xref: /netbsd-src/sys/fs/msdosfs/msdosfs_vfsops.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: msdosfs_vfsops.c,v 1.20 2004/09/13 19:25:48 jdolecek Exp $	*/
2 
3 /*-
4  * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
5  * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
6  * All rights reserved.
7  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by TooLs GmbH.
20  * 4. The name of TooLs GmbH may not be used to endorse or promote products
21  *    derived from this software without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
28  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
29  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
30  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
31  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
32  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  */
34 /*
35  * Written by Paul Popelka (paulp@uts.amdahl.com)
36  *
37  * You can do anything you want with this software, just don't say you wrote
38  * it, and don't remove this notice.
39  *
40  * This software is provided "as is".
41  *
42  * The author supplies this software to be publicly redistributed on the
43  * understanding that the author is not responsible for the correct
44  * functioning of this software in any circumstances and is not liable for
45  * any damages caused by this software.
46  *
47  * October 1992
48  */
49 
50 #include <sys/cdefs.h>
51 __KERNEL_RCSID(0, "$NetBSD: msdosfs_vfsops.c,v 1.20 2004/09/13 19:25:48 jdolecek Exp $");
52 
53 #if defined(_KERNEL_OPT)
54 #include "opt_quota.h"
55 #include "opt_compat_netbsd.h"
56 #endif
57 
58 #include <sys/param.h>
59 #include <sys/systm.h>
60 #include <sys/sysctl.h>
61 #include <sys/namei.h>
62 #include <sys/proc.h>
63 #include <sys/kernel.h>
64 #include <sys/vnode.h>
65 #include <miscfs/specfs/specdev.h> /* XXX */	/* defines v_rdev */
66 #include <sys/mount.h>
67 #include <sys/buf.h>
68 #include <sys/file.h>
69 #include <sys/device.h>
70 #include <sys/disklabel.h>
71 #include <sys/ioctl.h>
72 #include <sys/malloc.h>
73 #include <sys/dirent.h>
74 #include <sys/stat.h>
75 #include <sys/conf.h>
76 
77 #include <fs/msdosfs/bpb.h>
78 #include <fs/msdosfs/bootsect.h>
79 #include <fs/msdosfs/direntry.h>
80 #include <fs/msdosfs/denode.h>
81 #include <fs/msdosfs/msdosfsmount.h>
82 #include <fs/msdosfs/fat.h>
83 
84 #define MSDOSFS_NAMEMAX(pmp) \
85 	(pmp)->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12
86 
87 int msdosfs_mountroot __P((void));
88 int msdosfs_mount __P((struct mount *, const char *, void *,
89     struct nameidata *, struct proc *));
90 int msdosfs_start __P((struct mount *, int, struct proc *));
91 int msdosfs_unmount __P((struct mount *, int, struct proc *));
92 int msdosfs_root __P((struct mount *, struct vnode **));
93 int msdosfs_quotactl __P((struct mount *, int, uid_t, void *, struct proc *));
94 int msdosfs_statvfs __P((struct mount *, struct statvfs *, struct proc *));
95 int msdosfs_sync __P((struct mount *, int, struct ucred *, struct proc *));
96 int msdosfs_vget __P((struct mount *, ino_t, struct vnode **));
97 int msdosfs_fhtovp __P((struct mount *, struct fid *, struct vnode **));
98 int msdosfs_checkexp __P((struct mount *, struct mbuf *, int *,
99     struct ucred **));
100 int msdosfs_vptofh __P((struct vnode *, struct fid *));
101 
102 int msdosfs_mountfs __P((struct vnode *, struct mount *, struct proc *,
103     struct msdosfs_args *));
104 
105 static int update_mp __P((struct mount *, struct msdosfs_args *));
106 
107 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOS FS mount structure");
108 MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS fat", "MSDOS FS fat table");
109 
110 #define ROOTNAME "root_device"
111 
112 extern const struct vnodeopv_desc msdosfs_vnodeop_opv_desc;
113 
114 const struct vnodeopv_desc * const msdosfs_vnodeopv_descs[] = {
115 	&msdosfs_vnodeop_opv_desc,
116 	NULL,
117 };
118 
119 struct vfsops msdosfs_vfsops = {
120 	MOUNT_MSDOS,
121 	msdosfs_mount,
122 	msdosfs_start,
123 	msdosfs_unmount,
124 	msdosfs_root,
125 	msdosfs_quotactl,
126 	msdosfs_statvfs,
127 	msdosfs_sync,
128 	msdosfs_vget,
129 	msdosfs_fhtovp,
130 	msdosfs_vptofh,
131 	msdosfs_init,
132 	msdosfs_reinit,
