xref: /netbsd-src/sys/fs/msdosfs/msdosfs_vfsops.c (revision 274254cdae52594c1aa480a736aef78313d15c9c)
1 /*	$NetBSD: msdosfs_vfsops.c,v 1.73 2009/03/15 17:15:57 cegger 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 1.73 2009/03/15 17:15:57 cegger Exp $");
52 
53 #if defined(_KERNEL_OPT)
54 #include "opt_compat_netbsd.h"
55 #endif
56 
57 #include <sys/param.h>
58 #include <sys/systm.h>
59 #include <sys/sysctl.h>
60 #include <sys/namei.h>
61 #include <sys/proc.h>
62 #include <sys/kernel.h>
63 #include <sys/vnode.h>
64 #include <miscfs/genfs/genfs.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/disk.h>
72 #include <sys/ioctl.h>
73 #include <sys/malloc.h>
74 #include <sys/dirent.h>
75 #include <sys/stat.h>
76 #include <sys/conf.h>
77 #include <sys/kauth.h>
78 #include <sys/module.h>
79 
80 #include <fs/msdosfs/bpb.h>
81 #include <fs/msdosfs/bootsect.h>
82 #include <fs/msdosfs/direntry.h>
83 #include <fs/msdosfs/denode.h>
84 #include <fs/msdosfs/msdosfsmount.h>
85 #include <fs/msdosfs/fat.h>
86 
87 MODULE(MODULE_CLASS_VFS, msdosfs, NULL);
88 
89 #ifdef MSDOSFS_DEBUG
90 #define DPRINTF(a) uprintf a
91 #else
92 #define DPRINTF(a)
93 #endif
94 
95 #define MSDOSFS_NAMEMAX(pmp) \
96 	(pmp)->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12
97 
98 VFS_PROTOS(msdosfs);
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_JUSTDEFINE(M_MSDOSFSMNT, "MSDOSFS mount", "MSDOS FS mount structure");
106 MALLOC_JUSTDEFINE(M_MSDOSFSFAT, "MSDOSFS fat", "MSDOS FS fat table");
107 MALLOC_JUSTDEFINE(M_MSDOSFSTMP, "MSDOSFS temp", "MSDOS FS temp. structures");
108 
109 #define ROOTNAME "root_device"
110 
111 static struct sysctllog *msdosfs_sysctl_log;
112 
113 extern const struct vnodeopv_desc msdosfs_vnodeop_opv_desc;
114 
115 const struct vnodeopv_desc * const msdosfs_vnodeopv_descs[] = {
116 	&msdosfs_vnodeop_opv_desc,
117 	NULL,
118 };
119 
120 struct vfsops msdosfs_vfsops = {
121 	MOUNT_MSDOS,
122 	sizeof (struct msdosfs_args),
123 	msdosfs_mount,
124 	msdosfs_start,
125 	msdosfs_unmount,
126 	msdosfs_root,
127 	(void *)eopnotsupp,		/* vfs_quotactl */
128 	msdosfs_statvfs,
129 	msdosfs_sync,
130 	msdosfs_vget,
131 	msdosfs_fhtovp,
132 	msdosfs_vptofh,
133 	msdosfs_init,
134 	msdosfs_reinit,
135 	msdosfs_done,
136 	msdosfs_mountroot,
137 	(int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
138 	vfs_stdextattrctl,
139 	(void *)eopnotsupp,		/* vfs_suspendctl */
140 	genfs_renamelock_enter,
141 	genfs_renamelock_exit,
142 	(void *)eopnotsupp,
143 	msdosfs_vnodeopv_descs,
144 	0,
145 	{ NULL, NULL },
146 };
147 
148 static int
149 msdosfs_modcmd(modcmd_t cmd, void *arg)
150 {
151 	int error;
152 
153 	switch (cmd) {
154 	case MODULE_CMD_INIT:
155 		error = vfs_attach(&msdosfs_vfsops);
156 		if (error != 0)
157 			break;
158 		sysctl_createv(&msdosfs_sysctl_log, 0, NULL, NULL,
159 			       CTLFLAG_PERMANENT,
160 			       CTLTYPE_NODE, "vfs", NULL,
161 			       NULL, 0, NULL, 0,
162 			       CTL_VFS, CTL_EOL);
163 		sysctl_createv(&msdosfs_sysctl_log, 0, NULL, NULL,
164 			       CTLFLAG_PERMANENT,
165 			       CTLTYPE_NODE, "msdosfs",
166 			       SYSCTL_DESCR("MS-DOS file system"),
167 			       NULL, 0, NULL, 0,
168 			       CTL_VFS, 4, CTL_EOL);
169 		/*
170 		 * XXX the "4" above could be dynamic, thereby eliminating one
171 		 * more instance of the "number to vfs" mapping problem, but
172 		 * "4" is the order as taken from sys/mount.h
173 		 */
174 		break;
175 	case MODULE_CMD_FINI:
176 		error = vfs_detach(&msdosfs_vfsops);
177 		if (error != 0)
178 			break;
179 		sysctl_teardown(&msdosfs_sysctl_log);
180 		break;
181 	default:
182 		error = ENOTTY;
183 		break;
184 	}
185 
186 	return (error);
187 }
188 
189 static int
