geom_io.c revision 114508 
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 * $FreeBSD: head/sys/geom/geom_io.c 114508 2003-05-02 06:36:14Z phk $
36 */
37
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
45#include <sys/errno.h>
46#include <geom/geom.h>
47#include <geom/geom_int.h>
48#include <sys/devicestat.h>
49
50static struct g_bioq g_bio_run_down;
51static struct g_bioq g_bio_run_up;
52static struct g_bioq g_bio_idle;
53
54static u_int pace;
55
56#include <machine/atomic.h>
57
58static void
59g_bioq_lock(struct g_bioq *bq)
60{
61
62	mtx_lock(&bq->bio_queue_lock);
63}
64
65static void
66g_bioq_unlock(struct g_bioq *bq)
67{
68
69	mtx_unlock(&bq->bio_queue_lock);
70}
71
72#if 0
73static void
74g_bioq_destroy(struct g_bioq *bq)
75{
76
77	mtx_destroy(&bq->bio_queue_lock);
78}
79#endif
80
81static void
82g_bioq_init(struct g_bioq *bq)
83{
84
85	TAILQ_INIT(&bq->bio_queue);
86	mtx_init(&bq->bio_queue_lock, "bio queue", NULL, MTX_DEF);
87}
88
89static struct bio *
90g_bioq_first(struct g_bioq *bq)
91{
92	struct bio *bp;
93
94	bp = TAILQ_FIRST(&bq->bio_queue);
95	if (bp != NULL) {
96		TAILQ_REMOVE(&bq->bio_queue, bp, bio_queue);
97		bq->bio_queue_length--;
98	}
99	return (bp);
100}
101
102static void
103g_bioq_enqueue_tail(struct bio *bp, struct g_bioq *rq)
104{
105
106	g_bioq_lock(rq);
107	TAILQ_INSERT_TAIL(&rq->bio_queue, bp, bio_queue);
108	rq->bio_queue_length++;
109	g_bioq_unlock(rq);
110}
111
112MALLOC_DEFINE(M_GEOMBIO, "GEOM bio", "Geom bio");
113
114struct bio *
115g_new_bio(void)
116{
117	struct bio *bp;
118
119	g_bioq_lock(&g_bio_idle);
120	bp = g_bioq_first(&g_bio_idle);
121	g_bioq_unlock(&g_bio_idle);
122	if (bp == NULL)
123		bp = malloc(sizeof *bp, M_GEOMBIO, M_NOWAIT | M_ZERO);
124	/* g_trace(G_T_BIO, "g_new_bio() = %p", bp); */
125	return (bp);
126}
127
128void
129g_destroy_bio(struct bio *bp)
130{
131
132#if 0
133	/* g_trace(G_T_BIO, "g_destroy_bio(%p)", bp); */
134	bzero(bp, sizeof *bp);
135	g_bioq_enqueue_tail(bp, &g_bio_idle);
136#else
137	free(bp, M_GEOMBIO);
138#endif
139}
140
141struct bio *
142g_clone_bio(struct bio *bp)
143{
144	struct bio *bp2;
145
146	bp2 = g_new_bio();
147	if (bp2 != NULL) {
148		bp2->bio_parent = bp;
149		bp2->bio_cmd = bp->bio_cmd;
150		bp2->bio_length = bp->bio_length;
151		bp2->bio_offset = bp->bio_offset;
152		bp2->bio_data = bp->bio_data;
153		bp2->bio_attribute = bp->bio_attribute;
154		bp->bio_children++;
155	}
156	/* g_trace(G_T_BIO, "g_clone_bio(%p) = %p", bp, bp2); */
157	return(bp2);
158}
159
160void
161g_io_init()
162{
163
164	g_bioq_init(&g_bio_run_down);
165	g_bioq_init(&g_bio_run_up);
166	g_bioq_init(&g_bio_idle);
167}
168
169int
170g_io_getattr(const char *attr, struct g_consumer *cp, int *len, void *ptr)
171{
172	struct bio *bp;
173	int error;
174
175	g_trace(G_T_BIO, "bio_getattr(%s)", attr);
176	bp = g_new_bio();
177	bp->bio_cmd = BIO_GETATTR;
178	bp->bio_done = NULL;
179	bp->bio_attribute = attr;
180	bp->bio_length = *len;
181	bp->bio_data = ptr;
182	g_io_request(bp, cp);
