugOn(wbr
+			  && wbr->wbr_wh[i]
+			  && wbr->wbr_wh[i] != base[i].dentry);
+	}
+
+	if (wbr)
+		for (i = 0; i < AuBrWh_Last; i++) {
+			dput(wbr->wbr_wh[i]);
+			wbr->wbr_wh[i] = NULL;
+		}
+
+	err = 0;
+
+	switch (br->br_perm) {
+	case AuBrPerm_RO:
+	case AuBrPerm_ROWH:
+	case AuBrPerm_RR:
+	case AuBrPerm_RRWH:
+		au_wh_init_ro(h_dir, base, &path);
+		break;
+
+	case AuBrPerm_RWNoLinkWH:
+		err = au_wh_init_rw_nolink(h_root, wbr, do_plink, base, &path);
+		if (err > 0)
+			goto out;
+		else if (err)
+			goto out_err;
+		break;
+
+	case AuBrPerm_RW:
+		err = au_wh_init_rw(h_root, wbr, do_plink, base, &path);
+		if (err > 0)
+			goto out;
+		else if (err)
+			goto out_err;
+		break;
+
+	default:
+		BUG();
+	}
+	goto out; /* success */
+
+ out_err:
+	AuErr("an error(%d) on the writable branch %.*s(%s)\n",
+	      err, AuDLNPair(h_root), au_sbtype(h_root->d_sb));
+ out:
+	for (i = 0; i < AuBrWh_Last; i++)
+		dput(base[i].dentry);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+/*
+ * whiteouts are all hard-linked usually.
+ * when its link count reaches a ceiling, we create a new whiteout base
+ * asynchronously.
+ */
+
+struct reinit_br_wh {
+	struct super_block *sb;
+	struct au_branch *br;
+};
+
+static void reinit_br_wh(void *arg)
+{
+	int err;
+	aufs_bindex_t bindex;
+	struct path h_path;
+	struct reinit_br_wh *a = arg;
+	struct au_wbr *wbr;
+	struct inode *dir;
+	struct dentry *h_root;
+	struct au_hinode *hdir;
+
+	err = 0;
+	wbr = a->br->br_wbr;
+	/* big aufs lock */
+	si_noflush_write_lock(a->sb);
+	if (!au_br_writable(a->br->br_perm))
+		goto out;
+	bindex = au_br_index(a->sb, a->br->br_id);
+	if (unlikely(bindex < 0))
+		goto out;
+
+	di_read_lock_parent(a->sb->s_root, AuLock_IR);
+	dir = a->sb->s_root->d_inode;
+	hdir = au_hi(dir, bindex);
+	h_root = au_h_dptr(a->sb->s_root, bindex);
+
+	au_hin_imtx_lock_nested(hdir, AuLsc_I_PARENT);
+	wbr_wh_write_lock(wbr);
+	err = au_h_verify(wbr->wbr_whbase, au_opt_udba(a->sb), hdir->hi_inode,
+			  h_root, a->br);
+	if (!err) {
+		err = mnt_want_write(a->br->br_mnt);
+		if (!err) {
+			h_path.dentry = wbr->wbr_whbase;
+			h_path.mnt = a->br->br_mnt;
+			err = vfsub_unlink(hdir->hi_inode, &h_path, /*force*/0);
+			mnt_drop_write(a->br->br_mnt);
+		}
+	} else {
+		AuWarn("%.*s is moved, ignored\n", AuDLNPair(wbr->wbr_whbase));
+		err = 0;
+	}
+	dput(wbr->wbr_whbase);
+	wbr->wbr_whbase = NULL;
+	if (!err)
+		err = au_wh_init(h_root, a->br, a->sb);
+	wbr_wh_write_unlock(wbr);
+	au_hin_imtx_unlock(hdir);
+	di_read_unlock(a->sb->s_root, AuLock_IR);
+
+ out:
+	if (wbr)
+		atomic_dec(&wbr->wbr_wh_running);
+	atomic_dec(&a->br->br_count);
+	au_nwt_done(&au_sbi(a->sb)->si_nowait);
+	si_write_unlock(a->sb);
+	kfree(arg);
+	if (unlikely(err))
+		AuIOErr("err %d\n", err);
+}
+
+static void kick_reinit_br_wh(struct super_block *sb, struct au_branch *br)
+{
+	int do_dec, wkq_err;
+	struct reinit_br_wh *arg;
+
+	do_dec = 1;
+	if (atomic_inc_return(&br->br_wbr->wbr_wh_running) != 1)
+		goto out;
+
+	/* ignore ENOMEM */
+	arg = kmalloc(sizeof(*arg), GFP_NOFS);
+	if (arg) {
+		/*
+		 * dec(wh_running), kfree(arg) and dec(br_count)
+		 * in reinit function
+		 */
+		arg->sb = sb;
+		arg->br = br;
+		atomic_inc(&br->br_count);
+		wkq_err = au_wkq_nowait(reinit_br_wh, arg, sb);
+		if (unlikely(wkq_err)) {
+			atomic_dec(&br->br_wbr->wbr_wh_running);
+			atomic_dec(&br->br_count);
+			kfree(arg);
+		}
+		do_dec = 0;
+	}
+
+ out:
+	if (do_dec)
+		atomic_dec(&br->br_wbr->wbr_wh_running);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * create the whiteout @wh.
+ */
+static int link_or_create_wh(struct super_block *sb, aufs_bindex_t bindex,
+			     struct dentry *wh)
+{
+	int err;
+	struct path h_path = {
+		.dentry = wh
+	};
+	struct au_branch *br;
+	struct au_wbr *wbr;
+	struct dentry *h_parent;
+	struct inode *h_dir;
+
+	h_parent = wh->d_parent; /* dir inode is locked */
+	h_dir = h_parent->d_inode;
+	IMustLock(h_dir);
+
+	br = au_sbr(sb, bindex);
+	h_path.mnt = br->br_mnt;
+	wbr = br->br_wbr;
+	wbr_wh_read_lock(wbr);
+	if (wbr->wbr_whbase) {
+		err = vfsub_link(wbr->wbr_whbase, h_dir, &h_path);
+		if (!err || err != -EMLINK)
+			goto out;
+
+		/* link count full. re-initialize br_whbase. */
+		kick_reinit_br_wh(sb, br);
+	}
+
+	/* return this error in this context */
+	err = vfsub_create(h_dir, &h_path, WH_MASK);
+
+ out:
+	wbr_wh_read_unlock(wbr);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * create or remove the diropq.
+ */
+static struct dentry *do_diropq(struct dentry *dentry, aufs_bindex_t bindex,
+				unsigned int flags)
+{
+	struct dentry *opq_dentry, *h_dentry;
+	struct super_block *sb;
+	struct au_branch *br;
+	int err;
+
+	sb = dentry->d_sb;
+	br = au_sbr(sb, bindex);
+	h_dentry = au_h_dptr(dentry, bindex);
+	opq_dentry = au_lkup_one(&diropq_name, h_dentry, br, /*nd*/NULL);
+	if (IS_ERR(opq_dentry))
+		goto out;
+
+	if (au_ftest_diropq(flags, CREATE)) {
+		err = link_or_create_wh(sb, bindex, opq_dentry);
+		if (!err) {
+			au_set_dbdiropq(dentry, bindex);
+			goto out; /* success */
+		}
+	} else {
+		struct path tmp = {
+			.dentry = opq_dentry,
+			.mnt	= br->br_mnt
+		};
+		err = do_unlink_wh(au_h_iptr(dentry->d_inode, bindex), &tmp);
+		if (!err)
+			au_set_dbdiropq(dentry, -1);
+	}
+	dput(opq_dentry);
+	opq_dentry = ERR_PTR(err);
+
+ out:
+	return opq_dentry;
+}
+
+struct do_diropq_args {
+	struct dentry **errp;
+	struct dentry *dentry;
+	aufs_bindex_t bindex;
+	unsigned int flags;
+};
+
+static void call_do_diropq(void *args)
+{
+	struct do_diropq_args *a = args;
+	*a->errp = do_diropq(a->dentry, a->bindex, a->flags);
+}
+
+struct dentry *au_diropq_sio(struct dentry *dentry, aufs_bindex_t bindex,
+			     unsigned int flags)
+{
+	struct dentry *diropq, *h_dentry;
+
+	h_dentry = au_h_dptr(dentry, bindex);
+	if (!au_test_h_perm_sio(h_dentry->d_inode, MAY_EXEC | MAY_WRITE))
+		diropq = do_diropq(dentry, bindex, flags);
+	else {
+		int wkq_err;
+		struct do_diropq_args args = {
+			.errp		= &diropq,
+			.dentry		= dentry,
+			.bindex		= bindex,
+			.flags		= flags
+		};
+
+		wkq_err = au_wkq_wait(call_do_diropq, &args);
+		if (unlikely(wkq_err))
+			diropq = ERR_PTR(wkq_err);
+	}
+
+	return diropq;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * lookup whiteout dentry.
+ * @h_parent: lower parent dentry which must exist and be locked
+ * @base_name: name of dentry which will be whiteouted
+ * returns dentry for whiteout.
+ */
+struct dentry *au_wh_lkup(struct dentry *h_parent, struct qstr *base_name,
+			  struct au_branch *br)
+{
+	int err;
+	struct qstr wh_name;
+	struct dentry *wh_dentry;
+
+	err = au_wh_name_alloc(&wh_name, base_name);
+	wh_dentry = ERR_PTR(err);
+	if (!err) {
+		wh_dentry = au_lkup_one(&wh_name, h_parent, br, /*nd*/NULL);
+		kfree(wh_name.name);
+	}
+	return wh_dentry;
+}
+
+/*
+ * link/create a whiteout for @dentry on @bindex.
+ */
+struct dentry *au_wh_create(struct dentry *dentry, aufs_bindex_t bindex,
+			    struct dentry *h_parent)
+{
+	struct dentry *wh_dentry;
+	struct super_block *sb;
+	int err;
+
+	sb = dentry->d_sb;
+	wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, au_sbr(sb, bindex));
+	if (!IS_ERR(wh_dentry) && !wh_dentry->d_inode) {
+		err = link_or_create_wh(sb, bindex, wh_dentry);
+		if (!err)
+			au_set_dbwh(dentry, bindex);
+		else {
+			dput(wh_dentry);
+			wh_dentry = ERR_PTR(err);
+		}
+	}
+
+	return wh_dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* Delete all whiteouts in this directory on branch bindex. */
+static int del_wh_children(struct dentry *h_dentry, struct au_nhash *whlist,
+			   aufs_bindex_t bindex, struct au_branch *br)
+{
+	int err;
+	unsigned long ul, n;
+	struct qstr wh_name;
+	char *p;
+	struct hlist_head *head;
+	struct au_vdir_wh *tpos;
+	struct hlist_node *pos;
+	struct au_vdir_destr *str;
+
+	err = -ENOMEM;
+	p = __getname();
+	wh_name.name = p;
+	if (unlikely(!wh_name.name))
+		goto out;
+
+	err = 0;
+	memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
+	p += AUFS_WH_PFX_LEN;
+	n = whlist->nh_num;
+	head = whlist->nh_head;
+	for (ul = 0; !err && ul < n; ul++, head++) {
+		hlist_for_each_entry(tpos, pos, head, wh_hash) {
+			if (tpos->wh_bindex != bindex)
+				continue;
+
+			str = &tpos->wh_str;
+			if (str->len + AUFS_WH_PFX_LEN <= PATH_MAX) {
+				memcpy(p, str->name, str->len);
+				wh_name.len = AUFS_WH_PFX_LEN + str->len;
+				err = unlink_wh_name(h_dentry, &wh_name, br);
