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 * SPDX-License-Identifier: BSD-3-Clause 6 * 7 * Copyright (c) 2002 Networks Associates Technology, Inc. 8 * All rights reserved. 9 * 10 * This software was developed for the FreeBSD Project by Marshall 11 * Kirk McKusick and Network Associates Laboratories, the Security 12 * Research Division of Network Associates, Inc. under DARPA/SPAWAR 13 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS 14 * research program 15 * 16 * Copyright (c) 1982, 1986, 1989, 1993 17 * The Regents of the University of California. All rights reserved. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 3. Neither the name of the University nor the names of its contributors 28 * may be used to endorse or promote products derived from this software 29 * without specific prior written permission. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 32 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 33 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 34 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 35 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 39 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 40 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 41 * SUCH DAMAGE. 42 * 43 * @(#)ffs_alloc.c 8.19 (Berkeley) 7/13/95 44 * $FreeBSD: head/usr.sbin/makefs/ffs/ffs_alloc.c 336736 2018-07-26 13:33:10Z emaste $ 45 */ 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 <vfs/ufs/dinode.h> 56 #include <vfs/ufs/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 63 #include "ffs.h" /* XXX swildner: for compat defines */ 64 65 static int scanc(u_int, const u_char *, const u_char *, int); 66 67 static makefs_daddr_t ffs_alloccg(struct inode *, int, makefs_daddr_t, int); 68 static makefs_daddr_t ffs_alloccgblk(struct inode *, struct buf *, makefs_daddr_t); 69 static makefs_daddr_t ffs_hashalloc(struct inode *, u_int, makefs_daddr_t, int, 70 makefs_daddr_t (*)(struct inode *, int, makefs_daddr_t, int)); 71 static int32_t ffs_mapsearch(struct fs *, struct cg *, makefs_daddr_t, int); 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) quadratically 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) quadratically rehash into other cylinder groups, until an 90 * available block is located. 91 */ 92 int 93 ffs_alloc(struct inode *ip, makefs_daddr_t lbn __unused, makefs_daddr_t bpref, int size, 94 makefs_daddr_t *bnp) 95 { 96 struct fs *fs = ip->i_fs; 97 makefs_daddr_t bno; 98 int cg; 99 100 *bnp = 0; 101 if (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 = ffs_hashalloc(ip, cg, bpref, size, ffs_alloccg); 114 if (bno > 0) { 115 if (ip->i_fs->fs_magic == FS_UFS1_MAGIC) 116 ip->i_ffs1_blocks += size / DEV_BSIZE; 117 #ifndef __DragonFly__ /* XXX UFS2 */ 118 else 119 ip->i_ffs2_blocks += size / DEV_BSIZE; 120 #endif 121 *bnp = bno; 122 return (0); 123 } 124 nospace: 125 return (ENOSPC); 126 } 127 128 /* 129 * Select the desired position for the next block in a file. The file is 130 * logically divided into sections. The first section is composed of the 131 * direct blocks. Each additional section contains fs_maxbpg blocks. 