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1#include "dm.h"
2#include "persistent-data/dm-transaction-manager.h"
3#include "persistent-data/dm-bitset.h"
4#include "persistent-data/dm-space-map.h"
5
6#include <linux/dm-io.h>
7#include <linux/dm-kcopyd.h>
8#include <linux/init.h>
9#include <linux/mempool.h>
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/vmalloc.h>
13
14#define DM_MSG_PREFIX "era"
15
16#define SUPERBLOCK_LOCATION 0
17#define SUPERBLOCK_MAGIC 2126579579
18#define SUPERBLOCK_CSUM_XOR 146538381
19#define MIN_ERA_VERSION 1
20#define MAX_ERA_VERSION 1
21#define INVALID_WRITESET_ROOT SUPERBLOCK_LOCATION
22#define MIN_BLOCK_SIZE 8
23
24/*----------------------------------------------------------------
25 * Writeset
26 *--------------------------------------------------------------*/
27struct writeset_metadata {
28 uint32_t nr_bits;
29 dm_block_t root;
30};
31
32struct writeset {
33 struct writeset_metadata md;
34
35 /*
36 * An in core copy of the bits to save constantly doing look ups on
37 * disk.
38 */
39 unsigned long *bits;
40};
41
42/*
43 * This does not free off the on disk bitset as this will normally be done
44 * after digesting into the era array.
45 */
46static void writeset_free(struct writeset *ws)
47{
48 vfree(ws->bits);
49}
50
51static int setup_on_disk_bitset(struct dm_disk_bitset *info,
52 unsigned nr_bits, dm_block_t *root)
53{
54 int r;
55
56 r = dm_bitset_empty(info, root);
57 if (r)
58 return r;
59
60 return dm_bitset_resize(info, *root, 0, nr_bits, false, root);
61}
62
63static size_t bitset_size(unsigned nr_bits)
64{
65 return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG);
66}
67
68/*
69 * Allocates memory for the in core bitset.
70 */
71static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks)
72{
73 ws->md.nr_bits = nr_blocks;
74 ws->md.root = INVALID_WRITESET_ROOT;
75 ws->bits = vzalloc(bitset_size(nr_blocks));
76 if (!ws->bits) {
77 DMERR("%s: couldn't allocate in memory bitset", __func__);
78 return -ENOMEM;
79 }
80
81 return 0;
82}
83
84/*
85 * Wipes the in-core bitset, and creates a new on disk bitset.
86 */
87static int writeset_init(struct dm_disk_bitset *info, struct writeset *ws)
88{
89 int r;
90
91 memset(ws->bits, 0, bitset_size(ws->md.nr_bits));
92
93 r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root);
94 if (r) {
95 DMERR("%s: setup_on_disk_bitset failed", __func__);
96 return r;
97 }
98
99 return 0;
100}
101
102static bool writeset_marked(struct writeset *ws, dm_block_t block)
103{
104 return test_bit(block, ws->bits);
105}
106
107static int writeset_marked_on_disk(struct dm_disk_bitset *info,
108 struct writeset_metadata *m, dm_block_t block,
109 bool *result)
110{
111 dm_block_t old = m->root;
112
113 /*
114 * The bitset was flushed when it was archived, so we know there'll
115 * be no change to the root.
116 */
117 int r = dm_bitset_test_bit(info, m->root, block, &m->root, result);
118 if (r) {
119 DMERR("%s: dm_bitset_test_bit failed", __func__);
120 return r;
121 }
122
123 BUG_ON(m->root != old);
124
125 return r;
126}
127
128/*
129 * Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was.
130 */
131static int writeset_test_and_set(struct dm_disk_bitset *info,
132 struct writeset *ws, uint32_t block)
133{
134 int r;
135
136 if (!test_and_set_bit(block, ws->bits)) {
137 r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root);
138 if (r) {
139 /* FIXME: fail mode */
140 return r;
141 }
142
143 return 0;
144 }
145
146 return 1;
147}
148
149/*----------------------------------------------------------------
150 * On disk metadata layout
151 *--------------------------------------------------------------*/
152#define SPACE_MAP_ROOT_SIZE 128
153#define UUID_LEN 16
154
155struct writeset_disk {
156 __le32 nr_bits;
157 __le64 root;
158} __packed;
159
160struct superblock_disk {
161 __le32 csum;
162 __le32 flags;
163 __le64 blocknr;
164
165 __u8 uuid[UUID_LEN];
166 __le64 magic;
167 __le32 version;
168
169 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
170
171 __le32 data_block_size;
172 __le32 metadata_block_size;
173 __le32 nr_blocks;
174
175 __le32 current_era;
176 struct writeset_disk current_writeset;
177
178 /*
179 * Only these two fields are valid within the metadata snapshot.
