geom_io.c revision 104194 
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 104194 2002-09-30 08:50:47Z 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	bp = g_new_bio();
176	bp->bio_cmd = BIO_SETATTR;
177	bp->bio_done = NULL;
178	bp->bio_attribute = attr;
179	bp->bio_length = len;
180	bp->bio_data = ptr;
181	g_io_request(bp, cp);
182	error = biowait(bp, "gsetattr");
183	g_destroy_bio(bp);
184	return (error);
185}
186
187
188int
189g_io_getattr(const char *attr, struct g_consumer *cp, int *len, void *ptr)
190{
191	struct bio *bp;
192	int error;
193
194	g_trace(G_T_BIO, "bio_getattr(%s)", attr);
195	do {
196		bp = g_new_bio();
197		bp->bio_cmd = BIO_GETATTR;
198		bp->bio_done = NULL;
199		bp->bio_attribute = attr;
200		bp->bio_length = *len;
201		bp->bio_data = ptr;
202		g_io_request(bp, cp);
203		error = biowait(bp, "ggetattr");
204		*len = bp->bio_completed;
205		g_destroy_bio(bp);
206		if (error == EBUSY)
207			tsleep(&error, 0, "getattr_busy", hz);
208
209	} while(error == EBUSY);
210	return (error);
211}
212
213void
214g_io_fail(struct bio *bp, int error)
215{
216
217	bp->bio_error = error;
218
219	g_trace(G_T_BIO,
220	    "bio_fail(%p) from %p(%s) to %p(%s) cmd %d error %d\n",
221	    bp, bp->bio_from, bp->bio_from->geom->name,
222	    bp->bio_to, bp->bio_to->name, bp->bio_cmd, bp->bio_error);
223	g_io_deliver(bp);
224	return;
225}
226
227void
228g_io_request(struct bio *bp, struct g_consumer *cp)
229{
230	int error;
231	off_t excess;
232
233	KASSERT(cp != NULL, ("bio_request on thin air"));
234	error = 0;
235	bp->bio_from = cp;
236	bp->bio_to = cp->provider;
237	bp->bio_error = 0;
238	bp->bio_completed = 0;
239
240	/* begin_stats(&bp->stats); */
241
242	atomic_add_int(&cp->biocount, 1);
243	/* Fail on unattached consumers */
244	if (bp->bio_to == NULL) {
245		g_io_fail(bp, ENXIO);
246		return;
247	}
248	/* Fail if access doesn't allow operation */
249	switch(bp->bio_cmd) {
250	case BIO_READ:
251	case BIO_GETATTR:
252		if (cp->acr == 0) {
253			g_io_fail(bp, EPERM);
254			return;
255		}
256		break;
257	case BIO_WRITE:
258	case BIO_DELETE:
259		if (cp->acw == 0) {
260			g_io_fail(bp, EPERM);
261			return;
262		}
263		break;
264	case BIO_SETATTR:
265		/* XXX: Should ideally check for (cp->ace == 0) */
266		if ((cp->acw == 0)) {
267			printf("setattr on %s mode (%d,%d,%d)\n",
268				cp->provider->name,
269				cp->acr, cp->acw, cp->ace);
270			g_io_fail(bp, EPERM);
271			return;
272		}
273		break;
274	default:
275		g_io_fail(bp, EPERM);
276		return;
277	}
278	/* if provider is marked for error, don't disturb. */
279	if (bp->bio_to->error) {
280		g_io_fail(bp, bp->bio_to->error);
281		return;
282	}
283	switch(bp->bio_cmd) {
284	case BIO_READ:
285	case BIO_WRITE:
286	case BIO_DELETE:
287		/* Reject requests past the end of media. */
288		if (bp->bio_offset > bp->bio_to->mediasize) {
289			g_io_fail(bp, EIO);
290			return;
291		}
292		/* Truncate requests to the end of providers media. */
293		excess = bp->bio_offset + bp->bio_length;
294		if (excess > bp->bio_to->mediasize) {
295			excess -= bp->bio_to->mediasize;
296			bp->bio_length -= excess;
297		}
298		/* Deliver zero length transfers right here. */
299		if (bp->bio_length == 0) {
300			g_io_deliver(bp);
301			return;
302		}
303		break;
304	default:
305		break;
306	}
307	/* Pass it on down. */
308	g_trace(G_T_BIO, "bio_request(%p) from %p(%s) to %p(%s) cmd %d",
309	    bp, bp->bio_from, bp->bio_from->geom->name,
310	    bp->bio_to, bp->bio_to->name, bp->bio_cmd);
311	g_bioq_enqueue_tail(bp, &g_bio_run_down);
312	wakeup(&g_wait_down);
313}
314
315void
316g_io_deliver(struct bio *bp)
317{
318
319	g_trace(G_T_BIO,
320	    "g_io_deliver(%p) from %p(%s) to %p(%s) cmd %d error %d",
321	    bp, bp->bio_from, bp->bio_from->geom->name,
322	    bp->bio_to, bp->bio_to->name, bp->bio_cmd, bp->bio_error);
323	/* finish_stats(&bp->stats); */
324
325	g_bioq_enqueue_tail(bp, &g_bio_run_up);
326
327	wakeup(&g_wait_up);
328}
329
330void
331g_io_schedule_down(struct thread *tp __unused)
332{
333	struct bio *bp;
334
335	for(;;) {
336		bp = g_bioq_first(&g_bio_run_down);
337		if (bp == NULL)
338			break;
339		bp->bio_to->geom->start(bp);
340	}
341}
342
343void
344g_io_schedule_up(struct thread *tp __unused)
345{
346	struct bio *bp;
347	struct g_consumer *cp;
348
349	for(;;) {
350		bp = g_bioq_first(&g_bio_run_up);
351		if (bp == NULL)
352			break;
353
354		cp = bp->bio_from;
355
356		atomic_add_int(&cp->biocount, -1);
357		biodone(bp);
358	}
359}
360
361void *
362g_read_data(struct g_consumer *cp, off_t offset, off_t length, int *error)
363{
364	struct bio *bp;
365	void *ptr;
366	int errorc;
367
368        do {
369		bp = g_new_bio();
370		bp->bio_cmd = BIO_READ;
371		bp->bio_done = NULL;
372		bp->bio_offset = offset;
373		bp->bio_length = length;
374		ptr = g_malloc(length, M_WAITOK);
375		bp->bio_data = ptr;
376		g_io_request(bp, cp);
377		errorc = biowait(bp, "gread");
378		if (error != NULL)
379			*error = errorc;
380		g_destroy_bio(bp);
381		if (errorc) {
382			g_free(ptr);
383			ptr = NULL;
384		}
385		if (errorc == EBUSY)
386			tsleep(&errorc, 0, "g_read_data_busy", hz);
387        } while (errorc == EBUSY);
388	return (ptr);
389}
390
391int
392g_write_data(struct g_consumer *cp, off_t offset, void *ptr, off_t length)
393{
394	struct bio *bp;
395	int error;
396
397	bp = g_new_bio();
398	bp->bio_cmd = BIO_WRITE;
399	bp->bio_done = NULL;
400	bp->bio_offset = offset;
401	bp->bio_length = length;
402	bp->bio_data = ptr;
403	g_io_request(bp, cp);
404	error = biowait(bp, "gwrite");
405	g_destroy_bio(bp);
406	return (error);
407}
408