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
39struct 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
45struct 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
109extern const struct xattr_handler f2fs_xattr_user_handler;
110extern const struct xattr_handler f2fs_xattr_trusted_handler;
111extern const struct xattr_handler f2fs_xattr_advise_handler;
112extern const struct xattr_handler f2fs_xattr_security_handler;
113
114extern const struct xattr_handler *f2fs_xattr_handlers[];
115
116extern int f2fs_setxattr(struct inode *, int, const char *,
117				const void *, size_t, struct page *, int);
118extern int f2fs_getxattr(struct inode *, int, const char *, void *,
119						size_t, struct page *);
120extern ssize_t f2fs_listxattr(struct dentry *, char *, size_t);
121#else
122
123#define f2fs_xattr_handlers	NULL
124static inline int f2fs_setxattr(struct inode *inode, int index,
125		const char *name, const void *value, size_t size, int flags)
126{
127	return -EOPNOTSUPP;
128}
129static inline int f2fs_getxattr(struct inode *inode, int index,
130			const char *name, void *buffer,
131			size_t buffer_size, struct page *dpage)
132{
133	return -EOPNOTSUPP;
134}
135static inline ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
136		size_t buffer_size)
137{
138	return -EOPNOTSUPP;
139}
140#endif
141
142#ifdef CONFIG_F2FS_FS_SECURITY
143extern int f2fs_init_security(struct inode *, struct inode *,
144				const struct qstr *, struct page *);
145#else
146static inline int f2fs_init_security(struct inode *inode, struct inode *dir,
147				const struct qstr *qstr, struct page *ipage)
148{
149	return 0;
150}
151#endif
152#endif /* __F2FS_XATTR_H__ */
153