xref: /freebsd/sys/fs/msdosfs/msdosfs_vfsops.c (revision 6b3455a7665208c366849f0b2b3bc916fb97516e)
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/iconv.h>
65 #include <sys/mutex.h>
66 
67 #include <fs/msdosfs/bpb.h>
68 #include <fs/msdosfs/bootsect.h>
69 #include <fs/msdosfs/msdosfsmount.h>
70 #include <fs/msdosfs/direntry.h>
71 #include <fs/msdosfs/denode.h>
72 #include <fs/msdosfs/fat.h>
73 
74 #include "opt_msdosfs.h"
75 
76 #define MSDOSFS_DFLTBSIZE       4096
77 
78 #if 1 /*def PC98*/
79 /*
80  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
81  *       garbage or a random value :-{
82  *       If you want to use that broken-signatured media, define the
83  *       following symbol even though PC/AT.
84  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
85  */
86 #define	MSDOSFS_NOCHECKSIG
87 #endif
88 
89 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOSFS mount structure");
90 static MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOSFS file allocation table");
91 
92 struct iconv_functions *msdosfs_iconv = NULL;
93 
94 static int	update_mp(struct mount *mp, struct msdosfs_args *argp,
95 		    struct thread *td);
96 static int	mountmsdosfs(struct vnode *devvp, struct mount *mp,
97 		    struct thread *td, struct msdosfs_args *argp);
98 static vfs_fhtovp_t	msdosfs_fhtovp;
99 static vfs_omount_t	msdosfs_omount;
100 static vfs_root_t	msdosfs_root;
101 static vfs_statfs_t	msdosfs_statfs;
102 static vfs_sync_t	msdosfs_sync;
103 static vfs_unmount_t	msdosfs_unmount;
104 static vfs_vptofh_t	msdosfs_vptofh;
105 
106 static int
107 update_mp(mp, argp, td)
108 	struct mount *mp;
109 	struct msdosfs_args *argp;
110 	struct thread *td;
111 {
112 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
113 	int error;
114 
115 	pmp->pm_gid = argp->gid;
116 	pmp->pm_uid = argp->uid;
117 	pmp->pm_mask = argp->mask & ALLPERMS;
118 	pmp->pm_dirmask = argp->dirmask & ALLPERMS;
119 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
120 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
121 		msdosfs_iconv->open(argp->cs_win, argp->cs_local , &pmp->pm_u2w);
122 		msdosfs_iconv->open(argp->cs_local, argp->cs_win , &pmp->pm_w2u);
123 		msdosfs_iconv->open(argp->cs_dos, argp->cs_local , &pmp->pm_u2d);
124 		msdosfs_iconv->open(argp->cs_local, argp->cs_dos , &pmp->pm_d2u);
125 	} else {
126 		pmp->pm_w2u = NULL;
127 		pmp->pm_u2w = NULL;
128 		pmp->pm_d2u = NULL;
129 		pmp->pm_u2d = NULL;
130 	}
131 
132 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
133 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
134 	else if (!(pmp->pm_flags &
135 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
136 		struct vnode *rootvp;
137 
138 		/*
139 		 * Try to divine whether to support Win'95 long filenames
140 		 */
141 		if (FAT32(pmp))
142 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
143 		else {
144 			if ((error = msdosfs_root(mp, &rootvp, td)) != 0)
145 				return error;
146 			pmp->pm_flags |= findwin95(VTODE(rootvp))
147 				? MSDOSFSMNT_LONGNAME
148 					: MSDOSFSMNT_SHORTNAME;
149 			vput(rootvp);
150 		}
151 	}
152 	return 0;
153 }
154 
155 /*
156  * mp - path - addr in user space of mount point (ie /usr or whatever)
157  * data - addr in user space of mount params including the name of the block
158  * special file to treat as a filesystem.
