ulfs_bmap.c revision 1.4.2.4
1 1.4.2.2 tls /* $NetBSD: ulfs_bmap.c,v 1.4.2.4 2017/12/03 11:39:22 jdolecek Exp $ */ 2 1.4.2.2 tls /* from NetBSD: ufs_bmap.c,v 1.50 2013/01/22 09:39:18 dholland Exp */ 3 1.4.2.2 tls 4 1.4.2.2 tls /* 5 1.4.2.2 tls * Copyright (c) 1989, 1991, 1993 6 1.4.2.2 tls * The Regents of the University of California. All rights reserved. 7 1.4.2.2 tls * (c) UNIX System Laboratories, Inc. 8 1.4.2.2 tls * All or some portions of this file are derived from material licensed 9 1.4.2.2 tls * to the University of California by American Telephone and Telegraph 10 1.4.2.2 tls * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 1.4.2.2 tls * the permission of UNIX System Laboratories, Inc. 12 1.4.2.2 tls * 13 1.4.2.2 tls * Redistribution and use in source and binary forms, with or without 14 1.4.2.2 tls * modification, are permitted provided that the following conditions 15 1.4.2.2 tls * are met: 16 1.4.2.2 tls * 1. Redistributions of source code must retain the above copyright 17 1.4.2.2 tls * notice, this list of conditions and the following disclaimer. 18 1.4.2.2 tls * 2. Redistributions in binary form must reproduce the above copyright 19 1.4.2.2 tls * notice, this list of conditions and the following disclaimer in the 20 1.4.2.2 tls * documentation and/or other materials provided with the distribution. 21 1.4.2.2 tls * 3. Neither the name of the University nor the names of its contributors 22 1.4.2.2 tls * may be used to endorse or promote products derived from this software 23 1.4.2.2 tls * without specific prior written permission. 24 1.4.2.2 tls * 25 1.4.2.2 tls * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 1.4.2.2 tls * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 1.4.2.2 tls * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 1.4.2.2 tls * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 1.4.2.2 tls * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 1.4.2.2 tls * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 1.4.2.2 tls * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 1.4.2.2 tls * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 1.4.2.2 tls * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 1.4.2.2 tls * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 1.4.2.2 tls * SUCH DAMAGE. 36 1.4.2.2 tls * 37 1.4.2.2 tls * @(#)ufs_bmap.c 8.8 (Berkeley) 8/11/95 38 1.4.2.2 tls */ 39 1.4.2.2 tls 40 1.4.2.2 tls #include <sys/cdefs.h> 41 1.4.2.2 tls __KERNEL_RCSID(0, "$NetBSD: ulfs_bmap.c,v 1.4.2.4 2017/12/03 11:39:22 jdolecek Exp $"); 42 1.4.2.2 tls 43 1.4.2.2 tls #include <sys/param.h> 44 1.4.2.2 tls #include <sys/systm.h> 45 1.4.2.2 tls #include <sys/stat.h> 46 1.4.2.2 tls #include <sys/buf.h> 47 1.4.2.2 tls #include <sys/proc.h> 48 1.4.2.2 tls #include <sys/vnode.h> 49 1.4.2.2 tls #include <sys/mount.h> 50 1.4.2.2 tls #include <sys/resourcevar.h> 51 1.4.2.2 tls #include <sys/trace.h> 52 1.4.2.2 tls 53 1.4.2.2 tls #include <miscfs/specfs/specdev.h> 54 1.4.2.2 tls 55 1.4.2.2 tls #include <ufs/lfs/ulfs_inode.h> 56 1.4.2.2 tls #include <ufs/lfs/ulfsmount.h> 57 1.4.2.2 tls #include <ufs/lfs/ulfs_extern.h> 