xref: /freebsd/sys/geom/mirror/g_mirror.c (revision 0f2bd1e89db1a2f09268edea21e0ead329e092df)
1 /*-
2  * Copyright (c) 2004-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/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_disconnect_on_failure = 1;
66 TUNABLE_INT("kern.geom.mirror.disconnect_on_failure",
67     &g_mirror_disconnect_on_failure);
68 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, disconnect_on_failure, CTLFLAG_RW,
69     &g_mirror_disconnect_on_failure, 0, "Disconnect component on I/O failure.");
70 static u_int g_mirror_syncreqs = 2;
71 TUNABLE_INT("kern.geom.mirror.sync_requests", &g_mirror_syncreqs);
72 SYSCTL_UINT(_kern_geom_mirror, OID_AUTO, sync_requests, CTLFLAG_RDTUN,
73     &g_mirror_syncreqs, 0, "Parallel synchronization I/O requests.");
74 
75 #define	MSLEEP(ident, mtx, priority, wmesg, timeout)	do {		\
76 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, (ident));	\
77 	msleep((ident), (mtx), (priority), (wmesg), (timeout));		\
78 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, (ident));	\
79 } while (0)
80 
81 static eventhandler_tag g_mirror_pre_sync = NULL;
82 
83 static int g_mirror_destroy_geom(struct gctl_req *req, struct g_class *mp,
84     struct g_geom *gp);
85 static g_taste_t g_mirror_taste;
86 static void g_mirror_init(struct g_class *mp);
87 static void g_mirror_fini(struct g_class *mp);
88 
89 struct g_class g_mirror_class = {
90 	.name = G_MIRROR_CLASS_NAME,
91 	.version = G_VERSION,
92 	.ctlreq = g_mirror_config,
93 	.taste = g_mirror_taste,
94 	.destroy_geom = g_mirror_destroy_geom,
95 	.init = g_mirror_init,
96 	.fini = g_mirror_fini
97 };
98 
99 
100 static void g_mirror_destroy_provider(struct g_mirror_softc *sc);
101 static int g_mirror_update_disk(struct g_mirror_disk *disk, u_int state);
102 static void g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force);
103 static void g_mirror_dumpconf(struct sbuf *sb, const char *indent,
104     struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp);
105 static void g_mirror_sync_stop(struct g_mirror_disk *disk, int type);
106 static void g_mirror_register_request(struct bio *bp);
107 static void g_mirror_sync_release(struct g_mirror_softc *sc);
108 
109 
110 static const char *
111 g_mirror_disk_state2str(int state)
112 {
113 
114 	switch (state) {
115 	case G_MIRROR_DISK_STATE_NONE:
116 		return ("NONE");
117 	case G_MIRROR_DISK_STATE_NEW:
118 		return ("NEW");
119 	case G_MIRROR_DISK_STATE_ACTIVE:
120 		return ("ACTIVE");
121 	case G_MIRROR_DISK_STATE_STALE:
122 		return ("STALE");
123 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
124 		return ("SYNCHRONIZING");
125 	case G_MIRROR_DISK_STATE_DISCONNECTED:
126 		return ("DISCONNECTED");
127 	case G_MIRROR_DISK_STATE_DESTROY:
128 		return ("DESTROY");
129 	default:
130 		return ("INVALID");
131 	}
132 }
133 
134 static const char *
135 g_mirror_device_state2str(int state)
136 {
137 
138 	switch (state) {
139 	case G_MIRROR_DEVICE_STATE_STARTING:
140 		return ("STARTING");
141 	case G_MIRROR_DEVICE_STATE_RUNNING:
142 		return ("RUNNING");
143 	default:
144 		return ("INVALID");
145 	}
146 }
147 
148 static const char *
149 g_mirror_get_diskname(struct g_mirror_disk *disk)
150 {
151 
152 	if (disk->d_consumer == NULL || disk->d_consumer->provider == NULL)
153 		return ("[unknown]");
154 	return (disk->d_name);
155 }
156 
157 /*
158  * --- Events handling functions ---
159  * Events in geom_mirror are used to maintain disks and device status
160  * from one thread to simplify locking.
161  */
162 static void
163 g_mirror_event_free(struct g_mirror_event *ep)
164 {
165 
166 	free(ep, M_MIRROR);
167 }
168 
169 int
170 g_mirror_event_send(void *arg, int state, int flags)
171 {
172 	struct g_mirror_softc *sc;
173 	struct g_mirror_disk *disk;
174 	struct g_mirror_event *ep;
175 	int error;
176 
177 	ep = malloc(sizeof(*ep), M_MIRROR, M_WAITOK);
178 	G_MIRROR_DEBUG(4, "%s: Sending event %p.", __func__, ep);
179 	if ((flags & G_MIRROR_EVENT_DEVICE) != 0) {
180 		disk = NULL;
181 		sc = arg;
182 	} else {
183 		disk = arg;
184 		sc = disk->d_softc;
185 	}
186 	ep->e_disk = disk;
187 	ep->e_state = state;
188 	ep->e_flags = flags;
189 	ep->e_error = 0;
190 	mtx_lock(&sc->sc_events_mtx);
191 	TAILQ_INSERT_TAIL(&sc->sc_events, ep, e_next);
192 	mtx_unlock(&sc->sc_events_mtx);
193 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
194 	mtx_lock(&sc->sc_queue_mtx);
195 	wakeup(sc);
196 	mtx_unlock(&sc->sc_queue_mtx);
197 	if ((flags & G_MIRROR_EVENT_DONTWAIT) != 0)
198 		return (0);
199 	sx_assert(&sc->sc_lock, SX_XLOCKED);
200 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, ep);
201 	sx_xunlock(&sc->sc_lock);
202 	while ((ep->e_flags & G_MIRROR_EVENT_DONE) == 0) {
203 		mtx_lock(&sc->sc_events_mtx);
204 		MSLEEP(ep, &sc->sc_events_mtx, PRIBIO | PDROP, "m:event",
205 		    hz * 5);
206 	}
207 	error = ep->e_error;
208 	g_mirror_event_free(ep);
209 	sx_xlock(&sc->sc_lock);
210 	return (error);
211 }
212 
213 static struct g_mirror_event *
214 g_mirror_event_get(struct g_mirror_softc *sc)
215 {
216 	struct g_mirror_event *ep;
217 
218 	mtx_lock(&sc->sc_events_mtx);
219 	ep = TAILQ_FIRST(&sc->sc_events);
220 	mtx_unlock(&sc->sc_events_mtx);
221 	return (ep);
222 }
223 
224 static void
225 g_mirror_event_remove(struct g_mirror_softc *sc, struct g_mirror_event *ep)
226 {
227 
228 	mtx_lock(&sc->sc_events_mtx);
229 	TAILQ_REMOVE(&sc->sc_events, ep, e_next);
230 	mtx_unlock(&sc->sc_events_mtx);
231 }
232 
233 static void
234 g_mirror_event_cancel(struct g_mirror_disk *disk)
235 {
236 	struct g_mirror_softc *sc;
237 	struct g_mirror_event *ep, *tmpep;
238 
239 	sc = disk->d_softc;
240 	sx_assert(&sc->sc_lock, SX_XLOCKED);
241 
242 	mtx_lock(&sc->sc_events_mtx);
243 	TAILQ_FOREACH_SAFE(ep, &sc->sc_events, e_next, tmpep) {
244 		if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0)
245 			continue;
246 		if (ep->e_disk != disk)
247 			continue;
248 		TAILQ_REMOVE(&sc->sc_events, ep, e_next);
249 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
250 			g_mirror_event_free(ep);
251 		else {
252 			ep->e_error = ECANCELED;
253 			wakeup(ep);
254 		}
255 	}
256 	mtx_unlock(&sc->sc_events_mtx);
257 }
258 
259 /*
260  * Return the number of disks in given state.
261  * If state is equal to -1, count all connected disks.
262  */
263 u_int
264 g_mirror_ndisks(struct g_mirror_softc *sc, int state)
265 {
266 	struct g_mirror_disk *disk;
267 	u_int n = 0;
268 
269 	sx_assert(&sc->sc_lock, SX_LOCKED);
270 
271 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
272 		if (state == -1 || disk->d_state == state)
273 			n++;
274 	}
275 	return (n);
276 }
277 
278 /*
279  * Find a disk in mirror by its disk ID.
280  */
281 static struct g_mirror_disk *
282 g_mirror_id2disk(struct g_mirror_softc *sc, uint32_t id)
283 {
284 	struct g_mirror_disk *disk;
285 
286 	sx_assert(&sc->sc_lock, SX_XLOCKED);
287 
288 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
289 		if (disk->d_id == id)
290 			return (disk);
291 	}
292 	return (NULL);
293 }
294 
295 static u_int
296 g_mirror_nrequests(struct g_mirror_softc *sc, struct g_consumer *cp)
297 {
298 	struct bio *bp;
299 	u_int nreqs = 0;
300 
301 	mtx_lock(&sc->sc_queue_mtx);
302 	TAILQ_FOREACH(bp, &sc->sc_queue.queue, bio_queue) {
303 		if (bp->bio_from == cp)
304 			nreqs++;
305 	}
306 	mtx_unlock(&sc->sc_queue_mtx);
307 	return (nreqs);
308 }
309 
310 static int
311 g_mirror_is_busy(struct g_mirror_softc *sc, struct g_consumer *cp)
312 {
313 
314 	if (cp->index > 0) {
315 		G_MIRROR_DEBUG(2,
316 		    "I/O requests for %s exist, can't destroy it now.",
317 		    cp->provider->name);
318 		return (1);
319 	}
320 	if (g_mirror_nrequests(sc, cp) > 0) {
321 		G_MIRROR_DEBUG(2,
322 		    "I/O requests for %s in queue, can't destroy it now.",
323 		    cp->provider->name);
324 		return (1);
325 	}
326 	return (0);
327 }
328 
329 static void
330 g_mirror_destroy_consumer(void *arg, int flags __unused)
331 {
332 	struct g_consumer *cp;
333 
334 	g_topology_assert();
335 
336 	cp = arg;
337 	G_MIRROR_DEBUG(1, "Consumer %s destroyed.", cp->provider->name);
338 	g_detach(cp);
339 	g_destroy_consumer(cp);
340 }
341 
342 static void
343 g_mirror_kill_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
344 {
345 	struct g_provider *pp;
346 	int retaste_wait;
347 
348 	g_topology_assert();
349 
350 	cp->private = NULL;
351 	if (g_mirror_is_busy(sc, cp))
352 		return;
353 	pp = cp->provider;
354 	retaste_wait = 0;
355 	if (cp->acw == 1) {
356 		if ((pp->geom->flags & G_GEOM_WITHER) == 0)
357 			retaste_wait = 1;
358 	}
359 	G_MIRROR_DEBUG(2, "Access %s r%dw%de%d = %d", pp->name, -cp->acr,
360 	    -cp->acw, -cp->ace, 0);
361 	if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
362 		g_access(cp, -cp->acr, -cp->acw, -cp->ace);
363 	if (retaste_wait) {
364 		/*
365 		 * After retaste event was send (inside g_access()), we can send
366 		 * event to detach and destroy consumer.
367 		 * A class, which has consumer to the given provider connected
368 		 * will not receive retaste event for the provider.
369 		 * This is the way how I ignore retaste events when I close
370 		 * consumers opened for write: I detach and destroy consumer
371 		 * after retaste event is sent.
372 		 */
373 		g_post_event(g_mirror_destroy_consumer, cp, M_WAITOK, NULL);
374 		return;
375 	}
376 	G_MIRROR_DEBUG(1, "Consumer %s destroyed.", pp->name);
377 	g_detach(cp);
378 	g_destroy_consumer(cp);
379 }
380 
381 static int
382 g_mirror_connect_disk(struct g_mirror_disk *disk, struct g_provider *pp)
383 {
384 	struct g_consumer *cp;
385 	int error;
386 
387 	g_topology_assert_not();
388 	KASSERT(disk->d_consumer == NULL,
389 	    ("Disk already connected (device %s).", disk->d_softc->sc_name));
390 
391 	g_topology_lock();
392 	cp = g_new_consumer(disk->d_softc->sc_geom);
393 	error = g_attach(cp, pp);
394 	if (error != 0) {
395 		g_destroy_consumer(cp);
396 		g_topology_unlock();
397 		return (error);
398 	}
399 	error = g_access(cp, 1, 1, 1);
400 	if (error != 0) {
401 		g_detach(cp);
402 		g_destroy_consumer(cp);
403 		g_topology_unlock();
404 		G_MIRROR_DEBUG(0, "Cannot open consumer %s (error=%d).",
405 		    pp->name, error);
406 		return (error);
407 	}
408 	g_topology_unlock();
409 	disk->d_consumer = cp;
410 	disk->d_consumer->private = disk;
411 	disk->d_consumer->index = 0;
412 
413 	G_MIRROR_DEBUG(2, "Disk %s connected.", g_mirror_get_diskname(disk));
414 	return (0);
415 }
416 
417 static void
418 g_mirror_disconnect_consumer(struct g_mirror_softc *sc, struct g_consumer *cp)
419 {
420 
421 	g_topology_assert();
422 
423 	if (cp == NULL)
424 		return;
425 	if (cp->provider != NULL)
426 		g_mirror_kill_consumer(sc, cp);
427 	else
428 		g_destroy_consumer(cp);
429 }
430 
431 /*
432  * Initialize disk. This means allocate memory, create consumer, attach it
433  * to the provider and open access (r1w1e1) to it.
