xref: /netbsd-src/sys/dev/dksubr.c (revision 2c6fc41c810f5088457889d00eba558e8bc74d9e)
1 /* $NetBSD: dksubr.c,v 1.50 2014/05/25 19:23:49 bouyer Exp $ */
2 
3 /*-
4  * Copyright (c) 1996, 1997, 1998, 1999, 2002, 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe and Roland C. Dowdeswell.
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  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.50 2014/05/25 19:23:49 bouyer Exp $");
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/stat.h>
38 #include <sys/proc.h>
39 #include <sys/ioctl.h>
40 #include <sys/device.h>
41 #include <sys/disk.h>
42 #include <sys/disklabel.h>
43 #include <sys/buf.h>
44 #include <sys/bufq.h>
45 #include <sys/vnode.h>
46 #include <sys/fcntl.h>
47 #include <sys/namei.h>
48 #include <sys/module.h>
49 
50 #include <dev/dkvar.h>
51 
52 int	dkdebug = 0;
53 
54 #ifdef DEBUG
55 #define DKDB_FOLLOW	0x1
56 #define DKDB_INIT	0x2
57 #define DKDB_VNODE	0x4
58 
59 #define IFDEBUG(x,y)		if (dkdebug & (x)) y
60 #define DPRINTF(x,y)		IFDEBUG(x, printf y)
61 #define DPRINTF_FOLLOW(y)	DPRINTF(DKDB_FOLLOW, y)
62 #else
63 #define IFDEBUG(x,y)
64 #define DPRINTF(x,y)
65 #define DPRINTF_FOLLOW(y)
66 #endif
67 
68 static int dk_subr_modcmd(modcmd_t, void *);
69 
70 #define DKLABELDEV(dev)	\
71 	(MAKEDISKDEV(major((dev)), DISKUNIT((dev)), RAW_PART))
72 
73 static void	dk_makedisklabel(struct dk_intf *, struct dk_softc *);
74 
75 void
76 dk_sc_init(struct dk_softc *dksc, const char *xname)
77 {
78 
79 	memset(dksc, 0x0, sizeof(*dksc));
80 	strncpy(dksc->sc_xname, xname, DK_XNAME_SIZE);
81 	dksc->sc_dkdev.dk_name = dksc->sc_xname;
82 }
83 
84 /* ARGSUSED */
85 int
86 dk_open(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
87     int flags, int fmt, struct lwp *l)
88 {
89 	struct	disklabel *lp = dksc->sc_dkdev.dk_label;
90 	int	part = DISKPART(dev);
91 	int	pmask = 1 << part;
92 	int	ret = 0;
93 	struct disk *dk = &dksc->sc_dkdev;
94 
95 	DPRINTF_FOLLOW(("dk_open(%s, %p, 0x%"PRIx64", 0x%x)\n",
96 	    di->di_dkname, dksc, dev, flags));
97 
98 	mutex_enter(&dk->dk_openlock);
99 	part = DISKPART(dev);
100 
101 	/*
102 	 * If there are wedges, and this is not RAW_PART, then we
103 	 * need to fail.
104 	 */
105 	if (dk->dk_nwedges != 0 && part != RAW_PART) {
106 		ret = EBUSY;
107 		goto done;
108 	}
109 
110 	pmask = 1 << part;
111 
112 	/*
113 	 * If we're init'ed and there are no other open partitions then
114 	 * update the in-core disklabel.
