xref: /netbsd-src/sys/fs/msdosfs/msdosfs_vnops.c (revision 274254cdae52594c1aa480a736aef78313d15c9c)
1 /*	$NetBSD: msdosfs_vnops.c,v 1.58 2009/03/14 21:04:23 dsl Exp $	*/
2 
3 /*-
4  * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
5  * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
6  * All rights reserved.
7  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by TooLs GmbH.
20  * 4. The name of TooLs GmbH may not be used to endorse or promote products
21  *    derived from this software without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
28  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
29  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
30  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
31  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
32  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  */
34 /*
35  * Written by Paul Popelka (paulp@uts.amdahl.com)
36  *
37  * You can do anything you want with this software, just don't say you wrote
38  * it, and don't remove this notice.
39  *
40  * This software is provided "as is".
41  *
42  * The author supplies this software to be publicly redistributed on the
43  * understanding that the author is not responsible for the correct
44  * functioning of this software in any circumstances and is not liable for
45  * any damages caused by this software.
46  *
47  * October 1992
48  */
49 
50 #include <sys/cdefs.h>
51 __KERNEL_RCSID(0, "$NetBSD: msdosfs_vnops.c,v 1.58 2009/03/14 21:04:23 dsl Exp $");
52 
53 #include <sys/param.h>
54 #include <sys/systm.h>
55 #include <sys/namei.h>
56 #include <sys/resourcevar.h>	/* defines plimit structure in proc struct */
57 #include <sys/kernel.h>
58 #include <sys/file.h>		/* define FWRITE ... */
59 #include <sys/stat.h>
60 #include <sys/buf.h>
61 #include <sys/proc.h>
62 #include <sys/mount.h>
63 #include <sys/vnode.h>
64 #include <sys/signalvar.h>
65 #include <sys/malloc.h>
66 #include <sys/dirent.h>
67 #include <sys/lockf.h>
68 #include <sys/kauth.h>
69 
70 #include <miscfs/genfs/genfs.h>
71 #include <miscfs/specfs/specdev.h> /* XXX */	/* defines v_rdev */
72 
73 #include <uvm/uvm_extern.h>
74 
75 #include <fs/msdosfs/bpb.h>
76 #include <fs/msdosfs/direntry.h>
77 #include <fs/msdosfs/denode.h>
78 #include <fs/msdosfs/msdosfsmount.h>
79 #include <fs/msdosfs/fat.h>
80 
81 /*
82  * Some general notes:
83  *
84  * In the ufs filesystem the inodes, superblocks, and indirect blocks are
85  * read/written using the vnode for the filesystem. Blocks that represent
86  * the contents of a file are read/written using the vnode for the file
87  * (including directories when they are read/written as files). This
88  * presents problems for the dos filesystem because data that should be in
89  * an inode (if dos had them) resides in the directory itself.  Since we
90  * must update directory entries without the benefit of having the vnode
91  * for the directory we must use the vnode for the filesystem.  This means
92  * that when a directory is actually read/written (via read, write, or
93  * readdir, or seek) we must use the vnode for the filesystem instead of
94  * the vnode for the directory as would happen in ufs. This is to insure we
95  * retrieve the correct block from the buffer cache since the hash value is
96  * based upon the vnode address and the desired block number.
97  */
98 
99 /*
100  * Create a regular file. On entry the directory to contain the file being
101  * created is locked.  We must release before we return. We must also free
102  * the pathname buffer pointed at by cnp->cn_pnbuf, always on error, or
103  * only if the SAVESTART bit in cn_flags is clear on success.
104  */
105 int
106 msdosfs_create(void *v)
107 {
108 	struct vop_create_args /* {
109 		struct vnode *a_dvp;
110 		struct vnode **a_vpp;
111 		struct componentname *a_cnp;
112 		struct vattr *a_vap;
113 	} */ *ap = v;
114 	struct componentname *cnp = ap->a_cnp;
115 	struct denode ndirent;
116 	struct denode *dep;
117 	struct denode *pdep = VTODE(ap->a_dvp);
118 	int error;
119 
120 #ifdef MSDOSFS_DEBUG
121 	printf("msdosfs_create(cnp %p, vap %p\n", cnp, ap->a_vap);
122 #endif
123 
124 	/*
125 	 * If this is the root directory and there is no space left we
126 	 * can't do anything.  This is because the root directory can not
127 	 * change size.
128 	 */
129 	if (pdep->de_StartCluster == MSDOSFSROOT
130 	    && pdep->de_fndoffset >= pdep->de_FileSize) {
131 		error = ENOSPC;
132 		goto bad;
133 	}
134 
135 	/*
136 	 * Create a directory entry for the file, then call createde() to
137 	 * have it installed. NOTE: DOS files are always executable.  We
138 	 * use the absence of the owner write bit to make the file
139 	 * readonly.
140 	 */
141 #ifdef DIAGNOSTIC
142 	if ((cnp->cn_flags & HASBUF) == 0)
143 		panic("msdosfs_create: no name");
144 #endif
145 	memset(&ndirent, 0, sizeof(ndirent));
146 	if ((error = uniqdosname(pdep, cnp, ndirent.de_Name)) != 0)
147 		goto bad;
148 
149 	ndirent.de_Attributes = (ap->a_vap->va_mode & S_IWUSR) ?
150 				ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY;
151 	ndirent.de_StartCluster = 0;
152 	ndirent.de_FileSize = 0;
153 	ndirent.de_dev = pdep->de_dev;
154 	ndirent.de_devvp = pdep->de_devvp;
155 	ndirent.de_pmp = pdep->de_pmp;
156 	ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
157 	DETIMES(&ndirent, NULL, NULL, NULL, pdep->de_pmp->pm_gmtoff);
158 	if ((error = createde(&ndirent, pdep, &dep, cnp)) != 0)
159 		goto bad;
160 	if ((cnp->cn_flags & SAVESTART) == 0)
161 		PNBUF_PUT(cnp->cn_pnbuf);
162 	VN_KNOTE(ap->a_dvp, NOTE_WRITE);
163 	vput(ap->a_dvp);
164 	*ap->a_vpp = DETOV(dep);
165 	return (0);
166 
167 bad:
168 	PNBUF_PUT(cnp->cn_pnbuf);
169 	vput(ap->a_dvp);
170 	return (error);
171 }
172 
173 int
174 msdosfs_mknod(void *v)
175 {
176 	struct vop_mknod_args /* {
177 		struct vnode *a_dvp;
178 		struct vnode **a_vpp;
179 		struct componentname *a_cnp;
180 		struct vattr *a_vap;
181 	} */ *ap = v;
182 
183 	PNBUF_PUT(ap->a_cnp->cn_pnbuf);
184 	vput(ap->a_dvp);
185 	return (EINVAL);
186 }
187 
188 int
189 msdosfs_open(void *v)
190 {
191 #if 0
192 	struct vop_open_args /* {
193 		struct vnode *a_vp;
194 		int a_mode;
195 		kauth_cred_t a_cred;
196 	} */ *ap;
197 #endif
198 
199 	return (0);
200 }
201 
202 int
203 msdosfs_close(void *v)
204 {
205 	struct vop_close_args /* {
206 		struct vnode *a_vp;
207 		int a_fflag;
208 		kauth_cred_t a_cred;
209 	} */ *ap = v;
210 	struct vnode *vp = ap->a_vp;
211 	struct denode *dep = VTODE(vp);
212 
213 	mutex_enter(&vp->v_interlock);
214 	if (vp->v_usecount > 1)
215 		DETIMES(dep, NULL, NULL, NULL, dep->de_pmp->pm_gmtoff);
216 	mutex_exit(&vp->v_interlock);
217 	return (0);
218 }
219 
220 int
221 msdosfs_access(void *v)
222 {
223 	struct vop_access_args /* {
224 		struct vnode *a_vp;
225 		int a_mode;
226 		kauth_cred_t a_cred;
227 	} */ *ap = v;
228 	struct vnode *vp = ap->a_vp;
229 	struct denode *dep = VTODE(vp);
230 	struct msdosfsmount *pmp = dep->de_pmp;
231 	mode_t mode = ap->a_mode;
232 
233 	/*
234 	 * Disallow write attempts on read-only file systems;
235 	 * unless the file is a socket, fifo, or a block or
236 	 * character device resident on the file system.
237 	 */
238 	if (mode & VWRITE) {
239 		switch (vp->v_type) {
240 		case VDIR:
241 		case VLNK:
242 		case VREG:
243 			if (vp->v_mount->mnt_flag & MNT_RDONLY)
244 				return (EROFS);
245 		default:
246 			break;
247 		}
248 	}
249 
250 	if ((dep->de_Attributes & ATTR_READONLY) == 0)
251 		mode = S_IRWXU|S_IRWXG|S_IRWXO;
252 	else
253 		mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
254 	return (vaccess(ap->a_vp->v_type,
255 	    mode & (vp->v_type == VDIR ? pmp->pm_dirmask : pmp->pm_mask),
256 	    pmp->pm_uid, pmp->pm_gid, ap->a_mode, ap->a_cred));
257 }
258 
259 int
260 msdosfs_getattr(void *v)
261 {
262 	struct vop_getattr_args /* {
263 		struct vnode *a_vp;
264 		struct vattr *a_vap;
265 		kauth_cred_t a_cred;
266 	} */ *ap = v;
267 	struct denode *dep = VTODE(ap->a_vp);
268 	struct msdosfsmount *pmp = dep->de_pmp;
269 	struct vattr *vap = ap->a_vap;
270 	mode_t mode;
271 	u_long dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
272 	ino_t fileid;
273 
274 	DETIMES(dep, NULL, NULL, NULL, pmp->pm_gmtoff);
275 	vap->va_fsid = dep->de_dev;
276 	/*
277 	 * The following computation of the fileid must be the same as that
278 	 * used in msdosfs_readdir() to compute d_fileno. If not, pwd
279 	 * doesn't work.