58 1.4.2.2 tls #include <ufs/lfs/ulfs_bswap.h> 59 1.4.2.2 tls 60 1.4.2.2 tls static bool 61 1.4.2.3 tls ulfs_issequential(const struct lfs *fs, daddr_t daddr0, daddr_t daddr1) 62 1.4.2.2 tls { 63 1.4.2.2 tls 64 1.4.2.2 tls /* for ulfs, blocks in a hole is not 'contiguous'. */ 65 1.4.2.2 tls if (daddr0 == 0) 66 1.4.2.2 tls return false; 67 1.4.2.2 tls 68 1.4.2.3 tls return (daddr0 + fs->um_seqinc == daddr1); 69 1.4.2.2 tls } 70 1.4.2.2 tls 71 1.4.2.2 tls /* 72 1.4.2.4 jdolecek * This is used for block pointers in inodes and elsewhere, which can 73 1.4.2.4 jdolecek * contain the magic value UNWRITTEN, which is -2. This is mishandled 74 1.4.2.4 jdolecek * by u32 -> u64 promotion unless special-cased. 75 1.4.2.4 jdolecek * 76 1.4.2.4 jdolecek * XXX this should be rolled into better inode accessors and go away. 77 1.4.2.4 jdolecek */ 78 1.4.2.4 jdolecek static inline uint64_t 79 1.4.2.4 jdolecek ulfs_fix_unwritten(uint32_t val) 80 1.4.2.4 jdolecek { 81 1.4.2.4 jdolecek if (val == (uint32_t)UNWRITTEN) { 82 1.4.2.4 jdolecek return (uint64_t)(int64_t)UNWRITTEN; 83 1.4.2.4 jdolecek } else { 84 1.4.2.4 jdolecek return val; 85 1.4.2.4 jdolecek } 86 1.4.2.4 jdolecek } 87 1.4.2.4 jdolecek 88 1.4.2.4 jdolecek 89 1.4.2.4 jdolecek /* 90 1.4.2.2 tls * Bmap converts the logical block number of a file to its physical block 91 1.4.2.2 tls * number on the disk. The conversion is done by using the logical block 92 1.4.2.2 tls * number to index into the array of block pointers described by the dinode. 93 1.4.2.2 tls */ 94 1.4.2.2 tls int 95 1.4.2.2 tls ulfs_bmap(void *v) 96 1.4.2.2 tls { 97 1.4.2.2 tls struct vop_bmap_args /* { 98 1.4.2.2 tls struct vnode *a_vp; 99 1.4.2.2 tls daddr_t a_bn; 100 1.4.2.2 tls struct vnode **a_vpp; 101 1.4.2.2 tls daddr_t *a_bnp; 102 1.4.2.2 tls int *a_runp; 103 1.4.2.2 tls } */ *ap = v; 104 1.4.2.2 tls int error; 105 1.4.2.2 tls 106 1.4.2.2 tls /* 107 1.4.2.2 tls * Check for underlying vnode requests and ensure that logical 108 1.4.2.2 tls * to physical mapping is requested. 109 1.4.2.2 tls */ 110 1.4.2.2 tls if (ap->a_vpp != NULL) 111 1.4.2.2 tls *ap->a_vpp = VTOI(ap->a_vp)->i_devvp; 112 1.4.2.2 tls if (ap->a_bnp == NULL) 113 1.4.2.2 tls return (0); 114 1.4.2.2 tls 115 1.4.2.2 tls error = ulfs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL, 116 1.4.2.2 tls ap->a_runp, ulfs_issequential); 117 1.4.2.2 tls return error; 118 1.4.2.2 tls } 119 1.4.2.2 tls 120 1.4.2.2 tls /* 121 1.4.2.2 tls * Indirect blocks are now on the vnode for the file. They are given negative 122 1.4.2.2 tls * logical block numbers. Indirect blocks are addressed by the negative 123 1.4.2.2 tls * address of the first data block to which they point. Double indirect blocks 124 1.4.2.2 tls * are addressed by one less than the address of the first indirect block to 125 1.4.2.2 tls * which they point. Triple indirect blocks are addressed by one less than 126 1.4.2.2 tls * the address of the first double indirect block to which they point. 127 1.4.2.2 tls * 128 1.4.2.2 tls * ulfs_bmaparray does the bmap conversion, and if requested returns the 129 1.4.2.2 tls * array of logical blocks which must be traversed to get to a block. 