xref: /freebsd/sys/fs/msdosfs/msdosfs_vfsops.c (revision 5521ff5a4d1929056e7ffc982fac3341ca54df7c)
1 /* $FreeBSD$ */
2 /*	$NetBSD: msdosfs_vfsops.c,v 1.51 1997/11/17 15:36:58 ws Exp $	*/
3 
4 /*-
5  * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
6  * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
7  * All rights reserved.
8  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by TooLs GmbH.
21  * 4. The name of TooLs GmbH may not be used to endorse or promote products
22  *    derived from this software without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
30  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
31  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
32  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
33  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 /*
36  * Written by Paul Popelka (paulp@uts.amdahl.com)
37  *
38  * You can do anything you want with this software, just don't say you wrote
39  * it, and don't remove this notice.
40  *
41  * This software is provided "as is".
42  *
43  * The author supplies this software to be publicly redistributed on the
44  * understanding that the author is not responsible for the correct
45  * functioning of this software in any circumstances and is not liable for
46  * any damages caused by this software.
47  *
48  * October 1992
49  */
50 
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/conf.h>
54 #include <sys/namei.h>
55 #include <sys/proc.h>
56 #include <sys/kernel.h>
57 #include <sys/vnode.h>
58 #include <sys/mount.h>
59 #include <sys/bio.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 <sys/mutex.h>
65 
66 #include <fs/msdosfs/bpb.h>
67 #include <fs/msdosfs/bootsect.h>
68 #include <fs/msdosfs/direntry.h>
69 #include <fs/msdosfs/denode.h>
70 #include <fs/msdosfs/msdosfsmount.h>
71 #include <fs/msdosfs/fat.h>
72 
73 #define MSDOSFS_DFLTBSIZE       4096
74 
75 #if 1 /*def PC98*/
76 /*
77  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
78  *       garbage or a random value :-{
79  *       If you want to use that broken-signatured media, define the
80  *       following symbol even though PC/AT.
81  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
82  */
83 #define	MSDOSFS_NOCHECKSIG
84 #endif
85 
86 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOSFS mount structure");
87 static MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOSFS file allocation table");
88 
89 static int	update_mp __P((struct mount *mp, struct msdosfs_args *argp));
90 static int	mountmsdosfs __P((struct vnode *devvp, struct mount *mp,
91 				  struct proc *p, struct msdosfs_args *argp));
92 static int	msdosfs_fhtovp __P((struct mount *, struct fid *,
93 				    struct vnode **));
94 static int	msdosfs_mount __P((struct mount *, char *, caddr_t,
95 				   struct nameidata *, struct proc *));
96 static int	msdosfs_root __P((struct mount *, struct vnode **));
97 static int	msdosfs_statfs __P((struct mount *, struct statfs *,
98 				    struct proc *));
99 static int	msdosfs_sync __P((struct mount *, int, struct ucred *,
100 				  struct proc *));
101 static int	msdosfs_unmount __P((struct mount *, int, struct proc *));
102 static int	msdosfs_vptofh __P((struct vnode *, struct fid *));
103 
104 static int
105 update_mp(mp, argp)
106 	struct mount *mp;
107 	struct msdosfs_args *argp;
108 {
109 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
110 	int error;
111 
112 	pmp->pm_gid = argp->gid;
113 	pmp->pm_uid = argp->uid;
114 	pmp->pm_mask = argp->mask & ALLPERMS;
115 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
116 	if (pmp->pm_flags & MSDOSFSMNT_U2WTABLE) {
117 		bcopy(argp->u2w, pmp->pm_u2w, sizeof(pmp->pm_u2w));
118 		bcopy(argp->d2u, pmp->pm_d2u, sizeof(pmp->pm_d2u));
