Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.sbin/makefs/msdos/msdosfs_denode.c	Lines:	0	107	0.0 %
Date:	2017-11-13	Branches:	0	60	0.0 %


/*	$OpenBSD: msdosfs_denode.c,v 1.6 2016/10/22 22:20:24 natano Exp $	*/
/*	$NetBSD: msdosfs_denode.c,v 1.7 2015/03/29 05:52:59 agc Exp $	*/

/*-
 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
 * All rights reserved.
 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by TooLs GmbH.
 * 4. The name of TooLs GmbH may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 * Written by Paul Popelka (paulp@uts.amdahl.com)
 *
 * You can do anything you want with this software, just don't say you wrote
 * it, and don't remove this notice.
 *
 * This software is provided "as is".
 *
 * The author supplies this software to be publicly redistributed on the
 * understanding that the author is not responsible for the correct
 * functioning of this software in any circumstances and is not liable for
 * any damages caused by this software.
 *
 * October 1992
 */

#include <sys/param.h>

#include "ffs/buf.h"

#include <msdosfs/bpb.h>
#include "msdos/msdosfsmount.h"
#include "msdos/direntry.h"
#include "msdos/denode.h"
#include "msdos/fat.h"

#include <util.h>

#include "makefs.h"

/*
 * If deget() succeeds it returns with the gotten denode locked().
 *
 * pmp	     - address of msdosfsmount structure of the filesystem containing
 *	       the denode of interest.  The pm_dev field and the address of
 *	       the msdosfsmount structure are used.
 * dirclust  - which cluster bp contains, if dirclust is 0 (root directory)
 *	       diroffset is relative to the beginning of the root directory,
 *	       otherwise it is cluster relative.
 * diroffset - offset past begin of cluster of denode we want
 * depp	     - returns the address of the gotten denode.
 */
int
deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset,
    struct denode **depp)
	/* pmp:	 so we know the maj/min number */
	/* dirclust:		 cluster this dir entry came from */
	/* diroffset:		 index of entry within the cluster */
	/* depp:		 returns the addr of the gotten denode */
{
	int error;
	struct direntry *direntptr;
	struct denode *ldep;
	struct mkfsbuf *bp;

#ifdef MSDOSFS_DEBUG
	printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n",
	    pmp, dirclust, diroffset, depp);
#endif

	/*
	 * On FAT32 filesystems, root is a (more or less) normal
	 * directory
	 */
	if (FAT32(pmp) && dirclust == MSDOSFSROOT)
		dirclust = pmp->pm_rootdirblk;

	ldep = ecalloc(1, sizeof(*ldep));
	ldep->de_mkfsvnode = NULL;
	ldep->de_flag = 0;
	ldep->de_devvp = 0;
	ldep->de_lockf = 0;
	ldep->de_dev = pmp->pm_dev;
	ldep->de_dirclust = dirclust;
	ldep->de_diroffset = diroffset;
	ldep->de_pmp = pmp;
	ldep->de_devvp = pmp->pm_devvp;
	ldep->de_refcnt = 1;
	fc_purge(ldep, 0);
	/*
	 * Copy the directory entry into the denode area of the mkfsvnode.
	 */
	if ((dirclust == MSDOSFSROOT
	     || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk))
	    && diroffset == MSDOSFSROOT_OFS) {
		/*
		 * Directory entry for the root directory. There isn't one,
		 * so we manufacture one. We should probably rummage
		 * through the root directory and find a label entry (if it
		 * exists), and then use the time and date from that entry
		 * as the time and date for the root denode.
		 */
		ldep->de_mkfsvnode = (struct mkfsvnode *)-1;

		ldep->de_Attributes = ATTR_DIRECTORY;
		if (FAT32(pmp))
			ldep->de_StartCluster = pmp->pm_rootdirblk;
			/* de_FileSize will be filled in further down */
		else {
			ldep->de_StartCluster = MSDOSFSROOT;
			ldep->de_FileSize = pmp->pm_rootdirsize * pmp->pm_BytesPerSec;
		}
		/*
		 * fill in time and date so that dos2unixtime() doesn't
		 * spit up when called from msdosfs_getattr() with root
		 * denode
		 */
		ldep->de_CHun = 0;
		ldep->de_CTime = 0x0000;	/* 00:00:00	 */
		ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT)
		    | (1 << DD_DAY_SHIFT);
		/* Jan 1, 1980	 */
		ldep->de_ADate = ldep->de_CDate;
		ldep->de_MTime = ldep->de_CTime;
		ldep->de_MDate = ldep->de_CDate;
		/* leave the other fields as garbage */
	} else {
		error = readep(pmp, dirclust, diroffset, &bp, &direntptr);
		if (error) {
			ldep->de_devvp = NULL;
			ldep->de_Name[0] = SLOT_DELETED;
			return (error);
		}
		DE_INTERNALIZE(ldep, direntptr);
		brelse(bp, 0);
	}

