1 /* $NetBSD: ffs_alloc.c,v 1.7 2002/01/08 06:00:14 lukem 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 #ifndef __lint 41 __RCSID("$NetBSD: ffs_alloc.c,v 1.7 2002/01/08 06:00:14 lukem Exp $"); 42 #endif /* !__lint */ 43 44 #include <sys/param.h> 45 #include <sys/time.h> 46 47 #include <err.h> 48 #include <errno.h> 49 50 #include "makefs.h" 51 52 #include <ufs/ufs/dinode.h> 53 #include <ufs/ufs/ufs_bswap.h> 54 #include <ufs/ffs/fs.h> 55 56 #include "ffs/buf.h" 57 #include "ffs/ufs_inode.h" 58 #include "ffs/ffs_extern.h" 59 60 61 static int scanc(u_int, const u_char *, const u_char *, int); 62 63 static ufs_daddr_t ffs_alloccg(struct inode *, int, ufs_daddr_t, int); 64 static ufs_daddr_t ffs_alloccgblk(struct inode *, struct buf *, ufs_daddr_t); 65 static u_long ffs_hashalloc(struct inode *, int, long, int, 66 ufs_daddr_t (*)(struct inode *, int, ufs_daddr_t, int)); 67 static ufs_daddr_t ffs_mapsearch(struct fs *, struct cg *, ufs_daddr_t, int); 68 69 /* in ffs_tables.c */ 70 extern const int inside[], around[]; 71 extern const u_char * const fragtbl[]; 72 73 /* 74 * Allocate a block in the file system. 75 * 76 * The size of the requested block is given, which must be some 77 * multiple of fs_fsize and <= fs_bsize. 78 * A preference may be optionally specified. If a preference is given 79 * the following hierarchy is used to allocate a block: 80 * 1) allocate the requested block. 81 * 2) allocate a rotationally optimal block in the same cylinder. 82 * 3) allocate a block in the same cylinder group. 83 * 4) quadradically rehash into other cylinder groups, until an 84 * available block is located. 85 * If no block preference is given the following hierarchy is used 86 * to allocate a block: 87 * 1) allocate a block in the cylinder group that contains the 88 * inode for the file. 89 * 2) quadradically rehash into other cylinder groups, until an 90 * available block is located. 91 */ 92 int 93 ffs_alloc(struct inode *ip, ufs_daddr_t lbn, ufs_daddr_t bpref, int size, 94 ufs_daddr_t *bnp) 95 { 96 struct fs *fs = ip->i_fs; 97 ufs_daddr_t bno; 98 int cg; 99 100 *bnp = 0; 101 if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0) { 102 errx(1, "ffs_alloc: bad size: bsize %d size %d", 103 fs->fs_bsize, size); 104 } 105 if (size == fs->fs_bsize && fs->fs_cstotal.cs_nbfree == 0) 106 goto nospace; 107 if (bpref >= fs->fs_size) 108 bpref = 0; 109 if (bpref == 0) 110 cg = ino_to_cg(fs, ip->i_number); 111 else 112 cg = dtog(fs, bpref); 113 bno = (ufs_daddr_t)ffs_hashalloc(ip, cg, (long)bpref, size, 114 ffs_alloccg); 115 if (bno > 0) { 116 ip->i_ffs_blocks += btodb(size); 117 *bnp = bno; 118 return (0); 119 } 120 nospace: 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 ufs_daddr_t 151 ffs_blkpref(struct inode *ip, ufs_daddr_t lbn, int indx, ufs_daddr_t *bap) 152 { 153 struct fs *fs; 154 int cg; 155 int avgbfree, startcg; 156 ufs_daddr_t nextblk; 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 fs->fs_cgrotor = cg; 179 return (fs->fs_fpg * cg + fs->fs_frag); 180 } 181 for (cg = 0; cg <= startcg; cg++) 182 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) { 183 fs->fs_cgrotor = cg; 184 return (fs->fs_fpg * cg + fs->fs_frag); 185 } 186 return (0); 187 } 188 /* 189 * One or more previous blocks have been laid out. If less 190 * than fs_maxcontig previous blocks are contiguous, the 191 * next block is requested contiguously, otherwise it is 192 * requested rotationally delayed by fs_rotdelay milliseconds. 193 */ 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 u_long 223 ffs_hashalloc(struct inode *ip, int cg, long pref, int size, 224 ufs_daddr_t (*allocator)(struct inode *, int, ufs_daddr_t, int)) 225 { 226 struct fs *fs; 227 long 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 ufs_daddr_t 272 ffs_alloccg(struct inode *ip, int cg, ufs_daddr_t bpref, int size) 273 { 274 struct cg *cgp; 275 struct buf *bp; 276 ufs_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 ufs_daddr_t 358 ffs_alloccgblk(struct inode *ip, struct buf *bp, ufs_daddr_t bpref) 359 { 360 struct cg *cgp; 361 ufs_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 if (bpref == 0 || dtog(fs, bpref) != ufs_rw32(cgp->cg_cgx, needswap)) { 370 bpref = ufs_rw32(cgp->cg_rotor, needswap); 371 goto norot; 372 } 373 bpref = blknum(fs, bpref); 374 bpref = dtogd(fs, bpref); 375 /* 376 * if the requested block is available, use it 377 */ 378 if (ffs_isblock(fs, cg_blksfree(cgp, needswap), 379 fragstoblks(fs, bpref))) { 380 bno = bpref; 381 goto gotit; 382 } 383 if (fs->fs_nrpos <= 1 || fs->fs_cpc == 0) { 384 /* 385 * Block layout information is not available. 386 * Leaving bpref unchanged means we take the 387 * next available free block following the one 388 * we just allocated. Hopefully this will at 389 * least hit a track cache on drives of unknown 390 * geometry (e.g. SCSI). 391 */ 392 goto norot; 393 } 394 /* 395 * check for a block available on the same cylinder 396 */ 397 cylno = cbtocylno(fs, bpref); 398 if (cg_blktot(cgp, needswap)[cylno] == 0) 399 goto norot; 400 /* 401 * check the summary information to see if a block is 402 * available in the requested cylinder starting at the 403 * requested rotational position and proceeding around. 404 */ 405 cylbp = cg_blks(fs, cgp, cylno, needswap); 406 pos = cbtorpos(fs, bpref); 407 for (i = pos; i < fs->fs_nrpos; i++) 408 if (ufs_rw16(cylbp[i], needswap) > 0) 409 break; 410 if (i == fs->fs_nrpos) 411 for (i = 0; i < pos; i++) 412 if (ufs_rw16(cylbp[i], needswap) > 0) 413 break; 414 if (ufs_rw16(cylbp[i], needswap) > 0) { 415 /* 416 * found a rotational position, now find the actual 417 * block. A panic if none is actually there. 