[mirror_ubuntu-artful-kernel.git] / fs / overlayfs / inode.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/xattr.h>
#include "overlayfs.h"

static int ovl_copy_up_truncate(struct dentry *dentry)
{
	int err;
	struct dentry *parent;
	struct kstat stat;
	struct path lowerpath;

	parent = dget_parent(dentry);
	err = ovl_copy_up(parent);
	if (err)
		goto out_dput_parent;

	ovl_path_lower(dentry, &lowerpath);
	err = vfs_getattr(&lowerpath, &stat);
	if (err)
		goto out_dput_parent;

	stat.size = 0;
	err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);

out_dput_parent:
	dput(parent);
	return err;
}

int ovl_setattr(struct dentry *dentry, struct iattr *attr)
{
	int err;
	struct dentry *upperdentry;

	/*
	 * Check for permissions before trying to copy-up.  This is redundant
	 * since it will be rechecked later by ->setattr() on upper dentry.  But
	 * without this, copy-up can be triggered by just about anybody.
	 *
	 * We don't initialize inode->size, which just means that
	 * inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not
	 * check for a swapfile (which this won't be anyway).
	 */
	err = inode_change_ok(dentry->d_inode, attr);
	if (err)
		return err;

	err = ovl_want_write(dentry);
	if (err)
		goto out;

	err = ovl_copy_up(dentry);
	if (!err) {
		upperdentry = ovl_dentry_upper(dentry);

		inode_lock(upperdentry->d_inode);
		err = notify_change(upperdentry, attr, NULL);
		inode_unlock(upperdentry->d_inode);
	}
	ovl_drop_write(dentry);
out:
	return err;
}

static int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry,
			 struct kstat *stat)
{
	struct path realpath;

	ovl_path_real(dentry, &realpath);
	return vfs_getattr(&realpath, stat);
}

int ovl_permission(struct inode *inode, int mask)
{
	struct ovl_entry *oe;
	struct dentry *alias = NULL;
	struct inode *realinode;
	struct dentry *realdentry;
	bool is_upper;
	int err;

	if (S_ISDIR(inode->i_mode)) {
		oe = inode->i_private;
	} else if (mask & MAY_NOT_BLOCK) {
		return -ECHILD;
	} else {
		/*
		 * For non-directories find an alias and get the info
		 * from there.
		 */
		alias = d_find_any_alias(inode);
		if (WARN_ON(!alias))
			return -ENOENT;

		oe = alias->d_fsdata;
	}

	realdentry = ovl_entry_real(oe, &is_upper);

	if (ovl_is_default_permissions(inode)) {
		struct kstat stat;
		struct path realpath = { .dentry = realdentry };

		if (mask & MAY_NOT_BLOCK)
			return -ECHILD;

		realpath.mnt = ovl_entry_mnt_real(oe, inode, is_upper);

		err = vfs_getattr(&realpath, &stat);
		if (err)
			return err;

		if ((stat.mode ^ inode->i_mode) & S_IFMT)
			return -ESTALE;

		inode->i_mode = stat.mode;
		inode->i_uid = stat.uid;
		inode->i_gid = stat.gid;

		return generic_permission(inode, mask);
	}

	/* Careful in RCU walk mode */
	realinode = ACCESS_ONCE(realdentry->d_inode);
	if (!realinode) {
		WARN_ON(!(mask & MAY_NOT_BLOCK));
		err = -ENOENT;
		goto out_dput;
	}

	if (mask & MAY_WRITE) {
		umode_t mode = realinode->i_mode;

		/*
		 * Writes will always be redirected to upper layer, so
		 * ignore lower layer being read-only.
		 *
		 * If the overlay itself is read-only then proceed
		 * with the permission check, don't return EROFS.
		 * This will only happen if this is the lower layer of
		 * another overlayfs.
		 *
		 * If upper fs becomes read-only after the overlay was
		 * constructed return EROFS to prevent modification of
		 * upper layer.
		 */
		err = -EROFS;
		if (is_upper && !IS_RDONLY(inode) && IS_RDONLY(realinode) &&
		    (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
			goto out_dput;
	}

	err = __inode_permission(realinode, mask);
out_dput:
	dput(alias);
	return err;
}