434  */
435 static struct g_mirror_disk *
436 g_mirror_init_disk(struct g_mirror_softc *sc, struct g_provider *pp,
437     struct g_mirror_metadata *md, int *errorp)
438 {
439 	struct g_mirror_disk *disk;
440 	int error;
441 
442 	disk = malloc(sizeof(*disk), M_MIRROR, M_NOWAIT | M_ZERO);
443 	if (disk == NULL) {
444 		error = ENOMEM;
445 		goto fail;
446 	}
447 	disk->d_softc = sc;
448 	error = g_mirror_connect_disk(disk, pp);
449 	if (error != 0)
450 		goto fail;
451 	disk->d_id = md->md_did;
452 	disk->d_state = G_MIRROR_DISK_STATE_NONE;
453 	disk->d_priority = md->md_priority;
454 	disk->d_flags = md->md_dflags;
455 	if (md->md_provider[0] != '\0')
456 		disk->d_flags |= G_MIRROR_DISK_FLAG_HARDCODED;
457 	disk->d_sync.ds_consumer = NULL;
458 	disk->d_sync.ds_offset = md->md_sync_offset;
459 	disk->d_sync.ds_offset_done = md->md_sync_offset;
460 	disk->d_genid = md->md_genid;
461 	disk->d_sync.ds_syncid = md->md_syncid;
462 	if (errorp != NULL)
463 		*errorp = 0;
464 	return (disk);
465 fail:
466 	if (errorp != NULL)
467 		*errorp = error;
468 	if (disk != NULL)
469 		free(disk, M_MIRROR);
470 	return (NULL);
471 }
472 
473 static void
474 g_mirror_destroy_disk(struct g_mirror_disk *disk)
475 {
476 	struct g_mirror_softc *sc;
477 
478 	g_topology_assert_not();
479 	sc = disk->d_softc;
480 	sx_assert(&sc->sc_lock, SX_XLOCKED);
481 
482 	LIST_REMOVE(disk, d_next);
483 	g_mirror_event_cancel(disk);
484 	if (sc->sc_hint == disk)
485 		sc->sc_hint = NULL;
486 	switch (disk->d_state) {
487 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
488 		g_mirror_sync_stop(disk, 1);
489 		/* FALLTHROUGH */
490 	case G_MIRROR_DISK_STATE_NEW:
491 	case G_MIRROR_DISK_STATE_STALE:
492 	case G_MIRROR_DISK_STATE_ACTIVE:
493 		g_topology_lock();
494 		g_mirror_disconnect_consumer(sc, disk->d_consumer);
495 		g_topology_unlock();
496 		free(disk, M_MIRROR);
497 		break;
498 	default:
499 		KASSERT(0 == 1, ("Wrong disk state (%s, %s).",
500 		    g_mirror_get_diskname(disk),
501 		    g_mirror_disk_state2str(disk->d_state)));
502 	}
503 }
504 
505 static void
506 g_mirror_destroy_device(struct g_mirror_softc *sc)
507 {
508 	struct g_mirror_disk *disk;
509 	struct g_mirror_event *ep;
510 	struct g_geom *gp;
511 	struct g_consumer *cp, *tmpcp;
512 
513 	g_topology_assert_not();
514 	sx_assert(&sc->sc_lock, SX_XLOCKED);
515 
516 	gp = sc->sc_geom;
517 	if (sc->sc_provider != NULL)
518 		g_mirror_destroy_provider(sc);
519 	for (disk = LIST_FIRST(&sc->sc_disks); disk != NULL;
520 	    disk = LIST_FIRST(&sc->sc_disks)) {
521 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
522 		g_mirror_update_metadata(disk);
523 		g_mirror_destroy_disk(disk);
524 	}
525 	while ((ep = g_mirror_event_get(sc)) != NULL) {
526 		g_mirror_event_remove(sc, ep);
527 		if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0)
528 			g_mirror_event_free(ep);
529 		else {
530 			ep->e_error = ECANCELED;
531 			ep->e_flags |= G_MIRROR_EVENT_DONE;
532 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, ep);
533 			mtx_lock(&sc->sc_events_mtx);
534 			wakeup(ep);
535 			mtx_unlock(&sc->sc_events_mtx);
536 		}
537 	}
538 	callout_drain(&sc->sc_callout);
539 
540 	g_topology_lock();
541 	LIST_FOREACH_SAFE(cp, &sc->sc_sync.ds_geom->consumer, consumer, tmpcp) {
542 		g_mirror_disconnect_consumer(sc, cp);
543 	}
544 	g_wither_geom(sc->sc_sync.ds_geom, ENXIO);
545 	G_MIRROR_DEBUG(0, "Device %s destroyed.", gp->name);
546 	g_wither_geom(gp, ENXIO);
547 	g_topology_unlock();
548 	mtx_destroy(&sc->sc_queue_mtx);
549 	mtx_destroy(&sc->sc_events_mtx);
550 	sx_xunlock(&sc->sc_lock);
551 	sx_destroy(&sc->sc_lock);
552 }
553 
554 static void
555 g_mirror_orphan(struct g_consumer *cp)
556 {
557 	struct g_mirror_disk *disk;
558 
559 	g_topology_assert();
560 
561 	disk = cp->private;
562 	if (disk == NULL)
563 		return;
564 	disk->d_softc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
565 	g_mirror_event_send(disk, G_MIRROR_DISK_STATE_DISCONNECTED,
566 	    G_MIRROR_EVENT_DONTWAIT);
567 }
568 
569 /*
570  * Function should return the next active disk on the list.
571  * It is possible that it will be the same disk as given.
572  * If there are no active disks on list, NULL is returned.
573  */
574 static __inline struct g_mirror_disk *
575 g_mirror_find_next(struct g_mirror_softc *sc, struct g_mirror_disk *disk)
576 {
577 	struct g_mirror_disk *dp;
578 
579 	for (dp = LIST_NEXT(disk, d_next); dp != disk;
580 	    dp = LIST_NEXT(dp, d_next)) {
581 		if (dp == NULL)
582 			dp = LIST_FIRST(&sc->sc_disks);
583 		if (dp->d_state == G_MIRROR_DISK_STATE_ACTIVE)
584 			break;
585 	}
586 	if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
587 		return (NULL);
588 	return (dp);
589 }
590 
591 static struct g_mirror_disk *
592 g_mirror_get_disk(struct g_mirror_softc *sc)
593 {
594 	struct g_mirror_disk *disk;
595 
596 	if (sc->sc_hint == NULL) {
597 		sc->sc_hint = LIST_FIRST(&sc->sc_disks);
598 		if (sc->sc_hint == NULL)
599 			return (NULL);
600 	}
601 	disk = sc->sc_hint;
602 	if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE) {
603 		disk = g_mirror_find_next(sc, disk);
604 		if (disk == NULL)
605 			return (NULL);
606 	}
607 	sc->sc_hint = g_mirror_find_next(sc, disk);
608 	return (disk);
609 }
610 
611 static int
612 g_mirror_write_metadata(struct g_mirror_disk *disk,
613     struct g_mirror_metadata *md)
614 {
615 	struct g_mirror_softc *sc;
616 	struct g_consumer *cp;
617 	off_t offset, length;
618 	u_char *sector;
619 	int error = 0;
620 
621 	g_topology_assert_not();
622 	sc = disk->d_softc;
623 	sx_assert(&sc->sc_lock, SX_LOCKED);
624 
625 	cp = disk->d_consumer;
626 	KASSERT(cp != NULL, ("NULL consumer (%s).", sc->sc_name));
627 	KASSERT(cp->provider != NULL, ("NULL provider (%s).", sc->sc_name));
628 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
629 	    ("Consumer %s closed? (r%dw%de%d).", cp->provider->name, cp->acr,
630 	    cp->acw, cp->ace));
631 	length = cp->provider->sectorsize;
632 	offset = cp->provider->mediasize - length;
633 	sector = malloc((size_t)length, M_MIRROR, M_WAITOK | M_ZERO);
634 	if (md != NULL)
635 		mirror_metadata_encode(md, sector);
636 	error = g_write_data(cp, offset, sector, length);
637 	free(sector, M_MIRROR);
638 	if (error != 0) {
639 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_BROKEN) == 0) {
640 			disk->d_flags |= G_MIRROR_DISK_FLAG_BROKEN;
641 			G_MIRROR_DEBUG(0, "Cannot write metadata on %s "
642 			    "(device=%s, error=%d).",
643 			    g_mirror_get_diskname(disk), sc->sc_name, error);
644 		} else {
645 			G_MIRROR_DEBUG(1, "Cannot write metadata on %s "
646 			    "(device=%s, error=%d).",
647 			    g_mirror_get_diskname(disk), sc->sc_name, error);
648 		}
649 		if (g_mirror_disconnect_on_failure &&
650 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 1) {
651 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
652 			g_mirror_event_send(disk,
653 			    G_MIRROR_DISK_STATE_DISCONNECTED,
654 			    G_MIRROR_EVENT_DONTWAIT);
655 		}
656 	}
657 	return (error);
658 }
659 
660 static int
661 g_mirror_clear_metadata(struct g_mirror_disk *disk)
662 {
663 	int error;
664 
665 	g_topology_assert_not();
666 	sx_assert(&disk->d_softc->sc_lock, SX_LOCKED);
667 
668 	error = g_mirror_write_metadata(disk, NULL);
669 	if (error == 0) {
670 		G_MIRROR_DEBUG(2, "Metadata on %s cleared.",
671 		    g_mirror_get_diskname(disk));
672 	} else {
673 		G_MIRROR_DEBUG(0,
674 		    "Cannot clear metadata on disk %s (error=%d).",
675 		    g_mirror_get_diskname(disk), error);
676 	}
677 	return (error);
678 }
679 
680 void
681 g_mirror_fill_metadata(struct g_mirror_softc *sc, struct g_mirror_disk *disk,
682     struct g_mirror_metadata *md)
683 {
684 
685 	strlcpy(md->md_magic, G_MIRROR_MAGIC, sizeof(md->md_magic));
686 	md->md_version = G_MIRROR_VERSION;
687 	strlcpy(md->md_name, sc->sc_name, sizeof(md->md_name));
688 	md->md_mid = sc->sc_id;
689 	md->md_all = sc->sc_ndisks;
690 	md->md_slice = sc->sc_slice;
691 	md->md_balance = sc->sc_balance;
692 	md->md_genid = sc->sc_genid;
693 	md->md_mediasize = sc->sc_mediasize;
694 	md->md_sectorsize = sc->sc_sectorsize;
695 	md->md_mflags = (sc->sc_flags & G_MIRROR_DEVICE_FLAG_MASK);
696 	bzero(md->md_provider, sizeof(md->md_provider));
697 	if (disk == NULL) {
698 		md->md_did = arc4random();
699 		md->md_priority = 0;
700 		md->md_syncid = 0;
701 		md->md_dflags = 0;
702 		md->md_sync_offset = 0;
703 		md->md_provsize = 0;
704 	} else {
705 		md->md_did = disk->d_id;
706 		md->md_priority = disk->d_priority;
707 		md->md_syncid = disk->d_sync.ds_syncid;
708 		md->md_dflags = (disk->d_flags & G_MIRROR_DISK_FLAG_MASK);
709 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
710 			md->md_sync_offset = disk->d_sync.ds_offset_done;
711 		else
712 			md->md_sync_offset = 0;
713 		if ((disk->d_flags & G_MIRROR_DISK_FLAG_HARDCODED) != 0) {
714 			strlcpy(md->md_provider,
715 			    disk->d_consumer->provider->name,
716 			    sizeof(md->md_provider));
717 		}
718 		md->md_provsize = disk->d_consumer->provider->mediasize;
719 	}
720 }
721 
722 void
723 g_mirror_update_metadata(struct g_mirror_disk *disk)
724 {
725 	struct g_mirror_softc *sc;
726 	struct g_mirror_metadata md;
727 	int error;
728 
729 	g_topology_assert_not();
730 	sc = disk->d_softc;
731 	sx_assert(&sc->sc_lock, SX_LOCKED);
732 
733 	g_mirror_fill_metadata(sc, disk, &md);
734 	error = g_mirror_write_metadata(disk, &md);
735 	if (error == 0) {
736 		G_MIRROR_DEBUG(2, "Metadata on %s updated.",
737 		    g_mirror_get_diskname(disk));
738 	} else {
739 		G_MIRROR_DEBUG(0,
740 		    "Cannot update metadata on disk %s (error=%d).",
741 		    g_mirror_get_diskname(disk), error);
742 	}
743 }
744 
745 static void
746 g_mirror_bump_syncid(struct g_mirror_softc *sc)
747 {
748 	struct g_mirror_disk *disk;
749 
750 	g_topology_assert_not();
751 	sx_assert(&sc->sc_lock, SX_XLOCKED);
752 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
753 	    ("%s called with no active disks (device=%s).", __func__,
754 	    sc->sc_name));
755 
756 	sc->sc_syncid++;
757 	G_MIRROR_DEBUG(1, "Device %s: syncid bumped to %u.", sc->sc_name,
758 	    sc->sc_syncid);
759 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
760 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
761 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
762 			disk->d_sync.ds_syncid = sc->sc_syncid;
763 			g_mirror_update_metadata(disk);
764 		}
765 	}
766 }
767 
768 static void
769 g_mirror_bump_genid(struct g_mirror_softc *sc)
770 {
771 	struct g_mirror_disk *disk;
772 
773 	g_topology_assert_not();
774 	sx_assert(&sc->sc_lock, SX_XLOCKED);
775 	KASSERT(g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 0,
776 	    ("%s called with no active disks (device=%s).", __func__,
777 	    sc->sc_name));
778 
779 	sc->sc_genid++;
780 	G_MIRROR_DEBUG(1, "Device %s: genid bumped to %u.", sc->sc_name,
781 	    sc->sc_genid);
782 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
783 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
784 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
785 			disk->d_genid = sc->sc_genid;
786 			g_mirror_update_metadata(disk);
787 		}
788 	}
789 }
790 
791 static int
792 g_mirror_idle(struct g_mirror_softc *sc, int acw)
793 {
794 	struct g_mirror_disk *disk;
795 	int timeout;
796 
797 	g_topology_assert_not();
798 	sx_assert(&sc->sc_lock, SX_XLOCKED);
799 
800 	if (sc->sc_provider == NULL)
801 		return (0);
802 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
803 		return (0);
804 	if (sc->sc_idle)
805 		return (0);
806 	if (sc->sc_writes > 0)
807 		return (0);
808 	if (acw > 0 || (acw == -1 && sc->sc_provider->acw > 0)) {
809 		timeout = g_mirror_idletime - (time_uptime - sc->sc_last_write);
810 		if (timeout > 0)
811 			return (timeout);
812 	}
813 	sc->sc_idle = 1;
814 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
815 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
816 			continue;
817 		G_MIRROR_DEBUG(1, "Disk %s (device %s) marked as clean.",
818 		    g_mirror_get_diskname(disk), sc->sc_name);
819 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
820 		g_mirror_update_metadata(disk);
821 	}
822 	return (0);
823 }
824 
825 static void
826 g_mirror_unidle(struct g_mirror_softc *sc)
827 {
828 	struct g_mirror_disk *disk;
829 
830 	g_topology_assert_not();
831 	sx_assert(&sc->sc_lock, SX_XLOCKED);
832 
833 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
834 		return;
835 	sc->sc_idle = 0;
836 	sc->sc_last_write = time_uptime;
837 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
838 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
839 			continue;
840 		G_MIRROR_DEBUG(1, "Disk %s (device %s) marked as dirty.",
841 		    g_mirror_get_diskname(disk), sc->sc_name);
842 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
843 		g_mirror_update_metadata(disk);
844 	}
845 }
846 
847 static void
848 g_mirror_done(struct bio *bp)
849 {
850 	struct g_mirror_softc *sc;
851 
852 	sc = bp->bio_from->geom->softc;
853 	bp->bio_cflags = G_MIRROR_BIO_FLAG_REGULAR;
854 	mtx_lock(&sc->sc_queue_mtx);
855 	bioq_disksort(&sc->sc_queue, bp);
856 	mtx_unlock(&sc->sc_queue_mtx);
857 	wakeup(sc);
858 }
859 
860 static void
861 g_mirror_regular_request(struct bio *bp)
862 {
863 	struct g_mirror_softc *sc;
864 	struct g_mirror_disk *disk;
865 	struct bio *pbp;
866 
867 	g_topology_assert_not();
868 
869 	pbp = bp->bio_parent;
870 	sc = pbp->bio_to->geom->softc;
871 	bp->bio_from->index--;
872 	if (bp->bio_cmd == BIO_WRITE)
873 		sc->sc_writes--;
874 	disk = bp->bio_from->private;
875 	if (disk == NULL) {
876 		g_topology_lock();
877 		g_mirror_kill_consumer(sc, bp->bio_from);
878 		g_topology_unlock();
879 	}
880 
881 	pbp->bio_inbed++;
882 	KASSERT(pbp->bio_inbed <= pbp->bio_children,
883 	    ("bio_inbed (%u) is bigger than bio_children (%u).", pbp->bio_inbed,
884 	    pbp->bio_children));
885 	if (bp->bio_error == 0 && pbp->bio_error == 0) {
886 		G_MIRROR_LOGREQ(3, bp, "Request delivered.");
887 		g_destroy_bio(bp);
888 		if (pbp->bio_children == pbp->bio_inbed) {
889 			G_MIRROR_LOGREQ(3, pbp, "Request delivered.");
890 			pbp->bio_completed = pbp->bio_length;
891 			if (pbp->bio_cmd == BIO_WRITE) {
892 				bioq_remove(&sc->sc_inflight, pbp);
893 				/* Release delayed sync requests if possible. */
894 				g_mirror_sync_release(sc);
895 			}
896 			g_io_deliver(pbp, pbp->bio_error);
897 		}
898 		return;
899 	} else if (bp->bio_error != 0) {
900 		if (pbp->bio_error == 0)
901 			pbp->bio_error = bp->bio_error;
902 		if (disk != NULL) {
903 			if ((disk->d_flags & G_MIRROR_DISK_FLAG_BROKEN) == 0) {
904 				disk->d_flags |= G_MIRROR_DISK_FLAG_BROKEN;
905 				G_MIRROR_LOGREQ(0, bp,
906 				    "Request failed (error=%d).",
907 				    bp->bio_error);
908 			} else {
909 				G_MIRROR_LOGREQ(1, bp,
910 				    "Request failed (error=%d).",
911 				    bp->bio_error);
912 			}
913 			if (g_mirror_disconnect_on_failure &&
914 			    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) > 1)
915 			{
916 				sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
917 				g_mirror_event_send(disk,
918 				    G_MIRROR_DISK_STATE_DISCONNECTED,
919 				    G_MIRROR_EVENT_DONTWAIT);
920 			}
921 		}
922 		switch (pbp->bio_cmd) {
923 		case BIO_DELETE:
924 		case BIO_WRITE:
925 			pbp->bio_inbed--;
926 			pbp->bio_children--;
927 			break;
928 		}
929 	}
930 	g_destroy_bio(bp);
931 
932 	switch (pbp->bio_cmd) {
933 	case BIO_READ:
934 		if (pbp->bio_inbed < pbp->bio_children)
935 			break;
936 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 1)
937 			g_io_deliver(pbp, pbp->bio_error);
938 		else {
939 			pbp->bio_error = 0;
940 			mtx_lock(&sc->sc_queue_mtx);
941 			bioq_disksort(&sc->sc_queue, pbp);
942 			mtx_unlock(&sc->sc_queue_mtx);
943 			G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
944 			wakeup(sc);
945 		}
946 		break;
947 	case BIO_DELETE:
948 	case BIO_WRITE:
949 		if (pbp->bio_children == 0) {
950 			/*
951 			 * All requests failed.
