xref: /freebsd/sys/geom/gate/g_gate.c (revision ce3adf4362fcca6a43e500b2531f0038adbfbd21)
1 /*-
2  * Copyright (c) 2004-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3  * Copyright (c) 2009-2010 The FreeBSD Foundation
4  * All rights reserved.
5  *
6  * Portions of this software were developed by Pawel Jakub Dawidek
7  * under sponsorship from the FreeBSD Foundation.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/bio.h>
37 #include <sys/conf.h>
38 #include <sys/kernel.h>
39 #include <sys/kthread.h>
40 #include <sys/fcntl.h>
41 #include <sys/linker.h>
42 #include <sys/lock.h>
43 #include <sys/malloc.h>
44 #include <sys/mutex.h>
45 #include <sys/proc.h>
46 #include <sys/limits.h>
47 #include <sys/queue.h>
48 #include <sys/sbuf.h>
49 #include <sys/sysctl.h>
50 #include <sys/signalvar.h>
51 #include <sys/time.h>
52 #include <machine/atomic.h>
53 
54 #include <geom/geom.h>
55 #include <geom/gate/g_gate.h>
56 
57 FEATURE(geom_gate, "GEOM Gate module");
58 
59 static MALLOC_DEFINE(M_GATE, "gg_data", "GEOM Gate Data");
60 
61 SYSCTL_DECL(_kern_geom);
62 static SYSCTL_NODE(_kern_geom, OID_AUTO, gate, CTLFLAG_RW, 0,
63     "GEOM_GATE configuration");
64 static int g_gate_debug = 0;
65 TUNABLE_INT("kern.geom.gate.debug", &g_gate_debug);
66 SYSCTL_INT(_kern_geom_gate, OID_AUTO, debug, CTLFLAG_RW, &g_gate_debug, 0,
67     "Debug level");
68 static u_int g_gate_maxunits = 256;
69 TUNABLE_INT("kern.geom.gate.maxunits", &g_gate_maxunits);
70 SYSCTL_UINT(_kern_geom_gate, OID_AUTO, maxunits, CTLFLAG_RDTUN,
71     &g_gate_maxunits, 0, "Maximum number of ggate devices");
72 
73 struct g_class g_gate_class = {
74 	.name = G_GATE_CLASS_NAME,
75 	.version = G_VERSION,
76 };
77 
78 static struct cdev *status_dev;
79 static d_ioctl_t g_gate_ioctl;
80 static struct cdevsw g_gate_cdevsw = {
81 	.d_version =	D_VERSION,
82 	.d_ioctl =	g_gate_ioctl,
83 	.d_name =	G_GATE_CTL_NAME
84 };
85 
86 
87 static struct g_gate_softc **g_gate_units;
88 static u_int g_gate_nunits;
89 static struct mtx g_gate_units_lock;
90 
91 static int
92 g_gate_destroy(struct g_gate_softc *sc, boolean_t force)
93 {
94 	struct g_provider *pp;
95 	struct g_consumer *cp;
96 	struct g_geom *gp;
97 	struct bio *bp;
98 
99 	g_topology_assert();
100 	mtx_assert(&g_gate_units_lock, MA_OWNED);
101 	pp = sc->sc_provider;
102 	if (!force && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
103 		mtx_unlock(&g_gate_units_lock);
104 		return (EBUSY);
105 	}
106 	mtx_unlock(&g_gate_units_lock);
107 	mtx_lock(&sc->sc_queue_mtx);
108 	if ((sc->sc_flags & G_GATE_FLAG_DESTROY) == 0)
109 		sc->sc_flags |= G_GATE_FLAG_DESTROY;
110 	wakeup(sc);
111 	mtx_unlock(&sc->sc_queue_mtx);
112 	gp = pp->geom;
113 	pp->flags |= G_PF_WITHER;
114 	g_orphan_provider(pp, ENXIO);
115 	callout_drain(&sc->sc_callout);
116 	mtx_lock(&sc->sc_queue_mtx);
117 	while ((bp = bioq_first(&sc->sc_inqueue)) != NULL) {
118 		bioq_remove(&sc->sc_inqueue, bp);
119 		sc->sc_queue_count--;
120 		G_GATE_LOGREQ(1, bp, "Request canceled.");
121 		g_io_deliver(bp, ENXIO);
122 	}
123 	while ((bp = bioq_first(&sc->sc_outqueue)) != NULL) {
124 		bioq_remove(&sc->sc_outqueue, bp);
125 		sc->sc_queue_count--;
126 		G_GATE_LOGREQ(1, bp, "Request canceled.");
127 		g_io_deliver(bp, ENXIO);
128 	}
129 	mtx_unlock(&sc->sc_queue_mtx);
130 	g_topology_unlock();
131 	mtx_lock(&g_gate_units_lock);