+				if (!err)
+					continue;
+				break;
+			}
+			AuIOErr("whiteout name too long %.*s\n",
+				str->len, str->name);
+			err = -EIO;
+			break;
+		}
+	}
+	__putname(wh_name.name);
+
+ out:
+	return err;
+}
+
+struct del_wh_children_args {
+	int *errp;
+	struct dentry *h_dentry;
+	struct au_nhash whlist;
+	aufs_bindex_t bindex;
+	struct au_branch *br;
+};
+
+static void call_del_wh_children(void *args)
+{
+	struct del_wh_children_args *a = args;
+	*a->errp = del_wh_children(a->h_dentry, &a->whlist, a->bindex, a->br);
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_whtmp_rmdir *au_whtmp_rmdir_alloc(struct super_block *sb, gfp_t gfp)
+{
+	struct au_whtmp_rmdir *whtmp;
+	int err;
+
+	SiMustAnyLock(sb);
+
+	whtmp = kmalloc(sizeof(*whtmp), gfp);
+	if (unlikely(!whtmp)) {
+		whtmp = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	whtmp->dir = NULL;
+	whtmp->wh_dentry = NULL;
+	err = au_nhash_alloc(&whtmp->whlist, au_sbi(sb)->si_rdhash, gfp);
+	if (!err)
+		return whtmp; /* success */
+
+	kfree(whtmp);
+	whtmp = ERR_PTR(err);
+
+ out:
+	return whtmp;
+}
+
+void au_whtmp_rmdir_free(struct au_whtmp_rmdir *whtmp)
+{
+	dput(whtmp->wh_dentry);
+	iput(whtmp->dir);
+	au_nhash_wh_free(&whtmp->whlist);
+	kfree(whtmp);
+}
+
+/*
+ * rmdir the whiteouted temporary named dir @h_dentry.
+ * @whlist: whiteouted children.
+ */
+int au_whtmp_rmdir(struct inode *dir, aufs_bindex_t bindex,
+		   struct dentry *wh_dentry, struct au_nhash *whlist)
+{
+	int err;
+	struct path h_tmp;
+	struct inode *wh_inode, *h_dir;
+	struct au_branch *br;
+
+	h_dir = wh_dentry->d_parent->d_inode; /* dir inode is locked */
+	IMustLock(h_dir);
+
+	br = au_sbr(dir->i_sb, bindex);
+	wh_inode = wh_dentry->d_inode;
+	mutex_lock_nested(&wh_inode->i_mutex, AuLsc_I_CHILD);
+
+	/*
+	 * someone else might change some whiteouts while we were sleeping.
+	 * it means this whlist may have an obsoleted entry.
+	 */
+	if (!au_test_h_perm_sio(wh_inode, MAY_EXEC | MAY_WRITE))
+		err = del_wh_children(wh_dentry, whlist, bindex, br);
+	else {
+		int wkq_err;
+		struct del_wh_children_args args = {
+			.errp		= &err,
+			.h_dentry	= wh_dentry,
+			.whlist		= *whlist,
+			.bindex		= bindex,
+			.br		= br
+		};
+
+		wkq_err = au_wkq_wait(call_del_wh_children, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	}
+	mutex_unlock(&wh_inode->i_mutex);
+
+	if (!err) {
+		h_tmp.dentry = wh_dentry;
+		h_tmp.mnt = br->br_mnt;
+		err = vfsub_rmdir(h_dir, &h_tmp);
+		/* d_drop(h_dentry); */
+	}
+
+	if (!err) {
+		if (au_ibstart(dir) == bindex) {
+			au_cpup_attr_timesizes(dir);
+			drop_nlink(dir);
+		}
+		return 0; /* success */
+	}
+
+	AuWarn("failed removing %.*s(%d), ignored\n",
+	       AuDLNPair(wh_dentry), err);
+	return err;
+}
+
+static void call_rmdir_whtmp(void *args)
+{
+	int err;
+	struct au_whtmp_rmdir *a = args;
+	struct super_block *sb;
+	struct dentry *h_parent;
+	struct inode *h_dir;
+	struct au_branch *br;
+	struct au_hinode *hdir;
+
+	/* rmdir by nfsd may cause deadlock with this i_mutex */
+	/* mutex_lock(&a->dir->i_mutex); */
+	sb = a->dir->i_sb;
+	si_noflush_read_lock(sb);
+	err = au_test_ro(sb, a->bindex, NULL);
+	if (unlikely(err))
+		goto out;
+
+	err = -EIO;
+	br = au_sbr(sb, a->bindex);
+	ii_write_lock_parent(a->dir);
+	h_parent = dget_parent(a->wh_dentry);
+	h_dir = h_parent->d_inode;
+	hdir = au_hi(a->dir, a->bindex);
+	au_hin_imtx_lock_nested(hdir, AuLsc_I_PARENT);
+	err = au_h_verify(a->wh_dentry, au_opt_udba(sb), h_dir, h_parent, br);
+	if (!err) {
+		err = mnt_want_write(br->br_mnt);
+		if (!err) {
+			err = au_whtmp_rmdir(a->dir, a->bindex, a->wh_dentry,
+					     &a->whlist);
+			mnt_drop_write(br->br_mnt);
+		}
+	}
+	au_hin_imtx_unlock(hdir);
+	dput(h_parent);
+	ii_write_unlock(a->dir);
+
+ out:
+	/* mutex_unlock(&a->dir->i_mutex); */
+	au_nwt_done(&au_sbi(sb)->si_nowait);
+	si_read_unlock(sb);
+	au_whtmp_rmdir_free(a);
+	if (unlikely(err))
+		AuIOErr("err %d\n", err);
+}
+
+void au_whtmp_kick_rmdir(struct inode *dir, aufs_bindex_t bindex,
+			 struct dentry *wh_dentry, struct au_whtmp_rmdir *args)
+{
+	int wkq_err;
+
+	IMustLock(dir);
+
+	/* all post-process will be done in do_rmdir_whtmp(). */
+	args->dir = au_igrab(dir);
+	args->bindex = bindex;
+	args->wh_dentry = dget(wh_dentry);
+	wkq_err = au_wkq_nowait(call_rmdir_whtmp, args, dir->i_sb);
+	if (unlikely(wkq_err)) {
+		AuWarn("rmdir error %.*s (%d), ignored\n",
+		       AuDLNPair(wh_dentry), wkq_err);
+		au_whtmp_rmdir_free(args);
+	}
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/whout.h linux-2.6.31.4/fs/aufs/whout.h
--- linux-2.6.31.4.orig/fs/aufs/whout.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/whout.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * whiteout for logical deletion and opaque directory
+ */
+
+#ifndef __AUFS_WHOUT_H__
+#define __AUFS_WHOUT_H__
+
+#ifdef __KERNEL__
+
+#include <linux/aufs_type.h>
+#include "dir.h"
+
+/* whout.c */
+int au_wh_name_alloc(struct qstr *wh, const struct qstr *name);
+struct au_branch;
+int au_wh_test(struct dentry *h_parent, struct qstr *wh_name,
+	       struct au_branch *br, int try_sio);
+int au_diropq_test(struct dentry *h_dentry, struct au_branch *br);
+struct dentry *au_whtmp_lkup(struct dentry *h_parent, struct au_branch *br,
+			     struct qstr *prefix);
+int au_whtmp_ren(struct dentry *h_dentry, struct au_branch *br);
+int au_wh_unlink_dentry(struct inode *h_dir, struct path *h_path,
+			struct dentry *dentry);
+int au_wh_init(struct dentry *h_parent, struct au_branch *br,
+	       struct super_block *sb);
+
+/* diropq flags */
+#define AuDiropq_CREATE	1
+#define au_ftest_diropq(flags, name)	((flags) & AuDiropq_##name)
+#define au_fset_diropq(flags, name)	{ (flags) |= AuDiropq_##name; }
+#define au_fclr_diropq(flags, name)	{ (flags) &= ~AuDiropq_##name; }
+
+struct dentry *au_diropq_sio(struct dentry *dentry, aufs_bindex_t bindex,
+			     unsigned int flags);
+struct dentry *au_wh_lkup(struct dentry *h_parent, struct qstr *base_name,
+			  struct au_branch *br);
+struct dentry *au_wh_create(struct dentry *dentry, aufs_bindex_t bindex,
+			    struct dentry *h_parent);
+
+/* real rmdir for the whiteout-ed dir */
+struct au_whtmp_rmdir {
+	struct inode *dir;
+	aufs_bindex_t bindex;
+	struct dentry *wh_dentry;
+	struct au_nhash whlist;
+};
+
+struct au_whtmp_rmdir *au_whtmp_rmdir_alloc(struct super_block *sb, gfp_t gfp);
+void au_whtmp_rmdir_free(struct au_whtmp_rmdir *whtmp);
+int au_whtmp_rmdir(struct inode *dir, aufs_bindex_t bindex,
+		   struct dentry *wh_dentry, struct au_nhash *whlist);
+void au_whtmp_kick_rmdir(struct inode *dir, aufs_bindex_t bindex,
+			 struct dentry *wh_dentry, struct au_whtmp_rmdir *args);
+
+/* ---------------------------------------------------------------------- */
+
+static inline struct dentry *au_diropq_create(struct dentry *dentry,
+					      aufs_bindex_t bindex)
+{
+	return au_diropq_sio(dentry, bindex, AuDiropq_CREATE);
+}
+
+static inline int au_diropq_remove(struct dentry *dentry, aufs_bindex_t bindex)
+{
+	return PTR_ERR(au_diropq_sio(dentry, bindex, !AuDiropq_CREATE));
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_WHOUT_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/wkq.c linux-2.6.31.4/fs/aufs/wkq.c
--- linux-2.6.31.4.orig/fs/aufs/wkq.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/wkq.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,259 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * workqueue for asynchronous/super-io operations
+ * todo: try new dredential scheme
+ */
+
+#include <linux/module.h>
+#include "aufs.h"
+
+/* internal workqueue named AUFS_WKQ_NAME */
+static struct au_wkq {
+	struct workqueue_struct	*q;
+
+	/* balancing */
+	atomic_t		busy;
+} *au_wkq;
+
+struct au_wkinfo {
+	struct work_struct wk;
+	struct super_block *sb;
+
+	unsigned int flags; /* see wkq.h */
+
+	au_wkq_func_t func;
+	void *args;
+
+	atomic_t *busyp;
+	struct completion *comp;
+};
+
+/* ---------------------------------------------------------------------- */
+
+static int enqueue(struct au_wkq *wkq, struct au_wkinfo *wkinfo)
+{
+	wkinfo->busyp = &wkq->busy;
+	if (au_ftest_wkq(wkinfo->flags, WAIT))
+		return !queue_work(wkq->q, &wkinfo->wk);
+	else
+		return !schedule_work(&wkinfo->wk);
+}
+
+static void do_wkq(struct au_wkinfo *wkinfo)
+{
+	unsigned int idle, n;
+	int i, idle_idx;
+
+	while (1) {
+		if (au_ftest_wkq(wkinfo->flags, WAIT)) {
