1 files changed, 830 insertions, 0 deletions

diff --git a/fs/aufs/wbr_policy.c b/fs/aufs/wbr_policy.c
new file mode 100644
index 000000000000..a7cc1109f69d
--- /dev/null
+++ b/fs/aufs/wbr_policy.c
@@ -0,0 +1,830 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2005-2020 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, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * 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 = d_inode(h_src);
+	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(d_inode(h_path->dentry), h_isrc->i_flags);
+	/* no delegation since it is just created */
+	err = vfsub_sio_notify_change(h_path, &ia, /*delegated*/NULL);
+
+	/* 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, /*delegated*/NULL);
+	}
+
+	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) \
+	do { (flags) |= AuCpdown_##name; } while (0)
+#define au_fclr_cpdown(flags, name) \
+	do { (flags) &= ~AuCpdown_##name; } while (0)
+
+static int au_cpdown_dir_opq(struct dentry *dentry, aufs_bindex_t bdst,
+			     unsigned int *flags)
+{
+	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(*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 (d_is_positive(h_path.dentry)) {
+		h_path.mnt = au_br_mnt(br);
+		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 au_pin *pin,
+			 struct dentry *h_parent, void *arg)
+{
+	int err, rerr;
+	aufs_bindex_t bopq, btop;
+	struct path h_path;
+	struct dentry *parent;
+	struct inode *h_dir, *h_inode, *inode, *dir;
+	unsigned int *flags = arg;
+
+	btop = au_dbtop(dentry);
+	/* dentry is di-locked */
+	parent = dget_parent(dentry);
+	dir = d_inode(parent);
+	h_dir = d_inode(h_parent);
+	AuDebugOn(h_dir != au_h_iptr(dir, bdst));
+	IMustLock(h_dir);
+
+	err = au_lkup_neg(dentry, bdst, /*wh*/0);
+	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, 0755);
+	if (unlikely(err))
+		goto out_put;
+	au_fset_cpdown(*flags, MADE_DIR);
+
+	bopq = au_dbdiropq(dentry);
+	au_fclr_cpdown(*flags, WHED);
+	au_fclr_cpdown(*flags, DIROPQ);
+	if (au_dbwh(dentry) == bdst)
+		au_fset_cpdown(*flags, WHED);
+	if (!au_ftest_cpdown(*flags, PARENT_OPQ) && bopq <= bdst)
+		au_fset_cpdown(*flags, PARENT_OPQ);
+	h_inode = d_inode(h_path.dentry);
+	inode_lock_nested(h_inode, AuLsc_I_CHILD);
+	if (au_ftest_cpdown(*flags, WHED)) {
+		err = au_cpdown_dir_opq(dentry, bdst, flags);
+		if (unlikely(err)) {
+			inode_unlock(h_inode);
+			goto out_dir;
+		}
+	}
+
+	err = au_cpdown_attr(&h_path, au_h_dptr(dentry, btop));
+	inode_unlock(h_inode);
+	if (unlikely(err))
+		goto out_opq;
+
+	if (au_ftest_cpdown(*flags, WHED)) {
+		err = au_cpdown_dir_wh(dentry, h_parent, dir, bdst);
+		if (unlikely(err))
+			goto out_opq;
+	}
+
+	inode = d_inode(dentry);
+	if (au_ibbot(inode) < bdst)
+		au_set_ibbot(inode, bdst);
+	au_set_h_iptr(inode, bdst, au_igrab(h_inode),
+		      au_hi_flags(inode, /*isdir*/1));
+	au_fhsm_wrote(dentry->d_sb, bdst, /*force*/0);
+	goto out; /* success */
+
+	/* revert */
+out_opq:
+	if (au_ftest_cpdown(*flags, DIROPQ)) {
+		inode_lock_nested(h_inode, AuLsc_I_CHILD);
+		rerr = au_diropq_remove(dentry, bdst);