133 	msdosfs_done,
134 	NULL,
135 	msdosfs_mountroot,
136 	msdosfs_checkexp,
137 	(int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
138 	msdosfs_vnodeopv_descs,
139 };
140 
141 static int
142 update_mp(mp, argp)
143 	struct mount *mp;
144 	struct msdosfs_args *argp;
145 {
146 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
147 	int error;
148 
149 	pmp->pm_gid = argp->gid;
150 	pmp->pm_uid = argp->uid;
151 	pmp->pm_mask = argp->mask & ALLPERMS;
152 	pmp->pm_dirmask = argp->dirmask & ALLPERMS;
153 	pmp->pm_gmtoff = argp->gmtoff;
154 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
155 
156 	/*
157 	 * GEMDOS knows nothing (yet) about win95
158 	 */
159 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
160 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
161 
162 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
163 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
164 	else if (!(pmp->pm_flags &
165 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
166 		struct vnode *rootvp;
167 
168 		/*
169 		 * Try to divine whether to support Win'95 long filenames
170 		 */
171 		if (FAT32(pmp))
172 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
173 		else {
174 			if ((error = msdosfs_root(mp, &rootvp)) != 0)
175 				return error;
176 			pmp->pm_flags |= findwin95(VTODE(rootvp))
177 				? MSDOSFSMNT_LONGNAME
178 					: MSDOSFSMNT_SHORTNAME;
179 			vput(rootvp);
180 		}
181 	}
182 
183 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
184 
185 	return 0;
186 }
187 
188 int
189 msdosfs_mountroot()
190 {
191 	struct mount *mp;
192 	struct proc *p = curproc;	/* XXX */
193 	int error;
194 	struct msdosfs_args args;
195 
196 	if (root_device->dv_class != DV_DISK)
197 		return (ENODEV);
198 
199 	/*
200 	 * Get vnodes for swapdev and rootdev.
201 	 */
202 	if (bdevvp(rootdev, &rootvp))
203 		panic("msdosfs_mountroot: can't setup rootvp");
204 
205 	if ((error = vfs_rootmountalloc(MOUNT_MSDOS, "root_device", &mp))) {
206 		vrele(rootvp);
207 		return (error);
208 	}
209 
210 	args.flags = MSDOSFSMNT_VERSIONED;
211 	args.uid = 0;
212 	args.gid = 0;
213 	args.mask = 0777;
214 	args.version = MSDOSFSMNT_VERSION;
215 	args.dirmask = 0777;
216 
217 	if ((error = msdosfs_mountfs(rootvp, mp, p, &args)) != 0) {
218 		mp->mnt_op->vfs_refcount--;
219 		vfs_unbusy(mp);
220 		free(mp, M_MOUNT);
221 		vrele(rootvp);
222 		return (error);
223 	}
224 
225 	if ((error = update_mp(mp, &args)) != 0) {
226 		(void)msdosfs_unmount(mp, 0, p);
227 		vfs_unbusy(mp);
228 		free(mp, M_MOUNT);
229 		vrele(rootvp);
230 		return (error);
231 	}
232 
233 	simple_lock(&mountlist_slock);
234 	CIRCLEQ_INSERT_TAIL(&mountlist, mp, mnt_list);
235 	simple_unlock(&mountlist_slock);
236 	(void)msdosfs_statvfs(mp, &mp->mnt_stat, p);
237 	vfs_unbusy(mp);
238 	return (0);
239 }
240 
241 /*
242  * mp - path - addr in user space of mount point (ie /usr or whatever)
243  * data - addr in user space of mount params including the name of the block
244  * special file to treat as a filesystem.
245  */
246 int
247 msdosfs_mount(mp, path, data, ndp, p)
248 	struct mount *mp;
249 	const char *path;
250 	void *data;
251 	struct nameidata *ndp;
252 	struct proc *p;
253 {
254 	struct vnode *devvp;	  /* vnode for blk device to mount */
255 	struct msdosfs_args args; /* will hold data from mount request */
256 	/* msdosfs specific mount control block */
257 	struct msdosfsmount *pmp = NULL;
258 	int error, flags;
259 	mode_t accessmode;
260 
261 	if (mp->mnt_flag & MNT_GETARGS) {
262 		pmp = VFSTOMSDOSFS(mp);
263 		if (pmp == NULL)
264 			return EIO;
265 		args.fspec = NULL;
266 		args.uid = pmp->pm_uid;
267 		args.gid = pmp->pm_gid;
268 		args.mask = pmp->pm_mask;
269 		args.flags = pmp->pm_flags;
270 		args.version = MSDOSFSMNT_VERSION;
271 		args.dirmask = pmp->pm_dirmask;
272 		args.gmtoff = pmp->pm_gmtoff;
273 		vfs_showexport(mp, &args.export, &pmp->pm_export);
274 		return copyout(&args, data, sizeof(args));
275 	}
276 	error = copyin(data, &args, sizeof(struct msdosfs_args));
277 	if (error)
278 		return (error);
279 
280 	/*
281 	 * If not versioned (i.e. using old mount_msdos(8)), fill in
282 	 * the additional structure items with suitable defaults.
