1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)ffs_subr.c 8.5 (Berkeley) 3/21/95 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include <sys/param.h> 38 39 #ifndef _KERNEL 40 #include <stdio.h> 41 #include <string.h> 42 #include <stdlib.h> 43 #include <time.h> 44 #include <sys/errno.h> 45 #include <ufs/ufs/dinode.h> 46 #include <ufs/ffs/fs.h> 47 48 uint32_t calculate_crc32c(uint32_t, const void *, size_t); 49 uint32_t ffs_calc_sbhash(struct fs *); 50 struct malloc_type; 51 #define UFS_MALLOC(size, type, flags) malloc(size) 52 #define UFS_FREE(ptr, type) free(ptr) 53 #define UFS_TIME time(NULL) 54 /* 55 * Request standard superblock location in ffs_sbget 56 */ 57 #define STDSB -1 /* Fail if check-hash is bad */ 58 #define STDSB_NOHASHFAIL -2 /* Ignore check-hash failure */ 59 60 #else /* _KERNEL */ 61 #include <sys/systm.h> 62 #include <sys/gsb_crc32.h> 63 #include <sys/lock.h> 64 #include <sys/malloc.h> 65 #include <sys/mount.h> 66 #include <sys/vnode.h> 67 #include <sys/bio.h> 68 #include <sys/buf.h> 69 #include <sys/ucred.h> 70 71 #include <ufs/ufs/quota.h> 72 #include <ufs/ufs/inode.h> 73 #include <ufs/ufs/extattr.h> 74 #include <ufs/ufs/ufsmount.h> 75 #include <ufs/ufs/ufs_extern.h> 76 #include <ufs/ffs/ffs_extern.h> 77 #include <ufs/ffs/fs.h> 78 79 #define UFS_MALLOC(size, type, flags) malloc(size, type, flags) 80 #define UFS_FREE(ptr, type) free(ptr, type) 81 #define UFS_TIME time_second 82 83 /* 84 * Return buffer with the contents of block "offset" from the beginning of 85 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 86 * remaining space in the directory. 87 */ 88 int 89 ffs_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp) 90 { 91 struct inode *ip; 92 struct fs *fs; 93 struct buf *bp; 94 ufs_lbn_t lbn; 95 int bsize, error; 96 97 ip = VTOI(vp); 98 fs = ITOFS(ip); 99 lbn = lblkno(fs, offset); 100 bsize = blksize(fs, ip, lbn); 101 102 *bpp = NULL; 103 error = bread(vp, lbn, bsize, NOCRED, &bp); 104 if (error) { 105 brelse(bp); 106 return (error); 107 } 108 if (res) 109 *res = (char *)bp->b_data + blkoff(fs, offset); 110 *bpp = bp; 111 return (0); 112 } 113 114 /* 115 * Load up the contents of an inode and copy the appropriate pieces 116 * to the incore copy. 117 */ 118 int 119 ffs_load_inode(struct buf *bp, struct inode *ip, struct fs *fs, ino_t ino) 120 { 121 struct ufs1_dinode *dip1; 122 struct ufs2_dinode *dip2; 123 int error; 124 125 if (I_IS_UFS1(ip)) { 126 dip1 = ip->i_din1; 127 *dip1 = 128 *((struct ufs1_dinode *)bp->b_data + ino_to_fsbo(fs, ino)); 129 ip->i_mode = dip1->di_mode; 130 ip->i_nlink = dip1->di_nlink; 131 ip->i_effnlink = dip1->di_nlink; 132 ip->i_size = dip1->di_size; 133 ip->i_flags = dip1->di_flags; 134 ip->i_gen = dip1->di_gen; 135 ip->i_uid = dip1->di_uid; 136 ip->i_gid = dip1->di_gid; 137 return (0); 138 } 139 dip2 = ((struct ufs2_dinode *)bp->b_data + ino_to_fsbo(fs, ino)); 140 if ((error = ffs_verify_dinode_ckhash(fs, dip2)) != 0) { 141 printf("%s: inode %jd: check-hash failed\n", fs->fs_fsmnt, 142 (intmax_t)ino); 143 return (error); 144 } 145 *ip->i_din2 = *dip2; 146 dip2 = ip->i_din2; 147 ip->i_mode = dip2->di_mode; 148 ip->i_nlink = dip2->di_nlink; 149 ip->i_effnlink = dip2->di_nlink; 150 ip->i_size = dip2->di_size; 151 ip->i_flags = dip2->di_flags; 152 ip->i_gen = dip2->di_gen; 153 ip->i_uid = dip2->di_uid; 154 ip->i_gid = dip2->di_gid; 155 return (0); 156 } 157 #endif /* _KERNEL */ 158 159 /* 160 * Verify an inode check-hash. 161 */ 162 int 163 ffs_verify_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip) 164 { 165 uint32_t ckhash, save_ckhash; 166 167 /* 168 * Return success if unallocated or we are not doing inode check-hash. 169 */ 170 if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0) 171 return (0); 172 /* 173 * Exclude di_ckhash from the crc32 calculation, e.g., always use 174 * a check-hash value of zero when calculating the check-hash. 175 */ 176 save_ckhash = dip->di_ckhash; 177 dip->di_ckhash = 0; 178 ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip)); 179 dip->di_ckhash = save_ckhash; 180 if (save_ckhash == ckhash) 181 return (0); 182 return (EINVAL); 183 } 184 185 /* 186 * Update an inode check-hash. 187 */ 188 void 189 ffs_update_dinode_ckhash(struct fs *fs, struct ufs2_dinode *dip) 190 { 191 192 if (dip->di_mode == 0 || (fs->fs_metackhash & CK_INODE) == 0) 193 return; 194 /* 195 * Exclude old di_ckhash from the crc32 calculation, e.g., always use 196 * a check-hash value of zero when calculating the new check-hash. 197 */ 198 dip->di_ckhash = 0; 199 dip->di_ckhash = calculate_crc32c(~0L, (void *)dip, sizeof(*dip)); 200 } 201 202 /* 203 * These are the low-level functions that actually read and write 204 * the superblock and its associated data. 205 */ 206 static off_t sblock_try[] = SBLOCKSEARCH; 207 static int readsuper(void *, struct fs **, off_t, int, int, 208 int (*)(void *, off_t, void **, int)); 209 210 /* 211 * Read a superblock from the devfd device. 212 * 213 * If an alternate superblock is specified, it is read. Otherwise the 214 * set of locations given in the SBLOCKSEARCH list is searched for a 215 * superblock. Memory is allocated for the superblock by the readfunc and 216 * is returned. If filltype is non-NULL, additional memory is allocated 217 * of type filltype and filled in with the superblock summary information. 218 * All memory is freed when any error is returned. 219 * 220 * If a superblock is found, zero is returned. Otherwise one of the 221 * following error values is returned: 222 * EIO: non-existent or truncated superblock. 223 * EIO: error reading summary information. 224 * ENOENT: no usable known superblock found. 225 * ENOSPC: failed to allocate space for the superblock. 226 * EINVAL: The previous newfs operation on this volume did not complete. 227 * The administrator must complete newfs before using this volume. 228 */ 229 int 230 ffs_sbget(void *devfd, struct fs **fsp, off_t altsblock, 231 struct malloc_type *filltype, 232 int (*readfunc)(void *devfd, off_t loc, void **bufp, int size)) 233 { 234 struct fs *fs; 235 int i, error, size, blks; 236 uint8_t *space; 237 int32_t *lp; 238 int chkhash; 239 char *buf; 240 241 fs = NULL; 242 *fsp = NULL; 243 chkhash = 1; 244 if (altsblock >= 0) { 245 if ((error = readsuper(devfd, &fs, altsblock, 1, chkhash, 246 readfunc)) != 0) { 247 if (fs != NULL) 248 UFS_FREE(fs, filltype); 249 return (error); 250 } 251 } else { 252 if (altsblock == STDSB_NOHASHFAIL) 253 chkhash = 0; 254 for (i = 0; sblock_try[i] != -1; i++) { 255 if ((error = readsuper(devfd, &fs, sblock_try[i], 0, 256 chkhash, readfunc)) == 0) 257 break; 258 if (fs != NULL) { 259 UFS_FREE(fs, filltype); 260 fs = NULL; 261 } 262 if (error == ENOENT) 263 continue; 264 return (error); 265 } 266 if (sblock_try[i] == -1) 267 return (ENOENT); 268 } 269 /* 270 * Read in the superblock summary information. 