xref: /freebsd/sys/geom/mirror/g_mirror.c (revision cbd30a72ca196976c1c700400ecd424baa1b9c16)
1 /*-
2  * Copyright (c) 2004-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/fail.h>
33 #include <sys/kernel.h>
34 #include <sys/module.h>
35 #include <sys/limits.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/bio.h>
39 #include <sys/sbuf.h>
40 #include <sys/sysctl.h>
41 #include <sys/malloc.h>
42 #include <sys/eventhandler.h>
43 #include <vm/uma.h>
44 #include <geom/geom.h>
45 #include <sys/proc.h>
46 #include <sys/kthread.h>
47 #include <sys/sched.h>
48 #include <geom/mirror/g_mirror.h>
49 
50 FEATURE(geom_mirror, "GEOM mirroring support");
51 
52 static MALLOC_DEFINE(M_MIRROR, "mirror_data", "GEOM_MIRROR Data");
53 
54 SYSCTL_DECL(_kern_geom);
55 static SYSCTL_NODE(_kern_geom, OID_AUTO, mirror, CTLFLAG_RW, 0,
56     "GEOM_MIRROR stuff");
57 u_int g_mirror_debug = 0;
58 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, debug, CTLFLAG_RWTUN, &g_mirror_debug, 0,
59     "Debug level");
60 static u_int g_mirror_timeout = 4;
61 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, timeout, CTLFLAG_RWTUN, &g_mirror_timeout,
62     0, "Time to wait on all mirror components");
63 static u_int g_mirror_idletime = 5;
64 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, idletime, CTLFLAG_RWTUN,
65     &g_mirror_idletime, 0, "Mark components as clean when idling");
66 static u_int g_mirror_disconnect_on_failure = 1;
67 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, disconnect_on_failure, CTLFLAG_RWTUN,
68     &g_mirror_disconnect_on_failure, 0, "Disconnect component on I/O failure.");
69 static u_int g_mirror_syncreqs = 2;
70 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, sync_requests, CTLFLAG_RDTUN,
71     &g_mirror_syncreqs, 0, "Parallel synchronization I/O requests.");
72 
73 #define	MSLEEP(ident, mtx, priority, wmesg, timeout)	do {		\
74 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, (ident));	\
75 	msleep((ident), (mtx), (priority), (wmesg), (timeout));		\
76 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, (ident));	\
77 } while (0)
78 
79 static eventhandler_tag g_mirror_post_sync = NULL;
80 static int g_mirror_shutdown = 0;
81 
82 static g_ctl_destroy_geom_t g_mirror_destroy_geom;
83 static g_taste_t g_mirror_taste;
84 static g_init_t g_mirror_init;
85 static g_fini_t g_mirror_fini;
86 static g_provgone_t g_mirror_providergone;
87 static g_resize_t g_mirror_resize;
88 
89 struct g_class g_mirror_class = {
90 	.name = G_MIRROR_CLASS_NAME,
91 	.version = G_VERSION,
92 	.ctlreq = g_mirror_config,
93 	.taste = g_mirror_taste,
94 	.destroy_geom = g_mirror_destroy_geom,
95 	.init = g_mirror_init,
96 	.fini = g_mirror_fini,
97 	.providergone = g_mirror_providergone,
98 	.resize = g_mirror_resize
99 };
100 
101 
102 static void g_mirror_destroy_provider(struct g_mirror_softc *sc);
103 static int g_mirror_update_disk(struct g_mirror_disk *disk, u_int state);
104 static void g_mirror_update_device(struct g_mirror_softc *sc, bool force);
105 static void g_mirror_dumpconf(struct sbuf *sb, const char *indent,
106     struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp);
107 static void g_mirror_sync_stop(struct g_mirror_disk *disk, int type);
108 static void g_mirror_register_request(struct bio *bp);
109 static void g_mirror_sync_release(struct g_mirror_softc *sc);
110 
111 
112 static const char *
113 g_mirror_disk_state2str(int state)
114 {
115 
116 	switch (state) {
117 	case G_MIRROR_DISK_STATE_NONE:
118 		return ("NONE");
119 	case G_MIRROR_DISK_STATE_NEW:
120 		return ("NEW");
121 	case G_MIRROR_DISK_STATE_ACTIVE:
122 		return ("ACTIVE");
123 	case G_MIRROR_DISK_STATE_STALE:
124 		return ("STALE");
125 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
126 		return ("SYNCHRONIZING");
127 	case G_MIRROR_DISK_STATE_DISCONNECTED:
128 		return ("DISCONNECTED");
129 	case G_MIRROR_DISK_STATE_DESTROY:
130 		return ("DESTROY");
131 	default:
132 		return ("INVALID");
133 	}
134 }
135 
136 static const char *
137 g_mirror_device_state2str(int state)
138 {
139 
140 	switch (state) {
141 	case G_MIRROR_DEVICE_STATE_STARTING:
142 		return ("STARTING");
143 	case G_MIRROR_DEVICE_STATE_RUNNING:
144 		return ("RUNNING");
145 	default:
146 		return ("INVALID");
147 	}
148 }
149 
150 static const char *
151 g_mirror_get_diskname(struct g_mirror_disk *disk)
152 {
153 
154 	if (disk->d_consumer == NULL || disk->d_consumer->provider == NULL)
155 		return ("[unknown]");
156 	return (disk->d_name);
157 }
158 
159 /*
160  * --- Events handling functions ---
161  * Events in geom_mirror are used to maintain disks and device status
162  * from one thread to simplify locking.
163  */
164 static void
165 g_mirror_event_free(struct g_mirror_event *ep)
166 {
167 
168 	free(ep, M_MIRROR);
169 }
170 
171 int
172 g_mirror_event_send(void *arg, int state, int flags)
173 {
174 	struct g_mirror_softc *sc;
175 	struct g_mirror_disk *disk;
176 	struct g_mirror_event *ep;
177 	int error;
178 
179 	ep = malloc(sizeof(*ep), M_MIRROR, M_WAITOK);
180 	G_MIRROR_DEBUG(4, "%s: Sending event %p.", __func__, ep);
181 	if ((flags & G_MIRROR_EVENT_DEVICE) != 0) {
182 		disk = NULL;
183 		sc = arg;
184 	} else {
185 		disk = arg;
186 		sc = disk->d_softc;
187 	}
188 	ep->e_disk = disk;
189 	ep->e_state = state;
190 	ep->e_flags = flags;
191 	ep->e_error = 0;
192 	mtx_lock(&sc->sc_events_mtx);
193 	TAILQ_INSERT_TAIL(&sc->sc_events, ep, e_next);
194 	mtx_unlock(&sc->sc_events_mtx);
195 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
196 	mtx_lock(&sc->sc_queue_mtx);
197 	wakeup(sc);
198 	mtx_unlock(&sc->sc_queue_mtx);
199 	if ((flags & G_MIRROR_EVENT_DONTWAIT) != 0)
200 		return (0);
201 	sx_assert(&sc->sc_lock, SX_XLOCKED);
202 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, ep);
203 	sx_xunlock(&sc->sc_lock);
204 	while ((ep->e_flags & G_MIRROR_EVENT_DONE) == 0) {
205 		mtx_lock(&sc->sc_events_mtx);
206 		MSLEEP(ep, &sc->sc_events_mtx, PRIBIO | PDROP, "m:event",
207 		    hz * 5);
208 	}
209 	error = ep->e_error;
210 	g_mirror_event_free(ep);
211 	sx_xlock(&sc->sc_lock);
212 	return (error);
213 }
214 
215 static struct g_mirror_event *
216 g_mirror_event_get(struct g_mirror_softc *sc)
217 {
218 	struct g_mirror_event *ep;
219 
220 	mtx_lock(&sc->sc_events_mtx);
221 	ep = TAILQ_FIRST(&sc->sc_events);
222 	mtx_unlock(&sc->sc_events_mtx);
223 	return (ep);
224 }
225 
226 static void
227 g_mirror_event_remove(struct g_mirror_softc *sc, struct g_mirror_event *ep)
228 {
229 
230 	mtx_lock(&sc->sc_events_mtx);
231 	TAILQ_REMOVE(&sc->sc_events, ep, e_next);
232 	mtx_unlock(&sc->sc_events_mtx);
233 }
234 
235 static void
236 g_mirror_event_cancel(struct g_mirror_disk *disk)
237 {
238 	struct g_mirror_softc *sc;
239 	struct g_mirror_event *ep, *tmpep;
240 
241 	sc = disk->d_softc;
242 	sx_assert(&sc->sc_lock, SX_XLOCKED);
243 
244 	mtx_lock(&sc->sc_events_mtx);
245 	TAILQ_FOREACH_SAFE(ep, &sc->sc_events, e_next, tmpep) {
246 		if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0)
247 			continue;
248 		if (ep->e_disk != disk)
249 			continue;
250 		TAILQ_REMOVE(&sc->sc_events, ep, e_next);
251 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
252 			g_mirror_event_free(ep);
253 		else {
254 			ep->e_error = ECANCELED;
255 			wakeup(ep);
256 		}
257 	}
258 	mtx_unlock(&sc->sc_events_mtx);
259 }
260 
261 /*
262  * Return the number of disks in given state.
263  * If state is equal to -1, count all connected disks.
264  */
265 u_int
266 g_mirror_ndisks(struct g_mirror_softc *sc, int state)
267 {
268 	struct g_mirror_disk *disk;
269 	u_int n = 0;
270 
271 	sx_assert(&sc->sc_lock, SX_LOCKED);
272 
273 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
274 		if (state == -1 || disk->d_state == state)
275 			n++;
276 	}
277 	return (n);
278 }
279 
280 /*
281  * Find a disk in mirror by its disk ID.
282  */
283 static struct g_mirror_disk *
284 g_mirror_id2disk(struct g_mirror_softc *sc, uint32_t id)
285 {
286 	struct g_mirror_disk *disk;
287 
288 	sx_assert(&sc->sc_lock, SX_XLOCKED);
289 
290 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
291 		if (disk->d_id == id)
292 			return (disk);
293 	}
294 	return (NULL);
295 }
296 
297 static u_int
298 g_mirror_nrequests(struct g_mirror_softc *sc, struct g_consumer *cp)
299 {
300 	struct bio *bp;
301 	u_int nreqs = 0;
302 
303 	mtx_lock(&sc->sc_queue_mtx);
304 	TAILQ_FOREACH(bp, &sc->sc_queue.queue, bio_queue) {
305 		if (bp->bio_from == cp)
306 			nreqs++;
307 	}
308 	mtx_unlock(&sc->sc_queue_mtx);
309 	return (nreqs);
310 }
311 
312 static int
313 g_mirror_is_busy(struct g_mirror_softc *sc, struct g_consumer *cp)
314 {
315 
316 	if (cp->index > 0) {
317 		G_MIRROR_DEBUG(2,
318 		    "I/O requests for %s exist, can't destroy it now.",
319 		    cp->provider->name);
320 		return (1);
321 	}
322 	if (g_mirror_nrequests(sc, cp) > 0) {
323 		G_MIRROR_DEBUG(2,
324 		    "I/O requests for %s in queue, can't destroy it now.",
325 		    cp->provider->name);
326 		return (1);
327 	}
328 	return (0);
329 }
330 
331 static void
332 g_mirror_destroy_consumer(void *arg, int flags __unused)
333 {
334 	struct g_consumer *cp;
335 
336 	g_topology_assert();
337 
338 	cp = arg;
339 	G_MIRROR_DEBUG(1, "Consumer %s destroyed.", cp->provider->name);
340 	g_detach(cp);
341 	g_destroy_consumer(cp);
342 }
343 
344 static void
345 g_mirror_kill_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
346 {
347 	struct g_provider *pp;
348 	int retaste_wait;
349 
350 	g_topology_assert();
351 
352 	cp->private = NULL;
353 	if (g_mirror_is_busy(sc, cp))
354 		return;
355 	pp = cp->provider;
356 	retaste_wait = 0;
357 	if (cp->acw == 1) {
358 		if ((pp->geom->flags & G_GEOM_WITHER) == 0)
359 			retaste_wait = 1;
360 	}
361 	G_MIRROR_DEBUG(2, "Access %s r%dw%de%d = %d", pp->name, -cp->acr,
362 	    -cp->acw, -cp->ace, 0);
363 	if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
364 		g_access(cp, -cp->acr, -cp->acw, -cp->ace);
365 	if (retaste_wait) {
366 		/*
367 		 * After retaste event was send (inside g_access()), we can send
368 		 * event to detach and destroy consumer.
369 		 * A class, which has consumer to the given provider connected
370 		 * will not receive retaste event for the provider.
371 		 * This is the way how I ignore retaste events when I close
372 		 * consumers opened for write: I detach and destroy consumer
373 		 * after retaste event is sent.
374 		 */
375 		g_post_event(g_mirror_destroy_consumer, cp, M_WAITOK, NULL);
376 		return;
377 	}
378 	G_MIRROR_DEBUG(1, "Consumer %s destroyed.", pp->name);
379 	g_detach(cp);
380 	g_destroy_consumer(cp);
381 }
382 
383 static int
384 g_mirror_connect_disk(struct g_mirror_disk *disk, struct g_provider *pp)
385 {
386 	struct g_consumer *cp;
387 	int error;
388 
389 	g_topology_assert_not();
390 	KASSERT(disk->d_consumer == NULL,
391 	    ("Disk already connected (device %s).", disk->d_softc->sc_name));
392 
393 	g_topology_lock();
394 	cp = g_new_consumer(disk->d_softc->sc_geom);
395 	cp->flags |= G_CF_DIRECT_RECEIVE;
396 	error = g_attach(cp, pp);
397 	if (error != 0) {
398 		g_destroy_consumer(cp);
399 		g_topology_unlock();
400 		return (error);
401 	}
402 	error = g_access(cp, 1, 1, 1);
403 	if (error != 0) {
404 		g_detach(cp);
405 		g_destroy_consumer(cp);
406 		g_topology_unlock();
407 		G_MIRROR_DEBUG(0, "Cannot open consumer %s (error=%d).",
408 		    pp->name, error);
409 		return (error);
410 	}
411 	g_topology_unlock();
412 	disk->d_consumer = cp;
413 	disk->d_consumer->private = disk;
414 	disk->d_consumer->index = 0;
415 
416 	G_MIRROR_DEBUG(2, "Disk %s connected.", g_mirror_get_diskname(disk));
417 	return (0);
418 }
419 
420 static void
421 g_mirror_disconnect_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
422 {
423 
424 	g_topology_assert();
425 
426 	if (cp == NULL)
427 		return;
428 	if (cp->provider != NULL)
429 		g_mirror_kill_consumer(sc, cp);
430 	else
431 		g_destroy_consumer(cp);
432 }
433 
434 /*
435  * Initialize disk. This means allocate memory, create consumer, attach it
436  * to the provider and open access (r1w1e1) to it.