418 */ 419 pos = cylno % fs->fs_cpc; 420 bno = (cylno - pos) * fs->fs_spc / NSPB(fs); 421 if (fs_postbl(fs, pos)[i] == -1) { 422 errx(1, 423 "ffs_alloccgblk: cyl groups corrupted: pos %d i %d", 424 pos, i); 425 } 426 for (i = fs_postbl(fs, pos)[i];; ) { 427 if (ffs_isblock(fs, cg_blksfree(cgp, needswap), bno + i)) { 428 bno = blkstofrags(fs, (bno + i)); 429 goto gotit; 430 } 431 delta = fs_rotbl(fs)[i]; 432 if (delta <= 0 || 433 delta + i > fragstoblks(fs, fs->fs_fpg)) 434 break; 435 i += delta; 436 } 437 errx(1, "ffs_alloccgblk: can't find blk in cyl: pos %d i %d", 438 pos, i); 439 } 440 norot: 441 /* 442 * no blocks in the requested cylinder, so take next 443 * available one in this cylinder group. 444 */ 445 bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag); 446 if (bno < 0) 447 return (0); 448 cgp->cg_rotor = ufs_rw32(bno, needswap); 449 gotit: 450 blkno = fragstoblks(fs, bno); 451 ffs_clrblock(fs, cg_blksfree(cgp, needswap), (long)blkno); 452 ffs_clusteracct(fs, cgp, blkno, -1); 453 ufs_add32(cgp->cg_cs.cs_nbfree, -1, needswap); 454 fs->fs_cstotal.cs_nbfree--; 455 fs->fs_cs(fs, ufs_rw32(cgp->cg_cgx, needswap)).cs_nbfree--; 456 cylno = cbtocylno(fs, bno); 457 ufs_add16(cg_blks(fs, cgp, cylno, needswap)[cbtorpos(fs, bno)], -1, 458 needswap); 459 ufs_add32(cg_blktot(cgp, needswap)[cylno], -1, needswap); 460 fs->fs_fmod = 1; 461 blkno = ufs_rw32(cgp->cg_cgx, needswap) * fs->fs_fpg + bno; 462 return (blkno); 463 } 464 465 /* 466 * Free a block or fragment. 467 * 468 * The specified block or fragment is placed back in the 469 * free map. If a fragment is deallocated, a possible 470 * block reassembly is checked. 471 */ 472 void 473 ffs_blkfree(struct inode *ip, ufs_daddr_t bno, long size) 474 { 475 struct cg *cgp; 476 struct buf *bp; 477 ufs_daddr_t blkno; 478 int i, error, cg, blk, frags, bbase; 479 struct fs *fs = ip->i_fs; 480 const int needswap = UFS_FSNEEDSWAP(fs); 481 482 if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0 || 483 fragnum(fs, bno) + numfrags(fs, size) > fs->fs_frag) { 484 errx(1, "blkfree: bad size: bno %u bsize %d size %ld", 485 bno, fs->fs_bsize, size); 486 } 487 cg = dtog(fs, bno); 488 if ((u_int)bno >= fs->fs_size) { 489 warnx("bad block %d, ino %d\n", bno, ip->i_number); 490 return; 491 } 492 error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)), 493 (int)fs->fs_cgsize, &bp); 494 if (error) { 495 brelse(bp); 496 return; 497 } 498 cgp = (struct cg *)bp->b_data; 499 if (!cg_chkmagic(cgp, needswap)) { 500 brelse(bp); 501 return; 502 } 503 bno = dtogd(fs, bno); 504 if (size == fs->fs_bsize) { 505 blkno = fragstoblks(fs, bno); 506 if (!ffs_isfreeblock(fs, cg_blksfree(cgp, needswap), blkno)) { 507 errx(1, "blkfree: freeing free block %d", bno); 508 } 509 ffs_setblock(fs, cg_blksfree(cgp, needswap), blkno); 510 ffs_clusteracct(fs, cgp, blkno, 1); 511 ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); 512 fs->fs_cstotal.cs_nbfree++; 513 fs->fs_cs(fs, cg).cs_nbfree++; 514 i = cbtocylno(fs, bno); 515 ufs_add16(cg_blks(fs, cgp, i, needswap)[cbtorpos(fs, bno)], 1, 516 needswap); 517 ufs_add32(cg_blktot(cgp, needswap)[i], 1, needswap); 518 } else { 519 bbase = bno - fragnum(fs, bno); 520 /* 521 * decrement the counts associated with the old frags 522 */ 523 blk = blkmap(fs, cg_blksfree(cgp, needswap), bbase); 524 ffs_fragacct(fs, blk, cgp->cg_frsum, -1, needswap); 525 /* 526 * deallocate the fragment 527 */ 528 frags = numfrags(fs, size); 529 for (i = 0; i < frags; i++) { 530 if (isset(cg_blksfree(cgp, needswap), bno + i)) { 531 errx(1, "blkfree: freeing free frag: block %d", 532 bno + i); 533 } 534 setbit(cg_blksfree(cgp, needswap), bno + i); 535 } 536 ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); 537 fs->fs_cstotal.cs_nffree += i; 538 fs->fs_cs(fs, cg).cs_nffree += i; 539 /* 540 * add back in counts associated with the new frags 541 */ 542 blk = blkmap(fs, cg_blksfree(cgp, needswap), bbase); 543 ffs_fragacct(fs, blk, cgp->cg_frsum, 1, needswap); 544 /* 545 * if a complete block has been reassembled, account for it 546 */ 547 blkno = fragstoblks(fs, bbase); 548 if (ffs_isblock(fs, cg_blksfree(cgp, needswap), blkno)) { 549 ufs_add32(cgp->cg_cs.cs_nffree, -fs->fs_frag, needswap); 550 fs->fs_cstotal.cs_nffree -= fs->fs_frag; 551 fs->fs_cs(fs, cg).cs_nffree -= fs->fs_frag; 552 ffs_clusteracct(fs, cgp, blkno, 1); 553 ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); 554 fs->fs_cstotal.cs_nbfree++; 555 fs->fs_cs(fs, cg).cs_nbfree++; 556 i = cbtocylno(fs, bbase); 557 ufs_add16(cg_blks(fs, cgp, i, needswap)[cbtorpos(fs, 558 bbase)], 1, 559 needswap); 560 ufs_add32(cg_blktot(cgp, needswap)[i], 1, needswap); 561 } 562 } 563 fs->fs_fmod = 1; 564 bdwrite(bp); 565 } 566 567 568 static int 569 scanc(u_int size, const u_char *cp, const u_char table[], int mask) 570 { 571 const u_char *end = &cp[size]; 572 573 while (cp < end && (table[*cp] & mask) == 0) 574 cp++; 575 return (end - cp); 576 } 577 578 /* 579 * Find a block of the specified size in the specified cylinder group. 580 * 581 * It is a panic if a request is made to find a block if none are 582 * available. 583 */ 584 static ufs_daddr_t 585 ffs_mapsearch(struct fs *fs, struct cg *cgp, ufs_daddr_t bpref, int allocsiz) 586 { 587 ufs_daddr_t bno; 588 int start, len, loc, i; 589 int blk, field, subfield, pos; 590 int ostart, olen; 591 const int needswap = UFS_FSNEEDSWAP(fs); 592 593 /* 594 * find the fragment by searching through the free block 595 * map for an appropriate bit pattern 596 */ 597 if (bpref) 598 start = dtogd(fs, bpref) / NBBY; 599 else 600 start = ufs_rw32(cgp->cg_frotor, needswap) / NBBY; 601 len = howmany(fs->fs_fpg, NBBY) - start; 602 ostart = start; 603 olen = len; 604 loc = scanc((u_int)len, 605 (const u_char *)&cg_blksfree(cgp, needswap)[start], 606 (const u_char *)fragtbl[fs->fs_frag], 607 (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); 608 if (loc == 0) { 609 len = start + 1; 610 start = 0; 611 loc = scanc((u_int)len, 612 (const u_char *)&cg_blksfree(cgp, needswap)[0], 613 (const u_char *)fragtbl[fs->fs_frag], 614 (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); 615 if (loc == 0) { 616 errx(1, 617 "ffs_alloccg: map corrupted: start %d len %d offset %d %ld", 618 ostart, olen, 619 ufs_rw32(cgp->cg_freeoff, needswap), 