180 */
181 __le64 writeset_tree_root;
182 __le64 era_array_root;
183
184 __le64 metadata_snap;
185} __packed;
186
187/*----------------------------------------------------------------
188 * Superblock validation
189 *--------------------------------------------------------------*/
190static void sb_prepare_for_write(struct dm_block_validator *v,
191 struct dm_block *b,
192 size_t sb_block_size)
193{
194 struct superblock_disk *disk = dm_block_data(b);
195
196 disk->blocknr = cpu_to_le64(dm_block_location(b));
197 disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags,
198 sb_block_size - sizeof(__le32),
199 SUPERBLOCK_CSUM_XOR));
200}
201
202static int check_metadata_version(struct superblock_disk *disk)
203{
204 uint32_t metadata_version = le32_to_cpu(disk->version);
205 if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) {
206 DMERR("Era metadata version %u found, but only versions between %u and %u supported.",
207 metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION);
208 return -EINVAL;
209 }
210
211 return 0;
212}
213
214static int sb_check(struct dm_block_validator *v,
215 struct dm_block *b,
216 size_t sb_block_size)
217{
218 struct superblock_disk *disk = dm_block_data(b);
219 __le32 csum_le;
220
221 if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) {
222 DMERR("sb_check failed: blocknr %llu: wanted %llu",
223 le64_to_cpu(disk->blocknr),
224 (unsigned long long)dm_block_location(b));
225 return -ENOTBLK;
226 }
227
228 if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) {
229 DMERR("sb_check failed: magic %llu: wanted %llu",
230 le64_to_cpu(disk->magic),
231 (unsigned long long) SUPERBLOCK_MAGIC);
232 return -EILSEQ;
233 }
234
235 csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags,
236 sb_block_size - sizeof(__le32),
237 SUPERBLOCK_CSUM_XOR));
238 if (csum_le != disk->csum) {
239 DMERR("sb_check failed: csum %u: wanted %u",
240 le32_to_cpu(csum_le), le32_to_cpu(disk->csum));
241 return -EILSEQ;
242 }
243
244 return check_metadata_version(disk);
245}
246
247static struct dm_block_validator sb_validator = {
248 .name = "superblock",
249 .prepare_for_write = sb_prepare_for_write,
250 .check = sb_check
251};
252
253/*----------------------------------------------------------------
254 * Low level metadata handling
255 *--------------------------------------------------------------*/
256#define DM_ERA_METADATA_BLOCK_SIZE 4096
257#define DM_ERA_METADATA_CACHE_SIZE 64
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 return dm_bm_unlock(b);
347}
348
349/*----------------------------------------------------------------*/
350
351static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk)
352{
353 disk->nr_bits = cpu_to_le32(core->nr_bits);
354 disk->root = cpu_to_le64(core->root);
355}
356
357static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core)
358{
359 core->nr_bits = le32_to_cpu(disk->nr_bits);
360 core->root = le64_to_cpu(disk->root);
361}
362
363static void ws_inc(void *context, const void *value)
364{
365 struct era_metadata *md = context;
366 struct writeset_disk ws_d;
367 dm_block_t b;
368
369 memcpy(&ws_d, value, sizeof(ws_d));
370 b = le64_to_cpu(ws_d.root);
371
372 dm_tm_inc(md->tm, b);
373}
374
375static void ws_dec(void *context, const void *value)
376{
377 struct era_metadata *md = context;
378 struct writeset_disk ws_d;
379 dm_block_t b;
380
381 memcpy(&ws_d, value, sizeof(ws_d));
382 b = le64_to_cpu(ws_d.root);
383
384 dm_bitset_del(&md->bitset_info, b);
385}
386
387static int ws_eq(void *context, const void *value1, const void *value2)
388{
389 return !memcmp(value1, value2, sizeof(struct writeset_metadata));
390}
391
392/*----------------------------------------------------------------*/
393
394static void setup_writeset_tree_info(struct era_metadata *md)
395{
396 struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type;
397 md->writeset_tree_info.tm = md->tm;
398 md->writeset_tree_info.levels = 1;
399 vt->context = md;
400 vt->size = sizeof(struct writeset_disk);
401 vt->inc = ws_inc;
402 vt->dec = ws_dec;
403 vt->equal = ws_eq;
404}
405
406static void setup_era_array_info(struct era_metadata *md)
407
408{
409 struct dm_btree_value_type vt;
410 vt.context = NULL;
411 vt.size = sizeof(__le32);
412 vt.inc = NULL;
413 vt.dec = NULL;
414 vt.equal = NULL;
415
416 dm_array_info_init(&md->era_array_info, md->tm, &vt);
417}
418
419static void setup_infos(struct era_metadata *md)
420{
421 dm_disk_bitset_init(md->tm, &md->bitset_info);
422 setup_writeset_tree_info(md);
423 setup_era_array_info(md);
424}
425
426/*----------------------------------------------------------------*/
427
428static int create_fresh_metadata(struct era_metadata *md)
429{
430 int r;
431
432 r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION,
433 &md->tm, &md->sm);
434 if (r < 0) {
435 DMERR("dm_tm_create_with_sm failed");
436 return r;
437 }
438
439 setup_infos(md);
440
441 r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root);
442 if (r) {
443 DMERR("couldn't create new writeset tree");
444 goto bad;
445 }
446
447 r = dm_array_empty(&md->era_array_info, &md->era_array_root);
448 if (r) {
449 DMERR("couldn't create era array");
450 goto bad;
451 }
452
453 return 0;
454
455bad:
456 dm_sm_destroy(md->sm);
457 dm_tm_destroy(md->tm);
458
459 return r;
460}
461
462static int save_sm_root(struct era_metadata *md)
463{
464 int r;
465 size_t metadata_len;
466
467 r = dm_sm_root_size(md->sm, &metadata_len);
468 if (r < 0)
469 return r;
470
471 return dm_sm_copy_root(md->sm, &md->metadata_space_map_root,
472 metadata_len);
473}
474
475static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk)
476{
477 memcpy(&disk->metadata_space_map_root,
478 &md->metadata_space_map_root,
479 sizeof(md->metadata_space_map_root));
480}
481
482/*
483 * Writes a superblock, including the static fields that don't get updated
484 * with every commit (possible optimisation here). 'md' should be fully
485 * constructed when this is called.
486 */
487static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk)
488{
489 disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
490 disk->flags = cpu_to_le32(0ul);
491
492 /* FIXME: can't keep blanking the uuid (uuid is currently unused though) */
493 memset(disk->uuid, 0, sizeof(disk->uuid));
494 disk->version = cpu_to_le32(MAX_ERA_VERSION);
495
496 copy_sm_root(md, disk);
497
498 disk->data_block_size = cpu_to_le32(md->block_size);
499 disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
500 disk->nr_blocks = cpu_to_le32(md->nr_blocks);
501 disk->current_era = cpu_to_le32(md->current_era);
502
503 ws_pack(&md->current_writeset->md, &disk->current_writeset);
504 disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root);
505 disk->era_array_root = cpu_to_le64(md->era_array_root);
506 disk->metadata_snap = cpu_to_le64(md->metadata_snap);
507}
508
509static int write_superblock(struct era_metadata *md)
510{
511 int r;
512 struct dm_block *sblock;
513 struct superblock_disk *disk;
514
515 r = save_sm_root(md);
516 if (r) {
517 DMERR("%s: save_sm_root failed", __func__);
518 return r;
519 }
520
521 r = superblock_lock_zero(md, &sblock);
522 if (r)
523 return r;
524
525 disk = dm_block_data(sblock);
526 prepare_superblock(md, disk);
527
528 return dm_tm_commit(md->tm, sblock);
529}
530
531/*
532 * Assumes block_size and the infos are set.
