xref: /freebsd/sys/geom/geom_disk.c (revision a02aba5f3c73d7ed377f88327fedd11f70f23353)
1 /*-
2  * Copyright (c) 2002 Poul-Henning Kamp
3  * Copyright (c) 2002 Networks Associates Technology, Inc.
4  * All rights reserved.
5  *
6  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
7  * and NAI Labs, the Security Research Division of Network Associates, Inc.
8  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
9  * DARPA CHATS research program.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. The names of the authors may not be used to endorse or promote
20  *    products derived from this software without specific prior written
21  *    permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 #include "opt_geom.h"
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/kernel.h>
44 #include <sys/sysctl.h>
45 #include <sys/bio.h>
46 #include <sys/ctype.h>
47 #include <sys/fcntl.h>
48 #include <sys/malloc.h>
49 #include <sys/sbuf.h>
50 #include <sys/sysctl.h>
51 #include <sys/devicestat.h>
52 #include <machine/md_var.h>
53 
54 #include <sys/lock.h>
55 #include <sys/mutex.h>
56 #include <geom/geom.h>
57 #include <geom/geom_disk.h>
58 #include <geom/geom_int.h>
59 
60 #include <dev/led/led.h>
61 
62 struct g_disk_softc {
63 	struct disk		*dp;
64 	struct sysctl_ctx_list	sysctl_ctx;
65 	struct sysctl_oid	*sysctl_tree;
66 	char			led[64];
67 	uint32_t		state;
68 };
69 
70 static struct mtx g_disk_done_mtx;
71 
72 static g_access_t g_disk_access;
73 static g_init_t g_disk_init;
74 static g_fini_t g_disk_fini;
75 static g_start_t g_disk_start;
76 static g_ioctl_t g_disk_ioctl;
77 static g_dumpconf_t g_disk_dumpconf;
78 
79 static struct g_class g_disk_class = {
80 	.name = "DISK",
81 	.version = G_VERSION,
82 	.init = g_disk_init,
83 	.fini = g_disk_fini,
84 	.start = g_disk_start,
85 	.access = g_disk_access,
86 	.ioctl = g_disk_ioctl,
87 	.dumpconf = g_disk_dumpconf,
88 };
89 
90 SYSCTL_DECL(_kern_geom);
91 SYSCTL_NODE(_kern_geom, OID_AUTO, disk, CTLFLAG_RW, 0, "GEOM_DISK stuff");
92 
93 static void
94 g_disk_init(struct g_class *mp __unused)
95 {
96 
97 	mtx_init(&g_disk_done_mtx, "g_disk_done", NULL, MTX_DEF);
98 }
99 
100 static void
101 g_disk_fini(struct g_class *mp __unused)
102 {
103 
104 	mtx_destroy(&g_disk_done_mtx);
105 }
106 
107 DECLARE_GEOM_CLASS(g_disk_class, g_disk);
108 
109 static void __inline
110 g_disk_lock_giant(struct disk *dp)
111 {
112 	if (dp->d_flags & DISKFLAG_NEEDSGIANT)
113 		mtx_lock(&Giant);
114 }
115 
116 static void __inline
117 g_disk_unlock_giant(struct disk *dp)
118 {
119 	if (dp->d_flags & DISKFLAG_NEEDSGIANT)
120 		mtx_unlock(&Giant);
121 }
122 
123 static int
124 g_disk_access(struct g_provider *pp, int r, int w, int e)
125 {
126 	struct disk *dp;
127 	struct g_disk_softc *sc;
128 	int error;
129 
130 	g_trace(G_T_ACCESS, "g_disk_access(%s, %d, %d, %d)",
131 	    pp->name, r, w, e);
132 	g_topology_assert();
133 	sc = pp->geom->softc;
134 	if (sc == NULL || (dp = sc->dp) == NULL || dp->d_destroyed) {
135 		/*
136 		 * Allow decreasing access count even if disk is not
137 		 * avaliable anymore.