	/*
	 * Fill in a few fields of the mkfsvnode and finish filling in the
	 * denode.  Then return the address of the found denode.
	 */
	if (ldep->de_Attributes & ATTR_DIRECTORY) {
		/*
		 * Since DOS directory entries that describe directories
		 * have 0 in the filesize field, we take this opportunity
		 * to find out the length of the directory and plug it into
		 * the denode structure.
		 */
		u_long size;

		if (ldep->de_StartCluster != MSDOSFSROOT) {
			error = pcbmap(ldep, CLUST_END, 0, &size, 0);
			if (error == E2BIG) {
				ldep->de_FileSize = de_cn2off(pmp, size);
				error = 0;
			} else
				printf("deget(): pcbmap returned %d\n", error);
		}
	}
	*depp = ldep;
	return (0);
}

/*
 * Truncate the file described by dep to the length specified by length.
 */
int
detrunc(struct denode *dep, u_long length, int flags)
{
	int error;
	int allerror = 0;
	u_long eofentry;
	u_long chaintofree = 0;
	daddr_t bn, lastblock;
	int boff;
	int isadir = dep->de_Attributes & ATTR_DIRECTORY;
	struct mkfsbuf *bp;
	struct msdosfsmount *pmp = dep->de_pmp;

#ifdef MSDOSFS_DEBUG
	printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags);
#endif

	/*
	 * Disallow attempts to truncate the root directory since it is of
	 * fixed size.  That's just the way dos filesystems are.  We use
	 * the VROOT bit in the mkfsvnode because checking for the directory
	 * bit and a startcluster of 0 in the denode is not adequate to
	 * recognize the root directory at this point in a file or
	 * directory's life.
	 */
	if (dep->de_mkfsvnode != NULL && !FAT32(pmp)) {
		printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n",
		    dep->de_dirclust, dep->de_diroffset);
		return (EINVAL);
	}

	if (dep->de_FileSize < length)
		return (deextend(dep, length));
	lastblock = de_clcount(pmp, length) - 1;

	/*
	 * If the desired length is 0 then remember the starting cluster of
	 * the file and set the StartCluster field in the directory entry
	 * to 0.  If the desired length is not zero, then get the number of
	 * the last cluster in the shortened file.  Then get the number of
	 * the first cluster in the part of the file that is to be freed.
	 * Then set the next cluster pointer in the last cluster of the
	 * file to CLUST_EOFE.
	 */
	if (length == 0) {
		chaintofree = dep->de_StartCluster;
		dep->de_StartCluster = 0;
		eofentry = ~0;
	} else {
		error = pcbmap(dep, lastblock, 0, &eofentry, 0);
		if (error) {
#ifdef MSDOSFS_DEBUG
			printf("detrunc(): pcbmap fails %d\n", error);
#endif
			return (error);
		}
	}

	/*
	 * If the new length is not a multiple of the cluster size then we
	 * must zero the tail end of the new last cluster in case it
	 * becomes part of the file again because of a seek.
	 */
	if ((boff = length & pmp->pm_crbomask) != 0) {
		if (isadir) {
			bn = cntobn(pmp, eofentry);
			error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn),
			    pmp->pm_bpcluster, B_MODIFY, &bp);
			if (error) {
#ifdef MSDOSFS_DEBUG
				printf("detrunc(): bread fails %d\n", error);
#endif
				return (error);
			}
			memset((char *)bp->b_data + boff, 0,
			    pmp->pm_bpcluster - boff);
			if (flags & IO_SYNC)
				bwrite(bp);
			else
				bdwrite(bp);
		}
	}

	/*
	 * Write out the updated directory entry.  Even if the update fails
	 * we free the trailing clusters.
	 */
	dep->de_FileSize = length;
	if (!isadir)
		dep->de_flag |= DE_UPDATE|DE_MODIFIED;
#ifdef MSDOSFS_DEBUG
	printf("detrunc(): allerror %d, eofentry %lu\n",
	       allerror, eofentry);
#endif