283 	 */
284 	if ((args.flags & MSDOSFSMNT_VERSIONED) == 0) {
285 		args.version = 1;
286 		args.dirmask = args.mask;
287 	}
288 
289 	/*
290 	 * Reset GMT offset for pre-v3 mount structure args.
291 	 */
292 	if (args.version < 3)
293 		args.gmtoff = 0;
294 
295 	/*
296 	 * If updating, check whether changing from read-only to
297 	 * read/write; if there is no device name, that's all we do.
298 	 */
299 	if (mp->mnt_flag & MNT_UPDATE) {
300 		pmp = VFSTOMSDOSFS(mp);
301 		error = 0;
302 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
303 			flags = WRITECLOSE;
304 			if (mp->mnt_flag & MNT_FORCE)
305 				flags |= FORCECLOSE;
306 			error = vflush(mp, NULLVP, flags);
307 		}
308 		if (!error && (mp->mnt_flag & MNT_RELOAD))
309 			/* not yet implemented */
310 			error = EOPNOTSUPP;
311 		if (error)
312 			return (error);
313 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_iflag & IMNT_WANTRDWR)) {
314 			/*
315 			 * If upgrade to read-write by non-root, then verify
316 			 * that user has necessary permissions on the device.
317 			 */
318 			if (p->p_ucred->cr_uid != 0) {
319 				devvp = pmp->pm_devvp;
320 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
321 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
322 						   p->p_ucred, p);
323 				VOP_UNLOCK(devvp, 0);
324 				if (error)
325 					return (error);
326 			}
327 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
328 		}
329 		if (args.fspec == 0) {
330 #ifdef	__notyet__		/* doesn't work correctly with current mountd	XXX */
331 			if (args.flags & MSDOSFSMNT_MNTOPT) {
332 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
333 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
334 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
335 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
336 			}
337 #endif
338 			/*
339 			 * Process export requests.
340 			 */
341 			return (vfs_export(mp, &pmp->pm_export, &args.export));
342 		}
343 	}
344 	/*
345 	 * Not an update, or updating the name: look up the name
346 	 * and verify that it refers to a sensible block device.
347 	 */
348 	NDINIT(ndp, LOOKUP, FOLLOW, UIO_USERSPACE, args.fspec, p);
349 	if ((error = namei(ndp)) != 0)
350 		return (error);
351 	devvp = ndp->ni_vp;
352 
353 	if (devvp->v_type != VBLK) {
354 		vrele(devvp);
355 		return (ENOTBLK);
356 	}
357 	if (bdevsw_lookup(devvp->v_rdev) == NULL) {
358 		vrele(devvp);
359 		return (ENXIO);
360 	}
361 	/*
362 	 * If mount by non-root, then verify that user has necessary
363 	 * permissions on the device.
364 	 */
365 	if (p->p_ucred->cr_uid != 0) {
366 		accessmode = VREAD;
367 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
368 			accessmode |= VWRITE;
369 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
370 		error = VOP_ACCESS(devvp, accessmode, p->p_ucred, p);
371 		VOP_UNLOCK(devvp, 0);
372 		if (error) {
373 			vrele(devvp);
374 			return (error);
375 		}
376 	}
377 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
378 		error = msdosfs_mountfs(devvp, mp, p, &args);
379 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
380 		pmp = VFSTOMSDOSFS(mp);
381 #endif
382 	} else {
383 		if (devvp != pmp->pm_devvp)
384 			error = EINVAL;	/* needs translation */
385 		else
386 			vrele(devvp);
387 	}
388 	if (error) {
389 		vrele(devvp);
390 		return (error);
391 	}
392 
393 	if ((error = update_mp(mp, &args)) != 0) {
394 		msdosfs_unmount(mp, MNT_FORCE, p);
395 		return error;
396 	}
397 
398 #ifdef MSDOSFS_DEBUG
399 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
400 #endif
401 	return set_statvfs_info(path, UIO_USERSPACE, args.fspec, UIO_USERSPACE,
402 	    mp, p);
403 }
404 
405 int
406 msdosfs_mountfs(devvp, mp, p, argp)
407 	struct vnode *devvp;
408 	struct mount *mp;
409 	struct proc *p;
410 	struct msdosfs_args *argp;
411 {
412 	struct msdosfsmount *pmp;
413 	struct buf *bp;
414 	dev_t dev = devvp->v_rdev;
415 	struct partinfo dpart;
416 	union bootsector *bsp;
417 	struct byte_bpb33 *b33;
418 	struct byte_bpb50 *b50;
419 	struct byte_bpb710 *b710;
420 	u_int8_t SecPerClust;
421 	int	ronly, error;
422 	int	bsize = 0, dtype = 0, tmp;
423 	u_long	dirsperblk;
424 
425 	/*
426 	 * Disallow multiple mounts of the same device.
