xref: /freebsd/sys/fs/msdosfs/msdosfs_vfsops.c (revision 6af83ee0d2941d18880b6aaa2b4facd1d30c6106)
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/proc.h>
56 #include <sys/kernel.h>
57 #include <sys/vnode.h>
58 #include <sys/mount.h>
59 #include <sys/bio.h>
60 #include <sys/buf.h>
61 #include <sys/fcntl.h>
62 #include <sys/malloc.h>
63 #include <sys/stat.h> 				/* defines ALLPERMS */
64 #include <sys/iconv.h>
65 #include <sys/mutex.h>
66 
67 #include <fs/msdosfs/bpb.h>
68 #include <fs/msdosfs/bootsect.h>
69 #include <fs/msdosfs/msdosfsmount.h>
70 #include <fs/msdosfs/direntry.h>
71 #include <fs/msdosfs/denode.h>
72 #include <fs/msdosfs/fat.h>
73 
74 #include <geom/geom.h>
75 #include <geom/geom_vfs.h>
76 
77 #include "opt_msdosfs.h"
78 
79 /* List of mount options we support */
80 static const char *msdosfs_opts[] = {
81 	"from",
82 	"export",
83 	"uid", "gid", "mask", "dirmask",
84 	"shortname", "longname", "win95",
85 	"kiconv", "cs_win", "cs_dos", "cs_local",
86 	NULL
87 };
88 
89 #define MSDOSFS_DFLTBSIZE       4096
90 
91 #if 1 /*def PC98*/
92 /*
93  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
94  *       garbage or a random value :-{
95  *       If you want to use that broken-signatured media, define the
96  *       following symbol even though PC/AT.
97  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
98  */
99 #define	MSDOSFS_NOCHECKSIG
100 #endif
101 
102 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOSFS mount structure");
103 static MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOSFS file allocation table");
104 
105 struct iconv_functions *msdosfs_iconv = NULL;
106 
107 static int	update_mp(struct mount *mp, struct thread *td);
108 static int	mountmsdosfs(struct vnode *devvp, struct mount *mp,
109 		    struct thread *td);
110 static vfs_fhtovp_t	msdosfs_fhtovp;
111 static vfs_mount_t	msdosfs_mount;
112 static vfs_root_t	msdosfs_root;
113 static vfs_statfs_t	msdosfs_statfs;
114 static vfs_sync_t	msdosfs_sync;
115 static vfs_unmount_t	msdosfs_unmount;
116 static vfs_vptofh_t	msdosfs_vptofh;
117 
118 /* Maximum length of a character set name (arbitrary). */
119 #define	MAXCSLEN	64
120 
121 static int
122 update_mp(mp, td)
123 	struct mount *mp;
124 	struct thread *td;
125 {
126 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
127 	void *dos, *win, *local;
128 	int error, v;
129 
130 	if (!vfs_getopt(mp->mnt_optnew, "kiconv", NULL, NULL)) {
131 		if (msdosfs_iconv != NULL) {
132 			error = vfs_getopt(mp->mnt_optnew,
133 			    "cs_win", &win, NULL);
134 			if (!error)
135 				error = vfs_getopt(mp->mnt_optnew,
136 				    "cs_local", &local, NULL);
137 			if (!error)
138 				error = vfs_getopt(mp->mnt_optnew,
139 				    "cs_dos", &dos, NULL);
140 			if (!error) {
141 				msdosfs_iconv->open(win, local, &pmp->pm_u2w);
142 				msdosfs_iconv->open(local, win, &pmp->pm_w2u);
143 				msdosfs_iconv->open(dos, local, &pmp->pm_u2d);
144 				msdosfs_iconv->open(local, dos, &pmp->pm_d2u);
145 			}
146 			if (error != 0)
147 				return (error);
148 		} else {
149 			pmp->pm_w2u = NULL;
150 			pmp->pm_u2w = NULL;
