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 1.6 2004/05/18 00:16:46 cpressey 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 57 /* 58 * Bmap converts a the logical block number of a file to its physical block 59 * number on the disk. The conversion is done by using the logical block 60 * number to index into the array of block pointers described by the dinode. 61 * 62 * ufs_bmap(struct vnode *a_vp, ufs_daddr_t a_bn, struct vnode **a_vpp, 63 * ufs_daddr_t *a_bnp, int *a_runp, int *a_runb) 64 */ 65 int 66 ufs_bmap(struct vop_bmap_args *ap) 67 { 68 /* 69 * Check for underlying vnode requests and ensure that logical 70 * to physical mapping is requested. 71 */ 72 if (ap->a_vpp != NULL) 73 *ap->a_vpp = VTOI(ap->a_vp)->i_devvp; 74 if (ap->a_bnp == NULL) 75 return (0); 76 77 return (ufs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL, 78 ap->a_runp, ap->a_runb)); 79 } 80 81 /* 82 * Indirect blocks are now on the vnode for the file. They are given negative 83 * logical block numbers. Indirect blocks are addressed by the negative 84 * address of the first data block to which they point. Double indirect blocks 85 * are addressed by one less than the address of the first indirect block to 86 * which they point. Triple indirect blocks are addressed by one less than 87 * the address of the first double indirect block to which they point. 88 * 89 * ufs_bmaparray does the bmap conversion, and if requested returns the 90 * array of logical blocks which must be traversed to get to a block. 91 * Each entry contains the offset into that block that gets you to the 92 * next block and the disk address of the block (if it is assigned). 93 */ 94 95 int 96 ufs_bmaparray(struct vnode *vp, ufs_daddr_t bn, ufs_daddr_t *bnp, 97 struct indir *ap, int *nump, int *runp, int *runb) 98 { 99 struct inode *ip; 100 struct buf *bp; 101 struct ufsmount *ump; 102 struct mount *mp; 103 struct vnode *devvp; 104 struct indir a[NIADDR+1], *xap; 105 ufs_daddr_t daddr; 106 long metalbn; 107 int error, maxrun, num; 108 109 ip = VTOI(vp); 110 mp = vp->v_mount; 111 ump = VFSTOUFS(mp); 112 devvp = ump->um_devvp; 113 #ifdef DIAGNOSTIC 114 if ((ap != NULL && nump == NULL) || (ap == NULL && nump != NULL)) 115 panic("ufs_bmaparray: invalid arguments"); 116 #endif 117 118 if (runp) { 119 *runp = 0; 120 } 121 122 if (runb) { 123 *runb = 0; 124 } 125 126 maxrun = mp->mnt_iosize_max / mp->mnt_stat.f_iosize - 1; 127 128 xap = ap == NULL ? a : ap; 129 if (!nump) 130 nump = # 131 error = ufs_getlbns(vp, bn, xap, nump); 132 if (error) 133 return (error); 134 135 num = *nump; 136 if (num == 0) { 137 *bnp = blkptrtodb(ump, ip->i_db[bn]); 138 if (*bnp == 0) 139 *bnp = -1; 140 else if (runp) { 141 daddr_t bnb = bn; 142 for (++bn; bn < NDADDR && *runp < maxrun && 143 is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]); 144 ++bn, ++*runp); 145 bn = bnb; 146 if (runb && (bn > 0)) { 147 for (--bn; (bn >= 0) && (*runb < maxrun) && 148 is_sequential(ump, ip->i_db[bn], 149 ip->i_db[bn+1]); 150 --bn, ++*runb); 151 } 152 } 153 return (0); 154 } 155 156 157 /* Get disk address out of indirect block array */ 158 daddr = ip->i_ib[xap->in_off]; 159 160 for (bp = NULL, ++xap; --num; ++xap) { 161 /* 162 * Exit the loop if there is no disk address assigned yet and 163 * the indirect block isn't in the cache, or if we were 164 * looking for an indirect block and we've found it. 165 */ 166 167 metalbn = xap->in_lbn; 168 if ((daddr == 0 && !incore(vp, metalbn)) || metalbn == bn) 169 break; 170 /* 171 * If we get here, we've either got the block in the cache 172 * or we have a disk address for it, go fetch it. 173 */ 174 if (bp) 175 bqrelse(bp); 176 177 xap->in_exists = 1; 178 bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0); 179 if ((bp->b_flags & B_CACHE) == 0) { 180 #ifdef DIAGNOSTIC 181 if (!daddr) 182 panic("ufs_bmaparray: indirect block not in cache"); 183 #endif 184 bp->b_blkno = blkptrtodb(ump, daddr); 185 bp->b_flags |= B_READ; 186 bp->b_flags &= ~(B_INVAL|B_ERROR); 187 vfs_busy_pages(bp, 0); 188 VOP_STRATEGY(bp->b_vp, bp); 189 error = biowait(bp); 190 if (error) { 191 brelse(bp); 192 return (error); 193 } 194 } 195 196 daddr = ((ufs_daddr_t *)bp->b_data)[xap->in_off]; 197 if (num == 1 && daddr && runp) { 198 for (bn = xap->in_off + 1; 199 bn < MNINDIR(ump) && *runp < maxrun && 200 is_sequential(ump, 201 ((ufs_daddr_t *)bp->b_data)[bn - 1], 202 ((ufs_daddr_t *)bp->b_data)[bn]); 203 ++bn, ++*runp); 204 bn = xap->in_off; 205 if (runb && bn) { 206 for(--bn; bn >= 0 && *runb < maxrun && 207 is_sequential(ump, ((daddr_t *)bp->b_data)[bn], 208 ((daddr_t *)bp->b_data)[bn+1]); 209 --bn, ++*runb); 210 } 211 } 212 } 213 if (bp) 214 bqrelse(bp); 215 216 daddr = blkptrtodb(ump, daddr); 217 *bnp = daddr == 0 ? -1 : daddr; 218 return (0); 219 } 220 221 /* 222 * Create an array of logical block number/offset pairs which represent the 223 * path of indirect blocks required to access a data block. The first "pair" 224 * contains the logical block number of the appropriate single, double or 225 * triple indirect block and the offset into the inode indirect block array. 226 * Note, the logical block number of the inode single/double/triple indirect 227 * block appears twice in the array, once with the offset into the i_ib and 228 * once with the offset into the page itself. 229 */ 230 int 231 ufs_getlbns(struct vnode *vp, ufs_daddr_t bn, struct indir *ap, int *nump) 232 { 233 long blockcnt, metalbn, realbn; 234 struct ufsmount *ump; 235 int i, numlevels, off; 236 int64_t qblockcnt; 237 238 ump = VFSTOUFS(vp->v_mount); 239 if (nump) 240 *nump = 0; 241 numlevels = 0; 242 realbn = bn; 243 if ((long)bn < 0) 244 bn = -(long)bn; 245 246 /* The first NDADDR blocks are direct blocks. */ 247 if (bn < NDADDR) 248 return (0); 249 250 /* 251 * Determine the number of levels of indirection. After this loop 252 * is done, blockcnt indicates the number of data blocks possible 253 * at the previous level of indirection, and NIADDR - i is the number 254 * of levels of indirection needed to locate the requested block. 255 */ 256 for (blockcnt = 1, i = NIADDR, bn -= NDADDR;; i--, bn -= blockcnt) { 257 if (i == 0) 258 return (EFBIG); 259 /* 260 * Use int64_t's here to avoid overflow for triple indirect 261 * blocks when longs have 32 bits and the block size is more 262 * than 4K. 263 */ 264 qblockcnt = (int64_t)blockcnt * MNINDIR(ump); 265 if (bn < qblockcnt) 266 break; 267 blockcnt = qblockcnt; 268 } 269 270 /* Calculate the address of the first meta-block. */ 271 if (realbn >= 0) 272 metalbn = -(realbn - bn + NIADDR - i); 273 else 274 metalbn = -(-realbn - bn + NIADDR - i); 275 276 /* 277 * At each iteration, off is the offset into the bap array which is 278 * an array of disk addresses at the current level of indirection. 279 * The logical block number and the offset in that block are stored 280 * into the argument array. 281 */ 282 ap->in_lbn = metalbn; 283 ap->in_off = off = NIADDR - i; 284 ap->in_exists = 0; 285 ap++; 286 for (++numlevels; i <= NIADDR; i++) { 287 /* If searching for a meta-data block, quit when found. */ 288 if (metalbn == realbn) 289 break; 290 291 off = (bn / blockcnt) % MNINDIR(ump); 292 293 ++numlevels; 294 ap->in_lbn = metalbn; 295 ap->in_off = off; 296 ap->in_exists = 0; 297 ++ap; 298 299 metalbn -= -1 + off * blockcnt; 300 blockcnt /= MNINDIR(ump); 301 } 302 if (nump) 303 *nump = numlevels; 304 return (0); 305 } 306