132 	/* One reference is ours. */
133 	sc->sc_ref--;
134 	while (sc->sc_ref > 0)
135 		msleep(&sc->sc_ref, &g_gate_units_lock, 0, "gg:destroy", 0);
136 	g_gate_units[sc->sc_unit] = NULL;
137 	KASSERT(g_gate_nunits > 0, ("negative g_gate_nunits?"));
138 	g_gate_nunits--;
139 	mtx_unlock(&g_gate_units_lock);
140 	mtx_destroy(&sc->sc_queue_mtx);
141 	g_topology_lock();
142 	if ((cp = sc->sc_readcons) != NULL) {
143 		sc->sc_readcons = NULL;
144 		(void)g_access(cp, -1, 0, 0);
145 		g_detach(cp);
146 		g_destroy_consumer(cp);
147 	}
148 	G_GATE_DEBUG(1, "Device %s destroyed.", gp->name);
149 	gp->softc = NULL;
150 	g_wither_geom(gp, ENXIO);
151 	sc->sc_provider = NULL;
152 	free(sc, M_GATE);
153 	return (0);
154 }
155 
156 static int
157 g_gate_access(struct g_provider *pp, int dr, int dw, int de)
158 {
159 	struct g_gate_softc *sc;
160 
161 	if (dr <= 0 && dw <= 0 && de <= 0)
162 		return (0);
163 	sc = pp->geom->softc;
164 	if (sc == NULL || (sc->sc_flags & G_GATE_FLAG_DESTROY) != 0)
165 		return (ENXIO);
166 	/* XXX: Hack to allow read-only mounts. */
167 #if 0
168 	if ((sc->sc_flags & G_GATE_FLAG_READONLY) != 0 && dw > 0)
169 		return (EPERM);
170 #endif
171 	if ((sc->sc_flags & G_GATE_FLAG_WRITEONLY) != 0 && dr > 0)
172 		return (EPERM);
173 	return (0);
174 }
175 
176 static void
177 g_gate_queue_io(struct bio *bp)
178 {
179 	struct g_gate_softc *sc;
180 
181 	sc = bp->bio_to->geom->softc;
182 	if (sc == NULL || (sc->sc_flags & G_GATE_FLAG_DESTROY) != 0) {
183 		g_io_deliver(bp, ENXIO);
184 		return;
185 	}
186 
187 	mtx_lock(&sc->sc_queue_mtx);
188 
189 	if (sc->sc_queue_size > 0 && sc->sc_queue_count > sc->sc_queue_size) {
190 		mtx_unlock(&sc->sc_queue_mtx);
191 		G_GATE_LOGREQ(1, bp, "Queue full, request canceled.");
192 		g_io_deliver(bp, ENOMEM);
193 		return;
194 	}
195 
196 	bp->bio_driver1 = (void *)sc->sc_seq;
197 	sc->sc_seq++;
198 	sc->sc_queue_count++;
199 
200 	bioq_insert_tail(&sc->sc_inqueue, bp);
201 	wakeup(sc);
202 
203 	mtx_unlock(&sc->sc_queue_mtx);
204 }
205 
206 static void
207 g_gate_done(struct bio *cbp)
208 {
209 	struct bio *pbp;
210 
211 	pbp = cbp->bio_parent;
212 	if (cbp->bio_error == 0) {
213 		pbp->bio_completed = cbp->bio_completed;
214 		g_destroy_bio(cbp);
215 		pbp->bio_inbed++;
216 		g_io_deliver(pbp, 0);
217 	} else {
218 		/* If direct read failed, pass it through userland daemon. */
219 		g_destroy_bio(cbp);
220 		pbp->bio_children--;
221 		g_gate_queue_io(pbp);
222 	}
223 }
224 
225 static void
226 g_gate_start(struct bio *pbp)
227 {
228 	struct g_gate_softc *sc;
229 
230 	sc = pbp->bio_to->geom->softc;
231 	if (sc == NULL || (sc->sc_flags & G_GATE_FLAG_DESTROY) != 0) {
232 		g_io_deliver(pbp, ENXIO);
233 		return;
234 	}
235 	G_GATE_LOGREQ(2, pbp, "Request received.");
236 	switch (pbp->bio_cmd) {
237 	case BIO_READ:
238 		if (sc->sc_readcons != NULL) {
239 			struct bio *cbp;
240 
241 			cbp = g_clone_bio(pbp);
242 			if (cbp == NULL) {
243 				g_io_deliver(pbp, ENOMEM);
244 				return;
245 			}
246 			cbp->bio_done = g_gate_done;
247 			cbp->bio_offset = pbp->bio_offset + sc->sc_readoffset;
248 			cbp->bio_to = sc->sc_readcons->provider;
249 			g_io_request(cbp, sc->sc_readcons);
250 			return;
251 		}
252 		break;
253 	case BIO_DELETE:
254 	case BIO_WRITE:
255 	case BIO_FLUSH:
256 		/* XXX: Hack to allow read-only mounts. */
257 		if ((sc->sc_flags & G_GATE_FLAG_READONLY) != 0) {
