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1/*
2 * Copyright (C) 2011 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-space-map.h"
8#include "dm-space-map-common.h"
9#include "dm-space-map-metadata.h"
10
11#include <linux/list.h>
12#include <linux/slab.h>
13#include <linux/device-mapper.h>
14#include <linux/kernel.h>
15
16#define DM_MSG_PREFIX "space map metadata"
17
18/*----------------------------------------------------------------*/
19
20/*
21 * An edge triggered threshold.
22 */
23struct threshold {
24 bool threshold_set;
25 bool value_set;
26 dm_block_t threshold;
27 dm_block_t current_value;
28 dm_sm_threshold_fn fn;
29 void *context;
30};
31
32static void threshold_init(struct threshold *t)
33{
34 t->threshold_set = false;
35 t->value_set = false;
36}
37
38static void set_threshold(struct threshold *t, dm_block_t value,
39 dm_sm_threshold_fn fn, void *context)
40{
41 t->threshold_set = true;
42 t->threshold = value;
43 t->fn = fn;
44 t->context = context;
45}
46
47static bool below_threshold(struct threshold *t, dm_block_t value)
48{
49 return t->threshold_set && value <= t->threshold;
50}
51
52static bool threshold_already_triggered(struct threshold *t)
53{
54 return t->value_set && below_threshold(t, t->current_value);
55}
56
57static void check_threshold(struct threshold *t, dm_block_t value)
58{
59 if (below_threshold(t, value) &&
60 !threshold_already_triggered(t))
61 t->fn(t->context);
62
63 t->value_set = true;
64 t->current_value = value;
65}
66
67/*----------------------------------------------------------------*/
68
69/*
70 * Space map interface.
71 *
72 * The low level disk format is written using the standard btree and
73 * transaction manager. This means that performing disk operations may
74 * cause us to recurse into the space map in order to allocate new blocks.
75 * For this reason we have a pool of pre-allocated blocks large enough to
76 * service any metadata_ll_disk operation.
77 */
78
79/*
80 * FIXME: we should calculate this based on the size of the device.
81 * Only the metadata space map needs this functionality.
82 */
83#define MAX_RECURSIVE_ALLOCATIONS 1024
84
85enum block_op_type {
86 BOP_INC,
87 BOP_DEC
88};
89
90struct block_op {
91 enum block_op_type type;
92 dm_block_t b;
93 dm_block_t e;
94};
95
96struct bop_ring_buffer {
97 unsigned begin;
98 unsigned end;
99 struct block_op bops[MAX_RECURSIVE_ALLOCATIONS + 1];
100};
101
102static void brb_init(struct bop_ring_buffer *brb)
103{
104 brb->begin = 0;
105 brb->end = 0;
106}
107
108static bool brb_empty(struct bop_ring_buffer *brb)
109{
110 return brb->begin == brb->end;
111}
112
113static unsigned brb_next(struct bop_ring_buffer *brb, unsigned old)
114{
115 unsigned r = old + 1;
116 return r >= ARRAY_SIZE(brb->bops) ? 0 : r;
117}
118
119static int brb_push(struct bop_ring_buffer *brb,
120 enum block_op_type type, dm_block_t b, dm_block_t e)
121{
122 struct block_op *bop;
123 unsigned next = brb_next(brb, brb->end);
124
125 /*
126 * We don't allow the last bop to be filled, this way we can
127 * differentiate between full and empty.
128 */
129 if (next == brb->begin)
130 return -ENOMEM;
131
132 bop = brb->bops + brb->end;
133 bop->type = type;
134 bop->b = b;
135 bop->e = e;
136
137 brb->end = next;
138
139 return 0;
140}
141
142static int brb_peek(struct bop_ring_buffer *brb, struct block_op *result)
143{
144 struct block_op *bop;
145
146 if (brb_empty(brb))
147 return -ENODATA;
148
149 bop = brb->bops + brb->begin;
150 memcpy(result, bop, sizeof(*result));
151 return 0;
152}
153
154static int brb_pop(struct bop_ring_buffer *brb)
155{
156 if (brb_empty(brb))
157 return -ENODATA;
158
159 brb->begin = brb_next(brb, brb->begin);
160
161 return 0;
162}
163
164/*----------------------------------------------------------------*/
165
166struct sm_metadata {
167 struct dm_space_map sm;
168
169 struct ll_disk ll;
170 struct ll_disk old_ll;
171
172 dm_block_t begin;
173
174 unsigned recursion_count;
175 unsigned allocated_this_transaction;
176 struct bop_ring_buffer uncommitted;
177
178 struct threshold threshold;
179};
180
181static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b, dm_block_t e)
182{
183 int r = brb_push(&smm->uncommitted, type, b, e);
184 if (r) {
185 DMERR("too many recursive allocations");
186 return -ENOMEM;
187 }
188
189 return 0;
190}
191
192static int commit_bop(struct sm_metadata *smm, struct block_op *op)
193{
194 int r = 0;
195 int32_t nr_allocations;
196
197 switch (op->type) {
198 case BOP_INC:
199 r = sm_ll_inc(&smm->ll, op->b, op->e, &nr_allocations);
200 break;
201
202 case BOP_DEC:
203 r = sm_ll_dec(&smm->ll, op->b, op->e, &nr_allocations);
204 break;
205 }
206
207 return r;
208}
209
210static void in(struct sm_metadata *smm)
211{
212 smm->recursion_count++;
213}
214
215static int apply_bops(struct sm_metadata *smm)
216{
217 int r = 0;
218
219 while (!brb_empty(&smm->uncommitted)) {
220 struct block_op bop;
221
222 r = brb_peek(&smm->uncommitted, &bop);
223 if (r) {
224 DMERR("bug in bop ring buffer");
225 break;
226 }
227
228 r = commit_bop(smm, &bop);
229 if (r)
230 break;
231
232 brb_pop(&smm->uncommitted);
233 }
234
235 return r;
236}
237
238static int out(struct sm_metadata *smm)
239{
240 int r = 0;
241
242 /*
243 * If we're not recursing then very bad things are happening.
