xref: /freebsd/sys/geom/stripe/g_stripe.c (revision 3157ba21)
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 fail 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 	sc->sc_provider->stripesize = sc->sc_stripesize;
679 	sc->sc_provider->stripeoffset = 0;
680 	g_error_provider(sc->sc_provider, 0);
681 
682 	G_STRIPE_DEBUG(0, "Device %s activated.", sc->sc_name);
683 }
684 
685 static int
686 g_stripe_read_metadata(struct g_consumer *cp, struct g_stripe_metadata *md)
687 {
688 	struct g_provider *pp;
689 	u_char *buf;
690 	int error;
691 
692 	g_topology_assert();
693 
694 	error = g_access(cp, 1, 0, 0);
695 	if (error != 0)
696 		return (error);
697 	pp = cp->provider;
698 	g_topology_unlock();
699 	buf = g_read_data(cp, pp->mediasize - pp->sectorsize, pp->sectorsize,
700 	    &error);
701 	g_topology_lock();
702 	g_access(cp, -1, 0, 0);
703 	if (buf == NULL)
704 		return (error);
705 
706 	/* Decode metadata. */
707 	stripe_metadata_decode(buf, md);
708 	g_free(buf);
709 
710 	return (0);
711 }
712 
713 /*
714  * Add disk to given device.
715  */
716 static int
717 g_stripe_add_disk(struct g_stripe_softc *sc, struct g_provider *pp, u_int no)
718 {
719 	struct g_consumer *cp, *fcp;
720 	struct g_geom *gp;
721 	int error;
722 
723 	/* Metadata corrupted? */
724 	if (no >= sc->sc_ndisks)
725 		return (EINVAL);
726 
727 	/* Check if disk is not already attached. */
728 	if (sc->sc_disks[no] != NULL)
729 		return (EEXIST);
730 
731 	gp = sc->sc_geom;
732 	fcp = LIST_FIRST(&gp->consumer);
733 
734 	cp = g_new_consumer(gp);
735 	error = g_attach(cp, pp);
736 	if (error != 0) {
737 		g_destroy_consumer(cp);
738 		return (error);
739 	}
740 
741 	if (fcp != NULL && (fcp->acr > 0 || fcp->acw > 0 || fcp->ace > 0)) {
742 		error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
743 		if (error != 0) {
744 			g_detach(cp);
745 			g_destroy_consumer(cp);
746 			return (error);
747 		}
748 	}
749 	if (sc->sc_type == G_STRIPE_TYPE_AUTOMATIC) {
750 		struct g_stripe_metadata md;
751 
752 		/* Reread metadata. */
753 		error = g_stripe_read_metadata(cp, &md);
754 		if (error != 0)
755 			goto fail;
756 
757 		if (strcmp(md.md_magic, G_STRIPE_MAGIC) != 0 ||
758 		    strcmp(md.md_name, sc->sc_name) != 0 ||
759 		    md.md_id != sc->sc_id) {
760 			G_STRIPE_DEBUG(0, "Metadata on %s changed.", pp->name);
761 			goto fail;
762 		}
763 	}
764 
765 	cp->private = sc;
766 	cp->index = no;
767 	sc->sc_disks[no] = cp;
768 
769 	G_STRIPE_DEBUG(0, "Disk %s attached to %s.", pp->name, sc->sc_name);
770 
771 	g_stripe_check_and_run(sc);
772 
773 	return (0);
774 fail:
775 	if (fcp != NULL && (fcp->acr > 0 || fcp->acw > 0 || fcp->ace > 0))
776 		g_access(cp, -fcp->acr, -fcp->acw, -fcp->ace);
777 	g_detach(cp);
778 	g_destroy_consumer(cp);
779 	return (error);
780 }
781 
782 static struct g_geom *
783 g_stripe_create(struct g_class *mp, const struct g_stripe_metadata *md,
784     u_int type)
785 {
786 	struct g_stripe_softc *sc;
787 	struct g_geom *gp;
788 	u_int no;
789 
790 	G_STRIPE_DEBUG(1, "Creating device %s (id=%u).", md->md_name,
791 	    md->md_id);
792 
793 	/* Two disks is minimum. */
794 	if (md->md_all < 2) {
795 		G_STRIPE_DEBUG(0, "Too few disks defined for %s.", md->md_name);
796 		return (NULL);
