xref: /freebsd/sys/fs/msdosfs/msdosfs_vfsops.c (revision f856af0466c076beef4ea9b15d088e1119a945b8)
1 /* $FreeBSD$ */
2 /*	$NetBSD: msdosfs_vfsops.c,v 1.51 1997/11/17 15:36:58 ws Exp $	*/
3 
4 /*-
5  * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
6  * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
7  * All rights reserved.
8  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by TooLs GmbH.
21  * 4. The name of TooLs GmbH may not be used to endorse or promote products
22  *    derived from this software without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
30  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
31  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
32  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
33  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 /*-
36  * Written by Paul Popelka (paulp@uts.amdahl.com)
37  *
38  * You can do anything you want with this software, just don't say you wrote
39  * it, and don't remove this notice.
40  *
41  * This software is provided "as is".
42  *
43  * The author supplies this software to be publicly redistributed on the
44  * understanding that the author is not responsible for the correct
45  * functioning of this software in any circumstances and is not liable for
46  * any damages caused by this software.
47  *
48  * October 1992
49  */
50 
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/conf.h>
54 #include <sys/namei.h>
55 #include <sys/priv.h>
56 #include <sys/proc.h>
57 #include <sys/kernel.h>
58 #include <sys/vnode.h>
59 #include <sys/mount.h>
60 #include <sys/bio.h>
61 #include <sys/buf.h>
62 #include <sys/fcntl.h>
63 #include <sys/malloc.h>
64 #include <sys/stat.h> 				/* defines ALLPERMS */
65 #include <sys/iconv.h>
66 #include <sys/mutex.h>
67 
68 #include <fs/msdosfs/bpb.h>
69 #include <fs/msdosfs/bootsect.h>
70 #include <fs/msdosfs/msdosfsmount.h>
71 #include <fs/msdosfs/direntry.h>
72 #include <fs/msdosfs/denode.h>
73 #include <fs/msdosfs/fat.h>
74 
75 #include <geom/geom.h>
76 #include <geom/geom_vfs.h>
77 
78 #include "opt_msdosfs.h"
79 
80 /* List of mount options we support */
81 static const char *msdosfs_opts[] = {
82 	"from",
83 	"export", "force", "sync",
84 	"uid", "gid", "mask", "dirmask",
85 	"shortname", "shortnames", "longname", "longnames", "nowin95", "win95",
86 	"kiconv", "cs_win", "cs_dos", "cs_local",
87 	NULL
88 };
89 
90 #define MSDOSFS_DFLTBSIZE       4096
91 
92 #if 1 /*def PC98*/
93 /*
94  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
95  *       garbage or a random value :-{
96  *       If you want to use that broken-signatured media, define the
97  *       following symbol even though PC/AT.
98  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
99  */
100 #define	MSDOSFS_NOCHECKSIG
101 #endif
102 
103 MALLOC_DEFINE(M_MSDOSFSMNT, "msdosfs_mount", "MSDOSFS mount structure");
104 static MALLOC_DEFINE(M_MSDOSFSFAT, "msdosfs_fat", "MSDOSFS file allocation table");
105 
106 struct iconv_functions *msdosfs_iconv = NULL;
107 
108 static int	update_mp(struct mount *mp, struct thread *td);
109 static int	mountmsdosfs(struct vnode *devvp, struct mount *mp,
110 		    struct thread *td);
111 static vfs_fhtovp_t	msdosfs_fhtovp;
112 static vfs_mount_t	msdosfs_mount;
113 static vfs_root_t	msdosfs_root;
114 static vfs_statfs_t	msdosfs_statfs;
115 static vfs_sync_t	msdosfs_sync;
116 static vfs_unmount_t	msdosfs_unmount;
117 static vfs_vptofh_t	msdosfs_vptofh;
118 
119 /* Maximum length of a character set name (arbitrary). */
120 #define	MAXCSLEN	64
121 
122 static int
123 update_mp(mp, td)
124 	struct mount *mp;
125 	struct thread *td;
126 {
127 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
128 	void *dos, *win, *local;
129 	int error, v;
130 
131 	if (!vfs_getopt(mp->mnt_optnew, "kiconv", NULL, NULL)) {
132 		if (msdosfs_iconv != NULL) {
133 			error = vfs_getopt(mp->mnt_optnew,
134 			    "cs_win", &win, NULL);
135 			if (!error)
136 				error = vfs_getopt(mp->mnt_optnew,
137 				    "cs_local", &local, NULL);
138 			if (!error)
139 				error = vfs_getopt(mp->mnt_optnew,