190 update_mp(struct mount *mp, struct msdosfs_args *argp)
191 {
192 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
193 	int error;
194 
195 	pmp->pm_gid = argp->gid;
196 	pmp->pm_uid = argp->uid;
197 	pmp->pm_mask = argp->mask & ALLPERMS;
198 	pmp->pm_dirmask = argp->dirmask & ALLPERMS;
199 	pmp->pm_gmtoff = argp->gmtoff;
200 	pmp->pm_flags |= argp->flags & MSDOSFSMNT_MNTOPT;
201 
202 	/*
203 	 * GEMDOS knows nothing about win95 long filenames
204 	 */
205 	if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
206 		pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
207 
208 	if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
209 		pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
210 	else if (!(pmp->pm_flags &
211 	    (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
212 		struct vnode *rtvp;
213 
214 		/*
215 		 * Try to divine whether to support Win'95 long filenames
216 		 */
217 		if (FAT32(pmp))
218 			pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
219 		else {
220 			if ((error = msdosfs_root(mp, &rtvp)) != 0)
221 				return error;
222 			pmp->pm_flags |= findwin95(VTODE(rtvp))
223 				? MSDOSFSMNT_LONGNAME
224 					: MSDOSFSMNT_SHORTNAME;
225 			vput(rtvp);
226 		}
227 	}
228 
229 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
230 
231 	return 0;
232 }
233 
234 int
235 msdosfs_mountroot(void)
236 {
237 	struct mount *mp;
238 	struct lwp *l = curlwp;	/* XXX */
239 	int error;
240 	struct msdosfs_args args;
241 
242 	if (device_class(root_device) != DV_DISK)
243 		return (ENODEV);
244 
245 	if ((error = vfs_rootmountalloc(MOUNT_MSDOS, "root_device", &mp))) {
246 		vrele(rootvp);
247 		return (error);
248 	}
249 
250 	args.flags = MSDOSFSMNT_VERSIONED;
251 	args.uid = 0;
252 	args.gid = 0;
253 	args.mask = 0777;
254 	args.version = MSDOSFSMNT_VERSION;
255 	args.dirmask = 0777;
256 
257 	if ((error = msdosfs_mountfs(rootvp, mp, l, &args)) != 0) {
258 		vfs_unbusy(mp, false, NULL);
259 		vfs_destroy(mp);
260 		return (error);
261 	}
262 
263 	if ((error = update_mp(mp, &args)) != 0) {
264 		(void)msdosfs_unmount(mp, 0);
265 		vfs_unbusy(mp, false, NULL);
266 		vfs_destroy(mp);
267 		vrele(rootvp);
268 		return (error);
269 	}
270 
271 	mutex_enter(&mountlist_lock);
272 	CIRCLEQ_INSERT_TAIL(&mountlist, mp, mnt_list);
273 	mutex_exit(&mountlist_lock);
274 	(void)msdosfs_statvfs(mp, &mp->mnt_stat);
275 	vfs_unbusy(mp, false, NULL);
276 	return (0);
277 }
278 
279 /*
280  * mp - path - addr in user space of mount point (ie /usr or whatever)
281  * data - addr in user space of mount params including the name of the block
282  * special file to treat as a filesystem.
283  */
284 int
285 msdosfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
286 {
287 	struct lwp *l = curlwp;
288 	struct nameidata nd;
289 	struct vnode *devvp;	  /* vnode for blk device to mount */
290 	struct msdosfs_args *args = data; /* holds data from mount request */
291 	/* msdosfs specific mount control block */
292 	struct msdosfsmount *pmp = NULL;
293 	int error, flags;
294 	mode_t accessmode;
295 
296 	if (*data_len < sizeof *args)
297 		return EINVAL;
298 
299 	if (mp->mnt_flag & MNT_GETARGS) {
300 		pmp = VFSTOMSDOSFS(mp);
301 		if (pmp == NULL)
302 			return EIO;
303 		args->fspec = NULL;
304 		args->uid = pmp->pm_uid;
305 		args->gid = pmp->pm_gid;
306 		args->mask = pmp->pm_mask;
307 		args->flags = pmp->pm_flags;
308 		args->version = MSDOSFSMNT_VERSION;
309 		args->dirmask = pmp->pm_dirmask;
310 		args->gmtoff = pmp->pm_gmtoff;
311 		*data_len = sizeof *args;
312 		return 0;
313 	}
314 
315 	/*
316 	 * If not versioned (i.e. using old mount_msdos(8)), fill in
317 	 * the additional structure items with suitable defaults.
