xref: /freebsd/sys/fs/msdosfs/msdosfs_vnops.c (revision 71fe318b852b8dfb3e799cb12ef184750f7f8eac)
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(struct vop_create_args *);
85 static int msdosfs_mknod(struct vop_mknod_args *);
86 static int msdosfs_close(struct vop_close_args *);
87 static int msdosfs_access(struct vop_access_args *);
88 static int msdosfs_getattr(struct vop_getattr_args *);
89 static int msdosfs_setattr(struct vop_setattr_args *);
90 static int msdosfs_read(struct vop_read_args *);
91 static int msdosfs_write(struct vop_write_args *);
92 static int msdosfs_fsync(struct vop_fsync_args *);
93 static int msdosfs_remove(struct vop_remove_args *);
94 static int msdosfs_link(struct vop_link_args *);
95 static int msdosfs_rename(struct vop_rename_args *);
96 static int msdosfs_mkdir(struct vop_mkdir_args *);
97 static int msdosfs_rmdir(struct vop_rmdir_args *);
98 static int msdosfs_symlink(struct vop_symlink_args *);
99 static int msdosfs_readdir(struct vop_readdir_args *);
100 static int msdosfs_bmap(struct vop_bmap_args *);
101 static int msdosfs_strategy(struct vop_strategy_args *);
102 static int msdosfs_print(struct vop_print_args *);
103 static int msdosfs_pathconf(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 	VI_LOCK(vp);
222 	if (vp->v_usecount > 1) {
223 		getnanotime(&ts);
224 		DETIMES(dep, &ts, &ts, &ts);
225 	}
226 	VI_UNLOCK(vp);
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 filesystems;
250 	 * unless the file is a socket, fifo, or a block or
251 	 * character device resident on the filesystem.
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_cred(cred, 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 filesystem attempts it a lot.
392 		 */
393 		if (suser_cred(cred, 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_cred(cred, 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 filesystems;
429 		 * unless the file is a socket, fifo, or a block or
430 		 * character device resident on the filesystem.
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_cred(cred, 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 				dep->de_flag &= ~DE_ACCESS;
460 				unix2dostime(&vap->va_atime, &dep->de_ADate,
461 				    NULL, NULL);
462 			}
463 			if (vap->va_mtime.tv_sec != VNOVAL) {
464 				dep->de_flag &= ~DE_UPDATE;
465 				unix2dostime(&vap->va_mtime, &dep->de_MDate,
466 				    &dep->de_MTime, NULL);
467 			}
468 			dep->de_Attributes |= ATTR_ARCHIVE;
469 			dep->de_flag |= DE_MODIFIED;
470 		}
471 	}
472 	/*
473 	 * DOS files only have the ability to have their writability
474 	 * attribute set, so we use the owner write bit to set the readonly
475 	 * attribute.
476 	 */
477 	if (vap->va_mode != (mode_t)VNOVAL) {
478 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
479 			return (EROFS);
480 		if (cred->cr_uid != pmp->pm_uid &&
481 		    (error = suser_cred(cred, PRISON_ROOT)))
482 			return (error);
483 		if (vp->v_type != VDIR) {
484 			/* We ignore the read and execute bits. */
485 			if (vap->va_mode & VWRITE)
486 				dep->de_Attributes &= ~ATTR_READONLY;
487 			else
488 				dep->de_Attributes |= ATTR_READONLY;
489 			dep->de_Attributes |= ATTR_ARCHIVE;
490 			dep->de_flag |= DE_MODIFIED;
491 		}
492 	}
493 	return (deupdat(dep, 1));
494 }
495 
496 static int
497 msdosfs_read(ap)
498 	struct vop_read_args /* {
499 		struct vnode *a_vp;
500 		struct uio *a_uio;
501 		int a_ioflag;
502 		struct ucred *a_cred;
503 	} */ *ap;
504 {
505 	int error = 0;
506 	int blsize;
507 	int isadir;
508 	int orig_resid;
509 	u_int n;
510 	u_long diff;
511 	u_long on;
512 	daddr_t lbn;
513 	daddr_t rablock;
514 	int rasize;
515 	int seqcount;
516 	struct buf *bp;
517 	struct vnode *vp = ap->a_vp;
518 	struct denode *dep = VTODE(vp);
519 	struct msdosfsmount *pmp = dep->de_pmp;
520 	struct uio *uio = ap->a_uio;
521 
522 	if (uio->uio_offset < 0)
523 		return (EINVAL);
524 
525 	if ((uoff_t)uio->uio_offset > DOS_FILESIZE_MAX)
526                 return (0);
527 	/*
528 	 * If they didn't ask for any data, then we are done.
529 	 */
530 	orig_resid = uio->uio_resid;
531 	if (orig_resid <= 0)
532 		return (0);
533 
534 	seqcount = ap->a_ioflag >> 16;
535 
536 	isadir = dep->de_Attributes & ATTR_DIRECTORY;
537 	do {
538 		if (uio->uio_offset >= dep->de_FileSize)
539 			break;
540 		lbn = de_cluster(pmp, uio->uio_offset);
541 		/*
542 		 * If we are operating on a directory file then be sure to
543 		 * do i/o with the vnode for the filesystem instead of the
544 		 * vnode for the directory.
545 		 */
546 		if (isadir) {
547 			/* convert cluster # to block # */
548 			error = pcbmap(dep, lbn, &lbn, 0, &blsize);
549 			if (error == E2BIG) {
550 				error = EINVAL;
551 				break;
552 			} else if (error)
553 				break;
554 			error = bread(pmp->pm_devvp, lbn, blsize, NOCRED, &bp);
555 		} else {
556 			blsize = pmp->pm_bpcluster;
557 			rablock = lbn + 1;
558 			if (seqcount > 1 &&
559 			    de_cn2off(pmp, rablock) < dep->de_FileSize) {
560 				rasize = pmp->pm_bpcluster;
561 				error = breadn(vp, lbn, blsize,
562 				    &rablock, &rasize, 1, NOCRED, &bp);
563 			} else {
564 				error = bread(vp, lbn, blsize, NOCRED, &bp);
565 			}
566 		}
567 		if (error) {
568 			brelse(bp);
569 			break;
570 		}
571 		on = uio->uio_offset & pmp->pm_crbomask;
572 		diff = pmp->pm_bpcluster - on;
573 		n = diff > uio->uio_resid ? uio->uio_resid : diff;
574 		diff = dep->de_FileSize - uio->uio_offset;
575 		if (diff < n)
576 			n = diff;
577 		diff = blsize - bp->b_resid;
578 		if (diff < n)
579 			n = diff;
580 		error = uiomove(bp->b_data + on, (int) n, uio);
581 		brelse(bp);
582 	} while (error == 0 && uio->uio_resid > 0 && n != 0);
583 	if (!isadir && (error == 0 || uio->uio_resid != orig_resid) &&
584 	    (vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
585 		dep->de_flag |= DE_ACCESS;
586 	return (error);
587 }
588 
589 /*
590  * Write data to a file or directory.
