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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 ws->bits = NULL;
51}
52
53static int setup_on_disk_bitset(struct dm_disk_bitset *info,
54 unsigned nr_bits, dm_block_t *root)
55{
56 int r;
57
58 r = dm_bitset_empty(info, root);
59 if (r)
60 return r;
61
62 return dm_bitset_resize(info, *root, 0, nr_bits, false, root);
63}
64
65static size_t bitset_size(unsigned nr_bits)
66{
67 return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG);
68}
69
70/*
71 * Allocates memory for the in core bitset.
72 */
73static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks)
74{
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 dm_block_t nr_blocks)
89{
90 int r;
91
92 memset(ws->bits, 0, bitset_size(nr_blocks));
93
94 ws->md.nr_bits = nr_blocks;
95 r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root);
96 if (r) {
97 DMERR("%s: setup_on_disk_bitset failed", __func__);
98 return r;
99 }
100
101 return 0;
102}
103
104static bool writeset_marked(struct writeset *ws, dm_block_t block)
105{
106 return test_bit(block, ws->bits);
107}
108
109static int writeset_marked_on_disk(struct dm_disk_bitset *info,
110 struct writeset_metadata *m, dm_block_t block,
111 bool *result)
112{
113 dm_block_t old = m->root;
114
115 /*
116 * The bitset was flushed when it was archived, so we know there'll
117 * be no change to the root.
118 */
119 int r = dm_bitset_test_bit(info, m->root, block, &m->root, result);
120 if (r) {
121 DMERR("%s: dm_bitset_test_bit failed", __func__);
122 return r;
123 }
124
125 BUG_ON(m->root != old);
126
127 return r;
128}
129
130/*
131 * Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was.
132 */
133static int writeset_test_and_set(struct dm_disk_bitset *info,
134 struct writeset *ws, uint32_t block)
135{
136 int r;
137
138 if (!test_bit(block, ws->bits)) {
139 r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root);
140 if (r) {
141 /* FIXME: fail mode */
142 return r;
143 }
144
145 return 0;
146 }
147
148 return 1;
149}
150
151/*----------------------------------------------------------------
152 * On disk metadata layout
153 *--------------------------------------------------------------*/
154#define SPACE_MAP_ROOT_SIZE 128
155#define UUID_LEN 16
156
157struct writeset_disk {
158 __le32 nr_bits;
159 __le64 root;
160} __packed;
161
162struct superblock_disk {
163 __le32 csum;
164 __le32 flags;
165 __le64 blocknr;
166
167 __u8 uuid[UUID_LEN];
168 __le64 magic;
169 __le32 version;
170
171 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
172
173 __le32 data_block_size;
174 __le32 metadata_block_size;
175 __le32 nr_blocks;
176
177 __le32 current_era;
178 struct writeset_disk current_writeset;
179
180 /*
181 * Only these two fields are valid within the metadata snapshot.
182 */
183 __le64 writeset_tree_root;
184 __le64 era_array_root;
185
186 __le64 metadata_snap;
187} __packed;
188
189/*----------------------------------------------------------------
190 * Superblock validation
191 *--------------------------------------------------------------*/
192static void sb_prepare_for_write(struct dm_block_validator *v,
193 struct dm_block *b,
194 size_t sb_block_size)
195{
196 struct superblock_disk *disk = dm_block_data(b);
197
198 disk->blocknr = cpu_to_le64(dm_block_location(b));
199 disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags,
200 sb_block_size - sizeof(__le32),
201 SUPERBLOCK_CSUM_XOR));
202}
203
204static int check_metadata_version(struct superblock_disk *disk)
205{
206 uint32_t metadata_version = le32_to_cpu(disk->version);
207 if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) {
208 DMERR("Era metadata version %u found, but only versions between %u and %u supported.",
209 metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION);
210 return -EINVAL;
211 }
212
213 return 0;
214}
215
216static int sb_check(struct dm_block_validator *v,
217 struct dm_block *b,
218 size_t sb_block_size)
219{
220 struct superblock_disk *disk = dm_block_data(b);
221 __le32 csum_le;
222
223 if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) {
224 DMERR("sb_check failed: blocknr %llu: wanted %llu",
225 le64_to_cpu(disk->blocknr),
226 (unsigned long long)dm_block_location(b));
227 return -ENOTBLK;
228 }
229
230 if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) {
231 DMERR("sb_check failed: magic %llu: wanted %llu",
232 le64_to_cpu(disk->magic),
233 (unsigned long long) SUPERBLOCK_MAGIC);
234 return -EILSEQ;
235 }
236
237 csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags,
238 sb_block_size - sizeof(__le32),
239 SUPERBLOCK_CSUM_XOR));
240 if (csum_le != disk->csum) {
241 DMERR("sb_check failed: csum %u: wanted %u",
242 le32_to_cpu(csum_le), le32_to_cpu(disk->csum));
243 return -EILSEQ;
244 }
245
246 return check_metadata_version(disk);
247}
248
249static struct dm_block_validator sb_validator = {
250 .name = "superblock",
251 .prepare_for_write = sb_prepare_for_write,
252 .check = sb_check
253};
254
255/*----------------------------------------------------------------
256 * Low level metadata handling
257 *--------------------------------------------------------------*/
258#define DM_ERA_METADATA_BLOCK_SIZE 4096
259#define ERA_MAX_CONCURRENT_LOCKS 5
260
261struct era_metadata {
262 struct block_device *bdev;
263 struct dm_block_manager *bm;
264 struct dm_space_map *sm;
265 struct dm_transaction_manager *tm;
266
267 dm_block_t block_size;
268 uint32_t nr_blocks;
269
270 uint32_t current_era;
271
272 /*
273 * We preallocate 2 writesets. When an era rolls over we
274 * switch between them. This means the allocation is done at
275 * preresume time, rather than on the io path.
276 */
277 struct writeset writesets[2];
278 struct writeset *current_writeset;
279
280 dm_block_t writeset_tree_root;
281 dm_block_t era_array_root;
282
283 struct dm_disk_bitset bitset_info;
284 struct dm_btree_info writeset_tree_info;
285 struct dm_array_info era_array_info;
286
287 dm_block_t metadata_snap;
288
289 /*
290 * A flag that is set whenever a writeset has been archived.
291 */
292 bool archived_writesets;
293
294 /*
295 * Reading the space map root can fail, so we read it into this
296 * buffer before the superblock is locked and updated.
297 */
298 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
299};
300
301static int superblock_read_lock(struct era_metadata *md,
302 struct dm_block **sblock)
303{
304 return dm_bm_read_lock(md->bm, SUPERBLOCK_LOCATION,
305 &sb_validator, sblock);
306}
307
308static int superblock_lock_zero(struct era_metadata *md,
309 struct dm_block **sblock)
310{
311 return dm_bm_write_lock_zero(md->bm, SUPERBLOCK_LOCATION,
312 &sb_validator, sblock);
313}
314
315static int superblock_lock(struct era_metadata *md,
316 struct dm_block **sblock)
317{
318 return dm_bm_write_lock(md->bm, SUPERBLOCK_LOCATION,
319 &sb_validator, sblock);
320}
321
322/* FIXME: duplication with cache and thin */
323static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
324{
325 int r;
326 unsigned i;
327 struct dm_block *b;
328 __le64 *data_le, zero = cpu_to_le64(0);
329 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
330
331 /*
332 * We can't use a validator here - it may be all zeroes.
