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
28 struct ext4_xattr_header {
29 __le32 h_magic; /* magic number for identification */
30 __le32 h_refcount; /* reference count */
31 __le32 h_blocks; /* number of disk blocks used */
32 __le32 h_hash; /* hash value of all attributes */
33 __le32 h_checksum; /* crc32c(uuid+id+xattrblock) */
34 /* id = inum if refcount=1, blknum otherwise */
35 __u32 h_reserved[3]; /* zero right now */
36 };
37
38 struct ext4_xattr_ibody_header {
39 __le32 h_magic; /* magic number for identification */
40 };
41
42 struct ext4_xattr_entry {
43 __u8 e_name_len; /* length of name */
44 __u8 e_name_index; /* attribute name index */
45 __le16 e_value_offs; /* offset in disk block of value */
46 __le32 e_value_block; /* disk block attribute is stored on (n/i) */
47 __le32 e_value_size; /* size of attribute value */
48 __le32 e_hash; /* hash value of name and value */
49 char e_name[0]; /* attribute name */
50 };
51
52 #define EXT4_XATTR_PAD_BITS 2
53 #define EXT4_XATTR_PAD (1<<EXT4_XATTR_PAD_BITS)
54 #define EXT4_XATTR_ROUND (EXT4_XATTR_PAD-1)
55 #define EXT4_XATTR_LEN(name_len) \
56 (((name_len) + EXT4_XATTR_ROUND + \
57 sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
58 #define EXT4_XATTR_NEXT(entry) \
59 ((struct ext4_xattr_entry *)( \
60 (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
61 #define EXT4_XATTR_SIZE(size) \
62 (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
63
64 #define IHDR(inode, raw_inode) \
65 ((struct ext4_xattr_ibody_header *) \
66 ((void *)raw_inode + \
67 EXT4_GOOD_OLD_INODE_SIZE + \
68 EXT4_I(inode)->i_extra_isize))
69 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
70
71 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
72 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
73 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
74 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
75
76 #define EXT4_ZERO_XATTR_VALUE ((void *)-1)
77
78 struct ext4_xattr_info {
79 int name_index;
80 const char *name;
81 const void *value;
82 size_t value_len;
83 };
84
85 struct ext4_xattr_search {
86 struct ext4_xattr_entry *first;
87 void *base;
88 void *end;
89 struct ext4_xattr_entry *here;
90 int not_found;
91 };
92
93 struct ext4_xattr_ibody_find {
94 struct ext4_xattr_search s;
95 struct ext4_iloc iloc;
96 };
97
98 extern const struct xattr_handler ext4_xattr_user_handler;
99 extern const struct xattr_handler ext4_xattr_trusted_handler;
100 extern const struct xattr_handler ext4_xattr_security_handler;
101
102 #define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"
103
104 /*
105 * The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes.
106 * The first is to signal that there the inline xattrs and data are
107 * taking up so much space that we might as well not keep trying to
108 * expand it. The second is that xattr_sem is taken for writing, so
109 * we shouldn't try to recurse into the inode expansion. For this
110 * second case, we need to make sure that we take save and restore the
111 * NO_EXPAND state flag appropriately.
112 */
ext4_write_lock_xattr(struct inode * inode,int * save)113 static inline void ext4_write_lock_xattr(struct inode *inode, int *save)
114 {
115 down_write(&EXT4_I(inode)->xattr_sem);
116 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
117 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
118 }
119
ext4_write_trylock_xattr(struct inode * inode,int * save)120 static inline int ext4_write_trylock_xattr(struct inode *inode, int *save)
121 {
122 if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0)
123 return 0;
124 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
125 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
126 return 1;
127 }
128
ext4_write_unlock_xattr(struct inode * inode,int * save)129 static inline void ext4_write_unlock_xattr(struct inode *inode, int *save)
130 {
131 if (*save == 0)
132 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
133 up_write(&EXT4_I(inode)->xattr_sem);
134 }
135
136 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
137
138 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
139 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
140 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
141
142 extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
143
144 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
145 struct ext4_inode *raw_inode, handle_t *handle);
146
147 extern const struct xattr_handler *ext4_xattr_handlers[];
148
149 extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
150 struct ext4_xattr_ibody_find *is);
151 extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
152 const char *name,
153 void *buffer, size_t buffer_size);
154 extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
155 struct ext4_xattr_info *i,
156 struct ext4_xattr_ibody_find *is);
157
158 extern struct mb2_cache *ext4_xattr_create_cache(void);
159 extern void ext4_xattr_destroy_cache(struct mb2_cache *);
160
161 #ifdef CONFIG_EXT4_FS_SECURITY
162 extern int ext4_init_security(handle_t *handle, struct inode *inode,
163 struct inode *dir, const struct qstr *qstr);
164 #else
ext4_init_security(handle_t * handle,struct inode * inode,struct inode * dir,const struct qstr * qstr)165 static inline int ext4_init_security(handle_t *handle, struct inode *inode,
166 struct inode *dir, const struct qstr *qstr)
167 {
168 return 0;
169 }
170 #endif
171