318 	 */
319 	if ((args->flags & MSDOSFSMNT_VERSIONED) == 0) {
320 		args->version = 1;
321 		args->dirmask = args->mask;
322 	}
323 
324 	/*
325 	 * Reset GMT offset for pre-v3 mount structure args.
326 	 */
327 	if (args->version < 3)
328 		args->gmtoff = 0;
329 
330 	/*
331 	 * If updating, check whether changing from read-only to
332 	 * read/write; if there is no device name, that's all we do.
333 	 */
334 	if (mp->mnt_flag & MNT_UPDATE) {
335 		pmp = VFSTOMSDOSFS(mp);
336 		error = 0;
337 		if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_flag & MNT_RDONLY)) {
338 			flags = WRITECLOSE;
339 			if (mp->mnt_flag & MNT_FORCE)
340 				flags |= FORCECLOSE;
341 			error = vflush(mp, NULLVP, flags);
342 		}
343 		if (!error && (mp->mnt_flag & MNT_RELOAD))
344 			/* not yet implemented */
345 			error = EOPNOTSUPP;
346 		if (error) {
347 			DPRINTF(("vflush %d\n", error));
348 			return (error);
349 		}
350 		if ((pmp->pm_flags & MSDOSFSMNT_RONLY) && (mp->mnt_iflag & IMNT_WANTRDWR)) {
351 			/*
352 			 * If upgrade to read-write by non-root, then verify
353 			 * that user has necessary permissions on the device.
354 			 */
355 			if (kauth_authorize_generic(l->l_cred,
356 			    KAUTH_GENERIC_ISSUSER, NULL) != 0) {
357 				devvp = pmp->pm_devvp;
358 				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
359 				error = VOP_ACCESS(devvp, VREAD | VWRITE,
360 						   l->l_cred);
361 				VOP_UNLOCK(devvp, 0);
362 				DPRINTF(("VOP_ACCESS %d\n", error));
363 				if (error)
364 					return (error);
365 			}
366 			pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
367 		}
368 		if (args->fspec == NULL) {
369 			DPRINTF(("missing fspec\n"));
370 			return EINVAL;
371 		}
372 	}
373 	/*
374 	 * Not an update, or updating the name: look up the name
375 	 * and verify that it refers to a sensible block device.
376 	 */
377 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, args->fspec);
378 	if ((error = namei(&nd)) != 0) {
379 		DPRINTF(("namei %d\n", error));
380 		return (error);
381 	}
382 	devvp = nd.ni_vp;
383 
384 	if (devvp->v_type != VBLK) {
385 		DPRINTF(("not block\n"));
386 		vrele(devvp);
387 		return (ENOTBLK);
388 	}
389 	if (bdevsw_lookup(devvp->v_rdev) == NULL) {
390 		DPRINTF(("no block switch\n"));
391 		vrele(devvp);
392 		return (ENXIO);
393 	}
394 	/*
395 	 * If mount by non-root, then verify that user has necessary
396 	 * permissions on the device.
397 	 */
398 	if (kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER, NULL) != 0) {
399 		accessmode = VREAD;
400 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
401 			accessmode |= VWRITE;
402 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
403 		error = VOP_ACCESS(devvp, accessmode, l->l_cred);
404 		VOP_UNLOCK(devvp, 0);
405 		if (error) {
406 			DPRINTF(("VOP_ACCESS2 %d\n", error));
407 			vrele(devvp);
408 			return (error);
409 		}
410 	}
411 	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
412 		int xflags;
413 
414 		if (mp->mnt_flag & MNT_RDONLY)
415 			xflags = FREAD;
416 		else
417 			xflags = FREAD|FWRITE;
418 		error = VOP_OPEN(devvp, xflags, FSCRED);
419 		if (error) {
420 			DPRINTF(("VOP_OPEN %d\n", error));
421 			goto fail;
422 		}
423 		error = msdosfs_mountfs(devvp, mp, l, args);
424 		if (error) {
425 			DPRINTF(("msdosfs_mountfs %d\n", error));
426 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
427 			(void) VOP_CLOSE(devvp, xflags, NOCRED);
428 			VOP_UNLOCK(devvp, 0);
429 			goto fail;
430 		}
431 #ifdef MSDOSFS_DEBUG		/* only needed for the printf below */
432 		pmp = VFSTOMSDOSFS(mp);
433 #endif
434 	} else {
435 		vrele(devvp);
436 		if (devvp != pmp->pm_devvp) {
437 			DPRINTF(("devvp %p pmp %p\n",
438 			    devvp, pmp->pm_devvp));
439 			return (EINVAL);	/* needs translation */
440 		}
441 	}
442 	if ((error = update_mp(mp, args)) != 0) {
