xref: /netbsd-src/sys/fs/msdosfs/msdosfs_vfsops.c (revision cd22f25e6f6d1cc1f197fe8c5468a80f51d1c4e1)
1 /*	$NetBSD: msdosfs_vfsops.c,v 1.64 2008/04/30 14:07:14 ad 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 1.64 2008/04/30 14:07:14 ad 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/genfs/genfs.h>
66 #include <miscfs/specfs/specdev.h> /* XXX */	/* defines v_rdev */
67 #include <sys/mount.h>
68 #include <sys/buf.h>
69 #include <sys/file.h>
70 #include <sys/device.h>
71 #include <sys/disklabel.h>
72 #include <sys/disk.h>
73 #include <sys/ioctl.h>
74 #include <sys/malloc.h>
75 #include <sys/dirent.h>
76 #include <sys/stat.h>
77 #include <sys/conf.h>
78 #include <sys/kauth.h>
79 
80 #include <fs/msdosfs/bpb.h>
81 #include <fs/msdosfs/bootsect.h>
82 #include <fs/msdosfs/direntry.h>
83 #include <fs/msdosfs/denode.h>
84 #include <fs/msdosfs/msdosfsmount.h>
85 #include <fs/msdosfs/fat.h>
86 
87 #ifdef MSDOSFS_DEBUG
88 #define DPRINTF(a) uprintf a
89 #else
90 #define DPRINTF(a)
91 #endif
92 
93 #define MSDOSFS_NAMEMAX(pmp) \
94 	(pmp)->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12
95 
96 VFS_PROTOS(msdosfs);
97 
98 int msdosfs_mountfs(struct vnode *, struct mount *, struct lwp *,
99     struct msdosfs_args *);
100 
101 static int update_mp(struct mount *, struct msdosfs_args *);
102 
103 MALLOC_JUSTDEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOS FS mount structure");
104 MALLOC_JUSTDEFINE(M_MSDOSFSFAT, "MSDOSFS fat", "MSDOS FS fat table");
105 MALLOC_JUSTDEFINE(M_MSDOSFSTMP, "MSDOSFS temp", "MSDOS FS temp. structures");
106 
107 #define ROOTNAME "root_device"
108 
109 extern const struct vnodeopv_desc msdosfs_vnodeop_opv_desc;
110 
111 const struct vnodeopv_desc * const msdosfs_vnodeopv_descs[] = {
112 	&msdosfs_vnodeop_opv_desc,
113 	NULL,
114 };
115 
116 struct vfsops msdosfs_vfsops = {
117 	MOUNT_MSDOS,
118 	sizeof (struct msdosfs_args),
119 	msdosfs_mount,
120 	msdosfs_start,
121 	msdosfs_unmount,
122 	msdosfs_root,
123 	(void *)eopnotsupp,		/* vfs_quotactl */
124 	msdosfs_statvfs,
125 	msdosfs_sync,
126 	msdosfs_vget,
127 	msdosfs_fhtovp,
128 	msdosfs_vptofh,
129 	msdosfs_init,
130 	msdosfs_reinit,
131 	msdosfs_done,
132 	msdosfs_mountroot,
133 	(int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
134 	vfs_stdextattrctl,
135 	(void *)eopnotsupp,		/* vfs_suspendctl */
136 	genfs_renamelock_enter,
137 	genfs_renamelock_exit,
138 	(void *)eopnotsupp,
139 	msdosfs_vnodeopv_descs,
140 	0,
141 	{ NULL, NULL },
142 };
143 VFS_ATTACH(msdosfs_vfsops);
144 
145 static int
146 update_mp(mp, argp)
147 	struct mount *mp;
148 	struct msdosfs_args *argp;
149 {
150 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
151 	int error;
152 
153 	pmp->pm_gid = argp->gid;
154 	pmp->pm_uid = argp->uid;
155 	pmp->pm_mask = argp->mask & ALLPERMS;
156 	pmp->pm_dirmask = argp->dirmask & ALLPERMS;
157 	pmp->pm_gmtoff = argp->gmtoff;
158 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
159 
160 	/*
161 	 * GEMDOS knows nothing (yet) about win95
162 	 */
163 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
164 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
165 
166 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
167 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
168 	else if (!(pmp->pm_flags &
169 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
170 		struct vnode *rtvp;
171 
