xref: /freebsd/sys/fs/msdosfs/msdosfs_vfsops.c (revision a35d88931c87cfe6bd38f01d7bad22140b3b38f3)
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 "opt_msdosfs.h"
75 
76 #define MSDOSFS_DFLTBSIZE       4096
77 
78 #if 1 /*def PC98*/
79 /*
80  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
81  *       garbage or a random value :-{
82  *       If you want to use that broken-signatured media, define the
83  *       following symbol even though PC/AT.
84  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
85  */
86 #define	MSDOSFS_NOCHECKSIG
87 #endif
88 
89 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOSFS mount structure");
90 static MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOSFS file allocation table");
91 
92 struct iconv_functions *msdosfs_iconv = NULL;
93 
94 static int	update_mp(struct mount *mp, struct msdosfs_args *argp,
95 		    struct thread *td);
96 static int	mountmsdosfs(struct vnode *devvp, struct mount *mp,
97 		    struct thread *td, struct msdosfs_args *argp);
98 static vfs_fhtovp_t	msdosfs_fhtovp;
99 static vfs_omount_t	msdosfs_omount;
100 static vfs_root_t	msdosfs_root;
101 static vfs_statfs_t	msdosfs_statfs;
102 static vfs_sync_t	msdosfs_sync;
103 static vfs_unmount_t	msdosfs_unmount;
104 static vfs_vptofh_t	msdosfs_vptofh;
105 
106 /* Maximum length of a character set name (arbitrary). */
107 #define	MAXCSLEN	64
108 
109 static int
110 update_mp(mp, argp, td)
111 	struct mount *mp;
112 	struct msdosfs_args *argp;
113 	struct thread *td;
114 {
115 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
116 	char *dos, *win, *local;
117 	int error;
118 
119 	if (argp->flags & MSDOSFSMNT_KICONV) {
120 		if (msdosfs_iconv) {
121 			win = malloc(MAXCSLEN, M_TEMP, M_WAITOK);
122 			local = malloc(MAXCSLEN, M_TEMP, M_WAITOK);
123 			dos = malloc(MAXCSLEN, M_TEMP, M_WAITOK);
124 			if ((error = copyinstr(argp->cs_win, win, MAXCSLEN,
125 			    NULL)) != 0)
126 				goto iconvdone;
127 			if ((error = copyinstr(argp->cs_local, local, MAXCSLEN,
128 			    NULL)) != 0)
129 				goto iconvdone;
130 			if ((error = copyinstr(argp->cs_dos, dos, MAXCSLEN,
131 			    NULL)) != 0)
132 				goto iconvdone;
133 			msdosfs_iconv->open(win, local, &pmp->pm_u2w);
134 			msdosfs_iconv->open(local, win, &pmp->pm_w2u);
135 			msdosfs_iconv->open(dos, local, &pmp->pm_u2d);
136 			msdosfs_iconv->open(local, dos, &pmp->pm_d2u);
137 iconvdone:		free(win, M_TEMP);
138 			free(local, M_TEMP);
139 			free(dos, M_TEMP);
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 	pmp->pm_gid = argp->gid;
151 	pmp->pm_uid = argp->uid;
152 	pmp->pm_mask = argp->mask & ALLPERMS;
153 	pmp->pm_dirmask = argp->dirmask & ALLPERMS;
154 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
155 
156 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
157 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
158 	else if (!(pmp->pm_flags &
159 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
160 		struct vnode *rootvp;
161 
162 		/*
163 		 * Try to divine whether to support Win'95 long filenames
164 		 */
165 		if (FAT32(pmp))
166 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
167 		else {
168 			if ((error = msdosfs_root(mp, &rootvp, td)) != 0)
169 				return error;
170 			pmp->pm_flags |= findwin95(VTODE(rootvp))
171 				? MSDOSFSMNT_LONGNAME
172 					: MSDOSFSMNT_SHORTNAME;
173 			vput(rootvp);
174 		}
175 	}
176 	return 0;
177 }
178 
179 /*
180  * mp - path - addr in user space of mount point (ie /usr or whatever)
181  * data - addr in user space of mount params including the name of the block
182  * special file to treat as a filesystem.
