Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/fs/msdosfs/msdosfs_denode.c
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1 /* $FreeBSD: releng/11.0/sys/fs/msdosfs/msdosfs_denode.c 276887 2015-01-09 14:50:08Z emaste $ */ 2 /* $NetBSD: msdosfs_denode.c,v 1.28 1998/02/10 14:10:00 mrg Exp $ */ 3 4 /*- 5 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 6 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 7 * All rights reserved. 8 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by TooLs GmbH. 21 * 4. The name of TooLs GmbH may not be used to endorse or promote products 22 * derived from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 29 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 30 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 31 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 32 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 33 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 /*- 36 * Written by Paul Popelka (paulp@uts.amdahl.com) 37 * 38 * You can do anything you want with this software, just don't say you wrote 39 * it, and don't remove this notice. 40 * 41 * This software is provided "as is". 42 * 43 * The author supplies this software to be publicly redistributed on the 44 * understanding that the author is not responsible for the correct 45 * functioning of this software in any circumstances and is not liable for 46 * any damages caused by this software. 47 * 48 * October 1992 49 */ 50 51 #include <sys/param.h> 52 #include <sys/systm.h> 53 #include <sys/buf.h> 54 #include <sys/clock.h> 55 #include <sys/kernel.h> 56 #include <sys/malloc.h> 57 #include <sys/mount.h> 58 #include <sys/vnode.h> 59 60 #include <vm/vm.h> 61 #include <vm/vm_extern.h> 62 63 #include <fs/msdosfs/bpb.h> 64 #include <fs/msdosfs/direntry.h> 65 #include <fs/msdosfs/denode.h> 66 #include <fs/msdosfs/fat.h> 67 #include <fs/msdosfs/msdosfsmount.h> 68 69 static MALLOC_DEFINE(M_MSDOSFSNODE, "msdosfs_node", "MSDOSFS vnode private part"); 70 71 static int 72 de_vncmpf(struct vnode *vp, void *arg) 73 { 74 struct denode *de; 75 uint64_t *a; 76 77 a = arg; 78 de = VTODE(vp); 79 return (de->de_inode != *a); 80 } 81 82 /* 83 * If deget() succeeds it returns with the gotten denode locked(). 84 * 85 * pmp - address of msdosfsmount structure of the filesystem containing 86 * the denode of interest. The address of 87 * the msdosfsmount structure are used. 88 * dirclust - which cluster bp contains, if dirclust is 0 (root directory) 89 * diroffset is relative to the beginning of the root directory, 90 * otherwise it is cluster relative. 91 * diroffset - offset past begin of cluster of denode we want 92 * depp - returns the address of the gotten denode. 93 */ 94 int 95 deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, 96 struct denode **depp) 97 { 98 int error; 99 uint64_t inode; 100 struct mount *mntp = pmp->pm_mountp; 101 struct direntry *direntptr; 102 struct denode *ldep; 103 struct vnode *nvp, *xvp; 104 struct buf *bp; 105 106 #ifdef MSDOSFS_DEBUG 107 printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n", 108 pmp, dirclust, diroffset, depp); 109 #endif 110 111 /* 112 * On FAT32 filesystems, root is a (more or less) normal 113 * directory 114 */ 115 if (FAT32(pmp) && dirclust == MSDOSFSROOT) 116 dirclust = pmp->pm_rootdirblk; 117 118 /* 119 * See if the denode is in the denode cache. Use the location of 120 * the directory entry to compute the hash value. For subdir use 121 * address of "." entry. For root dir (if not FAT32) use cluster 122 * MSDOSFSROOT, offset MSDOSFSROOT_OFS 