Linux-libre 4.2.1-gnupck-4.2.1-gnu

1 files changed, 1063 insertions, 0 deletions

diff --git a/fs/aufs/whout.c b/fs/aufs/whout.c
new file mode 100644
index 000000000..c3fc2d4bd
--- /dev/null
+++ b/fs/aufs/whout.c
@@ -0,0 +1,1063 @@
+/*
+ * Copyright (C) 2005-2015 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/>.
+ */
+
+/*
+ * whiteout for logical deletion and opaque directory
+ */
+
+#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 = QSTR_INIT(AUFS_WH_DIROPQ,
+					   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, int try_sio)
+{
+	int err;
+	struct dentry *wh_dentry;
+
+	if (!try_sio)
+		wh_dentry = vfsub_lkup_one(wh_name, h_parent);
+	else
+		wh_dentry = au_sio_lkup_one(wh_name, h_parent);
+	err = PTR_ERR(wh_dentry);
+	if (IS_ERR(wh_dentry)) {
+		if (err == -ENAMETOOLONG)
+			err = 0;
+		goto out;
+	}
+
+	err = 0;
+	if (d_is_negative(wh_dentry))
+		goto out_wh; /* success */
+
+	err = 1;
+	if (d_is_reg(wh_dentry))
+		goto out_wh; /* success */
+
+	err = -EIO;
+	AuIOErr("%pd Invalid whiteout entry type 0%o.\n",
+		wh_dentry, d_inode(wh_dentry)->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)
+{
+	int err;
+	struct inode *h_dir;
+
+	h_dir = d_inode(h_dentry);
+	err = au_wh_test(h_dentry, &diropq_name,
+			 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)
+{
+	struct dentry *dentry;
+	int i;
+	char defname[NAME_MAX - AUFS_MAX_NAMELEN + DNAME_INLINE_LEN + 1],
+		*name, *p;
+	/* strict atomic_t is unnecessary here */
+	static unsigned short cnt;
+	struct qstr qs;
+
+	BUILD_BUG_ON(sizeof(cnt) * 2 > AUFS_WH_TMP_LEN);
+
+	name = defname;
+	qs.len = sizeof(defname) - DNAME_INLINE_LEN + prefix->len - 1;
+	if (unlikely(prefix->len > DNAME_INLINE_LEN)) {
+		dentry = ERR_PTR(-ENAMETOOLONG);
+		if (unlikely(qs.len > NAME_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 <= AUFS_WH_TMP_LEN);
+
+	qs.name = name;
+	for (i = 0; i < 3; i++) {
+		sprintf(p, "%.*x", AUFS_WH_TMP_LEN, cnt++);
+		dentry = au_sio_lkup_one(&qs, h_parent);
+		if (IS_ERR(dentry) || d_is_negative(dentry))
+			goto out_name;
+		dput(dentry);
+	}
+	/* pr_warn("could not get random name\n"); */
+	dentry = ERR_PTR(-EEXIST);
+	AuDbg("%.*s\n", AuLNPair(&qs));
+	BUG();
+
+out_name:
+	if (name != defname)
+		kfree(name);
+out:
+	AuTraceErrPtr(dentry);
+	return dentry;
+}
+
+/*
+ * 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 = au_br_mnt(br)
+	};
+	struct inode *h_dir, *delegated;
+	struct dentry *h_parent;
+
+	h_parent = h_dentry->d_parent; /* dir inode is locked */
+	h_dir = d_inode(h_parent);
+	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() */
+	delegated = NULL;
+	err = vfsub_rename(h_dir, h_dentry, h_dir, &h_path, &delegated);
+	AuTraceErr(err);
+	if (unlikely(err == -EWOULDBLOCK)) {
+		pr_warn("cannot retry for NFSv4 delegation"
+			" for an internal rename\n");
+		iput(delegated);
+	}
+	dput(h_path.dentry);
+
+out:
+	AuTraceErr(err);
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+/*
+ * functions for removing a whiteout
+ */
+
+static int do_unlink_wh(struct inode *h_dir, struct path *h_path)
+{
+	int err, force;
+	struct inode *delegated;
+
+	/*
+	 * 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)