183  */
184 static int
185 msdosfs_omount(mp, path, data, td)
186 	struct mount *mp;
187 	char *path;
188 	caddr_t data;
189 	struct thread *td;
190 {
191 	struct vnode *devvp;	  /* vnode for blk device to mount */
192 	struct msdosfs_args args; /* will hold data from mount request */
193 	/* msdosfs specific mount control block */
194 	struct msdosfsmount *pmp = NULL;
195 	struct nameidata ndp;
196 	size_t size;
197 	int error, flags;
198 	mode_t accessmode;
199 
200 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
201 	if (error)
202 		return (error);
203 	if (args.magic != MSDOSFS_ARGSMAGIC)
204 		args.flags = 0;
205 	/*
206 	 * If updating, check whether changing from read-only to
207 	 * read/write; if there is no device name, that's all we do.
208 	 */
209 	if (mp->mnt_flag & MNT_UPDATE) {
210 		pmp = VFSTOMSDOSFS(mp);
211 		error = 0;
212 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
213 			error = VFS_SYNC(mp, MNT_WAIT, td->td_ucred, td);
214 			if (error)
215 				return (error);
216 			flags = WRITECLOSE;
217 			if (mp->mnt_flag & MNT_FORCE)
218 				flags |= FORCECLOSE;
219 			error = vflush(mp, 0, flags, td);
220 		}
221 		if (!error && (mp->mnt_flag & MNT_RELOAD))
222 			/* not yet implemented */
223 			error = EOPNOTSUPP;
224 		if (error)
225 			return (error);
226 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
227 			/*
228 			 * If upgrade to read-write by non-root, then verify
229 			 * that user has necessary permissions on the device.
230 			 */
231 			if (suser(td)) {
232 				devvp = pmp->pm_devvp;
233 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
234 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
235 						   td->td_ucred, td);
236 				if (error) {
237 					VOP_UNLOCK(devvp, 0, td);
238 					return (error);
239 				}
240 				VOP_UNLOCK(devvp, 0, td);
241 			}
242 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
243 
244 			/* Now that the volume is modifiable, mark it dirty. */
245 			error = markvoldirty(pmp, 1);
246 			if (error)
247 				return (error);
248 		}
249 		if (args.fspec == 0) {
250 #ifdef	__notyet__	/* doesn't work correctly with current mountd	XXX */
251 			if (args.flags & MSDOSFSMNT_MNTOPT) {
252 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
253 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
254 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
255 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
256 			}
257 #endif
258 			/*
259 			 * Process export requests.
260 			 */
261 			if ((args.export.ex_flags & MNT_EXPORTED) != 0 &&
262 			    (pmp->pm_flags & MSDOSFS_LARGEFS) != 0)
263 				return (EOPNOTSUPP);
264 			return (vfs_export(mp, &args.export));
265 		}
266 	}
267 	/*
268 	 * Not an update, or updating the name: look up the name
269 	 * and verify that it refers to a sensible disk device.
270 	 */
271 	NDINIT(&ndp, LOOKUP, FOLLOW, UIO_USERSPACE, args.fspec, td);
272 	error = namei(&ndp);
273 	if (error)
274 		return (error);
275 	devvp = ndp.ni_vp;
276 	NDFREE(&ndp, NDF_ONLY_PNBUF);
277 
278 	if (!vn_isdisk(devvp, &error)) {
279 		vrele(devvp);
280 		return (error);
281 	}
282 	/*
283 	 * If mount by non-root, then verify that user has necessary
284 	 * permissions on the device.