static const char *ovl_get_link(struct dentry *dentry,
				struct inode *inode,
				struct delayed_call *done)
{
	struct dentry *realdentry;
	struct inode *realinode;

	if (!dentry)
		return ERR_PTR(-ECHILD);

	realdentry = ovl_dentry_real(dentry);
	realinode = realdentry->d_inode;

	if (WARN_ON(!realinode->i_op->get_link))
		return ERR_PTR(-EPERM);

	return realinode->i_op->get_link(realdentry, realinode, done);
}

static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
{
	struct path realpath;
	struct inode *realinode;

	ovl_path_real(dentry, &realpath);
	realinode = realpath.dentry->d_inode;

	if (!realinode->i_op->readlink)
		return -EINVAL;

	touch_atime(&realpath);

	return realinode->i_op->readlink(realpath.dentry, buf, bufsiz);
}


static bool ovl_is_private_xattr(const char *name)
{
	return strncmp(name, OVL_XATTR_PRE_NAME, OVL_XATTR_PRE_LEN) == 0;
}

int ovl_setxattr(struct dentry *dentry, const char *name,
		 const void *value, size_t size, int flags)
{
	int err;
	struct dentry *upperdentry;

	err = ovl_want_write(dentry);
	if (err)
		goto out;

	err = -EPERM;
	if (ovl_is_private_xattr(name))
		goto out_drop_write;

	err = ovl_copy_up(dentry);
	if (err)
		goto out_drop_write;

	upperdentry = ovl_dentry_upper(dentry);
	err = vfs_setxattr(upperdentry, name, value, size, flags);

out_drop_write:
	ovl_drop_write(dentry);
out:
	return err;
}

static bool ovl_need_xattr_filter(struct dentry *dentry,
				  enum ovl_path_type type)
{
	if ((type & (__OVL_PATH_PURE | __OVL_PATH_UPPER)) == __OVL_PATH_UPPER)
		return S_ISDIR(dentry->d_inode->i_mode);
	else
		return false;
}

ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
		     void *value, size_t size)
{
	struct path realpath;
	enum ovl_path_type type = ovl_path_real(dentry, &realpath);

	if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
		return -ENODATA;

	return vfs_getxattr(realpath.dentry, name, value, size);
}

ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
{
	struct path realpath;
	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
	ssize_t res;
	int off;

	res = vfs_listxattr(realpath.dentry, list, size);
	if (res <= 0 || size == 0)
		return res;

	if (!ovl_need_xattr_filter(dentry, type))
		return res;

	/* filter out private xattrs */
	for (off = 0; off < res;) {
		char *s = list + off;
		size_t slen = strlen(s) + 1;

		BUG_ON(off + slen > res);

		if (ovl_is_private_xattr(s)) {
			res -= slen;
			memmove(s, s + slen, res - off);
		} else {
			off += slen;
		}
	}

	return res;
}

int ovl_removexattr(struct dentry *dentry, const char *name)
{
	int err;
	struct path realpath;
	enum ovl_path_type type = ovl_path_real(dentry, &realpath);

	err = ovl_want_write(dentry);
	if (err)
		goto out;

	err = -ENODATA;
	if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
		goto out_drop_write;

	if (!OVL_TYPE_UPPER(type)) {
		err = vfs_getxattr(realpath.dentry, name, NULL, 0);
		if (err < 0)
			goto out_drop_write;

		err = ovl_copy_up(dentry);
		if (err)
			goto out_drop_write;

		ovl_path_upper(dentry, &realpath);
	}

	err = vfs_removexattr(realpath.dentry, name);
out_drop_write:
	ovl_drop_write(dentry);
out:
	return err;
}

static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,
				  struct dentry *realdentry)
{
	if (OVL_TYPE_UPPER(type))
		return false;

	if (special_file(realdentry->d_inode->i_mode))
		return false;

	if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC))
		return false;

	return true;
}

struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags)
{
	int err;
	struct path realpath;
	enum ovl_path_type type;

	if (d_is_dir(dentry))
		return d_backing_inode(dentry);

	type = ovl_path_real(dentry, &realpath);
	if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
		err = ovl_want_write(dentry);
		if (err)
			return ERR_PTR(err);

