xref: /minix3/sys/fs/msdosfs/msdosfs_vfsops.c (revision 0b98e8aad89f2bd4ba80b523d73cf29e9dd82ce1)
1 /*	$NetBSD: msdosfs_vfsops.c,v 1.103 2013/11/23 13:35:36 christos 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 1.103 2013/11/23 13:35:36 christos 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/fstrans.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 #include <sys/module.h>
80 
81 #include <fs/msdosfs/bpb.h>
82 #include <fs/msdosfs/bootsect.h>
83 #include <fs/msdosfs/direntry.h>
84 #include <fs/msdosfs/denode.h>
85 #include <fs/msdosfs/msdosfsmount.h>
86 #include <fs/msdosfs/fat.h>
87 
88 MODULE(MODULE_CLASS_VFS, msdos, NULL);
89 
90 #ifdef MSDOSFS_DEBUG
91 #define DPRINTF(a) uprintf a
92 #else
93 #define DPRINTF(a)
94 #endif
95 
96 #define MSDOSFS_NAMEMAX(pmp) \
97 	(pmp)->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12
98 
99 VFS_PROTOS(msdosfs);
100 
101 int msdosfs_mountfs(struct vnode *, struct mount *, struct lwp *,
102     struct msdosfs_args *);
103 
104 static int update_mp(struct mount *, struct msdosfs_args *);
105 
106 MALLOC_JUSTDEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOS FS mount structure");
107 MALLOC_JUSTDEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOS FS FAT table");
108 MALLOC_JUSTDEFINE(M_MSDOSFSTMP, "MSDOSFS temp", "MSDOS FS temp. structures");
109 
110 #define ROOTNAME "root_device"
111 
112 static struct sysctllog *msdosfs_sysctl_log;
113 
114 extern const struct vnodeopv_desc msdosfs_vnodeop_opv_desc;
115 
116 const struct vnodeopv_desc * const msdosfs_vnodeopv_descs[] = {
117 	&msdosfs_vnodeop_opv_desc,
118 	NULL,
119 };
120 
121 struct vfsops msdosfs_vfsops = {
122 	MOUNT_MSDOS,
123 	sizeof (struct msdosfs_args),
124 	msdosfs_mount,
125 	msdosfs_start,
126 	msdosfs_unmount,
127 	msdosfs_root,
128 	(void *)eopnotsupp,		/* vfs_quotactl */
129 	msdosfs_statvfs,
130 	msdosfs_sync,
131 	msdosfs_vget,
132 	msdosfs_fhtovp,
133 	msdosfs_vptofh,
134 	msdosfs_init,
135 	msdosfs_reinit,
136 	msdosfs_done,
137 	msdosfs_mountroot,
138 	(int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
139 	vfs_stdextattrctl,
140 	msdosfs_suspendctl,
141 	genfs_renamelock_enter,
142 	genfs_renamelock_exit,
143 	(void *)eopnotsupp,
144 	msdosfs_vnodeopv_descs,
145 	0,
146 	{ NULL, NULL },
147 };
148 
149 static int
150 msdos_modcmd(modcmd_t cmd, void *arg)
151 {
152 	int error;
153 
154 	switch (cmd) {
155 	case MODULE_CMD_INIT:
156 		error = vfs_attach(&msdosfs_vfsops);
157 		if (error != 0)
158 			break;
159 		sysctl_createv(&msdosfs_sysctl_log, 0, NULL, NULL,
160 			       CTLFLAG_PERMANENT,
161 			       CTLTYPE_NODE, "vfs", NULL,
162 			       NULL, 0, NULL, 0,
163 			       CTL_VFS, CTL_EOL);
164 		sysctl_createv(&msdosfs_sysctl_log, 0, NULL, NULL,
165 			       CTLFLAG_PERMANENT,
166 			       CTLTYPE_NODE, "msdosfs",
167 			       SYSCTL_DESCR("MS-DOS file system"),
168 			       NULL, 0, NULL, 0,
169 			       CTL_VFS, 4, CTL_EOL);
170 		/*
171 		 * XXX the "4" above could be dynamic, thereby eliminating one
172 		 * more instance of the "number to vfs" mapping problem, but
173 		 * "4" is the order as taken from sys/mount.h
174 		 */
175 		break;
176 	case MODULE_CMD_FINI:
177 		error = vfs_detach(&msdosfs_vfsops);
178 		if (error != 0)
179 			break;
180 		sysctl_teardown(&msdosfs_sysctl_log);
181 		break;
182 	default:
183 		error = ENOTTY;
184 		break;
185 	}
186 
187 	return (error);
188 }
189 
190 static int
191 update_mp(struct mount *mp, struct msdosfs_args *argp)
192 {
193 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
194 	int error;
195 
196 	pmp->pm_gid = argp->gid;
197 	pmp->pm_uid = argp->uid;
198 	pmp->pm_mask = argp->mask & ALLPERMS;
199 	pmp->pm_dirmask = argp->dirmask & ALLPERMS;