443 		msdosfs_unmount(mp, MNT_FORCE);
444 		DPRINTF(("update_mp %d\n", error));
445 		return error;
446 	}
447 
448 #ifdef MSDOSFS_DEBUG
449 	printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
450 #endif
451 	return set_statvfs_info(path, UIO_USERSPACE, args->fspec, UIO_USERSPACE,
452 	    mp->mnt_op->vfs_name, mp, l);
453 
454 fail:
455 	vrele(devvp);
456 	return (error);
457 }
458 
459 int
460 msdosfs_mountfs(struct vnode *devvp, struct mount *mp, struct lwp *l, struct msdosfs_args *argp)
461 {
462 	struct msdosfsmount *pmp;
463 	struct buf *bp;
464 	dev_t dev = devvp->v_rdev;
465 	struct partinfo dpart;
466 	union bootsector *bsp;
467 	struct byte_bpb33 *b33;
468 	struct byte_bpb50 *b50;
469 	struct byte_bpb710 *b710;
470 	u_int8_t SecPerClust;
471 	int	ronly, error, tmp;
472 	int	bsize, dtype, fstype, secsize;
473 	u_int64_t psize;
474 
475 	/* Flush out any old buffers remaining from a previous use. */
476 	if ((error = vinvalbuf(devvp, V_SAVE, l->l_cred, l, 0, 0)) != 0)
477 		return (error);
478 
479 	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
480 
481 	bp  = NULL; /* both used in error_exit */
482 	pmp = NULL;
483 
484 	/*
485  	 * We need the disklabel to calculate the size of a FAT entry
486 	 * later on. Also make sure the partition contains a filesystem
487 	 * of type FS_MSDOS. This doesn't work for floppies, so we have
488 	 * to check for them too.
489  	 *
490  	 * There might still be parts of the msdos fs driver which assume
491 	 * that the size of a disk block will always be 512 bytes.
492 	 * Let's root them out...
493 	 */
494 	error = VOP_IOCTL(devvp, DIOCGPART, &dpart, FREAD, NOCRED);
495 	if (error == 0) {
496 		secsize = dpart.disklab->d_secsize;
497 		dtype = dpart.disklab->d_type;
498 		fstype = dpart.part->p_fstype;
499 		psize = dpart.part->p_size;
500 	} else {
501 		struct dkwedge_info dkw;
502 		error = VOP_IOCTL(devvp, DIOCGWEDGEINFO, &dkw, FREAD, NOCRED);
503 		secsize = 512;	/* XXX */
504 		dtype = DTYPE_FLOPPY; /* XXX */
505 		fstype = FS_MSDOS;
506 		psize = -1;
507 		if (error) {
508 			if (error != ENOTTY) {
509 				DPRINTF(("Error getting partition info %d\n",
510 				    error));
511 				goto error_exit;
512 			}
513 		} else {
514 			fstype = strcmp(dkw.dkw_ptype, DKW_PTYPE_FAT) == 0 ?
515 			    FS_MSDOS : -1;
516 			psize = dkw.dkw_size;
517 		}
518 	}
519 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
520 		bsize = secsize;
521 		if (bsize != 512) {
522 			DPRINTF(("bsize %d dtype %d fstype %d\n", bsize, dtype,
523 			    fstype));
524 			error = EINVAL;
525 			goto error_exit;
526 		}
527 	} else
528 		bsize = 0;
529 
530 	/*
531 	 * Read the boot sector of the filesystem, and then check the
532 	 * boot signature.  If not a dos boot sector then error out.
533 	 */
534 	if ((error = bread(devvp, 0, secsize, NOCRED, 0, &bp)) != 0)
535 		goto error_exit;
536 	bsp = (union bootsector *)bp->b_data;
537 	b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
538 	b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
539 	b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
540 
541 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
542 		if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
543 		    || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
544 			DPRINTF(("bootsig0 %d bootsig1 %d\n",
545 			    bsp->bs50.bsBootSectSig0,
546 			    bsp->bs50.bsBootSectSig1));
547 			error = EINVAL;
548 			goto error_exit;
549 		}
550 	}
551 
552 	pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK);
553 	memset(pmp, 0, sizeof *pmp);
554 	pmp->pm_mountp = mp;
555 
556 	/*
557 	 * Compute several useful quantities from the bpb in the
558 	 * bootsector.  Copy in the dos 5 variant of the bpb then fix up
559 	 * the fields that are different between dos 5 and dos 3.3.
