[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>

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

#define OVL_TYPE_UPPER(type)	((type) & __OVL_PATH_UPPER)
#define OVL_TYPE_MERGE(type)	((type) & __OVL_PATH_MERGE)

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

#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);
}

/* util.c */
int ovl_want_write(struct dentry *dentry);
void ovl_drop_write(struct dentry *dentry);
struct dentry *ovl_workdir(struct dentry *dentry);
const struct cred *ovl_override_creds(struct super_block *sb);
struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
bool ovl_dentry_remote(struct dentry *dentry);
bool ovl_dentry_weird(struct dentry *dentry);
enum ovl_path_type ovl_path_type(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);
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 ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
bool ovl_dentry_is_opaque(struct dentry *dentry);
bool ovl_dentry_is_whiteout(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry);
bool ovl_redirect_dir(struct super_block *sb);
void ovl_clear_redirect_dir(struct super_block *sb);
const char *ovl_dentry_get_redirect(struct dentry *dentry);
void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
void ovl_inode_init(struct inode *inode, struct inode *realinode,
		    bool is_upper);
void ovl_inode_update(struct inode *inode, struct inode *upperinode);
void ovl_dentry_version_inc(struct dentry *dentry);
u64 ovl_dentry_version_get(struct dentry *dentry);
bool ovl_is_whiteout(struct dentry *dentry);
struct file *ovl_path_open(struct path *path, int flags);

/* namei.c */
int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
bool ovl_lower_positive(struct dentry *dentry);

