FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_subr.c
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: src/sys/geom/geom_subr.c,v 1.97 2008/08/09 11:14:05 des Exp $");
38
39 #include "opt_ddb.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/devicestat.h>
44 #include <sys/kernel.h>
45 #include <sys/malloc.h>
46 #include <sys/bio.h>
47 #include <sys/sysctl.h>
48 #include <sys/proc.h>
49 #include <sys/kthread.h>
50 #include <sys/lock.h>
51 #include <sys/mutex.h>
52 #include <sys/errno.h>
53 #include <sys/sbuf.h>
54 #include <geom/geom.h>
55 #include <geom/geom_int.h>
56 #include <machine/stdarg.h>
57
58 #ifdef DDB
59 #include <ddb/ddb.h>
60 #endif
61
62 struct class_list_head g_classes = LIST_HEAD_INITIALIZER(g_classes);
63 static struct g_tailq_head geoms = TAILQ_HEAD_INITIALIZER(geoms);
64 char *g_wait_event, *g_wait_up, *g_wait_down, *g_wait_sim;
65
66 struct g_hh00 {
67 struct g_class *mp;
68 int error;
69 int post;
70 };
71
72 /*
73 * This event offers a new class a chance to taste all preexisting providers.
74 */
75 static void
76 g_load_class(void *arg, int flag)
77 {
78 struct g_hh00 *hh;
79 struct g_class *mp2, *mp;
80 struct g_geom *gp;
81 struct g_provider *pp;
82
83 g_topology_assert();
84 if (flag == EV_CANCEL) /* XXX: can't happen ? */
85 return;
86 if (g_shutdown)
87 return;
88
89 hh = arg;
90 mp = hh->mp;
91 hh->error = 0;
92 if (hh->post) {
93 g_free(hh);
94 hh = NULL;
95 }
96 g_trace(G_T_TOPOLOGY, "g_load_class(%s)", mp->name);
97 KASSERT(mp->name != NULL && *mp->name != '\0',
98 ("GEOM class has no name"));
99 LIST_FOREACH(mp2, &g_classes, class) {
100 if (mp2 == mp) {
101 printf("The GEOM class %s is already loaded.\n",
102 mp2->name);
103 if (hh != NULL)
104 hh->error = EEXIST;
105 return;
106 } else if (strcmp(mp2->name, mp->name) == 0) {
107 printf("A GEOM class %s is already loaded.\n",
108 mp2->name);
109 if (hh != NULL)
110 hh->error = EEXIST;
111 return;
112 }
113 }
114
115 LIST_INIT(&mp->geom);
116 LIST_INSERT_HEAD(&g_classes, mp, class);
117 if (mp->init != NULL)
118 mp->init(mp);
119 if (mp->taste == NULL)
120 return;
121 LIST_FOREACH(mp2, &g_classes, class) {
122 if (mp == mp2)
123 continue;
124 LIST_FOREACH(gp, &mp2->geom, geom) {
125 LIST_FOREACH(pp, &gp->provider, provider) {
126 mp->taste(mp, pp, 0);
127 g_topology_assert();
128 }
129 }
130 }
131 }
132
133 static void
134 g_unload_class(void *arg, int flag)
135 {
136 struct g_hh00 *hh;
137 struct g_class *mp;
138 struct g_geom *gp;
139 struct g_provider *pp;
140 struct g_consumer *cp;
141 int error;
142
143 g_topology_assert();
144 hh = arg;
145 mp = hh->mp;
146 G_VALID_CLASS(mp);
147 g_trace(G_T_TOPOLOGY, "g_unload_class(%s)", mp->name);
148
149 /*
150 * We allow unloading if we have no geoms, or a class
151 * method we can use to get rid of them.