560 	 */
561 	SecPerClust = b50->bpbSecPerClust;
562 	pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
563 	pmp->pm_ResSectors = getushort(b50->bpbResSectors);
564 	pmp->pm_FATs = b50->bpbFATs;
565 	pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
566 	pmp->pm_Sectors = getushort(b50->bpbSectors);
567 	pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
568 	pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
569 	pmp->pm_Heads = getushort(b50->bpbHeads);
570 	pmp->pm_Media = b50->bpbMedia;
571 
572 	if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
573 		/* XXX - We should probably check more values here */
574     		if (!pmp->pm_BytesPerSec || !SecPerClust
575 	    		|| pmp->pm_SecPerTrack > 63) {
576 			DPRINTF(("bytespersec %d secperclust %d "
577 			    "secpertrack %d\n",
578 			    pmp->pm_BytesPerSec, SecPerClust,
579 			    pmp->pm_SecPerTrack));
580 			error = EINVAL;
581 			goto error_exit;
582 		}
583 	}
584 
585 	if (pmp->pm_Sectors == 0) {
586 		pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
587 		pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
588 	} else {
589 		pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
590 		pmp->pm_HugeSectors = pmp->pm_Sectors;
591 	}
592 
593 	if (pmp->pm_RootDirEnts == 0) {
594 		unsigned short vers = getushort(b710->bpbFSVers);
595 		/*
596 		 * Some say that bsBootSectSig[23] must be zero, but
597 		 * Windows does not require this and some digital cameras
598 		 * do not set these to zero.  Therefore, do not insist.
599 		 */
600 		if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) {
601 			DPRINTF(("sectors %d fatsecs %lu vers %d\n",
602 			    pmp->pm_Sectors, pmp->pm_FATsecs, vers));
603 			error = EINVAL;
604 			goto error_exit;
605 		}
606 		pmp->pm_fatmask = FAT32_MASK;
607 		pmp->pm_fatmult = 4;
608 		pmp->pm_fatdiv = 1;
609 		pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
610 
611 		/* mirrorring is enabled if the FATMIRROR bit is not set */
612 		if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
613 			pmp->pm_flags |= MSDOSFS_FATMIRROR;
614 		else
615 			pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
616 	} else
617 		pmp->pm_flags |= MSDOSFS_FATMIRROR;
618 
619 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
620 		if (FAT32(pmp)) {
621 			DPRINTF(("fat32 for gemdos\n"));
622 			/*
623 			 * GEMDOS doesn't know fat32.
624 			 */
625 			error = EINVAL;
626 			goto error_exit;
627 		}
628 
629 		/*
630 		 * Check a few values (could do some more):
631 		 * - logical sector size: power of 2, >= block size
632 		 * - sectors per cluster: power of 2, >= 1
633 		 * - number of sectors:   >= 1, <= size of partition
634 		 */
635 		if ( (SecPerClust == 0)
636 		  || (SecPerClust & (SecPerClust - 1))
637 		  || (pmp->pm_BytesPerSec < bsize)
638 		  || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
639 		  || (pmp->pm_HugeSectors == 0)
640 		  || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize)
641 		      > psize)) {
642 			DPRINTF(("consistency checks for gemdos\n"));
643 			error = EINVAL;
644 			goto error_exit;
645 		}
646 		/*
647 		 * XXX - Many parts of the msdos fs driver seem to assume that
648 		 * the number of bytes per logical sector (BytesPerSec) will
649 		 * always be the same as the number of bytes per disk block
650 		 * Let's pretend it is.
651 		 */
652 		tmp = pmp->pm_BytesPerSec / bsize;
653 		pmp->pm_BytesPerSec  = bsize;
654 		pmp->pm_HugeSectors *= tmp;
655 		pmp->pm_HiddenSects *= tmp;
656 		pmp->pm_ResSectors  *= tmp;
657 		pmp->pm_Sectors     *= tmp;
658 		pmp->pm_FATsecs     *= tmp;
659 		SecPerClust         *= tmp;
660 	}
661 
662 	/* Check that fs has nonzero FAT size */
663 	if (pmp->pm_FATsecs == 0) {
664 		DPRINTF(("FATsecs is 0\n"));
665 		error = EINVAL;
666 		goto error_exit;
667 	}
668 
669 	pmp->pm_fatblk = pmp->pm_ResSectors;
670 	if (FAT32(pmp)) {
671 		pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
672 		pmp->pm_firstcluster = pmp->pm_fatblk
673 			+ (pmp->pm_FATs * pmp->pm_FATsecs);
674 		pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
675 	} else {
676 		pmp->pm_rootdirblk = pmp->pm_fatblk +
677 			(pmp->pm_FATs * pmp->pm_FATsecs);
678 		pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
679 				       + pmp->pm_BytesPerSec - 1)
680 			/ pmp->pm_BytesPerSec;/* in sectors */
681 		pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
682 	}
683 
684 	pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
685 	    SecPerClust;
686 	pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
687 	pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
688 
689 	if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
690 		if (pmp->pm_nmbrofclusters <= (0xff0 - 2)
691 		      && (dtype == DTYPE_FLOPPY
692 			  || (dtype == DTYPE_VND
693 				&& (pmp->pm_Heads == 1 || pmp->pm_Heads == 2)))
694 		    ) {
695 			pmp->pm_fatmask = FAT12_MASK;
696 			pmp->pm_fatmult = 3;
697 			pmp->pm_fatdiv = 2;
698 		} else {
699 			pmp->pm_fatmask = FAT16_MASK;
700 			pmp->pm_fatmult = 2;
701 			pmp->pm_fatdiv = 1;
702 		}
703 	} else if (pmp->pm_fatmask == 0) {
704 		if (pmp->pm_maxcluster
705 		    <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
706 			/*
707 			 * This will usually be a floppy disk. This size makes
708 			 * sure that one fat entry will not be split across
709 			 * multiple blocks.