	/*
	 * If we need to break the cluster chain for the file then do it
	 * now.
	 */
	if (eofentry != (u_long)~0) {
		error = fatentry(FAT_GET_AND_SET, pmp, eofentry,
				 &chaintofree, CLUST_EOFE);
		if (error) {
#ifdef MSDOSFS_DEBUG
			printf("detrunc(): fatentry errors %d\n", error);
#endif
			return (error);
		}
	}

	/*
	 * Now free the clusters removed from the file because of the
	 * truncation.
	 */
	if (chaintofree != 0 && !MSDOSFSEOF(chaintofree, pmp->pm_fatmask))
		freeclusterchain(pmp, chaintofree);

	return (allerror);
}

/*
 * Extend the file described by dep to length specified by length.
 */
int
deextend(struct denode *dep, u_long length)
{
	struct msdosfsmount *pmp = dep->de_pmp;
	u_long count;
	int error;

	/*
	 * The root of a DOS filesystem cannot be extended.
	 */
	if (dep->de_mkfsvnode != NULL && !FAT32(pmp))
		return EINVAL;

	/*
	 * Directories cannot be extended.
	 */
	if (dep->de_Attributes & ATTR_DIRECTORY)
		return EISDIR;

	if (length <= dep->de_FileSize)
		return E2BIG;

	/*
	 * Compute the number of clusters to allocate.
	 */
	count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize);
	if (count > 0) {
		if (count > pmp->pm_freeclustercount)
			return (ENOSPC);
		error = extendfile(dep, count, NULL, NULL, DE_CLEAR);
		if (error) {
			/* truncate the added clusters away again */
			(void) detrunc(dep, dep->de_FileSize, 0);
			return (error);
		}
	}

