xref: /freebsd/sys/fs/msdosfs/msdosfs_vfsops.c (revision a9148abd9da5db2f1c682fb17bed791845fc41c9)
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/buf.h>
54 #include <sys/conf.h>
55 #include <sys/fcntl.h>
56 #include <sys/iconv.h>
57 #include <sys/kernel.h>
58 #include <sys/lock.h>
59 #include <sys/malloc.h>
60 #include <sys/mount.h>
61 #include <sys/mutex.h>
62 #include <sys/namei.h>
63 #include <sys/priv.h>
64 #include <sys/proc.h>
65 #include <sys/stat.h>
66 #include <sys/vnode.h>
67 
68 #include <geom/geom.h>
69 #include <geom/geom_vfs.h>
70 
71 #include <fs/msdosfs/bootsect.h>
72 #include <fs/msdosfs/bpb.h>
73 #include <fs/msdosfs/direntry.h>
74 #include <fs/msdosfs/denode.h>
75 #include <fs/msdosfs/fat.h>
76 #include <fs/msdosfs/msdosfsmount.h>
77 
78 /* Mount options that we support. */
79 static const char *msdosfs_opts[] = {
80 	"async", "noatime", "noclusterr", "noclusterw",
81 	"export", "force", "from", "sync",
82 	"cs_dos", "cs_local", "cs_win", "dirmask",
83 	"gid", "kiconv", "large", "longname",
84 	"longnames", "mask", "shortname", "shortnames",
85 	"uid", "win95", "nowin95",
86 	NULL
87 };
88 
89 #if 1 /*def PC98*/
90 /*
91  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
92  *       garbage or a random value :-{
93  *       If you want to use that broken-signatured media, define the
94  *       following symbol even though PC/AT.
95  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
96  */
97 #define	MSDOSFS_NOCHECKSIG
98 #endif
99 
100 MALLOC_DEFINE(M_MSDOSFSMNT, "msdosfs_mount", "MSDOSFS mount structure");
101 static MALLOC_DEFINE(M_MSDOSFSFAT, "msdosfs_fat", "MSDOSFS file allocation table");
102 
103 struct iconv_functions *msdosfs_iconv;
104 
105 static int	update_mp(struct mount *mp, struct thread *td);
106 static int	mountmsdosfs(struct vnode *devvp, struct mount *mp);
107 static vfs_fhtovp_t	msdosfs_fhtovp;
108 static vfs_mount_t	msdosfs_mount;
109 static vfs_root_t	msdosfs_root;
110 static vfs_statfs_t	msdosfs_statfs;
111 static vfs_sync_t	msdosfs_sync;
112 static vfs_unmount_t	msdosfs_unmount;
113 
114 /* Maximum length of a character set name (arbitrary). */
115 #define	MAXCSLEN	64
116 
117 static int
118 update_mp(struct mount *mp, struct thread *td)
119 {
120 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
121 	void *dos, *win, *local;
122 	int error, v;
123 
124 	if (!vfs_getopt(mp->mnt_optnew, "kiconv", NULL, NULL)) {
125 		if (msdosfs_iconv != NULL) {
126 			error = vfs_getopt(mp->mnt_optnew,
127 			    "cs_win", &win, NULL);
128 			if (!error)
129 				error = vfs_getopt(mp->mnt_optnew,
130 				    "cs_local", &local, NULL);
131 			if (!error)
132 				error = vfs_getopt(mp->mnt_optnew,
133 				    "cs_dos", &dos, NULL);
134 			if (!error) {
135 				msdosfs_iconv->open(win, local, &pmp->pm_u2w);
136 				msdosfs_iconv->open(local, win, &pmp->pm_w2u);
137 				msdosfs_iconv->open(dos, local, &pmp->pm_u2d);
138 				msdosfs_iconv->open(local, dos, &pmp->pm_d2u);
139 			}
140 			if (error != 0)
141 				return (error);
142 		} else {
143 			pmp->pm_w2u = NULL;
144 			pmp->pm_u2w = NULL;
145 			pmp->pm_d2u = NULL;
146 			pmp->pm_u2d = NULL;
147 		}
148 	}
149 
150 	if (1 == vfs_scanopt(mp->mnt_optnew, "gid", "%d", &v))
151 		pmp->pm_gid = v;
152 	if (1 == vfs_scanopt(mp->mnt_optnew, "uid", "%d", &v))
153 		pmp->pm_uid = v;
154 	if (1 == vfs_scanopt(mp->mnt_optnew, "mask", "%d", &v))
155 		pmp->pm_mask = v & ALLPERMS;