952 			 */
953 		} else if (pbp->bio_inbed < pbp->bio_children) {
954 			/* Do nothing. */
955 			break;
956 		} else if (pbp->bio_children == pbp->bio_inbed) {
957 			/* Some requests succeeded. */
958 			pbp->bio_error = 0;
959 			pbp->bio_completed = pbp->bio_length;
960 		}
961 		bioq_remove(&sc->sc_inflight, pbp);
962 		/* Release delayed sync requests if possible. */
963 		g_mirror_sync_release(sc);
964 		g_io_deliver(pbp, pbp->bio_error);
965 		break;
966 	default:
967 		KASSERT(1 == 0, ("Invalid request: %u.", pbp->bio_cmd));
968 		break;
969 	}
970 }
971 
972 static void
973 g_mirror_sync_done(struct bio *bp)
974 {
975 	struct g_mirror_softc *sc;
976 
977 	G_MIRROR_LOGREQ(3, bp, "Synchronization request delivered.");
978 	sc = bp->bio_from->geom->softc;
979 	bp->bio_cflags = G_MIRROR_BIO_FLAG_SYNC;
980 	mtx_lock(&sc->sc_queue_mtx);
981 	bioq_disksort(&sc->sc_queue, bp);
982 	mtx_unlock(&sc->sc_queue_mtx);
983 	wakeup(sc);
984 }
985 
986 static void
987 g_mirror_kernel_dump(struct bio *bp)
988 {
989 	struct g_mirror_softc *sc;
990 	struct g_mirror_disk *disk;
991 	struct bio *cbp;
992 	struct g_kerneldump *gkd;
993 
994 	/*
995 	 * We configure dumping to the first component, because this component
996 	 * will be used for reading with 'prefer' balance algorithm.
997 	 * If the component with the higest priority is currently disconnected
998 	 * we will not be able to read the dump after the reboot if it will be
999 	 * connected and synchronized later. Can we do something better?
1000 	 */
1001 	sc = bp->bio_to->geom->softc;
1002 	disk = LIST_FIRST(&sc->sc_disks);
1003 
1004 	gkd = (struct g_kerneldump *)bp->bio_data;
1005 	if (gkd->length > bp->bio_to->mediasize)
1006 		gkd->length = bp->bio_to->mediasize;
1007 	cbp = g_clone_bio(bp);
1008 	if (cbp == NULL) {
1009 		g_io_deliver(bp, ENOMEM);
1010 		return;
1011 	}
1012 	cbp->bio_done = g_std_done;
1013 	g_io_request(cbp, disk->d_consumer);
1014 	G_MIRROR_DEBUG(1, "Kernel dump will go to %s.",
1015 	    g_mirror_get_diskname(disk));
1016 }
1017 
1018 static void
1019 g_mirror_flush(struct g_mirror_softc *sc, struct bio *bp)
1020 {
1021 	struct bio_queue_head queue;
1022 	struct g_mirror_disk *disk;
1023 	struct g_consumer *cp;
1024 	struct bio *cbp;
1025 
1026 	bioq_init(&queue);
1027 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1028 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1029 			continue;
1030 		cbp = g_clone_bio(bp);
1031 		if (cbp == NULL) {
1032 			for (cbp = bioq_first(&queue); cbp != NULL;
1033 			    cbp = bioq_first(&queue)) {
1034 				bioq_remove(&queue, cbp);
1035 				g_destroy_bio(cbp);
1036 			}
1037 			if (bp->bio_error == 0)
1038 				bp->bio_error = ENOMEM;
1039 			g_io_deliver(bp, bp->bio_error);
1040 			return;
1041 		}
1042 		bioq_insert_tail(&queue, cbp);
1043 		cbp->bio_done = g_std_done;
1044 		cbp->bio_caller1 = disk;
1045 		cbp->bio_to = disk->d_consumer->provider;
1046 	}
1047 	for (cbp = bioq_first(&queue); cbp != NULL; cbp = bioq_first(&queue)) {
1048 		bioq_remove(&queue, cbp);
1049 		G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1050 		disk = cbp->bio_caller1;
1051 		cbp->bio_caller1 = NULL;
1052 		cp = disk->d_consumer;
1053 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1054 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1055 		    cp->acr, cp->acw, cp->ace));
1056 		g_io_request(cbp, disk->d_consumer);
1057 	}
1058 }
1059 
1060 static void
1061 g_mirror_start(struct bio *bp)
1062 {
1063 	struct g_mirror_softc *sc;
1064 
1065 	sc = bp->bio_to->geom->softc;
1066 	/*
1067 	 * If sc == NULL or there are no valid disks, provider's error
1068 	 * should be set and g_mirror_start() should not be called at all.
1069 	 */
1070 	KASSERT(sc != NULL && sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
1071 	    ("Provider's error should be set (error=%d)(mirror=%s).",
1072 	    bp->bio_to->error, bp->bio_to->name));
1073 	G_MIRROR_LOGREQ(3, bp, "Request received.");
1074 
1075 	switch (bp->bio_cmd) {
1076 	case BIO_READ:
1077 	case BIO_WRITE:
1078 	case BIO_DELETE:
1079 		break;
1080 	case BIO_FLUSH:
1081 		g_mirror_flush(sc, bp);
1082 		return;
1083 	case BIO_GETATTR:
1084 		if (strcmp("GEOM::kerneldump", bp->bio_attribute) == 0) {
1085 			g_mirror_kernel_dump(bp);
1086 			return;
1087 		}
1088 		/* FALLTHROUGH */
1089 	default:
1090 		g_io_deliver(bp, EOPNOTSUPP);
1091 		return;
1092 	}
1093 	mtx_lock(&sc->sc_queue_mtx);
1094 	bioq_disksort(&sc->sc_queue, bp);
1095 	mtx_unlock(&sc->sc_queue_mtx);
1096 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
1097 	wakeup(sc);
1098 }
1099 
1100 /*
1101  * Return TRUE if the given request is colliding with a in-progress
1102  * synchronization request.
1103  */
1104 static int
1105 g_mirror_sync_collision(struct g_mirror_softc *sc, struct bio *bp)
1106 {
1107 	struct g_mirror_disk *disk;
1108 	struct bio *sbp;
1109 	off_t rstart, rend, sstart, send;
1110 	int i;
1111 
1112 	if (sc->sc_sync.ds_ndisks == 0)
1113 		return (0);
1114 	rstart = bp->bio_offset;
1115 	rend = bp->bio_offset + bp->bio_length;
1116 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1117 		if (disk->d_state != G_MIRROR_DISK_STATE_SYNCHRONIZING)
1118 			continue;
1119 		for (i = 0; i < g_mirror_syncreqs; i++) {
1120 			sbp = disk->d_sync.ds_bios[i];
1121 			if (sbp == NULL)
1122 				continue;
1123 			sstart = sbp->bio_offset;
1124 			send = sbp->bio_offset + sbp->bio_length;
1125 			if (rend > sstart && rstart < send)
1126 				return (1);
1127 		}
1128 	}
1129 	return (0);
1130 }
1131 
1132 /*
1133  * Return TRUE if the given sync request is colliding with a in-progress regular
1134  * request.
1135  */
1136 static int
1137 g_mirror_regular_collision(struct g_mirror_softc *sc, struct bio *sbp)
1138 {
1139 	off_t rstart, rend, sstart, send;
1140 	struct bio *bp;
1141 
1142 	if (sc->sc_sync.ds_ndisks == 0)
1143 		return (0);
1144 	sstart = sbp->bio_offset;
1145 	send = sbp->bio_offset + sbp->bio_length;
1146 	TAILQ_FOREACH(bp, &sc->sc_inflight.queue, bio_queue) {
1147 		rstart = bp->bio_offset;
1148 		rend = bp->bio_offset + bp->bio_length;
1149 		if (rend > sstart && rstart < send)
1150 			return (1);
1151 	}
1152 	return (0);
1153 }
1154 
1155 /*
1156  * Puts request onto delayed queue.
1157  */
1158 static void
1159 g_mirror_regular_delay(struct g_mirror_softc *sc, struct bio *bp)
1160 {
1161 
1162 	G_MIRROR_LOGREQ(2, bp, "Delaying request.");
1163 	bioq_insert_head(&sc->sc_regular_delayed, bp);
1164 }
1165 
1166 /*
1167  * Puts synchronization request onto delayed queue.
1168  */
1169 static void
1170 g_mirror_sync_delay(struct g_mirror_softc *sc, struct bio *bp)
1171 {
1172 
1173 	G_MIRROR_LOGREQ(2, bp, "Delaying synchronization request.");
1174 	bioq_insert_tail(&sc->sc_sync_delayed, bp);
1175 }
1176 
1177 /*
1178  * Releases delayed regular requests which don't collide anymore with sync
1179  * requests.
1180  */
1181 static void
1182 g_mirror_regular_release(struct g_mirror_softc *sc)
1183 {
1184 	struct bio *bp, *bp2;
1185 
1186 	TAILQ_FOREACH_SAFE(bp, &sc->sc_regular_delayed.queue, bio_queue, bp2) {
1187 		if (g_mirror_sync_collision(sc, bp))
1188 			continue;
1189 		bioq_remove(&sc->sc_regular_delayed, bp);
1190 		G_MIRROR_LOGREQ(2, bp, "Releasing delayed request (%p).", bp);
1191 		mtx_lock(&sc->sc_queue_mtx);
1192 		bioq_insert_head(&sc->sc_queue, bp);
1193 #if 0
1194 		/*
1195 		 * wakeup() is not needed, because this function is called from
1196 		 * the worker thread.
1197 		 */
1198 		wakeup(&sc->sc_queue);
1199 #endif
1200 		mtx_unlock(&sc->sc_queue_mtx);
1201 	}
1202 }
1203 
1204 /*
1205  * Releases delayed sync requests which don't collide anymore with regular
1206  * requests.
1207  */
1208 static void
1209 g_mirror_sync_release(struct g_mirror_softc *sc)
1210 {
1211 	struct bio *bp, *bp2;
1212 
1213 	TAILQ_FOREACH_SAFE(bp, &sc->sc_sync_delayed.queue, bio_queue, bp2) {
1214 		if (g_mirror_regular_collision(sc, bp))
1215 			continue;
1216 		bioq_remove(&sc->sc_sync_delayed, bp);
1217 		G_MIRROR_LOGREQ(2, bp,
1218 		    "Releasing delayed synchronization request.");
1219 		g_io_request(bp, bp->bio_from);
1220 	}
1221 }
1222 
1223 /*
1224  * Handle synchronization requests.
1225  * Every synchronization request is two-steps process: first, READ request is
1226  * send to active provider and then WRITE request (with read data) to the provider
1227  * beeing synchronized. When WRITE is finished, new synchronization request is
1228  * send.
1229  */
1230 static void
1231 g_mirror_sync_request(struct bio *bp)
1232 {
1233 	struct g_mirror_softc *sc;
1234 	struct g_mirror_disk *disk;
1235 
1236 	bp->bio_from->index--;
1237 	sc = bp->bio_from->geom->softc;
1238 	disk = bp->bio_from->private;
1239 	if (disk == NULL) {
1240 		sx_xunlock(&sc->sc_lock); /* Avoid recursion on sc_lock. */
1241 		g_topology_lock();
1242 		g_mirror_kill_consumer(sc, bp->bio_from);
1243 		g_topology_unlock();
1244 		free(bp->bio_data, M_MIRROR);
1245 		g_destroy_bio(bp);
1246 		sx_xlock(&sc->sc_lock);
1247 		return;
1248 	}
1249 
1250 	/*
1251 	 * Synchronization request.
1252 	 */
1253 	switch (bp->bio_cmd) {
1254 	case BIO_READ:
1255 	    {
1256 		struct g_consumer *cp;
1257 
1258 		if (bp->bio_error != 0) {
1259 			G_MIRROR_LOGREQ(0, bp,
1260 			    "Synchronization request failed (error=%d).",
1261 			    bp->bio_error);
1262 			g_destroy_bio(bp);
1263 			return;
1264 		}
1265 		G_MIRROR_LOGREQ(3, bp,
1266 		    "Synchronization request half-finished.");
1267 		bp->bio_cmd = BIO_WRITE;
1268 		bp->bio_cflags = 0;
1269 		cp = disk->d_consumer;
1270 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1271 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1272 		    cp->acr, cp->acw, cp->ace));
1273 		cp->index++;
1274 		g_io_request(bp, cp);
1275 		return;
1276 	    }
1277 	case BIO_WRITE:
1278 	    {
1279 		struct g_mirror_disk_sync *sync;
1280 		off_t offset;
1281 		void *data;
1282 		int i;
1283 
1284 		if (bp->bio_error != 0) {
1285 			G_MIRROR_LOGREQ(0, bp,
1286 			    "Synchronization request failed (error=%d).",
1287 			    bp->bio_error);
1288 			g_destroy_bio(bp);
1289 			sc->sc_bump_id |= G_MIRROR_BUMP_GENID;
1290 			g_mirror_event_send(disk,
1291 			    G_MIRROR_DISK_STATE_DISCONNECTED,
1292 			    G_MIRROR_EVENT_DONTWAIT);
1293 			return;
1294 		}
1295 		G_MIRROR_LOGREQ(3, bp, "Synchronization request finished.");
1296 		sync = &disk->d_sync;
1297 		if (sync->ds_offset == sc->sc_mediasize ||
1298 		    sync->ds_consumer == NULL ||
1299 		    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1300 			/* Don't send more synchronization requests. */
1301 			sync->ds_inflight--;
1302 			if (sync->ds_bios != NULL) {
1303 				i = (int)(uintptr_t)bp->bio_caller1;
1304 				sync->ds_bios[i] = NULL;
1305 			}
1306 			free(bp->bio_data, M_MIRROR);
1307 			g_destroy_bio(bp);
1308 			if (sync->ds_inflight > 0)
1309 				return;
1310 			if (sync->ds_consumer == NULL ||
1311 			    (sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1312 				return;
1313 			}
1314 			/* Disk up-to-date, activate it. */
1315 			g_mirror_event_send(disk, G_MIRROR_DISK_STATE_ACTIVE,
1316 			    G_MIRROR_EVENT_DONTWAIT);
1317 			return;
1318 		}
1319 
1320 		/* Send next synchronization request. */
1321 		data = bp->bio_data;
1322 		bzero(bp, sizeof(*bp));
1323 		bp->bio_cmd = BIO_READ;
1324 		bp->bio_offset = sync->ds_offset;
1325 		bp->bio_length = MIN(MAXPHYS, sc->sc_mediasize - bp->bio_offset);
1326 		sync->ds_offset += bp->bio_length;
1327 		bp->bio_done = g_mirror_sync_done;
1328 		bp->bio_data = data;
1329 		bp->bio_from = sync->ds_consumer;
1330 		bp->bio_to = sc->sc_provider;
1331 		G_MIRROR_LOGREQ(3, bp, "Sending synchronization request.");
1332 		sync->ds_consumer->index++;
1333 		/*
1334 		 * Delay the request if it is colliding with a regular request.
