1 /* 2 * Copyright (c) 1989, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)ufs_bmap.c 8.7 (Berkeley) 3/21/95 39 * $FreeBSD: src/sys/ufs/ufs/ufs_bmap.c,v 1.34.2.1 2000/03/17 10:12:14 ps Exp $ 40 * $DragonFly: src/sys/vfs/ufs/ufs_bmap.c,v 1.13 2007/08/13 17:31:57 dillon Exp $ 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/buf.h> 46 #include <sys/proc.h> 47 #include <sys/vnode.h> 48 #include <sys/mount.h> 49 #include <sys/resourcevar.h> 50 #include <sys/conf.h> 51 52 #include "quota.h" 53 #include "inode.h" 54 #include "ufsmount.h" 55 #include "ufs_extern.h" 56 #include "fs.h" 57 58 /* 59 * Bmap converts the logical block number of a file to its physical block 60 * number on the disk. The conversion is done by using the logical block 61 * number to index into the array of block pointers described by the dinode. 62 * 63 * BMAP must return the contiguous before and after run in bytes, inclusive 64 * of the returned block. 65 * 66 * ufs_bmap(struct vnode *a_vp, off_t a_loffset, 67 * off_t *a_doffsetp, int *a_runp, int *a_runb) 68 */ 69 int 70 ufs_bmap(struct vop_bmap_args *ap) 71 { 72 struct fs *fs; 73 ufs_daddr_t lbn; 74 ufs_daddr_t dbn; 75 int error; 76 77 /* 78 * Check for underlying vnode requests and ensure that logical 79 * to physical mapping is requested. 80 */ 81 if (ap->a_doffsetp == NULL) 82 return (0); 83 84 fs = VTOI(ap->a_vp)->i_fs; 85 KKASSERT(((int)ap->a_loffset & ((1 << fs->fs_bshift) - 1)) == 0); 86 lbn = ap->a_loffset >> fs->fs_bshift; 87 88 error = ufs_bmaparray(ap->a_vp, lbn, &dbn, NULL, NULL, 89 ap->a_runp, ap->a_runb); 90 91 if (error || dbn == (ufs_daddr_t)-1) { 92 *ap->a_doffsetp = NOOFFSET; 93 } else { 94 *ap->a_doffsetp = dbtodoff(fs, dbn); 95 if (ap->a_runp) 96 *ap->a_runp = (*ap->a_runp + 1) << fs->fs_bshift; 97 if (ap->a_runb) 98 *ap->a_runb = *ap->a_runb << fs->fs_bshift; 99 } 100 return (error); 101 } 102 103 /* 104 * Indirect blocks are now on the vnode for the file. They are given negative 105 * logical block numbers. Indirect blocks are addressed by the negative 106 * address of the first data block to which they point. Double indirect blocks 107 * are addressed by one less than the address of the first indirect block to 108 * which they point. Triple indirect blocks are addressed by one less than 109 * the address of the first double indirect block to which they point. 110 * 111 * ufs_bmaparray does the bmap conversion, and if requested returns the 112 * array of logical blocks which must be traversed to get to a block. 113 * Each entry contains the offset into that block that gets you to the 114 * next block and the disk address of the block (if it is assigned). 115 */ 116 int 117 ufs_bmaparray(struct vnode *vp, ufs_daddr_t bn, ufs_daddr_t *bnp, 118 struct indir *ap, int *nump, int *runp, int *runb) 119 { 120 struct inode *ip; 121 struct buf *bp; 122 struct ufsmount *ump; 123 struct mount *mp; 124 struct vnode *devvp; 125 struct fs *fs; 126 struct indir a[NIADDR+1], *xap; 127 ufs_daddr_t daddr; 128 long metalbn; 129 int error, maxrun, num; 130 131 ip = VTOI(vp); 132 mp = vp->v_mount; 133 ump = VFSTOUFS(mp); 134 devvp = ump->um_devvp; 135 fs = ip->i_fs; 136 #ifdef DIAGNOSTIC 137 if ((ap != NULL && nump == NULL) || (ap == NULL && nump != NULL)) 138 panic("ufs_bmaparray: invalid arguments"); 139 #endif 140 141 if (runp) { 142 *runp = 0; 143 } 144 145 if (runb) { 146 *runb = 0; 147 } 148 149 maxrun = mp->mnt_iosize_max / mp->mnt_stat.f_iosize - 1; 150 151 xap = ap == NULL ? a : ap; 152 if (!nump) 153 nump = # 154 error = ufs_getlbns(vp, bn, xap, nump); 155 if (error) 156 return (error); 157 158 num = *nump; 159 if (num == 0) { 160 *bnp = blkptrtodb(ump, ip->i_db[bn]); 161 if (*bnp == 0) 162 *bnp = -1; 163 else if (runp) { 164 daddr_t bnb = bn; 165 for (++bn; bn < NDADDR && *runp < maxrun && 166 is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]); 167 ++bn, ++*runp); 168 bn = bnb; 169 if (runb && (bn > 0)) { 170 for (--bn; (bn >= 0) && (*runb < maxrun) && 171 is_sequential(ump, ip->i_db[bn], 172 ip->i_db[bn+1]); 173 --bn, ++*runb); 174 } 175 } 176 return (0); 177 } 178 179 180 /* Get disk address out of indirect block array */ 181 daddr = ip->i_ib[xap->in_off]; 182 183 for (bp = NULL, ++xap; --num; ++xap) { 184 /* 185 * Exit