[mirror_ubuntu-artful-kernel.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/module.h>
#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/signal.h>
#include <linux/cred.h>
#include <linux/namei.h>
#include <linux/fdtable.h>
#include <linux/ratelimit.h>
#include "overlayfs.h"
#include "ovl_entry.h"

#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)

static bool __read_mostly ovl_check_copy_up;
module_param_named(check_copy_up, ovl_check_copy_up, bool,
		   S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(ovl_check_copy_up,
		 "Warn on copy-up when causing process also has a R/O fd open");

static int ovl_check_fd(const void *data, struct file *f, unsigned int fd)
{
	const struct dentry *dentry = data;

	if (file_inode(f) == d_inode(dentry))
		pr_warn_ratelimited("overlayfs: Warning: Copying up %pD, but open R/O on fd %u which will cease to be coherent [pid=%d %s]\n",
				    f, fd, current->pid, current->comm);
	return 0;
}

/*
 * Check the fds open by this process and warn if something like the following
 * scenario is about to occur:
 *
 *	fd1 = open("foo", O_RDONLY);
 *	fd2 = open("foo", O_RDWR);
 */
static void ovl_do_check_copy_up(struct dentry *dentry)
{
	if (ovl_check_copy_up)
		iterate_fd(current->files, 0, ovl_check_fd, dentry);
}

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);
	size_t slen;

	if (!(old->d_inode->i_opflags & IOP_XATTR) ||
	    !(new->d_inode->i_opflags & IOP_XATTR))
		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; list_size; name += slen) {
		slen = strnlen(name, list_size) + 1;

		/* underlying fs providing us with an broken xattr list? */
		if (WARN_ON(slen > list_size)) {
			error = -EIO;
			break;
		}
		list_size -= slen;

		if (ovl_is_private_xattr(name))
			continue;
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 = security_inode_copy_up_xattr(name);
		if (error < 0 && error != -EOPNOTSUPP)
			break;
		if (error == 1) {
			error = 0;
			continue; /* Discard */
		}
		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;
	}

	/* Try to use clone_file_range to clone up within the same fs */
	error = vfs_clone_file_range(old_file, 0, new_file, 0, len);
	if (!error)
		goto out;
	/* Couldn't clone, so now we try to copy the data */
	error = 0;

	/* 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;
	}
out:
	if (!error)
		error = vfs_fsync(new_file, 0);
	fput(new_file);
out_fput:
	fput(old_file);
	return error;
}

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 kstat *pstat, bool tmpfile)
{
	struct inode *wdir = workdir->d_inode;
	struct inode *udir = upperdir->d_inode;
	struct dentry *newdentry = NULL;
	struct dentry *upper = NULL;
	struct dentry *temp = NULL;
	int err;
	const struct cred *old_creds = NULL;
	struct cred *new_creds = NULL;
	struct cattr cattr = {
		/* Can't properly set mode on creation because of the umask */
		.mode = stat->mode & S_IFMT,
		.rdev = stat->rdev,
		.link = link
	};

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

	err = security_inode_copy_up(dentry, &new_creds);
	if (err < 0)
		goto out1;

	if (new_creds)
		old_creds = override_creds(new_creds);

	if (tmpfile)
		temp = ovl_do_tmpfile(upperdir, stat->mode);
	else
		temp = ovl_lookup_temp(workdir, dentry);
	err = PTR_ERR(temp);
	if (IS_ERR(temp))
		goto out1;

	err = 0;
	if (!tmpfile)
		err = ovl_create_real(wdir, temp, &cattr, NULL, true);

	if (new_creds) {
		revert_creds(old_creds);
		put_cred(new_creds);
	}

	if (err)
		goto out2;

	if (S_ISREG(stat->mode)) {
		struct path upperpath;

		ovl_path_upper(dentry, &upperpath);
		BUG_ON(upperpath.dentry != NULL);
		upperpath.dentry = temp;

		if (tmpfile) {
			inode_unlock(udir);
			err = ovl_copy_up_data(lowerpath, &upperpath,
					       stat->size);
			inode_lock_nested(udir, I_MUTEX_PARENT);
		} else {
			err = ovl_copy_up_data(lowerpath, &upperpath,
					       stat->size);
		}

		if (err)
			goto out_cleanup;
	}

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

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

	if (tmpfile)
		err = ovl_do_link(temp, udir, upper, true);
	else
		err = ovl_do_rename(wdir, temp, udir, upper, 0);
	if (err)
		goto out_cleanup;

	newdentry = dget(tmpfile ? upper : temp);
	ovl_dentry_update(dentry, newdentry);
	ovl_inode_update(d_inode(dentry), d_inode(newdentry));

