fs.h revision 27881
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 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#)fs.h 8.7 (Berkeley) 4/19/94 40 */ 41 42/* 43 * Each disk drive contains some number of file systems. 44 * A file system consists of a number of cylinder groups. 45 * Each cylinder group has inodes and data. 46 * 47 * A file system is described by its super-block, which in turn 48 * describes the cylinder groups. The super-block is critical 49 * data and is replicated in each cylinder group to protect against 50 * catastrophic loss. This is done at `newfs' time and the critical 51 * super-block data does not change, so the copies need not be 52 * referenced further unless disaster strikes. 53 * 54 * The first boot and super blocks are given in absolute disk addresses. 55 * The byte-offset forms are preferred, as they don't imply a sector size. 56 */ 57#define BBSIZE 1024 58#define SBSIZE 1024 59#define BBOFF ((off_t)(0)) 60#define SBOFF ((off_t)(BBOFF + BBSIZE)) 61#define BBLOCK ((daddr_t)(0)) 62#define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE)) 63 64/* 65 * The path name on which the file system is mounted is maintained 66 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in 67 * the super block for this name. 68 */ 69#define MAXMNTLEN 512 70 71/* 72 * Macros for access to superblock array structures 73 */ 74 75/* 76 * Convert cylinder group to base address of its global summary info. 77 */ 78#define fs_cs(fs, cgindx) (((struct ext2_group_desc *) \ 79 (fs->s_group_desc[cgindx / EXT2_DESC_PER_BLOCK(fs)]->b_data)) \ 80 [cgindx % EXT2_DESC_PER_BLOCK(fs)]) 81 82/* 83 * Turn file system block numbers into disk block addresses. 84 * This maps file system blocks to device size blocks. 85 */ 86#define fsbtodb(fs, b) ((b) << ((fs)->s_fsbtodb)) 87#define dbtofsb(fs, b) ((b) >> ((fs)->s_fsbtodb)) 88 89/* get group containing inode */ 90#define ino_to_cg(fs, x) (((x) - 1) / EXT2_INODES_PER_GROUP(fs)) 91 92/* get block containing inode from its number x */ 93#define ino_to_fsba(fs, x) fs_cs(fs, ino_to_cg(fs, x)).bg_inode_table + \ 94 (((x)-1) % EXT2_INODES_PER_GROUP(fs))/EXT2_INODES_PER_BLOCK(fs) 95 96/* get offset for inode in block */ 97#define ino_to_fsbo(fs, x) ((x-1) % EXT2_INODES_PER_BLOCK(fs)) 98 99/* 100 * Give cylinder group number for a file system block. 101 * Give cylinder group block number for a file system block. 102 */ 103#define dtog(fs, d) (((d) - fs->s_es->s_first_data_block) / \ 104 EXT2_BLOCKS_PER_GROUP(fs)) 105#define dtogd(fs, d) (((d) - fs->s_es->s_first_data_block) % \ 106 EXT2_BLOCKS_PER_GROUP(fs)) 107 108/* 109 * The following macros optimize certain frequently calculated 110 * quantities by using shifts and masks in place of divisions 111 * modulos and multiplications. 112 */ 113#define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \ 114 ((loc) & (fs)->s_qbmask) 115 116#define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \ 117 ((blk) << (fs->s_bshift)) 118 119#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \ 120 ((loc) >> (fs->s_bshift)) 121 122/* no fragments -> logical block number equal # of frags */ 123#define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \ 124 ((loc) >> (fs->s_bshift)) 125 126#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \ 127 roundup(size, fs->s_frag_size) 128 /* was (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) */ 129 130/* 131 * Determining the size of a file block in the file system. 132 * easy w/o fragments 133 */ 134#define blksize(fs, ip, lbn) ((fs)->s_frag_size) 135 136/* 137 * INOPB is the number of inodes in a secondary storage block. 138 */ 139#define INOPB(fs) EXT2_INODES_PER_BLOCK(fs) 140 141/* 142 * NINDIR is the number of indirects in a file system block. 143 */ 144#define NINDIR(fs) (EXT2_ADDR_PER_BLOCK(fs)) 145 146extern int inside[], around[]; 147extern u_char *fragtbl[]; 148 149/* a few remarks about superblock locking/unlocking 150 * Linux provides special routines for doing so 151 * I haven't figured out yet what BSD does 152 * I think I'll try a VOP_LOCK/VOP_UNLOCK on the device vnode 153 */ 154#define DEVVP(inode) (VFSTOUFS(ITOV(inode)->v_mount)->um_devvp) 155#define lock_super(devvp) vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, curproc) 156#define unlock_super(devvp) VOP_UNLOCK(devvp, 0, curproc) 157 158/* 159 * To lock a buffer, set the B_LOCKED flag and then brelse() it. To unlock, 160 * reset the B_LOCKED flag and brelse() the buffer back on the LRU list 161 */ 162#define LCK_BUF(bp) { \ 163 int s; \ 164 s = splbio(); \ 165 (bp)->b_flags |= B_LOCKED; \ 166 splx(s); \ 167 brelse(bp); \ 168} 169 170#define ULCK_BUF(bp) { \ 171 int s; \ 172 s = splbio(); \ 173 (bp)->b_flags &= ~B_LOCKED; \ 174 splx(s); \ 175 bremfree(bp); \ 176 brelse(bp); \ 177} 178