159  */
160 static int
161 msdosfs_omount(mp, path, data, td)
162 	struct mount *mp;
163 	char *path;
164 	caddr_t data;
165 	struct thread *td;
166 {
167 	struct vnode *devvp;	  /* vnode for blk device to mount */
168 	struct msdosfs_args args; /* will hold data from mount request */
169 	/* msdosfs specific mount control block */
170 	struct msdosfsmount *pmp = NULL;
171 	struct nameidata ndp;
172 	size_t size;
173 	int error, flags;
174 	mode_t accessmode;
175 
176 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
177 	if (error)
178 		return (error);
179 	if (args.magic != MSDOSFS_ARGSMAGIC)
180 		args.flags = 0;
181 	/*
182 	 * If updating, check whether changing from read-only to
183 	 * read/write; if there is no device name, that's all we do.
184 	 */
185 	if (mp->mnt_flag & MNT_UPDATE) {
186 		pmp = VFSTOMSDOSFS(mp);
187 		error = 0;
188 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
189 			flags = WRITECLOSE;
190 			if (mp->mnt_flag & MNT_FORCE)
191 				flags |= FORCECLOSE;
192 			error = vflush(mp, 0, flags, td);
193 		}
194 		if (!error && (mp->mnt_flag & MNT_RELOAD))
195 			/* not yet implemented */
196 			error = EOPNOTSUPP;
197 		if (error)
198 			return (error);
199 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
200 			/*
201 			 * If upgrade to read-write by non-root, then verify
202 			 * that user has necessary permissions on the device.
203 			 */
204 			if (suser(td)) {
205 				devvp = pmp->pm_devvp;
206 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
207 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
208 						   td->td_ucred, td);
209 				if (error) {
210 					VOP_UNLOCK(devvp, 0, td);
211 					return (error);
212 				}
213 				VOP_UNLOCK(devvp, 0, td);
214 			}
215 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
216 
217 			/* Now that the volume is modifiable, mark it dirty. */
218 			error = markvoldirty(pmp, 1);
219 			if (error)
220 				return (error);
221 		}
222 		if (args.fspec == 0) {
223 #ifdef	__notyet__	/* doesn't work correctly with current mountd	XXX */
224 			if (args.flags & MSDOSFSMNT_MNTOPT) {
225 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
226 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
227 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
228 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
229 			}
230 #endif
231 			/*
232 			 * Process export requests.
233 			 */
234 			if ((args.export.ex_flags & MNT_EXPORTED) != 0 &&
235 			    (pmp->pm_flags & MSDOSFS_LARGEFS) != 0)
236 				return (EOPNOTSUPP);
237 			return (vfs_export(mp, &args.export));
238 		}
239 	}
240 	/*
241 	 * Not an update, or updating the name: look up the name
242 	 * and verify that it refers to a sensible disk device.
243 	 */
244 	NDINIT(&ndp, LOOKUP, FOLLOW, UIO_USERSPACE, args.fspec, td);
245 	error = namei(&ndp);
246 	if (error)
247 		return (error);
248 	devvp = ndp.ni_vp;
249 	NDFREE(&ndp, NDF_ONLY_PNBUF);
250 
251 	if (!vn_isdisk(devvp, &error)) {
252 		vrele(devvp);
253 		return (error);
254 	}
255 	/*
256 	 * If mount by non-root, then verify that user has necessary
257 	 * permissions on the device.
258 	 */
259 	if (suser(td)) {
260 		accessmode = VREAD;
261 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
262 			accessmode |= VWRITE;
263 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
264 		error = VOP_ACCESS(devvp, accessmode, td->td_ucred, td);
265 		if (error) {
266 			vput(devvp);
267 			return (error);
268 		}
269 		VOP_UNLOCK(devvp, 0, td);
270 	}
271 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
272 		error = mountmsdosfs(devvp, mp, td, &args);
273 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
274 		pmp = VFSTOMSDOSFS(mp);
275 #endif
276 	} else {
277 		if (devvp != pmp->pm_devvp)
278 			error = EINVAL;	/* XXX needs translation */
279 		else
280 			vrele(devvp);
281 	}
282 	if (error) {
283 		vrele(devvp);
284 		return (error);
285 	}
286 
287 	error = update_mp(mp, &args, td);
288 	if (error) {
289 		msdosfs_unmount(mp, MNT_FORCE, td);
290 		return error;
291 	}
292 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
293 	    &size);
294 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
295 	(void) msdosfs_statfs(mp, &mp->mnt_stat, td);
296 #ifdef MSDOSFS_DEBUG
297 	printf("msdosfs_omount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
298 #endif
299 	return (0);
300 }
301 
302 static int
303 mountmsdosfs(devvp, mp, td, argp)
304 	struct vnode *devvp;
305 	struct mount *mp;
306 	struct thread *td;
307 	struct msdosfs_args *argp;
308 {
309 	struct msdosfsmount *pmp;
310 	struct buf *bp;
311 	struct cdev *dev = devvp->v_rdev;
312 	union bootsector *bsp;
313 	struct byte_bpb33 *b33;
314 	struct byte_bpb50 *b50;
315 	struct byte_bpb710 *b710;
316 	u_int8_t SecPerClust;
317 	u_long clusters;
318 	int	ronly, error;
319 
320 	/*
321 	 * Disallow multiple mounts of the same device.
