summaryrefslogtreecommitdiffstats
path: root/sys/geom/geom_subr.c
blob: 98b8f8f4c32af93b42265c8e6cff49b5e6be1d0f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
/*-
 * Copyright (c) 2002 Poul-Henning Kamp
 * Copyright (c) 2002 Networks Associates Technology, Inc.
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
 * and NAI Labs, the Security Research Division of Network Associates, Inc.
 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
 * DARPA CHATS research program.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The names of the authors may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/devicestat.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/bio.h>
#include <sys/sysctl.h>
#include <sys/proc.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/errno.h>
#include <sys/sbuf.h>
#include <geom/geom.h>
#include <geom/geom_int.h>
#include <machine/stdarg.h>

struct class_list_head g_classes = LIST_HEAD_INITIALIZER(g_classes);
static struct g_tailq_head geoms = TAILQ_HEAD_INITIALIZER(geoms);
char *g_wait_event, *g_wait_up, *g_wait_down, *g_wait_sim;


struct g_hh00 {
	struct g_class	*mp;
	int		error;
};

/*
 * This event offers a new class a chance to taste all preexisting providers.
 */
static void
g_load_class(void *arg, int flag)
{
	struct g_hh00 *hh;
	struct g_class *mp2, *mp;
	struct g_geom *gp;
	struct g_provider *pp;

	g_topology_assert();
	if (flag == EV_CANCEL)	/* XXX: can't happen ? */
		return;
	if (g_shutdown)
		return;

	hh = arg;
	mp = hh->mp;
	g_free(hh);
	g_trace(G_T_TOPOLOGY, "g_load_class(%s)", mp->name);
	LIST_FOREACH(mp2, &g_classes, class) {
		KASSERT(mp2 != mp,
		    ("The GEOM class %s already loaded", mp2->name));
		KASSERT(strcmp(mp2->name, mp->name) != 0,
		    ("A GEOM class named %s is already loaded", mp2->name));
	}

	if (mp->init != NULL)
		mp->init(mp);
	LIST_INIT(&mp->geom);
	LIST_INSERT_HEAD(&g_classes, mp, class);
	if (mp->taste == NULL)
		return;
	LIST_FOREACH(mp2, &g_classes, class) {
		if (mp == mp2)
			continue;
		LIST_FOREACH(gp, &mp2->geom, geom) {
			LIST_FOREACH(pp, &gp->provider, provider) {
				mp->taste(mp, pp, 0);
				g_topology_assert();
			}
		}
	}
}

static void
g_unload_class(void *arg, int flag)
{
	struct g_hh00 *hh;
	struct g_class *mp;
	struct g_geom *gp;
	struct g_provider *pp;
	struct g_consumer *cp;
	int error;

	g_topology_assert();
	hh = arg;
	mp = hh->mp;
	g_trace(G_T_TOPOLOGY, "g_unload_class(%s)", mp->name);
	if (mp->destroy_geom == NULL) {
		hh->error = EOPNOTSUPP;
		return;
	}

	/* We refuse to unload if anything is open */
	LIST_FOREACH(gp, &mp->geom, geom) {
		LIST_FOREACH(pp, &gp->provider, provider)
			if (pp->acr || pp->acw || pp->ace) {
				hh->error = EBUSY;
				return;
			}
		LIST_FOREACH(cp, &gp->consumer, consumer)
			if (cp->acr || cp->acw || cp->ace) {
				hh->error = EBUSY;
				return;
			}
	}

	/* Bar new entries */
	mp->taste = NULL;
	mp->config = NULL;

	error = 0;
	LIST_FOREACH(gp, &mp->geom, geom) {
		error = mp->destroy_geom(NULL, mp, gp);
		if (error != 0)
			break;
	}
	if (error == 0) {
		LIST_REMOVE(mp, class);
		if (mp->fini != NULL)
			mp->fini(mp);
	}
	hh->error = error;
	return;
}

int
g_modevent(module_t mod, int type, void *data)
{
	struct g_hh00 *hh;
	int error;
	static int g_ignition;

