1 /* $NetBSD: ffs_alloc.c,v 1.11 2003/01/24 21:55:32 fvdl Exp $ */ 2 /* From: NetBSD: ffs_alloc.c,v 1.50 2001/09/06 02:16:01 lukem Exp */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1989, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. 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 * @(#)ffs_alloc.c 8.19 (Berkeley) 7/13/95 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(__RCSID) && !defined(__lint) 41 __RCSID("$NetBSD: ffs_alloc.c,v 1.11 2003/01/24 21:55:32 fvdl Exp $"); 42 #endif /* !__lint */ 43 44 #include <sys/param.h> 45 #include <sys/time.h> 46 47 #include <errno.h> 48 49 #include "makefs.h" 50 51 #include <ufs/ufs/dinode.h> 52 #include <ufs/ufs/ufs_bswap.h> 53 #include <ufs/ffs/fs.h> 54 55 #include "ffs/buf.h" 56 #include "ffs/ufs_inode.h" 57 #include "ffs/ffs_extern.h" 58 59 60 static int scanc(u_int, const u_char *, const u_char *, int); 61 62 static daddr_t ffs_alloccg(struct inode *, int, daddr_t, int); 63 static daddr_t ffs_alloccgblk(struct inode *, struct buf *, daddr_t); 64 static daddr_t ffs_hashalloc(struct inode *, int, daddr_t, int, 65 daddr_t (*)(struct inode *, int, daddr_t, int)); 66 static daddr_t ffs_mapsearch(struct fs *, struct cg *, daddr_t, int); 67 68 /* in ffs_tables.c */ 69 extern const int inside[], around[]; 70 extern const u_char * const fragtbl[]; 71 72 /* 73 * Allocate a block in the file system. 74 * 75 * The size of the requested block is given, which must be some 76 * multiple of fs_fsize and <= fs_bsize. 77 * A preference may be optionally specified. If a preference is given 78 * the following hierarchy is used to allocate a block: 79 * 1) allocate the requested block. 80 * 2) allocate a rotationally optimal block in the same cylinder. 81 * 3) allocate a block in the same cylinder group. 82 * 4) quadradically rehash into other cylinder groups, until an 83 * available block is located. 84 * If no block preference is given the following hierarchy is used 85 * to allocate a block: 86 * 1) allocate a block in the cylinder group that contains the 87 * inode for the file. 88 * 2) quadradically rehash into other cylinder groups, until an 89 * available block is located. 90 */ 91 int 92 ffs_alloc(struct inode *ip, daddr_t lbn, daddr_t bpref, int size, 93 daddr_t *bnp) 94 { 95 struct fs *fs = ip->i_fs; 96 daddr_t bno; 97 int cg; 98 99 *bnp = 0; 100 if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0) { 101 errx(1, "ffs_alloc: bad size: bsize %d size %d", 102 fs->fs_bsize, size); 103 } 104 if (size == fs->fs_bsize && fs->fs_cstotal.cs_nbfree == 0) 105 goto nospace; 106 if (bpref >= fs->fs_size) 107 bpref = 0; 108 if (bpref == 0) 109 cg = ino_to_cg(fs, ip->i_number); 110 else 111 cg = dtog(fs, bpref); 112 bno = ffs_hashalloc(ip, cg, bpref, size, ffs_alloccg); 113 if (bno > 0) { 114 ip->i_ffs_blocks += size / DEV_BSIZE; 115 *bnp = bno; 116 return (0); 117 } 118 nospace: 119 return (ENOSPC); 120 } 121 122 /* 123 * Select the desired position for the next block in a file. The file is 124 * logically divided into sections. The first section is composed of the 125 * direct blocks. Each additional section contains fs_maxbpg blocks. 