xref: /freebsd/sys/geom/mirror/g_mirror.c (revision 6af83ee0d2941d18880b6aaa2b4facd1d30c6106)
1 /*-
2  * Copyright (c) 2004 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 	int error;
379 
380 	g_topology_assert();
381 	KASSERT(disk->d_consumer == NULL,
382 	    ("Disk already connected (device %s).", disk->d_softc->sc_name));
383 
384 	disk->d_consumer = g_new_consumer(disk->d_softc->sc_geom);
385 	disk->d_consumer->private = disk;
386 	disk->d_consumer->index = 0;
387 	error = g_attach(disk->d_consumer, pp);
388 	if (error != 0)
389 		return (error);
390 	error = g_access(disk->d_consumer, 1, 1, 1);
391 	if (error != 0) {
392 		G_MIRROR_DEBUG(0, "Cannot open consumer %s (error=%d).",
393 		    pp->name, error);
394 		return (error);
395 	}
396 
397 	G_MIRROR_DEBUG(2, "Disk %s connected.", g_mirror_get_diskname(disk));
398 	return (0);
399 }
400 
401 static void
402 g_mirror_disconnect_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
403 {
404 
405 	g_topology_assert();
406 
407 	if (cp == NULL)
408 		return;
409 	if (cp->provider != NULL)
410 		g_mirror_kill_consumer(sc, cp);
411 	else
412 		g_destroy_consumer(cp);
413 }
414 
415 /*
416  * Initialize disk. This means allocate memory, create consumer, attach it
417  * to the provider and open access (r1w1e1) to it.
418  */
419 static struct g_mirror_disk *
420 g_mirror_init_disk(struct g_mirror_softc *sc, struct g_provider *pp,
421     struct g_mirror_metadata *md, int *errorp)
422 {
423 	struct g_mirror_disk *disk;
424 	int error;
425 
426 	disk = malloc(sizeof(*disk), M_MIRROR, M_NOWAIT | M_ZERO);
427 	if (disk == NULL) {
428 		error = ENOMEM;
429 		goto fail;
430 	}
431 	disk->d_softc = sc;
432 	error = g_mirror_connect_disk(disk, pp);
433 	if (error != 0)
434 		goto fail;
435 	disk->d_id = md->md_did;
436 	disk->d_state = G_MIRROR_DISK_STATE_NONE;
437 	disk->d_priority = md->md_priority;
438 	disk->d_delay.sec = 0;
439 	disk->d_delay.frac = 0;
440 	binuptime(&disk->d_last_used);
441 	disk->d_flags = md->md_dflags;
442 	if (md->md_provider[0] != '\0')
443 		disk->d_flags |= G_MIRROR_DISK_FLAG_HARDCODED;
444 	disk->d_sync.ds_consumer = NULL;
445 	disk->d_sync.ds_offset = md->md_sync_offset;
446 	disk->d_sync.ds_offset_done = md->md_sync_offset;
447 	disk->d_sync.ds_resync = -1;
448 	disk->d_genid = md->md_genid;
449 	disk->d_sync.ds_syncid = md->md_syncid;
450 	if (errorp != NULL)
451 		*errorp = 0;
452 	return (disk);
453 fail:
454 	if (errorp != NULL)
455 		*errorp = error;
456 	if (disk != NULL) {
457 		g_mirror_disconnect_consumer(sc, disk->d_consumer);
458 		free(disk, M_MIRROR);
459 	}
460 	return (NULL);
461 }
462 
463 static void
464 g_mirror_destroy_disk(struct g_mirror_disk *disk)
465 {
466 	struct g_mirror_softc *sc;
467 
468 	g_topology_assert();
469 
470 	LIST_REMOVE(disk, d_next);
471 	g_mirror_event_cancel(disk);
472 	sc = disk->d_softc;
473 	if (sc->sc_hint == disk)
474 		sc->sc_hint = NULL;
475 	switch (disk->d_state) {
476 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
477 		g_mirror_sync_stop(disk, 1);
478 		/* FALLTHROUGH */
479 	case G_MIRROR_DISK_STATE_NEW:
480 	case G_MIRROR_DISK_STATE_STALE:
481 	case G_MIRROR_DISK_STATE_ACTIVE:
482 		g_mirror_disconnect_consumer(sc, disk->d_consumer);
483 		free(disk, M_MIRROR);
484 		break;
485 	default:
486 		KASSERT(0 == 1, ("Wrong disk state (%s, %s).",
487 		    g_mirror_get_diskname(disk),
488 		    g_mirror_disk_state2str(disk->d_state)));
489 	}
490 }
491 
492 static void
493 g_mirror_destroy_device(struct g_mirror_softc *sc)
494 {
495 	struct g_mirror_disk *disk;
496 	struct g_mirror_event *ep;
497 	struct g_geom *gp;
498 	struct g_consumer *cp, *tmpcp;
499 
500 	g_topology_assert();
501 
502 	gp = sc->sc_geom;
503 	if (sc->sc_provider != NULL)
504 		g_mirror_destroy_provider(sc);
505 	for (disk = LIST_FIRST(&sc->sc_disks); disk != NULL;
506 	    disk = LIST_FIRST(&sc->sc_disks)) {
507 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
508 		g_mirror_update_metadata(disk);
509 		g_mirror_destroy_disk(disk);
510 	}
511 	while ((ep = g_mirror_event_get(sc)) != NULL) {
512 		g_mirror_event_remove(sc, ep);
513 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
514 			g_mirror_event_free(ep);
515 		else {
516 			ep->e_error = ECANCELED;
517 			ep->e_flags |= G_MIRROR_EVENT_DONE;
518 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, ep);
519 			mtx_lock(&sc->sc_events_mtx);
520 			wakeup(ep);
521 			mtx_unlock(&sc->sc_events_mtx);
522 		}
523 	}
524 	callout_drain(&sc->sc_callout);
525 	gp->softc = NULL;
526 
527 	LIST_FOREACH_SAFE(cp, &sc->sc_sync.ds_geom->consumer, consumer, tmpcp) {
528 		g_mirror_disconnect_consumer(sc, cp);
529 	}
530 	sc->sc_sync.ds_geom->softc = NULL;
531 	g_wither_geom(sc->sc_sync.ds_geom, ENXIO);
532 	mtx_destroy(&sc->sc_queue_mtx);
533 	mtx_destroy(&sc->sc_events_mtx);
534 	G_MIRROR_DEBUG(0, "Device %s destroyed.", gp->name);
535 	g_wither_geom(gp, ENXIO);
536 }
537 
538 static void
539 g_mirror_orphan(struct g_consumer *cp)
540 {
541 	struct g_mirror_disk *disk;
542 
543 	g_topology_assert();
544 
545 	disk = cp->private;
546 	if (disk == NULL)
547 		return;
548 	disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
549 	g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
550 	    G_MIRROR_EVENT_DONTWAIT);
551 }
552 
553 /*
554  * Function should return the next active disk on the list.
555  * It is possible that it will be the same disk as given.
556  * If there are no active disks on list, NULL is returned.
557  */
558 static __inline struct g_mirror_disk *
559 g_mirror_find_next(struct g_mirror_softc *sc, struct g_mirror_disk *disk)
560 {
561 	struct g_mirror_disk *dp;
562 
563 	for (dp = LIST_NEXT(disk, d_next); dp != disk;
564 	    dp = LIST_NEXT(dp, d_next)) {
565 		if (dp == NULL)
566 			dp = LIST_FIRST(&sc->sc_disks);
567 		if (dp->d_state == G_MIRROR_DISK_STATE_ACTIVE)
568 			break;
569 	}
570 	if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
571 		return (NULL);
572 	return (dp);
573 }
574 
575 static struct g_mirror_disk *
576 g_mirror_get_disk(struct g_mirror_softc *sc)
577 {
578 	struct g_mirror_disk *disk;
579 
580 	if (sc->sc_hint == NULL) {
581 		sc->sc_hint = LIST_FIRST(&sc->sc_disks);
582 		if (sc->sc_hint == NULL)
583 			return (NULL);
584 	}
585 	disk = sc->sc_hint;
586 	if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE) {
587 		disk = g_mirror_find_next(sc, disk);
588 		if (disk == NULL)
589 			return (NULL);
590 	}
591 	sc->sc_hint = g_mirror_find_next(sc, disk);
592 	return (disk);
593 }
594 
595 static int
596 g_mirror_write_metadata(struct g_mirror_disk *disk,
597     struct g_mirror_metadata *md)
598 {
599 	struct g_mirror_softc *sc;
600 	struct g_consumer *cp;
601 	off_t offset, length;
602 	u_char *sector;
603 	int error = 0;
604 
605 	g_topology_assert();
606 
607 	sc = disk->d_softc;
608 	cp = disk->d_consumer;
609 	KASSERT(cp != NULL, ("NULL consumer (%s).", sc->sc_name));
610 	KASSERT(cp->provider != NULL, ("NULL provider (%s).", sc->sc_name));
611 	KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
612 	    ("Consumer %s closed? (r%dw%de%d).", cp->provider->name, cp->acr,
613 	    cp->acw, cp->ace));
614 	length = cp->provider->sectorsize;
615 	offset = cp->provider->mediasize - length;
616 	sector = malloc((size_t)length, M_MIRROR, M_WAITOK | M_ZERO);
617 	if (md != NULL)
618 		mirror_metadata_encode(md, sector);
619 	g_topology_unlock();
620 	error = g_write_data(cp, offset, sector, length);
621 	g_topology_lock();
622 	free(sector, M_MIRROR);
623 	if (error != 0) {
624 		disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_GENID;
625 		g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
626 		    G_MIRROR_EVENT_DONTWAIT);
627 	}
628 	return (error);
629 }
630 
631 static int
632 g_mirror_clear_metadata(struct g_mirror_disk *disk)
633 {
634 	int error;
635 
636 	g_topology_assert();
637 	error = g_mirror_write_metadata(disk, NULL);
638 	if (error == 0) {
639 		G_MIRROR_DEBUG(2, "Metadata on %s cleared.",
640 		    g_mirror_get_diskname(disk));
641 	} else {
642 		G_MIRROR_DEBUG(0,
643 		    "Cannot clear metadata on disk %s (error=%d).",
644 		    g_mirror_get_diskname(disk), error);
645 	}
646 	return (error);
647 }
648 
649 void
650 g_mirror_fill_metadata(struct g_mirror_softc *sc, struct g_mirror_disk *disk,
651     struct g_mirror_metadata *md)
652 {
653 
654 	strlcpy(md->md_magic, G_MIRROR_MAGIC, sizeof(md->md_magic));
655 	md->md_version = G_MIRROR_VERSION;
656 	strlcpy(md->md_name, sc->sc_name, sizeof(md->md_name));
657 	md->md_mid = sc->sc_id;
658 	md->md_all = sc->sc_ndisks;
659 	md->md_slice = sc->sc_slice;
660 	md->md_balance = sc->sc_balance;
661 	md->md_genid = sc->sc_genid;
662 	md->md_mediasize = sc->sc_mediasize;
663 	md->md_sectorsize = sc->sc_sectorsize;
664 	md->md_mflags = (sc->sc_flags & G_MIRROR_DEVICE_FLAG_MASK);
665 	bzero(md->md_provider, sizeof(md->md_provider));
666 	if (disk == NULL) {
667 		md->md_did = arc4random();
668 		md->md_priority = 0;
669 		md->md_syncid = 0;
670 		md->md_dflags = 0;
671 		md->md_sync_offset = 0;
672 	} else {
673 		md->md_did = disk->d_id;
674 		md->md_priority = disk->d_priority;
675 		md->md_syncid = disk->d_sync.ds_syncid;
676 		md->md_dflags = (disk->d_flags & G_MIRROR_DISK_FLAG_MASK);
677 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
678 			md->md_sync_offset = disk->d_sync.ds_offset_done;
679 		else
680 			md->md_sync_offset = 0;
681 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_HARDCODED) != 0) {
682 			strlcpy(md->md_provider,
683 			    disk->d_consumer->provider->name,
684 			    sizeof(md->md_provider));
685 		}
686 	}
687 }
688 
689 void
690 g_mirror_update_metadata(struct g_mirror_disk *disk)
691 {
692 	struct g_mirror_metadata md;
693 	int error;
694 
695 	g_topology_assert();
696 	g_mirror_fill_metadata(disk->d_softc, disk, &md);
697 	error = g_mirror_write_metadata(disk, &md);
698 	if (error == 0) {
699 		G_MIRROR_DEBUG(2, "Metadata on %s updated.",
700 		    g_mirror_get_diskname(disk));
701 	} else {
702 		G_MIRROR_DEBUG(0,
703 		    "Cannot update metadata on disk %s (error=%d).",
704 		    g_mirror_get_diskname(disk), error);
705 	}
706 }
707 
708 static void
709 g_mirror_bump_syncid(struct g_mirror_softc *sc)
710 {
711 	struct g_mirror_disk *disk;
712 
713 	g_topology_assert();
714 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
715 	    ("%s called with no active disks (device=%s).", __func__,
716 	    sc->sc_name));
717 
718 	sc->sc_syncid++;
719 	G_MIRROR_DEBUG(1, "Device %s: syncid bumped to %u.", sc->sc_name,
720 	    sc->sc_syncid);
721 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
722 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
723 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
724 			disk->d_sync.ds_syncid = sc->sc_syncid;
725 			g_mirror_update_metadata(disk);
726 		}
727 	}
728 }
729 
730 static void
731 g_mirror_bump_genid(struct g_mirror_softc *sc)
732 {
733 	struct g_mirror_disk *disk;
734 
735 	g_topology_assert();
736 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
737 	    ("%s called with no active disks (device=%s).", __func__,
738 	    sc->sc_name));
739 
740 	sc->sc_genid++;
741 	G_MIRROR_DEBUG(1, "Device %s: genid bumped to %u.", sc->sc_name,
742 	    sc->sc_genid);
743 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
744 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
745 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
746 			disk->d_genid = sc->sc_genid;
747 			g_mirror_update_metadata(disk);
748 		}
749 	}
750 }
751 
752 static void
753 g_mirror_idle(struct g_mirror_softc *sc)
754 {
755 	struct g_mirror_disk *disk;
756 
757 	if (sc->sc_provider == NULL || sc->sc_provider->acw == 0)
758 		return;
759 	sc->sc_idle = 1;
760 	g_topology_lock();
761 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
762 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
763 			continue;
764 		G_MIRROR_DEBUG(1, "Disk %s (device %s) marked as clean.",
765 		    g_mirror_get_diskname(disk), sc->sc_name);
766 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
767 		g_mirror_update_metadata(disk);
768 	}
769 	g_topology_unlock();
770 }
771 
772 static void
773 g_mirror_unidle(struct g_mirror_softc *sc)
774 {
775 	struct g_mirror_disk *disk;
776 
777 	sc->sc_idle = 0;
778 	g_topology_lock();
779 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
780 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
781 			continue;
782 		G_MIRROR_DEBUG(1, "Disk %s (device %s) marked as dirty.",
783 		    g_mirror_get_diskname(disk), sc->sc_name);
784 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
785 		g_mirror_update_metadata(disk);
786 	}
787 	g_topology_unlock();
788 }
789 
790 /*
791  * Return 1 if we should check if mirror is idling.
