1/* $NetBSD: ffs_alloc.c,v 1.14 2004/06/20 22:20:18 jmc Exp $ */ 2/* From: NetBSD: ffs_alloc.c,v 1.50 2001/09/06 02:16:01 lukem Exp */ 3 4/* 5 * Copyright (c) 2002 Networks Associates Technology, Inc. 6 * All rights reserved. 7 * 8 * This software was developed for the FreeBSD Project by Marshall 9 * Kirk McKusick and Network Associates Laboratories, the Security 10 * Research Division of Network Associates, Inc. under DARPA/SPAWAR 11 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS 12 * research program 13 * 14 * Copyright (c) 1982, 1986, 1989, 1993 15 * The Regents of the University of California. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 3. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)ffs_alloc.c 8.19 (Berkeley) 7/13/95 42 */ 43 44#include <sys/cdefs.h> 45__FBSDID("$FreeBSD: releng/10.2/usr.sbin/makefs/ffs/ffs_alloc.c 241015 2012-09-27 23:31:19Z mdf $"); 46 47#include <sys/param.h> 48#include <sys/time.h> 49 50#include <errno.h> 51#include <stdint.h> 52 53#include "makefs.h" 54 55#include <ufs/ufs/dinode.h> 56#include <ufs/ffs/fs.h> 57 58#include "ffs/ufs_bswap.h" 59#include "ffs/buf.h" 60#include "ffs/ufs_inode.h" 61#include "ffs/ffs_extern.h" 62 63static int scanc(u_int, const u_char *, const u_char *, int); 64 65static daddr_t ffs_alloccg(struct inode *, int, daddr_t, int); 66static daddr_t ffs_alloccgblk(struct inode *, struct buf *, daddr_t); 67static daddr_t ffs_hashalloc(struct inode *, int, daddr_t, int, 68 daddr_t (*)(struct inode *, int, daddr_t, int)); 69static int32_t ffs_mapsearch(struct fs *, struct cg *, daddr_t, int); 70 71/* 72 * Allocate a block in the file system. 73 * 74 * The size of the requested block is given, which must be some 75 * multiple of fs_fsize and <= fs_bsize. 76 * A preference may be optionally specified. If a preference is given 77 * the following hierarchy is used to allocate a block: 78 * 1) allocate the requested block. 79 * 2) allocate a rotationally optimal block in the same cylinder. 80 * 3) allocate a block in the same cylinder group. 81 * 4) quadradically rehash into other cylinder groups, until an 82 * available block is located. 83 * If no block preference is given the following hierarchy is used 84 * to allocate a block: 85 * 1) allocate a block in the cylinder group that contains the 86 * inode for the file. 87 * 2) quadradically rehash into other cylinder groups, until an 88 * available block is located. 89 */ 90int 91ffs_alloc(struct inode *ip, daddr_t lbn __unused, daddr_t bpref, int size, 92 daddr_t *bnp) 93{ 94 struct fs *fs = ip->i_fs; 95 daddr_t bno; 96 int cg; 97 98 *bnp = 0; 99 if (size > fs->fs_bsize || fragoff(fs, size) != 0) { 100 errx(1, "ffs_alloc: bad size: bsize %d size %d", 101 fs->fs_bsize, size); 102 } 103 if (size == fs->fs_bsize && fs->fs_cstotal.cs_nbfree == 0) 104 goto nospace; 105 if (bpref >= fs->fs_size) 106 bpref = 0; 107 if (bpref == 0) 108 cg = ino_to_cg(fs, ip->i_number); 109 else 110 cg = dtog(fs, bpref); 111 bno = ffs_hashalloc(ip, cg, bpref, size, ffs_alloccg); 112 if (bno > 0) { 113 if (ip->i_fs->fs_magic == FS_UFS1_MAGIC) 114 ip->i_ffs1_blocks += size / DEV_BSIZE; 115 else 116 ip->i_ffs2_blocks += size / DEV_BSIZE; 117 *bnp = bno; 118 return (0); 119 } 120nospace: 121 return (ENOSPC); 122} 123 124/* 125 * Select the desired position for the next block in a file. The file is 126 * logically divided into sections. The first section is composed of the 127 * direct blocks. Each additional section contains fs_maxbpg blocks. 