533 */
534static int format_metadata(struct era_metadata *md)
535{
536 int r;
537
538 r = create_fresh_metadata(md);
539 if (r)
540 return r;
541
542 r = write_superblock(md);
543 if (r) {
544 dm_sm_destroy(md->sm);
545 dm_tm_destroy(md->tm);
546 return r;
547 }
548
549 return 0;
550}
551
552static int open_metadata(struct era_metadata *md)
553{
554 int r;
555 struct dm_block *sblock;
556 struct superblock_disk *disk;
557
558 r = superblock_read_lock(md, &sblock);
559 if (r) {
560 DMERR("couldn't read_lock superblock");
561 return r;
562 }
563
564 disk = dm_block_data(sblock);
565 r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION,
566 disk->metadata_space_map_root,
567 sizeof(disk->metadata_space_map_root),
568 &md->tm, &md->sm);
569 if (r) {
570 DMERR("dm_tm_open_with_sm failed");
571 goto bad;
572 }
573
574 setup_infos(md);
575
576 md->block_size = le32_to_cpu(disk->data_block_size);
577 md->nr_blocks = le32_to_cpu(disk->nr_blocks);
578 md->current_era = le32_to_cpu(disk->current_era);
579
580 md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root);
581 md->era_array_root = le64_to_cpu(disk->era_array_root);
582 md->metadata_snap = le64_to_cpu(disk->metadata_snap);
583 md->archived_writesets = true;
584
585 return dm_bm_unlock(sblock);
586
587bad:
588 dm_bm_unlock(sblock);
589 return r;
590}
591
592static int open_or_format_metadata(struct era_metadata *md,
593 bool may_format)
594{
595 int r;
596 bool unformatted = false;
597
598 r = superblock_all_zeroes(md->bm, &unformatted);
599 if (r)
600 return r;
601
602 if (unformatted)
603 return may_format ? format_metadata(md) : -EPERM;
604
605 return open_metadata(md);
606}
607
608static int create_persistent_data_objects(struct era_metadata *md,
609 bool may_format)
610{
611 int r;
612
613 md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE,
614 DM_ERA_METADATA_CACHE_SIZE,
615 ERA_MAX_CONCURRENT_LOCKS);
616 if (IS_ERR(md->bm)) {
617 DMERR("could not create block manager");
618 return PTR_ERR(md->bm);
619 }
620
621 r = open_or_format_metadata(md, may_format);
622 if (r)
623 dm_block_manager_destroy(md->bm);
624
625 return r;
626}
627
628static void destroy_persistent_data_objects(struct era_metadata *md)
629{
630 dm_sm_destroy(md->sm);
631 dm_tm_destroy(md->tm);
632 dm_block_manager_destroy(md->bm);
633}
634
635/*
636 * This waits until all era_map threads have picked up the new filter.
637 */
638static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset)
639{
640 rcu_assign_pointer(md->current_writeset, new_writeset);
641 synchronize_rcu();
642}
643
644/*----------------------------------------------------------------
645 * Writesets get 'digested' into the main era array.
646 *
647 * We're using a coroutine here so the worker thread can do the digestion,
648 * thus avoiding synchronisation of the metadata. Digesting a whole
649 * writeset in one go would cause too much latency.
650 *--------------------------------------------------------------*/
651struct digest {
652 uint32_t era;
653 unsigned nr_bits, current_bit;
654 struct writeset_metadata writeset;
655 __le32 value;
656 struct dm_disk_bitset info;
657
658 int (*step)(struct era_metadata *, struct digest *);
659};
660
661static int metadata_digest_lookup_writeset(struct era_metadata *md,
662 struct digest *d);
663
664static int metadata_digest_remove_writeset(struct era_metadata *md,
665 struct digest *d)
666{
667 int r;
668 uint64_t key = d->era;
669
670 r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root,
671 &key, &md->writeset_tree_root);
672 if (r) {
673 DMERR("%s: dm_btree_remove failed", __func__);
674 return r;
675 }
676
677 d->step = metadata_digest_lookup_writeset;
678 return 0;
679}
680
681#define INSERTS_PER_STEP 100
682
683static int metadata_digest_transcribe_writeset(struct era_metadata *md,
684 struct digest *d)
685{
686 int r;
687 bool marked;
688 unsigned b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits);
689
690 for (b = d->current_bit; b < e; b++) {
691 r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked);
692 if (r) {
693 DMERR("%s: writeset_marked_on_disk failed", __func__);
694 return r;
695 }
696
697 if (!marked)
698 continue;
699
700 __dm_bless_for_disk(&d->value);
701 r = dm_array_set_value(&md->era_array_info, md->era_array_root,
702 b, &d->value, &md->era_array_root);
703 if (r) {
704 DMERR("%s: dm_array_set_value failed", __func__);
705 return r;
706 }
707 }
708
709 if (b == d->nr_bits)
710 d->step = metadata_digest_remove_writeset;
711 else
712 d->current_bit = b;
713
714 return 0;
715}
716
717static int metadata_digest_lookup_writeset(struct era_metadata *md,
718 struct digest *d)
719{
720 int r;
721 uint64_t key;
722 struct writeset_disk disk;
723
724 r = dm_btree_find_lowest_key(&md->writeset_tree_info,
725 md->writeset_tree_root, &key);
726 if (r < 0)
727 return r;
728
729 d->era = key;
730
731 r = dm_btree_lookup(&md->writeset_tree_info,
732 md->writeset_tree_root, &key, &disk);
733 if (r) {
734 if (r == -ENODATA) {
735 d->step = NULL;
736 return 0;
737 }
738
739 DMERR("%s: dm_btree_lookup failed", __func__);
740 return r;
741 }
742
743 ws_unpack(&disk, &d->writeset);
744 d->value = cpu_to_le32(key);
745
746 d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks);
747 d->current_bit = 0;
748 d->step = metadata_digest_transcribe_writeset;
749
750 return 0;
751}
752
753static int metadata_digest_start(struct era_metadata *md, struct digest *d)
754{
755 if (d->step)
756 return 0;
757
758 memset(d, 0, sizeof(*d));
759
760 /*
761 * We initialise another bitset info to avoid any caching side
762 * effects with the previous one.