152 */
153 if (!LIST_EMPTY(&mp->geom) && mp->destroy_geom == NULL) {
154 hh->error = EOPNOTSUPP;
155 return;
156 }
157
158 /* We refuse to unload if anything is open */
159 LIST_FOREACH(gp, &mp->geom, geom) {
160 LIST_FOREACH(pp, &gp->provider, provider)
161 if (pp->acr || pp->acw || pp->ace) {
162 hh->error = EBUSY;
163 return;
164 }
165 LIST_FOREACH(cp, &gp->consumer, consumer)
166 if (cp->acr || cp->acw || cp->ace) {
167 hh->error = EBUSY;
168 return;
169 }
170 }
171
172 /* Bar new entries */
173 mp->taste = NULL;
174 mp->config = NULL;
175
176 error = 0;
177 for (;;) {
178 gp = LIST_FIRST(&mp->geom);
179 if (gp == NULL)
180 break;
181 error = mp->destroy_geom(NULL, mp, gp);
182 if (error != 0)
183 break;
184 }
185 if (error == 0) {
186 if (mp->fini != NULL)
187 mp->fini(mp);
188 LIST_REMOVE(mp, class);
189 }
190 hh->error = error;
191 return;
192 }
193
194 int
195 g_modevent(module_t mod, int type, void *data)
196 {
197 struct g_hh00 *hh;
198 int error;
199 static int g_ignition;
200 struct g_class *mp;
201
202 mp = data;
203 if (mp->version != G_VERSION) {
204 printf("GEOM class %s has Wrong version %x\n",
205 mp->name, mp->version);
206 return (EINVAL);
207 }
208 if (!g_ignition) {
209 g_ignition++;
210 g_init();
211 }
212 hh = g_malloc(sizeof *hh, M_WAITOK | M_ZERO);
213 hh->mp = data;
214 error = EOPNOTSUPP;
215 switch (type) {
216 case MOD_LOAD:
217 g_trace(G_T_TOPOLOGY, "g_modevent(%s, LOAD)", hh->mp->name);
218 /*
219 * Once the system is not cold, MOD_LOAD calls will be
220 * from the userland and the g_event thread will be able
221 * to acknowledge their completion.
222 */
223 if (cold) {
224 hh->post = 1;
225 error = g_post_event(g_load_class, hh, M_WAITOK, NULL);
226 } else {
227 error = g_waitfor_event(g_load_class, hh, M_WAITOK,
228 NULL);
229 if (error == 0)
230 error = hh->error;
231 g_free(hh);
232 }
233 break;
234 case MOD_UNLOAD:
235 g_trace(G_T_TOPOLOGY, "g_modevent(%s, UNLOAD)", hh->mp->name);
236 error = g_waitfor_event(g_unload_class, hh, M_WAITOK, NULL);
237 if (error == 0)
238 error = hh->error;
239 if (error == 0) {
240 KASSERT(LIST_EMPTY(&hh->mp->geom),
241 ("Unloaded class (%s) still has geom", hh->mp->name));
242 }
243 g_free(hh);
244 break;
245 default:
246 g_free(hh);
247 break;
248 }
249 return (error);
250 }
251
252 static void
253 g_retaste_event(void *arg, int flag)
254 {
255 struct g_class *cp, *mp;
256 struct g_geom *gp, *gp2;
257 struct g_hh00 *hh;
258 struct g_provider *pp;
259
260 g_topology_assert();
261 if (flag == EV_CANCEL) /* XXX: can't happen ? */
262 return;
263 if (g_shutdown)
264 return;
265
266 hh = arg;
267 mp = hh->mp;
268 hh->error = 0;
269 if (hh->post) {
270 g_free(hh);
271 hh = NULL;
272 }
273 g_trace(G_T_TOPOLOGY, "g_retaste(%s)", mp->name);
274
275 LIST_FOREACH(cp, &g_classes, class) {
276 LIST_FOREACH(gp, &cp->geom, geom) {
277 LIST_FOREACH(pp, &gp->provider, provider) {
278 if (pp->acr || pp->acw || pp->ace)
279 continue;
280 LIST_FOREACH(gp2, &mp->geom, geom) {
281 if (!strcmp(pp->name, gp2->name))
282 break;
283 }
284 if (gp2 != NULL)
285 g_wither_geom(gp2, ENXIO);
286 mp->taste(mp, pp, 0);
287 g_topology_assert();
288 }
289 }
290 }
291 }
292
293 int
294 g_retaste(struct g_class *mp)
295 {
296 struct g_hh00 *hh;
297 int error;
298
299 if (mp->taste == NULL)
300 return (EINVAL);
301
302 hh = g_malloc(sizeof *hh, M_WAITOK | M_ZERO);
303 hh->mp = mp;
304
305 if (cold) {
306 hh->post = 1;
307 error = g_post_event(g_retaste_event, hh, M_WAITOK, NULL);
308 } else {
309 error = g_waitfor_event(g_retaste_event, hh, M_WAITOK, NULL);
310 if (error == 0)
311 error = hh->error;
312 g_free(hh);
313 }
314
315 return (error);
316 }
317
318 struct g_geom *
319 g_new_geomf(struct g_class *mp, const char *fmt, ...)
