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
27struct ext4_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	__le32	h_checksum;	/* crc32c(uuid+id+xattrblock) */
33				/* id = inum if refcount=1, blknum otherwise */
34	__u32	h_reserved[3];	/* zero right now */
35};
36
37struct ext4_xattr_ibody_header {
38	__le32	h_magic;	/* magic number for identification */
39};
40
41struct ext4_xattr_entry {
42	__u8	e_name_len;	/* length of name */
43	__u8	e_name_index;	/* attribute name index */
44	__le16	e_value_offs;	/* offset in disk block of value */
45	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
46	__le32	e_value_size;	/* size of attribute value */
47	__le32	e_hash;		/* hash value of name and value */
48	char	e_name[0];	/* attribute name */
49};
50
51#define EXT4_XATTR_PAD_BITS		2
52#define EXT4_XATTR_PAD		(1<<EXT4_XATTR_PAD_BITS)
53#define EXT4_XATTR_ROUND		(EXT4_XATTR_PAD-1)
54#define EXT4_XATTR_LEN(name_len) \
55	(((name_len) + EXT4_XATTR_ROUND + \
56	sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
57#define EXT4_XATTR_NEXT(entry) \
58	((struct ext4_xattr_entry *)( \
59	 (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
60#define EXT4_XATTR_SIZE(size) \
61	(((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
62
63#define IHDR(inode, raw_inode) \
64	((struct ext4_xattr_ibody_header *) \
65		((void *)raw_inode + \
66		EXT4_GOOD_OLD_INODE_SIZE + \
67		EXT4_I(inode)->i_extra_isize))
68#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
69
70#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
71#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
72#define BFIRST(bh) ENTRY(BHDR(bh)+1)
73#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
74
75#define EXT4_ZERO_XATTR_VALUE ((void *)-1)
76
77struct ext4_xattr_info {
78	int name_index;
79	const char *name;
80	const void *value;
81	size_t value_len;
82};
83
84struct ext4_xattr_search {
85	struct ext4_xattr_entry *first;
86	void *base;
87	void *end;
88	struct ext4_xattr_entry *here;
89	int not_found;
90};
91
92struct ext4_xattr_ibody_find {
93	struct ext4_xattr_search s;
94	struct ext4_iloc iloc;
95};
96
97extern const struct xattr_handler ext4_xattr_user_handler;
98extern const struct xattr_handler ext4_xattr_trusted_handler;
99extern const struct xattr_handler ext4_xattr_security_handler;
100
101extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
102
103extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
104extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
105extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
106
107extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
108extern void ext4_xattr_put_super(struct super_block *);
109
110extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
111			    struct ext4_inode *raw_inode, handle_t *handle);
112
113extern const struct xattr_handler *ext4_xattr_handlers[];
114
115extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
116				 struct ext4_xattr_ibody_find *is);
117extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
118				const char *name,
119				void *buffer, size_t buffer_size);
120extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
121				       struct ext4_xattr_info *i,
122				       struct ext4_xattr_ibody_find *is);
123
124extern struct mb_cache *ext4_xattr_create_cache(char *name);
125extern void ext4_xattr_destroy_cache(struct mb_cache *);
126
127#ifdef CONFIG_EXT4_FS_SECURITY
128extern int ext4_init_security(handle_t *handle, struct inode *inode,
129			      struct inode *dir, const struct qstr *qstr);
130#else
131static inline int ext4_init_security(handle_t *handle, struct inode *inode,
132				     struct inode *dir, const struct qstr *qstr)
133{
134	return 0;
135}
136#endif
137