151 			pmp->pm_d2u = NULL;
152 			pmp->pm_u2d = NULL;
153 		}
154 	}
155 
156 	if (1 == vfs_scanopt(mp->mnt_optnew, "gid", "%d", &v))
157 		pmp->pm_gid = v;
158 	if (1 == vfs_scanopt(mp->mnt_optnew, "uid", "%d", &v))
159 		pmp->pm_uid = v;
160 	if (1 == vfs_scanopt(mp->mnt_optnew, "mask", "%d", &v))
161 		pmp->pm_mask = v & ALLPERMS;
162 	if (1 == vfs_scanopt(mp->mnt_optnew, "dirmask", "%d", &v))
163 		pmp->pm_dirmask = v & ALLPERMS;
164 	vfs_flagopt(mp->mnt_optnew, "shortname",
165 	    &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
166 	vfs_flagopt(mp->mnt_optnew, "longname",
167 	    &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
168 	vfs_flagopt(mp->mnt_optnew, "kiconv",
169 	    &pmp->pm_flags, MSDOSFSMNT_KICONV);
170 
171 	/* XXX: Can't use flagopt due to negative option */
172 	if (!vfs_getopt(mp->mnt_optnew, "win95", NULL, NULL))
173 		pmp->pm_flags &= ~MSDOSFSMNT_NOWIN95;
174 	else
175 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
176 
177 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
178 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
179 	else if (!(pmp->pm_flags &
180 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
181 		struct vnode *rootvp;
182 
183 		/*
184 		 * Try to divine whether to support Win'95 long filenames
185 		 */
186 		if (FAT32(pmp))
187 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
188 		else {
189 			if ((error = msdosfs_root(mp, &rootvp, td)) != 0)
190 				return error;
191 			pmp->pm_flags |= findwin95(VTODE(rootvp))
192 				? MSDOSFSMNT_LONGNAME
193 					: MSDOSFSMNT_SHORTNAME;
194 			vput(rootvp);
195 		}
196 	}
197 	return 0;
198 }
199 
200 static int
201 msdosfs_cmount(struct mntarg *ma, void *data, int flags, struct thread *td)
202 {
203 	struct msdosfs_args args;
204 	int error;
205 
206 	if (data == NULL)
207 		return (EINVAL);
208 	error = copyin(data, &args, sizeof args);
209 	if (error)
210 		return (error);
211 
212 	ma = mount_argsu(ma, "from", args.fspec, MAXPATHLEN);
213 	ma = mount_arg(ma, "export", &args.export, sizeof args.export);
214 	ma = mount_argf(ma, "uid", "%d", args.uid);
215 	ma = mount_argf(ma, "gid", "%d", args.gid);
216 	ma = mount_argf(ma, "mask", "%d", args.mask);
217 	ma = mount_argf(ma, "dirmask", "%d", args.dirmask);
218 
219         ma = mount_argb(ma, args.flags & MSDOSFSMNT_SHORTNAME, "noshortname");
220         ma = mount_argb(ma, args.flags & MSDOSFSMNT_LONGNAME, "nolongname");
221         ma = mount_argb(ma, !(args.flags & MSDOSFSMNT_NOWIN95), "nowin95");
222         ma = mount_argb(ma, args.flags & MSDOSFSMNT_KICONV, "nokiconv");
223 
224         ma = mount_argsu(ma, "cs_win", args.cs_win, MAXCSLEN);
225         ma = mount_argsu(ma, "cs_dos", args.cs_dos, MAXCSLEN);
226         ma = mount_argsu(ma, "cs_local", args.cs_local, MAXCSLEN);
227 
228 	error = kernel_mount(ma, flags);
229 
230 	return (error);
231 }
232 
233 /*
234  * mp - path - addr in user space of mount point (ie /usr or whatever)
235  * data - addr in user space of mount params including the name of the block
236  * special file to treat as a filesystem.
