xref: /freebsd/sys/geom/geom_disk.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
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/sysctl.h>
50 #include <sys/devicestat.h>
51 #include <machine/md_var.h>
52 
53 #include <sys/lock.h>
54 #include <sys/mutex.h>
55 #include <geom/geom.h>
56 #include <geom/geom_disk.h>
57 #include <geom/geom_int.h>
58 
59 #include <dev/led/led.h>
60 
61 struct g_disk_softc {
62 	struct disk		*dp;
63 	struct sysctl_ctx_list	sysctl_ctx;
64 	struct sysctl_oid	*sysctl_tree;
65 	char			led[64];
66 	uint32_t		state;
67 };
68 
69 static struct mtx g_disk_done_mtx;
70 
71 static g_access_t g_disk_access;
72 static g_init_t g_disk_init;
73 static g_fini_t g_disk_fini;
74 static g_start_t g_disk_start;
75 static g_ioctl_t g_disk_ioctl;
76 static g_dumpconf_t g_disk_dumpconf;
77 
78 static struct g_class g_disk_class = {
79 	.name = "DISK",
80 	.version = G_VERSION,
81 	.init = g_disk_init,
82 	.fini = g_disk_fini,
83 	.start = g_disk_start,
84 	.access = g_disk_access,
85 	.ioctl = g_disk_ioctl,
86 	.dumpconf = g_disk_dumpconf,
87 };
88 
89 SYSCTL_DECL(_kern_geom);
90 SYSCTL_NODE(_kern_geom, OID_AUTO, disk, CTLFLAG_RW, 0, "GEOM_DISK stuff");
91 
92 static void
93 g_disk_init(struct g_class *mp __unused)
94 {
95 
96 	mtx_init(&g_disk_done_mtx, "g_disk_done", NULL, MTX_DEF);
97 }
98 
99 static void
100 g_disk_fini(struct g_class *mp __unused)
101 {
102 
103 	mtx_destroy(&g_disk_done_mtx);
104 }
105 
106 DECLARE_GEOM_CLASS(g_disk_class, g_disk);
107 
108 static void __inline
109 g_disk_lock_giant(struct disk *dp)
110 {
111 	if (dp->d_flags & DISKFLAG_NEEDSGIANT)
112 		mtx_lock(&Giant);
113 }
114 
115 static void __inline
116 g_disk_unlock_giant(struct disk *dp)
117 {
118 	if (dp->d_flags & DISKFLAG_NEEDSGIANT)
119 		mtx_unlock(&Giant);
120 }
121 
122 static int
123 g_disk_access(struct g_provider *pp, int r, int w, int e)
124 {
125 	struct disk *dp;
126 	struct g_disk_softc *sc;
127 	int error;
128 
129 	g_trace(G_T_ACCESS, "g_disk_access(%s, %d, %d, %d)",
130 	    pp->name, r, w, e);
131 	g_topology_assert();
132 	sc = pp->geom->softc;
133 	if (sc == NULL || (dp = sc->dp) == NULL || dp->d_destroyed) {
134 		/*
135 		 * Allow decreasing access count even if disk is not
136 		 * avaliable anymore.
