xref: /netbsd-src/sys/fs/msdosfs/msdosfs_vfsops.c (revision 404fbe5fb94ca1e054339640cabb2801ce52dd30)
1 /*	$NetBSD: msdosfs_vfsops.c,v 1.70 2008/12/26 03:38:52 jmcneill 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 1.70 2008/12/26 03:38:52 jmcneill Exp $");
52 
53 #if defined(_KERNEL_OPT)
54 #include "opt_compat_netbsd.h"
55 #endif
56 
57 #include <sys/param.h>
58 #include <sys/systm.h>
59 #include <sys/sysctl.h>
60 #include <sys/namei.h>
61 #include <sys/proc.h>
62 #include <sys/kernel.h>
63 #include <sys/vnode.h>
64 #include <miscfs/genfs/genfs.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/disk.h>
72 #include <sys/ioctl.h>
73 #include <sys/malloc.h>
74 #include <sys/dirent.h>
75 #include <sys/stat.h>
76 #include <sys/conf.h>
77 #include <sys/kauth.h>
78 #include <sys/module.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 MODULE(MODULE_CLASS_VFS, msdosfs, NULL);
88 
89 #ifdef MSDOSFS_DEBUG
90 #define DPRINTF(a) uprintf a
91 #else
92 #define DPRINTF(a)
93 #endif
94 
95 #define MSDOSFS_NAMEMAX(pmp) \
96 	(pmp)->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12
97 
98 VFS_PROTOS(msdosfs);
99 
100 int msdosfs_mountfs(struct vnode *, struct mount *, struct lwp *,
101     struct msdosfs_args *);
102 
103 static int update_mp(struct mount *, struct msdosfs_args *);
104 
105 MALLOC_JUSTDEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOS FS mount structure");
106 MALLOC_JUSTDEFINE(M_MSDOSFSFAT, "MSDOSFS fat", "MSDOS FS fat table");
107 MALLOC_JUSTDEFINE(M_MSDOSFSTMP, "MSDOSFS temp", "MSDOS FS temp. structures");
108 
109 #define ROOTNAME "root_device"
110 
111 static struct sysctllog *msdosfs_sysctl_log;
112 
113 extern const struct vnodeopv_desc msdosfs_vnodeop_opv_desc;
114 
115 const struct vnodeopv_desc * const msdosfs_vnodeopv_descs[] = {
116 	&msdosfs_vnodeop_opv_desc,
117 	NULL,
118 };
119 
120 struct vfsops msdosfs_vfsops = {
121 	MOUNT_MSDOS,
122 	sizeof (struct msdosfs_args),
123 	msdosfs_mount,
124 	msdosfs_start,
125 	msdosfs_unmount,
126 	msdosfs_root,
127 	(void *)eopnotsupp,		/* vfs_quotactl */
128 	msdosfs_statvfs,
129 	msdosfs_sync,
130 	msdosfs_vget,
131 	msdosfs_fhtovp,
132 	msdosfs_vptofh,
133 	msdosfs_init,
134 	msdosfs_reinit,
135 	msdosfs_done,
136 	msdosfs_mountroot,
137 	(int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
138 	vfs_stdextattrctl,
139 	(void *)eopnotsupp,		/* vfs_suspendctl */
140 	genfs_renamelock_enter,
141 	genfs_renamelock_exit,
142 	(void *)eopnotsupp,
143 	msdosfs_vnodeopv_descs,
144 	0,
145 	{ NULL, NULL },
146 };
147 
148 static int
149 msdosfs_modcmd(modcmd_t cmd, void *arg)
150 {
151 	int error;
152 
153 	switch (cmd) {
154 	case MODULE_CMD_INIT:
155 		error = vfs_attach(&msdosfs_vfsops);
156 		if (error != 0)
157 			break;
158 		sysctl_createv(&msdosfs_sysctl_log, 0, NULL, NULL,
159 			       CTLFLAG_PERMANENT,
160 			       CTLTYPE_NODE, "vfs", NULL,
161 			       NULL, 0, NULL, 0,
162 			       CTL_VFS, CTL_EOL);
163 		sysctl_createv(&msdosfs_sysctl_log, 0, NULL, NULL,
164 			       CTLFLAG_PERMANENT,
165 			       CTLTYPE_NODE, "msdosfs",
166 			       SYSCTL_DESCR("MS-DOS file system"),
167 			       NULL, 0, NULL, 0,
168 			       CTL_VFS, 4, CTL_EOL);
169 		/*
170 		 * XXX the "4" above could be dynamic, thereby eliminating one
171 		 * more instance of the "number to vfs" mapping problem, but
172 		 * "4" is the order as taken from sys/mount.h
173 		 */
174 		break;
175 	case MODULE_CMD_FINI:
176 		error = vfs_detach(&msdosfs_vfsops);
177 		if (error != 0)
178 			break;
179 		sysctl_teardown(&msdosfs_sysctl_log);
180 		break;
181 	default:
182 		error = ENOTTY;
183 		break;
184 	}
185 
186 	return (error);
187 }
188 
189 static int
190 update_mp(mp, argp)
191 	struct mount *mp;