156 	if (1 == vfs_scanopt(mp->mnt_optnew, "dirmask", "%d", &v))
157 		pmp->pm_dirmask = v & ALLPERMS;
158 	vfs_flagopt(mp->mnt_optnew, "shortname",
159 	    &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
160 	vfs_flagopt(mp->mnt_optnew, "shortnames",
161 	    &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
162 	vfs_flagopt(mp->mnt_optnew, "longname",
163 	    &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
164 	vfs_flagopt(mp->mnt_optnew, "longnames",
165 	    &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
166 	vfs_flagopt(mp->mnt_optnew, "kiconv",
167 	    &pmp->pm_flags, MSDOSFSMNT_KICONV);
168 
169 	if (vfs_getopt(mp->mnt_optnew, "nowin95", NULL, NULL) == 0)
170 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
171 	else
172 		pmp->pm_flags &= ~MSDOSFSMNT_NOWIN95;
173 
174 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
175 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
176 	else if (!(pmp->pm_flags &
177 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
178 		struct vnode *rootvp;
179 
180 		/*
181 		 * Try to divine whether to support Win'95 long filenames
182 		 */
183 		if (FAT32(pmp))
184 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
185 		else {
186 			if ((error =
187 			    msdosfs_root(mp, LK_EXCLUSIVE, &rootvp, td)) != 0)
188 				return error;
189 			pmp->pm_flags |= findwin95(VTODE(rootvp)) ?
190 			    MSDOSFSMNT_LONGNAME : MSDOSFSMNT_SHORTNAME;
191 			vput(rootvp);
192 		}
193 	}
194 	return 0;
195 }
196 
197 static int
198 msdosfs_cmount(struct mntarg *ma, void *data, int flags, struct thread *td)
199 {
200 	struct msdosfs_args args;
201 	int error;
202 
203 	if (data == NULL)
204 		return (EINVAL);
205 	error = copyin(data, &args, sizeof args);
206 	if (error)
207 		return (error);
208 
209 	ma = mount_argsu(ma, "from", args.fspec, MAXPATHLEN);
210 	ma = mount_arg(ma, "export", &args.export, sizeof args.export);
211 	ma = mount_argf(ma, "uid", "%d", args.uid);
212 	ma = mount_argf(ma, "gid", "%d", args.gid);
213 	ma = mount_argf(ma, "mask", "%d", args.mask);
214 	ma = mount_argf(ma, "dirmask", "%d", args.dirmask);
215 
216 	ma = mount_argb(ma, args.flags & MSDOSFSMNT_SHORTNAME, "noshortname");
217 	ma = mount_argb(ma, args.flags & MSDOSFSMNT_LONGNAME, "nolongname");
218 	ma = mount_argb(ma, !(args.flags & MSDOSFSMNT_NOWIN95), "nowin95");
219 	ma = mount_argb(ma, args.flags & MSDOSFSMNT_KICONV, "nokiconv");
220 
221 	ma = mount_argsu(ma, "cs_win", args.cs_win, MAXCSLEN);
222 	ma = mount_argsu(ma, "cs_dos", args.cs_dos, MAXCSLEN);
223 	ma = mount_argsu(ma, "cs_local", args.cs_local, MAXCSLEN);
224 
225 	error = kernel_mount(ma, flags);
226 
227 	return (error);
228 }
229 
230 /*
231  * mp - path - addr in user space of mount point (ie /usr or whatever)
232  * data - addr in user space of mount params including the name of the block
233  * special file to treat as a filesystem.
234  */
235 static int
236 msdosfs_mount(struct mount *mp, struct thread *td)
237 {
238 	struct vnode *devvp;	  /* vnode for blk device to mount */
239 	/* msdosfs specific mount control block */
240 	struct msdosfsmount *pmp = NULL;
241 	struct nameidata ndp;
242 	int error, flags;
243 	accmode_t accmode;
244 	char *from;
245 
246 	if (vfs_filteropt(mp->mnt_optnew, msdosfs_opts))
247 		return (EINVAL);
248 
249 	/*
250 	 * If updating, check whether changing from read-only to
251 	 * read/write; if there is no device name, that's all we do.
