1139778Simp/*- 212115Sdyson * modified for EXT2FS support in Lites 1.1 312115Sdyson * 412115Sdyson * Aug 1995, Godmar Back (gback@cs.utah.edu) 512115Sdyson * University of Utah, Department of Computer Science 612115Sdyson */ 7139778Simp/*- 812115Sdyson * Copyright (c) 1982, 1986, 1993 912115Sdyson * The Regents of the University of California. All rights reserved. 1012115Sdyson * 1112115Sdyson * Redistribution and use in source and binary forms, with or without 1212115Sdyson * modification, are permitted provided that the following conditions 1312115Sdyson * are met: 1412115Sdyson * 1. Redistributions of source code must retain the above copyright 1512115Sdyson * notice, this list of conditions and the following disclaimer. 1612115Sdyson * 2. Redistributions in binary form must reproduce the above copyright 1712115Sdyson * notice, this list of conditions and the following disclaimer in the 1812115Sdyson * documentation and/or other materials provided with the distribution. 1912115Sdyson * 4. Neither the name of the University nor the names of its contributors 2012115Sdyson * may be used to endorse or promote products derived from this software 2112115Sdyson * without specific prior written permission. 2212115Sdyson * 2312115Sdyson * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 2412115Sdyson * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2512115Sdyson * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2612115Sdyson * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 2712115Sdyson * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2812115Sdyson * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2912115Sdyson * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 3012115Sdyson * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 3112115Sdyson * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3212115Sdyson * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3312115Sdyson * SUCH DAMAGE. 3412115Sdyson * 3512115Sdyson * @(#)fs.h 8.7 (Berkeley) 4/19/94 3668568Sbde * $FreeBSD$ 3712115Sdyson */ 3812115Sdyson 39229549Spfg#ifndef _FS_EXT2FS_FS_H_ 40262724Spfg#define _FS_EXT2FS_FS_H_ 41229549Spfg 4212115Sdyson/* 4312115Sdyson * Each disk drive contains some number of file systems. 4412115Sdyson * A file system consists of a number of cylinder groups. 4512115Sdyson * Each cylinder group has inodes and data. 4612115Sdyson * 4712115Sdyson * A file system is described by its super-block, which in turn 4812115Sdyson * describes the cylinder groups. The super-block is critical 4912115Sdyson * data and is replicated in each cylinder group to protect against 5012115Sdyson * catastrophic loss. This is done at `newfs' time and the critical 5112115Sdyson * super-block data does not change, so the copies need not be 5212115Sdyson * referenced further unless disaster strikes. 5312115Sdyson * 5412115Sdyson * The first boot and super blocks are given in absolute disk addresses. 5512115Sdyson * The byte-offset forms are preferred, as they don't imply a sector size. 5612115Sdyson */ 57262724Spfg#define SBSIZE 1024 58262724Spfg#define SBLOCK 2 5912115Sdyson 6012115Sdyson/* 6112115Sdyson * The path name on which the file system is mounted is maintained 6212115Sdyson * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in 63202283Slulf * the super block for this name. 6412115Sdyson */ 65262724Spfg#define MAXMNTLEN 512 6612115Sdyson 6712115Sdyson/* 68252099Spfg * A summary of contiguous blocks of various sizes is maintained 69252099Spfg * in each cylinder group. Normally this is set by the initial 70252099Spfg * value of fs_maxcontig. 71252099Spfg * 72252099Spfg * XXX:FS_MAXCONTIG is set to 16 to conserve space. Here we set 73252099Spfg * EXT2_MAXCONTIG to 32 for better performance. 74252099Spfg */ 75262724Spfg#define EXT2_MAXCONTIG 32 76252099Spfg 77252099Spfg/* 78202283Slulf * Grigoriy Orlov <gluk@ptci.ru> has done some extensive work to fine 79202283Slulf * tune the layout preferences for directories within a filesystem. 