192 	struct msdosfs_args *argp;
193 {
194 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
195 	int error;
196 
197 	pmp->pm_gid = argp->gid;
198 	pmp->pm_uid = argp->uid;
199 	pmp->pm_mask = argp->mask & ALLPERMS;
200 	pmp->pm_dirmask = argp->dirmask & ALLPERMS;
201 	pmp->pm_gmtoff = argp->gmtoff;
202 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
203 
204 	/*
205 	 * GEMDOS knows nothing (yet) about win95
206 	 */
207 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
208 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
209 
210 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
211 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
212 	else if (!(pmp->pm_flags &
213 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
214 		struct vnode *rtvp;
215 
216 		/*
217 		 * Try to divine whether to support Win'95 long filenames
218 		 */
219 		if (FAT32(pmp))
220 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
221 		else {
222 			if ((error = msdosfs_root(mp, &rtvp)) != 0)
223 				return error;
224 			pmp->pm_flags |= findwin95(VTODE(rtvp))
225 				? MSDOSFSMNT_LONGNAME
226 					: MSDOSFSMNT_SHORTNAME;
227 			vput(rtvp);
228 		}
229 	}
230 
231 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
232 
233 	return 0;
234 }
235 
236 int
237 msdosfs_mountroot()
238 {
239 	struct mount *mp;
240 	struct lwp *l = curlwp;	/* XXX */
241 	int error;
242 	struct msdosfs_args args;
243 
244 	if (device_class(root_device) != DV_DISK)
245 		return (ENODEV);
246 
247 	if ((error = vfs_rootmountalloc(MOUNT_MSDOS, "root_device", &mp))) {
248 		vrele(rootvp);
249 		return (error);
250 	}
251 
252 	args.flags = MSDOSFSMNT_VERSIONED;
253 	args.uid = 0;
254 	args.gid = 0;
255 	args.mask = 0777;
256 	args.version = MSDOSFSMNT_VERSION;
257 	args.dirmask = 0777;
258 
259 	if ((error = msdosfs_mountfs(rootvp, mp, l, &args)) != 0) {
260 		vfs_unbusy(mp, false, NULL);
261 		vfs_destroy(mp);
262 		return (error);
263 	}
264 
265 	if ((error = update_mp(mp, &args)) != 0) {
266 		(void)msdosfs_unmount(mp, 0);
267 		vfs_unbusy(mp, false, NULL);
268 		vfs_destroy(mp);
269 		vrele(rootvp);
270 		return (error);
271 	}
272 
273 	mutex_enter(&mountlist_lock);
274 	CIRCLEQ_INSERT_TAIL(&mountlist, mp, mnt_list);
275 	mutex_exit(&mountlist_lock);
276 	(void)msdosfs_statvfs(mp, &mp->mnt_stat);
277 	vfs_unbusy(mp, false, NULL);
278 	return (0);
279 }
280 
281 /*
282  * mp - path - addr in user space of mount point (ie /usr or whatever)
283  * data - addr in user space of mount params including the name of the block
284  * special file to treat as a filesystem.
285  */
286 int
287 msdosfs_mount(mp, path, data, data_len)
288 	struct mount *mp;
289 	const char *path;
290 	void *data;
291 	size_t *data_len;
292 {
293 	struct lwp *l = curlwp;
294 	struct nameidata nd;
295 	struct vnode *devvp;	  /* vnode for blk device to mount */
296 	struct msdosfs_args *args = data; /* holds data from mount request */
297 	/* msdosfs specific mount control block */
298 	struct msdosfsmount *pmp = NULL;
299 	int error, flags;
300 	mode_t accessmode;
301 
302 	if (*data_len < sizeof *args)
303 		return EINVAL;
304 
305 	if (mp->mnt_flag & MNT_GETARGS) {
306 		pmp = VFSTOMSDOSFS(mp);
307 		if (pmp == NULL)
308 			return EIO;
309 		args->fspec = NULL;
310 		args->uid = pmp->pm_uid;
311 		args->gid = pmp->pm_gid;
312 		args->mask = pmp->pm_mask;
313 		args->flags = pmp->pm_flags;
314 		args->version = MSDOSFSMNT_VERSION;
315 		args->dirmask = pmp->pm_dirmask;
316 		args->gmtoff = pmp->pm_gmtoff;
317 		*data_len = sizeof *args;
318 		return 0;
319 	}
320 
321 	/*
322 	 * If not versioned (i.e. using old mount_msdos(8)), fill in
323 	 * the additional structure items with suitable defaults.
