xref: /dragonfly/sys/vfs/msdosfs/msdosfs_vfsops.c (revision 0066c2fb)
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 /*	$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/proc.h>
55 #include <sys/nlookup.h>
56 #include <sys/kernel.h>
57 #include <sys/vnode.h>
58 #include <sys/iconv.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 <sys/buf2.h>
67 
68 #include "bpb.h"
69 #include "bootsect.h"
70 #include "direntry.h"
71 #include "denode.h"
72 #include "msdosfsmount.h"
73 #include "fat.h"
74 
75 extern struct vop_ops msdosfs_vnode_vops;
76 struct iconv_functions *msdos_iconv;
77 
78 #define MSDOSFS_DFLTBSIZE       4096
79 #define ENCODING_UNICODE        "UTF-16BE"
80 #if 1 /*def PC98*/
81 /*
82  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
83  *       garbage or a random value :-{
84  *       If you want to use that broken-signatured media, define the
85  *       following symbol even though PC/AT.
86  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
87  */
88 #define	MSDOSFS_NOCHECKSIG
89 #endif
90 
91 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOSFS mount structure");
92 static MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOSFS file allocation table");
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 msdosfs_args *argp);
97 static int	msdosfs_fhtovp (struct mount *, struct vnode *,
98 				struct fid *, struct vnode **);
99 static int	msdosfs_checkexp (struct mount *, struct sockaddr *,
100 				    int *, struct ucred **);
101 static int	msdosfs_mount (struct mount *, char *, caddr_t,
102 				   struct ucred *);
103 static int	msdosfs_root (struct mount *, struct vnode **);
104 static int	msdosfs_statfs (struct mount *, struct statfs *,
105 				struct ucred *);
106 static int	msdosfs_sync (struct mount *, int);
107 static int	msdosfs_unmount (struct mount *, int);
108 static int	msdosfs_vptofh (struct vnode *, struct fid *);
109 
110 static int
111 update_mp(struct mount *mp, struct msdosfs_args *argp)
112 {
113 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
114 	int error;
115         char cs_local[ICONV_CSNMAXLEN];
116         char cs_dos[ICONV_CSNMAXLEN];
117 
118 	pmp->pm_gid = argp->gid;
119 	pmp->pm_uid = argp->uid;
120 	pmp->pm_mask = argp->mask & ALLPERMS;
121 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
122 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdos_iconv) {
123 		bcopy(argp->cs_local, cs_local, sizeof(cs_local));
124 		bcopy(argp->cs_dos, cs_dos, sizeof(cs_dos));
125 		kprintf("local: %s dos: %s\n",argp->cs_local, argp->cs_dos);
126 		error = msdos_iconv->open(cs_local, ENCODING_UNICODE, &pmp->pm_w2u);
127 		if(error)
128 			return error;
129 		error = msdos_iconv->open(ENCODING_UNICODE, cs_local, &pmp->pm_u2w);
130 		if(error)
131 			return error;
132 		error = msdos_iconv->open(cs_dos, cs_local, &pmp->pm_u2d);
133 		if(error)
134 			return error;
135 		error = msdos_iconv->open(cs_local, cs_dos, &pmp->pm_d2u);
136 		if(error)
137 			return error;
138 	}
139 
140 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
141 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
142 	else if (!(pmp->pm_flags &
143 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
144 		struct vnode *rootvp;
145 
146 		/*
147 		 * Try to divine whether to support Win'95 long filenames
148 		 */
149 		if (FAT32(pmp))
150 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
151 		else {
152 			if ((error = msdosfs_root(mp, &rootvp)) != 0)
153 				return error;
154 			pmp->pm_flags |= findwin95(VTODE(rootvp))
155 				? MSDOSFSMNT_LONGNAME
156 					: MSDOSFSMNT_SHORTNAME;
157 			vput(rootvp);
158 		}
159 	}
160 	return 0;
161 }
162 
163 /*
164  * mp - path - addr in user space of mount point (ie /usr or whatever)
165  * data - addr in user space of mount params including the name of the block
166  * special file to treat as a filesystem.
