Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * include/linux/journal-head.h | |
3 | * | |
4 | * buffer_head fields for JBD | |
5 | * | |
e1f8e874 | 6 | * 27 May 2001 Andrew Morton |
1da177e4 LT |
7 | * Created - pulled out of fs.h |
8 | */ | |
9 | ||
10 | #ifndef JOURNAL_HEAD_H_INCLUDED | |
11 | #define JOURNAL_HEAD_H_INCLUDED | |
12 | ||
13 | typedef unsigned int tid_t; /* Unique transaction ID */ | |
14 | typedef struct transaction_s transaction_t; /* Compound transaction type */ | |
e06c8227 JB |
15 | |
16 | ||
1da177e4 LT |
17 | struct buffer_head; |
18 | ||
19 | struct journal_head { | |
20 | /* | |
21 | * Points back to our buffer_head. [jbd_lock_bh_journal_head()] | |
22 | */ | |
23 | struct buffer_head *b_bh; | |
24 | ||
25 | /* | |
26 | * Reference count - see description in journal.c | |
27 | * [jbd_lock_bh_journal_head()] | |
28 | */ | |
29 | int b_jcount; | |
30 | ||
31 | /* | |
32 | * Journalling list for this buffer [jbd_lock_bh_state()] | |
33 | */ | |
34 | unsigned b_jlist; | |
35 | ||
36 | /* | |
37 | * This flag signals the buffer has been modified by | |
38 | * the currently running transaction | |
39 | * [jbd_lock_bh_state()] | |
40 | */ | |
41 | unsigned b_modified; | |
42 | ||
c2cc7028 AG |
43 | /* |
44 | * This feild tracks the last transaction id in which this buffer | |
45 | * has been cowed | |
46 | * [jbd_lock_bh_state()] | |
47 | */ | |
5cf49d76 | 48 | tid_t b_cow_tid; |
c2cc7028 | 49 | |
1da177e4 LT |
50 | /* |
51 | * Copy of the buffer data frozen for writing to the log. | |
52 | * [jbd_lock_bh_state()] | |
53 | */ | |
54 | char *b_frozen_data; | |
55 | ||
56 | /* | |
57 | * Pointer to a saved copy of the buffer containing no uncommitted | |
58 | * deallocation references, so that allocations can avoid overwriting | |
59 | * uncommitted deletes. [jbd_lock_bh_state()] | |
60 | */ | |
61 | char *b_committed_data; | |
62 | ||
63 | /* | |
64 | * Pointer to the compound transaction which owns this buffer's | |
65 | * metadata: either the running transaction or the committing | |
66 | * transaction (if there is one). Only applies to buffers on a | |
67 | * transaction's data or metadata journaling list. | |
68 | * [j_list_lock] [jbd_lock_bh_state()] | |
932bb305 JK |
69 | * Either of these locks is enough for reading, both are needed for |
70 | * changes. | |
1da177e4 LT |
71 | */ |
72 | transaction_t *b_transaction; | |
73 | ||
74 | /* | |
75 | * Pointer to the running compound transaction which is currently | |
76 | * modifying the buffer's metadata, if there was already a transaction | |
77 | * committing it when the new transaction touched it. | |
78 | * [t_list_lock] [jbd_lock_bh_state()] | |
79 | */ | |
80 | transaction_t *b_next_transaction; | |
81 | ||
82 | /* | |
83 | * Doubly-linked list of buffers on a transaction's data, metadata or | |
84 | * forget queue. [t_list_lock] [jbd_lock_bh_state()] | |
85 | */ | |
86 | struct journal_head *b_tnext, *b_tprev; | |
87 | ||
88 | /* | |
89 | * Pointer to the compound transaction against which this buffer | |
90 | * is checkpointed. Only dirty buffers can be checkpointed. | |
91 | * [j_list_lock] | |
92 | */ | |
93 | transaction_t *b_cp_transaction; | |
94 | ||
95 | /* | |
96 | * Doubly-linked list of buffers still remaining to be flushed | |
97 | * before an old transaction can be checkpointed. | |
98 | * [j_list_lock] | |
99 | */ | |
100 | struct journal_head *b_cpnext, *b_cpprev; | |
e06c8227 JB |
101 | |
102 | /* Trigger type */ | |
103 | struct jbd2_buffer_trigger_type *b_triggers; | |
104 | ||
105 | /* Trigger type for the committing transaction's frozen data */ | |
106 | struct jbd2_buffer_trigger_type *b_frozen_triggers; | |
1da177e4 LT |
107 | }; |
108 | ||
109 | #endif /* JOURNAL_HEAD_H_INCLUDED */ |