xref: /freebsd/sys/fs/msdosfs/msdosfs_vfsops.c (revision 7dfd9569a2f0637fb9a48157b1c1bfe5709faee3)
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", "shortnames", "longname", "longnames", "nowin95", "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, "shortnames",
167 	    &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
168 	vfs_flagopt(mp->mnt_optnew, "longname",
169 	    &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
170 	vfs_flagopt(mp->mnt_optnew, "longnames",
171 	    &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
172 	vfs_flagopt(mp->mnt_optnew, "kiconv",
173 	    &pmp->pm_flags, MSDOSFSMNT_KICONV);
174 
175 	if (vfs_getopt(mp->mnt_optnew, "nowin95", NULL, NULL) == 0)
176 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
177 	else
178 		pmp->pm_flags &= ~MSDOSFSMNT_NOWIN95;
179 
180 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
181 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
182 	else if (!(pmp->pm_flags &
183 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
184 		struct vnode *rootvp;
185 
186 		/*
187 		 * Try to divine whether to support Win'95 long filenames
188 		 */
189 		if (FAT32(pmp))
190 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
191 		else {
192 			if ((error =
193 			    msdosfs_root(mp, LK_EXCLUSIVE, &rootvp, td)) != 0)
194 				return error;
195 			pmp->pm_flags |= findwin95(VTODE(rootvp))
196 				? MSDOSFSMNT_LONGNAME
197 					: MSDOSFSMNT_SHORTNAME;
198 			vput(rootvp);
199 		}
200 	}
201 	return 0;
202 }
203 
204 static int
205 msdosfs_cmount(struct mntarg *ma, void *data, int flags, struct thread *td)
206 {
207 	struct msdosfs_args args;
208 	int error;
209 
210 	if (data == NULL)
211 		return (EINVAL);
212 	error = copyin(data, &args, sizeof args);
213 	if (error)
214 		return (error);
215 
216 	ma = mount_argsu(ma, "from", args.fspec, MAXPATHLEN);
217 	ma = mount_arg(ma, "export", &args.export, sizeof args.export);
218 	ma = mount_argf(ma, "uid", "%d", args.uid);
219 	ma = mount_argf(ma, "gid", "%d", args.gid);
220 	ma = mount_argf(ma, "mask", "%d", args.mask);
221 	ma = mount_argf(ma, "dirmask", "%d", args.dirmask);
222 
223         ma = mount_argb(ma, args.flags & MSDOSFSMNT_SHORTNAME, "noshortname");
224         ma = mount_argb(ma, args.flags & MSDOSFSMNT_LONGNAME, "nolongname");
225         ma = mount_argb(ma, !(args.flags & MSDOSFSMNT_NOWIN95), "nowin95");
226         ma = mount_argb(ma, args.flags & MSDOSFSMNT_KICONV, "nokiconv");
227 
228         ma = mount_argsu(ma, "cs_win", args.cs_win, MAXCSLEN);
229         ma = mount_argsu(ma, "cs_dos", args.cs_dos, MAXCSLEN);
230         ma = mount_argsu(ma, "cs_local", args.cs_local, MAXCSLEN);
231 
232 	error = kernel_mount(ma, flags);
233 
234 	return (error);
235 }
236 
237 /*
238  * mp - path - addr in user space of mount point (ie /usr or whatever)
239  * data - addr in user space of mount params including the name of the block
240  * special file to treat as a filesystem.
241  */
242 static int
243 msdosfs_mount(struct mount *mp, struct thread *td)
244 {
245 	struct vnode *devvp;	  /* vnode for blk device to mount */
246 	struct export_args export;
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 		error = vfs_copyopt(mp->mnt_optnew, "export",
265 		    &export, sizeof export);
266 		if (error == 0 && export.ex_flags != 0) {
267 			/*
268 			 * Process export requests.
269 			 */
270 			if ((export.ex_flags & MNT_EXPORTED) != 0 &&
271 			    (pmp->pm_flags & MSDOSFS_LARGEFS) != 0)
272 				return (EOPNOTSUPP);
273 			return (vfs_export(mp, &export));
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 		} else if ((pmp->pm_flags & MSDOSFSMNT_RONLY) &&
292 		    !vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
293 			/*
294 			 * If upgrade to read-write by non-root, then verify
295 			 * that user has necessary permissions on the device.
