xref: /dragonfly/sys/vfs/msdosfs/msdosfs_vnops.c (revision 8164c1fe)
1 /* $FreeBSD: src/sys/msdosfs/msdosfs_vnops.c,v 1.95.2.4 2003/06/13 15:05:47 trhodes Exp $ */
2 /* $DragonFly: src/sys/vfs/msdosfs/msdosfs_vnops.c,v 1.23 2005/02/15 08:32:18 joerg Exp $ */
3 /*	$NetBSD: msdosfs_vnops.c,v 1.68 1998/02/10 14:10:04 mrg Exp $	*/
4 
5 /*-
6  * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
7  * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
8  * All rights reserved.
9  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by TooLs GmbH.
22  * 4. The name of TooLs GmbH may not be used to endorse or promote products
23  *    derived from this software without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
29  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
30  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
31  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
32  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
33  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
34  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35  */
36 /*
37  * Written by Paul Popelka (paulp@uts.amdahl.com)
38  *
39  * You can do anything you want with this software, just don't say you wrote
40  * it, and don't remove this notice.
41  *
42  * This software is provided "as is".
43  *
44  * The author supplies this software to be publicly redistributed on the
45  * understanding that the author is not responsible for the correct
46  * functioning of this software in any circumstances and is not liable for
47  * any damages caused by this software.
48  *
49  * October 1992
50  */
51 
52 #include <sys/param.h>
53 #include <sys/systm.h>
54 #include <sys/resourcevar.h>	/* defines plimit structure in proc struct */
55 #include <sys/kernel.h>
56 #include <sys/stat.h>
57 #include <sys/buf.h>
58 #include <sys/proc.h>
59 #include <sys/namei.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/vm_zone.h>
70 #include <vm/vnode_pager.h>
71 
72 #include <sys/buf2.h>
73 
74 #include "bpb.h"
75 #include "direntry.h"
76 #include "denode.h"
77 #include "msdosfsmount.h"
78 #include "fat.h"
79 
80 #define	DOS_FILESIZE_MAX	0xffffffff
81 
82 /*
83  * Prototypes for MSDOSFS vnode operations
84  */
85 static int msdosfs_create (struct vop_create_args *);
86 static int msdosfs_mknod (struct vop_mknod_args *);
87 static int msdosfs_close (struct vop_close_args *);
88 static int msdosfs_access (struct vop_access_args *);
89 static int msdosfs_getattr (struct vop_getattr_args *);
90 static int msdosfs_setattr (struct vop_setattr_args *);
91 static int msdosfs_read (struct vop_read_args *);
92 static int msdosfs_write (struct vop_write_args *);
93 static int msdosfs_fsync (struct vop_fsync_args *);
94 static int msdosfs_remove (struct vop_remove_args *);
95 static int msdosfs_link (struct vop_link_args *);
96 static int msdosfs_rename (struct vop_rename_args *);
97 static int msdosfs_mkdir (struct vop_mkdir_args *);
98 static int msdosfs_rmdir (struct vop_rmdir_args *);
99 static int msdosfs_symlink (struct vop_symlink_args *);
100 static int msdosfs_readdir (struct vop_readdir_args *);
101 static int msdosfs_bmap (struct vop_bmap_args *);
102 static int msdosfs_strategy (struct vop_strategy_args *);
103 static int msdosfs_print (struct vop_print_args *);
104 static int msdosfs_pathconf (struct vop_pathconf_args *ap);
105 static int msdosfs_getpages (struct vop_getpages_args *);
106 static int msdosfs_putpages (struct vop_putpages_args *);
107 
108 /*
109  * Some general notes:
110  *
111  * In the ufs filesystem the inodes, superblocks, and indirect blocks are
112  * read/written using the vnode for the filesystem. Blocks that represent
113  * the contents of a file are read/written using the vnode for the file
114  * (including directories when they are read/written as files). This
115  * presents problems for the dos filesystem because data that should be in
116  * an inode (if dos had them) resides in the directory itself.  Since we
117  * must update directory entries without the benefit of having the vnode
118  * for the directory we must use the vnode for the filesystem.  This means
119  * that when a directory is actually read/written (via read, write, or
120  * readdir, or seek) we must use the vnode for the filesystem instead of
121  * the vnode for the directory as would happen in ufs. This is to insure we
122  * retreive the correct block from the buffer cache since the hash value is
123  * based upon the vnode address and the desired block number.
124  */
125 
126 /*
127  * Create a regular file. On entry the directory to contain the file being
128  * created is locked.  We must release before we return.
129  *
130  * msdosfs_create(struct vnode *a_dvp, struct vnode **a_vpp,
131  *		  struct componentname *a_cnp, struct vattr *a_vap)
132  */
133 static int
134 msdosfs_create(struct vop_create_args *ap)
135 {
136 	struct componentname *cnp = ap->a_cnp;
137 	struct denode ndirent;
138 	struct denode *dep;
139 	struct denode *pdep = VTODE(ap->a_dvp);
140 	struct timespec ts;
141 	int error;
142 
143 #ifdef MSDOSFS_DEBUG
144 	printf("msdosfs_create(cnp %p, vap %p\n", cnp, ap->a_vap);
145 #endif
146 
147 	/*
148 	 * If this is the root directory and there is no space left we
149 	 * can't do anything.  This is because the root directory can not
150 	 * change size.
151 	 */
152 	if (pdep->de_StartCluster == MSDOSFSROOT
153 	    && pdep->de_fndoffset >= pdep->de_FileSize) {
154 		error = ENOSPC;
155 		goto bad;
156 	}
157 
158 	/*
159 	 * Create a directory entry for the file, then call createde() to
160 	 * have it installed. NOTE: DOS files are always executable.  We
161 	 * use the absence of the owner write bit to make the file
162 	 * readonly.
163 	 */
164 	bzero(&ndirent, sizeof(ndirent));
165 	error = uniqdosname(pdep, cnp, ndirent.de_Name);
166 	if (error)
167 		goto bad;
168 
169 	ndirent.de_Attributes = (ap->a_vap->va_mode & VWRITE) ?
170 				ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY;
171 	ndirent.de_LowerCase = 0;
172 	ndirent.de_StartCluster = 0;
173 	ndirent.de_FileSize = 0;
174 	ndirent.de_dev = pdep->de_dev;
175 	ndirent.de_devvp = pdep->de_devvp;
176 	ndirent.de_pmp = pdep->de_pmp;
177 	ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
178 	getnanotime(&ts);
179 	DETIMES(&ndirent, &ts, &ts, &ts);
180 	error = createde(&ndirent, pdep, &dep, cnp);
181 	if (error)
182 		goto bad;
183 	*ap->a_vpp = DETOV(dep);
184 	return (0);
185 
186 bad:
187 	return (error);
188 }
189 
190 /*
191  * msdosfs_mknod(struct vnode *a_dvp, struct vnode **a_vpp,
192  *		 struct componentname *a_cnp, struct vattr *a_vap)
193  */
194 static int
195 msdosfs_mknod(struct vop_mknod_args *ap)
196 {
197 	switch (ap->a_vap->va_type) {
198 	case VDIR:
199 		return (msdosfs_mkdir((struct vop_mkdir_args *)ap));
200 		break;
201 
202 	case VREG:
203 		return (msdosfs_create((struct vop_create_args *)ap));
204 		break;
205 
206 	default:
207 		return (EINVAL);
208 	}
209 	/* NOTREACHED */
210 }
211 
212 /*
213  * msdosfs_close(struct vnode *a_vp, int a_fflag, struct ucred *a_cred,
214  *		 struct thread *a_td)
215  */
216 static int
217 msdosfs_close(struct vop_close_args *ap)
218 {
219 	struct vnode *vp = ap->a_vp;
220 	struct denode *dep = VTODE(vp);
221 	struct timespec ts;
222 
223 	if (vp->v_usecount > 1) {
224 		getnanotime(&ts);
225 		if (vp->v_usecount > 1) {
226 			DETIMES(dep, &ts, &ts, &ts);
227 		}
228 	}
229 	return 0;
230 }
231 
232 /*
233  * msdosfs_access(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
234  *		  struct thread *a_td)
235  */
236 static int
237 msdosfs_access(struct vop_access_args *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 	struct ucred *cred = ap->a_cred;
243 	mode_t mask, file_mode, mode = ap->a_mode;
244 	gid_t *gp;
245 	int i;
246 
247 	file_mode = (S_IXUSR|S_IXGRP|S_IXOTH) | (S_IRUSR|S_IRGRP|S_IROTH) |
248 	    ((dep->de_Attributes & ATTR_READONLY) ? 0 : (S_IWUSR|S_IWGRP|S_IWOTH));
249 	file_mode &= pmp->pm_mask;
250 
251 	/*
252 	 * Disallow write attempts on read-only file systems;
253 	 * unless the file is a socket, fifo, or a block or
254 	 * character device resident on the file system.
