xref: /freebsd/sys/geom/multipath/g_multipath.c (revision 2dd83b3f0507fc7bc64b908fb88f285a3b9663c8)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2011-2013 Alexander Motin <mav@FreeBSD.org>
5  * Copyright (c) 2006-2007 Matthew Jacob <mjacob@FreeBSD.org>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 /*
30  * Based upon work by Pawel Jakub Dawidek <pjd@FreeBSD.org> for all of the
31  * fine geom examples, and by Poul Henning Kamp <phk@FreeBSD.org> for GEOM
32  * itself, all of which is most gratefully acknowledged.
33  */
34 
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/kernel.h>
40 #include <sys/module.h>
41 #include <sys/limits.h>
42 #include <sys/lock.h>
43 #include <sys/mutex.h>
44 #include <sys/bio.h>
45 #include <sys/sbuf.h>
46 #include <sys/sdt.h>
47 #include <sys/sysctl.h>
48 #include <sys/kthread.h>
49 #include <sys/malloc.h>
50 #include <geom/geom.h>
51 #include <geom/multipath/g_multipath.h>
52 
53 FEATURE(geom_multipath, "GEOM multipath support");
54 
55 SYSCTL_DECL(_kern_geom);
56 static SYSCTL_NODE(_kern_geom, OID_AUTO, multipath,
57     CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
58     "GEOM_MULTIPATH tunables");
59 static u_int g_multipath_debug = 0;
60 SYSCTL_UINT(_kern_geom_multipath, OID_AUTO, debug, CTLFLAG_RW,
61     &g_multipath_debug, 0, "Debug level");
62 static u_int g_multipath_exclusive = 1;
63 SYSCTL_UINT(_kern_geom_multipath, OID_AUTO, exclusive, CTLFLAG_RW,
64     &g_multipath_exclusive, 0, "Exclusively open providers");
65 
66 SDT_PROVIDER_DECLARE(geom);
67 SDT_PROBE_DEFINE2(geom, multipath, config, restore, "char*", "char*");
68 SDT_PROBE_DEFINE2(geom, multipath, config, remove, "char*", "char*");
69 SDT_PROBE_DEFINE2(geom, multipath, config, disconnect, "char*", "char*");
70 SDT_PROBE_DEFINE3(geom, multipath, config, fail, "char*", "char*", "int");
71 SDT_PROBE_DEFINE2(geom, multipath, config, taste, "char*", "char*");
72 SDT_PROBE_DEFINE2(geom, multipath, io, restart, "struct bio*", "struct bio*");
73 
74 static enum {
75 	GKT_NIL,
76 	GKT_RUN,
77 	GKT_DIE
78 } g_multipath_kt_state;
79 static struct bio_queue_head gmtbq;
80 static struct mtx gmtbq_mtx;
81 
82 static int g_multipath_read_metadata(struct g_consumer *cp,
83     struct g_multipath_metadata *md);
84 static int g_multipath_write_metadata(struct g_consumer *cp,
85     struct g_multipath_metadata *md);
86 
87 static void g_multipath_orphan(struct g_consumer *);
88 static void g_multipath_resize(struct g_consumer *);
89 static void g_multipath_start(struct bio *);
90 static void g_multipath_done(struct bio *);
91 static void g_multipath_done_error(struct bio *);
92 static void g_multipath_kt(void *);
93 
94 static int g_multipath_destroy(struct g_geom *);
95 static int
96 g_multipath_destroy_geom(struct gctl_req *, struct g_class *, struct g_geom *);
97 
98 static struct g_geom *g_multipath_find_geom(struct g_class *, const char *);
99 static int g_multipath_rotate(struct g_geom *);
100 
101 static g_taste_t g_multipath_taste;
102 static g_ctl_req_t g_multipath_config;
103 static g_init_t g_multipath_init;
104 static g_fini_t g_multipath_fini;
105 static g_dumpconf_t g_multipath_dumpconf;
106 
107 struct g_class g_multipath_class = {
108 	.name		= G_MULTIPATH_CLASS_NAME,
109 	.version	= G_VERSION,
110 	.ctlreq		= g_multipath_config,
111 	.taste		= g_multipath_taste,
112 	.destroy_geom	= g_multipath_destroy_geom,
113 	.init		= g_multipath_init,
114 	.fini		= g_multipath_fini
115 };
116 
117 #define	MP_FAIL		0x00000001
118 #define	MP_LOST		0x00000002
119 #define	MP_NEW		0x00000004
120 #define	MP_POSTED	0x00000008
121 #define	MP_BAD		(MP_FAIL | MP_LOST | MP_NEW)
122 #define	MP_WITHER	0x00000010
123 #define	MP_IDLE		0x00000020
124 #define	MP_IDLE_MASK	0xffffffe0
125 
126 static int
127 g_multipath_good(struct g_geom *gp)
128 {
129 	struct g_consumer *cp;
130 	int n = 0;
131 
132 	LIST_FOREACH(cp, &gp->consumer, consumer) {
133 		if ((cp->index & MP_BAD) == 0)
134 			n++;
135 	}
136 	return (n);
137 }
138 
139 static void
140 g_multipath_fault(struct g_consumer *cp, int cause)
141 {
142 	struct g_multipath_softc *sc;
143 	struct g_consumer *lcp;
144 	struct g_geom *gp;
145 
146 	gp = cp->geom;
147 	sc = gp->softc;
148 	cp->index |= cause;
149 	if (g_multipath_good(gp) == 0 && sc->sc_ndisks > 0) {
150 		LIST_FOREACH(lcp, &gp->consumer, consumer) {
151 			if (lcp->provider == NULL ||
152 			    (lcp->index & (MP_LOST | MP_NEW)))
153 				continue;
154 			if (sc->sc_ndisks > 1 && lcp == cp)
155 				continue;
156 			printf("GEOM_MULTIPATH: "
157 			    "all paths in %s were marked FAIL, restore %s\n",
158 			    sc->sc_name, lcp->provider->name);
159 			SDT_PROBE2(geom, multipath, config, restore,
160 			    sc->sc_name, lcp->provider->name);
161 			lcp->index &= ~MP_FAIL;
162 		}
163 	}
164 	if (cp != sc->sc_active)
165 		return;
166 	sc->sc_active = NULL;
167 	LIST_FOREACH(lcp, &gp->consumer, consumer) {
168 		if ((lcp->index & MP_BAD) == 0) {
169 			sc->sc_active = lcp;
170 			break;
171 		}
172 	}
173 	if (sc->sc_active == NULL) {
174 		printf("GEOM_MULTIPATH: out of providers for %s\n",
175 		    sc->sc_name);
176 	} else if (sc->sc_active_active != 1) {
177 		printf("GEOM_MULTIPATH: %s is now active path in %s\n",
178 		    sc->sc_active->provider->name, sc->sc_name);
179 	}
180 }
181 
182 static struct g_consumer *
183 g_multipath_choose(struct g_geom *gp, struct bio *bp)
184 {
185 	struct g_multipath_softc *sc;
186 	struct g_consumer *best, *cp;
187 
188 	sc = gp->softc;
189 	if (sc->sc_active_active == 0 ||
190 	    (sc->sc_active_active == 2 && bp->bio_cmd != BIO_READ))
191 		return (sc->sc_active);
192 	best = NULL;
193 	LIST_FOREACH(cp, &gp->consumer, consumer) {
194 		if (cp->index & MP_BAD)
195 			continue;
196 		cp->index += MP_IDLE;
197 		if (best == NULL || cp->private < best->private ||
198 		    (cp->private == best->private && cp->index > best->index))
199 			best = cp;
200 	}
201 	if (best != NULL)
202 		best->index &= ~MP_IDLE_MASK;
203 	return (best);
204 }
205 
206 static void
207 g_mpd(void *arg, int flags __unused)
208 {
209 	struct g_geom *gp;
210 	struct g_multipath_softc *sc;
