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1// SPDX-License-Identifier: GPL-2.0-only
2#include "dm.h"
3#include "persistent-data/dm-transaction-manager.h"
4#include "persistent-data/dm-bitset.h"
5#include "persistent-data/dm-space-map.h"
6
7#include <linux/dm-io.h>
8#include <linux/dm-kcopyd.h>
9#include <linux/init.h>
10#include <linux/mempool.h>
11#include <linux/module.h>
12#include <linux/slab.h>
13#include <linux/vmalloc.h>
14
15#define DM_MSG_PREFIX "era"
16
17#define SUPERBLOCK_LOCATION 0
18#define SUPERBLOCK_MAGIC 2126579579
19#define SUPERBLOCK_CSUM_XOR 146538381
20#define MIN_ERA_VERSION 1
21#define MAX_ERA_VERSION 1
22#define INVALID_WRITESET_ROOT SUPERBLOCK_LOCATION
23#define MIN_BLOCK_SIZE 8
24
25/*----------------------------------------------------------------
26 * Writeset
27 *--------------------------------------------------------------*/
28struct writeset_metadata {
29 uint32_t nr_bits;
30 dm_block_t root;
31};
32
33struct writeset {
34 struct writeset_metadata md;
35
36 /*
37 * An in core copy of the bits to save constantly doing look ups on
38 * disk.
39 */
40 unsigned long *bits;
41};
42
43/*
44 * This does not free off the on disk bitset as this will normally be done
45 * after digesting into the era array.
46 */
47static void writeset_free(struct writeset *ws)
48{
49 vfree(ws->bits);
50}
51
52static int setup_on_disk_bitset(struct dm_disk_bitset *info,
53 unsigned nr_bits, dm_block_t *root)
54{
55 int r;
56
57 r = dm_bitset_empty(info, root);
58 if (r)
59 return r;
60
61 return dm_bitset_resize(info, *root, 0, nr_bits, false, root);
62}
63
64static size_t bitset_size(unsigned nr_bits)
65{
66 return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG);
67}
68
69/*
70 * Allocates memory for the in core bitset.
71 */
72static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks)
73{
74 ws->md.nr_bits = nr_blocks;
75 ws->md.root = INVALID_WRITESET_ROOT;
76 ws->bits = vzalloc(bitset_size(nr_blocks));
77 if (!ws->bits) {
78 DMERR("%s: couldn't allocate in memory bitset", __func__);
79 return -ENOMEM;
80 }
81
82 return 0;
83}
84
85/*
86 * Wipes the in-core bitset, and creates a new on disk bitset.
87 */
88static int writeset_init(struct dm_disk_bitset *info, struct writeset *ws)
89{
90 int r;
91
92 memset(ws->bits, 0, bitset_size(ws->md.nr_bits));
93
94 r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root);
95 if (r) {
96 DMERR("%s: setup_on_disk_bitset failed", __func__);
97 return r;
98 }
99
100 return 0;
101}
102
103static bool writeset_marked(struct writeset *ws, dm_block_t block)
104{
105 return test_bit(block, ws->bits);
106}
107
108static int writeset_marked_on_disk(struct dm_disk_bitset *info,
109 struct writeset_metadata *m, dm_block_t block,
110 bool *result)
111{
112 dm_block_t old = m->root;
113
114 /*
115 * The bitset was flushed when it was archived, so we know there'll
116 * be no change to the root.
117 */
118 int r = dm_bitset_test_bit(info, m->root, block, &m->root, result);
119 if (r) {
120 DMERR("%s: dm_bitset_test_bit failed", __func__);
121 return r;
122 }
123
124 BUG_ON(m->root != old);
125
126 return r;
127}
128
129/*
130 * Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was.
131 */
132static int writeset_test_and_set(struct dm_disk_bitset *info,
133 struct writeset *ws, uint32_t block)
134{
135 int r;
136
137 if (!test_and_set_bit(block, ws->bits)) {
138 r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root);
139 if (r) {
140 /* FIXME: fail mode */
141 return r;
142 }
143
144 return 0;
145 }
146
147 return 1;
148}
149
150/*----------------------------------------------------------------
151 * On disk metadata layout
152 *--------------------------------------------------------------*/
153#define SPACE_MAP_ROOT_SIZE 128
154#define UUID_LEN 16
155
156struct writeset_disk {
157 __le32 nr_bits;
158 __le64 root;
159} __packed;
160
161struct superblock_disk {
162 __le32 csum;
163 __le32 flags;
164 __le64 blocknr;
165
166 __u8 uuid[UUID_LEN];
167 __le64 magic;
168 __le32 version;
169
170 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
171
172 __le32 data_block_size;
173 __le32 metadata_block_size;
174 __le32 nr_blocks;
175
176 __le32 current_era;
177 struct writeset_disk current_writeset;
178
179 /*
180 * Only these two fields are valid within the metadata snapshot.