1335 		 */
1336 		if (g_mirror_regular_collision(sc, bp))
1337 			g_mirror_sync_delay(sc, bp);
1338 		else
1339 			g_io_request(bp, sync->ds_consumer);
1340 
1341 		/* Release delayed requests if possible. */
1342 		g_mirror_regular_release(sc);
1343 
1344 		/* Find the smallest offset */
1345 		offset = sc->sc_mediasize;
1346 		for (i = 0; i < g_mirror_syncreqs; i++) {
1347 			bp = sync->ds_bios[i];
1348 			if (bp->bio_offset < offset)
1349 				offset = bp->bio_offset;
1350 		}
1351 		if (sync->ds_offset_done + (MAXPHYS * 100) < offset) {
1352 			/* Update offset_done on every 100 blocks. */
1353 			sync->ds_offset_done = offset;
1354 			g_mirror_update_metadata(disk);
1355 		}
1356 		return;
1357 	    }
1358 	default:
1359 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1360 		    bp->bio_cmd, sc->sc_name));
1361 		break;
1362 	}
1363 }
1364 
1365 static void
1366 g_mirror_request_prefer(struct g_mirror_softc *sc, struct bio *bp)
1367 {
1368 	struct g_mirror_disk *disk;
1369 	struct g_consumer *cp;
1370 	struct bio *cbp;
1371 
1372 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1373 		if (disk->d_state == G_MIRROR_DISK_STATE_ACTIVE)
1374 			break;
1375 	}
1376 	if (disk == NULL) {
1377 		if (bp->bio_error == 0)
1378 			bp->bio_error = ENXIO;
1379 		g_io_deliver(bp, bp->bio_error);
1380 		return;
1381 	}
1382 	cbp = g_clone_bio(bp);
1383 	if (cbp == NULL) {
1384 		if (bp->bio_error == 0)
1385 			bp->bio_error = ENOMEM;
1386 		g_io_deliver(bp, bp->bio_error);
1387 		return;
1388 	}
1389 	/*
1390 	 * Fill in the component buf structure.
1391 	 */
1392 	cp = disk->d_consumer;
1393 	cbp->bio_done = g_mirror_done;
1394 	cbp->bio_to = cp->provider;
1395 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1396 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1397 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1398 	    cp->acw, cp->ace));
1399 	cp->index++;
1400 	g_io_request(cbp, cp);
1401 }
1402 
1403 static void
1404 g_mirror_request_round_robin(struct g_mirror_softc *sc, struct bio *bp)
1405 {
1406 	struct g_mirror_disk *disk;
1407 	struct g_consumer *cp;
1408 	struct bio *cbp;
1409 
1410 	disk = g_mirror_get_disk(sc);
1411 	if (disk == NULL) {
1412 		if (bp->bio_error == 0)
1413 			bp->bio_error = ENXIO;
1414 		g_io_deliver(bp, bp->bio_error);
1415 		return;
1416 	}
1417 	cbp = g_clone_bio(bp);
1418 	if (cbp == NULL) {
1419 		if (bp->bio_error == 0)
1420 			bp->bio_error = ENOMEM;
1421 		g_io_deliver(bp, bp->bio_error);
1422 		return;
1423 	}
1424 	/*
1425 	 * Fill in the component buf structure.
1426 	 */
1427 	cp = disk->d_consumer;
1428 	cbp->bio_done = g_mirror_done;
1429 	cbp->bio_to = cp->provider;
1430 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1431 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1432 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1433 	    cp->acw, cp->ace));
1434 	cp->index++;
1435 	g_io_request(cbp, cp);
1436 }
1437 
1438 #define TRACK_SIZE  (1 * 1024 * 1024)
1439 #define LOAD_SCALE	256
1440 #define ABS(x)		(((x) >= 0) ? (x) : (-(x)))
1441 
1442 static void
1443 g_mirror_request_load(struct g_mirror_softc *sc, struct bio *bp)
1444 {
1445 	struct g_mirror_disk *disk, *dp;
1446 	struct g_consumer *cp;
1447 	struct bio *cbp;
1448 	int prio, best;
1449 
1450 	/* Find a disk with the smallest load. */
1451 	disk = NULL;
1452 	best = INT_MAX;
1453 	LIST_FOREACH(dp, &sc->sc_disks, d_next) {
1454 		if (dp->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1455 			continue;
1456 		prio = dp->load;
1457 		/* If disk head is precisely in position - highly prefer it. */
1458 		if (dp->d_last_offset == bp->bio_offset)
1459 			prio -= 2 * LOAD_SCALE;
1460 		else
1461 		/* If disk head is close to position - prefer it. */
1462 		if (ABS(dp->d_last_offset - bp->bio_offset) < TRACK_SIZE)
1463 			prio -= 1 * LOAD_SCALE;
1464 		if (prio <= best) {
1465 			disk = dp;
1466 			best = prio;
1467 		}
1468 	}
1469 	KASSERT(disk != NULL, ("NULL disk for %s.", sc->sc_name));
1470 	cbp = g_clone_bio(bp);
1471 	if (cbp == NULL) {
1472 		if (bp->bio_error == 0)
1473 			bp->bio_error = ENOMEM;
1474 		g_io_deliver(bp, bp->bio_error);
1475 		return;
1476 	}
1477 	/*
1478 	 * Fill in the component buf structure.
1479 	 */
1480 	cp = disk->d_consumer;
1481 	cbp->bio_done = g_mirror_done;
1482 	cbp->bio_to = cp->provider;
1483 	G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1484 	KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1485 	    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name, cp->acr,
1486 	    cp->acw, cp->ace));
1487 	cp->index++;
1488 	/* Remember last head position */
1489 	disk->d_last_offset = bp->bio_offset + bp->bio_length;
1490 	/* Update loads. */
1491 	LIST_FOREACH(dp, &sc->sc_disks, d_next) {
1492 		dp->load = (dp->d_consumer->index * LOAD_SCALE +
1493 		    dp->load * 7) / 8;
1494 	}
1495 	g_io_request(cbp, cp);
1496 }
1497 
1498 static void
1499 g_mirror_request_split(struct g_mirror_softc *sc, struct bio *bp)
1500 {
1501 	struct bio_queue_head queue;
1502 	struct g_mirror_disk *disk;
1503 	struct g_consumer *cp;
1504 	struct bio *cbp;
1505 	off_t left, mod, offset, slice;
1506 	u_char *data;
1507 	u_int ndisks;
1508 
1509 	if (bp->bio_length <= sc->sc_slice) {
1510 		g_mirror_request_round_robin(sc, bp);
1511 		return;
1512 	}
1513 	ndisks = g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE);
1514 	slice = bp->bio_length / ndisks;
1515 	mod = slice % sc->sc_provider->sectorsize;
1516 	if (mod != 0)
1517 		slice += sc->sc_provider->sectorsize - mod;
1518 	/*
1519 	 * Allocate all bios before sending any request, so we can
1520 	 * return ENOMEM in nice and clean way.
1521 	 */
1522 	left = bp->bio_length;
1523 	offset = bp->bio_offset;
1524 	data = bp->bio_data;
1525 	bioq_init(&queue);
1526 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1527 		if (disk->d_state != G_MIRROR_DISK_STATE_ACTIVE)
1528 			continue;
1529 		cbp = g_clone_bio(bp);
1530 		if (cbp == NULL) {
1531 			for (cbp = bioq_first(&queue); cbp != NULL;
1532 			    cbp = bioq_first(&queue)) {
1533 				bioq_remove(&queue, cbp);
1534 				g_destroy_bio(cbp);
1535 			}
1536 			if (bp->bio_error == 0)
1537 				bp->bio_error = ENOMEM;
1538 			g_io_deliver(bp, bp->bio_error);
1539 			return;
1540 		}
1541 		bioq_insert_tail(&queue, cbp);
1542 		cbp->bio_done = g_mirror_done;
1543 		cbp->bio_caller1 = disk;
1544 		cbp->bio_to = disk->d_consumer->provider;
1545 		cbp->bio_offset = offset;
1546 		cbp->bio_data = data;
1547 		cbp->bio_length = MIN(left, slice);
1548 		left -= cbp->bio_length;
1549 		if (left == 0)
1550 			break;
1551 		offset += cbp->bio_length;
1552 		data += cbp->bio_length;
1553 	}
1554 	for (cbp = bioq_first(&queue); cbp != NULL; cbp = bioq_first(&queue)) {
1555 		bioq_remove(&queue, cbp);
1556 		G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1557 		disk = cbp->bio_caller1;
1558 		cbp->bio_caller1 = NULL;
1559 		cp = disk->d_consumer;
1560 		KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1561 		    ("Consumer %s not opened (r%dw%de%d).", cp->provider->name,
1562 		    cp->acr, cp->acw, cp->ace));
1563 		disk->d_consumer->index++;
1564 		g_io_request(cbp, disk->d_consumer);
1565 	}
1566 }
1567 
1568 static void
1569 g_mirror_register_request(struct bio *bp)
1570 {
1571 	struct g_mirror_softc *sc;
1572 
1573 	sc = bp->bio_to->geom->softc;
1574 	switch (bp->bio_cmd) {
1575 	case BIO_READ:
1576 		switch (sc->sc_balance) {
1577 		case G_MIRROR_BALANCE_LOAD:
1578 			g_mirror_request_load(sc, bp);
1579 			break;
1580 		case G_MIRROR_BALANCE_PREFER:
1581 			g_mirror_request_prefer(sc, bp);
1582 			break;
1583 		case G_MIRROR_BALANCE_ROUND_ROBIN:
1584 			g_mirror_request_round_robin(sc, bp);
1585 			break;
1586 		case G_MIRROR_BALANCE_SPLIT:
1587 			g_mirror_request_split(sc, bp);
1588 			break;
1589 		}
1590 		return;
1591 	case BIO_WRITE:
1592 	case BIO_DELETE:
1593 	    {
1594 		struct g_mirror_disk *disk;
1595 		struct g_mirror_disk_sync *sync;
1596 		struct bio_queue_head queue;
1597 		struct g_consumer *cp;
1598 		struct bio *cbp;
1599 
1600 		/*
1601 		 * Delay the request if it is colliding with a synchronization
1602 		 * request.
1603 		 */
1604 		if (g_mirror_sync_collision(sc, bp)) {
1605 			g_mirror_regular_delay(sc, bp);
1606 			return;
1607 		}
1608 
1609 		if (sc->sc_idle)
1610 			g_mirror_unidle(sc);
1611 		else
1612 			sc->sc_last_write = time_uptime;
1613 
1614 		/*
1615 		 * Allocate all bios before sending any request, so we can
1616 		 * return ENOMEM in nice and clean way.
1617 		 */
1618 		bioq_init(&queue);
1619 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
1620 			sync = &disk->d_sync;
1621 			switch (disk->d_state) {
1622 			case G_MIRROR_DISK_STATE_ACTIVE:
1623 				break;
1624 			case G_MIRROR_DISK_STATE_SYNCHRONIZING:
1625 				if (bp->bio_offset >= sync->ds_offset)
1626 					continue;
1627 				break;
1628 			default:
1629 				continue;
1630 			}
1631 			cbp = g_clone_bio(bp);
1632 			if (cbp == NULL) {
1633 				for (cbp = bioq_first(&queue); cbp != NULL;
1634 				    cbp = bioq_first(&queue)) {
1635 					bioq_remove(&queue, cbp);
1636 					g_destroy_bio(cbp);
1637 				}
1638 				if (bp->bio_error == 0)
1639 					bp->bio_error = ENOMEM;
1640 				g_io_deliver(bp, bp->bio_error);
1641 				return;
1642 			}
1643 			bioq_insert_tail(&queue, cbp);
1644 			cbp->bio_done = g_mirror_done;
1645 			cp = disk->d_consumer;
1646 			cbp->bio_caller1 = cp;
1647 			cbp->bio_to = cp->provider;
1648 			KASSERT(cp->acr >= 1 && cp->acw >= 1 && cp->ace >= 1,
1649 			    ("Consumer %s not opened (r%dw%de%d).",
1650 			    cp->provider->name, cp->acr, cp->acw, cp->ace));
1651 		}
1652 		for (cbp = bioq_first(&queue); cbp != NULL;
1653 		    cbp = bioq_first(&queue)) {
1654 			bioq_remove(&queue, cbp);
1655 			G_MIRROR_LOGREQ(3, cbp, "Sending request.");
1656 			cp = cbp->bio_caller1;
1657 			cbp->bio_caller1 = NULL;
1658 			cp->index++;
1659 			sc->sc_writes++;
1660 			g_io_request(cbp, cp);
1661 		}
1662 		/*
1663 		 * Put request onto inflight queue, so we can check if new
1664 		 * synchronization requests don't collide with it.
1665 		 */
1666 		bioq_insert_tail(&sc->sc_inflight, bp);
1667 		/*
1668 		 * Bump syncid on first write.
1669 		 */
1670 		if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0) {
1671 			sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
1672 			g_mirror_bump_syncid(sc);
1673 		}
1674 		return;
1675 	    }
1676 	default:
1677 		KASSERT(1 == 0, ("Invalid command here: %u (device=%s)",
1678 		    bp->bio_cmd, sc->sc_name));
1679 		break;
1680 	}
1681 }
1682 
1683 static int
1684 g_mirror_can_destroy(struct g_mirror_softc *sc)
1685 {
1686 	struct g_geom *gp;
1687 	struct g_consumer *cp;
1688 
1689 	g_topology_assert();
1690 	gp = sc->sc_geom;
1691 	if (gp->softc == NULL)
1692 		return (1);
1693 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1694 		if (g_mirror_is_busy(sc, cp))
1695 			return (0);
1696 	}
1697 	gp = sc->sc_sync.ds_geom;
1698 	LIST_FOREACH(cp, &gp->consumer, consumer) {
1699 		if (g_mirror_is_busy(sc, cp))
1700 			return (0);
1701 	}
1702 	G_MIRROR_DEBUG(2, "No I/O requests for %s, it can be destroyed.",
1703 	    sc->sc_name);
1704 	return (1);
1705 }
1706 
1707 static int
1708 g_mirror_try_destroy(struct g_mirror_softc *sc)
1709 {
1710 
1711 	if (sc->sc_rootmount != NULL) {
1712 		G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p", __LINE__,
1713 		    sc->sc_rootmount);
1714 		root_mount_rel(sc->sc_rootmount);
1715 		sc->sc_rootmount = NULL;
1716 	}
1717 	g_topology_lock();
1718 	if (!g_mirror_can_destroy(sc)) {
1719 		g_topology_unlock();
1720 		return (0);
1721 	}
1722 	sc->sc_geom->softc = NULL;
1723 	sc->sc_sync.ds_geom->softc = NULL;
1724 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_WAIT) != 0) {
1725 		g_topology_unlock();
1726 		G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1727 		    &sc->sc_worker);
1728 		/* Unlock sc_lock here, as it can be destroyed after wakeup. */
1729 		sx_xunlock(&sc->sc_lock);
1730 		wakeup(&sc->sc_worker);
1731 		sc->sc_worker = NULL;
1732 	} else {
1733 		g_topology_unlock();
1734 		g_mirror_destroy_device(sc);
1735 		free(sc, M_MIRROR);
1736 	}
1737 	return (1);
1738 }
1739 
1740 /*
1741  * Worker thread.