	/*
	 * Zero extend file range; ubc_zerorange() uses ubc_alloc() and a
	 * memset(); we set the write size so ubc won't read in file data that
	 * is zero'd later.
	 */
	dep->de_FileSize = length;
	dep->de_flag |= DE_UPDATE|DE_MODIFIED;
	return 0;
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: msdosfs_denode.c,v 1.6 2016/10/22 22:20:24 natano Exp $ */
2			/* $NetBSD: msdosfs_denode.c,v 1.7 2015/03/29 05:52:59 agc 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
53			#include "ffs/buf.h"
54
55			#include <msdosfs/bpb.h>
56			#include "msdos/msdosfsmount.h"
57			#include "msdos/direntry.h"
58			#include "msdos/denode.h"
59			#include "msdos/fat.h"
60
61			#include <util.h>
62
63			#include "makefs.h"
64
65			/*
66			* If deget() succeeds it returns with the gotten denode locked().
67			*
68			* pmp - address of msdosfsmount structure of the filesystem containing
69			* the denode of interest. The pm_dev field and the address of
70			* the msdosfsmount structure are used.
71			* dirclust - which cluster bp contains, if dirclust is 0 (root directory)
72			* diroffset is relative to the beginning of the root directory,
73			* otherwise it is cluster relative.
74			* diroffset - offset past begin of cluster of denode we want
75			* depp - returns the address of the gotten denode.
76			*/
77			int
78			deget(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset,
79			struct denode **depp)
80			/* pmp: so we know the maj/min number */
81			/* dirclust: cluster this dir entry came from */
82			/* diroffset: index of entry within the cluster */
83			/* depp: returns the addr of the gotten denode */
84			{
85			int error;
86			struct direntry *direntptr;
87			struct denode *ldep;
88			struct mkfsbuf *bp;
89
90			#ifdef MSDOSFS_DEBUG
91			printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n",
92			pmp, dirclust, diroffset, depp);
93			#endif
94
95			/*
96			* On FAT32 filesystems, root is a (more or less) normal
97			* directory
98			*/
99			if (FAT32(pmp) && dirclust == MSDOSFSROOT)
100			dirclust = pmp->pm_rootdirblk;
101
102			ldep = ecalloc(1, sizeof(*ldep));
103			ldep->de_mkfsvnode = NULL;
104			ldep->de_flag = 0;
105			ldep->de_devvp = 0;
106			ldep->de_lockf = 0;
107			ldep->de_dev = pmp->pm_dev;
108			ldep->de_dirclust = dirclust;
109			ldep->de_diroffset = diroffset;
110			ldep->de_pmp = pmp;
111			ldep->de_devvp = pmp->pm_devvp;
112			ldep->de_refcnt = 1;
113			fc_purge(ldep, 0);
114			/*
115			* Copy the directory entry into the denode area of the mkfsvnode.
116			*/
117			if ((dirclust == MSDOSFSROOT
118			\|\| (FAT32(pmp) && dirclust == pmp->pm_rootdirblk))
119			&& diroffset == MSDOSFSROOT_OFS) {
120			/*
121			* Directory entry for the root directory. There isn't one,
122			* so we manufacture one. We should probably rummage
123			* through the root directory and find a label entry (if it
124			* exists), and then use the time and date from that entry
125			* as the time and date for the root denode.
126			*/
127			ldep->de_mkfsvnode = (struct mkfsvnode *)-1;
128
129			ldep->de_Attributes = ATTR_DIRECTORY;
130			if (FAT32(pmp))
131			ldep->de_StartCluster = pmp->pm_rootdirblk;
132			/* de_FileSize will be filled in further down */
133			else {
134			ldep->de_StartCluster = MSDOSFSROOT;
135			ldep->de_FileSize = pmp->pm_rootdirsize * pmp->pm_BytesPerSec;
136			}
137			/*
138			* fill in time and date so that dos2unixtime() doesn't
139			* spit up when called from msdosfs_getattr() with root
140			* denode
141			*/
142			ldep->de_CHun = 0;
143			ldep->de_CTime = 0x0000; /* 00:00:00 */
144			ldep->de_CDate = (0 << DD_YEAR_SHIFT) \| (1 << DD_MONTH_SHIFT)
145			\| (1 << DD_DAY_SHIFT);
146			/* Jan 1, 1980 */
147			ldep->de_ADate = ldep->de_CDate;
148			ldep->de_MTime = ldep->de_CTime;
149			ldep->de_MDate = ldep->de_CDate;
150			/* leave the other fields as garbage */
151			} else {
152			error = readep(pmp, dirclust, diroffset, &bp, &direntptr);
153			if (error) {
154			ldep->de_devvp = NULL;
155			ldep->de_Name[0] = SLOT_DELETED;
156			return (error);
157			}
158			DE_INTERNALIZE(ldep, direntptr);
159			brelse(bp, 0);
160			}
161
162			/*
163			* Fill in a few fields of the mkfsvnode and finish filling in the
164			* denode. Then return the address of the found denode.
165			*/
166			if (ldep->de_Attributes & ATTR_DIRECTORY) {
167			/*
168			* Since DOS directory entries that describe directories
169			* have 0 in the filesize field, we take this opportunity
170			* to find out the length of the directory and plug it into
171			* the denode structure.
172			*/
173			u_long size;
174
175			if (ldep->de_StartCluster != MSDOSFSROOT) {
176			error = pcbmap(ldep, CLUST_END, 0, &size, 0);
177			if (error == E2BIG) {
178			ldep->de_FileSize = de_cn2off(pmp, size);
179			error = 0;
180			} else
181			printf("deget(): pcbmap returned %d\n", error);
182			}
183			}
184			*depp = ldep;
185			return (0);
186			}
187
188			/*
189			* Truncate the file described by dep to the length specified by length.
190			*/
191			int
