1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)ufs_bmap.c 8.7 (Berkeley) 3/21/95 37 * $FreeBSD$ 38 */ 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/bio.h> 43 #include <sys/buf.h> 44 #include <sys/endian.h> 45 #include <sys/proc.h> 46 #include <sys/vnode.h> 47 #include <sys/mount.h> 48 #include <sys/racct.h> 49 #include <sys/resourcevar.h> 50 #include <sys/stat.h> 51 52 #include <fs/ext2fs/fs.h> 53 #include <fs/ext2fs/inode.h> 54 #include <fs/ext2fs/ext2fs.h> 55 #include <fs/ext2fs/ext2_dinode.h> 56 #include <fs/ext2fs/ext2_extern.h> 57 #include <fs/ext2fs/ext2_mount.h> 58 59 /* 60 * Bmap converts the logical block number of a file to its physical block 61 * number on the disk. The conversion is done by using the logical block 62 * number to index into the array of block pointers described by the dinode. 63 */ 64 int 65 ext2_bmap(struct vop_bmap_args *ap) 66 { 67 daddr_t blkno; 68 int error; 69 70 /* 71 * Check for underlying vnode requests and ensure that logical 72 * to physical mapping is requested. 73 */ 74 if (ap->a_bop != NULL) 75 *ap->a_bop = &VTOI(ap->a_vp)->i_devvp->v_bufobj; 76 if (ap->a_bnp == NULL) 77 return (0); 78 79 if (VTOI(ap->a_vp)->i_flag & IN_E4EXTENTS) 80 error = ext4_bmapext(ap->a_vp, ap->a_bn, &blkno, 81 ap->a_runp, ap->a_runb); 82 else 83 error = ext2_bmaparray(ap->a_vp, ap->a_bn, &blkno, 84 ap->a_runp, ap->a_runb); 85 *ap->a_bnp = blkno; 86 return (error); 87 } 88 89 /* 90 * Convert the logical block number of a file to its physical block number 91 * on the disk within ext4 extents. 92 */ 93 int 94 ext4_bmapext(struct vnode *vp, int32_t bn, int64_t *bnp, int *runp, int *runb) 95 { 96 struct inode *ip; 97 struct m_ext2fs *fs; 98 struct mount *mp; 99 struct ext2mount *ump; 100 struct ext4_extent_header *ehp; 101 struct ext4_extent *ep; 102 struct ext4_extent_path *path = NULL; 103 daddr_t lbn; 104 int error, depth, maxrun = 0, bsize; 105 106 ip = VTOI(vp); 107 fs = ip->i_e2fs; 108 mp = vp->v_mount; 109 ump = VFSTOEXT2(mp); 110 lbn = bn; 111 ehp = (struct ext4_extent_header *)ip->i_data; 112 depth = le16toh(ehp->eh_depth); 113 bsize = EXT2_BLOCK_SIZE(ump->um_e2fs); 114 115 *bnp = -1; 116 if (runp != NULL) { 117 maxrun = mp->mnt_iosize_max / bsize - 1; 118 *runp = 0; 119 } 120 if (runb != NULL) 121 *runb = 0; 122 123 error = ext4_ext_find_extent(ip, lbn, &path); 124 if (error) 125 return (error); 126 127 ep = path[depth].ep_ext; 128 if(ep) { 129 if (lbn < le32toh(ep->e_blk)) { 130 if (runp != NULL) { 131 *runp = min(maxrun, le32toh(ep->e_blk) - lbn - 1); 132 } 133 } else if (le32toh(ep->e_blk) <= lbn && 134 lbn < le32toh(ep->e_blk) + le16toh(ep->e_len)) { 135 *bnp = fsbtodb(fs, lbn - le32toh(ep->e_blk) + 136 (le32toh(ep->e_start_lo) | 137 (daddr_t)le16toh(ep->e_start_hi) << 32)); 138 if (runp != NULL) { 139 *runp = min(maxrun, 140 le16toh(ep->e_len) - 141 (lbn - le32toh(ep->e_blk)) - 1); 142 } 143 if (runb != NULL) 144 *runb = min(maxrun, lbn - le32toh(ep->e_blk)); 145 } else { 146 if (runb != NULL) 147 *runb = min(maxrun, le32toh(ep->e_blk) + lbn - 148 le16toh(ep->e_len)); 149 } 150 } 151 