/*- * modified for EXT2FS support in Lites 1.1 * * Aug 1995, Godmar Back (gback@cs.utah.edu) * University of Utah, Department of Computer Science */ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1982, 1986, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef _FS_EXT2FS_FS_H_ #define _FS_EXT2FS_FS_H_ /* * Each disk drive contains some number of file systems. * A file system consists of a number of cylinder groups. * Each cylinder group has inodes and data. * * A file system is described by its super-block, which in turn * describes the cylinder groups. The super-block is critical * data and is replicated in each cylinder group to protect against * catastrophic loss. This is done at `newfs' time and the critical * super-block data does not change, so the copies need not be * referenced further unless disaster strikes. * * The first boot and super blocks are given in absolute disk addresses. * The byte-offset forms are preferred, as they don't imply a sector size. */ #define SBLOCK 0 #define SBLOCKSIZE 1024 #define SBLOCKOFFSET 1024 #define SBLOCKBLKSIZE 4096 /* * The path name on which the file system is mounted is maintained * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in * the super block for this name. */ #define MAXMNTLEN 512 /* * A summary of contiguous blocks of various sizes is maintained * in each cylinder group. Normally this is set by the initial * value of fs_maxcontig. * * XXX:FS_MAXCONTIG is set to 16 to conserve space. Here we set * EXT2_MAXCONTIG to 32 for better performance. */ #define EXT2_MAXCONTIG 32 /* * Grigoriy Orlov <gluk@ptci.ru> has done some extensive work to fine * tune the layout preferences for directories within a filesystem. * His algorithm can be tuned by adjusting the following parameters * which tell the system the average file size and the average number * of files per directory. These defaults are well selected for typical * filesystems, but may need to be tuned for odd cases like filesystems * being used for squid caches or news spools. * AVFPDIR is the expected number of files per directory. AVGDIRSIZE is * obtained by multiplying AVFPDIR and AVFILESIZ which is assumed to be * 16384. */ #define AFPDIR 64 #define AVGDIRSIZE 1048576 /* * Macros for access to superblock array structures */ /* * Turn file system block numbers into disk block addresses. * This maps file system blocks to device size blocks. */ #define fsbtodb(fs, b) ((daddr_t)(b) << (fs)->e2fs_fsbtodb) #define dbtofsb(fs, b) ((b) >> (fs)->e2fs_fsbtodb) /* get group containing inode */ #define ino_to_cg(fs, x) (((x) - 1) / (fs->e2fs_ipg)) /* get block containing inode from its number x */ #define ino_to_fsba(fs, x) \ (e2fs_gd_get_i_tables(&(fs)->e2fs_gd[ino_to_cg((fs), (x))]) + \ (((x) - 1) % (fs)->e2fs_ipg) / (fs)->e2fs_ipb) /* get offset for inode in block */ #define ino_to_fsbo(fs, x) ((x-1) % (fs->e2fs_ipb)) /* * Give cylinder group number for a file system block. * Give cylinder group block number for a file system block. */ #define dtog(fs, d) (((d) - le32toh(fs->e2fs->e2fs_first_dblock)) / \ EXT2_BLOCKS_PER_GROUP(fs)) #define dtogd(fs, d) (((d) - le32toh(fs->e2fs->e2fs_first_dblock)) % \ EXT2_BLOCKS_PER_GROUP(fs)) /* * The following macros optimize certain frequently calculated * quantities by using shifts and masks in place of divisions * modulos and multiplications. */ #define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \ ((loc) & (fs)->e2fs_qbmask) #define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \ ((blk) << (fs->e2fs_bshift)) #define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \ ((loc) >> (fs->e2fs_bshift)) /* no fragments -> logical block number equal # of frags */ #define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \ ((loc) >> (fs->e2fs_bshift)) #define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \ roundup(size, fs->e2fs_fsize) /* was (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) */ /* * Determining the size of a file block in the file system. * easy w/o fragments */ #define blksize(fs, ip, lbn) ((fs)->e2fs_fsize) /* * INOPB is the number of inodes in a secondary storage block. */ #define INOPB(fs) (fs->e2fs_ipb) /* * NINDIR is the number of indirects in a file system block. */ #define NINDIR(fs) (EXT2_ADDR_PER_BLOCK(fs)) /* * Use if additional debug logging is required. */ /* #define EXT2FS_PRINT_EXTENTS */ #endif /* !_FS_EXT2FS_FS_H_ */