280 	 */
281 	if (dep->de_Attributes & ATTR_DIRECTORY) {
282 		fileid = cntobn(pmp, (ino_t)dep->de_StartCluster) * dirsperblk;
283 		if (dep->de_StartCluster == MSDOSFSROOT)
284 			fileid = 1;
285 	} else {
286 		fileid = cntobn(pmp, (ino_t)dep->de_dirclust) * dirsperblk;
287 		if (dep->de_dirclust == MSDOSFSROOT)
288 			fileid = roottobn(pmp, 0) * dirsperblk;
289 		fileid += dep->de_diroffset / sizeof(struct direntry);
290 	}
291 	vap->va_fileid = fileid;
292 	if ((dep->de_Attributes & ATTR_READONLY) == 0)
293 		mode = S_IRWXU|S_IRWXG|S_IRWXO;
294 	else
295 		mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
296 	vap->va_mode =
297 	    mode & (ap->a_vp->v_type == VDIR ? pmp->pm_dirmask : pmp->pm_mask);
298 	vap->va_uid = pmp->pm_uid;
299 	vap->va_gid = pmp->pm_gid;
300 	vap->va_nlink = 1;
301 	vap->va_rdev = 0;
302 	vap->va_size = ap->a_vp->v_size;
303 	dos2unixtime(dep->de_MDate, dep->de_MTime, 0, pmp->pm_gmtoff,
304 	    &vap->va_mtime);
305 	if (dep->de_pmp->pm_flags & MSDOSFSMNT_LONGNAME) {
306 		dos2unixtime(dep->de_ADate, 0, 0, pmp->pm_gmtoff,
307 		    &vap->va_atime);
308 		dos2unixtime(dep->de_CDate, dep->de_CTime, dep->de_CHun,
309 		    pmp->pm_gmtoff, &vap->va_ctime);
310 	} else {
311 		vap->va_atime = vap->va_mtime;
312 		vap->va_ctime = vap->va_mtime;
313 	}
314 	vap->va_flags = 0;
315 	if ((dep->de_Attributes & ATTR_ARCHIVE) == 0)
316 		vap->va_mode  |= S_ARCH1;
317 	vap->va_gen = 0;
318 	vap->va_blocksize = pmp->pm_bpcluster;
319 	vap->va_bytes =
320 	    (dep->de_FileSize + pmp->pm_crbomask) & ~pmp->pm_crbomask;
321 	vap->va_type = ap->a_vp->v_type;
322 	return (0);
323 }
324 
325 int
326 msdosfs_setattr(void *v)
327 {
328 	struct vop_setattr_args /* {
329 		struct vnode *a_vp;
330 		struct vattr *a_vap;
331 		kauth_cred_t a_cred;
332 	} */ *ap = v;
333 	int error = 0, de_changed = 0;
334 	struct denode *dep = VTODE(ap->a_vp);
335 	struct msdosfsmount *pmp = dep->de_pmp;
336 	struct vnode *vp  = ap->a_vp;
337 	struct vattr *vap = ap->a_vap;
338 	kauth_cred_t cred = ap->a_cred;
339 
340 #ifdef MSDOSFS_DEBUG
341 	printf("msdosfs_setattr(): vp %p, vap %p, cred %p\n",
342 	    ap->a_vp, vap, cred);
343 #endif
344 	/*
345 	 * Note we silently ignore uid or gid changes.
346 	 */
347 	if ((vap->va_type != VNON) || (vap->va_nlink != (nlink_t)VNOVAL) ||
348 	    (vap->va_fsid != VNOVAL) || (vap->va_fileid != VNOVAL) ||
349 	    (vap->va_blocksize != VNOVAL) || (vap->va_rdev != VNOVAL) ||
350 	    (vap->va_bytes != VNOVAL) || (vap->va_gen != VNOVAL) ||
351 	    (vap->va_uid != VNOVAL && vap->va_uid != pmp->pm_uid) ||
352 	    (vap->va_gid != VNOVAL && vap->va_gid != pmp->pm_gid)) {
353 #ifdef MSDOSFS_DEBUG
354 		printf("msdosfs_setattr(): returning EINVAL\n");
355 		printf("    va_type %d, va_nlink %x, va_fsid %"PRIx64", va_fileid %llx\n",
356 		    vap->va_type, vap->va_nlink, vap->va_fsid,
357 		    (unsigned long long)vap->va_fileid);
358 		printf("    va_blocksize %lx, va_rdev %"PRIx64", va_bytes %"PRIx64", va_gen %lx\n",
359 		    vap->va_blocksize, vap->va_rdev, (long long)vap->va_bytes, vap->va_gen);
360 #endif
361 		return (EINVAL);
362 	}
363 	/*
364 	 * Silently ignore attributes modifications on directories.
365 	 */
366 	if (ap->a_vp->v_type == VDIR)
367 		return 0;
368 
369 	if (vap->va_size != VNOVAL) {
370 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
371 			return (EROFS);
372 		error = detrunc(dep, (u_long)vap->va_size, 0, cred);
373 		if (error)
374 			return (error);
375 		de_changed = 1;
376 	}
377 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
378 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
379 			return (EROFS);
380 		if (kauth_cred_geteuid(cred) != pmp->pm_uid &&
381 		    (error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
382 		    NULL)) &&
383 		    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
384 		    (error = VOP_ACCESS(ap->a_vp, VWRITE, cred))))
385 			return (error);
386 		if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) == 0 &&
387 		    vap->va_atime.tv_sec != VNOVAL)
388 			unix2dostime(&vap->va_atime, pmp->pm_gmtoff, &dep->de_ADate, NULL, NULL);
389 		if (vap->va_mtime.tv_sec != VNOVAL)
390 			unix2dostime(&vap->va_mtime, pmp->pm_gmtoff, &dep->de_MDate, &dep->de_MTime, NULL);
391 		dep->de_Attributes |= ATTR_ARCHIVE;
392 		dep->de_flag |= DE_MODIFIED;
393 		de_changed = 1;
394 	}
395 	/*
396 	 * DOS files only have the ability to have their writability
397 	 * attribute set, so we use the owner write bit to set the readonly
398 	 * attribute.
399 	 */
400 	if (vap->va_mode != (mode_t)VNOVAL) {
401 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
402 			return (EROFS);
403 		if (kauth_cred_geteuid(cred) != pmp->pm_uid &&
404 		    (error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
405 		    NULL)))
406 			return (error);
407 		/* We ignore the read and execute bits. */
408 		if (vap->va_mode & S_IWUSR)
409 			dep->de_Attributes &= ~ATTR_READONLY;
410 		else
411 			dep->de_Attributes |= ATTR_READONLY;
412 		dep->de_flag |= DE_MODIFIED;
413 		de_changed = 1;
414 	}
415 	/*
416 	 * Allow the `archived' bit to be toggled.
417 	 */
418 	if (vap->va_flags != VNOVAL) {
419 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
420 			return (EROFS);
421 		if (kauth_cred_geteuid(cred) != pmp->pm_uid &&
422 		    (error = kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER,
423 		    NULL)))
424 			return (error);
425 		if (vap->va_flags & SF_ARCHIVED)
426 			dep->de_Attributes &= ~ATTR_ARCHIVE;
427 		else
428 			dep->de_Attributes |= ATTR_ARCHIVE;
429 		dep->de_flag |= DE_MODIFIED;
430 		de_changed = 1;
431 	}
432 
433 	if (de_changed) {
434 		VN_KNOTE(vp, NOTE_ATTRIB);
435 		return (deupdat(dep, 1));
436 	} else
437 		return (0);
438 }
439 
440 int
441 msdosfs_read(void *v)
442 {
443 	struct vop_read_args /* {
444 		struct vnode *a_vp;
445 		struct uio *a_uio;
446 		int a_ioflag;
447 		kauth_cred_t a_cred;
448 	} */ *ap = v;
449 	int error = 0;
450 	int64_t diff;
451 	int blsize;
452 	long n;
453 	long on;
454 	daddr_t lbn;
455 	vsize_t bytelen;
456 	struct buf *bp;
457 	struct vnode *vp = ap->a_vp;
458 	struct denode *dep = VTODE(vp);
459 	struct msdosfsmount *pmp = dep->de_pmp;
460 	struct uio *uio = ap->a_uio;
461 
462 	/*
463 	 * If they didn't ask for any data, then we are done.
464 	 */
465 
466 	if (uio->uio_resid == 0)
467 		return (0);
468 	if (uio->uio_offset < 0)
469 		return (EINVAL);
470 	if (uio->uio_offset >= dep->de_FileSize)
471 		return (0);
472 
473 	if (vp->v_type == VREG) {
474 		const int advice = IO_ADV_DECODE(ap->a_ioflag);
475 
476 		while (uio->uio_resid > 0) {
477 			bytelen = MIN(dep->de_FileSize - uio->uio_offset,
478 				      uio->uio_resid);
479 
480 			if (bytelen == 0)
481 				break;
482 			error = ubc_uiomove(&vp->v_uobj, uio, bytelen, advice,
483 			    UBC_READ | UBC_PARTIALOK | UBC_UNMAP_FLAG(vp));
484 			if (error)
485 				break;
486 		}
487 		dep->de_flag |= DE_ACCESS;
488 		goto out;
489 	}
490 
491 	/* this loop is only for directories now */
492 	do {
493 		lbn = de_cluster(pmp, uio->uio_offset);
494 		on = uio->uio_offset & pmp->pm_crbomask;
495 		n = MIN(pmp->pm_bpcluster - on, uio->uio_resid);
496 		if (uio->uio_offset >= dep->de_FileSize)
497 			return (0);
498 		/* file size (and hence diff) may be up to 4GB */
499 		diff = dep->de_FileSize - uio->uio_offset;
500 		if (diff < n)
501 			n = (long) diff;
502 
503 		/* convert cluster # to sector # */
504 		error = pcbmap(dep, lbn, &lbn, 0, &blsize);
505 		if (error)
506 			return (error);
507 
508 		/*
509 		 * If we are operating on a directory file then be sure to
510 		 * do i/o with the vnode for the filesystem instead of the
511 		 * vnode for the directory.