123 * 124 * NOTE: The check for de_refcnt > 0 below insures the denode being 125 * examined does not represent an unlinked but still open file. 126 * These files are not to be accessible even when the directory 127 * entry that represented the file happens to be reused while the 128 * deleted file is still open. 129 */ 130 inode = (uint64_t)pmp->pm_bpcluster * dirclust + diroffset; 131 132 error = vfs_hash_get(mntp, inode, LK_EXCLUSIVE, curthread, &nvp, 133 de_vncmpf, &inode); 134 if (error) 135 return (error); 136 if (nvp != NULL) { 137 *depp = VTODE(nvp); 138 KASSERT((*depp)->de_dirclust == dirclust, ("wrong dirclust")); 139 KASSERT((*depp)->de_diroffset == diroffset, ("wrong diroffset")); 140 return (0); 141 } 142 ldep = malloc(sizeof(struct denode), M_MSDOSFSNODE, M_WAITOK | M_ZERO); 143 144 /* 145 * Directory entry was not in cache, have to create a vnode and 146 * copy it from the passed disk buffer. 147 */ 148 /* getnewvnode() does a VREF() on the vnode */ 149 error = getnewvnode("msdosfs", mntp, &msdosfs_vnodeops, &nvp); 150 if (error) { 151 *depp = NULL; 152 free(ldep, M_MSDOSFSNODE); 153 return error; 154 } 155 nvp->v_data = ldep; 156 ldep->de_vnode = nvp; 157 ldep->de_flag = 0; 158 ldep->de_dirclust = dirclust; 159 ldep->de_diroffset = diroffset; 160 ldep->de_inode = inode; 161 lockmgr(nvp->v_vnlock, LK_EXCLUSIVE, NULL); 162 fc_purge(ldep, 0); /* init the fat cache for this denode */ 163 error = insmntque(nvp, mntp); 164 if (error != 0) { 165 free(ldep, M_MSDOSFSNODE); 166 *depp = NULL; 167 return (error); 168 } 169 error = vfs_hash_insert(nvp, inode, LK_EXCLUSIVE, curthread, &xvp, 170 de_vncmpf, &inode); 171 if (error) { 172 *depp = NULL; 173 return (error); 174 } 175 if (xvp != NULL) { 176 *depp = xvp->v_data; 177 return (0); 178 } 179 180 ldep->de_pmp = pmp; 181 ldep->de_refcnt = 1; 182 /* 183 * Copy the directory entry into the denode area of the vnode. 184 */ 185 if ((dirclust == MSDOSFSROOT 186 || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)) 187 && diroffset == MSDOSFSROOT_OFS) { 188 /* 189 * Directory entry for the root directory. There isn't one, 190 * so we manufacture one. We should probably rummage 191 * through the root directory and find a label entry (if it 192 * exists), and then use the time and date from that entry 193 * as the time and date for the root denode. 194 */ 195 nvp->v_vflag |= VV_ROOT; /* should be further down XXX */ 196 197 ldep->de_Attributes = ATTR_DIRECTORY; 198 ldep->de_LowerCase = 0; 199 if (FAT32(pmp)) 200 ldep->de_StartCluster = pmp->pm_rootdirblk; 201 /* de_FileSize will be filled in further down */ 202 else { 203 ldep->de_StartCluster = MSDOSFSROOT; 204 ldep->de_FileSize = pmp->pm_rootdirsize * DEV_BSIZE; 205 } 206 /* 207 * fill in time and date so that fattime2timespec() doesn't 208 * spit up when called from msdosfs_getattr() with root 209 * denode 210 */ 211 ldep->de_CHun = 0; 212 ldep->de_CTime = 0x0000; /* 00:00:00 */ 213 ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT) 214 | (1 << DD_DAY_SHIFT); 215 /* Jan 1, 1980 */ 216 ldep->de_ADate = ldep->de_CDate; 217 ldep->de_MTime = ldep->de_CTime; 218 ldep->de_MDate = ldep->de_CDate; 219 /* leave the other fields as garbage */ 220 } else { 221 error = readep(pmp, dirclust, diroffset, &bp, &direntptr); 222 if (error) { 223 /* 224 * The denode does not contain anything useful, so 225 * it would be wrong to leave it on its hash chain. 