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/9.0/sys/fs/msdosfs/msdosfs_denode.c 215548 2010-11-19 21:17:34Z kib $ */ 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(pmp, dirclust, diroffset, depp) 96 struct msdosfsmount *pmp; /* so we know the maj/min number */ 97 u_long dirclust; /* cluster this dir entry came from */ 98 u_long diroffset; /* index of entry within the cluster */ 99 struct denode **depp; /* returns the addr of the gotten denode */ 100 { 101 int error; 102 uint64_t inode; 103 struct mount *mntp = pmp->pm_mountp; 104 struct direntry *direntptr; 105 struct denode *ldep; 106 struct vnode *nvp, *xvp; 107 struct buf *bp; 108 109 #ifdef MSDOSFS_DEBUG 110 printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n", 111 pmp, dirclust, diroffset, depp); 112 #endif 113 114 /* 115 * On FAT32 filesystems, root is a (more or less) normal 116 * directory 117 */ 118 if (FAT32(pmp) && dirclust == MSDOSFSROOT) 119 dirclust = pmp->pm_rootdirblk; 120 121 /* 122 * See if the denode is in the denode cache. Use the location of 123 * the directory entry to compute the hash value. For subdir use 124 * address of "." entry. For root dir (if not FAT32) use cluster 125 * MSDOSFSROOT, offset MSDOSFSROOT_OFS 126 * 127 * NOTE: The check for de_refcnt > 0 below insures the denode being 128 * examined does not represent an unlinked but still open file. 129 * These files are not to be accessible even when the directory 130 * entry that represented the file happens to be reused while the 131 * deleted file is still open. 132 */ 133 inode = (uint64_t)pmp->pm_bpcluster * dirclust + diroffset; 134 135 error = vfs_hash_get(mntp, inode, LK_EXCLUSIVE, curthread, &nvp, 136 de_vncmpf, &inode); 137 if (error) 138 return (error); 139 if (nvp != NULL) { 140 *depp = VTODE(nvp); 141 KASSERT((*depp)->de_dirclust == dirclust, ("wrong dirclust")); 142 KASSERT((*depp)->de_diroffset == diroffset, ("wrong diroffset")); 143 return (0); 144 } 145 146 /* 147 * Do the malloc before the getnewvnode since doing so afterward 148 * might cause a bogus v_data pointer to get dereferenced 149 * elsewhere if malloc should block. 150 */ 151 ldep = malloc(sizeof(struct denode), M_MSDOSFSNODE, M_WAITOK | M_ZERO); 152 153 /* 154 * Directory entry was not in cache, have to create a vnode and 155 * copy it from the passed disk buffer. 156 */ 157 /* getnewvnode() does a VREF() on the vnode */ 158 error = getnewvnode("msdosfs", mntp, &msdosfs_vnodeops, &nvp); 159 if (error) { 160 *depp = NULL; 161 free(ldep, M_MSDOSFSNODE); 162 return error; 163 } 164 nvp->v_data = ldep; 165 ldep->de_vnode = nvp; 166 ldep->de_flag = 0; 167 ldep->de_dirclust = dirclust; 168 ldep->de_diroffset = diroffset; 169 ldep->de_inode = inode; 170 lockmgr(nvp->v_vnlock, LK_EXCLUSIVE, NULL); 171 fc_purge(ldep, 0); /* init the fat cache for this denode */ 172 error = insmntque(nvp, mntp); 173 if (error != 0) { 174 free(ldep, M_MSDOSFSNODE); 175 *depp = NULL; 176 return (error); 177 } 178 error = vfs_hash_insert(nvp, inode, LK_EXCLUSIVE, curthread, &xvp, 179 de_vncmpf, &inode); 180 if (error) { 181 *depp = NULL; 182 return (error); 183 } 184 if (xvp != NULL) { 185 *depp = xvp->v_data; 186 return (0); 187 } 188 189 ldep->de_pmp = pmp; 190 ldep->de_refcnt = 1; 191 /* 192 * Copy the directory entry into the denode area of the vnode. 193 */ 194 if ((dirclust == MSDOSFSROOT 195 || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)) 196 && diroffset == MSDOSFSROOT_OFS) { 197 /* 198 * Directory entry for the root directory. There isn't one, 199 * so we manufacture one. We should probably rummage 200 * through the root directory and find a label entry (if it 201 * exists), and then use the time and date from that entry 202 * as the time and date for the root denode. 