xref: /freebsd/sys/geom/mirror/g_mirror.c (revision 262e143bd46171a6415a5b28af260a5efa2a3db8)
1 /*-
2  * Copyright (c) 2004-2005 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/kernel.h>
33 #include <sys/module.h>
34 #include <sys/limits.h>
35 #include <sys/lock.h>
36 #include <sys/mutex.h>
37 #include <sys/bio.h>
38 #include <sys/sysctl.h>
39 #include <sys/malloc.h>
40 #include <sys/eventhandler.h>
41 #include <vm/uma.h>
42 #include <geom/geom.h>
43 #include <sys/proc.h>
44 #include <sys/kthread.h>
45 #include <sys/sched.h>
46 #include <geom/mirror/g_mirror.h>
47 
48 
49 static MALLOC_DEFINE(M_MIRROR, "mirror_data", "GEOM_MIRROR Data");
50 
51 SYSCTL_DECL(_kern_geom);
52 SYSCTL_NODE(_kern_geom, OID_AUTO, mirror, CTLFLAG_RW, 0, "GEOM_MIRROR stuff");
53 u_int g_mirror_debug = 0;
54 TUNABLE_INT("kern.geom.mirror.debug", &g_mirror_debug);
55 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, debug, CTLFLAG_RW, &g_mirror_debug, 0,
56     "Debug level");
57 static u_int g_mirror_timeout = 4;
58 TUNABLE_INT("kern.geom.mirror.timeout", &g_mirror_timeout);
59 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, timeout, CTLFLAG_RW, &g_mirror_timeout,
60     0, "Time to wait on all mirror components");
61 static u_int g_mirror_idletime = 5;
62 TUNABLE_INT("kern.geom.mirror.idletime", &g_mirror_idletime);
63 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, idletime, CTLFLAG_RW,
64     &g_mirror_idletime, 0, "Mark components as clean when idling");
65 static u_int g_mirror_reqs_per_sync = 5;
66 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, reqs_per_sync, CTLFLAG_RW,
67     &g_mirror_reqs_per_sync, 0,
68     "Number of regular I/O requests per synchronization request");
69 static u_int g_mirror_syncs_per_sec = 1000;
70 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, syncs_per_sec, CTLFLAG_RW,
71     &g_mirror_syncs_per_sec, 0,
72     "Number of synchronizations requests per second");
73 
74 #define	MSLEEP(ident, mtx, priority, wmesg, timeout)	do {		\
75 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, (ident));	\
76 	msleep((ident), (mtx), (priority), (wmesg), (timeout));		\
77 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, (ident));	\
78 } while (0)
79 
80 static eventhandler_tag g_mirror_ehtag = NULL;
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 void g_mirror_init(struct g_class *mp);
86 static void g_mirror_fini(struct g_class *mp);
87 
88 struct g_class g_mirror_class = {
89 	.name = G_MIRROR_CLASS_NAME,
90 	.version = G_VERSION,
91 	.ctlreq = g_mirror_config,
92 	.taste = g_mirror_taste,
93 	.destroy_geom = g_mirror_destroy_geom,
94 	.init = g_mirror_init,
95 	.fini = g_mirror_fini
96 };
97 
98 
99 static void g_mirror_destroy_provider(struct g_mirror_softc *sc);
100 static int g_mirror_update_disk(struct g_mirror_disk *disk, u_int state);
101 static void g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force);
102 static void g_mirror_dumpconf(struct sbuf *sb, const char *indent,
103     struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp);
104 static void g_mirror_sync_stop(struct g_mirror_disk *disk, int type);
105 
106 
107 static const char *
108 g_mirror_disk_state2str(int state)
109 {
110 
111 	switch (state) {
112 	case G_MIRROR_DISK_STATE_NONE:
113 		return ("NONE");
114 	case G_MIRROR_DISK_STATE_NEW:
115 		return ("NEW");
116 	case G_MIRROR_DISK_STATE_ACTIVE:
117 		return ("ACTIVE");
118 	case G_MIRROR_DISK_STATE_STALE:
119 		return ("STALE");
120 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
121 		return ("SYNCHRONIZING");
122 	case G_MIRROR_DISK_STATE_DISCONNECTED:
123 		return ("DISCONNECTED");
124 	case G_MIRROR_DISK_STATE_DESTROY:
125 		return ("DESTROY");
126 	default:
127 		return ("INVALID");
128 	}
129 }
130 
131 static const char *
132 g_mirror_device_state2str(int state)
133 {
134 
135 	switch (state) {
136 	case G_MIRROR_DEVICE_STATE_STARTING:
137 		return ("STARTING");
138 	case G_MIRROR_DEVICE_STATE_RUNNING:
139 		return ("RUNNING");
140 	default:
141 		return ("INVALID");
142 	}
143 }
144 
145 static const char *
146 g_mirror_get_diskname(struct g_mirror_disk *disk)
147 {
148 
149 	if (disk->d_consumer == NULL || disk->d_consumer->provider == NULL)
150 		return ("[unknown]");
151 	return (disk->d_name);
152 }
153 
154 /*
155  * --- Events handling functions ---
156  * Events in geom_mirror are used to maintain disks and device status
157  * from one thread to simplify locking.
158  */
159 static void
160 g_mirror_event_free(struct g_mirror_event *ep)
161 {
162 
163 	free(ep, M_MIRROR);
164 }
165 
166 int
167 g_mirror_event_send(void *arg, int state, int flags)
168 {
169 	struct g_mirror_softc *sc;
170 	struct g_mirror_disk *disk;
171 	struct g_mirror_event *ep;
172 	int error;
173 
174 	ep = malloc(sizeof(*ep), M_MIRROR, M_WAITOK);
175 	G_MIRROR_DEBUG(4, "%s: Sending event %p.", __func__, ep);
176 	if ((flags & G_MIRROR_EVENT_DEVICE) != 0) {
177 		disk = NULL;
178 		sc = arg;
179 	} else {
180 		disk = arg;
181 		sc = disk->d_softc;
182 	}
183 	ep->e_disk = disk;
184 	ep->e_state = state;
185 	ep->e_flags = flags;
186 	ep->e_error = 0;
187 	mtx_lock(&sc->sc_events_mtx);
188 	TAILQ_INSERT_TAIL(&sc->sc_events, ep, e_next);
189 	mtx_unlock(&sc->sc_events_mtx);
190 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
191 	mtx_lock(&sc->sc_queue_mtx);
192 	wakeup(sc);
193 	mtx_unlock(&sc->sc_queue_mtx);
194 	if ((flags & G_MIRROR_EVENT_DONTWAIT) != 0)
195 		return (0);
196 	g_topology_assert();
197 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, ep);
198 	g_topology_unlock();
199 	while ((ep->e_flags & G_MIRROR_EVENT_DONE) == 0) {
200 		mtx_lock(&sc->sc_events_mtx);
201 		MSLEEP(ep, &sc->sc_events_mtx, PRIBIO | PDROP, "m:event",
202 		    hz * 5);
203 	}
204 	/* Don't even try to use 'sc' here, because it could be already dead. */
205 	g_topology_lock();
206 	error = ep->e_error;
207 	g_mirror_event_free(ep);
208 	return (error);
209 }
210 
211 static struct g_mirror_event *
212 g_mirror_event_get(struct g_mirror_softc *sc)
213 {
214 	struct g_mirror_event *ep;
215 
216 	mtx_lock(&sc->sc_events_mtx);
217 	ep = TAILQ_FIRST(&sc->sc_events);
218 	mtx_unlock(&sc->sc_events_mtx);
219 	return (ep);
220 }
221 
222 static void
223 g_mirror_event_remove(struct g_mirror_softc *sc, struct g_mirror_event *ep)
224 {
225 
226 	mtx_lock(&sc->sc_events_mtx);
227 	TAILQ_REMOVE(&sc->sc_events, ep, e_next);
228 	mtx_unlock(&sc->sc_events_mtx);
229 }
230 
231 static void
232 g_mirror_event_cancel(struct g_mirror_disk *disk)
233 {
234 	struct g_mirror_softc *sc;
235 	struct g_mirror_event *ep, *tmpep;
236 
237 	g_topology_assert();
238 
239 	sc = disk->d_softc;
240 	mtx_lock(&sc->sc_events_mtx);
241 	TAILQ_FOREACH_SAFE(ep, &sc->sc_events, e_next, tmpep) {
242 		if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0)
243 			continue;
244 		if (ep->e_disk != disk)
245 			continue;
246 		TAILQ_REMOVE(&sc->sc_events, ep, e_next);
247 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
248 			g_mirror_event_free(ep);
249 		else {
250 			ep->e_error = ECANCELED;
251 			wakeup(ep);
252 		}
253 	}
254 	mtx_unlock(&sc->sc_events_mtx);
255 }
256 
257 /*
258  * Return the number of disks in given state.
259  * If state is equal to -1, count all connected disks.
260  */
261 u_int
262 g_mirror_ndisks(struct g_mirror_softc *sc, int state)
263 {
264 	struct g_mirror_disk *disk;
265 	u_int n = 0;
266 
267 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
268 		if (state == -1 || disk->d_state == state)
269 			n++;
270 	}
271 	return (n);
272 }
273 
274 /*
275  * Find a disk in mirror by its disk ID.
276  */
277 static struct g_mirror_disk *
278 g_mirror_id2disk(struct g_mirror_softc *sc, uint32_t id)
279 {
280 	struct g_mirror_disk *disk;
281 
282 	g_topology_assert();
283 
284 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
285 		if (disk->d_id == id)
286 			return (disk);
287 	}
288 	return (NULL);
289 }
290 
291 static u_int
292 g_mirror_nrequests(struct g_mirror_softc *sc, struct g_consumer *cp)
293 {
294 	struct bio *bp;
295 	u_int nreqs = 0;
296 
297 	mtx_lock(&sc->sc_queue_mtx);
298 	TAILQ_FOREACH(bp, &sc->sc_queue.queue, bio_queue) {
299 		if (bp->bio_from == cp)
300 			nreqs++;
301 	}
302 	mtx_unlock(&sc->sc_queue_mtx);
303 	return (nreqs);
304 }
305 
306 static int
307 g_mirror_is_busy(struct g_mirror_softc *sc, struct g_consumer *cp)
308 {
309 
310 	if (cp->index > 0) {
311 		G_MIRROR_DEBUG(2,
312 		    "I/O requests for %s exist, can't destroy it now.",
313 		    cp->provider->name);
314 		return (1);
315 	}
316 	if (g_mirror_nrequests(sc, cp) > 0) {
317 		G_MIRROR_DEBUG(2,
318 		    "I/O requests for %s in queue, can't destroy it now.",
319 		    cp->provider->name);
320 		return (1);
321 	}
322 	return (0);
323 }
324 
325 static void
326 g_mirror_destroy_consumer(void *arg, int flags __unused)
327 {
328 	struct g_consumer *cp;
329 
330 	cp = arg;
331 	G_MIRROR_DEBUG(1, "Consumer %s destroyed.", cp->provider->name);
332 	g_detach(cp);
333 	g_destroy_consumer(cp);
334 }
335 
336 static void
337 g_mirror_kill_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
338 {
339 	struct g_provider *pp;
340 	int retaste_wait;
341 
342 	g_topology_assert();
343 
344 	cp->private = NULL;
345 	if (g_mirror_is_busy(sc, cp))
346 		return;
347 	pp = cp->provider;
348 	retaste_wait = 0;
349 	if (cp->acw == 1) {
350 		if ((pp->geom->flags & G_GEOM_WITHER) == 0)
351 			retaste_wait = 1;
352 	}
353 	G_MIRROR_DEBUG(2, "Access %s r%dw%de%d = %d", pp->name, -cp->acr,
354 	    -cp->acw, -cp->ace, 0);
355 	if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
356 		g_access(cp, -cp->acr, -cp->acw, -cp->ace);
357 	if (retaste_wait) {
358 		/*
359 		 * After retaste event was send (inside g_access()), we can send
360 		 * event to detach and destroy consumer.
361 		 * A class, which has consumer to the given provider connected
362 		 * will not receive retaste event for the provider.
363 		 * This is the way how I ignore retaste events when I close
364 		 * consumers opened for write: I detach and destroy consumer
365 		 * after retaste event is sent.
366 		 */
367 		g_post_event(g_mirror_destroy_consumer, cp, M_WAITOK, NULL);
368 		return;
369 	}
370 	G_MIRROR_DEBUG(1, "Consumer %s destroyed.", pp->name);
371 	g_detach(cp);
372 	g_destroy_consumer(cp);
373 }
374 
375 static int
376 g_mirror_connect_disk(struct g_mirror_disk *disk, struct g_provider *pp)
377 {
378 	struct g_consumer *cp;
379 	int error;
380 
381 	g_topology_assert();
382 	KASSERT(disk->d_consumer == NULL,
383 	    ("Disk already connected (device %s).", disk->d_softc->sc_name));
384 
385 	cp = g_new_consumer(disk->d_softc->sc_geom);
386 	error = g_attach(cp, pp);
387 	if (error != 0) {
388 		g_destroy_consumer(cp);
389 		return (error);
390 	}
391 	error = g_access(cp, 1, 1, 1);
392 	if (error != 0) {
393 		g_detach(cp);
394 		g_destroy_consumer(cp);
395 		G_MIRROR_DEBUG(0, "Cannot open consumer %s (error=%d).",
396 		    pp->name, error);
397 		return (error);
398 	}
399 	disk->d_consumer = cp;
400 	disk->d_consumer->private = disk;
401 	disk->d_consumer->index = 0;
402 
403 	G_MIRROR_DEBUG(2, "Disk %s connected.", g_mirror_get_diskname(disk));
404 	return (0);
405 }
406 
407 static void
408 g_mirror_disconnect_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
409 {
410 
411 	g_topology_assert();
412 
413 	if (cp == NULL)
414 		return;
415 	if (cp->provider != NULL)
416 		g_mirror_kill_consumer(sc, cp);
417 	else
418 		g_destroy_consumer(cp);
419 }
420 
421 /*
422  * Initialize disk. This means allocate memory, create consumer, attach it
423  * to the provider and open access (r1w1e1) to it.