		if (file_flags & O_TRUNC)
			err = ovl_copy_up_truncate(dentry);
		else
			err = ovl_copy_up(dentry);
		ovl_drop_write(dentry);
		if (err)
			return ERR_PTR(err);

		ovl_path_upper(dentry, &realpath);
	}

	if (realpath.dentry->d_flags & DCACHE_OP_SELECT_INODE)
		return realpath.dentry->d_op->d_select_inode(realpath.dentry, file_flags);

	return d_backing_inode(realpath.dentry);
}

static const struct inode_operations ovl_file_inode_operations = {
	.setattr	= ovl_setattr,
	.permission	= ovl_permission,
	.getattr	= ovl_getattr,
	.setxattr	= ovl_setxattr,
	.getxattr	= ovl_getxattr,
	.listxattr	= ovl_listxattr,
	.removexattr	= ovl_removexattr,
};

static const struct inode_operations ovl_symlink_inode_operations = {
	.setattr	= ovl_setattr,
	.get_link	= ovl_get_link,
	.readlink	= ovl_readlink,
	.getattr	= ovl_getattr,
	.setxattr	= ovl_setxattr,
	.getxattr	= ovl_getxattr,
	.listxattr	= ovl_listxattr,
	.removexattr	= ovl_removexattr,
};

struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
			    struct ovl_entry *oe)
{
	struct inode *inode;

	inode = new_inode(sb);
	if (!inode)
		return NULL;

	mode &= S_IFMT;

	inode->i_ino = get_next_ino();
	inode->i_mode = mode;
	inode->i_flags |= S_NOATIME | S_NOCMTIME;

	switch (mode) {
	case S_IFDIR:
		inode->i_private = oe;
		inode->i_op = &ovl_dir_inode_operations;
		inode->i_fop = &ovl_dir_operations;
		break;

	case S_IFLNK:
		inode->i_op = &ovl_symlink_inode_operations;
		break;

	case S_IFREG:
	case S_IFSOCK:
	case S_IFBLK:
	case S_IFCHR:
	case S_IFIFO:
		inode->i_op = &ovl_file_inode_operations;
		break;

	default:
		WARN(1, "illegal file type: %i\n", mode);
		iput(inode);
		inode = NULL;
	}