200 	pmp->pm_gmtoff = argp->gmtoff;
201 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
202 
203 	/*
204 	 * GEMDOS knows nothing about win95 long filenames
205 	 */
206 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
207 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
208 
209 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
210 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
211 	else if (!(pmp->pm_flags &
212 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
213 		struct vnode *rtvp;
214 
215 		/*
216 		 * Try to divine whether to support Win'95 long filenames
217 		 */
218 		if (FAT32(pmp))
219 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
220 		else {
221 			if ((error = msdosfs_root(mp, &rtvp)) != 0)
222 				return error;
223 			pmp->pm_flags |= findwin95(VTODE(rtvp))
224 				? MSDOSFSMNT_LONGNAME
225 					: MSDOSFSMNT_SHORTNAME;
226 			vput(rtvp);
227 		}
228 	}
229 
230 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
231 
232 	return 0;
233 }
234 
235 int
236 msdosfs_mountroot(void)
237 {
238 	struct mount *mp;
239 	struct lwp *l = curlwp;	/* XXX */
240 	int error;
241 	struct msdosfs_args args;
242 
243 	if (device_class(root_device) != DV_DISK)
244 		return (ENODEV);
245 
246 	if ((error = vfs_rootmountalloc(MOUNT_MSDOS, "root_device", &mp))) {
247 		vrele(rootvp);
248 		return (error);
249 	}
250 
251 	args.flags = MSDOSFSMNT_VERSIONED;
252 	args.uid = 0;
253 	args.gid = 0;
254 	args.mask = 0777;
255 	args.version = MSDOSFSMNT_VERSION;
256 	args.dirmask = 0777;
257 
258 	if ((error = msdosfs_mountfs(rootvp, mp, l, &args)) != 0) {
259 		vfs_unbusy(mp, false, NULL);
260 		vfs_destroy(mp);
261 		return (error);
262 	}
263 
264 	if ((error = update_mp(mp, &args)) != 0) {
265 		(void)msdosfs_unmount(mp, 0);
266 		vfs_unbusy(mp, false, NULL);
267 		vfs_destroy(mp);
268 		vrele(rootvp);
269 		return (error);
270 	}
271 
272 	mountlist_append(mp);
273 	(void)msdosfs_statvfs(mp, &mp->mnt_stat);
274 	vfs_unbusy(mp, false, NULL);
275 	return (0);
276 }
277 
278 /*
279  * mp - path - addr in user space of mount point (ie /usr or whatever)
280  * data - addr in user space of mount params including the name of the block
281  * special file to treat as a filesystem.
282  */
283 int
284 msdosfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
285 {
286 	struct lwp *l = curlwp;
287 	struct vnode *devvp;	  /* vnode for blk device to mount */
288 	struct msdosfs_args *args = data; /* holds data from mount request */
289 	/* msdosfs specific mount control block */
290 	struct msdosfsmount *pmp = NULL;
291 	int error, flags;
292 	mode_t accessmode;
293 
294 	if (*data_len < sizeof *args)
295 		return EINVAL;
296 
297 	if (mp->mnt_flag & MNT_GETARGS) {
298 		pmp = VFSTOMSDOSFS(mp);
299 		if (pmp == NULL)
300 			return EIO;
301 		args->fspec = NULL;
302 		args->uid = pmp->pm_uid;
303 		args->gid = pmp->pm_gid;
304 		args->mask = pmp->pm_mask;
305 		args->flags = pmp->pm_flags;
306 		args->version = MSDOSFSMNT_VERSION;
307 		args->dirmask = pmp->pm_dirmask;
308 		args->gmtoff = pmp->pm_gmtoff;
309 		*data_len = sizeof *args;
310 		return 0;
311 	}
312 
313 	/*
314 	 * If not versioned (i.e. using old mount_msdos(8)), fill in
315 	 * the additional structure items with suitable defaults.
316 	 */
317 	if ((args->flags & MSDOSFSMNT_VERSIONED) == 0) {
318 		args->version = 1;
319 		args->dirmask = args->mask;
320 	}
321 
322 	/*
323 	 * Reset GMT offset for pre-v3 mount structure args.
324 	 */
325 	if (args->version < 3)
326 		args->gmtoff = 0;
327 
328 	/*
329 	 * If updating, check whether changing from read-only to
330 	 * read/write; if there is no device name, that's all we do.