797 	}
798 #if 0
799 	/* Stripe size have to be grater than or equal to sector size. */
800 	if (md->md_stripesize < sectorsize) {
801 		G_STRIPE_DEBUG(0, "Invalid stripe size for %s.", md->md_name);
802 		return (NULL);
803 	}
804 #endif
805 	/* Stripe size have to be power of 2. */
806 	if (!powerof2(md->md_stripesize)) {
807 		G_STRIPE_DEBUG(0, "Invalid stripe size for %s.", md->md_name);
808 		return (NULL);
809 	}
810 
811 	/* Check for duplicate unit */
812 	LIST_FOREACH(gp, &mp->geom, geom) {
813 		sc = gp->softc;
814 		if (sc != NULL && strcmp(sc->sc_name, md->md_name) == 0) {
815 			G_STRIPE_DEBUG(0, "Device %s already configured.",
816 			    sc->sc_name);
817 			return (NULL);
818 		}
819 	}
820 	gp = g_new_geomf(mp, "%s", md->md_name);
821 	gp->softc = NULL;	/* for a moment */
822 
823 	sc = malloc(sizeof(*sc), M_STRIPE, M_WAITOK | M_ZERO);
824 	gp->start = g_stripe_start;
825 	gp->spoiled = g_stripe_orphan;
826 	gp->orphan = g_stripe_orphan;
827 	gp->access = g_stripe_access;
828 	gp->dumpconf = g_stripe_dumpconf;
829 
830 	sc->sc_id = md->md_id;
831 	sc->sc_stripesize = md->md_stripesize;
832 	sc->sc_stripebits = bitcount32(sc->sc_stripesize - 1);
833 	sc->sc_ndisks = md->md_all;
834 	sc->sc_disks = malloc(sizeof(struct g_consumer *) * sc->sc_ndisks,
835 	    M_STRIPE, M_WAITOK | M_ZERO);
836 	for (no = 0; no < sc->sc_ndisks; no++)
837 		sc->sc_disks[no] = NULL;
838 	sc->sc_type = type;
839 
840 	gp->softc = sc;
841 	sc->sc_geom = gp;
842 	sc->sc_provider = NULL;
843 
844 	G_STRIPE_DEBUG(0, "Device %s created (id=%u).", sc->sc_name, sc->sc_id);
845 
846 	return (gp);
847 }
848 
849 static int
850 g_stripe_destroy(struct g_stripe_softc *sc, boolean_t force)
851 {
852 	struct g_provider *pp;
853 	struct g_geom *gp;
854 	u_int no;
855 
856 	g_topology_assert();
857 
858 	if (sc == NULL)
859 		return (ENXIO);
860 
861 	pp = sc->sc_provider;
862 	if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
863 		if (force) {
864 			G_STRIPE_DEBUG(0, "Device %s is still open, so it "
865 			    "can't be definitely removed.", pp->name);
866 		} else {
867 			G_STRIPE_DEBUG(1,
868 			    "Device %s is still open (r%dw%de%d).", pp->name,
869 			    pp->acr, pp->acw, pp->ace);
870 			return (EBUSY);
871 		}
872 	}
873 
874 	for (no = 0; no < sc->sc_ndisks; no++) {
875 		if (sc->sc_disks[no] != NULL)
876 			g_stripe_remove_disk(sc->sc_disks[no]);
877 	}
878 
879 	gp = sc->sc_geom;
880 	gp->softc = NULL;
881 	KASSERT(sc->sc_provider == NULL, ("Provider still exists? (device=%s)",
882 	    gp->name));
883 	free(sc->sc_disks, M_STRIPE);
884 	free(sc, M_STRIPE);
885 
886 	pp = LIST_FIRST(&gp->provider);
887 	if (pp == NULL || (pp->acr == 0 && pp->acw == 0 && pp->ace == 0))
888 		G_STRIPE_DEBUG(0, "Device %s destroyed.", gp->name);
889 
890 	g_wither_geom(gp, ENXIO);
891 
892 	return (0);
893 }
894 
895 static int
896 g_stripe_destroy_geom(struct gctl_req *req __unused,
897     struct g_class *mp __unused, struct g_geom *gp)
898 {
899 	struct g_stripe_softc *sc;
900 
901 	sc = gp->softc;
902 	return (g_stripe_destroy(sc, 0));
903 }
904 
905 static struct g_geom *
906 g_stripe_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
907 {
908 	struct g_stripe_metadata md;
909 	struct g_stripe_softc *sc;
