xref: /freebsd/sys/geom/mirror/g_mirror.c (revision 36712a94975f5bd0d26c85377283b49a2369c82f)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2004-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/bio.h>
35 #include <sys/eventhandler.h>
36 #include <sys/fail.h>
37 #include <sys/kernel.h>
38 #include <sys/kthread.h>
39 #include <sys/limits.h>
40 #include <sys/lock.h>
41 #include <sys/malloc.h>
42 #include <sys/mutex.h>
43 #include <sys/proc.h>
44 #include <sys/sbuf.h>
45 #include <sys/sched.h>
46 #include <sys/sx.h>
47 #include <sys/sysctl.h>
48 
49 #include <geom/geom.h>
50 #include <geom/geom_dbg.h>
51 #include <geom/mirror/g_mirror.h>
52 
53 FEATURE(geom_mirror, "GEOM mirroring support");
54 
55 static MALLOC_DEFINE(M_MIRROR, "mirror_data", "GEOM_MIRROR Data");
56 
57 SYSCTL_DECL(_kern_geom);
58 static SYSCTL_NODE(_kern_geom, OID_AUTO, mirror, CTLFLAG_RW, 0,
59     "GEOM_MIRROR stuff");
60 int g_mirror_debug = 0;
61 SYSCTL_INT(_kern_geom_mirror, OID_AUTO, debug, CTLFLAG_RWTUN, &g_mirror_debug, 0,
62     "Debug level");
63 bool g_launch_mirror_before_timeout = true;
64 SYSCTL_BOOL(_kern_geom_mirror, OID_AUTO, launch_mirror_before_timeout,
65     CTLFLAG_RWTUN, &g_launch_mirror_before_timeout, 0,
66     "If false, force gmirror to wait out the full kern.geom.mirror.timeout "
67     "before launching mirrors");
68 static u_int g_mirror_timeout = 4;
69 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, timeout, CTLFLAG_RWTUN, &g_mirror_timeout,
70     0, "Time to wait on all mirror components");
71 static u_int g_mirror_idletime = 5;
72 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, idletime, CTLFLAG_RWTUN,
73     &g_mirror_idletime, 0, "Mark components as clean when idling");
74 static u_int g_mirror_disconnect_on_failure = 1;
75 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, disconnect_on_failure, CTLFLAG_RWTUN,
76     &g_mirror_disconnect_on_failure, 0, "Disconnect component on I/O failure.");
77 static u_int g_mirror_syncreqs = 2;
78 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, sync_requests, CTLFLAG_RDTUN,
79     &g_mirror_syncreqs, 0, "Parallel synchronization I/O requests.");
80 static u_int g_mirror_sync_period = 5;
81 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, sync_update_period, CTLFLAG_RWTUN,
82     &g_mirror_sync_period, 0,
83     "Metadata update period during synchronization, in seconds");
84 
85 #define	MSLEEP(ident, mtx, priority, wmesg, timeout)	do {		\
86 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, (ident));	\
87 	msleep((ident), (mtx), (priority), (wmesg), (timeout));		\
88 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, (ident));	\
89 } while (0)
90 
91 static eventhandler_tag g_mirror_post_sync = NULL;
92 static int g_mirror_shutdown = 0;
93 
94 static g_ctl_destroy_geom_t g_mirror_destroy_geom;
95 static g_taste_t g_mirror_taste;
96 static g_init_t g_mirror_init;
97 static g_fini_t g_mirror_fini;
98 static g_provgone_t g_mirror_providergone;
99 static g_resize_t g_mirror_resize;
100 
101 struct g_class g_mirror_class = {
102 	.name = G_MIRROR_CLASS_NAME,
103 	.version = G_VERSION,
104 	.ctlreq = g_mirror_config,
105 	.taste = g_mirror_taste,
106 	.destroy_geom = g_mirror_destroy_geom,
107 	.init = g_mirror_init,
108 	.fini = g_mirror_fini,
109 	.providergone = g_mirror_providergone,
110 	.resize = g_mirror_resize
111 };
112 
113 
114 static void g_mirror_destroy_provider(struct g_mirror_softc *sc);
115 static int g_mirror_update_disk(struct g_mirror_disk *disk, u_int state);
116 static void g_mirror_update_device(struct g_mirror_softc *sc, bool force);
117 static void g_mirror_dumpconf(struct sbuf *sb, const char *indent,
118     struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp);
119 static int g_mirror_refresh_device(struct g_mirror_softc *sc,
120     const struct g_provider *pp, const struct g_mirror_metadata *md);
121 static void g_mirror_sync_reinit(const struct g_mirror_disk *disk,
122     struct bio *bp, off_t offset);
123 static void g_mirror_sync_stop(struct g_mirror_disk *disk, int type);
124 static void g_mirror_register_request(struct g_mirror_softc *sc,
125     struct bio *bp);
126 static void g_mirror_sync_release(struct g_mirror_softc *sc);
127 
128 
129 static const char *
130 g_mirror_disk_state2str(int state)
131 {
132 
133 	switch (state) {
134 	case G_MIRROR_DISK_STATE_NONE:
135 		return ("NONE");
136 	case G_MIRROR_DISK_STATE_NEW:
137 		return ("NEW");
138 	case G_MIRROR_DISK_STATE_ACTIVE:
139 		return ("ACTIVE");
140 	case G_MIRROR_DISK_STATE_STALE:
141 		return ("STALE");
142 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
143 		return ("SYNCHRONIZING");
144 	case G_MIRROR_DISK_STATE_DISCONNECTED:
145 		return ("DISCONNECTED");
146 	case G_MIRROR_DISK_STATE_DESTROY:
147 		return ("DESTROY");
148 	default:
149 		return ("INVALID");
150 	}
151 }
152 
153 static const char *
154 g_mirror_device_state2str(int state)
155 {
156 
157 	switch (state) {
158 	case G_MIRROR_DEVICE_STATE_STARTING:
159 		return ("STARTING");
160 	case G_MIRROR_DEVICE_STATE_RUNNING:
161 		return ("RUNNING");
162 	default:
163 		return ("INVALID");
164 	}
165 }
166 
167 static const char *
168 g_mirror_get_diskname(struct g_mirror_disk *disk)
169 {
170 
171 	if (disk->d_consumer == NULL || disk->d_consumer->provider == NULL)
172 		return ("[unknown]");
173 	return (disk->d_name);
174 }
175 
176 /*
177  * --- Events handling functions ---
178  * Events in geom_mirror are used to maintain disks and device status
179  * from one thread to simplify locking.
180  */
181 static void
182 g_mirror_event_free(struct g_mirror_event *ep)
183 {
184 
185 	free(ep, M_MIRROR);
186 }
187 
188 int
189 g_mirror_event_send(void *arg, int state, int flags)
190 {
191 	struct g_mirror_softc *sc;
192 	struct g_mirror_disk *disk;
193 	struct g_mirror_event *ep;
194 	int error;
195 
196 	ep = malloc(sizeof(*ep), M_MIRROR, M_WAITOK);
197 	G_MIRROR_DEBUG(4, "%s: Sending event %p.", __func__, ep);
198 	if ((flags & G_MIRROR_EVENT_DEVICE) != 0) {
199 		disk = NULL;
200 		sc = arg;
201 	} else {
202 		disk = arg;
203 		sc = disk->d_softc;
204 	}
205 	ep->e_disk = disk;
206 	ep->e_state = state;
207 	ep->e_flags = flags;
208 	ep->e_error = 0;
209 	mtx_lock(&sc->sc_events_mtx);
210 	TAILQ_INSERT_TAIL(&sc->sc_events, ep, e_next);
211 	mtx_unlock(&sc->sc_events_mtx);
212 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
213 	mtx_lock(&sc->sc_queue_mtx);
214 	wakeup(sc);
215 	mtx_unlock(&sc->sc_queue_mtx);
216 	if ((flags & G_MIRROR_EVENT_DONTWAIT) != 0)
217 		return (0);
218 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, ep);
219 	sx_xunlock(&sc->sc_lock);
220 	while ((ep->e_flags & G_MIRROR_EVENT_DONE) == 0) {
221 		mtx_lock(&sc->sc_events_mtx);
222 		MSLEEP(ep, &sc->sc_events_mtx, PRIBIO | PDROP, "m:event",
223 		    hz * 5);
224 	}
225 	error = ep->e_error;
226 	g_mirror_event_free(ep);
227 	sx_xlock(&sc->sc_lock);
228 	return (error);
229 }
230 
231 static struct g_mirror_event *
232 g_mirror_event_first(struct g_mirror_softc *sc)
233 {
234 	struct g_mirror_event *ep;
235 
236 	mtx_lock(&sc->sc_events_mtx);
237 	ep = TAILQ_FIRST(&sc->sc_events);
238 	mtx_unlock(&sc->sc_events_mtx);
239 	return (ep);
240 }
241 
242 static void
243 g_mirror_event_remove(struct g_mirror_softc *sc, struct g_mirror_event *ep)
244 {
245 
246 	mtx_lock(&sc->sc_events_mtx);
247 	TAILQ_REMOVE(&sc->sc_events, ep, e_next);
248 	mtx_unlock(&sc->sc_events_mtx);
249 }
250 
251 static void
252 g_mirror_event_cancel(struct g_mirror_disk *disk)
253 {
254 	struct g_mirror_softc *sc;
255 	struct g_mirror_event *ep, *tmpep;
256 
257 	sc = disk->d_softc;
258 	sx_assert(&sc->sc_lock, SX_XLOCKED);
259 
260 	mtx_lock(&sc->sc_events_mtx);
261 	TAILQ_FOREACH_SAFE(ep, &sc->sc_events, e_next, tmpep) {
262 		if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0)
263 			continue;
264 		if (ep->e_disk != disk)
265 			continue;
266 		TAILQ_REMOVE(&sc->sc_events, ep, e_next);
267 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
268 			g_mirror_event_free(ep);
269 		else {
270 			ep->e_error = ECANCELED;
271 			wakeup(ep);
272 		}
273 	}
274 	mtx_unlock(&sc->sc_events_mtx);
275 }
276 
277 /*
278  * Return the number of disks in given state.
279  * If state is equal to -1, count all connected disks.
280  */
281 u_int
282 g_mirror_ndisks(struct g_mirror_softc *sc, int state)
283 {
284 	struct g_mirror_disk *disk;
285 	u_int n = 0;
286 
287 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
288 		if (state == -1 || disk->d_state == state)
289 			n++;
290 	}
291 	return (n);
292 }
293 
294 /*
295  * Find a disk in mirror by its disk ID.
296  */
297 static struct g_mirror_disk *
298 g_mirror_id2disk(struct g_mirror_softc *sc, uint32_t id)
299 {
300 	struct g_mirror_disk *disk;
301 
302 	sx_assert(&sc->sc_lock, SX_XLOCKED);
303 
304 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
305 		if (disk->d_id == id)
306 			return (disk);
307 	}
308 	return (NULL);
309 }
310 
311 static u_int
312 g_mirror_nrequests(struct g_mirror_softc *sc, struct g_consumer *cp)
313 {
314 	struct bio *bp;
315 	u_int nreqs = 0;
316 
317 	mtx_lock(&sc->sc_queue_mtx);
318 	TAILQ_FOREACH(bp, &sc->sc_queue, bio_queue) {
319 		if (bp->bio_from == cp)
320 			nreqs++;
321 	}
322 	mtx_unlock(&sc->sc_queue_mtx);
323 	return (nreqs);
324 }
325 
326 static int
327 g_mirror_is_busy(struct g_mirror_softc *sc, struct g_consumer *cp)
328 {
329 
330 	if (cp->index > 0) {
331 		G_MIRROR_DEBUG(2,
332 		    "I/O requests for %s exist, can't destroy it now.",
333 		    cp->provider->name);
334 		return (1);
335 	}
336 	if (g_mirror_nrequests(sc, cp) > 0) {
337 		G_MIRROR_DEBUG(2,
338 		    "I/O requests for %s in queue, can't destroy it now.",
339 		    cp->provider->name);
340 		return (1);
341 	}
342 	return (0);
343 }
344 
345 static void
346 g_mirror_destroy_consumer(void *arg, int flags __unused)
347 {
348 	struct g_consumer *cp;
349 
350 	g_topology_assert();
351 
352 	cp = arg;
353 	G_MIRROR_DEBUG(1, "Consumer %s destroyed.", cp->provider->name);
354 	g_detach(cp);
355 	g_destroy_consumer(cp);
356 }
357 
358 static void
359 g_mirror_kill_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
360 {
361 	struct g_provider *pp;
362 	int retaste_wait;
363 
364 	g_topology_assert();
365 
366 	cp->private = NULL;
367 	if (g_mirror_is_busy(sc, cp))
368 		return;
369 	pp = cp->provider;
370 	retaste_wait = 0;
371 	if (cp->acw == 1) {
372 		if ((pp->geom->flags & G_GEOM_WITHER) == 0)
373 			retaste_wait = 1;
374 	}
375 	G_MIRROR_DEBUG(2, "Access %s r%dw%de%d = %d", pp->name, -cp->acr,
376 	    -cp->acw, -cp->ace, 0);
377 	if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
378 		g_access(cp, -cp->acr, -cp->acw, -cp->ace);
379 	if (retaste_wait) {
380 		/*
381 		 * After retaste event was send (inside g_access()), we can send
382 		 * event to detach and destroy consumer.
383 		 * A class, which has consumer to the given provider connected
384 		 * will not receive retaste event for the provider.
385 		 * This is the way how I ignore retaste events when I close
386 		 * consumers opened for write: I detach and destroy consumer
387 		 * after retaste event is sent.
388 		 */
389 		g_post_event(g_mirror_destroy_consumer, cp, M_WAITOK, NULL);
390 		return;
391 	}
392 	G_MIRROR_DEBUG(1, "Consumer %s destroyed.", pp->name);
393 	g_detach(cp);
394 	g_destroy_consumer(cp);
395 }
396 
397 static int
398 g_mirror_connect_disk(struct g_mirror_disk *disk, struct g_provider *pp)
399 {
400 	struct g_consumer *cp;
401 	int error;
402 
403 	g_topology_assert_not();
404 	KASSERT(disk->d_consumer == NULL,
405 	    ("Disk already connected (device %s).", disk->d_softc->sc_name));
406 
407 	g_topology_lock();
408 	cp = g_new_consumer(disk->d_softc->sc_geom);
409 	cp->flags |= G_CF_DIRECT_RECEIVE;
410 	error = g_attach(cp, pp);
411 	if (error != 0) {
412 		g_destroy_consumer(cp);
413 		g_topology_unlock();
414 		return (error);
415 	}
416 	error = g_access(cp, 1, 1, 1);
417 	if (error != 0) {
418 		g_detach(cp);
419 		g_destroy_consumer(cp);
420 		g_topology_unlock();
421 		G_MIRROR_DEBUG(0, "Cannot open consumer %s (error=%d).",
422 		    pp->name, error);
423 		return (error);
424 	}
425 	g_topology_unlock();
426 	disk->d_consumer = cp;
427 	disk->d_consumer->private = disk;
428 	disk->d_consumer->index = 0;
429 
430 	G_MIRROR_DEBUG(2, "Disk %s connected.", g_mirror_get_diskname(disk));
431 	return (0);
432 }
433 
434 static void
435 g_mirror_disconnect_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
436 {
437 
438 	g_topology_assert();
439 
440 	if (cp == NULL)
441 		return;
442 	if (cp->provider != NULL)
443 		g_mirror_kill_consumer(sc, cp);
444 	else
445 		g_destroy_consumer(cp);
446 }
447 
448 /*
449  * Initialize disk. This means allocate memory, create consumer, attach it
450  * to the provider and open access (r1w1e1) to it.