591  */
592 static int
593 msdosfs_write(ap)
594 	struct vop_write_args /* {
595 		struct vnode *a_vp;
596 		struct uio *a_uio;
597 		int a_ioflag;
598 		struct ucred *a_cred;
599 	} */ *ap;
600 {
601 	int n;
602 	int croffset;
603 	int resid;
604 	u_long osize;
605 	int error = 0;
606 	u_long count;
607 	daddr_t bn, lastcn;
608 	struct buf *bp;
609 	int ioflag = ap->a_ioflag;
610 	struct uio *uio = ap->a_uio;
611 	struct thread *td = uio->uio_td;
612 	struct vnode *vp = ap->a_vp;
613 	struct vnode *thisvp;
614 	struct denode *dep = VTODE(vp);
615 	struct msdosfsmount *pmp = dep->de_pmp;
616 	struct ucred *cred = ap->a_cred;
617 
618 #ifdef MSDOSFS_DEBUG
619 	printf("msdosfs_write(vp %p, uio %p, ioflag %x, cred %p\n",
620 	    vp, uio, ioflag, cred);
621 	printf("msdosfs_write(): diroff %lu, dirclust %lu, startcluster %lu\n",
622 	    dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster);
623 #endif
624 
625 	switch (vp->v_type) {
626 	case VREG:
627 		if (ioflag & IO_APPEND)
628 			uio->uio_offset = dep->de_FileSize;
629 		thisvp = vp;
630 		break;
631 	case VDIR:
632 		return EISDIR;
633 	default:
634 		panic("msdosfs_write(): bad file type");
635 	}
636 
637 	if (uio->uio_offset < 0)
638 		return (EFBIG);
639 
640 	if (uio->uio_resid == 0)
641 		return (0);
642 
643 	/*
644 	 * If they've exceeded their filesize limit, tell them about it.
645 	 */
646 	if (td &&
647 	    ((uoff_t)uio->uio_offset + uio->uio_resid >
648 	    td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur)) {
649 		PROC_LOCK(td->td_proc);
650 		psignal(td->td_proc, SIGXFSZ);
651 		PROC_UNLOCK(td->td_proc);
652 		return (EFBIG);
653 	}
654 
655 	if ((uoff_t)uio->uio_offset + uio->uio_resid > DOS_FILESIZE_MAX)
656                 return (EFBIG);
657 
658 	/*
659 	 * If the offset we are starting the write at is beyond the end of
660 	 * the file, then they've done a seek.  Unix filesystems allow
661 	 * files with holes in them, DOS doesn't so we must fill the hole
662 	 * with zeroed blocks.
663 	 */
664 	if (uio->uio_offset > dep->de_FileSize) {
665 		error = deextend(dep, uio->uio_offset, cred);
666 		if (error)
667 			return (error);
668 	}
669 
670 	/*
671 	 * Remember some values in case the write fails.
672 	 */
673 	resid = uio->uio_resid;
674 	osize = dep->de_FileSize;
675 
676 	/*
677 	 * If we write beyond the end of the file, extend it to its ultimate
678 	 * size ahead of the time to hopefully get a contiguous area.
679 	 */
680 	if (uio->uio_offset + resid > osize) {
681 		count = de_clcount(pmp, uio->uio_offset + resid) -
682 			de_clcount(pmp, osize);
683 		error = extendfile(dep, count, NULL, NULL, 0);
684 		if (error &&  (error != ENOSPC || (ioflag & IO_UNIT)))
685 			goto errexit;
686 		lastcn = dep->de_fc[FC_LASTFC].fc_frcn;
687 	} else
688 		lastcn = de_clcount(pmp, osize) - 1;
689 
690 	do {
691 		if (de_cluster(pmp, uio->uio_offset) > lastcn) {
692 			error = ENOSPC;
693 			break;
694 		}
695 
696 		croffset = uio->uio_offset & pmp->pm_crbomask;
697 		n = min(uio->uio_resid, pmp->pm_bpcluster - croffset);
698 		if (uio->uio_offset + n > dep->de_FileSize) {
699 			dep->de_FileSize = uio->uio_offset + n;
700 			/* The object size needs to be set before buffer is allocated */
701 			vnode_pager_setsize(vp, dep->de_FileSize);
702 		}
703 
704 		bn = de_cluster(pmp, uio->uio_offset);
705 		if ((uio->uio_offset & pmp->pm_crbomask) == 0
706 		    && (de_cluster(pmp, uio->uio_offset + uio->uio_resid)
707 		        > de_cluster(pmp, uio->uio_offset)
708 			|| uio->uio_offset + uio->uio_resid >= dep->de_FileSize)) {
709 			/*
710 			 * If either the whole cluster gets written,
711 			 * or we write the cluster from its start beyond EOF,
712 			 * then no need to read data from disk.
713 			 */
714 			bp = getblk(thisvp, bn, pmp->pm_bpcluster, 0, 0);
715 			clrbuf(bp);
716 			/*
717 			 * Do the bmap now, since pcbmap needs buffers
718 			 * for the fat table. (see msdosfs_strategy)
719 			 */
720 			if (bp->b_blkno == bp->b_lblkno) {
721 				error = pcbmap(dep, bp->b_lblkno, &bn, 0, 0);
722 				if (error)
723 					bp->b_blkno = -1;
724 				else
725 					bp->b_blkno = bn;
726 			}
727 			if (bp->b_blkno == -1) {
728 				brelse(bp);
729 				if (!error)
730 					error = EIO;		/* XXX */
731 				break;
732 			}
733 		} else {
734 			/*
735 			 * The block we need to write into exists, so read it in.
736 			 */
737 			error = bread(thisvp, bn, pmp->pm_bpcluster, cred, &bp);
738 			if (error) {
739 				brelse(bp);
740 				break;
741 			}
742 		}
743 
744 		/*
745 		 * Should these vnode_pager_* functions be done on dir
746 		 * files?
747 		 */
748 
749 		/*
750 		 * Copy the data from user space into the buf header.
751 		 */
752 		error = uiomove(bp->b_data + croffset, n, uio);
753 		if (error) {
754 			brelse(bp);
755 			break;
756 		}
757 
758 		/*
759 		 * If they want this synchronous then write it and wait for
760 		 * it.  Otherwise, if on a cluster boundary write it
761 		 * asynchronously so we can move on to the next block
762 		 * without delay.  Otherwise do a delayed write because we
763 		 * may want to write somemore into the block later.
764 		 */
765 		if (ioflag & IO_SYNC)
766 			(void) bwrite(bp);
767 		else if (n + croffset == pmp->pm_bpcluster)
768 			bawrite(bp);
769 		else
770 			bdwrite(bp);
771 		dep->de_flag |= DE_UPDATE;
772 	} while (error == 0 && uio->uio_resid > 0);
773 
774 	/*
775 	 * If the write failed and they want us to, truncate the file back
776 	 * to the size it was before the write was attempted.
777 	 */
778 errexit:
779 	if (error) {
780 		if (ioflag & IO_UNIT) {
781 			detrunc(dep, osize, ioflag & IO_SYNC, NOCRED, NULL);
782 			uio->uio_offset -= resid - uio->uio_resid;
783 			uio->uio_resid = resid;
784 		} else {
785 			detrunc(dep, dep->de_FileSize, ioflag & IO_SYNC, NOCRED, NULL);
786 			if (uio->uio_resid != resid)
787 				error = 0;
788 		}
789 	} else if (ioflag & IO_SYNC)
790 		error = deupdat(dep, 1);
791 	return (error);
792 }
793 
794 /*
795  * Flush the blocks of a file to disk.
796  *
797  * This function is worthless for vnodes that represent directories. Maybe we
798  * could just do a sync if they try an fsync on a directory file.