271 */ 272 size = fs->fs_cssize; 273 blks = howmany(size, fs->fs_fsize); 274 if (fs->fs_contigsumsize > 0) 275 size += fs->fs_ncg * sizeof(int32_t); 276 size += fs->fs_ncg * sizeof(u_int8_t); 277 /* When running in libufs or libsa, UFS_MALLOC may fail */ 278 if ((space = UFS_MALLOC(size, filltype, M_WAITOK)) == NULL) { 279 UFS_FREE(fs, filltype); 280 return (ENOSPC); 281 } 282 fs->fs_csp = (struct csum *)space; 283 for (i = 0; i < blks; i += fs->fs_frag) { 284 size = fs->fs_bsize; 285 if (i + fs->fs_frag > blks) 286 size = (blks - i) * fs->fs_fsize; 287 buf = NULL; 288 error = (*readfunc)(devfd, 289 dbtob(fsbtodb(fs, fs->fs_csaddr + i)), (void **)&buf, size); 290 if (error) { 291 if (buf != NULL) 292 UFS_FREE(buf, filltype); 293 UFS_FREE(fs->fs_csp, filltype); 294 UFS_FREE(fs, filltype); 295 return (error); 296 } 297 memcpy(space, buf, size); 298 UFS_FREE(buf, filltype); 299 space += size; 300 } 301 if (fs->fs_contigsumsize > 0) { 302 fs->fs_maxcluster = lp = (int32_t *)space; 303 for (i = 0; i < fs->fs_ncg; i++) 304 *lp++ = fs->fs_contigsumsize; 305 space = (uint8_t *)lp; 306 } 307 size = fs->fs_ncg * sizeof(u_int8_t); 308 fs->fs_contigdirs = (u_int8_t *)space; 309 bzero(fs->fs_contigdirs, size); 310 *fsp = fs; 311 return (0); 312 } 313 314 /* 315 * Try to read a superblock from the location specified by sblockloc. 316 * Return zero on success or an errno on failure. 317 */ 318 static int 319 readsuper(void *devfd, struct fs **fsp, off_t sblockloc, int isaltsblk, 320 int chkhash, int (*readfunc)(void *devfd, off_t loc, void **bufp, int size)) 321 { 322 struct fs *fs; 323 int error, res; 324 uint32_t ckhash; 325 326 error = (*readfunc)(devfd, sblockloc, (void **)fsp, SBLOCKSIZE); 327 if (error != 0) 328 return (error); 329 fs = *fsp; 330 if (fs->fs_magic == FS_BAD_MAGIC) 331 return (EINVAL); 332 if (((fs->fs_magic == FS_UFS1_MAGIC && (isaltsblk || 333 sblockloc <= SBLOCK_UFS1)) || 334 (fs->fs_magic == FS_UFS2_MAGIC && (isaltsblk || 335 sblockloc == fs->fs_sblockloc))) && 336 fs->fs_ncg >= 1 && 337 fs->fs_bsize >= MINBSIZE && 338 fs->fs_bsize <= MAXBSIZE && 339 fs->fs_bsize >= roundup(sizeof(struct fs), DEV_BSIZE) && 340 fs->fs_sbsize <= SBLOCKSIZE) { 341 /* 342 * If the filesystem has been run on a kernel without 343 * metadata check hashes, disable them. 344 */ 345 if ((fs->fs_flags & FS_METACKHASH) == 0) 346 fs->fs_metackhash = 0; 347 if (fs->fs_ckhash != (ckhash = ffs_calc_sbhash(fs))) { 348 #ifdef _KERNEL 349 res = uprintf("Superblock check-hash failed: recorded " 350 "check-hash 0x%x != computed check-hash 0x%x%s\n", 351 fs->fs_ckhash, ckhash, 352 chkhash == 0 ? " (Ignored)" : ""); 353 #else 354 res = 0; 355 #endif 356 /* 357 * Print check-hash failure if no controlling terminal 358 * in kernel or always if in user-mode (libufs). 359 */ 360 if (res == 0) 361 printf("Superblock check-hash failed: recorded " 362 "check-hash 0x%x != computed check-hash " 363 "0x%x%s\n", fs->fs_ckhash, ckhash, 364 chkhash == 0 ? " (Ignored)" : ""); 365 if (chkhash == 0) { 366 fs->fs_flags |= FS_NEEDSFSCK; 367 fs->fs_fmod = 1; 368 return (0); 369 } 370 fs->fs_fmod = 0; 371 return (EINVAL); 372 } 373 /* Have to set for old filesystems that predate this field */ 374 fs->fs_sblockactualloc = sblockloc; 375 /* Not yet any summary information */ 376 fs->fs_csp = NULL; 377 return (0); 378 } 379 return (ENOENT); 380 } 381 382 /* 383 * Write a superblock to the devfd device from the memory pointed to by fs. 384 * Write out the superblock summary information if it is present. 385 * 386 * If the write is successful, zero is returned. Otherwise one of the 387 * following error values is returned: 388 * EIO: failed to write superblock. 389 * EIO: failed to write superblock summary information. 