181 */
182 __le64 writeset_tree_root;
183 __le64 era_array_root;
184
185 __le64 metadata_snap;
186} __packed;
187
188/*----------------------------------------------------------------
189 * Superblock validation
190 *--------------------------------------------------------------*/
191static void sb_prepare_for_write(struct dm_block_validator *v,
192 struct dm_block *b,
193 size_t sb_block_size)
194{
195 struct superblock_disk *disk = dm_block_data(b);
196
197 disk->blocknr = cpu_to_le64(dm_block_location(b));
198 disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags,
199 sb_block_size - sizeof(__le32),
200 SUPERBLOCK_CSUM_XOR));
201}
202
203static int check_metadata_version(struct superblock_disk *disk)
204{
205 uint32_t metadata_version = le32_to_cpu(disk->version);
206 if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) {
207 DMERR("Era metadata version %u found, but only versions between %u and %u supported.",
208 metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION);
209 return -EINVAL;
210 }
211
212 return 0;
213}
214
215static int sb_check(struct dm_block_validator *v,
216 struct dm_block *b,
217 size_t sb_block_size)
218{
219 struct superblock_disk *disk = dm_block_data(b);
220 __le32 csum_le;
221
222 if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) {
223 DMERR("sb_check failed: blocknr %llu: wanted %llu",
224 le64_to_cpu(disk->blocknr),
225 (unsigned long long)dm_block_location(b));
226 return -ENOTBLK;
227 }
228
229 if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) {
230 DMERR("sb_check failed: magic %llu: wanted %llu",
231 le64_to_cpu(disk->magic),
232 (unsigned long long) SUPERBLOCK_MAGIC);
233 return -EILSEQ;
234 }
235
236 csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags,
237 sb_block_size - sizeof(__le32),
238 SUPERBLOCK_CSUM_XOR));
239 if (csum_le != disk->csum) {
240 DMERR("sb_check failed: csum %u: wanted %u",
241 le32_to_cpu(csum_le), le32_to_cpu(disk->csum));
242 return -EILSEQ;
243 }
244
245 return check_metadata_version(disk);
246}
247
248static struct dm_block_validator sb_validator = {
249 .name = "superblock",
250 .prepare_for_write = sb_prepare_for_write,
251 .check = sb_check
252};
253
254/*----------------------------------------------------------------
255 * Low level metadata handling
256 *--------------------------------------------------------------*/
257#define DM_ERA_METADATA_BLOCK_SIZE 4096
258#define ERA_MAX_CONCURRENT_LOCKS 5
259
260struct era_metadata {
261 struct block_device *bdev;
262 struct dm_block_manager *bm;
263 struct dm_space_map *sm;
264 struct dm_transaction_manager *tm;
265
266 dm_block_t block_size;
267 uint32_t nr_blocks;
268
269 uint32_t current_era;
270
271 /*
272 * We preallocate 2 writesets. When an era rolls over we
273 * switch between them. This means the allocation is done at
274 * preresume time, rather than on the io path.
275 */
276 struct writeset writesets[2];
277 struct writeset *current_writeset;
278
279 dm_block_t writeset_tree_root;
280 dm_block_t era_array_root;
281
282 struct dm_disk_bitset bitset_info;
283 struct dm_btree_info writeset_tree_info;
284 struct dm_array_info era_array_info;
285
286 dm_block_t metadata_snap;
287
288 /*
289 * A flag that is set whenever a writeset has been archived.
290 */
291 bool archived_writesets;
292
293 /*
294 * Reading the space map root can fail, so we read it into this
295 * buffer before the superblock is locked and updated.
296 */
297 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
298};
299
300static int superblock_read_lock(struct era_metadata *md,
301 struct dm_block **sblock)
302{
303 return dm_bm_read_lock(md->bm, SUPERBLOCK_LOCATION,
304 &sb_validator, sblock);
305}
306
307static int superblock_lock_zero(struct era_metadata *md,
308 struct dm_block **sblock)
309{
310 return dm_bm_write_lock_zero(md->bm, SUPERBLOCK_LOCATION,
311 &sb_validator, sblock);
312}
313
314static int superblock_lock(struct era_metadata *md,
315 struct dm_block **sblock)
316{
317 return dm_bm_write_lock(md->bm, SUPERBLOCK_LOCATION,
318 &sb_validator, sblock);
319}
320
321/* FIXME: duplication with cache and thin */
322static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
323{
324 int r;
325 unsigned i;
326 struct dm_block *b;
327 __le64 *data_le, zero = cpu_to_le64(0);
328 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
329
330 /*
331 * We can't use a validator here - it may be all zeroes.
332 */
333 r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &b);
334 if (r)
335 return r;
336
337 data_le = dm_block_data(b);
338 *result = true;
339 for (i = 0; i < sb_block_size; i++) {
340 if (data_le[i] != zero) {
341 *result = false;
342 break;
343 }
344 }
345
346 dm_bm_unlock(b);
347
348 return 0;
349}
350
351/*----------------------------------------------------------------*/
352
353static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk)
354{
355 disk->nr_bits = cpu_to_le32(core->nr_bits);
356 disk->root = cpu_to_le64(core->root);
357}
358
359static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core)
360{
361 core->nr_bits = le32_to_cpu(disk->nr_bits);
362 core->root = le64_to_cpu(disk->root);
363}
364
365static void ws_inc(void *context, const void *value)
366{
367 struct era_metadata *md = context;
368 struct writeset_disk ws_d;
369 dm_block_t b;
370
371 memcpy(&ws_d, value, sizeof(ws_d));
372 b = le64_to_cpu(ws_d.root);
373
374 dm_tm_inc(md->tm, b);
375}
376
377static void ws_dec(void *context, const void *value)
378{
379 struct era_metadata *md = context;
380 struct writeset_disk ws_d;
381 dm_block_t b;
382
383 memcpy(&ws_d, value, sizeof(ws_d));
384 b = le64_to_cpu(ws_d.root);
385
386 dm_bitset_del(&md->bitset_info, b);
387}
388
389static int ws_eq(void *context, const void *value1, const void *value2)
390{
391 return !memcmp(value1, value2, sizeof(struct writeset_metadata));
392}
393
394/*----------------------------------------------------------------*/
395
396static void setup_writeset_tree_info(struct era_metadata *md)
397{
398 struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type;
399 md->writeset_tree_info.tm = md->tm;
400 md->writeset_tree_info.levels = 1;
401 vt->context = md;
402 vt->size = sizeof(struct writeset_disk);
403 vt->inc = ws_inc;
404 vt->dec = ws_dec;
405 vt->equal = ws_eq;
406}
407
408static void setup_era_array_info(struct era_metadata *md)
409
410{
411 struct dm_btree_value_type vt;
412 vt.context = NULL;
413 vt.size = sizeof(__le32);
414 vt.inc = NULL;
415 vt.dec = NULL;
416 vt.equal = NULL;
417
418 dm_array_info_init(&md->era_array_info, md->tm, &vt);
419}
420
421static void setup_infos(struct era_metadata *md)
422{
423 dm_disk_bitset_init(md->tm, &md->bitset_info);
424 setup_writeset_tree_info(md);
425 setup_era_array_info(md);
426}
427
428/*----------------------------------------------------------------*/
429
430static int create_fresh_metadata(struct era_metadata *md)
431{
432 int r;
433
434 r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION,
435 &md->tm, &md->sm);
436 if (r < 0) {
437 DMERR("dm_tm_create_with_sm failed");
438 return r;
439 }
440
441 setup_infos(md);
442
443 r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root);
444 if (r) {
445 DMERR("couldn't create new writeset tree");
446 goto bad;
447 }
448
449 r = dm_array_empty(&md->era_array_info, &md->era_array_root);
450 if (r) {
451 DMERR("couldn't create era array");
452 goto bad;
453 }
454
455 return 0;
456
457bad:
458 dm_sm_destroy(md->sm);
459 dm_tm_destroy(md->tm);
460
461 return r;
462}
463
464static int save_sm_root(struct era_metadata *md)
465{
466 int r;
467 size_t metadata_len;
468
469 r = dm_sm_root_size(md->sm, &metadata_len);
470 if (r < 0)
471 return r;
472
473 return dm_sm_copy_root(md->sm, &md->metadata_space_map_root,
474 metadata_len);
475}
476
477static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk)
478{
479 memcpy(&disk->metadata_space_map_root,
480 &md->metadata_space_map_root,
481 sizeof(md->metadata_space_map_root));
482}
483
484/*
485 * Writes a superblock, including the static fields that don't get updated
486 * with every commit (possible optimisation here). 'md' should be fully
487 * constructed when this is called.
