xref: /dragonfly/sys/vfs/msdosfs/msdosfs_vfsops.c (revision 3f625015)
1 /* $FreeBSD: /usr/local/www/cvsroot/FreeBSD/src/sys/msdosfs/Attic/msdosfs_vfsops.c,v 1.60.2.8 2004/03/02 09:43:04 tjr Exp $ */
2 /* $DragonFly: src/sys/vfs/msdosfs/msdosfs_vfsops.c,v 1.45 2007/05/09 00:53:35 dillon Exp $ */
3 /*	$NetBSD: msdosfs_vfsops.c,v 1.51 1997/11/17 15:36:58 ws 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/conf.h>
55 #include <sys/proc.h>
56 #include <sys/nlookup.h>
57 #include <sys/kernel.h>
58 #include <sys/vnode.h>
59 #include <sys/mount.h>
60 #include <sys/buf.h>
61 #include <sys/fcntl.h>
62 #include <sys/malloc.h>
63 #include <sys/stat.h> 				/* defines ALLPERMS */
64 #include <vm/vm_zone.h>
65 
66 #include "bpb.h"
67 #include "bootsect.h"
68 #include "direntry.h"
69 #include "denode.h"
70 #include "msdosfsmount.h"
71 #include "fat.h"
72 
73 extern struct vop_ops msdosfs_vnode_vops;
74 
75 #define MSDOSFS_DFLTBSIZE       4096
76 
77 #if 1 /*def PC98*/
78 /*
79  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
80  *       garbage or a random value :-{
81  *       If you want to use that broken-signatured media, define the
82  *       following symbol even though PC/AT.
83  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
84  */
85 #define	MSDOSFS_NOCHECKSIG
86 #endif
87 
88 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOSFS mount structure");
89 static MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOSFS file allocation table");
90 
91 static int	update_mp (struct mount *mp, struct msdosfs_args *argp);
92 static int	mountmsdosfs (struct vnode *devvp, struct mount *mp,
93 				  struct msdosfs_args *argp);
94 static int	msdosfs_fhtovp (struct mount *, struct fid *,
95 				    struct vnode **);
96 static int	msdosfs_checkexp (struct mount *, struct sockaddr *,
97 				    int *, struct ucred **);
98 static int	msdosfs_mount (struct mount *, char *, caddr_t,
99 				   struct ucred *);
100 static int	msdosfs_root (struct mount *, struct vnode **);
101 static int	msdosfs_statfs (struct mount *, struct statfs *,
102 				struct ucred *);
103 static int	msdosfs_sync (struct mount *, int);
104 static int	msdosfs_unmount (struct mount *, int);
105 static int	msdosfs_vptofh (struct vnode *, struct fid *);
106 
107 static int
108 update_mp(struct mount *mp, struct msdosfs_args *argp)
109 {
110 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
111 	int error;
112 
113 	pmp->pm_gid = argp->gid;
114 	pmp->pm_uid = argp->uid;
115 	pmp->pm_mask = argp->mask & ALLPERMS;
116 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
117 	if (pmp->pm_flags & MSDOSFSMNT_U2WTABLE) {
118 		bcopy(argp->u2w, pmp->pm_u2w, sizeof(pmp->pm_u2w));
119 		bcopy(argp->d2u, pmp->pm_d2u, sizeof(pmp->pm_d2u));
120 		bcopy(argp->u2d, pmp->pm_u2d, sizeof(pmp->pm_u2d));
121 	}
122 	if (pmp->pm_flags & MSDOSFSMNT_ULTABLE) {
123 		bcopy(argp->ul, pmp->pm_ul, sizeof(pmp->pm_ul));
124 		bcopy(argp->lu, pmp->pm_lu, sizeof(pmp->pm_lu));
125 	}
126 
127 #ifndef __DragonFly__
128 	/*
129 	 * GEMDOS knows nothing (yet) about win95
130 	 */
131 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
132 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
133 #endif
134 
135 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
136 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
137 	else if (!(pmp->pm_flags &
138 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
139 		struct vnode *rootvp;
140 
141 		/*
142 		 * Try to divine whether to support Win'95 long filenames
143 		 */
144 		if (FAT32(pmp))
145 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
146 		else {
147 			if ((error = msdosfs_root(mp, &rootvp)) != 0)
148 				return error;
149 			pmp->pm_flags |= findwin95(VTODE(rootvp))
150 				? MSDOSFSMNT_LONGNAME
151 					: MSDOSFSMNT_SHORTNAME;
152 			vput(rootvp);
153 		}
154 	}
155 	return 0;
156 }
157 
158 /*
159  * mp - path - addr in user space of mount point (ie /usr or whatever)
160  * data - addr in user space of mount params including the name of the block
161  * special file to treat as a filesystem.
