xref: /freebsd/sys/geom/mirror/g_mirror.c (revision 09a53ad8f1318c5daae6cfb19d97f4f6459f0013)
1 /*-
2  * Copyright (c) 2004-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/fail.h>
33 #include <sys/kernel.h>
34 #include <sys/module.h>
35 #include <sys/limits.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/bio.h>
39 #include <sys/sbuf.h>
40 #include <sys/sysctl.h>
41 #include <sys/malloc.h>
42 #include <sys/eventhandler.h>
43 #include <vm/uma.h>
44 #include <geom/geom.h>
45 #include <sys/proc.h>
46 #include <sys/kthread.h>
47 #include <sys/sched.h>
48 #include <geom/mirror/g_mirror.h>
49 
50 FEATURE(geom_mirror, "GEOM mirroring support");
51 
52 static MALLOC_DEFINE(M_MIRROR, "mirror_data", "GEOM_MIRROR Data");
53 
54 SYSCTL_DECL(_kern_geom);
55 static SYSCTL_NODE(_kern_geom, OID_AUTO, mirror, CTLFLAG_RW, 0,
56     "GEOM_MIRROR stuff");
57 u_int g_mirror_debug = 0;
58 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, debug, CTLFLAG_RWTUN, &g_mirror_debug, 0,
59     "Debug level");
60 static u_int g_mirror_timeout = 4;
61 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, timeout, CTLFLAG_RWTUN, &g_mirror_timeout,
62     0, "Time to wait on all mirror components");
63 static u_int g_mirror_idletime = 5;
64 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, idletime, CTLFLAG_RWTUN,
65     &g_mirror_idletime, 0, "Mark components as clean when idling");
66 static u_int g_mirror_disconnect_on_failure = 1;
67 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, disconnect_on_failure, CTLFLAG_RWTUN,
68     &g_mirror_disconnect_on_failure, 0, "Disconnect component on I/O failure.");
69 static u_int g_mirror_syncreqs = 2;
70 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, sync_requests, CTLFLAG_RDTUN,
71     &g_mirror_syncreqs, 0, "Parallel synchronization I/O requests.");
72 
73 #define	MSLEEP(ident, mtx, priority, wmesg, timeout)	do {		\
74 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, (ident));	\
75 	msleep((ident), (mtx), (priority), (wmesg), (timeout));		\
76 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, (ident));	\
77 } while (0)
78 
79 static eventhandler_tag g_mirror_post_sync = NULL;
80 static int g_mirror_shutdown = 0;
81 
82 static int g_mirror_destroy_geom(struct gctl_req *req, struct g_class *mp,
83     struct g_geom *gp);
84 static g_taste_t g_mirror_taste;
85 static g_resize_t g_mirror_resize;
86 static void g_mirror_init(struct g_class *mp);
87 static void g_mirror_fini(struct g_class *mp);
88 
89 struct g_class g_mirror_class = {
90 	.name = G_MIRROR_CLASS_NAME,
91 	.version = G_VERSION,
92 	.ctlreq = g_mirror_config,
93 	.taste = g_mirror_taste,
94 	.destroy_geom = g_mirror_destroy_geom,
95 	.init = g_mirror_init,
96 	.fini = g_mirror_fini,
97 	.resize = g_mirror_resize
98 };
99 
100 
101 static void g_mirror_destroy_provider(struct g_mirror_softc *sc);
102 static int g_mirror_update_disk(struct g_mirror_disk *disk, u_int state);
103 static void g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force);
104 static void g_mirror_dumpconf(struct sbuf *sb, const char *indent,
105     struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp);
106 static void g_mirror_sync_stop(struct g_mirror_disk *disk, int type);
107 static void g_mirror_register_request(struct bio *bp);
108 static void g_mirror_sync_release(struct g_mirror_softc *sc);
109 
110 
111 static const char *
112 g_mirror_disk_state2str(int state)
113 {
114 
115 	switch (state) {
116 	case G_MIRROR_DISK_STATE_NONE:
117 		return ("NONE");
118 	case G_MIRROR_DISK_STATE_NEW:
119 		return ("NEW");
120 	case G_MIRROR_DISK_STATE_ACTIVE:
121 		return ("ACTIVE");
122 	case G_MIRROR_DISK_STATE_STALE:
123 		return ("STALE");
124 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
125 		return ("SYNCHRONIZING");
126 	case G_MIRROR_DISK_STATE_DISCONNECTED:
127 		return ("DISCONNECTED");
128 	case G_MIRROR_DISK_STATE_DESTROY:
129 		return ("DESTROY");
130 	default:
131 		return ("INVALID");
132 	}
133 }
134 
135 static const char *
136 g_mirror_device_state2str(int state)
137 {
138 
139 	switch (state) {
140 	case G_MIRROR_DEVICE_STATE_STARTING:
141 		return ("STARTING");
142 	case G_MIRROR_DEVICE_STATE_RUNNING:
143 		return ("RUNNING");
144 	default:
145 		return ("INVALID");
146 	}
147 }
148 
149 static const char *
150 g_mirror_get_diskname(struct g_mirror_disk *disk)
151 {
152 
153 	if (disk->d_consumer == NULL || disk->d_consumer->provider == NULL)
154 		return ("[unknown]");
155 	return (disk->d_name);
156 }
157 
158 /*
159  * --- Events handling functions ---
160  * Events in geom_mirror are used to maintain disks and device status
161  * from one thread to simplify locking.
162  */
163 static void
164 g_mirror_event_free(struct g_mirror_event *ep)
165 {
166 
167 	free(ep, M_MIRROR);
168 }
169 
170 int
171 g_mirror_event_send(void *arg, int state, int flags)
172 {
173 	struct g_mirror_softc *sc;
174 	struct g_mirror_disk *disk;
175 	struct g_mirror_event *ep;
176 	int error;
177 
178 	ep = malloc(sizeof(*ep), M_MIRROR, M_WAITOK);
179 	G_MIRROR_DEBUG(4, "%s: Sending event %p.", __func__, ep);
180 	if ((flags & G_MIRROR_EVENT_DEVICE) != 0) {
181 		disk = NULL;
182 		sc = arg;
183 	} else {
184 		disk = arg;
185 		sc = disk->d_softc;
186 	}
187 	ep->e_disk = disk;
188 	ep->e_state = state;
189 	ep->e_flags = flags;
190 	ep->e_error = 0;
191 	mtx_lock(&sc->sc_events_mtx);
192 	TAILQ_INSERT_TAIL(&sc->sc_events, ep, e_next);
193 	mtx_unlock(&sc->sc_events_mtx);
194 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
195 	mtx_lock(&sc->sc_queue_mtx);
196 	wakeup(sc);
197 	mtx_unlock(&sc->sc_queue_mtx);
198 	if ((flags & G_MIRROR_EVENT_DONTWAIT) != 0)
199 		return (0);
200 	sx_assert(&sc->sc_lock, SX_XLOCKED);
201 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, ep);
202 	sx_xunlock(&sc->sc_lock);
203 	while ((ep->e_flags & G_MIRROR_EVENT_DONE) == 0) {
204 		mtx_lock(&sc->sc_events_mtx);
205 		MSLEEP(ep, &sc->sc_events_mtx, PRIBIO | PDROP, "m:event",
206 		    hz * 5);
207 	}
208 	error = ep->e_error;
209 	g_mirror_event_free(ep);
210 	sx_xlock(&sc->sc_lock);
211 	return (error);
212 }
213 
214 static struct g_mirror_event *
215 g_mirror_event_get(struct g_mirror_softc *sc)
216 {
217 	struct g_mirror_event *ep;
218 
219 	mtx_lock(&sc->sc_events_mtx);
220 	ep = TAILQ_FIRST(&sc->sc_events);
221 	mtx_unlock(&sc->sc_events_mtx);
222 	return (ep);
223 }
224 
225 static void
226 g_mirror_event_remove(struct g_mirror_softc *sc, struct g_mirror_event *ep)
227 {
228 
229 	mtx_lock(&sc->sc_events_mtx);
230 	TAILQ_REMOVE(&sc->sc_events, ep, e_next);
231 	mtx_unlock(&sc->sc_events_mtx);
232 }
233 
234 static void
235 g_mirror_event_cancel(struct g_mirror_disk *disk)
236 {
237 	struct g_mirror_softc *sc;
238 	struct g_mirror_event *ep, *tmpep;
239 
240 	sc = disk->d_softc;
241 	sx_assert(&sc->sc_lock, SX_XLOCKED);
242 
243 	mtx_lock(&sc->sc_events_mtx);
244 	TAILQ_FOREACH_SAFE(ep, &sc->sc_events, e_next, tmpep) {
245 		if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0)
246 			continue;
247 		if (ep->e_disk != disk)
248 			continue;
249 		TAILQ_REMOVE(&sc->sc_events, ep, e_next);
250 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
251 			g_mirror_event_free(ep);
252 		else {
253 			ep->e_error = ECANCELED;
254 			wakeup(ep);
255 		}
256 	}
257 	mtx_unlock(&sc->sc_events_mtx);
258 }
259 
260 /*
261  * Return the number of disks in given state.
262  * If state is equal to -1, count all connected disks.
263  */
264 u_int
265 g_mirror_ndisks(struct g_mirror_softc *sc, int state)
266 {
267 	struct g_mirror_disk *disk;
268 	u_int n = 0;
269 
270 	sx_assert(&sc->sc_lock, SX_LOCKED);
271 
272 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
273 		if (state == -1 || disk->d_state == state)
274 			n++;
275 	}
276 	return (n);
277 }
278 
279 /*
280  * Find a disk in mirror by its disk ID.
281  */
282 static struct g_mirror_disk *
283 g_mirror_id2disk(struct g_mirror_softc *sc, uint32_t id)
284 {
285 	struct g_mirror_disk *disk;
286 
287 	sx_assert(&sc->sc_lock, SX_XLOCKED);
288 
289 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
290 		if (disk->d_id == id)
291 			return (disk);
292 	}
293 	return (NULL);
294 }
295 
296 static u_int
297 g_mirror_nrequests(struct g_mirror_softc *sc, struct g_consumer *cp)
298 {
299 	struct bio *bp;
300 	u_int nreqs = 0;
301 
302 	mtx_lock(&sc->sc_queue_mtx);
303 	TAILQ_FOREACH(bp, &sc->sc_queue.queue, bio_queue) {
304 		if (bp->bio_from == cp)
305 			nreqs++;
306 	}
307 	mtx_unlock(&sc->sc_queue_mtx);
308 	return (nreqs);
309 }
310 
311 static int
312 g_mirror_is_busy(struct g_mirror_softc *sc, struct g_consumer *cp)
313 {
314 
315 	if (cp->index > 0) {
316 		G_MIRROR_DEBUG(2,
317 		    "I/O requests for %s exist, can't destroy it now.",
318 		    cp->provider->name);
319 		return (1);
320 	}
321 	if (g_mirror_nrequests(sc, cp) > 0) {
322 		G_MIRROR_DEBUG(2,
323 		    "I/O requests for %s in queue, can't destroy it now.",
324 		    cp->provider->name);
325 		return (1);
326 	}
327 	return (0);
328 }
329 
330 static void
331 g_mirror_destroy_consumer(void *arg, int flags __unused)
332 {
333 	struct g_consumer *cp;
334 
335 	g_topology_assert();
336 
337 	cp = arg;
338 	G_MIRROR_DEBUG(1, "Consumer %s destroyed.", cp->provider->name);
339 	g_detach(cp);
340 	g_destroy_consumer(cp);
341 }
342 
343 static void
344 g_mirror_kill_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
345 {
346 	struct g_provider *pp;
347 	int retaste_wait;
348 
349 	g_topology_assert();
350 
351 	cp->private = NULL;
352 	if (g_mirror_is_busy(sc, cp))
353 		return;
354 	pp = cp->provider;
355 	retaste_wait = 0;
356 	if (cp->acw == 1) {
357 		if ((pp->geom->flags & G_GEOM_WITHER) == 0)
358 			retaste_wait = 1;
359 	}
360 	G_MIRROR_DEBUG(2, "Access %s r%dw%de%d = %d", pp->name, -cp->acr,
361 	    -cp->acw, -cp->ace, 0);
362 	if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
363 		g_access(cp, -cp->acr, -cp->acw, -cp->ace);
364 	if (retaste_wait) {
365 		/*
366 		 * After retaste event was send (inside g_access()), we can send
367 		 * event to detach and destroy consumer.
368 		 * A class, which has consumer to the given provider connected
369 		 * will not receive retaste event for the provider.
370 		 * This is the way how I ignore retaste events when I close
371 		 * consumers opened for write: I detach and destroy consumer
372 		 * after retaste event is sent.
373 		 */
374 		g_post_event(g_mirror_destroy_consumer, cp, M_WAITOK, NULL);
375 		return;
376 	}
377 	G_MIRROR_DEBUG(1, "Consumer %s destroyed.", pp->name);
378 	g_detach(cp);
379 	g_destroy_consumer(cp);
380 }
381 
382 static int
383 g_mirror_connect_disk(struct g_mirror_disk *disk, struct g_provider *pp)
384 {
385 	struct g_consumer *cp;
386 	int error;
387 
388 	g_topology_assert_not();
389 	KASSERT(disk->d_consumer == NULL,
390 	    ("Disk already connected (device %s).", disk->d_softc->sc_name));
391 
392 	g_topology_lock();
393 	cp = g_new_consumer(disk->d_softc->sc_geom);
394 	cp->flags |= G_CF_DIRECT_RECEIVE;
395 	error = g_attach(cp, pp);
396 	if (error != 0) {
397 		g_destroy_consumer(cp);
398 		g_topology_unlock();
399 		return (error);
400 	}
401 	error = g_access(cp, 1, 1, 1);
402 	if (error != 0) {
403 		g_detach(cp);
404 		g_destroy_consumer(cp);
405 		g_topology_unlock();
406 		G_MIRROR_DEBUG(0, "Cannot open consumer %s (error=%d).",
407 		    pp->name, error);
408 		return (error);
409 	}
410 	g_topology_unlock();
411 	disk->d_consumer = cp;
412 	disk->d_consumer->private = disk;
413 	disk->d_consumer->index = 0;
414 
415 	G_MIRROR_DEBUG(2, "Disk %s connected.", g_mirror_get_diskname(disk));
416 	return (0);
417 }
418 
419 static void
420 g_mirror_disconnect_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
421 {
422 
423 	g_topology_assert();
424 
425 	if (cp == NULL)
426 		return;
427 	if (cp->provider != NULL)
428 		g_mirror_kill_consumer(sc, cp);
429 	else
430 		g_destroy_consumer(cp);
431 }
432 
433 /*
434  * Initialize disk. This means allocate memory, create consumer, attach it
435  * to the provider and open access (r1w1e1) to it.
