xref: /freebsd/sys/fs/msdosfs/msdosfs_vfsops.c (revision 4cf49a43559ed9fdad601bdcccd2c55963008675)
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/buf.h>
60 #include <sys/fcntl.h>
61 #include <sys/malloc.h>
62 #include <sys/stat.h> 				/* defines ALLPERMS */
63 
64 #include <msdosfs/bpb.h>
65 #include <msdosfs/bootsect.h>
66 #include <msdosfs/direntry.h>
67 #include <msdosfs/denode.h>
68 #include <msdosfs/msdosfsmount.h>
69 #include <msdosfs/fat.h>
70 
71 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOSFS mount structure");
72 static MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS FAT", "MSDOSFS file allocation table");
73 
74 static int	update_mp __P((struct mount *mp, struct msdosfs_args *argp));
75 static int	mountmsdosfs __P((struct vnode *devvp, struct mount *mp,
76 				  struct proc *p, struct msdosfs_args *argp));
77 static int	msdosfs_fhtovp __P((struct mount *, struct fid *,
78 				    struct vnode **));
79 static int	msdosfs_checkexp __P((struct mount *, struct sockaddr *,
80 				    int *, struct ucred **));
81 static int	msdosfs_mount __P((struct mount *, char *, caddr_t,
82 				   struct nameidata *, struct proc *));
83 static int	msdosfs_root __P((struct mount *, struct vnode **));
84 static int	msdosfs_statfs __P((struct mount *, struct statfs *,
85 				    struct proc *));
86 static int	msdosfs_sync __P((struct mount *, int, struct ucred *,
87 				  struct proc *));
88 static int	msdosfs_unmount __P((struct mount *, int, struct proc *));
89 static int	msdosfs_vptofh __P((struct vnode *, struct fid *));
90 
91 static int
92 update_mp(mp, argp)
93 	struct mount *mp;
94 	struct msdosfs_args *argp;
95 {
96 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
97 	int error;
98 
99 	pmp->pm_gid = argp->gid;
100 	pmp->pm_uid = argp->uid;
101 	pmp->pm_mask = argp->mask & ALLPERMS;
102 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
103 	if (pmp->pm_flags & MSDOSFSMNT_U2WTABLE) {
104 		bcopy(argp->u2w, pmp->pm_u2w, sizeof(pmp->pm_u2w));
105 		bcopy(argp->d2u, pmp->pm_d2u, sizeof(pmp->pm_d2u));
106 		bcopy(argp->u2d, pmp->pm_u2d, sizeof(pmp->pm_u2d));
107 	}
108 	if (pmp->pm_flags & MSDOSFSMNT_ULTABLE) {
109 		bcopy(argp->ul, pmp->pm_ul, sizeof(pmp->pm_ul));
110 		bcopy(argp->lu, pmp->pm_lu, sizeof(pmp->pm_lu));
111 	}
112 
113 #ifndef __FreeBSD__
114 	/*
115 	 * GEMDOS knows nothing (yet) about win95
116 	 */
117 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
118 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
119 #endif
120 
121 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
122 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
123 	else if (!(pmp->pm_flags &
124 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
125 		struct vnode *rootvp;
126 
127 		/*
128 		 * Try to divine whether to support Win'95 long filenames
129 		 */
130 		if (FAT32(pmp))
131 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
132 		else {
133 			if ((error = msdosfs_root(mp, &rootvp)) != 0)
134 				return error;
135 			pmp->pm_flags |= findwin95(VTODE(rootvp))
136 				? MSDOSFSMNT_LONGNAME
137 					: MSDOSFSMNT_SHORTNAME;
138 			vput(rootvp);
139 		}
140 	}
141 	return 0;
142 }
143 
144 #ifndef __FreeBSD__
145 int
146 msdosfs_mountroot()
147 {
148 	register struct mount *mp;
149 	struct proc *p = curproc;	/* XXX */
150 	size_t size;
151 	int error;
152 	struct msdosfs_args args;
153 
154 	if (root_device->dv_class != DV_DISK)
155 		return (ENODEV);
156 
157 	/*
158 	 * Get vnodes for swapdev and rootdev.