512 		 */
513 		error = bread(pmp->pm_devvp, de_bn2kb(pmp, lbn), blsize,
514 		    NOCRED, 0, &bp);
515 		n = MIN(n, pmp->pm_bpcluster - bp->b_resid);
516 		if (error) {
517 			brelse(bp, 0);
518 			return (error);
519 		}
520 		error = uiomove((char *)bp->b_data + on, (int) n, uio);
521 		brelse(bp, 0);
522 	} while (error == 0 && uio->uio_resid > 0 && n != 0);
523 
524 out:
525 	if ((ap->a_ioflag & IO_SYNC) == IO_SYNC)
526 		error = deupdat(dep, 1);
527 	return (error);
528 }
529 
530 /*
531  * Write data to a file or directory.
532  */
533 int
534 msdosfs_write(void *v)
535 {
536 	struct vop_write_args /* {
537 		struct vnode *a_vp;
538 		struct uio *a_uio;
539 		int a_ioflag;
540 		kauth_cred_t a_cred;
541 	} */ *ap = v;
542 	int resid, extended = 0;
543 	int error = 0;
544 	int ioflag = ap->a_ioflag;
545 	u_long osize;
546 	u_long count;
547 	vsize_t bytelen;
548 	off_t oldoff;
549 	struct uio *uio = ap->a_uio;
550 	struct proc *p = curproc;
551 	struct vnode *vp = ap->a_vp;
552 	struct denode *dep = VTODE(vp);
553 	struct msdosfsmount *pmp = dep->de_pmp;
554 	kauth_cred_t cred = ap->a_cred;
555 	bool async;
556 
557 #ifdef MSDOSFS_DEBUG
558 	printf("msdosfs_write(vp %p, uio %p, ioflag %x, cred %p\n",
559 	    vp, uio, ioflag, cred);
560 	printf("msdosfs_write(): diroff %lu, dirclust %lu, startcluster %lu\n",
561 	    dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster);
562 #endif
563 
564 	switch (vp->v_type) {
565 	case VREG:
566 		if (ioflag & IO_APPEND)
567 			uio->uio_offset = dep->de_FileSize;
568 		break;
569 	case VDIR:
570 		return EISDIR;
571 	default:
572 		panic("msdosfs_write(): bad file type");
573 	}
574 
575 	if (uio->uio_offset < 0)
576 		return (EINVAL);
577 
578 	if (uio->uio_resid == 0)
579 		return (0);
580 
581 	/* Don't bother to try to write files larger than the fs limit */
582 	if (uio->uio_offset + uio->uio_resid > MSDOSFS_FILESIZE_MAX)
583 		return (EFBIG);
584 
585 	/*
586 	 * If they've exceeded their filesize limit, tell them about it.
587 	 */
588 	if (((uio->uio_offset + uio->uio_resid) >
589 	    p->p_rlimit[RLIMIT_FSIZE].rlim_cur)) {
590 		mutex_enter(proc_lock);
591 		psignal(p, SIGXFSZ);
592 		mutex_exit(proc_lock);
593 		return (EFBIG);
594 	}
595 
596 	/*
597 	 * If the offset we are starting the write at is beyond the end of
598 	 * the file, then they've done a seek.  Unix filesystems allow
599 	 * files with holes in them, DOS doesn't so we must fill the hole
600 	 * with zeroed blocks.
601 	 */
602 	if (uio->uio_offset > dep->de_FileSize) {
603 		if ((error = deextend(dep, uio->uio_offset, cred)) != 0)
604 			return (error);
605 	}
606 
607 	/*
608 	 * Remember some values in case the write fails.
609 	 */
610 	async = vp->v_mount->mnt_flag & MNT_ASYNC;
611 	resid = uio->uio_resid;
612 	osize = dep->de_FileSize;
613 
614 	/*
615 	 * If we write beyond the end of the file, extend it to its ultimate
616 	 * size ahead of the time to hopefully get a contiguous area.
617 	 */
618 	if (uio->uio_offset + resid > osize) {
619 		count = de_clcount(pmp, uio->uio_offset + resid) -
620 			de_clcount(pmp, osize);
621 		if ((error = extendfile(dep, count, NULL, NULL, 0)))
622 			goto errexit;
623 
624 		dep->de_FileSize = uio->uio_offset + resid;
625 		/* hint uvm to not read in extended part */
626 		uvm_vnp_setwritesize(vp, dep->de_FileSize);
627 		extended = 1;
628 	}
629 
630 	do {
631 		oldoff = uio->uio_offset;
632 		bytelen = uio->uio_resid;
633 
634 		error = ubc_uiomove(&vp->v_uobj, uio, bytelen,
635 		    IO_ADV_DECODE(ioflag), UBC_WRITE | UBC_UNMAP_FLAG(vp));
636 		if (error)
637 			break;
638 
639 		/*
640 		 * flush what we just wrote if necessary.
641 		 * XXXUBC simplistic async flushing.
642 		 */
643 
644 		if (!async && oldoff >> 16 != uio->uio_offset >> 16) {
645 			mutex_enter(&vp->v_interlock);
646 			error = VOP_PUTPAGES(vp, (oldoff >> 16) << 16,
647 			    (uio->uio_offset >> 16) << 16, PGO_CLEANIT);
648 		}
649 	} while (error == 0 && uio->uio_resid > 0);
650 
651 	/* set final size */
652 	uvm_vnp_setsize(vp, dep->de_FileSize);
653 	if (error == 0 && ioflag & IO_SYNC) {
654 		mutex_enter(&vp->v_interlock);
655 		error = VOP_PUTPAGES(vp, trunc_page(oldoff),
656 		    round_page(oldoff + bytelen), PGO_CLEANIT | PGO_SYNCIO);
657 	}
658 	dep->de_flag |= DE_UPDATE;
659 
660 	/*
661 	 * If the write failed and they want us to, truncate the file back
662 	 * to the size it was before the write was attempted.
663 	 */
664 errexit:
665 	if (resid > uio->uio_resid)
666 		VN_KNOTE(vp, NOTE_WRITE | (extended ? NOTE_EXTEND : 0));
667 	if (error) {
668 		detrunc(dep, osize, ioflag & IO_SYNC, NOCRED);
669 		uio->uio_offset -= resid - uio->uio_resid;
670 		uio->uio_resid = resid;
671 	} else if ((ioflag & IO_SYNC) == IO_SYNC)
672 		error = deupdat(dep, 1);
673 	KASSERT(vp->v_size == dep->de_FileSize);
674 	return (error);
675 }
676 
677 int
678 msdosfs_update(struct vnode *vp, const struct timespec *acc,
679     const struct timespec *mod, int flags)
680 {
681 	struct buf *bp;
682 	struct direntry *dirp;
683 	struct denode *dep;
684 	int error;
685 
686 	if (vp->v_mount->mnt_flag & MNT_RDONLY)
687 		return (0);
688 	dep = VTODE(vp);
689 	DETIMES(dep, acc, mod, NULL, dep->de_pmp->pm_gmtoff);
690 	if ((dep->de_flag & DE_MODIFIED) == 0)
691 		return (0);
692 	dep->de_flag &= ~DE_MODIFIED;
693 	if (dep->de_Attributes & ATTR_DIRECTORY)
694 		return (0);
695 	if (dep->de_refcnt <= 0)
696 		return (0);
697 	error = readde(dep, &bp, &dirp);
698 	if (error)
699 		return (error);
700 	DE_EXTERNALIZE(dirp, dep);
701 	if (flags & (UPDATE_WAIT|UPDATE_DIROP))
702 		return (bwrite(bp));
703 	else {
704 		bdwrite(bp);
705 		return (0);
706 	}
707 }
708 
709 /*
710  * Flush the blocks of a file to disk.
711  *
712  * This function is worthless for vnodes that represent directories. Maybe we
713  * could just do a sync if they try an fsync on a directory file.
714  */
715 int
716 msdosfs_remove(void *v)
717 {
718 	struct vop_remove_args /* {
719 		struct vnode *a_dvp;
720 		struct vnode *a_vp;
721 		struct componentname *a_cnp;
722 	} */ *ap = v;
723 	struct denode *dep = VTODE(ap->a_vp);
724 	struct denode *ddep = VTODE(ap->a_dvp);
725 	int error;
726 
727 	if (ap->a_vp->v_type == VDIR)
728 		error = EPERM;
729 	else
730 		error = removede(ddep, dep);
731 #ifdef MSDOSFS_DEBUG
732 	printf("msdosfs_remove(), dep %p, v_usecount %d\n",
733 		dep, ap->a_vp->v_usecount);
734 #endif
735 	VN_KNOTE(ap->a_vp, NOTE_DELETE);
736 	VN_KNOTE(ap->a_dvp, NOTE_WRITE);
737 	if (ddep == dep)
738 		vrele(ap->a_vp);
739 	else
740 		vput(ap->a_vp);	/* causes msdosfs_inactive() to be called
741 				 * via vrele() */
742 	vput(ap->a_dvp);
743 	return (error);
744 }
745 
746 /*
747  * DOS filesystems don't know what links are. But since we already called
748  * msdosfs_lookup() with create and lockparent, the parent is locked so we
749  * have to free it before we return the error.
750  */
751 int
752 msdosfs_link(void *v)
753 {
754 	struct vop_link_args /* {
755 		struct vnode *a_dvp;
756 		struct vnode *a_vp;
757 		struct componentname *a_cnp;
758 	} */ *ap = v;
759 
760 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
761 	vput(ap->a_dvp);
762 	return (EOPNOTSUPP);
763 }
764 
765 /*
766  * Renames on files require moving the denode to a new hash queue since the
767  * denode's location is used to compute which hash queue to put the file
768  * in. Unless it is a rename in place.  For example "mv a b".
