xref: /freebsd/sys/fs/msdosfs/msdosfs_vfsops.c (revision 5203edcdc553fda6caa1da8826a89b1a02dad1bf)
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 static int	mountmsdosfs(struct vnode *devvp, struct mount *mp,
96 		    struct thread *td, struct msdosfs_args *argp);
97 static vfs_fhtovp_t	msdosfs_fhtovp;
98 static vfs_mount_t	msdosfs_mount;
99 static vfs_root_t	msdosfs_root;
100 static vfs_statfs_t	msdosfs_statfs;
101 static vfs_sync_t	msdosfs_sync;
102 static vfs_unmount_t	msdosfs_unmount;
103 static vfs_vptofh_t	msdosfs_vptofh;
104 
105 static int
106 update_mp(mp, argp)
107 	struct mount *mp;
108 	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_dirmask = argp->dirmask & ALLPERMS;
117 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
118 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
119 		msdosfs_iconv->open(argp->cs_win, argp->cs_local , &pmp->pm_u2w);
120 		msdosfs_iconv->open(argp->cs_local, argp->cs_win , &pmp->pm_w2u);
121 		msdosfs_iconv->open(argp->cs_dos, argp->cs_local , &pmp->pm_u2d);
122 		msdosfs_iconv->open(argp->cs_local, argp->cs_dos , &pmp->pm_d2u);
123 	} else {
124 		pmp->pm_w2u = NULL;
125 		pmp->pm_u2w = NULL;
126 		pmp->pm_d2u = NULL;
127 		pmp->pm_u2d = NULL;
128 	}
129 
130 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
131 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
132 	else if (!(pmp->pm_flags &
133 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
134 		struct vnode *rootvp;
135 
136 		/*
137 		 * Try to divine whether to support Win'95 long filenames
138 		 */
139 		if (FAT32(pmp))
140 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
141 		else {
142 			if ((error = msdosfs_root(mp, &rootvp)) != 0)
143 				return error;
144 			pmp->pm_flags |= findwin95(VTODE(rootvp))
145 				? MSDOSFSMNT_LONGNAME
146 					: MSDOSFSMNT_SHORTNAME;
147 			vput(rootvp);
148 		}
149 	}
150 	return 0;
151 }
152 
153 /*
154  * mp - path - addr in user space of mount point (ie /usr or whatever)
155  * data - addr in user space of mount params including the name of the block
156  * special file to treat as a filesystem.
157  */
158 static int
159 msdosfs_mount(mp, path, data, ndp, td)
160 	struct mount *mp;
161 	char *path;
162 	caddr_t data;
163 	struct nameidata *ndp;
164 	struct thread *td;
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 
174 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
175 	if (error)
176 		return (error);
177 	if (args.magic != MSDOSFS_ARGSMAGIC)
178 		args.flags = 0;
179 	/*
180 	 * If updating, check whether changing from read-only to
181 	 * read/write; if there is no device name, that's all we do.
182 	 */
183 	if (mp->mnt_flag & MNT_UPDATE) {
184 		pmp = VFSTOMSDOSFS(mp);
185 		error = 0;
186 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
187 			flags = WRITECLOSE;
188 			if (mp->mnt_flag & MNT_FORCE)
189 				flags |= FORCECLOSE;
190 			error = vflush(mp, 0, flags);
191 		}
192 		if (!error && (mp->mnt_flag & MNT_RELOAD))
193 			/* not yet implemented */
194 			error = EOPNOTSUPP;
195 		if (error)
196 			return (error);
197 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
198 			/*
199 			 * If upgrade to read-write by non-root, then verify
200 			 * that user has necessary permissions on the device.
201 			 */
202 			if (suser(td)) {
203 				devvp = pmp->pm_devvp;
204 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
205 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
206 						   td->td_ucred, td);
207 				if (error) {
208 					VOP_UNLOCK(devvp, 0, td);
209 					return (error);
210 				}
211 				VOP_UNLOCK(devvp, 0, td);
212 			}
213 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
214 
215 			/* Now that the volume is modifiable, mark it dirty. */
216 			error = markvoldirty(pmp, 1);
217 			if (error)
218 				return (error);
219 		}
220 		if (args.fspec == 0) {
221 #ifdef	__notyet__	/* doesn't work correctly with current mountd	XXX */
222 			if (args.flags & MSDOSFSMNT_MNTOPT) {
223 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
224 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
225 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
226 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
227 			}
228 #endif
229 			/*
230 			 * Process export requests.