172 		/*
173 		 * Try to divine whether to support Win'95 long filenames
174 		 */
175 		if (FAT32(pmp))
176 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
177 		else {
178 			if ((error = msdosfs_root(mp, &rtvp)) != 0)
179 				return error;
180 			pmp->pm_flags |= findwin95(VTODE(rtvp))
181 				? MSDOSFSMNT_LONGNAME
182 					: MSDOSFSMNT_SHORTNAME;
183 			vput(rtvp);
184 		}
185 	}
186 
187 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
188 
189 	return 0;
190 }
191 
192 int
193 msdosfs_mountroot()
194 {
195 	struct mount *mp;
196 	struct lwp *l = curlwp;	/* XXX */
197 	int error;
198 	struct msdosfs_args args;
199 
200 	if (device_class(root_device) != DV_DISK)
201 		return (ENODEV);
202 
203 	if ((error = vfs_rootmountalloc(MOUNT_MSDOS, "root_device", &mp))) {
204 		vrele(rootvp);
205 		return (error);
206 	}
207 
208 	args.flags = MSDOSFSMNT_VERSIONED;
209 	args.uid = 0;
210 	args.gid = 0;
211 	args.mask = 0777;
212 	args.version = MSDOSFSMNT_VERSION;
213 	args.dirmask = 0777;
214 
215 	if ((error = msdosfs_mountfs(rootvp, mp, l, &args)) != 0) {
216 		vfs_unbusy(mp, false, NULL);
217 		vfs_destroy(mp, false);
218 		return (error);
219 	}
220 
221 	if ((error = update_mp(mp, &args)) != 0) {
222 		(void)msdosfs_unmount(mp, 0);
223 		vfs_unbusy(mp, false, NULL);
224 		vfs_destroy(mp, false);
225 		vrele(rootvp);
226 		return (error);
227 	}
228 
229 	mutex_enter(&mountlist_lock);
230 	CIRCLEQ_INSERT_TAIL(&mountlist, mp, mnt_list);
231 	mp->mnt_iflag |= IMNT_ONLIST;
232 	mutex_exit(&mountlist_lock);
233 	(void)msdosfs_statvfs(mp, &mp->mnt_stat);
234 	vfs_unbusy(mp, false, NULL);
235 	return (0);
236 }
237 
238 /*
239  * mp - path - addr in user space of mount point (ie /usr or whatever)
240  * data - addr in user space of mount params including the name of the block
241  * special file to treat as a filesystem.
242  */
243 int
244 msdosfs_mount(mp, path, data, data_len)
245 	struct mount *mp;
246 	const char *path;
247 	void *data;
248 	size_t *data_len;
249 {
250 	struct lwp *l = curlwp;
251 	struct nameidata nd;
252 	struct vnode *devvp;	  /* vnode for blk device to mount */
253 	struct msdosfs_args *args = data; /* holds data from mount request */
254 	/* msdosfs specific mount control block */
255 	struct msdosfsmount *pmp = NULL;
256 	int error, flags;
257 	mode_t accessmode;
258 
259 	if (*data_len < sizeof *args)
260 		return EINVAL;
261 
262 	if (mp->mnt_flag & MNT_GETARGS) {
263 		pmp = VFSTOMSDOSFS(mp);
264 		if (pmp == NULL)
265 			return EIO;
266 		args->fspec = NULL;
267 		args->uid = pmp->pm_uid;
268 		args->gid = pmp->pm_gid;
269 		args->mask = pmp->pm_mask;
270 		args->flags = pmp->pm_flags;
271 		args->version = MSDOSFSMNT_VERSION;
272 		args->dirmask = pmp->pm_dirmask;
273 		args->gmtoff = pmp->pm_gmtoff;
274 		*data_len = sizeof *args;
275 		return 0;
276 	}
277 
278 	/*
279 	 * If not versioned (i.e. using old mount_msdos(8)), fill in
280 	 * the additional structure items with suitable defaults.
281 	 */
282 	if ((args->flags & MSDOSFSMNT_VERSIONED) == 0) {
283 		args->version = 1;
284 		args->dirmask = args->mask;
285 	}
286 
287 	/*
288 	 * Reset GMT offset for pre-v3 mount structure args.
289 	 */
290 	if (args->version < 3)
291 		args->gmtoff = 0;
292 
293 	/*
294 	 * If updating, check whether changing from read-only to
295 	 * read/write; if there is no device name, that's all we do.