+			idle_idx = 0;
+			idle = UINT_MAX;
+			for (i = 0; i < aufs_nwkq; i++) {
+				n = atomic_inc_return(&au_wkq[i].busy);
+				if (n == 1 && !enqueue(au_wkq + i, wkinfo))
+					return; /* success */
+
+				if (n < idle) {
+					idle_idx = i;
+					idle = n;
+				}
+				atomic_dec(&au_wkq[i].busy);
+			}
+		} else
+			idle_idx = aufs_nwkq;
+
+		atomic_inc(&au_wkq[idle_idx].busy);
+		if (!enqueue(au_wkq + idle_idx, wkinfo))
+			return; /* success */
+
+		/* impossible? */
+		AuWarn1("failed to queue_work()\n");
+		yield();
+	}
+}
+
+static void wkq_func(struct work_struct *wk)
+{
+	struct au_wkinfo *wkinfo = container_of(wk, struct au_wkinfo, wk);
+
+	wkinfo->func(wkinfo->args);
+	atomic_dec_return(wkinfo->busyp);
+	if (au_ftest_wkq(wkinfo->flags, WAIT))
+		complete(wkinfo->comp);
+	else {
+		kobject_put(&au_sbi(wkinfo->sb)->si_kobj);
+		module_put(THIS_MODULE);
+		kfree(wkinfo);
+	}
+}
+
+/*
+ * Since struct completion is large, try allocating it dynamically.
+ */
+#if defined(CONFIG_4KSTACKS) || defined(AuTest4KSTACKS)
+#define AuWkqCompDeclare(name)	struct completion *comp = NULL
+
+static int au_wkq_comp_alloc(struct au_wkinfo *wkinfo, struct completion **comp)
+{
+	*comp = kmalloc(sizeof(**comp), GFP_NOFS);
+	if (*comp) {
+		init_completion(*comp);
+		wkinfo->comp = *comp;
+		return 0;
+	}
+	return -ENOMEM;
+}
+
+static void au_wkq_comp_free(struct completion *comp)
+{
+	kfree(comp);
+}
+
+#else
+
+/* no braces */
+#define AuWkqCompDeclare(name) \
+	DECLARE_COMPLETION_ONSTACK(_ ## name); \
+	struct completion *comp = &_ ## name
+
+static int au_wkq_comp_alloc(struct au_wkinfo *wkinfo, struct completion **comp)
+{
+	wkinfo->comp = *comp;
+	return 0;
+}
+
+static void au_wkq_comp_free(struct completion *comp __maybe_unused)
+{
+	/* empty */
+}
+#endif /* 4KSTACKS */
+
+static void au_wkq_run(struct au_wkinfo *wkinfo)
+{
+	au_dbg_verify_kthread();
+	INIT_WORK(&wkinfo->wk, wkq_func);
+	do_wkq(wkinfo);
+}
+
+int au_wkq_wait(au_wkq_func_t func, void *args)
+{
+	int err;
+	AuWkqCompDeclare(comp);
+	struct au_wkinfo wkinfo = {
+		.flags	= AuWkq_WAIT,
+		.func	= func,
+		.args	= args
+	};
+
+	err = au_wkq_comp_alloc(&wkinfo, &comp);
+	if (!err) {
+		au_wkq_run(&wkinfo);
+		/* no timeout, no interrupt */
+		wait_for_completion(wkinfo.comp);
+		au_wkq_comp_free(comp);
+	}
+
+	return err;
+
+}
+
+int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb)
+{
+	int err;
+	struct au_wkinfo *wkinfo;
+
+	atomic_inc(&au_sbi(sb)->si_nowait.nw_len);
+
+	/*
+	 * wkq_func() must free this wkinfo.
+	 * it highly depends upon the implementation of workqueue.
+	 */
+	err = 0;
+	wkinfo = kmalloc(sizeof(*wkinfo), GFP_NOFS);
+	if (wkinfo) {
+		wkinfo->sb = sb;
+		wkinfo->flags = !AuWkq_WAIT;
+		wkinfo->func = func;
+		wkinfo->args = args;
+		wkinfo->comp = NULL;
+		kobject_get(&au_sbi(sb)->si_kobj);
+		__module_get(THIS_MODULE);
+
+		au_wkq_run(wkinfo);
+	} else {
+		err = -ENOMEM;
+		atomic_dec(&au_sbi(sb)->si_nowait.nw_len);
+	}
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_nwt_init(struct au_nowait_tasks *nwt)
+{
+	atomic_set(&nwt->nw_len, 0);
+	/* smp_mb();*/ /* atomic_set */
+	init_waitqueue_head(&nwt->nw_wq);
+}
+
+void au_wkq_fin(void)
+{
+	int i;
+
+	for (i = 0; i < aufs_nwkq; i++)
+		if (au_wkq[i].q && !IS_ERR(au_wkq[i].q))
+			destroy_workqueue(au_wkq[i].q);
+	kfree(au_wkq);
+}
+
+int __init au_wkq_init(void)
+{
+	int err, i;
+	struct au_wkq *nowaitq;
+
+	/* '+1' is for accounting of nowait queue */
+	err = -ENOMEM;
+	au_wkq = kcalloc(aufs_nwkq + 1, sizeof(*au_wkq), GFP_NOFS);
+	if (unlikely(!au_wkq))
+		goto out;
+
+	err = 0;
+	for (i = 0; i < aufs_nwkq; i++) {
+		au_wkq[i].q = create_singlethread_workqueue(AUFS_WKQ_NAME);
+		if (au_wkq[i].q && !IS_ERR(au_wkq[i].q)) {
+			atomic_set(&au_wkq[i].busy, 0);
+			continue;
+		}
+
+		err = PTR_ERR(au_wkq[i].q);
+		au_wkq_fin();
+		goto out;
+	}
+
+	/* nowait accounting */
+	nowaitq = au_wkq + aufs_nwkq;
+	atomic_set(&nowaitq->busy, 0);
+	nowaitq->q = NULL;
+	/* smp_mb(); */ /* atomic_set */
+
+ out:
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/aufs/wkq.h linux-2.6.31.4/fs/aufs/wkq.h
--- linux-2.6.31.4.orig/fs/aufs/wkq.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/wkq.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * workqueue for asynchronous/super-io operations
+ * todo: try new credentials management scheme
+ */
+
+#ifndef __AUFS_WKQ_H__
+#define __AUFS_WKQ_H__
+
+#ifdef __KERNEL__
+
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/aufs_type.h>
+
+struct super_block;
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * in the next operation, wait for the 'nowait' tasks in system-wide workqueue
+ */
+struct au_nowait_tasks {
+	atomic_t		nw_len;
+	wait_queue_head_t	nw_wq;
+};
+
+/* ---------------------------------------------------------------------- */
+
+typedef void (*au_wkq_func_t)(void *args);
+
+/* wkq flags */
+#define AuWkq_WAIT	1
+#define au_ftest_wkq(flags, name)	((flags) & AuWkq_##name)
+#define au_fset_wkq(flags, name)	{ (flags) |= AuWkq_##name; }
+#define au_fclr_wkq(flags, name)	{ (flags) &= ~AuWkq_##name; }
+
+/* wkq.c */
+int au_wkq_wait(au_wkq_func_t func, void *args);
+int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb);
+void au_nwt_init(struct au_nowait_tasks *nwt);
+int __init au_wkq_init(void);
+void au_wkq_fin(void);
+
+/* ---------------------------------------------------------------------- */
+
+static inline int au_test_wkq(struct task_struct *tsk)
+{
+	return !tsk->mm && !strcmp(tsk->comm, AUFS_WKQ_NAME);
+}
+
+static inline void au_nwt_done(struct au_nowait_tasks *nwt)
+{
+	if (!atomic_dec_return(&nwt->nw_len))
+		wake_up_all(&nwt->nw_wq);
+}
+
+static inline int au_nwt_flush(struct au_nowait_tasks *nwt)
+{
+	wait_event(nwt->nw_wq, !atomic_read(&nwt->nw_len));
+	return 0;
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_WKQ_H__ */
diff -Nur linux-2.6.31.4.orig/fs/aufs/xino.c linux-2.6.31.4/fs/aufs/xino.c
--- linux-2.6.31.4.orig/fs/aufs/xino.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/fs/aufs/xino.c	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,1200 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * external inode number translation table and bitmap
+ */
+
+#include <linux/file.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+ssize_t xino_fread(au_readf_t func, struct file *file, void *buf, size_t size,
+		   loff_t *pos)
+{
+	ssize_t err;
+	mm_segment_t oldfs;
+
+	oldfs = get_fs();
+	set_fs(KERNEL_DS);
+	do {
+		/* todo: signal_pending? */
+		err = func(file, (char __user *)buf, size, pos);
+	} while (err == -EAGAIN || err == -EINTR);
+	set_fs(oldfs);
+
+#if 0 /* reserved for future use */
+	if (err > 0)
+		fsnotify_access(file->f_dentry);
+#endif
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static ssize_t do_xino_fwrite(au_writef_t func, struct file *file, void *buf,
+			      size_t size, loff_t *pos)
+{
+	ssize_t err;
+	mm_segment_t oldfs;
+
+	oldfs = get_fs();
+	set_fs(KERNEL_DS);
+	lockdep_off();
+	do {
+		/* todo: signal_pending? */
+		err = func(file, (const char __user *)buf, size, pos);
+	} while (err == -EAGAIN || err == -EINTR);
+	lockdep_on();
+	set_fs(oldfs);
+
+#if 0 /* reserved for future use */
+	if (err > 0)
+		fsnotify_modify(file->f_dentry);
+#endif
+
+	return err;
+}
+
+struct do_xino_fwrite_args {
+	ssize_t *errp;
+	au_writef_t func;
+	struct file *file;
+	void *buf;
+	size_t size;
+	loff_t *pos;
+};
+
+static void call_do_xino_fwrite(void *args)
+{
+	struct do_xino_fwrite_args *a = args;
+	*a->errp = do_xino_fwrite(a->func, a->file, a->buf, a->size, a->pos);
+}
+
+ssize_t xino_fwrite(au_writef_t func, struct file *file, void *buf, size_t size,
+		    loff_t *pos)
+{
+	ssize_t err;
+
+	/* todo: signal block and no wkq? */
+	/* todo: new credential scheme */
+	/*
+	 * it breaks RLIMIT_FSIZE and normal user's limit,
+	 * users should care about quota and real 'filesystem full.'
+	 */
+	if (!au_test_wkq(current)) {
+		int wkq_err;
+		struct do_xino_fwrite_args args = {
+			.errp	= &err,
+			.func	= func,
+			.file	= file,
+			.buf	= buf,
+			.size	= size,
+			.pos	= pos
+		};
+
+		wkq_err = au_wkq_wait(call_do_xino_fwrite, &args);
+		if (unlikely(wkq_err))
+			err = wkq_err;
+	} else
+		err = do_xino_fwrite(func, file, buf, size, pos);
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * create a new xinofile at the same place/path as @base_file.