258 			g_io_deliver(pbp, EPERM);
259 			return;
260 		}
261 		break;
262 	case BIO_GETATTR:
263 	default:
264 		G_GATE_LOGREQ(2, pbp, "Ignoring request.");
265 		g_io_deliver(pbp, EOPNOTSUPP);
266 		return;
267 	}
268 
269 	g_gate_queue_io(pbp);
270 }
271 
272 static struct g_gate_softc *
273 g_gate_hold(int unit, const char *name)
274 {
275 	struct g_gate_softc *sc = NULL;
276 
277 	mtx_lock(&g_gate_units_lock);
278 	if (unit >= 0 && unit < g_gate_maxunits)
279 		sc = g_gate_units[unit];
280 	else if (unit == G_GATE_NAME_GIVEN) {
281 		KASSERT(name != NULL, ("name is NULL"));
282 		for (unit = 0; unit < g_gate_maxunits; unit++) {
283 			if (g_gate_units[unit] == NULL)
284 				continue;
285 			if (strcmp(name,
286 			    g_gate_units[unit]->sc_provider->name) != 0) {
287 				continue;
288 			}
289 			sc = g_gate_units[unit];
290 			break;
291 		}
292 	}
293 	if (sc != NULL)
294 		sc->sc_ref++;
295 	mtx_unlock(&g_gate_units_lock);
296 	return (sc);
297 }
298 
299 static void
300 g_gate_release(struct g_gate_softc *sc)
301 {
302 
303 	g_topology_assert_not();
304 	mtx_lock(&g_gate_units_lock);
305 	sc->sc_ref--;
306 	KASSERT(sc->sc_ref >= 0, ("Negative sc_ref for %s.", sc->sc_name));
307 	if (sc->sc_ref == 0 && (sc->sc_flags & G_GATE_FLAG_DESTROY) != 0)
308 		wakeup(&sc->sc_ref);
309 	mtx_unlock(&g_gate_units_lock);
310 }
311 
312 static int
313 g_gate_getunit(int unit, int *errorp)
314 {
315 
316 	mtx_assert(&g_gate_units_lock, MA_OWNED);
317 	if (unit >= 0) {
318 		if (unit >= g_gate_maxunits)
319 			*errorp = EINVAL;
320 		else if (g_gate_units[unit] == NULL)
321 			return (unit);
322 		else
323 			*errorp = EEXIST;
324 	} else {
325 		for (unit = 0; unit < g_gate_maxunits; unit++) {
326 			if (g_gate_units[unit] == NULL)
327 				return (unit);
328 		}
329 		*errorp = ENFILE;
330 	}
331 	return (-1);
332 }
333 
334 static void
335 g_gate_guard(void *arg)
336 {
337 	struct g_gate_softc *sc;
338 	struct bintime curtime;
339 	struct bio *bp, *bp2;
340 
341 	sc = arg;
342 	binuptime(&curtime);
343 	g_gate_hold(sc->sc_unit, NULL);
344 	mtx_lock(&sc->sc_queue_mtx);
345 	TAILQ_FOREACH_SAFE(bp, &sc->sc_inqueue.queue, bio_queue, bp2) {
346 		if (curtime.sec - bp->bio_t0.sec < 5)
347 			continue;
348 		bioq_remove(&sc->sc_inqueue, bp);
349 		sc->sc_queue_count--;
350 		G_GATE_LOGREQ(1, bp, "Request timeout.");
351 		g_io_deliver(bp, EIO);
352 	}
353 	TAILQ_FOREACH_SAFE(bp, &sc->sc_outqueue.queue, bio_queue, bp2) {
354 		if (curtime.sec - bp->bio_t0.sec < 5)
355 			continue;
356 		bioq_remove(&sc->sc_outqueue, bp);
357 		sc->sc_queue_count--;
358 		G_GATE_LOGREQ(1, bp, "Request timeout.");
359 		g_io_deliver(bp, EIO);
360 	}
361 	mtx_unlock(&sc->sc_queue_mtx);
362 	if ((sc->sc_flags & G_GATE_FLAG_DESTROY) == 0) {
363 		callout_reset(&sc->sc_callout, sc->sc_timeout * hz,
364 		    g_gate_guard, sc);
365 	}
366 	g_gate_release(sc);
367 }
368 
369 static void
370 g_gate_orphan(struct g_consumer *cp)
371 {
372 	struct g_gate_softc *sc;
373 	struct g_geom *gp;
374 
375 	g_topology_assert();
376 	gp = cp->geom;
377 	sc = gp->softc;
378 	if (sc == NULL)
379 		return;
380 	KASSERT(cp == sc->sc_readcons, ("cp=%p sc_readcons=%p", cp,
381 	    sc->sc_readcons));
382 	sc->sc_readcons = NULL;
383 	G_GATE_DEBUG(1, "Destroying read consumer on provider %s orphan.",
384 	    cp->provider->name);
385 	(void)g_access(cp, -1, 0, 0);