252 	 */
253 	if (mp->mnt_flag & MNT_UPDATE) {
254 		pmp = VFSTOMSDOSFS(mp);
255 		if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0)) {
256 			/*
257 			 * Forbid export requests if filesystem has
258 			 * MSDOSFS_LARGEFS flag set.
259 			 */
260 			if ((pmp->pm_flags & MSDOSFS_LARGEFS) != 0) {
261 				vfs_mount_error(mp,
262 				    "MSDOSFS_LARGEFS flag set, cannot export");
263 				return (EOPNOTSUPP);
264 			}
265 		}
266 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) &&
267 		    vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
268 			error = VFS_SYNC(mp, MNT_WAIT, td);
269 			if (error)
270 				return (error);
271 			flags = WRITECLOSE;
272 			if (mp->mnt_flag & MNT_FORCE)
273 				flags |= FORCECLOSE;
274 			error = vflush(mp, 0, flags, td);
275 			if (error)
276 				return (error);
277 
278 			/*
279 			 * Now the volume is clean.  Mark it so while the
280 			 * device is still rw.
281 			 */
282 			error = markvoldirty(pmp, 0);
283 			if (error) {
284 				(void)markvoldirty(pmp, 1);
285 				return (error);
286 			}
287 
288 			/* Downgrade the device from rw to ro. */
289 			DROP_GIANT();
290 			g_topology_lock();
291 			error = g_access(pmp->pm_cp, 0, -1, 0);
292 			g_topology_unlock();
293 			PICKUP_GIANT();
294 			if (error) {
295 				(void)markvoldirty(pmp, 1);
296 				return (error);
297 			}
298 
299 			/*
300 			 * Backing out after an error was painful in the
301 			 * above.  Now we are committed to succeeding.
302 			 */
303 			pmp->pm_fmod = 0;
304 			pmp->pm_flags |= MSDOSFSMNT_RONLY;
305 			MNT_ILOCK(mp);
306 			mp->mnt_flag |= MNT_RDONLY;
307 			MNT_IUNLOCK(mp);
308 		} else if ((pmp->pm_flags & MSDOSFSMNT_RONLY) &&
309 		    !vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
310 			/*
311 			 * If upgrade to read-write by non-root, then verify
312 			 * that user has necessary permissions on the device.
313 			 */
314 			devvp = pmp->pm_devvp;
315 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
316 			error = VOP_ACCESS(devvp, VREAD | VWRITE,
317 			    td->td_ucred, td);
318 			if (error)
319 				error = priv_check(td, PRIV_VFS_MOUNT_PERM);
320 			if (error) {
321 				VOP_UNLOCK(devvp, 0);
322 				return (error);
323 			}
324 			VOP_UNLOCK(devvp, 0);
325 			DROP_GIANT();
326 			g_topology_lock();
327 			error = g_access(pmp->pm_cp, 0, 1, 0);
328 			g_topology_unlock();
329 			PICKUP_GIANT();
330 			if (error)
331 				return (error);
332 
333 			pmp->pm_fmod = 1;
334 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
335 			MNT_ILOCK(mp);
336 			mp->mnt_flag &= ~MNT_RDONLY;
337 			MNT_IUNLOCK(mp);
338 
339 			/* Now that the volume is modifiable, mark it dirty. */
340 			error = markvoldirty(pmp, 1);
341 			if (error)
342 				return (error);
343 		}
344 	}
345 	/*
346 	 * Not an update, or updating the name: look up the name
347 	 * and verify that it refers to a sensible disk device.
348 	 */
349 	if (vfs_getopt(mp->mnt_optnew, "from", (void **)&from, NULL))
350 		return (EINVAL);
351 	NDINIT(&ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, from, td);
352 	error = namei(&ndp);
353 	if (error)
354 		return (error);
355 	devvp = ndp.ni_vp;
356 	NDFREE(&ndp, NDF_ONLY_PNBUF);
357 
358 	if (!vn_isdisk(devvp, &error)) {
359 		vput(devvp);
360 		return (error);
361 	}
362 	/*
363 	 * If mount by non-root, then verify that user has necessary
364 	 * permissions on the device.
