xref: /freebsd/sys/geom/geom_io.c (revision f0a75d274af375d15b97b830966b99a02b7db911)
1 /*-
2  * Copyright (c) 2002 Poul-Henning Kamp
3  * Copyright (c) 2002 Networks Associates Technology, Inc.
4  * All rights reserved.
5  *
6  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
7  * and NAI Labs, the Security Research Division of Network Associates, Inc.
8  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
9  * DARPA CHATS research program.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. The names of the authors may not be used to endorse or promote
20  *    products derived from this software without specific prior written
21  *    permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/kernel.h>
42 #include <sys/malloc.h>
43 #include <sys/bio.h>
44 #include <sys/ktr.h>
45 #include <sys/proc.h>
46 #include <sys/stack.h>
47 
48 #include <sys/errno.h>
49 #include <geom/geom.h>
50 #include <geom/geom_int.h>
51 #include <sys/devicestat.h>
52 
53 #include <vm/uma.h>
54 
55 static struct g_bioq g_bio_run_down;
56 static struct g_bioq g_bio_run_up;
57 static struct g_bioq g_bio_run_task;
58 
59 static u_int pace;
60 static uma_zone_t	biozone;
61 
62 #include <machine/atomic.h>
63 
64 static void
65 g_bioq_lock(struct g_bioq *bq)
66 {
67 
68 	mtx_lock(&bq->bio_queue_lock);
69 }
70 
71 static void
72 g_bioq_unlock(struct g_bioq *bq)
73 {
74 
75 	mtx_unlock(&bq->bio_queue_lock);
76 }
77 
78 #if 0
79 static void
80 g_bioq_destroy(struct g_bioq *bq)
81 {
82 
83 	mtx_destroy(&bq->bio_queue_lock);
84 }
85 #endif
86 
87 static void
88 g_bioq_init(struct g_bioq *bq)
89 {
90 
91 	TAILQ_INIT(&bq->bio_queue);
92 	mtx_init(&bq->bio_queue_lock, "bio queue", NULL, MTX_DEF);
93 }
94 
95 static struct bio *
96 g_bioq_first(struct g_bioq *bq)
97 {
98 	struct bio *bp;
99 
100 	bp = TAILQ_FIRST(&bq->bio_queue);
101 	if (bp != NULL) {
102 		KASSERT((bp->bio_flags & BIO_ONQUEUE),
103 		    ("Bio not on queue bp=%p target %p", bp, bq));
104 		bp->bio_flags &= ~BIO_ONQUEUE;
105 		TAILQ_REMOVE(&bq->bio_queue, bp, bio_queue);
106 		bq->bio_queue_length--;
107 	}
108 	return (bp);
109 }
110 
111 struct bio *
112 g_new_bio(void)
113 {
114 	struct bio *bp;
115 
116 	bp = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
117 #ifdef KTR
118 	if (KTR_COMPILE & KTR_GEOM) {
119 		struct stack st;
120 
121 		CTR1(KTR_GEOM, "g_new_bio(): %p", bp);
122 		stack_save(&st);
123 		CTRSTACK(KTR_GEOM, &st, 3, 0);
124 	}
125 #endif
126 	return (bp);
127 }
128 
129 struct bio *
130 g_alloc_bio(void)
131 {
132 	struct bio *bp;
133 
134 	bp = uma_zalloc(biozone, M_WAITOK | M_ZERO);
135 #ifdef KTR
136 	if (KTR_COMPILE & KTR_GEOM) {
137 		struct stack st;
138 
139 		CTR1(KTR_GEOM, "g_alloc_bio(): %p", bp);
140 		stack_save(&st);
141 		CTRSTACK(KTR_GEOM, &st, 3, 0);
142 	}
143 #endif
144 	return (bp);
145 }
146 
147 void
148 g_destroy_bio(struct bio *bp)
149 {
150 #ifdef KTR
151 	if (KTR_COMPILE & KTR_GEOM) {
152 		struct stack st;
153 
154 		CTR1(KTR_GEOM, "g_destroy_bio(): %p", bp);
155 		stack_save(&st);
156 		CTRSTACK(KTR_GEOM, &st, 3, 0);
157 	}
158 #endif