792  */
793 static int
794 g_mirror_check_idle(struct g_mirror_softc *sc)
795 {
796 	struct g_mirror_disk *disk;
797 
798 	if (sc->sc_idle)
799 		return (0);
800 	if (sc->sc_provider != NULL && sc->sc_provider->acw == 0)
801 		return (0);
802 	/*
803 	 * Check if there are no in-flight requests.
804 	 */
805 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
806 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
807 			continue;
808 		if (disk->d_consumer->index > 0)
809 			return (0);
810 	}
811 	return (1);
812 }
813 
814 static __inline int
815 bintime_cmp(struct bintime *bt1, struct bintime *bt2)
816 {
817 
818 	if (bt1->sec < bt2->sec)
819 		return (-1);
820 	else if (bt1->sec > bt2->sec)
821 		return (1);
822 	if (bt1->frac < bt2->frac)
823 		return (-1);
824 	else if (bt1->frac > bt2->frac)
825 		return (1);
826 	return (0);
827 }
828 
829 static void
830 g_mirror_update_delay(struct g_mirror_disk *disk, struct bio *bp)
831 {
832 
833 	if (disk->d_softc->sc_balance != G_MIRROR_BALANCE_LOAD)
834 		return;
835 	binuptime(&disk->d_delay);
836 	bintime_sub(&disk->d_delay, &bp->bio_t0);
837 }
838 
839 static void
840 g_mirror_done(struct bio *bp)
841 {
842 	struct g_mirror_softc *sc;
843 
844 	sc = bp->bio_from->geom->softc;
845 	bp->bio_cflags |= G_MIRROR_BIO_FLAG_REGULAR;
846 	mtx_lock(&sc->sc_queue_mtx);
847 	bioq_disksort(&sc->sc_queue, bp);
848 	wakeup(sc);
849 	mtx_unlock(&sc->sc_queue_mtx);
850 }
851 
852 static void
853 g_mirror_regular_request(struct bio *bp)
854 {
855 	struct g_mirror_softc *sc;
856 	struct g_mirror_disk *disk;
857 	struct bio *pbp;
858 
859 	g_topology_assert_not();
860 
861 	bp->bio_from->index--;
862 	pbp = bp->bio_parent;
863 	sc = pbp->bio_to->geom->softc;
864 	disk = bp->bio_from->private;
865 	if (disk == NULL) {
866 		g_topology_lock();
867 		g_mirror_kill_consumer(sc, bp->bio_from);
868 		g_topology_unlock();
869 	} else {
870 		g_mirror_update_delay(disk, bp);
871 	}
872 
873 	pbp->bio_inbed++;
874 	KASSERT(pbp->bio_inbed <= pbp->bio_children,
875 	    ("bio_inbed (%u) is bigger than bio_children (%u).", pbp->bio_inbed,
876 	    pbp->bio_children));
877 	if (bp->bio_error == 0 && pbp->bio_error == 0) {
878 		G_MIRROR_LOGREQ(3, bp, "Request delivered.");
879 		g_destroy_bio(bp);
880 		if (pbp->bio_children == pbp->bio_inbed) {
881 			G_MIRROR_LOGREQ(3, pbp, "Request delivered.");
882 			pbp->bio_completed = pbp->bio_length;
883 			g_io_deliver(pbp, pbp->bio_error);
884 		}
885 		return;
886 	} else if (bp->bio_error != 0) {
887 		if (pbp->bio_error == 0)
888 			pbp->bio_error = bp->bio_error;
889 		G_MIRROR_LOGREQ(0, bp, "Request failed (error=%d).",
890 		    bp->bio_error);
891 		if (disk != NULL) {
892 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
893 			g_mirror_event_send(disk,
894 			    G_MIRROR_DISK_STATE_DISCONNECTED,
895 			    G_MIRROR_EVENT_DONTWAIT);
896 		}
897 		switch (pbp->bio_cmd) {
898 		case BIO_DELETE:
899 		case BIO_WRITE:
900 			pbp->bio_inbed--;
901 			pbp->bio_children--;
902 			break;
903 		}
904 	}
905 	g_destroy_bio(bp);
906 
907 	switch (pbp->bio_cmd) {
908 	case BIO_READ:
909 		if (pbp->bio_children == pbp->bio_inbed) {
910 			pbp->bio_error = 0;
911 			mtx_lock(&sc->sc_queue_mtx);
912 			bioq_disksort(&sc->sc_queue, pbp);
913 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
914 			wakeup(sc);
915 			mtx_unlock(&sc->sc_queue_mtx);
916 		}
917 		break;
918 	case BIO_DELETE:
919 	case BIO_WRITE:
920 		if (pbp->bio_children == 0) {
921 			/*
922 			 * All requests failed.
923 			 */
924 		} else if (pbp->bio_inbed < pbp->bio_children) {
925 			/* Do nothing. */
926 			break;
927 		} else if (pbp->bio_children == pbp->bio_inbed) {
928 			/* Some requests succeeded. */
929 			pbp->bio_error = 0;
930 			pbp->bio_completed = pbp->bio_length;
931 		}
932 		g_io_deliver(pbp, pbp->bio_error);
933 		break;
934 	default:
935 		KASSERT(1 == 0, ("Invalid request: %u.", pbp->bio_cmd));
936 		break;
937 	}
938 }
939 
940 static void
941 g_mirror_sync_done(struct bio *bp)
942 {
943 	struct g_mirror_softc *sc;
944 
945 	G_MIRROR_LOGREQ(3, bp, "Synchronization request delivered.");
946 	sc = bp->bio_from->geom->softc;
947 	bp->bio_cflags |= G_MIRROR_BIO_FLAG_SYNC;
948 	mtx_lock(&sc->sc_queue_mtx);
949 	bioq_disksort(&sc->sc_queue, bp);
950 	wakeup(sc);
951 	mtx_unlock(&sc->sc_queue_mtx);
952 }
953 
954 static void
955 g_mirror_start(struct bio *bp)
956 {
957 	struct g_mirror_softc *sc;
958 
959 	sc = bp->bio_to->geom->softc;
960 	/*
961 	 * If sc == NULL or there are no valid disks, provider's error
962 	 * should be set and g_mirror_start() should not be called at all.
963 	 */
964 	KASSERT(sc != NULL && sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
965 	    ("Provider's error should be set (error=%d)(mirror=%s).",
966 	    bp->bio_to->error, bp->bio_to->name));
967 	G_MIRROR_LOGREQ(3, bp, "Request received.");
968 
969 	switch (bp->bio_cmd) {
970 	case BIO_READ:
971 	case BIO_WRITE:
972 	case BIO_DELETE:
973 		break;
974 	case BIO_GETATTR:
975 	default:
976 		g_io_deliver(bp, EOPNOTSUPP);
977 		return;
978 	}
979 	mtx_lock(&sc->sc_queue_mtx);
980 	bioq_disksort(&sc->sc_queue, bp);
981 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
982 	wakeup(sc);
983 	mtx_unlock(&sc->sc_queue_mtx);
984 }
985 
986 /*
987  * Send one synchronization request.
988  */
989 static void
990 g_mirror_sync_one(struct g_mirror_disk *disk)
991 {
992 	struct g_mirror_softc *sc;
993 	struct bio *bp;
994 
995 	sc = disk->d_softc;
996 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
997 	    ("Disk %s is not marked for synchronization.",
998 	    g_mirror_get_diskname(disk)));
999 
1000 	bp = g_new_bio();
1001 	if (bp == NULL)
1002 		return;
1003 	bp->bio_parent = NULL;
1004 	bp->bio_cmd = BIO_READ;
1005 	bp->bio_offset = disk->d_sync.ds_offset;
1006 	bp->bio_length = MIN(MAXPHYS, sc->sc_mediasize - bp->bio_offset);
1007 	bp->bio_cflags = 0;
1008 	bp->bio_done = g_mirror_sync_done;
1009 	bp->bio_data = disk->d_sync.ds_data;
1010 	if (bp->bio_data == NULL) {
1011 		g_destroy_bio(bp);
1012 		return;
1013 	}
1014 	disk->d_sync.ds_offset += bp->bio_length;
1015 	bp->bio_to = sc->sc_provider;
1016 	G_MIRROR_LOGREQ(3, bp, "Sending synchronization request.");
1017 	disk->d_sync.ds_consumer->index++;
1018 	g_io_request(bp, disk->d_sync.ds_consumer);
1019 }
1020 
1021 static void
1022 g_mirror_sync_request(struct bio *bp)
1023 {
1024 	struct g_mirror_softc *sc;
1025 	struct g_mirror_disk *disk;
1026 
1027 	bp->bio_from->index--;
1028 	sc = bp->bio_from->geom->softc;
1029 	disk = bp->bio_from->private;
1030 	if (disk == NULL) {
1031 		g_topology_lock();
1032 		g_mirror_kill_consumer(sc, bp->bio_from);
1033 		g_topology_unlock();
1034 		g_destroy_bio(bp);
1035 		return;
1036 	}
1037 
1038 	/*
1039 	 * Synchronization request.