365 	 */
366 	accmode = VREAD;
367 	if ((mp->mnt_flag & MNT_RDONLY) == 0)
368 		accmode |= VWRITE;
369 	error = VOP_ACCESS(devvp, accmode, td->td_ucred, td);
370 	if (error)
371 		error = priv_check(td, PRIV_VFS_MOUNT_PERM);
372 	if (error) {
373 		vput(devvp);
374 		return (error);
375 	}
376 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
377 		error = mountmsdosfs(devvp, mp);
378 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
379 		pmp = VFSTOMSDOSFS(mp);
380 #endif
381 	} else {
382 		if (devvp != pmp->pm_devvp)
383 			error = EINVAL;	/* XXX needs translation */
384 		else
385 			vput(devvp);
386 	}
387 	if (error) {
388 		vrele(devvp);
389 		return (error);
390 	}
391 
392 	error = update_mp(mp, td);
393 	if (error) {
394 		if ((mp->mnt_flag & MNT_UPDATE) == 0)
395 			msdosfs_unmount(mp, MNT_FORCE, td);
396 		return error;
397 	}
398 
399 	vfs_mountedfrom(mp, from);
400 #ifdef MSDOSFS_DEBUG
401 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
402 #endif
403 	return (0);
404 }
405 
406 static int
407 mountmsdosfs(struct vnode *devvp, struct mount *mp)
408 {
409 	struct msdosfsmount *pmp;
410 	struct buf *bp;
411 	struct cdev *dev = devvp->v_rdev;
412 	union bootsector *bsp;
413 	struct byte_bpb33 *b33;
414 	struct byte_bpb50 *b50;
415 	struct byte_bpb710 *b710;
416 	u_int8_t SecPerClust;
417 	u_long clusters;
418 	int ronly, error;
419 	struct g_consumer *cp;
420 	struct bufobj *bo;
421 
422 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
423 	/* XXX: use VOP_ACCESS to check FS perms */
424 	DROP_GIANT();
425 	g_topology_lock();
426 	error = g_vfs_open(devvp, &cp, "msdosfs", ronly ? 0 : 1);
427 	g_topology_unlock();
428 	PICKUP_GIANT();
429 	VOP_UNLOCK(devvp, 0);
430 	if (error)
431 		return (error);
432 
433 	bo = &devvp->v_bufobj;
434 	bp = NULL;		/* This and pmp both used in error_exit. */
435 	pmp = NULL;
436 
437 	/*
438 	 * Read the boot sector of the filesystem, and then check the
439 	 * boot signature.  If not a dos boot sector then error out.
440 	 *
441 	 * NOTE: 8192 is a magic size that works for ffs.
442 	 */
443 	error = bread(devvp, 0, 8192, NOCRED, &bp);
444 	if (error)
445 		goto error_exit;
446 	bp->b_flags |= B_AGE;
447 	bsp = (union bootsector *)bp->b_data;
448 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
449 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
450 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
451 
452 #ifndef MSDOSFS_NOCHECKSIG
453 	if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
454 	    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
455 		error = EINVAL;
456 		goto error_exit;
457 	}
458 #endif
459 
460 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
461 	pmp->pm_mountp = mp;
462 	pmp->pm_cp = cp;
463 	pmp->pm_bo = bo;
464 
465 	/*
466 	 * Initialize ownerships and permissions, since nothing else will
467 	 * initialize them iff we are mounting root.
468 	 */
469 	pmp->pm_uid = UID_ROOT;
470 	pmp->pm_gid = GID_WHEEL;
471 	pmp->pm_mask = pmp->pm_dirmask = S_IXUSR | S_IXGRP | S_IXOTH |
472 	    S_IRUSR | S_IRGRP | S_IROTH | S_IWUSR;
473 
474 	/*
475 	 * Experimental support for large MS-DOS filesystems.
476 	 * WARNING: This uses at least 32 bytes of kernel memory (which is not
477 	 * reclaimed until the FS is unmounted) for each file on disk to map
478 	 * between the 32-bit inode numbers used by VFS and the 64-bit
479 	 * pseudo-inode numbers used internally by msdosfs. This is only
480 	 * safe to use in certain controlled situations (e.g. read-only FS
481 	 * with less than 1 million files).
