xref: /freebsd/sys/fs/msdosfs/msdosfs_vfsops.c (revision b52b9d56d4e96089873a75f9e29062eec19fabba)
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/mutex.h>
65 
66 #include <fs/msdosfs/bpb.h>
67 #include <fs/msdosfs/bootsect.h>
68 #include <fs/msdosfs/direntry.h>
69 #include <fs/msdosfs/denode.h>
70 #include <fs/msdosfs/msdosfsmount.h>
71 #include <fs/msdosfs/fat.h>
72 
73 #define MSDOSFS_DFLTBSIZE       4096
74 
75 #if 1 /*def PC98*/
76 /*
77  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
78  *       garbage or a random value :-{
79  *       If you want to use that broken-signatured media, define the
80  *       following symbol even though PC/AT.
81  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
82  */
83 #define	MSDOSFS_NOCHECKSIG
84 #endif
85 
86 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOSFS mount structure");
87 static MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOSFS file allocation table");
88 
89 static int	update_mp(struct mount *mp, struct msdosfs_args *argp);
90 static int	mountmsdosfs(struct vnode *devvp, struct mount *mp,
91 		    struct thread *td, struct msdosfs_args *argp);
92 static int	msdosfs_fhtovp(struct mount *, struct fid *, struct vnode **);
93 static int	msdosfs_mount(struct mount *, char *, caddr_t,
94 		    struct nameidata *, struct thread *);
95 static int	msdosfs_root(struct mount *, struct vnode **);
96 static int	msdosfs_statfs(struct mount *, struct statfs *,
97 		    struct thread *);
98 static int	msdosfs_sync(struct mount *, int, struct ucred *,
99 		    struct thread *);
100 static int	msdosfs_unmount(struct mount *, int, struct thread *);
101 static int	msdosfs_vptofh(struct vnode *, struct fid *);
102 
103 static int
104 update_mp(mp, argp)
105 	struct mount *mp;
106 	struct msdosfs_args *argp;
107 {
108 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
109 	int error;
110 
111 	pmp->pm_gid = argp->gid;
112 	pmp->pm_uid = argp->uid;
113 	pmp->pm_mask = argp->mask & ALLPERMS;
114 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
115 	if (pmp->pm_flags & MSDOSFSMNT_U2WTABLE) {
116 		bcopy(argp->u2w, pmp->pm_u2w, sizeof(pmp->pm_u2w));
117 		bcopy(argp->d2u, pmp->pm_d2u, sizeof(pmp->pm_d2u));
118 		bcopy(argp->u2d, pmp->pm_u2d, sizeof(pmp->pm_u2d));
119 	}
120 	if (pmp->pm_flags & MSDOSFSMNT_ULTABLE) {
121 		bcopy(argp->ul, pmp->pm_ul, sizeof(pmp->pm_ul));
122 		bcopy(argp->lu, pmp->pm_lu, sizeof(pmp->pm_lu));
123 	}
124 
125 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
126 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
127 	else if (!(pmp->pm_flags &
128 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
129 		struct vnode *rootvp;
130 
131 		/*
132 		 * Try to divine whether to support Win'95 long filenames
133 		 */
134 		if (FAT32(pmp))
135 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
136 		else {
137 			if ((error = msdosfs_root(mp, &rootvp)) != 0)
138 				return error;
139 			pmp->pm_flags |= findwin95(VTODE(rootvp))
140 				? MSDOSFSMNT_LONGNAME
141 					: MSDOSFSMNT_SHORTNAME;
142 			vput(rootvp);
143 		}
144 	}
145 	return 0;
146 }
147 
148 /*
149  * mp - path - addr in user space of mount point (ie /usr or whatever)
150  * data - addr in user space of mount params including the name of the block
151  * special file to treat as a filesystem.
152  */
153 static int
154 msdosfs_mount(mp, path, data, ndp, td)
155 	struct mount *mp;
156 	char *path;
157 	caddr_t data;
158 	struct nameidata *ndp;
159 	struct thread *td;
160 {
161 	struct vnode *devvp;	  /* vnode for blk device to mount */
162 	struct msdosfs_args args; /* will hold data from mount request */
163 	/* msdosfs specific mount control block */
164 	struct msdosfsmount *pmp = NULL;
165 	size_t size;
166 	int error, flags;
167 	mode_t accessmode;
168 
169 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
170 	if (error)
171 		return (error);
172 	if (args.magic != MSDOSFS_ARGSMAGIC)
173 		args.flags = 0;
174 	/*
175 	 * If updating, check whether changing from read-only to
176 	 * read/write; if there is no device name, that's all we do.