159 	uma_zfree(biozone, bp);
160 }
161 
162 struct bio *
163 g_clone_bio(struct bio *bp)
164 {
165 	struct bio *bp2;
166 
167 	bp2 = uma_zalloc(biozone, M_NOWAIT | M_ZERO);
168 	if (bp2 != NULL) {
169 		bp2->bio_parent = bp;
170 		bp2->bio_cmd = bp->bio_cmd;
171 		bp2->bio_length = bp->bio_length;
172 		bp2->bio_offset = bp->bio_offset;
173 		bp2->bio_data = bp->bio_data;
174 		bp2->bio_attribute = bp->bio_attribute;
175 		bp->bio_children++;
176 	}
177 #ifdef KTR
178 	if (KTR_COMPILE & KTR_GEOM) {
179 		struct stack st;
180 
181 		CTR2(KTR_GEOM, "g_clone_bio(%p): %p", bp, bp2);
182 		stack_save(&st);
183 		CTRSTACK(KTR_GEOM, &st, 3, 0);
184 	}
185 #endif
186 	return(bp2);
187 }
188 
189 struct bio *
190 g_duplicate_bio(struct bio *bp)
191 {
192 	struct bio *bp2;
193 
194 	bp2 = uma_zalloc(biozone, M_WAITOK | M_ZERO);
195 	bp2->bio_parent = bp;
196 	bp2->bio_cmd = bp->bio_cmd;
197 	bp2->bio_length = bp->bio_length;
198 	bp2->bio_offset = bp->bio_offset;
199 	bp2->bio_data = bp->bio_data;
200 	bp2->bio_attribute = bp->bio_attribute;
201 	bp->bio_children++;
202 #ifdef KTR
203 	if (KTR_COMPILE & KTR_GEOM) {
204 		struct stack st;
205 
206 		CTR2(KTR_GEOM, "g_duplicate_bio(%p): %p", bp, bp2);
207 		stack_save(&st);
208 		CTRSTACK(KTR_GEOM, &st, 3, 0);
209 	}
210 #endif
211 	return(bp2);
212 }
213 
214 void
215 g_io_init()
216 {
217 
218 	g_bioq_init(&g_bio_run_down);
219 	g_bioq_init(&g_bio_run_up);
220 	g_bioq_init(&g_bio_run_task);
221 	biozone = uma_zcreate("g_bio", sizeof (struct bio),
222 	    NULL, NULL,
223 	    NULL, NULL,
224 	    0, 0);
225 }
226 
227 int
228 g_io_getattr(const char *attr, struct g_consumer *cp, int *len, void *ptr)
229 {
230 	struct bio *bp;
231 	int error;
232 
233 	g_trace(G_T_BIO, "bio_getattr(%s)", attr);
234 	bp = g_alloc_bio();
235 	bp->bio_cmd = BIO_GETATTR;
236 	bp->bio_done = NULL;
237 	bp->bio_attribute = attr;
238 	bp->bio_length = *len;
239 	bp->bio_data = ptr;
240 	g_io_request(bp, cp);
241 	error = biowait(bp, "ggetattr");
242 	*len = bp->bio_completed;
243 	g_destroy_bio(bp);
244 	return (error);
245 }
246 
247 int
248 g_io_flush(struct g_consumer *cp)
249 {
250 	struct bio *bp;
251 	int error;
252 
253 	g_trace(G_T_BIO, "bio_flush(%s)", cp->provider->name);
254 	bp = g_alloc_bio();
255 	bp->bio_cmd = BIO_FLUSH;
256 	bp->bio_done = NULL;
257 	bp->bio_attribute = NULL;
258 	bp->bio_offset = cp->provider->mediasize;
259 	bp->bio_length = 0;
260 	bp->bio_data = NULL;
261 	g_io_request(bp, cp);
262 	error = biowait(bp, "gflush");
263 	g_destroy_bio(bp);
264 	return (error);
265 }
266 
267 static int
268 g_io_check(struct bio *bp)
269 {
270 	struct g_consumer *cp;
271 	struct g_provider *pp;
272 
273 	cp = bp->bio_from;
274 	pp = bp->bio_to;
275 
276 	/* Fail if access counters dont allow the operation */
277 	switch(bp->bio_cmd) {
278 	case BIO_READ:
279 	case BIO_GETATTR:
280 		if (cp->acr == 0)
281 			return (EPERM);
282 		break;
283 	case BIO_WRITE:
284 	case BIO_DELETE:
285 	case BIO_FLUSH:
286 		if (cp->acw == 0)
287 			return (EPERM);
288 		break;
289 	default:
290 		return (EPERM);
291 	}
