xref: /dragonfly/sys/vfs/msdosfs/msdosfs_vfsops.c (revision 1ab20d67)
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 1.15 2004/05/19 22:53:05 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/namei.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 #define MSDOSFS_DFLTBSIZE       4096
74 
75 #if 1 /*def PC98*/
76 /*
77  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
78  *       garbage or a random value :-{
79  *       If you want to use that broken-signatured media, define the
80  *       following symbol even though PC/AT.
81  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
82  */
83 #define	MSDOSFS_NOCHECKSIG
84 #endif
85 
86 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOSFS mount structure");
87 static MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOSFS file allocation table");
88 
89 static int	update_mp (struct mount *mp, struct msdosfs_args *argp);
90 static int	mountmsdosfs (struct vnode *devvp, struct mount *mp,
91 				  struct thread *td, struct msdosfs_args *argp);
92 static int	msdosfs_fhtovp (struct mount *, struct fid *,
93 				    struct vnode **);
94 static int	msdosfs_checkexp (struct mount *, struct sockaddr *,
95 				    int *, struct ucred **);
96 static int	msdosfs_mount (struct mount *, char *, caddr_t,
97 				   struct nameidata *, struct thread *);
98 static int	msdosfs_root (struct mount *, struct vnode **);
99 static int	msdosfs_statfs (struct mount *, struct statfs *,
100 				    struct thread *);
101 static int	msdosfs_sync (struct mount *, int, struct thread *);
102 static int	msdosfs_unmount (struct mount *, int, struct thread *);
103 static int	msdosfs_vptofh (struct vnode *, struct fid *);
104 
105 static int
106 update_mp(struct mount *mp, struct msdosfs_args *argp)
107 {
108 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
109 	int error;
110 
111 	pmp->pm_gid = argp->gid;
112 	pmp->pm_uid = argp->uid;
113 	pmp->pm_mask = argp->mask & ALLPERMS;
114 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
115 	if (pmp->pm_flags & MSDOSFSMNT_U2WTABLE) {
116 		bcopy(argp->u2w, pmp->pm_u2w, sizeof(pmp->pm_u2w));
117 		bcopy(argp->d2u, pmp->pm_d2u, sizeof(pmp->pm_d2u));
118 		bcopy(argp->u2d, pmp->pm_u2d, sizeof(pmp->pm_u2d));
119 	}
120 	if (pmp->pm_flags & MSDOSFSMNT_ULTABLE) {
121 		bcopy(argp->ul, pmp->pm_ul, sizeof(pmp->pm_ul));
122 		bcopy(argp->lu, pmp->pm_lu, sizeof(pmp->pm_lu));
123 	}
124 
125 #ifndef __DragonFly__
126 	/*
127 	 * GEMDOS knows nothing (yet) about win95
128 	 */
129 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
130 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
131 #endif
132 
133 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
134 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
135 	else if (!(pmp->pm_flags &
136 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
137 		struct vnode *rootvp;
138 
139 		/*
140 		 * Try to divine whether to support Win'95 long filenames
141 		 */
142 		if (FAT32(pmp))
143 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
144 		else {
145 			if ((error = msdosfs_root(mp, &rootvp)) != 0)
146 				return error;
147 			pmp->pm_flags |= findwin95(VTODE(rootvp))
148 				? MSDOSFSMNT_LONGNAME
149 					: MSDOSFSMNT_SHORTNAME;
150 			vput(rootvp);
151 		}
152 	}
153 	return 0;
154 }
155 
156 #ifndef __DragonFly__
157 int
158 msdosfs_mountroot(void)
159 {
160 	struct mount *mp;
161 	struct thread *td = curthread;	/* XXX */
162 	size_t size;
163 	int error;
164 	struct msdosfs_args args;
165 
166 	if (root_device->dv_class != DV_DISK)
167 		return (ENODEV);
168 
169 	/*
170 	 * Get vnodes for swapdev and rootdev.