130 1.4.2.2 tls * Each entry contains the offset into that block that gets you to the 131 1.4.2.2 tls * next block and the disk address of the block (if it is assigned). 132 1.4.2.2 tls */ 133 1.4.2.2 tls 134 1.4.2.2 tls int 135 1.4.2.2 tls ulfs_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *bnp, struct indir *ap, 136 1.4.2.2 tls int *nump, int *runp, ulfs_issequential_callback_t is_sequential) 137 1.4.2.2 tls { 138 1.4.2.2 tls struct inode *ip; 139 1.4.2.2 tls struct buf *bp, *cbp; 140 1.4.2.2 tls struct ulfsmount *ump; 141 1.4.2.3 tls struct lfs *fs; 142 1.4.2.2 tls struct mount *mp; 143 1.4.2.2 tls struct indir a[ULFS_NIADDR + 1], *xap; 144 1.4.2.2 tls daddr_t daddr; 145 1.4.2.2 tls daddr_t metalbn; 146 1.4.2.2 tls int error, maxrun = 0, num; 147 1.4.2.2 tls 148 1.4.2.2 tls ip = VTOI(vp); 149 1.4.2.2 tls mp = vp->v_mount; 150 1.4.2.2 tls ump = ip->i_ump; 151 1.4.2.3 tls fs = ip->i_lfs; 152 1.4.2.4 jdolecek KASSERTMSG(((ap == NULL) == (nump == NULL)), 153 1.4.2.4 jdolecek "ulfs_bmaparray: invalid arguments: ap=%p, nump=%p", ap, nump); 154 1.4.2.2 tls 155 1.4.2.2 tls if (runp) { 156 1.4.2.2 tls /* 157 1.4.2.2 tls * XXX 158 1.4.2.2 tls * If MAXBSIZE is the largest transfer the disks can handle, 159 1.4.2.2 tls * we probably want maxrun to be 1 block less so that we 160 1.4.2.2 tls * don't create a block larger than the device can handle. 161 1.4.2.2 tls */ 162 1.4.2.2 tls *runp = 0; 163 1.4.2.2 tls maxrun = MAXPHYS / mp->mnt_stat.f_iosize - 1; 164 1.4.2.2 tls } 165 1.4.2.2 tls 166 1.4.2.2 tls if (bn >= 0 && bn < ULFS_NDADDR) { 167 1.4.2.2 tls if (nump != NULL) 168 1.4.2.2 tls *nump = 0; 169 1.4.2.2 tls if (ump->um_fstype == ULFS1) 170 1.4.2.4 jdolecek daddr = ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_db[bn], 171 1.4.2.4 jdolecek ULFS_MPNEEDSWAP(fs))); 172 1.4.2.2 tls else 173 1.4.2.4 jdolecek daddr = ulfs_rw64(ip->i_din->u_64.di_db[bn], 174 1.4.2.3 tls ULFS_MPNEEDSWAP(fs)); 175 1.4.2.3 tls *bnp = blkptrtodb(fs, daddr); 176 1.4.2.2 tls /* 177 1.4.2.2 tls * Since this is FFS independent code, we are out of 178 1.4.2.2 tls * scope for the definitions of BLK_NOCOPY and 179 1.4.2.2 tls * BLK_SNAP, but we do know that they will fall in 180 1.4.2.2 tls * the range 1..um_seqinc, so we use that test and 181 1.4.2.2 tls * return a request for a zeroed out buffer if attempts 182 1.4.2.2 tls * are made to read a BLK_NOCOPY or BLK_SNAP block. 183 1.4.2.2 tls */ 184 1.4.2.2 tls if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) == SF_SNAPSHOT 185 1.4.2.2 tls && daddr > 0 && 186 1.4.2.3 tls daddr < fs->um_seqinc) { 187 1.4.2.2 tls *bnp = -1; 188 1.4.2.2 tls } else if (*bnp == 0) { 189 1.4.2.2 tls if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) 190 1.4.2.2 tls == SF_SNAPSHOT) { 191 1.4.2.3 tls *bnp = blkptrtodb(fs, bn * fs->um_seqinc); 192 1.4.2.2 tls } else { 193 1.4.2.2 tls *bnp = -1; 194 1.4.2.2 tls } 195 1.4.2.2 tls } else if (runp) { 196 1.4.2.2 tls if (ump->um_fstype == ULFS1) { 197 1.4.2.2 tls for (++bn; bn < ULFS_NDADDR && *runp < maxrun && 198 1.4.2.3 tls is_sequential(fs, 