237  */
238 static int
239 msdosfs_mount(struct mount *mp, struct thread *td)
240 {
241 	struct vnode *devvp;	  /* vnode for blk device to mount */
242 	struct export_args export;
243 	/* msdosfs specific mount control block */
244 	struct msdosfsmount *pmp = NULL;
245 	struct nameidata ndp;
246 	int error, flags;
247 	mode_t accessmode;
248 	char *from;
249 
250 	if (vfs_filteropt(mp->mnt_optnew, msdosfs_opts))
251 		return (EINVAL);
252 
253 	/*
254 	 * If updating, check whether changing from read-only to
255 	 * read/write; if there is no device name, that's all we do.
256 	 */
257 	if (mp->mnt_flag & MNT_UPDATE) {
258 		pmp = VFSTOMSDOSFS(mp);
259 
260 		error = vfs_copyopt(mp->mnt_optnew, "export",
261 		    &export, sizeof export);
262 		if (error == 0 && export.ex_flags != 0) {
263 			/*
264 			 * Process export requests.
265 			 */
266 			if ((export.ex_flags & MNT_EXPORTED) != 0 &&
267 			    (pmp->pm_flags & MSDOSFS_LARGEFS) != 0)
268 				return (EOPNOTSUPP);
269 			return (vfs_export(mp, &export));
270 		}
271 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) &&
272 		    vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
273 			error = VFS_SYNC(mp, MNT_WAIT, td);
274 			if (error)
275 				return (error);
276 			flags = WRITECLOSE;
277 			if (mp->mnt_flag & MNT_FORCE)
278 				flags |= FORCECLOSE;
279 			error = vflush(mp, 0, flags, td);
280 			if (error)
281 				return (error);
282 			DROP_GIANT();
283 			g_topology_lock();
284 			g_access(pmp->pm_cp, 0, -1, 0);
285 			g_topology_unlock();
286 			PICKUP_GIANT();
287 		} else if ((pmp->pm_flags & MSDOSFSMNT_RONLY) &&
288 		    !vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
289 			/*
290 			 * If upgrade to read-write by non-root, then verify
291 			 * that user has necessary permissions on the device.
292 			 */
293 			if (suser(td)) {
294 				devvp = pmp->pm_devvp;
295 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
296 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
297 						   td->td_ucred, td);
298 				if (error) {
299 					VOP_UNLOCK(devvp, 0, td);
300 					return (error);
301 				}
302 				VOP_UNLOCK(devvp, 0, td);
303 			}
304 			DROP_GIANT();
305 			g_topology_lock();
306 			error = g_access(pmp->pm_cp, 0, 1, 0);
307 			g_topology_unlock();
308 			PICKUP_GIANT();
309 			if (error)
310 				return (error);
311 
312 			/* Now that the volume is modifiable, mark it dirty. */
313 			error = markvoldirty(pmp, 1);
314 			if (error)
315 				return (error);
316 		}
317 		vfs_flagopt(mp->mnt_optnew, "ro",
318 		    &pmp->pm_flags, MSDOSFSMNT_RONLY);
319 		vfs_flagopt(mp->mnt_optnew, "ro",
320 		    &mp->mnt_flag, MNT_RDONLY);
321 		if (vfs_getopt(mp->mnt_optnew, "from", NULL, NULL)) {
322 #ifdef	__notyet__	/* doesn't work correctly with current mountd	XXX */
323 			if (args.flags & MSDOSFSMNT_MNTOPT) {
324 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
325 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
326 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
327 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
328 			}
329 #endif
330 		}
331 	}
332 	/*
333 	 * Not an update, or updating the name: look up the name
334 	 * and verify that it refers to a sensible disk device.
335 	 */
336 	if (vfs_getopt(mp->mnt_optnew, "from", (void **)&from, NULL))
337 		return (EINVAL);
338 	NDINIT(&ndp, LOOKUP, FOLLOW, UIO_SYSSPACE, from, td);
339 	error = namei(&ndp);
340 	if (error)
341 		return (error);
342 	devvp = ndp.ni_vp;
343 	NDFREE(&ndp, NDF_ONLY_PNBUF);
344 
345 	if (!vn_isdisk(devvp, &error)) {
346 		vrele(devvp);
347 		return (error);
348 	}
349 	/*
350 	 * If mount by non-root, then verify that user has necessary
351 	 * permissions on the device.