244 */
245 if (!smm->recursion_count) {
246 DMERR("lost track of recursion depth");
247 return -ENOMEM;
248 }
249
250 if (smm->recursion_count == 1)
251 r = apply_bops(smm);
252
253 smm->recursion_count--;
254
255 return r;
256}
257
258/*
259 * When using the out() function above, we often want to combine an error
260 * code for the operation run in the recursive context with that from
261 * out().
262 */
263static int combine_errors(int r1, int r2)
264{
265 return r1 ? r1 : r2;
266}
267
268static int recursing(struct sm_metadata *smm)
269{
270 return smm->recursion_count;
271}
272
273static void sm_metadata_destroy(struct dm_space_map *sm)
274{
275 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
276
277 kfree(smm);
278}
279
280static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
281{
282 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
283
284 *count = smm->ll.nr_blocks;
285
286 return 0;
287}
288
289static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
290{
291 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
292
293 *count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
294 smm->allocated_this_transaction;
295
296 return 0;
297}
298
299static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
300 uint32_t *result)
301{
302 int r;
303 unsigned i;
304 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
305 unsigned adjustment = 0;
306
307 /*
308 * We may have some uncommitted adjustments to add. This list
309 * should always be really short.
310 */
311 for (i = smm->uncommitted.begin;
312 i != smm->uncommitted.end;
313 i = brb_next(&smm->uncommitted, i)) {
314 struct block_op *op = smm->uncommitted.bops + i;
315
316 if (b < op->b || b >= op->e)
317 continue;
318
319 switch (op->type) {
320 case BOP_INC:
321 adjustment++;
322 break;
323
324 case BOP_DEC:
325 adjustment--;
326 break;
327 }
328 }
329
330 r = sm_ll_lookup(&smm->ll, b, result);
331 if (r)
332 return r;
333
334 *result += adjustment;
335
336 return 0;
337}
338
339static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
340 dm_block_t b, int *result)
341{
342 int r, adjustment = 0;
343 unsigned i;
344 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
345 uint32_t rc;
346
347 /*
348 * We may have some uncommitted adjustments to add. This list
349 * should always be really short.
350 */
351 for (i = smm->uncommitted.begin;
352 i != smm->uncommitted.end;
353 i = brb_next(&smm->uncommitted, i)) {
354
355 struct block_op *op = smm->uncommitted.bops + i;
356
357 if (b < op->b || b >= op->e)
358 continue;
359
360 switch (op->type) {
361 case BOP_INC:
362 adjustment++;
363 break;
364
365 case BOP_DEC:
366 adjustment--;
367 break;
368 }
369 }
370
371 if (adjustment > 1) {
372 *result = 1;
373 return 0;
374 }
375
376 r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
377 if (r)
378 return r;
379
380 if (rc == 3)
381 /*
382 * We err on the side of caution, and always return true.
383 */
384 *result = 1;
385 else
386 *result = rc + adjustment > 1;
387
388 return 0;
389}
390
391static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
392 uint32_t count)
393{
394 int r, r2;
395 int32_t nr_allocations;
396 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
397
398 if (smm->recursion_count) {
399 DMERR("cannot recurse set_count()");
400 return -EINVAL;
401 }
402
403 in(smm);
404 r = sm_ll_insert(&smm->ll, b, count, &nr_allocations);
405 r2 = out(smm);
406
407 return combine_errors(r, r2);
408}
409
410static int sm_metadata_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
411{
412 int r, r2 = 0;
413 int32_t nr_allocations;
414 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
415
416 if (recursing(smm)) {
417 r = add_bop(smm, BOP_INC, b, e);
418 if (r)
419 return r;
420 } else {
421 in(smm);
422 r = sm_ll_inc(&smm->ll, b, e, &nr_allocations);
423 r2 = out(smm);
424 }
425
426 return combine_errors(r, r2);
427}
428
429static int sm_metadata_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
430{
431 int r, r2 = 0;
432 int32_t nr_allocations;
433 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
434
435 if (recursing(smm))
436 r = add_bop(smm, BOP_DEC, b, e);
437 else {
438 in(smm);
439 r = sm_ll_dec(&smm->ll, b, e, &nr_allocations);
440 r2 = out(smm);
441 }
442
443 return combine_errors(r, r2);
444}
445
446static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
447{
448 int r, r2 = 0;
449 int32_t nr_allocations;
450 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
451
452 /*
453 * Any block we allocate has to be free in both the old and current ll.