	/* Restore timestamps on parent (best effort) */
	ovl_set_timestamps(upperdir, pstat);
out2:
	dput(temp);
out1:
	dput(upper);
out:
	return err;

out_cleanup:
	if (!tmpfile)
		ovl_cleanup(wdir, temp);
	goto out2;
}

/*
 * Copy up a single dentry
 *
 * All 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.
 */
static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
			   struct path *lowerpath, struct kstat *stat)
{
	DEFINE_DELAYED_CALL(done);
	struct dentry *workdir = ovl_workdir(dentry);
	int err;
	struct kstat pstat;
	struct path parentpath;
	struct dentry *lowerdentry = lowerpath->dentry;
	struct dentry *upperdir;
	const char *link = NULL;
	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;

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

	ovl_do_check_copy_up(lowerdentry);

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

	err = vfs_getattr(&parentpath, &pstat,
			  STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT);
	if (err)
		return err;

	if (S_ISLNK(stat->mode)) {
		link = vfs_get_link(lowerdentry, &done);
		if (IS_ERR(link))
			return PTR_ERR(link);
	}

	/* Should we copyup with O_TMPFILE or with workdir? */
	if (S_ISREG(stat->mode) && ofs->tmpfile) {
		err = ovl_copy_up_start(dentry);
		/* err < 0: interrupted, err > 0: raced with another copy-up */
		if (unlikely(err)) {
			pr_debug("ovl_copy_up_start(%pd2) = %i\n", dentry, err);
			if (err > 0)
				err = 0;
			goto out_done;
		}

		inode_lock_nested(upperdir->d_inode, I_MUTEX_PARENT);
		err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
					 stat, link, &pstat, true);
		inode_unlock(upperdir->d_inode);
		ovl_copy_up_end(dentry);
		goto out_done;
	}

	err = -EIO;
	if (lock_rename(workdir, upperdir) != NULL) {
		pr_err("overlayfs: failed to lock workdir+upperdir\n");
		goto out_unlock;
	}
	if (ovl_dentry_upper(dentry)) {
		/* 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, &pstat, false);
out_unlock:
	unlock_rename(workdir, upperdir);
out_done:
	do_delayed_call(&done);

	return err;
}

int ovl_copy_up_flags(struct dentry *dentry, int flags)
{
	int err = 0;
	const struct cred *old_cred = ovl_override_creds(dentry->d_sb);

	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,
				  STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
		/* maybe truncate regular file. this has no effect on dirs */
		if (flags & O_TRUNC)
			stat.size = 0;
		if (!err)
			err = ovl_copy_up_one(parent, next, &lowerpath, &stat);

		dput(parent);
		dput(next);
	}
	revert_creds(old_cred);

