xref: /freebsd/sys/geom/stripe/g_stripe.c (revision eb6d21b4ca6d668cf89afd99eef7baeafa712197)
1 /*-
2  * Copyright (c) 2004-2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
33 #include <sys/module.h>
34 #include <sys/lock.h>
35 #include <sys/mutex.h>
36 #include <sys/bio.h>
37 #include <sys/sysctl.h>
38 #include <sys/malloc.h>
39 #include <vm/uma.h>
40 #include <geom/geom.h>
41 #include <geom/stripe/g_stripe.h>
42 
43 
44 static MALLOC_DEFINE(M_STRIPE, "stripe_data", "GEOM_STRIPE Data");
45 
46 static uma_zone_t g_stripe_zone;
47 
48 static int g_stripe_destroy(struct g_stripe_softc *sc, boolean_t force);
49 static int g_stripe_destroy_geom(struct gctl_req *req, struct g_class *mp,
50     struct g_geom *gp);
51 
52 static g_taste_t g_stripe_taste;
53 static g_ctl_req_t g_stripe_config;
54 static g_dumpconf_t g_stripe_dumpconf;
55 static g_init_t g_stripe_init;
56 static g_fini_t g_stripe_fini;
57 
58 struct g_class g_stripe_class = {
59 	.name = G_STRIPE_CLASS_NAME,
60 	.version = G_VERSION,
61 	.ctlreq = g_stripe_config,
62 	.taste = g_stripe_taste,
63 	.destroy_geom = g_stripe_destroy_geom,
64 	.init = g_stripe_init,
65 	.fini = g_stripe_fini
66 };
67 
68 SYSCTL_DECL(_kern_geom);
69 SYSCTL_NODE(_kern_geom, OID_AUTO, stripe, CTLFLAG_RW, 0, "GEOM_STRIPE stuff");
70 static u_int g_stripe_debug = 0;
71 TUNABLE_INT("kern.geom.stripe.debug", &g_stripe_debug);
72 SYSCTL_UINT(_kern_geom_stripe, OID_AUTO, debug, CTLFLAG_RW, &g_stripe_debug, 0,
73     "Debug level");
74 static int g_stripe_fast = 0;
75 TUNABLE_INT("kern.geom.stripe.fast", &g_stripe_fast);
76 static int
77 g_sysctl_stripe_fast(SYSCTL_HANDLER_ARGS)
78 {
79 	int error, fast;
80 
81 	fast = g_stripe_fast;
82 	error = sysctl_handle_int(oidp, &fast, 0, req);
83 	if (error == 0 && req->newptr != NULL)
84 		g_stripe_fast = fast;
85 	return (error);
86 }
87 SYSCTL_PROC(_kern_geom_stripe, OID_AUTO, fast, CTLTYPE_INT | CTLFLAG_RW,
88     NULL, 0, g_sysctl_stripe_fast, "I", "Fast, but memory-consuming, mode");
89 static u_int g_stripe_maxmem = MAXPHYS * 100;
90 TUNABLE_INT("kern.geom.stripe.maxmem", &g_stripe_maxmem);
91 SYSCTL_UINT(_kern_geom_stripe, OID_AUTO, maxmem, CTLFLAG_RD, &g_stripe_maxmem,
92     0, "Maximum memory that can be allocated in \"fast\" mode (in bytes)");
93 static u_int g_stripe_fast_failed = 0;
94 SYSCTL_UINT(_kern_geom_stripe, OID_AUTO, fast_failed, CTLFLAG_RD,
95     &g_stripe_fast_failed, 0, "How many times \"fast\" mode failed");
96 
97 /*
98  * Greatest Common Divisor.
99  */
100 static u_int
101 gcd(u_int a, u_int b)
102 {
103 	u_int c;
104 
105 	while (b != 0) {
106 		c = a;
107 		a = b;
108 		b = (c % b);
109 	}
110 	return (a);
111 }
112 
113 /*
114  * Least Common Multiple.
115  */
116 static u_int
117 lcm(u_int a, u_int b)
118 {
119 
120 	return ((a * b) / gcd(a, b));
121 }
122 
123 static void
124 g_stripe_init(struct g_class *mp __unused)
125 {
126 
127 	g_stripe_zone = uma_zcreate("g_stripe_zone", MAXPHYS, NULL, NULL,
128 	    NULL, NULL, 0, 0);
129 	g_stripe_maxmem -= g_stripe_maxmem % MAXPHYS;
130 	uma_zone_set_max(g_stripe_zone, g_stripe_maxmem / MAXPHYS);
131 }
132 
133 static void
134 g_stripe_fini(struct g_class *mp __unused)
135 {
136 
137 	uma_zdestroy(g_stripe_zone);
138 }
139 
140 /*
141  * Return the number of valid disks.