115 	 */
116 	if ((dksc->sc_flags & DKF_INITED)) {
117 		if (dk->dk_openmask == 0) {
118 			dk_getdisklabel(di, dksc, dev);
119 		}
120 		/* XXX re-discover wedges? */
121 	}
122 
123 	/* Fail if we can't find the partition. */
124 	if ((part != RAW_PART) &&
125 	    (((dksc->sc_flags & DKF_INITED) == 0) ||
126 	    ((part >= lp->d_npartitions) ||
127 	    (lp->d_partitions[part].p_fstype == FS_UNUSED)))) {
128 		ret = ENXIO;
129 		goto done;
130 	}
131 
132 	/* Mark our unit as open. */
133 	switch (fmt) {
134 	case S_IFCHR:
135 		dk->dk_copenmask |= pmask;
136 		break;
137 	case S_IFBLK:
138 		dk->dk_bopenmask |= pmask;
139 		break;
140 	}
141 
142 	dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
143 
144 done:
145 	mutex_exit(&dk->dk_openlock);
146 	return ret;
147 }
148 
149 /* ARGSUSED */
150 int
151 dk_close(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
152     int flags, int fmt, struct lwp *l)
153 {
154 	int	part = DISKPART(dev);
155 	int	pmask = 1 << part;
156 	struct disk *dk = &dksc->sc_dkdev;
157 
158 	DPRINTF_FOLLOW(("dk_close(%s, %p, 0x%"PRIx64", 0x%x)\n",
159 	    di->di_dkname, dksc, dev, flags));
160 
161 	mutex_enter(&dk->dk_openlock);
162 
163 	switch (fmt) {
164 	case S_IFCHR:
165 		dk->dk_copenmask &= ~pmask;
166 		break;
167 	case S_IFBLK:
168 		dk->dk_bopenmask &= ~pmask;
169 		break;
170 	}
171 	dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
172 
173 	mutex_exit(&dk->dk_openlock);
174 	return 0;
175 }
176 
177 void
178 dk_strategy(struct dk_intf *di, struct dk_softc *dksc, struct buf *bp)
179 {
180 	int	s;
181 	int	wlabel;
182 	daddr_t	blkno;
183 
184 	DPRINTF_FOLLOW(("dk_strategy(%s, %p, %p)\n",
185 	    di->di_dkname, dksc, bp));
186 
187 	if (!(dksc->sc_flags & DKF_INITED)) {
188 		DPRINTF_FOLLOW(("dk_strategy: not inited\n"));
189 		bp->b_error  = ENXIO;
190 		biodone(bp);
191 		return;
192 	}
193 
194 	/* XXX look for some more errors, c.f. ld.c */
195 
196 	bp->b_resid = bp->b_bcount;
197 
198 	/* If there is nothing to do, then we are done */
199 	if (bp->b_bcount == 0) {
200 		biodone(bp);
201 		return;
202 	}
203 
204 	wlabel = dksc->sc_flags & (DKF_WLABEL|DKF_LABELLING);
205 	if (DISKPART(bp->b_dev) != RAW_PART &&
206 	    bounds_check_with_label(&dksc->sc_dkdev, bp, wlabel) <= 0) {
207 		biodone(bp);
208 		return;
209 	}
210 
211 	blkno = bp->b_blkno;
212 	if (DISKPART(bp->b_dev) != RAW_PART) {
213 		struct partition *pp;
214 
215 		pp =
216 		    &dksc->sc_dkdev.dk_label->d_partitions[DISKPART(bp->b_dev)];
217 		blkno += pp->p_offset;
218 	}
219 	bp->b_rawblkno = blkno;
220 
221 	/*
222 	 * Start the unit by calling the start routine
223 	 * provided by the individual driver.
