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_NAME			"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
 43struct 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
 49struct 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
113extern const struct xattr_handler f2fs_xattr_user_handler;
114extern const struct xattr_handler f2fs_xattr_trusted_handler;
115extern const struct xattr_handler f2fs_xattr_advise_handler;
116extern const struct xattr_handler f2fs_xattr_security_handler;
117
118extern const struct xattr_handler *f2fs_xattr_handlers[];
119
120extern int f2fs_setxattr(struct inode *, int, const char *,
121				const void *, size_t, struct page *, int);
122extern int f2fs_getxattr(struct inode *, int, const char *, void *,
123						size_t, struct page *);
124extern ssize_t f2fs_listxattr(struct dentry *, char *, size_t);
125#else
126
127#define f2fs_xattr_handlers	NULL
128static inline int f2fs_setxattr(struct inode *inode, int index,
129		const char *name, const void *value, size_t size,
130		struct page *page, int flags)
131{
132	return -EOPNOTSUPP;
133}
134static inline int f2fs_getxattr(struct inode *inode, int index,
135			const char *name, void *buffer,
136			size_t buffer_size, struct page *dpage)
137{
138	return -EOPNOTSUPP;
139}
140static inline ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
141		size_t buffer_size)
142{
143	return -EOPNOTSUPP;
144}
145#endif
146
147#ifdef CONFIG_F2FS_FS_SECURITY
148extern int f2fs_init_security(struct inode *, struct inode *,
149				const struct qstr *, struct page *);
150#else
151static inline int f2fs_init_security(struct inode *inode, struct inode *dir,
152				const struct qstr *qstr, struct page *ipage)
153{
154	return 0;
155}
156#endif
157#endif /* __F2FS_XATTR_H__ */