132 * 133 * If no blocks have been allocated in the first section, the policy is to 134 * request a block in the same cylinder group as the inode that describes 135 * the file. If no blocks have been allocated in any other section, the 136 * policy is to place the section in a cylinder group with a greater than 137 * average number of free blocks. An appropriate cylinder group is found 138 * by using a rotor that sweeps the cylinder groups. When a new group of 139 * blocks is needed, the sweep begins in the cylinder group following the 140 * cylinder group from which the previous allocation was made. The sweep 141 * continues until a cylinder group with greater than the average number 142 * of free blocks is found. If the allocation is for the first block in an 143 * indirect block, the information on the previous allocation is unavailable; 144 * here a best guess is made based upon the logical block number being 145 * allocated. 146 * 147 * If a section is already partially allocated, the policy is to 148 * contiguously allocate fs_maxcontig blocks. The end of one of these 149 * contiguous blocks and the beginning of the next is physically separated 150 * so that the disk head will be in transit between them for at least 151 * fs_rotdelay milliseconds. This is to allow time for the processor to 152 * schedule another I/O transfer. 153 */ 154 /* XXX ondisk32 */ 155 makefs_daddr_t 156 ffs_blkpref_ufs1(struct inode *ip, makefs_daddr_t lbn, int indx, int32_t *bap) 157 { 158 struct fs *fs; 159 u_int cg, startcg; 160 int avgbfree; 161 162 fs = ip->i_fs; 163 if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) { 164 if (lbn < UFS_NDADDR + NINDIR(fs)) { 165 cg = ino_to_cg(fs, ip->i_number); 166 return (fs->fs_fpg * cg + fs->fs_frag); 167 } 168 /* 169 * Find a cylinder with greater than average number of 170 * unused data blocks. 171 */ 172 if (indx == 0 || bap[indx - 1] == 0) 173 startcg = 174 ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg; 175 else 176 startcg = dtog(fs, 177 ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 1); 178 startcg %= fs->fs_ncg; 179 avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg; 180 for (cg = startcg; cg < fs->fs_ncg; cg++) 181 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) 182 return (fs->fs_fpg * cg + fs->fs_frag); 183 for (cg = 0; cg <= startcg; cg++) 184 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) 185 return (fs->fs_fpg * cg + fs->fs_frag); 186 return (0); 187 } 188 /* 189 * We just always try to lay things out contiguously. 190 */ 191 return ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag; 192 } 193 194 #ifndef __DragonFly__ /* XXX UFS2 */ 195 daddr_t 196 ffs_blkpref_ufs2(struct inode *ip, daddr_t lbn, int indx, int64_t *bap) 197 { 198 struct fs *fs; 199 u_int cg, startcg; 200 int avgbfree; 201 202 fs = ip->i_fs; 203 if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) { 204 if (lbn < UFS_NDADDR + NINDIR(fs)) { 205 cg = ino_to_cg(fs, ip->i_number); 206 return (fs->fs_fpg * cg + fs->fs_frag); 207 } 208 /* 209 * Find a cylinder with greater than average number of 210 * unused data blocks. 211 */ 212 if (indx == 0 || bap[indx - 1] == 0) 213 startcg = 214 ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg; 215 else 216 startcg = dtog(fs, 217 ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 1); 218 startcg %= fs->fs_ncg; 219 avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg; 220 for (cg = startcg; cg < fs->fs_ncg; cg++) 221 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) { 222 return (fs->fs_fpg * cg + fs->fs_frag); 223 } 224 for (cg = 0; cg < startcg; cg++) 225 if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) { 226 return (fs->fs_fpg * cg + fs->fs_frag); 227 } 228 return (0); 229 } 230 /* 231 * We just always try to lay things out contiguously. 