119 		bcopy(argp->u2d, pmp->pm_u2d, sizeof(pmp->pm_u2d));
120 	}
121 	if (pmp->pm_flags & MSDOSFSMNT_ULTABLE) {
122 		bcopy(argp->ul, pmp->pm_ul, sizeof(pmp->pm_ul));
123 		bcopy(argp->lu, pmp->pm_lu, sizeof(pmp->pm_lu));
124 	}
125 
126 #ifndef __FreeBSD__
127 	/*
128 	 * GEMDOS knows nothing (yet) about win95
129 	 */
130 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
131 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
132 #endif
133 
134 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
135 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
136 	else if (!(pmp->pm_flags &
137 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
138 		struct vnode *rootvp;
139 
140 		/*
141 		 * Try to divine whether to support Win'95 long filenames
142 		 */
143 		if (FAT32(pmp))
144 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
145 		else {
146 			if ((error = msdosfs_root(mp, &rootvp)) != 0)
147 				return error;
148 			pmp->pm_flags |= findwin95(VTODE(rootvp))
149 				? MSDOSFSMNT_LONGNAME
150 					: MSDOSFSMNT_SHORTNAME;
151 			vput(rootvp);
152 		}
153 	}
154 	return 0;
155 }
156 
157 #ifndef __FreeBSD__
158 int
159 msdosfs_mountroot()
160 {
161 	register struct mount *mp;
162 	struct proc *p = curproc;	/* XXX */
163 	size_t size;
164 	int error;
165 	struct msdosfs_args args;
166 
167 	if (root_device->dv_class != DV_DISK)
168 		return (ENODEV);
169 
170 	/*
171 	 * Get vnodes for swapdev and rootdev.
172 	 */
173 	if (bdevvp(rootdev, &rootvp))
174 		panic("msdosfs_mountroot: can't setup rootvp");
175 
176 	mp = malloc((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK | M_ZERO);
177 	mp->mnt_op = &msdosfs_vfsops;
178 	mp->mnt_flag = 0;
179 	LIST_INIT(&mp->mnt_vnodelist);
180 
181 	args.flags = 0;
182 	args.uid = 0;
183 	args.gid = 0;
184 	args.mask = 0777;
185 
186 	if ((error = mountmsdosfs(rootvp, mp, p, &args)) != 0) {
187 		free(mp, M_MOUNT);
188 		return (error);
189 	}
190 
191 	if ((error = update_mp(mp, &args)) != 0) {
192 		(void)msdosfs_unmount(mp, 0, p);
193 		free(mp, M_MOUNT);
194 		return (error);
195 	}
196 
197 	if ((error = vfs_lock(mp)) != 0) {
198 		(void)msdosfs_unmount(mp, 0, p);
199 		free(mp, M_MOUNT);
200 		return (error);
201 	}
202 
203 	TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
204 	mp->mnt_vnodecovered = NULLVP;
205 	(void) copystr("/", mp->mnt_stat.f_mntonname, MNAMELEN - 1,
206 	    &size);
207 	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
208 	(void) copystr(ROOTNAME, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
209 	    &size);
210 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
211 	(void)msdosfs_statfs(mp, &mp->mnt_stat, p);
212 	vfs_unlock(mp);
213 	return (0);
214 }
215 #endif
216 
217 /*
218  * mp - path - addr in user space of mount point (ie /usr or whatever)
219  * data - addr in user space of mount params including the name of the block
220  * special file to treat as a filesystem.
221  */
222 static int
223 msdosfs_mount(mp, path, data, ndp, p)
224 	struct mount *mp;
225 	char *path;
226 	caddr_t data;
227 	struct nameidata *ndp;
228 	struct proc *p;
229 {
230 	struct vnode *devvp;	  /* vnode for blk device to mount */
231 	struct msdosfs_args args; /* will hold data from mount request */
232 	/* msdosfs specific mount control block */
233 	struct msdosfsmount *pmp = NULL;
234 	size_t size;
235 	int error, flags;
236 	mode_t accessmode;
237 
238 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
239 	if (error)
240 		return (error);
241 	if (args.magic != MSDOSFS_ARGSMAGIC)
242 		args.flags = 0;
243 	/*
244 	 * If updating, check whether changing from read-only to
245 	 * read/write; if there is no device name, that's all we do.