171 	 */
172 	if (bdevvp(rootdev, &rootvp))
173 		panic("msdosfs_mountroot: can't setup rootvp");
174 
175 	mp = malloc((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK);
176 	bzero((char *)mp, (u_long)sizeof(struct mount));
177 	mp->mnt_op = &msdosfs_vfsops;
178 	mp->mnt_flag = 0;
179 	TAILQ_INIT(&mp->mnt_nvnodelist);
180 	TAILQ_INIT(&mp->mnt_reservedvnlist);
181 
182 	args.flags = 0;
183 	args.uid = 0;
184 	args.gid = 0;
185 	args.mask = 0777;
186 
187 	if ((error = mountmsdosfs(rootvp, mp, p, &args)) != 0) {
188 		free(mp, M_MOUNT);
189 		return (error);
190 	}
191 
192 	if ((error = update_mp(mp, &args)) != 0) {
193 		(void)msdosfs_unmount(mp, 0, p);
194 		free(mp, M_MOUNT);
195 		return (error);
196 	}
197 
198 	if ((error = vfs_lock(mp)) != 0) {
199 		(void)msdosfs_unmount(mp, 0, p);
200 		free(mp, M_MOUNT);
201 		return (error);
202 	}
203 
204 	TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
205 	mp->mnt_vnodecovered = NULLVP;
206 	(void) copystr("/", mp->mnt_stat.f_mntonname, MNAMELEN - 1,
207 	    &size);
208 	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
209 	(void) copystr(ROOTNAME, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
210 	    &size);
211 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
212 	(void)msdosfs_statfs(mp, &mp->mnt_stat, p);
213 	vfs_unlock(mp);
214 	return (0);
215 }
216 #endif
217 
218 /*
219  * mp - path - addr in user space of mount point (ie /usr or whatever)
220  * data - addr in user space of mount params including the name of the block
221  * special file to treat as a filesystem.
222  */
223 static int
224 msdosfs_mount(struct mount *mp, char *path, caddr_t data, struct nameidata *ndp,
225 	      struct thread *td)
226 {
227 	struct vnode *devvp;	  /* vnode for blk device to mount */
228 	struct msdosfs_args args; /* will hold data from mount request */
229 	/* msdosfs specific mount control block */
230 	struct msdosfsmount *pmp = NULL;
231 	size_t size;
232 	int error, flags;
233 	mode_t accessmode;
234 	struct proc *p = td->td_proc;
235 
236 	KKASSERT(p);
237 
238 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
239 	if (error)
240 		return (error);
241 	if (args.magic != MSDOSFS_ARGSMAGIC)
242 		args.flags = 0;
243 	/*
244 	 * If updating, check whether changing from read-only to
245 	 * read/write; if there is no device name, that's all we do.
246 	 */
247 	if (mp->mnt_flag & MNT_UPDATE) {
248 		pmp = VFSTOMSDOSFS(mp);
249 		error = 0;
250 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
251 			flags = WRITECLOSE;
252 			if (mp->mnt_flag & MNT_FORCE)
253 				flags |= FORCECLOSE;
254 			error = vflush(mp, 0, flags);
255 		}
256 		if (!error && (mp->mnt_flag & MNT_RELOAD))
257 			/* not yet implemented */
258 			error = EOPNOTSUPP;
259 		if (error)
260 			return (error);
261 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
262 			/*
263 			 * If upgrade to read-write by non-root, then verify
264 			 * that user has necessary permissions on the device.
