xref: /openbmc/linux/fs/ext2/xattr.h (revision 91a08715)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3   File: linux/ext2_xattr.h
4 
5   On-disk format of extended attributes for the ext2 filesystem.
6 
7   (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
8 */
9 
10 #include <linux/init.h>
11 #include <linux/xattr.h>
12 
13 /* Magic value in attribute blocks */
14 #define EXT2_XATTR_MAGIC		0xEA020000
15 
16 /* Maximum number of references to one attribute block */
17 #define EXT2_XATTR_REFCOUNT_MAX		1024
18 
19 /* Name indexes */
20 #define EXT2_XATTR_INDEX_USER			1
21 #define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS	2
22 #define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT	3
23 #define EXT2_XATTR_INDEX_TRUSTED		4
24 #define	EXT2_XATTR_INDEX_LUSTRE			5
25 #define EXT2_XATTR_INDEX_SECURITY	        6
26 
27 struct ext2_xattr_header {
28 	__le32	h_magic;	/* magic number for identification */
29 	__le32	h_refcount;	/* reference count */
30 	__le32	h_blocks;	/* number of disk blocks used */
31 	__le32	h_hash;		/* hash value of all attributes */
32 	__u32	h_reserved[4];	/* zero right now */
33 };
34 
35 struct ext2_xattr_entry {
36 	__u8	e_name_len;	/* length of name */
37 	__u8	e_name_index;	/* attribute name index */
38 	__le16	e_value_offs;	/* offset in disk block of value */
39 	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
40 	__le32	e_value_size;	/* size of attribute value */
41 	__le32	e_hash;		/* hash value of name and value */
42 	char	e_name[];	/* attribute name */
43 };
44 
45 #define EXT2_XATTR_PAD_BITS		2
46 #define EXT2_XATTR_PAD		(1<<EXT2_XATTR_PAD_BITS)
47 #define EXT2_XATTR_ROUND		(EXT2_XATTR_PAD-1)
48 #define EXT2_XATTR_LEN(name_len) \
49 	(((name_len) + EXT2_XATTR_ROUND + \
50 	sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
51 #define EXT2_XATTR_NEXT(entry) \
52 	( (struct ext2_xattr_entry *)( \
53 	  (char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
54 #define EXT2_XATTR_SIZE(size) \
55 	(((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
56 
57 struct mb_cache;
58 
59 # ifdef CONFIG_EXT2_FS_XATTR
60 
61 extern const struct xattr_handler ext2_xattr_user_handler;
62 extern const struct xattr_handler ext2_xattr_trusted_handler;
63 extern const struct xattr_handler ext2_xattr_security_handler;
64 
65 extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
66 
67 extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
68 extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
69 
70 extern void ext2_xattr_delete_inode(struct inode *);
71 
72 extern struct mb_cache *ext2_xattr_create_cache(void);
73 extern void ext2_xattr_destroy_cache(struct mb_cache *cache);
74 
75 extern const struct xattr_handler *ext2_xattr_handlers[];
76 
77 # else  /* CONFIG_EXT2_FS_XATTR */
78 
79 static inline int
ext2_xattr_get(struct inode * inode,int name_index,const char * name,void * buffer,size_t size)80 ext2_xattr_get(struct inode *inode, int name_index,
81 	       const char *name, void *buffer, size_t size)
82 {
83 	return -EOPNOTSUPP;
84 }
85 
86 static inline int
ext2_xattr_set(struct inode * inode,int name_index,const char * name,const void * value,size_t size,int flags)87 ext2_xattr_set(struct inode *inode, int name_index, const char *name,
88 	       const void *value, size_t size, int flags)
89 {
90 	return -EOPNOTSUPP;
91 }
92 
93 static inline void
ext2_xattr_delete_inode(struct inode * inode)94 ext2_xattr_delete_inode(struct inode *inode)
95 {
96 }
97 
ext2_xattr_destroy_cache(struct mb_cache * cache)98 static inline void ext2_xattr_destroy_cache(struct mb_cache *cache)
99 {
100 }
101 
102 #define ext2_xattr_handlers NULL
103 #define ext2_listxattr NULL
104 
105 # endif  /* CONFIG_EXT2_FS_XATTR */
106 
107 #ifdef CONFIG_EXT2_FS_SECURITY
108 extern int ext2_init_security(struct inode *inode, struct inode *dir,
109 			      const struct qstr *qstr);
110 #else
ext2_init_security(struct inode * inode,struct inode * dir,const struct qstr * qstr)111 static inline int ext2_init_security(struct inode *inode, struct inode *dir,
112 				     const struct qstr *qstr)
113 {
114 	return 0;
115 }
116 #endif
117