437  */
438 static struct g_mirror_disk *
439 g_mirror_init_disk(struct g_mirror_softc *sc, struct g_provider *pp,
440     struct g_mirror_metadata *md, int *errorp)
441 {
442 	struct g_mirror_disk *disk;
443 	int i, error;
444 
445 	disk = malloc(sizeof(*disk), M_MIRROR, M_NOWAIT | M_ZERO);
446 	if (disk == NULL) {
447 		error = ENOMEM;
448 		goto fail;
449 	}
450 	disk->d_softc = sc;
451 	error = g_mirror_connect_disk(disk, pp);
452 	if (error != 0)
453 		goto fail;
454 	disk->d_id = md->md_did;
455 	disk->d_state = G_MIRROR_DISK_STATE_NONE;
456 	disk->d_priority = md->md_priority;
457 	disk->d_flags = md->md_dflags;
458 	error = g_getattr("GEOM::candelete", disk->d_consumer, &i);
459 	if (error == 0 && i != 0)
460 		disk->d_flags |= G_MIRROR_DISK_FLAG_CANDELETE;
461 	if (md->md_provider[0] != '\0')
462 		disk->d_flags |= G_MIRROR_DISK_FLAG_HARDCODED;
463 	disk->d_sync.ds_consumer = NULL;
464 	disk->d_sync.ds_offset = md->md_sync_offset;
465 	disk->d_sync.ds_offset_done = md->md_sync_offset;
466 	disk->d_genid = md->md_genid;
467 	disk->d_sync.ds_syncid = md->md_syncid;
468 	if (errorp != NULL)
469 		*errorp = 0;
470 	return (disk);
471 fail:
472 	if (errorp != NULL)
473 		*errorp = error;
474 	if (disk != NULL)
475 		free(disk, M_MIRROR);
476 	return (NULL);
477 }
478 
479 static void
480 g_mirror_destroy_disk(struct g_mirror_disk *disk)
481 {
482 	struct g_mirror_softc *sc;
483 
484 	g_topology_assert_not();
485 	sc = disk->d_softc;
486 	sx_assert(&sc->sc_lock, SX_XLOCKED);
487 
488 	LIST_REMOVE(disk, d_next);
489 	g_mirror_event_cancel(disk);
490 	if (sc->sc_hint == disk)
491 		sc->sc_hint = NULL;
492 	switch (disk->d_state) {
493 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
494 		g_mirror_sync_stop(disk, 1);
495 		/* FALLTHROUGH */
496 	case G_MIRROR_DISK_STATE_NEW:
497 	case G_MIRROR_DISK_STATE_STALE:
498 	case G_MIRROR_DISK_STATE_ACTIVE:
499 		g_topology_lock();
500 		g_mirror_disconnect_consumer(sc, disk->d_consumer);
501 		g_topology_unlock();
502 		free(disk, M_MIRROR);
503 		break;
504 	default:
505 		KASSERT(0 == 1, ("Wrong disk state (%s, %s).",
506 		    g_mirror_get_diskname(disk),
507 		    g_mirror_disk_state2str(disk->d_state)));
508 	}
509 }
510 
511 static void
512 g_mirror_free_device(struct g_mirror_softc *sc)
513 {
514 
515 	mtx_destroy(&sc->sc_queue_mtx);
516 	mtx_destroy(&sc->sc_events_mtx);
517 	mtx_destroy(&sc->sc_done_mtx);
518 	sx_destroy(&sc->sc_lock);
519 	free(sc, M_MIRROR);
520 }
521 
522 static void
523 g_mirror_providergone(struct g_provider *pp)
524 {
525 	struct g_mirror_softc *sc = pp->private;
526 
527 	if ((--sc->sc_refcnt) == 0)
528 		g_mirror_free_device(sc);
529 }
530 
531 static void
532 g_mirror_destroy_device(struct g_mirror_softc *sc)
533 {
534 	struct g_mirror_disk *disk;
535 	struct g_mirror_event *ep;
536 	struct g_geom *gp;
537 	struct g_consumer *cp, *tmpcp;
538 
539 	g_topology_assert_not();
540 	sx_assert(&sc->sc_lock, SX_XLOCKED);
541 
542 	gp = sc->sc_geom;
543 	if (sc->sc_provider != NULL)
544 		g_mirror_destroy_provider(sc);
545 	for (disk = LIST_FIRST(&sc->sc_disks); disk != NULL;
546 	    disk = LIST_FIRST(&sc->sc_disks)) {
547 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
548 		g_mirror_update_metadata(disk);
549 		g_mirror_destroy_disk(disk);
550 	}
551 	while ((ep = g_mirror_event_get(sc)) != NULL) {
552 		g_mirror_event_remove(sc, ep);
553 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
554 			g_mirror_event_free(ep);
555 		else {
556 			ep->e_error = ECANCELED;
557 			ep->e_flags |= G_MIRROR_EVENT_DONE;
558 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, ep);
559 			mtx_lock(&sc->sc_events_mtx);
560 			wakeup(ep);
561 			mtx_unlock(&sc->sc_events_mtx);
562 		}
563 	}
564 	callout_drain(&sc->sc_callout);
565 
566 	g_topology_lock();
567 	LIST_FOREACH_SAFE(cp, &sc->sc_sync.ds_geom->consumer, consumer, tmpcp) {
568 		g_mirror_disconnect_consumer(sc, cp);
569 	}
570 	g_wither_geom(sc->sc_sync.ds_geom, ENXIO);
571 	G_MIRROR_DEBUG(0, "Device %s destroyed.", gp->name);
572 	g_wither_geom(gp, ENXIO);
573 	sx_xunlock(&sc->sc_lock);
574 	if ((--sc->sc_refcnt) == 0)
575 		g_mirror_free_device(sc);
576 	g_topology_unlock();
577 }
578 
579 static void
580 g_mirror_orphan(struct g_consumer *cp)
581 {
582 	struct g_mirror_disk *disk;
583 
584 	g_topology_assert();
585 
586 	disk = cp->private;
587 	if (disk == NULL)
588 		return;
589 	disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
590 	g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
591 	    G_MIRROR_EVENT_DONTWAIT);
592 }
593 
594 /*
595  * Function should return the next active disk on the list.
596  * It is possible that it will be the same disk as given.
597  * If there are no active disks on list, NULL is returned.
598  */
599 static __inline struct g_mirror_disk *
600 g_mirror_find_next(struct g_mirror_softc *sc, struct g_mirror_disk *disk)
601 {
602 	struct g_mirror_disk *dp;
603 
604 	for (dp = LIST_NEXT(disk, d_next); dp != disk;
605 	    dp = LIST_NEXT(dp, d_next)) {
606 		if (dp == NULL)
607 			dp = LIST_FIRST(&sc->sc_disks);
608 		if (dp->d_state == G_MIRROR_DISK_STATE_ACTIVE)
609 			break;
610 	}
611 	if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
612 		return (NULL);
613 	return (dp);
614 }
615 
616 static struct g_mirror_disk *
617 g_mirror_get_disk(struct g_mirror_softc *sc)
618 {
619 	struct g_mirror_disk *disk;
620 
621 	if (sc->sc_hint == NULL) {
622 		sc->sc_hint = LIST_FIRST(&sc->sc_disks);
623 		if (sc->sc_hint == NULL)
624 			return (NULL);
625 	}
626 	disk = sc->sc_hint;
627 	if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE) {
628 		disk = g_mirror_find_next(sc, disk);
629 		if (disk == NULL)
630 			return (NULL);
631 	}
632 	sc->sc_hint = g_mirror_find_next(sc, disk);
633 	return (disk);
634 }
635 
636 static int
637 g_mirror_write_metadata(struct g_mirror_disk *disk,
638     struct g_mirror_metadata *md)
639 {
640 	struct g_mirror_softc *sc;
641 	struct g_consumer *cp;
642 	off_t offset, length;
643 	u_char *sector;
644 	int error = 0;
645 
646 	g_topology_assert_not();
647 	sc = disk->d_softc;
648 	sx_assert(&sc->sc_lock, SX_LOCKED);
649 
650 	cp = disk->d_consumer;
651 	KASSERT(cp != NULL, ("NULL consumer (%s).", sc->sc_name));
652 	KASSERT(cp->provider != NULL, ("NULL provider (%s).", sc->sc_name));
653 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
654 	    ("Consumer %s closed? (r%dw%de%d).", cp->provider->name, cp->acr,
655 	    cp->acw, cp->ace));
656 	length = cp->provider->sectorsize;
657 	offset = cp->provider->mediasize - length;
658 	sector = malloc((size_t)length, M_MIRROR, M_WAITOK | M_ZERO);
659 	if (md != NULL &&
660 	    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_WIPE) == 0) {
661 		/*
662 		 * Handle the case, when the size of parent provider reduced.
663 		 */
664 		if (offset < md->md_mediasize)
665 			error = ENOSPC;
666 		else
667 			mirror_metadata_encode(md, sector);
668 	}
669 	KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_metadata_write, error);
670 	if (error == 0)
671 		error = g_write_data(cp, offset, sector, length);
672 	free(sector, M_MIRROR);
673 	if (error != 0) {
674 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_BROKEN) == 0) {
675 			disk->d_flags |= G_MIRROR_DISK_FLAG_BROKEN;
676 			G_MIRROR_DEBUG(0, "Cannot write metadata on %s "
677 			    "(device=%s, error=%d).",
678 			    g_mirror_get_diskname(disk), sc->sc_name, error);
679 		} else {
680 			G_MIRROR_DEBUG(1, "Cannot write metadata on %s "
681 			    "(device=%s, error=%d).",
682 			    g_mirror_get_diskname(disk), sc->sc_name, error);
683 		}
684 		if (g_mirror_disconnect_on_failure &&
685 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 1) {
686 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
687 			g_mirror_event_send(disk,
688 			    G_MIRROR_DISK_STATE_DISCONNECTED,
689 			    G_MIRROR_EVENT_DONTWAIT);
690 		}
691 	}
692 	return (error);
693 }
694 
695 static int
696 g_mirror_clear_metadata(struct g_mirror_disk *disk)
697 {
698 	int error;
699 
700 	g_topology_assert_not();
701 	sx_assert(&disk->d_softc->sc_lock, SX_LOCKED);
702 
703 	if (disk->d_softc->sc_type != G_MIRROR_TYPE_AUTOMATIC)
704 		return (0);
705 	error = g_mirror_write_metadata(disk, NULL);
706 	if (error == 0) {
707 		G_MIRROR_DEBUG(2, "Metadata on %s cleared.",
708 		    g_mirror_get_diskname(disk));
709 	} else {
710 		G_MIRROR_DEBUG(0,
711 		    "Cannot clear metadata on disk %s (error=%d).",
712 		    g_mirror_get_diskname(disk), error);
713 	}
714 	return (error);
715 }
716 
717 void
718 g_mirror_fill_metadata(struct g_mirror_softc *sc, struct g_mirror_disk *disk,
719     struct g_mirror_metadata *md)
720 {
721 
722 	strlcpy(md->md_magic, G_MIRROR_MAGIC, sizeof(md->md_magic));
723 	md->md_version = G_MIRROR_VERSION;
724 	strlcpy(md->md_name, sc->sc_name, sizeof(md->md_name));
725 	md->md_mid = sc->sc_id;
726 	md->md_all = sc->sc_ndisks;
727 	md->md_slice = sc->sc_slice;
728 	md->md_balance = sc->sc_balance;
729 	md->md_genid = sc->sc_genid;
730 	md->md_mediasize = sc->sc_mediasize;
731 	md->md_sectorsize = sc->sc_sectorsize;
732 	md->md_mflags = (sc->sc_flags & G_MIRROR_DEVICE_FLAG_MASK);
733 	bzero(md->md_provider, sizeof(md->md_provider));
734 	if (disk == NULL) {
735 		md->md_did = arc4random();
736 		md->md_priority = 0;
737 		md->md_syncid = 0;
738 		md->md_dflags = 0;
739 		md->md_sync_offset = 0;
740 		md->md_provsize = 0;
741 	} else {
742 		md->md_did = disk->d_id;
743 		md->md_priority = disk->d_priority;
744 		md->md_syncid = disk->d_sync.ds_syncid;
745 		md->md_dflags = (disk->d_flags & G_MIRROR_DISK_FLAG_MASK);
746 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
747 			md->md_sync_offset = disk->d_sync.ds_offset_done;
748 		else
749 			md->md_sync_offset = 0;
750 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_HARDCODED) != 0) {
751 			strlcpy(md->md_provider,
752 			    disk->d_consumer->provider->name,
753 			    sizeof(md->md_provider));
754 		}
755 		md->md_provsize = disk->d_consumer->provider->mediasize;
756 	}
757 }
758 
759 void
760 g_mirror_update_metadata(struct g_mirror_disk *disk)
761 {
762 	struct g_mirror_softc *sc;
763 	struct g_mirror_metadata md;
764 	int error;
765 
766 	g_topology_assert_not();
767 	sc = disk->d_softc;
768 	sx_assert(&sc->sc_lock, SX_LOCKED);
769 
770 	if (sc->sc_type != G_MIRROR_TYPE_AUTOMATIC)
771 		return;
772 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_WIPE) == 0)
773 		g_mirror_fill_metadata(sc, disk, &md);
774 	error = g_mirror_write_metadata(disk, &md);
775 	if (error == 0) {
776 		G_MIRROR_DEBUG(2, "Metadata on %s updated.",
777 		    g_mirror_get_diskname(disk));
778 	} else {
779 		G_MIRROR_DEBUG(0,
780 		    "Cannot update metadata on disk %s (error=%d).",
781 		    g_mirror_get_diskname(disk), error);
782 	}
783 }
784 
785 static void
786 g_mirror_bump_syncid(struct g_mirror_softc *sc)
787 {
788 	struct g_mirror_disk *disk;
789 
790 	g_topology_assert_not();
791 	sx_assert(&sc->sc_lock, SX_XLOCKED);
792 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
793 	    ("%s called with no active disks (device=%s).", __func__,
794 	    sc->sc_name));
795 
796 	sc->sc_syncid++;
797 	G_MIRROR_DEBUG(1, "Device %s: syncid bumped to %u.", sc->sc_name,
798 	    sc->sc_syncid);
799 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
800 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
801 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
802 			disk->d_sync.ds_syncid = sc->sc_syncid;
803 			g_mirror_update_metadata(disk);
804 		}
805 	}
806 }
807 
808 static void
809 g_mirror_bump_genid(struct g_mirror_softc *sc)
810 {
811 	struct g_mirror_disk *disk;
812 
813 	g_topology_assert_not();
814 	sx_assert(&sc->sc_lock, SX_XLOCKED);
815 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
816 	    ("%s called with no active disks (device=%s).", __func__,
817 	    sc->sc_name));
818 
819 	sc->sc_genid++;
820 	G_MIRROR_DEBUG(1, "Device %s: genid bumped to %u.", sc->sc_name,
821 	    sc->sc_genid);
822 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
823 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
824 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
825 			disk->d_genid = sc->sc_genid;
826 			g_mirror_update_metadata(disk);
827 		}
828 	}
829 }
830 
831 static int
832 g_mirror_idle(struct g_mirror_softc *sc, int acw)
833 {
834 	struct g_mirror_disk *disk;
835 	int timeout;
836 
837 	g_topology_assert_not();
838 	sx_assert(&sc->sc_lock, SX_XLOCKED);
839 
840 	if (sc->sc_provider == NULL)
841 		return (0);
842 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
843 		return (0);
844 	if (sc->sc_idle)
845 		return (0);
846 	if (sc->sc_writes > 0)
847 		return (0);
848 	if (acw > 0 || (acw == -1 && sc->sc_provider->acw > 0)) {
849 		timeout = g_mirror_idletime - (time_uptime - sc->sc_last_write);
850 		if (!g_mirror_shutdown && timeout > 0)
851 			return (timeout);
852 	}
853 	sc->sc_idle = 1;
854 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
855 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
856 			continue;
857 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as clean.",
858 		    g_mirror_get_diskname(disk), sc->sc_name);
859 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
860 		g_mirror_update_metadata(disk);
861 	}
862 	return (0);
863 }
864 
865 static void
866 g_mirror_unidle(struct g_mirror_softc *sc)
867 {
868 	struct g_mirror_disk *disk;
869 
870 	g_topology_assert_not();
871 	sx_assert(&sc->sc_lock, SX_XLOCKED);
872 
873 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
874 		return;
875 	sc->sc_idle = 0;
876 	sc->sc_last_write = time_uptime;
877 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
878 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
879 			continue;
880 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as dirty.",
881 		    g_mirror_get_diskname(disk), sc->sc_name);
882 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
883 		g_mirror_update_metadata(disk);
884 	}
885 }
886 
887 static void
888 g_mirror_flush_done(struct bio *bp)
889 {
890 	struct g_mirror_softc *sc;
891 	struct bio *pbp;
892 
893 	pbp = bp->bio_parent;
894 	sc = pbp->bio_to->private;
895 	mtx_lock(&sc->sc_done_mtx);
896 	if (pbp->bio_error == 0)
897 		pbp->bio_error = bp->bio_error;
898 	pbp->bio_completed += bp->bio_completed;
899 	pbp->bio_inbed++;
900 	if (pbp->bio_children == pbp->bio_inbed) {
901 		mtx_unlock(&sc->sc_done_mtx);
902 		g_io_deliver(pbp, pbp->bio_error);
903 	} else
904 		mtx_unlock(&sc->sc_done_mtx);
905 	g_destroy_bio(bp);
906 }
907 
908 static void
909 g_mirror_done(struct bio *bp)
910 {
911 	struct g_mirror_softc *sc;
912 
913 	sc = bp->bio_from->geom->softc;
914 	bp->bio_cflags = G_MIRROR_BIO_FLAG_REGULAR;
915 	mtx_lock(&sc->sc_queue_mtx);
916 	bioq_insert_tail(&sc->sc_queue, bp);
917 	mtx_unlock(&sc->sc_queue_mtx);
918 	wakeup(sc);
919 }
920 
921 static void
922 g_mirror_regular_request(struct bio *bp)
923 {
924 	struct g_mirror_softc *sc;
925 	struct g_mirror_disk *disk;
926 	struct bio *pbp;
927 
928 	g_topology_assert_not();
929 
930 	pbp = bp->bio_parent;
931 	sc = pbp->bio_to->private;
932 	bp->bio_from->index--;
933 	if (bp->bio_cmd == BIO_WRITE)
934 		sc->sc_writes--;
935 	disk = bp->bio_from->private;
936 	if (disk == NULL) {
937 		g_topology_lock();
938 		g_mirror_kill_consumer(sc, bp->bio_from);
939 		g_topology_unlock();
940 	}
941 
942 	if (bp->bio_cmd == BIO_READ)
943 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_regular_request_read,
944 		    bp->bio_error);
945 	else if (bp->bio_cmd == BIO_WRITE)
946 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_regular_request_write,
947 		    bp->bio_error);
948 
949 	pbp->bio_inbed++;
950 	KASSERT(pbp->bio_inbed <= pbp->bio_children,
951 	    ("bio_inbed (%u) is bigger than bio_children (%u).", pbp->bio_inbed,
952 	    pbp->bio_children));
953 	if (bp->bio_error == 0 && pbp->bio_error == 0) {
954 		G_MIRROR_LOGREQ(3, bp, "Request delivered.");
955 		g_destroy_bio(bp);
956 		if (pbp->bio_children == pbp->bio_inbed) {
957 			G_MIRROR_LOGREQ(3, pbp, "Request delivered.");
958 			pbp->bio_completed = pbp->bio_length;
959 			if (pbp->bio_cmd == BIO_WRITE ||
960 			    pbp->bio_cmd == BIO_DELETE) {
961 				bioq_remove(&sc->sc_inflight, pbp);
962 				/* Release delayed sync requests if possible. */
963 				g_mirror_sync_release(sc);
964 			}
965 			g_io_deliver(pbp, pbp->bio_error);
966 		}
967 		return;
968 	} else if (bp->bio_error != 0) {
969 		if (pbp->bio_error == 0)
970 			pbp->bio_error = bp->bio_error;
971 		if (disk != NULL) {
972 			if ((disk->d_flags & G_MIRROR_DISK_FLAG_BROKEN) == 0) {
973 				disk->d_flags |= G_MIRROR_DISK_FLAG_BROKEN;
974 				G_MIRROR_LOGREQ(0, bp,
975 				    "Request failed (error=%d).",
976 				    bp->bio_error);
977 			} else {
978 				G_MIRROR_LOGREQ(1, bp,
979 				    "Request failed (error=%d).",
980 				    bp->bio_error);
981 			}
982 			if (g_mirror_disconnect_on_failure &&
983 			    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 1)
984 			{
985 				sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
986 				g_mirror_event_send(disk,
987 				    G_MIRROR_DISK_STATE_DISCONNECTED,
988 				    G_MIRROR_EVENT_DONTWAIT);
989 			}
990 		}
991 		switch (pbp->bio_cmd) {
992 		case BIO_DELETE:
993 		case BIO_WRITE:
994 			pbp->bio_inbed--;
995 			pbp->bio_children--;
996 			break;
997 		}
998 	}
999 	g_destroy_bio(bp);
1000 
1001 	switch (pbp->bio_cmd) {
1002 	case BIO_READ:
1003 		if (pbp->bio_inbed < pbp->bio_children)
1004 			break;
1005 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 1)
1006 			g_io_deliver(pbp, pbp->bio_error);
1007 		else {
1008 			pbp->bio_error = 0;
1009 			mtx_lock(&sc->sc_queue_mtx);
1010 			bioq_insert_tail(&sc->sc_queue, pbp);
1011 			mtx_unlock(&sc->sc_queue_mtx);
1012 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
1013 			wakeup(sc);
1014 		}
1015 		break;
1016 	case BIO_DELETE:
1017 	case BIO_WRITE:
1018 		if (pbp->bio_children == 0) {
1019 			/*
1020 			 * All requests failed.