769  *
770  * What follows is the basic algorithm:
771  *
772  * if (file move) {
773  *	if (dest file exists) {
774  *		remove dest file
775  *	}
776  *	if (dest and src in same directory) {
777  *		rewrite name in existing directory slot
778  *	} else {
779  *		write new entry in dest directory
780  *		update offset and dirclust in denode
781  *		move denode to new hash chain
782  *		clear old directory entry
783  *	}
784  * } else {
785  *	directory move
786  *	if (dest directory exists) {
787  *		if (dest is not empty) {
788  *			return ENOTEMPTY
789  *		}
790  *		remove dest directory
791  *	}
792  *	if (dest and src in same directory) {
793  *		rewrite name in existing entry
794  *	} else {
795  *		be sure dest is not a child of src directory
796  *		write entry in dest directory
797  *		update "." and ".." in moved directory
798  *		update offset and dirclust in denode
799  *		move denode to new hash chain
800  *		clear old directory entry for moved directory
801  *	}
802  * }
803  *
804  * On entry:
805  *	source's parent directory is unlocked
806  *	source file or directory is unlocked
807  *	destination's parent directory is locked
808  *	destination file or directory is locked if it exists
809  *
810  * On exit:
811  *	all denodes should be released
812  *
813  * Notes:
814  * I'm not sure how the memory containing the pathnames pointed at by the
815  * componentname structures is freed, there may be some memory bleeding
816  * for each rename done.
817  *
818  * --More-- Notes:
819  * This routine needs help.  badly.
820  */
821 int
822 msdosfs_rename(void *v)
823 {
824 	struct vop_rename_args /* {
825 		struct vnode *a_fdvp;
826 		struct vnode *a_fvp;
827 		struct componentname *a_fcnp;
828 		struct vnode *a_tdvp;
829 		struct vnode *a_tvp;
830 		struct componentname *a_tcnp;
831 	} */ *ap = v;
832 	struct vnode *tvp = ap->a_tvp;
833 	struct vnode *tdvp = ap->a_tdvp;
834 	struct vnode *fvp = ap->a_fvp;
835 	struct vnode *fdvp = ap->a_fdvp;
836 	struct componentname *tcnp = ap->a_tcnp;
837 	struct componentname *fcnp = ap->a_fcnp;
838 	struct denode *ip, *xp, *dp, *zp;
839 	u_char toname[11], oldname[11];
840 	u_long from_diroffset, to_diroffset;
841 	u_char to_count;
842 	int doingdirectory = 0, newparent = 0;
843 	int error;
844 	u_long cn;
845 	daddr_t bn;
846 	struct msdosfsmount *pmp;
847 	struct direntry *dotdotp;
848 	struct buf *bp;
849 	int fdvp_dorele = 0;
850 
851 	pmp = VFSTOMSDOSFS(fdvp->v_mount);
852 
853 #ifdef DIAGNOSTIC
854 	if ((tcnp->cn_flags & HASBUF) == 0 ||
855 	    (fcnp->cn_flags & HASBUF) == 0)
856 		panic("msdosfs_rename: no name");
857 #endif
858 	/*
859 	 * Check for cross-device rename.
860 	 */
861 	if ((fvp->v_mount != tdvp->v_mount) ||
862 	    (tvp && (fvp->v_mount != tvp->v_mount))) {
863 		error = EXDEV;
864 abortit:
865 		VOP_ABORTOP(tdvp, tcnp);
866 		if (tdvp == tvp)
867 			vrele(tdvp);
868 		else
869 			vput(tdvp);
870 		if (tvp)
871 			vput(tvp);
872 		VOP_ABORTOP(fdvp, fcnp);
873 		vrele(fdvp);
874 		vrele(fvp);
875 		return (error);
876 	}
877 
878 	/*
879 	 * If source and dest are the same, do nothing.
880 	 */
881 	if (tvp == fvp) {
882 		error = 0;
883 		goto abortit;
884 	}
885 
886 	/*
887 	 * XXX: This can deadlock since we hold tdvp/tvp locked.
888 	 * But I'm not going to fix it now.
889 	 */
890 	if ((error = vn_lock(fvp, LK_EXCLUSIVE)) != 0)
891 		goto abortit;
892 	dp = VTODE(fdvp);
893 	ip = VTODE(fvp);
894 
895 	/*
896 	 * Be sure we are not renaming ".", "..", or an alias of ".". This
897 	 * leads to a crippled directory tree.  It's pretty tough to do a
898 	 * "ls" or "pwd" with the "." directory entry missing, and "cd .."
899 	 * doesn't work if the ".." entry is missing.
900 	 */
901 	if (ip->de_Attributes & ATTR_DIRECTORY) {
902 		/*
903 		 * Avoid ".", "..", and aliases of "." for obvious reasons.
904 		 */
905 		if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
906 		    dp == ip ||
907 		    (fcnp->cn_flags & ISDOTDOT) ||
908 		    (tcnp->cn_flags & ISDOTDOT) ||
909 		    (ip->de_flag & DE_RENAME)) {
910 			VOP_UNLOCK(fvp, 0);
911 			error = EINVAL;
912 			goto abortit;
913 		}
914 		ip->de_flag |= DE_RENAME;
915 		doingdirectory++;
916 	}
917 	VN_KNOTE(fdvp, NOTE_WRITE);		/* XXXLUKEM/XXX: right place? */
918 
919 	/*
920 	 * When the target exists, both the directory
921 	 * and target vnodes are returned locked.
922 	 */
923 	dp = VTODE(tdvp);
924 	xp = tvp ? VTODE(tvp) : NULL;
925 	/*
926 	 * Remember direntry place to use for destination
927 	 */
928 	to_diroffset = dp->de_fndoffset;
929 	to_count = dp->de_fndcnt;
930 
931 	/*
932 	 * If ".." must be changed (ie the directory gets a new
933 	 * parent) then the source directory must not be in the
934 	 * directory hierarchy above the target, as this would
935 	 * orphan everything below the source directory. Also
936 	 * the user must have write permission in the source so
937 	 * as to be able to change "..". We must repeat the call
938 	 * to namei, as the parent directory is unlocked by the
939 	 * call to doscheckpath().
940 	 */
941 	error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred);
942 	VOP_UNLOCK(fvp, 0);
943 	if (VTODE(fdvp)->de_StartCluster != VTODE(tdvp)->de_StartCluster)
944 		newparent = 1;
945 
946 	/*
947 	 * XXX: We can do this here because rename uses SAVEFART and
948 	 * therefore fdvp has at least two references (one doesn't
949 	 * belong to us, though, and that's evil).  We'll get
950 	 * another "extra" reference when we do relookup(), so we
951 	 * need to compensate.  We should *NOT* be doing this, but
952 	 * it works, so whatever.
953 	 */
954 	vrele(fdvp);
955 
956 	if (doingdirectory && newparent) {
957 		if (error)	/* write access check above */
958 			goto tdvpbad;
959 		if (xp != NULL)
960 			vput(tvp);
961 		tvp = NULL;
962 		/*
963 		 * doscheckpath() vput()'s dp,
964 		 * so we have to do a relookup afterwards
965 		 */
966 		if ((error = doscheckpath(ip, dp)) != 0)
967 			goto out;
968 		if ((tcnp->cn_flags & SAVESTART) == 0)
969 			panic("msdosfs_rename: lost to startdir");
970 		vn_lock(tdvp, LK_EXCLUSIVE | LK_RETRY);
971 		if ((error = relookup(tdvp, &tvp, tcnp)) != 0) {
972 			VOP_UNLOCK(tdvp, 0);
973 			goto out;
974 		}
975 		/*
976 		 * XXX: SAVESTART causes us to get a reference, but
977 		 * that's released already above in doscheckpath()
978 		 */
979 		dp = VTODE(tdvp);
980 		xp = tvp ? VTODE(tvp) : NULL;
981 	}
982 
983 	if (xp != NULL) {
984 		/*
985 		 * Target must be empty if a directory and have no links
986 		 * to it. Also, ensure source and target are compatible
987 		 * (both directories, or both not directories).
988 		 */
989 		if (xp->de_Attributes & ATTR_DIRECTORY) {
990 			if (!dosdirempty(xp)) {
991 				error = ENOTEMPTY;
992 				goto tdvpbad;
993 			}
994 			if (!doingdirectory) {
995 				error = ENOTDIR;
996 				goto tdvpbad;
997 			}
998 		} else if (doingdirectory) {
999 			error = EISDIR;
1000 			goto tdvpbad;
1001 		}
1002 		if ((error = removede(dp, xp)) != 0)
1003 			goto tdvpbad;
1004 		VN_KNOTE(tdvp, NOTE_WRITE);
1005 		VN_KNOTE(tvp, NOTE_DELETE);
1006 		cache_purge(tvp);
1007 		vput(tvp);
1008 		tvp = NULL;
1009 		xp = NULL;
1010 	}
1011 
1012 	/*
1013 	 * Convert the filename in tcnp into a dos filename. We copy this
1014 	 * into the denode and directory entry for the destination
1015 	 * file/directory.
1016 	 */
1017 	if ((error = uniqdosname(VTODE(tdvp), tcnp, toname)) != 0)
1018 		goto abortit;
1019 
1020 	/*
1021 	 * Since from wasn't locked at various places above,
1022 	 * have to do a relookup here.
1023 	 */
1024 	fcnp->cn_flags &= ~MODMASK;
1025 	fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
1026 	if ((fcnp->cn_flags & SAVESTART) == 0)
1027 		panic("msdosfs_rename: lost from startdir");
1028 	VOP_UNLOCK(tdvp, 0);
1029 	vn_lock(fdvp, LK_EXCLUSIVE | LK_RETRY);
1030 	if ((error = relookup(fdvp, &fvp, fcnp))) {
1031 		VOP_UNLOCK(fdvp, 0);
1032 		vrele(ap->a_fvp);
1033 		vrele(tdvp);
1034 		return (error);
1035 	}
1036 	if (fvp == NULL) {
1037 		/*
1038 		 * From name has disappeared.