386 	g_detach(cp);
387 	g_destroy_consumer(cp);
388 }
389 
390 static void
391 g_gate_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
392     struct g_consumer *cp, struct g_provider *pp)
393 {
394 	struct g_gate_softc *sc;
395 
396 	sc = gp->softc;
397 	if (sc == NULL || pp != NULL || cp != NULL)
398 		return;
399 	sc = g_gate_hold(sc->sc_unit, NULL);
400 	if (sc == NULL)
401 		return;
402 	if ((sc->sc_flags & G_GATE_FLAG_READONLY) != 0) {
403 		sbuf_printf(sb, "%s<access>%s</access>\n", indent, "read-only");
404 	} else if ((sc->sc_flags & G_GATE_FLAG_WRITEONLY) != 0) {
405 		sbuf_printf(sb, "%s<access>%s</access>\n", indent,
406 		    "write-only");
407 	} else {
408 		sbuf_printf(sb, "%s<access>%s</access>\n", indent,
409 		    "read-write");
410 	}
411 	if (sc->sc_readcons != NULL) {
412 		sbuf_printf(sb, "%s<read_offset>%jd</read_offset>\n",
413 		    indent, (intmax_t)sc->sc_readoffset);
414 		sbuf_printf(sb, "%s<read_provider>%s</read_provider>\n",
415 		    indent, sc->sc_readcons->provider->name);
416 	}
417 	sbuf_printf(sb, "%s<timeout>%u</timeout>\n", indent, sc->sc_timeout);
418 	sbuf_printf(sb, "%s<info>%s</info>\n", indent, sc->sc_info);
419 	sbuf_printf(sb, "%s<queue_count>%u</queue_count>\n", indent,
420 	    sc->sc_queue_count);
421 	sbuf_printf(sb, "%s<queue_size>%u</queue_size>\n", indent,
422 	    sc->sc_queue_size);
423 	sbuf_printf(sb, "%s<ref>%u</ref>\n", indent, sc->sc_ref);
424 	sbuf_printf(sb, "%s<unit>%d</unit>\n", indent, sc->sc_unit);
425 	g_topology_unlock();
426 	g_gate_release(sc);
427 	g_topology_lock();
428 }
429 
430 static int
431 g_gate_create(struct g_gate_ctl_create *ggio)
432 {
433 	struct g_gate_softc *sc;
434 	struct g_geom *gp;
435 	struct g_provider *pp, *ropp;
436 	struct g_consumer *cp;
437 	char name[NAME_MAX];
438 	int error = 0, unit;
439 
440 	if (ggio->gctl_mediasize <= 0) {
441 		G_GATE_DEBUG(1, "Invalid media size.");
442 		return (EINVAL);
443 	}
444 	if (ggio->gctl_sectorsize <= 0) {
445 		G_GATE_DEBUG(1, "Invalid sector size.");
446 		return (EINVAL);
447 	}
448 	if (!powerof2(ggio->gctl_sectorsize)) {
449 		G_GATE_DEBUG(1, "Invalid sector size.");
450 		return (EINVAL);
451 	}
452 	if ((ggio->gctl_mediasize % ggio->gctl_sectorsize) != 0) {
453 		G_GATE_DEBUG(1, "Invalid media size.");
454 		return (EINVAL);
455 	}
456 	if ((ggio->gctl_flags & G_GATE_FLAG_READONLY) != 0 &&
457 	    (ggio->gctl_flags & G_GATE_FLAG_WRITEONLY) != 0) {
458 		G_GATE_DEBUG(1, "Invalid flags.");
459 		return (EINVAL);
460 	}
461 	if (ggio->gctl_unit != G_GATE_UNIT_AUTO &&
462 	    ggio->gctl_unit != G_GATE_NAME_GIVEN &&
463 	    ggio->gctl_unit < 0) {
464 		G_GATE_DEBUG(1, "Invalid unit number.");
465 		return (EINVAL);
466 	}
467 	if (ggio->gctl_unit == G_GATE_NAME_GIVEN &&
468 	    ggio->gctl_name[0] == '\0') {
469 		G_GATE_DEBUG(1, "No device name.");
470 		return (EINVAL);
471 	}
472 
473 	sc = malloc(sizeof(*sc), M_GATE, M_WAITOK | M_ZERO);
474 	sc->sc_flags = (ggio->gctl_flags & G_GATE_USERFLAGS);
475 	strlcpy(sc->sc_info, ggio->gctl_info, sizeof(sc->sc_info));
476 	sc->sc_seq = 1;
477 	bioq_init(&sc->sc_inqueue);
478 	bioq_init(&sc->sc_outqueue);
479 	mtx_init(&sc->sc_queue_mtx, "gg:queue", NULL, MTX_DEF);
480 	sc->sc_queue_count = 0;
481 	sc->sc_queue_size = ggio->gctl_maxcount;
482 	if (sc->sc_queue_size > G_GATE_MAX_QUEUE_SIZE)