137 		 */
138 		if (r <= 0 && w <= 0 && e <= 0)
139 			return (0);
140 		return (ENXIO);
141 	}
142 	r += pp->acr;
143 	w += pp->acw;
144 	e += pp->ace;
145 	error = 0;
146 	if ((pp->acr + pp->acw + pp->ace) == 0 && (r + w + e) > 0) {
147 		if (dp->d_open != NULL) {
148 			g_disk_lock_giant(dp);
149 			error = dp->d_open(dp);
150 			if (bootverbose && error != 0)
151 				printf("Opened disk %s -> %d\n",
152 				    pp->name, error);
153 			g_disk_unlock_giant(dp);
154 		}
155 		pp->mediasize = dp->d_mediasize;
156 		pp->sectorsize = dp->d_sectorsize;
157 		if (dp->d_flags & DISKFLAG_CANDELETE)
158 			pp->flags |= G_PF_CANDELETE;
159 		else
160 			pp->flags &= ~G_PF_CANDELETE;
161 		pp->stripeoffset = dp->d_stripeoffset;
162 		pp->stripesize = dp->d_stripesize;
163 		dp->d_flags |= DISKFLAG_OPEN;
164 		if (dp->d_maxsize == 0) {
165 			printf("WARNING: Disk drive %s%d has no d_maxsize\n",
166 			    dp->d_name, dp->d_unit);
167 			dp->d_maxsize = DFLTPHYS;
168 		}
169 	} else if ((pp->acr + pp->acw + pp->ace) > 0 && (r + w + e) == 0) {
170 		if (dp->d_close != NULL) {
171 			g_disk_lock_giant(dp);
172 			error = dp->d_close(dp);
173 			if (error != 0)
174 				printf("Closed disk %s -> %d\n",
175 				    pp->name, error);
176 			g_disk_unlock_giant(dp);
177 		}
178 		sc->state = G_STATE_ACTIVE;
179 		if (sc->led[0] != 0)
180 			led_set(sc->led, "0");
181 		dp->d_flags &= ~DISKFLAG_OPEN;
182 	}
183 	return (error);
184 }
185 
186 static void
187 g_disk_kerneldump(struct bio *bp, struct disk *dp)
188 {
189 	struct g_kerneldump *gkd;
190 	struct g_geom *gp;
191 
192 	gkd = (struct g_kerneldump*)bp->bio_data;
193 	gp = bp->bio_to->geom;
194 	g_trace(G_T_TOPOLOGY, "g_disk_kernedump(%s, %jd, %jd)",
195 		gp->name, (intmax_t)gkd->offset, (intmax_t)gkd->length);
196 	if (dp->d_dump == NULL) {
197 		g_io_deliver(bp, ENODEV);
198 		return;
199 	}
200 	gkd->di.dumper = dp->d_dump;
201 	gkd->di.priv = dp;
202 	gkd->di.blocksize = dp->d_sectorsize;
203 	gkd->di.maxiosize = dp->d_maxsize;
204 	gkd->di.mediaoffset = gkd->offset;
205 	if ((gkd->offset + gkd->length) > dp->d_mediasize)
206 		gkd->length = dp->d_mediasize - gkd->offset;
207 	gkd->di.mediasize = gkd->length;
208 	g_io_deliver(bp, 0);
209 }
210 
211 static void
212 g_disk_setstate(struct bio *bp, struct g_disk_softc *sc)
213 {
214 	const char *cmd;
215 
216 	memcpy(&sc->state, bp->bio_data, sizeof(sc->state));
217 	if (sc->led[0] != 0) {
218 		switch (sc->state) {
219 		case G_STATE_FAILED:
220 			cmd = "1";
221 			break;
222 		case G_STATE_REBUILD:
223 			cmd = "f5";
224 			break;
225 		case G_STATE_RESYNC:
226 			cmd = "f1";
227 			break;
228 		default:
229 			cmd = "0";
230 			break;
231 		}
232 		led_set(sc->led, cmd);
233 	}
234 	g_io_deliver(bp, 0);
235 }
236 
237 static void
238 g_disk_done(struct bio *bp)
239 {
240 	struct bio *bp2;
241 	struct disk *dp;
242 	struct g_disk_softc *sc;
243 
244 	/* See "notes" for why we need a mutex here */
245 	/* XXX: will witness accept a mix of Giant/unGiant drivers here ? */
246 	mtx_lock(&g_disk_done_mtx);
247 	bp->bio_completed = bp->bio_length - bp->bio_resid;
248 
249 	bp2 = bp->bio_parent;
250 	if (bp2->bio_error == 0)
251 		bp2->bio_error = bp->bio_error;
252 	bp2->bio_completed += bp->bio_completed;
253 	if ((bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_DELETE)) &&
254 	    (sc = bp2->bio_to->geom->softc) &&
255 	    (dp = sc->dp)) {
256 		devstat_end_transaction_bio(dp->d_devstat, bp);
257 	}
258 	g_destroy_bio(bp);