142  */
143 static u_int
144 g_stripe_nvalid(struct g_stripe_softc *sc)
145 {
146 	u_int i, no;
147 
148 	no = 0;
149 	for (i = 0; i < sc->sc_ndisks; i++) {
150 		if (sc->sc_disks[i] != NULL)
151 			no++;
152 	}
153 
154 	return (no);
155 }
156 
157 static void
158 g_stripe_remove_disk(struct g_consumer *cp)
159 {
160 	struct g_stripe_softc *sc;
161 	u_int no;
162 
163 	KASSERT(cp != NULL, ("Non-valid disk in %s.", __func__));
164 	sc = (struct g_stripe_softc *)cp->private;
165 	KASSERT(sc != NULL, ("NULL sc in %s.", __func__));
166 	no = cp->index;
167 
168 	G_STRIPE_DEBUG(0, "Disk %s removed from %s.", cp->provider->name,
169 	    sc->sc_name);
170 
171 	sc->sc_disks[no] = NULL;
172 	if (sc->sc_provider != NULL) {
173 		sc->sc_provider->flags |= G_PF_WITHER;
174 		g_orphan_provider(sc->sc_provider, ENXIO);
175 		sc->sc_provider = NULL;
176 		G_STRIPE_DEBUG(0, "Device %s removed.", sc->sc_name);
177 	}
178 
179 	if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
180 		g_access(cp, -cp->acr, -cp->acw, -cp->ace);
181 	g_detach(cp);
182 	g_destroy_consumer(cp);
183 }
184 
185 static void
186 g_stripe_orphan(struct g_consumer *cp)
187 {
188 	struct g_stripe_softc *sc;
189 	struct g_geom *gp;
190 
191 	g_topology_assert();
192 	gp = cp->geom;
193 	sc = gp->softc;
194 	if (sc == NULL)
195 		return;
196 
197 	g_stripe_remove_disk(cp);
198 	/* If there are no valid disks anymore, remove device. */
199 	if (g_stripe_nvalid(sc) == 0)
200 		g_stripe_destroy(sc, 1);
201 }
202 
203 static int
204 g_stripe_access(struct g_provider *pp, int dr, int dw, int de)
205 {
206 	struct g_consumer *cp1, *cp2;
207 	struct g_stripe_softc *sc;
208 	struct g_geom *gp;
209 	int error;
210 
211 	gp = pp->geom;
212 	sc = gp->softc;
213 
214 	if (sc == NULL) {
215 		/*
216 		 * It looks like geom is being withered.
217 		 * In that case we allow only negative requests.
218 		 */
219 		KASSERT(dr <= 0 && dw <= 0 && de <= 0,
220 		    ("Positive access request (device=%s).", pp->name));
221 		if ((pp->acr + dr) == 0 && (pp->acw + dw) == 0 &&
222 		    (pp->ace + de) == 0) {
223 			G_STRIPE_DEBUG(0, "Device %s definitely destroyed.",
224 			    gp->name);
225 		}
226 		return (0);
227 	}
228 
229 	/* On first open, grab an extra "exclusive" bit */
230 	if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0)
231 		de++;
232 	/* ... and let go of it on last close */
233 	if ((pp->acr + dr) == 0 && (pp->acw + dw) == 0 && (pp->ace + de) == 0)
234 		de--;
235 
236 	error = ENXIO;
237 	LIST_FOREACH(cp1, &gp->consumer, consumer) {
238 		error = g_access(cp1, dr, dw, de);
239 		if (error == 0)
240 			continue;
241 		/*
242 		 * If we fail here, backout all previous changes.
243 		 */
244 		LIST_FOREACH(cp2, &gp->consumer, consumer) {
245 			if (cp1 == cp2)
246 				return (error);
247 			g_access(cp2, -dr, -dw, -de);
248 		}
249 		/* NOTREACHED */
250 	}
251 
252 	return (error);
253 }
254 
255 static void
256 g_stripe_copy(struct g_stripe_softc *sc, char *src, char *dst, off_t offset,
257     off_t length, int mode)
258 {
259 	u_int stripesize;
260 	size_t len;
261 
262 	stripesize = sc->sc_stripesize;
263 	len = (size_t)(stripesize - (offset & (stripesize - 1)));
264 	do {
265 		bcopy(src, dst, len);
266 		if (mode) {
267 			dst += len + stripesize * (sc->sc_ndisks - 1);
268 			src += len;
269 		} else {
270 			dst += len;
271 			src += len + stripesize * (sc->sc_ndisks - 1);
272 		}
273 		length -= len;
274 		KASSERT(length >= 0,
275 		    ("Length < 0 (stripesize=%zu, offset=%jd, length=%jd).",
276 		    (size_t)stripesize, (intmax_t)offset, (intmax_t)length));
277 		if (length > stripesize)
278 			len = stripesize;
279 		else
280 			len = length;
281 	} while (length > 0);
282 }
283 
284 static void
285 g_stripe_done(struct bio *bp)
286 {
287 	struct g_stripe_softc *sc;
288 	struct bio *pbp;
289 
290 	pbp = bp->bio_parent;
291 	sc = pbp->bio_to->geom->softc;
292 	if (pbp->bio_error == 0)
293 		pbp->bio_error = bp->bio_error;
294 	pbp->bio_completed += bp->bio_completed;
295 	if (bp->bio_cmd == BIO_READ && bp->bio_caller1 != NULL) {
296 		g_stripe_copy(sc, bp->bio_data, bp->bio_caller1, bp->bio_offset,
297 		    bp->bio_length, 1);
298 		bp->bio_data = bp->bio_caller1;
299 		bp->bio_caller1 = NULL;
300 	}
301 	g_destroy_bio(bp);
302 	pbp->bio_inbed++;
303 	if (pbp->bio_children == pbp->bio_inbed) {
304 		if (pbp->bio_driver1 != NULL)
305 			uma_zfree(g_stripe_zone, pbp->bio_driver1);
306 		g_io_deliver(pbp, pbp->bio_error);
307 	}
308 }
309 
310 static int
311 g_stripe_start_fast(struct bio *bp, u_int no, off_t offset, off_t length)
312 {
313 	TAILQ_HEAD(, bio) queue = TAILQ_HEAD_INITIALIZER(queue);
314 	u_int nparts = 0, stripesize;
315 	struct g_stripe_softc *sc;
316 	char *addr, *data = NULL;
317 	struct bio *cbp;
318 	int error;
319 
320 	sc = bp->bio_to->geom->softc;
321 
322 	addr = bp->bio_data;
323 	stripesize = sc->sc_stripesize;
324 
325 	cbp = g_clone_bio(bp);
326 	if (cbp == NULL) {
327 		error = ENOMEM;
328 		goto failure;
329 	}
330 	TAILQ_INSERT_TAIL(&queue, cbp, bio_queue);
331 	nparts++;
332 	/*
333 	 * Fill in the component buf structure.
