xref: /dragonfly/sys/vfs/msdosfs/msdosfs_vfsops.c (revision 1847e88f)
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 1.30 2006/02/17 19:18:07 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 vnodeopv_entry_desc msdosfs_vnodeop_entries[];
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 thread *td, 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 thread *);
100 static int	msdosfs_root (struct mount *, struct vnode **);
101 static int	msdosfs_statfs (struct mount *, struct statfs *,
102 				    struct thread *);
103 static int	msdosfs_sync (struct mount *, int, struct thread *);
104 static int	msdosfs_unmount (struct mount *, int, struct thread *);
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 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 	struct proc *p = td->td_proc;
174 	struct nlookupdata nd;
175 
176 	KKASSERT(p);
177 
178 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
179 	if (error)
180 		return (error);
181 	if (args.magic != MSDOSFS_ARGSMAGIC)
182 		args.flags = 0;
183 	/*
184 	 * If updating, check whether changing from read-only to
185 	 * read/write; if there is no device name, that's all we do.
186 	 */
187 	if (mp->mnt_flag & MNT_UPDATE) {
188 		pmp = VFSTOMSDOSFS(mp);
189 		error = 0;
190 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
191 			flags = WRITECLOSE;
192 			if (mp->mnt_flag & MNT_FORCE)
193 				flags |= FORCECLOSE;
194 			error = vflush(mp, 0, flags);
195 		}
196 		if (!error && (mp->mnt_flag & MNT_RELOAD))
197 			/* not yet implemented */
198 			error = EOPNOTSUPP;
199 		if (error)
200 			return (error);
201 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
202 			/*
203 			 * If upgrade to read-write by non-root, then verify
204 			 * that user has necessary permissions on the device.
205 			 */
206 			if (p->p_ucred->cr_uid != 0) {
207 				devvp = pmp->pm_devvp;
208 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
209 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
210 						   p->p_ucred, td);
211 				if (error) {
212 					VOP_UNLOCK(devvp, 0, td);
213 					return (error);
214 				}
215 				VOP_UNLOCK(devvp, 0, td);
216 			}
217 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
218 		}
219 		if (args.fspec == 0) {
220 #ifdef	__notyet__		/* doesn't work correctly with current mountd	XXX */
221 			if (args.flags & MSDOSFSMNT_MNTOPT) {
222 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
223 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
224 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
225 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
226 			}
227 #endif
228 			/*
229 			 * Process export requests.
230 			 */
231 			return (vfs_export(mp, &pmp->pm_export, &args.export));
232 		}
233 	}
234 	/*
235 	 * Not an update, or updating the name: look up the name
236 	 * and verify that it refers to a sensible block device.
237 	 */
238 	devvp = NULL;
239 	error = nlookup_init(&nd, args.fspec, UIO_USERSPACE, NLC_FOLLOW);
240 	if (error == 0)
241 		error = nlookup(&nd);
242 	if (error == 0)
243 		error = cache_vref(nd.nl_ncp, nd.nl_cred, &devvp);
244 	nlookup_done(&nd);
245 	if (error)
246 		return (error);
247 
248 	if (!vn_isdisk(devvp, &error)) {
249 		vrele(devvp);
250 		return (error);
251 	}
252 	/*
253 	 * If mount by non-root, then verify that user has necessary
254 	 * permissions on the device.
