| 1 | /* $NetBSD: msdosfs_fat.c,v 1.31 2016/05/07 16:43:02 mlelstv Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. |
| 5 | * Copyright (C) 1994, 1995, 1997 TooLs GmbH. |
| 6 | * All rights reserved. |
| 7 | * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). |
| 8 | * |
| 9 | * Redistribution and use in source and binary forms, with or without |
| 10 | * modification, are permitted provided that the following conditions |
| 11 | * are met: |
| 12 | * 1. Redistributions of source code must retain the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer. |
| 14 | * 2. Redistributions in binary form must reproduce the above copyright |
| 15 | * notice, this list of conditions and the following disclaimer in the |
| 16 | * documentation and/or other materials provided with the distribution. |
| 17 | * 3. All advertising materials mentioning features or use of this software |
| 18 | * must display the following acknowledgement: |
| 19 | * This product includes software developed by TooLs GmbH. |
| 20 | * 4. The name of TooLs GmbH may not be used to endorse or promote products |
| 21 | * derived from this software without specific prior written permission. |
| 22 | * |
| 23 | * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR |
| 24 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 25 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 26 | * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 27 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 28 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
| 29 | * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| 30 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| 31 | * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| 32 | * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 33 | */ |
| 34 | /* |
| 35 | * Written by Paul Popelka (paulp@uts.amdahl.com) |
| 36 | * |
| 37 | * You can do anything you want with this software, just don't say you wrote |
| 38 | * it, and don't remove this notice. |
| 39 | * |
| 40 | * This software is provided "as is". |
| 41 | * |
| 42 | * The author supplies this software to be publicly redistributed on the |
| 43 | * understanding that the author is not responsible for the correct |
| 44 | * functioning of this software in any circumstances and is not liable for |
| 45 | * any damages caused by this software. |
| 46 | * |
| 47 | * October 1992 |
| 48 | */ |
| 49 | |
| 50 | #if HAVE_NBTOOL_CONFIG_H |
| 51 | #include "nbtool_config.h" |
| 52 | #endif |
| 53 | |
| 54 | #include <sys/cdefs.h> |
| 55 | __KERNEL_RCSID(0, "$NetBSD: msdosfs_fat.c,v 1.31 2016/05/07 16:43:02 mlelstv Exp $" ); |
| 56 | |
| 57 | /* |
| 58 | * kernel include files. |
| 59 | */ |
| 60 | #include <sys/param.h> |
| 61 | #include <sys/file.h> |
| 62 | #ifdef _KERNEL |
| 63 | #include <sys/mount.h> /* to define statvfs structure */ |
| 64 | #include <sys/errno.h> |
| 65 | #include <sys/systm.h> |
| 66 | #include <sys/kauth.h> |
| 67 | #include <sys/dirent.h> |
| 68 | #include <sys/namei.h> |
| 69 | #include <sys/buf.h> |
| 70 | #include <sys/vnode.h> /* to define vattr structure */ |
| 71 | #else |
| 72 | #include <ffs/buf.h> |
| 73 | #endif |
| 74 | |
| 75 | /* |
| 76 | * msdosfs include files. |
| 77 | */ |
| 78 | #include <fs/msdosfs/bpb.h> |
| 79 | #include <fs/msdosfs/msdosfsmount.h> |
| 80 | #include <fs/msdosfs/direntry.h> |
| 81 | #include <fs/msdosfs/denode.h> |
| 82 | #include <fs/msdosfs/fat.h> |
| 83 | |
| 84 | /* |
| 85 | * Fat cache stats. |
| 86 | */ |
| 87 | int fc_fileextends; /* # of file extends */ |
| 88 | int fc_lfcempty; /* # of time last file cluster cache entry |
| 89 | * was empty */ |
| 90 | int fc_bmapcalls; /* # of times pcbmap was called */ |
| 91 | |
| 92 | #define LMMAX 20 |
| 93 | int fc_lmdistance[LMMAX]; /* counters for how far off the last |
| 94 | * cluster mapped entry was. */ |
| 95 | int fc_largedistance; /* off by more than LMMAX */ |
| 96 | int fc_wherefrom, fc_whereto, fc_lastclust; |
| 97 | int pm_fatblocksize; |
| 98 | |
| 99 | #ifdef MSDOSFS_DEBUG |
| 100 | #define DPRINTF(a) printf a |
| 101 | #else |
| 102 | #define DPRINTF(a) |
| 103 | #endif |
| 104 | #ifdef MSDOSFS_DEBUG |
| 105 | void print_fat_stats(void); |
| 106 | |
| 107 | void |
| 108 | print_fat_stats(void) |
| 109 | { |
| 110 | int i; |
| 111 | |
| 112 | printf("fc_fileextends=%d fc_lfcempty=%d fc_bmapcalls=%d " |
| 113 | "fc_largedistance=%d [%d->%d=%d] fc_lastclust=%d pm_fatblocksize=%d\n" , |
| 114 | fc_fileextends, fc_lfcempty, fc_bmapcalls, fc_largedistance, |
| 115 | fc_wherefrom, fc_whereto, fc_whereto-fc_wherefrom, |
| 116 | fc_lastclust, pm_fatblocksize); |
| 117 | |
| 118 | fc_fileextends = fc_lfcempty = fc_bmapcalls = 0; |
| 119 | fc_wherefrom = fc_whereto = fc_lastclust = 0; |
| 120 | |
| 121 | for (i = 0; i < LMMAX; i++) { |
| 122 | printf("%d:%d " , i, fc_lmdistance[i]); |
