xref: /netbsd-src/sys/fs/msdosfs/msdosfs_vfsops.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: msdosfs_vfsops.c,v 1.29 2005/12/11 12:24:25 christos Exp $	*/
2 
3 /*-
4  * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
5  * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
6  * All rights reserved.
7  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by TooLs GmbH.
20  * 4. The name of TooLs GmbH may not be used to endorse or promote products
21  *    derived from this software without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
28  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
29  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
30  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
31  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
32  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  */
34 /*
35  * Written by Paul Popelka (paulp@uts.amdahl.com)
36  *
37  * You can do anything you want with this software, just don't say you wrote
38  * it, and don't remove this notice.
39  *
40  * This software is provided "as is".
41  *
42  * The author supplies this software to be publicly redistributed on the
43  * understanding that the author is not responsible for the correct
44  * functioning of this software in any circumstances and is not liable for
45  * any damages caused by this software.
46  *
47  * October 1992
48  */
49 
50 #include <sys/cdefs.h>
51 __KERNEL_RCSID(0, "$NetBSD: msdosfs_vfsops.c,v 1.29 2005/12/11 12:24:25 christos Exp $");
52 
53 #if defined(_KERNEL_OPT)
54 #include "opt_quota.h"
55 #include "opt_compat_netbsd.h"
56 #endif
57 
58 #include <sys/param.h>
59 #include <sys/systm.h>
60 #include <sys/sysctl.h>
61 #include <sys/namei.h>
62 #include <sys/proc.h>
63 #include <sys/kernel.h>
64 #include <sys/vnode.h>
65 #include <miscfs/specfs/specdev.h> /* XXX */	/* defines v_rdev */
66 #include <sys/mount.h>
67 #include <sys/buf.h>
68 #include <sys/file.h>
69 #include <sys/device.h>
70 #include <sys/disklabel.h>
71 #include <sys/ioctl.h>
72 #include <sys/malloc.h>
73 #include <sys/dirent.h>
74 #include <sys/stat.h>
75 #include <sys/conf.h>
76 
77 #include <fs/msdosfs/bpb.h>
78 #include <fs/msdosfs/bootsect.h>
79 #include <fs/msdosfs/direntry.h>
80 #include <fs/msdosfs/denode.h>
81 #include <fs/msdosfs/msdosfsmount.h>
82 #include <fs/msdosfs/fat.h>
83 
84 #define MSDOSFS_NAMEMAX(pmp) \
85 	(pmp)->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12
86 
87 int msdosfs_mountroot(void);
88 int msdosfs_mount(struct mount *, const char *, void *,
89     struct nameidata *, struct lwp *);
90 int msdosfs_start(struct mount *, int, struct lwp *);
91 int msdosfs_unmount(struct mount *, int, struct lwp *);
92 int msdosfs_root(struct mount *, struct vnode **);
93 int msdosfs_quotactl(struct mount *, int, uid_t, void *, struct lwp *);
94 int msdosfs_statvfs(struct mount *, struct statvfs *, struct lwp *);
95 int msdosfs_sync(struct mount *, int, struct ucred *, struct lwp *);
96 int msdosfs_vget(struct mount *, ino_t, struct vnode **);
97 int msdosfs_fhtovp(struct mount *, struct fid *, struct vnode **);
98 int msdosfs_vptofh(struct vnode *, struct fid *);
99 
100 int msdosfs_mountfs(struct vnode *, struct mount *, struct lwp *,
101     struct msdosfs_args *);
102 
103 static int update_mp(struct mount *, struct msdosfs_args *);
104 
105 MALLOC_DEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOS FS mount structure");
106 MALLOC_DEFINE(M_MSDOSFSFAT, "MSDOSFS fat", "MSDOS FS fat table");
107 
108 #define ROOTNAME "root_device"
109 
110 extern const struct vnodeopv_desc msdosfs_vnodeop_opv_desc;
111 
112 const struct vnodeopv_desc * const msdosfs_vnodeopv_descs[] = {
113 	&msdosfs_vnodeop_opv_desc,
114 	NULL,
115 };
116 
117 struct vfsops msdosfs_vfsops = {
118 	MOUNT_MSDOS,
119 	msdosfs_mount,
120 	msdosfs_start,
121 	msdosfs_unmount,
122 	msdosfs_root,
123 	msdosfs_quotactl,
124 	msdosfs_statvfs,
125 	msdosfs_sync,
126 	msdosfs_vget,
127 	msdosfs_fhtovp,
128 	msdosfs_vptofh,
129 	msdosfs_init,
130 	msdosfs_reinit,