224 	 */
225 	s = splbio();
226 	bufq_put(dksc->sc_bufq, bp);
227 	di->di_diskstart(dksc);
228 	splx(s);
229 	return;
230 }
231 
232 int
233 dk_size(struct dk_intf *di, struct dk_softc *dksc, dev_t dev)
234 {
235 	struct	disklabel *lp;
236 	int	is_open;
237 	int	part;
238 	int	size;
239 
240 	if ((dksc->sc_flags & DKF_INITED) == 0)
241 		return -1;
242 
243 	part = DISKPART(dev);
244 	is_open = dksc->sc_dkdev.dk_openmask & (1 << part);
245 
246 	if (!is_open && di->di_open(dev, 0, S_IFBLK, curlwp))
247 		return -1;
248 
249 	lp = dksc->sc_dkdev.dk_label;
250 	if (lp->d_partitions[part].p_fstype != FS_SWAP)
251 		size = -1;
252 	else
253 		size = lp->d_partitions[part].p_size *
254 		    (lp->d_secsize / DEV_BSIZE);
255 
256 	if (!is_open && di->di_close(dev, 0, S_IFBLK, curlwp))
257 		return 1;
258 
259 	return size;
260 }
261 
262 int
263 dk_ioctl(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
264 	    u_long cmd, void *data, int flag, struct lwp *l)
265 {
266 	struct	disklabel *lp;
267 	struct	disk *dk;
268 #ifdef __HAVE_OLD_DISKLABEL
269 	struct	disklabel newlabel;
270 #endif
271 	int	error = 0;
272 
273 	DPRINTF_FOLLOW(("dk_ioctl(%s, %p, 0x%"PRIx64", 0x%lx)\n",
274 	    di->di_dkname, dksc, dev, cmd));
275 
276 	/* ensure that the pseudo disk is open for writes for these commands */
277 	switch (cmd) {
278 	case DIOCSDINFO:
279 	case DIOCWDINFO:
280 #ifdef __HAVE_OLD_DISKLABEL
281 	case ODIOCSDINFO:
282 	case ODIOCWDINFO:
283 #endif
284 	case DIOCWLABEL:
285 	case DIOCAWEDGE:
286 	case DIOCDWEDGE:
287 		if ((flag & FWRITE) == 0)
288 			return EBADF;
289 	}
290 
291 	/* ensure that the pseudo-disk is initialized for these */
292 	switch (cmd) {
293 #ifdef DIOCGSECTORSIZE
294 	case DIOCGSECTORSIZE:
295 	case DIOCGMEDIASIZE:
296 #endif
297 	case DIOCGDINFO:
298 	case DIOCSDINFO:
299 	case DIOCWDINFO:
300 	case DIOCGPART:
301 	case DIOCWLABEL:
302 	case DIOCGDEFLABEL:
303 	case DIOCAWEDGE:
304 	case DIOCDWEDGE:
305 	case DIOCLWEDGES:
306 	case DIOCCACHESYNC:
307 #ifdef __HAVE_OLD_DISKLABEL
308 	case ODIOCGDINFO:
309 	case ODIOCSDINFO:
310 	case ODIOCWDINFO:
311 	case ODIOCGDEFLABEL:
312 #endif
313 		if ((dksc->sc_flags & DKF_INITED) == 0)
314 			return ENXIO;
315 	}
316 
317 	switch (cmd) {
318 #ifdef DIOCGSECTORSIZE
319 	case DIOCGSECTORSIZE:
320 		*(u_int *)data = dksc->sc_dkdev.dk_geom.dg_secsize;
321 		return 0;
322 	case DIOCGMEDIASIZE:
323 		*(off_t *)data =
324 		    (off_t)dksc->sc_dkdev.dk_geom.dg_secsize *
325 		    dksc->sc_dkdev.dk_geom.dg_nsectors;
326 		return 0;
327 #endif
328 
329 	case DIOCGDINFO:
330 		*(struct disklabel *)data = *(dksc->sc_dkdev.dk_label);
331 		break;
332 
333 #ifdef __HAVE_OLD_DISKLABEL
334 	case ODIOCGDINFO:
335 		newlabel = *(dksc->sc_dkdev.dk_label);
336 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
337 			return ENOTTY;
338 		memcpy(data, &newlabel, sizeof (struct olddisklabel));
339 		break;
340 #endif
341 
342 	case DIOCGPART:
343 		((struct partinfo *)data)->disklab = dksc->sc_dkdev.dk_label;
344 		((struct partinfo *)data)->part =
345 		    &dksc->sc_dkdev.dk_label->d_partitions[DISKPART(dev)];
346 		break;
347 
348 	case DIOCWDINFO:
349 	case DIOCSDINFO:
350 #ifdef __HAVE_OLD_DISKLABEL
351 	case ODIOCWDINFO:
352 	case ODIOCSDINFO:
353 #endif
354 #ifdef __HAVE_OLD_DISKLABEL