/* 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, dev_t rdev);
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);
struct cattr {
	dev_t rdev;
	umode_t mode;
	const char *link;
};
int ovl_create_real(struct inode *dir, struct dentry *newdentry,
		    struct cattr *attr,
		    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_flags(struct dentry *dentry, int flags);
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
e9be9d5e	12	enum ovl_path_type {
38e813db MS	13	__OVL_PATH_UPPER = (1 << 0),
38e813db MS	14	__OVL_PATH_MERGE = (1 << 1),
e9be9d5e MS	15	};
e9be9d5e MS	16
1afaba1e MS	17	#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
1afaba1e MS	18	#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
d837a49b	19
fe2b7595 AG	20	#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
fe2b7595 AG	21	#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
02b69b28	22	#define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect"
e9be9d5e	23
39b681f8 MS	24	#define OVL_ISUPPER_MASK 1UL
39b681f8 MS	25
e9be9d5e MS	26	static inline int ovl_do_rmdir(struct inode dir, struct dentry dentry)
	27	{
	28	int err = vfs_rmdir(dir, dentry);
	29	pr_debug("rmdir(%pd2) = %i\n", dentry, err);
	30	return err;
	31	}
	32
	33	static inline int ovl_do_unlink(struct inode dir, struct dentry dentry)
	34	{
	35	int err = vfs_unlink(dir, dentry, NULL);
	36	pr_debug("unlink(%pd2) = %i\n", dentry, err);
	37	return err;
	38	}
	39
	40	static inline int ovl_do_link(struct dentry old_dentry, struct inode dir,
	41	struct dentry *new_dentry, bool debug)
	42	{
	43	int err = vfs_link(old_dentry, dir, new_dentry, NULL);
	44	if (debug) {
	45	pr_debug("link(%pd2, %pd2) = %i\n",
	46	old_dentry, new_dentry, err);
	47	}
	48	return err;
	49	}
	50
	51	static inline int ovl_do_create(struct inode dir, struct dentry dentry,
	52	umode_t mode, bool debug)
	53	{
	54	int err = vfs_create(dir, dentry, mode, true);
	55	if (debug)
	56	pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
	57	return err;
	58	}
	59
	60	static inline int ovl_do_mkdir(struct inode dir, struct dentry dentry,
	61	umode_t mode, bool debug)
	62	{
	63	int err = vfs_mkdir(dir, dentry, mode);
	64	if (debug)
	65	pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
	66	return err;
	67	}
	68
	69	static inline int ovl_do_mknod(struct inode dir, struct dentry dentry,
	70	umode_t mode, dev_t dev, bool debug)
	71	{
	72	int err = vfs_mknod(dir, dentry, mode, dev);
	73	if (debug) {
	74	pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n",
	75	dentry, mode, dev, err);
	76	}
	77	return err;
	78	}
	79
	80	static inline int ovl_do_symlink(struct inode dir, struct dentry dentry,
	81	const char *oldname, bool debug)
	82	{
	83	int err = vfs_symlink(dir, dentry, oldname);
	84	if (debug)
	85	pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
	86	return err;
	87	}
	88
	89	static inline int ovl_do_setxattr(struct dentry dentry, const char name,
90	const void *value, size_t size, int flags)
91	{
25b33138 SF	92	struct inode *inode = dentry->d_inode;
	93	int err;
	94
	95	inode_lock(inode);
	96	err = __vfs_setxattr_noperm(dentry, name, value, size, flags);
	97	inode_unlock(inode);
	98
e9be9d5e MS	99	pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
	100	dentry, name, (int) size, (char *) value, flags, err);
	101	return err;
	102	}
	103
	104	static inline int ovl_do_removexattr(struct dentry dentry, const char name)
	105	{
25b33138 SF	106	struct inode *inode = dentry->d_inode;
	107	int err;
	108
	109	inode_lock(inode);
	110	err = __vfs_removexattr_noperm(dentry, name);
	111	inode_unlock(inode);
	112
e9be9d5e MS	113	pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
	114	return err;
	115	}
	116
	117	static inline int ovl_do_rename(struct inode olddir, struct dentry olddentry,
	118	struct inode newdir, struct dentry newdentry,
	119	unsigned int flags)
	120	{
	121	int err;
	122
2773bf00	123	pr_debug("rename(%pd2, %pd2, 0x%x)\n",
e9be9d5e MS	124	olddentry, newdentry, flags);
	125
	126	err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
	127
	128	if (err) {
2773bf00	129	pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
e9be9d5e MS	130	olddentry, newdentry, err);
	131	}
	132	return err;
	133	}
	134
	135	static inline int ovl_do_whiteout(struct inode dir, struct dentry dentry)
	136	{
	137	int err = vfs_whiteout(dir, dentry);
	138	pr_debug("whiteout(%pd2) = %i\n", dentry, err);
	139	return err;
	140	}
	141
39b681f8 MS	142	static inline struct inode ovl_inode_real(struct inode inode, bool *is_upper)
	143	{
	144	unsigned long x = (unsigned long) READ_ONCE(inode->i_private);
	145
	146	if (is_upper)
	147	*is_upper = x & OVL_ISUPPER_MASK;
	148
	149	return (struct inode *) (x & ~OVL_ISUPPER_MASK);