131 	msdosfs_done,
132 	msdosfs_mountroot,
133 	(int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
134 	vfs_stdextattrctl,
135 	msdosfs_vnodeopv_descs,
136 };
137 VFS_ATTACH(msdosfs_vfsops);
138 
139 static int
140 update_mp(mp, argp)
141 	struct mount *mp;
142 	struct msdosfs_args *argp;
143 {
144 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
145 	int error;
146 
147 	pmp->pm_gid = argp->gid;
148 	pmp->pm_uid = argp->uid;
149 	pmp->pm_mask = argp->mask & ALLPERMS;
150 	pmp->pm_dirmask = argp->dirmask & ALLPERMS;
151 	pmp->pm_gmtoff = argp->gmtoff;
152 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
153 
154 	/*
155 	 * GEMDOS knows nothing (yet) about win95
156 	 */
157 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
158 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
159 
160 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
161 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
162 	else if (!(pmp->pm_flags &
163 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
164 		struct vnode *rtvp;
165 
166 		/*
167 		 * Try to divine whether to support Win'95 long filenames
168 		 */
169 		if (FAT32(pmp))
170 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
171 		else {
172 			if ((error = msdosfs_root(mp, &rtvp)) != 0)
173 				return error;
174 			pmp->pm_flags |= findwin95(VTODE(rtvp))
175 				? MSDOSFSMNT_LONGNAME
176 					: MSDOSFSMNT_SHORTNAME;
177 			vput(rtvp);
178 		}
179 	}
180 
181 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
182 
183 	return 0;
184 }
185 
186 int
187 msdosfs_mountroot()
188 {
189 	struct mount *mp;
190 	struct lwp *l = curlwp;	/* XXX */
191 	int error;
192 	struct msdosfs_args args;
193 
194 	if (root_device->dv_class != DV_DISK)
195 		return (ENODEV);
196 
197 	if ((error = vfs_rootmountalloc(MOUNT_MSDOS, "root_device", &mp))) {
198 		vrele(rootvp);
199 		return (error);
200 	}
201 
202 	args.flags = MSDOSFSMNT_VERSIONED;
203 	args.uid = 0;
204 	args.gid = 0;
205 	args.mask = 0777;
206 	args.version = MSDOSFSMNT_VERSION;
207 	args.dirmask = 0777;
208 
209 	if ((error = msdosfs_mountfs(rootvp, mp, l, &args)) != 0) {
210 		mp->mnt_op->vfs_refcount--;
211 		vfs_unbusy(mp);
212 		free(mp, M_MOUNT);
213 		return (error);
214 	}
215 
216 	if ((error = update_mp(mp, &args)) != 0) {
217 		(void)msdosfs_unmount(mp, 0, l);
218 		vfs_unbusy(mp);
219 		free(mp, M_MOUNT);
220 		vrele(rootvp);
221 		return (error);
222 	}
223 
224 	simple_lock(&mountlist_slock);
225 	CIRCLEQ_INSERT_TAIL(&mountlist, mp, mnt_list);
226 	simple_unlock(&mountlist_slock);
227 	(void)msdosfs_statvfs(mp, &mp->mnt_stat, l);
228 	vfs_unbusy(mp);
229 	return (0);
230 }
231 
232 /*
233  * mp - path - addr in user space of mount point (ie /usr or whatever)
234  * data - addr in user space of mount params including the name of the block
235  * special file to treat as a filesystem.
236  */
237 int
238 msdosfs_mount(mp, path, data, ndp, l)
239 	struct mount *mp;
240 	const char *path;
241 	void *data;
242 	struct nameidata *ndp;
243 	struct lwp *l;
244 {
245 	struct vnode *devvp;	  /* vnode for blk device to mount */
246 	struct msdosfs_args args; /* will hold data from mount request */
247 	/* msdosfs specific mount control block */
248 	struct msdosfsmount *pmp = NULL;
249 	struct proc *p;
250 	int error, flags;
251 	mode_t accessmode;
252 
253 	p = l->l_proc;
254 	if (mp->mnt_flag & MNT_GETARGS) {
255 		pmp = VFSTOMSDOSFS(mp);
256 		if (pmp == NULL)
257 			return EIO;
258 		args.fspec = NULL;
259 		args.uid = pmp->pm_uid;
260 		args.gid = pmp->pm_gid;
261 		args.mask = pmp->pm_mask;
262 		args.flags = pmp->pm_flags;
263 		args.version = MSDOSFSMNT_VERSION;
264 		args.dirmask = pmp->pm_dirmask;
265 		args.gmtoff = pmp->pm_gmtoff;
266 		return copyout(&args, data, sizeof(args));
267 	}
268 	error = copyin(data, &args, sizeof(struct msdosfs_args));
269 	if (error)
270 		return (error);
271 
272 	/*
273 	 * If not versioned (i.e. using old mount_msdos(8)), fill in
274 	 * the additional structure items with suitable defaults.
