xref: /openbmc/linux/fs/f2fs/xattr.h (revision ca55b2fe)
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 /* Should be same as EXT4_XATTR_INDEX_ENCRYPTION */
39 #define F2FS_XATTR_INDEX_ENCRYPTION		9
40 
41 #define F2FS_XATTR_NAME_ENCRYPTION_CONTEXT	"c"
42 
43 struct f2fs_xattr_header {
44 	__le32  h_magic;        /* magic number for identification */
45 	__le32  h_refcount;     /* reference count */
46 	__u32   h_reserved[4];  /* zero right now */
47 };
48 
49 struct f2fs_xattr_entry {
50 	__u8    e_name_index;
51 	__u8    e_name_len;
52 	__le16  e_value_size;   /* size of attribute value */
53 	char    e_name[0];      /* attribute name */
54 };
55 
56 #define XATTR_HDR(ptr)		((struct f2fs_xattr_header *)(ptr))
57 #define XATTR_ENTRY(ptr)	((struct f2fs_xattr_entry *)(ptr))
58 #define XATTR_FIRST_ENTRY(ptr)	(XATTR_ENTRY(XATTR_HDR(ptr) + 1))
59 #define XATTR_ROUND		(3)
60 
61 #define XATTR_ALIGN(size)	((size + XATTR_ROUND) & ~XATTR_ROUND)
62 
63 #define ENTRY_SIZE(entry) (XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + \
64 			entry->e_name_len + le16_to_cpu(entry->e_value_size)))
65 
66 #define XATTR_NEXT_ENTRY(entry)	((struct f2fs_xattr_entry *)((char *)(entry) +\
67 			ENTRY_SIZE(entry)))
68 
69 #define IS_XATTR_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
70 
71 #define list_for_each_xattr(entry, addr) \
72 		for (entry = XATTR_FIRST_ENTRY(addr);\
73 				!IS_XATTR_LAST_ENTRY(entry);\
74 				entry = XATTR_NEXT_ENTRY(entry))
75 
76 #define MIN_OFFSET(i)	XATTR_ALIGN(inline_xattr_size(i) + PAGE_SIZE -	\
77 				sizeof(struct node_footer) - sizeof(__u32))
78 
79 #define MAX_VALUE_LEN(i)	(MIN_OFFSET(i) -			\
80 				sizeof(struct f2fs_xattr_header) -	\
81 				sizeof(struct f2fs_xattr_entry))
82 
83 /*
84  * On-disk structure of f2fs_xattr
85  * We use inline xattrs space + 1 block for xattr.
86  *
87  * +--------------------+
88  * | f2fs_xattr_header  |
89  * |                    |
90  * +--------------------+
91  * | f2fs_xattr_entry   |
92  * | .e_name_index = 1  |
93  * | .e_name_len = 3    |
94  * | .e_value_size = 14 |
95  * | .e_name = "foo"    |
96  * | "value_of_xattr"   |<- value_offs = e_name + e_name_len
97  * +--------------------+
98  * | f2fs_xattr_entry   |
99  * | .e_name_index = 4  |
100  * | .e_name = "bar"    |
101  * +--------------------+
102  * |                    |
103  * |        Free        |
104  * |                    |
105  * +--------------------+<- MIN_OFFSET
106  * |   node_footer      |
107  * | (nid, ino, offset) |
108  * +--------------------+
109  *
110  **/
111 
112 #ifdef CONFIG_F2FS_FS_XATTR
113 extern const struct xattr_handler f2fs_xattr_user_handler;
114 extern const struct xattr_handler f2fs_xattr_trusted_handler;
115 extern const struct xattr_handler f2fs_xattr_advise_handler;
116 extern const struct xattr_handler f2fs_xattr_security_handler;
117 
118 extern const struct xattr_handler *f2fs_xattr_handlers[];
119 
120 extern int f2fs_setxattr(struct inode *, int, const char *,
121 				const void *, size_t, struct page *, int);
122 extern int f2fs_getxattr(struct inode *, int, const char *, void *,
123 						size_t, struct page *);
124 extern ssize_t f2fs_listxattr(struct dentry *, char *, size_t);
125 #else
126 
127 #define f2fs_xattr_handlers	NULL
128 static inline int f2fs_setxattr(struct inode *inode, int index,
129 		const char *name, const void *value, size_t size, int flags)
130 {
131 	return -EOPNOTSUPP;
132 }
133 static inline int f2fs_getxattr(struct inode *inode, int index,
134 			const char *name, void *buffer,
135 			size_t buffer_size, struct page *dpage)
136 {
137 	return -EOPNOTSUPP;
138 }
139 static inline ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
140 		size_t buffer_size)
141 {
142 	return -EOPNOTSUPP;
143 }
144 #endif
145 
146 #ifdef CONFIG_F2FS_FS_SECURITY
147 extern int f2fs_init_security(struct inode *, struct inode *,
148 				const struct qstr *, struct page *);
149 #else
150 static inline int f2fs_init_security(struct inode *inode, struct inode *dir,
151 				const struct qstr *qstr, struct page *ipage)
152 {
153 	return 0;
154 }
155 #endif
156 #endif /* __F2FS_XATTR_H__ */
157