488 */
489static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk)
490{
491 disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
492 disk->flags = cpu_to_le32(0ul);
493
494 /* FIXME: can't keep blanking the uuid (uuid is currently unused though) */
495 memset(disk->uuid, 0, sizeof(disk->uuid));
496 disk->version = cpu_to_le32(MAX_ERA_VERSION);
497
498 copy_sm_root(md, disk);
499
500 disk->data_block_size = cpu_to_le32(md->block_size);
501 disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
502 disk->nr_blocks = cpu_to_le32(md->nr_blocks);
503 disk->current_era = cpu_to_le32(md->current_era);
504
505 ws_pack(&md->current_writeset->md, &disk->current_writeset);
506 disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root);
507 disk->era_array_root = cpu_to_le64(md->era_array_root);
508 disk->metadata_snap = cpu_to_le64(md->metadata_snap);
509}
510
511static int write_superblock(struct era_metadata *md)
512{
513 int r;
514 struct dm_block *sblock;
515 struct superblock_disk *disk;
516
517 r = save_sm_root(md);
518 if (r) {
519 DMERR("%s: save_sm_root failed", __func__);
520 return r;
521 }
522
523 r = superblock_lock_zero(md, &sblock);
524 if (r)
525 return r;
526
527 disk = dm_block_data(sblock);
528 prepare_superblock(md, disk);
529
530 return dm_tm_commit(md->tm, sblock);
531}
532
533/*
534 * Assumes block_size and the infos are set.
535 */
536static int format_metadata(struct era_metadata *md)
537{
538 int r;
539
540 r = create_fresh_metadata(md);
541 if (r)
542 return r;
543
544 r = write_superblock(md);
545 if (r) {
546 dm_sm_destroy(md->sm);
547 dm_tm_destroy(md->tm);
548 return r;
549 }
550
551 return 0;
552}
553
554static int open_metadata(struct era_metadata *md)
555{
556 int r;
557 struct dm_block *sblock;
558 struct superblock_disk *disk;
559
560 r = superblock_read_lock(md, &sblock);
561 if (r) {
562 DMERR("couldn't read_lock superblock");
563 return r;
564 }
565
566 disk = dm_block_data(sblock);
567 r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION,
568 disk->metadata_space_map_root,
569 sizeof(disk->metadata_space_map_root),
570 &md->tm, &md->sm);
571 if (r) {
572 DMERR("dm_tm_open_with_sm failed");
573 goto bad;
574 }
575
576 setup_infos(md);
577
578 md->block_size = le32_to_cpu(disk->data_block_size);
579 md->nr_blocks = le32_to_cpu(disk->nr_blocks);
580 md->current_era = le32_to_cpu(disk->current_era);
581
582 md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root);
583 md->era_array_root = le64_to_cpu(disk->era_array_root);
584 md->metadata_snap = le64_to_cpu(disk->metadata_snap);
585 md->archived_writesets = true;
586
587 dm_bm_unlock(sblock);
588
589 return 0;
590
591bad:
592 dm_bm_unlock(sblock);
593 return r;
594}
595
596static int open_or_format_metadata(struct era_metadata *md,
597 bool may_format)
598{
599 int r;
600 bool unformatted = false;
601
602 r = superblock_all_zeroes(md->bm, &unformatted);
603 if (r)
604 return r;
605
606 if (unformatted)
607 return may_format ? format_metadata(md) : -EPERM;
608
609 return open_metadata(md);
610}
611
612static int create_persistent_data_objects(struct era_metadata *md,
613 bool may_format)
614{
615 int r;
616
617 md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE,
618 ERA_MAX_CONCURRENT_LOCKS);
619 if (IS_ERR(md->bm)) {
620 DMERR("could not create block manager");
621 return PTR_ERR(md->bm);
622 }
623
624 r = open_or_format_metadata(md, may_format);
625 if (r)
626 dm_block_manager_destroy(md->bm);
627
628 return r;
629}
630
631static void destroy_persistent_data_objects(struct era_metadata *md)
632{
633 dm_sm_destroy(md->sm);
634 dm_tm_destroy(md->tm);
635 dm_block_manager_destroy(md->bm);
636}
637
638/*
639 * This waits until all era_map threads have picked up the new filter.
640 */
641static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset)
642{
643 rcu_assign_pointer(md->current_writeset, new_writeset);
644 synchronize_rcu();
645}
646
647/*----------------------------------------------------------------
648 * Writesets get 'digested' into the main era array.
649 *
650 * We're using a coroutine here so the worker thread can do the digestion,
651 * thus avoiding synchronisation of the metadata. Digesting a whole
652 * writeset in one go would cause too much latency.