334 	 */
335 	cbp->bio_done = g_stripe_done;
336 	cbp->bio_offset = offset;
337 	cbp->bio_data = addr;
338 	cbp->bio_caller1 = NULL;
339 	cbp->bio_length = length;
340 	cbp->bio_caller2 = sc->sc_disks[no];
341 
342 	/* offset -= offset % stripesize; */
343 	offset -= offset & (stripesize - 1);
344 	addr += length;
345 	length = bp->bio_length - length;
346 	for (no++; length > 0; no++, length -= stripesize, addr += stripesize) {
347 		if (no > sc->sc_ndisks - 1) {
348 			no = 0;
349 			offset += stripesize;
350 		}
351 		if (nparts >= sc->sc_ndisks) {
352 			cbp = TAILQ_NEXT(cbp, bio_queue);
353 			if (cbp == NULL)
354 				cbp = TAILQ_FIRST(&queue);
355 			nparts++;
356 			/*
357 			 * Update bio structure.
358 			 */
359 			/*
360 			 * MIN() is in case when
361 			 * (bp->bio_length % sc->sc_stripesize) != 0.
362 			 */
363 			cbp->bio_length += MIN(stripesize, length);
364 			if (cbp->bio_caller1 == NULL) {
365 				cbp->bio_caller1 = cbp->bio_data;
366 				cbp->bio_data = NULL;
367 				if (data == NULL) {
368 					data = uma_zalloc(g_stripe_zone,
369 					    M_NOWAIT);
370 					if (data == NULL) {
371 						error = ENOMEM;
372 						goto failure;
373 					}
374 				}
375 			}
376 		} else {
377 			cbp = g_clone_bio(bp);
378 			if (cbp == NULL) {
379 				error = ENOMEM;
380 				goto failure;
381 			}
382 			TAILQ_INSERT_TAIL(&queue, cbp, bio_queue);
383 			nparts++;
384 			/*
385 			 * Fill in the component buf structure.
386 			 */
387 			cbp->bio_done = g_stripe_done;
388 			cbp->bio_offset = offset;
389 			cbp->bio_data = addr;
390 			cbp->bio_caller1 = NULL;
391 			/*
392 			 * MIN() is in case when
393 			 * (bp->bio_length % sc->sc_stripesize) != 0.
394 			 */
395 			cbp->bio_length = MIN(stripesize, length);
396 			cbp->bio_caller2 = sc->sc_disks[no];
397 		}
398 	}
399 	if (data != NULL)
400 		bp->bio_driver1 = data;
401 	/*
402 	 * Fire off all allocated requests!
403 	 */
404 	while ((cbp = TAILQ_FIRST(&queue)) != NULL) {
405 		struct g_consumer *cp;
406 
407 		TAILQ_REMOVE(&queue, cbp, bio_queue);
408 		cp = cbp->bio_caller2;
409 		cbp->bio_caller2 = NULL;
410 		cbp->bio_to = cp->provider;
411 		if (cbp->bio_caller1 != NULL) {
412 			cbp->bio_data = data;
413 			if (bp->bio_cmd == BIO_WRITE) {
414 				g_stripe_copy(sc, cbp->bio_caller1, data,
415 				    cbp->bio_offset, cbp->bio_length, 0);
416 			}
417 			data += cbp->bio_length;
418 		}
419 		G_STRIPE_LOGREQ(cbp, "Sending request.");
420 		g_io_request(cbp, cp);
421 	}
422 	return (0);
423 failure:
424 	if (data != NULL)
425 		uma_zfree(g_stripe_zone, data);
426 	while ((cbp = TAILQ_FIRST(&queue)) != NULL) {
427 		TAILQ_REMOVE(&queue, cbp, bio_queue);
428 		if (cbp->bio_caller1 != NULL) {
429 			cbp->bio_data = cbp->bio_caller1;
430 			cbp->bio_caller1 = NULL;
431 		}
432 		bp->bio_children--;
433 		g_destroy_bio(cbp);
434 	}
435 	return (error);
436 }
437 
438 static int
439 g_stripe_start_economic(struct bio *bp, u_int no, off_t offset, off_t length)
440 {
441 	TAILQ_HEAD(, bio) queue = TAILQ_HEAD_INITIALIZER(queue);
442 	struct g_stripe_softc *sc;
443 	uint32_t stripesize;
444 	struct bio *cbp;
445 	char *addr;
446 	int error;
447 
448 	sc = bp->bio_to->geom->softc;
449 
450 	addr = bp->bio_data;
451 	stripesize = sc->sc_stripesize;
452 
453 	cbp = g_clone_bio(bp);
454 	if (cbp == NULL) {
455 		error = ENOMEM;
456 		goto failure;
457 	}
458 	TAILQ_INSERT_TAIL(&queue, cbp, bio_queue);
459 	/*
460 	 * Fill in the component buf structure.
461 	 */
462 	cbp->bio_done = g_std_done;
463 	cbp->bio_offset = offset;
464 	cbp->bio_data = addr;
465 	cbp->bio_length = length;
466 	cbp->bio_caller2 = sc->sc_disks[no];
467 
468 	/* offset -= offset % stripesize; */
469 	offset -= offset & (stripesize - 1);
470 	addr += length;
471 	length = bp->bio_length - length;
472 	for (no++; length > 0; no++, length -= stripesize, addr += stripesize) {
473 		if (no > sc->sc_ndisks - 1) {
474 			no = 0;
475 			offset += stripesize;
476 		}
477 		cbp = g_clone_bio(bp);
478 		if (cbp == NULL) {
479 			error = ENOMEM;
480 			goto failure;
481 		}
482 		TAILQ_INSERT_TAIL(&queue, cbp, bio_queue);
483 
484 		/*
485 		 * Fill in the component buf structure.
