xref: /openbmc/linux/fs/f2fs/xattr.h (revision b34e08d5)
1 /*
2  * fs/f2fs/xattr.h
3  *
4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5  *             http://www.samsung.com/
6  *
7  * Portions of this code from linux/fs/ext2/xattr.h
8  *
9  * On-disk format of extended attributes for the ext2 filesystem.
10  *
11  * (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License version 2 as
15  * published by the Free Software Foundation.
16  */
17 #ifndef __F2FS_XATTR_H__
18 #define __F2FS_XATTR_H__
19 
20 #include <linux/init.h>
21 #include <linux/xattr.h>
22 
23 /* Magic value in attribute blocks */
24 #define F2FS_XATTR_MAGIC                0xF2F52011
25 
26 /* Maximum number of references to one attribute block */
27 #define F2FS_XATTR_REFCOUNT_MAX         1024
28 
29 /* Name indexes */
30 #define F2FS_SYSTEM_ADVISE_PREFIX		"system.advise"
31 #define F2FS_XATTR_INDEX_USER			1
32 #define F2FS_XATTR_INDEX_POSIX_ACL_ACCESS	2
33 #define F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT	3
34 #define F2FS_XATTR_INDEX_TRUSTED		4
35 #define F2FS_XATTR_INDEX_LUSTRE			5
36 #define F2FS_XATTR_INDEX_SECURITY		6
37 #define F2FS_XATTR_INDEX_ADVISE			7
38 
39 struct f2fs_xattr_header {
40 	__le32  h_magic;        /* magic number for identification */
41 	__le32  h_refcount;     /* reference count */
42 	__u32   h_reserved[4];  /* zero right now */
43 };
44 
45 struct f2fs_xattr_entry {
46 	__u8    e_name_index;
47 	__u8    e_name_len;
48 	__le16  e_value_size;   /* size of attribute value */
49 	char    e_name[0];      /* attribute name */
50 };
51 
52 #define XATTR_HDR(ptr)		((struct f2fs_xattr_header *)(ptr))
53 #define XATTR_ENTRY(ptr)	((struct f2fs_xattr_entry *)(ptr))
54 #define XATTR_FIRST_ENTRY(ptr)	(XATTR_ENTRY(XATTR_HDR(ptr) + 1))
55 #define XATTR_ROUND		(3)
56 
57 #define XATTR_ALIGN(size)	((size + XATTR_ROUND) & ~XATTR_ROUND)
58 
59 #define ENTRY_SIZE(entry) (XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + \
60 			entry->e_name_len + le16_to_cpu(entry->e_value_size)))
61 
62 #define XATTR_NEXT_ENTRY(entry)	((struct f2fs_xattr_entry *)((char *)(entry) +\
63 			ENTRY_SIZE(entry)))
64 
65 #define IS_XATTR_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
66 
67 #define list_for_each_xattr(entry, addr) \
68 		for (entry = XATTR_FIRST_ENTRY(addr);\
69 				!IS_XATTR_LAST_ENTRY(entry);\
70 				entry = XATTR_NEXT_ENTRY(entry))
71 
72 #define MIN_OFFSET(i)	XATTR_ALIGN(inline_xattr_size(i) + PAGE_SIZE -	\
73 				sizeof(struct node_footer) - sizeof(__u32))
74 
75 #define MAX_VALUE_LEN(i)	(MIN_OFFSET(i) -			\
76 				sizeof(struct f2fs_xattr_header) -	\
77 				sizeof(struct f2fs_xattr_entry))
78 
79 /*
80  * On-disk structure of f2fs_xattr
81  * We use inline xattrs space + 1 block for xattr.
82  *
83  * +--------------------+
84  * | f2fs_xattr_header  |
85  * |                    |
86  * +--------------------+
87  * | f2fs_xattr_entry   |
88  * | .e_name_index = 1  |
89  * | .e_name_len = 3    |
90  * | .e_value_size = 14 |
91  * | .e_name = "foo"    |
92  * | "value_of_xattr"   |<- value_offs = e_name + e_name_len
93  * +--------------------+
94  * | f2fs_xattr_entry   |
95  * | .e_name_index = 4  |
96  * | .e_name = "bar"    |
97  * +--------------------+
98  * |                    |
99  * |        Free        |
100  * |                    |
101  * +--------------------+<- MIN_OFFSET
102  * |   node_footer      |
103  * | (nid, ino, offset) |
104  * +--------------------+
105  *
106  **/
107 
108 #ifdef CONFIG_F2FS_FS_XATTR
109 extern const struct xattr_handler f2fs_xattr_user_handler;
110 extern const struct xattr_handler f2fs_xattr_trusted_handler;
111 extern const struct xattr_handler f2fs_xattr_advise_handler;
112 extern const struct xattr_handler f2fs_xattr_security_handler;
113 
114 extern const struct xattr_handler *f2fs_xattr_handlers[];
115 
116 extern int f2fs_setxattr(struct inode *, int, const char *,
117 				const void *, size_t, struct page *);
118 extern int f2fs_getxattr(struct inode *, int, const char *, void *, size_t);
119 extern ssize_t f2fs_listxattr(struct dentry *, char *, size_t);
120 #else
121 
122 #define f2fs_xattr_handlers	NULL
123 static inline int f2fs_setxattr(struct inode *inode, int name_index,
124 		const char *name, const void *value, size_t value_len)
125 {
126 	return -EOPNOTSUPP;
127 }
128 static inline int f2fs_getxattr(struct inode *inode, int name_index,
129 		const char *name, void *buffer, size_t buffer_size)
130 {
131 	return -EOPNOTSUPP;
132 }
133 static inline ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
134 		size_t buffer_size)
135 {
136 	return -EOPNOTSUPP;
137 }
138 #endif
139 
140 #ifdef CONFIG_F2FS_FS_SECURITY
141 extern int f2fs_init_security(struct inode *, struct inode *,
142 				const struct qstr *, struct page *);
143 #else
144 static inline int f2fs_init_security(struct inode *inode, struct inode *dir,
145 				const struct qstr *qstr, struct page *ipage)
146 {
147 	return 0;
148 }
149 #endif
150 #endif /* __F2FS_XATTR_H__ */
151