324 	 */
325 	if ((args->flags & MSDOSFSMNT_VERSIONED) == 0) {
326 		args->version = 1;
327 		args->dirmask = args->mask;
328 	}
329 
330 	/*
331 	 * Reset GMT offset for pre-v3 mount structure args.
332 	 */
333 	if (args->version < 3)
334 		args->gmtoff = 0;
335 
336 	/*
337 	 * If updating, check whether changing from read-only to
338 	 * read/write; if there is no device name, that's all we do.
339 	 */
340 	if (mp->mnt_flag & MNT_UPDATE) {
341 		pmp = VFSTOMSDOSFS(mp);
342 		error = 0;
343 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
344 			flags = WRITECLOSE;
345 			if (mp->mnt_flag & MNT_FORCE)
346 				flags |= FORCECLOSE;
347 			error = vflush(mp, NULLVP, flags);
348 		}
349 		if (!error && (mp->mnt_flag & MNT_RELOAD))
350 			/* not yet implemented */
351 			error = EOPNOTSUPP;
352 		if (error) {
353 			DPRINTF(("vflush %d\n", error));
354 			return (error);
355 		}
356 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_iflag & IMNT_WANTRDWR)) {
357 			/*
358 			 * If upgrade to read-write by non-root, then verify
359 			 * that user has necessary permissions on the device.
360 			 */
361 			if (kauth_authorize_generic(l->l_cred,
362 			    KAUTH_GENERIC_ISSUSER, NULL) != 0) {
363 				devvp = pmp->pm_devvp;
364 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
365 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
366 						   l->l_cred);
367 				VOP_UNLOCK(devvp, 0);
368 				DPRINTF(("VOP_ACCESS %d\n", error));
369 				if (error)
370 					return (error);
371 			}
372 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
373 		}
374 		if (args->fspec == NULL) {
375 			DPRINTF(("missing fspec\n"));
376 			return EINVAL;
377 		}
378 	}
379 	/*
380 	 * Not an update, or updating the name: look up the name
381 	 * and verify that it refers to a sensible block device.
382 	 */
383 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, args->fspec);
384 	if ((error = namei(&nd)) != 0) {
385 		DPRINTF(("namei %d\n", error));
386 		return (error);
387 	}
388 	devvp = nd.ni_vp;
389 
390 	if (devvp->v_type != VBLK) {
391 		DPRINTF(("not block\n"));
392 		vrele(devvp);
393 		return (ENOTBLK);
394 	}
395 	if (bdevsw_lookup(devvp->v_rdev) == NULL) {
396 		DPRINTF(("no block switch\n"));
397 		vrele(devvp);
398 		return (ENXIO);
399 	}
400 	/*
401 	 * If mount by non-root, then verify that user has necessary
402 	 * permissions on the device.
403 	 */
404 	if (kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER, NULL) != 0) {
405 		accessmode = VREAD;
406 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
407 			accessmode |= VWRITE;
408 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
409 		error = VOP_ACCESS(devvp, accessmode, l->l_cred);
410 		VOP_UNLOCK(devvp, 0);
411 		if (error) {
412 			DPRINTF(("VOP_ACCESS2 %d\n", error));
413 			vrele(devvp);
414 			return (error);
415 		}
416 	}
417 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
418 		int xflags;
419 
420 		if (mp->mnt_flag & MNT_RDONLY)
421 			xflags = FREAD;
422 		else
423 			xflags = FREAD|FWRITE;
424 		error = VOP_OPEN(devvp, xflags, FSCRED);
425 		if (error) {
426 			DPRINTF(("VOP_OPEN %d\n", error));
427 			goto fail;
428 		}
429 		error = msdosfs_mountfs(devvp, mp, l, args);
430 		if (error) {
431 			DPRINTF(("msdosfs_mountfs %d\n", error));
432 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
433 			(void) VOP_CLOSE(devvp, xflags, NOCRED);
434 			VOP_UNLOCK(devvp, 0);
435 			goto fail;
436 		}
437 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
438 		pmp = VFSTOMSDOSFS(mp);
439 #endif
440 	} else {
441 		vrele(devvp);
442 		if (devvp != pmp->pm_devvp) {
443 			DPRINTF(("devvp %p pmp %p\n",
444 			    devvp, pmp->pm_devvp));
445 			return (EINVAL);	/* needs translation */
446 		}
447 	}
448 	if ((error = update_mp(mp, args)) != 0) {
449 		msdosfs_unmount(mp, MNT_FORCE);
