[mirror_ubuntu-artful-kernel.git] / fs / ext4 / xattr.h

/*
  File: fs/ext4/xattr.h

  On-disk format of extended attributes for the ext4 filesystem.

  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
*/

#include <linux/xattr.h>

/* Magic value in attribute blocks */
#define EXT4_XATTR_MAGIC		0xEA020000

/* Maximum number of references to one attribute block */
#define EXT4_XATTR_REFCOUNT_MAX		1024

/* Name indexes */
#define EXT4_XATTR_INDEX_USER			1
#define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS	2
#define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT	3
#define EXT4_XATTR_INDEX_TRUSTED		4
#define	EXT4_XATTR_INDEX_LUSTRE			5
#define EXT4_XATTR_INDEX_SECURITY	        6
#define EXT4_XATTR_INDEX_SYSTEM			7
#define EXT4_XATTR_INDEX_RICHACL		8
#define EXT4_XATTR_INDEX_ENCRYPTION		9
#define EXT4_XATTR_INDEX_HURD			10 /* Reserved for Hurd */

struct ext4_xattr_header {
	__le32	h_magic;	/* magic number for identification */
	__le32	h_refcount;	/* reference count */
	__le32	h_blocks;	/* number of disk blocks used */
	__le32	h_hash;		/* hash value of all attributes */
	__le32	h_checksum;	/* crc32c(uuid+id+xattrblock) */
				/* id = inum if refcount=1, blknum otherwise */
	__u32	h_reserved[3];	/* zero right now */
};

struct ext4_xattr_ibody_header {
	__le32	h_magic;	/* magic number for identification */
};

struct ext4_xattr_entry {
	__u8	e_name_len;	/* length of name */
	__u8	e_name_index;	/* attribute name index */
	__le16	e_value_offs;	/* offset in disk block of value */
	__le32	e_value_inum;	/* inode in which the value is stored */
	__le32	e_value_size;	/* size of attribute value */
	__le32	e_hash;		/* hash value of name and value */
	char	e_name[0];	/* attribute name */
};

#define EXT4_XATTR_PAD_BITS		2
#define EXT4_XATTR_PAD		(1<<EXT4_XATTR_PAD_BITS)
#define EXT4_XATTR_ROUND		(EXT4_XATTR_PAD-1)
#define EXT4_XATTR_LEN(name_len) \
	(((name_len) + EXT4_XATTR_ROUND + \
	sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
#define EXT4_XATTR_NEXT(entry) \
	((struct ext4_xattr_entry *)( \
	 (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
#define EXT4_XATTR_SIZE(size) \
	(((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)

#define IHDR(inode, raw_inode) \
	((struct ext4_xattr_ibody_header *) \
		((void *)raw_inode + \
		EXT4_GOOD_OLD_INODE_SIZE + \
		EXT4_I(inode)->i_extra_isize))
#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))

/*
 * The minimum size of EA value when you start storing it in an external inode
 * size of block - size of header - size of 1 entry - 4 null bytes
*/
#define EXT4_XATTR_MIN_LARGE_EA_SIZE(b)					\
	((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4)

#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
#define BFIRST(bh) ENTRY(BHDR(bh)+1)
#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)

#define EXT4_ZERO_XATTR_VALUE ((void *)-1)

struct ext4_xattr_info {
	const char *name;
	const void *value;
	size_t value_len;
	int name_index;
	int in_inode;
};

struct ext4_xattr_search {
	struct ext4_xattr_entry *first;
	void *base;
	void *end;
	struct ext4_xattr_entry *here;
	int not_found;
};

struct ext4_xattr_ibody_find {
	struct ext4_xattr_search s;
	struct ext4_iloc iloc;
};

struct ext4_xattr_inode_array {
	unsigned int count;		/* # of used items in the array */
	struct inode *inodes[0];
};

extern const struct xattr_handler ext4_xattr_user_handler;
extern const struct xattr_handler ext4_xattr_trusted_handler;
extern const struct xattr_handler ext4_xattr_security_handler;