+		inode_unlock(h_inode);
+		if (unlikely(rerr)) {
+			AuIOErr("failed removing diropq for %pd b%d (%d)\n",
+				dentry, bdst, rerr);
+			err = -EIO;
+			goto out;
+		}
+	}
+out_dir:
+	if (au_ftest_cpdown(*flags, MADE_DIR)) {
+		rerr = vfsub_sio_rmdir(au_h_iptr(dir, bdst), &h_path);
+		if (unlikely(rerr)) {
+			AuIOErr("failed removing %pd b%d (%d)\n",
+				dentry, bdst, rerr);
+			err = -EIO;
+		}
+	}
+out_put:
+	au_set_h_dptr(dentry, bdst, NULL);
+	if (au_dbbot(dentry) == bdst)
+		au_update_dbbot(dentry);
+out:
+	dput(parent);
+	return err;
+}
+
+int au_cpdown_dirs(struct dentry *dentry, aufs_bindex_t bdst)
+{
+	int err;
+	unsigned int flags;
+
+	flags = 0;
+	err = au_cp_dirs(dentry, bdst, au_cpdown_dir, &flags);
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* policies for create */
+
+int au_wbr_nonopq(struct dentry *dentry, aufs_bindex_t bindex)
+{
+	int err, i, j, ndentry;
+	aufs_bindex_t bopq;
+	struct au_dcsub_pages dpages;
+	struct au_dpage *dpage;
+	struct dentry **dentries, *parent, *d;
+
+	err = au_dpages_init(&dpages, GFP_NOFS);
+	if (unlikely(err))
+		goto out;
+	parent = dget_parent(dentry);
+	err = au_dcsub_pages_rev_aufs(&dpages, parent, /*do_include*/0);
+	if (unlikely(err))
+		goto out_free;
+
+	err = bindex;
+	for (i = 0; i < dpages.ndpage; i++) {
+		dpage = dpages.dpages + i;
+		dentries = dpage->dentries;
+		ndentry = dpage->ndentry;
+		for (j = 0; j < ndentry; j++) {
+			d = dentries[j];
+			di_read_lock_parent2(d, !AuLock_IR);
+			bopq = au_dbdiropq(d);
+			di_read_unlock(d, !AuLock_IR);
+			if (bopq >= 0 && bopq < err)
+				err = bopq;
+		}
+	}
+
+out_free:
+	dput(parent);
+	au_dpages_free(&dpages);
+out:
+	return err;
+}
+
+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,
+			     unsigned int flags __maybe_unused)
+{
+	int err;
+	aufs_bindex_t btop, bindex;
+	struct super_block *sb;
+	struct dentry *parent, *h_parent;
+
+	sb = dentry->d_sb;
+	btop = au_dbtop(dentry);
+	err = btop;
+	if (!au_br_rdonly(au_sbr(sb, btop)))
+		goto out;
+
+	err = -EROFS;
+	parent = dget_parent(dentry);
+	for (bindex = au_dbtop(parent); bindex < btop; bindex++) {
+		h_parent = au_h_dptr(parent, bindex);
+		if (!h_parent || d_is_negative(h_parent))
+			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, btop - 1);
+		if (err >= 0)
+			err = au_wbr_nonopq(dentry, err);
+	}
+
+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)
+		err = au_wbr_nonopq(dentry, err);
+
+	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_sbbot(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, unsigned int flags)
+{
+	int err, nbr;
+	unsigned int u;
+	aufs_bindex_t bindex, bbot;
+	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;
+	bbot = au_sbbot(sb);
+	nbr = bbot + 1;
+	for (bindex = 0; bindex <= bbot; bindex++) {
+		if (!au_ftest_wbr(flags, DIR)) {
+			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;
+	}
+
+	if (err >= 0)
+		err = au_wbr_nonopq(dentry, err);
+
+out:
+	AuDbg("%d\n", err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* most free space */
+static void au_mfs(struct dentry *dentry, struct dentry *parent)