+ */
+struct file *au_xino_create2(struct file *base_file, struct file *copy_src)
+{
+	struct file *file;
+	struct dentry *base, *dentry, *parent;
+	struct inode *dir;
+	struct qstr *name;
+	int err;
+
+	base = base_file->f_dentry;
+	parent = base->d_parent; /* dir inode is locked */
+	dir = parent->d_inode;
+	IMustLock(dir);
+
+	file = ERR_PTR(-EINVAL);
+	name = &base->d_name;
+	dentry = vfsub_lookup_one_len(name->name, parent, name->len);
+	if (IS_ERR(dentry)) {
+		file = (void *)dentry;
+		AuErr("%.*s lookup err %ld\n", AuLNPair(name), PTR_ERR(dentry));
+		goto out;
+	}
+
+	/* no need to mnt_want_write() since we call dentry_open() later */
+	err = vfs_create(dir, dentry, S_IRUGO | S_IWUGO, NULL);
+	if (unlikely(err)) {
+		file = ERR_PTR(err);
+		AuErr("%.*s create err %d\n", AuLNPair(name), err);
+		goto out_dput;
+	}
+
+	file = dentry_open(dget(dentry), mntget(base_file->f_vfsmnt),
+			   O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE,
+			   current_cred());
+	if (IS_ERR(file)) {
+		AuErr("%.*s open err %ld\n", AuLNPair(name), PTR_ERR(file));
+		goto out_dput;
+	}
+
+	err = vfsub_unlink(dir, &file->f_path, /*force*/0);
+	if (unlikely(err)) {
+		AuErr("%.*s unlink err %d\n", AuLNPair(name), err);
+		goto out_fput;
+	}
+
+	if (copy_src) {
+		/* no one can touch copy_src xino */
+		err = au_copy_file(file, copy_src,
+				   i_size_read(copy_src->f_dentry->d_inode));
+		if (unlikely(err)) {
+			AuErr("%.*s copy err %d\n", AuLNPair(name), err);
+			goto out_fput;
+		}
+	}
+	goto out_dput; /* success */
+
+ out_fput:
+	fput(file);
+	file = ERR_PTR(err);
+ out_dput:
+	dput(dentry);
+ out:
+	return file;
+}
+
+struct au_xino_lock_dir {
+	struct au_hinode *hdir;
+	struct dentry *parent;
+	struct mutex *mtx;
+};
+
+static void au_xino_lock_dir(struct super_block *sb, struct file *xino,
+			     struct au_xino_lock_dir *ldir)
+{
+	aufs_bindex_t brid, bindex;
+
+	ldir->hdir = NULL;
+	bindex = -1;
+	brid = au_xino_brid(sb);
+	if (brid >= 0)
+		bindex = au_br_index(sb, brid);
+	if (bindex >= 0) {
+		ldir->hdir = au_hi(sb->s_root->d_inode, bindex);
+		au_hin_imtx_lock_nested(ldir->hdir, AuLsc_I_PARENT);
+	} else {
+		ldir->parent = dget_parent(xino->f_dentry);
+		ldir->mtx = &ldir->parent->d_inode->i_mutex;
+		mutex_lock_nested(ldir->mtx, AuLsc_I_PARENT);
+	}
+}
+
+static void au_xino_unlock_dir(struct au_xino_lock_dir *ldir)
+{
+	if (ldir->hdir)
+		au_hin_imtx_unlock(ldir->hdir);
+	else {
+		mutex_unlock(ldir->mtx);
+		dput(ldir->parent);
+	}
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* trucate xino files asynchronously */
+
+int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex)
+{
+	int err;
+	aufs_bindex_t bi, bend;
+	struct au_branch *br;
+	struct file *new_xino, *file;
+	struct super_block *h_sb;
+	struct au_xino_lock_dir ldir;
+
+	err = -EINVAL;
+	bend = au_sbend(sb);
+	if (unlikely(bindex < 0 || bend < bindex))
+		goto out;
+	br = au_sbr(sb, bindex);
+	file = br->br_xino.xi_file;
+	if (!file)
+		goto out;
+
+	au_xino_lock_dir(sb, file, &ldir);
+	/* mnt_want_write() is unnecessary here */
+	new_xino = au_xino_create2(file, file);
+	au_xino_unlock_dir(&ldir);
+	err = PTR_ERR(new_xino);
+	if (IS_ERR(new_xino))
+		goto out;
+	err = 0;
+	fput(file);
+	br->br_xino.xi_file = new_xino;
+
+	h_sb = br->br_mnt->mnt_sb;
+	for (bi = 0; bi <= bend; bi++) {
+		if (unlikely(bi == bindex))
+			continue;
+		br = au_sbr(sb, bi);
+		if (br->br_mnt->mnt_sb != h_sb)
+			continue;
+
+		fput(br->br_xino.xi_file);
+		br->br_xino.xi_file = new_xino;
+		get_file(new_xino);
+	}
+
+ out:
+	return err;
+}
+
+struct xino_do_trunc_args {
+	struct super_block *sb;
+	struct au_branch *br;
+};
+
+static void xino_do_trunc(void *_args)
+{
+	struct xino_do_trunc_args *args = _args;
+	struct super_block *sb;
+	struct au_branch *br;
+	struct inode *dir;
+	int err;
+	aufs_bindex_t bindex;
+
+	err = 0;
+	sb = args->sb;
+	dir = sb->s_root->d_inode;
+	br = args->br;
+
+	si_noflush_write_lock(sb);
+	ii_read_lock_parent(dir);
+	bindex = au_br_index(sb, br->br_id);
+	err = au_xino_trunc(sb, bindex);
+	if (!err
+	    && br->br_xino.xi_file->f_dentry->d_inode->i_blocks
+	    >= br->br_xino_upper)
+		br->br_xino_upper += AUFS_XINO_TRUNC_STEP;
+
+	ii_read_unlock(dir);
+	if (unlikely(err))
+		AuWarn("err b%d, (%d)\n", bindex, err);
+	atomic_dec(&br->br_xino_running);
+	atomic_dec(&br->br_count);
+	au_nwt_done(&au_sbi(sb)->si_nowait);
+	si_write_unlock(sb);
+	kfree(args);
+}
+
+static void xino_try_trunc(struct super_block *sb, struct au_branch *br)
+{
+	struct xino_do_trunc_args *args;
+	int wkq_err;
+
+	if (br->br_xino.xi_file->f_dentry->d_inode->i_blocks
+	    < br->br_xino_upper)
+		return;
+
+	if (atomic_inc_return(&br->br_xino_running) > 1)
+		goto out;
+
+	/* lock and kfree() will be called in trunc_xino() */
+	args = kmalloc(sizeof(*args), GFP_NOFS);
+	if (unlikely(!args)) {
+		AuErr1("no memory\n");
+		goto out_args;
+	}
+
+	atomic_inc_return(&br->br_count);
+	args->sb = sb;
+	args->br = br;
+	wkq_err = au_wkq_nowait(xino_do_trunc, args, sb);
+	if (!wkq_err)
+		return; /* success */
+
+	AuErr("wkq %d\n", wkq_err);
+	atomic_dec_return(&br->br_count);
+
+ out_args:
+	kfree(args);
+ out:
+	atomic_dec_return(&br->br_xino_running);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_xino_do_write(au_writef_t write, struct file *file,
+			    ino_t h_ino, ino_t ino)
+{
+	loff_t pos;
+	ssize_t sz;
+
+	pos = h_ino;
+	if (unlikely(au_loff_max / sizeof(ino) - 1 < pos)) {
+		AuIOErr1("too large hi%lu\n", (unsigned long)h_ino);
+		return -EFBIG;
+	}
+	pos *= sizeof(ino);
+	sz = xino_fwrite(write, file, &ino, sizeof(ino), &pos);
+	if (sz == sizeof(ino))
+		return 0; /* success */
+
+	AuIOErr("write failed (%zd)\n", sz);
+	return -EIO;
+}
+
+/*
+ * write @ino to the xinofile for the specified branch{@sb, @bindex}
+ * at the position of @h_ino.
+ * even if @ino is zero, it is written to the xinofile and means no entry.
+ * if the size of the xino file on a specific filesystem exceeds the watermark,
+ * try truncating it.
+ */
+int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		  ino_t ino)
+{
+	int err;
+	unsigned int mnt_flags;
+	struct au_branch *br;
+
+	BUILD_BUG_ON(sizeof(long long) != sizeof(au_loff_max)
+		     || ((loff_t)-1) > 0);
+	SiMustAnyLock(sb);
+
+	mnt_flags = au_mntflags(sb);
+	if (!au_opt_test(mnt_flags, XINO))
+		return 0;
+
+	br = au_sbr(sb, bindex);
+	err = au_xino_do_write(au_sbi(sb)->si_xwrite, br->br_xino.xi_file,
+			       h_ino, ino);
+	if (!err) {
+		if (au_opt_test(mnt_flags, TRUNC_XINO)
+		    && au_test_fs_trunc_xino(br->br_mnt->mnt_sb))
+			xino_try_trunc(sb, br);
+		return 0; /* success */
+	}
+
+	AuIOErr("write failed (%d)\n", err);
+	return -EIO;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* aufs inode number bitmap */
+
+static const int page_bits = (int)PAGE_SIZE * BITS_PER_BYTE;
+static ino_t xib_calc_ino(unsigned long pindex, int bit)
+{
+	ino_t ino;
+
+	AuDebugOn(bit < 0 || page_bits <= bit);
+	ino = AUFS_FIRST_INO + pindex * page_bits + bit;
+	return ino;
+}
+
+static void xib_calc_bit(ino_t ino, unsigned long *pindex, int *bit)
+{
+	AuDebugOn(ino < AUFS_FIRST_INO);
+	ino -= AUFS_FIRST_INO;
+	*pindex = ino / page_bits;
+	*bit = ino % page_bits;
+}
+
+static int xib_pindex(struct super_block *sb, unsigned long pindex)
+{
+	int err;
+	loff_t pos;
+	ssize_t sz;
+	struct au_sbinfo *sbinfo;
+	struct file *xib;
+	unsigned long *p;
+
+	sbinfo = au_sbi(sb);
+	MtxMustLock(&sbinfo->si_xib_mtx);
+	AuDebugOn(pindex > ULONG_MAX / PAGE_SIZE
+		  || !au_opt_test(sbinfo->si_mntflags, XINO));
+
+	if (pindex == sbinfo->si_xib_last_pindex)
+		return 0;
+
+	xib = sbinfo->si_xib;
+	p = sbinfo->si_xib_buf;
+	pos = sbinfo->si_xib_last_pindex;
+	pos *= PAGE_SIZE;
+	sz = xino_fwrite(sbinfo->si_xwrite, xib, p, PAGE_SIZE, &pos);
+	if (unlikely(sz != PAGE_SIZE))
+		goto out;
+
+	pos = pindex;
+	pos *= PAGE_SIZE;
+	if (i_size_read(xib->f_dentry->d_inode) >= pos + PAGE_SIZE)
+		sz = xino_fread(sbinfo->si_xread, xib, p, PAGE_SIZE, &pos);
+	else {
+		memset(p, 0, PAGE_SIZE);
+		sz = xino_fwrite(sbinfo->si_xwrite, xib, p, PAGE_SIZE, &pos);
+	}
+	if (sz == PAGE_SIZE) {
+		sbinfo->si_xib_last_pindex = pindex;
+		return 0; /* success */
+	}
+
+ out:
+	AuIOErr1("write failed (%zd)\n", sz);
+	err = sz;
+	if (sz >= 0)
+		err = -EIO;
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_xino_write0(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		   ino_t ino)