424  */
425 static struct g_mirror_disk *
426 g_mirror_init_disk(struct g_mirror_softc *sc, struct g_provider *pp,
427     struct g_mirror_metadata *md, int *errorp)
428 {
429 	struct g_mirror_disk *disk;
430 	int error;
431 
432 	disk = malloc(sizeof(*disk), M_MIRROR, M_NOWAIT | M_ZERO);
433 	if (disk == NULL) {
434 		error = ENOMEM;
435 		goto fail;
436 	}
437 	disk->d_softc = sc;
438 	error = g_mirror_connect_disk(disk, pp);
439 	if (error != 0)
440 		goto fail;
441 	disk->d_id = md->md_did;
442 	disk->d_state = G_MIRROR_DISK_STATE_NONE;
443 	disk->d_priority = md->md_priority;
444 	disk->d_delay.sec = 0;
445 	disk->d_delay.frac = 0;
446 	binuptime(&disk->d_last_used);
447 	disk->d_flags = md->md_dflags;
448 	if (md->md_provider[0] != '\0')
449 		disk->d_flags |= G_MIRROR_DISK_FLAG_HARDCODED;
450 	disk->d_sync.ds_consumer = NULL;
451 	disk->d_sync.ds_offset = md->md_sync_offset;
452 	disk->d_sync.ds_offset_done = md->md_sync_offset;
453 	disk->d_sync.ds_resync = -1;
454 	disk->d_genid = md->md_genid;
455 	disk->d_sync.ds_syncid = md->md_syncid;
456 	if (errorp != NULL)
457 		*errorp = 0;
458 	return (disk);
459 fail:
460 	if (errorp != NULL)
461 		*errorp = error;
462 	if (disk != NULL)
463 		free(disk, M_MIRROR);
464 	return (NULL);
465 }
466 
467 static void
468 g_mirror_destroy_disk(struct g_mirror_disk *disk)
469 {
470 	struct g_mirror_softc *sc;
471 
472 	g_topology_assert();
473 
474 	LIST_REMOVE(disk, d_next);
475 	g_mirror_event_cancel(disk);
476 	sc = disk->d_softc;
477 	if (sc->sc_hint == disk)
478 		sc->sc_hint = NULL;
479 	switch (disk->d_state) {
480 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
481 		g_mirror_sync_stop(disk, 1);
482 		/* FALLTHROUGH */
483 	case G_MIRROR_DISK_STATE_NEW:
484 	case G_MIRROR_DISK_STATE_STALE:
485 	case G_MIRROR_DISK_STATE_ACTIVE:
486 		g_mirror_disconnect_consumer(sc, disk->d_consumer);
487 		free(disk, M_MIRROR);
488 		break;
489 	default:
490 		KASSERT(0 == 1, ("Wrong disk state (%s, %s).",
491 		    g_mirror_get_diskname(disk),
492 		    g_mirror_disk_state2str(disk->d_state)));
493 	}
494 }
495 
496 static void
497 g_mirror_destroy_device(struct g_mirror_softc *sc)
498 {
499 	struct g_mirror_disk *disk;
500 	struct g_mirror_event *ep;
501 	struct g_geom *gp;
502 	struct g_consumer *cp, *tmpcp;
503 
504 	g_topology_assert();
505 
506 	gp = sc->sc_geom;
507 	if (sc->sc_provider != NULL)
508 		g_mirror_destroy_provider(sc);
509 	for (disk = LIST_FIRST(&sc->sc_disks); disk != NULL;
510 	    disk = LIST_FIRST(&sc->sc_disks)) {
511 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
512 		g_mirror_update_metadata(disk);
513 		g_mirror_destroy_disk(disk);
514 	}
515 	while ((ep = g_mirror_event_get(sc)) != NULL) {
516 		g_mirror_event_remove(sc, ep);
517 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
518 			g_mirror_event_free(ep);
519 		else {
520 			ep->e_error = ECANCELED;
521 			ep->e_flags |= G_MIRROR_EVENT_DONE;
522 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, ep);
523 			mtx_lock(&sc->sc_events_mtx);
524 			wakeup(ep);
525 			mtx_unlock(&sc->sc_events_mtx);
526 		}
527 	}
528 	callout_drain(&sc->sc_callout);
529 	gp->softc = NULL;
530 
531 	LIST_FOREACH_SAFE(cp, &sc->sc_sync.ds_geom->consumer, consumer, tmpcp) {
532 		g_mirror_disconnect_consumer(sc, cp);
533 	}
534 	sc->sc_sync.ds_geom->softc = NULL;
535 	g_wither_geom(sc->sc_sync.ds_geom, ENXIO);
536 	mtx_destroy(&sc->sc_queue_mtx);
537 	mtx_destroy(&sc->sc_events_mtx);
538 	G_MIRROR_DEBUG(0, "Device %s destroyed.", gp->name);
539 	g_wither_geom(gp, ENXIO);
540 }
541 
542 static void
543 g_mirror_orphan(struct g_consumer *cp)
544 {
545 	struct g_mirror_disk *disk;
546 
547 	g_topology_assert();
548 
549 	disk = cp->private;
550 	if (disk == NULL)
551 		return;
552 	disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
553 	g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
554 	    G_MIRROR_EVENT_DONTWAIT);
555 }
556 
557 /*
558  * Function should return the next active disk on the list.
559  * It is possible that it will be the same disk as given.
560  * If there are no active disks on list, NULL is returned.
561  */
562 static __inline struct g_mirror_disk *
563 g_mirror_find_next(struct g_mirror_softc *sc, struct g_mirror_disk *disk)
564 {
565 	struct g_mirror_disk *dp;
566 
567 	for (dp = LIST_NEXT(disk, d_next); dp != disk;
568 	    dp = LIST_NEXT(dp, d_next)) {
569 		if (dp == NULL)
570 			dp = LIST_FIRST(&sc->sc_disks);
571 		if (dp->d_state == G_MIRROR_DISK_STATE_ACTIVE)
572 			break;
573 	}
574 	if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
575 		return (NULL);
576 	return (dp);
577 }
578 
579 static struct g_mirror_disk *
580 g_mirror_get_disk(struct g_mirror_softc *sc)
581 {
582 	struct g_mirror_disk *disk;
583 
584 	if (sc->sc_hint == NULL) {
585 		sc->sc_hint = LIST_FIRST(&sc->sc_disks);
586 		if (sc->sc_hint == NULL)
587 			return (NULL);
588 	}
589 	disk = sc->sc_hint;
590 	if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE) {
591 		disk = g_mirror_find_next(sc, disk);
592 		if (disk == NULL)
593 			return (NULL);
594 	}
595 	sc->sc_hint = g_mirror_find_next(sc, disk);
596 	return (disk);
597 }
598 
599 static int
600 g_mirror_write_metadata(struct g_mirror_disk *disk,
601     struct g_mirror_metadata *md)
602 {
603 	struct g_mirror_softc *sc;
604 	struct g_consumer *cp;
605 	off_t offset, length;
606 	u_char *sector;
607 	int error = 0;
608 
609 	g_topology_assert();
610 
611 	sc = disk->d_softc;
612 	cp = disk->d_consumer;
613 	KASSERT(cp != NULL, ("NULL consumer (%s).", sc->sc_name));
614 	KASSERT(cp->provider != NULL, ("NULL provider (%s).", sc->sc_name));
615 	KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
616 	    ("Consumer %s closed? (r%dw%de%d).", cp->provider->name, cp->acr,
617 	    cp->acw, cp->ace));
618 	length = cp->provider->sectorsize;
619 	offset = cp->provider->mediasize - length;
620 	sector = malloc((size_t)length, M_MIRROR, M_WAITOK | M_ZERO);
621 	if (md != NULL)
622 		mirror_metadata_encode(md, sector);
623 	g_topology_unlock();
624 	error = g_write_data(cp, offset, sector, length);
625 	g_topology_lock();
626 	free(sector, M_MIRROR);
627 	if (error != 0) {
628 		disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_GENID;
629 		g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
630 		    G_MIRROR_EVENT_DONTWAIT);
631 	}
632 	return (error);
633 }
634 
635 static int
636 g_mirror_clear_metadata(struct g_mirror_disk *disk)
637 {
638 	int error;
639 
640 	g_topology_assert();
641 	error = g_mirror_write_metadata(disk, NULL);
642 	if (error == 0) {
643 		G_MIRROR_DEBUG(2, "Metadata on %s cleared.",
644 		    g_mirror_get_diskname(disk));
645 	} else {
646 		G_MIRROR_DEBUG(0,
647 		    "Cannot clear metadata on disk %s (error=%d).",
648 		    g_mirror_get_diskname(disk), error);
649 	}
650 	return (error);
651 }
652 
653 void
654 g_mirror_fill_metadata(struct g_mirror_softc *sc, struct g_mirror_disk *disk,
655     struct g_mirror_metadata *md)
656 {
657 
658 	strlcpy(md->md_magic, G_MIRROR_MAGIC, sizeof(md->md_magic));
659 	md->md_version = G_MIRROR_VERSION;
660 	strlcpy(md->md_name, sc->sc_name, sizeof(md->md_name));
661 	md->md_mid = sc->sc_id;
662 	md->md_all = sc->sc_ndisks;
663 	md->md_slice = sc->sc_slice;
664 	md->md_balance = sc->sc_balance;
665 	md->md_genid = sc->sc_genid;
666 	md->md_mediasize = sc->sc_mediasize;
667 	md->md_sectorsize = sc->sc_sectorsize;
668 	md->md_mflags = (sc->sc_flags & G_MIRROR_DEVICE_FLAG_MASK);
669 	bzero(md->md_provider, sizeof(md->md_provider));
670 	if (disk == NULL) {
671 		md->md_did = arc4random();
672 		md->md_priority = 0;
673 		md->md_syncid = 0;
674 		md->md_dflags = 0;
675 		md->md_sync_offset = 0;
676 		md->md_provsize = 0;
677 	} else {
678 		md->md_did = disk->d_id;
679 		md->md_priority = disk->d_priority;
680 		md->md_syncid = disk->d_sync.ds_syncid;
681 		md->md_dflags = (disk->d_flags & G_MIRROR_DISK_FLAG_MASK);
682 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
683 			md->md_sync_offset = disk->d_sync.ds_offset_done;
684 		else
685 			md->md_sync_offset = 0;
686 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_HARDCODED) != 0) {
687 			strlcpy(md->md_provider,
688 			    disk->d_consumer->provider->name,
689 			    sizeof(md->md_provider));
690 		}
691 		md->md_provsize = disk->d_consumer->provider->mediasize;
692 	}
693 }
694 
695 void
696 g_mirror_update_metadata(struct g_mirror_disk *disk)
697 {
698 	struct g_mirror_metadata md;
699 	int error;
700 
701 	g_topology_assert();
702 	g_mirror_fill_metadata(disk->d_softc, disk, &md);
703 	error = g_mirror_write_metadata(disk, &md);
704 	if (error == 0) {
705 		G_MIRROR_DEBUG(2, "Metadata on %s updated.",
706 		    g_mirror_get_diskname(disk));
707 	} else {
708 		G_MIRROR_DEBUG(0,
709 		    "Cannot update metadata on disk %s (error=%d).",
710 		    g_mirror_get_diskname(disk), error);
711 	}
712 }
713 
714 static void
715 g_mirror_bump_syncid(struct g_mirror_softc *sc)
716 {
717 	struct g_mirror_disk *disk;
718 
719 	g_topology_assert();
720 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
721 	    ("%s called with no active disks (device=%s).", __func__,
722 	    sc->sc_name));
723 
724 	sc->sc_syncid++;
725 	G_MIRROR_DEBUG(1, "Device %s: syncid bumped to %u.", sc->sc_name,
726 	    sc->sc_syncid);
727 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
728 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
729 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
730 			disk->d_sync.ds_syncid = sc->sc_syncid;
731 			g_mirror_update_metadata(disk);
732 		}
733 	}
734 }
735 
736 static void
737 g_mirror_bump_genid(struct g_mirror_softc *sc)
738 {
739 	struct g_mirror_disk *disk;
740 
741 	g_topology_assert();
742 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
743 	    ("%s called with no active disks (device=%s).", __func__,
744 	    sc->sc_name));
745 
746 	sc->sc_genid++;
747 	G_MIRROR_DEBUG(1, "Device %s: genid bumped to %u.", sc->sc_name,
748 	    sc->sc_genid);
749 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
750 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
751 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
752 			disk->d_genid = sc->sc_genid;
753 			g_mirror_update_metadata(disk);
754 		}
755 	}
756 }
757 
758 static void
759 g_mirror_idle(struct g_mirror_softc *sc)
760 {
761 	struct g_mirror_disk *disk;
762 
763 	if (sc->sc_provider == NULL || sc->sc_provider->acw == 0)
764 		return;
765 	sc->sc_idle = 1;
766 	g_topology_lock();
767 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
768 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
769 			continue;
770 		G_MIRROR_DEBUG(1, "Disk %s (device %s) marked as clean.",
771 		    g_mirror_get_diskname(disk), sc->sc_name);
772 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
773 		g_mirror_update_metadata(disk);
774 	}
775 	g_topology_unlock();
776 }
777 
778 static void
779 g_mirror_unidle(struct g_mirror_softc *sc)
780 {
781 	struct g_mirror_disk *disk;
782 
783 	sc->sc_idle = 0;
784 	g_topology_lock();
785 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
786 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
787 			continue;
788 		G_MIRROR_DEBUG(1, "Disk %s (device %s) marked as dirty.",
789 		    g_mirror_get_diskname(disk), sc->sc_name);
790 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
791 		g_mirror_update_metadata(disk);
792 	}
793 	g_topology_unlock();
794 }
795 
796 /*
797  * Return 1 if we should check if mirror is idling.