322 	 * Disallow mounting of a device that is currently in use
323 	 * (except for root, which might share swap device for miniroot).
324 	 * Flush out any old buffers remaining from a previous use.
325 	 */
326 	error = vfs_mountedon(devvp);
327 	if (error)
328 		return (error);
329 	if (vcount(devvp) > 1)
330 		return (EBUSY);
331 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
332 	error = vinvalbuf(devvp, V_SAVE, td->td_ucred, td, 0, 0);
333 	if (error) {
334 		VOP_UNLOCK(devvp, 0, td);
335 		return (error);
336 	}
337 
338 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
339 	/*
340 	 * XXX: open the device with read and write access even if only
341 	 * read access is needed now.  Write access is needed if the
342 	 * filesystem is ever mounted read/write, and we don't change the
343 	 * access mode for remounts.
344 	 */
345 #ifdef notyet
346 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD | FWRITE, FSCRED, td, -1);
347 #else
348 	error = VOP_OPEN(devvp, FREAD | FWRITE, FSCRED, td, -1);
349 #endif
350 	VOP_UNLOCK(devvp, 0, td);
351 	if (error)
352 		return (error);
353 
354 	bp  = NULL; /* both used in error_exit */
355 	pmp = NULL;
356 
357 	/*
358 	 * Read the boot sector of the filesystem, and then check the
359 	 * boot signature.  If not a dos boot sector then error out.
360 	 *
361 	 * NOTE: 2048 is a maximum sector size in current...
362 	 */
363 	error = bread(devvp, 0, 2048, NOCRED, &bp);
364 	if (error)
365 		goto error_exit;
366 	bp->b_flags |= B_AGE;
367 	bsp = (union bootsector *)bp->b_data;
368 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
369 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
370 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
371 
372 #ifndef MSDOSFS_NOCHECKSIG
373 	if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
374 	    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
375 		error = EINVAL;
376 		goto error_exit;
377 	}
378 #endif
379 
380 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
381 	pmp->pm_mountp = mp;
382 
383 	/*
384 	 * Compute several useful quantities from the bpb in the
385 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
386 	 * the fields that are different between dos 5 and dos 3.3.