162  */
163 static int
164 msdosfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
165 {
166 	struct vnode *devvp;	  /* vnode for blk device to mount */
167 	struct msdosfs_args args; /* will hold data from mount request */
168 	/* msdosfs specific mount control block */
169 	struct msdosfsmount *pmp = NULL;
170 	size_t size;
171 	int error, flags;
172 	mode_t accessmode;
173 	struct nlookupdata nd;
174 
175 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
176 	if (error)
177 		return (error);
178 	if (args.magic != MSDOSFS_ARGSMAGIC)
179 		args.flags = 0;
180 	/*
181 	 * If updating, check whether changing from read-only to
182 	 * read/write; if there is no device name, that's all we do.
183 	 */
184 	if (mp->mnt_flag & MNT_UPDATE) {
185 		pmp = VFSTOMSDOSFS(mp);
186 		error = 0;
187 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
188 			flags = WRITECLOSE;
189 			if (mp->mnt_flag & MNT_FORCE)
190 				flags |= FORCECLOSE;
191 			error = vflush(mp, 0, flags);
192 		}
193 		if (!error && (mp->mnt_flag & MNT_RELOAD))
194 			/* not yet implemented */
195 			error = EOPNOTSUPP;
196 		if (error)
197 			return (error);
198 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
199 			/*
200 			 * If upgrade to read-write by non-root, then verify
201 			 * that user has necessary permissions on the device.
202 			 */
203 			if (cred->cr_uid != 0) {
204 				devvp = pmp->pm_devvp;
205 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
206 				error = VOP_ACCESS(devvp, VREAD | VWRITE, cred);
207 				if (error) {
208 					vn_unlock(devvp);
209 					return (error);
210 				}
211 				vn_unlock(devvp);
212 			}
213 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
214 		}
215 		if (args.fspec == 0) {
216 #ifdef	__notyet__		/* doesn't work correctly with current mountd	XXX */
217 			if (args.flags & MSDOSFSMNT_MNTOPT) {
218 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
219 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
220 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
221 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
222 			}
223 #endif
224 			/*
225 			 * Process export requests.
226 			 */
227 			return (vfs_export(mp, &pmp->pm_export, &args.export));
228 		}
229 	}
230 	/*
231 	 * Not an update, or updating the name: look up the name
232 	 * and verify that it refers to a sensible block device.
233 	 */
234 	devvp = NULL;
235 	error = nlookup_init(&nd, args.fspec, UIO_USERSPACE, NLC_FOLLOW);
236 	if (error == 0)
237 		error = nlookup(&nd);
238 	if (error == 0)
239 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &devvp);
240 	nlookup_done(&nd);
241 	if (error)
242 		return (error);
243 
244 	if (!vn_isdisk(devvp, &error)) {
245 		vrele(devvp);
246 		return (error);
247 	}
248 	/*
249 	 * If mount by non-root, then verify that user has necessary
250 	 * permissions on the device.