355 		if (cmd == ODIOCSDINFO || cmd == ODIOCWDINFO) {
356 			memset(&newlabel, 0, sizeof newlabel);
357 			memcpy(&newlabel, data, sizeof (struct olddisklabel));
358 			lp = &newlabel;
359 		} else
360 #endif
361 		lp = (struct disklabel *)data;
362 
363 		dk = &dksc->sc_dkdev;
364 		mutex_enter(&dk->dk_openlock);
365 		dksc->sc_flags |= DKF_LABELLING;
366 
367 		error = setdisklabel(dksc->sc_dkdev.dk_label,
368 		    lp, 0, dksc->sc_dkdev.dk_cpulabel);
369 		if (error == 0) {
370 			if (cmd == DIOCWDINFO
371 #ifdef __HAVE_OLD_DISKLABEL
372 			    || cmd == ODIOCWDINFO
373 #endif
374 			   )
375 				error = writedisklabel(DKLABELDEV(dev),
376 				    di->di_strategy, dksc->sc_dkdev.dk_label,
377 				    dksc->sc_dkdev.dk_cpulabel);
378 		}
379 
380 		dksc->sc_flags &= ~DKF_LABELLING;
381 		mutex_exit(&dk->dk_openlock);
382 		break;
383 
384 	case DIOCWLABEL:
385 		if (*(int *)data != 0)
386 			dksc->sc_flags |= DKF_WLABEL;
387 		else
388 			dksc->sc_flags &= ~DKF_WLABEL;
389 		break;
390 
391 	case DIOCGDEFLABEL:
392 		dk_getdefaultlabel(di, dksc, (struct disklabel *)data);
393 		break;
394 
395 #ifdef __HAVE_OLD_DISKLABEL
396 	case ODIOCGDEFLABEL:
397 		dk_getdefaultlabel(di, dksc, &newlabel);
398 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
399 			return ENOTTY;
400 		memcpy(data, &newlabel, sizeof (struct olddisklabel));
401 		break;
402 #endif
403 
404 	case DIOCAWEDGE:
405 	    {
406 	    	struct dkwedge_info *dkw = (void *)data;
407 
408 		if ((flag & FWRITE) == 0)
409 			return (EBADF);
410 
411 		/* If the ioctl happens here, the parent is us. */
412 		strcpy(dkw->dkw_parent, dksc->sc_dkdev.dk_name);
413 		return (dkwedge_add(dkw));
414 	    }
415 
416 	case DIOCDWEDGE:
417 	    {
418 	    	struct dkwedge_info *dkw = (void *)data;
419 
420 		if ((flag & FWRITE) == 0)
421 			return (EBADF);
422 
423 		/* If the ioctl happens here, the parent is us. */
424 		strcpy(dkw->dkw_parent, dksc->sc_dkdev.dk_name);
425 		return (dkwedge_del(dkw));
426 	    }
427 
428 	case DIOCLWEDGES:
429 	    {
430 	    	struct dkwedge_list *dkwl = (void *)data;
431 
432 		return (dkwedge_list(&dksc->sc_dkdev, dkwl, l));
433 	    }
434 
435 	case DIOCGSTRATEGY:
436 	    {
437 		struct disk_strategy *dks = (void *)data;
438 		int s;
439 
440 		s = splbio();
441 		strlcpy(dks->dks_name, bufq_getstrategyname(dksc->sc_bufq),
442 		    sizeof(dks->dks_name));
443 		splx(s);
444 		dks->dks_paramlen = 0;
445 
446 		return 0;
447 	    }
448 
449 	case DIOCSSTRATEGY:
450 	    {
451 		struct disk_strategy *dks = (void *)data;
452 		struct bufq_state *new;
453 		struct bufq_state *old;
454 		int s;
455 
456 		if ((flag & FWRITE) == 0) {
457 			return EBADF;
458 		}
459 		if (dks->dks_param != NULL) {
460 			return EINVAL;
461 		}
462 		dks->dks_name[sizeof(dks->dks_name) - 1] = 0; /* ensure term */
463 		error = bufq_alloc(&new, dks->dks_name,
464 		    BUFQ_EXACT|BUFQ_SORT_RAWBLOCK);
465 		if (error) {
466 			return error;
467 		}
468 		s = splbio();
469 		old = dksc->sc_bufq;
470 		bufq_move(new, old);
471 		dksc->sc_bufq = new;
472 		splx(s);
473 		bufq_free(old);
474 
475 		return 0;
476 	    }
477 
478 	default:
479 		error = ENOTTY;
480 	}
481 
482 	return error;
483 }
484 
485 /*
486  * dk_dump dumps all of physical memory into the partition specified.
