xref: /dragonfly/sys/vfs/msdosfs/msdosfs_denode.c (revision 521a7b05)
1 /* $FreeBSD: src/sys/msdosfs/msdosfs_denode.c,v 1.47.2.3 2002/08/22 16:20:15 trhodes Exp $ */
2 /* $DragonFly: src/sys/vfs/msdosfs/msdosfs_denode.c,v 1.28 2007/05/06 19:23:34 dillon Exp $ */
3 /*	$NetBSD: msdosfs_denode.c,v 1.28 1998/02/10 14:10:00 mrg Exp $	*/
4 
5 /*-
6  * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
7  * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
8  * All rights reserved.
9  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by TooLs GmbH.
22  * 4. The name of TooLs GmbH may not be used to endorse or promote products
23  *    derived from this software without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
29  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
30  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
31  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
32  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
33  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
34  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35  */
36 /*
37  * Written by Paul Popelka (paulp@uts.amdahl.com)
38  *
39  * You can do anything you want with this software, just don't say you wrote
40  * it, and don't remove this notice.
41  *
42  * This software is provided "as is".
43  *
44  * The author supplies this software to be publicly redistributed on the
45  * understanding that the author is not responsible for the correct
46  * functioning of this software in any circumstances and is not liable for
47  * any damages caused by this software.
48  *
49  * October 1992
50  */
51 
52 #include <sys/param.h>
53 #include <sys/systm.h>
54 #include <sys/kernel.h>
55 #include <sys/mount.h>
56 #include <sys/malloc.h>
57 #include <sys/proc.h>
58 #include <sys/buf.h>
59 #include <sys/vnode.h>
60 
61 #include <vm/vm.h>
62 #include <vm/vm_extern.h>
63 
64 #include "bpb.h"
65 #include "msdosfsmount.h"
66 #include "direntry.h"
67 #include "denode.h"
68 #include "fat.h"
69 
70 static int msdosfs_hashins (struct denode *dep);
71 static void msdosfs_hashrem (struct denode *dep);
72 
73 static MALLOC_DEFINE(M_MSDOSFSNODE, "MSDOSFS node", "MSDOSFS vnode private part");
74 
75 static struct denode **dehashtbl;
76 static u_long dehash;			/* size of hash table - 1 */
77 #define	DEHASH(dev, dcl, doff)	(dehashtbl[(minor(dev) + (dcl) + (doff) / 	\
78 				sizeof(struct direntry)) & dehash])
79 static struct lwkt_token dehash_token;
80 
81 union _qcvt {
82 	quad_t qcvt;
83 	long val[2];
84 };
85 #define SETHIGH(q, h) { \
86 	union _qcvt tmp; \
87 	tmp.qcvt = (q); \
88 	tmp.val[_QUAD_HIGHWORD] = (h); \
89 	(q) = tmp.qcvt; \
90 }
91 #define SETLOW(q, l) { \
92 	union _qcvt tmp; \
93 	tmp.qcvt = (q); \
94 	tmp.val[_QUAD_LOWWORD] = (l); \
95 	(q) = tmp.qcvt; \
96 }
97 
98 static struct denode *
99 		msdosfs_hashget (cdev_t dev, u_long dirclust, u_long diroff);
100 
101 /*ARGSUSED*/
102 int
103 msdosfs_init(struct vfsconf *vfsp)
104 {
105 	dehash = 16;
106 	while (dehash < desiredvnodes)
107 		dehash <<= 1;
108 	dehashtbl = kmalloc(sizeof(void *) * dehash, M_MSDOSFSMNT,
109 			   M_WAITOK|M_ZERO);
110 	--dehash;
111 	lwkt_token_init(&dehash_token);
112 	return (0);
113 }
114 
115 int
116 msdosfs_uninit(struct vfsconf *vfsp)
117 {
118 
119 	if (dehashtbl)
120 		kfree(dehashtbl, M_MSDOSFSMNT);
121 	return (0);
122 }
123 
124 static struct denode *
125 msdosfs_hashget(cdev_t dev, u_long dirclust, u_long diroff)
126 {
127 	struct denode *dep;
128 	lwkt_tokref ilock;
129 	struct vnode *vp;
130 
131 	lwkt_gettoken(&ilock, &dehash_token);
132 loop:
133 	for (dep = DEHASH(dev, dirclust, diroff); dep; dep = dep->de_next) {
134 		if (dirclust != dep->de_dirclust
135 		    || diroff != dep->de_diroffset
136 		    || dev != dep->de_dev
137 		    || dep->de_refcnt == 0) {
138 			continue;
139 		}
140 		vp = DETOV(dep);
141 		if (vget(vp, LK_EXCLUSIVE))
142 			goto loop;
143 
144 		/*
145 		 * We must check to see if the inode has been ripped
146 		 * out from under us after blocking.