140 				    "cs_dos", &dos, NULL);
141 			if (!error) {
142 				msdosfs_iconv->open(win, local, &pmp->pm_u2w);
143 				msdosfs_iconv->open(local, win, &pmp->pm_w2u);
144 				msdosfs_iconv->open(dos, local, &pmp->pm_u2d);
145 				msdosfs_iconv->open(local, dos, &pmp->pm_d2u);
146 			}
147 			if (error != 0)
148 				return (error);
149 		} else {
150 			pmp->pm_w2u = NULL;
151 			pmp->pm_u2w = NULL;
152 			pmp->pm_d2u = NULL;
153 			pmp->pm_u2d = NULL;
154 		}
155 	}
156 
157 	if (1 == vfs_scanopt(mp->mnt_optnew, "gid", "%d", &v))
158 		pmp->pm_gid = v;
159 	if (1 == vfs_scanopt(mp->mnt_optnew, "uid", "%d", &v))
160 		pmp->pm_uid = v;
161 	if (1 == vfs_scanopt(mp->mnt_optnew, "mask", "%d", &v))
162 		pmp->pm_mask = v & ALLPERMS;
163 	if (1 == vfs_scanopt(mp->mnt_optnew, "dirmask", "%d", &v))
164 		pmp->pm_dirmask = v & ALLPERMS;
165 	vfs_flagopt(mp->mnt_optnew, "shortname",
166 	    &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
167 	vfs_flagopt(mp->mnt_optnew, "shortnames",
168 	    &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
169 	vfs_flagopt(mp->mnt_optnew, "longname",
170 	    &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
171 	vfs_flagopt(mp->mnt_optnew, "longnames",
172 	    &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
173 	vfs_flagopt(mp->mnt_optnew, "kiconv",
174 	    &pmp->pm_flags, MSDOSFSMNT_KICONV);
175 
176 	if (vfs_getopt(mp->mnt_optnew, "nowin95", NULL, NULL) == 0)
177 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
178 	else
179 		pmp->pm_flags &= ~MSDOSFSMNT_NOWIN95;
180 
181 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
182 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
183 	else if (!(pmp->pm_flags &
184 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
185 		struct vnode *rootvp;
186 
187 		/*
188 		 * Try to divine whether to support Win'95 long filenames
189 		 */
190 		if (FAT32(pmp))
191 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
192 		else {
193 			if ((error =
194 			    msdosfs_root(mp, LK_EXCLUSIVE, &rootvp, td)) != 0)
195 				return error;
196 			pmp->pm_flags |= findwin95(VTODE(rootvp))
197 				? MSDOSFSMNT_LONGNAME
198 					: MSDOSFSMNT_SHORTNAME;
199 			vput(rootvp);
200 		}
201 	}
202 	return 0;
203 }
204 
205 static int
206 msdosfs_cmount(struct mntarg *ma, void *data, int flags, struct thread *td)
207 {
208 	struct msdosfs_args args;
209 	int error;
210 
211 	if (data == NULL)
212 		return (EINVAL);
213 	error = copyin(data, &args, sizeof args);
214 	if (error)
215 		return (error);
216 
217 	ma = mount_argsu(ma, "from", args.fspec, MAXPATHLEN);
218 	ma = mount_arg(ma, "export", &args.export, sizeof args.export);
219 	ma = mount_argf(ma, "uid", "%d", args.uid);
220 	ma = mount_argf(ma, "gid", "%d", args.gid);
221 	ma = mount_argf(ma, "mask", "%d", args.mask);
222 	ma = mount_argf(ma, "dirmask", "%d", args.dirmask);
223 
224         ma = mount_argb(ma, args.flags & MSDOSFSMNT_SHORTNAME, "noshortname");
225         ma = mount_argb(ma, args.flags & MSDOSFSMNT_LONGNAME, "nolongname");
226         ma = mount_argb(ma, !(args.flags & MSDOSFSMNT_NOWIN95), "nowin95");
227         ma = mount_argb(ma, args.flags & MSDOSFSMNT_KICONV, "nokiconv");
228 
229         ma = mount_argsu(ma, "cs_win", args.cs_win, MAXCSLEN);
230         ma = mount_argsu(ma, "cs_dos", args.cs_dos, MAXCSLEN);
231         ma = mount_argsu(ma, "cs_local", args.cs_local, MAXCSLEN);
232 
233 	error = kernel_mount(ma, flags);
234 
235 	return (error);
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 static int
244 msdosfs_mount(struct mount *mp, struct thread *td)
245 {
246 	struct vnode *devvp;	  /* vnode for blk device to mount */
247 	/* msdosfs specific mount control block */
248 	struct msdosfsmount *pmp = NULL;
249 	struct nameidata ndp;
250 	int error, flags;
251 	mode_t accessmode;
252 	char *from;
253 
254 	if (vfs_filteropt(mp->mnt_optnew, msdosfs_opts))
255 		return (EINVAL);
256 
257 	/*
258 	 * If updating, check whether changing from read-only to
259 	 * read/write; if there is no device name, that's all we do.
