xref: /freebsd/sys/geom/mirror/g_mirror.c (revision ebccf1e3a6b11b97cbf5f813dd76636e892a9035)
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 	cbp = g_clone_bio(bp);
1217 	if (cbp == NULL) {
1218 		if (bp->bio_error == 0)
1219 			bp->bio_error = ENOMEM;
1220 		g_io_deliver(bp, bp->bio_error);
1221 		return;
1222 	}
1223 	/*
1224 	 * Fill in the component buf structure.
1225 	 */
1226 	cp = disk->d_consumer;
1227 	cbp->bio_done = g_mirror_done;
1228 	cbp->bio_to = cp->provider;
1229 	binuptime(&disk->d_last_used);
1230 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1231 	KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1232 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1233 	    cp->acw, cp->ace));
1234 	cp->index++;
1235 	g_io_request(cbp, cp);
1236 }
1237 
1238 static void
1239 g_mirror_request_split(struct g_mirror_softc *sc, struct bio *bp)
1240 {
1241 	struct bio_queue_head queue;
1242 	struct g_mirror_disk *disk;
1243 	struct g_consumer *cp;
1244 	struct bio *cbp;
1245 	off_t left, mod, offset, slice;
1246 	u_char *data;
1247 	u_int ndisks;
1248 
1249 	if (bp->bio_length <= sc->sc_slice) {
1250 		g_mirror_request_round_robin(sc, bp);
1251 		return;
1252 	}
1253 	ndisks = g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE);
1254 	slice = bp->bio_length / ndisks;
1255 	mod = slice % sc->sc_provider->sectorsize;
1256 	if (mod != 0)
1257 		slice += sc->sc_provider->sectorsize - mod;
1258 	/*
1259 	 * Allocate all bios before sending any request, so we can
1260 	 * return ENOMEM in nice and clean way.
1261 	 */
1262 	left = bp->bio_length;
1263 	offset = bp->bio_offset;
1264 	data = bp->bio_data;
1265 	bioq_init(&queue);
1266 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1267 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1268 			continue;
1269 		cbp = g_clone_bio(bp);
1270 		if (cbp == NULL) {
1271 			for (cbp = bioq_first(&queue); cbp != NULL;
1272 			    cbp = bioq_first(&queue)) {
1273 				bioq_remove(&queue, cbp);
1274 				g_destroy_bio(cbp);
1275 			}
1276 			if (bp->bio_error == 0)
1277 				bp->bio_error = ENOMEM;
1278 			g_io_deliver(bp, bp->bio_error);
1279 			return;
1280 		}
1281 		bioq_insert_tail(&queue, cbp);
1282 		cbp->bio_done = g_mirror_done;
1283 		cbp->bio_caller1 = disk;
1284 		cbp->bio_to = disk->d_consumer->provider;
1285 		cbp->bio_offset = offset;
1286 		cbp->bio_data = data;
1287 		cbp->bio_length = MIN(left, slice);
1288 		left -= cbp->bio_length;
1289 		if (left == 0)
1290 			break;
1291 		offset += cbp->bio_length;
1292 		data += cbp->bio_length;
1293 	}
1294 	for (cbp = bioq_first(&queue); cbp != NULL; cbp = bioq_first(&queue)) {
1295 		bioq_remove(&queue, cbp);
1296 		G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1297 		disk = cbp->bio_caller1;
1298 		cbp->bio_caller1 = NULL;
1299 		cp = disk->d_consumer;
1300 		KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1301 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1302 		    cp->acr, cp->acw, cp->ace));
1303 		disk->d_consumer->index++;
1304 		g_io_request(cbp, disk->d_consumer);
1305 	}
1306 }
1307 
1308 static void
1309 g_mirror_register_request(struct bio *bp)
1310 {
1311 	struct g_mirror_softc *sc;
1312 
1313 	sc = bp->bio_to->geom->softc;
1314 	switch (bp->bio_cmd) {
1315 	case BIO_READ:
1316 		switch (sc->sc_balance) {
1317 		case G_MIRROR_BALANCE_LOAD:
1318 			g_mirror_request_load(sc, bp);
1319 			break;
1320 		case G_MIRROR_BALANCE_PREFER:
1321 			g_mirror_request_prefer(sc, bp);
1322 			break;
1323 		case G_MIRROR_BALANCE_ROUND_ROBIN:
1324 			g_mirror_request_round_robin(sc, bp);
1325 			break;
1326 		case G_MIRROR_BALANCE_SPLIT:
1327 			g_mirror_request_split(sc, bp);
1328 			break;
1329 		}
1330 		return;
1331 	case BIO_WRITE:
1332 	case BIO_DELETE:
1333 	    {
1334 		struct g_mirror_disk *disk;
1335 		struct g_mirror_disk_sync *sync;
1336 		struct bio_queue_head queue;
1337 		struct g_consumer *cp;
1338 		struct bio *cbp;
1339 
1340 		if (sc->sc_idle)
1341 			g_mirror_unidle(sc);
1342 		/*
1343 		 * Allocate all bios before sending any request, so we can
1344 		 * return ENOMEM in nice and clean way.
1345 		 */
1346 		bioq_init(&queue);
1347 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1348 			sync = &disk->d_sync;
1349 			switch (disk->d_state) {
1350 			case G_MIRROR_DISK_STATE_ACTIVE:
1351 				break;
1352 			case G_MIRROR_DISK_STATE_SYNCHRONIZING:
1353 				if (bp->bio_offset >= sync->ds_offset)
1354 					continue;
1355 				else if (bp->bio_offset + bp->bio_length >
1356 				    sync->ds_offset_done &&
1357 				    (bp->bio_offset < sync->ds_resync ||
1358 				     sync->ds_resync == -1)) {
1359 					sync->ds_resync = bp->bio_offset -
1360 					    (bp->bio_offset % MAXPHYS);
1361 				}
1362 				break;
1363 			default:
1364 				continue;
1365 			}
1366 			cbp = g_clone_bio(bp);
1367 			if (cbp == NULL) {
1368 				for (cbp = bioq_first(&queue); cbp != NULL;
1369 				    cbp = bioq_first(&queue)) {
1370 					bioq_remove(&queue, cbp);
1371 					g_destroy_bio(cbp);
1372 				}
1373 				if (bp->bio_error == 0)
1374 					bp->bio_error = ENOMEM;
1375 				g_io_deliver(bp, bp->bio_error);
1376 				return;
1377 			}
1378 			bioq_insert_tail(&queue, cbp);
1379 			cbp->bio_done = g_mirror_done;
1380 			cp = disk->d_consumer;
1381 			cbp->bio_caller1 = cp;
1382 			cbp->bio_to = cp->provider;
1383 			KASSERT(cp->acr == 1 && cp->acw == 1 && cp->ace == 1,
1384 			    ("Consumer %s not opened (r%dw%de%d).",
1385 			    cp->provider->name, cp->acr, cp->acw, cp->ace));
1386 		}
1387 		for (cbp = bioq_first(&queue); cbp != NULL;
1388 		    cbp = bioq_first(&queue)) {
1389 			bioq_remove(&queue, cbp);
1390 			G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1391 			cp = cbp->bio_caller1;
1392 			cbp->bio_caller1 = NULL;
1393 			cp->index++;
1394 			g_io_request(cbp, cp);
1395 		}
1396 		/*
1397 		 * Bump syncid on first write.
1398 		 */
1399 		if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0) {
1400 			sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
1401 			g_topology_lock();
1402 			g_mirror_bump_syncid(sc);
1403 			g_topology_unlock();
1404 		}
1405 		return;
1406 	    }
1407 	default:
1408 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1409 		    bp->bio_cmd, sc->sc_name));
1410 		break;
1411 	}
1412 }
1413 
1414 static int
1415 g_mirror_can_destroy(struct g_mirror_softc *sc)
1416 {
1417 	struct g_geom *gp;
1418 	struct g_consumer *cp;
1419 
1420 	g_topology_assert();
1421 	gp = sc->sc_geom;
1422 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1423 		if (g_mirror_is_busy(sc, cp))
1424 			return (0);
1425 	}
1426 	gp = sc->sc_sync.ds_geom;
1427 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1428 		if (g_mirror_is_busy(sc, cp))
1429 			return (0);
1430 	}
1431 	G_MIRROR_DEBUG(2, "No I/O requests for %s, it can be destroyed.",
1432 	    sc->sc_name);
1433 	return (1);
1434 }
1435 
1436 static int
1437 g_mirror_try_destroy(struct g_mirror_softc *sc)
1438 {
1439 
1440 	g_topology_lock();
1441 	if (!g_mirror_can_destroy(sc)) {
1442 		g_topology_unlock();
1443 		return (0);
1444 	}
1445 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_WAIT) != 0) {
1446 		g_topology_unlock();
1447 		G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1448 		    &sc->sc_worker);
1449 		wakeup(&sc->sc_worker);
1450 		sc->sc_worker = NULL;
1451 	} else {
1452 		g_mirror_destroy_device(sc);
1453 		g_topology_unlock();
1454 		free(sc, M_MIRROR);
1455 	}
1456 	return (1);
1457 }
1458 
1459 /*
1460  * Worker thread.