1039 		 */
1040 		if (doingdirectory)
1041 			panic("rename: lost dir entry");
1042 		vput(fdvp);
1043 		vrele(ap->a_fvp);
1044 		vrele(tdvp);
1045 		return 0;
1046 	}
1047 	fdvp_dorele = 1;
1048 	VOP_UNLOCK(fdvp, 0);
1049 	xp = VTODE(fvp);
1050 	zp = VTODE(fdvp);
1051 	from_diroffset = zp->de_fndoffset;
1052 
1053 	/*
1054 	 * Ensure that the directory entry still exists and has not
1055 	 * changed till now. If the source is a file the entry may
1056 	 * have been unlinked or renamed. In either case there is
1057 	 * no further work to be done. If the source is a directory
1058 	 * then it cannot have been rmdir'ed or renamed; this is
1059 	 * prohibited by the DE_RENAME flag.
1060 	 */
1061 	if (xp != ip) {
1062 		if (doingdirectory)
1063 			panic("rename: lost dir entry");
1064 		vrele(ap->a_fvp);
1065 		VOP_UNLOCK(fvp, 0);
1066 		xp = NULL;
1067 	} else {
1068 		vrele(fvp);
1069 		xp = NULL;
1070 
1071 		/*
1072 		 * First write a new entry in the destination
1073 		 * directory and mark the entry in the source directory
1074 		 * as deleted.  Then move the denode to the correct hash
1075 		 * chain for its new location in the filesystem.  And, if
1076 		 * we moved a directory, then update its .. entry to point
1077 		 * to the new parent directory.
1078 		 */
1079 		memcpy(oldname, ip->de_Name, 11);
1080 		memcpy(ip->de_Name, toname, 11);	/* update denode */
1081 		dp->de_fndoffset = to_diroffset;
1082 		dp->de_fndcnt = to_count;
1083 		error = createde(ip, dp, (struct denode **)0, tcnp);
1084 		if (error) {
1085 			memcpy(ip->de_Name, oldname, 11);
1086 			VOP_UNLOCK(fvp, 0);
1087 			goto bad;
1088 		}
1089 		ip->de_refcnt++;
1090 		zp->de_fndoffset = from_diroffset;
1091 		if ((error = removede(zp, ip)) != 0) {
1092 			/* XXX should really panic here, fs is corrupt */
1093 			VOP_UNLOCK(fvp, 0);
1094 			goto bad;
1095 		}
1096 		cache_purge(fvp);
1097 		if (!doingdirectory) {
1098 			error = pcbmap(dp, de_cluster(pmp, to_diroffset), 0,
1099 				       &ip->de_dirclust, 0);
1100 			if (error) {
1101 				/* XXX should really panic here, fs is corrupt */
1102 				VOP_UNLOCK(fvp, 0);
1103 				goto bad;
1104 			}
1105 			ip->de_diroffset = to_diroffset;
1106 			if (ip->de_dirclust != MSDOSFSROOT)
1107 				ip->de_diroffset &= pmp->pm_crbomask;
1108 		}
1109 		reinsert(ip);
1110 	}
1111 
1112 	/*
1113 	 * If we moved a directory to a new parent directory, then we must
1114 	 * fixup the ".." entry in the moved directory.
1115 	 */
1116 	if (doingdirectory && newparent) {
1117 		cn = ip->de_StartCluster;
1118 		if (cn == MSDOSFSROOT) {
1119 			/* this should never happen */
1120 			panic("msdosfs_rename: updating .. in root directory?");
1121 		} else
1122 			bn = cntobn(pmp, cn);
1123 		error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn),
1124 		    pmp->pm_bpcluster, NOCRED, B_MODIFY, &bp);
1125 		if (error) {
1126 			/* XXX should really panic here, fs is corrupt */
1127 			brelse(bp, 0);
1128 			VOP_UNLOCK(fvp, 0);
1129 			goto bad;
1130 		}
1131 		dotdotp = (struct direntry *)bp->b_data + 1;
1132 		putushort(dotdotp->deStartCluster, dp->de_StartCluster);
1133 		if (FAT32(pmp)) {
1134 			putushort(dotdotp->deHighClust,
1135 				dp->de_StartCluster >> 16);
1136 		} else {
1137 			putushort(dotdotp->deHighClust, 0);
1138 		}
1139 		if ((error = bwrite(bp)) != 0) {
1140 			/* XXX should really panic here, fs is corrupt */
1141 			VOP_UNLOCK(fvp, 0);
1142 			goto bad;
1143 		}
1144 	}
1145 
1146 	VN_KNOTE(fvp, NOTE_RENAME);
1147 	VOP_UNLOCK(fvp, 0);
1148 bad:
1149 	if (tvp)
1150 		vput(tvp);
1151 	vrele(tdvp);
1152 out:
1153 	ip->de_flag &= ~DE_RENAME;
1154 	if (fdvp_dorele)
1155 		vrele(fdvp);
1156 	vrele(fvp);
1157 	return (error);
1158 
1159 	/* XXX: uuuh */
1160 tdvpbad:
1161 	VOP_UNLOCK(tdvp, 0);
1162 	goto bad;
1163 }
1164 
1165 static const struct {
1166 	struct direntry dot;
1167 	struct direntry dotdot;
1168 } dosdirtemplate = {
1169 	{	".       ", "   ",			/* the . entry */
1170 		ATTR_DIRECTORY,				/* file attribute */
1171 		0,	 				/* reserved */
1172 		0, { 0, 0 }, { 0, 0 },			/* create time & date */
1173 		{ 0, 0 },				/* access date */
1174 		{ 0, 0 },				/* high bits of start cluster */
1175 		{ 210, 4 }, { 210, 4 },			/* modify time & date */
1176 		{ 0, 0 },				/* startcluster */
1177 		{ 0, 0, 0, 0 } 				/* filesize */
1178 	},
1179 	{	"..      ", "   ",			/* the .. entry */
1180 		ATTR_DIRECTORY,				/* file attribute */
1181 		0,	 				/* reserved */
1182 		0, { 0, 0 }, { 0, 0 },			/* create time & date */
1183 		{ 0, 0 },				/* access date */
1184 		{ 0, 0 },				/* high bits of start cluster */
1185 		{ 210, 4 }, { 210, 4 },			/* modify time & date */
1186 		{ 0, 0 },				/* startcluster */
1187 		{ 0, 0, 0, 0 }				/* filesize */
1188 	}
1189 };
1190 
1191 int
1192 msdosfs_mkdir(void *v)
1193 {
1194 	struct vop_mkdir_args /* {
1195 		struct vnode *a_dvp;
1196 		struvt vnode **a_vpp;
1197 		struvt componentname *a_cnp;
1198 		struct vattr *a_vap;
1199 	} */ *ap = v;
1200 	struct componentname *cnp = ap->a_cnp;
1201 	struct denode ndirent;
1202 	struct denode *dep;
1203 	struct denode *pdep = VTODE(ap->a_dvp);
1204 	int error;
1205 	int bn;
1206 	u_long newcluster, pcl;
1207 	daddr_t lbn;
1208 	struct direntry *denp;
1209 	struct msdosfsmount *pmp = pdep->de_pmp;
1210 	struct buf *bp;
1211 	int async = pdep->de_pmp->pm_mountp->mnt_flag & MNT_ASYNC;
1212 
1213 	/*
1214 	 * If this is the root directory and there is no space left we
1215 	 * can't do anything.  This is because the root directory can not
1216 	 * change size.
1217 	 */
1218 	if (pdep->de_StartCluster == MSDOSFSROOT
1219 	    && pdep->de_fndoffset >= pdep->de_FileSize) {
1220 		error = ENOSPC;
1221 		goto bad2;
1222 	}
1223 
1224 	/*
1225 	 * Allocate a cluster to hold the about to be created directory.
1226 	 */
1227 	error = clusteralloc(pmp, 0, 1, &newcluster, NULL);
1228 	if (error)
1229 		goto bad2;
1230 
1231 	memset(&ndirent, 0, sizeof(ndirent));
1232 	ndirent.de_pmp = pmp;
1233 	ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
1234 	DETIMES(&ndirent, NULL, NULL, NULL, pmp->pm_gmtoff);
1235 
1236 	/*
1237 	 * Now fill the cluster with the "." and ".." entries. And write
1238 	 * the cluster to disk.  This way it is there for the parent
1239 	 * directory to be pointing at if there were a crash.
1240 	 */
1241 	bn = cntobn(pmp, newcluster);
1242 	lbn = de_bn2kb(pmp, bn);
1243 	/* always succeeds */
1244 	bp = getblk(pmp->pm_devvp, lbn, pmp->pm_bpcluster, 0, 0);
1245 	memset(bp->b_data, 0, pmp->pm_bpcluster);
1246 	memcpy(bp->b_data, &dosdirtemplate, sizeof dosdirtemplate);
1247 	denp = (struct direntry *)bp->b_data;
1248 	putushort(denp[0].deStartCluster, newcluster);
1249 	putushort(denp[0].deCDate, ndirent.de_CDate);
1250 	putushort(denp[0].deCTime, ndirent.de_CTime);
1251 	denp[0].deCHundredth = ndirent.de_CHun;
1252 	putushort(denp[0].deADate, ndirent.de_ADate);
1253 	putushort(denp[0].deMDate, ndirent.de_MDate);
1254 	putushort(denp[0].deMTime, ndirent.de_MTime);
1255 	pcl = pdep->de_StartCluster;
1256 	if (FAT32(pmp) && pcl == pmp->pm_rootdirblk)
1257 		pcl = 0;
1258 	putushort(denp[1].deStartCluster, pcl);
1259 	putushort(denp[1].deCDate, ndirent.de_CDate);
1260 	putushort(denp[1].deCTime, ndirent.de_CTime);
1261 	denp[1].deCHundredth = ndirent.de_CHun;
1262 	putushort(denp[1].deADate, ndirent.de_ADate);
1263 	putushort(denp[1].deMDate, ndirent.de_MDate);
1264 	putushort(denp[1].deMTime, ndirent.de_MTime);
1265 	if (FAT32(pmp)) {
1266 		putushort(denp[0].deHighClust, newcluster >> 16);
1267 		putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16);
1268 	} else {
1269 		putushort(denp[0].deHighClust, 0);
1270 		putushort(denp[1].deHighClust, 0);
1271 	}
1272 
1273 	if (async)
1274 		bdwrite(bp);
1275 	else if ((error = bwrite(bp)) != 0)
1276 		goto bad;
1277 
1278 	/*
1279 	 * Now build up a directory entry pointing to the newly allocated
1280 	 * cluster.  This will be written to an empty slot in the parent
1281 	 * directory.