226 * Arrange for vput() to just forget about it. 227 */ 228 ldep->de_Name[0] = SLOT_DELETED; 229 230 vput(nvp); 231 *depp = NULL; 232 return (error); 233 } 234 (void)DE_INTERNALIZE(ldep, direntptr); 235 brelse(bp); 236 } 237 238 /* 239 * Fill in a few fields of the vnode and finish filling in the 240 * denode. Then return the address of the found denode. 241 */ 242 if (ldep->de_Attributes & ATTR_DIRECTORY) { 243 /* 244 * Since DOS directory entries that describe directories 245 * have 0 in the filesize field, we take this opportunity 246 * to find out the length of the directory and plug it into 247 * the denode structure. 248 */ 249 u_long size; 250 251 /* 252 * XXX it sometimes happens that the "." entry has cluster 253 * number 0 when it shouldn't. Use the actual cluster number 254 * instead of what is written in directory entry. 255 */ 256 if (diroffset == 0 && ldep->de_StartCluster != dirclust) { 257 #ifdef MSDOSFS_DEBUG 258 printf("deget(): \".\" entry at clust %lu != %lu\n", 259 dirclust, ldep->de_StartCluster); 260 #endif 261 ldep->de_StartCluster = dirclust; 262 } 263 264 nvp->v_type = VDIR; 265 if (ldep->de_StartCluster != MSDOSFSROOT) { 266 error = pcbmap(ldep, 0xffff, 0, &size, 0); 267 if (error == E2BIG) { 268 ldep->de_FileSize = de_cn2off(pmp, size); 269 error = 0; 270 } else { 271 #ifdef MSDOSFS_DEBUG 272 printf("deget(): pcbmap returned %d\n", error); 273 #endif 274 } 275 } 276 } else 277 nvp->v_type = VREG; 278 ldep->de_modrev = init_va_filerev(); 279 *depp = ldep; 280 return (0); 281 } 282 283 int 284 deupdat(struct denode *dep, int waitfor) 285 { 286 struct direntry dir; 287 struct timespec ts; 288 struct buf *bp; 289 struct direntry *dirp; 290 int error; 291 292 if (DETOV(dep)->v_mount->mnt_flag & MNT_RDONLY) { 293 dep->de_flag &= ~(DE_UPDATE | DE_CREATE | DE_ACCESS | 294 DE_MODIFIED); 295 return (0); 296 } 297 getnanotime(&ts); 298 DETIMES(dep, &ts, &ts, &ts); 299 if ((dep->de_flag & DE_MODIFIED) == 0 && waitfor == 0) 300 return (0); 301 dep->de_flag &= ~DE_MODIFIED; 302 if (DETOV(dep)->v_vflag & VV_ROOT) 303 return (EINVAL); 304 if (dep->de_refcnt <= 0) 305 return (0); 306 error = readde(dep, &bp, &dirp); 307 if (error) 308 return (error); 309 DE_EXTERNALIZE(&dir, dep); 310 if (bcmp(dirp, &dir, sizeof(dir)) == 0) { 311 if (waitfor == 0 || (bp->b_flags & B_DELWRI) == 0) { 312 brelse(bp); 313 return (0); 314 } 315 } else 316 *dirp = dir; 317 if ((DETOV(dep)->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0) 318 bp->b_flags |= B_CLUSTEROK; 319 if (waitfor) 320 error = bwrite(bp); 321 else if (vm_page_count_severe() || buf_dirty_count_severe()) 322 bawrite(bp); 323 else 324 bdwrite(bp); 325 return (error); 326 } 327 328 /* 329 * Truncate the file described by dep to the length specified by length. 330 */ 331 int 332 detrunc(struct denode *dep, u_long length, int flags, struct ucred *cred) 333 { 334 int error; 335 int allerror; 336 u_long eofentry; 337 u_long chaintofree; 338 daddr_t bn; 339 int boff; 340 int isadir = dep->de_Attributes & ATTR_DIRECTORY; 341 struct buf *bp; 342 struct msdosfsmount *pmp = dep->de_pmp; 343 344 #ifdef MSDOSFS_DEBUG 345 printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags); 346 #endif 347 348 /* 349 * Disallow attempts to truncate the root directory since it is of 350 * fixed size. That's just the way dos filesystems are. We use 351 * the VROOT bit in the vnode because checking for the directory 352 * bit and a startcluster of 0 in the denode is not adequate to 353 * recognize the root directory at this point in a file or 354 * directory's life. 355 */ 356 if ((DETOV(dep)->v_vflag & VV_ROOT) && !FAT32(pmp)) { 357 #ifdef MSDOSFS_DEBUG 358 printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n", 359 dep->de_dirclust, dep->de_diroffset); 