292 	/* if provider is marked for error, don't disturb. */
293 	if (pp->error)
294 		return (pp->error);
295 
296 	switch(bp->bio_cmd) {
297 	case BIO_READ:
298 	case BIO_WRITE:
299 	case BIO_DELETE:
300 		/* Zero sectorsize is a probably lack of media */
301 		if (pp->sectorsize == 0)
302 			return (ENXIO);
303 		/* Reject I/O not on sector boundary */
304 		if (bp->bio_offset % pp->sectorsize)
305 			return (EINVAL);
306 		/* Reject I/O not integral sector long */
307 		if (bp->bio_length % pp->sectorsize)
308 			return (EINVAL);
309 		/* Reject requests before or past the end of media. */
310 		if (bp->bio_offset < 0)
311 			return (EIO);
312 		if (bp->bio_offset > pp->mediasize)
313 			return (EIO);
314 		break;
315 	default:
316 		break;
317 	}
318 	return (0);
319 }
320 
321 void
322 g_io_request(struct bio *bp, struct g_consumer *cp)
323 {
324 	struct g_provider *pp;
325 
326 	KASSERT(cp != NULL, ("NULL cp in g_io_request"));
327 	KASSERT(bp != NULL, ("NULL bp in g_io_request"));
328 	pp = cp->provider;
329 	KASSERT(pp != NULL, ("consumer not attached in g_io_request"));
330 #ifdef DIAGNOSTIC
331 	KASSERT(bp->bio_driver1 == NULL,
332 	    ("bio_driver1 used by the consumer (geom %s)", cp->geom->name));
333 	KASSERT(bp->bio_driver2 == NULL,
334 	    ("bio_driver2 used by the consumer (geom %s)", cp->geom->name));
335 	KASSERT(bp->bio_pflags == 0,
336 	    ("bio_pflags used by the consumer (geom %s)", cp->geom->name));
337 	/*
338 	 * Remember consumer's private fields, so we can detect if they were
339 	 * modified by the provider.
340 	 */
341 	bp->_bio_caller1 = bp->bio_caller1;
342 	bp->_bio_caller2 = bp->bio_caller2;
343 	bp->_bio_cflags = bp->bio_cflags;
344 #endif
345 
346 	if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_GETATTR)) {
347 		KASSERT(bp->bio_data != NULL,
348 		    ("NULL bp->data in g_io_request(cmd=%hhu)", bp->bio_cmd));
349 	}
350 	if (bp->bio_cmd & (BIO_DELETE|BIO_FLUSH)) {
351 		KASSERT(bp->bio_data == NULL,
352 		    ("non-NULL bp->data in g_io_request(cmd=%hhu)",
353 		    bp->bio_cmd));
354 	}
355 	if (bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_DELETE)) {
356 		KASSERT(bp->bio_offset % cp->provider->sectorsize == 0,
357 		    ("wrong offset %jd for sectorsize %u",
358 		    bp->bio_offset, cp->provider->sectorsize));
359 		KASSERT(bp->bio_length % cp->provider->sectorsize == 0,
360 		    ("wrong length %jd for sectorsize %u",
361 		    bp->bio_length, cp->provider->sectorsize));
362 	}
363 
364 	g_trace(G_T_BIO, "bio_request(%p) from %p(%s) to %p(%s) cmd %d",
365 	    bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd);
366 
367 	bp->bio_from = cp;
368 	bp->bio_to = pp;
369 	bp->bio_error = 0;
370 	bp->bio_completed = 0;
371 
372 	KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
373 	    ("Bio already on queue bp=%p", bp));
374 	bp->bio_flags |= BIO_ONQUEUE;
375 
376 	binuptime(&bp->bio_t0);
377 
378 	/*
379 	 * The statistics collection is lockless, as such, but we
380 	 * can not update one instance of the statistics from more
381 	 * than one thread at a time, so grab the lock first.