275 	 */
276 	if ((args.flags & MSDOSFSMNT_VERSIONED) == 0) {
277 		args.version = 1;
278 		args.dirmask = args.mask;
279 	}
280 
281 	/*
282 	 * Reset GMT offset for pre-v3 mount structure args.
283 	 */
284 	if (args.version < 3)
285 		args.gmtoff = 0;
286 
287 	/*
288 	 * If updating, check whether changing from read-only to
289 	 * read/write; if there is no device name, that's all we do.
290 	 */
291 	if (mp->mnt_flag & MNT_UPDATE) {
292 		pmp = VFSTOMSDOSFS(mp);
293 		error = 0;
294 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
295 			flags = WRITECLOSE;
296 			if (mp->mnt_flag & MNT_FORCE)
297 				flags |= FORCECLOSE;
298 			error = vflush(mp, NULLVP, flags);
299 		}
300 		if (!error && (mp->mnt_flag & MNT_RELOAD))
301 			/* not yet implemented */
302 			error = EOPNOTSUPP;
303 		if (error)
304 			return (error);
305 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_iflag & IMNT_WANTRDWR)) {
306 			/*
307 			 * If upgrade to read-write by non-root, then verify
308 			 * that user has necessary permissions on the device.
309 			 */
310 			if (p->p_ucred->cr_uid != 0) {
311 				devvp = pmp->pm_devvp;
312 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
313 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
314 						   l->l_proc->p_ucred, l);
315 				VOP_UNLOCK(devvp, 0);
316 				if (error)
317 					return (error);
318 			}
319 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
320 		}
321 		if (args.fspec == NULL)
322 			return EINVAL;
323 	}
324 	/*
325 	 * Not an update, or updating the name: look up the name
326 	 * and verify that it refers to a sensible block device.
327 	 */
328 	NDINIT(ndp, LOOKUP, FOLLOW, UIO_USERSPACE, args.fspec, l);
329 	if ((error = namei(ndp)) != 0)
330 		return (error);
331 	devvp = ndp->ni_vp;
332 
333 	if (devvp->v_type != VBLK) {
334 		vrele(devvp);
335 		return (ENOTBLK);
336 	}
337 	if (bdevsw_lookup(devvp->v_rdev) == NULL) {
338 		vrele(devvp);
339 		return (ENXIO);
340 	}
341 	/*
342 	 * If mount by non-root, then verify that user has necessary
343 	 * permissions on the device.
344 	 */
345 	if (p->p_ucred->cr_uid != 0) {
346 		accessmode = VREAD;
347 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
348 			accessmode |= VWRITE;
349 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
350 		error = VOP_ACCESS(devvp, accessmode, l->l_proc->p_ucred, l);
351 		VOP_UNLOCK(devvp, 0);
352 		if (error) {
353 			vrele(devvp);
354 			return (error);
355 		}
356 	}
357 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
358 		int xflags;
359 
360 		/*
361 		 * Disallow multiple mounts of the same device.
362 		 * Disallow mounting of a device that is currently in use
363 		 * (except for root, which might share swap device for
364 		 * miniroot).