167  */
168 static int
169 msdosfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
170 {
171 	struct vnode *devvp;	  /* vnode for blk device to mount */
172 	struct msdosfs_args args; /* will hold data from mount request */
173 	/* msdosfs specific mount control block */
174 	struct msdosfsmount *pmp = NULL;
175 	size_t size;
176 	int error, flags;
177 	mode_t accessmode;
178 	struct nlookupdata nd;
179 
180 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
181 	if (error)
182 		return (error);
183 	if (args.magic != MSDOSFS_ARGSMAGIC)
184 		args.flags = 0;
185 	/*
186 	 * If updating, check whether changing from read-only to
187 	 * read/write; if there is no device name, that's all we do.
188 	 */
189 	if (mp->mnt_flag & MNT_UPDATE) {
190 		pmp = VFSTOMSDOSFS(mp);
191 		error = 0;
192 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
193 			flags = WRITECLOSE;
194 			if (mp->mnt_flag & MNT_FORCE)
195 				flags |= FORCECLOSE;
196 			error = vflush(mp, 0, flags);
197 			if (error == 0) {
198 				devvp = pmp->pm_devvp;
199 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
200 				VOP_OPEN(devvp, FREAD, FSCRED, NULL);
201 				VOP_CLOSE(devvp, FREAD|FWRITE, NULL);
202 				vn_unlock(devvp);
203 				pmp->pm_flags |= MSDOSFSMNT_RONLY;
204 			}
205 		}
206 		if (!error && (mp->mnt_flag & MNT_RELOAD))
207 			/* not yet implemented */
208 			error = EOPNOTSUPP;
209 		if (error)
210 			return (error);
211 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
212 			/*
213 			 * If upgrade to read-write by non-root, then verify
214 			 * that user has necessary permissions on the device.
215 			 */
216 			devvp = pmp->pm_devvp;
217 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
218 			if (cred->cr_uid != 0) {
219 				error = VOP_EACCESS(devvp, VREAD | VWRITE, cred);
220 				if (error) {
221 					vn_unlock(devvp);
222 					return (error);
223 				}
224 			}
225 			VOP_OPEN(devvp, FREAD|FWRITE, FSCRED, NULL);
226 			VOP_CLOSE(devvp, FREAD, NULL);
227 			vn_unlock(devvp);
228 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
229 		}
230 		if (args.fspec == NULL) {
231 #ifdef	__notyet__		/* doesn't work correctly with current mountd	XXX */
232 			if (args.flags & MSDOSFSMNT_MNTOPT) {
233 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
234 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
235 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
236 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
237 			}
238 #endif
239 			/*
240 			 * Process export requests.
241 			 */
242 			return (vfs_export(mp, &pmp->pm_export, &args.export));
243 		}
244 	}
245 	/*
246 	 * Not an update, or updating the name: look up the name
247 	 * and verify that it refers to a sensible block device.
248 	 */
249 	devvp = NULL;
250 	error = nlookup_init(&nd, args.fspec, UIO_USERSPACE, NLC_FOLLOW);
251 	if (error == 0)
252 		error = nlookup(&nd);
253 	if (error == 0)
254 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &devvp);
255 	nlookup_done(&nd);
256 	if (error)
257 		return (error);
258 
259 	if (!vn_isdisk(devvp, &error)) {
260 		vrele(devvp);
261 		return (error);
262 	}
263 	/*
264 	 * If mount by non-root, then verify that user has necessary
265 	 * permissions on the device.