159 	 */
160 	if (bdevvp(rootdev, &rootvp))
161 		panic("msdosfs_mountroot: can't setup rootvp");
162 
163 	mp = malloc((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK);
164 	bzero((char *)mp, (u_long)sizeof(struct mount));
165 	mp->mnt_op = &msdosfs_vfsops;
166 	mp->mnt_flag = 0;
167 	LIST_INIT(&mp->mnt_vnodelist);
168 
169 	args.flags = 0;
170 	args.uid = 0;
171 	args.gid = 0;
172 	args.mask = 0777;
173 
174 	if ((error = mountmsdosfs(rootvp, mp, p, &args)) != 0) {
175 		free(mp, M_MOUNT);
176 		return (error);
177 	}
178 
179 	if ((error = update_mp(mp, &args)) != 0) {
180 		(void)msdosfs_unmount(mp, 0, p);
181 		free(mp, M_MOUNT);
182 		return (error);
183 	}
184 
185 	if ((error = vfs_lock(mp)) != 0) {
186 		(void)msdosfs_unmount(mp, 0, p);
187 		free(mp, M_MOUNT);
188 		return (error);
189 	}
190 
191 	CIRCLEQ_INSERT_TAIL(&mountlist, mp, mnt_list);
192 	mp->mnt_vnodecovered = NULLVP;
193 	(void) copystr("/", mp->mnt_stat.f_mntonname, MNAMELEN - 1,
194 	    &size);
195 	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
196 	(void) copystr(ROOTNAME, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
197 	    &size);
198 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
199 	(void)msdosfs_statfs(mp, &mp->mnt_stat, p);
200 	vfs_unlock(mp);
201 	return (0);
202 }
203 #endif
204 
205 /*
206  * mp - path - addr in user space of mount point (ie /usr or whatever)
207  * data - addr in user space of mount params including the name of the block
208  * special file to treat as a filesystem.
209  */
210 static int
211 msdosfs_mount(mp, path, data, ndp, p)
212 	struct mount *mp;
213 	char *path;
214 	caddr_t data;
215 	struct nameidata *ndp;
216 	struct proc *p;
217 {
218 	struct vnode *devvp;	  /* vnode for blk device to mount */
219 	struct msdosfs_args args; /* will hold data from mount request */
220 	/* msdosfs specific mount control block */
221 	struct msdosfsmount *pmp = NULL;
222 	size_t size;
223 	int error, flags;
224 	mode_t accessmode;
225 
226 	error = copyin(data, (caddr_t)&args, sizeof(struct msdosfs_args));
227 	if (error)
228 		return (error);
229 	if (args.magic != MSDOSFS_ARGSMAGIC)
230 		args.flags = 0;
231 	/*
232 	 * If updating, check whether changing from read-only to
233 	 * read/write; if there is no device name, that's all we do.
234 	 */
235 	if (mp->mnt_flag & MNT_UPDATE) {
236 		pmp = VFSTOMSDOSFS(mp);
237 		error = 0;
238 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
239 			flags = WRITECLOSE;
240 			if (mp->mnt_flag & MNT_FORCE)
241 				flags |= FORCECLOSE;
242 			error = vflush(mp, NULLVP, flags);
243 		}
244 		if (!error && (mp->mnt_flag & MNT_RELOAD))
245 			/* not yet implemented */
246 			error = EOPNOTSUPP;
247 		if (error)
248 			return (error);
249 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
250 			/*
251 			 * If upgrade to read-write by non-root, then verify
252 			 * that user has necessary permissions on the device.