352 	 */
353 	if (suser(td)) {
354 		accessmode = VREAD;
355 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
356 			accessmode |= VWRITE;
357 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
358 		error = VOP_ACCESS(devvp, accessmode, td->td_ucred, td);
359 		if (error) {
360 			vput(devvp);
361 			return (error);
362 		}
363 		VOP_UNLOCK(devvp, 0, td);
364 	}
365 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
366 		error = mountmsdosfs(devvp, mp, td);
367 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
368 		pmp = VFSTOMSDOSFS(mp);
369 #endif
370 	} else {
371 		if (devvp != pmp->pm_devvp)
372 			error = EINVAL;	/* XXX needs translation */
373 		else
374 			vrele(devvp);
375 	}
376 	if (error) {
377 		vrele(devvp);
378 		return (error);
379 	}
380 
381 	error = update_mp(mp, td);
382 	if (error) {
383 		if ((mp->mnt_flag & MNT_UPDATE) == 0)
384 			msdosfs_unmount(mp, MNT_FORCE, td);
385 		return error;
386 	}
387 
388 	vfs_mountedfrom(mp, from);
389 #ifdef MSDOSFS_DEBUG
390 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
391 #endif
392 	return (0);
393 }
394 
395 static int
396 mountmsdosfs(devvp, mp, td)
397 	struct vnode *devvp;
398 	struct mount *mp;
399 	struct thread *td;
400 {
401 	struct msdosfsmount *pmp;
402 	struct buf *bp;
403 	struct cdev *dev = devvp->v_rdev;
404 	union bootsector *bsp;
405 	struct byte_bpb33 *b33;
406 	struct byte_bpb50 *b50;
407 	struct byte_bpb710 *b710;
408 	u_int8_t SecPerClust;
409 	u_long clusters;
410 	int	ronly, error;
411 	struct g_consumer *cp;
412 	struct bufobj *bo;
413 
414 	ronly = !vfs_getopt(mp->mnt_optnew, "ro", NULL, NULL);
415 	/* XXX: use VOP_ACCESS to check FS perms */
416 	DROP_GIANT();
417 	g_topology_lock();
418 	error = g_vfs_open(devvp, &cp, "msdos", ronly ? 0 : 1);
419 	g_topology_unlock();
420 	PICKUP_GIANT();
421 	VOP_UNLOCK(devvp, 0, td);
422 	if (error)
423 		return (error);
424 
425 	bo = &devvp->v_bufobj;
426 	bp  = NULL; /* both used in error_exit */
427 	pmp = NULL;
428 
429 	/*
430 	 * Read the boot sector of the filesystem, and then check the
431 	 * boot signature.  If not a dos boot sector then error out.
432 	 *
433 	 * NOTE: 2048 is a maximum sector size in current...
434 	 */
435 	error = bread(devvp, 0, 2048, NOCRED, &bp);
436 	if (error)
437 		goto error_exit;
438 	bp->b_flags |= B_AGE;
439 	bsp = (union bootsector *)bp->b_data;
440 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
441 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
442 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
443 
444 #ifndef MSDOSFS_NOCHECKSIG
445 	if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
446 	    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
447 		error = EINVAL;
448 		goto error_exit;
449 	}
450 #endif
451 
452 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
453 	pmp->pm_mountp = mp;
454 	pmp->pm_cp = cp;
455 	pmp->pm_bo = bo;
456 
457 	/*
458 	 * Compute several useful quantities from the bpb in the
459 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
460 	 * the fields that are different between dos 5 and dos 3.3.