232 */ 233 return ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag; 234 } 235 #endif 236 237 /* 238 * Implement the cylinder overflow algorithm. 239 * 240 * The policy implemented by this algorithm is: 241 * 1) allocate the block in its requested cylinder group. 242 * 2) quadratically rehash on the cylinder group number. 243 * 3) brute force search for a free block. 244 * 245 * `size': size for data blocks, mode for inodes 246 */ 247 /*VARARGS5*/ 248 static makefs_daddr_t 249 ffs_hashalloc(struct inode *ip, u_int cg, makefs_daddr_t pref, int size, 250 makefs_daddr_t (*allocator)(struct inode *, int, makefs_daddr_t, int)) 251 { 252 struct fs *fs; 253 makefs_daddr_t result; 254 u_int i, icg = cg; 255 256 fs = ip->i_fs; 257 /* 258 * 1: preferred cylinder group 259 */ 260 result = (*allocator)(ip, cg, pref, size); 261 if (result) 262 return (result); 263 /* 264 * 2: quadratic rehash 265 */ 266 for (i = 1; i < fs->fs_ncg; i *= 2) { 267 cg += i; 268 if (cg >= fs->fs_ncg) 269 cg -= fs->fs_ncg; 270 result = (*allocator)(ip, cg, 0, size); 271 if (result) 272 return (result); 273 } 274 /* 275 * 3: brute force search 276 * Note that we start at i == 2, since 0 was checked initially, 277 * and 1 is always checked in the quadratic rehash. 278 */ 279 cg = (icg + 2) % fs->fs_ncg; 280 for (i = 2; i < fs->fs_ncg; i++) { 281 result = (*allocator)(ip, cg, 0, size); 282 if (result) 283 return (result); 284 cg++; 285 if (cg == fs->fs_ncg) 286 cg = 0; 287 } 288 return (0); 289 } 290 291 /* 292 * Determine whether a block can be allocated. 293 * 294 * Check to see if a block of the appropriate size is available, 295 * and if it is, allocate it. 296 */ 297 static makefs_daddr_t 298 ffs_alloccg(struct inode *ip, int cg, makefs_daddr_t bpref, int size) 299 { 300 struct cg *cgp; 301 struct buf *bp; 302 makefs_daddr_t bno, blkno; 303 int error, frags, allocsiz, i; 304 struct fs *fs = ip->i_fs; 305 const int needswap = UFS_FSNEEDSWAP(fs); 306 307 if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize) 308 return (0); 309 error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize, 310 NULL, &bp); 311 if (error) { 312 brelse(bp); 313 return (0); 314 } 315 cgp = (struct cg *)bp->b_data; 316 if (!cg_chkmagic_swap(cgp, needswap) || 317 (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize)) { 318 brelse(bp); 319 return (0); 320 } 321 if (size == fs->fs_bsize) { 322 bno = ffs_alloccgblk(ip, bp, bpref); 323 bdwrite(bp); 324 return (bno); 325 } 326 /* 327 * check to see if any fragments are already available 328 * allocsiz is the size which will be allocated, hacking 329 * it down to a smaller size if necessary 330 */ 331 frags = numfrags(fs, size); 332 for (allocsiz = frags; allocsiz < fs->fs_frag; allocsiz++) 333 if (cgp->cg_frsum[allocsiz] != 0) 334 break; 335 if (allocsiz == fs->fs_frag) { 336 /* 337 * no fragments were available, so a block will be 338 * allocated, and hacked up 339 */ 340 if (cgp->cg_cs.cs_nbfree == 0) { 341 brelse(bp); 342 return (0); 343 } 344 bno = ffs_alloccgblk(ip, bp, bpref); 345 bpref = dtogd(fs, bno); 346 for (i = frags; i < fs->fs_frag; i++) 347 setbit(cg_blksfree_swap(cgp, needswap), bpref + i); 348 i = fs->fs_frag - frags; 349 ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); 350 fs->fs_cstotal.cs_nffree += i; 351 fs->fs_cs(fs, cg).cs_nffree += i; 352 fs->fs_fmod = 1; 353 ufs_add32(cgp->cg_frsum[i], 1, needswap); 354 bdwrite(bp); 355 return (bno); 356 } 357 bno = ffs_mapsearch(fs, cgp, bpref, allocsiz); 358 for (i = 0; i < frags; i++) 359 clrbit(cg_blksfree_swap(cgp, needswap), bno + i); 360 ufs_add32(cgp->cg_cs.cs_nffree, -frags, needswap); 361 fs->fs_cstotal.cs_nffree -= frags; 362 fs->fs_cs(fs, cg).cs_nffree -= frags; 363 fs->fs_fmod = 1; 364 ufs_add32(cgp->cg_frsum[allocsiz], -1, needswap); 365 if (frags != allocsiz) 366 ufs_add32(cgp->cg_frsum[allocsiz - frags], 1, needswap); 367 blkno = cg * fs->fs_fpg + bno; 368 bdwrite(bp); 369 return blkno; 370 } 371 372 /* 373 * Allocate a block in a cylinder group. 