| 123 | fc_lmdistance[i] = 0; |
| 124 | } |
| 125 | |
| 126 | printf("\n" ); |
| 127 | } |
| 128 | #endif |
| 129 | |
| 130 | static void fatblock(struct msdosfsmount *, u_long, u_long *, u_long *, |
| 131 | u_long *); |
| 132 | void updatefats(struct msdosfsmount *, struct buf *, u_long); |
| 133 | static inline void usemap_free(struct msdosfsmount *, u_long); |
| 134 | static inline void usemap_alloc(struct msdosfsmount *, u_long); |
| 135 | static int fatchain(struct msdosfsmount *, u_long, u_long, u_long); |
| 136 | int chainlength(struct msdosfsmount *, u_long, u_long); |
| 137 | int chainalloc(struct msdosfsmount *, u_long, u_long, u_long, u_long *, |
| 138 | u_long *); |
| 139 | |
| 140 | static void |
| 141 | fatblock(struct msdosfsmount *pmp, u_long ofs, u_long *bnp, u_long *sizep, u_long *bop) |
| 142 | { |
| 143 | u_long bn, size; |
| 144 | |
| 145 | bn = ofs / pmp->pm_fatblocksize * pmp->pm_fatblocksec; |
| 146 | size = min(pmp->pm_fatblocksec, pmp->pm_FATsecs - bn) |
| 147 | * pmp->pm_BytesPerSec; |
| 148 | bn += pmp->pm_fatblk + pmp->pm_curfat * pmp->pm_FATsecs; |
| 149 | |
| 150 | DPRINTF(("%s(ofs=%lu bn=%lu, size=%lu, bo=%lu)\n" , __func__, ofs, bn, |
| 151 | size, ofs % pmp->pm_fatblocksize)); |
| 152 | if (bnp) |
| 153 | *bnp = bn; |
| 154 | if (sizep) |
| 155 | *sizep = size; |
| 156 | if (bop) |
| 157 | *bop = ofs % pmp->pm_fatblocksize; |
| 158 | |
| 159 | pm_fatblocksize = pmp->pm_fatblocksize; |
| 160 | } |
| 161 | |
| 162 | /* |
| 163 | * Map the logical cluster number of a file into a physical disk sector |
| 164 | * that is filesystem relative. |
| 165 | * |
| 166 | * dep - address of denode representing the file of interest |
| 167 | * findcn - file relative cluster whose filesystem relative cluster number |
| 168 | * and/or block number are/is to be found |
| 169 | * bnp - address of where to place the file system relative block number. |
| 170 | * If this pointer is null then don't return this quantity. |
| 171 | * cnp - address of where to place the file system relative cluster number. |
| 172 | * If this pointer is null then don't return this quantity. |
| 173 | * |
| 174 | * NOTE: Either bnp or cnp must be non-null. |
| 175 | * This function has one side effect. If the requested file relative cluster |
| 176 | * is beyond the end of file, then the actual number of clusters in the file |
| 177 | * is returned in *cnp. This is useful for determining how long a directory is. |
| 178 | * If cnp is null, nothing is returned. |
| 179 | */ |
| 180 | int |
| 181 | pcbmap(struct denode *dep, u_long findcn, daddr_t *bnp, u_long *cnp, int *sp) |
| 182 | /* findcn: file relative cluster to get */ |
| 183 | /* bnp: returned filesys rel sector number */ |
| 184 | /* cnp: returned cluster number */ |
| 185 | /* sp: returned block size */ |
| 186 | { |
| 187 | int error; |
| 188 | u_long i; |
| 189 | u_long cn; |
| 190 | u_long prevcn = 0; /* XXX: prevcn could be used unititialized */ |
| 191 | u_long byteoffset; |
| 192 | u_long bn; |
| 193 | u_long bo; |
| 194 | struct buf *bp = NULL; |
| 195 | u_long bp_bn = -1; |
| 196 | struct msdosfsmount *pmp = dep->de_pmp; |
| 197 | u_long bsize; |
| 198 | |
| 199 | fc_bmapcalls++; |
| 200 | |
| 201 | /* |
| 202 | * If they don't give us someplace to return a value then don't |
| 203 | * bother doing anything. |
| 204 | */ |
| 205 | if (bnp == NULL && cnp == NULL && sp == NULL) |
| 206 | return (0); |
| 207 | |
| 208 | cn = dep->de_StartCluster; |
| 209 | DPRINTF(("%s(start cluster=%lu)\n" , __func__, cn)); |
| 210 | /* |
| 211 | * The "file" that makes up the root directory is contiguous, |
| 212 | * permanently allocated, of fixed size, and is not made up of |
| 213 | * clusters. If the cluster number is beyond the end of the root |
| 214 | * directory, then return the number of clusters in the file. |
| 215 | */ |
| 216 | if (cn == MSDOSFSROOT) { |
| 217 | if (dep->de_Attributes & ATTR_DIRECTORY) { |
| 218 | if (de_cn2off(pmp, findcn) >= dep->de_FileSize) { |
| 219 | if (cnp) |
| 220 | *cnp = de_bn2cn(pmp, pmp->pm_rootdirsize); |
| 221 | DPRINTF(("%s(root, %lu ETOOBIG)\n" , __func__, |
| 222 | de_cn2off(pmp, findcn))); |
| 223 | return (E2BIG); |
| 224 | } |
| 225 | if (bnp) |
| 226 | *bnp = pmp->pm_rootdirblk + de_cn2bn(pmp, findcn); |
| 227 | if (cnp) |
| 228 | *cnp = MSDOSFSROOT; |
| 229 | if (sp) |
| 230 | *sp = min(pmp->pm_bpcluster, |
| 231 | dep->de_FileSize - de_cn2off(pmp, findcn)); |
| 232 | DPRINTF(("%s(root, bn=%lu, cn=%u)\n" , __func__, |
| 233 | pmp->pm_rootdirblk + de_cn2bn(pmp, findcn), |
| 234 | MSDOSFSROOT)); |
| 235 | return (0); |
| 236 | } else { /* just an empty file */ |
| 237 | if (cnp) |
| 238 | *cnp = 0; |
| 239 | DPRINTF(("%s(root, empty ETOOBIG)\n" , __func__)); |
| 240 | return (E2BIG); |
| 241 | } |
| 242 | } |
| 243 | |
| 244 | /* |
