xref: /freebsd/sys/fs/msdosfs/msdosfs_vnops.c (revision 8fa113e5fc65fe6abc757f0089f477a87ee4d185)
1 /* $FreeBSD$ */
2 /*	$NetBSD: msdosfs_vnops.c,v 1.68 1998/02/10 14:10:04 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/namei.h>
54 #include <sys/resourcevar.h>	/* defines plimit structure in proc struct */
55 #include <sys/kernel.h>
56 #include <sys/stat.h>
57 #include <sys/bio.h>
58 #include <sys/buf.h>
59 #include <sys/proc.h>
60 #include <sys/mount.h>
61 #include <sys/unistd.h>
62 #include <sys/vnode.h>
63 #include <sys/malloc.h>
64 #include <sys/dirent.h>
65 #include <sys/signalvar.h>
66 
67 #include <vm/vm.h>
68 #include <vm/vm_extern.h>
69 #include <vm/vnode_pager.h>
70 
71 #include <machine/mutex.h>
72 
73 #include <fs/msdosfs/bpb.h>
74 #include <fs/msdosfs/direntry.h>
75 #include <fs/msdosfs/denode.h>
76 #include <fs/msdosfs/msdosfsmount.h>
77 #include <fs/msdosfs/fat.h>
78 
79 #define	DOS_FILESIZE_MAX	0xffffffff
80 
81 /*
82  * Prototypes for MSDOSFS vnode operations
83  */
84 static int msdosfs_create __P((struct vop_create_args *));
85 static int msdosfs_mknod __P((struct vop_mknod_args *));
86 static int msdosfs_close __P((struct vop_close_args *));
87 static int msdosfs_access __P((struct vop_access_args *));
88 static int msdosfs_getattr __P((struct vop_getattr_args *));
89 static int msdosfs_setattr __P((struct vop_setattr_args *));
90 static int msdosfs_read __P((struct vop_read_args *));
91 static int msdosfs_write __P((struct vop_write_args *));
92 static int msdosfs_fsync __P((struct vop_fsync_args *));
93 static int msdosfs_remove __P((struct vop_remove_args *));
94 static int msdosfs_link __P((struct vop_link_args *));
95 static int msdosfs_rename __P((struct vop_rename_args *));
96 static int msdosfs_mkdir __P((struct vop_mkdir_args *));
97 static int msdosfs_rmdir __P((struct vop_rmdir_args *));
98 static int msdosfs_symlink __P((struct vop_symlink_args *));
99 static int msdosfs_readdir __P((struct vop_readdir_args *));
100 static int msdosfs_bmap __P((struct vop_bmap_args *));
101 static int msdosfs_strategy __P((struct vop_strategy_args *));
102 static int msdosfs_print __P((struct vop_print_args *));
103 static int msdosfs_pathconf __P((struct vop_pathconf_args *ap));
104 
105 /*
106  * Some general notes:
107  *
108  * In the ufs filesystem the inodes, superblocks, and indirect blocks are
109  * read/written using the vnode for the filesystem. Blocks that represent
110  * the contents of a file are read/written using the vnode for the file
111  * (including directories when they are read/written as files). This
112  * presents problems for the dos filesystem because data that should be in
113  * an inode (if dos had them) resides in the directory itself.  Since we
114  * must update directory entries without the benefit of having the vnode
115  * for the directory we must use the vnode for the filesystem.  This means
116  * that when a directory is actually read/written (via read, write, or
117  * readdir, or seek) we must use the vnode for the filesystem instead of
118  * the vnode for the directory as would happen in ufs. This is to insure we
119  * retreive the correct block from the buffer cache since the hash value is
120  * based upon the vnode address and the desired block number.
121  */
122 
123 /*
124  * Create a regular file. On entry the directory to contain the file being
125  * created is locked.  We must release before we return. We must also free
126  * the pathname buffer pointed at by cnp->cn_pnbuf, always on error, or
127  * only if the SAVESTART bit in cn_flags is clear on success.
128  */
129 static int
130 msdosfs_create(ap)
131 	struct vop_create_args /* {
132 		struct vnode *a_dvp;
133 		struct vnode **a_vpp;
134 		struct componentname *a_cnp;
135 		struct vattr *a_vap;
136 	} */ *ap;
137 {
138 	struct componentname *cnp = ap->a_cnp;
139 	struct denode ndirent;
140 	struct denode *dep;
141 	struct denode *pdep = VTODE(ap->a_dvp);
142 	struct timespec ts;
143 	int error;
144 
145 #ifdef MSDOSFS_DEBUG
146 	printf("msdosfs_create(cnp %p, vap %p\n", cnp, ap->a_vap);
147 #endif
148 
149 	/*
150 	 * If this is the root directory and there is no space left we
151 	 * can't do anything.  This is because the root directory can not
152 	 * change size.
153 	 */
154 	if (pdep->de_StartCluster == MSDOSFSROOT
155 	    && pdep->de_fndoffset >= pdep->de_FileSize) {
156 		error = ENOSPC;
157 		goto bad;
158 	}
159 
160 	/*
161 	 * Create a directory entry for the file, then call createde() to
162 	 * have it installed. NOTE: DOS files are always executable.  We
163 	 * use the absence of the owner write bit to make the file
164 	 * readonly.
165 	 */
166 #ifdef DIAGNOSTIC
167 	if ((cnp->cn_flags & HASBUF) == 0)
168 		panic("msdosfs_create: no name");
169 #endif
170 	bzero(&ndirent, sizeof(ndirent));
171 	error = uniqdosname(pdep, cnp, ndirent.de_Name);
172 	if (error)
173 		goto bad;
174 
175 	ndirent.de_Attributes = (ap->a_vap->va_mode & VWRITE) ?
176 				ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY;
177 	ndirent.de_LowerCase = 0;
178 	ndirent.de_StartCluster = 0;
179 	ndirent.de_FileSize = 0;
180 	ndirent.de_dev = pdep->de_dev;
181 	ndirent.de_devvp = pdep->de_devvp;
182 	ndirent.de_pmp = pdep->de_pmp;
183 	ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
184 	getnanotime(&ts);
185 	DETIMES(&ndirent, &ts, &ts, &ts);
186 	error = createde(&ndirent, pdep, &dep, cnp);
187 	if (error)
188 		goto bad;
189 	*ap->a_vpp = DETOV(dep);
190 	return (0);
191 
192 bad:
193 	return (error);
194 }
195 
196 static int
197 msdosfs_mknod(ap)
198 	struct vop_mknod_args /* {
199 		struct vnode *a_dvp;
200 		struct vnode **a_vpp;
201 		struct componentname *a_cnp;
202 		struct vattr *a_vap;
203 	} */ *ap;
204 {
205     return (EINVAL);
206 }
207 
208 static int
209 msdosfs_close(ap)
210 	struct vop_close_args /* {
211 		struct vnode *a_vp;
212 		int a_fflag;
213 		struct ucred *a_cred;
214 		struct thread *a_td;
215 	} */ *ap;
216 {
217 	struct vnode *vp = ap->a_vp;
218 	struct denode *dep = VTODE(vp);
219 	struct timespec ts;
220 
221 	mtx_lock(&vp->v_interlock);
222 	if (vp->v_usecount > 1) {
223 		getnanotime(&ts);
224 		DETIMES(dep, &ts, &ts, &ts);
225 	}
226 	mtx_unlock(&vp->v_interlock);
227 	return 0;
228 }
229 
230 static int
231 msdosfs_access(ap)
232 	struct vop_access_args /* {
233 		struct vnode *a_vp;
234 		int a_mode;
235 		struct ucred *a_cred;
236 		struct thread *a_td;
237 	} */ *ap;
238 {
239 	struct vnode *vp = ap->a_vp;
240 	struct denode *dep = VTODE(ap->a_vp);
241 	struct msdosfsmount *pmp = dep->de_pmp;
242 	mode_t file_mode, mode = ap->a_mode;
243 
244 	file_mode = (S_IXUSR|S_IXGRP|S_IXOTH) | (S_IRUSR|S_IRGRP|S_IROTH) |
245 	    ((dep->de_Attributes & ATTR_READONLY) ? 0 : (S_IWUSR|S_IWGRP|S_IWOTH));
246 	file_mode &= pmp->pm_mask;
247 
248 	/*
249 	 * Disallow write attempts on read-only file systems;
250 	 * unless the file is a socket, fifo, or a block or
251 	 * character device resident on the file system.
252 	 */
253 	if (mode & VWRITE) {
254 		switch (vp->v_type) {
255 		case VDIR:
256 		case VLNK:
257 		case VREG:
258 			if (vp->v_mount->mnt_flag & MNT_RDONLY)
259 				return (EROFS);
260 			break;
261 		default:
262 			break;
263 		}
264 	}
265 
266 	return (vaccess(vp->v_type, file_mode, pmp->pm_uid, pmp->pm_gid,
267 	    ap->a_mode, ap->a_cred, NULL));
268 }
269 
270 static int
271 msdosfs_getattr(ap)
272 	struct vop_getattr_args /* {
273 		struct vnode *a_vp;
274 		struct vattr *a_vap;
275 		struct ucred *a_cred;
276 		struct thread *a_td;
277 	} */ *ap;
278 {
279 	struct denode *dep = VTODE(ap->a_vp);
280 	struct msdosfsmount *pmp = dep->de_pmp;
281 	struct vattr *vap = ap->a_vap;
282 	mode_t mode;
283 	struct timespec ts;
284 	u_long dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
285 	u_long fileid;
286 
287 	getnanotime(&ts);
288 	DETIMES(dep, &ts, &ts, &ts);
289 	vap->va_fsid = dev2udev(dep->de_dev);
290 	/*
291 	 * The following computation of the fileid must be the same as that
292 	 * used in msdosfs_readdir() to compute d_fileno. If not, pwd
293 	 * doesn't work.