387 	 */
388 	SecPerClust = b50->bpbSecPerClust;
389 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
390 	if (pmp->pm_BytesPerSec < DEV_BSIZE) {
391 		error = EINVAL;
392 		goto error_exit;
393 	}
394 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
395 	pmp->pm_FATs = b50->bpbFATs;
396 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
397 	pmp->pm_Sectors = getushort(b50->bpbSectors);
398 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
399 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
400 	pmp->pm_Heads = getushort(b50->bpbHeads);
401 	pmp->pm_Media = b50->bpbMedia;
402 
403 	/* calculate the ratio of sector size to DEV_BSIZE */
404 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
405 
406 	/* XXX - We should probably check more values here */
407 	if (!pmp->pm_BytesPerSec || !SecPerClust
408 		|| !pmp->pm_Heads
409 #ifdef PC98
410     		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) {
411 #else
412 		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
413 #endif
414 		error = EINVAL;
415 		goto error_exit;
416 	}
417 
418 	if (pmp->pm_Sectors == 0) {
419 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
420 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
421 	} else {
422 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
423 		pmp->pm_HugeSectors = pmp->pm_Sectors;
424 	}
425 #ifndef MSDOSFS_LARGE
426 	if (pmp->pm_HugeSectors > 0xffffffff /
427 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
428 		/*
429 		 * We cannot deal currently with this size of disk
430 		 * due to fileid limitations (see msdosfs_getattr and
431 		 * msdosfs_readdir)
432 		 */
433 		error = EINVAL;
434 		printf("mountmsdosfs(): disk too big, sorry\n");
435 		goto error_exit;
436 	}
437 #endif	/* !MSDOSFS_LARGE */
438 
439 	if (pmp->pm_RootDirEnts == 0) {
440 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
441 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
442 		    || pmp->pm_Sectors
443 		    || pmp->pm_FATsecs
444 		    || getushort(b710->bpbFSVers)) {
445 			error = EINVAL;
446 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
447 			goto error_exit;
448 		}
449 		pmp->pm_fatmask = FAT32_MASK;
450 		pmp->pm_fatmult = 4;
451 		pmp->pm_fatdiv = 1;
452 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
453 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
454 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
455 		else
456 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
457 	} else
458 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
459 
460 	/*
461 	 * Check a few values (could do some more):
462 	 * - logical sector size: power of 2, >= block size
463 	 * - sectors per cluster: power of 2, >= 1
464 	 * - number of sectors:   >= 1, <= size of partition
465 	 * - number of FAT sectors: >= 1
466 	 */
467 	if ( (SecPerClust == 0)
468 	  || (SecPerClust & (SecPerClust - 1))
469 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
470 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
471 	  || (pmp->pm_HugeSectors == 0)
472 	  || (pmp->pm_FATsecs == 0)
473 	) {
474 		error = EINVAL;
475 		goto error_exit;
476 	}
477 
478 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
479 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
480 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
481 	SecPerClust         *= pmp->pm_BlkPerSec;
482 
483 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
484 
485 	if (FAT32(pmp)) {
486 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
487 		pmp->pm_firstcluster = pmp->pm_fatblk
488 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
489 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
490 	} else {
491 		pmp->pm_rootdirblk = pmp->pm_fatblk +
492 			(pmp->pm_FATs * pmp->pm_FATsecs);
493 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
494 				       + DEV_BSIZE - 1)
495 			/ DEV_BSIZE; /* in blocks */
496 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
497 	}
498 
499 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
500 	    SecPerClust + 1;
501 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
502 
503 	if (pmp->pm_fatmask == 0) {
504 		if (pmp->pm_maxcluster
505 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
506 			/*
507 			 * This will usually be a floppy disk. This size makes
508 			 * sure that one fat entry will not be split across
509 			 * multiple blocks.
510 			 */
511 			pmp->pm_fatmask = FAT12_MASK;
512 			pmp->pm_fatmult = 3;
513 			pmp->pm_fatdiv = 2;
514 		} else {
515 			pmp->pm_fatmask = FAT16_MASK;
516 			pmp->pm_fatmult = 2;
517 			pmp->pm_fatdiv = 1;
518 		}
519 	}
520 
521 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
522 	if (pmp->pm_maxcluster >= clusters) {
523 		printf("Warning: number of clusters (%ld) exceeds FAT "
524 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
525 		pmp->pm_maxcluster = clusters - 1;
526 	}
527 
528 
529 	if (FAT12(pmp))
530 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
531 	else
532 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
533 
534 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
535 	pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
536 
537 	/*
538 	 * Compute mask and shift value for isolating cluster relative byte
539 	 * offsets and cluster numbers from a file offset.
540 	 */
541 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
542 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
543 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
544 
545 	/*
546 	 * Check for valid cluster size
547 	 * must be a power of 2
548 	 */
549 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
550 		error = EINVAL;
551 		goto error_exit;
552 	}
553 
554 	/*
555 	 * Release the bootsector buffer.
556 	 */
557 	brelse(bp);
558 	bp = NULL;
559 
560 	/*
561 	 * Check FSInfo.