296 			 */
297 			if (suser(td)) {
298 				devvp = pmp->pm_devvp;
299 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
300 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
301 						   td->td_ucred, td);
302 				if (error) {
303 					VOP_UNLOCK(devvp, 0, td);
304 					return (error);
305 				}
306 				VOP_UNLOCK(devvp, 0, td);
307 			}
308 			DROP_GIANT();
309 			g_topology_lock();
310 			error = g_access(pmp->pm_cp, 0, 1, 0);
311 			g_topology_unlock();
312 			PICKUP_GIANT();
313 			if (error)
314 				return (error);
315 
316 			/* Now that the volume is modifiable, mark it dirty. */
317 			error = markvoldirty(pmp, 1);
318 			if (error)
319 				return (error);
320 		}
321 		vfs_flagopt(mp->mnt_optnew, "ro",
322 		    &pmp->pm_flags, MSDOSFSMNT_RONLY);
323 		vfs_flagopt(mp->mnt_optnew, "ro",
324 		    &mp->mnt_flag, MNT_RDONLY);
325 		if (vfs_getopt(mp->mnt_optnew, "from", NULL, NULL)) {
326 #ifdef	__notyet__	/* doesn't work correctly with current mountd	XXX */
327 			if (args.flags & MSDOSFSMNT_MNTOPT) {
328 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
329 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
330 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
331 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
332 			}
333 #endif
334 		}
335 	}
336 	/*
337 	 * Not an update, or updating the name: look up the name
338 	 * and verify that it refers to a sensible disk device.
339 	 */
340 	if (vfs_getopt(mp->mnt_optnew, "from", (void **)&from, NULL))
341 		return (EINVAL);
342 	NDINIT(&ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, from, td);
343 	error = namei(&ndp);
344 	if (error)
345 		return (error);
346 	devvp = ndp.ni_vp;
347 	NDFREE(&ndp, NDF_ONLY_PNBUF);
348 
349 	if (!vn_isdisk(devvp, &error)) {
350 		vput(devvp);
351 		return (error);
352 	}
353 	/*
354 	 * If mount by non-root, then verify that user has necessary
355 	 * permissions on the device.
356 	 */
357 	if (suser(td)) {
358 		accessmode = VREAD;
359 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
360 			accessmode |= VWRITE;
361 		error = VOP_ACCESS(devvp, accessmode, td->td_ucred, td);
362 		if (error) {
363 			vput(devvp);
364 			return (error);
365 		}
366 	}
367 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
368 		error = mountmsdosfs(devvp, mp, td);
369 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
370 		pmp = VFSTOMSDOSFS(mp);
371 #endif
372 	} else {
373 		if (devvp != pmp->pm_devvp)
374 			error = EINVAL;	/* XXX needs translation */
375 		else
376 			vput(devvp);
377 	}
378 	if (error) {
379 		vrele(devvp);
380 		return (error);
381 	}
382 
383 	error = update_mp(mp, td);
384 	if (error) {
385 		if ((mp->mnt_flag & MNT_UPDATE) == 0)
386 			msdosfs_unmount(mp, MNT_FORCE, td);
387 		return error;
388 	}
389 
390 	vfs_mountedfrom(mp, from);
391 #ifdef MSDOSFS_DEBUG
392 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
393 #endif
394 	return (0);
395 }
396 
397 static int
398 mountmsdosfs(devvp, mp, td)
399 	struct vnode *devvp;
400 	struct mount *mp;
401 	struct thread *td;
402 {
403 	struct msdosfsmount *pmp;
404 	struct buf *bp;
405 	struct cdev *dev = devvp->v_rdev;
406 	union bootsector *bsp;
407 	struct byte_bpb33 *b33;
408 	struct byte_bpb50 *b50;
409 	struct byte_bpb710 *b710;
410 	u_int8_t SecPerClust;
411 	u_long clusters;
412 	int	ronly, error;
413 	struct g_consumer *cp;
414 	struct bufobj *bo;
415 
416 	ronly = !vfs_getopt(mp->mnt_optnew, "ro", NULL, NULL);
417 	/* XXX: use VOP_ACCESS to check FS perms */
418 	DROP_GIANT();
419 	g_topology_lock();
420 	error = g_vfs_open(devvp, &cp, "msdos", ronly ? 0 : 1);
421 	g_topology_unlock();
422 	PICKUP_GIANT();
423 	VOP_UNLOCK(devvp, 0, td);
424 	if (error)
425 		return (error);
426 
427 	bo = &devvp->v_bufobj;
428 	bp  = NULL; /* both used in error_exit */
429 	pmp = NULL;
430 
431 	/*
432 	 * Read the boot sector of the filesystem, and then check the
433 	 * boot signature.  If not a dos boot sector then error out.