487  * This requires substantially more framework than {s,w}ddump, and hence
488  * is probably much more fragile.
489  *
490  * XXX: we currently do not implement this.
491  */
492 
493 #define DKF_READYFORDUMP	(DKF_INITED|DKF_TAKEDUMP)
494 #define DKFF_READYFORDUMP(x)	(((x) & DKF_READYFORDUMP) == DKF_READYFORDUMP)
495 static volatile int	dk_dumping = 0;
496 
497 /* ARGSUSED */
498 int
499 dk_dump(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
500     daddr_t blkno, void *va, size_t size)
501 {
502 
503 	/*
504 	 * ensure that we consider this device to be safe for dumping,
505 	 * and that the device is configured.
506 	 */
507 	if (!DKFF_READYFORDUMP(dksc->sc_flags))
508 		return ENXIO;
509 
510 	/* ensure that we are not already dumping */
511 	if (dk_dumping)
512 		return EFAULT;
513 	dk_dumping = 1;
514 
515 	/* XXX: unimplemented */
516 
517 	dk_dumping = 0;
518 
519 	/* XXX: actually for now, we are going to leave this alone */
520 	return ENXIO;
521 }
522 
523 /* ARGSUSED */
524 void
525 dk_getdefaultlabel(struct dk_intf *di, struct dk_softc *dksc,
526 		      struct disklabel *lp)
527 {
528 	struct disk_geom *dg = &dksc->sc_dkdev.dk_geom;
529 
530 	memset(lp, 0, sizeof(*lp));
531 
532 	lp->d_secperunit = dg->dg_secperunit;
533 	lp->d_secsize = dg->dg_secsize;
534 	lp->d_nsectors = dg->dg_nsectors;
535 	lp->d_ntracks = dg->dg_ntracks;
536 	lp->d_ncylinders = dg->dg_ncylinders;
537 	lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;
538 
539 	strncpy(lp->d_typename, di->di_dkname, sizeof(lp->d_typename));
540 	lp->d_type = di->di_dtype;
541 	strncpy(lp->d_packname, "fictitious", sizeof(lp->d_packname));
542 	lp->d_rpm = 3600;
543 	lp->d_interleave = 1;
544 	lp->d_flags = 0;
545 
546 	lp->d_partitions[RAW_PART].p_offset = 0;
547 	lp->d_partitions[RAW_PART].p_size = dg->dg_secperunit;
548 	lp->d_partitions[RAW_PART].p_fstype = FS_UNUSED;
549 	lp->d_npartitions = RAW_PART + 1;
550 
551 	lp->d_magic = DISKMAGIC;
552 	lp->d_magic2 = DISKMAGIC;
553 	lp->d_checksum = dkcksum(dksc->sc_dkdev.dk_label);
554 }
555 
556 /* ARGSUSED */
557 void
558 dk_getdisklabel(struct dk_intf *di, struct dk_softc *dksc, dev_t dev)
559 {
560 	struct	 disklabel *lp = dksc->sc_dkdev.dk_label;
561 	struct	 cpu_disklabel *clp = dksc->sc_dkdev.dk_cpulabel;
562 	struct disk_geom *dg = &dksc->sc_dkdev.dk_geom;
563 	struct	 partition *pp;
564 	int	 i;
565 	const char	*errstring;
566 
567 	memset(clp, 0x0, sizeof(*clp));
568 	dk_getdefaultlabel(di, dksc, lp);
569 	errstring = readdisklabel(DKLABELDEV(dev), di->di_strategy,
570 	    dksc->sc_dkdev.dk_label, dksc->sc_dkdev.dk_cpulabel);
571 	if (errstring) {
572 		dk_makedisklabel(di, dksc);
573 		if (dksc->sc_flags & DKF_WARNLABEL)
574 			printf("%s: %s\n", dksc->sc_xname, errstring);