653 *--------------------------------------------------------------*/
654struct digest {
655 uint32_t era;
656 unsigned nr_bits, current_bit;
657 struct writeset_metadata writeset;
658 __le32 value;
659 struct dm_disk_bitset info;
660
661 int (*step)(struct era_metadata *, struct digest *);
662};
663
664static int metadata_digest_lookup_writeset(struct era_metadata *md,
665 struct digest *d);
666
667static int metadata_digest_remove_writeset(struct era_metadata *md,
668 struct digest *d)
669{
670 int r;
671 uint64_t key = d->era;
672
673 r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root,
674 &key, &md->writeset_tree_root);
675 if (r) {
676 DMERR("%s: dm_btree_remove failed", __func__);
677 return r;
678 }
679
680 d->step = metadata_digest_lookup_writeset;
681 return 0;
682}
683
684#define INSERTS_PER_STEP 100
685
686static int metadata_digest_transcribe_writeset(struct era_metadata *md,
687 struct digest *d)
688{
689 int r;
690 bool marked;
691 unsigned b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits);
692
693 for (b = d->current_bit; b < e; b++) {
694 r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked);
695 if (r) {
696 DMERR("%s: writeset_marked_on_disk failed", __func__);
697 return r;
698 }
699
700 if (!marked)
701 continue;
702
703 __dm_bless_for_disk(&d->value);
704 r = dm_array_set_value(&md->era_array_info, md->era_array_root,
705 b, &d->value, &md->era_array_root);
706 if (r) {
707 DMERR("%s: dm_array_set_value failed", __func__);
708 return r;
709 }
710 }
711
712 if (b == d->nr_bits)
713 d->step = metadata_digest_remove_writeset;
714 else
715 d->current_bit = b;
716
717 return 0;
718}
719
720static int metadata_digest_lookup_writeset(struct era_metadata *md,
721 struct digest *d)
722{
723 int r;
724 uint64_t key;
725 struct writeset_disk disk;
726
727 r = dm_btree_find_lowest_key(&md->writeset_tree_info,
728 md->writeset_tree_root, &key);
729 if (r < 0)
730 return r;
731
732 d->era = key;
733
734 r = dm_btree_lookup(&md->writeset_tree_info,
735 md->writeset_tree_root, &key, &disk);
736 if (r) {
737 if (r == -ENODATA) {
738 d->step = NULL;
739 return 0;
740 }
741
742 DMERR("%s: dm_btree_lookup failed", __func__);
743 return r;
744 }
745
746 ws_unpack(&disk, &d->writeset);
747 d->value = cpu_to_le32(key);
748
749 d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks);
750 d->current_bit = 0;
751 d->step = metadata_digest_transcribe_writeset;
752
753 return 0;
754}
755
756static int metadata_digest_start(struct era_metadata *md, struct digest *d)
757{
758 if (d->step)
759 return 0;
760
761 memset(d, 0, sizeof(*d));
762
763 /*
764 * We initialise another bitset info to avoid any caching side
765 * effects with the previous one.
766 */
767 dm_disk_bitset_init(md->tm, &d->info);
768 d->step = metadata_digest_lookup_writeset;
769
770 return 0;
771}
772
773/*----------------------------------------------------------------
774 * High level metadata interface. Target methods should use these, and not
775 * the lower level ones.
776 *--------------------------------------------------------------*/
777static struct era_metadata *metadata_open(struct block_device *bdev,
778 sector_t block_size,
779 bool may_format)
780{
781 int r;
782 struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL);
783
784 if (!md)
785 return NULL;
786
787 md->bdev = bdev;
788 md->block_size = block_size;
789
790 md->writesets[0].md.root = INVALID_WRITESET_ROOT;
791 md->writesets[1].md.root = INVALID_WRITESET_ROOT;
792 md->current_writeset = &md->writesets[0];
793
794 r = create_persistent_data_objects(md, may_format);
795 if (r) {
796 kfree(md);
797 return ERR_PTR(r);
798 }
799
800 return md;
801}
802
803static void metadata_close(struct era_metadata *md)
804{
805 destroy_persistent_data_objects(md);
806 kfree(md);
807}
808
809static bool valid_nr_blocks(dm_block_t n)
810{
811 /*
812 * dm_bitset restricts us to 2^32. test_bit & co. restrict us
813 * further to 2^31 - 1
814 */
815 return n < (1ull << 31);
816}
817
818static int metadata_resize(struct era_metadata *md, void *arg)
819{
820 int r;
821 dm_block_t *new_size = arg;
822 __le32 value;
823
824 if (!valid_nr_blocks(*new_size)) {
825 DMERR("Invalid number of origin blocks %llu",
826 (unsigned long long) *new_size);
827 return -EINVAL;
828 }
829
830 writeset_free(&md->writesets[0]);
831 writeset_free(&md->writesets[1]);
832
833 r = writeset_alloc(&md->writesets[0], *new_size);
834 if (r) {
835 DMERR("%s: writeset_alloc failed for writeset 0", __func__);
836 return r;
837 }
838
839 r = writeset_alloc(&md->writesets[1], *new_size);
840 if (r) {
841 DMERR("%s: writeset_alloc failed for writeset 1", __func__);
842 return r;
843 }
844
845 value = cpu_to_le32(0u);
846 __dm_bless_for_disk(&value);
847 r = dm_array_resize(&md->era_array_info, md->era_array_root,
848 md->nr_blocks, *new_size,
849 &value, &md->era_array_root);
850 if (r) {
851 DMERR("%s: dm_array_resize failed", __func__);
852 return r;
853 }
854
855 md->nr_blocks = *new_size;
856 return 0;
857}
858
859static int metadata_era_archive(struct era_metadata *md)
860{
861 int r;
862 uint64_t keys[1];
863 struct writeset_disk value;
864
865 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
866 &md->current_writeset->md.root);
867 if (r) {
868 DMERR("%s: dm_bitset_flush failed", __func__);
869 return r;
870 }
871
872 ws_pack(&md->current_writeset->md, &value);
873 md->current_writeset->md.root = INVALID_WRITESET_ROOT;
874
875 keys[0] = md->current_era;
876 __dm_bless_for_disk(&value);
877 r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root,
878 keys, &value, &md->writeset_tree_root);
879 if (r) {
880 DMERR("%s: couldn't insert writeset into btree", __func__);
881 /* FIXME: fail mode */
882 return r;
883 }
884
885 md->archived_writesets = true;
886
887 return 0;
888}
889
890static struct writeset *next_writeset(struct era_metadata *md)
891{
892 return (md->current_writeset == &md->writesets[0]) ?