331 	 */
332 	if (mp->mnt_flag & MNT_UPDATE) {
333 		pmp = VFSTOMSDOSFS(mp);
334 		error = 0;
335 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) &&
336 		    (mp->mnt_flag & MNT_RDONLY)) {
337 			flags = WRITECLOSE;
338 			if (mp->mnt_flag & MNT_FORCE)
339 				flags |= FORCECLOSE;
340 			error = vflush(mp, NULLVP, flags);
341 		}
342 		if (!error && (mp->mnt_flag & MNT_RELOAD))
343 			/* not yet implemented */
344 			error = EOPNOTSUPP;
345 		if (error) {
346 			DPRINTF(("vflush %d\n", error));
347 			return (error);
348 		}
349 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) &&
350 		    (mp->mnt_iflag & IMNT_WANTRDWR)) {
351 			/*
352 			 * If upgrade to read-write by non-root, then verify
353 			 * that user has necessary permissions on the device.
354 			 *
355 			 * Permission to update a mount is checked higher, so
356 			 * here we presume updating the mount is okay (for
357 			 * example, as far as securelevel goes) which leaves us
358 			 * with the normal check.
359 			 */
360 			devvp = pmp->pm_devvp;
361 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
362 			error = kauth_authorize_system(l->l_cred,
363 			    KAUTH_SYSTEM_MOUNT, KAUTH_REQ_SYSTEM_MOUNT_DEVICE,
364 			    mp, devvp, KAUTH_ARG(VREAD | VWRITE));
365 			VOP_UNLOCK(devvp);
366 			DPRINTF(("KAUTH_REQ_SYSTEM_MOUNT_DEVICE %d\n", error));
367 			if (error)
368 				return (error);
369 
370 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
371 		}
372 		if (args->fspec == NULL) {
373 			DPRINTF(("missing fspec\n"));
374 			return EINVAL;
375 		}
376 	}
377 	/*
378 	 * Not an update, or updating the name: look up the name
379 	 * and verify that it refers to a sensible block device.
380 	 */
381 	error = namei_simple_user(args->fspec,
382 				NSM_FOLLOW_NOEMULROOT, &devvp);
383 	if (error != 0) {
384 		DPRINTF(("namei %d\n", error));
385 		return (error);
386 	}
387 
388 	if (devvp->v_type != VBLK) {
389 		DPRINTF(("not block\n"));
390 		vrele(devvp);
391 		return (ENOTBLK);
392 	}
393 	if (bdevsw_lookup(devvp->v_rdev) == NULL) {
394 		DPRINTF(("no block switch\n"));
395 		vrele(devvp);
396 		return (ENXIO);
397 	}
398 	/*
399 	 * If mount by non-root, then verify that user has necessary
400 	 * permissions on the device.
401 	 */
402 	accessmode = VREAD;
403 	if ((mp->mnt_flag & MNT_RDONLY) == 0)
404 		accessmode |= VWRITE;
405 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
406 	error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_MOUNT,
407 	    KAUTH_REQ_SYSTEM_MOUNT_DEVICE, mp, devvp, KAUTH_ARG(accessmode));
408 	VOP_UNLOCK(devvp);
409 	if (error) {
410 		DPRINTF(("KAUTH_REQ_SYSTEM_MOUNT_DEVICE %d\n", error));
411 		vrele(devvp);
412 		return (error);
413 	}
414 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
415 		int xflags;
416 
417 		if (mp->mnt_flag & MNT_RDONLY)
418 			xflags = FREAD;
419 		else
420 			xflags = FREAD|FWRITE;
421 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
422 		error = VOP_OPEN(devvp, xflags, FSCRED);
423 		VOP_UNLOCK(devvp);
424 		if (error) {
425 			DPRINTF(("VOP_OPEN %d\n", error));
426 			goto fail;
427 		}
428 		error = msdosfs_mountfs(devvp, mp, l, args);
429 		if (error) {
430 			DPRINTF(("msdosfs_mountfs %d\n", error));
431 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
432 			(void) VOP_CLOSE(devvp, xflags, NOCRED);
433 			VOP_UNLOCK(devvp);
434 			goto fail;
435 		}
436 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
437 		pmp = VFSTOMSDOSFS(mp);
438 #endif
439 	} else {
440 		vrele(devvp);
441 		if (devvp != pmp->pm_devvp) {
442 			DPRINTF(("devvp %p pmp %p\n",
443 			    devvp, pmp->pm_devvp));
444 			return (EINVAL);	/* needs translation */
445 		}
446 	}
447 	if ((error = update_mp(mp, args)) != 0) {
448 		msdosfs_unmount(mp, MNT_FORCE);
449 		DPRINTF(("update_mp %d\n", error));
450 		return error;
451 	}
452 
453 #ifdef MSDOSFS_DEBUG
454 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
455 #endif
456 	return set_statvfs_info(path, UIO_USERSPACE, args->fspec, UIO_USERSPACE,
457 	    mp->mnt_op->vfs_name, mp, l);
458 
459 fail:
460 	vrele(devvp);
461 	return (error);
462 }
463 
464 int
465 msdosfs_mountfs(struct vnode *devvp, struct mount *mp, struct lwp *l, struct msdosfs_args *argp)
466 {
467 	struct msdosfsmount *pmp;
468 	struct buf *bp;
469 	dev_t dev = devvp->v_rdev;
470 	union bootsector *bsp;
471 	struct byte_bpb33 *b33;
472 	struct byte_bpb50 *b50;
473 	struct byte_bpb710 *b710;
474 	uint8_t SecPerClust;
475 	int	ronly, error, tmp;
476 	int	bsize;