+{
+	int err, bit;
+	unsigned long pindex;
+	struct au_sbinfo *sbinfo;
+
+	if (!au_opt_test(au_mntflags(sb), XINO))
+		return 0;
+
+	err = 0;
+	if (ino) {
+		sbinfo = au_sbi(sb);
+		xib_calc_bit(ino, &pindex, &bit);
+		AuDebugOn(page_bits <= bit);
+		mutex_lock(&sbinfo->si_xib_mtx);
+		err = xib_pindex(sb, pindex);
+		if (!err) {
+			clear_bit(bit, sbinfo->si_xib_buf);
+			sbinfo->si_xib_next_bit = bit;
+		}
+		mutex_unlock(&sbinfo->si_xib_mtx);
+	}
+
+	if (!err)
+		err = au_xino_write(sb, bindex, h_ino, 0);
+	return err;
+}
+
+/* get an unused inode number from bitmap */
+ino_t au_xino_new_ino(struct super_block *sb)
+{
+	ino_t ino;
+	unsigned long *p, pindex, ul, pend;
+	struct au_sbinfo *sbinfo;
+	struct file *file;
+	int free_bit, err;
+
+	if (!au_opt_test(au_mntflags(sb), XINO))
+		return iunique(sb, AUFS_FIRST_INO);
+
+	sbinfo = au_sbi(sb);
+	mutex_lock(&sbinfo->si_xib_mtx);
+	p = sbinfo->si_xib_buf;
+	free_bit = sbinfo->si_xib_next_bit;
+	if (free_bit < page_bits && !test_bit(free_bit, p))
+		goto out; /* success */
+	free_bit = find_first_zero_bit(p, page_bits);
+	if (free_bit < page_bits)
+		goto out; /* success */
+
+	pindex = sbinfo->si_xib_last_pindex;
+	for (ul = pindex - 1; ul < ULONG_MAX; ul--) {
+		err = xib_pindex(sb, ul);
+		if (unlikely(err))
+			goto out_err;
+		free_bit = find_first_zero_bit(p, page_bits);
+		if (free_bit < page_bits)
+			goto out; /* success */
+	}
+
+	file = sbinfo->si_xib;
+	pend = i_size_read(file->f_dentry->d_inode) / PAGE_SIZE;
+	for (ul = pindex + 1; ul <= pend; ul++) {
+		err = xib_pindex(sb, ul);
+		if (unlikely(err))
+			goto out_err;
+		free_bit = find_first_zero_bit(p, page_bits);
+		if (free_bit < page_bits)
+			goto out; /* success */
+	}
+	BUG();
+
+ out:
+	set_bit(free_bit, p);
+	sbinfo->si_xib_next_bit++;
+	pindex = sbinfo->si_xib_last_pindex;
+	mutex_unlock(&sbinfo->si_xib_mtx);
+	ino = xib_calc_ino(pindex, free_bit);
+	AuDbg("i%lu\n", (unsigned long)ino);
+	return ino;
+ out_err:
+	mutex_unlock(&sbinfo->si_xib_mtx);
+	AuDbg("i0\n");
+	return 0;
+}
+
+/*
+ * read @ino from xinofile for the specified branch{@sb, @bindex}
+ * at the position of @h_ino.
+ * if @ino does not exist and @do_new is true, get new one.
+ */
+int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+		 ino_t *ino)
+{
+	int err;
+	ssize_t sz;
+	loff_t pos;
+	struct file *file;
+	struct au_sbinfo *sbinfo;
+
+	*ino = 0;
+	if (!au_opt_test(au_mntflags(sb), XINO))
+		return 0; /* no xino */
+
+	err = 0;
+	sbinfo = au_sbi(sb);
+	pos = h_ino;
+	if (unlikely(au_loff_max / sizeof(*ino) - 1 < pos)) {
+		AuIOErr1("too large hi%lu\n", (unsigned long)h_ino);
+		return -EFBIG;
+	}
+	pos *= sizeof(*ino);
+
+	file = au_sbr(sb, bindex)->br_xino.xi_file;
+	if (i_size_read(file->f_dentry->d_inode) < pos + sizeof(*ino))
+		return 0; /* no ino */
+
+	sz = xino_fread(sbinfo->si_xread, file, ino, sizeof(*ino), &pos);
+	if (sz == sizeof(*ino))
+		return 0; /* success */
+
+	err = sz;
+	if (unlikely(sz >= 0)) {
+		err = -EIO;
+		AuIOErr("xino read error (%zd)\n", sz);
+	}
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* create and set a new xino file */
+
+struct file *au_xino_create(struct super_block *sb, char *fname, int silent)
+{
+	struct file *file;
+	struct dentry *h_parent, *d;
+	struct inode *h_dir;
+	int err;
+
+	/*
+	 * at mount-time, and the xino file is the default path,
+	 * hinotify is disabled so we have no inotify events to ignore.
+	 * when a user specified the xino, we cannot get au_hdir to be ignored.
+	 */
+	file = vfsub_filp_open(fname, O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE,
+			       S_IRUGO | S_IWUGO);
+	if (IS_ERR(file)) {
+		if (!silent)
+			AuErr("open %s(%ld)\n", fname, PTR_ERR(file));
+		return file;
+	}
+
+	/* keep file count */
+	h_parent = dget_parent(file->f_dentry);
+	h_dir = h_parent->d_inode;
+	mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+	/* mnt_want_write() is unnecessary here */
+	err = vfsub_unlink(h_dir, &file->f_path, /*force*/0);
+	mutex_unlock(&h_dir->i_mutex);
+	dput(h_parent);
+	if (unlikely(err)) {
+		if (!silent)
+			AuErr("unlink %s(%d)\n", fname, err);
+		goto out;
+	}
+
+	err = -EINVAL;
+	d = file->f_dentry;
+	if (unlikely(sb == d->d_sb)) {
+		if (!silent)
+			AuErr("%s must be outside\n", fname);
+		goto out;
+	}
+	if (unlikely(au_test_fs_bad_xino(d->d_sb))) {
+		if (!silent)
+			AuErr("xino doesn't support %s(%s)\n",
+			      fname, au_sbtype(d->d_sb));
+		goto out;
+	}
+	return file; /* success */
+
+ out:
+	fput(file);
+	file = ERR_PTR(err);
+	return file;
+}
+
+/*
+ * find another branch who is on the same filesystem of the specified
+ * branch{@btgt}. search until @bend.
+ */
+static int is_sb_shared(struct super_block *sb, aufs_bindex_t btgt,
+			aufs_bindex_t bend)
+{
+	aufs_bindex_t bindex;
+	struct super_block *tgt_sb = au_sbr_sb(sb, btgt);
+
+	for (bindex = 0; bindex < btgt; bindex++)
+		if (unlikely(tgt_sb == au_sbr_sb(sb, bindex)))
+			return bindex;
+	for (bindex++; bindex <= bend; bindex++)
+		if (unlikely(tgt_sb == au_sbr_sb(sb, bindex)))
+			return bindex;
+	return -1;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * initialize the xinofile for the specified branch @br
+ * at the place/path where @base_file indicates.
+ * test whether another branch is on the same filesystem or not,
+ * if @do_test is true.
+ */
+int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t h_ino,
+	       struct file *base_file, int do_test)
+{
+	int err;
+	ino_t ino;
+	aufs_bindex_t bend, bindex;
+	struct au_branch *shared_br, *b;
+	struct file *file;
+	struct super_block *tgt_sb;
+
+	shared_br = NULL;
+	bend = au_sbend(sb);
+	if (do_test) {
+		tgt_sb = br->br_mnt->mnt_sb;
+		for (bindex = 0; bindex <= bend; bindex++) {
+			b = au_sbr(sb, bindex);
+			if (tgt_sb == b->br_mnt->mnt_sb) {
+				shared_br = b;
+				break;
+			}
+		}
+	}
+
+	if (!shared_br || !shared_br->br_xino.xi_file) {
+		struct au_xino_lock_dir ldir;
+
+		au_xino_lock_dir(sb, base_file, &ldir);
+		/* mnt_want_write() is unnecessary here */
+		file = au_xino_create2(base_file, NULL);
+		au_xino_unlock_dir(&ldir);
+		err = PTR_ERR(file);
+		if (IS_ERR(file))
+			goto out;
+		br->br_xino.xi_file = file;
+	} else {
+		br->br_xino.xi_file = shared_br->br_xino.xi_file;
+		get_file(br->br_xino.xi_file);
+	}
+
+	ino = AUFS_ROOT_INO;
+	err = au_xino_do_write(au_sbi(sb)->si_xwrite, br->br_xino.xi_file,
+			       h_ino, ino);
+	if (!err)
+		return 0; /* success */
+
+
+ out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* trucate a xino bitmap file */
+
+/* todo: slow */
+static int do_xib_restore(struct super_block *sb, struct file *file, void *page)
+{
+	int err, bit;
+	ssize_t sz;
+	unsigned long pindex;
+	loff_t pos, pend;
+	struct au_sbinfo *sbinfo;
+	au_readf_t func;
+	ino_t *ino;
+	unsigned long *p;
+
+	err = 0;
+	sbinfo = au_sbi(sb);
+	MtxMustLock(&sbinfo->si_xib_mtx);
+	p = sbinfo->si_xib_buf;
+	func = sbinfo->si_xread;
+	pend = i_size_read(file->f_dentry->d_inode);
+	pos = 0;
+	while (pos < pend) {
+		sz = xino_fread(func, file, page, PAGE_SIZE, &pos);
+		err = sz;
+		if (unlikely(sz <= 0))
+			goto out;
+
+		err = 0;
+		for (ino = page; sz > 0; ino++, sz -= sizeof(ino)) {
+			if (unlikely(*ino < AUFS_FIRST_INO))
+				continue;
+
+			xib_calc_bit(*ino, &pindex, &bit);
+			AuDebugOn(page_bits <= bit);
+			err = xib_pindex(sb, pindex);
+			if (!err)
+				set_bit(bit, p);
+			else
+				goto out;
+		}
+	}
+
+ out:
+	return err;
+}
+
+static int xib_restore(struct super_block *sb)
+{
+	int err;
+	aufs_bindex_t bindex, bend;
+	void *page;
+
+	err = -ENOMEM;
+	page = (void *)__get_free_page(GFP_NOFS);
+	if (unlikely(!page))
+		goto out;
+
+	err = 0;
+	bend = au_sbend(sb);
+	for (bindex = 0; !err && bindex <= bend; bindex++)
+		if (!bindex || is_sb_shared(sb, bindex, bindex - 1) < 0)
+			err = do_xib_restore
+				(sb, au_sbr(sb, bindex)->br_xino.xi_file, page);
+		else
+			AuDbg("b%d\n", bindex);
+	free_page((unsigned long)page);
+
+ out:
+	return err;
+}
+
+int au_xib_trunc(struct super_block *sb)
+{
+	int err;
+	ssize_t sz;
+	loff_t pos;
+	struct au_xino_lock_dir ldir;
+	struct au_sbinfo *sbinfo;
+	unsigned long *p;
+	struct file *file;
+
+	SiMustWriteLock(sb);
+
+	err = 0;
+	sbinfo = au_sbi(sb);
+	if (!au_opt_test(sbinfo->si_mntflags, XINO))
+		goto out;
+
+	file = sbinfo->si_xib;