203 */ 204 nvp->v_vflag |= VV_ROOT; /* should be further down XXX */ 205 206 ldep->de_Attributes = ATTR_DIRECTORY; 207 ldep->de_LowerCase = 0; 208 if (FAT32(pmp)) 209 ldep->de_StartCluster = pmp->pm_rootdirblk; 210 /* de_FileSize will be filled in further down */ 211 else { 212 ldep->de_StartCluster = MSDOSFSROOT; 213 ldep->de_FileSize = pmp->pm_rootdirsize * DEV_BSIZE; 214 } 215 /* 216 * fill in time and date so that fattime2timespec() doesn't 217 * spit up when called from msdosfs_getattr() with root 218 * denode 219 */ 220 ldep->de_CHun = 0; 221 ldep->de_CTime = 0x0000; /* 00:00:00 */ 222 ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT) 223 | (1 << DD_DAY_SHIFT); 224 /* Jan 1, 1980 */ 225 ldep->de_ADate = ldep->de_CDate; 226 ldep->de_MTime = ldep->de_CTime; 227 ldep->de_MDate = ldep->de_CDate; 228 /* leave the other fields as garbage */ 229 } else { 230 error = readep(pmp, dirclust, diroffset, &bp, &direntptr); 231 if (error) { 232 /* 233 * The denode does not contain anything useful, so 234 * it would be wrong to leave it on its hash chain. 235 * Arrange for vput() to just forget about it. 236 */ 237 ldep->de_Name[0] = SLOT_DELETED; 238 239 vput(nvp); 240 *depp = NULL; 241 return (error); 242 } 243 (void)DE_INTERNALIZE(ldep, direntptr); 244 brelse(bp); 245 } 246 247 /* 248 * Fill in a few fields of the vnode and finish filling in the 249 * denode. Then return the address of the found denode. 250 */ 251 if (ldep->de_Attributes & ATTR_DIRECTORY) { 252 /* 253 * Since DOS directory entries that describe directories 254 * have 0 in the filesize field, we take this opportunity 255 * to find out the length of the directory and plug it into 256 * the denode structure. 257 */ 258 u_long size; 259 260 /* 261 * XXX it sometimes happens that the "." entry has cluster 262 * number 0 when it shouldn't. Use the actual cluster number 263 * instead of what is written in directory entry. 264 */ 265 if (diroffset == 0 && ldep->de_StartCluster != dirclust) { 266 printf("deget(): \".\" entry at clust %lu != %lu\n", 267 dirclust, ldep->de_StartCluster); 268 ldep->de_StartCluster = dirclust; 269 } 270 271 nvp->v_type = VDIR; 272 if (ldep->de_StartCluster != MSDOSFSROOT) { 273 error = pcbmap(ldep, 0xffff, 0, &size, 0); 274 if (error == E2BIG) { 275 ldep->de_FileSize = de_cn2off(pmp, size); 276 error = 0; 277 } else 278 printf("deget(): pcbmap returned %d\n", error); 279 } 280 } else 281 nvp->v_type = VREG; 282 ldep->de_modrev = init_va_filerev(); 283 *depp = ldep; 284 return (0); 285 } 286 287 int 288 deupdat(dep, waitfor) 289 struct denode *dep; 290 int waitfor; 291 { 292 int error; 293 struct buf *bp; 294 struct direntry *dirp; 295 struct timespec ts; 296 297 if (DETOV(dep)->v_mount->mnt_flag & MNT_RDONLY) 298 return (0); 299 getnanotime(&ts); 300 DETIMES(dep, &ts, &ts, &ts); 301 if ((dep->de_flag & DE_MODIFIED) == 0) 302 return (0); 303 dep->de_flag &= ~DE_MODIFIED; 304 if (dep->de_Attributes & ATTR_DIRECTORY) 305 return (0); 306 if (dep->de_refcnt <= 0) 307 return (0); 308 error = readde(dep, &bp, &dirp); 309 if (error) 310 return (error); 311 DE_EXTERNALIZE(dirp, dep); 312 if (waitfor) 313 return (bwrite(bp)); 314 else { 315 bdwrite(bp); 316 return (0); 317 } 318 } 319 320 /* 321 * Truncate the file described by dep to the length specified by length. 322 */ 323 int 324 detrunc(dep, length, flags, cred, td) 325 struct denode *dep; 326 u_long length; 327 int flags; 328 struct ucred *cred; 329 struct thread *td; 330 { 331 int error; 332 int allerror; 333 u_long eofentry; 334 u_long chaintofree; 335 daddr_t bn; 336 int boff; 337 int isadir = dep->de_Attributes & ATTR_DIRECTORY; 338 struct buf *bp; 339 struct msdosfsmount *pmp = dep->de_pmp; 340 341 #ifdef MSDOSFS_DEBUG 342 printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags); 343 #endif 344 345 /* 346 * Disallow attempts to truncate the root directory since it is of 347 * fixed size. That's just the way dos filesystems are. We use 348 * the VROOT bit in the vnode