365 		 */
366 		error = vfs_mountedon(devvp);
367 		if (error)
368 			goto fail;
369 		if (vcount(devvp) > 1 && devvp != rootvp) {
370 			error = EBUSY;
371 			goto fail;
372 		}
373 		if (mp->mnt_flag & MNT_RDONLY)
374 			xflags = FREAD;
375 		else
376 			xflags = FREAD|FWRITE;
377 		error = VOP_OPEN(devvp, xflags, FSCRED, l);
378 		if (error)
379 			goto fail;
380 		error = msdosfs_mountfs(devvp, mp, l, &args);
381 		if (error) {
382 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
383 			(void) VOP_CLOSE(devvp, xflags, NOCRED, l);
384 			VOP_UNLOCK(devvp, 0);
385 			goto fail;
386 		}
387 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
388 		pmp = VFSTOMSDOSFS(mp);
389 #endif
390 	} else {
391 		vrele(devvp);
392 		if (devvp != pmp->pm_devvp)
393 			return (EINVAL);	/* needs translation */
394 	}
395 	if ((error = update_mp(mp, &args)) != 0) {
396 		msdosfs_unmount(mp, MNT_FORCE, l);
397 		return error;
398 	}
399 
400 #ifdef MSDOSFS_DEBUG
401 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
402 #endif
403 	return set_statvfs_info(path, UIO_USERSPACE, args.fspec, UIO_USERSPACE,
404 	    mp, l);
405 
406 fail:
407 	vrele(devvp);
408 	return (error);
409 }
410 
411 int
412 msdosfs_mountfs(devvp, mp, l, argp)
413 	struct vnode *devvp;
414 	struct mount *mp;
415 	struct lwp *l;
416 	struct msdosfs_args *argp;
417 {
418 	struct msdosfsmount *pmp;
419 	struct buf *bp;
420 	dev_t dev = devvp->v_rdev;
421 	struct partinfo dpart;
422 	union bootsector *bsp;
423 	struct byte_bpb33 *b33;
424 	struct byte_bpb50 *b50;
425 	struct byte_bpb710 *b710;
426 	u_int8_t SecPerClust;
427 	int	ronly, error;
428 	int	bsize = 0, dtype = 0, tmp;
429 
430 	/* Flush out any old buffers remaining from a previous use. */
431 	if ((error = vinvalbuf(devvp, V_SAVE, l->l_proc->p_ucred, l, 0, 0)) != 0)
432 		return (error);
433 
434 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
435 
436 	bp  = NULL; /* both used in error_exit */
437 	pmp = NULL;
438 
439 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
440 		/*
441 	 	 * We need the disklabel to calculate the size of a FAT entry
442 		 * later on. Also make sure the partition contains a filesystem
443 		 * of type FS_MSDOS. This doesn't work for floppies, so we have
444 		 * to check for them too.
445 	 	 *
446 	 	 * At least some parts of the msdos fs driver seem to assume
447 		 * that the size of a disk block will always be 512 bytes.
448 		 * Let's check it...
449 		 */
450 		error = VOP_IOCTL(devvp, DIOCGPART, &dpart, FREAD, NOCRED, l);
451 		if (error)
452 			goto error_exit;
453 		tmp   = dpart.part->p_fstype;
454 		dtype = dpart.disklab->d_type;
455 		bsize = dpart.disklab->d_secsize;
456 		if (bsize != 512 || (dtype!=DTYPE_FLOPPY && tmp!=FS_MSDOS)) {
457 			error = EINVAL;
458 			goto error_exit;
459 		}
460 	}
461 
462 	/*
463 	 * Read the boot sector of the filesystem, and then check the
464 	 * boot signature.  If not a dos boot sector then error out.
465 	 */
466 	if ((error = bread(devvp, 0, 512, NOCRED, &bp)) != 0)
467 		goto error_exit;
468 	bp->b_flags |= B_AGE;
469 	bsp = (union bootsector *)bp->b_data;
470 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
471 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
472 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
473 
474 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
475 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
476 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
477 			error = EINVAL;
478 			goto error_exit;
479 		}
480 	}
481 
482 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK);
483 	memset(pmp, 0, sizeof *pmp);
484 	pmp->pm_mountp = mp;
485 
486 	/*
487 	 * Compute several useful quantities from the bpb in the
488 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
489 	 * the fields that are different between dos 5 and dos 3.3.
