1 /* $NetBSD: wapbl_replay.h,v 1.2 2024/05/13 00:01:53 msaitoh 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 WAPBL_WC_HEADER = 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 wapbl_wc_header { 84 uint32_t wc_type; /* WAPBL_WC_HEADER log magic number */ 85 int32_t wc_len; /* length of this journal entry */ 86 uint32_t wc_checksum; 87 uint32_t wc_generation; 88 int32_t wc_fsid[2]; 89 uint64_t wc_time; 90 uint32_t wc_timensec; 91 uint32_t wc_version; 92 uint32_t wc_log_dev_bshift; 93 uint32_t wc_fs_dev_bshift; 94 int64_t wc_head; 95 int64_t wc_tail; 96 int64_t wc_circ_off; /* offset of circ buffer region */ 97 int64_t wc_circ_size; /* size of circular buffer region */ 98 uint8_t wc_spare[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