[linux.git] / fs / overlayfs / copy_up.c

/*
 *
 * Copyright (C) 2011 Novell Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/splice.h>
#include <linux/xattr.h>
#include <linux/security.h>
#include <linux/uaccess.h>
#include <linux/sched.h>
#include <linux/namei.h>
#include "overlayfs.h"

#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)

int ovl_copy_xattr(struct dentry *old, struct dentry *new)
{
	ssize_t list_size, size, value_size = 0;
	char *buf, *name, *value = NULL;
	int uninitialized_var(error);

	if (!old->d_inode->i_op->getxattr ||
	    !new->d_inode->i_op->getxattr)
		return 0;

	list_size = vfs_listxattr(old, NULL, 0);
	if (list_size <= 0) {
		if (list_size == -EOPNOTSUPP)
			return 0;
		return list_size;
	}

	buf = kzalloc(list_size, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	list_size = vfs_listxattr(old, buf, list_size);
	if (list_size <= 0) {
		error = list_size;
		goto out;
	}

	for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {
retry:
		size = vfs_getxattr(old, name, value, value_size);
		if (size == -ERANGE)
			size = vfs_getxattr(old, name, NULL, 0);

		if (size < 0) {
			error = size;
			break;
		}

		if (size > value_size) {
			void *new;

			new = krealloc(value, size, GFP_KERNEL);
			if (!new) {
				error = -ENOMEM;
				break;
			}
			value = new;
			value_size = size;
			goto retry;
		}

		error = vfs_setxattr(new, name, value, size, 0);
		if (error)
			break;
	}
	kfree(value);
out:
	kfree(buf);
	return error;
}

static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
{
	struct file *old_file;
	struct file *new_file;
	loff_t old_pos = 0;
	loff_t new_pos = 0;
	int error = 0;

	if (len == 0)
		return 0;

	old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY);
	if (IS_ERR(old_file))
		return PTR_ERR(old_file);

	new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY);
	if (IS_ERR(new_file)) {
		error = PTR_ERR(new_file);
		goto out_fput;
	}

	/* FIXME: copy up sparse files efficiently */
	while (len) {
		size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
		long bytes;

		if (len < this_len)
			this_len = len;

		if (signal_pending_state(TASK_KILLABLE, current)) {
			error = -EINTR;
			break;
		}

		bytes = do_splice_direct(old_file, &old_pos,
					 new_file, &new_pos,
					 this_len, SPLICE_F_MOVE);
		if (bytes <= 0) {
			error = bytes;
			break;
		}
		WARN_ON(old_pos != new_pos);

		len -= bytes;
	}

	fput(new_file);
out_fput:
	fput(old_file);
	return error;
}

static char *ovl_read_symlink(struct dentry *realdentry)
{
	int res;
	char *buf;
	struct inode *inode = realdentry->d_inode;
	mm_segment_t old_fs;

	res = -EINVAL;
	if (!inode->i_op->readlink)
		goto err;

	res = -ENOMEM;
	buf = (char *) __get_free_page(GFP_KERNEL);
	if (!buf)
		goto err;

	old_fs = get_fs();
	set_fs(get_ds());
	/* The cast to a user pointer is valid due to the set_fs() */
	res = inode->i_op->readlink(realdentry,
				    (char __user *)buf, PAGE_SIZE - 1);
	set_fs(old_fs);
	if (res < 0) {
		free_page((unsigned long) buf);
		goto err;
	}
	buf[res] = '\0';

	return buf;

err:
	return ERR_PTR(res);
}

static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat)
{
	struct iattr attr = {
		.ia_valid =
		     ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET,
		.ia_atime = stat->atime,
		.ia_mtime = stat->mtime,
	};

	return notify_change(upperdentry, &attr, NULL);
}

int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
{
	int err = 0;

	if (!S_ISLNK(stat->mode)) {
		struct iattr attr = {
			.ia_valid = ATTR_MODE,
			.ia_mode = stat->mode,
		};
		err = notify_change(upperdentry, &attr, NULL);
	}
	if (!err) {
		struct iattr attr = {
			.ia_valid = ATTR_UID | ATTR_GID,
			.ia_uid = stat->uid,
			.ia_gid = stat->gid,
		};
		err = notify_change(upperdentry, &attr, NULL);
	}
	if (!err)
		ovl_set_timestamps(upperdentry, stat);