138 		 */
139 		if (r <= 0 && w <= 0 && e <= 0)
140 			return (0);
141 		return (ENXIO);
142 	}
143 	r += pp->acr;
144 	w += pp->acw;
145 	e += pp->ace;
146 	error = 0;
147 	if ((pp->acr + pp->acw + pp->ace) == 0 && (r + w + e) > 0) {
148 		if (dp->d_open != NULL) {
149 			g_disk_lock_giant(dp);
150 			error = dp->d_open(dp);
151 			if (bootverbose && error != 0)
152 				printf("Opened disk %s -> %d\n",
153 				    pp->name, error);
154 			g_disk_unlock_giant(dp);
155 		}
156 		pp->mediasize = dp->d_mediasize;
157 		pp->sectorsize = dp->d_sectorsize;
158 		if (dp->d_flags & DISKFLAG_CANDELETE)
159 			pp->flags |= G_PF_CANDELETE;
160 		else
161 			pp->flags &= ~G_PF_CANDELETE;
162 		pp->stripeoffset = dp->d_stripeoffset;
163 		pp->stripesize = dp->d_stripesize;
164 		dp->d_flags |= DISKFLAG_OPEN;
165 		if (dp->d_maxsize == 0) {
166 			printf("WARNING: Disk drive %s%d has no d_maxsize\n",
167 			    dp->d_name, dp->d_unit);
168 			dp->d_maxsize = DFLTPHYS;
169 		}
170 	} else if ((pp->acr + pp->acw + pp->ace) > 0 && (r + w + e) == 0) {
171 		if (dp->d_close != NULL) {
172 			g_disk_lock_giant(dp);
173 			error = dp->d_close(dp);
174 			if (error != 0)
175 				printf("Closed disk %s -> %d\n",
176 				    pp->name, error);
177 			g_disk_unlock_giant(dp);
178 		}
179 		sc->state = G_STATE_ACTIVE;
180 		if (sc->led[0] != 0)
181 			led_set(sc->led, "0");
182 		dp->d_flags &= ~DISKFLAG_OPEN;
183 	}
184 	return (error);
185 }
186 
187 static void
188 g_disk_kerneldump(struct bio *bp, struct disk *dp)
189 {
190 	struct g_kerneldump *gkd;
191 	struct g_geom *gp;
192 
193 	gkd = (struct g_kerneldump*)bp->bio_data;
194 	gp = bp->bio_to->geom;
195 	g_trace(G_T_TOPOLOGY, "g_disk_kernedump(%s, %jd, %jd)",
196 		gp->name, (intmax_t)gkd->offset, (intmax_t)gkd->length);
197 	if (dp->d_dump == NULL) {
198 		g_io_deliver(bp, ENODEV);
199 		return;
200 	}
201 	gkd->di.dumper = dp->d_dump;
202 	gkd->di.priv = dp;
203 	gkd->di.blocksize = dp->d_sectorsize;
204 	gkd->di.maxiosize = dp->d_maxsize;
205 	gkd->di.mediaoffset = gkd->offset;
206 	if ((gkd->offset + gkd->length) > dp->d_mediasize)
207 		gkd->length = dp->d_mediasize - gkd->offset;
208 	gkd->di.mediasize = gkd->length;
209 	g_io_deliver(bp, 0);
210 }
211 
212 static void
213 g_disk_setstate(struct bio *bp, struct g_disk_softc *sc)
214 {
215 	const char *cmd;
216 
217 	memcpy(&sc->state, bp->bio_data, sizeof(sc->state));
218 	if (sc->led[0] != 0) {
219 		switch (sc->state) {
220 		case G_STATE_FAILED:
221 			cmd = "1";
222 			break;
223 		case G_STATE_REBUILD:
224 			cmd = "f5";
225 			break;
226 		case G_STATE_RESYNC:
227 			cmd = "f1";
228 			break;
229 		default:
230 			cmd = "0";