451  */
452 static struct g_mirror_disk *
453 g_mirror_init_disk(struct g_mirror_softc *sc, struct g_provider *pp,
454     struct g_mirror_metadata *md, int *errorp)
455 {
456 	struct g_mirror_disk *disk;
457 	int i, error;
458 
459 	disk = malloc(sizeof(*disk), M_MIRROR, M_NOWAIT | M_ZERO);
460 	if (disk == NULL) {
461 		error = ENOMEM;
462 		goto fail;
463 	}
464 	disk->d_softc = sc;
465 	error = g_mirror_connect_disk(disk, pp);
466 	if (error != 0)
467 		goto fail;
468 	disk->d_id = md->md_did;
469 	disk->d_state = G_MIRROR_DISK_STATE_NONE;
470 	disk->d_priority = md->md_priority;
471 	disk->d_flags = md->md_dflags;
472 	error = g_getattr("GEOM::candelete", disk->d_consumer, &i);
473 	if (error == 0 && i != 0)
474 		disk->d_flags |= G_MIRROR_DISK_FLAG_CANDELETE;
475 	if (md->md_provider[0] != '\0')
476 		disk->d_flags |= G_MIRROR_DISK_FLAG_HARDCODED;
477 	disk->d_sync.ds_consumer = NULL;
478 	disk->d_sync.ds_offset = md->md_sync_offset;
479 	disk->d_sync.ds_offset_done = md->md_sync_offset;
480 	disk->d_sync.ds_update_ts = time_uptime;
481 	disk->d_genid = md->md_genid;
482 	disk->d_sync.ds_syncid = md->md_syncid;
483 	disk->d_init_ndisks = md->md_all;
484 	disk->d_init_slice = md->md_slice;
485 	disk->d_init_balance = md->md_balance;
486 	disk->d_init_mediasize = md->md_mediasize;
487 	if (errorp != NULL)
488 		*errorp = 0;
489 	return (disk);
490 fail:
491 	if (errorp != NULL)
492 		*errorp = error;
493 	if (disk != NULL)
494 		free(disk, M_MIRROR);
495 	return (NULL);
496 }
497 
498 static void
499 g_mirror_destroy_disk(struct g_mirror_disk *disk)
500 {
501 	struct g_mirror_softc *sc;
502 
503 	g_topology_assert_not();
504 	sc = disk->d_softc;
505 	sx_assert(&sc->sc_lock, SX_XLOCKED);
506 
507 	g_topology_lock();
508 	LIST_REMOVE(disk, d_next);
509 	g_topology_unlock();
510 	g_mirror_event_cancel(disk);
511 	if (sc->sc_hint == disk)
512 		sc->sc_hint = NULL;
513 	switch (disk->d_state) {
514 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
515 		g_mirror_sync_stop(disk, 1);
516 		/* FALLTHROUGH */
517 	case G_MIRROR_DISK_STATE_NEW:
518 	case G_MIRROR_DISK_STATE_STALE:
519 	case G_MIRROR_DISK_STATE_ACTIVE:
520 		g_topology_lock();
521 		g_mirror_disconnect_consumer(sc, disk->d_consumer);
522 		g_topology_unlock();
523 		free(disk, M_MIRROR);
524 		break;
525 	default:
526 		KASSERT(0 == 1, ("Wrong disk state (%s, %s).",
527 		    g_mirror_get_diskname(disk),
528 		    g_mirror_disk_state2str(disk->d_state)));
529 	}
530 }
531 
532 static void
533 g_mirror_free_device(struct g_mirror_softc *sc)
534 {
535 
536 	g_topology_assert();
537 
538 	mtx_destroy(&sc->sc_queue_mtx);
539 	mtx_destroy(&sc->sc_events_mtx);
540 	mtx_destroy(&sc->sc_done_mtx);
541 	sx_destroy(&sc->sc_lock);
542 	free(sc, M_MIRROR);
543 }
544 
545 static void
546 g_mirror_providergone(struct g_provider *pp)
547 {
548 	struct g_mirror_softc *sc = pp->private;
549 
550 	if ((--sc->sc_refcnt) == 0)
551 		g_mirror_free_device(sc);
552 }
553 
554 static void
555 g_mirror_destroy_device(struct g_mirror_softc *sc)
556 {
557 	struct g_mirror_disk *disk;
558 	struct g_mirror_event *ep;
559 	struct g_geom *gp;
560 	struct g_consumer *cp, *tmpcp;
561 
562 	g_topology_assert_not();
563 	sx_assert(&sc->sc_lock, SX_XLOCKED);
564 
565 	gp = sc->sc_geom;
566 	if (sc->sc_provider != NULL)
567 		g_mirror_destroy_provider(sc);
568 	for (disk = LIST_FIRST(&sc->sc_disks); disk != NULL;
569 	    disk = LIST_FIRST(&sc->sc_disks)) {
570 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
571 		g_mirror_update_metadata(disk);
572 		g_mirror_destroy_disk(disk);
573 	}
574 	while ((ep = g_mirror_event_first(sc)) != NULL) {
575 		g_mirror_event_remove(sc, ep);
576 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
577 			g_mirror_event_free(ep);
578 		else {
579 			ep->e_error = ECANCELED;
580 			ep->e_flags |= G_MIRROR_EVENT_DONE;
581 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, ep);
582 			mtx_lock(&sc->sc_events_mtx);
583 			wakeup(ep);
584 			mtx_unlock(&sc->sc_events_mtx);
585 		}
586 	}
587 	callout_drain(&sc->sc_callout);
588 
589 	g_topology_lock();
590 	LIST_FOREACH_SAFE(cp, &sc->sc_sync.ds_geom->consumer, consumer, tmpcp) {
591 		g_mirror_disconnect_consumer(sc, cp);
592 	}
593 	g_wither_geom(sc->sc_sync.ds_geom, ENXIO);
594 	G_MIRROR_DEBUG(0, "Device %s destroyed.", gp->name);
595 	g_wither_geom(gp, ENXIO);
596 	sx_xunlock(&sc->sc_lock);
597 	if ((--sc->sc_refcnt) == 0)
598 		g_mirror_free_device(sc);
599 	g_topology_unlock();
600 }
601 
602 static void
603 g_mirror_orphan(struct g_consumer *cp)
604 {
605 	struct g_mirror_disk *disk;
606 
607 	g_topology_assert();
608 
609 	disk = cp->private;
610 	if (disk == NULL)
611 		return;
612 	disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
613 	g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
614 	    G_MIRROR_EVENT_DONTWAIT);
615 }
616 
617 /*
618  * Function should return the next active disk on the list.
619  * It is possible that it will be the same disk as given.
620  * If there are no active disks on list, NULL is returned.
621  */
622 static __inline struct g_mirror_disk *
623 g_mirror_find_next(struct g_mirror_softc *sc, struct g_mirror_disk *disk)
624 {
625 	struct g_mirror_disk *dp;
626 
627 	for (dp = LIST_NEXT(disk, d_next); dp != disk;
628 	    dp = LIST_NEXT(dp, d_next)) {
629 		if (dp == NULL)
630 			dp = LIST_FIRST(&sc->sc_disks);
631 		if (dp->d_state == G_MIRROR_DISK_STATE_ACTIVE)
632 			break;
633 	}
634 	if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
635 		return (NULL);
636 	return (dp);
637 }
638 
639 static struct g_mirror_disk *
640 g_mirror_get_disk(struct g_mirror_softc *sc)
641 {
642 	struct g_mirror_disk *disk;
643 
644 	if (sc->sc_hint == NULL) {
645 		sc->sc_hint = LIST_FIRST(&sc->sc_disks);
646 		if (sc->sc_hint == NULL)
647 			return (NULL);
648 	}
649 	disk = sc->sc_hint;
650 	if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE) {
651 		disk = g_mirror_find_next(sc, disk);
652 		if (disk == NULL)
653 			return (NULL);
654 	}
655 	sc->sc_hint = g_mirror_find_next(sc, disk);
656 	return (disk);
657 }
658 
659 static int
660 g_mirror_write_metadata(struct g_mirror_disk *disk,
661     struct g_mirror_metadata *md)
662 {
663 	struct g_mirror_softc *sc;
664 	struct g_consumer *cp;
665 	off_t offset, length;
666 	u_char *sector;
667 	int error = 0;
668 
669 	g_topology_assert_not();
670 	sc = disk->d_softc;
671 	sx_assert(&sc->sc_lock, SX_LOCKED);
672 
673 	cp = disk->d_consumer;
674 	KASSERT(cp != NULL, ("NULL consumer (%s).", sc->sc_name));
675 	KASSERT(cp->provider != NULL, ("NULL provider (%s).", sc->sc_name));
676 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
677 	    ("Consumer %s closed? (r%dw%de%d).", cp->provider->name, cp->acr,
678 	    cp->acw, cp->ace));
679 	length = cp->provider->sectorsize;
680 	offset = cp->provider->mediasize - length;
681 	sector = malloc((size_t)length, M_MIRROR, M_WAITOK | M_ZERO);
682 	if (md != NULL &&
683 	    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_WIPE) == 0) {
684 		/*
685 		 * Handle the case, when the size of parent provider reduced.
686 		 */
687 		if (offset < md->md_mediasize)
688 			error = ENOSPC;
689 		else
690 			mirror_metadata_encode(md, sector);
691 	}
692 	KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_metadata_write, error);
693 	if (error == 0)
694 		error = g_write_data(cp, offset, sector, length);
695 	free(sector, M_MIRROR);
696 	if (error != 0) {
697 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_BROKEN) == 0) {
698 			disk->d_flags |= G_MIRROR_DISK_FLAG_BROKEN;
699 			G_MIRROR_DEBUG(0, "Cannot write metadata on %s "
700 			    "(device=%s, error=%d).",
701 			    g_mirror_get_diskname(disk), sc->sc_name, error);
702 		} else {
703 			G_MIRROR_DEBUG(1, "Cannot write metadata on %s "
704 			    "(device=%s, error=%d).",
705 			    g_mirror_get_diskname(disk), sc->sc_name, error);
706 		}
707 		if (g_mirror_disconnect_on_failure &&
708 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 1) {
709 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
710 			g_mirror_event_send(disk,
711 			    G_MIRROR_DISK_STATE_DISCONNECTED,
712 			    G_MIRROR_EVENT_DONTWAIT);
713 		}
714 	}
715 	return (error);
716 }
717 
718 static int
719 g_mirror_clear_metadata(struct g_mirror_disk *disk)
720 {
721 	int error;
722 
723 	g_topology_assert_not();
724 	sx_assert(&disk->d_softc->sc_lock, SX_LOCKED);
725 
726 	if (disk->d_softc->sc_type != G_MIRROR_TYPE_AUTOMATIC)
727 		return (0);
728 	error = g_mirror_write_metadata(disk, NULL);
729 	if (error == 0) {
730 		G_MIRROR_DEBUG(2, "Metadata on %s cleared.",
731 		    g_mirror_get_diskname(disk));
732 	} else {
733 		G_MIRROR_DEBUG(0,
734 		    "Cannot clear metadata on disk %s (error=%d).",
735 		    g_mirror_get_diskname(disk), error);
736 	}
737 	return (error);
738 }
739 
740 void
741 g_mirror_fill_metadata(struct g_mirror_softc *sc, struct g_mirror_disk *disk,
742     struct g_mirror_metadata *md)
743 {
744 
745 	strlcpy(md->md_magic, G_MIRROR_MAGIC, sizeof(md->md_magic));
746 	md->md_version = G_MIRROR_VERSION;
747 	strlcpy(md->md_name, sc->sc_name, sizeof(md->md_name));
748 	md->md_mid = sc->sc_id;
749 	md->md_all = sc->sc_ndisks;
750 	md->md_slice = sc->sc_slice;
751 	md->md_balance = sc->sc_balance;
752 	md->md_genid = sc->sc_genid;
753 	md->md_mediasize = sc->sc_mediasize;
754 	md->md_sectorsize = sc->sc_sectorsize;
755 	md->md_mflags = (sc->sc_flags & G_MIRROR_DEVICE_FLAG_MASK);
756 	bzero(md->md_provider, sizeof(md->md_provider));
757 	if (disk == NULL) {
758 		md->md_did = arc4random();
759 		md->md_priority = 0;
760 		md->md_syncid = 0;
761 		md->md_dflags = 0;
762 		md->md_sync_offset = 0;
763 		md->md_provsize = 0;
764 	} else {
765 		md->md_did = disk->d_id;
766 		md->md_priority = disk->d_priority;
767 		md->md_syncid = disk->d_sync.ds_syncid;
768 		md->md_dflags = (disk->d_flags & G_MIRROR_DISK_FLAG_MASK);
769 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
770 			md->md_sync_offset = disk->d_sync.ds_offset_done;
771 		else
772 			md->md_sync_offset = 0;
773 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_HARDCODED) != 0) {
774 			strlcpy(md->md_provider,
775 			    disk->d_consumer->provider->name,
776 			    sizeof(md->md_provider));
777 		}
778 		md->md_provsize = disk->d_consumer->provider->mediasize;
779 	}
780 }
781 
782 void
783 g_mirror_update_metadata(struct g_mirror_disk *disk)
784 {
785 	struct g_mirror_softc *sc;
786 	struct g_mirror_metadata md;
787 	int error;
788 
789 	g_topology_assert_not();
790 	sc = disk->d_softc;
791 	sx_assert(&sc->sc_lock, SX_LOCKED);
792 
793 	if (sc->sc_type != G_MIRROR_TYPE_AUTOMATIC)
794 		return;
795 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_WIPE) == 0)
796 		g_mirror_fill_metadata(sc, disk, &md);
797 	error = g_mirror_write_metadata(disk, &md);
798 	if (error == 0) {
799 		G_MIRROR_DEBUG(2, "Metadata on %s updated.",
800 		    g_mirror_get_diskname(disk));
801 	} else {
802 		G_MIRROR_DEBUG(0,
803 		    "Cannot update metadata on disk %s (error=%d).",
804 		    g_mirror_get_diskname(disk), error);
805 	}
806 }
807 
808 static void
809 g_mirror_bump_syncid(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_syncid++;
820 	G_MIRROR_DEBUG(1, "Device %s: syncid bumped to %u.", sc->sc_name,
821 	    sc->sc_syncid);
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_sync.ds_syncid = sc->sc_syncid;
826 			g_mirror_update_metadata(disk);
827 		}
828 	}
829 }
830 
831 static void
832 g_mirror_bump_genid(struct g_mirror_softc *sc)
833 {
834 	struct g_mirror_disk *disk;
835 
836 	g_topology_assert_not();
837 	sx_assert(&sc->sc_lock, SX_XLOCKED);
838 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
839 	    ("%s called with no active disks (device=%s).", __func__,
840 	    sc->sc_name));
841 
842 	sc->sc_genid++;
843 	G_MIRROR_DEBUG(1, "Device %s: genid bumped to %u.", sc->sc_name,
844 	    sc->sc_genid);
845 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
846 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
847 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
848 			disk->d_genid = sc->sc_genid;
849 			g_mirror_update_metadata(disk);
850 		}
851 	}
852 }
853 
854 static int
855 g_mirror_idle(struct g_mirror_softc *sc, int acw)
856 {
857 	struct g_mirror_disk *disk;
858 	int timeout;
859 
860 	g_topology_assert_not();
861 	sx_assert(&sc->sc_lock, SX_XLOCKED);
862 
863 	if (sc->sc_provider == NULL)
864 		return (0);
865 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
866 		return (0);
867 	if (sc->sc_idle)
868 		return (0);
869 	if (sc->sc_writes > 0)
870 		return (0);
871 	if (acw > 0 || (acw == -1 && sc->sc_provider->acw > 0)) {
872 		timeout = g_mirror_idletime - (time_uptime - sc->sc_last_write);
873 		if (!g_mirror_shutdown && timeout > 0)
874 			return (timeout);
875 	}
876 	sc->sc_idle = 1;
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 clean.",
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 	return (0);
886 }
887 
888 static void
889 g_mirror_unidle(struct g_mirror_softc *sc)
890 {
891 	struct g_mirror_disk *disk;
892 
893 	g_topology_assert_not();
894 	sx_assert(&sc->sc_lock, SX_XLOCKED);
895 
896 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
897 		return;
898 	sc->sc_idle = 0;
899 	sc->sc_last_write = time_uptime;
900 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
901 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
902 			continue;
903 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as dirty.",
904 		    g_mirror_get_diskname(disk), sc->sc_name);
905 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
906 		g_mirror_update_metadata(disk);
907 	}
908 }
909 
910 static void
911 g_mirror_done(struct bio *bp)
912 {
913 	struct g_mirror_softc *sc;
914 
915 	sc = bp->bio_from->geom->softc;
916 	bp->bio_cflags = G_MIRROR_BIO_FLAG_REGULAR;
917 	mtx_lock(&sc->sc_queue_mtx);
918 	TAILQ_INSERT_TAIL(&sc->sc_queue, bp, bio_queue);
919 	mtx_unlock(&sc->sc_queue_mtx);
920 	wakeup(sc);
921 }
922 
923 static void
924 g_mirror_regular_request_error(struct g_mirror_softc *sc,
925     struct g_mirror_disk *disk, struct bio *bp)
926 {
927 
928 	if (bp->bio_cmd == BIO_FLUSH && bp->bio_error == EOPNOTSUPP)
929 		return;
930 
931 	if ((disk->d_flags & G_MIRROR_DISK_FLAG_BROKEN) == 0) {
932 		disk->d_flags |= G_MIRROR_DISK_FLAG_BROKEN;
933 		G_MIRROR_LOGREQ(0, bp, "Request failed (error=%d).",
934 		    bp->bio_error);
935 	} else {
936 		G_MIRROR_LOGREQ(1, bp, "Request failed (error=%d).",
937 		    bp->bio_error);
938 	}
939 	if (g_mirror_disconnect_on_failure &&
940 	    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 1) {
941 		if (bp->bio_error == ENXIO &&
942 		    bp->bio_cmd == BIO_READ)
943 			sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
944 		else if (bp->bio_error == ENXIO)
945 			sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID_NOW;
946 		else
947 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
948 		g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
949 		    G_MIRROR_EVENT_DONTWAIT);
950 	}
951 }
952 
953 static void
954 g_mirror_regular_request(struct g_mirror_softc *sc, struct bio *bp)
955 {
956 	struct g_mirror_disk *disk;
957 	struct bio *pbp;
958 
959 	g_topology_assert_not();
960 	KASSERT(sc->sc_provider == bp->bio_parent->bio_to,
961 	    ("regular request %p with unexpected origin", bp));
962 
963 	pbp = bp->bio_parent;
964 	bp->bio_from->index--;
965 	if (bp->bio_cmd == BIO_WRITE || bp->bio_cmd == BIO_DELETE)
966 		sc->sc_writes--;
967 	disk = bp->bio_from->private;
968 	if (disk == NULL) {
969 		g_topology_lock();
970 		g_mirror_kill_consumer(sc, bp->bio_from);
971 		g_topology_unlock();
972 	}
973 
974 	switch (bp->bio_cmd) {
975 	case BIO_READ:
976 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_regular_request_read,
977 		    bp->bio_error);
978 		break;
979 	case BIO_WRITE:
980 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_regular_request_write,
981 		    bp->bio_error);
982 		break;
983 	case BIO_DELETE:
984 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_regular_request_delete,
985 		    bp->bio_error);
986 		break;
987 	case BIO_FLUSH:
988 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_regular_request_flush,
989 		    bp->bio_error);
990 		break;
991 	}
992 
993 	pbp->bio_inbed++;
994 	KASSERT(pbp->bio_inbed <= pbp->bio_children,
995 	    ("bio_inbed (%u) is bigger than bio_children (%u).", pbp->bio_inbed,
996 	    pbp->bio_children));
997 	if (bp->bio_error == 0 && pbp->bio_error == 0) {
998 		G_MIRROR_LOGREQ(3, bp, "Request delivered.");
999 		g_destroy_bio(bp);
1000 		if (pbp->bio_children == pbp->bio_inbed) {
1001 			G_MIRROR_LOGREQ(3, pbp, "Request delivered.");
1002 			pbp->bio_completed = pbp->bio_length;
1003 			if (pbp->bio_cmd == BIO_WRITE ||
1004 			    pbp->bio_cmd == BIO_DELETE) {
1005 				TAILQ_REMOVE(&sc->sc_inflight, pbp, bio_queue);
1006 				/* Release delayed sync requests if possible. */
1007 				g_mirror_sync_release(sc);
1008 			}
1009 			g_io_deliver(pbp, pbp->bio_error);
1010 		}
1011 		return;
1012 	} else if (bp->bio_error != 0) {
1013 		if (pbp->bio_error == 0)
1014 			pbp->bio_error = bp->bio_error;
1015 		if (disk != NULL)
1016 			g_mirror_regular_request_error(sc, disk, bp);
1017 		switch (pbp->bio_cmd) {
1018 		case BIO_DELETE:
1019 		case BIO_WRITE:
1020 		case BIO_FLUSH:
1021 			pbp->bio_inbed--;
1022 			pbp->bio_children--;
1023 			break;
1024 		}
1025 	}
1026 	g_destroy_bio(bp);
1027 
1028 	switch (pbp->bio_cmd) {
1029 	case BIO_READ:
1030 		if (pbp->bio_inbed < pbp->bio_children)
1031 			break;
1032 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 1)
1033 			g_io_deliver(pbp, pbp->bio_error);
1034 		else {
1035 			pbp->bio_error = 0;
1036 			mtx_lock(&sc->sc_queue_mtx);
1037 			TAILQ_INSERT_TAIL(&sc->sc_queue, pbp, bio_queue);
1038 			mtx_unlock(&sc->sc_queue_mtx);
1039 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
1040 			wakeup(sc);
1041 		}
1042 		break;
1043 	case BIO_DELETE:
1044 	case BIO_WRITE:
1045 	case BIO_FLUSH:
1046 		if (pbp->bio_children == 0) {
1047 			/*
1048 			 * All requests failed.