910 	struct g_consumer *cp;
911 	struct g_geom *gp;
912 	int error;
913 
914 	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
915 	g_topology_assert();
916 
917 	/* Skip providers that are already open for writing. */
918 	if (pp->acw > 0)
919 		return (NULL);
920 
921 	G_STRIPE_DEBUG(3, "Tasting %s.", pp->name);
922 
923 	gp = g_new_geomf(mp, "stripe:taste");
924 	gp->start = g_stripe_start;
925 	gp->access = g_stripe_access;
926 	gp->orphan = g_stripe_orphan;
927 	cp = g_new_consumer(gp);
928 	g_attach(cp, pp);
929 	error = g_stripe_read_metadata(cp, &md);
930 	g_detach(cp);
931 	g_destroy_consumer(cp);
932 	g_destroy_geom(gp);
933 	if (error != 0)
934 		return (NULL);
935 	gp = NULL;
936 
937 	if (strcmp(md.md_magic, G_STRIPE_MAGIC) != 0)
938 		return (NULL);
939 	if (md.md_version > G_STRIPE_VERSION) {
940 		printf("geom_stripe.ko module is too old to handle %s.\n",
941 		    pp->name);
942 		return (NULL);
943 	}
944 	/*
945 	 * Backward compatibility:
946 	 */
947 	/* There was no md_provider field in earlier versions of metadata. */
948 	if (md.md_version < 2)
949 		bzero(md.md_provider, sizeof(md.md_provider));
950 	/* There was no md_provsize field in earlier versions of metadata. */
951 	if (md.md_version < 3)
952 		md.md_provsize = pp->mediasize;
953 
954 	if (md.md_provider[0] != '\0' && strcmp(md.md_provider, pp->name) != 0)
955 		return (NULL);
956 	if (md.md_provsize != pp->mediasize)
957 		return (NULL);
958 
959 	/*
960 	 * Let's check if device already exists.
961 	 */
962 	sc = NULL;
963 	LIST_FOREACH(gp, &mp->geom, geom) {
964 		sc = gp->softc;
965 		if (sc == NULL)
966 			continue;
967 		if (sc->sc_type != G_STRIPE_TYPE_AUTOMATIC)
968 			continue;
969 		if (strcmp(md.md_name, sc->sc_name) != 0)
970 			continue;
971 		if (md.md_id != sc->sc_id)
972 			continue;
973 		break;
974 	}
975 	if (gp != NULL) {
976 		G_STRIPE_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
977 		error = g_stripe_add_disk(sc, pp, md.md_no);
978 		if (error != 0) {
979 			G_STRIPE_DEBUG(0,
980 			    "Cannot add disk %s to %s (error=%d).", pp->name,
981 			    gp->name, error);
982 			return (NULL);
983 		}
984 	} else {
985 		gp = g_stripe_create(mp, &md, G_STRIPE_TYPE_AUTOMATIC);
986 		if (gp == NULL) {
987 			G_STRIPE_DEBUG(0, "Cannot create device %s.",
988 			    md.md_name);
989 			return (NULL);
990 		}
991 		sc = gp->softc;
992 		G_STRIPE_DEBUG(1, "Adding disk %s to %s.", pp->name, gp->name);
993 		error = g_stripe_add_disk(sc, pp, md.md_no);
994 		if (error != 0) {
995 			G_STRIPE_DEBUG(0,
996 			    "Cannot add disk %s to %s (error=%d).", pp->name,
997 			    gp->name, error);
998 			g_stripe_destroy(sc, 1);
999 			return (NULL);
1000 		}
1001 	}
1002 
1003 	return (gp);
1004 }
1005 
1006 static void
1007 g_stripe_ctl_create(struct gctl_req *req, struct g_class *mp)
1008 {
1009 	u_int attached, no;
1010 	struct g_stripe_metadata md;
1011 	struct g_provider *pp;
1012 	struct g_stripe_softc *sc;
1013 	struct g_geom *gp;
1014 	struct sbuf *sb;
1015 	intmax_t *stripesize;
1016 	const char *name;
1017 	char param[16];
1018 	int *nargs;
1019 
1020 	g_topology_assert();
1021 	nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
1022 	if (nargs == NULL) {
1023 		gctl_error(req, "No '%s' argument.", "nargs");