	if (!g_ignition) {
		g_ignition++;
		g_init();
	}
	hh = g_malloc(sizeof *hh, M_WAITOK | M_ZERO);
	hh->mp = data;
	error = EOPNOTSUPP;
	switch (type) {
	case MOD_LOAD:
		g_trace(G_T_TOPOLOGY, "g_modevent(%s, LOAD)", hh->mp->name);
		g_post_event(g_load_class, hh, M_WAITOK, NULL);
		error = 0;
		break;
	case MOD_UNLOAD:
		g_trace(G_T_TOPOLOGY, "g_modevent(%s, UNLOAD)", hh->mp->name);
		error = g_waitfor_event(g_unload_class, hh, M_WAITOK, NULL);
		if (error == 0)
			error = hh->error;
		g_waitidle();
		KASSERT(LIST_EMPTY(&hh->mp->geom),
		    ("Unloaded class (%s) still has geom", hh->mp->name));
		g_free(hh);
		break;
	}
	return (error);
}

struct g_geom *
g_new_geomf(struct g_class *mp, const char *fmt, ...)
{
	struct g_geom *gp;
	va_list ap;
	struct sbuf *sb;

	g_topology_assert();
	sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
	va_start(ap, fmt);
	sbuf_vprintf(sb, fmt, ap);
	va_end(ap);
	sbuf_finish(sb);
	gp = g_malloc(sizeof *gp, M_WAITOK | M_ZERO);
	gp->name = g_malloc(sbuf_len(sb) + 1, M_WAITOK | M_ZERO);
	gp->class = mp;
	gp->rank = 1;
	LIST_INIT(&gp->consumer);
	LIST_INIT(&gp->provider);
	LIST_INSERT_HEAD(&mp->geom, gp, geom);
	TAILQ_INSERT_HEAD(&geoms, gp, geoms);
	strcpy(gp->name, sbuf_data(sb));
	sbuf_delete(sb);
	return (gp);
}

void
g_destroy_geom(struct g_geom *gp)
{

	g_trace(G_T_TOPOLOGY, "g_destroy_geom(%p(%s))", gp, gp->name);
	g_topology_assert();
	KASSERT(LIST_EMPTY(&gp->consumer),
	    ("g_destroy_geom(%s) with consumer(s) [%p]",
	    gp->name, LIST_FIRST(&gp->consumer)));
	KASSERT(LIST_EMPTY(&gp->provider),
	    ("g_destroy_geom(%s) with provider(s) [%p]",
	    gp->name, LIST_FIRST(&gp->consumer)));
	g_cancel_event(gp);
	LIST_REMOVE(gp, geom);
	TAILQ_REMOVE(&geoms, gp, geoms);
	g_free(gp->name);
	g_free(gp);
}

/*
 * This function is called (repeatedly) until has withered away.
 */
void
g_wither_geom(struct g_geom *gp, int error)
{
	struct g_provider *pp, *pp2;
	struct g_consumer *cp, *cp2;
	static int once_is_enough;

	if (once_is_enough)
		return;
	once_is_enough = 1;
	g_trace(G_T_TOPOLOGY, "g_wither_geom(%p(%s))", gp, gp->name);
	g_topology_assert();
	if (!(gp->flags & G_GEOM_WITHER)) {
		gp->flags |= G_GEOM_WITHER;
		LIST_FOREACH(pp, &gp->provider, provider)
			g_orphan_provider(pp, error);
	}
	for (pp = LIST_FIRST(&gp->provider); pp != NULL; pp = pp2) {
		pp2 = LIST_NEXT(pp, provider);
		if (!LIST_EMPTY(&pp->consumers))
			continue;
		g_destroy_provider(pp);
	}
	for (cp = LIST_FIRST(&gp->consumer); cp != NULL; cp = cp2) {
		cp2 = LIST_NEXT(cp, consumer);
		if (cp->acr || cp->acw || cp->ace)
			continue;
		g_detach(cp);
		g_destroy_consumer(cp);
	}
	if (LIST_EMPTY(&gp->provider) && LIST_EMPTY(&gp->consumer))
		g_destroy_geom(gp);
	once_is_enough = 0;
}

struct g_consumer *
g_new_consumer(struct g_geom *gp)
{
	struct g_consumer *cp;