128 * 129 * If no blocks have been allocated in the first section, the policy is to 130 * request a block in the same cylinder group as the inode that describes 131 * the file. If no blocks have been allocated in any other section, the 132 * policy is to place the section in a cylinder group with a greater than 133 * average number of free blocks. An appropriate cylinder group is found 134 * by using a rotor that sweeps the cylinder groups. When a new group of 135 * blocks is needed, the sweep begins in the cylinder group following the 136 * cylinder group from which the previous allocation was made. The sweep 137 * continues until a cylinder group with greater than the average number 138 * of free blocks is found. If the allocation is for the first block in an 139 * indirect block, the information on the previous allocation is unavailable; 140 * here a best guess is made based upon the logical block number being 141 * allocated. 142 * 143 * If a section is already partially allocated, the policy is to 144 * contiguously allocate fs_maxcontig blocks. The end of one of these 145 * contiguous blocks and the beginning of the next is physically separated 146 * so that the disk head will be in transit between them for at least 147 * fs_rotdelay milliseconds. This is to allow time for the processor to 148 * schedule another I/O transfer. 149 */ 150/* XXX ondisk32 */ 151daddr_t 152ffs_blkpref_ufs1(struct inode *ip, daddr_t lbn, int indx, int32_t *bap) 153{ 154 struct fs *fs; 155 int cg; 156 int avgbfree, startcg; 157 158 fs = ip->i_fs; 159 if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) { 160 if (lbn < NDADDR + NINDIR(fs)) { 161 cg = ino_to_cg(fs, ip->i_number); 162 return (fs->fs_fpg * cg + fs->fs_frag); 163 } 164 /* 165 * Find a cylinder with greater than average number of 166 * unused data blocks. 167 */ 168 if (indx == 0 || bap[indx - 1] == 0) 169 startcg = 170 ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg; 171 else 172 startcg = dtog(fs, 173 ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 1); 174 startcg %= fs->fs_ncg; 175 avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg; 176 for (cg = startcg; cg < fs->fs_ncg; cg++) 177 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) 178 return (fs->fs_fpg * cg + fs->fs_frag); 179 for (cg = 0; cg <= startcg; cg++) 180 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) 181 return (fs->fs_fpg * cg + fs->fs_frag); 182 return (0); 183 } 184 /* 185 * We just always try to lay things out contiguously. 186 */ 187 return ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag; 188} 189 190daddr_t 191ffs_blkpref_ufs2(struct inode *ip, daddr_t lbn, int indx, int64_t *bap) 192{ 193 struct fs *fs; 194 int cg; 195 int avgbfree, startcg; 196 197 fs = ip->i_fs; 198 if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) { 199 if (lbn < NDADDR + NINDIR(fs)) { 200 cg = ino_to_cg(fs, ip->i_number); 201 return (fs->fs_fpg * cg + fs->fs_frag); 202 } 203 /* 204 * Find a cylinder with greater than average number of 205 * unused data blocks. 