710 			 */
711 			pmp->pm_fatmask = FAT12_MASK;
712 			pmp->pm_fatmult = 3;
713 			pmp->pm_fatdiv = 2;
714 		} else {
715 			pmp->pm_fatmask = FAT16_MASK;
716 			pmp->pm_fatmult = 2;
717 			pmp->pm_fatdiv = 1;
718 		}
719 	}
720 	if (FAT12(pmp))
721 		pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
722 	else
723 		pmp->pm_fatblocksize = MAXBSIZE;
724 
725 	pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
726 	pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
727 
728 	/*
729 	 * Compute mask and shift value for isolating cluster relative byte
730 	 * offsets and cluster numbers from a file offset.
731 	 */
732 	pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
733 	pmp->pm_crbomask = pmp->pm_bpcluster - 1;
734 	pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
735 
736 	/*
737 	 * Check for valid cluster size
738 	 * must be a power of 2
739 	 */
740 	if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
741 		DPRINTF(("bpcluster %lu cnshift %lu\n",
742 		    pmp->pm_bpcluster, pmp->pm_cnshift));
743 		error = EINVAL;
744 		goto error_exit;
745 	}
746 
747 	/*
748 	 * Release the bootsector buffer.
749 	 */
750 	brelse(bp, BC_AGE);
751 	bp = NULL;
752 
753 	/*
754 	 * Check FSInfo.
755 	 */
756 	if (pmp->pm_fsinfo) {
757 		struct fsinfo *fp;
758 
759 		/*
760 		 * XXX	If the fsinfo block is stored on media with
761 		 *	2KB or larger sectors, is the fsinfo structure
762 		 *	padded at the end or in the middle?
763 		 */
764 		if ((error = bread(devvp, de_bn2kb(pmp, pmp->pm_fsinfo),
765 		    pmp->pm_BytesPerSec, NOCRED, 0, &bp)) != 0)
766 			goto error_exit;
767 		fp = (struct fsinfo *)bp->b_data;
768 		if (!memcmp(fp->fsisig1, "RRaA", 4)
769 		    && !memcmp(fp->fsisig2, "rrAa", 4)
770 		    && !memcmp(fp->fsisig3, "\0\0\125\252", 4)
771 		    && !memcmp(fp->fsisig4, "\0\0\125\252", 4))
772 			pmp->pm_nxtfree = getulong(fp->fsinxtfree);
773 		else
774 			pmp->pm_fsinfo = 0;
775 		brelse(bp, 0);
776 		bp = NULL;
777 	}
778 
779 	/*
780 	 * Check and validate (or perhaps invalidate?) the fsinfo structure?
781 	 * XXX
782 	 */
783 	if (pmp->pm_fsinfo) {
784 		if (pmp->pm_nxtfree == (u_long)-1)
785 			pmp->pm_fsinfo = 0;
786 	}
787 
788 	/*
789 	 * Allocate memory for the bitmap of allocated clusters, and then
790 	 * fill it in.
791 	 */
792 	pmp->pm_inusemap = malloc(((pmp->pm_maxcluster + N_INUSEBITS - 1)
793 				   / N_INUSEBITS)
794 				  * sizeof(*pmp->pm_inusemap),
795 				  M_MSDOSFSFAT, M_WAITOK);
796 
797 	/*
798 	 * fillinusemap() needs pm_devvp.
799 	 */
800 	pmp->pm_dev = dev;
801 	pmp->pm_devvp = devvp;
802 
803 	/*
804 	 * Have the inuse map filled in.
805 	 */
806 	if ((error = fillinusemap(pmp)) != 0) {
807 		DPRINTF(("fillinusemap %d\n", error));
808 		goto error_exit;
809 	}
810 
811 	/*
812 	 * If they want fat updates to be synchronous then let them suffer
813 	 * the performance degradation in exchange for the on disk copy of
814 	 * the fat being correct just about all the time.  I suppose this
815 	 * would be a good thing to turn on if the kernel is still flakey.
816 	 */
817 	if (mp->mnt_flag & MNT_SYNCHRONOUS)
818 		pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
819 
820 	/*
821 	 * Finish up.