255 	 */
256 	if (mode & VWRITE) {
257 		switch (vp->v_type) {
258 		case VDIR:
259 		case VLNK:
260 		case VREG:
261 			if (vp->v_mount->mnt_flag & MNT_RDONLY)
262 				return (EROFS);
263 			break;
264 		default:
265 			break;
266 		}
267 	}
268 
269 	/* User id 0 always gets access. */
270 	if (cred->cr_uid == 0)
271 		return 0;
272 
273 	mask = 0;
274 
275 	/* Otherwise, check the owner. */
276 	if (cred->cr_uid == pmp->pm_uid) {
277 		if (mode & VEXEC)
278 			mask |= S_IXUSR;
279 		if (mode & VREAD)
280 			mask |= S_IRUSR;
281 		if (mode & VWRITE)
282 			mask |= S_IWUSR;
283 		return (file_mode & mask) == mask ? 0 : EACCES;
284 	}
285 
286 	/* Otherwise, check the groups. */
287 	for (i = 0, gp = cred->cr_groups; i < cred->cr_ngroups; i++, gp++)
288 		if (pmp->pm_gid == *gp) {
289 			if (mode & VEXEC)
290 				mask |= S_IXGRP;
291 			if (mode & VREAD)
292 				mask |= S_IRGRP;
293 			if (mode & VWRITE)
294 				mask |= S_IWGRP;
295 			return (file_mode & mask) == mask ? 0 : EACCES;
296 		}
297 
298 	/* Otherwise, check everyone else. */
299 	if (mode & VEXEC)
300 		mask |= S_IXOTH;
301 	if (mode & VREAD)
302 		mask |= S_IROTH;
303 	if (mode & VWRITE)
304 		mask |= S_IWOTH;
305 	return (file_mode & mask) == mask ? 0 : EACCES;
306 }
307 
308 /*
309  * msdosfs_getattr(struct vnode *a_vp, struct vattr *a_vap,
310  *		   struct ucred *a_cred, struct thread *a_td)
311  */
312 static int
313 msdosfs_getattr(struct vop_getattr_args *ap)
314 {
315 	struct denode *dep = VTODE(ap->a_vp);
316 	struct msdosfsmount *pmp = dep->de_pmp;
317 	struct vattr *vap = ap->a_vap;
318 	mode_t mode;
319 	struct timespec ts;
320 	u_long dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
321 	u_long fileid;
322 
323 	getnanotime(&ts);
324 	DETIMES(dep, &ts, &ts, &ts);
325 	vap->va_fsid = dev2udev(dep->de_dev);
326 	/*
327 	 * The following computation of the fileid must be the same as that
328 	 * used in msdosfs_readdir() to compute d_fileno. If not, pwd
329 	 * doesn't work.
330 	 */
331 	if (dep->de_Attributes & ATTR_DIRECTORY) {
332 		fileid = cntobn(pmp, dep->de_StartCluster) * dirsperblk;
333 		if (dep->de_StartCluster == MSDOSFSROOT)
334 			fileid = 1;
335 	} else {
336 		fileid = cntobn(pmp, dep->de_dirclust) * dirsperblk;
337 		if (dep->de_dirclust == MSDOSFSROOT)
338 			fileid = roottobn(pmp, 0) * dirsperblk;
339 		fileid += dep->de_diroffset / sizeof(struct direntry);
340 	}
341 	vap->va_fileid = fileid;
342 	if ((dep->de_Attributes & ATTR_READONLY) == 0)
343 		mode = S_IRWXU|S_IRWXG|S_IRWXO;
344 	else
345 		mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
346 	vap->va_mode = mode & pmp->pm_mask;
347 	vap->va_uid = pmp->pm_uid;
348 	vap->va_gid = pmp->pm_gid;
349 	vap->va_nlink = 1;
350 	vap->va_rdev = 0;
351 	vap->va_size = dep->de_FileSize;
352 	dos2unixtime(dep->de_MDate, dep->de_MTime, 0, &vap->va_mtime);
353 	if (pmp->pm_flags & MSDOSFSMNT_LONGNAME) {
354 		dos2unixtime(dep->de_ADate, 0, 0, &vap->va_atime);
355 		dos2unixtime(dep->de_CDate, dep->de_CTime, dep->de_CHun, &vap->va_ctime);
356 	} else {
357 		vap->va_atime = vap->va_mtime;
358 		vap->va_ctime = vap->va_mtime;
359 	}
360 	vap->va_flags = 0;
361 	if ((dep->de_Attributes & ATTR_ARCHIVE) == 0)
362 		vap->va_flags |= SF_ARCHIVED;
363 	vap->va_gen = 0;
364 	vap->va_blocksize = pmp->pm_bpcluster;
365 	vap->va_bytes =
366 	    (dep->de_FileSize + pmp->pm_crbomask) & ~pmp->pm_crbomask;
367 	vap->va_type = ap->a_vp->v_type;
368 	vap->va_filerev = dep->de_modrev;
369 	return (0);
370 }
371 
372 /*
373  * msdosfs_setattr(struct vnode *a_vp, struct vattr *a_vap,
374  *		   struct ucred *a_cred, struct thread *a_td)
375  */
376 static int
377 msdosfs_setattr(struct vop_setattr_args *ap)
378 {
379 	struct vnode *vp = ap->a_vp;
380 	struct denode *dep = VTODE(ap->a_vp);
381 	struct msdosfsmount *pmp = dep->de_pmp;
382 	struct vattr *vap = ap->a_vap;
383 	struct ucred *cred = ap->a_cred;
384 	int error = 0;
385 
386 #ifdef MSDOSFS_DEBUG
387 	printf("msdosfs_setattr(): vp %p, vap %p, cred %p, p %p\n",
388 	    ap->a_vp, vap, cred, ap->a_td);
389 #endif
390 
391 	/*
392 	 * Check for unsettable attributes.
393 	 */
394 	if ((vap->va_type != VNON) || (vap->va_nlink != VNOVAL) ||
395 	    (vap->va_fsid != VNOVAL) || (vap->va_fileid != VNOVAL) ||
396 	    (vap->va_blocksize != VNOVAL) || (vap->va_rdev != VNOVAL) ||
397 	    (vap->va_bytes != VNOVAL) || (vap->va_gen != VNOVAL)) {
398 #ifdef MSDOSFS_DEBUG
399 		printf("msdosfs_setattr(): returning EINVAL\n");
400 		printf("    va_type %d, va_nlink %x, va_fsid %lx, va_fileid %lx\n",
401 		    vap->va_type, vap->va_nlink, vap->va_fsid, vap->va_fileid);
402 		printf("    va_blocksize %lx, va_rdev %x, va_bytes %qx, va_gen %lx\n",
403 		    vap->va_blocksize, vap->va_rdev, vap->va_bytes, vap->va_gen);
404 		printf("    va_uid %x, va_gid %x\n",
405 		    vap->va_uid, vap->va_gid);
406 #endif
407 		return (EINVAL);
408 	}
409 	if (vap->va_flags != VNOVAL) {
410 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
411 			return (EROFS);
412 		if (cred->cr_uid != pmp->pm_uid &&
413 		    (error = suser_cred(cred, PRISON_ROOT)))
414 			return (error);
415 		/*
416 		 * We are very inconsistent about handling unsupported
417 		 * attributes.  We ignored the access time and the
418 		 * read and execute bits.  We were strict for the other
419 		 * attributes.
420 		 *
421 		 * Here we are strict, stricter than ufs in not allowing
422 		 * users to attempt to set SF_SETTABLE bits or anyone to
423 		 * set unsupported bits.  However, we ignore attempts to
424 		 * set ATTR_ARCHIVE for directories `cp -pr' from a more
425 		 * sensible file system attempts it a lot.
426 		 */
427 		if (cred->cr_uid != 0) {
428 			if (vap->va_flags & SF_SETTABLE)
429 				return EPERM;
430 		}
431 		if (vap->va_flags & ~SF_ARCHIVED)
432 			return EOPNOTSUPP;
433 		if (vap->va_flags & SF_ARCHIVED)
434 			dep->de_Attributes &= ~ATTR_ARCHIVE;
435 		else if (!(dep->de_Attributes & ATTR_DIRECTORY))
436 			dep->de_Attributes |= ATTR_ARCHIVE;
437 		dep->de_flag |= DE_MODIFIED;
438 	}
439 
440 	if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
441 		uid_t uid;
442 		gid_t gid;
443 
444 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
445 			return (EROFS);
446 		uid = vap->va_uid;
447 		if (uid == (uid_t)VNOVAL)
448 			uid = pmp->pm_uid;
449 		gid = vap->va_gid;
450 		if (gid == (gid_t)VNOVAL)
451 			gid = pmp->pm_gid;
452 		if ((cred->cr_uid != pmp->pm_uid || uid != pmp->pm_uid ||
453 		    (gid != pmp->pm_gid && !groupmember(gid, cred))) &&
454 		    (error = suser_cred(cred, PRISON_ROOT)))
455 			return error;
456 		if (uid != pmp->pm_uid || gid != pmp->pm_gid)
457 			return EINVAL;
458 	}
459 
460 	if (vap->va_size != VNOVAL) {
461 		/*
462 		 * Disallow write attempts on read-only file systems;
463 		 * unless the file is a socket, fifo, or a block or
464 		 * character device resident on the file system.
465 		 */
466 		switch (vp->v_type) {
467 		case VDIR:
468 			return (EISDIR);
469 			/* NOT REACHED */
470 		case VLNK:
471 		case VREG:
472 			if (vp->v_mount->mnt_flag & MNT_RDONLY)
473 				return (EROFS);
474 			break;
475 		default:
476 			break;
477 		}
478 		error = detrunc(dep, vap->va_size, 0, ap->a_td);
479 		if (error)
480 			return error;
481 	}
482 	if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
483 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
484 			return (EROFS);
485 		if (cred->cr_uid != pmp->pm_uid &&
486 		    (error = suser_cred(cred, PRISON_ROOT)) &&
487 		    ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
488 		    (error = VOP_ACCESS(ap->a_vp, VWRITE, cred, ap->a_td))))
489 			return (error);
490 		if (vp->v_type != VDIR) {
491 			if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) == 0 &&
492 			    vap->va_atime.tv_sec != VNOVAL) {
493 				dep->de_flag &= ~DE_ACCESS;
494 				unix2dostime(&vap->va_atime, &dep->de_ADate,
495 				    NULL, NULL);
496 			}
497 			if (vap->va_mtime.tv_sec != VNOVAL) {
498 				dep->de_flag &= ~DE_UPDATE;
499 				unix2dostime(&vap->va_mtime, &dep->de_MDate,
500 				    &dep->de_MTime, NULL);
501 			}
502 			dep->de_Attributes |= ATTR_ARCHIVE;
503 			dep->de_flag |= DE_MODIFIED;
504 		}
505 	}
506 	/*
507 	 * DOS files only have the ability to have their writability
508 	 * attribute set, so we use the owner write bit to set the readonly
509 	 * attribute.