206 */ 207 if (indx == 0 || bap[indx - 1] == 0) 208 startcg = 209 ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg; 210 else 211 startcg = dtog(fs, 212 ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 1); 213 startcg %= fs->fs_ncg; 214 avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg; 215 for (cg = startcg; cg < fs->fs_ncg; cg++) 216 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) { 217 return (fs->fs_fpg * cg + fs->fs_frag); 218 } 219 for (cg = 0; cg < startcg; cg++) 220 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) { 221 return (fs->fs_fpg * cg + fs->fs_frag); 222 } 223 return (0); 224 } 225 /* 226 * We just always try to lay things out contiguously. 227 */ 228 return ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag; 229} 230 231/* 232 * Implement the cylinder overflow algorithm. 233 * 234 * The policy implemented by this algorithm is: 235 * 1) allocate the block in its requested cylinder group. 236 * 2) quadradically rehash on the cylinder group number. 237 * 3) brute force search for a free block. 238 * 239 * `size': size for data blocks, mode for inodes 240 */ 241/*VARARGS5*/ 242static daddr_t 243ffs_hashalloc(struct inode *ip, int cg, daddr_t pref, int size, 244 daddr_t (*allocator)(struct inode *, int, daddr_t, int)) 245{ 246 struct fs *fs; 247 daddr_t result; 248 int i, icg = cg; 249 250 fs = ip->i_fs; 251 /* 252 * 1: preferred cylinder group 253 */ 254 result = (*allocator)(ip, cg, pref, size); 255 if (result) 256 return (result); 257 /* 258 * 2: quadratic rehash 259 */ 260 for (i = 1; i < fs->fs_ncg; i *= 2) { 261 cg += i; 262 if (cg >= fs->fs_ncg) 263 cg -= fs->fs_ncg; 264 result = (*allocator)(ip, cg, 0, size); 265 if (result) 266 return (result); 267 } 268 /* 269 * 3: brute force search 270 * Note that we start at i == 2, since 0 was checked initially, 271 * and 1 is always checked in the quadratic rehash. 272 */ 273 cg = (icg + 2) % fs->fs_ncg; 274 for (i = 2; i < fs->fs_ncg; i++) { 275 result = (*allocator)(ip, cg, 0, size); 276 if (result) 277 return (result); 278 cg++; 279 if (cg == fs->fs_ncg) 280 cg = 0; 281 } 282 return (0); 283} 284 285/* 286 * Determine whether a block can be allocated. 287 * 288 * Check to see if a block of the appropriate size is available, 289 * and if it is, allocate it. 290 */ 291static daddr_t 292ffs_alloccg(struct inode *ip, int cg, daddr_t bpref, int size) 293{ 294 struct cg *cgp; 295 struct buf *bp; 296 daddr_t bno, blkno; 297 int error, frags, allocsiz, i; 298 struct fs *fs = ip->i_fs; 299 const int needswap = UFS_FSNEEDSWAP(fs); 300 301 if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize) 302 return (0); 303 error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)), 304 (int)fs->fs_cgsize, &bp); 305 if (error) { 306 brelse(bp); 307 return (0); 308 } 309 cgp = (struct cg *)bp->b_data; 310 if (!cg_chkmagic_swap(cgp, needswap) || 311 (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize)) { 312 brelse(bp); 313 return (0); 314 } 315 if (size == fs->fs_bsize) { 316 bno = ffs_alloccgblk(ip, bp, bpref); 317 bdwrite(bp); 318 return (bno); 319 } 320 /* 321 * check to see if any fragments are already available 322 * allocsiz is the size which will be allocated, hacking 323 * it down to a smaller size if necessary 324 */ 325 frags = numfrags(fs, size); 326 for (allocsiz = frags; allocsiz < fs->fs_frag; allocsiz++) 327 if (cgp->cg_frsum[allocsiz] != 0) 328 break; 329 if (allocsiz == fs->fs_frag) { 330 /* 331 * no fragments were available, so a block will be 332 * allocated, and hacked up 333 */ 334 if (cgp->cg_cs.cs_nbfree == 0) { 335 brelse(bp); 336 return (0); 337 } 338 bno = ffs_alloccgblk(ip, bp, bpref); 339 bpref = dtogd(fs, bno); 340 for (i = frags; i < fs->fs_frag; i++) 341 setbit(cg_blksfree_swap(cgp, needswap), bpref + i); 342 i = fs->fs_frag - frags; 343 ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); 344 fs->fs_cstotal.cs_nffree += i; 345 fs->fs_cs(fs, cg).cs_nffree += i; 346 fs->fs_fmod = 1; 347 ufs_add32(cgp->cg_frsum[i], 1, needswap); 348 bdwrite(bp); 349 return (bno); 350 } 351 bno = ffs_mapsearch(fs, cgp, bpref, allocsiz); 352 for (i = 0; i < frags; i++) 353 clrbit(cg_blksfree_swap(cgp, needswap), bno + i); 354 ufs_add32(cgp->cg_cs.cs_nffree, -frags, needswap); 355 fs->fs_cstotal.cs_nffree -= frags; 356 fs->fs_cs(fs, cg).cs_nffree -= frags; 357 fs->fs_fmod = 1; 358 ufs_add32(cgp->cg_frsum[allocsiz], -1, needswap); 359 if (frags != allocsiz) 360 ufs_add32(cgp->cg_frsum[allocsiz - frags], 1, needswap); 361 blkno = cg * fs->fs_fpg + bno; 362 bdwrite(bp); 363 return blkno; 364} 365 366/* 367 * Allocate a block in a cylinder group. 368 * 369 * This algorithm implements the following policy: 370 * 1) allocate the requested block. 371 * 2) allocate a rotationally optimal block in the same cylinder. 372 * 3) allocate the next available block on the block rotor for the 373 * specified cylinder group. 374 * Note that this routine only allocates fs_bsize blocks; these 375 * blocks may be fragmented by the routine that allocates them. 376 */ 377static daddr_t 378ffs_alloccgblk(struct inode *ip, struct buf *bp, daddr_t bpref) 379{ 380 struct cg *cgp; 381 daddr_t blkno; 382 int32_t bno; 383 struct fs *fs = ip->i_fs; 384 const int needswap = UFS_FSNEEDSWAP(fs); 385 u_int8_t *blksfree_swap; 386 387 cgp = (struct cg *)bp->b_data; 388 blksfree_swap = cg_blksfree_swap(cgp, needswap); 389 if (bpref == 0 || (uint32_t)dtog(fs, bpref) != ufs_rw32(cgp->cg_cgx, needswap)) { 390 bpref = ufs_rw32(cgp->cg_rotor, needswap); 391 } else { 392 bpref = blknum(fs, bpref); 393 bno = dtogd(fs, bpref); 394 /* 395 * if the requested block is available, use it 396 */ 397 if (ffs_isblock(fs, blksfree_swap, fragstoblks(fs, bno))) 398 goto gotit; 399 } 400 /* 401 * Take the next available one in this cylinder group. 402 */ 403 bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag); 404 if (bno < 0) 405 return (0); 406 cgp->cg_rotor = ufs_rw32(bno, needswap); 407gotit: 408 blkno = fragstoblks(fs, bno); 409 ffs_clrblock(fs, blksfree_swap, (long)blkno); 410 ffs_clusteracct(fs, cgp, blkno, -1); 411 ufs_add32(cgp->cg_cs.cs_nbfree, -1, needswap); 412 fs->fs_cstotal.cs_nbfree--; 413 fs->fs_cs(fs, ufs_rw32(cgp->cg_cgx, needswap)).cs_nbfree--; 414 fs->fs_fmod = 1; 415 blkno = ufs_rw32(cgp->cg_cgx, needswap) * fs->fs_fpg + bno; 416 return (blkno); 417} 418 419/* 420 * Free a block or fragment. 421 * 422 * The specified block or fragment is placed back in the 423 * free map. If a fragment is deallocated, a possible 424 * block reassembly is checked. 425 */ 426void 427ffs_blkfree(struct inode *ip, daddr_t bno, long size) 428{ 429 struct cg *cgp; 430 struct buf *bp; 431 int32_t fragno, cgbno; 432 int i, error, cg, blk, frags, bbase; 433 struct fs *fs = ip->i_fs; 434 const int needswap = UFS_FSNEEDSWAP(fs); 435 436 if (size > fs->fs_bsize || fragoff(fs, size) != 0 || 437 fragnum(fs, bno) + numfrags(fs, size) > fs->fs_frag) { 438 errx(1, "blkfree: bad size: bno %lld bsize %d size %ld", 439 (long long)bno, fs->fs_bsize, size); 440 } 441 cg = dtog(fs, bno); 442 if (bno >= fs->fs_size) { 443 warnx("bad block %lld, ino %ju", (long