ext2_subr.c revision 331722
1/*- 2 * modified for 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, 1989, 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 * @(#)ffs_subr.c 8.2 (Berkeley) 9/21/93 36 * $FreeBSD: stable/11/sys/fs/ext2fs/ext2_subr.c 331722 2018-03-29 02:50:57Z eadler $ 37 */ 38 39#include <sys/param.h> 40 41#include <sys/proc.h> 42#include <sys/systm.h> 43#include <sys/bio.h> 44#include <sys/buf.h> 45#include <sys/lock.h> 46#include <sys/ucred.h> 47#include <sys/vnode.h> 48 49#include <fs/ext2fs/inode.h> 50#include <fs/ext2fs/ext2_extern.h> 51#include <fs/ext2fs/ext2fs.h> 52#include <fs/ext2fs/fs.h> 53#include <fs/ext2fs/ext2_extents.h> 54#include <fs/ext2fs/ext2_mount.h> 55#include <fs/ext2fs/ext2_dinode.h> 56 57/* 58 * Return buffer with the contents of block "offset" from the beginning of 59 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 60 * remaining space in the directory. 61 */ 62int 63ext2_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp) 64{ 65 struct inode *ip; 66 struct m_ext2fs *fs; 67 struct buf *bp; 68 e2fs_lbn_t lbn; 69 int bsize, error; 70 daddr_t newblk; 71 struct ext4_extent *ep; 72 struct ext4_extent_path path; 73 74 ip = VTOI(vp); 75 fs = ip->i_e2fs; 76 lbn = lblkno(fs, offset); 77 bsize = blksize(fs, ip, lbn); 78 *bpp = NULL; 79 80 /* 81 * IN_E4EXTENTS requires special treatment as we can otherwise fall 82 * back to the normal path. 83 */ 84 if (!(ip->i_flag & IN_E4EXTENTS)) 85 goto normal; 86 87 memset(&path, 0, sizeof(path)); 88 if (ext4_ext_find_extent(fs, ip, lbn, &path) == NULL) 89 goto normal; 90 ep = path.ep_ext; 91 if (ep == NULL) 92 goto normal; 93 94 newblk = lbn - ep->e_blk + 95 (ep->e_start_lo | (daddr_t)ep->e_start_hi << 32); 96 97 if (path.ep_bp != NULL) { 98 brelse(path.ep_bp); 99 path.ep_bp = NULL; 100 } 101 error = bread(ip->i_devvp, fsbtodb(fs, newblk), bsize, NOCRED, &bp); 102 if (error != 0) { 103 brelse(bp); 104 return (error); 105 } 106 if (res) 107 *res = (char *)bp->b_data + blkoff(fs, offset); 108 /* 109 * If IN_E4EXTENTS is enabled we would get a wrong offset so 110 * reset b_offset here. 111 */ 112 bp->b_offset = lbn * bsize; 113 *bpp = bp; 114 return (0); 115 116normal: 117 if (*bpp == NULL) { 118 if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) { 119 brelse(bp); 120 return (error); 121 } 122 if (res) 123 *res = (char *)bp->b_data + blkoff(fs, offset); 124 *bpp = bp; 125 } 126 return (0); 127} 128 129/* 130 * Update the cluster map because of an allocation of free like ffs. 131 * 132 * Cnt == 1 means free; cnt == -1 means allocating. 133 */ 134void 135ext2_clusteracct(struct m_ext2fs *fs, char *bbp, int cg, daddr_t bno, int cnt) 136{ 137 int32_t *sump = fs->e2fs_clustersum[cg].cs_sum; 138 int32_t *lp; 139 int back, bit, end, forw, i, loc, start; 140 141 /* Initialize the cluster summary array. */ 142 if (fs->e2fs_clustersum[cg].cs_init == 0) { 143 int run = 0; 144 145 bit = 1; 146 loc = 0; 147 148 for (i = 0; i < fs->e2fs->e2fs_fpg; i++) { 149 if ((bbp[loc] & bit) == 0) 150 run++; 151 else if (run != 0) { 152 if (run > fs->e2fs_contigsumsize) 153 run = fs->e2fs_contigsumsize; 154 sump[run]++; 155 run = 0; 156 } 157 if ((i & (NBBY - 1)) != (NBBY - 1)) 158 bit <<= 1; 159 else { 160 loc++; 161 bit = 1; 162 } 163 } 164 if (run != 0) { 165 if (run > fs->e2fs_contigsumsize) 166 run = fs->e2fs_contigsumsize; 167 sump[run]++; 168 } 169 fs->e2fs_clustersum[cg].cs_init = 1; 170 } 171 172 if (fs->e2fs_contigsumsize <= 0) 173 return; 174 175 /* Find the size of the cluster going forward. */ 176 start = bno + 1; 177 end = start + fs->e2fs_contigsumsize; 178 if (end > fs->e2fs->e2fs_fpg) 179 end = fs->e2fs->e2fs_fpg; 180 loc = start / NBBY; 181 bit = 1 << (start % NBBY); 182 for (i = start; i < end; i++) { 183 if ((bbp[loc] & bit) != 0) 184 break; 185 if ((i & (NBBY - 1)) != (NBBY - 1)) 186 bit <<= 1; 187 else { 188 loc++; 189 bit = 1; 190 } 191 } 192 forw = i - start; 193 194 /* Find the size of the cluster going backward. */ 195 start = bno - 1; 196 end = start - fs->e2fs_contigsumsize; 197 if (end < 0) 198 end = -1; 199 loc = start / NBBY; 200 bit = 1 << (start % NBBY); 201 for (i = start; i > end; i--) { 202 if ((bbp[loc] & bit) != 0) 203 break; 204 if ((i & (NBBY - 1)) != 0) 205 bit >>= 1; 206 else { 207 loc--; 208 bit = 1 << (NBBY - 1); 209 } 210 } 211 back = start - i; 212 213 /* 214 * Account for old cluster and the possibly new forward and 215 * back clusters. 216 */ 217 i = back + forw + 1; 218 if (i > fs->e2fs_contigsumsize) 219 i = fs->e2fs_contigsumsize; 220 sump[i] += cnt; 221 if (back > 0) 222 sump[back] -= cnt; 223 if (forw > 0) 224 sump[forw] -= cnt; 225 226 /* Update cluster summary information. */ 227 lp = &sump[fs->e2fs_contigsumsize]; 228 for (i = fs->e2fs_contigsumsize; i > 0; i--) 229 if (*lp-- > 0) 230 break; 231 fs->e2fs_maxcluster[cg] = i; 232} 233