822 	 */
823 	if (ronly)
824 		pmp->pm_flags |= MSDOSFSMNT_RONLY;
825 	else
826 		pmp->pm_fmod = 1;
827 	mp->mnt_data = pmp;
828 	mp->mnt_stat.f_fsidx.__fsid_val[0] = (long)dev;
829 	mp->mnt_stat.f_fsidx.__fsid_val[1] = makefstype(MOUNT_MSDOS);
830 	mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
831 	mp->mnt_stat.f_namemax = MSDOSFS_NAMEMAX(pmp);
832 	mp->mnt_flag |= MNT_LOCAL;
833 	mp->mnt_dev_bshift = pmp->pm_bnshift;
834 	mp->mnt_fs_bshift = pmp->pm_cnshift;
835 
836 	/*
837 	 * If we ever do quotas for DOS filesystems this would be a place
838 	 * to fill in the info in the msdosfsmount structure. You dolt,
839 	 * quotas on dos filesystems make no sense because files have no
840 	 * owners on dos filesystems. of course there is some empty space
841 	 * in the directory entry where we could put uid's and gid's.
842 	 */
843 
844 	devvp->v_specmountpoint = mp;
845 
846 	return (0);
847 
848 error_exit:;
849 	if (bp)
850 		brelse(bp, BC_AGE);
851 	if (pmp) {
852 		if (pmp->pm_inusemap)
853 			free(pmp->pm_inusemap, M_MSDOSFSFAT);
854 		free(pmp, M_MSDOSFSMNT);
855 		mp->mnt_data = NULL;
856 	}
857 	return (error);
858 }
859 
860 int
861 msdosfs_start(struct mount *mp, int flags)
862 {
863 
864 	return (0);
865 }
866 
867 /*
868  * Unmount the filesystem described by mp.
869  */
870 int
871 msdosfs_unmount(struct mount *mp, int mntflags)
872 {
873 	struct msdosfsmount *pmp;
874 	int error, flags;
875 
876 	flags = 0;
877 	if (mntflags & MNT_FORCE)
878 		flags |= FORCECLOSE;
879 	if ((error = vflush(mp, NULLVP, flags)) != 0)
880 		return (error);
881 	pmp = VFSTOMSDOSFS(mp);
882 	if (pmp->pm_devvp->v_type != VBAD)
883 		pmp->pm_devvp->v_specmountpoint = NULL;
884 #ifdef MSDOSFS_DEBUG
885 	{
886 		struct vnode *vp = pmp->pm_devvp;
887 
888 		printf("msdosfs_umount(): just before calling VOP_CLOSE()\n");
889 		printf("flag %08x, usecount %d, writecount %d, holdcnt %d\n",
890 		    vp->v_vflag | vp->v_iflag | vp->v_uflag, vp->v_usecount,
891 		    vp->v_writecount, vp->v_holdcnt);
892 		printf("mount %p, op %p\n",
893 		    vp->v_mount, vp->v_op);
894 		printf("freef %p, freeb %p, mount %p\n",
895 		    vp->v_freelist.tqe_next, vp->v_freelist.tqe_prev,
896 		    vp->v_mount);
897 		printf("cleanblkhd %p, dirtyblkhd %p, numoutput %d, type %d\n",
898 		    vp->v_cleanblkhd.lh_first,
899 		    vp->v_dirtyblkhd.lh_first,
900 		    vp->v_numoutput, vp->v_type);
901 		printf("union %p, tag %d, data[0] %08x, data[1] %08x\n",
902 		    vp->v_socket, vp->v_tag,
903 		    ((u_int *)vp->v_data)[0],
904 		    ((u_int *)vp->v_data)[1]);
905 	}
906 #endif
907 	vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
908 	error = VOP_CLOSE(pmp->pm_devvp,
909 	    pmp->pm_flags & MSDOSFSMNT_RONLY ? FREAD : FREAD|FWRITE, NOCRED);
910 	vput(pmp->pm_devvp);
911 	free(pmp->pm_inusemap, M_MSDOSFSFAT);
912 	free(pmp, M_MSDOSFSMNT);
913 	mp->mnt_data = NULL;
914 	mp->mnt_flag &= ~MNT_LOCAL;
915 	return (error);
916 }
917 
918 int
919 msdosfs_root(struct mount *mp, struct vnode **vpp)
920 {
921 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
922 	struct denode *ndep;
923 	int error;
924 
925 #ifdef MSDOSFS_DEBUG
926 	printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
927 #endif
928 	if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0)
929 		return (error);
930 	*vpp = DETOV(ndep);
931 	return (0);
932 }
933 
934 int
935 msdosfs_statvfs(struct mount *mp, struct statvfs *sbp)
936 {
937 	struct msdosfsmount *pmp;
938 
939 	pmp = VFSTOMSDOSFS(mp);
940 	sbp->f_bsize = pmp->pm_bpcluster;
941 	sbp->f_frsize = sbp->f_bsize;
942 	sbp->f_iosize = pmp->pm_bpcluster;
943 	sbp->f_blocks = pmp->pm_nmbrofclusters;
944 	sbp->f_bfree = pmp->pm_freeclustercount;
945 	sbp->f_bavail = pmp->pm_freeclustercount;
946 	sbp->f_bresvd = 0;
947 	sbp->f_files = pmp->pm_RootDirEnts;			/* XXX */
948 	sbp->f_ffree = 0;	/* what to put in here? */
949 	sbp->f_favail = 0;	/* what to put in here? */
950 	sbp->f_fresvd = 0;
951 	copy_statvfs_info(sbp, mp);
952 	return (0);
953 }
954 
955 int
956 msdosfs_sync(struct mount *mp, int waitfor, kauth_cred_t cred)
957 {
958 	struct vnode *vp, *mvp;
959 	struct denode *dep;
960 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
961 	int error, allerror = 0;
962 
963 	/*
964 	 * If we ever switch to not updating all of the fats all the time,
965 	 * this would be the place to update them from the first one.