147 		 */
148 		for (dep = DEHASH(dev, dirclust, diroff); dep; dep = dep->de_next) {
149 			if (dirclust == dep->de_dirclust
150 			    && diroff == dep->de_diroffset
151 			    && dev == dep->de_dev
152 			    && dep->de_refcnt != 0) {
153 				break;
154 			}
155 		}
156 		if (dep == NULL || DETOV(dep) != vp) {
157 			vput(vp);
158 			goto loop;
159 		}
160 		lwkt_reltoken(&ilock);
161 		return (dep);
162 	}
163 	lwkt_reltoken(&ilock);
164 	return (NULL);
165 }
166 
167 static
168 int
169 msdosfs_hashins(struct denode *dep)
170 {
171 	struct denode **depp, *deq;
172 	lwkt_tokref ilock;
173 
174 	lwkt_gettoken(&ilock, &dehash_token);
175 	depp = &DEHASH(dep->de_dev, dep->de_dirclust, dep->de_diroffset);
176 	while ((deq = *depp) != NULL) {
177 		if (deq->de_dev == dep->de_dev &&
178 		    deq->de_dirclust == dep->de_dirclust &&
179 		    deq->de_diroffset == dep->de_diroffset) {
180 			lwkt_reltoken(&ilock);
181 			return(EBUSY);
182 		}
183 		depp = &deq->de_next;
184 	}
185 	dep->de_next = NULL;
186 	*depp = dep;
187 	lwkt_reltoken(&ilock);
188 	return(0);
189 }
190 
191 static
192 void
193 msdosfs_hashrem(struct denode *dep)
194 {
195 	struct denode **depp, *deq;
196 	lwkt_tokref ilock;
197 
198 	lwkt_gettoken(&ilock, &dehash_token);
199 	depp = &DEHASH(dep->de_dev, dep->de_dirclust, dep->de_diroffset);
200 	while ((deq = *depp) != NULL) {
201 		if (dep == deq)
202 			break;
203 		depp = &deq->de_next;
204 	}
205 	KKASSERT(dep == deq);
206 	*depp = dep->de_next;
207 	dep->de_next = NULL;
208 	lwkt_reltoken(&ilock);
209 }
210 
211 void
212 msdosfs_reinsert(struct denode *ip, u_long new_dirclust, u_long new_diroffset)
213 {
214 	lwkt_tokref ilock;
215 
216 	lwkt_gettoken(&ilock, &dehash_token);
217 	msdosfs_hashrem(ip);
218 	ip->de_dirclust = new_dirclust;
219 	ip->de_diroffset = new_diroffset;
220 	msdosfs_hashins(ip);
221 	lwkt_reltoken(&ilock);
222 }
223 
224 /*
225  * If deget() succeeds it returns with the gotten denode locked().
226  *
227  * pmp	     - address of msdosfsmount structure of the filesystem containing
228  *	       the denode of interest.  The pm_dev field and the address of
229  *	       the msdosfsmount structure are used.