390 */ 391 int 392 ffs_sbput(void *devfd, struct fs *fs, off_t loc, 393 int (*writefunc)(void *devfd, off_t loc, void *buf, int size)) 394 { 395 int i, error, blks, size; 396 uint8_t *space; 397 398 /* 399 * If there is summary information, write it first, so if there 400 * is an error, the superblock will not be marked as clean. 401 */ 402 if (fs->fs_csp != NULL) { 403 blks = howmany(fs->fs_cssize, fs->fs_fsize); 404 space = (uint8_t *)fs->fs_csp; 405 for (i = 0; i < blks; i += fs->fs_frag) { 406 size = fs->fs_bsize; 407 if (i + fs->fs_frag > blks) 408 size = (blks - i) * fs->fs_fsize; 409 if ((error = (*writefunc)(devfd, 410 dbtob(fsbtodb(fs, fs->fs_csaddr + i)), 411 space, size)) != 0) 412 return (error); 413 space += size; 414 } 415 } 416 fs->fs_fmod = 0; 417 fs->fs_time = UFS_TIME; 418 fs->fs_ckhash = ffs_calc_sbhash(fs); 419 if ((error = (*writefunc)(devfd, loc, fs, fs->fs_sbsize)) != 0) 420 return (error); 421 return (0); 422 } 423 424 /* 425 * Calculate the check-hash for a superblock. 426 */ 427 uint32_t 428 ffs_calc_sbhash(struct fs *fs) 429 { 430 uint32_t ckhash, save_ckhash; 431 432 /* 433 * A filesystem that was using a superblock ckhash may be moved 434 * to an older kernel that does not support ckhashes. The 435 * older kernel will clear the FS_METACKHASH flag indicating 436 * that it does not update hashes. When the disk is moved back 437 * to a kernel capable of ckhashes it disables them on mount: 438 * 439 * if ((fs->fs_flags & FS_METACKHASH) == 0) 440 * fs->fs_metackhash = 0; 441 * 442 * This leaves (fs->fs_metackhash & CK_SUPERBLOCK) == 0) with an 443 * old stale value in the fs->fs_ckhash field. Thus the need to 444 * just accept what is there. 445 */ 446 if ((fs->fs_metackhash & CK_SUPERBLOCK) == 0) 447 return (fs->fs_ckhash); 448 449 save_ckhash = fs->fs_ckhash; 450 fs->fs_ckhash = 0; 451 /* 452 * If newly read from disk, the caller is responsible for 453 * verifying that fs->fs_sbsize <= SBLOCKSIZE. 454 */ 455 ckhash = calculate_crc32c(~0L, (void *)fs, fs->fs_sbsize); 456 fs->fs_ckhash = save_ckhash; 457 return (ckhash); 458 } 459 460 /* 461 * Update the frsum fields to reflect addition or deletion 462 * of some frags. 463 */ 464 void 465 ffs_fragacct(struct fs *fs, int fragmap, int32_t fraglist[], int cnt) 466 { 467 int inblk; 468 int field, subfield; 469 int siz, pos; 470 471 inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1; 472 fragmap <<= 1; 473 for (siz = 1; siz < fs->fs_frag; siz++) { 474 if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0) 475 continue; 476 field = around[siz]; 477 subfield = inside[siz]; 478 for (pos = siz; pos <= fs->fs_frag; pos++) { 479 if ((fragmap & field) == subfield) { 480 fraglist[siz] += cnt; 481 pos += siz; 482 field <<= siz; 483 subfield <<= siz; 484 } 485 field <<= 1; 486 subfield <<= 1; 487 } 488 } 489 } 490 491 /* 492 * block operations 493 * 494 * check if a block is available 495 */ 496 int 497 ffs_isblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h) 498 { 499 unsigned char mask; 500 501 switch ((int)fs->fs_frag) { 502 case 8: 503 return (cp[h] == 0xff); 504 case 4: 505 mask = 0x0f << ((h & 0x1) << 2); 506 return ((cp[h >> 1] & mask) == mask); 507 case 2: 508 mask = 0x03 << ((h & 0x3) << 1); 509 return ((cp[h >> 2] & mask) == mask); 510 case 1: 511 mask = 0x01 << (h & 0x7); 512 return ((cp[h >> 3] & mask) == mask); 513 default: 514 #ifdef _KERNEL 515 panic("ffs_isblock"); 516 #endif 517 break; 518 } 519 return (0); 520 } 521 522 /* 523 * check if a block is free 524 */ 525 int 526 ffs_isfreeblock(struct fs *fs, u_char *cp, ufs1_daddr_t h) 527 { 