	return err;
}

static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
			      struct dentry *dentry, struct path *lowerpath,
			      struct kstat *stat, const char *link)
{
	struct inode *wdir = workdir->d_inode;
	struct inode *udir = upperdir->d_inode;
	struct dentry *newdentry = NULL;
	struct dentry *upper = NULL;
	umode_t mode = stat->mode;
	int err;

	newdentry = ovl_lookup_temp(workdir, dentry);
	err = PTR_ERR(newdentry);
	if (IS_ERR(newdentry))
		goto out;

	upper = lookup_one_len(dentry->d_name.name, upperdir,
			       dentry->d_name.len);
	err = PTR_ERR(upper);
	if (IS_ERR(upper))
		goto out1;

	/* Can't properly set mode on creation because of the umask */
	stat->mode &= S_IFMT;
	err = ovl_create_real(wdir, newdentry, stat, link, NULL, true);
	stat->mode = mode;
	if (err)
		goto out2;

	if (S_ISREG(stat->mode)) {
		struct path upperpath;
		ovl_path_upper(dentry, &upperpath);
		BUG_ON(upperpath.dentry != NULL);
		upperpath.dentry = newdentry;

		err = ovl_copy_up_data(lowerpath, &upperpath, stat->size);
		if (err)
			goto out_cleanup;
	}

	err = ovl_copy_xattr(lowerpath->dentry, newdentry);
	if (err)
		goto out_cleanup;

	inode_lock(newdentry->d_inode);
	err = ovl_set_attr(newdentry, stat);
	inode_unlock(newdentry->d_inode);
	if (err)
		goto out_cleanup;

	err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
	if (err)
		goto out_cleanup;

	ovl_dentry_update(dentry, newdentry);
	newdentry = NULL;

	/*
	 * Non-directores become opaque when copied up.
	 */
	if (!S_ISDIR(stat->mode))
		ovl_dentry_set_opaque(dentry, true);
out2:
	dput(upper);
out1:
	dput(newdentry);
out:
	return err;

out_cleanup:
	ovl_cleanup(wdir, newdentry);
	goto out2;
}

/*
 * Copy up a single dentry
 *
 * Directory renames only allowed on "pure upper" (already created on
 * upper filesystem, never copied up).  Directories which are on lower or
 * are merged may not be renamed.  For these -EXDEV is returned and
 * userspace has to deal with it.  This means, when copying up a
 * directory we can rely on it and ancestors being stable.
 *
 * Non-directory renames start with copy up of source if necessary.  The
 * actual rename will only proceed once the copy up was successful.  Copy
 * up uses upper parent i_mutex for exclusion.  Since rename can change
 * d_parent it is possible that the copy up will lock the old parent.  At
 * that point the file will have already been copied up anyway.
 */
int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
		    struct path *lowerpath, struct kstat *stat)
{
	struct dentry *workdir = ovl_workdir(dentry);
	int err;
	struct kstat pstat;
	struct path parentpath;
	struct dentry *upperdir;
	struct dentry *upperdentry;
	const struct cred *old_cred;
	struct cred *override_cred;
	char *link = NULL;

	if (WARN_ON(!workdir))
		return -EROFS;

	ovl_path_upper(parent, &parentpath);
	upperdir = parentpath.dentry;

	err = vfs_getattr(&parentpath, &pstat);
	if (err)
		return err;

	if (S_ISLNK(stat->mode)) {
		link = ovl_read_symlink(lowerpath->dentry);
		if (IS_ERR(link))
			return PTR_ERR(link);
	}

	err = -ENOMEM;
	override_cred = prepare_creds();
	if (!override_cred)
		goto out_free_link;