253 			 */
254 			if (p->p_ucred->cr_uid != 0) {
255 				devvp = pmp->pm_devvp;
256 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
257 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
258 						   p->p_ucred, p);
259 				if (error) {
260 					VOP_UNLOCK(devvp, 0, p);
261 					return (error);
262 				}
263 				VOP_UNLOCK(devvp, 0, p);
264 			}
265 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
266 		}
267 		if (args.fspec == 0) {
268 #ifdef	__notyet__		/* doesn't work correctly with current mountd	XXX */
269 			if (args.flags & MSDOSFSMNT_MNTOPT) {
270 				pmp->pm_flags &= ~MSDOSFSMNT_MNTOPT;
271 				pmp->pm_flags |= args.flags & MSDOSFSMNT_MNTOPT;
272 				if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
273 					pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
274 			}
275 #endif
276 			/*
277 			 * Process export requests.
278 			 */
279 			return (vfs_export(mp, &pmp->pm_export, &args.export));
280 		}
281 	}
282 	/*
283 	 * Not an update, or updating the name: look up the name
284 	 * and verify that it refers to a sensible block device.
285 	 */
286 	NDINIT(ndp, LOOKUP, FOLLOW, UIO_USERSPACE, args.fspec, p);
287 	error = namei(ndp);
288 	if (error)
289 		return (error);
290 	devvp = ndp->ni_vp;
291 
292 	if (!vn_isdisk(devvp)) {
293 		vrele(devvp);
294 		return (ENOTBLK);
295 	}
296 	/*
297 	 * If mount by non-root, then verify that user has necessary
298 	 * permissions on the device.
299 	 */
300 	if (p->p_ucred->cr_uid != 0) {
301 		accessmode = VREAD;
302 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
303 			accessmode |= VWRITE;
304 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
305 		error = VOP_ACCESS(devvp, accessmode, p->p_ucred, p);
306 		if (error) {
307 			vput(devvp);
308 			return (error);
309 		}
310 		VOP_UNLOCK(devvp, 0, p);
311 	}
312 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
313 		error = mountmsdosfs(devvp, mp, p, &args);
314 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
315 		pmp = VFSTOMSDOSFS(mp);
316 #endif
317 	} else {
318 		if (devvp != pmp->pm_devvp)
319 			error = EINVAL;	/* XXX needs translation */
320 		else
321 			vrele(devvp);
322 	}
323 	if (error) {
324 		vrele(devvp);
325 		return (error);
326 	}
327 
328 	error = update_mp(mp, &args);
329 	if (error) {
330 		msdosfs_unmount(mp, MNT_FORCE, p);
331 		return error;
332 	}
333 
334 	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
335 	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
336 	(void) copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
337 	    &size);
338 	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
339 	(void) msdosfs_statfs(mp, &mp->mnt_stat, p);
340 #ifdef MSDOSFS_DEBUG
341 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
342 #endif
343 	return (0);
344 }
345 
346 static int
347 mountmsdosfs(devvp, mp, p, argp)
348 	struct vnode *devvp;
349 	struct mount *mp;
350 	struct proc *p;
351 	struct msdosfs_args *argp;
352 {
353 	struct msdosfsmount *pmp;
354 	struct buf *bp;
355 	dev_t dev = devvp->v_rdev;
356 #ifndef __FreeBSD__
357 	struct partinfo dpart;
358 	int bsize = 0, dtype = 0, tmp;
359 #endif
360 	union bootsector *bsp;
361 	struct byte_bpb33 *b33;
362 	struct byte_bpb50 *b50;
363 	struct byte_bpb710 *b710;
364 	u_int8_t SecPerClust;
365 	int	ronly, error;
366 
367 	/*
368 	 * Disallow multiple mounts of the same device.
369 	 * Disallow mounting of a device that is currently in use
370 	 * (except for root, which might share swap device for miniroot).
371 	 * Flush out any old buffers remaining from a previous use.