246 	 */
247 	if (mp->mnt_flag & MNT_UPDATE) {
248 		pmp = VFSTOMSDOSFS(mp);
249 		error = 0;
250 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
251 			flags = WRITECLOSE;
252 			if (mp->mnt_flag & MNT_FORCE)
253 				flags |= FORCECLOSE;
254 			error = vflush(mp, 0, flags);
255 		}
256 		if (!error && (mp->mnt_flag & MNT_RELOAD))
257 			/* not yet implemented */
258 			error = EOPNOTSUPP;
259 		if (error)
260 			return (error);
261 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
262 			/*
263 			 * If upgrade to read-write by non-root, then verify
264 			 * that user has necessary permissions on the device.
265 			 */
266 			if (p->p_ucred->cr_uid != 0) {
267 				devvp = pmp->pm_devvp;
268 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
269 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
270 						   p->p_ucred, p);
271 				if (error) {
272 					VOP_UNLOCK(devvp, 0, p);
273 					return (error);
274 				}
275 				VOP_UNLOCK(devvp, 0, p);
276 			}
277 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
278 		}
279 		if (args.fspec == 0) {
280 #ifdef	__notyet__		/* doesn't work correctly with current mountd	XXX */
281 			if (args.flags & MSDOSFSMNT_MNTOPT) {
282 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
283 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
284 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
285 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
286 			}
287 #endif
288 			/*
289 			 * Process export requests.
290 			 */
291 			return (vfs_export(mp, &args.export));
292 		}
293 	}
294 	/*
295 	 * Not an update, or updating the name: look up the name
296 	 * and verify that it refers to a sensible block device.
297 	 */
298 	NDINIT(ndp, LOOKUP, FOLLOW, UIO_USERSPACE, args.fspec, p);
299 	error = namei(ndp);
300 	if (error)
301 		return (error);
302 	devvp = ndp->ni_vp;
303 	NDFREE(ndp, NDF_ONLY_PNBUF);
304 
305 	if (!vn_isdisk(devvp, &error)) {
306 		vrele(devvp);
307 		return (error);
308 	}
309 	/*
310 	 * If mount by non-root, then verify that user has necessary
311 	 * permissions on the device.
312 	 */
313 	if (p->p_ucred->cr_uid != 0) {
314 		accessmode = VREAD;
315 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
316 			accessmode |= VWRITE;
317 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
318 		error = VOP_ACCESS(devvp, accessmode, p->p_ucred, p);
319 		if (error) {
320 			vput(devvp);
321 			return (error);
322 		}
323 		VOP_UNLOCK(devvp, 0, p);
324 	}
325 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
326 		error = mountmsdosfs(devvp, mp, p, &args);
327 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
328 		pmp = VFSTOMSDOSFS(mp);
329 #endif
330 	} else {
331 		if (devvp != pmp->pm_devvp)
332 			error = EINVAL;	/* XXX needs translation */
333 		else
334 			vrele(devvp);
335 	}
336 	if (error) {
337 		vrele(devvp);
338 		return (error);
339 	}
340 
341 	error = update_mp(mp, &args);
342 	if (error) {
343 		msdosfs_unmount(mp, MNT_FORCE, p);
344 		return error;
345 	}
346 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
347 	    &size);
348 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
349 	(void) msdosfs_statfs(mp, &mp->mnt_stat, p);
350 #ifdef MSDOSFS_DEBUG
351 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
352 #endif
353 	return (0);
354 }
355 
356 static int
357 mountmsdosfs(devvp, mp, p, argp)
358 	struct vnode *devvp;
359 	struct mount *mp;
360 	struct proc *p;
361 	struct msdosfs_args *argp;
362 {
363 	struct msdosfsmount *pmp;
364 	struct buf *bp;
365 	dev_t dev = devvp->v_rdev;
366 #ifndef __FreeBSD__
367 	struct partinfo dpart;
368 	int bsize = 0, dtype = 0, tmp;
369 #endif
370 	union bootsector *bsp;
371 	struct byte_bpb33 *b33;
372 	struct byte_bpb50 *b50;
373 	struct byte_bpb710 *b710;
374 	u_int8_t SecPerClust;
375 	u_long clusters;
376 	int	ronly, error;
377 
378 	/*
379 	 * Disallow multiple mounts of the same device.