1742  */
1743 static void
1744 g_mirror_worker(void *arg)
1745 {
1746 	struct g_mirror_softc *sc;
1747 	struct g_mirror_event *ep;
1748 	struct bio *bp;
1749 	int timeout;
1750 
1751 	sc = arg;
1752 	thread_lock(curthread);
1753 	sched_prio(curthread, PRIBIO);
1754 	thread_unlock(curthread);
1755 
1756 	sx_xlock(&sc->sc_lock);
1757 	for (;;) {
1758 		G_MIRROR_DEBUG(5, "%s: Let's see...", __func__);
1759 		/*
1760 		 * First take a look at events.
1761 		 * This is important to handle events before any I/O requests.
1762 		 */
1763 		ep = g_mirror_event_get(sc);
1764 		if (ep != NULL) {
1765 			g_mirror_event_remove(sc, ep);
1766 			if ((ep->e_flags & G_MIRROR_EVENT_DEVICE) != 0) {
1767 				/* Update only device status. */
1768 				G_MIRROR_DEBUG(3,
1769 				    "Running event for device %s.",
1770 				    sc->sc_name);
1771 				ep->e_error = 0;
1772 				g_mirror_update_device(sc, 1);
1773 			} else {
1774 				/* Update disk status. */
1775 				G_MIRROR_DEBUG(3, "Running event for disk %s.",
1776 				     g_mirror_get_diskname(ep->e_disk));
1777 				ep->e_error = g_mirror_update_disk(ep->e_disk,
1778 				    ep->e_state);
1779 				if (ep->e_error == 0)
1780 					g_mirror_update_device(sc, 0);
1781 			}
1782 			if ((ep->e_flags & G_MIRROR_EVENT_DONTWAIT) != 0) {
1783 				KASSERT(ep->e_error == 0,
1784 				    ("Error cannot be handled."));
1785 				g_mirror_event_free(ep);
1786 			} else {
1787 				ep->e_flags |= G_MIRROR_EVENT_DONE;
1788 				G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__,
1789 				    ep);
1790 				mtx_lock(&sc->sc_events_mtx);
1791 				wakeup(ep);
1792 				mtx_unlock(&sc->sc_events_mtx);
1793 			}
1794 			if ((sc->sc_flags &
1795 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1796 				if (g_mirror_try_destroy(sc)) {
1797 					curthread->td_pflags &= ~TDP_GEOM;
1798 					G_MIRROR_DEBUG(1, "Thread exiting.");
1799 					kproc_exit(0);
1800 				}
1801 			}
1802 			G_MIRROR_DEBUG(5, "%s: I'm here 1.", __func__);
1803 			continue;
1804 		}
1805 		/*
1806 		 * Check if we can mark array as CLEAN and if we can't take
1807 		 * how much seconds should we wait.
1808 		 */
1809 		timeout = g_mirror_idle(sc, -1);
1810 		/*
1811 		 * Now I/O requests.
1812 		 */
1813 		/* Get first request from the queue. */
1814 		mtx_lock(&sc->sc_queue_mtx);
1815 		bp = bioq_first(&sc->sc_queue);
1816 		if (bp == NULL) {
1817 			if ((sc->sc_flags &
1818 			    G_MIRROR_DEVICE_FLAG_DESTROY) != 0) {
1819 				mtx_unlock(&sc->sc_queue_mtx);
1820 				if (g_mirror_try_destroy(sc)) {
1821 					curthread->td_pflags &= ~TDP_GEOM;
1822 					G_MIRROR_DEBUG(1, "Thread exiting.");
1823 					kproc_exit(0);
1824 				}
1825 				mtx_lock(&sc->sc_queue_mtx);
1826 			}
1827 			sx_xunlock(&sc->sc_lock);
1828 			/*
1829 			 * XXX: We can miss an event here, because an event
1830 			 *      can be added without sx-device-lock and without
1831 			 *      mtx-queue-lock. Maybe I should just stop using
1832 			 *      dedicated mutex for events synchronization and
1833 			 *      stick with the queue lock?
1834 			 *      The event will hang here until next I/O request
1835 			 *      or next event is received.
1836 			 */
1837 			MSLEEP(sc, &sc->sc_queue_mtx, PRIBIO | PDROP, "m:w1",
1838 			    timeout * hz);
1839 			sx_xlock(&sc->sc_lock);
1840 			G_MIRROR_DEBUG(5, "%s: I'm here 4.", __func__);
1841 			continue;
1842 		}
1843 		bioq_remove(&sc->sc_queue, bp);
1844 		mtx_unlock(&sc->sc_queue_mtx);
1845 
1846 		if (bp->bio_from->geom == sc->sc_sync.ds_geom &&
1847 		    (bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0) {
1848 			g_mirror_sync_request(bp);	/* READ */
1849 		} else if (bp->bio_to != sc->sc_provider) {
1850 			if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_REGULAR) != 0)
1851 				g_mirror_regular_request(bp);
1852 			else if ((bp->bio_cflags & G_MIRROR_BIO_FLAG_SYNC) != 0)
1853 				g_mirror_sync_request(bp);	/* WRITE */
1854 			else {
1855 				KASSERT(0,
1856 				    ("Invalid request cflags=0x%hhx to=%s.",
1857 				    bp->bio_cflags, bp->bio_to->name));
1858 			}
1859 		} else {
1860 			g_mirror_register_request(bp);
1861 		}
1862 		G_MIRROR_DEBUG(5, "%s: I'm here 9.", __func__);
1863 	}
1864 }
1865 
1866 static void
1867 g_mirror_update_idle(struct g_mirror_softc *sc, struct g_mirror_disk *disk)
1868 {
1869 
1870 	sx_assert(&sc->sc_lock, SX_LOCKED);
1871 
1872 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
1873 		return;
1874 	if (!sc->sc_idle && (disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) == 0) {
1875 		G_MIRROR_DEBUG(1, "Disk %s (device %s) marked as dirty.",
1876 		    g_mirror_get_diskname(disk), sc->sc_name);
1877 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1878 	} else if (sc->sc_idle &&
1879 	    (disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
1880 		G_MIRROR_DEBUG(1, "Disk %s (device %s) marked as clean.",
1881 		    g_mirror_get_diskname(disk), sc->sc_name);
1882 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
1883 	}
1884 }
1885 
1886 static void
1887 g_mirror_sync_start(struct g_mirror_disk *disk)
1888 {
1889 	struct g_mirror_softc *sc;
1890 	struct g_consumer *cp;
1891 	struct bio *bp;
1892 	int error, i;
1893 
1894 	g_topology_assert_not();
1895 	sc = disk->d_softc;
1896 	sx_assert(&sc->sc_lock, SX_LOCKED);
1897 
1898 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
1899 	    ("Disk %s is not marked for synchronization.",
1900 	    g_mirror_get_diskname(disk)));
1901 	KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
1902 	    ("Device not in RUNNING state (%s, %u).", sc->sc_name,
1903 	    sc->sc_state));
1904 
1905 	sx_xunlock(&sc->sc_lock);
1906 	g_topology_lock();
1907 	cp = g_new_consumer(sc->sc_sync.ds_geom);
1908 	error = g_attach(cp, sc->sc_provider);
1909 	KASSERT(error == 0,
1910 	    ("Cannot attach to %s (error=%d).", sc->sc_name, error));
1911 	error = g_access(cp, 1, 0, 0);
1912 	KASSERT(error == 0, ("Cannot open %s (error=%d).", sc->sc_name, error));
1913 	g_topology_unlock();
1914 	sx_xlock(&sc->sc_lock);
1915 
1916 	G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s.", sc->sc_name,
1917 	    g_mirror_get_diskname(disk));
1918 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) == 0)
1919 		disk->d_flags |= G_MIRROR_DISK_FLAG_DIRTY;
1920 	KASSERT(disk->d_sync.ds_consumer == NULL,
1921 	    ("Sync consumer already exists (device=%s, disk=%s).",
1922 	    sc->sc_name, g_mirror_get_diskname(disk)));
1923 
1924 	disk->d_sync.ds_consumer = cp;
1925 	disk->d_sync.ds_consumer->private = disk;
1926 	disk->d_sync.ds_consumer->index = 0;
1927 
1928 	/*
1929 	 * Allocate memory for synchronization bios and initialize them.
1930 	 */
1931 	disk->d_sync.ds_bios = malloc(sizeof(struct bio *) * g_mirror_syncreqs,
1932 	    M_MIRROR, M_WAITOK);
1933 	for (i = 0; i < g_mirror_syncreqs; i++) {
1934 		bp = g_alloc_bio();
1935 		disk->d_sync.ds_bios[i] = bp;
1936 		bp->bio_parent = NULL;
1937 		bp->bio_cmd = BIO_READ;
1938 		bp->bio_data = malloc(MAXPHYS, M_MIRROR, M_WAITOK);
1939 		bp->bio_cflags = 0;
1940 		bp->bio_offset = disk->d_sync.ds_offset;
1941 		bp->bio_length = MIN(MAXPHYS, sc->sc_mediasize - bp->bio_offset);
1942 		disk->d_sync.ds_offset += bp->bio_length;
1943 		bp->bio_done = g_mirror_sync_done;
1944 		bp->bio_from = disk->d_sync.ds_consumer;
1945 		bp->bio_to = sc->sc_provider;
1946 		bp->bio_caller1 = (void *)(uintptr_t)i;
1947 	}
1948 
1949 	/* Increase the number of disks in SYNCHRONIZING state. */
1950 	sc->sc_sync.ds_ndisks++;
1951 	/* Set the number of in-flight synchronization requests. */
1952 	disk->d_sync.ds_inflight = g_mirror_syncreqs;
1953 
1954 	/*
1955 	 * Fire off first synchronization requests.
1956 	 */
1957 	for (i = 0; i < g_mirror_syncreqs; i++) {
1958 		bp = disk->d_sync.ds_bios[i];
1959 		G_MIRROR_LOGREQ(3, bp, "Sending synchronization request.");
1960 		disk->d_sync.ds_consumer->index++;
1961 		/*
1962 		 * Delay the request if it is colliding with a regular request.
1963 		 */
1964 		if (g_mirror_regular_collision(sc, bp))
1965 			g_mirror_sync_delay(sc, bp);
1966 		else
1967 			g_io_request(bp, disk->d_sync.ds_consumer);
1968 	}
1969 }
1970 
1971 /*
1972  * Stop synchronization process.
1973  * type: 0 - synchronization finished
1974  *       1 - synchronization stopped
1975  */
1976 static void
1977 g_mirror_sync_stop(struct g_mirror_disk *disk, int type)
1978 {
1979 	struct g_mirror_softc *sc;
1980 	struct g_consumer *cp;
1981 
1982 	g_topology_assert_not();
1983 	sc = disk->d_softc;
1984 	sx_assert(&sc->sc_lock, SX_LOCKED);
1985 
1986 	KASSERT(disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
1987 	    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
1988 	    g_mirror_disk_state2str(disk->d_state)));
1989 	if (disk->d_sync.ds_consumer == NULL)
1990 		return;
1991 
1992 	if (type == 0) {
1993 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s finished.",
1994 		    sc->sc_name, g_mirror_get_diskname(disk));
1995 	} else /* if (type == 1) */ {
1996 		G_MIRROR_DEBUG(0, "Device %s: rebuilding provider %s stopped.",
1997 		    sc->sc_name, g_mirror_get_diskname(disk));
1998 	}
1999 	free(disk->d_sync.ds_bios, M_MIRROR);
2000 	disk->d_sync.ds_bios = NULL;
2001 	cp = disk->d_sync.ds_consumer;
2002 	disk->d_sync.ds_consumer = NULL;
2003 	disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2004 	sc->sc_sync.ds_ndisks--;
2005 	sx_xunlock(&sc->sc_lock); /* Avoid recursion on sc_lock. */
2006 	g_topology_lock();
2007 	g_mirror_kill_consumer(sc, cp);
2008 	g_topology_unlock();
2009 	sx_xlock(&sc->sc_lock);
2010 }
2011 
2012 static void
2013 g_mirror_launch_provider(struct g_mirror_softc *sc)
2014 {
2015 	struct g_mirror_disk *disk;
2016 	struct g_provider *pp;
2017 
2018 	sx_assert(&sc->sc_lock, SX_LOCKED);
2019 
2020 	g_topology_lock();
2021 	pp = g_new_providerf(sc->sc_geom, "mirror/%s", sc->sc_name);
2022 	pp->mediasize = sc->sc_mediasize;
2023 	pp->sectorsize = sc->sc_sectorsize;
2024 	pp->stripesize = 0;
2025 	pp->stripeoffset = 0;
2026 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2027 		if (disk->d_consumer && disk->d_consumer->provider &&
2028 		    disk->d_consumer->provider->stripesize > pp->stripesize) {
2029 			pp->stripesize = disk->d_consumer->provider->stripesize;
2030 			pp->stripeoffset = disk->d_consumer->provider->stripeoffset;
2031 		}
2032 	}
2033 	sc->sc_provider = pp;
2034 	g_error_provider(pp, 0);
2035 	g_topology_unlock();
2036 	G_MIRROR_DEBUG(0, "Device %s launched (%u/%u).", pp->name,
2037 	    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE), sc->sc_ndisks);
2038 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2039 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
2040 			g_mirror_sync_start(disk);
2041 	}
2042 }
2043 
2044 static void
2045 g_mirror_destroy_provider(struct g_mirror_softc *sc)
2046 {
2047 	struct g_mirror_disk *disk;
2048 	struct bio *bp;
2049 
2050 	g_topology_assert_not();
2051 	KASSERT(sc->sc_provider != NULL, ("NULL provider (device=%s).",
2052 	    sc->sc_name));
2053 
2054 	g_topology_lock();
2055 	g_error_provider(sc->sc_provider, ENXIO);
2056 	mtx_lock(&sc->sc_queue_mtx);
2057 	while ((bp = bioq_first(&sc->sc_queue)) != NULL) {
2058 		bioq_remove(&sc->sc_queue, bp);
2059 		g_io_deliver(bp, ENXIO);
2060 	}
2061 	mtx_unlock(&sc->sc_queue_mtx);
2062 	G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.", sc->sc_name,
2063 	    sc->sc_provider->name);
2064 	sc->sc_provider->flags |= G_PF_WITHER;
2065 	g_orphan_provider(sc->sc_provider, ENXIO);
2066 	g_topology_unlock();
2067 	sc->sc_provider = NULL;
2068 	LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2069 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING)
2070 			g_mirror_sync_stop(disk, 1);
2071 	}
2072 }
2073 
2074 static void
2075 g_mirror_go(void *arg)
2076 {
2077 	struct g_mirror_softc *sc;
2078 
2079 	sc = arg;
2080 	G_MIRROR_DEBUG(0, "Force device %s start due to timeout.", sc->sc_name);
2081 	g_mirror_event_send(sc, 0,
2082 	    G_MIRROR_EVENT_DONTWAIT | G_MIRROR_EVENT_DEVICE);
2083 }
2084 
2085 static u_int
2086 g_mirror_determine_state(struct g_mirror_disk *disk)
2087 {
2088 	struct g_mirror_softc *sc;
2089 	u_int state;
2090 
2091 	sc = disk->d_softc;
2092 	if (sc->sc_syncid == disk->d_sync.ds_syncid) {
2093 		if ((disk->d_flags &
2094 		    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
2095 			/* Disk does not need synchronization. */
2096 			state = G_MIRROR_DISK_STATE_ACTIVE;
2097 		} else {
2098 			if ((sc->sc_flags &
2099 			     G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
2100 			    (disk->d_flags &
2101 			     G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
2102 				/*
2103 				 * We can start synchronization from
2104 				 * the stored offset.
2105 				 */
2106 				state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
2107 			} else {
2108 				state = G_MIRROR_DISK_STATE_STALE;
2109 			}
2110 		}
2111 	} else if (disk->d_sync.ds_syncid < sc->sc_syncid) {
2112 		/*
2113 		 * Reset all synchronization data for this disk,
2114 		 * because if it even was synchronized, it was
2115 		 * synchronized to disks with different syncid.
