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 */ | |
15 | struct buffer_head; | |
16 | ||
17 | struct journal_head { | |
18 | /* | |
19 | * Points back to our buffer_head. [jbd_lock_bh_journal_head()] | |
20 | */ | |
21 | struct buffer_head *b_bh; | |
22 | ||
23 | /* | |
24 | * Reference count - see description in journal.c | |
25 | * [jbd_lock_bh_journal_head()] | |
26 | */ | |
27 | int b_jcount; | |
28 | ||
29 | /* | |
30 | * Journalling list for this buffer [jbd_lock_bh_state()] | |
31 | */ | |
32 | unsigned b_jlist; | |
33 | ||
34 | /* | |
35 | * This flag signals the buffer has been modified by | |
36 | * the currently running transaction | |
37 | * [jbd_lock_bh_state()] | |
38 | */ | |
39 | unsigned b_modified; | |
40 | ||
41 | /* | |
42 | * Copy of the buffer data frozen for writing to the log. | |
43 | * [jbd_lock_bh_state()] | |
44 | */ | |
45 | char *b_frozen_data; | |
46 | ||
47 | /* | |
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()] | |
51 | */ | |
52 | char *b_committed_data; | |
53 | ||
54 | /* | |
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()] | |
60 | */ | |
61 | transaction_t *b_transaction; | |
62 | ||
63 | /* | |
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()] | |
68 | */ | |
69 | transaction_t *b_next_transaction; | |
70 | ||
71 | /* | |
72 | * Doubly-linked list of buffers on a transaction's data, metadata or | |
73 | * forget queue. [t_list_lock] [jbd_lock_bh_state()] | |
74 | */ | |
75 | struct journal_head *b_tnext, *b_tprev; | |
76 | ||
77 | /* | |
78 | * Pointer to the compound transaction against which this buffer | |
79 | * is checkpointed. Only dirty buffers can be checkpointed. | |
80 | * [j_list_lock] | |
81 | */ | |
82 | transaction_t *b_cp_transaction; | |
83 | ||
84 | /* | |
85 | * Doubly-linked list of buffers still remaining to be flushed | |
86 | * before an old transaction can be checkpointed. | |
87 | * [j_list_lock] | |
88 | */ | |
89 | struct journal_head *b_cpnext, *b_cpprev; | |
90 | }; | |
91 | ||
92 | #endif /* JOURNAL_HEAD_H_INCLUDED */ |