1049 			 */
1050 		} else if (pbp->bio_inbed < pbp->bio_children) {
1051 			/* Do nothing. */
1052 			break;
1053 		} else if (pbp->bio_children == pbp->bio_inbed) {
1054 			/* Some requests succeeded. */
1055 			pbp->bio_error = 0;
1056 			pbp->bio_completed = pbp->bio_length;
1057 		}
1058 		if (pbp->bio_cmd == BIO_WRITE || pbp->bio_cmd == BIO_DELETE) {
1059 			TAILQ_REMOVE(&sc->sc_inflight, pbp, bio_queue);
1060 			/* Release delayed sync requests if possible. */
1061 			g_mirror_sync_release(sc);
1062 		}
1063 		g_io_deliver(pbp, pbp->bio_error);
1064 		break;
1065 	default:
1066 		KASSERT(1 == 0, ("Invalid request: %u.", pbp->bio_cmd));
1067 		break;
1068 	}
1069 }
1070 
1071 static void
1072 g_mirror_sync_done(struct bio *bp)
1073 {
1074 	struct g_mirror_softc *sc;
1075 
1076 	G_MIRROR_LOGREQ(3, bp, "Synchronization request delivered.");
1077 	sc = bp->bio_from->geom->softc;
1078 	bp->bio_cflags = G_MIRROR_BIO_FLAG_SYNC;
1079 	mtx_lock(&sc->sc_queue_mtx);
1080 	TAILQ_INSERT_TAIL(&sc->sc_queue, bp, bio_queue);
1081 	mtx_unlock(&sc->sc_queue_mtx);
1082 	wakeup(sc);
1083 }
1084 
1085 static void
1086 g_mirror_candelete(struct bio *bp)
1087 {
1088 	struct g_mirror_softc *sc;
1089 	struct g_mirror_disk *disk;
1090 	int val;
1091 
1092 	sc = bp->bio_to->private;
1093 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1094 		if (disk->d_flags & G_MIRROR_DISK_FLAG_CANDELETE)
1095 			break;
1096 	}
1097 	val = disk != NULL;
1098 	g_handleattr(bp, "GEOM::candelete", &val, sizeof(val));
1099 }
1100 
1101 static void
1102 g_mirror_kernel_dump(struct bio *bp)
1103 {
1104 	struct g_mirror_softc *sc;
1105 	struct g_mirror_disk *disk;
1106 	struct bio *cbp;
1107 	struct g_kerneldump *gkd;
1108 
1109 	/*
1110 	 * We configure dumping to the first component, because this component
1111 	 * will be used for reading with 'prefer' balance algorithm.
1112 	 * If the component with the highest priority is currently disconnected
1113 	 * we will not be able to read the dump after the reboot if it will be
1114 	 * connected and synchronized later. Can we do something better?
1115 	 */
1116 	sc = bp->bio_to->private;
1117 	disk = LIST_FIRST(&sc->sc_disks);
1118 
1119 	gkd = (struct g_kerneldump *)bp->bio_data;
1120 	if (gkd->length > bp->bio_to->mediasize)
1121 		gkd->length = bp->bio_to->mediasize;
1122 	cbp = g_clone_bio(bp);
1123 	if (cbp == NULL) {
1124 		g_io_deliver(bp, ENOMEM);
1125 		return;
1126 	}
1127 	cbp->bio_done = g_std_done;
1128 	g_io_request(cbp, disk->d_consumer);
1129 	G_MIRROR_DEBUG(1, "Kernel dump will go to %s.",
1130 	    g_mirror_get_diskname(disk));
1131 }
1132 
1133 static void
1134 g_mirror_start(struct bio *bp)
1135 {
1136 	struct g_mirror_softc *sc;
1137 
1138 	sc = bp->bio_to->private;
1139 	/*
1140 	 * If sc == NULL or there are no valid disks, provider's error
1141 	 * should be set and g_mirror_start() should not be called at all.
1142 	 */
1143 	KASSERT(sc != NULL && sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
1144 	    ("Provider's error should be set (error=%d)(mirror=%s).",
1145 	    bp->bio_to->error, bp->bio_to->name));
1146 	G_MIRROR_LOGREQ(3, bp, "Request received.");
1147 
1148 	switch (bp->bio_cmd) {
1149 	case BIO_READ:
1150 	case BIO_WRITE:
1151 	case BIO_DELETE:
1152 	case BIO_FLUSH:
1153 		break;
1154 	case BIO_GETATTR:
1155 		if (!strcmp(bp->bio_attribute, "GEOM::candelete")) {
1156 			g_mirror_candelete(bp);
1157 			return;
1158 		} else if (strcmp("GEOM::kerneldump", bp->bio_attribute) == 0) {
1159 			g_mirror_kernel_dump(bp);
1160 			return;
1161 		}
1162 		/* FALLTHROUGH */
1163 	default:
1164 		g_io_deliver(bp, EOPNOTSUPP);
1165 		return;
1166 	}
1167 	mtx_lock(&sc->sc_queue_mtx);
1168 	if (bp->bio_to->error != 0) {
1169 		mtx_unlock(&sc->sc_queue_mtx);
1170 		g_io_deliver(bp, bp->bio_to->error);
1171 		return;
1172 	}
1173 	TAILQ_INSERT_TAIL(&sc->sc_queue, bp, bio_queue);
1174 	mtx_unlock(&sc->sc_queue_mtx);
1175 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
1176 	wakeup(sc);
1177 }
1178 
1179 /*
1180  * Return TRUE if the given request is colliding with a in-progress
1181  * synchronization request.
1182  */
1183 static bool
1184 g_mirror_sync_collision(struct g_mirror_softc *sc, struct bio *bp)
1185 {
1186 	struct g_mirror_disk *disk;
1187 	struct bio *sbp;
1188 	off_t rstart, rend, sstart, send;
1189 	u_int i;
1190 
1191 	if (sc->sc_sync.ds_ndisks == 0)
1192 		return (false);
1193 	rstart = bp->bio_offset;
1194 	rend = bp->bio_offset + bp->bio_length;
1195 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1196 		if (disk->d_state != G_MIRROR_DISK_STATE_SYNCHRONIZING)
1197 			continue;
1198 		for (i = 0; i < g_mirror_syncreqs; i++) {
1199 			sbp = disk->d_sync.ds_bios[i];
1200 			if (sbp == NULL)
1201 				continue;
1202 			sstart = sbp->bio_offset;
1203 			send = sbp->bio_offset + sbp->bio_length;
1204 			if (rend > sstart && rstart < send)
1205 				return (true);
1206 		}
1207 	}
1208 	return (false);
1209 }
1210 
1211 /*
1212  * Return TRUE if the given sync request is colliding with a in-progress regular
1213  * request.
1214  */
1215 static bool
1216 g_mirror_regular_collision(struct g_mirror_softc *sc, struct bio *sbp)
1217 {
1218 	off_t rstart, rend, sstart, send;
1219 	struct bio *bp;
1220 
1221 	if (sc->sc_sync.ds_ndisks == 0)
1222 		return (false);
1223 	sstart = sbp->bio_offset;
1224 	send = sbp->bio_offset + sbp->bio_length;
1225 	TAILQ_FOREACH(bp, &sc->sc_inflight, bio_queue) {
1226 		rstart = bp->bio_offset;
1227 		rend = bp->bio_offset + bp->bio_length;
1228 		if (rend > sstart && rstart < send)
1229 			return (true);
1230 	}
1231 	return (false);
1232 }
1233 
1234 /*
1235  * Puts regular request onto delayed queue.
1236  */
1237 static void
1238 g_mirror_regular_delay(struct g_mirror_softc *sc, struct bio *bp)
1239 {
1240 
1241 	G_MIRROR_LOGREQ(2, bp, "Delaying request.");
1242 	TAILQ_INSERT_TAIL(&sc->sc_regular_delayed, bp, bio_queue);
1243 }
1244 
1245 /*
1246  * Puts synchronization request onto delayed queue.
1247  */
1248 static void
1249 g_mirror_sync_delay(struct g_mirror_softc *sc, struct bio *bp)
1250 {
1251 
1252 	G_MIRROR_LOGREQ(2, bp, "Delaying synchronization request.");
1253 	TAILQ_INSERT_TAIL(&sc->sc_sync_delayed, bp, bio_queue);
1254 }
1255 
1256 /*
1257  * Requeue delayed regular requests.
1258  */
1259 static void
1260 g_mirror_regular_release(struct g_mirror_softc *sc)
1261 {
1262 	struct bio *bp;
1263 
1264 	if ((bp = TAILQ_FIRST(&sc->sc_regular_delayed)) == NULL)
1265 		return;
1266 	if (g_mirror_sync_collision(sc, bp))
1267 		return;
1268 
1269 	G_MIRROR_DEBUG(2, "Requeuing regular requests after collision.");
1270 	mtx_lock(&sc->sc_queue_mtx);
1271 	TAILQ_CONCAT(&sc->sc_regular_delayed, &sc->sc_queue, bio_queue);
1272 	TAILQ_SWAP(&sc->sc_regular_delayed, &sc->sc_queue, bio, bio_queue);
1273 	mtx_unlock(&sc->sc_queue_mtx);
1274 }
1275 
1276 /*
1277  * Releases delayed sync requests which don't collide anymore with regular
1278  * requests.
1279  */
1280 static void
1281 g_mirror_sync_release(struct g_mirror_softc *sc)
1282 {
1283 	struct bio *bp, *bp2;
1284 
1285 	TAILQ_FOREACH_SAFE(bp, &sc->sc_sync_delayed, bio_queue, bp2) {
1286 		if (g_mirror_regular_collision(sc, bp))
1287 			continue;
1288 		TAILQ_REMOVE(&sc->sc_sync_delayed, bp, bio_queue);
1289 		G_MIRROR_LOGREQ(2, bp,
1290 		    "Releasing delayed synchronization request.");
1291 		g_io_request(bp, bp->bio_from);
1292 	}
1293 }
1294 
1295 /*
1296  * Free a synchronization request and clear its slot in the array.
1297  */
1298 static void
1299 g_mirror_sync_request_free(struct g_mirror_disk *disk, struct bio *bp)
1300 {
1301 	int idx;
1302 
1303 	if (disk != NULL && disk->d_sync.ds_bios != NULL) {
1304 		idx = (int)(uintptr_t)bp->bio_caller1;
1305 		KASSERT(disk->d_sync.ds_bios[idx] == bp,
1306 		    ("unexpected sync BIO at %p:%d", disk, idx));
1307 		disk->d_sync.ds_bios[idx] = NULL;
1308 	}
1309 	free(bp->bio_data, M_MIRROR);
1310 	g_destroy_bio(bp);
1311 }
1312 
1313 /*
1314  * Handle synchronization requests.
1315  * Every synchronization request is a two-step process: first, a read request is
1316  * sent to the mirror provider via the sync consumer. If that request completes
1317  * successfully, it is converted to a write and sent to the disk being
1318  * synchronized. If the write also completes successfully, the synchronization
1319  * offset is advanced and a new read request is submitted.
1320  */
1321 static void
1322 g_mirror_sync_request(struct g_mirror_softc *sc, struct bio *bp)
1323 {
1324 	struct g_mirror_disk *disk;
1325 	struct g_mirror_disk_sync *sync;
1326 
1327 	KASSERT((bp->bio_cmd == BIO_READ &&
1328 	    bp->bio_from->geom == sc->sc_sync.ds_geom) ||
1329 	    (bp->bio_cmd == BIO_WRITE && bp->bio_from->geom == sc->sc_geom),
1330 	    ("Sync BIO %p with unexpected origin", bp));
1331 
1332 	bp->bio_from->index--;
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 	sync = &disk->d_sync;
1345 
1346 	/*
1347 	 * Synchronization request.
1348 	 */
1349 	switch (bp->bio_cmd) {
1350 	case BIO_READ: {
1351 		struct g_consumer *cp;
1352 
1353 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_sync_request_read,
1354 		    bp->bio_error);
1355 
1356 		if (bp->bio_error != 0) {
1357 			G_MIRROR_LOGREQ(0, bp,
1358 			    "Synchronization request failed (error=%d).",
1359 			    bp->bio_error);
1360 
1361 			/*
1362 			 * The read error will trigger a syncid bump, so there's
1363 			 * no need to do that here.
1364 			 *
1365 			 * The read error handling for regular requests will
1366 			 * retry the read from all active mirrors before passing
1367 			 * the error back up, so there's no need to retry here.
1368 			 */
1369 			g_mirror_sync_request_free(disk, bp);
1370 			g_mirror_event_send(disk,
1371 			    G_MIRROR_DISK_STATE_DISCONNECTED,
1372 			    G_MIRROR_EVENT_DONTWAIT);
1373 			return;
1374 		}
1375 		G_MIRROR_LOGREQ(3, bp,
1376 		    "Synchronization request half-finished.");
1377 		bp->bio_cmd = BIO_WRITE;
1378 		bp->bio_cflags = 0;
1379 		cp = disk->d_consumer;
1380 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1381 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1382 		    cp->acr, cp->acw, cp->ace));
1383 		cp->index++;
1384 		g_io_request(bp, cp);
1385 		return;
1386 	}
1387 	case BIO_WRITE: {
1388 		off_t offset;
1389 		int i;
1390 
1391 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_sync_request_write,
1392 		    bp->bio_error);
1393 
1394 		if (bp->bio_error != 0) {
1395 			G_MIRROR_LOGREQ(0, bp,
1396 			    "Synchronization request failed (error=%d).",
1397 			    bp->bio_error);
1398 			g_mirror_sync_request_free(disk, bp);
1399 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
1400 			g_mirror_event_send(disk,
1401 			    G_MIRROR_DISK_STATE_DISCONNECTED,
1402 			    G_MIRROR_EVENT_DONTWAIT);
1403 			return;
1404 		}
1405 		G_MIRROR_LOGREQ(3, bp, "Synchronization request finished.");
1406 		if (sync->ds_offset >= sc->sc_mediasize ||
1407 		    sync->ds_consumer == NULL ||
1408 		    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1409 			/* Don't send more synchronization requests. */
1410 			sync->ds_inflight--;
1411 			g_mirror_sync_request_free(disk, bp);
1412 			if (sync->ds_inflight > 0)
1413 				return;
1414 			if (sync->ds_consumer == NULL ||
1415 			    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1416 				return;
1417 			}
1418 			/* Disk up-to-date, activate it. */
1419 			g_mirror_event_send(disk, G_MIRROR_DISK_STATE_ACTIVE,
1420 			    G_MIRROR_EVENT_DONTWAIT);
1421 			return;
1422 		}
1423 
1424 		/* Send next synchronization request. */
1425 		g_mirror_sync_reinit(disk, bp, sync->ds_offset);
1426 		sync->ds_offset += bp->bio_length;
1427 
1428 		G_MIRROR_LOGREQ(3, bp, "Sending synchronization request.");
1429 		sync->ds_consumer->index++;
1430 
1431 		/*
1432 		 * Delay the request if it is colliding with a regular request.