763 */
764 dm_disk_bitset_init(md->tm, &d->info);
765 d->step = metadata_digest_lookup_writeset;
766
767 return 0;
768}
769
770/*----------------------------------------------------------------
771 * High level metadata interface. Target methods should use these, and not
772 * the lower level ones.
773 *--------------------------------------------------------------*/
774static struct era_metadata *metadata_open(struct block_device *bdev,
775 sector_t block_size,
776 bool may_format)
777{
778 int r;
779 struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL);
780
781 if (!md)
782 return NULL;
783
784 md->bdev = bdev;
785 md->block_size = block_size;
786
787 md->writesets[0].md.root = INVALID_WRITESET_ROOT;
788 md->writesets[1].md.root = INVALID_WRITESET_ROOT;
789 md->current_writeset = &md->writesets[0];
790
791 r = create_persistent_data_objects(md, may_format);
792 if (r) {
793 kfree(md);
794 return ERR_PTR(r);
795 }
796
797 return md;
798}
799
800static void metadata_close(struct era_metadata *md)
801{
802 destroy_persistent_data_objects(md);
803 kfree(md);
804}
805
806static bool valid_nr_blocks(dm_block_t n)
807{
808 /*
809 * dm_bitset restricts us to 2^32. test_bit & co. restrict us
810 * further to 2^31 - 1
811 */
812 return n < (1ull << 31);
813}
814
815static int metadata_resize(struct era_metadata *md, void *arg)
816{
817 int r;
818 dm_block_t *new_size = arg;
819 __le32 value;
820
821 if (!valid_nr_blocks(*new_size)) {
822 DMERR("Invalid number of origin blocks %llu",
823 (unsigned long long) *new_size);
824 return -EINVAL;
825 }
826
827 writeset_free(&md->writesets[0]);
828 writeset_free(&md->writesets[1]);
829
830 r = writeset_alloc(&md->writesets[0], *new_size);
831 if (r) {
832 DMERR("%s: writeset_alloc failed for writeset 0", __func__);
833 return r;
834 }
835
836 r = writeset_alloc(&md->writesets[1], *new_size);
837 if (r) {
838 DMERR("%s: writeset_alloc failed for writeset 1", __func__);
839 return r;
840 }
841
842 value = cpu_to_le32(0u);
843 __dm_bless_for_disk(&value);
844 r = dm_array_resize(&md->era_array_info, md->era_array_root,
845 md->nr_blocks, *new_size,
846 &value, &md->era_array_root);
847 if (r) {
848 DMERR("%s: dm_array_resize failed", __func__);
849 return r;
850 }
851
852 md->nr_blocks = *new_size;
853 return 0;
854}
855
856static int metadata_era_archive(struct era_metadata *md)
857{
858 int r;
859 uint64_t keys[1];
860 struct writeset_disk value;
861
862 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
863 &md->current_writeset->md.root);
864 if (r) {
865 DMERR("%s: dm_bitset_flush failed", __func__);
866 return r;
867 }
868
869 ws_pack(&md->current_writeset->md, &value);
870 md->current_writeset->md.root = INVALID_WRITESET_ROOT;
871
872 keys[0] = md->current_era;
873 __dm_bless_for_disk(&value);
874 r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root,
875 keys, &value, &md->writeset_tree_root);
876 if (r) {
877 DMERR("%s: couldn't insert writeset into btree", __func__);
878 /* FIXME: fail mode */
879 return r;
880 }
881
882 md->archived_writesets = true;
883
884 return 0;
885}
886
887static struct writeset *next_writeset(struct era_metadata *md)
888{
889 return (md->current_writeset == &md->writesets[0]) ?
890 &md->writesets[1] : &md->writesets[0];
891}
892
893static int metadata_new_era(struct era_metadata *md)
894{
895 int r;
896 struct writeset *new_writeset = next_writeset(md);
897
898 r = writeset_init(&md->bitset_info, new_writeset);
899 if (r) {
900 DMERR("%s: writeset_init failed", __func__);
901 return r;
902 }
903
904 swap_writeset(md, new_writeset);
905 md->current_era++;
906
907 return 0;
908}
909
910static int metadata_era_rollover(struct era_metadata *md)
911{
912 int r;
913
914 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
915 r = metadata_era_archive(md);
916 if (r) {
917 DMERR("%s: metadata_archive_era failed", __func__);
918 /* FIXME: fail mode? */
919 return r;
920 }
921 }
922
923 r = metadata_new_era(md);
924 if (r) {
925 DMERR("%s: new era failed", __func__);
926 /* FIXME: fail mode */
927 return r;
928 }
929
930 return 0;
931}
932
933static bool metadata_current_marked(struct era_metadata *md, dm_block_t block)
934{
935 bool r;
936 struct writeset *ws;
937
938 rcu_read_lock();
939 ws = rcu_dereference(md->current_writeset);
940 r = writeset_marked(ws, block);
941 rcu_read_unlock();
942
943 return r;
944}
945
946static int metadata_commit(struct era_metadata *md)
947{
948 int r;
949 struct dm_block *sblock;
950
951 if (md->current_writeset->md.root != SUPERBLOCK_LOCATION) {
952 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
953 &md->current_writeset->md.root);
954 if (r) {
955 DMERR("%s: bitset flush failed", __func__);
956 return r;
957 }
958 }
959
960 r = save_sm_root(md);
961 if (r) {
962 DMERR("%s: save_sm_root failed", __func__);
963 return r;
964 }
965
966 r = dm_tm_pre_commit(md->tm);
967 if (r) {
968 DMERR("%s: pre commit failed", __func__);
969 return r;
970 }
971
972 r = superblock_lock(md, &sblock);
973 if (r) {
974 DMERR("%s: superblock lock failed", __func__);
975 return r;
976 }
977
978 prepare_superblock(md, dm_block_data(sblock));
979
980 return dm_tm_commit(md->tm, sblock);
981}
982
983static int metadata_checkpoint(struct era_metadata *md)
984{
985 /*
986 * For now we just rollover, but later I want to put a check in to
987 * avoid this if the filter is still pretty fresh.