265 			 */
266 			if (p->p_ucred->cr_uid != 0) {
267 				devvp = pmp->pm_devvp;
268 				vn_lock(devvp, NULL, LK_EXCLUSIVE | LK_RETRY, td);
269 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
270 						   p->p_ucred, td);
271 				if (error) {
272 					VOP_UNLOCK(devvp, NULL, 0, td);
273 					return (error);
274 				}
275 				VOP_UNLOCK(devvp, NULL, 0, td);
276 			}
277 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
278 		}
279 		if (args.fspec == 0) {
280 #ifdef	__notyet__		/* doesn't work correctly with current mountd	XXX */
281 			if (args.flags & MSDOSFSMNT_MNTOPT) {
282 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
283 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
284 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
285 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
286 			}
287 #endif
288 			/*
289 			 * Process export requests.
290 			 */
291 			return (vfs_export(mp, &pmp->pm_export, &args.export));
292 		}
293 	}
294 	/*
295 	 * Not an update, or updating the name: look up the name
296 	 * and verify that it refers to a sensible block device.
297 	 */
298 	NDINIT(ndp, NAMEI_LOOKUP, CNP_FOLLOW, UIO_USERSPACE, args.fspec, td);
299 	error = namei(ndp);
300 	if (error)
301 		return (error);
302 	devvp = ndp->ni_vp;
303 	NDFREE(ndp, NDF_ONLY_PNBUF);
304 
305 	if (!vn_isdisk(devvp, &error)) {
306 		vrele(devvp);
307 		return (error);
308 	}
309 	/*
310 	 * If mount by non-root, then verify that user has necessary
311 	 * permissions on the device.
312 	 */
313 	if (p->p_ucred->cr_uid != 0) {
314 		accessmode = VREAD;
315 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
316 			accessmode |= VWRITE;
317 		vn_lock(devvp, NULL, LK_EXCLUSIVE | LK_RETRY, td);
318 		error = VOP_ACCESS(devvp, accessmode, p->p_ucred, td);
319 		if (error) {
320 			vput(devvp);
321 			return (error);
322 		}
323 		VOP_UNLOCK(devvp, NULL, 0, td);
324 	}
325 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
326 		error = mountmsdosfs(devvp, mp, td, &args);
327 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
328 		pmp = VFSTOMSDOSFS(mp);
329 #endif
330 	} else {
331 		if (devvp != pmp->pm_devvp)
332 			error = EINVAL;	/* XXX needs translation */
333 		else
334 			vrele(devvp);
335 	}
336 	if (error) {
337 		vrele(devvp);
338 		return (error);
339 	}
340 
341 	error = update_mp(mp, &args);
342 	if (error) {
343 		msdosfs_unmount(mp, MNT_FORCE, td);
344 		return error;
345 	}
346 
347 	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
348 	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
349 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
350 	    &size);
351 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
352 	(void) msdosfs_statfs(mp, &mp->mnt_stat, td);
353 #ifdef MSDOSFS_DEBUG
354 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
355 #endif
356 	return (0);
357 }
358 
359 static int
360 mountmsdosfs(struct vnode *devvp, struct mount *mp, struct thread *td,
361 	     struct msdosfs_args *argp)
362 {
363 	struct msdosfsmount *pmp;
364 	struct buf *bp;
365 	dev_t dev;
366 #ifndef __DragonFly__
367 	struct partinfo dpart;
368 	int bsize = 0, dtype = 0, tmp;
369 #endif
370 	union bootsector *bsp;
371 	struct byte_bpb33 *b33;
372 	struct byte_bpb50 *b50;
373 	struct byte_bpb710 *b710;
374 	u_int8_t SecPerClust;
375 	u_long clusters;
376 	int	ronly, error;
377 
378 	/*
379 	 * Disallow multiple mounts of the same device.
380 	 * Disallow mounting of a device that is currently in use
381 	 * (except for root, which might share swap device for miniroot).
382 	 * Flush out any old buffers remaining from a previous use.