230  * dirclust  - which cluster bp contains, if dirclust is 0 (root directory)
231  *	       diroffset is relative to the beginning of the root directory,
232  *	       otherwise it is cluster relative.
233  * diroffset - offset past begin of cluster of denode we want
234  * depp	     - returns the address of the gotten denode.
235  */
236 int
237 deget(struct msdosfsmount *pmp,	/* so we know the maj/min number */
238       u_long dirclust,		/* cluster this dir entry came from */
239       u_long diroffset,		/* index of entry within the cluster */
240       struct denode **depp)	/* returns the addr of the gotten denode */
241 {
242 	int error;
243 	cdev_t dev = pmp->pm_dev;
244 	struct mount *mntp = pmp->pm_mountp;
245 	struct direntry *direntptr;
246 	struct denode *ldep;
247 	struct vnode *nvp;
248 	struct buf *bp;
249 	struct timeval tv;
250 
251 #ifdef MSDOSFS_DEBUG
252 	kprintf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n",
253 	    pmp, dirclust, diroffset, depp);
254 #endif
255 
256 	/*
257 	 * On FAT32 filesystems, root is a (more or less) normal
258 	 * directory
259 	 */
260 	if (FAT32(pmp) && dirclust == MSDOSFSROOT)
261 		dirclust = pmp->pm_rootdirblk;
262 
263 again:
264 	/*
265 	 * See if the denode is in the denode cache. Use the location of
266 	 * the directory entry to compute the hash value. For subdir use
267 	 * address of "." entry. For root dir (if not FAT32) use cluster
268 	 * MSDOSFSROOT, offset MSDOSFSROOT_OFS
269 	 *
270 	 * NOTE: The check for de_refcnt > 0 below insures the denode being
271 	 * examined does not represent an unlinked but still open file.
272 	 * These files are not to be accessible even when the directory
273 	 * entry that represented the file happens to be reused while the
274 	 * deleted file is still open.
275 	 */
276 	ldep = msdosfs_hashget(dev, dirclust, diroffset);
277 	if (ldep) {
278 		*depp = ldep;
279 		return (0);
280 	}
281 
282 	/*
283 	 * Do the MALLOC before the getnewvnode since doing so afterward
284 	 * might cause a bogus v_data pointer to get dereferenced
285 	 * elsewhere if MALLOC should block.
286 	 */
287 	MALLOC(ldep, struct denode *, sizeof(struct denode), M_MSDOSFSNODE, M_WAITOK);
288 
289 	/*
290 	 * Directory entry was not in cache, have to create a vnode and
291 	 * copy it from the passed disk buffer.
292 	 */
293 
294 	/* getnewvnode() does a vref() on the vnode */
295 	error = getnewvnode(VT_MSDOSFS, mntp, &nvp, VLKTIMEOUT, 0);
296 	if (error) {
297 		*depp = NULL;
298 		FREE(ldep, M_MSDOSFSNODE);
299 		return error;
300 	}
301 
302 	bzero((caddr_t)ldep, sizeof *ldep);
303 	ldep->de_vnode = nvp;
304 	ldep->de_flag = 0;
305 	ldep->de_devvp = 0;
306 	ldep->de_dev = dev;
307 	ldep->de_dirclust = dirclust;
308 	ldep->de_diroffset = diroffset;
309 	fc_purge(ldep, 0);	/* init the fat cache for this denode */
310 
311 	/*
312 	 * Insert the denode into the hash queue.  If a collision occurs
313 	 * throw away the vnode and try again.
314 	 */
315 	if (msdosfs_hashins(ldep) != 0) {
316 		kprintf("debug: msdosfs: hashins collision, retrying\n");
317 		vx_put(nvp);
318 		kfree(ldep, M_MSDOSFSNODE);
319 		goto again;
320 	}
321 	nvp->v_data = ldep;
322 	ldep->de_pmp = pmp;
323 	ldep->de_refcnt = 1;
324 	/*
325 	 * Copy the directory entry into the denode area of the vnode.