360 #endif 361 return (EINVAL); 362 } 363 364 if (dep->de_FileSize < length) { 365 vnode_pager_setsize(DETOV(dep), length); 366 return deextend(dep, length, cred); 367 } 368 369 /* 370 * If the desired length is 0 then remember the starting cluster of 371 * the file and set the StartCluster field in the directory entry 372 * to 0. If the desired length is not zero, then get the number of 373 * the last cluster in the shortened file. Then get the number of 374 * the first cluster in the part of the file that is to be freed. 375 * Then set the next cluster pointer in the last cluster of the 376 * file to CLUST_EOFE. 377 */ 378 if (length == 0) { 379 chaintofree = dep->de_StartCluster; 380 dep->de_StartCluster = 0; 381 eofentry = ~0; 382 } else { 383 error = pcbmap(dep, de_clcount(pmp, length) - 1, 0, 384 &eofentry, 0); 385 if (error) { 386 #ifdef MSDOSFS_DEBUG 387 printf("detrunc(): pcbmap fails %d\n", error); 388 #endif 389 return (error); 390 } 391 } 392 393 fc_purge(dep, de_clcount(pmp, length)); 394 395 /* 396 * If the new length is not a multiple of the cluster size then we 397 * must zero the tail end of the new last cluster in case it 398 * becomes part of the file again because of a seek. 399 */ 400 if ((boff = length & pmp->pm_crbomask) != 0) { 401 if (isadir) { 402 bn = cntobn(pmp, eofentry); 403 error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster, 404 NOCRED, &bp); 405 if (error) { 406 brelse(bp); 407 #ifdef MSDOSFS_DEBUG 408 printf("detrunc(): bread fails %d\n", error); 409 #endif 410 return (error); 411 } 412 bzero(bp->b_data + boff, pmp->pm_bpcluster - boff); 413 if (flags & IO_SYNC) 414 bwrite(bp); 415 else 416 bdwrite(bp); 417 } 418 } 419 420 /* 421 * Write out the updated directory entry. Even if the update fails 422 * we free the trailing clusters. 423 */ 424 dep->de_FileSize = length; 425 if (!isadir) 426 dep->de_flag |= DE_UPDATE | DE_MODIFIED; 427 allerror = vtruncbuf(DETOV(dep), cred, length, pmp->pm_bpcluster); 428 #ifdef MSDOSFS_DEBUG 429 if (allerror) 430 printf("detrunc(): vtruncbuf error %d\n", allerror); 431 #endif 432 error = deupdat(dep, !DOINGASYNC((DETOV(dep)))); 433 if (error != 0 && allerror == 0) 434 allerror = error; 435 #ifdef MSDOSFS_DEBUG 436 printf("detrunc(): allerror %d, eofentry %lu\n", 437 allerror, eofentry); 438 #endif 439 440 /* 441 * If we need to break the cluster chain for the file then do it 442 * now. 443 */ 444 if (eofentry != ~0) { 445 error = fatentry(FAT_GET_AND_SET, pmp, eofentry, 446 &chaintofree, CLUST_EOFE); 447 if (error) { 448 #ifdef MSDOSFS_DEBUG 449 printf("detrunc(): fatentry errors %d\n", error); 450 #endif 451 return (error); 452 } 453 fc_setcache(dep, FC_LASTFC, de_cluster(pmp, length - 1), 454 eofentry); 455 } 456 457 /* 458 * Now free the clusters removed from the file because of the 459 * truncation. 460 */ 461 if (chaintofree != 0 && !MSDOSFSEOF(pmp, chaintofree)) 462 freeclusterchain(pmp, chaintofree); 463 464 return (allerror); 465 } 466 467 /* 468 * Extend the file described by dep to length specified by length. 469 */ 470 int 471 deextend(struct denode *dep, u_long length, struct ucred *cred) 472 { 473 struct msdosfsmount *pmp = dep->de_pmp; 474 u_long count; 475 int error; 476 477 /* 478 * The root of a DOS filesystem cannot be extended. 479 */ 480 if ((DETOV(dep)->v_vflag & VV_ROOT) && !FAT32(pmp)) 481 return (EINVAL); 482 483 /* 484 * Directories cannot be extended. 485 */ 486 if (dep->de_Attributes & ATTR_DIRECTORY) 487 return (EISDIR); 488 489 if (length <= dep->de_FileSize) 490 panic("deextend: file too large"); 491 492 /* 493 * Compute the number of clusters to allocate. 