799  */
800 static int
801 msdosfs_fsync(ap)
802 	struct vop_fsync_args /* {
803 		struct vnode *a_vp;
804 		struct ucred *a_cred;
805 		int a_waitfor;
806 		struct thread *a_td;
807 	} */ *ap;
808 {
809 	struct vnode *vp = ap->a_vp;
810 	int s;
811 	struct buf *bp, *nbp;
812 
813 	/*
814 	 * Flush all dirty buffers associated with a vnode.
815 	 */
816 loop:
817 	s = splbio();
818 	VI_LOCK(vp);
819 	for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
820 		nbp = TAILQ_NEXT(bp, b_vnbufs);
821 		VI_UNLOCK(vp);
822 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
823 			VI_LOCK(vp);
824 			continue;
825 		}
826 		if ((bp->b_flags & B_DELWRI) == 0)
827 			panic("msdosfs_fsync: not dirty");
828 		bremfree(bp);
829 		splx(s);
830 		/* XXX Could do bawrite */
831 		(void) bwrite(bp);
832 		goto loop;
833 	}
834 	while (vp->v_numoutput) {
835 		vp->v_iflag |= VI_BWAIT;
836 		(void) msleep((caddr_t)&vp->v_numoutput, VI_MTX(vp),
837 		    PRIBIO + 1, "msdosfsn", 0);
838 	}
839 #ifdef DIAGNOSTIC
840 	if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
841 		vprint("msdosfs_fsync: dirty", vp);
842 		goto loop;
843 	}
844 #endif
845 	VI_UNLOCK(vp);
846 	splx(s);
847 	return (deupdat(VTODE(vp), ap->a_waitfor == MNT_WAIT));
848 }
849 
850 static int
851 msdosfs_remove(ap)
852 	struct vop_remove_args /* {
853 		struct vnode *a_dvp;
854 		struct vnode *a_vp;
855 		struct componentname *a_cnp;
856 	} */ *ap;
857 {
858 	struct denode *dep = VTODE(ap->a_vp);
859 	struct denode *ddep = VTODE(ap->a_dvp);
860 	int error;
861 
862 	if (ap->a_vp->v_type == VDIR)
863 		error = EPERM;
864 	else
865 		error = removede(ddep, dep);
866 #ifdef MSDOSFS_DEBUG
867 	printf("msdosfs_remove(), dep %p, v_usecount %d\n", dep, ap->a_vp->v_usecount);
868 #endif
869 	return (error);
870 }
871 
872 /*
873  * DOS filesystems don't know what links are.
874  */
875 static int
876 msdosfs_link(ap)
877 	struct vop_link_args /* {
878 		struct vnode *a_tdvp;
879 		struct vnode *a_vp;
880 		struct componentname *a_cnp;
881 	} */ *ap;
882 {
883 	return (EOPNOTSUPP);
884 }
885 
886 /*
887  * Renames on files require moving the denode to a new hash queue since the
888  * denode's location is used to compute which hash queue to put the file
889  * in. Unless it is a rename in place.  For example "mv a b".
890  *
891  * What follows is the basic algorithm:
892  *
893  * if (file move) {
894  *	if (dest file exists) {
895  *		remove dest file
896  *	}
897  *	if (dest and src in same directory) {
898  *		rewrite name in existing directory slot
899  *	} else {
900  *		write new entry in dest directory
901  *		update offset and dirclust in denode
902  *		move denode to new hash chain
903  *		clear old directory entry
904  *	}
905  * } else {
906  *	directory move
907  *	if (dest directory exists) {
908  *		if (dest is not empty) {
909  *			return ENOTEMPTY
910  *		}
911  *		remove dest directory
912  *	}
913  *	if (dest and src in same directory) {
914  *		rewrite name in existing entry
915  *	} else {
916  *		be sure dest is not a child of src directory
917  *		write entry in dest directory
918  *		update "." and ".." in moved directory
919  *		clear old directory entry for moved directory
920  *	}
921  * }
922  *
923  * On entry:
924  *	source's parent directory is unlocked
925  *	source file or directory is unlocked
926  *	destination's parent directory is locked
927  *	destination file or directory is locked if it exists
928  *
929  * On exit:
930  *	all denodes should be released
931  */
932 static int
933 msdosfs_rename(ap)
934 	struct vop_rename_args /* {
935 		struct vnode *a_fdvp;
936 		struct vnode *a_fvp;
937 		struct componentname *a_fcnp;
938 		struct vnode *a_tdvp;
939 		struct vnode *a_tvp;
940 		struct componentname *a_tcnp;
941 	} */ *ap;
942 {
943 	struct vnode *tdvp = ap->a_tdvp;
944 	struct vnode *fvp = ap->a_fvp;
945 	struct vnode *fdvp = ap->a_fdvp;
946 	struct vnode *tvp = ap->a_tvp;
947 	struct componentname *tcnp = ap->a_tcnp;
948 	struct componentname *fcnp = ap->a_fcnp;
949 	struct thread *td = fcnp->cn_thread;
950 	struct denode *ip, *xp, *dp, *zp;
951 	u_char toname[11], oldname[11];
952 	u_long from_diroffset, to_diroffset;
953 	u_char to_count;
954 	int doingdirectory = 0, newparent = 0;
955 	int error;
956 	u_long cn;
957 	daddr_t bn;
958 	struct denode *fddep;	/* from file's parent directory	 */
959 	struct denode *fdep;	/* from file or directory	 */
960 	struct denode *tddep;	/* to file's parent directory	 */
961 	struct denode *tdep;	/* to file or directory		 */
962 	struct msdosfsmount *pmp;
963 	struct direntry *dotdotp;
964 	struct buf *bp;
965 
966 	fddep = VTODE(ap->a_fdvp);
967 	fdep = VTODE(ap->a_fvp);
968 	tddep = VTODE(ap->a_tdvp);
969 	tdep = tvp ? VTODE(tvp) : NULL;
970 	pmp = fddep->de_pmp;
971 
972 	pmp = VFSTOMSDOSFS(fdvp->v_mount);
973 
974 #ifdef DIAGNOSTIC
975 	if ((tcnp->cn_flags & HASBUF) == 0 ||
976 	    (fcnp->cn_flags & HASBUF) == 0)
977 		panic("msdosfs_rename: no name");
978 #endif
979 	/*
980 	 * Check for cross-device rename.
981 	 */
982 	if ((fvp->v_mount != tdvp->v_mount) ||
983 	    (tvp && (fvp->v_mount != tvp->v_mount))) {
984 		error = EXDEV;
985 abortit:
986 		if (tdvp == tvp)
987 			vrele(tdvp);
988 		else
989 			vput(tdvp);
990 		if (tvp)
991 			vput(tvp);
992 		vrele(fdvp);
993 		vrele(fvp);
994 		return (error);
995 	}
996 
997 	/*
998 	 * If source and dest are the same, do nothing.
999 	 */
1000 	if (tvp == fvp) {
1001 		error = 0;
1002 		goto abortit;
1003 	}
1004 
1005 	error = vn_lock(fvp, LK_EXCLUSIVE, td);
1006 	if (error)
1007 		goto abortit;
1008 	dp = VTODE(fdvp);
1009 	ip = VTODE(fvp);
1010 
1011 	/*
1012 	 * Be sure we are not renaming ".", "..", or an alias of ".". This
1013 	 * leads to a crippled directory tree.  It's pretty tough to do a
1014 	 * "ls" or "pwd" with the "." directory entry missing, and "cd .."