long)bno, 444 (uintmax_t)ip->i_number); 445 return; 446 } 447 error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)), 448 (int)fs->fs_cgsize, &bp); 449 if (error) { 450 brelse(bp); 451 return; 452 } 453 cgp = (struct cg *)bp->b_data; 454 if (!cg_chkmagic_swap(cgp, needswap)) { 455 brelse(bp); 456 return; 457 } 458 cgbno = dtogd(fs, bno); 459 if (size == fs->fs_bsize) { 460 fragno = fragstoblks(fs, cgbno); 461 if (!ffs_isfreeblock(fs, cg_blksfree_swap(cgp, needswap), fragno)) { 462 errx(1, "blkfree: freeing free block %lld", 463 (long long)bno); 464 } 465 ffs_setblock(fs, cg_blksfree_swap(cgp, needswap), fragno); 466 ffs_clusteracct(fs, cgp, fragno, 1); 467 ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); 468 fs->fs_cstotal.cs_nbfree++; 469 fs->fs_cs(fs, cg).cs_nbfree++; 470 } else { 471 bbase = cgbno - fragnum(fs, cgbno); 472 /* 473 * decrement the counts associated with the old frags 474 */ 475 blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bbase); 476 ffs_fragacct_swap(fs, blk, cgp->cg_frsum, -1, needswap); 477 /* 478 * deallocate the fragment 479 */ 480 frags = numfrags(fs, size); 481 for (i = 0; i < frags; i++) { 482 if (isset(cg_blksfree_swap(cgp, needswap), cgbno + i)) { 483 errx(1, "blkfree: freeing free frag: block %lld", 484 (long long)(cgbno + i)); 485 } 486 setbit(cg_blksfree_swap(cgp, needswap), cgbno + i); 487 } 488 ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); 489 fs->fs_cstotal.cs_nffree += i; 490 fs->fs_cs(fs, cg).cs_nffree += i; 491 /* 492 * add back in counts associated with the new frags 493 */ 494 blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bbase); 495 ffs_fragacct_swap(fs, blk, cgp->cg_frsum, 1, needswap); 496 /* 497 * if a complete block has been reassembled, account for it 498 */ 499 fragno = fragstoblks(fs, bbase); 500 if (ffs_isblock(fs, cg_blksfree_swap(cgp, needswap), fragno)) { 501 ufs_add32(cgp->cg_cs.cs_nffree, -fs->fs_frag, needswap); 502 fs->fs_cstotal.cs_nffree -= fs->fs_frag; 503 fs->fs_cs(fs, cg).cs_nffree -= fs->fs_frag; 504 ffs_clusteracct(fs, cgp, fragno, 1); 505 ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); 506 fs->fs_cstotal.cs_nbfree++; 507 fs->fs_cs(fs, cg).cs_nbfree++; 508 } 509 } 510 fs->fs_fmod = 1; 511 bdwrite(bp); 512} 513 514 515static int 516scanc(u_int size, const u_char *cp, const u_char table[], int mask) 517{ 518 const u_char *end = &cp[size]; 519 520 while (cp < end && (table[*cp] & mask) == 0) 521 cp++; 522 return (end - cp); 523} 524 525/* 526 * Find a block of the specified size in the specified cylinder group. 527 * 528 * It is a panic if a request is made to find a block if none are 529 * available. 530 */ 531static int32_t 532ffs_mapsearch(struct fs *fs, struct cg *cgp, daddr_t bpref, int allocsiz) 533{ 534 int32_t bno; 535 int start, len, loc, i; 536 int blk, field, subfield, pos; 537 int ostart, olen; 538 const int needswap = UFS_FSNEEDSWAP(fs); 539 540 /* 541 * find the fragment by searching through the free block 542 * map for an appropriate bit pattern 543 */ 544 if (bpref) 545 start = dtogd(fs, bpref) / NBBY; 546 else 547 start = ufs_rw32(cgp->cg_frotor, needswap) / NBBY; 548 len = howmany(fs->fs_fpg, NBBY) - start; 549 ostart = start; 550 olen = len; 551 loc = scanc((u_int)len, 552 (const u_char *)&cg_blksfree_swap(cgp, needswap)[start], 553 (const u_char *)fragtbl[fs->fs_frag], 554 (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); 