490 	 */
491 	SecPerClust = b50->bpbSecPerClust;
492 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
493 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
494 	pmp->pm_FATs = b50->bpbFATs;
495 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
496 	pmp->pm_Sectors = getushort(b50->bpbSectors);
497 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
498 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
499 	pmp->pm_Heads = getushort(b50->bpbHeads);
500 	pmp->pm_Media = b50->bpbMedia;
501 
502 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
503 		/* XXX - We should probably check more values here */
504     		if (!pmp->pm_BytesPerSec || !SecPerClust
505 	    		|| pmp->pm_Heads > 255 || pmp->pm_SecPerTrack > 63) {
506 			error = EINVAL;
507 			goto error_exit;
508 		}
509 	}
510 
511 	if (pmp->pm_Sectors == 0) {
512 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
513 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
514 	} else {
515 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
516 		pmp->pm_HugeSectors = pmp->pm_Sectors;
517 	}
518 
519 	if (pmp->pm_RootDirEnts == 0) {
520 		if (bsp->bs710.bsBootSectSig2 != BOOTSIG2
521 		    || bsp->bs710.bsBootSectSig3 != BOOTSIG3
522 		    || pmp->pm_Sectors
523 		    || pmp->pm_FATsecs
524 		    || getushort(b710->bpbFSVers)) {
525 			error = EINVAL;
526 			goto error_exit;
527 		}
528 		pmp->pm_fatmask = FAT32_MASK;
529 		pmp->pm_fatmult = 4;
530 		pmp->pm_fatdiv = 1;
531 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
532 
533 		/* mirrorring is enabled if the FATMIRROR bit is not set */
534 		if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
535 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
536 		else
537 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
538 	} else
539 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
540 
541 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
542 		if (FAT32(pmp)) {
543 			/*
544 			 * GEMDOS doesn't know fat32.
545 			 */
546 			error = EINVAL;
547 			goto error_exit;
548 		}
549 
550 		/*
551 		 * Check a few values (could do some more):
552 		 * - logical sector size: power of 2, >= block size
553 		 * - sectors per cluster: power of 2, >= 1
554 		 * - number of sectors:   >= 1, <= size of partition
555 		 */
556 		if ( (SecPerClust == 0)
557 		  || (SecPerClust & (SecPerClust - 1))
558 		  || (pmp->pm_BytesPerSec < bsize)
559 		  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
560 		  || (pmp->pm_HugeSectors == 0)
561 		  || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize)
562 							> dpart.part->p_size)
563 		   ) {
564 			error = EINVAL;
565 			goto error_exit;
566 		}
567 		/*
568 		 * XXX - Many parts of the msdos fs driver seem to assume that
569 		 * the number of bytes per logical sector (BytesPerSec) will
570 		 * always be the same as the number of bytes per disk block
571 		 * Let's pretend it is.
572 		 */
573 		tmp = pmp->pm_BytesPerSec / bsize;
574 		pmp->pm_BytesPerSec  = bsize;
575 		pmp->pm_HugeSectors *= tmp;
576 		pmp->pm_HiddenSects *= tmp;
577 		pmp->pm_ResSectors  *= tmp;
578 		pmp->pm_Sectors     *= tmp;
579 		pmp->pm_FATsecs     *= tmp;
580 		SecPerClust         *= tmp;
581 	}
582 	pmp->pm_fatblk = pmp->pm_ResSectors;
583 	if (FAT32(pmp)) {
584 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
585 		pmp->pm_firstcluster = pmp->pm_fatblk
586 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
587 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
588 	} else {
589 		pmp->pm_rootdirblk = pmp->pm_fatblk +
590 			(pmp->pm_FATs * pmp->pm_FATsecs);
591 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
592 				       + pmp->pm_BytesPerSec - 1)
593 			/ pmp->pm_BytesPerSec;/* in sectors */
594 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
595 	}
596 
597 	pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
598 	    SecPerClust;
599 	pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
600 	pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
601 
602 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
603 		if (pmp->pm_nmbrofclusters <= (0xff0 - 2)
604 		      && (dtype == DTYPE_FLOPPY
605 			  || (dtype == DTYPE_VND
606 				&& (pmp->pm_Heads == 1 || pmp->pm_Heads == 2)))
607 		    ) {
608 			pmp->pm_fatmask = FAT12_MASK;
609 			pmp->pm_fatmult = 3;
610 			pmp->pm_fatdiv = 2;
611 		} else {
612 			pmp->pm_fatmask = FAT16_MASK;
613 			pmp->pm_fatmult = 2;
614 			pmp->pm_fatdiv = 1;
615 		}
616 	} else if (pmp->pm_fatmask == 0) {
617 		if (pmp->pm_maxcluster
618 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
619 			/*
620 			 * This will usually be a floppy disk. This size makes
621 			 * sure that one fat entry will not be split across
622 			 * multiple blocks.
623 			 */
624 			pmp->pm_fatmask = FAT12_MASK;
625 			pmp->pm_fatmult = 3;
626 			pmp->pm_fatdiv = 2;
627 		} else {
628 			pmp->pm_fatmask = FAT16_MASK;
629 			pmp->pm_fatmult = 2;
630 			pmp->pm_fatdiv = 1;
631 		}
632 	}
633 	if (FAT12(pmp))
634 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
635 	else
636 		pmp->pm_fatblocksize = MAXBSIZE;
637 
638 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
639 	pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
640 
641 	/*
642 	 * Compute mask and shift value for isolating cluster relative byte
643 	 * offsets and cluster numbers from a file offset.