477 	uint64_t psize;
478 	unsigned secsize;
479 
480 	/* Flush out any old buffers remaining from a previous use. */
481 	if ((error = vinvalbuf(devvp, V_SAVE, l->l_cred, l, 0, 0)) != 0)
482 		return (error);
483 
484 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
485 
486 	bp  = NULL; /* both used in error_exit */
487 	pmp = NULL;
488 
489 	error = fstrans_mount(mp);
490 	if (error)
491 		goto error_exit;
492 
493 	error = getdisksize(devvp, &psize, &secsize);
494 	if (error) {
495 		if (argp->flags & MSDOSFSMNT_GEMDOSFS)
496 			goto error_exit;
497 
498 		/* ok, so it failed.  we most likely don't need the info */
499 		secsize = DEV_BSIZE;
500 		psize = 0;
501 		error = 0;
502 	}
503 
504 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
505 		bsize = secsize;
506 		if (bsize != 512) {
507 			DPRINTF(("Invalid block bsize %d for GEMDOS\n", bsize));
508 			error = EINVAL;
509 			goto error_exit;
510 		}
511 	} else
512 		bsize = 0;
513 
514 	/*
515 	 * Read the boot sector of the filesystem, and then check the
516 	 * boot signature.  If not a dos boot sector then error out.
517 	 */
518 	if ((error = bread(devvp, 0, secsize, NOCRED, 0, &bp)) != 0)
519 		goto error_exit;
520 	bsp = (union bootsector *)bp->b_data;
521 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
522 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
523 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
524 
525 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
526 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
527 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
528 			DPRINTF(("bootsig0 %d bootsig1 %d\n",
529 			    bsp->bs50.bsBootSectSig0,
530 			    bsp->bs50.bsBootSectSig1));
531 			error = EINVAL;
532 			goto error_exit;
533 		}
534 	}
535 
536 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK);
537 	memset(pmp, 0, sizeof *pmp);
538 	pmp->pm_mountp = mp;
539 
540 	/*
541 	 * Compute several useful quantities from the bpb in the
542 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
543 	 * the fields that are different between dos 5 and dos 3.3.
544 	 */
545 	SecPerClust = b50->bpbSecPerClust;
546 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
547 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
548 	pmp->pm_FATs = b50->bpbFATs;
549 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
550 	pmp->pm_Sectors = getushort(b50->bpbSectors);
551 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
552 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
553 	pmp->pm_Heads = getushort(b50->bpbHeads);
554 	pmp->pm_Media = b50->bpbMedia;
555 
556 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
557 		/* XXX - We should probably check more values here */
558     		if (!pmp->pm_BytesPerSec || !SecPerClust
559 	    		|| pmp->pm_SecPerTrack > 63) {
560 			DPRINTF(("bytespersec %d secperclust %d "
561 			    "secpertrack %d\n",
562 			    pmp->pm_BytesPerSec, SecPerClust,
563 			    pmp->pm_SecPerTrack));
564 			error = EINVAL;
565 			goto error_exit;
566 		}
567 	}
568 
569 	if (pmp->pm_Sectors == 0) {
570 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
571 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
572 	} else {
573 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
574 		pmp->pm_HugeSectors = pmp->pm_Sectors;
575 	}
576 
577 	if (pmp->pm_RootDirEnts == 0) {
578 		unsigned short vers = getushort(b710->bpbFSVers);
579 		/*
580 		 * Some say that bsBootSectSig[23] must be zero, but
581 		 * Windows does not require this and some digital cameras
582 		 * do not set these to zero.  Therefore, do not insist.
583 		 */
584 		if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) {
585 			DPRINTF(("sectors %d fatsecs %lu vers %d\n",
586 			    pmp->pm_Sectors, pmp->pm_FATsecs, vers));
587 			error = EINVAL;
588 			goto error_exit;
589 		}
590 		pmp->pm_fatmask = FAT32_MASK;
591 		pmp->pm_fatmult = 4;
592 		pmp->pm_fatdiv = 1;
593 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
594 
595 		/* mirrorring is enabled if the FATMIRROR bit is not set */
596 		if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
597 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
598 		else
599 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
600 	} else
601 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
602 
603 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
604 		if (FAT32(pmp)) {
605 			DPRINTF(("FAT32 for GEMDOS\n"));
606 			/*
607 			 * GEMDOS doesn't know FAT32.