555 if (loc == 0) { 556 len = start + 1; 557 start = 0; 558 loc = scanc((u_int)len, 559 (const u_char *)&cg_blksfree_swap(cgp, needswap)[0], 560 (const u_char *)fragtbl[fs->fs_frag], 561 (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); 562 if (loc == 0) { 563 errx(1, 564 "ffs_alloccg: map corrupted: start %d len %d offset %d %ld", 565 ostart, olen, 566 ufs_rw32(cgp->cg_freeoff, needswap), 567 (long)cg_blksfree_swap(cgp, needswap) - (long)cgp); 568 /* NOTREACHED */ 569 } 570 } 571 bno = (start + len - loc) * NBBY; 572 cgp->cg_frotor = ufs_rw32(bno, needswap); 573 /* 574 * found the byte in the map 575 * sift through the bits to find the selected frag 576 */ 577 for (i = bno + NBBY; bno < i; bno += fs->fs_frag) { 578 blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bno); 579 blk <<= 1; 580 field = around[allocsiz]; 581 subfield = inside[allocsiz]; 582 for (pos = 0; pos <= fs->fs_frag - allocsiz; pos++) { 583 if ((blk & field) == subfield) 584 return (bno + pos); 585 field <<= 1; 586 subfield <<= 1; 587 } 588 } 589 errx(1, "ffs_alloccg: block not in map: bno %lld", (long long)bno); 590 return (-1); 591} 592 593/* 594 * Update the cluster map because of an allocation or free. 595 * 596 * Cnt == 1 means free; cnt == -1 means allocating. 597 */ 598void 599ffs_clusteracct(struct fs *fs, struct cg *cgp, int32_t blkno, int cnt) 600{ 601 int32_t *sump; 602 int32_t *lp; 603 u_char *freemapp, *mapp; 604 int i, start, end, forw, back, map, bit; 605 const int needswap = UFS_FSNEEDSWAP(fs); 606 607 if (fs->fs_contigsumsize <= 0) 608 return; 609 freemapp = cg_clustersfree_swap(cgp, needswap); 610 sump = cg_clustersum_swap(cgp, needswap); 611 /* 612 * Allocate or clear the actual block. 613 */ 614 if (cnt > 0) 615 setbit(freemapp, blkno); 616 else 617 clrbit(freemapp, blkno); 618 /* 619 * Find the size of the cluster going forward. 620 */ 621 start = blkno + 1; 622 end = start + fs->fs_contigsumsize; 623 if ((unsigned)end >= ufs_rw32(cgp->cg_nclusterblks, needswap)) 624 end = ufs_rw32(cgp->cg_nclusterblks, needswap); 625 mapp = &freemapp[start / NBBY]; 626 map = *mapp++; 627 bit = 1 << (start % NBBY); 628 for (i = start; i < end; i++) { 629 if ((map & bit) == 0) 630 break; 631 if ((i & (NBBY - 1)) != (NBBY - 1)) { 632 bit <<= 1; 633 } else { 634 map = *mapp++; 635 bit = 1; 636 } 637 } 638 forw = i - start; 639 /* 640 * Find the size of the cluster going backward. 641 */ 642 start = blkno - 1; 643 end = start - fs->fs_contigsumsize; 644 if (end < 0) 645 end = -1; 646 mapp = &freemapp[start / NBBY]; 647 map = *mapp--; 648 bit = 1 << (start % NBBY); 649 for (i = start; i > end; i--) { 650 if ((map & bit) == 0) 651 break; 652 if ((i & (NBBY - 1)) != 0) { 653 bit >>= 1; 654 } else { 655 map = *mapp--; 656 bit = 1 << (NBBY - 1); 657 } 658 } 659 back = start - i; 660 /* 661 * Account for old cluster and the possibly new forward and 662 * back clusters. 663 */ 664 i = back + forw + 1; 665 if (i > fs->fs_contigsumsize) 666 i = fs->fs_contigsumsize; 667 ufs_add32(sump[i], cnt, needswap); 668 if (back > 0) 669 ufs_add32(sump[back], -cnt, needswap); 670 if (forw > 0) 671 ufs_add32(sump[forw], -cnt, needswap); 672 673 /* 674 * Update cluster summary information. 675 */ 676 lp = &sump[fs->fs_contigsumsize]; 677 for (i = fs->fs_contigsumsize; i > 0; i--) 678 if (ufs_rw32(*lp--, needswap) > 0) 679 break; 680 fs->fs_maxcluster[ufs_rw32(cgp->cg_cgx, needswap)] = i; 681} 682