199 1.4.2.4 jdolecek ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_db[bn - 1], 200 1.4.2.4 jdolecek ULFS_MPNEEDSWAP(fs))), 201 1.4.2.4 jdolecek ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_db[bn], 202 1.4.2.4 jdolecek ULFS_MPNEEDSWAP(fs)))); 203 1.4.2.2 tls ++bn, ++*runp); 204 1.4.2.2 tls } else { 205 1.4.2.2 tls for (++bn; bn < ULFS_NDADDR && *runp < maxrun && 206 1.4.2.3 tls is_sequential(fs, 207 1.4.2.4 jdolecek ulfs_rw64(ip->i_din->u_64.di_db[bn - 1], 208 1.4.2.3 tls ULFS_MPNEEDSWAP(fs)), 209 1.4.2.4 jdolecek ulfs_rw64(ip->i_din->u_64.di_db[bn], 210 1.4.2.3 tls ULFS_MPNEEDSWAP(fs))); 211 1.4.2.2 tls ++bn, ++*runp); 212 1.4.2.2 tls } 213 1.4.2.2 tls } 214 1.4.2.2 tls return (0); 215 1.4.2.2 tls } 216 1.4.2.2 tls 217 1.4.2.2 tls xap = ap == NULL ? a : ap; 218 1.4.2.2 tls if (!nump) 219 1.4.2.2 tls nump = # 220 1.4.2.2 tls if ((error = ulfs_getlbns(vp, bn, xap, nump)) != 0) 221 1.4.2.2 tls return (error); 222 1.4.2.2 tls 223 1.4.2.2 tls num = *nump; 224 1.4.2.2 tls 225 1.4.2.2 tls /* Get disk address out of indirect block array */ 226 1.4.2.4 jdolecek // XXX clean this up 227 1.4.2.2 tls if (ump->um_fstype == ULFS1) 228 1.4.2.4 jdolecek daddr = ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_ib[xap->in_off], 229 1.4.2.4 jdolecek ULFS_MPNEEDSWAP(fs))); 230 1.4.2.2 tls else 231 1.4.2.4 jdolecek daddr = ulfs_rw64(ip->i_din->u_64.di_ib[xap->in_off], 232 1.4.2.3 tls ULFS_MPNEEDSWAP(fs)); 233 1.4.2.2 tls 234 1.4.2.2 tls for (bp = NULL, ++xap; --num; ++xap) { 235 1.4.2.2 tls /* 236 1.4.2.2 tls * Exit the loop if there is no disk address assigned yet and 237 1.4.2.2 tls * the indirect block isn't in the cache, or if we were 238 1.4.2.2 tls * looking for an indirect block and we've found it. 239 1.4.2.2 tls */ 240 1.4.2.2 tls 241 1.4.2.2 tls metalbn = xap->in_lbn; 242 1.4.2.2 tls if (metalbn == bn) 243 1.4.2.2 tls break; 244 1.4.2.2 tls if (daddr == 0) { 245 1.4.2.2 tls mutex_enter(&bufcache_lock); 246 1.4.2.2 tls cbp = incore(vp, metalbn); 247 1.4.2.2 tls mutex_exit(&bufcache_lock); 248 1.4.2.2 tls if (cbp == NULL) 249 1.4.2.2 tls break; 250 1.4.2.2 tls } 251 1.4.2.2 tls 252 1.4.2.2 tls /* 253 1.4.2.2 tls * If we get here, we've either got the block in the cache 254 1.4.2.2 tls * or we have a disk address for it, go fetch it. 255 1.4.2.2 tls */ 256 1.4.2.2 tls if (bp) 257 1.4.2.2 tls brelse(bp, 0); 258 1.4.2.2 tls 259 1.4.2.2 tls xap->in_exists = 1; 260 1.4.2.2 tls bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0); 261 1.4.2.2 tls if (bp == NULL) { 262 1.4.2.2 tls 263 1.4.2.2 tls /* 264 1.4.2.2 tls * getblk() above returns NULL only iff we are 265 1.4.2.2 tls * pagedaemon. See the implementation of getblk 266 1.4.2.2 tls * for detail. 