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 #include <linux/config.h>
11 /* Magic value in attribute blocks */
12 #define EXT2_EXT_ATTR_MAGIC 0xEA010000
14 /* Maximum number of references to one attribute block */
15 #define EXT2_EXT_ATTR_REFCOUNT_MAX 1024
17 struct ext2_ext_attr_header {
18 __u32 h_magic; /* magic number for identification */
19 __u32 h_refcount; /* reference count */
20 __u32 h_blocks; /* number of disk blocks used */
21 __u32 h_hash; /* hash value of all attributes */
22 __u32 h_reserved[4]; /* zero right now */
25 struct ext2_ext_attr_entry {
26 __u8 e_name_len; /* length of name */
27 __u8 e_name_index; /* index into table of names (n/i) */
28 __u16 e_value_offs; /* offset in disk block of value */
29 __u32 e_value_block; /* disk block attribute is stored on (n/i) */
30 __u32 e_value_size; /* size of attribute value */
31 __u32 e_hash; /* hash value of name and value */
32 char e_name[0]; /* attribute name */
35 #define EXT2_EXT_ATTR_PAD_BITS 2
36 #define EXT2_EXT_ATTR_PAD (1<<EXT2_EXT_ATTR_PAD_BITS)
37 #define EXT2_EXT_ATTR_ROUND (EXT2_EXT_ATTR_PAD-1)
38 #define EXT2_EXT_ATTR_LEN(name_len) \
39 (((name_len) + EXT2_EXT_ATTR_ROUND + \
40 sizeof(struct ext2_ext_attr_entry)) & ~EXT2_EXT_ATTR_ROUND)
41 #define EXT2_EXT_ATTR_NEXT(entry) \
42 ( (struct ext2_ext_attr_entry *)( \
43 (char *)(entry) + EXT2_EXT_ATTR_LEN((entry)->e_name_len)) )
44 #define EXT2_EXT_ATTR_SIZE(size) \
45 (((size) + EXT2_EXT_ATTR_ROUND) & ~EXT2_EXT_ATTR_ROUND)
48 # ifdef CONFIG_EXT2_FS_EXT_ATTR
49 extern int ext2_get_ext_attr(struct inode *, const char *, char *, size_t, int);
50 extern int ext2_set_ext_attr(struct inode *, const char *, char *, size_t, int);
51 extern void ext2_ext_attr_free_inode(struct inode *inode);
52 extern void ext2_ext_attr_put_super(struct super_block *sb);
53 extern int ext2_ext_attr_init(void);
54 extern void ext2_ext_attr_done(void);
56 # define ext2_get_ext_attr NULL
57 # define ext2_set_ext_attr NULL
59 #endif /* __KERNEL__ */