320 {
321 struct g_geom *gp;
322 va_list ap;
323 struct sbuf *sb;
324
325 g_topology_assert();
326 G_VALID_CLASS(mp);
327 sb = sbuf_new_auto();
328 va_start(ap, fmt);
329 sbuf_vprintf(sb, fmt, ap);
330 va_end(ap);
331 sbuf_finish(sb);
332 gp = g_malloc(sizeof *gp, M_WAITOK | M_ZERO);
333 gp->name = g_malloc(sbuf_len(sb) + 1, M_WAITOK | M_ZERO);
334 gp->class = mp;
335 gp->rank = 1;
336 LIST_INIT(&gp->consumer);
337 LIST_INIT(&gp->provider);
338 LIST_INSERT_HEAD(&mp->geom, gp, geom);
339 TAILQ_INSERT_HEAD(&geoms, gp, geoms);
340 strcpy(gp->name, sbuf_data(sb));
341 sbuf_delete(sb);
342 /* Fill in defaults from class */
343 gp->start = mp->start;
344 gp->spoiled = mp->spoiled;
345 gp->dumpconf = mp->dumpconf;
346 gp->access = mp->access;
347 gp->orphan = mp->orphan;
348 gp->ioctl = mp->ioctl;
349 return (gp);
350 }
351
352 void
353 g_destroy_geom(struct g_geom *gp)
354 {
355
356 g_topology_assert();
357 G_VALID_GEOM(gp);
358 g_trace(G_T_TOPOLOGY, "g_destroy_geom(%p(%s))", gp, gp->name);
359 KASSERT(LIST_EMPTY(&gp->consumer),
360 ("g_destroy_geom(%s) with consumer(s) [%p]",
361 gp->name, LIST_FIRST(&gp->consumer)));
362 KASSERT(LIST_EMPTY(&gp->provider),
363 ("g_destroy_geom(%s) with provider(s) [%p]",
364 gp->name, LIST_FIRST(&gp->provider)));
365 g_cancel_event(gp);
366 LIST_REMOVE(gp, geom);
367 TAILQ_REMOVE(&geoms, gp, geoms);
368 g_free(gp->name);
369 g_free(gp);
370 }
371
372 /*
373 * This function is called (repeatedly) until the has withered away.
374 */
375 void
376 g_wither_geom(struct g_geom *gp, int error)
377 {
378 struct g_provider *pp;
379
380 g_topology_assert();
381 G_VALID_GEOM(gp);
382 g_trace(G_T_TOPOLOGY, "g_wither_geom(%p(%s))", gp, gp->name);
383 if (!(gp->flags & G_GEOM_WITHER)) {
384 gp->flags |= G_GEOM_WITHER;
385 LIST_FOREACH(pp, &gp->provider, provider)
386 if (!(pp->flags & G_PF_ORPHAN))
387 g_orphan_provider(pp, error);
388 }
389 g_do_wither();
390 }
391
392 /*
393 * Convenience function to destroy a particular provider.
394 */
395 void
396 g_wither_provider(struct g_provider *pp, int error)
397 {
398
399 pp->flags |= G_PF_WITHER;
400 if (!(pp->flags & G_PF_ORPHAN))
401 g_orphan_provider(pp, error);
402 }
403
404 /*
405 * This function is called (repeatedly) until the has withered away.