1433 		 */
1434 		if (g_mirror_regular_collision(sc, bp))
1435 			g_mirror_sync_delay(sc, bp);
1436 		else
1437 			g_io_request(bp, sync->ds_consumer);
1438 
1439 		/* Requeue delayed requests if possible. */
1440 		g_mirror_regular_release(sc);
1441 
1442 		/* Find the smallest offset */
1443 		offset = sc->sc_mediasize;
1444 		for (i = 0; i < g_mirror_syncreqs; i++) {
1445 			bp = sync->ds_bios[i];
1446 			if (bp != NULL && bp->bio_offset < offset)
1447 				offset = bp->bio_offset;
1448 		}
1449 		if (g_mirror_sync_period > 0 &&
1450 		    time_uptime - sync->ds_update_ts > g_mirror_sync_period) {
1451 			sync->ds_offset_done = offset;
1452 			g_mirror_update_metadata(disk);
1453 			sync->ds_update_ts = time_uptime;
1454 		}
1455 		return;
1456 	}
1457 	default:
1458 		panic("Invalid I/O request %p", bp);
1459 	}
1460 }
1461 
1462 static void
1463 g_mirror_request_prefer(struct g_mirror_softc *sc, struct bio *bp)
1464 {
1465 	struct g_mirror_disk *disk;
1466 	struct g_consumer *cp;
1467 	struct bio *cbp;
1468 
1469 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1470 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE)
1471 			break;
1472 	}
1473 	if (disk == NULL) {
1474 		if (bp->bio_error == 0)
1475 			bp->bio_error = ENXIO;
1476 		g_io_deliver(bp, bp->bio_error);
1477 		return;
1478 	}
1479 	cbp = g_clone_bio(bp);
1480 	if (cbp == NULL) {
1481 		if (bp->bio_error == 0)
1482 			bp->bio_error = ENOMEM;
1483 		g_io_deliver(bp, bp->bio_error);
1484 		return;
1485 	}
1486 	/*
1487 	 * Fill in the component buf structure.
1488 	 */
1489 	cp = disk->d_consumer;
1490 	cbp->bio_done = g_mirror_done;
1491 	cbp->bio_to = cp->provider;
1492 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1493 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1494 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1495 	    cp->acw, cp->ace));
1496 	cp->index++;
1497 	g_io_request(cbp, cp);
1498 }
1499 
1500 static void
1501 g_mirror_request_round_robin(struct g_mirror_softc *sc, struct bio *bp)
1502 {
1503 	struct g_mirror_disk *disk;
1504 	struct g_consumer *cp;
1505 	struct bio *cbp;
1506 
1507 	disk = g_mirror_get_disk(sc);
1508 	if (disk == NULL) {
1509 		if (bp->bio_error == 0)
1510 			bp->bio_error = ENXIO;
1511 		g_io_deliver(bp, bp->bio_error);
1512 		return;
1513 	}
1514 	cbp = g_clone_bio(bp);
1515 	if (cbp == NULL) {
1516 		if (bp->bio_error == 0)
1517 			bp->bio_error = ENOMEM;
1518 		g_io_deliver(bp, bp->bio_error);
1519 		return;
1520 	}
1521 	/*
1522 	 * Fill in the component buf structure.
1523 	 */
1524 	cp = disk->d_consumer;
1525 	cbp->bio_done = g_mirror_done;
1526 	cbp->bio_to = cp->provider;
1527 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1528 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1529 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1530 	    cp->acw, cp->ace));
1531 	cp->index++;
1532 	g_io_request(cbp, cp);
1533 }
1534 
1535 #define TRACK_SIZE  (1 * 1024 * 1024)
1536 #define LOAD_SCALE	256
1537 #define ABS(x)		(((x) >= 0) ? (x) : (-(x)))
1538 
1539 static void
1540 g_mirror_request_load(struct g_mirror_softc *sc, struct bio *bp)
1541 {
1542 	struct g_mirror_disk *disk, *dp;
1543 	struct g_consumer *cp;
1544 	struct bio *cbp;
1545 	int prio, best;
1546 
1547 	/* Find a disk with the smallest load. */
1548 	disk = NULL;
1549 	best = INT_MAX;
1550 	LIST_FOREACH(dp, &sc->sc_disks, d_next) {
1551 		if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1552 			continue;
1553 		prio = dp->load;
1554 		/* If disk head is precisely in position - highly prefer it. */
1555 		if (dp->d_last_offset == bp->bio_offset)
1556 			prio -= 2 * LOAD_SCALE;
1557 		else
1558 		/* If disk head is close to position - prefer it. */
1559 		if (ABS(dp->d_last_offset - bp->bio_offset) < TRACK_SIZE)
1560 			prio -= 1 * LOAD_SCALE;
1561 		if (prio <= best) {
1562 			disk = dp;
1563 			best = prio;
1564 		}
1565 	}
1566 	KASSERT(disk != NULL, ("NULL disk for %s.", sc->sc_name));
1567 	cbp = g_clone_bio(bp);
1568 	if (cbp == NULL) {
1569 		if (bp->bio_error == 0)
1570 			bp->bio_error = ENOMEM;
1571 		g_io_deliver(bp, bp->bio_error);
1572 		return;
1573 	}
1574 	/*
1575 	 * Fill in the component buf structure.
1576 	 */
1577 	cp = disk->d_consumer;
1578 	cbp->bio_done = g_mirror_done;
1579 	cbp->bio_to = cp->provider;
1580 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1581 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1582 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1583 	    cp->acw, cp->ace));
1584 	cp->index++;
1585 	/* Remember last head position */
1586 	disk->d_last_offset = bp->bio_offset + bp->bio_length;
1587 	/* Update loads. */
1588 	LIST_FOREACH(dp, &sc->sc_disks, d_next) {
1589 		dp->load = (dp->d_consumer->index * LOAD_SCALE +
1590 		    dp->load * 7) / 8;
1591 	}
1592 	g_io_request(cbp, cp);
1593 }
1594 
1595 static void
1596 g_mirror_request_split(struct g_mirror_softc *sc, struct bio *bp)
1597 {
1598 	struct bio_queue queue;
1599 	struct g_mirror_disk *disk;
1600 	struct g_consumer *cp;
1601 	struct bio *cbp;
1602 	off_t left, mod, offset, slice;
1603 	u_char *data;
1604 	u_int ndisks;
1605 
1606 	if (bp->bio_length <= sc->sc_slice) {
1607 		g_mirror_request_round_robin(sc, bp);
1608 		return;
1609 	}
1610 	ndisks = g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE);
1611 	slice = bp->bio_length / ndisks;
1612 	mod = slice % sc->sc_provider->sectorsize;
1613 	if (mod != 0)
1614 		slice += sc->sc_provider->sectorsize - mod;
1615 	/*
1616 	 * Allocate all bios before sending any request, so we can
1617 	 * return ENOMEM in nice and clean way.
1618 	 */
1619 	left = bp->bio_length;
1620 	offset = bp->bio_offset;
1621 	data = bp->bio_data;
1622 	TAILQ_INIT(&queue);
1623 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1624 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1625 			continue;
1626 		cbp = g_clone_bio(bp);
1627 		if (cbp == NULL) {
1628 			while ((cbp = TAILQ_FIRST(&queue)) != NULL) {
1629 				TAILQ_REMOVE(&queue, cbp, bio_queue);
1630 				g_destroy_bio(cbp);
1631 			}
1632 			if (bp->bio_error == 0)
1633 				bp->bio_error = ENOMEM;
1634 			g_io_deliver(bp, bp->bio_error);
1635 			return;
1636 		}
1637 		TAILQ_INSERT_TAIL(&queue, cbp, bio_queue);
1638 		cbp->bio_done = g_mirror_done;
1639 		cbp->bio_caller1 = disk;
1640 		cbp->bio_to = disk->d_consumer->provider;
1641 		cbp->bio_offset = offset;
1642 		cbp->bio_data = data;
1643 		cbp->bio_length = MIN(left, slice);
1644 		left -= cbp->bio_length;
1645 		if (left == 0)
1646 			break;
1647 		offset += cbp->bio_length;
1648 		data += cbp->bio_length;
1649 	}
1650 	while ((cbp = TAILQ_FIRST(&queue)) != NULL) {
1651 		TAILQ_REMOVE(&queue, cbp, bio_queue);
1652 		G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1653 		disk = cbp->bio_caller1;
1654 		cbp->bio_caller1 = NULL;
1655 		cp = disk->d_consumer;
1656 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1657 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1658 		    cp->acr, cp->acw, cp->ace));
1659 		disk->d_consumer->index++;
1660 		g_io_request(cbp, disk->d_consumer);
1661 	}
1662 }
1663 
1664 static void
1665 g_mirror_register_request(struct g_mirror_softc *sc, struct bio *bp)
1666 {
1667 	struct bio_queue queue;
1668 	struct bio *cbp;
1669 	struct g_consumer *cp;
1670 	struct g_mirror_disk *disk;
1671 
1672 	sx_assert(&sc->sc_lock, SA_XLOCKED);
1673 
1674 	/*
1675 	 * To avoid ordering issues, if a write is deferred because of a
1676 	 * collision with a sync request, all I/O is deferred until that
1677 	 * write is initiated.
1678 	 */
1679 	if (bp->bio_from->geom != sc->sc_sync.ds_geom &&
1680 	    !TAILQ_EMPTY(&sc->sc_regular_delayed)) {
1681 		g_mirror_regular_delay(sc, bp);
1682 		return;
1683 	}
1684 
1685 	switch (bp->bio_cmd) {
1686 	case BIO_READ:
1687 		switch (sc->sc_balance) {
1688 		case G_MIRROR_BALANCE_LOAD:
1689 			g_mirror_request_load(sc, bp);
1690 			break;
1691 		case G_MIRROR_BALANCE_PREFER:
1692 			g_mirror_request_prefer(sc, bp);
1693 			break;
1694 		case G_MIRROR_BALANCE_ROUND_ROBIN:
1695 			g_mirror_request_round_robin(sc, bp);
1696 			break;
1697 		case G_MIRROR_BALANCE_SPLIT:
1698 			g_mirror_request_split(sc, bp);
1699 			break;
1700 		}
1701 		return;
1702 	case BIO_WRITE:
1703 	case BIO_DELETE:
1704 		/*
1705 		 * Delay the request if it is colliding with a synchronization
1706 		 * request.
1707 		 */
1708 		if (g_mirror_sync_collision(sc, bp)) {
1709 			g_mirror_regular_delay(sc, bp);
1710 			return;
1711 		}
1712 
1713 		if (sc->sc_idle)
1714 			g_mirror_unidle(sc);
1715 		else
1716 			sc->sc_last_write = time_uptime;
1717 
1718 		/*
1719 		 * Bump syncid on first write.
1720 		 */
1721 		if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0) {
1722 			sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
1723 			g_mirror_bump_syncid(sc);
1724 		}
1725 
1726 		/*
1727 		 * Allocate all bios before sending any request, so we can
1728 		 * return ENOMEM in nice and clean way.
1729 		 */
1730 		TAILQ_INIT(&queue);
1731 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1732 			switch (disk->d_state) {
1733 			case G_MIRROR_DISK_STATE_ACTIVE:
1734 				break;
1735 			case G_MIRROR_DISK_STATE_SYNCHRONIZING:
1736 				if (bp->bio_offset >= disk->d_sync.ds_offset)
1737 					continue;
1738 				break;
1739 			default:
1740 				continue;
1741 			}
1742 			if (bp->bio_cmd == BIO_DELETE &&
1743 			    (disk->d_flags & G_MIRROR_DISK_FLAG_CANDELETE) == 0)
1744 				continue;
1745 			cbp = g_clone_bio(bp);
1746 			if (cbp == NULL) {
1747 				while ((cbp = TAILQ_FIRST(&queue)) != NULL) {
1748 					TAILQ_REMOVE(&queue, cbp, bio_queue);
1749 					g_destroy_bio(cbp);
1750 				}
1751 				if (bp->bio_error == 0)
1752 					bp->bio_error = ENOMEM;
1753 				g_io_deliver(bp, bp->bio_error);
1754 				return;
1755 			}
1756 			TAILQ_INSERT_TAIL(&queue, cbp, bio_queue);
1757 			cbp->bio_done = g_mirror_done;
1758 			cp = disk->d_consumer;
1759 			cbp->bio_caller1 = cp;
1760 			cbp->bio_to = cp->provider;
1761 			KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1762 			    ("Consumer %s not opened (r%dw%de%d).",
1763 			    cp->provider->name, cp->acr, cp->acw, cp->ace));
1764 		}
1765 		if (TAILQ_EMPTY(&queue)) {
1766 			KASSERT(bp->bio_cmd == BIO_DELETE,
1767 			    ("No consumers for regular request %p", bp));
1768 			g_io_deliver(bp, EOPNOTSUPP);
1769 			return;
1770 		}
1771 		while ((cbp = TAILQ_FIRST(&queue)) != NULL) {
1772 			G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1773 			TAILQ_REMOVE(&queue, cbp, bio_queue);
1774 			cp = cbp->bio_caller1;
1775 			cbp->bio_caller1 = NULL;
1776 			cp->index++;
1777 			sc->sc_writes++;
1778 			g_io_request(cbp, cp);
1779 		}
1780 		/*
1781 		 * Put request onto inflight queue, so we can check if new
1782 		 * synchronization requests don't collide with it.
1783 		 */
1784 		TAILQ_INSERT_TAIL(&sc->sc_inflight, bp, bio_queue);
1785 		return;
1786 	case BIO_FLUSH:
1787 		TAILQ_INIT(&queue);
1788 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1789 			if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1790 				continue;
1791 			cbp = g_clone_bio(bp);
1792 			if (cbp == NULL) {
1793 				while ((cbp = TAILQ_FIRST(&queue)) != NULL) {
1794 					TAILQ_REMOVE(&queue, cbp, bio_queue);
1795 					g_destroy_bio(cbp);
1796 				}
1797 				if (bp->bio_error == 0)
1798 					bp->bio_error = ENOMEM;
1799 				g_io_deliver(bp, bp->bio_error);
1800 				return;
1801 			}
1802 			TAILQ_INSERT_TAIL(&queue, cbp, bio_queue);
1803 			cbp->bio_done = g_mirror_done;
1804 			cbp->bio_caller1 = disk;
1805 			cbp->bio_to = disk->d_consumer->provider;
1806 		}
1807 		KASSERT(!TAILQ_EMPTY(&queue),
1808 		    ("No consumers for regular request %p", bp));
1809 		while ((cbp = TAILQ_FIRST(&queue)) != NULL) {
1810 			G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1811 			TAILQ_REMOVE(&queue, cbp, bio_queue);
1812 			disk = cbp->bio_caller1;
1813 			cbp->bio_caller1 = NULL;
1814 			cp = disk->d_consumer;
1815 			KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1816 			    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1817 			    cp->acr, cp->acw, cp->ace));
1818 			cp->index++;
1819 			g_io_request(cbp, cp);
1820 		}
1821 		break;
1822 	default:
1823 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1824 		    bp->bio_cmd, sc->sc_name));
1825 		break;
1826 	}
1827 }
1828 
1829 static int
1830 g_mirror_can_destroy(struct g_mirror_softc *sc)
1831 {
1832 	struct g_geom *gp;
1833 	struct g_consumer *cp;
1834 
1835 	g_topology_assert();
1836 	gp = sc->sc_geom;
1837 	if (gp->softc == NULL)
1838 		return (1);
1839 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_TASTING) != 0)
1840 		return (0);
1841 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1842 		if (g_mirror_is_busy(sc, cp))
1843 			return (0);
1844 	}
1845 	gp = sc->sc_sync.ds_geom;
1846 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1847 		if (g_mirror_is_busy(sc, cp))
1848 			return (0);
1849 	}
1850 	G_MIRROR_DEBUG(2, "No I/O requests for %s, it can be destroyed.",
1851 	    sc->sc_name);
1852 	return (1);
1853 }
1854 
1855 static int
1856 g_mirror_try_destroy(struct g_mirror_softc *sc)
1857 {
1858 
1859 	if (sc->sc_rootmount != NULL) {
1860 		G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p", __LINE__,
1861 		    sc->sc_rootmount);
1862 		root_mount_rel(sc->sc_rootmount);
1863 		sc->sc_rootmount = NULL;
1864 	}
1865 	g_topology_lock();
1866 	if (!g_mirror_can_destroy(sc)) {
1867 		g_topology_unlock();
1868 		return (0);
1869 	}
1870 	sc->sc_geom->softc = NULL;
1871 	sc->sc_sync.ds_geom->softc = NULL;
1872 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DRAIN) != 0) {
1873 		g_topology_unlock();
1874 		G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1875 		    &sc->sc_worker);
1876 		/* Unlock sc_lock here, as it can be destroyed after wakeup. */
1877 		sx_xunlock(&sc->sc_lock);
1878 		wakeup(&sc->sc_worker);
1879 		sc->sc_worker = NULL;
1880 	} else {
1881 		g_topology_unlock();
1882 		g_mirror_destroy_device(sc);
1883 	}
1884 	return (1);
1885 }
1886 
1887 /*
1888  * Worker thread.