608 			 */
609 			error = EINVAL;
610 			goto error_exit;
611 		}
612 
613 		/*
614 		 * Check a few values (could do some more):
615 		 * - logical sector size: power of 2, >= block size
616 		 * - sectors per cluster: power of 2, >= 1
617 		 * - number of sectors:   >= 1, <= size of partition
618 		 */
619 		if ( (SecPerClust == 0)
620 		  || (SecPerClust & (SecPerClust - 1))
621 		  || (pmp->pm_BytesPerSec < bsize)
622 		  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
623 		  || (pmp->pm_HugeSectors == 0)
624 		  || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize)
625 		      > psize)) {
626 			DPRINTF(("consistency checks for GEMDOS\n"));
627 			error = EINVAL;
628 			goto error_exit;
629 		}
630 		/*
631 		 * XXX - Many parts of the msdosfs driver seem to assume that
632 		 * the number of bytes per logical sector (BytesPerSec) will
633 		 * always be the same as the number of bytes per disk block
634 		 * Let's pretend it is.
635 		 */
636 		tmp = pmp->pm_BytesPerSec / bsize;
637 		pmp->pm_BytesPerSec  = bsize;
638 		pmp->pm_HugeSectors *= tmp;
639 		pmp->pm_HiddenSects *= tmp;
640 		pmp->pm_ResSectors  *= tmp;
641 		pmp->pm_Sectors     *= tmp;
642 		pmp->pm_FATsecs     *= tmp;
643 		SecPerClust         *= tmp;
644 	}
645 
646 	/* Check that fs has nonzero FAT size */
647 	if (pmp->pm_FATsecs == 0) {
648 		DPRINTF(("FATsecs is 0\n"));
649 		error = EINVAL;
650 		goto error_exit;
651 	}
652 
653 	pmp->pm_fatblk = pmp->pm_ResSectors;
654 	if (FAT32(pmp)) {
655 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
656 		pmp->pm_firstcluster = pmp->pm_fatblk
657 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
658 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
659 	} else {
660 		pmp->pm_rootdirblk = pmp->pm_fatblk +
661 			(pmp->pm_FATs * pmp->pm_FATsecs);
662 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
663 				       + pmp->pm_BytesPerSec - 1)
664 			/ pmp->pm_BytesPerSec;/* in sectors */
665 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
666 	}
667 
668 	pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
669 	    SecPerClust;
670 	pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
671 	pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
672 
673 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
674 		if (pmp->pm_nmbrofclusters <= (0xff0 - 2)) {
675 			pmp->pm_fatmask = FAT12_MASK;
676 			pmp->pm_fatmult = 3;
677 			pmp->pm_fatdiv = 2;
678 		} else {
679 			pmp->pm_fatmask = FAT16_MASK;
680 			pmp->pm_fatmult = 2;
681 			pmp->pm_fatdiv = 1;
682 		}
683 	} else if (pmp->pm_fatmask == 0) {
684 		if (pmp->pm_maxcluster
685 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
686 			/*
687 			 * This will usually be a floppy disk. This size makes
688 			 * sure that one FAT entry will not be split across
689 			 * multiple blocks.
690 			 */
691 			pmp->pm_fatmask = FAT12_MASK;
692 			pmp->pm_fatmult = 3;
693 			pmp->pm_fatdiv = 2;
694 		} else {
695 			pmp->pm_fatmask = FAT16_MASK;
696 			pmp->pm_fatmult = 2;
697 			pmp->pm_fatdiv = 1;
698 		}
699 	}
700 	if (FAT12(pmp))
701 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
702 	else
703 		pmp->pm_fatblocksize = MAXBSIZE;
704 
705 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
706 	pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
707 
708 	/*
709 	 * Compute mask and shift value for isolating cluster relative byte
710 	 * offsets and cluster numbers from a file offset.
711 	 */
712 	pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
713 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
714 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
715 
716 	/*
717 	 * Check for valid cluster size
718 	 * must be a power of 2
719 	 */
720 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
721 		DPRINTF(("bpcluster %lu cnshift %lu\n",
722 		    pmp->pm_bpcluster, pmp->pm_cnshift));
723 		error = EINVAL;
724 		goto error_exit;
725 	}
726 
727 	/*
728 	 * Cluster size must be within limit of MAXBSIZE.