406 */
407 void
408 g_wither_geom_close(struct g_geom *gp, int error)
409 {
410 struct g_consumer *cp;
411
412 g_topology_assert();
413 G_VALID_GEOM(gp);
414 g_trace(G_T_TOPOLOGY, "g_wither_geom_close(%p(%s))", gp, gp->name);
415 LIST_FOREACH(cp, &gp->consumer, consumer)
416 if (cp->acr || cp->acw || cp->ace)
417 g_access(cp, -cp->acr, -cp->acw, -cp->ace);
418 g_wither_geom(gp, error);
419 }
420
421 /*
422 * This function is called (repeatedly) until we cant wash away more
423 * withered bits at present. Return value contains two bits. Bit 0
424 * set means "withering stuff we can't wash now", bit 1 means "call
425 * me again, there may be stuff I didn't get the first time around.
426 */
427 int
428 g_wither_washer()
429 {
430 struct g_class *mp;
431 struct g_geom *gp, *gp2;
432 struct g_provider *pp, *pp2;
433 struct g_consumer *cp, *cp2;
434 int result;
435
436 result = 0;
437 g_topology_assert();
438 LIST_FOREACH(mp, &g_classes, class) {
439 LIST_FOREACH_SAFE(gp, &mp->geom, geom, gp2) {
440 LIST_FOREACH_SAFE(pp, &gp->provider, provider, pp2) {
441 if (!(pp->flags & G_PF_WITHER))
442 continue;
443 if (LIST_EMPTY(&pp->consumers))
444 g_destroy_provider(pp);
445 else
446 result |= 1;
447 }
448 if (!(gp->flags & G_GEOM_WITHER))
449 continue;
450 LIST_FOREACH_SAFE(pp, &gp->provider, provider, pp2) {
451 if (LIST_EMPTY(&pp->consumers))
452 g_destroy_provider(pp);
453 else
454 result |= 1;
455 }
456 LIST_FOREACH_SAFE(cp, &gp->consumer, consumer, cp2) {
457 if (cp->acr || cp->acw || cp->ace) {
458 result |= 1;
459 continue;
460 }
461 if (cp->provider != NULL)
462 g_detach(cp);
463 g_destroy_consumer(cp);
464 result |= 2;
465 }
466 if (LIST_EMPTY(&gp->provider) &&
467 LIST_EMPTY(&gp->consumer))
468 g_destroy_geom(gp);
469 else
470 result |= 1;
471 }
472 }
473 return (result);
474 }
475
476 struct g_consumer *
477 g_new_consumer(struct g_geom *gp)
478 {
479 struct g_consumer *cp;
480
481 g_topology_assert();
482 G_VALID_GEOM(gp);
483 KASSERT(!(gp->flags & G_GEOM_WITHER),
484 ("g_new_consumer on WITHERing geom(%s) (class %s)",
485 gp->name, gp->class->name));
486 KASSERT(gp->orphan != NULL,
487 ("g_new_consumer on geom(%s) (class %s) without orphan",
488 gp->name, gp->class->name));
489
490 cp = g_malloc(sizeof *cp, M_WAITOK | M_ZERO);
491 cp->geom = gp;
492 cp->stat = devstat_new_entry(cp, -1, 0, DEVSTAT_ALL_SUPPORTED,
493 DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
494 LIST_INSERT_HEAD(&gp->consumer, cp, consumer);
495 return(cp);
496 }
497
498 void
499 g_destroy_consumer(struct g_consumer *cp)
500 {
501 struct g_geom *gp;
502
503 g_topology_assert();
504 G_VALID_CONSUMER(cp);
505 g_trace(G_T_TOPOLOGY, "g_destroy_consumer(%p)", cp);
506 KASSERT (cp->provider == NULL, ("g_destroy_consumer but attached"));
507 KASSERT (cp->acr == 0, ("g_destroy_consumer with acr"));
508 KASSERT (cp->acw == 0, ("g_destroy_consumer with acw"));
509 KASSERT (cp->ace == 0, ("g_destroy_consumer with ace"));
510 g_cancel_event(cp);
511 gp = cp->geom;
512 LIST_REMOVE(cp, consumer);
513 devstat_remove_entry(cp->stat);
514 g_free(cp);
515 if (gp->flags & G_GEOM_WITHER)
516 g_do_wither();
517 }