333 */
334 r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &b);
335 if (r)
336 return r;
337
338 data_le = dm_block_data(b);
339 *result = true;
340 for (i = 0; i < sb_block_size; i++) {
341 if (data_le[i] != zero) {
342 *result = false;
343 break;
344 }
345 }
346
347 dm_bm_unlock(b);
348
349 return 0;
350}
351
352/*----------------------------------------------------------------*/
353
354static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk)
355{
356 disk->nr_bits = cpu_to_le32(core->nr_bits);
357 disk->root = cpu_to_le64(core->root);
358}
359
360static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core)
361{
362 core->nr_bits = le32_to_cpu(disk->nr_bits);
363 core->root = le64_to_cpu(disk->root);
364}
365
366static void ws_inc(void *context, const void *value, unsigned count)
367{
368 struct era_metadata *md = context;
369 struct writeset_disk ws_d;
370 dm_block_t b;
371 unsigned i;
372
373 for (i = 0; i < count; i++) {
374 memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d));
375 b = le64_to_cpu(ws_d.root);
376 dm_tm_inc(md->tm, b);
377 }
378}
379
380static void ws_dec(void *context, const void *value, unsigned count)
381{
382 struct era_metadata *md = context;
383 struct writeset_disk ws_d;
384 dm_block_t b;
385 unsigned i;
386
387 for (i = 0; i < count; i++) {
388 memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d));
389 b = le64_to_cpu(ws_d.root);
390 dm_bitset_del(&md->bitset_info, b);
391 }
392}
393
394static int ws_eq(void *context, const void *value1, const void *value2)
395{
396 return !memcmp(value1, value2, sizeof(struct writeset_disk));
397}
398
399/*----------------------------------------------------------------*/
400
401static void setup_writeset_tree_info(struct era_metadata *md)
402{
403 struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type;
404 md->writeset_tree_info.tm = md->tm;
405 md->writeset_tree_info.levels = 1;
406 vt->context = md;
407 vt->size = sizeof(struct writeset_disk);
408 vt->inc = ws_inc;
409 vt->dec = ws_dec;
410 vt->equal = ws_eq;
411}
412
413static void setup_era_array_info(struct era_metadata *md)
414
415{
416 struct dm_btree_value_type vt;
417 vt.context = NULL;
418 vt.size = sizeof(__le32);
419 vt.inc = NULL;
420 vt.dec = NULL;
421 vt.equal = NULL;
422
423 dm_array_info_init(&md->era_array_info, md->tm, &vt);
424}
425
426static void setup_infos(struct era_metadata *md)
427{
428 dm_disk_bitset_init(md->tm, &md->bitset_info);
429 setup_writeset_tree_info(md);
430 setup_era_array_info(md);
431}
432
433/*----------------------------------------------------------------*/
434
435static int create_fresh_metadata(struct era_metadata *md)
436{
437 int r;
438
439 r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION,
440 &md->tm, &md->sm);
441 if (r < 0) {
442 DMERR("dm_tm_create_with_sm failed");
443 return r;
444 }
445
446 setup_infos(md);
447
448 r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root);
449 if (r) {
450 DMERR("couldn't create new writeset tree");
451 goto bad;
452 }
453
454 r = dm_array_empty(&md->era_array_info, &md->era_array_root);
455 if (r) {
456 DMERR("couldn't create era array");
457 goto bad;
458 }
459
460 return 0;
461
462bad:
463 dm_sm_destroy(md->sm);
464 dm_tm_destroy(md->tm);
465
466 return r;
467}
468
469static int save_sm_root(struct era_metadata *md)
470{
471 int r;
472 size_t metadata_len;
473
474 r = dm_sm_root_size(md->sm, &metadata_len);
475 if (r < 0)
476 return r;
477
478 return dm_sm_copy_root(md->sm, &md->metadata_space_map_root,
479 metadata_len);
480}
481
482static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk)
483{
484 memcpy(&disk->metadata_space_map_root,
485 &md->metadata_space_map_root,
486 sizeof(md->metadata_space_map_root));
487}
488
489/*
490 * Writes a superblock, including the static fields that don't get updated
491 * with every commit (possible optimisation here). 'md' should be fully
492 * constructed when this is called.
493 */
494static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk)
495{
496 disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
497 disk->flags = cpu_to_le32(0ul);
498
499 /* FIXME: can't keep blanking the uuid (uuid is currently unused though) */
500 memset(disk->uuid, 0, sizeof(disk->uuid));
501 disk->version = cpu_to_le32(MAX_ERA_VERSION);
502
503 copy_sm_root(md, disk);
504
505 disk->data_block_size = cpu_to_le32(md->block_size);
506 disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
507 disk->nr_blocks = cpu_to_le32(md->nr_blocks);
508 disk->current_era = cpu_to_le32(md->current_era);
509
510 ws_pack(&md->current_writeset->md, &disk->current_writeset);
511 disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root);
512 disk->era_array_root = cpu_to_le64(md->era_array_root);
513 disk->metadata_snap = cpu_to_le64(md->metadata_snap);
514}
515
516static int write_superblock(struct era_metadata *md)
517{
518 int r;
519 struct dm_block *sblock;
520 struct superblock_disk *disk;
521
522 r = save_sm_root(md);
523 if (r) {
524 DMERR("%s: save_sm_root failed", __func__);
525 return r;
526 }
527
528 r = superblock_lock_zero(md, &sblock);
529 if (r)
530 return r;
531
532 disk = dm_block_data(sblock);
533 prepare_superblock(md, disk);
534
535 return dm_tm_commit(md->tm, sblock);
536}
537
538/*
539 * Assumes block_size and the infos are set.
540 */
541static int format_metadata(struct era_metadata *md)
542{
543 int r;
544
545 r = create_fresh_metadata(md);
546 if (r)
547 return r;
548
549 r = write_superblock(md);
550 if (r) {
551 dm_sm_destroy(md->sm);
552 dm_tm_destroy(md->tm);
553 return r;
554 }
555
556 return 0;
557}
558
559static int open_metadata(struct era_metadata *md)
560{
561 int r;
562 struct dm_block *sblock;
563 struct superblock_disk *disk;
564
565 r = superblock_read_lock(md, &sblock);
566 if (r) {
567 DMERR("couldn't read_lock superblock");
568 return r;
569 }
570
571 disk = dm_block_data(sblock);
572
573 /* Verify the data block size hasn't changed */
574 if (le32_to_cpu(disk->data_block_size) != md->block_size) {
575 DMERR("changing the data block size (from %u to %llu) is not supported",
576 le32_to_cpu(disk->data_block_size), md->block_size);
577 r = -EINVAL;
578 goto bad;
579 }
580
581 r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION,
582 disk->metadata_space_map_root,
583 sizeof(disk->metadata_space_map_root),
584 &md->tm, &md->sm);
585 if (r) {
586 DMERR("dm_tm_open_with_sm failed");
587 goto bad;
588 }
589
590 setup_infos(md);
591
592 md->nr_blocks = le32_to_cpu(disk->nr_blocks);
593 md->current_era = le32_to_cpu(disk->current_era);
594
595 ws_unpack(&disk->current_writeset, &md->current_writeset->md);
596 md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root);
597 md->era_array_root = le64_to_cpu(disk->era_array_root);
598 md->metadata_snap = le64_to_cpu(disk->metadata_snap);
599 md->archived_writesets = true;
600
601 dm_bm_unlock(sblock);
602
603 return 0;
604
605bad:
606 dm_bm_unlock(sblock);
607 return r;
608}
609
610static int open_or_format_metadata(struct era_metadata *md,
611 bool may_format)
612{
613 int r;
614 bool unformatted = false;
615
616 r = superblock_all_zeroes(md->bm, &unformatted);
617 if (r)
618 return r;
619
620 if (unformatted)
621 return may_format ? format_metadata(md) : -EPERM;
622
623 return open_metadata(md);
624}
625
626static int create_persistent_data_objects(struct era_metadata *md,
627 bool may_format)
628{
629 int r;
630
631 md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE,
632 ERA_MAX_CONCURRENT_LOCKS);
633 if (IS_ERR(md->bm)) {
634 DMERR("could not create block manager");
635 return PTR_ERR(md->bm);
636 }
637
638 r = open_or_format_metadata(md, may_format);
639 if (r)
640 dm_block_manager_destroy(md->bm);
641
642 return r;
643}
644
645static void destroy_persistent_data_objects(struct era_metadata *md)
646{
647 dm_sm_destroy(md->sm);
648 dm_tm_destroy(md->tm);
649 dm_block_manager_destroy(md->bm);
650}
651
652/*
653 * This waits until all era_map threads have picked up the new filter.