	g_topology_assert();
	KASSERT(gp->orphan != NULL,
	    ("g_new_consumer on geom(%s) (class %s) without orphan",
	    gp->name, gp->class->name));

	cp = g_malloc(sizeof *cp, M_WAITOK | M_ZERO);
	cp->geom = gp;
	cp->stat = devstat_new_entry(cp, -1, 0, DEVSTAT_ALL_SUPPORTED,
	    DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
	LIST_INSERT_HEAD(&gp->consumer, cp, consumer);
	return(cp);
}

void
g_destroy_consumer(struct g_consumer *cp)
{
	struct g_geom *gp;

	g_trace(G_T_TOPOLOGY, "g_destroy_consumer(%p)", cp);
	g_topology_assert();
	KASSERT (cp->provider == NULL, ("g_destroy_consumer but attached"));
	KASSERT (cp->acr == 0, ("g_destroy_consumer with acr"));
	KASSERT (cp->acw == 0, ("g_destroy_consumer with acw"));
	KASSERT (cp->ace == 0, ("g_destroy_consumer with ace"));
	g_cancel_event(cp);
	gp = cp->geom;
	LIST_REMOVE(cp, consumer);
	devstat_remove_entry(cp->stat);
	g_free(cp);
	if (gp->flags & G_GEOM_WITHER)
		g_wither_geom(gp, 0);
}

static void
g_new_provider_event(void *arg, int flag)
{
	struct g_class *mp;
	struct g_provider *pp;
	struct g_consumer *cp;
	int i;

	g_topology_assert();
	if (flag == EV_CANCEL)
		return;
	if (g_shutdown)
		return;
	pp = arg;
	LIST_FOREACH(mp, &g_classes, class) {
		if (mp->taste == NULL)
			continue;
		i = 1;
		LIST_FOREACH(cp, &pp->consumers, consumers)
			if (cp->geom->class == mp)
				i = 0;
		if (!i)
			continue;
		mp->taste(mp, pp, 0);
		g_topology_assert();
	}
}


struct g_provider *
g_new_providerf(struct g_geom *gp, const char *fmt, ...)
{
	struct g_provider *pp;
	struct sbuf *sb;
	va_list ap;

	g_topology_assert();
	sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
	va_start(ap, fmt);
	sbuf_vprintf(sb, fmt, ap);
	va_end(ap);
	sbuf_finish(sb);
	pp = g_malloc(sizeof *pp + sbuf_len(sb) + 1, M_WAITOK | M_ZERO);
	pp->name = (char *)(pp + 1);
	strcpy(pp->name, sbuf_data(sb));
	sbuf_delete(sb);
	LIST_INIT(&pp->consumers);
	pp->error = ENXIO;
	pp->geom = gp;
	pp->stat = devstat_new_entry(pp, -1, 0, DEVSTAT_ALL_SUPPORTED,
	    DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
	LIST_INSERT_HEAD(&gp->provider, pp, provider);
	g_post_event(g_new_provider_event, pp, M_WAITOK, pp, NULL);
	return (pp);
}

void
g_error_provider(struct g_provider *pp, int error)
{

	pp->error = error;
}

struct g_provider *
g_provider_by_name(char const *arg)
{
	struct g_class *cp;
	struct g_geom *gp;
	struct g_provider *pp;

	LIST_FOREACH(cp, &g_classes, class) {
		LIST_FOREACH(gp, &cp->geom, geom) {
			LIST_FOREACH(pp, &gp->provider, provider) {
				if (!strcmp(arg, pp->name))
					return (pp);
			}
		}
	}
	return (NULL);
}

void
g_destroy_provider(struct g_provider *pp)
{
	struct g_geom *gp;

	g_topology_assert();
	KASSERT(LIST_EMPTY(&pp->consumers),
	    ("g_destroy_provider but attached"));
	KASSERT (pp->acr == 0, ("g_destroy_provider with acr"));
	KASSERT (pp->acw == 0, ("g_destroy_provider with acw"));
	KASSERT (pp->acw == 0, ("g_destroy_provider with ace"));
	g_cancel_event(pp);
	LIST_REMOVE(pp, provider);
	gp = pp->geom;
	devstat_remove_entry(pp->stat);
	g_free(pp);
	if ((gp->flags & G_GEOM_WITHER))
		g_wither_geom(gp, 0);
}