231 			 */
232 			if ((args.export.ex_flags & MNT_EXPORTED) != 0 &&
233 			    (pmp->pm_flags & MSDOSFS_LARGEFS) != 0)
234 				return (EOPNOTSUPP);
235 			return (vfs_export(mp, &args.export));
236 		}
237 	}
238 	/*
239 	 * Not an update, or updating the name: look up the name
240 	 * and verify that it refers to a sensible disk device.
241 	 */
242 	NDINIT(ndp, LOOKUP, FOLLOW, UIO_USERSPACE, args.fspec, td);
243 	error = namei(ndp);
244 	if (error)
245 		return (error);
246 	devvp = ndp->ni_vp;
247 	NDFREE(ndp, NDF_ONLY_PNBUF);
248 
249 	if (!vn_isdisk(devvp, &error)) {
250 		vrele(devvp);
251 		return (error);
252 	}
253 	/*
254 	 * If mount by non-root, then verify that user has necessary
255 	 * permissions on the device.
256 	 */
257 	if (suser(td)) {
258 		accessmode = VREAD;
259 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
260 			accessmode |= VWRITE;
261 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
262 		error = VOP_ACCESS(devvp, accessmode, td->td_ucred, td);
263 		if (error) {
264 			vput(devvp);
265 			return (error);
266 		}
267 		VOP_UNLOCK(devvp, 0, td);
268 	}
269 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
270 		error = mountmsdosfs(devvp, mp, td, &args);
271 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
272 		pmp = VFSTOMSDOSFS(mp);
273 #endif
274 	} else {
275 		if (devvp != pmp->pm_devvp)
276 			error = EINVAL;	/* XXX needs translation */
277 		else
278 			vrele(devvp);
279 	}
280 	if (error) {
281 		vrele(devvp);
282 		return (error);
283 	}
284 
285 	error = update_mp(mp, &args);
286 	if (error) {
287 		msdosfs_unmount(mp, MNT_FORCE, td);
288 		return error;
289 	}
290 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
291 	    &size);
292 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
293 	(void) msdosfs_statfs(mp, &mp->mnt_stat, td);
294 #ifdef MSDOSFS_DEBUG
295 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
296 #endif
297 	return (0);
298 }
299 
300 static int
301 mountmsdosfs(devvp, mp, td, argp)
302 	struct vnode *devvp;
303 	struct mount *mp;
304 	struct thread *td;
305 	struct msdosfs_args *argp;
306 {
307 	struct msdosfsmount *pmp;
308 	struct buf *bp;
309 	struct cdev *dev = devvp->v_rdev;
310 	union bootsector *bsp;
311 	struct byte_bpb33 *b33;
312 	struct byte_bpb50 *b50;
313 	struct byte_bpb710 *b710;
314 	u_int8_t SecPerClust;
315 	u_long clusters;
316 	int	ronly, error;
317 
318 	/*
319 	 * Disallow multiple mounts of the same device.
320 	 * Disallow mounting of a device that is currently in use
321 	 * (except for root, which might share swap device for miniroot).
322 	 * Flush out any old buffers remaining from a previous use.
323 	 */
324 	error = vfs_mountedon(devvp);
325 	if (error)
326 		return (error);
327 	if (vcount(devvp) > 1 && devvp != rootvp)
328 		return (EBUSY);
329 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
330 	error = vinvalbuf(devvp, V_SAVE, td->td_ucred, td, 0, 0);
331 	if (error) {
332 		VOP_UNLOCK(devvp, 0, td);
333 		return (error);
334 	}
335 
336 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
337 	/*
338 	 * XXX: open the device with read and write access even if only
339 	 * read access is needed now.  Write access is needed if the
340 	 * filesystem is ever mounted read/write, and we don't change the
341 	 * access mode for remounts.
342 	 */
343 #ifdef notyet
344 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD | FWRITE, FSCRED, td, -1);
345 #else
346 	error = VOP_OPEN(devvp, FREAD | FWRITE, FSCRED, td, -1);
347 #endif
348 	VOP_UNLOCK(devvp, 0, td);
349 	if (error)
350 		return (error);
351 
352 	bp  = NULL; /* both used in error_exit */
353 	pmp = NULL;
354 
355 	/*
356 	 * Read the boot sector of the filesystem, and then check the
357 	 * boot signature.  If not a dos boot sector then error out.
358 	 *
359 	 * NOTE: 2048 is a maximum sector size in current...
