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_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
  73 #define MIN_OFFSET      XATTR_ALIGN(PAGE_SIZE - \
  74                         sizeof(struct node_footer) - \
  75                         sizeof(__u32))
  76
  77 #define MAX_VALUE_LEN   (MIN_OFFSET - sizeof(struct f2fs_xattr_header) - \
  78                         sizeof(struct f2fs_xattr_entry))
  79
  80 /*
  81  * On-disk structure of f2fs_xattr
  82  * We use only 1 block for xattr.
  83  *
  84  * +--------------------+
  85  * | f2fs_xattr_header  |
  86  * |                    |
  87  * +--------------------+
  88  * | f2fs_xattr_entry   |
  89  * | .e_name_index = 1  |
  90  * | .e_name_len = 3    |
  91  * | .e_value_size = 14 |
  92  * | .e_name = "foo"    |
  93  * | "value_of_xattr"   |<- value_offs = e_name + e_name_len
  94  * +--------------------+
  95  * | f2fs_xattr_entry   |
  96  * | .e_name_index = 4  |
  97  * | .e_name = "bar"    |
  98  * +--------------------+
  99  * |                    |
 100  * |        Free        |
 101  * |                    |
 102  * +--------------------+<- MIN_OFFSET
 103  * |   node_footer      |
 104  * | (nid, ino, offset) |
 105  * +--------------------+
 106  *
 107  **/
 108
 109 #ifdef CONFIG_F2FS_FS_XATTR
 110 extern const struct xattr_handler f2fs_xattr_user_handler;
 111 extern const struct xattr_handler f2fs_xattr_trusted_handler;
 112 extern const struct xattr_handler f2fs_xattr_acl_access_handler;
 113 extern const struct xattr_handler f2fs_xattr_acl_default_handler;
 114 extern const struct xattr_handler f2fs_xattr_advise_handler;
 115
 116 extern const struct xattr_handler *f2fs_xattr_handlers[];
 117
 118 extern int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
 119                 const void *value, size_t value_len);
 120 extern int f2fs_getxattr(struct inode *inode, int name_index, const char *name,
 121                 void *buffer, size_t buffer_size);
 122 extern ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
 123                 size_t buffer_size);
 124
 125 #else
 126
 127 #define f2fs_xattr_handlers     NULL
 128 static inline int f2fs_setxattr(struct inode *inode, int name_index,
 129         const char *name, const void *value, size_t value_len)
 130 {
 131         return -EOPNOTSUPP;
 132 }
 133 static inline int f2fs_getxattr(struct inode *inode, int name_index,
 134                 const char *name, void *buffer, size_t buffer_size)
 135 {
 136         return -EOPNOTSUPP;
 137 }
 138 static inline ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
 139                 size_t buffer_size)
 140 {
 141         return -EOPNOTSUPP;
 142 }
 143 #endif
 144
 145 #endif /* __F2FS_XATTR_H__ */