434 	 *
435 	 * NOTE: 2048 is a maximum sector size in current...
436 	 */
437 	error = bread(devvp, 0, 2048, NOCRED, &bp);
438 	if (error)
439 		goto error_exit;
440 	bp->b_flags |= B_AGE;
441 	bsp = (union bootsector *)bp->b_data;
442 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
443 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
444 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
445 
446 #ifndef MSDOSFS_NOCHECKSIG
447 	if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
448 	    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
449 		error = EINVAL;
450 		goto error_exit;
451 	}
452 #endif
453 
454 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
455 	pmp->pm_mountp = mp;
456 	pmp->pm_cp = cp;
457 	pmp->pm_bo = bo;
458 
459 	/*
460 	 * Compute several useful quantities from the bpb in the
461 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
462 	 * the fields that are different between dos 5 and dos 3.3.
463 	 */
464 	SecPerClust = b50->bpbSecPerClust;
465 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
466 	if (pmp->pm_BytesPerSec < DEV_BSIZE) {
467 		error = EINVAL;
468 		goto error_exit;
469 	}
470 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
471 	pmp->pm_FATs = b50->bpbFATs;
472 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
473 	pmp->pm_Sectors = getushort(b50->bpbSectors);
474 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
475 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
476 	pmp->pm_Heads = getushort(b50->bpbHeads);
477 	pmp->pm_Media = b50->bpbMedia;
478 
479 	/* calculate the ratio of sector size to DEV_BSIZE */
480 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
481 
482 	/* XXX - We should probably check more values here */
483 	if (!pmp->pm_BytesPerSec || !SecPerClust
484 		|| !pmp->pm_Heads
485 #ifdef PC98
486     		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) {
487 #else
488 		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
489 #endif
490 		error = EINVAL;
491 		goto error_exit;
492 	}
493 
494 	if (pmp->pm_Sectors == 0) {
495 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
496 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
497 	} else {
498 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
499 		pmp->pm_HugeSectors = pmp->pm_Sectors;
500 	}
501 #ifndef MSDOSFS_LARGE
502 	if (pmp->pm_HugeSectors > 0xffffffff /
503 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
504 		/*
505 		 * We cannot deal currently with this size of disk
506 		 * due to fileid limitations (see msdosfs_getattr and
507 		 * msdosfs_readdir)
508 		 */
509 		error = EINVAL;
510 		printf("mountmsdosfs(): disk too big, sorry\n");
511 		goto error_exit;
512 	}
513 #endif	/* !MSDOSFS_LARGE */
514 
515 	if (pmp->pm_RootDirEnts == 0) {
516 		if (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_devvp = devvp;
680 
681 	/*
682 	 * Have the inuse map filled in.
683 	 */
684 	if ((error = fillinusemap(pmp)) != 0)
685 		goto error_exit;
686 
687 	/*
688 	 * If they want fat updates to be synchronous then let them suffer
689 	 * the performance degradation in exchange for the on disk copy of
690 	 * the fat being correct just about all the time.  I suppose this
691 	 * would be a good thing to turn on if the kernel is still flakey.
692 	 */
693 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
694 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
695 
696 	/*
697 	 * Finish up.
698 	 */
699 	if (ronly)
700 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
701 	else {
702 		/* Mark the volume dirty while it is mounted read/write. */
703 		if ((error = markvoldirty(pmp, 1)) != 0)
704 			goto error_exit;
705 		pmp->pm_fmod = 1;
706 	}
707 	mp->mnt_data = (qaddr_t) pmp;
708 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
709 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
710 	mp->mnt_flag |= MNT_LOCAL;
711 
712 #ifdef MSDOSFS_LARGE
713 	msdosfs_fileno_init(mp);
714 #endif
715 
716 	return 0;
717 
718 error_exit:
719 	if (bp)
720 		brelse(bp);
721 	if (cp != NULL) {
722 		DROP_GIANT();
723 		g_topology_lock();
724 		g_vfs_close(cp, td);
725 		g_topology_unlock();
726 		PICKUP_GIANT();
727 	}
728 	if (pmp) {
729 		if (pmp->pm_inusemap)
730 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
731 		free(pmp, M_MSDOSFSMNT);
732 		mp->mnt_data = (qaddr_t)0;
733 	}
734 	return (error);
735 }
736 
737 /*
738  * Unmount the filesystem described by mp.