494 */ 495 count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize); 496 if (count > 0) { 497 if (count > pmp->pm_freeclustercount) 498 return (ENOSPC); 499 error = extendfile(dep, count, NULL, NULL, DE_CLEAR); 500 if (error) { 501 /* truncate the added clusters away again */ 502 (void) detrunc(dep, dep->de_FileSize, 0, cred); 503 return (error); 504 } 505 } 506 dep->de_FileSize = length; 507 dep->de_flag |= DE_UPDATE | DE_MODIFIED; 508 return (deupdat(dep, !DOINGASYNC(DETOV(dep)))); 509 } 510 511 /* 512 * Move a denode to its correct hash queue after the file it represents has 513 * been moved to a new directory. 514 */ 515 void 516 reinsert(struct denode *dep) 517 { 518 struct vnode *vp; 519 520 /* 521 * Fix up the denode cache. If the denode is for a directory, 522 * there is nothing to do since the hash is based on the starting 523 * cluster of the directory file and that hasn't changed. If for a 524 * file the hash is based on the location of the directory entry, 525 * so we must remove it from the cache and re-enter it with the 526 * hash based on the new location of the directory entry. 527 */ 528 #if 0 529 if (dep->de_Attributes & ATTR_DIRECTORY) 530 return; 531 #endif 532 vp = DETOV(dep); 533 dep->de_inode = (uint64_t)dep->de_pmp->pm_bpcluster * dep->de_dirclust + 534 dep->de_diroffset; 535 vfs_hash_rehash(vp, dep->de_inode); 536 } 537 538 int 539 msdosfs_reclaim(struct vop_reclaim_args *ap) 540 { 541 struct vnode *vp = ap->a_vp; 542 struct denode *dep = VTODE(vp); 543 544 #ifdef MSDOSFS_DEBUG 545 printf("msdosfs_reclaim(): dep %p, file %s, refcnt %ld\n", 546 dep, dep->de_Name, dep->de_refcnt); 547 #endif 548 549 /* 550 * Destroy the vm object and flush associated pages. 551 */ 552 vnode_destroy_vobject(vp); 553 /* 554 * Remove the denode from its hash chain. 555 */ 556 vfs_hash_remove(vp); 557 /* 558 * Purge old data structures associated with the denode. 559 */ 560 #if 0 /* XXX */ 561 dep->de_flag = 0; 562 #endif 563 free(dep, M_MSDOSFSNODE); 564 vp->v_data = NULL; 565 566 return (0); 567 } 568 569 int 570 msdosfs_inactive(struct vop_inactive_args *ap) 571 { 572 struct vnode *vp = ap->a_vp; 573 struct denode *dep = VTODE(vp); 574 int error = 0; 575 576 #ifdef MSDOSFS_DEBUG 577 printf("msdosfs_inactive(): dep %p, de_Name[0] %x\n", dep, dep->de_Name[0]); 578 #endif 579 580 /* 581 * Ignore denodes related to stale file handles. 582 */ 583 if (dep->de_Name[0] == SLOT_DELETED || dep->de_Name[0] == SLOT_EMPTY) 584 goto out; 585 586 /* 587 * If the file has been deleted and it is on a read/write 588 * filesystem, then truncate the file, and mark the directory slot 589 * as empty. (This may not be necessary for the dos filesystem.) 590 */ 591 #ifdef MSDOSFS_DEBUG 592 printf("msdosfs_inactive(): dep %p, refcnt %ld, mntflag %x, MNT_RDONLY %x\n", 593 dep, dep->de_refcnt, vp->v_mount->mnt_flag, MNT_RDONLY); 594 #endif 595 if (dep->de_refcnt <= 0 && (vp->v_mount->mnt_flag & MNT_RDONLY) == 0) { 596 error = detrunc(dep, (u_long) 0, 0, NOCRED); 597 dep->de_flag |= DE_UPDATE; 598 dep->de_Name[0] = SLOT_DELETED; 599 } 600 deupdat(dep, 0); 601 602 out: 603 /* 604 * If we are done with the denode, reclaim it 605 * so that it can be reused immediately. 606 */ 607 #ifdef MSDOSFS_DEBUG 608 printf("msdosfs_inactive(): v_usecount %d, de_Name[0] %x\n", 609 vrefcnt(vp), dep->de_Name[0]); 610 #endif 611 if (dep->de_Name[0] == SLOT_DELETED || dep->de_Name[0] == SLOT_EMPTY) 612 vrecycle(vp); 613 return (error); 614 }
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