255 	 */
256 	if (p->p_ucred->cr_uid != 0) {
257 		accessmode = VREAD;
258 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
259 			accessmode |= VWRITE;
260 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
261 		error = VOP_ACCESS(devvp, accessmode, p->p_ucred, td);
262 		if (error) {
263 			vput(devvp);
264 			return (error);
265 		}
266 		VOP_UNLOCK(devvp, 0, td);
267 	}
268 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
269 		error = mountmsdosfs(devvp, mp, td, &args);
270 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
271 		pmp = VFSTOMSDOSFS(mp);
272 #endif
273 	} else {
274 		if (devvp != pmp->pm_devvp)
275 			error = EINVAL;	/* XXX needs translation */
276 		else
277 			vrele(devvp);
278 	}
279 	if (error) {
280 		vrele(devvp);
281 		return (error);
282 	}
283 
284 	error = update_mp(mp, &args);
285 	if (error) {
286 		msdosfs_unmount(mp, MNT_FORCE, td);
287 		return error;
288 	}
289 
290 	copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &size);
291 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
292 	msdosfs_statfs(mp, &mp->mnt_stat, td);
293 #ifdef MSDOSFS_DEBUG
294 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
295 #endif
296 	return (0);
297 }
298 
299 static int
300 mountmsdosfs(struct vnode *devvp, struct mount *mp, struct thread *td,
301 	     struct msdosfs_args *argp)
302 {
303 	struct msdosfsmount *pmp;
304 	struct buf *bp;
305 	dev_t dev;
306 #ifndef __DragonFly__
307 	struct partinfo dpart;
308 	int bsize = 0, dtype = 0, tmp;
309 #endif
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 	 * Flush out any old buffers remaining from a previous use.
322 	 */
323 	error = vfs_mountedon(devvp);
324 	if (error)
325 		return (error);
326 	if (count_udev(devvp->v_udev) > 0)
327 		return (EBUSY);
328 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
329 	error = vinvalbuf(devvp, V_SAVE, td, 0, 0);
330 	VOP_UNLOCK(devvp, 0, td);
331 	if (error)
332 		return (error);
333 
334 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
335 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
336 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, NULL, td);
337 	VOP_UNLOCK(devvp, 0, td);
338 	if (error)
339 		return (error);
340 	dev = devvp->v_rdev;
341 	bp  = NULL; /* both used in error_exit */
342 	pmp = NULL;
343 
344 #ifndef __DragonFly__
345 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
346 		/*
347 	 	 * We need the disklabel to calculate the size of a FAT entry
348 		 * later on. Also make sure the partition contains a filesystem
349 		 * of type FS_MSDOS. This doesn't work for floppies, so we have
350 		 * to check for them too.
351 	 	 *
352 	 	 * At least some parts of the msdos fs driver seem to assume
353 		 * that the size of a disk block will always be 512 bytes.
354 		 * Let's check it...
355 		 */
356 		error = VOP_IOCTL(devvp, DIOCGPART, (caddr_t)&dpart, FREAD, td);
357 		if (error)
358 			goto error_exit;
359 		tmp   = dpart.part->p_fstype;
360 		dtype = dpart.disklab->d_type;
361 		bsize = dpart.disklab->d_secsize;
362 		if (bsize != 512 || (dtype!=DTYPE_FLOPPY && tmp!=FS_MSDOS)) {
363 			error = EINVAL;
364 			goto error_exit;
365 		}
366 	}
367 #endif
368 
369 	/*
370 	 * Read the boot sector of the filesystem, and then check the
371 	 * boot signature.  If not a dos boot sector then error out.
372 	 *
373 	 * NOTE: 2048 is a maximum sector size in current...
374 	 */
375 	error = bread(devvp, 0, 2048, &bp);
376 	if (error)
377 		goto error_exit;
378 	bp->b_flags |= B_AGE;
379 	bsp = (union bootsector *)bp->b_data;
380 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
381 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
382 	b710 = (struct byte_bpb710 *)bsp->bs710.bsPBP;
383 
384 #ifndef __DragonFly__
385 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
386 #endif
387 #ifndef MSDOSFS_NOCHECKSIG
388 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
389 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
390 			error = EINVAL;
391 			goto error_exit;
392 		}
393 #endif
394 #ifndef __DragonFly__
395 	}
396 #endif
397 
398 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK);
399 	bzero((caddr_t)pmp, sizeof *pmp);
400 	pmp->pm_mountp = mp;
401 
402 	/*
403 	 * Compute several useful quantities from the bpb in the
404 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
405 	 * the fields that are different between dos 5 and dos 3.3.
