| /* 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; |
