xref: /dragonfly/sys/vfs/msdosfs/msdosfs_vfsops.c (revision cc93b0eb)
1 /* $FreeBSD: /usr/local/www/cvsroot/FreeBSD/src/sys/msdosfs/Attic/msdosfs_vfsops.c,v 1.60.2.8 2004/03/02 09:43:04 tjr Exp $ */
2 /* $DragonFly: src/sys/vfs/msdosfs/msdosfs_vfsops.c,v 1.51 2008/05/20 19:14:38 dillon Exp $ */
3 /*	$NetBSD: msdosfs_vfsops.c,v 1.51 1997/11/17 15:36:58 ws Exp $	*/
4 
5 /*-
6  * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
7  * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
8  * All rights reserved.
9  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by TooLs GmbH.
22  * 4. The name of TooLs GmbH may not be used to endorse or promote products
23  *    derived from this software without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
29  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
30  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
31  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
32  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
33  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
34  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35  */
36 /*
37  * Written by Paul Popelka (paulp@uts.amdahl.com)
38  *
39  * You can do anything you want with this software, just don't say you wrote
40  * it, and don't remove this notice.
41  *
42  * This software is provided "as is".
43  *
44  * The author supplies this software to be publicly redistributed on the
45  * understanding that the author is not responsible for the correct
46  * functioning of this software in any circumstances and is not liable for
47  * any damages caused by this software.
48  *
49  * October 1992
50  */
51 
52 #include <sys/param.h>
53 #include <sys/systm.h>
54 #include <sys/conf.h>
55 #include <sys/proc.h>
56 #include <sys/nlookup.h>
57 #include <sys/kernel.h>
58 #include <sys/vnode.h>
59 #include <sys/mount.h>
60 #include <sys/buf.h>
61 #include <sys/fcntl.h>
62 #include <sys/malloc.h>
63 #include <sys/stat.h> 				/* defines ALLPERMS */
64 #include <vm/vm_zone.h>
65 
66 #include "bpb.h"
67 #include "bootsect.h"
68 #include "direntry.h"
69 #include "denode.h"
70 #include "msdosfsmount.h"
71 #include "fat.h"
72 
73 extern struct vop_ops msdosfs_vnode_vops;
74 
75 #define MSDOSFS_DFLTBSIZE       4096
76 
77 #if 1 /*def PC98*/
78 /*
79  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
80  *       garbage or a random value :-{
81  *       If you want to use that broken-signatured media, define the
82  *       following symbol even though PC/AT.
83  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
84  */
85 #define	MSDOSFS_NOCHECKSIG
86 #endif
87 
88 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOSFS mount structure");
89 static MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOSFS file allocation table");
90 
91 static int	update_mp (struct mount *mp, struct msdosfs_args *argp);
92 static int	mountmsdosfs (struct vnode *devvp, struct mount *mp,
93 				  struct msdosfs_args *argp);
94 static int	msdosfs_fhtovp (struct mount *, struct fid *,
95 				    struct vnode **);
96 static int	msdosfs_checkexp (struct mount *, struct sockaddr *,
97 				    int *, struct ucred **);
98 static int	msdosfs_mount (struct mount *, char *, caddr_t,
99 				   struct ucred *);
100 static int	msdosfs_root (struct mount *, struct vnode **);
101 static int	msdosfs_statfs (struct mount *, struct statfs *,
102 				struct ucred *);
103 static int	msdosfs_sync (struct mount *, int);
104 static int	msdosfs_unmount (struct mount *, int);
105 static int	msdosfs_vptofh (struct vnode *, struct fid *);
106 
107 static int
108 update_mp(struct mount *mp, struct msdosfs_args *argp)
109 {
110 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
111 	int error;
112 
113 	pmp->pm_gid = argp->gid;
114 	pmp->pm_uid = argp->uid;
115 	pmp->pm_mask = argp->mask & ALLPERMS;
116 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