+		&& !uid_eq(current_fsuid(), d_inode(h_path->dentry)->i_uid);
+	delegated = NULL;
+	err = vfsub_unlink(h_dir, h_path, &delegated, force);
+	if (unlikely(err == -EWOULDBLOCK)) {
+		pr_warn("cannot retry for NFSv4 delegation"
+			" for an internal unlink\n");
+		iput(delegated);
+	}
+	return err;
+}
+
+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 = au_br_mnt(br)
+	};
+
+	err = 0;
+	h_path.dentry = vfsub_lkup_one(wh, h_parent);
+	if (IS_ERR(h_path.dentry))
+		err = PTR_ERR(h_path.dentry);
+	else {
+		if (d_is_reg(h_path.dentry))
+			err = do_unlink_wh(d_inode(h_parent), &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;
+	struct inode *delegated;
+
+	if (d_is_negative(whpath->dentry))
+		return;
+
+	if (isdir)
+		err = vfsub_rmdir(h_dir, whpath);
+	else {
+		delegated = NULL;
+		err = vfsub_unlink(h_dir, whpath, &delegated, /*force*/0);
+		if (unlikely(err == -EWOULDBLOCK)) {
+			pr_warn("cannot retry for NFSv4 delegation"
+				" for an internal unlink\n");
+			iput(delegated);
+		}
+	}
+	if (unlikely(err))
+		pr_warn("failed removing %pd (%d), ignored.\n",
+			whpath->dentry, err);
+}
+
+static int test_linkable(struct dentry *h_root)
+{
+	struct inode *h_dir = d_inode(h_root);
+
+	if (h_dir->i_op->link)
+		return 0;
+
+	pr_err("%pd (%s) doesn't support link(2), use noplink and rw+nolwh\n",
+	       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 (d_is_negative(path->dentry)) {
+		int mode = S_IRWXU;
+
+		if (au_test_nfs(path->dentry->d_sb))
+			mode |= S_IXUGO;
+		err = vfsub_mkdir(h_dir, path, mode);
+	} else if (d_is_dir(path->dentry))
+		err = 0;
+	else
+		pr_err("unknown %pd exists\n", 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 message
+ * zero: succuess
+ * plus: error, caller should NOT print the message
+ */
+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 = d_inode(h_root);
+	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 = d_inode(h_root);
+	if (d_is_negative(base[AuBrWh_BASE].dentry)) {
+		h_path->dentry = base[AuBrWh_BASE].dentry;
+		err = vfsub_create(h_dir, h_path, WH_MASK, /*want_excl*/true);
+	} else if (d_is_reg(base[AuBrWh_BASE].dentry))
+		err = 0;
+	else
+		pr_err("unknown %pd2 exists\n", 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 au_branch *br, struct super_block *sb)
+{
+	int err, i;
+	const unsigned char do_plink
+		= !!au_opt_test(au_mntflags(sb), PLINK);
+	struct inode *h_dir;
+	struct path path = br->br_path;
+	struct dentry *h_root = path.dentry;
+	struct au_wbr *wbr = br->br_wbr;
+	static const struct qstr base_name[] = {
+		[AuBrWh_BASE] = QSTR_INIT(AUFS_BASE_NAME,
+					  sizeof(AUFS_BASE_NAME) - 1),
+		[AuBrWh_PLINK] = QSTR_INIT(AUFS_PLINKDIR_NAME,
+					   sizeof(AUFS_PLINKDIR_NAME) - 1),
+		[AuBrWh_ORPH] = QSTR_INIT(AUFS_ORPHDIR_NAME,
+					  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);
+
+	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;
+	if (!au_br_writable(br->br_perm)) {
+		h_dir = d_inode(h_root);
+		au_wh_init_ro(h_dir, base, &path);
+	} else if (!au_br_wh_linkable(br->br_perm)) {
+		err = au_wh_init_rw_nolink(h_root, wbr, do_plink, base, &path);
+		if (err > 0)
+			goto out;
+		else if (err)
+			goto out_err;
+	} else {
