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/* vi: set sw=4 ts=4: */
/*
* jfs_dat.h --- stripped down header file which only contains the JFS
* on-disk data structures
*/
#define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
/*
* On-disk structures
*/
/*
* Descriptor block types:
*/
#define JFS_DESCRIPTOR_BLOCK 1
#define JFS_COMMIT_BLOCK 2
#define JFS_SUPERBLOCK 3
/*
* Standard header for all descriptor blocks:
*/
typedef struct journal_header_s
{
__u32 h_magic;
__u32 h_blocktype;
__u32 h_sequence;
} journal_header_t;
/*
* The block tag: used to describe a single buffer in the journal
*/
typedef struct journal_block_tag_s
{
__u32 t_blocknr; /* The on-disk block number */
__u32 t_flags; /* See below */
} journal_block_tag_t;
/* Definitions for the journal tag flags word: */
#define JFS_FLAG_ESCAPE 1 /* on-disk block is escaped */
#define JFS_FLAG_SAME_UUID 2 /* block has same uuid as previous */
#define JFS_FLAG_DELETED 4 /* block deleted by this transaction */
#define JFS_FLAG_LAST_TAG 8 /* last tag in this descriptor block */
/*
* The journal superblock
*/
typedef struct journal_superblock_s
{
journal_header_t s_header;
/* Static information describing the journal */
__u32 s_blocksize; /* journal device blocksize */
__u32 s_maxlen; /* total blocks in journal file */
__u32 s_first; /* first block of log information */
/* Dynamic information describing the current state of the log */
__u32 s_sequence; /* first commit ID expected in log */
__u32 s_start; /* blocknr of start of log */
} journal_superblock_t;
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