988 */
989 return metadata_era_rollover(md);
990}
991
992/*
993 * Metadata snapshots allow userland to access era data.
994 */
995static int metadata_take_snap(struct era_metadata *md)
996{
997 int r, inc;
998 struct dm_block *clone;
999
1000 if (md->metadata_snap != SUPERBLOCK_LOCATION) {
1001 DMERR("%s: metadata snapshot already exists", __func__);
1002 return -EINVAL;
1003 }
1004
1005 r = metadata_era_rollover(md);
1006 if (r) {
1007 DMERR("%s: era rollover failed", __func__);
1008 return r;
1009 }
1010
1011 r = metadata_commit(md);
1012 if (r) {
1013 DMERR("%s: pre commit failed", __func__);
1014 return r;
1015 }
1016
1017 r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION);
1018 if (r) {
1019 DMERR("%s: couldn't increment superblock", __func__);
1020 return r;
1021 }
1022
1023 r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION,
1024 &sb_validator, &clone, &inc);
1025 if (r) {
1026 DMERR("%s: couldn't shadow superblock", __func__);
1027 dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION);
1028 return r;
1029 }
1030 BUG_ON(!inc);
1031
1032 r = dm_sm_inc_block(md->sm, md->writeset_tree_root);
1033 if (r) {
1034 DMERR("%s: couldn't inc writeset tree root", __func__);
1035 dm_tm_unlock(md->tm, clone);
1036 return r;
1037 }
1038
1039 r = dm_sm_inc_block(md->sm, md->era_array_root);
1040 if (r) {
1041 DMERR("%s: couldn't inc era tree root", __func__);
1042 dm_sm_dec_block(md->sm, md->writeset_tree_root);
1043 dm_tm_unlock(md->tm, clone);
1044 return r;
1045 }
1046
1047 md->metadata_snap = dm_block_location(clone);
1048
1049 r = dm_tm_unlock(md->tm, clone);
1050 if (r) {
1051 DMERR("%s: couldn't unlock clone", __func__);
1052 md->metadata_snap = SUPERBLOCK_LOCATION;
1053 return r;
1054 }
1055
1056 return 0;
1057}
1058
1059static int metadata_drop_snap(struct era_metadata *md)
1060{
1061 int r;
1062 dm_block_t location;
1063 struct dm_block *clone;
1064 struct superblock_disk *disk;
1065
1066 if (md->metadata_snap == SUPERBLOCK_LOCATION) {
1067 DMERR("%s: no snap to drop", __func__);
1068 return -EINVAL;
1069 }
1070
1071 r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone);
1072 if (r) {
1073 DMERR("%s: couldn't read lock superblock clone", __func__);
1074 return r;
1075 }
1076
1077 /*
1078 * Whatever happens now we'll commit with no record of the metadata
1079 * snap.
1080 */
1081 md->metadata_snap = SUPERBLOCK_LOCATION;
1082
1083 disk = dm_block_data(clone);
1084 r = dm_btree_del(&md->writeset_tree_info,
1085 le64_to_cpu(disk->writeset_tree_root));
1086 if (r) {
1087 DMERR("%s: error deleting writeset tree clone", __func__);
1088 dm_tm_unlock(md->tm, clone);
1089 return r;
1090 }
1091
1092 r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root));
1093 if (r) {
1094 DMERR("%s: error deleting era array clone", __func__);
1095 dm_tm_unlock(md->tm, clone);
1096 return r;
1097 }
1098
1099 location = dm_block_location(clone);
1100 dm_tm_unlock(md->tm, clone);
1101
1102 return dm_sm_dec_block(md->sm, location);
1103}
1104
1105struct metadata_stats {
1106 dm_block_t used;
1107 dm_block_t total;
1108 dm_block_t snap;
1109 uint32_t era;
1110};
1111
1112static int metadata_get_stats(struct era_metadata *md, void *ptr)
1113{
1114 int r;
1115 struct metadata_stats *s = ptr;
1116 dm_block_t nr_free, nr_total;
1117
1118 r = dm_sm_get_nr_free(md->sm, &nr_free);
1119 if (r) {
1120 DMERR("dm_sm_get_nr_free returned %d", r);
1121 return r;
1122 }
1123
1124 r = dm_sm_get_nr_blocks(md->sm, &nr_total);
1125 if (r) {
1126 DMERR("dm_pool_get_metadata_dev_size returned %d", r);
1127 return r;
1128 }
1129
1130 s->used = nr_total - nr_free;
1131 s->total = nr_total;
1132 s->snap = md->metadata_snap;
1133 s->era = md->current_era;
1134
1135 return 0;
1136}
1137
1138/*----------------------------------------------------------------*/
1139
1140struct era {
1141 struct dm_target *ti;
1142 struct dm_target_callbacks callbacks;
1143
1144 struct dm_dev *metadata_dev;
1145 struct dm_dev *origin_dev;
1146
1147 dm_block_t nr_blocks;
1148 uint32_t sectors_per_block;
1149 int sectors_per_block_shift;
1150 struct era_metadata *md;
1151
1152 struct workqueue_struct *wq;
1153 struct work_struct worker;
1154
1155 spinlock_t deferred_lock;
1156 struct bio_list deferred_bios;
1157
1158 spinlock_t rpc_lock;
1159 struct list_head rpc_calls;
1160
1161 struct digest digest;
1162 atomic_t suspended;
1163};
1164
1165struct rpc {
1166 struct list_head list;
1167
1168 int (*fn0)(struct era_metadata *);
1169 int (*fn1)(struct era_metadata *, void *);
1170 void *arg;
1171 int result;
1172
1173 struct completion complete;
1174};
1175
1176/*----------------------------------------------------------------
1177 * Remapping.