798  */
799 static int
800 g_mirror_check_idle(struct g_mirror_softc *sc)
801 {
802 	struct g_mirror_disk *disk;
803 
804 	if (sc->sc_idle)
805 		return (0);
806 	if (sc->sc_provider != NULL && sc->sc_provider->acw == 0)
807 		return (0);
808 	/*
809 	 * Check if there are no in-flight requests.
810 	 */
811 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
812 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
813 			continue;
814 		if (disk->d_consumer->index > 0)
815 			return (0);
816 	}
817 	return (1);
818 }
819 
820 static __inline int
821 bintime_cmp(struct bintime *bt1, struct bintime *bt2)
822 {
823 
824 	if (bt1->sec < bt2->sec)
825 		return (-1);
826 	else if (bt1->sec > bt2->sec)
827 		return (1);
828 	if (bt1->frac < bt2->frac)
829 		return (-1);
830 	else if (bt1->frac > bt2->frac)
831 		return (1);
832 	return (0);
833 }
834 
835 static void
836 g_mirror_update_delay(struct g_mirror_disk *disk, struct bio *bp)
837 {
838 
839 	if (disk->d_softc->sc_balance != G_MIRROR_BALANCE_LOAD)
840 		return;
841 	binuptime(&disk->d_delay);
842 	bintime_sub(&disk->d_delay, &bp->bio_t0);
843 }
844 
845 static void
846 g_mirror_done(struct bio *bp)
847 {
848 	struct g_mirror_softc *sc;
849 
850 	sc = bp->bio_from->geom->softc;
851 	bp->bio_cflags |= G_MIRROR_BIO_FLAG_REGULAR;
852 	mtx_lock(&sc->sc_queue_mtx);
853 	bioq_disksort(&sc->sc_queue, bp);
854 	wakeup(sc);
855 	mtx_unlock(&sc->sc_queue_mtx);
856 }
857 
858 static void
859 g_mirror_regular_request(struct bio *bp)
860 {
861 	struct g_mirror_softc *sc;
862 	struct g_mirror_disk *disk;
863 	struct bio *pbp;
864 
865 	g_topology_assert_not();
866 
867 	bp->bio_from->index--;
868 	pbp = bp->bio_parent;
869 	sc = pbp->bio_to->geom->softc;
870 	disk = bp->bio_from->private;
871 	if (disk == NULL) {
872 		g_topology_lock();
873 		g_mirror_kill_consumer(sc, bp->bio_from);
874 		g_topology_unlock();
875 	} else {
876 		g_mirror_update_delay(disk, bp);
877 	}
878 
879 	pbp->bio_inbed++;
880 	KASSERT(pbp->bio_inbed <= pbp->bio_children,
881 	    ("bio_inbed (%u) is bigger than bio_children (%u).", pbp->bio_inbed,
882 	    pbp->bio_children));
883 	if (bp->bio_error == 0 && pbp->bio_error == 0) {
884 		G_MIRROR_LOGREQ(3, bp, "Request delivered.");
885 		g_destroy_bio(bp);
886 		if (pbp->bio_children == pbp->bio_inbed) {
887 			G_MIRROR_LOGREQ(3, pbp, "Request delivered.");
888 			pbp->bio_completed = pbp->bio_length;
889 			g_io_deliver(pbp, pbp->bio_error);
890 		}
891 		return;
892 	} else if (bp->bio_error != 0) {
893 		if (pbp->bio_error == 0)
894 			pbp->bio_error = bp->bio_error;
895 		G_MIRROR_LOGREQ(0, bp, "Request failed (error=%d).",
896 		    bp->bio_error);
897 		if (disk != NULL) {
898 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
899 			g_mirror_event_send(disk,
900 			    G_MIRROR_DISK_STATE_DISCONNECTED,
901 			    G_MIRROR_EVENT_DONTWAIT);
902 		}
903 		switch (pbp->bio_cmd) {
904 		case BIO_DELETE:
905 		case BIO_WRITE:
906 			pbp->bio_inbed--;
907 			pbp->bio_children--;
908 			break;
909 		}
910 	}
911 	g_destroy_bio(bp);
912 
913 	switch (pbp->bio_cmd) {
914 	case BIO_READ:
915 		if (pbp->bio_children == pbp->bio_inbed) {
916 			pbp->bio_error = 0;
917 			mtx_lock(&sc->sc_queue_mtx);
918 			bioq_disksort(&sc->sc_queue, pbp);
919 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
920 			wakeup(sc);
921 			mtx_unlock(&sc->sc_queue_mtx);
922 		}
923 		break;
924 	case BIO_DELETE:
925 	case BIO_WRITE:
926 		if (pbp->bio_children == 0) {
927 			/*
928 			 * All requests failed.
929 			 */
930 		} else if (pbp->bio_inbed < pbp->bio_children) {
931 			/* Do nothing. */
932 			break;
933 		} else if (pbp->bio_children == pbp->bio_inbed) {
934 			/* Some requests succeeded. */
935 			pbp->bio_error = 0;
936 			pbp->bio_completed = pbp->bio_length;
937 		}
938 		g_io_deliver(pbp, pbp->bio_error);
939 		break;
940 	default:
941 		KASSERT(1 == 0, ("Invalid request: %u.", pbp->bio_cmd));
942 		break;
943 	}
944 }
945 
946 static void
947 g_mirror_sync_done(struct bio *bp)
948 {
949 	struct g_mirror_softc *sc;
950 
951 	G_MIRROR_LOGREQ(3, bp, "Synchronization request delivered.");
952 	sc = bp->bio_from->geom->softc;
953 	bp->bio_cflags |= G_MIRROR_BIO_FLAG_SYNC;
954 	mtx_lock(&sc->sc_queue_mtx);
955 	bioq_disksort(&sc->sc_queue, bp);
956 	wakeup(sc);
957 	mtx_unlock(&sc->sc_queue_mtx);
958 }
959 
960 static void
961 g_mirror_start(struct bio *bp)
962 {
963 	struct g_mirror_softc *sc;
964 
965 	sc = bp->bio_to->geom->softc;
966 	/*
967 	 * If sc == NULL or there are no valid disks, provider's error
968 	 * should be set and g_mirror_start() should not be called at all.
969 	 */
970 	KASSERT(sc != NULL && sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
971 	    ("Provider's error should be set (error=%d)(mirror=%s).",
972 	    bp->bio_to->error, bp->bio_to->name));
973 	G_MIRROR_LOGREQ(3, bp, "Request received.");
974 
975 	switch (bp->bio_cmd) {
976 	case BIO_READ:
977 	case BIO_WRITE:
978 	case BIO_DELETE:
979 		break;
980 	case BIO_GETATTR:
981 	default:
982 		g_io_deliver(bp, EOPNOTSUPP);
983 		return;
984 	}
985 	mtx_lock(&sc->sc_queue_mtx);
986 	bioq_disksort(&sc->sc_queue, bp);
987 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
988 	wakeup(sc);
989 	mtx_unlock(&sc->sc_queue_mtx);
990 }
991 
992 /*
993  * Send one synchronization request.
994  */
995 static void
996 g_mirror_sync_one(struct g_mirror_disk *disk)
997 {
998 	struct g_mirror_softc *sc;
999 	struct bio *bp;
1000 
1001 	sc = disk->d_softc;
1002 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
1003 	    ("Disk %s is not marked for synchronization.",
1004 	    g_mirror_get_diskname(disk)));
1005 
1006 	bp = g_new_bio();
1007 	if (bp == NULL)
1008 		return;
1009 	bp->bio_parent = NULL;
1010 	bp->bio_cmd = BIO_READ;
1011 	bp->bio_offset = disk->d_sync.ds_offset;
1012 	bp->bio_length = MIN(MAXPHYS, sc->sc_mediasize - bp->bio_offset);
1013 	bp->bio_cflags = 0;
1014 	bp->bio_done = g_mirror_sync_done;
1015 	bp->bio_data = disk->d_sync.ds_data;
1016 	if (bp->bio_data == NULL) {
1017 		g_destroy_bio(bp);
1018 		return;
1019 	}
1020 	disk->d_sync.ds_offset += bp->bio_length;
1021 	bp->bio_to = sc->sc_provider;
1022 	G_MIRROR_LOGREQ(3, bp, "Sending synchronization request.");
1023 	disk->d_sync.ds_consumer->index++;
1024 	g_io_request(bp, disk->d_sync.ds_consumer);
1025 }
1026 
1027 static void
1028 g_mirror_sync_request(struct bio *bp)
1029 {
1030 	struct g_mirror_softc *sc;
1031 	struct g_mirror_disk *disk;
1032 
1033 	bp->bio_from->index--;
1034 	sc = bp->bio_from->geom->softc;
1035 	disk = bp->bio_from->private;
1036 	if (disk == NULL) {
1037 		g_topology_lock();
1038 		g_mirror_kill_consumer(sc, bp->bio_from);
1039 		g_topology_unlock();
1040 		g_destroy_bio(bp);
1041 		return;
1042 	}
1043 
1044 	/*
1045 	 * Synchronization request.
1046 	 */
1047 	switch (bp->bio_cmd) {
1048 	case BIO_READ:
1049 	    {
1050 		struct g_consumer *cp;
1051 
1052 		if (bp->bio_error != 0) {
1053 			G_MIRROR_LOGREQ(0, bp,
1054 			    "Synchronization request failed (error=%d).",
1055 			    bp->bio_error);
1056 			g_destroy_bio(bp);
1057 			return;
1058 		}
1059 		G_MIRROR_LOGREQ(3, bp,
1060 		    "Synchronization request half-finished.");
1061 		bp->bio_cmd = BIO_WRITE;
1062 		bp->bio_cflags = 0;
1063 		cp = disk->d_consumer;
1064 		KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1065 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1066 		    cp->acr, cp->acw, cp->ace));
1067 		cp->index++;
1068 		g_io_request(bp, cp);
1069 		return;
1070 	    }
1071 	case BIO_WRITE:
1072 	    {
1073 		struct g_mirror_disk_sync *sync;
1074 
1075 		if (bp->bio_error != 0) {
1076 			G_MIRROR_LOGREQ(0, bp,
1077 			    "Synchronization request failed (error=%d).",
1078 			    bp->bio_error);
1079 			g_destroy_bio(bp);
1080 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
1081 			g_mirror_event_send(disk,
1082 			    G_MIRROR_DISK_STATE_DISCONNECTED,
1083 			    G_MIRROR_EVENT_DONTWAIT);
1084 			return;
1085 		}
1086 		G_MIRROR_LOGREQ(3, bp, "Synchronization request finished.");
1087 		sync = &disk->d_sync;
1088 		sync->ds_offset_done = bp->bio_offset + bp->bio_length;
1089 		g_destroy_bio(bp);
1090 		if (sync->ds_resync != -1)
1091 			break;
1092 		if (sync->ds_offset_done == sc->sc_provider->mediasize) {
1093 			/*
1094 			 * Disk up-to-date, activate it.
1095 			 */
1096 			g_mirror_event_send(disk, G_MIRROR_DISK_STATE_ACTIVE,
1097 			    G_MIRROR_EVENT_DONTWAIT);
1098 			return;
1099 		} else if (sync->ds_offset_done % (MAXPHYS * 100) == 0) {
1100 			/*
1101 			 * Update offset_done on every 100 blocks.
1102 			 * XXX: This should be configurable.
1103 			 */
1104 			g_topology_lock();
1105 			g_mirror_update_metadata(disk);
1106 			g_topology_unlock();
1107 		}
1108 		return;
1109 	    }
1110 	default:
1111 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1112 		    bp->bio_cmd, sc->sc_name));
1113 		break;
1114 	}
1115 }
1116 
1117 static void
1118 g_mirror_request_prefer(struct g_mirror_softc *sc, struct bio *bp)
1119 {
1120 	struct g_mirror_disk *disk;
1121 	struct g_consumer *cp;
1122 	struct bio *cbp;
1123 
1124 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1125 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE)
1126 			break;
1127 	}
1128 	if (disk == NULL) {
1129 		if (bp->bio_error == 0)
1130 			bp->bio_error = ENXIO;
1131 		g_io_deliver(bp, bp->bio_error);
1132 		return;
1133 	}
1134 	cbp = g_clone_bio(bp);
1135 	if (cbp == NULL) {
1136 		if (bp->bio_error == 0)
1137 			bp->bio_error = ENOMEM;
1138 		g_io_deliver(bp, bp->bio_error);
1139 		return;
1140 	}
1141 	/*
1142 	 * Fill in the component buf structure.