117 	if (pmp->pm_flags & MSDOSFSMNT_U2WTABLE) {
118 		bcopy(argp->u2w, pmp->pm_u2w, sizeof(pmp->pm_u2w));
119 		bcopy(argp->d2u, pmp->pm_d2u, sizeof(pmp->pm_d2u));
120 		bcopy(argp->u2d, pmp->pm_u2d, sizeof(pmp->pm_u2d));
121 	}
122 	if (pmp->pm_flags & MSDOSFSMNT_ULTABLE) {
123 		bcopy(argp->ul, pmp->pm_ul, sizeof(pmp->pm_ul));
124 		bcopy(argp->lu, pmp->pm_lu, sizeof(pmp->pm_lu));
125 	}
126 
127 #ifndef __DragonFly__
128 	/*
129 	 * GEMDOS knows nothing (yet) about win95
130 	 */
131 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
132 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
133 #endif
134 
135 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
136 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
137 	else if (!(pmp->pm_flags &
138 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
139 		struct vnode *rootvp;
140 
141 		/*
142 		 * Try to divine whether to support Win'95 long filenames
143 		 */
144 		if (FAT32(pmp))
145 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
146 		else {
147 			if ((error = msdosfs_root(mp, &rootvp)) != 0)
148 				return error;
149 			pmp->pm_flags |= findwin95(VTODE(rootvp))
150 				? MSDOSFSMNT_LONGNAME
151 					: MSDOSFSMNT_SHORTNAME;
152 			vput(rootvp);
153 		}
154 	}
155 	return 0;
156 }
157 
158 /*
159  * mp - path - addr in user space of mount point (ie /usr or whatever)
160  * data - addr in user space of mount params including the name of the block
161  * special file to treat as a filesystem.
162  */
163 static int
164 msdosfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
165 {
166 	struct vnode *devvp;	  /* vnode for blk device to mount */
167 	struct msdosfs_args args; /* will hold data from mount request */
168 	/* msdosfs specific mount control block */
169 	struct msdosfsmount *pmp = NULL;
170 	size_t size;
171 	int error, flags;
172 	mode_t accessmode;
173 	struct nlookupdata nd;
174 
175 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
176 	if (error)
177 		return (error);
178 	if (args.magic != MSDOSFS_ARGSMAGIC)
179 		args.flags = 0;
180 	/*
181 	 * If updating, check whether changing from read-only to
182 	 * read/write; if there is no device name, that's all we do.
183 	 */
184 	if (mp->mnt_flag & MNT_UPDATE) {
185 		pmp = VFSTOMSDOSFS(mp);
186 		error = 0;
187 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
188 			flags = WRITECLOSE;
189 			if (mp->mnt_flag & MNT_FORCE)
190 				flags |= FORCECLOSE;
191 			error = vflush(mp, 0, flags);
192 			if (error == 0) {
193 				devvp = pmp->pm_devvp;
194 				VOP_OPEN(devvp, FREAD, FSCRED, NULL);
195 				VOP_CLOSE(devvp, FREAD|FWRITE);
196 				pmp->pm_flags |= MSDOSFSMNT_RONLY;
197 			}
198 		}
199 		if (!error && (mp->mnt_flag & MNT_RELOAD))
200 			/* not yet implemented */
201 			error = EOPNOTSUPP;
202 		if (error)
203 			return (error);
204 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
205 			/*
206 			 * If upgrade to read-write by non-root, then verify
207 			 * that user has necessary permissions on the device.
208 			 */
209 			devvp = pmp->pm_devvp;
210 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
211 			if (cred->cr_uid != 0) {
212 				error = VOP_ACCESS(devvp, VREAD | VWRITE, cred);
213 				if (error) {
214 					vn_unlock(devvp);
215 					return (error);
216 				}
217 			}
218 			VOP_OPEN(devvp, FREAD|FWRITE, FSCRED, NULL);
219 			VOP_CLOSE(devvp, FREAD);
220 			vn_unlock(devvp);
221 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
222 		}
223 		if (args.fspec == 0) {
224 #ifdef	__notyet__		/* doesn't work correctly with current mountd	XXX */
225 			if (args.flags & MSDOSFSMNT_MNTOPT) {
226 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
227 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
228 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
229 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
230 			}
231 #endif
232 			/*
233 			 * Process export requests.