562 	 */
563 	if (pmp->pm_fsinfo) {
564 		struct fsinfo *fp;
565 
566 		if ((error = bread(devvp, pmp->pm_fsinfo, fsi_size(pmp),
567 		    NOCRED, &bp)) != 0)
568 			goto error_exit;
569 		fp = (struct fsinfo *)bp->b_data;
570 		if (!bcmp(fp->fsisig1, "RRaA", 4)
571 		    && !bcmp(fp->fsisig2, "rrAa", 4)
572 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
573 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4)) {
574 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
575 			if (pmp->pm_nxtfree == 0xffffffff)
576 				pmp->pm_nxtfree = CLUST_FIRST;
577 		} else
578 			pmp->pm_fsinfo = 0;
579 		brelse(bp);
580 		bp = NULL;
581 	}
582 
583 	/*
584 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
585 	 */
586 	if (pmp->pm_fsinfo && pmp->pm_nxtfree > pmp->pm_maxcluster) {
587 		printf(
588 		"Next free cluster in FSInfo (%lu) exceeds maxcluster (%lu)\n",
589 		    pmp->pm_nxtfree, pmp->pm_maxcluster);
590 		error = EINVAL;
591 		goto error_exit;
592 	}
593 
594 	/*
595 	 * Allocate memory for the bitmap of allocated clusters, and then
596 	 * fill it in.
597 	 */
598 	pmp->pm_inusemap = malloc(howmany(pmp->pm_maxcluster + 1, N_INUSEBITS)
599 				  * sizeof(*pmp->pm_inusemap),
600 				  M_MSDOSFSFAT, M_WAITOK);
601 
602 	/*
603 	 * fillinusemap() needs pm_devvp.
604 	 */
605 	pmp->pm_dev = dev;
606 	pmp->pm_devvp = devvp;
607 
608 	/*
609 	 * Have the inuse map filled in.
610 	 */
611 	if ((error = fillinusemap(pmp)) != 0)
612 		goto error_exit;
613 
614 	/*
615 	 * If they want fat updates to be synchronous then let them suffer
616 	 * the performance degradation in exchange for the on disk copy of
617 	 * the fat being correct just about all the time.  I suppose this
618 	 * would be a good thing to turn on if the kernel is still flakey.
619 	 */
620 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
621 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
622 
623 	/*
624 	 * Finish up.
625 	 */
626 	if (ronly)
627 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
628 	else {
629 		/* Mark the volume dirty while it is mounted read/write. */
630 		if ((error = markvoldirty(pmp, 1)) != 0)
631 			goto error_exit;
632 		pmp->pm_fmod = 1;
633 	}
634 	mp->mnt_data = (qaddr_t) pmp;
635 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
636 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
637 	mp->mnt_flag |= MNT_LOCAL;
638 	devvp->v_rdev->si_mountpoint = mp;
639 
640 #ifdef MSDOSFS_LARGE
641 	msdosfs_fileno_init(mp);
642 #endif
643 
644 	return 0;
645 
646 error_exit:
647 	if (bp)
648 		brelse(bp);
649 	/* XXX: see comment above VOP_OPEN. */
650 #ifdef notyet
651 	(void)VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE, NOCRED, td);
652 #else
653 	(void)VOP_CLOSE(devvp, FREAD | FWRITE, NOCRED, td);
654 #endif
655 	if (pmp) {
656 		if (pmp->pm_inusemap)
657 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
658 		free(pmp, M_MSDOSFSMNT);
659 		mp->mnt_data = (qaddr_t)0;
660 	}
661 	return (error);
662 }
663 
664 /*
665  * Unmount the filesystem described by mp.