1040 	 */
1041 	switch (bp->bio_cmd) {
1042 	case BIO_READ:
1043 	    {
1044 		struct g_consumer *cp;
1045 
1046 		if (bp->bio_error != 0) {
1047 			G_MIRROR_LOGREQ(0, bp,
1048 			    "Synchronization request failed (error=%d).",
1049 			    bp->bio_error);
1050 			g_destroy_bio(bp);
1051 			return;
1052 		}
1053 		G_MIRROR_LOGREQ(3, bp,
1054 		    "Synchronization request half-finished.");
1055 		bp->bio_cmd = BIO_WRITE;
1056 		bp->bio_cflags = 0;
1057 		cp = disk->d_consumer;
1058 		KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1059 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1060 		    cp->acr, cp->acw, cp->ace));
1061 		cp->index++;
1062 		g_io_request(bp, cp);
1063 		return;
1064 	    }
1065 	case BIO_WRITE:
1066 	    {
1067 		struct g_mirror_disk_sync *sync;
1068 
1069 		if (bp->bio_error != 0) {
1070 			G_MIRROR_LOGREQ(0, bp,
1071 			    "Synchronization request failed (error=%d).",
1072 			    bp->bio_error);
1073 			g_destroy_bio(bp);
1074 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
1075 			g_mirror_event_send(disk,
1076 			    G_MIRROR_DISK_STATE_DISCONNECTED,
1077 			    G_MIRROR_EVENT_DONTWAIT);
1078 			return;
1079 		}
1080 		G_MIRROR_LOGREQ(3, bp, "Synchronization request finished.");
1081 		sync = &disk->d_sync;
1082 		sync->ds_offset_done = bp->bio_offset + bp->bio_length;
1083 		g_destroy_bio(bp);
1084 		if (sync->ds_resync != -1)
1085 			break;
1086 		if (sync->ds_offset_done == sc->sc_provider->mediasize) {
1087 			/*
1088 			 * Disk up-to-date, activate it.
1089 			 */
1090 			g_mirror_event_send(disk, G_MIRROR_DISK_STATE_ACTIVE,
1091 			    G_MIRROR_EVENT_DONTWAIT);
1092 			return;
1093 		} else if (sync->ds_offset_done % (MAXPHYS * 100) == 0) {
1094 			/*
1095 			 * Update offset_done on every 100 blocks.
1096 			 * XXX: This should be configurable.
1097 			 */
1098 			g_topology_lock();
1099 			g_mirror_update_metadata(disk);
1100 			g_topology_unlock();
1101 		}
1102 		return;
1103 	    }
1104 	default:
1105 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1106 		    bp->bio_cmd, sc->sc_name));
1107 		break;
1108 	}
1109 }
1110 
1111 static void
1112 g_mirror_request_prefer(struct g_mirror_softc *sc, struct bio *bp)
1113 {
1114 	struct g_mirror_disk *disk;
1115 	struct g_consumer *cp;
1116 	struct bio *cbp;
1117 
1118 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1119 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE)
1120 			break;
1121 	}
1122 	if (disk == NULL) {
1123 		if (bp->bio_error == 0)
1124 			bp->bio_error = ENXIO;
1125 		g_io_deliver(bp, bp->bio_error);
1126 		return;
1127 	}
1128 	cbp = g_clone_bio(bp);
1129 	if (cbp == NULL) {
1130 		if (bp->bio_error == 0)
1131 			bp->bio_error = ENOMEM;
1132 		g_io_deliver(bp, bp->bio_error);
1133 		return;
1134 	}
1135 	/*
1136 	 * Fill in the component buf structure.
1137 	 */
1138 	cp = disk->d_consumer;
1139 	cbp->bio_done = g_mirror_done;
1140 	cbp->bio_to = cp->provider;
1141 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1142 	KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1143 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1144 	    cp->acw, cp->ace));
1145 	cp->index++;
1146 	g_io_request(cbp, cp);
1147 }
1148 
1149 static void
1150 g_mirror_request_round_robin(struct g_mirror_softc *sc, struct bio *bp)
1151 {
1152 	struct g_mirror_disk *disk;
1153 	struct g_consumer *cp;
1154 	struct bio *cbp;
1155 
1156 	disk = g_mirror_get_disk(sc);
1157 	if (disk == NULL) {
1158 		if (bp->bio_error == 0)
1159 			bp->bio_error = ENXIO;
1160 		g_io_deliver(bp, bp->bio_error);
1161 		return;
1162 	}
1163 	cbp = g_clone_bio(bp);
1164 	if (cbp == NULL) {
1165 		if (bp->bio_error == 0)
1166 			bp->bio_error = ENOMEM;
1167 		g_io_deliver(bp, bp->bio_error);
1168 		return;
1169 	}
1170 	/*
1171 	 * Fill in the component buf structure.
1172 	 */
1173 	cp = disk->d_consumer;
1174 	cbp->bio_done = g_mirror_done;
1175 	cbp->bio_to = cp->provider;
1176 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1177 	KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1178 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1179 	    cp->acw, cp->ace));
1180 	cp->index++;
1181 	g_io_request(cbp, cp);
1182 }
1183 
1184 static void
1185 g_mirror_request_load(struct g_mirror_softc *sc, struct bio *bp)
1186 {
1187 	struct g_mirror_disk *disk, *dp;
1188 	struct g_consumer *cp;
1189 	struct bio *cbp;
1190 	struct bintime curtime;
1191 
1192 	binuptime(&curtime);
1193 	/*
1194 	 * Find a disk which the smallest load.
1195 	 */
1196 	disk = NULL;
1197 	LIST_FOREACH(dp, &sc->sc_disks, d_next) {
1198 		if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1199 			continue;
1200 		/* If disk wasn't used for more than 2 sec, use it. */
1201 		if (curtime.sec - dp->d_last_used.sec >= 2) {
1202 			disk = dp;
1203 			break;
1204 		}
1205 		if (disk == NULL ||
1206 		    bintime_cmp(&dp->d_delay, &disk->d_delay) < 0) {
1207 			disk = dp;
1208 		}
1209 	}
1210 	cbp = g_clone_bio(bp);
1211 	if (cbp == NULL) {
1212 		if (bp->bio_error == 0)
1213 			bp->bio_error = ENOMEM;
1214 		g_io_deliver(bp, bp->bio_error);
1215 		return;
1216 	}
1217 	/*
1218 	 * Fill in the component buf structure.
1219 	 */
1220 	cp = disk->d_consumer;
1221 	cbp->bio_done = g_mirror_done;
1222 	cbp->bio_to = cp->provider;
1223 	binuptime(&disk->d_last_used);
1224 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1225 	KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1226 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1227 	    cp->acw, cp->ace));
1228 	cp->index++;
1229 	g_io_request(cbp, cp);
1230 }
1231 
1232 static void
1233 g_mirror_request_split(struct g_mirror_softc *sc, struct bio *bp)
1234 {
1235 	struct bio_queue_head queue;
1236 	struct g_mirror_disk *disk;
1237 	struct g_consumer *cp;
1238 	struct bio *cbp;
1239 	off_t left, mod, offset, slice;
1240 	u_char *data;
1241 	u_int ndisks;
1242 
1243 	if (bp->bio_length <= sc->sc_slice) {
1244 		g_mirror_request_round_robin(sc, bp);
1245 		return;
1246 	}
1247 	ndisks = g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE);
1248 	slice = bp->bio_length / ndisks;
1249 	mod = slice % sc->sc_provider->sectorsize;
1250 	if (mod != 0)
1251 		slice += sc->sc_provider->sectorsize - mod;
1252 	/*
1253 	 * Allocate all bios before sending any request, so we can
1254 	 * return ENOMEM in nice and clean way.
1255 	 */
1256 	left = bp->bio_length;
1257 	offset = bp->bio_offset;
1258 	data = bp->bio_data;
1259 	bioq_init(&queue);
1260 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1261 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1262 			continue;
1263 		cbp = g_clone_bio(bp);
1264 		if (cbp == NULL) {
1265 			for (cbp = bioq_first(&queue); cbp != NULL;
1266 			    cbp = bioq_first(&queue)) {
1267 				bioq_remove(&queue, cbp);
1268 				g_destroy_bio(cbp);
1269 			}
1270 			if (bp->bio_error == 0)
1271 				bp->bio_error = ENOMEM;
1272 			g_io_deliver(bp, bp->bio_error);
1273 			return;
1274 		}
1275 		bioq_insert_tail(&queue, cbp);
1276 		cbp->bio_done = g_mirror_done;
1277 		cbp->bio_caller1 = disk;
1278 		cbp->bio_to = disk->d_consumer->provider;
1279 		cbp->bio_offset = offset;
1280 		cbp->bio_data = data;
1281 		cbp->bio_length = MIN(left, slice);
1282 		left -= cbp->bio_length;
1283 		if (left == 0)
1284 			break;
1285 		offset += cbp->bio_length;
1286 		data += cbp->bio_length;
1287 	}
1288 	for (cbp = bioq_first(&queue); cbp != NULL; cbp = bioq_first(&queue)) {
1289 		bioq_remove(&queue, cbp);
1290 		G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1291 		disk = cbp->bio_caller1;
1292 		cbp->bio_caller1 = NULL;
1293 		cp = disk->d_consumer;
1294 		KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1295 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1296 		    cp->acr, cp->acw, cp->ace));
1297 		disk->d_consumer->index++;
1298 		g_io_request(cbp, disk->d_consumer);
1299 	}
1300 }
1301 
1302 static void
1303 g_mirror_register_request(struct bio *bp)
1304 {
1305 	struct g_mirror_softc *sc;
1306 
1307 	sc = bp->bio_to->geom->softc;
1308 	switch (bp->bio_cmd) {
1309 	case BIO_READ:
1310 		switch (sc->sc_balance) {
1311 		case G_MIRROR_BALANCE_LOAD:
1312 			g_mirror_request_load(sc, bp);
1313 			break;
1314 		case G_MIRROR_BALANCE_PREFER:
1315 			g_mirror_request_prefer(sc, bp);
1316 			break;
1317 		case G_MIRROR_BALANCE_ROUND_ROBIN:
1318 			g_mirror_request_round_robin(sc, bp);
1319 			break;
1320 		case G_MIRROR_BALANCE_SPLIT:
1321 			g_mirror_request_split(sc, bp);
1322 			break;
1323 		}
1324 		return;
1325 	case BIO_WRITE:
1326 	case BIO_DELETE:
1327 	    {
1328 		struct g_mirror_disk *disk;
1329 		struct g_mirror_disk_sync *sync;
1330 		struct bio_queue_head queue;
1331 		struct g_consumer *cp;
1332 		struct bio *cbp;
1333 
1334 		if (sc->sc_idle)
1335 			g_mirror_unidle(sc);
1336 		/*
1337 		 * Allocate all bios before sending any request, so we can
1338 		 * return ENOMEM in nice and clean way.