486 		 */
487 		cbp->bio_done = g_std_done;
488 		cbp->bio_offset = offset;
489 		cbp->bio_data = addr;
490 		/*
491 		 * MIN() is in case when
492 		 * (bp->bio_length % sc->sc_stripesize) != 0.
493 		 */
494 		cbp->bio_length = MIN(stripesize, length);
495 
496 		cbp->bio_caller2 = sc->sc_disks[no];
497 	}
498 	/*
499 	 * Fire off all allocated requests!
500 	 */
501 	while ((cbp = TAILQ_FIRST(&queue)) != NULL) {
502 		struct g_consumer *cp;
503 
504 		TAILQ_REMOVE(&queue, cbp, bio_queue);
505 		cp = cbp->bio_caller2;
506 		cbp->bio_caller2 = NULL;
507 		cbp->bio_to = cp->provider;
508 		G_STRIPE_LOGREQ(cbp, "Sending request.");
509 		g_io_request(cbp, cp);
510 	}
511 	return (0);
512 failure:
513 	while ((cbp = TAILQ_FIRST(&queue)) != NULL) {
514 		TAILQ_REMOVE(&queue, cbp, bio_queue);
515 		bp->bio_children--;
516 		g_destroy_bio(cbp);
517 	}
518 	return (error);
519 }
520 
521 static void
522 g_stripe_flush(struct g_stripe_softc *sc, struct bio *bp)
523 {
524 	struct bio_queue_head queue;
525 	struct g_consumer *cp;
526 	struct bio *cbp;
527 	u_int no;
528 
529 	bioq_init(&queue);
530 	for (no = 0; no < sc->sc_ndisks; no++) {
531 		cbp = g_clone_bio(bp);
532 		if (cbp == NULL) {
533 			for (cbp = bioq_first(&queue); cbp != NULL;
534 			    cbp = bioq_first(&queue)) {
535 				bioq_remove(&queue, cbp);
536 				g_destroy_bio(cbp);
537 			}
538 			if (bp->bio_error == 0)
539 				bp->bio_error = ENOMEM;
540 			g_io_deliver(bp, bp->bio_error);
541 			return;
542 		}
543 		bioq_insert_tail(&queue, cbp);
544 		cbp->bio_done = g_std_done;
545 		cbp->bio_caller1 = sc->sc_disks[no];
546 		cbp->bio_to = sc->sc_disks[no]->provider;
547 	}
548 	for (cbp = bioq_first(&queue); cbp != NULL; cbp = bioq_first(&queue)) {
549 		bioq_remove(&queue, cbp);
550 		G_STRIPE_LOGREQ(cbp, "Sending request.");
551 		cp = cbp->bio_caller1;
552 		cbp->bio_caller1 = NULL;
553 		g_io_request(cbp, cp);
554 	}
555 }
556 
557 static void
558 g_stripe_start(struct bio *bp)
559 {
560 	off_t offset, start, length, nstripe;
561 	struct g_stripe_softc *sc;
562 	u_int no, stripesize;
563 	int error, fast = 0;
564 
565 	sc = bp->bio_to->geom->softc;
566 	/*
567 	 * If sc == NULL, provider's error should be set and g_stripe_start()
568 	 * should not be called at all.
569 	 */
570 	KASSERT(sc != NULL,
571 	    ("Provider's error should be set (error=%d)(device=%s).",
572 	    bp->bio_to->error, bp->bio_to->name));
573 
574 	G_STRIPE_LOGREQ(bp, "Request received.");
575 
576 	switch (bp->bio_cmd) {
577 	case BIO_READ:
578 	case BIO_WRITE:
579 	case BIO_DELETE:
580 		break;
581 	case BIO_FLUSH:
582 		g_stripe_flush(sc, bp);
583 		return;
584 	case BIO_GETATTR:
585 		/* To which provider it should be delivered? */
586 	default:
587 		g_io_deliver(bp, EOPNOTSUPP);
588 		return;
589 	}
590 
591 	stripesize = sc->sc_stripesize;
592 
593 	/*
594 	 * Calculations are quite messy, but fast I hope.
595 	 */
596 
597 	/* Stripe number. */
598 	/* nstripe = bp->bio_offset / stripesize; */
599 	nstripe = bp->bio_offset >> (off_t)sc->sc_stripebits;
600 	/* Disk number. */
601 	no = nstripe % sc->sc_ndisks;
602 	/* Start position in stripe. */
603 	/* start = bp->bio_offset % stripesize; */
604 	start = bp->bio_offset & (stripesize - 1);
605 	/* Start position in disk. */
606 	/* offset = (nstripe / sc->sc_ndisks) * stripesize + start; */
607 	offset = ((nstripe / sc->sc_ndisks) << sc->sc_stripebits) + start;
608 	/* Length of data to operate. */
609 	length = MIN(bp->bio_length, stripesize - start);
610 
611 	/*
612 	 * Do use "fast" mode when:
613 	 * 1. "Fast" mode is ON.
614 	 * and
615 	 * 2. Request size is less than or equal to MAXPHYS,
616 	 *    which should always be true.
617 	 * and
618 	 * 3. Request size is bigger than stripesize * ndisks. If it isn't,
619 	 *    there will be no need to send more than one I/O request to
620 	 *    a provider, so there is nothing to optmize.
621 	 */
622 	if (g_stripe_fast && bp->bio_length <= MAXPHYS &&
623 	    bp->bio_length >= stripesize * sc->sc_ndisks) {
624 		fast = 1;
625 	}
626 	error = 0;
627 	if (fast) {
628 		error = g_stripe_start_fast(bp, no, offset, length);
629 		if (error != 0)
630 			g_stripe_fast_failed++;
631 	}
632 	/*
633 	 * Do use "economic" when:
634 	 * 1. "Economic" mode is ON.
635 	 * or
636 	 * 2. "Fast" mode failed. It can only failed if there is no memory.