729 	 * Many FAT filesystems will not have clusters larger than
730 	 * 32KiB due to limits in Windows versions before Vista.
731 	 */
732 	if (pmp->pm_bpcluster > MAXBSIZE) {
733 		DPRINTF(("bpcluster %lu > MAXBSIZE %d\n",
734 		    pmp->pm_bpcluster, MAXBSIZE));
735 		error = EINVAL;
736 		goto error_exit;
737 	}
738 
739 	/*
740 	 * Release the bootsector buffer.
741 	 */
742 	brelse(bp, BC_AGE);
743 	bp = NULL;
744 
745 	/*
746 	 * Check FSInfo.
747 	 */
748 	if (pmp->pm_fsinfo) {
749 		struct fsinfo *fp;
750 
751 		/*
752 		 * XXX	If the fsinfo block is stored on media with
753 		 *	2KB or larger sectors, is the fsinfo structure
754 		 *	padded at the end or in the middle?
755 		 */
756 		if ((error = bread(devvp, de_bn2kb(pmp, pmp->pm_fsinfo),
757 		    pmp->pm_BytesPerSec, NOCRED, 0, &bp)) != 0)
758 			goto error_exit;
759 		fp = (struct fsinfo *)bp->b_data;
760 		if (!memcmp(fp->fsisig1, "RRaA", 4)
761 		    && !memcmp(fp->fsisig2, "rrAa", 4)
762 		    && !memcmp(fp->fsisig3, "\0\0\125\252", 4)
763 		    && !memcmp(fp->fsisig4, "\0\0\125\252", 4))
764 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
765 		else
766 			pmp->pm_fsinfo = 0;
767 		brelse(bp, 0);
768 		bp = NULL;
769 	}
770 
771 	/*
772 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
773 	 * XXX
774 	 */
775 	if (pmp->pm_fsinfo) {
776 		if ((pmp->pm_nxtfree == 0xffffffffUL) ||
777 		    (pmp->pm_nxtfree > pmp->pm_maxcluster))
778 			pmp->pm_fsinfo = 0;
779 	}
780 
781 	/*
782 	 * Allocate memory for the bitmap of allocated clusters, and then
783 	 * fill it in.
784 	 */
785 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS)
786 				   / N_INUSEBITS)
787 				  * sizeof(*pmp->pm_inusemap),
788 				  M_MSDOSFSFAT, M_WAITOK);
789 
790 	/*
791 	 * fillinusemap() needs pm_devvp.
792 	 */
793 	pmp->pm_dev = dev;
794 	pmp->pm_devvp = devvp;
795 
796 	/*
797 	 * Have the inuse map filled in.
798 	 */
799 	if ((error = fillinusemap(pmp)) != 0) {
800 		DPRINTF(("fillinusemap %d\n", error));
801 		goto error_exit;
802 	}
803 
804 	/*
805 	 * If they want FAT updates to be synchronous then let them suffer
806 	 * the performance degradation in exchange for the on disk copy of
807 	 * the FAT being correct just about all the time.  I suppose this
808 	 * would be a good thing to turn on if the kernel is still flakey.
809 	 */
810 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
811 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
812 
813 	/*
814 	 * Finish up.
815 	 */
816 	if (ronly)
817 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
818 	else
819 		pmp->pm_fmod = 1;
820 	mp->mnt_data = pmp;
821 	mp->mnt_stat.f_fsidx.__fsid_val[0] = (long)dev;
822 	mp->mnt_stat.f_fsidx.__fsid_val[1] = makefstype(MOUNT_MSDOS);
823 	mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
824 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
825 	mp->mnt_flag |= MNT_LOCAL;
826 	mp->mnt_dev_bshift = pmp->pm_bnshift;
827 	mp->mnt_fs_bshift = pmp->pm_cnshift;
828 
829 	/*
830 	 * If we ever do quotas for DOS filesystems this would be a place
831 	 * to fill in the info in the msdosfsmount structure. You dolt,
832 	 * quotas on dos filesystems make no sense because files have no
833 	 * owners on dos filesystems. of course there is some empty space
834 	 * in the directory entry where we could put uid's and gid's.
835 	 */
836 
837 	spec_node_setmountedfs(devvp, mp);
838 
839 	return (0);
840 
841 error_exit:
842 	fstrans_unmount(mp);
843 	if (bp)
844 		brelse(bp, BC_AGE);
845 	if (pmp) {
846 		if (pmp->pm_inusemap)
847 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
848 		free(pmp, M_MSDOSFSMNT);
849 		mp->mnt_data = NULL;
850 	}
851 	return (error);
852 }
853 
854 int
855 msdosfs_start(struct mount *mp, int flags)
856 {
857 
858 	return (0);
859 }
860 
861 /*
862  * Unmount the filesystem described by mp.