+	if (i_size_read(file->f_dentry->d_inode) <= PAGE_SIZE)
+		goto out;
+
+	au_xino_lock_dir(sb, file, &ldir);
+	/* mnt_want_write() is unnecessary here */
+	file = au_xino_create2(sbinfo->si_xib, NULL);
+	au_xino_unlock_dir(&ldir);
+	err = PTR_ERR(file);
+	if (IS_ERR(file))
+		goto out;
+	fput(sbinfo->si_xib);
+	sbinfo->si_xib = file;
+
+	p = sbinfo->si_xib_buf;
+	memset(p, 0, PAGE_SIZE);
+	pos = 0;
+	sz = xino_fwrite(sbinfo->si_xwrite, sbinfo->si_xib, p, PAGE_SIZE, &pos);
+	if (unlikely(sz != PAGE_SIZE)) {
+		err = sz;
+		AuIOErr("err %d\n", err);
+		if (sz >= 0)
+			err = -EIO;
+		goto out;
+	}
+
+	mutex_lock(&sbinfo->si_xib_mtx);
+	/* mnt_want_write() is unnecessary here */
+	err = xib_restore(sb);
+	mutex_unlock(&sbinfo->si_xib_mtx);
+
+out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * xino mount option handlers
+ */
+static au_readf_t find_readf(struct file *h_file)
+{
+	const struct file_operations *fop = h_file->f_op;
+
+	if (fop) {
+		if (fop->read)
+			return fop->read;
+		if (fop->aio_read)
+			return do_sync_read;
+	}
+	return ERR_PTR(-ENOSYS);
+}
+
+static au_writef_t find_writef(struct file *h_file)
+{
+	const struct file_operations *fop = h_file->f_op;
+
+	if (fop) {
+		if (fop->write)
+			return fop->write;
+		if (fop->aio_write)
+			return do_sync_write;
+	}
+	return ERR_PTR(-ENOSYS);
+}
+
+/* xino bitmap */
+static void xino_clear_xib(struct super_block *sb)
+{
+	struct au_sbinfo *sbinfo;
+
+	SiMustWriteLock(sb);
+
+	sbinfo = au_sbi(sb);
+	sbinfo->si_xread = NULL;
+	sbinfo->si_xwrite = NULL;
+	if (sbinfo->si_xib)
+		fput(sbinfo->si_xib);
+	sbinfo->si_xib = NULL;
+	free_page((unsigned long)sbinfo->si_xib_buf);
+	sbinfo->si_xib_buf = NULL;
+}
+
+static int au_xino_set_xib(struct super_block *sb, struct file *base)
+{
+	int err;
+	loff_t pos;
+	struct au_sbinfo *sbinfo;
+	struct file *file;
+
+	SiMustWriteLock(sb);
+
+	sbinfo = au_sbi(sb);
+	file = au_xino_create2(base, sbinfo->si_xib);
+	err = PTR_ERR(file);
+	if (IS_ERR(file))
+		goto out;
+	if (sbinfo->si_xib)
+		fput(sbinfo->si_xib);
+	sbinfo->si_xib = file;
+	sbinfo->si_xread = find_readf(file);
+	sbinfo->si_xwrite = find_writef(file);
+
+	err = -ENOMEM;
+	if (!sbinfo->si_xib_buf)
+		sbinfo->si_xib_buf = (void *)get_zeroed_page(GFP_NOFS);
+	if (unlikely(!sbinfo->si_xib_buf))
+		goto out_unset;
+
+	sbinfo->si_xib_last_pindex = 0;
+	sbinfo->si_xib_next_bit = 0;
+	if (i_size_read(file->f_dentry->d_inode) < PAGE_SIZE) {
+		pos = 0;
+		err = xino_fwrite(sbinfo->si_xwrite, file, sbinfo->si_xib_buf,
+				  PAGE_SIZE, &pos);
+		if (unlikely(err != PAGE_SIZE))
+			goto out_free;
+	}
+	err = 0;
+	goto out; /* success */
+
+ out_free:
+	free_page((unsigned long)sbinfo->si_xib_buf);
+	sbinfo->si_xib_buf = NULL;
+	if (err >= 0)
+		err = -EIO;
+ out_unset:
+	fput(sbinfo->si_xib);
+	sbinfo->si_xib = NULL;
+	sbinfo->si_xread = NULL;
+	sbinfo->si_xwrite = NULL;
+ out:
+	return err;
+}
+
+/* xino for each branch */
+static void xino_clear_br(struct super_block *sb)
+{
+	aufs_bindex_t bindex, bend;
+	struct au_branch *br;
+
+	bend = au_sbend(sb);
+	for (bindex = 0; bindex <= bend; bindex++) {
+		br = au_sbr(sb, bindex);
+		if (!br || !br->br_xino.xi_file)
+			continue;
+
+		fput(br->br_xino.xi_file);
+		br->br_xino.xi_file = NULL;
+	}
+}
+
+static int au_xino_set_br(struct super_block *sb, struct file *base)
+{
+	int err;
+	ino_t ino;
+	aufs_bindex_t bindex, bend, bshared;
+	struct {
+		struct file *old, *new;
+	} *fpair, *p;
+	struct au_branch *br;
+	struct inode *inode;
+	au_writef_t writef;
+
+	SiMustWriteLock(sb);
+
+	err = -ENOMEM;
+	bend = au_sbend(sb);
+	fpair = kcalloc(bend + 1, sizeof(*fpair), GFP_NOFS);
+	if (unlikely(!fpair))
+		goto out;
+
+	inode = sb->s_root->d_inode;
+	ino = AUFS_ROOT_INO;
+	writef = au_sbi(sb)->si_xwrite;
+	for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++) {
+		br = au_sbr(sb, bindex);
+		bshared = is_sb_shared(sb, bindex, bindex - 1);
+		if (bshared >= 0) {
+			/* shared xino */
+			*p = fpair[bshared];
+			get_file(p->new);
+		}
+
+		if (!p->new) {
+			/* new xino */
+			p->old = br->br_xino.xi_file;
+			p->new = au_xino_create2(base, br->br_xino.xi_file);
+			err = PTR_ERR(p->new);
+			if (IS_ERR(p->new)) {
+				p->new = NULL;
+				goto out_pair;
+			}
+		}
+
+		err = au_xino_do_write(writef, p->new,
+				       au_h_iptr(inode, bindex)->i_ino, ino);
+		if (unlikely(err))
+			goto out_pair;
+	}
+
+	for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++) {
+		br = au_sbr(sb, bindex);
+		if (br->br_xino.xi_file)
+			fput(br->br_xino.xi_file);
+		get_file(p->new);
+		br->br_xino.xi_file = p->new;
+	}
+
+ out_pair:
+	for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++)
+		if (p->new)
+			fput(p->new);
+		else
+			break;
+	kfree(fpair);
+ out:
+	return err;
+}
+
+void au_xino_clr(struct super_block *sb)
+{
+	struct au_sbinfo *sbinfo;
+
+	au_xigen_clr(sb);
+	xino_clear_xib(sb);
+	xino_clear_br(sb);
+	sbinfo = au_sbi(sb);
+	/* lvalue, do not call au_mntflags() */
+	au_opt_clr(sbinfo->si_mntflags, XINO);
+}
+
+int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount)
+{
+	int err, skip;
+	struct dentry *parent, *cur_parent;
+	struct qstr *dname, *cur_name;
+	struct file *cur_xino;
+	struct inode *dir;
+	struct au_sbinfo *sbinfo;
+
+	SiMustWriteLock(sb);
+
+	err = 0;
+	sbinfo = au_sbi(sb);
+	parent = dget_parent(xino->file->f_dentry);
+	if (remount) {
+		skip = 0;
+		dname = &xino->file->f_dentry->d_name;
+		cur_xino = sbinfo->si_xib;
+		if (cur_xino) {
+			cur_parent = dget_parent(cur_xino->f_dentry);
+			cur_name = &cur_xino->f_dentry->d_name;
+			skip = (cur_parent == parent
+				&& dname->len == cur_name->len
+				&& !memcmp(dname->name, cur_name->name,
+					   dname->len));
+			dput(cur_parent);
+		}
+		if (skip)
+			goto out;
+	}
+
+	au_opt_set(sbinfo->si_mntflags, XINO);
+	dir = parent->d_inode;
+	mutex_lock_nested(&dir->i_mutex, AuLsc_I_PARENT);
+	/* mnt_want_write() is unnecessary here */
+	err = au_xino_set_xib(sb, xino->file);
+	if (!err)
+		err = au_xigen_set(sb, xino->file);
+	if (!err)
+		err = au_xino_set_br(sb, xino->file);
+	mutex_unlock(&dir->i_mutex);
+	if (!err)
+		goto out; /* success */
+
+	/* reset all */
+	AuIOErr("failed creating xino(%d).\n", err);
+
+ out:
+	dput(parent);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * create a xinofile at the default place/path.
+ */
+struct file *au_xino_def(struct super_block *sb)
+{
+	struct file *file;
+	char *page, *p;
+	struct au_branch *br;
+	struct super_block *h_sb;
+	struct path path;
+	aufs_bindex_t bend, bindex, bwr;
+
+	br = NULL;
+	bend = au_sbend(sb);
+	bwr = -1;
+	for (bindex = 0; bindex <= bend; bindex++) {
+		br = au_sbr(sb, bindex);
+		if (au_br_writable(br->br_perm)
+		    && !au_test_fs_bad_xino(br->br_mnt->mnt_sb)) {
+			bwr = bindex;
+			break;
+		}
+	}
+
+	if (bwr >= 0) {
+		file = ERR_PTR(-ENOMEM);
+		page = __getname();
+		if (unlikely(!page))
+			goto out;
+		path.mnt = br->br_mnt;
+		path.dentry = au_h_dptr(sb->s_root, bwr);
+		p = d_path(&path, page, PATH_MAX - sizeof(AUFS_XINO_FNAME));
+		file = (void *)p;
+		if (!IS_ERR(p)) {
+			strcat(p, "/" AUFS_XINO_FNAME);
+			AuDbg("%s\n", p);
+			file = au_xino_create(sb, p, /*silent*/0);
+			if (!IS_ERR(file))
+				au_xino_brid_set(sb, br->br_id);
+		}
+		__putname(page);
+	} else {
+		file = au_xino_create(sb, AUFS_XINO_DEFPATH, /*silent*/0);
+		if (IS_ERR(file))
+			goto out;
+		h_sb = file->f_dentry->d_sb;
+		if (unlikely(au_test_fs_bad_xino(h_sb))) {
+			AuErr("xino doesn't support %s(%s)\n",
+			      AUFS_XINO_DEFPATH, au_sbtype(h_sb));
+			fput(file);
+			file = ERR_PTR(-EINVAL);
+		}
+		if (!IS_ERR(file))
+			au_xino_brid_set(sb, -1);
+	}
+
+ out:
+	return file;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_xino_path(struct seq_file *seq, struct file *file)
+{
+	int err;
+
+	err = au_seq_path(seq, &file->f_path);
+	if (unlikely(err < 0))
+		goto out;
+
+	err = 0;
+#define Deleted "\\040(deleted)"
+	seq->count -= sizeof(Deleted) - 1;
+	AuDebugOn(memcmp(seq->buf + seq->count, Deleted,
+			 sizeof(Deleted) - 1));
+#undef Deleted
+
+ out:
+	return err;
+}
diff -Nur linux-2.6.31.4.orig/fs/Kconfig linux-2.6.31.4/fs/Kconfig
--- linux-2.6.31.4.orig/fs/Kconfig	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/fs/Kconfig	2009-10-18 11:26:53.000000000 +0200
@@ -187,6 +187,7 @@
 source "fs/ufs/Kconfig"
 source "fs/exofs/Kconfig"
 source "fs/nilfs2/Kconfig"
+source "fs/aufs/Kconfig"
 