1889  */
1890 static void
1891 g_mirror_worker(void *arg)
1892 {
1893 	struct g_mirror_softc *sc;
1894 	struct g_mirror_event *ep;
1895 	struct bio *bp;
1896 	int timeout;
1897 
1898 	sc = arg;
1899 	thread_lock(curthread);
1900 	sched_prio(curthread, PRIBIO);
1901 	thread_unlock(curthread);
1902 
1903 	sx_xlock(&sc->sc_lock);
1904 	for (;;) {
1905 		G_MIRROR_DEBUG(5, "%s: Let's see...", __func__);
1906 		/*
1907 		 * First take a look at events.
1908 		 * This is important to handle events before any I/O requests.
1909 		 */
1910 		ep = g_mirror_event_first(sc);
1911 		if (ep != NULL) {
1912 			g_mirror_event_remove(sc, ep);
1913 			if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0) {
1914 				/* Update only device status. */
1915 				G_MIRROR_DEBUG(3,
1916 				    "Running event for device %s.",
1917 				    sc->sc_name);
1918 				ep->e_error = 0;
1919 				g_mirror_update_device(sc, true);
1920 			} else {
1921 				/* Update disk status. */
1922 				G_MIRROR_DEBUG(3, "Running event for disk %s.",
1923 				     g_mirror_get_diskname(ep->e_disk));
1924 				ep->e_error = g_mirror_update_disk(ep->e_disk,
1925 				    ep->e_state);
1926 				if (ep->e_error == 0)
1927 					g_mirror_update_device(sc, false);
1928 			}
1929 			if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0) {
1930 				KASSERT(ep->e_error == 0,
1931 				    ("Error cannot be handled."));
1932 				g_mirror_event_free(ep);
1933 			} else {
1934 				ep->e_flags |= G_MIRROR_EVENT_DONE;
1935 				G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1936 				    ep);
1937 				mtx_lock(&sc->sc_events_mtx);
1938 				wakeup(ep);
1939 				mtx_unlock(&sc->sc_events_mtx);
1940 			}
1941 			if ((sc->sc_flags &
1942 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1943 				if (g_mirror_try_destroy(sc)) {
1944 					curthread->td_pflags &= ~TDP_GEOM;
1945 					G_MIRROR_DEBUG(1, "Thread exiting.");
1946 					kproc_exit(0);
1947 				}
1948 			}
1949 			G_MIRROR_DEBUG(5, "%s: I'm here 1.", __func__);
1950 			continue;
1951 		}
1952 
1953 		/*
1954 		 * Check if we can mark array as CLEAN and if we can't take
1955 		 * how much seconds should we wait.
1956 		 */
1957 		timeout = g_mirror_idle(sc, -1);
1958 
1959 		/*
1960 		 * Handle I/O requests.
1961 		 */
1962 		mtx_lock(&sc->sc_queue_mtx);
1963 		bp = TAILQ_FIRST(&sc->sc_queue);
1964 		if (bp != NULL)
1965 			TAILQ_REMOVE(&sc->sc_queue, bp, bio_queue);
1966 		else {
1967 			if ((sc->sc_flags &
1968 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1969 				mtx_unlock(&sc->sc_queue_mtx);
1970 				if (g_mirror_try_destroy(sc)) {
1971 					curthread->td_pflags &= ~TDP_GEOM;
1972 					G_MIRROR_DEBUG(1, "Thread exiting.");
1973 					kproc_exit(0);
1974 				}
1975 				mtx_lock(&sc->sc_queue_mtx);
1976 				if (!TAILQ_EMPTY(&sc->sc_queue)) {
1977 					mtx_unlock(&sc->sc_queue_mtx);
1978 					continue;
1979 				}
1980 			}
1981 			if (g_mirror_event_first(sc) != NULL) {
1982 				mtx_unlock(&sc->sc_queue_mtx);
1983 				continue;
1984 			}
1985 			sx_xunlock(&sc->sc_lock);
1986 			MSLEEP(sc, &sc->sc_queue_mtx, PRIBIO | PDROP, "m:w1",
1987 			    timeout * hz);
1988 			sx_xlock(&sc->sc_lock);
1989 			G_MIRROR_DEBUG(5, "%s: I'm here 4.", __func__);
1990 			continue;
1991 		}
1992 		mtx_unlock(&sc->sc_queue_mtx);
1993 
1994 		if (bp->bio_from->geom == sc->sc_sync.ds_geom &&
1995 		    (bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0) {
1996 			/*
1997 			 * Handle completion of the first half (the read) of a
1998 			 * block synchronization operation.
1999 			 */
2000 			g_mirror_sync_request(sc, bp);
2001 		} else if (bp->bio_to != sc->sc_provider) {
2002 			if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_REGULAR) != 0)
2003 				/*
2004 				 * Handle completion of a regular I/O request.
2005 				 */
2006 				g_mirror_regular_request(sc, bp);
2007 			else if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0)
2008 				/*
2009 				 * Handle completion of the second half (the
2010 				 * write) of a block synchronization operation.
2011 				 */
2012 				g_mirror_sync_request(sc, bp);
2013 			else {
2014 				KASSERT(0,
2015 				    ("Invalid request cflags=0x%hx to=%s.",
2016 				    bp->bio_cflags, bp->bio_to->name));
2017 			}
2018 		} else {
2019 			/*
2020 			 * Initiate an I/O request.
2021 			 */
2022 			g_mirror_register_request(sc, bp);
2023 		}
2024 		G_MIRROR_DEBUG(5, "%s: I'm here 9.", __func__);
2025 	}
2026 }
2027 
2028 static void
2029 g_mirror_update_idle(struct g_mirror_softc *sc, struct g_mirror_disk *disk)
2030 {
2031 
2032 	sx_assert(&sc->sc_lock, SX_LOCKED);
2033 
2034 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
2035 		return;
2036 	if (!sc->sc_idle && (disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) == 0) {
2037 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as dirty.",
2038 		    g_mirror_get_diskname(disk), sc->sc_name);
2039 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
2040 	} else if (sc->sc_idle &&
2041 	    (disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
2042 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as clean.",
2043 		    g_mirror_get_diskname(disk), sc->sc_name);
2044 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2045 	}
2046 }
2047 
2048 static void
2049 g_mirror_sync_reinit(const struct g_mirror_disk *disk, struct bio *bp,
2050     off_t offset)
2051 {
2052 	void *data;
2053 	int idx;
2054 
2055 	data = bp->bio_data;
2056 	idx = (int)(uintptr_t)bp->bio_caller1;
2057 	g_reset_bio(bp);
2058 
2059 	bp->bio_cmd = BIO_READ;
2060 	bp->bio_data = data;
2061 	bp->bio_done = g_mirror_sync_done;
2062 	bp->bio_from = disk->d_sync.ds_consumer;
2063 	bp->bio_to = disk->d_softc->sc_provider;
2064 	bp->bio_caller1 = (void *)(uintptr_t)idx;
2065 	bp->bio_offset = offset;
2066 	bp->bio_length = MIN(MAXPHYS,
2067 	    disk->d_softc->sc_mediasize - bp->bio_offset);
2068 }
2069 
2070 static void
2071 g_mirror_sync_start(struct g_mirror_disk *disk)
2072 {
2073 	struct g_mirror_softc *sc;
2074 	struct g_mirror_disk_sync *sync;
2075 	struct g_consumer *cp;
2076 	struct bio *bp;
2077 	int error, i;
2078 
2079 	g_topology_assert_not();
2080 	sc = disk->d_softc;
2081 	sync = &disk->d_sync;
2082 	sx_assert(&sc->sc_lock, SX_LOCKED);
2083 
2084 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2085 	    ("Disk %s is not marked for synchronization.",
2086 	    g_mirror_get_diskname(disk)));
2087 	KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2088 	    ("Device not in RUNNING state (%s, %u).", sc->sc_name,
2089 	    sc->sc_state));
2090 
2091 	sx_xunlock(&sc->sc_lock);
2092 	g_topology_lock();
2093 	cp = g_new_consumer(sc->sc_sync.ds_geom);
2094 	cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
2095 	error = g_attach(cp, sc->sc_provider);
2096 	KASSERT(error == 0,
2097 	    ("Cannot attach to %s (error=%d).", sc->sc_name, error));
2098 	error = g_access(cp, 1, 0, 0);
2099 	KASSERT(error == 0, ("Cannot open %s (error=%d).", sc->sc_name, error));
2100 	g_topology_unlock();
2101 	sx_xlock(&sc->sc_lock);
2102 
2103 	G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s.", sc->sc_name,
2104 	    g_mirror_get_diskname(disk));
2105 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) == 0)
2106 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
2107 	KASSERT(sync->ds_consumer == NULL,
2108 	    ("Sync consumer already exists (device=%s, disk=%s).",
2109 	    sc->sc_name, g_mirror_get_diskname(disk)));
2110 
2111 	sync->ds_consumer = cp;
2112 	sync->ds_consumer->private = disk;
2113 	sync->ds_consumer->index = 0;
2114 
2115 	/*
2116 	 * Allocate memory for synchronization bios and initialize them.
2117 	 */
2118 	sync->ds_bios = malloc(sizeof(struct bio *) * g_mirror_syncreqs,
2119 	    M_MIRROR, M_WAITOK);
2120 	for (i = 0; i < g_mirror_syncreqs; i++) {
2121 		bp = g_alloc_bio();
2122 		sync->ds_bios[i] = bp;
2123 
2124 		bp->bio_data = malloc(MAXPHYS, M_MIRROR, M_WAITOK);
2125 		bp->bio_caller1 = (void *)(uintptr_t)i;
2126 		g_mirror_sync_reinit(disk, bp, sync->ds_offset);
2127 		sync->ds_offset += bp->bio_length;
2128 	}
2129 
2130 	/* Increase the number of disks in SYNCHRONIZING state. */
2131 	sc->sc_sync.ds_ndisks++;
2132 	/* Set the number of in-flight synchronization requests. */
2133 	sync->ds_inflight = g_mirror_syncreqs;
2134 
2135 	/*
2136 	 * Fire off first synchronization requests.
2137 	 */
2138 	for (i = 0; i < g_mirror_syncreqs; i++) {
2139 		bp = sync->ds_bios[i];
2140 		G_MIRROR_LOGREQ(3, bp, "Sending synchronization request.");
2141 		sync->ds_consumer->index++;
2142 		/*
2143 		 * Delay the request if it is colliding with a regular request.
2144 		 */
2145 		if (g_mirror_regular_collision(sc, bp))
2146 			g_mirror_sync_delay(sc, bp);
2147 		else
2148 			g_io_request(bp, sync->ds_consumer);
2149 	}
2150 }
2151 
2152 /*
2153  * Stop synchronization process.
2154  * type: 0 - synchronization finished
2155  *       1 - synchronization stopped
2156  */
2157 static void
2158 g_mirror_sync_stop(struct g_mirror_disk *disk, int type)
2159 {
2160 	struct g_mirror_softc *sc;
2161 	struct g_consumer *cp;
2162 
2163 	g_topology_assert_not();
2164 	sc = disk->d_softc;
2165 	sx_assert(&sc->sc_lock, SX_LOCKED);
2166 
2167 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2168 	    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2169 	    g_mirror_disk_state2str(disk->d_state)));
2170 	if (disk->d_sync.ds_consumer == NULL)
2171 		return;
2172 
2173 	if (type == 0) {
2174 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s finished.",
2175 		    sc->sc_name, g_mirror_get_diskname(disk));
2176 	} else /* if (type == 1) */ {
2177 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s stopped.",
2178 		    sc->sc_name, g_mirror_get_diskname(disk));
2179 	}
2180 	g_mirror_regular_release(sc);
2181 	free(disk->d_sync.ds_bios, M_MIRROR);
2182 	disk->d_sync.ds_bios = NULL;
2183 	cp = disk->d_sync.ds_consumer;
2184 	disk->d_sync.ds_consumer = NULL;
2185 	disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2186 	sc->sc_sync.ds_ndisks--;
2187 	sx_xunlock(&sc->sc_lock); /* Avoid recursion on sc_lock. */
2188 	g_topology_lock();
2189 	g_mirror_kill_consumer(sc, cp);
2190 	g_topology_unlock();
2191 	sx_xlock(&sc->sc_lock);
2192 }
2193 
2194 static void
2195 g_mirror_launch_provider(struct g_mirror_softc *sc)
2196 {
2197 	struct g_mirror_disk *disk;
2198 	struct g_provider *pp, *dp;
2199 
2200 	sx_assert(&sc->sc_lock, SX_LOCKED);
2201 
2202 	g_topology_lock();
2203 	pp = g_new_providerf(sc->sc_geom, "mirror/%s", sc->sc_name);
2204 	pp->flags |= G_PF_DIRECT_RECEIVE;
2205 	pp->mediasize = sc->sc_mediasize;
2206 	pp->sectorsize = sc->sc_sectorsize;
2207 	pp->stripesize = 0;
2208 	pp->stripeoffset = 0;
2209 
2210 	/* Splitting of unmapped BIO's could work but isn't implemented now */
2211 	if (sc->sc_balance != G_MIRROR_BALANCE_SPLIT)
2212 		pp->flags |= G_PF_ACCEPT_UNMAPPED;
2213 
2214 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2215 		if (disk->d_consumer && disk->d_consumer->provider) {
2216 			dp = disk->d_consumer->provider;
2217 			if (dp->stripesize > pp->stripesize) {
2218 				pp->stripesize = dp->stripesize;
2219 				pp->stripeoffset = dp->stripeoffset;
2220 			}
2221 			/* A provider underneath us doesn't support unmapped */
2222 			if ((dp->flags & G_PF_ACCEPT_UNMAPPED) == 0) {
2223 				G_MIRROR_DEBUG(0, "Cancelling unmapped "
2224 				    "because of %s.", dp->name);
2225 				pp->flags &= ~G_PF_ACCEPT_UNMAPPED;
2226 			}
2227 		}
2228 	}
2229 	pp->private = sc;
2230 	sc->sc_refcnt++;
2231 	sc->sc_provider = pp;
2232 	g_error_provider(pp, 0);
2233 	g_topology_unlock();
2234 	G_MIRROR_DEBUG(0, "Device %s launched (%u/%u).", pp->name,
2235 	    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE), sc->sc_ndisks);
2236 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2237 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
2238 			g_mirror_sync_start(disk);
2239 	}
2240 }
2241 
2242 static void
2243 g_mirror_destroy_provider(struct g_mirror_softc *sc)
2244 {
2245 	struct g_mirror_disk *disk;
2246 	struct bio *bp;
2247 
2248 	g_topology_assert_not();
2249 	KASSERT(sc->sc_provider != NULL, ("NULL provider (device=%s).",
2250 	    sc->sc_name));
2251 
2252 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2253 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
2254 			g_mirror_sync_stop(disk, 1);
2255 	}
2256 
2257 	g_topology_lock();
2258 	g_error_provider(sc->sc_provider, ENXIO);
2259 	mtx_lock(&sc->sc_queue_mtx);
2260 	while ((bp = TAILQ_FIRST(&sc->sc_queue)) != NULL) {
2261 		TAILQ_REMOVE(&sc->sc_queue, bp, bio_queue);
2262 		/*
2263 		 * Abort any pending I/O that wasn't generated by us.
2264 		 * Synchronization requests and requests destined for individual
2265 		 * mirror components can be destroyed immediately.
2266 		 */
2267 		if (bp->bio_to == sc->sc_provider &&
2268 		    bp->bio_from->geom != sc->sc_sync.ds_geom) {
2269 			g_io_deliver(bp, ENXIO);
2270 		} else {
2271 			if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0)
2272 				free(bp->bio_data, M_MIRROR);
2273 			g_destroy_bio(bp);
2274 		}
2275 	}
2276 	mtx_unlock(&sc->sc_queue_mtx);
2277 	g_wither_provider(sc->sc_provider, ENXIO);
2278 	sc->sc_provider = NULL;
2279 	G_MIRROR_DEBUG(0, "Device %s: provider destroyed.", sc->sc_name);
2280 	g_topology_unlock();
2281 }
2282 
2283 static void
2284 g_mirror_go(void *arg)
2285 {
2286 	struct g_mirror_softc *sc;
2287 
2288 	sc = arg;
2289 	G_MIRROR_DEBUG(0, "Force device %s start due to timeout.", sc->sc_name);
2290 	g_mirror_event_send(sc, 0,
2291 	    G_MIRROR_EVENT_DONTWAIT | G_MIRROR_EVENT_DEVICE);
2292 }
2293 
2294 static u_int
2295 g_mirror_determine_state(struct g_mirror_disk *disk)
2296 {
2297 	struct g_mirror_softc *sc;
2298 	u_int state;
2299 
2300 	sc = disk->d_softc;
2301 	if (sc->sc_syncid == disk->d_sync.ds_syncid) {
2302 		if ((disk->d_flags &
2303 		    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0 &&
2304 		    (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 0 ||
2305 		     (disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) == 0)) {
2306 			/* Disk does not need synchronization. */
2307 			state = G_MIRROR_DISK_STATE_ACTIVE;
2308 		} else {
2309 			if ((sc->sc_flags &
2310 			     G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
2311 			    (disk->d_flags &
2312 			     G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
2313 				/*
2314 				 * We can start synchronization from
2315 				 * the stored offset.