1143 	 */
1144 	cp = disk->d_consumer;
1145 	cbp->bio_done = g_mirror_done;
1146 	cbp->bio_to = cp->provider;
1147 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1148 	KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1149 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1150 	    cp->acw, cp->ace));
1151 	cp->index++;
1152 	g_io_request(cbp, cp);
1153 }
1154 
1155 static void
1156 g_mirror_request_round_robin(struct g_mirror_softc *sc, struct bio *bp)
1157 {
1158 	struct g_mirror_disk *disk;
1159 	struct g_consumer *cp;
1160 	struct bio *cbp;
1161 
1162 	disk = g_mirror_get_disk(sc);
1163 	if (disk == NULL) {
1164 		if (bp->bio_error == 0)
1165 			bp->bio_error = ENXIO;
1166 		g_io_deliver(bp, bp->bio_error);
1167 		return;
1168 	}
1169 	cbp = g_clone_bio(bp);
1170 	if (cbp == NULL) {
1171 		if (bp->bio_error == 0)
1172 			bp->bio_error = ENOMEM;
1173 		g_io_deliver(bp, bp->bio_error);
1174 		return;
1175 	}
1176 	/*
1177 	 * Fill in the component buf structure.
1178 	 */
1179 	cp = disk->d_consumer;
1180 	cbp->bio_done = g_mirror_done;
1181 	cbp->bio_to = cp->provider;
1182 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1183 	KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1184 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1185 	    cp->acw, cp->ace));
1186 	cp->index++;
1187 	g_io_request(cbp, cp);
1188 }
1189 
1190 static void
1191 g_mirror_request_load(struct g_mirror_softc *sc, struct bio *bp)
1192 {
1193 	struct g_mirror_disk *disk, *dp;
1194 	struct g_consumer *cp;
1195 	struct bio *cbp;
1196 	struct bintime curtime;
1197 
1198 	binuptime(&curtime);
1199 	/*
1200 	 * Find a disk which the smallest load.
1201 	 */
1202 	disk = NULL;
1203 	LIST_FOREACH(dp, &sc->sc_disks, d_next) {
1204 		if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1205 			continue;
1206 		/* If disk wasn't used for more than 2 sec, use it. */
1207 		if (curtime.sec - dp->d_last_used.sec >= 2) {
1208 			disk = dp;
1209 			break;
1210 		}
1211 		if (disk == NULL ||
1212 		    bintime_cmp(&dp->d_delay, &disk->d_delay) < 0) {
1213 			disk = dp;
1214 		}
1215 	}
1216 	KASSERT(disk != NULL, ("NULL disk for %s.", sc->sc_name));
1217 	cbp = g_clone_bio(bp);
1218 	if (cbp == NULL) {
1219 		if (bp->bio_error == 0)
1220 			bp->bio_error = ENOMEM;
1221 		g_io_deliver(bp, bp->bio_error);
1222 		return;
1223 	}
1224 	/*
1225 	 * Fill in the component buf structure.
1226 	 */
1227 	cp = disk->d_consumer;
1228 	cbp->bio_done = g_mirror_done;
1229 	cbp->bio_to = cp->provider;
1230 	binuptime(&disk->d_last_used);
1231 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1232 	KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1233 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1234 	    cp->acw, cp->ace));
1235 	cp->index++;
1236 	g_io_request(cbp, cp);
1237 }
1238 
1239 static void
1240 g_mirror_request_split(struct g_mirror_softc *sc, struct bio *bp)
1241 {
1242 	struct bio_queue_head queue;
1243 	struct g_mirror_disk *disk;
1244 	struct g_consumer *cp;
1245 	struct bio *cbp;
1246 	off_t left, mod, offset, slice;
1247 	u_char *data;
1248 	u_int ndisks;
1249 
1250 	if (bp->bio_length <= sc->sc_slice) {
1251 		g_mirror_request_round_robin(sc, bp);
1252 		return;
1253 	}
1254 	ndisks = g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE);
1255 	slice = bp->bio_length / ndisks;
1256 	mod = slice % sc->sc_provider->sectorsize;
1257 	if (mod != 0)
1258 		slice += sc->sc_provider->sectorsize - mod;
1259 	/*
1260 	 * Allocate all bios before sending any request, so we can
1261 	 * return ENOMEM in nice and clean way.
1262 	 */
1263 	left = bp->bio_length;
1264 	offset = bp->bio_offset;
1265 	data = bp->bio_data;
1266 	bioq_init(&queue);
1267 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1268 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1269 			continue;
1270 		cbp = g_clone_bio(bp);
1271 		if (cbp == NULL) {
1272 			for (cbp = bioq_first(&queue); cbp != NULL;
1273 			    cbp = bioq_first(&queue)) {
1274 				bioq_remove(&queue, cbp);
1275 				g_destroy_bio(cbp);
1276 			}
1277 			if (bp->bio_error == 0)
1278 				bp->bio_error = ENOMEM;
1279 			g_io_deliver(bp, bp->bio_error);
1280 			return;
1281 		}
1282 		bioq_insert_tail(&queue, cbp);
1283 		cbp->bio_done = g_mirror_done;
1284 		cbp->bio_caller1 = disk;
1285 		cbp->bio_to = disk->d_consumer->provider;
1286 		cbp->bio_offset = offset;
1287 		cbp->bio_data = data;
1288 		cbp->bio_length = MIN(left, slice);
1289 		left -= cbp->bio_length;
1290 		if (left == 0)
1291 			break;
1292 		offset += cbp->bio_length;
1293 		data += cbp->bio_length;
1294 	}
1295 	for (cbp = bioq_first(&queue); cbp != NULL; cbp = bioq_first(&queue)) {
1296 		bioq_remove(&queue, cbp);
1297 		G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1298 		disk = cbp->bio_caller1;
1299 		cbp->bio_caller1 = NULL;
1300 		cp = disk->d_consumer;
1301 		KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1302 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1303 		    cp->acr, cp->acw, cp->ace));
1304 		disk->d_consumer->index++;
1305 		g_io_request(cbp, disk->d_consumer);
1306 	}
1307 }
1308 
1309 static void
1310 g_mirror_register_request(struct bio *bp)
1311 {
1312 	struct g_mirror_softc *sc;
1313 
1314 	sc = bp->bio_to->geom->softc;
1315 	switch (bp->bio_cmd) {
1316 	case BIO_READ:
1317 		switch (sc->sc_balance) {
1318 		case G_MIRROR_BALANCE_LOAD:
1319 			g_mirror_request_load(sc, bp);
1320 			break;
1321 		case G_MIRROR_BALANCE_PREFER:
1322 			g_mirror_request_prefer(sc, bp);
1323 			break;
1324 		case G_MIRROR_BALANCE_ROUND_ROBIN:
1325 			g_mirror_request_round_robin(sc, bp);
1326 			break;
1327 		case G_MIRROR_BALANCE_SPLIT:
1328 			g_mirror_request_split(sc, bp);
1329 			break;
1330 		}
1331 		return;
1332 	case BIO_WRITE:
1333 	case BIO_DELETE:
1334 	    {
1335 		struct g_mirror_disk *disk;
1336 		struct g_mirror_disk_sync *sync;
1337 		struct bio_queue_head queue;
1338 		struct g_consumer *cp;
1339 		struct bio *cbp;
1340 
1341 		if (sc->sc_idle)
1342 			g_mirror_unidle(sc);
1343 		/*
1344 		 * Allocate all bios before sending any request, so we can
1345 		 * return ENOMEM in nice and clean way.
1346 		 */
1347 		bioq_init(&queue);
1348 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1349 			sync = &disk->d_sync;
1350 			switch (disk->d_state) {
1351 			case G_MIRROR_DISK_STATE_ACTIVE:
1352 				break;
1353 			case G_MIRROR_DISK_STATE_SYNCHRONIZING:
1354 				if (bp->bio_offset >= sync->ds_offset)
1355 					continue;
1356 				else if (bp->bio_offset + bp->bio_length >
1357 				    sync->ds_offset_done &&
1358 				    (bp->bio_offset < sync->ds_resync ||
1359 				     sync->ds_resync == -1)) {
1360 					sync->ds_resync = bp->bio_offset -
1361 					    (bp->bio_offset % MAXPHYS);
1362 				}
1363 				break;
1364 			default:
1365 				continue;
1366 			}
1367 			cbp = g_clone_bio(bp);
1368 			if (cbp == NULL) {
1369 				for (cbp = bioq_first(&queue); cbp != NULL;
1370 				    cbp = bioq_first(&queue)) {
1371 					bioq_remove(&queue, cbp);
1372 					g_destroy_bio(cbp);
1373 				}
1374 				if (bp->bio_error == 0)
1375 					bp->bio_error = ENOMEM;
1376 				g_io_deliver(bp, bp->bio_error);
1377 				return;
1378 			}
1379 			bioq_insert_tail(&queue, cbp);
1380 			cbp->bio_done = g_mirror_done;
1381 			cp = disk->d_consumer;
1382 			cbp->bio_caller1 = cp;
1383 			cbp->bio_to = cp->provider;
1384 			KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1385 			    ("Consumer %s not opened (r%dw%de%d).",
1386 			    cp->provider->name, cp->acr, cp->acw, cp->ace));
1387 		}
1388 		for (cbp = bioq_first(&queue); cbp != NULL;
1389 		    cbp = bioq_first(&queue)) {
1390 			bioq_remove(&queue, cbp);
1391 			G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1392 			cp = cbp->bio_caller1;
1393 			cbp->bio_caller1 = NULL;
1394 			cp->index++;
1395 			g_io_request(cbp, cp);
1396 		}
1397 		/*
1398 		 * Bump syncid on first write.
1399 		 */
1400 		if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0) {
1401 			sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
1402 			g_topology_lock();
1403 			g_mirror_bump_syncid(sc);
1404 			g_topology_unlock();
1405 		}
1406 		return;
1407 	    }
1408 	default:
1409 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1410 		    bp->bio_cmd, sc->sc_name));
1411 		break;
1412 	}
1413 }
1414 
1415 static int
1416 g_mirror_can_destroy(struct g_mirror_softc *sc)
1417 {
1418 	struct g_geom *gp;
1419 	struct g_consumer *cp;
1420 
1421 	g_topology_assert();
1422 	gp = sc->sc_geom;
1423 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1424 		if (g_mirror_is_busy(sc, cp))
1425 			return (0);
1426 	}
1427 	gp = sc->sc_sync.ds_geom;
1428 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1429 		if (g_mirror_is_busy(sc, cp))
1430 			return (0);
1431 	}
1432 	G_MIRROR_DEBUG(2, "No I/O requests for %s, it can be destroyed.",
1433 	    sc->sc_name);
1434 	return (1);
1435 }
1436 
1437 static int
1438 g_mirror_try_destroy(struct g_mirror_softc *sc)
1439 {
1440 
1441 	if (sc->sc_rootmount != NULL) {
1442 		G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p", __LINE__,
1443 		    sc->sc_rootmount);
1444 		root_mount_rel(sc->sc_rootmount);
1445 		sc->sc_rootmount = NULL;
1446 	}
1447 	g_topology_lock();
1448 	if (!g_mirror_can_destroy(sc)) {
1449 		g_topology_unlock();
1450 		return (0);
1451 	}
1452 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_WAIT) != 0) {
1453 		g_topology_unlock();
1454 		G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1455 		    &sc->sc_worker);
1456 		wakeup(&sc->sc_worker);
1457 		sc->sc_worker = NULL;
1458 	} else {
1459 		g_mirror_destroy_device(sc);
1460 		g_topology_unlock();
1461 		free(sc, M_MIRROR);
1462 	}
1463 	return (1);
1464 }
1465 
1466 /*
1467  * Worker thread.
1468  */
1469 static void
1470 g_mirror_worker(void *arg)
1471 {
1472 	struct g_mirror_softc *sc;
1473 	struct g_mirror_disk *disk;
1474 	struct g_mirror_disk_sync *sync;
1475 	struct g_mirror_event *ep;
1476 	struct bio *bp;
1477 	u_int nreqs;
1478 
1479 	sc = arg;
1480 	mtx_lock_spin(&sched_lock);
1481 	sched_prio(curthread, PRIBIO);
1482 	mtx_unlock_spin(&sched_lock);
1483 
1484 	nreqs = 0;
1485 	for (;;) {
1486 		G_MIRROR_DEBUG(5, "%s: Let's see...", __func__);
1487 		/*
1488 		 * First take a look at events.
1489 		 * This is important to handle events before any I/O requests.
1490 		 */
1491 		ep = g_mirror_event_get(sc);
1492 		if (ep != NULL && g_topology_try_lock()) {
1493 			g_mirror_event_remove(sc, ep);
1494 			if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0) {
1495 				/* Update only device status. */
1496 				G_MIRROR_DEBUG(3,
1497 				    "Running event for device %s.",
1498 				    sc->sc_name);
1499 				ep->e_error = 0;
1500 				g_mirror_update_device(sc, 1);
1501 			} else {
1502 				/* Update disk status. */
1503 				G_MIRROR_DEBUG(3, "Running event for disk %s.",
1504 				     g_mirror_get_diskname(ep->e_disk));
1505 				ep->e_error = g_mirror_update_disk(ep->e_disk,
1506 				    ep->e_state);
1507 				if (ep->e_error == 0)
1508 					g_mirror_update_device(sc, 0);
1509 			}
1510 			g_topology_unlock();
1511 			if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0) {
1512 				KASSERT(ep->e_error == 0,
1513 				    ("Error cannot be handled."));
1514 				g_mirror_event_free(ep);
1515 			} else {
1516 				ep->e_flags |= G_MIRROR_EVENT_DONE;
1517 				G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1518 				    ep);
1519 				mtx_lock(&sc->sc_events_mtx);
1520 				wakeup(ep);
1521 				mtx_unlock(&sc->sc_events_mtx);
1522 			}
1523 			if ((sc->sc_flags &
1524 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1525 				if (g_mirror_try_destroy(sc))
1526 					kthread_exit(0);
1527 			}
1528 			G_MIRROR_DEBUG(5, "%s: I'm here 1.", __func__);
1529 			continue;
1530 		}
1531 		/*
1532 		 * Now I/O requests.
