[mirror_ubuntu-zesty-kernel.git] / fs / overlayfs / overlayfs.h

/*
 *
 * 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/kernel.h>

struct ovl_entry;

enum ovl_path_type {
	__OVL_PATH_PURE		= (1 << 0),
	__OVL_PATH_UPPER	= (1 << 1),
	__OVL_PATH_MERGE	= (1 << 2),
};

#define OVL_TYPE_UPPER(type)	((type) & __OVL_PATH_UPPER)
#define OVL_TYPE_MERGE(type)	((type) & __OVL_PATH_MERGE)
#define OVL_TYPE_PURE_UPPER(type) ((type) & __OVL_PATH_PURE)
#define OVL_TYPE_MERGE_OR_LOWER(type) \
	(OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type))


#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"

#define OVL_ISUPPER_MASK 1UL

static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
{
	int err = vfs_rmdir(dir, dentry);
	pr_debug("rmdir(%pd2) = %i\n", dentry, err);
	return err;
}

static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
{
	int err = vfs_unlink(dir, dentry, NULL);
	pr_debug("unlink(%pd2) = %i\n", dentry, err);
	return err;
}

static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
			      struct dentry *new_dentry, bool debug)
{
	int err = vfs_link(old_dentry, dir, new_dentry, NULL);
	if (debug) {
		pr_debug("link(%pd2, %pd2) = %i\n",
			 old_dentry, new_dentry, err);
	}
	return err;
}

static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
			     umode_t mode, bool debug)
{
	int err = vfs_create(dir, dentry, mode, true);
	if (debug)
		pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
	return err;
}

static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
			       umode_t mode, bool debug)
{
	int err = vfs_mkdir(dir, dentry, mode);
	if (debug)
		pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
	return err;
}

static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
			       umode_t mode, dev_t dev, bool debug)
{
	int err = vfs_mknod(dir, dentry, mode, dev);
	if (debug) {
		pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n",
			 dentry, mode, dev, err);
	}
	return err;
}

static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
				 const char *oldname, bool debug)
{
	int err = vfs_symlink(dir, dentry, oldname);
	if (debug)
		pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
	return err;
}

static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
				  const void *value, size_t size, int flags)
{
	struct inode *inode = dentry->d_inode;
	int err;

	inode_lock(inode);
	err = __vfs_setxattr_noperm(dentry, name, value, size, flags);
	inode_unlock(inode);

	pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
		 dentry, name, (int) size, (char *) value, flags, err);
	return err;
}

static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
{
	struct inode *inode = dentry->d_inode;
	int err;

	inode_lock(inode);
	err = __vfs_removexattr_noperm(dentry, name);
	inode_unlock(inode);

	pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
	return err;
}

static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
				struct inode *newdir, struct dentry *newdentry,
				unsigned int flags)
{
	int err;

	pr_debug("rename(%pd2, %pd2, 0x%x)\n",
		 olddentry, newdentry, flags);

	err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);

	if (err) {
		pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
			 olddentry, newdentry, err);
	}
	return err;
}

static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
{
	int err = vfs_whiteout(dir, dentry);
	pr_debug("whiteout(%pd2) = %i\n", dentry, err);
	return err;
}

static inline struct inode *ovl_inode_real(struct inode *inode, bool *is_upper)
{
	unsigned long x = (unsigned long) READ_ONCE(inode->i_private);

	if (is_upper)
		*is_upper = x & OVL_ISUPPER_MASK;

	return (struct inode *) (x & ~OVL_ISUPPER_MASK);
}

enum ovl_path_type ovl_path_type(struct dentry *dentry);
u64 ovl_dentry_version_get(struct dentry *dentry);
void ovl_dentry_version_inc(struct dentry *dentry);
void ovl_path_upper(struct dentry *dentry, struct path *path);
void ovl_path_lower(struct dentry *dentry, struct path *path);
enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
struct dentry *ovl_dentry_upper(struct dentry *dentry);
struct dentry *ovl_dentry_lower(struct dentry *dentry);
struct dentry *ovl_dentry_real(struct dentry *dentry);
struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode,
				    bool is_upper);
struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
struct dentry *ovl_workdir(struct dentry *dentry);
int ovl_want_write(struct dentry *dentry);
void ovl_drop_write(struct dentry *dentry);
bool ovl_dentry_is_opaque(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque);
bool ovl_is_whiteout(struct dentry *dentry);
const struct cred *ovl_override_creds(struct super_block *sb);
void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
void ovl_inode_update(struct inode *inode, struct inode *upperinode);
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
			  unsigned int flags);
struct file *ovl_path_open(struct path *path, int flags);

struct dentry *ovl_upper_create(struct dentry *upperdir, struct dentry *dentry,
				struct kstat *stat, const char *link);