644 	 */
645 	pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
646 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
647 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
648 
649 	/*
650 	 * Check for valid cluster size
651 	 * must be a power of 2
652 	 */
653 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
654 		error = EINVAL;
655 		goto error_exit;
656 	}
657 
658 	/*
659 	 * Release the bootsector buffer.
660 	 */
661 	brelse(bp);
662 	bp = NULL;
663 
664 	/*
665 	 * Check FSInfo.
666 	 */
667 	if (pmp->pm_fsinfo) {
668 		struct fsinfo *fp;
669 
670 		if ((error = bread(devvp, pmp->pm_fsinfo, 1024, NOCRED, &bp)) != 0)
671 			goto error_exit;
672 		fp = (struct fsinfo *)bp->b_data;
673 		if (!memcmp(fp->fsisig1, "RRaA", 4)
674 		    && !memcmp(fp->fsisig2, "rrAa", 4)
675 		    && !memcmp(fp->fsisig3, "\0\0\125\252", 4)
676 		    && !memcmp(fp->fsisig4, "\0\0\125\252", 4))
677 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
678 		else
679 			pmp->pm_fsinfo = 0;
680 		brelse(bp);
681 		bp = NULL;
682 	}
683 
684 	/*
685 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
686 	 * XXX
687 	 */
688 	if (pmp->pm_fsinfo) {
689 		if (pmp->pm_nxtfree == (u_long)-1)
690 			pmp->pm_fsinfo = 0;
691 	}
692 
693 	/*
694 	 * Allocate memory for the bitmap of allocated clusters, and then
695 	 * fill it in.
696 	 */
697 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
698 				   / N_INUSEBITS)
699 				  * sizeof(*pmp->pm_inusemap),
700 				  M_MSDOSFSFAT, M_WAITOK);
701 
702 	/*
703 	 * fillinusemap() needs pm_devvp.
704 	 */
705 	pmp->pm_dev = dev;
706 	pmp->pm_devvp = devvp;
707 
708 	/*
709 	 * Have the inuse map filled in.
710 	 */
711 	if ((error = fillinusemap(pmp)) != 0)
712 		goto error_exit;
713 
714 	/*
715 	 * If they want fat updates to be synchronous then let them suffer
716 	 * the performance degradation in exchange for the on disk copy of
717 	 * the fat being correct just about all the time.  I suppose this
718 	 * would be a good thing to turn on if the kernel is still flakey.
719 	 */
720 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
721 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
722 
723 	/*
724 	 * Finish up.
725 	 */
726 	if (ronly)
727 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
728 	else
729 		pmp->pm_fmod = 1;
730 	mp->mnt_data = pmp;
731 	mp->mnt_stat.f_fsidx.__fsid_val[0] = (long)dev;
732 	mp->mnt_stat.f_fsidx.__fsid_val[1] = makefstype(MOUNT_MSDOS);
733 	mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
734 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
735 	mp->mnt_flag |= MNT_LOCAL;
736 	mp->mnt_dev_bshift = pmp->pm_bnshift;
737 	mp->mnt_fs_bshift = pmp->pm_cnshift;
738 
739 #ifdef QUOTA
740 	/*
741 	 * If we ever do quotas for DOS filesystems this would be a place
742 	 * to fill in the info in the msdosfsmount structure. You dolt,
743 	 * quotas on dos filesystems make no sense because files have no
744 	 * owners on dos filesystems. of course there is some empty space
745 	 * in the directory entry where we could put uid's and gid's.
746 	 */
747 #endif
748 	devvp->v_specmountpoint = mp;
749 
750 	return (0);
751 
752 error_exit:;
753 	if (bp)
754 		brelse(bp);
755 	if (pmp) {
756 		if (pmp->pm_inusemap)
757 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
758 		free(pmp, M_MSDOSFSMNT);
759 		mp->mnt_data = NULL;
760 	}
761 	return (error);
762 }
763 
764 int
765 msdosfs_start(mp, flags, l)
766 	struct mount *mp;
767 	int flags;
768 	struct lwp *l;
769 {
770 
771 	return (0);
772 }
773 
774 /*
775  * Unmount the filesystem described by mp.
