| 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 | |