450 		DPRINTF(("update_mp %d\n", error));
451 		return error;
452 	}
453 
454 #ifdef MSDOSFS_DEBUG
455 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
456 #endif
457 	return set_statvfs_info(path, UIO_USERSPACE, args->fspec, UIO_USERSPACE,
458 	    mp->mnt_op->vfs_name, mp, l);
459 
460 fail:
461 	vrele(devvp);
462 	return (error);
463 }
464 
465 int
466 msdosfs_mountfs(devvp, mp, l, argp)
467 	struct vnode *devvp;
468 	struct mount *mp;
469 	struct lwp *l;
470 	struct msdosfs_args *argp;
471 {
472 	struct msdosfsmount *pmp;
473 	struct buf *bp;
474 	dev_t dev = devvp->v_rdev;
475 	struct partinfo dpart;
476 	union bootsector *bsp;
477 	struct byte_bpb33 *b33;
478 	struct byte_bpb50 *b50;
479 	struct byte_bpb710 *b710;
480 	u_int8_t SecPerClust;
481 	int	ronly, error, tmp;
482 	int	bsize, dtype, fstype, secsize;
483 	u_int64_t psize;
484 
485 	/* Flush out any old buffers remaining from a previous use. */
486 	if ((error = vinvalbuf(devvp, V_SAVE, l->l_cred, l, 0, 0)) != 0)
487 		return (error);
488 
489 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
490 
491 	bp  = NULL; /* both used in error_exit */
492 	pmp = NULL;
493 
494 	/*
495  	 * We need the disklabel to calculate the size of a FAT entry
496 	 * later on. Also make sure the partition contains a filesystem
497 	 * of type FS_MSDOS. This doesn't work for floppies, so we have
498 	 * to check for them too.
499  	 *
500  	 * There might still be parts of the msdos fs driver which assume
501 	 * that the size of a disk block will always be 512 bytes.
502 	 * Let's root them out...
503 	 */
504 	error = VOP_IOCTL(devvp, DIOCGPART, &dpart, FREAD, NOCRED);
505 	if (error == 0) {
506 		secsize = dpart.disklab->d_secsize;
507 		dtype = dpart.disklab->d_type;
508 		fstype = dpart.part->p_fstype;
509 		psize = dpart.part->p_size;
510 	} else {
511 		struct dkwedge_info dkw;
512 		error = VOP_IOCTL(devvp, DIOCGWEDGEINFO, &dkw, FREAD, NOCRED);
513 		secsize = 512;	/* XXX */
514 		dtype = DTYPE_FLOPPY; /* XXX */
515 		fstype = FS_MSDOS;
516 		psize = -1;
517 		if (error) {
518 			if (error != ENOTTY) {
519 				DPRINTF(("Error getting partition info %d\n",
520 				    error));
521 				goto error_exit;
522 			}
523 		} else {
524 			fstype = strcmp(dkw.dkw_ptype, DKW_PTYPE_FAT) == 0 ?
525 			    FS_MSDOS : -1;
526 			psize = dkw.dkw_size;
527 		}
528 	}
529 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
530 		bsize = secsize;
531 		if (bsize != 512 ||
532 		    (dtype != DTYPE_FLOPPY && fstype != FS_MSDOS)) {
533 			DPRINTF(("bsize %d dtype %d fstype %d\n", bsize, dtype,
534 			    fstype));
535 			error = EINVAL;
536 			goto error_exit;
537 		}
538 	} else
539 		bsize = 0;
540 
541 	/*
542 	 * Read the boot sector of the filesystem, and then check the
543 	 * boot signature.  If not a dos boot sector then error out.
544 	 */
545 	if ((error = bread(devvp, 0, secsize, NOCRED, 0, &bp)) != 0)
546 		goto error_exit;
547 	bsp = (union bootsector *)bp->b_data;
548 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
549 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
550 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
551 
552 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
553 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
554 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
555 			DPRINTF(("bootsig0 %d bootsig1 %d\n",
556 			    bsp->bs50.bsBootSectSig0,
557 			    bsp->bs50.bsBootSectSig1));
558 			error = EINVAL;
559 			goto error_exit;
560 		}
561 	}
562 
563 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK);
564 	memset(pmp, 0, sizeof *pmp);
565 	pmp->pm_mountp = mp;
566 
567 	/*
568 	 * Compute several useful quantities from the bpb in the
569 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
570 	 * the fields that are different between dos 5 and dos 3.3.