192			detrunc(struct denode *dep, u_long length, int flags)
193			{
194			int error;
195			int allerror = 0;
196			u_long eofentry;
197			u_long chaintofree = 0;
198			daddr_t bn, lastblock;
199			int boff;
200			int isadir = dep->de_Attributes & ATTR_DIRECTORY;
201			struct mkfsbuf *bp;
202			struct msdosfsmount *pmp = dep->de_pmp;
203
204			#ifdef MSDOSFS_DEBUG
205			printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags);
206			#endif
207
208			/*
209			* Disallow attempts to truncate the root directory since it is of
210			* fixed size. That's just the way dos filesystems are. We use
211			* the VROOT bit in the mkfsvnode because checking for the directory
212			* bit and a startcluster of 0 in the denode is not adequate to
213			* recognize the root directory at this point in a file or
214			* directory's life.
215			*/
216			if (dep->de_mkfsvnode != NULL && !FAT32(pmp)) {
217			printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n",
218			dep->de_dirclust, dep->de_diroffset);
219			return (EINVAL);
220			}
221
222			if (dep->de_FileSize < length)
223			return (deextend(dep, length));
224			lastblock = de_clcount(pmp, length) - 1;
225
226			/*
227			* If the desired length is 0 then remember the starting cluster of
228			* the file and set the StartCluster field in the directory entry
229			* to 0. If the desired length is not zero, then get the number of
230			* the last cluster in the shortened file. Then get the number of
231			* the first cluster in the part of the file that is to be freed.
232			* Then set the next cluster pointer in the last cluster of the
233			* file to CLUST_EOFE.
234			*/
235			if (length == 0) {
236			chaintofree = dep->de_StartCluster;
237			dep->de_StartCluster = 0;
238			eofentry = ~0;
239			} else {
240			error = pcbmap(dep, lastblock, 0, &eofentry, 0);
241			if (error) {
242			#ifdef MSDOSFS_DEBUG
243			printf("detrunc(): pcbmap fails %d\n", error);
244			#endif
245			return (error);
246			}
247			}
248
249			/*
250			* If the new length is not a multiple of the cluster size then we
251			* must zero the tail end of the new last cluster in case it
252			* becomes part of the file again because of a seek.
253			*/
254			if ((boff = length & pmp->pm_crbomask) != 0) {
255			if (isadir) {
256			bn = cntobn(pmp, eofentry);
257			error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn),
258			pmp->pm_bpcluster, B_MODIFY, &bp);
259			if (error) {
260			#ifdef MSDOSFS_DEBUG
261			printf("detrunc(): bread fails %d\n", error);
262			#endif
263			return (error);
264			}
265			memset((char *)bp->b_data + boff, 0,
266			pmp->pm_bpcluster - boff);
267			if (flags & IO_SYNC)
268			bwrite(bp);
269			else
270			bdwrite(bp);
271			}
272			}
273
274			/*
275			* Write out the updated directory entry. Even if the update fails
276			* we free the trailing clusters.
277			*/
278			dep->de_FileSize = length;
279			if (!isadir)
280			dep->de_flag \|= DE_UPDATE\|DE_MODIFIED;
281			#ifdef MSDOSFS_DEBUG
282			printf("detrunc(): allerror %d, eofentry %lu\n",
283			allerror, eofentry);
284			#endif
285
286			/*
287			* If we need to break the cluster chain for the file then do it
288			* now.
289			*/
290			if (eofentry != (u_long)~0) {
291			error = fatentry(FAT_GET_AND_SET, pmp, eofentry,
292			&chaintofree, CLUST_EOFE);
293			if (error) {
294			#ifdef MSDOSFS_DEBUG
295			printf("detrunc(): fatentry errors %d\n", error);
296			#endif
297			return (error);
298			}
299			}
300
301			/*
302			* Now free the clusters removed from the file because of the
303			* truncation.
304			*/
305			if (chaintofree != 0 && !MSDOSFSEOF(chaintofree, pmp->pm_fatmask))
306			freeclusterchain(pmp, chaintofree);
307
308			return (allerror);
309			}
310
311			/*
312			* Extend the file described by dep to length specified by length.
313			*/
314			int
315			deextend(struct denode *dep, u_long length)
316			{
317			struct msdosfsmount *pmp = dep->de_pmp;
318			u_long count;
319			int error;
320
321			/*
322			* The root of a DOS filesystem cannot be extended.
323			*/
324			if (dep->de_mkfsvnode != NULL && !FAT32(pmp))
325			return EINVAL;
326
327			/*
328			* Directories cannot be extended.
329			*/
330			if (dep->de_Attributes & ATTR_DIRECTORY)
331			return EISDIR;
332
333			if (length <= dep->de_FileSize)
334			return E2BIG;
335
336			/*
337			* Compute the number of clusters to allocate.
338			*/
339			count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize);
340			if (count > 0) {
341			if (count > pmp->pm_freeclustercount)
342			return (ENOSPC);
343			error = extendfile(dep, count, NULL, NULL, DE_CLEAR);
344			if (error) {
345			/* truncate the added clusters away again */
346			(void) detrunc(dep, dep->de_FileSize, 0);
347			return (error);
348			}
349			}
350
351			/*
352			* Zero extend file range; ubc_zerorange() uses ubc_alloc() and a
353			* memset(); we set the write size so ubc won't read in file data that
354			* is zero'd later.
355			*/
356			dep->de_FileSize = length;
357			dep->de_flag \|= DE_UPDATE\|DE_MODIFIED;
358			return 0;
359			}