211 	struct g_consumer *cp;
212 	int w;
213 
214 	g_topology_assert();
215 	cp = arg;
216 	gp = cp->geom;
217 	if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0) {
218 		w = cp->acw;
219 		g_access(cp, -cp->acr, -cp->acw, -cp->ace);
220 		if (w > 0 && cp->provider != NULL &&
221 		    (cp->provider->geom->flags & G_GEOM_WITHER) == 0) {
222 			cp->index |= MP_WITHER;
223 			g_post_event(g_mpd, cp, M_WAITOK, NULL);
224 			return;
225 		}
226 	}
227 	sc = gp->softc;
228 	mtx_lock(&sc->sc_mtx);
229 	if (cp->provider) {
230 		printf("GEOM_MULTIPATH: %s removed from %s\n",
231 		    cp->provider->name, gp->name);
232 		SDT_PROBE2(geom, multipath, config, remove,
233 		    gp->name, cp->provider->name);
234 		g_detach(cp);
235 	}
236 	g_destroy_consumer(cp);
237 	mtx_unlock(&sc->sc_mtx);
238 	if (LIST_EMPTY(&gp->consumer))
239 		g_multipath_destroy(gp);
240 }
241 
242 static void
243 g_multipath_orphan(struct g_consumer *cp)
244 {
245 	struct g_multipath_softc *sc;
246 	uintptr_t *cnt;
247 
248 	g_topology_assert();
249 	printf("GEOM_MULTIPATH: %s in %s was disconnected\n",
250 	    cp->provider->name, cp->geom->name);
251 	SDT_PROBE2(geom, multipath, config, disconnect,
252 	    cp->geom->name, cp->provider->name);
253 	sc = cp->geom->softc;
254 	cnt = (uintptr_t *)&cp->private;
255 	mtx_lock(&sc->sc_mtx);
256 	sc->sc_ndisks--;
257 	g_multipath_fault(cp, MP_LOST);
258 	if (*cnt == 0 && (cp->index & MP_POSTED) == 0) {
259 		cp->index |= MP_POSTED;
260 		mtx_unlock(&sc->sc_mtx);
261 		g_mpd(cp, 0);
262 	} else
263 		mtx_unlock(&sc->sc_mtx);
264 }
265 
266 static void
267 g_multipath_resize(struct g_consumer *cp)
268 {
269 	struct g_multipath_softc *sc;
270 	struct g_geom *gp;
271 	struct g_consumer *cp1;
272 	struct g_provider *pp;
273 	struct g_multipath_metadata md;
274 	off_t size, psize, ssize;
275 	int error;
276 
277 	g_topology_assert();
278 
279 	gp = cp->geom;
280 	pp = cp->provider;
281 	sc = gp->softc;
282 
283 	if (sc->sc_stopping)
284 		return;
285 
286 	if (pp->mediasize < sc->sc_size) {
287 		size = pp->mediasize;
288 		ssize = pp->sectorsize;
289 	} else {
290 		size = ssize = OFF_MAX;
291 		mtx_lock(&sc->sc_mtx);
292 		LIST_FOREACH(cp1, &gp->consumer, consumer) {
293 			pp = cp1->provider;
294 			if (pp == NULL)
295 				continue;
296 			if (pp->mediasize < size) {
297 				size = pp->mediasize;
298 				ssize = pp->sectorsize;
299 			}
300 		}
301 		mtx_unlock(&sc->sc_mtx);
302 		if (size == OFF_MAX || size == sc->sc_size)
303 			return;
304 	}
305 	psize = size - ((sc->sc_uuid[0] != 0) ? ssize : 0);
306 	printf("GEOM_MULTIPATH: %s size changed from %jd to %jd\n",
307 	    sc->sc_name, sc->sc_pp->mediasize, psize);
308 	if (sc->sc_uuid[0] != 0 && size < sc->sc_size) {
309 		error = g_multipath_read_metadata(cp, &md);
310 		if (error ||
311 		    (strcmp(md.md_magic, G_MULTIPATH_MAGIC) != 0) ||
312 		    (memcmp(md.md_uuid, sc->sc_uuid, sizeof(sc->sc_uuid)) != 0) ||
313 		    (strcmp(md.md_name, sc->sc_name) != 0) ||
314 		    (md.md_size != 0 && md.md_size != size) ||
315 		    (md.md_sectorsize != 0 && md.md_sectorsize != ssize)) {
316 			g_multipath_destroy(gp);
317 			return;
318 		}
319 	}
320 	sc->sc_size = size;
321 	g_resize_provider(sc->sc_pp, psize);
322 
323 	if (sc->sc_uuid[0] != 0) {
324 		pp = cp->provider;
325 		strlcpy(md.md_magic, G_MULTIPATH_MAGIC, sizeof(md.md_magic));
326 		memcpy(md.md_uuid, sc->sc_uuid, sizeof (sc->sc_uuid));
327 		strlcpy(md.md_name, sc->sc_name, sizeof(md.md_name));
328 		md.md_version = G_MULTIPATH_VERSION;
329 		md.md_size = size;
330 		md.md_sectorsize = ssize;
331 		md.md_active_active = sc->sc_active_active;
332 		error = g_multipath_write_metadata(cp, &md);
333 		if (error != 0)
334 			printf("GEOM_MULTIPATH: Can't update metadata on %s "
335 			    "(%d)\n", pp->name, error);
336 	}
337 }
338 
339 static void
340 g_multipath_start(struct bio *bp)
341 {
342 	struct g_multipath_softc *sc;
343 	struct g_geom *gp;
344 	struct g_consumer *cp;
345 	struct bio *cbp;
346 	uintptr_t *cnt;
347 
348 	gp = bp->bio_to->geom;
349 	sc = gp->softc;
350 	KASSERT(sc != NULL, ("NULL sc"));
351 	cbp = g_clone_bio(bp);
352 	if (cbp == NULL) {
353 		g_io_deliver(bp, ENOMEM);
354 		return;
355 	}
356 	mtx_lock(&sc->sc_mtx);
357 	cp = g_multipath_choose(gp, bp);
358 	if (cp == NULL) {
359 		mtx_unlock(&sc->sc_mtx);
360 		g_destroy_bio(cbp);
361 		g_io_deliver(bp, ENXIO);
362 		return;
363 	}
364 	if ((uintptr_t)bp->bio_driver1 < sc->sc_ndisks)
365 		bp->bio_driver1 = (void *)(uintptr_t)sc->sc_ndisks;
366 	cnt = (uintptr_t *)&cp->private;
367 	(*cnt)++;
368 	mtx_unlock(&sc->sc_mtx);
369 	cbp->bio_done = g_multipath_done;
370 	g_io_request(cbp, cp);
371 }
372 
373 static void
374 g_multipath_done(struct bio *bp)
375 {
376 	struct g_multipath_softc *sc;
377 	struct g_consumer *cp;
378 	uintptr_t *cnt;
379 
380 	if (bp->bio_error == ENXIO || bp->bio_error == EIO) {
381 		mtx_lock(&gmtbq_mtx);
382 		bioq_insert_tail(&gmtbq, bp);
383 		mtx_unlock(&gmtbq_mtx);
384 		wakeup(&g_multipath_kt_state);
385 	} else {
386 		cp = bp->bio_from;
387 		sc = cp->geom->softc;
388 		cnt = (uintptr_t *)&cp->private;
389 		mtx_lock(&sc->sc_mtx);
390 		(*cnt)--;
391 		if (*cnt == 0 && (cp->index & MP_LOST)) {
392 			if (g_post_event(g_mpd, cp, M_NOWAIT, NULL) == 0)
393 				cp->index |= MP_POSTED;
394 			mtx_unlock(&sc->sc_mtx);
395 		} else
396 			mtx_unlock(&sc->sc_mtx);
397 		if (bp->bio_error == 0 &&
398 			bp->bio_cmd == BIO_GETATTR &&
399 			!strcmp(bp->bio_attribute, "GEOM::physpath"))
400 		{
401 			strlcat(bp->bio_data, "/mp", bp->bio_length);
402 		}
403 		g_std_done(bp);
404 	}
405 }
406 
407 static void
408 g_multipath_done_error(struct bio *bp)
409 {
410 	struct bio *pbp;
411 	struct g_geom *gp;
412 	struct g_multipath_softc *sc;
413 	struct g_consumer *cp;
414 	struct g_provider *pp;
415 	uintptr_t *cnt;
416 
417 	/*
418 	 * If we had a failure, we have to check first to see
419 	 * whether the consumer it failed on was the currently
420 	 * active consumer (i.e., this is the first in perhaps
421 	 * a number of failures). If so, we then switch consumers
422 	 * to the next available consumer.