	return err;
}

int ovl_copy_up(struct dentry *dentry)
{
	return ovl_copy_up_flags(dentry, 0);
}
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
fb5bb2c3	10	#include <linux/module.h>
e9be9d5e MS	11	#include <linux/fs.h>
	12	#include <linux/slab.h>
	13	#include <linux/file.h>
	14	#include <linux/splice.h>
	15	#include <linux/xattr.h>
	16	#include <linux/security.h>
	17	#include <linux/uaccess.h>
174cd4b1	18	#include <linux/sched/signal.h>
5b825c3a	19	#include <linux/cred.h>
e9be9d5e	20	#include <linux/namei.h>
fb5bb2c3 DH	21	#include <linux/fdtable.h>
fb5bb2c3 DH	22	#include <linux/ratelimit.h>
e9be9d5e	23	#include "overlayfs.h"
d8514d8e	24	#include "ovl_entry.h"
e9be9d5e MS	25
	26	#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
	27
fb5bb2c3 DH	28	static bool __read_mostly ovl_check_copy_up;
	29	module_param_named(check_copy_up, ovl_check_copy_up, bool,
	30	S_IWUSR \| S_IRUGO);
	31	MODULE_PARM_DESC(ovl_check_copy_up,
	32	"Warn on copy-up when causing process also has a R/O fd open");
	33
	34	static int ovl_check_fd(const void data, struct file f, unsigned int fd)
	35	{
	36	const struct dentry *dentry = data;
	37
45063097	38	if (file_inode(f) == d_inode(dentry))
fb5bb2c3 DH	39	pr_warn_ratelimited("overlayfs: Warning: Copying up %pD, but open R/O on fd %u which will cease to be coherent [pid=%d %s]\n",
	40	f, fd, current->pid, current->comm);
	41	return 0;
	42	}
	43
	44	/*
	45	* Check the fds open by this process and warn if something like the following
	46	* scenario is about to occur:
	47	*
	48	* fd1 = open("foo", O_RDONLY);
	49	* fd2 = open("foo", O_RDWR);
	50	*/
	51	static void ovl_do_check_copy_up(struct dentry *dentry)
	52	{
	53	if (ovl_check_copy_up)
	54	iterate_fd(current->files, 0, ovl_check_fd, dentry);
	55	}
	56
e9be9d5e MS	57	int ovl_copy_xattr(struct dentry old, struct dentry new)
e9be9d5e MS	58	{
e4ad29fa VC	59	ssize_t list_size, size, value_size = 0;
	60	char buf, name, *value = NULL;
	61	int uninitialized_var(error);
8b326c61	62	size_t slen;
e9be9d5e	63
5d6c3191 AG	64	if (!(old->d_inode->i_opflags & IOP_XATTR) \|\|
5d6c3191 AG	65	!(new->d_inode->i_opflags & IOP_XATTR))
e9be9d5e MS	66	return 0;
	67
	68	list_size = vfs_listxattr(old, NULL, 0);
	69	if (list_size <= 0) {
	70	if (list_size == -EOPNOTSUPP)
	71	return 0;
	72	return list_size;
	73	}
	74
	75	buf = kzalloc(list_size, GFP_KERNEL);
	76	if (!buf)
	77	return -ENOMEM;
	78
e9be9d5e MS	79	list_size = vfs_listxattr(old, buf, list_size);
	80	if (list_size <= 0) {
	81	error = list_size;
e4ad29fa	82	goto out;
e9be9d5e MS	83	}
e9be9d5e MS	84
8b326c61 MS	85	for (name = buf; list_size; name += slen) {
	86	slen = strnlen(name, list_size) + 1;
	87
	88	/* underlying fs providing us with an broken xattr list? */
	89	if (WARN_ON(slen > list_size)) {
	90	error = -EIO;
	91	break;
	92	}
	93	list_size -= slen;
	94
0956254a MS	95	if (ovl_is_private_xattr(name))
0956254a MS	96	continue;
e4ad29fa VC	97	retry:
	98	size = vfs_getxattr(old, name, value, value_size);
	99	if (size == -ERANGE)
	100	size = vfs_getxattr(old, name, NULL, 0);
	101
97daf8b9	102	if (size < 0) {
e9be9d5e	103	error = size;
e4ad29fa	104	break;
e9be9d5e	105	}
e4ad29fa VC	106
	107	if (size > value_size) {
	108	void *new;
	109
	110	new = krealloc(value, size, GFP_KERNEL);
	111	if (!new) {
	112	error = -ENOMEM;
	113	break;
	114	}
	115	value = new;
	116	value_size = size;
	117	goto retry;
	118	}
	119
121ab822 VG	120	error = security_inode_copy_up_xattr(name);