1339 		 */
1340 		bioq_init(&queue);
1341 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1342 			sync = &disk->d_sync;
1343 			switch (disk->d_state) {
1344 			case G_MIRROR_DISK_STATE_ACTIVE:
1345 				break;
1346 			case G_MIRROR_DISK_STATE_SYNCHRONIZING:
1347 				if (bp->bio_offset >= sync->ds_offset)
1348 					continue;
1349 				else if (bp->bio_offset + bp->bio_length >
1350 				    sync->ds_offset_done &&
1351 				    (bp->bio_offset < sync->ds_resync ||
1352 				     sync->ds_resync == -1)) {
1353 					sync->ds_resync = bp->bio_offset -
1354 					    (bp->bio_offset % MAXPHYS);
1355 				}
1356 				break;
1357 			default:
1358 				continue;
1359 			}
1360 			cbp = g_clone_bio(bp);
1361 			if (cbp == NULL) {
1362 				for (cbp = bioq_first(&queue); cbp != NULL;
1363 				    cbp = bioq_first(&queue)) {
1364 					bioq_remove(&queue, cbp);
1365 					g_destroy_bio(cbp);
1366 				}
1367 				if (bp->bio_error == 0)
1368 					bp->bio_error = ENOMEM;
1369 				g_io_deliver(bp, bp->bio_error);
1370 				return;
1371 			}
1372 			bioq_insert_tail(&queue, cbp);
1373 			cbp->bio_done = g_mirror_done;
1374 			cp = disk->d_consumer;
1375 			cbp->bio_caller1 = cp;
1376 			cbp->bio_to = cp->provider;
1377 			KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1378 			    ("Consumer %s not opened (r%dw%de%d).",
1379 			    cp->provider->name, cp->acr, cp->acw, cp->ace));
1380 		}
1381 		for (cbp = bioq_first(&queue); cbp != NULL;
1382 		    cbp = bioq_first(&queue)) {
1383 			bioq_remove(&queue, cbp);
1384 			G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1385 			cp = cbp->bio_caller1;
1386 			cbp->bio_caller1 = NULL;
1387 			cp->index++;
1388 			g_io_request(cbp, cp);
1389 		}
1390 		/*
1391 		 * Bump syncid on first write.
1392 		 */
1393 		if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0) {
1394 			sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
1395 			g_topology_lock();
1396 			g_mirror_bump_syncid(sc);
1397 			g_topology_unlock();
1398 		}
1399 		return;
1400 	    }
1401 	default:
1402 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1403 		    bp->bio_cmd, sc->sc_name));
1404 		break;
1405 	}
1406 }
1407 
1408 static int
1409 g_mirror_can_destroy(struct g_mirror_softc *sc)
1410 {
1411 	struct g_geom *gp;
1412 	struct g_consumer *cp;
1413 
1414 	g_topology_assert();
1415 	gp = sc->sc_geom;
1416 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1417 		if (g_mirror_is_busy(sc, cp))
1418 			return (0);
1419 	}
1420 	gp = sc->sc_sync.ds_geom;
1421 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1422 		if (g_mirror_is_busy(sc, cp))
1423 			return (0);
1424 	}
1425 	G_MIRROR_DEBUG(2, "No I/O requests for %s, it can be destroyed.",
1426 	    sc->sc_name);
1427 	return (1);
1428 }
1429 
1430 static int
1431 g_mirror_try_destroy(struct g_mirror_softc *sc)
1432 {
1433 
1434 	g_topology_lock();
1435 	if (!g_mirror_can_destroy(sc)) {
1436 		g_topology_unlock();
1437 		return (0);
1438 	}
1439 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_WAIT) != 0) {
1440 		g_topology_unlock();
1441 		G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1442 		    &sc->sc_worker);
1443 		wakeup(&sc->sc_worker);
1444 		sc->sc_worker = NULL;
1445 	} else {
1446 		g_mirror_destroy_device(sc);
1447 		g_topology_unlock();
1448 		free(sc, M_MIRROR);
1449 	}
1450 	return (1);
1451 }
1452 
1453 /*
1454  * Worker thread.
1455  */
1456 static void
1457 g_mirror_worker(void *arg)
1458 {
1459 	struct g_mirror_softc *sc;
1460 	struct g_mirror_disk *disk;
1461 	struct g_mirror_disk_sync *sync;
1462 	struct g_mirror_event *ep;
1463 	struct bio *bp;
1464 	u_int nreqs;
1465 
1466 	sc = arg;
1467 	mtx_lock_spin(&sched_lock);
1468 	sched_prio(curthread, PRIBIO);
1469 	mtx_unlock_spin(&sched_lock);
1470 
1471 	nreqs = 0;
1472 	for (;;) {
1473 		G_MIRROR_DEBUG(5, "%s: Let's see...", __func__);
1474 		/*
1475 		 * First take a look at events.
1476 		 * This is important to handle events before any I/O requests.
1477 		 */
1478 		ep = g_mirror_event_get(sc);
1479 		if (ep != NULL && g_topology_try_lock()) {
1480 			g_mirror_event_remove(sc, ep);
1481 			if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0) {
1482 				/* Update only device status. */
1483 				G_MIRROR_DEBUG(3,
1484 				    "Running event for device %s.",
1485 				    sc->sc_name);
1486 				ep->e_error = 0;
1487 				g_mirror_update_device(sc, 1);
1488 			} else {
1489 				/* Update disk status. */
1490 				G_MIRROR_DEBUG(3, "Running event for disk %s.",
1491 				     g_mirror_get_diskname(ep->e_disk));
1492 				ep->e_error = g_mirror_update_disk(ep->e_disk,
1493 				    ep->e_state);
1494 				if (ep->e_error == 0)
1495 					g_mirror_update_device(sc, 0);
1496 			}
1497 			g_topology_unlock();
1498 			if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0) {
1499 				KASSERT(ep->e_error == 0,
1500 				    ("Error cannot be handled."));
1501 				g_mirror_event_free(ep);
1502 			} else {
1503 				ep->e_flags |= G_MIRROR_EVENT_DONE;
1504 				G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1505 				    ep);
1506 				mtx_lock(&sc->sc_events_mtx);
1507 				wakeup(ep);
1508 				mtx_unlock(&sc->sc_events_mtx);
1509 			}
1510 			if ((sc->sc_flags &
1511 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1512 				if (g_mirror_try_destroy(sc))
1513 					kthread_exit(0);
1514 			}
1515 			G_MIRROR_DEBUG(5, "%s: I'm here 1.", __func__);
1516 			continue;
1517 		}
1518 		/*
1519 		 * Now I/O requests.
1520 		 */
1521 		/* Get first request from the queue. */
1522 		mtx_lock(&sc->sc_queue_mtx);
1523 		bp = bioq_first(&sc->sc_queue);
1524 		if (bp == NULL) {
1525 			if (ep != NULL) {
1526 				/*
1527 				 * No I/O requests and topology lock was
1528 				 * already held? Try again.
1529 				 */
1530 				mtx_unlock(&sc->sc_queue_mtx);
1531 				continue;
1532 			}
1533 			if ((sc->sc_flags &
1534 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1535 				mtx_unlock(&sc->sc_queue_mtx);
1536 				if (g_mirror_try_destroy(sc))
1537 					kthread_exit(0);
1538 				mtx_lock(&sc->sc_queue_mtx);
1539 			}
1540 		}
1541 		if (sc->sc_sync.ds_ndisks > 0 &&
1542 		    (bp == NULL || nreqs > g_mirror_reqs_per_sync)) {
1543 			mtx_unlock(&sc->sc_queue_mtx);
1544 			/*
1545 			 * It is time for synchronization...
1546 			 */
1547 			nreqs = 0;
1548 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1549 				if (disk->d_state !=
1550 				    G_MIRROR_DISK_STATE_SYNCHRONIZING) {
1551 					continue;
1552 				}
1553 				sync = &disk->d_sync;
1554 				if (sync->ds_offset >=
1555 				    sc->sc_provider->mediasize) {
1556 					continue;
1557 				}
1558 				if (sync->ds_offset > sync->ds_offset_done)
1559 					continue;
1560 				if (sync->ds_resync != -1) {
1561 					sync->ds_offset = sync->ds_resync;
1562 					sync->ds_offset_done = sync->ds_resync;
1563 					sync->ds_resync = -1;
1564 				}
1565 				g_mirror_sync_one(disk);
1566 			}
1567 			G_MIRROR_DEBUG(5, "%s: I'm here 2.", __func__);
1568 			goto sleep;
1569 		}
1570 		if (bp == NULL) {
1571 			if (g_mirror_check_idle(sc)) {
1572 				u_int idletime;
1573 
1574 				idletime = g_mirror_idletime;
1575 				if (idletime == 0)
1576 					idletime = 1;
1577 				idletime *= hz;
1578 				if (msleep(sc, &sc->sc_queue_mtx, PRIBIO | PDROP,
1579 				    "m:w1", idletime) == EWOULDBLOCK) {
1580 					G_MIRROR_DEBUG(5, "%s: I'm here 3.",
1581 					    __func__);
1582 					/*
1583 					 * No I/O requests in 'idletime' seconds,
1584 					 * so mark components as clean.
1585 					 */
1586 					g_mirror_idle(sc);
1587 				}
1588 				G_MIRROR_DEBUG(5, "%s: I'm here 4.", __func__);
1589 			} else {
1590 				MSLEEP(sc, &sc->sc_queue_mtx, PRIBIO | PDROP,
1591 				    "m:w2", 0);
1592 				G_MIRROR_DEBUG(5, "%s: I'm here 5.", __func__);
1593 			}
1594 			continue;
1595 		}
1596 		nreqs++;
1597 		bioq_remove(&sc->sc_queue, bp);
1598 		mtx_unlock(&sc->sc_queue_mtx);
1599 
1600 		if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_REGULAR) != 0) {
1601 			g_mirror_regular_request(bp);
1602 		} else if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0) {
1603 			u_int timeout, sps;
1604 
1605 			g_mirror_sync_request(bp);
1606 sleep:
1607 			sps = g_mirror_syncs_per_sec;
1608 			if (sps == 0) {
1609 				G_MIRROR_DEBUG(5, "%s: I'm here 6.", __func__);
1610 				continue;
1611 			}
1612 			if (ep != NULL) {
1613 				/*
1614 				 * We have some pending events, don't sleep now.
1615 				 */
1616 				G_MIRROR_DEBUG(5, "%s: I'm here 7.", __func__);
1617 				continue;
1618 			}
1619 			mtx_lock(&sc->sc_queue_mtx);
1620 			if (bioq_first(&sc->sc_queue) != NULL) {
1621 				mtx_unlock(&sc->sc_queue_mtx);
1622 				G_MIRROR_DEBUG(5, "%s: I'm here 8.", __func__);
1623 				continue;
1624 			}
1625 			timeout = hz / sps;
1626 			if (timeout == 0)
1627 				timeout = 1;
1628 			MSLEEP(sc, &sc->sc_queue_mtx, PRIBIO | PDROP, "m:w3",
1629 			    timeout);
1630 		} else {
1631 			g_mirror_register_request(bp);
1632 		}
1633 		G_MIRROR_DEBUG(5, "%s: I'm here 9.", __func__);
1634 	}
1635 }
1636 
1637 /*
1638  * Open disk's consumer if needed.