380 	 * Disallow mounting of a device that is currently in use
381 	 * (except for root, which might share swap device for miniroot).
382 	 * Flush out any old buffers remaining from a previous use.
383 	 */
384 	error = vfs_mountedon(devvp);
385 	if (error)
386 		return (error);
387 	if (vcount(devvp) > 1 && devvp != rootvp)
388 		return (EBUSY);
389 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
390 	error = vinvalbuf(devvp, V_SAVE, p->p_ucred, p, 0, 0);
391 	VOP_UNLOCK(devvp, 0, p);
392 	if (error)
393 		return (error);
394 
395 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
396 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
397 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, p);
398 	VOP_UNLOCK(devvp, 0, p);
399 	if (error)
400 		return (error);
401 
402 	bp  = NULL; /* both used in error_exit */
403 	pmp = NULL;
404 
405 #ifndef __FreeBSD__
406 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
407 		/*
408 	 	 * We need the disklabel to calculate the size of a FAT entry
409 		 * later on. Also make sure the partition contains a filesystem
410 		 * of type FS_MSDOS. This doesn't work for floppies, so we have
411 		 * to check for them too.
412 	 	 *
413 	 	 * At least some parts of the msdos fs driver seem to assume
414 		 * that the size of a disk block will always be 512 bytes.
415 		 * Let's check it...
416 		 */
417 		error = VOP_IOCTL(devvp, DIOCGPART, (caddr_t)&dpart,
418 				  FREAD, NOCRED, p);
419 		if (error)
420 			goto error_exit;
421 		tmp   = dpart.part->p_fstype;
422 		dtype = dpart.disklab->d_type;
423 		bsize = dpart.disklab->d_secsize;
424 		if (bsize != 512 || (dtype!=DTYPE_FLOPPY && tmp!=FS_MSDOS)) {
425 			error = EINVAL;
426 			goto error_exit;
427 		}
428 	}
429 #endif
430 
431 	/*
432 	 * Read the boot sector of the filesystem, and then check the
433 	 * boot signature.  If not a dos boot sector then error out.
434 	 *
435 	 * NOTE: 2048 is a maximum sector size in current...
436 	 */
437 	error = bread(devvp, 0, 2048, NOCRED, &bp);
438 	if (error)
439 		goto error_exit;
440 	bp->b_flags |= B_AGE;
441 	bsp = (union bootsector *)bp->b_data;
442 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
443 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
444 	b710 = (struct byte_bpb710 *)bsp->bs710.bsPBP;
445 
446 #ifndef __FreeBSD__
447 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
448 #endif
449 #ifndef MSDOSFS_NOCHECKSIG
450 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
451 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
452 			error = EINVAL;
453 			goto error_exit;
454 		}
455 #endif
456 #ifndef __FreeBSD__
457 	}
458 #endif
459 
460 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
461 	pmp->pm_mountp = mp;
462 
463 	/*
464 	 * Compute several useful quantities from the bpb in the
465 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
466 	 * the fields that are different between dos 5 and dos 3.3.