 endif # MISC_FILESYSTEMS
 
diff -Nur linux-2.6.31.4.orig/fs/Makefile linux-2.6.31.4/fs/Makefile
--- linux-2.6.31.4.orig/fs/Makefile	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/fs/Makefile	2009-10-18 11:26:01.000000000 +0200
@@ -85,6 +85,7 @@
 obj-$(CONFIG_HFS_FS)		+= hfs/
 obj-$(CONFIG_ECRYPT_FS)		+= ecryptfs/
 obj-$(CONFIG_VXFS_FS)		+= freevxfs/
+obj-$(CONFIG_AUFS_FS)           += aufs/
 obj-$(CONFIG_NFS_FS)		+= nfs/
 obj-$(CONFIG_EXPORTFS)		+= exportfs/
 obj-$(CONFIG_NFSD)		+= nfsd/
diff -Nur linux-2.6.31.4.orig/fs/namei.c linux-2.6.31.4/fs/namei.c
--- linux-2.6.31.4.orig/fs/namei.c	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/fs/namei.c	2009-10-18 11:26:01.000000000 +0200
@@ -337,6 +337,7 @@
 
 	return 0;
 }
+EXPORT_SYMBOL(deny_write_access);
 
 /**
  * path_get - get a reference to a path
@@ -1219,7 +1220,7 @@
  * needs parent already locked. Doesn't follow mounts.
  * SMP-safe.
  */
-static struct dentry *lookup_hash(struct nameidata *nd)
+struct dentry *lookup_hash(struct nameidata *nd)
 {
 	int err;
 
@@ -1228,8 +1229,9 @@
 		return ERR_PTR(err);
 	return __lookup_hash(&nd->last, nd->path.dentry, nd);
 }
+EXPORT_SYMBOL(lookup_hash);
 
-static int __lookup_one_len(const char *name, struct qstr *this,
+int __lookup_one_len(const char *name, struct qstr *this,
 		struct dentry *base, int len)
 {
 	unsigned long hash;
@@ -1250,6 +1252,7 @@
 	this->hash = end_name_hash(hash);
 	return 0;
 }
+EXPORT_SYMBOL(__lookup_one_len);
 
 /**
  * lookup_one_len - filesystem helper to lookup single pathname component
diff -Nur linux-2.6.31.4.orig/fs/namespace.c linux-2.6.31.4/fs/namespace.c
--- linux-2.6.31.4.orig/fs/namespace.c	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/fs/namespace.c	2009-10-18 11:26:01.000000000 +0200
@@ -39,6 +39,7 @@
 
 /* spinlock for vfsmount related operations, inplace of dcache_lock */
 __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
+EXPORT_SYMBOL(vfsmount_lock);
 
 static int event;
 static DEFINE_IDA(mnt_id_ida);
diff -Nur linux-2.6.31.4.orig/fs/open.c linux-2.6.31.4/fs/open.c
--- linux-2.6.31.4.orig/fs/open.c	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/fs/open.c	2009-10-18 11:26:01.000000000 +0200
@@ -221,6 +221,7 @@
 	mutex_unlock(&dentry->d_inode->i_mutex);
 	return err;
 }
+EXPORT_SYMBOL(do_truncate);
 
 static long do_sys_truncate(const char __user *pathname, loff_t length)
 {
diff -Nur linux-2.6.31.4.orig/fs/splice.c linux-2.6.31.4/fs/splice.c
--- linux-2.6.31.4.orig/fs/splice.c	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/fs/splice.c	2009-10-18 11:26:01.000000000 +0200
@@ -1057,8 +1057,8 @@
 /*
  * Attempt to initiate a splice from pipe to file.
  */
-static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
-			   loff_t *ppos, size_t len, unsigned int flags)
+long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
+		    loff_t *ppos, size_t len, unsigned int flags)
 {
 	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *,
 				loff_t *, size_t, unsigned int);
@@ -1080,13 +1080,14 @@
 
 	return splice_write(pipe, out, ppos, len, flags);
 }
+EXPORT_SYMBOL(do_splice_from);
 
 /*
  * Attempt to initiate a splice from a file to a pipe.
  */
-static long do_splice_to(struct file *in, loff_t *ppos,
-			 struct pipe_inode_info *pipe, size_t len,
-			 unsigned int flags)
+long do_splice_to(struct file *in, loff_t *ppos,
+		  struct pipe_inode_info *pipe, size_t len,
+		  unsigned int flags)
 {
 	ssize_t (*splice_read)(struct file *, loff_t *,
 			       struct pipe_inode_info *, size_t, unsigned int);
@@ -1105,6 +1106,7 @@
 
 	return splice_read(in, ppos, pipe, len, flags);
 }
+EXPORT_SYMBOL(do_splice_to);
 