	override_cred->fsuid = stat->uid;
	override_cred->fsgid = stat->gid;
	/*
	 * CAP_SYS_ADMIN for copying up extended attributes
	 * CAP_DAC_OVERRIDE for create
	 * CAP_FOWNER for chmod, timestamp update
	 * CAP_FSETID for chmod
	 * CAP_CHOWN for chown
	 * CAP_MKNOD for mknod
	 */
	cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
	cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
	cap_raise(override_cred->cap_effective, CAP_FOWNER);
	cap_raise(override_cred->cap_effective, CAP_FSETID);
	cap_raise(override_cred->cap_effective, CAP_CHOWN);
	cap_raise(override_cred->cap_effective, CAP_MKNOD);
	old_cred = override_creds(override_cred);

	err = -EIO;
	if (lock_rename(workdir, upperdir) != NULL) {
		pr_err("overlayfs: failed to lock workdir+upperdir\n");
		goto out_unlock;
	}
	upperdentry = ovl_dentry_upper(dentry);
	if (upperdentry) {
		/* Raced with another copy-up?  Nothing to do, then... */
		err = 0;
		goto out_unlock;
	}

	err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
				 stat, link);
	if (!err) {
		/* Restore timestamps on parent (best effort) */
		ovl_set_timestamps(upperdir, &pstat);
	}
out_unlock:
	unlock_rename(workdir, upperdir);
	revert_creds(old_cred);
	put_cred(override_cred);

out_free_link:
	if (link)
		free_page((unsigned long) link);

	return err;
}

int ovl_copy_up(struct dentry *dentry)
{
	int err;

	err = 0;
	while (!err) {
		struct dentry *next;
		struct dentry *parent;
		struct path lowerpath;
		struct kstat stat;
		enum ovl_path_type type = ovl_path_type(dentry);

		if (OVL_TYPE_UPPER(type))
			break;

		next = dget(dentry);
		/* find the topmost dentry not yet copied up */
		for (;;) {
			parent = dget_parent(next);

			type = ovl_path_type(parent);
			if (OVL_TYPE_UPPER(type))
				break;

			dput(next);
			next = parent;
		}

		ovl_path_lower(next, &lowerpath);
		err = vfs_getattr(&lowerpath, &stat);
		if (!err)
			err = ovl_copy_up_one(parent, next, &lowerpath, &stat);