1461  */
1462 static void
1463 g_mirror_worker(void *arg)
1464 {
1465 	struct g_mirror_softc *sc;
1466 	struct g_mirror_disk *disk;
1467 	struct g_mirror_disk_sync *sync;
1468 	struct g_mirror_event *ep;
1469 	struct bio *bp;
1470 	u_int nreqs;
1471 
1472 	sc = arg;
1473 	mtx_lock_spin(&sched_lock);
1474 	sched_prio(curthread, PRIBIO);
1475 	mtx_unlock_spin(&sched_lock);
1476 
1477 	nreqs = 0;
1478 	for (;;) {
1479 		G_MIRROR_DEBUG(5, "%s: Let's see...", __func__);
1480 		/*
1481 		 * First take a look at events.
1482 		 * This is important to handle events before any I/O requests.
1483 		 */
1484 		ep = g_mirror_event_get(sc);
1485 		if (ep != NULL && g_topology_try_lock()) {
1486 			g_mirror_event_remove(sc, ep);
1487 			if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0) {
1488 				/* Update only device status. */
1489 				G_MIRROR_DEBUG(3,
1490 				    "Running event for device %s.",
1491 				    sc->sc_name);
1492 				ep->e_error = 0;
1493 				g_mirror_update_device(sc, 1);
1494 			} else {
1495 				/* Update disk status. */
1496 				G_MIRROR_DEBUG(3, "Running event for disk %s.",
1497 				     g_mirror_get_diskname(ep->e_disk));
1498 				ep->e_error = g_mirror_update_disk(ep->e_disk,
1499 				    ep->e_state);
1500 				if (ep->e_error == 0)
1501 					g_mirror_update_device(sc, 0);
1502 			}
1503 			g_topology_unlock();
1504 			if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0) {
1505 				KASSERT(ep->e_error == 0,
1506 				    ("Error cannot be handled."));
1507 				g_mirror_event_free(ep);
1508 			} else {
1509 				ep->e_flags |= G_MIRROR_EVENT_DONE;
1510 				G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1511 				    ep);
1512 				mtx_lock(&sc->sc_events_mtx);
1513 				wakeup(ep);
1514 				mtx_unlock(&sc->sc_events_mtx);
1515 			}
1516 			if ((sc->sc_flags &
1517 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1518 				if (g_mirror_try_destroy(sc))
1519 					kthread_exit(0);
1520 			}
1521 			G_MIRROR_DEBUG(5, "%s: I'm here 1.", __func__);
1522 			continue;
1523 		}
1524 		/*
1525 		 * Now I/O requests.
1526 		 */
1527 		/* Get first request from the queue. */
1528 		mtx_lock(&sc->sc_queue_mtx);
1529 		bp = bioq_first(&sc->sc_queue);
1530 		if (bp == NULL) {
1531 			if (ep != NULL) {
1532 				/*
1533 				 * No I/O requests and topology lock was
1534 				 * already held? Try again.
1535 				 */
1536 				mtx_unlock(&sc->sc_queue_mtx);
1537 				continue;
1538 			}
1539 			if ((sc->sc_flags &
1540 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1541 				mtx_unlock(&sc->sc_queue_mtx);
1542 				if (g_mirror_try_destroy(sc))
1543 					kthread_exit(0);
1544 				mtx_lock(&sc->sc_queue_mtx);
1545 			}
1546 		}
1547 		if (sc->sc_sync.ds_ndisks > 0 &&
1548 		    (bp == NULL || nreqs > g_mirror_reqs_per_sync)) {
1549 			mtx_unlock(&sc->sc_queue_mtx);
1550 			/*
1551 			 * It is time for synchronization...
1552 			 */
1553 			nreqs = 0;
1554 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1555 				if (disk->d_state !=
1556 				    G_MIRROR_DISK_STATE_SYNCHRONIZING) {
1557 					continue;
1558 				}
1559 				sync = &disk->d_sync;
1560 				if (sync->ds_offset >=
1561 				    sc->sc_provider->mediasize) {
1562 					continue;
1563 				}
1564 				if (sync->ds_offset > sync->ds_offset_done)
1565 					continue;
1566 				if (sync->ds_resync != -1) {
1567 					sync->ds_offset = sync->ds_resync;
1568 					sync->ds_offset_done = sync->ds_resync;
1569 					sync->ds_resync = -1;
1570 				}
1571 				g_mirror_sync_one(disk);
1572 			}
1573 			G_MIRROR_DEBUG(5, "%s: I'm here 2.", __func__);
1574 			goto sleep;
1575 		}
1576 		if (bp == NULL) {
1577 			if (g_mirror_check_idle(sc)) {
1578 				u_int idletime;
1579 
1580 				idletime = g_mirror_idletime;
1581 				if (idletime == 0)
1582 					idletime = 1;
1583 				idletime *= hz;
1584 				if (msleep(sc, &sc->sc_queue_mtx, PRIBIO | PDROP,
1585 				    "m:w1", idletime) == EWOULDBLOCK) {
1586 					G_MIRROR_DEBUG(5, "%s: I'm here 3.",
1587 					    __func__);
1588 					/*
1589 					 * No I/O requests in 'idletime' seconds,
1590 					 * so mark components as clean.
1591 					 */
1592 					g_mirror_idle(sc);
1593 				}
1594 				G_MIRROR_DEBUG(5, "%s: I'm here 4.", __func__);
1595 			} else {
1596 				MSLEEP(sc, &sc->sc_queue_mtx, PRIBIO | PDROP,
1597 				    "m:w2", 0);
1598 				G_MIRROR_DEBUG(5, "%s: I'm here 5.", __func__);
1599 			}
1600 			continue;
1601 		}
1602 		nreqs++;
1603 		bioq_remove(&sc->sc_queue, bp);
1604 		mtx_unlock(&sc->sc_queue_mtx);
1605 
1606 		if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_REGULAR) != 0) {
1607 			g_mirror_regular_request(bp);
1608 		} else if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0) {
1609 			u_int timeout, sps;
1610 
1611 			g_mirror_sync_request(bp);
1612 sleep:
1613 			sps = g_mirror_syncs_per_sec;
1614 			if (sps == 0) {
1615 				G_MIRROR_DEBUG(5, "%s: I'm here 6.", __func__);
1616 				continue;
1617 			}
1618 			if (ep != NULL) {
1619 				/*
1620 				 * We have some pending events, don't sleep now.
1621 				 */
1622 				G_MIRROR_DEBUG(5, "%s: I'm here 7.", __func__);
1623 				continue;
1624 			}
1625 			mtx_lock(&sc->sc_queue_mtx);
1626 			if (bioq_first(&sc->sc_queue) != NULL) {
1627 				mtx_unlock(&sc->sc_queue_mtx);
1628 				G_MIRROR_DEBUG(5, "%s: I'm here 8.", __func__);
1629 				continue;
1630 			}
1631 			timeout = hz / sps;
1632 			if (timeout == 0)
1633 				timeout = 1;
1634 			MSLEEP(sc, &sc->sc_queue_mtx, PRIBIO | PDROP, "m:w3",
1635 			    timeout);
1636 		} else {
1637 			g_mirror_register_request(bp);
1638 		}
1639 		G_MIRROR_DEBUG(5, "%s: I'm here 9.", __func__);
1640 	}
1641 }
1642 
1643 /*
1644  * Open disk's consumer if needed.