360 	 */
361 	error = bread(devvp, 0, 2048, NOCRED, &bp);
362 	if (error)
363 		goto error_exit;
364 	bp->b_flags |= B_AGE;
365 	bsp = (union bootsector *)bp->b_data;
366 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
367 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
368 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
369 
370 #ifndef MSDOSFS_NOCHECKSIG
371 	if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
372 	    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
373 		error = EINVAL;
374 		goto error_exit;
375 	}
376 #endif
377 
378 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
379 	pmp->pm_mountp = mp;
380 
381 	/*
382 	 * Compute several useful quantities from the bpb in the
383 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
384 	 * the fields that are different between dos 5 and dos 3.3.
385 	 */
386 	SecPerClust = b50->bpbSecPerClust;
387 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
388 	if (pmp->pm_BytesPerSec < DEV_BSIZE) {
389 		error = EINVAL;
390 		goto error_exit;
391 	}
392 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
393 	pmp->pm_FATs = b50->bpbFATs;
394 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
395 	pmp->pm_Sectors = getushort(b50->bpbSectors);
396 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
397 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
398 	pmp->pm_Heads = getushort(b50->bpbHeads);
399 	pmp->pm_Media = b50->bpbMedia;
400 
401 	/* calculate the ratio of sector size to DEV_BSIZE */
402 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
403 
404 	/* XXX - We should probably check more values here */
405 	if (!pmp->pm_BytesPerSec || !SecPerClust
406 		|| !pmp->pm_Heads
407 #ifdef PC98
408     		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) {
409 #else
410 		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
411 #endif
412 		error = EINVAL;
413 		goto error_exit;
414 	}
415 
416 	if (pmp->pm_Sectors == 0) {
417 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
418 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
419 	} else {
420 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
421 		pmp->pm_HugeSectors = pmp->pm_Sectors;
422 	}
423 #ifndef MSDOSFS_LARGE
424 	if (pmp->pm_HugeSectors > 0xffffffff /
425 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
426 		/*
427 		 * We cannot deal currently with this size of disk
428 		 * due to fileid limitations (see msdosfs_getattr and
429 		 * msdosfs_readdir)
430 		 */
431 		error = EINVAL;
432 		printf("mountmsdosfs(): disk too big, sorry\n");
433 		goto error_exit;
434 	}
435 #endif	/* !MSDOSFS_LARGE */
436 
437 	if (pmp->pm_RootDirEnts == 0) {
438 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
439 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
440 		    || pmp->pm_Sectors
441 		    || pmp->pm_FATsecs
442 		    || getushort(b710->bpbFSVers)) {
443 			error = EINVAL;
444 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
445 			goto error_exit;
446 		}
447 		pmp->pm_fatmask = FAT32_MASK;
448 		pmp->pm_fatmult = 4;
449 		pmp->pm_fatdiv = 1;
450 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
451 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
452 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
453 		else
454 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
455 	} else
456 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
457 
458 	/*
459 	 * Check a few values (could do some more):
460 	 * - logical sector size: power of 2, >= block size
461 	 * - sectors per cluster: power of 2, >= 1
462 	 * - number of sectors:   >= 1, <= size of partition
463 	 * - number of FAT sectors: >= 1
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 	  || (pmp->pm_FATsecs == 0)
471 	) {
472 		error = EINVAL;
473 		goto error_exit;
474 	}
475 
476 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
477 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
478 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
479 	SecPerClust         *= pmp->pm_BlkPerSec;
480 
481 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
482 
483 	if (FAT32(pmp)) {
484 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
485 		pmp->pm_firstcluster = pmp->pm_fatblk
486 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
487 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
488 	} else {
489 		pmp->pm_rootdirblk = pmp->pm_fatblk +
490 			(pmp->pm_FATs * pmp->pm_FATsecs);
491 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
492 				       + DEV_BSIZE - 1)
493 			/ DEV_BSIZE; /* in blocks */
494 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
495 	}
496 
497 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
498 	    SecPerClust + 1;
499 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
500 
501 	if (pmp->pm_fatmask == 0) {
502 		if (pmp->pm_maxcluster
503 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
504 			/*
505 			 * This will usually be a floppy disk. This size makes
506 			 * sure that one fat entry will not be split across
507 			 * multiple blocks.