234 			 */
235 			return (vfs_export(mp, &pmp->pm_export, &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 block device.
241 	 */
242 	devvp = NULL;
243 	error = nlookup_init(&nd, args.fspec, UIO_USERSPACE, NLC_FOLLOW);
244 	if (error == 0)
245 		error = nlookup(&nd);
246 	if (error == 0)
247 		error = cache_vref(&nd.nl_nch, nd.nl_cred, &devvp);
248 	nlookup_done(&nd);
249 	if (error)
250 		return (error);
251 
252 	if (!vn_isdisk(devvp, &error)) {
253 		vrele(devvp);
254 		return (error);
255 	}
256 	/*
257 	 * If mount by non-root, then verify that user has necessary
258 	 * permissions on the device.
259 	 */
260 	if (cred->cr_uid != 0) {
261 		accessmode = VREAD;
262 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
263 			accessmode |= VWRITE;
264 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
265 		error = VOP_ACCESS(devvp, accessmode, cred);
266 		if (error) {
267 			vput(devvp);
268 			return (error);
269 		}
270 		vn_unlock(devvp);
271 	}
272 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
273 		error = mountmsdosfs(devvp, mp, &args);
274 #ifdef MSDOSFS_DEBUG		/* only needed for the kprintf below */
275 		pmp = VFSTOMSDOSFS(mp);
276 #endif
277 	} else {
278 		if (devvp != pmp->pm_devvp)
279 			error = EINVAL;	/* XXX needs translation */
280 		else
281 			vrele(devvp);
282 	}
283 	if (error) {
284 		vrele(devvp);
285 		return (error);
286 	}
287 
288 	error = update_mp(mp, &args);
289 	if (error) {
290 		msdosfs_unmount(mp, MNT_FORCE);
291 		return error;
292 	}
293 
294 	copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &size);
295 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
296 	msdosfs_statfs(mp, &mp->mnt_stat, cred);
297 #ifdef MSDOSFS_DEBUG
298 	kprintf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
299 #endif
300 	return (0);
301 }
302 
303 static int
304 mountmsdosfs(struct vnode *devvp, struct mount *mp, struct msdosfs_args *argp)
305 {
306 	struct msdosfsmount *pmp;
307 	struct buf *bp;
308 	cdev_t dev;
309 	union bootsector *bsp;
310 	struct byte_bpb33 *b33;
311 	struct byte_bpb50 *b50;
312 	struct byte_bpb710 *b710;
313 	u_int8_t SecPerClust;
314 	u_long clusters;
315 	int	ronly, error;
316 
317 	/*
318 	 * Disallow multiple mounts of the same device.
319 	 * Disallow mounting of a device that is currently in use
320 	 * Flush out any old buffers remaining from a previous use.
321 	 */
322 	error = vfs_mountedon(devvp);
323 	if (error)
324 		return (error);
325 	if (count_udev(devvp->v_umajor, devvp->v_uminor) > 0)
326 		return (EBUSY);
327 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
328 	error = vinvalbuf(devvp, V_SAVE, 0, 0);
329 	vn_unlock(devvp);
330 	if (error)
331 		return (error);
332 
333 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
334 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
335 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, NULL);
336 	vn_unlock(devvp);
337 	if (error)
338 		return (error);
339 	dev = devvp->v_rdev;
340 	bp  = NULL; /* both used in error_exit */
341 	pmp = NULL;
342 
343 	/*
344 	 * Read the boot sector of the filesystem, and then check the
345 	 * boot signature.  If not a dos boot sector then error out.
346 	 *
347 	 * NOTE: 2048 is a maximum sector size in current...