482 	 * Since the mappings do not persist across unmounts (or reboots), these
483 	 * filesystems are not suitable for exporting through NFS, or any other
484 	 * application that requires fixed inode numbers.
485 	 */
486 	vfs_flagopt(mp->mnt_optnew, "large", &pmp->pm_flags, MSDOSFS_LARGEFS);
487 
488 	/*
489 	 * Compute several useful quantities from the bpb in the
490 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
491 	 * the fields that are different between dos 5 and dos 3.3.
492 	 */
493 	SecPerClust = b50->bpbSecPerClust;
494 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
495 	if (pmp->pm_BytesPerSec < DEV_BSIZE) {
496 		error = EINVAL;
497 		goto error_exit;
498 	}
499 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
500 	pmp->pm_FATs = b50->bpbFATs;
501 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
502 	pmp->pm_Sectors = getushort(b50->bpbSectors);
503 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
504 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
505 	pmp->pm_Heads = getushort(b50->bpbHeads);
506 	pmp->pm_Media = b50->bpbMedia;
507 
508 	/* calculate the ratio of sector size to DEV_BSIZE */
509 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
510 
511 	/*
512 	 * We don't check pm_Heads nor pm_SecPerTrack, because
513 	 * these may not be set for EFI file systems. We don't
514 	 * use these anyway, so we're unaffected if they are
515 	 * invalid.
516 	 */
517 	if (!pmp->pm_BytesPerSec || !SecPerClust) {
518 		error = EINVAL;
519 		goto error_exit;
520 	}
521 
522 	if (pmp->pm_Sectors == 0) {
523 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
524 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
525 	} else {
526 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
527 		pmp->pm_HugeSectors = pmp->pm_Sectors;
528 	}
529 	if (!(pmp->pm_flags & MSDOSFS_LARGEFS)) {
530 		if (pmp->pm_HugeSectors > 0xffffffff /
531 		    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
532 			/*
533 			 * We cannot deal currently with this size of disk
534 			 * due to fileid limitations (see msdosfs_getattr and
535 			 * msdosfs_readdir)
536 			 */
537 			error = EINVAL;
538 			vfs_mount_error(mp,
539 			    "Disk too big, try '-o large' mount option");
540 			goto error_exit;
541 		}
542 	}
543 
544 	if (pmp->pm_RootDirEnts == 0) {
545 		if (pmp->pm_Sectors
546 		    || pmp->pm_FATsecs
547 		    || getushort(b710->bpbFSVers)) {
548 			error = EINVAL;
549 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
550 			goto error_exit;
551 		}
552 		pmp->pm_fatmask = FAT32_MASK;
553 		pmp->pm_fatmult = 4;
554 		pmp->pm_fatdiv = 1;
555 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
556 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
557 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
558 		else
559 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
560 	} else
561 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
562 
563 	/*
564 	 * Check a few values (could do some more):
565 	 * - logical sector size: power of 2, >= block size
566 	 * - sectors per cluster: power of 2, >= 1
567 	 * - number of sectors:   >= 1, <= size of partition
568 	 * - number of FAT sectors: >= 1
569 	 */
570 	if ( (SecPerClust == 0)
571 	  || (SecPerClust & (SecPerClust - 1))
572 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
573 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
574 	  || (pmp->pm_HugeSectors == 0)
575 	  || (pmp->pm_FATsecs == 0)
576 	) {
577 		error = EINVAL;
578 		goto error_exit;
579 	}
580 
581 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
582 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec;	/* XXX not used? */
583 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
584 	SecPerClust         *= pmp->pm_BlkPerSec;
585 
586 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
587 
588 	if (FAT32(pmp)) {
589 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
590 		pmp->pm_firstcluster = pmp->pm_fatblk
591 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
592 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
593 	} else {
594 		pmp->pm_rootdirblk = pmp->pm_fatblk +
595 			(pmp->pm_FATs * pmp->pm_FATsecs);
596 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
597 				       + DEV_BSIZE - 1)
598 			/ DEV_BSIZE; /* in blocks */
599 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
600 	}
601 
602 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
603 	    SecPerClust + 1;
604 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE;	/* XXX not used? */
605 
606 	if (pmp->pm_fatmask == 0) {
607 		if (pmp->pm_maxcluster
608 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
609 			/*
610 			 * This will usually be a floppy disk. This size makes
611 			 * sure that one fat entry will not be split across
612 			 * multiple blocks.