654 */
655static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset)
656{
657 rcu_assign_pointer(md->current_writeset, new_writeset);
658 synchronize_rcu();
659}
660
661/*----------------------------------------------------------------
662 * Writesets get 'digested' into the main era array.
663 *
664 * We're using a coroutine here so the worker thread can do the digestion,
665 * thus avoiding synchronisation of the metadata. Digesting a whole
666 * writeset in one go would cause too much latency.
667 *--------------------------------------------------------------*/
668struct digest {
669 uint32_t era;
670 unsigned nr_bits, current_bit;
671 struct writeset_metadata writeset;
672 __le32 value;
673 struct dm_disk_bitset info;
674
675 int (*step)(struct era_metadata *, struct digest *);
676};
677
678static int metadata_digest_lookup_writeset(struct era_metadata *md,
679 struct digest *d);
680
681static int metadata_digest_remove_writeset(struct era_metadata *md,
682 struct digest *d)
683{
684 int r;
685 uint64_t key = d->era;
686
687 r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root,
688 &key, &md->writeset_tree_root);
689 if (r) {
690 DMERR("%s: dm_btree_remove failed", __func__);
691 return r;
692 }
693
694 d->step = metadata_digest_lookup_writeset;
695 return 0;
696}
697
698#define INSERTS_PER_STEP 100
699
700static int metadata_digest_transcribe_writeset(struct era_metadata *md,
701 struct digest *d)
702{
703 int r;
704 bool marked;
705 unsigned b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits);
706
707 for (b = d->current_bit; b < e; b++) {
708 r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked);
709 if (r) {
710 DMERR("%s: writeset_marked_on_disk failed", __func__);
711 return r;
712 }
713
714 if (!marked)
715 continue;
716
717 __dm_bless_for_disk(&d->value);
718 r = dm_array_set_value(&md->era_array_info, md->era_array_root,
719 b, &d->value, &md->era_array_root);
720 if (r) {
721 DMERR("%s: dm_array_set_value failed", __func__);
722 return r;
723 }
724 }
725
726 if (b == d->nr_bits)
727 d->step = metadata_digest_remove_writeset;
728 else
729 d->current_bit = b;
730
731 return 0;
732}
733
734static int metadata_digest_lookup_writeset(struct era_metadata *md,
735 struct digest *d)
736{
737 int r;
738 uint64_t key;
739 struct writeset_disk disk;
740
741 r = dm_btree_find_lowest_key(&md->writeset_tree_info,
742 md->writeset_tree_root, &key);
743 if (r < 0)
744 return r;
745
746 d->era = key;
747
748 r = dm_btree_lookup(&md->writeset_tree_info,
749 md->writeset_tree_root, &key, &disk);
750 if (r) {
751 if (r == -ENODATA) {
752 d->step = NULL;
753 return 0;
754 }
755
756 DMERR("%s: dm_btree_lookup failed", __func__);
757 return r;
758 }
759
760 ws_unpack(&disk, &d->writeset);
761 d->value = cpu_to_le32(key);
762
763 /*
764 * We initialise another bitset info to avoid any caching side effects
765 * with the previous one.
766 */
767 dm_disk_bitset_init(md->tm, &d->info);
768
769 d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks);
770 d->current_bit = 0;
771 d->step = metadata_digest_transcribe_writeset;
772
773 return 0;
774}
775
776static int metadata_digest_start(struct era_metadata *md, struct digest *d)
777{
778 if (d->step)
779 return 0;
780
781 memset(d, 0, sizeof(*d));
782 d->step = metadata_digest_lookup_writeset;
783
784 return 0;
785}
786
787/*----------------------------------------------------------------
788 * High level metadata interface. Target methods should use these, and not
789 * the lower level ones.
790 *--------------------------------------------------------------*/
791static struct era_metadata *metadata_open(struct block_device *bdev,
792 sector_t block_size,
793 bool may_format)
794{
795 int r;
796 struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL);
797
798 if (!md)
799 return NULL;
800
801 md->bdev = bdev;
802 md->block_size = block_size;
803
804 md->writesets[0].md.root = INVALID_WRITESET_ROOT;
805 md->writesets[1].md.root = INVALID_WRITESET_ROOT;
806 md->current_writeset = &md->writesets[0];
807
808 r = create_persistent_data_objects(md, may_format);
809 if (r) {
810 kfree(md);
811 return ERR_PTR(r);
812 }
813
814 return md;
815}
816
817static void metadata_close(struct era_metadata *md)
818{
819 writeset_free(&md->writesets[0]);
820 writeset_free(&md->writesets[1]);
821 destroy_persistent_data_objects(md);
822 kfree(md);
823}
824
825static bool valid_nr_blocks(dm_block_t n)
826{
827 /*
828 * dm_bitset restricts us to 2^32. test_bit & co. restrict us
829 * further to 2^31 - 1
830 */
831 return n < (1ull << 31);
832}
833
834static int metadata_resize(struct era_metadata *md, void *arg)
835{
836 int r;
837 dm_block_t *new_size = arg;
838 __le32 value;
839
840 if (!valid_nr_blocks(*new_size)) {
841 DMERR("Invalid number of origin blocks %llu",
842 (unsigned long long) *new_size);
843 return -EINVAL;
844 }
845
846 writeset_free(&md->writesets[0]);
847 writeset_free(&md->writesets[1]);
848
849 r = writeset_alloc(&md->writesets[0], *new_size);
850 if (r) {
851 DMERR("%s: writeset_alloc failed for writeset 0", __func__);
852 return r;
853 }
854
855 r = writeset_alloc(&md->writesets[1], *new_size);
856 if (r) {
857 DMERR("%s: writeset_alloc failed for writeset 1", __func__);
858 writeset_free(&md->writesets[0]);
859 return r;
860 }
861
862 value = cpu_to_le32(0u);
863 __dm_bless_for_disk(&value);
864 r = dm_array_resize(&md->era_array_info, md->era_array_root,
865 md->nr_blocks, *new_size,
866 &value, &md->era_array_root);
867 if (r) {
868 DMERR("%s: dm_array_resize failed", __func__);
869 writeset_free(&md->writesets[0]);
870 writeset_free(&md->writesets[1]);
871 return r;
872 }
873
874 md->nr_blocks = *new_size;
875 return 0;
876}
877
878static int metadata_era_archive(struct era_metadata *md)
879{
880 int r;
881 uint64_t keys[1];
882 struct writeset_disk value;
883
884 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
885 &md->current_writeset->md.root);
886 if (r) {
887 DMERR("%s: dm_bitset_flush failed", __func__);
888 return r;
889 }
890
891 ws_pack(&md->current_writeset->md, &value);
892
893 keys[0] = md->current_era;
894 __dm_bless_for_disk(&value);
895 r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root,
896 keys, &value, &md->writeset_tree_root);
897 if (r) {
898 DMERR("%s: couldn't insert writeset into btree", __func__);
899 /* FIXME: fail mode */
900 return r;
901 }
902
903 md->current_writeset->md.root = INVALID_WRITESET_ROOT;
904 md->archived_writesets = true;
905
906 return 0;
907}
908
909static struct writeset *next_writeset(struct era_metadata *md)
910{
911 return (md->current_writeset == &md->writesets[0]) ?