1645  */
1646 static void
1647 g_mirror_update_access(struct g_mirror_disk *disk)
1648 {
1649 	struct g_provider *pp;
1650 
1651 	g_topology_assert();
1652 
1653 	pp = disk->d_softc->sc_provider;
1654 	if (pp == NULL)
1655 		return;
1656 	if (pp->acw > 0) {
1657 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) == 0) {
1658 			G_MIRROR_DEBUG(1,
1659 			    "Disk %s (device %s) marked as dirty.",
1660 			    g_mirror_get_diskname(disk),
1661 			    disk->d_softc->sc_name);
1662 			disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1663 		}
1664 	} else if (pp->acw == 0) {
1665 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
1666 			G_MIRROR_DEBUG(1,
1667 			    "Disk %s (device %s) marked as clean.",
1668 			    g_mirror_get_diskname(disk),
1669 			    disk->d_softc->sc_name);
1670 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
1671 		}
1672 	}
1673 }
1674 
1675 static void
1676 g_mirror_sync_start(struct g_mirror_disk *disk)
1677 {
1678 	struct g_mirror_softc *sc;
1679 	int error;
1680 
1681 	g_topology_assert();
1682 
1683 	sc = disk->d_softc;
1684 	KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
1685 	    ("Device not in RUNNING state (%s, %u).", sc->sc_name,
1686 	    sc->sc_state));
1687 
1688 	G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s.", sc->sc_name,
1689 	    g_mirror_get_diskname(disk));
1690 	disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1691 	KASSERT(disk->d_sync.ds_consumer == NULL,
1692 	    ("Sync consumer already exists (device=%s, disk=%s).",
1693 	    sc->sc_name, g_mirror_get_diskname(disk)));
1694 	disk->d_sync.ds_consumer = g_new_consumer(sc->sc_sync.ds_geom);
1695 	disk->d_sync.ds_consumer->private = disk;
1696 	disk->d_sync.ds_consumer->index = 0;
1697 	error = g_attach(disk->d_sync.ds_consumer, disk->d_softc->sc_provider);
1698 	KASSERT(error == 0, ("Cannot attach to %s (error=%d).",
1699 	    disk->d_softc->sc_name, error));
1700 	error = g_access(disk->d_sync.ds_consumer, 1, 0, 0);
1701 	KASSERT(error == 0, ("Cannot open %s (error=%d).",
1702 	    disk->d_softc->sc_name, error));
1703 	disk->d_sync.ds_data = malloc(MAXPHYS, M_MIRROR, M_WAITOK);
1704 	sc->sc_sync.ds_ndisks++;
1705 }
1706 
1707 /*
1708  * Stop synchronization process.
1709  * type: 0 - synchronization finished
1710  *       1 - synchronization stopped
1711  */
1712 static void
1713 g_mirror_sync_stop(struct g_mirror_disk *disk, int type)
1714 {
1715 
1716 	g_topology_assert();
1717 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
1718 	    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
1719 	    g_mirror_disk_state2str(disk->d_state)));
1720 	if (disk->d_sync.ds_consumer == NULL)
1721 		return;
1722 
1723 	if (type == 0) {
1724 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s finished.",
1725 		    disk->d_softc->sc_name, g_mirror_get_diskname(disk));
1726 	} else /* if (type == 1) */ {
1727 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s stopped.",
1728 		    disk->d_softc->sc_name, g_mirror_get_diskname(disk));
1729 	}
1730 	g_mirror_kill_consumer(disk->d_softc, disk->d_sync.ds_consumer);
1731 	free(disk->d_sync.ds_data, M_MIRROR);
1732 	disk->d_sync.ds_consumer = NULL;
1733 	disk->d_softc->sc_sync.ds_ndisks--;
1734 	disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
1735 }
1736 
1737 static void
1738 g_mirror_launch_provider(struct g_mirror_softc *sc)
1739 {
1740 	struct g_mirror_disk *disk;
1741 	struct g_provider *pp;
1742 
1743 	g_topology_assert();
1744 
1745 	pp = g_new_providerf(sc->sc_geom, "mirror/%s", sc->sc_name);
1746 	pp->mediasize = sc->sc_mediasize;
1747 	pp->sectorsize = sc->sc_sectorsize;
1748 	sc->sc_provider = pp;
1749 	g_error_provider(pp, 0);
1750 	G_MIRROR_DEBUG(0, "Device %s: provider %s launched.", sc->sc_name,
1751 	    pp->name);
1752 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1753 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
1754 			g_mirror_sync_start(disk);
1755 	}
1756 }
1757 
1758 static void
1759 g_mirror_destroy_provider(struct g_mirror_softc *sc)
1760 {
1761 	struct g_mirror_disk *disk;
1762 	struct bio *bp;
1763 
1764 	g_topology_assert();
1765 	KASSERT(sc->sc_provider != NULL, ("NULL provider (device=%s).",
1766 	    sc->sc_name));
1767 
1768 	g_error_provider(sc->sc_provider, ENXIO);
1769 	mtx_lock(&sc->sc_queue_mtx);
1770 	while ((bp = bioq_first(&sc->sc_queue)) != NULL) {
1771 		bioq_remove(&sc->sc_queue, bp);
1772 		g_io_deliver(bp, ENXIO);
1773 	}
1774 	mtx_unlock(&sc->sc_queue_mtx);
1775 	G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.", sc->sc_name,
1776 	    sc->sc_provider->name);
1777 	sc->sc_provider->flags |= G_PF_WITHER;
1778 	g_orphan_provider(sc->sc_provider, ENXIO);
1779 	sc->sc_provider = NULL;
1780 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1781 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
1782 			g_mirror_sync_stop(disk, 1);
1783 	}
1784 }
1785 
1786 static void
1787 g_mirror_go(void *arg)
1788 {
1789 	struct g_mirror_softc *sc;
1790 
1791 	sc = arg;
1792 	G_MIRROR_DEBUG(0, "Force device %s start due to timeout.", sc->sc_name);
1793 	g_mirror_event_send(sc, 0,
1794 	    G_MIRROR_EVENT_DONTWAIT | G_MIRROR_EVENT_DEVICE);
1795 }
1796 
1797 static u_int
1798 g_mirror_determine_state(struct g_mirror_disk *disk)
1799 {
1800 	struct g_mirror_softc *sc;
1801 	u_int state;
1802 
1803 	sc = disk->d_softc;
1804 	if (sc->sc_syncid == disk->d_sync.ds_syncid) {
1805 		if ((disk->d_flags &
1806 		    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
1807 			/* Disk does not need synchronization. */
1808 			state = G_MIRROR_DISK_STATE_ACTIVE;
1809 		} else {
1810 			if ((sc->sc_flags &
1811 			     G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0  ||
1812 			    (disk->d_flags &
1813 			     G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
1814 				/*
1815 				 * We can start synchronization from
1816 				 * the stored offset.
1817 				 */
1818 				state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
1819 			} else {
1820 				state = G_MIRROR_DISK_STATE_STALE;
1821 			}
1822 		}
1823 	} else if (disk->d_sync.ds_syncid < sc->sc_syncid) {
1824 		/*
1825 		 * Reset all synchronization data for this disk,
1826 		 * because if it even was synchronized, it was
1827 		 * synchronized to disks with different syncid.
1828 		 */
1829 		disk->d_flags |= G_MIRROR_DISK_FLAG_SYNCHRONIZING;
1830 		disk->d_sync.ds_offset = 0;
1831 		disk->d_sync.ds_offset_done = 0;
1832 		disk->d_sync.ds_syncid = sc->sc_syncid;
1833 		if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
1834 		    (disk->d_flags & G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
1835 			state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
1836 		} else {
1837 			state = G_MIRROR_DISK_STATE_STALE;
1838 		}
1839 	} else /* if (sc->sc_syncid < disk->d_sync.ds_syncid) */ {
1840 		/*
1841 		 * Not good, NOT GOOD!
1842 		 * It means that mirror was started on stale disks
1843 		 * and more fresh disk just arrive.
1844 		 * If there were writes, mirror is fucked up, sorry.
1845 		 * I think the best choice here is don't touch
1846 		 * this disk and inform the user laudly.