251 	 */
252 	if (cred->cr_uid != 0) {
253 		accessmode = VREAD;
254 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
255 			accessmode |= VWRITE;
256 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
257 		error = VOP_ACCESS(devvp, accessmode, cred);
258 		if (error) {
259 			vput(devvp);
260 			return (error);
261 		}
262 		vn_unlock(devvp);
263 	}
264 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
265 		error = mountmsdosfs(devvp, mp, &args);
266 #ifdef MSDOSFS_DEBUG		/* only needed for the kprintf below */
267 		pmp = VFSTOMSDOSFS(mp);
268 #endif
269 	} else {
270 		if (devvp != pmp->pm_devvp)
271 			error = EINVAL;	/* XXX needs translation */
272 		else
273 			vrele(devvp);
274 	}
275 	if (error) {
276 		vrele(devvp);
277 		return (error);
278 	}
279 
280 	error = update_mp(mp, &args);
281 	if (error) {
282 		msdosfs_unmount(mp, MNT_FORCE);
283 		return error;
284 	}
285 
286 	copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &size);
287 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
288 	msdosfs_statfs(mp, &mp->mnt_stat, cred);
289 #ifdef MSDOSFS_DEBUG
290 	kprintf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
291 #endif
292 	return (0);
293 }
294 
295 static int
296 mountmsdosfs(struct vnode *devvp, struct mount *mp, struct msdosfs_args *argp)
297 {
298 	struct msdosfsmount *pmp;
299 	struct buf *bp;
300 	cdev_t dev;
301 #ifndef __DragonFly__
302 	struct partinfo dpart;
303 	int bsize = 0, dtype = 0, tmp;
304 #endif
305 	union bootsector *bsp;
306 	struct byte_bpb33 *b33;
307 	struct byte_bpb50 *b50;
308 	struct byte_bpb710 *b710;
309 	u_int8_t SecPerClust;
310 	u_long clusters;
311 	int	ronly, error;
312 
313 	/*
314 	 * Disallow multiple mounts of the same device.
315 	 * Disallow mounting of a device that is currently in use
316 	 * Flush out any old buffers remaining from a previous use.
317 	 */
318 	error = vfs_mountedon(devvp);
319 	if (error)
320 		return (error);
321 	if (count_udev(devvp->v_umajor, devvp->v_uminor) > 0)
322 		return (EBUSY);
323 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
324 	error = vinvalbuf(devvp, V_SAVE, 0, 0);
325 	vn_unlock(devvp);
326 	if (error)
327 		return (error);
328 
329 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
330 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
331 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, NULL);
332 	vn_unlock(devvp);
333 	if (error)
334 		return (error);
335 	dev = devvp->v_rdev;
336 	bp  = NULL; /* both used in error_exit */
337 	pmp = NULL;
338 
339 #ifndef __DragonFly__
340 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
341 		/*
342 	 	 * We need the disklabel to calculate the size of a FAT entry
343 		 * later on. Also make sure the partition contains a filesystem
344 		 * of type FS_MSDOS. This doesn't work for floppies, so we have
345 		 * to check for them too.
346 	 	 *
347 	 	 * At least some parts of the msdos fs driver seem to assume
348 		 * that the size of a disk block will always be 512 bytes.
349 		 * Let's check it...
350 		 */
351 		error = VOP_IOCTL(devvp, DIOCGPART, (caddr_t)&dpart, FREAD);
352 		if (error)
353 			goto error_exit;
354 		tmp   = dpart.part->p_fstype;
355 		dtype = dpart.disklab->d_type;
356 		bsize = dpart.disklab->d_secsize;
357 		if (bsize != 512 || (dtype!=DTYPE_FLOPPY && tmp!=FS_MSDOS)) {
358 			error = EINVAL;
359 			goto error_exit;
360 		}
361 	}
362 #endif
363 
364 	/*
365 	 * Read the boot sector of the filesystem, and then check the
366 	 * boot signature.  If not a dos boot sector then error out.
367 	 *
368 	 * NOTE: 2048 is a maximum sector size in current...
369 	 */
370 	error = bread(devvp, 0, 2048, &bp);
371 	if (error)
372 		goto error_exit;
373 	bp->b_flags |= B_AGE;
374 	bsp = (union bootsector *)bp->b_data;
375 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
376 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
377 	b710 = (struct byte_bpb710 *)bsp->bs710.bsPBP;
378 
379 #ifndef __DragonFly__
380 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
381 #endif
382 #ifndef MSDOSFS_NOCHECKSIG
383 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
384 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
385 			error = EINVAL;
386 			goto error_exit;
387 		}
388 #endif
389 #ifndef __DragonFly__
390 	}
391 #endif
392 
393 	pmp = kmalloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK);
394 	bzero((caddr_t)pmp, sizeof *pmp);
395 	pmp->pm_mountp = mp;
396 
397 	/*
398 	 * Compute several useful quantities from the bpb in the
399 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
400 	 * the fields that are different between dos 5 and dos 3.3.