| 245 | * All other files do I/O in cluster sized blocks |
| 246 | */ |
| 247 | if (sp) |
| 248 | *sp = pmp->pm_bpcluster; |
| 249 | |
| 250 | /* |
| 251 | * Rummage around in the FAT cache, maybe we can avoid tromping |
| 252 | * thru every FAT entry for the file. And, keep track of how far |
| 253 | * off the cache was from where we wanted to be. |
| 254 | */ |
| 255 | i = 0; |
| 256 | fc_lookup(dep, findcn, &i, &cn); |
| 257 | DPRINTF(("%s(bpcluster=%lu i=%lu cn=%lu\n" , __func__, pmp->pm_bpcluster, |
| 258 | i, cn)); |
| 259 | if ((bn = findcn - i) >= LMMAX) { |
| 260 | fc_largedistance++; |
| 261 | fc_wherefrom = i; |
| 262 | fc_whereto = findcn; |
| 263 | fc_lastclust = dep->de_fc[FC_LASTFC].fc_frcn; |
| 264 | } else |
| 265 | fc_lmdistance[bn]++; |
| 266 | |
| 267 | /* |
| 268 | * Handle all other files or directories the normal way. |
| 269 | */ |
| 270 | for (; i < findcn; i++) { |
| 271 | /* |
| 272 | * Stop with all reserved clusters, not just with EOF. |
| 273 | */ |
| 274 | if (cn >= (CLUST_RSRVD & pmp->pm_fatmask)) |
| 275 | goto hiteof; |
| 276 | |
| 277 | /* |
| 278 | * Also stop when cluster is not in the filesystem |
| 279 | */ |
| 280 | if (cn < CLUST_FIRST || cn > pmp->pm_maxcluster) { |
| 281 | DPRINTF(("%s(cn, %lu not in %lu..%lu)\n" , __func__, |
| 282 | cn, (u_long)CLUST_FIRST, pmp->pm_maxcluster)); |
| 283 | if (bp) |
| 284 | brelse(bp, 0); |
| 285 | return (EINVAL); |
| 286 | } |
| 287 | |
| 288 | byteoffset = FATOFS(pmp, cn); |
| 289 | fatblock(pmp, byteoffset, &bn, &bsize, &bo); |
| 290 | if (bn != bp_bn) { |
| 291 | if (bp) |
| 292 | brelse(bp, 0); |
| 293 | error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), bsize, |
| 294 | 0, &bp); |
| 295 | if (error) { |
| 296 | DPRINTF(("%s(bread, %d)\n" , __func__, error)); |
| 297 | return (error); |
| 298 | } |
| 299 | bp_bn = bn; |
| 300 | } |
| 301 | prevcn = cn; |
| 302 | if (bo >= bsize) { |
| 303 | if (bp) |
| 304 | brelse(bp, 0); |
| 305 | DPRINTF(("%s(block, %lu >= %lu)\n" , __func__, bo, |
| 306 | bsize)); |
| 307 | return (EIO); |
| 308 | } |
| 309 | KASSERT(bp != NULL); |
| 310 | if (FAT32(pmp)) |
| 311 | cn = getulong((char *)bp->b_data + bo); |
| 312 | else |
| 313 | cn = getushort((char *)bp->b_data + bo); |
| 314 | if (FAT12(pmp) && (prevcn & 1)) |
| 315 | cn >>= 4; |
| 316 | DPRINTF(("%s(cn=%lu masked=%lu)\n" , __func__, cn, |
| 317 | cn & pmp->pm_fatmask)); |
| 318 | cn &= pmp->pm_fatmask; |
| 319 | } |
| 320 | |
| 321 | if (!MSDOSFSEOF(cn, pmp->pm_fatmask)) { |
| 322 | if (bp) |
| 323 | brelse(bp, 0); |
| 324 | if (bnp) |
| 325 | *bnp = cntobn(pmp, cn); |
| 326 | if (cnp) |
| 327 | *cnp = cn; |
| 328 | DPRINTF(("%s(bn=%lu, cn=%lu)\n" , __func__, cntobn(pmp, cn), |
| 329 | cn)); |
| 330 | fc_setcache(dep, FC_LASTMAP, i, cn); |
| 331 | return (0); |
| 332 | } |
| 333 | |
| 334 | hiteof:; |
| 335 | if (cnp) |
| 336 | *cnp = i; |
| 337 | if (bp) |
| 338 | brelse(bp, 0); |
| 339 | /* update last file cluster entry in the FAT cache */ |
| 340 | fc_setcache(dep, FC_LASTFC, i - 1, prevcn); |
| 341 | DPRINTF(("%s(eof, %lu)\n" , __func__, i)); |
| 342 | return (E2BIG); |
| 343 | } |
| 344 | |
| 345 | /* |
| 346 | * Find the closest entry in the FAT cache to the cluster we are looking |
| 347 | * for. |
| 348 | */ |
| 349 | void |
| 350 | fc_lookup(struct denode *dep, u_long findcn, u_long *frcnp, u_long *fsrcnp) |
| 351 | { |
| 352 | int i; |
| 353 | u_long cn; |
| 354 | struct fatcache *closest = 0; |
| 355 | |
| 356 | for (i = 0; i < FC_SIZE; i++) { |
| 357 | cn = dep->de_fc[i].fc_frcn; |
| 358 | if (cn != FCE_EMPTY && cn <= findcn) { |
| 359 | if (closest == 0 || cn > closest->fc_frcn) |
| 360 | closest = &dep->de_fc[i]; |
| 361 | } |
| 362 | } |
| 363 | if (closest) { |
| 364 | *frcnp = closest->fc_frcn; |
| 365 | *fsrcnp = closest->fc_fsrcn; |
| 366 | } |
| 367 | } |
| 368 | |
| 369 | /* |
| 370 | * Purge the FAT cache in denode dep of all entries relating to file |
| 371 | * relative cluster frcn and beyond. |
| 372 | */ |
| 373 | void |
| 374 | fc_purge(struct denode *dep, u_int frcn) |
| 375 | { |
| 376 | int i; |
| 377 | struct fatcache *fcp; |
| 378 | |
| 379 | fcp = dep->de_fc; |
| 380 | for (i = 0; i < FC_SIZE; i++, fcp++) { |
| 381 | if (fcp->fc_frcn >= frcn) |
| 382 | fcp->fc_frcn = FCE_EMPTY; |
| 383 | } |
| 384 | } |
| 385 | |
| 386 | /* |
| 387 | * Update the FAT. |
| 388 | * If mirroring the FAT, update all copies, with the first copy as last. |
| 389 | * Else update only the current FAT (ignoring the others). |
| 390 | * |
| 391 | * pmp - msdosfsmount structure for filesystem to update |
| 392 | * bp - addr of modified FAT block |
| 393 | * fatbn - block number relative to begin of filesystem of the modified FAT block. |
| 394 | */ |
| 395 | void |
| 396 | updatefats(struct msdosfsmount *pmp, struct buf *bp, u_long fatbn) |
| 397 | { |
| 398 | int i, error; |
| 399 | struct buf *bpn; |