1847 		 */
1848 		G_MIRROR_DEBUG(0, "Device %s was started before the freshest "
1849 		    "disk (%s) arrives!! It will not be connected to the "
1850 		    "running device.", sc->sc_name,
1851 		    g_mirror_get_diskname(disk));
1852 		g_mirror_destroy_disk(disk);
1853 		state = G_MIRROR_DISK_STATE_NONE;
1854 		/* Return immediately, because disk was destroyed. */
1855 		return (state);
1856 	}
1857 	G_MIRROR_DEBUG(3, "State for %s disk: %s.",
1858 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(state));
1859 	return (state);
1860 }
1861 
1862 /*
1863  * Update device state.
1864  */
1865 static void
1866 g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force)
1867 {
1868 	struct g_mirror_disk *disk;
1869 	u_int state;
1870 
1871 	g_topology_assert();
1872 
1873 	switch (sc->sc_state) {
1874 	case G_MIRROR_DEVICE_STATE_STARTING:
1875 	    {
1876 		struct g_mirror_disk *pdisk, *tdisk;
1877 		u_int dirty, ndisks, genid, syncid;
1878 
1879 		KASSERT(sc->sc_provider == NULL,
1880 		    ("Non-NULL provider in STARTING state (%s).", sc->sc_name));
1881 		/*
1882 		 * Are we ready? We are, if all disks are connected or
1883 		 * if we have any disks and 'force' is true.
1884 		 */
1885 		if ((force && g_mirror_ndisks(sc, -1) > 0) ||
1886 		    sc->sc_ndisks == g_mirror_ndisks(sc, -1)) {
1887 			;
1888 		} else if (g_mirror_ndisks(sc, -1) == 0) {
1889 			/*
1890 			 * Disks went down in starting phase, so destroy
1891 			 * device.
1892 			 */
1893 			callout_drain(&sc->sc_callout);
1894 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
1895 			return;
1896 		} else {
1897 			return;
1898 		}
1899 
1900 		/*
1901 		 * Activate all disks with the biggest syncid.
1902 		 */
1903 		if (force) {
1904 			/*
1905 			 * If 'force' is true, we have been called due to
1906 			 * timeout, so don't bother canceling timeout.
1907 			 */
1908 			ndisks = 0;
1909 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1910 				if ((disk->d_flags &
1911 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
1912 					ndisks++;
1913 				}
1914 			}
1915 			if (ndisks == 0) {
1916 				/* No valid disks found, destroy device. */
1917 				sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
1918 				return;
1919 			}
1920 		} else {
1921 			/* Cancel timeout. */
1922 			callout_drain(&sc->sc_callout);
1923 		}
1924 
1925 		/*
1926 		 * Find the biggest genid.
1927 		 */
1928 		genid = 0;
1929 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1930 			if (disk->d_genid > genid)
1931 				genid = disk->d_genid;
1932 		}
1933 		sc->sc_genid = genid;
1934 		/*
1935 		 * Remove all disks without the biggest genid.
1936 		 */
1937 		LIST_FOREACH_SAFE(disk, &sc->sc_disks, d_next, tdisk) {
1938 			if (disk->d_genid < genid) {
1939 				G_MIRROR_DEBUG(0,
1940 				    "Component %s (device %s) broken, skipping.",
1941 				    g_mirror_get_diskname(disk), sc->sc_name);
1942 				g_mirror_destroy_disk(disk);
1943 			}
1944 		}
1945 
1946 		/*
1947 		 * Find the biggest syncid.
1948 		 */
1949 		syncid = 0;
1950 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1951 			if (disk->d_sync.ds_syncid > syncid)
1952 				syncid = disk->d_sync.ds_syncid;
1953 		}
1954 
1955 		/*
1956 		 * Here we need to look for dirty disks and if all disks
1957 		 * with the biggest syncid are dirty, we have to choose
1958 		 * one with the biggest priority and rebuild the rest.
1959 		 */
1960 		/*
1961 		 * Find the number of dirty disks with the biggest syncid.
1962 		 * Find the number of disks with the biggest syncid.
1963 		 * While here, find a disk with the biggest priority.
1964 		 */
1965 		dirty = ndisks = 0;
1966 		pdisk = NULL;
1967 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1968 			if (disk->d_sync.ds_syncid != syncid)
1969 				continue;
1970 			if ((disk->d_flags &
1971 			    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
1972 				continue;
1973 			}
1974 			ndisks++;
1975 			if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
1976 				dirty++;
1977 				if (pdisk == NULL ||
1978 				    pdisk->d_priority < disk->d_priority) {
1979 					pdisk = disk;
1980 				}
1981 			}
1982 		}
1983 		if (dirty == 0) {
1984 			/* No dirty disks at all, great. */
1985 		} else if (dirty == ndisks) {
1986 			/*
1987 			 * Force synchronization for all dirty disks except one
1988 			 * with the biggest priority.
1989 			 */
1990 			KASSERT(pdisk != NULL, ("pdisk == NULL"));
1991 			G_MIRROR_DEBUG(1, "Using disk %s (device %s) as a "
1992 			    "master disk for synchronization.",
1993 			    g_mirror_get_diskname(pdisk), sc->sc_name);
1994 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1995 				if (disk->d_sync.ds_syncid != syncid)
1996 					continue;
1997 				if ((disk->d_flags &
1998 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
1999 					continue;
2000 				}
2001 				KASSERT((disk->d_flags &
2002 				    G_MIRROR_DISK_FLAG_DIRTY) != 0,
2003 				    ("Disk %s isn't marked as dirty.",
2004 				    g_mirror_get_diskname(disk)));
2005 				/* Skip the disk with the biggest priority. */
2006 				if (disk == pdisk)
2007 					continue;
2008 				disk->d_sync.ds_syncid = 0;
2009 			}
2010 		} else if (dirty < ndisks) {
2011 			/*
2012 			 * Force synchronization for all dirty disks.
2013 			 * We have some non-dirty disks.
2014 			 */
2015 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2016 				if (disk->d_sync.ds_syncid != syncid)
2017 					continue;
2018 				if ((disk->d_flags &
2019 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2020 					continue;
2021 				}
2022 				if ((disk->d_flags &
2023 				    G_MIRROR_DISK_FLAG_DIRTY) == 0) {
2024 					continue;
2025 				}
2026 				disk->d_sync.ds_syncid = 0;
2027 			}
2028 		}
2029 
2030 		/* Reset hint. */
2031 		sc->sc_hint = NULL;
2032 		sc->sc_syncid = syncid;
2033 		if (force) {
2034 			/* Remember to bump syncid on first write. */
2035 			sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2036 		}
2037 		state = G_MIRROR_DEVICE_STATE_RUNNING;
2038 		G_MIRROR_DEBUG(1, "Device %s state changed from %s to %s.",
2039 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state),
2040 		    g_mirror_device_state2str(state));
2041 		sc->sc_state = state;
2042 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2043 			state = g_mirror_determine_state(disk);
2044 			g_mirror_event_send(disk, state,
2045 			    G_MIRROR_EVENT_DONTWAIT);
2046 			if (state == G_MIRROR_DISK_STATE_STALE)
2047 				sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2048 		}
2049 		wakeup(&g_mirror_class);
2050 		break;
2051 	    }
2052 	case G_MIRROR_DEVICE_STATE_RUNNING:
2053 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 0 &&
2054 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2055 			/*
2056 			 * No active disks or no disks at all,
2057 			 * so destroy device.
2058 			 */
2059 			if (sc->sc_provider != NULL)
2060 				g_mirror_destroy_provider(sc);
2061 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2062 			break;
2063 		} else if (g_mirror_ndisks(sc,
2064 		    G_MIRROR_DISK_STATE_ACTIVE) > 0 &&
2065 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2066 			/*
2067 			 * We have active disks, launch provider if it doesn't
2068 			 * exist.
2069 			 */
2070 			if (sc->sc_provider == NULL)
2071 				g_mirror_launch_provider(sc);
2072 		}
2073 		/*
2074 		 * Genid should be bumped immediately, so do it here.
2075 		 */
2076 		if ((sc->sc_bump_id & G_MIRROR_BUMP_GENID) != 0) {
2077 			sc->sc_bump_id &= ~G_MIRROR_BUMP_GENID;
2078 			g_mirror_bump_genid(sc);
2079 		}
2080 		break;
2081 	default:
2082 		KASSERT(1 == 0, ("Wrong device state (%s, %s).",
2083 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state)));
2084 		break;
2085 	}
2086 }
2087 
2088 /*
2089  * Update disk state and device state if needed.