401 	 */
402 	SecPerClust = b50->bpbSecPerClust;
403 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
404 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
405 	pmp->pm_FATs = b50->bpbFATs;
406 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
407 	pmp->pm_Sectors = getushort(b50->bpbSectors);
408 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
409 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
410 	pmp->pm_Heads = getushort(b50->bpbHeads);
411 	pmp->pm_Media = b50->bpbMedia;
412 
413 	/* calculate the ratio of sector size to DEV_BSIZE */
414 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
415 
416 #ifndef __DragonFly__
417 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
418 #endif
419 		/* XXX - We should probably check more values here */
420 		if (!pmp->pm_BytesPerSec || !SecPerClust
421 			|| !pmp->pm_Heads
422 			|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
423 			error = EINVAL;
424 			goto error_exit;
425 		}
426 #ifndef __DragonFly__
427 	}
428 #endif
429 
430 	if (pmp->pm_Sectors == 0) {
431 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
432 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
433 	} else {
434 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
435 		pmp->pm_HugeSectors = pmp->pm_Sectors;
436 	}
437 
438 	if (pmp->pm_RootDirEnts == 0) {
439 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
440 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
441 		    || pmp->pm_Sectors
442 		    || pmp->pm_FATsecs
443 		    || getushort(b710->bpbFSVers)) {
444 			error = EINVAL;
445 			kprintf("mountmsdosfs(): bad FAT32 filesystem\n");
446 			goto error_exit;
447 		}
448 		pmp->pm_fatmask = FAT32_MASK;
449 		pmp->pm_fatmult = 4;
450 		pmp->pm_fatdiv = 1;
451 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
452 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
453 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
454 		else
455 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
456 	} else
457 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
458 
459 	/*
460 	 * Check a few values (could do some more):
461 	 * - logical sector size: power of 2, >= block size
462 	 * - sectors per cluster: power of 2, >= 1
463 	 * - number of sectors:   >= 1, <= size of partition
464 	 */
465 	if ( (SecPerClust == 0)
466 	  || (SecPerClust & (SecPerClust - 1))
467 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
468 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
469 	  || (pmp->pm_HugeSectors == 0)
470 	) {
471 		error = EINVAL;
472 		goto error_exit;
473 	}
474 
475 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
476 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
477 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
478 	SecPerClust         *= pmp->pm_BlkPerSec;
479 
480 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
481 
482 	if (FAT32(pmp)) {
483 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
484 		pmp->pm_firstcluster = pmp->pm_fatblk
485 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
486 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
487 	} else {
488 		pmp->pm_rootdirblk = pmp->pm_fatblk +
489 			(pmp->pm_FATs * pmp->pm_FATsecs);
490 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
491 				       + DEV_BSIZE - 1)
492 			/ DEV_BSIZE; /* in blocks */
493 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
494 	}
495 
496 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
497 	    SecPerClust + 1;
498 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
499 
500 #ifndef __DragonFly__
501 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
502 		if ((pmp->pm_maxcluster <= (0xff0 - 2))
503 		      && ((dtype == DTYPE_FLOPPY) || ((dtype == DTYPE_VNODE)
504 		      && ((pmp->pm_Heads == 1) || (pmp->pm_Heads == 2))))
505 		    ) {
506 			pmp->pm_fatmask = FAT12_MASK;
507 			pmp->pm_fatmult = 3;
508 			pmp->pm_fatdiv = 2;
509 		} else {
510 			pmp->pm_fatmask = FAT16_MASK;
511 			pmp->pm_fatmult = 2;
512 			pmp->pm_fatdiv = 1;
513 		}
514 	} else
515 #endif
516 	if (pmp->pm_fatmask == 0) {
517 		if (pmp->pm_maxcluster
518 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
519 			/*
520 			 * This will usually be a floppy disk. This size makes
521 			 * sure that one fat entry will not be split across
522 			 * multiple blocks.