| 400 | |
| 401 | DPRINTF(("%s(pmp %p, bp %p, fatbn %lu)\n" , __func__, pmp, bp, fatbn)); |
| 402 | |
| 403 | /* |
| 404 | * If we have an FSInfo block, update it. |
| 405 | */ |
| 406 | if (pmp->pm_fsinfo) { |
| 407 | u_long cn = pmp->pm_nxtfree; |
| 408 | |
| 409 | if (pmp->pm_freeclustercount |
| 410 | && (pmp->pm_inusemap[cn / N_INUSEBITS] |
| 411 | & (1 << (cn % N_INUSEBITS)))) { |
| 412 | /* |
| 413 | * The cluster indicated in FSInfo isn't free |
| 414 | * any longer. Got get a new free one. |
| 415 | */ |
| 416 | for (cn = 0; cn < pmp->pm_maxcluster; cn++) |
| 417 | if (pmp->pm_inusemap[cn / N_INUSEBITS] != (u_int)-1) |
| 418 | break; |
| 419 | pmp->pm_nxtfree = cn |
| 420 | + ffs(pmp->pm_inusemap[cn / N_INUSEBITS] |
| 421 | ^ (u_int)-1) - 1; |
| 422 | } |
| 423 | /* |
| 424 | * XXX If the fsinfo block is stored on media with |
| 425 | * 2KB or larger sectors, is the fsinfo structure |
| 426 | * padded at the end or in the middle? |
| 427 | */ |
| 428 | if (bread(pmp->pm_devvp, de_bn2kb(pmp, pmp->pm_fsinfo), |
| 429 | pmp->pm_BytesPerSec, B_MODIFY, &bpn) != 0) { |
| 430 | /* |
| 431 | * Ignore the error, but turn off FSInfo update for the future. |
| 432 | */ |
| 433 | pmp->pm_fsinfo = 0; |
| 434 | } else { |
| 435 | struct fsinfo *fp = (struct fsinfo *)bpn->b_data; |
| 436 | |
| 437 | putulong(fp->fsinfree, pmp->pm_freeclustercount); |
| 438 | putulong(fp->fsinxtfree, pmp->pm_nxtfree); |
| 439 | if (pmp->pm_flags & MSDOSFSMNT_WAITONFAT) |
| 440 | bwrite(bpn); |
| 441 | else |
| 442 | bdwrite(bpn); |
| 443 | } |
| 444 | } |
| 445 | |
| 446 | if (pmp->pm_flags & MSDOSFS_FATMIRROR) { |
| 447 | /* |
| 448 | * Now copy the block(s) of the modified FAT to the other copies of |
| 449 | * the FAT and write them out. This is faster than reading in the |
| 450 | * other FATs and then writing them back out. This could tie up |
| 451 | * the FAT for quite a while. Preventing others from accessing it. |
| 452 | * To prevent us from going after the FAT quite so much we use |
| 453 | * delayed writes, unless they specified "synchronous" when the |
| 454 | * filesystem was mounted. If synch is asked for then use |
| 455 | * bwrite()'s and really slow things down. |
| 456 | */ |
| 457 | for (i = 1; i < pmp->pm_FATs; i++) { |
| 458 | fatbn += pmp->pm_FATsecs; |
| 459 | /* getblk() never fails */ |
| 460 | bpn = getblk(pmp->pm_devvp, de_bn2kb(pmp, fatbn), |
| 461 | bp->b_bcount, 0, 0); |
| 462 | memcpy(bpn->b_data, bp->b_data, bp->b_bcount); |
| 463 | if (pmp->pm_flags & MSDOSFSMNT_WAITONFAT) { |
| 464 | error = bwrite(bpn); |
| 465 | if (error) |
| 466 | printf("%s: copy FAT %d (error=%d)\n" , |
| 467 | __func__, i, error); |
| 468 | } else |
| 469 | bdwrite(bpn); |
| 470 | } |
| 471 | } |
| 472 | |
| 473 | /* |
| 474 | * Write out the first (or current) FAT last. |
| 475 | */ |
| 476 | if (pmp->pm_flags & MSDOSFSMNT_WAITONFAT) { |
| 477 | error = bwrite(bp); |
| 478 | if (error) |
| 479 | printf("%s: write FAT (error=%d)\n" , |
| 480 | __func__, error); |
| 481 | } else |
| 482 | bdwrite(bp); |
| 483 | /* |
| 484 | * Maybe update fsinfo sector here? |
| 485 | */ |
| 486 | } |
| 487 | |
| 488 | /* |
| 489 | * Updating entries in 12 bit FATs is a pain in the butt. |
| 490 | * |
| 491 | * The following picture shows where nibbles go when moving from a 12 bit |
| 492 | * cluster number into the appropriate bytes in the FAT. |
| 493 | * |
| 494 | * byte m byte m+1 byte m+2 |
| 495 | * +----+----+ +----+----+ +----+----+ |
| 496 | * | 0 1 | | 2 3 | | 4 5 | FAT bytes |
| 497 | * +----+----+ +----+----+ +----+----+ |
| 498 | * |
| 499 | * +----+----+----+ +----+----+----+ |
| 500 | * | 3 0 1 | | 4 5 2 | |
| 501 | * +----+----+----+ +----+----+----+ |
| 502 | * cluster n cluster n+1 |
| 503 | * |
| 504 | * Where n is even. m = n + (n >> 2) |
| 505 | * |
| 506 | */ |
| 507 | static inline void |
| 508 | usemap_alloc(struct msdosfsmount *pmp, u_long cn) |
| 509 | { |
| 510 | |
| 511 | pmp->pm_inusemap[cn / N_INUSEBITS] |= 1 << (cn % N_INUSEBITS); |
| 512 | pmp->pm_freeclustercount--; |
| 513 | } |
| 514 | |
| 515 | static inline void |
| 516 | usemap_free(struct msdosfsmount *pmp, u_long cn) |
| 517 | { |
| 518 | |
| 519 | pmp->pm_freeclustercount++; |
| 520 | pmp->pm_inusemap[cn / N_INUSEBITS] &= ~(1 << (cn % N_INUSEBITS)); |
| 521 | } |
| 522 | |
| 523 | int |
| 524 | clusterfree(struct msdosfsmount *pmp, u_long cluster, u_long *oldcnp) |
| 525 | { |
| 526 | int error; |
| 527 | u_long oldcn; |
| 528 | |
| 529 | usemap_free(pmp, cluster); |
| 530 | error = fatentry(FAT_GET_AND_SET, pmp, cluster, &oldcn, MSDOSFSFREE); |
| 531 | if (error) { |
| 532 | usemap_alloc(pmp, cluster); |
| 533 | return (error); |
| 534 | } |
| 535 | /* |
| 536 | * If the cluster was successfully marked free, then update |
| 537 | * the count of free clusters, and turn off the "allocated" |