259 	bp2->bio_inbed++;
260 	if (bp2->bio_children == bp2->bio_inbed) {
261 		bp2->bio_resid = bp2->bio_bcount - bp2->bio_completed;
262 		g_io_deliver(bp2, bp2->bio_error);
263 	}
264 	mtx_unlock(&g_disk_done_mtx);
265 }
266 
267 static int
268 g_disk_ioctl(struct g_provider *pp, u_long cmd, void * data, int fflag, struct thread *td)
269 {
270 	struct g_geom *gp;
271 	struct disk *dp;
272 	struct g_disk_softc *sc;
273 	int error;
274 
275 	gp = pp->geom;
276 	sc = gp->softc;
277 	dp = sc->dp;
278 
279 	if (dp->d_ioctl == NULL)
280 		return (ENOIOCTL);
281 	g_disk_lock_giant(dp);
282 	error = dp->d_ioctl(dp, cmd, data, fflag, td);
283 	g_disk_unlock_giant(dp);
284 	return(error);
285 }
286 
287 static void
288 g_disk_start(struct bio *bp)
289 {
290 	struct bio *bp2, *bp3;
291 	struct disk *dp;
292 	struct g_disk_softc *sc;
293 	int error;
294 	off_t off;
295 
296 	sc = bp->bio_to->geom->softc;
297 	if (sc == NULL || (dp = sc->dp) == NULL || dp->d_destroyed) {
298 		g_io_deliver(bp, ENXIO);
299 		return;
300 	}
301 	error = EJUSTRETURN;
302 	switch(bp->bio_cmd) {
303 	case BIO_DELETE:
304 		if (!(dp->d_flags & DISKFLAG_CANDELETE)) {
305 			error = 0;
306 			break;
307 		}
308 		/* fall-through */
309 	case BIO_READ:
310 	case BIO_WRITE:
311 		off = 0;
312 		bp3 = NULL;
313 		bp2 = g_clone_bio(bp);
314 		if (bp2 == NULL) {
315 			error = ENOMEM;
316 			break;
317 		}
318 		do {
319 			bp2->bio_offset += off;
320 			bp2->bio_length -= off;
321 			bp2->bio_data += off;
322 			if (bp2->bio_length > dp->d_maxsize) {
323 				/*
324 				 * XXX: If we have a stripesize we should really
325 				 * use it here.
326 				 */
327 				bp2->bio_length = dp->d_maxsize;
328 				off += dp->d_maxsize;
329 				/*
330 				 * To avoid a race, we need to grab the next bio
331 				 * before we schedule this one.  See "notes".
332 				 */
333 				bp3 = g_clone_bio(bp);
334 				if (bp3 == NULL)
335 					bp->bio_error = ENOMEM;
336 			}
337 			bp2->bio_done = g_disk_done;
338 			bp2->bio_pblkno = bp2->bio_offset / dp->d_sectorsize;
339 			bp2->bio_bcount = bp2->bio_length;
340 			bp2->bio_disk = dp;
341 			devstat_start_transaction_bio(dp->d_devstat, bp2);
342 			g_disk_lock_giant(dp);
343 			dp->d_strategy(bp2);
344 			g_disk_unlock_giant(dp);
345 			bp2 = bp3;
346 			bp3 = NULL;
347 		} while (bp2 != NULL);
348 		break;
349 	case BIO_GETATTR:
350 		if (g_handleattr_int(bp, "GEOM::candelete",
351 		    (dp->d_flags & DISKFLAG_CANDELETE) != 0))
352 			break;
353 		else if (g_handleattr_int(bp, "GEOM::fwsectors",
354 		    dp->d_fwsectors))
355 			break;
356 		else if (g_handleattr_int(bp, "GEOM::fwheads", dp->d_fwheads))
357 			break;
358 		else if (g_handleattr_off_t(bp, "GEOM::frontstuff", 0))
359 			break;
360 		else if (g_handleattr_str(bp, "GEOM::ident", dp->d_ident))
361 			break;
362 		else if (g_handleattr(bp, "GEOM::hba_vendor",
363 		    &dp->d_hba_vendor, 2))
364 			break;
365 		else if (g_handleattr(bp, "GEOM::hba_device",
366 		    &dp->d_hba_device, 2))
367 			break;
368 		else if (g_handleattr(bp, "GEOM::hba_subvendor",
369 		    &dp->d_hba_subvendor, 2))
370 			break;
371 		else if (g_handleattr(bp, "GEOM::hba_subdevice",
372 		    &dp->d_hba_subdevice, 2))
373 			break;
374 		else if (!strcmp(bp->bio_attribute, "GEOM::kerneldump"))
375 			g_disk_kerneldump(bp, dp);
376 		else if (!strcmp(bp->bio_attribute, "GEOM::setstate"))
377 			g_disk_setstate(bp, sc);
378 		else
379 			error = ENOIOCTL;
380 		break;
381 	case BIO_FLUSH:
382 		g_trace(G_T_TOPOLOGY, "g_disk_flushcache(%s)",