1021 			 */
1022 		} else if (pbp->bio_inbed < pbp->bio_children) {
1023 			/* Do nothing. */
1024 			break;
1025 		} else if (pbp->bio_children == pbp->bio_inbed) {
1026 			/* Some requests succeeded. */
1027 			pbp->bio_error = 0;
1028 			pbp->bio_completed = pbp->bio_length;
1029 		}
1030 		bioq_remove(&sc->sc_inflight, pbp);
1031 		/* Release delayed sync requests if possible. */
1032 		g_mirror_sync_release(sc);
1033 		g_io_deliver(pbp, pbp->bio_error);
1034 		break;
1035 	default:
1036 		KASSERT(1 == 0, ("Invalid request: %u.", pbp->bio_cmd));
1037 		break;
1038 	}
1039 }
1040 
1041 static void
1042 g_mirror_sync_done(struct bio *bp)
1043 {
1044 	struct g_mirror_softc *sc;
1045 
1046 	G_MIRROR_LOGREQ(3, bp, "Synchronization request delivered.");
1047 	sc = bp->bio_from->geom->softc;
1048 	bp->bio_cflags = G_MIRROR_BIO_FLAG_SYNC;
1049 	mtx_lock(&sc->sc_queue_mtx);
1050 	bioq_insert_tail(&sc->sc_queue, bp);
1051 	mtx_unlock(&sc->sc_queue_mtx);
1052 	wakeup(sc);
1053 }
1054 
1055 static void
1056 g_mirror_candelete(struct bio *bp)
1057 {
1058 	struct g_mirror_softc *sc;
1059 	struct g_mirror_disk *disk;
1060 	int *val;
1061 
1062 	sc = bp->bio_to->private;
1063 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1064 		if (disk->d_flags & G_MIRROR_DISK_FLAG_CANDELETE)
1065 			break;
1066 	}
1067 	val = (int *)bp->bio_data;
1068 	*val = (disk != NULL);
1069 	g_io_deliver(bp, 0);
1070 }
1071 
1072 static void
1073 g_mirror_kernel_dump(struct bio *bp)
1074 {
1075 	struct g_mirror_softc *sc;
1076 	struct g_mirror_disk *disk;
1077 	struct bio *cbp;
1078 	struct g_kerneldump *gkd;
1079 
1080 	/*
1081 	 * We configure dumping to the first component, because this component
1082 	 * will be used for reading with 'prefer' balance algorithm.
1083 	 * If the component with the highest priority is currently disconnected
1084 	 * we will not be able to read the dump after the reboot if it will be
1085 	 * connected and synchronized later. Can we do something better?
1086 	 */
1087 	sc = bp->bio_to->private;
1088 	disk = LIST_FIRST(&sc->sc_disks);
1089 
1090 	gkd = (struct g_kerneldump *)bp->bio_data;
1091 	if (gkd->length > bp->bio_to->mediasize)
1092 		gkd->length = bp->bio_to->mediasize;
1093 	cbp = g_clone_bio(bp);
1094 	if (cbp == NULL) {
1095 		g_io_deliver(bp, ENOMEM);
1096 		return;
1097 	}
1098 	cbp->bio_done = g_std_done;
1099 	g_io_request(cbp, disk->d_consumer);
1100 	G_MIRROR_DEBUG(1, "Kernel dump will go to %s.",
1101 	    g_mirror_get_diskname(disk));
1102 }
1103 
1104 static void
1105 g_mirror_flush(struct g_mirror_softc *sc, struct bio *bp)
1106 {
1107 	struct bio_queue_head queue;
1108 	struct g_mirror_disk *disk;
1109 	struct g_consumer *cp;
1110 	struct bio *cbp;
1111 
1112 	bioq_init(&queue);
1113 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1114 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1115 			continue;
1116 		cbp = g_clone_bio(bp);
1117 		if (cbp == NULL) {
1118 			while ((cbp = bioq_takefirst(&queue)) != NULL)
1119 				g_destroy_bio(cbp);
1120 			if (bp->bio_error == 0)
1121 				bp->bio_error = ENOMEM;
1122 			g_io_deliver(bp, bp->bio_error);
1123 			return;
1124 		}
1125 		bioq_insert_tail(&queue, cbp);
1126 		cbp->bio_done = g_mirror_flush_done;
1127 		cbp->bio_caller1 = disk;
1128 		cbp->bio_to = disk->d_consumer->provider;
1129 	}
1130 	while ((cbp = bioq_takefirst(&queue)) != NULL) {
1131 		G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1132 		disk = cbp->bio_caller1;
1133 		cbp->bio_caller1 = NULL;
1134 		cp = disk->d_consumer;
1135 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1136 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1137 		    cp->acr, cp->acw, cp->ace));
1138 		g_io_request(cbp, disk->d_consumer);
1139 	}
1140 }
1141 
1142 static void
1143 g_mirror_start(struct bio *bp)
1144 {
1145 	struct g_mirror_softc *sc;
1146 
1147 	sc = bp->bio_to->private;
1148 	/*
1149 	 * If sc == NULL or there are no valid disks, provider's error
1150 	 * should be set and g_mirror_start() should not be called at all.
1151 	 */
1152 	KASSERT(sc != NULL && sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
1153 	    ("Provider's error should be set (error=%d)(mirror=%s).",
1154 	    bp->bio_to->error, bp->bio_to->name));
1155 	G_MIRROR_LOGREQ(3, bp, "Request received.");
1156 
1157 	switch (bp->bio_cmd) {
1158 	case BIO_READ:
1159 	case BIO_WRITE:
1160 	case BIO_DELETE:
1161 		break;
1162 	case BIO_FLUSH:
1163 		g_mirror_flush(sc, bp);
1164 		return;
1165 	case BIO_GETATTR:
1166 		if (!strcmp(bp->bio_attribute, "GEOM::candelete")) {
1167 			g_mirror_candelete(bp);
1168 			return;
1169 		} else if (strcmp("GEOM::kerneldump", bp->bio_attribute) == 0) {
1170 			g_mirror_kernel_dump(bp);
1171 			return;
1172 		}
1173 		/* FALLTHROUGH */
1174 	default:
1175 		g_io_deliver(bp, EOPNOTSUPP);
1176 		return;
1177 	}
1178 	mtx_lock(&sc->sc_queue_mtx);
1179 	bioq_insert_tail(&sc->sc_queue, bp);
1180 	mtx_unlock(&sc->sc_queue_mtx);
1181 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
1182 	wakeup(sc);
1183 }
1184 
1185 /*
1186  * Return TRUE if the given request is colliding with a in-progress
1187  * synchronization request.
1188  */
1189 static int
1190 g_mirror_sync_collision(struct g_mirror_softc *sc, struct bio *bp)
1191 {
1192 	struct g_mirror_disk *disk;
1193 	struct bio *sbp;
1194 	off_t rstart, rend, sstart, send;
1195 	u_int i;
1196 
1197 	if (sc->sc_sync.ds_ndisks == 0)
1198 		return (0);
1199 	rstart = bp->bio_offset;
1200 	rend = bp->bio_offset + bp->bio_length;
1201 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1202 		if (disk->d_state != G_MIRROR_DISK_STATE_SYNCHRONIZING)
1203 			continue;
1204 		for (i = 0; i < g_mirror_syncreqs; i++) {
1205 			sbp = disk->d_sync.ds_bios[i];
1206 			if (sbp == NULL)
1207 				continue;
1208 			sstart = sbp->bio_offset;
1209 			send = sbp->bio_offset + sbp->bio_length;
1210 			if (rend > sstart && rstart < send)
1211 				return (1);
1212 		}
1213 	}
1214 	return (0);
1215 }
1216 
1217 /*
1218  * Return TRUE if the given sync request is colliding with a in-progress regular
1219  * request.
1220  */
1221 static int
1222 g_mirror_regular_collision(struct g_mirror_softc *sc, struct bio *sbp)
1223 {
1224 	off_t rstart, rend, sstart, send;
1225 	struct bio *bp;
1226 
1227 	if (sc->sc_sync.ds_ndisks == 0)
1228 		return (0);
1229 	sstart = sbp->bio_offset;
1230 	send = sbp->bio_offset + sbp->bio_length;
1231 	TAILQ_FOREACH(bp, &sc->sc_inflight.queue, bio_queue) {
1232 		rstart = bp->bio_offset;
1233 		rend = bp->bio_offset + bp->bio_length;
1234 		if (rend > sstart && rstart < send)
1235 			return (1);
1236 	}
1237 	return (0);
1238 }
1239 
1240 /*
1241  * Puts request onto delayed queue.
1242  */
1243 static void
1244 g_mirror_regular_delay(struct g_mirror_softc *sc, struct bio *bp)
1245 {
1246 
1247 	G_MIRROR_LOGREQ(2, bp, "Delaying request.");
1248 	bioq_insert_head(&sc->sc_regular_delayed, bp);
1249 }
1250 
1251 /*
1252  * Puts synchronization request onto delayed queue.
1253  */
1254 static void
1255 g_mirror_sync_delay(struct g_mirror_softc *sc, struct bio *bp)
1256 {
1257 
1258 	G_MIRROR_LOGREQ(2, bp, "Delaying synchronization request.");
1259 	bioq_insert_tail(&sc->sc_sync_delayed, bp);
1260 }
1261 
1262 /*
1263  * Releases delayed regular requests which don't collide anymore with sync
1264  * requests.
1265  */
1266 static void
1267 g_mirror_regular_release(struct g_mirror_softc *sc)
1268 {
1269 	struct bio *bp, *bp2;
1270 
1271 	TAILQ_FOREACH_SAFE(bp, &sc->sc_regular_delayed.queue, bio_queue, bp2) {
1272 		if (g_mirror_sync_collision(sc, bp))
1273 			continue;
1274 		bioq_remove(&sc->sc_regular_delayed, bp);
1275 		G_MIRROR_LOGREQ(2, bp, "Releasing delayed request (%p).", bp);
1276 		mtx_lock(&sc->sc_queue_mtx);
1277 		bioq_insert_head(&sc->sc_queue, bp);
1278 		mtx_unlock(&sc->sc_queue_mtx);
1279 	}
1280 }
1281 
1282 /*
1283  * Releases delayed sync requests which don't collide anymore with regular
1284  * requests.
1285  */
1286 static void
1287 g_mirror_sync_release(struct g_mirror_softc *sc)
1288 {
1289 	struct bio *bp, *bp2;
1290 
1291 	TAILQ_FOREACH_SAFE(bp, &sc->sc_sync_delayed.queue, bio_queue, bp2) {
1292 		if (g_mirror_regular_collision(sc, bp))
1293 			continue;
1294 		bioq_remove(&sc->sc_sync_delayed, bp);
1295 		G_MIRROR_LOGREQ(2, bp,
1296 		    "Releasing delayed synchronization request.");
1297 		g_io_request(bp, bp->bio_from);
1298 	}
1299 }
1300 
1301 /*
1302  * Free a synchronization request and clear its slot in the array.
1303  */
1304 static void
1305 g_mirror_sync_request_free(struct g_mirror_disk *disk, struct bio *bp)
1306 {
1307 	int i;
1308 
1309 	if (disk != NULL && disk->d_sync.ds_bios != NULL) {
1310 		i = (int)(uintptr_t)bp->bio_caller1;
1311 		disk->d_sync.ds_bios[i] = NULL;
1312 	}
1313 	free(bp->bio_data, M_MIRROR);
1314 	g_destroy_bio(bp);
1315 }
1316 
1317 /*
1318  * Handle synchronization requests.
1319  * Every synchronization request is two-steps process: first, READ request is
1320  * send to active provider and then WRITE request (with read data) to the provider
1321  * being synchronized. When WRITE is finished, new synchronization request is
1322  * send.
1323  */
1324 static void
1325 g_mirror_sync_request(struct bio *bp)
1326 {
1327 	struct g_mirror_softc *sc;
1328 	struct g_mirror_disk *disk;
1329 	struct g_mirror_disk_sync *sync;
1330 
1331 	bp->bio_from->index--;
1332 	sc = bp->bio_from->geom->softc;
1333 	disk = bp->bio_from->private;
1334 	if (disk == NULL) {
1335 		sx_xunlock(&sc->sc_lock); /* Avoid recursion on sc_lock. */
1336 		g_topology_lock();
1337 		g_mirror_kill_consumer(sc, bp->bio_from);
1338 		g_topology_unlock();
1339 		g_mirror_sync_request_free(NULL, bp);
1340 		sx_xlock(&sc->sc_lock);
1341 		return;
1342 	}
1343 
1344 	/*
1345 	 * Synchronization request.
