4 On-disk format of extended attributes for the ext4 filesystem.
6 (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
9 #include <linux/xattr.h>
11 /* Magic value in attribute blocks */
12 #define EXT4_XATTR_MAGIC 0xEA020000
14 /* Maximum number of references to one attribute block */
15 #define EXT4_XATTR_REFCOUNT_MAX 1024
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
24 #define EXT4_XATTR_INDEX_SYSTEM 7
25 #define EXT4_XATTR_INDEX_RICHACL 8
26 #define EXT4_XATTR_INDEX_ENCRYPTION 9
27 #define EXT4_XATTR_INDEX_HURD 10 /* Reserved for Hurd */
29 struct ext4_xattr_header {
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 */
34 __le32 h_checksum; /* crc32c(uuid+id+xattrblock) */
35 /* id = inum if refcount=1, blknum otherwise */
36 __u32 h_reserved[3]; /* zero right now */
39 struct ext4_xattr_ibody_header {
40 __le32 h_magic; /* magic number for identification */
43 struct ext4_xattr_entry {
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 */
47 __le32 e_value_block; /* disk block attribute is stored on (n/i) */
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 */
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) \
60 ((struct ext4_xattr_entry *)( \
61 (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
62 #define EXT4_XATTR_SIZE(size) \
63 (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
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))
72 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
73 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
74 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
75 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
77 #define EXT4_ZERO_XATTR_VALUE ((void *)-1)
80 * If we want to add an xattr to the inode, we should make sure that
81 * i_extra_isize is not 0 and that the inode size is not less than
82 * EXT4_GOOD_OLD_INODE_SIZE + extra_isize + pad.
83 * EXT4_GOOD_OLD_INODE_SIZE extra_isize header entry pad data
84 * |--------------------------|------------|------|---------|---|-------|
86 #define EXT4_INODE_HAS_XATTR_SPACE(inode) \
87 ((EXT4_I(inode)->i_extra_isize != 0) && \
88 (EXT4_GOOD_OLD_INODE_SIZE + EXT4_I(inode)->i_extra_isize + \
89 sizeof(struct ext4_xattr_ibody_header) + EXT4_XATTR_PAD <= \
90 EXT4_INODE_SIZE((inode)->i_sb)))
92 struct ext4_xattr_info {
99 struct ext4_xattr_search {
100 struct ext4_xattr_entry *first;
103 struct ext4_xattr_entry *here;
107 struct ext4_xattr_ibody_find {
108 struct ext4_xattr_search s;
109 struct ext4_iloc iloc;
112 extern const struct xattr_handler ext4_xattr_user_handler;
113 extern const struct xattr_handler ext4_xattr_trusted_handler;
114 extern const struct xattr_handler ext4_xattr_security_handler;
116 #define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"
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.
127 static inline void ext4_write_lock_xattr(struct inode *inode, int *save)
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);
134 static inline int ext4_write_trylock_xattr(struct inode *inode, int *save)
136 if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0)
138 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
139 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
143 static inline void ext4_write_unlock_xattr(struct inode *inode, int *save)
146 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
147 up_write(&EXT4_I(inode)->xattr_sem);
150 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
152 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
153 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
154 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
156 extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
158 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
159 struct ext4_inode *raw_inode, handle_t *handle);
161 extern const struct xattr_handler *ext4_xattr_handlers[];
163 extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
164 struct ext4_xattr_ibody_find *is);
165 extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
167 void *buffer, size_t buffer_size);
168 extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
169 struct ext4_xattr_info *i,
170 struct ext4_xattr_ibody_find *is);
172 extern struct mb_cache *ext4_xattr_create_cache(void);
173 extern void ext4_xattr_destroy_cache(struct mb_cache *);
175 #ifdef CONFIG_EXT4_FS_SECURITY
176 extern int ext4_init_security(handle_t *handle, struct inode *inode,
177 struct inode *dir, const struct qstr *qstr);
179 static inline int ext4_init_security(handle_t *handle, struct inode *inode,
180 struct inode *dir, const struct qstr *qstr)