423 	 */
424 
425 	pbp = bp->bio_parent;
426 	gp = pbp->bio_to->geom;
427 	sc = gp->softc;
428 	cp = bp->bio_from;
429 	pp = cp->provider;
430 	cnt = (uintptr_t *)&cp->private;
431 
432 	mtx_lock(&sc->sc_mtx);
433 	if ((cp->index & MP_FAIL) == 0) {
434 		printf("GEOM_MULTIPATH: Error %d, %s in %s marked FAIL\n",
435 		    bp->bio_error, pp->name, sc->sc_name);
436 		SDT_PROBE3(geom, multipath, config, fail,
437 		    sc->sc_name, pp->name, bp->bio_error);
438 		g_multipath_fault(cp, MP_FAIL);
439 	}
440 	(*cnt)--;
441 	if (*cnt == 0 && (cp->index & (MP_LOST | MP_POSTED)) == MP_LOST) {
442 		cp->index |= MP_POSTED;
443 		mtx_unlock(&sc->sc_mtx);
444 		g_post_event(g_mpd, cp, M_WAITOK, NULL);
445 	} else
446 		mtx_unlock(&sc->sc_mtx);
447 
448 	/*
449 	 * If we can fruitfully restart the I/O, do so.
450 	 */
451 	if (pbp->bio_children < (uintptr_t)pbp->bio_driver1) {
452 		pbp->bio_inbed++;
453 		SDT_PROBE2(geom, multipath, io, restart, bp, pbp);
454 		g_destroy_bio(bp);
455 		g_multipath_start(pbp);
456 	} else {
457 		g_std_done(bp);
458 	}
459 }
460 
461 static void
462 g_multipath_kt(void *arg)
463 {
464 
465 	g_multipath_kt_state = GKT_RUN;
466 	mtx_lock(&gmtbq_mtx);
467 	while (g_multipath_kt_state == GKT_RUN) {
468 		for (;;) {
469 			struct bio *bp;
470 
471 			bp = bioq_takefirst(&gmtbq);
472 			if (bp == NULL)
473 				break;
474 			mtx_unlock(&gmtbq_mtx);
475 			g_multipath_done_error(bp);
476 			mtx_lock(&gmtbq_mtx);
477 		}
478 		if (g_multipath_kt_state != GKT_RUN)
479 			break;
480 		msleep(&g_multipath_kt_state, &gmtbq_mtx, PRIBIO,
481 		    "gkt:wait", 0);
482 	}
483 	mtx_unlock(&gmtbq_mtx);
484 	wakeup(&g_multipath_kt_state);
485 	kproc_exit(0);
486 }
487 
488 static int
489 g_multipath_access(struct g_provider *pp, int dr, int dw, int de)
490 {
491 	struct g_geom *gp;
492 	struct g_consumer *cp, *badcp = NULL;
493 	struct g_multipath_softc *sc;
494 	int error;
495 
496 	gp = pp->geom;
497 
498 	/* Error used if we have no valid consumers. */
499 	error = (dr > 0 || dw > 0 || de > 0) ? ENXIO : 0;
500 
501 	LIST_FOREACH(cp, &gp->consumer, consumer) {
502 		if (cp->index & MP_WITHER)
503 			continue;
504 
505 		error = g_access(cp, dr, dw, de);
506 		if (error) {
507 			badcp = cp;
508 			goto fail;
509 		}
510 	}
511 
512 	if (error != 0)
513 		return (error);
514 
515 	sc = gp->softc;
516 	sc->sc_opened += dr + dw + de;
517 	if (sc->sc_stopping && sc->sc_opened == 0)
518 		g_multipath_destroy(gp);
519 
520 	return (0);
521 
522 fail:
523 	LIST_FOREACH(cp, &gp->consumer, consumer) {
524 		if (cp == badcp)
525 			break;
526 		if (cp->index & MP_WITHER)
527 			continue;
528 
529 		(void) g_access(cp, -dr, -dw, -de);
530 	}
531 	return (error);
532 }
533 
534 static struct g_geom *
535 g_multipath_create(struct g_class *mp, struct g_multipath_metadata *md)
536 {
537 	struct g_multipath_softc *sc;
538 	struct g_geom *gp;
539 	struct g_provider *pp;
540 
541 	g_topology_assert();
542 
543 	LIST_FOREACH(gp, &mp->geom, geom) {
544 		sc = gp->softc;
545 		if (sc == NULL || sc->sc_stopping)
546 			continue;
547 		if (strcmp(gp->name, md->md_name) == 0) {
548 			printf("GEOM_MULTIPATH: name %s already exists\n",
549 			    md->md_name);
550 			return (NULL);
551 		}
552 	}
553 
554 	gp = g_new_geomf(mp, "%s", md->md_name);
555 	sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
556 	mtx_init(&sc->sc_mtx, "multipath", NULL, MTX_DEF);
557 	memcpy(sc->sc_uuid, md->md_uuid, sizeof (sc->sc_uuid));
558 	memcpy(sc->sc_name, md->md_name, sizeof (sc->sc_name));
559 	sc->sc_active_active = md->md_active_active;
560 	sc->sc_size = md->md_size;
561 	gp->softc = sc;
562 	gp->start = g_multipath_start;
563 	gp->orphan = g_multipath_orphan;
564 	gp->resize = g_multipath_resize;
565 	gp->access = g_multipath_access;
566 	gp->dumpconf = g_multipath_dumpconf;
567 
568 	pp = g_new_providerf(gp, "multipath/%s", md->md_name);
569 	pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE;
570 	if (md->md_size != 0) {
571 		pp->mediasize = md->md_size -
572 		    ((md->md_uuid[0] != 0) ? md->md_sectorsize : 0);
573 		pp->sectorsize = md->md_sectorsize;
574 	}
575 	sc->sc_pp = pp;
576 	g_error_provider(pp, 0);
577 	printf("GEOM_MULTIPATH: %s created\n", gp->name);
578 	return (gp);
579 }
580 
581 static int
582 g_multipath_add_disk(struct g_geom *gp, struct g_provider *pp)
583 {
584 	struct g_multipath_softc *sc;
585 	struct g_consumer *cp;
586 	int error, acr, acw, ace;
587 
588 	g_topology_assert();
589 
590 	sc = gp->softc;
591 	KASSERT(sc, ("no softc"));
592 
593 	/*
594 	 * Make sure that the passed provider isn't already attached
595 	 */
596 	LIST_FOREACH(cp, &gp->consumer, consumer) {
597 		if (cp->provider == pp)
598 			break;
599 	}
600 	if (cp) {
601 		printf("GEOM_MULTIPATH: provider %s already attached to %s\n",
602 		    pp->name, gp->name);
603 		return (EEXIST);
604 	}
605 	cp = g_new_consumer(gp);
606 	cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
607 	cp->private = NULL;
608 	cp->index = MP_NEW;
609 	error = g_attach(cp, pp);
610 	if (error != 0) {
611 		printf("GEOM_MULTIPATH: cannot attach %s to %s",
612 		    pp->name, sc->sc_name);
613 		g_destroy_consumer(cp);
614 		return (error);
615 	}