326 	 */
327 	if ((dirclust == MSDOSFSROOT
328 	     || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk))
329 	    && diroffset == MSDOSFSROOT_OFS) {
330 		/*
331 		 * Directory entry for the root directory. There isn't one,
332 		 * so we manufacture one. We should probably rummage
333 		 * through the root directory and find a label entry (if it
334 		 * exists), and then use the time and date from that entry
335 		 * as the time and date for the root denode.
336 		 */
337 		nvp->v_flag |= VROOT; /* should be further down		XXX */
338 
339 		ldep->de_Attributes = ATTR_DIRECTORY;
340 		ldep->de_LowerCase = 0;
341 		if (FAT32(pmp))
342 			ldep->de_StartCluster = pmp->pm_rootdirblk;
343 			/* de_FileSize will be filled in further down */
344 		else {
345 			ldep->de_StartCluster = MSDOSFSROOT;
346 			ldep->de_FileSize = pmp->pm_rootdirsize * DEV_BSIZE;
347 		}
348 		/*
349 		 * fill in time and date so that dos2unixtime() doesn't
350 		 * spit up when called from msdosfs_getattr() with root
351 		 * denode
352 		 */
353 		ldep->de_CHun = 0;
354 		ldep->de_CTime = 0x0000;	/* 00:00:00	 */
355 		ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT)
356 		    | (1 << DD_DAY_SHIFT);
357 		/* Jan 1, 1980	 */
358 		ldep->de_ADate = ldep->de_CDate;
359 		ldep->de_MTime = ldep->de_CTime;
360 		ldep->de_MDate = ldep->de_CDate;
361 		/* leave the other fields as garbage */
362 	} else {
363 		error = readep(pmp, dirclust, diroffset, &bp, &direntptr);
364 		if (error) {
365 			/*
366 			 * The denode does not contain anything useful, so
367 			 * it would be wrong to leave it on its hash chain.
368 			 * Arrange for vput() to just forget about it.
369 			 */
370 			ldep->de_Name[0] = SLOT_DELETED;
371 
372 			vx_put(nvp);
373 			*depp = NULL;
374 			return (error);
375 		}
376 		DE_INTERNALIZE(ldep, direntptr);
377 		brelse(bp);
378 	}
379 
380 	/*
381 	 * Fill in a few fields of the vnode and finish filling in the
382 	 * denode.  Then return the address of the found denode.
383 	 */
384 	if (ldep->de_Attributes & ATTR_DIRECTORY) {
385 		/*
386 		 * Since DOS directory entries that describe directories
387 		 * have 0 in the filesize field, we take this opportunity
388 		 * to find out the length of the directory and plug it into
389 		 * the denode structure.
390 		 */
391 		u_long size;
392 
393 		/*
394 		 * XXX Sometimes, these arrives that . entry have cluster
395 		 * number 0, when it shouldn't.  Use real cluster number
396 		 * instead of what is written in directory entry.
397 		 */
398 		if ((diroffset == 0) && (ldep->de_StartCluster != dirclust)) {
399 			kprintf("deget(): . entry at clust %ld != %ld\n",
400 					dirclust, ldep->de_StartCluster);
401 			ldep->de_StartCluster = dirclust;
402 		}
403 
404 		nvp->v_type = VDIR;
405 		if (ldep->de_StartCluster != MSDOSFSROOT) {
406 			error = pcbmap(ldep, 0xffff, NULL, &size, NULL);
407 			if (error == E2BIG) {
408 				ldep->de_FileSize = de_cn2off(pmp, size);
409 				error = 0;
410 			} else
411 				kprintf("deget(): pcbmap returned %d\n", error);
412 		}
413 	} else {
414 		nvp->v_type = VREG;
415 	}
416 	getmicrouptime(&tv);
417 	SETHIGH(ldep->de_modrev, tv.tv_sec);
418 	SETLOW(ldep->de_modrev, tv.tv_usec * 4294);
419 	ldep->de_devvp = pmp->pm_devvp;
420 	vref(ldep->de_devvp);
421 	vinitvmio(nvp, ldep->de_FileSize);
422 	/*
423 	 * Leave nvp locked and refd so the returned inode is effectively
424 	 * locked and refd.