266 	 */
267 	if (cred->cr_uid != 0) {
268 		accessmode = VREAD;
269 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
270 			accessmode |= VWRITE;
271 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
272 		error = VOP_EACCESS(devvp, accessmode, cred);
273 		if (error) {
274 			vput(devvp);
275 			return (error);
276 		}
277 		vn_unlock(devvp);
278 	}
279 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
280 		error = mountmsdosfs(devvp, mp, &args);
281 #ifdef MSDOSFS_DEBUG		/* only needed for the kprintf below */
282 		pmp = VFSTOMSDOSFS(mp);
283 #endif
284 	} else {
285 		if (devvp != pmp->pm_devvp)
286 			error = EINVAL;	/* XXX needs translation */
287 		else
288 			vrele(devvp);
289 	}
290 	if (error) {
291 		vrele(devvp);
292 		return (error);
293 	}
294 
295 	error = update_mp(mp, &args);
296 	if (error) {
297 		msdosfs_unmount(mp, MNT_FORCE);
298 		return error;
299 	}
300 
301 	copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &size);
302 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
303 	msdosfs_statfs(mp, &mp->mnt_stat, cred);
304 #ifdef MSDOSFS_DEBUG
305 	kprintf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
306 #endif
307 	return (0);
308 }
309 
310 static int
311 mountmsdosfs(struct vnode *devvp, struct mount *mp, struct msdosfs_args *argp)
312 {
313 	struct msdosfsmount *pmp;
314 	struct buf *bp;
315 	cdev_t dev;
316 	union bootsector *bsp;
317 	struct byte_bpb33 *b33;
318 	struct byte_bpb50 *b50;
319 	struct byte_bpb710 *b710;
320 	u_int8_t SecPerClust;
321 	u_long clusters;
322 	int	ronly, error;
323 
324 	/*
325 	 * Disallow multiple mounts of the same device.
326 	 * Disallow mounting of a device that is currently in use
327 	 * Flush out any old buffers remaining from a previous use.
328 	 */
329 	error = vfs_mountedon(devvp);
330 	if (error)
331 		return (error);
332 	if (vcount(devvp) > 0)
333 		return (EBUSY);
334 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
335 	error = vinvalbuf(devvp, V_SAVE, 0, 0);
336 	vn_unlock(devvp);
337 	if (error)
338 		return (error);
339 
340 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
341 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
342 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, NULL);
343 	vn_unlock(devvp);
344 	if (error)
345 		return (error);
346 	dev = devvp->v_rdev;
347 	bp  = NULL; /* both used in error_exit */
348 	pmp = NULL;
349 
350 	/*
351 	 * Read the boot sector of the filesystem, and then check the
352 	 * boot signature.  If not a dos boot sector then error out.
353 	 *
354 	 * NOTE: 2048 is a maximum sector size in current...
355 	 */
356 	error = bread(devvp, 0, 2048, &bp);
357 	if (error)
358 		goto error_exit;
359 	bp->b_flags |= B_AGE;
360 	bsp = (union bootsector *)bp->b_data;
361 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
362 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
363 	b710 = (struct byte_bpb710 *)bsp->bs710.bsPBP;
364 
365 #ifndef MSDOSFS_NOCHECKSIG
366 	if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
367 	    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
368 		error = EINVAL;
369 		goto error_exit;
370 	}
371 #endif
372 
373 	pmp = kmalloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
374 	pmp->pm_mountp = mp;
375 
376 	/*
377 	 * Compute several useful quantities from the bpb in the
378 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
379 	 * the fields that are different between dos 5 and dos 3.3.
380 	 */
381 	SecPerClust = b50->bpbSecPerClust;
382 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
383 	if (pmp->pm_BytesPerSec < DEV_BSIZE) {
384 		error = EINVAL;
385 		goto error_exit;
386 	}
387 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
388 	pmp->pm_FATs = b50->bpbFATs;
389 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
390 	pmp->pm_Sectors = getushort(b50->bpbSectors);
391 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
392 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
393 	pmp->pm_Heads = getushort(b50->bpbHeads);
394 	pmp->pm_Media = b50->bpbMedia;
395 
396 	/* calculate the ratio of sector size to DEV_BSIZE */
397 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
398 
399 	/*
400 	 * We don't check pm_Heads nor pm_SecPerTrack, because
401 	 * these may not be set for EFI file systems. We don't
402 	 * use these anyway, so we're unaffected if they are
403 	 * invalid.