454 */
455 r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, smm->begin, smm->ll.nr_blocks, b);
456 if (r == -ENOSPC) {
457 /*
458 * There's no free block between smm->begin and the end of the metadata device.
459 * We search before smm->begin in case something has been freed.
460 */
461 r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, 0, smm->begin, b);
462 }
463
464 if (r)
465 return r;
466
467 smm->begin = *b + 1;
468
469 if (recursing(smm))
470 r = add_bop(smm, BOP_INC, *b, *b + 1);
471 else {
472 in(smm);
473 r = sm_ll_inc(&smm->ll, *b, *b + 1, &nr_allocations);
474 r2 = out(smm);
475 }
476
477 if (!r)
478 smm->allocated_this_transaction++;
479
480 return combine_errors(r, r2);
481}
482
483static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
484{
485 dm_block_t count;
486 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
487
488 int r = sm_metadata_new_block_(sm, b);
489 if (r) {
490 DMERR_LIMIT("unable to allocate new metadata block");
491 return r;
492 }
493
494 r = sm_metadata_get_nr_free(sm, &count);
495 if (r) {
496 DMERR_LIMIT("couldn't get free block count");
497 return r;
498 }
499
500 check_threshold(&smm->threshold, count);
501
502 return r;
503}
504
505static int sm_metadata_commit(struct dm_space_map *sm)
506{
507 int r;
508 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
509
510 r = sm_ll_commit(&smm->ll);
511 if (r)
512 return r;
513
514 memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
515 smm->allocated_this_transaction = 0;
516
517 return 0;
518}
519
520static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
521 dm_block_t threshold,
522 dm_sm_threshold_fn fn,
523 void *context)
524{
525 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
526
527 set_threshold(&smm->threshold, threshold, fn, context);
528
529 return 0;
530}
531
532static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
533{
534 *result = sizeof(struct disk_sm_root);
535
536 return 0;
537}
538
539static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
540{
541 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
542 struct disk_sm_root root_le;
543
544 root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
545 root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
546 root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
547 root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
548
549 if (max < sizeof(root_le))
550 return -ENOSPC;
551
552 memcpy(where_le, &root_le, sizeof(root_le));
553
554 return 0;
555}
556
557static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks);
558
559static const struct dm_space_map ops = {
560 .destroy = sm_metadata_destroy,
561 .extend = sm_metadata_extend,
562 .get_nr_blocks = sm_metadata_get_nr_blocks,
563 .get_nr_free = sm_metadata_get_nr_free,
564 .get_count = sm_metadata_get_count,
565 .count_is_more_than_one = sm_metadata_count_is_more_than_one,
566 .set_count = sm_metadata_set_count,
567 .inc_blocks = sm_metadata_inc_blocks,
568 .dec_blocks = sm_metadata_dec_blocks,
569 .new_block = sm_metadata_new_block,
570 .commit = sm_metadata_commit,
571 .root_size = sm_metadata_root_size,
572 .copy_root = sm_metadata_copy_root,
573 .register_threshold_callback = sm_metadata_register_threshold_callback
574};
575
576/*----------------------------------------------------------------*/
577
578/*
579 * When a new space map is created that manages its own space. We use
580 * this tiny bootstrap allocator.
581 */
582static void sm_bootstrap_destroy(struct dm_space_map *sm)
583{
584}
585
586static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
587{
588 DMERR("bootstrap doesn't support extend");
589
590 return -EINVAL;
591}
592
593static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
594{
595 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
596
597 *count = smm->ll.nr_blocks;
598
599 return 0;
600}
601
602static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
603{
604 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
605
606 *count = smm->ll.nr_blocks - smm->begin;
607
608 return 0;
609}
610
611static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
612 uint32_t *result)
613{
614 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
615
616 *result = (b < smm->begin) ? 1 : 0;
617
618 return 0;
619}
620
621static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
622 dm_block_t b, int *result)
623{
624 *result = 0;
625
626 return 0;
627}
628
629static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
630 uint32_t count)
631{
632 DMERR("bootstrap doesn't support set_count");
633
634 return -EINVAL;
635}
636
637static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
638{
639 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
640
641 /*
642 * We know the entire device is unused.