912 &md->writesets[1] : &md->writesets[0];
913}
914
915static int metadata_new_era(struct era_metadata *md)
916{
917 int r;
918 struct writeset *new_writeset = next_writeset(md);
919
920 r = writeset_init(&md->bitset_info, new_writeset, md->nr_blocks);
921 if (r) {
922 DMERR("%s: writeset_init failed", __func__);
923 return r;
924 }
925
926 swap_writeset(md, new_writeset);
927 md->current_era++;
928
929 return 0;
930}
931
932static int metadata_era_rollover(struct era_metadata *md)
933{
934 int r;
935
936 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
937 r = metadata_era_archive(md);
938 if (r) {
939 DMERR("%s: metadata_archive_era failed", __func__);
940 /* FIXME: fail mode? */
941 return r;
942 }
943 }
944
945 r = metadata_new_era(md);
946 if (r) {
947 DMERR("%s: new era failed", __func__);
948 /* FIXME: fail mode */
949 return r;
950 }
951
952 return 0;
953}
954
955static bool metadata_current_marked(struct era_metadata *md, dm_block_t block)
956{
957 bool r;
958 struct writeset *ws;
959
960 rcu_read_lock();
961 ws = rcu_dereference(md->current_writeset);
962 r = writeset_marked(ws, block);
963 rcu_read_unlock();
964
965 return r;
966}
967
968static int metadata_commit(struct era_metadata *md)
969{
970 int r;
971 struct dm_block *sblock;
972
973 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
974 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
975 &md->current_writeset->md.root);
976 if (r) {
977 DMERR("%s: bitset flush failed", __func__);
978 return r;
979 }
980 }
981
982 r = dm_tm_pre_commit(md->tm);
983 if (r) {
984 DMERR("%s: pre commit failed", __func__);
985 return r;
986 }
987
988 r = save_sm_root(md);
989 if (r) {
990 DMERR("%s: save_sm_root failed", __func__);
991 return r;
992 }
993
994 r = superblock_lock(md, &sblock);
995 if (r) {
996 DMERR("%s: superblock lock failed", __func__);
997 return r;
998 }
999
1000 prepare_superblock(md, dm_block_data(sblock));
1001
1002 return dm_tm_commit(md->tm, sblock);
1003}
1004
1005static int metadata_checkpoint(struct era_metadata *md)
1006{
1007 /*
1008 * For now we just rollover, but later I want to put a check in to
1009 * avoid this if the filter is still pretty fresh.
1010 */
1011 return metadata_era_rollover(md);
1012}
1013
1014/*
1015 * Metadata snapshots allow userland to access era data.
1016 */
1017static int metadata_take_snap(struct era_metadata *md)
1018{
1019 int r, inc;
1020 struct dm_block *clone;
1021
1022 if (md->metadata_snap != SUPERBLOCK_LOCATION) {
1023 DMERR("%s: metadata snapshot already exists", __func__);
1024 return -EINVAL;
1025 }
1026
1027 r = metadata_era_rollover(md);
1028 if (r) {
1029 DMERR("%s: era rollover failed", __func__);
1030 return r;
1031 }
1032
1033 r = metadata_commit(md);
1034 if (r) {
1035 DMERR("%s: pre commit failed", __func__);
1036 return r;
1037 }
1038
1039 r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION);
1040 if (r) {
1041 DMERR("%s: couldn't increment superblock", __func__);
1042 return r;
1043 }
1044
1045 r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION,
1046 &sb_validator, &clone, &inc);
1047 if (r) {
1048 DMERR("%s: couldn't shadow superblock", __func__);
1049 dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION);
1050 return r;
1051 }
1052 BUG_ON(!inc);
1053
1054 r = dm_sm_inc_block(md->sm, md->writeset_tree_root);
1055 if (r) {
1056 DMERR("%s: couldn't inc writeset tree root", __func__);
1057 dm_tm_unlock(md->tm, clone);
1058 return r;
1059 }
1060
1061 r = dm_sm_inc_block(md->sm, md->era_array_root);
1062 if (r) {
1063 DMERR("%s: couldn't inc era tree root", __func__);
1064 dm_sm_dec_block(md->sm, md->writeset_tree_root);
1065 dm_tm_unlock(md->tm, clone);
1066 return r;
1067 }
1068
1069 md->metadata_snap = dm_block_location(clone);
1070
1071 dm_tm_unlock(md->tm, clone);
1072
1073 return 0;
1074}
1075
1076static int metadata_drop_snap(struct era_metadata *md)
1077{
1078 int r;
1079 dm_block_t location;
1080 struct dm_block *clone;
1081 struct superblock_disk *disk;
1082
1083 if (md->metadata_snap == SUPERBLOCK_LOCATION) {
1084 DMERR("%s: no snap to drop", __func__);
1085 return -EINVAL;
1086 }
1087
1088 r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone);
1089 if (r) {
1090 DMERR("%s: couldn't read lock superblock clone", __func__);
1091 return r;
1092 }
1093
1094 /*
1095 * Whatever happens now we'll commit with no record of the metadata
1096 * snap.
1097 */
1098 md->metadata_snap = SUPERBLOCK_LOCATION;
1099
1100 disk = dm_block_data(clone);
1101 r = dm_btree_del(&md->writeset_tree_info,
1102 le64_to_cpu(disk->writeset_tree_root));
1103 if (r) {
1104 DMERR("%s: error deleting writeset tree clone", __func__);
1105 dm_tm_unlock(md->tm, clone);
1106 return r;
1107 }
1108
1109 r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root));
1110 if (r) {
1111 DMERR("%s: error deleting era array clone", __func__);
1112 dm_tm_unlock(md->tm, clone);
1113 return r;
1114 }
1115
1116 location = dm_block_location(clone);
1117 dm_tm_unlock(md->tm, clone);
1118
1119 return dm_sm_dec_block(md->sm, location);
1120}
1121
1122struct metadata_stats {
1123 dm_block_t used;
1124 dm_block_t total;
1125 dm_block_t snap;
1126 uint32_t era;
1127};
1128
1129static int metadata_get_stats(struct era_metadata *md, void *ptr)
1130{
1131 int r;
1132 struct metadata_stats *s = ptr;
1133 dm_block_t nr_free, nr_total;
1134
1135 r = dm_sm_get_nr_free(md->sm, &nr_free);
1136 if (r) {
1137 DMERR("dm_sm_get_nr_free returned %d", r);
1138 return r;
1139 }
1140
1141 r = dm_sm_get_nr_blocks(md->sm, &nr_total);
1142 if (r) {
1143 DMERR("dm_pool_get_metadata_dev_size returned %d", r);
1144 return r;
1145 }
1146
1147 s->used = nr_total - nr_free;
1148 s->total = nr_total;
1149 s->snap = md->metadata_snap;
1150 s->era = md->current_era;
1151
1152 return 0;
1153}
1154
1155/*----------------------------------------------------------------*/
1156
1157struct era {
1158 struct dm_target *ti;
1159
1160 struct dm_dev *metadata_dev;
1161 struct dm_dev *origin_dev;
1162
1163 dm_block_t nr_blocks;
1164 uint32_t sectors_per_block;
1165 int sectors_per_block_shift;
1166 struct era_metadata *md;
1167
1168 struct workqueue_struct *wq;
1169 struct work_struct worker;
1170
1171 spinlock_t deferred_lock;
1172 struct bio_list deferred_bios;
1173
1174 spinlock_t rpc_lock;
1175 struct list_head rpc_calls;
1176
1177 struct digest digest;
1178 atomic_t suspended;
1179};
1180
1181struct rpc {
1182 struct list_head list;
1183
1184 int (*fn0)(struct era_metadata *);
1185 int (*fn1)(struct era_metadata *, void *);
1186 void *arg;
1187 int result;
1188
1189 struct completion complete;
1190};
1191
1192/*----------------------------------------------------------------
1193 * Remapping.