510 	 */
511 	if (vap->va_mode != (mode_t)VNOVAL) {
512 		if (vp->v_mount->mnt_flag & MNT_RDONLY)
513 			return (EROFS);
514 		if (cred->cr_uid != pmp->pm_uid &&
515 		    (error = suser_cred(cred, PRISON_ROOT)))
516 			return (error);
517 		if (vp->v_type != VDIR) {
518 			/* We ignore the read and execute bits. */
519 			if (vap->va_mode & VWRITE)
520 				dep->de_Attributes &= ~ATTR_READONLY;
521 			else
522 				dep->de_Attributes |= ATTR_READONLY;
523 			dep->de_Attributes |= ATTR_ARCHIVE;
524 			dep->de_flag |= DE_MODIFIED;
525 		}
526 	}
527 	return (deupdat(dep, 1));
528 }
529 
530 /*
531  * msdosfs_read(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
532  *		struct ucred *a_cred)
533  */
534 static int
535 msdosfs_read(struct vop_read_args *ap)
536 {
537 	int error = 0;
538 	int blsize;
539 	int isadir;
540 	int orig_resid;
541 	u_int n;
542 	u_long diff;
543 	u_long on;
544 	daddr_t lbn;
545 	daddr_t rablock;
546 	int rasize;
547 	int seqcount;
548 	struct buf *bp;
549 	struct vnode *vp = ap->a_vp;
550 	struct denode *dep = VTODE(vp);
551 	struct msdosfsmount *pmp = dep->de_pmp;
552 	struct uio *uio = ap->a_uio;
553 
554 	if (uio->uio_offset < 0)
555 		return (EINVAL);
556 
557 	if ((uoff_t)uio->uio_offset > DOS_FILESIZE_MAX)
558                 return (0);
559 	/*
560 	 * If they didn't ask for any data, then we are done.
561 	 */
562 	orig_resid = uio->uio_resid;
563 	if (orig_resid <= 0)
564 		return (0);
565 
566 	seqcount = ap->a_ioflag >> IO_SEQSHIFT;
567 
568 	isadir = dep->de_Attributes & ATTR_DIRECTORY;
569 	do {
570 		if (uio->uio_offset >= dep->de_FileSize)
571 			break;
572 		lbn = de_cluster(pmp, uio->uio_offset);
573 		/*
574 		 * If we are operating on a directory file then be sure to
575 		 * do i/o with the vnode for the filesystem instead of the
576 		 * vnode for the directory.
577 		 */
578 		if (isadir) {
579 			/* convert cluster # to block # */
580 			error = pcbmap(dep, lbn, &lbn, 0, &blsize);
581 			if (error == E2BIG) {
582 				error = EINVAL;
583 				break;
584 			} else if (error)
585 				break;
586 			error = bread(pmp->pm_devvp, lbn, blsize, &bp);
587 		} else {
588 			blsize = pmp->pm_bpcluster;
589 			rablock = lbn + 1;
590 			if (seqcount > 1 &&
591 			    de_cn2off(pmp, rablock) < dep->de_FileSize) {
592 				rasize = pmp->pm_bpcluster;
593 				error = breadn(vp, lbn, blsize,
594 				    &rablock, &rasize, 1, &bp);
595 			} else {
596 				error = bread(vp, lbn, blsize, &bp);
597 			}
598 		}
599 		if (error) {
600 			brelse(bp);
601 			break;
602 		}
603 		on = uio->uio_offset & pmp->pm_crbomask;
604 		diff = pmp->pm_bpcluster - on;
605 		n = diff > uio->uio_resid ? uio->uio_resid : diff;
606 		diff = dep->de_FileSize - uio->uio_offset;
607 		if (diff < n)
608 			n = diff;
609 		diff = blsize - bp->b_resid;
610 		if (diff < n)
611 			n = diff;
612 		error = uiomove(bp->b_data + on, (int) n, uio);
613 		brelse(bp);
614 	} while (error == 0 && uio->uio_resid > 0 && n != 0);
615 	if (!isadir && (error == 0 || uio->uio_resid != orig_resid) &&
616 	    (vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
617 		dep->de_flag |= DE_ACCESS;
618 	return (error);
619 }
620 
621 /*
622  * Write data to a file or directory.
623  *
624  * msdosfs_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
625  *		 struct ucred *a_cred)
626  */
627 static int
628 msdosfs_write(struct vop_write_args *ap)
629 {
630 	int n;
631 	int croffset;
632 	int resid;
633 	u_long osize;
634 	int error = 0;
635 	u_long count;
636 	daddr_t bn, lastcn;
637 	struct buf *bp;
638 	int ioflag = ap->a_ioflag;
639 	struct uio *uio = ap->a_uio;
640 	struct thread *td = uio->uio_td;
641 	struct vnode *vp = ap->a_vp;
642 	struct vnode *thisvp;
643 	struct denode *dep = VTODE(vp);
644 	struct msdosfsmount *pmp = dep->de_pmp;
645 	struct proc *p = (td ? td->td_proc : NULL);
646 
647 #ifdef MSDOSFS_DEBUG
648 	printf("msdosfs_write(vp %p, uio %p, ioflag %x, cred %p\n",
649 	    vp, uio, ioflag, cred);
650 	printf("msdosfs_write(): diroff %lu, dirclust %lu, startcluster %lu\n",
651 	    dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster);
652 #endif
653 
654 	switch (vp->v_type) {
655 	case VREG:
656 		if (ioflag & IO_APPEND)
657 			uio->uio_offset = dep->de_FileSize;
658 		thisvp = vp;
659 		break;
660 	case VDIR:
661 		return EISDIR;
662 	default:
663 		panic("msdosfs_write(): bad file type");
664 	}
665 
666 	if (uio->uio_offset < 0)
667 		return (EFBIG);
668 
669 	if (uio->uio_resid == 0)
670 		return (0);
671 
672 	/*
673 	 * If they've exceeded their filesize limit, tell them about it.
674 	 */
675 	if (p &&
676 	    ((uoff_t)uio->uio_offset + uio->uio_resid >
677 	    p->p_rlimit[RLIMIT_FSIZE].rlim_cur)) {
678 		psignal(p, SIGXFSZ);
679 		return (EFBIG);
680 	}
681 
682 	if ((uoff_t)uio->uio_offset + uio->uio_resid > DOS_FILESIZE_MAX)
683                 return (EFBIG);
684 
685 	/*
686 	 * If the offset we are starting the write at is beyond the end of
687 	 * the file, then they've done a seek.  Unix filesystems allow
688 	 * files with holes in them, DOS doesn't so we must fill the hole
689 	 * with zeroed blocks.
690 	 */
691 	if (uio->uio_offset > dep->de_FileSize) {
692 		error = deextend(dep, uio->uio_offset);
693 		if (error)
694 			return (error);
695 	}
696 
697 	/*
698 	 * Remember some values in case the write fails.
699 	 */
700 	resid = uio->uio_resid;
701 	osize = dep->de_FileSize;
702 
703 	/*
704 	 * If we write beyond the end of the file, extend it to its ultimate
705 	 * size ahead of the time to hopefully get a contiguous area.
706 	 */
707 	if (uio->uio_offset + resid > osize) {
708 		count = de_clcount(pmp, uio->uio_offset + resid) -
709 			de_clcount(pmp, osize);
710 		error = extendfile(dep, count, NULL, NULL, 0);
711 		if (error &&  (error != ENOSPC || (ioflag & IO_UNIT)))
712 			goto errexit;
713 		lastcn = dep->de_fc[FC_LASTFC].fc_frcn;
714 	} else
715 		lastcn = de_clcount(pmp, osize) - 1;
716 
717 	do {
718 		if (de_cluster(pmp, uio->uio_offset) > lastcn) {
719 			error = ENOSPC;
720 			break;
721 		}
722 
723 		croffset = uio->uio_offset & pmp->pm_crbomask;
724 		n = min(uio->uio_resid, pmp->pm_bpcluster - croffset);
725 		if (uio->uio_offset + n > dep->de_FileSize) {
726 			dep->de_FileSize = uio->uio_offset + n;
727 			/* The object size needs to be set before buffer is allocated */
728 			vnode_pager_setsize(vp, dep->de_FileSize);
729 		}
730 
731 		bn = de_cluster(pmp, uio->uio_offset);
732 		if ((uio->uio_offset & pmp->pm_crbomask) == 0
733 		    && (de_cluster(pmp, uio->uio_offset + uio->uio_resid)
734 		        > de_cluster(pmp, uio->uio_offset)
735 			|| uio->uio_offset + uio->uio_resid >= dep->de_FileSize)) {
736 			/*
737 			 * If either the whole cluster gets written,
738 			 * or we write the cluster from its start beyond EOF,
739 			 * then no need to read data from disk.
740 			 */
741 			bp = getblk(thisvp, bn, pmp->pm_bpcluster, 0, 0);
742 			clrbuf(bp);
743 			/*
744 			 * Do the bmap now, since pcbmap needs buffers
745 			 * for the fat table. (see msdosfs_strategy)
746 			 */
747 			if (bp->b_blkno == bp->b_lblkno) {
748 				error = pcbmap(dep, bp->b_lblkno, &bp->b_blkno,
749 				     0, 0);
750 				if (error)
751 					bp->b_blkno = -1;
752 			}
753 			if (bp->b_blkno == -1) {
754 				brelse(bp);
755 				if (!error)
756 					error = EIO;		/* XXX */
757 				break;
758 			}
759 		} else {
760 			/*
761 			 * The block we need to write into exists, so read it in.