 /**
  * splice_direct_to_actor - splices data directly between two non-pipes
diff -Nur linux-2.6.31.4.orig/include/linux/aufs_type.h linux-2.6.31.4/include/linux/aufs_type.h
--- linux-2.6.31.4.orig/include/linux/aufs_type.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.31.4/include/linux/aufs_type.h	2009-10-18 11:26:01.000000000 +0200
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef __AUFS_TYPE_H__
+#define __AUFS_TYPE_H__
+
+#include <linux/ioctl.h>
+
+#define AUFS_VERSION	"2-standalone.tree-30-20090803"
+
+/* todo? move this to linux-2.6.19/include/magic.h */
+#define AUFS_SUPER_MAGIC	('a' << 24 | 'u' << 16 | 'f' << 8 | 's')
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_BRANCH_MAX_127
+/* some environments treat 'char' as 'unsigned char' by default */
+typedef signed char aufs_bindex_t;
+#define AUFS_BRANCH_MAX 127
+#else
+typedef short aufs_bindex_t;
+#ifdef CONFIG_AUFS_BRANCH_MAX_511
+#define AUFS_BRANCH_MAX 511
+#elif defined(CONFIG_AUFS_BRANCH_MAX_1023)
+#define AUFS_BRANCH_MAX 1023
+#elif defined(CONFIG_AUFS_BRANCH_MAX_32767)
+#define AUFS_BRANCH_MAX 32767
+#endif
+#endif
+
+#ifdef __KERNEL__
+#ifndef AUFS_BRANCH_MAX
+#error unknown CONFIG_AUFS_BRANCH_MAX value
+#endif
+#endif /* __KERNEL__ */
+
+/* ---------------------------------------------------------------------- */
+
+#define AUFS_NAME		"aufs"
+#define AUFS_FSTYPE		AUFS_NAME
+
+#define AUFS_ROOT_INO		2
+#define AUFS_FIRST_INO		11
+
+#define AUFS_WH_PFX		".wh."
+#define AUFS_WH_PFX_LEN		((int)sizeof(AUFS_WH_PFX) - 1)
+#define AUFS_XINO_FNAME		"." AUFS_NAME ".xino"
+#define AUFS_XINO_DEFPATH	"/tmp/" AUFS_XINO_FNAME
+#define AUFS_XINO_TRUNC_INIT	64 /* blocks */
+#define AUFS_XINO_TRUNC_STEP	4  /* blocks */
+#define AUFS_DIRWH_DEF		3
+#define AUFS_RDCACHE_DEF	10 /* seconds */
+#define AUFS_RDBLK_DEF		512 /* bytes */
+#define AUFS_RDHASH_DEF		32
+#define AUFS_WKQ_NAME		AUFS_NAME "d"
+#define AUFS_NWKQ_DEF		4
+#define AUFS_MFS_SECOND_DEF	30 /* seconds */
+#define AUFS_PLINK_WARN		100 /* number of plinks */
+
+#define AUFS_DIROPQ_NAME	AUFS_WH_PFX ".opq" /* whiteouted doubly */
+#define AUFS_WH_DIROPQ		AUFS_WH_PFX AUFS_DIROPQ_NAME
+
+#define AUFS_BASE_NAME		AUFS_WH_PFX AUFS_NAME
+#define AUFS_PLINKDIR_NAME	AUFS_WH_PFX "plnk"
+#define AUFS_ORPHDIR_NAME	AUFS_WH_PFX "orph"
+
+/* doubly whiteouted */
+#define AUFS_WH_BASE		AUFS_WH_PFX AUFS_BASE_NAME
+#define AUFS_WH_PLINKDIR	AUFS_WH_PFX AUFS_PLINKDIR_NAME
+#define AUFS_WH_ORPHDIR		AUFS_WH_PFX AUFS_ORPHDIR_NAME
+
+/* branch permission */
+#define AUFS_BRPERM_RW		"rw"
+#define AUFS_BRPERM_RO		"ro"
+#define AUFS_BRPERM_RR		"rr"
+#define AUFS_BRPERM_WH		"wh"
+#define AUFS_BRPERM_NLWH	"nolwh"
+#define AUFS_BRPERM_ROWH	AUFS_BRPERM_RO "+" AUFS_BRPERM_WH
+#define AUFS_BRPERM_RRWH	AUFS_BRPERM_RR "+" AUFS_BRPERM_WH
+#define AUFS_BRPERM_RWNLWH	AUFS_BRPERM_RW "+" AUFS_BRPERM_NLWH
+
+/* ---------------------------------------------------------------------- */
+
+/* ioctl */
+enum {
+	AuCtl_PLINK_MAINT,
+	AuCtl_PLINK_CLEAN
+};
+
+#define AuCtlType		'A'
+#define AUFS_CTL_PLINK_MAINT	_IO(AuCtlType, AuCtl_PLINK_MAINT)
+#define AUFS_CTL_PLINK_CLEAN	_IO(AuCtlType, AuCtl_PLINK_CLEAN)
+
+#endif /* __AUFS_TYPE_H__ */
diff -Nur linux-2.6.31.4.orig/include/linux/Kbuild linux-2.6.31.4/include/linux/Kbuild
--- linux-2.6.31.4.orig/include/linux/Kbuild	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/include/linux/Kbuild	2009-10-18 11:26:01.000000000 +0200
@@ -34,6 +34,7 @@
 header-y += atmsap.h
 header-y += atmsvc.h
 header-y += atm_zatm.h
+header-y += aufs_type.h
 header-y += auto_fs4.h
 header-y += ax25.h
 header-y += b1lli.h
diff -Nur linux-2.6.31.4.orig/include/linux/namei.h linux-2.6.31.4/include/linux/namei.h
--- linux-2.6.31.4.orig/include/linux/namei.h	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/include/linux/namei.h	2009-10-18 11:26:01.000000000 +0200
@@ -75,6 +75,9 @@
 extern struct file *nameidata_to_filp(struct nameidata *nd, int flags);
 extern void release_open_intent(struct nameidata *);
 
+extern struct dentry *lookup_hash(struct nameidata *nd);
+extern int __lookup_one_len(const char *name, struct qstr *this,
+			    struct dentry *base, int len);
 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
 extern struct dentry *lookup_one_noperm(const char *, struct dentry *);
 
diff -Nur linux-2.6.31.4.orig/include/linux/splice.h linux-2.6.31.4/include/linux/splice.h
--- linux-2.6.31.4.orig/include/linux/splice.h	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/include/linux/splice.h	2009-10-18 11:26:01.000000000 +0200
@@ -82,4 +82,10 @@
 extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
 				      splice_direct_actor *);
 
+extern long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
+			   loff_t *ppos, size_t len, unsigned int flags);
+extern long do_splice_to(struct file *in, loff_t *ppos,
+			 struct pipe_inode_info *pipe, size_t len,
+			 unsigned int flags);
+
 #endif
diff -Nur linux-2.6.31.4.orig/security/device_cgroup.c linux-2.6.31.4/security/device_cgroup.c
--- linux-2.6.31.4.orig/security/device_cgroup.c	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/security/device_cgroup.c	2009-10-18 11:26:01.000000000 +0200
@@ -513,6 +513,7 @@
 
 	return -EPERM;
 }
+EXPORT_SYMBOL(devcgroup_inode_permission);
 
 int devcgroup_inode_mknod(int mode, dev_t dev)
 {
diff -Nur linux-2.6.31.4.orig/security/security.c linux-2.6.31.4/security/security.c
--- linux-2.6.31.4.orig/security/security.c	2009-10-12 22:15:40.000000000 +0200
+++ linux-2.6.31.4/security/security.c	2009-10-18 11:26:01.000000000 +0200
@@ -386,6 +386,7 @@
 		return 0;
 	return security_ops->path_mkdir(path, dentry, mode);
 }
+EXPORT_SYMBOL(security_path_mkdir);
 
 int security_path_rmdir(struct path *path, struct dentry *dentry)
 {
@@ -393,6 +394,7 @@
 		return 0;
 	return security_ops->path_rmdir(path, dentry);
 }
+EXPORT_SYMBOL(security_path_rmdir);
 
 int security_path_unlink(struct path *path, struct dentry *dentry)
 {
@@ -400,6 +402,7 @@
 		return 0;
 	return security_ops->path_unlink(path, dentry);
 }
+EXPORT_SYMBOL(security_path_unlink);
 
 int security_path_symlink(struct path *path, struct dentry *dentry,
 			  const char *old_name)
@@ -408,6 +411,7 @@
 		return 0;
 	return security_ops->path_symlink(path, dentry, old_name);
 }
+EXPORT_SYMBOL(security_path_symlink);
 
 int security_path_link(struct dentry *old_dentry, struct path *new_dir,
 		       struct dentry *new_dentry)
@@ -416,6 +420,7 @@
 		return 0;
 	return security_ops->path_link(old_dentry, new_dir, new_dentry);
 }
+EXPORT_SYMBOL(security_path_link);
 
 int security_path_rename(struct path *old_dir, struct dentry *old_dentry,
 			 struct path *new_dir, struct dentry *new_dentry)
@@ -426,6 +431,7 @@
 	return security_ops->path_rename(old_dir, old_dentry, new_dir,
 					 new_dentry);
 }
+EXPORT_SYMBOL(security_path_rename);
 
 int security_path_truncate(struct path *path, loff_t length,
 			   unsigned int time_attrs)
@@ -434,6 +440,7 @@
 		return 0;
 	return security_ops->path_truncate(path, length, time_attrs);
 }
+EXPORT_SYMBOL(security_path_truncate);
 #endif
 
 int security_inode_create(struct inode *dir, struct dentry *dentry, int mode)
@@ -505,6 +512,7 @@
 		return 0;
 	return security_ops->inode_readlink(dentry);
 }
+EXPORT_SYMBOL(security_inode_readlink);
 
 int security_inode_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
@@ -519,6 +527,7 @@
 		return 0;
 	return security_ops->inode_permission(inode, mask);
 }
+EXPORT_SYMBOL(security_inode_permission);
 
 int security_inode_setattr(struct dentry *dentry, struct iattr *attr)
 {
@@ -619,6 +628,7 @@
 {
 	return security_ops->file_permission(file, mask);
 }
+EXPORT_SYMBOL(security_file_permission);
 
 int security_file_alloc(struct file *file)
 {