508 			 */
509 			pmp->pm_fatmask = FAT12_MASK;
510 			pmp->pm_fatmult = 3;
511 			pmp->pm_fatdiv = 2;
512 		} else {
513 			pmp->pm_fatmask = FAT16_MASK;
514 			pmp->pm_fatmult = 2;
515 			pmp->pm_fatdiv = 1;
516 		}
517 	}
518 
519 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
520 	if (pmp->pm_maxcluster >= clusters) {
521 		printf("Warning: number of clusters (%ld) exceeds FAT "
522 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
523 		pmp->pm_maxcluster = clusters - 1;
524 	}
525 
526 
527 	if (FAT12(pmp))
528 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
529 	else
530 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
531 
532 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
533 	pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
534 
535 	/*
536 	 * Compute mask and shift value for isolating cluster relative byte
537 	 * offsets and cluster numbers from a file offset.
538 	 */
539 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
540 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
541 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
542 
543 	/*
544 	 * Check for valid cluster size
545 	 * must be a power of 2
546 	 */
547 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
548 		error = EINVAL;
549 		goto error_exit;
550 	}
551 
552 	/*
553 	 * Release the bootsector buffer.
554 	 */
555 	brelse(bp);
556 	bp = NULL;
557 
558 	/*
559 	 * Check FSInfo.
560 	 */
561 	if (pmp->pm_fsinfo) {
562 		struct fsinfo *fp;
563 
564 		if ((error = bread(devvp, pmp->pm_fsinfo, fsi_size(pmp),
565 		    NOCRED, &bp)) != 0)
566 			goto error_exit;
567 		fp = (struct fsinfo *)bp->b_data;
568 		if (!bcmp(fp->fsisig1, "RRaA", 4)
569 		    && !bcmp(fp->fsisig2, "rrAa", 4)
570 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
571 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4)) {
572 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
573 			if (pmp->pm_nxtfree == 0xffffffff)
574 				pmp->pm_nxtfree = CLUST_FIRST;
575 		} else
576 			pmp->pm_fsinfo = 0;
577 		brelse(bp);
578 		bp = NULL;
579 	}
580 
581 	/*
582 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
583 	 */
584 	if (pmp->pm_fsinfo && pmp->pm_nxtfree > pmp->pm_maxcluster) {
585 		printf(
586 		"Next free cluster in FSInfo (%lu) exceeds maxcluster (%lu)\n",
587 		    pmp->pm_nxtfree, pmp->pm_maxcluster);
588 		error = EINVAL;
589 		goto error_exit;
590 	}
591 
592 	/*
593 	 * Allocate memory for the bitmap of allocated clusters, and then
594 	 * fill it in.
595 	 */
596 	pmp->pm_inusemap = malloc(howmany(pmp->pm_maxcluster + 1, N_INUSEBITS)
597 				  * sizeof(*pmp->pm_inusemap),
598 				  M_MSDOSFSFAT, M_WAITOK);
599 
600 	/*
601 	 * fillinusemap() needs pm_devvp.
602 	 */
603 	pmp->pm_dev = dev;
604 	pmp->pm_devvp = devvp;
605 
606 	/*
607 	 * Have the inuse map filled in.
608 	 */
609 	if ((error = fillinusemap(pmp)) != 0)
610 		goto error_exit;
611 
612 	/*
613 	 * If they want fat updates to be synchronous then let them suffer
614 	 * the performance degradation in exchange for the on disk copy of
615 	 * the fat being correct just about all the time.  I suppose this
616 	 * would be a good thing to turn on if the kernel is still flakey.
617 	 */
618 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
619 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
620 
621 	/*
622 	 * Finish up.
623 	 */
624 	if (ronly)
625 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
626 	else {
627 		/* Mark the volume dirty while it is mounted read/write. */
628 		if ((error = markvoldirty(pmp, 1)) != 0)
629 			goto error_exit;
630 		pmp->pm_fmod = 1;
631 	}
632 	mp->mnt_data = (qaddr_t) pmp;
633 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
634 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
635 	mp->mnt_flag |= MNT_LOCAL;
636 	devvp->v_rdev->si_mountpoint = mp;
637 
638 #ifdef MSDOSFS_LARGE
639 	msdosfs_fileno_init(mp);
640 #endif
641 
642 	return 0;
643 
644 error_exit:
645 	if (bp)
646 		brelse(bp);
647 	/* XXX: see comment above VOP_OPEN. */
648 #ifdef notyet
649 	(void)VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE, NOCRED, td);
650 #else
651 	(void)VOP_CLOSE(devvp, FREAD | FWRITE, NOCRED, td);
652 #endif
653 	if (pmp) {
654 		if (pmp->pm_inusemap)
655 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
656 		free(pmp, M_MSDOSFSMNT);
657 		mp->mnt_data = (qaddr_t)0;
658 	}
659 	return (error);
660 }
661 
662 /*
663  * Unmount the filesystem described by mp.