467 	 */
468 	SecPerClust = b50->bpbSecPerClust;
469 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
470 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
471 	pmp->pm_FATs = b50->bpbFATs;
472 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
473 	pmp->pm_Sectors = getushort(b50->bpbSectors);
474 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
475 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
476 	pmp->pm_Heads = getushort(b50->bpbHeads);
477 	pmp->pm_Media = b50->bpbMedia;
478 
479 	/* calculate the ratio of sector size to DEV_BSIZE */
480 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
481 
482 #ifndef __FreeBSD__
483 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
484 #endif
485 		/* XXX - We should probably check more values here */
486 		if (!pmp->pm_BytesPerSec || !SecPerClust
487 			|| !pmp->pm_Heads || pmp->pm_Heads > 255
488 #ifdef PC98
489 	    		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) {
490 #else
491 			|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
492 #endif
493 			error = EINVAL;
494 			goto error_exit;
495 		}
496 #ifndef __FreeBSD__
497 	}
498 #endif
499 
500 	if (pmp->pm_Sectors == 0) {
501 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
502 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
503 	} else {
504 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
505 		pmp->pm_HugeSectors = pmp->pm_Sectors;
506 	}
507 	if (pmp->pm_HugeSectors > 0xffffffff /
508 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
509 		/*
510 		 * We cannot deal currently with this size of disk
511 		 * due to fileid limitations (see msdosfs_getattr and
512 		 * msdosfs_readdir)
513 		 */
514 		error = EINVAL;
515 		printf("mountmsdosfs(): disk too big, sorry\n");
516 		goto error_exit;
517 	}
518 
519 	if (pmp->pm_RootDirEnts == 0) {
520 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
521 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
522 		    || pmp->pm_Sectors
523 		    || pmp->pm_FATsecs
524 		    || getushort(b710->bpbFSVers)) {
525 			error = EINVAL;
526 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
527 			goto error_exit;
528 		}
529 		pmp->pm_fatmask = FAT32_MASK;
530 		pmp->pm_fatmult = 4;
531 		pmp->pm_fatdiv = 1;
532 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
533 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
534 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
535 		else
536 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
537 	} else
538 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
539 
540 	/*
541 	 * Check a few values (could do some more):
542 	 * - logical sector size: power of 2, >= block size
543 	 * - sectors per cluster: power of 2, >= 1
544 	 * - number of sectors:   >= 1, <= size of partition
545 	 */
546 	if ( (SecPerClust == 0)
547 	  || (SecPerClust & (SecPerClust - 1))
548 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
549 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
550 	  || (pmp->pm_HugeSectors == 0)
551 	) {
552 		error = EINVAL;
553 		goto error_exit;
554 	}
555 
556 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
557 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
558 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
559 	SecPerClust         *= pmp->pm_BlkPerSec;
560 
561 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
562 
563 	if (FAT32(pmp)) {
564 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
565 		pmp->pm_firstcluster = pmp->pm_fatblk
566 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
567 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
568 	} else {
569 		pmp->pm_rootdirblk = pmp->pm_fatblk +
570 			(pmp->pm_FATs * pmp->pm_FATsecs);
571 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
572 				       + DEV_BSIZE - 1)
573 			/ DEV_BSIZE; /* in blocks */
574 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
575 	}
576 
577 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
578 	    SecPerClust + 1;
579 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
580 
581 #ifndef __FreeBSD__
582 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
583 		if ((pmp->pm_maxcluster <= (0xff0 - 2))
584 		      && ((dtype == DTYPE_FLOPPY) || ((dtype == DTYPE_VNODE)
585 		      && ((pmp->pm_Heads == 1) || (pmp->pm_Heads == 2))))
586 		    ) {
587 			pmp->pm_fatmask = FAT12_MASK;
588 			pmp->pm_fatmult = 3;
589 			pmp->pm_fatdiv = 2;
590 		} else {
591 			pmp->pm_fatmask = FAT16_MASK;
592 			pmp->pm_fatmult = 2;
593 			pmp->pm_fatdiv = 1;
594 		}
595 	} else
596 #endif
597 	if (pmp->pm_fatmask == 0) {
598 		if (pmp->pm_maxcluster
599 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
600 			/*
601 			 * This will usually be a floppy disk. This size makes
602 			 * sure that one fat entry will not be split across
603 			 * multiple blocks.