	return inode;
}
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/xattr.h>
	13	#include "overlayfs.h"
	14
0f7ff2da	15	static int ovl_copy_up_truncate(struct dentry *dentry)
e9be9d5e MS	16	{
	17	int err;
	18	struct dentry *parent;
	19	struct kstat stat;
	20	struct path lowerpath;
	21
	22	parent = dget_parent(dentry);
	23	err = ovl_copy_up(parent);
	24	if (err)
	25	goto out_dput_parent;
	26
	27	ovl_path_lower(dentry, &lowerpath);
	28	err = vfs_getattr(&lowerpath, &stat);
	29	if (err)
	30	goto out_dput_parent;
	31
0f7ff2da AV	32	stat.size = 0;
0f7ff2da AV	33	err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
e9be9d5e MS	34
	35	out_dput_parent:
	36	dput(parent);
	37	return err;
	38	}
	39
	40	int ovl_setattr(struct dentry dentry, struct iattr attr)
	41	{
	42	int err;
	43	struct dentry *upperdentry;
	44
cf9a6784 MS	45	/*
	46	* Check for permissions before trying to copy-up. This is redundant
	47	* since it will be rechecked later by ->setattr() on upper dentry. But
	48	* without this, copy-up can be triggered by just about anybody.
	49	*
	50	* We don't initialize inode->size, which just means that
	51	* inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not
	52	* check for a swapfile (which this won't be anyway).
	53	*/
	54	err = inode_change_ok(dentry->d_inode, attr);
	55	if (err)
	56	return err;
	57
e9be9d5e MS	58	err = ovl_want_write(dentry);
	59	if (err)
	60	goto out;
	61
acff81ec MS	62	err = ovl_copy_up(dentry);
	63	if (!err) {
	64	upperdentry = ovl_dentry_upper(dentry);
	65
5955102c	66	inode_lock(upperdentry->d_inode);
e9be9d5e	67	err = notify_change(upperdentry, attr, NULL);
5955102c	68	inode_unlock(upperdentry->d_inode);
e9be9d5e MS	69	}
	70	ovl_drop_write(dentry);
	71	out:
	72	return err;
	73	}
	74
	75	static int ovl_getattr(struct vfsmount mnt, struct dentry dentry,
	76	struct kstat *stat)
	77	{
	78	struct path realpath;
	79
	80	ovl_path_real(dentry, &realpath);
	81	return vfs_getattr(&realpath, stat);
	82	}
	83
	84	int ovl_permission(struct inode *inode, int mask)
	85	{
	86	struct ovl_entry *oe;
	87	struct dentry *alias = NULL;
	88	struct inode *realinode;
	89	struct dentry *realdentry;
	90	bool is_upper;
	91	int err;
	92
	93	if (S_ISDIR(inode->i_mode)) {
	94	oe = inode->i_private;
	95	} else if (mask & MAY_NOT_BLOCK) {
	96	return -ECHILD;
	97	} else {
	98	/*
	99	* For non-directories find an alias and get the info
	100	* from there.
	101	*/
	102	alias = d_find_any_alias(inode);
	103	if (WARN_ON(!alias))
	104	return -ENOENT;
	105
	106	oe = alias->d_fsdata;
	107	}
	108
	109	realdentry = ovl_entry_real(oe, &is_upper);
	110
8d3095f4 MS	111	if (ovl_is_default_permissions(inode)) {
	112	struct kstat stat;
	113	struct path realpath = { .dentry = realdentry };
	114
	115	if (mask & MAY_NOT_BLOCK)
	116	return -ECHILD;
	117
	118	realpath.mnt = ovl_entry_mnt_real(oe, inode, is_upper);
	119
	120	err = vfs_getattr(&realpath, &stat);
	121	if (err)
	122	return err;
	123
	124	if ((stat.mode ^ inode->i_mode) & S_IFMT)
	125	return -ESTALE;
	126
	127	inode->i_mode = stat.mode;
	128	inode->i_uid = stat.uid;
	129	inode->i_gid = stat.gid;
	130
	131	return generic_permission(inode, mask);
	132	}
	133
e9be9d5e MS	134	/* Careful in RCU walk mode */
	135	realinode = ACCESS_ONCE(realdentry->d_inode);
	136	if (!realinode) {
	137	WARN_ON(!(mask & MAY_NOT_BLOCK));
	138	err = -ENOENT;
	139	goto out_dput;
	140	}
	141
	142	if (mask & MAY_WRITE) {
	143	umode_t mode = realinode->i_mode;
	144
	145	/*
	146	* Writes will always be redirected to upper layer, so
	147	* ignore lower layer being read-only.
	148	*
	149	* If the overlay itself is read-only then proceed
	150	* with the permission check, don't return EROFS.
	151	* This will only happen if this is the lower layer of
	152	* another overlayfs.
	153	*
	154	* If upper fs becomes read-only after the overlay was