285 	 */
286 	if (suser(td)) {
287 		accessmode = VREAD;
288 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
289 			accessmode |= VWRITE;
290 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
291 		error = VOP_ACCESS(devvp, accessmode, td->td_ucred, td);
292 		if (error) {
293 			vput(devvp);
294 			return (error);
295 		}
296 		VOP_UNLOCK(devvp, 0, td);
297 	}
298 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
299 		error = mountmsdosfs(devvp, mp, td, &args);
300 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
301 		pmp = VFSTOMSDOSFS(mp);
302 #endif
303 	} else {
304 		if (devvp != pmp->pm_devvp)
305 			error = EINVAL;	/* XXX needs translation */
306 		else
307 			vrele(devvp);
308 	}
309 	if (error) {
310 		vrele(devvp);
311 		return (error);
312 	}
313 
314 	error = update_mp(mp, &args, td);
315 	if (error) {
316 		if ((mp->mnt_flag & MNT_UPDATE) == 0)
317 			msdosfs_unmount(mp, MNT_FORCE, td);
318 		return error;
319 	}
320 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
321 	    &size);
322 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
323 	(void) msdosfs_statfs(mp, &mp->mnt_stat, td);
324 #ifdef MSDOSFS_DEBUG
325 	printf("msdosfs_omount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
326 #endif
327 	return (0);
328 }
329 
330 static int
331 mountmsdosfs(devvp, mp, td, argp)
332 	struct vnode *devvp;
333 	struct mount *mp;
334 	struct thread *td;
335 	struct msdosfs_args *argp;
336 {
337 	struct msdosfsmount *pmp;
338 	struct buf *bp;
339 	struct cdev *dev = devvp->v_rdev;
340 	union bootsector *bsp;
341 	struct byte_bpb33 *b33;
342 	struct byte_bpb50 *b50;
343 	struct byte_bpb710 *b710;
344 	u_int8_t SecPerClust;
345 	u_long clusters;
346 	int	ronly, error;
347 
348 	/*
349 	 * Disallow multiple mounts of the same device.
350 	 * Disallow mounting of a device that is currently in use
351 	 * (except for root, which might share swap device for miniroot).
352 	 * Flush out any old buffers remaining from a previous use.
353 	 */
354 	error = vfs_mountedon(devvp);
355 	if (error)
356 		return (error);
357 	if (vcount(devvp) > 1)
358 		return (EBUSY);
359 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
360 	error = vinvalbuf(devvp, V_SAVE, td->td_ucred, td, 0, 0);
361 	if (error) {
362 		VOP_UNLOCK(devvp, 0, td);
363 		return (error);
364 	}
365 
366 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
367 	/*
368 	 * XXX: open the device with read and write access even if only
369 	 * read access is needed now.  Write access is needed if the
370 	 * filesystem is ever mounted read/write, and we don't change the
371 	 * access mode for remounts.
372 	 */
373 #ifdef notyet
374 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD | FWRITE, FSCRED, td, -1);
375 #else
376 	error = VOP_OPEN(devvp, FREAD | FWRITE, FSCRED, td, -1);
377 #endif
378 	VOP_UNLOCK(devvp, 0, td);
379 	if (error)
380 		return (error);
381 
382 	bp  = NULL; /* both used in error_exit */
383 	pmp = NULL;
384 
385 	/*
386 	 * Read the boot sector of the filesystem, and then check the
387 	 * boot signature.  If not a dos boot sector then error out.
388 	 *
389 	 * NOTE: 2048 is a maximum sector size in current...
390 	 */
391 	error = bread(devvp, 0, 2048, NOCRED, &bp);
392 	if (error)
393 		goto error_exit;
394 	bp->b_flags |= B_AGE;
395 	bsp = (union bootsector *)bp->b_data;
396 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
397 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
398 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
399 
400 #ifndef MSDOSFS_NOCHECKSIG
401 	if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
402 	    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
403 		error = EINVAL;
404 		goto error_exit;
405 	}
406 #endif
407 
408 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
409 	pmp->pm_mountp = mp;
410 
411 	/*
412 	 * Compute several useful quantities from the bpb in the
413 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
414 	 * the fields that are different between dos 5 and dos 3.3.