762 			 */
763 			error = bread(thisvp, bn, pmp->pm_bpcluster, &bp);
764 			if (error) {
765 				brelse(bp);
766 				break;
767 			}
768 		}
769 
770 		/*
771 		 * Should these vnode_pager_* functions be done on dir
772 		 * files?
773 		 */
774 
775 		/*
776 		 * Copy the data from user space into the buf header.
777 		 */
778 		error = uiomove(bp->b_data + croffset, n, uio);
779 		if (error) {
780 			brelse(bp);
781 			break;
782 		}
783 
784 		/*
785 		 * If they want this synchronous then write it and wait for
786 		 * it.  Otherwise, if on a cluster boundary write it
787 		 * asynchronously so we can move on to the next block
788 		 * without delay.  Otherwise do a delayed write because we
789 		 * may want to write somemore into the block later.
790 		 */
791 		if (ioflag & IO_SYNC)
792 			(void) bwrite(bp);
793 		else if (n + croffset == pmp->pm_bpcluster)
794 			bawrite(bp);
795 		else
796 			bdwrite(bp);
797 		dep->de_flag |= DE_UPDATE;
798 	} while (error == 0 && uio->uio_resid > 0);
799 
800 	/*
801 	 * If the write failed and they want us to, truncate the file back
802 	 * to the size it was before the write was attempted.
803 	 */
804 errexit:
805 	if (error) {
806 		if (ioflag & IO_UNIT) {
807 			detrunc(dep, osize, ioflag & IO_SYNC, NULL);
808 			uio->uio_offset -= resid - uio->uio_resid;
809 			uio->uio_resid = resid;
810 		} else {
811 			detrunc(dep, dep->de_FileSize, ioflag & IO_SYNC, NULL);
812 			if (uio->uio_resid != resid)
813 				error = 0;
814 		}
815 	} else if (ioflag & IO_SYNC)
816 		error = deupdat(dep, 1);
817 	return (error);
818 }
819 
820 /*
821  * Flush the blocks of a file to disk.
822  *
823  * This function is worthless for vnodes that represent directories. Maybe we
824  * could just do a sync if they try an fsync on a directory file.
825  *
826  * msdosfs_fsync(struct vnode *a_vp, struct ucred *a_cred, int a_waitfor,
827  *		 struct thread *a_td)
828  */
829 static int
830 msdosfs_fsync(struct vop_fsync_args *ap)
831 {
832 	struct vnode *vp = ap->a_vp;
833 	int s;
834 	struct buf *bp, *nbp;
835 
836 	/*
837 	 * Flush all dirty buffers associated with a vnode.
838 	 */
839 loop:
840 	s = splbio();
841 	for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
842 		nbp = TAILQ_NEXT(bp, b_vnbufs);
843 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT))
844 			continue;
845 		if ((bp->b_flags & B_DELWRI) == 0)
846 			panic("msdosfs_fsync: not dirty");
847 		bremfree(bp);
848 		splx(s);
849 		(void) bwrite(bp);
850 		goto loop;
851 	}
852 	while (vp->v_numoutput) {
853 		vp->v_flag |= VBWAIT;
854 		(void) tsleep((caddr_t)&vp->v_numoutput, 0, "msdosfsn", 0);
855 	}
856 #ifdef DIAGNOSTIC
857 	if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
858 		vprint("msdosfs_fsync: dirty", vp);
859 		goto loop;
860 	}
861 #endif
862 	splx(s);
863 	return (deupdat(VTODE(vp), ap->a_waitfor == MNT_WAIT));
864 }
865 
866 /*
867  * msdosfs_remove(struct vnode *a_dvp, struct vnode *a_vp,
868  *		  struct componentname *a_cnp)
869  */
870 static int
871 msdosfs_remove(struct vop_remove_args *ap)
872 {
873 	struct denode *dep = VTODE(ap->a_vp);
874 	struct denode *ddep = VTODE(ap->a_dvp);
875 	int error;
876 
877 	if (ap->a_vp->v_type == VDIR)
878 		error = EPERM;
879 	else
880 		error = removede(ddep, dep);
881 #ifdef MSDOSFS_DEBUG
882 	printf("msdosfs_remove(), dep %p, v_usecount %d\n", dep, ap->a_vp->v_usecount);
883 #endif
884 	return (error);
885 }
886 
887 /*
888  * DOS filesystems don't know what links are. But since we already called
889  * msdosfs_lookup() with create and lockparent, the parent is locked so we
890  * have to free it before we return the error.
891  *
892  * msdosfs_link(struct vnode *a_tdvp, struct vnode *a_vp,
893  *		struct componentname *a_cnp)
894  */
895 static int
896 msdosfs_link(struct vop_link_args *ap)
897 {
898 	return (EOPNOTSUPP);
899 }
900 
901 /*
902  * Renames on files require moving the denode to a new hash queue since the
903  * denode's location is used to compute which hash queue to put the file
904  * in. Unless it is a rename in place.  For example "mv a b".
905  *
906  * What follows is the basic algorithm:
907  *
908  * if (file move) {
909  *	if (dest file exists) {
910  *		remove dest file
911  *	}
912  *	if (dest and src in same directory) {
913  *		rewrite name in existing directory slot
914  *	} else {
915  *		write new entry in dest directory
916  *		update offset and dirclust in denode
917  *		move denode to new hash chain
918  *		clear old directory entry
919  *	}
920  * } else {
921  *	directory move
922  *	if (dest directory exists) {
923  *		if (dest is not empty) {
924  *			return ENOTEMPTY
925  *		}
926  *		remove dest directory
927  *	}
928  *	if (dest and src in same directory) {
929  *		rewrite name in existing entry
930  *	} else {
931  *		be sure dest is not a child of src directory
932  *		write entry in dest directory
933  *		update "." and ".." in moved directory
934  *		clear old directory entry for moved directory
935  *	}
936  * }
937  *
938  * On entry:
939  *	source's parent directory is unlocked
940  *	source file or directory is unlocked
941  *	destination's parent directory is locked
942  *	destination file or directory is locked if it exists
943  *
944  * On exit:
945  *	all denodes should be released
946  *
947  * Notes:
948  * I'm not sure how the memory containing the pathnames pointed at by the
949  * componentname structures is freed, there may be some memory bleeding
950  * for each rename done.
951  *
952  * msdosfs_rename(struct vnode *a_fdvp, struct vnode *a_fvp,
953  *		  struct componentname *a_fcnp, struct vnode *a_tdvp,
954  *		  struct vnode *a_tvp, struct componentname *a_tcnp)
955  */
956 static int
957 msdosfs_rename(struct vop_rename_args *ap)
958 {
959 	struct vnode *tdvp = ap->a_tdvp;
960 	struct vnode *fvp = ap->a_fvp;
961 	struct vnode *fdvp = ap->a_fdvp;
962 	struct vnode *tvp = ap->a_tvp;
963 	struct componentname *tcnp = ap->a_tcnp;
964 	struct componentname *fcnp = ap->a_fcnp;
965 	struct thread *td = fcnp->cn_td;
966 	struct denode *ip, *xp, *dp, *zp;
967 	u_char toname[11], oldname[11];
968 	u_long from_diroffset, to_diroffset;
969 	u_char to_count;
970 	int doingdirectory = 0, newparent = 0;
971 	int error;
972 	u_long cn;
973 	daddr_t bn;
974 	struct denode *fddep;	/* from file's parent directory	 */
975 	struct msdosfsmount *pmp;
976 	struct direntry *dotdotp;
977 	struct buf *bp;
978 
979 	fddep = VTODE(ap->a_fdvp);
980 	pmp = fddep->de_pmp;
981 
982 	pmp = VFSTOMSDOSFS(fdvp->v_mount);
983 
984 	/*
985 	 * Check for cross-device rename.
986 	 */
987 	if ((fvp->v_mount != tdvp->v_mount) ||
988 	    (tvp && (fvp->v_mount != tvp->v_mount))) {
989 		error = EXDEV;
990 abortit:
991 		if (tdvp == tvp)
992 			vrele(tdvp);
993 		else
994 			vput(tdvp);
995 		if (tvp)
996 			vput(tvp);
997 		vrele(fdvp);
998 		vrele(fvp);
999 		return (error);
1000 	}
1001 
1002 	/*
1003 	 * If source and dest are the same, do nothing.
1004 	 */
1005 	if (tvp == fvp) {
1006 		error = 0;
1007 		goto abortit;
1008 	}
1009 
1010 	/*
1011 	 * fvp, fdvp are unlocked, tvp, tdvp are locked.  Lock fvp and note
1012 	 * that we have to unlock it to use the abortit target.
1013 	 */
1014 	error = vn_lock(fvp, LK_EXCLUSIVE, td);
1015 	if (error)
1016 		goto abortit;
1017 	dp = VTODE(fdvp);
1018 	ip = VTODE(fvp);
1019 
1020 	/*
1021 	 * Be sure we are not renaming ".", "..", or an alias of ".". This
1022 	 * leads to a crippled directory tree.  It's pretty tough to do a
1023 	 * "ls" or "pwd" with the "." directory entry missing, and "cd .."
1024 	 * doesn't work if the ".." entry is missing.
1025 	 */
1026 	if (ip->de_Attributes & ATTR_DIRECTORY) {
1027 		/*
1028 		 * Avoid ".", "..", and aliases of "." for obvious reasons.