436  */
437 static struct g_mirror_disk *
438 g_mirror_init_disk(struct g_mirror_softc *sc, struct g_provider *pp,
439     struct g_mirror_metadata *md, int *errorp)
440 {
441 	struct g_mirror_disk *disk;
442 	int i, error;
443 
444 	disk = malloc(sizeof(*disk), M_MIRROR, M_NOWAIT | M_ZERO);
445 	if (disk == NULL) {
446 		error = ENOMEM;
447 		goto fail;
448 	}
449 	disk->d_softc = sc;
450 	error = g_mirror_connect_disk(disk, pp);
451 	if (error != 0)
452 		goto fail;
453 	disk->d_id = md->md_did;
454 	disk->d_state = G_MIRROR_DISK_STATE_NONE;
455 	disk->d_priority = md->md_priority;
456 	disk->d_flags = md->md_dflags;
457 	error = g_getattr("GEOM::candelete", disk->d_consumer, &i);
458 	if (error == 0 && i != 0)
459 		disk->d_flags |= G_MIRROR_DISK_FLAG_CANDELETE;
460 	if (md->md_provider[0] != '\0')
461 		disk->d_flags |= G_MIRROR_DISK_FLAG_HARDCODED;
462 	disk->d_sync.ds_consumer = NULL;
463 	disk->d_sync.ds_offset = md->md_sync_offset;
464 	disk->d_sync.ds_offset_done = md->md_sync_offset;
465 	disk->d_genid = md->md_genid;
466 	disk->d_sync.ds_syncid = md->md_syncid;
467 	if (errorp != NULL)
468 		*errorp = 0;
469 	return (disk);
470 fail:
471 	if (errorp != NULL)
472 		*errorp = error;
473 	if (disk != NULL)
474 		free(disk, M_MIRROR);
475 	return (NULL);
476 }
477 
478 static void
479 g_mirror_destroy_disk(struct g_mirror_disk *disk)
480 {
481 	struct g_mirror_softc *sc;
482 
483 	g_topology_assert_not();
484 	sc = disk->d_softc;
485 	sx_assert(&sc->sc_lock, SX_XLOCKED);
486 
487 	LIST_REMOVE(disk, d_next);
488 	g_mirror_event_cancel(disk);
489 	if (sc->sc_hint == disk)
490 		sc->sc_hint = NULL;
491 	switch (disk->d_state) {
492 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
493 		g_mirror_sync_stop(disk, 1);
494 		/* FALLTHROUGH */
495 	case G_MIRROR_DISK_STATE_NEW:
496 	case G_MIRROR_DISK_STATE_STALE:
497 	case G_MIRROR_DISK_STATE_ACTIVE:
498 		g_topology_lock();
499 		g_mirror_disconnect_consumer(sc, disk->d_consumer);
500 		g_topology_unlock();
501 		free(disk, M_MIRROR);
502 		break;
503 	default:
504 		KASSERT(0 == 1, ("Wrong disk state (%s, %s).",
505 		    g_mirror_get_diskname(disk),
506 		    g_mirror_disk_state2str(disk->d_state)));
507 	}
508 }
509 
510 static void
511 g_mirror_destroy_device(struct g_mirror_softc *sc)
512 {
513 	struct g_mirror_disk *disk;
514 	struct g_mirror_event *ep;
515 	struct g_geom *gp;
516 	struct g_consumer *cp, *tmpcp;
517 
518 	g_topology_assert_not();
519 	sx_assert(&sc->sc_lock, SX_XLOCKED);
520 
521 	gp = sc->sc_geom;
522 	if (sc->sc_provider != NULL)
523 		g_mirror_destroy_provider(sc);
524 	for (disk = LIST_FIRST(&sc->sc_disks); disk != NULL;
525 	    disk = LIST_FIRST(&sc->sc_disks)) {
526 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
527 		g_mirror_update_metadata(disk);
528 		g_mirror_destroy_disk(disk);
529 	}
530 	while ((ep = g_mirror_event_get(sc)) != NULL) {
531 		g_mirror_event_remove(sc, ep);
532 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
533 			g_mirror_event_free(ep);
534 		else {
535 			ep->e_error = ECANCELED;
536 			ep->e_flags |= G_MIRROR_EVENT_DONE;
537 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, ep);
538 			mtx_lock(&sc->sc_events_mtx);
539 			wakeup(ep);
540 			mtx_unlock(&sc->sc_events_mtx);
541 		}
542 	}
543 	callout_drain(&sc->sc_callout);
544 
545 	g_topology_lock();
546 	LIST_FOREACH_SAFE(cp, &sc->sc_sync.ds_geom->consumer, consumer, tmpcp) {
547 		g_mirror_disconnect_consumer(sc, cp);
548 	}
549 	g_wither_geom(sc->sc_sync.ds_geom, ENXIO);
550 	G_MIRROR_DEBUG(0, "Device %s destroyed.", gp->name);
551 	g_wither_geom(gp, ENXIO);
552 	g_topology_unlock();
553 	mtx_destroy(&sc->sc_queue_mtx);
554 	mtx_destroy(&sc->sc_events_mtx);
555 	mtx_destroy(&sc->sc_done_mtx);
556 	sx_xunlock(&sc->sc_lock);
557 	sx_destroy(&sc->sc_lock);
558 }
559 
560 static void
561 g_mirror_orphan(struct g_consumer *cp)
562 {
563 	struct g_mirror_disk *disk;
564 
565 	g_topology_assert();
566 
567 	disk = cp->private;
568 	if (disk == NULL)
569 		return;
570 	disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
571 	g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
572 	    G_MIRROR_EVENT_DONTWAIT);
573 }
574 
575 /*
576  * Function should return the next active disk on the list.
577  * It is possible that it will be the same disk as given.
578  * If there are no active disks on list, NULL is returned.
579  */
580 static __inline struct g_mirror_disk *
581 g_mirror_find_next(struct g_mirror_softc *sc, struct g_mirror_disk *disk)
582 {
583 	struct g_mirror_disk *dp;
584 
585 	for (dp = LIST_NEXT(disk, d_next); dp != disk;
586 	    dp = LIST_NEXT(dp, d_next)) {
587 		if (dp == NULL)
588 			dp = LIST_FIRST(&sc->sc_disks);
589 		if (dp->d_state == G_MIRROR_DISK_STATE_ACTIVE)
590 			break;
591 	}
592 	if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
593 		return (NULL);
594 	return (dp);
595 }
596 
597 static struct g_mirror_disk *
598 g_mirror_get_disk(struct g_mirror_softc *sc)
599 {
600 	struct g_mirror_disk *disk;
601 
602 	if (sc->sc_hint == NULL) {
603 		sc->sc_hint = LIST_FIRST(&sc->sc_disks);
604 		if (sc->sc_hint == NULL)
605 			return (NULL);
606 	}
607 	disk = sc->sc_hint;
608 	if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE) {
609 		disk = g_mirror_find_next(sc, disk);
610 		if (disk == NULL)
611 			return (NULL);
612 	}
613 	sc->sc_hint = g_mirror_find_next(sc, disk);
614 	return (disk);
615 }
616 
617 static int
618 g_mirror_write_metadata(struct g_mirror_disk *disk,
619     struct g_mirror_metadata *md)
620 {
621 	struct g_mirror_softc *sc;
622 	struct g_consumer *cp;
623 	off_t offset, length;
624 	u_char *sector;
625 	int error = 0;
626 
627 	g_topology_assert_not();
628 	sc = disk->d_softc;
629 	sx_assert(&sc->sc_lock, SX_LOCKED);
630 
631 	cp = disk->d_consumer;
632 	KASSERT(cp != NULL, ("NULL consumer (%s).", sc->sc_name));
633 	KASSERT(cp->provider != NULL, ("NULL provider (%s).", sc->sc_name));
634 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
635 	    ("Consumer %s closed? (r%dw%de%d).", cp->provider->name, cp->acr,
636 	    cp->acw, cp->ace));
637 	length = cp->provider->sectorsize;
638 	offset = cp->provider->mediasize - length;
639 	sector = malloc((size_t)length, M_MIRROR, M_WAITOK | M_ZERO);
640 	if (md != NULL &&
641 	    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_WIPE) == 0) {
642 		/*
643 		 * Handle the case, when the size of parent provider reduced.
644 		 */
645 		if (offset < md->md_mediasize)
646 			error = ENOSPC;
647 		else
648 			mirror_metadata_encode(md, sector);
649 	}
650 	KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_metadata_write, error);
651 	if (error == 0)
652 		error = g_write_data(cp, offset, sector, length);
653 	free(sector, M_MIRROR);
654 	if (error != 0) {
655 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_BROKEN) == 0) {
656 			disk->d_flags |= G_MIRROR_DISK_FLAG_BROKEN;
657 			G_MIRROR_DEBUG(0, "Cannot write metadata on %s "
658 			    "(device=%s, error=%d).",
659 			    g_mirror_get_diskname(disk), sc->sc_name, error);
660 		} else {
661 			G_MIRROR_DEBUG(1, "Cannot write metadata on %s "
662 			    "(device=%s, error=%d).",
663 			    g_mirror_get_diskname(disk), sc->sc_name, error);
664 		}
665 		if (g_mirror_disconnect_on_failure &&
666 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 1) {
667 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
668 			g_mirror_event_send(disk,
669 			    G_MIRROR_DISK_STATE_DISCONNECTED,
670 			    G_MIRROR_EVENT_DONTWAIT);
671 		}
672 	}
673 	return (error);
674 }
675 
676 static int
677 g_mirror_clear_metadata(struct g_mirror_disk *disk)
678 {
679 	int error;
680 
681 	g_topology_assert_not();
682 	sx_assert(&disk->d_softc->sc_lock, SX_LOCKED);
683 
684 	error = g_mirror_write_metadata(disk, NULL);
685 	if (error == 0) {
686 		G_MIRROR_DEBUG(2, "Metadata on %s cleared.",
687 		    g_mirror_get_diskname(disk));
688 	} else {
689 		G_MIRROR_DEBUG(0,
690 		    "Cannot clear metadata on disk %s (error=%d).",
691 		    g_mirror_get_diskname(disk), error);
692 	}
693 	return (error);
694 }
695 
696 void
697 g_mirror_fill_metadata(struct g_mirror_softc *sc, struct g_mirror_disk *disk,
698     struct g_mirror_metadata *md)
699 {
700 
701 	strlcpy(md->md_magic, G_MIRROR_MAGIC, sizeof(md->md_magic));
702 	md->md_version = G_MIRROR_VERSION;
703 	strlcpy(md->md_name, sc->sc_name, sizeof(md->md_name));
704 	md->md_mid = sc->sc_id;
705 	md->md_all = sc->sc_ndisks;
706 	md->md_slice = sc->sc_slice;
707 	md->md_balance = sc->sc_balance;
708 	md->md_genid = sc->sc_genid;
709 	md->md_mediasize = sc->sc_mediasize;
710 	md->md_sectorsize = sc->sc_sectorsize;
711 	md->md_mflags = (sc->sc_flags & G_MIRROR_DEVICE_FLAG_MASK);
712 	bzero(md->md_provider, sizeof(md->md_provider));
713 	if (disk == NULL) {
714 		md->md_did = arc4random();
715 		md->md_priority = 0;
716 		md->md_syncid = 0;
717 		md->md_dflags = 0;
718 		md->md_sync_offset = 0;
719 		md->md_provsize = 0;
720 	} else {
721 		md->md_did = disk->d_id;
722 		md->md_priority = disk->d_priority;
723 		md->md_syncid = disk->d_sync.ds_syncid;
724 		md->md_dflags = (disk->d_flags & G_MIRROR_DISK_FLAG_MASK);
725 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
726 			md->md_sync_offset = disk->d_sync.ds_offset_done;
727 		else
728 			md->md_sync_offset = 0;
729 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_HARDCODED) != 0) {
730 			strlcpy(md->md_provider,
731 			    disk->d_consumer->provider->name,
732 			    sizeof(md->md_provider));
733 		}
734 		md->md_provsize = disk->d_consumer->provider->mediasize;
735 	}
736 }
737 
738 void
739 g_mirror_update_metadata(struct g_mirror_disk *disk)
740 {
741 	struct g_mirror_softc *sc;
742 	struct g_mirror_metadata md;
743 	int error;
744 
745 	g_topology_assert_not();
746 	sc = disk->d_softc;
747 	sx_assert(&sc->sc_lock, SX_LOCKED);
748 
749 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_WIPE) == 0)
750 		g_mirror_fill_metadata(sc, disk, &md);
751 	error = g_mirror_write_metadata(disk, &md);
752 	if (error == 0) {
753 		G_MIRROR_DEBUG(2, "Metadata on %s updated.",
754 		    g_mirror_get_diskname(disk));
755 	} else {
756 		G_MIRROR_DEBUG(0,
757 		    "Cannot update metadata on disk %s (error=%d).",
758 		    g_mirror_get_diskname(disk), error);
759 	}
760 }
761 
762 static void
763 g_mirror_bump_syncid(struct g_mirror_softc *sc)
764 {
765 	struct g_mirror_disk *disk;
766 
767 	g_topology_assert_not();
768 	sx_assert(&sc->sc_lock, SX_XLOCKED);
769 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
770 	    ("%s called with no active disks (device=%s).", __func__,
771 	    sc->sc_name));
772 
773 	sc->sc_syncid++;
774 	G_MIRROR_DEBUG(1, "Device %s: syncid bumped to %u.", sc->sc_name,
775 	    sc->sc_syncid);
776 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
777 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
778 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
779 			disk->d_sync.ds_syncid = sc->sc_syncid;
780 			g_mirror_update_metadata(disk);
781 		}
782 	}
783 }
784 
785 static void
786 g_mirror_bump_genid(struct g_mirror_softc *sc)
787 {
788 	struct g_mirror_disk *disk;
789 
790 	g_topology_assert_not();
791 	sx_assert(&sc->sc_lock, SX_XLOCKED);
792 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
793 	    ("%s called with no active disks (device=%s).", __func__,
794 	    sc->sc_name));
795 
796 	sc->sc_genid++;
797 	G_MIRROR_DEBUG(1, "Device %s: genid bumped to %u.", sc->sc_name,
798 	    sc->sc_genid);
799 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
800 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
801 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
802 			disk->d_genid = sc->sc_genid;
803 			g_mirror_update_metadata(disk);
804 		}
805 	}
806 }
807 
808 static int
809 g_mirror_idle(struct g_mirror_softc *sc, int acw)
810 {
811 	struct g_mirror_disk *disk;
812 	int timeout;
813 
814 	g_topology_assert_not();
815 	sx_assert(&sc->sc_lock, SX_XLOCKED);
816 
817 	if (sc->sc_provider == NULL)
818 		return (0);
819 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
820 		return (0);
821 	if (sc->sc_idle)
822 		return (0);
823 	if (sc->sc_writes > 0)
824 		return (0);
825 	if (acw > 0 || (acw == -1 && sc->sc_provider->acw > 0)) {
826 		timeout = g_mirror_idletime - (time_uptime - sc->sc_last_write);
827 		if (!g_mirror_shutdown && timeout > 0)
828 			return (timeout);
829 	}
830 	sc->sc_idle = 1;
831 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
832 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
833 			continue;
834 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as clean.",
835 		    g_mirror_get_diskname(disk), sc->sc_name);
836 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
837 		g_mirror_update_metadata(disk);
838 	}
839 	return (0);
840 }
841 
842 static void
843 g_mirror_unidle(struct g_mirror_softc *sc)
844 {
845 	struct g_mirror_disk *disk;
846 
847 	g_topology_assert_not();
848 	sx_assert(&sc->sc_lock, SX_XLOCKED);
849 
850 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
851 		return;
852 	sc->sc_idle = 0;
853 	sc->sc_last_write = time_uptime;
854 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
855 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
856 			continue;
857 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as dirty.",
858 		    g_mirror_get_diskname(disk), sc->sc_name);
859 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
860 		g_mirror_update_metadata(disk);
861 	}
862 }
863 
864 static void
865 g_mirror_flush_done(struct bio *bp)
866 {
867 	struct g_mirror_softc *sc;
868 	struct bio *pbp;
869 
870 	pbp = bp->bio_parent;
871 	sc = pbp->bio_to->geom->softc;
872 	mtx_lock(&sc->sc_done_mtx);
873 	if (pbp->bio_error == 0)
874 		pbp->bio_error = bp->bio_error;
875 	pbp->bio_completed += bp->bio_completed;
876 	pbp->bio_inbed++;
877 	if (pbp->bio_children == pbp->bio_inbed) {
878 		mtx_unlock(&sc->sc_done_mtx);
879 		g_io_deliver(pbp, pbp->bio_error);
880 	} else
881 		mtx_unlock(&sc->sc_done_mtx);
882 	g_destroy_bio(bp);
883 }
884 
885 static void
886 g_mirror_done(struct bio *bp)
887 {
888 	struct g_mirror_softc *sc;
889 
890 	sc = bp->bio_from->geom->softc;
891 	bp->bio_cflags = G_MIRROR_BIO_FLAG_REGULAR;
892 	mtx_lock(&sc->sc_queue_mtx);
893 	bioq_insert_tail(&sc->sc_queue, bp);
894 	mtx_unlock(&sc->sc_queue_mtx);
895 	wakeup(sc);
896 }
897 
898 static void
899 g_mirror_regular_request(struct bio *bp)
900 {
901 	struct g_mirror_softc *sc;
902 	struct g_mirror_disk *disk;
903 	struct bio *pbp;
904 
905 	g_topology_assert_not();
906 
907 	pbp = bp->bio_parent;
908 	sc = pbp->bio_to->geom->softc;
909 	bp->bio_from->index--;
910 	if (bp->bio_cmd == BIO_WRITE)
911 		sc->sc_writes--;
912 	disk = bp->bio_from->private;
913 	if (disk == NULL) {
914 		g_topology_lock();
915 		g_mirror_kill_consumer(sc, bp->bio_from);
916 		g_topology_unlock();
917 	}
918 
919 	if (bp->bio_cmd == BIO_READ)
920 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_regular_request_read,
921 		    bp->bio_error);
922 	else if (bp->bio_cmd == BIO_WRITE)
923 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_regular_request_write,
924 		    bp->bio_error);
925 
926 	pbp->bio_inbed++;
927 	KASSERT(pbp->bio_inbed <= pbp->bio_children,
928 	    ("bio_inbed (%u) is bigger than bio_children (%u).", pbp->bio_inbed,
929 	    pbp->bio_children));
930 	if (bp->bio_error == 0 && pbp->bio_error == 0) {
931 		G_MIRROR_LOGREQ(3, bp, "Request delivered.");
932 		g_destroy_bio(bp);
933 		if (pbp->bio_children == pbp->bio_inbed) {
934 			G_MIRROR_LOGREQ(3, pbp, "Request delivered.");
935 			pbp->bio_completed = pbp->bio_length;
936 			if (pbp->bio_cmd == BIO_WRITE ||
937 			    pbp->bio_cmd == BIO_DELETE) {
938 				bioq_remove(&sc->sc_inflight, pbp);
939 				/* Release delayed sync requests if possible. */
940 				g_mirror_sync_release(sc);
941 			}
942 			g_io_deliver(pbp, pbp->bio_error);
943 		}
944 		return;
945 	} else if (bp->bio_error != 0) {
946 		if (pbp->bio_error == 0)
947 			pbp->bio_error = bp->bio_error;
948 		if (disk != NULL) {
949 			if ((disk->d_flags & G_MIRROR_DISK_FLAG_BROKEN) == 0) {
950 				disk->d_flags |= G_MIRROR_DISK_FLAG_BROKEN;
951 				G_MIRROR_LOGREQ(0, bp,
952 				    "Request failed (error=%d).",
953 				    bp->bio_error);
954 			} else {
955 				G_MIRROR_LOGREQ(1, bp,
956 				    "Request failed (error=%d).",
957 				    bp->bio_error);
958 			}
959 			if (g_mirror_disconnect_on_failure &&
960 			    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 1)
961 			{
962 				sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
963 				g_mirror_event_send(disk,
964 				    G_MIRROR_DISK_STATE_DISCONNECTED,
965 				    G_MIRROR_EVENT_DONTWAIT);
966 			}
967 		}
968 		switch (pbp->bio_cmd) {
969 		case BIO_DELETE:
970 		case BIO_WRITE:
971 			pbp->bio_inbed--;
972 			pbp->bio_children--;
973 			break;
974 		}
975 	}
976 	g_destroy_bio(bp);
977 
978 	switch (pbp->bio_cmd) {
979 	case BIO_READ:
980 		if (pbp->bio_inbed < pbp->bio_children)
981 			break;
982 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 1)
983 			g_io_deliver(pbp, pbp->bio_error);
984 		else {
985 			pbp->bio_error = 0;
986 			mtx_lock(&sc->sc_queue_mtx);
987 			bioq_insert_tail(&sc->sc_queue, pbp);
988 			mtx_unlock(&sc->sc_queue_mtx);
989 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
990 			wakeup(sc);
991 		}
992 		break;
993 	case BIO_DELETE:
994 	case BIO_WRITE:
995 		if (pbp->bio_children == 0) {
996 			/*
997 			 * All requests failed.