2316 				 */
2317 				state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
2318 			} else {
2319 				state = G_MIRROR_DISK_STATE_STALE;
2320 			}
2321 		}
2322 	} else if (disk->d_sync.ds_syncid < sc->sc_syncid) {
2323 		/*
2324 		 * Reset all synchronization data for this disk,
2325 		 * because if it even was synchronized, it was
2326 		 * synchronized to disks with different syncid.
2327 		 */
2328 		disk->d_flags |= G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2329 		disk->d_sync.ds_offset = 0;
2330 		disk->d_sync.ds_offset_done = 0;
2331 		disk->d_sync.ds_syncid = sc->sc_syncid;
2332 		if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
2333 		    (disk->d_flags & G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
2334 			state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
2335 		} else {
2336 			state = G_MIRROR_DISK_STATE_STALE;
2337 		}
2338 	} else /* if (sc->sc_syncid < disk->d_sync.ds_syncid) */ {
2339 		/*
2340 		 * Not good, NOT GOOD!
2341 		 * It means that mirror was started on stale disks
2342 		 * and more fresh disk just arrive.
2343 		 * If there were writes, mirror is broken, sorry.
2344 		 * I think the best choice here is don't touch
2345 		 * this disk and inform the user loudly.
2346 		 */
2347 		G_MIRROR_DEBUG(0, "Device %s was started before the freshest "
2348 		    "disk (%s) arrives!! It will not be connected to the "
2349 		    "running device.", sc->sc_name,
2350 		    g_mirror_get_diskname(disk));
2351 		g_mirror_destroy_disk(disk);
2352 		state = G_MIRROR_DISK_STATE_NONE;
2353 		/* Return immediately, because disk was destroyed. */
2354 		return (state);
2355 	}
2356 	G_MIRROR_DEBUG(3, "State for %s disk: %s.",
2357 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(state));
2358 	return (state);
2359 }
2360 
2361 /*
2362  * Update device state.
2363  */
2364 static void
2365 g_mirror_update_device(struct g_mirror_softc *sc, bool force)
2366 {
2367 	struct g_mirror_disk *disk;
2368 	u_int state;
2369 
2370 	sx_assert(&sc->sc_lock, SX_XLOCKED);
2371 
2372 	switch (sc->sc_state) {
2373 	case G_MIRROR_DEVICE_STATE_STARTING:
2374 	    {
2375 		struct g_mirror_disk *pdisk, *tdisk;
2376 		const char *mismatch;
2377 		uintmax_t found, newest;
2378 		u_int dirty, ndisks;
2379 
2380 		/* Pre-flight checks */
2381 		LIST_FOREACH_SAFE(disk, &sc->sc_disks, d_next, tdisk) {
2382 			/*
2383 			 * Confirm we already detected the newest genid.
2384 			 */
2385 			KASSERT(sc->sc_genid >= disk->d_genid,
2386 			    ("%s: found newer genid %u (sc:%p had %u).", __func__,
2387 			    disk->d_genid, sc, sc->sc_genid));
2388 
2389 			/* Kick out any previously tasted stale components. */
2390 			if (disk->d_genid < sc->sc_genid) {
2391 				G_MIRROR_DEBUG(0, "Stale 'genid' field on %s "
2392 				    "(device %s) (component=%u latest=%u), skipping.",
2393 				    g_mirror_get_diskname(disk), sc->sc_name,
2394 				    disk->d_genid, sc->sc_genid);
2395 				g_mirror_destroy_disk(disk);
2396 				sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2397 				continue;
2398 			}
2399 
2400 			/*
2401 			 * Confirm we already detected the newest syncid.
2402 			 */
2403 			KASSERT(sc->sc_syncid >= disk->d_sync.ds_syncid,
2404 			    ("%s: found newer syncid %u (sc:%p had %u).",
2405 			     __func__, disk->d_sync.ds_syncid, sc,
2406 			     sc->sc_syncid));
2407 
2408 #define DETECT_MISMATCH(field, name) \
2409 			if (mismatch == NULL &&					\
2410 			    disk->d_init_ ## field != sc->sc_ ## field) {	\
2411 				mismatch = name;				\
2412 				found = (intmax_t)disk->d_init_ ## field;	\
2413 				newest = (intmax_t)sc->sc_ ## field;		\
2414 			}
2415 			mismatch = NULL;
2416 			DETECT_MISMATCH(ndisks, "md_all");
2417 			DETECT_MISMATCH(balance, "md_balance");
2418 			DETECT_MISMATCH(slice, "md_slice");
2419 			DETECT_MISMATCH(mediasize, "md_mediasize");
2420 #undef DETECT_MISMATCH
2421 			if (mismatch != NULL) {
2422 				G_MIRROR_DEBUG(0, "Found a mismatching '%s' "
2423 				    "field on %s (device %s) (found=%ju "
2424 				    "newest=%ju).", mismatch,
2425 				    g_mirror_get_diskname(disk), sc->sc_name,
2426 				    found, newest);
2427 				g_mirror_destroy_disk(disk);
2428 				sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2429 				continue;
2430 			}
2431 		}
2432 
2433 		KASSERT(sc->sc_provider == NULL,
2434 		    ("Non-NULL provider in STARTING state (%s).", sc->sc_name));
2435 		/*
2436 		 * Are we ready? If the timeout (force is true) has expired, and
2437 		 * any disks are present, then yes. If we're permitted to launch
2438 		 * before the timeout has expired and the expected number of
2439 		 * current-generation mirror disks have been tasted, then yes.
2440 		 */
2441 		ndisks = g_mirror_ndisks(sc, -1);
2442 		if ((force && ndisks > 0) ||
2443 		    (g_launch_mirror_before_timeout && ndisks == sc->sc_ndisks)) {
2444 			;
2445 		} else if (ndisks == 0) {
2446 			/*
2447 			 * Disks went down in starting phase, so destroy
2448 			 * device.
2449 			 */
2450 			callout_drain(&sc->sc_callout);
2451 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2452 			G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p", __LINE__,
2453 			    sc->sc_rootmount);
2454 			root_mount_rel(sc->sc_rootmount);
2455 			sc->sc_rootmount = NULL;
2456 			return;
2457 		} else {
2458 			return;
2459 		}
2460 
2461 		/*
2462 		 * Activate all disks with the biggest syncid.
2463 		 */
2464 		if (force) {
2465 			/*
2466 			 * If 'force' is true, we have been called due to
2467 			 * timeout, so don't bother canceling timeout.
2468 			 */
2469 			ndisks = 0;
2470 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2471 				if ((disk->d_flags &
2472 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
2473 					ndisks++;
2474 				}
2475 			}
2476 			if (ndisks == 0) {
2477 				/* No valid disks found, destroy device. */
2478 				sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2479 				G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p",
2480 				    __LINE__, sc->sc_rootmount);
2481 				root_mount_rel(sc->sc_rootmount);
2482 				sc->sc_rootmount = NULL;
2483 				return;
2484 			}
2485 		} else {
2486 			/* Cancel timeout. */
2487 			callout_drain(&sc->sc_callout);
2488 		}
2489 
2490 		/*
2491 		 * Here we need to look for dirty disks and if all disks
2492 		 * with the biggest syncid are dirty, we have to choose
2493 		 * one with the biggest priority and rebuild the rest.
2494 		 */
2495 		/*
2496 		 * Find the number of dirty disks with the biggest syncid.
2497 		 * Find the number of disks with the biggest syncid.
2498 		 * While here, find a disk with the biggest priority.
2499 		 */
2500 		dirty = ndisks = 0;
2501 		pdisk = NULL;
2502 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2503 			if (disk->d_sync.ds_syncid != sc->sc_syncid)
2504 				continue;
2505 			if ((disk->d_flags &
2506 			    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2507 				continue;
2508 			}
2509 			ndisks++;
2510 			if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
2511 				dirty++;
2512 				if (pdisk == NULL ||
2513 				    pdisk->d_priority < disk->d_priority) {
2514 					pdisk = disk;
2515 				}
2516 			}
2517 		}
2518 		if (dirty == 0) {
2519 			/* No dirty disks at all, great. */
2520 		} else if (dirty == ndisks) {
2521 			/*
2522 			 * Force synchronization for all dirty disks except one
2523 			 * with the biggest priority.
2524 			 */
2525 			KASSERT(pdisk != NULL, ("pdisk == NULL"));
2526 			G_MIRROR_DEBUG(1, "Using disk %s (device %s) as a "
2527 			    "master disk for synchronization.",
2528 			    g_mirror_get_diskname(pdisk), sc->sc_name);
2529 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2530 				if (disk->d_sync.ds_syncid != sc->sc_syncid)
2531 					continue;
2532 				if ((disk->d_flags &
2533 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2534 					continue;
2535 				}
2536 				KASSERT((disk->d_flags &
2537 				    G_MIRROR_DISK_FLAG_DIRTY) != 0,
2538 				    ("Disk %s isn't marked as dirty.",
2539 				    g_mirror_get_diskname(disk)));
2540 				/* Skip the disk with the biggest priority. */
2541 				if (disk == pdisk)
2542 					continue;
2543 				disk->d_sync.ds_syncid = 0;
2544 			}
2545 		} else if (dirty < ndisks) {
2546 			/*
2547 			 * Force synchronization for all dirty disks.
2548 			 * We have some non-dirty disks.
2549 			 */
2550 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2551 				if (disk->d_sync.ds_syncid != sc->sc_syncid)
2552 					continue;
2553 				if ((disk->d_flags &
2554 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2555 					continue;
2556 				}
2557 				if ((disk->d_flags &
2558 				    G_MIRROR_DISK_FLAG_DIRTY) == 0) {
2559 					continue;
2560 				}
2561 				disk->d_sync.ds_syncid = 0;
2562 			}
2563 		}
2564 
2565 		/* Reset hint. */
2566 		sc->sc_hint = NULL;
2567 		if (force) {
2568 			/* Remember to bump syncid on first write. */
2569 			sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2570 		}
2571 		state = G_MIRROR_DEVICE_STATE_RUNNING;
2572 		G_MIRROR_DEBUG(1, "Device %s state changed from %s to %s.",
2573 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state),
2574 		    g_mirror_device_state2str(state));
2575 		sc->sc_state = state;
2576 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2577 			state = g_mirror_determine_state(disk);
2578 			g_mirror_event_send(disk, state,
2579 			    G_MIRROR_EVENT_DONTWAIT);
2580 			if (state == G_MIRROR_DISK_STATE_STALE)
2581 				sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2582 		}
2583 		break;
2584 	    }
2585 	case G_MIRROR_DEVICE_STATE_RUNNING:
2586 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 0 &&
2587 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2588 			/*
2589 			 * No usable disks, so destroy the device.
2590 			 */
2591 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2592 			break;
2593 		} else if (g_mirror_ndisks(sc,
2594 		    G_MIRROR_DISK_STATE_ACTIVE) > 0 &&
2595 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2596 			/*
2597 			 * We have active disks, launch provider if it doesn't
2598 			 * exist.
2599 			 */
2600 			if (sc->sc_provider == NULL)
2601 				g_mirror_launch_provider(sc);
2602 			if (sc->sc_rootmount != NULL) {
2603 				G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p",
2604 				    __LINE__, sc->sc_rootmount);
2605 				root_mount_rel(sc->sc_rootmount);
2606 				sc->sc_rootmount = NULL;
2607 			}
2608 		}
2609 		/*
2610 		 * Genid should be bumped immediately, so do it here.
2611 		 */
2612 		if ((sc->sc_bump_id & G_MIRROR_BUMP_GENID) != 0) {
2613 			sc->sc_bump_id &= ~G_MIRROR_BUMP_GENID;
2614 			g_mirror_bump_genid(sc);
2615 		}
2616 		if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID_NOW) != 0) {
2617 			sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID_NOW;
2618 			g_mirror_bump_syncid(sc);
2619 		}
2620 		break;
2621 	default:
2622 		KASSERT(1 == 0, ("Wrong device state (%s, %s).",
2623 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state)));
2624 		break;
2625 	}
2626 }
2627 
2628 /*
2629  * Update disk state and device state if needed.
2630  */
2631 #define	DISK_STATE_CHANGED()	G_MIRROR_DEBUG(1,			\
2632 	"Disk %s state changed from %s to %s (device %s).",		\
2633 	g_mirror_get_diskname(disk),					\
2634 	g_mirror_disk_state2str(disk->d_state),				\
2635 	g_mirror_disk_state2str(state), sc->sc_name)
2636 static int
2637 g_mirror_update_disk(struct g_mirror_disk *disk, u_int state)
2638 {
2639 	struct g_mirror_softc *sc;
2640 
2641 	sc = disk->d_softc;
2642 	sx_assert(&sc->sc_lock, SX_XLOCKED);
2643 
2644 again:
2645 	G_MIRROR_DEBUG(3, "Changing disk %s state from %s to %s.",
2646 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(disk->d_state),
2647 	    g_mirror_disk_state2str(state));
2648 	switch (state) {
2649 	case G_MIRROR_DISK_STATE_NEW:
2650 		/*
2651 		 * Possible scenarios:
2652 		 * 1. New disk arrive.
2653 		 */
2654 		/* Previous state should be NONE. */
2655 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NONE,
2656 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2657 		    g_mirror_disk_state2str(disk->d_state)));
2658 		DISK_STATE_CHANGED();
2659 
2660 		disk->d_state = state;
2661 		g_topology_lock();
2662 		if (LIST_EMPTY(&sc->sc_disks))
2663 			LIST_INSERT_HEAD(&sc->sc_disks, disk, d_next);
2664 		else {
2665 			struct g_mirror_disk *dp;
2666 
2667 			LIST_FOREACH(dp, &sc->sc_disks, d_next) {
2668 				if (disk->d_priority >= dp->d_priority) {
2669 					LIST_INSERT_BEFORE(dp, disk, d_next);
2670 					dp = NULL;
2671 					break;
2672 				}
2673 				if (LIST_NEXT(dp, d_next) == NULL)
2674 					break;
2675 			}
2676 			if (dp != NULL)
2677 				LIST_INSERT_AFTER(dp, disk, d_next);
2678 		}
2679 		g_topology_unlock();
2680 		G_MIRROR_DEBUG(1, "Device %s: provider %s detected.",
2681 		    sc->sc_name, g_mirror_get_diskname(disk));
2682 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
2683 			break;
2684 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2685 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2686 		    g_mirror_device_state2str(sc->sc_state),
2687 		    g_mirror_get_diskname(disk),
2688 		    g_mirror_disk_state2str(disk->d_state)));
2689 		state = g_mirror_determine_state(disk);
2690 		if (state != G_MIRROR_DISK_STATE_NONE)
2691 			goto again;
2692 		break;
2693 	case G_MIRROR_DISK_STATE_ACTIVE:
2694 		/*
2695 		 * Possible scenarios:
2696 		 * 1. New disk does not need synchronization.
2697 		 * 2. Synchronization process finished successfully.
2698 		 */
2699 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2700 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2701 		    g_mirror_device_state2str(sc->sc_state),
2702 		    g_mirror_get_diskname(disk),
2703 		    g_mirror_disk_state2str(disk->d_state)));
2704 		/* Previous state should be NEW or SYNCHRONIZING. */
2705 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW ||
2706 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2707 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2708 		    g_mirror_disk_state2str(disk->d_state)));
2709 		DISK_STATE_CHANGED();
2710 
2711 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2712 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2713 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_FORCE_SYNC;
2714 			g_mirror_sync_stop(disk, 0);
2715 		}
2716 		disk->d_state = state;
2717 		disk->d_sync.ds_offset = 0;
2718 		disk->d_sync.ds_offset_done = 0;
2719 		g_mirror_update_idle(sc, disk);
2720 		g_mirror_update_metadata(disk);
2721 		G_MIRROR_DEBUG(1, "Device %s: provider %s activated.",
2722 		    sc->sc_name, g_mirror_get_diskname(disk));
2723 		break;
2724 	case G_MIRROR_DISK_STATE_STALE:
2725 		/*
2726 		 * Possible scenarios:
2727 		 * 1. Stale disk was connected.
2728 		 */
2729 		/* Previous state should be NEW. */
2730 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2731 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2732 		    g_mirror_disk_state2str(disk->d_state)));
2733 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2734 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2735 		    g_mirror_device_state2str(sc->sc_state),
2736 		    g_mirror_get_diskname(disk),
2737 		    g_mirror_disk_state2str(disk->d_state)));
2738 		/*
2739 		 * STALE state is only possible if device is marked
2740 		 * NOAUTOSYNC.
2741 		 */
2742 		KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) != 0,
2743 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2744 		    g_mirror_device_state2str(sc->sc_state),
2745 		    g_mirror_get_diskname(disk),
2746 		    g_mirror_disk_state2str(disk->d_state)));
2747 		DISK_STATE_CHANGED();
2748 
2749 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2750 		disk->d_state = state;
2751 		g_mirror_update_metadata(disk);
2752 		G_MIRROR_DEBUG(0, "Device %s: provider %s is stale.",
2753 		    sc->sc_name, g_mirror_get_diskname(disk));
2754 		break;
2755 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
2756 		/*
2757 		 * Possible scenarios:
2758 		 * 1. Disk which needs synchronization was connected.