404 	 */
405 	if (!pmp->pm_BytesPerSec || !SecPerClust) {
406 		error = EINVAL;
407 		goto error_exit;
408 	}
409 
410 	if (pmp->pm_Sectors == 0) {
411 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
412 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
413 	} else {
414 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
415 		pmp->pm_HugeSectors = pmp->pm_Sectors;
416 	}
417 
418 	if (pmp->pm_RootDirEnts == 0) {
419 		if (pmp->pm_Sectors
420 		    || pmp->pm_FATsecs
421 		    || getushort(b710->bpbFSVers)) {
422 			error = EINVAL;
423 			kprintf("mountmsdosfs(): bad FAT32 filesystem\n");
424 			goto error_exit;
425 		}
426 		pmp->pm_fatmask = FAT32_MASK;
427 		pmp->pm_fatmult = 4;
428 		pmp->pm_fatdiv = 1;
429 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
430 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
431 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
432 		else
433 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
434 	} else
435 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
436 
437 	/*
438 	 * Check a few values (could do some more):
439 	 * - logical sector size: power of 2, >= block size
440 	 * - sectors per cluster: power of 2, >= 1
441 	 * - number of sectors:   >= 1, <= size of partition
442 	 * - number of FAT sectors: >= 1
443 	 */
444 	if ( (SecPerClust == 0)
445 	  || (SecPerClust & (SecPerClust - 1))
446 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
447 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
448 	  || (pmp->pm_HugeSectors == 0)
449 	  || (pmp->pm_FATsecs == 0)
450 	  || (SecPerClust * pmp->pm_BlkPerSec > MAXBSIZE / DEV_BSIZE)
451 	) {
452 		error = EINVAL;
453 		goto error_exit;
454 	}
455 
456 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
457 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
458 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
459 	SecPerClust         *= pmp->pm_BlkPerSec;
460 
461 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
462 
463 	if (FAT32(pmp)) {
464 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
465 		pmp->pm_firstcluster = pmp->pm_fatblk
466 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
467 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
468 	} else {
469 		pmp->pm_rootdirblk = pmp->pm_fatblk +
470 			(pmp->pm_FATs * pmp->pm_FATsecs);
471 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
472 				       + DEV_BSIZE - 1)
473 			/ DEV_BSIZE; /* in blocks */
474 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
475 	}
476 
477 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
478 	    SecPerClust + 1;
479 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
480 
481 	if (pmp->pm_fatmask == 0) {
482 		if (pmp->pm_maxcluster
483 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
484 			/*
485 			 * This will usually be a floppy disk. This size makes
486 			 * sure that one fat entry will not be split across
487 			 * multiple blocks.
488 			 */
489 			pmp->pm_fatmask = FAT12_MASK;
490 			pmp->pm_fatmult = 3;
491 			pmp->pm_fatdiv = 2;
492 		} else {
493 			pmp->pm_fatmask = FAT16_MASK;
494 			pmp->pm_fatmult = 2;
495 			pmp->pm_fatdiv = 1;
496 		}
497 	}
498 
499 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
500 	if (pmp->pm_maxcluster >= clusters) {
501 		kprintf("Warning: number of clusters (%ld) exceeds FAT "
502 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
503 		pmp->pm_maxcluster = clusters - 1;
504 	}
505 
506 
507 	if (FAT12(pmp))
508 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
509 	else
510 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
511 
512 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
513 	pmp->pm_bnshift = DEV_BSHIFT;
514 
515 	/*
516 	 * Compute mask and shift value for isolating cluster relative byte
517 	 * offsets and cluster numbers from a file offset.
518 	 */
519 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
520 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
521 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
522 
523 	/*
524 	 * Check for valid cluster size
525 	 * must be a power of 2
526 	 */
527 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
528 		error = EINVAL;
529 		goto error_exit;
530 	}
531 
532 	/*
533 	 * Release the bootsector buffer.
534 	 */
535 	bp->b_flags |= B_RELBUF;
536 	brelse(bp);
537 	bp = NULL;
538 
539 	/*
540 	 * Check FSInfo.