613 			 */
614 			pmp->pm_fatmask = FAT12_MASK;
615 			pmp->pm_fatmult = 3;
616 			pmp->pm_fatdiv = 2;
617 		} else {
618 			pmp->pm_fatmask = FAT16_MASK;
619 			pmp->pm_fatmult = 2;
620 			pmp->pm_fatdiv = 1;
621 		}
622 	}
623 
624 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
625 	if (pmp->pm_maxcluster >= clusters) {
626 		printf("Warning: number of clusters (%ld) exceeds FAT "
627 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
628 		pmp->pm_maxcluster = clusters - 1;
629 	}
630 
631 	if (FAT12(pmp))
632 		pmp->pm_fatblocksize = 3 * 512;
633 	else
634 		pmp->pm_fatblocksize = PAGE_SIZE;
635 	pmp->pm_fatblocksize = roundup(pmp->pm_fatblocksize,
636 	    pmp->pm_BytesPerSec);
637 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
638 	pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
639 
640 	/*
641 	 * Compute mask and shift value for isolating cluster relative byte
642 	 * offsets and cluster numbers from a file offset.
643 	 */
644 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
645 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
646 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
647 
648 	/*
649 	 * Check for valid cluster size
650 	 * must be a power of 2
651 	 */
652 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
653 		error = EINVAL;
654 		goto error_exit;
655 	}
656 
657 	/*
658 	 * Release the bootsector buffer.
659 	 */
660 	brelse(bp);
661 	bp = NULL;
662 
663 	/*
664 	 * Check the fsinfo sector if we have one.  Silently fix up our
665 	 * in-core copy of fp->fsinxtfree if it is unknown (0xffffffff)
666 	 * or too large.  Ignore fp->fsinfree for now, since we need to
667 	 * read the entire FAT anyway to fill the inuse map.
668 	 */
669 	if (pmp->pm_fsinfo) {
670 		struct fsinfo *fp;
671 
672 		if ((error = bread(devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
673 		    NOCRED, &bp)) != 0)
674 			goto error_exit;
675 		fp = (struct fsinfo *)bp->b_data;
676 		if (!bcmp(fp->fsisig1, "RRaA", 4)
677 		    && !bcmp(fp->fsisig2, "rrAa", 4)
678 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)) {
679 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
680 			if (pmp->pm_nxtfree > pmp->pm_maxcluster)
681 				pmp->pm_nxtfree = CLUST_FIRST;
682 		} else
683 			pmp->pm_fsinfo = 0;
684 		brelse(bp);
685 		bp = NULL;
686 	}
687 
688 	/*
689 	 * Finish initializing pmp->pm_nxtfree (just in case the first few
690 	 * sectors aren't properly reserved in the FAT).  This completes
691 	 * the fixup for fp->fsinxtfree, and fixes up the zero-initialized
692 	 * value if there is no fsinfo.  We will use pmp->pm_nxtfree
693 	 * internally even if there is no fsinfo.
694 	 */
695 	if (pmp->pm_nxtfree < CLUST_FIRST)
696 		pmp->pm_nxtfree = CLUST_FIRST;
697 
698 	/*
699 	 * Allocate memory for the bitmap of allocated clusters, and then
700 	 * fill it in.
701 	 */
702 	pmp->pm_inusemap = malloc(howmany(pmp->pm_maxcluster + 1, N_INUSEBITS)
703 				  * sizeof(*pmp->pm_inusemap),
704 				  M_MSDOSFSFAT, M_WAITOK);
705 
706 	/*
707 	 * fillinusemap() needs pm_devvp.
708 	 */
709 	pmp->pm_devvp = devvp;
710 
711 	/*
712 	 * Have the inuse map filled in.
713 	 */
714 	if ((error = fillinusemap(pmp)) != 0)
715 		goto error_exit;
716 
717 	/*
718 	 * If they want fat updates to be synchronous then let them suffer
719 	 * the performance degradation in exchange for the on disk copy of
720 	 * the fat being correct just about all the time.  I suppose this
721 	 * would be a good thing to turn on if the kernel is still flakey.