1015 	 * doesn't work if the ".." entry is missing.
1016 	 */
1017 	if (ip->de_Attributes & ATTR_DIRECTORY) {
1018 		/*
1019 		 * Avoid ".", "..", and aliases of "." for obvious reasons.
1020 		 */
1021 		if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
1022 		    dp == ip ||
1023 		    (fcnp->cn_flags & ISDOTDOT) ||
1024 		    (tcnp->cn_flags & ISDOTDOT) ||
1025 		    (ip->de_flag & DE_RENAME)) {
1026 			VOP_UNLOCK(fvp, 0, td);
1027 			error = EINVAL;
1028 			goto abortit;
1029 		}
1030 		ip->de_flag |= DE_RENAME;
1031 		doingdirectory++;
1032 	}
1033 
1034 	/*
1035 	 * When the target exists, both the directory
1036 	 * and target vnodes are returned locked.
1037 	 */
1038 	dp = VTODE(tdvp);
1039 	xp = tvp ? VTODE(tvp) : NULL;
1040 	/*
1041 	 * Remember direntry place to use for destination
1042 	 */
1043 	to_diroffset = dp->de_fndoffset;
1044 	to_count = dp->de_fndcnt;
1045 
1046 	/*
1047 	 * If ".." must be changed (ie the directory gets a new
1048 	 * parent) then the source directory must not be in the
1049 	 * directory heirarchy above the target, as this would
1050 	 * orphan everything below the source directory. Also
1051 	 * the user must have write permission in the source so
1052 	 * as to be able to change "..". We must repeat the call
1053 	 * to namei, as the parent directory is unlocked by the
1054 	 * call to doscheckpath().
1055 	 */
1056 	error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_thread);
1057 	VOP_UNLOCK(fvp, 0, td);
1058 	if (VTODE(fdvp)->de_StartCluster != VTODE(tdvp)->de_StartCluster)
1059 		newparent = 1;
1060 	if (doingdirectory && newparent) {
1061 		if (error)	/* write access check above */
1062 			goto bad;
1063 		if (xp != NULL)
1064 			vput(tvp);
1065 		/*
1066 		 * doscheckpath() vput()'s dp,
1067 		 * so we have to do a relookup afterwards
1068 		 */
1069 		error = doscheckpath(ip, dp);
1070 		if (error)
1071 			goto out;
1072 		if ((tcnp->cn_flags & SAVESTART) == 0)
1073 			panic("msdosfs_rename: lost to startdir");
1074 		error = relookup(tdvp, &tvp, tcnp);
1075 		if (error)
1076 			goto out;
1077 		dp = VTODE(tdvp);
1078 		xp = tvp ? VTODE(tvp) : NULL;
1079 	}
1080 
1081 	if (xp != NULL) {
1082 		/*
1083 		 * Target must be empty if a directory and have no links
1084 		 * to it. Also, ensure source and target are compatible
1085 		 * (both directories, or both not directories).
1086 		 */
1087 		if (xp->de_Attributes & ATTR_DIRECTORY) {
1088 			if (!dosdirempty(xp)) {
1089 				error = ENOTEMPTY;
1090 				goto bad;
1091 			}
1092 			if (!doingdirectory) {
1093 				error = ENOTDIR;
1094 				goto bad;
1095 			}
1096 			cache_purge(tdvp);
1097 		} else if (doingdirectory) {
1098 			error = EISDIR;
1099 			goto bad;
1100 		}
1101 		error = removede(dp, xp);
1102 		if (error)
1103 			goto bad;
1104 		vput(tvp);
1105 		xp = NULL;
1106 	}
1107 
1108 	/*
1109 	 * Convert the filename in tcnp into a dos filename. We copy this
1110 	 * into the denode and directory entry for the destination
1111 	 * file/directory.
1112 	 */
1113 	error = uniqdosname(VTODE(tdvp), tcnp, toname);
1114 	if (error)
1115 		goto abortit;
1116 
1117 	/*
1118 	 * Since from wasn't locked at various places above,
1119 	 * have to do a relookup here.
1120 	 */
1121 	fcnp->cn_flags &= ~MODMASK;
1122 	fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
1123 	if ((fcnp->cn_flags & SAVESTART) == 0)
1124 		panic("msdosfs_rename: lost from startdir");
1125 	if (!newparent)
1126 		VOP_UNLOCK(tdvp, 0, td);
1127 	if (relookup(fdvp, &fvp, fcnp) == 0)
1128 		vrele(fdvp);
1129 	if (fvp == NULL) {
1130 		/*
1131 		 * From name has disappeared.
1132 		 */
1133 		if (doingdirectory)
1134 			panic("rename: lost dir entry");
1135 		vrele(ap->a_fvp);
1136 		if (newparent)
1137 			VOP_UNLOCK(tdvp, 0, td);
1138 		vrele(tdvp);
1139 		return 0;
1140 	}
1141 	xp = VTODE(fvp);
1142 	zp = VTODE(fdvp);
1143 	from_diroffset = zp->de_fndoffset;
1144 
1145 	/*
1146 	 * Ensure that the directory entry still exists and has not
1147 	 * changed till now. If the source is a file the entry may
1148 	 * have been unlinked or renamed. In either case there is
1149 	 * no further work to be done. If the source is a directory
1150 	 * then it cannot have been rmdir'ed or renamed; this is
1151 	 * prohibited by the DE_RENAME flag.
1152 	 */
1153 	if (xp != ip) {
1154 		if (doingdirectory)
1155 			panic("rename: lost dir entry");
1156 		vrele(ap->a_fvp);
1157 		VOP_UNLOCK(fvp, 0, td);
1158 		if (newparent)
1159 			VOP_UNLOCK(fdvp, 0, td);
1160 		xp = NULL;
1161 	} else {
1162 		vrele(fvp);
1163 		xp = NULL;
1164 
1165 		/*
1166 		 * First write a new entry in the destination
1167 		 * directory and mark the entry in the source directory
1168 		 * as deleted.  Then move the denode to the correct hash
1169 		 * chain for its new location in the filesystem.  And, if
1170 		 * we moved a directory, then update its .. entry to point
1171 		 * to the new parent directory.
1172 		 */
1173 		bcopy(ip->de_Name, oldname, 11);
1174 		bcopy(toname, ip->de_Name, 11);	/* update denode */
1175 		dp->de_fndoffset = to_diroffset;
1176 		dp->de_fndcnt = to_count;
1177 		error = createde(ip, dp, (struct denode **)0, tcnp);
1178 		if (error) {
1179 			bcopy(oldname, ip->de_Name, 11);
1180 			if (newparent)
1181 				VOP_UNLOCK(fdvp, 0, td);
1182 			VOP_UNLOCK(fvp, 0, td);
1183 			goto bad;
1184 		}
1185 		ip->de_refcnt++;
1186 		zp->de_fndoffset = from_diroffset;
1187 		error = removede(zp, ip);
1188 		if (error) {
1189 			/* XXX should really panic here, fs is corrupt */
1190 			if (newparent)
1191 				VOP_UNLOCK(fdvp, 0, td);
1192 			VOP_UNLOCK(fvp, 0, td);
1193 			goto bad;
1194 		}
1195 		if (!doingdirectory) {
1196 			error = pcbmap(dp, de_cluster(pmp, to_diroffset), 0,
1197 				       &ip->de_dirclust, 0);
1198 			if (error) {
1199 				/* XXX should really panic here, fs is corrupt */
1200 				if (newparent)
1201 					VOP_UNLOCK(fdvp, 0, td);
1202 				VOP_UNLOCK(fvp, 0, td);
1203 				goto bad;
1204 			}
1205 			if (ip->de_dirclust == MSDOSFSROOT)
1206 				ip->de_diroffset = to_diroffset;
1207 			else
1208 				ip->de_diroffset = to_diroffset & pmp->pm_crbomask;
1209 		}
1210 		reinsert(ip);
1211 		if (newparent)
1212 			VOP_UNLOCK(fdvp, 0, td);
1213 	}
1214 
1215 	/*
1216 	 * If we moved a directory to a new parent directory, then we must
1217 	 * fixup the ".." entry in the moved directory.