1194 *---------------------------------------------------------------*/
1195static bool block_size_is_power_of_two(struct era *era)
1196{
1197 return era->sectors_per_block_shift >= 0;
1198}
1199
1200static dm_block_t get_block(struct era *era, struct bio *bio)
1201{
1202 sector_t block_nr = bio->bi_iter.bi_sector;
1203
1204 if (!block_size_is_power_of_two(era))
1205 (void) sector_div(block_nr, era->sectors_per_block);
1206 else
1207 block_nr >>= era->sectors_per_block_shift;
1208
1209 return block_nr;
1210}
1211
1212static void remap_to_origin(struct era *era, struct bio *bio)
1213{
1214 bio_set_dev(bio, era->origin_dev->bdev);
1215}
1216
1217/*----------------------------------------------------------------
1218 * Worker thread
1219 *--------------------------------------------------------------*/
1220static void wake_worker(struct era *era)
1221{
1222 if (!atomic_read(&era->suspended))
1223 queue_work(era->wq, &era->worker);
1224}
1225
1226static void process_old_eras(struct era *era)
1227{
1228 int r;
1229
1230 if (!era->digest.step)
1231 return;
1232
1233 r = era->digest.step(era->md, &era->digest);
1234 if (r < 0) {
1235 DMERR("%s: digest step failed, stopping digestion", __func__);
1236 era->digest.step = NULL;
1237
1238 } else if (era->digest.step)
1239 wake_worker(era);
1240}
1241
1242static void process_deferred_bios(struct era *era)
1243{
1244 int r;
1245 struct bio_list deferred_bios, marked_bios;
1246 struct bio *bio;
1247 struct blk_plug plug;
1248 bool commit_needed = false;
1249 bool failed = false;
1250 struct writeset *ws = era->md->current_writeset;
1251
1252 bio_list_init(&deferred_bios);
1253 bio_list_init(&marked_bios);
1254
1255 spin_lock(&era->deferred_lock);
1256 bio_list_merge(&deferred_bios, &era->deferred_bios);
1257 bio_list_init(&era->deferred_bios);
1258 spin_unlock(&era->deferred_lock);
1259
1260 if (bio_list_empty(&deferred_bios))
1261 return;
1262
1263 while ((bio = bio_list_pop(&deferred_bios))) {
1264 r = writeset_test_and_set(&era->md->bitset_info, ws,
1265 get_block(era, bio));
1266 if (r < 0) {
1267 /*
1268 * This is bad news, we need to rollback.
1269 * FIXME: finish.
1270 */
1271 failed = true;
1272 } else if (r == 0)
1273 commit_needed = true;
1274
1275 bio_list_add(&marked_bios, bio);
1276 }
1277
1278 if (commit_needed) {
1279 r = metadata_commit(era->md);
1280 if (r)
1281 failed = true;
1282 }
1283
1284 if (failed)
1285 while ((bio = bio_list_pop(&marked_bios)))
1286 bio_io_error(bio);
1287 else {
1288 blk_start_plug(&plug);
1289 while ((bio = bio_list_pop(&marked_bios))) {
1290 /*
1291 * Only update the in-core writeset if the on-disk one
1292 * was updated too.
1293 */
1294 if (commit_needed)
1295 set_bit(get_block(era, bio), ws->bits);
1296 submit_bio_noacct(bio);
1297 }
1298 blk_finish_plug(&plug);
1299 }
1300}
1301
1302static void process_rpc_calls(struct era *era)
1303{
1304 int r;
1305 bool need_commit = false;
1306 struct list_head calls;
1307 struct rpc *rpc, *tmp;
1308
1309 INIT_LIST_HEAD(&calls);
1310 spin_lock(&era->rpc_lock);
1311 list_splice_init(&era->rpc_calls, &calls);
1312 spin_unlock(&era->rpc_lock);
1313
1314 list_for_each_entry_safe(rpc, tmp, &calls, list) {
1315 rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg);
1316 need_commit = true;
1317 }
1318
1319 if (need_commit) {
1320 r = metadata_commit(era->md);
1321 if (r)
1322 list_for_each_entry_safe(rpc, tmp, &calls, list)
1323 rpc->result = r;
1324 }
1325
1326 list_for_each_entry_safe(rpc, tmp, &calls, list)
1327 complete(&rpc->complete);
1328}
1329
1330static void kick_off_digest(struct era *era)
1331{
1332 if (era->md->archived_writesets) {
1333 era->md->archived_writesets = false;
1334 metadata_digest_start(era->md, &era->digest);
1335 }
1336}
1337
1338static void do_work(struct work_struct *ws)
1339{
1340 struct era *era = container_of(ws, struct era, worker);
1341
1342 kick_off_digest(era);
1343 process_old_eras(era);
1344 process_deferred_bios(era);
1345 process_rpc_calls(era);
1346}
1347
1348static void defer_bio(struct era *era, struct bio *bio)
1349{
1350 spin_lock(&era->deferred_lock);
1351 bio_list_add(&era->deferred_bios, bio);
1352 spin_unlock(&era->deferred_lock);
1353
1354 wake_worker(era);
1355}
1356
1357/*
1358 * Make an rpc call to the worker to change the metadata.
1359 */
1360static int perform_rpc(struct era *era, struct rpc *rpc)
1361{
1362 rpc->result = 0;
1363 init_completion(&rpc->complete);
1364
1365 spin_lock(&era->rpc_lock);
1366 list_add(&rpc->list, &era->rpc_calls);
1367 spin_unlock(&era->rpc_lock);
1368
1369 wake_worker(era);
1370 wait_for_completion(&rpc->complete);
1371
1372 return rpc->result;
1373}
1374
1375static int in_worker0(struct era *era, int (*fn)(struct era_metadata *))
1376{
1377 struct rpc rpc;
1378 rpc.fn0 = fn;
1379 rpc.fn1 = NULL;
1380
1381 return perform_rpc(era, &rpc);
1382}
1383
1384static int in_worker1(struct era *era,
1385 int (*fn)(struct era_metadata *, void *), void *arg)
1386{
1387 struct rpc rpc;
1388 rpc.fn0 = NULL;
1389 rpc.fn1 = fn;
1390 rpc.arg = arg;
1391
1392 return perform_rpc(era, &rpc);
1393}
1394
1395static void start_worker(struct era *era)
1396{
1397 atomic_set(&era->suspended, 0);
1398}
1399
1400static void stop_worker(struct era *era)
1401{
1402 atomic_set(&era->suspended, 1);
1403 drain_workqueue(era->wq);
1404}
1405
1406/*----------------------------------------------------------------
1407 * Target methods
1408 *--------------------------------------------------------------*/
1409static void era_destroy(struct era *era)
1410{
1411 if (era->md)
1412 metadata_close(era->md);
1413
1414 if (era->wq)
1415 destroy_workqueue(era->wq);
1416
1417 if (era->origin_dev)
1418 dm_put_device(era->ti, era->origin_dev);
1419
1420 if (era->metadata_dev)
1421 dm_put_device(era->ti, era->metadata_dev);
1422
1423 kfree(era);
1424}
1425
1426static dm_block_t calc_nr_blocks(struct era *era)
1427{
1428 return dm_sector_div_up(era->ti->len, era->sectors_per_block);
1429}
1430
1431static bool valid_block_size(dm_block_t block_size)
1432{
1433 bool greater_than_zero = block_size > 0;
1434 bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0;
1435
1436 return greater_than_zero && multiple_of_min_block_size;
1437}
1438
1439/*
1440 * <metadata dev> <data dev> <data block size (sectors)>
1441 */
1442static int era_ctr(struct dm_target *ti, unsigned argc, char **argv)
1443{
1444 int r;
1445 char dummy;
1446 struct era *era;
1447 struct era_metadata *md;
1448
1449 if (argc != 3) {
1450 ti->error = "Invalid argument count";
1451 return -EINVAL;
1452 }
1453