863  */
864 int
865 msdosfs_unmount(struct mount *mp, int mntflags)
866 {
867 	struct msdosfsmount *pmp;
868 	int error, flags;
869 
870 	flags = 0;
871 	if (mntflags & MNT_FORCE)
872 		flags |= FORCECLOSE;
873 	if ((error = vflush(mp, NULLVP, flags)) != 0)
874 		return (error);
875 	pmp = VFSTOMSDOSFS(mp);
876 	if (pmp->pm_devvp->v_type != VBAD)
877 		spec_node_setmountedfs(pmp->pm_devvp, NULL);
878 #ifdef MSDOSFS_DEBUG
879 	{
880 		struct vnode *vp = pmp->pm_devvp;
881 
882 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
883 		printf("flag %08x, usecount %d, writecount %d, holdcnt %d\n",
884 		    vp->v_vflag | vp->v_iflag | vp->v_uflag, vp->v_usecount,
885 		    vp->v_writecount, vp->v_holdcnt);
886 		printf("mount %p, op %p\n",
887 		    vp->v_mount, vp->v_op);
888 		printf("freef %p, freeb %p, mount %p\n",
889 		    vp->v_freelist.tqe_next, vp->v_freelist.tqe_prev,
890 		    vp->v_mount);
891 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %d, type %d\n",
892 		    vp->v_cleanblkhd.lh_first,
893 		    vp->v_dirtyblkhd.lh_first,
894 		    vp->v_numoutput, vp->v_type);
895 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
896 		    vp->v_socket, vp->v_tag,
897 		    ((u_int *)vp->v_data)[0],
898 		    ((u_int *)vp->v_data)[1]);
899 	}
900 #endif
901 	vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
902 	(void) VOP_CLOSE(pmp->pm_devvp,
903 	    pmp->pm_flags & MSDOSFSMNT_RONLY ? FREAD : FREAD|FWRITE, NOCRED);
904 	vput(pmp->pm_devvp);
905 	msdosfs_fh_destroy(pmp);
906 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
907 	free(pmp, M_MSDOSFSMNT);
908 	mp->mnt_data = NULL;
909 	mp->mnt_flag &= ~MNT_LOCAL;
910 	fstrans_unmount(mp);
911 	return (0);
912 }
913 
914 int
915 msdosfs_root(struct mount *mp, struct vnode **vpp)
916 {
917 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
918 	struct denode *ndep;
919 	int error;
920 
921 #ifdef MSDOSFS_DEBUG
922 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
923 #endif
924 	if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0)
925 		return (error);
926 	*vpp = DETOV(ndep);
927 	return (0);
928 }
929 
930 int
931 msdosfs_statvfs(struct mount *mp, struct statvfs *sbp)
932 {
933 	struct msdosfsmount *pmp;
934 
935 	pmp = VFSTOMSDOSFS(mp);
936 	sbp->f_bsize = pmp->pm_bpcluster;
937 	sbp->f_frsize = sbp->f_bsize;
938 	sbp->f_iosize = pmp->pm_bpcluster;
939 	sbp->f_blocks = pmp->pm_nmbrofclusters;
940 	sbp->f_bfree = pmp->pm_freeclustercount;
941 	sbp->f_bavail = pmp->pm_freeclustercount;
942 	sbp->f_bresvd = 0;
943 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
944 	sbp->f_ffree = 0;	/* what to put in here? */
945 	sbp->f_favail = 0;	/* what to put in here? */
946 	sbp->f_fresvd = 0;
947 	copy_statvfs_info(sbp, mp);
948 	return (0);
949 }
950 
951 int
952 msdosfs_sync(struct mount *mp, int waitfor, kauth_cred_t cred)
953 {
954 	struct vnode *vp, *mvp;
955 	struct denode *dep;
956 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
957 	int error, allerror = 0;
958 
959 	/*
960 	 * If we ever switch to not updating all of the FATs all the time,
961 	 * this would be the place to update them from the first one.
962 	 */
963 	if (pmp->pm_fmod != 0) {
964 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
965 			panic("msdosfs_sync: rofs mod");
966 		else {
967 			/* update FATs here */
968 		}
969 	}
970 	/* Allocate a marker vnode. */
971 	mvp = vnalloc(mp);
972 	fstrans_start(mp, FSTRANS_SHARED);
973 	/*
974 	 * Write back each (modified) denode.