637 	 */
638 	if (!fast || error != 0)
639 		error = g_stripe_start_economic(bp, no, offset, length);
640 	if (error != 0) {
641 		if (bp->bio_error == 0)
642 			bp->bio_error = error;
643 		g_io_deliver(bp, bp->bio_error);
644 	}
645 }
646 
647 static void
648 g_stripe_check_and_run(struct g_stripe_softc *sc)
649 {
650 	off_t mediasize, ms;
651 	u_int no, sectorsize = 0;
652 
653 	if (g_stripe_nvalid(sc) != sc->sc_ndisks)
654 		return;
655 
656 	sc->sc_provider = g_new_providerf(sc->sc_geom, "stripe/%s",
657 	    sc->sc_name);
658 	/*
659 	 * Find the smallest disk.
660 	 */
661 	mediasize = sc->sc_disks[0]->provider->mediasize;
662 	if (sc->sc_type == G_STRIPE_TYPE_AUTOMATIC)
663 		mediasize -= sc->sc_disks[0]->provider->sectorsize;
664 	mediasize -= mediasize % sc->sc_stripesize;
665 	sectorsize = sc->sc_disks[0]->provider->sectorsize;
666 	for (no = 1; no < sc->sc_ndisks; no++) {
667 		ms = sc->sc_disks[no]->provider->mediasize;
668 		if (sc->sc_type == G_STRIPE_TYPE_AUTOMATIC)
669 			ms -= sc->sc_disks[no]->provider->sectorsize;
670 		ms -= ms % sc->sc_stripesize;
671 		if (ms < mediasize)
672 			mediasize = ms;
673 		sectorsize = lcm(sectorsize,
674 		    sc->sc_disks[no]->provider->sectorsize);
675 	}
676 	sc->sc_provider->sectorsize = sectorsize;
677 	sc->sc_provider->mediasize = mediasize * sc->sc_ndisks;
678 	g_error_provider(sc->sc_provider, 0);
679 
680 	G_STRIPE_DEBUG(0, "Device %s activated.", sc->sc_name);
681 }
682 
683 static int
684 g_stripe_read_metadata(struct g_consumer *cp, struct g_stripe_metadata *md)
685 {
686 	struct g_provider *pp;
687 	u_char *buf;
688 	int error;
689 
690 	g_topology_assert();
691 
692 	error = g_access(cp, 1, 0, 0);
693 	if (error != 0)
694 		return (error);
695 	pp = cp->provider;
696 	g_topology_unlock();
697 	buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
698 	    &error);
699 	g_topology_lock();
700 	g_access(cp, -1, 0, 0);
701 	if (buf == NULL)
702 		return (error);
703 
704 	/* Decode metadata. */
705 	stripe_metadata_decode(buf, md);
706 	g_free(buf);
707 
708 	return (0);
709 }
710 
711 /*
712  * Add disk to given device.
713  */
714 static int
715 g_stripe_add_disk(struct g_stripe_softc *sc, struct g_provider *pp, u_int no)
716 {
717 	struct g_consumer *cp, *fcp;
718 	struct g_geom *gp;
719 	int error;
720 
721 	/* Metadata corrupted? */
722 	if (no >= sc->sc_ndisks)
723 		return (EINVAL);
724 
725 	/* Check if disk is not already attached. */
726 	if (sc->sc_disks[no] != NULL)
727 		return (EEXIST);
728 
729 	gp = sc->sc_geom;
730 	fcp = LIST_FIRST(&gp->consumer);
731 
732 	cp = g_new_consumer(gp);
733 	error = g_attach(cp, pp);
734 	if (error != 0) {
735 		g_destroy_consumer(cp);
736 		return (error);
737 	}
738 
739 	if (fcp != NULL && (fcp->acr > 0 || fcp->acw > 0 || fcp->ace > 0)) {
740 		error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
741 		if (error != 0) {
742 			g_detach(cp);
743 			g_destroy_consumer(cp);
744 			return (error);
745 		}
746 	}
747 	if (sc->sc_type == G_STRIPE_TYPE_AUTOMATIC) {
748 		struct g_stripe_metadata md;
749 
750 		/* Reread metadata. */
751 		error = g_stripe_read_metadata(cp, &md);
752 		if (error != 0)
753 			goto fail;
754 
755 		if (strcmp(md.md_magic, G_STRIPE_MAGIC) != 0 ||
756 		    strcmp(md.md_name, sc->sc_name) != 0 ||
757 		    md.md_id != sc->sc_id) {
758 			G_STRIPE_DEBUG(0, "Metadata on %s changed.", pp->name);
759 			goto fail;
760 		}
761 	}
762 
763 	cp->private = sc;
764 	cp->index = no;
765 	sc->sc_disks[no] = cp;
766 
767 	G_STRIPE_DEBUG(0, "Disk %s attached to %s.", pp->name, sc->sc_name);
768 
769 	g_stripe_check_and_run(sc);
770 
771 	return (0);
772 fail:
773 	if (fcp != NULL && (fcp->acr > 0 || fcp->acw > 0 || fcp->ace > 0))
774 		g_access(cp, -fcp->acr, -fcp->acw, -fcp->ace);
775 	g_detach(cp);
776 	g_destroy_consumer(cp);
777 	return (error);
778 }
779 
780 static struct g_geom *
781 g_stripe_create(struct g_class *mp, const struct g_stripe_metadata *md,
782     u_int type)
783 {
784 	struct g_stripe_softc *sc;
785 	struct g_geom *gp;
786 	u_int no;
787 
788 	G_STRIPE_DEBUG(1, "Creating device %s (id=%u).", md->md_name,
789 	    md->md_id);
790 
791 	/* Two disks is minimum. */
792 	if (md->md_all < 2) {
793 		G_STRIPE_DEBUG(0, "Too few disks defined for %s.", md->md_name);
794 		return (NULL);
795 	}
796 #if 0
797 	/* Stripe size have to be grater than or equal to sector size. */
798 	if (md->md_stripesize < sectorsize) {
799 		G_STRIPE_DEBUG(0, "Invalid stripe size for %s.", md->md_name);
800 		return (NULL);
801 	}