1533 		 */
1534 		/* Get first request from the queue. */
1535 		mtx_lock(&sc->sc_queue_mtx);
1536 		bp = bioq_first(&sc->sc_queue);
1537 		if (bp == NULL) {
1538 			if (ep != NULL) {
1539 				/*
1540 				 * No I/O requests and topology lock was
1541 				 * already held? Try again.
1542 				 */
1543 				mtx_unlock(&sc->sc_queue_mtx);
1544 				continue;
1545 			}
1546 			if ((sc->sc_flags &
1547 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1548 				mtx_unlock(&sc->sc_queue_mtx);
1549 				if (g_mirror_try_destroy(sc))
1550 					kthread_exit(0);
1551 				mtx_lock(&sc->sc_queue_mtx);
1552 			}
1553 		}
1554 		if (sc->sc_sync.ds_ndisks > 0 &&
1555 		    (bp == NULL || nreqs > g_mirror_reqs_per_sync)) {
1556 			mtx_unlock(&sc->sc_queue_mtx);
1557 			/*
1558 			 * It is time for synchronization...
1559 			 */
1560 			nreqs = 0;
1561 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1562 				if (disk->d_state !=
1563 				    G_MIRROR_DISK_STATE_SYNCHRONIZING) {
1564 					continue;
1565 				}
1566 				sync = &disk->d_sync;
1567 				if (sync->ds_offset >=
1568 				    sc->sc_provider->mediasize) {
1569 					continue;
1570 				}
1571 				if (sync->ds_offset > sync->ds_offset_done)
1572 					continue;
1573 				if (sync->ds_resync != -1) {
1574 					sync->ds_offset = sync->ds_resync;
1575 					sync->ds_offset_done = sync->ds_resync;
1576 					sync->ds_resync = -1;
1577 				}
1578 				g_mirror_sync_one(disk);
1579 			}
1580 			G_MIRROR_DEBUG(5, "%s: I'm here 2.", __func__);
1581 			goto sleep;
1582 		}
1583 		if (bp == NULL) {
1584 			if (g_mirror_check_idle(sc)) {
1585 				u_int idletime;
1586 
1587 				idletime = g_mirror_idletime;
1588 				if (idletime == 0)
1589 					idletime = 1;
1590 				idletime *= hz;
1591 				if (msleep(sc, &sc->sc_queue_mtx, PRIBIO | PDROP,
1592 				    "m:w1", idletime) == EWOULDBLOCK) {
1593 					G_MIRROR_DEBUG(5, "%s: I'm here 3.",
1594 					    __func__);
1595 					/*
1596 					 * No I/O requests in 'idletime' seconds,
1597 					 * so mark components as clean.
1598 					 */
1599 					g_mirror_idle(sc);
1600 				}
1601 				G_MIRROR_DEBUG(5, "%s: I'm here 4.", __func__);
1602 			} else {
1603 				MSLEEP(sc, &sc->sc_queue_mtx, PRIBIO | PDROP,
1604 				    "m:w2", 0);
1605 				G_MIRROR_DEBUG(5, "%s: I'm here 5.", __func__);
1606 			}
1607 			continue;
1608 		}
1609 		nreqs++;
1610 		bioq_remove(&sc->sc_queue, bp);
1611 		mtx_unlock(&sc->sc_queue_mtx);
1612 
1613 		if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_REGULAR) != 0) {
1614 			g_mirror_regular_request(bp);
1615 		} else if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0) {
1616 			u_int timeout, sps;
1617 
1618 			g_mirror_sync_request(bp);
1619 sleep:
1620 			sps = g_mirror_syncs_per_sec;
1621 			if (sps == 0) {
1622 				G_MIRROR_DEBUG(5, "%s: I'm here 6.", __func__);
1623 				continue;
1624 			}
1625 			if (ep != NULL) {
1626 				/*
1627 				 * We have some pending events, don't sleep now.
1628 				 */
1629 				G_MIRROR_DEBUG(5, "%s: I'm here 7.", __func__);
1630 				continue;
1631 			}
1632 			mtx_lock(&sc->sc_queue_mtx);
1633 			if (bioq_first(&sc->sc_queue) != NULL) {
1634 				mtx_unlock(&sc->sc_queue_mtx);
1635 				G_MIRROR_DEBUG(5, "%s: I'm here 8.", __func__);
1636 				continue;
1637 			}
1638 			timeout = hz / sps;
1639 			if (timeout == 0)
1640 				timeout = 1;
1641 			MSLEEP(sc, &sc->sc_queue_mtx, PRIBIO | PDROP, "m:w3",
1642 			    timeout);
1643 		} else {
1644 			g_mirror_register_request(bp);
1645 		}
1646 		G_MIRROR_DEBUG(5, "%s: I'm here 9.", __func__);
1647 	}
1648 }
1649 
1650 /*
1651  * Open disk's consumer if needed.
1652  */
1653 static void
1654 g_mirror_update_access(struct g_mirror_disk *disk)
1655 {
1656 	struct g_provider *pp;
1657 
1658 	g_topology_assert();
1659 
1660 	pp = disk->d_softc->sc_provider;
1661 	if (pp == NULL)
1662 		return;
1663 	if (pp->acw > 0) {
1664 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) == 0) {
1665 			G_MIRROR_DEBUG(1,
1666 			    "Disk %s (device %s) marked as dirty.",
1667 			    g_mirror_get_diskname(disk),
1668 			    disk->d_softc->sc_name);
1669 			disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1670 		}
1671 	} else if (pp->acw == 0) {
1672 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
1673 			G_MIRROR_DEBUG(1,
1674 			    "Disk %s (device %s) marked as clean.",
1675 			    g_mirror_get_diskname(disk),
1676 			    disk->d_softc->sc_name);
1677 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
1678 		}
1679 	}
1680 }
1681 
1682 static void
1683 g_mirror_sync_start(struct g_mirror_disk *disk)
1684 {
1685 	struct g_mirror_softc *sc;
1686 	int error;
1687 
1688 	g_topology_assert();
1689 
1690 	sc = disk->d_softc;
1691 	KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
1692 	    ("Device not in RUNNING state (%s, %u).", sc->sc_name,
1693 	    sc->sc_state));
1694 
1695 	G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s.", sc->sc_name,
1696 	    g_mirror_get_diskname(disk));
1697 	disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1698 	KASSERT(disk->d_sync.ds_consumer == NULL,
1699 	    ("Sync consumer already exists (device=%s, disk=%s).",
1700 	    sc->sc_name, g_mirror_get_diskname(disk)));
1701 	disk->d_sync.ds_consumer = g_new_consumer(sc->sc_sync.ds_geom);
1702 	disk->d_sync.ds_consumer->private = disk;
1703 	disk->d_sync.ds_consumer->index = 0;
1704 	error = g_attach(disk->d_sync.ds_consumer, disk->d_softc->sc_provider);
1705 	KASSERT(error == 0, ("Cannot attach to %s (error=%d).",
1706 	    disk->d_softc->sc_name, error));
1707 	error = g_access(disk->d_sync.ds_consumer, 1, 0, 0);
1708 	KASSERT(error == 0, ("Cannot open %s (error=%d).",
1709 	    disk->d_softc->sc_name, error));
1710 	disk->d_sync.ds_data = malloc(MAXPHYS, M_MIRROR, M_WAITOK);
1711 	sc->sc_sync.ds_ndisks++;
1712 }
1713 
1714 /*
1715  * Stop synchronization process.
1716  * type: 0 - synchronization finished
1717  *       1 - synchronization stopped
1718  */
1719 static void
1720 g_mirror_sync_stop(struct g_mirror_disk *disk, int type)
1721 {
1722 
1723 	g_topology_assert();
1724 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
1725 	    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
1726 	    g_mirror_disk_state2str(disk->d_state)));
1727 	if (disk->d_sync.ds_consumer == NULL)
1728 		return;
1729 
1730 	if (type == 0) {
1731 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s finished.",
1732 		    disk->d_softc->sc_name, g_mirror_get_diskname(disk));
1733 	} else /* if (type == 1) */ {
1734 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s stopped.",
1735 		    disk->d_softc->sc_name, g_mirror_get_diskname(disk));
1736 	}
1737 	g_mirror_kill_consumer(disk->d_softc, disk->d_sync.ds_consumer);
1738 	free(disk->d_sync.ds_data, M_MIRROR);
1739 	disk->d_sync.ds_consumer = NULL;
1740 	disk->d_softc->sc_sync.ds_ndisks--;
1741 	disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
1742 }
1743 
1744 static void
1745 g_mirror_launch_provider(struct g_mirror_softc *sc)
1746 {
1747 	struct g_mirror_disk *disk;
1748 	struct g_provider *pp;
1749 
1750 	g_topology_assert();
1751 
1752 	pp = g_new_providerf(sc->sc_geom, "mirror/%s", sc->sc_name);
1753 	pp->mediasize = sc->sc_mediasize;
1754 	pp->sectorsize = sc->sc_sectorsize;
1755 	sc->sc_provider = pp;
1756 	g_error_provider(pp, 0);
1757 	G_MIRROR_DEBUG(0, "Device %s: provider %s launched.", sc->sc_name,
1758 	    pp->name);
1759 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1760 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
1761 			g_mirror_sync_start(disk);
1762 	}
1763 }
1764 
1765 static void
1766 g_mirror_destroy_provider(struct g_mirror_softc *sc)
1767 {
1768 	struct g_mirror_disk *disk;
1769 	struct bio *bp;
1770 
1771 	g_topology_assert();
1772 	KASSERT(sc->sc_provider != NULL, ("NULL provider (device=%s).",
1773 	    sc->sc_name));
1774 
1775 	g_error_provider(sc->sc_provider, ENXIO);
1776 	mtx_lock(&sc->sc_queue_mtx);
1777 	while ((bp = bioq_first(&sc->sc_queue)) != NULL) {
1778 		bioq_remove(&sc->sc_queue, bp);
1779 		g_io_deliver(bp, ENXIO);
1780 	}
1781 	mtx_unlock(&sc->sc_queue_mtx);
1782 	G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.", sc->sc_name,
1783 	    sc->sc_provider->name);
1784 	sc->sc_provider->flags |= G_PF_WITHER;
1785 	g_orphan_provider(sc->sc_provider, ENXIO);
1786 	sc->sc_provider = NULL;
1787 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1788 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
1789 			g_mirror_sync_stop(disk, 1);
1790 	}
1791 }
1792 
1793 static void
1794 g_mirror_go(void *arg)
1795 {
1796 	struct g_mirror_softc *sc;
1797 
1798 	sc = arg;
1799 	G_MIRROR_DEBUG(0, "Force device %s start due to timeout.", sc->sc_name);
1800 	g_mirror_event_send(sc, 0,
1801 	    G_MIRROR_EVENT_DONTWAIT | G_MIRROR_EVENT_DEVICE);
1802 }
1803 
1804 static u_int
1805 g_mirror_determine_state(struct g_mirror_disk *disk)
1806 {
1807 	struct g_mirror_softc *sc;
1808 	u_int state;
1809 
1810 	sc = disk->d_softc;
1811 	if (sc->sc_syncid == disk->d_sync.ds_syncid) {
1812 		if ((disk->d_flags &
1813 		    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
1814 			/* Disk does not need synchronization. */
1815 			state = G_MIRROR_DISK_STATE_ACTIVE;
1816 		} else {
1817 			if ((sc->sc_flags &
1818 			     G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0  ||
1819 			    (disk->d_flags &
1820 			     G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
1821 				/*
1822 				 * We can start synchronization from
1823 				 * the stored offset.
1824 				 */
1825 				state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
1826 			} else {
1827 				state = G_MIRROR_DISK_STATE_STALE;
1828 			}
1829 		}
1830 	} else if (disk->d_sync.ds_syncid < sc->sc_syncid) {
1831 		/*
1832 		 * Reset all synchronization data for this disk,
1833 		 * because if it even was synchronized, it was
1834 		 * synchronized to disks with different syncid.
1835 		 */
1836 		disk->d_flags |= G_MIRROR_DISK_FLAG_SYNCHRONIZING;
1837 		disk->d_sync.ds_offset = 0;
1838 		disk->d_sync.ds_offset_done = 0;
1839 		disk->d_sync.ds_syncid = sc->sc_syncid;
1840 		if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
1841 		    (disk->d_flags & G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
1842 			state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
1843 		} else {
1844 			state = G_MIRROR_DISK_STATE_STALE;
1845 		}
1846 	} else /* if (sc->sc_syncid < disk->d_sync.ds_syncid) */ {
1847 		/*
1848 		 * Not good, NOT GOOD!
1849 		 * It means that mirror was started on stale disks
1850 		 * and more fresh disk just arrive.
1851 		 * If there were writes, mirror is fucked up, sorry.