643 */
644 if (smm->begin == smm->ll.nr_blocks)
645 return -ENOSPC;
646
647 *b = smm->begin++;
648
649 return 0;
650}
651
652static int sm_bootstrap_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
653{
654 int r;
655 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
656
657 r = add_bop(smm, BOP_INC, b, e);
658 if (r)
659 return r;
660
661 return 0;
662}
663
664static int sm_bootstrap_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
665{
666 int r;
667 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
668
669 r = add_bop(smm, BOP_DEC, b, e);
670 if (r)
671 return r;
672
673 return 0;
674}
675
676static int sm_bootstrap_commit(struct dm_space_map *sm)
677{
678 return 0;
679}
680
681static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
682{
683 DMERR("bootstrap doesn't support root_size");
684
685 return -EINVAL;
686}
687
688static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
689 size_t max)
690{
691 DMERR("bootstrap doesn't support copy_root");
692
693 return -EINVAL;
694}
695
696static const struct dm_space_map bootstrap_ops = {
697 .destroy = sm_bootstrap_destroy,
698 .extend = sm_bootstrap_extend,
699 .get_nr_blocks = sm_bootstrap_get_nr_blocks,
700 .get_nr_free = sm_bootstrap_get_nr_free,
701 .get_count = sm_bootstrap_get_count,
702 .count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
703 .set_count = sm_bootstrap_set_count,
704 .inc_blocks = sm_bootstrap_inc_blocks,
705 .dec_blocks = sm_bootstrap_dec_blocks,
706 .new_block = sm_bootstrap_new_block,
707 .commit = sm_bootstrap_commit,
708 .root_size = sm_bootstrap_root_size,
709 .copy_root = sm_bootstrap_copy_root,
710 .register_threshold_callback = NULL
711};
712
713/*----------------------------------------------------------------*/
714
715static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
716{
717 int r;
718 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
719 dm_block_t old_len = smm->ll.nr_blocks;
720
721 /*
722 * Flick into a mode where all blocks get allocated in the new area.
723 */
724 smm->begin = old_len;
725 memcpy(sm, &bootstrap_ops, sizeof(*sm));
726
727 /*
728 * Extend.
729 */
730 r = sm_ll_extend(&smm->ll, extra_blocks);
731 if (r)
732 goto out;
733
734 /*
735 * We repeatedly increment then commit until the commit doesn't
736 * allocate any new blocks.
737 */
738 do {
739 r = add_bop(smm, BOP_INC, old_len, smm->begin);
740 if (r)
741 goto out;
742
743 old_len = smm->begin;
744
745 r = apply_bops(smm);
746 if (r) {
747 DMERR("%s: apply_bops failed", __func__);
748 goto out;
749 }
750
751 r = sm_ll_commit(&smm->ll);
752 if (r)
753 goto out;
754
755 } while (old_len != smm->begin);
756
757out:
758 /*
759 * Switch back to normal behaviour.
760 */
761 memcpy(sm, &ops, sizeof(*sm));
762 return r;
763}
764
765/*----------------------------------------------------------------*/
766
767struct dm_space_map *dm_sm_metadata_init(void)
768{
769 struct sm_metadata *smm;
770
771 smm = kmalloc(sizeof(*smm), GFP_KERNEL);
772 if (!smm)
773 return ERR_PTR(-ENOMEM);
774
775 memcpy(&smm->sm, &ops, sizeof(smm->sm));
776
777 return &smm->sm;
778}
779
780int dm_sm_metadata_create(struct dm_space_map *sm,
781 struct dm_transaction_manager *tm,
782 dm_block_t nr_blocks,
783 dm_block_t superblock)
784{
785 int r;
786 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
787
788 smm->begin = superblock + 1;
789 smm->recursion_count = 0;
790 smm->allocated_this_transaction = 0;
791 brb_init(&smm->uncommitted);
792 threshold_init(&smm->threshold);
793
794 memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
795
796 r = sm_ll_new_metadata(&smm->ll, tm);
797 if (!r) {
798 if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
799 nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
800 r = sm_ll_extend(&smm->ll, nr_blocks);
801 }
802 memcpy(&smm->sm, &ops, sizeof(smm->sm));
803 if (r)
804 return r;
805
806 /*
807 * Now we need to update the newly created data structures with the
808 * allocated blocks that they were built from.