998 			 */
999 		} else if (pbp->bio_inbed < pbp->bio_children) {
1000 			/* Do nothing. */
1001 			break;
1002 		} else if (pbp->bio_children == pbp->bio_inbed) {
1003 			/* Some requests succeeded. */
1004 			pbp->bio_error = 0;
1005 			pbp->bio_completed = pbp->bio_length;
1006 		}
1007 		bioq_remove(&sc->sc_inflight, pbp);
1008 		/* Release delayed sync requests if possible. */
1009 		g_mirror_sync_release(sc);
1010 		g_io_deliver(pbp, pbp->bio_error);
1011 		break;
1012 	default:
1013 		KASSERT(1 == 0, ("Invalid request: %u.", pbp->bio_cmd));
1014 		break;
1015 	}
1016 }
1017 
1018 static void
1019 g_mirror_sync_done(struct bio *bp)
1020 {
1021 	struct g_mirror_softc *sc;
1022 
1023 	G_MIRROR_LOGREQ(3, bp, "Synchronization request delivered.");
1024 	sc = bp->bio_from->geom->softc;
1025 	bp->bio_cflags = G_MIRROR_BIO_FLAG_SYNC;
1026 	mtx_lock(&sc->sc_queue_mtx);
1027 	bioq_insert_tail(&sc->sc_queue, bp);
1028 	mtx_unlock(&sc->sc_queue_mtx);
1029 	wakeup(sc);
1030 }
1031 
1032 static void
1033 g_mirror_candelete(struct bio *bp)
1034 {
1035 	struct g_mirror_softc *sc;
1036 	struct g_mirror_disk *disk;
1037 	int *val;
1038 
1039 	sc = bp->bio_to->geom->softc;
1040 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1041 		if (disk->d_flags & G_MIRROR_DISK_FLAG_CANDELETE)
1042 			break;
1043 	}
1044 	val = (int *)bp->bio_data;
1045 	*val = (disk != NULL);
1046 	g_io_deliver(bp, 0);
1047 }
1048 
1049 static void
1050 g_mirror_kernel_dump(struct bio *bp)
1051 {
1052 	struct g_mirror_softc *sc;
1053 	struct g_mirror_disk *disk;
1054 	struct bio *cbp;
1055 	struct g_kerneldump *gkd;
1056 
1057 	/*
1058 	 * We configure dumping to the first component, because this component
1059 	 * will be used for reading with 'prefer' balance algorithm.
1060 	 * If the component with the highest priority is currently disconnected
1061 	 * we will not be able to read the dump after the reboot if it will be
1062 	 * connected and synchronized later. Can we do something better?
1063 	 */
1064 	sc = bp->bio_to->geom->softc;
1065 	disk = LIST_FIRST(&sc->sc_disks);
1066 
1067 	gkd = (struct g_kerneldump *)bp->bio_data;
1068 	if (gkd->length > bp->bio_to->mediasize)
1069 		gkd->length = bp->bio_to->mediasize;
1070 	cbp = g_clone_bio(bp);
1071 	if (cbp == NULL) {
1072 		g_io_deliver(bp, ENOMEM);
1073 		return;
1074 	}
1075 	cbp->bio_done = g_std_done;
1076 	g_io_request(cbp, disk->d_consumer);
1077 	G_MIRROR_DEBUG(1, "Kernel dump will go to %s.",
1078 	    g_mirror_get_diskname(disk));
1079 }
1080 
1081 static void
1082 g_mirror_flush(struct g_mirror_softc *sc, struct bio *bp)
1083 {
1084 	struct bio_queue_head queue;
1085 	struct g_mirror_disk *disk;
1086 	struct g_consumer *cp;
1087 	struct bio *cbp;
1088 
1089 	bioq_init(&queue);
1090 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1091 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1092 			continue;
1093 		cbp = g_clone_bio(bp);
1094 		if (cbp == NULL) {
1095 			while ((cbp = bioq_takefirst(&queue)) != NULL)
1096 				g_destroy_bio(cbp);
1097 			if (bp->bio_error == 0)
1098 				bp->bio_error = ENOMEM;
1099 			g_io_deliver(bp, bp->bio_error);
1100 			return;
1101 		}
1102 		bioq_insert_tail(&queue, cbp);
1103 		cbp->bio_done = g_mirror_flush_done;
1104 		cbp->bio_caller1 = disk;
1105 		cbp->bio_to = disk->d_consumer->provider;
1106 	}
1107 	while ((cbp = bioq_takefirst(&queue)) != NULL) {
1108 		G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1109 		disk = cbp->bio_caller1;
1110 		cbp->bio_caller1 = NULL;
1111 		cp = disk->d_consumer;
1112 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1113 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1114 		    cp->acr, cp->acw, cp->ace));
1115 		g_io_request(cbp, disk->d_consumer);
1116 	}
1117 }
1118 
1119 static void
1120 g_mirror_start(struct bio *bp)
1121 {
1122 	struct g_mirror_softc *sc;
1123 
1124 	sc = bp->bio_to->geom->softc;
1125 	/*
1126 	 * If sc == NULL or there are no valid disks, provider's error
1127 	 * should be set and g_mirror_start() should not be called at all.
1128 	 */
1129 	KASSERT(sc != NULL && sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
1130 	    ("Provider's error should be set (error=%d)(mirror=%s).",
1131 	    bp->bio_to->error, bp->bio_to->name));
1132 	G_MIRROR_LOGREQ(3, bp, "Request received.");
1133 
1134 	switch (bp->bio_cmd) {
1135 	case BIO_READ:
1136 	case BIO_WRITE:
1137 	case BIO_DELETE:
1138 		break;
1139 	case BIO_FLUSH:
1140 		g_mirror_flush(sc, bp);
1141 		return;
1142 	case BIO_GETATTR:
1143 		if (!strcmp(bp->bio_attribute, "GEOM::candelete")) {
1144 			g_mirror_candelete(bp);
1145 			return;
1146 		} else if (strcmp("GEOM::kerneldump", bp->bio_attribute) == 0) {
1147 			g_mirror_kernel_dump(bp);
1148 			return;
1149 		}
1150 		/* FALLTHROUGH */
1151 	default:
1152 		g_io_deliver(bp, EOPNOTSUPP);
1153 		return;
1154 	}
1155 	mtx_lock(&sc->sc_queue_mtx);
1156 	bioq_insert_tail(&sc->sc_queue, bp);
1157 	mtx_unlock(&sc->sc_queue_mtx);
1158 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
1159 	wakeup(sc);
1160 }
1161 
1162 /*
1163  * Return TRUE if the given request is colliding with a in-progress
1164  * synchronization request.
1165  */
1166 static int
1167 g_mirror_sync_collision(struct g_mirror_softc *sc, struct bio *bp)
1168 {
1169 	struct g_mirror_disk *disk;
1170 	struct bio *sbp;
1171 	off_t rstart, rend, sstart, send;
1172 	u_int i;
1173 
1174 	if (sc->sc_sync.ds_ndisks == 0)
1175 		return (0);
1176 	rstart = bp->bio_offset;
1177 	rend = bp->bio_offset + bp->bio_length;
1178 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1179 		if (disk->d_state != G_MIRROR_DISK_STATE_SYNCHRONIZING)
1180 			continue;
1181 		for (i = 0; i < g_mirror_syncreqs; i++) {
1182 			sbp = disk->d_sync.ds_bios[i];
1183 			if (sbp == NULL)
1184 				continue;
1185 			sstart = sbp->bio_offset;
1186 			send = sbp->bio_offset + sbp->bio_length;
1187 			if (rend > sstart && rstart < send)
1188 				return (1);
1189 		}
1190 	}
1191 	return (0);
1192 }
1193 
1194 /*
1195  * Return TRUE if the given sync request is colliding with a in-progress regular
1196  * request.
1197  */
1198 static int
1199 g_mirror_regular_collision(struct g_mirror_softc *sc, struct bio *sbp)
1200 {
1201 	off_t rstart, rend, sstart, send;
1202 	struct bio *bp;
1203 
1204 	if (sc->sc_sync.ds_ndisks == 0)
1205 		return (0);
1206 	sstart = sbp->bio_offset;
1207 	send = sbp->bio_offset + sbp->bio_length;
1208 	TAILQ_FOREACH(bp, &sc->sc_inflight.queue, bio_queue) {
1209 		rstart = bp->bio_offset;
1210 		rend = bp->bio_offset + bp->bio_length;
1211 		if (rend > sstart && rstart < send)
1212 			return (1);
1213 	}
1214 	return (0);
1215 }
1216 
1217 /*
1218  * Puts request onto delayed queue.
1219  */
1220 static void
1221 g_mirror_regular_delay(struct g_mirror_softc *sc, struct bio *bp)
1222 {
1223 
1224 	G_MIRROR_LOGREQ(2, bp, "Delaying request.");
1225 	bioq_insert_head(&sc->sc_regular_delayed, bp);
1226 }
1227 
1228 /*
1229  * Puts synchronization request onto delayed queue.
1230  */
1231 static void
1232 g_mirror_sync_delay(struct g_mirror_softc *sc, struct bio *bp)
1233 {
1234 
1235 	G_MIRROR_LOGREQ(2, bp, "Delaying synchronization request.");
1236 	bioq_insert_tail(&sc->sc_sync_delayed, bp);
1237 }
1238 
1239 /*
1240  * Releases delayed regular requests which don't collide anymore with sync
1241  * requests.
1242  */
1243 static void
1244 g_mirror_regular_release(struct g_mirror_softc *sc)
1245 {
1246 	struct bio *bp, *bp2;
1247 
1248 	TAILQ_FOREACH_SAFE(bp, &sc->sc_regular_delayed.queue, bio_queue, bp2) {
1249 		if (g_mirror_sync_collision(sc, bp))
1250 			continue;
1251 		bioq_remove(&sc->sc_regular_delayed, bp);
1252 		G_MIRROR_LOGREQ(2, bp, "Releasing delayed request (%p).", bp);
1253 		mtx_lock(&sc->sc_queue_mtx);
1254 		bioq_insert_head(&sc->sc_queue, bp);
1255 #if 0
1256 		/*
1257 		 * wakeup() is not needed, because this function is called from
1258 		 * the worker thread.
1259 		 */
1260 		wakeup(&sc->sc_queue);
1261 #endif
1262 		mtx_unlock(&sc->sc_queue_mtx);
1263 	}
1264 }
1265 
1266 /*
1267  * Releases delayed sync requests which don't collide anymore with regular
1268  * requests.
1269  */
1270 static void
1271 g_mirror_sync_release(struct g_mirror_softc *sc)
1272 {
1273 	struct bio *bp, *bp2;
1274 
1275 	TAILQ_FOREACH_SAFE(bp, &sc->sc_sync_delayed.queue, bio_queue, bp2) {
1276 		if (g_mirror_regular_collision(sc, bp))
1277 			continue;
1278 		bioq_remove(&sc->sc_sync_delayed, bp);
1279 		G_MIRROR_LOGREQ(2, bp,
1280 		    "Releasing delayed synchronization request.");
1281 		g_io_request(bp, bp->bio_from);
1282 	}
1283 }
1284 
1285 /*
1286  * Handle synchronization requests.
1287  * Every synchronization request is two-steps process: first, READ request is
1288  * send to active provider and then WRITE request (with read data) to the provider
1289  * being synchronized. When WRITE is finished, new synchronization request is
1290  * send.
1291  */
1292 static void
1293 g_mirror_sync_request(struct bio *bp)
1294 {
1295 	struct g_mirror_softc *sc;
1296 	struct g_mirror_disk *disk;
1297 
1298 	bp->bio_from->index--;
1299 	sc = bp->bio_from->geom->softc;
1300 	disk = bp->bio_from->private;
1301 	if (disk == NULL) {
1302 		sx_xunlock(&sc->sc_lock); /* Avoid recursion on sc_lock. */
1303 		g_topology_lock();
1304 		g_mirror_kill_consumer(sc, bp->bio_from);
1305 		g_topology_unlock();
1306 		free(bp->bio_data, M_MIRROR);
1307 		g_destroy_bio(bp);
1308 		sx_xlock(&sc->sc_lock);
1309 		return;
1310 	}
1311 
1312 	/*
1313 	 * Synchronization request.
