2 * include/linux/journal-head.h
4 * buffer_head fields for JBD
6 * 27 May 2001 Andrew Morton
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 * This flag signals the buffer has been modified by
36 * the currently running transaction
37 * [jbd_lock_bh_state()]
42 * Copy of the buffer data frozen for writing to the log.
43 * [jbd_lock_bh_state()]
48 * Pointer to a saved copy of the buffer containing no uncommitted
49 * deallocation references, so that allocations can avoid overwriting
50 * uncommitted deletes. [jbd_lock_bh_state()]
52 char *b_committed_data;
55 * Pointer to the compound transaction which owns this buffer's
56 * metadata: either the running transaction or the committing
57 * transaction (if there is one). Only applies to buffers on a
58 * transaction's data or metadata journaling list.
59 * [j_list_lock] [jbd_lock_bh_state()]
61 transaction_t *b_transaction;
64 * Pointer to the running compound transaction which is currently
65 * modifying the buffer's metadata, if there was already a transaction
66 * committing it when the new transaction touched it.
67 * [t_list_lock] [jbd_lock_bh_state()]
69 transaction_t *b_next_transaction;
72 * Doubly-linked list of buffers on a transaction's data, metadata or
73 * forget queue. [t_list_lock] [jbd_lock_bh_state()]
75 struct journal_head *b_tnext, *b_tprev;
78 * Pointer to the compound transaction against which this buffer
79 * is checkpointed. Only dirty buffers can be checkpointed.
82 transaction_t *b_cp_transaction;
85 * Doubly-linked list of buffers still remaining to be flushed
86 * before an old transaction can be checkpointed.
89 struct journal_head *b_cpnext, *b_cpprev;
92 #endif /* JOURNAL_HEAD_H_INCLUDED */