1639  */
1640 static void
1641 g_mirror_update_access(struct g_mirror_disk *disk)
1642 {
1643 	struct g_provider *pp;
1644 
1645 	g_topology_assert();
1646 
1647 	pp = disk->d_softc->sc_provider;
1648 	if (pp == NULL)
1649 		return;
1650 	if (pp->acw > 0) {
1651 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) == 0) {
1652 			G_MIRROR_DEBUG(1,
1653 			    "Disk %s (device %s) marked as dirty.",
1654 			    g_mirror_get_diskname(disk),
1655 			    disk->d_softc->sc_name);
1656 			disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1657 		}
1658 	} else if (pp->acw == 0) {
1659 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
1660 			G_MIRROR_DEBUG(1,
1661 			    "Disk %s (device %s) marked as clean.",
1662 			    g_mirror_get_diskname(disk),
1663 			    disk->d_softc->sc_name);
1664 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
1665 		}
1666 	}
1667 }
1668 
1669 static void
1670 g_mirror_sync_start(struct g_mirror_disk *disk)
1671 {
1672 	struct g_mirror_softc *sc;
1673 	int error;
1674 
1675 	g_topology_assert();
1676 
1677 	sc = disk->d_softc;
1678 	KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
1679 	    ("Device not in RUNNING state (%s, %u).", sc->sc_name,
1680 	    sc->sc_state));
1681 
1682 	G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s.", sc->sc_name,
1683 	    g_mirror_get_diskname(disk));
1684 	disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1685 	KASSERT(disk->d_sync.ds_consumer == NULL,
1686 	    ("Sync consumer already exists (device=%s, disk=%s).",
1687 	    sc->sc_name, g_mirror_get_diskname(disk)));
1688 	disk->d_sync.ds_consumer = g_new_consumer(sc->sc_sync.ds_geom);
1689 	disk->d_sync.ds_consumer->private = disk;
1690 	disk->d_sync.ds_consumer->index = 0;
1691 	error = g_attach(disk->d_sync.ds_consumer, disk->d_softc->sc_provider);
1692 	KASSERT(error == 0, ("Cannot attach to %s (error=%d).",
1693 	    disk->d_softc->sc_name, error));
1694 	error = g_access(disk->d_sync.ds_consumer, 1, 0, 0);
1695 	KASSERT(error == 0, ("Cannot open %s (error=%d).",
1696 	    disk->d_softc->sc_name, error));
1697 	disk->d_sync.ds_data = malloc(MAXPHYS, M_MIRROR, M_WAITOK);
1698 	sc->sc_sync.ds_ndisks++;
1699 }
1700 
1701 /*
1702  * Stop synchronization process.
1703  * type: 0 - synchronization finished
1704  *       1 - synchronization stopped
1705  */
1706 static void
1707 g_mirror_sync_stop(struct g_mirror_disk *disk, int type)
1708 {
1709 
1710 	g_topology_assert();
1711 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
1712 	    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
1713 	    g_mirror_disk_state2str(disk->d_state)));
1714 	if (disk->d_sync.ds_consumer == NULL)
1715 		return;
1716 
1717 	if (type == 0) {
1718 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s finished.",
1719 		    disk->d_softc->sc_name, g_mirror_get_diskname(disk));
1720 	} else /* if (type == 1) */ {
1721 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s stopped.",
1722 		    disk->d_softc->sc_name, g_mirror_get_diskname(disk));
1723 	}
1724 	g_mirror_kill_consumer(disk->d_softc, disk->d_sync.ds_consumer);
1725 	free(disk->d_sync.ds_data, M_MIRROR);
1726 	disk->d_sync.ds_consumer = NULL;
1727 	disk->d_softc->sc_sync.ds_ndisks--;
1728 	disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
1729 }
1730 
1731 static void
1732 g_mirror_launch_provider(struct g_mirror_softc *sc)
1733 {
1734 	struct g_mirror_disk *disk;
1735 	struct g_provider *pp;
1736 
1737 	g_topology_assert();
1738 
1739 	pp = g_new_providerf(sc->sc_geom, "mirror/%s", sc->sc_name);
1740 	pp->mediasize = sc->sc_mediasize;
1741 	pp->sectorsize = sc->sc_sectorsize;
1742 	sc->sc_provider = pp;
1743 	g_error_provider(pp, 0);
1744 	G_MIRROR_DEBUG(0, "Device %s: provider %s launched.", sc->sc_name,
1745 	    pp->name);
1746 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1747 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
1748 			g_mirror_sync_start(disk);
1749 	}
1750 }
1751 
1752 static void
1753 g_mirror_destroy_provider(struct g_mirror_softc *sc)
1754 {
1755 	struct g_mirror_disk *disk;
1756 	struct bio *bp;
1757 
1758 	g_topology_assert();
1759 	KASSERT(sc->sc_provider != NULL, ("NULL provider (device=%s).",
1760 	    sc->sc_name));
1761 
1762 	g_error_provider(sc->sc_provider, ENXIO);
1763 	mtx_lock(&sc->sc_queue_mtx);
1764 	while ((bp = bioq_first(&sc->sc_queue)) != NULL) {
1765 		bioq_remove(&sc->sc_queue, bp);
1766 		g_io_deliver(bp, ENXIO);
1767 	}
1768 	mtx_unlock(&sc->sc_queue_mtx);
1769 	G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.", sc->sc_name,
1770 	    sc->sc_provider->name);
1771 	sc->sc_provider->flags |= G_PF_WITHER;
1772 	g_orphan_provider(sc->sc_provider, ENXIO);
1773 	sc->sc_provider = NULL;
1774 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1775 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
1776 			g_mirror_sync_stop(disk, 1);
1777 	}
1778 }
1779 
1780 static void
1781 g_mirror_go(void *arg)
1782 {
1783 	struct g_mirror_softc *sc;
1784 
1785 	sc = arg;
1786 	G_MIRROR_DEBUG(0, "Force device %s start due to timeout.", sc->sc_name);
1787 	g_mirror_event_send(sc, 0,
1788 	    G_MIRROR_EVENT_DONTWAIT | G_MIRROR_EVENT_DEVICE);
1789 }
1790 
1791 static u_int
1792 g_mirror_determine_state(struct g_mirror_disk *disk)
1793 {
1794 	struct g_mirror_softc *sc;
1795 	u_int state;
1796 
1797 	sc = disk->d_softc;
1798 	if (sc->sc_syncid == disk->d_sync.ds_syncid) {
1799 		if ((disk->d_flags &
1800 		    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
1801 			/* Disk does not need synchronization. */
1802 			state = G_MIRROR_DISK_STATE_ACTIVE;
1803 		} else {
1804 			if ((sc->sc_flags &
1805 			     G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0  ||
1806 			    (disk->d_flags &
1807 			     G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
1808 				/*
1809 				 * We can start synchronization from
1810 				 * the stored offset.
1811 				 */
1812 				state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
1813 			} else {
1814 				state = G_MIRROR_DISK_STATE_STALE;
1815 			}
1816 		}
1817 	} else if (disk->d_sync.ds_syncid < sc->sc_syncid) {
1818 		/*
1819 		 * Reset all synchronization data for this disk,
1820 		 * because if it even was synchronized, it was
1821 		 * synchronized to disks with different syncid.
1822 		 */
1823 		disk->d_flags |= G_MIRROR_DISK_FLAG_SYNCHRONIZING;
1824 		disk->d_sync.ds_offset = 0;
1825 		disk->d_sync.ds_offset_done = 0;
1826 		disk->d_sync.ds_syncid = sc->sc_syncid;
1827 		if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
1828 		    (disk->d_flags & G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
1829 			state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
1830 		} else {
1831 			state = G_MIRROR_DISK_STATE_STALE;
1832 		}
1833 	} else /* if (sc->sc_syncid < disk->d_sync.ds_syncid) */ {
1834 		/*
1835 		 * Not good, NOT GOOD!
1836 		 * It means that mirror was started on stale disks
1837 		 * and more fresh disk just arrive.
1838 		 * If there were writes, mirror is fucked up, sorry.
1839 		 * I think the best choice here is don't touch
1840 		 * this disk and inform the user laudly.
1841 		 */
1842 		G_MIRROR_DEBUG(0, "Device %s was started before the freshest "
1843 		    "disk (%s) arrives!! It will not be connected to the "
1844 		    "running device.", sc->sc_name,
1845 		    g_mirror_get_diskname(disk));
1846 		g_mirror_destroy_disk(disk);
1847 		state = G_MIRROR_DISK_STATE_NONE;
1848 		/* Return immediately, because disk was destroyed. */
1849 		return (state);
1850 	}
1851 	G_MIRROR_DEBUG(3, "State for %s disk: %s.",
1852 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(state));
1853 	return (state);
1854 }
1855 
1856 /*
1857  * Update device state.
1858  */
1859 static void
1860 g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force)
1861 {
1862 	struct g_mirror_disk *disk;
1863 	u_int state;
1864 
1865 	g_topology_assert();
1866 
1867 	switch (sc->sc_state) {
1868 	case G_MIRROR_DEVICE_STATE_STARTING:
1869 	    {
1870 		struct g_mirror_disk *pdisk, *tdisk;
1871 		u_int dirty, ndisks, genid, syncid;
1872 
1873 		KASSERT(sc->sc_provider == NULL,
1874 		    ("Non-NULL provider in STARTING state (%s).", sc->sc_name));
1875 		/*
1876 		 * Are we ready? We are, if all disks are connected or
1877 		 * if we have any disks and 'force' is true.
1878 		 */
1879 		if ((force && g_mirror_ndisks(sc, -1) > 0) ||
1880 		    sc->sc_ndisks == g_mirror_ndisks(sc, -1)) {
1881 			;
1882 		} else if (g_mirror_ndisks(sc, -1) == 0) {
1883 			/*
1884 			 * Disks went down in starting phase, so destroy
1885 			 * device.
1886 			 */
1887 			callout_drain(&sc->sc_callout);
1888 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
1889 			return;
1890 		} else {
1891 			return;
1892 		}
1893 
1894 		/*
1895 		 * Activate all disks with the biggest syncid.
1896 		 */
1897 		if (force) {
1898 			/*
1899 			 * If 'force' is true, we have been called due to
1900 			 * timeout, so don't bother canceling timeout.
1901 			 */
1902 			ndisks = 0;
1903 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1904 				if ((disk->d_flags &
1905 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
1906 					ndisks++;
1907 				}
1908 			}
1909 			if (ndisks == 0) {
1910 				/* No valid disks found, destroy device. */
1911 				sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
1912 				return;
1913 			}
1914 		} else {
1915 			/* Cancel timeout. */
1916 			callout_drain(&sc->sc_callout);
1917 		}
1918 
1919 		/*
1920 		 * Find the biggest genid.
1921 		 */
1922 		genid = 0;
1923 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1924 			if (disk->d_genid > genid)
1925 				genid = disk->d_genid;
1926 		}
1927 		sc->sc_genid = genid;
1928 		/*
1929 		 * Remove all disks without the biggest genid.
1930 		 */
1931 		LIST_FOREACH_SAFE(disk, &sc->sc_disks, d_next, tdisk) {
1932 			if (disk->d_genid < genid) {
1933 				G_MIRROR_DEBUG(0,
1934 				    "Component %s (device %s) broken, skipping.",
1935 				    g_mirror_get_diskname(disk), sc->sc_name);
1936 				g_mirror_destroy_disk(disk);
1937 			}
1938 		}
1939 
1940 		/*
1941 		 * Find the biggest syncid.
1942 		 */
1943 		syncid = 0;
1944 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1945 			if (disk->d_sync.ds_syncid > syncid)
1946 				syncid = disk->d_sync.ds_syncid;
1947 		}
1948 
1949 		/*
1950 		 * Here we need to look for dirty disks and if all disks
1951 		 * with the biggest syncid are dirty, we have to choose
1952 		 * one with the biggest priority and rebuild the rest.
1953 		 */
1954 		/*
1955 		 * Find the number of dirty disks with the biggest syncid.
1956 		 * Find the number of disks with the biggest syncid.
1957 		 * While here, find a disk with the biggest priority.
1958 		 */
1959 		dirty = ndisks = 0;
1960 		pdisk = NULL;
1961 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1962 			if (disk->d_sync.ds_syncid != syncid)
1963 				continue;
1964 			if ((disk->d_flags &
1965 			    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
1966 				continue;
1967 			}
1968 			ndisks++;
1969 			if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
1970 				dirty++;
1971 				if (pdisk == NULL ||
1972 				    pdisk->d_priority < disk->d_priority) {
1973 					pdisk = disk;
1974 				}
1975 			}
1976 		}
1977 		if (dirty == 0) {
1978 			/* No dirty disks at all, great. */
1979 		} else if (dirty == ndisks) {
1980 			/*
1981 			 * Force synchronization for all dirty disks except one
1982 			 * with the biggest priority.