177 	 */
178 	if (mp->mnt_flag & MNT_UPDATE) {
179 		pmp = VFSTOMSDOSFS(mp);
180 		error = 0;
181 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
182 			flags = WRITECLOSE;
183 			if (mp->mnt_flag & MNT_FORCE)
184 				flags |= FORCECLOSE;
185 			error = vflush(mp, 0, flags);
186 		}
187 		if (!error && (mp->mnt_flag & MNT_RELOAD))
188 			/* not yet implemented */
189 			error = EOPNOTSUPP;
190 		if (error)
191 			return (error);
192 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
193 			/*
194 			 * If upgrade to read-write by non-root, then verify
195 			 * that user has necessary permissions on the device.
196 			 */
197 			if (suser(td)) {
198 				devvp = pmp->pm_devvp;
199 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
200 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
201 						   td->td_ucred, td);
202 				if (error) {
203 					VOP_UNLOCK(devvp, 0, td);
204 					return (error);
205 				}
206 				VOP_UNLOCK(devvp, 0, td);
207 			}
208 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
209 		}
210 		if (args.fspec == 0) {
211 #ifdef	__notyet__	/* doesn't work correctly with current mountd	XXX */
212 			if (args.flags & MSDOSFSMNT_MNTOPT) {
213 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
214 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
215 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
216 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
217 			}
218 #endif
219 			/*
220 			 * Process export requests.
221 			 */
222 			return (vfs_export(mp, &args.export));
223 		}
224 	}
225 	/*
226 	 * Not an update, or updating the name: look up the name
227 	 * and verify that it refers to a sensible block device.
228 	 */
229 	NDINIT(ndp, LOOKUP, FOLLOW, UIO_USERSPACE, args.fspec, td);
230 	error = namei(ndp);
231 	if (error)
232 		return (error);
233 	devvp = ndp->ni_vp;
234 	NDFREE(ndp, NDF_ONLY_PNBUF);
235 
236 	if (!vn_isdisk(devvp, &error)) {
237 		vrele(devvp);
238 		return (error);
239 	}
240 	/*
241 	 * If mount by non-root, then verify that user has necessary
242 	 * permissions on the device.
243 	 */
244 	if (suser(td)) {
245 		accessmode = VREAD;
246 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
247 			accessmode |= VWRITE;
248 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
249 		error = VOP_ACCESS(devvp, accessmode, td->td_ucred, td);
250 		if (error) {
251 			vput(devvp);
252 			return (error);
253 		}
254 		VOP_UNLOCK(devvp, 0, td);
255 	}
256 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
257 		error = mountmsdosfs(devvp, mp, td, &args);
258 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
259 		pmp = VFSTOMSDOSFS(mp);
260 #endif
261 	} else {
262 		if (devvp != pmp->pm_devvp)
263 			error = EINVAL;	/* XXX needs translation */
264 		else
265 			vrele(devvp);
266 	}
267 	if (error) {
268 		vrele(devvp);
269 		return (error);
270 	}
271 
272 	error = update_mp(mp, &args);
273 	if (error) {
274 		msdosfs_unmount(mp, MNT_FORCE, td);
275 		return error;
276 	}
277 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
278 	    &size);
279 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
280 	(void) msdosfs_statfs(mp, &mp->mnt_stat, td);
281 #ifdef MSDOSFS_DEBUG
282 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
283 #endif
284 	return (0);
285 }
286 
287 static int
288 mountmsdosfs(devvp, mp, td, argp)
289 	struct vnode *devvp;
290 	struct mount *mp;
291 	struct thread *td;
292 	struct msdosfs_args *argp;
293 {
294 	struct msdosfsmount *pmp;
295 	struct buf *bp;
296 	dev_t dev = devvp->v_rdev;
297 	union bootsector *bsp;
298 	struct byte_bpb33 *b33;
299 	struct byte_bpb50 *b50;
300 	struct byte_bpb710 *b710;
301 	u_int8_t SecPerClust;
302 	u_long clusters;
303 	int	ronly, error;
304 
305 	/*
306 	 * Disallow multiple mounts of the same device.