1314 	 */
1315 	switch (bp->bio_cmd) {
1316 	case BIO_READ:
1317 	    {
1318 		struct g_consumer *cp;
1319 
1320 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_sync_request_read,
1321 		    bp->bio_error);
1322 
1323 		if (bp->bio_error != 0) {
1324 			G_MIRROR_LOGREQ(0, bp,
1325 			    "Synchronization request failed (error=%d).",
1326 			    bp->bio_error);
1327 			g_destroy_bio(bp);
1328 			return;
1329 		}
1330 		G_MIRROR_LOGREQ(3, bp,
1331 		    "Synchronization request half-finished.");
1332 		bp->bio_cmd = BIO_WRITE;
1333 		bp->bio_cflags = 0;
1334 		cp = disk->d_consumer;
1335 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1336 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1337 		    cp->acr, cp->acw, cp->ace));
1338 		cp->index++;
1339 		g_io_request(bp, cp);
1340 		return;
1341 	    }
1342 	case BIO_WRITE:
1343 	    {
1344 		struct g_mirror_disk_sync *sync;
1345 		off_t offset;
1346 		void *data;
1347 		int i;
1348 
1349 		KFAIL_POINT_ERROR(DEBUG_FP, g_mirror_sync_request_write,
1350 		    bp->bio_error);
1351 
1352 		if (bp->bio_error != 0) {
1353 			G_MIRROR_LOGREQ(0, bp,
1354 			    "Synchronization request failed (error=%d).",
1355 			    bp->bio_error);
1356 			g_destroy_bio(bp);
1357 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
1358 			g_mirror_event_send(disk,
1359 			    G_MIRROR_DISK_STATE_DISCONNECTED,
1360 			    G_MIRROR_EVENT_DONTWAIT);
1361 			return;
1362 		}
1363 		G_MIRROR_LOGREQ(3, bp, "Synchronization request finished.");
1364 		sync = &disk->d_sync;
1365 		if (sync->ds_offset >= sc->sc_mediasize ||
1366 		    sync->ds_consumer == NULL ||
1367 		    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1368 			/* Don't send more synchronization requests. */
1369 			sync->ds_inflight--;
1370 			if (sync->ds_bios != NULL) {
1371 				i = (int)(uintptr_t)bp->bio_caller1;
1372 				sync->ds_bios[i] = NULL;
1373 			}
1374 			free(bp->bio_data, M_MIRROR);
1375 			g_destroy_bio(bp);
1376 			if (sync->ds_inflight > 0)
1377 				return;
1378 			if (sync->ds_consumer == NULL ||
1379 			    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1380 				return;
1381 			}
1382 			/* Disk up-to-date, activate it. */
1383 			g_mirror_event_send(disk, G_MIRROR_DISK_STATE_ACTIVE,
1384 			    G_MIRROR_EVENT_DONTWAIT);
1385 			return;
1386 		}
1387 
1388 		/* Send next synchronization request. */
1389 		data = bp->bio_data;
1390 		g_reset_bio(bp);
1391 		bp->bio_cmd = BIO_READ;
1392 		bp->bio_offset = sync->ds_offset;
1393 		bp->bio_length = MIN(MAXPHYS, sc->sc_mediasize - bp->bio_offset);
1394 		sync->ds_offset += bp->bio_length;
1395 		bp->bio_done = g_mirror_sync_done;
1396 		bp->bio_data = data;
1397 		bp->bio_from = sync->ds_consumer;
1398 		bp->bio_to = sc->sc_provider;
1399 		G_MIRROR_LOGREQ(3, bp, "Sending synchronization request.");
1400 		sync->ds_consumer->index++;
1401 		/*
1402 		 * Delay the request if it is colliding with a regular request.
1403 		 */
1404 		if (g_mirror_regular_collision(sc, bp))
1405 			g_mirror_sync_delay(sc, bp);
1406 		else
1407 			g_io_request(bp, sync->ds_consumer);
1408 
1409 		/* Release delayed requests if possible. */
1410 		g_mirror_regular_release(sc);
1411 
1412 		/* Find the smallest offset */
1413 		offset = sc->sc_mediasize;
1414 		for (i = 0; i < g_mirror_syncreqs; i++) {
1415 			bp = sync->ds_bios[i];
1416 			if (bp->bio_offset < offset)
1417 				offset = bp->bio_offset;
1418 		}
1419 		if (sync->ds_offset_done + (MAXPHYS * 100) < offset) {
1420 			/* Update offset_done on every 100 blocks. */
1421 			sync->ds_offset_done = offset;
1422 			g_mirror_update_metadata(disk);
1423 		}
1424 		return;
1425 	    }
1426 	default:
1427 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1428 		    bp->bio_cmd, sc->sc_name));
1429 		break;
1430 	}
1431 }
1432 
1433 static void
1434 g_mirror_request_prefer(struct g_mirror_softc *sc, struct bio *bp)
1435 {
1436 	struct g_mirror_disk *disk;
1437 	struct g_consumer *cp;
1438 	struct bio *cbp;
1439 
1440 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1441 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE)
1442 			break;
1443 	}
1444 	if (disk == NULL) {
1445 		if (bp->bio_error == 0)
1446 			bp->bio_error = ENXIO;
1447 		g_io_deliver(bp, bp->bio_error);
1448 		return;
1449 	}
1450 	cbp = g_clone_bio(bp);
1451 	if (cbp == NULL) {
1452 		if (bp->bio_error == 0)
1453 			bp->bio_error = ENOMEM;
1454 		g_io_deliver(bp, bp->bio_error);
1455 		return;
1456 	}
1457 	/*
1458 	 * Fill in the component buf structure.
1459 	 */
1460 	cp = disk->d_consumer;
1461 	cbp->bio_done = g_mirror_done;
1462 	cbp->bio_to = cp->provider;
1463 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1464 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1465 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1466 	    cp->acw, cp->ace));
1467 	cp->index++;
1468 	g_io_request(cbp, cp);
1469 }
1470 
1471 static void
1472 g_mirror_request_round_robin(struct g_mirror_softc *sc, struct bio *bp)
1473 {
1474 	struct g_mirror_disk *disk;
1475 	struct g_consumer *cp;
1476 	struct bio *cbp;
1477 
1478 	disk = g_mirror_get_disk(sc);
1479 	if (disk == NULL) {
1480 		if (bp->bio_error == 0)
1481 			bp->bio_error = ENXIO;
1482 		g_io_deliver(bp, bp->bio_error);
1483 		return;
1484 	}
1485 	cbp = g_clone_bio(bp);
1486 	if (cbp == NULL) {
1487 		if (bp->bio_error == 0)
1488 			bp->bio_error = ENOMEM;
1489 		g_io_deliver(bp, bp->bio_error);
1490 		return;
1491 	}
1492 	/*
1493 	 * Fill in the component buf structure.
1494 	 */
1495 	cp = disk->d_consumer;
1496 	cbp->bio_done = g_mirror_done;
1497 	cbp->bio_to = cp->provider;
1498 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1499 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1500 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1501 	    cp->acw, cp->ace));
1502 	cp->index++;
1503 	g_io_request(cbp, cp);
1504 }
1505 
1506 #define TRACK_SIZE  (1 * 1024 * 1024)
1507 #define LOAD_SCALE	256
1508 #define ABS(x)		(((x) >= 0) ? (x) : (-(x)))
1509 
1510 static void
1511 g_mirror_request_load(struct g_mirror_softc *sc, struct bio *bp)
1512 {
1513 	struct g_mirror_disk *disk, *dp;
1514 	struct g_consumer *cp;
1515 	struct bio *cbp;
1516 	int prio, best;
1517 
1518 	/* Find a disk with the smallest load. */
1519 	disk = NULL;
1520 	best = INT_MAX;
1521 	LIST_FOREACH(dp, &sc->sc_disks, d_next) {
1522 		if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1523 			continue;
1524 		prio = dp->load;
1525 		/* If disk head is precisely in position - highly prefer it. */
1526 		if (dp->d_last_offset == bp->bio_offset)
1527 			prio -= 2 * LOAD_SCALE;
1528 		else
1529 		/* If disk head is close to position - prefer it. */
1530 		if (ABS(dp->d_last_offset - bp->bio_offset) < TRACK_SIZE)
1531 			prio -= 1 * LOAD_SCALE;
1532 		if (prio <= best) {
1533 			disk = dp;
1534 			best = prio;
1535 		}
1536 	}
1537 	KASSERT(disk != NULL, ("NULL disk for %s.", sc->sc_name));
1538 	cbp = g_clone_bio(bp);
1539 	if (cbp == NULL) {
1540 		if (bp->bio_error == 0)
1541 			bp->bio_error = ENOMEM;
1542 		g_io_deliver(bp, bp->bio_error);
1543 		return;
1544 	}
1545 	/*
1546 	 * Fill in the component buf structure.
1547 	 */
1548 	cp = disk->d_consumer;
1549 	cbp->bio_done = g_mirror_done;
1550 	cbp->bio_to = cp->provider;
1551 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1552 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1553 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1554 	    cp->acw, cp->ace));
1555 	cp->index++;
1556 	/* Remember last head position */
1557 	disk->d_last_offset = bp->bio_offset + bp->bio_length;
1558 	/* Update loads. */
1559 	LIST_FOREACH(dp, &sc->sc_disks, d_next) {
1560 		dp->load = (dp->d_consumer->index * LOAD_SCALE +
1561 		    dp->load * 7) / 8;
1562 	}
1563 	g_io_request(cbp, cp);
1564 }
1565 
1566 static void
1567 g_mirror_request_split(struct g_mirror_softc *sc, struct bio *bp)
1568 {
1569 	struct bio_queue_head queue;
1570 	struct g_mirror_disk *disk;
1571 	struct g_consumer *cp;
1572 	struct bio *cbp;
1573 	off_t left, mod, offset, slice;
1574 	u_char *data;
1575 	u_int ndisks;
1576 
1577 	if (bp->bio_length <= sc->sc_slice) {
1578 		g_mirror_request_round_robin(sc, bp);
1579 		return;
1580 	}
1581 	ndisks = g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE);
1582 	slice = bp->bio_length / ndisks;
1583 	mod = slice % sc->sc_provider->sectorsize;
1584 	if (mod != 0)
1585 		slice += sc->sc_provider->sectorsize - mod;
1586 	/*
1587 	 * Allocate all bios before sending any request, so we can
1588 	 * return ENOMEM in nice and clean way.
1589 	 */
1590 	left = bp->bio_length;
1591 	offset = bp->bio_offset;
1592 	data = bp->bio_data;
1593 	bioq_init(&queue);
1594 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1595 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1596 			continue;
1597 		cbp = g_clone_bio(bp);
1598 		if (cbp == NULL) {
1599 			while ((cbp = bioq_takefirst(&queue)) != NULL)
1600 				g_destroy_bio(cbp);
1601 			if (bp->bio_error == 0)
1602 				bp->bio_error = ENOMEM;
1603 			g_io_deliver(bp, bp->bio_error);
1604 			return;
1605 		}
1606 		bioq_insert_tail(&queue, cbp);
1607 		cbp->bio_done = g_mirror_done;
1608 		cbp->bio_caller1 = disk;
1609 		cbp->bio_to = disk->d_consumer->provider;
1610 		cbp->bio_offset = offset;
1611 		cbp->bio_data = data;
1612 		cbp->bio_length = MIN(left, slice);
1613 		left -= cbp->bio_length;
1614 		if (left == 0)
1615 			break;
1616 		offset += cbp->bio_length;
1617 		data += cbp->bio_length;
1618 	}
1619 	while ((cbp = bioq_takefirst(&queue)) != NULL) {
1620 		G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1621 		disk = cbp->bio_caller1;
1622 		cbp->bio_caller1 = NULL;
1623 		cp = disk->d_consumer;
1624 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1625 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1626 		    cp->acr, cp->acw, cp->ace));
1627 		disk->d_consumer->index++;
1628 		g_io_request(cbp, disk->d_consumer);
1629 	}
1630 }
1631 
1632 static void
1633 g_mirror_register_request(struct bio *bp)
1634 {
1635 	struct g_mirror_softc *sc;
1636 
1637 	sc = bp->bio_to->geom->softc;
1638 	switch (bp->bio_cmd) {
1639 	case BIO_READ:
1640 		switch (sc->sc_balance) {
1641 		case G_MIRROR_BALANCE_LOAD:
1642 			g_mirror_request_load(sc, bp);
1643 			break;
1644 		case G_MIRROR_BALANCE_PREFER:
1645 			g_mirror_request_prefer(sc, bp);
1646 			break;
1647 		case G_MIRROR_BALANCE_ROUND_ROBIN:
1648 			g_mirror_request_round_robin(sc, bp);
1649 			break;
1650 		case G_MIRROR_BALANCE_SPLIT:
1651 			g_mirror_request_split(sc, bp);
1652 			break;
1653 		}
1654 		return;
1655 	case BIO_WRITE:
1656 	case BIO_DELETE:
1657 	    {
1658 		struct g_mirror_disk *disk;
1659 		struct g_mirror_disk_sync *sync;
1660 		struct bio_queue_head queue;
1661 		struct g_consumer *cp;
1662 		struct bio *cbp;
1663 
1664 		/*
1665 		 * Delay the request if it is colliding with a synchronization
1666 		 * request.
1667 		 */
1668 		if (g_mirror_sync_collision(sc, bp)) {
1669 			g_mirror_regular_delay(sc, bp);
1670 			return;
1671 		}
1672 
1673 		if (sc->sc_idle)
1674 			g_mirror_unidle(sc);
1675 		else
1676 			sc->sc_last_write = time_uptime;
1677 
1678 		/*
1679 		 * Allocate all bios before sending any request, so we can
1680 		 * return ENOMEM in nice and clean way.
1681 		 */
1682 		bioq_init(&queue);
1683 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1684 			sync = &disk->d_sync;
1685 			switch (disk->d_state) {
1686 			case G_MIRROR_DISK_STATE_ACTIVE:
1687 				break;
1688 			case G_MIRROR_DISK_STATE_SYNCHRONIZING:
1689 				if (bp->bio_offset >= sync->ds_offset)
1690 					continue;
1691 				break;
1692 			default:
1693 				continue;
1694 			}
1695 			if (bp->bio_cmd == BIO_DELETE &&
1696 			    (disk->d_flags & G_MIRROR_DISK_FLAG_CANDELETE) == 0)
1697 				continue;
1698 			cbp = g_clone_bio(bp);
1699 			if (cbp == NULL) {
1700 				while ((cbp = bioq_takefirst(&queue)) != NULL)
1701 					g_destroy_bio(cbp);
1702 				if (bp->bio_error == 0)
1703 					bp->bio_error = ENOMEM;
1704 				g_io_deliver(bp, bp->bio_error);
1705 				return;
1706 			}
1707 			bioq_insert_tail(&queue, cbp);
1708 			cbp->bio_done = g_mirror_done;
1709 			cp = disk->d_consumer;
1710 			cbp->bio_caller1 = cp;
1711 			cbp->bio_to = cp->provider;
1712 			KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1713 			    ("Consumer %s not opened (r%dw%de%d).",
1714 			    cp->provider->name, cp->acr, cp->acw, cp->ace));
1715 		}
1716 		if (bioq_first(&queue) == NULL) {
1717 			g_io_deliver(bp, EOPNOTSUPP);
1718 			return;
1719 		}
1720 		while ((cbp = bioq_takefirst(&queue)) != NULL) {
1721 			G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1722 			cp = cbp->bio_caller1;
1723 			cbp->bio_caller1 = NULL;
1724 			cp->index++;
1725 			sc->sc_writes++;
1726 			g_io_request(cbp, cp);
1727 		}
1728 		/*
1729 		 * Put request onto inflight queue, so we can check if new
1730 		 * synchronization requests don't collide with it.
1731 		 */
1732 		bioq_insert_tail(&sc->sc_inflight, bp);
1733 		/*
1734 		 * Bump syncid on first write.