1218 	 */
1219 	if (doingdirectory && newparent) {
1220 		cn = ip->de_StartCluster;
1221 		if (cn == MSDOSFSROOT) {
1222 			/* this should never happen */
1223 			panic("msdosfs_rename(): updating .. in root directory?");
1224 		} else
1225 			bn = cntobn(pmp, cn);
1226 		error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
1227 			      NOCRED, &bp);
1228 		if (error) {
1229 			/* XXX should really panic here, fs is corrupt */
1230 			brelse(bp);
1231 			VOP_UNLOCK(fvp, 0, td);
1232 			goto bad;
1233 		}
1234 		dotdotp = (struct direntry *)bp->b_data + 1;
1235 		putushort(dotdotp->deStartCluster, dp->de_StartCluster);
1236 		if (FAT32(pmp))
1237 			putushort(dotdotp->deHighClust, dp->de_StartCluster >> 16);
1238 		error = bwrite(bp);
1239 		if (error) {
1240 			/* XXX should really panic here, fs is corrupt */
1241 			VOP_UNLOCK(fvp, 0, td);
1242 			goto bad;
1243 		}
1244 	}
1245 
1246 	VOP_UNLOCK(fvp, 0, td);
1247 bad:
1248 	if (xp)
1249 		vput(tvp);
1250 	vput(tdvp);
1251 out:
1252 	ip->de_flag &= ~DE_RENAME;
1253 	vrele(fdvp);
1254 	vrele(fvp);
1255 	return (error);
1256 
1257 }
1258 
1259 static struct {
1260 	struct direntry dot;
1261 	struct direntry dotdot;
1262 } dosdirtemplate = {
1263 	{	".       ", "   ",			/* the . entry */
1264 		ATTR_DIRECTORY,				/* file attribute */
1265 		0,	 				/* reserved */
1266 		0, { 0, 0 }, { 0, 0 },			/* create time & date */
1267 		{ 0, 0 },				/* access date */
1268 		{ 0, 0 },				/* high bits of start cluster */
1269 		{ 210, 4 }, { 210, 4 },			/* modify time & date */
1270 		{ 0, 0 },				/* startcluster */
1271 		{ 0, 0, 0, 0 } 				/* filesize */
1272 	},
1273 	{	"..      ", "   ",			/* the .. entry */
1274 		ATTR_DIRECTORY,				/* file attribute */
1275 		0,	 				/* reserved */
1276 		0, { 0, 0 }, { 0, 0 },			/* create time & date */
1277 		{ 0, 0 },				/* access date */
1278 		{ 0, 0 },				/* high bits of start cluster */
1279 		{ 210, 4 }, { 210, 4 },			/* modify time & date */
1280 		{ 0, 0 },				/* startcluster */
1281 		{ 0, 0, 0, 0 }				/* filesize */
1282 	}
1283 };
1284 
1285 static int
1286 msdosfs_mkdir(ap)
1287 	struct vop_mkdir_args /* {
1288 		struct vnode *a_dvp;
1289 		struvt vnode **a_vpp;
1290 		struvt componentname *a_cnp;
1291 		struct vattr *a_vap;
1292 	} */ *ap;
1293 {
1294 	struct componentname *cnp = ap->a_cnp;
1295 	struct denode *dep;
1296 	struct denode *pdep = VTODE(ap->a_dvp);
1297 	struct direntry *denp;
1298 	struct msdosfsmount *pmp = pdep->de_pmp;
1299 	struct buf *bp;
1300 	u_long newcluster, pcl;
1301 	int bn;
1302 	int error;
1303 	struct denode ndirent;
1304 	struct timespec ts;
1305 
1306 	/*
1307 	 * If this is the root directory and there is no space left we
1308 	 * can't do anything.  This is because the root directory can not
1309 	 * change size.
1310 	 */
1311 	if (pdep->de_StartCluster == MSDOSFSROOT
1312 	    && pdep->de_fndoffset >= pdep->de_FileSize) {
1313 		error = ENOSPC;
1314 		goto bad2;
1315 	}
1316 
1317 	/*
1318 	 * Allocate a cluster to hold the about to be created directory.
1319 	 */
1320 	error = clusteralloc(pmp, 0, 1, CLUST_EOFE, &newcluster, NULL);
1321 	if (error)
1322 		goto bad2;
1323 
1324 	bzero(&ndirent, sizeof(ndirent));
1325 	ndirent.de_pmp = pmp;
1326 	ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
1327 	getnanotime(&ts);
1328 	DETIMES(&ndirent, &ts, &ts, &ts);
1329 
1330 	/*
1331 	 * Now fill the cluster with the "." and ".." entries. And write
1332 	 * the cluster to disk.  This way it is there for the parent
1333 	 * directory to be pointing at if there were a crash.
1334 	 */
1335 	bn = cntobn(pmp, newcluster);
1336 	/* always succeeds */
1337 	bp = getblk(pmp->pm_devvp, bn, pmp->pm_bpcluster, 0, 0);
1338 	bzero(bp->b_data, pmp->pm_bpcluster);
1339 	bcopy(&dosdirtemplate, bp->b_data, sizeof dosdirtemplate);
1340 	denp = (struct direntry *)bp->b_data;
1341 	putushort(denp[0].deStartCluster, newcluster);
1342 	putushort(denp[0].deCDate, ndirent.de_CDate);
1343 	putushort(denp[0].deCTime, ndirent.de_CTime);
1344 	denp[0].deCHundredth = ndirent.de_CHun;
1345 	putushort(denp[0].deADate, ndirent.de_ADate);
1346 	putushort(denp[0].deMDate, ndirent.de_MDate);
1347 	putushort(denp[0].deMTime, ndirent.de_MTime);
1348 	pcl = pdep->de_StartCluster;
1349 	if (FAT32(pmp) && pcl == pmp->pm_rootdirblk)
1350 		pcl = 0;
1351 	putushort(denp[1].deStartCluster, pcl);
1352 	putushort(denp[1].deCDate, ndirent.de_CDate);
1353 	putushort(denp[1].deCTime, ndirent.de_CTime);
1354 	denp[1].deCHundredth = ndirent.de_CHun;
1355 	putushort(denp[1].deADate, ndirent.de_ADate);
1356 	putushort(denp[1].deMDate, ndirent.de_MDate);
1357 	putushort(denp[1].deMTime, ndirent.de_MTime);
1358 	if (FAT32(pmp)) {
1359 		putushort(denp[0].deHighClust, newcluster >> 16);
1360 		putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16);
1361 	}
1362 
1363 	error = bwrite(bp);
1364 	if (error)
1365 		goto bad;
1366 
1367 	/*
1368 	 * Now build up a directory entry pointing to the newly allocated
1369 	 * cluster.  This will be written to an empty slot in the parent
1370 	 * directory.