	121	if (error < 0 && error != -EOPNOTSUPP)
	122	break;
	123	if (error == 1) {
	124	error = 0;
	125	continue; /* Discard */
	126	}
e9be9d5e MS	127	error = vfs_setxattr(new, name, value, size, 0);
e9be9d5e MS	128	if (error)
e4ad29fa	129	break;
e9be9d5e	130	}
e9be9d5e MS	131	kfree(value);
	132	out:
	133	kfree(buf);
	134	return error;
	135	}
	136
	137	static int ovl_copy_up_data(struct path old, struct path new, loff_t len)
	138	{
	139	struct file *old_file;
	140	struct file *new_file;
	141	loff_t old_pos = 0;
	142	loff_t new_pos = 0;
	143	int error = 0;
	144
	145	if (len == 0)
	146	return 0;
	147
0480334f	148	old_file = ovl_path_open(old, O_LARGEFILE \| O_RDONLY);
e9be9d5e MS	149	if (IS_ERR(old_file))
	150	return PTR_ERR(old_file);
	151
0480334f	152	new_file = ovl_path_open(new, O_LARGEFILE \| O_WRONLY);
e9be9d5e MS	153	if (IS_ERR(new_file)) {
	154	error = PTR_ERR(new_file);
	155	goto out_fput;
	156	}
	157
2ea98466 AG	158	/* Try to use clone_file_range to clone up within the same fs */
	159	error = vfs_clone_file_range(old_file, 0, new_file, 0, len);
	160	if (!error)
	161	goto out;
	162	/* Couldn't clone, so now we try to copy the data */
	163	error = 0;
	164
e9be9d5e MS	165	/* FIXME: copy up sparse files efficiently */
	166	while (len) {
	167	size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
	168	long bytes;
	169
	170	if (len < this_len)
	171	this_len = len;
	172
	173	if (signal_pending_state(TASK_KILLABLE, current)) {
	174	error = -EINTR;
	175	break;
	176	}
	177
	178	bytes = do_splice_direct(old_file, &old_pos,
	179	new_file, &new_pos,
	180	this_len, SPLICE_F_MOVE);
	181	if (bytes <= 0) {
	182	error = bytes;
	183	break;
	184	}
	185	WARN_ON(old_pos != new_pos);
	186
	187	len -= bytes;
	188	}
2ea98466	189	out:
641089c1 MS	190	if (!error)
641089c1 MS	191	error = vfs_fsync(new_file, 0);
e9be9d5e MS	192	fput(new_file);
	193	out_fput:
	194	fput(old_file);
	195	return error;
	196	}
	197
e9be9d5e MS	198	static int ovl_set_timestamps(struct dentry upperdentry, struct kstat stat)
	199	{
	200	struct iattr attr = {
	201	.ia_valid =
	202	ATTR_ATIME \| ATTR_MTIME \| ATTR_ATIME_SET \| ATTR_MTIME_SET,
	203	.ia_atime = stat->atime,
	204	.ia_mtime = stat->mtime,
	205	};
	206
	207	return notify_change(upperdentry, &attr, NULL);
	208	}
	209
	210	int ovl_set_attr(struct dentry upperdentry, struct kstat stat)
	211	{
	212	int err = 0;
	213
	214	if (!S_ISLNK(stat->mode)) {
	215	struct iattr attr = {
	216	.ia_valid = ATTR_MODE,
	217	.ia_mode = stat->mode,
	218	};
	219	err = notify_change(upperdentry, &attr, NULL);
	220	}
	221	if (!err) {
	222	struct iattr attr = {
	223	.ia_valid = ATTR_UID \| ATTR_GID,
	224	.ia_uid = stat->uid,
	225	.ia_gid = stat->gid,
	226	};
	227	err = notify_change(upperdentry, &attr, NULL);
	228	}
	229	if (!err)
	230	ovl_set_timestamps(upperdentry, stat);
	231
	232	return err;
e9be9d5e MS	233	}
	234
	235	static int ovl_copy_up_locked(struct dentry workdir, struct dentry upperdir,
	236	struct dentry dentry, struct path lowerpath,
42f269b9	237	struct kstat stat, const char link,
d8514d8e	238	struct kstat *pstat, bool tmpfile)
e9be9d5e MS	239	{
	240	struct inode *wdir = workdir->d_inode;
	241	struct inode *udir = upperdir->d_inode;
	242	struct dentry *newdentry = NULL;
	243	struct dentry *upper = NULL;
42f269b9	244	struct dentry *temp = NULL;
e9be9d5e	245	int err;
d8ad8b49 VG	246	const struct cred *old_creds = NULL;
d8ad8b49 VG	247	struct cred *new_creds = NULL;