483 		sc->sc_queue_size = G_GATE_MAX_QUEUE_SIZE;
484 	sc->sc_timeout = ggio->gctl_timeout;
485 	callout_init(&sc->sc_callout, CALLOUT_MPSAFE);
486 
487 	mtx_lock(&g_gate_units_lock);
488 	sc->sc_unit = g_gate_getunit(ggio->gctl_unit, &error);
489 	if (sc->sc_unit < 0)
490 		goto fail1;
491 	if (ggio->gctl_unit == G_GATE_NAME_GIVEN)
492 		snprintf(name, sizeof(name), "%s", ggio->gctl_name);
493 	else {
494 		snprintf(name, sizeof(name), "%s%d", G_GATE_PROVIDER_NAME,
495 		    sc->sc_unit);
496 	}
497 	/* Check for name collision. */
498 	for (unit = 0; unit < g_gate_maxunits; unit++) {
499 		if (g_gate_units[unit] == NULL)
500 			continue;
501 		if (strcmp(name, g_gate_units[unit]->sc_name) != 0)
502 			continue;
503 		error = EEXIST;
504 		goto fail1;
505 	}
506 	sc->sc_name = name;
507 	g_gate_units[sc->sc_unit] = sc;
508 	g_gate_nunits++;
509 	mtx_unlock(&g_gate_units_lock);
510 
511 	g_topology_lock();
512 
513 	if (ggio->gctl_readprov[0] == '\0') {
514 		ropp = NULL;
515 	} else {
516 		ropp = g_provider_by_name(ggio->gctl_readprov);
517 		if (ropp == NULL) {
518 			G_GATE_DEBUG(1, "Provider %s doesn't exist.",
519 			    ggio->gctl_readprov);
520 			error = EINVAL;
521 			goto fail2;
522 		}
523 		if ((ggio->gctl_readoffset % ggio->gctl_sectorsize) != 0) {
524 			G_GATE_DEBUG(1, "Invalid read offset.");
525 			error = EINVAL;
526 			goto fail2;
527 		}
528 		if (ggio->gctl_mediasize + ggio->gctl_readoffset >
529 		    ropp->mediasize) {
530 			G_GATE_DEBUG(1, "Invalid read offset or media size.");
531 			error = EINVAL;
532 			goto fail2;
533 		}
534 	}
535 
536 	gp = g_new_geomf(&g_gate_class, "%s", name);
537 	gp->start = g_gate_start;
538 	gp->access = g_gate_access;
539 	gp->orphan = g_gate_orphan;
540 	gp->dumpconf = g_gate_dumpconf;
541 	gp->softc = sc;
542 
543 	if (ropp != NULL) {
544 		cp = g_new_consumer(gp);
545 		error = g_attach(cp, ropp);
546 		if (error != 0) {
547 			G_GATE_DEBUG(1, "Unable to attach to %s.", ropp->name);
548 			goto fail3;
549 		}
550 		error = g_access(cp, 1, 0, 0);
551 		if (error != 0) {
552 			G_GATE_DEBUG(1, "Unable to access %s.", ropp->name);
553 			g_detach(cp);
554 			goto fail3;
555 		}
556 		sc->sc_readcons = cp;
557 		sc->sc_readoffset = ggio->gctl_readoffset;
558 	}
559 
560 	ggio->gctl_unit = sc->sc_unit;
561 
562 	pp = g_new_providerf(gp, "%s", name);
563 	pp->mediasize = ggio->gctl_mediasize;
564 	pp->sectorsize = ggio->gctl_sectorsize;
565 	sc->sc_provider = pp;
566 	g_error_provider(pp, 0);
567 
568 	g_topology_unlock();
569 	mtx_lock(&g_gate_units_lock);
570 	sc->sc_name = sc->sc_provider->name;
571 	mtx_unlock(&g_gate_units_lock);
572 	G_GATE_DEBUG(1, "Device %s created.", gp->name);
573 
574 	if (sc->sc_timeout > 0) {
575 		callout_reset(&sc->sc_callout, sc->sc_timeout * hz,
576 		    g_gate_guard, sc);
577 	}
578 	return (0);
579 fail3:
580 	g_destroy_consumer(cp);
581 	g_destroy_geom(gp);
582 fail2:
583 	g_topology_unlock();
584 	mtx_lock(&g_gate_units_lock);
585 	g_gate_units[sc->sc_unit] = NULL;
586 	KASSERT(g_gate_nunits > 0, ("negative g_gate_nunits?"));
587 	g_gate_nunits--;
588 fail1:
589 	mtx_unlock(&g_gate_units_lock);
590 	mtx_destroy(&sc->sc_queue_mtx);
591 	free(sc, M_GATE);
592 	return (error);
593 }
594 
595 static int
596 g_gate_modify(struct g_gate_softc *sc, struct g_gate_ctl_modify *ggio)
597 {
598 	struct g_provider *pp;