893 &md->writesets[1] : &md->writesets[0];
894}
895
896static int metadata_new_era(struct era_metadata *md)
897{
898 int r;
899 struct writeset *new_writeset = next_writeset(md);
900
901 r = writeset_init(&md->bitset_info, new_writeset);
902 if (r) {
903 DMERR("%s: writeset_init failed", __func__);
904 return r;
905 }
906
907 swap_writeset(md, new_writeset);
908 md->current_era++;
909
910 return 0;
911}
912
913static int metadata_era_rollover(struct era_metadata *md)
914{
915 int r;
916
917 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
918 r = metadata_era_archive(md);
919 if (r) {
920 DMERR("%s: metadata_archive_era failed", __func__);
921 /* FIXME: fail mode? */
922 return r;
923 }
924 }
925
926 r = metadata_new_era(md);
927 if (r) {
928 DMERR("%s: new era failed", __func__);
929 /* FIXME: fail mode */
930 return r;
931 }
932
933 return 0;
934}
935
936static bool metadata_current_marked(struct era_metadata *md, dm_block_t block)
937{
938 bool r;
939 struct writeset *ws;
940
941 rcu_read_lock();
942 ws = rcu_dereference(md->current_writeset);
943 r = writeset_marked(ws, block);
944 rcu_read_unlock();
945
946 return r;
947}
948
949static int metadata_commit(struct era_metadata *md)
950{
951 int r;
952 struct dm_block *sblock;
953
954 if (md->current_writeset->md.root != SUPERBLOCK_LOCATION) {
955 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
956 &md->current_writeset->md.root);
957 if (r) {
958 DMERR("%s: bitset flush failed", __func__);
959 return r;
960 }
961 }
962
963 r = dm_tm_pre_commit(md->tm);
964 if (r) {
965 DMERR("%s: pre commit failed", __func__);
966 return r;
967 }
968
969 r = save_sm_root(md);
970 if (r) {
971 DMERR("%s: save_sm_root failed", __func__);
972 return r;
973 }
974
975 r = superblock_lock(md, &sblock);
976 if (r) {
977 DMERR("%s: superblock lock failed", __func__);
978 return r;
979 }
980
981 prepare_superblock(md, dm_block_data(sblock));
982
983 return dm_tm_commit(md->tm, sblock);
984}
985
986static int metadata_checkpoint(struct era_metadata *md)
987{
988 /*
989 * For now we just rollover, but later I want to put a check in to
990 * avoid this if the filter is still pretty fresh.
991 */
992 return metadata_era_rollover(md);
993}
994
995/*
996 * Metadata snapshots allow userland to access era data.
997 */
998static int metadata_take_snap(struct era_metadata *md)
999{
1000 int r, inc;
1001 struct dm_block *clone;
1002
1003 if (md->metadata_snap != SUPERBLOCK_LOCATION) {
1004 DMERR("%s: metadata snapshot already exists", __func__);
1005 return -EINVAL;
1006 }
1007
1008 r = metadata_era_rollover(md);
1009 if (r) {
1010 DMERR("%s: era rollover failed", __func__);
1011 return r;
1012 }
1013
1014 r = metadata_commit(md);
1015 if (r) {
1016 DMERR("%s: pre commit failed", __func__);
1017 return r;
1018 }
1019
1020 r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION);
1021 if (r) {
1022 DMERR("%s: couldn't increment superblock", __func__);
1023 return r;
1024 }
1025
1026 r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION,
1027 &sb_validator, &clone, &inc);
1028 if (r) {
1029 DMERR("%s: couldn't shadow superblock", __func__);
1030 dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION);
1031 return r;
1032 }
1033 BUG_ON(!inc);
1034
1035 r = dm_sm_inc_block(md->sm, md->writeset_tree_root);
1036 if (r) {
1037 DMERR("%s: couldn't inc writeset tree root", __func__);
1038 dm_tm_unlock(md->tm, clone);
1039 return r;
1040 }
1041
1042 r = dm_sm_inc_block(md->sm, md->era_array_root);
1043 if (r) {
1044 DMERR("%s: couldn't inc era tree root", __func__);
1045 dm_sm_dec_block(md->sm, md->writeset_tree_root);
1046 dm_tm_unlock(md->tm, clone);
1047 return r;
1048 }
1049
1050 md->metadata_snap = dm_block_location(clone);
1051
1052 dm_tm_unlock(md->tm, clone);
1053
1054 return 0;
1055}
1056
1057static int metadata_drop_snap(struct era_metadata *md)
1058{
1059 int r;
1060 dm_block_t location;
1061 struct dm_block *clone;
1062 struct superblock_disk *disk;
1063
1064 if (md->metadata_snap == SUPERBLOCK_LOCATION) {
1065 DMERR("%s: no snap to drop", __func__);
1066 return -EINVAL;
1067 }
1068
1069 r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone);
1070 if (r) {
1071 DMERR("%s: couldn't read lock superblock clone", __func__);
1072 return r;
1073 }
1074
1075 /*
1076 * Whatever happens now we'll commit with no record of the metadata
1077 * snap.