32a3d848 AV	248	struct cattr cattr = {
	249	/* Can't properly set mode on creation because of the umask */
	250	.mode = stat->mode & S_IFMT,
	251	.rdev = stat->rdev,
	252	.link = link
	253	};
e9be9d5e	254
e9be9d5e MS	255	upper = lookup_one_len(dentry->d_name.name, upperdir,
	256	dentry->d_name.len);
	257	err = PTR_ERR(upper);
	258	if (IS_ERR(upper))
42f269b9	259	goto out;
e9be9d5e	260
d8ad8b49 VG	261	err = security_inode_copy_up(dentry, &new_creds);
d8ad8b49 VG	262	if (err < 0)
42f269b9	263	goto out1;
d8ad8b49 VG	264
	265	if (new_creds)
	266	old_creds = override_creds(new_creds);
	267
d8514d8e AG	268	if (tmpfile)
	269	temp = ovl_do_tmpfile(upperdir, stat->mode);
	270	else
	271	temp = ovl_lookup_temp(workdir, dentry);
42f269b9 AG	272	err = PTR_ERR(temp);
	273	if (IS_ERR(temp))
	274	goto out1;
	275
d8514d8e AG	276	err = 0;
	277	if (!tmpfile)
	278	err = ovl_create_real(wdir, temp, &cattr, NULL, true);
d8ad8b49 VG	279
	280	if (new_creds) {
	281	revert_creds(old_creds);
	282	put_cred(new_creds);
	283	}
	284
e9be9d5e MS	285	if (err)
	286	goto out2;
	287
	288	if (S_ISREG(stat->mode)) {
	289	struct path upperpath;
f134f244	290
e9be9d5e MS	291	ovl_path_upper(dentry, &upperpath);
e9be9d5e MS	292	BUG_ON(upperpath.dentry != NULL);
42f269b9	293	upperpath.dentry = temp;
e9be9d5e	294
01ad3eb8 AG	295	if (tmpfile) {
	296	inode_unlock(udir);
	297	err = ovl_copy_up_data(lowerpath, &upperpath,
	298	stat->size);
	299	inode_lock_nested(udir, I_MUTEX_PARENT);
	300	} else {
	301	err = ovl_copy_up_data(lowerpath, &upperpath,
	302	stat->size);
	303	}
e9be9d5e	304
e9be9d5e MS	305	if (err)
	306	goto out_cleanup;
	307	}
	308
42f269b9	309	err = ovl_copy_xattr(lowerpath->dentry, temp);
e9be9d5e MS	310	if (err)
	311	goto out_cleanup;
	312
42f269b9 AG	313	inode_lock(temp->d_inode);
	314	err = ovl_set_attr(temp, stat);
	315	inode_unlock(temp->d_inode);
e9be9d5e MS	316	if (err)
	317	goto out_cleanup;
	318
d8514d8e AG	319	if (tmpfile)
	320	err = ovl_do_link(temp, udir, upper, true);
	321	else
	322	err = ovl_do_rename(wdir, temp, udir, upper, 0);
e9be9d5e MS	323	if (err)
	324	goto out_cleanup;
	325
d8514d8e	326	newdentry = dget(tmpfile ? upper : temp);
e9be9d5e	327	ovl_dentry_update(dentry, newdentry);
39b681f8	328	ovl_inode_update(d_inode(dentry), d_inode(newdentry));
42f269b9 AG	329
	330	/* Restore timestamps on parent (best effort) */
	331	ovl_set_timestamps(upperdir, pstat);
e9be9d5e	332	out2:
42f269b9	333	dput(temp);
e9be9d5e	334	out1:
42f269b9	335	dput(upper);
e9be9d5e MS	336	out:
	337	return err;
	338
	339	out_cleanup:
d8514d8e AG	340	if (!tmpfile)
d8514d8e AG	341	ovl_cleanup(wdir, temp);
ab79efab	342	goto out2;
e9be9d5e MS	343	}
	344
	345	/*
	346	* Copy up a single dentry
	347	*
a6c60655 MS	348	* All renames start with copy up of source if necessary. The actual
	349	* rename will only proceed once the copy up was successful. Copy up uses
	350	* upper parent i_mutex for exclusion. Since rename can change d_parent it
	351	* is possible that the copy up will lock the old parent. At that point
	352	* the file will have already been copied up anyway.
e9be9d5e	353	*/
9aba6521 AG	354	static int ovl_copy_up_one(struct dentry parent, struct dentry dentry,
9aba6521 AG	355	struct path lowerpath, struct kstat stat)
e9be9d5e	356	{
7764235b	357	DEFINE_DELAYED_CALL(done);
e9be9d5e MS	358	struct dentry *workdir = ovl_workdir(dentry);
	359	int err;
	360	struct kstat pstat;
	361	struct path parentpath;