+		err = au_wh_init_rw(h_root, wbr, do_plink, base, &path);
+		if (err > 0)
+			goto out;
+		else if (err)
+			goto out_err;
+	}
+	goto out; /* success */
+
+out_err:
+	pr_err("an error(%d) on the writable branch %pd(%s)\n",
+	       err, 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, *delegated;
+	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 = d_inode(a->sb->s_root);
+	hdir = au_hi(dir, bindex);
+	h_root = au_h_dptr(a->sb->s_root, bindex);
+	AuDebugOn(h_root != au_br_dentry(a->br));
+
+	au_hn_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) {
+		h_path.dentry = wbr->wbr_whbase;
+		h_path.mnt = au_br_mnt(a->br);
+		delegated = NULL;
+		err = vfsub_unlink(hdir->hi_inode, &h_path, &delegated,
+				   /*force*/0);
+		if (unlikely(err == -EWOULDBLOCK)) {
+			pr_warn("cannot retry for NFSv4 delegation"
+				" for an internal unlink\n");
+			iput(delegated);
+		}
+	} else {
+		pr_warn("%pd is moved, ignored\n", wbr->wbr_whbase);
+		err = 0;
+	}
+	dput(wbr->wbr_whbase);
+	wbr->wbr_whbase = NULL;
+	if (!err)
+		err = au_wh_init(a->br, a->sb);
+	wbr_wh_write_unlock(wbr);
+	au_hn_imtx_unlock(hdir);
+	di_read_unlock(a->sb->s_root, AuLock_IR);
+	if (!err)
+		au_fhsm_wrote(a->sb, bindex, /*force*/0);
+
+out:
+	if (wbr)
+		atomic_dec(&wbr->wbr_wh_running);
+	atomic_dec(&a->br->br_count);
+	si_write_unlock(a->sb);
+	au_nwt_done(&au_sbi(a->sb)->si_nowait);
+	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, /*flags*/0);
+		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, *delegated;
+
+	h_parent = wh->d_parent; /* dir inode is locked */
+	h_dir = d_inode(h_parent);
+	IMustLock(h_dir);
+
+	br = au_sbr(sb, bindex);
+	h_path.mnt = au_br_mnt(br);
+	wbr = br->br_wbr;
+	wbr_wh_read_lock(wbr);
+	if (wbr->wbr_whbase) {
+		delegated = NULL;
+		err = vfsub_link(wbr->wbr_whbase, h_dir, &h_path, &delegated);
+		if (unlikely(err == -EWOULDBLOCK)) {
+			pr_warn("cannot retry for NFSv4 delegation"
+				" for an internal link\n");
+			iput(delegated);
+		}
+		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, /*want_excl*/true);
+	if (!err)
+		au_fhsm_wrote(sb, bindex, /*force*/0);
+
+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 = vfsub_lkup_one(&diropq_name, h_dentry);
+	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	= au_br_mnt(br)
+		};
+		err = do_unlink_wh(au_h_iptr(d_inode(dentry), 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(d_inode(h_dentry), 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 = vfsub_lkup_one(&wh_name, h_parent);
+		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) && d_is_negative(wh_dentry)) {
+		err = link_or_create_wh(sb, bindex, wh_dentry);
+		if (!err) {
+			au_set_dbwh(dentry, bindex);
+			au_fhsm_wrote(sb, bindex, /*force*/0);
+		} 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 *pos;
+	struct au_vdir_destr *str;
+
+	err = -ENOMEM;
+	p = (void *)__get_free_page(GFP_NOFS);
+	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(pos, head, wh_hash) {
+			if (pos->wh_bindex != bindex)
+				continue;
+
+			str = &pos->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;
+		}
+	}
+	free_page((unsigned long)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;
+	unsigned int rdhash;