2759 		 */
2760 		/* Previous state should be NEW. */
2761 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2762 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2763 		    g_mirror_disk_state2str(disk->d_state)));
2764 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2765 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2766 		    g_mirror_device_state2str(sc->sc_state),
2767 		    g_mirror_get_diskname(disk),
2768 		    g_mirror_disk_state2str(disk->d_state)));
2769 		DISK_STATE_CHANGED();
2770 
2771 		if (disk->d_state == G_MIRROR_DISK_STATE_NEW)
2772 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2773 		disk->d_state = state;
2774 		if (sc->sc_provider != NULL) {
2775 			g_mirror_sync_start(disk);
2776 			g_mirror_update_metadata(disk);
2777 		}
2778 		break;
2779 	case G_MIRROR_DISK_STATE_DISCONNECTED:
2780 		/*
2781 		 * Possible scenarios:
2782 		 * 1. Device wasn't running yet, but disk disappear.
2783 		 * 2. Disk was active and disapppear.
2784 		 * 3. Disk disappear during synchronization process.
2785 		 */
2786 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING) {
2787 			/*
2788 			 * Previous state should be ACTIVE, STALE or
2789 			 * SYNCHRONIZING.
2790 			 */
2791 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
2792 			    disk->d_state == G_MIRROR_DISK_STATE_STALE ||
2793 			    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2794 			    ("Wrong disk state (%s, %s).",
2795 			    g_mirror_get_diskname(disk),
2796 			    g_mirror_disk_state2str(disk->d_state)));
2797 		} else if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING) {
2798 			/* Previous state should be NEW. */
2799 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2800 			    ("Wrong disk state (%s, %s).",
2801 			    g_mirror_get_diskname(disk),
2802 			    g_mirror_disk_state2str(disk->d_state)));
2803 			/*
2804 			 * Reset bumping syncid if disk disappeared in STARTING
2805 			 * state.
2806 			 */
2807 			if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0)
2808 				sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
2809 #ifdef	INVARIANTS
2810 		} else {
2811 			KASSERT(1 == 0, ("Wrong device state (%s, %s, %s, %s).",
2812 			    sc->sc_name,
2813 			    g_mirror_device_state2str(sc->sc_state),
2814 			    g_mirror_get_diskname(disk),
2815 			    g_mirror_disk_state2str(disk->d_state)));
2816 #endif
2817 		}
2818 		DISK_STATE_CHANGED();
2819 		G_MIRROR_DEBUG(0, "Device %s: provider %s disconnected.",
2820 		    sc->sc_name, g_mirror_get_diskname(disk));
2821 
2822 		g_mirror_destroy_disk(disk);
2823 		break;
2824 	case G_MIRROR_DISK_STATE_DESTROY:
2825 	    {
2826 		int error;
2827 
2828 		error = g_mirror_clear_metadata(disk);
2829 		if (error != 0) {
2830 			G_MIRROR_DEBUG(0,
2831 			    "Device %s: failed to clear metadata on %s: %d.",
2832 			    sc->sc_name, g_mirror_get_diskname(disk), error);
2833 			break;
2834 		}
2835 		DISK_STATE_CHANGED();
2836 		G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.",
2837 		    sc->sc_name, g_mirror_get_diskname(disk));
2838 
2839 		g_mirror_destroy_disk(disk);
2840 		sc->sc_ndisks--;
2841 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2842 			g_mirror_update_metadata(disk);
2843 		}
2844 		break;
2845 	    }
2846 	default:
2847 		KASSERT(1 == 0, ("Unknown state (%u).", state));
2848 		break;
2849 	}
2850 	return (0);
2851 }
2852 #undef	DISK_STATE_CHANGED
2853 
2854 int
2855 g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md)
2856 {
2857 	struct g_provider *pp;
2858 	u_char *buf;
2859 	int error;
2860 
2861 	g_topology_assert();
2862 
2863 	error = g_access(cp, 1, 0, 0);
2864 	if (error != 0)
2865 		return (error);
2866 	pp = cp->provider;
2867 	g_topology_unlock();
2868 	/* Metadata are stored on last sector. */
2869 	buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
2870 	    &error);
2871 	g_topology_lock();
2872 	g_access(cp, -1, 0, 0);
2873 	if (buf == NULL) {
2874 		G_MIRROR_DEBUG(1, "Cannot read metadata from %s (error=%d).",
2875 		    cp->provider->name, error);
2876 		return (error);
2877 	}
2878 
2879 	/* Decode metadata. */
2880 	error = mirror_metadata_decode(buf, md);
2881 	g_free(buf);
2882 	if (strcmp(md->md_magic, G_MIRROR_MAGIC) != 0)
2883 		return (EINVAL);
2884 	if (md->md_version > G_MIRROR_VERSION) {
2885 		G_MIRROR_DEBUG(0,
2886 		    "Kernel module is too old to handle metadata from %s.",
2887 		    cp->provider->name);
2888 		return (EINVAL);
2889 	}
2890 	if (error != 0) {
2891 		G_MIRROR_DEBUG(1, "MD5 metadata hash mismatch for provider %s.",
2892 		    cp->provider->name);
2893 		return (error);
2894 	}
2895 
2896 	return (0);
2897 }
2898 
2899 static int
2900 g_mirror_check_metadata(struct g_mirror_softc *sc, struct g_provider *pp,
2901     struct g_mirror_metadata *md)
2902 {
2903 
2904 	G_MIRROR_DEBUG(2, "%s: md_did 0x%u disk %s device %s md_all 0x%x "
2905 	    "sc_ndisks 0x%x md_slice 0x%x sc_slice 0x%x md_balance 0x%x "
2906 	    "sc_balance 0x%x sc_mediasize 0x%jx pp_mediasize 0x%jx "
2907 	    "md_sectorsize 0x%x sc_sectorsize 0x%x md_mflags 0x%jx "
2908 	    "md_dflags 0x%jx md_syncid 0x%x md_genid 0x%x md_priority 0x%x "
2909 	    "sc_state 0x%x.",
2910 	    __func__, md->md_did, pp->name, sc->sc_name, md->md_all,
2911 	    sc->sc_ndisks, md->md_slice, sc->sc_slice, md->md_balance,
2912 	    sc->sc_balance, (uintmax_t)sc->sc_mediasize,
2913 	    (uintmax_t)pp->mediasize, md->md_sectorsize, sc->sc_sectorsize,
2914 	    (uintmax_t)md->md_mflags, (uintmax_t)md->md_dflags, md->md_syncid,
2915 	    md->md_genid, md->md_priority, sc->sc_state);
2916 
2917 	if (g_mirror_id2disk(sc, md->md_did) != NULL) {
2918 		G_MIRROR_DEBUG(1, "Disk %s (id=%u) already exists, skipping.",
2919 		    pp->name, md->md_did);
2920 		return (EEXIST);
2921 	}
2922 	if (sc->sc_mediasize > pp->mediasize) {
2923 		G_MIRROR_DEBUG(1,
2924 		    "Invalid size of disk %s (device %s), skipping.", pp->name,
2925 		    sc->sc_name);
2926 		return (EINVAL);
2927 	}
2928 	if (md->md_sectorsize != sc->sc_sectorsize) {
2929 		G_MIRROR_DEBUG(1,
2930 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2931 		    "md_sectorsize", pp->name, sc->sc_name);
2932 		return (EINVAL);
2933 	}
2934 	if ((sc->sc_sectorsize % pp->sectorsize) != 0) {
2935 		G_MIRROR_DEBUG(1,
2936 		    "Invalid sector size of disk %s (device %s), skipping.",
2937 		    pp->name, sc->sc_name);
2938 		return (EINVAL);
2939 	}
2940 	if ((md->md_mflags & ~G_MIRROR_DEVICE_FLAG_MASK) != 0) {
2941 		G_MIRROR_DEBUG(1,
2942 		    "Invalid device flags on disk %s (device %s), skipping.",
2943 		    pp->name, sc->sc_name);
2944 		return (EINVAL);
2945 	}
2946 	if ((md->md_dflags & ~G_MIRROR_DISK_FLAG_MASK) != 0) {
2947 		G_MIRROR_DEBUG(1,
2948 		    "Invalid disk flags on disk %s (device %s), skipping.",
2949 		    pp->name, sc->sc_name);
2950 		return (EINVAL);
2951 	}
2952 	return (0);
2953 }
2954 
2955 int
2956 g_mirror_add_disk(struct g_mirror_softc *sc, struct g_provider *pp,
2957     struct g_mirror_metadata *md)
2958 {
2959 	struct g_mirror_disk *disk;
2960 	int error;
2961 
2962 	g_topology_assert_not();
2963 	G_MIRROR_DEBUG(2, "Adding disk %s.", pp->name);
2964 
2965 	error = g_mirror_check_metadata(sc, pp, md);
2966 	if (error != 0)
2967 		return (error);
2968 
2969 	if (md->md_genid < sc->sc_genid) {
2970 		G_MIRROR_DEBUG(0, "Component %s (device %s) broken, skipping.",
2971 		    pp->name, sc->sc_name);
2972 		return (EINVAL);
2973 	}
2974 
2975 	/*
2976 	 * If the component disk we're tasting has newer metadata than the
2977 	 * STARTING gmirror device, refresh the device from the component.
2978 	 */
2979 	error = g_mirror_refresh_device(sc, pp, md);
2980 	if (error != 0)
2981 		return (error);
2982 
2983 	disk = g_mirror_init_disk(sc, pp, md, &error);
2984 	if (disk == NULL)
2985 		return (error);
2986 	error = g_mirror_event_send(disk, G_MIRROR_DISK_STATE_NEW,
2987 	    G_MIRROR_EVENT_WAIT);
2988 	if (error != 0)
2989 		return (error);
2990 	if (md->md_version < G_MIRROR_VERSION) {
2991 		G_MIRROR_DEBUG(0, "Upgrading metadata on %s (v%d->v%d).",
2992 		    pp->name, md->md_version, G_MIRROR_VERSION);
2993 		g_mirror_update_metadata(disk);
2994 	}
2995 	return (0);
2996 }
2997 
2998 static void
2999 g_mirror_destroy_delayed(void *arg, int flag)
3000 {
3001 	struct g_mirror_softc *sc;
3002 	int error;
3003 
3004 	if (flag == EV_CANCEL) {
3005 		G_MIRROR_DEBUG(1, "Destroying canceled.");
3006 		return;
3007 	}
3008 	sc = arg;
3009 	g_topology_unlock();
3010 	sx_xlock(&sc->sc_lock);
3011 	KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) == 0,
3012 	    ("DESTROY flag set on %s.", sc->sc_name));
3013 	KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_CLOSEWAIT) != 0,
3014 	    ("CLOSEWAIT flag not set on %s.", sc->sc_name));
3015 	G_MIRROR_DEBUG(1, "Destroying %s (delayed).", sc->sc_name);
3016 	error = g_mirror_destroy(sc, G_MIRROR_DESTROY_SOFT);
3017 	if (error != 0) {
3018 		G_MIRROR_DEBUG(0, "Cannot destroy %s (error=%d).",
3019 		    sc->sc_name, error);
3020 		sx_xunlock(&sc->sc_lock);
3021 	}
3022 	g_topology_lock();
3023 }
3024 
3025 static int
3026 g_mirror_access(struct g_provider *pp, int acr, int acw, int ace)
3027 {
3028 	struct g_mirror_softc *sc;
3029 	int error = 0;
3030 
3031 	g_topology_assert();
3032 	G_MIRROR_DEBUG(2, "Access request for %s: r%dw%de%d.", pp->name, acr,
3033 	    acw, ace);
3034 
3035 	sc = pp->private;
3036 	KASSERT(sc != NULL, ("NULL softc (provider=%s).", pp->name));
3037 
3038 	g_topology_unlock();
3039 	sx_xlock(&sc->sc_lock);
3040 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0 ||
3041 	    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_CLOSEWAIT) != 0 ||
3042 	    LIST_EMPTY(&sc->sc_disks)) {
3043 		if (acr > 0 || acw > 0 || ace > 0)
3044 			error = ENXIO;
3045 		goto end;
3046 	}
3047 	sc->sc_provider_open += acr + acw + ace;
3048 	if (pp->acw + acw == 0)
3049 		g_mirror_idle(sc, 0);
3050 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_CLOSEWAIT) != 0 &&
3051 	    sc->sc_provider_open == 0)
3052 		g_post_event(g_mirror_destroy_delayed, sc, M_WAITOK, sc, NULL);
3053 end:
3054 	sx_xunlock(&sc->sc_lock);
3055 	g_topology_lock();
3056 	return (error);
3057 }
3058 
3059 static void
3060 g_mirror_reinit_from_metadata(struct g_mirror_softc *sc,
3061     const struct g_mirror_metadata *md)
3062 {
3063 
3064 	sc->sc_genid = md->md_genid;
3065 	sc->sc_syncid = md->md_syncid;
3066 
3067 	sc->sc_slice = md->md_slice;
3068 	sc->sc_balance = md->md_balance;
3069 	sc->sc_mediasize = md->md_mediasize;
3070 	sc->sc_ndisks = md->md_all;
3071 	sc->sc_flags &= ~G_MIRROR_DEVICE_FLAG_MASK;
3072 	sc->sc_flags |= (md->md_mflags & G_MIRROR_DEVICE_FLAG_MASK);
3073 }
3074 
3075 struct g_geom *
3076 g_mirror_create(struct g_class *mp, const struct g_mirror_metadata *md,
3077     u_int type)
3078 {
3079 	struct g_mirror_softc *sc;
3080 	struct g_geom *gp;
3081 	int error, timeout;
3082 
3083 	g_topology_assert();
3084 	G_MIRROR_DEBUG(1, "Creating device %s (id=%u).", md->md_name,
3085 	    md->md_mid);
3086 
3087 	/* One disk is minimum. */
3088 	if (md->md_all < 1)
3089 		return (NULL);
3090 	/*
3091 	 * Action geom.
3092 	 */
3093 	gp = g_new_geomf(mp, "%s", md->md_name);
3094 	sc = malloc(sizeof(*sc), M_MIRROR, M_WAITOK | M_ZERO);
3095 	gp->start = g_mirror_start;
3096 	gp->orphan = g_mirror_orphan;
3097 	gp->access = g_mirror_access;
3098 	gp->dumpconf = g_mirror_dumpconf;
3099 
3100 	sc->sc_type = type;
3101 	sc->sc_id = md->md_mid;
3102 	g_mirror_reinit_from_metadata(sc, md);
3103 	sc->sc_sectorsize = md->md_sectorsize;
3104 	sc->sc_bump_id = 0;
3105 	sc->sc_idle = 1;
3106 	sc->sc_last_write = time_uptime;
3107 	sc->sc_writes = 0;
3108 	sc->sc_refcnt = 1;
3109 	sx_init(&sc->sc_lock, "gmirror:lock");
3110 	TAILQ_INIT(&sc->sc_queue);
3111 	mtx_init(&sc->sc_queue_mtx, "gmirror:queue", NULL, MTX_DEF);
3112 	TAILQ_INIT(&sc->sc_regular_delayed);
3113 	TAILQ_INIT(&sc->sc_inflight);
3114 	TAILQ_INIT(&sc->sc_sync_delayed);
3115 	LIST_INIT(&sc->sc_disks);
3116 	TAILQ_INIT(&sc->sc_events);
3117 	mtx_init(&sc->sc_events_mtx, "gmirror:events", NULL, MTX_DEF);
3118 	callout_init(&sc->sc_callout, 1);
3119 	mtx_init(&sc->sc_done_mtx, "gmirror:done", NULL, MTX_DEF);
3120 	sc->sc_state = G_MIRROR_DEVICE_STATE_STARTING;
3121 	gp->softc = sc;
3122 	sc->sc_geom = gp;
3123 	sc->sc_provider = NULL;
3124 	sc->sc_provider_open = 0;
3125 	/*
3126 	 * Synchronization geom.
3127 	 */
3128 	gp = g_new_geomf(mp, "%s.sync", md->md_name);
3129 	gp->softc = sc;
3130 	gp->orphan = g_mirror_orphan;
3131 	sc->sc_sync.ds_geom = gp;
3132 	sc->sc_sync.ds_ndisks = 0;
3133 	error = kproc_create(g_mirror_worker, sc, &sc->sc_worker, 0, 0,
3134 	    "g_mirror %s", md->md_name);
3135 	if (error != 0) {
3136 		G_MIRROR_DEBUG(1, "Cannot create kernel thread for %s.",
3137 		    sc->sc_name);
3138 		g_destroy_geom(sc->sc_sync.ds_geom);
3139 		g_destroy_geom(sc->sc_geom);
3140 		g_mirror_free_device(sc);
3141 		return (NULL);
3142 	}
3143 
3144 	G_MIRROR_DEBUG(1, "Device %s created (%u components, id=%u).",
3145 	    sc->sc_name, sc->sc_ndisks, sc->sc_id);
3146 
3147 	sc->sc_rootmount = root_mount_hold("GMIRROR");
3148 	G_MIRROR_DEBUG(1, "root_mount_hold %p", sc->sc_rootmount);
3149 	/*
3150 	 * Run timeout.