1282 	 */
1283 #ifdef DIAGNOSTIC
1284 	if ((cnp->cn_flags & HASBUF) == 0)
1285 		panic("msdosfs_mkdir: no name");
1286 #endif
1287 	if ((error = uniqdosname(pdep, cnp, ndirent.de_Name)) != 0)
1288 		goto bad;
1289 
1290 	ndirent.de_Attributes = ATTR_DIRECTORY;
1291 	ndirent.de_StartCluster = newcluster;
1292 	ndirent.de_FileSize = 0;
1293 	ndirent.de_dev = pdep->de_dev;
1294 	ndirent.de_devvp = pdep->de_devvp;
1295 	if ((error = createde(&ndirent, pdep, &dep, cnp)) != 0)
1296 		goto bad;
1297 	if ((cnp->cn_flags & SAVESTART) == 0)
1298 		PNBUF_PUT(cnp->cn_pnbuf);
1299 	VN_KNOTE(ap->a_dvp, NOTE_WRITE | NOTE_LINK);
1300 	vput(ap->a_dvp);
1301 	*ap->a_vpp = DETOV(dep);
1302 	return (0);
1303 
1304 bad:
1305 	clusterfree(pmp, newcluster, NULL);
1306 bad2:
1307 	PNBUF_PUT(cnp->cn_pnbuf);
1308 	vput(ap->a_dvp);
1309 	return (error);
1310 }
1311 
1312 int
1313 msdosfs_rmdir(void *v)
1314 {
1315 	struct vop_rmdir_args /* {
1316 		struct vnode *a_dvp;
1317 		struct vnode *a_vp;
1318 		struct componentname *a_cnp;
1319 	} */ *ap = v;
1320 	struct vnode *vp = ap->a_vp;
1321 	struct vnode *dvp = ap->a_dvp;
1322 	struct componentname *cnp = ap->a_cnp;
1323 	struct denode *ip, *dp;
1324 	int error;
1325 
1326 	ip = VTODE(vp);
1327 	dp = VTODE(dvp);
1328 	/*
1329 	 * No rmdir "." please.
1330 	 */
1331 	if (dp == ip) {
1332 		vrele(dvp);
1333 		vput(vp);
1334 		return (EINVAL);
1335 	}
1336 	/*
1337 	 * Verify the directory is empty (and valid).
1338 	 * (Rmdir ".." won't be valid since
1339 	 *  ".." will contain a reference to
1340 	 *  the current directory and thus be
1341 	 *  non-empty.)
1342 	 */
1343 	error = 0;
1344 	if (!dosdirempty(ip) || ip->de_flag & DE_RENAME) {
1345 		error = ENOTEMPTY;
1346 		goto out;
1347 	}
1348 	/*
1349 	 * Delete the entry from the directory.  For dos filesystems this
1350 	 * gets rid of the directory entry on disk, the in memory copy
1351 	 * still exists but the de_refcnt is <= 0.  This prevents it from
1352 	 * being found by deget().  When the vput() on dep is done we give
1353 	 * up access and eventually msdosfs_reclaim() will be called which
1354 	 * will remove it from the denode cache.
1355 	 */
1356 	if ((error = removede(dp, ip)) != 0)
1357 		goto out;
1358 	/*
1359 	 * This is where we decrement the link count in the parent
1360 	 * directory.  Since dos filesystems don't do this we just purge
1361 	 * the name cache and let go of the parent directory denode.
1362 	 */
1363 	VN_KNOTE(dvp, NOTE_WRITE | NOTE_LINK);
1364 	cache_purge(dvp);
1365 	vput(dvp);
1366 	dvp = NULL;
1367 	/*
1368 	 * Truncate the directory that is being deleted.
1369 	 */
1370 	error = detrunc(ip, (u_long)0, IO_SYNC, cnp->cn_cred);
1371 	cache_purge(vp);
1372 out:
1373 	VN_KNOTE(vp, NOTE_DELETE);
1374 	if (dvp)
1375 		vput(dvp);
1376 	vput(vp);
1377 	return (error);
1378 }
1379 
1380 /*
1381  * DOS filesystems don't know what symlinks are.
1382  */
1383 int
1384 msdosfs_symlink(void *v)
1385 {
1386 	struct vop_symlink_args /* {
1387 		struct vnode *a_dvp;
1388 		struct vnode **a_vpp;
1389 		struct componentname *a_cnp;
1390 		struct vattr *a_vap;
1391 		char *a_target;
1392 	} */ *ap = v;
1393 
1394 	VOP_ABORTOP(ap->a_dvp, ap->a_cnp);
1395 	vput(ap->a_dvp);
1396 	return (EOPNOTSUPP);
1397 }
1398 
1399 int
1400 msdosfs_readdir(void *v)
1401 {
1402 	struct vop_readdir_args /* {
1403 		struct vnode *a_vp;
1404 		struct uio *a_uio;
1405 		kauth_cred_t a_cred;
1406 		int *a_eofflag;
1407 		off_t **a_cookies;
1408 		int *a_ncookies;
1409 	} */ *ap = v;
1410 	int error = 0;
1411 	int diff;
1412 	long n;
1413 	int blsize;
1414 	long on;
1415 	long lost;
1416 	long count;
1417 	u_long cn;
1418 	ino_t fileno;
1419 	u_long dirsperblk;
1420 	long bias = 0;
1421 	daddr_t bn, lbn;
1422 	struct buf *bp;
1423 	struct denode *dep = VTODE(ap->a_vp);
1424 	struct msdosfsmount *pmp = dep->de_pmp;
1425 	struct direntry *dentp;
1426 	struct dirent *dirbuf;
1427 	struct uio *uio = ap->a_uio;
1428 	off_t *cookies = NULL;
1429 	int ncookies = 0, nc = 0;
1430 	off_t offset, uio_off;
1431 	int chksum = -1;
1432 
1433 #ifdef MSDOSFS_DEBUG
1434 	printf("msdosfs_readdir(): vp %p, uio %p, cred %p, eofflagp %p\n",
1435 	    ap->a_vp, uio, ap->a_cred, ap->a_eofflag);
1436 #endif
1437 
1438 	/*
1439 	 * msdosfs_readdir() won't operate properly on regular files since
1440 	 * it does i/o only with the filesystem vnode, and hence can
1441 	 * retrieve the wrong block from the buffer cache for a plain file.
1442 	 * So, fail attempts to readdir() on a plain file.
1443 	 */
1444 	if ((dep->de_Attributes & ATTR_DIRECTORY) == 0)
1445 		return (ENOTDIR);
1446 
1447 	/*
1448 	 * If the user buffer is smaller than the size of one dos directory
1449 	 * entry or the file offset is not a multiple of the size of a
1450 	 * directory entry, then we fail the read.
1451 	 */
1452 	count = uio->uio_resid & ~(sizeof(struct direntry) - 1);
1453 	offset = uio->uio_offset;
1454 	if (count < sizeof(struct direntry) ||
1455 	    (offset & (sizeof(struct direntry) - 1)))
1456 		return (EINVAL);
1457 	lost = uio->uio_resid - count;
1458 	uio->uio_resid = count;
1459 	uio_off = uio->uio_offset;
1460 
1461 	/* Allocate a temporary dirent buffer. */
1462 	dirbuf = malloc(sizeof(struct dirent), M_MSDOSFSTMP, M_WAITOK | M_ZERO);
1463 
1464 	if (ap->a_ncookies) {
1465 		nc = uio->uio_resid / _DIRENT_MINSIZE((struct dirent *)0);
1466 		cookies = malloc(nc * sizeof (off_t), M_TEMP, M_WAITOK);
1467 		*ap->a_cookies = cookies;
1468 	}
1469 
1470 	dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
1471 
1472 	/*
1473 	 * If they are reading from the root directory then, we simulate
1474 	 * the . and .. entries since these don't exist in the root
1475 	 * directory.  We also set the offset bias to make up for having to
1476 	 * simulate these entries. By this I mean that at file offset 64 we
1477 	 * read the first entry in the root directory that lives on disk.