1852 		 * I think the best choice here is don't touch
1853 		 * this disk and inform the user laudly.
1854 		 */
1855 		G_MIRROR_DEBUG(0, "Device %s was started before the freshest "
1856 		    "disk (%s) arrives!! It will not be connected to the "
1857 		    "running device.", sc->sc_name,
1858 		    g_mirror_get_diskname(disk));
1859 		g_mirror_destroy_disk(disk);
1860 		state = G_MIRROR_DISK_STATE_NONE;
1861 		/* Return immediately, because disk was destroyed. */
1862 		return (state);
1863 	}
1864 	G_MIRROR_DEBUG(3, "State for %s disk: %s.",
1865 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(state));
1866 	return (state);
1867 }
1868 
1869 /*
1870  * Update device state.
1871  */
1872 static void
1873 g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force)
1874 {
1875 	struct g_mirror_disk *disk;
1876 	u_int state;
1877 
1878 	g_topology_assert();
1879 
1880 	switch (sc->sc_state) {
1881 	case G_MIRROR_DEVICE_STATE_STARTING:
1882 	    {
1883 		struct g_mirror_disk *pdisk, *tdisk;
1884 		u_int dirty, ndisks, genid, syncid;
1885 
1886 		KASSERT(sc->sc_provider == NULL,
1887 		    ("Non-NULL provider in STARTING state (%s).", sc->sc_name));
1888 		/*
1889 		 * Are we ready? We are, if all disks are connected or
1890 		 * if we have any disks and 'force' is true.
1891 		 */
1892 		if ((force && g_mirror_ndisks(sc, -1) > 0) ||
1893 		    sc->sc_ndisks == g_mirror_ndisks(sc, -1)) {
1894 			;
1895 		} else if (g_mirror_ndisks(sc, -1) == 0) {
1896 			/*
1897 			 * Disks went down in starting phase, so destroy
1898 			 * device.
1899 			 */
1900 			callout_drain(&sc->sc_callout);
1901 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
1902 			G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p", __LINE__,
1903 			    sc->sc_rootmount);
1904 			root_mount_rel(sc->sc_rootmount);
1905 			sc->sc_rootmount = NULL;
1906 			return;
1907 		} else {
1908 			return;
1909 		}
1910 
1911 		/*
1912 		 * Activate all disks with the biggest syncid.
1913 		 */
1914 		if (force) {
1915 			/*
1916 			 * If 'force' is true, we have been called due to
1917 			 * timeout, so don't bother canceling timeout.
1918 			 */
1919 			ndisks = 0;
1920 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1921 				if ((disk->d_flags &
1922 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
1923 					ndisks++;
1924 				}
1925 			}
1926 			if (ndisks == 0) {
1927 				/* No valid disks found, destroy device. */
1928 				sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
1929 				G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p",
1930 				    __LINE__, sc->sc_rootmount);
1931 				root_mount_rel(sc->sc_rootmount);
1932 				sc->sc_rootmount = NULL;
1933 				return;
1934 			}
1935 		} else {
1936 			/* Cancel timeout. */
1937 			callout_drain(&sc->sc_callout);
1938 		}
1939 
1940 		/*
1941 		 * Find the biggest genid.
1942 		 */
1943 		genid = 0;
1944 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1945 			if (disk->d_genid > genid)
1946 				genid = disk->d_genid;
1947 		}
1948 		sc->sc_genid = genid;
1949 		/*
1950 		 * Remove all disks without the biggest genid.
1951 		 */
1952 		LIST_FOREACH_SAFE(disk, &sc->sc_disks, d_next, tdisk) {
1953 			if (disk->d_genid < genid) {
1954 				G_MIRROR_DEBUG(0,
1955 				    "Component %s (device %s) broken, skipping.",
1956 				    g_mirror_get_diskname(disk), sc->sc_name);
1957 				g_mirror_destroy_disk(disk);
1958 			}
1959 		}
1960 
1961 		/*
1962 		 * Find the biggest syncid.
1963 		 */
1964 		syncid = 0;
1965 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1966 			if (disk->d_sync.ds_syncid > syncid)
1967 				syncid = disk->d_sync.ds_syncid;
1968 		}
1969 
1970 		/*
1971 		 * Here we need to look for dirty disks and if all disks
1972 		 * with the biggest syncid are dirty, we have to choose
1973 		 * one with the biggest priority and rebuild the rest.
1974 		 */
1975 		/*
1976 		 * Find the number of dirty disks with the biggest syncid.
1977 		 * Find the number of disks with the biggest syncid.
1978 		 * While here, find a disk with the biggest priority.
1979 		 */
1980 		dirty = ndisks = 0;
1981 		pdisk = NULL;
1982 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1983 			if (disk->d_sync.ds_syncid != syncid)
1984 				continue;
1985 			if ((disk->d_flags &
1986 			    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
1987 				continue;
1988 			}
1989 			ndisks++;
1990 			if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
1991 				dirty++;
1992 				if (pdisk == NULL ||
1993 				    pdisk->d_priority < disk->d_priority) {
1994 					pdisk = disk;
1995 				}
1996 			}
1997 		}
1998 		if (dirty == 0) {
1999 			/* No dirty disks at all, great. */
2000 		} else if (dirty == ndisks) {
2001 			/*
2002 			 * Force synchronization for all dirty disks except one
2003 			 * with the biggest priority.
2004 			 */
2005 			KASSERT(pdisk != NULL, ("pdisk == NULL"));
2006 			G_MIRROR_DEBUG(1, "Using disk %s (device %s) as a "
2007 			    "master disk for synchronization.",
2008 			    g_mirror_get_diskname(pdisk), sc->sc_name);
2009 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2010 				if (disk->d_sync.ds_syncid != syncid)
2011 					continue;
2012 				if ((disk->d_flags &
2013 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2014 					continue;
2015 				}
2016 				KASSERT((disk->d_flags &
2017 				    G_MIRROR_DISK_FLAG_DIRTY) != 0,
2018 				    ("Disk %s isn't marked as dirty.",
2019 				    g_mirror_get_diskname(disk)));
2020 				/* Skip the disk with the biggest priority. */
2021 				if (disk == pdisk)
2022 					continue;
2023 				disk->d_sync.ds_syncid = 0;
2024 			}
2025 		} else if (dirty < ndisks) {
2026 			/*
2027 			 * Force synchronization for all dirty disks.
2028 			 * We have some non-dirty disks.
2029 			 */
2030 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2031 				if (disk->d_sync.ds_syncid != syncid)
2032 					continue;
2033 				if ((disk->d_flags &
2034 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2035 					continue;
2036 				}
2037 				if ((disk->d_flags &
2038 				    G_MIRROR_DISK_FLAG_DIRTY) == 0) {
2039 					continue;
2040 				}
2041 				disk->d_sync.ds_syncid = 0;
2042 			}
2043 		}
2044 
2045 		/* Reset hint. */
2046 		sc->sc_hint = NULL;
2047 		sc->sc_syncid = syncid;
2048 		if (force) {
2049 			/* Remember to bump syncid on first write. */
2050 			sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2051 		}
2052 		state = G_MIRROR_DEVICE_STATE_RUNNING;
2053 		G_MIRROR_DEBUG(1, "Device %s state changed from %s to %s.",
2054 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state),
2055 		    g_mirror_device_state2str(state));
2056 		sc->sc_state = state;
2057 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2058 			state = g_mirror_determine_state(disk);
2059 			g_mirror_event_send(disk, state,
2060 			    G_MIRROR_EVENT_DONTWAIT);
2061 			if (state == G_MIRROR_DISK_STATE_STALE)
2062 				sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2063 		}
2064 		break;
2065 	    }
2066 	case G_MIRROR_DEVICE_STATE_RUNNING:
2067 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 0 &&
2068 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2069 			/*
2070 			 * No active disks or no disks at all,
2071 			 * so destroy device.
2072 			 */
2073 			if (sc->sc_provider != NULL)
2074 				g_mirror_destroy_provider(sc);
2075 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2076 			break;
2077 		} else if (g_mirror_ndisks(sc,
2078 		    G_MIRROR_DISK_STATE_ACTIVE) > 0 &&
2079 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2080 			/*
2081 			 * We have active disks, launch provider if it doesn't
2082 			 * exist.
2083 			 */
2084 			if (sc->sc_provider == NULL)
2085 				g_mirror_launch_provider(sc);
2086 			if (sc->sc_rootmount != NULL) {
2087 				G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p",
2088 				    __LINE__, sc->sc_rootmount);
2089 				root_mount_rel(sc->sc_rootmount);
2090 				sc->sc_rootmount = NULL;
2091 			}
2092 		}
2093 		/*
2094 		 * Genid should be bumped immediately, so do it here.
2095 		 */
2096 		if ((sc->sc_bump_id & G_MIRROR_BUMP_GENID) != 0) {
2097 			sc->sc_bump_id &= ~G_MIRROR_BUMP_GENID;
2098 			g_mirror_bump_genid(sc);
2099 		}
2100 		break;
2101 	default:
2102 		KASSERT(1 == 0, ("Wrong device state (%s, %s).",
2103 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state)));
2104 		break;
2105 	}
2106 }
2107 
2108 /*
2109  * Update disk state and device state if needed.
2110  */
2111 #define	DISK_STATE_CHANGED()	G_MIRROR_DEBUG(1,			\
2112 	"Disk %s state changed from %s to %s (device %s).",		\
2113 	g_mirror_get_diskname(disk),					\
2114 	g_mirror_disk_state2str(disk->d_state),				\
2115 	g_mirror_disk_state2str(state), sc->sc_name)
2116 static int
2117 g_mirror_update_disk(struct g_mirror_disk *disk, u_int state)
2118 {
2119 	struct g_mirror_softc *sc;
2120 
2121 	g_topology_assert();
2122 
2123 	sc = disk->d_softc;
2124 again:
2125 	G_MIRROR_DEBUG(3, "Changing disk %s state from %s to %s.",
2126 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(disk->d_state),
2127 	    g_mirror_disk_state2str(state));
2128 	switch (state) {
2129 	case G_MIRROR_DISK_STATE_NEW:
2130 		/*
2131 		 * Possible scenarios:
2132 		 * 1. New disk arrive.
2133 		 */
2134 		/* Previous state should be NONE. */
2135 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NONE,
2136 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2137 		    g_mirror_disk_state2str(disk->d_state)));
2138 		DISK_STATE_CHANGED();
2139 
2140 		disk->d_state = state;
2141 		if (LIST_EMPTY(&sc->sc_disks))
2142 			LIST_INSERT_HEAD(&sc->sc_disks, disk, d_next);
2143 		else {
2144 			struct g_mirror_disk *dp;
2145 
2146 			LIST_FOREACH(dp, &sc->sc_disks, d_next) {
2147 				if (disk->d_priority >= dp->d_priority) {
2148 					LIST_INSERT_BEFORE(dp, disk, d_next);
2149 					dp = NULL;
2150 					break;
2151 				}
2152 				if (LIST_NEXT(dp, d_next) == NULL)
2153 					break;
2154 			}
2155 			if (dp != NULL)
2156 				LIST_INSERT_AFTER(dp, disk, d_next);
2157 		}
2158 		G_MIRROR_DEBUG(0, "Device %s: provider %s detected.",
2159 		    sc->sc_name, g_mirror_get_diskname(disk));
2160 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
2161 			break;
2162 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2163 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2164 		    g_mirror_device_state2str(sc->sc_state),
2165 		    g_mirror_get_diskname(disk),
2166 		    g_mirror_disk_state2str(disk->d_state)));
2167 		state = g_mirror_determine_state(disk);
2168 		if (state != G_MIRROR_DISK_STATE_NONE)
2169 			goto again;
2170 		break;
2171 	case G_MIRROR_DISK_STATE_ACTIVE:
2172 		/*
2173 		 * Possible scenarios:
2174 		 * 1. New disk does not need synchronization.
2175 		 * 2. Synchronization process finished successfully.
2176 		 */
2177 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2178 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2179 		    g_mirror_device_state2str(sc->sc_state),
2180 		    g_mirror_get_diskname(disk),
2181 		    g_mirror_disk_state2str(disk->d_state)));
2182 		/* Previous state should be NEW or SYNCHRONIZING. */
2183 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW ||
2184 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2185 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2186 		    g_mirror_disk_state2str(disk->d_state)));
2187 		DISK_STATE_CHANGED();
2188 
2189 		if (disk->d_state == G_MIRROR_DISK_STATE_NEW)
2190 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2191 		else if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2192 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2193 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_FORCE_SYNC;
2194 			g_mirror_sync_stop(disk, 0);
2195 		}
2196 		disk->d_state = state;
2197 		disk->d_sync.ds_offset = 0;
2198 		disk->d_sync.ds_offset_done = 0;
2199 		g_mirror_update_access(disk);
2200 		g_mirror_update_metadata(disk);
2201 		G_MIRROR_DEBUG(0, "Device %s: provider %s activated.",
2202 		    sc->sc_name, g_mirror_get_diskname(disk));
2203 		break;
2204 	case G_MIRROR_DISK_STATE_STALE:
2205 		/*
2206 		 * Possible scenarios:
2207 		 * 1. Stale disk was connected.
2208 		 */
2209 		/* Previous state should be NEW. */
2210 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2211 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2212 		    g_mirror_disk_state2str(disk->d_state)));
2213 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2214 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2215 		    g_mirror_device_state2str(sc->sc_state),
2216 		    g_mirror_get_diskname(disk),
2217 		    g_mirror_disk_state2str(disk->d_state)));
2218 		/*
2219 		 * STALE state is only possible if device is marked
2220 		 * NOAUTOSYNC.