/*
 * We keep the "geoms" list sorted by topological order (== increasing
 * numerical rank) at all times.
 * When an attach is done, the attaching geoms rank is invalidated
 * and it is moved to the tail of the list.
 * All geoms later in the sequence has their ranks reevaluated in
 * sequence.  If we cannot assign rank to a geom because it's
 * prerequisites do not have rank, we move that element to the tail
 * of the sequence with invalid rank as well.
 * At some point we encounter our original geom and if we stil fail
 * to assign it a rank, there must be a loop and we fail back to
 * g_attach() which detach again and calls redo_rank again
 * to fix up the damage.
 * It would be much simpler code wise to do it recursively, but we
 * can't risk that on the kernel stack.
 */

static int
redo_rank(struct g_geom *gp)
{
	struct g_consumer *cp;
	struct g_geom *gp1, *gp2;
	int n, m;

	g_topology_assert();

	/* Invalidate this geoms rank and move it to the tail */
	gp1 = TAILQ_NEXT(gp, geoms);
	if (gp1 != NULL) {
		gp->rank = 0;
		TAILQ_REMOVE(&geoms, gp, geoms);
		TAILQ_INSERT_TAIL(&geoms, gp, geoms);
	} else {
		gp1 = gp;
	}

	/* re-rank the rest of the sequence */
	for (; gp1 != NULL; gp1 = gp2) {
		gp1->rank = 0;
		m = 1;
		LIST_FOREACH(cp, &gp1->consumer, consumer) {
			if (cp->provider == NULL)
				continue;
			n = cp->provider->geom->rank;
			if (n == 0) {
				m = 0;
				break;
			} else if (n >= m)
				m = n + 1;
		}
		gp1->rank = m;
		gp2 = TAILQ_NEXT(gp1, geoms);

		/* got a rank, moving on */
		if (m != 0)
			continue;

		/* no rank to original geom means loop */
		if (gp == gp1) 
			return (ELOOP);

		/* no rank, put it at the end move on */
		TAILQ_REMOVE(&geoms, gp1, geoms);
		TAILQ_INSERT_TAIL(&geoms, gp1, geoms);
	}
	return (0);
}

int
g_attach(struct g_consumer *cp, struct g_provider *pp)
{
	int error;

	g_topology_assert();
	KASSERT(cp->provider == NULL, ("attach but attached"));
	cp->provider = pp;
	LIST_INSERT_HEAD(&pp->consumers, cp, consumers);
	error = redo_rank(cp->geom);
	if (error) {
		LIST_REMOVE(cp, consumers);
		cp->provider = NULL;
		redo_rank(cp->geom);
	}
	return (error);
}

void
g_detach(struct g_consumer *cp)
{
	struct g_provider *pp;

	g_trace(G_T_TOPOLOGY, "g_detach(%p)", cp);
	KASSERT(cp != (void*)0xd0d0d0d0, ("ARGH!"));
	g_topology_assert();
	KASSERT(cp->provider != NULL, ("detach but not attached"));
	KASSERT(cp->acr == 0, ("detach but nonzero acr"));
	KASSERT(cp->acw == 0, ("detach but nonzero acw"));
	KASSERT(cp->ace == 0, ("detach but nonzero ace"));
	KASSERT(cp->nstart == cp->nend,
	    ("detach with active requests"));
	pp = cp->provider;
	LIST_REMOVE(cp, consumers);
	cp->provider = NULL;
	if (pp->geom->flags & G_GEOM_WITHER)
		g_wither_geom(pp->geom, 0);
	redo_rank(cp->geom);
}


/*
 * g_access_abs()
 *
 * Access-check with absolute new values:  Just fall through
 * and use the relative version.
 */
int
g_access_abs(struct g_consumer *cp, int acr, int acw, int ace)
{

	g_topology_assert();
	return(g_access_rel(cp,
		acr - cp->acr,
		acw - cp->acw,
		ace - cp->ace));
}