183	error = biowait(bp, "ggetattr");
184	*len = bp->bio_completed;
185	g_destroy_bio(bp);
186	return (error);
187}
188
189static int
190g_io_check(struct bio *bp)
191{
192	struct g_consumer *cp;
193	struct g_provider *pp;
194
195	cp = bp->bio_from;
196	pp = bp->bio_to;
197
198	/* Fail if access counters dont allow the operation */
199	switch(bp->bio_cmd) {
200	case BIO_READ:
201	case BIO_GETATTR:
202		if (cp->acr == 0)
203			return (EPERM);
204		break;
205	case BIO_WRITE:
206	case BIO_DELETE:
207		if (cp->acw == 0)
208			return (EPERM);
209		break;
210	default:
211		return (EPERM);
212	}
213	/* if provider is marked for error, don't disturb. */
214	if (pp->error)
215		return (pp->error);
216
217	switch(bp->bio_cmd) {
218	case BIO_READ:
219	case BIO_WRITE:
220	case BIO_DELETE:
221		/* Reject I/O not on sector boundary */
222		if (bp->bio_offset % pp->sectorsize)
223			return (EINVAL);
224		/* Reject I/O not integral sector long */
225		if (bp->bio_length % pp->sectorsize)
226			return (EINVAL);
227		/* Reject requests past the end of media. */
228		if (bp->bio_offset > pp->mediasize)
229			return (EIO);
230		break;
231	default:
232		break;
233	}
234	return (0);
235}
236
237void
238g_io_request(struct bio *bp, struct g_consumer *cp)
239{
240	struct g_provider *pp;
241
242	pp = cp->provider;
243	KASSERT(cp != NULL, ("NULL cp in g_io_request"));
244	KASSERT(bp != NULL, ("NULL bp in g_io_request"));
245	KASSERT(bp->bio_data != NULL, ("NULL bp->data in g_io_request"));
246	KASSERT(pp != NULL, ("consumer not attached in g_io_request"));
247
248	bp->bio_from = cp;
249	bp->bio_to = pp;
250	bp->bio_error = 0;
251	bp->bio_completed = 0;
252
253	if (g_collectstats) {
254		devstat_start_transaction_bio(cp->stat, bp);
255		devstat_start_transaction_bio(pp->stat, bp);
256	}
257	cp->nstart++;
258	pp->nstart++;
259
260	/* Pass it on down. */
261	g_trace(G_T_BIO, "bio_request(%p) from %p(%s) to %p(%s) cmd %d",
262	    bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd);
263	g_bioq_enqueue_tail(bp, &g_bio_run_down);
264	wakeup(&g_wait_down);
265}
266
267void
268g_io_deliver(struct bio *bp, int error)
269{
270	struct g_consumer *cp;
271	struct g_provider *pp;
272
273	cp = bp->bio_from;
274	pp = bp->bio_to;
275	KASSERT(bp != NULL, ("NULL bp in g_io_deliver"));
276	KASSERT(cp != NULL, ("NULL bio_from in g_io_deliver"));
277	KASSERT(cp->geom != NULL, ("NULL bio_from->geom in g_io_deliver"));
278	KASSERT(pp != NULL, ("NULL bio_to in g_io_deliver"));
279
280	g_trace(G_T_BIO,
281"g_io_deliver(%p) from %p(%s) to %p(%s) cmd %d error %d off %jd len %jd",
282	    bp, cp, cp->geom->name, pp, pp->name, bp->bio_cmd, error,
283	    (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length);
284
285	bp->bio_bcount = bp->bio_length;
286	if (g_collectstats) {
287		bp->bio_resid = bp->bio_bcount - bp->bio_completed;
288		devstat_end_transaction_bio(cp->stat, bp);
289		devstat_end_transaction_bio(pp->stat, bp);
290	}
291	cp->nend++;
292	pp->nend++;
293
294	if (error == ENOMEM) {