1983 			 */
1984 			KASSERT(pdisk != NULL, ("pdisk == NULL"));
1985 			G_MIRROR_DEBUG(1, "Using disk %s (device %s) as a "
1986 			    "master disk for synchronization.",
1987 			    g_mirror_get_diskname(pdisk), sc->sc_name);
1988 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1989 				if (disk->d_sync.ds_syncid != syncid)
1990 					continue;
1991 				if ((disk->d_flags &
1992 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
1993 					continue;
1994 				}
1995 				KASSERT((disk->d_flags &
1996 				    G_MIRROR_DISK_FLAG_DIRTY) != 0,
1997 				    ("Disk %s isn't marked as dirty.",
1998 				    g_mirror_get_diskname(disk)));
1999 				/* Skip the disk with the biggest priority. */
2000 				if (disk == pdisk)
2001 					continue;
2002 				disk->d_sync.ds_syncid = 0;
2003 			}
2004 		} else if (dirty < ndisks) {
2005 			/*
2006 			 * Force synchronization for all dirty disks.
2007 			 * We have some non-dirty disks.
2008 			 */
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 				if ((disk->d_flags &
2017 				    G_MIRROR_DISK_FLAG_DIRTY) == 0) {
2018 					continue;
2019 				}
2020 				disk->d_sync.ds_syncid = 0;
2021 			}
2022 		}
2023 
2024 		/* Reset hint. */
2025 		sc->sc_hint = NULL;
2026 		sc->sc_syncid = syncid;
2027 		if (force) {
2028 			/* Remember to bump syncid on first write. */
2029 			sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2030 		}
2031 		state = G_MIRROR_DEVICE_STATE_RUNNING;
2032 		G_MIRROR_DEBUG(1, "Device %s state changed from %s to %s.",
2033 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state),
2034 		    g_mirror_device_state2str(state));
2035 		sc->sc_state = state;
2036 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2037 			state = g_mirror_determine_state(disk);
2038 			g_mirror_event_send(disk, state,
2039 			    G_MIRROR_EVENT_DONTWAIT);
2040 			if (state == G_MIRROR_DISK_STATE_STALE)
2041 				sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2042 		}
2043 		wakeup(&g_mirror_class);
2044 		break;
2045 	    }
2046 	case G_MIRROR_DEVICE_STATE_RUNNING:
2047 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 0 &&
2048 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2049 			/*
2050 			 * No active disks or no disks at all,
2051 			 * so destroy device.
2052 			 */
2053 			if (sc->sc_provider != NULL)
2054 				g_mirror_destroy_provider(sc);
2055 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2056 			break;
2057 		} else if (g_mirror_ndisks(sc,
2058 		    G_MIRROR_DISK_STATE_ACTIVE) > 0 &&
2059 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2060 			/*
2061 			 * We have active disks, launch provider if it doesn't
2062 			 * exist.
2063 			 */
2064 			if (sc->sc_provider == NULL)
2065 				g_mirror_launch_provider(sc);
2066 		}
2067 		/*
2068 		 * Genid should be bumped immediately, so do it here.
2069 		 */
2070 		if ((sc->sc_bump_id & G_MIRROR_BUMP_GENID) != 0) {
2071 			sc->sc_bump_id &= ~G_MIRROR_BUMP_GENID;
2072 			g_mirror_bump_genid(sc);
2073 		}
2074 		break;
2075 	default:
2076 		KASSERT(1 == 0, ("Wrong device state (%s, %s).",
2077 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state)));
2078 		break;
2079 	}
2080 }
2081 
2082 /*
2083  * Update disk state and device state if needed.
2084  */
2085 #define	DISK_STATE_CHANGED()	G_MIRROR_DEBUG(1,			\
2086 	"Disk %s state changed from %s to %s (device %s).",		\
2087 	g_mirror_get_diskname(disk),					\
2088 	g_mirror_disk_state2str(disk->d_state),				\
2089 	g_mirror_disk_state2str(state), sc->sc_name)
2090 static int
2091 g_mirror_update_disk(struct g_mirror_disk *disk, u_int state)
2092 {
2093 	struct g_mirror_softc *sc;
2094 
2095 	g_topology_assert();
2096 
2097 	sc = disk->d_softc;
2098 again:
2099 	G_MIRROR_DEBUG(3, "Changing disk %s state from %s to %s.",
2100 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(disk->d_state),
2101 	    g_mirror_disk_state2str(state));
2102 	switch (state) {
2103 	case G_MIRROR_DISK_STATE_NEW:
2104 		/*
2105 		 * Possible scenarios:
2106 		 * 1. New disk arrive.
2107 		 */
2108 		/* Previous state should be NONE. */
2109 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NONE,
2110 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2111 		    g_mirror_disk_state2str(disk->d_state)));
2112 		DISK_STATE_CHANGED();
2113 
2114 		disk->d_state = state;
2115 		if (LIST_EMPTY(&sc->sc_disks))
2116 			LIST_INSERT_HEAD(&sc->sc_disks, disk, d_next);
2117 		else {
2118 			struct g_mirror_disk *dp;
2119 
2120 			LIST_FOREACH(dp, &sc->sc_disks, d_next) {
2121 				if (disk->d_priority >= dp->d_priority) {
2122 					LIST_INSERT_BEFORE(dp, disk, d_next);
2123 					dp = NULL;
2124 					break;
2125 				}
2126 				if (LIST_NEXT(dp, d_next) == NULL)
2127 					break;
2128 			}
2129 			if (dp != NULL)
2130 				LIST_INSERT_AFTER(dp, disk, d_next);
2131 		}
2132 		G_MIRROR_DEBUG(0, "Device %s: provider %s detected.",
2133 		    sc->sc_name, g_mirror_get_diskname(disk));
2134 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
2135 			break;
2136 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2137 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2138 		    g_mirror_device_state2str(sc->sc_state),
2139 		    g_mirror_get_diskname(disk),
2140 		    g_mirror_disk_state2str(disk->d_state)));
2141 		state = g_mirror_determine_state(disk);
2142 		if (state != G_MIRROR_DISK_STATE_NONE)
2143 			goto again;
2144 		break;
2145 	case G_MIRROR_DISK_STATE_ACTIVE:
2146 		/*
2147 		 * Possible scenarios:
2148 		 * 1. New disk does not need synchronization.
2149 		 * 2. Synchronization process finished successfully.
2150 		 */
2151 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2152 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2153 		    g_mirror_device_state2str(sc->sc_state),
2154 		    g_mirror_get_diskname(disk),
2155 		    g_mirror_disk_state2str(disk->d_state)));
2156 		/* Previous state should be NEW or SYNCHRONIZING. */
2157 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW ||
2158 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2159 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2160 		    g_mirror_disk_state2str(disk->d_state)));
2161 		DISK_STATE_CHANGED();
2162 
2163 		if (disk->d_state == G_MIRROR_DISK_STATE_NEW)
2164 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2165 		else if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2166 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2167 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_FORCE_SYNC;
2168 			g_mirror_sync_stop(disk, 0);
2169 		}
2170 		disk->d_state = state;
2171 		disk->d_sync.ds_offset = 0;
2172 		disk->d_sync.ds_offset_done = 0;
2173 		g_mirror_update_access(disk);
2174 		g_mirror_update_metadata(disk);
2175 		G_MIRROR_DEBUG(0, "Device %s: provider %s activated.",
2176 		    sc->sc_name, g_mirror_get_diskname(disk));
2177 		break;
2178 	case G_MIRROR_DISK_STATE_STALE:
2179 		/*
2180 		 * Possible scenarios:
2181 		 * 1. Stale disk was connected.
2182 		 */
2183 		/* Previous state should be NEW. */
2184 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2185 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2186 		    g_mirror_disk_state2str(disk->d_state)));
2187 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2188 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2189 		    g_mirror_device_state2str(sc->sc_state),
2190 		    g_mirror_get_diskname(disk),
2191 		    g_mirror_disk_state2str(disk->d_state)));
2192 		/*
2193 		 * STALE state is only possible if device is marked
2194 		 * NOAUTOSYNC.
2195 		 */
2196 		KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) != 0,
2197 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2198 		    g_mirror_device_state2str(sc->sc_state),
2199 		    g_mirror_get_diskname(disk),
2200 		    g_mirror_disk_state2str(disk->d_state)));
2201 		DISK_STATE_CHANGED();
2202 
2203 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2204 		disk->d_state = state;
2205 		g_mirror_update_metadata(disk);
2206 		G_MIRROR_DEBUG(0, "Device %s: provider %s is stale.",
2207 		    sc->sc_name, g_mirror_get_diskname(disk));
2208 		break;
2209 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
2210 		/*
2211 		 * Possible scenarios:
2212 		 * 1. Disk which needs synchronization was connected.
2213 		 */
2214 		/* Previous state should be NEW. */
2215 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2216 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2217 		    g_mirror_disk_state2str(disk->d_state)));
2218 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2219 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2220 		    g_mirror_device_state2str(sc->sc_state),
2221 		    g_mirror_get_diskname(disk),
2222 		    g_mirror_disk_state2str(disk->d_state)));
2223 		DISK_STATE_CHANGED();
2224 
2225 		if (disk->d_state == G_MIRROR_DISK_STATE_NEW)
2226 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2227 		disk->d_state = state;
2228 		if (sc->sc_provider != NULL) {
2229 			g_mirror_sync_start(disk);
2230 			g_mirror_update_metadata(disk);
2231 		}
2232 		break;
2233 	case G_MIRROR_DISK_STATE_DISCONNECTED:
2234 		/*
2235 		 * Possible scenarios:
2236 		 * 1. Device wasn't running yet, but disk disappear.
2237 		 * 2. Disk was active and disapppear.
2238 		 * 3. Disk disappear during synchronization process.
2239 		 */
2240 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING) {
2241 			/*
2242 			 * Previous state should be ACTIVE, STALE or
2243 			 * SYNCHRONIZING.
2244 			 */
2245 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
2246 			    disk->d_state == G_MIRROR_DISK_STATE_STALE ||
2247 			    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2248 			    ("Wrong disk state (%s, %s).",
2249 			    g_mirror_get_diskname(disk),
2250 			    g_mirror_disk_state2str(disk->d_state)));
2251 		} else if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING) {
2252 			/* Previous state should be NEW. */
2253 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2254 			    ("Wrong disk state (%s, %s).",
2255 			    g_mirror_get_diskname(disk),
2256 			    g_mirror_disk_state2str(disk->d_state)));
2257 			/*
2258 			 * Reset bumping syncid if disk disappeared in STARTING
2259 			 * state.
