1 | /* $NetBSD: wapbl_replay.h,v 1.1 2008/11/24 16:05:21 joerg Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c) 2003,2008 The NetBSD Foundation, Inc. |
5 | * All rights reserved. |
6 | * |
7 | * This code is derived from software contributed to The NetBSD Foundation |
8 | * by Wasabi Systems, Inc. |
9 | * |
10 | * Redistribution and use in source and binary forms, with or without |
11 | * modification, are permitted provided that the following conditions |
12 | * are met: |
13 | * 1. Redistributions of source code must retain the above copyright |
14 | * notice, this list of conditions and the following disclaimer. |
15 | * 2. Redistributions in binary form must reproduce the above copyright |
16 | * notice, this list of conditions and the following disclaimer in the |
17 | * documentation and/or other materials provided with the distribution. |
18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
29 | * POSSIBILITY OF SUCH DAMAGE. |
30 | */ |
31 | |
32 | #ifndef _SYS_WAPBL_REPLAY_H |
33 | #define _SYS_WAPBL_REPLAY_H |
34 | |
35 | #include <sys/types.h> |
36 | |
37 | /* The WAPBL journal layout. |
38 | * |
39 | * The journal consists of a header followed by a circular buffer |
40 | * region. The circular data area is described by the header |
41 | * wc_circ_off, wc_circ_size, wc_head and wc_tail fields as bytes |
42 | * from the start of the journal header. New records are inserted |
43 | * at wc_head and the oldest valid record can be found at wc_tail. |
44 | * When ((wc_head == wc_tail) && (wc_head == 0)), the journal is empty. |
45 | * The condition of ((wc_head == wc_tail) && (wc_head != 0)) |
46 | * indicates a full journal, although this condition is rare. |
47 | * |
48 | * The journal header as well as its records are marked by a 32bit |
49 | * type tag and length for ease of parsing. Journal records are |
50 | * padded so as to fall on journal device block boundaries. |
51 | */ |
52 | |
53 | /* |
54 | * The following are the 4 record types used by the journal: |
55 | * Each tag indicates journal data organized by one of the |
56 | * structures used below. |
57 | */ |
58 | enum { |
59 | = 0x5741424c, /* "WABL", struct wapbl_wc_header */ |
60 | WAPBL_WC_INODES, /* struct wapbl_wc_inodelist */ |
61 | WAPBL_WC_REVOCATIONS, /* struct wapbl_wc_blocklist */ |
62 | WAPBL_WC_BLOCKS, /* struct wapbl_wc_blocklist */ |
63 | }; |
64 | |
65 | /* null entry (on disk) */ |
66 | /* This structure isn't used directly, but shares its header |
67 | * layout with all the other log structures for the purpose |
68 | * of reading a log structure and determining its type |
69 | */ |
70 | struct wapbl_wc_null { |
71 | uint32_t wc_type; /* WAPBL_WC_* */ |
72 | int32_t wc_len; |
73 | uint8_t wc_spare[0]; /* actually longer */ |
74 | }; |
75 | |
76 | /* journal header (on-disk) |
77 | * This record is found at the start of the |
78 | * journal, but not within the circular buffer region. As well as |
79 | * describing the journal parameters and matching filesystem, it |
80 | * additionally serves as the atomic update record for journal |
81 | * updates. |
82 | */ |
83 | struct { |
84 | uint32_t ; /* WAPBL_WC_HEADER log magic number */ |
85 | int32_t ; /* length of this journal entry */ |
86 | uint32_t ; |
87 | uint32_t ; |
88 | int32_t [2]; |
89 | uint64_t ; |
90 | uint32_t ; |
91 | uint32_t ; |
92 | uint32_t ; |
93 | uint32_t ; |
94 | int64_t ; |
95 | int64_t ; |
96 | int64_t ; /* offset of of circ buffer region */ |
97 | int64_t ; /* size of circular buffer region */ |
98 | uint8_t [0]; /* actually longer */ |
99 | }; |
100 | |
101 | /* list of blocks (on disk) |
102 | * This record is used to describe a set of filesystem blocks, |
103 | * and is used with two type tags, WAPBL_WC_BLOCKS and |
104 | * WAPBL_WC_REVOCATIONS. |
105 | * |
106 | * For WAPBL_WC_BLOCKS, a copy of each listed block can be found |
107 | * starting at the next log device blocksize boundary. starting at |
108 | * one log device block since the start of the record. This contains |
109 | * the bulk of the filesystem journal data which is written using |
110 | * these records before being written into the filesystem. |
111 | * |
112 | * The WAPBL_WC_REVOCATIONS record is used to indicate that any |
113 | * previously listed blocks should not be written into the filesystem. |
114 | * This is important so that deallocated and reallocated data blocks |
115 | * do not get overwritten with stale data from the journal. The |
116 | * revocation records do not contain a copy of any actual block data. |
117 | */ |
118 | struct wapbl_wc_blocklist { |
119 | uint32_t wc_type; /* WAPBL_WC_{REVOCATIONS,BLOCKS} */ |
120 | int32_t wc_len; |
121 | int32_t wc_blkcount; |
122 | int32_t wc_unused; |
123 | struct { |
124 | int64_t wc_daddr; |
125 | int32_t wc_unused; |
126 | int32_t wc_dlen; |
127 | } wc_blocks[0]; /* actually longer */ |
128 | }; |
129 | |
130 | /* list of inodes (on disk) |
131 | * This record is used to describe the set of inodes which |
132 | * may be allocated but are unlinked. Inodes end up listed here |
133 | * while they are in the process of being initialized and |
134 | * deinitialized. Inodes unlinked while in use by a process |
135 | * will be listed here and the actual deletion must be completed |
136 | * on journal replay. |
137 | */ |
138 | struct wapbl_wc_inodelist { |
139 | uint32_t wc_type; /* WAPBL_WC_INODES */ |
140 | int32_t wc_len; |
141 | int32_t wc_inocnt; |
142 | int32_t wc_clear; /* set if previously listed inodes |
143 | hould be ignored */ |
144 | struct { |
145 | uint32_t wc_inumber; |
146 | uint32_t wc_imode; |
147 | } wc_inodes[0]; /* actually longer */ |
148 | }; |
149 | |
150 | #endif /* _SYS_WAPBL_REPLAY_H */ |
151 | |