1178 *---------------------------------------------------------------*/
1179static bool block_size_is_power_of_two(struct era *era)
1180{
1181 return era->sectors_per_block_shift >= 0;
1182}
1183
1184static dm_block_t get_block(struct era *era, struct bio *bio)
1185{
1186 sector_t block_nr = bio->bi_iter.bi_sector;
1187
1188 if (!block_size_is_power_of_two(era))
1189 (void) sector_div(block_nr, era->sectors_per_block);
1190 else
1191 block_nr >>= era->sectors_per_block_shift;
1192
1193 return block_nr;
1194}
1195
1196static void remap_to_origin(struct era *era, struct bio *bio)
1197{
1198 bio->bi_bdev = era->origin_dev->bdev;
1199}
1200
1201/*----------------------------------------------------------------
1202 * Worker thread
1203 *--------------------------------------------------------------*/
1204static void wake_worker(struct era *era)
1205{
1206 if (!atomic_read(&era->suspended))
1207 queue_work(era->wq, &era->worker);
1208}
1209
1210static void process_old_eras(struct era *era)
1211{
1212 int r;
1213
1214 if (!era->digest.step)
1215 return;
1216
1217 r = era->digest.step(era->md, &era->digest);
1218 if (r < 0) {
1219 DMERR("%s: digest step failed, stopping digestion", __func__);
1220 era->digest.step = NULL;
1221
1222 } else if (era->digest.step)
1223 wake_worker(era);
1224}
1225
1226static void process_deferred_bios(struct era *era)
1227{
1228 int r;
1229 struct bio_list deferred_bios, marked_bios;
1230 struct bio *bio;
1231 bool commit_needed = false;
1232 bool failed = false;
1233
1234 bio_list_init(&deferred_bios);
1235 bio_list_init(&marked_bios);
1236
1237 spin_lock(&era->deferred_lock);
1238 bio_list_merge(&deferred_bios, &era->deferred_bios);
1239 bio_list_init(&era->deferred_bios);
1240 spin_unlock(&era->deferred_lock);
1241
1242 while ((bio = bio_list_pop(&deferred_bios))) {
1243 r = writeset_test_and_set(&era->md->bitset_info,
1244 era->md->current_writeset,
1245 get_block(era, bio));
1246 if (r < 0) {
1247 /*
1248 * This is bad news, we need to rollback.
1249 * FIXME: finish.
1250 */
1251 failed = true;
1252
1253 } else if (r == 0)
1254 commit_needed = true;
1255
1256 bio_list_add(&marked_bios, bio);
1257 }
1258
1259 if (commit_needed) {
1260 r = metadata_commit(era->md);
1261 if (r)
1262 failed = true;
1263 }
1264
1265 if (failed)
1266 while ((bio = bio_list_pop(&marked_bios)))
1267 bio_io_error(bio);
1268 else
1269 while ((bio = bio_list_pop(&marked_bios)))
1270 generic_make_request(bio);
1271}
1272
1273static void process_rpc_calls(struct era *era)
1274{
1275 int r;
1276 bool need_commit = false;
1277 struct list_head calls;
1278 struct rpc *rpc, *tmp;
1279
1280 INIT_LIST_HEAD(&calls);
1281 spin_lock(&era->rpc_lock);
1282 list_splice_init(&era->rpc_calls, &calls);
1283 spin_unlock(&era->rpc_lock);
1284
1285 list_for_each_entry_safe(rpc, tmp, &calls, list) {
1286 rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg);
1287 need_commit = true;
1288 }
1289
1290 if (need_commit) {
1291 r = metadata_commit(era->md);
1292 if (r)
1293 list_for_each_entry_safe(rpc, tmp, &calls, list)
1294 rpc->result = r;
1295 }
1296
1297 list_for_each_entry_safe(rpc, tmp, &calls, list)
1298 complete(&rpc->complete);
1299}
1300
1301static void kick_off_digest(struct era *era)
1302{
1303 if (era->md->archived_writesets) {
1304 era->md->archived_writesets = false;
1305 metadata_digest_start(era->md, &era->digest);
1306 }
1307}
1308
1309static void do_work(struct work_struct *ws)
1310{
1311 struct era *era = container_of(ws, struct era, worker);
1312
1313 kick_off_digest(era);
1314 process_old_eras(era);
1315 process_deferred_bios(era);
1316 process_rpc_calls(era);
1317}
1318
1319static void defer_bio(struct era *era, struct bio *bio)
1320{
1321 spin_lock(&era->deferred_lock);
1322 bio_list_add(&era->deferred_bios, bio);
1323 spin_unlock(&era->deferred_lock);
1324
1325 wake_worker(era);
1326}
1327
1328/*
1329 * Make an rpc call to the worker to change the metadata.