518
519 static void
520 g_new_provider_event(void *arg, int flag)
521 {
522 struct g_class *mp;
523 struct g_provider *pp;
524 struct g_consumer *cp;
525 int i;
526
527 g_topology_assert();
528 if (flag == EV_CANCEL)
529 return;
530 if (g_shutdown)
531 return;
532 pp = arg;
533 G_VALID_PROVIDER(pp);
534 KASSERT(!(pp->flags & G_PF_WITHER),
535 ("g_new_provider_event but withered"));
536 LIST_FOREACH(mp, &g_classes, class) {
537 if (mp->taste == NULL)
538 continue;
539 i = 1;
540 LIST_FOREACH(cp, &pp->consumers, consumers)
541 if (cp->geom->class == mp)
542 i = 0;
543 if (!i)
544 continue;
545 mp->taste(mp, pp, 0);
546 g_topology_assert();
547 }
548 }
549
550
551 struct g_provider *
552 g_new_providerf(struct g_geom *gp, const char *fmt, ...)
553 {
554 struct g_provider *pp;
555 struct sbuf *sb;
556 va_list ap;
557
558 g_topology_assert();
559 G_VALID_GEOM(gp);
560 KASSERT(gp->access != NULL,
561 ("new provider on geom(%s) without ->access (class %s)",
562 gp->name, gp->class->name));
563 KASSERT(gp->start != NULL,
564 ("new provider on geom(%s) without ->start (class %s)",
565 gp->name, gp->class->name));
566 KASSERT(!(gp->flags & G_GEOM_WITHER),
567 ("new provider on WITHERing geom(%s) (class %s)",
568 gp->name, gp->class->name));
569 sb = sbuf_new_auto();
570 va_start(ap, fmt);
571 sbuf_vprintf(sb, fmt, ap);
572 va_end(ap);
573 sbuf_finish(sb);
574 pp = g_malloc(sizeof *pp + sbuf_len(sb) + 1, M_WAITOK | M_ZERO);
575 pp->name = (char *)(pp + 1);
576 strcpy(pp->name, sbuf_data(sb));
577 sbuf_delete(sb);
578 LIST_INIT(&pp->consumers);
579 pp->error = ENXIO;
580 pp->geom = gp;
581 pp->stat = devstat_new_entry(pp, -1, 0, DEVSTAT_ALL_SUPPORTED,
582 DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
583 LIST_INSERT_HEAD(&gp->provider, pp, provider);
584 g_post_event(g_new_provider_event, pp, M_WAITOK, pp, gp, NULL);
585 return (pp);
586 }
587
588 void
589 g_error_provider(struct g_provider *pp, int error)
590 {
591
592 /* G_VALID_PROVIDER(pp); We may not have g_topology */
593 pp->error = error;
594 }
595
596 struct g_provider *
597 g_provider_by_name(char const *arg)
598 {
599 struct g_class *cp;
600 struct g_geom *gp;
601 struct g_provider *pp;
602
603 LIST_FOREACH(cp, &g_classes, class) {
604 LIST_FOREACH(gp, &cp->geom, geom) {
605 LIST_FOREACH(pp, &gp->provider, provider) {
606 if (!strcmp(arg, pp->name))
607 return (pp);
608 }
609 }
610 }
611 return (NULL);
612 }
613
614 void
615 g_destroy_provider(struct g_provider *pp)
616 {
617 struct g_geom *gp;
618
619 g_topology_assert();
620 G_VALID_PROVIDER(pp);
621 KASSERT(LIST_EMPTY(&pp->consumers),
622 ("g_destroy_provider but attached"));
623 KASSERT (pp->acr == 0, ("g_destroy_provider with acr"));
624 KASSERT (pp->acw == 0, ("g_destroy_provider with acw"));
625 KASSERT (pp->ace == 0, ("g_destroy_provider with ace"));
626 g_cancel_event(pp);
627 LIST_REMOVE(pp, provider);
628 gp = pp->geom;
629 devstat_remove_entry(pp->stat);
630 g_free(pp);
631 if ((gp->flags & G_GEOM_WITHER))
632 g_do_wither();
633 }
634
635 /*
636 * We keep the "geoms" list sorted by topological order (== increasing
637 * numerical rank) at all times.