372 	 */
373 	error = vfs_mountedon(devvp);
374 	if (error)
375 		return (error);
376 	if (vcount(devvp) > 1 && devvp != rootvp)
377 		return (EBUSY);
378 	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
379 	error = vinvalbuf(devvp, V_SAVE, p->p_ucred, p, 0, 0);
380 	VOP_UNLOCK(devvp, 0, p);
381 	if (error)
382 		return (error);
383 
384 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
385 	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, FSCRED, p);
386 	if (error)
387 		return (error);
388 
389 	bp  = NULL; /* both used in error_exit */
390 	pmp = NULL;
391 
392 #ifndef __FreeBSD__
393 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
394 		/*
395 	 	 * We need the disklabel to calculate the size of a FAT entry
396 		 * later on. Also make sure the partition contains a filesystem
397 		 * of type FS_MSDOS. This doesn't work for floppies, so we have
398 		 * to check for them too.
399 	 	 *
400 	 	 * At least some parts of the msdos fs driver seem to assume
401 		 * that the size of a disk block will always be 512 bytes.
402 		 * Let's check it...
403 		 */
404 		error = VOP_IOCTL(devvp, DIOCGPART, (caddr_t)&dpart,
405 				  FREAD, NOCRED, p);
406 		if (error)
407 			goto error_exit;
408 		tmp   = dpart.part->p_fstype;
409 		dtype = dpart.disklab->d_type;
410 		bsize = dpart.disklab->d_secsize;
411 		if (bsize != 512 || (dtype!=DTYPE_FLOPPY && tmp!=FS_MSDOS)) {
412 			error = EINVAL;
413 			goto error_exit;
414 		}
415 	}
416 #endif
417 
418 	/*
419 	 * Read the boot sector of the filesystem, and then check the
420 	 * boot signature.  If not a dos boot sector then error out.
421 	 */
422 #ifdef	PC98
423 	error = bread(devvp, 0, 1024, NOCRED, &bp);
424 #else
425 	error = bread(devvp, 0, 512, NOCRED, &bp);
426 #endif
427 	if (error)
428 		goto error_exit;
429 	bp->b_flags |= B_AGE;
430 	bsp = (union bootsector *)bp->b_data;
431 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
432 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
433 	b710 = (struct byte_bpb710 *)bsp->bs710.bsPBP;
434 
435 #ifndef __FreeBSD__
436 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
437 #endif
438 #ifdef PC98
439 		if ((bsp->bs50.bsBootSectSig0 != BOOTSIG0
440 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1)
441 		    && (bsp->bs50.bsBootSectSig0 != 0       /* PC98 DOS 3.3x */
442 		    || bsp->bs50.bsBootSectSig1 != 0)
443 		    && (bsp->bs50.bsBootSectSig0 != 0x90    /* PC98 DOS 5.0  */
444 		    || bsp->bs50.bsBootSectSig1 != 0x3d)
445 		    && (bsp->bs50.bsBootSectSig0 != 0x46    /* PC98 DOS 3.3B */
446 		    || bsp->bs50.bsBootSectSig1 != 0xfa)) {
447 #else
448 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
449 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
450 #endif
451 			error = EINVAL;
452 			goto error_exit;
453 		}
454 #ifndef __FreeBSD__
455 	}
456 #endif
457 
458 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK);
459 	bzero((caddr_t)pmp, sizeof *pmp);
460 	pmp->pm_mountp = mp;
461 
462 	/*
463 	 * Compute several useful quantities from the bpb in the
464 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
465 	 * the fields that are different between dos 5 and dos 3.3.