2116 		 */
2117 		disk->d_flags |= G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2118 		disk->d_sync.ds_offset = 0;
2119 		disk->d_sync.ds_offset_done = 0;
2120 		disk->d_sync.ds_syncid = sc->sc_syncid;
2121 		if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) == 0 ||
2122 		    (disk->d_flags & G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0) {
2123 			state = G_MIRROR_DISK_STATE_SYNCHRONIZING;
2124 		} else {
2125 			state = G_MIRROR_DISK_STATE_STALE;
2126 		}
2127 	} else /* if (sc->sc_syncid < disk->d_sync.ds_syncid) */ {
2128 		/*
2129 		 * Not good, NOT GOOD!
2130 		 * It means that mirror was started on stale disks
2131 		 * and more fresh disk just arrive.
2132 		 * If there were writes, mirror is broken, sorry.
2133 		 * I think the best choice here is don't touch
2134 		 * this disk and inform the user loudly.
2135 		 */
2136 		G_MIRROR_DEBUG(0, "Device %s was started before the freshest "
2137 		    "disk (%s) arrives!! It will not be connected to the "
2138 		    "running device.", sc->sc_name,
2139 		    g_mirror_get_diskname(disk));
2140 		g_mirror_destroy_disk(disk);
2141 		state = G_MIRROR_DISK_STATE_NONE;
2142 		/* Return immediately, because disk was destroyed. */
2143 		return (state);
2144 	}
2145 	G_MIRROR_DEBUG(3, "State for %s disk: %s.",
2146 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(state));
2147 	return (state);
2148 }
2149 
2150 /*
2151  * Update device state.
2152  */
2153 static void
2154 g_mirror_update_device(struct g_mirror_softc *sc, boolean_t force)
2155 {
2156 	struct g_mirror_disk *disk;
2157 	u_int state;
2158 
2159 	sx_assert(&sc->sc_lock, SX_XLOCKED);
2160 
2161 	switch (sc->sc_state) {
2162 	case G_MIRROR_DEVICE_STATE_STARTING:
2163 	    {
2164 		struct g_mirror_disk *pdisk, *tdisk;
2165 		u_int dirty, ndisks, genid, syncid;
2166 
2167 		KASSERT(sc->sc_provider == NULL,
2168 		    ("Non-NULL provider in STARTING state (%s).", sc->sc_name));
2169 		/*
2170 		 * Are we ready? We are, if all disks are connected or
2171 		 * if we have any disks and 'force' is true.
2172 		 */
2173 		ndisks = g_mirror_ndisks(sc, -1);
2174 		if (sc->sc_ndisks == ndisks || (force && ndisks > 0)) {
2175 			;
2176 		} else if (ndisks == 0) {
2177 			/*
2178 			 * Disks went down in starting phase, so destroy
2179 			 * device.
2180 			 */
2181 			callout_drain(&sc->sc_callout);
2182 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2183 			G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p", __LINE__,
2184 			    sc->sc_rootmount);
2185 			root_mount_rel(sc->sc_rootmount);
2186 			sc->sc_rootmount = NULL;
2187 			return;
2188 		} else {
2189 			return;
2190 		}
2191 
2192 		/*
2193 		 * Activate all disks with the biggest syncid.
2194 		 */
2195 		if (force) {
2196 			/*
2197 			 * If 'force' is true, we have been called due to
2198 			 * timeout, so don't bother canceling timeout.
2199 			 */
2200 			ndisks = 0;
2201 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2202 				if ((disk->d_flags &
2203 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) == 0) {
2204 					ndisks++;
2205 				}
2206 			}
2207 			if (ndisks == 0) {
2208 				/* No valid disks found, destroy device. */
2209 				sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2210 				G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p",
2211 				    __LINE__, sc->sc_rootmount);
2212 				root_mount_rel(sc->sc_rootmount);
2213 				sc->sc_rootmount = NULL;
2214 				return;
2215 			}
2216 		} else {
2217 			/* Cancel timeout. */
2218 			callout_drain(&sc->sc_callout);
2219 		}
2220 
2221 		/*
2222 		 * Find the biggest genid.
2223 		 */
2224 		genid = 0;
2225 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2226 			if (disk->d_genid > genid)
2227 				genid = disk->d_genid;
2228 		}
2229 		sc->sc_genid = genid;
2230 		/*
2231 		 * Remove all disks without the biggest genid.
2232 		 */
2233 		LIST_FOREACH_SAFE(disk, &sc->sc_disks, d_next, tdisk) {
2234 			if (disk->d_genid < genid) {
2235 				G_MIRROR_DEBUG(0,
2236 				    "Component %s (device %s) broken, skipping.",
2237 				    g_mirror_get_diskname(disk), sc->sc_name);
2238 				g_mirror_destroy_disk(disk);
2239 			}
2240 		}
2241 
2242 		/*
2243 		 * Find the biggest syncid.
2244 		 */
2245 		syncid = 0;
2246 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2247 			if (disk->d_sync.ds_syncid > syncid)
2248 				syncid = disk->d_sync.ds_syncid;
2249 		}
2250 
2251 		/*
2252 		 * Here we need to look for dirty disks and if all disks
2253 		 * with the biggest syncid are dirty, we have to choose
2254 		 * one with the biggest priority and rebuild the rest.
2255 		 */
2256 		/*
2257 		 * Find the number of dirty disks with the biggest syncid.
2258 		 * Find the number of disks with the biggest syncid.
2259 		 * While here, find a disk with the biggest priority.
2260 		 */
2261 		dirty = ndisks = 0;
2262 		pdisk = NULL;
2263 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2264 			if (disk->d_sync.ds_syncid != syncid)
2265 				continue;
2266 			if ((disk->d_flags &
2267 			    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2268 				continue;
2269 			}
2270 			ndisks++;
2271 			if ((disk->d_flags & G_MIRROR_DISK_FLAG_DIRTY) != 0) {
2272 				dirty++;
2273 				if (pdisk == NULL ||
2274 				    pdisk->d_priority < disk->d_priority) {
2275 					pdisk = disk;
2276 				}
2277 			}
2278 		}
2279 		if (dirty == 0) {
2280 			/* No dirty disks at all, great. */
2281 		} else if (dirty == ndisks) {
2282 			/*
2283 			 * Force synchronization for all dirty disks except one
2284 			 * with the biggest priority.
2285 			 */
2286 			KASSERT(pdisk != NULL, ("pdisk == NULL"));
2287 			G_MIRROR_DEBUG(1, "Using disk %s (device %s) as a "
2288 			    "master disk for synchronization.",
2289 			    g_mirror_get_diskname(pdisk), sc->sc_name);
2290 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2291 				if (disk->d_sync.ds_syncid != syncid)
2292 					continue;
2293 				if ((disk->d_flags &
2294 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2295 					continue;
2296 				}
2297 				KASSERT((disk->d_flags &
2298 				    G_MIRROR_DISK_FLAG_DIRTY) != 0,
2299 				    ("Disk %s isn't marked as dirty.",
2300 				    g_mirror_get_diskname(disk)));
2301 				/* Skip the disk with the biggest priority. */
2302 				if (disk == pdisk)
2303 					continue;
2304 				disk->d_sync.ds_syncid = 0;
2305 			}
2306 		} else if (dirty < ndisks) {
2307 			/*
2308 			 * Force synchronization for all dirty disks.
2309 			 * We have some non-dirty disks.
2310 			 */
2311 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2312 				if (disk->d_sync.ds_syncid != syncid)
2313 					continue;
2314 				if ((disk->d_flags &
2315 				    G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0) {
2316 					continue;
2317 				}
2318 				if ((disk->d_flags &
2319 				    G_MIRROR_DISK_FLAG_DIRTY) == 0) {
2320 					continue;
2321 				}
2322 				disk->d_sync.ds_syncid = 0;
2323 			}
2324 		}
2325 
2326 		/* Reset hint. */
2327 		sc->sc_hint = NULL;
2328 		sc->sc_syncid = syncid;
2329 		if (force) {
2330 			/* Remember to bump syncid on first write. */
2331 			sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2332 		}
2333 		state = G_MIRROR_DEVICE_STATE_RUNNING;
2334 		G_MIRROR_DEBUG(1, "Device %s state changed from %s to %s.",
2335 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state),
2336 		    g_mirror_device_state2str(state));
2337 		sc->sc_state = state;
2338 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2339 			state = g_mirror_determine_state(disk);
2340 			g_mirror_event_send(disk, state,
2341 			    G_MIRROR_EVENT_DONTWAIT);
2342 			if (state == G_MIRROR_DISK_STATE_STALE)
2343 				sc->sc_bump_id |= G_MIRROR_BUMP_SYNCID;
2344 		}
2345 		break;
2346 	    }
2347 	case G_MIRROR_DEVICE_STATE_RUNNING:
2348 		if (g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE) == 0 &&
2349 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2350 			/*
2351 			 * No active disks or no disks at all,
2352 			 * so destroy device.
2353 			 */
2354 			if (sc->sc_provider != NULL)
2355 				g_mirror_destroy_provider(sc);
2356 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2357 			break;
2358 		} else if (g_mirror_ndisks(sc,
2359 		    G_MIRROR_DISK_STATE_ACTIVE) > 0 &&
2360 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_NEW) == 0) {
2361 			/*
2362 			 * We have active disks, launch provider if it doesn't
2363 			 * exist.
2364 			 */
2365 			if (sc->sc_provider == NULL)
2366 				g_mirror_launch_provider(sc);
2367 			if (sc->sc_rootmount != NULL) {
2368 				G_MIRROR_DEBUG(1, "root_mount_rel[%u] %p",
2369 				    __LINE__, sc->sc_rootmount);
2370 				root_mount_rel(sc->sc_rootmount);
2371 				sc->sc_rootmount = NULL;
2372 			}
2373 		}
2374 		/*
2375 		 * Genid should be bumped immediately, so do it here.
2376 		 */
2377 		if ((sc->sc_bump_id & G_MIRROR_BUMP_GENID) != 0) {
2378 			sc->sc_bump_id &= ~G_MIRROR_BUMP_GENID;
2379 			g_mirror_bump_genid(sc);
2380 		}
2381 		break;
2382 	default:
2383 		KASSERT(1 == 0, ("Wrong device state (%s, %s).",
2384 		    sc->sc_name, g_mirror_device_state2str(sc->sc_state)));
2385 		break;
2386 	}
2387 }
2388 
2389 /*
2390  * Update disk state and device state if needed.
2391  */
2392 #define	DISK_STATE_CHANGED()	G_MIRROR_DEBUG(1,			\
2393 	"Disk %s state changed from %s to %s (device %s).",		\
2394 	g_mirror_get_diskname(disk),					\
2395 	g_mirror_disk_state2str(disk->d_state),				\
2396 	g_mirror_disk_state2str(state), sc->sc_name)
2397 static int
2398 g_mirror_update_disk(struct g_mirror_disk *disk, u_int state)
2399 {
2400 	struct g_mirror_softc *sc;
2401 
2402 	sc = disk->d_softc;
2403 	sx_assert(&sc->sc_lock, SX_XLOCKED);
2404 
2405 again:
2406 	G_MIRROR_DEBUG(3, "Changing disk %s state from %s to %s.",
2407 	    g_mirror_get_diskname(disk), g_mirror_disk_state2str(disk->d_state),
2408 	    g_mirror_disk_state2str(state));
2409 	switch (state) {
2410 	case G_MIRROR_DISK_STATE_NEW:
2411 		/*
2412 		 * Possible scenarios:
2413 		 * 1. New disk arrive.
2414 		 */
2415 		/* Previous state should be NONE. */
2416 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NONE,
2417 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2418 		    g_mirror_disk_state2str(disk->d_state)));
2419 		DISK_STATE_CHANGED();
2420 
2421 		disk->d_state = state;
2422 		if (LIST_EMPTY(&sc->sc_disks))
2423 			LIST_INSERT_HEAD(&sc->sc_disks, disk, d_next);
2424 		else {
2425 			struct g_mirror_disk *dp;
2426 
2427 			LIST_FOREACH(dp, &sc->sc_disks, d_next) {
2428 				if (disk->d_priority >= dp->d_priority) {
2429 					LIST_INSERT_BEFORE(dp, disk, d_next);
2430 					dp = NULL;
2431 					break;
2432 				}
2433 				if (LIST_NEXT(dp, d_next) == NULL)
2434 					break;
2435 			}
2436 			if (dp != NULL)
2437 				LIST_INSERT_AFTER(dp, disk, d_next);
2438 		}
2439 		G_MIRROR_DEBUG(1, "Device %s: provider %s detected.",
2440 		    sc->sc_name, g_mirror_get_diskname(disk));
2441 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
2442 			break;
2443 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2444 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2445 		    g_mirror_device_state2str(sc->sc_state),
2446 		    g_mirror_get_diskname(disk),
2447 		    g_mirror_disk_state2str(disk->d_state)));
2448 		state = g_mirror_determine_state(disk);
2449 		if (state != G_MIRROR_DISK_STATE_NONE)
2450 			goto again;
2451 		break;
2452 	case G_MIRROR_DISK_STATE_ACTIVE:
2453 		/*
2454 		 * Possible scenarios:
2455 		 * 1. New disk does not need synchronization.
2456 		 * 2. Synchronization process finished successfully.
2457 		 */
2458 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2459 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2460 		    g_mirror_device_state2str(sc->sc_state),
2461 		    g_mirror_get_diskname(disk),
2462 		    g_mirror_disk_state2str(disk->d_state)));
2463 		/* Previous state should be NEW or SYNCHRONIZING. */
2464 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW ||
2465 		    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2466 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2467 		    g_mirror_disk_state2str(disk->d_state)));
2468 		DISK_STATE_CHANGED();
2469 
2470 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2471 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_SYNCHRONIZING;
2472 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_FORCE_SYNC;
2473 			g_mirror_sync_stop(disk, 0);
2474 		}
2475 		disk->d_state = state;
2476 		disk->d_sync.ds_offset = 0;
2477 		disk->d_sync.ds_offset_done = 0;
2478 		g_mirror_update_idle(sc, disk);
2479 		g_mirror_update_metadata(disk);
2480 		G_MIRROR_DEBUG(1, "Device %s: provider %s activated.",
2481 		    sc->sc_name, g_mirror_get_diskname(disk));
2482 		break;
2483 	case G_MIRROR_DISK_STATE_STALE:
2484 		/*
2485 		 * Possible scenarios:
2486 		 * 1. Stale disk was connected.
2487 		 */
2488 		/* Previous state should be NEW. */
2489 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2490 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2491 		    g_mirror_disk_state2str(disk->d_state)));
2492 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2493 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2494 		    g_mirror_device_state2str(sc->sc_state),
2495 		    g_mirror_get_diskname(disk),
2496 		    g_mirror_disk_state2str(disk->d_state)));
2497 		/*
2498 		 * STALE state is only possible if device is marked
2499 		 * NOAUTOSYNC.
2500 		 */
2501 		KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) != 0,
2502 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2503 		    g_mirror_device_state2str(sc->sc_state),
2504 		    g_mirror_get_diskname(disk),
2505 		    g_mirror_disk_state2str(disk->d_state)));
2506 		DISK_STATE_CHANGED();
2507 
2508 		disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2509 		disk->d_state = state;
2510 		g_mirror_update_metadata(disk);
2511 		G_MIRROR_DEBUG(0, "Device %s: provider %s is stale.",
2512 		    sc->sc_name, g_mirror_get_diskname(disk));
2513 		break;
2514 	case G_MIRROR_DISK_STATE_SYNCHRONIZING:
2515 		/*
2516 		 * Possible scenarios:
2517 		 * 1. Disk which needs synchronization was connected.
