64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
/* 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;
|