541 	 */
542 	if (pmp->pm_fsinfo) {
543 		struct fsinfo *fp;
544 
545 		if ((error = bread(devvp, de_bntodoff(pmp, pmp->pm_fsinfo), fsi_size(pmp), &bp)) != 0)
546 			goto error_exit;
547 		fp = (struct fsinfo *)bp->b_data;
548 		if (!bcmp(fp->fsisig1, "RRaA", 4) &&
549 		    !bcmp(fp->fsisig2, "rrAa", 4) &&
550 		    !bcmp(fp->fsisig3, "\0\0\125\252", 4) &&
551 		    !bcmp(fp->fsisig4, "\0\0\125\252", 4)) {
552 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
553 			if (pmp->pm_nxtfree == (u_long)-1)
554 				pmp->pm_nxtfree = CLUST_FIRST;
555 			if (pmp->pm_nxtfree == (u_int)-1) {
556 				kprintf("msdosfs_mount(): "
557 					"ignoring illegal nxtfree 0x%016jx\n",
558 					(uintmax_t)pmp->pm_nxtfree);
559 				pmp->pm_nxtfree = CLUST_FIRST;
560 			}
561 		} else
562 			pmp->pm_fsinfo = 0;
563 		bp->b_flags |= B_RELBUF;
564 		brelse(bp);
565 		bp = NULL;
566 	}
567 
568 	/*
569 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
570 	 */
571 	if (pmp->pm_fsinfo && pmp->pm_nxtfree > pmp->pm_maxcluster) {
572 		kprintf(
573 		"Next free cluster in FSInfo (%lu) exceeds maxcluster (%lu)\n",
574 		    pmp->pm_nxtfree, pmp->pm_maxcluster);
575 		error = EINVAL;
576 		goto error_exit;
577 	}
578 
579 	/*
580 	 * Allocate memory for the bitmap of allocated clusters, and then
581 	 * fill it in.
582 	 */
583 	pmp->pm_inusemap = kmalloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
584 				   / N_INUSEBITS)
585 				  * sizeof(*pmp->pm_inusemap),
586 				  M_MSDOSFSFAT, M_WAITOK);
587 
588 	/*
589 	 * fillinusemap() needs pm_devvp.
590 	 */
591 	pmp->pm_dev = dev;
592 	pmp->pm_devvp = devvp;
593 
594 	/*
595 	 * Have the inuse map filled in.
596 	 */
597 	if ((error = fillinusemap(pmp)) != 0)
598 		goto error_exit;
599 
600 	/*
601 	 * If they want fat updates to be synchronous then let them suffer
602 	 * the performance degradation in exchange for the on disk copy of
603 	 * the fat being correct just about all the time.  I suppose this
604 	 * would be a good thing to turn on if the kernel is still flakey.
605 	 */
606 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
607 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
608 
609 	/*
610 	 * Finish up.
611 	 */
612 	if (ronly)
613 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
614 	else
615 		pmp->pm_fmod = 1;
616 	mp->mnt_data = (qaddr_t) pmp;
617 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
618 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
619 	mp->mnt_flag |= MNT_LOCAL;
620 	vfs_add_vnodeops(mp, &msdosfs_vnode_vops, &mp->mnt_vn_norm_ops);
621 	dev->si_mountpoint = mp;
622 
623 	return 0;
624 
625 error_exit:
626 	if (bp) {
627 		bp->b_flags |= B_RELBUF;
628 		brelse(bp);
629 	}
630 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
631 	VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE, NULL);
632 	vn_unlock(devvp);
633 	if (pmp) {
634 		if (pmp->pm_inusemap)
635 			kfree(pmp->pm_inusemap, M_MSDOSFSFAT);
636 		kfree(pmp, M_MSDOSFSMNT);
637 		mp->mnt_data = (qaddr_t)0;
638 	}
639 	return (error);
640 }
641 
642 /*
643  * Unmount the filesystem described by mp.