+{
+	struct super_block *sb;
+	struct au_branch *br;
+	struct au_wbr_mfs *mfs;
+	struct dentry *h_parent;
+	aufs_bindex_t bindex, bbot;
+	int err;
+	unsigned long long b, bavail;
+	struct path h_path;
+	/* 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;
+	if (!parent) {
+		bindex = 0;
+		bbot = au_sbbot(sb);
+	} else {
+		bindex = au_dbtop(parent);
+		bbot = au_dbtaildir(parent);
+	}
+
+	for (; bindex <= bbot; bindex++) {
+		if (parent) {
+			h_parent = au_h_dptr(parent, bindex);
+			if (!h_parent || d_is_negative(h_parent))
+				continue;
+		}
+		br = au_sbr(sb, bindex);
+		if (au_br_rdonly(br))
+			continue;
+
+		/* sb->s_root for NFS is unreliable */
+		h_path.mnt = au_br_mnt(br);
+		h_path.dentry = h_path.mnt->mnt_root;
+		err = vfs_statfs(&h_path, 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);
+	au_kfree_rcu(st);
+}
+
+static int au_wbr_create_mfs(struct dentry *dentry, unsigned int flags)
+{
+	int err;
+	struct dentry *parent;
+	struct super_block *sb;
+	struct au_wbr_mfs *mfs;
+
+	err = au_wbr_create_exp(dentry);
+	if (err >= 0)
+		goto out;
+
+	sb = dentry->d_sb;
+	parent = NULL;
+	if (au_ftest_wbr(flags, PARENT))
+		parent = dget_parent(dentry);
+	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, parent);
+	mutex_unlock(&mfs->mfs_lock);
+	err = mfs->mfs_bindex;
+	dput(parent);
+
+	if (err >= 0)
+		err = au_wbr_nonopq(dentry, err);
+
+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;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* top down regardless parent, and then mfs */
+static int au_wbr_create_tdmfs(struct dentry *dentry,
+			       unsigned int flags __maybe_unused)
+{
+	int err;
+	aufs_bindex_t bwh, btail, bindex, bfound, bmfs;
+	unsigned long long watermark;
+	struct super_block *sb;
+	struct au_wbr_mfs *mfs;
+	struct au_branch *br;
+	struct dentry *parent;
+
+	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_mfs(dentry, /*parent*/NULL);
+	watermark = mfs->mfsrr_watermark;
+	bmfs = mfs->mfs_bindex;
+	mutex_unlock(&mfs->mfs_lock);
+
+	/* another style of au_wbr_create_exp() */
+	bwh = au_dbwh(dentry);
+	parent = dget_parent(dentry);
+	btail = au_dbtaildir(parent);
+	if (bwh >= 0 && bwh < btail)
+		btail = bwh;
+
+	err = au_wbr_nonopq(dentry, btail);
+	if (unlikely(err < 0))
+		goto out;
+	btail = err;
+	bfound = -1;
+	for (bindex = 0; bindex <= btail; bindex++) {
+		br = au_sbr(sb, bindex);
+		if (au_br_rdonly(br))
+			continue;
+		if (br->br_wbr->wbr_bytes > watermark) {
+			bfound = bindex;
+			break;
+		}
+	}
+	err = bfound;
+	if (err < 0)
+		err = bmfs;
+
+out:
+	dput(parent);
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* most free space and then round robin */
+static int au_wbr_create_mfsrr(struct dentry *dentry, unsigned int flags)
+{
+	int err;
+	struct au_wbr_mfs *mfs;
+
+	err = au_wbr_create_mfs(dentry, flags);
+	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, flags);
+		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, unsigned int flags)
+{
+	int err, e2;
+	unsigned long long b;
+	aufs_bindex_t bindex, btop, bbot;
+	struct super_block *sb;