294 	 */
295 	if (dep->de_Attributes & ATTR_DIRECTORY) {
296 		fileid = cntobn(pmp, dep->de_StartCluster) * dirsperblk;
297 		if (dep->de_StartCluster == MSDOSFSROOT)
298 			fileid = 1;
299 	} else {
300 		fileid = cntobn(pmp, dep->de_dirclust) * dirsperblk;
301 		if (dep->de_dirclust == MSDOSFSROOT)
302 			fileid = roottobn(pmp, 0) * dirsperblk;
303 		fileid += dep->de_diroffset / sizeof(struct direntry);
304 	}
305 	vap->va_fileid = fileid;
306 	if ((dep->de_Attributes & ATTR_READONLY) == 0)
307 		mode = S_IRWXU|S_IRWXG|S_IRWXO;
308 	else
309 		mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
310 	vap->va_mode = mode & pmp->pm_mask;
311 	vap->va_uid = pmp->pm_uid;
312 	vap->va_gid = pmp->pm_gid;
313 	vap->va_nlink = 1;
314 	vap->va_rdev = 0;
315 	vap->va_size = dep->de_FileSize;
316 	dos2unixtime(dep->de_MDate, dep->de_MTime, 0, &vap->va_mtime);
317 	if (pmp->pm_flags & MSDOSFSMNT_LONGNAME) {
318 		dos2unixtime(dep->de_ADate, 0, 0, &vap->va_atime);
319 		dos2unixtime(dep->de_CDate, dep->de_CTime, dep->de_CHun, &vap->va_ctime);
320 	} else {
321 		vap->va_atime = vap->va_mtime;
322 		vap->va_ctime = vap->va_mtime;
323 	}
324 	vap->va_flags = 0;
325 	if ((dep->de_Attributes & ATTR_ARCHIVE) == 0)
326 		vap->va_flags |= SF_ARCHIVED;
327 	vap->va_gen = 0;
328 	vap->va_blocksize = pmp->pm_bpcluster;
329 	vap->va_bytes =
330 	    (dep->de_FileSize + pmp->pm_crbomask) & ~pmp->pm_crbomask;
331 	vap->va_type = ap->a_vp->v_type;
332 	vap->va_filerev = dep->de_modrev;
333 	return (0);
334 }
335 
336 static int
337 msdosfs_setattr(ap)
338 	struct vop_setattr_args /* {
339 		struct vnode *a_vp;
340 		struct vattr *a_vap;
341 		struct ucred *a_cred;
342 		struct thread *a_td;
343 	} */ *ap;
344 {
345 	struct vnode *vp = ap->a_vp;
346 	struct denode *dep = VTODE(ap->a_vp);
347 	struct msdosfsmount *pmp = dep->de_pmp;
348 	struct vattr *vap = ap->a_vap;
349 	struct ucred *cred = ap->a_cred;
350 	int error = 0;
351 
352 #ifdef MSDOSFS_DEBUG
353 	printf("msdosfs_setattr(): vp %p, vap %p, cred %p, p %p\n",
354 	    ap->a_vp, vap, cred, ap->a_td);
355 #endif
356 
357 	/*
358 	 * Check for unsettable attributes.
359 	 */
360 	if ((vap->va_type != VNON) || (vap->va_nlink != VNOVAL) ||
361 	    (vap->va_fsid != VNOVAL) || (vap->va_fileid != VNOVAL) ||
362 	    (vap->va_blocksize != VNOVAL) || (vap->va_rdev != VNOVAL) ||
363 	    (vap->va_bytes != VNOVAL) || (vap->va_gen != VNOVAL)) {
364 #ifdef MSDOSFS_DEBUG
365 		printf("msdosfs_setattr(): returning EINVAL\n");
366 		printf("    va_type %d, va_nlink %x, va_fsid %lx, va_fileid %lx\n",
367 		    vap->va_type, vap->va_nlink, vap->va_fsid, vap->va_fileid);
368 		printf("    va_blocksize %lx, va_rdev %x, va_bytes %qx, va_gen %lx\n",
369 		    vap->va_blocksize, vap->va_rdev, vap->va_bytes, vap->va_gen);
370 		printf("    va_uid %x, va_gid %x\n",
371 		    vap->va_uid, vap->va_gid);
372 #endif
373 		return (EINVAL);
374 	}
375 	if (vap->va_flags != VNOVAL) {
376 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
377 			return (EROFS);
378 		if (cred->cr_uid != pmp->pm_uid &&
379 		    (error = suser_xxx(cred, ap->a_td->td_proc, PRISON_ROOT)))
380 			return (error);
381 		/*
382 		 * We are very inconsistent about handling unsupported
383 		 * attributes.  We ignored the access time and the
384 		 * read and execute bits.  We were strict for the other
385 		 * attributes.
386 		 *
387 		 * Here we are strict, stricter than ufs in not allowing
388 		 * users to attempt to set SF_SETTABLE bits or anyone to
389 		 * set unsupported bits.  However, we ignore attempts to
390 		 * set ATTR_ARCHIVE for directories `cp -pr' from a more
391 		 * sensible file system attempts it a lot.
392 		 */
393 		if (suser_xxx(cred, ap->a_td->td_proc, PRISON_ROOT)) {
394 			if (vap->va_flags & SF_SETTABLE)
395 				return EPERM;
396 		}
397 		if (vap->va_flags & ~SF_ARCHIVED)
398 			return EOPNOTSUPP;
399 		if (vap->va_flags & SF_ARCHIVED)
400 			dep->de_Attributes &= ~ATTR_ARCHIVE;
401 		else if (!(dep->de_Attributes & ATTR_DIRECTORY))
402 			dep->de_Attributes |= ATTR_ARCHIVE;
403 		dep->de_flag |= DE_MODIFIED;
404 	}
405 
406 	if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
407 		uid_t uid;
408 		gid_t gid;
409 
410 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
411 			return (EROFS);
412 		uid = vap->va_uid;
413 		if (uid == (uid_t)VNOVAL)
414 			uid = pmp->pm_uid;
415 		gid = vap->va_gid;
416 		if (gid == (gid_t)VNOVAL)
417 			gid = pmp->pm_gid;
418 		if ((cred->cr_uid != pmp->pm_uid || uid != pmp->pm_uid ||
419 		    (gid != pmp->pm_gid && !groupmember(gid, cred))) &&
420 		    (error = suser_xxx(cred, ap->a_td->td_proc, PRISON_ROOT)))
421 			return error;
422 		if (uid != pmp->pm_uid || gid != pmp->pm_gid)
423 			return EINVAL;
424 	}
425 
426 	if (vap->va_size != VNOVAL) {
427 		/*
428 		 * Disallow write attempts on read-only file systems;
429 		 * unless the file is a socket, fifo, or a block or
430 		 * character device resident on the file system.
431 		 */
432 		switch (vp->v_type) {
433 		case VDIR:
434 			return (EISDIR);
435 			/* NOT REACHED */
436 		case VLNK:
437 		case VREG:
438 			if (vp->v_mount->mnt_flag & MNT_RDONLY)
439 				return (EROFS);
440 			break;
441 		default:
442 			break;
443 		}
444 		error = detrunc(dep, vap->va_size, 0, cred, ap->a_td);
445 		if (error)
446 			return error;
447 	}
448 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
449 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
450 			return (EROFS);
451 		if (cred->cr_uid != pmp->pm_uid &&
452 		    (error = suser_xxx(cred, ap->a_td->td_proc, PRISON_ROOT)) &&
453 		    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
454 		    (error = VOP_ACCESS(ap->a_vp, VWRITE, cred, ap->a_td))))
455 			return (error);
456 		if (vp->v_type != VDIR) {
457 			if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) == 0 &&
458 			    vap->va_atime.tv_sec != VNOVAL)
459 				unix2dostime(&vap->va_atime, &dep->de_ADate, NULL, NULL);
460 			if (vap->va_mtime.tv_sec != VNOVAL)
461 				unix2dostime(&vap->va_mtime, &dep->de_MDate, &dep->de_MTime, NULL);
462 			dep->de_Attributes |= ATTR_ARCHIVE;
463 			dep->de_flag |= DE_MODIFIED;
464 		}
465 	}
466 	/*
467 	 * DOS files only have the ability to have their writability
468 	 * attribute set, so we use the owner write bit to set the readonly
469 	 * attribute.
