release/src/router/busybox/e2fsprogs/ext2fs/ext2_ext_attr.h

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3   File: linux/ext2_ext_attr.h
   4
   5   On-disk format of extended attributes for the ext2 filesystem.
   6
   7   (C) 2000 Andreas Gruenbacher, <a.gruenbacher@computer.org>
   8 */
   9
  10 /* Magic value in attribute blocks */
  11 #define EXT2_EXT_ATTR_MAGIC_v1          0xEA010000
  12 #define EXT2_EXT_ATTR_MAGIC             0xEA020000
  13
  14 /* Maximum number of references to one attribute block */
  15 #define EXT2_EXT_ATTR_REFCOUNT_MAX      1024
  16
  17 struct ext2_ext_attr_header {
  18         __u32   h_magic;        /* magic number for identification */
  19         __u32   h_refcount;     /* reference count */
  20         __u32   h_blocks;       /* number of disk blocks used */
  21         __u32   h_hash;         /* hash value of all attributes */
  22         __u32   h_reserved[4];  /* zero right now */
  23 };
  24
  25 struct ext2_ext_attr_entry {
  26         __u8    e_name_len;     /* length of name */
  27         __u8    e_name_index;   /* attribute name index */
  28         __u16   e_value_offs;   /* offset in disk block of value */
  29         __u32   e_value_block;  /* disk block attribute is stored on (n/i) */
  30         __u32   e_value_size;   /* size of attribute value */
  31         __u32   e_hash;         /* hash value of name and value */
  32 };
  33
  34 #define EXT2_EXT_ATTR_PAD_BITS          2
  35 #define EXT2_EXT_ATTR_PAD               (1<<EXT2_EXT_ATTR_PAD_BITS)
  36 #define EXT2_EXT_ATTR_ROUND             (EXT2_EXT_ATTR_PAD-1)
  37 #define EXT2_EXT_ATTR_LEN(name_len) \
  38         (((name_len) + EXT2_EXT_ATTR_ROUND + \
  39         sizeof(struct ext2_ext_attr_entry)) & ~EXT2_EXT_ATTR_ROUND)
  40 #define EXT2_EXT_ATTR_NEXT(entry) \
  41         ( (struct ext2_ext_attr_entry *)( \
  42           (char *)(entry) + EXT2_EXT_ATTR_LEN((entry)->e_name_len)) )
  43 #define EXT2_EXT_ATTR_SIZE(size) \
  44         (((size) + EXT2_EXT_ATTR_ROUND) & ~EXT2_EXT_ATTR_ROUND)
  45 #define EXT2_EXT_IS_LAST_ENTRY(entry) (*((__u32 *)(entry)) == 0UL)
  46 #define EXT2_EXT_ATTR_NAME(entry) \
  47         (((char *) (entry)) + sizeof(struct ext2_ext_attr_entry))
  48 #define EXT2_XATTR_LEN(name_len) \
  49         (((name_len) + EXT2_EXT_ATTR_ROUND + \
  50         sizeof(struct ext2_xattr_entry)) & ~EXT2_EXT_ATTR_ROUND)
  51 #define EXT2_XATTR_SIZE(size) \
  52         (((size) + EXT2_EXT_ATTR_ROUND) & ~EXT2_EXT_ATTR_ROUND)