620 (long)cg_blksfree(cgp, needswap) - (long)cgp); 621 /* NOTREACHED */ 622 } 623 } 624 bno = (start + len - loc) * NBBY; 625 cgp->cg_frotor = ufs_rw32(bno, needswap); 626 /* 627 * found the byte in the map 628 * sift through the bits to find the selected frag 629 */ 630 for (i = bno + NBBY; bno < i; bno += fs->fs_frag) { 631 blk = blkmap(fs, cg_blksfree(cgp, needswap), bno); 632 blk <<= 1; 633 field = around[allocsiz]; 634 subfield = inside[allocsiz]; 635 for (pos = 0; pos <= fs->fs_frag - allocsiz; pos++) { 636 if ((blk & field) == subfield) 637 return (bno + pos); 638 field <<= 1; 639 subfield <<= 1; 640 } 641 } 642 errx(1, "ffs_alloccg: block not in map: bno %d", bno); 643 return (-1); 644 } 645 646 /* 647 * Update the cluster map because of an allocation or free. 648 * 649 * Cnt == 1 means free; cnt == -1 means allocating. 650 */ 651 void 652 ffs_clusteracct(struct fs *fs, struct cg *cgp, ufs_daddr_t blkno, int cnt) 653 { 654 int32_t *sump; 655 int32_t *lp; 656 u_char *freemapp, *mapp; 657 int i, start, end, forw, back, map, bit; 658 const int needswap = UFS_FSNEEDSWAP(fs); 659 660 if (fs->fs_contigsumsize <= 0) 661 return; 662 freemapp = cg_clustersfree(cgp, needswap); 663 sump = cg_clustersum(cgp, needswap); 664 /* 665 * Allocate or clear the actual block. 666 */ 667 if (cnt > 0) 668 setbit(freemapp, blkno); 669 else 670 clrbit(freemapp, blkno); 671 /* 672 * Find the size of the cluster going forward. 673 */ 674 start = blkno + 1; 675 end = start + fs->fs_contigsumsize; 676 if (end >= ufs_rw32(cgp->cg_nclusterblks, needswap)) 677 end = ufs_rw32(cgp->cg_nclusterblks, needswap); 678 mapp = &freemapp[start / NBBY]; 679 map = *mapp++; 680 bit = 1 << (start % NBBY); 681 for (i = start; i < end; i++) { 682 if ((map & bit) == 0) 683 break; 684 if ((i & (NBBY - 1)) != (NBBY - 1)) { 685 bit <<= 1; 686 } else { 687 map = *mapp++; 688 bit = 1; 689 } 690 } 691 forw = i - start; 692 /* 693 * Find the size of the cluster going backward. 694 */ 695 start = blkno - 1; 696 end = start - fs->fs_contigsumsize; 697 if (end < 0) 698 end = -1; 699 mapp = &freemapp[start / NBBY]; 700 map = *mapp--; 701 bit = 1 << (start % NBBY); 702 for (i = start; i > end; i--) { 703 if ((map & bit) == 0) 704 break; 705 if ((i & (NBBY - 1)) != 0) { 706 bit >>= 1; 707 } else { 708 map = *mapp--; 709 bit = 1 << (NBBY - 1); 710 } 711 } 712 back = start - i; 713 /* 714 * Account for old cluster and the possibly new forward and 715 * back clusters. 716 */ 717 i = back + forw + 1; 718 if (i > fs->fs_contigsumsize) 719 i = fs->fs_contigsumsize; 720 ufs_add32(sump[i], cnt, needswap); 721 if (back > 0) 722 ufs_add32(sump[back], -cnt, needswap); 723 if (forw > 0) 724 ufs_add32(sump[forw], -cnt, needswap); 725 726 /* 727 * Update cluster summary information. 728 */ 729 lp = &sump[fs->fs_contigsumsize]; 730 for (i = fs->fs_contigsumsize; i > 0; i--) 731 if (ufs_rw32(*lp--, needswap) > 0) 732 break; 733 fs->fs_maxcluster[ufs_rw32(cgp->cg_cgx, needswap)] = i; 734 } 735