348 	 */
349 	error = bread(devvp, 0, 2048, &bp);
350 	if (error)
351 		goto error_exit;
352 	bp->b_flags |= B_AGE;
353 	bsp = (union bootsector *)bp->b_data;
354 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
355 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
356 	b710 = (struct byte_bpb710 *)bsp->bs710.bsPBP;
357 
358 #ifndef __DragonFly__
359 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
360 #endif
361 #ifndef MSDOSFS_NOCHECKSIG
362 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
363 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
364 			error = EINVAL;
365 			goto error_exit;
366 		}
367 #endif
368 #ifndef __DragonFly__
369 	}
370 #endif
371 
372 	pmp = kmalloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
373 	pmp->pm_mountp = mp;
374 
375 	/*
376 	 * Compute several useful quantities from the bpb in the
377 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
378 	 * the fields that are different between dos 5 and dos 3.3.
379 	 */
380 	SecPerClust = b50->bpbSecPerClust;
381 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
382 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
383 	pmp->pm_FATs = b50->bpbFATs;
384 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
385 	pmp->pm_Sectors = getushort(b50->bpbSectors);
386 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
387 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
388 	pmp->pm_Heads = getushort(b50->bpbHeads);
389 	pmp->pm_Media = b50->bpbMedia;
390 
391 	/* calculate the ratio of sector size to DEV_BSIZE */
392 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
393 
394 #ifndef __DragonFly__
395 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
396 #endif
397 		/* XXX - We should probably check more values here */
398 		if (!pmp->pm_BytesPerSec || !SecPerClust
399 			|| !pmp->pm_Heads
400 			|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
401 			error = EINVAL;
402 			goto error_exit;
403 		}
404 #ifndef __DragonFly__
405 	}
406 #endif
407 
408 	if (pmp->pm_Sectors == 0) {
409 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
410 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
411 	} else {
412 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
413 		pmp->pm_HugeSectors = pmp->pm_Sectors;
414 	}
415 
416 	if (pmp->pm_RootDirEnts == 0) {
417 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
418 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
419 		    || 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 	 */
443 	if ( (SecPerClust == 0)
444 	  || (SecPerClust & (SecPerClust - 1))
445 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
446 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
447 	  || (pmp->pm_HugeSectors == 0)
448 	) {
449 		error = EINVAL;
450 		goto error_exit;
451 	}
452 
453 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
454 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
455 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
456 	SecPerClust         *= pmp->pm_BlkPerSec;
457 
458 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
459 
460 	if (FAT32(pmp)) {
461 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
462 		pmp->pm_firstcluster = pmp->pm_fatblk
463 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
464 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
465 	} else {
466 		pmp->pm_rootdirblk = pmp->pm_fatblk +
467 			(pmp->pm_FATs * pmp->pm_FATsecs);
468 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
469 				       + DEV_BSIZE - 1)
470 			/ DEV_BSIZE; /* in blocks */
471 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
472 	}
473 
474 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
475 	    SecPerClust + 1;
476 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
477 
478 #ifndef __DragonFly__
479 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
480 		if ((pmp->pm_maxcluster <= (0xff0 - 2))
481 		      && ((dtype == DTYPE_FLOPPY) || ((dtype == DTYPE_VNODE)
482 		      && ((pmp->pm_Heads == 1) || (pmp->pm_Heads == 2))))
483 		    ) {
484 			pmp->pm_fatmask = FAT12_MASK;
485 			pmp->pm_fatmult = 3;
486 			pmp->pm_fatdiv = 2;
487 		} else {
488 			pmp->pm_fatmask = FAT16_MASK;
489 			pmp->pm_fatmult = 2;
490 			pmp->pm_fatdiv = 1;
491 		}
492 	} else
493 #endif
494 	if (pmp->pm_fatmask == 0) {
495 		if (pmp->pm_maxcluster
496 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
497 			/*
498 			 * This will usually be a floppy disk. This size makes
499 			 * sure that one fat entry will not be split across
500 			 * multiple blocks.