571 	 */
572 	SecPerClust = b50->bpbSecPerClust;
573 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
574 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
575 	pmp->pm_FATs = b50->bpbFATs;
576 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
577 	pmp->pm_Sectors = getushort(b50->bpbSectors);
578 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
579 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
580 	pmp->pm_Heads = getushort(b50->bpbHeads);
581 	pmp->pm_Media = b50->bpbMedia;
582 
583 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
584 		/* XXX - We should probably check more values here */
585     		if (!pmp->pm_BytesPerSec || !SecPerClust
586 	    		|| pmp->pm_SecPerTrack > 63) {
587 			DPRINTF(("bytespersec %d secperclust %d "
588 			    "secpertrack %d\n",
589 			    pmp->pm_BytesPerSec, SecPerClust,
590 			    pmp->pm_SecPerTrack));
591 			error = EINVAL;
592 			goto error_exit;
593 		}
594 	}
595 
596 	if (pmp->pm_Sectors == 0) {
597 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
598 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
599 	} else {
600 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
601 		pmp->pm_HugeSectors = pmp->pm_Sectors;
602 	}
603 
604 	if (pmp->pm_RootDirEnts == 0) {
605 		unsigned short vers = getushort(b710->bpbFSVers);
606 		/*
607 		 * Some say that bsBootSectSig[23] must be zero, but
608 		 * Windows does not require this and some digital cameras
609 		 * do not set these to zero.  Therefore, do not insist.
610 		 */
611 		if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) {
612 			DPRINTF(("sectors %d fatsecs %lu vers %d\n",
613 			    pmp->pm_Sectors, pmp->pm_FATsecs, vers));
614 			error = EINVAL;
615 			goto error_exit;
616 		}
617 		pmp->pm_fatmask = FAT32_MASK;
618 		pmp->pm_fatmult = 4;
619 		pmp->pm_fatdiv = 1;
620 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
621 
622 		/* mirrorring is enabled if the FATMIRROR bit is not set */
623 		if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
624 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
625 		else
626 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
627 	} else
628 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
629 
630 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
631 		if (FAT32(pmp)) {
632 			DPRINTF(("fat32 for gemdos\n"));
633 			/*
634 			 * GEMDOS doesn't know fat32.
635 			 */
636 			error = EINVAL;
637 			goto error_exit;
638 		}
639 
640 		/*
641 		 * Check a few values (could do some more):
642 		 * - logical sector size: power of 2, >= block size
643 		 * - sectors per cluster: power of 2, >= 1
644 		 * - number of sectors:   >= 1, <= size of partition
645 		 */
646 		if ( (SecPerClust == 0)
647 		  || (SecPerClust & (SecPerClust - 1))
648 		  || (pmp->pm_BytesPerSec < bsize)
649 		  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
650 		  || (pmp->pm_HugeSectors == 0)
651 		  || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize)
652 		      > psize)) {
653 			DPRINTF(("consistency checks for gemdos\n"));
654 			error = EINVAL;
655 			goto error_exit;
656 		}
657 		/*
658 		 * XXX - Many parts of the msdos fs driver seem to assume that
659 		 * the number of bytes per logical sector (BytesPerSec) will
660 		 * always be the same as the number of bytes per disk block
661 		 * Let's pretend it is.
662 		 */
663 		tmp = pmp->pm_BytesPerSec / bsize;
664 		pmp->pm_BytesPerSec  = bsize;
665 		pmp->pm_HugeSectors *= tmp;
666 		pmp->pm_HiddenSects *= tmp;
667 		pmp->pm_ResSectors  *= tmp;
668 		pmp->pm_Sectors     *= tmp;
669 		pmp->pm_FATsecs     *= tmp;
670 		SecPerClust         *= tmp;
671 	}
672 
673 	/* Check that fs has nonzero FAT size */
674 	if (pmp->pm_FATsecs == 0) {
675 		DPRINTF(("FATsecs is 0\n"));
676 		error = EINVAL;
677 		goto error_exit;
678 	}
679 
680 	pmp->pm_fatblk = pmp->pm_ResSectors;
681 	if (FAT32(pmp)) {
682 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
683 		pmp->pm_firstcluster = pmp->pm_fatblk
684 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
685 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
686 	} else {
687 		pmp->pm_rootdirblk = pmp->pm_fatblk +
688 			(pmp->pm_FATs * pmp->pm_FATsecs);
689 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
690 				       + pmp->pm_BytesPerSec - 1)
691 			/ pmp->pm_BytesPerSec;/* in sectors */
692 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
693 	}
694 
695 	pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
696 	    SecPerClust;
697 	pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
698 	pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
699 
700 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
701 		if (pmp->pm_nmbrofclusters <= (0xff0 - 2)
702 		      && (dtype == DTYPE_FLOPPY
703 			  || (dtype == DTYPE_VND
704 				&& (pmp->pm_Heads == 1 || pmp->pm_Heads == 2)))
705 		    ) {
706 			pmp->pm_fatmask = FAT12_MASK;
707 			pmp->pm_fatmult = 3;
708 			pmp->pm_fatdiv = 2;
709 		} else {
710 			pmp->pm_fatmask = FAT16_MASK;
711 			pmp->pm_fatmult = 2;
712 			pmp->pm_fatdiv = 1;
713 		}
714 	} else if (pmp->pm_fatmask == 0) {
715 		if (pmp->pm_maxcluster
716 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
717 			/*
718 			 * This will usually be a floppy disk. This size makes
719 			 * sure that one fat entry will not be split across
720 			 * multiple blocks.