470 	 */
471 	if (vap->va_mode != (mode_t)VNOVAL) {
472 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
473 			return (EROFS);
474 		if (cred->cr_uid != pmp->pm_uid &&
475 		    (error = suser_xxx(cred, ap->a_td->td_proc, PRISON_ROOT)))
476 			return (error);
477 		if (vp->v_type != VDIR) {
478 			/* We ignore the read and execute bits. */
479 			if (vap->va_mode & VWRITE)
480 				dep->de_Attributes &= ~ATTR_READONLY;
481 			else
482 				dep->de_Attributes |= ATTR_READONLY;
483 			dep->de_flag |= DE_MODIFIED;
484 		}
485 	}
486 	return (deupdat(dep, 1));
487 }
488 
489 static int
490 msdosfs_read(ap)
491 	struct vop_read_args /* {
492 		struct vnode *a_vp;
493 		struct uio *a_uio;
494 		int a_ioflag;
495 		struct ucred *a_cred;
496 	} */ *ap;
497 {
498 	int error = 0;
499 	int blsize;
500 	int isadir;
501 	int orig_resid;
502 	u_int n;
503 	u_long diff;
504 	u_long on;
505 	daddr_t lbn;
506 	daddr_t rablock;
507 	int rasize;
508 	int seqcount;
509 	struct buf *bp;
510 	struct vnode *vp = ap->a_vp;
511 	struct denode *dep = VTODE(vp);
512 	struct msdosfsmount *pmp = dep->de_pmp;
513 	struct uio *uio = ap->a_uio;
514 
515 	if (uio->uio_offset < 0)
516 		return (EINVAL);
517 
518 	if ((uoff_t)uio->uio_offset > DOS_FILESIZE_MAX)
519                 return (0);
520 	/*
521 	 * If they didn't ask for any data, then we are done.
522 	 */
523 	orig_resid = uio->uio_resid;
524 	if (orig_resid <= 0)
525 		return (0);
526 
527 	seqcount = ap->a_ioflag >> 16;
528 
529 	isadir = dep->de_Attributes & ATTR_DIRECTORY;
530 	do {
531 		if (uio->uio_offset >= dep->de_FileSize)
532 			break;
533 		lbn = de_cluster(pmp, uio->uio_offset);
534 		/*
535 		 * If we are operating on a directory file then be sure to
536 		 * do i/o with the vnode for the filesystem instead of the
537 		 * vnode for the directory.
538 		 */
539 		if (isadir) {
540 			/* convert cluster # to block # */
541 			error = pcbmap(dep, lbn, &lbn, 0, &blsize);
542 			if (error == E2BIG) {
543 				error = EINVAL;
544 				break;
545 			} else if (error)
546 				break;
547 			error = bread(pmp->pm_devvp, lbn, blsize, NOCRED, &bp);
548 		} else {
549 			blsize = pmp->pm_bpcluster;
550 			rablock = lbn + 1;
551 			if (seqcount > 1 &&
552 			    de_cn2off(pmp, rablock) < dep->de_FileSize) {
553 				rasize = pmp->pm_bpcluster;
554 				error = breadn(vp, lbn, blsize,
555 				    &rablock, &rasize, 1, NOCRED, &bp);
556 			} else {
557 				error = bread(vp, lbn, blsize, NOCRED, &bp);
558 			}
559 		}
560 		if (error) {
561 			brelse(bp);
562 			break;
563 		}
564 		on = uio->uio_offset & pmp->pm_crbomask;
565 		diff = pmp->pm_bpcluster - on;
566 		n = diff > uio->uio_resid ? uio->uio_resid : diff;
567 		diff = dep->de_FileSize - uio->uio_offset;
568 		if (diff < n)
569 			n = diff;
570 		diff = blsize - bp->b_resid;
571 		if (diff < n)
572 			n = diff;
573 		error = uiomove(bp->b_data + on, (int) n, uio);
574 		brelse(bp);
575 	} while (error == 0 && uio->uio_resid > 0 && n != 0);
576 	if (!isadir && (error == 0 || uio->uio_resid != orig_resid) &&
577 	    (vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
578 		dep->de_flag |= DE_ACCESS;
579 	return (error);
580 }
581 
582 /*
583  * Write data to a file or directory.
584  */
585 static int
586 msdosfs_write(ap)
587 	struct vop_write_args /* {
588 		struct vnode *a_vp;
589 		struct uio *a_uio;
590 		int a_ioflag;
591 		struct ucred *a_cred;
592 	} */ *ap;
593 {
594 	int n;
595 	int croffset;
596 	int resid;
597 	u_long osize;
598 	int error = 0;
599 	u_long count;
600 	daddr_t bn, lastcn;
601 	struct buf *bp;
602 	int ioflag = ap->a_ioflag;
603 	struct uio *uio = ap->a_uio;
604 	struct thread *td = uio->uio_td;
605 	struct vnode *vp = ap->a_vp;
606 	struct vnode *thisvp;
607 	struct denode *dep = VTODE(vp);
608 	struct msdosfsmount *pmp = dep->de_pmp;
609 	struct ucred *cred = ap->a_cred;
610 
611 #ifdef MSDOSFS_DEBUG
612 	printf("msdosfs_write(vp %p, uio %p, ioflag %x, cred %p\n",
613 	    vp, uio, ioflag, cred);
614 	printf("msdosfs_write(): diroff %lu, dirclust %lu, startcluster %lu\n",
615 	    dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster);
616 #endif
617 
618 	switch (vp->v_type) {
619 	case VREG:
620 		if (ioflag & IO_APPEND)
621 			uio->uio_offset = dep->de_FileSize;
622 		thisvp = vp;
623 		break;
624 	case VDIR:
625 		return EISDIR;
626 	default:
627 		panic("msdosfs_write(): bad file type");
628 	}
629 
630 	if (uio->uio_offset < 0)
631 		return (EFBIG);
632 
633 	if (uio->uio_resid == 0)
634 		return (0);
635 
636 	/*
637 	 * If they've exceeded their filesize limit, tell them about it.
638 	 */
639 	if (td &&
640 	    ((uoff_t)uio->uio_offset + uio->uio_resid >
641 	    td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur)) {
642 		PROC_LOCK(td->td_proc);
643 		psignal(td->td_proc, SIGXFSZ);
644 		PROC_UNLOCK(td->td_proc);
645 		return (EFBIG);
646 	}
647 
648 	if ((uoff_t)uio->uio_offset + uio->uio_resid > DOS_FILESIZE_MAX)
649                 return (EFBIG);
650 
651 	/*
652 	 * If the offset we are starting the write at is beyond the end of
653 	 * the file, then they've done a seek.  Unix filesystems allow
654 	 * files with holes in them, DOS doesn't so we must fill the hole
655 	 * with zeroed blocks.
656 	 */
657 	if (uio->uio_offset > dep->de_FileSize) {
658 		error = deextend(dep, uio->uio_offset, cred);
659 		if (error)
660 			return (error);
661 	}
662 
663 	/*
664 	 * Remember some values in case the write fails.
665 	 */
666 	resid = uio->uio_resid;
667 	osize = dep->de_FileSize;
668 
669 	/*
670 	 * If we write beyond the end of the file, extend it to its ultimate
671 	 * size ahead of the time to hopefully get a contiguous area.
672 	 */
673 	if (uio->uio_offset + resid > osize) {
674 		count = de_clcount(pmp, uio->uio_offset + resid) -
675 			de_clcount(pmp, osize);
676 		error = extendfile(dep, count, NULL, NULL, 0);
677 		if (error &&  (error != ENOSPC || (ioflag & IO_UNIT)))
678 			goto errexit;
679 		lastcn = dep->de_fc[FC_LASTFC].fc_frcn;
680 	} else
681 		lastcn = de_clcount(pmp, osize) - 1;
682 
683 	do {
684 		if (de_cluster(pmp, uio->uio_offset) > lastcn) {
685 			error = ENOSPC;
686 			break;
687 		}
688 
689 		croffset = uio->uio_offset & pmp->pm_crbomask;
690 		n = min(uio->uio_resid, pmp->pm_bpcluster - croffset);
691 		if (uio->uio_offset + n > dep->de_FileSize) {
692 			dep->de_FileSize = uio->uio_offset + n;
693 			/* The object size needs to be set before buffer is allocated */
694 			vnode_pager_setsize(vp, dep->de_FileSize);
695 		}
696 
697 		bn = de_cluster(pmp, uio->uio_offset);
698 		if ((uio->uio_offset & pmp->pm_crbomask) == 0
699 		    && (de_cluster(pmp, uio->uio_offset + uio->uio_resid)
700 		        > de_cluster(pmp, uio->uio_offset)
701 			|| uio->uio_offset + uio->uio_resid >= dep->de_FileSize)) {
702 			/*
703 			 * If either the whole cluster gets written,
704 			 * or we write the cluster from its start beyond EOF,
705 			 * then no need to read data from disk.
706 			 */
707 			bp = getblk(thisvp, bn, pmp->pm_bpcluster, 0, 0);
708 			clrbuf(bp);
709 			/*
710 			 * Do the bmap now, since pcbmap needs buffers
711 			 * for the fat table. (see msdosfs_strategy)
712 			 */
713 			if (bp->b_blkno == bp->b_lblkno) {
714 				error = pcbmap(dep, bp->b_lblkno, &bp->b_blkno,
715 				     0, 0);
716 				if (error)
717 					bp->b_blkno = -1;
718 			}
719 			if (bp->b_blkno == -1) {
720 				brelse(bp);
721 				if (!error)
722 					error = EIO;		/* XXX */
723 				break;
724 			}
725 		} else {
726 			/*
727 			 * The block we need to write into exists, so read it in.