231 			break;
232 		}
233 		led_set(sc->led, cmd);
234 	}
235 	g_io_deliver(bp, 0);
236 }
237 
238 static void
239 g_disk_done(struct bio *bp)
240 {
241 	struct bio *bp2;
242 	struct disk *dp;
243 	struct g_disk_softc *sc;
244 
245 	/* See "notes" for why we need a mutex here */
246 	/* XXX: will witness accept a mix of Giant/unGiant drivers here ? */
247 	mtx_lock(&g_disk_done_mtx);
248 	bp->bio_completed = bp->bio_length - bp->bio_resid;
249 
250 	bp2 = bp->bio_parent;
251 	if (bp2->bio_error == 0)
252 		bp2->bio_error = bp->bio_error;
253 	bp2->bio_completed += bp->bio_completed;
254 	if ((bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_DELETE)) &&
255 	    (sc = bp2->bio_to->geom->softc) &&
256 	    (dp = sc->dp)) {
257 		devstat_end_transaction_bio(dp->d_devstat, bp);
258 	}
259 	g_destroy_bio(bp);
260 	bp2->bio_inbed++;
261 	if (bp2->bio_children == bp2->bio_inbed) {
262 		bp2->bio_resid = bp2->bio_bcount - bp2->bio_completed;
263 		g_io_deliver(bp2, bp2->bio_error);
264 	}
265 	mtx_unlock(&g_disk_done_mtx);
266 }
267 
268 static int
269 g_disk_ioctl(struct g_provider *pp, u_long cmd, void * data, int fflag, struct thread *td)
270 {
271 	struct g_geom *gp;
272 	struct disk *dp;
273 	struct g_disk_softc *sc;
274 	int error;
275 
276 	gp = pp->geom;
277 	sc = gp->softc;
278 	dp = sc->dp;
279 
280 	if (dp->d_ioctl == NULL)
281 		return (ENOIOCTL);
282 	g_disk_lock_giant(dp);
283 	error = dp->d_ioctl(dp, cmd, data, fflag, td);
284 	g_disk_unlock_giant(dp);
285 	return(error);
286 }
287 
288 static void
289 g_disk_start(struct bio *bp)
290 {
291 	struct bio *bp2, *bp3;
292 	struct disk *dp;
293 	struct g_disk_softc *sc;
294 	int error;
295 	off_t off;
296 
297 	sc = bp->bio_to->geom->softc;
298 	if (sc == NULL || (dp = sc->dp) == NULL || dp->d_destroyed) {
299 		g_io_deliver(bp, ENXIO);
300 		return;
301 	}
302 	error = EJUSTRETURN;
303 	switch(bp->bio_cmd) {
304 	case BIO_DELETE:
305 		if (!(dp->d_flags & DISKFLAG_CANDELETE)) {
306 			error = 0;
307 			break;
308 		}
309 		/* fall-through */
310 	case BIO_READ:
311 	case BIO_WRITE:
312 		off = 0;
313 		bp3 = NULL;
314 		bp2 = g_clone_bio(bp);
315 		if (bp2 == NULL) {
316 			error = ENOMEM;
317 			break;
318 		}
319 		do {
320 			bp2->bio_offset += off;
321 			bp2->bio_length -= off;
322 			bp2->bio_data += off;
323 			if (bp2->bio_length > dp->d_maxsize) {
324 				/*
325 				 * XXX: If we have a stripesize we should really
326 				 * use it here.
327 				 */
328 				bp2->bio_length = dp->d_maxsize;
329 				off += dp->d_maxsize;
330 				/*
331 				 * To avoid a race, we need to grab the next bio
332 				 * before we schedule this one.  See "notes".