| 538 | * bit in the "in use" cluster bit map. |
| 539 | */ |
| 540 | if (oldcnp) |
| 541 | *oldcnp = oldcn; |
| 542 | return (0); |
| 543 | } |
| 544 | |
| 545 | /* |
| 546 | * Get or Set or 'Get and Set' the cluster'th entry in the FAT. |
| 547 | * |
| 548 | * function - whether to get or set a fat entry |
| 549 | * pmp - address of the msdosfsmount structure for the filesystem |
| 550 | * whose FAT is to be manipulated. |
| 551 | * cn - which cluster is of interest |
| 552 | * oldcontents - address of a word that is to receive the contents of the |
| 553 | * cluster'th entry if this is a get function |
| 554 | * newcontents - the new value to be written into the cluster'th element of |
| 555 | * the FAT if this is a set function. |
| 556 | * |
| 557 | * This function can also be used to free a cluster by setting the FAT entry |
| 558 | * for a cluster to 0. |
| 559 | * |
| 560 | * All copies of the FAT are updated if this is a set function. NOTE: If |
| 561 | * fatentry() marks a cluster as free it does not update the inusemap in |
| 562 | * the msdosfsmount structure. This is left to the caller. |
| 563 | */ |
| 564 | int |
| 565 | fatentry(int function, struct msdosfsmount *pmp, u_long cn, u_long *oldcontents, u_long newcontents) |
| 566 | { |
| 567 | int error; |
| 568 | u_long readcn; |
| 569 | u_long bn, bo, bsize, byteoffset; |
| 570 | struct buf *bp; |
| 571 | |
| 572 | DPRINTF(("%s(func %d, pmp %p, clust %lu, oldcon %p, newcon " "%lx)\n" , |
| 573 | __func__, function, pmp, cn, oldcontents, newcontents)); |
| 574 | |
| 575 | #ifdef DIAGNOSTIC |
| 576 | /* |
| 577 | * Be sure they asked us to do something. |
| 578 | */ |
| 579 | if ((function & (FAT_SET | FAT_GET)) == 0) { |
| 580 | DPRINTF(("%s(): function code doesn't specify get or set\n" , |
| 581 | __func__)); |
| 582 | return (EINVAL); |
| 583 | } |
| 584 | |
| 585 | /* |
| 586 | * If they asked us to return a cluster number but didn't tell us |
| 587 | * where to put it, give them an error. |
| 588 | */ |
| 589 | if ((function & FAT_GET) && oldcontents == NULL) { |
| 590 | DPRINTF(("%s(): get function with no place to put result\n" , |
| 591 | __func__)); |
| 592 | return (EINVAL); |
| 593 | } |
| 594 | #endif |
| 595 | |
| 596 | /* |
| 597 | * Be sure the requested cluster is in the filesystem. |
| 598 | */ |
| 599 | if (cn < CLUST_FIRST || cn > pmp->pm_maxcluster) |
| 600 | return (EINVAL); |
| 601 | |
| 602 | byteoffset = FATOFS(pmp, cn); |
| 603 | fatblock(pmp, byteoffset, &bn, &bsize, &bo); |
| 604 | if ((error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), bsize, |
| 605 | 0, &bp)) != 0) { |
| 606 | return (error); |
| 607 | } |
| 608 | |
| 609 | if (function & FAT_GET) { |
| 610 | if (FAT32(pmp)) |
| 611 | readcn = getulong((char *)bp->b_data + bo); |
| 612 | else |
| 613 | readcn = getushort((char *)bp->b_data + bo); |
| 614 | if (FAT12(pmp) & (cn & 1)) |
| 615 | readcn >>= 4; |
| 616 | readcn &= pmp->pm_fatmask; |
| 617 | *oldcontents = readcn; |
| 618 | } |
| 619 | if (function & FAT_SET) { |
| 620 | switch (pmp->pm_fatmask) { |
| 621 | case FAT12_MASK: |
| 622 | readcn = getushort((char *)bp->b_data + bo); |
| 623 | if (cn & 1) { |
| 624 | readcn &= 0x000f; |
| 625 | readcn |= newcontents << 4; |
| 626 | } else { |
| 627 | readcn &= 0xf000; |
| 628 | readcn |= newcontents & 0xfff; |
| 629 | } |
| 630 | putushort((char *)bp->b_data + bo, readcn); |
| 631 | break; |
| 632 | case FAT16_MASK: |
| 633 | putushort((char *)bp->b_data + bo, newcontents); |
| 634 | break; |
| 635 | case FAT32_MASK: |
| 636 | /* |
| 637 | * According to spec we have to retain the |
| 638 | * high order bits of the FAT entry. |
| 639 | */ |
| 640 | readcn = getulong((char *)bp->b_data + bo); |
| 641 | readcn &= ~FAT32_MASK; |
| 642 | readcn |= newcontents & FAT32_MASK; |
| 643 | putulong((char *)bp->b_data + bo, readcn); |
| 644 | break; |
| 645 | } |
| 646 | updatefats(pmp, bp, bn); |
| 647 | bp = NULL; |
| 648 | pmp->pm_fmod = 1; |
| 649 | } |
| 650 | if (bp) |
| 651 | brelse(bp, 0); |
| 652 | return (0); |
| 653 | } |
| 654 | |
| 655 | /* |
| 656 | * Update a contiguous cluster chain |
| 657 | * |
| 658 | * pmp - mount point |
| 659 | * start - first cluster of chain |
| 660 | * count - number of clusters in chain |
| 661 | * fillwith - what to write into FAT entry of last cluster |
| 662 | */ |
| 663 | static int |
| 664 | fatchain(struct msdosfsmount *pmp, u_long start, u_long count, u_long fillwith) |
| 665 | { |
| 666 | int error; |
| 667 | u_long bn, bo, bsize, byteoffset, readcn, newc; |
| 668 | struct buf *bp; |
| 669 | |
| 670 | DPRINTF(("%s(pmp %p, start %lu, count %lu, fillwith %lx)\n" , __func__, |
| 671 | pmp, start, count, fillwith)); |
| 672 | /* |
| 673 | * Be sure the clusters are in the filesystem. |
| 674 | */ |
| 675 | if (start < CLUST_FIRST || start + count - 1 > pmp->pm_maxcluster) |