383 	 */
384 	error = vfs_mountedon(devvp);
385 	if (error)
386 		return (error);
387 	if (count_udev(devvp) > 0 && devvp != rootvp)
388 		return (EBUSY);
389 	vn_lock(devvp, NULL, LK_EXCLUSIVE | LK_RETRY, td);
390 	error = vinvalbuf(devvp, V_SAVE, td, 0, 0);
391 	VOP_UNLOCK(devvp, NULL, 0, td);
392 	if (error)
393 		return (error);
394 
395 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
396 	vn_lock(devvp, NULL, LK_EXCLUSIVE | LK_RETRY, td);
397 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, td);
398 	VOP_UNLOCK(devvp, NULL, 0, td);
399 	if (error)
400 		return (error);
401 	dev = devvp->v_rdev;
402 	bp  = NULL; /* both used in error_exit */
403 	pmp = NULL;
404 
405 #ifndef __DragonFly__
406 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
407 		/*
408 	 	 * We need the disklabel to calculate the size of a FAT entry
409 		 * later on. Also make sure the partition contains a filesystem
410 		 * of type FS_MSDOS. This doesn't work for floppies, so we have
411 		 * to check for them too.
412 	 	 *
413 	 	 * At least some parts of the msdos fs driver seem to assume
414 		 * that the size of a disk block will always be 512 bytes.
415 		 * Let's check it...
416 		 */
417 		error = VOP_IOCTL(devvp, DIOCGPART, (caddr_t)&dpart, FREAD, td);
418 		if (error)
419 			goto error_exit;
420 		tmp   = dpart.part->p_fstype;
421 		dtype = dpart.disklab->d_type;
422 		bsize = dpart.disklab->d_secsize;
423 		if (bsize != 512 || (dtype!=DTYPE_FLOPPY && tmp!=FS_MSDOS)) {
424 			error = EINVAL;
425 			goto error_exit;
426 		}
427 	}
428 #endif
429 
430 	/*
431 	 * Read the boot sector of the filesystem, and then check the
432 	 * boot signature.  If not a dos boot sector then error out.
433 	 *
434 	 * NOTE: 2048 is a maximum sector size in current...
435 	 */
436 	error = bread(devvp, 0, 2048, &bp);
437 	if (error)
438 		goto error_exit;
439 	bp->b_flags |= B_AGE;
440 	bsp = (union bootsector *)bp->b_data;
441 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
442 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
443 	b710 = (struct byte_bpb710 *)bsp->bs710.bsPBP;
444 
445 #ifndef __DragonFly__
446 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
447 #endif
448 #ifndef MSDOSFS_NOCHECKSIG
449 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
450 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
451 			error = EINVAL;
452 			goto error_exit;
453 		}
454 #endif
455 #ifndef __DragonFly__
456 	}
457 #endif
458 
459 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK);
460 	bzero((caddr_t)pmp, sizeof *pmp);
461 	pmp->pm_mountp = mp;
462 
463 	/*
464 	 * Compute several useful quantities from the bpb in the
465 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
466 	 * the fields that are different between dos 5 and dos 3.3.