523 			 */
524 			pmp->pm_fatmask = FAT12_MASK;
525 			pmp->pm_fatmult = 3;
526 			pmp->pm_fatdiv = 2;
527 		} else {
528 			pmp->pm_fatmask = FAT16_MASK;
529 			pmp->pm_fatmult = 2;
530 			pmp->pm_fatdiv = 1;
531 		}
532 	}
533 
534 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
535 	if (pmp->pm_maxcluster >= clusters) {
536 		kprintf("Warning: number of clusters (%ld) exceeds FAT "
537 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
538 		pmp->pm_maxcluster = clusters - 1;
539 	}
540 
541 
542 	if (FAT12(pmp))
543 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
544 	else
545 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
546 
547 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
548 	pmp->pm_bnshift = DEV_BSHIFT;
549 
550 	/*
551 	 * Compute mask and shift value for isolating cluster relative byte
552 	 * offsets and cluster numbers from a file offset.
553 	 */
554 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
555 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
556 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
557 
558 	/*
559 	 * Check for valid cluster size
560 	 * must be a power of 2
561 	 */
562 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
563 		error = EINVAL;
564 		goto error_exit;
565 	}
566 
567 	/*
568 	 * Release the bootsector buffer.
569 	 */
570 	brelse(bp);
571 	bp = NULL;
572 
573 	/*
574 	 * Check FSInfo.
575 	 */
576 	if (pmp->pm_fsinfo) {
577 		struct fsinfo *fp;
578 
579 		if ((error = bread(devvp, de_bntodoff(pmp, pmp->pm_fsinfo), fsi_size(pmp), &bp)) != 0)
580 			goto error_exit;
581 		fp = (struct fsinfo *)bp->b_data;
582 		if (!bcmp(fp->fsisig1, "RRaA", 4)
583 		    && !bcmp(fp->fsisig2, "rrAa", 4)
584 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
585 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4)) {
586 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
587 			if (pmp->pm_nxtfree == 0xffffffff)
588 				pmp->pm_nxtfree = CLUST_FIRST;
589 		} else
590 			pmp->pm_fsinfo = 0;
591 		brelse(bp);
592 		bp = NULL;
593 	}
594 
595 	/*
596 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
597 	 */
598 	if (pmp->pm_fsinfo && pmp->pm_nxtfree > pmp->pm_maxcluster) {
599 		kprintf(
600 		"Next free cluster in FSInfo (%lu) exceeds maxcluster (%lu)\n",
601 		    pmp->pm_nxtfree, pmp->pm_maxcluster);
602 		error = EINVAL;
603 		goto error_exit;
604 	}
605 
606 	/*
607 	 * Allocate memory for the bitmap of allocated clusters, and then
608 	 * fill it in.
609 	 */
610 	pmp->pm_inusemap = kmalloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
611 				   / N_INUSEBITS)
612 				  * sizeof(*pmp->pm_inusemap),
613 				  M_MSDOSFSFAT, M_WAITOK);
614 
615 	/*
616 	 * fillinusemap() needs pm_devvp.
617 	 */
618 	pmp->pm_dev = dev;
619 	pmp->pm_devvp = devvp;
620 
621 	/*
622 	 * Have the inuse map filled in.
623 	 */
624 	if ((error = fillinusemap(pmp)) != 0)
625 		goto error_exit;
626 
627 	/*
628 	 * If they want fat updates to be synchronous then let them suffer
629 	 * the performance degradation in exchange for the on disk copy of
630 	 * the fat being correct just about all the time.  I suppose this
631 	 * would be a good thing to turn on if the kernel is still flakey.
632 	 */
633 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
634 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
635 
636 	/*
637 	 * Finish up.