666  */
667 static int
668 msdosfs_unmount(mp, mntflags, td)
669 	struct mount *mp;
670 	int mntflags;
671 	struct thread *td;
672 {
673 	struct msdosfsmount *pmp;
674 	int error, flags;
675 
676 	flags = 0;
677 	if (mntflags & MNT_FORCE)
678 		flags |= FORCECLOSE;
679 	error = vflush(mp, 0, flags, td);
680 	if (error)
681 		return error;
682 	pmp = VFSTOMSDOSFS(mp);
683 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
684 		if (pmp->pm_w2u)
685 			msdosfs_iconv->close(pmp->pm_w2u);
686 		if (pmp->pm_u2w)
687 			msdosfs_iconv->close(pmp->pm_u2w);
688 		if (pmp->pm_d2u)
689 			msdosfs_iconv->close(pmp->pm_d2u);
690 		if (pmp->pm_u2d)
691 			msdosfs_iconv->close(pmp->pm_u2d);
692 	}
693 	pmp->pm_devvp->v_rdev->si_mountpoint = NULL;
694 
695 	/* If the volume was mounted read/write, mark it clean now. */
696 	if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) {
697 		error = markvoldirty(pmp, 0);
698 		if (error && (flags & FORCECLOSE) == 0)
699 			return (error);
700 	}
701 #ifdef MSDOSFS_DEBUG
702 	{
703 		struct vnode *vp = pmp->pm_devvp;
704 
705 		VI_LOCK(vp);
706 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
707 		printf("iflag %08lx, usecount %d, writecount %d, holdcnt %ld\n",
708 		    vp->vi_flag, vp->v_usecount, vp->v_writecount,
709 		    vp->v_holdcnt);
710 		printf("id %lu, mount %p, op %p\n",
711 		    vp->v_id, vp->v_mount, vp->v_op);
712 		printf("freef %p, freeb %p, mount %p\n",
713 		    TAILQ_NEXT(vp, v_freelist), vp->v_freelist.tqe_prev,
714 		    vp->v_mount);
715 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
716 		    TAILQ_FIRST(&vp->v_cleanblkhd),
717 		    TAILQ_FIRST(&vp->v_dirtyblkhd),
718 		    vp->v_numoutput, vp->v_type);
719 		printf("union %p, tag %s, data[0] %08x, data[1] %08x\n",
720 		    vp->v_socket, vp->v_tag,
721 		    ((u_int *)vp->v_data)[0],
722 		    ((u_int *)vp->v_data)[1]);
723 		VI_UNLOCK(vp);
724 	}
725 #endif
726 	/* XXX: see comment above VOP_OPEN. */
727 #ifdef notyet
728 	error = VOP_CLOSE(pmp->pm_devvp,
729 	    (pmp->pm_flags & MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE,
730 	    NOCRED, td);
731 #else
732 	error = VOP_CLOSE(pmp->pm_devvp, FREAD | FWRITE, NOCRED, td);
733 #endif
734 	vrele(pmp->pm_devvp);
735 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
736 #ifdef MSDOSFS_LARGE
737 	msdosfs_fileno_free(mp);
738 #endif
739 	free(pmp, M_MSDOSFSMNT);
740 	mp->mnt_data = (qaddr_t)0;
741 	mp->mnt_flag &= ~MNT_LOCAL;
742 	return (error);
743 }
744 
745 static int
746 msdosfs_root(mp, vpp, td)
747 	struct mount *mp;
748 	struct vnode **vpp;
749 	struct thread *td;
750 {
751 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
752 	struct denode *ndep;
753 	int error;
754 
755 #ifdef MSDOSFS_DEBUG
756 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
757 #endif
758 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
759 	if (error)
760 		return (error);
761 	*vpp = DETOV(ndep);
762 	return (0);
763 }
764 
765 static int
766 msdosfs_statfs(mp, sbp, td)
767 	struct mount *mp;
768 	struct statfs *sbp;
769 	struct thread *td;
770 {
771 	struct msdosfsmount *pmp;
772 
773 	pmp = VFSTOMSDOSFS(mp);
774 	sbp->f_bsize = pmp->pm_bpcluster;
775 	sbp->f_iosize = pmp->pm_bpcluster;
776 	sbp->f_blocks = pmp->pm_maxcluster + 1;
777 	sbp->f_bfree = pmp->pm_freeclustercount;
778 	sbp->f_bavail = pmp->pm_freeclustercount;
779 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
780 	sbp->f_ffree = 0;	/* what to put in here? */
781 	if (sbp != &mp->mnt_stat) {
782 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
783 		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
784 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
785 	}
786 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
787 	return (0);
788 }
789 
790 static int
791 msdosfs_sync(mp, waitfor, cred, td)
792 	struct mount *mp;
793 	int waitfor;
794 	struct ucred *cred;
795 	struct thread *td;
796 {
797 	struct vnode *vp, *nvp;
798 	struct denode *dep;
799 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
800 	int error, allerror = 0;
801 
802 	/*
803 	 * If we ever switch to not updating all of the fats all the time,
804 	 * this would be the place to update them from the first one.
