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

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * jfs_dat.h --- stripped down header file which only contains the JFS
   4  *      on-disk data structures
   5  */
   6
   7 #define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
   8
   9 /*
  10  * On-disk structures
  11  */
  12
  13 /*
  14  * Descriptor block types:
  15  */
  16
  17 #define JFS_DESCRIPTOR_BLOCK    1
  18 #define JFS_COMMIT_BLOCK        2
  19 #define JFS_SUPERBLOCK          3
  20
  21 /*
  22  * Standard header for all descriptor blocks:
  23  */
  24 typedef struct journal_header_s
  25 {
  26         __u32           h_magic;
  27         __u32           h_blocktype;
  28         __u32           h_sequence;
  29 } journal_header_t;
  30
  31
  32 /*
  33  * The block tag: used to describe a single buffer in the journal
  34  */
  35 typedef struct journal_block_tag_s
  36 {
  37         __u32           t_blocknr;      /* The on-disk block number */
  38         __u32           t_flags;        /* See below */
  39 } journal_block_tag_t;
  40
  41 /* Definitions for the journal tag flags word: */
  42 #define JFS_FLAG_ESCAPE         1       /* on-disk block is escaped */
  43 #define JFS_FLAG_SAME_UUID      2       /* block has same uuid as previous */
  44 #define JFS_FLAG_DELETED        4       /* block deleted by this transaction */
  45 #define JFS_FLAG_LAST_TAG       8       /* last tag in this descriptor block */
  46
  47
  48 /*
  49  * The journal superblock
  50  */
  51 typedef struct journal_superblock_s
  52 {
  53         journal_header_t s_header;
  54
  55         /* Static information describing the journal */
  56         __u32           s_blocksize;    /* journal device blocksize */
  57         __u32           s_maxlen;       /* total blocks in journal file */
  58         __u32           s_first;        /* first block of log information */
  59
  60         /* Dynamic information describing the current state of the log */
  61         __u32           s_sequence;     /* first commit ID expected in log */
  62         __u32           s_start;        /* blocknr of start of log */
  63 } journal_superblock_t;