383 		    bp->bio_to->name);
384 		if (!(dp->d_flags & DISKFLAG_CANFLUSHCACHE)) {
385 			g_io_deliver(bp, ENODEV);
386 			return;
387 		}
388 		bp2 = g_clone_bio(bp);
389 		if (bp2 == NULL) {
390 			g_io_deliver(bp, ENOMEM);
391 			return;
392 		}
393 		bp2->bio_done = g_disk_done;
394 		bp2->bio_disk = dp;
395 		g_disk_lock_giant(dp);
396 		dp->d_strategy(bp2);
397 		g_disk_unlock_giant(dp);
398 		break;
399 	default:
400 		error = EOPNOTSUPP;
401 		break;
402 	}
403 	if (error != EJUSTRETURN)
404 		g_io_deliver(bp, error);
405 	return;
406 }
407 
408 static void
409 g_disk_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp)
410 {
411 	struct disk *dp;
412 	struct g_disk_softc *sc;
413 
414 	sc = gp->softc;
415 	if (sc == NULL || (dp = sc->dp) == NULL)
416 		return;
417 	if (indent == NULL) {
418 		sbuf_printf(sb, " hd %u", dp->d_fwheads);
419 		sbuf_printf(sb, " sc %u", dp->d_fwsectors);
420 		return;
421 	}
422 	if (pp != NULL) {
423 		sbuf_printf(sb, "%s<fwheads>%u</fwheads>\n",
424 		    indent, dp->d_fwheads);
425 		sbuf_printf(sb, "%s<fwsectors>%u</fwsectors>\n",
426 		    indent, dp->d_fwsectors);
427 		sbuf_printf(sb, "%s<ident>%s</ident>\n", indent, dp->d_ident);
428 		sbuf_printf(sb, "%s<descr>%s</descr>\n", indent, dp->d_descr);
429 	}
430 }
431 
432 static void
433 g_disk_create(void *arg, int flag)
434 {
435 	struct g_geom *gp;
436 	struct g_provider *pp;
437 	struct disk *dp;
438 	struct g_disk_softc *sc;
439 	char tmpstr[80];
440 
441 	if (flag == EV_CANCEL)
442 		return;
443 	g_topology_assert();
444 	dp = arg;
445 	sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
446 	sc->dp = dp;
447 	gp = g_new_geomf(&g_disk_class, "%s%d", dp->d_name, dp->d_unit);
448 	gp->softc = sc;
449 	pp = g_new_providerf(gp, "%s", gp->name);
450 	pp->mediasize = dp->d_mediasize;
451 	pp->sectorsize = dp->d_sectorsize;
452 	if (dp->d_flags & DISKFLAG_CANDELETE)
453 		pp->flags |= G_PF_CANDELETE;
454 	pp->stripeoffset = dp->d_stripeoffset;
455 	pp->stripesize = dp->d_stripesize;
456 	if (bootverbose)
457 		printf("GEOM: new disk %s\n", gp->name);
458 	sysctl_ctx_init(&sc->sysctl_ctx);
459 	snprintf(tmpstr, sizeof(tmpstr), "GEOM disk %s", gp->name);
460 	sc->sysctl_tree = SYSCTL_ADD_NODE(&sc->sysctl_ctx,
461 		SYSCTL_STATIC_CHILDREN(_kern_geom_disk), OID_AUTO, gp->name,
462 		CTLFLAG_RD, 0, tmpstr);
463 	if (sc->sysctl_tree != NULL) {
464 		snprintf(tmpstr, sizeof(tmpstr),
465 		    "kern.geom.disk.%s.led", gp->name);
466 		TUNABLE_STR_FETCH(tmpstr, sc->led, sizeof(sc->led));
467 		SYSCTL_ADD_STRING(&sc->sysctl_ctx,
468 		    SYSCTL_CHILDREN(sc->sysctl_tree), OID_AUTO, "led",
469 		    CTLFLAG_RW | CTLFLAG_TUN, sc->led, sizeof(sc->led),
470 		    "LED name");
471 	}
472 	pp->private = sc;
473 	dp->d_geom = gp;
474 	g_error_provider(pp, 0);
475 }
476 
477 static void
478 g_disk_destroy(void *ptr, int flag)
479 {
480 	struct disk *dp;
481 	struct g_geom *gp;
482 	struct g_disk_softc *sc;
483 
484 	g_topology_assert();
485 	dp = ptr;
486 	gp = dp->d_geom;
487 	if (gp != NULL) {
488 		sc = gp->softc;
489 		if (sc->sysctl_tree != NULL) {
490 			sysctl_ctx_free(&sc->sysctl_ctx);
491 			sc->sysctl_tree = NULL;
492 		}
493 		if (sc->led[0] != 0) {
494 			led_set(sc->led, "0");
495 			sc->led[0] = 0;
496 		}
497 		g_free(sc);
498 		gp->softc = NULL;
499 		g_wither_geom(gp, ENXIO);
500 	}
501 	g_free(dp);
502 }
503 
504 /*
505  * We only allow printable characters in disk ident,
506  * the rest is converted to 'x<HH>'.