599 	struct g_consumer *cp;
600 	int error;
601 
602 	if ((ggio->gctl_modify & GG_MODIFY_MEDIASIZE) != 0) {
603 		if (ggio->gctl_mediasize <= 0) {
604 			G_GATE_DEBUG(1, "Invalid media size.");
605 			return (EINVAL);
606 		}
607 		pp = sc->sc_provider;
608 		if ((ggio->gctl_mediasize % pp->sectorsize) != 0) {
609 			G_GATE_DEBUG(1, "Invalid media size.");
610 			return (EINVAL);
611 		}
612 		/* TODO */
613 		return (EOPNOTSUPP);
614 	}
615 
616 	if ((ggio->gctl_modify & GG_MODIFY_INFO) != 0)
617 		(void)strlcpy(sc->sc_info, ggio->gctl_info, sizeof(sc->sc_info));
618 
619 	cp = NULL;
620 
621 	if ((ggio->gctl_modify & GG_MODIFY_READPROV) != 0) {
622 		g_topology_lock();
623 		if (sc->sc_readcons != NULL) {
624 			cp = sc->sc_readcons;
625 			sc->sc_readcons = NULL;
626 			(void)g_access(cp, -1, 0, 0);
627 			g_detach(cp);
628 			g_destroy_consumer(cp);
629 		}
630 		if (ggio->gctl_readprov[0] != '\0') {
631 			pp = g_provider_by_name(ggio->gctl_readprov);
632 			if (pp == NULL) {
633 				g_topology_unlock();
634 				G_GATE_DEBUG(1, "Provider %s doesn't exist.",
635 				    ggio->gctl_readprov);
636 				return (EINVAL);
637 			}
638 			cp = g_new_consumer(sc->sc_provider->geom);
639 			error = g_attach(cp, pp);
640 			if (error != 0) {
641 				G_GATE_DEBUG(1, "Unable to attach to %s.",
642 				    pp->name);
643 			} else {
644 				error = g_access(cp, 1, 0, 0);
645 				if (error != 0) {
646 					G_GATE_DEBUG(1, "Unable to access %s.",
647 					    pp->name);
648 					g_detach(cp);
649 				}
650 			}
651 			if (error != 0) {
652 				g_destroy_consumer(cp);
653 				g_topology_unlock();
654 				return (error);
655 			}
656 		}
657 	} else {
658 		cp = sc->sc_readcons;
659 	}
660 
661 	if ((ggio->gctl_modify & GG_MODIFY_READOFFSET) != 0) {
662 		if (cp == NULL) {
663 			G_GATE_DEBUG(1, "No read provider.");
664 			return (EINVAL);
665 		}
666 		pp = sc->sc_provider;
667 		if ((ggio->gctl_readoffset % pp->sectorsize) != 0) {
668 			G_GATE_DEBUG(1, "Invalid read offset.");
669 			return (EINVAL);
670 		}
671 		if (pp->mediasize + ggio->gctl_readoffset >
672 		    cp->provider->mediasize) {
673 			G_GATE_DEBUG(1, "Invalid read offset or media size.");
674 			return (EINVAL);
675 		}
676 		sc->sc_readoffset = ggio->gctl_readoffset;
677 	}
678 
679 	if ((ggio->gctl_modify & GG_MODIFY_READPROV) != 0) {
680 		sc->sc_readcons = cp;
681 		g_topology_unlock();
682 	}
683 
684 	return (0);
685 }
686 
687 #define	G_GATE_CHECK_VERSION(ggio)	do {				\
688 	if ((ggio)->gctl_version != G_GATE_VERSION) {			\
689 		printf("Version mismatch %d != %d.\n",			\
690 		    ggio->gctl_version, G_GATE_VERSION);		\
691 		return (EINVAL);					\
692 	}								\
693 } while (0)
694 static int
695 g_gate_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
696 {
697 	struct g_gate_softc *sc;
698 	struct bio *bp;
699 	int error = 0;
700 
701 	G_GATE_DEBUG(4, "ioctl(%s, %lx, %p, %x, %p)", devtoname(dev), cmd, addr,
702 	    flags, td);
703 
704 	switch (cmd) {
705 	case G_GATE_CMD_CREATE:
706 	    {
707 		struct g_gate_ctl_create *ggio = (void *)addr;
708 
709 		G_GATE_CHECK_VERSION(ggio);
710 		error = g_gate_create(ggio);
711 		/*
712 		 * Reset TDP_GEOM flag.
713 		 * There are pending events for sure, because we just created
714 		 * new provider and other classes want to taste it, but we
715 		 * cannot answer on I/O requests until we're here.