728 			 */
729 			error = bread(thisvp, bn, pmp->pm_bpcluster, cred, &bp);
730 			if (error) {
731 				brelse(bp);
732 				break;
733 			}
734 		}
735 
736 		/*
737 		 * Should these vnode_pager_* functions be done on dir
738 		 * files?
739 		 */
740 
741 		/*
742 		 * Copy the data from user space into the buf header.
743 		 */
744 		error = uiomove(bp->b_data + croffset, n, uio);
745 		if (error) {
746 			brelse(bp);
747 			break;
748 		}
749 
750 		/*
751 		 * If they want this synchronous then write it and wait for
752 		 * it.  Otherwise, if on a cluster boundary write it
753 		 * asynchronously so we can move on to the next block
754 		 * without delay.  Otherwise do a delayed write because we
755 		 * may want to write somemore into the block later.
756 		 */
757 		if (ioflag & IO_SYNC)
758 			(void) bwrite(bp);
759 		else if (n + croffset == pmp->pm_bpcluster)
760 			bawrite(bp);
761 		else
762 			bdwrite(bp);
763 		dep->de_flag |= DE_UPDATE;
764 	} while (error == 0 && uio->uio_resid > 0);
765 
766 	/*
767 	 * If the write failed and they want us to, truncate the file back
768 	 * to the size it was before the write was attempted.
769 	 */
770 errexit:
771 	if (error) {
772 		if (ioflag & IO_UNIT) {
773 			detrunc(dep, osize, ioflag & IO_SYNC, NOCRED, NULL);
774 			uio->uio_offset -= resid - uio->uio_resid;
775 			uio->uio_resid = resid;
776 		} else {
777 			detrunc(dep, dep->de_FileSize, ioflag & IO_SYNC, NOCRED, NULL);
778 			if (uio->uio_resid != resid)
779 				error = 0;
780 		}
781 	} else if (ioflag & IO_SYNC)
782 		error = deupdat(dep, 1);
783 	return (error);
784 }
785 
786 /*
787  * Flush the blocks of a file to disk.
788  *
789  * This function is worthless for vnodes that represent directories. Maybe we
790  * could just do a sync if they try an fsync on a directory file.
791  */
792 static int
793 msdosfs_fsync(ap)
794 	struct vop_fsync_args /* {
795 		struct vnode *a_vp;
796 		struct ucred *a_cred;
797 		int a_waitfor;
798 		struct thread *a_td;
799 	} */ *ap;
800 {
801 	struct vnode *vp = ap->a_vp;
802 	int s;
803 	struct buf *bp, *nbp;
804 
805 	/*
806 	 * Flush all dirty buffers associated with a vnode.
807 	 */
808 loop:
809 	s = splbio();
810 	for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
811 		nbp = TAILQ_NEXT(bp, b_vnbufs);
812 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT))
813 			continue;
814 		if ((bp->b_flags & B_DELWRI) == 0)
815 			panic("msdosfs_fsync: not dirty");
816 		bremfree(bp);
817 		splx(s);
818 		(void) bwrite(bp);
819 		goto loop;
820 	}
821 	while (vp->v_numoutput) {
822 		vp->v_flag |= VBWAIT;
823 		(void) tsleep((caddr_t)&vp->v_numoutput, PRIBIO + 1, "msdosfsn", 0);
824 	}
825 #ifdef DIAGNOSTIC
826 	if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
827 		vprint("msdosfs_fsync: dirty", vp);
828 		goto loop;
829 	}
830 #endif
831 	splx(s);
832 	return (deupdat(VTODE(vp), ap->a_waitfor == MNT_WAIT));
833 }
834 
835 static int
836 msdosfs_remove(ap)
837 	struct vop_remove_args /* {
838 		struct vnode *a_dvp;
839 		struct vnode *a_vp;
840 		struct componentname *a_cnp;
841 	} */ *ap;
842 {
843 	struct denode *dep = VTODE(ap->a_vp);
844 	struct denode *ddep = VTODE(ap->a_dvp);
845 	int error;
846 
847 	if (ap->a_vp->v_type == VDIR)
848 		error = EPERM;
849 	else
850 		error = removede(ddep, dep);
851 #ifdef MSDOSFS_DEBUG
852 	printf("msdosfs_remove(), dep %p, v_usecount %d\n", dep, ap->a_vp->v_usecount);
853 #endif
854 	return (error);
855 }
856 
857 /*
858  * DOS filesystems don't know what links are.
859  */
860 static int
861 msdosfs_link(ap)
862 	struct vop_link_args /* {
863 		struct vnode *a_tdvp;
864 		struct vnode *a_vp;
865 		struct componentname *a_cnp;
866 	} */ *ap;
867 {
868 	return (EOPNOTSUPP);
869 }
870 
871 /*
872  * Renames on files require moving the denode to a new hash queue since the
873  * denode's location is used to compute which hash queue to put the file
874  * in. Unless it is a rename in place.  For example "mv a b".
875  *
876  * What follows is the basic algorithm:
877  *
878  * if (file move) {
879  *	if (dest file exists) {
880  *		remove dest file
881  *	}
882  *	if (dest and src in same directory) {
883  *		rewrite name in existing directory slot
884  *	} else {
885  *		write new entry in dest directory
886  *		update offset and dirclust in denode
887  *		move denode to new hash chain
888  *		clear old directory entry
889  *	}
890  * } else {
891  *	directory move
892  *	if (dest directory exists) {
893  *		if (dest is not empty) {
894  *			return ENOTEMPTY
895  *		}
896  *		remove dest directory
897  *	}
898  *	if (dest and src in same directory) {
899  *		rewrite name in existing entry
900  *	} else {
901  *		be sure dest is not a child of src directory
902  *		write entry in dest directory
903  *		update "." and ".." in moved directory
904  *		clear old directory entry for moved directory
905  *	}
906  * }
907  *
908  * On entry:
909  *	source's parent directory is unlocked
910  *	source file or directory is unlocked
911  *	destination's parent directory is locked
912  *	destination file or directory is locked if it exists
913  *
914  * On exit:
915  *	all denodes should be released
916  */
917 static int
918 msdosfs_rename(ap)
919 	struct vop_rename_args /* {
920 		struct vnode *a_fdvp;
921 		struct vnode *a_fvp;
922 		struct componentname *a_fcnp;
923 		struct vnode *a_tdvp;
924 		struct vnode *a_tvp;
925 		struct componentname *a_tcnp;
926 	} */ *ap;
927 {
928 	struct vnode *tdvp = ap->a_tdvp;
929 	struct vnode *fvp = ap->a_fvp;
930 	struct vnode *fdvp = ap->a_fdvp;
931 	struct vnode *tvp = ap->a_tvp;
932 	struct componentname *tcnp = ap->a_tcnp;
933 	struct componentname *fcnp = ap->a_fcnp;
934 	struct thread *td = fcnp->cn_thread;
935 	struct denode *ip, *xp, *dp, *zp;
936 	u_char toname[11], oldname[11];
937 	u_long from_diroffset, to_diroffset;
938 	u_char to_count;
939 	int doingdirectory = 0, newparent = 0;
940 	int error;
941 	u_long cn;
942 	daddr_t bn;
943 	struct denode *fddep;	/* from file's parent directory	 */
944 	struct denode *fdep;	/* from file or directory	 */
945 	struct denode *tddep;	/* to file's parent directory	 */
946 	struct denode *tdep;	/* to file or directory		 */
947 	struct msdosfsmount *pmp;
948 	struct direntry *dotdotp;
949 	struct buf *bp;
950 
951 	fddep = VTODE(ap->a_fdvp);
952 	fdep = VTODE(ap->a_fvp);
953 	tddep = VTODE(ap->a_tdvp);
954 	tdep = tvp ? VTODE(tvp) : NULL;
955 	pmp = fddep->de_pmp;
956 
957 	pmp = VFSTOMSDOSFS(fdvp->v_mount);
958 
959 #ifdef DIAGNOSTIC
960 	if ((tcnp->cn_flags & HASBUF) == 0 ||
961 	    (fcnp->cn_flags & HASBUF) == 0)
962 		panic("msdosfs_rename: no name");
963 #endif
964 	/*
965 	 * Check for cross-device rename.
966 	 */
967 	if ((fvp->v_mount != tdvp->v_mount) ||
968 	    (tvp && (fvp->v_mount != tvp->v_mount))) {
969 		error = EXDEV;
970 abortit:
971 		if (tdvp == tvp)
972 			vrele(tdvp);
973 		else
974 			vput(tdvp);
975 		if (tvp)
976 			vput(tvp);
977 		vrele(fdvp);
978 		vrele(fvp);
979 		return (error);
980 	}
981 
982 	/*
983 	 * If source and dest are the same, do nothing.
984 	 */
985 	if (tvp == fvp) {
986 		error = 0;
987 		goto abortit;
988 	}
989 
990 	error = vn_lock(fvp, LK_EXCLUSIVE, td);
991 	if (error)
992 		goto abortit;
993 	dp = VTODE(fdvp);
994 	ip = VTODE(fvp);
995 
996 	/*
997 	 * Be sure we are not renaming ".", "..", or an alias of ".". This
998 	 * leads to a crippled directory tree.  It's pretty tough to do a
999 	 * "ls" or "pwd" with the "." directory entry missing, and "cd .."