722 	 */
723 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
724 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
725 
726 	/*
727 	 * Finish up.
728 	 */
729 	if (ronly)
730 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
731 	else {
732 		if ((error = markvoldirty(pmp, 1)) != 0) {
733 			(void)markvoldirty(pmp, 0);
734 			goto error_exit;
735 		}
736 		pmp->pm_fmod = 1;
737 	}
738 	mp->mnt_data =  pmp;
739 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
740 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
741 	MNT_ILOCK(mp);
742 	mp->mnt_flag |= MNT_LOCAL;
743 	MNT_IUNLOCK(mp);
744 
745 	if (pmp->pm_flags & MSDOSFS_LARGEFS)
746 		msdosfs_fileno_init(mp);
747 
748 	return 0;
749 
750 error_exit:
751 	if (bp)
752 		brelse(bp);
753 	if (cp != NULL) {
754 		DROP_GIANT();
755 		g_topology_lock();
756 		g_vfs_close(cp);
757 		g_topology_unlock();
758 		PICKUP_GIANT();
759 	}
760 	if (pmp) {
761 		if (pmp->pm_inusemap)
762 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
763 		free(pmp, M_MSDOSFSMNT);
764 		mp->mnt_data = NULL;
765 	}
766 	return (error);
767 }
768 
769 /*
770  * Unmount the filesystem described by mp.
771  */
772 static int
773 msdosfs_unmount(struct mount *mp, int mntflags, struct thread *td)
774 {
775 	struct msdosfsmount *pmp;
776 	int error, flags;
777 
778 	flags = 0;
779 	if (mntflags & MNT_FORCE)
780 		flags |= FORCECLOSE;
781 	error = vflush(mp, 0, flags, td);
782 	if (error)
783 		return error;
784 	pmp = VFSTOMSDOSFS(mp);
785 	if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) {
786 		error = markvoldirty(pmp, 0);
787 		if (error) {
788 			(void)markvoldirty(pmp, 1);
789 			return (error);
790 		}
791 	}
792 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
793 		if (pmp->pm_w2u)
794 			msdosfs_iconv->close(pmp->pm_w2u);
795 		if (pmp->pm_u2w)
796 			msdosfs_iconv->close(pmp->pm_u2w);
797 		if (pmp->pm_d2u)
798 			msdosfs_iconv->close(pmp->pm_d2u);
799 		if (pmp->pm_u2d)
800 			msdosfs_iconv->close(pmp->pm_u2d);
801 	}
802 
803 #ifdef MSDOSFS_DEBUG
804 	{
805 		struct vnode *vp = pmp->pm_devvp;
806 		struct bufobj *bo;
807 
808 		bo = &vp->v_bufobj;
809 		BO_LOCK(bo);
810 		VI_LOCK(vp);
811 		vn_printf(vp,
812 		    "msdosfs_umount(): just before calling VOP_CLOSE()\n");
813 		printf("freef %p, freeb %p, mount %p\n",
814 		    TAILQ_NEXT(vp, v_freelist), vp->v_freelist.tqe_prev,
815 		    vp->v_mount);
816 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
817 		    TAILQ_FIRST(&vp->v_bufobj.bo_clean.bv_hd),
818 		    TAILQ_FIRST(&vp->v_bufobj.bo_dirty.bv_hd),
819 		    vp->v_bufobj.bo_numoutput, vp->v_type);
820 		VI_UNLOCK(vp);
821 		BO_UNLOCK(bo);
822 	}
823 #endif
824 	DROP_GIANT();
825 	g_topology_lock();
826 	g_vfs_close(pmp->pm_cp);
827 	g_topology_unlock();
828 	PICKUP_GIANT();
829 	vrele(pmp->pm_devvp);
830 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
831 	if (pmp->pm_flags & MSDOSFS_LARGEFS)
832 		msdosfs_fileno_free(mp);
833 	free(pmp, M_MSDOSFSMNT);
834 	mp->mnt_data = NULL;
835 	MNT_ILOCK(mp);
836 	mp->mnt_flag &= ~MNT_LOCAL;
837 	MNT_IUNLOCK(mp);
838 	return (0);
839 }
840 
841 static int
842 msdosfs_root(struct mount *mp, int flags, struct vnode **vpp, struct thread *td)
843 {
844 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
845 	struct denode *ndep;
846 	int error;
847 
848 #ifdef MSDOSFS_DEBUG