2260 			 */
2261 			if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0)
2262 				sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
2263 #ifdef	INVARIANTS
2264 		} else {
2265 			KASSERT(1 == 0, ("Wrong device state (%s, %s, %s, %s).",
2266 			    sc->sc_name,
2267 			    g_mirror_device_state2str(sc->sc_state),
2268 			    g_mirror_get_diskname(disk),
2269 			    g_mirror_disk_state2str(disk->d_state)));
2270 #endif
2271 		}
2272 		DISK_STATE_CHANGED();
2273 		G_MIRROR_DEBUG(0, "Device %s: provider %s disconnected.",
2274 		    sc->sc_name, g_mirror_get_diskname(disk));
2275 
2276 		g_mirror_destroy_disk(disk);
2277 		break;
2278 	case G_MIRROR_DISK_STATE_DESTROY:
2279 	    {
2280 		int error;
2281 
2282 		error = g_mirror_clear_metadata(disk);
2283 		if (error != 0)
2284 			return (error);
2285 		DISK_STATE_CHANGED();
2286 		G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.",
2287 		    sc->sc_name, g_mirror_get_diskname(disk));
2288 
2289 		g_mirror_destroy_disk(disk);
2290 		sc->sc_ndisks--;
2291 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2292 			g_mirror_update_metadata(disk);
2293 		}
2294 		break;
2295 	    }
2296 	default:
2297 		KASSERT(1 == 0, ("Unknown state (%u).", state));
2298 		break;
2299 	}
2300 	return (0);
2301 }
2302 #undef	DISK_STATE_CHANGED
2303 
2304 int
2305 g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md)
2306 {
2307 	struct g_provider *pp;
2308 	u_char *buf;
2309 	int error;
2310 
2311 	g_topology_assert();
2312 
2313 	error = g_access(cp, 1, 0, 0);
2314 	if (error != 0)
2315 		return (error);
2316 	pp = cp->provider;
2317 	g_topology_unlock();
2318 	/* Metadata are stored on last sector. */
2319 	buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
2320 	    &error);
2321 	g_topology_lock();
2322 	g_access(cp, -1, 0, 0);
2323 	if (error != 0) {
2324 		G_MIRROR_DEBUG(1, "Cannot read metadata from %s (error=%d).",
2325 		    cp->provider->name, error);
2326 		if (buf != NULL)
2327 			g_free(buf);
2328 		return (error);
2329 	}
2330 
2331 	/* Decode metadata. */
2332 	error = mirror_metadata_decode(buf, md);
2333 	g_free(buf);
2334 	if (strcmp(md->md_magic, G_MIRROR_MAGIC) != 0)
2335 		return (EINVAL);
2336 	if (md->md_version > G_MIRROR_VERSION) {
2337 		G_MIRROR_DEBUG(0,
2338 		    "Kernel module is too old to handle metadata from %s.",
2339 		    cp->provider->name);
2340 		return (EINVAL);
2341 	}
2342 	if (error != 0) {
2343 		G_MIRROR_DEBUG(1, "MD5 metadata hash mismatch for provider %s.",
2344 		    cp->provider->name);
2345 		return (error);
2346 	}
2347 
2348 	return (0);
2349 }
2350 
2351 static int
2352 g_mirror_check_metadata(struct g_mirror_softc *sc, struct g_provider *pp,
2353     struct g_mirror_metadata *md)
2354 {
2355 
2356 	if (g_mirror_id2disk(sc, md->md_did) != NULL) {
2357 		G_MIRROR_DEBUG(1, "Disk %s (id=%u) already exists, skipping.",
2358 		    pp->name, md->md_did);
2359 		return (EEXIST);
2360 	}
2361 	if (md->md_all != sc->sc_ndisks) {
2362 		G_MIRROR_DEBUG(1,
2363 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2364 		    "md_all", pp->name, sc->sc_name);
2365 		return (EINVAL);
2366 	}
2367 	if (md->md_slice != sc->sc_slice) {
2368 		G_MIRROR_DEBUG(1,
2369 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2370 		    "md_slice", pp->name, sc->sc_name);
2371 		return (EINVAL);
2372 	}
2373 	if (md->md_balance != sc->sc_balance) {
2374 		G_MIRROR_DEBUG(1,
2375 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2376 		    "md_balance", pp->name, sc->sc_name);
2377 		return (EINVAL);
2378 	}
2379 	if (md->md_mediasize != sc->sc_mediasize) {
2380 		G_MIRROR_DEBUG(1,
2381 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2382 		    "md_mediasize", pp->name, sc->sc_name);
2383 		return (EINVAL);
2384 	}
2385 	if (sc->sc_mediasize > pp->mediasize) {
2386 		G_MIRROR_DEBUG(1,
2387 		    "Invalid size of disk %s (device %s), skipping.", pp->name,
2388 		    sc->sc_name);
2389 		return (EINVAL);
2390 	}
2391 	if (md->md_sectorsize != sc->sc_sectorsize) {
2392 		G_MIRROR_DEBUG(1,
2393 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2394 		    "md_sectorsize", pp->name, sc->sc_name);
2395 		return (EINVAL);
2396 	}
2397 	if ((sc->sc_sectorsize % pp->sectorsize) != 0) {
2398 		G_MIRROR_DEBUG(1,
2399 		    "Invalid sector size of disk %s (device %s), skipping.",
2400 		    pp->name, sc->sc_name);
2401 		return (EINVAL);
2402 	}
2403 	if ((md->md_mflags & ~G_MIRROR_DEVICE_FLAG_MASK) != 0) {
2404 		G_MIRROR_DEBUG(1,
2405 		    "Invalid device flags on disk %s (device %s), skipping.",
2406 		    pp->name, sc->sc_name);
2407 		return (EINVAL);
2408 	}
2409 	if ((md->md_dflags & ~G_MIRROR_DISK_FLAG_MASK) != 0) {
2410 		G_MIRROR_DEBUG(1,
2411 		    "Invalid disk flags on disk %s (device %s), skipping.",
2412 		    pp->name, sc->sc_name);
2413 		return (EINVAL);
2414 	}
2415 	return (0);
2416 }
2417 
2418 int
2419 g_mirror_add_disk(struct g_mirror_softc *sc, struct g_provider *pp,
2420     struct g_mirror_metadata *md)
2421 {
2422 	struct g_mirror_disk *disk;
2423 	int error;
2424 
2425 	g_topology_assert();
2426 	G_MIRROR_DEBUG(2, "Adding disk %s.", pp->name);
2427 
2428 	error = g_mirror_check_metadata(sc, pp, md);
2429 	if (error != 0)
2430 		return (error);
2431 	if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING &&
2432 	    md->md_genid < sc->sc_genid) {
2433 		G_MIRROR_DEBUG(0, "Component %s (device %s) broken, skipping.",
2434 		    pp->name, sc->sc_name);
2435 		return (EINVAL);
2436 	}
2437 	disk = g_mirror_init_disk(sc, pp, md, &error);
2438 	if (disk == NULL)
2439 		return (error);
2440 	error = g_mirror_event_send(disk, G_MIRROR_DISK_STATE_NEW,
2441 	    G_MIRROR_EVENT_WAIT);
2442 	if (error != 0)
2443 		return (error);
2444 	if (md->md_version < G_MIRROR_VERSION) {
2445 		G_MIRROR_DEBUG(0, "Upgrading metadata on %s (v%d->v%d).",
2446 		    pp->name, md->md_version, G_MIRROR_VERSION);
2447 		g_mirror_update_metadata(disk);
2448 	}
2449 	return (0);
2450 }
2451 
2452 static int
2453 g_mirror_access(struct g_provider *pp, int acr, int acw, int ace)
2454 {
2455 	struct g_mirror_softc *sc;
2456 	struct g_mirror_disk *disk;
2457 	int dcr, dcw, dce;
2458 
2459 	g_topology_assert();
2460 	G_MIRROR_DEBUG(2, "Access request for %s: r%dw%de%d.", pp->name, acr,
2461 	    acw, ace);
2462 
2463 	dcr = pp->acr + acr;
2464 	dcw = pp->acw + acw;
2465 	dce = pp->ace + ace;
2466 
2467 	sc = pp->geom->softc;
2468 	if (sc == NULL || LIST_EMPTY(&sc->sc_disks) ||
2469 	    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
2470 		if (acr <= 0 && acw <= 0 && ace <= 0)
2471 			return (0);
2472 		else
2473 			return (ENXIO);
2474 	}
2475 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2476 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
2477 			continue;
2478 		/*
2479 		 * Mark disk as dirty on open and unmark on close.
2480 		 */
2481 		if (pp->acw == 0 && dcw > 0) {
2482 			G_MIRROR_DEBUG(1,
2483 			    "Disk %s (device %s) marked as dirty.",
2484 			    g_mirror_get_diskname(disk), sc->sc_name);
2485 			disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
2486 			g_mirror_update_metadata(disk);
2487 		} else if (pp->acw > 0 && dcw == 0) {
2488 			G_MIRROR_DEBUG(1,
2489 			    "Disk %s (device %s) marked as clean.",
2490 			    g_mirror_get_diskname(disk), sc->sc_name);
2491 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2492 			g_mirror_update_metadata(disk);
2493 		}
2494 	}
2495 	return (0);
2496 }
2497 
2498 static struct g_geom *
2499 g_mirror_create(struct g_class *mp, const struct g_mirror_metadata *md)
2500 {
2501 	struct g_mirror_softc *sc;
2502 	struct g_geom *gp;
2503 	int error, timeout;
2504 
2505 	g_topology_assert();
2506 	G_MIRROR_DEBUG(1, "Creating device %s (id=%u).", md->md_name,
2507 	    md->md_mid);
2508 
2509 	/* One disk is minimum. */
2510 	if (md->md_all < 1)
2511 		return (NULL);
2512 	/*
2513 	 * Action geom.
2514 	 */
2515 	gp = g_new_geomf(mp, "%s", md->md_name);
2516 	sc = malloc(sizeof(*sc), M_MIRROR, M_WAITOK | M_ZERO);
2517 	gp->start = g_mirror_start;
2518 	gp->orphan = g_mirror_orphan;
2519 	gp->access = g_mirror_access;
2520 	gp->dumpconf = g_mirror_dumpconf;
2521 
2522 	sc->sc_id = md->md_mid;
2523 	sc->sc_slice = md->md_slice;
2524 	sc->sc_balance = md->md_balance;
2525 	sc->sc_mediasize = md->md_mediasize;
2526 	sc->sc_sectorsize = md->md_sectorsize;
2527 	sc->sc_ndisks = md->md_all;
2528 	sc->sc_flags = md->md_mflags;
2529 	sc->sc_bump_id = 0;
2530 	sc->sc_idle = 0;
2531 	bioq_init(&sc->sc_queue);
2532 	mtx_init(&sc->sc_queue_mtx, "gmirror:queue", NULL, MTX_DEF);
2533 	LIST_INIT(&sc->sc_disks);
2534 	TAILQ_INIT(&sc->sc_events);
2535 	mtx_init(&sc->sc_events_mtx, "gmirror:events", NULL, MTX_DEF);
2536 	callout_init(&sc->sc_callout, CALLOUT_MPSAFE);
2537 	sc->sc_state = G_MIRROR_DEVICE_STATE_STARTING;
2538 	gp->softc = sc;
2539 	sc->sc_geom = gp;
2540 	sc->sc_provider = NULL;
2541 	/*
2542 	 * Synchronization geom.
2543 	 */
2544 	gp = g_new_geomf(mp, "%s.sync", md->md_name);
2545 	gp->softc = sc;
2546 	gp->orphan = g_mirror_orphan;
2547 	sc->sc_sync.ds_geom = gp;
2548 	sc->sc_sync.ds_ndisks = 0;
2549 	error = kthread_create(g_mirror_worker, sc, &sc->sc_worker, 0, 0,
2550 	    "g_mirror %s", md->md_name);
2551 	if (error != 0) {
2552 		G_MIRROR_DEBUG(1, "Cannot create kernel thread for %s.",
2553 		    sc->sc_name);
2554 		g_destroy_geom(sc->sc_sync.ds_geom);
2555 		mtx_destroy(&sc->sc_events_mtx);
2556 		mtx_destroy(&sc->sc_queue_mtx);
2557 		g_destroy_geom(sc->sc_geom);
2558 		free(sc, M_MIRROR);
2559 		return (NULL);
2560 	}
2561 
2562 	G_MIRROR_DEBUG(0, "Device %s created (id=%u).", sc->sc_name, sc->sc_id);
2563 
2564 	/*
2565 	 * Run timeout.