1330 */
1331static int perform_rpc(struct era *era, struct rpc *rpc)
1332{
1333 rpc->result = 0;
1334 init_completion(&rpc->complete);
1335
1336 spin_lock(&era->rpc_lock);
1337 list_add(&rpc->list, &era->rpc_calls);
1338 spin_unlock(&era->rpc_lock);
1339
1340 wake_worker(era);
1341 wait_for_completion(&rpc->complete);
1342
1343 return rpc->result;
1344}
1345
1346static int in_worker0(struct era *era, int (*fn)(struct era_metadata *))
1347{
1348 struct rpc rpc;
1349 rpc.fn0 = fn;
1350 rpc.fn1 = NULL;
1351
1352 return perform_rpc(era, &rpc);
1353}
1354
1355static int in_worker1(struct era *era,
1356 int (*fn)(struct era_metadata *, void *), void *arg)
1357{
1358 struct rpc rpc;
1359 rpc.fn0 = NULL;
1360 rpc.fn1 = fn;
1361 rpc.arg = arg;
1362
1363 return perform_rpc(era, &rpc);
1364}
1365
1366static void start_worker(struct era *era)
1367{
1368 atomic_set(&era->suspended, 0);
1369}
1370
1371static void stop_worker(struct era *era)
1372{
1373 atomic_set(&era->suspended, 1);
1374 flush_workqueue(era->wq);
1375}
1376
1377/*----------------------------------------------------------------
1378 * Target methods
1379 *--------------------------------------------------------------*/
1380static int dev_is_congested(struct dm_dev *dev, int bdi_bits)
1381{
1382 struct request_queue *q = bdev_get_queue(dev->bdev);
1383 return bdi_congested(&q->backing_dev_info, bdi_bits);
1384}
1385
1386static int era_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1387{
1388 struct era *era = container_of(cb, struct era, callbacks);
1389 return dev_is_congested(era->origin_dev, bdi_bits);
1390}
1391
1392static void era_destroy(struct era *era)
1393{
1394 metadata_close(era->md);
1395
1396 if (era->wq)
1397 destroy_workqueue(era->wq);
1398
1399 if (era->origin_dev)
1400 dm_put_device(era->ti, era->origin_dev);
1401
1402 if (era->metadata_dev)
1403 dm_put_device(era->ti, era->metadata_dev);
1404
1405 kfree(era);
1406}
1407
1408static dm_block_t calc_nr_blocks(struct era *era)
1409{
1410 return dm_sector_div_up(era->ti->len, era->sectors_per_block);
1411}
1412
1413static bool valid_block_size(dm_block_t block_size)
1414{
1415 bool greater_than_zero = block_size > 0;
1416 bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0;
1417
1418 return greater_than_zero && multiple_of_min_block_size;
1419}
1420
1421/*
1422 * <metadata dev> <data dev> <data block size (sectors)>
1423 */
1424static int era_ctr(struct dm_target *ti, unsigned argc, char **argv)
1425{
1426 int r;
1427 char dummy;
1428 struct era *era;
1429 struct era_metadata *md;
1430
1431 if (argc != 3) {
1432 ti->error = "Invalid argument count";
1433 return -EINVAL;
1434 }
1435
1436 era = kzalloc(sizeof(*era), GFP_KERNEL);
1437 if (!era) {
1438 ti->error = "Error allocating era structure";
1439 return -ENOMEM;
1440 }
1441
1442 era->ti = ti;
1443
1444 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &era->metadata_dev);
1445 if (r) {
1446 ti->error = "Error opening metadata device";
1447 era_destroy(era);
1448 return -EINVAL;
1449 }
1450
1451 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &era->origin_dev);
1452 if (r) {
1453 ti->error = "Error opening data device";
1454 era_destroy(era);
1455 return -EINVAL;
1456 }
1457
1458 r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy);
1459 if (r != 1) {
1460 ti->error = "Error parsing block size";
1461 era_destroy(era);
1462 return -EINVAL;
1463 }
1464
1465 r = dm_set_target_max_io_len(ti, era->sectors_per_block);
1466 if (r) {
1467 ti->error = "could not set max io len";
1468 era_destroy(era);
1469 return -EINVAL;
1470 }
1471
1472 if (!valid_block_size(era->sectors_per_block)) {
1473 ti->error = "Invalid block size";
1474 era_destroy(era);
1475 return -EINVAL;
1476 }
1477 if (era->sectors_per_block & (era->sectors_per_block - 1))
1478 era->sectors_per_block_shift = -1;
1479 else
1480 era->sectors_per_block_shift = __ffs(era->sectors_per_block);
1481
1482 md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true);
1483 if (IS_ERR(md)) {
1484 ti->error = "Error reading metadata";
1485 era_destroy(era);
1486 return PTR_ERR(md);
1487 }
1488 era->md = md;
1489
1490 era->nr_blocks = calc_nr_blocks(era);
1491
1492 r = metadata_resize(era->md, &era->nr_blocks);
1493 if (r) {
1494 ti->error = "couldn't resize metadata";
1495 era_destroy(era);
1496 return -ENOMEM;
1497 }
1498
1499 era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1500 if (!era->wq) {
1501 ti->error = "could not create workqueue for metadata object";
1502 era_destroy(era);
1503 return -ENOMEM;
1504 }
1505 INIT_WORK(&era->worker, do_work);
1506
1507 spin_lock_init(&era->deferred_lock);
1508 bio_list_init(&era->deferred_bios);
1509
1510 spin_lock_init(&era->rpc_lock);
1511 INIT_LIST_HEAD(&era->rpc_calls);
1512
1513 ti->private = era;
1514 ti->num_flush_bios = 1;
1515 ti->flush_supported = true;
1516
1517 ti->num_discard_bios = 1;
1518 ti->discards_supported = true;
1519 era->callbacks.congested_fn = era_is_congested;
1520 dm_table_add_target_callbacks(ti->table, &era->callbacks);
1521
1522 return 0;
1523}
1524
1525static void era_dtr(struct dm_target *ti)
1526{
1527 era_destroy(ti->private);
1528}
1529
1530static int era_map(struct dm_target *ti, struct bio *bio)
1531{
1532 struct era *era = ti->private;
1533 dm_block_t block = get_block(era, bio);
1534
1535 /*
1536 * All bios get remapped to the origin device. We do this now, but
1537 * it may not get issued until later. Depending on whether the
1538 * block is marked in this era.
1539 */
1540 remap_to_origin(era, bio);
1541
1542 /*
1543 * REQ_FLUSH bios carry no data, so we're not interested in them.