415 	 */
416 	SecPerClust = b50->bpbSecPerClust;
417 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
418 	if (pmp->pm_BytesPerSec < DEV_BSIZE) {
419 		error = EINVAL;
420 		goto error_exit;
421 	}
422 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
423 	pmp->pm_FATs = b50->bpbFATs;
424 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
425 	pmp->pm_Sectors = getushort(b50->bpbSectors);
426 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
427 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
428 	pmp->pm_Heads = getushort(b50->bpbHeads);
429 	pmp->pm_Media = b50->bpbMedia;
430 
431 	/* calculate the ratio of sector size to DEV_BSIZE */
432 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
433 
434 	/* XXX - We should probably check more values here */
435 	if (!pmp->pm_BytesPerSec || !SecPerClust
436 		|| !pmp->pm_Heads
437 #ifdef PC98
438     		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) {
439 #else
440 		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
441 #endif
442 		error = EINVAL;
443 		goto error_exit;
444 	}
445 
446 	if (pmp->pm_Sectors == 0) {
447 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
448 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
449 	} else {
450 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
451 		pmp->pm_HugeSectors = pmp->pm_Sectors;
452 	}
453 #ifndef MSDOSFS_LARGE
454 	if (pmp->pm_HugeSectors > 0xffffffff /
455 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
456 		/*
457 		 * We cannot deal currently with this size of disk
458 		 * due to fileid limitations (see msdosfs_getattr and
459 		 * msdosfs_readdir)
460 		 */
461 		error = EINVAL;
462 		printf("mountmsdosfs(): disk too big, sorry\n");
463 		goto error_exit;
464 	}
465 #endif	/* !MSDOSFS_LARGE */
466 
467 	if (pmp->pm_RootDirEnts == 0) {
468 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
469 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
470 		    || pmp->pm_Sectors
471 		    || pmp->pm_FATsecs
472 		    || getushort(b710->bpbFSVers)) {
473 			error = EINVAL;
474 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
475 			goto error_exit;
476 		}
477 		pmp->pm_fatmask = FAT32_MASK;
478 		pmp->pm_fatmult = 4;
479 		pmp->pm_fatdiv = 1;
480 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
481 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
482 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
483 		else
484 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
485 	} else
486 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
487 
488 	/*
489 	 * Check a few values (could do some more):
490 	 * - logical sector size: power of 2, >= block size
491 	 * - sectors per cluster: power of 2, >= 1
492 	 * - number of sectors:   >= 1, <= size of partition
493 	 * - number of FAT sectors: >= 1
494 	 */
495 	if ( (SecPerClust == 0)
496 	  || (SecPerClust & (SecPerClust - 1))
497 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
498 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
499 	  || (pmp->pm_HugeSectors == 0)
500 	  || (pmp->pm_FATsecs == 0)
501 	) {
502 		error = EINVAL;
503 		goto error_exit;
504 	}
505 
506 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
507 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
508 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
509 	SecPerClust         *= pmp->pm_BlkPerSec;
510 
511 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
512 
513 	if (FAT32(pmp)) {
514 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
515 		pmp->pm_firstcluster = pmp->pm_fatblk
516 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
517 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
518 	} else {
519 		pmp->pm_rootdirblk = pmp->pm_fatblk +
520 			(pmp->pm_FATs * pmp->pm_FATsecs);
521 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
522 				       + DEV_BSIZE - 1)
523 			/ DEV_BSIZE; /* in blocks */
524 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
525 	}
526 
527 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
528 	    SecPerClust + 1;
529 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
530 
531 	if (pmp->pm_fatmask == 0) {
532 		if (pmp->pm_maxcluster
533 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
534 			/*
535 			 * This will usually be a floppy disk. This size makes
536 			 * sure that one fat entry will not be split across
537 			 * multiple blocks.
538 			 */
539 			pmp->pm_fatmask = FAT12_MASK;
540 			pmp->pm_fatmult = 3;
541 			pmp->pm_fatdiv = 2;
542 		} else {
543 			pmp->pm_fatmask = FAT16_MASK;
544 			pmp->pm_fatmult = 2;
545 			pmp->pm_fatdiv = 1;
546 		}
547 	}
548 
549 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
550 	if (pmp->pm_maxcluster >= clusters) {
551 		printf("Warning: number of clusters (%ld) exceeds FAT "
552 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
553 		pmp->pm_maxcluster = clusters - 1;
554 	}
555 
556 
557 	if (FAT12(pmp))
558 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
559 	else
560 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
561 
562 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
563 	pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
564 
565 	/*
566 	 * Compute mask and shift value for isolating cluster relative byte
567 	 * offsets and cluster numbers from a file offset.
568 	 */
569 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
570 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
571 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
572 
573 	/*
574 	 * Check for valid cluster size
575 	 * must be a power of 2
576 	 */
577 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
578 		error = EINVAL;
579 		goto error_exit;
580 	}
581 
582 	/*
583 	 * Release the bootsector buffer.