260 	 */
261 	if (mp->mnt_flag & MNT_UPDATE) {
262 		pmp = VFSTOMSDOSFS(mp);
263 
264 		if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0)) {
265 			/*
266 			 * Forbid export requests if filesystem has
267 			 * MSDOSFS_LARGEFS flag set.
268 			 */
269 			if ((pmp->pm_flags & MSDOSFS_LARGEFS) != 0) {
270 				vfs_mount_error(mp,
271 				    "MSDOSFS_LARGEFS flag set, cannot export");
272 				return (EOPNOTSUPP);
273 			}
274 		}
275 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) &&
276 		    vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
277 			error = VFS_SYNC(mp, MNT_WAIT, td);
278 			if (error)
279 				return (error);
280 			flags = WRITECLOSE;
281 			if (mp->mnt_flag & MNT_FORCE)
282 				flags |= FORCECLOSE;
283 			error = vflush(mp, 0, flags, td);
284 			if (error)
285 				return (error);
286 			DROP_GIANT();
287 			g_topology_lock();
288 			g_access(pmp->pm_cp, 0, -1, 0);
289 			g_topology_unlock();
290 			PICKUP_GIANT();
291 			/* Now the volume is clean. Mark it. */
292 			error = markvoldirty(pmp, 0);
293 			if (error && (flags & FORCECLOSE) == 0)
294 				return (error);
295 		} else if ((pmp->pm_flags & MSDOSFSMNT_RONLY) &&
296 		    !vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
297 			/*
298 			 * If upgrade to read-write by non-root, then verify
299 			 * that user has necessary permissions on the device.
300 			 */
301 			devvp = pmp->pm_devvp;
302 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
303 			error = VOP_ACCESS(devvp, VREAD | VWRITE,
304 			   td->td_ucred, td);
305 			if (error)
306 				error = priv_check(td, PRIV_VFS_MOUNT_PERM);
307 			if (error) {
308 				VOP_UNLOCK(devvp, 0, td);
309 				return (error);
310 			}
311 			VOP_UNLOCK(devvp, 0, td);
312 			DROP_GIANT();
313 			g_topology_lock();
314 			error = g_access(pmp->pm_cp, 0, 1, 0);
315 			g_topology_unlock();
316 			PICKUP_GIANT();
317 			if (error)
318 				return (error);
319 
320 			/* Now that the volume is modifiable, mark it dirty. */
321 			error = markvoldirty(pmp, 1);
322 			if (error)
323 				return (error);
324 		}
325 		vfs_flagopt(mp->mnt_optnew, "ro",
326 		    &pmp->pm_flags, MSDOSFSMNT_RONLY);
327 		vfs_flagopt(mp->mnt_optnew, "ro",
328 		    &mp->mnt_flag, MNT_RDONLY);
329 		if (vfs_getopt(mp->mnt_optnew, "from", NULL, NULL)) {
330 #ifdef	__notyet__	/* doesn't work correctly with current mountd	XXX */
331 			if (args.flags & MSDOSFSMNT_MNTOPT) {
332 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
333 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
334 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
335 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
336 			}
337 #endif
338 		}
339 	}
340 	/*
341 	 * Not an update, or updating the name: look up the name
342 	 * and verify that it refers to a sensible disk device.
