2 File: linux/ext2_ext_attr.h
4 On-disk format of extended attributes for the ext2 filesystem.
6 (C) 2000 Andreas Gruenbacher, <a.gruenbacher@computer.org>
9 #ifndef _EXT2_EXT_ATTR_H
10 #define _EXT2_EXT_ATTR_H
11 /* Magic value in attribute blocks */
12 #define EXT2_EXT_ATTR_MAGIC_v1 0xEA010000
13 #define EXT2_EXT_ATTR_MAGIC 0xEA020000
15 /* Maximum number of references to one attribute block */
16 #define EXT2_EXT_ATTR_REFCOUNT_MAX 1024
18 struct ext2_ext_attr_header {
19 __u32 h_magic; /* magic number for identification */
20 __u32 h_refcount; /* reference count */
21 __u32 h_blocks; /* number of disk blocks used */
22 __u32 h_hash; /* hash value of all attributes */
23 __u32 h_checksum; /* crc32c(uuid+id+xattrs) */
24 /* id = inum if refcount = 1, else blknum */
25 __u32 h_reserved[3]; /* zero right now */
28 struct ext2_ext_attr_entry {
29 __u8 e_name_len; /* length of name */
30 __u8 e_name_index; /* attribute name index */
31 __u16 e_value_offs; /* offset in disk block of value */
32 __u32 e_value_inum; /* inode in which the value is stored */
33 __u32 e_value_size; /* size of attribute value */
34 __u32 e_hash; /* hash value of name and value */
36 char e_name[0]; /* attribute name */
40 #define BHDR(block) ((struct ext2_ext_attr_header *)block)
41 #define IHDR(inode) ((__u32 *)((char *)inode + EXT2_GOOD_OLD_INODE_SIZE + \
42 (inode)->i_extra_isize))
43 #define ENTRY(ptr) ((struct ext2_ext_attr_entry *)(ptr))
46 #define EXT2_ATTR_INDEX_USER 1
47 #define EXT2_ATTR_INDEX_POSIX_ACL_ACCESS 2
48 #define EXT2_ATTR_INDEX_POSIX_ACL_DEFAULT 3
49 #define EXT2_ATTR_INDEX_TRUSTED 4
50 #define EXT2_ATTR_INDEX_LUSTRE 5
51 #define EXT2_ATTR_INDEX_SECURITY 6
52 #define EXT2_ATTR_INDEX_MAX 7
54 #define EXT2_ATTR_INDEX_USER_PREFIX "user."
55 #define EXT2_ATTR_INDEX_POSIX_ACL_ACCESS_PREFIX "system.posix_acl_access"
56 #define EXT2_ATTR_INDEX_POSIX_ACL_DEFAULT_PREFIX "system.posix_acl_default"
57 #define EXT2_ATTR_INDEX_TRUSTED_PREFIX "trusted."
58 #define EXT2_ATTR_INDEX_LUSTRE_PREFIX "lustre."
59 #define EXT2_ATTR_INDEX_SECURITY_PREFIX "security."
61 #define EXT2_ATTR_PREFIX(index) (index ## _PREFIX)
62 #define EXT2_ATTR_PREFIX_LEN(index) (index ## _PRE_LEN)
64 #define EXT2_EXT_ATTR_PAD_BITS 2
65 #define EXT2_EXT_ATTR_PAD ((unsigned) 1<<EXT2_EXT_ATTR_PAD_BITS)
66 #define EXT2_EXT_ATTR_ROUND (EXT2_EXT_ATTR_PAD-1)
67 #define EXT2_EXT_ATTR_LEN(name_len) \
68 (((name_len) + EXT2_EXT_ATTR_ROUND + \
69 sizeof(struct ext2_ext_attr_entry)) & ~EXT2_EXT_ATTR_ROUND)
70 #define EXT2_EXT_ATTR_NEXT(entry) \
71 ( (struct ext2_ext_attr_entry *)( \
72 (char *)(entry) + EXT2_EXT_ATTR_LEN((entry)->e_name_len)) )
73 #define EXT2_EXT_ATTR_SIZE(size) \
74 (((size) + EXT2_EXT_ATTR_ROUND) & ~EXT2_EXT_ATTR_ROUND)
75 #define EXT2_EXT_IS_LAST_ENTRY(entry) (*((__u32 *)(entry)) == 0UL)
76 #define EXT2_EXT_ATTR_NAME(entry) \
77 (((char *) (entry)) + sizeof(struct ext2_ext_attr_entry))
78 #define EXT2_XATTR_LEN(name_len) \
79 (((name_len) + EXT2_EXT_ATTR_ROUND + \
80 sizeof(struct ext2_xattr_entry)) & ~EXT2_EXT_ATTR_ROUND)
81 #define EXT2_XATTR_SIZE(size) \
82 (((size) + EXT2_EXT_ATTR_ROUND) & ~EXT2_EXT_ATTR_ROUND)
85 * XATTR_SIZE_MAX is currently 64k, but for the purposes of checking
86 * for file system consistency errors, we use a somewhat bigger value.
87 * This allows XATTR_SIZE_MAX to grow in the future, but by using this
88 * instead of INT_MAX for certain consistency checks, we don't need to
89 * worry about arithmetic overflows. (Actually XATTR_SIZE_MAX is
90 * defined in include/uapi/linux/limits.h, so changing it is going
91 * not going to be trivial....)
93 #define EXT2_XATTR_SIZE_MAX (1 << 24)
96 # ifdef CONFIG_EXT2_FS_EXT_ATTR
97 extern int ext2_get_ext_attr(struct inode *, const char *, char *, size_t, int);
98 extern int ext2_set_ext_attr(struct inode *, const char *, char *, size_t, int);
99 extern void ext2_ext_attr_free_inode(struct inode *inode);
100 extern void ext2_ext_attr_put_super(struct super_block *sb);
101 extern int ext2_ext_attr_init(void);
102 extern void ext2_ext_attr_done(void);
104 # define ext2_get_ext_attr NULL
105 # define ext2_set_ext_attr NULL
107 #endif /* __KERNEL__ */
108 #endif /* _EXT2_EXT_ATTR_H */