126 * 127 * If no blocks have been allocated in the first section, the policy is to 128 * request a block in the same cylinder group as the inode that describes 129 * the file. If no blocks have been allocated in any other section, the 130 * policy is to place the section in a cylinder group with a greater than 131 * average number of free blocks. An appropriate cylinder group is found 132 * by using a rotor that sweeps the cylinder groups. When a new group of 133 * blocks is needed, the sweep begins in the cylinder group following the 134 * cylinder group from which the previous allocation was made. The sweep 135 * continues until a cylinder group with greater than the average number 136 * of free blocks is found. If the allocation is for the first block in an 137 * indirect block, the information on the previous allocation is unavailable; 138 * here a best guess is made based upon the logical block number being 139 * allocated. 140 * 141 * If a section is already partially allocated, the policy is to 142 * contiguously allocate fs_maxcontig blocks. The end of one of these 143 * contiguous blocks and the beginning of the next is physically separated 144 * so that the disk head will be in transit between them for at least 145 * fs_rotdelay milliseconds. This is to allow time for the processor to 146 * schedule another I/O transfer. 147 */ 148 /* XXX ondisk32 */ 149 daddr_t 150 ffs_blkpref(struct inode *ip, daddr_t lbn, int indx, int32_t *bap) 151 { 152 struct fs *fs; 153 int cg; 154 int avgbfree, startcg; 155 daddr_t nextblk; 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 fs->fs_cgrotor = cg; 178 return (fs->fs_fpg * cg + fs->fs_frag); 179 } 180 for (cg = 0; cg <= startcg; cg++) 181 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) { 182 fs->fs_cgrotor = cg; 183 return (fs->fs_fpg * cg + fs->fs_frag); 184 } 185 return (0); 186 } 187 /* 188 * One or more previous blocks have been laid out. If less 189 * than fs_maxcontig previous blocks are contiguous, the 190 * next block is requested contiguously, otherwise it is 191 * requested rotationally delayed by fs_rotdelay milliseconds. 192 */ 193 /* XXX ondisk32 */ 194 nextblk = ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag; 195 if (indx < fs->fs_maxcontig || 196 ufs_rw32(bap[indx - fs->fs_maxcontig], UFS_FSNEEDSWAP(fs)) + 197 blkstofrags(fs, fs->fs_maxcontig) != nextblk) 198 return (nextblk); 199 if (fs->fs_rotdelay != 0) 200 /* 201 * Here we convert ms of delay to frags as: 202 * (frags) = (ms) * (rev/sec) * (sect/rev) / 203 * ((sect/frag) * (ms/sec)) 204 * then round up to the next block. 205 */ 206 nextblk += roundup(fs->fs_rotdelay * fs->fs_rps * fs->fs_nsect / 207 (NSPF(fs) * 1000), fs->fs_frag); 208 return (nextblk); 209 } 210 211 /* 212 * Implement the cylinder overflow algorithm. 213 * 214 * The policy implemented by this algorithm is: 215 * 1) allocate the block in its requested cylinder group. 216 * 2) quadradically rehash on the cylinder group number. 217 * 3) brute force search for a free block. 218 * 219 * `size': size for data blocks, mode for inodes 220 */ 221 /*VARARGS5*/ 222 static daddr_t 223 ffs_hashalloc(struct inode *ip, int cg, daddr_t pref, int size, 224 daddr_t (*allocator)(struct inode *, int, daddr_t, int)) 225 { 226 struct fs *fs; 227 daddr_t result; 228 int i, icg = cg; 229 230 fs = ip->i_fs; 231 /* 232 * 1: preferred cylinder group 233 */ 234 result = (*allocator)(ip, cg, pref, size); 235 if (result) 236 return (result); 237 /* 238 * 2: quadratic rehash 239 */ 240 for (i = 1; i < fs->fs_ncg; i *= 2) { 241 cg += i; 242 if (cg >= fs->fs_ncg) 243 cg -= fs->fs_ncg; 244 result = (*allocator)(ip, cg, 0, size); 245 if (result) 246 return (result); 247 } 248 /* 249 * 3: brute force search 250 * Note that we start at i == 2, since 0 was checked initially, 251 * and 1 is always checked in the quadratic rehash. 