1078 */
1079 md->metadata_snap = SUPERBLOCK_LOCATION;
1080
1081 disk = dm_block_data(clone);
1082 r = dm_btree_del(&md->writeset_tree_info,
1083 le64_to_cpu(disk->writeset_tree_root));
1084 if (r) {
1085 DMERR("%s: error deleting writeset tree clone", __func__);
1086 dm_tm_unlock(md->tm, clone);
1087 return r;
1088 }
1089
1090 r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root));
1091 if (r) {
1092 DMERR("%s: error deleting era array clone", __func__);
1093 dm_tm_unlock(md->tm, clone);
1094 return r;
1095 }
1096
1097 location = dm_block_location(clone);
1098 dm_tm_unlock(md->tm, clone);
1099
1100 return dm_sm_dec_block(md->sm, location);
1101}
1102
1103struct metadata_stats {
1104 dm_block_t used;
1105 dm_block_t total;
1106 dm_block_t snap;
1107 uint32_t era;
1108};
1109
1110static int metadata_get_stats(struct era_metadata *md, void *ptr)
1111{
1112 int r;
1113 struct metadata_stats *s = ptr;
1114 dm_block_t nr_free, nr_total;
1115
1116 r = dm_sm_get_nr_free(md->sm, &nr_free);
1117 if (r) {
1118 DMERR("dm_sm_get_nr_free returned %d", r);
1119 return r;
1120 }
1121
1122 r = dm_sm_get_nr_blocks(md->sm, &nr_total);
1123 if (r) {
1124 DMERR("dm_pool_get_metadata_dev_size returned %d", r);
1125 return r;
1126 }
1127
1128 s->used = nr_total - nr_free;
1129 s->total = nr_total;
1130 s->snap = md->metadata_snap;
1131 s->era = md->current_era;
1132
1133 return 0;
1134}
1135
1136/*----------------------------------------------------------------*/
1137
1138struct era {
1139 struct dm_target *ti;
1140
1141 struct dm_dev *metadata_dev;
1142 struct dm_dev *origin_dev;
1143
1144 dm_block_t nr_blocks;
1145 uint32_t sectors_per_block;
1146 int sectors_per_block_shift;
1147 struct era_metadata *md;
1148
1149 struct workqueue_struct *wq;
1150 struct work_struct worker;
1151
1152 spinlock_t deferred_lock;
1153 struct bio_list deferred_bios;
1154
1155 spinlock_t rpc_lock;
1156 struct list_head rpc_calls;
1157
1158 struct digest digest;
1159 atomic_t suspended;
1160};
1161
1162struct rpc {
1163 struct list_head list;
1164
1165 int (*fn0)(struct era_metadata *);
1166 int (*fn1)(struct era_metadata *, void *);
1167 void *arg;
1168 int result;
1169
1170 struct completion complete;
1171};
1172
1173/*----------------------------------------------------------------
1174 * Remapping.
1175 *---------------------------------------------------------------*/
1176static bool block_size_is_power_of_two(struct era *era)
1177{
1178 return era->sectors_per_block_shift >= 0;
1179}
1180
1181static dm_block_t get_block(struct era *era, struct bio *bio)
1182{
1183 sector_t block_nr = bio->bi_iter.bi_sector;
1184
1185 if (!block_size_is_power_of_two(era))
1186 (void) sector_div(block_nr, era->sectors_per_block);
1187 else
1188 block_nr >>= era->sectors_per_block_shift;
1189
1190 return block_nr;
1191}
1192
1193static void remap_to_origin(struct era *era, struct bio *bio)
1194{
1195 bio_set_dev(bio, era->origin_dev->bdev);
1196}
1197
1198/*----------------------------------------------------------------
1199 * Worker thread
1200 *--------------------------------------------------------------*/
1201static void wake_worker(struct era *era)
1202{
1203 if (!atomic_read(&era->suspended))
1204 queue_work(era->wq, &era->worker);
1205}
1206
1207static void process_old_eras(struct era *era)
1208{
1209 int r;
1210
1211 if (!era->digest.step)
1212 return;
1213
1214 r = era->digest.step(era->md, &era->digest);
1215 if (r < 0) {
1216 DMERR("%s: digest step failed, stopping digestion", __func__);
1217 era->digest.step = NULL;
1218
1219 } else if (era->digest.step)
1220 wake_worker(era);
1221}
1222
1223static void process_deferred_bios(struct era *era)
1224{
1225 int r;
1226 struct bio_list deferred_bios, marked_bios;
1227 struct bio *bio;
1228 bool commit_needed = false;
1229 bool failed = false;
1230
1231 bio_list_init(&deferred_bios);
1232 bio_list_init(&marked_bios);
1233
1234 spin_lock(&era->deferred_lock);
1235 bio_list_merge(&deferred_bios, &era->deferred_bios);
1236 bio_list_init(&era->deferred_bios);
1237 spin_unlock(&era->deferred_lock);
1238
1239 while ((bio = bio_list_pop(&deferred_bios))) {
1240 r = writeset_test_and_set(&era->md->bitset_info,
1241 era->md->current_writeset,
1242 get_block(era, bio));
1243 if (r < 0) {
1244 /*
1245 * This is bad news, we need to rollback.
1246 * FIXME: finish.
1247 */
1248 failed = true;
1249
1250 } else if (r == 0)
1251 commit_needed = true;
1252
1253 bio_list_add(&marked_bios, bio);
1254 }
1255
1256 if (commit_needed) {
1257 r = metadata_commit(era->md);
1258 if (r)
1259 failed = true;
1260 }
1261
1262 if (failed)
1263 while ((bio = bio_list_pop(&marked_bios)))
1264 bio_io_error(bio);
1265 else
1266 while ((bio = bio_list_pop(&marked_bios)))
1267 submit_bio_noacct(bio);
1268}
1269
1270static void process_rpc_calls(struct era *era)
1271{
1272 int r;
1273 bool need_commit = false;
1274 struct list_head calls;
1275 struct rpc *rpc, *tmp;
1276
1277 INIT_LIST_HEAD(&calls);
1278 spin_lock(&era->rpc_lock);
1279 list_splice_init(&era->rpc_calls, &calls);
1280 spin_unlock(&era->rpc_lock);
1281
1282 list_for_each_entry_safe(rpc, tmp, &calls, list) {
1283 rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg);
1284 need_commit = true;
1285 }
1286
1287 if (need_commit) {
1288 r = metadata_commit(era->md);
1289 if (r)
1290 list_for_each_entry_safe(rpc, tmp, &calls, list)
1291 rpc->result = r;
1292 }
1293
1294 list_for_each_entry_safe(rpc, tmp, &calls, list)
1295 complete(&rpc->complete);
1296}
1297
1298static void kick_off_digest(struct era *era)
1299{
1300 if (era->md->archived_writesets) {
1301 era->md->archived_writesets = false;
1302 metadata_digest_start(era->md, &era->digest);
1303 }
1304}
1305
1306static void do_work(struct work_struct *ws)
1307{
1308 struct era *era = container_of(ws, struct era, worker);
1309
1310 kick_off_digest(era);
1311 process_old_eras(era);
1312 process_deferred_bios(era);
1313 process_rpc_calls(era);
1314}
1315
1316static void defer_bio(struct era *era, struct bio *bio)
1317{
1318 spin_lock(&era->deferred_lock);
1319 bio_list_add(&era->deferred_bios, bio);
1320 spin_unlock(&era->deferred_lock);
1321
1322 wake_worker(era);
1323}
1324
1325/*
1326 * Make an rpc call to the worker to change the metadata.