296 	 */
297 	if (mp->mnt_flag & MNT_UPDATE) {
298 		pmp = VFSTOMSDOSFS(mp);
299 		error = 0;
300 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
301 			flags = WRITECLOSE;
302 			if (mp->mnt_flag & MNT_FORCE)
303 				flags |= FORCECLOSE;
304 			error = vflush(mp, NULLVP, flags);
305 		}
306 		if (!error && (mp->mnt_flag & MNT_RELOAD))
307 			/* not yet implemented */
308 			error = EOPNOTSUPP;
309 		if (error) {
310 			DPRINTF(("vflush %d\n", error));
311 			return (error);
312 		}
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 (kauth_authorize_generic(l->l_cred,
319 			    KAUTH_GENERIC_ISSUSER, NULL) != 0) {
320 				devvp = pmp->pm_devvp;
321 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
322 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
323 						   l->l_cred);
324 				VOP_UNLOCK(devvp, 0);
325 				DPRINTF(("VOP_ACCESS %d\n", error));
326 				if (error)
327 					return (error);
328 			}
329 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
330 		}
331 		if (args->fspec == NULL) {
332 			DPRINTF(("missing fspec\n"));
333 			return EINVAL;
334 		}
335 	}
336 	/*
337 	 * Not an update, or updating the name: look up the name
338 	 * and verify that it refers to a sensible block device.
339 	 */
340 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, args->fspec);
341 	if ((error = namei(&nd)) != 0) {
342 		DPRINTF(("namei %d\n", error));
343 		return (error);
344 	}
345 	devvp = nd.ni_vp;
346 
347 	if (devvp->v_type != VBLK) {
348 		DPRINTF(("not block\n"));
349 		vrele(devvp);
350 		return (ENOTBLK);
351 	}
352 	if (bdevsw_lookup(devvp->v_rdev) == NULL) {
353 		DPRINTF(("no block switch\n"));
354 		vrele(devvp);
355 		return (ENXIO);
356 	}
357 	/*
358 	 * If mount by non-root, then verify that user has necessary
359 	 * permissions on the device.
360 	 */
361 	if (kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER, NULL) != 0) {
362 		accessmode = VREAD;
363 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
364 			accessmode |= VWRITE;
365 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
366 		error = VOP_ACCESS(devvp, accessmode, l->l_cred);
367 		VOP_UNLOCK(devvp, 0);
368 		if (error) {
369 			DPRINTF(("VOP_ACCESS2 %d\n", error));
370 			vrele(devvp);
371 			return (error);
372 		}
373 	}
374 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
375 		int xflags;
376 
377 		if (mp->mnt_flag & MNT_RDONLY)
378 			xflags = FREAD;
379 		else
380 			xflags = FREAD|FWRITE;
381 		error = VOP_OPEN(devvp, xflags, FSCRED);
382 		if (error) {
383 			DPRINTF(("VOP_OPEN %d\n", error));
384 			goto fail;
385 		}
386 		error = msdosfs_mountfs(devvp, mp, l, args);
387 		if (error) {
388 			DPRINTF(("msdosfs_mountfs %d\n", error));
389 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
390 			(void) VOP_CLOSE(devvp, xflags, NOCRED);
391 			VOP_UNLOCK(devvp, 0);
392 			goto fail;
393 		}
394 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
395 		pmp = VFSTOMSDOSFS(mp);
396 #endif
397 	} else {
398 		vrele(devvp);
399 		if (devvp != pmp->pm_devvp) {
400 			DPRINTF(("devvp %p pmp %p\n",
401 			    devvp, pmp->pm_devvp));
402 			return (EINVAL);	/* needs translation */
403 		}
404 	}
405 	if ((error = update_mp(mp, args)) != 0) {
406 		msdosfs_unmount(mp, MNT_FORCE);
407 		DPRINTF(("update_mp %d\n", error));
408 		return error;
409 	}
410 
411 #ifdef MSDOSFS_DEBUG
412 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
413 #endif
414 	return set_statvfs_info(path, UIO_USERSPACE, args->fspec, UIO_USERSPACE,
415 	    mp->mnt_op->vfs_name, mp, l);
416 
417 fail:
418 	vrele(devvp);
419 	return (error);
420 }
421 
422 int
423 msdosfs_mountfs(devvp, mp, l, argp)
424 	struct vnode *devvp;
425 	struct mount *mp;
426 	struct lwp *l;
427 	struct msdosfs_args *argp;
428 {
429 	struct msdosfsmount *pmp;
430 	struct buf *bp;
431 	dev_t dev = devvp->v_rdev;
432 	struct partinfo dpart;
433 	union bootsector *bsp;
434 	struct byte_bpb33 *b33;
435 	struct byte_bpb50 *b50;
436 	struct byte_bpb710 *b710;
437 	u_int8_t SecPerClust;
438 	int	ronly, error, tmp;
439 	int	bsize, dtype, fstype, secsize;
440 	u_int64_t psize;
441 
442 	/* Flush out any old buffers remaining from a previous use. */
443 	if ((error = vinvalbuf(devvp, V_SAVE, l->l_cred, l, 0, 0)) != 0)
444 		return (error);
445 
446 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
447 
448 	bp  = NULL; /* both used in error_exit */
449 	pmp = NULL;
450 
451 	/*
452  	 * We need the disklabel to calculate the size of a FAT entry
453 	 * later on. Also make sure the partition contains a filesystem
454 	 * of type FS_MSDOS. This doesn't work for floppies, so we have
455 	 * to check for them too.