467 	 */
468 	SecPerClust = b50->bpbSecPerClust;
469 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
470 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
471 	pmp->pm_FATs = b50->bpbFATs;
472 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
473 	pmp->pm_Sectors = getushort(b50->bpbSectors);
474 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
475 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
476 	pmp->pm_Heads = getushort(b50->bpbHeads);
477 	pmp->pm_Media = b50->bpbMedia;
478 
479 	/* calculate the ratio of sector size to DEV_BSIZE */
480 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
481 
482 #ifndef __DragonFly__
483 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
484 #endif
485 		/* XXX - We should probably check more values here */
486 		if (!pmp->pm_BytesPerSec || !SecPerClust
487 			|| !pmp->pm_Heads
488 #ifdef PC98
489 	    		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) {
490 #else
491 			|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
492 #endif
493 			error = EINVAL;
494 			goto error_exit;
495 		}
496 #ifndef __DragonFly__
497 	}
498 #endif
499 
500 	if (pmp->pm_Sectors == 0) {
501 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
502 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
503 	} else {
504 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
505 		pmp->pm_HugeSectors = pmp->pm_Sectors;
506 	}
507 	if (pmp->pm_HugeSectors > 0xffffffff /
508 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
509 		/*
510 		 * We cannot deal currently with this size of disk
511 		 * due to fileid limitations (see msdosfs_getattr and
512 		 * msdosfs_readdir)
513 		 */
514 		error = EINVAL;
515 		printf("mountmsdosfs(): disk too big, sorry\n");
516 		goto error_exit;
517 	}
518 
519 	if (pmp->pm_RootDirEnts == 0) {
520 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
521 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
522 		    || pmp->pm_Sectors
523 		    || pmp->pm_FATsecs
524 		    || getushort(b710->bpbFSVers)) {
525 			error = EINVAL;
526 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
527 			goto error_exit;
528 		}
529 		pmp->pm_fatmask = FAT32_MASK;
530 		pmp->pm_fatmult = 4;
531 		pmp->pm_fatdiv = 1;
532 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
533 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
534 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
535 		else
536 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
537 	} else
538 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
539 
540 	/*
541 	 * Check a few values (could do some more):
542 	 * - logical sector size: power of 2, >= block size
543 	 * - sectors per cluster: power of 2, >= 1
544 	 * - number of sectors:   >= 1, <= size of partition
545 	 */
546 	if ( (SecPerClust == 0)
547 	  || (SecPerClust & (SecPerClust - 1))
548 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
549 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
550 	  || (pmp->pm_HugeSectors == 0)
551 	) {
552 		error = EINVAL;
553 		goto error_exit;
554 	}
555 
556 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
557 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
558 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
559 	SecPerClust         *= pmp->pm_BlkPerSec;
560 
561 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
562 
563 	if (FAT32(pmp)) {
564 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
565 		pmp->pm_firstcluster = pmp->pm_fatblk
566 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
567 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
568 	} else {
569 		pmp->pm_rootdirblk = pmp->pm_fatblk +
570 			(pmp->pm_FATs * pmp->pm_FATsecs);
571 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
572 				       + DEV_BSIZE - 1)
573 			/ DEV_BSIZE; /* in blocks */
574 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
575 	}
576 
577 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
578 	    SecPerClust + 1;
579 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
580 
581 #ifndef __DragonFly__
582 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
583 		if ((pmp->pm_maxcluster <= (0xff0 - 2))
584 		      && ((dtype == DTYPE_FLOPPY) || ((dtype == DTYPE_VNODE)
585 		      && ((pmp->pm_Heads == 1) || (pmp->pm_Heads == 2))))
586 		    ) {
587 			pmp->pm_fatmask = FAT12_MASK;
588 			pmp->pm_fatmult = 3;
589 			pmp->pm_fatdiv = 2;
590 		} else {
591 			pmp->pm_fatmask = FAT16_MASK;
592 			pmp->pm_fatmult = 2;
593 			pmp->pm_fatdiv = 1;
594 		}
595 	} else
596 #endif
597 	if (pmp->pm_fatmask == 0) {
598 		if (pmp->pm_maxcluster
599 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
600 			/*
601 			 * This will usually be a floppy disk. This size makes
602 			 * sure that one fat entry will not be split across
603 			 * multiple blocks.
604 			 */
605 			pmp->pm_fatmask = FAT12_MASK;
606 			pmp->pm_fatmult = 3;
607 			pmp->pm_fatdiv = 2;
608 		} else {
609 			pmp->pm_fatmask = FAT16_MASK;
610 			pmp->pm_fatmult = 2;
611 			pmp->pm_fatdiv = 1;
612 		}
613 	}
614 
615 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
616 	if (pmp->pm_maxcluster >= clusters) {
617 		printf("Warning: number of clusters (%ld) exceeds FAT "
618 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
619 		pmp->pm_maxcluster = clusters - 1;
620 	}
621 
622 
623 	if (FAT12(pmp))
624 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
625 	else
626 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
627 
628 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
629 	pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
630 
631 	/*
632 	 * Compute mask and shift value for isolating cluster relative byte
633 	 * offsets and cluster numbers from a file offset.