| 676 | return (EINVAL); |
| 677 | |
| 678 | while (count > 0) { |
| 679 | byteoffset = FATOFS(pmp, start); |
| 680 | fatblock(pmp, byteoffset, &bn, &bsize, &bo); |
| 681 | error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), bsize, |
| 682 | B_MODIFY, &bp); |
| 683 | if (error) { |
| 684 | return (error); |
| 685 | } |
| 686 | while (count > 0) { |
| 687 | start++; |
| 688 | newc = --count > 0 ? start : fillwith; |
| 689 | switch (pmp->pm_fatmask) { |
| 690 | case FAT12_MASK: |
| 691 | readcn = getushort((char *)bp->b_data + bo); |
| 692 | if (start & 1) { |
| 693 | readcn &= 0xf000; |
| 694 | readcn |= newc & 0xfff; |
| 695 | } else { |
| 696 | readcn &= 0x000f; |
| 697 | readcn |= newc << 4; |
| 698 | } |
| 699 | putushort((char *)bp->b_data + bo, readcn); |
| 700 | bo++; |
| 701 | if (!(start & 1)) |
| 702 | bo++; |
| 703 | break; |
| 704 | case FAT16_MASK: |
| 705 | putushort((char *)bp->b_data + bo, newc); |
| 706 | bo += 2; |
| 707 | break; |
| 708 | case FAT32_MASK: |
| 709 | readcn = getulong((char *)bp->b_data + bo); |
| 710 | readcn &= ~pmp->pm_fatmask; |
| 711 | readcn |= newc & pmp->pm_fatmask; |
| 712 | putulong((char *)bp->b_data + bo, readcn); |
| 713 | bo += 4; |
| 714 | break; |
| 715 | } |
| 716 | if (bo >= bsize) |
| 717 | break; |
| 718 | } |
| 719 | updatefats(pmp, bp, bn); |
| 720 | } |
| 721 | pmp->pm_fmod = 1; |
| 722 | return (0); |
| 723 | } |
| 724 | |
| 725 | /* |
| 726 | * Check the length of a free cluster chain starting at start. |
| 727 | * |
| 728 | * pmp - mount point |
| 729 | * start - start of chain |
| 730 | * count - maximum interesting length |
| 731 | */ |
| 732 | int |
| 733 | chainlength(struct msdosfsmount *pmp, u_long start, u_long count) |
| 734 | { |
| 735 | u_long idx, max_idx; |
| 736 | u_int map; |
| 737 | u_long len; |
| 738 | |
| 739 | max_idx = pmp->pm_maxcluster / N_INUSEBITS; |
| 740 | idx = start / N_INUSEBITS; |
| 741 | start %= N_INUSEBITS; |
| 742 | map = pmp->pm_inusemap[idx]; |
| 743 | map &= ~((1 << start) - 1); |
| 744 | if (map) { |
| 745 | len = ffs(map) - 1 - start; |
| 746 | return (len > count ? count : len); |
| 747 | } |
| 748 | len = N_INUSEBITS - start; |
| 749 | if (len >= count) |
| 750 | return (count); |
| 751 | while (++idx <= max_idx) { |
| 752 | if (len >= count) |
| 753 | break; |
| 754 | if ((map = pmp->pm_inusemap[idx]) != 0) { |
| 755 | len += ffs(map) - 1; |
| 756 | break; |
| 757 | } |
| 758 | len += N_INUSEBITS; |
| 759 | } |
| 760 | return (len > count ? count : len); |
| 761 | } |
| 762 | |
| 763 | /* |
| 764 | * Allocate contigous free clusters. |
| 765 | * |
| 766 | * pmp - mount point. |
| 767 | * start - start of cluster chain. |
| 768 | * count - number of clusters to allocate. |
| 769 | * fillwith - put this value into the FAT entry for the |
| 770 | * last allocated cluster. |
| 771 | * retcluster - put the first allocated cluster's number here. |
| 772 | * got - how many clusters were actually allocated. |
| 773 | */ |
| 774 | int |
| 775 | chainalloc(struct msdosfsmount *pmp, u_long start, u_long count, u_long fillwith, u_long *retcluster, u_long *got) |
| 776 | { |
| 777 | int error; |
| 778 | u_long cl, n; |
| 779 | |
| 780 | for (cl = start, n = count; n-- > 0;) |
| 781 | usemap_alloc(pmp, cl++); |
| 782 | if ((error = fatchain(pmp, start, count, fillwith)) != 0) |
| 783 | return (error); |
| 784 | |
| 785 | DPRINTF(("%s(): allocated cluster chain at %lu (%lu clusters)\n" , |
| 786 | __func__, start, count)); |
| 787 | if (retcluster) |
| 788 | *retcluster = start; |
| 789 | if (got) |
| 790 | *got = count; |
| 791 | return (0); |
| 792 | } |
| 793 | |
| 794 | /* |
| 795 | * Allocate contiguous free clusters. |
| 796 | * |
| 797 | * pmp - mount point. |
| 798 | * start - preferred start of cluster chain. |
| 799 | * count - number of clusters requested. |
| 800 | * fillwith - put this value into the FAT entry for the |
| 801 | * last allocated cluster. |
| 802 | * retcluster - put the first allocated cluster's number here. |
| 803 | * got - how many clusters were actually allocated. |
| 804 | */ |
| 805 | int |
| 806 | clusteralloc(struct msdosfsmount *pmp, u_long start, u_long count, u_long *retcluster, u_long *got) |
| 807 | { |
| 808 | u_long idx; |
| 809 | u_long len, newst, foundl, cn, l; |
| 810 | u_long foundcn = 0; /* XXX: foundcn could be used unititialized */ |
| 811 | u_long fillwith = CLUST_EOFE; |
| 812 | u_int map; |
| 813 | |
| 814 | DPRINTF(("%s(): find %lu clusters\n" , __func__, count)); |
| 815 | if (start) { |
| 816 | if ((len = chainlength(pmp, start, count)) >= count) |
| 817 | return (chainalloc(pmp, start, count, fillwith, retcluster, got)); |
| 818 | } else { |
| 819 | /* |
| 820 | * This is a new file, initialize start |
| 821 | */ |
| 822 | struct timeval tv; |
| 823 | |
| 824 | microtime(&tv); |
