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linux
1/*
2 File: fs/ext4/xattr.h
3
4 On-disk format of extended attributes for the ext4 filesystem.
5
6 (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
7*/
8
9#include <linux/xattr.h>
10
11/* Magic value in attribute blocks */
12#define EXT4_XATTR_MAGIC 0xEA020000
13
14/* Maximum number of references to one attribute block */
15#define EXT4_XATTR_REFCOUNT_MAX 1024
16
17/* Name indexes */
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
25struct ext4_xattr_header {
26 __le32 h_magic; /* magic number for identification */
27 __le32 h_refcount; /* reference count */
28 __le32 h_blocks; /* number of disk blocks used */
29 __le32 h_hash; /* hash value of all attributes */
30 __le32 h_checksum; /* crc32c(uuid+id+xattrblock) */
31 /* id = inum if refcount=1, blknum otherwise */
32 __u32 h_reserved[3]; /* zero right now */
33};
34
35struct ext4_xattr_ibody_header {
36 __le32 h_magic; /* magic number for identification */
37};
38
39struct ext4_xattr_entry {
40 __u8 e_name_len; /* length of name */
41 __u8 e_name_index; /* attribute name index */
42 __le16 e_value_offs; /* offset in disk block of value */
43 __le32 e_value_block; /* disk block attribute is stored on (n/i) */
44 __le32 e_value_size; /* size of attribute value */
45 __le32 e_hash; /* hash value of name and value */
46 char e_name[0]; /* attribute name */
47};
48
49#define EXT4_XATTR_PAD_BITS 2
50#define EXT4_XATTR_PAD (1<<EXT4_XATTR_PAD_BITS)
51#define EXT4_XATTR_ROUND (EXT4_XATTR_PAD-1)
52#define EXT4_XATTR_LEN(name_len) \
53 (((name_len) + EXT4_XATTR_ROUND + \
54 sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
55#define EXT4_XATTR_NEXT(entry) \
56 ((struct ext4_xattr_entry *)( \
57 (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
58#define EXT4_XATTR_SIZE(size) \
59 (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
60
61#define IHDR(inode, raw_inode) \
62 ((struct ext4_xattr_ibody_header *) \
63 ((void *)raw_inode + \
64 EXT4_GOOD_OLD_INODE_SIZE + \
65 EXT4_I(inode)->i_extra_isize))
66#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
67
68# ifdef CONFIG_EXT4_FS_XATTR
69
70extern const struct xattr_handler ext4_xattr_user_handler;
71extern const struct xattr_handler ext4_xattr_trusted_handler;
72extern const struct xattr_handler ext4_xattr_acl_access_handler;
73extern const struct xattr_handler ext4_xattr_acl_default_handler;
74extern const struct xattr_handler ext4_xattr_security_handler;
75
76extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
77
78extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
79extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
80extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
81
82extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
83extern void ext4_xattr_put_super(struct super_block *);
84
85extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
86 struct ext4_inode *raw_inode, handle_t *handle);
87
88extern int __init ext4_init_xattr(void);
89extern void ext4_exit_xattr(void);
90
91extern const struct xattr_handler *ext4_xattr_handlers[];
92
93# else /* CONFIG_EXT4_FS_XATTR */
94
95static inline int
96ext4_xattr_get(struct inode *inode, int name_index, const char *name,
97 void *buffer, size_t size, int flags)
98{
99 return -EOPNOTSUPP;
100}
101
102static inline int
103ext4_xattr_set(struct inode *inode, int name_index, const char *name,
104 const void *value, size_t size, int flags)
105{
106 return -EOPNOTSUPP;
107}
108
109static inline int
110ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
111 const char *name, const void *value, size_t size, int flags)
112{
113 return -EOPNOTSUPP;
114}
115
116static inline void
117ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
118{
119}
120
121static inline void
122ext4_xattr_put_super(struct super_block *sb)
123{
124}
125
126static __init inline int
127ext4_init_xattr(void)
128{
129 return 0;
130}
131
132static inline void
133ext4_exit_xattr(void)
134{
135}
136
137static inline int
138ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
139 struct ext4_inode *raw_inode, handle_t *handle)
140{
141 return -EOPNOTSUPP;
142}
143
144#define ext4_xattr_handlers NULL
145
146# endif /* CONFIG_EXT4_FS_XATTR */
147
148#ifdef CONFIG_EXT4_FS_SECURITY
149extern int ext4_init_security(handle_t *handle, struct inode *inode,
150 struct inode *dir, const struct qstr *qstr);
151#else
152static inline int ext4_init_security(handle_t *handle, struct inode *inode,
153 struct inode *dir, const struct qstr *qstr)
154{
155 return 0;
156}
157#endif