1544 */
1545 if (!(bio->bi_rw & REQ_FLUSH) &&
1546 (bio_data_dir(bio) == WRITE) &&
1547 !metadata_current_marked(era->md, block)) {
1548 defer_bio(era, bio);
1549 return DM_MAPIO_SUBMITTED;
1550 }
1551
1552 return DM_MAPIO_REMAPPED;
1553}
1554
1555static void era_postsuspend(struct dm_target *ti)
1556{
1557 int r;
1558 struct era *era = ti->private;
1559
1560 r = in_worker0(era, metadata_era_archive);
1561 if (r) {
1562 DMERR("%s: couldn't archive current era", __func__);
1563 /* FIXME: fail mode */
1564 }
1565
1566 stop_worker(era);
1567}
1568
1569static int era_preresume(struct dm_target *ti)
1570{
1571 int r;
1572 struct era *era = ti->private;
1573 dm_block_t new_size = calc_nr_blocks(era);
1574
1575 if (era->nr_blocks != new_size) {
1576 r = in_worker1(era, metadata_resize, &new_size);
1577 if (r)
1578 return r;
1579
1580 era->nr_blocks = new_size;
1581 }
1582
1583 start_worker(era);
1584
1585 r = in_worker0(era, metadata_new_era);
1586 if (r) {
1587 DMERR("%s: metadata_era_rollover failed", __func__);
1588 return r;
1589 }
1590
1591 return 0;
1592}
1593
1594/*
1595 * Status format:
1596 *
1597 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
1598 * <current era> <held metadata root | '-'>
1599 */
1600static void era_status(struct dm_target *ti, status_type_t type,
1601 unsigned status_flags, char *result, unsigned maxlen)
1602{
1603 int r;
1604 struct era *era = ti->private;
1605 ssize_t sz = 0;
1606 struct metadata_stats stats;
1607 char buf[BDEVNAME_SIZE];
1608
1609 switch (type) {
1610 case STATUSTYPE_INFO:
1611 r = in_worker1(era, metadata_get_stats, &stats);
1612 if (r)
1613 goto err;
1614
1615 DMEMIT("%u %llu/%llu %u",
1616 (unsigned) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
1617 (unsigned long long) stats.used,
1618 (unsigned long long) stats.total,
1619 (unsigned) stats.era);
1620
1621 if (stats.snap != SUPERBLOCK_LOCATION)
1622 DMEMIT(" %llu", stats.snap);
1623 else
1624 DMEMIT(" -");
1625 break;
1626
1627 case STATUSTYPE_TABLE:
1628 format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
1629 DMEMIT("%s ", buf);
1630 format_dev_t(buf, era->origin_dev->bdev->bd_dev);
1631 DMEMIT("%s %u", buf, era->sectors_per_block);
1632 break;
1633 }
1634
1635 return;
1636
1637err:
1638 DMEMIT("Error");
1639}
1640
1641static int era_message(struct dm_target *ti, unsigned argc, char **argv)
1642{
1643 struct era *era = ti->private;
1644
1645 if (argc != 1) {
1646 DMERR("incorrect number of message arguments");
1647 return -EINVAL;
1648 }
1649
1650 if (!strcasecmp(argv[0], "checkpoint"))
1651 return in_worker0(era, metadata_checkpoint);
1652
1653 if (!strcasecmp(argv[0], "take_metadata_snap"))
1654 return in_worker0(era, metadata_take_snap);
1655
1656 if (!strcasecmp(argv[0], "drop_metadata_snap"))
1657 return in_worker0(era, metadata_drop_snap);
1658
1659 DMERR("unsupported message '%s'", argv[0]);
1660 return -EINVAL;
1661}
1662
1663static sector_t get_dev_size(struct dm_dev *dev)
1664{
1665 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
1666}
1667
1668static int era_iterate_devices(struct dm_target *ti,
1669 iterate_devices_callout_fn fn, void *data)
1670{
1671 struct era *era = ti->private;
1672 return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
1673}
1674
1675static int era_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1676 struct bio_vec *biovec, int max_size)
1677{
1678 struct era *era = ti->private;
1679 struct request_queue *q = bdev_get_queue(era->origin_dev->bdev);
1680
1681 if (!q->merge_bvec_fn)
1682 return max_size;
1683
1684 bvm->bi_bdev = era->origin_dev->bdev;
1685
1686 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1687}
1688
1689static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
1690{
1691 struct era *era = ti->private;
1692 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
1693
1694 /*
1695 * If the system-determined stacked limits are compatible with the
1696 * era device's blocksize (io_opt is a factor) do not override them.
1697 */
1698 if (io_opt_sectors < era->sectors_per_block ||
1699 do_div(io_opt_sectors, era->sectors_per_block)) {
1700 blk_limits_io_min(limits, 0);
1701 blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT);
1702 }
1703}
1704
1705/*----------------------------------------------------------------*/
1706
1707static struct target_type era_target = {
1708 .name = "era",
1709 .version = {1, 0, 0},
1710 .module = THIS_MODULE,
1711 .ctr = era_ctr,
1712 .dtr = era_dtr,
1713 .map = era_map,
1714 .postsuspend = era_postsuspend,
1715 .preresume = era_preresume,
1716 .status = era_status,
1717 .message = era_message,
1718 .iterate_devices = era_iterate_devices,
1719 .merge = era_merge,
1720 .io_hints = era_io_hints
1721};
1722
1723static int __init dm_era_init(void)
1724{
1725 int r;
1726
1727 r = dm_register_target(&era_target);
1728 if (r) {
1729 DMERR("era target registration failed: %d", r);
1730 return r;
1731 }
1732
1733 return 0;
1734}
1735
1736static void __exit dm_era_exit(void)
1737{
1738 dm_unregister_target(&era_target);
1739}
1740
1741module_init(dm_era_init);
1742module_exit(dm_era_exit);
1743
1744MODULE_DESCRIPTION(DM_NAME " era target");
1745MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
1746MODULE_LICENSE("GPL");