1327 */
1328static int perform_rpc(struct era *era, struct rpc *rpc)
1329{
1330 rpc->result = 0;
1331 init_completion(&rpc->complete);
1332
1333 spin_lock(&era->rpc_lock);
1334 list_add(&rpc->list, &era->rpc_calls);
1335 spin_unlock(&era->rpc_lock);
1336
1337 wake_worker(era);
1338 wait_for_completion(&rpc->complete);
1339
1340 return rpc->result;
1341}
1342
1343static int in_worker0(struct era *era, int (*fn)(struct era_metadata *))
1344{
1345 struct rpc rpc;
1346 rpc.fn0 = fn;
1347 rpc.fn1 = NULL;
1348
1349 return perform_rpc(era, &rpc);
1350}
1351
1352static int in_worker1(struct era *era,
1353 int (*fn)(struct era_metadata *, void *), void *arg)
1354{
1355 struct rpc rpc;
1356 rpc.fn0 = NULL;
1357 rpc.fn1 = fn;
1358 rpc.arg = arg;
1359
1360 return perform_rpc(era, &rpc);
1361}
1362
1363static void start_worker(struct era *era)
1364{
1365 atomic_set(&era->suspended, 0);
1366}
1367
1368static void stop_worker(struct era *era)
1369{
1370 atomic_set(&era->suspended, 1);
1371 flush_workqueue(era->wq);
1372}
1373
1374/*----------------------------------------------------------------
1375 * Target methods
1376 *--------------------------------------------------------------*/
1377static void era_destroy(struct era *era)
1378{
1379 if (era->md)
1380 metadata_close(era->md);
1381
1382 if (era->wq)
1383 destroy_workqueue(era->wq);
1384
1385 if (era->origin_dev)
1386 dm_put_device(era->ti, era->origin_dev);
1387
1388 if (era->metadata_dev)
1389 dm_put_device(era->ti, era->metadata_dev);
1390
1391 kfree(era);
1392}
1393
1394static dm_block_t calc_nr_blocks(struct era *era)
1395{
1396 return dm_sector_div_up(era->ti->len, era->sectors_per_block);
1397}
1398
1399static bool valid_block_size(dm_block_t block_size)
1400{
1401 bool greater_than_zero = block_size > 0;
1402 bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0;
1403
1404 return greater_than_zero && multiple_of_min_block_size;
1405}
1406
1407/*
1408 * <metadata dev> <data dev> <data block size (sectors)>
1409 */
1410static int era_ctr(struct dm_target *ti, unsigned argc, char **argv)
1411{
1412 int r;
1413 char dummy;
1414 struct era *era;
1415 struct era_metadata *md;
1416
1417 if (argc != 3) {
1418 ti->error = "Invalid argument count";
1419 return -EINVAL;
1420 }
1421
1422 era = kzalloc(sizeof(*era), GFP_KERNEL);
1423 if (!era) {
1424 ti->error = "Error allocating era structure";
1425 return -ENOMEM;
1426 }
1427
1428 era->ti = ti;
1429
1430 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &era->metadata_dev);
1431 if (r) {
1432 ti->error = "Error opening metadata device";
1433 era_destroy(era);
1434 return -EINVAL;
1435 }
1436
1437 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &era->origin_dev);
1438 if (r) {
1439 ti->error = "Error opening data device";
1440 era_destroy(era);
1441 return -EINVAL;
1442 }
1443
1444 r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy);
1445 if (r != 1) {
1446 ti->error = "Error parsing block size";
1447 era_destroy(era);
1448 return -EINVAL;
1449 }
1450
1451 r = dm_set_target_max_io_len(ti, era->sectors_per_block);
1452 if (r) {
1453 ti->error = "could not set max io len";
1454 era_destroy(era);
1455 return -EINVAL;
1456 }
1457
1458 if (!valid_block_size(era->sectors_per_block)) {
1459 ti->error = "Invalid block size";
1460 era_destroy(era);
1461 return -EINVAL;
1462 }
1463 if (era->sectors_per_block & (era->sectors_per_block - 1))
1464 era->sectors_per_block_shift = -1;
1465 else
1466 era->sectors_per_block_shift = __ffs(era->sectors_per_block);
1467
1468 md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true);
1469 if (IS_ERR(md)) {
1470 ti->error = "Error reading metadata";
1471 era_destroy(era);
1472 return PTR_ERR(md);
1473 }
1474 era->md = md;
1475
1476 era->nr_blocks = calc_nr_blocks(era);
1477
1478 r = metadata_resize(era->md, &era->nr_blocks);
1479 if (r) {
1480 ti->error = "couldn't resize metadata";
1481 era_destroy(era);
1482 return -ENOMEM;
1483 }
1484
1485 era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1486 if (!era->wq) {
1487 ti->error = "could not create workqueue for metadata object";
1488 era_destroy(era);
1489 return -ENOMEM;
1490 }
1491 INIT_WORK(&era->worker, do_work);
1492
1493 spin_lock_init(&era->deferred_lock);
1494 bio_list_init(&era->deferred_bios);
1495
1496 spin_lock_init(&era->rpc_lock);
1497 INIT_LIST_HEAD(&era->rpc_calls);
1498
1499 ti->private = era;
1500 ti->num_flush_bios = 1;
1501 ti->flush_supported = true;
1502
1503 ti->num_discard_bios = 1;
1504
1505 return 0;
1506}
1507
1508static void era_dtr(struct dm_target *ti)
1509{
1510 era_destroy(ti->private);
1511}
1512
1513static int era_map(struct dm_target *ti, struct bio *bio)
1514{
1515 struct era *era = ti->private;
1516 dm_block_t block = get_block(era, bio);
1517
1518 /*
1519 * All bios get remapped to the origin device. We do this now, but
1520 * it may not get issued until later. Depending on whether the
1521 * block is marked in this era.