343 	 */
344 	if (vfs_getopt(mp->mnt_optnew, "from", (void **)&from, NULL))
345 		return (EINVAL);
346 	NDINIT(&ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, from, td);
347 	error = namei(&ndp);
348 	if (error)
349 		return (error);
350 	devvp = ndp.ni_vp;
351 	NDFREE(&ndp, NDF_ONLY_PNBUF);
352 
353 	if (!vn_isdisk(devvp, &error)) {
354 		vput(devvp);
355 		return (error);
356 	}
357 	/*
358 	 * If mount by non-root, then verify that user has necessary
359 	 * permissions on the device.
360 	 */
361 	accessmode = VREAD;
362 	if ((mp->mnt_flag & MNT_RDONLY) == 0)
363 		accessmode |= VWRITE;
364 	error = VOP_ACCESS(devvp, accessmode, td->td_ucred, td);
365 	if (error)
366 		error = priv_check(td, PRIV_VFS_MOUNT_PERM);
367 	if (error) {
368 		vput(devvp);
369 		return (error);
370 	}
371 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
372 		error = mountmsdosfs(devvp, mp, td);
373 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
374 		pmp = VFSTOMSDOSFS(mp);
375 #endif
376 	} else {
377 		if (devvp != pmp->pm_devvp)
378 			error = EINVAL;	/* XXX needs translation */
379 		else
380 			vput(devvp);
381 	}
382 	if (error) {
383 		vrele(devvp);
384 		return (error);
385 	}
386 
387 	error = update_mp(mp, td);
388 	if (error) {
389 		if ((mp->mnt_flag & MNT_UPDATE) == 0)
390 			msdosfs_unmount(mp, MNT_FORCE, td);
391 		return error;
392 	}
393 
394 	vfs_mountedfrom(mp, from);
395 #ifdef MSDOSFS_DEBUG
396 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
397 #endif
398 	return (0);
399 }
400 
401 static int
402 mountmsdosfs(devvp, mp, td)
403 	struct vnode *devvp;
404 	struct mount *mp;
405 	struct thread *td;
406 {
407 	struct msdosfsmount *pmp;
408 	struct buf *bp;
409 	struct cdev *dev = devvp->v_rdev;
410 	union bootsector *bsp;
411 	struct byte_bpb33 *b33;
412 	struct byte_bpb50 *b50;
413 	struct byte_bpb710 *b710;
414 	u_int8_t SecPerClust;
415 	u_long clusters;
416 	int	ronly, error;
417 	struct g_consumer *cp;
418 	struct bufobj *bo;
419 
420 	ronly = !vfs_getopt(mp->mnt_optnew, "ro", NULL, NULL);
421 	/* XXX: use VOP_ACCESS to check FS perms */
422 	DROP_GIANT();
423 	g_topology_lock();
424 	error = g_vfs_open(devvp, &cp, "msdos", ronly ? 0 : 1);
425 	g_topology_unlock();
426 	PICKUP_GIANT();
427 	VOP_UNLOCK(devvp, 0, td);
428 	if (error)
429 		return (error);
430 
431 	bo = &devvp->v_bufobj;
432 	bp  = NULL; /* both used in error_exit */
433 	pmp = NULL;
434 
435 	/*
436 	 * Read the boot sector of the filesystem, and then check the
437 	 * boot signature.  If not a dos boot sector then error out.
438 	 *
439 	 * NOTE: 2048 is a maximum sector size in current...
440 	 */
441 	error = bread(devvp, 0, 2048, NOCRED, &bp);
442 	if (error)
443 		goto error_exit;
444 	bp->b_flags |= B_AGE;
445 	bsp = (union bootsector *)bp->b_data;
446 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
447 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
448 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
449 
450 #ifndef MSDOSFS_NOCHECKSIG
451 	if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
452 	    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
453 		error = EINVAL;
454 		goto error_exit;
455 	}
456 #endif
457 
458 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
459 	pmp->pm_mountp = mp;
460 	pmp->pm_cp = cp;
461 	pmp->pm_bo = bo;
462 
463 	/*
464 	 * Compute several useful quantities from the bpb in the
465 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
466 	 * the fields that are different between dos 5 and dos 3.3.