616 
617 	/*
618 	 * Set access permissions on new consumer to match other consumers
619 	 */
620 	if (sc->sc_pp) {
621 		acr = sc->sc_pp->acr;
622 		acw = sc->sc_pp->acw;
623 		ace = sc->sc_pp->ace;
624 	} else
625 		acr = acw = ace = 0;
626 	if (g_multipath_exclusive) {
627 		acr++;
628 		acw++;
629 		ace++;
630 	}
631 	error = g_access(cp, acr, acw, ace);
632 	if (error) {
633 		printf("GEOM_MULTIPATH: cannot set access in "
634 		    "attaching %s to %s (%d)\n",
635 		    pp->name, sc->sc_name, error);
636 		g_detach(cp);
637 		g_destroy_consumer(cp);
638 		return (error);
639 	}
640 	if (sc->sc_size == 0) {
641 		sc->sc_size = pp->mediasize -
642 		    ((sc->sc_uuid[0] != 0) ? pp->sectorsize : 0);
643 		sc->sc_pp->mediasize = sc->sc_size;
644 		sc->sc_pp->sectorsize = pp->sectorsize;
645 	}
646 	if (sc->sc_pp->stripesize == 0 && sc->sc_pp->stripeoffset == 0) {
647 		sc->sc_pp->stripesize = pp->stripesize;
648 		sc->sc_pp->stripeoffset = pp->stripeoffset;
649 	}
650 	sc->sc_pp->flags |= pp->flags & G_PF_ACCEPT_UNMAPPED;
651 	mtx_lock(&sc->sc_mtx);
652 	cp->index = 0;
653 	sc->sc_ndisks++;
654 	mtx_unlock(&sc->sc_mtx);
655 	printf("GEOM_MULTIPATH: %s added to %s\n",
656 	    pp->name, sc->sc_name);
657 	if (sc->sc_active == NULL) {
658 		sc->sc_active = cp;
659 		if (sc->sc_active_active != 1)
660 			printf("GEOM_MULTIPATH: %s is now active path in %s\n",
661 			    pp->name, sc->sc_name);
662 	}
663 	return (0);
664 }
665 
666 static int
667 g_multipath_destroy(struct g_geom *gp)
668 {
669 	struct g_multipath_softc *sc;
670 	struct g_consumer *cp, *cp1;
671 
672 	g_topology_assert();
673 	if (gp->softc == NULL)
674 		return (ENXIO);
675 	sc = gp->softc;
676 	if (!sc->sc_stopping) {
677 		printf("GEOM_MULTIPATH: destroying %s\n", gp->name);
678 		sc->sc_stopping = 1;
679 	}
680 	if (sc->sc_opened != 0) {
681 		g_wither_provider(sc->sc_pp, ENXIO);
682 		sc->sc_pp = NULL;
683 		return (EINPROGRESS);
684 	}
685 	LIST_FOREACH_SAFE(cp, &gp->consumer, consumer, cp1) {
686 		mtx_lock(&sc->sc_mtx);
687 		if ((cp->index & MP_POSTED) == 0) {
688 			cp->index |= MP_POSTED;
689 			mtx_unlock(&sc->sc_mtx);
690 			g_mpd(cp, 0);
691 			if (cp1 == NULL)
692 				return(0);	/* Recursion happened. */
693 		} else
694 			mtx_unlock(&sc->sc_mtx);
695 	}
696 	if (!LIST_EMPTY(&gp->consumer))
697 		return (EINPROGRESS);
698 	mtx_destroy(&sc->sc_mtx);
699 	g_free(gp->softc);
700 	gp->softc = NULL;
701 	printf("GEOM_MULTIPATH: %s destroyed\n", gp->name);
702 	g_wither_geom(gp, ENXIO);
703 	return (0);
704 }
705 
706 static int
707 g_multipath_destroy_geom(struct gctl_req *req, struct g_class *mp,
708     struct g_geom *gp)
709 {
710 
711 	return (g_multipath_destroy(gp));
712 }
713 
714 static int
715 g_multipath_rotate(struct g_geom *gp)
716 {
717 	struct g_consumer *lcp, *first_good_cp = NULL;
718 	struct g_multipath_softc *sc = gp->softc;
719 	int active_cp_seen = 0;
720 
721 	g_topology_assert();
722 	if (sc == NULL)
723 		return (ENXIO);
724 	LIST_FOREACH(lcp, &gp->consumer, consumer) {
725 		if ((lcp->index & MP_BAD) == 0) {
726 			if (first_good_cp == NULL)
727 				first_good_cp = lcp;
728 			if (active_cp_seen)
729 				break;
730 		}
731 		if (sc->sc_active == lcp)
732 			active_cp_seen = 1;
733 	}
734 	if (lcp == NULL)
735 		lcp = first_good_cp;
736 	if (lcp && lcp != sc->sc_active) {
737 		sc->sc_active = lcp;
738 		if (sc->sc_active_active != 1)
739 			printf("GEOM_MULTIPATH: %s is now active path in %s\n",
740 			    lcp->provider->name, sc->sc_name);
741 	}
742 	return (0);
743 }
744 
745 static void
746 g_multipath_init(struct g_class *mp)
747 {
748 	bioq_init(&gmtbq);
749 	mtx_init(&gmtbq_mtx, "gmtbq", NULL, MTX_DEF);
750 	kproc_create(g_multipath_kt, mp, NULL, 0, 0, "g_mp_kt");
751 }
752 
753 static void
754 g_multipath_fini(struct g_class *mp)
755 {
756 	if (g_multipath_kt_state == GKT_RUN) {
757 		mtx_lock(&gmtbq_mtx);
758 		g_multipath_kt_state = GKT_DIE;
759 		wakeup(&g_multipath_kt_state);
760 		msleep(&g_multipath_kt_state, &gmtbq_mtx, PRIBIO,
761 		    "gmp:fini", 0);
762 		mtx_unlock(&gmtbq_mtx);
763 	}
764 }
765 
766 static int
767 g_multipath_read_metadata(struct g_consumer *cp,
768     struct g_multipath_metadata *md)
769 {
770 	struct g_provider *pp;
771 	u_char *buf;
772 	int error;
773 
774 	g_topology_assert();
775 	error = g_access(cp, 1, 0, 0);
776 	if (error != 0)
777 		return (error);
778 	pp = cp->provider;
779 	g_topology_unlock();
780 	buf = g_read_data(cp, pp->mediasize - pp->sectorsize,
781 	    pp->sectorsize, &error);
782 	g_topology_lock();
783 	g_access(cp, -1, 0, 0);
784 	if (buf == NULL)
785 		return (error);
786 	multipath_metadata_decode(buf, md);
787 	g_free(buf);
788 	return (0);
789 }
790 
791 static int
792 g_multipath_write_metadata(struct g_consumer *cp,
793     struct g_multipath_metadata *md)
794 {
795 	struct g_provider *pp;
796 	u_char *buf;
797 	int error;
798 
799 	g_topology_assert();
800 	error = g_access(cp, 1, 1, 1);
801 	if (error != 0)
802 		return (error);
803 	pp = cp->provider;
804 	g_topology_unlock();
805 	buf = g_malloc(pp->sectorsize, M_WAITOK | M_ZERO);
806 	multipath_metadata_encode(md, buf);
807 	error = g_write_data(cp, pp->mediasize - pp->sectorsize,