1346 	 */
1347 	switch (bp->bio_cmd) {
1348 	case BIO_READ:
1349 	    {
1350 		struct g_consumer *cp;
1351 
1352 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_sync_request_read,
1353 		    bp->bio_error);
1354 
1355 		if (bp->bio_error != 0) {
1356 			G_MIRROR_LOGREQ(0, bp,
1357 			    "Synchronization request failed (error=%d).",
1358 			    bp->bio_error);
1359 			g_mirror_sync_request_free(disk, bp);
1360 			return;
1361 		}
1362 		G_MIRROR_LOGREQ(3, bp,
1363 		    "Synchronization request half-finished.");
1364 		bp->bio_cmd = BIO_WRITE;
1365 		bp->bio_cflags = 0;
1366 		cp = disk->d_consumer;
1367 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1368 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1369 		    cp->acr, cp->acw, cp->ace));
1370 		cp->index++;
1371 		g_io_request(bp, cp);
1372 		return;
1373 	    }
1374 	case BIO_WRITE:
1375 	    {
1376 		off_t offset;
1377 		void *data;
1378 		int i;
1379 
1380 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_sync_request_write,
1381 		    bp->bio_error);
1382 
1383 		if (bp->bio_error != 0) {
1384 			G_MIRROR_LOGREQ(0, bp,
1385 			    "Synchronization request failed (error=%d).",
1386 			    bp->bio_error);
1387 			g_mirror_sync_request_free(disk, bp);
1388 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
1389 			g_mirror_event_send(disk,
1390 			    G_MIRROR_DISK_STATE_DISCONNECTED,
1391 			    G_MIRROR_EVENT_DONTWAIT);
1392 			return;
1393 		}
1394 		G_MIRROR_LOGREQ(3, bp, "Synchronization request finished.");
1395 		sync = &disk->d_sync;
1396 		if (sync->ds_offset >= sc->sc_mediasize ||
1397 		    sync->ds_consumer == NULL ||
1398 		    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1399 			/* Don't send more synchronization requests. */
1400 			sync->ds_inflight--;
1401 			g_mirror_sync_request_free(disk, bp);
1402 			if (sync->ds_inflight > 0)
1403 				return;
1404 			if (sync->ds_consumer == NULL ||
1405 			    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1406 				return;
1407 			}
1408 			/* Disk up-to-date, activate it. */
1409 			g_mirror_event_send(disk, G_MIRROR_DISK_STATE_ACTIVE,
1410 			    G_MIRROR_EVENT_DONTWAIT);
1411 			return;
1412 		}
1413 
1414 		/* Send next synchronization request. */
1415 		data = bp->bio_data;
1416 		g_reset_bio(bp);
1417 		bp->bio_cmd = BIO_READ;
1418 		bp->bio_offset = sync->ds_offset;
1419 		bp->bio_length = MIN(MAXPHYS, sc->sc_mediasize - bp->bio_offset);
1420 		sync->ds_offset += bp->bio_length;
1421 		bp->bio_done = g_mirror_sync_done;
1422 		bp->bio_data = data;
1423 		bp->bio_from = sync->ds_consumer;
1424 		bp->bio_to = sc->sc_provider;
1425 		G_MIRROR_LOGREQ(3, bp, "Sending synchronization request.");
1426 		sync->ds_consumer->index++;
1427 		/*
1428 		 * Delay the request if it is colliding with a regular request.
1429 		 */
1430 		if (g_mirror_regular_collision(sc, bp))
1431 			g_mirror_sync_delay(sc, bp);
1432 		else
1433 			g_io_request(bp, sync->ds_consumer);
1434 
1435 		/* Release delayed requests if possible. */
1436 		g_mirror_regular_release(sc);
1437 
1438 		/* Find the smallest offset */
1439 		offset = sc->sc_mediasize;
1440 		for (i = 0; i < g_mirror_syncreqs; i++) {
1441 			bp = sync->ds_bios[i];
1442 			if (bp->bio_offset < offset)
1443 				offset = bp->bio_offset;
1444 		}
1445 		if (sync->ds_offset_done + (MAXPHYS * 100) < offset) {
1446 			/* Update offset_done on every 100 blocks. */
1447 			sync->ds_offset_done = offset;
1448 			g_mirror_update_metadata(disk);
1449 		}
1450 		return;
1451 	    }
1452 	default:
1453 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1454 		    bp->bio_cmd, sc->sc_name));
1455 		break;
1456 	}
1457 }
1458 
1459 static void
1460 g_mirror_request_prefer(struct g_mirror_softc *sc, struct bio *bp)
1461 {
1462 	struct g_mirror_disk *disk;
1463 	struct g_consumer *cp;
1464 	struct bio *cbp;
1465 
1466 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1467 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE)
1468 			break;
1469 	}
1470 	if (disk == NULL) {
1471 		if (bp->bio_error == 0)
1472 			bp->bio_error = ENXIO;
1473 		g_io_deliver(bp, bp->bio_error);
1474 		return;
1475 	}
1476 	cbp = g_clone_bio(bp);
1477 	if (cbp == NULL) {
1478 		if (bp->bio_error == 0)
1479 			bp->bio_error = ENOMEM;
1480 		g_io_deliver(bp, bp->bio_error);
1481 		return;
1482 	}
1483 	/*
1484 	 * Fill in the component buf structure.
1485 	 */
1486 	cp = disk->d_consumer;
1487 	cbp->bio_done = g_mirror_done;
1488 	cbp->bio_to = cp->provider;
1489 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1490 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1491 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1492 	    cp->acw, cp->ace));
1493 	cp->index++;
1494 	g_io_request(cbp, cp);
1495 }
1496 
1497 static void
1498 g_mirror_request_round_robin(struct g_mirror_softc *sc, struct bio *bp)
1499 {
1500 	struct g_mirror_disk *disk;
1501 	struct g_consumer *cp;
1502 	struct bio *cbp;
1503 
1504 	disk = g_mirror_get_disk(sc);
1505 	if (disk == NULL) {
1506 		if (bp->bio_error == 0)
1507 			bp->bio_error = ENXIO;
1508 		g_io_deliver(bp, bp->bio_error);
1509 		return;
1510 	}
1511 	cbp = g_clone_bio(bp);
1512 	if (cbp == NULL) {
1513 		if (bp->bio_error == 0)
1514 			bp->bio_error = ENOMEM;
1515 		g_io_deliver(bp, bp->bio_error);
1516 		return;
1517 	}
1518 	/*
1519 	 * Fill in the component buf structure.
1520 	 */
1521 	cp = disk->d_consumer;
1522 	cbp->bio_done = g_mirror_done;
1523 	cbp->bio_to = cp->provider;
1524 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1525 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1526 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1527 	    cp->acw, cp->ace));
1528 	cp->index++;
1529 	g_io_request(cbp, cp);
1530 }
1531 
1532 #define TRACK_SIZE  (1 * 1024 * 1024)
1533 #define LOAD_SCALE	256
1534 #define ABS(x)		(((x) >= 0) ? (x) : (-(x)))
1535 
1536 static void
1537 g_mirror_request_load(struct g_mirror_softc *sc, struct bio *bp)
1538 {
1539 	struct g_mirror_disk *disk, *dp;
1540 	struct g_consumer *cp;
1541 	struct bio *cbp;
1542 	int prio, best;
1543 
1544 	/* Find a disk with the smallest load. */
1545 	disk = NULL;
1546 	best = INT_MAX;
1547 	LIST_FOREACH(dp, &sc->sc_disks, d_next) {
1548 		if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1549 			continue;
1550 		prio = dp->load;
1551 		/* If disk head is precisely in position - highly prefer it. */
1552 		if (dp->d_last_offset == bp->bio_offset)
1553 			prio -= 2 * LOAD_SCALE;
1554 		else
1555 		/* If disk head is close to position - prefer it. */
1556 		if (ABS(dp->d_last_offset - bp->bio_offset) < TRACK_SIZE)
1557 			prio -= 1 * LOAD_SCALE;
1558 		if (prio <= best) {
1559 			disk = dp;
1560 			best = prio;
1561 		}
1562 	}
1563 	KASSERT(disk != NULL, ("NULL disk for %s.", sc->sc_name));
1564 	cbp = g_clone_bio(bp);
1565 	if (cbp == NULL) {
1566 		if (bp->bio_error == 0)
1567 			bp->bio_error = ENOMEM;
1568 		g_io_deliver(bp, bp->bio_error);
1569 		return;
1570 	}
1571 	/*
1572 	 * Fill in the component buf structure.
1573 	 */
1574 	cp = disk->d_consumer;
1575 	cbp->bio_done = g_mirror_done;
1576 	cbp->bio_to = cp->provider;
1577 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1578 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1579 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1580 	    cp->acw, cp->ace));
1581 	cp->index++;
1582 	/* Remember last head position */
1583 	disk->d_last_offset = bp->bio_offset + bp->bio_length;
1584 	/* Update loads. */
1585 	LIST_FOREACH(dp, &sc->sc_disks, d_next) {
1586 		dp->load = (dp->d_consumer->index * LOAD_SCALE +
1587 		    dp->load * 7) / 8;
1588 	}
1589 	g_io_request(cbp, cp);
1590 }
1591 
1592 static void
1593 g_mirror_request_split(struct g_mirror_softc *sc, struct bio *bp)
1594 {
1595 	struct bio_queue_head queue;
1596 	struct g_mirror_disk *disk;
1597 	struct g_consumer *cp;
1598 	struct bio *cbp;
1599 	off_t left, mod, offset, slice;
1600 	u_char *data;
1601 	u_int ndisks;
1602 
1603 	if (bp->bio_length <= sc->sc_slice) {
1604 		g_mirror_request_round_robin(sc, bp);
1605 		return;
1606 	}
1607 	ndisks = g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE);
1608 	slice = bp->bio_length / ndisks;
1609 	mod = slice % sc->sc_provider->sectorsize;
1610 	if (mod != 0)
1611 		slice += sc->sc_provider->sectorsize - mod;
1612 	/*
1613 	 * Allocate all bios before sending any request, so we can
1614 	 * return ENOMEM in nice and clean way.
1615 	 */
1616 	left = bp->bio_length;
1617 	offset = bp->bio_offset;
1618 	data = bp->bio_data;
1619 	bioq_init(&queue);
1620 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1621 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1622 			continue;
1623 		cbp = g_clone_bio(bp);
1624 		if (cbp == NULL) {
1625 			while ((cbp = bioq_takefirst(&queue)) != NULL)
1626 				g_destroy_bio(cbp);
1627 			if (bp->bio_error == 0)
1628 				bp->bio_error = ENOMEM;
1629 			g_io_deliver(bp, bp->bio_error);
1630 			return;
1631 		}
1632 		bioq_insert_tail(&queue, cbp);
1633 		cbp->bio_done = g_mirror_done;
1634 		cbp->bio_caller1 = disk;
1635 		cbp->bio_to = disk->d_consumer->provider;
1636 		cbp->bio_offset = offset;
1637 		cbp->bio_data = data;
1638 		cbp->bio_length = MIN(left, slice);
1639 		left -= cbp->bio_length;
1640 		if (left == 0)
1641 			break;
1642 		offset += cbp->bio_length;
1643 		data += cbp->bio_length;
1644 	}
1645 	while ((cbp = bioq_takefirst(&queue)) != NULL) {
1646 		G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1647 		disk = cbp->bio_caller1;
1648 		cbp->bio_caller1 = NULL;
1649 		cp = disk->d_consumer;
1650 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1651 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1652 		    cp->acr, cp->acw, cp->ace));
1653 		disk->d_consumer->index++;
1654 		g_io_request(cbp, disk->d_consumer);
1655 	}
1656 }
1657 
1658 static void
1659 g_mirror_register_request(struct bio *bp)
1660 {
1661 	struct g_mirror_softc *sc;
1662 
1663 	sc = bp->bio_to->private;
1664 	switch (bp->bio_cmd) {
1665 	case BIO_READ:
1666 		switch (sc->sc_balance) {
1667 		case G_MIRROR_BALANCE_LOAD:
1668 			g_mirror_request_load(sc, bp);
1669 			break;
1670 		case G_MIRROR_BALANCE_PREFER:
1671 			g_mirror_request_prefer(sc, bp);
1672 			break;
1673 		case G_MIRROR_BALANCE_ROUND_ROBIN:
1674 			g_mirror_request_round_robin(sc, bp);
1675 			break;
1676 		case G_MIRROR_BALANCE_SPLIT:
1677 			g_mirror_request_split(sc, bp);
1678 			break;
1679 		}
1680 		return;
1681 	case BIO_WRITE:
1682 	case BIO_DELETE:
1683 	    {
1684 		struct g_mirror_disk *disk;
1685 		struct g_mirror_disk_sync *sync;
1686 		struct bio_queue_head queue;
1687 		struct g_consumer *cp;
1688 		struct bio *cbp;
1689 
1690 		/*
1691 		 * Delay the request if it is colliding with a synchronization
1692 		 * request.
1693 		 */
1694 		if (g_mirror_sync_collision(sc, bp)) {
1695 			g_mirror_regular_delay(sc, bp);
1696 			return;
1697 		}
1698 
1699 		if (sc->sc_idle)
1700 			g_mirror_unidle(sc);
1701 		else
1702 			sc->sc_last_write = time_uptime;
1703 
1704 		/*
1705 		 * Bump syncid on first write.
1706 		 */
1707 		if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0) {
1708 			sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
1709 			g_mirror_bump_syncid(sc);
1710 		}
1711 
1712 		/*
1713 		 * Allocate all bios before sending any request, so we can
1714 		 * return ENOMEM in nice and clean way.
1715 		 */
1716 		bioq_init(&queue);
1717 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1718 			sync = &disk->d_sync;
1719 			switch (disk->d_state) {
1720 			case G_MIRROR_DISK_STATE_ACTIVE:
1721 				break;
1722 			case G_MIRROR_DISK_STATE_SYNCHRONIZING:
1723 				if (bp->bio_offset >= sync->ds_offset)
1724 					continue;
1725 				break;
1726 			default:
1727 				continue;
1728 			}
1729 			if (bp->bio_cmd == BIO_DELETE &&
1730 			    (disk->d_flags & G_MIRROR_DISK_FLAG_CANDELETE) == 0)
1731 				continue;
1732 			cbp = g_clone_bio(bp);
1733 			if (cbp == NULL) {
1734 				while ((cbp = bioq_takefirst(&queue)) != NULL)
1735 					g_destroy_bio(cbp);
1736 				if (bp->bio_error == 0)
1737 					bp->bio_error = ENOMEM;
1738 				g_io_deliver(bp, bp->bio_error);
1739 				return;
1740 			}
1741 			bioq_insert_tail(&queue, cbp);
1742 			cbp->bio_done = g_mirror_done;
1743 			cp = disk->d_consumer;
1744 			cbp->bio_caller1 = cp;
1745 			cbp->bio_to = cp->provider;
1746 			KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1747 			    ("Consumer %s not opened (r%dw%de%d).",
1748 			    cp->provider->name, cp->acr, cp->acw, cp->ace));
1749 		}
1750 		if (bioq_first(&queue) == NULL) {
1751 			g_io_deliver(bp, EOPNOTSUPP);
1752 			return;
1753 		}
1754 		while ((cbp = bioq_takefirst(&queue)) != NULL) {
1755 			G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1756 			cp = cbp->bio_caller1;
1757 			cbp->bio_caller1 = NULL;
1758 			cp->index++;
1759 			sc->sc_writes++;
1760 			g_io_request(cbp, cp);
1761 		}
1762 		/*
1763 		 * Put request onto inflight queue, so we can check if new
1764 		 * synchronization requests don't collide with it.