1371 	 */
1372 #ifdef DIAGNOSTIC
1373 	if ((cnp->cn_flags & HASBUF) == 0)
1374 		panic("msdosfs_mkdir: no name");
1375 #endif
1376 	error = uniqdosname(pdep, cnp, ndirent.de_Name);
1377 	if (error)
1378 		goto bad;
1379 
1380 	ndirent.de_Attributes = ATTR_DIRECTORY;
1381 	ndirent.de_LowerCase = 0;
1382 	ndirent.de_StartCluster = newcluster;
1383 	ndirent.de_FileSize = 0;
1384 	ndirent.de_dev = pdep->de_dev;
1385 	ndirent.de_devvp = pdep->de_devvp;
1386 	error = createde(&ndirent, pdep, &dep, cnp);
1387 	if (error)
1388 		goto bad;
1389 	*ap->a_vpp = DETOV(dep);
1390 	return (0);
1391 
1392 bad:
1393 	clusterfree(pmp, newcluster, NULL);
1394 bad2:
1395 	return (error);
1396 }
1397 
1398 static int
1399 msdosfs_rmdir(ap)
1400 	struct vop_rmdir_args /* {
1401 		struct vnode *a_dvp;
1402 		struct vnode *a_vp;
1403 		struct componentname *a_cnp;
1404 	} */ *ap;
1405 {
1406 	register struct vnode *vp = ap->a_vp;
1407 	register struct vnode *dvp = ap->a_dvp;
1408 	register struct componentname *cnp = ap->a_cnp;
1409 	register struct denode *ip, *dp;
1410 	struct thread *td = cnp->cn_thread;
1411 	int error;
1412 
1413 	ip = VTODE(vp);
1414 	dp = VTODE(dvp);
1415 
1416 	/*
1417 	 * Verify the directory is empty (and valid).
1418 	 * (Rmdir ".." won't be valid since
1419 	 *  ".." will contain a reference to
1420 	 *  the current directory and thus be
1421 	 *  non-empty.)
1422 	 */
1423 	error = 0;
1424 	if (!dosdirempty(ip) || ip->de_flag & DE_RENAME) {
1425 		error = ENOTEMPTY;
1426 		goto out;
1427 	}
1428 	/*
1429 	 * Delete the entry from the directory.  For dos filesystems this
1430 	 * gets rid of the directory entry on disk, the in memory copy
1431 	 * still exists but the de_refcnt is <= 0.  This prevents it from
1432 	 * being found by deget().  When the vput() on dep is done we give
1433 	 * up access and eventually msdosfs_reclaim() will be called which
1434 	 * will remove it from the denode cache.
1435 	 */
1436 	error = removede(dp, ip);
1437 	if (error)
1438 		goto out;
1439 	/*
1440 	 * This is where we decrement the link count in the parent
1441 	 * directory.  Since dos filesystems don't do this we just purge
1442 	 * the name cache.
1443 	 */
1444 	cache_purge(dvp);
1445 	VOP_UNLOCK(dvp, 0, td);
1446 	/*
1447 	 * Truncate the directory that is being deleted.
1448 	 */
1449 	error = detrunc(ip, (u_long)0, IO_SYNC, cnp->cn_cred, td);
1450 	cache_purge(vp);
1451 
1452 	vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
1453 out:
1454 	return (error);
1455 }
1456 
1457 /*
1458  * DOS filesystems don't know what symlinks are.
1459  */
1460 static int
1461 msdosfs_symlink(ap)
1462 	struct vop_symlink_args /* {
1463 		struct vnode *a_dvp;
1464 		struct vnode **a_vpp;
1465 		struct componentname *a_cnp;
1466 		struct vattr *a_vap;
1467 		char *a_target;
1468 	} */ *ap;
1469 {
1470 	return (EOPNOTSUPP);
1471 }
1472 
1473 static int
1474 msdosfs_readdir(ap)
1475 	struct vop_readdir_args /* {
1476 		struct vnode *a_vp;
1477 		struct uio *a_uio;
1478 		struct ucred *a_cred;
1479 		int *a_eofflag;
1480 		int *a_ncookies;
1481 		u_long **a_cookies;
1482 	} */ *ap;
1483 {
1484 	int error = 0;
1485 	int diff;
1486 	long n;
1487 	int blsize;
1488 	long on;
1489 	u_long cn;
1490 	u_long fileno;
1491 	u_long dirsperblk;
1492 	long bias = 0;
1493 	daddr_t bn, lbn;
1494 	struct buf *bp;
1495 	struct denode *dep = VTODE(ap->a_vp);
1496 	struct msdosfsmount *pmp = dep->de_pmp;
1497 	struct direntry *dentp;
1498 	struct dirent dirbuf;
1499 	struct uio *uio = ap->a_uio;
1500 	u_long *cookies = NULL;
1501 	int ncookies = 0;
1502 	off_t offset, off;
1503 	int chksum = -1;
1504 
1505 #ifdef MSDOSFS_DEBUG
1506 	printf("msdosfs_readdir(): vp %p, uio %p, cred %p, eofflagp %p\n",
1507 	    ap->a_vp, uio, ap->a_cred, ap->a_eofflag);
1508 #endif
1509 
1510 	/*
1511 	 * msdosfs_readdir() won't operate properly on regular files since
1512 	 * it does i/o only with the the filesystem vnode, and hence can
1513 	 * retrieve the wrong block from the buffer cache for a plain file.
1514 	 * So, fail attempts to readdir() on a plain file.
1515 	 */
1516 	if ((dep->de_Attributes & ATTR_DIRECTORY) == 0)
1517 		return (ENOTDIR);
1518 
1519 	/*
1520 	 * To be safe, initialize dirbuf
1521 	 */
1522 	bzero(dirbuf.d_name, sizeof(dirbuf.d_name));
1523 
1524 	/*
1525 	 * If the user buffer is smaller than the size of one dos directory
1526 	 * entry or the file offset is not a multiple of the size of a
1527 	 * directory entry, then we fail the read.
1528 	 */
1529 	off = offset = uio->uio_offset;
1530 	if (uio->uio_resid < sizeof(struct direntry) ||
1531 	    (offset & (sizeof(struct direntry) - 1)))
1532 		return (EINVAL);
1533 
1534 	if (ap->a_ncookies) {
1535 		ncookies = uio->uio_resid / 16;
1536 		MALLOC(cookies, u_long *, ncookies * sizeof(u_long), M_TEMP,
1537 		       M_WAITOK);
1538 		*ap->a_cookies = cookies;
1539 		*ap->a_ncookies = ncookies;
1540 	}
1541 
1542 	dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
1543 
1544 	/*
1545 	 * If they are reading from the root directory then, we simulate
1546 	 * the . and .. entries since these don't exist in the root
1547 	 * directory.  We also set the offset bias to make up for having to
1548 	 * simulate these entries. By this I mean that at file offset 64 we
1549 	 * read the first entry in the root directory that lives on disk.