1000 	 * doesn't work if the ".." entry is missing.
1001 	 */
1002 	if (ip->de_Attributes & ATTR_DIRECTORY) {
1003 		/*
1004 		 * Avoid ".", "..", and aliases of "." for obvious reasons.
1005 		 */
1006 		if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
1007 		    dp == ip ||
1008 		    (fcnp->cn_flags & ISDOTDOT) ||
1009 		    (tcnp->cn_flags & ISDOTDOT) ||
1010 		    (ip->de_flag & DE_RENAME)) {
1011 			VOP_UNLOCK(fvp, 0, td);
1012 			error = EINVAL;
1013 			goto abortit;
1014 		}
1015 		ip->de_flag |= DE_RENAME;
1016 		doingdirectory++;
1017 	}
1018 
1019 	/*
1020 	 * When the target exists, both the directory
1021 	 * and target vnodes are returned locked.
1022 	 */
1023 	dp = VTODE(tdvp);
1024 	xp = tvp ? VTODE(tvp) : NULL;
1025 	/*
1026 	 * Remember direntry place to use for destination
1027 	 */
1028 	to_diroffset = dp->de_fndoffset;
1029 	to_count = dp->de_fndcnt;
1030 
1031 	/*
1032 	 * If ".." must be changed (ie the directory gets a new
1033 	 * parent) then the source directory must not be in the
1034 	 * directory heirarchy above the target, as this would
1035 	 * orphan everything below the source directory. Also
1036 	 * the user must have write permission in the source so
1037 	 * as to be able to change "..". We must repeat the call
1038 	 * to namei, as the parent directory is unlocked by the
1039 	 * call to doscheckpath().
1040 	 */
1041 	error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_thread);
1042 	VOP_UNLOCK(fvp, 0, td);
1043 	if (VTODE(fdvp)->de_StartCluster != VTODE(tdvp)->de_StartCluster)
1044 		newparent = 1;
1045 	if (doingdirectory && newparent) {
1046 		if (error)	/* write access check above */
1047 			goto bad;
1048 		if (xp != NULL)
1049 			vput(tvp);
1050 		/*
1051 		 * doscheckpath() vput()'s dp,
1052 		 * so we have to do a relookup afterwards
1053 		 */
1054 		error = doscheckpath(ip, dp);
1055 		if (error)
1056 			goto out;
1057 		if ((tcnp->cn_flags & SAVESTART) == 0)
1058 			panic("msdosfs_rename: lost to startdir");
1059 		error = relookup(tdvp, &tvp, tcnp);
1060 		if (error)
1061 			goto out;
1062 		dp = VTODE(tdvp);
1063 		xp = tvp ? VTODE(tvp) : NULL;
1064 	}
1065 
1066 	if (xp != NULL) {
1067 		/*
1068 		 * Target must be empty if a directory and have no links
1069 		 * to it. Also, ensure source and target are compatible
1070 		 * (both directories, or both not directories).
1071 		 */
1072 		if (xp->de_Attributes & ATTR_DIRECTORY) {
1073 			if (!dosdirempty(xp)) {
1074 				error = ENOTEMPTY;
1075 				goto bad;
1076 			}
1077 			if (!doingdirectory) {
1078 				error = ENOTDIR;
1079 				goto bad;
1080 			}
1081 			cache_purge(tdvp);
1082 		} else if (doingdirectory) {
1083 			error = EISDIR;
1084 			goto bad;
1085 		}
1086 		error = removede(dp, xp);
1087 		if (error)
1088 			goto bad;
1089 		vput(tvp);
1090 		xp = NULL;
1091 	}
1092 
1093 	/*
1094 	 * Convert the filename in tcnp into a dos filename. We copy this
1095 	 * into the denode and directory entry for the destination
1096 	 * file/directory.
1097 	 */
1098 	error = uniqdosname(VTODE(tdvp), tcnp, toname);
1099 	if (error)
1100 		goto abortit;
1101 
1102 	/*
1103 	 * Since from wasn't locked at various places above,
1104 	 * have to do a relookup here.
1105 	 */
1106 	fcnp->cn_flags &= ~MODMASK;
1107 	fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
1108 	if ((fcnp->cn_flags & SAVESTART) == 0)
1109 		panic("msdosfs_rename: lost from startdir");
1110 	if (!newparent)
1111 		VOP_UNLOCK(tdvp, 0, td);
1112 	if (relookup(fdvp, &fvp, fcnp) == 0)
1113 		vrele(fdvp);
1114 	if (fvp == NULL) {
1115 		/*
1116 		 * From name has disappeared.
1117 		 */
1118 		if (doingdirectory)
1119 			panic("rename: lost dir entry");
1120 		vrele(ap->a_fvp);
1121 		if (newparent)
1122 			VOP_UNLOCK(tdvp, 0, td);
1123 		vrele(tdvp);
1124 		return 0;
1125 	}
1126 	xp = VTODE(fvp);
1127 	zp = VTODE(fdvp);
1128 	from_diroffset = zp->de_fndoffset;
1129 
1130 	/*
1131 	 * Ensure that the directory entry still exists and has not
1132 	 * changed till now. If the source is a file the entry may
1133 	 * have been unlinked or renamed. In either case there is
1134 	 * no further work to be done. If the source is a directory
1135 	 * then it cannot have been rmdir'ed or renamed; this is
1136 	 * prohibited by the DE_RENAME flag.
1137 	 */
1138 	if (xp != ip) {
1139 		if (doingdirectory)
1140 			panic("rename: lost dir entry");
1141 		vrele(ap->a_fvp);
1142 		VOP_UNLOCK(fvp, 0, td);
1143 		if (newparent)
1144 			VOP_UNLOCK(fdvp, 0, td);
1145 		xp = NULL;
1146 	} else {
1147 		vrele(fvp);
1148 		xp = NULL;
1149 
1150 		/*
1151 		 * First write a new entry in the destination
1152 		 * directory and mark the entry in the source directory
1153 		 * as deleted.  Then move the denode to the correct hash
1154 		 * chain for its new location in the filesystem.  And, if
1155 		 * we moved a directory, then update its .. entry to point
1156 		 * to the new parent directory.
1157 		 */
1158 		bcopy(ip->de_Name, oldname, 11);
1159 		bcopy(toname, ip->de_Name, 11);	/* update denode */
1160 		dp->de_fndoffset = to_diroffset;
1161 		dp->de_fndcnt = to_count;
1162 		error = createde(ip, dp, (struct denode **)0, tcnp);
1163 		if (error) {
1164 			bcopy(oldname, ip->de_Name, 11);
1165 			if (newparent)
1166 				VOP_UNLOCK(fdvp, 0, td);
1167 			VOP_UNLOCK(fvp, 0, td);
1168 			goto bad;
1169 		}
1170 		ip->de_refcnt++;
1171 		zp->de_fndoffset = from_diroffset;
1172 		error = removede(zp, ip);
1173 		if (error) {
1174 			/* XXX should really panic here, fs is corrupt */
1175 			if (newparent)
1176 				VOP_UNLOCK(fdvp, 0, td);
1177 			VOP_UNLOCK(fvp, 0, td);
1178 			goto bad;
1179 		}
1180 		if (!doingdirectory) {
1181 			error = pcbmap(dp, de_cluster(pmp, to_diroffset), 0,
1182 				       &ip->de_dirclust, 0);
1183 			if (error) {
1184 				/* XXX should really panic here, fs is corrupt */
1185 				if (newparent)
1186 					VOP_UNLOCK(fdvp, 0, td);
1187 				VOP_UNLOCK(fvp, 0, td);
1188 				goto bad;
1189 			}
1190 			if (ip->de_dirclust == MSDOSFSROOT)
1191 				ip->de_diroffset = to_diroffset;
1192 			else
1193 				ip->de_diroffset = to_diroffset & pmp->pm_crbomask;
1194 		}
1195 		reinsert(ip);
1196 		if (newparent)
1197 			VOP_UNLOCK(fdvp, 0, td);
1198 	}
1199 
1200 	/*
1201 	 * If we moved a directory to a new parent directory, then we must
1202 	 * fixup the ".." entry in the moved directory.