467 	 */
468 	SecPerClust = b50->bpbSecPerClust;
469 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
470 	if (pmp->pm_BytesPerSec < DEV_BSIZE) {
471 		error = EINVAL;
472 		goto error_exit;
473 	}
474 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
475 	pmp->pm_FATs = b50->bpbFATs;
476 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
477 	pmp->pm_Sectors = getushort(b50->bpbSectors);
478 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
479 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
480 	pmp->pm_Heads = getushort(b50->bpbHeads);
481 	pmp->pm_Media = b50->bpbMedia;
482 
483 	/* calculate the ratio of sector size to DEV_BSIZE */
484 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
485 
486 	/* XXX - We should probably check more values here */
487 	if (!pmp->pm_BytesPerSec || !SecPerClust
488 		|| !pmp->pm_Heads
489 #ifdef PC98
490     		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) {
491 #else
492 		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
493 #endif
494 		error = EINVAL;
495 		goto error_exit;
496 	}
497 
498 	if (pmp->pm_Sectors == 0) {
499 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
500 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
501 	} else {
502 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
503 		pmp->pm_HugeSectors = pmp->pm_Sectors;
504 	}
505 #ifndef MSDOSFS_LARGE
506 	if (pmp->pm_HugeSectors > 0xffffffff /
507 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
508 		/*
509 		 * We cannot deal currently with this size of disk
510 		 * due to fileid limitations (see msdosfs_getattr and
511 		 * msdosfs_readdir)
512 		 */
513 		error = EINVAL;
514 		printf("mountmsdosfs(): disk too big, sorry\n");
515 		goto error_exit;
516 	}
517 #endif	/* !MSDOSFS_LARGE */
518 
519 	if (pmp->pm_RootDirEnts == 0) {
520 		if (pmp->pm_Sectors
521 		    || pmp->pm_FATsecs
522 		    || getushort(b710->bpbFSVers)) {
523 			error = EINVAL;
524 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
525 			goto error_exit;
526 		}
527 		pmp->pm_fatmask = FAT32_MASK;
528 		pmp->pm_fatmult = 4;
529 		pmp->pm_fatdiv = 1;
530 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
531 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
532 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
533 		else
534 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
535 	} else
536 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
537 
538 	/*
539 	 * Check a few values (could do some more):
540 	 * - logical sector size: power of 2, >= block size
541 	 * - sectors per cluster: power of 2, >= 1
542 	 * - number of sectors:   >= 1, <= size of partition
543 	 * - number of FAT sectors: >= 1
544 	 */
545 	if ( (SecPerClust == 0)
546 	  || (SecPerClust & (SecPerClust - 1))
547 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
548 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
549 	  || (pmp->pm_HugeSectors == 0)
550 	  || (pmp->pm_FATsecs == 0)
551 	) {
552 		error = EINVAL;
553 		goto error_exit;
554 	}
555 
556 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
557 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
558 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
559 	SecPerClust         *= pmp->pm_BlkPerSec;
560 
561 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
562 
563 	if (FAT32(pmp)) {
564 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
565 		pmp->pm_firstcluster = pmp->pm_fatblk
566 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
567 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
568 	} else {
569 		pmp->pm_rootdirblk = pmp->pm_fatblk +
570 			(pmp->pm_FATs * pmp->pm_FATsecs);
571 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
572 				       + DEV_BSIZE - 1)
573 			/ DEV_BSIZE; /* in blocks */
574 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
575 	}
576 
577 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
578 	    SecPerClust + 1;
579 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
580 
581 	if (pmp->pm_fatmask == 0) {
582 		if (pmp->pm_maxcluster
583 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
584 			/*
585 			 * This will usually be a floppy disk. This size makes
586 			 * sure that one fat entry will not be split across
587 			 * multiple blocks.