/* readdir.c */
extern const struct file_operations ovl_dir_operations;
int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
void ovl_cache_free(struct list_head *list);
int ovl_check_d_type_supported(struct path *realpath);
void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
			 struct dentry *dentry, int level);

/* inode.c */
int ovl_setattr(struct dentry *dentry, struct iattr *attr);
int ovl_permission(struct inode *inode, int mask);
int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
		  size_t size, int flags);
int ovl_xattr_get(struct dentry *dentry, const char *name,
		  void *value, size_t size);
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
struct posix_acl *ovl_get_acl(struct inode *inode, int type);
int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
bool ovl_is_private_xattr(const char *name);

struct inode *ovl_new_inode(struct super_block *sb, umode_t mode);
struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode);
static inline void ovl_copyattr(struct inode *from, struct inode *to)
{
	to->i_uid = from->i_uid;
	to->i_gid = from->i_gid;
	to->i_mode = from->i_mode;
	to->i_atime = from->i_atime;
	to->i_mtime = from->i_mtime;
	to->i_ctime = from->i_ctime;
}

/* dir.c */
extern const struct inode_operations ovl_dir_inode_operations;
struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry);
int ovl_create_real(struct inode *dir, struct dentry *newdentry,
		    struct kstat *stat, const char *link,
		    struct dentry *hardlink, bool debug);
void ovl_cleanup(struct inode *dir, struct dentry *dentry);