604 			 */
605 			pmp->pm_fatmask = FAT12_MASK;
606 			pmp->pm_fatmult = 3;
607 			pmp->pm_fatdiv = 2;
608 		} else {
609 			pmp->pm_fatmask = FAT16_MASK;
610 			pmp->pm_fatmult = 2;
611 			pmp->pm_fatdiv = 1;
612 		}
613 	}
614 
615 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
616 	if (pmp->pm_maxcluster >= clusters) {
617 		printf("Warning: number of clusters (%ld) exceeds FAT "
618 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
619 		pmp->pm_maxcluster = clusters - 1;
620 	}
621 
622 
623 	if (FAT12(pmp))
624 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
625 	else
626 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
627 
628 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
629 	pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
630 
631 	/*
632 	 * Compute mask and shift value for isolating cluster relative byte
633 	 * offsets and cluster numbers from a file offset.
634 	 */
635 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
636 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
637 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
638 
639 	/*
640 	 * Check for valid cluster size
641 	 * must be a power of 2
642 	 */
643 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
644 		error = EINVAL;
645 		goto error_exit;
646 	}
647 
648 	/*
649 	 * Release the bootsector buffer.
650 	 */
651 	brelse(bp);
652 	bp = NULL;
653 
654 	/*
655 	 * Check FSInfo.
656 	 */
657 	if (pmp->pm_fsinfo) {
658 		struct fsinfo *fp;
659 
660 		if ((error = bread(devvp, pmp->pm_fsinfo, fsi_size(pmp),
661 		    NOCRED, &bp)) != 0)
662 			goto error_exit;
663 		fp = (struct fsinfo *)bp->b_data;
664 		if (!bcmp(fp->fsisig1, "RRaA", 4)
665 		    && !bcmp(fp->fsisig2, "rrAa", 4)
666 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
667 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4))
668 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
669 		else
670 			pmp->pm_fsinfo = 0;
671 		brelse(bp);
672 		bp = NULL;
673 	}
674 
675 	/*
676 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?		XXX
677 	 */
678 
679 	/*
680 	 * Allocate memory for the bitmap of allocated clusters, and then
681 	 * fill it in.
682 	 */
683 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
684 				   / N_INUSEBITS)
685 				  * sizeof(*pmp->pm_inusemap),
686 				  M_MSDOSFSFAT, M_WAITOK);
687 
688 	/*
689 	 * fillinusemap() needs pm_devvp.
690 	 */
691 	pmp->pm_dev = dev;
692 	pmp->pm_devvp = devvp;
693 
694 	/*
695 	 * Have the inuse map filled in.
696 	 */
697 	if ((error = fillinusemap(pmp)) != 0)
698 		goto error_exit;
699 
700 	/*
701 	 * If they want fat updates to be synchronous then let them suffer
702 	 * the performance degradation in exchange for the on disk copy of
703 	 * the fat being correct just about all the time.  I suppose this
704 	 * would be a good thing to turn on if the kernel is still flakey.
705 	 */
706 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
707 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
708 
709 	/*
710 	 * Finish up.
711 	 */
712 	if (ronly)
713 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
714 	else
715 		pmp->pm_fmod = 1;
716 	mp->mnt_data = (qaddr_t) pmp;
717 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
718 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
719 	mp->mnt_flag |= MNT_LOCAL;
720 	devvp->v_rdev->si_mountpoint = mp;
721 
722 	return 0;
723 
724 error_exit:
725 	if (bp)
726 		brelse(bp);
727 	(void) VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE, NOCRED, p);
728 	if (pmp) {
729 		if (pmp->pm_inusemap)
730 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
731 		free(pmp, M_MSDOSFSMNT);
732 		mp->mnt_data = (qaddr_t)0;
733 	}
734 	return (error);
735 }
736 
737 /*
738  * Unmount the filesystem described by mp.