809 */
810 r = add_bop(smm, BOP_INC, superblock, smm->begin);
811 if (r)
812 return r;
813
814 r = apply_bops(smm);
815 if (r) {
816 DMERR("%s: apply_bops failed", __func__);
817 return r;
818 }
819
820 return sm_metadata_commit(sm);
821}
822
823int dm_sm_metadata_open(struct dm_space_map *sm,
824 struct dm_transaction_manager *tm,
825 void *root_le, size_t len)
826{
827 int r;
828 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
829
830 r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
831 if (r)
832 return r;
833
834 smm->begin = 0;
835 smm->recursion_count = 0;
836 smm->allocated_this_transaction = 0;
837 brb_init(&smm->uncommitted);
838 threshold_init(&smm->threshold);
839
840 memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
841 return 0;
842}
1/*
2 * Copyright (C) 2011 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-space-map.h"
8#include "dm-space-map-common.h"
9#include "dm-space-map-metadata.h"
10
11#include <linux/list.h>
12#include <linux/slab.h>
13#include <linux/device-mapper.h>
14#include <linux/kernel.h>
15
16#define DM_MSG_PREFIX "space map metadata"
17
18/*----------------------------------------------------------------*/
19
20/*
21 * An edge triggered threshold.
22 */
23struct threshold {
24 bool threshold_set;
25 bool value_set;
26 dm_block_t threshold;
27 dm_block_t current_value;
28 dm_sm_threshold_fn fn;
29 void *context;
30};
31
32static void threshold_init(struct threshold *t)
33{
34 t->threshold_set = false;
35 t->value_set = false;
36}
37
38static void set_threshold(struct threshold *t, dm_block_t value,
39 dm_sm_threshold_fn fn, void *context)
40{
41 t->threshold_set = true;
42 t->threshold = value;
43 t->fn = fn;
44 t->context = context;
45}
46
47static bool below_threshold(struct threshold *t, dm_block_t value)
48{
49 return t->threshold_set && value <= t->threshold;
50}
51
52static bool threshold_already_triggered(struct threshold *t)
53{
54 return t->value_set && below_threshold(t, t->current_value);
55}
56
57static void check_threshold(struct threshold *t, dm_block_t value)
58{
59 if (below_threshold(t, value) &&
60 !threshold_already_triggered(t))
61 t->fn(t->context);
62
63 t->value_set = true;
64 t->current_value = value;
65}
66
67/*----------------------------------------------------------------*/
68
69/*
70 * Space map interface.
71 *
72 * The low level disk format is written using the standard btree and
73 * transaction manager. This means that performing disk operations may
74 * cause us to recurse into the space map in order to allocate new blocks.
75 * For this reason we have a pool of pre-allocated blocks large enough to
76 * service any metadata_ll_disk operation.
77 */
78
79/*
80 * FIXME: we should calculate this based on the size of the device.
81 * Only the metadata space map needs this functionality.
82 */
83#define MAX_RECURSIVE_ALLOCATIONS 1024
84
85enum block_op_type {
86 BOP_INC,
87 BOP_DEC
88};
89
90struct block_op {
91 enum block_op_type type;
92 dm_block_t block;
93};
94
95struct bop_ring_buffer {
96 unsigned begin;
97 unsigned end;
98 struct block_op bops[MAX_RECURSIVE_ALLOCATIONS + 1];
99};
100
101static void brb_init(struct bop_ring_buffer *brb)
102{
103 brb->begin = 0;
104 brb->end = 0;
105}
106
107static bool brb_empty(struct bop_ring_buffer *brb)
108{
109 return brb->begin == brb->end;
110}
111
112static unsigned brb_next(struct bop_ring_buffer *brb, unsigned old)
113{
114 unsigned r = old + 1;
115 return r >= ARRAY_SIZE(brb->bops) ? 0 : r;
116}
117
118static int brb_push(struct bop_ring_buffer *brb,
119 enum block_op_type type, dm_block_t b)
120{
121 struct block_op *bop;
122 unsigned next = brb_next(brb, brb->end);
123
124 /*
125 * We don't allow the last bop to be filled, this way we can
126 * differentiate between full and empty.