664  */
665 static int
666 msdosfs_unmount(mp, mntflags, td)
667 	struct mount *mp;
668 	int mntflags;
669 	struct thread *td;
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 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
682 		if (pmp->pm_w2u)
683 			msdosfs_iconv->close(pmp->pm_w2u);
684 		if (pmp->pm_u2w)
685 			msdosfs_iconv->close(pmp->pm_u2w);
686 		if (pmp->pm_d2u)
687 			msdosfs_iconv->close(pmp->pm_d2u);
688 		if (pmp->pm_u2d)
689 			msdosfs_iconv->close(pmp->pm_u2d);
690 	}
691 	pmp->pm_devvp->v_rdev->si_mountpoint = NULL;
692 
693 	/* If the volume was mounted read/write, mark it clean now. */
694 	if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) {
695 		error = markvoldirty(pmp, 0);
696 		if (error && (flags & FORCECLOSE) == 0)
697 			return (error);
698 	}
699 #ifdef MSDOSFS_DEBUG
700 	{
701 		struct vnode *vp = pmp->pm_devvp;
702 
703 		VI_LOCK(vp);
704 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
705 		printf("iflag %08lx, usecount %d, writecount %d, holdcnt %ld\n",
706 		    vp->vi_flag, vp->v_usecount, vp->v_writecount,
707 		    vp->v_holdcnt);
708 		printf("id %lu, mount %p, op %p\n",
709 		    vp->v_id, vp->v_mount, vp->v_op);
710 		printf("freef %p, freeb %p, mount %p\n",
711 		    TAILQ_NEXT(vp, v_freelist), vp->v_freelist.tqe_prev,
712 		    vp->v_mount);
713 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
714 		    TAILQ_FIRST(&vp->v_cleanblkhd),
715 		    TAILQ_FIRST(&vp->v_dirtyblkhd),
716 		    vp->v_numoutput, vp->v_type);
717 		printf("union %p, tag %s, data[0] %08x, data[1] %08x\n",
718 		    vp->v_socket, vp->v_tag,
719 		    ((u_int *)vp->v_data)[0],
720 		    ((u_int *)vp->v_data)[1]);
721 		VI_UNLOCK(vp);
722 	}
723 #endif
724 	/* XXX: see comment above VOP_OPEN. */
725 #ifdef notyet
726 	error = VOP_CLOSE(pmp->pm_devvp,
727 	    (pmp->pm_flags & MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE,
728 	    NOCRED, td);
729 #else
730 	error = VOP_CLOSE(pmp->pm_devvp, FREAD | FWRITE, NOCRED, td);
731 #endif
732 	vrele(pmp->pm_devvp);
733 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
734 #ifdef MSDOSFS_LARGE
735 	msdosfs_fileno_free(mp);
736 #endif
737 	free(pmp, M_MSDOSFSMNT);
738 	mp->mnt_data = (qaddr_t)0;
739 	mp->mnt_flag &= ~MNT_LOCAL;
740 	return (error);
741 }
742 
743 static int
744 msdosfs_root(mp, vpp)
745 	struct mount *mp;
746 	struct vnode **vpp;
747 {
748 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
749 	struct denode *ndep;
750 	int error;
751 
752 #ifdef MSDOSFS_DEBUG
753 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
754 #endif
755 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
756 	if (error)
757 		return (error);
758 	*vpp = DETOV(ndep);
759 	return (0);
760 }
761 
762 static int
763 msdosfs_statfs(mp, sbp, td)
764 	struct mount *mp;
765 	struct statfs *sbp;
766 	struct thread *td;
767 {
768 	struct msdosfsmount *pmp;
769 
770 	pmp = VFSTOMSDOSFS(mp);
771 	sbp->f_bsize = pmp->pm_bpcluster;
772 	sbp->f_iosize = pmp->pm_bpcluster;
773 	sbp->f_blocks = pmp->pm_maxcluster + 1;
774 	sbp->f_bfree = pmp->pm_freeclustercount;
775 	sbp->f_bavail = pmp->pm_freeclustercount;
776 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
777 	sbp->f_ffree = 0;	/* what to put in here? */
778 	if (sbp != &mp->mnt_stat) {
779 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
780 		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
781 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
782 	}
783 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
784 	return (0);
785 }
786 
787 static int
788 msdosfs_sync(mp, waitfor, cred, td)
789 	struct mount *mp;
790 	int waitfor;
791 	struct ucred *cred;
792 	struct thread *td;
793 {
794 	struct vnode *vp, *nvp;
795 	struct denode *dep;
796 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
797 	int error, allerror = 0;
798 
799 	/*
800 	 * If we ever switch to not updating all of the fats all the time,
801 	 * this would be the place to update them from the first one.