501 			 */
502 			pmp->pm_fatmask = FAT12_MASK;
503 			pmp->pm_fatmult = 3;
504 			pmp->pm_fatdiv = 2;
505 		} else {
506 			pmp->pm_fatmask = FAT16_MASK;
507 			pmp->pm_fatmult = 2;
508 			pmp->pm_fatdiv = 1;
509 		}
510 	}
511 
512 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
513 	if (pmp->pm_maxcluster >= clusters) {
514 		kprintf("Warning: number of clusters (%ld) exceeds FAT "
515 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
516 		pmp->pm_maxcluster = clusters - 1;
517 	}
518 
519 
520 	if (FAT12(pmp))
521 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
522 	else
523 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
524 
525 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
526 	pmp->pm_bnshift = DEV_BSHIFT;
527 
528 	/*
529 	 * Compute mask and shift value for isolating cluster relative byte
530 	 * offsets and cluster numbers from a file offset.
531 	 */
532 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
533 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
534 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
535 
536 	/*
537 	 * Check for valid cluster size
538 	 * must be a power of 2
539 	 */
540 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
541 		error = EINVAL;
542 		goto error_exit;
543 	}
544 
545 	/*
546 	 * Release the bootsector buffer.
547 	 */
548 	brelse(bp);
549 	bp = NULL;
550 
551 	/*
552 	 * Check FSInfo.
553 	 */
554 	if (pmp->pm_fsinfo) {
555 		struct fsinfo *fp;
556 
557 		if ((error = bread(devvp, de_bntodoff(pmp, pmp->pm_fsinfo), fsi_size(pmp), &bp)) != 0)
558 			goto error_exit;
559 		fp = (struct fsinfo *)bp->b_data;
560 		if (!bcmp(fp->fsisig1, "RRaA", 4)
561 		    && !bcmp(fp->fsisig2, "rrAa", 4)
562 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
563 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4)) {
564 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
565 			if (pmp->pm_nxtfree == 0xffffffff)
566 				pmp->pm_nxtfree = CLUST_FIRST;
567 		} else
568 			pmp->pm_fsinfo = 0;
569 		brelse(bp);
570 		bp = NULL;
571 	}
572 
573 	/*
574 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
575 	 */
576 	if (pmp->pm_fsinfo && pmp->pm_nxtfree > pmp->pm_maxcluster) {
577 		kprintf(
578 		"Next free cluster in FSInfo (%lu) exceeds maxcluster (%lu)\n",
579 		    pmp->pm_nxtfree, pmp->pm_maxcluster);
580 		error = EINVAL;
581 		goto error_exit;
582 	}
583 
584 	/*
585 	 * Allocate memory for the bitmap of allocated clusters, and then
586 	 * fill it in.
587 	 */
588 	pmp->pm_inusemap = kmalloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
589 				   / N_INUSEBITS)
590 				  * sizeof(*pmp->pm_inusemap),
591 				  M_MSDOSFSFAT, M_WAITOK);
592 
593 	/*
594 	 * fillinusemap() needs pm_devvp.
595 	 */
596 	pmp->pm_dev = dev;
597 	pmp->pm_devvp = devvp;
598 
599 	/*
600 	 * Have the inuse map filled in.
601 	 */
602 	if ((error = fillinusemap(pmp)) != 0)
603 		goto error_exit;
604 
605 	/*
606 	 * If they want fat updates to be synchronous then let them suffer
607 	 * the performance degradation in exchange for the on disk copy of
608 	 * the fat being correct just about all the time.  I suppose this
609 	 * would be a good thing to turn on if the kernel is still flakey.
610 	 */
611 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
612 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
613 
614 	/*
615 	 * Finish up.
616 	 */
617 	if (ronly)
618 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
619 	else
620 		pmp->pm_fmod = 1;
621 	mp->mnt_data = (qaddr_t) pmp;
622 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
623 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
624 	mp->mnt_flag |= MNT_LOCAL;
625 	vfs_add_vnodeops(mp, &msdosfs_vnode_vops, &mp->mnt_vn_norm_ops);
626 	dev->si_mountpoint = mp;
627 
628 	return 0;
629 
630 error_exit:
631 	if (bp)
632 		brelse(bp);
633 	VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE);
634 	if (pmp) {
635 		if (pmp->pm_inusemap)
636 			kfree(pmp->pm_inusemap, M_MSDOSFSFAT);
637 		kfree(pmp, M_MSDOSFSMNT);
638 		mp->mnt_data = (qaddr_t)0;
639 	}
640 	return (error);
641 }
642 
643 /*
644  * Unmount the filesystem described by mp.