849 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
850 #endif
851 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
852 	if (error)
853 		return (error);
854 	*vpp = DETOV(ndep);
855 	return (0);
856 }
857 
858 static int
859 msdosfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
860 {
861 	struct msdosfsmount *pmp;
862 
863 	pmp = VFSTOMSDOSFS(mp);
864 	sbp->f_bsize = pmp->pm_bpcluster;
865 	sbp->f_iosize = pmp->pm_bpcluster;
866 	sbp->f_blocks = pmp->pm_maxcluster + 1;
867 	sbp->f_bfree = pmp->pm_freeclustercount;
868 	sbp->f_bavail = pmp->pm_freeclustercount;
869 	sbp->f_files = pmp->pm_RootDirEnts;	/* XXX */
870 	sbp->f_ffree = 0;	/* what to put in here? */
871 	return (0);
872 }
873 
874 static int
875 msdosfs_sync(struct mount *mp, int waitfor, struct thread *td)
876 {
877 	struct vnode *vp, *nvp;
878 	struct denode *dep;
879 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
880 	int error, allerror = 0;
881 
882 	/*
883 	 * If we ever switch to not updating all of the fats all the time,
884 	 * this would be the place to update them from the first one.
885 	 */
886 	if (pmp->pm_fmod != 0) {
887 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
888 			panic("msdosfs_sync: rofs mod");
889 		else {
890 			/* update fats here */
891 		}
892 	}
893 	/*
894 	 * Write back each (modified) denode.
895 	 */
896 	MNT_ILOCK(mp);
897 loop:
898 	MNT_VNODE_FOREACH(vp, mp, nvp) {
899 		VI_LOCK(vp);
900 		if (vp->v_type == VNON || (vp->v_iflag & VI_DOOMED)) {
901 			VI_UNLOCK(vp);
902 			continue;
903 		}
904 		MNT_IUNLOCK(mp);
905 		dep = VTODE(vp);
906 		if ((dep->de_flag &
907 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
908 		    (vp->v_bufobj.bo_dirty.bv_cnt == 0 ||
909 		    waitfor == MNT_LAZY)) {
910 			VI_UNLOCK(vp);
911 			MNT_ILOCK(mp);
912 			continue;
913 		}
914 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, td);
915 		if (error) {
916 			MNT_ILOCK(mp);
917 			if (error == ENOENT)
918 				goto loop;
919 			continue;
920 		}
921 		error = VOP_FSYNC(vp, waitfor, td);
922 		if (error)
923 			allerror = error;
924 		VOP_UNLOCK(vp, 0);
925 		vrele(vp);
926 		MNT_ILOCK(mp);
927 	}
928 	MNT_IUNLOCK(mp);
929 
930 	/*
931 	 * Flush filesystem control info.
932 	 */
933 	if (waitfor != MNT_LAZY) {
934 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
935 		error = VOP_FSYNC(pmp->pm_devvp, waitfor, td);
936 		if (error)
937 			allerror = error;
938 		VOP_UNLOCK(pmp->pm_devvp, 0);
939 	}
940 	return (allerror);
941 }
942 
943 static int
944 msdosfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
945 {
946 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
947 	struct defid *defhp = (struct defid *) fhp;
948 	struct denode *dep;
949 	int error;
950 
951 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
952 	if (error) {
953 		*vpp = NULLVP;
954 		return (error);
955 	}
956 	*vpp = DETOV(dep);
957 	vnode_create_vobject(*vpp, dep->de_FileSize, curthread);
958 	return (0);
959 }
960 
961 static struct vfsops msdosfs_vfsops = {
962 	.vfs_fhtovp =		msdosfs_fhtovp,
963 	.vfs_mount =		msdosfs_mount,
964 	.vfs_cmount =		msdosfs_cmount,
965 	.vfs_root =		msdosfs_root,
966 	.vfs_statfs =		msdosfs_statfs,
967 	.vfs_sync =		msdosfs_sync,
968 	.vfs_unmount =		msdosfs_unmount,
969 };
970 
971 VFS_SET(msdosfs_vfsops, msdosfs, 0);
972 MODULE_VERSION(msdosfs, 1);
973