267 1.4.2.2 tls */ 268 1.4.2.2 tls 269 1.4.2.2 tls return (ENOMEM); 270 1.4.2.2 tls } 271 1.4.2.2 tls if (bp->b_oflags & (BO_DONE | BO_DELWRI)) { 272 1.4.2.2 tls trace(TR_BREADHIT, pack(vp, size), metalbn); 273 1.4.2.4 jdolecek } else { 274 1.4.2.4 jdolecek KASSERTMSG(daddr, 275 1.4.2.4 jdolecek "ulfs_bmaparray: indirect block not in cache"); 276 1.4.2.2 tls trace(TR_BREADMISS, pack(vp, size), metalbn); 277 1.4.2.3 tls bp->b_blkno = blkptrtodb(fs, daddr); 278 1.4.2.2 tls bp->b_flags |= B_READ; 279 1.4.2.2 tls BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 280 1.4.2.2 tls VOP_STRATEGY(vp, bp); 281 1.4.2.2 tls curlwp->l_ru.ru_inblock++; /* XXX */ 282 1.4.2.2 tls if ((error = biowait(bp)) != 0) { 283 1.4.2.2 tls brelse(bp, 0); 284 1.4.2.2 tls return (error); 285 1.4.2.2 tls } 286 1.4.2.2 tls } 287 1.4.2.2 tls if (ump->um_fstype == ULFS1) { 288 1.4.2.4 jdolecek daddr = ulfs_fix_unwritten(ulfs_rw32(((u_int32_t *)bp->b_data)[xap->in_off], 289 1.4.2.4 jdolecek ULFS_MPNEEDSWAP(fs))); 290 1.4.2.2 tls if (num == 1 && daddr && runp) { 291 1.4.2.2 tls for (bn = xap->in_off + 1; 292 1.4.2.3 tls bn < MNINDIR(fs) && *runp < maxrun && 293 1.4.2.3 tls is_sequential(fs, 294 1.4.2.4 jdolecek ulfs_fix_unwritten(ulfs_rw32(((int32_t *)bp->b_data)[bn-1], 295 1.4.2.4 jdolecek ULFS_MPNEEDSWAP(fs))), 296 1.4.2.4 jdolecek ulfs_fix_unwritten(ulfs_rw32(((int32_t *)bp->b_data)[bn], 297 1.4.2.4 jdolecek ULFS_MPNEEDSWAP(fs)))); 298 1.4.2.2 tls ++bn, ++*runp); 299 1.4.2.2 tls } 300 1.4.2.2 tls } else { 301 1.4.2.2 tls daddr = ulfs_rw64(((u_int64_t *)bp->b_data)[xap->in_off], 302 1.4.2.3 tls ULFS_MPNEEDSWAP(fs)); 303 1.4.2.2 tls if (num == 1 && daddr && runp) { 304 1.4.2.2 tls for (bn = xap->in_off + 1; 305 1.4.2.3 tls bn < MNINDIR(fs) && *runp < maxrun && 306 1.4.2.3 tls is_sequential(fs, 307 1.4.2.2 tls ulfs_rw64(((int64_t *)bp->b_data)[bn-1], 308 1.4.2.3 tls ULFS_MPNEEDSWAP(fs)), 309 1.4.2.2 tls ulfs_rw64(((int64_t *)bp->b_data)[bn], 310 1.4.2.3 tls ULFS_MPNEEDSWAP(fs))); 311 1.4.2.2 tls ++bn, ++*runp); 312 1.4.2.2 tls } 313 1.4.2.2 tls } 314 1.4.2.2 tls } 315 1.4.2.2 tls if (bp) 316 1.4.2.2 tls brelse(bp, 0); 317 1.4.2.2 tls 318 1.4.2.2 tls /* 319 1.4.2.2 tls * Since this is FFS independent code, we are out of scope for the 320 1.4.2.2 tls * definitions of BLK_NOCOPY and BLK_SNAP, but we do know that they 321 1.4.2.2 tls * will fall in the range 1..um_seqinc, so we use that test and 322 1.4.2.2 tls * return a request for a zeroed out buffer if attempts are made 323 1.4.2.2 tls * to read a BLK_NOCOPY or BLK_SNAP block. 324 1.4.2.2 tls */ 325 1.4.2.2 tls if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) == SF_SNAPSHOT 326 1.4.2.3 tls && daddr > 0 && daddr < fs->um_seqinc) { 327 1.4.2.2 tls *bnp = -1; 328 1.4.2.2 tls return (0); 329 1.4.2.2 tls } 330 1.4.2.3 tls *bnp = blkptrtodb(fs, daddr); 331 1.4.2.2 tls if (*bnp == 0) { 332 1.4.2.2 tls if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) 333 1.4.2.2 tls == SF_SNAPSHOT) { 334 1.4.2.3 tls *bnp = blkptrtodb(fs, bn * fs->um_seqinc); 335 1.4.2.2 tls } else { 336 1.4.2.2 tls *bnp = -1; 337 1.4.2.2 tls } 338 1.4.2.2 tls } 339 1.4.2.2 tls return (0); 340 1.4.2.2 tls } 341 1.4.2.2 tls 342 1.4.2.2 tls /* 343 1.4.2.2 tls * Create an array of logical block number/offset pairs which represent the 344 1.4.2.2 tls * path of indirect blocks required to access a data block. The first "pair" 345 1.4.2.2 tls * contains the logical block number of the appropriate single, double or 346 1.4.2.2 tls * triple indirect block and the offset into the inode indirect block array. 