644  */
645 static int
646 msdosfs_unmount(struct mount *mp, int mntflags)
647 {
648 	struct msdosfsmount *pmp;
649 	int error, flags;
650 
651 	flags = 0;
652 	if (mntflags & MNT_FORCE)
653 		flags |= FORCECLOSE;
654 	error = vflush(mp, 0, flags);
655 	if (error)
656 		return error;
657 	pmp = VFSTOMSDOSFS(mp);
658 	pmp->pm_devvp->v_rdev->si_mountpoint = NULL;
659 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdos_iconv) {
660 		if(pmp->pm_w2u)
661 			msdos_iconv->close(pmp->pm_w2u);
662 		if(pmp->pm_u2w)
663 			msdos_iconv->close(pmp->pm_u2w);
664 		if(pmp->pm_d2u)
665 			msdos_iconv->close(pmp->pm_d2u);
666 		if(pmp->pm_u2d)
667 			msdos_iconv->close(pmp->pm_u2d);
668 	}
669 #ifdef MSDOSFS_DEBUG
670 	{
671 		struct vnode *vp = pmp->pm_devvp;
672 
673 		kprintf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
674 		kprintf("flag %08x, refcnt 0x%08x, writecount %d, "
675 			"auxrefs 0x%08x\n",
676 			vp->v_flag, vp->v_refcnt,
677 			vp->v_writecount, vp->v_auxrefs);
678 		kprintf("mount %p, op %p\n", vp->v_mount, vp->v_ops);
679 		kprintf("mount %p\n", vp->v_mount);
680 		kprintf("cleanblkhd %p, dirtyblkhd %p, numoutput %d, type %d\n",
681 		    RB_ROOT(&vp->v_rbclean_tree),
682 		    RB_ROOT(&vp->v_rbdirty_tree),
683 		    bio_track_active(&vp->v_track_write),
684 		    vp->v_type);
685 		kprintf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
686 		    vp->v_socket, vp->v_tag,
687 		    ((u_int *)vp->v_data)[0],
688 		    ((u_int *)vp->v_data)[1]);
689 	}
690 #endif
691 	vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
692 	error = VOP_CLOSE(pmp->pm_devvp,
693 		    (pmp->pm_flags&MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE,
694 		    NULL);
695 	vn_unlock(pmp->pm_devvp);
696 	vrele(pmp->pm_devvp);
697 	kfree(pmp->pm_inusemap, M_MSDOSFSFAT);
698 	kfree(pmp, M_MSDOSFSMNT);
699 	mp->mnt_data = (qaddr_t)0;
700 	mp->mnt_flag &= ~MNT_LOCAL;
701 	return (error);
702 }
703 
704 static int
705 msdosfs_root(struct mount *mp, struct vnode **vpp)
706 {
707 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
708 	struct denode *ndep;
709 	int error;
710 
711 #ifdef MSDOSFS_DEBUG
712 	kprintf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
713 #endif
714 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
715 	if (error)
716 		return (error);
717 	*vpp = DETOV(ndep);
718 	return (0);
719 }
720 
721 static int
722 msdosfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
723 {
724 	struct msdosfsmount *pmp;
725 
726 	pmp = VFSTOMSDOSFS(mp);
727 	sbp->f_bsize = pmp->pm_bpcluster;
728 	sbp->f_iosize = pmp->pm_bpcluster;
729 	sbp->f_blocks = pmp->pm_maxcluster + 1;
730 	sbp->f_bfree = pmp->pm_freeclustercount;
731 	sbp->f_bavail = pmp->pm_freeclustercount;
732 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
733 	sbp->f_ffree = 0;	/* what to put in here? */
734 	if (sbp != &mp->mnt_stat) {
735 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
736 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
737 	}
738 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
739 	return (0);
740 }
741 
742 struct scaninfo {
743 	int rescan;
744 	int allerror;
745 	int waitfor;
746 };
747 
748 static int msdosfs_sync_scan(struct mount *mp, struct vnode *vp, void *data);
749 
750 static int
751 msdosfs_sync(struct mount *mp, int waitfor)
752 {
753 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
754 	struct scaninfo scaninfo;
755 	int error;
756 
757 	/*
758 	 * If we ever switch to not updating all of the fats all the time,
759 	 * this would be the place to update them from the first one.