127 */
128 if (next == brb->begin)
129 return -ENOMEM;
130
131 bop = brb->bops + brb->end;
132 bop->type = type;
133 bop->block = b;
134
135 brb->end = next;
136
137 return 0;
138}
139
140static int brb_peek(struct bop_ring_buffer *brb, struct block_op *result)
141{
142 struct block_op *bop;
143
144 if (brb_empty(brb))
145 return -ENODATA;
146
147 bop = brb->bops + brb->begin;
148 result->type = bop->type;
149 result->block = bop->block;
150
151 return 0;
152}
153
154static int brb_pop(struct bop_ring_buffer *brb)
155{
156 if (brb_empty(brb))
157 return -ENODATA;
158
159 brb->begin = brb_next(brb, brb->begin);
160
161 return 0;
162}
163
164/*----------------------------------------------------------------*/
165
166struct sm_metadata {
167 struct dm_space_map sm;
168
169 struct ll_disk ll;
170 struct ll_disk old_ll;
171
172 dm_block_t begin;
173
174 unsigned recursion_count;
175 unsigned allocated_this_transaction;
176 struct bop_ring_buffer uncommitted;
177
178 struct threshold threshold;
179};
180
181static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
182{
183 int r = brb_push(&smm->uncommitted, type, b);
184
185 if (r) {
186 DMERR("too many recursive allocations");
187 return -ENOMEM;
188 }
189
190 return 0;
191}
192
193static int commit_bop(struct sm_metadata *smm, struct block_op *op)
194{
195 int r = 0;
196 enum allocation_event ev;
197
198 switch (op->type) {
199 case BOP_INC:
200 r = sm_ll_inc(&smm->ll, op->block, &ev);
201 break;
202
203 case BOP_DEC:
204 r = sm_ll_dec(&smm->ll, op->block, &ev);
205 break;
206 }
207
208 return r;
209}
210
211static void in(struct sm_metadata *smm)
212{
213 smm->recursion_count++;
214}
215
216static int apply_bops(struct sm_metadata *smm)
217{
218 int r = 0;
219
220 while (!brb_empty(&smm->uncommitted)) {
221 struct block_op bop;
222
223 r = brb_peek(&smm->uncommitted, &bop);
224 if (r) {
225 DMERR("bug in bop ring buffer");
226 break;
227 }
228
229 r = commit_bop(smm, &bop);
230 if (r)
231 break;
232
233 brb_pop(&smm->uncommitted);
234 }
235
236 return r;
237}
238
239static int out(struct sm_metadata *smm)
240{
241 int r = 0;
242
243 /*
244 * If we're not recursing then very bad things are happening.
245 */
246 if (!smm->recursion_count) {
247 DMERR("lost track of recursion depth");
248 return -ENOMEM;
249 }
250
251 if (smm->recursion_count == 1)
252 r = apply_bops(smm);
253
254 smm->recursion_count--;
255
256 return r;
257}
258
259/*
260 * When using the out() function above, we often want to combine an error
261 * code for the operation run in the recursive context with that from
262 * out().
263 */
264static int combine_errors(int r1, int r2)
265{
266 return r1 ? r1 : r2;
267}
268
269static int recursing(struct sm_metadata *smm)
270{
271 return smm->recursion_count;
272}
273
274static void sm_metadata_destroy(struct dm_space_map *sm)
275{
276 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
277
278 kfree(smm);
279}
280
281static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
282{
283 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
284
285 *count = smm->ll.nr_blocks;
286
287 return 0;
288}
289
290static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
291{
292 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
293
294 *count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
295 smm->allocated_this_transaction;
296
297 return 0;
298}
299
300static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
301 uint32_t *result)
302{
303 int r;
304 unsigned i;
305 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
306 unsigned adjustment = 0;
307
308 /*
309 * We may have some uncommitted adjustments to add. This list
310 * should always be really short.
311 */
312 for (i = smm->uncommitted.begin;
313 i != smm->uncommitted.end;
314 i = brb_next(&smm->uncommitted, i)) {
315 struct block_op *op = smm->uncommitted.bops + i;
316
317 if (op->block != b)
318 continue;
319
320 switch (op->type) {
321 case BOP_INC:
322 adjustment++;
323 break;
324
325 case BOP_DEC:
326 adjustment--;
327 break;
328 }
329 }
330
331 r = sm_ll_lookup(&smm->ll, b, result);
332 if (r)
333 return r;
334
335 *result += adjustment;
336
337 return 0;
338}
339
340static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
341 dm_block_t b, int *result)
342{
343 int r, adjustment = 0;
344 unsigned i;
345 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
346 uint32_t rc;
347
348 /*
349 * We may have some uncommitted adjustments to add. This list
350 * should always be really short.
351 */
352 for (i = smm->uncommitted.begin;
353 i != smm->uncommitted.end;
354 i = brb_next(&smm->uncommitted, i)) {
355
356 struct block_op *op = smm->uncommitted.bops + i;
357
358 if (op->block != b)
359 continue;
360
361 switch (op->type) {
362 case BOP_INC:
363 adjustment++;
364 break;
365
366 case BOP_DEC:
367 adjustment--;
368 break;
369 }
370 }
371
372 if (adjustment > 1) {
373 *result = 1;
374 return 0;
375 }
376
377 r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
378 if (r)
379 return r;
380
381 if (rc == 3)
382 /*
383 * We err on the side of caution, and always return true.