456  	 *
457  	 * There might still be parts of the msdos fs driver which assume
458 	 * that the size of a disk block will always be 512 bytes.
459 	 * Let's root them out...
460 	 */
461 	error = VOP_IOCTL(devvp, DIOCGPART, &dpart, FREAD, NOCRED);
462 	if (error == 0) {
463 		secsize = dpart.disklab->d_secsize;
464 		dtype = dpart.disklab->d_type;
465 		fstype = dpart.part->p_fstype;
466 		psize = dpart.part->p_size;
467 	} else {
468 		struct dkwedge_info dkw;
469 		error = VOP_IOCTL(devvp, DIOCGWEDGEINFO, &dkw, FREAD, NOCRED);
470 		secsize = 512;	/* XXX */
471 		dtype = DTYPE_FLOPPY; /* XXX */
472 		fstype = FS_MSDOS;
473 		psize = -1;
474 		if (error) {
475 			if (error != ENOTTY) {
476 				DPRINTF(("Error getting partition info %d\n",
477 				    error));
478 				goto error_exit;
479 			}
480 		} else {
481 			fstype = strcmp(dkw.dkw_ptype, DKW_PTYPE_FAT) == 0 ?
482 			    FS_MSDOS : -1;
483 			psize = dkw.dkw_size;
484 		}
485 	}
486 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
487 		bsize = secsize;
488 		if (bsize != 512 ||
489 		    (dtype != DTYPE_FLOPPY && fstype != FS_MSDOS)) {
490 			DPRINTF(("bsize %d dtype %d fstype %d\n", bsize, dtype,
491 			    fstype));
492 			error = EINVAL;
493 			goto error_exit;
494 		}
495 	} else
496 		bsize = 0;
497 
498 	/*
499 	 * Read the boot sector of the filesystem, and then check the
500 	 * boot signature.  If not a dos boot sector then error out.
501 	 */
502 	if ((error = bread(devvp, 0, secsize, NOCRED, &bp)) != 0)
503 		goto error_exit;
504 	bsp = (union bootsector *)bp->b_data;
505 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
506 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
507 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
508 
509 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
510 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
511 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
512 			DPRINTF(("bootsig0 %d bootsig1 %d\n",
513 			    bsp->bs50.bsBootSectSig0,
514 			    bsp->bs50.bsBootSectSig1));
515 			error = EINVAL;
516 			goto error_exit;
517 		}
518 	}
519 
520 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK);
521 	memset(pmp, 0, sizeof *pmp);
522 	pmp->pm_mountp = mp;
523 
524 	/*
525 	 * Compute several useful quantities from the bpb in the
526 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
527 	 * the fields that are different between dos 5 and dos 3.3.
528 	 */
529 	SecPerClust = b50->bpbSecPerClust;
530 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
531 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
532 	pmp->pm_FATs = b50->bpbFATs;
533 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
534 	pmp->pm_Sectors = getushort(b50->bpbSectors);
535 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
536 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
537 	pmp->pm_Heads = getushort(b50->bpbHeads);
538 	pmp->pm_Media = b50->bpbMedia;
539 
540 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
541 		/* XXX - We should probably check more values here */
542     		if (!pmp->pm_BytesPerSec || !SecPerClust
543 	    		|| pmp->pm_Heads > 255 || pmp->pm_SecPerTrack > 63) {
544 			DPRINTF(("bytespersec %d secperclust %d "
545 			    "heads %d secpertrack %d\n",
546 			    pmp->pm_BytesPerSec, SecPerClust,
547 			    pmp->pm_Heads, pmp->pm_SecPerTrack));
548 			error = EINVAL;
549 			goto error_exit;
550 		}
551 	}
552 
553 	if (pmp->pm_Sectors == 0) {
554 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
555 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
556 	} else {
557 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
558 		pmp->pm_HugeSectors = pmp->pm_Sectors;
559 	}
560 
561 	if (pmp->pm_RootDirEnts == 0) {
562 		unsigned short vers = getushort(b710->bpbFSVers);
563 		/*
564 		 * Some say that bsBootSectSig[23] must be zero, but
565 		 * Windows does not require this and some digital cameras
566 		 * do not set these to zero.  Therefore, do not insist.