152 ext4_ext_path_free(path); 153 154 return (error); 155 } 156 157 static int 158 readindir(struct vnode *vp, e2fs_lbn_t lbn, e2fs_daddr_t daddr, struct buf **bpp) 159 { 160 struct buf *bp; 161 struct mount *mp; 162 struct ext2mount *ump; 163 int error; 164 165 mp = vp->v_mount; 166 ump = VFSTOEXT2(mp); 167 168 bp = getblk(vp, lbn, mp->mnt_stat.f_iosize, 0, 0, 0); 169 if ((bp->b_flags & B_CACHE) == 0) { 170 KASSERT(daddr != 0, 171 ("readindir: indirect block not in cache")); 172 173 bp->b_blkno = blkptrtodb(ump, daddr); 174 bp->b_iocmd = BIO_READ; 175 bp->b_flags &= ~B_INVAL; 176 bp->b_ioflags &= ~BIO_ERROR; 177 vfs_busy_pages(bp, 0); 178 bp->b_iooffset = dbtob(bp->b_blkno); 179 bstrategy(bp); 180 #ifdef RACCT 181 if (racct_enable) { 182 PROC_LOCK(curproc); 183 racct_add_buf(curproc, bp, 0); 184 PROC_UNLOCK(curproc); 185 } 186 #endif 187 curthread->td_ru.ru_inblock++; 188 error = bufwait(bp); 189 if (error != 0) { 190 brelse(bp); 191 return (error); 192 } 193 } 194 *bpp = bp; 195 return (0); 196 } 197 198 /* 199 * Indirect blocks are now on the vnode for the file. They are given negative 200 * logical block numbers. Indirect blocks are addressed by the negative 201 * address of the first data block to which they point. Double indirect blocks 202 * are addressed by one less than the address of the first indirect block to 203 * which they point. Triple indirect blocks are addressed by one less than 204 * the address of the first double indirect block to which they point. 205 * 206 * ext2_bmaparray does the bmap conversion, and if requested returns the 207 * array of logical blocks which must be traversed to get to a block. 208 * Each entry contains the offset into that block that gets you to the 209 * next block and the disk address of the block (if it is assigned). 210 */ 211 212 int 213 ext2_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *bnp, int *runp, int *runb) 214 { 215 struct inode *ip; 216 struct buf *bp; 217 struct ext2mount *ump; 218 struct mount *mp; 219 struct indir a[EXT2_NIADDR + 1], *ap; 220 daddr_t daddr; 221 e2fs_lbn_t metalbn; 222 int error, num, maxrun = 0, bsize; 223 int *nump; 224 225 ap = NULL; 226 ip = VTOI(vp); 227 mp = vp->v_mount; 228 ump = VFSTOEXT2(mp); 229 230 bsize = EXT2_BLOCK_SIZE(ump->um_e2fs); 231 232 if (runp) { 233 maxrun = mp->mnt_iosize_max / bsize - 1; 234 *runp = 0; 235 } 236 if (runb) 237 *runb = 0; 238 239 ap = a; 240 nump = # 241 error = ext2_getlbns(vp, bn, ap, nump); 242 if (error) 243 return (error); 244 245 num = *nump; 246 if (num == 0) { 247 *bnp = blkptrtodb(ump, ip->i_db[bn]); 248 if (*bnp == 0) { 249 *bnp = -1; 250 } else if (runp) { 251 daddr_t bnb = bn; 252 253 for (++bn; bn < EXT2_NDADDR && *runp < maxrun && 254 is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]); 255 ++bn, ++*runp); 256 bn = bnb; 257 if (runb && (bn > 0)) { 258 for (--bn; (bn >= 0) && (*runb < maxrun) && 259 is_sequential(ump, ip->i_db[bn], 260 ip->i_db[bn + 1]); 261 --bn, ++*runb); 262 } 263 } 264 return (0); 265 } 266 267 /* Get disk address out of indirect block array */ 268 daddr = ip->i_ib[ap->in_off]; 269 270 for (bp = NULL, ++ap; --num; ++ap) { 271 /* 272 * Exit the loop if there is no disk address assigned yet and 273 * the indirect block isn't in the cache, or if we were 274 * looking for an indirect block and we've found it. 275 */ 276 277 metalbn = ap->in_lbn; 278 if ((daddr == 0 && !incore(&vp->v_bufobj, metalbn)) || metalbn == bn) 279 break; 280 /* 281 * If we get here, we've either got the block in the cache 282 * or we have a disk address for it, go fetch it. 283 */ 284 if (bp) 285 bqrelse(bp); 286 error = readindir(vp, metalbn, daddr, &bp); 287 if (error != 0) 288 return (error); 289 290 daddr = le32toh(((e2fs_daddr_t *)bp->b_data)[ap->in_off]); 291 if (num == 1 && daddr && runp) { 292 for (bn = ap->in_off + 1; 293 bn < MNINDIR(ump) && *runp < maxrun && 294 is_sequential(ump, 295 ((e2fs_daddr_t *)bp->b_data)[bn - 1], 296 ((e2fs_daddr_t *)bp->b_data)[bn]); 297 ++bn, ++*runp); 298 bn = ap->in_off; 299 if (runb && bn) { 300 for (--bn; bn >= 0 && *runb < maxrun && 301 is_sequential(ump, 302 ((e2fs_daddr_t *)bp->b_data)[bn], 303 ((e2fs_daddr_t *)bp->b_data)[bn + 1]); 304 --bn, ++*runb); 305 } 306 } 307 } 308 if (bp) 309 bqrelse(bp); 310 311 *bnp = blkptrtodb(ump, daddr); 312 if (*bnp == 0) { 313 *bnp = -1; 314 } 315 return (0); 316 } 317 318 static e2fs_lbn_t 319 lbn_count(struct ext2mount *ump, int level) 320 321 { 322 e2fs_lbn_t blockcnt; 323 324 for (blockcnt = 1; level > 0; level--) 325 blockcnt *= MNINDIR(ump); 326 return (blockcnt); 327 } 328 329 int 330 ext2_bmap_seekdata(struct vnode *vp, off_t *offp) 331 { 332 struct buf *bp; 333 struct indir a[EXT2_NIADDR + 1], *ap; 334 struct inode *ip; 335 struct mount *mp; 336 struct ext2mount *ump; 337 e2fs_daddr_t bn, daddr, nextbn; 338 uint64_t bsize; 339 off_t numblks; 340 int error, num, num1, off; 341 342 bp = NULL; 343 error = 0; 344 ip = VTOI(vp); 345 mp = vp->v_mount; 346 ump = VFSTOEXT2(mp); 347 348 if (vp->v_type != VREG) 349 return (EINVAL); 350 if (*offp < 0 || *offp >= ip->i_size) 351 return (ENXIO); 352 353 bsize = mp->mnt_stat.f_iosize; 354 for (bn = *offp / bsize, numblks = howmany(ip->i_size, bsize); 355 bn < numblks; bn = nextbn) { 356 if (bn < EXT2_NDADDR) { 357 daddr = ip->i_db[bn]; 358 if (daddr != 0) 359 break; 360 nextbn = bn + 1; 361 continue; 362 } 363 364 ap = a; 365 error = ext2_getlbns(vp, bn, ap, &num); 366 if (error != 0) 367 break; 368 MPASS(num >= 2); 369 daddr = ip->i_ib[ap->in_off]; 370 ap++, num--; 371 for (nextbn = EXT2_NDADDR, num1 = num - 1; num1 > 0; num1--) 372 nextbn += lbn_count(ump, num1); 373 if (daddr == 0) { 374 nextbn += lbn_count(ump, num); 375 continue; 376 } 377 378 for (; daddr != 0 && num > 0; ap++, num--) { 379 if (bp != NULL) 380 bqrelse(bp); 381 error = readindir(vp, ap->in_lbn, daddr, &bp); 382 if (error != 0) 383 return (error); 384 385 /* 386 * Scan the indirect block until we find a non-zero 387 * pointer. 388 */ 389 off = ap->in_off; 390 do { 391 daddr = le32toh(((e2fs_daddr_t *)bp->b_data)[off]); 392 } while (daddr == 0 && ++off < MNINDIR(ump)); 393 nextbn += off * lbn_count(ump, num - 1); 394 395 /* 396 * We need to recompute the LBNs of indirect 397 * blocks, so restart with the updated block offset. 