1522 */
1523 remap_to_origin(era, bio);
1524
1525 /*
1526 * REQ_PREFLUSH bios carry no data, so we're not interested in them.
1527 */
1528 if (!(bio->bi_opf & REQ_PREFLUSH) &&
1529 (bio_data_dir(bio) == WRITE) &&
1530 !metadata_current_marked(era->md, block)) {
1531 defer_bio(era, bio);
1532 return DM_MAPIO_SUBMITTED;
1533 }
1534
1535 return DM_MAPIO_REMAPPED;
1536}
1537
1538static void era_postsuspend(struct dm_target *ti)
1539{
1540 int r;
1541 struct era *era = ti->private;
1542
1543 r = in_worker0(era, metadata_era_archive);
1544 if (r) {
1545 DMERR("%s: couldn't archive current era", __func__);
1546 /* FIXME: fail mode */
1547 }
1548
1549 stop_worker(era);
1550}
1551
1552static int era_preresume(struct dm_target *ti)
1553{
1554 int r;
1555 struct era *era = ti->private;
1556 dm_block_t new_size = calc_nr_blocks(era);
1557
1558 if (era->nr_blocks != new_size) {
1559 r = in_worker1(era, metadata_resize, &new_size);
1560 if (r)
1561 return r;
1562
1563 era->nr_blocks = new_size;
1564 }
1565
1566 start_worker(era);
1567
1568 r = in_worker0(era, metadata_new_era);
1569 if (r) {
1570 DMERR("%s: metadata_era_rollover failed", __func__);
1571 return r;
1572 }
1573
1574 return 0;
1575}
1576
1577/*
1578 * Status format:
1579 *
1580 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
1581 * <current era> <held metadata root | '-'>
1582 */
1583static void era_status(struct dm_target *ti, status_type_t type,
1584 unsigned status_flags, char *result, unsigned maxlen)
1585{
1586 int r;
1587 struct era *era = ti->private;
1588 ssize_t sz = 0;
1589 struct metadata_stats stats;
1590 char buf[BDEVNAME_SIZE];
1591
1592 switch (type) {
1593 case STATUSTYPE_INFO:
1594 r = in_worker1(era, metadata_get_stats, &stats);
1595 if (r)
1596 goto err;
1597
1598 DMEMIT("%u %llu/%llu %u",
1599 (unsigned) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
1600 (unsigned long long) stats.used,
1601 (unsigned long long) stats.total,
1602 (unsigned) stats.era);
1603
1604 if (stats.snap != SUPERBLOCK_LOCATION)
1605 DMEMIT(" %llu", stats.snap);
1606 else
1607 DMEMIT(" -");
1608 break;
1609
1610 case STATUSTYPE_TABLE:
1611 format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
1612 DMEMIT("%s ", buf);
1613 format_dev_t(buf, era->origin_dev->bdev->bd_dev);
1614 DMEMIT("%s %u", buf, era->sectors_per_block);
1615 break;
1616 }
1617
1618 return;
1619
1620err:
1621 DMEMIT("Error");
1622}
1623
1624static int era_message(struct dm_target *ti, unsigned argc, char **argv,
1625 char *result, unsigned maxlen)
1626{
1627 struct era *era = ti->private;
1628
1629 if (argc != 1) {
1630 DMERR("incorrect number of message arguments");
1631 return -EINVAL;
1632 }
1633
1634 if (!strcasecmp(argv[0], "checkpoint"))
1635 return in_worker0(era, metadata_checkpoint);
1636
1637 if (!strcasecmp(argv[0], "take_metadata_snap"))
1638 return in_worker0(era, metadata_take_snap);
1639
1640 if (!strcasecmp(argv[0], "drop_metadata_snap"))
1641 return in_worker0(era, metadata_drop_snap);
1642
1643 DMERR("unsupported message '%s'", argv[0]);
1644 return -EINVAL;
1645}
1646
1647static sector_t get_dev_size(struct dm_dev *dev)
1648{
1649 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
1650}
1651
1652static int era_iterate_devices(struct dm_target *ti,
1653 iterate_devices_callout_fn fn, void *data)
1654{
1655 struct era *era = ti->private;
1656 return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
1657}
1658
1659static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
1660{
1661 struct era *era = ti->private;
1662 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
1663
1664 /*
1665 * If the system-determined stacked limits are compatible with the
1666 * era device's blocksize (io_opt is a factor) do not override them.
1667 */
1668 if (io_opt_sectors < era->sectors_per_block ||
1669 do_div(io_opt_sectors, era->sectors_per_block)) {
1670 blk_limits_io_min(limits, 0);
1671 blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT);
1672 }
1673}
1674
1675/*----------------------------------------------------------------*/
1676
1677static struct target_type era_target = {
1678 .name = "era",
1679 .version = {1, 0, 0},
1680 .module = THIS_MODULE,
1681 .ctr = era_ctr,
1682 .dtr = era_dtr,
1683 .map = era_map,
1684 .postsuspend = era_postsuspend,
1685 .preresume = era_preresume,
1686 .status = era_status,
1687 .message = era_message,
1688 .iterate_devices = era_iterate_devices,
1689 .io_hints = era_io_hints
1690};
1691
1692static int __init dm_era_init(void)
1693{
1694 int r;
1695
1696 r = dm_register_target(&era_target);
1697 if (r) {
1698 DMERR("era target registration failed: %d", r);
1699 return r;
1700 }
1701
1702 return 0;
1703}
1704
1705static void __exit dm_era_exit(void)
1706{
1707 dm_unregister_target(&era_target);
1708}
1709
1710module_init(dm_era_init);
1711module_exit(dm_era_exit);
1712
1713MODULE_DESCRIPTION(DM_NAME " era target");
1714MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
1715MODULE_LICENSE("GPL");