1478 	 */
1479 	if (dep->de_StartCluster == MSDOSFSROOT
1480 	    || (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)) {
1481 #if 0
1482 		printf("msdosfs_readdir(): going after . or .. in root dir, "
1483 		    "offset %" PRIu64 "\n", offset);
1484 #endif
1485 		bias = 2 * sizeof(struct direntry);
1486 		if (offset < bias) {
1487 			for (n = (int)offset / sizeof(struct direntry);
1488 			     n < 2; n++) {
1489 				if (FAT32(pmp))
1490 					dirbuf->d_fileno = cntobn(pmp,
1491 					     (ino_t)pmp->pm_rootdirblk)
1492 					     * dirsperblk;
1493 				else
1494 					dirbuf->d_fileno = 1;
1495 				dirbuf->d_type = DT_DIR;
1496 				switch (n) {
1497 				case 0:
1498 					dirbuf->d_namlen = 1;
1499 					strlcpy(dirbuf->d_name, ".",
1500 					    sizeof(dirbuf->d_name));
1501 					break;
1502 				case 1:
1503 					dirbuf->d_namlen = 2;
1504 					strlcpy(dirbuf->d_name, "..",
1505 					    sizeof(dirbuf->d_name));
1506 					break;
1507 				}
1508 				dirbuf->d_reclen = _DIRENT_SIZE(dirbuf);
1509 				if (uio->uio_resid < dirbuf->d_reclen)
1510 					goto out;
1511 				error = uiomove(dirbuf, dirbuf->d_reclen, uio);
1512 				if (error)
1513 					goto out;
1514 				offset += sizeof(struct direntry);
1515 				uio_off = offset;
1516 				if (cookies) {
1517 					*cookies++ = offset;
1518 					ncookies++;
1519 					if (ncookies >= nc)
1520 						goto out;
1521 				}
1522 			}
1523 		}
1524 	}
1525 
1526 	while (uio->uio_resid > 0) {
1527 		lbn = de_cluster(pmp, offset - bias);
1528 		on = (offset - bias) & pmp->pm_crbomask;
1529 		n = MIN(pmp->pm_bpcluster - on, uio->uio_resid);
1530 		diff = dep->de_FileSize - (offset - bias);
1531 		if (diff <= 0)
1532 			break;
1533 		n = MIN(n, diff);
1534 		if ((error = pcbmap(dep, lbn, &bn, &cn, &blsize)) != 0)
1535 			break;
1536 		error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize,
1537 		    NOCRED, 0, &bp);
1538 		if (error) {
1539 			brelse(bp, 0);
1540 			free(dirbuf, M_MSDOSFSTMP);
1541 			return (error);
1542 		}
1543 		n = MIN(n, blsize - bp->b_resid);
1544 
1545 		/*
1546 		 * Convert from dos directory entries to fs-independent
1547 		 * directory entries.
1548 		 */
1549 		for (dentp = (struct direntry *)((char *)bp->b_data + on);
1550 		     (char *)dentp < (char *)bp->b_data + on + n;
1551 		     dentp++, offset += sizeof(struct direntry)) {
1552 #if 0
1553 
1554 			printf("rd: dentp %08x prev %08x crnt %08x deName %02x attr %02x\n",
1555 			    dentp, prev, crnt, dentp->deName[0], dentp->deAttributes);
1556 #endif
1557 			/*
1558 			 * If this is an unused entry, we can stop.
1559 			 */
1560 			if (dentp->deName[0] == SLOT_EMPTY) {
1561 				brelse(bp, 0);
1562 				goto out;
1563 			}
1564 			/*
1565 			 * Skip deleted entries.
1566 			 */
1567 			if (dentp->deName[0] == SLOT_DELETED) {
1568 				chksum = -1;
1569 				continue;
1570 			}
1571 
1572 			/*
1573 			 * Handle Win95 long directory entries
1574 			 */
1575 			if (dentp->deAttributes == ATTR_WIN95) {
1576 				if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
1577 					continue;
1578 				chksum = win2unixfn((struct winentry *)dentp,
1579 				    dirbuf, chksum);
1580 				continue;
1581 			}
1582 
1583 			/*
1584 			 * Skip volume labels
1585 			 */
1586 			if (dentp->deAttributes & ATTR_VOLUME) {
1587 				chksum = -1;
1588 				continue;
1589 			}
1590 			/*
1591 			 * This computation of d_fileno must match
1592 			 * the computation of va_fileid in
1593 			 * msdosfs_getattr.
1594 			 */
1595 			if (dentp->deAttributes & ATTR_DIRECTORY) {
1596 				fileno = getushort(dentp->deStartCluster);
1597 				if (FAT32(pmp))
1598 					fileno |= ((ino_t)getushort(dentp->deHighClust)) << 16;
1599 				/* if this is the root directory */
1600 				if (fileno == MSDOSFSROOT)
1601 					if (FAT32(pmp))
1602 						fileno = cntobn(pmp,
1603 						    (ino_t)pmp->pm_rootdirblk)
1604 						    * dirsperblk;
1605 					else
1606 						fileno = 1;
1607 				else
1608 					fileno = cntobn(pmp, fileno) * dirsperblk;
1609 				dirbuf->d_fileno = fileno;
1610 				dirbuf->d_type = DT_DIR;
1611 			} else {
1612 				dirbuf->d_fileno =
1613 				    offset / sizeof(struct direntry);
1614 				dirbuf->d_type = DT_REG;
1615 			}
1616 			if (chksum != winChksum(dentp->deName))
1617 				dirbuf->d_namlen = dos2unixfn(dentp->deName,
1618 				    (u_char *)dirbuf->d_name,
1619 				    pmp->pm_flags & MSDOSFSMNT_SHORTNAME);
1620 			else
1621 				dirbuf->d_name[dirbuf->d_namlen] = 0;
1622 			chksum = -1;
1623 			dirbuf->d_reclen = _DIRENT_SIZE(dirbuf);
1624 			if (uio->uio_resid < dirbuf->d_reclen) {
1625 				brelse(bp, 0);
1626 				goto out;
1627 			}
1628 			error = uiomove(dirbuf, dirbuf->d_reclen, uio);
1629 			if (error) {
1630 				brelse(bp, 0);
1631 				goto out;
1632 			}
1633 			uio_off = offset + sizeof(struct direntry);
1634 			if (cookies) {
1635 				*cookies++ = offset + sizeof(struct direntry);
1636 				ncookies++;
1637 				if (ncookies >= nc) {
1638 					brelse(bp, 0);
1639 					goto out;
1640 				}
1641 			}
1642 		}
1643 		brelse(bp, 0);
1644 	}
1645 
1646 out:
1647 	uio->uio_offset = uio_off;
1648 	uio->uio_resid += lost;
1649 	if (dep->de_FileSize - (offset - bias) <= 0)
1650 		*ap->a_eofflag = 1;
1651 	else
1652 		*ap->a_eofflag = 0;
1653 
1654 	if (ap->a_ncookies) {
1655 		if (error) {
1656 			free(*ap->a_cookies, M_TEMP);
1657 			*ap->a_ncookies = 0;
1658 			*ap->a_cookies = NULL;
1659 		} else
1660 			*ap->a_ncookies = ncookies;
1661 	}
1662 	free(dirbuf, M_MSDOSFSTMP);
1663 	return (error);
1664 }
1665 
1666 /*
1667  * DOS filesystems don't know what symlinks are.
1668  */
1669 int
1670 msdosfs_readlink(void *v)
1671 {
1672 #if 0
1673 	struct vop_readlink_args /* {
1674 		struct vnode *a_vp;
1675 		struct uio *a_uio;
1676 		kauth_cred_t a_cred;
1677 	} */ *ap;
1678 #endif
1679 
1680 	return (EINVAL);
1681 }
1682 
1683 /*
1684  * vp  - address of vnode file the file
1685  * bn  - which cluster we are interested in mapping to a filesystem block number.
1686  * vpp - returns the vnode for the block special file holding the filesystem
1687  *	 containing the file of interest
1688  * bnp - address of where to return the filesystem relative block number
1689  */
1690 int
1691 msdosfs_bmap(void *v)
1692 {
1693 	struct vop_bmap_args /* {
1694 		struct vnode *a_vp;
1695 		daddr_t a_bn;
1696 		struct vnode **a_vpp;
1697 		daddr_t *a_bnp;
1698 		int *a_runp;
1699 	} */ *ap = v;
1700 	struct denode *dep = VTODE(ap->a_vp);
1701 	int run, maxrun;
1702 	daddr_t runbn;
1703 	int status;
1704 
1705 	if (ap->a_vpp != NULL)
1706 		*ap->a_vpp = dep->de_devvp;
1707 	if (ap->a_bnp == NULL)
1708 		return (0);
1709 	status = pcbmap(dep, ap->a_bn, ap->a_bnp, 0, 0);
1710 
1711 	/*
1712 	 * From FreeBSD:
1713 	 * A little kludgy, but we loop calling pcbmap until we
1714 	 * reach the end of the contiguous piece, or reach MAXPHYS.
1715 	 * Since it reduces disk I/Os, the "wasted" CPU is put to
1716 	 * good use (4 to 5 fold sequential read I/O improvement on USB
1717 	 * drives).
1718 	 */
1719 	if (ap->a_runp != NULL) {
1720 		/* taken from ufs_bmap */
1721 		maxrun = ulmin(MAXPHYS / dep->de_pmp->pm_bpcluster - 1,
1722 			       dep->de_pmp->pm_maxcluster - ap->a_bn);
1723 		for (run = 1; run <= maxrun; run++) {
1724 			if (pcbmap(dep, ap->a_bn + run, &runbn, NULL, NULL)
1725 			    != 0 || runbn !=
1726 			            *ap->a_bnp + de_cn2bn(dep->de_pmp, run))
1727 				break;
1728 		}
1729 		*ap->a_runp = run - 1;
1730 	}
1731 
1732 	/*
1733 	 * We need to scale *ap->a_bnp by sector_size/DEV_BSIZE
1734 	 */
1735 	*ap->a_bnp = de_bn2kb(dep->de_pmp, *ap->a_bnp);
1736 	return status;
1737 }
1738 
1739 int
1740 msdosfs_strategy(void *v)
1741 {
1742 	struct vop_strategy_args /* {
1743 		struct vnode *a_vp;
1744 		struct buf *a_bp;
1745 	} */ *ap = v;
1746 	struct vnode *vp = ap->a_vp;
1747 	struct buf *bp = ap->a_bp;
1748 	struct denode *dep = VTODE(bp->b_vp);
1749 	int error = 0;
1750 
1751 	if (vp->v_type == VBLK || vp->v_type == VCHR)
1752 		panic("msdosfs_strategy: spec");
1753 	/*
1754 	 * If we don't already know the filesystem relative block number
1755 	 * then get it using pcbmap().  If pcbmap() returns the block
1756 	 * number as -1 then we've got a hole in the file.  DOS filesystems
1757 	 * don't allow files with holes, so we shouldn't ever see this.