584 	 */
585 	brelse(bp);
586 	bp = NULL;
587 
588 	/*
589 	 * Check FSInfo.
590 	 */
591 	if (pmp->pm_fsinfo) {
592 		struct fsinfo *fp;
593 
594 		if ((error = bread(devvp, pmp->pm_fsinfo, fsi_size(pmp),
595 		    NOCRED, &bp)) != 0)
596 			goto error_exit;
597 		fp = (struct fsinfo *)bp->b_data;
598 		if (!bcmp(fp->fsisig1, "RRaA", 4)
599 		    && !bcmp(fp->fsisig2, "rrAa", 4)
600 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
601 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4)) {
602 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
603 			if (pmp->pm_nxtfree == 0xffffffff)
604 				pmp->pm_nxtfree = CLUST_FIRST;
605 		} else
606 			pmp->pm_fsinfo = 0;
607 		brelse(bp);
608 		bp = NULL;
609 	}
610 
611 	/*
612 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
613 	 */
614 	if (pmp->pm_fsinfo && pmp->pm_nxtfree > pmp->pm_maxcluster) {
615 		printf(
616 		"Next free cluster in FSInfo (%lu) exceeds maxcluster (%lu)\n",
617 		    pmp->pm_nxtfree, pmp->pm_maxcluster);
618 		error = EINVAL;
619 		goto error_exit;
620 	}
621 
622 	/*
623 	 * Allocate memory for the bitmap of allocated clusters, and then
624 	 * fill it in.
625 	 */
626 	pmp->pm_inusemap = malloc(howmany(pmp->pm_maxcluster + 1, N_INUSEBITS)
627 				  * sizeof(*pmp->pm_inusemap),
628 				  M_MSDOSFSFAT, M_WAITOK);
629 
630 	/*
631 	 * fillinusemap() needs pm_devvp.
632 	 */
633 	pmp->pm_dev = dev;
634 	pmp->pm_devvp = devvp;
635 
636 	/*
637 	 * Have the inuse map filled in.
638 	 */
639 	if ((error = fillinusemap(pmp)) != 0)
640 		goto error_exit;
641 
642 	/*
643 	 * If they want fat updates to be synchronous then let them suffer
644 	 * the performance degradation in exchange for the on disk copy of
645 	 * the fat being correct just about all the time.  I suppose this
646 	 * would be a good thing to turn on if the kernel is still flakey.
647 	 */
648 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
649 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
650 
651 	/*
652 	 * Finish up.
653 	 */
654 	if (ronly)
655 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
656 	else {
657 		/* Mark the volume dirty while it is mounted read/write. */
658 		if ((error = markvoldirty(pmp, 1)) != 0)
659 			goto error_exit;
660 		pmp->pm_fmod = 1;
661 	}
662 	mp->mnt_data = (qaddr_t) pmp;
663 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
664 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
665 	mp->mnt_flag |= MNT_LOCAL;
666 	devvp->v_rdev->si_mountpoint = mp;
667 
668 #ifdef MSDOSFS_LARGE
669 	msdosfs_fileno_init(mp);
670 #endif
671 
672 	return 0;
673 
674 error_exit:
675 	if (bp)
676 		brelse(bp);
677 	/* XXX: see comment above VOP_OPEN. */
678 #ifdef notyet
679 	(void)VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE, NOCRED, td);
680 #else
681 	(void)VOP_CLOSE(devvp, FREAD | FWRITE, NOCRED, td);
682 #endif
683 	if (pmp) {
684 		if (pmp->pm_inusemap)
685 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
686 		free(pmp, M_MSDOSFSMNT);
687 		mp->mnt_data = (qaddr_t)0;
688 	}
689 	return (error);
690 }
691 
692 /*
693  * Unmount the filesystem described by mp.