because checking for the directory 349 * bit and a startcluster of 0 in the denode is not adequate to 350 * recognize the root directory at this point in a file or 351 * directory's life. 352 */ 353 if ((DETOV(dep)->v_vflag & VV_ROOT) && !FAT32(pmp)) { 354 printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n", 355 dep->de_dirclust, dep->de_diroffset); 356 return (EINVAL); 357 } 358 359 if (dep->de_FileSize < length) { 360 vnode_pager_setsize(DETOV(dep), length); 361 return deextend(dep, length, cred); 362 } 363 364 /* 365 * If the desired length is 0 then remember the starting cluster of 366 * the file and set the StartCluster field in the directory entry 367 * to 0. If the desired length is not zero, then get the number of 368 * the last cluster in the shortened file. Then get the number of 369 * the first cluster in the part of the file that is to be freed. 370 * Then set the next cluster pointer in the last cluster of the 371 * file to CLUST_EOFE. 372 */ 373 if (length == 0) { 374 chaintofree = dep->de_StartCluster; 375 dep->de_StartCluster = 0; 376 eofentry = ~0; 377 } else { 378 error = pcbmap(dep, de_clcount(pmp, length) - 1, 0, 379 &eofentry, 0); 380 if (error) { 381 #ifdef MSDOSFS_DEBUG 382 printf("detrunc(): pcbmap fails %d\n", error); 383 #endif 384 return (error); 385 } 386 } 387 388 fc_purge(dep, de_clcount(pmp, length)); 389 390 /* 391 * If the new length is not a multiple of the cluster size then we 392 * must zero the tail end of the new last cluster in case it 393 * becomes part of the file again because of a seek. 394 */ 395 if ((boff = length & pmp->pm_crbomask) != 0) { 396 if (isadir) { 397 bn = cntobn(pmp, eofentry); 398 error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster, 399 NOCRED, &bp); 400 if (error) { 401 brelse(bp); 402 #ifdef MSDOSFS_DEBUG 403 printf("detrunc(): bread fails %d\n", error); 404 #endif 405 return (error); 406 } 407 bzero(bp->b_data + boff, pmp->pm_bpcluster - boff); 408 if (flags & IO_SYNC) 409 bwrite(bp); 410 else 411 bdwrite(bp); 412 } 413 } 414 415 /* 416 * Write out the updated directory entry. Even if the update fails 417 * we free the trailing clusters. 418 */ 419 dep->de_FileSize = length; 420 if (!isadir) 421 dep->de_flag |= DE_UPDATE | DE_MODIFIED; 422 allerror = vtruncbuf(DETOV(dep), cred, td, length, pmp->pm_bpcluster); 423 #ifdef MSDOSFS_DEBUG 424 if (allerror) 425 printf("detrunc(): vtruncbuf error %d\n", allerror); 426 #endif 427 error = deupdat(dep, !(DETOV(dep)->v_mount->mnt_flag & MNT_ASYNC)); 428 if (error != 0 && allerror == 0) 429 allerror = error; 430 #ifdef MSDOSFS_DEBUG 431 printf("detrunc(): allerror %d, eofentry %lu\n", 432 allerror, eofentry); 433 #endif 434 435 /* 436 * If we need to break the cluster chain for the file then do it 437 * now. 438 */ 439 if (eofentry != ~0) { 440 error = fatentry(FAT_GET_AND_SET, pmp, eofentry, 441 &chaintofree, CLUST_EOFE); 442 if (error) { 443 #ifdef MSDOSFS_DEBUG 444 printf("detrunc(): fatentry errors %d\n", error); 445 #endif 446 return (error); 447 } 448 fc_setcache(dep, FC_LASTFC, de_cluster(pmp, length - 1), 449 eofentry); 450 } 451 452 /* 453 * Now free the clusters removed from the file because of the 454 * truncation. 455 */ 456 if (chaintofree != 0 && !MSDOSFSEOF(pmp, chaintofree)) 457 freeclusterchain(pmp, chaintofree); 458 459 return (allerror); 460 } 461 462 /* 463 * Extend the file described by dep to length specified by length. 464 */ 465 int 466 deextend(dep, length, cred) 467 struct denode *dep; 468 u_long length; 469 struct ucred *cred; 470 { 471 struct msdosfsmount *pmp = dep->de_pmp; 472 u_long count; 473 int error; 474 475 /* 476 * The root of a DOS filesystem cannot be extended. 477 */ 478 if ((DETOV(dep)->v_vflag & VV_ROOT) && !FAT32(pmp)) 479 return (EINVAL); 480 481 /* 482 * Directories cannot be extended. 