739  */
740 static int
741 msdosfs_unmount(mp, mntflags, td)
742 	struct mount *mp;
743 	int mntflags;
744 	struct thread *td;
745 {
746 	struct msdosfsmount *pmp;
747 	int error, flags;
748 
749 	flags = 0;
750 	if (mntflags & MNT_FORCE)
751 		flags |= FORCECLOSE;
752 	error = vflush(mp, 0, flags, td);
753 	if (error)
754 		return error;
755 	pmp = VFSTOMSDOSFS(mp);
756 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
757 		if (pmp->pm_w2u)
758 			msdosfs_iconv->close(pmp->pm_w2u);
759 		if (pmp->pm_u2w)
760 			msdosfs_iconv->close(pmp->pm_u2w);
761 		if (pmp->pm_d2u)
762 			msdosfs_iconv->close(pmp->pm_d2u);
763 		if (pmp->pm_u2d)
764 			msdosfs_iconv->close(pmp->pm_u2d);
765 	}
766 
767 	/* If the volume was mounted read/write, mark it clean now. */
768 	if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) {
769 		error = markvoldirty(pmp, 0);
770 		if (error && (flags & FORCECLOSE) == 0)
771 			return (error);
772 	}
773 #ifdef MSDOSFS_DEBUG
774 	{
775 		struct vnode *vp = pmp->pm_devvp;
776 
777 		VI_LOCK(vp);
778 		vn_printf(vp,
779 		    "msdosfs_umount(): just before calling VOP_CLOSE()\n");
780 		printf("freef %p, freeb %p, mount %p\n",
781 		    TAILQ_NEXT(vp, v_freelist), vp->v_freelist.tqe_prev,
782 		    vp->v_mount);
783 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
784 		    TAILQ_FIRST(&vp->v_bufobj.bo_clean.bv_hd),
785 		    TAILQ_FIRST(&vp->v_bufobj.bo_dirty.bv_hd),
786 		    vp->v_bufobj.bo_numoutput, vp->v_type);
787 		VI_UNLOCK(vp);
788 	}
789 #endif
790 	DROP_GIANT();
791 	g_topology_lock();
792 	g_vfs_close(pmp->pm_cp, td);
793 	g_topology_unlock();
794 	PICKUP_GIANT();
795 	vrele(pmp->pm_devvp);
796 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
797 #ifdef MSDOSFS_LARGE
798 	msdosfs_fileno_free(mp);
799 #endif
800 	free(pmp, M_MSDOSFSMNT);
801 	mp->mnt_data = (qaddr_t)0;
802 	mp->mnt_flag &= ~MNT_LOCAL;
803 	return (error);
804 }
805 
806 static int
807 msdosfs_root(mp, flags, vpp, td)
808 	struct mount *mp;
809 	int flags;
810 	struct vnode **vpp;
811 	struct thread *td;
812 {
813 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
814 	struct denode *ndep;
815 	int error;
816 
817 #ifdef MSDOSFS_DEBUG
818 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
819 #endif
820 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
821 	if (error)
822 		return (error);
823 	*vpp = DETOV(ndep);
824 	return (0);
825 }
826 
827 static int
828 msdosfs_statfs(mp, sbp, td)
829 	struct mount *mp;
830 	struct statfs *sbp;
831 	struct thread *td;
832 {
833 	struct msdosfsmount *pmp;
834 
835 	pmp = VFSTOMSDOSFS(mp);
836 	sbp->f_bsize = pmp->pm_bpcluster;
837 	sbp->f_iosize = pmp->pm_bpcluster;
838 	sbp->f_blocks = pmp->pm_maxcluster + 1;
839 	sbp->f_bfree = pmp->pm_freeclustercount;
840 	sbp->f_bavail = pmp->pm_freeclustercount;
841 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
842 	sbp->f_ffree = 0;	/* what to put in here? */
843 	return (0);
844 }
845 
846 static int
847 msdosfs_sync(mp, waitfor, td)
848 	struct mount *mp;
849 	int waitfor;
850 	struct thread *td;
851 {
852 	struct vnode *vp, *nvp;
853 	struct denode *dep;
854 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
855 	int error, allerror = 0;
856 
857 	/*
858 	 * If we ever switch to not updating all of the fats all the time,
859 	 * this would be the place to update them from the first one.