808 	    buf, pp->sectorsize);
809 	g_topology_lock();
810 	g_access(cp, -1, -1, -1);
811 	g_free(buf);
812 	return (error);
813 }
814 
815 static struct g_geom *
816 g_multipath_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
817 {
818 	struct g_multipath_metadata md;
819 	struct g_multipath_softc *sc;
820 	struct g_consumer *cp;
821 	struct g_geom *gp, *gp1;
822 	int error, isnew;
823 
824 	g_topology_assert();
825 
826 	gp = g_new_geomf(mp, "multipath:taste");
827 	gp->start = g_multipath_start;
828 	gp->access = g_multipath_access;
829 	gp->orphan = g_multipath_orphan;
830 	cp = g_new_consumer(gp);
831 	cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
832 	error = g_attach(cp, pp);
833 	if (error == 0) {
834 		error = g_multipath_read_metadata(cp, &md);
835 		g_detach(cp);
836 	}
837 	g_destroy_consumer(cp);
838 	g_destroy_geom(gp);
839 	if (error != 0)
840 		return (NULL);
841 	gp = NULL;
842 
843 	if (strcmp(md.md_magic, G_MULTIPATH_MAGIC) != 0) {
844 		if (g_multipath_debug)
845 			printf("%s is not MULTIPATH\n", pp->name);
846 		return (NULL);
847 	}
848 	if (md.md_version != G_MULTIPATH_VERSION) {
849 		printf("%s has version %d multipath id- this module is version "
850 		    " %d: rejecting\n", pp->name, md.md_version,
851 		    G_MULTIPATH_VERSION);
852 		return (NULL);
853 	}
854 	if (md.md_size != 0 && md.md_size != pp->mediasize)
855 		return (NULL);
856 	if (md.md_sectorsize != 0 && md.md_sectorsize != pp->sectorsize)
857 		return (NULL);
858 	if (g_multipath_debug)
859 		printf("MULTIPATH: %s/%s\n", md.md_name, md.md_uuid);
860 	SDT_PROBE2(geom, multipath, config, taste, md.md_name, md.md_uuid);
861 
862 	/*
863 	 * Let's check if such a device already is present. We check against
864 	 * uuid alone first because that's the true distinguishor. If that
865 	 * passes, then we check for name conflicts. If there are conflicts,
866 	 * modify the name.
867 	 *
868 	 * The whole purpose of this is to solve the problem that people don't
869 	 * pick good unique names, but good unique names (like uuids) are a
870 	 * pain to use. So, we allow people to build GEOMs with friendly names
871 	 * and uuids, and modify the names in case there's a collision.
872 	 */
873 	sc = NULL;
874 	LIST_FOREACH(gp, &mp->geom, geom) {
875 		sc = gp->softc;
876 		if (sc == NULL || sc->sc_stopping)
877 			continue;
878 		if (strncmp(md.md_uuid, sc->sc_uuid, sizeof(md.md_uuid)) == 0)
879 			break;
880 	}
881 
882 	LIST_FOREACH(gp1, &mp->geom, geom) {
883 		if (gp1 == gp)
884 			continue;
885 		sc = gp1->softc;
886 		if (sc == NULL || sc->sc_stopping)
887 			continue;
888 		if (strncmp(md.md_name, sc->sc_name, sizeof(md.md_name)) == 0)
889 			break;
890 	}
891 
892 	/*
893 	 * If gp is NULL, we had no extant MULTIPATH geom with this uuid.
894 	 *
895 	 * If gp1 is *not* NULL, that means we have a MULTIPATH geom extant
896 	 * with the same name (but a different UUID).
897 	 *
898 	 * If gp is NULL, then modify the name with a random number and
899   	 * complain, but allow the creation of the geom to continue.
900 	 *
901 	 * If gp is *not* NULL, just use the geom's name as we're attaching
902 	 * this disk to the (previously generated) name.
903 	 */
904 
905 	if (gp1) {
906 		sc = gp1->softc;
907 		if (gp == NULL) {
908 			char buf[16];
909 			u_long rand = random();
910 
911 			snprintf(buf, sizeof (buf), "%s-%lu", md.md_name, rand);
912 			printf("GEOM_MULTIPATH: geom %s/%s exists already\n",
913 			    sc->sc_name, sc->sc_uuid);
914 			printf("GEOM_MULTIPATH: %s will be (temporarily) %s\n",
915 			    md.md_uuid, buf);
916 			strlcpy(md.md_name, buf, sizeof(md.md_name));
917 		} else {
918 			strlcpy(md.md_name, sc->sc_name, sizeof(md.md_name));
919 		}
920 	}
921 
922 	if (gp == NULL) {
923 		gp = g_multipath_create(mp, &md);
924 		if (gp == NULL) {
925 			printf("GEOM_MULTIPATH: cannot create geom %s/%s\n",
926 			    md.md_name, md.md_uuid);
927 			return (NULL);
928 		}
929 		isnew = 1;
930 	} else {
931 		isnew = 0;
932 	}
933 
934 	sc = gp->softc;
935 	KASSERT(sc != NULL, ("sc is NULL"));
936 	error = g_multipath_add_disk(gp, pp);
937 	if (error != 0) {
938 		if (isnew)
939 			g_multipath_destroy(gp);
940 		return (NULL);
941 	}
942 	return (gp);
943 }
944 
945 static void
946 g_multipath_ctl_add_name(struct gctl_req *req, struct g_class *mp,
947     const char *name)
948 {
949 	struct g_multipath_softc *sc;
950 	struct g_geom *gp;
951 	struct g_consumer *cp;
952 	struct g_provider *pp;
953 	const char *mpname;
954 	static const char devpf[6] = _PATH_DEV;
955 	int error;
956 
957 	g_topology_assert();
958 
959 	mpname = gctl_get_asciiparam(req, "arg0");
960         if (mpname == NULL) {
961                 gctl_error(req, "No 'arg0' argument");
962                 return;
963         }
964 	gp = g_multipath_find_geom(mp, mpname);
965 	if (gp == NULL) {
966 		gctl_error(req, "Device %s is invalid", mpname);
967 		return;
968 	}
969 	sc = gp->softc;
970 
971 	if (strncmp(name, devpf, 5) == 0)
972 		name += 5;
973 	pp = g_provider_by_name(name);
974 	if (pp == NULL) {
975 		gctl_error(req, "Provider %s is invalid", name);
976 		return;
977 	}
978 
979 	/*
980 	 * Check to make sure parameters match.