	155	* constructed return EROFS to prevent modification of
	156	* upper layer.
	157	*/
	158	err = -EROFS;
	159	if (is_upper && !IS_RDONLY(inode) && IS_RDONLY(realinode) &&
	160	(S_ISREG(mode) \|\| S_ISDIR(mode) \|\| S_ISLNK(mode)))
	161	goto out_dput;
	162	}
	163
	164	err = __inode_permission(realinode, mask);
	165	out_dput:
	166	dput(alias);
	167	return err;
	168	}
	169
6b255391	170	static const char ovl_get_link(struct dentry dentry,
fceef393 AV	171	struct inode *inode,
fceef393 AV	172	struct delayed_call *done)
e9be9d5e	173	{
e9be9d5e MS	174	struct dentry *realdentry;
	175	struct inode *realinode;
	176
6b255391 AV	177	if (!dentry)
	178	return ERR_PTR(-ECHILD);
	179
e9be9d5e MS	180	realdentry = ovl_dentry_real(dentry);
	181	realinode = realdentry->d_inode;
	182
6b255391	183	if (WARN_ON(!realinode->i_op->get_link))
e9be9d5e MS	184	return ERR_PTR(-EPERM);
e9be9d5e MS	185
fceef393	186	return realinode->i_op->get_link(realdentry, realinode, done);
e9be9d5e MS	187	}
	188
	189	static int ovl_readlink(struct dentry dentry, char __user buf, int bufsiz)
	190	{
	191	struct path realpath;
	192	struct inode *realinode;
	193
	194	ovl_path_real(dentry, &realpath);
	195	realinode = realpath.dentry->d_inode;
	196
	197	if (!realinode->i_op->readlink)
	198	return -EINVAL;
	199
	200	touch_atime(&realpath);
	201
	202	return realinode->i_op->readlink(realpath.dentry, buf, bufsiz);
	203	}
	204
	205
	206	static bool ovl_is_private_xattr(const char *name)
	207	{
cead89bb	208	return strncmp(name, OVL_XATTR_PRE_NAME, OVL_XATTR_PRE_LEN) == 0;
e9be9d5e MS	209	}
	210
	211	int ovl_setxattr(struct dentry dentry, const char name,
	212	const void *value, size_t size, int flags)
	213	{
	214	int err;
	215	struct dentry *upperdentry;
	216
	217	err = ovl_want_write(dentry);
	218	if (err)
	219	goto out;
	220
	221	err = -EPERM;
	222	if (ovl_is_private_xattr(name))
	223	goto out_drop_write;
	224
	225	err = ovl_copy_up(dentry);
	226	if (err)
	227	goto out_drop_write;
	228
	229	upperdentry = ovl_dentry_upper(dentry);
	230	err = vfs_setxattr(upperdentry, name, value, size, flags);
	231
	232	out_drop_write:
	233	ovl_drop_write(dentry);
	234	out:
	235	return err;
	236	}
	237
52148463 MS	238	static bool ovl_need_xattr_filter(struct dentry *dentry,
	239	enum ovl_path_type type)
	240	{
1afaba1e MS	241	if ((type & (__OVL_PATH_PURE \| __OVL_PATH_UPPER)) == __OVL_PATH_UPPER)
	242	return S_ISDIR(dentry->d_inode->i_mode);
	243	else
	244	return false;
52148463 MS	245	}
52148463 MS	246
e9be9d5e MS	247	ssize_t ovl_getxattr(struct dentry dentry, const char name,
	248	void *value, size_t size)
	249	{
52148463 MS	250	struct path realpath;
	251	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
	252
	253	if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
e9be9d5e MS	254	return -ENODATA;
e9be9d5e MS	255
52148463	256	return vfs_getxattr(realpath.dentry, name, value, size);
e9be9d5e MS	257	}
	258
	259	ssize_t ovl_listxattr(struct dentry dentry, char list, size_t size)
	260	{
52148463 MS	261	struct path realpath;
52148463 MS	262	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
e9be9d5e MS	263	ssize_t res;
	264	int off;
	265
52148463	266	res = vfs_listxattr(realpath.dentry, list, size);
e9be9d5e MS	267	if (res <= 0 \|\| size == 0)
	268	return res;
	269
52148463	270	if (!ovl_need_xattr_filter(dentry, type))
e9be9d5e MS	271	return res;
	272
	273	/* filter out private xattrs */
	274	for (off = 0; off < res;) {
	275	char *s = list + off;
	276	size_t slen = strlen(s) + 1;
	277
	278	BUG_ON(off + slen > res);
	279
	280	if (ovl_is_private_xattr(s)) {
	281	res -= slen;
	282	memmove(s, s + slen, res - off);
	283	} else {
	284	off += slen;
	285	}
	286	}
	287
	288	return res;
	289	}
	290
	291	int ovl_removexattr(struct dentry dentry, const char name)
	292	{