466 	 */
467 	SecPerClust = b50->bpbSecPerClust;
468 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
469 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
470 	pmp->pm_FATs = b50->bpbFATs;
471 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
472 	pmp->pm_Sectors = getushort(b50->bpbSectors);
473 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
474 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
475 	pmp->pm_Heads = getushort(b50->bpbHeads);
476 	pmp->pm_Media = b50->bpbMedia;
477 
478 #ifndef __FreeBSD__
479 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
480 #endif
481 		/* XXX - We should probably check more values here */
482 		if (!pmp->pm_BytesPerSec || !SecPerClust
483 			|| !pmp->pm_Heads || pmp->pm_Heads > 255
484 #ifdef PC98
485 	    		|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) {
486 #else
487 			|| !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) {
488 #endif
489 			error = EINVAL;
490 			goto error_exit;
491 		}
492 #ifndef __FreeBSD__
493 	}
494 #endif
495 
496 	if (pmp->pm_Sectors == 0) {
497 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
498 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
499 	} else {
500 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
501 		pmp->pm_HugeSectors = pmp->pm_Sectors;
502 	}
503 	if (pmp->pm_HugeSectors > 0xffffffff /
504 	    (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
505 		/*
506 		 * We cannot deal currently with this size of disk
507 		 * due to fileid limitations (see msdosfs_getattr and
508 		 * msdosfs_readdir)
509 		 */
510 		error = EINVAL;
511 		printf("mountmsdosfs(): disk too big, sorry\n");
512 		goto error_exit;
513 	}
514 
515 	if (pmp->pm_RootDirEnts == 0) {
516 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
517 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
518 		    || pmp->pm_Sectors
519 		    || pmp->pm_FATsecs
520 		    || getushort(b710->bpbFSVers)) {
521 			error = EINVAL;
522 			printf("mountmsdosfs(): bad FAT32 filesystem\n");
523 			goto error_exit;
524 		}
525 		pmp->pm_fatmask = FAT32_MASK;
526 		pmp->pm_fatmult = 4;
527 		pmp->pm_fatdiv = 1;
528 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
529 		if (getushort(b710->bpbExtFlags) & FATMIRROR)
530 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
531 		else
532 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
533 	} else
534 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
535 
536 #ifndef __FreeBSD__
537 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
538 		if (FAT32(pmp)) {
539 			/*
540 			 * GEMDOS doesn't know fat32.
541 			 */
542 			error = EINVAL;
543 			goto error_exit;
544 		}
545 
546 		/*
547 		 * Check a few values (could do some more):
548 		 * - logical sector size: power of 2, >= block size
549 		 * - sectors per cluster: power of 2, >= 1
550 		 * - number of sectors:   >= 1, <= size of partition
551 		 */
552 		if ( (SecPerClust == 0)
553 		  || (SecPerClust & (SecPerClust - 1))
554 		  || (pmp->pm_BytesPerSec < bsize)
555 		  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
556 		  || (pmp->pm_HugeSectors == 0)
557 		  || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize)
558 							> dpart.part->p_size)
559 		   ) {
560 			error = EINVAL;
561 			goto error_exit;
562 		}
563 		/*
564 		 * XXX - Many parts of the msdos fs driver seem to assume that
565 		 * the number of bytes per logical sector (BytesPerSec) will
566 		 * always be the same as the number of bytes per disk block
567 		 * Let's pretend it is.
568 		 */
569 		tmp = pmp->pm_BytesPerSec / bsize;
570 		pmp->pm_BytesPerSec  = bsize;
571 		pmp->pm_HugeSectors *= tmp;
572 		pmp->pm_HiddenSects *= tmp;
573 		pmp->pm_ResSectors  *= tmp;
574 		pmp->pm_Sectors     *= tmp;
575 		pmp->pm_FATsecs     *= tmp;
576 		SecPerClust         *= tmp;
577 	}
578 #endif
579 	pmp->pm_fatblk = pmp->pm_ResSectors;
580 	if (FAT32(pmp)) {
581 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
582 		pmp->pm_firstcluster = pmp->pm_fatblk
583 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
584 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
585 	} else {
586 		pmp->pm_rootdirblk = pmp->pm_fatblk +
587 			(pmp->pm_FATs * pmp->pm_FATsecs);
588 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
589 				       + pmp->pm_BytesPerSec - 1)
590 			/ pmp->pm_BytesPerSec;/* in sectors */
591 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
592 	}
593 
594 	pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
595 	    SecPerClust;
596 	pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
597 	pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
598 
599 #ifndef __FreeBSD__
600 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
601 		if ((pmp->pm_nmbrofclusters <= (0xff0 - 2))
602 		      && ((dtype == DTYPE_FLOPPY) || ((dtype == DTYPE_VNODE)
603 		      && ((pmp->pm_Heads == 1) || (pmp->pm_Heads == 2))))
604 		    ) {
605 			pmp->pm_fatmask = FAT12_MASK;
606 			pmp->pm_fatmult = 3;
607 			pmp->pm_fatdiv = 2;
608 		} else {
609 			pmp->pm_fatmask = FAT16_MASK;
610 			pmp->pm_fatmult = 2;
611 			pmp->pm_fatdiv = 1;
612 		}
613 	} else
614 #endif
615 	if (pmp->pm_fatmask == 0) {
616 		if (pmp->pm_maxcluster
617 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
618 			/*
619 			 * This will usually be a floppy disk. This size makes
620 			 * sure that one fat entry will not be split across
621 			 * multiple blocks.