588 			 */
589 			pmp->pm_fatmask = FAT12_MASK;
590 			pmp->pm_fatmult = 3;
591 			pmp->pm_fatdiv = 2;
592 		} else {
593 			pmp->pm_fatmask = FAT16_MASK;
594 			pmp->pm_fatmult = 2;
595 			pmp->pm_fatdiv = 1;
596 		}
597 	}
598 
599 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
600 	if (pmp->pm_maxcluster >= clusters) {
601 		printf("Warning: number of clusters (%ld) exceeds FAT "
602 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
603 		pmp->pm_maxcluster = clusters - 1;
604 	}
605 
606 
607 	if (FAT12(pmp))
608 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
609 	else
610 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
611 
612 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
613 	pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
614 
615 	/*
616 	 * Compute mask and shift value for isolating cluster relative byte
617 	 * offsets and cluster numbers from a file offset.
618 	 */
619 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
620 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
621 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
622 
623 	/*
624 	 * Check for valid cluster size
625 	 * must be a power of 2
626 	 */
627 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
628 		error = EINVAL;
629 		goto error_exit;
630 	}
631 
632 	/*
633 	 * Release the bootsector buffer.
634 	 */
635 	brelse(bp);
636 	bp = NULL;
637 
638 	/*
639 	 * Check FSInfo.
640 	 */
641 	if (pmp->pm_fsinfo) {
642 		struct fsinfo *fp;
643 
644 		if ((error = bread(devvp, pmp->pm_fsinfo, fsi_size(pmp),
645 		    NOCRED, &bp)) != 0)
646 			goto error_exit;
647 		fp = (struct fsinfo *)bp->b_data;
648 		if (!bcmp(fp->fsisig1, "RRaA", 4)
649 		    && !bcmp(fp->fsisig2, "rrAa", 4)
650 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
651 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4)) {
652 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
653 			if (pmp->pm_nxtfree == 0xffffffff)
654 				pmp->pm_nxtfree = CLUST_FIRST;
655 		} else
656 			pmp->pm_fsinfo = 0;
657 		brelse(bp);
658 		bp = NULL;
659 	}
660 
661 	/*
662 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
663 	 */
664 	if (pmp->pm_fsinfo && pmp->pm_nxtfree > pmp->pm_maxcluster) {
665 		printf(
666 		"Next free cluster in FSInfo (%lu) exceeds maxcluster (%lu)\n",
667 		    pmp->pm_nxtfree, pmp->pm_maxcluster);
668 		error = EINVAL;
669 		goto error_exit;
670 	}
671 
672 	/*
673 	 * Allocate memory for the bitmap of allocated clusters, and then
674 	 * fill it in.
675 	 */
676 	pmp->pm_inusemap = malloc(howmany(pmp->pm_maxcluster + 1, N_INUSEBITS)
677 				  * sizeof(*pmp->pm_inusemap),
678 				  M_MSDOSFSFAT, M_WAITOK);
679 
680 	/*
681 	 * fillinusemap() needs pm_devvp.
682 	 */
683 	pmp->pm_devvp = devvp;
684 
685 	/*
686 	 * Have the inuse map filled in.
687 	 */
688 	if ((error = fillinusemap(pmp)) != 0)
689 		goto error_exit;
690 
691 	/*
692 	 * If they want fat updates to be synchronous then let them suffer
693 	 * the performance degradation in exchange for the on disk copy of
694 	 * the fat being correct just about all the time.  I suppose this
695 	 * would be a good thing to turn on if the kernel is still flakey.
696 	 */
697 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
698 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
699 
700 	/*
701 	 * Finish up.
702 	 */
703 	if (ronly)
704 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
705 	else {
706 		/* Mark the volume dirty while it is mounted read/write. */
707 		if ((error = markvoldirty(pmp, 1)) != 0)
708 			goto error_exit;
709 		pmp->pm_fmod = 1;
710 	}
711 	mp->mnt_data = (qaddr_t) pmp;
712 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
713 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
714 	MNT_ILOCK(mp);
715 	mp->mnt_flag |= MNT_LOCAL;
716 	MNT_IUNLOCK(mp);
717 
718 #ifdef MSDOSFS_LARGE
719 	msdosfs_fileno_init(mp);
720 #endif
721 
722 	return 0;
723 
724 error_exit:
725 	if (bp)
726 		brelse(bp);
727 	if (cp != NULL) {
728 		DROP_GIANT();
729 		g_topology_lock();
730 		g_vfs_close(cp, td);
731 		g_topology_unlock();
732 		PICKUP_GIANT();
733 	}
734 	if (pmp) {
735 		if (pmp->pm_inusemap)
736 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
737 		free(pmp, M_MSDOSFSMNT);
738 		mp->mnt_data = (qaddr_t)0;
739 	}
740 	return (error);
741 }
742 
743 /*
744  * Unmount the filesystem described by mp.
