1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 File: linux/ext2_xattr.h
4
5 On-disk format of extended attributes for the ext2 filesystem.
6
7 (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
8 */
9
10 #include <linux/init.h>
11 #include <linux/xattr.h>
12
13 /* Magic value in attribute blocks */
14 #define EXT2_XATTR_MAGIC 0xEA020000
15
16 /* Maximum number of references to one attribute block */
17 #define EXT2_XATTR_REFCOUNT_MAX 1024
18
19 /* Name indexes */
20 #define EXT2_XATTR_INDEX_USER 1
21 #define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS 2
22 #define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT 3
23 #define EXT2_XATTR_INDEX_TRUSTED 4
24 #define EXT2_XATTR_INDEX_LUSTRE 5
25 #define EXT2_XATTR_INDEX_SECURITY 6
26
27 struct ext2_xattr_header {
28 __le32 h_magic; /* magic number for identification */
29 __le32 h_refcount; /* reference count */
30 __le32 h_blocks; /* number of disk blocks used */
31 __le32 h_hash; /* hash value of all attributes */
32 __u32 h_reserved[4]; /* zero right now */
33 };
34
35 struct ext2_xattr_entry {
36 __u8 e_name_len; /* length of name */
37 __u8 e_name_index; /* attribute name index */
38 __le16 e_value_offs; /* offset in disk block of value */
39 __le32 e_value_block; /* disk block attribute is stored on (n/i) */
40 __le32 e_value_size; /* size of attribute value */
41 __le32 e_hash; /* hash value of name and value */
42 char e_name[]; /* attribute name */
43 };
44
45 #define EXT2_XATTR_PAD_BITS 2
46 #define EXT2_XATTR_PAD (1<<EXT2_XATTR_PAD_BITS)
47 #define EXT2_XATTR_ROUND (EXT2_XATTR_PAD-1)
48 #define EXT2_XATTR_LEN(name_len) \
49 (((name_len) + EXT2_XATTR_ROUND + \
50 sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
51 #define EXT2_XATTR_NEXT(entry) \
52 ( (struct ext2_xattr_entry *)( \
53 (char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
54 #define EXT2_XATTR_SIZE(size) \
55 (((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
56
57 struct mb_cache;
58
59 # ifdef CONFIG_EXT2_FS_XATTR
60
61 extern const struct xattr_handler ext2_xattr_user_handler;
62 extern const struct xattr_handler ext2_xattr_trusted_handler;
63 extern const struct xattr_handler ext2_xattr_security_handler;
64
65 extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
66
67 extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
68 extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
69
70 extern void ext2_xattr_delete_inode(struct inode *);
71
72 extern struct mb_cache *ext2_xattr_create_cache(void);
73 extern void ext2_xattr_destroy_cache(struct mb_cache *cache);
74
75 extern const struct xattr_handler * const ext2_xattr_handlers[];
76
77 # else /* CONFIG_EXT2_FS_XATTR */
78
79 static inline int
80 ext2_xattr_get(struct inode *inode, int name_index,
81 const char *name, void *buffer, size_t size)
82 {
83 return -EOPNOTSUPP;
84 }
85
86 static inline int
87 ext2_xattr_set(struct inode *inode, int name_index, const char *name,
88 const void *value, size_t size, int flags)
89 {
90 return -EOPNOTSUPP;
91 }
92
93 static inline void
94 ext2_xattr_delete_inode(struct inode *inode)
95 {
96 }
97
98 static inline void ext2_xattr_destroy_cache(struct mb_cache *cache)
99 {
100 }
101
102 #define ext2_xattr_handlers NULL
103 #define ext2_listxattr NULL
104
105 # endif /* CONFIG_EXT2_FS_XATTR */
106
107 #ifdef CONFIG_EXT2_FS_SECURITY
108 extern int ext2_init_security(struct inode *inode, struct inode *dir,
109 const struct qstr *qstr);
110 #else
111 static inline int ext2_init_security(struct inode *inode, struct inode *dir,
112 const struct qstr *qstr)
113 {
114 return 0;
115 }
116 #endif
117
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