638 	 */
639 	if (ronly)
640 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
641 	else
642 		pmp->pm_fmod = 1;
643 	mp->mnt_data = (qaddr_t) pmp;
644 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
645 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
646 	mp->mnt_flag |= MNT_LOCAL;
647 	vfs_add_vnodeops(mp, &msdosfs_vnode_vops, &mp->mnt_vn_norm_ops);
648 	dev->si_mountpoint = mp;
649 
650 	return 0;
651 
652 error_exit:
653 	if (bp)
654 		brelse(bp);
655 	VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE);
656 	if (pmp) {
657 		if (pmp->pm_inusemap)
658 			kfree(pmp->pm_inusemap, M_MSDOSFSFAT);
659 		kfree(pmp, M_MSDOSFSMNT);
660 		mp->mnt_data = (qaddr_t)0;
661 	}
662 	return (error);
663 }
664 
665 /*
666  * Unmount the filesystem described by mp.
667  */
668 static int
669 msdosfs_unmount(struct mount *mp, int mntflags)
670 {
671 	struct msdosfsmount *pmp;
672 	int error, flags;
673 
674 	flags = 0;
675 	if (mntflags & MNT_FORCE)
676 		flags |= FORCECLOSE;
677 	error = vflush(mp, 0, flags);
678 	if (error)
679 		return error;
680 	pmp = VFSTOMSDOSFS(mp);
681 	pmp->pm_devvp->v_rdev->si_mountpoint = NULL;
682 #ifdef MSDOSFS_DEBUG
683 	{
684 		struct vnode *vp = pmp->pm_devvp;
685 
686 		kprintf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
687 		kprintf("flag %08lx, sysrefs %d, writecount %d, auxrefs %ld\n",
688 		    vp->v_flag, vp->v_sysref.refcnt,
689 		    vp->v_writecount, vp->v_auxrefs);
690 		kprintf("mount %p, op %p\n", vp->v_mount, vp->v_op);
691 		kprintf("freef %p, freeb %p, mount %p\n",
692 		    TAILQ_NEXT(vp, v_freelist), TAILQ_PREV(vp, v_freelist),
693 		    vp->v_mount);
694 		kprintf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
695 		    RB_EMPTY(&vp->v_rbclean_tree),
696 		    RB_EMPTY(&vp->v_rbdirty_tree),
697 		    vp->v_track_write.bk_active, vp->v_type);
698 		kprintf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
699 		    vp->v_socket, vp->v_tag,
700 		    ((u_int *)vp->v_data)[0],
701 		    ((u_int *)vp->v_data)[1]);
702 	}
703 #endif
704 	error = VOP_CLOSE(pmp->pm_devvp,
705 		    (pmp->pm_flags&MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE);
706 	vrele(pmp->pm_devvp);
707 	kfree(pmp->pm_inusemap, M_MSDOSFSFAT);
708 	kfree(pmp, M_MSDOSFSMNT);
709 	mp->mnt_data = (qaddr_t)0;
710 	mp->mnt_flag &= ~MNT_LOCAL;
711 	return (error);
712 }
713 
714 static int
715 msdosfs_root(struct mount *mp, struct vnode **vpp)
716 {
717 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
718 	struct denode *ndep;
719 	int error;
720 
721 #ifdef MSDOSFS_DEBUG
722 	kprintf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
723 #endif
724 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
725 	if (error)
726 		return (error);
727 	*vpp = DETOV(ndep);
728 	return (0);
729 }
730 
731 static int
732 msdosfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
733 {
734 	struct msdosfsmount *pmp;
735 
736 	pmp = VFSTOMSDOSFS(mp);
737 	sbp->f_bsize = pmp->pm_bpcluster;
738 	sbp->f_iosize = pmp->pm_bpcluster;
739 	sbp->f_blocks = pmp->pm_maxcluster + 1;
740 	sbp->f_bfree = pmp->pm_freeclustercount;
741 	sbp->f_bavail = pmp->pm_freeclustercount;
742 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
743 	sbp->f_ffree = 0;	/* what to put in here? */
744 	if (sbp != &mp->mnt_stat) {
745 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
746 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
747 	}
748 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
749 	return (0);
750 }
751 
752 struct scaninfo {
753 	int rescan;
754 	int allerror;
755 	int waitfor;
756 };
757 
758 static int msdosfs_sync_scan(struct mount *mp, struct vnode *vp, void *data);
759 
760 static int
761 msdosfs_sync(struct mount *mp, int waitfor)
762 {
763 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
764 	struct scaninfo scaninfo;
765 	int error;
766 
767 	/*
768 	 * If we ever switch to not updating all of the fats all the time,
769 	 * this would be the place to update them from the first one.