#define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"

/*
 * The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes.
 * The first is to signal that there the inline xattrs and data are
 * taking up so much space that we might as well not keep trying to
 * expand it.  The second is that xattr_sem is taken for writing, so
 * we shouldn't try to recurse into the inode expansion.  For this
 * second case, we need to make sure that we take save and restore the
 * NO_EXPAND state flag appropriately.
 */
static inline void ext4_write_lock_xattr(struct inode *inode, int *save)
{
	down_write(&EXT4_I(inode)->xattr_sem);
	*save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
}

static inline int ext4_write_trylock_xattr(struct inode *inode, int *save)
{
	if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0)
		return 0;
	*save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
	return 1;
}

static inline void ext4_write_unlock_xattr(struct inode *inode, int *save)
{
	if (*save == 0)
		ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
	up_write(&EXT4_I(inode)->xattr_sem);
}

extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);

extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
				  bool is_create, int *credits);
extern int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
				struct buffer_head *block_bh, size_t value_len,
				bool is_create);

extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
				   struct ext4_xattr_inode_array **array,
				   int extra_credits);
extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);

extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
			    struct ext4_inode *raw_inode, handle_t *handle);

extern const struct xattr_handler *ext4_xattr_handlers[];

extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
				 struct ext4_xattr_ibody_find *is);
extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
				const char *name,
				void *buffer, size_t buffer_size);
extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
				       struct ext4_xattr_info *i,
				       struct ext4_xattr_ibody_find *is);

extern struct mb_cache *ext4_xattr_create_cache(void);
extern void ext4_xattr_destroy_cache(struct mb_cache *);

#ifdef CONFIG_EXT4_FS_SECURITY
extern int ext4_init_security(handle_t *handle, struct inode *inode,
			      struct inode *dir, const struct qstr *qstr);
#else
static inline int ext4_init_security(handle_t *handle, struct inode *inode,
				     struct inode *dir, const struct qstr *qstr)
{
	return 0;
}
#endif

#ifdef CONFIG_LOCKDEP
extern void ext4_xattr_inode_set_class(struct inode *ea_inode);
#else
static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { }
#endif