2090  */
2091 #define	DISK_STATE_CHANGED()	G_MIRROR_DEBUG(1,			\
2092 	"Disk %s state changed from %s to %s (device %s).",		\
2093 	g_mirror_get_diskname(disk),					\
2094 	g_mirror_disk_state2str(disk->d_state),				\
2095 	g_mirror_disk_state2str(state), sc->sc_name)
2096 static int
2097 g_mirror_update_disk(struct g_mirror_disk *disk, u_int state)
2098 {
2099 	struct g_mirror_softc *sc;
2100 
2101 	g_topology_assert();
2102 
2103 	sc = disk->d_softc;
2104 again:
2105 	G_MIRROR_DEBUG(3, "Changing disk %s state from %s to %s.",
2106 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(disk->d_state),
2107 	    g_mirror_disk_state2str(state));
2108 	switch (state) {
2109 	case G_MIRROR_DISK_STATE_NEW:
2110 		/*
2111 		 * Possible scenarios:
2112 		 * 1. New disk arrive.
2113 		 */
2114 		/* Previous state should be NONE. */
2115 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NONE,
2116 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2117 		    g_mirror_disk_state2str(disk->d_state)));
2118 		DISK_STATE_CHANGED();
2119 
2120 		disk->d_state = state;
2121 		if (LIST_EMPTY(&sc->sc_disks))
2122 			LIST_INSERT_HEAD(&sc->sc_disks, disk, d_next);
2123 		else {
2124 			struct g_mirror_disk *dp;
2125 
2126 			LIST_FOREACH(dp, &sc->sc_disks, d_next) {
2127 				if (disk->d_priority >= dp->d_priority) {
2128 					LIST_INSERT_BEFORE(dp, disk, d_next);
2129 					dp = NULL;
2130 					break;
2131 				}
2132 				if (LIST_NEXT(dp, d_next) == NULL)
2133 					break;
2134 			}
2135 			if (dp != NULL)
2136 				LIST_INSERT_AFTER(dp, disk, d_next);
2137 		}
2138 		G_MIRROR_DEBUG(0, "Device %s: provider %s detected.",
2139 		    sc->sc_name, g_mirror_get_diskname(disk));
2140 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
2141 			break;
2142 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2143 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2144 		    g_mirror_device_state2str(sc->sc_state),
2145 		    g_mirror_get_diskname(disk),
2146 		    g_mirror_disk_state2str(disk->d_state)));
2147 		state = g_mirror_determine_state(disk);
2148 		if (state != G_MIRROR_DISK_STATE_NONE)
2149 			goto again;
2150 		break;
2151 	case G_MIRROR_DISK_STATE_ACTIVE:
2152 		/*
2153 		 * Possible scenarios:
2154 		 * 1. New disk does not need synchronization.
2155 		 * 2. Synchronization process finished successfully.
2156 		 */
2157 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2158 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2159 		    g_mirror_device_state2str(sc->sc_state),
2160 		    g_mirror_get_diskname(disk),
2161 		    g_mirror_disk_state2str(disk->d_state)));
2162 		/* Previous state should be NEW or SYNCHRONIZING. */
2163 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW ||
2164 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2165 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2166 		    g_mirror_disk_state2str(disk->d_state)));
2167 		DISK_STATE_CHANGED();
2168 
2169 		if (disk->d_state == G_MIRROR_DISK_STATE_NEW)
2170 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2171 		else if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2172 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2173 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_FORCE_SYNC;
2174 			g_mirror_sync_stop(disk, 0);
2175 		}
2176 		disk->d_state = state;
2177 		disk->d_sync.ds_offset = 0;
2178 		disk->d_sync.ds_offset_done = 0;
2179 		g_mirror_update_access(disk);
2180 		g_mirror_update_metadata(disk);
2181 		G_MIRROR_DEBUG(0, "Device %s: provider %s activated.",
2182 		    sc->sc_name, g_mirror_get_diskname(disk));
2183 		break;
2184 	case G_MIRROR_DISK_STATE_STALE:
2185 		/*
2186 		 * Possible scenarios:
2187 		 * 1. Stale disk was connected.
2188 		 */
2189 		/* Previous state should be NEW. */
2190 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2191 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2192 		    g_mirror_disk_state2str(disk->d_state)));
2193 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2194 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2195 		    g_mirror_device_state2str(sc->sc_state),
2196 		    g_mirror_get_diskname(disk),
2197 		    g_mirror_disk_state2str(disk->d_state)));
2198 		/*
2199 		 * STALE state is only possible if device is marked
2200 		 * NOAUTOSYNC.
2201 		 */
2202 		KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) != 0,
2203 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2204 		    g_mirror_device_state2str(sc->sc_state),
2205 		    g_mirror_get_diskname(disk),
2206 		    g_mirror_disk_state2str(disk->d_state)));
2207 		DISK_STATE_CHANGED();
2208 
2209 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2210 		disk->d_state = state;
2211 		g_mirror_update_metadata(disk);
2212 		G_MIRROR_DEBUG(0, "Device %s: provider %s is stale.",
2213 		    sc->sc_name, g_mirror_get_diskname(disk));
2214 		break;
2215 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
2216 		/*
2217 		 * Possible scenarios:
2218 		 * 1. Disk which needs synchronization was connected.
2219 		 */
2220 		/* Previous state should be NEW. */
2221 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2222 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2223 		    g_mirror_disk_state2str(disk->d_state)));
2224 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2225 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2226 		    g_mirror_device_state2str(sc->sc_state),
2227 		    g_mirror_get_diskname(disk),
2228 		    g_mirror_disk_state2str(disk->d_state)));
2229 		DISK_STATE_CHANGED();
2230 
2231 		if (disk->d_state == G_MIRROR_DISK_STATE_NEW)
2232 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2233 		disk->d_state = state;
2234 		if (sc->sc_provider != NULL) {
2235 			g_mirror_sync_start(disk);
2236 			g_mirror_update_metadata(disk);
2237 		}
2238 		break;
2239 	case G_MIRROR_DISK_STATE_DISCONNECTED:
2240 		/*
2241 		 * Possible scenarios:
2242 		 * 1. Device wasn't running yet, but disk disappear.
2243 		 * 2. Disk was active and disapppear.
2244 		 * 3. Disk disappear during synchronization process.
2245 		 */
2246 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING) {
2247 			/*
2248 			 * Previous state should be ACTIVE, STALE or
2249 			 * SYNCHRONIZING.
2250 			 */
2251 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
2252 			    disk->d_state == G_MIRROR_DISK_STATE_STALE ||
2253 			    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2254 			    ("Wrong disk state (%s, %s).",
2255 			    g_mirror_get_diskname(disk),
2256 			    g_mirror_disk_state2str(disk->d_state)));
2257 		} else if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING) {
2258 			/* Previous state should be NEW. */
2259 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2260 			    ("Wrong disk state (%s, %s).",
2261 			    g_mirror_get_diskname(disk),
2262 			    g_mirror_disk_state2str(disk->d_state)));
2263 			/*
2264 			 * Reset bumping syncid if disk disappeared in STARTING
2265 			 * state.