776  */
777 int
778 msdosfs_unmount(mp, mntflags, l)
779 	struct mount *mp;
780 	int mntflags;
781 	struct lwp *l;
782 {
783 	struct msdosfsmount *pmp;
784 	int error, flags;
785 
786 	flags = 0;
787 	if (mntflags & MNT_FORCE)
788 		flags |= FORCECLOSE;
789 #ifdef QUOTA
790 #endif
791 	if ((error = vflush(mp, NULLVP, flags)) != 0)
792 		return (error);
793 	pmp = VFSTOMSDOSFS(mp);
794 	if (pmp->pm_devvp->v_type != VBAD)
795 		pmp->pm_devvp->v_specmountpoint = NULL;
796 #ifdef MSDOSFS_DEBUG
797 	{
798 		struct vnode *vp = pmp->pm_devvp;
799 
800 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
801 		printf("flag %08x, usecount %d, writecount %ld, holdcnt %ld\n",
802 		    vp->v_flag, vp->v_usecount, vp->v_writecount, vp->v_holdcnt);
803 		printf("mount %p, op %p\n",
804 		    vp->v_mount, vp->v_op);
805 		printf("freef %p, freeb %p, mount %p\n",
806 		    vp->v_freelist.tqe_next, vp->v_freelist.tqe_prev,
807 		    vp->v_mount);
808 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %d, type %d\n",
809 		    vp->v_cleanblkhd.lh_first,
810 		    vp->v_dirtyblkhd.lh_first,
811 		    vp->v_numoutput, vp->v_type);
812 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
813 		    vp->v_socket, vp->v_tag,
814 		    ((u_int *)vp->v_data)[0],
815 		    ((u_int *)vp->v_data)[1]);
816 	}
817 #endif
818 	vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
819 	error = VOP_CLOSE(pmp->pm_devvp,
820 	    pmp->pm_flags & MSDOSFSMNT_RONLY ? FREAD : FREAD|FWRITE, NOCRED, l);
821 	vput(pmp->pm_devvp);
822 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
823 	free(pmp, M_MSDOSFSMNT);
824 	mp->mnt_data = NULL;
825 	mp->mnt_flag &= ~MNT_LOCAL;
826 	return (error);
827 }
828 
829 int
830 msdosfs_root(mp, vpp)
831 	struct mount *mp;
832 	struct vnode **vpp;
833 {
834 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
835 	struct denode *ndep;
836 	int error;
837 
838 #ifdef MSDOSFS_DEBUG
839 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
840 #endif
841 	if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0)
842 		return (error);
843 	*vpp = DETOV(ndep);
844 	return (0);
845 }
846 
847 int
848 msdosfs_quotactl(mp, cmds, uid, arg, l)
849 	struct mount *mp;
850 	int cmds;
851 	uid_t uid;
852 	void *arg;
853 	struct lwp *l;
854 {
855 
856 #ifdef QUOTA
857 	return (EOPNOTSUPP);
858 #else
859 	return (EOPNOTSUPP);
860 #endif
861 }
862 
863 int
864 msdosfs_statvfs(mp, sbp, l)
865 	struct mount *mp;
866 	struct statvfs *sbp;
867 	struct lwp *l;
868 {
869 	struct msdosfsmount *pmp;
870 
871 	pmp = VFSTOMSDOSFS(mp);
872 	sbp->f_bsize = pmp->pm_bpcluster;
873 	sbp->f_frsize = sbp->f_bsize;
874 	sbp->f_iosize = pmp->pm_bpcluster;
875 	sbp->f_blocks = pmp->pm_nmbrofclusters;
876 	sbp->f_bfree = pmp->pm_freeclustercount;
877 	sbp->f_bavail = pmp->pm_freeclustercount;
878 	sbp->f_bresvd = 0;
879 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
880 	sbp->f_ffree = 0;	/* what to put in here? */
881 	sbp->f_favail = 0;	/* what to put in here? */
882 	sbp->f_fresvd = 0;
883 	copy_statvfs_info(sbp, mp);
884 	return (0);
885 }
886 
887 int
888 msdosfs_sync(mp, waitfor, cred, l)
889 	struct mount *mp;
890 	int waitfor;
891 	struct ucred *cred;
892 	struct lwp *l;
893 {
894 	struct vnode *vp, *nvp;
895 	struct denode *dep;
896 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
897 	int error, allerror = 0;
898 
899 	/*
900 	 * If we ever switch to not updating all of the fats all the time,
901 	 * this would be the place to update them from the first one.
