LXR linux/fs/f2fs/xattr.h

   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, int flags)
 130{
 131        return -EOPNOTSUPP;
 132}
 133static 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}
 139static 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
 147extern int f2fs_init_security(struct inode *, struct inode *,
 148                                const struct qstr *, struct page *);
 149#else
 150static 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