739  */
740 static int
741 msdosfs_unmount(mp, mntflags, p)
742 	struct mount *mp;
743 	int mntflags;
744 	struct proc *p;
745 {
746 	struct msdosfsmount *pmp;
747 	int error, flags;
748 
749 	flags = 0;
750 	if (mntflags & MNT_FORCE)
751 		flags |= FORCECLOSE;
752 	error = vflush(mp, 0, flags);
753 	if (error)
754 		return error;
755 	pmp = VFSTOMSDOSFS(mp);
756 	pmp->pm_devvp->v_rdev->si_mountpoint = NULL;
757 #ifdef MSDOSFS_DEBUG
758 	{
759 		struct vnode *vp = pmp->pm_devvp;
760 
761 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
762 		printf("flag %08lx, usecount %d, writecount %d, holdcnt %ld\n",
763 		    vp->v_flag, vp->v_usecount, vp->v_writecount, vp->v_holdcnt);
764 		printf("id %lu, mount %p, op %p\n",
765 		    vp->v_id, vp->v_mount, vp->v_op);
766 		printf("freef %p, freeb %p, mount %p\n",
767 		    TAILQ_NEXT(vp, v_freelist), vp->v_freelist.tqe_prev,
768 		    vp->v_mount);
769 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
770 		    TAILQ_FIRST(&vp->v_cleanblkhd),
771 		    TAILQ_FIRST(&vp->v_dirtyblkhd),
772 		    vp->v_numoutput, vp->v_type);
773 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
774 		    vp->v_socket, vp->v_tag,
775 		    ((u_int *)vp->v_data)[0],
776 		    ((u_int *)vp->v_data)[1]);
777 	}
778 #endif
779 	error = VOP_CLOSE(pmp->pm_devvp,
780 		    (pmp->pm_flags&MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE,
781 		    NOCRED, p);
782 	vrele(pmp->pm_devvp);
783 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
784 	free(pmp, M_MSDOSFSMNT);
785 	mp->mnt_data = (qaddr_t)0;
786 	mp->mnt_flag &= ~MNT_LOCAL;
787 	return (error);
788 }
789 
790 static int
791 msdosfs_root(mp, vpp)
792 	struct mount *mp;
793 	struct vnode **vpp;
794 {
795 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
796 	struct denode *ndep;
797 	int error;
798 
799 #ifdef MSDOSFS_DEBUG
800 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
801 #endif
802 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
803 	if (error)
804 		return (error);
805 	*vpp = DETOV(ndep);
806 	return (0);
807 }
808 
809 static int
810 msdosfs_statfs(mp, sbp, p)
811 	struct mount *mp;
812 	struct statfs *sbp;
813 	struct proc *p;
814 {
815 	struct msdosfsmount *pmp;
816 
817 	pmp = VFSTOMSDOSFS(mp);
818 	sbp->f_bsize = pmp->pm_bpcluster;
819 	sbp->f_iosize = pmp->pm_bpcluster;
820 	sbp->f_blocks = pmp->pm_maxcluster + 1;
821 	sbp->f_bfree = pmp->pm_freeclustercount;
822 	sbp->f_bavail = pmp->pm_freeclustercount;
823 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
824 	sbp->f_ffree = 0;	/* what to put in here? */
825 	if (sbp != &mp->mnt_stat) {
826 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
827 		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
828 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
829 	}
830 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
831 	return (0);
832 }
833 
834 static int
835 msdosfs_sync(mp, waitfor, cred, p)
836 	struct mount *mp;
837 	int waitfor;
838 	struct ucred *cred;
839 	struct proc *p;
840 {
841 	struct vnode *vp, *nvp;
842 	struct denode *dep;
843 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
844 	int error, allerror = 0;
845 
846 	/*
847 	 * If we ever switch to not updating all of the fats all the time,
848 	 * this would be the place to update them from the first one.