/* copy_up.c */
int ovl_copy_up(struct dentry *dentry);
int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
		    struct path *lowerpath, struct kstat *stat);
int ovl_copy_xattr(struct dentry *old, struct dentry *new);
int ovl_set_attr(struct dentry *upper, struct kstat *stat);
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/kernel.h>
	11
	12	struct ovl_entry;
	13
	14	enum ovl_path_type {
1afaba1e MS	15	__OVL_PATH_PURE = (1 << 0),
	16	__OVL_PATH_UPPER = (1 << 1),
	17	__OVL_PATH_MERGE = (1 << 2),
e9be9d5e MS	18	};
e9be9d5e MS	19
1afaba1e MS	20	#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
	21	#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
	22	#define OVL_TYPE_PURE_UPPER(type) ((type) & __OVL_PATH_PURE)
	23	#define OVL_TYPE_MERGE_OR_LOWER(type) \
	24	(OVL_TYPE_MERGE(type) \|\| !OVL_TYPE_UPPER(type))
	25
d837a49b	26
fe2b7595 AG	27	#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
fe2b7595 AG	28	#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
e9be9d5e	29
39b681f8 MS	30	#define OVL_ISUPPER_MASK 1UL
39b681f8 MS	31
e9be9d5e MS	32	static inline int ovl_do_rmdir(struct inode dir, struct dentry dentry)
	33	{
	34	int err = vfs_rmdir(dir, dentry);
	35	pr_debug("rmdir(%pd2) = %i\n", dentry, err);
	36	return err;
	37	}
	38
	39	static inline int ovl_do_unlink(struct inode dir, struct dentry dentry)
	40	{
	41	int err = vfs_unlink(dir, dentry, NULL);
	42	pr_debug("unlink(%pd2) = %i\n", dentry, err);
	43	return err;
	44	}
	45
	46	static inline int ovl_do_link(struct dentry old_dentry, struct inode dir,
	47	struct dentry *new_dentry, bool debug)
	48	{
	49	int err = vfs_link(old_dentry, dir, new_dentry, NULL);
	50	if (debug) {
	51	pr_debug("link(%pd2, %pd2) = %i\n",
	52	old_dentry, new_dentry, err);
	53	}
	54	return err;
	55	}
	56
	57	static inline int ovl_do_create(struct inode dir, struct dentry dentry,
	58	umode_t mode, bool debug)
	59	{
	60	int err = vfs_create(dir, dentry, mode, true);
	61	if (debug)
	62	pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
	63	return err;
	64	}
	65
	66	static inline int ovl_do_mkdir(struct inode dir, struct dentry dentry,
	67	umode_t mode, bool debug)
	68	{
	69	int err = vfs_mkdir(dir, dentry, mode);
	70	if (debug)
	71	pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
	72	return err;
	73	}
	74
	75	static inline int ovl_do_mknod(struct inode dir, struct dentry dentry,
	76	umode_t mode, dev_t dev, bool debug)
	77	{
	78	int err = vfs_mknod(dir, dentry, mode, dev);
	79	if (debug) {
	80	pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n",
	81	dentry, mode, dev, err);
	82	}
	83	return err;
	84	}
	85
	86	static inline int ovl_do_symlink(struct inode dir, struct dentry dentry,
	87	const char *oldname, bool debug)
	88	{
	89	int err = vfs_symlink(dir, dentry, oldname);
	90	if (debug)
	91	pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
	92	return err;
	93	}
	94
	95	static inline int ovl_do_setxattr(struct dentry dentry, const char name,
96	const void *value, size_t size, int flags)
97	{
acb0bcdb SF	98	struct inode *inode = dentry->d_inode;
	99	int err;
	100
	101	inode_lock(inode);
	102	err = __vfs_setxattr_noperm(dentry, name, value, size, flags);
	103	inode_unlock(inode);
	104
e9be9d5e MS	105	pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
	106	dentry, name, (int) size, (char *) value, flags, err);
	107	return err;
	108	}
	109
	110	static inline int ovl_do_removexattr(struct dentry dentry, const char name)
	111	{
acb0bcdb SF	112	struct inode *inode = dentry->d_inode;
	113	int err;
	114
	115	inode_lock(inode);
	116	err = __vfs_removexattr_noperm(dentry, name);
	117	inode_unlock(inode);
	118
e9be9d5e MS	119	pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
	120	return err;
	121	}
	122
	123	static inline int ovl_do_rename(struct inode olddir, struct dentry olddentry,
	124	struct inode newdir, struct dentry newdentry,
	125	unsigned int flags)
	126	{
	127	int err;
	128
2773bf00	129	pr_debug("rename(%pd2, %pd2, 0x%x)\n",
e9be9d5e MS	130	olddentry, newdentry, flags);
	131
	132	err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
	133
	134	if (err) {
2773bf00	135	pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
e9be9d5e MS	136	olddentry, newdentry, err);
	137	}
	138	return err;
	139	}
	140
	141	static inline int ovl_do_whiteout(struct inode dir, struct dentry dentry)
	142	{
	143	int err = vfs_whiteout(dir, dentry);
	144	pr_debug("whiteout(%pd2) = %i\n", dentry, err);
	145	return err;
	146	}
	147
39b681f8 MS	148	static inline struct inode ovl_inode_real(struct inode inode, bool *is_upper)