427 	 * Disallow mounting of a device that is currently in use
428 	 * (except for root, which might share swap device for miniroot).
429 	 * Flush out any old buffers remaining from a previous use.
430 	 */
431 	if ((error = vfs_mountedon(devvp)) != 0)
432 		return (error);
433 	if (vcount(devvp) > 1 && devvp != rootvp)
434 		return (EBUSY);
435 	if ((error = vinvalbuf(devvp, V_SAVE, p->p_ucred, p, 0, 0)) != 0)
436 		return (error);
437 
438 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
439 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, p);
440 	if (error)
441 		return (error);
442 
443 	bp  = NULL; /* both used in error_exit */
444 	pmp = NULL;
445 
446 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
447 		/*
448 	 	 * We need the disklabel to calculate the size of a FAT entry
449 		 * later on. Also make sure the partition contains a filesystem
450 		 * of type FS_MSDOS. This doesn't work for floppies, so we have
451 		 * to check for them too.
452 	 	 *
453 	 	 * At least some parts of the msdos fs driver seem to assume
454 		 * that the size of a disk block will always be 512 bytes.
455 		 * Let's check it...
456 		 */
457 		error = VOP_IOCTL(devvp, DIOCGPART, &dpart, FREAD, NOCRED, p);
458 		if (error)
459 			goto error_exit;
460 		tmp   = dpart.part->p_fstype;
461 		dtype = dpart.disklab->d_type;
462 		bsize = dpart.disklab->d_secsize;
463 		if (bsize != 512 || (dtype!=DTYPE_FLOPPY && tmp!=FS_MSDOS)) {
464 			error = EINVAL;
465 			goto error_exit;
466 		}
467 	}
468 
469 	/*
470 	 * Read the boot sector of the filesystem, and then check the
471 	 * boot signature.  If not a dos boot sector then error out.
472 	 */
473 	if ((error = bread(devvp, 0, 512, NOCRED, &bp)) != 0)
474 		goto error_exit;
475 	bp->b_flags |= B_AGE;
476 	bsp = (union bootsector *)bp->b_data;
477 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
478 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
479 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
480 
481 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
482 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
483 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
484 			error = EINVAL;
485 			goto error_exit;
486 		}
487 	}
488 
489 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK);
490 	memset(pmp, 0, sizeof *pmp);
491 	pmp->pm_mountp = mp;
492 
493 	/*
494 	 * Compute several useful quantities from the bpb in the
495 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
496 	 * the fields that are different between dos 5 and dos 3.3.
497 	 */
498 	SecPerClust = b50->bpbSecPerClust;
499 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
500 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
501 	pmp->pm_FATs = b50->bpbFATs;
502 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
503 	pmp->pm_Sectors = getushort(b50->bpbSectors);
504 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
505 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
506 	pmp->pm_Heads = getushort(b50->bpbHeads);
507 	pmp->pm_Media = b50->bpbMedia;
508 
509 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
510 		/* XXX - We should probably check more values here */
511     		if (!pmp->pm_BytesPerSec || !SecPerClust
512 	    		|| pmp->pm_Heads > 255 || pmp->pm_SecPerTrack > 63) {
513 			error = EINVAL;
514 			goto error_exit;
515 		}
516 	}
517 
518 	if (pmp->pm_Sectors == 0) {
519 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
520 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
521 	} else {
522 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
523 		pmp->pm_HugeSectors = pmp->pm_Sectors;
524 	}
525 	dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
526 	if (pmp->pm_HugeSectors > 0xffffffff / dirsperblk + 1) {
527 		/*
528 		 * We cannot deal currently with this size of disk
529 		 * due to fileid limitations (see msdosfs_getattr and
530 		 * msdosfs_readdir)
531 		 */
532 		error = EINVAL;
533 		goto error_exit;
534 	}
535 
536 	if (pmp->pm_RootDirEnts == 0) {
537 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
538 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
539 		    || pmp->pm_Sectors
540 		    || pmp->pm_FATsecs
541 		    || getushort(b710->bpbFSVers)) {
542 			error = EINVAL;
543 			goto error_exit;
544 		}
545 		pmp->pm_fatmask = FAT32_MASK;
546 		pmp->pm_fatmult = 4;
547 		pmp->pm_fatdiv = 1;
548 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
549 
550 		/* mirrorring is enabled if the FATMIRROR bit is not set */
551 		if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
552 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
553 		else
554 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
555 	} else
556 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
557 
558 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
559 		if (FAT32(pmp)) {
560 			/*
561 			 * GEMDOS doesn't know fat32.