634 	 */
635 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
636 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
637 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
638 
639 	/*
640 	 * Check for valid cluster size
641 	 * must be a power of 2
642 	 */
643 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
644 		error = EINVAL;
645 		goto error_exit;
646 	}
647 
648 	/*
649 	 * Release the bootsector buffer.
650 	 */
651 	brelse(bp);
652 	bp = NULL;
653 
654 	/*
655 	 * Check FSInfo.
656 	 */
657 	if (pmp->pm_fsinfo) {
658 		struct fsinfo *fp;
659 
660 		if ((error = bread(devvp, pmp->pm_fsinfo, fsi_size(pmp), &bp)) != 0)
661 			goto error_exit;
662 		fp = (struct fsinfo *)bp->b_data;
663 		if (!bcmp(fp->fsisig1, "RRaA", 4)
664 		    && !bcmp(fp->fsisig2, "rrAa", 4)
665 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
666 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4)) {
667 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
668 			if (pmp->pm_nxtfree == 0xffffffff)
669 				pmp->pm_nxtfree = CLUST_FIRST;
670 		} else
671 			pmp->pm_fsinfo = 0;
672 		brelse(bp);
673 		bp = NULL;
674 	}
675 
676 	/*
677 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
678 	 */
679 	if (pmp->pm_fsinfo && pmp->pm_nxtfree > pmp->pm_maxcluster) {
680 		printf(
681 		"Next free cluster in FSInfo (%lu) exceeds maxcluster (%lu)\n",
682 		    pmp->pm_nxtfree, pmp->pm_maxcluster);
683 		error = EINVAL;
684 		goto error_exit;
685 	}
686 
687 	/*
688 	 * Allocate memory for the bitmap of allocated clusters, and then
689 	 * fill it in.
690 	 */
691 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
692 				   / N_INUSEBITS)
693 				  * sizeof(*pmp->pm_inusemap),
694 				  M_MSDOSFSFAT, M_WAITOK);
695 
696 	/*
697 	 * fillinusemap() needs pm_devvp.
698 	 */
699 	pmp->pm_dev = dev;
700 	pmp->pm_devvp = devvp;
701 
702 	/*
703 	 * Have the inuse map filled in.
704 	 */
705 	if ((error = fillinusemap(pmp)) != 0)
706 		goto error_exit;
707 
708 	/*
709 	 * If they want fat updates to be synchronous then let them suffer
710 	 * the performance degradation in exchange for the on disk copy of
711 	 * the fat being correct just about all the time.  I suppose this
712 	 * would be a good thing to turn on if the kernel is still flakey.
713 	 */
714 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
715 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
716 
717 	/*
718 	 * Finish up.
719 	 */
720 	if (ronly)
721 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
722 	else
723 		pmp->pm_fmod = 1;
724 	mp->mnt_data = (qaddr_t) pmp;
725 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
726 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
727 	mp->mnt_flag |= MNT_LOCAL;
728 	dev->si_mountpoint = mp;
729 
730 	return 0;
731 
732 error_exit:
733 	if (bp)
734 		brelse(bp);
735 	(void) VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE, td);
736 	if (pmp) {
737 		if (pmp->pm_inusemap)
738 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
739 		free(pmp, M_MSDOSFSMNT);
740 		mp->mnt_data = (qaddr_t)0;
741 	}
742 	return (error);
743 }
744 
745 /*
746  * Unmount the filesystem described by mp.