716 		 */
717 		td->td_pflags &= ~TDP_GEOM;
718 		return (error);
719 	    }
720 	case G_GATE_CMD_MODIFY:
721 	    {
722 		struct g_gate_ctl_modify *ggio = (void *)addr;
723 
724 		G_GATE_CHECK_VERSION(ggio);
725 		sc = g_gate_hold(ggio->gctl_unit, NULL);
726 		if (sc == NULL)
727 			return (ENXIO);
728 		error = g_gate_modify(sc, ggio);
729 		g_gate_release(sc);
730 		return (error);
731 	    }
732 	case G_GATE_CMD_DESTROY:
733 	    {
734 		struct g_gate_ctl_destroy *ggio = (void *)addr;
735 
736 		G_GATE_CHECK_VERSION(ggio);
737 		sc = g_gate_hold(ggio->gctl_unit, ggio->gctl_name);
738 		if (sc == NULL)
739 			return (ENXIO);
740 		g_topology_lock();
741 		mtx_lock(&g_gate_units_lock);
742 		error = g_gate_destroy(sc, ggio->gctl_force);
743 		g_topology_unlock();
744 		if (error != 0)
745 			g_gate_release(sc);
746 		return (error);
747 	    }
748 	case G_GATE_CMD_CANCEL:
749 	    {
750 		struct g_gate_ctl_cancel *ggio = (void *)addr;
751 		struct bio *tbp, *lbp;
752 
753 		G_GATE_CHECK_VERSION(ggio);
754 		sc = g_gate_hold(ggio->gctl_unit, ggio->gctl_name);
755 		if (sc == NULL)
756 			return (ENXIO);
757 		lbp = NULL;
758 		mtx_lock(&sc->sc_queue_mtx);
759 		TAILQ_FOREACH_SAFE(bp, &sc->sc_outqueue.queue, bio_queue, tbp) {
760 			if (ggio->gctl_seq == 0 ||
761 			    ggio->gctl_seq == (uintptr_t)bp->bio_driver1) {
762 				G_GATE_LOGREQ(1, bp, "Request canceled.");
763 				bioq_remove(&sc->sc_outqueue, bp);
764 				/*
765 				 * Be sure to put requests back onto incoming
766 				 * queue in the proper order.
767 				 */
768 				if (lbp == NULL)
769 					bioq_insert_head(&sc->sc_inqueue, bp);
770 				else {
771 					TAILQ_INSERT_AFTER(&sc->sc_inqueue.queue,
772 					    lbp, bp, bio_queue);
773 				}
774 				lbp = bp;
775 				/*
776 				 * If only one request was canceled, leave now.
777 				 */
778 				if (ggio->gctl_seq != 0)
779 					break;
780 			}
781 		}
782 		if (ggio->gctl_unit == G_GATE_NAME_GIVEN)
783 			ggio->gctl_unit = sc->sc_unit;
784 		mtx_unlock(&sc->sc_queue_mtx);
785 		g_gate_release(sc);
786 		return (error);
787 	    }
788 	case G_GATE_CMD_START:
789 	    {
790 		struct g_gate_ctl_io *ggio = (void *)addr;
791 
792 		G_GATE_CHECK_VERSION(ggio);
793 		sc = g_gate_hold(ggio->gctl_unit, NULL);
794 		if (sc == NULL)
795 			return (ENXIO);
796 		error = 0;
797 		for (;;) {
798 			mtx_lock(&sc->sc_queue_mtx);
799 			bp = bioq_first(&sc->sc_inqueue);
800 			if (bp != NULL)
801 				break;
802 			if ((sc->sc_flags & G_GATE_FLAG_DESTROY) != 0) {
803 				ggio->gctl_error = ECANCELED;
804 				mtx_unlock(&sc->sc_queue_mtx);
805 				goto start_end;
806 			}
807 			if (msleep(sc, &sc->sc_queue_mtx,
808 			    PPAUSE | PDROP | PCATCH, "ggwait", 0) != 0) {
809 				ggio->gctl_error = ECANCELED;
810 				goto start_end;
811 			}
812 		}
813 		ggio->gctl_cmd = bp->bio_cmd;
814 		if (bp->bio_cmd == BIO_WRITE &&
815 		    bp->bio_length > ggio->gctl_length) {
816 			mtx_unlock(&sc->sc_queue_mtx);
817 			ggio->gctl_length = bp->bio_length;
818 			ggio->gctl_error = ENOMEM;
819 			goto start_end;
820 		}
821 		bioq_remove(&sc->sc_inqueue, bp);
822 		bioq_insert_tail(&sc->sc_outqueue, bp);
823 		mtx_unlock(&sc->sc_queue_mtx);
824 
825 		ggio->gctl_seq = (uintptr_t)bp->bio_driver1;
826 		ggio->gctl_offset = bp->bio_offset;
827 		ggio->gctl_length = bp->bio_length;
828 
829 		switch (bp->bio_cmd) {