425 	 */
426 	*depp = ldep;
427 	return (0);
428 }
429 
430 int
431 deupdat(struct denode *dep, int waitfor)
432 {
433 	int error;
434 	struct buf *bp;
435 	struct direntry *dirp;
436 	struct timespec ts;
437 
438 	if (DETOV(dep)->v_mount->mnt_flag & MNT_RDONLY)
439 		return (0);
440 	getnanotime(&ts);
441 	DETIMES(dep, &ts, &ts, &ts);
442 	if ((dep->de_flag & DE_MODIFIED) == 0)
443 		return (0);
444 	dep->de_flag &= ~DE_MODIFIED;
445 	if (dep->de_Attributes & ATTR_DIRECTORY)
446 		return (0);
447 	if (dep->de_refcnt <= 0)
448 		return (0);
449 	error = readde(dep, &bp, &dirp);
450 	if (error)
451 		return (error);
452 	DE_EXTERNALIZE(dirp, dep);
453 	if (waitfor)
454 		return (bwrite(bp));
455 	else {
456 		bdwrite(bp);
457 		return (0);
458 	}
459 }
460 
461 /*
462  * Truncate the file described by dep to the length specified by length.
463  */
464 int
465 detrunc(struct denode *dep, u_long length, int flags)
466 {
467 	int error;
468 	int allerror;
469 	u_long eofentry;
470 	u_long chaintofree;
471 	daddr_t bn, cn;
472 	int boff;
473 	int isadir = dep->de_Attributes & ATTR_DIRECTORY;
474 	struct buf *bp;
475 	struct msdosfsmount *pmp = dep->de_pmp;
476 
477 #ifdef MSDOSFS_DEBUG
478 	kprintf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags);
479 #endif
480 
481 	/*
482 	 * Disallow attempts to truncate the root directory since it is of
483 	 * fixed size.  That's just the way dos filesystems are.  We use
484 	 * the VROOT bit in the vnode because checking for the directory
485 	 * bit and a startcluster of 0 in the denode is not adequate to
486 	 * recognize the root directory at this point in a file or
487 	 * directory's life.
488 	 */
489 	if ((DETOV(dep)->v_flag & VROOT) && !FAT32(pmp)) {
490 		kprintf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n",
491 		    dep->de_dirclust, dep->de_diroffset);
492 		return (EINVAL);
493 	}
494 
495 
496 	if (dep->de_FileSize < length) {
497 		vnode_pager_setsize(DETOV(dep), length);
498 		return deextend(dep, length);
499 	}
500 
501 	/*
502 	 * If the desired length is 0 then remember the starting cluster of
503 	 * the file and set the StartCluster field in the directory entry
504 	 * to 0.  If the desired length is not zero, then get the number of
505 	 * the last cluster in the shortened file.  Then get the number of
506 	 * the first cluster in the part of the file that is to be freed.
507 	 * Then set the next cluster pointer in the last cluster of the
508 	 * file to CLUST_EOFE.
509 	 */
510 	if (length == 0) {
511 		chaintofree = dep->de_StartCluster;
512 		dep->de_StartCluster = 0;
513 		eofentry = ~0;
514 	} else {
515 		error = pcbmap(dep, de_clcount(pmp, length) - 1,
516 			       NULL, &eofentry, NULL);
517 		if (error) {
518 #ifdef MSDOSFS_DEBUG
519 			kprintf("detrunc(): pcbmap fails %d\n", error);
520 #endif
521 			return (error);
522 		}
523 	}
524 
525 	fc_purge(dep, de_clcount(pmp, length));
526 
527 	/*
528 	 * If the new length is not a multiple of the cluster size then we
529 	 * must zero the tail end of the new last cluster in case it
530 	 * becomes part of the file again because of a seek.