7764235b	362	struct dentry *lowerdentry = lowerpath->dentry;
e9be9d5e	363	struct dentry *upperdir;
7764235b	364	const char *link = NULL;
d8514d8e	365	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
e9be9d5e	366
cc6f67bc MS	367	if (WARN_ON(!workdir))
	368	return -EROFS;
	369
7764235b	370	ovl_do_check_copy_up(lowerdentry);
fb5bb2c3	371
e9be9d5e MS	372	ovl_path_upper(parent, &parentpath);
	373	upperdir = parentpath.dentry;
	374
a528d35e DH	375	err = vfs_getattr(&parentpath, &pstat,
a528d35e DH	376	STATX_ATIME \| STATX_MTIME, AT_STATX_SYNC_AS_STAT);
e9be9d5e MS	377	if (err)
	378	return err;
	379
	380	if (S_ISLNK(stat->mode)) {
7764235b	381	link = vfs_get_link(lowerdentry, &done);
e9be9d5e MS	382	if (IS_ERR(link))
	383	return PTR_ERR(link);
	384	}
	385
01ad3eb8 AG	386	/* Should we copyup with O_TMPFILE or with workdir? */
	387	if (S_ISREG(stat->mode) && ofs->tmpfile) {
	388	err = ovl_copy_up_start(dentry);
	389	/* err < 0: interrupted, err > 0: raced with another copy-up */
	390	if (unlikely(err)) {
	391	pr_debug("ovl_copy_up_start(%pd2) = %i\n", dentry, err);
	392	if (err > 0)
	393	err = 0;
	394	goto out_done;
	395	}
	396
	397	inode_lock_nested(upperdir->d_inode, I_MUTEX_PARENT);
	398	err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
	399	stat, link, &pstat, true);
	400	inode_unlock(upperdir->d_inode);
	401	ovl_copy_up_end(dentry);
	402	goto out_done;
	403	}
	404
e9be9d5e MS	405	err = -EIO;
	406	if (lock_rename(workdir, upperdir) != NULL) {
	407	pr_err("overlayfs: failed to lock workdir+upperdir\n");
	408	goto out_unlock;
	409	}
a6c60655	410	if (ovl_dentry_upper(dentry)) {
0f7ff2da	411	/* Raced with another copy-up? Nothing to do, then... */
e9be9d5e	412	err = 0;
0f7ff2da	413	goto out_unlock;
e9be9d5e MS	414	}
	415
	416	err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
01ad3eb8	417	stat, link, &pstat, false);
e9be9d5e MS	418	out_unlock:
e9be9d5e MS	419	unlock_rename(workdir, upperdir);
01ad3eb8	420	out_done:
7764235b	421	do_delayed_call(&done);
e9be9d5e MS	422
	423	return err;
	424	}
	425
9aba6521	426	int ovl_copy_up_flags(struct dentry *dentry, int flags)
e9be9d5e	427	{
8eac98b8 VG	428	int err = 0;
8eac98b8 VG	429	const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
e9be9d5e	430
e9be9d5e MS	431	while (!err) {
	432	struct dentry *next;
	433	struct dentry *parent;
	434	struct path lowerpath;
	435	struct kstat stat;
	436	enum ovl_path_type type = ovl_path_type(dentry);
	437
1afaba1e	438	if (OVL_TYPE_UPPER(type))
e9be9d5e MS	439	break;
	440
	441	next = dget(dentry);
	442	/* find the topmost dentry not yet copied up */
	443	for (;;) {
	444	parent = dget_parent(next);
	445
	446	type = ovl_path_type(parent);
1afaba1e	447	if (OVL_TYPE_UPPER(type))
e9be9d5e MS	448	break;
	449
	450	dput(next);
	451	next = parent;
	452	}
	453
	454	ovl_path_lower(next, &lowerpath);
a528d35e DH	455	err = vfs_getattr(&lowerpath, &stat,
a528d35e DH	456	STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
9aba6521 AG	457	/* maybe truncate regular file. this has no effect on dirs */
	458	if (flags & O_TRUNC)
	459	stat.size = 0;
e9be9d5e	460	if (!err)
0f7ff2da	461	err = ovl_copy_up_one(parent, next, &lowerpath, &stat);
e9be9d5e MS	462
	463	dput(parent);
	464	dput(next);
	465	}
8eac98b8	466	revert_creds(old_cred);
e9be9d5e MS	467
	468	return err;
	469	}
9aba6521 AG	470
	471	int ovl_copy_up(struct dentry *dentry)
	472	{
	473	return ovl_copy_up_flags(dentry, 0);
	474	}