721 			 */
722 			pmp->pm_fatmask = FAT12_MASK;
723 			pmp->pm_fatmult = 3;
724 			pmp->pm_fatdiv = 2;
725 		} else {
726 			pmp->pm_fatmask = FAT16_MASK;
727 			pmp->pm_fatmult = 2;
728 			pmp->pm_fatdiv = 1;
729 		}
730 	}
731 	if (FAT12(pmp))
732 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
733 	else
734 		pmp->pm_fatblocksize = MAXBSIZE;
735 
736 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
737 	pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
738 
739 	/*
740 	 * Compute mask and shift value for isolating cluster relative byte
741 	 * offsets and cluster numbers from a file offset.
742 	 */
743 	pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
744 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
745 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
746 
747 	/*
748 	 * Check for valid cluster size
749 	 * must be a power of 2
750 	 */
751 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
752 		DPRINTF(("bpcluster %lu cnshift %lu\n",
753 		    pmp->pm_bpcluster, pmp->pm_cnshift));
754 		error = EINVAL;
755 		goto error_exit;
756 	}
757 
758 	/*
759 	 * Release the bootsector buffer.
760 	 */
761 	brelse(bp, BC_AGE);
762 	bp = NULL;
763 
764 	/*
765 	 * Check FSInfo.
766 	 */
767 	if (pmp->pm_fsinfo) {
768 		struct fsinfo *fp;
769 
770 		/*
771 		 * XXX	If the fsinfo block is stored on media with
772 		 *	2KB or larger sectors, is the fsinfo structure
773 		 *	padded at the end or in the middle?
774 		 */
775 		if ((error = bread(devvp, de_bn2kb(pmp, pmp->pm_fsinfo),
776 		    pmp->pm_BytesPerSec, NOCRED, 0, &bp)) != 0)
777 			goto error_exit;
778 		fp = (struct fsinfo *)bp->b_data;
779 		if (!memcmp(fp->fsisig1, "RRaA", 4)
780 		    && !memcmp(fp->fsisig2, "rrAa", 4)
781 		    && !memcmp(fp->fsisig3, "\0\0\125\252", 4)
782 		    && !memcmp(fp->fsisig4, "\0\0\125\252", 4))
783 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
784 		else
785 			pmp->pm_fsinfo = 0;
786 		brelse(bp, 0);
787 		bp = NULL;
788 	}
789 
790 	/*
791 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
792 	 * XXX
793 	 */
794 	if (pmp->pm_fsinfo) {
795 		if (pmp->pm_nxtfree == (u_long)-1)
796 			pmp->pm_fsinfo = 0;
797 	}
798 
799 	/*
800 	 * Allocate memory for the bitmap of allocated clusters, and then
801 	 * fill it in.
802 	 */
803 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
804 				   / N_INUSEBITS)
805 				  * sizeof(*pmp->pm_inusemap),
806 				  M_MSDOSFSFAT, M_WAITOK);
807 
808 	/*
809 	 * fillinusemap() needs pm_devvp.
810 	 */
811 	pmp->pm_dev = dev;
812 	pmp->pm_devvp = devvp;
813 
814 	/*
815 	 * Have the inuse map filled in.
816 	 */
817 	if ((error = fillinusemap(pmp)) != 0) {
818 		DPRINTF(("fillinusemap %d\n", error));
819 		goto error_exit;
820 	}
821 
822 	/*
823 	 * If they want fat updates to be synchronous then let them suffer
824 	 * the performance degradation in exchange for the on disk copy of
825 	 * the fat being correct just about all the time.  I suppose this
826 	 * would be a good thing to turn on if the kernel is still flakey.
827 	 */
828 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
829 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
830 
831 	/*
832 	 * Finish up.