760 	 */
761 	if (pmp->pm_fmod != 0) {
762 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
763 			panic("msdosfs_sync: rofs mod");
764 		else {
765 			/* update fats here */
766 		}
767 	}
768 	/*
769 	 * Write back each (modified) denode.
770 	 */
771 	scaninfo.allerror = 0;
772 	scaninfo.rescan = 1;
773 	while (scaninfo.rescan) {
774 		scaninfo.rescan = 0;
775 		vmntvnodescan(mp, VMSC_GETVP|VMSC_NOWAIT, NULL, msdosfs_sync_scan, &scaninfo);
776 	}
777 
778 	/*
779 	 * Flush filesystem control info.
780 	 */
781 	if ((waitfor & MNT_LAZY) == 0) {
782 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
783 		if ((error = VOP_FSYNC(pmp->pm_devvp, waitfor, 0)) != 0)
784 			scaninfo.allerror = error;
785 		vn_unlock(pmp->pm_devvp);
786 	}
787 	return (scaninfo.allerror);
788 }
789 
790 static int
791 msdosfs_sync_scan(struct mount *mp, struct vnode *vp, void *data)
792 {
793 	struct scaninfo *info = data;
794 	struct denode *dep;
795 	int error;
796 
797 	dep = VTODE(vp);
798 	if (vp->v_type == VNON || vp->v_type == VBAD ||
799 	    ((dep->de_flag &
800 	    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
801 	    (RB_EMPTY(&vp->v_rbdirty_tree) || (info->waitfor & MNT_LAZY)))) {
802 		return(0);
803 	}
804 	if ((error = VOP_FSYNC(vp, info->waitfor, 0)) != 0)
805 		info->allerror = error;
806 	return(0);
807 }
808 
809 static int
810 msdosfs_fhtovp(struct mount *mp, struct vnode *rootvp,
811 	       struct fid *fhp, struct vnode **vpp)
812 {
813 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
814 	struct defid *defhp = (struct defid *) fhp;
815 	struct denode *dep;
816 	int error;
817 
818 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
819 	if (error) {
820 		*vpp = NULLVP;
821 		return (error);
822 	}
823 	*vpp = DETOV(dep);
824 	return (0);
825 }
826 
827 static int
828 msdosfs_checkexp(struct mount *mp, struct sockaddr *nam, int *exflagsp,
829 		 struct ucred **credanonp)
830 {
831 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
832 	struct netcred *np;
833 
834 	np = vfs_export_lookup(mp, &pmp->pm_export, nam);
835 	if (np == NULL)
836 		return (EACCES);
837 	*exflagsp = np->netc_exflags;
838 	*credanonp = &np->netc_anon;
839 	return (0);
840 }
841 
842 static int
843 msdosfs_vptofh(struct vnode *vp, struct fid *fhp)
844 {
845 	struct denode *dep;
846 	struct defid *defhp;
847 
848 	dep = VTODE(vp);
849 	defhp = (struct defid *)fhp;
850 	defhp->defid_len = sizeof(struct defid);
851 	defhp->defid_dirclust = dep->de_dirclust;
852 	defhp->defid_dirofs = dep->de_diroffset;
853 	/* defhp->defid_gen = dep->de_gen; */
854 	return (0);
855 }
856 
857 static struct vfsops msdosfs_vfsops = {
858 	.vfs_mount =     	msdosfs_mount,
859 	.vfs_unmount =   	msdosfs_unmount,
860 	.vfs_root =     	msdosfs_root,
861 	.vfs_statfs =   	msdosfs_statfs,
862 	.vfs_sync =     	msdosfs_sync,
863 	.vfs_fhtovp =   	msdosfs_fhtovp,
864 	.vfs_checkexp =  	msdosfs_checkexp,
865 	.vfs_vptofh =   	msdosfs_vptofh,
866 	.vfs_init =     	msdosfs_init,
867 	.vfs_uninit =   	msdosfs_uninit
868 };
869 
870 VFS_SET(msdosfs_vfsops, msdos, 0);
871 MODULE_VERSION(msdos, 1);
872