1735 		 */
1736 		if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0) {
1737 			sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
1738 			g_mirror_bump_syncid(sc);
1739 		}
1740 		return;
1741 	    }
1742 	default:
1743 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1744 		    bp->bio_cmd, sc->sc_name));
1745 		break;
1746 	}
1747 }
1748 
1749 static int
1750 g_mirror_can_destroy(struct g_mirror_softc *sc)
1751 {
1752 	struct g_geom *gp;
1753 	struct g_consumer *cp;
1754 
1755 	g_topology_assert();
1756 	gp = sc->sc_geom;
1757 	if (gp->softc == NULL)
1758 		return (1);
1759 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_TASTING) != 0)
1760 		return (0);
1761 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1762 		if (g_mirror_is_busy(sc, cp))
1763 			return (0);
1764 	}
1765 	gp = sc->sc_sync.ds_geom;
1766 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1767 		if (g_mirror_is_busy(sc, cp))
1768 			return (0);
1769 	}
1770 	G_MIRROR_DEBUG(2, "No I/O requests for %s, it can be destroyed.",
1771 	    sc->sc_name);
1772 	return (1);
1773 }
1774 
1775 static int
1776 g_mirror_try_destroy(struct g_mirror_softc *sc)
1777 {
1778 
1779 	if (sc->sc_rootmount != NULL) {
1780 		G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p", __LINE__,
1781 		    sc->sc_rootmount);
1782 		root_mount_rel(sc->sc_rootmount);
1783 		sc->sc_rootmount = NULL;
1784 	}
1785 	g_topology_lock();
1786 	if (!g_mirror_can_destroy(sc)) {
1787 		g_topology_unlock();
1788 		return (0);
1789 	}
1790 	sc->sc_geom->softc = NULL;
1791 	sc->sc_sync.ds_geom->softc = NULL;
1792 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_WAIT) != 0) {
1793 		g_topology_unlock();
1794 		G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1795 		    &sc->sc_worker);
1796 		/* Unlock sc_lock here, as it can be destroyed after wakeup. */
1797 		sx_xunlock(&sc->sc_lock);
1798 		wakeup(&sc->sc_worker);
1799 		sc->sc_worker = NULL;
1800 	} else {
1801 		g_topology_unlock();
1802 		g_mirror_destroy_device(sc);
1803 		free(sc, M_MIRROR);
1804 	}
1805 	return (1);
1806 }
1807 
1808 /*
1809  * Worker thread.
1810  */
1811 static void
1812 g_mirror_worker(void *arg)
1813 {
1814 	struct g_mirror_softc *sc;
1815 	struct g_mirror_event *ep;
1816 	struct bio *bp;
1817 	int timeout;
1818 
1819 	sc = arg;
1820 	thread_lock(curthread);
1821 	sched_prio(curthread, PRIBIO);
1822 	thread_unlock(curthread);
1823 
1824 	sx_xlock(&sc->sc_lock);
1825 	for (;;) {
1826 		G_MIRROR_DEBUG(5, "%s: Let's see...", __func__);
1827 		/*
1828 		 * First take a look at events.
1829 		 * This is important to handle events before any I/O requests.
1830 		 */
1831 		ep = g_mirror_event_get(sc);
1832 		if (ep != NULL) {
1833 			g_mirror_event_remove(sc, ep);
1834 			if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0) {
1835 				/* Update only device status. */
1836 				G_MIRROR_DEBUG(3,
1837 				    "Running event for device %s.",
1838 				    sc->sc_name);
1839 				ep->e_error = 0;
1840 				g_mirror_update_device(sc, 1);
1841 			} else {
1842 				/* Update disk status. */
1843 				G_MIRROR_DEBUG(3, "Running event for disk %s.",
1844 				     g_mirror_get_diskname(ep->e_disk));
1845 				ep->e_error = g_mirror_update_disk(ep->e_disk,
1846 				    ep->e_state);
1847 				if (ep->e_error == 0)
1848 					g_mirror_update_device(sc, 0);
1849 			}
1850 			if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0) {
1851 				KASSERT(ep->e_error == 0,
1852 				    ("Error cannot be handled."));
1853 				g_mirror_event_free(ep);
1854 			} else {
1855 				ep->e_flags |= G_MIRROR_EVENT_DONE;
1856 				G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1857 				    ep);
1858 				mtx_lock(&sc->sc_events_mtx);
1859 				wakeup(ep);
1860 				mtx_unlock(&sc->sc_events_mtx);
1861 			}
1862 			if ((sc->sc_flags &
1863 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1864 				if (g_mirror_try_destroy(sc)) {
1865 					curthread->td_pflags &= ~TDP_GEOM;
1866 					G_MIRROR_DEBUG(1, "Thread exiting.");
1867 					kproc_exit(0);
1868 				}
1869 			}
1870 			G_MIRROR_DEBUG(5, "%s: I'm here 1.", __func__);
1871 			continue;
1872 		}
1873 		/*
1874 		 * Check if we can mark array as CLEAN and if we can't take
1875 		 * how much seconds should we wait.
1876 		 */
1877 		timeout = g_mirror_idle(sc, -1);
1878 		/*
1879 		 * Now I/O requests.
1880 		 */
1881 		/* Get first request from the queue. */
1882 		mtx_lock(&sc->sc_queue_mtx);
1883 		bp = bioq_takefirst(&sc->sc_queue);
1884 		if (bp == NULL) {
1885 			if ((sc->sc_flags &
1886 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1887 				mtx_unlock(&sc->sc_queue_mtx);
1888 				if (g_mirror_try_destroy(sc)) {
1889 					curthread->td_pflags &= ~TDP_GEOM;
1890 					G_MIRROR_DEBUG(1, "Thread exiting.");
1891 					kproc_exit(0);
1892 				}
1893 				mtx_lock(&sc->sc_queue_mtx);
1894 			}
1895 			sx_xunlock(&sc->sc_lock);
1896 			/*
1897 			 * XXX: We can miss an event here, because an event
1898 			 *      can be added without sx-device-lock and without
1899 			 *      mtx-queue-lock. Maybe I should just stop using
1900 			 *      dedicated mutex for events synchronization and
1901 			 *      stick with the queue lock?
1902 			 *      The event will hang here until next I/O request
1903 			 *      or next event is received.
1904 			 */
1905 			MSLEEP(sc, &sc->sc_queue_mtx, PRIBIO | PDROP, "m:w1",
1906 			    timeout * hz);
1907 			sx_xlock(&sc->sc_lock);
1908 			G_MIRROR_DEBUG(5, "%s: I'm here 4.", __func__);
1909 			continue;
1910 		}
1911 		mtx_unlock(&sc->sc_queue_mtx);
1912 
1913 		if (bp->bio_from->geom == sc->sc_sync.ds_geom &&
1914 		    (bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0) {
1915 			g_mirror_sync_request(bp);	/* READ */
1916 		} else if (bp->bio_to != sc->sc_provider) {
1917 			if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_REGULAR) != 0)
1918 				g_mirror_regular_request(bp);
1919 			else if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0)
1920 				g_mirror_sync_request(bp);	/* WRITE */
1921 			else {
1922 				KASSERT(0,
1923 				    ("Invalid request cflags=0x%hx to=%s.",
1924 				    bp->bio_cflags, bp->bio_to->name));
1925 			}
1926 		} else {
1927 			g_mirror_register_request(bp);
1928 		}
1929 		G_MIRROR_DEBUG(5, "%s: I'm here 9.", __func__);
1930 	}
1931 }
1932 
1933 static void
1934 g_mirror_update_idle(struct g_mirror_softc *sc, struct g_mirror_disk *disk)
1935 {
1936 
1937 	sx_assert(&sc->sc_lock, SX_LOCKED);
1938 
1939 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
1940 		return;
1941 	if (!sc->sc_idle && (disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) == 0) {
1942 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as dirty.",
1943 		    g_mirror_get_diskname(disk), sc->sc_name);
1944 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1945 	} else if (sc->sc_idle &&
1946 	    (disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
1947 		G_MIRROR_DEBUG(2, "Disk %s (device %s) marked as clean.",
1948 		    g_mirror_get_diskname(disk), sc->sc_name);
1949 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
1950 	}
1951 }
1952 
1953 static void
1954 g_mirror_sync_start(struct g_mirror_disk *disk)
1955 {
1956 	struct g_mirror_softc *sc;
1957 	struct g_consumer *cp;
1958 	struct bio *bp;
1959 	int error, i;
1960 
1961 	g_topology_assert_not();
1962 	sc = disk->d_softc;
1963 	sx_assert(&sc->sc_lock, SX_LOCKED);
1964 
1965 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
1966 	    ("Disk %s is not marked for synchronization.",
1967 	    g_mirror_get_diskname(disk)));
1968 	KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
1969 	    ("Device not in RUNNING state (%s, %u).", sc->sc_name,
1970 	    sc->sc_state));
1971 
1972 	sx_xunlock(&sc->sc_lock);
1973 	g_topology_lock();
1974 	cp = g_new_consumer(sc->sc_sync.ds_geom);
1975 	cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
1976 	error = g_attach(cp, sc->sc_provider);
1977 	KASSERT(error == 0,
1978 	    ("Cannot attach to %s (error=%d).", sc->sc_name, error));
1979 	error = g_access(cp, 1, 0, 0);
1980 	KASSERT(error == 0, ("Cannot open %s (error=%d).", sc->sc_name, error));
1981 	g_topology_unlock();
1982 	sx_xlock(&sc->sc_lock);
1983 
1984 	G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s.", sc->sc_name,
1985 	    g_mirror_get_diskname(disk));
1986 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) == 0)
1987 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1988 	KASSERT(disk->d_sync.ds_consumer == NULL,
1989 	    ("Sync consumer already exists (device=%s, disk=%s).",
1990 	    sc->sc_name, g_mirror_get_diskname(disk)));
1991 
1992 	disk->d_sync.ds_consumer = cp;
1993 	disk->d_sync.ds_consumer->private = disk;
1994 	disk->d_sync.ds_consumer->index = 0;
1995 
1996 	/*
1997 	 * Allocate memory for synchronization bios and initialize them.
1998 	 */
1999 	disk->d_sync.ds_bios = malloc(sizeof(struct bio *) * g_mirror_syncreqs,
2000 	    M_MIRROR, M_WAITOK);
2001 	for (i = 0; i < g_mirror_syncreqs; i++) {
2002 		bp = g_alloc_bio();
2003 		disk->d_sync.ds_bios[i] = bp;
2004 		bp->bio_parent = NULL;
2005 		bp->bio_cmd = BIO_READ;
2006 		bp->bio_data = malloc(MAXPHYS, M_MIRROR, M_WAITOK);
2007 		bp->bio_cflags = 0;
2008 		bp->bio_offset = disk->d_sync.ds_offset;
2009 		bp->bio_length = MIN(MAXPHYS, sc->sc_mediasize - bp->bio_offset);
2010 		disk->d_sync.ds_offset += bp->bio_length;
2011 		bp->bio_done = g_mirror_sync_done;
2012 		bp->bio_from = disk->d_sync.ds_consumer;
2013 		bp->bio_to = sc->sc_provider;
2014 		bp->bio_caller1 = (void *)(uintptr_t)i;
2015 	}
2016 
2017 	/* Increase the number of disks in SYNCHRONIZING state. */
2018 	sc->sc_sync.ds_ndisks++;
2019 	/* Set the number of in-flight synchronization requests. */
2020 	disk->d_sync.ds_inflight = g_mirror_syncreqs;
2021 
2022 	/*
2023 	 * Fire off first synchronization requests.
2024 	 */
2025 	for (i = 0; i < g_mirror_syncreqs; i++) {
2026 		bp = disk->d_sync.ds_bios[i];
2027 		G_MIRROR_LOGREQ(3, bp, "Sending synchronization request.");
2028 		disk->d_sync.ds_consumer->index++;
2029 		/*
2030 		 * Delay the request if it is colliding with a regular request.
2031 		 */
2032 		if (g_mirror_regular_collision(sc, bp))
2033 			g_mirror_sync_delay(sc, bp);
2034 		else
2035 			g_io_request(bp, disk->d_sync.ds_consumer);
2036 	}
2037 }
2038 
2039 /*
2040  * Stop synchronization process.
2041  * type: 0 - synchronization finished
2042  *       1 - synchronization stopped
2043  */
2044 static void
2045 g_mirror_sync_stop(struct g_mirror_disk *disk, int type)
2046 {
2047 	struct g_mirror_softc *sc;
2048 	struct g_consumer *cp;
2049 
2050 	g_topology_assert_not();
2051 	sc = disk->d_softc;
2052 	sx_assert(&sc->sc_lock, SX_LOCKED);
2053 
2054 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2055 	    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2056 	    g_mirror_disk_state2str(disk->d_state)));
2057 	if (disk->d_sync.ds_consumer == NULL)
2058 		return;
2059 
2060 	if (type == 0) {
2061 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s finished.",
2062 		    sc->sc_name, g_mirror_get_diskname(disk));
2063 	} else /* if (type == 1) */ {
2064 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s stopped.",
2065 		    sc->sc_name, g_mirror_get_diskname(disk));
2066 	}
2067 	free(disk->d_sync.ds_bios, M_MIRROR);
2068 	disk->d_sync.ds_bios = NULL;
2069 	cp = disk->d_sync.ds_consumer;
2070 	disk->d_sync.ds_consumer = NULL;
2071 	disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2072 	sc->sc_sync.ds_ndisks--;
2073 	sx_xunlock(&sc->sc_lock); /* Avoid recursion on sc_lock. */
2074 	g_topology_lock();
2075 	g_mirror_kill_consumer(sc, cp);
2076 	g_topology_unlock();
2077 	sx_xlock(&sc->sc_lock);
2078 }
2079 
2080 static void
2081 g_mirror_launch_provider(struct g_mirror_softc *sc)
2082 {
2083 	struct g_mirror_disk *disk;
2084 	struct g_provider *pp, *dp;
2085 
2086 	sx_assert(&sc->sc_lock, SX_LOCKED);
2087 
2088 	g_topology_lock();
2089 	pp = g_new_providerf(sc->sc_geom, "mirror/%s", sc->sc_name);
2090 	pp->flags |= G_PF_DIRECT_RECEIVE;
2091 	pp->mediasize = sc->sc_mediasize;
2092 	pp->sectorsize = sc->sc_sectorsize;
2093 	pp->stripesize = 0;
2094 	pp->stripeoffset = 0;
2095 
2096 	/* Splitting of unmapped BIO's could work but isn't implemented now */
2097 	if (sc->sc_balance != G_MIRROR_BALANCE_SPLIT)
2098 		pp->flags |= G_PF_ACCEPT_UNMAPPED;
2099 
2100 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2101 		if (disk->d_consumer && disk->d_consumer->provider) {
2102 			dp = disk->d_consumer->provider;
2103 			if (dp->stripesize > pp->stripesize) {
2104 				pp->stripesize = dp->stripesize;
2105 				pp->stripeoffset = dp->stripeoffset;
2106 			}
2107 			/* A provider underneath us doesn't support unmapped */
2108 			if ((dp->flags & G_PF_ACCEPT_UNMAPPED) == 0) {
2109 				G_MIRROR_DEBUG(0, "Cancelling unmapped "
2110 				    "because of %s.", dp->name);
2111 				pp->flags &= ~G_PF_ACCEPT_UNMAPPED;
2112 			}
2113 		}
2114 	}
2115 	sc->sc_provider = pp;
2116 	g_error_provider(pp, 0);
2117 	g_topology_unlock();
2118 	G_MIRROR_DEBUG(0, "Device %s launched (%u/%u).", pp->name,
2119 	    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE), sc->sc_ndisks);
2120 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2121 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
2122 			g_mirror_sync_start(disk);
2123 	}
2124 }
2125 
2126 static void
2127 g_mirror_destroy_provider(struct g_mirror_softc *sc)
2128 {
2129 	struct g_mirror_disk *disk;
2130 	struct bio *bp;
2131 
2132 	g_topology_assert_not();
2133 	KASSERT(sc->sc_provider != NULL, ("NULL provider (device=%s).",
2134 	    sc->sc_name));
2135 
2136 	g_topology_lock();
2137 	g_error_provider(sc->sc_provider, ENXIO);
2138 	mtx_lock(&sc->sc_queue_mtx);
2139 	while ((bp = bioq_takefirst(&sc->sc_queue)) != NULL) {
2140 		/*
2141 		 * Abort any pending I/O that wasn't generated by us.
2142 		 * Synchronization requests and requests destined for individual
2143 		 * mirror components can be destroyed immediately.