252 */ 253 cg = (icg + 2) % fs->fs_ncg; 254 for (i = 2; i < fs->fs_ncg; i++) { 255 result = (*allocator)(ip, cg, 0, size); 256 if (result) 257 return (result); 258 cg++; 259 if (cg == fs->fs_ncg) 260 cg = 0; 261 } 262 return (0); 263 } 264 265 /* 266 * Determine whether a block can be allocated. 267 * 268 * Check to see if a block of the appropriate size is available, 269 * and if it is, allocate it. 270 */ 271 static daddr_t 272 ffs_alloccg(struct inode *ip, int cg, daddr_t bpref, int size) 273 { 274 struct cg *cgp; 275 struct buf *bp; 276 daddr_t bno, blkno; 277 int error, frags, allocsiz, i; 278 struct fs *fs = ip->i_fs; 279 const int needswap = UFS_FSNEEDSWAP(fs); 280 281 if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize) 282 return (0); 283 error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)), 284 (int)fs->fs_cgsize, &bp); 285 if (error) { 286 brelse(bp); 287 return (0); 288 } 289 cgp = (struct cg *)bp->b_data; 290 if (!cg_chkmagic(cgp, needswap) || 291 (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize)) { 292 brelse(bp); 293 return (0); 294 } 295 if (size == fs->fs_bsize) { 296 bno = ffs_alloccgblk(ip, bp, bpref); 297 bdwrite(bp); 298 return (bno); 299 } 300 /* 301 * check to see if any fragments are already available 302 * allocsiz is the size which will be allocated, hacking 303 * it down to a smaller size if necessary 304 */ 305 frags = numfrags(fs, size); 306 for (allocsiz = frags; allocsiz < fs->fs_frag; allocsiz++) 307 if (cgp->cg_frsum[allocsiz] != 0) 308 break; 309 if (allocsiz == fs->fs_frag) { 310 /* 311 * no fragments were available, so a block will be 312 * allocated, and hacked up 313 */ 314 if (cgp->cg_cs.cs_nbfree == 0) { 315 brelse(bp); 316 return (0); 317 } 318 bno = ffs_alloccgblk(ip, bp, bpref); 319 bpref = dtogd(fs, bno); 320 for (i = frags; i < fs->fs_frag; i++) 321 setbit(cg_blksfree(cgp, needswap), bpref + i); 322 i = fs->fs_frag - frags; 323 ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); 324 fs->fs_cstotal.cs_nffree += i; 325 fs->fs_cs(fs, cg).cs_nffree += i; 326 fs->fs_fmod = 1; 327 ufs_add32(cgp->cg_frsum[i], 1, needswap); 328 bdwrite(bp); 329 return (bno); 330 } 331 bno = ffs_mapsearch(fs, cgp, bpref, allocsiz); 332 for (i = 0; i < frags; i++) 333 clrbit(cg_blksfree(cgp, needswap), bno + i); 334 ufs_add32(cgp->cg_cs.cs_nffree, -frags, needswap); 335 fs->fs_cstotal.cs_nffree -= frags; 336 fs->fs_cs(fs, cg).cs_nffree -= frags; 337 fs->fs_fmod = 1; 338 ufs_add32(cgp->cg_frsum[allocsiz], -1, needswap); 339 if (frags != allocsiz) 340 ufs_add32(cgp->cg_frsum[allocsiz - frags], 1, needswap); 341 blkno = cg * fs->fs_fpg + bno; 342 bdwrite(bp); 343 return blkno; 344 } 345 346 /* 347 * Allocate a block in a cylinder group. 348 * 349 * This algorithm implements the following policy: 350 * 1) allocate the requested block. 351 * 2) allocate a rotationally optimal block in the same cylinder. 352 * 3) allocate the next available block on the block rotor for the 353 * specified cylinder group. 354 * Note that this routine only allocates fs_bsize blocks; these 355 * blocks may be fragmented by the routine that allocates them. 356 */ 357 static daddr_t 358 ffs_alloccgblk(struct inode *ip, struct buf *bp, daddr_t bpref) 359 { 360 struct cg *cgp; 361 daddr_t bno, blkno; 362 int cylno, pos, delta; 363 short *cylbp; 364 int i; 365 struct fs *fs = ip->i_fs; 366 const int needswap = UFS_FSNEEDSWAP(fs); 367 368 cgp = (struct cg *)bp->b_data; 369 /* XXX ondisk32 */ 370 if (bpref == 0 || dtog(fs, bpref) != ufs_rw32(cgp->cg_cgx, needswap)) { 371 bpref = ufs_rw32(cgp->cg_rotor, needswap); 372 goto norot; 373 } 374 bpref = blknum(fs, bpref); 375 bpref = dtogd(fs, bpref); 376 /* 377 * if the requested block is available, use it 378 */ 379 if (ffs_isblock(fs, cg_blksfree(cgp, needswap), 380 fragstoblks(fs, bpref))) { 381 bno = bpref; 382 goto gotit; 383 } 384 if (fs->fs_nrpos <= 1 || fs->fs_cpc == 0) { 385 /* 386 * Block layout information is not available. 