374 * 375 * This algorithm implements the following policy: 376 * 1) allocate the requested block. 377 * 2) allocate a rotationally optimal block in the same cylinder. 378 * 3) allocate the next available block on the block rotor for the 379 * specified cylinder group. 380 * Note that this routine only allocates fs_bsize blocks; these 381 * blocks may be fragmented by the routine that allocates them. 382 */ 383 static makefs_daddr_t 384 ffs_alloccgblk(struct inode *ip, struct buf *bp, makefs_daddr_t bpref) 385 { 386 struct cg *cgp; 387 makefs_daddr_t blkno; 388 int32_t bno; 389 struct fs *fs = ip->i_fs; 390 const int needswap = UFS_FSNEEDSWAP(fs); 391 u_int8_t *blksfree_swap; 392 393 cgp = (struct cg *)bp->b_data; 394 blksfree_swap = cg_blksfree_swap(cgp, needswap); 395 if (bpref == 0 || (uint32_t)dtog(fs, bpref) != ufs_rw32(cgp->cg_cgx, needswap)) { 396 bpref = ufs_rw32(cgp->cg_rotor, needswap); 397 } else { 398 bpref = blknum(fs, bpref); 399 bno = dtogd(fs, bpref); 400 /* 401 * if the requested block is available, use it 402 */ 403 if (ffs_isblock(fs, blksfree_swap, fragstoblks(fs, bno))) 404 goto gotit; 405 } 406 /* 407 * Take the next available one in this cylinder group. 408 */ 409 bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag); 410 if (bno < 0) 411 return (0); 412 cgp->cg_rotor = ufs_rw32(bno, needswap); 413 gotit: 414 blkno = fragstoblks(fs, bno); 415 ffs_clrblock(fs, blksfree_swap, (long)blkno); 416 ffs_clusteracct(fs, cgp, blkno, -1); 417 ufs_add32(cgp->cg_cs.cs_nbfree, -1, needswap); 418 fs->fs_cstotal.cs_nbfree--; 419 fs->fs_cs(fs, ufs_rw32(cgp->cg_cgx, needswap)).cs_nbfree--; 420 #ifdef __DragonFly__ /* XXX swildner: our fsck checks these */ 421 cg_blks(fs, cgp, cbtocylno(fs, bno))[cbtorpos(fs, bno)]--; 422 cg_blktot(cgp)[cbtocylno(fs, bno)]--; 423 #endif 424 fs->fs_fmod = 1; 425 blkno = ufs_rw32(cgp->cg_cgx, needswap) * fs->fs_fpg + bno; 426 return (blkno); 427 } 428 429 /* 430 * Free a block or fragment. 431 * 432 * The specified block or fragment is placed back in the 433 * free map. If a fragment is deallocated, a possible 434 * block reassembly is checked. 435 */ 436 void 437 ffs_blkfree(struct inode *ip, makefs_daddr_t bno, long size) 438 { 439 struct cg *cgp; 440 struct buf *bp; 441 int32_t fragno, cgbno; 442 int i, error, cg, blk, frags, bbase; 443 struct fs *fs = ip->i_fs; 444 const int needswap = UFS_FSNEEDSWAP(fs); 445 446 if (size > fs->fs_bsize || fragoff(fs, size) != 0 || 447 fragnum(fs, bno) + numfrags(fs, size) > fs->fs_frag) { 448 errx(1, "blkfree: bad size: bno %lld bsize %d size %ld", 449 (long long)bno, fs->fs_bsize, size); 450 } 451 cg = dtog(fs, bno); 452 if (bno >= fs->fs_size) { 453 warnx("bad block %lld, ino %ju", (long long)bno, 454 (uintmax_t)ip->i_number); 455 return; 456 } 457 error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize, 458 NULL, &bp); 459 if (error) { 460 brelse(bp); 461 return; 462 } 463 cgp = (struct cg *)bp->b_data; 464 if (!cg_chkmagic_swap(cgp, needswap)) { 465 brelse(bp); 466 return; 467 } 468 cgbno = dtogd(fs, bno); 469 if (size == fs->fs_bsize) { 470 fragno = fragstoblks(fs, cgbno); 471 if (!ffs_isfreeblock(fs, cg_blksfree_swap(cgp, needswap), fragno)) { 472 errx(1, "blkfree: freeing free block %lld", 473 (long long)bno); 474 } 475 ffs_setblock(fs, cg_blksfree_swap(cgp, needswap), fragno); 476 ffs_clusteracct(fs, cgp, fragno, 1); 477 ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); 478 fs->fs_cstotal.cs_nbfree++; 479 fs->fs_cs(fs, cg).cs_nbfree++; 480 #ifdef __DragonFly__ /* XXX swildner: our fsck checks these */ 481 cg_blks(fs, cgp, cbtocylno(fs, bno))[cbtorpos(fs, bno)]++; 482 cg_blktot(cgp)[cbtocylno(fs, bno)]++; 483 #endif 484 } else { 485 bbase = cgbno - fragnum(fs, cgbno); 486 /* 487 * decrement the counts associated with the old frags 488 */ 489 blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bbase); 490 ffs_fragacct_swap(fs, blk, cgp->cg_frsum, -1, needswap); 491 /* 492 * deallocate the fragment 493 */ 494 frags = numfrags(fs, size); 495 for (i = 0; i < frags; i++) { 496 if (isset(cg_blksfree_swap(cgp, needswap), cgbno + i)) { 497 errx(1, "blkfree: freeing free frag: block %lld", 498 (long long)(cgbno + i)); 499 } 500 setbit(cg_blksfree_swap(cgp, needswap), cgbno + i); 501 } 502 ufs_add32(cgp->cg_cs.cs_nffree, i, needswap); 503 fs->fs_cstotal.cs_nffree += i; 504 fs->fs_cs(fs, cg).cs_nffree += i; 505 /* 506 * add back in counts associated with the new frags 507 */ 508 blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bbase); 509 ffs_fragacct_swap(fs, blk, cgp->cg_frsum, 1, needswap); 510 /* 511 * if a complete block has been reassembled, account for it 512 */ 513 fragno = fragstoblks(fs, bbase); 514 if (ffs_isblock(fs, cg_blksfree_swap(cgp, needswap), fragno)) { 515 ufs_add32(cgp->cg_cs.cs_nffree, -fs->fs_frag, needswap); 516 fs->fs_cstotal.cs_nffree -= fs->fs_frag; 517 fs->fs_cs(fs, cg).cs_nffree -= fs->fs_frag; 518 ffs_clusteracct(fs, cgp, fragno, 1); 519 ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap); 520 fs->fs_cstotal.cs_nbfree++; 521 fs->fs_cs(fs, cg).cs_nbfree++; 522 #ifdef __DragonFly__ /* XXX swildner: our fsck checks these */ 523 cg_blks(fs, cgp, 524 cbtocylno(fs, bbase))[cbtorpos(fs, bbase)]++; 525 cg_blktot(cgp)[cbtocylno(fs, bbase)]++; 526 #endif 527 } 528 } 529 fs->fs_fmod = 1; 530 bdwrite(bp); 531 } 532 533 534 static int 535 scanc(u_int size, const u_char *cp, const u_char table[], int mask) 536 { 537 const u_char *end = &cp[size]; 538 539 while (cp < end && (table[*cp] & mask) == 0) 540 cp++; 541 return (end - cp); 542 } 543 544 /* 545 * Find a block of the specified size in the specified cylinder group. 546 * 547 * It is a panic if a request is made to find a block if none are 548 * available. 549 */ 550 static int32_t 551 ffs_mapsearch(struct fs *fs, struct cg *cgp, makefs_daddr_t bpref, int allocsiz) 552 { 553 int32_t bno; 554 int start, len, loc, i; 555 int blk, field, subfield, pos; 556 int ostart, olen; 557 const int needswap = UFS_FSNEEDSWAP(fs); 558 559 /* 560 * find the fragment by searching through the free block 561 * map for an appropriate bit pattern 562 */ 563 if (bpref) 564 start = dtogd(fs, bpref) / NBBY; 565 else 566 start = ufs_rw32(cgp->cg_frotor, needswap) / NBBY; 567 len = howmany(fs->fs_fpg, NBBY) - start; 568 ostart = start; 569 olen = len; 570 loc = scanc((u_int)len, 571 (const u_char *)&cg_blksfree_swap(cgp, needswap)[start], 572 (const u_char *)fragtbl[fs->fs_frag], 