622 			 */
623 			pmp->pm_fatmask = FAT12_MASK;
624 			pmp->pm_fatmult = 3;
625 			pmp->pm_fatdiv = 2;
626 		} else {
627 			pmp->pm_fatmask = FAT16_MASK;
628 			pmp->pm_fatmult = 2;
629 			pmp->pm_fatdiv = 1;
630 		}
631 	}
632 	if (FAT12(pmp))
633 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
634 	else
635 		pmp->pm_fatblocksize = DFLTBSIZE;
636 
637 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
638 	pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 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 * pmp->pm_BytesPerSec;
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 FSInfo.
665 	 */
666 	if (pmp->pm_fsinfo) {
667 		struct fsinfo *fp;
668 
669 		if ((error = bread(devvp, pmp->pm_fsinfo, 1024, NOCRED, &bp)) != 0)
670 			goto error_exit;
671 		fp = (struct fsinfo *)bp->b_data;
672 		if (!bcmp(fp->fsisig1, "RRaA", 4)
673 		    && !bcmp(fp->fsisig2, "rrAa", 4)
674 		    && !bcmp(fp->fsisig3, "\0\0\125\252", 4)
675 		    && !bcmp(fp->fsisig4, "\0\0\125\252", 4))
676 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
677 		else
678 			pmp->pm_fsinfo = 0;
679 		brelse(bp);
680 		bp = NULL;
681 	}
682 
683 	/*
684 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?		XXX
685 	 */
686 
687 	/*
688 	 * Allocate memory for the bitmap of allocated clusters, and then
689 	 * fill it in.
690 	 */
691 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
692 				   / N_INUSEBITS)
693 				  * sizeof(*pmp->pm_inusemap),
694 				  M_MSDOSFSFAT, M_WAITOK);
695 
696 	/*
697 	 * fillinusemap() needs pm_devvp.
698 	 */
699 	pmp->pm_dev = dev;
700 	pmp->pm_devvp = devvp;
701 
702 	/*
703 	 * Have the inuse map filled in.
704 	 */
705 	if ((error = fillinusemap(pmp)) != 0)
706 		goto error_exit;
707 
708 	/*
709 	 * If they want fat updates to be synchronous then let them suffer
710 	 * the performance degradation in exchange for the on disk copy of
711 	 * the fat being correct just about all the time.  I suppose this
712 	 * would be a good thing to turn on if the kernel is still flakey.
713 	 */
714 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
715 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
716 
717 	/*
718 	 * Finish up.
719 	 */
720 	if (ronly)
721 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
722 	else
723 		pmp->pm_fmod = 1;
724 	mp->mnt_data = (qaddr_t) pmp;
725 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
726 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
727 	mp->mnt_flag |= MNT_LOCAL;
728 	devvp->v_specmountpoint = mp;
729 
730 	return 0;
731 
732 error_exit:
733 	if (bp)
734 		brelse(bp);
735 	(void) VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE, NOCRED, p);
736 	if (pmp) {
737 		if (pmp->pm_inusemap)
738 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
739 		free(pmp, M_MSDOSFSMNT);
740 		mp->mnt_data = (qaddr_t)0;
741 	}
742 	return (error);
743 }
744 
745 /*
746  * Unmount the filesystem described by mp.