+	struct dentry *parent, *h_parent;
+	struct au_branch *br;
+
+	err = au_wbr_create_tdp(dentry, flags);
+	if (unlikely(err < 0))
+		goto out;
+	parent = dget_parent(dentry);
+	btop = au_dbtop(parent);
+	bbot = au_dbtaildir(parent);
+	if (btop == bbot)
+		goto out_parent; /* success */
+
+	e2 = au_wbr_create_mfs(dentry, flags);
+	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 = btop; bindex <= bbot; bindex++) {
+		h_parent = au_h_dptr(parent, bindex);
+		if (!h_parent || d_is_negative(h_parent))
+			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);
+		}
+	}
+
+	if (err >= 0)
+		err = au_wbr_nonopq(dentry, err);
+
+out_parent:
+	dput(parent);
+out:
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * - top down parent
+ * - most free space with parent
+ * - most free space round-robin regardless parent
+ */
+static int au_wbr_create_pmfsrr(struct dentry *dentry, unsigned int flags)
+{
+	int err;
+	unsigned long long watermark;
+	struct super_block *sb;
+	struct au_branch *br;
+	struct au_wbr_mfs *mfs;
+
+	err = au_wbr_create_pmfs(dentry, flags | AuWbr_PARENT);
+	if (unlikely(err < 0))
+		goto out;
+
+	sb = dentry->d_sb;
+	br = au_sbr(sb, err);
+	mfs = &au_sbi(sb)->si_wbr_mfs;
+	mutex_lock(&mfs->mfs_lock);
+	watermark = mfs->mfsrr_watermark;
+	mutex_unlock(&mfs->mfs_lock);
+	if (br->br_wbr->wbr_bytes < watermark)
+		/* regardless the parent dir */
+		err = au_wbr_create_mfsrr(dentry, flags);
+
+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, /*flags, anything is ok*/0);
+}
+
+/* bottom up parent */
+static int au_wbr_copyup_bup(struct dentry *dentry)
+{
+	int err;
+	aufs_bindex_t bindex, btop;
+	struct dentry *parent, *h_parent;
+	struct super_block *sb;
+
+	err = -EROFS;
+	sb = dentry->d_sb;
+	parent = dget_parent(dentry);
+	btop = au_dbtop(parent);
+	for (bindex = au_dbtop(dentry); bindex >= btop; bindex--) {
+		h_parent = au_h_dptr(parent, bindex);
+		if (!h_parent || d_is_negative(h_parent))
+			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, btop - 1);
+
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+/* bottom up */
+int au_wbr_do_copyup_bu(struct dentry *dentry, aufs_bindex_t btop)
+{
+	int err;
+
+	err = au_wbr_bu(dentry->d_sb, btop);
+	AuDbg("b%d\n", err);
+	if (err > btop)
+		err = au_wbr_nonopq(dentry, err);
+
+	AuDbg("b%d\n", err);
+	return err;
+}
+
+static int au_wbr_copyup_bu(struct dentry *dentry)
+{
+	int err;
+	aufs_bindex_t btop;
+
+	btop = au_dbtop(dentry);
+	err = au_wbr_do_copyup_bu(dentry, btop);
+	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_TDMFS] = {
+		.create	= au_wbr_create_tdmfs,
+		.init	= au_wbr_create_init_mfs,
+		.fin	= au_wbr_create_fin_mfs
+	},
+	[AuWbrCreate_TDMFSV] = {
+		.create	= au_wbr_create_tdmfs,
+		.init	= au_wbr_create_init_mfs,
+		.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
+	},
+	[AuWbrCreate_PMFSRR] = {
+		.create	= au_wbr_create_pmfsrr,
+		.init	= au_wbr_create_init_mfsrr,
+		.fin	= au_wbr_create_fin_mfs
+	},
+	[AuWbrCreate_PMFSRRV] = {
+		.create	= au_wbr_create_pmfsrr,
+		.init	= au_wbr_create_init_mfsrr,
+		.fin	= au_wbr_create_fin_mfs
+	}
+};