1029 		 */
1030 		if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
1031 		    dp == ip ||
1032 		    (fcnp->cn_flags & CNP_ISDOTDOT) ||
1033 		    (tcnp->cn_flags & CNP_ISDOTDOT) ||
1034 		    (ip->de_flag & DE_RENAME)) {
1035 			VOP_UNLOCK(fvp, 0, td);
1036 			error = EINVAL;
1037 			goto abortit;
1038 		}
1039 		ip->de_flag |= DE_RENAME;
1040 		doingdirectory++;
1041 	}
1042 
1043 	/*
1044 	 * fvp locked, fdvp unlocked, tvp, tdvp locked.  DE_RENAME only
1045 	 * set if doingdirectory.  We will get fvp unlocked in fairly
1046 	 * short order.  dp and xp must be setup and fvp must be unlocked
1047 	 * for the out and bad targets to work properly.
1048 	 */
1049 	dp = VTODE(tdvp);
1050 	xp = tvp ? VTODE(tvp) : NULL;
1051 
1052 	/*
1053 	 * Remember direntry place to use for destination
1054 	 */
1055 	to_diroffset = dp->de_fndoffset;
1056 	to_count = dp->de_fndcnt;
1057 
1058 	/*
1059 	 * If ".." must be changed (ie the directory gets a new
1060 	 * parent) then the source directory must not be in the
1061 	 * directory heirarchy above the target, as this would
1062 	 * orphan everything below the source directory. Also
1063 	 * the user must have write permission in the source so
1064 	 * as to be able to change "..". We must repeat the call
1065 	 * to namei, as the parent directory is unlocked by the
1066 	 * call to doscheckpath().
1067 	 */
1068 	error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_td);
1069 	VOP_UNLOCK(fvp, 0, td);
1070 	if (VTODE(fdvp)->de_StartCluster != VTODE(tdvp)->de_StartCluster)
1071 		newparent = 1;
1072 
1073 	/*
1074 	 * ok. fvp, fdvp unlocked, tvp, tdvp locked. tvp may be NULL.
1075 	 * DE_RENAME only set if doingdirectory.
1076 	 */
1077 	if (doingdirectory && newparent) {
1078 		if (error)	/* write access check above */
1079 			goto bad;
1080 		if (xp != NULL) {
1081 			vput(tvp);
1082 			xp = NULL;
1083 		}
1084 		/*
1085 		 * checkpath vput's tdvp (VTOI(dp)) on return no matter what,
1086 		 * get an extra ref so we wind up with just an unlocked, ref'd
1087 		 * tdvp.  The 'out' target skips tvp and tdvp cleanups (tdvp
1088 		 * isn't locked so we can't use the out target).
1089 		 */
1090 		vref(tdvp);
1091 		error = doscheckpath(ip, dp);
1092 		tcnp->cn_flags |= CNP_PDIRUNLOCK;
1093 		if (error) {
1094 			vrele(tdvp);
1095 			goto out;
1096 		}
1097 		/*
1098 		 * relookup no longer messes with the ref count.  tdvp must
1099 		 * be unlocked on entry and on success will be locked on
1100 		 * return.
1101 		 */
1102 		error = relookup(tdvp, &tvp, tcnp);
1103 		if (error) {
1104 			if (tcnp->cn_flags & CNP_PDIRUNLOCK)
1105 				vrele(tdvp);
1106 			else
1107 				vput(tdvp);
1108 			goto out;
1109 		}
1110 
1111 		/*
1112 		 * tvp and tdvp are now locked again.
1113 		 */
1114 		dp = VTODE(tdvp);
1115 		xp = tvp ? VTODE(tvp) : NULL;
1116 	}
1117 
1118 	/*
1119 	 * tvp and tdvp are now locked again, the 'bad' target can be used
1120 	 * to clean them up again.  Delete an existant target and clean
1121 	 * up tvp.  Set xp to NULL to indicate that tvp has been cleaned up.
1122 	 */
1123 	if (xp != NULL) {
1124 		/*
1125 		 * Target must be empty if a directory and have no links
1126 		 * to it. Also, ensure source and target are compatible
1127 		 * (both directories, or both not directories).
1128 		 */
1129 		if (xp->de_Attributes & ATTR_DIRECTORY) {
1130 			if (!dosdirempty(xp)) {
1131 				error = ENOTEMPTY;
1132 				goto bad;
1133 			}
1134 			if (!doingdirectory) {
1135 				error = ENOTDIR;
1136 				goto bad;
1137 			}
1138 		} else if (doingdirectory) {
1139 			error = EISDIR;
1140 			goto bad;
1141 		}
1142 		error = removede(dp, xp);
1143 		if (error)
1144 			goto bad;
1145 		vput(tvp);
1146 		xp = NULL;
1147 		tvp = NULL;
1148 	}
1149 
1150 	/*
1151 	 * Convert the filename in tcnp into a dos filename. We copy this
1152 	 * into the denode and directory entry for the destination
1153 	 * file/directory.
1154 	 */
1155 	error = uniqdosname(VTODE(tdvp), tcnp, toname);
1156 	if (error)
1157 		goto bad;
1158 
1159 	/*
1160 	 * Since from wasn't locked at various places above, we have to do
1161 	 * a relookup here.  If the target and source are the same directory
1162 	 * we have to unlock the target directory in order to safely relookup
1163 	 * the source, because relookup expects its directory to be unlocked.
1164 	 *
1165 	 * Note that ap->a_fvp is still valid and ref'd.  Any cleanup must
1166 	 * now take that into account.
1167 	 *
1168 	 * The tdvp locking issues make this a real mess.
1169 	 */
1170 	fcnp->cn_flags &= ~CNP_MODMASK;
1171 	fcnp->cn_flags |= CNP_LOCKPARENT;
1172 	if (newparent == 0)
1173 		VOP_UNLOCK(tdvp, 0, td);
1174 	error = relookup(fdvp, &fvp, fcnp);
1175 	if (error || fvp == NULL) {
1176 		/*
1177 		 * From name has disappeared.  Note: fdvp might == tdvp.
1178 		 *
1179 		 * DE_RENAME is only set if doingdirectory.
1180 		 */
1181 		if (doingdirectory)
1182 			panic("rename: lost dir entry");
1183 		if (fcnp->cn_flags & CNP_PDIRUNLOCK)
1184 			vrele(fdvp);
1185 		else
1186 			vput(fdvp);
1187 		if (newparent == 0)
1188 			vrele(tdvp);
1189 		else
1190 			vput(tdvp);
1191 		vrele(ap->a_fvp);
1192 		return(0);
1193 	}
1194 
1195 	/*
1196 	 * No error occured.  tdvp, fdvp and fvp are all locked.  If
1197 	 * newparent was 0 be aware that fdvp == tdvp.  tvp has been cleaned
1198 	 * up.  ap->a_fvp is still refd.
1199 	 */
1200 	xp = VTODE(fvp);
1201 	zp = VTODE(fdvp);
1202 	from_diroffset = zp->de_fndoffset;
1203 
1204 	/*
1205 	 * Ensure that the directory entry still exists and has not
1206 	 * changed till now. If the source is a file the entry may
1207 	 * have been unlinked or renamed. In either case there is
1208 	 * no further work to be done. If the source is a directory
1209 	 * then it cannot have been rmdir'ed or renamed; this is
1210 	 * prohibited by the DE_RENAME flag.
1211 	 *
1212 	 * DE_RENAME is only set if doingdirectory.
1213 	 */
1214 	if (xp != ip) {
1215 		if (doingdirectory)
1216 			panic("rename: lost dir entry");
1217 		goto done;
1218 	} else {
1219 		u_long new_dirclust;
1220 		u_long new_diroffset;
1221 
1222 		/*
1223 		 * First write a new entry in the destination
1224 		 * directory and mark the entry in the source directory
1225 		 * as deleted.  Then move the denode to the correct hash
1226 		 * chain for its new location in the filesystem.  And, if
1227 		 * we moved a directory, then update its .. entry to point
1228 		 * to the new parent directory.
1229 		 */
1230 		bcopy(ip->de_Name, oldname, 11);
1231 		bcopy(toname, ip->de_Name, 11);	/* update denode */
1232 		dp->de_fndoffset = to_diroffset;
1233 		dp->de_fndcnt = to_count;
1234 		error = createde(ip, dp, (struct denode **)0, tcnp);
1235 		if (error) {
1236 			bcopy(oldname, ip->de_Name, 11);
1237 			goto done;
1238 		}
1239 		ip->de_refcnt++;
1240 		zp->de_fndoffset = from_diroffset;
1241 		error = removede(zp, ip);
1242 		if (error) {
1243 			/* XXX should really panic here, fs is corrupt */
1244 			goto done;
1245 		}
1246 		if (!doingdirectory) {
1247 			error = pcbmap(dp, de_cluster(pmp, to_diroffset), 0,
1248 				       &new_dirclust, 0);
1249 			if (error) {
1250 				/* XXX should really panic here, fs is corrupt */
1251 				goto done;
1252 			}
1253 			if (new_dirclust == MSDOSFSROOT)
1254 				new_diroffset = to_diroffset;
1255 			else
1256 				new_diroffset = to_diroffset & pmp->pm_crbomask;
1257 			msdosfs_reinsert(ip, new_dirclust, new_diroffset);
1258 		}
1259 	}
1260 
1261 	/*
1262 	 * If we moved a directory to a new parent directory, then we must
1263 	 * fixup the ".." entry in the moved directory.