398 */ 399 if (off != ap->in_off) 400 break; 401 } 402 if (num == 0) { 403 /* 404 * We found a data block. 405 */ 406 bn = nextbn; 407 break; 408 } 409 } 410 if (bp != NULL) 411 bqrelse(bp); 412 if (bn >= numblks) 413 error = ENXIO; 414 if (error == 0 && *offp < bn * bsize) 415 *offp = bn * bsize; 416 return (error); 417 } 418 419 /* 420 * Create an array of logical block number/offset pairs which represent the 421 * path of indirect blocks required to access a data block. The first "pair" 422 * contains the logical block number of the appropriate single, double or 423 * triple indirect block and the offset into the inode indirect block array. 424 * Note, the logical block number of the inode single/double/triple indirect 425 * block appears twice in the array, once with the offset into the i_ib and 426 * once with the offset into the page itself. 427 */ 428 int 429 ext2_getlbns(struct vnode *vp, daddr_t bn, struct indir *ap, int *nump) 430 { 431 long blockcnt; 432 e2fs_lbn_t metalbn, realbn; 433 struct ext2mount *ump; 434 int i, numlevels, off; 435 int64_t qblockcnt; 436 437 ump = VFSTOEXT2(vp->v_mount); 438 if (nump) 439 *nump = 0; 440 numlevels = 0; 441 realbn = bn; 442 if ((long)bn < 0) 443 bn = -(long)bn; 444 445 /* The first EXT2_NDADDR blocks are direct blocks. */ 446 if (bn < EXT2_NDADDR) 447 return (0); 448 449 /* 450 * Determine the number of levels of indirection. After this loop 451 * is done, blockcnt indicates the number of data blocks possible 452 * at the previous level of indirection, and EXT2_NIADDR - i is the 453 * number of levels of indirection needed to locate the requested block. 454 */ 455 for (blockcnt = 1, i = EXT2_NIADDR, bn -= EXT2_NDADDR; ; 456 i--, bn -= blockcnt) { 457 if (i == 0) 458 return (EFBIG); 459 /* 460 * Use int64_t's here to avoid overflow for triple indirect 461 * blocks when longs have 32 bits and the block size is more 462 * than 4K. 463 */ 464 qblockcnt = (int64_t)blockcnt * MNINDIR(ump); 465 if (bn < qblockcnt) 466 break; 467 blockcnt = qblockcnt; 468 } 469 470 /* Calculate the address of the first meta-block. */ 471 if (realbn >= 0) 472 metalbn = -(realbn - bn + EXT2_NIADDR - i); 473 else 474 metalbn = -(-realbn - bn + EXT2_NIADDR - i); 475 476 /* 477 * At each iteration, off is the offset into the bap array which is 478 * an array of disk addresses at the current level of indirection. 479 * The logical block number and the offset in that block are stored 480 * into the argument array. 481 */ 482 ap->in_lbn = metalbn; 483 ap->in_off = off = EXT2_NIADDR - i; 484 ap++; 485 for (++numlevels; i <= EXT2_NIADDR; i++) { 486 /* If searching for a meta-data block, quit when found. */ 487 if (metalbn == realbn) 488 break; 489 490 off = (bn / blockcnt) % MNINDIR(ump); 491 492 ++numlevels; 493 ap->in_lbn = metalbn; 494 ap->in_off = off; 495 ++ap; 496 497 metalbn -= -1 + off * blockcnt; 498 blockcnt /= MNINDIR(ump); 499 } 500 if (nump) 501 *nump = numlevels; 502 return (0); 503 } 504