694  */
695 static int
696 msdosfs_unmount(mp, mntflags, td)
697 	struct mount *mp;
698 	int mntflags;
699 	struct thread *td;
700 {
701 	struct msdosfsmount *pmp;
702 	int error, flags;
703 
704 	flags = 0;
705 	if (mntflags & MNT_FORCE)
706 		flags |= FORCECLOSE;
707 	error = vflush(mp, 0, flags, td);
708 	if (error)
709 		return error;
710 	pmp = VFSTOMSDOSFS(mp);
711 	if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
712 		if (pmp->pm_w2u)
713 			msdosfs_iconv->close(pmp->pm_w2u);
714 		if (pmp->pm_u2w)
715 			msdosfs_iconv->close(pmp->pm_u2w);
716 		if (pmp->pm_d2u)
717 			msdosfs_iconv->close(pmp->pm_d2u);
718 		if (pmp->pm_u2d)
719 			msdosfs_iconv->close(pmp->pm_u2d);
720 	}
721 	pmp->pm_devvp->v_rdev->si_mountpoint = NULL;
722 
723 	/* If the volume was mounted read/write, mark it clean now. */
724 	if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) {
725 		error = markvoldirty(pmp, 0);
726 		if (error && (flags & FORCECLOSE) == 0)
727 			return (error);
728 	}
729 #ifdef MSDOSFS_DEBUG
730 	{
731 		struct vnode *vp = pmp->pm_devvp;
732 
733 		VI_LOCK(vp);
734 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
735 		printf("iflag %08lx, usecount %d, writecount %d, holdcnt %ld\n",
736 		    vp->vi_flag, vp->v_usecount, vp->v_writecount,
737 		    vp->v_holdcnt);
738 		printf("id %lu, mount %p, op %p\n",
739 		    vp->v_id, vp->v_mount, vp->v_op);
740 		printf("freef %p, freeb %p, mount %p\n",
741 		    TAILQ_NEXT(vp, v_freelist), vp->v_freelist.tqe_prev,
742 		    vp->v_mount);
743 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
744 		    TAILQ_FIRST(&vp->v_cleanblkhd),
745 		    TAILQ_FIRST(&vp->v_dirtyblkhd),
746 		    vp->v_numoutput, vp->v_type);
747 		printf("union %p, tag %s, data[0] %08x, data[1] %08x\n",
748 		    vp->v_socket, vp->v_tag,
749 		    ((u_int *)vp->v_data)[0],
750 		    ((u_int *)vp->v_data)[1]);
751 		VI_UNLOCK(vp);
752 	}
753 #endif
754 	/* XXX: see comment above VOP_OPEN. */
755 #ifdef notyet
756 	error = VOP_CLOSE(pmp->pm_devvp,
757 	    (pmp->pm_flags & MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE,
758 	    NOCRED, td);
759 #else
760 	error = VOP_CLOSE(pmp->pm_devvp, FREAD | FWRITE, NOCRED, td);
761 #endif
762 	vrele(pmp->pm_devvp);
763 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
764 #ifdef MSDOSFS_LARGE
765 	msdosfs_fileno_free(mp);
766 #endif
767 	free(pmp, M_MSDOSFSMNT);
768 	mp->mnt_data = (qaddr_t)0;
769 	mp->mnt_flag &= ~MNT_LOCAL;
770 	return (error);
771 }
772 
773 static int
774 msdosfs_root(mp, vpp, td)
775 	struct mount *mp;
776 	struct vnode **vpp;
777 	struct thread *td;
778 {
779 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
780 	struct denode *ndep;
781 	int error;
782 
783 #ifdef MSDOSFS_DEBUG
784 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
785 #endif
786 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
787 	if (error)
788 		return (error);
789 	*vpp = DETOV(ndep);
790 	return (0);
791 }
792 
793 static int
794 msdosfs_statfs(mp, sbp, td)
795 	struct mount *mp;
796 	struct statfs *sbp;
797 	struct thread *td;
798 {
799 	struct msdosfsmount *pmp;
800 
801 	pmp = VFSTOMSDOSFS(mp);
802 	sbp->f_bsize = pmp->pm_bpcluster;
803 	sbp->f_iosize = pmp->pm_bpcluster;
804 	sbp->f_blocks = pmp->pm_maxcluster + 1;
805 	sbp->f_bfree = pmp->pm_freeclustercount;
806 	sbp->f_bavail = pmp->pm_freeclustercount;
807 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
808 	sbp->f_ffree = 0;	/* what to put in here? */
809 	if (sbp != &mp->mnt_stat) {
810 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
811 		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
812 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
813 	}
814 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
815 	return (0);
816 }
817 
818 static int
819 msdosfs_sync(mp, waitfor, cred, td)
820 	struct mount *mp;
821 	int waitfor;
822 	struct ucred *cred;
823 	struct thread *td;
824 {
825 	struct vnode *vp, *nvp;
826 	struct denode *dep;
827 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
828 	int error, allerror = 0;
829 
830 	/*
831 	 * If we ever switch to not updating all of the fats all the time,
832 	 * this would be the place to update them from the first one.