295		printf("ENOMEM %p on %p(%s)\n", bp, pp, pp->name);
296		g_io_request(bp, cp);
297		pace++;
298		return;
299	}
300	bp->bio_error = error;
301	g_bioq_enqueue_tail(bp, &g_bio_run_up);
302	wakeup(&g_wait_up);
303}
304
305void
306g_io_schedule_down(struct thread *tp __unused)
307{
308	struct bio *bp;
309	off_t excess;
310	int error;
311	struct mtx mymutex;
312
313	bzero(&mymutex, sizeof mymutex);
314	mtx_init(&mymutex, "g_xdown", MTX_DEF, 0);
315
316	for(;;) {
317		g_bioq_lock(&g_bio_run_down);
318		bp = g_bioq_first(&g_bio_run_down);
319		if (bp == NULL) {
320			msleep(&g_wait_down, &g_bio_run_down.bio_queue_lock,
321			    PRIBIO | PDROP, "g_down", hz/10);
322			continue;
323		}
324		g_bioq_unlock(&g_bio_run_down);
325		if (pace > 0) {
326			msleep(&error, NULL, PRIBIO, "g_down", hz/10);
327			pace--;
328		}
329		error = g_io_check(bp);
330		if (error) {
331			g_io_deliver(bp, error);
332			continue;
333		}
334		switch (bp->bio_cmd) {
335		case BIO_READ:
336		case BIO_WRITE:
337		case BIO_DELETE:
338			/* Truncate requests to the end of providers media. */
339			excess = bp->bio_offset + bp->bio_length;
340			if (excess > bp->bio_to->mediasize) {
341				excess -= bp->bio_to->mediasize;
342				bp->bio_length -= excess;
343			}
344			/* Deliver zero length transfers right here. */
345			if (bp->bio_length == 0) {
346				g_io_deliver(bp, 0);
347				continue;
348			}
349			break;
350		default:
351			break;
352		}
353		mtx_lock(&mymutex);
354		bp->bio_to->geom->start(bp);
355		mtx_unlock(&mymutex);
356	}
357}
358
359void
360g_io_schedule_up(struct thread *tp __unused)
361{
362	struct bio *bp;
363	struct mtx mymutex;
364
365	bzero(&mymutex, sizeof mymutex);
366	mtx_init(&mymutex, "g_xup", MTX_DEF, 0);
367	for(;;) {
368		g_bioq_lock(&g_bio_run_up);
369		bp = g_bioq_first(&g_bio_run_up);
370		if (bp != NULL) {
371			g_bioq_unlock(&g_bio_run_up);
372			mtx_lock(&mymutex);
373			biodone(bp);
374			mtx_unlock(&mymutex);
375			continue;
376		}
377		msleep(&g_wait_up, &g_bio_run_up.bio_queue_lock,
378		    PRIBIO | PDROP, "g_up", hz/10);
379	}
380}
381
382void *
383g_read_data(struct g_consumer *cp, off_t offset, off_t length, int *error)
384{
385	struct bio *bp;
386	void *ptr;
387	int errorc;
388
389	bp = g_new_bio();
390	bp->bio_cmd = BIO_READ;
391	bp->bio_done = NULL;
392	bp->bio_offset = offset;
393	bp->bio_length = length;
394	ptr = g_malloc(length, M_WAITOK);
395	bp->bio_data = ptr;
396	g_io_request(bp, cp);
397	errorc = biowait(bp, "gread");
398	if (error != NULL)
399		*error = errorc;
400	g_destroy_bio(bp);
401	if (errorc) {
402		g_free(ptr);
403		ptr = NULL;
404	}
405	return (ptr);
406}
407
408int
409g_write_data(struct g_consumer *cp, off_t offset, void *ptr, off_t length)
410{
411	struct bio *bp;
412	int error;
413
414	bp = g_new_bio();
415	bp->bio_cmd = BIO_WRITE;
416	bp->bio_done = NULL;
417	bp->bio_offset = offset;
418	bp->bio_length = length;
419	bp->bio_data = ptr;
420	g_io_request(bp, cp);
421	error = biowait(bp, "gwrite");
422	g_destroy_bio(bp);
423	return (error);
424}
425