2221 		 */
2222 		KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) != 0,
2223 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2224 		    g_mirror_device_state2str(sc->sc_state),
2225 		    g_mirror_get_diskname(disk),
2226 		    g_mirror_disk_state2str(disk->d_state)));
2227 		DISK_STATE_CHANGED();
2228 
2229 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2230 		disk->d_state = state;
2231 		g_mirror_update_metadata(disk);
2232 		G_MIRROR_DEBUG(0, "Device %s: provider %s is stale.",
2233 		    sc->sc_name, g_mirror_get_diskname(disk));
2234 		break;
2235 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
2236 		/*
2237 		 * Possible scenarios:
2238 		 * 1. Disk which needs synchronization was connected.
2239 		 */
2240 		/* Previous state should be NEW. */
2241 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2242 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2243 		    g_mirror_disk_state2str(disk->d_state)));
2244 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2245 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2246 		    g_mirror_device_state2str(sc->sc_state),
2247 		    g_mirror_get_diskname(disk),
2248 		    g_mirror_disk_state2str(disk->d_state)));
2249 		DISK_STATE_CHANGED();
2250 
2251 		if (disk->d_state == G_MIRROR_DISK_STATE_NEW)
2252 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2253 		disk->d_state = state;
2254 		if (sc->sc_provider != NULL) {
2255 			g_mirror_sync_start(disk);
2256 			g_mirror_update_metadata(disk);
2257 		}
2258 		break;
2259 	case G_MIRROR_DISK_STATE_DISCONNECTED:
2260 		/*
2261 		 * Possible scenarios:
2262 		 * 1. Device wasn't running yet, but disk disappear.
2263 		 * 2. Disk was active and disapppear.
2264 		 * 3. Disk disappear during synchronization process.
2265 		 */
2266 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING) {
2267 			/*
2268 			 * Previous state should be ACTIVE, STALE or
2269 			 * SYNCHRONIZING.
2270 			 */
2271 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
2272 			    disk->d_state == G_MIRROR_DISK_STATE_STALE ||
2273 			    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2274 			    ("Wrong disk state (%s, %s).",
2275 			    g_mirror_get_diskname(disk),
2276 			    g_mirror_disk_state2str(disk->d_state)));
2277 		} else if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING) {
2278 			/* Previous state should be NEW. */
2279 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2280 			    ("Wrong disk state (%s, %s).",
2281 			    g_mirror_get_diskname(disk),
2282 			    g_mirror_disk_state2str(disk->d_state)));
2283 			/*
2284 			 * Reset bumping syncid if disk disappeared in STARTING
2285 			 * state.
2286 			 */
2287 			if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0)
2288 				sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
2289 #ifdef	INVARIANTS
2290 		} else {
2291 			KASSERT(1 == 0, ("Wrong device state (%s, %s, %s, %s).",
2292 			    sc->sc_name,
2293 			    g_mirror_device_state2str(sc->sc_state),
2294 			    g_mirror_get_diskname(disk),
2295 			    g_mirror_disk_state2str(disk->d_state)));
2296 #endif
2297 		}
2298 		DISK_STATE_CHANGED();
2299 		G_MIRROR_DEBUG(0, "Device %s: provider %s disconnected.",
2300 		    sc->sc_name, g_mirror_get_diskname(disk));
2301 
2302 		g_mirror_destroy_disk(disk);
2303 		break;
2304 	case G_MIRROR_DISK_STATE_DESTROY:
2305 	    {
2306 		int error;
2307 
2308 		error = g_mirror_clear_metadata(disk);
2309 		if (error != 0)
2310 			return (error);
2311 		DISK_STATE_CHANGED();
2312 		G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.",
2313 		    sc->sc_name, g_mirror_get_diskname(disk));
2314 
2315 		g_mirror_destroy_disk(disk);
2316 		sc->sc_ndisks--;
2317 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2318 			g_mirror_update_metadata(disk);
2319 		}
2320 		break;
2321 	    }
2322 	default:
2323 		KASSERT(1 == 0, ("Unknown state (%u).", state));
2324 		break;
2325 	}
2326 	return (0);
2327 }
2328 #undef	DISK_STATE_CHANGED
2329 
2330 int
2331 g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md)
2332 {
2333 	struct g_provider *pp;
2334 	u_char *buf;
2335 	int error;
2336 
2337 	g_topology_assert();
2338 
2339 	error = g_access(cp, 1, 0, 0);
2340 	if (error != 0)
2341 		return (error);
2342 	pp = cp->provider;
2343 	g_topology_unlock();
2344 	/* Metadata are stored on last sector. */
2345 	buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
2346 	    &error);
2347 	g_topology_lock();
2348 	g_access(cp, -1, 0, 0);
2349 	if (buf == NULL) {
2350 		G_MIRROR_DEBUG(1, "Cannot read metadata from %s (error=%d).",
2351 		    cp->provider->name, error);
2352 		if (buf != NULL)
2353 			g_free(buf);
2354 		return (error);
2355 	}
2356 
2357 	/* Decode metadata. */
2358 	error = mirror_metadata_decode(buf, md);
2359 	g_free(buf);
2360 	if (strcmp(md->md_magic, G_MIRROR_MAGIC) != 0)
2361 		return (EINVAL);
2362 	if (md->md_version > G_MIRROR_VERSION) {
2363 		G_MIRROR_DEBUG(0,
2364 		    "Kernel module is too old to handle metadata from %s.",
2365 		    cp->provider->name);
2366 		return (EINVAL);
2367 	}
2368 	if (error != 0) {
2369 		G_MIRROR_DEBUG(1, "MD5 metadata hash mismatch for provider %s.",
2370 		    cp->provider->name);
2371 		return (error);
2372 	}
2373 
2374 	return (0);
2375 }
2376 
2377 static int
2378 g_mirror_check_metadata(struct g_mirror_softc *sc, struct g_provider *pp,
2379     struct g_mirror_metadata *md)
2380 {
2381 
2382 	if (g_mirror_id2disk(sc, md->md_did) != NULL) {
2383 		G_MIRROR_DEBUG(1, "Disk %s (id=%u) already exists, skipping.",
2384 		    pp->name, md->md_did);
2385 		return (EEXIST);
2386 	}
2387 	if (md->md_all != sc->sc_ndisks) {
2388 		G_MIRROR_DEBUG(1,
2389 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2390 		    "md_all", pp->name, sc->sc_name);
2391 		return (EINVAL);
2392 	}
2393 	if (md->md_slice != sc->sc_slice) {
2394 		G_MIRROR_DEBUG(1,
2395 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2396 		    "md_slice", pp->name, sc->sc_name);
2397 		return (EINVAL);
2398 	}
2399 	if (md->md_balance != sc->sc_balance) {
2400 		G_MIRROR_DEBUG(1,
2401 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2402 		    "md_balance", pp->name, sc->sc_name);
2403 		return (EINVAL);
2404 	}
2405 	if (md->md_mediasize != sc->sc_mediasize) {
2406 		G_MIRROR_DEBUG(1,
2407 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2408 		    "md_mediasize", pp->name, sc->sc_name);
2409 		return (EINVAL);
2410 	}
2411 	if (sc->sc_mediasize > pp->mediasize) {
2412 		G_MIRROR_DEBUG(1,
2413 		    "Invalid size of disk %s (device %s), skipping.", pp->name,
2414 		    sc->sc_name);
2415 		return (EINVAL);
2416 	}
2417 	if (md->md_sectorsize != sc->sc_sectorsize) {
2418 		G_MIRROR_DEBUG(1,
2419 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2420 		    "md_sectorsize", pp->name, sc->sc_name);
2421 		return (EINVAL);
2422 	}
2423 	if ((sc->sc_sectorsize % pp->sectorsize) != 0) {
2424 		G_MIRROR_DEBUG(1,
2425 		    "Invalid sector size of disk %s (device %s), skipping.",
2426 		    pp->name, sc->sc_name);
2427 		return (EINVAL);
2428 	}
2429 	if ((md->md_mflags & ~G_MIRROR_DEVICE_FLAG_MASK) != 0) {
2430 		G_MIRROR_DEBUG(1,
2431 		    "Invalid device flags on disk %s (device %s), skipping.",
2432 		    pp->name, sc->sc_name);
2433 		return (EINVAL);
2434 	}
2435 	if ((md->md_dflags & ~G_MIRROR_DISK_FLAG_MASK) != 0) {
2436 		G_MIRROR_DEBUG(1,
2437 		    "Invalid disk flags on disk %s (device %s), skipping.",
2438 		    pp->name, sc->sc_name);
2439 		return (EINVAL);
2440 	}
2441 	return (0);
2442 }
2443 
2444 int
2445 g_mirror_add_disk(struct g_mirror_softc *sc, struct g_provider *pp,
2446     struct g_mirror_metadata *md)
2447 {
2448 	struct g_mirror_disk *disk;
2449 	int error;
2450 
2451 	g_topology_assert();
2452 	G_MIRROR_DEBUG(2, "Adding disk %s.", pp->name);
2453 
2454 	error = g_mirror_check_metadata(sc, pp, md);
2455 	if (error != 0)
2456 		return (error);
2457 	if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING &&
2458 	    md->md_genid < sc->sc_genid) {
2459 		G_MIRROR_DEBUG(0, "Component %s (device %s) broken, skipping.",
2460 		    pp->name, sc->sc_name);
2461 		return (EINVAL);
2462 	}
2463 	disk = g_mirror_init_disk(sc, pp, md, &error);
2464 	if (disk == NULL)
2465 		return (error);
2466 	error = g_mirror_event_send(disk, G_MIRROR_DISK_STATE_NEW,
2467 	    G_MIRROR_EVENT_WAIT);
2468 	if (error != 0)
2469 		return (error);
2470 	if (md->md_version < G_MIRROR_VERSION) {
2471 		G_MIRROR_DEBUG(0, "Upgrading metadata on %s (v%d->v%d).",
2472 		    pp->name, md->md_version, G_MIRROR_VERSION);
2473 		g_mirror_update_metadata(disk);
2474 	}
2475 	return (0);
2476 }
2477 
2478 static int
2479 g_mirror_access(struct g_provider *pp, int acr, int acw, int ace)
2480 {
2481 	struct g_mirror_softc *sc;
2482 	struct g_mirror_disk *disk;
2483 	int dcr, dcw, dce;
2484 
2485 	g_topology_assert();
2486 	G_MIRROR_DEBUG(2, "Access request for %s: r%dw%de%d.", pp->name, acr,
2487 	    acw, ace);
2488 
2489 	dcr = pp->acr + acr;
2490 	dcw = pp->acw + acw;
2491 	dce = pp->ace + ace;
2492 
2493 	sc = pp->geom->softc;
2494 	if (sc == NULL || LIST_EMPTY(&sc->sc_disks) ||
2495 	    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
2496 		if (acr <= 0 && acw <= 0 && ace <= 0)
2497 			return (0);
2498 		else
2499 			return (ENXIO);
2500 	}
2501 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2502 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
2503 			continue;
2504 		/*
2505 		 * Mark disk as dirty on open and unmark on close.
2506 		 */
2507 		if (pp->acw == 0 && dcw > 0) {
2508 			G_MIRROR_DEBUG(1,
2509 			    "Disk %s (device %s) marked as dirty.",
2510 			    g_mirror_get_diskname(disk), sc->sc_name);
2511 			disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
2512 			g_mirror_update_metadata(disk);
2513 		} else if (pp->acw > 0 && dcw == 0) {
2514 			G_MIRROR_DEBUG(1,
2515 			    "Disk %s (device %s) marked as clean.",
2516 			    g_mirror_get_diskname(disk), sc->sc_name);
2517 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2518 			g_mirror_update_metadata(disk);
2519 		}
2520 	}
2521 	return (0);
2522 }
2523 
2524 static struct g_geom *
2525 g_mirror_create(struct g_class *mp, const struct g_mirror_metadata *md)
2526 {
2527 	struct g_mirror_softc *sc;
2528 	struct g_geom *gp;
2529 	int error, timeout;
2530 
2531 	g_topology_assert();
2532 	G_MIRROR_DEBUG(1, "Creating device %s (id=%u).", md->md_name,
2533 	    md->md_mid);
2534 
2535 	/* One disk is minimum. */
2536 	if (md->md_all < 1)
2537 		return (NULL);
2538 	/*
2539 	 * Action geom.
2540 	 */
2541 	gp = g_new_geomf(mp, "%s", md->md_name);
2542 	sc = malloc(sizeof(*sc), M_MIRROR, M_WAITOK | M_ZERO);
2543 	gp->start = g_mirror_start;
2544 	gp->orphan = g_mirror_orphan;
2545 	gp->access = g_mirror_access;
2546 	gp->dumpconf = g_mirror_dumpconf;
2547 
2548 	sc->sc_id = md->md_mid;
2549 	sc->sc_slice = md->md_slice;
2550 	sc->sc_balance = md->md_balance;
2551 	sc->sc_mediasize = md->md_mediasize;
2552 	sc->sc_sectorsize = md->md_sectorsize;
2553 	sc->sc_ndisks = md->md_all;
2554 	sc->sc_flags = md->md_mflags;
2555 	sc->sc_bump_id = 0;
2556 	sc->sc_idle = 0;
2557 	bioq_init(&sc->sc_queue);
2558 	mtx_init(&sc->sc_queue_mtx, "gmirror:queue", NULL, MTX_DEF);
2559 	LIST_INIT(&sc->sc_disks);
2560 	TAILQ_INIT(&sc->sc_events);
2561 	mtx_init(&sc->sc_events_mtx, "gmirror:events", NULL, MTX_DEF);
2562 	callout_init(&sc->sc_callout, CALLOUT_MPSAFE);
2563 	sc->sc_state = G_MIRROR_DEVICE_STATE_STARTING;
2564 	gp->softc = sc;
2565 	sc->sc_geom = gp;
2566 	sc->sc_provider = NULL;
2567 	/*
2568 	 * Synchronization geom.