833 	 */
834 	if (pmp->pm_fmod != 0) {
835 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
836 			panic("msdosfs_sync: rofs mod");
837 		else {
838 			/* update fats here */
839 		}
840 	}
841 	/*
842 	 * Write back each (modified) denode.
843 	 */
844 	MNT_ILOCK(mp);
845 loop:
846 	MNT_VNODE_FOREACH(vp, mp, nvp) {
847 		VI_LOCK(vp);
848 		if (vp->v_iflag & VI_XLOCK) {
849 			VI_UNLOCK(vp);
850 			continue;
851 		}
852 		MNT_IUNLOCK(mp);
853 		dep = VTODE(vp);
854 		if (vp->v_type == VNON ||
855 		    ((dep->de_flag &
856 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
857 		    (TAILQ_EMPTY(&vp->v_dirtyblkhd) || waitfor == MNT_LAZY))) {
858 			VI_UNLOCK(vp);
859 			MNT_ILOCK(mp);
860 			continue;
861 		}
862 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, td);
863 		if (error) {
864 			MNT_ILOCK(mp);
865 			if (error == ENOENT)
866 				goto loop;
867 			continue;
868 		}
869 		error = VOP_FSYNC(vp, cred, waitfor, td);
870 		if (error)
871 			allerror = error;
872 		VOP_UNLOCK(vp, 0, td);
873 		vrele(vp);
874 		MNT_ILOCK(mp);
875 	}
876 	MNT_IUNLOCK(mp);
877 
878 	/*
879 	 * Flush filesystem control info.
880 	 */
881 	if (waitfor != MNT_LAZY) {
882 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY, td);
883 		error = VOP_FSYNC(pmp->pm_devvp, cred, waitfor, td);
884 		if (error)
885 			allerror = error;
886 		VOP_UNLOCK(pmp->pm_devvp, 0, td);
887 	}
888 	return (allerror);
889 }
890 
891 static int
892 msdosfs_fhtovp(mp, fhp, vpp)
893 	struct mount *mp;
894 	struct fid *fhp;
895 	struct vnode **vpp;
896 {
897 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
898 	struct defid *defhp = (struct defid *) fhp;
899 	struct denode *dep;
900 	int error;
901 
902 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
903 	if (error) {
904 		*vpp = NULLVP;
905 		return (error);
906 	}
907 	*vpp = DETOV(dep);
908 	return (0);
909 }
910 
911 static int
912 msdosfs_vptofh(vp, fhp)
913 	struct vnode *vp;
914 	struct fid *fhp;
915 {
916 	struct denode *dep;
917 	struct defid *defhp;
918 
919 	dep = VTODE(vp);
920 	defhp = (struct defid *)fhp;
921 	defhp->defid_len = sizeof(struct defid);
922 	defhp->defid_dirclust = dep->de_dirclust;
923 	defhp->defid_dirofs = dep->de_diroffset;
924 	/* defhp->defid_gen = dep->de_gen; */
925 	return (0);
926 }
927 
928 static struct vfsops msdosfs_vfsops = {
929 	.vfs_fhtovp =		msdosfs_fhtovp,
930 	.vfs_init =		msdosfs_init,
931 	.vfs_omount =		msdosfs_omount,
932 	.vfs_root =		msdosfs_root,
933 	.vfs_statfs =		msdosfs_statfs,
934 	.vfs_sync =		msdosfs_sync,
935 	.vfs_uninit =		msdosfs_uninit,
936 	.vfs_unmount =		msdosfs_unmount,
937 	.vfs_vptofh =		msdosfs_vptofh,
938 };
939 
940 VFS_SET(msdosfs_vfsops, msdosfs, 0);
941 MODULE_VERSION(msdosfs, 1);
942