747  */
748 static int
749 msdosfs_unmount(mp, mntflags, p)
750 	struct mount *mp;
751 	int mntflags;
752 	struct proc *p;
753 {
754 	struct msdosfsmount *pmp;
755 	int error, flags;
756 
757 	flags = 0;
758 	if (mntflags & MNT_FORCE)
759 		flags |= FORCECLOSE;
760 	error = vflush(mp, NULLVP, flags);
761 	if (error)
762 		return error;
763 	pmp = VFSTOMSDOSFS(mp);
764 	pmp->pm_devvp->v_specmountpoint = NULL;
765 #ifdef MSDOSFS_DEBUG
766 	{
767 		struct vnode *vp = pmp->pm_devvp;
768 
769 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
770 		printf("flag %08lx, usecount %d, writecount %d, holdcnt %ld\n",
771 		    vp->v_flag, vp->v_usecount, vp->v_writecount, vp->v_holdcnt);
772 		printf("id %lu, mount %p, op %p\n",
773 		    vp->v_id, vp->v_mount, vp->v_op);
774 		printf("freef %p, freeb %p, mount %p\n",
775 		    vp->v_freelist.tqe_next, vp->v_freelist.tqe_prev,
776 		    vp->v_mount);
777 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
778 		    TAILQ_FIRST(&vp->v_cleanblkhd),
779 		    TAILQ_FIRST(&vp->v_dirtyblkhd),
780 		    vp->v_numoutput, vp->v_type);
781 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
782 		    vp->v_socket, vp->v_tag,
783 		    ((u_int *)vp->v_data)[0],
784 		    ((u_int *)vp->v_data)[1]);
785 	}
786 #endif
787 	error = VOP_CLOSE(pmp->pm_devvp,
788 		    (pmp->pm_flags&MSDOSFSMNT_RONLY) ? FREAD : FREAD | FWRITE,
789 		    NOCRED, p);
790 	vrele(pmp->pm_devvp);
791 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
792 	free(pmp, M_MSDOSFSMNT);
793 	mp->mnt_data = (qaddr_t)0;
794 	mp->mnt_flag &= ~MNT_LOCAL;
795 	return (error);
796 }
797 
798 static int
799 msdosfs_root(mp, vpp)
800 	struct mount *mp;
801 	struct vnode **vpp;
802 {
803 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
804 	struct denode *ndep;
805 	int error;
806 
807 #ifdef MSDOSFS_DEBUG
808 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
809 #endif
810 	error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
811 	if (error)
812 		return (error);
813 	*vpp = DETOV(ndep);
814 	return (0);
815 }
816 
817 static int
818 msdosfs_statfs(mp, sbp, p)
819 	struct mount *mp;
820 	struct statfs *sbp;
821 	struct proc *p;
822 {
823 	struct msdosfsmount *pmp;
824 
825 	pmp = VFSTOMSDOSFS(mp);
826 	sbp->f_bsize = pmp->pm_bpcluster;
827 	sbp->f_iosize = pmp->pm_bpcluster;
828 	sbp->f_blocks = pmp->pm_nmbrofclusters;
829 	sbp->f_bfree = pmp->pm_freeclustercount;
830 	sbp->f_bavail = pmp->pm_freeclustercount;
831 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
832 	sbp->f_ffree = 0;	/* what to put in here? */
833 	if (sbp != &mp->mnt_stat) {
834 		sbp->f_type = mp->mnt_vfc->vfc_typenum;
835 		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
836 		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
837 	}
838 	strncpy(sbp->f_fstypename, mp->mnt_vfc->vfc_name, MFSNAMELEN);
839 	return (0);
840 }
841 
842 static int
843 msdosfs_sync(mp, waitfor, cred, p)
844 	struct mount *mp;
845 	int waitfor;
846 	struct ucred *cred;
847 	struct proc *p;
848 {
849 	struct vnode *vp, *nvp;
850 	struct denode *dep;
851 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
852 	int error, allerror = 0;
853 
854 	/*
855 	 * If we ever switch to not updating all of the fats all the time,
856 	 * this would be the place to update them from the first one.