406 	 */
407 	SecPerClust = b50->bpbSecPerClust;
408 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
409 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
410 	pmp->pm_FATs = b50->bpbFATs;
411 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
412 	pmp->pm_Sectors = getushort(b50->bpbSectors);
413 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
414 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
415 	pmp->pm_Heads = getushort(b50->bpbHeads);
416 	pmp->pm_Media = b50->bpbMedia;
417 
418 	/* calculate the ratio of sector size to DEV_BSIZE */
419 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
420 
421 #ifndef __DragonFly__
422 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
423 #endif
424 		/* XXX - We should probably check more values here */
425 		if (!pmp->pm_BytesPerSec || !SecPerClust
426 			|| !pmp->pm_Heads
427 			|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
428 			error = EINVAL;
429 			goto error_exit;
430 		}
431 #ifndef __DragonFly__
432 	}
433 #endif
434 
435 	if (pmp->pm_Sectors == 0) {
436 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
437 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
438 	} else {
439 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
440 		pmp->pm_HugeSectors = pmp->pm_Sectors;
441 	}
442 	if (pmp->pm_HugeSectors > 0xffffffff /
443 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
444 		/*
445 		 * We cannot deal currently with this size of disk
446 		 * due to fileid limitations (see msdosfs_getattr and
447 		 * msdosfs_readdir)
448 		 */
449 		error = EINVAL;
450 		printf("mountmsdosfs(): disk too big, sorry\n");
451 		goto error_exit;
452 	}
453 
454 	if (pmp->pm_RootDirEnts == 0) {
455 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
456 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
457 		    || pmp->pm_Sectors
458 		    || pmp->pm_FATsecs
459 		    || getushort(b710->bpbFSVers)) {
460 			error = EINVAL;
461 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
462 			goto error_exit;
463 		}
464 		pmp->pm_fatmask = FAT32_MASK;
465 		pmp->pm_fatmult = 4;
466 		pmp->pm_fatdiv = 1;
467 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
468 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
469 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
470 		else
471 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
472 	} else
473 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
474 
475 	/*
476 	 * Check a few values (could do some more):
477 	 * - logical sector size: power of 2, >= block size
478 	 * - sectors per cluster: power of 2, >= 1
479 	 * - number of sectors:   >= 1, <= size of partition
480 	 */
481 	if ( (SecPerClust == 0)
482 	  || (SecPerClust & (SecPerClust - 1))
483 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
484 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
485 	  || (pmp->pm_HugeSectors == 0)
486 	) {
487 		error = EINVAL;
488 		goto error_exit;
489 	}
490 
491 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
492 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
493 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
494 	SecPerClust         *= pmp->pm_BlkPerSec;
495 
496 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
497 
498 	if (FAT32(pmp)) {
499 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
500 		pmp->pm_firstcluster = pmp->pm_fatblk
501 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
502 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
503 	} else {
504 		pmp->pm_rootdirblk = pmp->pm_fatblk +
505 			(pmp->pm_FATs * pmp->pm_FATsecs);
506 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
507 				       + DEV_BSIZE - 1)
508 			/ DEV_BSIZE; /* in blocks */
509 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
510 	}
511 
512 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
513 	    SecPerClust + 1;
514 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
515 
516 #ifndef __DragonFly__
517 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
518 		if ((pmp->pm_maxcluster <= (0xff0 - 2))
519 		      && ((dtype == DTYPE_FLOPPY) || ((dtype == DTYPE_VNODE)
520 		      && ((pmp->pm_Heads == 1) || (pmp->pm_Heads == 2))))
521 		    ) {
522 			pmp->pm_fatmask = FAT12_MASK;
523 			pmp->pm_fatmult = 3;
524 			pmp->pm_fatdiv = 2;
525 		} else {
526 			pmp->pm_fatmask = FAT16_MASK;
527 			pmp->pm_fatmult = 2;
528 			pmp->pm_fatdiv = 1;
529 		}
530 	} else
531 #endif
532 	if (pmp->pm_fatmask == 0) {
533 		if (pmp->pm_maxcluster
534 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
535 			/*
536 			 * This will usually be a floppy disk. This size makes
537 			 * sure that one fat entry will not be split across
538 			 * multiple blocks.