461 	 */
462 	SecPerClust = b50->bpbSecPerClust;
463 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
464 	if (pmp->pm_BytesPerSec < DEV_BSIZE) {
465 		error = EINVAL;
466 		goto error_exit;
467 	}
468 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
469 	pmp->pm_FATs = b50->bpbFATs;
470 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
471 	pmp->pm_Sectors = getushort(b50->bpbSectors);
472 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
473 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
474 	pmp->pm_Heads = getushort(b50->bpbHeads);
475 	pmp->pm_Media = b50->bpbMedia;
476 
477 	/* calculate the ratio of sector size to DEV_BSIZE */
478 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
479 
480 	/* XXX - We should probably check more values here */
481 	if (!pmp->pm_BytesPerSec || !SecPerClust
482 		|| !pmp->pm_Heads
483 #ifdef PC98
484     		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) {
485 #else
486 		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
487 #endif
488 		error = EINVAL;
489 		goto error_exit;
490 	}
491 
492 	if (pmp->pm_Sectors == 0) {
493 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
494 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
495 	} else {
496 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
497 		pmp->pm_HugeSectors = pmp->pm_Sectors;
498 	}
499 #ifndef MSDOSFS_LARGE
500 	if (pmp->pm_HugeSectors > 0xffffffff /
501 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
502 		/*
503 		 * We cannot deal currently with this size of disk
504 		 * due to fileid limitations (see msdosfs_getattr and
505 		 * msdosfs_readdir)
506 		 */
507 		error = EINVAL;
508 		printf("mountmsdosfs(): disk too big, sorry\n");
509 		goto error_exit;
510 	}
511 #endif	/* !MSDOSFS_LARGE */
512 
513 	if (pmp->pm_RootDirEnts == 0) {
514 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
515 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
516 		    || pmp->pm_Sectors
517 		    || pmp->pm_FATsecs
518 		    || getushort(b710->bpbFSVers)) {
519 			error = EINVAL;
520 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
521 			goto error_exit;
522 		}
523 		pmp->pm_fatmask = FAT32_MASK;
524 		pmp->pm_fatmult = 4;
525 		pmp->pm_fatdiv = 1;
526 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
527 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
528 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
529 		else
530 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
531 	} else
532 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
533 
534 	/*
535 	 * Check a few values (could do some more):
536 	 * - logical sector size: power of 2, >= block size
537 	 * - sectors per cluster: power of 2, >= 1
538 	 * - number of sectors:   >= 1, <= size of partition
539 	 * - number of FAT sectors: >= 1
540 	 */
541 	if ( (SecPerClust == 0)
542 	  || (SecPerClust & (SecPerClust - 1))
543 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
544 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
545 	  || (pmp->pm_HugeSectors == 0)
546 	  || (pmp->pm_FATsecs == 0)
547 	) {
548 		error = EINVAL;
549 		goto error_exit;
550 	}
551 
552 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
553 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
554 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
555 	SecPerClust         *= pmp->pm_BlkPerSec;
556 
557 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
558 
559 	if (FAT32(pmp)) {
560 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
561 		pmp->pm_firstcluster = pmp->pm_fatblk
562 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
563 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
564 	} else {
565 		pmp->pm_rootdirblk = pmp->pm_fatblk +
566 			(pmp->pm_FATs * pmp->pm_FATsecs);
567 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
568 				       + DEV_BSIZE - 1)
569 			/ DEV_BSIZE; /* in blocks */
570 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
571 	}
572 
573 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
574 	    SecPerClust + 1;
575 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
576 
577 	if (pmp->pm_fatmask == 0) {
578 		if (pmp->pm_maxcluster
579 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
580 			/*
581 			 * This will usually be a floppy disk. This size makes
582 			 * sure that one fat entry will not be split across
583 			 * multiple blocks.
584 			 */
585 			pmp->pm_fatmask = FAT12_MASK;
586 			pmp->pm_fatmult = 3;
587 			pmp->pm_fatdiv = 2;
588 		} else {
589 			pmp->pm_fatmask = FAT16_MASK;
590 			pmp->pm_fatmult = 2;
591 			pmp->pm_fatdiv = 1;
592 		}
593 	}
594 
595 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
596 	if (pmp->pm_maxcluster >= clusters) {
597 		printf("Warning: number of clusters (%ld) exceeds FAT "
598 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
599 		pmp->pm_maxcluster = clusters - 1;
600 	}
601 
602 
603 	if (FAT12(pmp))
604 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
605 	else
606 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
607 
608 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
609 	pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
610 
611 	/*
612 	 * Compute mask and shift value for isolating cluster relative byte
613 	 * offsets and cluster numbers from a file offset.