extern int ext4_get_inode_usage(struct inode *inode, qsize_t *usage);
Commit	Line	Data
ac27a0ec	1	/*
617ba13b	2	File: fs/ext4/xattr.h
ac27a0ec	3
617ba13b	4	On-disk format of extended attributes for the ext4 filesystem.
ac27a0ec DK	5
	6	(C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
	7	*/
	8
	9	#include <linux/xattr.h>
	10
	11	/* Magic value in attribute blocks */
617ba13b	12	#define EXT4_XATTR_MAGIC 0xEA020000
ac27a0ec DK	13
ac27a0ec DK	14	/* Maximum number of references to one attribute block */
617ba13b	15	#define EXT4_XATTR_REFCOUNT_MAX 1024
ac27a0ec DK	16
ac27a0ec DK	17	/* Name indexes */
617ba13b MC	18	#define EXT4_XATTR_INDEX_USER 1
	19	#define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS 2
	20	#define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT 3
	21	#define EXT4_XATTR_INDEX_TRUSTED 4
	22	#define EXT4_XATTR_INDEX_LUSTRE 5
	23	#define EXT4_XATTR_INDEX_SECURITY 6
67cf5b09	24	#define EXT4_XATTR_INDEX_SYSTEM 7
fd03d8da	25	#define EXT4_XATTR_INDEX_RICHACL 8
887e2c45	26	#define EXT4_XATTR_INDEX_ENCRYPTION 9
3980bd3b	27	#define EXT4_XATTR_INDEX_HURD 10 /* Reserved for Hurd */
617ba13b MC	28
617ba13b MC	29	struct ext4_xattr_header {
ac27a0ec DK	30	__le32 h_magic; /* magic number for identification */
	31	__le32 h_refcount; /* reference count */
	32	__le32 h_blocks; /* number of disk blocks used */
	33	__le32 h_hash; /* hash value of all attributes */
e6153918 DW	34	__le32 h_checksum; /* crc32c(uuid+id+xattrblock) */
	35	/* id = inum if refcount=1, blknum otherwise */
	36	__u32 h_reserved[3]; /* zero right now */
ac27a0ec DK	37	};
ac27a0ec DK	38
617ba13b	39	struct ext4_xattr_ibody_header {
ac27a0ec DK	40	__le32 h_magic; /* magic number for identification */
	41	};
	42
617ba13b	43	struct ext4_xattr_entry {
ac27a0ec DK	44	__u8 e_name_len; /* length of name */
	45	__u8 e_name_index; /* attribute name index */
	46	__le16 e_value_offs; /* offset in disk block of value */
e50e5129	47	__le32 e_value_inum; /* inode in which the value is stored */
ac27a0ec DK	48	__le32 e_value_size; /* size of attribute value */
	49	__le32 e_hash; /* hash value of name and value */
	50	char e_name[0]; /* attribute name */
	51	};
	52
617ba13b MC	53	#define EXT4_XATTR_PAD_BITS 2
	54	#define EXT4_XATTR_PAD (1<<EXT4_XATTR_PAD_BITS)
	55	#define EXT4_XATTR_ROUND (EXT4_XATTR_PAD-1)
	56	#define EXT4_XATTR_LEN(name_len) \
	57	(((name_len) + EXT4_XATTR_ROUND + \
	58	sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
	59	#define EXT4_XATTR_NEXT(entry) \
af5bc92d TT	60	((struct ext4_xattr_entry *)( \
af5bc92d TT	61	(char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
617ba13b MC	62	#define EXT4_XATTR_SIZE(size) \
617ba13b MC	63	(((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
ac27a0ec	64
6dd4ee7c KS	65	#define IHDR(inode, raw_inode) \
	66	((struct ext4_xattr_ibody_header *) \
	67	((void *)raw_inode + \
	68	EXT4_GOOD_OLD_INODE_SIZE + \
	69	EXT4_I(inode)->i_extra_isize))
	70	#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
	71
e50e5129 AD	72	/*
	73	* The minimum size of EA value when you start storing it in an external inode
	74	* size of block - size of header - size of 1 entry - 4 null bytes
	75	*/
	76	#define EXT4_XATTR_MIN_LARGE_EA_SIZE(b) \
	77	((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4)
	78
879b3825 TM	79	#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
	80	#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
	81	#define BFIRST(bh) ENTRY(BHDR(bh)+1)
	82	#define IS_LAST_ENTRY(entry) ((__u32 )(entry) == 0)
	83
bd9926e8	84	#define EXT4_ZERO_XATTR_VALUE ((void *)-1)
879b3825 TM	85
879b3825 TM	86	struct ext4_xattr_info {
879b3825 TM	87	const char *name;
	88	const void *value;
	89	size_t value_len;
e50e5129 AD	90	int name_index;
e50e5129 AD	91	int in_inode;
879b3825 TM	92	};
	93
	94	struct ext4_xattr_search {
	95	struct ext4_xattr_entry *first;
	96	void *base;
	97	void *end;
	98	struct ext4_xattr_entry *here;
	99	int not_found;
	100	};
	101
	102	struct ext4_xattr_ibody_find {
	103	struct ext4_xattr_search s;
	104	struct ext4_iloc iloc;
	105	};
	106
b6d9029d TE	107	struct ext4_xattr_inode_array {
	108	unsigned int count; /* # of used items in the array */
