xref: /openbmc/linux/fs/ext4/xattr.h (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 
25 struct 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 	__u32	h_reserved[4];	/* zero right now */
31 };
32 
33 struct ext4_xattr_ibody_header {
34 	__le32	h_magic;	/* magic number for identification */
35 };
36 
37 struct ext4_xattr_entry {
38 	__u8	e_name_len;	/* length of name */
39 	__u8	e_name_index;	/* attribute name index */
40 	__le16	e_value_offs;	/* offset in disk block of value */
41 	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
42 	__le32	e_value_size;	/* size of attribute value */
43 	__le32	e_hash;		/* hash value of name and value */
44 	char	e_name[0];	/* attribute name */
45 };
46 
47 #define EXT4_XATTR_PAD_BITS		2
48 #define EXT4_XATTR_PAD		(1<<EXT4_XATTR_PAD_BITS)
49 #define EXT4_XATTR_ROUND		(EXT4_XATTR_PAD-1)
50 #define EXT4_XATTR_LEN(name_len) \
51 	(((name_len) + EXT4_XATTR_ROUND + \
52 	sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
53 #define EXT4_XATTR_NEXT(entry) \
54 	( (struct ext4_xattr_entry *)( \
55 	  (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)) )
56 #define EXT4_XATTR_SIZE(size) \
57 	(((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
58 
59 # ifdef CONFIG_EXT4DEV_FS_XATTR
60 
61 extern struct xattr_handler ext4_xattr_user_handler;
62 extern struct xattr_handler ext4_xattr_trusted_handler;
63 extern struct xattr_handler ext4_xattr_acl_access_handler;
64 extern struct xattr_handler ext4_xattr_acl_default_handler;
65 extern struct xattr_handler ext4_xattr_security_handler;
66 
67 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
68 
69 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
70 extern int ext4_xattr_list(struct inode *, char *, size_t);
71 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
72 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
73 
74 extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
75 extern void ext4_xattr_put_super(struct super_block *);
76 
77 extern int init_ext4_xattr(void);
78 extern void exit_ext4_xattr(void);
79 
80 extern struct xattr_handler *ext4_xattr_handlers[];
81 
82 # else  /* CONFIG_EXT4DEV_FS_XATTR */
83 
84 static inline int
85 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
86 	       void *buffer, size_t size, int flags)
87 {
88 	return -EOPNOTSUPP;
89 }
90 
91 static inline int
92 ext4_xattr_list(struct inode *inode, void *buffer, size_t size)
93 {
94 	return -EOPNOTSUPP;
95 }
96 
97 static inline int
98 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
99 	       const void *value, size_t size, int flags)
100 {
101 	return -EOPNOTSUPP;
102 }
103 
104 static inline int
105 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
106 	       const char *name, const void *value, size_t size, int flags)
107 {
108 	return -EOPNOTSUPP;
109 }
110 
111 static inline void
112 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
113 {
114 }
115 
116 static inline void
117 ext4_xattr_put_super(struct super_block *sb)
118 {
119 }
120 
121 static inline int
122 init_ext4_xattr(void)
123 {
124 	return 0;
125 }
126 
127 static inline void
128 exit_ext4_xattr(void)
129 {
130 }
131 
132 #define ext4_xattr_handlers	NULL
133 
134 # endif  /* CONFIG_EXT4DEV_FS_XATTR */
135 
136 #ifdef CONFIG_EXT4DEV_FS_SECURITY
137 extern int ext4_init_security(handle_t *handle, struct inode *inode,
138 				struct inode *dir);
139 #else
140 static inline int ext4_init_security(handle_t *handle, struct inode *inode,
141 				struct inode *dir)
142 {
143 	return 0;
144 }
145 #endif
146