fs/ext2/xattr.h

   1 /*
   2   File: linux/ext2_xattr.h
   3
   4   On-disk format of extended attributes for the ext2 filesystem.
   5
   6   (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
   7 */
   8
   9 #include <linux/init.h>
  10 #include <linux/xattr.h>
  11
  12 /* Magic value in attribute blocks */
  13 #define EXT2_XATTR_MAGIC                0xEA020000
  14
  15 /* Maximum number of references to one attribute block */
  16 #define EXT2_XATTR_REFCOUNT_MAX         1024
  17
  18 /* Name indexes */
  19 #define EXT2_XATTR_INDEX_USER                   1
  20 #define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS       2
  21 #define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT      3
  22 #define EXT2_XATTR_INDEX_TRUSTED                4
  23 #define EXT2_XATTR_INDEX_LUSTRE                 5
  24 #define EXT2_XATTR_INDEX_SECURITY               6
  25
  26 struct ext2_xattr_header {
  27         __le32  h_magic;        /* magic number for identification */
  28         __le32  h_refcount;     /* reference count */
  29         __le32  h_blocks;       /* number of disk blocks used */
  30         __le32  h_hash;         /* hash value of all attributes */
  31         __u32   h_reserved[4];  /* zero right now */
  32 };
  33
  34 struct ext2_xattr_entry {
  35         __u8    e_name_len;     /* length of name */
  36         __u8    e_name_index;   /* attribute name index */
  37         __le16  e_value_offs;   /* offset in disk block of value */
  38         __le32  e_value_block;  /* disk block attribute is stored on (n/i) */
  39         __le32  e_value_size;   /* size of attribute value */
  40         __le32  e_hash;         /* hash value of name and value */
  41         char    e_name[0];      /* attribute name */
  42 };
  43
  44 #define EXT2_XATTR_PAD_BITS             2
  45 #define EXT2_XATTR_PAD          (1<<EXT2_XATTR_PAD_BITS)
  46 #define EXT2_XATTR_ROUND                (EXT2_XATTR_PAD-1)
  47 #define EXT2_XATTR_LEN(name_len) \
  48         (((name_len) + EXT2_XATTR_ROUND + \
  49         sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
  50 #define EXT2_XATTR_NEXT(entry) \
  51         ( (struct ext2_xattr_entry *)( \
  52           (char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
  53 #define EXT2_XATTR_SIZE(size) \
  54         (((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
  55
  56 struct mb_cache;
  57
  58 # ifdef CONFIG_EXT2_FS_XATTR
  59
  60 extern const struct xattr_handler ext2_xattr_user_handler;
  61 extern const struct xattr_handler ext2_xattr_trusted_handler;
  62 extern const struct xattr_handler ext2_xattr_security_handler;
  63
  64 extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
  65
  66 extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
  67 extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
  68
  69 extern void ext2_xattr_delete_inode(struct inode *);
  70
  71 extern struct mb_cache *ext2_xattr_create_cache(void);
  72 extern void ext2_xattr_destroy_cache(struct mb_cache *cache);
  73
  74 extern const struct xattr_handler *ext2_xattr_handlers[];
  75
  76 # else  /* CONFIG_EXT2_FS_XATTR */
  77
  78 static inline int
  79 ext2_xattr_get(struct inode *inode, int name_index,
  80                const char *name, void *buffer, size_t size)
  81 {
  82         return -EOPNOTSUPP;
  83 }
  84
  85 static inline int
  86 ext2_xattr_set(struct inode *inode, int name_index, const char *name,
  87                const void *value, size_t size, int flags)
  88 {
  89         return -EOPNOTSUPP;
  90 }
  91
  92 static inline void
  93 ext2_xattr_delete_inode(struct inode *inode)
  94 {
  95 }
  96
  97 static inline void ext2_xattr_destroy_cache(struct mb_cache *cache)
  98 {
  99 }
 100
 101 #define ext2_xattr_handlers NULL
 102
 103 # endif  /* CONFIG_EXT2_FS_XATTR */
 104
 105 #ifdef CONFIG_EXT2_FS_SECURITY
 106 extern int ext2_init_security(struct inode *inode, struct inode *dir,
 107                               const struct qstr *qstr);
 108 #else
 109 static inline int ext2_init_security(struct inode *inode, struct inode *dir,
 110                                      const struct qstr *qstr)
 111 {
 112         return 0;
 113 }
 114 #endif