1203 	 */
1204 	if (doingdirectory && newparent) {
1205 		cn = ip->de_StartCluster;
1206 		if (cn == MSDOSFSROOT) {
1207 			/* this should never happen */
1208 			panic("msdosfs_rename(): updating .. in root directory?");
1209 		} else
1210 			bn = cntobn(pmp, cn);
1211 		error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
1212 			      NOCRED, &bp);
1213 		if (error) {
1214 			/* XXX should really panic here, fs is corrupt */
1215 			brelse(bp);
1216 			VOP_UNLOCK(fvp, 0, td);
1217 			goto bad;
1218 		}
1219 		dotdotp = (struct direntry *)bp->b_data + 1;
1220 		putushort(dotdotp->deStartCluster, dp->de_StartCluster);
1221 		if (FAT32(pmp))
1222 			putushort(dotdotp->deHighClust, dp->de_StartCluster >> 16);
1223 		error = bwrite(bp);
1224 		if (error) {
1225 			/* XXX should really panic here, fs is corrupt */
1226 			VOP_UNLOCK(fvp, 0, td);
1227 			goto bad;
1228 		}
1229 	}
1230 
1231 	VOP_UNLOCK(fvp, 0, td);
1232 bad:
1233 	if (xp)
1234 		vput(tvp);
1235 	vput(tdvp);
1236 out:
1237 	ip->de_flag &= ~DE_RENAME;
1238 	vrele(fdvp);
1239 	vrele(fvp);
1240 	return (error);
1241 
1242 }
1243 
1244 static struct {
1245 	struct direntry dot;
1246 	struct direntry dotdot;
1247 } dosdirtemplate = {
1248 	{	".       ", "   ",			/* the . entry */
1249 		ATTR_DIRECTORY,				/* file attribute */
1250 		0,	 				/* reserved */
1251 		0, { 0, 0 }, { 0, 0 },			/* create time & date */
1252 		{ 0, 0 },				/* access date */
1253 		{ 0, 0 },				/* high bits of start cluster */
1254 		{ 210, 4 }, { 210, 4 },			/* modify time & date */
1255 		{ 0, 0 },				/* startcluster */
1256 		{ 0, 0, 0, 0 } 				/* filesize */
1257 	},
1258 	{	"..      ", "   ",			/* the .. entry */
1259 		ATTR_DIRECTORY,				/* file attribute */
1260 		0,	 				/* reserved */
1261 		0, { 0, 0 }, { 0, 0 },			/* create time & date */
1262 		{ 0, 0 },				/* access date */
1263 		{ 0, 0 },				/* high bits of start cluster */
1264 		{ 210, 4 }, { 210, 4 },			/* modify time & date */
1265 		{ 0, 0 },				/* startcluster */
1266 		{ 0, 0, 0, 0 }				/* filesize */
1267 	}
1268 };
1269 
1270 static int
1271 msdosfs_mkdir(ap)
1272 	struct vop_mkdir_args /* {
1273 		struct vnode *a_dvp;
1274 		struvt vnode **a_vpp;
1275 		struvt componentname *a_cnp;
1276 		struct vattr *a_vap;
1277 	} */ *ap;
1278 {
1279 	struct componentname *cnp = ap->a_cnp;
1280 	struct denode *dep;
1281 	struct denode *pdep = VTODE(ap->a_dvp);
1282 	struct direntry *denp;
1283 	struct msdosfsmount *pmp = pdep->de_pmp;
1284 	struct buf *bp;
1285 	u_long newcluster, pcl;
1286 	int bn;
1287 	int error;
1288 	struct denode ndirent;
1289 	struct timespec ts;
1290 
1291 	/*
1292 	 * If this is the root directory and there is no space left we
1293 	 * can't do anything.  This is because the root directory can not
1294 	 * change size.
1295 	 */
1296 	if (pdep->de_StartCluster == MSDOSFSROOT
1297 	    && pdep->de_fndoffset >= pdep->de_FileSize) {
1298 		error = ENOSPC;
1299 		goto bad2;
1300 	}
1301 
1302 	/*
1303 	 * Allocate a cluster to hold the about to be created directory.
1304 	 */
1305 	error = clusteralloc(pmp, 0, 1, CLUST_EOFE, &newcluster, NULL);
1306 	if (error)
1307 		goto bad2;
1308 
1309 	bzero(&ndirent, sizeof(ndirent));
1310 	ndirent.de_pmp = pmp;
1311 	ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
1312 	getnanotime(&ts);
1313 	DETIMES(&ndirent, &ts, &ts, &ts);
1314 
1315 	/*
1316 	 * Now fill the cluster with the "." and ".." entries. And write
1317 	 * the cluster to disk.  This way it is there for the parent
1318 	 * directory to be pointing at if there were a crash.
1319 	 */
1320 	bn = cntobn(pmp, newcluster);
1321 	/* always succeeds */
1322 	bp = getblk(pmp->pm_devvp, bn, pmp->pm_bpcluster, 0, 0);
1323 	bzero(bp->b_data, pmp->pm_bpcluster);
1324 	bcopy(&dosdirtemplate, bp->b_data, sizeof dosdirtemplate);
1325 	denp = (struct direntry *)bp->b_data;
1326 	putushort(denp[0].deStartCluster, newcluster);
1327 	putushort(denp[0].deCDate, ndirent.de_CDate);
1328 	putushort(denp[0].deCTime, ndirent.de_CTime);
1329 	denp[0].deCHundredth = ndirent.de_CHun;
1330 	putushort(denp[0].deADate, ndirent.de_ADate);
1331 	putushort(denp[0].deMDate, ndirent.de_MDate);
1332 	putushort(denp[0].deMTime, ndirent.de_MTime);
1333 	pcl = pdep->de_StartCluster;
1334 	if (FAT32(pmp) && pcl == pmp->pm_rootdirblk)
1335 		pcl = 0;
1336 	putushort(denp[1].deStartCluster, pcl);
1337 	putushort(denp[1].deCDate, ndirent.de_CDate);
1338 	putushort(denp[1].deCTime, ndirent.de_CTime);
1339 	denp[1].deCHundredth = ndirent.de_CHun;
1340 	putushort(denp[1].deADate, ndirent.de_ADate);
1341 	putushort(denp[1].deMDate, ndirent.de_MDate);
1342 	putushort(denp[1].deMTime, ndirent.de_MTime);
1343 	if (FAT32(pmp)) {
1344 		putushort(denp[0].deHighClust, newcluster >> 16);
1345 		putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16);
1346 	}
1347 
1348 	error = bwrite(bp);
1349 	if (error)
1350 		goto bad;
1351 
1352 	/*
1353 	 * Now build up a directory entry pointing to the newly allocated
1354 	 * cluster.  This will be written to an empty slot in the parent
1355 	 * directory.
1356 	 */
1357 #ifdef DIAGNOSTIC
1358 	if ((cnp->cn_flags & HASBUF) == 0)
1359 		panic("msdosfs_mkdir: no name");
1360 #endif
1361 	error = uniqdosname(pdep, cnp, ndirent.de_Name);
1362 	if (error)
1363 		goto bad;
1364 
1365 	ndirent.de_Attributes = ATTR_DIRECTORY;
1366 	ndirent.de_LowerCase = 0;
1367 	ndirent.de_StartCluster = newcluster;
1368 	ndirent.de_FileSize = 0;
1369 	ndirent.de_dev = pdep->de_dev;
1370 	ndirent.de_devvp = pdep->de_devvp;
1371 	error = createde(&ndirent, pdep, &dep, cnp);
1372 	if (error)
1373 		goto bad;
1374 	*ap->a_vpp = DETOV(dep);
1375 	return (0);
1376 
1377 bad:
1378 	clusterfree(pmp, newcluster, NULL);
1379 bad2:
1380 	return (error);
1381 }
1382 
1383 static int
1384 msdosfs_rmdir(ap)
1385 	struct vop_rmdir_args /* {
1386 		struct vnode *a_dvp;
1387 		struct vnode *a_vp;
1388 		struct componentname *a_cnp;
1389 	} */ *ap;
1390 {
1391 	register struct vnode *vp = ap->a_vp;
1392 	register struct vnode *dvp = ap->a_dvp;
1393 	register struct componentname *cnp = ap->a_cnp;
1394 	register struct denode *ip, *dp;
1395 	struct thread *td = cnp->cn_thread;
1396 	int error;
1397 
1398 	ip = VTODE(vp);
1399 	dp = VTODE(dvp);
1400 
1401 	/*
1402 	 * Verify the directory is empty (and valid).
1403 	 * (Rmdir ".." won't be valid since
1404 	 *  ".." will contain a reference to
1405 	 *  the current directory and thus be
1406 	 *  non-empty.)
1407 	 */
1408 	error = 0;
1409 	if (!dosdirempty(ip) || ip->de_flag & DE_RENAME) {
1410 		error = ENOTEMPTY;
1411 		goto out;
1412 	}
1413 	/*
1414 	 * Delete the entry from the directory.  For dos filesystems this
1415 	 * gets rid of the directory entry on disk, the in memory copy
1416 	 * still exists but the de_refcnt is <= 0.  This prevents it from
1417 	 * being found by deget().  When the vput() on dep is done we give
1418 	 * up access and eventually msdosfs_reclaim() will be called which
1419 	 * will remove it from the denode cache.
1420 	 */
1421 	error = removede(dp, ip);
1422 	if (error)
1423 		goto out;
1424 	/*
1425 	 * This is where we decrement the link count in the parent
1426 	 * directory.  Since dos filesystems don't do this we just purge
1427 	 * the name cache.
1428 	 */
1429 	cache_purge(dvp);
1430 	VOP_UNLOCK(dvp, 0, td);
1431 	/*
1432 	 * Truncate the directory that is being deleted.
1433 	 */
1434 	error = detrunc(ip, (u_long)0, IO_SYNC, cnp->cn_cred, td);
1435 	cache_purge(vp);
1436 
1437 	vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
1438 out:
1439 	return (error);
1440 }
1441 
1442 /*
1443  * DOS filesystems don't know what symlinks are.