333 				 */
334 				bp3 = g_clone_bio(bp);
335 				if (bp3 == NULL)
336 					bp->bio_error = ENOMEM;
337 			}
338 			bp2->bio_done = g_disk_done;
339 			bp2->bio_pblkno = bp2->bio_offset / dp->d_sectorsize;
340 			bp2->bio_bcount = bp2->bio_length;
341 			bp2->bio_disk = dp;
342 			devstat_start_transaction_bio(dp->d_devstat, bp2);
343 			g_disk_lock_giant(dp);
344 			dp->d_strategy(bp2);
345 			g_disk_unlock_giant(dp);
346 			bp2 = bp3;
347 			bp3 = NULL;
348 		} while (bp2 != NULL);
349 		break;
350 	case BIO_GETATTR:
351 		/* Give the driver a chance to override */
352 		if (dp->d_getattr != NULL) {
353 			if (bp->bio_disk == NULL)
354 				bp->bio_disk = dp;
355 			error = dp->d_getattr(bp);
356 			if (error != -1)
357 				break;
358 			error = EJUSTRETURN;
359 		}
360 		if (g_handleattr_int(bp, "GEOM::candelete",
361 		    (dp->d_flags & DISKFLAG_CANDELETE) != 0))
362 			break;
363 		else if (g_handleattr_int(bp, "GEOM::fwsectors",
364 		    dp->d_fwsectors))
365 			break;
366 		else if (g_handleattr_int(bp, "GEOM::fwheads", dp->d_fwheads))
367 			break;
368 		else if (g_handleattr_off_t(bp, "GEOM::frontstuff", 0))
369 			break;
370 		else if (g_handleattr_str(bp, "GEOM::ident", dp->d_ident))
371 			break;
372 		else if (g_handleattr(bp, "GEOM::hba_vendor",
373 		    &dp->d_hba_vendor, 2))
374 			break;
375 		else if (g_handleattr(bp, "GEOM::hba_device",
376 		    &dp->d_hba_device, 2))
377 			break;
378 		else if (g_handleattr(bp, "GEOM::hba_subvendor",
379 		    &dp->d_hba_subvendor, 2))
380 			break;
381 		else if (g_handleattr(bp, "GEOM::hba_subdevice",
382 		    &dp->d_hba_subdevice, 2))
383 			break;
384 		else if (!strcmp(bp->bio_attribute, "GEOM::kerneldump"))
385 			g_disk_kerneldump(bp, dp);
386 		else if (!strcmp(bp->bio_attribute, "GEOM::setstate"))
387 			g_disk_setstate(bp, sc);
388 		else
389 			error = ENOIOCTL;
390 		break;
391 	case BIO_FLUSH:
392 		g_trace(G_T_TOPOLOGY, "g_disk_flushcache(%s)",
393 		    bp->bio_to->name);
394 		if (!(dp->d_flags & DISKFLAG_CANFLUSHCACHE)) {
395 			g_io_deliver(bp, ENODEV);
396 			return;
397 		}
398 		bp2 = g_clone_bio(bp);
399 		if (bp2 == NULL) {
400 			g_io_deliver(bp, ENOMEM);
401 			return;
402 		}
403 		bp2->bio_done = g_disk_done;
404 		bp2->bio_disk = dp;
405 		g_disk_lock_giant(dp);
406 		dp->d_strategy(bp2);
407 		g_disk_unlock_giant(dp);
408 		break;
409 	default:
410 		error = EOPNOTSUPP;
411 		break;
412 	}
413 	if (error != EJUSTRETURN)
414 		g_io_deliver(bp, error);
415 	return;
416 }
417 
418 static void
419 g_disk_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp)
420 {
421 	struct disk *dp;
422 	struct g_disk_softc *sc;
423 
424 	sc = gp->softc;
425 	if (sc == NULL || (dp = sc->dp) == NULL)