1550 	 */
1551 	if (dep->de_StartCluster == MSDOSFSROOT
1552 	    || (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)) {
1553 #if 0
1554 		printf("msdosfs_readdir(): going after . or .. in root dir, offset %d\n",
1555 		    offset);
1556 #endif
1557 		bias = 2 * sizeof(struct direntry);
1558 		if (offset < bias) {
1559 			for (n = (int)offset / sizeof(struct direntry);
1560 			     n < 2; n++) {
1561 				if (FAT32(pmp))
1562 					dirbuf.d_fileno = cntobn(pmp,
1563 								 pmp->pm_rootdirblk)
1564 							  * dirsperblk;
1565 				else
1566 					dirbuf.d_fileno = 1;
1567 				dirbuf.d_type = DT_DIR;
1568 				switch (n) {
1569 				case 0:
1570 					dirbuf.d_namlen = 1;
1571 					strcpy(dirbuf.d_name, ".");
1572 					break;
1573 				case 1:
1574 					dirbuf.d_namlen = 2;
1575 					strcpy(dirbuf.d_name, "..");
1576 					break;
1577 				}
1578 				dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
1579 				if (uio->uio_resid < dirbuf.d_reclen)
1580 					goto out;
1581 				error = uiomove((caddr_t) &dirbuf,
1582 						dirbuf.d_reclen, uio);
1583 				if (error)
1584 					goto out;
1585 				offset += sizeof(struct direntry);
1586 				off = offset;
1587 				if (cookies) {
1588 					*cookies++ = offset;
1589 					if (--ncookies <= 0)
1590 						goto out;
1591 				}
1592 			}
1593 		}
1594 	}
1595 
1596 	off = offset;
1597 	while (uio->uio_resid > 0) {
1598 		lbn = de_cluster(pmp, offset - bias);
1599 		on = (offset - bias) & pmp->pm_crbomask;
1600 		n = min(pmp->pm_bpcluster - on, uio->uio_resid);
1601 		diff = dep->de_FileSize - (offset - bias);
1602 		if (diff <= 0)
1603 			break;
1604 		n = min(n, diff);
1605 		error = pcbmap(dep, lbn, &bn, &cn, &blsize);
1606 		if (error)
1607 			break;
1608 		error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
1609 		if (error) {
1610 			brelse(bp);
1611 			return (error);
1612 		}
1613 		n = min(n, blsize - bp->b_resid);
1614 
1615 		/*
1616 		 * Convert from dos directory entries to fs-independent
1617 		 * directory entries.
1618 		 */
1619 		for (dentp = (struct direntry *)(bp->b_data + on);
1620 		     (char *)dentp < bp->b_data + on + n;
1621 		     dentp++, offset += sizeof(struct direntry)) {
1622 #if 0
1623 			printf("rd: dentp %08x prev %08x crnt %08x deName %02x attr %02x\n",
1624 			    dentp, prev, crnt, dentp->deName[0], dentp->deAttributes);
1625 #endif
1626 			/*
1627 			 * If this is an unused entry, we can stop.
1628 			 */
1629 			if (dentp->deName[0] == SLOT_EMPTY) {
1630 				brelse(bp);
1631 				goto out;
1632 			}
1633 			/*
1634 			 * Skip deleted entries.
1635 			 */
1636 			if (dentp->deName[0] == SLOT_DELETED) {
1637 				chksum = -1;
1638 				continue;
1639 			}
1640 
1641 			/*
1642 			 * Handle Win95 long directory entries
1643 			 */
1644 			if (dentp->deAttributes == ATTR_WIN95) {
1645 				if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
1646 					continue;
1647 				chksum = win2unixfn((struct winentry *)dentp,
1648 					&dirbuf, chksum,
1649 					pmp->pm_flags & MSDOSFSMNT_U2WTABLE,
1650 					pmp->pm_u2w);
1651 				continue;
1652 			}
1653 
1654 			/*
1655 			 * Skip volume labels
1656 			 */
1657 			if (dentp->deAttributes & ATTR_VOLUME) {
1658 				chksum = -1;
1659 				continue;
1660 			}
1661 			/*
1662 			 * This computation of d_fileno must match
1663 			 * the computation of va_fileid in
1664 			 * msdosfs_getattr.
1665 			 */
1666 			if (dentp->deAttributes & ATTR_DIRECTORY) {
1667 				fileno = getushort(dentp->deStartCluster);
1668 				if (FAT32(pmp))
1669 					fileno |= getushort(dentp->deHighClust) << 16;
1670 				/* if this is the root directory */
1671 				if (fileno == MSDOSFSROOT)
1672 					if (FAT32(pmp))
1673 						fileno = cntobn(pmp,
1674 								pmp->pm_rootdirblk)
1675 							 * dirsperblk;
1676 					else
1677 						fileno = 1;
1678 				else
1679 					fileno = cntobn(pmp, fileno) * dirsperblk;
1680 				dirbuf.d_fileno = fileno;
1681 				dirbuf.d_type = DT_DIR;
1682 			} else {
1683 				dirbuf.d_fileno = offset / sizeof(struct direntry);
1684 				dirbuf.d_type = DT_REG;
1685 			}
1686 			if (chksum != winChksum(dentp->deName))
1687 				dirbuf.d_namlen = dos2unixfn(dentp->deName,
1688 				    (u_char *)dirbuf.d_name,
1689 				    dentp->deLowerCase |
1690 					((pmp->pm_flags & MSDOSFSMNT_SHORTNAME) ?
1691 					(LCASE_BASE | LCASE_EXT) : 0),
1692 				    pmp->pm_flags & MSDOSFSMNT_U2WTABLE,
1693 				    pmp->pm_d2u,
1694 				    pmp->pm_flags & MSDOSFSMNT_ULTABLE,
1695 				    pmp->pm_ul);
1696 			else
1697 				dirbuf.d_name[dirbuf.d_namlen] = 0;
1698 			chksum = -1;
1699 			dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
1700 			if (uio->uio_resid < dirbuf.d_reclen) {
1701 				brelse(bp);
1702 				goto out;
1703 			}
1704 			error = uiomove((caddr_t) &dirbuf,
1705 					dirbuf.d_reclen, uio);
1706 			if (error) {
1707 				brelse(bp);
1708 				goto out;
1709 			}
1710 			if (cookies) {
1711 				*cookies++ = offset + sizeof(struct direntry);
1712 				if (--ncookies <= 0) {
1713 					brelse(bp);
1714 					goto out;
1715 				}
1716 			}
1717 			off = offset + sizeof(struct direntry);
1718 		}
1719 		brelse(bp);
1720 	}
1721 out:
1722 	/* Subtract unused cookies */
1723 	if (ap->a_ncookies)
1724 		*ap->a_ncookies -= ncookies;
1725 
1726 	uio->uio_offset = off;
1727 
1728 	/*
1729 	 * Set the eofflag (NFS uses it)
1730 	 */
1731 	if (ap->a_eofflag) {
1732 		if (dep->de_FileSize - (offset - bias) <= 0)
1733 			*ap->a_eofflag = 1;
1734 		else
1735 			*ap->a_eofflag = 0;
1736 	}
1737 	return (error);
1738 }
1739 
1740 /*
1741  * vp  - address of vnode file the file
1742  * bn  - which cluster we are interested in mapping to a filesystem block number.