975 	 */
976 	mutex_enter(&mntvnode_lock);
977 loop:
978 	for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp; vp = vunmark(mvp)) {
979 		vmark(mvp, vp);
980 		if (vp->v_mount != mp || vismarker(vp))
981 			continue;
982 		mutex_enter(vp->v_interlock);
983 		dep = VTODE(vp);
984 		if (waitfor == MNT_LAZY || vp->v_type == VNON ||
985 		    dep == NULL || (((dep->de_flag &
986 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0) &&
987 		     (LIST_EMPTY(&vp->v_dirtyblkhd) &&
988 		      UVM_OBJ_IS_CLEAN(&vp->v_uobj)))) {
989 			mutex_exit(vp->v_interlock);
990 			continue;
991 		}
992 		mutex_exit(&mntvnode_lock);
993 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT);
994 		if (error) {
995 			mutex_enter(&mntvnode_lock);
996 			if (error == ENOENT) {
997 				(void)vunmark(mvp);
998 				goto loop;
999 			}
1000 			continue;
1001 		}
1002 		if ((error = VOP_FSYNC(vp, cred,
1003 		    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0)) != 0)
1004 			allerror = error;
1005 		vput(vp);
1006 		mutex_enter(&mntvnode_lock);
1007 	}
1008 	mutex_exit(&mntvnode_lock);
1009 	vnfree(mvp);
1010 
1011 	/*
1012 	 * Force stale file system control information to be flushed.
1013 	 */
1014 	if ((error = VOP_FSYNC(pmp->pm_devvp, cred,
1015 	    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0)) != 0)
1016 		allerror = error;
1017 	fstrans_done(mp);
1018 	return (allerror);
1019 }
1020 
1021 int
1022 msdosfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
1023 {
1024 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
1025 	struct defid defh;
1026 	struct denode *dep;
1027 	uint32_t gen;
1028 	int error;
1029 
1030 	if (fhp->fid_len != sizeof(struct defid)) {
1031 		DPRINTF(("fid_len %d %zd\n", fhp->fid_len,
1032 		    sizeof(struct defid)));
1033 		return EINVAL;
1034 	}
1035 	memcpy(&defh, fhp, sizeof(defh));
1036 	error = msdosfs_fh_lookup(pmp, defh.defid_dirclust, defh.defid_dirofs,
1037 	    &gen);
1038 	if (error == 0 && gen != defh.defid_gen)
1039 		error = ESTALE;
1040 	if (error) {
1041 		*vpp = NULLVP;
1042 		return error;
1043 	}
1044 	error = deget(pmp, defh.defid_dirclust, defh.defid_dirofs, &dep);
1045 	if (error) {
1046 		DPRINTF(("deget %d\n", error));
1047 		*vpp = NULLVP;
1048 		return (error);
1049 	}
1050 	*vpp = DETOV(dep);
1051 	return (0);
1052 }
1053 
1054 int
1055 msdosfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size)
1056 {
1057 	struct msdosfsmount *pmp = VFSTOMSDOSFS(vp->v_mount);
1058 	struct denode *dep;
1059 	struct defid defh;
1060 	int error;
1061 
1062 	if (*fh_size < sizeof(struct defid)) {
1063 		*fh_size = sizeof(struct defid);
1064 		return E2BIG;
1065 	}
1066 	*fh_size = sizeof(struct defid);
1067 	dep = VTODE(vp);
1068 	memset(&defh, 0, sizeof(defh));
1069 	defh.defid_len = sizeof(struct defid);
1070 	defh.defid_dirclust = dep->de_dirclust;
1071 	defh.defid_dirofs = dep->de_diroffset;
1072 	error = msdosfs_fh_enter(pmp, dep->de_dirclust, dep->de_diroffset,
1073 	     &defh.defid_gen);
1074 	if (error == 0)
1075 		memcpy(fhp, &defh, sizeof(defh));
1076 	return error;
1077 }
1078 
1079 int
1080 msdosfs_vget(struct mount *mp, ino_t ino,
1081     struct vnode **vpp)
1082 {
1083 
1084 	return (EOPNOTSUPP);
1085 }
1086 
1087 int
1088 msdosfs_suspendctl(struct mount *mp, int cmd)
1089 {
1090 	int error;
1091 	struct lwp *l = curlwp;
1092 
1093 	switch (cmd) {
1094 	case SUSPEND_SUSPEND:
1095 		if ((error = fstrans_setstate(mp, FSTRANS_SUSPENDING)) != 0)
1096 			return error;
1097 		error = msdosfs_sync(mp, MNT_WAIT, l->l_proc->p_cred);
1098 		if (error == 0)
1099 			error = fstrans_setstate(mp, FSTRANS_SUSPENDED);
1100 		if (error != 0) {
1101 			(void) fstrans_setstate(mp, FSTRANS_NORMAL);
1102 			return error;
1103 		}
1104 		return 0;
1105 
1106 	case SUSPEND_RESUME:
1107 		return fstrans_setstate(mp, FSTRANS_NORMAL);
1108 
1109 	default:
1110 		return EINVAL;
1111 	}
1112 }
1113