	150	}
	151
bbb1e54d MS	152	/* util.c */
	153	int ovl_want_write(struct dentry *dentry);
	154	void ovl_drop_write(struct dentry *dentry);
	155	struct dentry ovl_workdir(struct dentry dentry);
	156	const struct cred ovl_override_creds(struct super_block sb);
	157	struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
	158	bool ovl_dentry_remote(struct dentry *dentry);
	159	bool ovl_dentry_weird(struct dentry *dentry);
e9be9d5e	160	enum ovl_path_type ovl_path_type(struct dentry *dentry);
e9be9d5e MS	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);
	164	struct dentry ovl_dentry_upper(struct dentry dentry);
	165	struct dentry ovl_dentry_lower(struct dentry dentry);
	166	struct dentry ovl_dentry_real(struct dentry dentry);
e9be9d5e MS	167	struct ovl_dir_cache ovl_dir_cache(struct dentry dentry);
e9be9d5e MS	168	void ovl_set_dir_cache(struct dentry dentry, struct ovl_dir_cache cache);
e9be9d5e	169	bool ovl_dentry_is_opaque(struct dentry *dentry);
c412ce49	170	bool ovl_dentry_is_whiteout(struct dentry *dentry);
5cf5b477	171	void ovl_dentry_set_opaque(struct dentry *dentry);
a6c60655 MS	172	bool ovl_redirect_dir(struct super_block *sb);
	173	void ovl_clear_redirect_dir(struct super_block *sb);
	174	const char ovl_dentry_get_redirect(struct dentry dentry);
	175	void ovl_dentry_set_redirect(struct dentry dentry, const char redirect);
e9be9d5e	176	void ovl_dentry_update(struct dentry dentry, struct dentry upperdentry);
bbb1e54d MS	177	void ovl_inode_init(struct inode inode, struct inode realinode,
bbb1e54d MS	178	bool is_upper);
39b681f8	179	void ovl_inode_update(struct inode inode, struct inode upperinode);
bbb1e54d MS	180	void ovl_dentry_version_inc(struct dentry *dentry);
	181	u64 ovl_dentry_version_get(struct dentry *dentry);
	182	bool ovl_is_whiteout(struct dentry *dentry);
e9be9d5e MS	183	struct file ovl_path_open(struct path path, int flags);
e9be9d5e MS	184
bbb1e54d MS	185	/* namei.c */
	186	int ovl_path_next(int idx, struct dentry dentry, struct path path);
	187	struct dentry ovl_lookup(struct inode dir, struct dentry *dentry, unsigned int flags);
	188	bool ovl_lower_positive(struct dentry *dentry);
e9be9d5e MS	189
	190	/* readdir.c */
	191	extern const struct file_operations ovl_dir_operations;
	192	int ovl_check_empty_dir(struct dentry dentry, struct list_head list);
	193	void ovl_cleanup_whiteouts(struct dentry upper, struct list_head list);
	194	void ovl_cache_free(struct list_head *list);
45aebeaf	195	int ovl_check_d_type_supported(struct path *realpath);
eea2fb48 MS	196	void ovl_workdir_cleanup(struct inode dir, struct vfsmount mnt,
eea2fb48 MS	197	struct dentry *dentry, int level);
e9be9d5e MS	198
	199	/* inode.c */
	200	int ovl_setattr(struct dentry dentry, struct iattr attr);
	201	int ovl_permission(struct inode *inode, int mask);
0e585ccc AG	202	int ovl_xattr_set(struct dentry dentry, const char name, const void *value,
0e585ccc AG	203	size_t size, int flags);
0eb45fc3 AG	204	int ovl_xattr_get(struct dentry dentry, const char name,
0eb45fc3 AG	205	void *value, size_t size);
e9be9d5e	206	ssize_t ovl_listxattr(struct dentry dentry, char list, size_t size);
39a25b2b	207	struct posix_acl ovl_get_acl(struct inode inode, int type);
2d902671	208	int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
d719e8f2	209	int ovl_update_time(struct inode inode, struct timespec ts, int flags);
0956254a	210	bool ovl_is_private_xattr(const char *name);
e9be9d5e	211
ca4c8a3a	212	struct inode ovl_new_inode(struct super_block sb, umode_t mode, dev_t rdev);
51f7e52d	213	struct inode ovl_get_inode(struct super_block sb, struct inode *realinode);
e9be9d5e MS	214	static inline void ovl_copyattr(struct inode from, struct inode to)
	215	{
	216	to->i_uid = from->i_uid;
	217	to->i_gid = from->i_gid;
07a2daab	218	to->i_mode = from->i_mode;
d719e8f2 MS	219	to->i_atime = from->i_atime;
	220	to->i_mtime = from->i_mtime;
	221	to->i_ctime = from->i_ctime;
e9be9d5e MS	222	}
	223
	224	/* dir.c */
	225	extern const struct inode_operations ovl_dir_inode_operations;
	226	struct dentry ovl_lookup_temp(struct dentry workdir, struct dentry *dentry);
32a3d848 AV	227	struct cattr {
	228	dev_t rdev;
	229	umode_t mode;
	230	const char *link;
	231	};
e9be9d5e	232	int ovl_create_real(struct inode dir, struct dentry newdentry,
32a3d848	233	struct cattr *attr,
e9be9d5e MS	234	struct dentry *hardlink, bool debug);
	235	void ovl_cleanup(struct inode dir, struct dentry dentry);
	236
	237	/* copy_up.c */
	238	int ovl_copy_up(struct dentry *dentry);
9aba6521	239	int ovl_copy_up_flags(struct dentry *dentry, int flags);
e9be9d5e MS	240	int ovl_copy_xattr(struct dentry old, struct dentry new);
e9be9d5e MS	241	int ovl_set_attr(struct dentry upper, struct kstat stat);