| 825 | start = (tv.tv_usec >> 10) | tv.tv_usec; |
| 826 | len = 0; |
| 827 | } |
| 828 | |
| 829 | /* |
| 830 | * Start at a (pseudo) random place to maximize cluster runs |
| 831 | * under multiple writers. |
| 832 | */ |
| 833 | newst = (start * 1103515245 + 12345) % (pmp->pm_maxcluster + 1); |
| 834 | foundl = 0; |
| 835 | |
| 836 | for (cn = newst; cn <= pmp->pm_maxcluster;) { |
| 837 | idx = cn / N_INUSEBITS; |
| 838 | map = pmp->pm_inusemap[idx]; |
| 839 | map |= (1 << (cn % N_INUSEBITS)) - 1; |
| 840 | if (map != (u_int)-1) { |
| 841 | cn = idx * N_INUSEBITS + ffs(map^(u_int)-1) - 1; |
| 842 | if ((l = chainlength(pmp, cn, count)) >= count) |
| 843 | return (chainalloc(pmp, cn, count, fillwith, retcluster, got)); |
| 844 | if (l > foundl) { |
| 845 | foundcn = cn; |
| 846 | foundl = l; |
| 847 | } |
| 848 | cn += l + 1; |
| 849 | continue; |
| 850 | } |
| 851 | cn += N_INUSEBITS - cn % N_INUSEBITS; |
| 852 | } |
| 853 | for (cn = 0; cn < newst;) { |
| 854 | idx = cn / N_INUSEBITS; |
| 855 | map = pmp->pm_inusemap[idx]; |
| 856 | map |= (1 << (cn % N_INUSEBITS)) - 1; |
| 857 | if (map != (u_int)-1) { |
| 858 | cn = idx * N_INUSEBITS + ffs(map^(u_int)-1) - 1; |
| 859 | if ((l = chainlength(pmp, cn, count)) >= count) |
| 860 | return (chainalloc(pmp, cn, count, fillwith, retcluster, got)); |
| 861 | if (l > foundl) { |
| 862 | foundcn = cn; |
| 863 | foundl = l; |
| 864 | } |
| 865 | cn += l + 1; |
| 866 | continue; |
| 867 | } |
| 868 | cn += N_INUSEBITS - cn % N_INUSEBITS; |
| 869 | } |
| 870 | |
| 871 | if (!foundl) |
| 872 | return (ENOSPC); |
| 873 | |
| 874 | if (len) |
| 875 | return (chainalloc(pmp, start, len, fillwith, retcluster, got)); |
| 876 | else |
| 877 | return (chainalloc(pmp, foundcn, foundl, fillwith, retcluster, got)); |
| 878 | } |
| 879 | |
| 880 | |
| 881 | /* |
| 882 | * Free a chain of clusters. |
| 883 | * |
| 884 | * pmp - address of the msdosfs mount structure for the filesystem |
| 885 | * containing the cluster chain to be freed. |
| 886 | * startcluster - number of the 1st cluster in the chain of clusters to be |
| 887 | * freed. |
| 888 | */ |
| 889 | int |
| 890 | freeclusterchain(struct msdosfsmount *pmp, u_long cluster) |
| 891 | { |
| 892 | int error; |
| 893 | struct buf *bp = NULL; |
| 894 | u_long bn, bo, bsize, byteoffset; |
| 895 | u_long readcn, lbn = -1; |
| 896 | |
| 897 | while (cluster >= CLUST_FIRST && cluster <= pmp->pm_maxcluster) { |
| 898 | byteoffset = FATOFS(pmp, cluster); |
| 899 | fatblock(pmp, byteoffset, &bn, &bsize, &bo); |
| 900 | if (lbn != bn) { |
| 901 | if (bp) |
| 902 | updatefats(pmp, bp, lbn); |
| 903 | error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), bsize, |
| 904 | B_MODIFY, &bp); |
| 905 | if (error) { |
| 906 | return (error); |
| 907 | } |
| 908 | lbn = bn; |
| 909 | } |
| 910 | usemap_free(pmp, cluster); |
| 911 | KASSERT(bp != NULL); |
| 912 | switch (pmp->pm_fatmask) { |
| 913 | case FAT12_MASK: |
| 914 | readcn = getushort((char *)bp->b_data + bo); |
| 915 | if (cluster & 1) { |
| 916 | cluster = readcn >> 4; |
| 917 | readcn &= 0x000f; |
| 918 | readcn |= MSDOSFSFREE << 4; |
| 919 | } else { |
| 920 | cluster = readcn; |
| 921 | readcn &= 0xf000; |
| 922 | readcn |= MSDOSFSFREE & 0xfff; |
| 923 | } |
| 924 | putushort((char *)bp->b_data + bo, readcn); |
| 925 | break; |
| 926 | case FAT16_MASK: |
| 927 | cluster = getushort((char *)bp->b_data + bo); |
| 928 | putushort((char *)bp->b_data + bo, MSDOSFSFREE); |
| 929 | break; |
| 930 | case FAT32_MASK: |
| 931 | cluster = getulong((char *)bp->b_data + bo); |
| 932 | putulong((char *)bp->b_data + bo, |
| 933 | (MSDOSFSFREE & FAT32_MASK) | (cluster & ~FAT32_MASK)); |
| 934 | break; |
| 935 | } |
| 936 | cluster &= pmp->pm_fatmask; |
| 937 | } |
| 938 | if (bp) |
| 939 | updatefats(pmp, bp, bn); |
| 940 | return (0); |
| 941 | } |
| 942 | |
| 943 | /* |
| 944 | * Read in FAT blocks looking for free clusters. For every free cluster |
| 945 | * found turn off its corresponding bit in the pm_inusemap. |
| 946 | */ |
| 947 | int |
| 948 | fillinusemap(struct msdosfsmount *pmp) |
| 949 | { |
| 950 | struct buf *bp = NULL; |
| 951 | u_long cn, readcn; |
| 952 | int error; |
| 953 | u_long bn, bo, bsize, byteoffset; |
| 954 | |
| 955 | /* |
| 956 | * Mark all clusters in use, we mark the free ones in the FAT scan |
| 957 | * loop further down. |
| 958 | */ |
| 959 | for (cn = 0; cn < (pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS; cn++) |
| 960 | pmp->pm_inusemap[cn] = (u_int)-1; |
| 961 | |
| 962 | /* |
| 963 | * Figure how many free clusters are in the filesystem by ripping |
| 964 | * through the FAT counting the number of entries whose content is |
| 965 | * zero. These represent free clusters. |
| 966 | */ |
| 967 | pmp->pm_freeclustercount = 0; |
| 968 | for (cn = CLUST_FIRST; cn <= pmp->pm_maxcluster; cn++) { |
| 969 | byteoffset = FATOFS(pmp, cn); |