531 	 */
532 	if ((boff = length & pmp->pm_crbomask) != 0) {
533 		if (isadir) {
534 			bn = xcntobn(pmp, eofentry);
535 			error = bread(pmp->pm_devvp, de_bntodoff(pmp, bn), pmp->pm_bpcluster, &bp);
536 		} else {
537 			cn = de_cluster(pmp, length);
538 			error = bread(DETOV(dep), de_cn2doff(pmp, cn), pmp->pm_bpcluster, &bp);
539 		}
540 		if (error) {
541 			brelse(bp);
542 #ifdef MSDOSFS_DEBUG
543 			kprintf("detrunc(): bread fails %d\n", error);
544 #endif
545 			return (error);
546 		}
547 		/*
548 		 * is this the right place for it?
549 		 */
550 		bzero(bp->b_data + boff, pmp->pm_bpcluster - boff);
551 		if (flags & IO_SYNC)
552 			bwrite(bp);
553 		else
554 			bdwrite(bp);
555 	}
556 
557 	/*
558 	 * Write out the updated directory entry.  Even if the update fails
559 	 * we free the trailing clusters.
560 	 */
561 	dep->de_FileSize = length;
562 	if (!isadir)
563 		dep->de_flag |= DE_UPDATE|DE_MODIFIED;
564 	allerror = vtruncbuf(DETOV(dep), length, pmp->pm_bpcluster);
565 #ifdef MSDOSFS_DEBUG
566 	if (allerror)
567 		kprintf("detrunc(): vtruncbuf error %d\n", allerror);
568 #endif
569 	error = deupdat(dep, 1);
570 	if (error && (allerror == 0))
571 		allerror = error;
572 #ifdef MSDOSFS_DEBUG
573 	kprintf("detrunc(): allerror %d, eofentry %lu\n",
574 	       allerror, eofentry);
575 #endif
576 
577 	/*
578 	 * If we need to break the cluster chain for the file then do it
579 	 * now.
580 	 */
581 	if (eofentry != ~0) {
582 		error = fatentry(FAT_GET_AND_SET, pmp, eofentry,
583 				 &chaintofree, CLUST_EOFE);
584 		if (error) {
585 #ifdef MSDOSFS_DEBUG
586 			kprintf("detrunc(): fatentry errors %d\n", error);
587 #endif
588 			return (error);
589 		}
590 		fc_setcache(dep, FC_LASTFC, de_cluster(pmp, length - 1),
591 			    eofentry);
592 	}
593 
594 	/*
595 	 * Now free the clusters removed from the file because of the
596 	 * truncation.
597 	 */
598 	if (chaintofree != 0 && !MSDOSFSEOF(pmp, chaintofree))
599 		freeclusterchain(pmp, chaintofree);
600 
601 	return (allerror);
602 }
603 
604 /*
605  * Extend the file described by dep to length specified by length.
606  */
607 int
608 deextend(struct denode *dep, u_long length)
609 {
610 	struct msdosfsmount *pmp = dep->de_pmp;
611 	u_long count;
612 	int error;
613 
614 	/*
615 	 * The root of a DOS filesystem cannot be extended.
616 	 */
617 	if ((DETOV(dep)->v_flag & VROOT) && !FAT32(pmp))
618 		return (EINVAL);
619 
620 	/*
621 	 * Directories cannot be extended.
622 	 */
623 	if (dep->de_Attributes & ATTR_DIRECTORY)
624 		return (EISDIR);
625 
626 	if (length <= dep->de_FileSize)
627 		panic("deextend: file too large");
628 
629 	/*
630 	 * Compute the number of clusters to allocate.