2266 			 */
2267 			if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0)
2268 				sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
2269 #ifdef	INVARIANTS
2270 		} else {
2271 			KASSERT(1 == 0, ("Wrong device state (%s, %s, %s, %s).",
2272 			    sc->sc_name,
2273 			    g_mirror_device_state2str(sc->sc_state),
2274 			    g_mirror_get_diskname(disk),
2275 			    g_mirror_disk_state2str(disk->d_state)));
2276 #endif
2277 		}
2278 		DISK_STATE_CHANGED();
2279 		G_MIRROR_DEBUG(0, "Device %s: provider %s disconnected.",
2280 		    sc->sc_name, g_mirror_get_diskname(disk));
2281 
2282 		g_mirror_destroy_disk(disk);
2283 		break;
2284 	case G_MIRROR_DISK_STATE_DESTROY:
2285 	    {
2286 		int error;
2287 
2288 		error = g_mirror_clear_metadata(disk);
2289 		if (error != 0)
2290 			return (error);
2291 		DISK_STATE_CHANGED();
2292 		G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.",
2293 		    sc->sc_name, g_mirror_get_diskname(disk));
2294 
2295 		g_mirror_destroy_disk(disk);
2296 		sc->sc_ndisks--;
2297 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2298 			g_mirror_update_metadata(disk);
2299 		}
2300 		break;
2301 	    }
2302 	default:
2303 		KASSERT(1 == 0, ("Unknown state (%u).", state));
2304 		break;
2305 	}
2306 	return (0);
2307 }
2308 #undef	DISK_STATE_CHANGED
2309 
2310 int
2311 g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md)
2312 {
2313 	struct g_provider *pp;
2314 	u_char *buf;
2315 	int error;
2316 
2317 	g_topology_assert();
2318 
2319 	error = g_access(cp, 1, 0, 0);
2320 	if (error != 0)
2321 		return (error);
2322 	pp = cp->provider;
2323 	g_topology_unlock();
2324 	/* Metadata are stored on last sector. */
2325 	buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
2326 	    &error);
2327 	g_topology_lock();
2328 	g_access(cp, -1, 0, 0);
2329 	if (error != 0) {
2330 		G_MIRROR_DEBUG(1, "Cannot read metadata from %s (error=%d).",
2331 		    cp->provider->name, error);
2332 		if (buf != NULL)
2333 			g_free(buf);
2334 		return (error);
2335 	}
2336 
2337 	/* Decode metadata. */
2338 	error = mirror_metadata_decode(buf, md);
2339 	g_free(buf);
2340 	if (strcmp(md->md_magic, G_MIRROR_MAGIC) != 0)
2341 		return (EINVAL);
2342 	if (md->md_version > G_MIRROR_VERSION) {
2343 		G_MIRROR_DEBUG(0,
2344 		    "Kernel module is too old to handle metadata from %s.",
2345 		    cp->provider->name);
2346 		return (EINVAL);
2347 	}
2348 	if (error != 0) {
2349 		G_MIRROR_DEBUG(1, "MD5 metadata hash mismatch for provider %s.",
2350 		    cp->provider->name);
2351 		return (error);
2352 	}
2353 
2354 	return (0);
2355 }
2356 
2357 static int
2358 g_mirror_check_metadata(struct g_mirror_softc *sc, struct g_provider *pp,
2359     struct g_mirror_metadata *md)
2360 {
2361 
2362 	if (g_mirror_id2disk(sc, md->md_did) != NULL) {
2363 		G_MIRROR_DEBUG(1, "Disk %s (id=%u) already exists, skipping.",
2364 		    pp->name, md->md_did);
2365 		return (EEXIST);
2366 	}
2367 	if (md->md_all != sc->sc_ndisks) {
2368 		G_MIRROR_DEBUG(1,
2369 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2370 		    "md_all", pp->name, sc->sc_name);
2371 		return (EINVAL);
2372 	}
2373 	if (md->md_slice != sc->sc_slice) {
2374 		G_MIRROR_DEBUG(1,
2375 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2376 		    "md_slice", pp->name, sc->sc_name);
2377 		return (EINVAL);
2378 	}
2379 	if (md->md_balance != sc->sc_balance) {
2380 		G_MIRROR_DEBUG(1,
2381 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2382 		    "md_balance", pp->name, sc->sc_name);
2383 		return (EINVAL);
2384 	}
2385 	if (md->md_mediasize != sc->sc_mediasize) {
2386 		G_MIRROR_DEBUG(1,
2387 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2388 		    "md_mediasize", pp->name, sc->sc_name);
2389 		return (EINVAL);
2390 	}
2391 	if (sc->sc_mediasize > pp->mediasize) {
2392 		G_MIRROR_DEBUG(1,
2393 		    "Invalid size of disk %s (device %s), skipping.", pp->name,
2394 		    sc->sc_name);
2395 		return (EINVAL);
2396 	}
2397 	if (md->md_sectorsize != sc->sc_sectorsize) {
2398 		G_MIRROR_DEBUG(1,
2399 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2400 		    "md_sectorsize", pp->name, sc->sc_name);
2401 		return (EINVAL);
2402 	}
2403 	if ((sc->sc_sectorsize % pp->sectorsize) != 0) {
2404 		G_MIRROR_DEBUG(1,
2405 		    "Invalid sector size of disk %s (device %s), skipping.",
2406 		    pp->name, sc->sc_name);
2407 		return (EINVAL);
2408 	}
2409 	if ((md->md_mflags & ~G_MIRROR_DEVICE_FLAG_MASK) != 0) {
2410 		G_MIRROR_DEBUG(1,
2411 		    "Invalid device flags on disk %s (device %s), skipping.",
2412 		    pp->name, sc->sc_name);
2413 		return (EINVAL);
2414 	}
2415 	if ((md->md_dflags & ~G_MIRROR_DISK_FLAG_MASK) != 0) {
2416 		G_MIRROR_DEBUG(1,
2417 		    "Invalid disk flags on disk %s (device %s), skipping.",
2418 		    pp->name, sc->sc_name);
2419 		return (EINVAL);
2420 	}
2421 	return (0);
2422 }
2423 
2424 int
2425 g_mirror_add_disk(struct g_mirror_softc *sc, struct g_provider *pp,
2426     struct g_mirror_metadata *md)
2427 {
2428 	struct g_mirror_disk *disk;
2429 	int error;
2430 
2431 	g_topology_assert();
2432 	G_MIRROR_DEBUG(2, "Adding disk %s.", pp->name);
2433 
2434 	error = g_mirror_check_metadata(sc, pp, md);
2435 	if (error != 0)
2436 		return (error);
2437 	if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING &&
2438 	    md->md_genid < sc->sc_genid) {
2439 		G_MIRROR_DEBUG(0, "Component %s (device %s) broken, skipping.",
2440 		    pp->name, sc->sc_name);
2441 		return (EINVAL);
2442 	}
2443 	disk = g_mirror_init_disk(sc, pp, md, &error);
2444 	if (disk == NULL)
2445 		return (error);
2446 	error = g_mirror_event_send(disk, G_MIRROR_DISK_STATE_NEW,
2447 	    G_MIRROR_EVENT_WAIT);
2448 	if (error != 0)
2449 		return (error);
2450 	if (md->md_version < G_MIRROR_VERSION) {
2451 		G_MIRROR_DEBUG(0, "Upgrading metadata on %s (v%d->v%d).",
2452 		    pp->name, md->md_version, G_MIRROR_VERSION);
2453 		g_mirror_update_metadata(disk);
2454 	}
2455 	return (0);
2456 }
2457 
2458 static int
2459 g_mirror_access(struct g_provider *pp, int acr, int acw, int ace)
2460 {
2461 	struct g_mirror_softc *sc;
2462 	struct g_mirror_disk *disk;
2463 	int dcr, dcw, dce;
2464 
2465 	g_topology_assert();
2466 	G_MIRROR_DEBUG(2, "Access request for %s: r%dw%de%d.", pp->name, acr,
2467 	    acw, ace);
2468 
2469 	dcr = pp->acr + acr;
2470 	dcw = pp->acw + acw;
2471 	dce = pp->ace + ace;
2472 
2473 	sc = pp->geom->softc;
2474 	if (sc == NULL || LIST_EMPTY(&sc->sc_disks) ||
2475 	    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
2476 		if (acr <= 0 && acw <= 0 && ace <= 0)
2477 			return (0);
2478 		else
2479 			return (ENXIO);
2480 	}
2481 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2482 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
2483 			continue;
2484 		/*
2485 		 * Mark disk as dirty on open and unmark on close.
2486 		 */
2487 		if (pp->acw == 0 && dcw > 0) {
2488 			G_MIRROR_DEBUG(1,
2489 			    "Disk %s (device %s) marked as dirty.",
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 		} else if (pp->acw > 0 && dcw == 0) {
2494 			G_MIRROR_DEBUG(1,
2495 			    "Disk %s (device %s) marked as clean.",
2496 			    g_mirror_get_diskname(disk), sc->sc_name);
2497 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2498 			g_mirror_update_metadata(disk);
2499 		}
2500 	}
2501 	return (0);
2502 }
2503 
2504 static struct g_geom *
2505 g_mirror_create(struct g_class *mp, const struct g_mirror_metadata *md)
2506 {
2507 	struct g_mirror_softc *sc;
2508 	struct g_geom *gp;
2509 	int error, timeout;
2510 
2511 	g_topology_assert();
2512 	G_MIRROR_DEBUG(1, "Creating device %s (id=%u).", md->md_name,
2513 	    md->md_mid);
2514 
2515 	/* One disk is minimum. */
2516 	if (md->md_all < 1)
2517 		return (NULL);
2518 	/*
2519 	 * Action geom.