| 970 | bo = byteoffset % pmp->pm_fatblocksize; |
| 971 | if (!bo || !bp) { |
| 972 | /* Read new FAT block */ |
| 973 | if (bp) |
| 974 | brelse(bp, 0); |
| 975 | fatblock(pmp, byteoffset, &bn, &bsize, NULL); |
| 976 | error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), bsize, |
| 977 | 0, &bp); |
| 978 | if (error) { |
| 979 | return (error); |
| 980 | } |
| 981 | } |
| 982 | if (FAT32(pmp)) |
| 983 | readcn = getulong((char *)bp->b_data + bo); |
| 984 | else |
| 985 | readcn = getushort((char *)bp->b_data + bo); |
| 986 | if (FAT12(pmp) && (cn & 1)) |
| 987 | readcn >>= 4; |
| 988 | readcn &= pmp->pm_fatmask; |
| 989 | |
| 990 | if (readcn == 0) |
| 991 | usemap_free(pmp, cn); |
| 992 | } |
| 993 | if (bp) |
| 994 | brelse(bp, 0); |
| 995 | return (0); |
| 996 | } |
| 997 | |
| 998 | /* |
| 999 | * Allocate a new cluster and chain it onto the end of the file. |
| 1000 | * |
| 1001 | * dep - the file to extend |
| 1002 | * count - number of clusters to allocate |
| 1003 | * bpp - where to return the address of the buf header for the first new |
| 1004 | * file block |
| 1005 | * ncp - where to put cluster number of the first newly allocated cluster |
| 1006 | * If this pointer is 0, do not return the cluster number. |
| 1007 | * flags - see fat.h |
| 1008 | * |
| 1009 | * NOTE: This function is not responsible for turning on the DE_UPDATE bit of |
| 1010 | * the de_flag field of the denode and it does not change the de_FileSize |
| 1011 | * field. This is left for the caller to do. |
| 1012 | */ |
| 1013 | |
| 1014 | int |
| 1015 | extendfile(struct denode *dep, u_long count, struct buf **bpp, u_long *ncp, int flags) |
| 1016 | { |
| 1017 | int error; |
| 1018 | u_long frcn = 0, cn, got; |
| 1019 | struct msdosfsmount *pmp = dep->de_pmp; |
| 1020 | struct buf *bp; |
| 1021 | |
| 1022 | /* |
| 1023 | * Don't try to extend the root directory |
| 1024 | */ |
| 1025 | if (dep->de_StartCluster == MSDOSFSROOT |
| 1026 | && (dep->de_Attributes & ATTR_DIRECTORY)) { |
| 1027 | DPRINTF(("%s(): attempt to extend root directory\n" , __func__)); |
| 1028 | return (ENOSPC); |
| 1029 | } |
| 1030 | |
| 1031 | /* |
| 1032 | * If the "file's last cluster" cache entry is empty, and the file |
| 1033 | * is not empty, then fill the cache entry by calling pcbmap(). |
| 1034 | */ |
| 1035 | fc_fileextends++; |
| 1036 | if (dep->de_fc[FC_LASTFC].fc_frcn == FCE_EMPTY && |
| 1037 | dep->de_StartCluster != 0) { |
| 1038 | fc_lfcempty++; |
| 1039 | error = pcbmap(dep, CLUST_END, 0, &cn, 0); |
| 1040 | /* we expect it to return E2BIG */ |
| 1041 | if (error != E2BIG) |
| 1042 | return (error); |
| 1043 | } |
| 1044 | |
| 1045 | fc_last_to_nexttolast(dep); |
| 1046 | |
| 1047 | while (count > 0) { |
| 1048 | |
| 1049 | /* |
| 1050 | * Allocate a new cluster chain and cat onto the end of the |
| 1051 | * file. If the file is empty we make de_StartCluster point |
| 1052 | * to the new block. Note that de_StartCluster being 0 is |
| 1053 | * sufficient to be sure the file is empty since we exclude |
| 1054 | * attempts to extend the root directory above, and the root |
| 1055 | * dir is the only file with a startcluster of 0 that has |
| 1056 | * blocks allocated (sort of). |
| 1057 | */ |
| 1058 | |
| 1059 | if (dep->de_StartCluster == 0) |
| 1060 | cn = 0; |
| 1061 | else |
| 1062 | cn = dep->de_fc[FC_LASTFC].fc_fsrcn + 1; |
| 1063 | error = clusteralloc(pmp, cn, count, &cn, &got); |
| 1064 | if (error) |
| 1065 | return (error); |
| 1066 | |
| 1067 | count -= got; |
| 1068 | |
| 1069 | /* |
| 1070 | * Give them the filesystem relative cluster number if they want |
| 1071 | * it. |
| 1072 | */ |
| 1073 | if (ncp) { |
| 1074 | *ncp = cn; |
| 1075 | ncp = NULL; |
| 1076 | } |
| 1077 | |
| 1078 | if (dep->de_StartCluster == 0) { |
| 1079 | dep->de_StartCluster = cn; |
| 1080 | frcn = 0; |
| 1081 | } else { |
| 1082 | error = fatentry(FAT_SET, pmp, |
| 1083 | dep->de_fc[FC_LASTFC].fc_fsrcn, |
| 1084 | 0, cn); |
| 1085 | if (error) { |
| 1086 | clusterfree(pmp, cn, NULL); |
| 1087 | return (error); |
| 1088 | } |
| 1089 | frcn = dep->de_fc[FC_LASTFC].fc_frcn + 1; |
| 1090 | } |
| 1091 | |
| 1092 | /* |
| 1093 | * Update the "last cluster of the file" entry in the |
| 1094 | * denode's FAT cache. |
| 1095 | */ |
| 1096 | |
| 1097 | fc_setcache(dep, FC_LASTFC, frcn + got - 1, cn + got - 1); |
| 1098 | if ((flags & DE_CLEAR) && |
| 1099 | (dep->de_Attributes & ATTR_DIRECTORY)) { |
| 1100 | while (got-- > 0) { |
| 1101 | bp = getblk(pmp->pm_devvp, |
| 1102 | de_bn2kb(pmp, cntobn(pmp, cn++)), |
| 1103 | pmp->pm_bpcluster, 0, 0); |
| 1104 | clrbuf(bp); |
| 1105 | if (bpp) { |
| 1106 | *bpp = bp; |
| 1107 | bpp = NULL; |
| 1108 | } else { |
| 1109 | bdwrite(bp); |
| 1110 | } |
| 1111 | } |
| 1112 | } |
| 1113 | } |
| 1114 | |
| 1115 | return (0); |
| 1116 | } |
| 1117 | |