575 		return;
576 	}
577 
578 	if ((dksc->sc_flags & DKF_LABELSANITY) == 0)
579 		return;
580 
581 	/* Sanity check */
582 	if (lp->d_secperunit != dg->dg_secperunit)
583 		printf("WARNING: %s: total sector size in disklabel (%d) "
584 		    "!= the size of %s (%" PRId64 ")\n", dksc->sc_xname,
585 		    lp->d_secperunit, di->di_dkname, dg->dg_secperunit);
586 
587 	for (i=0; i < lp->d_npartitions; i++) {
588 		pp = &lp->d_partitions[i];
589 		if (pp->p_offset + pp->p_size > dg->dg_secperunit)
590 			printf("WARNING: %s: end of partition `%c' exceeds "
591 			    "the size of %s (%" PRId64 ")\n", dksc->sc_xname,
592 			    'a' + i, di->di_dkname, dg->dg_secperunit);
593 	}
594 }
595 
596 /* ARGSUSED */
597 static void
598 dk_makedisklabel(struct dk_intf *di, struct dk_softc *dksc)
599 {
600 	struct	disklabel *lp = dksc->sc_dkdev.dk_label;
601 
602 	lp->d_partitions[RAW_PART].p_fstype = FS_BSDFFS;
603 	strncpy(lp->d_packname, "default label", sizeof(lp->d_packname));
604 	lp->d_checksum = dkcksum(lp);
605 }
606 
607 /* This function is taken from ccd.c:1.76  --rcd */
608 
609 /*
610  * XXX this function looks too generic for dksubr.c, shouldn't we
611  *     put it somewhere better?
612  */
613 
614 /*
615  * Lookup the provided name in the filesystem.  If the file exists,
616  * is a valid block device, and isn't being used by anyone else,
617  * set *vpp to the file's vnode.
618  */
619 int
620 dk_lookup(struct pathbuf *pb, struct lwp *l, struct vnode **vpp)
621 {
622 	struct nameidata nd;
623 	struct vnode *vp;
624 	struct vattr va;
625 	int     error;
626 
627 	if (l == NULL)
628 		return ESRCH;	/* Is ESRCH the best choice? */
629 
630 	NDINIT(&nd, LOOKUP, FOLLOW, pb);
631 	if ((error = vn_open(&nd, FREAD | FWRITE, 0)) != 0) {
632 		DPRINTF((DKDB_FOLLOW|DKDB_INIT),
633 		    ("dk_lookup: vn_open error = %d\n", error));
634 		return error;
635 	}
636 
637 	vp = nd.ni_vp;
638 	if ((error = VOP_GETATTR(vp, &va, l->l_cred)) != 0) {
639 		DPRINTF((DKDB_FOLLOW|DKDB_INIT),
640 		    ("dk_lookup: getattr error = %d\n", error));
641 		goto out;
642 	}
643 
644 	/* XXX: eventually we should handle VREG, too. */
645 	if (va.va_type != VBLK) {
646 		error = ENOTBLK;
647 		goto out;
648 	}
649 
650 	IFDEBUG(DKDB_VNODE, vprint("dk_lookup: vnode info", vp));
651 
652 	VOP_UNLOCK(vp);
653 	*vpp = vp;
654 	return 0;
655 out:
656 	VOP_UNLOCK(vp);
657 	(void) vn_close(vp, FREAD | FWRITE, l->l_cred);
658 	return error;
659 }
660 
661 MODULE(MODULE_CLASS_MISC, dk_subr, NULL);
662 
663 static int
664 dk_subr_modcmd(modcmd_t cmd, void *arg)
665 {
666 	switch (cmd) {
667 	case MODULE_CMD_INIT:
668 	case MODULE_CMD_FINI:
669 		return 0;
670 	case MODULE_CMD_STAT:
671 	case MODULE_CMD_AUTOUNLOAD:
672 	default:
673 		return ENOTTY;
674 	}
675 }
676