387 * Leaving bpref unchanged means we take the 388 * next available free block following the one 389 * we just allocated. Hopefully this will at 390 * least hit a track cache on drives of unknown 391 * geometry (e.g. SCSI). 392 */ 393 goto norot; 394 } 395 /* 396 * check for a block available on the same cylinder 397 */ 398 cylno = cbtocylno(fs, bpref); 399 if (cg_blktot(cgp, needswap)[cylno] == 0) 400 goto norot; 401 /* 402 * check the summary information to see if a block is 403 * available in the requested cylinder starting at the 404 * requested rotational position and proceeding around. 405 */ 406 cylbp = cg_blks(fs, cgp, cylno, needswap); 407 pos = cbtorpos(fs, bpref); 408 for (i = pos; i < fs->fs_nrpos; i++) 409 if (ufs_rw16(cylbp[i], needswap) > 0) 410 break; 411 if (i == fs->fs_nrpos) 412 for (i = 0; i < pos; i++) 413 if (ufs_rw16(cylbp[i], needswap) > 0) 414 break; 415 if (ufs_rw16(cylbp[i], needswap) > 0) { 416 /* 417 * found a rotational position, now find the actual 418 * block. A panic if none is actually there. 419 */ 420 pos = cylno % fs->fs_cpc; 421 bno = (cylno - pos) * fs->fs_spc / NSPB(fs); 422 if (fs_postbl(fs, pos)[i] == -1) { 423 errx(1, 424 "ffs_alloccgblk: cyl groups corrupted: pos %d i %d", 425 pos, i); 426 } 427 for (i = fs_postbl(fs, pos)[i];; ) { 428 if (ffs_isblock(fs, cg_blksfree(cgp, needswap), bno + i)) { 429 bno = blkstofrags(fs, (bno + i)); 430 goto gotit; 431 } 432 delta = fs_rotbl(fs)[i]; 433 if (delta <= 0 || 434 delta + i > fragstoblks(fs, fs->fs_fpg)) 435 break; 436 i += delta; 437 } 438 errx(1, "ffs_alloccgblk: can't find blk in cyl: pos %d i %d", 439 pos, i); 440 } 441 norot: 442 /* 443 * no blocks in the requested cylinder, so take next 444 * available one in this cylinder group. 445 */ 446 bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag); 447 if (bno < 0) 448 return (0); 449 /* XXX ondisk32 */ 450 cgp->cg_rotor = ufs_rw64(bno, needswap); 451 gotit: 452 blkno = fragstoblks(fs, bno); 453 ffs_clrblock(fs, cg_blksfree(cgp, needswap), (long)blkno); 454 ffs_clusteracct(fs, cgp, blkno, -1); 455 ufs_add32(cgp->cg_cs.cs_nbfree, -1, needswap); 456 fs->fs_cstotal.cs_nbfree--; 457 fs->fs_cs(fs, ufs_rw32(cgp->cg_cgx, needswap)).cs_nbfree--; 458 cylno = cbtocylno(fs, bno); 459 ufs_add16(cg_blks(fs, cgp, cylno, needswap)[cbtorpos(fs, bno)], -1, 460 needswap); 461 ufs_add32(cg_blktot(cgp, needswap)[cylno], -1, needswap); 462 fs->fs_fmod = 1; 463 /* XXX ondisk32 */ 464 blkno = ufs_rw32(cgp->cg_cgx, needswap) * fs->fs_fpg + bno; 465 return (blkno); 466 } 467 468 /* 469 * Free a block or fragment. 470 * 471 * The specified block or fragment is placed back in the 472 * free map. If a fragment is deallocated, a possible 473 * block reassembly is checked. 