1024 		return;
1025 	}
1026 	if (*nargs <= 2) {
1027 		gctl_error(req, "Too few arguments.");
1028 		return;
1029 	}
1030 
1031 	strlcpy(md.md_magic, G_STRIPE_MAGIC, sizeof(md.md_magic));
1032 	md.md_version = G_STRIPE_VERSION;
1033 	name = gctl_get_asciiparam(req, "arg0");
1034 	if (name == NULL) {
1035 		gctl_error(req, "No 'arg%u' argument.", 0);
1036 		return;
1037 	}
1038 	strlcpy(md.md_name, name, sizeof(md.md_name));
1039 	md.md_id = arc4random();
1040 	md.md_no = 0;
1041 	md.md_all = *nargs - 1;
1042 	stripesize = gctl_get_paraml(req, "stripesize", sizeof(*stripesize));
1043 	if (stripesize == NULL) {
1044 		gctl_error(req, "No '%s' argument.", "stripesize");
1045 		return;
1046 	}
1047 	md.md_stripesize = *stripesize;
1048 	bzero(md.md_provider, sizeof(md.md_provider));
1049 	/* This field is not important here. */
1050 	md.md_provsize = 0;
1051 
1052 	/* Check all providers are valid */
1053 	for (no = 1; no < *nargs; no++) {
1054 		snprintf(param, sizeof(param), "arg%u", no);
1055 		name = gctl_get_asciiparam(req, param);
1056 		if (name == NULL) {
1057 			gctl_error(req, "No 'arg%u' argument.", no);
1058 			return;
1059 		}
1060 		if (strncmp(name, "/dev/", strlen("/dev/")) == 0)
1061 			name += strlen("/dev/");
1062 		pp = g_provider_by_name(name);
1063 		if (pp == NULL) {
1064 			G_STRIPE_DEBUG(1, "Disk %s is invalid.", name);
1065 			gctl_error(req, "Disk %s is invalid.", name);
1066 			return;
1067 		}
1068 	}
1069 
1070 	gp = g_stripe_create(mp, &md, G_STRIPE_TYPE_MANUAL);
1071 	if (gp == NULL) {
1072 		gctl_error(req, "Can't configure %s.", md.md_name);
1073 		return;
1074 	}
1075 
1076 	sc = gp->softc;
1077 	sb = sbuf_new_auto();
1078 	sbuf_printf(sb, "Can't attach disk(s) to %s:", gp->name);
1079 	for (attached = 0, no = 1; no < *nargs; no++) {
1080 		snprintf(param, sizeof(param), "arg%u", no);
1081 		name = gctl_get_asciiparam(req, param);
1082 		if (name == NULL) {
1083 			gctl_error(req, "No 'arg%u' argument.", no);
1084 			continue;
1085 		}
1086 		if (strncmp(name, "/dev/", strlen("/dev/")) == 0)
1087 			name += strlen("/dev/");
1088 		pp = g_provider_by_name(name);
1089 		KASSERT(pp != NULL, ("Provider %s disappear?!", name));
1090 		if (g_stripe_add_disk(sc, pp, no - 1) != 0) {
1091 			G_STRIPE_DEBUG(1, "Disk %u (%s) not attached to %s.",
1092 			    no, pp->name, gp->name);
1093 			sbuf_printf(sb, " %s", pp->name);
1094 			continue;
1095 		}
1096 		attached++;
1097 	}
1098 	sbuf_finish(sb);
1099 	if (md.md_all != attached) {
1100 		g_stripe_destroy(gp->softc, 1);
1101 		gctl_error(req, "%s", sbuf_data(sb));
1102 	}
1103 	sbuf_delete(sb);
1104 }
1105 
1106 static struct g_stripe_softc *
1107 g_stripe_find_device(struct g_class *mp, const char *name)
1108 {
1109 	struct g_stripe_softc *sc;
1110 	struct g_geom *gp;
1111 
1112 	LIST_FOREACH(gp, &mp->geom, geom) {
1113 		sc = gp->softc;
1114 		if (sc == NULL)
1115 			continue;
1116 		if (strcmp(sc->sc_name, name) == 0)
1117 			return (sc);
1118 	}
1119 	return (NULL);
1120 }
1121 
1122 static void
1123 g_stripe_ctl_destroy(struct gctl_req *req, struct g_class *mp)
1124 {
1125 	struct g_stripe_softc *sc;
1126 	int *force, *nargs, error;
1127 	const char *name;
1128 	char param[16];
1129 	u_int i;