307 	 * Disallow mounting of a device that is currently in use
308 	 * (except for root, which might share swap device for miniroot).
309 	 * Flush out any old buffers remaining from a previous use.
310 	 */
311 	error = vfs_mountedon(devvp);
312 	if (error)
313 		return (error);
314 	if (vcount(devvp) > 1 && devvp != rootvp)
315 		return (EBUSY);
316 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
317 	error = vinvalbuf(devvp, V_SAVE, td->td_ucred, td, 0, 0);
318 	VOP_UNLOCK(devvp, 0, td);
319 	if (error)
320 		return (error);
321 
322 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
323 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, td);
324 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, td);
325 	VOP_UNLOCK(devvp, 0, td);
326 	if (error)
327 		return (error);
328 
329 	bp  = NULL; /* both used in error_exit */
330 	pmp = NULL;
331 
332 	/*
333 	 * Read the boot sector of the filesystem, and then check the
334 	 * boot signature.  If not a dos boot sector then error out.
335 	 *
336 	 * NOTE: 2048 is a maximum sector size in current...
337 	 */
338 	error = bread(devvp, 0, 2048, NOCRED, &bp);
339 	if (error)
340 		goto error_exit;
341 	bp->b_flags |= B_AGE;
342 	bsp = (union bootsector *)bp->b_data;
343 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
344 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
345 	b710 = (struct byte_bpb710 *)bsp->bs710.bsPBP;
346 
347 #ifndef MSDOSFS_NOCHECKSIG
348 	if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
349 	    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
350 		error = EINVAL;
351 		goto error_exit;
352 	}
353 #endif
354 
355 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
356 	pmp->pm_mountp = mp;
357 
358 	/*
359 	 * Compute several useful quantities from the bpb in the
360 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
361 	 * the fields that are different between dos 5 and dos 3.3.
362 	 */
363 	SecPerClust = b50->bpbSecPerClust;
364 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
365 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
366 	pmp->pm_FATs = b50->bpbFATs;
367 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
368 	pmp->pm_Sectors = getushort(b50->bpbSectors);
369 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
370 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
371 	pmp->pm_Heads = getushort(b50->bpbHeads);
372 	pmp->pm_Media = b50->bpbMedia;
373 
374 	/* calculate the ratio of sector size to DEV_BSIZE */
375 	pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
376 
377 	/* XXX - We should probably check more values here */
378 	if (!pmp->pm_BytesPerSec || !SecPerClust
379 		|| !pmp->pm_Heads || pmp->pm_Heads > 255
380 #ifdef PC98
381     		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) {
382 #else
383 		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
384 #endif
385 		error = EINVAL;
386 		goto error_exit;
387 	}
388 
389 	if (pmp->pm_Sectors == 0) {
390 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
391 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
392 	} else {
393 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
394 		pmp->pm_HugeSectors = pmp->pm_Sectors;
395 	}
396 	if (pmp->pm_HugeSectors > 0xffffffff /
397 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
398 		/*
399 		 * We cannot deal currently with this size of disk
400 		 * due to fileid limitations (see msdosfs_getattr and
401 		 * msdosfs_readdir)
402 		 */
403 		error = EINVAL;
404 		printf("mountmsdosfs(): disk too big, sorry\n");
405 		goto error_exit;
406 	}
407 
408 	if (pmp->pm_RootDirEnts == 0) {
409 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
410 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
411 		    || pmp->pm_Sectors
412 		    || pmp->pm_FATsecs
413 		    || getushort(b710->bpbFSVers)) {
414 			error = EINVAL;
415 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
416 			goto error_exit;
417 		}
418 		pmp->pm_fatmask = FAT32_MASK;
419 		pmp->pm_fatmult = 4;
420 		pmp->pm_fatdiv = 1;
421 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
422 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
423 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
424 		else
425 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
426 	} else
427 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
428 
429 	/*
430 	 * Check a few values (could do some more):
431 	 * - logical sector size: power of 2, >= block size
432 	 * - sectors per cluster: power of 2, >= 1
433 	 * - number of sectors:   >= 1, <= size of partition
434 	 */
435 	if ( (SecPerClust == 0)
436 	  || (SecPerClust & (SecPerClust - 1))
437 	  || (pmp->pm_BytesPerSec < DEV_BSIZE)
438 	  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
439 	  || (pmp->pm_HugeSectors == 0)
440 	) {
441 		error = EINVAL;
442 		goto error_exit;
443 	}
444 
445 	pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
446 	pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
447 	pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
448 	SecPerClust         *= pmp->pm_BlkPerSec;
449 
450 	pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
451 
452 	if (FAT32(pmp)) {
453 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
454 		pmp->pm_firstcluster = pmp->pm_fatblk
455 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
456 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
457 	} else {
458 		pmp->pm_rootdirblk = pmp->pm_fatblk +
459 			(pmp->pm_FATs * pmp->pm_FATsecs);
460 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
461 				       + DEV_BSIZE - 1)
462 			/ DEV_BSIZE; /* in blocks */
463 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
464 	}
465 
466 	pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
467 	    SecPerClust + 1;
468 	pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
469 
470 	if (pmp->pm_fatmask == 0) {
471 		if (pmp->pm_maxcluster
472 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
473 			/*
474 			 * This will usually be a floppy disk. This size makes
475 			 * sure that one fat entry will not be split across
476 			 * multiple blocks.