	149	{
	150	unsigned long x = (unsigned long) READ_ONCE(inode->i_private);
	151
	152	if (is_upper)
	153	*is_upper = x & OVL_ISUPPER_MASK;
	154
	155	return (struct inode *) (x & ~OVL_ISUPPER_MASK);
	156	}
	157
e9be9d5e MS	158	enum ovl_path_type ovl_path_type(struct dentry *dentry);
	159	u64 ovl_dentry_version_get(struct dentry *dentry);
	160	void ovl_dentry_version_inc(struct dentry *dentry);
	161	void ovl_path_upper(struct dentry dentry, struct path path);
	162	void ovl_path_lower(struct dentry dentry, struct path path);
	163	enum ovl_path_type ovl_path_real(struct dentry dentry, struct path path);
5ef88da5	164	int ovl_path_next(int idx, struct dentry dentry, struct path path);
e9be9d5e MS	165	struct dentry ovl_dentry_upper(struct dentry dentry);
	166	struct dentry ovl_dentry_lower(struct dentry dentry);
	167	struct dentry ovl_dentry_real(struct dentry dentry);
8d3095f4 MS	168	struct vfsmount ovl_entry_mnt_real(struct ovl_entry oe, struct inode *inode,
8d3095f4 MS	169	bool is_upper);
e9be9d5e MS	170	struct ovl_dir_cache ovl_dir_cache(struct dentry dentry);
	171	void ovl_set_dir_cache(struct dentry dentry, struct ovl_dir_cache cache);
	172	struct dentry ovl_workdir(struct dentry dentry);
	173	int ovl_want_write(struct dentry *dentry);
	174	void ovl_drop_write(struct dentry *dentry);
	175	bool ovl_dentry_is_opaque(struct dentry *dentry);
	176	void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque);
	177	bool ovl_is_whiteout(struct dentry *dentry);
3fe6e52f	178	const struct cred ovl_override_creds(struct super_block sb);
e9be9d5e	179	void ovl_dentry_update(struct dentry dentry, struct dentry upperdentry);
39b681f8	180	void ovl_inode_update(struct inode inode, struct inode upperinode);
e9be9d5e MS	181	struct dentry ovl_lookup(struct inode dir, struct dentry *dentry,
	182	unsigned int flags);
	183	struct file ovl_path_open(struct path path, int flags);
	184
	185	struct dentry ovl_upper_create(struct dentry upperdir, struct dentry *dentry,
	186	struct kstat stat, const char link);
	187
	188	/* readdir.c */
	189	extern const struct file_operations ovl_dir_operations;
	190	int ovl_check_empty_dir(struct dentry dentry, struct list_head list);
	191	void ovl_cleanup_whiteouts(struct dentry upper, struct list_head list);
	192	void ovl_cache_free(struct list_head *list);
45aebeaf	193	int ovl_check_d_type_supported(struct path *realpath);
eea2fb48 MS	194	void ovl_workdir_cleanup(struct inode dir, struct vfsmount mnt,
eea2fb48 MS	195	struct dentry *dentry, int level);
e9be9d5e MS	196
	197	/* inode.c */
	198	int ovl_setattr(struct dentry dentry, struct iattr attr);
	199	int ovl_permission(struct inode *inode, int mask);
0e585ccc AG	200	int ovl_xattr_set(struct dentry dentry, const char name, const void *value,
0e585ccc AG	201	size_t size, int flags);
0eb45fc3 AG	202	int ovl_xattr_get(struct dentry dentry, const char name,
0eb45fc3 AG	203	void *value, size_t size);
e9be9d5e	204	ssize_t ovl_listxattr(struct dentry dentry, char list, size_t size);
39a25b2b	205	struct posix_acl ovl_get_acl(struct inode inode, int type);
2d902671	206	int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
d719e8f2	207	int ovl_update_time(struct inode inode, struct timespec ts, int flags);
0956254a	208	bool ovl_is_private_xattr(const char *name);
e9be9d5e	209
39b681f8	210	struct inode ovl_new_inode(struct super_block sb, umode_t mode);
51f7e52d	211	struct inode ovl_get_inode(struct super_block sb, struct inode *realinode);
e9be9d5e MS	212	static inline void ovl_copyattr(struct inode from, struct inode to)
	213	{
	214	to->i_uid = from->i_uid;
	215	to->i_gid = from->i_gid;
07a2daab	216	to->i_mode = from->i_mode;
d719e8f2 MS	217	to->i_atime = from->i_atime;
	218	to->i_mtime = from->i_mtime;
	219	to->i_ctime = from->i_ctime;
e9be9d5e MS	220	}
	221
	222	/* dir.c */
	223	extern const struct inode_operations ovl_dir_inode_operations;
	224	struct dentry ovl_lookup_temp(struct dentry workdir, struct dentry *dentry);
	225	int ovl_create_real(struct inode dir, struct dentry newdentry,
	226	struct kstat stat, const char link,
	227	struct dentry *hardlink, bool debug);
	228	void ovl_cleanup(struct inode dir, struct dentry dentry);
	229
	230	/* copy_up.c */
	231	int ovl_copy_up(struct dentry *dentry);
	232	int ovl_copy_up_one(struct dentry parent, struct dentry dentry,
0f7ff2da	233	struct path lowerpath, struct kstat stat);
e9be9d5e MS	234	int ovl_copy_xattr(struct dentry old, struct dentry new);
e9be9d5e MS	235	int ovl_set_attr(struct dentry upper, struct kstat stat);