567 		 */
568 		if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) {
569 			DPRINTF(("sectors %d fatsecs %lu vers %d\n",
570 			    pmp->pm_Sectors, pmp->pm_FATsecs, vers));
571 			error = EINVAL;
572 			goto error_exit;
573 		}
574 		pmp->pm_fatmask = FAT32_MASK;
575 		pmp->pm_fatmult = 4;
576 		pmp->pm_fatdiv = 1;
577 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
578 
579 		/* mirrorring is enabled if the FATMIRROR bit is not set */
580 		if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
581 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
582 		else
583 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
584 	} else
585 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
586 
587 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
588 		if (FAT32(pmp)) {
589 			DPRINTF(("fat32 for gemdos\n"));
590 			/*
591 			 * GEMDOS doesn't know fat32.
592 			 */
593 			error = EINVAL;
594 			goto error_exit;
595 		}
596 
597 		/*
598 		 * Check a few values (could do some more):
599 		 * - logical sector size: power of 2, >= block size
600 		 * - sectors per cluster: power of 2, >= 1
601 		 * - number of sectors:   >= 1, <= size of partition
602 		 */
603 		if ( (SecPerClust == 0)
604 		  || (SecPerClust & (SecPerClust - 1))
605 		  || (pmp->pm_BytesPerSec < bsize)
606 		  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
607 		  || (pmp->pm_HugeSectors == 0)
608 		  || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize)
609 		      > psize)) {
610 			DPRINTF(("consistency checks for gemdos\n"));
611 			error = EINVAL;
612 			goto error_exit;
613 		}
614 		/*
615 		 * XXX - Many parts of the msdos fs driver seem to assume that
616 		 * the number of bytes per logical sector (BytesPerSec) will
617 		 * always be the same as the number of bytes per disk block
618 		 * Let's pretend it is.
619 		 */
620 		tmp = pmp->pm_BytesPerSec / bsize;
621 		pmp->pm_BytesPerSec  = bsize;
622 		pmp->pm_HugeSectors *= tmp;
623 		pmp->pm_HiddenSects *= tmp;
624 		pmp->pm_ResSectors  *= tmp;
625 		pmp->pm_Sectors     *= tmp;
626 		pmp->pm_FATsecs     *= tmp;
627 		SecPerClust         *= tmp;
628 	}
629 
630 	/* Check that fs has nonzero FAT size */
631 	if (pmp->pm_FATsecs == 0) {
632 		DPRINTF(("FATsecs is 0\n"));
633 		error = EINVAL;
634 		goto error_exit;
635 	}
636 
637 	pmp->pm_fatblk = pmp->pm_ResSectors;
638 	if (FAT32(pmp)) {
639 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
640 		pmp->pm_firstcluster = pmp->pm_fatblk
641 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
642 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
643 	} else {
644 		pmp->pm_rootdirblk = pmp->pm_fatblk +
645 			(pmp->pm_FATs * pmp->pm_FATsecs);
646 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
647 				       + pmp->pm_BytesPerSec - 1)
648 			/ pmp->pm_BytesPerSec;/* in sectors */
649 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
650 	}
651 
652 	pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
653 	    SecPerClust;
654 	pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
655 	pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
656 
657 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
658 		if (pmp->pm_nmbrofclusters <= (0xff0 - 2)
659 		      && (dtype == DTYPE_FLOPPY
660 			  || (dtype == DTYPE_VND
661 				&& (pmp->pm_Heads == 1 || pmp->pm_Heads == 2)))
662 		    ) {
663 			pmp->pm_fatmask = FAT12_MASK;
664 			pmp->pm_fatmult = 3;
665 			pmp->pm_fatdiv = 2;
666 		} else {
667 			pmp->pm_fatmask = FAT16_MASK;
668 			pmp->pm_fatmult = 2;
669 			pmp->pm_fatdiv = 1;
670 		}
671 	} else if (pmp->pm_fatmask == 0) {
672 		if (pmp->pm_maxcluster
673 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
674 			/*
675 			 * This will usually be a floppy disk. This size makes
676 			 * sure that one fat entry will not be split across
677 			 * multiple blocks.
678 			 */
679 			pmp->pm_fatmask = FAT12_MASK;
680 			pmp->pm_fatmult = 3;
681 			pmp->pm_fatdiv = 2;
682 		} else {
683 			pmp->pm_fatmask = FAT16_MASK;
684 			pmp->pm_fatmult = 2;
685 			pmp->pm_fatdiv = 1;
686 		}
687 	}
688 	if (FAT12(pmp))
689 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
690 	else
691 		pmp->pm_fatblocksize = MAXBSIZE;
692 
693 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
694 	pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
695 
696 	/*
697 	 * Compute mask and shift value for isolating cluster relative byte
698 	 * offsets and cluster numbers from a file offset.