477 			 */
478 			pmp->pm_fatmask = FAT12_MASK;
479 			pmp->pm_fatmult = 3;
480 			pmp->pm_fatdiv = 2;
481 		} else {
482 			pmp->pm_fatmask = FAT16_MASK;
483 			pmp->pm_fatmult = 2;
484 			pmp->pm_fatdiv = 1;
485 		}
486 	}
487 
488 	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
489 	if (pmp->pm_maxcluster >= clusters) {
490 		printf("Warning: number of clusters (%ld) exceeds FAT "
491 		    "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
492 		pmp->pm_maxcluster = clusters - 1;
493 	}
494 
495 
496 	if (FAT12(pmp))
497 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
498 	else
499 		pmp->pm_fatblocksize = MSDOSFS_DFLTBSIZE;
500 
501 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
502 	pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
503 
504 	/*
505 	 * Compute mask and shift value for isolating cluster relative byte
506 	 * offsets and cluster numbers from a file offset.
507 	 */
508 	pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
509 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
510 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
511 
512 	/*
513 	 * Check for valid cluster size
514 	 * must be a power of 2
515 	 */
516 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
517 		error = EINVAL;
518 		goto error_exit;
519 	}
520 
521 	/*
522 	 * Release the bootsector buffer.
523 	 */
524 	brelse(bp);
525 	bp = NULL;
526 
527 	/*
528 	 * Check FSInfo.
529 	 */
530 	if (pmp->pm_fsinfo) {
531 		struct fsinfo *fp;
532 
533 		if ((error = bread(devvp, pmp->pm_fsinfo, fsi_size(pmp),
534 		    NOCRED, &bp)) != 0)
535 			goto error_exit;
536 		fp = (struct fsinfo *)bp->b_data;
537 		if (!bcmp(fp->fsisig1, "RRaA", 4)
538 		    && !bcmp(fp->fsisig2, "rrAa", 4)
539 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
540 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4))
541 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
542 		else
543 			pmp->pm_fsinfo = 0;
544 		brelse(bp);
545 		bp = NULL;
546 	}
547 
548 	/*
549 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?		XXX
550 	 */
551 
552 	/*
553 	 * Allocate memory for the bitmap of allocated clusters, and then
554 	 * fill it in.
555 	 */
556 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
557 				   / N_INUSEBITS)
558 				  * sizeof(*pmp->pm_inusemap),
559 				  M_MSDOSFSFAT, M_WAITOK);
560 
561 	/*
562 	 * fillinusemap() needs pm_devvp.
563 	 */
564 	pmp->pm_dev = dev;
565 	pmp->pm_devvp = devvp;
566 
567 	/*
568 	 * Have the inuse map filled in.
569 	 */
570 	if ((error = fillinusemap(pmp)) != 0)
571 		goto error_exit;
572 
573 	/*
574 	 * If they want fat updates to be synchronous then let them suffer
575 	 * the performance degradation in exchange for the on disk copy of
576 	 * the fat being correct just about all the time.  I suppose this
577 	 * would be a good thing to turn on if the kernel is still flakey.