+
+	SiMustAnyLock(sb);
+
+	whtmp = kmalloc(sizeof(*whtmp), gfp);
+	if (unlikely(!whtmp)) {
+		whtmp = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	whtmp->dir = NULL;
+	whtmp->br = NULL;
+	whtmp->wh_dentry = NULL;
+	/* no estimation for dir size */
+	rdhash = au_sbi(sb)->si_rdhash;
+	if (!rdhash)
+		rdhash = AUFS_RDHASH_DEF;
+	err = au_nhash_alloc(&whtmp->whlist, rdhash, gfp);
+	if (unlikely(err)) {
+		kfree(whtmp);
+		whtmp = ERR_PTR(err);
+	}
+
+out:
+	return whtmp;
+}
+
+void au_whtmp_rmdir_free(struct au_whtmp_rmdir *whtmp)
+{
+	if (whtmp->br)
+		atomic_dec(&whtmp->br->br_count);
+	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;
+	unsigned int h_nlink;
+	struct path h_tmp;
+	struct inode *wh_inode, *h_dir;
+	struct au_branch *br;
+
+	h_dir = d_inode(wh_dentry->d_parent); /* dir inode is locked */
+	IMustLock(h_dir);
+
+	br = au_sbr(dir->i_sb, bindex);
+	wh_inode = d_inode(wh_dentry);
+	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 = au_br_mnt(br);
+		h_nlink = h_dir->i_nlink;
+		err = vfsub_rmdir(h_dir, &h_tmp);
+		/* some fs doesn't change the parent nlink in some cases */
+		h_nlink -= h_dir->i_nlink;
+	}
+
+	if (!err) {
+		if (au_ibstart(dir) == bindex) {
+			/* todo: dir->i_mutex is necessary */
+			au_cpup_attr_timesizes(dir);
+			if (h_nlink)
+				vfsub_drop_nlink(dir);
+		}
+		return 0; /* success */
+	}
+
+	pr_warn("failed removing %pd(%d), ignored\n", wh_dentry, err);
+	return err;
+}
+
+static void call_rmdir_whtmp(void *args)
+{
+	int err;
+	aufs_bindex_t bindex;
+	struct au_whtmp_rmdir *a = args;
+	struct super_block *sb;
+	struct dentry *h_parent;
+	struct inode *h_dir;
+	struct au_hinode *hdir;
+
+	/* rmdir by nfsd may cause deadlock with this i_mutex */
+	/* mutex_lock(&a->dir->i_mutex); */
+	err = -EROFS;
+	sb = a->dir->i_sb;
+	si_read_lock(sb, !AuLock_FLUSH);
+	if (!au_br_writable(a->br->br_perm))
+		goto out;
+	bindex = au_br_index(sb, a->br->br_id);
+	if (unlikely(bindex < 0))
+		goto out;
+
+	err = -EIO;
+	ii_write_lock_parent(a->dir);
+	h_parent = dget_parent(a->wh_dentry);
+	h_dir = d_inode(h_parent);
+	hdir = au_hi(a->dir, bindex);
+	err = vfsub_mnt_want_write(au_br_mnt(a->br));
+	if (unlikely(err))
+		goto out_mnt;
+	au_hn_imtx_lock_nested(hdir, AuLsc_I_PARENT);
+	err = au_h_verify(a->wh_dentry, au_opt_udba(sb), h_dir, h_parent,
+			  a->br);
+	if (!err)
+		err = au_whtmp_rmdir(a->dir, bindex, a->wh_dentry, &a->whlist);
+	au_hn_imtx_unlock(hdir);
+	vfsub_mnt_drop_write(au_br_mnt(a->br));
+
+out_mnt:
+	dput(h_parent);
+	ii_write_unlock(a->dir);
+out:
+	/* mutex_unlock(&a->dir->i_mutex); */
+	au_whtmp_rmdir_free(a);
+	si_read_unlock(sb);
+	au_nwt_done(&au_sbi(sb)->si_nowait);
+	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;
+	struct super_block *sb;
+
+	IMustLock(dir);
+
+	/* all post-process will be done in do_rmdir_whtmp(). */
+	sb = dir->i_sb;
+	args->dir = au_igrab(dir);
+	args->br = au_sbr(sb, bindex);
+	atomic_inc(&args->br->br_count);
+	args->wh_dentry = dget(wh_dentry);
+	wkq_err = au_wkq_nowait(call_rmdir_whtmp, args, sb, /*flags*/0);
+	if (unlikely(wkq_err)) {
+		pr_warn("rmdir error %pd (%d), ignored\n", wh_dentry, wkq_err);
+		au_whtmp_rmdir_free(args);
+	}
+}