*/
int journal_start_transaction(journal *jnl);
int journal_modify_block_start(journal *jnl, struct buf *bp);
int journal_modify_block_abort(journal *jnl, struct buf *bp);
int journal_modify_block_end(journal *jnl, struct buf *bp, void (*func)(struct buf *bp, void *arg), void *arg);
int journal_kill_block(journal *jnl, struct buf *bp);
*/
int journal_start_transaction(journal *jnl);
int journal_modify_block_start(journal *jnl, struct buf *bp);
int journal_modify_block_abort(journal *jnl, struct buf *bp);
int journal_modify_block_end(journal *jnl, struct buf *bp, void (*func)(struct buf *bp, void *arg), void *arg);
int journal_kill_block(journal *jnl, struct buf *bp);