539 			 */
540 			pmp->pm_fatmask = FAT12_MASK;
541 			pmp->pm_fatmult = 3;
542 			pmp->pm_fatdiv = 2;
543 		} else {
544 			pmp->pm_fatmask = FAT16_MASK;
545 			pmp->pm_fatmult = 2;
546 			pmp->pm_fatdiv = 1;
547 		}
548 	}
549 
550 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
551 	if (pmp->pm_maxcluster >= clusters) {
552 		printf("Warning: number of clusters (%ld) exceeds FAT "
553 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
554 		pmp->pm_maxcluster = clusters - 1;
555 	}
556 
557 
558 	if (FAT12(pmp))
559 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
560 	else
561 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
562 
563 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
564 	pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
565 
566 	/*
567 	 * Compute mask and shift value for isolating cluster relative byte
568 	 * offsets and cluster numbers from a file offset.
569 	 */
570 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
571 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
572 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
573 
574 	/*
575 	 * Check for valid cluster size
576 	 * must be a power of 2
577 	 */
578 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
579 		error = EINVAL;
580 		goto error_exit;
581 	}
582 
583 	/*
584 	 * Release the bootsector buffer.
585 	 */
586 	brelse(bp);
587 	bp = NULL;
588 
589 	/*
590 	 * Check FSInfo.
591 	 */
592 	if (pmp->pm_fsinfo) {
593 		struct fsinfo *fp;
594 
595 		if ((error = bread(devvp, pmp->pm_fsinfo, fsi_size(pmp), &bp)) != 0)
596 			goto error_exit;
597 		fp = (struct fsinfo *)bp->b_data;
598 		if (!bcmp(fp->fsisig1, "RRaA", 4)
599 		    && !bcmp(fp->fsisig2, "rrAa", 4)
600 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
601 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4)) {
602 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
603 			if (pmp->pm_nxtfree == 0xffffffff)
604 				pmp->pm_nxtfree = CLUST_FIRST;
605 		} else
606 			pmp->pm_fsinfo = 0;
607 		brelse(bp);
608 		bp = NULL;
609 	}
610 
611 	/*
612 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
613 	 */
614 	if (pmp->pm_fsinfo && pmp->pm_nxtfree > pmp->pm_maxcluster) {
615 		printf(
616 		"Next free cluster in FSInfo (%lu) exceeds maxcluster (%lu)\n",
617 		    pmp->pm_nxtfree, pmp->pm_maxcluster);
618 		error = EINVAL;
619 		goto error_exit;
620 	}
621 
622 	/*
623 	 * Allocate memory for the bitmap of allocated clusters, and then
624 	 * fill it in.
625 	 */
626 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
627 				   / N_INUSEBITS)
628 				  * sizeof(*pmp->pm_inusemap),
629 				  M_MSDOSFSFAT, M_WAITOK);
630 
631 	/*
632 	 * fillinusemap() needs pm_devvp.
633 	 */
634 	pmp->pm_dev = dev;
635 	pmp->pm_devvp = devvp;
636 
637 	/*
638 	 * Have the inuse map filled in.
639 	 */
640 	if ((error = fillinusemap(pmp)) != 0)
641 		goto error_exit;
642 
643 	/*
644 	 * If they want fat updates to be synchronous then let them suffer
645 	 * the performance degradation in exchange for the on disk copy of
646 	 * the fat being correct just about all the time.  I suppose this
647 	 * would be a good thing to turn on if the kernel is still flakey.
648 	 */
649 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
650 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
651 
652 	/*
653 	 * Finish up.