1264 	 */
1265 	if (doingdirectory && newparent) {
1266 		cn = ip->de_StartCluster;
1267 		if (cn == MSDOSFSROOT) {
1268 			/* this should never happen */
1269 			panic("msdosfs_rename(): updating .. in root directory?");
1270 		} else {
1271 			bn = cntobn(pmp, cn);
1272 		}
1273 		error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster, &bp);
1274 		if (error) {
1275 			/* XXX should really panic here, fs is corrupt */
1276 			brelse(bp);
1277 			goto done;
1278 		}
1279 		dotdotp = (struct direntry *)bp->b_data + 1;
1280 		putushort(dotdotp->deStartCluster, dp->de_StartCluster);
1281 		if (FAT32(pmp))
1282 			putushort(dotdotp->deHighClust, dp->de_StartCluster >> 16);
1283 		error = bwrite(bp);
1284 		if (error) {
1285 			/* XXX should really panic here, fs is corrupt */
1286 			goto done;
1287 		}
1288 	}
1289 
1290 	/*
1291 	 * done case fvp, fdvp, tdvp are locked.  ap->a_fvp is refd
1292 	 */
1293 done:
1294 	if (doingdirectory)
1295 		ip->de_flag &= ~DE_RENAME;	/* XXX fvp not locked */
1296 	vput(fvp);
1297 	if (newparent)
1298 		vput(fdvp);
1299 	else
1300 		vrele(fdvp);
1301 	vput(tdvp);
1302 	vrele(ap->a_fvp);
1303 	return (error);
1304 
1305 	/*
1306 	 * 'bad' target: xp governs tvp.  tvp and tdvp arel ocked, fdvp and fvp
1307 	 * are not locked.  ip points to fvp's inode which may have DE_RENAME
1308 	 * set.
1309 	 */
1310 bad:
1311 	if (xp)
1312 		vput(tvp);
1313 	vput(tdvp);
1314 out:
1315 	/*
1316 	 * 'out' target: tvp and tdvp have already been cleaned up.
1317 	 */
1318 	if (doingdirectory)
1319 		ip->de_flag &= ~DE_RENAME;
1320 	vrele(fdvp);
1321 	vrele(fvp);
1322 	return (error);
1323 
1324 }
1325 
1326 static struct {
1327 	struct direntry dot;
1328 	struct direntry dotdot;
1329 } dosdirtemplate = {
1330 	{	".       ", "   ",			/* the . entry */
1331 		ATTR_DIRECTORY,				/* file attribute */
1332 		0,	 				/* reserved */
1333 		0, { 0, 0 }, { 0, 0 },			/* create time & date */
1334 		{ 0, 0 },				/* access date */
1335 		{ 0, 0 },				/* high bits of start cluster */
1336 		{ 210, 4 }, { 210, 4 },			/* modify time & date */
1337 		{ 0, 0 },				/* startcluster */
1338 		{ 0, 0, 0, 0 } 				/* filesize */
1339 	},
1340 	{	"..      ", "   ",			/* the .. entry */
1341 		ATTR_DIRECTORY,				/* file attribute */
1342 		0,	 				/* reserved */
1343 		0, { 0, 0 }, { 0, 0 },			/* create time & date */
1344 		{ 0, 0 },				/* access date */
1345 		{ 0, 0 },				/* high bits of start cluster */
1346 		{ 210, 4 }, { 210, 4 },			/* modify time & date */
1347 		{ 0, 0 },				/* startcluster */
1348 		{ 0, 0, 0, 0 }				/* filesize */
1349 	}
1350 };
1351 
1352 /*
1353  * msdosfs_mkdir(struct vnode *a_dvp, struct vnode **a_vpp,
1354  *		 struct componentname *a_cnp, struct vattr *a_vap)
1355  */
1356 static int
1357 msdosfs_mkdir(struct vop_mkdir_args *ap)
1358 {
1359 	struct componentname *cnp = ap->a_cnp;
1360 	struct denode *dep;
1361 	struct denode *pdep = VTODE(ap->a_dvp);
1362 	struct direntry *denp;
1363 	struct msdosfsmount *pmp = pdep->de_pmp;
1364 	struct buf *bp;
1365 	u_long newcluster, pcl;
1366 	int bn;
1367 	int error;
1368 	struct denode ndirent;
1369 	struct timespec ts;
1370 
1371 	/*
1372 	 * If this is the root directory and there is no space left we
1373 	 * can't do anything.  This is because the root directory can not
1374 	 * change size.
1375 	 */
1376 	if (pdep->de_StartCluster == MSDOSFSROOT
1377 	    && pdep->de_fndoffset >= pdep->de_FileSize) {
1378 		error = ENOSPC;
1379 		goto bad2;
1380 	}
1381 
1382 	/*
1383 	 * Allocate a cluster to hold the about to be created directory.
1384 	 */
1385 	error = clusteralloc(pmp, 0, 1, CLUST_EOFE, &newcluster, NULL);
1386 	if (error)
1387 		goto bad2;
1388 
1389 	bzero(&ndirent, sizeof(ndirent));
1390 	ndirent.de_pmp = pmp;
1391 	ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
1392 	getnanotime(&ts);
1393 	DETIMES(&ndirent, &ts, &ts, &ts);
1394 
1395 	/*
1396 	 * Now fill the cluster with the "." and ".." entries. And write
1397 	 * the cluster to disk.  This way it is there for the parent
1398 	 * directory to be pointing at if there were a crash.
1399 	 */
1400 	bn = cntobn(pmp, newcluster);
1401 	/* always succeeds */
1402 	bp = getblk(pmp->pm_devvp, bn, pmp->pm_bpcluster, 0, 0);
1403 	bzero(bp->b_data, pmp->pm_bpcluster);
1404 	bcopy(&dosdirtemplate, bp->b_data, sizeof dosdirtemplate);
1405 	denp = (struct direntry *)bp->b_data;
1406 	putushort(denp[0].deStartCluster, newcluster);
1407 	putushort(denp[0].deCDate, ndirent.de_CDate);
1408 	putushort(denp[0].deCTime, ndirent.de_CTime);
1409 	denp[0].deCHundredth = ndirent.de_CHun;
1410 	putushort(denp[0].deADate, ndirent.de_ADate);
1411 	putushort(denp[0].deMDate, ndirent.de_MDate);
1412 	putushort(denp[0].deMTime, ndirent.de_MTime);
1413 	pcl = pdep->de_StartCluster;
1414 	if (FAT32(pmp) && pcl == pmp->pm_rootdirblk)
1415 		pcl = 0;
1416 	putushort(denp[1].deStartCluster, pcl);
1417 	putushort(denp[1].deCDate, ndirent.de_CDate);
1418 	putushort(denp[1].deCTime, ndirent.de_CTime);
1419 	denp[1].deCHundredth = ndirent.de_CHun;
1420 	putushort(denp[1].deADate, ndirent.de_ADate);
1421 	putushort(denp[1].deMDate, ndirent.de_MDate);
1422 	putushort(denp[1].deMTime, ndirent.de_MTime);
1423 	if (FAT32(pmp)) {
1424 		putushort(denp[0].deHighClust, newcluster >> 16);
1425 		putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16);
1426 	}
1427 
1428 	error = bwrite(bp);
1429 	if (error)
1430 		goto bad;
1431 
1432 	/*
1433 	 * Now build up a directory entry pointing to the newly allocated
1434 	 * cluster.  This will be written to an empty slot in the parent
1435 	 * directory.
1436 	 */
1437 	error = uniqdosname(pdep, cnp, ndirent.de_Name);
1438 	if (error)
1439 		goto bad;
1440 
1441 	ndirent.de_Attributes = ATTR_DIRECTORY;
1442 	ndirent.de_LowerCase = 0;
1443 	ndirent.de_StartCluster = newcluster;
1444 	ndirent.de_FileSize = 0;
1445 	ndirent.de_dev = pdep->de_dev;
1446 	ndirent.de_devvp = pdep->de_devvp;
1447 	error = createde(&ndirent, pdep, &dep, cnp);
1448 	if (error)
1449 		goto bad;
1450 	*ap->a_vpp = DETOV(dep);
1451 	return (0);
1452 
1453 bad:
1454 	clusterfree(pmp, newcluster, NULL);
1455 bad2:
1456 	return (error);
1457 }
1458 
1459 /*
1460  * msdosfs_rmdir(struct vnode *a_dvp, struct vnode *a_vp,
1461  *		 struct componentname *a_cnp)
1462  */
1463 static int
1464 msdosfs_rmdir(struct vop_rmdir_args *ap)
1465 {
1466 	struct vnode *vp = ap->a_vp;
1467 	struct vnode *dvp = ap->a_dvp;
1468 	struct componentname *cnp = ap->a_cnp;
1469 	struct denode *ip, *dp;
1470 	struct thread *td = cnp->cn_td;
1471 	int error;
1472 
1473 	ip = VTODE(vp);
1474 	dp = VTODE(dvp);
1475 
1476 	/*
1477 	 * Verify the directory is empty (and valid).
1478 	 * (Rmdir ".." won't be valid since
1479 	 *  ".." will contain a reference to
1480 	 *  the current directory and thus be
1481 	 *  non-empty.)
1482 	 */
1483 	error = 0;
1484 	if (!dosdirempty(ip) || ip->de_flag & DE_RENAME) {
1485 		error = ENOTEMPTY;
1486 		goto out;
1487 	}
1488 	/*
1489 	 * Delete the entry from the directory.  For dos filesystems this
1490 	 * gets rid of the directory entry on disk, the in memory copy
1491 	 * still exists but the de_refcnt is <= 0.  This prevents it from
1492 	 * being found by deget().  When the vput() on dep is done we give
1493 	 * up access and eventually msdosfs_reclaim() will be called which
1494 	 * will remove it from the denode cache.
1495 	 */
1496 	error = removede(dp, ip);
1497 	if (error)
1498 		goto out;
1499 	/*
1500 	 * This is where we decrement the link count in the parent
1501 	 * directory.  Since dos filesystems don't do this we just purge
1502 	 * the name cache.
1503 	 */
1504 	VOP_UNLOCK(dvp, 0, td);
1505 	/*
1506 	 * Truncate the directory that is being deleted.