562 			 */
563 			error = EINVAL;
564 			goto error_exit;
565 		}
566 
567 		/*
568 		 * Check a few values (could do some more):
569 		 * - logical sector size: power of 2, >= block size
570 		 * - sectors per cluster: power of 2, >= 1
571 		 * - number of sectors:   >= 1, <= size of partition
572 		 */
573 		if ( (SecPerClust == 0)
574 		  || (SecPerClust & (SecPerClust - 1))
575 		  || (pmp->pm_BytesPerSec < bsize)
576 		  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
577 		  || (pmp->pm_HugeSectors == 0)
578 		  || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize)
579 							> dpart.part->p_size)
580 		   ) {
581 			error = EINVAL;
582 			goto error_exit;
583 		}
584 		/*
585 		 * XXX - Many parts of the msdos fs driver seem to assume that
586 		 * the number of bytes per logical sector (BytesPerSec) will
587 		 * always be the same as the number of bytes per disk block
588 		 * Let's pretend it is.
589 		 */
590 		tmp = pmp->pm_BytesPerSec / bsize;
591 		pmp->pm_BytesPerSec  = bsize;
592 		pmp->pm_HugeSectors *= tmp;
593 		pmp->pm_HiddenSects *= tmp;
594 		pmp->pm_ResSectors  *= tmp;
595 		pmp->pm_Sectors     *= tmp;
596 		pmp->pm_FATsecs     *= tmp;
597 		SecPerClust         *= tmp;
598 	}
599 	pmp->pm_fatblk = pmp->pm_ResSectors;
600 	if (FAT32(pmp)) {
601 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
602 		pmp->pm_firstcluster = pmp->pm_fatblk
603 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
604 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
605 	} else {
606 		pmp->pm_rootdirblk = pmp->pm_fatblk +
607 			(pmp->pm_FATs * pmp->pm_FATsecs);
608 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
609 				       + pmp->pm_BytesPerSec - 1)
610 			/ pmp->pm_BytesPerSec;/* in sectors */
611 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
612 	}
613 
614 	pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
615 	    SecPerClust;
616 	pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
617 	pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
618 
619 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
620 		if (pmp->pm_nmbrofclusters <= (0xff0 - 2)
621 		      && (dtype == DTYPE_FLOPPY
622 			  || (dtype == DTYPE_VND
623 				&& (pmp->pm_Heads == 1 || pmp->pm_Heads == 2)))
624 		    ) {
625 			pmp->pm_fatmask = FAT12_MASK;
626 			pmp->pm_fatmult = 3;
627 			pmp->pm_fatdiv = 2;
628 		} else {
629 			pmp->pm_fatmask = FAT16_MASK;
630 			pmp->pm_fatmult = 2;
631 			pmp->pm_fatdiv = 1;
632 		}
633 	} else if (pmp->pm_fatmask == 0) {
634 		if (pmp->pm_maxcluster
635 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
636 			/*
637 			 * This will usually be a floppy disk. This size makes
638 			 * sure that one fat entry will not be split across
639 			 * multiple blocks.
640 			 */
641 			pmp->pm_fatmask = FAT12_MASK;
642 			pmp->pm_fatmult = 3;
643 			pmp->pm_fatdiv = 2;
644 		} else {
645 			pmp->pm_fatmask = FAT16_MASK;
646 			pmp->pm_fatmult = 2;
647 			pmp->pm_fatdiv = 1;
648 		}
649 	}
650 	if (FAT12(pmp))
651 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
652 	else
653 		pmp->pm_fatblocksize = MAXBSIZE;
654 
655 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
656 	pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
657 
658 	/*
659 	 * Compute mask and shift value for isolating cluster relative byte
660 	 * offsets and cluster numbers from a file offset.