1444  */
1445 static int
1446 msdosfs_symlink(ap)
1447 	struct vop_symlink_args /* {
1448 		struct vnode *a_dvp;
1449 		struct vnode **a_vpp;
1450 		struct componentname *a_cnp;
1451 		struct vattr *a_vap;
1452 		char *a_target;
1453 	} */ *ap;
1454 {
1455 	return (EOPNOTSUPP);
1456 }
1457 
1458 static int
1459 msdosfs_readdir(ap)
1460 	struct vop_readdir_args /* {
1461 		struct vnode *a_vp;
1462 		struct uio *a_uio;
1463 		struct ucred *a_cred;
1464 		int *a_eofflag;
1465 		int *a_ncookies;
1466 		u_long **a_cookies;
1467 	} */ *ap;
1468 {
1469 	int error = 0;
1470 	int diff;
1471 	long n;
1472 	int blsize;
1473 	long on;
1474 	u_long cn;
1475 	u_long fileno;
1476 	u_long dirsperblk;
1477 	long bias = 0;
1478 	daddr_t bn, lbn;
1479 	struct buf *bp;
1480 	struct denode *dep = VTODE(ap->a_vp);
1481 	struct msdosfsmount *pmp = dep->de_pmp;
1482 	struct direntry *dentp;
1483 	struct dirent dirbuf;
1484 	struct uio *uio = ap->a_uio;
1485 	u_long *cookies = NULL;
1486 	int ncookies = 0;
1487 	off_t offset, off;
1488 	int chksum = -1;
1489 
1490 #ifdef MSDOSFS_DEBUG
1491 	printf("msdosfs_readdir(): vp %p, uio %p, cred %p, eofflagp %p\n",
1492 	    ap->a_vp, uio, ap->a_cred, ap->a_eofflag);
1493 #endif
1494 
1495 	/*
1496 	 * msdosfs_readdir() won't operate properly on regular files since
1497 	 * it does i/o only with the the filesystem vnode, and hence can
1498 	 * retrieve the wrong block from the buffer cache for a plain file.
1499 	 * So, fail attempts to readdir() on a plain file.
1500 	 */
1501 	if ((dep->de_Attributes & ATTR_DIRECTORY) == 0)
1502 		return (ENOTDIR);
1503 
1504 	/*
1505 	 * To be safe, initialize dirbuf
1506 	 */
1507 	bzero(dirbuf.d_name, sizeof(dirbuf.d_name));
1508 
1509 	/*
1510 	 * If the user buffer is smaller than the size of one dos directory
1511 	 * entry or the file offset is not a multiple of the size of a
1512 	 * directory entry, then we fail the read.
1513 	 */
1514 	off = offset = uio->uio_offset;
1515 	if (uio->uio_resid < sizeof(struct direntry) ||
1516 	    (offset & (sizeof(struct direntry) - 1)))
1517 		return (EINVAL);
1518 
1519 	if (ap->a_ncookies) {
1520 		ncookies = uio->uio_resid / 16;
1521 		MALLOC(cookies, u_long *, ncookies * sizeof(u_long), M_TEMP,
1522 		       M_WAITOK);
1523 		*ap->a_cookies = cookies;
1524 		*ap->a_ncookies = ncookies;
1525 	}
1526 
1527 	dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
1528 
1529 	/*
1530 	 * If they are reading from the root directory then, we simulate
1531 	 * the . and .. entries since these don't exist in the root
1532 	 * directory.  We also set the offset bias to make up for having to
1533 	 * simulate these entries. By this I mean that at file offset 64 we
1534 	 * read the first entry in the root directory that lives on disk.
1535 	 */
1536 	if (dep->de_StartCluster == MSDOSFSROOT
1537 	    || (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)) {
1538 #if 0
1539 		printf("msdosfs_readdir(): going after . or .. in root dir, offset %d\n",
1540 		    offset);
1541 #endif
1542 		bias = 2 * sizeof(struct direntry);
1543 		if (offset < bias) {
1544 			for (n = (int)offset / sizeof(struct direntry);
1545 			     n < 2; n++) {
1546 				if (FAT32(pmp))
1547 					dirbuf.d_fileno = cntobn(pmp,
1548 								 pmp->pm_rootdirblk)
1549 							  * dirsperblk;
1550 				else
1551 					dirbuf.d_fileno = 1;
1552 				dirbuf.d_type = DT_DIR;
1553 				switch (n) {
1554 				case 0:
1555 					dirbuf.d_namlen = 1;
1556 					strcpy(dirbuf.d_name, ".");
1557 					break;
1558 				case 1:
1559 					dirbuf.d_namlen = 2;
1560 					strcpy(dirbuf.d_name, "..");
1561 					break;
1562 				}
1563 				dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
1564 				if (uio->uio_resid < dirbuf.d_reclen)
1565 					goto out;
1566 				error = uiomove((caddr_t) &dirbuf,
1567 						dirbuf.d_reclen, uio);
1568 				if (error)
1569 					goto out;
1570 				offset += sizeof(struct direntry);
1571 				off = offset;
1572 				if (cookies) {
1573 					*cookies++ = offset;
1574 					if (--ncookies <= 0)
1575 						goto out;
1576 				}
1577 			}
1578 		}
1579 	}
1580 
1581 	off = offset;
1582 	while (uio->uio_resid > 0) {
1583 		lbn = de_cluster(pmp, offset - bias);
1584 		on = (offset - bias) & pmp->pm_crbomask;
1585 		n = min(pmp->pm_bpcluster - on, uio->uio_resid);
1586 		diff = dep->de_FileSize - (offset - bias);
1587 		if (diff <= 0)
1588 			break;
1589 		n = min(n, diff);
1590 		error = pcbmap(dep, lbn, &bn, &cn, &blsize);
1591 		if (error)
1592 			break;
1593 		error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
1594 		if (error) {
1595 			brelse(bp);
1596 			return (error);
1597 		}
1598 		n = min(n, blsize - bp->b_resid);
1599 
1600 		/*
1601 		 * Convert from dos directory entries to fs-independent
1602 		 * directory entries.
1603 		 */
1604 		for (dentp = (struct direntry *)(bp->b_data + on);
1605 		     (char *)dentp < bp->b_data + on + n;
1606 		     dentp++, offset += sizeof(struct direntry)) {
1607 #if 0
1608 			printf("rd: dentp %08x prev %08x crnt %08x deName %02x attr %02x\n",
1609 			    dentp, prev, crnt, dentp->deName[0], dentp->deAttributes);
1610 #endif
1611 			/*
1612 			 * If this is an unused entry, we can stop.
1613 			 */
1614 			if (dentp->deName[0] == SLOT_EMPTY) {
1615 				brelse(bp);
1616 				goto out;
1617 			}
1618 			/*
1619 			 * Skip deleted entries.
1620 			 */
1621 			if (dentp->deName[0] == SLOT_DELETED) {
1622 				chksum = -1;
1623 				continue;
1624 			}
1625 
1626 			/*
1627 			 * Handle Win95 long directory entries
1628 			 */
1629 			if (dentp->deAttributes == ATTR_WIN95) {
1630 				if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
1631 					continue;
1632 				chksum = win2unixfn((struct winentry *)dentp,
1633 					&dirbuf, chksum,
1634 					pmp->pm_flags & MSDOSFSMNT_U2WTABLE,
1635 					pmp->pm_u2w);
1636 				continue;
1637 			}
1638 
1639 			/*
1640 			 * Skip volume labels
1641 			 */
1642 			if (dentp->deAttributes & ATTR_VOLUME) {
1643 				chksum = -1;
1644 				continue;
1645 			}
1646 			/*
1647 			 * This computation of d_fileno must match
1648 			 * the computation of va_fileid in
1649 			 * msdosfs_getattr.
1650 			 */
1651 			if (dentp->deAttributes & ATTR_DIRECTORY) {
1652 				fileno = getushort(dentp->deStartCluster);
1653 				if (FAT32(pmp))
1654 					fileno |= getushort(dentp->deHighClust) << 16;
1655 				/* if this is the root directory */
1656 				if (fileno == MSDOSFSROOT)
1657 					if (FAT32(pmp))
1658 						fileno = cntobn(pmp,
1659 								pmp->pm_rootdirblk)
1660 							 * dirsperblk;
1661 					else
1662 						fileno = 1;
1663 				else
1664 					fileno = cntobn(pmp, fileno) * dirsperblk;
1665 				dirbuf.d_fileno = fileno;
1666 				dirbuf.d_type = DT_DIR;
1667 			} else {
1668 				dirbuf.d_fileno = offset / sizeof(struct direntry);
1669 				dirbuf.d_type = DT_REG;
1670 			}
1671 			if (chksum != winChksum(dentp->deName))
1672 				dirbuf.d_namlen = dos2unixfn(dentp->deName,
1673 				    (u_char *)dirbuf.d_name,
1674 				    dentp->deLowerCase |
1675 					((pmp->pm_flags & MSDOSFSMNT_SHORTNAME) ?