426 		return;
427 	if (indent == NULL) {
428 		sbuf_printf(sb, " hd %u", dp->d_fwheads);
429 		sbuf_printf(sb, " sc %u", dp->d_fwsectors);
430 		return;
431 	}
432 	if (pp != NULL) {
433 		sbuf_printf(sb, "%s<fwheads>%u</fwheads>\n",
434 		    indent, dp->d_fwheads);
435 		sbuf_printf(sb, "%s<fwsectors>%u</fwsectors>\n",
436 		    indent, dp->d_fwsectors);
437 		sbuf_printf(sb, "%s<ident>%s</ident>\n", indent, dp->d_ident);
438 		sbuf_printf(sb, "%s<descr>%s</descr>\n", indent, dp->d_descr);
439 	}
440 }
441 
442 static void
443 g_disk_create(void *arg, int flag)
444 {
445 	struct g_geom *gp;
446 	struct g_provider *pp;
447 	struct disk *dp;
448 	struct g_disk_softc *sc;
449 	char tmpstr[80];
450 
451 	if (flag == EV_CANCEL)
452 		return;
453 	g_topology_assert();
454 	dp = arg;
455 	sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
456 	sc->dp = dp;
457 	gp = g_new_geomf(&g_disk_class, "%s%d", dp->d_name, dp->d_unit);
458 	gp->softc = sc;
459 	pp = g_new_providerf(gp, "%s", gp->name);
460 	pp->mediasize = dp->d_mediasize;
461 	pp->sectorsize = dp->d_sectorsize;
462 	if (dp->d_flags & DISKFLAG_CANDELETE)
463 		pp->flags |= G_PF_CANDELETE;
464 	pp->stripeoffset = dp->d_stripeoffset;
465 	pp->stripesize = dp->d_stripesize;
466 	if (bootverbose)
467 		printf("GEOM: new disk %s\n", gp->name);
468 	sysctl_ctx_init(&sc->sysctl_ctx);
469 	snprintf(tmpstr, sizeof(tmpstr), "GEOM disk %s", gp->name);
470 	sc->sysctl_tree = SYSCTL_ADD_NODE(&sc->sysctl_ctx,
471 		SYSCTL_STATIC_CHILDREN(_kern_geom_disk), OID_AUTO, gp->name,
472 		CTLFLAG_RD, 0, tmpstr);
473 	if (sc->sysctl_tree != NULL) {
474 		snprintf(tmpstr, sizeof(tmpstr),
475 		    "kern.geom.disk.%s.led", gp->name);
476 		TUNABLE_STR_FETCH(tmpstr, sc->led, sizeof(sc->led));
477 		SYSCTL_ADD_STRING(&sc->sysctl_ctx,
478 		    SYSCTL_CHILDREN(sc->sysctl_tree), OID_AUTO, "led",
479 		    CTLFLAG_RW | CTLFLAG_TUN, sc->led, sizeof(sc->led),
480 		    "LED name");
481 	}
482 	pp->private = sc;
483 	dp->d_geom = gp;
484 	g_error_provider(pp, 0);
485 }
486 
487 static void
488 g_disk_destroy(void *ptr, int flag)
489 {
490 	struct disk *dp;
491 	struct g_geom *gp;
492 	struct g_disk_softc *sc;
493 
494 	g_topology_assert();
495 	dp = ptr;
496 	gp = dp->d_geom;
497 	if (gp != NULL) {
498 		sc = gp->softc;
499 		if (sc->sysctl_tree != NULL) {
500 			sysctl_ctx_free(&sc->sysctl_ctx);
501 			sc->sysctl_tree = NULL;
502 		}
503 		if (sc->led[0] != 0) {
504 			led_set(sc->led, "0");
505 			sc->led[0] = 0;
506 		}
507 		g_free(sc);
508 		gp->softc = NULL;
509 		g_wither_geom(gp, ENXIO);
510 	}
511 	g_free(dp);
512 }
513 
514 /*
515  * We only allow printable characters in disk ident,
516  * the rest is converted to 'x<HH>'.