860 	 */
861 	if (pmp->pm_fmod != 0) {
862 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
863 			panic("msdosfs_sync: rofs mod");
864 		else {
865 			/* update fats here */
866 		}
867 	}
868 	/*
869 	 * Write back each (modified) denode.
870 	 */
871 	MNT_ILOCK(mp);
872 loop:
873 	MNT_VNODE_FOREACH(vp, mp, nvp) {
874 		VI_LOCK(vp);
875 		if (vp->v_type == VNON || (vp->v_iflag & VI_DOOMED)) {
876 			VI_UNLOCK(vp);
877 			continue;
878 		}
879 		MNT_IUNLOCK(mp);
880 		dep = VTODE(vp);
881 		if ((dep->de_flag &
882 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
883 		    (vp->v_bufobj.bo_dirty.bv_cnt == 0 ||
884 		    waitfor == MNT_LAZY)) {
885 			VI_UNLOCK(vp);
886 			MNT_ILOCK(mp);
887 			continue;
888 		}
889 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, td);
890 		if (error) {
891 			MNT_ILOCK(mp);
892 			if (error == ENOENT)
893 				goto loop;
894 			continue;
895 		}
896 		error = VOP_FSYNC(vp, waitfor, td);
897 		if (error)
898 			allerror = error;
899 		VOP_UNLOCK(vp, 0, td);
900 		vrele(vp);
901 		MNT_ILOCK(mp);
902 	}
903 	MNT_IUNLOCK(mp);
904 
905 	/*
906 	 * Flush filesystem control info.
907 	 */
908 	if (waitfor != MNT_LAZY) {
909 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY, td);
910 		error = VOP_FSYNC(pmp->pm_devvp, waitfor, td);
911 		if (error)
912 			allerror = error;
913 		VOP_UNLOCK(pmp->pm_devvp, 0, td);
914 	}
915 	return (allerror);
916 }
917 
918 static int
919 msdosfs_fhtovp(mp, fhp, vpp)
920 	struct mount *mp;
921 	struct fid *fhp;
922 	struct vnode **vpp;
923 {
924 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
925 	struct defid *defhp = (struct defid *) fhp;
926 	struct denode *dep;
927 	int error;
928 
929 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
930 	if (error) {
931 		*vpp = NULLVP;
932 		return (error);
933 	}
934 	*vpp = DETOV(dep);
935 	vnode_create_vobject(*vpp, dep->de_FileSize, curthread);
936 	return (0);
937 }
938 
939 static int
940 msdosfs_vptofh(vp, fhp)
941 	struct vnode *vp;
942 	struct fid *fhp;
943 {
944 	struct denode *dep;
945 	struct defid *defhp;
946 
947 	dep = VTODE(vp);
948 	defhp = (struct defid *)fhp;
949 	defhp->defid_len = sizeof(struct defid);
950 	defhp->defid_dirclust = dep->de_dirclust;
951 	defhp->defid_dirofs = dep->de_diroffset;
952 	/* defhp->defid_gen = dep->de_gen; */
953 	return (0);
954 }
955 
956 static struct vfsops msdosfs_vfsops = {
957 	.vfs_fhtovp =		msdosfs_fhtovp,
958 	.vfs_mount =		msdosfs_mount,
959 	.vfs_cmount =		msdosfs_cmount,
960 	.vfs_root =		msdosfs_root,
961 	.vfs_statfs =		msdosfs_statfs,
962 	.vfs_sync =		msdosfs_sync,
963 	.vfs_unmount =		msdosfs_unmount,
964 	.vfs_vptofh =		msdosfs_vptofh,
965 };
966 
967 VFS_SET(msdosfs_vfsops, msdosfs, 0);
968 MODULE_VERSION(msdosfs, 1);
969