645  */
646 static int
647 msdosfs_unmount(struct mount *mp, int mntflags)
648 {
649 	struct msdosfsmount *pmp;
650 	int error, flags;
651 
652 	flags = 0;
653 	if (mntflags & MNT_FORCE)
654 		flags |= FORCECLOSE;
655 	error = vflush(mp, 0, flags);
656 	if (error)
657 		return error;
658 	pmp = VFSTOMSDOSFS(mp);
659 	pmp->pm_devvp->v_rdev->si_mountpoint = NULL;
660 #ifdef MSDOSFS_DEBUG
661 	{
662 		struct vnode *vp = pmp->pm_devvp;
663 
664 		kprintf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
665 		kprintf("flag %08x, sysrefs %d, writecount %d, auxrefs %d\n",
666 		    vp->v_flag, vp->v_sysref.refcnt,
667 		    vp->v_writecount, vp->v_auxrefs);
668 		kprintf("mount %p, op %p\n", vp->v_mount, vp->v_ops);
669 		kprintf("mount %p\n", vp->v_mount);
670 		kprintf("cleanblkhd %p, dirtyblkhd %p, numoutput %d, type %d\n",
671 		    RB_ROOT(&vp->v_rbclean_tree),
672 		    RB_ROOT(&vp->v_rbdirty_tree),
673 		    vp->v_track_write.bk_active, vp->v_type);
674 		kprintf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
675 		    vp->v_socket, vp->v_tag,
676 		    ((u_int *)vp->v_data)[0],
677 		    ((u_int *)vp->v_data)[1]);
678 	}
679 #endif
680 	error = VOP_CLOSE(pmp->pm_devvp,
681 		    (pmp->pm_flags&MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE);
682 	vrele(pmp->pm_devvp);
683 	kfree(pmp->pm_inusemap, M_MSDOSFSFAT);
684 	kfree(pmp, M_MSDOSFSMNT);
685 	mp->mnt_data = (qaddr_t)0;
686 	mp->mnt_flag &= ~MNT_LOCAL;
687 	return (error);
688 }
689 
690 static int
691 msdosfs_root(struct mount *mp, struct vnode **vpp)
692 {
693 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
694 	struct denode *ndep;
695 	int error;
696 
697 #ifdef MSDOSFS_DEBUG
698 	kprintf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
699 #endif
700 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
701 	if (error)
702 		return (error);
703 	*vpp = DETOV(ndep);
704 	return (0);
705 }
706 
707 static int
708 msdosfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
709 {
710 	struct msdosfsmount *pmp;
711 
712 	pmp = VFSTOMSDOSFS(mp);
713 	sbp->f_bsize = pmp->pm_bpcluster;
714 	sbp->f_iosize = pmp->pm_bpcluster;
715 	sbp->f_blocks = pmp->pm_maxcluster + 1;
716 	sbp->f_bfree = pmp->pm_freeclustercount;
717 	sbp->f_bavail = pmp->pm_freeclustercount;
718 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
719 	sbp->f_ffree = 0;	/* what to put in here? */
720 	if (sbp != &mp->mnt_stat) {
721 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
722 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
723 	}
724 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
725 	return (0);
726 }
727 
728 struct scaninfo {
729 	int rescan;
730 	int allerror;
731 	int waitfor;
732 };
733 
734 static int msdosfs_sync_scan(struct mount *mp, struct vnode *vp, void *data);
735 
736 static int
737 msdosfs_sync(struct mount *mp, int waitfor)
738 {
739 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
740 	struct scaninfo scaninfo;
741 	int error;
742 
743 	/*
744 	 * If we ever switch to not updating all of the fats all the time,
745 	 * this would be the place to update them from the first one.