2144 		 */
2145 		if (bp->bio_to == sc->sc_provider &&
2146 		    bp->bio_from->geom != sc->sc_sync.ds_geom) {
2147 			g_io_deliver(bp, ENXIO);
2148 		} else {
2149 			if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0)
2150 				free(bp->bio_data, M_MIRROR);
2151 			g_destroy_bio(bp);
2152 		}
2153 	}
2154 	mtx_unlock(&sc->sc_queue_mtx);
2155 	G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.", sc->sc_name,
2156 	    sc->sc_provider->name);
2157 	sc->sc_provider->flags |= G_PF_WITHER;
2158 	g_orphan_provider(sc->sc_provider, ENXIO);
2159 	g_topology_unlock();
2160 	sc->sc_provider = NULL;
2161 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2162 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
2163 			g_mirror_sync_stop(disk, 1);
2164 	}
2165 }
2166 
2167 static void
2168 g_mirror_go(void *arg)
2169 {
2170 	struct g_mirror_softc *sc;
2171 
2172 	sc = arg;
2173 	G_MIRROR_DEBUG(0, "Force device %s start due to timeout.", sc->sc_name);
2174 	g_mirror_event_send(sc, 0,
2175 	    G_MIRROR_EVENT_DONTWAIT | G_MIRROR_EVENT_DEVICE);
2176 }
2177 
2178 static u_int
2179 g_mirror_determine_state(struct g_mirror_disk *disk)
2180 {
2181 	struct g_mirror_softc *sc;
2182 	u_int state;
2183 
2184 	sc = disk->d_softc;
2185 	if (sc->sc_syncid == disk->d_sync.ds_syncid) {
2186 		if ((disk->d_flags &
2187 		    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
2188 			/* Disk does not need synchronization. */
2189 			state = G_MIRROR_DISK_STATE_ACTIVE;
2190 		} else {
2191 			if ((sc->sc_flags &
2192 			     G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
2193 			    (disk->d_flags &
2194 			     G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
2195 				/*
2196 				 * We can start synchronization from
2197 				 * the stored offset.
2198 				 */
2199 				state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
2200 			} else {
2201 				state = G_MIRROR_DISK_STATE_STALE;
2202 			}
2203 		}
2204 	} else if (disk->d_sync.ds_syncid < sc->sc_syncid) {
2205 		/*
2206 		 * Reset all synchronization data for this disk,
2207 		 * because if it even was synchronized, it was
2208 		 * synchronized to disks with different syncid.
2209 		 */
2210 		disk->d_flags |= G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2211 		disk->d_sync.ds_offset = 0;
2212 		disk->d_sync.ds_offset_done = 0;
2213 		disk->d_sync.ds_syncid = sc->sc_syncid;
2214 		if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
2215 		    (disk->d_flags & G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
2216 			state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
2217 		} else {
2218 			state = G_MIRROR_DISK_STATE_STALE;
2219 		}
2220 	} else /* if (sc->sc_syncid < disk->d_sync.ds_syncid) */ {
2221 		/*
2222 		 * Not good, NOT GOOD!
2223 		 * It means that mirror was started on stale disks
2224 		 * and more fresh disk just arrive.
2225 		 * If there were writes, mirror is broken, sorry.
2226 		 * I think the best choice here is don't touch
2227 		 * this disk and inform the user loudly.
2228 		 */
2229 		G_MIRROR_DEBUG(0, "Device %s was started before the freshest "
2230 		    "disk (%s) arrives!! It will not be connected to the "
2231 		    "running device.", sc->sc_name,
2232 		    g_mirror_get_diskname(disk));
2233 		g_mirror_destroy_disk(disk);
2234 		state = G_MIRROR_DISK_STATE_NONE;
2235 		/* Return immediately, because disk was destroyed. */
2236 		return (state);
2237 	}
2238 	G_MIRROR_DEBUG(3, "State for %s disk: %s.",
2239 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(state));
2240 	return (state);
2241 }
2242 
2243 /*
2244  * Update device state.
2245  */
2246 static void
2247 g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force)
2248 {
2249 	struct g_mirror_disk *disk;
2250 	u_int state;
2251 
2252 	sx_assert(&sc->sc_lock, SX_XLOCKED);
2253 
2254 	switch (sc->sc_state) {
2255 	case G_MIRROR_DEVICE_STATE_STARTING:
2256 	    {
2257 		struct g_mirror_disk *pdisk, *tdisk;
2258 		u_int dirty, ndisks, genid, syncid;
2259 
2260 		KASSERT(sc->sc_provider == NULL,
2261 		    ("Non-NULL provider in STARTING state (%s).", sc->sc_name));
2262 		/*
2263 		 * Are we ready? We are, if all disks are connected or
2264 		 * if we have any disks and 'force' is true.
2265 		 */
2266 		ndisks = g_mirror_ndisks(sc, -1);
2267 		if (sc->sc_ndisks == ndisks || (force && ndisks > 0)) {
2268 			;
2269 		} else if (ndisks == 0) {
2270 			/*
2271 			 * Disks went down in starting phase, so destroy
2272 			 * device.
2273 			 */
2274 			callout_drain(&sc->sc_callout);
2275 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2276 			G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p", __LINE__,
2277 			    sc->sc_rootmount);
2278 			root_mount_rel(sc->sc_rootmount);
2279 			sc->sc_rootmount = NULL;
2280 			return;
2281 		} else {
2282 			return;
2283 		}
2284 
2285 		/*
2286 		 * Activate all disks with the biggest syncid.
2287 		 */
2288 		if (force) {
2289 			/*
2290 			 * If 'force' is true, we have been called due to
2291 			 * timeout, so don't bother canceling timeout.
2292 			 */
2293 			ndisks = 0;
2294 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2295 				if ((disk->d_flags &
2296 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
2297 					ndisks++;
2298 				}
2299 			}
2300 			if (ndisks == 0) {
2301 				/* No valid disks found, destroy device. */
2302 				sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2303 				G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p",
2304 				    __LINE__, sc->sc_rootmount);
2305 				root_mount_rel(sc->sc_rootmount);
2306 				sc->sc_rootmount = NULL;
2307 				return;
2308 			}
2309 		} else {
2310 			/* Cancel timeout. */
2311 			callout_drain(&sc->sc_callout);
2312 		}
2313 
2314 		/*
2315 		 * Find the biggest genid.
2316 		 */
2317 		genid = 0;
2318 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2319 			if (disk->d_genid > genid)
2320 				genid = disk->d_genid;
2321 		}
2322 		sc->sc_genid = genid;
2323 		/*
2324 		 * Remove all disks without the biggest genid.
2325 		 */
2326 		LIST_FOREACH_SAFE(disk, &sc->sc_disks, d_next, tdisk) {
2327 			if (disk->d_genid < genid) {
2328 				G_MIRROR_DEBUG(0,
2329 				    "Component %s (device %s) broken, skipping.",
2330 				    g_mirror_get_diskname(disk), sc->sc_name);
2331 				g_mirror_destroy_disk(disk);
2332 			}
2333 		}
2334 
2335 		/*
2336 		 * Find the biggest syncid.
2337 		 */
2338 		syncid = 0;
2339 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2340 			if (disk->d_sync.ds_syncid > syncid)
2341 				syncid = disk->d_sync.ds_syncid;
2342 		}
2343 
2344 		/*
2345 		 * Here we need to look for dirty disks and if all disks
2346 		 * with the biggest syncid are dirty, we have to choose
2347 		 * one with the biggest priority and rebuild the rest.
2348 		 */
2349 		/*
2350 		 * Find the number of dirty disks with the biggest syncid.
2351 		 * Find the number of disks with the biggest syncid.
2352 		 * While here, find a disk with the biggest priority.
2353 		 */
2354 		dirty = ndisks = 0;
2355 		pdisk = NULL;
2356 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2357 			if (disk->d_sync.ds_syncid != syncid)
2358 				continue;
2359 			if ((disk->d_flags &
2360 			    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2361 				continue;
2362 			}
2363 			ndisks++;
2364 			if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
2365 				dirty++;
2366 				if (pdisk == NULL ||
2367 				    pdisk->d_priority < disk->d_priority) {
2368 					pdisk = disk;
2369 				}
2370 			}
2371 		}
2372 		if (dirty == 0) {
2373 			/* No dirty disks at all, great. */
2374 		} else if (dirty == ndisks) {
2375 			/*
2376 			 * Force synchronization for all dirty disks except one
2377 			 * with the biggest priority.
2378 			 */
2379 			KASSERT(pdisk != NULL, ("pdisk == NULL"));
2380 			G_MIRROR_DEBUG(1, "Using disk %s (device %s) as a "
2381 			    "master disk for synchronization.",
2382 			    g_mirror_get_diskname(pdisk), sc->sc_name);
2383 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2384 				if (disk->d_sync.ds_syncid != syncid)
2385 					continue;
2386 				if ((disk->d_flags &
2387 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2388 					continue;
2389 				}
2390 				KASSERT((disk->d_flags &
2391 				    G_MIRROR_DISK_FLAG_DIRTY) != 0,
2392 				    ("Disk %s isn't marked as dirty.",
2393 				    g_mirror_get_diskname(disk)));
2394 				/* Skip the disk with the biggest priority. */
2395 				if (disk == pdisk)
2396 					continue;
2397 				disk->d_sync.ds_syncid = 0;
2398 			}
2399 		} else if (dirty < ndisks) {
2400 			/*
2401 			 * Force synchronization for all dirty disks.
2402 			 * We have some non-dirty disks.
2403 			 */
2404 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2405 				if (disk->d_sync.ds_syncid != syncid)
2406 					continue;
2407 				if ((disk->d_flags &
2408 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2409 					continue;
2410 				}
2411 				if ((disk->d_flags &
2412 				    G_MIRROR_DISK_FLAG_DIRTY) == 0) {
2413 					continue;
2414 				}
2415 				disk->d_sync.ds_syncid = 0;
2416 			}
2417 		}
2418 
2419 		/* Reset hint. */
2420 		sc->sc_hint = NULL;
2421 		sc->sc_syncid = syncid;
2422 		if (force) {
2423 			/* Remember to bump syncid on first write. */
2424 			sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2425 		}
2426 		state = G_MIRROR_DEVICE_STATE_RUNNING;
2427 		G_MIRROR_DEBUG(1, "Device %s state changed from %s to %s.",
2428 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state),
2429 		    g_mirror_device_state2str(state));
2430 		sc->sc_state = state;
2431 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2432 			state = g_mirror_determine_state(disk);
2433 			g_mirror_event_send(disk, state,
2434 			    G_MIRROR_EVENT_DONTWAIT);
2435 			if (state == G_MIRROR_DISK_STATE_STALE)
2436 				sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2437 		}
2438 		break;
2439 	    }
2440 	case G_MIRROR_DEVICE_STATE_RUNNING:
2441 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 0 &&
2442 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2443 			/*
2444 			 * No active disks or no disks at all,
2445 			 * so destroy device.
2446 			 */
2447 			if (sc->sc_provider != NULL)
2448 				g_mirror_destroy_provider(sc);
2449 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2450 			break;
2451 		} else if (g_mirror_ndisks(sc,
2452 		    G_MIRROR_DISK_STATE_ACTIVE) > 0 &&
2453 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2454 			/*
2455 			 * We have active disks, launch provider if it doesn't
2456 			 * exist.
2457 			 */
2458 			if (sc->sc_provider == NULL)
2459 				g_mirror_launch_provider(sc);
2460 			if (sc->sc_rootmount != NULL) {
2461 				G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p",
2462 				    __LINE__, sc->sc_rootmount);
2463 				root_mount_rel(sc->sc_rootmount);
2464 				sc->sc_rootmount = NULL;
2465 			}
2466 		}
2467 		/*
2468 		 * Genid should be bumped immediately, so do it here.
2469 		 */
2470 		if ((sc->sc_bump_id & G_MIRROR_BUMP_GENID) != 0) {
2471 			sc->sc_bump_id &= ~G_MIRROR_BUMP_GENID;
2472 			g_mirror_bump_genid(sc);
2473 		}
2474 		break;
2475 	default:
2476 		KASSERT(1 == 0, ("Wrong device state (%s, %s).",
2477 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state)));
2478 		break;
2479 	}
2480 }
2481 
2482 /*
2483  * Update disk state and device state if needed.
2484  */
2485 #define	DISK_STATE_CHANGED()	G_MIRROR_DEBUG(1,			\
2486 	"Disk %s state changed from %s to %s (device %s).",		\
2487 	g_mirror_get_diskname(disk),					\
2488 	g_mirror_disk_state2str(disk->d_state),				\
2489 	g_mirror_disk_state2str(state), sc->sc_name)
2490 static int
2491 g_mirror_update_disk(struct g_mirror_disk *disk, u_int state)
2492 {
2493 	struct g_mirror_softc *sc;
2494 
2495 	sc = disk->d_softc;
2496 	sx_assert(&sc->sc_lock, SX_XLOCKED);
2497 
2498 again:
2499 	G_MIRROR_DEBUG(3, "Changing disk %s state from %s to %s.",
2500 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(disk->d_state),
2501 	    g_mirror_disk_state2str(state));
2502 	switch (state) {
2503 	case G_MIRROR_DISK_STATE_NEW:
2504 		/*
2505 		 * Possible scenarios:
2506 		 * 1. New disk arrive.
2507 		 */
2508 		/* Previous state should be NONE. */
2509 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NONE,
2510 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2511 		    g_mirror_disk_state2str(disk->d_state)));
2512 		DISK_STATE_CHANGED();
2513 
2514 		disk->d_state = state;
2515 		if (LIST_EMPTY(&sc->sc_disks))
2516 			LIST_INSERT_HEAD(&sc->sc_disks, disk, d_next);
2517 		else {
2518 			struct g_mirror_disk *dp;
2519 
2520 			LIST_FOREACH(dp, &sc->sc_disks, d_next) {
2521 				if (disk->d_priority >= dp->d_priority) {
2522 					LIST_INSERT_BEFORE(dp, disk, d_next);
2523 					dp = NULL;
2524 					break;
2525 				}
2526 				if (LIST_NEXT(dp, d_next) == NULL)
2527 					break;
2528 			}
2529 			if (dp != NULL)
2530 				LIST_INSERT_AFTER(dp, disk, d_next);
2531 		}
2532 		G_MIRROR_DEBUG(1, "Device %s: provider %s detected.",
2533 		    sc->sc_name, g_mirror_get_diskname(disk));
2534 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
2535 			break;
2536 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2537 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2538 		    g_mirror_device_state2str(sc->sc_state),
2539 		    g_mirror_get_diskname(disk),
2540 		    g_mirror_disk_state2str(disk->d_state)));
2541 		state = g_mirror_determine_state(disk);
2542 		if (state != G_MIRROR_DISK_STATE_NONE)
2543 			goto again;
2544 		break;
2545 	case G_MIRROR_DISK_STATE_ACTIVE:
2546 		/*
2547 		 * Possible scenarios:
2548 		 * 1. New disk does not need synchronization.
2549 		 * 2. Synchronization process finished successfully.
2550 		 */
2551 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2552 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2553 		    g_mirror_device_state2str(sc->sc_state),
2554 		    g_mirror_get_diskname(disk),
2555 		    g_mirror_disk_state2str(disk->d_state)));
2556 		/* Previous state should be NEW or SYNCHRONIZING. */
2557 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW ||
2558 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2559 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2560 		    g_mirror_disk_state2str(disk->d_state)));
2561 		DISK_STATE_CHANGED();
2562 
2563 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2564 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2565 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_FORCE_SYNC;
2566 			g_mirror_sync_stop(disk, 0);
2567 		}
2568 		disk->d_state = state;
2569 		disk->d_sync.ds_offset = 0;
2570 		disk->d_sync.ds_offset_done = 0;
2571 		g_mirror_update_idle(sc, disk);
2572 		g_mirror_update_metadata(disk);
2573 		G_MIRROR_DEBUG(1, "Device %s: provider %s activated.",
2574 		    sc->sc_name, g_mirror_get_diskname(disk));
2575 		break;
2576 	case G_MIRROR_DISK_STATE_STALE:
2577 		/*
2578 		 * Possible scenarios:
2579 		 * 1. Stale disk was connected.
2580 		 */
2581 		/* Previous state should be NEW. */
2582 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2583 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2584 		    g_mirror_disk_state2str(disk->d_state)));
2585 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2586 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2587 		    g_mirror_device_state2str(sc->sc_state),
2588 		    g_mirror_get_diskname(disk),
2589 		    g_mirror_disk_state2str(disk->d_state)));
2590 		/*
2591 		 * STALE state is only possible if device is marked
2592 		 * NOAUTOSYNC.