2518 		 */
2519 		/* Previous state should be NEW. */
2520 		KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2521 		    ("Wrong disk state (%s, %s).", g_mirror_get_diskname(disk),
2522 		    g_mirror_disk_state2str(disk->d_state)));
2523 		KASSERT(sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING,
2524 		    ("Wrong device state (%s, %s, %s, %s).", sc->sc_name,
2525 		    g_mirror_device_state2str(sc->sc_state),
2526 		    g_mirror_get_diskname(disk),
2527 		    g_mirror_disk_state2str(disk->d_state)));
2528 		DISK_STATE_CHANGED();
2529 
2530 		if (disk->d_state == G_MIRROR_DISK_STATE_NEW)
2531 			disk->d_flags &= ~G_MIRROR_DISK_FLAG_DIRTY;
2532 		disk->d_state = state;
2533 		if (sc->sc_provider != NULL) {
2534 			g_mirror_sync_start(disk);
2535 			g_mirror_update_metadata(disk);
2536 		}
2537 		break;
2538 	case G_MIRROR_DISK_STATE_DISCONNECTED:
2539 		/*
2540 		 * Possible scenarios:
2541 		 * 1. Device wasn't running yet, but disk disappear.
2542 		 * 2. Disk was active and disapppear.
2543 		 * 3. Disk disappear during synchronization process.
2544 		 */
2545 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING) {
2546 			/*
2547 			 * Previous state should be ACTIVE, STALE or
2548 			 * SYNCHRONIZING.
2549 			 */
2550 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_ACTIVE ||
2551 			    disk->d_state == G_MIRROR_DISK_STATE_STALE ||
2552 			    disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING,
2553 			    ("Wrong disk state (%s, %s).",
2554 			    g_mirror_get_diskname(disk),
2555 			    g_mirror_disk_state2str(disk->d_state)));
2556 		} else if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING) {
2557 			/* Previous state should be NEW. */
2558 			KASSERT(disk->d_state == G_MIRROR_DISK_STATE_NEW,
2559 			    ("Wrong disk state (%s, %s).",
2560 			    g_mirror_get_diskname(disk),
2561 			    g_mirror_disk_state2str(disk->d_state)));
2562 			/*
2563 			 * Reset bumping syncid if disk disappeared in STARTING
2564 			 * state.
2565 			 */
2566 			if ((sc->sc_bump_id & G_MIRROR_BUMP_SYNCID) != 0)
2567 				sc->sc_bump_id &= ~G_MIRROR_BUMP_SYNCID;
2568 #ifdef	INVARIANTS
2569 		} else {
2570 			KASSERT(1 == 0, ("Wrong device state (%s, %s, %s, %s).",
2571 			    sc->sc_name,
2572 			    g_mirror_device_state2str(sc->sc_state),
2573 			    g_mirror_get_diskname(disk),
2574 			    g_mirror_disk_state2str(disk->d_state)));
2575 #endif
2576 		}
2577 		DISK_STATE_CHANGED();
2578 		G_MIRROR_DEBUG(0, "Device %s: provider %s disconnected.",
2579 		    sc->sc_name, g_mirror_get_diskname(disk));
2580 
2581 		g_mirror_destroy_disk(disk);
2582 		break;
2583 	case G_MIRROR_DISK_STATE_DESTROY:
2584 	    {
2585 		int error;
2586 
2587 		error = g_mirror_clear_metadata(disk);
2588 		if (error != 0)
2589 			return (error);
2590 		DISK_STATE_CHANGED();
2591 		G_MIRROR_DEBUG(0, "Device %s: provider %s destroyed.",
2592 		    sc->sc_name, g_mirror_get_diskname(disk));
2593 
2594 		g_mirror_destroy_disk(disk);
2595 		sc->sc_ndisks--;
2596 		LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2597 			g_mirror_update_metadata(disk);
2598 		}
2599 		break;
2600 	    }
2601 	default:
2602 		KASSERT(1 == 0, ("Unknown state (%u).", state));
2603 		break;
2604 	}
2605 	return (0);
2606 }
2607 #undef	DISK_STATE_CHANGED
2608 
2609 int
2610 g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md)
2611 {
2612 	struct g_provider *pp;
2613 	u_char *buf;
2614 	int error;
2615 
2616 	g_topology_assert();
2617 
2618 	error = g_access(cp, 1, 0, 0);
2619 	if (error != 0)
2620 		return (error);
2621 	pp = cp->provider;
2622 	g_topology_unlock();
2623 	/* Metadata are stored on last sector. */
2624 	buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
2625 	    &error);
2626 	g_topology_lock();
2627 	g_access(cp, -1, 0, 0);
2628 	if (buf == NULL) {
2629 		G_MIRROR_DEBUG(1, "Cannot read metadata from %s (error=%d).",
2630 		    cp->provider->name, error);
2631 		return (error);
2632 	}
2633 
2634 	/* Decode metadata. */
2635 	error = mirror_metadata_decode(buf, md);
2636 	g_free(buf);
2637 	if (strcmp(md->md_magic, G_MIRROR_MAGIC) != 0)
2638 		return (EINVAL);
2639 	if (md->md_version > G_MIRROR_VERSION) {
2640 		G_MIRROR_DEBUG(0,
2641 		    "Kernel module is too old to handle metadata from %s.",
2642 		    cp->provider->name);
2643 		return (EINVAL);
2644 	}
2645 	if (error != 0) {
2646 		G_MIRROR_DEBUG(1, "MD5 metadata hash mismatch for provider %s.",
2647 		    cp->provider->name);
2648 		return (error);
2649 	}
2650 
2651 	return (0);
2652 }
2653 
2654 static int
2655 g_mirror_check_metadata(struct g_mirror_softc *sc, struct g_provider *pp,
2656     struct g_mirror_metadata *md)
2657 {
2658 
2659 	if (g_mirror_id2disk(sc, md->md_did) != NULL) {
2660 		G_MIRROR_DEBUG(1, "Disk %s (id=%u) already exists, skipping.",
2661 		    pp->name, md->md_did);
2662 		return (EEXIST);
2663 	}
2664 	if (md->md_all != sc->sc_ndisks) {
2665 		G_MIRROR_DEBUG(1,
2666 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2667 		    "md_all", pp->name, sc->sc_name);
2668 		return (EINVAL);
2669 	}
2670 	if (md->md_slice != sc->sc_slice) {
2671 		G_MIRROR_DEBUG(1,
2672 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2673 		    "md_slice", pp->name, sc->sc_name);
2674 		return (EINVAL);
2675 	}
2676 	if (md->md_balance != sc->sc_balance) {
2677 		G_MIRROR_DEBUG(1,
2678 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2679 		    "md_balance", pp->name, sc->sc_name);
2680 		return (EINVAL);
2681 	}
2682 	if (md->md_mediasize != sc->sc_mediasize) {
2683 		G_MIRROR_DEBUG(1,
2684 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2685 		    "md_mediasize", pp->name, sc->sc_name);
2686 		return (EINVAL);
2687 	}
2688 	if (sc->sc_mediasize > pp->mediasize) {
2689 		G_MIRROR_DEBUG(1,
2690 		    "Invalid size of disk %s (device %s), skipping.", pp->name,
2691 		    sc->sc_name);
2692 		return (EINVAL);
2693 	}
2694 	if (md->md_sectorsize != sc->sc_sectorsize) {
2695 		G_MIRROR_DEBUG(1,
2696 		    "Invalid '%s' field on disk %s (device %s), skipping.",
2697 		    "md_sectorsize", pp->name, sc->sc_name);
2698 		return (EINVAL);
2699 	}
2700 	if ((sc->sc_sectorsize % pp->sectorsize) != 0) {
2701 		G_MIRROR_DEBUG(1,
2702 		    "Invalid sector size of disk %s (device %s), skipping.",
2703 		    pp->name, sc->sc_name);
2704 		return (EINVAL);
2705 	}
2706 	if ((md->md_mflags & ~G_MIRROR_DEVICE_FLAG_MASK) != 0) {
2707 		G_MIRROR_DEBUG(1,
2708 		    "Invalid device flags on disk %s (device %s), skipping.",
2709 		    pp->name, sc->sc_name);
2710 		return (EINVAL);
2711 	}
2712 	if ((md->md_dflags & ~G_MIRROR_DISK_FLAG_MASK) != 0) {
2713 		G_MIRROR_DEBUG(1,
2714 		    "Invalid disk flags on disk %s (device %s), skipping.",
2715 		    pp->name, sc->sc_name);
2716 		return (EINVAL);
2717 	}
2718 	return (0);
2719 }
2720 
2721 int
2722 g_mirror_add_disk(struct g_mirror_softc *sc, struct g_provider *pp,
2723     struct g_mirror_metadata *md)
2724 {
2725 	struct g_mirror_disk *disk;
2726 	int error;
2727 
2728 	g_topology_assert_not();
2729 	G_MIRROR_DEBUG(2, "Adding disk %s.", pp->name);
2730 
2731 	error = g_mirror_check_metadata(sc, pp, md);
2732 	if (error != 0)
2733 		return (error);
2734 	if (sc->sc_state == G_MIRROR_DEVICE_STATE_RUNNING &&
2735 	    md->md_genid < sc->sc_genid) {
2736 		G_MIRROR_DEBUG(0, "Component %s (device %s) broken, skipping.",
2737 		    pp->name, sc->sc_name);
2738 		return (EINVAL);
2739 	}
2740 	disk = g_mirror_init_disk(sc, pp, md, &error);
2741 	if (disk == NULL)
2742 		return (error);
2743 	error = g_mirror_event_send(disk, G_MIRROR_DISK_STATE_NEW,
2744 	    G_MIRROR_EVENT_WAIT);
2745 	if (error != 0)
2746 		return (error);
2747 	if (md->md_version < G_MIRROR_VERSION) {
2748 		G_MIRROR_DEBUG(0, "Upgrading metadata on %s (v%d->v%d).",
2749 		    pp->name, md->md_version, G_MIRROR_VERSION);
2750 		g_mirror_update_metadata(disk);
2751 	}
2752 	return (0);
2753 }
2754 
2755 static void
2756 g_mirror_destroy_delayed(void *arg, int flag)
2757 {
2758 	struct g_mirror_softc *sc;
2759 	int error;
2760 
2761 	if (flag == EV_CANCEL) {
2762 		G_MIRROR_DEBUG(1, "Destroying canceled.");
2763 		return;
2764 	}
2765 	sc = arg;
2766 	g_topology_unlock();
2767 	sx_xlock(&sc->sc_lock);
2768 	KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) == 0,
2769 	    ("DESTROY flag set on %s.", sc->sc_name));
2770 	KASSERT((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROYING) != 0,
2771 	    ("DESTROYING flag not set on %s.", sc->sc_name));
2772 	G_MIRROR_DEBUG(1, "Destroying %s (delayed).", sc->sc_name);
2773 	error = g_mirror_destroy(sc, G_MIRROR_DESTROY_SOFT);
2774 	if (error != 0) {
2775 		G_MIRROR_DEBUG(0, "Cannot destroy %s.", sc->sc_name);
2776 		sx_xunlock(&sc->sc_lock);
2777 	}
2778 	g_topology_lock();
2779 }
2780 
2781 static int
2782 g_mirror_access(struct g_provider *pp, int acr, int acw, int ace)
2783 {
2784 	struct g_mirror_softc *sc;
2785 	int dcr, dcw, dce, error = 0;
2786 
2787 	g_topology_assert();
2788 	G_MIRROR_DEBUG(2, "Access request for %s: r%dw%de%d.", pp->name, acr,
2789 	    acw, ace);
2790 
2791 	sc = pp->geom->softc;
2792 	if (sc == NULL && acr <= 0 && acw <= 0 && ace <= 0)
2793 		return (0);
2794 	KASSERT(sc != NULL, ("NULL softc (provider=%s).", pp->name));
2795 
2796 	dcr = pp->acr + acr;
2797 	dcw = pp->acw + acw;
2798 	dce = pp->ace + ace;
2799 
2800 	g_topology_unlock();
2801 	sx_xlock(&sc->sc_lock);
2802 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROY) != 0 ||
2803 	    LIST_EMPTY(&sc->sc_disks)) {
2804 		if (acr > 0 || acw > 0 || ace > 0)
2805 			error = ENXIO;
2806 		goto end;
2807 	}
2808 	if (dcw == 0 && !sc->sc_idle)
2809 		g_mirror_idle(sc, dcw);
2810 	if ((sc->sc_flags & G_MIRROR_DEVICE_FLAG_DESTROYING) != 0) {
2811 		if (acr > 0 || acw > 0 || ace > 0) {
2812 			error = ENXIO;
2813 			goto end;
2814 		}
2815 		if (dcr == 0 && dcw == 0 && dce == 0) {
2816 			g_post_event(g_mirror_destroy_delayed, sc, M_WAITOK,
2817 			    sc, NULL);
2818 		}
2819 	}
2820 end:
2821 	sx_xunlock(&sc->sc_lock);
2822 	g_topology_lock();
2823 	return (error);
2824 }
2825 
2826 static struct g_geom *
2827 g_mirror_create(struct g_class *mp, const struct g_mirror_metadata *md)
2828 {
2829 	struct g_mirror_softc *sc;
2830 	struct g_geom *gp;
2831 	int error, timeout;
2832 
2833 	g_topology_assert();
2834 	G_MIRROR_DEBUG(1, "Creating device %s (id=%u).", md->md_name,
2835 	    md->md_mid);
2836 
2837 	/* One disk is minimum. */
2838 	if (md->md_all < 1)
2839 		return (NULL);
2840 	/*
2841 	 * Action geom.
2842 	 */
2843 	gp = g_new_geomf(mp, "%s", md->md_name);
2844 	sc = malloc(sizeof(*sc), M_MIRROR, M_WAITOK | M_ZERO);
2845 	gp->start = g_mirror_start;
2846 	gp->orphan = g_mirror_orphan;
2847 	gp->access = g_mirror_access;
2848 	gp->dumpconf = g_mirror_dumpconf;
2849 
2850 	sc->sc_id = md->md_mid;
2851 	sc->sc_slice = md->md_slice;
2852 	sc->sc_balance = md->md_balance;
2853 	sc->sc_mediasize = md->md_mediasize;
2854 	sc->sc_sectorsize = md->md_sectorsize;
2855 	sc->sc_ndisks = md->md_all;
2856 	sc->sc_flags = md->md_mflags;
2857 	sc->sc_bump_id = 0;
2858 	sc->sc_idle = 1;
2859 	sc->sc_last_write = time_uptime;
2860 	sc->sc_writes = 0;
2861 	sx_init(&sc->sc_lock, "gmirror:lock");
2862 	bioq_init(&sc->sc_queue);
2863 	mtx_init(&sc->sc_queue_mtx, "gmirror:queue", NULL, MTX_DEF);
2864 	bioq_init(&sc->sc_regular_delayed);
2865 	bioq_init(&sc->sc_inflight);
2866 	bioq_init(&sc->sc_sync_delayed);
2867 	LIST_INIT(&sc->sc_disks);
2868 	TAILQ_INIT(&sc->sc_events);
2869 	mtx_init(&sc->sc_events_mtx, "gmirror:events", NULL, MTX_DEF);
2870 	callout_init(&sc->sc_callout, CALLOUT_MPSAFE);
2871 	sc->sc_state = G_MIRROR_DEVICE_STATE_STARTING;
2872 	gp->softc = sc;
2873 	sc->sc_geom = gp;
2874 	sc->sc_provider = NULL;
2875 	/*
2876 	 * Synchronization geom.