382 	 */
383 	g_bioq_lock(&g_bio_run_down);
384 	if (g_collectstats & 1)
385 		devstat_start_transaction(pp->stat, &bp->bio_t0);
386 	if (g_collectstats & 2)
387 		devstat_start_transaction(cp->stat, &bp->bio_t0);
388 
389 	pp->nstart++;
390 	cp->nstart++;
391 	TAILQ_INSERT_TAIL(&g_bio_run_down.bio_queue, bp, bio_queue);
392 	g_bio_run_down.bio_queue_length++;
393 	g_bioq_unlock(&g_bio_run_down);
394 
395 	/* Pass it on down. */
396 	wakeup(&g_wait_down);
397 }
398 
399 void
400 g_io_deliver(struct bio *bp, int error)
401 {
402 	struct g_consumer *cp;
403 	struct g_provider *pp;
404 
405 	KASSERT(bp != NULL, ("NULL bp in g_io_deliver"));
406 	pp = bp->bio_to;
407 	KASSERT(pp != NULL, ("NULL bio_to in g_io_deliver"));
408 #ifdef DIAGNOSTIC
409 	KASSERT(bp->bio_caller1 == bp->_bio_caller1,
410 	    ("bio_caller1 used by the provider %s", pp->name));
411 	KASSERT(bp->bio_caller2 == bp->_bio_caller2,
412 	    ("bio_caller2 used by the provider %s", pp->name));
413 	KASSERT(bp->bio_cflags == bp->_bio_cflags,
414 	    ("bio_cflags used by the provider %s", pp->name));
415 #endif
416 	cp = bp->bio_from;
417 	if (cp == NULL) {
418 		bp->bio_error = error;
419 		bp->bio_done(bp);
420 		return;
421 	}
422 	KASSERT(cp != NULL, ("NULL bio_from in g_io_deliver"));
423 	KASSERT(cp->geom != NULL, ("NULL bio_from->geom in g_io_deliver"));
424 	KASSERT(bp->bio_completed >= 0, ("bio_completed can't be less than 0"));
425 	KASSERT(bp->bio_completed <= bp->bio_length,
426 	    ("bio_completed can't be greater than bio_length"));
427 
428 	g_trace(G_T_BIO,
429 "g_io_deliver(%p) from %p(%s) to %p(%s) cmd %d error %d off %jd len %jd",
430 	    bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd, error,
431 	    (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
432 
433 	KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
434 	    ("Bio already on queue bp=%p", bp));
435 
436 	/*
437 	 * XXX: next two doesn't belong here
438 	 */
439 	bp->bio_bcount = bp->bio_length;
440 	bp->bio_resid = bp->bio_bcount - bp->bio_completed;
441 
442 	/*
443 	 * The statistics collection is lockless, as such, but we
444 	 * can not update one instance of the statistics from more
445 	 * than one thread at a time, so grab the lock first.