1507 	 */
1508 	error = detrunc(ip, (u_long)0, IO_SYNC, td);
1509 
1510 	vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
1511 out:
1512 	return (error);
1513 }
1514 
1515 /*
1516  * DOS filesystems don't know what symlinks are.
1517  *
1518  * msdosfs_symlink(struct vnode *a_dvp, struct vnode **a_vpp,
1519  *		   struct componentname *a_cnp, struct vattr *a_vap,
1520  *		   char *a_target)
1521  */
1522 static int
1523 msdosfs_symlink(struct vop_symlink_args *ap)
1524 {
1525 	return (EOPNOTSUPP);
1526 }
1527 
1528 /*
1529  * msdosfs_readdir(struct vnode *a_vp, struct uio *a_uio,
1530  *		   struct ucred *a_cred, int *a_eofflag, int *a_ncookies,
1531  *		   u_long **a_cookies)
1532  */
1533 static int
1534 msdosfs_readdir(struct vop_readdir_args *ap)
1535 {
1536 	int error = 0;
1537 	int diff;
1538 	long n;
1539 	int blsize;
1540 	long on;
1541 	u_long cn;
1542 	u_long fileno;
1543 	u_long dirsperblk;
1544 	long bias = 0;
1545 	daddr_t bn, lbn;
1546 	struct buf *bp;
1547 	struct denode *dep = VTODE(ap->a_vp);
1548 	struct msdosfsmount *pmp = dep->de_pmp;
1549 	struct direntry *dentp;
1550 	struct dirent dirbuf;
1551 	struct uio *uio = ap->a_uio;
1552 	u_long *cookies = NULL;
1553 	int ncookies = 0;
1554 	off_t offset, off;
1555 	int chksum = -1;
1556 
1557 #ifdef MSDOSFS_DEBUG
1558 	printf("msdosfs_readdir(): vp %p, uio %p, cred %p, eofflagp %p\n",
1559 	    ap->a_vp, uio, ap->a_cred, ap->a_eofflag);
1560 #endif
1561 
1562 	/*
1563 	 * msdosfs_readdir() won't operate properly on regular files since
1564 	 * it does i/o only with the the filesystem vnode, and hence can
1565 	 * retrieve the wrong block from the buffer cache for a plain file.
1566 	 * So, fail attempts to readdir() on a plain file.
1567 	 */
1568 	if ((dep->de_Attributes & ATTR_DIRECTORY) == 0)
1569 		return (ENOTDIR);
1570 
1571 	/*
1572 	 * To be safe, initialize dirbuf
1573 	 */
1574 	bzero(dirbuf.d_name, sizeof(dirbuf.d_name));
1575 
1576 	/*
1577 	 * If the user buffer is smaller than the size of one dos directory
1578 	 * entry or the file offset is not a multiple of the size of a
1579 	 * directory entry, then we fail the read.
1580 	 */
1581 	off = offset = uio->uio_offset;
1582 	if (uio->uio_resid < sizeof(struct direntry) ||
1583 	    (offset & (sizeof(struct direntry) - 1)))
1584 		return (EINVAL);
1585 
1586 	if (ap->a_ncookies) {
1587 		ncookies = uio->uio_resid / 16;
1588 		MALLOC(cookies, u_long *, ncookies * sizeof(u_long), M_TEMP,
1589 		       M_WAITOK);
1590 		*ap->a_cookies = cookies;
1591 		*ap->a_ncookies = ncookies;
1592 	}
1593 
1594 	dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
1595 
1596 	/*
1597 	 * If they are reading from the root directory then, we simulate
1598 	 * the . and .. entries since these don't exist in the root
1599 	 * directory.  We also set the offset bias to make up for having to
1600 	 * simulate these entries. By this I mean that at file offset 64 we
1601 	 * read the first entry in the root directory that lives on disk.
1602 	 */
1603 	if (dep->de_StartCluster == MSDOSFSROOT
1604 	    || (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)) {
1605 #if 0
1606 		printf("msdosfs_readdir(): going after . or .. in root dir, offset %d\n",
1607 		    offset);
1608 #endif
1609 		bias = 2 * sizeof(struct direntry);
1610 		if (offset < bias) {
1611 			for (n = (int)offset / sizeof(struct direntry);
1612 			     n < 2; n++) {
1613 				if (FAT32(pmp))
1614 					dirbuf.d_fileno = cntobn(pmp,
1615 								 pmp->pm_rootdirblk)
1616 							  * dirsperblk;
1617 				else
1618 					dirbuf.d_fileno = 1;
1619 				dirbuf.d_type = DT_DIR;
1620 				switch (n) {
1621 				case 0:
1622 					dirbuf.d_namlen = 1;
1623 					strcpy(dirbuf.d_name, ".");
1624 					break;
1625 				case 1:
1626 					dirbuf.d_namlen = 2;
1627 					strcpy(dirbuf.d_name, "..");
1628 					break;
1629 				}
1630 				dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
1631 				if (uio->uio_resid < dirbuf.d_reclen)
1632 					goto out;
1633 				error = uiomove((caddr_t) &dirbuf,
1634 						dirbuf.d_reclen, uio);
1635 				if (error)
1636 					goto out;
1637 				offset += sizeof(struct direntry);
1638 				off = offset;
1639 				if (cookies) {
1640 					*cookies++ = offset;
1641 					if (--ncookies <= 0)
1642 						goto out;
1643 				}
1644 			}
1645 		}
1646 	}
1647 
1648 	off = offset;
1649 	while (uio->uio_resid > 0) {
1650 		lbn = de_cluster(pmp, offset - bias);
1651 		on = (offset - bias) & pmp->pm_crbomask;
1652 		n = min(pmp->pm_bpcluster - on, uio->uio_resid);
1653 		diff = dep->de_FileSize - (offset - bias);
1654 		if (diff <= 0)
1655 			break;
1656 		n = min(n, diff);
1657 		error = pcbmap(dep, lbn, &bn, &cn, &blsize);
1658 		if (error)
1659 			break;
1660 		error = bread(pmp->pm_devvp, bn, blsize, &bp);
1661 		if (error) {
1662 			brelse(bp);
1663 			return (error);
1664 		}
1665 		n = min(n, blsize - bp->b_resid);
1666 
1667 		/*
1668 		 * Convert from dos directory entries to fs-independent
1669 		 * directory entries.
1670 		 */
1671 		for (dentp = (struct direntry *)(bp->b_data + on);
1672 		     (char *)dentp < bp->b_data + on + n;
1673 		     dentp++, offset += sizeof(struct direntry)) {
1674 #if 0
1675 			printf("rd: dentp %08x prev %08x crnt %08x deName %02x attr %02x\n",
1676 			    dentp, prev, crnt, dentp->deName[0], dentp->deAttributes);
1677 #endif
1678 			/*
1679 			 * If this is an unused entry, we can stop.
1680 			 */
1681 			if (dentp->deName[0] == SLOT_EMPTY) {
1682 				brelse(bp);
1683 				goto out;
1684 			}
1685 			/*
1686 			 * Skip deleted entries.
1687 			 */
1688 			if (dentp->deName[0] == SLOT_DELETED) {
1689 				chksum = -1;
1690 				continue;
1691 			}
1692 
1693 			/*
1694 			 * Handle Win95 long directory entries
1695 			 */
1696 			if (dentp->deAttributes == ATTR_WIN95) {
1697 				if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
1698 					continue;
1699 				chksum = win2unixfn((struct winentry *)dentp,
1700 					&dirbuf, chksum,
1701 					pmp->pm_flags & MSDOSFSMNT_U2WTABLE,
1702 					pmp->pm_u2w);
1703 				continue;
1704 			}
1705 
1706 			/*
1707 			 * Skip volume labels
1708 			 */
1709 			if (dentp->deAttributes & ATTR_VOLUME) {
1710 				chksum = -1;
1711 				continue;
1712 			}
1713 			/*
1714 			 * This computation of d_fileno must match
1715 			 * the computation of va_fileid in
1716 			 * msdosfs_getattr.
1717 			 */
1718 			if (dentp->deAttributes & ATTR_DIRECTORY) {
1719 				fileno = getushort(dentp->deStartCluster);
1720 				if (FAT32(pmp))
1721 					fileno |= getushort(dentp->deHighClust) << 16;
1722 				/* if this is the root directory */
1723 				if (fileno == MSDOSFSROOT)
1724 					if (FAT32(pmp))
1725 						fileno = cntobn(pmp,
1726 								pmp->pm_rootdirblk)
1727 							 * dirsperblk;
1728 					else
1729 						fileno = 1;
1730 				else
1731 					fileno = cntobn(pmp, fileno) * dirsperblk;
1732 				dirbuf.d_fileno = fileno;
1733 				dirbuf.d_type = DT_DIR;
1734 			} else {
1735 				dirbuf.d_fileno = offset / sizeof(struct direntry);
1736 				dirbuf.d_type = DT_REG;
1737 			}
1738 			if (chksum != winChksum(dentp->deName))
1739 				dirbuf.d_namlen = dos2unixfn(dentp->deName,
1740 				    (u_char *)dirbuf.d_name,
1741 				    dentp->deLowerCase |
1742 					((pmp->pm_flags & MSDOSFSMNT_SHORTNAME) ?
