2 * include/linux/journal-head.h
4 * buffer_head fields for JBD
6 * 27 May 2001 Andrew Morton <akpm@digeo.com>
7 * Created - pulled out of fs.h
10 #ifndef JOURNAL_HEAD_H_INCLUDED
11 #define JOURNAL_HEAD_H_INCLUDED
13 typedef unsigned int tid_t; /* Unique transaction ID */
14 typedef struct transaction_s transaction_t; /* Compound transaction type */
19 * Points back to our buffer_head. [jbd_lock_bh_journal_head()]
21 struct buffer_head *b_bh;
24 * Reference count - see description in journal.c
25 * [jbd_lock_bh_journal_head()]
30 * Journalling list for this buffer [jbd_lock_bh_state()]
35 * Copy of the buffer data frozen for writing to the log.
36 * [jbd_lock_bh_state()]
41 * Pointer to a saved copy of the buffer containing no uncommitted
42 * deallocation references, so that allocations can avoid overwriting
43 * uncommitted deletes. [jbd_lock_bh_state()]
45 char *b_committed_data;
48 * Pointer to the compound transaction which owns this buffer's
49 * metadata: either the running transaction or the committing
50 * transaction (if there is one). Only applies to buffers on a
51 * transaction's data or metadata journaling list.
52 * [j_list_lock] [jbd_lock_bh_state()]
54 transaction_t *b_transaction;
57 * Pointer to the running compound transaction which is currently
58 * modifying the buffer's metadata, if there was already a transaction
59 * committing it when the new transaction touched it.
60 * [t_list_lock] [jbd_lock_bh_state()]
62 transaction_t *b_next_transaction;
65 * Doubly-linked list of buffers on a transaction's data, metadata or
66 * forget queue. [t_list_lock] [jbd_lock_bh_state()]
68 struct journal_head *b_tnext, *b_tprev;
71 * Pointer to the compound transaction against which this buffer
72 * is checkpointed. Only dirty buffers can be checkpointed.
75 transaction_t *b_cp_transaction;
78 * Doubly-linked list of buffers still remaining to be flushed
79 * before an old transaction can be checkpointed.
82 struct journal_head *b_cpnext, *b_cpprev;
85 #endif /* JOURNAL_HEAD_H_INCLUDED */