654 	 */
655 	if (ronly)
656 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
657 	else
658 		pmp->pm_fmod = 1;
659 	mp->mnt_data = (qaddr_t) pmp;
660 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
661 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
662 	mp->mnt_flag |= MNT_LOCAL;
663 	vfs_add_vnodeops(mp, &mp->mnt_vn_norm_ops,
664 			 msdosfs_vnodeop_entries, 0);
665 	dev->si_mountpoint = mp;
666 
667 	return 0;
668 
669 error_exit:
670 	if (bp)
671 		brelse(bp);
672 	VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE, td);
673 	if (pmp) {
674 		if (pmp->pm_inusemap)
675 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
676 		free(pmp, M_MSDOSFSMNT);
677 		mp->mnt_data = (qaddr_t)0;
678 	}
679 	return (error);
680 }
681 
682 /*
683  * Unmount the filesystem described by mp.
684  */
685 static int
686 msdosfs_unmount(struct mount *mp, int mntflags, struct thread *td)
687 {
688 	struct msdosfsmount *pmp;
689 	int error, flags;
690 
691 	flags = 0;
692 	if (mntflags & MNT_FORCE)
693 		flags |= FORCECLOSE;
694 	error = vflush(mp, 0, flags);
695 	if (error)
696 		return error;
697 	pmp = VFSTOMSDOSFS(mp);
698 	pmp->pm_devvp->v_rdev->si_mountpoint = NULL;
699 #ifdef MSDOSFS_DEBUG
700 	{
701 		struct vnode *vp = pmp->pm_devvp;
702 
703 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
704 		printf("flag %08lx, usecount %d, writecount %d, holdcnt %ld\n",
705 		    vp->v_flag, vp->v_usecount, vp->v_writecount, vp->v_holdcnt);
706 		printf("id %lu, mount %p, op %p\n",
707 		    vp->v_id, vp->v_mount, vp->v_op);
708 		printf("freef %p, freeb %p, mount %p\n",
709 		    TAILQ_NEXT(vp, v_freelist), TAILQ_PREV(vp, v_freelist),
710 		    vp->v_mount);
711 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
712 		    RB_EMPTY(&vp->v_rbclean_tree),
713 		    RB_EMPTY(&vp->v_rbdirty_tree),
714 		    vp->v_track_write.bk_active, vp->v_type);
715 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
716 		    vp->v_socket, vp->v_tag,
717 		    ((u_int *)vp->v_data)[0],
718 		    ((u_int *)vp->v_data)[1]);
719 	}
720 #endif
721 	error = VOP_CLOSE(pmp->pm_devvp,
722 		    (pmp->pm_flags&MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE,
723 		    td);
724 	vrele(pmp->pm_devvp);
725 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
726 	free(pmp, M_MSDOSFSMNT);
727 	mp->mnt_data = (qaddr_t)0;
728 	mp->mnt_flag &= ~MNT_LOCAL;
729 	return (error);
730 }
731 
732 static int
733 msdosfs_root(struct mount *mp, struct vnode **vpp)
734 {
735 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
736 	struct denode *ndep;
737 	int error;
738 
739 #ifdef MSDOSFS_DEBUG
740 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
741 #endif
742 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
743 	if (error)
744 		return (error);
745 	*vpp = DETOV(ndep);
746 	return (0);
747 }
748 
749 static int
750 msdosfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
751 {
752 	struct msdosfsmount *pmp;
753 
754 	pmp = VFSTOMSDOSFS(mp);
755 	sbp->f_bsize = pmp->pm_bpcluster;
756 	sbp->f_iosize = pmp->pm_bpcluster;
757 	sbp->f_blocks = pmp->pm_maxcluster + 1;
758 	sbp->f_bfree = pmp->pm_freeclustercount;
759 	sbp->f_bavail = pmp->pm_freeclustercount;
760 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
761 	sbp->f_ffree = 0;	/* what to put in here? */
762 	if (sbp != &mp->mnt_stat) {
763 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
764 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
765 	}
766 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
767 	return (0);
768 }
769 
770 struct scaninfo {
771 	int rescan;
772 	int allerror;
773 	int waitfor;
774 	thread_t td;
775 };
776 
777 static int msdosfs_sync_scan(struct mount *mp, struct vnode *vp, void *data);
778 
779 static int
780 msdosfs_sync(struct mount *mp, int waitfor, struct thread *td)
781 {
782 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
783 	struct scaninfo scaninfo;
784 	int error;
785 
786 	/*
787 	 * If we ever switch to not updating all of the fats all the time,
788 	 * this would be the place to update them from the first one.