2566 	 */
2567 	timeout = g_mirror_timeout * hz;
2568 	callout_reset(&sc->sc_callout, timeout, g_mirror_go, sc);
2569 	return (sc->sc_geom);
2570 }
2571 
2572 int
2573 g_mirror_destroy(struct g_mirror_softc *sc, boolean_t force)
2574 {
2575 	struct g_provider *pp;
2576 
2577 	g_topology_assert();
2578 
2579 	if (sc == NULL)
2580 		return (ENXIO);
2581 	pp = sc->sc_provider;
2582 	if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
2583 		if (force) {
2584 			G_MIRROR_DEBUG(1, "Device %s is still open, so it "
2585 			    "can't be definitely removed.", pp->name);
2586 		} else {
2587 			G_MIRROR_DEBUG(1,
2588 			    "Device %s is still open (r%dw%de%d).", pp->name,
2589 			    pp->acr, pp->acw, pp->ace);
2590 			return (EBUSY);
2591 		}
2592 	}
2593 
2594 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2595 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_WAIT;
2596 	g_topology_unlock();
2597 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
2598 	mtx_lock(&sc->sc_queue_mtx);
2599 	wakeup(sc);
2600 	mtx_unlock(&sc->sc_queue_mtx);
2601 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, &sc->sc_worker);
2602 	while (sc->sc_worker != NULL)
2603 		tsleep(&sc->sc_worker, PRIBIO, "m:destroy", hz / 5);
2604 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, &sc->sc_worker);
2605 	g_topology_lock();
2606 	g_mirror_destroy_device(sc);
2607 	free(sc, M_MIRROR);
2608 	return (0);
2609 }
2610 
2611 static void
2612 g_mirror_taste_orphan(struct g_consumer *cp)
2613 {
2614 
2615 	KASSERT(1 == 0, ("%s called while tasting %s.", __func__,
2616 	    cp->provider->name));
2617 }
2618 
2619 static struct g_geom *
2620 g_mirror_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
2621 {
2622 	struct g_mirror_metadata md;
2623 	struct g_mirror_softc *sc;
2624 	struct g_consumer *cp;
2625 	struct g_geom *gp;
2626 	int error;
2627 
2628 	g_topology_assert();
2629 	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
2630 	G_MIRROR_DEBUG(2, "Tasting %s.", pp->name);
2631 
2632 	gp = g_new_geomf(mp, "mirror:taste");
2633 	/*
2634 	 * This orphan function should be never called.
2635 	 */
2636 	gp->orphan = g_mirror_taste_orphan;
2637 	cp = g_new_consumer(gp);
2638 	g_attach(cp, pp);
2639 	error = g_mirror_read_metadata(cp, &md);
2640 	g_detach(cp);
2641 	g_destroy_consumer(cp);
2642 	g_destroy_geom(gp);
2643 	if (error != 0)
2644 		return (NULL);
2645 	gp = NULL;
2646 
2647 	if (md.md_provider[0] != '\0' && strcmp(md.md_provider, pp->name) != 0)
2648 		return (NULL);
2649 	if ((md.md_dflags & G_MIRROR_DISK_FLAG_INACTIVE) != 0) {
2650 		G_MIRROR_DEBUG(0,
2651 		    "Device %s: provider %s marked as inactive, skipping.",
2652 		    md.md_name, pp->name);
2653 		return (NULL);
2654 	}
2655 	if (g_mirror_debug >= 2)
2656 		mirror_metadata_dump(&md);
2657 
2658 	/*
2659 	 * Let's check if device already exists.
2660 	 */
2661 	sc = NULL;
2662 	LIST_FOREACH(gp, &mp->geom, geom) {
2663 		sc = gp->softc;
2664 		if (sc == NULL)
2665 			continue;
2666 		if (sc->sc_sync.ds_geom == gp)
2667 			continue;
2668 		if (strcmp(md.md_name, sc->sc_name) != 0)
2669 			continue;
2670 		if (md.md_mid != sc->sc_id) {
2671 			G_MIRROR_DEBUG(0, "Device %s already configured.",
2672 			    sc->sc_name);
2673 			return (NULL);
2674 		}
2675 		break;
2676 	}
2677 	if (gp == NULL) {
2678 		gp = g_mirror_create(mp, &md);
2679 		if (gp == NULL) {
2680 			G_MIRROR_DEBUG(0, "Cannot create device %s.",
2681 			    md.md_name);
2682 			return (NULL);
2683 		}
2684 		sc = gp->softc;
2685 	}
2686 	G_MIRROR_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
2687 	error = g_mirror_add_disk(sc, pp, &md);
2688 	if (error != 0) {
2689 		G_MIRROR_DEBUG(0, "Cannot add disk %s to %s (error=%d).",
2690 		    pp->name, gp->name, error);
2691 		if (LIST_EMPTY(&sc->sc_disks))
2692 			g_mirror_destroy(sc, 1);
2693 		return (NULL);
2694 	}
2695 	return (gp);
2696 }
2697 
2698 static int
2699 g_mirror_destroy_geom(struct gctl_req *req __unused,
2700     struct g_class *mp __unused, struct g_geom *gp)
2701 {
2702 
2703 	return (g_mirror_destroy(gp->softc, 0));
2704 }
2705 
2706 static void
2707 g_mirror_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
2708     struct g_consumer *cp, struct g_provider *pp)
2709 {
2710 	struct g_mirror_softc *sc;
2711 
2712 	g_topology_assert();
2713 
2714 	sc = gp->softc;
2715 	if (sc == NULL)
2716 		return;
2717 	/* Skip synchronization geom. */
2718 	if (gp == sc->sc_sync.ds_geom)
2719 		return;
2720 	if (pp != NULL) {
2721 		/* Nothing here. */
2722 	} else if (cp != NULL) {
2723 		struct g_mirror_disk *disk;
2724 
2725 		disk = cp->private;
2726 		if (disk == NULL)
2727 			return;
2728 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)disk->d_id);
2729 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2730 			sbuf_printf(sb, "%s<Synchronized>", indent);
2731 			if (disk->d_sync.ds_offset_done == 0)
2732 				sbuf_printf(sb, "0%%");
2733 			else {
2734 				sbuf_printf(sb, "%u%%",
2735 				    (u_int)((disk->d_sync.ds_offset_done * 100) /
2736 				    sc->sc_provider->mediasize));
2737 			}
2738 			sbuf_printf(sb, "</Synchronized>\n");
2739 		}
2740 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent,
2741 		    disk->d_sync.ds_syncid);
2742 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent,
2743 		    disk->d_genid);
2744 		sbuf_printf(sb, "%s<Flags>", indent);
2745 		if (disk->d_flags == 0)
2746 			sbuf_printf(sb, "NONE");
2747 		else {
2748 			int first = 1;
2749 
2750 #define	ADD_FLAG(flag, name)	do {					\
2751 	if ((disk->d_flags & (flag)) != 0) {				\
2752 		if (!first)						\
2753 			sbuf_printf(sb, ", ");				\
2754 		else							\
2755 			first = 0;					\
2756 		sbuf_printf(sb, name);					\
2757 	}								\
2758 } while (0)
2759 			ADD_FLAG(G_MIRROR_DISK_FLAG_DIRTY, "DIRTY");
2760 			ADD_FLAG(G_MIRROR_DISK_FLAG_HARDCODED, "HARDCODED");
2761 			ADD_FLAG(G_MIRROR_DISK_FLAG_INACTIVE, "INACTIVE");
2762 			ADD_FLAG(G_MIRROR_DISK_FLAG_SYNCHRONIZING,
2763 			    "SYNCHRONIZING");
2764 			ADD_FLAG(G_MIRROR_DISK_FLAG_FORCE_SYNC, "FORCE_SYNC");
2765 #undef	ADD_FLAG
2766 		}
2767 		sbuf_printf(sb, "</Flags>\n");
2768 		sbuf_printf(sb, "%s<Priority>%u</Priority>\n", indent,
2769 		    disk->d_priority);
2770 		sbuf_printf(sb, "%s<State>%s</State>\n", indent,
2771 		    g_mirror_disk_state2str(disk->d_state));
2772 	} else {
2773 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)sc->sc_id);
2774 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent, sc->sc_syncid);
2775 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent, sc->sc_genid);
2776 		sbuf_printf(sb, "%s<Flags>", indent);
2777 		if (sc->sc_flags == 0)
2778 			sbuf_printf(sb, "NONE");
2779 		else {
2780 			int first = 1;
2781 
2782 #define	ADD_FLAG(flag, name)	do {					\
2783 	if ((sc->sc_flags & (flag)) != 0) {				\
2784 		if (!first)						\
2785 			sbuf_printf(sb, ", ");				\
2786 		else							\
2787 			first = 0;					\
2788 		sbuf_printf(sb, name);					\
2789 	}								\
2790 } while (0)
2791 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOAUTOSYNC, "NOAUTOSYNC");
2792 #undef	ADD_FLAG
2793 		}
2794 		sbuf_printf(sb, "</Flags>\n");
2795 		sbuf_printf(sb, "%s<Slice>%u</Slice>\n", indent,
2796 		    (u_int)sc->sc_slice);
2797 		sbuf_printf(sb, "%s<Balance>%s</Balance>\n", indent,
2798 		    balance_name(sc->sc_balance));
2799 		sbuf_printf(sb, "%s<Components>%u</Components>\n", indent,
2800 		    sc->sc_ndisks);
2801 		sbuf_printf(sb, "%s<State>", indent);
2802 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
2803 			sbuf_printf(sb, "%s", "STARTING");
2804 		else if (sc->sc_ndisks ==
2805 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE))
2806 			sbuf_printf(sb, "%s", "COMPLETE");
2807 		else
2808 			sbuf_printf(sb, "%s", "DEGRADED");
2809 		sbuf_printf(sb, "</State>\n");
2810 	}
2811 }
2812 
2813 static void
2814 g_mirror_shutdown(void *arg, int howto)
2815 {
2816 	struct g_class *mp;
2817 	struct g_geom *gp, *gp2;
2818 
2819 	mp = arg;
2820 	DROP_GIANT();
2821 	g_topology_lock();
2822 	LIST_FOREACH_SAFE(gp, &mp->geom, geom, gp2) {
2823 		if (gp->softc == NULL)
2824 			continue;
2825 		g_mirror_destroy(gp->softc, 1);
2826 	}
2827 	g_topology_unlock();
2828 	PICKUP_GIANT();
2829 #if 0
2830 	tsleep(&gp, PRIBIO, "m:shutdown", hz * 20);
2831 #endif
2832 }
2833 
2834 static void
2835 g_mirror_init(struct g_class *mp)
2836 {
2837 
2838 	g_mirror_ehtag = EVENTHANDLER_REGISTER(shutdown_post_sync,
2839 	    g_mirror_shutdown, mp, SHUTDOWN_PRI_FIRST);
2840 	if (g_mirror_ehtag == NULL)
2841 		G_MIRROR_DEBUG(0, "Warning! Cannot register shutdown event.");
2842 }
2843 
2844 static void
2845 g_mirror_fini(struct g_class *mp)
2846 {
2847 
2848 	if (g_mirror_ehtag == NULL)
2849 		return;
2850 	EVENTHANDLER_DEREGISTER(shutdown_post_sync, g_mirror_ehtag);
2851 }
2852 
2853 static int
2854 g_mirror_can_go(void)
2855 {
2856 	struct g_mirror_softc *sc;
2857 	struct g_geom *gp;
2858 	struct g_provider *pp;
2859 	int can_go;
2860 
2861 	DROP_GIANT();
2862 	can_go = 1;
2863 	g_topology_lock();
2864 	LIST_FOREACH(gp, &g_mirror_class.geom, geom) {
2865 		sc = gp->softc;
2866 		if (sc == NULL) {
2867 			can_go = 0;
2868 			break;
2869 		}
2870 		pp = sc->sc_provider;
2871 		if (pp == NULL || pp->error != 0) {
2872 			can_go = 0;
2873 			break;
2874 		}
2875 	}
2876 	g_topology_unlock();
2877 	PICKUP_GIANT();
2878 	return (can_go);
2879 }
2880 
2881 static void
2882 g_mirror_rootwait(void)
2883 {
2884 
2885 	/*
2886 	 * HACK: Wait for GEOM, because g_mirror_rootwait() can be called,
2887 	 * HACK: before we get providers for tasting.
2888 	 */
2889 	tsleep(&g_mirror_class, PRIBIO, "mroot", hz * 3);
2890 	/*
2891 	 * Wait for mirrors in degraded state.
2892 	 */
2893 	for (;;) {
2894 		if (g_mirror_can_go())
2895 			break;
2896 		tsleep(&g_mirror_class, PRIBIO, "mroot", hz);
2897 	}
2898 }
2899 
2900 SYSINIT(g_mirror_root, SI_SUB_RAID, SI_ORDER_FIRST, g_mirror_rootwait, NULL)
2901 
2902 DECLARE_GEOM_CLASS(g_mirror_class, g_mirror);
2903