981 	 */
982 	LIST_FOREACH(cp, &gp->consumer, consumer) {
983 		if (cp->provider == pp) {
984 			gctl_error(req, "provider %s is already there",
985 			    pp->name);
986 			return;
987 		}
988 	}
989 	if (sc->sc_pp->mediasize != 0 &&
990 	    sc->sc_pp->mediasize + (sc->sc_uuid[0] != 0 ? pp->sectorsize : 0)
991 	     != pp->mediasize) {
992 		gctl_error(req, "Providers size mismatch %jd != %jd",
993 		    (intmax_t) sc->sc_pp->mediasize +
994 			(sc->sc_uuid[0] != 0 ? pp->sectorsize : 0),
995 		    (intmax_t) pp->mediasize);
996 		return;
997 	}
998 	if (sc->sc_pp->sectorsize != 0 &&
999 	    sc->sc_pp->sectorsize != pp->sectorsize) {
1000 		gctl_error(req, "Providers sectorsize mismatch %u != %u",
1001 		    sc->sc_pp->sectorsize, pp->sectorsize);
1002 		return;
1003 	}
1004 
1005 	error = g_multipath_add_disk(gp, pp);
1006 	if (error != 0)
1007 		gctl_error(req, "Provider addition error: %d", error);
1008 }
1009 
1010 static void
1011 g_multipath_ctl_prefer(struct gctl_req *req, struct g_class *mp)
1012 {
1013 	struct g_geom *gp;
1014 	struct g_multipath_softc *sc;
1015 	struct g_consumer *cp;
1016 	const char *name, *mpname;
1017 	static const char devpf[6] = _PATH_DEV;
1018 	int *nargs;
1019 
1020 	g_topology_assert();
1021 
1022 	mpname = gctl_get_asciiparam(req, "arg0");
1023         if (mpname == NULL) {
1024                 gctl_error(req, "No 'arg0' argument");
1025                 return;
1026         }
1027 	gp = g_multipath_find_geom(mp, mpname);
1028 	if (gp == NULL) {
1029 		gctl_error(req, "Device %s is invalid", mpname);
1030 		return;
1031 	}
1032 	sc = gp->softc;
1033 
1034 	nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
1035 	if (nargs == NULL) {
1036 		gctl_error(req, "No 'nargs' argument");
1037 		return;
1038 	}
1039 	if (*nargs != 2) {
1040 		gctl_error(req, "missing device");
1041 		return;
1042 	}
1043 
1044 	name = gctl_get_asciiparam(req, "arg1");
1045 	if (name == NULL) {
1046 		gctl_error(req, "No 'arg1' argument");
1047 		return;
1048 	}
1049 	if (strncmp(name, devpf, 5) == 0) {
1050 		name += 5;
1051 	}
1052 
1053 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1054 		if (cp->provider != NULL
1055                       && strcmp(cp->provider->name, name) == 0)
1056 		    break;
1057 	}
1058 
1059 	if (cp == NULL) {
1060 		gctl_error(req, "Provider %s not found", name);
1061 		return;
1062 	}
1063 
1064 	mtx_lock(&sc->sc_mtx);
1065 
1066 	if (cp->index & MP_BAD) {
1067 		gctl_error(req, "Consumer %s is invalid", name);
1068 		mtx_unlock(&sc->sc_mtx);
1069 		return;
1070 	}
1071 
1072 	/* Here when the consumer is present and in good shape */
1073 
1074 	sc->sc_active = cp;
1075 	if (!sc->sc_active_active)
1076 	    printf("GEOM_MULTIPATH: %s now active path in %s\n",
1077 		sc->sc_active->provider->name, sc->sc_name);
1078 
1079 	mtx_unlock(&sc->sc_mtx);
1080 }
1081 
1082 static void
1083 g_multipath_ctl_add(struct gctl_req *req, struct g_class *mp)
1084 {
1085 	struct g_geom *gp;
1086 	const char *mpname, *name;
1087 
1088 	mpname = gctl_get_asciiparam(req, "arg0");
1089         if (mpname == NULL) {
1090                 gctl_error(req, "No 'arg0' argument");
1091                 return;
1092         }
1093 	gp = g_multipath_find_geom(mp, mpname);
1094 	if (gp == NULL) {
1095 		gctl_error(req, "Device %s not found", mpname);
1096 		return;
1097 	}
1098 
1099 	name = gctl_get_asciiparam(req, "arg1");
1100 	if (name == NULL) {
1101 		gctl_error(req, "No 'arg1' argument");
1102 		return;
1103 	}
1104 	g_multipath_ctl_add_name(req, mp, name);
1105 }
1106 
1107 static void
1108 g_multipath_ctl_create(struct gctl_req *req, struct g_class *mp)
1109 {
1110 	struct g_multipath_metadata md;
1111 	struct g_multipath_softc *sc;
1112 	struct g_geom *gp;
1113 	const char *mpname, *name;
1114 	char param[16];
1115 	int *nargs, i, *val;
1116 
1117 	g_topology_assert();
1118 
1119 	nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
1120 	if (*nargs < 2) {
1121 		gctl_error(req, "wrong number of arguments.");
1122 		return;
1123 	}
1124 
1125 	mpname = gctl_get_asciiparam(req, "arg0");
1126         if (mpname == NULL) {
1127                 gctl_error(req, "No 'arg0' argument");
1128                 return;
1129         }
1130 	gp = g_multipath_find_geom(mp, mpname);
1131 	if (gp != NULL) {
1132 		gctl_error(req, "Device %s already exist", mpname);
1133 		return;
1134 	}
1135 
1136 	memset(&md, 0, sizeof(md));
1137 	strlcpy(md.md_magic, G_MULTIPATH_MAGIC, sizeof(md.md_magic));
1138 	md.md_version = G_MULTIPATH_VERSION;
1139 	strlcpy(md.md_name, mpname, sizeof(md.md_name));
1140 	md.md_size = 0;
1141 	md.md_sectorsize = 0;
1142 	md.md_uuid[0] = 0;
1143 	md.md_active_active = 0;
1144 	val = gctl_get_paraml(req, "active_active", sizeof(*val));
1145 	if (val != NULL && *val != 0)
1146 		md.md_active_active = 1;
1147 	val = gctl_get_paraml(req, "active_read", sizeof(*val));
1148 	if (val != NULL && *val != 0)
1149 		md.md_active_active = 2;
1150 	gp = g_multipath_create(mp, &md);
1151 	if (gp == NULL) {
1152 		gctl_error(req, "GEOM_MULTIPATH: cannot create geom %s/%s\n",
1153 		    md.md_name, md.md_uuid);
1154 		return;
1155 	}
1156 	sc = gp->softc;
1157 
1158 	for (i = 1; i < *nargs; i++) {
1159 		snprintf(param, sizeof(param), "arg%d", i);
1160 		name = gctl_get_asciiparam(req, param);
1161 		g_multipath_ctl_add_name(req, mp, name);
1162 	}
1163 
1164 	if (sc->sc_ndisks != (*nargs - 1))
1165 		g_multipath_destroy(gp);
1166 }
1167 
1168 static void
1169 g_multipath_ctl_configure(struct gctl_req *req, struct g_class *mp)
1170 {
1171 	struct g_multipath_softc *sc;
1172 	struct g_geom *gp;
1173 	struct g_consumer *cp;
1174 	struct g_provider *pp;
1175 	struct g_multipath_metadata md;
1176 	const char *name;
1177 	int error, *val;
1178 
1179 	g_topology_assert();
1180 
1181 	name = gctl_get_asciiparam(req, "arg0");
1182 	if (name == NULL) {
1183 		gctl_error(req, "No 'arg0' argument");
1184 		return;
1185 	}
1186 	gp = g_multipath_find_geom(mp, name);
1187 	if (gp == NULL) {