2520 	 */
2521 	gp = g_new_geomf(mp, "%s", md->md_name);
2522 	sc = malloc(sizeof(*sc), M_MIRROR, M_WAITOK | M_ZERO);
2523 	gp->start = g_mirror_start;
2524 	gp->orphan = g_mirror_orphan;
2525 	gp->access = g_mirror_access;
2526 	gp->dumpconf = g_mirror_dumpconf;
2527 
2528 	sc->sc_id = md->md_mid;
2529 	sc->sc_slice = md->md_slice;
2530 	sc->sc_balance = md->md_balance;
2531 	sc->sc_mediasize = md->md_mediasize;
2532 	sc->sc_sectorsize = md->md_sectorsize;
2533 	sc->sc_ndisks = md->md_all;
2534 	sc->sc_flags = md->md_mflags;
2535 	sc->sc_bump_id = 0;
2536 	sc->sc_idle = 0;
2537 	bioq_init(&sc->sc_queue);
2538 	mtx_init(&sc->sc_queue_mtx, "gmirror:queue", NULL, MTX_DEF);
2539 	LIST_INIT(&sc->sc_disks);
2540 	TAILQ_INIT(&sc->sc_events);
2541 	mtx_init(&sc->sc_events_mtx, "gmirror:events", NULL, MTX_DEF);
2542 	callout_init(&sc->sc_callout, CALLOUT_MPSAFE);
2543 	sc->sc_state = G_MIRROR_DEVICE_STATE_STARTING;
2544 	gp->softc = sc;
2545 	sc->sc_geom = gp;
2546 	sc->sc_provider = NULL;
2547 	/*
2548 	 * Synchronization geom.
2549 	 */
2550 	gp = g_new_geomf(mp, "%s.sync", md->md_name);
2551 	gp->softc = sc;
2552 	gp->orphan = g_mirror_orphan;
2553 	sc->sc_sync.ds_geom = gp;
2554 	sc->sc_sync.ds_ndisks = 0;
2555 	error = kthread_create(g_mirror_worker, sc, &sc->sc_worker, 0, 0,
2556 	    "g_mirror %s", md->md_name);
2557 	if (error != 0) {
2558 		G_MIRROR_DEBUG(1, "Cannot create kernel thread for %s.",
2559 		    sc->sc_name);
2560 		g_destroy_geom(sc->sc_sync.ds_geom);
2561 		mtx_destroy(&sc->sc_events_mtx);
2562 		mtx_destroy(&sc->sc_queue_mtx);
2563 		g_destroy_geom(sc->sc_geom);
2564 		free(sc, M_MIRROR);
2565 		return (NULL);
2566 	}
2567 
2568 	G_MIRROR_DEBUG(0, "Device %s created (id=%u).", sc->sc_name, sc->sc_id);
2569 
2570 	/*
2571 	 * Run timeout.
2572 	 */
2573 	timeout = g_mirror_timeout * hz;
2574 	callout_reset(&sc->sc_callout, timeout, g_mirror_go, sc);
2575 	return (sc->sc_geom);
2576 }
2577 
2578 int
2579 g_mirror_destroy(struct g_mirror_softc *sc, boolean_t force)
2580 {
2581 	struct g_provider *pp;
2582 
2583 	g_topology_assert();
2584 
2585 	if (sc == NULL)
2586 		return (ENXIO);
2587 	pp = sc->sc_provider;
2588 	if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
2589 		if (force) {
2590 			G_MIRROR_DEBUG(1, "Device %s is still open, so it "
2591 			    "can't be definitely removed.", pp->name);
2592 		} else {
2593 			G_MIRROR_DEBUG(1,
2594 			    "Device %s is still open (r%dw%de%d).", pp->name,
2595 			    pp->acr, pp->acw, pp->ace);
2596 			return (EBUSY);
2597 		}
2598 	}
2599 
2600 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2601 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_WAIT;
2602 	g_topology_unlock();
2603 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
2604 	mtx_lock(&sc->sc_queue_mtx);
2605 	wakeup(sc);
2606 	mtx_unlock(&sc->sc_queue_mtx);
2607 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, &sc->sc_worker);
2608 	while (sc->sc_worker != NULL)
2609 		tsleep(&sc->sc_worker, PRIBIO, "m:destroy", hz / 5);
2610 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, &sc->sc_worker);
2611 	g_topology_lock();
2612 	g_mirror_destroy_device(sc);
2613 	free(sc, M_MIRROR);
2614 	return (0);
2615 }
2616 
2617 static void
2618 g_mirror_taste_orphan(struct g_consumer *cp)
2619 {
2620 
2621 	KASSERT(1 == 0, ("%s called while tasting %s.", __func__,
2622 	    cp->provider->name));
2623 }
2624 
2625 static struct g_geom *
2626 g_mirror_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
2627 {
2628 	struct g_mirror_metadata md;
2629 	struct g_mirror_softc *sc;
2630 	struct g_consumer *cp;
2631 	struct g_geom *gp;
2632 	int error;
2633 
2634 	g_topology_assert();
2635 	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
2636 	G_MIRROR_DEBUG(2, "Tasting %s.", pp->name);
2637 
2638 	gp = g_new_geomf(mp, "mirror:taste");
2639 	/*
2640 	 * This orphan function should be never called.
2641 	 */
2642 	gp->orphan = g_mirror_taste_orphan;
2643 	cp = g_new_consumer(gp);
2644 	g_attach(cp, pp);
2645 	error = g_mirror_read_metadata(cp, &md);
2646 	g_detach(cp);
2647 	g_destroy_consumer(cp);
2648 	g_destroy_geom(gp);
2649 	if (error != 0)
2650 		return (NULL);
2651 	gp = NULL;
2652 
2653 	if (md.md_provider[0] != '\0' && strcmp(md.md_provider, pp->name) != 0)
2654 		return (NULL);
2655 	if (md.md_provsize != 0 && md.md_provsize != pp->mediasize)
2656 		return (NULL);
2657 	if ((md.md_dflags & G_MIRROR_DISK_FLAG_INACTIVE) != 0) {
2658 		G_MIRROR_DEBUG(0,
2659 		    "Device %s: provider %s marked as inactive, skipping.",
2660 		    md.md_name, pp->name);
2661 		return (NULL);
2662 	}
2663 	if (g_mirror_debug >= 2)
2664 		mirror_metadata_dump(&md);
2665 
2666 	/*
2667 	 * Let's check if device already exists.