		dput(parent);
		dput(next);
	}

	return err;
}
Commit	Line	Data
e9be9d5e MS	1	/*
	2	*
	3	* Copyright (C) 2011 Novell Inc.
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU General Public License version 2 as published by
	7	* the Free Software Foundation.
	8	*/
	9
	10	#include <linux/fs.h>
	11	#include <linux/slab.h>
	12	#include <linux/file.h>
	13	#include <linux/splice.h>
	14	#include <linux/xattr.h>
	15	#include <linux/security.h>
	16	#include <linux/uaccess.h>
	17	#include <linux/sched.h>
	18	#include <linux/namei.h>
	19	#include "overlayfs.h"
	20
	21	#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
	22
	23	int ovl_copy_xattr(struct dentry old, struct dentry new)
	24	{
e4ad29fa VC	25	ssize_t list_size, size, value_size = 0;
	26	char buf, name, *value = NULL;
	27	int uninitialized_var(error);
e9be9d5e MS	28
	29	if (!old->d_inode->i_op->getxattr \|\|
	30	!new->d_inode->i_op->getxattr)
	31	return 0;
	32
	33	list_size = vfs_listxattr(old, NULL, 0);
	34	if (list_size <= 0) {
	35	if (list_size == -EOPNOTSUPP)
	36	return 0;
	37	return list_size;
	38	}
	39
	40	buf = kzalloc(list_size, GFP_KERNEL);
	41	if (!buf)
	42	return -ENOMEM;
	43
e9be9d5e MS	44	list_size = vfs_listxattr(old, buf, list_size);
	45	if (list_size <= 0) {
	46	error = list_size;
e4ad29fa	47	goto out;
e9be9d5e MS	48	}
	49
	50	for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {
e4ad29fa VC	51	retry:
	52	size = vfs_getxattr(old, name, value, value_size);
	53	if (size == -ERANGE)
	54	size = vfs_getxattr(old, name, NULL, 0);
	55
97daf8b9	56	if (size < 0) {
e9be9d5e	57	error = size;
e4ad29fa	58	break;
e9be9d5e	59	}
e4ad29fa VC	60
	61	if (size > value_size) {
	62	void *new;
	63
	64	new = krealloc(value, size, GFP_KERNEL);
	65	if (!new) {
	66	error = -ENOMEM;
	67	break;
	68	}
	69	value = new;
	70	value_size = size;
	71	goto retry;
	72	}
	73
e9be9d5e MS	74	error = vfs_setxattr(new, name, value, size, 0);
e9be9d5e MS	75	if (error)
e4ad29fa	76	break;
e9be9d5e	77	}
e9be9d5e MS	78	kfree(value);
	79	out:
	80	kfree(buf);
	81	return error;
	82	}
	83
	84	static int ovl_copy_up_data(struct path old, struct path new, loff_t len)
	85	{
	86	struct file *old_file;
	87	struct file *new_file;
	88	loff_t old_pos = 0;
	89	loff_t new_pos = 0;
	90	int error = 0;
	91
	92	if (len == 0)
	93	return 0;
	94
0480334f	95	old_file = ovl_path_open(old, O_LARGEFILE \| O_RDONLY);
e9be9d5e MS	96	if (IS_ERR(old_file))
	97	return PTR_ERR(old_file);
	98
0480334f	99	new_file = ovl_path_open(new, O_LARGEFILE \| O_WRONLY);
e9be9d5e MS	100	if (IS_ERR(new_file)) {
	101	error = PTR_ERR(new_file);
	102	goto out_fput;
	103	}
	104
	105	/* FIXME: copy up sparse files efficiently */
	106	while (len) {
	107	size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
	108	long bytes;
	109
	110	if (len < this_len)
	111	this_len = len;
	112
	113	if (signal_pending_state(TASK_KILLABLE, current)) {
	114	error = -EINTR;
	115	break;
	116	}
	117
	118	bytes = do_splice_direct(old_file, &old_pos,
	119	new_file, &new_pos,
	120	this_len, SPLICE_F_MOVE);
	121	if (bytes <= 0) {
	122	error = bytes;
	123	break;
	124	}
	125	WARN_ON(old_pos != new_pos);
	126
	127	len -= bytes;
	128	}
	129
	130	fput(new_file);
	131	out_fput:
	132	fput(old_file);
	133	return error;
	134	}
	135
	136	static char ovl_read_symlink(struct dentry realdentry)
	137	{
	138	int res;
	139	char *buf;
	140	struct inode *inode = realdentry->d_inode;
	141	mm_segment_t old_fs;
	142
	143	res = -EINVAL;
	144	if (!inode->i_op->readlink)
	145	goto err;
	146
	147	res = -ENOMEM;
	148	buf = (char *) __get_free_page(GFP_KERNEL);
	149	if (!buf)
	150	goto err;
	151
	152	old_fs = get_fs();
	153	set_fs(get_ds());