1743  * vpp - returns the vnode for the block special file holding the filesystem
1744  *	 containing the file of interest
1745  * bnp - address of where to return the filesystem relative block number
1746  */
1747 static int
1748 msdosfs_bmap(ap)
1749 	struct vop_bmap_args /* {
1750 		struct vnode *a_vp;
1751 		daddr_t a_bn;
1752 		struct vnode **a_vpp;
1753 		daddr_t *a_bnp;
1754 		int *a_runp;
1755 		int *a_runb;
1756 	} */ *ap;
1757 {
1758 	struct denode *dep = VTODE(ap->a_vp);
1759 	daddr_t blkno;
1760 	int error;
1761 
1762 	if (ap->a_vpp != NULL)
1763 		*ap->a_vpp = dep->de_devvp;
1764 	if (ap->a_bnp == NULL)
1765 		return (0);
1766 	if (ap->a_runp) {
1767 		/*
1768 		 * Sequential clusters should be counted here.
1769 		 */
1770 		*ap->a_runp = 0;
1771 	}
1772 	if (ap->a_runb) {
1773 		*ap->a_runb = 0;
1774 	}
1775 	error = pcbmap(dep, ap->a_bn, &blkno, 0, 0);
1776 	*ap->a_bnp = blkno;
1777 	return (error);
1778 }
1779 
1780 static int
1781 msdosfs_strategy(ap)
1782 	struct vop_strategy_args /* {
1783 		struct vnode *a_vp;
1784 		struct buf *a_bp;
1785 	} */ *ap;
1786 {
1787 	struct buf *bp = ap->a_bp;
1788 	struct denode *dep = VTODE(bp->b_vp);
1789 	struct vnode *vp;
1790 	int error = 0;
1791 	daddr_t blkno;
1792 
1793 	if (bp->b_vp->v_type == VBLK || bp->b_vp->v_type == VCHR)
1794 		panic("msdosfs_strategy: spec");
1795 	/*
1796 	 * If we don't already know the filesystem relative block number
1797 	 * then get it using pcbmap().  If pcbmap() returns the block
1798 	 * number as -1 then we've got a hole in the file.  DOS filesystems
1799 	 * don't allow files with holes, so we shouldn't ever see this.
1800 	 */
1801 	if (bp->b_blkno == bp->b_lblkno) {
1802 		error = pcbmap(dep, bp->b_lblkno, &blkno, 0, 0);
1803 		bp->b_blkno = blkno;
1804 		if (error) {
1805 			bp->b_error = error;
1806 			bp->b_ioflags |= BIO_ERROR;
1807 			bufdone(bp);
1808 			return (error);
1809 		}
1810 		if ((long)bp->b_blkno == -1)
1811 			vfs_bio_clrbuf(bp);
1812 	}
1813 	if (bp->b_blkno == -1) {
1814 		bufdone(bp);
1815 		return (0);
1816 	}
1817 	/*
1818 	 * Read/write the block from/to the disk that contains the desired
1819 	 * file block.
1820 	 */
1821 	vp = dep->de_devvp;
1822 	bp->b_dev = vp->v_rdev;
1823 	VOP_STRATEGY(vp, bp);
1824 	return (0);
1825 }
1826 
1827 static int
1828 msdosfs_print(ap)
1829 	struct vop_print_args /* {
1830 		struct vnode *vp;
1831 	} */ *ap;
1832 {
1833 	struct denode *dep = VTODE(ap->a_vp);
1834 
1835 	printf("startcluster %lu, dircluster %lu, diroffset %lu, ",
1836 	       dep->de_StartCluster, dep->de_dirclust, dep->de_diroffset);
1837 	printf("on dev (%d, %d)\n", major(dep->de_dev), minor(dep->de_dev));
1838 	return (0);
1839 }
1840 
1841 static int
1842 msdosfs_pathconf(ap)
1843 	struct vop_pathconf_args /* {
1844 		struct vnode *a_vp;
1845 		int a_name;
1846 		int *a_retval;
1847 	} */ *ap;
1848 {
1849 	struct msdosfsmount *pmp = VTODE(ap->a_vp)->de_pmp;
1850 
1851 	switch (ap->a_name) {
1852 	case _PC_LINK_MAX:
1853 		*ap->a_retval = 1;
1854 		return (0);
1855 	case _PC_NAME_MAX:
1856 		*ap->a_retval = pmp->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12;
1857 		return (0);
1858 	case _PC_PATH_MAX:
1859 		*ap->a_retval = PATH_MAX;
1860 		return (0);
1861 	case _PC_CHOWN_RESTRICTED:
1862 		*ap->a_retval = 1;
1863 		return (0);
1864 	case _PC_NO_TRUNC:
1865 		*ap->a_retval = 0;
1866 		return (0);
1867 	default:
1868 		return (EINVAL);
1869 	}
1870 	/* NOTREACHED */
1871 }
1872 
1873 
1874 /* Global vfs data structures for msdosfs */
1875 vop_t **msdosfs_vnodeop_p;
1876 static struct vnodeopv_entry_desc msdosfs_vnodeop_entries[] = {
1877 	{ &vop_default_desc,		(vop_t *) vop_defaultop },
1878 	{ &vop_access_desc,		(vop_t *) msdosfs_access },
1879 	{ &vop_bmap_desc,		(vop_t *) msdosfs_bmap },
1880 	{ &vop_cachedlookup_desc,	(vop_t *) msdosfs_lookup },
1881 	{ &vop_close_desc,		(vop_t *) msdosfs_close },
1882 	{ &vop_create_desc,		(vop_t *) msdosfs_create },
1883 	{ &vop_fsync_desc,		(vop_t *) msdosfs_fsync },
1884 	{ &vop_getattr_desc,		(vop_t *) msdosfs_getattr },
1885 	{ &vop_inactive_desc,		(vop_t *) msdosfs_inactive },
1886 	{ &vop_islocked_desc,		(vop_t *) vop_stdislocked },
1887 	{ &vop_link_desc,		(vop_t *) msdosfs_link },
1888 	{ &vop_lock_desc,		(vop_t *) vop_stdlock },
1889 	{ &vop_lookup_desc,		(vop_t *) vfs_cache_lookup },
1890 	{ &vop_mkdir_desc,		(vop_t *) msdosfs_mkdir },
1891 	{ &vop_mknod_desc,		(vop_t *) msdosfs_mknod },
1892 	{ &vop_pathconf_desc,		(vop_t *) msdosfs_pathconf },
1893 	{ &vop_print_desc,		(vop_t *) msdosfs_print },
1894 	{ &vop_read_desc,		(vop_t *) msdosfs_read },
1895 	{ &vop_readdir_desc,		(vop_t *) msdosfs_readdir },
1896 	{ &vop_reclaim_desc,		(vop_t *) msdosfs_reclaim },
1897 	{ &vop_remove_desc,		(vop_t *) msdosfs_remove },
1898 	{ &vop_rename_desc,		(vop_t *) msdosfs_rename },
1899 	{ &vop_rmdir_desc,		(vop_t *) msdosfs_rmdir },
1900 	{ &vop_setattr_desc,		(vop_t *) msdosfs_setattr },
1901 	{ &vop_strategy_desc,		(vop_t *) msdosfs_strategy },
1902 	{ &vop_symlink_desc,		(vop_t *) msdosfs_symlink },
1903 	{ &vop_unlock_desc,		(vop_t *) vop_stdunlock },
1904 	{ &vop_write_desc,		(vop_t *) msdosfs_write },
1905 	{ NULL, NULL }
1906 };
1907 static struct vnodeopv_desc msdosfs_vnodeop_opv_desc =
1908 	{ &msdosfs_vnodeop_p, msdosfs_vnodeop_entries };
1909 
1910 VNODEOP_SET(msdosfs_vnodeop_opv_desc);
1911