638 * When an attach is done, the attaching geoms rank is invalidated
639 * and it is moved to the tail of the list.
640 * All geoms later in the sequence has their ranks reevaluated in
641 * sequence. If we cannot assign rank to a geom because it's
642 * prerequisites do not have rank, we move that element to the tail
643 * of the sequence with invalid rank as well.
644 * At some point we encounter our original geom and if we stil fail
645 * to assign it a rank, there must be a loop and we fail back to
646 * g_attach() which detach again and calls redo_rank again
647 * to fix up the damage.
648 * It would be much simpler code wise to do it recursively, but we
649 * can't risk that on the kernel stack.
650 */
651
652 static int
653 redo_rank(struct g_geom *gp)
654 {
655 struct g_consumer *cp;
656 struct g_geom *gp1, *gp2;
657 int n, m;
658
659 g_topology_assert();
660 G_VALID_GEOM(gp);
661
662 /* Invalidate this geoms rank and move it to the tail */
663 gp1 = TAILQ_NEXT(gp, geoms);
664 if (gp1 != NULL) {
665 gp->rank = 0;
666 TAILQ_REMOVE(&geoms, gp, geoms);
667 TAILQ_INSERT_TAIL(&geoms, gp, geoms);
668 } else {
669 gp1 = gp;
670 }
671
672 /* re-rank the rest of the sequence */
673 for (; gp1 != NULL; gp1 = gp2) {
674 gp1->rank = 0;
675 m = 1;
676 LIST_FOREACH(cp, &gp1->consumer, consumer) {
677 if (cp->provider == NULL)
678 continue;
679 n = cp->provider->geom->rank;
680 if (n == 0) {
681 m = 0;
682 break;
683 } else if (n >= m)
684 m = n + 1;
685 }
686 gp1->rank = m;
687 gp2 = TAILQ_NEXT(gp1, geoms);
688
689 /* got a rank, moving on */
690 if (m != 0)
691 continue;
692
693 /* no rank to original geom means loop */
694 if (gp == gp1)
695 return (ELOOP);
696
697 /* no rank, put it at the end move on */
698 TAILQ_REMOVE(&geoms, gp1, geoms);
699 TAILQ_INSERT_TAIL(&geoms, gp1, geoms);
700 }
701 return (0);
702 }
703
704 int
705 g_attach(struct g_consumer *cp, struct g_provider *pp)
706 {
707 int error;
708
709 g_topology_assert();
710 G_VALID_CONSUMER(cp);
711 G_VALID_PROVIDER(pp);
712 KASSERT(cp->provider == NULL, ("attach but attached"));
713 cp->provider = pp;
714 LIST_INSERT_HEAD(&pp->consumers, cp, consumers);
715 error = redo_rank(cp->geom);
716 if (error) {
717 LIST_REMOVE(cp, consumers);
718 cp->provider = NULL;
719 redo_rank(cp->geom);
720 }
721 return (error);
722 }
723
724 void
725 g_detach(struct g_consumer *cp)
726 {
727 struct g_provider *pp;
728
729 g_topology_assert();
730 G_VALID_CONSUMER(cp);
731 g_trace(G_T_TOPOLOGY, "g_detach(%p)", cp);
732 KASSERT(cp->provider != NULL, ("detach but not attached"));
733 KASSERT(cp->acr == 0, ("detach but nonzero acr"));
734 KASSERT(cp->acw == 0, ("detach but nonzero acw"));
735 KASSERT(cp->ace == 0, ("detach but nonzero ace"));
736 KASSERT(cp->nstart == cp->nend,
737 ("detach with active requests"));
738 pp = cp->provider;
739 LIST_REMOVE(cp, consumers);
740 cp->provider = NULL;
741 if (pp->geom->flags & G_GEOM_WITHER)
742 g_do_wither();
743 else if (pp->flags & G_PF_WITHER)
744 g_do_wither();
745 redo_rank(cp->geom);
746 }
747
748 /*
749 * g_access()
750 *
751 * Access-check with delta values. The question asked is "can provider
752 * "cp" change the access counters by the relative amounts dc[rwe] ?"