/*
 * g_access_rel()
 *
 * Access-check with delta values.  The question asked is "can provider
 * "cp" change the access counters by the relative amounts dc[rwe] ?"
 */

int
g_access_rel(struct g_consumer *cp, int dcr, int dcw, int dce)
{
	struct g_provider *pp;
	int pr,pw,pe;
	int error;

	pp = cp->provider;

	g_trace(G_T_ACCESS, "g_access_rel(%p(%s), %d, %d, %d)",
	    cp, pp->name, dcr, dcw, dce);

	g_topology_assert();
	KASSERT(cp->provider != NULL, ("access but not attached"));
	KASSERT(cp->acr + dcr >= 0, ("access resulting in negative acr"));
	KASSERT(cp->acw + dcw >= 0, ("access resulting in negative acw"));
	KASSERT(cp->ace + dce >= 0, ("access resulting in negative ace"));
	KASSERT(pp->geom->access != NULL, ("NULL geom->access"));

	/*
	 * If our class cares about being spoiled, and we have been, we
	 * are probably just ahead of the event telling us that.  Fail
	 * now rather than having to unravel this later.
	 */
	if (cp->geom->spoiled != NULL && cp->spoiled) {
		KASSERT(dcr <= 0, ("spoiled but dcr = %d", dcr));
		KASSERT(dcw <= 0, ("spoiled but dce = %d", dcw));
		KASSERT(dce <= 0, ("spoiled but dcw = %d", dce));
	}

	/*
	 * Figure out what counts the provider would have had, if this
	 * consumer had (r0w0e0) at this time.
	 */
	pr = pp->acr - cp->acr;
	pw = pp->acw - cp->acw;
	pe = pp->ace - cp->ace;

	g_trace(G_T_ACCESS,
    "open delta:[r%dw%de%d] old:[r%dw%de%d] provider:[r%dw%de%d] %p(%s)",
	    dcr, dcw, dce,
	    cp->acr, cp->acw, cp->ace,
	    pp->acr, pp->acw, pp->ace,
	    pp, pp->name);

	/* If foot-shooting is enabled, any open on rank#1 is OK */
	if ((g_debugflags & 16) && pp->geom->rank == 1)
		;
	/* If we try exclusive but already write: fail */
	else if (dce > 0 && pw > 0)
		return (EPERM);
	/* If we try write but already exclusive: fail */
	else if (dcw > 0 && pe > 0)
		return (EPERM);
	/* If we try to open more but provider is error'ed: fail */
	else if ((dcr > 0 || dcw > 0 || dce > 0) && pp->error != 0)
		return (pp->error);

	/* Ok then... */

	error = pp->geom->access(pp, dcr, dcw, dce);
	if (!error) {
		/*
		 * If we open first write, spoil any partner consumers.
		 * If we close last write, trigger re-taste.
		 */
		if (pp->acw == 0 && dcw != 0)
			g_spoil(pp, cp);
		else if (pp->acw != 0 && pp->acw == -dcw && 
		    !(pp->geom->flags & G_GEOM_WITHER))
			g_post_event(g_new_provider_event, pp, M_WAITOK, 
			    pp, NULL);

		pp->acr += dcr;
		pp->acw += dcw;
		pp->ace += dce;
		cp->acr += dcr;
		cp->acw += dcw;
		cp->ace += dce;
	}
	return (error);
}

int
g_handleattr_int(struct bio *bp, const char *attribute, int val)
{

	return (g_handleattr(bp, attribute, &val, sizeof val));
}

int
g_handleattr_off_t(struct bio *bp, const char *attribute, off_t val)
{

	return (g_handleattr(bp, attribute, &val, sizeof val));
}

int
g_handleattr(struct bio *bp, const char *attribute, void *val, int len)
{
	int error;

	if (strcmp(bp->bio_attribute, attribute))
		return (0);
	if (bp->bio_length != len) {
		printf("bio_length %jd len %d -> EFAULT\n",
		    (intmax_t)bp->bio_length, len);
		error = EFAULT;
	} else {
		error = 0;
		bcopy(val, bp->bio_data, len);
		bp->bio_completed = len;
	}
	g_io_deliver(bp, error);
	return (1);
}

int
g_std_access(struct g_provider *pp __unused,
	int dr __unused, int dw __unused, int de __unused)
{

        return (0);
}

void
g_std_done(struct bio *bp)
{
	struct bio *bp2;

	bp2 = bp->bio_parent;
	if (bp2->bio_error == 0)
		bp2->bio_error = bp->bio_error;
	bp2->bio_completed += bp->bio_completed;
	g_destroy_bio(bp);
	bp2->bio_inbed++;
	if (bp2->bio_children == bp2->bio_inbed)
		g_io_deliver(bp2, bp2->bio_error);
}

