Exemplo n.º 1
0
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++;
	}

	/* d_count can be zero */
	dpage->dentries[dpage->ndentry++] = dget_locked(dentry);
	return 0; /* success */

out:
	return err;
}
Exemplo n.º 2
0
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);

	err = aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH | AuLock_GEN);
	if (unlikely(err))
		goto out;
	err = au_alive_dir(dentry);
	if (unlikely(err))
		goto out_unlock;
	inode = dentry->d_inode;
	IMustLock(inode);
	err = -ENOTDIR;
	if (unlikely(!S_ISDIR(inode->i_mode)))
		goto out_unlock; /* possible? */

	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_parent;

	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_parent;

	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_hn_free(au_hi(inode, bstart));

		/* dir inode is locked */
		IMustLock(wh_dentry->d_parent->d_inode);
		err = 0;
	}

	if (!err) {
		vfsub_dead_dir(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, bindex, bwh, wh_dentry, dentry, &dt);
		if (rerr)
			err = rerr;
	}

out_unpin:
	au_unpin(&pin);
	dput(wh_dentry);
	dput(h_dentry);
out_parent:
	di_write_unlock(parent);
	if (args)
		au_whtmp_rmdir_free(args);
out_unlock:
	aufs_read_unlock(dentry, AuLock_DW);
out:
	AuTraceErr(err);
	return err;
}
Exemplo n.º 3
0
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_dio:
			AuLabel(dio);
			break;
		case Opt_nodio:
			AuLabel(nodio);
			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
}
Exemplo n.º 4
0
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;
}
Exemplo n.º 5
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;

	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;
	parent = dget_parent(dentry);
	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_parent;
		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)) {
		err = -EIO;
		AuIOErr("both of real entry and whiteout found, %.*s, err %d\n",
			AuDLNPair(dentry), err);
	}

out_parent:
	dput(parent);
	kfree(whname.name);
out:
	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;

	parent = dget_parent(dentry);
	h_parent = au_h_dptr(parent, bindex);
	h_dentry = au_sio_lkup_one(&dentry->d_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("%.*s should be negative on b%d.\n",
			AuDLNPair(h_dentry), bindex);
		dput(h_dentry);
		goto out;
	}

	err = 0;
	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);

out:
	dput(parent);
	return err;
}
Exemplo n.º 6
0
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;

	err = aufs_read_lock(dentry, AuLock_DW | AuLock_GEN);
	if (unlikely(err))
		goto out_free;
	err = au_d_may_add(dentry);
	if (unlikely(err))
		goto out_unlock;

	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_parent;

	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_unpin;

	/* 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_unpin; /* 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;
	}
	au_dtime_revert(&a->dt);
out_unpin:
	au_unpin(&a->pin);
	dput(wh_dentry);
out_parent:
	di_write_unlock(parent);
out_unlock:
	if (unlikely(err)) {
		au_update_dbstart(dentry);
		d_drop(dentry);
	}
	aufs_read_unlock(dentry, AuLock_DW);
out_free:
	kfree(a);
out:
	return err;
}
Exemplo n.º 7
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)
{
	int npositive, err;
	aufs_bindex_t bindex, btail, bdiropq;
	unsigned char isdir, dirperm1;
	struct qstr whname;
	struct au_do_lookup_args args = {
		.flags		= 0,
		.type		= type
	};
	const struct qstr *name = &dentry->d_name;
	struct dentry *parent;
	struct super_block *sb;

	sb = dentry->d_sb;
	err = au_test_shwh(sb, name);
	if (unlikely(err))
		goto out;

	err = au_wh_name_alloc(&whname, name);
	if (unlikely(err))
		goto out;

	isdir = !!d_is_dir(dentry);
	if (!type)
		au_fset_lkup(args.flags, ALLOW_NEG);
	dirperm1 = !!au_opt_test(au_mntflags(sb), DIRPERM1);

	npositive = 0;
	parent = dget_parent(dentry);
	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 (d_is_positive(h_dentry))
				npositive++;
			if (type != S_IFDIR)
				break;
			continue;
		}
		h_parent = au_h_dptr(parent, bindex);
		if (!h_parent || !d_is_dir(h_parent))
			continue;

		h_dir = d_inode(h_parent);
		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_parent;
		if (h_dentry)
			au_fclr_lkup(args.flags, ALLOW_NEG);
		if (dirperm1)
			au_fset_lkup(args.flags, IGNORE_PERM);

		if (au_dbwh(dentry) >= 0)
			break;
		if (!h_dentry)
			continue;
		if (d_is_negative(h_dentry))
			continue;
		h_inode = d_inode(h_dentry);
		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(sb), UDBA_NONE)
		     && au_dbstart(dentry) < 0)) {
		err = -EIO;
		AuIOErr("both of real entry and whiteout found, %pd, err %d\n",
			dentry, err);
	}

out_parent:
	dput(parent);
	kfree(whname.name);
out:
	return err;
}

struct dentry *au_sio_lkup_one(struct qstr *name, struct dentry *parent)
{
	struct dentry *dentry;
	int wkq_err;

	if (!au_test_h_perm_sio(d_inode(parent), MAY_EXEC))
		dentry = vfsub_lkup_one(name, parent);
	else {
		struct vfsub_lkup_one_args args = {
			.errp	= &dentry,
			.name	= name,
			.parent	= parent
		};

		wkq_err = au_wkq_wait(vfsub_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 wh)
{
	int err;
	struct dentry *parent, *h_parent, *h_dentry;
	struct au_branch *br;

	parent = dget_parent(dentry);
	h_parent = au_h_dptr(parent, bindex);
	br = au_sbr(dentry->d_sb, bindex);
	if (wh)
		h_dentry = au_whtmp_lkup(h_parent, br, &dentry->d_name);
	else
		h_dentry = au_sio_lkup_one(&dentry->d_name, h_parent);
	err = PTR_ERR(h_dentry);
	if (IS_ERR(h_dentry))
		goto out;
	if (unlikely(d_is_positive(h_dentry))) {
		err = -EIO;
		AuIOErr("%pd should be negative on b%d.\n", h_dentry, bindex);
		dput(h_dentry);
		goto out;
	}

	err = 0;
	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);

out:
	dput(parent);
	return err;
}