802 	 */
803 	if (pmp->pm_fmod != 0) {
804 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
805 			panic("msdosfs_sync: rofs mod");
806 		else {
807 			/* update fats here */
808 		}
809 	}
810 	/*
811 	 * Write back each (modified) denode.
812 	 */
813 	MNT_ILOCK(mp);
814 loop:
815 	for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist); vp != NULL; vp = nvp) {
816 		/*
817 		 * If the vnode that we are about to sync is no longer
818 		 * associated with this mount point, start over.
819 		 */
820 		if (vp->v_mount != mp)
821 			goto loop;
822 		nvp = TAILQ_NEXT(vp, v_nmntvnodes);
823 
824 		VI_LOCK(vp);
825 		if (vp->v_iflag & VI_XLOCK) {
826 			VI_UNLOCK(vp);
827 			continue;
828 		}
829 		MNT_IUNLOCK(mp);
830 		dep = VTODE(vp);
831 		if (vp->v_type == VNON ||
832 		    ((dep->de_flag &
833 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
834 		    (TAILQ_EMPTY(&vp->v_dirtyblkhd) || waitfor == MNT_LAZY))) {
835 			VI_UNLOCK(vp);
836 			MNT_ILOCK(mp);
837 			continue;
838 		}
839 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, td);
840 		if (error) {
841 			MNT_ILOCK(mp);
842 			if (error == ENOENT)
843 				goto loop;
844 			continue;
845 		}
846 		error = VOP_FSYNC(vp, cred, waitfor, td);
847 		if (error)
848 			allerror = error;
849 		VOP_UNLOCK(vp, 0, td);
850 		vrele(vp);
851 		MNT_ILOCK(mp);
852 	}
853 	MNT_IUNLOCK(mp);
854 
855 	/*
856 	 * Flush filesystem control info.
857 	 */
858 	if (waitfor != MNT_LAZY) {
859 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY, td);
860 		error = VOP_FSYNC(pmp->pm_devvp, cred, waitfor, td);
861 		if (error)
862 			allerror = error;
863 		VOP_UNLOCK(pmp->pm_devvp, 0, td);
864 	}
865 	return (allerror);
866 }
867 
868 static int
869 msdosfs_fhtovp(mp, fhp, vpp)
870 	struct mount *mp;
871 	struct fid *fhp;
872 	struct vnode **vpp;
873 {
874 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
875 	struct defid *defhp = (struct defid *) fhp;
876 	struct denode *dep;
877 	int error;
878 
879 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
880 	if (error) {
881 		*vpp = NULLVP;
882 		return (error);
883 	}
884 	*vpp = DETOV(dep);
885 	return (0);
886 }
887 
888 static int
889 msdosfs_vptofh(vp, fhp)
890 	struct vnode *vp;
891 	struct fid *fhp;
892 {
893 	struct denode *dep;
894 	struct defid *defhp;
895 
896 	dep = VTODE(vp);
897 	defhp = (struct defid *)fhp;
898 	defhp->defid_len = sizeof(struct defid);
899 	defhp->defid_dirclust = dep->de_dirclust;
900 	defhp->defid_dirofs = dep->de_diroffset;
901 	/* defhp->defid_gen = dep->de_gen; */
902 	return (0);
903 }
904 
905 static struct vfsops msdosfs_vfsops = {
906 	.vfs_fhtovp =		msdosfs_fhtovp,
907 	.vfs_init =		msdosfs_init,
908 	.vfs_mount =		msdosfs_mount,
909 	.vfs_root =		msdosfs_root,
910 	.vfs_statfs =		msdosfs_statfs,
911 	.vfs_sync =		msdosfs_sync,
912 	.vfs_uninit =		msdosfs_uninit,
913 	.vfs_unmount =		msdosfs_unmount,
914 	.vfs_vptofh =		msdosfs_vptofh,
915 };
916 
917 VFS_SET(msdosfs_vfsops, msdosfs, 0);
918 MODULE_VERSION(msdosfs, 1);
919