/* XXX: maybe this is only g_slice_spoiled */

void
g_std_spoiled(struct g_consumer *cp)
{
	struct g_geom *gp;
	struct g_provider *pp;

	g_trace(G_T_TOPOLOGY, "g_std_spoiled(%p)", cp);
	g_topology_assert();
	g_detach(cp);
	gp = cp->geom;
	LIST_FOREACH(pp, &gp->provider, provider)
		g_orphan_provider(pp, ENXIO);
	g_destroy_consumer(cp);
	if (LIST_EMPTY(&gp->provider) && LIST_EMPTY(&gp->consumer))
		g_destroy_geom(gp);
	else
		gp->flags |= G_GEOM_WITHER;
}

/*
 * Spoiling happens when a provider is opened for writing, but consumers
 * which are configured by in-band data are attached (slicers for instance).
 * Since the write might potentially change the in-band data, such consumers
 * need to re-evaluate their existence after the writing session closes.
 * We do this by (offering to) tear them down when the open for write happens
 * in return for a re-taste when it closes again.
 * Together with the fact that such consumers grab an 'e' bit whenever they
 * are open, regardless of mode, this ends up DTRT.
 */

static void
g_spoil_event(void *arg, int flag)
{
	struct g_provider *pp;
	struct g_consumer *cp, *cp2;

	g_topology_assert();
	if (flag == EV_CANCEL)
		return;
	pp = arg;
	for (cp = LIST_FIRST(&pp->consumers); cp != NULL; cp = cp2) {
		cp2 = LIST_NEXT(cp, consumers);
		if (!cp->spoiled)
			continue;
		cp->spoiled = 0;
		if (cp->geom->spoiled == NULL)
			continue;
		cp->geom->spoiled(cp);
		g_topology_assert();
	}
}

void
g_spoil(struct g_provider *pp, struct g_consumer *cp)
{
	struct g_consumer *cp2;

	g_topology_assert();

	LIST_FOREACH(cp2, &pp->consumers, consumers) {
		if (cp2 == cp)
			continue;
/*
		KASSERT(cp2->acr == 0, ("spoiling cp->acr = %d", cp2->acr));
		KASSERT(cp2->acw == 0, ("spoiling cp->acw = %d", cp2->acw));
*/
		KASSERT(cp2->ace == 0, ("spoiling cp->ace = %d", cp2->ace));
		cp2->spoiled++;
	}
	g_post_event(g_spoil_event, pp, M_WAITOK, pp, NULL);
}

int
g_getattr__(const char *attr, struct g_consumer *cp, void *var, int len)
{
	int error, i;

	i = len;
	error = g_io_getattr(attr, cp, &i, var);
	if (error)
		return (error);
	if (i != len)
		return (EINVAL);
	return (0);
}

/*
 * Check if the given pointer is a live object
 */

void
g_sanity(void const *ptr)
{
	struct g_class *mp;
	struct g_geom *gp;
	struct g_consumer *cp;
	struct g_provider *pp;

	if (!(g_debugflags & 0x8))
		return;
	LIST_FOREACH(mp, &g_classes, class) {
		KASSERT(mp != ptr, ("Ptr is live class"));
		LIST_FOREACH(gp, &mp->geom, geom) {
			KASSERT(gp != ptr, ("Ptr is live geom"));
			KASSERT(gp->name != ptr, ("Ptr is live geom's name"));
			LIST_FOREACH(cp, &gp->consumer, consumer) {
				KASSERT(cp != ptr, ("Ptr is live consumer"));
			}
			LIST_FOREACH(pp, &gp->provider, provider) {
				KASSERT(pp != ptr, ("Ptr is live provider"));
			}
		}
	}
}

OpenPOWER on IntegriCloud