1765 		 */
1766 		bioq_insert_tail(&sc->sc_inflight, bp);
1767 		return;
1768 	    }
1769 	default:
1770 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1771 		    bp->bio_cmd, sc->sc_name));
1772 		break;
1773 	}
1774 }
1775 
1776 static int
1777 g_mirror_can_destroy(struct g_mirror_softc *sc)
1778 {
1779 	struct g_geom *gp;
1780 	struct g_consumer *cp;
1781 
1782 	g_topology_assert();
1783 	gp = sc->sc_geom;
1784 	if (gp->softc == NULL)
1785 		return (1);
1786 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_TASTING) != 0)
1787 		return (0);
1788 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1789 		if (g_mirror_is_busy(sc, cp))
1790 			return (0);
1791 	}
1792 	gp = sc->sc_sync.ds_geom;
1793 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1794 		if (g_mirror_is_busy(sc, cp))
1795 			return (0);
1796 	}
1797 	G_MIRROR_DEBUG(2, "No I/O requests for %s, it can be destroyed.",
1798 	    sc->sc_name);
1799 	return (1);
1800 }
1801 
1802 static int
1803 g_mirror_try_destroy(struct g_mirror_softc *sc)
1804 {
1805 
1806 	if (sc->sc_rootmount != NULL) {
1807 		G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p", __LINE__,
1808 		    sc->sc_rootmount);
1809 		root_mount_rel(sc->sc_rootmount);
1810 		sc->sc_rootmount = NULL;
1811 	}
1812 	g_topology_lock();
1813 	if (!g_mirror_can_destroy(sc)) {
1814 		g_topology_unlock();
1815 		return (0);
1816 	}
1817 	sc->sc_geom->softc = NULL;
1818 	sc->sc_sync.ds_geom->softc = NULL;
1819 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_WAIT) != 0) {
1820 		g_topology_unlock();
1821 		G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1822 		    &sc->sc_worker);
1823 		/* Unlock sc_lock here, as it can be destroyed after wakeup. */
1824 		sx_xunlock(&sc->sc_lock);
1825 		wakeup(&sc->sc_worker);
1826 		sc->sc_worker = NULL;
1827 	} else {
1828 		g_topology_unlock();
1829 		g_mirror_destroy_device(sc);
1830 	}
1831 	return (1);
1832 }
1833 
1834 /*
1835  * Worker thread.
1836  */
1837 static void
1838 g_mirror_worker(void *arg)
1839 {
1840 	struct g_mirror_softc *sc;
1841 	struct g_mirror_event *ep;
1842 	struct bio *bp;
1843 	int timeout;
1844 
1845 	sc = arg;
1846 	thread_lock(curthread);
1847 	sched_prio(curthread, PRIBIO);
1848 	thread_unlock(curthread);
1849 
1850 	sx_xlock(&sc->sc_lock);
1851 	for (;;) {
1852 		G_MIRROR_DEBUG(5, "%s: Let's see...", __func__);
1853 		/*
1854 		 * First take a look at events.
1855 		 * This is important to handle events before any I/O requests.
1856 		 */
1857 		ep = g_mirror_event_get(sc);
1858 		if (ep != NULL) {
1859 			g_mirror_event_remove(sc, ep);
1860 			if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0) {
1861 				/* Update only device status. */
1862 				G_MIRROR_DEBUG(3,
1863 				    "Running event for device %s.",
1864 				    sc->sc_name);
1865 				ep->e_error = 0;
1866 				g_mirror_update_device(sc, true);
1867 			} else {
1868 				/* Update disk status. */
1869 				G_MIRROR_DEBUG(3, "Running event for disk %s.",
1870 				     g_mirror_get_diskname(ep->e_disk));
1871 				ep->e_error = g_mirror_update_disk(ep->e_disk,
1872 				    ep->e_state);
1873 				if (ep->e_error == 0)
1874 					g_mirror_update_device(sc, false);
1875 			}
1876 			if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0) {
1877 				KASSERT(ep->e_error == 0,
1878 				    ("Error cannot be handled."));
1879 				g_mirror_event_free(ep);
1880 			} else {
1881 				ep->e_flags |= G_MIRROR_EVENT_DONE;
1882 				G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1883 				    ep);
1884 				mtx_lock(&sc->sc_events_mtx);
1885 				wakeup(ep);
1886 				mtx_unlock(&sc->sc_events_mtx);
1887 			}
1888 			if ((sc->sc_flags &
1889 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1890 				if (g_mirror_try_destroy(sc)) {
1891 					curthread->td_pflags &= ~TDP_GEOM;
1892 					G_MIRROR_DEBUG(1, "Thread exiting.");
1893 					kproc_exit(0);
1894 				}
1895 			}
1896 			G_MIRROR_DEBUG(5, "%s: I'm here 1.", __func__);
1897 			continue;
1898 		}
1899 		/*
1900 		 * Check if we can mark array as CLEAN and if we can't take
1901 		 * how much seconds should we wait.
1902 		 */
1903 		timeout = g_mirror_idle(sc, -1);
1904 		/*
1905 		 * Now I/O requests.
1906 		 */
1907 		/* Get first request from the queue. */
1908 		mtx_lock(&sc->sc_queue_mtx);
1909 		bp = bioq_takefirst(&sc->sc_queue);
1910 		if (bp == NULL) {
1911 			if ((sc->sc_flags &
1912 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1913 				mtx_unlock(&sc->sc_queue_mtx);
1914 				if (g_mirror_try_destroy(sc)) {
1915 					curthread->td_pflags &= ~TDP_GEOM;
1916 					G_MIRROR_DEBUG(1, "Thread exiting.");
1917 					kproc_exit(0);
1918 				}
1919 				mtx_lock(&sc->sc_queue_mtx);
1920 			}
1921 			sx_xunlock(&sc->sc_lock);
1922 			/*
1923 			 * XXX: We can miss an event here, because an event
1924 			 *      can be added without sx-device-lock and without
1925 			 *      mtx-queue-lock. Maybe I should just stop using
1926 			 *      dedicated mutex for events synchronization and
1927 			 *      stick with the queue lock?
1928 			 *      The event will hang here until next I/O request
1929 			 *      or next event is received.
1930 			 */
1931 			MSLEEP(sc, &sc->sc_queue_mtx, PRIBIO | PDROP, "m:w1",
1932 			    timeout * hz);
1933 			sx_xlock(&sc->sc_lock);
1934 			G_MIRROR_DEBUG(5, "%s: I'm here 4.", __func__);
1935 			continue;
1936 		}
1937 		mtx_unlock(&sc->sc_queue_mtx);
1938 
1939 		if (bp->bio_from->geom == sc->sc_sync.ds_geom &&
1940 		    (bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0) {
1941 			g_mirror_sync_request(bp);	/* READ */
1942 		} else if (bp->bio_to != sc->sc_provider) {
1943 			if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_REGULAR) != 0)
1944 				g_mirror_regular_request(bp);
1945 			else if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0)
1946 				g_mirror_sync_request(bp);	/* WRITE */
1947 			else {
1948 				KASSERT(0,
1949 				    ("Invalid request cflags=0x%hx to=%s.",
1950 				    bp->bio_cflags, bp->bio_to->name));
1951 			}
1952 		} else {
1953 			g_mirror_register_request(bp);
1954 		}
1955 		G_MIRROR_DEBUG(5, "%s: I'm here 9.", __func__);
1956 	}
1957 }
1958 
1959 static void
1960 g_mirror_update_idle(struct g_mirror_softc *sc, struct g_mirror_disk *disk)
1961 {
1962 
1963 	sx_assert(&sc->sc_lock, SX_LOCKED);
1964 
1965 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
1966 		return;
1967 	if (!sc->sc_idle && (disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) == 0) {
1968 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as dirty.",
1969 		    g_mirror_get_diskname(disk), sc->sc_name);
1970 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1971 	} else if (sc->sc_idle &&
1972 	    (disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
1973 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as clean.",
1974 		    g_mirror_get_diskname(disk), sc->sc_name);
1975 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
1976 	}
1977 }
1978 
1979 static void
1980 g_mirror_sync_start(struct g_mirror_disk *disk)
1981 {
1982 	struct g_mirror_softc *sc;
1983 	struct g_consumer *cp;
1984 	struct bio *bp;
1985 	int error, i;
1986 
1987 	g_topology_assert_not();
1988 	sc = disk->d_softc;
1989 	sx_assert(&sc->sc_lock, SX_LOCKED);
1990 
1991 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
1992 	    ("Disk %s is not marked for synchronization.",
1993 	    g_mirror_get_diskname(disk)));
1994 	KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
1995 	    ("Device not in RUNNING state (%s, %u).", sc->sc_name,
1996 	    sc->sc_state));
1997 
1998 	sx_xunlock(&sc->sc_lock);
1999 	g_topology_lock();
2000 	cp = g_new_consumer(sc->sc_sync.ds_geom);
2001 	cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
2002 	error = g_attach(cp, sc->sc_provider);
2003 	KASSERT(error == 0,
2004 	    ("Cannot attach to %s (error=%d).", sc->sc_name, error));
2005 	error = g_access(cp, 1, 0, 0);
2006 	KASSERT(error == 0, ("Cannot open %s (error=%d).", sc->sc_name, error));
2007 	g_topology_unlock();
2008 	sx_xlock(&sc->sc_lock);
2009 
2010 	G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s.", sc->sc_name,
2011 	    g_mirror_get_diskname(disk));
2012 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) == 0)
2013 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
2014 	KASSERT(disk->d_sync.ds_consumer == NULL,
2015 	    ("Sync consumer already exists (device=%s, disk=%s).",
2016 	    sc->sc_name, g_mirror_get_diskname(disk)));
2017 
2018 	disk->d_sync.ds_consumer = cp;
2019 	disk->d_sync.ds_consumer->private = disk;
2020 	disk->d_sync.ds_consumer->index = 0;
2021 
2022 	/*
2023 	 * Allocate memory for synchronization bios and initialize them.
2024 	 */
2025 	disk->d_sync.ds_bios = malloc(sizeof(struct bio *) * g_mirror_syncreqs,
2026 	    M_MIRROR, M_WAITOK);
2027 	for (i = 0; i < g_mirror_syncreqs; i++) {
2028 		bp = g_alloc_bio();
2029 		disk->d_sync.ds_bios[i] = bp;
2030 		bp->bio_parent = NULL;
2031 		bp->bio_cmd = BIO_READ;
2032 		bp->bio_data = malloc(MAXPHYS, M_MIRROR, M_WAITOK);
2033 		bp->bio_cflags = 0;
2034 		bp->bio_offset = disk->d_sync.ds_offset;
2035 		bp->bio_length = MIN(MAXPHYS, sc->sc_mediasize - bp->bio_offset);
2036 		disk->d_sync.ds_offset += bp->bio_length;
2037 		bp->bio_done = g_mirror_sync_done;
2038 		bp->bio_from = disk->d_sync.ds_consumer;
2039 		bp->bio_to = sc->sc_provider;
2040 		bp->bio_caller1 = (void *)(uintptr_t)i;
2041 	}
2042 
2043 	/* Increase the number of disks in SYNCHRONIZING state. */
2044 	sc->sc_sync.ds_ndisks++;
2045 	/* Set the number of in-flight synchronization requests. */
2046 	disk->d_sync.ds_inflight = g_mirror_syncreqs;
2047 
2048 	/*
2049 	 * Fire off first synchronization requests.
2050 	 */
2051 	for (i = 0; i < g_mirror_syncreqs; i++) {
2052 		bp = disk->d_sync.ds_bios[i];
2053 		G_MIRROR_LOGREQ(3, bp, "Sending synchronization request.");
2054 		disk->d_sync.ds_consumer->index++;
2055 		/*
2056 		 * Delay the request if it is colliding with a regular request.
2057 		 */
2058 		if (g_mirror_regular_collision(sc, bp))
2059 			g_mirror_sync_delay(sc, bp);
2060 		else
2061 			g_io_request(bp, disk->d_sync.ds_consumer);
2062 	}
2063 }
2064 
2065 /*
2066  * Stop synchronization process.
2067  * type: 0 - synchronization finished
2068  *       1 - synchronization stopped
2069  */
2070 static void
2071 g_mirror_sync_stop(struct g_mirror_disk *disk, int type)
2072 {
2073 	struct g_mirror_softc *sc;
2074 	struct g_consumer *cp;
2075 
2076 	g_topology_assert_not();
2077 	sc = disk->d_softc;
2078 	sx_assert(&sc->sc_lock, SX_LOCKED);
2079 
2080 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2081 	    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2082 	    g_mirror_disk_state2str(disk->d_state)));
2083 	if (disk->d_sync.ds_consumer == NULL)
2084 		return;
2085 
2086 	if (type == 0) {
2087 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s finished.",
2088 		    sc->sc_name, g_mirror_get_diskname(disk));
2089 	} else /* if (type == 1) */ {
2090 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s stopped.",
2091 		    sc->sc_name, g_mirror_get_diskname(disk));
2092 	}
2093 	g_mirror_regular_release(sc);
2094 	free(disk->d_sync.ds_bios, M_MIRROR);
2095 	disk->d_sync.ds_bios = NULL;
2096 	cp = disk->d_sync.ds_consumer;
2097 	disk->d_sync.ds_consumer = NULL;
2098 	disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2099 	sc->sc_sync.ds_ndisks--;
2100 	sx_xunlock(&sc->sc_lock); /* Avoid recursion on sc_lock. */
2101 	g_topology_lock();
2102 	g_mirror_kill_consumer(sc, cp);
2103 	g_topology_unlock();
2104 	sx_xlock(&sc->sc_lock);
2105 }
2106 
2107 static void
2108 g_mirror_launch_provider(struct g_mirror_softc *sc)
2109 {
2110 	struct g_mirror_disk *disk;
2111 	struct g_provider *pp, *dp;
2112 
2113 	sx_assert(&sc->sc_lock, SX_LOCKED);
2114 
2115 	g_topology_lock();
2116 	pp = g_new_providerf(sc->sc_geom, "mirror/%s", sc->sc_name);
2117 	pp->flags |= G_PF_DIRECT_RECEIVE;
2118 	pp->mediasize = sc->sc_mediasize;
2119 	pp->sectorsize = sc->sc_sectorsize;
2120 	pp->stripesize = 0;
2121 	pp->stripeoffset = 0;
2122 
2123 	/* Splitting of unmapped BIO's could work but isn't implemented now */
2124 	if (sc->sc_balance != G_MIRROR_BALANCE_SPLIT)
2125 		pp->flags |= G_PF_ACCEPT_UNMAPPED;
2126 
2127 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2128 		if (disk->d_consumer && disk->d_consumer->provider) {
2129 			dp = disk->d_consumer->provider;
2130 			if (dp->stripesize > pp->stripesize) {
2131 				pp->stripesize = dp->stripesize;
2132 				pp->stripeoffset = dp->stripeoffset;
2133 			}
2134 			/* A provider underneath us doesn't support unmapped */
2135 			if ((dp->flags & G_PF_ACCEPT_UNMAPPED) == 0) {
2136 				G_MIRROR_DEBUG(0, "Cancelling unmapped "
2137 				    "because of %s.", dp->name);
2138 				pp->flags &= ~G_PF_ACCEPT_UNMAPPED;
2139 			}
2140 		}
2141 	}
2142 	pp->private = sc;
2143 	sc->sc_refcnt++;
2144 	sc->sc_provider = pp;
2145 	g_error_provider(pp, 0);
2146 	g_topology_unlock();
2147 	G_MIRROR_DEBUG(0, "Device %s launched (%u/%u).", pp->name,
2148 	    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE), sc->sc_ndisks);
2149 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2150 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
2151 			g_mirror_sync_start(disk);
2152 	}
2153 }
2154 
2155 static void
2156 g_mirror_destroy_provider(struct g_mirror_softc *sc)
2157 {
2158 	struct g_mirror_disk *disk;
2159 	struct bio *bp;
2160 
2161 	g_topology_assert_not();
2162 	KASSERT(sc->sc_provider != NULL, ("NULL provider (device=%s).",
2163 	    sc->sc_name));
2164 
2165 	g_topology_lock();
2166 	g_error_provider(sc->sc_provider, ENXIO);
2167 	mtx_lock(&sc->sc_queue_mtx);
2168 	while ((bp = bioq_takefirst(&sc->sc_queue)) != NULL) {
2169 		/*
2170 		 * Abort any pending I/O that wasn't generated by us.
2171 		 * Synchronization requests and requests destined for individual
2172 		 * mirror components can be destroyed immediately.