the loop if there is no disk address assigned yet and 186 * the indirect block isn't in the cache, or if we were 187 * looking for an indirect block and we've found it. 188 */ 189 190 metalbn = xap->in_lbn; 191 if ((daddr == 0 && !findblk(vp, dbtodoff(fs, metalbn))) || metalbn == bn) 192 break; 193 /* 194 * If we get here, we've either got the block in the cache 195 * or we have a disk address for it, go fetch it. 196 */ 197 if (bp) 198 bqrelse(bp); 199 200 xap->in_exists = 1; 201 bp = getblk(vp, lblktodoff(fs, metalbn), 202 mp->mnt_stat.f_iosize, 0, 0); 203 if ((bp->b_flags & B_CACHE) == 0) { 204 #ifdef DIAGNOSTIC 205 if (!daddr) 206 panic("ufs_bmaparray: indirect block not in cache"); 207 #endif 208 bp->b_bio2.bio_offset = fsbtodoff(fs, daddr); 209 bp->b_flags &= ~(B_INVAL|B_ERROR); 210 bp->b_cmd = BUF_CMD_READ; 211 vfs_busy_pages(bp->b_vp, bp); 212 vn_strategy(bp->b_vp, &bp->b_bio1); 213 error = biowait(bp); 214 if (error) { 215 brelse(bp); 216 return (error); 217 } 218 } 219 220 daddr = ((ufs_daddr_t *)bp->b_data)[xap->in_off]; 221 if (num == 1 && daddr && runp) { 222 for (bn = xap->in_off + 1; 223 bn < MNINDIR(ump) && *runp < maxrun && 224 is_sequential(ump, 225 ((ufs_daddr_t *)bp->b_data)[bn - 1], 226 ((ufs_daddr_t *)bp->b_data)[bn]); 227 ++bn, ++*runp); 228 bn = xap->in_off; 229 if (runb && bn) { 230 for(--bn; bn >= 0 && *runb < maxrun && 231 is_sequential(ump, ((daddr_t *)bp->b_data)[bn], 232 ((daddr_t *)bp->b_data)[bn+1]); 233 --bn, ++*runb); 234 } 235 } 236 } 237 if (bp) 238 bqrelse(bp); 239 240 daddr = blkptrtodb(ump, daddr); 241 *bnp = daddr == 0 ? -1 : daddr; 242 return (0); 243 } 244 245 /* 246 * Create an array of logical block number/offset pairs which represent the 247 * path of indirect blocks required to access a data block. The first "pair" 248 * contains the logical block number of the appropriate single, double or 249 * triple indirect block and the offset into the inode indirect block array. 250 * Note, the logical block number of the inode single/double/triple indirect 251 * block appears twice in the array, once with the offset into the i_ib and 252 * once with the offset into the page itself. 253 */ 254 int 255 ufs_getlbns(struct vnode *vp, ufs_daddr_t bn, struct indir *ap, int *nump) 256 { 257 long blockcnt, metalbn, realbn; 258 struct ufsmount *ump; 259 int i, numlevels, off; 260 int64_t qblockcnt; 261 262 ump = VFSTOUFS(vp->v_mount); 263 if (nump) 264 *nump = 0; 265 numlevels = 0; 266 realbn = bn; 267 if ((long)bn < 0) 268 bn = -(long)bn; 269 270 /* The first NDADDR blocks are direct blocks. */ 271 if (bn < NDADDR) 272 return (0); 273 274 /* 275 * Determine the number of levels of indirection. After this loop 276 * is done, blockcnt indicates the number of data blocks possible 277 * at the previous level of indirection, and NIADDR - i is the number 278 * of levels of indirection needed to locate the requested block. 279 */ 280 for (blockcnt = 1, i = NIADDR, bn -= NDADDR;; i--, bn -= blockcnt) { 281 if (i == 0) 282 return (EFBIG); 283 /* 284 * Use int64_t's here to avoid overflow for triple indirect 285 * blocks when longs have 32 bits and the block size is more 286 * than 4K. 287 */ 288 qblockcnt = (int64_t)blockcnt * MNINDIR(ump); 289 if (bn < qblockcnt) 290 break; 291 blockcnt = qblockcnt; 292 } 293 294 /* Calculate the address of the first meta-block. */ 295 if (realbn >= 0) 296 metalbn = -(realbn - bn + NIADDR - i); 297 else 298 metalbn = -(-realbn - bn + NIADDR - i); 299 300 /* 301 * At each iteration, off is the offset into the bap array which is 302 * an array of disk addresses at the current level of indirection. 303 * The logical block number and the offset in that block are stored 304 * into the argument array. 305 */ 306 ap->in_lbn = metalbn; 307 ap->in_off = off = NIADDR - i; 308 ap->in_exists = 0; 309 ap++; 310 for (++numlevels; i <= NIADDR; i++) { 311 /* If searching for a meta-data block, quit when found. */ 312 if (metalbn == realbn) 313 break; 314 315 off = (bn / blockcnt) % MNINDIR(ump); 316 317 ++numlevels; 318 ap->in_lbn = metalbn; 319 ap->in_off = off; 320 ap->in_exists = 0; 321 ++ap; 322 323 metalbn -= -1 + off * blockcnt; 324 blockcnt /= MNINDIR(ump); 325 } 326 if (nump) 327 *nump = numlevels; 328 return (0); 329 } 330