802 #endif
803 	/* Stripe size have to be power of 2. */
804 	if (!powerof2(md->md_stripesize)) {
805 		G_STRIPE_DEBUG(0, "Invalid stripe size for %s.", md->md_name);
806 		return (NULL);
807 	}
808 
809 	/* Check for duplicate unit */
810 	LIST_FOREACH(gp, &mp->geom, geom) {
811 		sc = gp->softc;
812 		if (sc != NULL && strcmp(sc->sc_name, md->md_name) == 0) {
813 			G_STRIPE_DEBUG(0, "Device %s already configured.",
814 			    sc->sc_name);
815 			return (NULL);
816 		}
817 	}
818 	gp = g_new_geomf(mp, "%s", md->md_name);
819 	gp->softc = NULL;	/* for a moment */
820 
821 	sc = malloc(sizeof(*sc), M_STRIPE, M_WAITOK | M_ZERO);
822 	gp->start = g_stripe_start;
823 	gp->spoiled = g_stripe_orphan;
824 	gp->orphan = g_stripe_orphan;
825 	gp->access = g_stripe_access;
826 	gp->dumpconf = g_stripe_dumpconf;
827 
828 	sc->sc_id = md->md_id;
829 	sc->sc_stripesize = md->md_stripesize;
830 	sc->sc_stripebits = bitcount32(sc->sc_stripesize - 1);
831 	sc->sc_ndisks = md->md_all;
832 	sc->sc_disks = malloc(sizeof(struct g_consumer *) * sc->sc_ndisks,
833 	    M_STRIPE, M_WAITOK | M_ZERO);
834 	for (no = 0; no < sc->sc_ndisks; no++)
835 		sc->sc_disks[no] = NULL;
836 	sc->sc_type = type;
837 
838 	gp->softc = sc;
839 	sc->sc_geom = gp;
840 	sc->sc_provider = NULL;
841 
842 	G_STRIPE_DEBUG(0, "Device %s created (id=%u).", sc->sc_name, sc->sc_id);
843 
844 	return (gp);
845 }
846 
847 static int
848 g_stripe_destroy(struct g_stripe_softc *sc, boolean_t force)
849 {
850 	struct g_provider *pp;
851 	struct g_geom *gp;
852 	u_int no;
853 
854 	g_topology_assert();
855 
856 	if (sc == NULL)
857 		return (ENXIO);
858 
859 	pp = sc->sc_provider;
860 	if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
861 		if (force) {
862 			G_STRIPE_DEBUG(0, "Device %s is still open, so it "
863 			    "can't be definitely removed.", pp->name);
864 		} else {
865 			G_STRIPE_DEBUG(1,
866 			    "Device %s is still open (r%dw%de%d).", pp->name,
867 			    pp->acr, pp->acw, pp->ace);
868 			return (EBUSY);
869 		}
870 	}
871 
872 	for (no = 0; no < sc->sc_ndisks; no++) {
873 		if (sc->sc_disks[no] != NULL)
874 			g_stripe_remove_disk(sc->sc_disks[no]);
875 	}
876 
877 	gp = sc->sc_geom;
878 	gp->softc = NULL;
879 	KASSERT(sc->sc_provider == NULL, ("Provider still exists? (device=%s)",
880 	    gp->name));
881 	free(sc->sc_disks, M_STRIPE);
882 	free(sc, M_STRIPE);
883 
884 	pp = LIST_FIRST(&gp->provider);
885 	if (pp == NULL || (pp->acr == 0 && pp->acw == 0 && pp->ace == 0))
886 		G_STRIPE_DEBUG(0, "Device %s destroyed.", gp->name);
887 
888 	g_wither_geom(gp, ENXIO);
889 
890 	return (0);
891 }
892 
893 static int
894 g_stripe_destroy_geom(struct gctl_req *req __unused,
895     struct g_class *mp __unused, struct g_geom *gp)
896 {
897 	struct g_stripe_softc *sc;
898 
899 	sc = gp->softc;
900 	return (g_stripe_destroy(sc, 0));
901 }
902 
903 static struct g_geom *
904 g_stripe_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
905 {
906 	struct g_stripe_metadata md;
907 	struct g_stripe_softc *sc;
908 	struct g_consumer *cp;
909 	struct g_geom *gp;
910 	int error;
911 
912 	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
913 	g_topology_assert();
914 
915 	/* Skip providers that are already open for writing. */
916 	if (pp->acw > 0)
917 		return (NULL);
918 
919 	G_STRIPE_DEBUG(3, "Tasting %s.", pp->name);
920 
921 	gp = g_new_geomf(mp, "stripe:taste");
922 	gp->start = g_stripe_start;
923 	gp->access = g_stripe_access;
924 	gp->orphan = g_stripe_orphan;
925 	cp = g_new_consumer(gp);
926 	g_attach(cp, pp);
927 	error = g_stripe_read_metadata(cp, &md);
928 	g_detach(cp);
929 	g_destroy_consumer(cp);
930 	g_destroy_geom(gp);
931 	if (error != 0)
932 		return (NULL);
933 	gp = NULL;
934 
935 	if (strcmp(md.md_magic, G_STRIPE_MAGIC) != 0)
936 		return (NULL);
937 	if (md.md_version > G_STRIPE_VERSION) {
938 		printf("geom_stripe.ko module is too old to handle %s.\n",
939 		    pp->name);
940 		return (NULL);
941 	}
942 	/*
943 	 * Backward compatibility:
944 	 */
945 	/* There was no md_provider field in earlier versions of metadata. */
946 	if (md.md_version < 2)
947 		bzero(md.md_provider, sizeof(md.md_provider));
948 	/* There was no md_provsize field in earlier versions of metadata. */
949 	if (md.md_version < 3)
950 		md.md_provsize = pp->mediasize;
951 
952 	if (md.md_provider[0] != '\0' && strcmp(md.md_provider, pp->name) != 0)
953 		return (NULL);
954 	if (md.md_provsize != pp->mediasize)
955 		return (NULL);
956 
957 	/*
958 	 * Let's check if device already exists.