1676 					(LCASE_BASE | LCASE_EXT) : 0),
1677 				    pmp->pm_flags & MSDOSFSMNT_U2WTABLE,
1678 				    pmp->pm_d2u,
1679 				    pmp->pm_flags & MSDOSFSMNT_ULTABLE,
1680 				    pmp->pm_ul);
1681 			else
1682 				dirbuf.d_name[dirbuf.d_namlen] = 0;
1683 			chksum = -1;
1684 			dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
1685 			if (uio->uio_resid < dirbuf.d_reclen) {
1686 				brelse(bp);
1687 				goto out;
1688 			}
1689 			error = uiomove((caddr_t) &dirbuf,
1690 					dirbuf.d_reclen, uio);
1691 			if (error) {
1692 				brelse(bp);
1693 				goto out;
1694 			}
1695 			if (cookies) {
1696 				*cookies++ = offset + sizeof(struct direntry);
1697 				if (--ncookies <= 0) {
1698 					brelse(bp);
1699 					goto out;
1700 				}
1701 			}
1702 			off = offset + sizeof(struct direntry);
1703 		}
1704 		brelse(bp);
1705 	}
1706 out:
1707 	/* Subtract unused cookies */
1708 	if (ap->a_ncookies)
1709 		*ap->a_ncookies -= ncookies;
1710 
1711 	uio->uio_offset = off;
1712 
1713 	/*
1714 	 * Set the eofflag (NFS uses it)
1715 	 */
1716 	if (ap->a_eofflag) {
1717 		if (dep->de_FileSize - (offset - bias) <= 0)
1718 			*ap->a_eofflag = 1;
1719 		else
1720 			*ap->a_eofflag = 0;
1721 	}
1722 	return (error);
1723 }
1724 
1725 /*
1726  * vp  - address of vnode file the file
1727  * bn  - which cluster we are interested in mapping to a filesystem block number.
1728  * vpp - returns the vnode for the block special file holding the filesystem
1729  *	 containing the file of interest
1730  * bnp - address of where to return the filesystem relative block number
1731  */
1732 static int
1733 msdosfs_bmap(ap)
1734 	struct vop_bmap_args /* {
1735 		struct vnode *a_vp;
1736 		daddr_t a_bn;
1737 		struct vnode **a_vpp;
1738 		daddr_t *a_bnp;
1739 		int *a_runp;
1740 		int *a_runb;
1741 	} */ *ap;
1742 {
1743 	struct denode *dep = VTODE(ap->a_vp);
1744 
1745 	if (ap->a_vpp != NULL)
1746 		*ap->a_vpp = dep->de_devvp;
1747 	if (ap->a_bnp == NULL)
1748 		return (0);
1749 	if (ap->a_runp) {
1750 		/*
1751 		 * Sequential clusters should be counted here.
1752 		 */
1753 		*ap->a_runp = 0;
1754 	}
1755 	if (ap->a_runb) {
1756 		*ap->a_runb = 0;
1757 	}
1758 	return (pcbmap(dep, ap->a_bn, ap->a_bnp, 0, 0));
1759 }
1760 
1761 static int
1762 msdosfs_strategy(ap)
1763 	struct vop_strategy_args /* {
1764 		struct vnode *a_vp;
1765 		struct buf *a_bp;
1766 	} */ *ap;
1767 {
1768 	struct buf *bp = ap->a_bp;
1769 	struct denode *dep = VTODE(bp->b_vp);
1770 	struct vnode *vp;
1771 	int error = 0;
1772 
1773 	if (bp->b_vp->v_type == VBLK || bp->b_vp->v_type == VCHR)
1774 		panic("msdosfs_strategy: spec");
1775 	/*
1776 	 * If we don't already know the filesystem relative block number
1777 	 * then get it using pcbmap().  If pcbmap() returns the block
1778 	 * number as -1 then we've got a hole in the file.  DOS filesystems
1779 	 * don't allow files with holes, so we shouldn't ever see this.
1780 	 */
1781 	if (bp->b_blkno == bp->b_lblkno) {
1782 		error = pcbmap(dep, bp->b_lblkno, &bp->b_blkno, 0, 0);
1783 		if (error) {
1784 			bp->b_error = error;
1785 			bp->b_ioflags |= BIO_ERROR;
1786 			bufdone(bp);
1787 			return (error);
1788 		}
1789 		if ((long)bp->b_blkno == -1)
1790 			vfs_bio_clrbuf(bp);
1791 	}
1792 	if (bp->b_blkno == -1) {
1793 		bufdone(bp);
1794 		return (0);
1795 	}
1796 	/*
1797 	 * Read/write the block from/to the disk that contains the desired
1798 	 * file block.
1799 	 */
1800 	vp = dep->de_devvp;
1801 	bp->b_dev = vp->v_rdev;
1802 	VOP_STRATEGY(vp, bp);
1803 	return (0);
1804 }
1805 
1806 static int
1807 msdosfs_print(ap)
1808 	struct vop_print_args /* {
1809 		struct vnode *vp;
1810 	} */ *ap;
1811 {
1812 	struct denode *dep = VTODE(ap->a_vp);
1813 
1814 	printf(
1815 	    "tag VT_MSDOSFS, startcluster %lu, dircluster %lu, diroffset %lu ",
1816 	       dep->de_StartCluster, dep->de_dirclust, dep->de_diroffset);
1817 	printf(" dev %d, %d", major(dep->de_dev), minor(dep->de_dev));
1818 	lockmgr_printinfo(&ap->a_vp->v_lock);
1819 	printf("\n");
1820 	return (0);
1821 }
1822 
1823 static int
1824 msdosfs_pathconf(ap)
1825 	struct vop_pathconf_args /* {
1826 		struct vnode *a_vp;
1827 		int a_name;
1828 		int *a_retval;
1829 	} */ *ap;
1830 {
1831 	struct msdosfsmount *pmp = VTODE(ap->a_vp)->de_pmp;
1832 
1833 	switch (ap->a_name) {
1834 	case _PC_LINK_MAX:
1835 		*ap->a_retval = 1;
1836 		return (0);
1837 	case _PC_NAME_MAX:
1838 		*ap->a_retval = pmp->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12;
1839 		return (0);
1840 	case _PC_PATH_MAX:
1841 		*ap->a_retval = PATH_MAX;
1842 		return (0);
1843 	case _PC_CHOWN_RESTRICTED:
1844 		*ap->a_retval = 1;
1845 		return (0);
1846 	case _PC_NO_TRUNC:
1847 		*ap->a_retval = 0;
1848 		return (0);
1849 	default:
1850 		return (EINVAL);
1851 	}
1852 	/* NOTREACHED */
1853 }
1854 
1855 
1856 /* Global vfs data structures for msdosfs */
1857 vop_t **msdosfs_vnodeop_p;
1858 static struct vnodeopv_entry_desc msdosfs_vnodeop_entries[] = {
1859 	{ &vop_default_desc,		(vop_t *) vop_defaultop },
1860 	{ &vop_access_desc,		(vop_t *) msdosfs_access },
1861 	{ &vop_bmap_desc,		(vop_t *) msdosfs_bmap },
1862 	{ &vop_cachedlookup_desc,	(vop_t *) msdosfs_lookup },
1863 	{ &vop_close_desc,		(vop_t *) msdosfs_close },
1864 	{ &vop_create_desc,		(vop_t *) msdosfs_create },
1865 	{ &vop_fsync_desc,		(vop_t *) msdosfs_fsync },
1866 	{ &vop_getattr_desc,		(vop_t *) msdosfs_getattr },
1867 	{ &vop_inactive_desc,		(vop_t *) msdosfs_inactive },
1868 	{ &vop_islocked_desc,		(vop_t *) vop_stdislocked },
1869 	{ &vop_link_desc,		(vop_t *) msdosfs_link },
1870 	{ &vop_lock_desc,		(vop_t *) vop_stdlock },
1871 	{ &vop_lookup_desc,		(vop_t *) vfs_cache_lookup },
1872 	{ &vop_mkdir_desc,		(vop_t *) msdosfs_mkdir },
1873 	{ &vop_mknod_desc,		(vop_t *) msdosfs_mknod },
1874 	{ &vop_pathconf_desc,		(vop_t *) msdosfs_pathconf },
1875 	{ &vop_print_desc,		(vop_t *) msdosfs_print },
1876 	{ &vop_read_desc,		(vop_t *) msdosfs_read },
1877 	{ &vop_readdir_desc,		(vop_t *) msdosfs_readdir },
1878 	{ &vop_reclaim_desc,		(vop_t *) msdosfs_reclaim },
1879 	{ &vop_remove_desc,		(vop_t *) msdosfs_remove },
1880 	{ &vop_rename_desc,		(vop_t *) msdosfs_rename },
1881 	{ &vop_rmdir_desc,		(vop_t *) msdosfs_rmdir },
1882 	{ &vop_setattr_desc,		(vop_t *) msdosfs_setattr },
1883 	{ &vop_strategy_desc,		(vop_t *) msdosfs_strategy },
1884 	{ &vop_symlink_desc,		(vop_t *) msdosfs_symlink },
1885 	{ &vop_unlock_desc,		(vop_t *) vop_stdunlock },
1886 	{ &vop_write_desc,		(vop_t *) msdosfs_write },
1887 	{ NULL, NULL }
1888 };
1889 static struct vnodeopv_desc msdosfs_vnodeop_opv_desc =
1890 	{ &msdosfs_vnodeop_p, msdosfs_vnodeop_entries };
1891 
1892 VNODEOP_SET(msdosfs_vnodeop_opv_desc);
1893