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 * Copyright (c) 1982, 1986, 1993 9 * The Regents of the University of California. All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)fs.h 8.7 (Berkeley) 4/19/94 36 * $FreeBSD$ 37 */ 38 39 /* 40 * Each disk drive contains some number of file systems. 41 * A file system consists of a number of cylinder groups. 42 * Each cylinder group has inodes and data. 43 * 44 * A file system is described by its super-block, which in turn 45 * describes the cylinder groups. The super-block is critical 46 * data and is replicated in each cylinder group to protect against 47 * catastrophic loss. This is done at `newfs' time and the critical 48 * super-block data does not change, so the copies need not be 49 * referenced further unless disaster strikes. 50 * 51 * The first boot and super blocks are given in absolute disk addresses. 52 * The byte-offset forms are preferred, as they don't imply a sector size. 53 */ 54 #define SBSIZE 1024 55 #define SBLOCK 2 56 57 /* 58 * The path name on which the file system is mounted is maintained 59 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in 60 * the super block for this name. 61 */ 62 #define MAXMNTLEN 512 63 64 /* 65 * Grigoriy Orlov <gluk@ptci.ru> has done some extensive work to fine 66 * tune the layout preferences for directories within a filesystem. 67 * His algorithm can be tuned by adjusting the following parameters 68 * which tell the system the average file size and the average number 69 * of files per directory. These defaults are well selected for typical 70 * filesystems, but may need to be tuned for odd cases like filesystems 71 * being used for squid caches or news spools. 72 * AVFPDIR is the expected number of files per directory. AVGDIRSIZE is 73 * obtained by multiplying AVFPDIR and AVFILESIZ which is assumed to be 74 * 16384. 75 */ 76 77 #define AFPDIR 64 78 #define AVGDIRSIZE 1048576 79 80 /* 81 * Macros for access to superblock array structures 82 */ 83 84 /* 85 * Turn file system block numbers into disk block addresses. 86 * This maps file system blocks to device size blocks. 87 */ 88 #define fsbtodb(fs, b) ((b) << ((fs)->e2fs_fsbtodb)) 89 #define dbtofsb(fs, b) ((b) >> ((fs)->e2fs_fsbtodb)) 90 91 /* get group containing inode */ 92 #define ino_to_cg(fs, x) (((x) - 1) / (fs->e2fs_ipg)) 93 94 /* get block containing inode from its number x */ 95 #define ino_to_fsba(fs, x) \ 96 ((fs)->e2fs_gd[ino_to_cg((fs), (x))].ext2bgd_i_tables + \ 97 (((x) - 1) % (fs)->e2fs->e2fs_ipg) / (fs)->e2fs_ipb) 98 99 /* get offset for inode in block */ 100 #define ino_to_fsbo(fs, x) ((x-1) % (fs->e2fs_ipb)) 101 102 /* 103 * Give cylinder group number for a file system block. 104 * Give cylinder group block number for a file system block. 105 */ 106 #define dtog(fs, d) (((d) - fs->e2fs->e2fs_first_dblock) / \ 107 EXT2_BLOCKS_PER_GROUP(fs)) 108 #define dtogd(fs, d) (((d) - fs->e2fs->e2fs_first_dblock) % \ 109 EXT2_BLOCKS_PER_GROUP(fs)) 110 111 /* 112 * The following macros optimize certain frequently calculated 113 * quantities by using shifts and masks in place of divisions 114 * modulos and multiplications. 115 */ 116 #define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \ 117 ((loc) & (fs)->e2fs_qbmask) 118 119 #define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \ 120 ((blk) << (fs->e2fs_bshift)) 121 122 #define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \ 123 ((loc) >> (fs->e2fs_bshift)) 124 125 /* no fragments -> logical block number equal # of frags */ 126 #define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \ 127 ((loc) >> (fs->e2fs_bshift)) 128 129 #define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \ 130 roundup(size, fs->e2fs_fsize) 131 /* was (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) */ 132 133 /* 134 * Determining the size of a file block in the file system. 135 * easy w/o fragments 136 */ 137 #define blksize(fs, ip, lbn) ((fs)->e2fs_fsize) 138 139 /* 140 * INOPB is the number of inodes in a secondary storage block. 141 */ 142 #define INOPB(fs) (fs->e2fs_ipb) 143 144 /* 145 * NINDIR is the number of indirects in a file system block. 146 */ 147 #define NINDIR(fs) (EXT2_ADDR_PER_BLOCK(fs)) 148 149 extern int inside[], around[]; 150 extern u_char *fragtbl[]; 151 152 153