753 */
754
755 int
756 g_access(struct g_consumer *cp, int dcr, int dcw, int dce)
757 {
758 struct g_provider *pp;
759 int pr,pw,pe;
760 int error;
761
762 g_topology_assert();
763 G_VALID_CONSUMER(cp);
764 pp = cp->provider;
765 KASSERT(pp != NULL, ("access but not attached"));
766 G_VALID_PROVIDER(pp);
767
768 g_trace(G_T_ACCESS, "g_access(%p(%s), %d, %d, %d)",
769 cp, pp->name, dcr, dcw, dce);
770
771 KASSERT(cp->acr + dcr >= 0, ("access resulting in negative acr"));
772 KASSERT(cp->acw + dcw >= 0, ("access resulting in negative acw"));
773 KASSERT(cp->ace + dce >= 0, ("access resulting in negative ace"));
774 KASSERT(dcr != 0 || dcw != 0 || dce != 0, ("NOP access request"));
775 KASSERT(pp->geom->access != NULL, ("NULL geom->access"));
776
777 /*
778 * If our class cares about being spoiled, and we have been, we
779 * are probably just ahead of the event telling us that. Fail
780 * now rather than having to unravel this later.
781 */
782 if (cp->geom->spoiled != NULL && cp->spoiled &&
783 (dcr > 0 || dcw > 0 || dce > 0))
784 return (ENXIO);
785
786 /*
787 * Figure out what counts the provider would have had, if this
788 * consumer had (r0w0e0) at this time.
789 */
790 pr = pp->acr - cp->acr;
791 pw = pp->acw - cp->acw;
792 pe = pp->ace - cp->ace;
793
794 g_trace(G_T_ACCESS,
795 "open delta:[r%dw%de%d] old:[r%dw%de%d] provider:[r%dw%de%d] %p(%s)",
796 dcr, dcw, dce,
797 cp->acr, cp->acw, cp->ace,
798 pp->acr, pp->acw, pp->ace,
799 pp, pp->name);
800
801 /* If foot-shooting is enabled, any open on rank#1 is OK */
802 if ((g_debugflags & 16) && pp->geom->rank == 1)
803 ;
804 /* If we try exclusive but already write: fail */
805 else if (dce > 0 && pw > 0)
806 return (EPERM);
807 /* If we try write but already exclusive: fail */
808 else if (dcw > 0 && pe > 0)
809 return (EPERM);
810 /* If we try to open more but provider is error'ed: fail */
811 else if ((dcr > 0 || dcw > 0 || dce > 0) && pp->error != 0)
812 return (pp->error);
813
814 /* Ok then... */
815
816 error = pp->geom->access(pp, dcr, dcw, dce);
817 KASSERT(dcr > 0 || dcw > 0 || dce > 0 || error == 0,
818 ("Geom provider %s::%s failed closing ->access()",
819 pp->geom->class->name, pp->name));
820 if (!error) {
821 /*
822 * If we open first write, spoil any partner consumers.
823 * If we close last write and provider is not errored,
824 * trigger re-taste.
825 */
826 if (pp->acw == 0 && dcw != 0)
827 g_spoil(pp, cp);
828 else if (pp->acw != 0 && pp->acw == -dcw && pp->error == 0 &&
829 !(pp->geom->flags & G_GEOM_WITHER))
830 g_post_event(g_new_provider_event, pp, M_WAITOK,
831 pp, NULL);
832
833 pp->acr += dcr;
834 pp->acw += dcw;
835 pp->ace += dce;
836 cp->acr += dcr;
837 cp->acw += dcw;
838 cp->ace += dce;
839 if (pp->acr != 0 || pp->acw != 0 |