474 */ 475 void 476 ffs_blkfree(struct inode *ip, daddr_t bno, long size) 477 { 478 struct cg *cgp; 479 struct buf *bp; 480 daddr_t blkno; 481 int i, error, cg, blk, frags, bbase; 482 struct fs *fs = ip->i_fs; 483 const int needswap = UFS_FSNEEDSWAP(fs); 484 485 if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0 || 486 fragnum(fs, bno) + numfrags(fs, size) > fs->fs_frag) { 487 errx(1, "blkfree: bad size: bno %lld bsize %d size %ld", 488 (long long)bno, fs->fs_bsize, size); 489 } 490 cg = dtog(fs, bno); 491 if ((u_int)bno >= fs->fs_size) { 492 warnx("bad block %lld, ino %d", (long long)bno, ip->i_number); 493 return; 494 } 495 error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)), 496 (int)fs->fs_cgsize, &bp); 497 if (error) { 498 brelse(bp); 499 return; 500 } 501 cgp = (struct cg *)bp->b_data; 502 if (!cg_chkmagic(cgp, needswap)) { 503 brelse(bp); 504 return; 505 } 506 bno = dtogd(fs, bno); 507 if (size == fs->fs_bsize) { 508 blkno = fragstoblks(fs, bno); 509 if (!ffs_isfreeblock(fs, cg_blksfree(cgp, needswap), blkno)) { 510 errx(1, "blkfree: freeing free block %lld", 511 (long long)bno); 512 } 513 ffs_setblock(fs, cg_blksfree(cgp, needswap), blkno); 514 ffs_clusteracct(fs, cgp, blkno, 1); 515 ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); 516 fs->fs_cstotal.cs_nbfree++; 517 fs->fs_cs(fs, cg).cs_nbfree++; 518 i = cbtocylno(fs, bno); 519 ufs_add16(cg_blks(fs, cgp, i, needswap)[cbtorpos(fs, bno)], 1, 520 needswap); 521 ufs_add32(cg_blktot(cgp, needswap)[i], 1, needswap); 522 } else { 523 bbase = bno - fragnum(fs, bno); 524 /* 525 * decrement the counts associated with the old frags 526 */ 527 blk = blkmap(fs, cg_blksfree(cgp, needswap), bbase); 528 ffs_fragacct(fs, blk, cgp->cg_frsum, -1, needswap); 529 /* 530 * deallocate the fragment 531 */ 532 frags = numfrags(fs, size); 533 for (i = 0; i < frags; i++) { 534 if (isset(cg_blksfree(cgp, needswap), bno + i)) { 535 errx(1, "blkfree: freeing free frag: block %lld", 536 (long long)(bno + i)); 537 } 538 setbit(cg_blksfree(cgp, needswap), bno + i); 539 } 540 ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); 541 fs->fs_cstotal.cs_nffree += i; 542 fs->fs_cs(fs, cg).cs_nffree += i; 543 /* 544 * add back in counts associated with the new frags 545 */ 546 blk = blkmap(fs, cg_blksfree(cgp, needswap), bbase); 547 ffs_fragacct(fs, blk, cgp->cg_frsum, 1, needswap); 548 /* 549 * if a complete block has been reassembled, account for it 550 */ 551 blkno = fragstoblks(fs, bbase); 552 if (ffs_isblock(fs, cg_blksfree(cgp, needswap), blkno)) { 553 ufs_add32(cgp->cg_cs.cs_nffree, -fs->fs_frag, needswap); 554 fs->fs_cstotal.cs_nffree -= fs->fs_frag; 555 fs->fs_cs(fs, cg).cs_nffree -= fs->fs_frag; 556 ffs_clusteracct(fs, cgp, blkno, 1); 557 ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); 558 fs->fs_cstotal.cs_nbfree++; 559 fs->fs_cs(fs, cg).cs_nbfree++; 560 i = cbtocylno(fs, bbase); 561 ufs_add16(cg_blks(fs, cgp, i, needswap)[cbtorpos(fs, 562 bbase)], 1, 563 needswap); 564 ufs_add32(cg_blktot(cgp, needswap)[i], 1, needswap); 565 } 566 } 567 fs->fs_fmod = 1; 568 bdwrite(bp); 569 } 570 571 572 static int 573 scanc(u_int size, const u_char *cp, const u_char table[], int mask) 574 { 575 const u_char *end = &cp[size]; 576 577 while (cp < end && (table[*cp] & mask) == 0) 578 cp++; 579 return (end - cp); 580 } 581 582 /* 583 * Find a block of the specified size in the specified cylinder group. 584 * 585 * It is a panic if a request is made to find a block if none are 586 * available. 587 */ 588 static daddr_t 589 ffs_mapsearch(struct fs *fs, struct cg *cgp, daddr_t bpref, int allocsiz) 590 { 591 daddr_t bno; 592 int start, len, loc, i; 593 int blk, field, subfield, pos; 594 int ostart, olen; 595 const int needswap = UFS_FSNEEDSWAP(fs); 596 597 /* 598 * find the fragment by searching through the free block 599 * map for an appropriate bit pattern 600 */ 601 if (bpref) 602 start = dtogd(fs, bpref) / NBBY; 603 else 604 start = ufs_rw32(cgp->cg_frotor, needswap) / NBBY; 605 len = howmany(fs->fs_fpg, NBBY) - start; 606 ostart = start; 607 olen = len; 608 loc = scanc((u_int)len, 609 (const u_char *)&cg_blksfree(cgp, needswap)[start], 610 (const u_char *)fragtbl[fs->fs_frag], 611 (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); 612 if (loc == 0) { 613 len = start + 1; 614 start = 0; 615 loc = scanc((u_int)len, 616 (const u_char *)&cg_blksfree(cgp, needswap)[0], 617 (const u_char *)fragtbl[fs->fs_frag], 618 (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); 619 if (loc == 0) { 620 errx(1, 621 "ffs_alloccg: map corrupted: start %d len %d offset %d %ld", 622 ostart, olen, 623 ufs_rw32(cgp->cg_freeoff, needswap), 624 (long)cg_blksfree(cgp, needswap) - (long)cgp); 625 /* NOTREACHED */ 626 } 627 } 628 bno = (start + len - loc) * NBBY; 629 cgp->cg_frotor = ufs_rw32(bno, needswap); 630 /* 631 * found the byte in the map 632 * sift through the bits to find the selected frag 633 */ 634 for (i = bno + NBBY; bno < i; bno += fs->fs_frag) { 635 blk = blkmap(fs, cg_blksfree(cgp, needswap), bno); 636 blk <<= 1; 637 field = around[allocsiz]; 638 subfield = inside[allocsiz]; 639 for (pos = 0; pos <= fs->fs_frag - allocsiz; pos++) { 640 if ((blk & field) == subfield) 641 return (bno + pos); 642 field <<= 1; 643 subfield <<= 1; 644 } 645 } 646 errx(1, "ffs_alloccg: block not in map: bno %lld", (long long)bno); 647 return (-1); 648 } 649 650 /* 651 * Update the cluster map because of an allocation or free. 652 * 653 * Cnt == 1 means free; cnt == -1 means allocating. 654 */ 655 void 656 ffs_clusteracct(struct fs *fs, struct cg *cgp, daddr_t blkno, int cnt) 657 { 658 int32_t *sump; 659 int32_t *lp; 660 u_char *freemapp, *mapp; 661 int i, start, end, forw, back, map, bit; 662 const int needswap = UFS_FSNEEDSWAP(fs); 663 664 if (fs->fs_contigsumsize <= 0) 665 return; 666 freemapp = cg_clustersfree(cgp, needswap); 667 sump = cg_clustersum(cgp, needswap); 668 /* 669 * Allocate or clear the actual block. 670 */ 671 if (cnt > 0) 672 setbit(freemapp, blkno); 673 else 674 clrbit(freemapp, blkno); 675 /* 676 * Find the size of the cluster going forward. 677 */ 678 start = blkno + 1; 679 end = start + fs->fs_contigsumsize; 680 if (end >= ufs_rw32(cgp->cg_nclusterblks, needswap)) 681 end = ufs_rw32(cgp->cg_nclusterblks, needswap); 682 mapp = &freemapp[start / NBBY]; 683 map = *mapp++; 684 bit = 1 << (start % NBBY); 685 for (i = start; i < end; i++) { 686 if ((map & bit) == 0) 687 break; 688 if ((i & (NBBY - 1)) != (NBBY - 1)) { 689 bit <<= 1; 690 } else { 691 map = *mapp++; 692 bit = 1; 693 } 694 } 695 forw = i - start; 696 /* 697 * Find the size of the cluster going backward. 698 */ 699 start = blkno - 1; 700 end = start - fs->fs_contigsumsize; 701 if (end < 0) 702 end = -1; 703 mapp = &freemapp[start / NBBY]; 704 map = *mapp--; 705 bit = 1 << (start % NBBY); 706 for (i = start; i > end; i--) { 707 if ((map & bit) == 0) 708 break; 709 if ((i & (NBBY - 1)) != 0) { 710 bit >>= 1; 711 } else { 712 map = *mapp--; 713 bit = 1 << (NBBY - 1); 714 } 715 } 716 back = start - i; 717 /* 718 * Account for old cluster and the possibly new forward and 719 * back clusters. 720 */ 721 i = back + forw + 1; 722 if (i > fs->fs_contigsumsize) 723 i = fs->fs_contigsumsize; 724 ufs_add32(sump[i], cnt, needswap); 725 if (back > 0) 726 ufs_add32(sump[back], -cnt, needswap); 727 if (forw > 0) 728 ufs_add32(sump[forw], -cnt, needswap); 729 730 /* 731 * Update cluster summary information. 732 */ 733 lp = &sump[fs->fs_contigsumsize]; 734 for (i = fs->fs_contigsumsize; i > 0; i--) 735 if (ufs_rw32(*lp--, needswap) > 0) 736 break; 737 fs->fs_maxcluster[ufs_rw32(cgp->cg_cgx, needswap)] = i; 738 } 739