1454 era = kzalloc(sizeof(*era), GFP_KERNEL);
1455 if (!era) {
1456 ti->error = "Error allocating era structure";
1457 return -ENOMEM;
1458 }
1459
1460 era->ti = ti;
1461
1462 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &era->metadata_dev);
1463 if (r) {
1464 ti->error = "Error opening metadata device";
1465 era_destroy(era);
1466 return -EINVAL;
1467 }
1468
1469 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &era->origin_dev);
1470 if (r) {
1471 ti->error = "Error opening data device";
1472 era_destroy(era);
1473 return -EINVAL;
1474 }
1475
1476 r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy);
1477 if (r != 1) {
1478 ti->error = "Error parsing block size";
1479 era_destroy(era);
1480 return -EINVAL;
1481 }
1482
1483 r = dm_set_target_max_io_len(ti, era->sectors_per_block);
1484 if (r) {
1485 ti->error = "could not set max io len";
1486 era_destroy(era);
1487 return -EINVAL;
1488 }
1489
1490 if (!valid_block_size(era->sectors_per_block)) {
1491 ti->error = "Invalid block size";
1492 era_destroy(era);
1493 return -EINVAL;
1494 }
1495 if (era->sectors_per_block & (era->sectors_per_block - 1))
1496 era->sectors_per_block_shift = -1;
1497 else
1498 era->sectors_per_block_shift = __ffs(era->sectors_per_block);
1499
1500 md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true);
1501 if (IS_ERR(md)) {
1502 ti->error = "Error reading metadata";
1503 era_destroy(era);
1504 return PTR_ERR(md);
1505 }
1506 era->md = md;
1507
1508 era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1509 if (!era->wq) {
1510 ti->error = "could not create workqueue for metadata object";
1511 era_destroy(era);
1512 return -ENOMEM;
1513 }
1514 INIT_WORK(&era->worker, do_work);
1515
1516 spin_lock_init(&era->deferred_lock);
1517 bio_list_init(&era->deferred_bios);
1518
1519 spin_lock_init(&era->rpc_lock);
1520 INIT_LIST_HEAD(&era->rpc_calls);
1521
1522 ti->private = era;
1523 ti->num_flush_bios = 1;
1524 ti->flush_supported = true;
1525
1526 ti->num_discard_bios = 1;
1527
1528 return 0;
1529}
1530
1531static void era_dtr(struct dm_target *ti)
1532{
1533 era_destroy(ti->private);
1534}
1535
1536static int era_map(struct dm_target *ti, struct bio *bio)
1537{
1538 struct era *era = ti->private;
1539 dm_block_t block = get_block(era, bio);
1540
1541 /*
1542 * All bios get remapped to the origin device. We do this now, but
1543 * it may not get issued until later. Depending on whether the
1544 * block is marked in this era.
1545 */
1546 remap_to_origin(era, bio);
1547
1548 /*
1549 * REQ_PREFLUSH bios carry no data, so we're not interested in them.
1550 */
1551 if (!(bio->bi_opf & REQ_PREFLUSH) &&
1552 (bio_data_dir(bio) == WRITE) &&
1553 !metadata_current_marked(era->md, block)) {
1554 defer_bio(era, bio);
1555 return DM_MAPIO_SUBMITTED;
1556 }
1557
1558 return DM_MAPIO_REMAPPED;
1559}
1560
1561static void era_postsuspend(struct dm_target *ti)
1562{
1563 int r;
1564 struct era *era = ti->private;
1565
1566 r = in_worker0(era, metadata_era_archive);
1567 if (r) {
1568 DMERR("%s: couldn't archive current era", __func__);
1569 /* FIXME: fail mode */
1570 }
1571
1572 stop_worker(era);
1573
1574 r = metadata_commit(era->md);
1575 if (r) {
1576 DMERR("%s: metadata_commit failed", __func__);
1577 /* FIXME: fail mode */
1578 }
1579}
1580
1581static int era_preresume(struct dm_target *ti)
1582{
1583 int r;
1584 struct era *era = ti->private;
1585 dm_block_t new_size = calc_nr_blocks(era);
1586
1587 if (era->nr_blocks != new_size) {
1588 r = metadata_resize(era->md, &new_size);
1589 if (r) {
1590 DMERR("%s: metadata_resize failed", __func__);
1591 return r;
1592 }
1593
1594 r = metadata_commit(era->md);
1595 if (r) {
1596 DMERR("%s: metadata_commit failed", __func__);
1597 return r;
1598 }
1599
1600 era->nr_blocks = new_size;
1601 }
1602
1603 start_worker(era);
1604
1605 r = in_worker0(era, metadata_era_rollover);
1606 if (r) {
1607 DMERR("%s: metadata_era_rollover failed", __func__);
1608 return r;
1609 }
1610
1611 return 0;
1612}
1613
1614/*
1615 * Status format:
1616 *
1617 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
1618 * <current era> <held metadata root | '-'>
1619 */
1620static void era_status(struct dm_target *ti, status_type_t type,
1621 unsigned status_flags, char *result, unsigned maxlen)
1622{
1623 int r;
1624 struct era *era = ti->private;
1625 ssize_t sz = 0;
1626 struct metadata_stats stats;
1627 char buf[BDEVNAME_SIZE];
1628
1629 switch (type) {
1630 case STATUSTYPE_INFO:
1631 r = in_worker1(era, metadata_get_stats, &stats);
1632 if (r)
1633 goto err;
1634
1635 DMEMIT("%u %llu/%llu %u",
1636 (unsigned) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
1637 (unsigned long long) stats.used,
1638 (unsigned long long) stats.total,
1639 (unsigned) stats.era);
1640
1641 if (stats.snap != SUPERBLOCK_LOCATION)
1642 DMEMIT(" %llu", stats.snap);
1643 else
1644 DMEMIT(" -");
1645 break;
1646
1647 case STATUSTYPE_TABLE:
1648 format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
1649 DMEMIT("%s ", buf);
1650 format_dev_t(buf, era->origin_dev->bdev->bd_dev);
1651 DMEMIT("%s %u", buf, era->sectors_per_block);
1652 break;
1653
1654 case STATUSTYPE_IMA:
1655 *result = '\0';
1656 break;
1657 }
1658
1659 return;
1660
1661err:
1662 DMEMIT("Error");
1663}
1664
1665static int era_message(struct dm_target *ti, unsigned argc, char **argv,
1666 char *result, unsigned maxlen)
1667{
1668 struct era *era = ti->private;
1669
1670 if (argc != 1) {
1671 DMERR("incorrect number of message arguments");
1672 return -EINVAL;
1673 }
1674
1675 if (!strcasecmp(argv[0], "checkpoint"))
1676 return in_worker0(era, metadata_checkpoint);
1677
1678 if (!strcasecmp(argv[0], "take_metadata_snap"))
1679 return in_worker0(era, metadata_take_snap);
1680
1681 if (!strcasecmp(argv[0], "drop_metadata_snap"))
1682 return in_worker0(era, metadata_drop_snap);
1683
1684 DMERR("unsupported message '%s'", argv[0]);
1685 return -EINVAL;
1686}
1687
1688static sector_t get_dev_size(struct dm_dev *dev)
1689{
1690 return bdev_nr_sectors(dev->bdev);
1691}
1692
1693static int era_iterate_devices(struct dm_target *ti,
1694 iterate_devices_callout_fn fn, void *data)
1695{
1696 struct era *era = ti->private;
1697 return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
1698}
1699
1700static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
1701{
1702 struct era *era = ti->private;
1703 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
1704
1705 /*
1706 * If the system-determined stacked limits are compatible with the
1707 * era device's blocksize (io_opt is a factor) do not override them.