446 	 */
447 	g_bioq_lock(&g_bio_run_up);
448 	if (g_collectstats & 1)
449 		devstat_end_transaction_bio(pp->stat, bp);
450 	if (g_collectstats & 2)
451 		devstat_end_transaction_bio(cp->stat, bp);
452 
453 	cp->nend++;
454 	pp->nend++;
455 	if (error != ENOMEM) {
456 		bp->bio_error = error;
457 		TAILQ_INSERT_TAIL(&g_bio_run_up.bio_queue, bp, bio_queue);
458 		bp->bio_flags |= BIO_ONQUEUE;
459 		g_bio_run_up.bio_queue_length++;
460 		g_bioq_unlock(&g_bio_run_up);
461 		wakeup(&g_wait_up);
462 		return;
463 	}
464 	g_bioq_unlock(&g_bio_run_up);
465 
466 	if (bootverbose)
467 		printf("ENOMEM %p on %p(%s)\n", bp, pp, pp->name);
468 	bp->bio_children = 0;
469 	bp->bio_inbed = 0;
470 	g_io_request(bp, cp);
471 	pace++;
472 	return;
473 }
474 
475 void
476 g_io_schedule_down(struct thread *tp __unused)
477 {
478 	struct bio *bp;
479 	off_t excess;
480 	int error;
481 
482 	for(;;) {
483 		g_bioq_lock(&g_bio_run_down);
484 		bp = g_bioq_first(&g_bio_run_down);
485 		if (bp == NULL) {
486 			CTR0(KTR_GEOM, "g_down going to sleep");
487 			msleep(&g_wait_down, &g_bio_run_down.bio_queue_lock,
488 			    PRIBIO | PDROP, "-", hz/10);
489 			continue;
490 		}
491 		CTR0(KTR_GEOM, "g_down has work to do");
492 		g_bioq_unlock(&g_bio_run_down);
493 		if (pace > 0) {
494 			CTR1(KTR_GEOM, "g_down pacing self (pace %d)", pace);
495 			pause("g_down", hz/10);
496 			pace--;
497 		}
498 		error = g_io_check(bp);
499 		if (error) {
500 			CTR3(KTR_GEOM, "g_down g_io_check on bp %p provider "
501 			    "%s returned %d", bp, bp->bio_to->name, error);
502 			g_io_deliver(bp, error);
503 			continue;
504 		}
505 		CTR2(KTR_GEOM, "g_down processing bp %p provider %s", bp,
506 		    bp->bio_to->name);
507 		switch (bp->bio_cmd) {
508 		case BIO_READ:
509 		case BIO_WRITE:
510 		case BIO_DELETE:
511 			/* Truncate requests to the end of providers media. */
512 			/*
513 			 * XXX: What if we truncate because of offset being
514 			 * bad, not length?
515 			 */
516 			excess = bp->bio_offset + bp->bio_length;
517 			if (excess > bp->bio_to->mediasize) {
518 				excess -= bp->bio_to->mediasize;
519 				bp->bio_length -= excess;
520 				if (excess > 0)
521 					CTR3(KTR_GEOM, "g_down truncated bio "
522 					    "%p provider %s by %d", bp,
523 					    bp->bio_to->name, excess);
524 			}
525 			/* Deliver zero length transfers right here. */
526 			if (bp->bio_length == 0) {
527 				g_io_deliver(bp, 0);
528 				CTR2(KTR_GEOM, "g_down terminated 0-length "
529 				    "bp %p provider %s", bp, bp->bio_to->name);
530 				continue;
531 			}
532 			break;
533 		default:
534 			break;
535 		}
536 		THREAD_NO_SLEEPING();
537 		CTR4(KTR_GEOM, "g_down starting bp %p provider %s off %ld "
538 		    "len %ld", bp, bp->bio_to->name, bp->bio_offset,
539 		    bp->bio_length);
540 		bp->bio_to->geom->start(bp);
541 		THREAD_SLEEPING_OK();
542 	}
543 }
544 
545 void
546 bio_taskqueue(struct bio *bp, bio_task_t *func, void *arg)
547 {
548 	bp->bio_task = func;
549 	bp->bio_task_arg = arg;
550 	/*
551 	 * The taskqueue is actually just a second queue off the "up"
552 	 * queue, so we use the same lock.