833 	 */
834 	if (ronly)
835 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
836 	else
837 		pmp->pm_fmod = 1;
838 	mp->mnt_data = pmp;
839 	mp->mnt_stat.f_fsidx.__fsid_val[0] = (long)dev;
840 	mp->mnt_stat.f_fsidx.__fsid_val[1] = makefstype(MOUNT_MSDOS);
841 	mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
842 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
843 	mp->mnt_flag |= MNT_LOCAL;
844 	mp->mnt_dev_bshift = pmp->pm_bnshift;
845 	mp->mnt_fs_bshift = pmp->pm_cnshift;
846 
847 	/*
848 	 * If we ever do quotas for DOS filesystems this would be a place
849 	 * to fill in the info in the msdosfsmount structure. You dolt,
850 	 * quotas on dos filesystems make no sense because files have no
851 	 * owners on dos filesystems. of course there is some empty space
852 	 * in the directory entry where we could put uid's and gid's.
853 	 */
854 
855 	devvp->v_specmountpoint = mp;
856 
857 	return (0);
858 
859 error_exit:;
860 	if (bp)
861 		brelse(bp, BC_AGE);
862 	if (pmp) {
863 		if (pmp->pm_inusemap)
864 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
865 		free(pmp, M_MSDOSFSMNT);
866 		mp->mnt_data = NULL;
867 	}
868 	return (error);
869 }
870 
871 int
872 msdosfs_start(struct mount *mp, int flags)
873 {
874 
875 	return (0);
876 }
877 
878 /*
879  * Unmount the filesystem described by mp.
880  */
881 int
882 msdosfs_unmount(mp, mntflags)
883 	struct mount *mp;
884 	int mntflags;
885 {
886 	struct msdosfsmount *pmp;
887 	int error, flags;
888 
889 	flags = 0;
890 	if (mntflags & MNT_FORCE)
891 		flags |= FORCECLOSE;
892 	if ((error = vflush(mp, NULLVP, flags)) != 0)
893 		return (error);
894 	pmp = VFSTOMSDOSFS(mp);
895 	if (pmp->pm_devvp->v_type != VBAD)
896 		pmp->pm_devvp->v_specmountpoint = NULL;
897 #ifdef MSDOSFS_DEBUG
898 	{
899 		struct vnode *vp = pmp->pm_devvp;
900 
901 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
902 		printf("flag %08x, usecount %d, writecount %d, holdcnt %d\n",
903 		    vp->v_vflag | vp->v_iflag | vp->v_uflag, vp->v_usecount,
904 		    vp->v_writecount, vp->v_holdcnt);
905 		printf("mount %p, op %p\n",
906 		    vp->v_mount, vp->v_op);
907 		printf("freef %p, freeb %p, mount %p\n",
908 		    vp->v_freelist.tqe_next, vp->v_freelist.tqe_prev,
909 		    vp->v_mount);
910 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %d, type %d\n",
911 		    vp->v_cleanblkhd.lh_first,
912 		    vp->v_dirtyblkhd.lh_first,
913 		    vp->v_numoutput, vp->v_type);
914 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
915 		    vp->v_socket, vp->v_tag,
916 		    ((u_int *)vp->v_data)[0],
917 		    ((u_int *)vp->v_data)[1]);
918 	}
919 #endif
920 	vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
921 	error = VOP_CLOSE(pmp->pm_devvp,
922 	    pmp->pm_flags & MSDOSFSMNT_RONLY ? FREAD : FREAD|FWRITE, NOCRED);
923 	vput(pmp->pm_devvp);
924 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
925 	free(pmp, M_MSDOSFSMNT);
926 	mp->mnt_data = NULL;
927 	mp->mnt_flag &= ~MNT_LOCAL;
928 	return (error);
929 }
930 
931 int
932 msdosfs_root(mp, vpp)
933 	struct mount *mp;
934 	struct vnode **vpp;
935 {
936 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
937 	struct denode *ndep;
938 	int error;
939 
940 #ifdef MSDOSFS_DEBUG
941 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
942 #endif
943 	if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0)
944 		return (error);
945 	*vpp = DETOV(ndep);
946 	return (0);
947 }
948 
949 int
950 msdosfs_statvfs(struct mount *mp, struct statvfs *sbp)
951 {
952 	struct msdosfsmount *pmp;
953 
954 	pmp = VFSTOMSDOSFS(mp);
955 	sbp->f_bsize = pmp->pm_bpcluster;
956 	sbp->f_frsize = sbp->f_bsize;
957 	sbp->f_iosize = pmp->pm_bpcluster;
958 	sbp->f_blocks = pmp->pm_nmbrofclusters;
959 	sbp->f_bfree = pmp->pm_freeclustercount;
960 	sbp->f_bavail = pmp->pm_freeclustercount;
961 	sbp->f_bresvd = 0;
962 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
963 	sbp->f_ffree = 0;	/* what to put in here? */
964 	sbp->f_favail = 0;	/* what to put in here? */
965 	sbp->f_fresvd = 0;
966 	copy_statvfs_info(sbp, mp);
967 	return (0);
968 }
969 
970 int
971 msdosfs_sync(mp, waitfor, cred)
972 	struct mount *mp;
973 	int waitfor;
974 	kauth_cred_t cred;
975 {
976 	struct vnode *vp, *mvp;
977 	struct denode *dep;
978 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
979 	int error, allerror = 0;
980 
981 	/*
982 	 * If we ever switch to not updating all of the fats all the time,
983 	 * this would be the place to update them from the first one.