2593 		 */
2594 		KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) != 0,
2595 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2596 		    g_mirror_device_state2str(sc->sc_state),
2597 		    g_mirror_get_diskname(disk),
2598 		    g_mirror_disk_state2str(disk->d_state)));
2599 		DISK_STATE_CHANGED();
2600 
2601 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2602 		disk->d_state = state;
2603 		g_mirror_update_metadata(disk);
2604 		G_MIRROR_DEBUG(0, "Device %s: provider %s is stale.",
2605 		    sc->sc_name, g_mirror_get_diskname(disk));
2606 		break;
2607 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
2608 		/*
2609 		 * Possible scenarios:
2610 		 * 1. Disk which needs synchronization was connected.
2611 		 */
2612 		/* Previous state should be NEW. */
2613 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2614 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2615 		    g_mirror_disk_state2str(disk->d_state)));
2616 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2617 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2618 		    g_mirror_device_state2str(sc->sc_state),
2619 		    g_mirror_get_diskname(disk),
2620 		    g_mirror_disk_state2str(disk->d_state)));
2621 		DISK_STATE_CHANGED();
2622 
2623 		if (disk->d_state == G_MIRROR_DISK_STATE_NEW)
2624 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2625 		disk->d_state = state;
2626 		if (sc->sc_provider != NULL) {
2627 			g_mirror_sync_start(disk);
2628 			g_mirror_update_metadata(disk);
2629 		}
2630 		break;
2631 	case G_MIRROR_DISK_STATE_DISCONNECTED:
2632 		/*
2633 		 * Possible scenarios:
2634 		 * 1. Device wasn't running yet, but disk disappear.
2635 		 * 2. Disk was active and disapppear.
2636 		 * 3. Disk disappear during synchronization process.
2637 		 */
2638 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING) {
2639 			/*
2640 			 * Previous state should be ACTIVE, STALE or
2641 			 * SYNCHRONIZING.
2642 			 */
2643 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
2644 			    disk->d_state == G_MIRROR_DISK_STATE_STALE ||
2645 			    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2646 			    ("Wrong disk state (%s, %s).",
2647 			    g_mirror_get_diskname(disk),
2648 			    g_mirror_disk_state2str(disk->d_state)));
2649 		} else if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING) {
2650 			/* Previous state should be NEW. */
2651 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2652 			    ("Wrong disk state (%s, %s).",
2653 			    g_mirror_get_diskname(disk),
2654 			    g_mirror_disk_state2str(disk->d_state)));
2655 			/*
2656 			 * Reset bumping syncid if disk disappeared in STARTING
2657 			 * state.
2658 			 */
2659 			if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0)
2660 				sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
2661 #ifdef	INVARIANTS
2662 		} else {
2663 			KASSERT(1 == 0, ("Wrong device state (%s, %s, %s, %s).",
2664 			    sc->sc_name,
2665 			    g_mirror_device_state2str(sc->sc_state),
2666 			    g_mirror_get_diskname(disk),
2667 			    g_mirror_disk_state2str(disk->d_state)));
2668 #endif
2669 		}
2670 		DISK_STATE_CHANGED();
2671 		G_MIRROR_DEBUG(0, "Device %s: provider %s disconnected.",
2672 		    sc->sc_name, g_mirror_get_diskname(disk));
2673 
2674 		g_mirror_destroy_disk(disk);
2675 		break;
2676 	case G_MIRROR_DISK_STATE_DESTROY:
2677 	    {
2678 		int error;
2679 
2680 		error = g_mirror_clear_metadata(disk);
2681 		if (error != 0) {
2682 			G_MIRROR_DEBUG(0,
2683 			    "Device %s: failed to clear metadata on %s: %d.",
2684 			    sc->sc_name, g_mirror_get_diskname(disk), error);
2685 			break;
2686 		}
2687 		DISK_STATE_CHANGED();
2688 		G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.",
2689 		    sc->sc_name, g_mirror_get_diskname(disk));
2690 
2691 		g_mirror_destroy_disk(disk);
2692 		sc->sc_ndisks--;
2693 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2694 			g_mirror_update_metadata(disk);
2695 		}
2696 		break;
2697 	    }
2698 	default:
2699 		KASSERT(1 == 0, ("Unknown state (%u).", state));
2700 		break;
2701 	}
2702 	return (0);
2703 }
2704 #undef	DISK_STATE_CHANGED
2705 
2706 int
2707 g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md)
2708 {
2709 	struct g_provider *pp;
2710 	u_char *buf;
2711 	int error;
2712 
2713 	g_topology_assert();
2714 
2715 	error = g_access(cp, 1, 0, 0);
2716 	if (error != 0)
2717 		return (error);
2718 	pp = cp->provider;
2719 	g_topology_unlock();
2720 	/* Metadata are stored on last sector. */
2721 	buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
2722 	    &error);
2723 	g_topology_lock();
2724 	g_access(cp, -1, 0, 0);
2725 	if (buf == NULL) {
2726 		G_MIRROR_DEBUG(1, "Cannot read metadata from %s (error=%d).",
2727 		    cp->provider->name, error);
2728 		return (error);
2729 	}
2730 
2731 	/* Decode metadata. */
2732 	error = mirror_metadata_decode(buf, md);
2733 	g_free(buf);
2734 	if (strcmp(md->md_magic, G_MIRROR_MAGIC) != 0)
2735 		return (EINVAL);
2736 	if (md->md_version > G_MIRROR_VERSION) {
2737 		G_MIRROR_DEBUG(0,
2738 		    "Kernel module is too old to handle metadata from %s.",
2739 		    cp->provider->name);
2740 		return (EINVAL);
2741 	}
2742 	if (error != 0) {
2743 		G_MIRROR_DEBUG(1, "MD5 metadata hash mismatch for provider %s.",
2744 		    cp->provider->name);
2745 		return (error);
2746 	}
2747 
2748 	return (0);
2749 }
2750 
2751 static int
2752 g_mirror_check_metadata(struct g_mirror_softc *sc, struct g_provider *pp,
2753     struct g_mirror_metadata *md)
2754 {
2755 
2756 	if (g_mirror_id2disk(sc, md->md_did) != NULL) {
2757 		G_MIRROR_DEBUG(1, "Disk %s (id=%u) already exists, skipping.",
2758 		    pp->name, md->md_did);
2759 		return (EEXIST);
2760 	}
2761 	if (md->md_all != sc->sc_ndisks) {
2762 		G_MIRROR_DEBUG(1,
2763 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2764 		    "md_all", pp->name, sc->sc_name);
2765 		return (EINVAL);
2766 	}
2767 	if (md->md_slice != sc->sc_slice) {
2768 		G_MIRROR_DEBUG(1,
2769 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2770 		    "md_slice", pp->name, sc->sc_name);
2771 		return (EINVAL);
2772 	}
2773 	if (md->md_balance != sc->sc_balance) {
2774 		G_MIRROR_DEBUG(1,
2775 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2776 		    "md_balance", pp->name, sc->sc_name);
2777 		return (EINVAL);
2778 	}
2779 #if 0
2780 	if (md->md_mediasize != sc->sc_mediasize) {
2781 		G_MIRROR_DEBUG(1,
2782 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2783 		    "md_mediasize", pp->name, sc->sc_name);
2784 		return (EINVAL);
2785 	}
2786 #endif
2787 	if (sc->sc_mediasize > pp->mediasize) {
2788 		G_MIRROR_DEBUG(1,
2789 		    "Invalid size of disk %s (device %s), skipping.", pp->name,
2790 		    sc->sc_name);
2791 		return (EINVAL);
2792 	}
2793 	if (md->md_sectorsize != sc->sc_sectorsize) {
2794 		G_MIRROR_DEBUG(1,
2795 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2796 		    "md_sectorsize", pp->name, sc->sc_name);
2797 		return (EINVAL);
2798 	}
2799 	if ((sc->sc_sectorsize % pp->sectorsize) != 0) {
2800 		G_MIRROR_DEBUG(1,
2801 		    "Invalid sector size of disk %s (device %s), skipping.",
2802 		    pp->name, sc->sc_name);
2803 		return (EINVAL);
2804 	}
2805 	if ((md->md_mflags & ~G_MIRROR_DEVICE_FLAG_MASK) != 0) {
2806 		G_MIRROR_DEBUG(1,
2807 		    "Invalid device flags on disk %s (device %s), skipping.",
2808 		    pp->name, sc->sc_name);
2809 		return (EINVAL);
2810 	}
2811 	if ((md->md_dflags & ~G_MIRROR_DISK_FLAG_MASK) != 0) {
2812 		G_MIRROR_DEBUG(1,
2813 		    "Invalid disk flags on disk %s (device %s), skipping.",
2814 		    pp->name, sc->sc_name);
2815 		return (EINVAL);
2816 	}
2817 	return (0);
2818 }
2819 
2820 int
2821 g_mirror_add_disk(struct g_mirror_softc *sc, struct g_provider *pp,
2822     struct g_mirror_metadata *md)
2823 {
2824 	struct g_mirror_disk *disk;
2825 	int error;
2826 
2827 	g_topology_assert_not();
2828 	G_MIRROR_DEBUG(2, "Adding disk %s.", pp->name);
2829 
2830 	error = g_mirror_check_metadata(sc, pp, md);
2831 	if (error != 0)
2832 		return (error);
2833 	if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING &&
2834 	    md->md_genid < sc->sc_genid) {
2835 		G_MIRROR_DEBUG(0, "Component %s (device %s) broken, skipping.",
2836 		    pp->name, sc->sc_name);
2837 		return (EINVAL);
2838 	}
2839 	disk = g_mirror_init_disk(sc, pp, md, &error);
2840 	if (disk == NULL)
2841 		return (error);
2842 	error = g_mirror_event_send(disk, G_MIRROR_DISK_STATE_NEW,
2843 	    G_MIRROR_EVENT_WAIT);
2844 	if (error != 0)
2845 		return (error);
2846 	if (md->md_version < G_MIRROR_VERSION) {
2847 		G_MIRROR_DEBUG(0, "Upgrading metadata on %s (v%d->v%d).",
2848 		    pp->name, md->md_version, G_MIRROR_VERSION);
2849 		g_mirror_update_metadata(disk);
2850 	}
2851 	return (0);
2852 }
2853 
2854 static void
2855 g_mirror_destroy_delayed(void *arg, int flag)
2856 {
2857 	struct g_mirror_softc *sc;
2858 	int error;
2859 
2860 	if (flag == EV_CANCEL) {
2861 		G_MIRROR_DEBUG(1, "Destroying canceled.");
2862 		return;
2863 	}
2864 	sc = arg;
2865 	g_topology_unlock();
2866 	sx_xlock(&sc->sc_lock);
2867 	KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) == 0,
2868 	    ("DESTROY flag set on %s.", sc->sc_name));
2869 	KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROYING) != 0,
2870 	    ("DESTROYING flag not set on %s.", sc->sc_name));
2871 	G_MIRROR_DEBUG(1, "Destroying %s (delayed).", sc->sc_name);
2872 	error = g_mirror_destroy(sc, G_MIRROR_DESTROY_SOFT);
2873 	if (error != 0) {
2874 		G_MIRROR_DEBUG(0, "Cannot destroy %s (error=%d).",
2875 		    sc->sc_name, error);
2876 		sx_xunlock(&sc->sc_lock);
2877 	}
2878 	g_topology_lock();
2879 }
2880 
2881 static int
2882 g_mirror_access(struct g_provider *pp, int acr, int acw, int ace)
2883 {
2884 	struct g_mirror_softc *sc;
2885 	int dcr, dcw, dce, error = 0;
2886 
2887 	g_topology_assert();
2888 	G_MIRROR_DEBUG(2, "Access request for %s: r%dw%de%d.", pp->name, acr,
2889 	    acw, ace);
2890 
2891 	sc = pp->geom->softc;
2892 	if (sc == NULL && acr <= 0 && acw <= 0 && ace <= 0)
2893 		return (0);
2894 	KASSERT(sc != NULL, ("NULL softc (provider=%s).", pp->name));
2895 
2896 	dcr = pp->acr + acr;
2897 	dcw = pp->acw + acw;
2898 	dce = pp->ace + ace;
2899 
2900 	g_topology_unlock();
2901 	sx_xlock(&sc->sc_lock);
2902 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0 ||
2903 	    LIST_EMPTY(&sc->sc_disks)) {
2904 		if (acr > 0 || acw > 0 || ace > 0)
2905 			error = ENXIO;
2906 		goto end;
2907 	}
2908 	if (dcw == 0)
2909 		g_mirror_idle(sc, dcw);
2910 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROYING) != 0) {
2911 		if (acr > 0 || acw > 0 || ace > 0) {
2912 			error = ENXIO;
2913 			goto end;
2914 		}
2915 		if (dcr == 0 && dcw == 0 && dce == 0) {
2916 			g_post_event(g_mirror_destroy_delayed, sc, M_WAITOK,
2917 			    sc, NULL);
2918 		}
2919 	}
2920 end:
2921 	sx_xunlock(&sc->sc_lock);
2922 	g_topology_lock();
2923 	return (error);
2924 }
2925 
2926 static struct g_geom *
2927 g_mirror_create(struct g_class *mp, const struct g_mirror_metadata *md)
2928 {
2929 	struct g_mirror_softc *sc;
2930 	struct g_geom *gp;
2931 	int error, timeout;
2932 
2933 	g_topology_assert();
2934 	G_MIRROR_DEBUG(1, "Creating device %s (id=%u).", md->md_name,
2935 	    md->md_mid);
2936 
2937 	/* One disk is minimum. */
2938 	if (md->md_all < 1)
2939 		return (NULL);
2940 	/*
2941 	 * Action geom.
2942 	 */
2943 	gp = g_new_geomf(mp, "%s", md->md_name);
2944 	sc = malloc(sizeof(*sc), M_MIRROR, M_WAITOK | M_ZERO);
2945 	gp->start = g_mirror_start;
2946 	gp->orphan = g_mirror_orphan;
2947 	gp->access = g_mirror_access;
2948 	gp->dumpconf = g_mirror_dumpconf;
2949 
2950 	sc->sc_id = md->md_mid;
2951 	sc->sc_slice = md->md_slice;
2952 	sc->sc_balance = md->md_balance;
2953 	sc->sc_mediasize = md->md_mediasize;
2954 	sc->sc_sectorsize = md->md_sectorsize;
2955 	sc->sc_ndisks = md->md_all;
2956 	sc->sc_flags = md->md_mflags;
2957 	sc->sc_bump_id = 0;
2958 	sc->sc_idle = 1;
2959 	sc->sc_last_write = time_uptime;
2960 	sc->sc_writes = 0;
2961 	sx_init(&sc->sc_lock, "gmirror:lock");
2962 	bioq_init(&sc->sc_queue);
2963 	mtx_init(&sc->sc_queue_mtx, "gmirror:queue", NULL, MTX_DEF);
2964 	bioq_init(&sc->sc_regular_delayed);
2965 	bioq_init(&sc->sc_inflight);
2966 	bioq_init(&sc->sc_sync_delayed);
2967 	LIST_INIT(&sc->sc_disks);
2968 	TAILQ_INIT(&sc->sc_events);
2969 	mtx_init(&sc->sc_events_mtx, "gmirror:events", NULL, MTX_DEF);
2970 	callout_init(&sc->sc_callout, 1);
2971 	mtx_init(&sc->sc_done_mtx, "gmirror:done", NULL, MTX_DEF);
2972 	sc->sc_state = G_MIRROR_DEVICE_STATE_STARTING;
2973 	gp->softc = sc;
2974 	sc->sc_geom = gp;
2975 	sc->sc_provider = NULL;
2976 	/*
2977 	 * Synchronization geom.