745  */
746 static int
747 msdosfs_unmount(mp, mntflags, td)
748 	struct mount *mp;
749 	int mntflags;
750 	struct thread *td;
751 {
752 	struct msdosfsmount *pmp;
753 	int error, flags;
754 
755 	flags = 0;
756 	if (mntflags & MNT_FORCE)
757 		flags |= FORCECLOSE;
758 	error = vflush(mp, 0, flags, td);
759 	if (error)
760 		return error;
761 	pmp = VFSTOMSDOSFS(mp);
762 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
763 		if (pmp->pm_w2u)
764 			msdosfs_iconv->close(pmp->pm_w2u);
765 		if (pmp->pm_u2w)
766 			msdosfs_iconv->close(pmp->pm_u2w);
767 		if (pmp->pm_d2u)
768 			msdosfs_iconv->close(pmp->pm_d2u);
769 		if (pmp->pm_u2d)
770 			msdosfs_iconv->close(pmp->pm_u2d);
771 	}
772 
773 	/* If the volume was mounted read/write, mark it clean now. */
774 	if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) {
775 		error = markvoldirty(pmp, 0);
776 		if (error && (flags & FORCECLOSE) == 0)
777 			return (error);
778 	}
779 #ifdef MSDOSFS_DEBUG
780 	{
781 		struct vnode *vp = pmp->pm_devvp;
782 
783 		VI_LOCK(vp);
784 		vn_printf(vp,
785 		    "msdosfs_umount(): just before calling VOP_CLOSE()\n");
786 		printf("freef %p, freeb %p, mount %p\n",
787 		    TAILQ_NEXT(vp, v_freelist), vp->v_freelist.tqe_prev,
788 		    vp->v_mount);
789 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
790 		    TAILQ_FIRST(&vp->v_bufobj.bo_clean.bv_hd),
791 		    TAILQ_FIRST(&vp->v_bufobj.bo_dirty.bv_hd),
792 		    vp->v_bufobj.bo_numoutput, vp->v_type);
793 		VI_UNLOCK(vp);
794 	}
795 #endif
796 	DROP_GIANT();
797 	g_topology_lock();
798 	g_vfs_close(pmp->pm_cp, td);
799 	g_topology_unlock();
800 	PICKUP_GIANT();
801 	vrele(pmp->pm_devvp);
802 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
803 #ifdef MSDOSFS_LARGE
804 	msdosfs_fileno_free(mp);
805 #endif
806 	free(pmp, M_MSDOSFSMNT);
807 	mp->mnt_data = (qaddr_t)0;
808 	MNT_ILOCK(mp);
809 	mp->mnt_flag &= ~MNT_LOCAL;
810 	MNT_IUNLOCK(mp);
811 	return (error);
812 }
813 
814 static int
815 msdosfs_root(mp, flags, vpp, td)
816 	struct mount *mp;
817 	int flags;
818 	struct vnode **vpp;
819 	struct thread *td;
820 {
821 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
822 	struct denode *ndep;
823 	int error;
824 
825 #ifdef MSDOSFS_DEBUG
826 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
827 #endif
828 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
829 	if (error)
830 		return (error);
831 	*vpp = DETOV(ndep);
832 	return (0);
833 }
834 
835 static int
836 msdosfs_statfs(mp, sbp, td)
837 	struct mount *mp;
838 	struct statfs *sbp;
839 	struct thread *td;
840 {
841 	struct msdosfsmount *pmp;
842 
843 	pmp = VFSTOMSDOSFS(mp);
844 	sbp->f_bsize = pmp->pm_bpcluster;
845 	sbp->f_iosize = pmp->pm_bpcluster;
846 	sbp->f_blocks = pmp->pm_maxcluster + 1;
847 	sbp->f_bfree = pmp->pm_freeclustercount;
848 	sbp->f_bavail = pmp->pm_freeclustercount;
849 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
850 	sbp->f_ffree = 0;	/* what to put in here? */
851 	return (0);
852 }
853 
854 static int
855 msdosfs_sync(mp, waitfor, td)
856 	struct mount *mp;
857 	int waitfor;
858 	struct thread *td;
859 {
860 	struct vnode *vp, *nvp;
861 	struct denode *dep;
862 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
863 	int error, allerror = 0;
864 
865 	/*
866 	 * If we ever switch to not updating all of the fats all the time,
867 	 * this would be the place to update them from the first one.