614 	 */
615 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
616 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
617 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
618 
619 	/*
620 	 * Check for valid cluster size
621 	 * must be a power of 2
622 	 */
623 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
624 		error = EINVAL;
625 		goto error_exit;
626 	}
627 
628 	/*
629 	 * Release the bootsector buffer.
630 	 */
631 	brelse(bp);
632 	bp = NULL;
633 
634 	/*
635 	 * Check FSInfo.
636 	 */
637 	if (pmp->pm_fsinfo) {
638 		struct fsinfo *fp;
639 
640 		if ((error = bread(devvp, pmp->pm_fsinfo, fsi_size(pmp),
641 		    NOCRED, &bp)) != 0)
642 			goto error_exit;
643 		fp = (struct fsinfo *)bp->b_data;
644 		if (!bcmp(fp->fsisig1, "RRaA", 4)
645 		    && !bcmp(fp->fsisig2, "rrAa", 4)
646 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
647 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4)) {
648 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
649 			if (pmp->pm_nxtfree == 0xffffffff)
650 				pmp->pm_nxtfree = CLUST_FIRST;
651 		} else
652 			pmp->pm_fsinfo = 0;
653 		brelse(bp);
654 		bp = NULL;
655 	}
656 
657 	/*
658 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
659 	 */
660 	if (pmp->pm_fsinfo && pmp->pm_nxtfree > pmp->pm_maxcluster) {
661 		printf(
662 		"Next free cluster in FSInfo (%lu) exceeds maxcluster (%lu)\n",
663 		    pmp->pm_nxtfree, pmp->pm_maxcluster);
664 		error = EINVAL;
665 		goto error_exit;
666 	}
667 
668 	/*
669 	 * Allocate memory for the bitmap of allocated clusters, and then
670 	 * fill it in.
671 	 */
672 	pmp->pm_inusemap = malloc(howmany(pmp->pm_maxcluster + 1, N_INUSEBITS)
673 				  * sizeof(*pmp->pm_inusemap),
674 				  M_MSDOSFSFAT, M_WAITOK);
675 
676 	/*
677 	 * fillinusemap() needs pm_devvp.
678 	 */
679 	pmp->pm_dev = dev;
680 	pmp->pm_devvp = devvp;
681 
682 	/*
683 	 * Have the inuse map filled in.
684 	 */
685 	if ((error = fillinusemap(pmp)) != 0)
686 		goto error_exit;
687 
688 	/*
689 	 * If they want fat updates to be synchronous then let them suffer
690 	 * the performance degradation in exchange for the on disk copy of
691 	 * the fat being correct just about all the time.  I suppose this
692 	 * would be a good thing to turn on if the kernel is still flakey.
693 	 */
694 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
695 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
696 
697 	/*
698 	 * Finish up.
699 	 */
700 	if (ronly)
701 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
702 	else {
703 		/* Mark the volume dirty while it is mounted read/write. */
704 		if ((error = markvoldirty(pmp, 1)) != 0)
705 			goto error_exit;
706 		pmp->pm_fmod = 1;
707 	}
708 	mp->mnt_data = (qaddr_t) pmp;
709 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
710 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
711 	mp->mnt_flag |= MNT_LOCAL;
712 
713 #ifdef MSDOSFS_LARGE
714 	msdosfs_fileno_init(mp);
715 #endif
716 
717 	return 0;
718 
719 error_exit:
720 	if (bp)
721 		brelse(bp);
722 	if (cp != NULL) {
723 		DROP_GIANT();
724 		g_topology_lock();
725 		g_vfs_close(cp, td);
726 		g_topology_unlock();
727 		PICKUP_GIANT();
728 	}
729 	if (pmp) {
730 		if (pmp->pm_inusemap)
731 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
732 		free(pmp, M_MSDOSFSMNT);
733 		mp->mnt_data = (qaddr_t)0;
734 	}
735 	return (error);
736 }
737 
738 /*
739  * Unmount the filesystem described by mp.
