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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#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 */
28
29struct 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 */
37};
38
39struct ext4_xattr_ibody_header {
40 __le32 h_magic; /* magic number for identification */
41};
42
43struct 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 */
51};
52
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)
64
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))
71
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)
76
77#define EXT4_ZERO_XATTR_VALUE ((void *)-1)
78
79struct ext4_xattr_info {
80 int name_index;
81 const char *name;
82 const void *value;
83 size_t value_len;
84};
85
86struct ext4_xattr_search {
87 struct ext4_xattr_entry *first;
88 void *base;
89 void *end;
90 struct ext4_xattr_entry *here;
91 int not_found;
92};
93
94struct ext4_xattr_ibody_find {
95 struct ext4_xattr_search s;
96 struct ext4_iloc iloc;
97};
98
99extern const struct xattr_handler ext4_xattr_user_handler;
100extern const struct xattr_handler ext4_xattr_trusted_handler;
101extern const struct xattr_handler ext4_xattr_security_handler;
102
103#define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"
104
105extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
106
107extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
108extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
109extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
110
111extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
112
113extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
114 struct ext4_inode *raw_inode, handle_t *handle);
115
116extern const struct xattr_handler *ext4_xattr_handlers[];
117
118extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
119 struct ext4_xattr_ibody_find *is);
120extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
121 const char *name,
122 void *buffer, size_t buffer_size);
123extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
124 struct ext4_xattr_info *i,
125 struct ext4_xattr_ibody_find *is);
126
127extern struct mb_cache *ext4_xattr_create_cache(void);
128extern void ext4_xattr_destroy_cache(struct mb_cache *);
129
130#ifdef CONFIG_EXT4_FS_SECURITY
131extern int ext4_init_security(handle_t *handle, struct inode *inode,
132 struct inode *dir, const struct qstr *qstr);
133#else
134static inline int ext4_init_security(handle_t *handle, struct inode *inode,
135 struct inode *dir, const struct qstr *qstr)
136{
137 return 0;
138}
139#endif