631 	 */
632 	count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize);
633 	if (count > 0) {
634 		if (count > pmp->pm_freeclustercount)
635 			return (ENOSPC);
636 		error = extendfile(dep, count, NULL, NULL, DE_CLEAR);
637 		if (error) {
638 			/* truncate the added clusters away again */
639 			detrunc(dep, dep->de_FileSize, 0);
640 			return (error);
641 		}
642 	}
643 	dep->de_FileSize = length;
644 	dep->de_flag |= DE_UPDATE|DE_MODIFIED;
645 	return (deupdat(dep, 1));
646 }
647 
648 /*
649  * msdosfs_reclaim(struct vnode *a_vp)
650  */
651 int
652 msdosfs_reclaim(struct vop_reclaim_args *ap)
653 {
654 	struct vnode *vp = ap->a_vp;
655 	struct denode *dep = VTODE(vp);
656 
657 #ifdef MSDOSFS_DEBUG
658 	kprintf("msdosfs_reclaim(): dep %p, file %s, refcnt %ld\n",
659 	    dep, dep ? dep->de_Name : "?", dep ? dep->de_refcnt : -1);
660 #endif
661 
662 	if (prtactive && vp->v_sysref.refcnt > 1)
663 		vprint("msdosfs_reclaim(): pushing active", vp);
664 	/*
665 	 * Remove the denode from its hash chain.
666 	 */
667 	vp->v_data = NULL;
668 	if (dep) {
669 		msdosfs_hashrem(dep);
670 		if (dep->de_devvp) {
671 			vrele(dep->de_devvp);
672 			dep->de_devvp = 0;
673 		}
674 		kfree(dep, M_MSDOSFSNODE);
675 	}
676 	return (0);
677 }
678 
679 /*
680  * msdosfs_inactive(struct vnode *a_vp, struct thread *a_td)
681  */
682 int
683 msdosfs_inactive(struct vop_inactive_args *ap)
684 {
685 	struct vnode *vp = ap->a_vp;
686 	struct denode *dep = VTODE(vp);
687 	int error = 0;
688 
689 #ifdef MSDOSFS_DEBUG
690 	kprintf("msdosfs_inactive(): dep %p, de_Name[0] %x\n", dep, dep->de_Name[0]);
691 #endif
692 
693 	if (prtactive && vp->v_sysref.refcnt > 1)
694 		vprint("msdosfs_inactive(): pushing active", vp);
695 
696 	/*
697 	 * Ignore denodes related to stale file handles.
698 	 */
699 	if (dep->de_Name[0] == SLOT_DELETED)
700 		goto out;
701 
702 	/*
703 	 * If the file has been deleted and it is on a read/write
704 	 * filesystem, then truncate the file, and mark the directory slot
705 	 * as empty.  (This may not be necessary for the dos filesystem.)
706 	 */
707 #ifdef MSDOSFS_DEBUG
708 	kprintf("msdosfs_inactive(): dep %p, refcnt %ld, mntflag %x, MNT_RDONLY %x\n",
709 	       dep, dep->de_refcnt, vp->v_mount->mnt_flag, MNT_RDONLY);
710 #endif
711 	if (dep->de_refcnt <= 0 && (vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
712 		error = detrunc(dep, (u_long) 0, 0);
713 		dep->de_flag |= DE_UPDATE;
714 		dep->de_Name[0] = SLOT_DELETED;
715 	}
716 	deupdat(dep, 0);
717 
718 out:
719 	/*
720 	 * If we are done with the denode, reclaim it
721 	 * so that it can be reused immediately.
722 	 */
723 #ifdef MSDOSFS_DEBUG
724 	kprintf("msdosfs_inactive(): v_sysrefs %d, de_Name[0] %x\n",
725 		vp->v_sysref.refcnt, dep->de_Name[0]);
726 #endif
727 	if (dep->de_Name[0] == SLOT_DELETED)
728 		vrecycle(vp);
729 	return (error);
730 }
731