1188 		gctl_error(req, "Device %s is invalid", name);
1189 		return;
1190 	}
1191 	sc = gp->softc;
1192 	val = gctl_get_paraml(req, "active_active", sizeof(*val));
1193 	if (val != NULL && *val != 0)
1194 		sc->sc_active_active = 1;
1195 	val = gctl_get_paraml(req, "active_read", sizeof(*val));
1196 	if (val != NULL && *val != 0)
1197 		sc->sc_active_active = 2;
1198 	val = gctl_get_paraml(req, "active_passive", sizeof(*val));
1199 	if (val != NULL && *val != 0)
1200 		sc->sc_active_active = 0;
1201 	if (sc->sc_uuid[0] != 0 && sc->sc_active != NULL) {
1202 		cp = sc->sc_active;
1203 		pp = cp->provider;
1204 		strlcpy(md.md_magic, G_MULTIPATH_MAGIC, sizeof(md.md_magic));
1205 		memcpy(md.md_uuid, sc->sc_uuid, sizeof (sc->sc_uuid));
1206 		strlcpy(md.md_name, name, sizeof(md.md_name));
1207 		md.md_version = G_MULTIPATH_VERSION;
1208 		md.md_size = pp->mediasize;
1209 		md.md_sectorsize = pp->sectorsize;
1210 		md.md_active_active = sc->sc_active_active;
1211 		error = g_multipath_write_metadata(cp, &md);
1212 		if (error != 0)
1213 			gctl_error(req, "Can't update metadata on %s (%d)",
1214 			    pp->name, error);
1215 	}
1216 }
1217 
1218 static void
1219 g_multipath_ctl_fail(struct gctl_req *req, struct g_class *mp, int fail)
1220 {
1221 	struct g_multipath_softc *sc;
1222 	struct g_geom *gp;
1223 	struct g_consumer *cp;
1224 	const char *mpname, *name;
1225 	int found;
1226 
1227 	mpname = gctl_get_asciiparam(req, "arg0");
1228         if (mpname == NULL) {
1229                 gctl_error(req, "No 'arg0' argument");
1230                 return;
1231         }
1232 	gp = g_multipath_find_geom(mp, mpname);
1233 	if (gp == NULL) {
1234 		gctl_error(req, "Device %s not found", mpname);
1235 		return;
1236 	}
1237 	sc = gp->softc;
1238 
1239 	name = gctl_get_asciiparam(req, "arg1");
1240 	if (name == NULL) {
1241 		gctl_error(req, "No 'arg1' argument");
1242 		return;
1243 	}
1244 
1245 	found = 0;
1246 	mtx_lock(&sc->sc_mtx);
1247 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1248 		if (cp->provider != NULL &&
1249 		    strcmp(cp->provider->name, name) == 0 &&
1250 		    (cp->index & MP_LOST) == 0) {
1251 			found = 1;
1252 			if (!fail == !(cp->index & MP_FAIL))
1253 				continue;
1254 			printf("GEOM_MULTIPATH: %s in %s is marked %s.\n",
1255 				name, sc->sc_name, fail ? "FAIL" : "OK");
1256 			if (fail) {
1257 				g_multipath_fault(cp, MP_FAIL);
1258 				SDT_PROBE3(geom, multipath, config, fail,
1259 				    sc->sc_name, cp->provider->name, 0);
1260 			} else {
1261 				cp->index &= ~MP_FAIL;
1262 				SDT_PROBE2(geom, multipath, config, restore,
1263 				    sc->sc_name, cp->provider->name);
1264 			}
1265 		}
1266 	}
1267 	mtx_unlock(&sc->sc_mtx);
1268 	if (found == 0)
1269 		gctl_error(req, "Provider %s not found", name);
1270 }
1271 
1272 static void
1273 g_multipath_ctl_remove(struct gctl_req *req, struct g_class *mp)
1274 {
1275 	struct g_multipath_softc *sc;
1276 	struct g_geom *gp;
1277 	struct g_consumer *cp, *cp1;
1278 	const char *mpname, *name;
1279 	uintptr_t *cnt;
1280 	int found;
1281 
1282 	mpname = gctl_get_asciiparam(req, "arg0");
1283         if (mpname == NULL) {
1284                 gctl_error(req, "No 'arg0' argument");
1285                 return;
1286         }
1287 	gp = g_multipath_find_geom(mp, mpname);
1288 	if (gp == NULL) {
1289 		gctl_error(req, "Device %s not found", mpname);
1290 		return;
1291 	}
1292 	sc = gp->softc;
1293 
1294 	name = gctl_get_asciiparam(req, "arg1");
1295 	if (name == NULL) {
1296 		gctl_error(req, "No 'arg1' argument");
1297 		return;
1298 	}
1299 
1300 	found = 0;
1301 	mtx_lock(&sc->sc_mtx);
1302 	LIST_FOREACH_SAFE(cp, &gp->consumer, consumer, cp1) {
1303 		if (cp->provider != NULL &&
1304 		    strcmp(cp->provider->name, name) == 0 &&
1305 		    (cp->index & MP_LOST) == 0) {
1306 			found = 1;
1307 			printf("GEOM_MULTIPATH: removing %s from %s\n",
1308 			    cp->provider->name, cp->geom->name);
1309 			SDT_PROBE2(geom, multipath, config, remove,
1310 			    cp->geom->name, cp->provider->name);
1311 			sc->sc_ndisks--;
1312 			g_multipath_fault(cp, MP_LOST);
1313 			cnt = (uintptr_t *)&cp->private;
1314 			if (*cnt == 0 && (cp->index & MP_POSTED) == 0) {
1315 				cp->index |= MP_POSTED;
1316 				mtx_unlock(&sc->sc_mtx);
1317 				g_mpd(cp, 0);
1318 				if (cp1 == NULL)
1319 					return;	/* Recursion happened. */
1320 				mtx_lock(&sc->sc_mtx);
1321 			}
1322 		}
1323 	}
1324 	mtx_unlock(&sc->sc_mtx);
1325 	if (found == 0)
1326 		gctl_error(req, "Provider %s not found", name);
1327 }
1328 
1329 static struct g_geom *
1330 g_multipath_find_geom(struct g_class *mp, const char *name)
1331 {
1332 	struct g_geom *gp;
1333 	struct g_multipath_softc *sc;
1334 
1335 	LIST_FOREACH(gp, &mp->geom, geom) {
1336 		sc = gp->softc;
1337 		if (sc == NULL || sc->sc_stopping)
1338 			continue;
1339 		if (strcmp(gp->name, name) == 0)
1340 			return (gp);
1341 	}
1342 	return (NULL);
1343 }
1344 
1345 static void
1346 g_multipath_ctl_stop(struct gctl_req *req, struct g_class *mp)
1347 {
1348 	struct g_geom *gp;
1349 	const char *name;
1350 	int error;
1351 
1352 	g_topology_assert();
1353 
1354 	name = gctl_get_asciiparam(req, "arg0");
1355         if (name == NULL) {
1356                 gctl_error(req, "No 'arg0' argument");
1357                 return;
1358         }
1359 	gp = g_multipath_find_geom(mp, name);
1360 	if (gp == NULL) {
1361 		gctl_error(req, "Device %s is invalid", name);
1362 		return;
1363 	}
1364 	error = g_multipath_destroy(gp);
1365 	if (error != 0 && error != EINPROGRESS)
1366 		gctl_error(req, "failed to stop %s (err=%d)", name, error);
1367 }
1368 
1369 static void
1370 g_multipath_ctl_destroy(struct gctl_req *req, struct g_class *mp)
1371 {
1372 	struct g_geom *gp;
1373 	struct g_multipath_softc *sc;
1374 	struct g_consumer *cp;
1375 	struct g_provider *pp;
1376 	const char *name;
1377 	uint8_t *buf;
1378 	int error;
1379 
1380 	g_topology_assert();
1381 
1382 	name = gctl_get_asciiparam(req, "arg0");
1383         if (name == NULL) {
