1/*- 2 * modified for EXT2FS support in Lites 1.1 3 * 4 * Aug 1995, Godmar Back (gback@cs.utah.edu) 5 * University of Utah, Department of Computer Science 6 */ 7/*- 8 * SPDX-License-Identifier: BSD-3-Clause 9 * 10 * Copyright (c) 1982, 1986, 1993 11 * The Regents of the University of California. All rights reserved. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 */ 37 38#ifndef _FS_EXT2FS_FS_H_ 39#define _FS_EXT2FS_FS_H_ 40 41/* 42 * Each disk drive contains some number of file systems. 43 * A file system consists of a number of cylinder groups. 44 * Each cylinder group has inodes and data. 45 * 46 * A file system is described by its super-block, which in turn 47 * describes the cylinder groups. The super-block is critical 48 * data and is replicated in each cylinder group to protect against 49 * catastrophic loss. This is done at `newfs' time and the critical 50 * super-block data does not change, so the copies need not be 51 * referenced further unless disaster strikes. 52 * 53 * The first boot and super blocks are given in absolute disk addresses. 54 * The byte-offset forms are preferred, as they don't imply a sector size. 55 */ 56#define SBLOCK 0 57#define SBLOCKSIZE 1024 58#define SBLOCKOFFSET 1024 59#define SBLOCKBLKSIZE 4096 60 61/* 62 * The path name on which the file system is mounted is maintained 63 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in 64 * the super block for this name. 65 */ 66#define MAXMNTLEN 512 67 68/* 69 * A summary of contiguous blocks of various sizes is maintained 70 * in each cylinder group. Normally this is set by the initial 71 * value of fs_maxcontig. 72 * 73 * XXX:FS_MAXCONTIG is set to 16 to conserve space. Here we set 74 * EXT2_MAXCONTIG to 32 for better performance. 75 */ 76#define EXT2_MAXCONTIG 32 77 78/* 79 * Grigoriy Orlov <gluk@ptci.ru> has done some extensive work to fine 80 * tune the layout preferences for directories within a filesystem. 81 * His algorithm can be tuned by adjusting the following parameters 82 * which tell the system the average file size and the average number 83 * of files per directory. These defaults are well selected for typical 84 * filesystems, but may need to be tuned for odd cases like filesystems 85 * being used for squid caches or news spools. 86 * AVFPDIR is the expected number of files per directory. AVGDIRSIZE is 87 * obtained by multiplying AVFPDIR and AVFILESIZ which is assumed to be 88 * 16384. 89 */ 90 91#define AFPDIR 64 92#define AVGDIRSIZE 1048576 93 94/* 95 * Macros for access to superblock array structures 96 */ 97 98/* 99 * Turn file system block numbers into disk block addresses. 100 * This maps file system blocks to device size blocks. 101 */ 102#define fsbtodb(fs, b) ((daddr_t)(b) << (fs)->e2fs_fsbtodb) 103#define dbtofsb(fs, b) ((b) >> (fs)->e2fs_fsbtodb) 104 105/* get group containing inode */ 106#define ino_to_cg(fs, x) (((x) - 1) / (fs->e2fs_ipg)) 107 108/* get block containing inode from its number x */ 109#define ino_to_fsba(fs, x) \ 110 (e2fs_gd_get_i_tables(&(fs)->e2fs_gd[ino_to_cg((fs), (x))]) + \ 111 (((x) - 1) % (fs)->e2fs_ipg) / (fs)->e2fs_ipb) 112 113/* get offset for inode in block */ 114#define ino_to_fsbo(fs, x) ((x-1) % (fs->e2fs_ipb)) 115 116/* 117 * Give cylinder group number for a file system block. 118 * Give cylinder group block number for a file system block. 119 */ 120#define dtog(fs, d) (((d) - le32toh(fs->e2fs->e2fs_first_dblock)) / \ 121 EXT2_BLOCKS_PER_GROUP(fs)) 122#define dtogd(fs, d) (((d) - le32toh(fs->e2fs->e2fs_first_dblock)) % \ 123 EXT2_BLOCKS_PER_GROUP(fs)) 124 125/* 126 * The following macros optimize certain frequently calculated 127 * quantities by using shifts and masks in place of divisions 128 * modulos and multiplications. 129 */ 130#define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \ 131 ((loc) & (fs)->e2fs_qbmask) 132 133#define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \ 134 ((blk) << (fs->e2fs_bshift)) 135 136#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \ 137 ((loc) >> (fs->e2fs_bshift)) 138 139/* no fragments -> logical block number equal # of frags */ 140#define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \ 141 ((loc) >> (fs->e2fs_bshift)) 142 143#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \ 144 roundup(size, fs->e2fs_fsize) 145 /* was (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) */ 146 147/* 148 * Determining the size of a file block in the file system. 149 * easy w/o fragments 150 */ 151#define blksize(fs, ip, lbn) ((fs)->e2fs_fsize) 152 153/* 154 * INOPB is the number of inodes in a secondary storage block. 155 */ 156#define INOPB(fs) (fs->e2fs_ipb) 157 158/* 159 * NINDIR is the number of indirects in a file system block. 160 */ 161#define NINDIR(fs) (EXT2_ADDR_PER_BLOCK(fs)) 162 163/* 164 * Use if additional debug logging is required. 165 */ 166/* #define EXT2FS_PRINT_EXTENTS */ 167 168#endif /* !_FS_EXT2FS_FS_H_ */ 169