2173 		 */
2174 		if (bp->bio_to == sc->sc_provider &&
2175 		    bp->bio_from->geom != sc->sc_sync.ds_geom) {
2176 			g_io_deliver(bp, ENXIO);
2177 		} else {
2178 			if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0)
2179 				free(bp->bio_data, M_MIRROR);
2180 			g_destroy_bio(bp);
2181 		}
2182 	}
2183 	mtx_unlock(&sc->sc_queue_mtx);
2184 	g_wither_provider(sc->sc_provider, ENXIO);
2185 	sc->sc_provider = NULL;
2186 	G_MIRROR_DEBUG(0, "Device %s: provider destroyed.", sc->sc_name);
2187 	g_topology_unlock();
2188 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2189 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
2190 			g_mirror_sync_stop(disk, 1);
2191 	}
2192 }
2193 
2194 static void
2195 g_mirror_go(void *arg)
2196 {
2197 	struct g_mirror_softc *sc;
2198 
2199 	sc = arg;
2200 	G_MIRROR_DEBUG(0, "Force device %s start due to timeout.", sc->sc_name);
2201 	g_mirror_event_send(sc, 0,
2202 	    G_MIRROR_EVENT_DONTWAIT | G_MIRROR_EVENT_DEVICE);
2203 }
2204 
2205 static u_int
2206 g_mirror_determine_state(struct g_mirror_disk *disk)
2207 {
2208 	struct g_mirror_softc *sc;
2209 	u_int state;
2210 
2211 	sc = disk->d_softc;
2212 	if (sc->sc_syncid == disk->d_sync.ds_syncid) {
2213 		if ((disk->d_flags &
2214 		    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
2215 			/* Disk does not need synchronization. */
2216 			state = G_MIRROR_DISK_STATE_ACTIVE;
2217 		} else {
2218 			if ((sc->sc_flags &
2219 			     G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
2220 			    (disk->d_flags &
2221 			     G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
2222 				/*
2223 				 * We can start synchronization from
2224 				 * the stored offset.
2225 				 */
2226 				state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
2227 			} else {
2228 				state = G_MIRROR_DISK_STATE_STALE;
2229 			}
2230 		}
2231 	} else if (disk->d_sync.ds_syncid < sc->sc_syncid) {
2232 		/*
2233 		 * Reset all synchronization data for this disk,
2234 		 * because if it even was synchronized, it was
2235 		 * synchronized to disks with different syncid.
2236 		 */
2237 		disk->d_flags |= G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2238 		disk->d_sync.ds_offset = 0;
2239 		disk->d_sync.ds_offset_done = 0;
2240 		disk->d_sync.ds_syncid = sc->sc_syncid;
2241 		if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
2242 		    (disk->d_flags & G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
2243 			state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
2244 		} else {
2245 			state = G_MIRROR_DISK_STATE_STALE;
2246 		}
2247 	} else /* if (sc->sc_syncid < disk->d_sync.ds_syncid) */ {
2248 		/*
2249 		 * Not good, NOT GOOD!
2250 		 * It means that mirror was started on stale disks
2251 		 * and more fresh disk just arrive.
2252 		 * If there were writes, mirror is broken, sorry.
2253 		 * I think the best choice here is don't touch
2254 		 * this disk and inform the user loudly.
2255 		 */
2256 		G_MIRROR_DEBUG(0, "Device %s was started before the freshest "
2257 		    "disk (%s) arrives!! It will not be connected to the "
2258 		    "running device.", sc->sc_name,
2259 		    g_mirror_get_diskname(disk));
2260 		g_mirror_destroy_disk(disk);
2261 		state = G_MIRROR_DISK_STATE_NONE;
2262 		/* Return immediately, because disk was destroyed. */
2263 		return (state);
2264 	}
2265 	G_MIRROR_DEBUG(3, "State for %s disk: %s.",
2266 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(state));
2267 	return (state);
2268 }
2269 
2270 /*
2271  * Update device state.
2272  */
2273 static void
2274 g_mirror_update_device(struct g_mirror_softc *sc, bool force)
2275 {
2276 	struct g_mirror_disk *disk;
2277 	u_int state;
2278 
2279 	sx_assert(&sc->sc_lock, SX_XLOCKED);
2280 
2281 	switch (sc->sc_state) {
2282 	case G_MIRROR_DEVICE_STATE_STARTING:
2283 	    {
2284 		struct g_mirror_disk *pdisk, *tdisk;
2285 		u_int dirty, ndisks, genid, syncid;
2286 		bool broken;
2287 
2288 		KASSERT(sc->sc_provider == NULL,
2289 		    ("Non-NULL provider in STARTING state (%s).", sc->sc_name));
2290 		/*
2291 		 * Are we ready? We are, if all disks are connected or
2292 		 * if we have any disks and 'force' is true.
2293 		 */
2294 		ndisks = g_mirror_ndisks(sc, -1);
2295 		if (sc->sc_ndisks == ndisks || (force && ndisks > 0)) {
2296 			;
2297 		} else if (ndisks == 0) {
2298 			/*
2299 			 * Disks went down in starting phase, so destroy
2300 			 * device.
2301 			 */
2302 			callout_drain(&sc->sc_callout);
2303 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2304 			G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p", __LINE__,
2305 			    sc->sc_rootmount);
2306 			root_mount_rel(sc->sc_rootmount);
2307 			sc->sc_rootmount = NULL;
2308 			return;
2309 		} else {
2310 			return;
2311 		}
2312 
2313 		/*
2314 		 * Activate all disks with the biggest syncid.
2315 		 */
2316 		if (force) {
2317 			/*
2318 			 * If 'force' is true, we have been called due to
2319 			 * timeout, so don't bother canceling timeout.
2320 			 */
2321 			ndisks = 0;
2322 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2323 				if ((disk->d_flags &
2324 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
2325 					ndisks++;
2326 				}
2327 			}
2328 			if (ndisks == 0) {
2329 				/* No valid disks found, destroy device. */
2330 				sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2331 				G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p",
2332 				    __LINE__, sc->sc_rootmount);
2333 				root_mount_rel(sc->sc_rootmount);
2334 				sc->sc_rootmount = NULL;
2335 				return;
2336 			}
2337 		} else {
2338 			/* Cancel timeout. */
2339 			callout_drain(&sc->sc_callout);
2340 		}
2341 
2342 		/*
2343 		 * Find the biggest genid.
2344 		 */
2345 		genid = 0;
2346 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2347 			if (disk->d_genid > genid)
2348 				genid = disk->d_genid;
2349 		}
2350 		sc->sc_genid = genid;
2351 		/*
2352 		 * Remove all disks without the biggest genid.
2353 		 */
2354 		broken = false;
2355 		LIST_FOREACH_SAFE(disk, &sc->sc_disks, d_next, tdisk) {
2356 			if (disk->d_genid < genid) {
2357 				G_MIRROR_DEBUG(0,
2358 				    "Component %s (device %s) broken, skipping.",
2359 				    g_mirror_get_diskname(disk), sc->sc_name);
2360 				g_mirror_destroy_disk(disk);
2361 				/*
2362 				 * Bump the syncid in case we discover a healthy
2363 				 * replacement disk after starting the mirror.
2364 				 */
2365 				broken = true;
2366 			}
2367 		}
2368 
2369 		/*
2370 		 * Find the biggest syncid.
2371 		 */
2372 		syncid = 0;
2373 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2374 			if (disk->d_sync.ds_syncid > syncid)
2375 				syncid = disk->d_sync.ds_syncid;
2376 		}
2377 
2378 		/*
2379 		 * Here we need to look for dirty disks and if all disks
2380 		 * with the biggest syncid are dirty, we have to choose
2381 		 * one with the biggest priority and rebuild the rest.
2382 		 */
2383 		/*
2384 		 * Find the number of dirty disks with the biggest syncid.
2385 		 * Find the number of disks with the biggest syncid.
2386 		 * While here, find a disk with the biggest priority.
2387 		 */
2388 		dirty = ndisks = 0;
2389 		pdisk = NULL;
2390 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2391 			if (disk->d_sync.ds_syncid != syncid)
2392 				continue;
2393 			if ((disk->d_flags &
2394 			    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2395 				continue;
2396 			}
2397 			ndisks++;
2398 			if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
2399 				dirty++;
2400 				if (pdisk == NULL ||
2401 				    pdisk->d_priority < disk->d_priority) {
2402 					pdisk = disk;
2403 				}
2404 			}
2405 		}
2406 		if (dirty == 0) {
2407 			/* No dirty disks at all, great. */
2408 		} else if (dirty == ndisks) {
2409 			/*
2410 			 * Force synchronization for all dirty disks except one
2411 			 * with the biggest priority.
2412 			 */
2413 			KASSERT(pdisk != NULL, ("pdisk == NULL"));
2414 			G_MIRROR_DEBUG(1, "Using disk %s (device %s) as a "
2415 			    "master disk for synchronization.",
2416 			    g_mirror_get_diskname(pdisk), sc->sc_name);
2417 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2418 				if (disk->d_sync.ds_syncid != syncid)
2419 					continue;
2420 				if ((disk->d_flags &
2421 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2422 					continue;
2423 				}
2424 				KASSERT((disk->d_flags &
2425 				    G_MIRROR_DISK_FLAG_DIRTY) != 0,
2426 				    ("Disk %s isn't marked as dirty.",
2427 				    g_mirror_get_diskname(disk)));
2428 				/* Skip the disk with the biggest priority. */
2429 				if (disk == pdisk)
2430 					continue;
2431 				disk->d_sync.ds_syncid = 0;
2432 			}
2433 		} else if (dirty < ndisks) {
2434 			/*
2435 			 * Force synchronization for all dirty disks.
2436 			 * We have some non-dirty disks.
2437 			 */
2438 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2439 				if (disk->d_sync.ds_syncid != syncid)
2440 					continue;
2441 				if ((disk->d_flags &
2442 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2443 					continue;
2444 				}
2445 				if ((disk->d_flags &
2446 				    G_MIRROR_DISK_FLAG_DIRTY) == 0) {
2447 					continue;
2448 				}
2449 				disk->d_sync.ds_syncid = 0;
2450 			}
2451 		}
2452 
2453 		/* Reset hint. */
2454 		sc->sc_hint = NULL;
2455 		sc->sc_syncid = syncid;
2456 		if (force || broken) {
2457 			/* Remember to bump syncid on first write. */
2458 			sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2459 		}
2460 		state = G_MIRROR_DEVICE_STATE_RUNNING;
2461 		G_MIRROR_DEBUG(1, "Device %s state changed from %s to %s.",
2462 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state),
2463 		    g_mirror_device_state2str(state));
2464 		sc->sc_state = state;
2465 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2466 			state = g_mirror_determine_state(disk);
2467 			g_mirror_event_send(disk, state,
2468 			    G_MIRROR_EVENT_DONTWAIT);
2469 			if (state == G_MIRROR_DISK_STATE_STALE)
2470 				sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2471 		}
2472 		break;
2473 	    }
2474 	case G_MIRROR_DEVICE_STATE_RUNNING:
2475 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 0 &&
2476 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2477 			/*
2478 			 * No active disks or no disks at all,
2479 			 * so destroy device.
2480 			 */
2481 			if (sc->sc_provider != NULL)
2482 				g_mirror_destroy_provider(sc);
2483 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2484 			break;
2485 		} else if (g_mirror_ndisks(sc,
2486 		    G_MIRROR_DISK_STATE_ACTIVE) > 0 &&
2487 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2488 			/*
2489 			 * We have active disks, launch provider if it doesn't
2490 			 * exist.
2491 			 */
2492 			if (sc->sc_provider == NULL)
2493 				g_mirror_launch_provider(sc);
2494 			if (sc->sc_rootmount != NULL) {
2495 				G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p",
2496 				    __LINE__, sc->sc_rootmount);
2497 				root_mount_rel(sc->sc_rootmount);
2498 				sc->sc_rootmount = NULL;
2499 			}
2500 		}
2501 		/*
2502 		 * Genid should be bumped immediately, so do it here.
2503 		 */
2504 		if ((sc->sc_bump_id & G_MIRROR_BUMP_GENID) != 0) {
2505 			sc->sc_bump_id &= ~G_MIRROR_BUMP_GENID;
2506 			g_mirror_bump_genid(sc);
2507 		}
2508 		break;
2509 	default:
2510 		KASSERT(1 == 0, ("Wrong device state (%s, %s).",
2511 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state)));
2512 		break;
2513 	}
2514 }
2515 
2516 /*
2517  * Update disk state and device state if needed.
2518  */
2519 #define	DISK_STATE_CHANGED()	G_MIRROR_DEBUG(1,			\
2520 	"Disk %s state changed from %s to %s (device %s).",		\
2521 	g_mirror_get_diskname(disk),					\
2522 	g_mirror_disk_state2str(disk->d_state),				\
2523 	g_mirror_disk_state2str(state), sc->sc_name)
2524 static int
2525 g_mirror_update_disk(struct g_mirror_disk *disk, u_int state)
2526 {
2527 	struct g_mirror_softc *sc;
2528 
2529 	sc = disk->d_softc;
2530 	sx_assert(&sc->sc_lock, SX_XLOCKED);
2531 
2532 again:
2533 	G_MIRROR_DEBUG(3, "Changing disk %s state from %s to %s.",
2534 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(disk->d_state),
2535 	    g_mirror_disk_state2str(state));
2536 	switch (state) {
2537 	case G_MIRROR_DISK_STATE_NEW:
2538 		/*
2539 		 * Possible scenarios:
2540 		 * 1. New disk arrive.
2541 		 */
2542 		/* Previous state should be NONE. */
2543 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NONE,
2544 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2545 		    g_mirror_disk_state2str(disk->d_state)));
2546 		DISK_STATE_CHANGED();
2547 
2548 		disk->d_state = state;
2549 		if (LIST_EMPTY(&sc->sc_disks))
2550 			LIST_INSERT_HEAD(&sc->sc_disks, disk, d_next);
2551 		else {
2552 			struct g_mirror_disk *dp;
2553 
2554 			LIST_FOREACH(dp, &sc->sc_disks, d_next) {
2555 				if (disk->d_priority >= dp->d_priority) {
2556 					LIST_INSERT_BEFORE(dp, disk, d_next);
2557 					dp = NULL;
2558 					break;
2559 				}
2560 				if (LIST_NEXT(dp, d_next) == NULL)
2561 					break;
2562 			}
2563 			if (dp != NULL)
2564 				LIST_INSERT_AFTER(dp, disk, d_next);
2565 		}
2566 		G_MIRROR_DEBUG(1, "Device %s: provider %s detected.",
2567 		    sc->sc_name, g_mirror_get_diskname(disk));
2568 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
2569 			break;
2570 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2571 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2572 		    g_mirror_device_state2str(sc->sc_state),
2573 		    g_mirror_get_diskname(disk),
2574 		    g_mirror_disk_state2str(disk->d_state)));
2575 		state = g_mirror_determine_state(disk);
2576 		if (state != G_MIRROR_DISK_STATE_NONE)
2577 			goto again;
2578 		break;
2579 	case G_MIRROR_DISK_STATE_ACTIVE:
2580 		/*
2581 		 * Possible scenarios:
2582 		 * 1. New disk does not need synchronization.
2583 		 * 2. Synchronization process finished successfully.
2584 		 */
2585 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2586 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2587 		    g_mirror_device_state2str(sc->sc_state),
2588 		    g_mirror_get_diskname(disk),
2589 		    g_mirror_disk_state2str(disk->d_state)));
2590 		/* Previous state should be NEW or SYNCHRONIZING. */
2591 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW ||
2592 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2593 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2594 		    g_mirror_disk_state2str(disk->d_state)));
2595 		DISK_STATE_CHANGED();
2596 
2597 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2598 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2599 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_FORCE_SYNC;
2600 			g_mirror_sync_stop(disk, 0);
2601 		}
2602 		disk->d_state = state;
2603 		disk->d_sync.ds_offset = 0;
2604 		disk->d_sync.ds_offset_done = 0;
2605 		g_mirror_update_idle(sc, disk);
2606 		g_mirror_update_metadata(disk);
2607 		G_MIRROR_DEBUG(1, "Device %s: provider %s activated.",
2608 		    sc->sc_name, g_mirror_get_diskname(disk));
2609 		break;
2610 	case G_MIRROR_DISK_STATE_STALE:
2611 		/*
2612 		 * Possible scenarios:
2613 		 * 1. Stale disk was connected.
2614 		 */
2615 		/* Previous state should be NEW. */
2616 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2617 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2618 		    g_mirror_disk_state2str(disk->d_state)));
2619 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2620 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2621 		    g_mirror_device_state2str(sc->sc_state),
2622 		    g_mirror_get_diskname(disk),
2623 		    g_mirror_disk_state2str(disk->d_state)));
2624 		/*
2625 		 * STALE state is only possible if device is marked
2626 		 * NOAUTOSYNC.
