xref: /linux/fs/ext4/xattr.h (revision b85d45947951d23cb22d90caecf4c1eb81342c96)
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 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
105 
106 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
107 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
108 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
109 
110 extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
111 extern void ext4_xattr_put_super(struct super_block *);
112 
113 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
114 			    struct ext4_inode *raw_inode, handle_t *handle);
115 
116 extern const struct xattr_handler *ext4_xattr_handlers[];
117 
118 extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
119 				 struct ext4_xattr_ibody_find *is);
120 extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
121 				const char *name,
122 				void *buffer, size_t buffer_size);
123 extern 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 
127 extern struct mb_cache *ext4_xattr_create_cache(char *name);
128 extern void ext4_xattr_destroy_cache(struct mb_cache *);
129 
130 #ifdef CONFIG_EXT4_FS_SECURITY
131 extern int ext4_init_security(handle_t *handle, struct inode *inode,
132 			      struct inode *dir, const struct qstr *qstr);
133 #else
134 static 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
140