830 		case BIO_READ:
831 		case BIO_DELETE:
832 		case BIO_FLUSH:
833 			break;
834 		case BIO_WRITE:
835 			error = copyout(bp->bio_data, ggio->gctl_data,
836 			    bp->bio_length);
837 			if (error != 0) {
838 				mtx_lock(&sc->sc_queue_mtx);
839 				bioq_remove(&sc->sc_outqueue, bp);
840 				bioq_insert_head(&sc->sc_inqueue, bp);
841 				mtx_unlock(&sc->sc_queue_mtx);
842 				goto start_end;
843 			}
844 			break;
845 		}
846 start_end:
847 		g_gate_release(sc);
848 		return (error);
849 	    }
850 	case G_GATE_CMD_DONE:
851 	    {
852 		struct g_gate_ctl_io *ggio = (void *)addr;
853 
854 		G_GATE_CHECK_VERSION(ggio);
855 		sc = g_gate_hold(ggio->gctl_unit, NULL);
856 		if (sc == NULL)
857 			return (ENOENT);
858 		error = 0;
859 		mtx_lock(&sc->sc_queue_mtx);
860 		TAILQ_FOREACH(bp, &sc->sc_outqueue.queue, bio_queue) {
861 			if (ggio->gctl_seq == (uintptr_t)bp->bio_driver1)
862 				break;
863 		}
864 		if (bp != NULL) {
865 			bioq_remove(&sc->sc_outqueue, bp);
866 			sc->sc_queue_count--;
867 		}
868 		mtx_unlock(&sc->sc_queue_mtx);
869 		if (bp == NULL) {
870 			/*
871 			 * Request was probably canceled.
872 			 */
873 			goto done_end;
874 		}
875 		if (ggio->gctl_error == EAGAIN) {
876 			bp->bio_error = 0;
877 			G_GATE_LOGREQ(1, bp, "Request desisted.");
878 			mtx_lock(&sc->sc_queue_mtx);
879 			sc->sc_queue_count++;
880 			bioq_insert_head(&sc->sc_inqueue, bp);
881 			wakeup(sc);
882 			mtx_unlock(&sc->sc_queue_mtx);
883 		} else {
884 			bp->bio_error = ggio->gctl_error;
885 			if (bp->bio_error == 0) {
886 				bp->bio_completed = bp->bio_length;
887 				switch (bp->bio_cmd) {
888 				case BIO_READ:
889 					error = copyin(ggio->gctl_data,
890 					    bp->bio_data, bp->bio_length);
891 					if (error != 0)
892 						bp->bio_error = error;
893 					break;
894 				case BIO_DELETE:
895 				case BIO_WRITE:
896 				case BIO_FLUSH:
897 					break;
898 				}
899 			}
900 			G_GATE_LOGREQ(2, bp, "Request done.");
901 			g_io_deliver(bp, bp->bio_error);
902 		}
903 done_end:
904 		g_gate_release(sc);
905 		return (error);
906 	    }
907 	}
908 	return (ENOIOCTL);
909 }
910 
911 static void
912 g_gate_device(void)
913 {
914 
915 	status_dev = make_dev(&g_gate_cdevsw, 0x0, UID_ROOT, GID_WHEEL, 0600,
916 	    G_GATE_CTL_NAME);
917 }
918 
919 static int
920 g_gate_modevent(module_t mod, int type, void *data)
921 {
922 	int error = 0;
923 
924 	switch (type) {
925 	case MOD_LOAD:
926 		mtx_init(&g_gate_units_lock, "gg_units_lock", NULL, MTX_DEF);
927 		g_gate_units = malloc(g_gate_maxunits * sizeof(g_gate_units[0]),
928 		    M_GATE, M_WAITOK | M_ZERO);
929 		g_gate_nunits = 0;
930 		g_gate_device();
931 		break;
932 	case MOD_UNLOAD:
933 		mtx_lock(&g_gate_units_lock);
934 		if (g_gate_nunits > 0) {
935 			mtx_unlock(&g_gate_units_lock);
936 			error = EBUSY;
937 			break;
938 		}
939 		mtx_unlock(&g_gate_units_lock);
940 		mtx_destroy(&g_gate_units_lock);
941 		if (status_dev != 0)
942 			destroy_dev(status_dev);
943 		free(g_gate_units, M_GATE);
944 		break;
945 	default:
946 		return (EOPNOTSUPP);
947 		break;
948 	}
949 
950 	return (error);
951 }
952 static moduledata_t g_gate_module = {
953 	G_GATE_MOD_NAME,
954 	g_gate_modevent,
955 	NULL
956 };
957 DECLARE_MODULE(geom_gate, g_gate_module, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
958 DECLARE_GEOM_CLASS(g_gate_class, g_gate);
959