553 	 */
554 	g_bioq_lock(&g_bio_run_up);
555 	KASSERT(!(bp->bio_flags & BIO_ONQUEUE),
556 	    ("Bio already on queue bp=%p target taskq", bp));
557 	bp->bio_flags |= BIO_ONQUEUE;
558 	TAILQ_INSERT_TAIL(&g_bio_run_task.bio_queue, bp, bio_queue);
559 	g_bio_run_task.bio_queue_length++;
560 	wakeup(&g_wait_up);
561 	g_bioq_unlock(&g_bio_run_up);
562 }
563 
564 
565 void
566 g_io_schedule_up(struct thread *tp __unused)
567 {
568 	struct bio *bp;
569 	for(;;) {
570 		g_bioq_lock(&g_bio_run_up);
571 		bp = g_bioq_first(&g_bio_run_task);
572 		if (bp != NULL) {
573 			g_bioq_unlock(&g_bio_run_up);
574 			THREAD_NO_SLEEPING();
575 			CTR1(KTR_GEOM, "g_up processing task bp %p", bp);
576 			bp->bio_task(bp->bio_task_arg);
577 			THREAD_SLEEPING_OK();
578 			continue;
579 		}
580 		bp = g_bioq_first(&g_bio_run_up);
581 		if (bp != NULL) {
582 			g_bioq_unlock(&g_bio_run_up);
583 			THREAD_NO_SLEEPING();
584 			CTR4(KTR_GEOM, "g_up biodone bp %p provider %s off "
585 			    "%ld len %ld", bp, bp->bio_to->name,
586 			    bp->bio_offset, bp->bio_length);
587 			biodone(bp);
588 			THREAD_SLEEPING_OK();
589 			continue;
590 		}
591 		CTR0(KTR_GEOM, "g_up going to sleep");
592 		msleep(&g_wait_up, &g_bio_run_up.bio_queue_lock,
593 		    PRIBIO | PDROP, "-", hz/10);
594 	}
595 }
596 
597 void *
598 g_read_data(struct g_consumer *cp, off_t offset, off_t length, int *error)
599 {
600 	struct bio *bp;
601 	void *ptr;
602 	int errorc;
603 
604 	KASSERT(length > 0 && length >= cp->provider->sectorsize &&
605 	    length <= MAXPHYS, ("g_read_data(): invalid length %jd",
606 	    (intmax_t)length));
607 
608 	bp = g_alloc_bio();
609 	bp->bio_cmd = BIO_READ;
610 	bp->bio_done = NULL;
611 	bp->bio_offset = offset;
612 	bp->bio_length = length;
613 	ptr = g_malloc(length, M_WAITOK);
614 	bp->bio_data = ptr;
615 	g_io_request(bp, cp);
616 	errorc = biowait(bp, "gread");
617 	if (error != NULL)
618 		*error = errorc;
619 	g_destroy_bio(bp);
620 	if (errorc) {
621 		g_free(ptr);
622 		ptr = NULL;
623 	}
624 	return (ptr);
625 }
626 
627 int
628 g_write_data(struct g_consumer *cp, off_t offset, void *ptr, off_t length)
629 {
630 	struct bio *bp;
631 	int error;
632 
633 	KASSERT(length > 0 && length >= cp->provider->sectorsize &&
634 	    length <= MAXPHYS, ("g_write_data(): invalid length %jd",
635 	    (intmax_t)length));
636 
637 	bp = g_alloc_bio();
638 	bp->bio_cmd = BIO_WRITE;
639 	bp->bio_done = NULL;
640 	bp->bio_offset = offset;
641 	bp->bio_length = length;
642 	bp->bio_data = ptr;
643 	g_io_request(bp, cp);
644 	error = biowait(bp, "gwrite");
645 	g_destroy_bio(bp);
646 	return (error);
647 }
648 
649 void
650 g_print_bio(struct bio *bp)
651 {
652 	const char *pname, *cmd = NULL;
653 
654 	if (bp->bio_to != NULL)
655 		pname = bp->bio_to->name;
656 	else
657 		pname = "[unknown]";
658 
659 	switch (bp->bio_cmd) {
660 	case BIO_GETATTR:
661 		cmd = "GETATTR";
662 		printf("%s[%s(attr=%s)]", pname, cmd, bp->bio_attribute);
663 		return;
664 	case BIO_FLUSH:
665 		cmd = "FLUSH";
666 		printf("%s[%s]", pname, cmd);
667 		return;
668 	case BIO_READ:
669 		cmd = "READ";
670 	case BIO_WRITE:
671 		if (cmd == NULL)
672 			cmd = "WRITE";
673 	case BIO_DELETE:
674 		if (cmd == NULL)
675 			cmd = "DELETE";
676 		printf("%s[%s(offset=%jd, length=%jd)]", pname, cmd,
677 		    (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
678 		return;
679 	default:
680 		cmd = "UNKNOWN";
681 		printf("%s[%s()]", pname, cmd);
682 		return;
683 	}
684 	/* NOTREACHED */
685 }
686