849 	 */
850 	if (pmp->pm_fmod != 0) {
851 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
852 			panic("msdosfs_sync: rofs mod");
853 		else {
854 			/* update fats here */
855 		}
856 	}
857 	/*
858 	 * Write back each (modified) denode.
859 	 */
860 	mtx_lock(&mntvnode_mtx);
861 loop:
862 	for (vp = LIST_FIRST(&mp->mnt_vnodelist); vp != NULL; vp = nvp) {
863 		/*
864 		 * If the vnode that we are about to sync is no longer
865 		 * associated with this mount point, start over.
866 		 */
867 		if (vp->v_mount != mp)
868 			goto loop;
869 		nvp = LIST_NEXT(vp, v_mntvnodes);
870 
871 		mtx_unlock(&mntvnode_mtx);
872 		mtx_lock(&vp->v_interlock);
873 		dep = VTODE(vp);
874 		if (vp->v_type == VNON ||
875 		    ((dep->de_flag &
876 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
877 		    (TAILQ_EMPTY(&vp->v_dirtyblkhd) || waitfor == MNT_LAZY))) {
878 			mtx_unlock(&vp->v_interlock);
879 			mtx_lock(&mntvnode_mtx);
880 			continue;
881 		}
882 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, p);
883 		if (error) {
884 			mtx_lock(&mntvnode_mtx);
885 			if (error == ENOENT)
886 				goto loop;
887 			continue;
888 		}
889 		error = VOP_FSYNC(vp, cred, waitfor, p);
890 		if (error)
891 			allerror = error;
892 		VOP_UNLOCK(vp, 0, p);
893 		vrele(vp);
894 		mtx_lock(&mntvnode_mtx);
895 	}
896 	mtx_unlock(&mntvnode_mtx);
897 
898 	/*
899 	 * Flush filesystem control info.
900 	 */
901 	if (waitfor != MNT_LAZY) {
902 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY, p);
903 		error = VOP_FSYNC(pmp->pm_devvp, cred, waitfor, p);
904 		if (error)
905 			allerror = error;
906 		VOP_UNLOCK(pmp->pm_devvp, 0, p);
907 	}
908 	return (allerror);
909 }
910 
911 static int
912 msdosfs_fhtovp(mp, fhp, vpp)
913 	struct mount *mp;
914 	struct fid *fhp;
915 	struct vnode **vpp;
916 {
917 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
918 	struct defid *defhp = (struct defid *) fhp;
919 	struct denode *dep;
920 	int error;
921 
922 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
923 	if (error) {
924 		*vpp = NULLVP;
925 		return (error);
926 	}
927 	*vpp = DETOV(dep);
928 	return (0);
929 }
930 
931 static int
932 msdosfs_vptofh(vp, fhp)
933 	struct vnode *vp;
934 	struct fid *fhp;
935 {
936 	struct denode *dep;
937 	struct defid *defhp;
938 
939 	dep = VTODE(vp);
940 	defhp = (struct defid *)fhp;
941 	defhp->defid_len = sizeof(struct defid);
942 	defhp->defid_dirclust = dep->de_dirclust;
943 	defhp->defid_dirofs = dep->de_diroffset;
944 	/* defhp->defid_gen = dep->de_gen; */
945 	return (0);
946 }
947 
948 static struct vfsops msdosfs_vfsops = {
949 	msdosfs_mount,
950 	vfs_stdstart,
951 	msdosfs_unmount,
952 	msdosfs_root,
953 	vfs_stdquotactl,
954 	msdosfs_statfs,
955 	msdosfs_sync,
956 	vfs_stdvget,
957 	msdosfs_fhtovp,
958 	vfs_stdcheckexp,
959 	msdosfs_vptofh,
960 	msdosfs_init,
961 	msdosfs_uninit,
962 	vfs_stdextattrctl,
963 };
964 
965 VFS_SET(msdosfs_vfsops, msdosfs, 0);
966