789 	 */
790 	if (pmp->pm_fmod != 0) {
791 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
792 			panic("msdosfs_sync: rofs mod");
793 		else {
794 			/* update fats here */
795 		}
796 	}
797 	/*
798 	 * Write back each (modified) denode.
799 	 */
800 	scaninfo.allerror = 0;
801 	scaninfo.rescan = 1;
802 	scaninfo.td = td;
803 	while (scaninfo.rescan) {
804 		scaninfo.rescan = 0;
805 		vmntvnodescan(mp, VMSC_GETVP|VMSC_NOWAIT, NULL, msdosfs_sync_scan, &scaninfo);
806 	}
807 
808 	/*
809 	 * Flush filesystem control info.
810 	 */
811 	if (waitfor != MNT_LAZY) {
812 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY, td);
813 		if ((error = VOP_FSYNC(pmp->pm_devvp, waitfor, td)) != 0)
814 			scaninfo.allerror = error;
815 		VOP_UNLOCK(pmp->pm_devvp, 0, td);
816 	}
817 	return (scaninfo.allerror);
818 }
819 
820 static int
821 msdosfs_sync_scan(struct mount *mp, struct vnode *vp, void *data)
822 {
823 	struct scaninfo *info = data;
824 	struct denode *dep;
825 	int error;
826 
827 	dep = VTODE(vp);
828 	if (vp->v_type == VNON ||
829 	    ((dep->de_flag &
830 	    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
831 	    (RB_EMPTY(&vp->v_rbdirty_tree) || info->waitfor == MNT_LAZY))) {
832 		return(0);
833 	}
834 	if ((error = VOP_FSYNC(vp, info->waitfor, info->td)) != 0)
835 		info->allerror = error;
836 	return(0);
837 }
838 
839 static int
840 msdosfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
841 {
842 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
843 	struct defid *defhp = (struct defid *) fhp;
844 	struct denode *dep;
845 	int error;
846 
847 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
848 	if (error) {
849 		*vpp = NULLVP;
850 		return (error);
851 	}
852 	*vpp = DETOV(dep);
853 	return (0);
854 }
855 
856 static int
857 msdosfs_checkexp(struct mount *mp, struct sockaddr *nam, int *exflagsp,
858 		 struct ucred **credanonp)
859 {
860 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
861 	struct netcred *np;
862 
863 	np = vfs_export_lookup(mp, &pmp->pm_export, nam);
864 	if (np == NULL)
865 		return (EACCES);
866 	*exflagsp = np->netc_exflags;
867 	*credanonp = &np->netc_anon;
868 	return (0);
869 }
870 
871 static int
872 msdosfs_vptofh(struct vnode *vp, struct fid *fhp)
873 {
874 	struct denode *dep;
875 	struct defid *defhp;
876 
877 	dep = VTODE(vp);
878 	defhp = (struct defid *)fhp;
879 	defhp->defid_len = sizeof(struct defid);
880 	defhp->defid_dirclust = dep->de_dirclust;
881 	defhp->defid_dirofs = dep->de_diroffset;
882 	/* defhp->defid_gen = dep->de_gen; */
883 	return (0);
884 }
885 
886 static struct vfsops msdosfs_vfsops = {
887 	.vfs_mount =     	msdosfs_mount,
888 	.vfs_unmount =   	msdosfs_unmount,
889 	.vfs_root =     	msdosfs_root,
890 	.vfs_statfs =   	msdosfs_statfs,
891 	.vfs_sync =     	msdosfs_sync,
892 	.vfs_fhtovp =   	msdosfs_fhtovp,
893 	.vfs_checkexp =  	msdosfs_checkexp,
894 	.vfs_vptofh =   	msdosfs_vptofh,
895 	.vfs_init =     	msdosfs_init,
896 	.vfs_uninit =   	msdosfs_uninit
897 };
898 
899 VFS_SET(msdosfs_vfsops, msdos, 0);
900