384 */
385 *result = 1;
386 else
387 *result = rc + adjustment > 1;
388
389 return 0;
390}
391
392static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
393 uint32_t count)
394{
395 int r, r2;
396 enum allocation_event ev;
397 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
398
399 if (smm->recursion_count) {
400 DMERR("cannot recurse set_count()");
401 return -EINVAL;
402 }
403
404 in(smm);
405 r = sm_ll_insert(&smm->ll, b, count, &ev);
406 r2 = out(smm);
407
408 return combine_errors(r, r2);
409}
410
411static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b)
412{
413 int r, r2 = 0;
414 enum allocation_event ev;
415 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
416
417 if (recursing(smm))
418 r = add_bop(smm, BOP_INC, b);
419 else {
420 in(smm);
421 r = sm_ll_inc(&smm->ll, b, &ev);
422 r2 = out(smm);
423 }
424
425 return combine_errors(r, r2);
426}
427
428static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b)
429{
430 int r, r2 = 0;
431 enum allocation_event ev;
432 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
433
434 if (recursing(smm))
435 r = add_bop(smm, BOP_DEC, b);
436 else {
437 in(smm);
438 r = sm_ll_dec(&smm->ll, b, &ev);
439 r2 = out(smm);
440 }
441
442 return combine_errors(r, r2);
443}
444
445static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
446{
447 int r, r2 = 0;
448 enum allocation_event ev;
449 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
450
451 /*
452 * Any block we allocate has to be free in both the old and current ll.
453 */
454 r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, smm->begin, smm->ll.nr_blocks, b);
455 if (r)
456 return r;
457
458 smm->begin = *b + 1;
459
460 if (recursing(smm))
461 r = add_bop(smm, BOP_INC, *b);
462 else {
463 in(smm);
464 r = sm_ll_inc(&smm->ll, *b, &ev);
465 r2 = out(smm);
466 }
467
468 if (!r)
469 smm->allocated_this_transaction++;
470
471 return combine_errors(r, r2);
472}
473
474static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
475{
476 dm_block_t count;
477 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
478
479 int r = sm_metadata_new_block_(sm, b);
480 if (r) {
481 DMERR_LIMIT("unable to allocate new metadata block");
482 return r;
483 }
484
485 r = sm_metadata_get_nr_free(sm, &count);
486 if (r) {
487 DMERR_LIMIT("couldn't get free block count");
488 return r;
489 }
490
491 check_threshold(&smm->threshold, count);
492
493 return r;
494}
495
496static int sm_metadata_commit(struct dm_space_map *sm)
497{
498 int r;
499 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
500
501 r = sm_ll_commit(&smm->ll);
502 if (r)
503 return r;
504
505 memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
506 smm->begin = 0;
507 smm->allocated_this_transaction = 0;
508
509 return 0;
510}
511
512static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
513 dm_block_t threshold,
514 dm_sm_threshold_fn fn,
515 void *context)
516{
517 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
518
519 set_threshold(&smm->threshold, threshold, fn, context);
520
521 return 0;
522}
523
524static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
525{
526 *result = sizeof(struct disk_sm_root);
527
528 return 0;
529}
530
531static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
532{
533 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
534 struct disk_sm_root root_le;
535
536 root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
537 root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
538 root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
539 root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
540
541 if (max < sizeof(root_le))
542 return -ENOSPC;
543
544 memcpy(where_le, &root_le, sizeof(root_le));
545
546 return 0;
547}
548
549static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks);
550
551static const struct dm_space_map ops = {
552 .destroy = sm_metadata_destroy,
553 .extend = sm_metadata_extend,
554 .get_nr_blocks = sm_metadata_get_nr_blocks,
555 .get_nr_free = sm_metadata_get_nr_free,
556 .get_count = sm_metadata_get_count,
557 .count_is_more_than_one = sm_metadata_count_is_more_than_one,
558 .set_count = sm_metadata_set_count,
559 .inc_block = sm_metadata_inc_block,
560 .dec_block = sm_metadata_dec_block,
561 .new_block = sm_metadata_new_block,
562 .commit = sm_metadata_commit,
563 .root_size = sm_metadata_root_size,
564 .copy_root = sm_metadata_copy_root,
565 .register_threshold_callback = sm_metadata_register_threshold_callback
566};
567
568/*----------------------------------------------------------------*/
569
570/*
571 * When a new space map is created that manages its own space. We use
572 * this tiny bootstrap allocator.
573 */
574static void sm_bootstrap_destroy(struct dm_space_map *sm)
575{
576}
577
578static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
579{
580 DMERR("bootstrap doesn't support extend");
581
582 return -EINVAL;
583}
584
585static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
586{
587 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
588
589 *count = smm->ll.nr_blocks;
590
591 return 0;
592}
593
594static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
595{
596 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
597
598 *count = smm->ll.nr_blocks - smm->begin;
599
600 return 0;
601}
602
603static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
604 uint32_t *result)
605{
606 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
607
608 *result = (b < smm->begin) ? 1 : 0;
609
610 return 0;
611}
612
613static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
614 dm_block_t b, int *result)
615{
616 *result = 0;
617
618 return 0;
619}
620
621static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
622 uint32_t count)
623{
624 DMERR("bootstrap doesn't support set_count");
625
626 return -EINVAL;
627}
628
629static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
630{
631 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
632
633 /*
634 * We know the entire device is unused.