959 	 */
960 	sc = NULL;
961 	LIST_FOREACH(gp, &mp->geom, geom) {
962 		sc = gp->softc;
963 		if (sc == NULL)
964 			continue;
965 		if (sc->sc_type != G_STRIPE_TYPE_AUTOMATIC)
966 			continue;
967 		if (strcmp(md.md_name, sc->sc_name) != 0)
968 			continue;
969 		if (md.md_id != sc->sc_id)
970 			continue;
971 		break;
972 	}
973 	if (gp != NULL) {
974 		G_STRIPE_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
975 		error = g_stripe_add_disk(sc, pp, md.md_no);
976 		if (error != 0) {
977 			G_STRIPE_DEBUG(0,
978 			    "Cannot add disk %s to %s (error=%d).", pp->name,
979 			    gp->name, error);
980 			return (NULL);
981 		}
982 	} else {
983 		gp = g_stripe_create(mp, &md, G_STRIPE_TYPE_AUTOMATIC);
984 		if (gp == NULL) {
985 			G_STRIPE_DEBUG(0, "Cannot create device %s.",
986 			    md.md_name);
987 			return (NULL);
988 		}
989 		sc = gp->softc;
990 		G_STRIPE_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
991 		error = g_stripe_add_disk(sc, pp, md.md_no);
992 		if (error != 0) {
993 			G_STRIPE_DEBUG(0,
994 			    "Cannot add disk %s to %s (error=%d).", pp->name,
995 			    gp->name, error);
996 			g_stripe_destroy(sc, 1);
997 			return (NULL);
998 		}
999 	}
1000 
1001 	return (gp);
1002 }
1003 
1004 static void
1005 g_stripe_ctl_create(struct gctl_req *req, struct g_class *mp)
1006 {
1007 	u_int attached, no;
1008 	struct g_stripe_metadata md;
1009 	struct g_provider *pp;
1010 	struct g_stripe_softc *sc;
1011 	struct g_geom *gp;
1012 	struct sbuf *sb;
1013 	intmax_t *stripesize;
1014 	const char *name;
1015 	char param[16];
1016 	int *nargs;
1017 
1018 	g_topology_assert();
1019 	nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
1020 	if (nargs == NULL) {
1021 		gctl_error(req, "No '%s' argument.", "nargs");
1022 		return;
1023 	}
1024 	if (*nargs <= 2) {
1025 		gctl_error(req, "Too few arguments.");
1026 		return;
1027 	}
1028 
1029 	strlcpy(md.md_magic, G_STRIPE_MAGIC, sizeof(md.md_magic));
1030 	md.md_version = G_STRIPE_VERSION;
1031 	name = gctl_get_asciiparam(req, "arg0");
1032 	if (name == NULL) {
1033 		gctl_error(req, "No 'arg%u' argument.", 0);
1034 		return;
1035 	}
1036 	strlcpy(md.md_name, name, sizeof(md.md_name));
1037 	md.md_id = arc4random();
1038 	md.md_no = 0;
1039 	md.md_all = *nargs - 1;
1040 	stripesize = gctl_get_paraml(req, "stripesize", sizeof(*stripesize));
1041 	if (stripesize == NULL) {
1042 		gctl_error(req, "No '%s' argument.", "stripesize");
1043 		return;
1044 	}
1045 	md.md_stripesize = *stripesize;
1046 	bzero(md.md_provider, sizeof(md.md_provider));
1047 	/* This field is not important here. */
1048 	md.md_provsize = 0;
1049 
1050 	/* Check all providers are valid */
1051 	for (no = 1; no < *nargs; no++) {
1052 		snprintf(param, sizeof(param), "arg%u", no);
1053 		name = gctl_get_asciiparam(req, param);
1054 		if (name == NULL) {
1055 			gctl_error(req, "No 'arg%u' argument.", no);
1056 			return;
1057 		}
1058 		if (strncmp(name, "/dev/", strlen("/dev/")) == 0)
1059 			name += strlen("/dev/");
1060 		pp = g_provider_by_name(name);
1061 		if (pp == NULL) {
1062 			G_STRIPE_DEBUG(1, "Disk %s is invalid.", name);
1063 			gctl_error(req, "Disk %s is invalid.", name);
1064 			return;
1065 		}
1066 	}
1067 
1068 	gp = g_stripe_create(mp, &md, G_STRIPE_TYPE_MANUAL);
1069 	if (gp == NULL) {
1070 		gctl_error(req, "Can't configure %s.", md.md_name);
1071 		return;
1072 	}
1073 
1074 	sc = gp->softc;
1075 	sb = sbuf_new_auto();
1076 	sbuf_printf(sb, "Can't attach disk(s) to %s:", gp->name);
1077 	for (attached = 0, no = 1; no < *nargs; no++) {
1078 		snprintf(param, sizeof(param), "arg%u", no);
1079 		name = gctl_get_asciiparam(req, param);
1080 		if (name == NULL) {
1081 			gctl_error(req, "No 'arg%u' argument.", no);
1082 			continue;
1083 		}
1084 		if (strncmp(name, "/dev/", strlen("/dev/")) == 0)
1085 			name += strlen("/dev/");
1086 		pp = g_provider_by_name(name);
1087 		KASSERT(pp != NULL, ("Provider %s disappear?!", name));
1088 		if (g_stripe_add_disk(sc, pp, no - 1) != 0) {
1089 			G_STRIPE_DEBUG(1, "Disk %u (%s) not attached to %s.",
1090 			    no, pp->name, gp->name);
