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