699 	 */
700 	pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
701 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
702 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
703 
704 	/*
705 	 * Check for valid cluster size
706 	 * must be a power of 2
707 	 */
708 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
709 		DPRINTF(("bpcluster %lu cnshift %lu\n",
710 		    pmp->pm_bpcluster, pmp->pm_cnshift));
711 		error = EINVAL;
712 		goto error_exit;
713 	}
714 
715 	/*
716 	 * Release the bootsector buffer.
717 	 */
718 	brelse(bp, BC_AGE);
719 	bp = NULL;
720 
721 	/*
722 	 * Check FSInfo.
723 	 */
724 	if (pmp->pm_fsinfo) {
725 		struct fsinfo *fp;
726 
727 		/*
728 		 * XXX	If the fsinfo block is stored on media with
729 		 *	2KB or larger sectors, is the fsinfo structure
730 		 *	padded at the end or in the middle?
731 		 */
732 		if ((error = bread(devvp, de_bn2kb(pmp, pmp->pm_fsinfo),
733 		    pmp->pm_BytesPerSec, NOCRED, &bp)) != 0)
734 			goto error_exit;
735 		fp = (struct fsinfo *)bp->b_data;
736 		if (!memcmp(fp->fsisig1, "RRaA", 4)
737 		    && !memcmp(fp->fsisig2, "rrAa", 4)
738 		    && !memcmp(fp->fsisig3, "\0\0\125\252", 4)
739 		    && !memcmp(fp->fsisig4, "\0\0\125\252", 4))
740 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
741 		else
742 			pmp->pm_fsinfo = 0;
743 		brelse(bp, 0);
744 		bp = NULL;
745 	}
746 
747 	/*
748 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
749 	 * XXX
750 	 */
751 	if (pmp->pm_fsinfo) {
752 		if (pmp->pm_nxtfree == (u_long)-1)
753 			pmp->pm_fsinfo = 0;
754 	}
755 
756 	/*
757 	 * Allocate memory for the bitmap of allocated clusters, and then
758 	 * fill it in.
759 	 */
760 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
761 				   / N_INUSEBITS)
762 				  * sizeof(*pmp->pm_inusemap),
763 				  M_MSDOSFSFAT, M_WAITOK);
764 
765 	/*
766 	 * fillinusemap() needs pm_devvp.
767 	 */
768 	pmp->pm_dev = dev;
769 	pmp->pm_devvp = devvp;
770 
771 	/*
772 	 * Have the inuse map filled in.
773 	 */
774 	if ((error = fillinusemap(pmp)) != 0) {
775 		DPRINTF(("fillinusemap %d\n", error));
776 		goto error_exit;
777 	}
778 
779 	/*
780 	 * If they want fat updates to be synchronous then let them suffer
781 	 * the performance degradation in exchange for the on disk copy of
782 	 * the fat being correct just about all the time.  I suppose this
783 	 * would be a good thing to turn on if the kernel is still flakey.
784 	 */
785 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
786 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
787 
788 	/*
789 	 * Finish up.
790 	 */
791 	if (ronly)
792 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
793 	else
794 		pmp->pm_fmod = 1;
795 	mp->mnt_data = pmp;
796 	mp->mnt_stat.f_fsidx.__fsid_val[0] = (long)dev;
797 	mp->mnt_stat.f_fsidx.__fsid_val[1] = makefstype(MOUNT_MSDOS);
798 	mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
799 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
800 	mp->mnt_flag |= MNT_LOCAL;
801 	mp->mnt_dev_bshift = pmp->pm_bnshift;
802 	mp->mnt_fs_bshift = pmp->pm_cnshift;
803 
804 #ifdef QUOTA
805 	/*
806 	 * If we ever do quotas for DOS filesystems this would be a place
807 	 * to fill in the info in the msdosfsmount structure. You dolt,
808 	 * quotas on dos filesystems make no sense because files have no
809 	 * owners on dos filesystems. of course there is some empty space
810 	 * in the directory entry where we could put uid's and gid's.
811 	 */
812 #endif
813 	devvp->v_specmountpoint = mp;
814 
815 	return (0);
816 
817 error_exit:;
818 	if (bp)
819 		brelse(bp, BC_AGE);
820 	if (pmp) {
821 		if (pmp->pm_inusemap)
822 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
823 		free(pmp, M_MSDOSFSMNT);
824 		mp->mnt_data = NULL;
825 	}
826 	return (error);
827 }
828 
829 int
830 msdosfs_start(struct mount *mp, int flags)
831 {
832 
833 	return (0);
834 }
835 
836 /*
837  * Unmount the filesystem described by mp.