2627 		 */
2628 		KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) != 0,
2629 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2630 		    g_mirror_device_state2str(sc->sc_state),
2631 		    g_mirror_get_diskname(disk),
2632 		    g_mirror_disk_state2str(disk->d_state)));
2633 		DISK_STATE_CHANGED();
2634 
2635 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2636 		disk->d_state = state;
2637 		g_mirror_update_metadata(disk);
2638 		G_MIRROR_DEBUG(0, "Device %s: provider %s is stale.",
2639 		    sc->sc_name, g_mirror_get_diskname(disk));
2640 		break;
2641 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
2642 		/*
2643 		 * Possible scenarios:
2644 		 * 1. Disk which needs synchronization was connected.
2645 		 */
2646 		/* Previous state should be NEW. */
2647 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2648 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2649 		    g_mirror_disk_state2str(disk->d_state)));
2650 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2651 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2652 		    g_mirror_device_state2str(sc->sc_state),
2653 		    g_mirror_get_diskname(disk),
2654 		    g_mirror_disk_state2str(disk->d_state)));
2655 		DISK_STATE_CHANGED();
2656 
2657 		if (disk->d_state == G_MIRROR_DISK_STATE_NEW)
2658 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2659 		disk->d_state = state;
2660 		if (sc->sc_provider != NULL) {
2661 			g_mirror_sync_start(disk);
2662 			g_mirror_update_metadata(disk);
2663 		}
2664 		break;
2665 	case G_MIRROR_DISK_STATE_DISCONNECTED:
2666 		/*
2667 		 * Possible scenarios:
2668 		 * 1. Device wasn't running yet, but disk disappear.
2669 		 * 2. Disk was active and disapppear.
2670 		 * 3. Disk disappear during synchronization process.
2671 		 */
2672 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING) {
2673 			/*
2674 			 * Previous state should be ACTIVE, STALE or
2675 			 * SYNCHRONIZING.
2676 			 */
2677 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
2678 			    disk->d_state == G_MIRROR_DISK_STATE_STALE ||
2679 			    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2680 			    ("Wrong disk state (%s, %s).",
2681 			    g_mirror_get_diskname(disk),
2682 			    g_mirror_disk_state2str(disk->d_state)));
2683 		} else if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING) {
2684 			/* Previous state should be NEW. */
2685 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2686 			    ("Wrong disk state (%s, %s).",
2687 			    g_mirror_get_diskname(disk),
2688 			    g_mirror_disk_state2str(disk->d_state)));
2689 			/*
2690 			 * Reset bumping syncid if disk disappeared in STARTING
2691 			 * state.
2692 			 */
2693 			if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0)
2694 				sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
2695 #ifdef	INVARIANTS
2696 		} else {
2697 			KASSERT(1 == 0, ("Wrong device state (%s, %s, %s, %s).",
2698 			    sc->sc_name,
2699 			    g_mirror_device_state2str(sc->sc_state),
2700 			    g_mirror_get_diskname(disk),
2701 			    g_mirror_disk_state2str(disk->d_state)));
2702 #endif
2703 		}
2704 		DISK_STATE_CHANGED();
2705 		G_MIRROR_DEBUG(0, "Device %s: provider %s disconnected.",
2706 		    sc->sc_name, g_mirror_get_diskname(disk));
2707 
2708 		g_mirror_destroy_disk(disk);
2709 		break;
2710 	case G_MIRROR_DISK_STATE_DESTROY:
2711 	    {
2712 		int error;
2713 
2714 		error = g_mirror_clear_metadata(disk);
2715 		if (error != 0) {
2716 			G_MIRROR_DEBUG(0,
2717 			    "Device %s: failed to clear metadata on %s: %d.",
2718 			    sc->sc_name, g_mirror_get_diskname(disk), error);
2719 			break;
2720 		}
2721 		DISK_STATE_CHANGED();
2722 		G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.",
2723 		    sc->sc_name, g_mirror_get_diskname(disk));
2724 
2725 		g_mirror_destroy_disk(disk);
2726 		sc->sc_ndisks--;
2727 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2728 			g_mirror_update_metadata(disk);
2729 		}
2730 		break;
2731 	    }
2732 	default:
2733 		KASSERT(1 == 0, ("Unknown state (%u).", state));
2734 		break;
2735 	}
2736 	return (0);
2737 }
2738 #undef	DISK_STATE_CHANGED
2739 
2740 int
2741 g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md)
2742 {
2743 	struct g_provider *pp;
2744 	u_char *buf;
2745 	int error;
2746 
2747 	g_topology_assert();
2748 
2749 	error = g_access(cp, 1, 0, 0);
2750 	if (error != 0)
2751 		return (error);
2752 	pp = cp->provider;
2753 	g_topology_unlock();
2754 	/* Metadata are stored on last sector. */
2755 	buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
2756 	    &error);
2757 	g_topology_lock();
2758 	g_access(cp, -1, 0, 0);
2759 	if (buf == NULL) {
2760 		G_MIRROR_DEBUG(1, "Cannot read metadata from %s (error=%d).",
2761 		    cp->provider->name, error);
2762 		return (error);
2763 	}
2764 
2765 	/* Decode metadata. */
2766 	error = mirror_metadata_decode(buf, md);
2767 	g_free(buf);
2768 	if (strcmp(md->md_magic, G_MIRROR_MAGIC) != 0)
2769 		return (EINVAL);
2770 	if (md->md_version > G_MIRROR_VERSION) {
2771 		G_MIRROR_DEBUG(0,
2772 		    "Kernel module is too old to handle metadata from %s.",
2773 		    cp->provider->name);
2774 		return (EINVAL);
2775 	}
2776 	if (error != 0) {
2777 		G_MIRROR_DEBUG(1, "MD5 metadata hash mismatch for provider %s.",
2778 		    cp->provider->name);
2779 		return (error);
2780 	}
2781 
2782 	return (0);
2783 }
2784 
2785 static int
2786 g_mirror_check_metadata(struct g_mirror_softc *sc, struct g_provider *pp,
2787     struct g_mirror_metadata *md)
2788 {
2789 
2790 	if (g_mirror_id2disk(sc, md->md_did) != NULL) {
2791 		G_MIRROR_DEBUG(1, "Disk %s (id=%u) already exists, skipping.",
2792 		    pp->name, md->md_did);
2793 		return (EEXIST);
2794 	}
2795 	if (md->md_all != sc->sc_ndisks) {
2796 		G_MIRROR_DEBUG(1,
2797 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2798 		    "md_all", pp->name, sc->sc_name);
2799 		return (EINVAL);
2800 	}
2801 	if (md->md_slice != sc->sc_slice) {
2802 		G_MIRROR_DEBUG(1,
2803 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2804 		    "md_slice", pp->name, sc->sc_name);
2805 		return (EINVAL);
2806 	}
2807 	if (md->md_balance != sc->sc_balance) {
2808 		G_MIRROR_DEBUG(1,
2809 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2810 		    "md_balance", pp->name, sc->sc_name);
2811 		return (EINVAL);
2812 	}
2813 #if 0
2814 	if (md->md_mediasize != sc->sc_mediasize) {
2815 		G_MIRROR_DEBUG(1,
2816 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2817 		    "md_mediasize", pp->name, sc->sc_name);
2818 		return (EINVAL);
2819 	}
2820 #endif
2821 	if (sc->sc_mediasize > pp->mediasize) {
2822 		G_MIRROR_DEBUG(1,
2823 		    "Invalid size of disk %s (device %s), skipping.", pp->name,
2824 		    sc->sc_name);
2825 		return (EINVAL);
2826 	}
2827 	if (md->md_sectorsize != sc->sc_sectorsize) {
2828 		G_MIRROR_DEBUG(1,
2829 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2830 		    "md_sectorsize", pp->name, sc->sc_name);
2831 		return (EINVAL);
2832 	}
2833 	if ((sc->sc_sectorsize % pp->sectorsize) != 0) {
2834 		G_MIRROR_DEBUG(1,
2835 		    "Invalid sector size of disk %s (device %s), skipping.",
2836 		    pp->name, sc->sc_name);
2837 		return (EINVAL);
2838 	}
2839 	if ((md->md_mflags & ~G_MIRROR_DEVICE_FLAG_MASK) != 0) {
2840 		G_MIRROR_DEBUG(1,
2841 		    "Invalid device flags on disk %s (device %s), skipping.",
2842 		    pp->name, sc->sc_name);
2843 		return (EINVAL);
2844 	}
2845 	if ((md->md_dflags & ~G_MIRROR_DISK_FLAG_MASK) != 0) {
2846 		G_MIRROR_DEBUG(1,
2847 		    "Invalid disk flags on disk %s (device %s), skipping.",
2848 		    pp->name, sc->sc_name);
2849 		return (EINVAL);
2850 	}
2851 	return (0);
2852 }
2853 
2854 int
2855 g_mirror_add_disk(struct g_mirror_softc *sc, struct g_provider *pp,
2856     struct g_mirror_metadata *md)
2857 {
2858 	struct g_mirror_disk *disk;
2859 	int error;
2860 
2861 	g_topology_assert_not();
2862 	G_MIRROR_DEBUG(2, "Adding disk %s.", pp->name);
2863 
2864 	error = g_mirror_check_metadata(sc, pp, md);
2865 	if (error != 0)
2866 		return (error);
2867 	if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING &&
2868 	    md->md_genid < sc->sc_genid) {
2869 		G_MIRROR_DEBUG(0, "Component %s (device %s) broken, skipping.",
2870 		    pp->name, sc->sc_name);
2871 		return (EINVAL);
2872 	}
2873 	disk = g_mirror_init_disk(sc, pp, md, &error);
2874 	if (disk == NULL)
2875 		return (error);
2876 	error = g_mirror_event_send(disk, G_MIRROR_DISK_STATE_NEW,
2877 	    G_MIRROR_EVENT_WAIT);
2878 	if (error != 0)
2879 		return (error);
2880 	if (md->md_version < G_MIRROR_VERSION) {
2881 		G_MIRROR_DEBUG(0, "Upgrading metadata on %s (v%d->v%d).",
2882 		    pp->name, md->md_version, G_MIRROR_VERSION);
2883 		g_mirror_update_metadata(disk);
2884 	}
2885 	return (0);
2886 }
2887 
2888 static void
2889 g_mirror_destroy_delayed(void *arg, int flag)
2890 {
2891 	struct g_mirror_softc *sc;
2892 	int error;
2893 
2894 	if (flag == EV_CANCEL) {
2895 		G_MIRROR_DEBUG(1, "Destroying canceled.");
2896 		return;
2897 	}
2898 	sc = arg;
2899 	g_topology_unlock();
2900 	sx_xlock(&sc->sc_lock);
2901 	KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) == 0,
2902 	    ("DESTROY flag set on %s.", sc->sc_name));
2903 	KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROYING) != 0,
2904 	    ("DESTROYING flag not set on %s.", sc->sc_name));
2905 	G_MIRROR_DEBUG(1, "Destroying %s (delayed).", sc->sc_name);
2906 	error = g_mirror_destroy(sc, G_MIRROR_DESTROY_SOFT);
2907 	if (error != 0) {
2908 		G_MIRROR_DEBUG(0, "Cannot destroy %s (error=%d).",
2909 		    sc->sc_name, error);
2910 		sx_xunlock(&sc->sc_lock);
2911 	}
2912 	g_topology_lock();
2913 }
2914 
2915 static int
2916 g_mirror_access(struct g_provider *pp, int acr, int acw, int ace)
2917 {
2918 	struct g_mirror_softc *sc;
2919 	int error = 0;
2920 
2921 	g_topology_assert();
2922 	G_MIRROR_DEBUG(2, "Access request for %s: r%dw%de%d.", pp->name, acr,
2923 	    acw, ace);
2924 
2925 	sc = pp->private;
2926 	KASSERT(sc != NULL, ("NULL softc (provider=%s).", pp->name));
2927 
2928 	g_topology_unlock();
2929 	sx_xlock(&sc->sc_lock);
2930 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0 ||
2931 	    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROYING) != 0 ||
2932 	    LIST_EMPTY(&sc->sc_disks)) {
2933 		if (acr > 0 || acw > 0 || ace > 0)
2934 			error = ENXIO;
2935 		goto end;
2936 	}
2937 	sc->sc_provider_open += acr + acw + ace;
2938 	if (pp->acw + acw == 0)
2939 		g_mirror_idle(sc, 0);
2940 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROYING) != 0 &&
2941 	    sc->sc_provider_open == 0)
2942 		g_post_event(g_mirror_destroy_delayed, sc, M_WAITOK, sc, NULL);
2943 end:
2944 	sx_xunlock(&sc->sc_lock);
2945 	g_topology_lock();
2946 	return (error);
2947 }
2948 
2949 struct g_geom *
2950 g_mirror_create(struct g_class *mp, const struct g_mirror_metadata *md,
2951     u_int type)
2952 {
2953 	struct g_mirror_softc *sc;
2954 	struct g_geom *gp;
2955 	int error, timeout;
2956 
2957 	g_topology_assert();
2958 	G_MIRROR_DEBUG(1, "Creating device %s (id=%u).", md->md_name,
2959 	    md->md_mid);
2960 
2961 	/* One disk is minimum. */
2962 	if (md->md_all < 1)
2963 		return (NULL);
2964 	/*
2965 	 * Action geom.
2966 	 */
2967 	gp = g_new_geomf(mp, "%s", md->md_name);
2968 	sc = malloc(sizeof(*sc), M_MIRROR, M_WAITOK | M_ZERO);
2969 	gp->start = g_mirror_start;
2970 	gp->orphan = g_mirror_orphan;
2971 	gp->access = g_mirror_access;
2972 	gp->dumpconf = g_mirror_dumpconf;
2973 
2974 	sc->sc_type = type;
2975 	sc->sc_id = md->md_mid;
2976 	sc->sc_slice = md->md_slice;
2977 	sc->sc_balance = md->md_balance;
2978 	sc->sc_mediasize = md->md_mediasize;
2979 	sc->sc_sectorsize = md->md_sectorsize;
2980 	sc->sc_ndisks = md->md_all;
2981 	sc->sc_flags = md->md_mflags;
2982 	sc->sc_bump_id = 0;
2983 	sc->sc_idle = 1;
2984 	sc->sc_last_write = time_uptime;
2985 	sc->sc_writes = 0;
2986 	sc->sc_refcnt = 1;
2987 	sx_init(&sc->sc_lock, "gmirror:lock");
2988 	bioq_init(&sc->sc_queue);
2989 	mtx_init(&sc->sc_queue_mtx, "gmirror:queue", NULL, MTX_DEF);
2990 	bioq_init(&sc->sc_regular_delayed);
2991 	bioq_init(&sc->sc_inflight);
2992 	bioq_init(&sc->sc_sync_delayed);
2993 	LIST_INIT(&sc->sc_disks);
2994 	TAILQ_INIT(&sc->sc_events);
2995 	mtx_init(&sc->sc_events_mtx, "gmirror:events", NULL, MTX_DEF);
2996 	callout_init(&sc->sc_callout, 1);
2997 	mtx_init(&sc->sc_done_mtx, "gmirror:done", NULL, MTX_DEF);
2998 	sc->sc_state = G_MIRROR_DEVICE_STATE_STARTING;
2999 	gp->softc = sc;
3000 	sc->sc_geom = gp;
3001 	sc->sc_provider = NULL;
3002 	sc->sc_provider_open = 0;
3003 	/*
3004 	 * Synchronization geom.
3005 	 */
3006 	gp = g_new_geomf(mp, "%s.sync", md->md_name);
3007 	gp->softc = sc;
3008 	gp->orphan = g_mirror_orphan;
3009 	sc->sc_sync.ds_geom = gp;
3010 	sc->sc_sync.ds_ndisks = 0;
3011 	error = kproc_create(g_mirror_worker, sc, &sc->sc_worker, 0, 0,
3012 	    "g_mirror %s", md->md_name);
3013 	if (error != 0) {
3014 		G_MIRROR_DEBUG(1, "Cannot create kernel thread for %s.",
3015 		    sc->sc_name);
3016 		g_destroy_geom(sc->sc_sync.ds_geom);
3017 		g_destroy_geom(sc->sc_geom);
3018 		g_mirror_free_device(sc);
3019 		return (NULL);
3020 	}
3021 
3022 	G_MIRROR_DEBUG(1, "Device %s created (%u components, id=%u).",
3023 	    sc->sc_name, sc->sc_ndisks, sc->sc_id);
3024 
3025 	sc->sc_rootmount = root_mount_hold("GMIRROR");
3026 	G_MIRROR_DEBUG(1, "root_mount_hold %p", sc->sc_rootmount);
3027 	/*
3028 	 * Run timeout.