984 	 */
985 	if (pmp->pm_fmod != 0) {
986 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
987 			panic("msdosfs_sync: rofs mod");
988 		else {
989 			/* update fats here */
990 		}
991 	}
992 	/* Allocate a marker vnode. */
993 	if ((mvp = vnalloc(mp)) == NULL)
994 		return ENOMEM;
995 	/*
996 	 * Write back each (modified) denode.
997 	 */
998 	mutex_enter(&mntvnode_lock);
999 loop:
1000 	for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp; vp = vunmark(mvp)) {
1001 		vmark(mvp, vp);
1002 		if (vp->v_mount != mp || vismarker(vp))
1003 			continue;
1004 		mutex_enter(&vp->v_interlock);
1005 		dep = VTODE(vp);
1006 		if (waitfor == MNT_LAZY || vp->v_type == VNON ||
1007 		    (((dep->de_flag &
1008 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0) &&
1009 		     (LIST_EMPTY(&vp->v_dirtyblkhd) &&
1010 		      UVM_OBJ_IS_CLEAN(&vp->v_uobj)))) {
1011 			mutex_exit(&vp->v_interlock);
1012 			continue;
1013 		}
1014 		mutex_exit(&mntvnode_lock);
1015 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK);
1016 		if (error) {
1017 			mutex_enter(&mntvnode_lock);
1018 			if (error == ENOENT) {
1019 				(void)vunmark(mvp);
1020 				goto loop;
1021 			}
1022 			continue;
1023 		}
1024 		if ((error = VOP_FSYNC(vp, cred,
1025 		    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0)) != 0)
1026 			allerror = error;
1027 		vput(vp);
1028 		mutex_enter(&mntvnode_lock);
1029 	}
1030 	mutex_exit(&mntvnode_lock);
1031 	vnfree(mvp);
1032 
1033 	/*
1034 	 * Force stale file system control information to be flushed.
1035 	 */
1036 	if ((error = VOP_FSYNC(pmp->pm_devvp, cred,
1037 	    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0)) != 0)
1038 		allerror = error;
1039 	return (allerror);
1040 }
1041 
1042 int
1043 msdosfs_fhtovp(mp, fhp, vpp)
1044 	struct mount *mp;
1045 	struct fid *fhp;
1046 	struct vnode **vpp;
1047 {
1048 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
1049 	struct defid defh;
1050 	struct denode *dep;
1051 	int error;
1052 
1053 	if (fhp->fid_len != sizeof(struct defid)) {
1054 		DPRINTF(("fid_len %d %zd\n", fhp->fid_len,
1055 		    sizeof(struct defid)));
1056 		return EINVAL;
1057 	}
1058 
1059 	memcpy(&defh, fhp, sizeof(defh));
1060 	error = deget(pmp, defh.defid_dirclust, defh.defid_dirofs, &dep);
1061 	if (error) {
1062 		DPRINTF(("deget %d\n", error));
1063 		*vpp = NULLVP;
1064 		return (error);
1065 	}
1066 	*vpp = DETOV(dep);
1067 	return (0);
1068 }
1069 
1070 int
1071 msdosfs_vptofh(vp, fhp, fh_size)
1072 	struct vnode *vp;
1073 	struct fid *fhp;
1074 	size_t *fh_size;
1075 {
1076 	struct denode *dep;
1077 	struct defid defh;
1078 
1079 	if (*fh_size < sizeof(struct defid)) {
1080 		*fh_size = sizeof(struct defid);
1081 		return E2BIG;
1082 	}
1083 	*fh_size = sizeof(struct defid);
1084 	dep = VTODE(vp);
1085 	memset(&defh, 0, sizeof(defh));
1086 	defh.defid_len = sizeof(struct defid);
1087 	defh.defid_dirclust = dep->de_dirclust;
1088 	defh.defid_dirofs = dep->de_diroffset;
1089 	/* defh.defid_gen = dep->de_gen; */
1090 	memcpy(fhp, &defh, sizeof(defh));
1091 	return (0);
1092 }
1093 
1094 int
1095 msdosfs_vget(struct mount *mp, ino_t ino,
1096     struct vnode **vpp)
1097 {
1098 
1099 	return (EOPNOTSUPP);
1100 }
1101