347 1.4.2.2 tls * Note, the logical block number of the inode single/double/triple indirect 348 1.4.2.2 tls * block appears twice in the array, once with the offset into the i_ffs1_ib and 349 1.4.2.2 tls * once with the offset into the page itself. 350 1.4.2.2 tls */ 351 1.4.2.2 tls int 352 1.4.2.2 tls ulfs_getlbns(struct vnode *vp, daddr_t bn, struct indir *ap, int *nump) 353 1.4.2.2 tls { 354 1.4.2.2 tls daddr_t metalbn, realbn; 355 1.4.2.2 tls struct ulfsmount *ump; 356 1.4.2.3 tls struct lfs *fs; 357 1.4.2.2 tls int64_t blockcnt; 358 1.4.2.2 tls int lbc; 359 1.4.2.2 tls int i, numlevels, off; 360 1.4.2.2 tls 361 1.4.2.2 tls ump = VFSTOULFS(vp->v_mount); 362 1.4.2.3 tls fs = ump->um_lfs; 363 1.4.2.2 tls if (nump) 364 1.4.2.2 tls *nump = 0; 365 1.4.2.2 tls numlevels = 0; 366 1.4.2.2 tls realbn = bn; 367 1.4.2.2 tls if (bn < 0) 368 1.4.2.2 tls bn = -bn; 369 1.4.2.2 tls KASSERT(bn >= ULFS_NDADDR); 370 1.4.2.2 tls 371 1.4.2.2 tls /* 372 1.4.2.2 tls * Determine the number of levels of indirection. After this loop 373 1.4.2.2 tls * is done, blockcnt indicates the number of data blocks possible 374 1.4.2.2 tls * at the given level of indirection, and ULFS_NIADDR - i is the number 375 1.4.2.2 tls * of levels of indirection needed to locate the requested block. 376 1.4.2.2 tls */ 377 1.4.2.2 tls 378 1.4.2.2 tls bn -= ULFS_NDADDR; 379 1.4.2.2 tls for (lbc = 0, i = ULFS_NIADDR;; i--, bn -= blockcnt) { 380 1.4.2.2 tls if (i == 0) 381 1.4.2.2 tls return (EFBIG); 382 1.4.2.2 tls 383 1.4.2.3 tls lbc += fs->um_lognindir; 384 1.4.2.2 tls blockcnt = (int64_t)1 << lbc; 385 1.4.2.2 tls 386 1.4.2.2 tls if (bn < blockcnt) 387 1.4.2.2 tls break; 388 1.4.2.2 tls } 389 1.4.2.2 tls 390 1.4.2.2 tls /* Calculate the address of the first meta-block. */ 391 1.4.2.2 tls metalbn = -((realbn >= 0 ? realbn : -realbn) - bn + ULFS_NIADDR - i); 392 1.4.2.2 tls 393 1.4.2.2 tls /* 394 1.4.2.2 tls * At each iteration, off is the offset into the bap array which is 395 1.4.2.2 tls * an array of disk addresses at the current level of indirection. 396 1.4.2.2 tls * The logical block number and the offset in that block are stored 397 1.4.2.2 tls * into the argument array. 398 1.4.2.2 tls */ 399 1.4.2.2 tls ap->in_lbn = metalbn; 400 1.4.2.2 tls ap->in_off = off = ULFS_NIADDR - i; 401 1.4.2.2 tls ap->in_exists = 0; 402 1.4.2.2 tls ap++; 403 1.4.2.2 tls for (++numlevels; i <= ULFS_NIADDR; i++) { 404 1.4.2.2 tls /* If searching for a meta-data block, quit when found. */ 405 1.4.2.2 tls if (metalbn == realbn) 406 1.4.2.2 tls break; 407 1.4.2.2 tls 408 1.4.2.3 tls lbc -= fs->um_lognindir; 409 1.4.2.3 tls off = (bn >> lbc) & (MNINDIR(fs) - 1); 410 1.4.2.2 tls 411 1.4.2.2 tls ++numlevels; 412 1.4.2.2 tls ap->in_lbn = metalbn; 413 1.4.2.2 tls ap->in_off = off; 414 1.4.2.2 tls ap->in_exists = 0; 415 1.4.2.2 tls ++ap; 416 1.4.2.2 tls 417 1.4.2.2 tls metalbn -= -1 + ((int64_t)off << lbc); 418 1.4.2.2 tls } 419 1.4.2.2 tls if (nump) 420 1.4.2.2 tls *nump = numlevels; 421 1.4.2.2 tls return (0); 422 1.4.2.2 tls } 423
Indexes created Wed Oct 29 18:09:52 GMT 2025