2569 	 */
2570 	gp = g_new_geomf(mp, "%s.sync", md->md_name);
2571 	gp->softc = sc;
2572 	gp->orphan = g_mirror_orphan;
2573 	sc->sc_sync.ds_geom = gp;
2574 	sc->sc_sync.ds_ndisks = 0;
2575 	error = kthread_create(g_mirror_worker, sc, &sc->sc_worker, 0, 0,
2576 	    "g_mirror %s", md->md_name);
2577 	if (error != 0) {
2578 		G_MIRROR_DEBUG(1, "Cannot create kernel thread for %s.",
2579 		    sc->sc_name);
2580 		g_destroy_geom(sc->sc_sync.ds_geom);
2581 		mtx_destroy(&sc->sc_events_mtx);
2582 		mtx_destroy(&sc->sc_queue_mtx);
2583 		g_destroy_geom(sc->sc_geom);
2584 		free(sc, M_MIRROR);
2585 		return (NULL);
2586 	}
2587 
2588 	G_MIRROR_DEBUG(0, "Device %s created (id=%u).", sc->sc_name, sc->sc_id);
2589 
2590 	sc->sc_rootmount = root_mount_hold("GMIRROR");
2591 	G_MIRROR_DEBUG(1, "root_mount_hold %p", sc->sc_rootmount);
2592 	/*
2593 	 * Run timeout.
2594 	 */
2595 	timeout = g_mirror_timeout * hz;
2596 	callout_reset(&sc->sc_callout, timeout, g_mirror_go, sc);
2597 	return (sc->sc_geom);
2598 }
2599 
2600 int
2601 g_mirror_destroy(struct g_mirror_softc *sc, boolean_t force)
2602 {
2603 	struct g_provider *pp;
2604 
2605 	g_topology_assert();
2606 
2607 	if (sc == NULL)
2608 		return (ENXIO);
2609 	pp = sc->sc_provider;
2610 	if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
2611 		if (force) {
2612 			G_MIRROR_DEBUG(1, "Device %s is still open, so it "
2613 			    "can't be definitely removed.", pp->name);
2614 		} else {
2615 			G_MIRROR_DEBUG(1,
2616 			    "Device %s is still open (r%dw%de%d).", pp->name,
2617 			    pp->acr, pp->acw, pp->ace);
2618 			return (EBUSY);
2619 		}
2620 	}
2621 
2622 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2623 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_WAIT;
2624 	g_topology_unlock();
2625 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
2626 	mtx_lock(&sc->sc_queue_mtx);
2627 	wakeup(sc);
2628 	mtx_unlock(&sc->sc_queue_mtx);
2629 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, &sc->sc_worker);
2630 	while (sc->sc_worker != NULL)
2631 		tsleep(&sc->sc_worker, PRIBIO, "m:destroy", hz / 5);
2632 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, &sc->sc_worker);
2633 	g_topology_lock();
2634 	g_mirror_destroy_device(sc);
2635 	free(sc, M_MIRROR);
2636 	return (0);
2637 }
2638 
2639 static void
2640 g_mirror_taste_orphan(struct g_consumer *cp)
2641 {
2642 
2643 	KASSERT(1 == 0, ("%s called while tasting %s.", __func__,
2644 	    cp->provider->name));
2645 }
2646 
2647 static struct g_geom *
2648 g_mirror_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
2649 {
2650 	struct g_mirror_metadata md;
2651 	struct g_mirror_softc *sc;
2652 	struct g_consumer *cp;
2653 	struct g_geom *gp;
2654 	int error;
2655 
2656 	g_topology_assert();
2657 	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
2658 	G_MIRROR_DEBUG(2, "Tasting %s.", pp->name);
2659 
2660 	gp = g_new_geomf(mp, "mirror:taste");
2661 	/*
2662 	 * This orphan function should be never called.
2663 	 */
2664 	gp->orphan = g_mirror_taste_orphan;
2665 	cp = g_new_consumer(gp);
2666 	g_attach(cp, pp);
2667 	error = g_mirror_read_metadata(cp, &md);
2668 	g_detach(cp);
2669 	g_destroy_consumer(cp);
2670 	g_destroy_geom(gp);
2671 	if (error != 0)
2672 		return (NULL);
2673 	gp = NULL;
2674 
2675 	if (md.md_provider[0] != '\0' && strcmp(md.md_provider, pp->name) != 0)
2676 		return (NULL);
2677 	if (md.md_provsize != 0 && md.md_provsize != pp->mediasize)
2678 		return (NULL);
2679 	if ((md.md_dflags & G_MIRROR_DISK_FLAG_INACTIVE) != 0) {
2680 		G_MIRROR_DEBUG(0,
2681 		    "Device %s: provider %s marked as inactive, skipping.",
2682 		    md.md_name, pp->name);
2683 		return (NULL);
2684 	}
2685 	if (g_mirror_debug >= 2)
2686 		mirror_metadata_dump(&md);
2687 
2688 	/*
2689 	 * Let's check if device already exists.
2690 	 */
2691 	sc = NULL;
2692 	LIST_FOREACH(gp, &mp->geom, geom) {
2693 		sc = gp->softc;
2694 		if (sc == NULL)
2695 			continue;
2696 		if (sc->sc_sync.ds_geom == gp)
2697 			continue;
2698 		if (strcmp(md.md_name, sc->sc_name) != 0)
2699 			continue;
2700 		if (md.md_mid != sc->sc_id) {
2701 			G_MIRROR_DEBUG(0, "Device %s already configured.",
2702 			    sc->sc_name);
2703 			return (NULL);
2704 		}
2705 		break;
2706 	}
2707 	if (gp == NULL) {
2708 		gp = g_mirror_create(mp, &md);
2709 		if (gp == NULL) {
2710 			G_MIRROR_DEBUG(0, "Cannot create device %s.",
2711 			    md.md_name);
2712 			return (NULL);
2713 		}
2714 		sc = gp->softc;
2715 	}
2716 	G_MIRROR_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
2717 	error = g_mirror_add_disk(sc, pp, &md);
2718 	if (error != 0) {
2719 		G_MIRROR_DEBUG(0, "Cannot add disk %s to %s (error=%d).",
2720 		    pp->name, gp->name, error);
2721 		if (LIST_EMPTY(&sc->sc_disks))
2722 			g_mirror_destroy(sc, 1);
2723 		return (NULL);
2724 	}
2725 	return (gp);
2726 }
2727 
2728 static int
2729 g_mirror_destroy_geom(struct gctl_req *req __unused,
2730     struct g_class *mp __unused, struct g_geom *gp)
2731 {
2732 
2733 	return (g_mirror_destroy(gp->softc, 0));
2734 }
2735 
2736 static void
2737 g_mirror_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
2738     struct g_consumer *cp, struct g_provider *pp)
2739 {
2740 	struct g_mirror_softc *sc;
2741 
2742 	g_topology_assert();
2743 
2744 	sc = gp->softc;
2745 	if (sc == NULL)
2746 		return;
2747 	/* Skip synchronization geom. */
2748 	if (gp == sc->sc_sync.ds_geom)
2749 		return;
2750 	if (pp != NULL) {
2751 		/* Nothing here. */
2752 	} else if (cp != NULL) {
2753 		struct g_mirror_disk *disk;
2754 
2755 		disk = cp->private;
2756 		if (disk == NULL)
2757 			return;
2758 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)disk->d_id);
2759 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2760 			sbuf_printf(sb, "%s<Synchronized>", indent);
2761 			if (disk->d_sync.ds_offset_done == 0)
2762 				sbuf_printf(sb, "0%%");
2763 			else {
2764 				sbuf_printf(sb, "%u%%",
2765 				    (u_int)((disk->d_sync.ds_offset_done * 100) /
2766 				    sc->sc_provider->mediasize));
2767 			}
2768 			sbuf_printf(sb, "</Synchronized>\n");
2769 		}
2770 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent,
2771 		    disk->d_sync.ds_syncid);
2772 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent,
2773 		    disk->d_genid);
2774 		sbuf_printf(sb, "%s<Flags>", indent);
2775 		if (disk->d_flags == 0)
2776 			sbuf_printf(sb, "NONE");
2777 		else {
2778 			int first = 1;
2779 
2780 #define	ADD_FLAG(flag, name)	do {					\
2781 	if ((disk->d_flags & (flag)) != 0) {				\
2782 		if (!first)						\
2783 			sbuf_printf(sb, ", ");				\
2784 		else							\
2785 			first = 0;					\
2786 		sbuf_printf(sb, name);					\
2787 	}								\
2788 } while (0)
2789 			ADD_FLAG(G_MIRROR_DISK_FLAG_DIRTY, "DIRTY");
2790 			ADD_FLAG(G_MIRROR_DISK_FLAG_HARDCODED, "HARDCODED");
2791 			ADD_FLAG(G_MIRROR_DISK_FLAG_INACTIVE, "INACTIVE");
2792 			ADD_FLAG(G_MIRROR_DISK_FLAG_SYNCHRONIZING,
2793 			    "SYNCHRONIZING");
2794 			ADD_FLAG(G_MIRROR_DISK_FLAG_FORCE_SYNC, "FORCE_SYNC");
2795 #undef	ADD_FLAG
2796 		}
2797 		sbuf_printf(sb, "</Flags>\n");
2798 		sbuf_printf(sb, "%s<Priority>%u</Priority>\n", indent,
2799 		    disk->d_priority);
2800 		sbuf_printf(sb, "%s<State>%s</State>\n", indent,
2801 		    g_mirror_disk_state2str(disk->d_state));
2802 	} else {
2803 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)sc->sc_id);
2804 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent, sc->sc_syncid);
2805 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent, sc->sc_genid);
2806 		sbuf_printf(sb, "%s<Flags>", indent);
2807 		if (sc->sc_flags == 0)
2808 			sbuf_printf(sb, "NONE");
2809 		else {
2810 			int first = 1;
2811 
2812 #define	ADD_FLAG(flag, name)	do {					\
2813 	if ((sc->sc_flags & (flag)) != 0) {				\
2814 		if (!first)						\
2815 			sbuf_printf(sb, ", ");				\
2816 		else							\
2817 			first = 0;					\
2818 		sbuf_printf(sb, name);					\
2819 	}								\
2820 } while (0)
2821 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOAUTOSYNC, "NOAUTOSYNC");
2822 #undef	ADD_FLAG
2823 		}
2824 		sbuf_printf(sb, "</Flags>\n");
2825 		sbuf_printf(sb, "%s<Slice>%u</Slice>\n", indent,
2826 		    (u_int)sc->sc_slice);
2827 		sbuf_printf(sb, "%s<Balance>%s</Balance>\n", indent,
2828 		    balance_name(sc->sc_balance));
2829 		sbuf_printf(sb, "%s<Components>%u</Components>\n", indent,
2830 		    sc->sc_ndisks);
2831 		sbuf_printf(sb, "%s<State>", indent);
2832 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
2833 			sbuf_printf(sb, "%s", "STARTING");
2834 		else if (sc->sc_ndisks ==
2835 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE))
2836 			sbuf_printf(sb, "%s", "COMPLETE");
2837 		else
2838 			sbuf_printf(sb, "%s", "DEGRADED");
2839 		sbuf_printf(sb, "</State>\n");
2840 	}
2841 }
2842 
2843 static void
2844 g_mirror_shutdown(void *arg, int howto)
2845 {
2846 	struct g_class *mp;
2847 	struct g_geom *gp, *gp2;
2848 
2849 	mp = arg;
2850 	DROP_GIANT();
2851 	g_topology_lock();
2852 	LIST_FOREACH_SAFE(gp, &mp->geom, geom, gp2) {
2853 		if (gp->softc == NULL)
2854 			continue;
2855 		g_mirror_destroy(gp->softc, 1);
2856 	}
2857 	g_topology_unlock();
2858 	PICKUP_GIANT();
2859 #if 0
2860 	tsleep(&gp, PRIBIO, "m:shutdown", hz * 20);
2861 #endif
2862 }
2863 
2864 static void
2865 g_mirror_init(struct g_class *mp)
2866 {
2867 
2868 	g_mirror_ehtag = EVENTHANDLER_REGISTER(shutdown_post_sync,
2869 	    g_mirror_shutdown, mp, SHUTDOWN_PRI_FIRST);
2870 	if (g_mirror_ehtag == NULL)
2871 		G_MIRROR_DEBUG(0, "Warning! Cannot register shutdown event.");
2872 }
2873 
2874 static void
2875 g_mirror_fini(struct g_class *mp)
2876 {
2877 
2878 	if (g_mirror_ehtag == NULL)
2879 		return;
2880 	EVENTHANDLER_DEREGISTER(shutdown_post_sync, g_mirror_ehtag);
2881 }
2882 
2883 DECLARE_GEOM_CLASS(g_mirror_class, g_mirror);
2884