805 	 */
806 	if (pmp->pm_fmod != 0) {
807 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
808 			panic("msdosfs_sync: rofs mod");
809 		else {
810 			/* update fats here */
811 		}
812 	}
813 	/*
814 	 * Write back each (modified) denode.
815 	 */
816 	MNT_ILOCK(mp);
817 loop:
818 	MNT_VNODE_FOREACH(vp, mp, nvp) {
819 		VI_LOCK(vp);
820 		if (vp->v_iflag & VI_XLOCK) {
821 			VI_UNLOCK(vp);
822 			continue;
823 		}
824 		MNT_IUNLOCK(mp);
825 		dep = VTODE(vp);
826 		if (vp->v_type == VNON ||
827 		    ((dep->de_flag &
828 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
829 		    (TAILQ_EMPTY(&vp->v_dirtyblkhd) || waitfor == MNT_LAZY))) {
830 			VI_UNLOCK(vp);
831 			MNT_ILOCK(mp);
832 			continue;
833 		}
834 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, td);
835 		if (error) {
836 			MNT_ILOCK(mp);
837 			if (error == ENOENT)
838 				goto loop;
839 			continue;
840 		}
841 		error = VOP_FSYNC(vp, cred, waitfor, td);
842 		if (error)
843 			allerror = error;
844 		VOP_UNLOCK(vp, 0, td);
845 		vrele(vp);
846 		MNT_ILOCK(mp);
847 	}
848 	MNT_IUNLOCK(mp);
849 
850 	/*
851 	 * Flush filesystem control info.
852 	 */
853 	if (waitfor != MNT_LAZY) {
854 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY, td);
855 		error = VOP_FSYNC(pmp->pm_devvp, cred, waitfor, td);
856 		if (error)
857 			allerror = error;
858 		VOP_UNLOCK(pmp->pm_devvp, 0, td);
859 	}
860 	return (allerror);
861 }
862 
863 static int
864 msdosfs_fhtovp(mp, fhp, vpp)
865 	struct mount *mp;
866 	struct fid *fhp;
867 	struct vnode **vpp;
868 {
869 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
870 	struct defid *defhp = (struct defid *) fhp;
871 	struct denode *dep;
872 	int error;
873 
874 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
875 	if (error) {
876 		*vpp = NULLVP;
877 		return (error);
878 	}
879 	*vpp = DETOV(dep);
880 	return (0);
881 }
882 
883 static int
884 msdosfs_vptofh(vp, fhp)
885 	struct vnode *vp;
886 	struct fid *fhp;
887 {
888 	struct denode *dep;
889 	struct defid *defhp;
890 
891 	dep = VTODE(vp);
892 	defhp = (struct defid *)fhp;
893 	defhp->defid_len = sizeof(struct defid);
894 	defhp->defid_dirclust = dep->de_dirclust;
895 	defhp->defid_dirofs = dep->de_diroffset;
896 	/* defhp->defid_gen = dep->de_gen; */
897 	return (0);
898 }
899 
900 static struct vfsops msdosfs_vfsops = {
901 	.vfs_fhtovp =		msdosfs_fhtovp,
902 	.vfs_init =		msdosfs_init,
903 	.vfs_omount =		msdosfs_omount,
904 	.vfs_root =		msdosfs_root,
905 	.vfs_statfs =		msdosfs_statfs,
906 	.vfs_sync =		msdosfs_sync,
907 	.vfs_uninit =		msdosfs_uninit,
908 	.vfs_unmount =		msdosfs_unmount,
909 	.vfs_vptofh =		msdosfs_vptofh,
910 };
911 
912 VFS_SET(msdosfs_vfsops, msdosfs, 0);
913 MODULE_VERSION(msdosfs, 1);
914