770 	 */
771 	if (pmp->pm_fmod != 0) {
772 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
773 			panic("msdosfs_sync: rofs mod");
774 		else {
775 			/* update fats here */
776 		}
777 	}
778 	/*
779 	 * Write back each (modified) denode.
780 	 */
781 	scaninfo.allerror = 0;
782 	scaninfo.rescan = 1;
783 	while (scaninfo.rescan) {
784 		scaninfo.rescan = 0;
785 		vmntvnodescan(mp, VMSC_GETVP|VMSC_NOWAIT, NULL, msdosfs_sync_scan, &scaninfo);
786 	}
787 
788 	/*
789 	 * Flush filesystem control info.
790 	 */
791 	if (waitfor != MNT_LAZY) {
792 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
793 		if ((error = VOP_FSYNC(pmp->pm_devvp, waitfor)) != 0)
794 			scaninfo.allerror = error;
795 		vn_unlock(pmp->pm_devvp);
796 	}
797 	return (scaninfo.allerror);
798 }
799 
800 static int
801 msdosfs_sync_scan(struct mount *mp, struct vnode *vp, void *data)
802 {
803 	struct scaninfo *info = data;
804 	struct denode *dep;
805 	int error;
806 
807 	dep = VTODE(vp);
808 	if (vp->v_type == VNON ||
809 	    ((dep->de_flag &
810 	    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
811 	    (RB_EMPTY(&vp->v_rbdirty_tree) || info->waitfor == MNT_LAZY))) {
812 		return(0);
813 	}
814 	if ((error = VOP_FSYNC(vp, info->waitfor)) != 0)
815 		info->allerror = error;
816 	return(0);
817 }
818 
819 static int
820 msdosfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
821 {
822 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
823 	struct defid *defhp = (struct defid *) fhp;
824 	struct denode *dep;
825 	int error;
826 
827 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
828 	if (error) {
829 		*vpp = NULLVP;
830 		return (error);
831 	}
832 	*vpp = DETOV(dep);
833 	return (0);
834 }
835 
836 static int
837 msdosfs_checkexp(struct mount *mp, struct sockaddr *nam, int *exflagsp,
838 		 struct ucred **credanonp)
839 {
840 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
841 	struct netcred *np;
842 
843 	np = vfs_export_lookup(mp, &pmp->pm_export, nam);
844 	if (np == NULL)
845 		return (EACCES);
846 	*exflagsp = np->netc_exflags;
847 	*credanonp = &np->netc_anon;
848 	return (0);
849 }
850 
851 static int
852 msdosfs_vptofh(struct vnode *vp, struct fid *fhp)
853 {
854 	struct denode *dep;
855 	struct defid *defhp;
856 
857 	dep = VTODE(vp);
858 	defhp = (struct defid *)fhp;
859 	defhp->defid_len = sizeof(struct defid);
860 	defhp->defid_dirclust = dep->de_dirclust;
861 	defhp->defid_dirofs = dep->de_diroffset;
862 	/* defhp->defid_gen = dep->de_gen; */
863 	return (0);
864 }
865 
866 static struct vfsops msdosfs_vfsops = {
867 	.vfs_mount =     	msdosfs_mount,
868 	.vfs_unmount =   	msdosfs_unmount,
869 	.vfs_root =     	msdosfs_root,
870 	.vfs_statfs =   	msdosfs_statfs,
871 	.vfs_sync =     	msdosfs_sync,
872 	.vfs_fhtovp =   	msdosfs_fhtovp,
873 	.vfs_checkexp =  	msdosfs_checkexp,
874 	.vfs_vptofh =   	msdosfs_vptofh,
875 	.vfs_init =     	msdosfs_init,
876 	.vfs_uninit =   	msdosfs_uninit
877 };
878 
879 VFS_SET(msdosfs_vfsops, msdos, 0);
880