857 	 */
858 	if (pmp->pm_fmod != 0) {
859 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
860 			panic("msdosfs_sync: rofs mod");
861 		else {
862 			/* update fats here */
863 		}
864 	}
865 	/*
866 	 * Write back each (modified) denode.
867 	 */
868 	simple_lock(&mntvnode_slock);
869 loop:
870 	for (vp = mp->mnt_vnodelist.lh_first; vp != NULL; vp = nvp) {
871 		/*
872 		 * If the vnode that we are about to sync is no longer
873 		 * associated with this mount point, start over.
874 		 */
875 		if (vp->v_mount != mp)
876 			goto loop;
877 
878 		simple_lock(&vp->v_interlock);
879 		nvp = vp->v_mntvnodes.le_next;
880 		dep = VTODE(vp);
881 		if (vp->v_type == VNON ||
882 		    ((dep->de_flag &
883 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
884 		    (TAILQ_EMPTY(&vp->v_dirtyblkhd) || waitfor == MNT_LAZY))) {
885 			simple_unlock(&vp->v_interlock);
886 			continue;
887 		}
888 		simple_unlock(&mntvnode_slock);
889 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, p);
890 		if (error) {
891 			simple_lock(&mntvnode_slock);
892 			if (error == ENOENT)
893 				goto loop;
894 			continue;
895 		}
896 		error = VOP_FSYNC(vp, cred, waitfor, p);
897 		if (error)
898 			allerror = error;
899 		VOP_UNLOCK(vp, 0, p);
900 		vrele(vp);
901 		simple_lock(&mntvnode_slock);
902 	}
903 	simple_unlock(&mntvnode_slock);
904 
905 	/*
906 	 * Flush filesystem control info.
907 	 */
908 	if (waitfor != MNT_LAZY) {
909 		vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY, p);
910 		error = VOP_FSYNC(pmp->pm_devvp, cred, waitfor, p);
911 		if (error)
912 			allerror = error;
913 		VOP_UNLOCK(pmp->pm_devvp, 0, p);
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 	return (0);
936 }
937 
938 static int
939 msdosfs_checkexp(mp, nam,  exflagsp, credanonp)
940 	struct mount *mp;
941 	struct sockaddr *nam;
942 	int *exflagsp;
943 	struct ucred **credanonp;
944 {
945 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
946 	struct netcred *np;
947 
948 	np = vfs_export_lookup(mp, &pmp->pm_export, nam);
949 	if (np == NULL)
950 		return (EACCES);
951 	*exflagsp = np->netc_exflags;
952 	*credanonp = &np->netc_anon;
953 	return (0);
954 }
955 
956 static int
957 msdosfs_vptofh(vp, fhp)
958 	struct vnode *vp;
959 	struct fid *fhp;
960 {
961 	struct denode *dep;
962 	struct defid *defhp;
963 
964 	dep = VTODE(vp);
965 	defhp = (struct defid *)fhp;
966 	defhp->defid_len = sizeof(struct defid);
967 	defhp->defid_dirclust = dep->de_dirclust;
968 	defhp->defid_dirofs = dep->de_diroffset;
969 	/* defhp->defid_gen = dep->de_gen; */
970 	return (0);
971 }
972 
973 static struct vfsops msdosfs_vfsops = {
974 	msdosfs_mount,
975 	vfs_stdstart,
976 	msdosfs_unmount,
977 	msdosfs_root,
978 	vfs_stdquotactl,
979 	msdosfs_statfs,
980 	msdosfs_sync,
981 	vfs_stdvget,
982 	msdosfs_fhtovp,
983 	msdosfs_checkexp,
984 	msdosfs_vptofh,
985 	msdosfs_init
986 };
987 
988 VFS_SET(msdosfs_vfsops, msdos, 0);
989