507  */
508 static void
509 g_disk_ident_adjust(char *ident, size_t size)
510 {
511 	char *p, tmp[4], newid[DISK_IDENT_SIZE];
512 
513 	newid[0] = '\0';
514 	for (p = ident; *p != '\0'; p++) {
515 		if (isprint(*p)) {
516 			tmp[0] = *p;
517 			tmp[1] = '\0';
518 		} else {
519 			snprintf(tmp, sizeof(tmp), "x%02hhx",
520 			    *(unsigned char *)p);
521 		}
522 		if (strlcat(newid, tmp, sizeof(newid)) >= sizeof(newid))
523 			break;
524 	}
525 	bzero(ident, size);
526 	strlcpy(ident, newid, size);
527 }
528 
529 struct disk *
530 disk_alloc()
531 {
532 	struct disk *dp;
533 
534 	dp = g_malloc(sizeof *dp, M_WAITOK | M_ZERO);
535 	return (dp);
536 }
537 
538 void
539 disk_create(struct disk *dp, int version)
540 {
541 	if (version != DISK_VERSION_00 && version != DISK_VERSION_01) {
542 		printf("WARNING: Attempt to add disk %s%d %s",
543 		    dp->d_name, dp->d_unit,
544 		    " using incompatible ABI version of disk(9)\n");
545 		printf("WARNING: Ignoring disk %s%d\n",
546 		    dp->d_name, dp->d_unit);
547 		return;
548 	}
549 	KASSERT(dp->d_strategy != NULL, ("disk_create need d_strategy"));
550 	KASSERT(dp->d_name != NULL, ("disk_create need d_name"));
551 	KASSERT(*dp->d_name != 0, ("disk_create need d_name"));
552 	KASSERT(strlen(dp->d_name) < SPECNAMELEN - 4, ("disk name too long"));
553 	if (dp->d_devstat == NULL)
554 		dp->d_devstat = devstat_new_entry(dp->d_name, dp->d_unit,
555 		    dp->d_sectorsize, DEVSTAT_ALL_SUPPORTED,
556 		    DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
557 	dp->d_geom = NULL;
558 	g_disk_ident_adjust(dp->d_ident, sizeof(dp->d_ident));
559 	g_post_event(g_disk_create, dp, M_WAITOK, dp, NULL);
560 }
561 
562 void
563 disk_destroy(struct disk *dp)
564 {
565 
566 	g_cancel_event(dp);
567 	dp->d_destroyed = 1;
568 	if (dp->d_devstat != NULL)
569 		devstat_remove_entry(dp->d_devstat);
570 	g_post_event(g_disk_destroy, dp, M_WAITOK, NULL);
571 }
572 
573 void
574 disk_gone(struct disk *dp)
575 {
576 	struct g_geom *gp;
577 	struct g_provider *pp;
578 
579 	gp = dp->d_geom;
580 	if (gp != NULL)
581 		LIST_FOREACH(pp, &gp->provider, provider)
582 			g_wither_provider(pp, ENXIO);
583 }
584 
585 static void
586 g_kern_disks(void *p, int flag __unused)
587 {
588 	struct sbuf *sb;
589 	struct g_geom *gp;
590 	char *sp;
591 
592 	sb = p;
593 	sp = "";
594 	g_topology_assert();
595 	LIST_FOREACH(gp, &g_disk_class.geom, geom) {
596 		sbuf_printf(sb, "%s%s", sp, gp->name);
597 		sp = " ";
598 	}
599 	sbuf_finish(sb);
600 }
601 
602 static int
603 sysctl_disks(SYSCTL_HANDLER_ARGS)
604 {
605 	int error;
606 	struct sbuf *sb;
607 
608 	sb = sbuf_new_auto();
609 	g_waitfor_event(g_kern_disks, sb, M_WAITOK, NULL);
610 	error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
611 	sbuf_delete(sb);
612 	return error;
613 }
614 
615 SYSCTL_PROC(_kern, OID_AUTO, disks,
616     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
617     sysctl_disks, "A", "names of available disks");
618 
619