1384                 gctl_error(req, "No 'arg0' argument");
1385                 return;
1386         }
1387 	gp = g_multipath_find_geom(mp, name);
1388 	if (gp == NULL) {
1389 		gctl_error(req, "Device %s is invalid", name);
1390 		return;
1391 	}
1392 	sc = gp->softc;
1393 
1394 	if (sc->sc_uuid[0] != 0 && sc->sc_active != NULL) {
1395 		cp = sc->sc_active;
1396 		pp = cp->provider;
1397 		error = g_access(cp, 1, 1, 1);
1398 		if (error != 0) {
1399 			gctl_error(req, "Can't open %s (%d)", pp->name, error);
1400 			goto destroy;
1401 		}
1402 		g_topology_unlock();
1403 		buf = g_malloc(pp->sectorsize, M_WAITOK | M_ZERO);
1404 		error = g_write_data(cp, pp->mediasize - pp->sectorsize,
1405 		    buf, pp->sectorsize);
1406 		g_topology_lock();
1407 		g_access(cp, -1, -1, -1);
1408 		if (error != 0)
1409 			gctl_error(req, "Can't erase metadata on %s (%d)",
1410 			    pp->name, error);
1411 	}
1412 
1413 destroy:
1414 	error = g_multipath_destroy(gp);
1415 	if (error != 0 && error != EINPROGRESS)
1416 		gctl_error(req, "failed to destroy %s (err=%d)", name, error);
1417 }
1418 
1419 static void
1420 g_multipath_ctl_rotate(struct gctl_req *req, struct g_class *mp)
1421 {
1422 	struct g_geom *gp;
1423 	const char *name;
1424 	int error;
1425 
1426 	g_topology_assert();
1427 
1428 	name = gctl_get_asciiparam(req, "arg0");
1429         if (name == NULL) {
1430                 gctl_error(req, "No 'arg0' argument");
1431                 return;
1432         }
1433 	gp = g_multipath_find_geom(mp, name);
1434 	if (gp == NULL) {
1435 		gctl_error(req, "Device %s is invalid", name);
1436 		return;
1437 	}
1438 	error = g_multipath_rotate(gp);
1439 	if (error != 0) {
1440 		gctl_error(req, "failed to rotate %s (err=%d)", name, error);
1441 	}
1442 }
1443 
1444 static void
1445 g_multipath_ctl_getactive(struct gctl_req *req, struct g_class *mp)
1446 {
1447 	struct sbuf *sb;
1448 	struct g_geom *gp;
1449 	struct g_multipath_softc *sc;
1450 	struct g_consumer *cp;
1451 	const char *name;
1452 	int empty;
1453 
1454 	sb = sbuf_new_auto();
1455 
1456 	g_topology_assert();
1457 	name = gctl_get_asciiparam(req, "arg0");
1458         if (name == NULL) {
1459                 gctl_error(req, "No 'arg0' argument");
1460                 return;
1461         }
1462 	gp = g_multipath_find_geom(mp, name);
1463 	if (gp == NULL) {
1464 		gctl_error(req, "Device %s is invalid", name);
1465 		return;
1466 	}
1467 	sc = gp->softc;
1468 	if (sc->sc_active_active == 1) {
1469 		empty = 1;
1470 		LIST_FOREACH(cp, &gp->consumer, consumer) {
1471 			if (cp->index & MP_BAD)
1472 				continue;
1473 			if (!empty)
1474 				sbuf_cat(sb, " ");
1475 			sbuf_cat(sb, cp->provider->name);
1476 			empty = 0;
1477 		}
1478 		if (empty)
1479 			sbuf_cat(sb, "none");
1480 		sbuf_cat(sb, "\n");
1481 	} else if (sc->sc_active && sc->sc_active->provider) {
1482 		sbuf_printf(sb, "%s\n", sc->sc_active->provider->name);
1483 	} else {
1484 		sbuf_cat(sb, "none\n");
1485 	}
1486 	sbuf_finish(sb);
1487 	gctl_set_param_err(req, "output", sbuf_data(sb), sbuf_len(sb) + 1);
1488 	sbuf_delete(sb);
1489 }
1490 
1491 static void
1492 g_multipath_config(struct gctl_req *req, struct g_class *mp, const char *verb)
1493 {
1494 	uint32_t *version;
1495 	g_topology_assert();
1496 	version = gctl_get_paraml(req, "version", sizeof(*version));
1497 	if (version == NULL) {
1498 		gctl_error(req, "No 'version' argument");
1499 	} else if (*version != G_MULTIPATH_VERSION) {
1500 		gctl_error(req, "Userland and kernel parts are out of sync");
1501 	} else if (strcmp(verb, "add") == 0) {
1502 		g_multipath_ctl_add(req, mp);
1503 	} else if (strcmp(verb, "prefer") == 0) {
1504 		g_multipath_ctl_prefer(req, mp);
1505 	} else if (strcmp(verb, "create") == 0) {
1506 		g_multipath_ctl_create(req, mp);
1507 	} else if (strcmp(verb, "configure") == 0) {
1508 		g_multipath_ctl_configure(req, mp);
1509 	} else if (strcmp(verb, "stop") == 0) {
1510 		g_multipath_ctl_stop(req, mp);
1511 	} else if (strcmp(verb, "destroy") == 0) {
1512 		g_multipath_ctl_destroy(req, mp);
1513 	} else if (strcmp(verb, "fail") == 0) {
1514 		g_multipath_ctl_fail(req, mp, 1);
1515 	} else if (strcmp(verb, "restore") == 0) {
1516 		g_multipath_ctl_fail(req, mp, 0);
1517 	} else if (strcmp(verb, "remove") == 0) {
1518 		g_multipath_ctl_remove(req, mp);
1519 	} else if (strcmp(verb, "rotate") == 0) {
1520 		g_multipath_ctl_rotate(req, mp);
1521 	} else if (strcmp(verb, "getactive") == 0) {
1522 		g_multipath_ctl_getactive(req, mp);
1523 	} else {
1524 		gctl_error(req, "Unknown verb %s", verb);
1525 	}
1526 }
1527 
1528 static void
1529 g_multipath_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1530     struct g_consumer *cp, struct g_provider *pp)
1531 {
1532 	struct g_multipath_softc *sc;
1533 	int good;
1534 
1535 	g_topology_assert();
1536 
1537 	sc = gp->softc;
1538 	if (sc == NULL)
1539 		return;
1540 	if (cp != NULL) {
1541 		sbuf_printf(sb, "%s<State>%s</State>\n", indent,
1542 		    (cp->index & MP_NEW) ? "NEW" :
1543 		    (cp->index & MP_LOST) ? "LOST" :
1544 		    (cp->index & MP_FAIL) ? "FAIL" :
1545 		    (sc->sc_active_active == 1 || sc->sc_active == cp) ?
1546 		     "ACTIVE" :
1547 		     sc->sc_active_active == 2 ? "READ" : "PASSIVE");
1548 	} else {
1549 		good = g_multipath_good(gp);
1550 		sbuf_printf(sb, "%s<State>%s</State>\n", indent,
1551 		    good == 0 ? "BROKEN" :
1552 		    (good != sc->sc_ndisks || sc->sc_ndisks == 1) ?
1553 		    "DEGRADED" : "OPTIMAL");
1554 	}
1555 	if (cp == NULL && pp == NULL) {
1556 		sbuf_printf(sb, "%s<UUID>%s</UUID>\n", indent, sc->sc_uuid);
1557 		sbuf_printf(sb, "%s<Mode>Active/%s</Mode>\n", indent,
1558 		    sc->sc_active_active == 2 ? "Read" :
1559 		    sc->sc_active_active == 1 ? "Active" : "Passive");
1560 		sbuf_printf(sb, "%s<Type>%s</Type>\n", indent,
1561 		    sc->sc_uuid[0] == 0 ? "MANUAL" : "AUTOMATIC");
1562 	}
1563 }
1564 
1565 DECLARE_GEOM_CLASS(g_multipath_class, g_multipath);
1566 MODULE_VERSION(geom_multipath, 0);
1567