1743 					(LCASE_BASE | LCASE_EXT) : 0),
1744 				    pmp->pm_flags & MSDOSFSMNT_U2WTABLE,
1745 				    pmp->pm_d2u,
1746 				    pmp->pm_flags & MSDOSFSMNT_ULTABLE,
1747 				    pmp->pm_ul);
1748 			else
1749 				dirbuf.d_name[dirbuf.d_namlen] = 0;
1750 			chksum = -1;
1751 			dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
1752 			if (uio->uio_resid < dirbuf.d_reclen) {
1753 				brelse(bp);
1754 				goto out;
1755 			}
1756 			error = uiomove((caddr_t) &dirbuf,
1757 					dirbuf.d_reclen, uio);
1758 			if (error) {
1759 				brelse(bp);
1760 				goto out;
1761 			}
1762 			if (cookies) {
1763 				*cookies++ = offset + sizeof(struct direntry);
1764 				if (--ncookies <= 0) {
1765 					brelse(bp);
1766 					goto out;
1767 				}
1768 			}
1769 			off = offset + sizeof(struct direntry);
1770 		}
1771 		brelse(bp);
1772 	}
1773 out:
1774 	/* Subtract unused cookies */
1775 	if (ap->a_ncookies)
1776 		*ap->a_ncookies -= ncookies;
1777 
1778 	uio->uio_offset = off;
1779 
1780 	/*
1781 	 * Set the eofflag (NFS uses it)
1782 	 */
1783 	if (ap->a_eofflag) {
1784 		if (dep->de_FileSize - (offset - bias) <= 0)
1785 			*ap->a_eofflag = 1;
1786 		else
1787 			*ap->a_eofflag = 0;
1788 	}
1789 	return (error);
1790 }
1791 
1792 /*
1793  * vp  - address of vnode file the file
1794  * bn  - which cluster we are interested in mapping to a filesystem block number.
1795  * vpp - returns the vnode for the block special file holding the filesystem
1796  *	 containing the file of interest
1797  * bnp - address of where to return the filesystem relative block number
1798  *
1799  * msdosfs_bmap(struct vnode *a_vp, daddr_t a_bn, struct vnode **a_vpp,
1800  *		daddr_t *a_bnp, int *a_runp, int *a_runb)
1801  */
1802 static int
1803 msdosfs_bmap(struct vop_bmap_args *ap)
1804 {
1805 	struct denode *dep = VTODE(ap->a_vp);
1806 
1807 	if (ap->a_vpp != NULL)
1808 		*ap->a_vpp = dep->de_devvp;
1809 	if (ap->a_bnp == NULL)
1810 		return (0);
1811 	if (ap->a_runp) {
1812 		/*
1813 		 * Sequential clusters should be counted here.
1814 		 */
1815 		*ap->a_runp = 0;
1816 	}
1817 	if (ap->a_runb) {
1818 		*ap->a_runb = 0;
1819 	}
1820 	return (pcbmap(dep, ap->a_bn, ap->a_bnp, 0, 0));
1821 }
1822 
1823 /*
1824  * msdosfs_strategy(struct vnode *a_vp, struct buf *a_bp)
1825  */
1826 static int
1827 msdosfs_strategy(struct vop_strategy_args *ap)
1828 {
1829 	struct buf *bp = ap->a_bp;
1830 	struct denode *dep = VTODE(bp->b_vp);
1831 	struct vnode *vp;
1832 	int error = 0;
1833 
1834 	if (bp->b_vp->v_type == VBLK || bp->b_vp->v_type == VCHR)
1835 		panic("msdosfs_strategy: spec");
1836 	/*
1837 	 * If we don't already know the filesystem relative block number
1838 	 * then get it using pcbmap().  If pcbmap() returns the block
1839 	 * number as -1 then we've got a hole in the file.  DOS filesystems
1840 	 * don't allow files with holes, so we shouldn't ever see this.
1841 	 */
1842 	if (bp->b_blkno == bp->b_lblkno) {
1843 		error = pcbmap(dep, bp->b_lblkno, &bp->b_blkno, 0, 0);
1844 		if (error) {
1845 			bp->b_error = error;
1846 			bp->b_flags |= B_ERROR;
1847 			biodone(bp);
1848 			return (error);
1849 		}
1850 		if ((long)bp->b_blkno == -1)
1851 			vfs_bio_clrbuf(bp);
1852 	}
1853 	if (bp->b_blkno == -1) {
1854 		biodone(bp);
1855 		return (0);
1856 	}
1857 	/*
1858 	 * Read/write the block from/to the disk that contains the desired
1859 	 * file block.
1860 	 */
1861 	vp = dep->de_devvp;
1862 	bp->b_dev = vp->v_rdev;
1863 	VOP_STRATEGY(vp, bp);
1864 	return (0);
1865 }
1866 
1867 /*
1868  * msdosfs_print(struct vnode *vp)
1869  */
1870 static int
1871 msdosfs_print(struct vop_print_args *ap)
1872 {
1873 	struct denode *dep = VTODE(ap->a_vp);
1874 
1875 	printf(
1876 	    "tag VT_MSDOSFS, startcluster %lu, dircluster %lu, diroffset %lu ",
1877 	       dep->de_StartCluster, dep->de_dirclust, dep->de_diroffset);
1878 	printf(" dev %d, %d", major(dep->de_dev), minor(dep->de_dev));
1879 	lockmgr_printinfo(&ap->a_vp->v_lock);
1880 	printf("\n");
1881 	return (0);
1882 }
1883 
1884 /*
1885  * msdosfs_pathconf(struct vnode *a_vp, int a_name, int *a_retval)
1886  */
1887 static int
1888 msdosfs_pathconf(struct vop_pathconf_args *ap)
1889 {
1890 	struct msdosfsmount *pmp = VTODE(ap->a_vp)->de_pmp;
1891 
1892 	switch (ap->a_name) {
1893 	case _PC_LINK_MAX:
1894 		*ap->a_retval = 1;
1895 		return (0);
1896 	case _PC_NAME_MAX:
1897 		*ap->a_retval = pmp->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12;
1898 		return (0);
1899 	case _PC_PATH_MAX:
1900 		*ap->a_retval = PATH_MAX;
1901 		return (0);
1902 	case _PC_CHOWN_RESTRICTED:
1903 		*ap->a_retval = 1;
1904 		return (0);
1905 	case _PC_NO_TRUNC:
1906 		*ap->a_retval = 0;
1907 		return (0);
1908 	default:
1909 		return (EINVAL);
1910 	}
1911 	/* NOTREACHED */
1912 }
1913 
1914 /*
1915  * get page routine
1916  *
1917  * XXX By default, wimp out... note that a_offset is ignored (and always
1918  * XXX has been).
1919  */
1920 int
1921 msdosfs_getpages(struct vop_getpages_args *ap)
1922 {
1923 	return vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
1924 		ap->a_reqpage);
1925 }
1926 
1927 /*
1928  * put page routine
1929  *
1930  * XXX By default, wimp out... note that a_offset is ignored (and always
1931  * XXX has been).
1932  */
1933 int
1934 msdosfs_putpages(struct vop_putpages_args *ap)
1935 {
1936 	return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
1937 		ap->a_sync, ap->a_rtvals);
1938 }
1939 
1940 /* Global vfs data structures for msdosfs */
1941 struct vnodeopv_entry_desc msdosfs_vnodeop_entries[] = {
1942 	{ &vop_default_desc,		vop_defaultop },
1943 	{ &vop_access_desc,		(vnodeopv_entry_t) msdosfs_access },
1944 	{ &vop_bmap_desc,		(vnodeopv_entry_t) msdosfs_bmap },
1945 	{ &vop_lookup_desc,		(vnodeopv_entry_t) msdosfs_lookup },
1946 	{ &vop_close_desc,		(vnodeopv_entry_t) msdosfs_close },
1947 	{ &vop_create_desc,		(vnodeopv_entry_t) msdosfs_create },
1948 	{ &vop_fsync_desc,		(vnodeopv_entry_t) msdosfs_fsync },
1949 	{ &vop_getattr_desc,		(vnodeopv_entry_t) msdosfs_getattr },
1950 	{ &vop_inactive_desc,		(vnodeopv_entry_t) msdosfs_inactive },
1951 	{ &vop_islocked_desc,		(vnodeopv_entry_t) vop_stdislocked },
1952 	{ &vop_link_desc,		(vnodeopv_entry_t) msdosfs_link },
1953 	{ &vop_lock_desc,		(vnodeopv_entry_t) vop_stdlock },
1954 	{ &vop_mkdir_desc,		(vnodeopv_entry_t) msdosfs_mkdir },
1955 	{ &vop_mknod_desc,		(vnodeopv_entry_t) msdosfs_mknod },
1956 	{ &vop_pathconf_desc,		(vnodeopv_entry_t) msdosfs_pathconf },
1957 	{ &vop_print_desc,		(vnodeopv_entry_t) msdosfs_print },
1958 	{ &vop_read_desc,		(vnodeopv_entry_t) msdosfs_read },
1959 	{ &vop_readdir_desc,		(vnodeopv_entry_t) msdosfs_readdir },
1960 	{ &vop_reclaim_desc,		(vnodeopv_entry_t) msdosfs_reclaim },
1961 	{ &vop_remove_desc,		(vnodeopv_entry_t) msdosfs_remove },
1962 	{ &vop_rename_desc,		(vnodeopv_entry_t) msdosfs_rename },
1963 	{ &vop_rmdir_desc,		(vnodeopv_entry_t) msdosfs_rmdir },
1964 	{ &vop_setattr_desc,		(vnodeopv_entry_t) msdosfs_setattr },
1965 	{ &vop_strategy_desc,		(vnodeopv_entry_t) msdosfs_strategy },
1966 	{ &vop_symlink_desc,		(vnodeopv_entry_t) msdosfs_symlink },
1967 	{ &vop_unlock_desc,		(vnodeopv_entry_t) vop_stdunlock },
1968 	{ &vop_write_desc,		(vnodeopv_entry_t) msdosfs_write },
1969 	{ &vop_getpages_desc,		(vnodeopv_entry_t) msdosfs_getpages },
1970 	{ &vop_putpages_desc,		(vnodeopv_entry_t) msdosfs_putpages },
1971 	{ NULL, NULL }
1972 };
1973