xref: /openbmc/linux/fs/ext2/xattr.h (revision 47aab533)
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
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
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
94  ext2_xattr_delete_inode(struct inode *inode)
95  {
96  }
97  
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
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