	154	/* The cast to a user pointer is valid due to the set_fs() */
	155	res = inode->i_op->readlink(realdentry,
	156	(char __user *)buf, PAGE_SIZE - 1);
	157	set_fs(old_fs);
	158	if (res < 0) {
	159	free_page((unsigned long) buf);
	160	goto err;
	161	}
	162	buf[res] = '\0';
	163
164	return buf;
165
166	err:
167	return ERR_PTR(res);
168	}
169
170	static int ovl_set_timestamps(struct dentry upperdentry, struct kstat stat)
171	{
172	struct iattr attr = {
173	.ia_valid =
174	ATTR_ATIME \| ATTR_MTIME \| ATTR_ATIME_SET \| ATTR_MTIME_SET,
175	.ia_atime = stat->atime,
176	.ia_mtime = stat->mtime,
177	};
178
179	return notify_change(upperdentry, &attr, NULL);
180	}
181
182	int ovl_set_attr(struct dentry upperdentry, struct kstat stat)
183	{
184	int err = 0;
185
186	if (!S_ISLNK(stat->mode)) {
187	struct iattr attr = {
188	.ia_valid = ATTR_MODE,
189	.ia_mode = stat->mode,
190	};
191	err = notify_change(upperdentry, &attr, NULL);
192	}
193	if (!err) {
194	struct iattr attr = {
195	.ia_valid = ATTR_UID \| ATTR_GID,
196	.ia_uid = stat->uid,
197	.ia_gid = stat->gid,
198	};
199	err = notify_change(upperdentry, &attr, NULL);
200	}
201	if (!err)
202	ovl_set_timestamps(upperdentry, stat);
203
204	return err;
e9be9d5e MS	205	}
	206
	207	static int ovl_copy_up_locked(struct dentry workdir, struct dentry upperdir,
	208	struct dentry dentry, struct path lowerpath,
0f7ff2da	209	struct kstat stat, const char link)
e9be9d5e MS	210	{
	211	struct inode *wdir = workdir->d_inode;
	212	struct inode *udir = upperdir->d_inode;
	213	struct dentry *newdentry = NULL;
	214	struct dentry *upper = NULL;
	215	umode_t mode = stat->mode;
	216	int err;
	217
	218	newdentry = ovl_lookup_temp(workdir, dentry);
	219	err = PTR_ERR(newdentry);
	220	if (IS_ERR(newdentry))
	221	goto out;
	222
	223	upper = lookup_one_len(dentry->d_name.name, upperdir,
	224	dentry->d_name.len);
	225	err = PTR_ERR(upper);
	226	if (IS_ERR(upper))
	227	goto out1;
	228
	229	/* Can't properly set mode on creation because of the umask */
	230	stat->mode &= S_IFMT;
	231	err = ovl_create_real(wdir, newdentry, stat, link, NULL, true);
	232	stat->mode = mode;
	233	if (err)
	234	goto out2;
	235
	236	if (S_ISREG(stat->mode)) {
	237	struct path upperpath;
	238	ovl_path_upper(dentry, &upperpath);
	239	BUG_ON(upperpath.dentry != NULL);
	240	upperpath.dentry = newdentry;
	241
	242	err = ovl_copy_up_data(lowerpath, &upperpath, stat->size);
	243	if (err)
	244	goto out_cleanup;
	245	}
	246
	247	err = ovl_copy_xattr(lowerpath->dentry, newdentry);
	248	if (err)
	249	goto out_cleanup;
	250
5955102c	251	inode_lock(newdentry->d_inode);
e9be9d5e	252	err = ovl_set_attr(newdentry, stat);
5955102c	253	inode_unlock(newdentry->d_inode);
e9be9d5e MS	254	if (err)
	255	goto out_cleanup;
	256
	257	err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
	258	if (err)
	259	goto out_cleanup;
	260
	261	ovl_dentry_update(dentry, newdentry);
	262	newdentry = NULL;
	263
	264	/*
	265	* Non-directores become opaque when copied up.
	266	*/
	267	if (!S_ISDIR(stat->mode))
	268	ovl_dentry_set_opaque(dentry, true);
	269	out2:
	270	dput(upper);
	271	out1:
	272	dput(newdentry);
	273	out:
	274	return err;
	275
	276	out_cleanup:
	277	ovl_cleanup(wdir, newdentry);
ab79efab	278	goto out2;
e9be9d5e MS	279	}
	280
	281	/*
	282	* Copy up a single dentry
	283	*
	284	* Directory renames only allowed on "pure upper" (already created on
	285	* upper filesystem, never copied up). Directories which are on lower or
	286	* are merged may not be renamed. For these -EXDEV is returned and
	287	* userspace has to deal with it. This means, when copying up a
	288	* directory we can rely on it and ancestors being stable.
	289	*
	290	* Non-directory renames start with copy up of source if necessary. The
