geom_io.c revision 104058 
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 104058 2002-09-27 20:53:47Z phk $
36 */
37
38
39#include <sys/param.h>
40#ifndef _KERNEL
41#include <stdio.h>
42#include <string.h>
43#include <stdlib.h>
44#include <signal.h>
45#include <err.h>
46#include <sched.h>
47#else
48#include <sys/systm.h>
49#include <sys/kernel.h>
50#include <sys/malloc.h>
51#include <sys/bio.h>
52#endif
53
54#include <sys/errno.h>
55#include <geom/geom.h>
56#include <geom/geom_int.h>
57
58static struct g_bioq g_bio_run_down;
59static struct g_bioq g_bio_run_up;
60static struct g_bioq g_bio_idle;
61
62#include <machine/atomic.h>
63
64static void
65g_bioq_lock(struct g_bioq *bq)
66{
67
68	mtx_lock(&bq->bio_queue_lock);
69}
70
71static void
72g_bioq_unlock(struct g_bioq *bq)
73{
74
75	mtx_unlock(&bq->bio_queue_lock);
76}
77
78#if 0
79static void
80g_bioq_destroy(struct g_bioq *bq)
81{
82
83	mtx_destroy(&bq->bio_queue_lock);
84}
85#endif
86
87static void
88g_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
95static struct bio *
96g_bioq_first(struct g_bioq *bq)
97{
98	struct bio *bp;
99
100	g_bioq_lock(bq);
101	bp = TAILQ_FIRST(&bq->bio_queue);
102	if (bp != NULL) {
103		TAILQ_REMOVE(&bq->bio_queue, bp, bio_queue);
104		bq->bio_queue_length--;
105	}
106	g_bioq_unlock(bq);
107	return (bp);
108}
109
110static void
111g_bioq_enqueue_tail(struct bio *bp, struct g_bioq *rq)
112{
113
114	g_bioq_lock(rq);
115	TAILQ_INSERT_TAIL(&rq->bio_queue, bp, bio_queue);
116	rq->bio_queue_length++;
117	g_bioq_unlock(rq);
118}
119
120struct bio *
121g_new_bio(void)
122{
123	struct bio *bp;
124
125	bp = g_bioq_first(&g_bio_idle);
126	if (bp == NULL)
127		bp = g_malloc(sizeof *bp, M_NOWAIT | M_ZERO);
128	g_trace(G_T_BIO, "g_new_bio() = %p", bp);
129	return (bp);
130}
131
132void
133g_destroy_bio(struct bio *bp)
134{
135
136	g_trace(G_T_BIO, "g_destroy_bio(%p)", bp);
137	bzero(bp, sizeof *bp);
138	g_bioq_enqueue_tail(bp, &g_bio_idle);
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_linkage = 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	}
155	g_trace(G_T_BIO, "g_clone_bio(%p) = %p", bp, bp2);
156	return(bp2);
157}
158
159void
160g_io_init()
161{
162
163	g_bioq_init(&g_bio_run_down);
164	g_bioq_init(&g_bio_run_up);
165	g_bioq_init(&g_bio_idle);
166}
167
168int
169g_io_setattr(const char *attr, struct g_consumer *cp, int len, void *ptr)
170{
171	struct bio *bp;
172	int error;
173
174	g_trace(G_T_BIO, "bio_setattr(%s)", attr);
175	do {
176		bp = g_new_bio();
177		bp->bio_cmd = BIO_SETATTR;
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, "gsetattr");
184		g_destroy_bio(bp);
185		if (error == EBUSY)
186			tsleep(&error, 0, "setattr_busy", hz);
187	} while(error == EBUSY);
188	return (error);
189}
190
191
192int
193g_io_getattr(const char *attr, struct g_consumer *cp, int *len, void *ptr)
194{
195	struct bio *bp;
196	int error;
197
198	g_trace(G_T_BIO, "bio_getattr(%s)", attr);
199	do {
200		bp = g_new_bio();
201		bp->bio_cmd = BIO_GETATTR;
202		bp->bio_done = NULL;
203		bp->bio_attribute = attr;
204		bp->bio_length = *len;
205		bp->bio_data = ptr;
206		g_io_request(bp, cp);
207		error = biowait(bp, "ggetattr");
208		*len = bp->bio_completed;
209		g_destroy_bio(bp);
210		if (error == EBUSY)
211			tsleep(&error, 0, "getattr_busy", hz);
212
213	} while(error == EBUSY);
214	return (error);
215}
216
217void
218g_io_fail(struct bio *bp, int error)
219{
220
221	bp->bio_error = error;
222
223	g_trace(G_T_BIO,
224	    "bio_fail(%p) from %p(%s) to %p(%s) cmd %d error %d\n",
225	    bp, bp->bio_from, bp->bio_from->geom->name,
226	    bp->bio_to, bp->bio_to->name, bp->bio_cmd, bp->bio_error);