573 (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); 574 if (loc == 0) { 575 len = start + 1; 576 start = 0; 577 loc = scanc((u_int)len, 578 (const u_char *)&cg_blksfree_swap(cgp, needswap)[0], 579 (const u_char *)fragtbl[fs->fs_frag], 580 (1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); 581 if (loc == 0) { 582 errx(1, 583 "ffs_alloccg: map corrupted: start %d len %d offset %d %ld", 584 ostart, olen, 585 ufs_rw32(cgp->cg_freeoff, needswap), 586 (long)cg_blksfree_swap(cgp, needswap) - (long)cgp); 587 /* NOTREACHED */ 588 } 589 } 590 bno = (start + len - loc) * NBBY; 591 cgp->cg_frotor = ufs_rw32(bno, needswap); 592 /* 593 * found the byte in the map 594 * sift through the bits to find the selected frag 595 */ 596 for (i = bno + NBBY; bno < i; bno += fs->fs_frag) { 597 blk = blkmap(fs, cg_blksfree_swap(cgp, needswap), bno); 598 blk <<= 1; 599 field = around[allocsiz]; 600 subfield = inside[allocsiz]; 601 for (pos = 0; pos <= fs->fs_frag - allocsiz; pos++) { 602 if ((blk & field) == subfield) 603 return (bno + pos); 604 field <<= 1; 605 subfield <<= 1; 606 } 607 } 608 errx(1, "ffs_alloccg: block not in map: bno %lld", (long long)bno); 609 return (-1); 610 } 611 612 /* 613 * Update the cluster map because of an allocation or free. 614 * 615 * Cnt == 1 means free; cnt == -1 means allocating. 616 */ 617 void 618 ffs_clusteracct(struct fs *fs, struct cg *cgp, int32_t blkno, int cnt) 619 { 620 int32_t *sump; 621 int32_t *lp; 622 u_char *freemapp, *mapp; 623 int i, start, end, forw, back, map, bit; 624 const int needswap = UFS_FSNEEDSWAP(fs); 625 626 if (fs->fs_contigsumsize <= 0) 627 return; 628 freemapp = cg_clustersfree_swap(cgp, needswap); 629 sump = cg_clustersum_swap(cgp, needswap); 630 /* 631 * Allocate or clear the actual block. 632 */ 633 if (cnt > 0) 634 setbit(freemapp, blkno); 635 else 636 clrbit(freemapp, blkno); 637 /* 638 * Find the size of the cluster going forward. 639 */ 640 start = blkno + 1; 641 end = start + fs->fs_contigsumsize; 642 if ((unsigned)end >= ufs_rw32(cgp->cg_nclusterblks, needswap)) 643 end = ufs_rw32(cgp->cg_nclusterblks, needswap); 644 mapp = &freemapp[start / NBBY]; 645 map = *mapp++; 646 bit = 1 << (start % NBBY); 647 for (i = start; i < end; i++) { 648 if ((map & bit) == 0) 649 break; 650 if ((i & (NBBY - 1)) != (NBBY - 1)) { 651 bit <<= 1; 652 } else { 653 map = *mapp++; 654 bit = 1; 655 } 656 } 657 forw = i - start; 658 /* 659 * Find the size of the cluster going backward. 660 */ 661 start = blkno - 1; 662 end = start - fs->fs_contigsumsize; 663 if (end < 0) 664 end = -1; 665 mapp = &freemapp[start / NBBY]; 666 map = *mapp--; 667 bit = 1 << (start % NBBY); 668 for (i = start; i > end; i--) { 669 if ((map & bit) == 0) 670 break; 671 if ((i & (NBBY - 1)) != 0) { 672 bit >>= 1; 673 } else { 674 map = *mapp--; 675 bit = 1 << (NBBY - 1); 676 } 677 } 678 back = start - i; 679 /* 680 * Account for old cluster and the possibly new forward and 681 * back clusters. 682 */ 683 i = back + forw + 1; 684 if (i > fs->fs_contigsumsize) 685 i = fs->fs_contigsumsize; 686 ufs_add32(sump[i], cnt, needswap); 687 if (back > 0) 688 ufs_add32(sump[back], -cnt, needswap); 689 if (forw > 0) 690 ufs_add32(sump[forw], -cnt, needswap); 691 692 /* 693 * Update cluster summary information. 694 */ 695 lp = &sump[fs->fs_contigsumsize]; 696 for (i = fs->fs_contigsumsize; i > 0; i--) 697 if (ufs_rw32(*lp--, needswap) > 0) 698 break; 699 fs->fs_maxcluster[ufs_rw32(cgp->cg_cgx, needswap)] = i; 700 } 701