3029 	 */
3030 	timeout = g_mirror_timeout * hz;
3031 	callout_reset(&sc->sc_callout, timeout, g_mirror_go, sc);
3032 	return (sc->sc_geom);
3033 }
3034 
3035 int
3036 g_mirror_destroy(struct g_mirror_softc *sc, int how)
3037 {
3038 	struct g_mirror_disk *disk;
3039 
3040 	g_topology_assert_not();
3041 	sx_assert(&sc->sc_lock, SX_XLOCKED);
3042 
3043 	if (sc->sc_provider_open != 0 || SCHEDULER_STOPPED()) {
3044 		switch (how) {
3045 		case G_MIRROR_DESTROY_SOFT:
3046 			G_MIRROR_DEBUG(1,
3047 			    "Device %s is still open (%d).", sc->sc_name,
3048 			    sc->sc_provider_open);
3049 			return (EBUSY);
3050 		case G_MIRROR_DESTROY_DELAYED:
3051 			G_MIRROR_DEBUG(1,
3052 			    "Device %s will be destroyed on last close.",
3053 			    sc->sc_name);
3054 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
3055 				if (disk->d_state ==
3056 				    G_MIRROR_DISK_STATE_SYNCHRONIZING) {
3057 					g_mirror_sync_stop(disk, 1);
3058 				}
3059 			}
3060 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROYING;
3061 			return (EBUSY);
3062 		case G_MIRROR_DESTROY_HARD:
3063 			G_MIRROR_DEBUG(1, "Device %s is still open, so it "
3064 			    "can't be definitely removed.", sc->sc_name);
3065 		}
3066 	}
3067 
3068 	g_topology_lock();
3069 	if (sc->sc_geom->softc == NULL) {
3070 		g_topology_unlock();
3071 		return (0);
3072 	}
3073 	sc->sc_geom->softc = NULL;
3074 	sc->sc_sync.ds_geom->softc = NULL;
3075 	g_topology_unlock();
3076 
3077 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
3078 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_WAIT;
3079 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
3080 	sx_xunlock(&sc->sc_lock);
3081 	mtx_lock(&sc->sc_queue_mtx);
3082 	wakeup(sc);
3083 	mtx_unlock(&sc->sc_queue_mtx);
3084 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, &sc->sc_worker);
3085 	while (sc->sc_worker != NULL)
3086 		tsleep(&sc->sc_worker, PRIBIO, "m:destroy", hz / 5);
3087 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, &sc->sc_worker);
3088 	sx_xlock(&sc->sc_lock);
3089 	g_mirror_destroy_device(sc);
3090 	return (0);
3091 }
3092 
3093 static void
3094 g_mirror_taste_orphan(struct g_consumer *cp)
3095 {
3096 
3097 	KASSERT(1 == 0, ("%s called while tasting %s.", __func__,
3098 	    cp->provider->name));
3099 }
3100 
3101 static struct g_geom *
3102 g_mirror_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
3103 {
3104 	struct g_mirror_metadata md;
3105 	struct g_mirror_softc *sc;
3106 	struct g_consumer *cp;
3107 	struct g_geom *gp;
3108 	int error;
3109 
3110 	g_topology_assert();
3111 	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
3112 	G_MIRROR_DEBUG(2, "Tasting %s.", pp->name);
3113 
3114 	gp = g_new_geomf(mp, "mirror:taste");
3115 	/*
3116 	 * This orphan function should be never called.
3117 	 */
3118 	gp->orphan = g_mirror_taste_orphan;
3119 	cp = g_new_consumer(gp);
3120 	g_attach(cp, pp);
3121 	error = g_mirror_read_metadata(cp, &md);
3122 	g_detach(cp);
3123 	g_destroy_consumer(cp);
3124 	g_destroy_geom(gp);
3125 	if (error != 0)
3126 		return (NULL);
3127 	gp = NULL;
3128 
3129 	if (md.md_provider[0] != '\0' &&
3130 	    !g_compare_names(md.md_provider, pp->name))
3131 		return (NULL);
3132 	if (md.md_provsize != 0 && md.md_provsize != pp->mediasize)
3133 		return (NULL);
3134 	if ((md.md_dflags & G_MIRROR_DISK_FLAG_INACTIVE) != 0) {
3135 		G_MIRROR_DEBUG(0,
3136 		    "Device %s: provider %s marked as inactive, skipping.",
3137 		    md.md_name, pp->name);
3138 		return (NULL);
3139 	}
3140 	if (g_mirror_debug >= 2)
3141 		mirror_metadata_dump(&md);
3142 
3143 	/*
3144 	 * Let's check if device already exists.
3145 	 */
3146 	sc = NULL;
3147 	LIST_FOREACH(gp, &mp->geom, geom) {
3148 		sc = gp->softc;
3149 		if (sc == NULL)
3150 			continue;
3151 		if (sc->sc_type != G_MIRROR_TYPE_AUTOMATIC)
3152 			continue;
3153 		if (sc->sc_sync.ds_geom == gp)
3154 			continue;
3155 		if (strcmp(md.md_name, sc->sc_name) != 0)
3156 			continue;
3157 		if (md.md_mid != sc->sc_id) {
3158 			G_MIRROR_DEBUG(0, "Device %s already configured.",
3159 			    sc->sc_name);
3160 			return (NULL);
3161 		}
3162 		break;
3163 	}
3164 	if (gp == NULL) {
3165 		gp = g_mirror_create(mp, &md, G_MIRROR_TYPE_AUTOMATIC);
3166 		if (gp == NULL) {
3167 			G_MIRROR_DEBUG(0, "Cannot create device %s.",
3168 			    md.md_name);
3169 			return (NULL);
3170 		}
3171 		sc = gp->softc;
3172 	}
3173 	G_MIRROR_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
3174 	g_topology_unlock();
3175 	sx_xlock(&sc->sc_lock);
3176 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_TASTING;
3177 	error = g_mirror_add_disk(sc, pp, &md);
3178 	if (error != 0) {
3179 		G_MIRROR_DEBUG(0, "Cannot add disk %s to %s (error=%d).",
3180 		    pp->name, gp->name, error);
3181 		if (LIST_EMPTY(&sc->sc_disks)) {
3182 			g_cancel_event(sc);
3183 			g_mirror_destroy(sc, G_MIRROR_DESTROY_HARD);
3184 			g_topology_lock();
3185 			return (NULL);
3186 		}
3187 		gp = NULL;
3188 	}
3189 	sc->sc_flags &= ~G_MIRROR_DEVICE_FLAG_TASTING;
3190 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
3191 		g_mirror_destroy(sc, G_MIRROR_DESTROY_HARD);
3192 		g_topology_lock();
3193 		return (NULL);
3194 	}
3195 	sx_xunlock(&sc->sc_lock);
3196 	g_topology_lock();
3197 	return (gp);
3198 }
3199 
3200 static void
3201 g_mirror_resize(struct g_consumer *cp)
3202 {
3203 	struct g_mirror_disk *disk;
3204 
3205 	g_topology_assert();
3206 	g_trace(G_T_TOPOLOGY, "%s(%s)", __func__, cp->provider->name);
3207 
3208 	disk = cp->private;
3209 	if (disk == NULL)
3210 		return;
3211 	g_topology_unlock();
3212 	g_mirror_update_metadata(disk);
3213 	g_topology_lock();
3214 }
3215 
3216 static int
3217 g_mirror_destroy_geom(struct gctl_req *req __unused,
3218     struct g_class *mp __unused, struct g_geom *gp)
3219 {
3220 	struct g_mirror_softc *sc;
3221 	int error;
3222 
3223 	g_topology_unlock();
3224 	sc = gp->softc;
3225 	sx_xlock(&sc->sc_lock);
3226 	g_cancel_event(sc);
3227 	error = g_mirror_destroy(gp->softc, G_MIRROR_DESTROY_SOFT);
3228 	if (error != 0)
3229 		sx_xunlock(&sc->sc_lock);
3230 	g_topology_lock();
3231 	return (error);
3232 }
3233 
3234 static void
3235 g_mirror_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
3236     struct g_consumer *cp, struct g_provider *pp)
3237 {
3238 	struct g_mirror_softc *sc;
3239 
3240 	g_topology_assert();
3241 
3242 	sc = gp->softc;
3243 	if (sc == NULL)
3244 		return;
3245 	/* Skip synchronization geom. */
3246 	if (gp == sc->sc_sync.ds_geom)
3247 		return;
3248 	if (pp != NULL) {
3249 		/* Nothing here. */
3250 	} else if (cp != NULL) {
3251 		struct g_mirror_disk *disk;
3252 
3253 		disk = cp->private;
3254 		if (disk == NULL)
3255 			return;
3256 		g_topology_unlock();
3257 		sx_xlock(&sc->sc_lock);
3258 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)disk->d_id);
3259 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
3260 			sbuf_printf(sb, "%s<Synchronized>", indent);
3261 			if (disk->d_sync.ds_offset == 0)
3262 				sbuf_printf(sb, "0%%");
3263 			else {
3264 				sbuf_printf(sb, "%u%%",
3265 				    (u_int)((disk->d_sync.ds_offset * 100) /
3266 				    sc->sc_provider->mediasize));
3267 			}
3268 			sbuf_printf(sb, "</Synchronized>\n");
3269 			if (disk->d_sync.ds_offset > 0) {
3270 				sbuf_printf(sb, "%s<BytesSynced>%jd"
3271 				    "</BytesSynced>\n", indent,
3272 				    (intmax_t)disk->d_sync.ds_offset);
3273 			}
3274 		}
3275 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent,
3276 		    disk->d_sync.ds_syncid);
3277 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent,
3278 		    disk->d_genid);
3279 		sbuf_printf(sb, "%s<Flags>", indent);
3280 		if (disk->d_flags == 0)
3281 			sbuf_printf(sb, "NONE");
3282 		else {
3283 			int first = 1;
3284 
3285 #define	ADD_FLAG(flag, name)	do {					\
3286 	if ((disk->d_flags & (flag)) != 0) {				\
3287 		if (!first)						\
3288 			sbuf_printf(sb, ", ");				\
3289 		else							\
3290 			first = 0;					\
3291 		sbuf_printf(sb, name);					\
3292 	}								\
3293 } while (0)
3294 			ADD_FLAG(G_MIRROR_DISK_FLAG_DIRTY, "DIRTY");
3295 			ADD_FLAG(G_MIRROR_DISK_FLAG_HARDCODED, "HARDCODED");
3296 			ADD_FLAG(G_MIRROR_DISK_FLAG_INACTIVE, "INACTIVE");
3297 			ADD_FLAG(G_MIRROR_DISK_FLAG_SYNCHRONIZING,
3298 			    "SYNCHRONIZING");
3299 			ADD_FLAG(G_MIRROR_DISK_FLAG_FORCE_SYNC, "FORCE_SYNC");
3300 			ADD_FLAG(G_MIRROR_DISK_FLAG_BROKEN, "BROKEN");
3301 #undef	ADD_FLAG
3302 		}
3303 		sbuf_printf(sb, "</Flags>\n");
3304 		sbuf_printf(sb, "%s<Priority>%u</Priority>\n", indent,
3305 		    disk->d_priority);
3306 		sbuf_printf(sb, "%s<State>%s</State>\n", indent,
3307 		    g_mirror_disk_state2str(disk->d_state));
3308 		sx_xunlock(&sc->sc_lock);
3309 		g_topology_lock();
3310 	} else {
3311 		g_topology_unlock();
3312 		sx_xlock(&sc->sc_lock);
3313 		sbuf_printf(sb, "%s<Type>", indent);
3314 		switch (sc->sc_type) {
3315 		case G_MIRROR_TYPE_AUTOMATIC:
3316 			sbuf_printf(sb, "AUTOMATIC");
3317 			break;
3318 		case G_MIRROR_TYPE_MANUAL:
3319 			sbuf_printf(sb, "MANUAL");
3320 			break;
3321 		default:
3322 			sbuf_printf(sb, "UNKNOWN");
3323 			break;
3324 		}
3325 		sbuf_printf(sb, "</Type>\n");
3326 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)sc->sc_id);
3327 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent, sc->sc_syncid);
3328 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent, sc->sc_genid);
3329 		sbuf_printf(sb, "%s<Flags>", indent);
3330 		if (sc->sc_flags == 0)
3331 			sbuf_printf(sb, "NONE");
3332 		else {
3333 			int first = 1;
3334 
3335 #define	ADD_FLAG(flag, name)	do {					\
3336 	if ((sc->sc_flags & (flag)) != 0) {				\
3337 		if (!first)						\
3338 			sbuf_printf(sb, ", ");				\
3339 		else							\
3340 			first = 0;					\
3341 		sbuf_printf(sb, name);					\
3342 	}								\
3343 } while (0)
3344 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOFAILSYNC, "NOFAILSYNC");
3345 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOAUTOSYNC, "NOAUTOSYNC");
3346 #undef	ADD_FLAG
3347 		}
3348 		sbuf_printf(sb, "</Flags>\n");
3349 		sbuf_printf(sb, "%s<Slice>%u</Slice>\n", indent,
3350 		    (u_int)sc->sc_slice);
3351 		sbuf_printf(sb, "%s<Balance>%s</Balance>\n", indent,
3352 		    balance_name(sc->sc_balance));
3353 		sbuf_printf(sb, "%s<Components>%u</Components>\n", indent,
3354 		    sc->sc_ndisks);
3355 		sbuf_printf(sb, "%s<State>", indent);
3356 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
3357 			sbuf_printf(sb, "%s", "STARTING");
3358 		else if (sc->sc_ndisks ==
3359 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE))
3360 			sbuf_printf(sb, "%s", "COMPLETE");
3361 		else
3362 			sbuf_printf(sb, "%s", "DEGRADED");
3363 		sbuf_printf(sb, "</State>\n");
3364 		sx_xunlock(&sc->sc_lock);
3365 		g_topology_lock();
3366 	}
3367 }
3368 
3369 static void
3370 g_mirror_shutdown_post_sync(void *arg, int howto)
3371 {
3372 	struct g_class *mp;
3373 	struct g_geom *gp, *gp2;
3374 	struct g_mirror_softc *sc;
3375 	int error;
3376 
3377 	mp = arg;
3378 	g_topology_lock();
3379 	g_mirror_shutdown = 1;
3380 	LIST_FOREACH_SAFE(gp, &mp->geom, geom, gp2) {
3381 		if ((sc = gp->softc) == NULL)
3382 			continue;
3383 		/* Skip synchronization geom. */
3384 		if (gp == sc->sc_sync.ds_geom)
3385 			continue;
3386 		g_topology_unlock();
3387 		sx_xlock(&sc->sc_lock);
3388 		g_mirror_idle(sc, -1);
3389 		g_cancel_event(sc);
3390 		error = g_mirror_destroy(sc, G_MIRROR_DESTROY_DELAYED);
3391 		if (error != 0)
3392 			sx_xunlock(&sc->sc_lock);
3393 		g_topology_lock();
3394 	}
3395 	g_topology_unlock();
3396 }
3397 
3398 static void
3399 g_mirror_init(struct g_class *mp)
3400 {
3401 
3402 	g_mirror_post_sync = EVENTHANDLER_REGISTER(shutdown_post_sync,
3403 	    g_mirror_shutdown_post_sync, mp, SHUTDOWN_PRI_FIRST);
3404 	if (g_mirror_post_sync == NULL)
3405 		G_MIRROR_DEBUG(0, "Warning! Cannot register shutdown event.");
3406 }
3407 
3408 static void
3409 g_mirror_fini(struct g_class *mp)
3410 {
3411 
3412 	if (g_mirror_post_sync != NULL)
3413 		EVENTHANDLER_DEREGISTER(shutdown_post_sync, g_mirror_post_sync);
3414 }
3415 
3416 DECLARE_GEOM_CLASS(g_mirror_class, g_mirror);
3417