1/*
2  File: linux/ext2_xattr.h
3
4  On-disk format of extended attributes for the ext2 filesystem.
5
6  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
7*/
8
9#include <linux/init.h>
10#include <linux/xattr.h>
11
12/* Magic value in attribute blocks */
13#define EXT2_XATTR_MAGIC		0xEA020000
14
15/* Maximum number of references to one attribute block */
16#define EXT2_XATTR_REFCOUNT_MAX		1024
17
18/* Name indexes */
19#define EXT2_XATTR_INDEX_USER			1
20#define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS	2
21#define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT	3
22#define EXT2_XATTR_INDEX_TRUSTED		4
23#define	EXT2_XATTR_INDEX_LUSTRE			5
24#define EXT2_XATTR_INDEX_SECURITY	        6
25
26struct ext2_xattr_header {
27	__le32	h_magic;	/* magic number for identification */
28	__le32	h_refcount;	/* reference count */
29	__le32	h_blocks;	/* number of disk blocks used */
30	__le32	h_hash;		/* hash value of all attributes */
31	__u32	h_reserved[4];	/* zero right now */
32};
33
34struct ext2_xattr_entry {
35	__u8	e_name_len;	/* length of name */
36	__u8	e_name_index;	/* attribute name index */
37	__le16	e_value_offs;	/* offset in disk block of value */
38	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
39	__le32	e_value_size;	/* size of attribute value */
40	__le32	e_hash;		/* hash value of name and value */
41	char	e_name[0];	/* attribute name */
42};
43
44#define EXT2_XATTR_PAD_BITS		2
45#define EXT2_XATTR_PAD		(1<<EXT2_XATTR_PAD_BITS)
46#define EXT2_XATTR_ROUND		(EXT2_XATTR_PAD-1)
47#define EXT2_XATTR_LEN(name_len) \
48	(((name_len) + EXT2_XATTR_ROUND + \
49	sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
50#define EXT2_XATTR_NEXT(entry) \
51	( (struct ext2_xattr_entry *)( \
52	  (char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
53#define EXT2_XATTR_SIZE(size) \
54	(((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
55
56# ifdef CONFIG_EXT2_FS_XATTR
57
58extern struct xattr_handler ext2_xattr_user_handler;
59extern struct xattr_handler ext2_xattr_trusted_handler;
60extern struct xattr_handler ext2_xattr_acl_access_handler;
61extern struct xattr_handler ext2_xattr_acl_default_handler;
62extern struct xattr_handler ext2_xattr_security_handler;
63
64extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
65
66extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
67extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
68
69extern void ext2_xattr_delete_inode(struct inode *);
70extern void ext2_xattr_put_super(struct super_block *);
71
72extern int init_ext2_xattr(void);
73extern void exit_ext2_xattr(void);
74
75extern struct xattr_handler *ext2_xattr_handlers[];
76
77# else  /* CONFIG_EXT2_FS_XATTR */
78
79static inline int
80ext2_xattr_get(struct inode *inode, int name_index,
81	       const char *name, void *buffer, size_t size)
82{
83	return -EOPNOTSUPP;
84}
85
86static inline int
87ext2_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
93static inline void
94ext2_xattr_delete_inode(struct inode *inode)
95{
96}
97
98static inline void
99ext2_xattr_put_super(struct super_block *sb)
100{
101}
102
103static inline int
104init_ext2_xattr(void)
105{
106	return 0;
107}
108
109static inline void
110exit_ext2_xattr(void)
111{
112}
113
114#define ext2_xattr_handlers NULL
115
116# endif  /* CONFIG_EXT2_FS_XATTR */
117
118#ifdef CONFIG_EXT2_FS_SECURITY
119extern int ext2_init_security(struct inode *inode, struct inode *dir);
120#else
121static inline int ext2_init_security(struct inode *inode, struct inode *dir)
122{
123	return 0;
124}
125#endif
126