1708 */
1709 if (io_opt_sectors < era->sectors_per_block ||
1710 do_div(io_opt_sectors, era->sectors_per_block)) {
1711 blk_limits_io_min(limits, 0);
1712 blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT);
1713 }
1714}
1715
1716/*----------------------------------------------------------------*/
1717
1718static struct target_type era_target = {
1719 .name = "era",
1720 .version = {1, 0, 0},
1721 .module = THIS_MODULE,
1722 .ctr = era_ctr,
1723 .dtr = era_dtr,
1724 .map = era_map,
1725 .postsuspend = era_postsuspend,
1726 .preresume = era_preresume,
1727 .status = era_status,
1728 .message = era_message,
1729 .iterate_devices = era_iterate_devices,
1730 .io_hints = era_io_hints
1731};
1732
1733static int __init dm_era_init(void)
1734{
1735 int r;
1736
1737 r = dm_register_target(&era_target);
1738 if (r) {
1739 DMERR("era target registration failed: %d", r);
1740 return r;
1741 }
1742
1743 return 0;
1744}
1745
1746static void __exit dm_era_exit(void)
1747{
1748 dm_unregister_target(&era_target);
1749}
1750
1751module_init(dm_era_init);
1752module_exit(dm_era_exit);
1753
1754MODULE_DESCRIPTION(DM_NAME " era target");
1755MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
1756MODULE_LICENSE("GPL");
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 struct dm_target_callbacks callbacks;
1141
1142 struct dm_dev *metadata_dev;
1143 struct dm_dev *origin_dev;
1144
1145 dm_block_t nr_blocks;
1146 uint32_t sectors_per_block;
1147 int sectors_per_block_shift;
1148 struct era_metadata *md;
1149
1150 struct workqueue_struct *wq;
1151 struct work_struct worker;
1152
1153 spinlock_t deferred_lock;
1154 struct bio_list deferred_bios;
1155
1156 spinlock_t rpc_lock;
1157 struct list_head rpc_calls;
1158
1159 struct digest digest;
1160 atomic_t suspended;
1161};
1162
1163struct rpc {
1164 struct list_head list;
1165
1166 int (*fn0)(struct era_metadata *);
1167 int (*fn1)(struct era_metadata *, void *);
1168 void *arg;
1169 int result;
1170
1171 struct completion complete;
1172};
1173
1174/*----------------------------------------------------------------
1175 * Remapping.
1176 *---------------------------------------------------------------*/
1177static bool block_size_is_power_of_two(struct era *era)
1178{
1179 return era->sectors_per_block_shift >= 0;
1180}
1181
1182static dm_block_t get_block(struct era *era, struct bio *bio)
1183{
1184 sector_t block_nr = bio->bi_iter.bi_sector;
1185
1186 if (!block_size_is_power_of_two(era))
1187 (void) sector_div(block_nr, era->sectors_per_block);
1188 else
1189 block_nr >>= era->sectors_per_block_shift;
1190
1191 return block_nr;
1192}
1193
1194static void remap_to_origin(struct era *era, struct bio *bio)
1195{
1196 bio_set_dev(bio, era->origin_dev->bdev);
1197}
1198
1199/*----------------------------------------------------------------
1200 * Worker thread
1201 *--------------------------------------------------------------*/
1202static void wake_worker(struct era *era)
1203{
1204 if (!atomic_read(&era->suspended))
1205 queue_work(era->wq, &era->worker);
1206}
1207
1208static void process_old_eras(struct era *era)
1209{
1210 int r;
1211
1212 if (!era->digest.step)
1213 return;
1214
1215 r = era->digest.step(era->md, &era->digest);
1216 if (r < 0) {
1217 DMERR("%s: digest step failed, stopping digestion", __func__);
1218 era->digest.step = NULL;
1219
1220 } else if (era->digest.step)
1221 wake_worker(era);
1222}
1223
1224static void process_deferred_bios(struct era *era)
1225{
1226 int r;
1227 struct bio_list deferred_bios, marked_bios;
1228 struct bio *bio;
1229 bool commit_needed = false;
1230 bool failed = false;
1231
1232 bio_list_init(&deferred_bios);
1233 bio_list_init(&marked_bios);
1234
1235 spin_lock(&era->deferred_lock);
1236 bio_list_merge(&deferred_bios, &era->deferred_bios);
1237 bio_list_init(&era->deferred_bios);
1238 spin_unlock(&era->deferred_lock);
1239
1240 while ((bio = bio_list_pop(&deferred_bios))) {
1241 r = writeset_test_and_set(&era->md->bitset_info,
1242 era->md->current_writeset,
1243 get_block(era, bio));
1244 if (r < 0) {
1245 /*
1246 * This is bad news, we need to rollback.
1247 * FIXME: finish.
1248 */
1249 failed = true;
1250
1251 } else if (r == 0)
1252 commit_needed = true;
1253
1254 bio_list_add(&marked_bios, bio);
1255 }
1256
1257 if (commit_needed) {
1258 r = metadata_commit(era->md);
1259 if (r)
1260 failed = true;
1261 }
1262
1263 if (failed)
1264 while ((bio = bio_list_pop(&marked_bios)))
1265 bio_io_error(bio);
1266 else
1267 while ((bio = bio_list_pop(&marked_bios)))
1268 generic_make_request(bio);
1269}
1270
1271static void process_rpc_calls(struct era *era)
1272{
1273 int r;
1274 bool need_commit = false;
1275 struct list_head calls;
1276 struct rpc *rpc, *tmp;
1277
1278 INIT_LIST_HEAD(&calls);
1279 spin_lock(&era->rpc_lock);
1280 list_splice_init(&era->rpc_calls, &calls);
1281 spin_unlock(&era->rpc_lock);
1282
1283 list_for_each_entry_safe(rpc, tmp, &calls, list) {
1284 rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg);
1285 need_commit = true;
1286 }
1287
1288 if (need_commit) {
1289 r = metadata_commit(era->md);
1290 if (r)
1291 list_for_each_entry_safe(rpc, tmp, &calls, list)
1292 rpc->result = r;
1293 }
1294
1295 list_for_each_entry_safe(rpc, tmp, &calls, list)
1296 complete(&rpc->complete);
1297}
1298
1299static void kick_off_digest(struct era *era)
1300{
1301 if (era->md->archived_writesets) {
1302 era->md->archived_writesets = false;
1303 metadata_digest_start(era->md, &era->digest);
1304 }
1305}
1306
1307static void do_work(struct work_struct *ws)
1308{
1309 struct era *era = container_of(ws, struct era, worker);
1310
1311 kick_off_digest(era);
1312 process_old_eras(era);
1313 process_deferred_bios(era);
1314 process_rpc_calls(era);
1315}
1316
1317static void defer_bio(struct era *era, struct bio *bio)
1318{
1319 spin_lock(&era->deferred_lock);
1320 bio_list_add(&era->deferred_bios, bio);
1321 spin_unlock(&era->deferred_lock);
1322
1323 wake_worker(era);
1324}
1325
1326/*
1327 * Make an rpc call to the worker to change the metadata.