746 	 */
747 	if (pmp->pm_fmod != 0) {
748 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
749 			panic("msdosfs_sync: rofs mod");
750 		else {
751 			/* update fats here */
752 		}
753 	}
754 	/*
755 	 * Write back each (modified) denode.
756 	 */
757 	scaninfo.allerror = 0;
758 	scaninfo.rescan = 1;
759 	while (scaninfo.rescan) {
760 		scaninfo.rescan = 0;
761 		vmntvnodescan(mp, VMSC_GETVP|VMSC_NOWAIT, NULL, msdosfs_sync_scan, &scaninfo);
762 	}
763 
764 	/*
765 	 * Flush filesystem control info.
766 	 */
767 	if (waitfor != MNT_LAZY) {
768 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
769 		if ((error = VOP_FSYNC(pmp->pm_devvp, waitfor)) != 0)
770 			scaninfo.allerror = error;
771 		vn_unlock(pmp->pm_devvp);
772 	}
773 	return (scaninfo.allerror);
774 }
775 
776 static int
777 msdosfs_sync_scan(struct mount *mp, struct vnode *vp, void *data)
778 {
779 	struct scaninfo *info = data;
780 	struct denode *dep;
781 	int error;
782 
783 	dep = VTODE(vp);
784 	if (vp->v_type == VNON || vp->v_type == VBAD ||
785 	    ((dep->de_flag &
786 	    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
787 	    (RB_EMPTY(&vp->v_rbdirty_tree) || info->waitfor == MNT_LAZY))) {
788 		return(0);
789 	}
790 	if ((error = VOP_FSYNC(vp, info->waitfor)) != 0)
791 		info->allerror = error;
792 	return(0);
793 }
794 
795 static int
796 msdosfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
797 {
798 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
799 	struct defid *defhp = (struct defid *) fhp;
800 	struct denode *dep;
801 	int error;
802 
803 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
804 	if (error) {
805 		*vpp = NULLVP;
806 		return (error);
807 	}
808 	*vpp = DETOV(dep);
809 	return (0);
810 }
811 
812 static int
813 msdosfs_checkexp(struct mount *mp, struct sockaddr *nam, int *exflagsp,
814 		 struct ucred **credanonp)
815 {
816 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
817 	struct netcred *np;
818 
819 	np = vfs_export_lookup(mp, &pmp->pm_export, nam);
820 	if (np == NULL)
821 		return (EACCES);
822 	*exflagsp = np->netc_exflags;
823 	*credanonp = &np->netc_anon;
824 	return (0);
825 }
826 
827 static int
828 msdosfs_vptofh(struct vnode *vp, struct fid *fhp)
829 {
830 	struct denode *dep;
831 	struct defid *defhp;
832 
833 	dep = VTODE(vp);
834 	defhp = (struct defid *)fhp;
835 	defhp->defid_len = sizeof(struct defid);
836 	defhp->defid_dirclust = dep->de_dirclust;
837 	defhp->defid_dirofs = dep->de_diroffset;
838 	/* defhp->defid_gen = dep->de_gen; */
839 	return (0);
840 }
841 
842 static struct vfsops msdosfs_vfsops = {
843 	.vfs_mount =     	msdosfs_mount,
844 	.vfs_unmount =   	msdosfs_unmount,
845 	.vfs_root =     	msdosfs_root,
846 	.vfs_statfs =   	msdosfs_statfs,
847 	.vfs_sync =     	msdosfs_sync,
848 	.vfs_fhtovp =   	msdosfs_fhtovp,
849 	.vfs_checkexp =  	msdosfs_checkexp,
850 	.vfs_vptofh =   	msdosfs_vptofh,
851 	.vfs_init =     	msdosfs_init,
852 	.vfs_uninit =   	msdosfs_uninit
853 };
854 
855 VFS_SET(msdosfs_vfsops, msdos, 0);
856