661 	 */
662 	pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
663 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
664 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
665 
666 	/*
667 	 * Check for valid cluster size
668 	 * must be a power of 2
669 	 */
670 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
671 		error = EINVAL;
672 		goto error_exit;
673 	}
674 
675 	/*
676 	 * Release the bootsector buffer.
677 	 */
678 	brelse(bp);
679 	bp = NULL;
680 
681 	/*
682 	 * Check FSInfo.
683 	 */
684 	if (pmp->pm_fsinfo) {
685 		struct fsinfo *fp;
686 
687 		if ((error = bread(devvp, pmp->pm_fsinfo, 1024, NOCRED, &bp)) != 0)
688 			goto error_exit;
689 		fp = (struct fsinfo *)bp->b_data;
690 		if (!memcmp(fp->fsisig1, "RRaA", 4)
691 		    && !memcmp(fp->fsisig2, "rrAa", 4)
692 		    && !memcmp(fp->fsisig3, "\0\0\125\252", 4)
693 		    && !memcmp(fp->fsisig4, "\0\0\125\252", 4))
694 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
695 		else
696 			pmp->pm_fsinfo = 0;
697 		brelse(bp);
698 		bp = NULL;
699 	}
700 
701 	/*
702 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
703 	 * XXX
704 	 */
705 	if (pmp->pm_fsinfo) {
706 		if (pmp->pm_nxtfree == (u_long)-1)
707 			pmp->pm_fsinfo = 0;
708 	}
709 
710 	/*
711 	 * Allocate memory for the bitmap of allocated clusters, and then
712 	 * fill it in.
713 	 */
714 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
715 				   / N_INUSEBITS)
716 				  * sizeof(*pmp->pm_inusemap),
717 				  M_MSDOSFSFAT, M_WAITOK);
718 
719 	/*
720 	 * fillinusemap() needs pm_devvp.
721 	 */
722 	pmp->pm_dev = dev;
723 	pmp->pm_devvp = devvp;
724 
725 	/*
726 	 * Have the inuse map filled in.
727 	 */
728 	if ((error = fillinusemap(pmp)) != 0)
729 		goto error_exit;
730 
731 	/*
732 	 * If they want fat updates to be synchronous then let them suffer
733 	 * the performance degradation in exchange for the on disk copy of
734 	 * the fat being correct just about all the time.  I suppose this
735 	 * would be a good thing to turn on if the kernel is still flakey.
736 	 */
737 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
738 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
739 
740 	/*
741 	 * Finish up.
742 	 */
743 	if (ronly)
744 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
745 	else
746 		pmp->pm_fmod = 1;
747 	mp->mnt_data = pmp;
748 	mp->mnt_stat.f_fsidx.__fsid_val[0] = (long)dev;
749 	mp->mnt_stat.f_fsidx.__fsid_val[1] = makefstype(MOUNT_MSDOS);
750 	mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
751 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
752 	mp->mnt_flag |= MNT_LOCAL;
753 	mp->mnt_dev_bshift = pmp->pm_bnshift;
754 	mp->mnt_fs_bshift = pmp->pm_cnshift;
755 
756 #ifdef QUOTA
757 	/*
758 	 * If we ever do quotas for DOS filesystems this would be a place
759 	 * to fill in the info in the msdosfsmount structure. You dolt,
760 	 * quotas on dos filesystems make no sense because files have no
761 	 * owners on dos filesystems. of course there is some empty space
762 	 * in the directory entry where we could put uid's and gid's.
763 	 */
764 #endif
765 	devvp->v_specmountpoint = mp;
766 
767 	return (0);
768 
769 error_exit:;
770 	if (bp)
771 		brelse(bp);
772 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
773 	(void) VOP_CLOSE(devvp, ronly ? FREAD : FREAD|FWRITE, NOCRED, p);
774 	VOP_UNLOCK(devvp, 0);
775 	if (pmp) {
776 		if (pmp->pm_inusemap)
777 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
778 		free(pmp, M_MSDOSFSMNT);
779 		mp->mnt_data = NULL;
780 	}
781 	return (error);
782 }
783 
784 int
785 msdosfs_start(mp, flags, p)
786 	struct mount *mp;
787 	int flags;
788 	struct proc *p;
789 {
790 
791 	return (0);
792 }
793 
794 /*
795  * Unmount the filesystem described by mp.