3151 	 */
3152 	timeout = g_mirror_timeout * hz;
3153 	callout_reset(&sc->sc_callout, timeout, g_mirror_go, sc);
3154 	return (sc->sc_geom);
3155 }
3156 
3157 int
3158 g_mirror_destroy(struct g_mirror_softc *sc, int how)
3159 {
3160 	struct g_mirror_disk *disk;
3161 
3162 	g_topology_assert_not();
3163 	sx_assert(&sc->sc_lock, SX_XLOCKED);
3164 
3165 	if (sc->sc_provider_open != 0) {
3166 		switch (how) {
3167 		case G_MIRROR_DESTROY_SOFT:
3168 			G_MIRROR_DEBUG(1,
3169 			    "Device %s is still open (%d).", sc->sc_name,
3170 			    sc->sc_provider_open);
3171 			return (EBUSY);
3172 		case G_MIRROR_DESTROY_DELAYED:
3173 			G_MIRROR_DEBUG(1,
3174 			    "Device %s will be destroyed on last close.",
3175 			    sc->sc_name);
3176 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
3177 				if (disk->d_state ==
3178 				    G_MIRROR_DISK_STATE_SYNCHRONIZING) {
3179 					g_mirror_sync_stop(disk, 1);
3180 				}
3181 			}
3182 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_CLOSEWAIT;
3183 			return (EBUSY);
3184 		case G_MIRROR_DESTROY_HARD:
3185 			G_MIRROR_DEBUG(1, "Device %s is still open, so it "
3186 			    "can't be definitely removed.", sc->sc_name);
3187 		}
3188 	}
3189 
3190 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
3191 		sx_xunlock(&sc->sc_lock);
3192 		return (0);
3193 	}
3194 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
3195 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DRAIN;
3196 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
3197 	sx_xunlock(&sc->sc_lock);
3198 	mtx_lock(&sc->sc_queue_mtx);
3199 	wakeup(sc);
3200 	mtx_unlock(&sc->sc_queue_mtx);
3201 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, &sc->sc_worker);
3202 	while (sc->sc_worker != NULL)
3203 		tsleep(&sc->sc_worker, PRIBIO, "m:destroy", hz / 5);
3204 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, &sc->sc_worker);
3205 	sx_xlock(&sc->sc_lock);
3206 	g_mirror_destroy_device(sc);
3207 	return (0);
3208 }
3209 
3210 static void
3211 g_mirror_taste_orphan(struct g_consumer *cp)
3212 {
3213 
3214 	KASSERT(1 == 0, ("%s called while tasting %s.", __func__,
3215 	    cp->provider->name));
3216 }
3217 
3218 static struct g_geom *
3219 g_mirror_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
3220 {
3221 	struct g_mirror_metadata md;
3222 	struct g_mirror_softc *sc;
3223 	struct g_consumer *cp;
3224 	struct g_geom *gp;
3225 	int error;
3226 
3227 	g_topology_assert();
3228 	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
3229 	G_MIRROR_DEBUG(2, "Tasting %s.", pp->name);
3230 
3231 	gp = g_new_geomf(mp, "mirror:taste");
3232 	/*
3233 	 * This orphan function should be never called.
3234 	 */
3235 	gp->orphan = g_mirror_taste_orphan;
3236 	cp = g_new_consumer(gp);
3237 	g_attach(cp, pp);
3238 	error = g_mirror_read_metadata(cp, &md);
3239 	g_detach(cp);
3240 	g_destroy_consumer(cp);
3241 	g_destroy_geom(gp);
3242 	if (error != 0)
3243 		return (NULL);
3244 	gp = NULL;
3245 
3246 	if (md.md_provider[0] != '\0' &&
3247 	    !g_compare_names(md.md_provider, pp->name))
3248 		return (NULL);
3249 	if (md.md_provsize != 0 && md.md_provsize != pp->mediasize)
3250 		return (NULL);
3251 	if ((md.md_dflags & G_MIRROR_DISK_FLAG_INACTIVE) != 0) {
3252 		G_MIRROR_DEBUG(0,
3253 		    "Device %s: provider %s marked as inactive, skipping.",
3254 		    md.md_name, pp->name);
3255 		return (NULL);
3256 	}
3257 	if (g_mirror_debug >= 2)
3258 		mirror_metadata_dump(&md);
3259 
3260 	/*
3261 	 * Let's check if device already exists.
3262 	 */
3263 	sc = NULL;
3264 	LIST_FOREACH(gp, &mp->geom, geom) {
3265 		sc = gp->softc;
3266 		if (sc == NULL)
3267 			continue;
3268 		if (sc->sc_type != G_MIRROR_TYPE_AUTOMATIC)
3269 			continue;
3270 		if (sc->sc_sync.ds_geom == gp)
3271 			continue;
3272 		if (strcmp(md.md_name, sc->sc_name) != 0)
3273 			continue;
3274 		if (md.md_mid != sc->sc_id) {
3275 			G_MIRROR_DEBUG(0, "Device %s already configured.",
3276 			    sc->sc_name);
3277 			return (NULL);
3278 		}
3279 		break;
3280 	}
3281 	if (gp == NULL) {
3282 		gp = g_mirror_create(mp, &md, G_MIRROR_TYPE_AUTOMATIC);
3283 		if (gp == NULL) {
3284 			G_MIRROR_DEBUG(0, "Cannot create device %s.",
3285 			    md.md_name);
3286 			return (NULL);
3287 		}
3288 		sc = gp->softc;
3289 	}
3290 	G_MIRROR_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
3291 	g_topology_unlock();
3292 	sx_xlock(&sc->sc_lock);
3293 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_TASTING;
3294 	error = g_mirror_add_disk(sc, pp, &md);
3295 	sc->sc_flags &= ~G_MIRROR_DEVICE_FLAG_TASTING;
3296 	if (error != 0) {
3297 		G_MIRROR_DEBUG(0, "Cannot add disk %s to %s (error=%d).",
3298 		    pp->name, gp->name, error);
3299 		if (LIST_EMPTY(&sc->sc_disks)) {
3300 			g_cancel_event(sc);
3301 			g_mirror_destroy(sc, G_MIRROR_DESTROY_HARD);
3302 			g_topology_lock();
3303 			return (NULL);
3304 		}
3305 		gp = NULL;
3306 	}
3307 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
3308 		g_mirror_destroy(sc, G_MIRROR_DESTROY_HARD);
3309 		g_topology_lock();
3310 		return (NULL);
3311 	}
3312 	sx_xunlock(&sc->sc_lock);
3313 	g_topology_lock();
3314 	return (gp);
3315 }
3316 
3317 static void
3318 g_mirror_resize(struct g_consumer *cp)
3319 {
3320 	struct g_mirror_disk *disk;
3321 
3322 	g_topology_assert();
3323 	g_trace(G_T_TOPOLOGY, "%s(%s)", __func__, cp->provider->name);
3324 
3325 	disk = cp->private;
3326 	if (disk == NULL)
3327 		return;
3328 	g_topology_unlock();
3329 	g_mirror_update_metadata(disk);
3330 	g_topology_lock();
3331 }
3332 
3333 static int
3334 g_mirror_destroy_geom(struct gctl_req *req __unused,
3335     struct g_class *mp __unused, struct g_geom *gp)
3336 {
3337 	struct g_mirror_softc *sc;
3338 	int error;
3339 
3340 	g_topology_unlock();
3341 	sc = gp->softc;
3342 	sx_xlock(&sc->sc_lock);
3343 	g_cancel_event(sc);
3344 	error = g_mirror_destroy(gp->softc, G_MIRROR_DESTROY_SOFT);
3345 	if (error != 0)
3346 		sx_xunlock(&sc->sc_lock);
3347 	g_topology_lock();
3348 	return (error);
3349 }
3350 
3351 static void
3352 g_mirror_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
3353     struct g_consumer *cp, struct g_provider *pp)
3354 {
3355 	struct g_mirror_softc *sc;
3356 
3357 	g_topology_assert();
3358 
3359 	sc = gp->softc;
3360 	if (sc == NULL)
3361 		return;
3362 	/* Skip synchronization geom. */
3363 	if (gp == sc->sc_sync.ds_geom)
3364 		return;
3365 	if (pp != NULL) {
3366 		/* Nothing here. */
3367 	} else if (cp != NULL) {
3368 		struct g_mirror_disk *disk;
3369 
3370 		disk = cp->private;
3371 		if (disk == NULL)
3372 			return;
3373 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)disk->d_id);
3374 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
3375 			sbuf_printf(sb, "%s<Synchronized>", indent);
3376 			if (disk->d_sync.ds_offset == 0)
3377 				sbuf_cat(sb, "0%");
3378 			else
3379 				sbuf_printf(sb, "%u%%",
3380 				    (u_int)((disk->d_sync.ds_offset * 100) /
3381 				    sc->sc_mediasize));
3382 			sbuf_cat(sb, "</Synchronized>\n");
3383 			if (disk->d_sync.ds_offset > 0)
3384 				sbuf_printf(sb, "%s<BytesSynced>%jd"
3385 				    "</BytesSynced>\n", indent,
3386 				    (intmax_t)disk->d_sync.ds_offset);
3387 		}
3388 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent,
3389 		    disk->d_sync.ds_syncid);
3390 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent,
3391 		    disk->d_genid);
3392 		sbuf_printf(sb, "%s<Flags>", indent);
3393 		if (disk->d_flags == 0)
3394 			sbuf_cat(sb, "NONE");
3395 		else {
3396 			int first = 1;
3397 
3398 #define	ADD_FLAG(flag, name)	do {					\
3399 	if ((disk->d_flags & (flag)) != 0) {				\
3400 		if (!first)						\
3401 			sbuf_cat(sb, ", ");				\
3402 		else							\
3403 			first = 0;					\
3404 		sbuf_cat(sb, name);					\
3405 	}								\
3406 } while (0)
3407 			ADD_FLAG(G_MIRROR_DISK_FLAG_DIRTY, "DIRTY");
3408 			ADD_FLAG(G_MIRROR_DISK_FLAG_HARDCODED, "HARDCODED");
3409 			ADD_FLAG(G_MIRROR_DISK_FLAG_INACTIVE, "INACTIVE");
3410 			ADD_FLAG(G_MIRROR_DISK_FLAG_SYNCHRONIZING,
3411 			    "SYNCHRONIZING");
3412 			ADD_FLAG(G_MIRROR_DISK_FLAG_FORCE_SYNC, "FORCE_SYNC");
3413 			ADD_FLAG(G_MIRROR_DISK_FLAG_BROKEN, "BROKEN");
3414 #undef	ADD_FLAG
3415 		}
3416 		sbuf_cat(sb, "</Flags>\n");
3417 		sbuf_printf(sb, "%s<Priority>%u</Priority>\n", indent,
3418 		    disk->d_priority);
3419 		sbuf_printf(sb, "%s<State>%s</State>\n", indent,
3420 		    g_mirror_disk_state2str(disk->d_state));
3421 	} else {
3422 		sbuf_printf(sb, "%s<Type>", indent);
3423 		switch (sc->sc_type) {
3424 		case G_MIRROR_TYPE_AUTOMATIC:
3425 			sbuf_cat(sb, "AUTOMATIC");
3426 			break;
3427 		case G_MIRROR_TYPE_MANUAL:
3428 			sbuf_cat(sb, "MANUAL");
3429 			break;
3430 		default:
3431 			sbuf_cat(sb, "UNKNOWN");
3432 			break;
3433 		}
3434 		sbuf_cat(sb, "</Type>\n");
3435 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)sc->sc_id);
3436 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent, sc->sc_syncid);
3437 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent, sc->sc_genid);
3438 		sbuf_printf(sb, "%s<Flags>", indent);
3439 		if (sc->sc_flags == 0)
3440 			sbuf_cat(sb, "NONE");
3441 		else {
3442 			int first = 1;
3443 
3444 #define	ADD_FLAG(flag, name)	do {					\
3445 	if ((sc->sc_flags & (flag)) != 0) {				\
3446 		if (!first)						\
3447 			sbuf_cat(sb, ", ");				\
3448 		else							\
3449 			first = 0;					\
3450 		sbuf_cat(sb, name);					\
3451 	}								\
3452 } while (0)
3453 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOFAILSYNC, "NOFAILSYNC");
3454 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOAUTOSYNC, "NOAUTOSYNC");
3455 #undef	ADD_FLAG
3456 		}
3457 		sbuf_cat(sb, "</Flags>\n");
3458 		sbuf_printf(sb, "%s<Slice>%u</Slice>\n", indent,
3459 		    (u_int)sc->sc_slice);
3460 		sbuf_printf(sb, "%s<Balance>%s</Balance>\n", indent,
3461 		    balance_name(sc->sc_balance));
3462 		sbuf_printf(sb, "%s<Components>%u</Components>\n", indent,
3463 		    sc->sc_ndisks);
3464 		sbuf_printf(sb, "%s<State>", indent);
3465 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
3466 			sbuf_printf(sb, "%s", "STARTING");
3467 		else if (sc->sc_ndisks ==
3468 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE))
3469 			sbuf_printf(sb, "%s", "COMPLETE");
3470 		else
3471 			sbuf_printf(sb, "%s", "DEGRADED");
3472 		sbuf_cat(sb, "</State>\n");
3473 	}
3474 }
3475 
3476 static void
3477 g_mirror_shutdown_post_sync(void *arg, int howto)
3478 {
3479 	struct g_class *mp;
3480 	struct g_geom *gp, *gp2;
3481 	struct g_mirror_softc *sc;
3482 	int error;
3483 
3484 	if (panicstr != NULL)
3485 		return;
3486 
3487 	mp = arg;
3488 	g_topology_lock();
3489 	g_mirror_shutdown = 1;
3490 	LIST_FOREACH_SAFE(gp, &mp->geom, geom, gp2) {
3491 		if ((sc = gp->softc) == NULL)
3492 			continue;
3493 		/* Skip synchronization geom. */
3494 		if (gp == sc->sc_sync.ds_geom)
3495 			continue;
3496 		g_topology_unlock();
3497 		sx_xlock(&sc->sc_lock);
3498 		g_mirror_idle(sc, -1);
3499 		g_cancel_event(sc);
3500 		error = g_mirror_destroy(sc, G_MIRROR_DESTROY_DELAYED);
3501 		if (error != 0)
3502 			sx_xunlock(&sc->sc_lock);
3503 		g_topology_lock();
3504 	}
3505 	g_topology_unlock();
3506 }
3507 
3508 static void
3509 g_mirror_init(struct g_class *mp)
3510 {
3511 
3512 	g_mirror_post_sync = EVENTHANDLER_REGISTER(shutdown_post_sync,
3513 	    g_mirror_shutdown_post_sync, mp, SHUTDOWN_PRI_FIRST);
3514 	if (g_mirror_post_sync == NULL)
3515 		G_MIRROR_DEBUG(0, "Warning! Cannot register shutdown event.");
3516 }
3517 
3518 static void
3519 g_mirror_fini(struct g_class *mp)
3520 {
3521 
3522 	if (g_mirror_post_sync != NULL)
3523 		EVENTHANDLER_DEREGISTER(shutdown_post_sync, g_mirror_post_sync);
3524 }
3525 
3526 /*
3527  * Refresh the mirror device's metadata when gmirror encounters a newer
3528  * generation as the individual components are being added to the mirror set.
3529  */
3530 static int
3531 g_mirror_refresh_device(struct g_mirror_softc *sc, const struct g_provider *pp,
3532     const struct g_mirror_metadata *md)
3533 {
3534 
3535 	g_topology_assert_not();
3536 	sx_assert(&sc->sc_lock, SX_XLOCKED);
3537 
3538 	KASSERT(sc->sc_genid <= md->md_genid,
3539 	    ("%s: attempted to refresh from stale component %s (device %s) "
3540 	    "(%u < %u).", __func__, pp->name, sc->sc_name, md->md_genid,
3541 	    sc->sc_genid));
3542 
3543 	if (sc->sc_genid > md->md_genid || (sc->sc_genid == md->md_genid &&
3544 	    sc->sc_syncid >= md->md_syncid))
3545 		return (0);
3546 
3547 	G_MIRROR_DEBUG(0, "Found newer version for device %s (genid: curr=%u "
3548 	    "new=%u; syncid: curr=%u new=%u; ndisks: curr=%u new=%u; "
3549 	    "provider=%s).", sc->sc_name, sc->sc_genid, md->md_genid,
3550 	    sc->sc_syncid, md->md_syncid, sc->sc_ndisks, md->md_all, pp->name);
3551 
3552 	if (sc->sc_state != G_MIRROR_DEVICE_STATE_STARTING) {
3553 		/* Probable data corruption detected */
3554 		G_MIRROR_DEBUG(0, "Cannot refresh metadata in %s state "
3555 		    "(device=%s genid=%u). A stale mirror device was launched.",
3556 		    g_mirror_device_state2str(sc->sc_state), sc->sc_name,
3557 		    sc->sc_genid);
3558 		return (EINVAL);
3559 	}
3560 
3561 	/* Update softc */
3562 	g_mirror_reinit_from_metadata(sc, md);
3563 
3564 	G_MIRROR_DEBUG(1, "Refresh device %s (id=%u, state=%s) from disk %s "
3565 	    "(genid=%u syncid=%u md_all=%u).", sc->sc_name, md->md_mid,
3566 	    g_mirror_device_state2str(sc->sc_state), pp->name, md->md_genid,
3567 	    md->md_syncid, (unsigned)md->md_all);
3568 
3569 	return (0);
3570 }
3571 
3572 DECLARE_GEOM_CLASS(g_mirror_class, g_mirror);
3573 MODULE_VERSION(geom_mirror, 0);
3574