xref: /linux/fs/ext4/xattr.h (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
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 
26 struct ext4_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 	__le32	h_checksum;	/* crc32c(uuid+id+xattrblock) */
32 				/* id = inum if refcount=1, blknum otherwise */
33 	__u32	h_reserved[3];	/* zero right now */
34 };
35 
36 struct ext4_xattr_ibody_header {
37 	__le32	h_magic;	/* magic number for identification */
38 };
39 
40 struct ext4_xattr_entry {
41 	__u8	e_name_len;	/* length of name */
42 	__u8	e_name_index;	/* attribute name index */
43 	__le16	e_value_offs;	/* offset in disk block of value */
44 	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
45 	__le32	e_value_size;	/* size of attribute value */
46 	__le32	e_hash;		/* hash value of name and value */
47 	char	e_name[0];	/* attribute name */
48 };
49 
50 #define EXT4_XATTR_PAD_BITS		2
51 #define EXT4_XATTR_PAD		(1<<EXT4_XATTR_PAD_BITS)
52 #define EXT4_XATTR_ROUND		(EXT4_XATTR_PAD-1)
53 #define EXT4_XATTR_LEN(name_len) \
54 	(((name_len) + EXT4_XATTR_ROUND + \
55 	sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
56 #define EXT4_XATTR_NEXT(entry) \
57 	((struct ext4_xattr_entry *)( \
58 	 (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
59 #define EXT4_XATTR_SIZE(size) \
60 	(((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
61 
62 #define IHDR(inode, raw_inode) \
63 	((struct ext4_xattr_ibody_header *) \
64 		((void *)raw_inode + \
65 		EXT4_GOOD_OLD_INODE_SIZE + \
66 		EXT4_I(inode)->i_extra_isize))
67 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
68 
69 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
70 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
71 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
72 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
73 
74 #define EXT4_ZERO_XATTR_VALUE ((void *)-1)
75 
76 struct ext4_xattr_info {
77 	int name_index;
78 	const char *name;
79 	const void *value;
80 	size_t value_len;
81 };
82 
83 struct ext4_xattr_search {
84 	struct ext4_xattr_entry *first;
85 	void *base;
86 	void *end;
87 	struct ext4_xattr_entry *here;
88 	int not_found;
89 };
90 
91 struct ext4_xattr_ibody_find {
92 	struct ext4_xattr_search s;
93 	struct ext4_iloc iloc;
94 };
95 
96 extern const struct xattr_handler ext4_xattr_user_handler;
97 extern const struct xattr_handler ext4_xattr_trusted_handler;
98 extern const struct xattr_handler ext4_xattr_acl_access_handler;
99 extern const struct xattr_handler ext4_xattr_acl_default_handler;
100 extern const struct xattr_handler ext4_xattr_security_handler;
101 
102 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
103 
104 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
105 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
106 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
107 
108 extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
109 extern void ext4_xattr_put_super(struct super_block *);
110 
111 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
112 			    struct ext4_inode *raw_inode, handle_t *handle);
113 
114 extern int __init ext4_init_xattr(void);
115 extern void ext4_exit_xattr(void);
116 
117 extern const struct xattr_handler *ext4_xattr_handlers[];
118 
119 extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
120 				 struct ext4_xattr_ibody_find *is);
121 extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
122 				const char *name,
123 				void *buffer, size_t buffer_size);
124 extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
125 				       struct ext4_xattr_info *i,
126 				       struct ext4_xattr_ibody_find *is);
127 
128 extern int ext4_has_inline_data(struct inode *inode);
129 extern int ext4_get_inline_size(struct inode *inode);
130 extern int ext4_get_max_inline_size(struct inode *inode);
131 extern int ext4_find_inline_data_nolock(struct inode *inode);
132 extern void ext4_write_inline_data(struct inode *inode,
133 				   struct ext4_iloc *iloc,
134 				   void *buffer, loff_t pos,
135 				   unsigned int len);
136 extern int ext4_prepare_inline_data(handle_t *handle, struct inode *inode,
137 				    unsigned int len);
138 extern int ext4_init_inline_data(handle_t *handle, struct inode *inode,
139 				 unsigned int len);
140 extern int ext4_destroy_inline_data(handle_t *handle, struct inode *inode);
141 
142 extern int ext4_readpage_inline(struct inode *inode, struct page *page);
143 extern int ext4_try_to_write_inline_data(struct address_space *mapping,
144 					 struct inode *inode,
145 					 loff_t pos, unsigned len,
146 					 unsigned flags,
147 					 struct page **pagep);
148 extern int ext4_write_inline_data_end(struct inode *inode,
149 				      loff_t pos, unsigned len,
150 				      unsigned copied,
151 				      struct page *page);
152 extern struct buffer_head *
153 ext4_journalled_write_inline_data(struct inode *inode,
154 				  unsigned len,
155 				  struct page *page);
156 extern int ext4_da_write_inline_data_begin(struct address_space *mapping,
157 					   struct inode *inode,
158 					   loff_t pos, unsigned len,
159 					   unsigned flags,
160 					   struct page **pagep,
161 					   void **fsdata);
162 extern int ext4_da_write_inline_data_end(struct inode *inode, loff_t pos,
163 					 unsigned len, unsigned copied,
164 					 struct page *page);
165 extern int ext4_try_add_inline_entry(handle_t *handle, struct dentry *dentry,
166 				     struct inode *inode);
167 extern int ext4_try_create_inline_dir(handle_t *handle,
168 				      struct inode *parent,
169 				      struct inode *inode);
170 extern int ext4_read_inline_dir(struct file *filp,
171 				void *dirent, filldir_t filldir,
172 				int *has_inline_data);
173 extern struct buffer_head *ext4_find_inline_entry(struct inode *dir,
174 					const struct qstr *d_name,
175 					struct ext4_dir_entry_2 **res_dir,
176 					int *has_inline_data);
177 extern int ext4_delete_inline_entry(handle_t *handle,
178 				    struct inode *dir,
179 				    struct ext4_dir_entry_2 *de_del,
180 				    struct buffer_head *bh,
181 				    int *has_inline_data);
182 extern int empty_inline_dir(struct inode *dir, int *has_inline_data);
183 extern struct buffer_head *ext4_get_first_inline_block(struct inode *inode,
184 					struct ext4_dir_entry_2 **parent_de,
185 					int *retval);
186 extern int ext4_inline_data_fiemap(struct inode *inode,
187 				   struct fiemap_extent_info *fieinfo,
188 				   int *has_inline);
189 extern int ext4_try_to_evict_inline_data(handle_t *handle,
190 					 struct inode *inode,
191 					 int needed);
192 extern void ext4_inline_data_truncate(struct inode *inode, int *has_inline);
193 
194 extern int ext4_convert_inline_data(struct inode *inode);
195 
196 #ifdef CONFIG_EXT4_FS_SECURITY
197 extern int ext4_init_security(handle_t *handle, struct inode *inode,
198 			      struct inode *dir, const struct qstr *qstr);
199 #else
200 static inline int ext4_init_security(handle_t *handle, struct inode *inode,
201 				     struct inode *dir, const struct qstr *qstr)
202 {
203 	return 0;
204 }
205 #endif
206