| Denis Vlasenko | c4f623e | 2006-12-26 01:30:59 +0000 | [diff] [blame] | 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 | |
| 64 | } journal_superblock_t; |
| 65 | |