838  */
839 int
840 msdosfs_unmount(mp, mntflags)
841 	struct mount *mp;
842 	int mntflags;
843 {
844 	struct msdosfsmount *pmp;
845 	int error, flags;
846 
847 	flags = 0;
848 	if (mntflags & MNT_FORCE)
849 		flags |= FORCECLOSE;
850 #ifdef QUOTA
851 #endif
852 	if ((error = vflush(mp, NULLVP, flags)) != 0)
853 		return (error);
854 	pmp = VFSTOMSDOSFS(mp);
855 	if (pmp->pm_devvp->v_type != VBAD)
856 		pmp->pm_devvp->v_specmountpoint = NULL;
857 #ifdef MSDOSFS_DEBUG
858 	{
859 		struct vnode *vp = pmp->pm_devvp;
860 
861 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
862 		printf("flag %08x, usecount %d, writecount %d, holdcnt %d\n",
863 		    vp->v_vflag | vp->v_iflag | vp->v_uflag, vp->v_usecount,
864 		    vp->v_writecount, vp->v_holdcnt);
865 		printf("mount %p, op %p\n",
866 		    vp->v_mount, vp->v_op);
867 		printf("freef %p, freeb %p, mount %p\n",
868 		    vp->v_freelist.tqe_next, vp->v_freelist.tqe_prev,
869 		    vp->v_mount);
870 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %d, type %d\n",
871 		    vp->v_cleanblkhd.lh_first,
872 		    vp->v_dirtyblkhd.lh_first,
873 		    vp->v_numoutput, vp->v_type);
874 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
875 		    vp->v_socket, vp->v_tag,
876 		    ((u_int *)vp->v_data)[0],
877 		    ((u_int *)vp->v_data)[1]);
878 	}
879 #endif
880 	vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
881 	error = VOP_CLOSE(pmp->pm_devvp,
882 	    pmp->pm_flags & MSDOSFSMNT_RONLY ? FREAD : FREAD|FWRITE, NOCRED);
883 	vput(pmp->pm_devvp);
884 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
885 	free(pmp, M_MSDOSFSMNT);
886 	mp->mnt_data = NULL;
887 	mp->mnt_flag &= ~MNT_LOCAL;
888 	return (error);
889 }
890 
891 int
892 msdosfs_root(mp, vpp)
893 	struct mount *mp;
894 	struct vnode **vpp;
895 {
896 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
897 	struct denode *ndep;
898 	int error;
899 
900 #ifdef MSDOSFS_DEBUG
901 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
902 #endif
903 	if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0)
904 		return (error);
905 	*vpp = DETOV(ndep);
906 	return (0);
907 }
908 
909 int
910 msdosfs_statvfs(struct mount *mp, struct statvfs *sbp)
911 {
912 	struct msdosfsmount *pmp;
913 
914 	pmp = VFSTOMSDOSFS(mp);
915 	sbp->f_bsize = pmp->pm_bpcluster;
916 	sbp->f_frsize = sbp->f_bsize;
917 	sbp->f_iosize = pmp->pm_bpcluster;
918 	sbp->f_blocks = pmp->pm_nmbrofclusters;
919 	sbp->f_bfree = pmp->pm_freeclustercount;
920 	sbp->f_bavail = pmp->pm_freeclustercount;
921 	sbp->f_bresvd = 0;
922 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
923 	sbp->f_ffree = 0;	/* what to put in here? */
924 	sbp->f_favail = 0;	/* what to put in here? */
925 	sbp->f_fresvd = 0;
926 	copy_statvfs_info(sbp, mp);
927 	return (0);
928 }
929 
930 int
931 msdosfs_sync(mp, waitfor, cred)
932 	struct mount *mp;
933 	int waitfor;
934 	kauth_cred_t cred;
935 {
936 	struct vnode *vp, *mvp;
937 	struct denode *dep;
938 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
939 	int error, allerror = 0;
940 
941 	/*
942 	 * If we ever switch to not updating all of the fats all the time,
943 	 * this would be the place to update them from the first one.
944 	 */
945 	if (pmp->pm_fmod != 0) {
946 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
947 			panic("msdosfs_sync: rofs mod");
948 		else {
949 			/* update fats here */
950 		}
951 	}
952 	/* Allocate a marker vnode. */
953 	if ((mvp = vnalloc(mp)) == NULL)
954 		return ENOMEM;
955 	/*
956 	 * Write back each (modified) denode.