1758 	 */
1759 	if (bp->b_blkno == bp->b_lblkno) {
1760 		error = pcbmap(dep, de_bn2cn(dep->de_pmp, bp->b_lblkno),
1761 			       &bp->b_blkno, 0, 0);
1762 		if (error)
1763 			bp->b_blkno = -1;
1764 		if (bp->b_blkno == -1)
1765 			clrbuf(bp);
1766 		else
1767 			bp->b_blkno = de_bn2kb(dep->de_pmp, bp->b_blkno);
1768 	}
1769 	if (bp->b_blkno == -1) {
1770 		biodone(bp);
1771 		return (error);
1772 	}
1773 
1774 	/*
1775 	 * Read/write the block from/to the disk that contains the desired
1776 	 * file block.
1777 	 */
1778 
1779 	vp = dep->de_devvp;
1780 	return (VOP_STRATEGY(vp, bp));
1781 }
1782 
1783 int
1784 msdosfs_print(void *v)
1785 {
1786 	struct vop_print_args /* {
1787 		struct vnode *vp;
1788 	} */ *ap = v;
1789 	struct denode *dep = VTODE(ap->a_vp);
1790 
1791 	printf(
1792 	    "tag VT_MSDOSFS, startcluster %ld, dircluster %ld, diroffset %ld ",
1793 	    dep->de_StartCluster, dep->de_dirclust, dep->de_diroffset);
1794 	printf(" dev %llu, %llu ", (unsigned long long)major(dep->de_dev),
1795 	    (unsigned long long)minor(dep->de_dev));
1796 	printf("\n");
1797 	return (0);
1798 }
1799 
1800 int
1801 msdosfs_advlock(void *v)
1802 {
1803 	struct vop_advlock_args /* {
1804 		struct vnode *a_vp;
1805 		void *a_id;
1806 		int a_op;
1807 		struct flock *a_fl;
1808 		int a_flags;
1809 	} */ *ap = v;
1810 	struct denode *dep = VTODE(ap->a_vp);
1811 
1812 	return lf_advlock(ap, &dep->de_lockf, dep->de_FileSize);
1813 }
1814 
1815 int
1816 msdosfs_pathconf(void *v)
1817 {
1818 	struct vop_pathconf_args /* {
1819 		struct vnode *a_vp;
1820 		int a_name;
1821 		register_t *a_retval;
1822 	} */ *ap = v;
1823 
1824 	switch (ap->a_name) {
1825 	case _PC_LINK_MAX:
1826 		*ap->a_retval = 1;
1827 		return (0);
1828 	case _PC_NAME_MAX:
1829 		*ap->a_retval = ap->a_vp->v_mount->mnt_stat.f_namemax;
1830 		return (0);
1831 	case _PC_PATH_MAX:
1832 		*ap->a_retval = PATH_MAX;
1833 		return (0);
1834 	case _PC_CHOWN_RESTRICTED:
1835 		*ap->a_retval = 1;
1836 		return (0);
1837 	case _PC_NO_TRUNC:
1838 		*ap->a_retval = 0;
1839 		return (0);
1840 	case _PC_SYNC_IO:
1841 		*ap->a_retval = 1;
1842 		return (0);
1843 	case _PC_FILESIZEBITS:
1844 		*ap->a_retval = 32;
1845 		return (0);
1846 	default:
1847 		return (EINVAL);
1848 	}
1849 	/* NOTREACHED */
1850 }
1851 
1852 int
1853 msdosfs_fsync(void *v)
1854 {
1855 	struct vop_fsync_args /* {
1856 		struct vnode *a_vp;
1857 		kauth_cred_t a_cred;
1858 		int a_flags;
1859 		off_t offlo;
1860 		off_t offhi;
1861 	} */ *ap = v;
1862 	struct vnode *vp = ap->a_vp;
1863 	int wait;
1864 	int error;
1865 
1866 	wait = (ap->a_flags & FSYNC_WAIT) != 0;
1867 	vflushbuf(vp, wait);
1868 	if ((ap->a_flags & FSYNC_DATAONLY) != 0)
1869 		error = 0;
1870 	else
1871 		error = msdosfs_update(vp, NULL, NULL, wait ? UPDATE_WAIT : 0);
1872 
1873 	if (error == 0 && ap->a_flags & FSYNC_CACHE) {
1874 		struct denode *dep = VTODE(vp);
1875 		struct vnode *devvp = dep->de_devvp;
1876 
1877 		int l = 0;
1878 		error = VOP_IOCTL(devvp, DIOCCACHESYNC, &l, FWRITE,
1879 					  curlwp->l_cred);
1880 	}
1881 
1882 	return (error);
1883 }
1884 
1885 void
1886 msdosfs_detimes(struct denode *dep, const struct timespec *acc,
1887     const struct timespec *mod, const struct timespec *cre, int gmtoff)
1888 {
1889 	struct timespec *ts = NULL, tsb;
1890 
1891 	KASSERT(dep->de_flag & (DE_UPDATE | DE_CREATE | DE_ACCESS));
1892 	/* XXX just call getnanotime early and use result if needed? */
1893 	dep->de_flag |= DE_MODIFIED;
1894 	if (dep->de_flag & DE_UPDATE) {
1895 		if (mod == NULL) {
1896 			getnanotime(&tsb);
1897 			mod = ts = &tsb;
1898 		}
1899 		unix2dostime(mod, gmtoff, &dep->de_MDate, &dep->de_MTime, NULL);
1900 		dep->de_Attributes |= ATTR_ARCHIVE;
1901 	}
1902 	if ((dep->de_pmp->pm_flags & MSDOSFSMNT_NOWIN95) == 0) {
1903 		if (dep->de_flag & DE_ACCESS)  {
1904 			if (acc == NULL)
1905 				acc = ts == NULL ?
1906 				    (getnanotime(&tsb), ts = &tsb) : ts;
1907 			unix2dostime(acc, gmtoff, &dep->de_ADate, NULL, NULL);
1908 		}
1909 		if (dep->de_flag & DE_CREATE) {
1910 			if (cre == NULL)
1911 				cre = ts == NULL ?
1912 				    (getnanotime(&tsb), ts = &tsb) : ts;
1913 			unix2dostime(cre, gmtoff, &dep->de_CDate,
1914 			    &dep->de_CTime, &dep->de_CHun);
1915 		}
1916 	}
1917 
1918 	dep->de_flag &= ~(DE_UPDATE | DE_CREATE | DE_ACCESS);
1919 }
1920 
1921 /* Global vfs data structures for msdosfs */
1922 int (**msdosfs_vnodeop_p)(void *);
1923 const struct vnodeopv_entry_desc msdosfs_vnodeop_entries[] = {
1924 	{ &vop_default_desc, vn_default_error },
1925 	{ &vop_lookup_desc, msdosfs_lookup },		/* lookup */
1926 	{ &vop_create_desc, msdosfs_create },		/* create */
1927 	{ &vop_mknod_desc, msdosfs_mknod },		/* mknod */
1928 	{ &vop_open_desc, msdosfs_open },		/* open */
1929 	{ &vop_close_desc, msdosfs_close },		/* close */
1930 	{ &vop_access_desc, msdosfs_access },		/* access */
1931 	{ &vop_getattr_desc, msdosfs_getattr },		/* getattr */
1932 	{ &vop_setattr_desc, msdosfs_setattr },		/* setattr */
1933 	{ &vop_read_desc, msdosfs_read },		/* read */
1934 	{ &vop_write_desc, msdosfs_write },		/* write */
1935 	{ &vop_fcntl_desc, genfs_fcntl },		/* fcntl */
1936 	{ &vop_ioctl_desc, msdosfs_ioctl },		/* ioctl */
1937 	{ &vop_poll_desc, msdosfs_poll },		/* poll */
1938 	{ &vop_kqfilter_desc, genfs_kqfilter },		/* kqfilter */
1939 	{ &vop_revoke_desc, msdosfs_revoke },		/* revoke */
1940 	{ &vop_mmap_desc, msdosfs_mmap },		/* mmap */
1941 	{ &vop_fsync_desc, msdosfs_fsync },		/* fsync */
1942 	{ &vop_seek_desc, msdosfs_seek },		/* seek */
1943 	{ &vop_remove_desc, msdosfs_remove },		/* remove */
1944 	{ &vop_link_desc, msdosfs_link },		/* link */
1945 	{ &vop_rename_desc, msdosfs_rename },		/* rename */
1946 	{ &vop_mkdir_desc, msdosfs_mkdir },		/* mkdir */
1947 	{ &vop_rmdir_desc, msdosfs_rmdir },		/* rmdir */
1948 	{ &vop_symlink_desc, msdosfs_symlink },		/* symlink */
1949 	{ &vop_readdir_desc, msdosfs_readdir },		/* readdir */
1950 	{ &vop_readlink_desc, msdosfs_readlink },	/* readlink */
1951 	{ &vop_abortop_desc, msdosfs_abortop },		/* abortop */
1952 	{ &vop_inactive_desc, msdosfs_inactive },	/* inactive */
1953 	{ &vop_reclaim_desc, msdosfs_reclaim },		/* reclaim */
1954 	{ &vop_lock_desc, genfs_lock },			/* lock */
1955 	{ &vop_unlock_desc, genfs_unlock },		/* unlock */
1956 	{ &vop_bmap_desc, msdosfs_bmap },		/* bmap */
1957 	{ &vop_strategy_desc, msdosfs_strategy },	/* strategy */
1958 	{ &vop_print_desc, msdosfs_print },		/* print */
1959 	{ &vop_islocked_desc, genfs_islocked },		/* islocked */
1960 	{ &vop_pathconf_desc, msdosfs_pathconf },	/* pathconf */
1961 	{ &vop_advlock_desc, msdosfs_advlock },		/* advlock */
1962 	{ &vop_bwrite_desc, vn_bwrite },		/* bwrite */
1963 	{ &vop_getpages_desc, genfs_getpages },		/* getpages */
1964 	{ &vop_putpages_desc, genfs_putpages },		/* putpages */
1965 	{ NULL, NULL }
1966 };
1967 const struct vnodeopv_desc msdosfs_vnodeop_opv_desc =
1968 	{ &msdosfs_vnodeop_p, msdosfs_vnodeop_entries };
1969