528 529 switch ((int)fs->fs_frag) { 530 case 8: 531 return (cp[h] == 0); 532 case 4: 533 return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0); 534 case 2: 535 return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0); 536 case 1: 537 return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0); 538 default: 539 #ifdef _KERNEL 540 panic("ffs_isfreeblock"); 541 #endif 542 break; 543 } 544 return (0); 545 } 546 547 /* 548 * take a block out of the map 549 */ 550 void 551 ffs_clrblock(struct fs *fs, u_char *cp, ufs1_daddr_t h) 552 { 553 554 switch ((int)fs->fs_frag) { 555 case 8: 556 cp[h] = 0; 557 return; 558 case 4: 559 cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2)); 560 return; 561 case 2: 562 cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1)); 563 return; 564 case 1: 565 cp[h >> 3] &= ~(0x01 << (h & 0x7)); 566 return; 567 default: 568 #ifdef _KERNEL 569 panic("ffs_clrblock"); 570 #endif 571 break; 572 } 573 } 574 575 /* 576 * put a block into the map 577 */ 578 void 579 ffs_setblock(struct fs *fs, unsigned char *cp, ufs1_daddr_t h) 580 { 581 582 switch ((int)fs->fs_frag) { 583 584 case 8: 585 cp[h] = 0xff; 586 return; 587 case 4: 588 cp[h >> 1] |= (0x0f << ((h & 0x1) << 2)); 589 return; 590 case 2: 591 cp[h >> 2] |= (0x03 << ((h & 0x3) << 1)); 592 return; 593 case 1: 594 cp[h >> 3] |= (0x01 << (h & 0x7)); 595 return; 596 default: 597 #ifdef _KERNEL 598 panic("ffs_setblock"); 599 #endif 600 break; 601 } 602 } 603 604 /* 605 * Update the cluster map because of an allocation or free. 606 * 607 * Cnt == 1 means free; cnt == -1 means allocating. 608 */ 609 void 610 ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs1_daddr_t blkno, int cnt) 611 { 612 int32_t *sump; 613 int32_t *lp; 614 u_char *freemapp, *mapp; 615 int i, start, end, forw, back, map; 616 u_int bit; 617 618 if (fs->fs_contigsumsize <= 0) 619 return; 620 freemapp = cg_clustersfree(cgp); 621 sump = cg_clustersum(cgp); 622 /* 623 * Allocate or clear the actual block. 624 */ 625 if (cnt > 0) 626 setbit(freemapp, blkno); 627 else 628 clrbit(freemapp, blkno); 629 /* 630 * Find the size of the cluster going forward. 631 */ 632 start = blkno + 1; 633 end = start + fs->fs_contigsumsize; 634 if (end >= cgp->cg_nclusterblks) 635 end = cgp->cg_nclusterblks; 636 mapp = &freemapp[start / NBBY]; 637 map = *mapp++; 638 bit = 1U << (start % NBBY); 639 for (i = start; i < end; i++) { 640 if ((map & bit) == 0) 641 break; 642 if ((i & (NBBY - 1)) != (NBBY - 1)) { 643 bit <<= 1; 644 } else { 645 map = *mapp++; 646 bit = 1; 647 } 648 } 649 forw = i - start; 650 /* 651 * Find the size of the cluster going backward. 652 */ 653 start = blkno - 1; 654 end = start - fs->fs_contigsumsize; 655 if (end < 0) 656 end = -1; 657 mapp = &freemapp[start / NBBY]; 658 map = *mapp--; 659 bit = 1U << (start % NBBY); 660 for (i = start; i > end; i--) { 661 if ((map & bit) == 0) 662 break; 663 if ((i & (NBBY - 1)) != 0) { 664 bit >>= 1; 665 } else { 666 map = *mapp--; 667 bit = 1U << (NBBY - 1); 668 } 669 } 670 back = start - i; 671 /* 672 * Account for old cluster and the possibly new forward and 673 * back clusters. 674 */ 675 i = back + forw + 1; 676 if (i > fs->fs_contigsumsize) 677 i = fs->fs_contigsumsize; 678 sump[i] += cnt; 679 if (back > 0) 680 sump[back] -= cnt; 681 if (forw > 0) 682 sump[forw] -= cnt; 683 /* 684 * Update cluster summary information. 685 */ 686 lp = &sump[fs->fs_contigsumsize]; 687 for (i = fs->fs_contigsumsize; i > 0; i--) 688 if (*lp-- > 0) 689 break; 690 fs->fs_maxcluster[cgp->cg_cgx] = i; 691 } 692