902 	 */
903 	if (pmp->pm_fmod != 0) {
904 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
905 			panic("msdosfs_sync: rofs mod");
906 		else {
907 			/* update fats here */
908 		}
909 	}
910 	/*
911 	 * Write back each (modified) denode.
912 	 */
913 	simple_lock(&mntvnode_slock);
914 loop:
915 	for (vp = mp->mnt_vnodelist.lh_first; vp != NULL; vp = nvp) {
916 		/*
917 		 * If the vnode that we are about to sync is no longer
918 		 * assoicated with this mount point, start over.
919 		 */
920 		if (vp->v_mount != mp)
921 			goto loop;
922 		simple_lock(&vp->v_interlock);
923 		nvp = vp->v_mntvnodes.le_next;
924 		dep = VTODE(vp);
925 		if (waitfor == MNT_LAZY || vp->v_type == VNON ||
926 		    (((dep->de_flag &
927 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0) &&
928 		     (LIST_EMPTY(&vp->v_dirtyblkhd) &&
929 		      vp->v_uobj.uo_npages == 0))) {
930 			simple_unlock(&vp->v_interlock);
931 			continue;
932 		}
933 		simple_unlock(&mntvnode_slock);
934 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK);
935 		if (error) {
936 			simple_lock(&mntvnode_slock);
937 			if (error == ENOENT)
938 				goto loop;
939 			continue;
940 		}
941 		if ((error = VOP_FSYNC(vp, cred,
942 		    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0, l)) != 0)
943 			allerror = error;
944 		vput(vp);
945 		simple_lock(&mntvnode_slock);
946 	}
947 	simple_unlock(&mntvnode_slock);
948 	/*
949 	 * Force stale file system control information to be flushed.
950 	 */
951 	if ((error = VOP_FSYNC(pmp->pm_devvp, cred,
952 	    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0, l)) != 0)
953 		allerror = error;
954 #ifdef QUOTA
955 	/* qsync(mp); */
956 #endif
957 	return (allerror);
958 }
959 
960 int
961 msdosfs_fhtovp(mp, fhp, vpp)
962 	struct mount *mp;
963 	struct fid *fhp;
964 	struct vnode **vpp;
965 {
966 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
967 	struct defid *defhp = (struct defid *) fhp;
968 	struct denode *dep;
969 	int error;
970 
971 	error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
972 	if (error) {
973 		*vpp = NULLVP;
974 		return (error);
975 	}
976 	*vpp = DETOV(dep);
977 	return (0);
978 }
979 
980 int
981 msdosfs_vptofh(vp, fhp)
982 	struct vnode *vp;
983 	struct fid *fhp;
984 {
985 	struct denode *dep;
986 	struct defid *defhp;
987 
988 	dep = VTODE(vp);
989 	defhp = (struct defid *)fhp;
990 	defhp->defid_len = sizeof(struct defid);
991 	defhp->defid_dirclust = dep->de_dirclust;
992 	defhp->defid_dirofs = dep->de_diroffset;
993 	/* defhp->defid_gen = dep->de_gen; */
994 	return (0);
995 }
996 
997 int
998 msdosfs_vget(mp, ino, vpp)
999 	struct mount *mp;
1000 	ino_t ino;
1001 	struct vnode **vpp;
1002 {
1003 
1004 	return (EOPNOTSUPP);
1005 }
1006 
1007 SYSCTL_SETUP(sysctl_vfs_msdosfs_setup, "sysctl vfs.msdosfs subtree setup")
1008 {
1009 
1010 	sysctl_createv(clog, 0, NULL, NULL,
1011 		       CTLFLAG_PERMANENT,
1012 		       CTLTYPE_NODE, "vfs", NULL,
1013 		       NULL, 0, NULL, 0,
1014 		       CTL_VFS, CTL_EOL);
1015 	sysctl_createv(clog, 0, NULL, NULL,
1016 		       CTLFLAG_PERMANENT,
1017 		       CTLTYPE_NODE, "msdosfs",
1018 		       SYSCTL_DESCR("MS-DOS file system"),
1019 		       NULL, 0, NULL, 0,
1020 		       CTL_VFS, 4, CTL_EOL);
1021 	/*
1022 	 * XXX the "4" above could be dynamic, thereby eliminating one
1023 	 * more instance of the "number to vfs" mapping problem, but
1024 	 * "4" is the order as taken from sys/mount.h
1025 	 */
1026 }
1027