868 	 */
869 	if (pmp->pm_fmod != 0) {
870 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
871 			panic("msdosfs_sync: rofs mod");
872 		else {
873 			/* update fats here */
874 		}
875 	}
876 	/*
877 	 * Write back each (modified) denode.
878 	 */
879 	MNT_ILOCK(mp);
880 loop:
881 	MNT_VNODE_FOREACH(vp, mp, nvp) {
882 		VI_LOCK(vp);
883 		if (vp->v_type == VNON || (vp->v_iflag & VI_DOOMED)) {
884 			VI_UNLOCK(vp);
885 			continue;
886 		}
887 		MNT_IUNLOCK(mp);
888 		dep = VTODE(vp);
889 		if ((dep->de_flag &
890 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
891 		    (vp->v_bufobj.bo_dirty.bv_cnt == 0 ||
892 		    waitfor == MNT_LAZY)) {
893 			VI_UNLOCK(vp);
894 			MNT_ILOCK(mp);
895 			continue;
896 		}
897 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, td);
898 		if (error) {
899 			MNT_ILOCK(mp);
900 			if (error == ENOENT)
901 				goto loop;
902 			continue;
903 		}
904 		error = VOP_FSYNC(vp, waitfor, td);
905 		if (error)
906 			allerror = error;
907 		VOP_UNLOCK(vp, 0, td);
908 		vrele(vp);
909 		MNT_ILOCK(mp);
910 	}
911 	MNT_IUNLOCK(mp);
912 
913 	/*
914 	 * Flush filesystem control info.
915 	 */
916 	if (waitfor != MNT_LAZY) {
917 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY, td);
918 		error = VOP_FSYNC(pmp->pm_devvp, waitfor, td);
919 		if (error)
920 			allerror = error;
921 		VOP_UNLOCK(pmp->pm_devvp, 0, td);
922 	}
923 	return (allerror);
924 }
925 
926 static int
927 msdosfs_fhtovp(mp, fhp, vpp)
928 	struct mount *mp;
929 	struct fid *fhp;
930 	struct vnode **vpp;
931 {
932 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
933 	struct defid *defhp = (struct defid *) fhp;
934 	struct denode *dep;
935 	int error;
936 
937 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
938 	if (error) {
939 		*vpp = NULLVP;
940 		return (error);
941 	}
942 	*vpp = DETOV(dep);
943 	vnode_create_vobject(*vpp, dep->de_FileSize, curthread);
944 	return (0);
945 }
946 
947 static int
948 msdosfs_vptofh(vp, fhp)
949 	struct vnode *vp;
950 	struct fid *fhp;
951 {
952 	struct denode *dep;
953 	struct defid *defhp;
954 
955 	dep = VTODE(vp);
956 	defhp = (struct defid *)fhp;
957 	defhp->defid_len = sizeof(struct defid);
958 	defhp->defid_dirclust = dep->de_dirclust;
959 	defhp->defid_dirofs = dep->de_diroffset;
960 	/* defhp->defid_gen = dep->de_gen; */
961 	return (0);
962 }
963 
964 static struct vfsops msdosfs_vfsops = {
965 	.vfs_fhtovp =		msdosfs_fhtovp,
966 	.vfs_mount =		msdosfs_mount,
967 	.vfs_cmount =		msdosfs_cmount,
968 	.vfs_root =		msdosfs_root,
969 	.vfs_statfs =		msdosfs_statfs,
970 	.vfs_sync =		msdosfs_sync,
971 	.vfs_unmount =		msdosfs_unmount,
972 	.vfs_vptofh =		msdosfs_vptofh,
973 };
974 
975 VFS_SET(msdosfs_vfsops, msdosfs, 0);
976 MODULE_VERSION(msdosfs, 1);
977