957 	 */
958 	mutex_enter(&mntvnode_lock);
959 loop:
960 	for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp; vp = vunmark(mvp)) {
961 		vmark(mvp, vp);
962 		if (vp->v_mount != mp || vismarker(vp))
963 			continue;
964 		mutex_enter(&vp->v_interlock);
965 		dep = VTODE(vp);
966 		if (waitfor == MNT_LAZY || vp->v_type == VNON ||
967 		    (((dep->de_flag &
968 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0) &&
969 		     (LIST_EMPTY(&vp->v_dirtyblkhd) &&
970 		      UVM_OBJ_IS_CLEAN(&vp->v_uobj)))) {
971 			mutex_exit(&vp->v_interlock);
972 			continue;
973 		}
974 		mutex_exit(&mntvnode_lock);
975 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK);
976 		if (error) {
977 			mutex_enter(&mntvnode_lock);
978 			if (error == ENOENT) {
979 				(void)vunmark(mvp);
980 				goto loop;
981 			}
982 			continue;
983 		}
984 		if ((error = VOP_FSYNC(vp, cred,
985 		    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0)) != 0)
986 			allerror = error;
987 		vput(vp);
988 		mutex_enter(&mntvnode_lock);
989 	}
990 	mutex_exit(&mntvnode_lock);
991 	vnfree(mvp);
992 
993 	/*
994 	 * Force stale file system control information to be flushed.
995 	 */
996 	if ((error = VOP_FSYNC(pmp->pm_devvp, cred,
997 	    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0)) != 0)
998 		allerror = error;
999 #ifdef QUOTA
1000 	/* qsync(mp); */
1001 #endif
1002 	return (allerror);
1003 }
1004 
1005 int
1006 msdosfs_fhtovp(mp, fhp, vpp)
1007 	struct mount *mp;
1008 	struct fid *fhp;
1009 	struct vnode **vpp;
1010 {
1011 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
1012 	struct defid defh;
1013 	struct denode *dep;
1014 	int error;
1015 
1016 	if (fhp->fid_len != sizeof(struct defid)) {
1017 		DPRINTF(("fid_len %d %zd\n", fhp->fid_len,
1018 		    sizeof(struct defid)));
1019 		return EINVAL;
1020 	}
1021 
1022 	memcpy(&defh, fhp, sizeof(defh));
1023 	error = deget(pmp, defh.defid_dirclust, defh.defid_dirofs, &dep);
1024 	if (error) {
1025 		DPRINTF(("deget %d\n", error));
1026 		*vpp = NULLVP;
1027 		return (error);
1028 	}
1029 	*vpp = DETOV(dep);
1030 	return (0);
1031 }
1032 
1033 int
1034 msdosfs_vptofh(vp, fhp, fh_size)
1035 	struct vnode *vp;
1036 	struct fid *fhp;
1037 	size_t *fh_size;
1038 {
1039 	struct denode *dep;
1040 	struct defid defh;
1041 
1042 	if (*fh_size < sizeof(struct defid)) {
1043 		*fh_size = sizeof(struct defid);
1044 		return E2BIG;
1045 	}
1046 	*fh_size = sizeof(struct defid);
1047 	dep = VTODE(vp);
1048 	memset(&defh, 0, sizeof(defh));
1049 	defh.defid_len = sizeof(struct defid);
1050 	defh.defid_dirclust = dep->de_dirclust;
1051 	defh.defid_dirofs = dep->de_diroffset;
1052 	/* defh.defid_gen = dep->de_gen; */
1053 	memcpy(fhp, &defh, sizeof(defh));
1054 	return (0);
1055 }
1056 
1057 int
1058 msdosfs_vget(struct mount *mp, ino_t ino,
1059     struct vnode **vpp)
1060 {
1061 
1062 	return (EOPNOTSUPP);
1063 }
1064 
1065 SYSCTL_SETUP(sysctl_vfs_msdosfs_setup, "sysctl vfs.msdosfs subtree setup")
1066 {
1067 
1068 	sysctl_createv(clog, 0, NULL, NULL,
1069 		       CTLFLAG_PERMANENT,
1070 		       CTLTYPE_NODE, "vfs", NULL,
1071 		       NULL, 0, NULL, 0,
1072 		       CTL_VFS, CTL_EOL);
1073 	sysctl_createv(clog, 0, NULL, NULL,
1074 		       CTLFLAG_PERMANENT,
1075 		       CTLTYPE_NODE, "msdosfs",
1076 		       SYSCTL_DESCR("MS-DOS file system"),
1077 		       NULL, 0, NULL, 0,
1078 		       CTL_VFS, 4, CTL_EOL);
1079 	/*
1080 	 * XXX the "4" above could be dynamic, thereby eliminating one
1081 	 * more instance of the "number to vfs" mapping problem, but
1082 	 * "4" is the order as taken from sys/mount.h
1083 	 */
1084 }
1085