227	g_io_deliver(bp);
228	return;
229}
230
231void
232g_io_request(struct bio *bp, struct g_consumer *cp)
233{
234	int error;
235	off_t excess;
236
237	KASSERT(cp != NULL, ("bio_request on thin air"));
238	error = 0;
239	bp->bio_from = cp;
240	bp->bio_to = cp->provider;
241	bp->bio_error = 0;
242	bp->bio_completed = 0;
243
244	/* begin_stats(&bp->stats); */
245
246	atomic_add_int(&cp->biocount, 1);
247	/* Fail on unattached consumers */
248	if (bp->bio_to == NULL)
249		return (g_io_fail(bp, ENXIO));
250	/* Fail if access doesn't allow operation */
251	switch(bp->bio_cmd) {
252	case BIO_READ:
253	case BIO_GETATTR:
254		if (cp->acr == 0)
255			return (g_io_fail(bp, EPERM));
256		break;
257	case BIO_WRITE:
258	case BIO_DELETE:
259		if (cp->acw == 0)
260			return (g_io_fail(bp, EPERM));
261		break;
262	case BIO_SETATTR:
263		if ((cp->acw == 0) || (cp->ace == 0))
264			return (g_io_fail(bp, EPERM));
265		break;
266	default:
267		return (g_io_fail(bp, EPERM));
268	}
269	/* if provider is marked for error, don't disturb. */
270	if (bp->bio_to->error)
271		return (g_io_fail(bp, bp->bio_to->error));
272	switch(bp->bio_cmd) {
273	case BIO_READ:
274	case BIO_WRITE:
275	case BIO_DELETE:
276		/* Reject requests past the end of media. */
277		if (bp->bio_offset > bp->bio_to->mediasize)
278			return (g_io_fail(bp, EIO));
279		/* Truncate requests to the end of providers media. */
280		excess = bp->bio_offset + bp->bio_length;
281		if (excess > bp->bio_to->mediasize) {
282			excess -= bp->bio_to->mediasize;
283			bp->bio_length -= excess;
284		}
285		/* Deliver zero length transfers right here. */
286		if (bp->bio_length == 0)
287			return (g_io_deliver(bp));
288		break;
289	default:
290		break;
291	}
292	/* Pass it on down. */
293	g_trace(G_T_BIO, "bio_request(%p) from %p(%s) to %p(%s) cmd %d",
294	    bp, bp->bio_from, bp->bio_from->geom->name,
295	    bp->bio_to, bp->bio_to->name, bp->bio_cmd);
296	g_bioq_enqueue_tail(bp, &g_bio_run_down);
297	wakeup(&g_wait_down);
298}
299
300void
301g_io_deliver(struct bio *bp)
302{
303
304	g_trace(G_T_BIO,
305	    "g_io_deliver(%p) from %p(%s) to %p(%s) cmd %d error %d",
306	    bp, bp->bio_from, bp->bio_from->geom->name,
307	    bp->bio_to, bp->bio_to->name, bp->bio_cmd, bp->bio_error);
308	/* finish_stats(&bp->stats); */
309
310	g_bioq_enqueue_tail(bp, &g_bio_run_up);
311
312	wakeup(&g_wait_up);
313}
314
315void
316g_io_schedule_down(struct thread *tp __unused)
317{
318	struct bio *bp;
319
320	for(;;) {
321		bp = g_bioq_first(&g_bio_run_down);
322		if (bp == NULL)
323			break;
324		bp->bio_to->geom->start(bp);
325	}
326}
327
328void
329g_io_schedule_up(struct thread *tp __unused)
330{
331	struct bio *bp;
332	struct g_consumer *cp;
333
334	for(;;) {
335		bp = g_bioq_first(&g_bio_run_up);
336		if (bp == NULL)
337			break;
338
339		cp = bp->bio_from;
340
341		atomic_add_int(&cp->biocount, -1);
342		biodone(bp);
343	}
344}
345
346void *
347g_read_data(struct g_consumer *cp, off_t offset, off_t length, int *error)
348{
349	struct bio *bp;
350	void *ptr;
351	int errorc;
352
353        do {
354		bp = g_new_bio();
355		bp->bio_cmd = BIO_READ;
356		bp->bio_done = NULL;
357		bp->bio_offset = offset;
358		bp->bio_length = length;
359		ptr = g_malloc(length, M_WAITOK);
360		bp->bio_data = ptr;
361		g_io_request(bp, cp);
362		errorc = biowait(bp, "gread");
363		if (error != NULL)
364			*error = errorc;
365		g_destroy_bio(bp);
366		if (errorc) {
367			g_free(ptr);
368			ptr = NULL;
369		}
370		if (errorc == EBUSY)
371			tsleep(&errorc, 0, "g_read_data_busy", hz);
372        } while (errorc == EBUSY);
373	return (ptr);
374}
375