1091 			sbuf_printf(sb, " %s", pp->name);
1092 			continue;
1093 		}
1094 		attached++;
1095 	}
1096 	sbuf_finish(sb);
1097 	if (md.md_all != attached) {
1098 		g_stripe_destroy(gp->softc, 1);
1099 		gctl_error(req, "%s", sbuf_data(sb));
1100 	}
1101 	sbuf_delete(sb);
1102 }
1103 
1104 static struct g_stripe_softc *
1105 g_stripe_find_device(struct g_class *mp, const char *name)
1106 {
1107 	struct g_stripe_softc *sc;
1108 	struct g_geom *gp;
1109 
1110 	LIST_FOREACH(gp, &mp->geom, geom) {
1111 		sc = gp->softc;
1112 		if (sc == NULL)
1113 			continue;
1114 		if (strcmp(sc->sc_name, name) == 0)
1115 			return (sc);
1116 	}
1117 	return (NULL);
1118 }
1119 
1120 static void
1121 g_stripe_ctl_destroy(struct gctl_req *req, struct g_class *mp)
1122 {
1123 	struct g_stripe_softc *sc;
1124 	int *force, *nargs, error;
1125 	const char *name;
1126 	char param[16];
1127 	u_int i;
1128 
1129 	g_topology_assert();
1130 
1131 	nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
1132 	if (nargs == NULL) {
1133 		gctl_error(req, "No '%s' argument.", "nargs");
1134 		return;
1135 	}
1136 	if (*nargs <= 0) {
1137 		gctl_error(req, "Missing device(s).");
1138 		return;
1139 	}
1140 	force = gctl_get_paraml(req, "force", sizeof(*force));
1141 	if (force == NULL) {
1142 		gctl_error(req, "No '%s' argument.", "force");
1143 		return;
1144 	}
1145 
1146 	for (i = 0; i < (u_int)*nargs; i++) {
1147 		snprintf(param, sizeof(param), "arg%u", i);
1148 		name = gctl_get_asciiparam(req, param);
1149 		if (name == NULL) {
1150 			gctl_error(req, "No 'arg%u' argument.", i);
1151 			return;
1152 		}
1153 		sc = g_stripe_find_device(mp, name);
1154 		if (sc == NULL) {
1155 			gctl_error(req, "No such device: %s.", name);
1156 			return;
1157 		}
1158 		error = g_stripe_destroy(sc, *force);
1159 		if (error != 0) {
1160 			gctl_error(req, "Cannot destroy device %s (error=%d).",
1161 			    sc->sc_name, error);
1162 			return;
1163 		}
1164 	}
1165 }
1166 
1167 static void
1168 g_stripe_config(struct gctl_req *req, struct g_class *mp, const char *verb)
1169 {
1170 	uint32_t *version;
1171 
1172 	g_topology_assert();
1173 
1174 	version = gctl_get_paraml(req, "version", sizeof(*version));
1175 	if (version == NULL) {
1176 		gctl_error(req, "No '%s' argument.", "version");
1177 		return;
1178 	}
1179 	if (*version != G_STRIPE_VERSION) {
1180 		gctl_error(req, "Userland and kernel parts are out of sync.");
1181 		return;
1182 	}
1183 
1184 	if (strcmp(verb, "create") == 0) {
1185 		g_stripe_ctl_create(req, mp);
1186 		return;
1187 	} else if (strcmp(verb, "destroy") == 0 ||
1188 	    strcmp(verb, "stop") == 0) {
1189 		g_stripe_ctl_destroy(req, mp);
1190 		return;
1191 	}
1192 
1193 	gctl_error(req, "Unknown verb.");
1194 }
1195 
1196 static void
1197 g_stripe_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1198     struct g_consumer *cp, struct g_provider *pp)
1199 {
1200 	struct g_stripe_softc *sc;
1201 
1202 	sc = gp->softc;
1203 	if (sc == NULL)
1204 		return;
1205 	if (pp != NULL) {
1206 		/* Nothing here. */
1207 	} else if (cp != NULL) {
1208 		sbuf_printf(sb, "%s<Number>%u</Number>\n", indent,
1209 		    (u_int)cp->index);
1210 	} else {
1211 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)sc->sc_id);
1212 		sbuf_printf(sb, "%s<Stripesize>%u</Stripesize>\n", indent,
1213 		    (u_int)sc->sc_stripesize);
1214 		sbuf_printf(sb, "%s<Type>", indent);
1215 		switch (sc->sc_type) {
1216 		case G_STRIPE_TYPE_AUTOMATIC:
1217 			sbuf_printf(sb, "AUTOMATIC");
1218 			break;
1219 		case G_STRIPE_TYPE_MANUAL:
1220 			sbuf_printf(sb, "MANUAL");
1221 			break;
1222 		default:
1223 			sbuf_printf(sb, "UNKNOWN");
1224 			break;
1225 		}
1226 		sbuf_printf(sb, "</Type>\n");
1227 		sbuf_printf(sb, "%s<Status>Total=%u, Online=%u</Status>\n",
1228 		    indent, sc->sc_ndisks, g_stripe_nvalid(sc));
1229 		sbuf_printf(sb, "%s<State>", indent);
1230 		if (sc->sc_provider != NULL && sc->sc_provider->error == 0)
1231 			sbuf_printf(sb, "UP");
1232 		else
1233 			sbuf_printf(sb, "DOWN");
1234 		sbuf_printf(sb, "</State>\n");
1235 	}
1236 }
1237 
1238 DECLARE_GEOM_CLASS(g_stripe_class, g_stripe);
1239