1130 
1131 	g_topology_assert();
1132 
1133 	nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
1134 	if (nargs == NULL) {
1135 		gctl_error(req, "No '%s' argument.", "nargs");
1136 		return;
1137 	}
1138 	if (*nargs <= 0) {
1139 		gctl_error(req, "Missing device(s).");
1140 		return;
1141 	}
1142 	force = gctl_get_paraml(req, "force", sizeof(*force));
1143 	if (force == NULL) {
1144 		gctl_error(req, "No '%s' argument.", "force");
1145 		return;
1146 	}
1147 
1148 	for (i = 0; i < (u_int)*nargs; i++) {
1149 		snprintf(param, sizeof(param), "arg%u", i);
1150 		name = gctl_get_asciiparam(req, param);
1151 		if (name == NULL) {
1152 			gctl_error(req, "No 'arg%u' argument.", i);
1153 			return;
1154 		}
1155 		sc = g_stripe_find_device(mp, name);
1156 		if (sc == NULL) {
1157 			gctl_error(req, "No such device: %s.", name);
1158 			return;
1159 		}
1160 		error = g_stripe_destroy(sc, *force);
1161 		if (error != 0) {
1162 			gctl_error(req, "Cannot destroy device %s (error=%d).",
1163 			    sc->sc_name, error);
1164 			return;
1165 		}
1166 	}
1167 }
1168 
1169 static void
1170 g_stripe_config(struct gctl_req *req, struct g_class *mp, const char *verb)
1171 {
1172 	uint32_t *version;
1173 
1174 	g_topology_assert();
1175 
1176 	version = gctl_get_paraml(req, "version", sizeof(*version));
1177 	if (version == NULL) {
1178 		gctl_error(req, "No '%s' argument.", "version");
1179 		return;
1180 	}
1181 	if (*version != G_STRIPE_VERSION) {
1182 		gctl_error(req, "Userland and kernel parts are out of sync.");
1183 		return;
1184 	}
1185 
1186 	if (strcmp(verb, "create") == 0) {
1187 		g_stripe_ctl_create(req, mp);
1188 		return;
1189 	} else if (strcmp(verb, "destroy") == 0 ||
1190 	    strcmp(verb, "stop") == 0) {
1191 		g_stripe_ctl_destroy(req, mp);
1192 		return;
1193 	}
1194 
1195 	gctl_error(req, "Unknown verb.");
1196 }
1197 
1198 static void
1199 g_stripe_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
1200     struct g_consumer *cp, struct g_provider *pp)
1201 {
1202 	struct g_stripe_softc *sc;
1203 
1204 	sc = gp->softc;
1205 	if (sc == NULL)
1206 		return;
1207 	if (pp != NULL) {
1208 		/* Nothing here. */
1209 	} else if (cp != NULL) {
1210 		sbuf_printf(sb, "%s<Number>%u</Number>\n", indent,
1211 		    (u_int)cp->index);
1212 	} else {
1213 		sbuf_printf(sb, "%s<ID>%u</ID>\n", indent, (u_int)sc->sc_id);
1214 		sbuf_printf(sb, "%s<Stripesize>%u</Stripesize>\n", indent,
1215 		    (u_int)sc->sc_stripesize);
1216 		sbuf_printf(sb, "%s<Type>", indent);
1217 		switch (sc->sc_type) {
1218 		case G_STRIPE_TYPE_AUTOMATIC:
1219 			sbuf_printf(sb, "AUTOMATIC");
1220 			break;
1221 		case G_STRIPE_TYPE_MANUAL:
1222 			sbuf_printf(sb, "MANUAL");
1223 			break;
1224 		default:
1225 			sbuf_printf(sb, "UNKNOWN");
1226 			break;
1227 		}
1228 		sbuf_printf(sb, "</Type>\n");
1229 		sbuf_printf(sb, "%s<Status>Total=%u, Online=%u</Status>\n",
1230 		    indent, sc->sc_ndisks, g_stripe_nvalid(sc));
1231 		sbuf_printf(sb, "%s<State>", indent);
1232 		if (sc->sc_provider != NULL && sc->sc_provider->error == 0)
1233 			sbuf_printf(sb, "UP");
1234 		else
1235 			sbuf_printf(sb, "DOWN");
1236 		sbuf_printf(sb, "</State>\n");
1237 	}
1238 }
1239 
1240 DECLARE_GEOM_CLASS(g_stripe_class, g_stripe);
1241