747  */
748 static int
749 msdosfs_unmount(struct mount *mp, int mntflags, struct thread *td)
750 {
751 	struct msdosfsmount *pmp;
752 	int error, flags;
753 
754 	flags = 0;
755 	if (mntflags & MNT_FORCE)
756 		flags |= FORCECLOSE;
757 	error = vflush(mp, 0, flags);
758 	if (error)
759 		return error;
760 	pmp = VFSTOMSDOSFS(mp);
761 	pmp->pm_devvp->v_rdev->si_mountpoint = NULL;
762 #ifdef MSDOSFS_DEBUG
763 	{
764 		struct vnode *vp = pmp->pm_devvp;
765 
766 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
767 		printf("flag %08lx, usecount %d, writecount %d, holdcnt %ld\n",
768 		    vp->v_flag, vp->v_usecount, vp->v_writecount, vp->v_holdcnt);
769 		printf("id %lu, mount %p, op %p\n",
770 		    vp->v_id, vp->v_mount, vp->v_op);
771 		printf("freef %p, freeb %p, mount %p\n",
772 		    vp->v_freelist.tqe_next, vp->v_freelist.tqe_prev,
773 		    vp->v_mount);
774 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
775 		    TAILQ_FIRST(&vp->v_cleanblkhd),
776 		    TAILQ_FIRST(&vp->v_dirtyblkhd),
777 		    vp->v_numoutput, vp->v_type);
778 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
779 		    vp->v_socket, vp->v_tag,
780 		    ((u_int *)vp->v_data)[0],
781 		    ((u_int *)vp->v_data)[1]);
782 	}
783 #endif
784 	error = VOP_CLOSE(pmp->pm_devvp,
785 		    (pmp->pm_flags&MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE,
786 		    td);
787 	vrele(pmp->pm_devvp);
788 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
789 	free(pmp, M_MSDOSFSMNT);
790 	mp->mnt_data = (qaddr_t)0;
791 	mp->mnt_flag &= ~MNT_LOCAL;
792 	return (error);
793 }
794 
795 static int
796 msdosfs_root(struct mount *mp, struct vnode **vpp)
797 {
798 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
799 	struct denode *ndep;
800 	int error;
801 
802 #ifdef MSDOSFS_DEBUG
803 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
804 #endif
805 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
806 	if (error)
807 		return (error);
808 	*vpp = DETOV(ndep);
809 	return (0);
810 }
811 
812 static int
813 msdosfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
814 {
815 	struct msdosfsmount *pmp;
816 
817 	pmp = VFSTOMSDOSFS(mp);
818 	sbp->f_bsize = pmp->pm_bpcluster;
819 	sbp->f_iosize = pmp->pm_bpcluster;
820 	sbp->f_blocks = pmp->pm_maxcluster + 1;
821 	sbp->f_bfree = pmp->pm_freeclustercount;
822 	sbp->f_bavail = pmp->pm_freeclustercount;
823 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
824 	sbp->f_ffree = 0;	/* what to put in here? */
825 	if (sbp != &mp->mnt_stat) {
826 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
827 		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
828 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
829 	}
830 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
831 	return (0);
832 }
833 
834 struct scaninfo {
835 	int rescan;
836 	int allerror;
837 	int waitfor;
838 	thread_t td;
839 };
840 
841 static int msdosfs_sync_scan(struct mount *mp, struct vnode *vp,
842 		lwkt_tokref_t vlock, void *data);
843 
844 static int
845 msdosfs_sync(struct mount *mp, int waitfor, struct thread *td)
846 {
847 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
848 	struct scaninfo scaninfo;
849 	int error;
850 
851 	/*
852 	 * If we ever switch to not updating all of the fats all the time,
853 	 * this would be the place to update them from the first one.
854 	 */
855 	if (pmp->pm_fmod != 0) {
856 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
857 			panic("msdosfs_sync: rofs mod");
858 		else {
859 			/* update fats here */
860 		}
861 	}
862 	/*
863 	 * Write back each (modified) denode.