635 */
636 if (smm->begin == smm->ll.nr_blocks)
637 return -ENOSPC;
638
639 *b = smm->begin++;
640
641 return 0;
642}
643
644static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b)
645{
646 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
647
648 return add_bop(smm, BOP_INC, b);
649}
650
651static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b)
652{
653 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
654
655 return add_bop(smm, BOP_DEC, b);
656}
657
658static int sm_bootstrap_commit(struct dm_space_map *sm)
659{
660 return 0;
661}
662
663static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
664{
665 DMERR("bootstrap doesn't support root_size");
666
667 return -EINVAL;
668}
669
670static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
671 size_t max)
672{
673 DMERR("bootstrap doesn't support copy_root");
674
675 return -EINVAL;
676}
677
678static const struct dm_space_map bootstrap_ops = {
679 .destroy = sm_bootstrap_destroy,
680 .extend = sm_bootstrap_extend,
681 .get_nr_blocks = sm_bootstrap_get_nr_blocks,
682 .get_nr_free = sm_bootstrap_get_nr_free,
683 .get_count = sm_bootstrap_get_count,
684 .count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
685 .set_count = sm_bootstrap_set_count,
686 .inc_block = sm_bootstrap_inc_block,
687 .dec_block = sm_bootstrap_dec_block,
688 .new_block = sm_bootstrap_new_block,
689 .commit = sm_bootstrap_commit,
690 .root_size = sm_bootstrap_root_size,
691 .copy_root = sm_bootstrap_copy_root,
692 .register_threshold_callback = NULL
693};
694
695/*----------------------------------------------------------------*/
696
697static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
698{
699 int r, i;
700 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
701 dm_block_t old_len = smm->ll.nr_blocks;
702
703 /*
704 * Flick into a mode where all blocks get allocated in the new area.
705 */
706 smm->begin = old_len;
707 memcpy(sm, &bootstrap_ops, sizeof(*sm));
708
709 /*
710 * Extend.
711 */
712 r = sm_ll_extend(&smm->ll, extra_blocks);
713 if (r)
714 goto out;
715
716 /*
717 * We repeatedly increment then commit until the commit doesn't
718 * allocate any new blocks.
719 */
720 do {
721 for (i = old_len; !r && i < smm->begin; i++)
722 r = add_bop(smm, BOP_INC, i);
723
724 if (r)
725 goto out;
726
727 old_len = smm->begin;
728
729 r = apply_bops(smm);
730 if (r) {
731 DMERR("%s: apply_bops failed", __func__);
732 goto out;
733 }
734
735 r = sm_ll_commit(&smm->ll);
736 if (r)
737 goto out;
738
739 } while (old_len != smm->begin);
740
741out:
742 /*
743 * Switch back to normal behaviour.
744 */
745 memcpy(sm, &ops, sizeof(*sm));
746 return r;
747}
748
749/*----------------------------------------------------------------*/
750
751struct dm_space_map *dm_sm_metadata_init(void)
752{
753 struct sm_metadata *smm;
754
755 smm = kmalloc(sizeof(*smm), GFP_KERNEL);
756 if (!smm)
757 return ERR_PTR(-ENOMEM);
758
759 memcpy(&smm->sm, &ops, sizeof(smm->sm));
760
761 return &smm->sm;
762}
763
764int dm_sm_metadata_create(struct dm_space_map *sm,
765 struct dm_transaction_manager *tm,
766 dm_block_t nr_blocks,
767 dm_block_t superblock)
768{
769 int r;
770 dm_block_t i;
771 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
772
773 smm->begin = superblock + 1;
774 smm->recursion_count = 0;
775 smm->allocated_this_transaction = 0;
776 brb_init(&smm->uncommitted);
777 threshold_init(&smm->threshold);
778
779 memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
780
781 r = sm_ll_new_metadata(&smm->ll, tm);
782 if (!r) {
783 if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
784 nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
785 r = sm_ll_extend(&smm->ll, nr_blocks);
786 }
787 memcpy(&smm->sm, &ops, sizeof(smm->sm));
788 if (r)
789 return r;
790
791 /*
792 * Now we need to update the newly created data structures with the
793 * allocated blocks that they were built from.
794 */
795 for (i = superblock; !r && i < smm->begin; i++)
796 r = add_bop(smm, BOP_INC, i);
797
798 if (r)
799 return r;
800
801 r = apply_bops(smm);
802 if (r) {
803 DMERR("%s: apply_bops failed", __func__);
804 return r;
805 }
806
807 return sm_metadata_commit(sm);
808}
809
810int dm_sm_metadata_open(struct dm_space_map *sm,
811 struct dm_transaction_manager *tm,
812 void *root_le, size_t len)
813{
814 int r;
815 struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
816
817 r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
818 if (r)
819 return r;
820
821 smm->begin = 0;
822 smm->recursion_count = 0;
823 smm->allocated_this_transaction = 0;
824 brb_init(&smm->uncommitted);
825 threshold_init(&smm->threshold);
826
827 memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
828 return 0;
829}