578 	 */
579 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
580 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
581 
582 	/*
583 	 * Finish up.
584 	 */
585 	if (ronly)
586 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
587 	else
588 		pmp->pm_fmod = 1;
589 	mp->mnt_data = (qaddr_t) pmp;
590 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
591 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
592 	mp->mnt_flag |= MNT_LOCAL;
593 	devvp->v_rdev->si_mountpoint = mp;
594 
595 	return 0;
596 
597 error_exit:
598 	if (bp)
599 		brelse(bp);
600 	(void) VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE, NOCRED, td);
601 	if (pmp) {
602 		if (pmp->pm_inusemap)
603 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
604 		free(pmp, M_MSDOSFSMNT);
605 		mp->mnt_data = (qaddr_t)0;
606 	}
607 	return (error);
608 }
609 
610 /*
611  * Unmount the filesystem described by mp.
612  */
613 static int
614 msdosfs_unmount(mp, mntflags, td)
615 	struct mount *mp;
616 	int mntflags;
617 	struct thread *td;
618 {
619 	struct msdosfsmount *pmp;
620 	int error, flags;
621 
622 	flags = 0;
623 	if (mntflags & MNT_FORCE)
624 		flags |= FORCECLOSE;
625 	error = vflush(mp, 0, flags);
626 	if (error)
627 		return error;
628 	pmp = VFSTOMSDOSFS(mp);
629 	pmp->pm_devvp->v_rdev->si_mountpoint = NULL;
630 #ifdef MSDOSFS_DEBUG
631 	{
632 		struct vnode *vp = pmp->pm_devvp;
633 
634 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
635 		printf("flag %08lx, usecount %d, writecount %d, holdcnt %ld\n",
636 		    vp->v_flag, vp->v_usecount, vp->v_writecount, vp->v_holdcnt);
637 		printf("id %lu, mount %p, op %p\n",
638 		    vp->v_id, vp->v_mount, vp->v_op);
639 		printf("freef %p, freeb %p, mount %p\n",
640 		    TAILQ_NEXT(vp, v_freelist), vp->v_freelist.tqe_prev,
641 		    vp->v_mount);
642 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
643 		    TAILQ_FIRST(&vp->v_cleanblkhd),
644 		    TAILQ_FIRST(&vp->v_dirtyblkhd),
645 		    vp->v_numoutput, vp->v_type);
646 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
647 		    vp->v_socket, vp->v_tag,
648 		    ((u_int *)vp->v_data)[0],
649 		    ((u_int *)vp->v_data)[1]);
650 	}
651 #endif
652 	error = VOP_CLOSE(pmp->pm_devvp,
653 		    (pmp->pm_flags&MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE,
654 		    NOCRED, td);
655 	vrele(pmp->pm_devvp);
656 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
657 	free(pmp, M_MSDOSFSMNT);
658 	mp->mnt_data = (qaddr_t)0;
659 	mp->mnt_flag &= ~MNT_LOCAL;
660 	return (error);
661 }
662 
663 static int
664 msdosfs_root(mp, vpp)
665 	struct mount *mp;
666 	struct vnode **vpp;
667 {
668 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
669 	struct denode *ndep;
670 	int error;
671 
672 #ifdef MSDOSFS_DEBUG
673 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
674 #endif
675 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
676 	if (error)
677 		return (error);
678 	*vpp = DETOV(ndep);
679 	return (0);
680 }
681 
682 static int
683 msdosfs_statfs(mp, sbp, td)
684 	struct mount *mp;
685 	struct statfs *sbp;
686 	struct thread *td;
687 {
688 	struct msdosfsmount *pmp;
689 
690 	pmp = VFSTOMSDOSFS(mp);
691 	sbp->f_bsize = pmp->pm_bpcluster;
692 	sbp->f_iosize = pmp->pm_bpcluster;
693 	sbp->f_blocks = pmp->pm_maxcluster + 1;
694 	sbp->f_bfree = pmp->pm_freeclustercount;
695 	sbp->f_bavail = pmp->pm_freeclustercount;
696 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
697 	sbp->f_ffree = 0;	/* what to put in here? */
698 	if (sbp != &mp->mnt_stat) {
699 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
700 		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
701 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
702 	}
703 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
704 	return (0);
705 }
706 
707 static int
708 msdosfs_sync(mp, waitfor, cred, td)
709 	struct mount *mp;
710 	int waitfor;
711 	struct ucred *cred;
712 	struct thread *td;
713 {
714 	struct vnode *vp, *nvp;
715 	struct denode *dep;
716 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
717 	int error, allerror = 0;
718 
719 	/*
720 	 * If we ever switch to not updating all of the fats all the time,
721 	 * this would be the place to update them from the first one.