740  */
741 static int
742 msdosfs_unmount(mp, mntflags, td)
743 	struct mount *mp;
744 	int mntflags;
745 	struct thread *td;
746 {
747 	struct msdosfsmount *pmp;
748 	int error, flags;
749 
750 	flags = 0;
751 	if (mntflags & MNT_FORCE)
752 		flags |= FORCECLOSE;
753 	error = vflush(mp, 0, flags, td);
754 	if (error)
755 		return error;
756 	pmp = VFSTOMSDOSFS(mp);
757 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
758 		if (pmp->pm_w2u)
759 			msdosfs_iconv->close(pmp->pm_w2u);
760 		if (pmp->pm_u2w)
761 			msdosfs_iconv->close(pmp->pm_u2w);
762 		if (pmp->pm_d2u)
763 			msdosfs_iconv->close(pmp->pm_d2u);
764 		if (pmp->pm_u2d)
765 			msdosfs_iconv->close(pmp->pm_u2d);
766 	}
767 
768 	/* If the volume was mounted read/write, mark it clean now. */
769 	if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) {
770 		error = markvoldirty(pmp, 0);
771 		if (error && (flags & FORCECLOSE) == 0)
772 			return (error);
773 	}
774 #ifdef MSDOSFS_DEBUG
775 	{
776 		struct vnode *vp = pmp->pm_devvp;
777 
778 		VI_LOCK(vp);
779 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
780 		printf("iflag %08lx, usecount %d, writecount %d, holdcnt %ld\n",
781 		    vp->vi_flag, vp->v_usecount, vp->v_writecount,
782 		    vp->v_holdcnt);
783 		printf("id %lu, mount %p, op %p\n",
784 		    vp->v_id, vp->v_mount, vp->v_op);
785 		printf("freef %p, freeb %p, mount %p\n",
786 		    TAILQ_NEXT(vp, v_freelist), vp->v_freelist.tqe_prev,
787 		    vp->v_mount);
788 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
789 		    TAILQ_FIRST(&vp->v_bufobj.bo_clean.bv_hd),
790 		    TAILQ_FIRST(&vp->v_bufobj.bo_dirty.bv_hd),
791 		    vp->v_bufobj.bo_numoutput, vp->v_type);
792 		printf("union %p, tag %s, data[0] %08x, data[1] %08x\n",
793 		    vp->v_socket, vp->v_tag,
794 		    ((u_int *)vp->v_data)[0],
795 		    ((u_int *)vp->v_data)[1]);
796 		VI_UNLOCK(vp);
797 	}
798 #endif
799 	DROP_GIANT();
800 	g_topology_lock();
801 	g_vfs_close(pmp->pm_cp, td);
802 	g_topology_unlock();
803 	PICKUP_GIANT();
804 	vrele(pmp->pm_devvp);
805 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
806 #ifdef MSDOSFS_LARGE
807 	msdosfs_fileno_free(mp);
808 #endif
809 	free(pmp, M_MSDOSFSMNT);
810 	mp->mnt_data = (qaddr_t)0;
811 	mp->mnt_flag &= ~MNT_LOCAL;
812 	return (error);
813 }
814 
815 static int
816 msdosfs_root(mp, vpp, td)
817 	struct mount *mp;
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_XLOCK)) {
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_init =		msdosfs_init,
967 	.vfs_mount =		msdosfs_mount,
968 	.vfs_cmount =		msdosfs_cmount,
969 	.vfs_root =		msdosfs_root,
970 	.vfs_statfs =		msdosfs_statfs,
971 	.vfs_sync =		msdosfs_sync,
972 	.vfs_uninit =		msdosfs_uninit,
973 	.vfs_unmount =		msdosfs_unmount,
974 	.vfs_vptofh =		msdosfs_vptofh,
975 };
976 
977 VFS_SET(msdosfs_vfsops, msdosfs, 0);
978 MODULE_VERSION(msdosfs, 1);
979