864 	 */
865 	scaninfo.allerror = 0;
866 	scaninfo.rescan = 1;
867 	scaninfo.td = td;
868 	while (scaninfo.rescan) {
869 		scaninfo.rescan = 0;
870 		vmntvnodescan(mp, NULL, msdosfs_sync_scan, &scaninfo);
871 	}
872 
873 	/*
874 	 * Flush filesystem control info.
875 	 */
876 	if (waitfor != MNT_LAZY) {
877 		vn_lock(pmp->pm_devvp, NULL, LK_EXCLUSIVE | LK_RETRY, td);
878 		if ((error = VOP_FSYNC(pmp->pm_devvp, waitfor, td)) != 0)
879 			scaninfo.allerror = error;
880 		VOP_UNLOCK(pmp->pm_devvp, NULL, 0, td);
881 	}
882 	return (scaninfo.allerror);
883 }
884 
885 static int
886 msdosfs_sync_scan(struct mount *mp, struct vnode *vp,
887 		  lwkt_tokref_t vlock, void *data)
888 {
889 	struct scaninfo *info = data;
890 	struct denode *dep;
891 	int error;
892 
893 	dep = VTODE(vp);
894 	if (vp->v_type == VNON ||
895 	    ((dep->de_flag &
896 	    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
897 	    (TAILQ_EMPTY(&vp->v_dirtyblkhd) || info->waitfor == MNT_LAZY))) {
898 		lwkt_reltoken(vlock);
899 		return(0);
900 	}
901 	error = vget(vp, vlock, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, info->td);
902 	if (error) {
903 		if (error == ENOENT)
904 			info->rescan = 1;
905 		return(0);
906 	}
907 	if ((error = VOP_FSYNC(vp, info->waitfor, info->td)) != 0)
908 		info->allerror = error;
909 	VOP_UNLOCK(vp, NULL, 0, info->td);
910 	vrele(vp);
911 	return(0);
912 }
913 
914 static int
915 msdosfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
916 {
917 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
918 	struct defid *defhp = (struct defid *) fhp;
919 	struct denode *dep;
920 	int error;
921 
922 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
923 	if (error) {
924 		*vpp = NULLVP;
925 		return (error);
926 	}
927 	*vpp = DETOV(dep);
928 	return (0);
929 }
930 
931 static int
932 msdosfs_checkexp(struct mount *mp, struct sockaddr *nam, int *exflagsp,
933 		 struct ucred **credanonp)
934 {
935 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
936 	struct netcred *np;
937 
938 	np = vfs_export_lookup(mp, &pmp->pm_export, nam);
939 	if (np == NULL)
940 		return (EACCES);
941 	*exflagsp = np->netc_exflags;
942 	*credanonp = &np->netc_anon;
943 	return (0);
944 }
945 
946 static int
947 msdosfs_vptofh(struct vnode *vp, struct fid *fhp)
948 {
949 	struct denode *dep;
950 	struct defid *defhp;
951 
952 	dep = VTODE(vp);
953 	defhp = (struct defid *)fhp;
954 	defhp->defid_len = sizeof(struct defid);
955 	defhp->defid_dirclust = dep->de_dirclust;
956 	defhp->defid_dirofs = dep->de_diroffset;
957 	/* defhp->defid_gen = dep->de_gen; */
958 	return (0);
959 }
960 
961 static struct vfsops msdosfs_vfsops = {
962 	msdosfs_mount,
963 	vfs_stdstart,
964 	msdosfs_unmount,
965 	msdosfs_root,
966 	vfs_stdquotactl,
967 	msdosfs_statfs,
968 	msdosfs_sync,
969 	vfs_stdvget,
970 	msdosfs_fhtovp,
971 	msdosfs_checkexp,
972 	msdosfs_vptofh,
973 	msdosfs_init,
974 	msdosfs_uninit,
975 	vfs_stdextattrctl,
976 };
977 
978 VFS_SET(msdosfs_vfsops, msdos, 0);
979