	291	* actual rename will only proceed once the copy up was successful. Copy
	292	* up uses upper parent i_mutex for exclusion. Since rename can change
	293	* d_parent it is possible that the copy up will lock the old parent. At
	294	* that point the file will have already been copied up anyway.
	295	*/
	296	int ovl_copy_up_one(struct dentry parent, struct dentry dentry,
0f7ff2da	297	struct path lowerpath, struct kstat stat)
e9be9d5e MS	298	{
	299	struct dentry *workdir = ovl_workdir(dentry);
	300	int err;
	301	struct kstat pstat;
	302	struct path parentpath;
	303	struct dentry *upperdir;
	304	struct dentry *upperdentry;
	305	const struct cred *old_cred;
	306	struct cred *override_cred;
	307	char *link = NULL;
	308
cc6f67bc MS	309	if (WARN_ON(!workdir))
	310	return -EROFS;
	311
e9be9d5e MS	312	ovl_path_upper(parent, &parentpath);
	313	upperdir = parentpath.dentry;
	314
	315	err = vfs_getattr(&parentpath, &pstat);
	316	if (err)
	317	return err;
	318
	319	if (S_ISLNK(stat->mode)) {
	320	link = ovl_read_symlink(lowerpath->dentry);
	321	if (IS_ERR(link))
	322	return PTR_ERR(link);
	323	}
	324
	325	err = -ENOMEM;
	326	override_cred = prepare_creds();
	327	if (!override_cred)
	328	goto out_free_link;
	329
	330	override_cred->fsuid = stat->uid;
	331	override_cred->fsgid = stat->gid;
	332	/*
	333	* CAP_SYS_ADMIN for copying up extended attributes
	334	* CAP_DAC_OVERRIDE for create
	335	* CAP_FOWNER for chmod, timestamp update
	336	* CAP_FSETID for chmod
	337	* CAP_CHOWN for chown
	338	* CAP_MKNOD for mknod
	339	*/
	340	cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
	341	cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
	342	cap_raise(override_cred->cap_effective, CAP_FOWNER);
	343	cap_raise(override_cred->cap_effective, CAP_FSETID);
	344	cap_raise(override_cred->cap_effective, CAP_CHOWN);
	345	cap_raise(override_cred->cap_effective, CAP_MKNOD);
	346	old_cred = override_creds(override_cred);
	347
	348	err = -EIO;
	349	if (lock_rename(workdir, upperdir) != NULL) {
	350	pr_err("overlayfs: failed to lock workdir+upperdir\n");
	351	goto out_unlock;
	352	}
	353	upperdentry = ovl_dentry_upper(dentry);
	354	if (upperdentry) {
0f7ff2da	355	/* Raced with another copy-up? Nothing to do, then... */
e9be9d5e	356	err = 0;
0f7ff2da	357	goto out_unlock;
e9be9d5e MS	358	}
	359
	360	err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
0f7ff2da	361	stat, link);
e9be9d5e MS	362	if (!err) {
	363	/* Restore timestamps on parent (best effort) */
	364	ovl_set_timestamps(upperdir, &pstat);
	365	}
	366	out_unlock:
	367	unlock_rename(workdir, upperdir);
e9be9d5e MS	368	revert_creds(old_cred);
	369	put_cred(override_cred);
	370
	371	out_free_link:
	372	if (link)
	373	free_page((unsigned long) link);
	374
	375	return err;
	376	}
	377
	378	int ovl_copy_up(struct dentry *dentry)
	379	{
	380	int err;
	381
	382	err = 0;
	383	while (!err) {
	384	struct dentry *next;
	385	struct dentry *parent;
	386	struct path lowerpath;
	387	struct kstat stat;
	388	enum ovl_path_type type = ovl_path_type(dentry);
	389
1afaba1e	390	if (OVL_TYPE_UPPER(type))
e9be9d5e MS	391	break;
	392
	393	next = dget(dentry);
	394	/* find the topmost dentry not yet copied up */
	395	for (;;) {
	396	parent = dget_parent(next);
	397
	398	type = ovl_path_type(parent);
1afaba1e	399	if (OVL_TYPE_UPPER(type))
e9be9d5e MS	400	break;
	401
	402	dput(next);
	403	next = parent;
	404	}
	405
	406	ovl_path_lower(next, &lowerpath);
	407	err = vfs_getattr(&lowerpath, &stat);
	408	if (!err)
0f7ff2da	409	err = ovl_copy_up_one(parent, next, &lowerpath, &stat);
e9be9d5e MS	410
	411	dput(parent);
	412	dput(next);
	413	}
	414
	415	return err;
	416	}