2978 	 */
2979 	gp = g_new_geomf(mp, "%s.sync", md->md_name);
2980 	gp->softc = sc;
2981 	gp->orphan = g_mirror_orphan;
2982 	sc->sc_sync.ds_geom = gp;
2983 	sc->sc_sync.ds_ndisks = 0;
2984 	error = kproc_create(g_mirror_worker, sc, &sc->sc_worker, 0, 0,
2985 	    "g_mirror %s", md->md_name);
2986 	if (error != 0) {
2987 		G_MIRROR_DEBUG(1, "Cannot create kernel thread for %s.",
2988 		    sc->sc_name);
2989 		g_destroy_geom(sc->sc_sync.ds_geom);
2990 		mtx_destroy(&sc->sc_done_mtx);
2991 		mtx_destroy(&sc->sc_events_mtx);
2992 		mtx_destroy(&sc->sc_queue_mtx);
2993 		sx_destroy(&sc->sc_lock);
2994 		g_destroy_geom(sc->sc_geom);
2995 		free(sc, M_MIRROR);
2996 		return (NULL);
2997 	}
2998 
2999 	G_MIRROR_DEBUG(1, "Device %s created (%u components, id=%u).",
3000 	    sc->sc_name, sc->sc_ndisks, sc->sc_id);
3001 
3002 	sc->sc_rootmount = root_mount_hold("GMIRROR");
3003 	G_MIRROR_DEBUG(1, "root_mount_hold %p", sc->sc_rootmount);
3004 	/*
3005 	 * Run timeout.
3006 	 */
3007 	timeout = g_mirror_timeout * hz;
3008 	callout_reset(&sc->sc_callout, timeout, g_mirror_go, sc);
3009 	return (sc->sc_geom);
3010 }
3011 
3012 int
3013 g_mirror_destroy(struct g_mirror_softc *sc, int how)
3014 {
3015 	struct g_mirror_disk *disk;
3016 	struct g_provider *pp;
3017 
3018 	g_topology_assert_not();
3019 	if (sc == NULL)
3020 		return (ENXIO);
3021 	sx_assert(&sc->sc_lock, SX_XLOCKED);
3022 
3023 	pp = sc->sc_provider;
3024 	if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0 ||
3025 	    SCHEDULER_STOPPED())) {
3026 		switch (how) {
3027 		case G_MIRROR_DESTROY_SOFT:
3028 			G_MIRROR_DEBUG(1,
3029 			    "Device %s is still open (r%dw%de%d).", pp->name,
3030 			    pp->acr, pp->acw, pp->ace);
3031 			return (EBUSY);
3032 		case G_MIRROR_DESTROY_DELAYED:
3033 			G_MIRROR_DEBUG(1,
3034 			    "Device %s will be destroyed on last close.",
3035 			    pp->name);
3036 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
3037 				if (disk->d_state ==
3038 				    G_MIRROR_DISK_STATE_SYNCHRONIZING) {
3039 					g_mirror_sync_stop(disk, 1);
3040 				}
3041 			}
3042 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROYING;
3043 			return (EBUSY);
3044 		case G_MIRROR_DESTROY_HARD:
3045 			G_MIRROR_DEBUG(1, "Device %s is still open, so it "
3046 			    "can't be definitely removed.", pp->name);
3047 		}
3048 	}
3049 
3050 	g_topology_lock();
3051 	if (sc->sc_geom->softc == NULL) {
3052 		g_topology_unlock();
3053 		return (0);
3054 	}
3055 	sc->sc_geom->softc = NULL;
3056 	sc->sc_sync.ds_geom->softc = NULL;
3057 	g_topology_unlock();
3058 
3059 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
3060 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_WAIT;
3061 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
3062 	sx_xunlock(&sc->sc_lock);
3063 	mtx_lock(&sc->sc_queue_mtx);
3064 	wakeup(sc);
3065 	mtx_unlock(&sc->sc_queue_mtx);
3066 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, &sc->sc_worker);
3067 	while (sc->sc_worker != NULL)
3068 		tsleep(&sc->sc_worker, PRIBIO, "m:destroy", hz / 5);
3069 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, &sc->sc_worker);
3070 	sx_xlock(&sc->sc_lock);
3071 	g_mirror_destroy_device(sc);
3072 	free(sc, M_MIRROR);
3073 	return (0);
3074 }
3075 
3076 static void
3077 g_mirror_taste_orphan(struct g_consumer *cp)
3078 {
3079 
3080 	KASSERT(1 == 0, ("%s called while tasting %s.", __func__,
3081 	    cp->provider->name));
3082 }
3083 
3084 static struct g_geom *
3085 g_mirror_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
3086 {
3087 	struct g_mirror_metadata md;
3088 	struct g_mirror_softc *sc;
3089 	struct g_consumer *cp;
3090 	struct g_geom *gp;
3091 	int error;
3092 
3093 	g_topology_assert();
3094 	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
3095 	G_MIRROR_DEBUG(2, "Tasting %s.", pp->name);
3096 
3097 	gp = g_new_geomf(mp, "mirror:taste");
3098 	/*
3099 	 * This orphan function should be never called.
3100 	 */
3101 	gp->orphan = g_mirror_taste_orphan;
3102 	cp = g_new_consumer(gp);
3103 	g_attach(cp, pp);
3104 	error = g_mirror_read_metadata(cp, &md);
3105 	g_detach(cp);
3106 	g_destroy_consumer(cp);
3107 	g_destroy_geom(gp);
3108 	if (error != 0)
3109 		return (NULL);
3110 	gp = NULL;
3111 
3112 	if (md.md_provider[0] != '\0' &&
3113 	    !g_compare_names(md.md_provider, pp->name))
3114 		return (NULL);
3115 	if (md.md_provsize != 0 && md.md_provsize != pp->mediasize)
3116 		return (NULL);
3117 	if ((md.md_dflags & G_MIRROR_DISK_FLAG_INACTIVE) != 0) {
3118 		G_MIRROR_DEBUG(0,
3119 		    "Device %s: provider %s marked as inactive, skipping.",
3120 		    md.md_name, pp->name);
3121 		return (NULL);
3122 	}
3123 	if (g_mirror_debug >= 2)
3124 		mirror_metadata_dump(&md);
3125 
3126 	/*
3127 	 * Let's check if device already exists.
3128 	 */
3129 	sc = NULL;
3130 	LIST_FOREACH(gp, &mp->geom, geom) {
3131 		sc = gp->softc;
3132 		if (sc == NULL)
3133 			continue;
3134 		if (sc->sc_sync.ds_geom == gp)
3135 			continue;
3136 		if (strcmp(md.md_name, sc->sc_name) != 0)
3137 			continue;
3138 		if (md.md_mid != sc->sc_id) {
3139 			G_MIRROR_DEBUG(0, "Device %s already configured.",
3140 			    sc->sc_name);
3141 			return (NULL);
3142 		}
3143 		break;
3144 	}
3145 	if (gp == NULL) {
3146 		gp = g_mirror_create(mp, &md);
3147 		if (gp == NULL) {
3148 			G_MIRROR_DEBUG(0, "Cannot create device %s.",
3149 			    md.md_name);
3150 			return (NULL);
3151 		}
3152 		sc = gp->softc;
3153 	}
3154 	G_MIRROR_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
3155 	g_topology_unlock();
3156 	sx_xlock(&sc->sc_lock);
3157 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_TASTING;
3158 	error = g_mirror_add_disk(sc, pp, &md);
3159 	if (error != 0) {
3160 		G_MIRROR_DEBUG(0, "Cannot add disk %s to %s (error=%d).",
3161 		    pp->name, gp->name, error);
3162 		if (LIST_EMPTY(&sc->sc_disks)) {
3163 			g_cancel_event(sc);
3164 			g_mirror_destroy(sc, G_MIRROR_DESTROY_HARD);
3165 			g_topology_lock();
3166 			return (NULL);
3167 		}
3168 		gp = NULL;
3169 	}
3170 	sc->sc_flags &= ~G_MIRROR_DEVICE_FLAG_TASTING;
3171 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
3172 		g_mirror_destroy(sc, G_MIRROR_DESTROY_HARD);
3173 		g_topology_lock();
3174 		return (NULL);
3175 	}
3176 	sx_xunlock(&sc->sc_lock);
3177 	g_topology_lock();
3178 	return (gp);
3179 }
3180 
3181 static void
3182 g_mirror_resize(struct g_consumer *cp)
3183 {
3184 	struct g_mirror_disk *disk;
3185 
3186 	g_topology_assert();
3187 	g_trace(G_T_TOPOLOGY, "%s(%s)", __func__, cp->provider->name);
3188 
3189 	disk = cp->private;
3190 	if (disk == NULL)
3191 		return;
3192 	g_topology_unlock();
3193 	g_mirror_update_metadata(disk);
3194 	g_topology_lock();
3195 }
3196 
3197 static int
3198 g_mirror_destroy_geom(struct gctl_req *req __unused,
3199     struct g_class *mp __unused, struct g_geom *gp)
3200 {
3201 	struct g_mirror_softc *sc;
3202 	int error;
3203 
3204 	g_topology_unlock();
3205 	sc = gp->softc;
3206 	sx_xlock(&sc->sc_lock);
3207 	g_cancel_event(sc);
3208 	error = g_mirror_destroy(gp->softc, G_MIRROR_DESTROY_SOFT);
3209 	if (error != 0)
3210 		sx_xunlock(&sc->sc_lock);
3211 	g_topology_lock();
3212 	return (error);
3213 }
3214 
3215 static void
3216 g_mirror_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
3217     struct g_consumer *cp, struct g_provider *pp)
3218 {
3219 	struct g_mirror_softc *sc;
3220 
3221 	g_topology_assert();
3222 
3223 	sc = gp->softc;
3224 	if (sc == NULL)
3225 		return;
3226 	/* Skip synchronization geom. */
3227 	if (gp == sc->sc_sync.ds_geom)
3228 		return;
3229 	if (pp != NULL) {
3230 		/* Nothing here. */
3231 	} else if (cp != NULL) {
3232 		struct g_mirror_disk *disk;
3233 
3234 		disk = cp->private;
3235 		if (disk == NULL)
3236 			return;
3237 		g_topology_unlock();
3238 		sx_xlock(&sc->sc_lock);
3239 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)disk->d_id);
3240 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
3241 			sbuf_printf(sb, "%s<Synchronized>", indent);
3242 			if (disk->d_sync.ds_offset == 0)
3243 				sbuf_printf(sb, "0%%");
3244 			else {
3245 				sbuf_printf(sb, "%u%%",
3246 				    (u_int)((disk->d_sync.ds_offset * 100) /
3247 				    sc->sc_provider->mediasize));
3248 			}
3249 			sbuf_printf(sb, "</Synchronized>\n");
3250 			if (disk->d_sync.ds_offset > 0) {
3251 				sbuf_printf(sb, "%s<BytesSynced>%jd"
3252 				    "</BytesSynced>\n", indent,
3253 				    (intmax_t)disk->d_sync.ds_offset);
3254 			}
3255 		}
3256 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent,
3257 		    disk->d_sync.ds_syncid);
3258 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent,
3259 		    disk->d_genid);
3260 		sbuf_printf(sb, "%s<Flags>", indent);
3261 		if (disk->d_flags == 0)
3262 			sbuf_printf(sb, "NONE");
3263 		else {
3264 			int first = 1;
3265 
3266 #define	ADD_FLAG(flag, name)	do {					\
3267 	if ((disk->d_flags & (flag)) != 0) {				\
3268 		if (!first)						\
3269 			sbuf_printf(sb, ", ");				\
3270 		else							\
3271 			first = 0;					\
3272 		sbuf_printf(sb, name);					\
3273 	}								\
3274 } while (0)
3275 			ADD_FLAG(G_MIRROR_DISK_FLAG_DIRTY, "DIRTY");
3276 			ADD_FLAG(G_MIRROR_DISK_FLAG_HARDCODED, "HARDCODED");
3277 			ADD_FLAG(G_MIRROR_DISK_FLAG_INACTIVE, "INACTIVE");
3278 			ADD_FLAG(G_MIRROR_DISK_FLAG_SYNCHRONIZING,
3279 			    "SYNCHRONIZING");
3280 			ADD_FLAG(G_MIRROR_DISK_FLAG_FORCE_SYNC, "FORCE_SYNC");
3281 			ADD_FLAG(G_MIRROR_DISK_FLAG_BROKEN, "BROKEN");
3282 #undef	ADD_FLAG
3283 		}
3284 		sbuf_printf(sb, "</Flags>\n");
3285 		sbuf_printf(sb, "%s<Priority>%u</Priority>\n", indent,
3286 		    disk->d_priority);
3287 		sbuf_printf(sb, "%s<State>%s</State>\n", indent,
3288 		    g_mirror_disk_state2str(disk->d_state));
3289 		sx_xunlock(&sc->sc_lock);
3290 		g_topology_lock();
3291 	} else {
3292 		g_topology_unlock();
3293 		sx_xlock(&sc->sc_lock);
3294 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)sc->sc_id);
3295 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent, sc->sc_syncid);
3296 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent, sc->sc_genid);
3297 		sbuf_printf(sb, "%s<Flags>", indent);
3298 		if (sc->sc_flags == 0)
3299 			sbuf_printf(sb, "NONE");
3300 		else {
3301 			int first = 1;
3302 
3303 #define	ADD_FLAG(flag, name)	do {					\
3304 	if ((sc->sc_flags & (flag)) != 0) {				\
3305 		if (!first)						\
3306 			sbuf_printf(sb, ", ");				\
3307 		else							\
3308 			first = 0;					\
3309 		sbuf_printf(sb, name);					\
3310 	}								\
3311 } while (0)
3312 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOFAILSYNC, "NOFAILSYNC");
3313 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOAUTOSYNC, "NOAUTOSYNC");
3314 #undef	ADD_FLAG
3315 		}
3316 		sbuf_printf(sb, "</Flags>\n");
3317 		sbuf_printf(sb, "%s<Slice>%u</Slice>\n", indent,
3318 		    (u_int)sc->sc_slice);
3319 		sbuf_printf(sb, "%s<Balance>%s</Balance>\n", indent,
3320 		    balance_name(sc->sc_balance));
3321 		sbuf_printf(sb, "%s<Components>%u</Components>\n", indent,
3322 		    sc->sc_ndisks);
3323 		sbuf_printf(sb, "%s<State>", indent);
3324 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
3325 			sbuf_printf(sb, "%s", "STARTING");
3326 		else if (sc->sc_ndisks ==
3327 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE))
3328 			sbuf_printf(sb, "%s", "COMPLETE");
3329 		else
3330 			sbuf_printf(sb, "%s", "DEGRADED");
3331 		sbuf_printf(sb, "</State>\n");
3332 		sx_xunlock(&sc->sc_lock);
3333 		g_topology_lock();
3334 	}
3335 }
3336 
3337 static void
3338 g_mirror_shutdown_post_sync(void *arg, int howto)
3339 {
3340 	struct g_class *mp;
3341 	struct g_geom *gp, *gp2;
3342 	struct g_mirror_softc *sc;
3343 	int error;
3344 
3345 	mp = arg;
3346 	g_topology_lock();
3347 	g_mirror_shutdown = 1;
3348 	LIST_FOREACH_SAFE(gp, &mp->geom, geom, gp2) {
3349 		if ((sc = gp->softc) == NULL)
3350 			continue;
3351 		/* Skip synchronization geom. */
3352 		if (gp == sc->sc_sync.ds_geom)
3353 			continue;
3354 		g_topology_unlock();
3355 		sx_xlock(&sc->sc_lock);
3356 		g_mirror_idle(sc, -1);
3357 		g_cancel_event(sc);
3358 		error = g_mirror_destroy(sc, G_MIRROR_DESTROY_DELAYED);
3359 		if (error != 0)
3360 			sx_xunlock(&sc->sc_lock);
3361 		g_topology_lock();
3362 	}
3363 	g_topology_unlock();
3364 }
3365 
3366 static void
3367 g_mirror_init(struct g_class *mp)
3368 {
3369 
3370 	g_mirror_post_sync = EVENTHANDLER_REGISTER(shutdown_post_sync,
3371 	    g_mirror_shutdown_post_sync, mp, SHUTDOWN_PRI_FIRST);
3372 	if (g_mirror_post_sync == NULL)
3373 		G_MIRROR_DEBUG(0, "Warning! Cannot register shutdown event.");
3374 }
3375 
3376 static void
3377 g_mirror_fini(struct g_class *mp)
3378 {
3379 
3380 	if (g_mirror_post_sync != NULL)
3381 		EVENTHANDLER_DEREGISTER(shutdown_post_sync, g_mirror_post_sync);
3382 }
3383 
3384 DECLARE_GEOM_CLASS(g_mirror_class, g_mirror);
3385