796  */
797 int
798 msdosfs_unmount(mp, mntflags, p)
799 	struct mount *mp;
800 	int mntflags;
801 	struct proc *p;
802 {
803 	struct msdosfsmount *pmp;
804 	int error, flags;
805 
806 	flags = 0;
807 	if (mntflags & MNT_FORCE)
808 		flags |= FORCECLOSE;
809 #ifdef QUOTA
810 #endif
811 	if ((error = vflush(mp, NULLVP, flags)) != 0)
812 		return (error);
813 	pmp = VFSTOMSDOSFS(mp);
814 	if (pmp->pm_devvp->v_type != VBAD)
815 		pmp->pm_devvp->v_specmountpoint = NULL;
816 #ifdef MSDOSFS_DEBUG
817 	{
818 		struct vnode *vp = pmp->pm_devvp;
819 
820 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
821 		printf("flag %08x, usecount %d, writecount %ld, holdcnt %ld\n",
822 		    vp->v_flag, vp->v_usecount, vp->v_writecount, vp->v_holdcnt);
823 		printf("id %lu, mount %p, op %p\n",
824 		    vp->v_id, vp->v_mount, vp->v_op);
825 		printf("freef %p, freeb %p, mount %p\n",
826 		    vp->v_freelist.tqe_next, vp->v_freelist.tqe_prev,
827 		    vp->v_mount);
828 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %d, type %d\n",
829 		    vp->v_cleanblkhd.lh_first,
830 		    vp->v_dirtyblkhd.lh_first,
831 		    vp->v_numoutput, vp->v_type);
832 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
833 		    vp->v_socket, vp->v_tag,
834 		    ((u_int *)vp->v_data)[0],
835 		    ((u_int *)vp->v_data)[1]);
836 	}
837 #endif
838 	vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
839 	error = VOP_CLOSE(pmp->pm_devvp,
840 	    pmp->pm_flags & MSDOSFSMNT_RONLY ? FREAD : FREAD|FWRITE, NOCRED, p);
841 	vput(pmp->pm_devvp);
842 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
843 	free(pmp, M_MSDOSFSMNT);
844 	mp->mnt_data = NULL;
845 	mp->mnt_flag &= ~MNT_LOCAL;
846 	return (error);
847 }
848 
849 int
850 msdosfs_root(mp, vpp)
851 	struct mount *mp;
852 	struct vnode **vpp;
853 {
854 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
855 	struct denode *ndep;
856 	int error;
857 
858 #ifdef MSDOSFS_DEBUG
859 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
860 #endif
861 	if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0)
862 		return (error);
863 	*vpp = DETOV(ndep);
864 	return (0);
865 }
866 
867 int
868 msdosfs_quotactl(mp, cmds, uid, arg, p)
869 	struct mount *mp;
870 	int cmds;
871 	uid_t uid;
872 	void *arg;
873 	struct proc *p;
874 {
875 
876 #ifdef QUOTA
877 	return (EOPNOTSUPP);
878 #else
879 	return (EOPNOTSUPP);
880 #endif
881 }
882 
883 int
884 msdosfs_statvfs(mp, sbp, p)
885 	struct mount *mp;
886 	struct statvfs *sbp;
887 	struct proc *p;
888 {
889 	struct msdosfsmount *pmp;
890 
891 	pmp = VFSTOMSDOSFS(mp);
892 	sbp->f_bsize = pmp->pm_bpcluster;
893 	sbp->f_frsize = sbp->f_bsize;
894 	sbp->f_iosize = pmp->pm_bpcluster;
895 	sbp->f_blocks = pmp->pm_nmbrofclusters;
896 	sbp->f_bfree = pmp->pm_freeclustercount;
897 	sbp->f_bavail = pmp->pm_freeclustercount;
898 	sbp->f_bresvd = 0;
899 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
900 	sbp->f_ffree = 0;	/* what to put in here? */
901 	sbp->f_favail = 0;	/* what to put in here? */
902 	sbp->f_fresvd = 0;
903 	copy_statvfs_info(sbp, mp);
904 	return (0);
905 }
906 
907 int
908 msdosfs_sync(mp, waitfor, cred, p)
909 	struct mount *mp;
910 	int waitfor;
911 	struct ucred *cred;
912 	struct proc *p;
913 {
914 	struct vnode *vp, *nvp;
915 	struct denode *dep;
916 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
917 	int error, allerror = 0;
918 
919 	/*
920 	 * If we ever switch to not updating all of the fats all the time,
921 	 * this would be the place to update them from the first one.
922 	 */
923 	if (pmp->pm_fmod != 0) {
924 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
925 			panic("msdosfs_sync: rofs mod");
926 		else {
927 			/* update fats here */
928 		}
929 	}
930 	/*
931 	 * Write back each (modified) denode.
932 	 */
933 	simple_lock(&mntvnode_slock);
934 loop:
935 	for (vp = mp->mnt_vnodelist.lh_first; vp != NULL; vp = nvp) {
936 		/*
937 		 * If the vnode that we are about to sync is no longer
938 		 * assoicated with this mount point, start over.