2668 	 */
2669 	sc = NULL;
2670 	LIST_FOREACH(gp, &mp->geom, geom) {
2671 		sc = gp->softc;
2672 		if (sc == NULL)
2673 			continue;
2674 		if (sc->sc_sync.ds_geom == gp)
2675 			continue;
2676 		if (strcmp(md.md_name, sc->sc_name) != 0)
2677 			continue;
2678 		if (md.md_mid != sc->sc_id) {
2679 			G_MIRROR_DEBUG(0, "Device %s already configured.",
2680 			    sc->sc_name);
2681 			return (NULL);
2682 		}
2683 		break;
2684 	}
2685 	if (gp == NULL) {
2686 		gp = g_mirror_create(mp, &md);
2687 		if (gp == NULL) {
2688 			G_MIRROR_DEBUG(0, "Cannot create device %s.",
2689 			    md.md_name);
2690 			return (NULL);
2691 		}
2692 		sc = gp->softc;
2693 	}
2694 	G_MIRROR_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
2695 	error = g_mirror_add_disk(sc, pp, &md);
2696 	if (error != 0) {
2697 		G_MIRROR_DEBUG(0, "Cannot add disk %s to %s (error=%d).",
2698 		    pp->name, gp->name, error);
2699 		if (LIST_EMPTY(&sc->sc_disks))
2700 			g_mirror_destroy(sc, 1);
2701 		return (NULL);
2702 	}
2703 	return (gp);
2704 }
2705 
2706 static int
2707 g_mirror_destroy_geom(struct gctl_req *req __unused,
2708     struct g_class *mp __unused, struct g_geom *gp)
2709 {
2710 
2711 	return (g_mirror_destroy(gp->softc, 0));
2712 }
2713 
2714 static void
2715 g_mirror_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
2716     struct g_consumer *cp, struct g_provider *pp)
2717 {
2718 	struct g_mirror_softc *sc;
2719 
2720 	g_topology_assert();
2721 
2722 	sc = gp->softc;
2723 	if (sc == NULL)
2724 		return;
2725 	/* Skip synchronization geom. */
2726 	if (gp == sc->sc_sync.ds_geom)
2727 		return;
2728 	if (pp != NULL) {
2729 		/* Nothing here. */
2730 	} else if (cp != NULL) {
2731 		struct g_mirror_disk *disk;
2732 
2733 		disk = cp->private;
2734 		if (disk == NULL)
2735 			return;
2736 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)disk->d_id);
2737 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2738 			sbuf_printf(sb, "%s<Synchronized>", indent);
2739 			if (disk->d_sync.ds_offset_done == 0)
2740 				sbuf_printf(sb, "0%%");
2741 			else {
2742 				sbuf_printf(sb, "%u%%",
2743 				    (u_int)((disk->d_sync.ds_offset_done * 100) /
2744 				    sc->sc_provider->mediasize));
2745 			}
2746 			sbuf_printf(sb, "</Synchronized>\n");
2747 		}
2748 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent,
2749 		    disk->d_sync.ds_syncid);
2750 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent,
2751 		    disk->d_genid);
2752 		sbuf_printf(sb, "%s<Flags>", indent);
2753 		if (disk->d_flags == 0)
2754 			sbuf_printf(sb, "NONE");
2755 		else {
2756 			int first = 1;
2757 
2758 #define	ADD_FLAG(flag, name)	do {					\
2759 	if ((disk->d_flags & (flag)) != 0) {				\
2760 		if (!first)						\
2761 			sbuf_printf(sb, ", ");				\
2762 		else							\
2763 			first = 0;					\
2764 		sbuf_printf(sb, name);					\
2765 	}								\
2766 } while (0)
2767 			ADD_FLAG(G_MIRROR_DISK_FLAG_DIRTY, "DIRTY");
2768 			ADD_FLAG(G_MIRROR_DISK_FLAG_HARDCODED, "HARDCODED");
2769 			ADD_FLAG(G_MIRROR_DISK_FLAG_INACTIVE, "INACTIVE");
2770 			ADD_FLAG(G_MIRROR_DISK_FLAG_SYNCHRONIZING,
2771 			    "SYNCHRONIZING");
2772 			ADD_FLAG(G_MIRROR_DISK_FLAG_FORCE_SYNC, "FORCE_SYNC");
2773 #undef	ADD_FLAG
2774 		}
2775 		sbuf_printf(sb, "</Flags>\n");
2776 		sbuf_printf(sb, "%s<Priority>%u</Priority>\n", indent,
2777 		    disk->d_priority);
2778 		sbuf_printf(sb, "%s<State>%s</State>\n", indent,
2779 		    g_mirror_disk_state2str(disk->d_state));
2780 	} else {
2781 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)sc->sc_id);
2782 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent, sc->sc_syncid);
2783 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent, sc->sc_genid);
2784 		sbuf_printf(sb, "%s<Flags>", indent);
2785 		if (sc->sc_flags == 0)
2786 			sbuf_printf(sb, "NONE");
2787 		else {
2788 			int first = 1;
2789 
2790 #define	ADD_FLAG(flag, name)	do {					\
2791 	if ((sc->sc_flags & (flag)) != 0) {				\
2792 		if (!first)						\
2793 			sbuf_printf(sb, ", ");				\
2794 		else							\
2795 			first = 0;					\
2796 		sbuf_printf(sb, name);					\
2797 	}								\
2798 } while (0)
2799 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOAUTOSYNC, "NOAUTOSYNC");
2800 #undef	ADD_FLAG
2801 		}
2802 		sbuf_printf(sb, "</Flags>\n");
2803 		sbuf_printf(sb, "%s<Slice>%u</Slice>\n", indent,
2804 		    (u_int)sc->sc_slice);
2805 		sbuf_printf(sb, "%s<Balance>%s</Balance>\n", indent,
2806 		    balance_name(sc->sc_balance));
2807 		sbuf_printf(sb, "%s<Components>%u</Components>\n", indent,
2808 		    sc->sc_ndisks);
2809 		sbuf_printf(sb, "%s<State>", indent);
2810 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
2811 			sbuf_printf(sb, "%s", "STARTING");
2812 		else if (sc->sc_ndisks ==
2813 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE))
2814 			sbuf_printf(sb, "%s", "COMPLETE");
2815 		else
2816 			sbuf_printf(sb, "%s", "DEGRADED");
2817 		sbuf_printf(sb, "</State>\n");
2818 	}
2819 }
2820 
2821 static void
2822 g_mirror_shutdown(void *arg, int howto)
2823 {
2824 	struct g_class *mp;
2825 	struct g_geom *gp, *gp2;
2826 
2827 	mp = arg;
2828 	DROP_GIANT();
2829 	g_topology_lock();
2830 	LIST_FOREACH_SAFE(gp, &mp->geom, geom, gp2) {
2831 		if (gp->softc == NULL)
2832 			continue;
2833 		g_mirror_destroy(gp->softc, 1);
2834 	}
2835 	g_topology_unlock();
2836 	PICKUP_GIANT();
2837 #if 0
2838 	tsleep(&gp, PRIBIO, "m:shutdown", hz * 20);
2839 #endif
2840 }
2841 
2842 static void
2843 g_mirror_init(struct g_class *mp)
2844 {
2845 
2846 	g_mirror_ehtag = EVENTHANDLER_REGISTER(shutdown_post_sync,
2847 	    g_mirror_shutdown, mp, SHUTDOWN_PRI_FIRST);
2848 	if (g_mirror_ehtag == NULL)
2849 		G_MIRROR_DEBUG(0, "Warning! Cannot register shutdown event.");
2850 }
2851 
2852 static void
2853 g_mirror_fini(struct g_class *mp)
2854 {
2855 
2856 	if (g_mirror_ehtag == NULL)
2857 		return;
2858 	EVENTHANDLER_DEREGISTER(shutdown_post_sync, g_mirror_ehtag);
2859 }
2860 
2861 static int
2862 g_mirror_can_go(void)
2863 {
2864 	struct g_mirror_softc *sc;
2865 	struct g_geom *gp;
2866 	struct g_provider *pp;
2867 	int can_go;
2868 
2869 	DROP_GIANT();
2870 	can_go = 1;
2871 	g_topology_lock();
2872 	LIST_FOREACH(gp, &g_mirror_class.geom, geom) {
2873 		sc = gp->softc;
2874 		if (sc == NULL) {
2875 			can_go = 0;
2876 			break;
2877 		}
2878 		pp = sc->sc_provider;
2879 		if (pp == NULL || pp->error != 0) {
2880 			can_go = 0;
2881 			break;
2882 		}
2883 	}
2884 	g_topology_unlock();
2885 	PICKUP_GIANT();
2886 	return (can_go);
2887 }
2888 
2889 static void
2890 g_mirror_rootwait(void)
2891 {
2892 
2893 	/*
2894 	 * HACK: Wait for GEOM, because g_mirror_rootwait() can be called,
2895 	 * HACK: before we get providers for tasting.
2896 	 */
2897 	tsleep(&g_mirror_class, PRIBIO, "mroot", hz * 3);
2898 	/*
2899 	 * Wait for mirrors in degraded state.
2900 	 */
2901 	for (;;) {
2902 		if (g_mirror_can_go())
2903 			break;
2904 		tsleep(&g_mirror_class, PRIBIO, "mroot", hz);
2905 	}
2906 }
2907 
2908 SYSINIT(g_mirror_root, SI_SUB_RAID, SI_ORDER_FIRST, g_mirror_rootwait, NULL)
2909 
2910 DECLARE_GEOM_CLASS(g_mirror_class, g_mirror);
2911