	109	struct inode *inodes[0];
	110	};
	111
11e27528 SH	112	extern const struct xattr_handler ext4_xattr_user_handler;
11e27528 SH	113	extern const struct xattr_handler ext4_xattr_trusted_handler;
11e27528	114	extern const struct xattr_handler ext4_xattr_security_handler;
ac27a0ec	115
887e2c45 MH	116	#define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"
887e2c45 MH	117
c755e251 TT	118	/*
	119	* The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes.
	120	* The first is to signal that there the inline xattrs and data are
	121	* taking up so much space that we might as well not keep trying to
	122	* expand it. The second is that xattr_sem is taken for writing, so
	123	* we shouldn't try to recurse into the inode expansion. For this
	124	* second case, we need to make sure that we take save and restore the
	125	* NO_EXPAND state flag appropriately.
	126	*/
	127	static inline void ext4_write_lock_xattr(struct inode inode, int save)
	128	{
	129	down_write(&EXT4_I(inode)->xattr_sem);
	130	*save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
	131	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
	132	}
	133
	134	static inline int ext4_write_trylock_xattr(struct inode inode, int save)
	135	{
	136	if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0)
	137	return 0;
	138	*save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
	139	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
	140	return 1;
	141	}
	142
	143	static inline void ext4_write_unlock_xattr(struct inode inode, int save)
	144	{
	145	if (*save == 0)
	146	ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
	147	up_write(&EXT4_I(inode)->xattr_sem);
	148	}
	149
617ba13b	150	extern ssize_t ext4_listxattr(struct dentry , char , size_t);
ac27a0ec	151
617ba13b	152	extern int ext4_xattr_get(struct inode , int, const char , void *, size_t);
617ba13b MC	153	extern int ext4_xattr_set(struct inode , int, const char , const void *, size_t, int);
617ba13b MC	154	extern int ext4_xattr_set_handle(handle_t , struct inode , int, const char , const void , size_t, int);
dec214d0	155	extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
af65207c TE	156	bool is_create, int *credits);
	157	extern int __ext4_xattr_set_credits(struct super_block sb, struct inode inode,
	158	struct buffer_head *block_bh, size_t value_len,
	159	bool is_create);
ac27a0ec	160
e50e5129	161	extern int ext4_xattr_delete_inode(handle_t handle, struct inode inode,
30a7eb97 TE	162	struct ext4_xattr_inode_array **array,
30a7eb97 TE	163	int extra_credits);
0421a189	164	extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
ac27a0ec	165
6dd4ee7c KS	166	extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
	167	struct ext4_inode raw_inode, handle_t handle);
	168
11e27528	169	extern const struct xattr_handler *ext4_xattr_handlers[];
ac27a0ec	170
879b3825 TM	171	extern int ext4_xattr_ibody_find(struct inode inode, struct ext4_xattr_info i,
	172	struct ext4_xattr_ibody_find *is);
	173	extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
	174	const char *name,
	175	void *buffer, size_t buffer_size);
0d812f77 TM	176	extern int ext4_xattr_ibody_inline_set(handle_t handle, struct inode inode,
	177	struct ext4_xattr_info *i,
	178	struct ext4_xattr_ibody_find *is);
879b3825	179
7a2508e1 JK	180	extern struct mb_cache *ext4_xattr_create_cache(void);
7a2508e1 JK	181	extern void ext4_xattr_destroy_cache(struct mb_cache *);
9c191f70	182
03010a33	183	#ifdef CONFIG_EXT4_FS_SECURITY
617ba13b	184	extern int ext4_init_security(handle_t handle, struct inode inode,
2a7dba39	185	struct inode dir, const struct qstr qstr);
ac27a0ec	186	#else
617ba13b	187	static inline int ext4_init_security(handle_t handle, struct inode inode,
2a7dba39	188	struct inode dir, const struct qstr qstr)
ac27a0ec DK	189	{
	190	return 0;
	191	}
	192	#endif
33d201e0 TE	193
	194	#ifdef CONFIG_LOCKDEP
	195	extern void ext4_xattr_inode_set_class(struct inode *ea_inode);
	196	#else
	197	static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { }
	198	#endif
7a9ca53a TE	199
7a9ca53a TE	200	extern int ext4_get_inode_usage(struct inode inode, qsize_t usage);