80202283Slulf * His algorithm can be tuned by adjusting the following parameters 81202283Slulf * which tell the system the average file size and the average number 82202283Slulf * of files per directory. These defaults are well selected for typical 83202283Slulf * filesystems, but may need to be tuned for odd cases like filesystems 84202283Slulf * being used for squid caches or news spools. 85202283Slulf * AVFPDIR is the expected number of files per directory. AVGDIRSIZE is 86202283Slulf * obtained by multiplying AVFPDIR and AVFILESIZ which is assumed to be 87202283Slulf * 16384. 8812115Sdyson */ 8912115Sdyson 90262724Spfg#define AFPDIR 64 91262724Spfg#define AVGDIRSIZE 1048576 92202283Slulf 9312115Sdyson/* 94202283Slulf * Macros for access to superblock array structures 9512115Sdyson */ 9612115Sdyson 9712115Sdyson/* 9812115Sdyson * Turn file system block numbers into disk block addresses. 9912115Sdyson * This maps file system blocks to device size blocks. 10012115Sdyson */ 101262724Spfg#define fsbtodb(fs, b) ((daddr_t)(b) << (fs)->e2fs_fsbtodb) 102252234Spfg#define dbtofsb(fs, b) ((b) >> (fs)->e2fs_fsbtodb) 10312115Sdyson 10412115Sdyson/* get group containing inode */ 105262724Spfg#define ino_to_cg(fs, x) (((x) - 1) / (fs->e2fs_ipg)) 10612115Sdyson 10712115Sdyson/* get block containing inode from its number x */ 108262724Spfg#define ino_to_fsba(fs, x) \ 109202283Slulf ((fs)->e2fs_gd[ino_to_cg((fs), (x))].ext2bgd_i_tables + \ 110202283Slulf (((x) - 1) % (fs)->e2fs->e2fs_ipg) / (fs)->e2fs_ipb) 11112115Sdyson 11212115Sdyson/* get offset for inode in block */ 113202283Slulf#define ino_to_fsbo(fs, x) ((x-1) % (fs->e2fs_ipb)) 11412115Sdyson 11512115Sdyson/* 11612115Sdyson * Give cylinder group number for a file system block. 11712115Sdyson * Give cylinder group block number for a file system block. 11812115Sdyson */ 119202283Slulf#define dtog(fs, d) (((d) - fs->e2fs->e2fs_first_dblock) / \ 12012115Sdyson EXT2_BLOCKS_PER_GROUP(fs)) 121202283Slulf#define dtogd(fs, d) (((d) - fs->e2fs->e2fs_first_dblock) % \ 12212115Sdyson EXT2_BLOCKS_PER_GROUP(fs)) 12312115Sdyson 12412115Sdyson/* 12512115Sdyson * The following macros optimize certain frequently calculated 12612115Sdyson * quantities by using shifts and masks in place of divisions 12712115Sdyson * modulos and multiplications. 12812115Sdyson */ 129262724Spfg#define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \ 130202283Slulf ((loc) & (fs)->e2fs_qbmask) 13112115Sdyson 132262724Spfg#define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \ 133202283Slulf ((blk) << (fs->e2fs_bshift)) 13412115Sdyson 135262724Spfg#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \ 136202283Slulf ((loc) >> (fs->e2fs_bshift)) 13712115Sdyson 13812115Sdyson/* no fragments -> logical block number equal # of frags */ 139262724Spfg#define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \ 140202283Slulf ((loc) >> (fs->e2fs_bshift)) 14112115Sdyson 142262724Spfg#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \ 143202283Slulf roundup(size, fs->e2fs_fsize) 14412115Sdyson /* was (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) */ 14512115Sdyson 14612115Sdyson/* 14712115Sdyson * Determining the size of a file block in the file system. 14812115Sdyson * easy w/o fragments 14912115Sdyson */ 150262724Spfg#define blksize(fs, ip, lbn) ((fs)->e2fs_fsize) 15112115Sdyson 15212115Sdyson/* 15312115Sdyson * INOPB is the number of inodes in a secondary storage block. 15412115Sdyson */ 155202283Slulf#define INOPB(fs) (fs->e2fs_ipb) 15612115Sdyson 15712115Sdyson/* 15812115Sdyson * NINDIR is the number of indirects in a file system block. 15912115Sdyson */ 16012115Sdyson#define NINDIR(fs) (EXT2_ADDR_PER_BLOCK(fs)) 16112115Sdyson 162229549Spfg#endif /* !_FS_EXT2FS_FS_H_ */ 163