483 */ 484 if (dep->de_Attributes & ATTR_DIRECTORY) 485 return (EISDIR); 486 487 if (length <= dep->de_FileSize) 488 panic("deextend: file too large"); 489 490 /* 491 * Compute the number of clusters to allocate. 492 */ 493 count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize); 494 if (count > 0) { 495 if (count > pmp->pm_freeclustercount) 496 return (ENOSPC); 497 error = extendfile(dep, count, NULL, NULL, DE_CLEAR); 498 if (error) { 499 /* truncate the added clusters away again */ 500 (void) detrunc(dep, dep->de_FileSize, 0, cred, NULL); 501 return (error); 502 } 503 } 504 dep->de_FileSize = length; 505 dep->de_flag |= DE_UPDATE | DE_MODIFIED; 506 return (deupdat(dep, !(DETOV(dep)->v_mount->mnt_flag & MNT_ASYNC))); 507 } 508 509 /* 510 * Move a denode to its correct hash queue after the file it represents has 511 * been moved to a new directory. 512 */ 513 void 514 reinsert(dep) 515 struct denode *dep; 516 { 517 struct vnode *vp; 518 519 /* 520 * Fix up the denode cache. If the denode is for a directory, 521 * there is nothing to do since the hash is based on the starting 522 * cluster of the directory file and that hasn't changed. If for a 523 * file the hash is based on the location of the directory entry, 524 * so we must remove it from the cache and re-enter it with the 525 * hash based on the new location of the directory entry. 526 */ 527 #if 0 528 if (dep->de_Attributes & ATTR_DIRECTORY) 529 return; 530 #endif 531 vp = DETOV(dep); 532 dep->de_inode = (uint64_t)dep->de_pmp->pm_bpcluster * dep->de_dirclust + 533 dep->de_diroffset; 534 vfs_hash_rehash(vp, dep->de_inode); 535 } 536 537 int 538 msdosfs_reclaim(ap) 539 struct vop_reclaim_args /* { 540 struct vnode *a_vp; 541 } */ *ap; 542 { 543 struct vnode *vp = ap->a_vp; 544 struct denode *dep = VTODE(vp); 545 546 #ifdef MSDOSFS_DEBUG 547 printf("msdosfs_reclaim(): dep %p, file %s, refcnt %ld\n", 548 dep, dep->de_Name, dep->de_refcnt); 549 #endif 550 551 /* 552 * Destroy the vm object and flush associated pages. 553 */ 554 vnode_destroy_vobject(vp); 555 /* 556 * Remove the denode from its hash chain. 557 */ 558 vfs_hash_remove(vp); 559 /* 560 * Purge old data structures associated with the denode. 561 */ 562 #if 0 /* XXX */ 563 dep->de_flag = 0; 564 #endif 565 free(dep, M_MSDOSFSNODE); 566 vp->v_data = NULL; 567 568 return (0); 569 } 570 571 int 572 msdosfs_inactive(ap) 573 struct vop_inactive_args /* { 574 struct vnode *a_vp; 575 struct thread *a_td; 576 } */ *ap; 577 { 578 struct vnode *vp = ap->a_vp; 579 struct denode *dep = VTODE(vp); 580 struct thread *td = ap->a_td; 581 int error = 0; 582 583 #ifdef MSDOSFS_DEBUG 584 printf("msdosfs_inactive(): dep %p, de_Name[0] %x\n", dep, dep->de_Name[0]); 585 #endif 586 587 /* 588 * Ignore denodes related to stale file handles. 589 */ 590 if (dep->de_Name[0] == SLOT_DELETED || dep->de_Name[0] == SLOT_EMPTY) 591 goto out; 592 593 /* 594 * If the file has been deleted and it is on a read/write 595 * filesystem, then truncate the file, and mark the directory slot 596 * as empty. (This may not be necessary for the dos filesystem.) 597 */ 598 #ifdef MSDOSFS_DEBUG 599 printf("msdosfs_inactive(): dep %p, refcnt %ld, mntflag %x, MNT_RDONLY %x\n", 600 dep, dep->de_refcnt, vp->v_mount->mnt_flag, MNT_RDONLY); 601 #endif 602 if (dep->de_refcnt <= 0 && (vp->v_mount->mnt_flag & MNT_RDONLY) == 0) { 603 error = detrunc(dep, (u_long) 0, 0, NOCRED, td); 604 dep->de_flag |= DE_UPDATE; 605 dep->de_Name[0] = SLOT_DELETED; 606 } 607 deupdat(dep, 0); 608 609 out: 610 /* 611 * If we are done with the denode, reclaim it 612 * so that it can be reused immediately. 613 */ 614 #ifdef MSDOSFS_DEBUG 615 printf("msdosfs_inactive(): v_usecount %d, de_Name[0] %x\n", 616 vrefcnt(vp), dep->de_Name[0]); 617 #endif 618 if (dep->de_Name[0] == SLOT_DELETED || dep->de_Name[0] == SLOT_EMPTY) 619 vrecycle(vp, td); 620 return (error); 621 }
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