2877 	 */
2878 	gp = g_new_geomf(mp, "%s.sync", md->md_name);
2879 	gp->softc = sc;
2880 	gp->orphan = g_mirror_orphan;
2881 	sc->sc_sync.ds_geom = gp;
2882 	sc->sc_sync.ds_ndisks = 0;
2883 	error = kproc_create(g_mirror_worker, sc, &sc->sc_worker, 0, 0,
2884 	    "g_mirror %s", md->md_name);
2885 	if (error != 0) {
2886 		G_MIRROR_DEBUG(1, "Cannot create kernel thread for %s.",
2887 		    sc->sc_name);
2888 		g_destroy_geom(sc->sc_sync.ds_geom);
2889 		mtx_destroy(&sc->sc_events_mtx);
2890 		mtx_destroy(&sc->sc_queue_mtx);
2891 		sx_destroy(&sc->sc_lock);
2892 		g_destroy_geom(sc->sc_geom);
2893 		free(sc, M_MIRROR);
2894 		return (NULL);
2895 	}
2896 
2897 	G_MIRROR_DEBUG(1, "Device %s created (%u components, id=%u).",
2898 	    sc->sc_name, sc->sc_ndisks, sc->sc_id);
2899 
2900 	sc->sc_rootmount = root_mount_hold("GMIRROR");
2901 	G_MIRROR_DEBUG(1, "root_mount_hold %p", sc->sc_rootmount);
2902 	/*
2903 	 * Run timeout.
2904 	 */
2905 	timeout = g_mirror_timeout * hz;
2906 	callout_reset(&sc->sc_callout, timeout, g_mirror_go, sc);
2907 	return (sc->sc_geom);
2908 }
2909 
2910 int
2911 g_mirror_destroy(struct g_mirror_softc *sc, int how)
2912 {
2913 	struct g_mirror_disk *disk;
2914 	struct g_provider *pp;
2915 
2916 	g_topology_assert_not();
2917 	if (sc == NULL)
2918 		return (ENXIO);
2919 	sx_assert(&sc->sc_lock, SX_XLOCKED);
2920 
2921 	pp = sc->sc_provider;
2922 	if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
2923 		switch (how) {
2924 		case G_MIRROR_DESTROY_SOFT:
2925 			G_MIRROR_DEBUG(1,
2926 			    "Device %s is still open (r%dw%de%d).", pp->name,
2927 			    pp->acr, pp->acw, pp->ace);
2928 			return (EBUSY);
2929 		case G_MIRROR_DESTROY_DELAYED:
2930 			G_MIRROR_DEBUG(1,
2931 			    "Device %s will be destroyed on last close.",
2932 			    pp->name);
2933 			LIST_FOREACH(disk, &sc->sc_disks, d_next) {
2934 				if (disk->d_state ==
2935 				    G_MIRROR_DISK_STATE_SYNCHRONIZING) {
2936 					g_mirror_sync_stop(disk, 1);
2937 				}
2938 			}
2939 			sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROYING;
2940 			return (EBUSY);
2941 		case G_MIRROR_DESTROY_HARD:
2942 			G_MIRROR_DEBUG(1, "Device %s is still open, so it "
2943 			    "can't be definitely removed.", pp->name);
2944 		}
2945 	}
2946 
2947 	g_topology_lock();
2948 	if (sc->sc_geom->softc == NULL) {
2949 		g_topology_unlock();
2950 		return (0);
2951 	}
2952 	sc->sc_geom->softc = NULL;
2953 	sc->sc_sync.ds_geom->softc = NULL;
2954 	g_topology_unlock();
2955 
2956 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_DESTROY;
2957 	sc->sc_flags |= G_MIRROR_DEVICE_FLAG_WAIT;
2958 	G_MIRROR_DEBUG(4, "%s: Waking up %p.", __func__, sc);
2959 	sx_xunlock(&sc->sc_lock);
2960 	mtx_lock(&sc->sc_queue_mtx);
2961 	wakeup(sc);
2962 	mtx_unlock(&sc->sc_queue_mtx);
2963 	G_MIRROR_DEBUG(4, "%s: Sleeping %p.", __func__, &sc->sc_worker);
2964 	while (sc->sc_worker != NULL)
2965 		tsleep(&sc->sc_worker, PRIBIO, "m:destroy", hz / 5);
2966 	G_MIRROR_DEBUG(4, "%s: Woken up %p.", __func__, &sc->sc_worker);
2967 	sx_xlock(&sc->sc_lock);
2968 	g_mirror_destroy_device(sc);
2969 	free(sc, M_MIRROR);
2970 	return (0);
2971 }
2972 
2973 static void
2974 g_mirror_taste_orphan(struct g_consumer *cp)
2975 {
2976 
2977 	KASSERT(1 == 0, ("%s called while tasting %s.", __func__,
2978 	    cp->provider->name));
2979 }
2980 
2981 static struct g_geom *
2982 g_mirror_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
2983 {
2984 	struct g_mirror_metadata md;
2985 	struct g_mirror_softc *sc;
2986 	struct g_consumer *cp;
2987 	struct g_geom *gp;
2988 	int error;
2989 
2990 	g_topology_assert();
2991 	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
2992 	G_MIRROR_DEBUG(2, "Tasting %s.", pp->name);
2993 
2994 	gp = g_new_geomf(mp, "mirror:taste");
2995 	/*
2996 	 * This orphan function should be never called.
2997 	 */
2998 	gp->orphan = g_mirror_taste_orphan;
2999 	cp = g_new_consumer(gp);
3000 	g_attach(cp, pp);
3001 	error = g_mirror_read_metadata(cp, &md);
3002 	g_detach(cp);
3003 	g_destroy_consumer(cp);
3004 	g_destroy_geom(gp);
3005 	if (error != 0)
3006 		return (NULL);
3007 	gp = NULL;
3008 
3009 	if (md.md_provider[0] != '\0' && strcmp(md.md_provider, pp->name) != 0)
3010 		return (NULL);
3011 	if (md.md_provsize != 0 && md.md_provsize != pp->mediasize)
3012 		return (NULL);
3013 	if ((md.md_dflags & G_MIRROR_DISK_FLAG_INACTIVE) != 0) {
3014 		G_MIRROR_DEBUG(0,
3015 		    "Device %s: provider %s marked as inactive, skipping.",
3016 		    md.md_name, pp->name);
3017 		return (NULL);
3018 	}
3019 	if (g_mirror_debug >= 2)
3020 		mirror_metadata_dump(&md);
3021 
3022 	/*
3023 	 * Let's check if device already exists.
3024 	 */
3025 	sc = NULL;
3026 	LIST_FOREACH(gp, &mp->geom, geom) {
3027 		sc = gp->softc;
3028 		if (sc == NULL)
3029 			continue;
3030 		if (sc->sc_sync.ds_geom == gp)
3031 			continue;
3032 		if (strcmp(md.md_name, sc->sc_name) != 0)
3033 			continue;
3034 		if (md.md_mid != sc->sc_id) {
3035 			G_MIRROR_DEBUG(0, "Device %s already configured.",
3036 			    sc->sc_name);
3037 			return (NULL);
3038 		}
3039 		break;
3040 	}
3041 	if (gp == NULL) {
3042 		gp = g_mirror_create(mp, &md);
3043 		if (gp == NULL) {
3044 			G_MIRROR_DEBUG(0, "Cannot create device %s.",
3045 			    md.md_name);
3046 			return (NULL);
3047 		}
3048 		sc = gp->softc;
3049 	}
3050 	G_MIRROR_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
3051 	g_topology_unlock();
3052 	sx_xlock(&sc->sc_lock);
3053 	error = g_mirror_add_disk(sc, pp, &md);
3054 	if (error != 0) {
3055 		G_MIRROR_DEBUG(0, "Cannot add disk %s to %s (error=%d).",
3056 		    pp->name, gp->name, error);
3057 		if (LIST_EMPTY(&sc->sc_disks)) {
3058 			g_cancel_event(sc);
3059 			g_mirror_destroy(sc, G_MIRROR_DESTROY_HARD);
3060 			g_topology_lock();
3061 			return (NULL);
3062 		}
3063 		gp = NULL;
3064 	}
3065 	sx_xunlock(&sc->sc_lock);
3066 	g_topology_lock();
3067 	return (gp);
3068 }
3069 
3070 static int
3071 g_mirror_destroy_geom(struct gctl_req *req __unused,
3072     struct g_class *mp __unused, struct g_geom *gp)
3073 {
3074 	struct g_mirror_softc *sc;
3075 	int error;
3076 
3077 	g_topology_unlock();
3078 	sc = gp->softc;
3079 	sx_xlock(&sc->sc_lock);
3080 	g_cancel_event(sc);
3081 	error = g_mirror_destroy(gp->softc, G_MIRROR_DESTROY_SOFT);
3082 	if (error != 0)
3083 		sx_xunlock(&sc->sc_lock);
3084 	g_topology_lock();
3085 	return (error);
3086 }
3087 
3088 static void
3089 g_mirror_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
3090     struct g_consumer *cp, struct g_provider *pp)
3091 {
3092 	struct g_mirror_softc *sc;
3093 
3094 	g_topology_assert();
3095 
3096 	sc = gp->softc;
3097 	if (sc == NULL)
3098 		return;
3099 	/* Skip synchronization geom. */
3100 	if (gp == sc->sc_sync.ds_geom)
3101 		return;
3102 	if (pp != NULL) {
3103 		/* Nothing here. */
3104 	} else if (cp != NULL) {
3105 		struct g_mirror_disk *disk;
3106 
3107 		disk = cp->private;
3108 		if (disk == NULL)
3109 			return;
3110 		g_topology_unlock();
3111 		sx_xlock(&sc->sc_lock);
3112 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)disk->d_id);
3113 		if (disk->d_state == G_MIRROR_DISK_STATE_SYNCHRONIZING) {
3114 			sbuf_printf(sb, "%s<Synchronized>", indent);
3115 			if (disk->d_sync.ds_offset == 0)
3116 				sbuf_printf(sb, "0%%");
3117 			else {
3118 				sbuf_printf(sb, "%u%%",
3119 				    (u_int)((disk->d_sync.ds_offset * 100) /
3120 				    sc->sc_provider->mediasize));
3121 			}
3122 			sbuf_printf(sb, "</Synchronized>\n");
3123 		}
3124 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent,
3125 		    disk->d_sync.ds_syncid);
3126 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent,
3127 		    disk->d_genid);
3128 		sbuf_printf(sb, "%s<Flags>", indent);
3129 		if (disk->d_flags == 0)
3130 			sbuf_printf(sb, "NONE");
3131 		else {
3132 			int first = 1;
3133 
3134 #define	ADD_FLAG(flag, name)	do {					\
3135 	if ((disk->d_flags & (flag)) != 0) {				\
3136 		if (!first)						\
3137 			sbuf_printf(sb, ", ");				\
3138 		else							\
3139 			first = 0;					\
3140 		sbuf_printf(sb, name);					\
3141 	}								\
3142 } while (0)
3143 			ADD_FLAG(G_MIRROR_DISK_FLAG_DIRTY, "DIRTY");
3144 			ADD_FLAG(G_MIRROR_DISK_FLAG_HARDCODED, "HARDCODED");
3145 			ADD_FLAG(G_MIRROR_DISK_FLAG_INACTIVE, "INACTIVE");
3146 			ADD_FLAG(G_MIRROR_DISK_FLAG_SYNCHRONIZING,
3147 			    "SYNCHRONIZING");
3148 			ADD_FLAG(G_MIRROR_DISK_FLAG_FORCE_SYNC, "FORCE_SYNC");
3149 			ADD_FLAG(G_MIRROR_DISK_FLAG_BROKEN, "BROKEN");
3150 #undef	ADD_FLAG
3151 		}
3152 		sbuf_printf(sb, "</Flags>\n");
3153 		sbuf_printf(sb, "%s<Priority>%u</Priority>\n", indent,
3154 		    disk->d_priority);
3155 		sbuf_printf(sb, "%s<State>%s</State>\n", indent,
3156 		    g_mirror_disk_state2str(disk->d_state));
3157 		sx_xunlock(&sc->sc_lock);
3158 		g_topology_lock();
3159 	} else {
3160 		g_topology_unlock();
3161 		sx_xlock(&sc->sc_lock);
3162 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)sc->sc_id);
3163 		sbuf_printf(sb, "%s<SyncID>%u</SyncID>\n", indent, sc->sc_syncid);
3164 		sbuf_printf(sb, "%s<GenID>%u</GenID>\n", indent, sc->sc_genid);
3165 		sbuf_printf(sb, "%s<Flags>", indent);
3166 		if (sc->sc_flags == 0)
3167 			sbuf_printf(sb, "NONE");
3168 		else {
3169 			int first = 1;
3170 
3171 #define	ADD_FLAG(flag, name)	do {					\
3172 	if ((sc->sc_flags & (flag)) != 0) {				\
3173 		if (!first)						\
3174 			sbuf_printf(sb, ", ");				\
3175 		else							\
3176 			first = 0;					\
3177 		sbuf_printf(sb, name);					\
3178 	}								\
3179 } while (0)
3180 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOFAILSYNC, "NOFAILSYNC");
3181 			ADD_FLAG(G_MIRROR_DEVICE_FLAG_NOAUTOSYNC, "NOAUTOSYNC");
3182 #undef	ADD_FLAG
3183 		}
3184 		sbuf_printf(sb, "</Flags>\n");
3185 		sbuf_printf(sb, "%s<Slice>%u</Slice>\n", indent,
3186 		    (u_int)sc->sc_slice);
3187 		sbuf_printf(sb, "%s<Balance>%s</Balance>\n", indent,
3188 		    balance_name(sc->sc_balance));
3189 		sbuf_printf(sb, "%s<Components>%u</Components>\n", indent,
3190 		    sc->sc_ndisks);
3191 		sbuf_printf(sb, "%s<State>", indent);
3192 		if (sc->sc_state == G_MIRROR_DEVICE_STATE_STARTING)
3193 			sbuf_printf(sb, "%s", "STARTING");
3194 		else if (sc->sc_ndisks ==
3195 		    g_mirror_ndisks(sc, G_MIRROR_DISK_STATE_ACTIVE))
3196 			sbuf_printf(sb, "%s", "COMPLETE");
3197 		else
3198 			sbuf_printf(sb, "%s", "DEGRADED");
3199 		sbuf_printf(sb, "</State>\n");
3200 		sx_xunlock(&sc->sc_lock);
3201 		g_topology_lock();
3202 	}
3203 }
3204 
3205 static void
3206 g_mirror_shutdown_pre_sync(void *arg, int howto)
3207 {
3208 	struct g_class *mp;
3209 	struct g_geom *gp, *gp2;
3210 	struct g_mirror_softc *sc;
3211 	int error;
3212 
3213 	mp = arg;
3214 	DROP_GIANT();
3215 	g_topology_lock();
3216 	LIST_FOREACH_SAFE(gp, &mp->geom, geom, gp2) {
3217 		if ((sc = gp->softc) == NULL)
3218 			continue;
3219 		/* Skip synchronization geom. */
3220 		if (gp == sc->sc_sync.ds_geom)
3221 			continue;
3222 		g_topology_unlock();
3223 		sx_xlock(&sc->sc_lock);
3224 		g_cancel_event(sc);
3225 		error = g_mirror_destroy(sc, G_MIRROR_DESTROY_DELAYED);
3226 		if (error != 0)
3227 			sx_xunlock(&sc->sc_lock);
3228 		g_topology_lock();
3229 	}
3230 	g_topology_unlock();
3231 	PICKUP_GIANT();
3232 }
3233 
3234 static void
3235 g_mirror_init(struct g_class *mp)
3236 {
3237 
3238 	g_mirror_pre_sync = EVENTHANDLER_REGISTER(shutdown_pre_sync,
3239 	    g_mirror_shutdown_pre_sync, mp, SHUTDOWN_PRI_FIRST);
3240 	if (g_mirror_pre_sync == NULL)
3241 		G_MIRROR_DEBUG(0, "Warning! Cannot register shutdown event.");
3242 }
3243 
3244 static void
3245 g_mirror_fini(struct g_class *mp)
3246 {
3247 
3248 	if (g_mirror_pre_sync != NULL)
3249 		EVENTHANDLER_DEREGISTER(shutdown_pre_sync, g_mirror_pre_sync);
3250 }
3251 
3252 DECLARE_GEOM_CLASS(g_mirror_class, g_mirror);
3253