722 	 */
723 	if (pmp->pm_fmod != 0) {
724 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
725 			panic("msdosfs_sync: rofs mod");
726 		else {
727 			/* update fats here */
728 		}
729 	}
730 	/*
731 	 * Write back each (modified) denode.
732 	 */
733 	mtx_lock(&mntvnode_mtx);
734 loop:
735 	for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist); vp != NULL; vp = nvp) {
736 		/*
737 		 * If the vnode that we are about to sync is no longer
738 		 * associated with this mount point, start over.
739 		 */
740 		if (vp->v_mount != mp)
741 			goto loop;
742 		nvp = TAILQ_NEXT(vp, v_nmntvnodes);
743 
744 		mtx_unlock(&mntvnode_mtx);
745 		mtx_lock(&vp->v_interlock);
746 		dep = VTODE(vp);
747 		if (vp->v_type == VNON ||
748 		    ((dep->de_flag &
749 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
750 		    (TAILQ_EMPTY(&vp->v_dirtyblkhd) || waitfor == MNT_LAZY))) {
751 			mtx_unlock(&vp->v_interlock);
752 			mtx_lock(&mntvnode_mtx);
753 			continue;
754 		}
755 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, td);
756 		if (error) {
757 			mtx_lock(&mntvnode_mtx);
758 			if (error == ENOENT)
759 				goto loop;
760 			continue;
761 		}
762 		error = VOP_FSYNC(vp, cred, waitfor, td);
763 		if (error)
764 			allerror = error;
765 		VOP_UNLOCK(vp, 0, td);
766 		vrele(vp);
767 		mtx_lock(&mntvnode_mtx);
768 	}
769 	mtx_unlock(&mntvnode_mtx);
770 
771 	/*
772 	 * Flush filesystem control info.
773 	 */
774 	if (waitfor != MNT_LAZY) {
775 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY, td);
776 		error = VOP_FSYNC(pmp->pm_devvp, cred, waitfor, td);
777 		if (error)
778 			allerror = error;
779 		VOP_UNLOCK(pmp->pm_devvp, 0, td);
780 	}
781 	return (allerror);
782 }
783 
784 static int
785 msdosfs_fhtovp(mp, fhp, vpp)
786 	struct mount *mp;
787 	struct fid *fhp;
788 	struct vnode **vpp;
789 {
790 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
791 	struct defid *defhp = (struct defid *) fhp;
792 	struct denode *dep;
793 	int error;
794 
795 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
796 	if (error) {
797 		*vpp = NULLVP;
798 		return (error);
799 	}
800 	*vpp = DETOV(dep);
801 	return (0);
802 }
803 
804 static int
805 msdosfs_vptofh(vp, fhp)
806 	struct vnode *vp;
807 	struct fid *fhp;
808 {
809 	struct denode *dep;
810 	struct defid *defhp;
811 
812 	dep = VTODE(vp);
813 	defhp = (struct defid *)fhp;
814 	defhp->defid_len = sizeof(struct defid);
815 	defhp->defid_dirclust = dep->de_dirclust;
816 	defhp->defid_dirofs = dep->de_diroffset;
817 	/* defhp->defid_gen = dep->de_gen; */
818 	return (0);
819 }
820 
821 static struct vfsops msdosfs_vfsops = {
822 	msdosfs_mount,
823 	vfs_stdstart,
824 	msdosfs_unmount,
825 	msdosfs_root,
826 	vfs_stdquotactl,
827 	msdosfs_statfs,
828 	msdosfs_sync,
829 	vfs_stdvget,
830 	msdosfs_fhtovp,
831 	vfs_stdcheckexp,
832 	msdosfs_vptofh,
833 	msdosfs_init,
834 	msdosfs_uninit,
835 	vfs_stdextattrctl,
836 };
837 
838 VFS_SET(msdosfs_vfsops, msdosfs, 0);
839