966 	 */
967 	if (pmp->pm_fmod != 0) {
968 		if (pmp->pm_flags & MSDOSFSMNT_RONLY)
969 			panic("msdosfs_sync: rofs mod");
970 		else {
971 			/* update fats here */
972 		}
973 	}
974 	/* Allocate a marker vnode. */
975 	if ((mvp = vnalloc(mp)) == NULL)
976 		return ENOMEM;
977 	/*
978 	 * Write back each (modified) denode.
979 	 */
980 	mutex_enter(&mntvnode_lock);
981 loop:
982 	for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp; vp = vunmark(mvp)) {
983 		vmark(mvp, vp);
984 		if (vp->v_mount != mp || vismarker(vp))
985 			continue;
986 		mutex_enter(&vp->v_interlock);
987 		dep = VTODE(vp);
988 		if (waitfor == MNT_LAZY || vp->v_type == VNON ||
989 		    (((dep->de_flag &
990 		    (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0) &&
991 		     (LIST_EMPTY(&vp->v_dirtyblkhd) &&
992 		      UVM_OBJ_IS_CLEAN(&vp->v_uobj)))) {
993 			mutex_exit(&vp->v_interlock);
994 			continue;
995 		}
996 		mutex_exit(&mntvnode_lock);
997 		error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK);
998 		if (error) {
999 			mutex_enter(&mntvnode_lock);
1000 			if (error == ENOENT) {
1001 				(void)vunmark(mvp);
1002 				goto loop;
1003 			}
1004 			continue;
1005 		}
1006 		if ((error = VOP_FSYNC(vp, cred,
1007 		    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0)) != 0)
1008 			allerror = error;
1009 		vput(vp);
1010 		mutex_enter(&mntvnode_lock);
1011 	}
1012 	mutex_exit(&mntvnode_lock);
1013 	vnfree(mvp);
1014 
1015 	/*
1016 	 * Force stale file system control information to be flushed.
1017 	 */
1018 	if ((error = VOP_FSYNC(pmp->pm_devvp, cred,
1019 	    waitfor == MNT_WAIT ? FSYNC_WAIT : 0, 0, 0)) != 0)
1020 		allerror = error;
1021 	return (allerror);
1022 }
1023 
1024 int
1025 msdosfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
1026 {
1027 	struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
1028 	struct defid defh;
1029 	struct denode *dep;
1030 	int error;
1031 
1032 	if (fhp->fid_len != sizeof(struct defid)) {
1033 		DPRINTF(("fid_len %d %zd\n", fhp->fid_len,
1034 		    sizeof(struct defid)));
1035 		return EINVAL;
1036 	}
1037 
1038 	memcpy(&defh, fhp, sizeof(defh));
1039 	error = deget(pmp, defh.defid_dirclust, defh.defid_dirofs, &dep);
1040 	if (error) {
1041 		DPRINTF(("deget %d\n", error));
1042 		*vpp = NULLVP;
1043 		return (error);
1044 	}
1045 	*vpp = DETOV(dep);
1046 	return (0);
1047 }
1048 
1049 int
1050 msdosfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size)
1051 {
1052 	struct denode *dep;
1053 	struct defid defh;
1054 
1055 	if (*fh_size < sizeof(struct defid)) {
1056 		*fh_size = sizeof(struct defid);
1057 		return E2BIG;
1058 	}
1059 	*fh_size = sizeof(struct defid);
1060 	dep = VTODE(vp);
1061 	memset(&defh, 0, sizeof(defh));
1062 	defh.defid_len = sizeof(struct defid);
1063 	defh.defid_dirclust = dep->de_dirclust;
1064 	defh.defid_dirofs = dep->de_diroffset;
1065 	/* defh.defid_gen = dep->de_gen; */
1066 	memcpy(fhp, &defh, sizeof(defh));
1067 	return (0);
1068 }
1069 
1070 int
1071 msdosfs_vget(struct mount *mp, ino_t ino,
1072     struct vnode **vpp)
1073 {
1074 
1075 	return (EOPNOTSUPP);
1076 }
1077