517  */
518 static void
519 g_disk_ident_adjust(char *ident, size_t size)
520 {
521 	char *p, tmp[4], newid[DISK_IDENT_SIZE];
522 
523 	newid[0] = '\0';
524 	for (p = ident; *p != '\0'; p++) {
525 		if (isprint(*p)) {
526 			tmp[0] = *p;
527 			tmp[1] = '\0';
528 		} else {
529 			snprintf(tmp, sizeof(tmp), "x%02hhx",
530 			    *(unsigned char *)p);
531 		}
532 		if (strlcat(newid, tmp, sizeof(newid)) >= sizeof(newid))
533 			break;
534 	}
535 	bzero(ident, size);
536 	strlcpy(ident, newid, size);
537 }
538 
539 struct disk *
540 disk_alloc()
541 {
542 	struct disk *dp;
543 
544 	dp = g_malloc(sizeof *dp, M_WAITOK | M_ZERO);
545 	return (dp);
546 }
547 
548 void
549 disk_create(struct disk *dp, int version)
550 {
551 	if (version != DISK_VERSION_00 && version != DISK_VERSION_01) {
552 		printf("WARNING: Attempt to add disk %s%d %s",
553 		    dp->d_name, dp->d_unit,
554 		    " using incompatible ABI version of disk(9)\n");
555 		printf("WARNING: Ignoring disk %s%d\n",
556 		    dp->d_name, dp->d_unit);
557 		return;
558 	}
559 	KASSERT(dp->d_strategy != NULL, ("disk_create need d_strategy"));
560 	KASSERT(dp->d_name != NULL, ("disk_create need d_name"));
561 	KASSERT(*dp->d_name != 0, ("disk_create need d_name"));
562 	KASSERT(strlen(dp->d_name) < SPECNAMELEN - 4, ("disk name too long"));
563 	if (dp->d_devstat == NULL)
564 		dp->d_devstat = devstat_new_entry(dp->d_name, dp->d_unit,
565 		    dp->d_sectorsize, DEVSTAT_ALL_SUPPORTED,
566 		    DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
567 	dp->d_geom = NULL;
568 	g_disk_ident_adjust(dp->d_ident, sizeof(dp->d_ident));
569 	g_post_event(g_disk_create, dp, M_WAITOK, dp, NULL);
570 }
571 
572 void
573 disk_destroy(struct disk *dp)
574 {
575 
576 	g_cancel_event(dp);
577 	dp->d_destroyed = 1;
578 	if (dp->d_devstat != NULL)
579 		devstat_remove_entry(dp->d_devstat);
580 	g_post_event(g_disk_destroy, dp, M_WAITOK, NULL);
581 }
582 
583 void
584 disk_gone(struct disk *dp)
585 {
586 	struct g_geom *gp;
587 	struct g_provider *pp;
588 
589 	gp = dp->d_geom;
590 	if (gp != NULL)
591 		LIST_FOREACH(pp, &gp->provider, provider)
592 			g_wither_provider(pp, ENXIO);
593 }
594 
595 void
596 disk_attr_changed(struct disk *dp, const char *attr, int flag)
597 {
598 	struct g_geom *gp;
599 	struct g_provider *pp;
600 
601 	gp = dp->d_geom;
602 	if (gp != NULL)
603 		LIST_FOREACH(pp, &gp->provider, provider)
604 			(void)g_attr_changed(pp, attr, flag);
605 }
606 
607 static void
608 g_kern_disks(void *p, int flag __unused)
609 {
610 	struct sbuf *sb;
611 	struct g_geom *gp;
612 	char *sp;
613 
614 	sb = p;
615 	sp = "";
616 	g_topology_assert();
617 	LIST_FOREACH(gp, &g_disk_class.geom, geom) {
618 		sbuf_printf(sb, "%s%s", sp, gp->name);
619 		sp = " ";
620 	}
621 	sbuf_finish(sb);
622 }
623 
624 static int
625 sysctl_disks(SYSCTL_HANDLER_ARGS)
626 {
627 	int error;
628 	struct sbuf *sb;
629 
630 	sb = sbuf_new_auto();
631 	g_waitfor_event(g_kern_disks, sb, M_WAITOK, NULL);
632 	error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
633 	sbuf_delete(sb);
634 	return error;
635 }
636 
637 SYSCTL_PROC(_kern, OID_AUTO, disks,
638     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
639     sysctl_disks, "A", "names of available disks");
640 
641