	293	int err;
	294	struct path realpath;
52148463	295	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
e9be9d5e MS	296
	297	err = ovl_want_write(dentry);
	298	if (err)
	299	goto out;
	300
52148463 MS	301	err = -ENODATA;
52148463 MS	302	if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
e9be9d5e MS	303	goto out_drop_write;
e9be9d5e MS	304
1afaba1e	305	if (!OVL_TYPE_UPPER(type)) {
e9be9d5e MS	306	err = vfs_getxattr(realpath.dentry, name, NULL, 0);
	307	if (err < 0)
	308	goto out_drop_write;
	309
	310	err = ovl_copy_up(dentry);
	311	if (err)
	312	goto out_drop_write;
	313
	314	ovl_path_upper(dentry, &realpath);
	315	}
	316
	317	err = vfs_removexattr(realpath.dentry, name);
	318	out_drop_write:
	319	ovl_drop_write(dentry);
	320	out:
	321	return err;
	322	}
	323
	324	static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,
	325	struct dentry *realdentry)
	326	{
1afaba1e	327	if (OVL_TYPE_UPPER(type))
e9be9d5e MS	328	return false;
	329
	330	if (special_file(realdentry->d_inode->i_mode))
	331	return false;
	332
	333	if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC))
	334	return false;
	335
	336	return true;
	337	}
	338
4bacc9c9	339	struct inode ovl_d_select_inode(struct dentry dentry, unsigned file_flags)
e9be9d5e MS	340	{
	341	int err;
	342	struct path realpath;
	343	enum ovl_path_type type;
e9be9d5e	344
9391dd00 AV	345	if (d_is_dir(dentry))
	346	return d_backing_inode(dentry);
	347
e9be9d5e	348	type = ovl_path_real(dentry, &realpath);
4bacc9c9	349	if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
e9be9d5e MS	350	err = ovl_want_write(dentry);
e9be9d5e MS	351	if (err)
4bacc9c9	352	return ERR_PTR(err);
e9be9d5e	353
4bacc9c9	354	if (file_flags & O_TRUNC)
0f7ff2da	355	err = ovl_copy_up_truncate(dentry);
e9be9d5e MS	356	else
e9be9d5e MS	357	err = ovl_copy_up(dentry);
f25801ee	358	ovl_drop_write(dentry);
e9be9d5e	359	if (err)
4bacc9c9	360	return ERR_PTR(err);
e9be9d5e MS	361
	362	ovl_path_upper(dentry, &realpath);
	363	}
	364
1c8a47df MS	365	if (realpath.dentry->d_flags & DCACHE_OP_SELECT_INODE)
	366	return realpath.dentry->d_op->d_select_inode(realpath.dentry, file_flags);
	367
4bacc9c9	368	return d_backing_inode(realpath.dentry);
e9be9d5e MS	369	}
	370
	371	static const struct inode_operations ovl_file_inode_operations = {
	372	.setattr = ovl_setattr,
	373	.permission = ovl_permission,
	374	.getattr = ovl_getattr,
	375	.setxattr = ovl_setxattr,
	376	.getxattr = ovl_getxattr,
	377	.listxattr = ovl_listxattr,
	378	.removexattr = ovl_removexattr,
e9be9d5e MS	379	};
	380
	381	static const struct inode_operations ovl_symlink_inode_operations = {
	382	.setattr = ovl_setattr,
6b255391	383	.get_link = ovl_get_link,
e9be9d5e MS	384	.readlink = ovl_readlink,
	385	.getattr = ovl_getattr,
	386	.setxattr = ovl_setxattr,
	387	.getxattr = ovl_getxattr,
	388	.listxattr = ovl_listxattr,
	389	.removexattr = ovl_removexattr,
	390	};
	391
	392	struct inode ovl_new_inode(struct super_block sb, umode_t mode,
	393	struct ovl_entry *oe)
	394	{
	395	struct inode *inode;
	396
	397	inode = new_inode(sb);
	398	if (!inode)
	399	return NULL;
	400
	401	mode &= S_IFMT;
	402
	403	inode->i_ino = get_next_ino();
	404	inode->i_mode = mode;
	405	inode->i_flags \|= S_NOATIME \| S_NOCMTIME;
	406
	407	switch (mode) {
	408	case S_IFDIR:
	409	inode->i_private = oe;
	410	inode->i_op = &ovl_dir_inode_operations;
	411	inode->i_fop = &ovl_dir_operations;
	412	break;
	413
	414	case S_IFLNK:
	415	inode->i_op = &ovl_symlink_inode_operations;
	416	break;
	417
	418	case S_IFREG:
	419	case S_IFSOCK:
	420	case S_IFBLK:
	421	case S_IFCHR:
	422	case S_IFIFO:
	423	inode->i_op = &ovl_file_inode_operations;
	424	break;
	425
	426	default:
	427	WARN(1, "illegal file type: %i\n", mode);
	428	iput(inode);
	429	inode = NULL;
	430	}
	431
	432	return inode;
e9be9d5e	433	}