939 		 */
940 		if (vp->v_mount != mp)
941 			goto loop;
942 		simple_lock(&vp->v_interlock);
943 		nvp = vp->v_mntvnodes.le_next;
944 		dep = VTODE(vp);
945 		if (waitfor == MNT_LAZY || vp->v_type == VNON ||
946 		    (((dep->de_flag &
947 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0) &&
948 		     (LIST_EMPTY(&vp->v_dirtyblkhd) &&
949 		      vp->v_uobj.uo_npages == 0))) {
950 			simple_unlock(&vp->v_interlock);
951 			continue;
952 		}
953 		simple_unlock(&mntvnode_slock);
954 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK);
955 		if (error) {
956 			simple_lock(&mntvnode_slock);
957 			if (error == ENOENT)
958 				goto loop;
959 			continue;
960 		}
961 		if ((error = VOP_FSYNC(vp, cred,
962 		    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0, p)) != 0)
963 			allerror = error;
964 		vput(vp);
965 		simple_lock(&mntvnode_slock);
966 	}
967 	simple_unlock(&mntvnode_slock);
968 	/*
969 	 * Force stale file system control information to be flushed.
970 	 */
971 	if ((error = VOP_FSYNC(pmp->pm_devvp, cred,
972 	    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0, p)) != 0)
973 		allerror = error;
974 #ifdef QUOTA
975 	/* qsync(mp); */
976 #endif
977 	return (allerror);
978 }
979 
980 int
981 msdosfs_fhtovp(mp, fhp, vpp)
982 	struct mount *mp;
983 	struct fid *fhp;
984 	struct vnode **vpp;
985 {
986 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
987 	struct defid *defhp = (struct defid *) fhp;
988 	struct denode *dep;
989 	int error;
990 
991 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
992 	if (error) {
993 		*vpp = NULLVP;
994 		return (error);
995 	}
996 	*vpp = DETOV(dep);
997 	return (0);
998 }
999 
1000 int
1001 msdosfs_checkexp(mp, nam, exflagsp, credanonp)
1002 	struct mount *mp;
1003 	struct mbuf *nam;
1004 	int *exflagsp;
1005 	struct ucred **credanonp;
1006 {
1007 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
1008 	struct netcred *np;
1009 
1010 	np = vfs_export_lookup(mp, &pmp->pm_export, nam);
1011 	if (np == NULL)
1012 		return (EACCES);
1013 	*exflagsp = np->netc_exflags;
1014 	*credanonp = &np->netc_anon;
1015 	return (0);
1016 }
1017 
1018 int
1019 msdosfs_vptofh(vp, fhp)
1020 	struct vnode *vp;
1021 	struct fid *fhp;
1022 {
1023 	struct denode *dep;
1024 	struct defid *defhp;
1025 
1026 	dep = VTODE(vp);
1027 	defhp = (struct defid *)fhp;
1028 	defhp->defid_len = sizeof(struct defid);
1029 	defhp->defid_dirclust = dep->de_dirclust;
1030 	defhp->defid_dirofs = dep->de_diroffset;
1031 	/* defhp->defid_gen = dep->de_gen; */
1032 	return (0);
1033 }
1034 
1035 int
1036 msdosfs_vget(mp, ino, vpp)
1037 	struct mount *mp;
1038 	ino_t ino;
1039 	struct vnode **vpp;
1040 {
1041 
1042 	return (EOPNOTSUPP);
1043 }
1044 
1045 SYSCTL_SETUP(sysctl_vfs_msdosfs_setup, "sysctl vfs.msdosfs subtree setup")
1046 {
1047 
1048 	sysctl_createv(clog, 0, NULL, NULL,
1049 		       CTLFLAG_PERMANENT,
1050 		       CTLTYPE_NODE, "vfs", NULL,
1051 		       NULL, 0, NULL, 0,
1052 		       CTL_VFS, CTL_EOL);
1053 	sysctl_createv(clog, 0, NULL, NULL,
1054 		       CTLFLAG_PERMANENT,
1055 		       CTLTYPE_NODE, "msdosfs",
1056 		       SYSCTL_DESCR("MS-DOS file system"),
1057 		       NULL, 0, NULL, 0,
1058 		       CTL_VFS, 4, CTL_EOL);
1059 	/*
1060 	 * XXX the "4" above could be dynamic, thereby eliminating one
1061 	 * more instance of the "number to vfs" mapping problem, but
1062 	 * "4" is the order as taken from sys/mount.h
1063 	 */
1064 }
1065