1328 */
1329static int perform_rpc(struct era *era, struct rpc *rpc)
1330{
1331 rpc->result = 0;
1332 init_completion(&rpc->complete);
1333
1334 spin_lock(&era->rpc_lock);
1335 list_add(&rpc->list, &era->rpc_calls);
1336 spin_unlock(&era->rpc_lock);
1337
1338 wake_worker(era);
1339 wait_for_completion(&rpc->complete);
1340
1341 return rpc->result;
1342}
1343
1344static int in_worker0(struct era *era, int (*fn)(struct era_metadata *))
1345{
1346 struct rpc rpc;
1347 rpc.fn0 = fn;
1348 rpc.fn1 = NULL;
1349
1350 return perform_rpc(era, &rpc);
1351}
1352
1353static int in_worker1(struct era *era,
1354 int (*fn)(struct era_metadata *, void *), void *arg)
1355{
1356 struct rpc rpc;
1357 rpc.fn0 = NULL;
1358 rpc.fn1 = fn;
1359 rpc.arg = arg;
1360
1361 return perform_rpc(era, &rpc);
1362}
1363
1364static void start_worker(struct era *era)
1365{
1366 atomic_set(&era->suspended, 0);
1367}
1368
1369static void stop_worker(struct era *era)
1370{
1371 atomic_set(&era->suspended, 1);
1372 flush_workqueue(era->wq);
1373}
1374
1375/*----------------------------------------------------------------
1376 * Target methods
1377 *--------------------------------------------------------------*/
1378static int dev_is_congested(struct dm_dev *dev, int bdi_bits)
1379{
1380 struct request_queue *q = bdev_get_queue(dev->bdev);
1381 return bdi_congested(q->backing_dev_info, bdi_bits);
1382}
1383
1384static int era_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1385{
1386 struct era *era = container_of(cb, struct era, callbacks);
1387 return dev_is_congested(era->origin_dev, bdi_bits);
1388}
1389
1390static void era_destroy(struct era *era)
1391{
1392 if (era->md)
1393 metadata_close(era->md);
1394
1395 if (era->wq)
1396 destroy_workqueue(era->wq);
1397
1398 if (era->origin_dev)
1399 dm_put_device(era->ti, era->origin_dev);
1400
1401 if (era->metadata_dev)
1402 dm_put_device(era->ti, era->metadata_dev);
1403
1404 kfree(era);
1405}
1406
1407static dm_block_t calc_nr_blocks(struct era *era)
1408{
1409 return dm_sector_div_up(era->ti->len, era->sectors_per_block);
1410}
1411
1412static bool valid_block_size(dm_block_t block_size)
1413{
1414 bool greater_than_zero = block_size > 0;
1415 bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0;
1416
1417 return greater_than_zero && multiple_of_min_block_size;
1418}
1419
1420/*
1421 * <metadata dev> <data dev> <data block size (sectors)>
1422 */
1423static int era_ctr(struct dm_target *ti, unsigned argc, char **argv)
1424{
1425 int r;
1426 char dummy;
1427 struct era *era;
1428 struct era_metadata *md;
1429
1430 if (argc != 3) {
1431 ti->error = "Invalid argument count";
1432 return -EINVAL;
1433 }
1434
1435 era = kzalloc(sizeof(*era), GFP_KERNEL);
1436 if (!era) {
1437 ti->error = "Error allocating era structure";
1438 return -ENOMEM;
1439 }
1440
1441 era->ti = ti;
1442
1443 r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &era->metadata_dev);
1444 if (r) {
1445 ti->error = "Error opening metadata device";
1446 era_destroy(era);
1447 return -EINVAL;
1448 }
1449
1450 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &era->origin_dev);
1451 if (r) {
1452 ti->error = "Error opening data device";
1453 era_destroy(era);
1454 return -EINVAL;
1455 }
1456
1457 r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy);
1458 if (r != 1) {
1459 ti->error = "Error parsing block size";
1460 era_destroy(era);
1461 return -EINVAL;
1462 }
1463
1464 r = dm_set_target_max_io_len(ti, era->sectors_per_block);
1465 if (r) {
1466 ti->error = "could not set max io len";
1467 era_destroy(era);
1468 return -EINVAL;
1469 }
1470
1471 if (!valid_block_size(era->sectors_per_block)) {
1472 ti->error = "Invalid block size";
1473 era_destroy(era);
1474 return -EINVAL;
1475 }
1476 if (era->sectors_per_block & (era->sectors_per_block - 1))
1477 era->sectors_per_block_shift = -1;
1478 else
1479 era->sectors_per_block_shift = __ffs(era->sectors_per_block);
1480
1481 md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true);
1482 if (IS_ERR(md)) {
1483 ti->error = "Error reading metadata";
1484 era_destroy(era);
1485 return PTR_ERR(md);
1486 }
1487 era->md = md;
1488
1489 era->nr_blocks = calc_nr_blocks(era);
1490
1491 r = metadata_resize(era->md, &era->nr_blocks);
1492 if (r) {
1493 ti->error = "couldn't resize metadata";
1494 era_destroy(era);
1495 return -ENOMEM;
1496 }
1497
1498 era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1499 if (!era->wq) {
1500 ti->error = "could not create workqueue for metadata object";
1501 era_destroy(era);
1502 return -ENOMEM;
1503 }
1504 INIT_WORK(&era->worker, do_work);
1505
1506 spin_lock_init(&era->deferred_lock);
1507 bio_list_init(&era->deferred_bios);
1508
1509 spin_lock_init(&era->rpc_lock);
1510 INIT_LIST_HEAD(&era->rpc_calls);
1511
1512 ti->private = era;
1513 ti->num_flush_bios = 1;
1514 ti->flush_supported = true;
1515
1516 ti->num_discard_bios = 1;
1517 era->callbacks.congested_fn = era_is_congested;
1518 dm_table_add_target_callbacks(ti->table, &era->callbacks);
1519
1520 return 0;
1521}
1522
1523static void era_dtr(struct dm_target *ti)
1524{
1525 era_destroy(ti->private);
1526}
1527
1528static int era_map(struct dm_target *ti, struct bio *bio)
1529{
1530 struct era *era = ti->private;
1531 dm_block_t block = get_block(era, bio);
1532
1533 /*
1534 * All bios get remapped to the origin device. We do this now, but
1535 * it may not get issued until later. Depending on whether the
1536 * block is marked in this era.
1537 */
1538 remap_to_origin(era, bio);
1539
1540 /*
1541 * REQ_PREFLUSH bios carry no data, so we're not interested in them.
1542 */
1543 if (!(bio->bi_opf & REQ_PREFLUSH) &&
1544 (bio_data_dir(bio) == WRITE) &&
1545 !metadata_current_marked(era->md, block)) {
1546 defer_bio(era, bio);
1547 return DM_MAPIO_SUBMITTED;
1548 }
1549
1550 return DM_MAPIO_REMAPPED;
1551}
1552
1553static void era_postsuspend(struct dm_target *ti)
1554{
1555 int r;
1556 struct era *era = ti->private;
1557
1558 r = in_worker0(era, metadata_era_archive);
1559 if (r) {
1560 DMERR("%s: couldn't archive current era", __func__);
1561 /* FIXME: fail mode */
1562 }
1563
1564 stop_worker(era);
1565}
1566
1567static int era_preresume(struct dm_target *ti)
1568{
1569 int r;
1570 struct era *era = ti->private;
1571 dm_block_t new_size = calc_nr_blocks(era);
1572
1573 if (era->nr_blocks != new_size) {
1574 r = in_worker1(era, metadata_resize, &new_size);
1575 if (r)
1576 return r;
1577
1578 era->nr_blocks = new_size;
1579 }
1580
1581 start_worker(era);
1582
1583 r = in_worker0(era, metadata_new_era);
1584 if (r) {
1585 DMERR("%s: metadata_era_rollover failed", __func__);
1586 return r;
1587 }
1588
1589 return 0;
1590}
1591
1592/*
1593 * Status format:
1594 *
1595 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
1596 * <current era> <held metadata root | '-'>
1597 */
1598static void era_status(struct dm_target *ti, status_type_t type,
1599 unsigned status_flags, char *result, unsigned maxlen)
1600{
1601 int r;
1602 struct era *era = ti->private;
1603 ssize_t sz = 0;
1604 struct metadata_stats stats;
1605 char buf[BDEVNAME_SIZE];
1606
1607 switch (type) {
1608 case STATUSTYPE_INFO:
1609 r = in_worker1(era, metadata_get_stats, &stats);
1610 if (r)
1611 goto err;
1612
1613 DMEMIT("%u %llu/%llu %u",
1614 (unsigned) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
1615 (unsigned long long) stats.used,
1616 (unsigned long long) stats.total,
1617 (unsigned) stats.era);
1618
1619 if (stats.snap != SUPERBLOCK_LOCATION)
1620 DMEMIT(" %llu", stats.snap);
1621 else
1622 DMEMIT(" -");
1623 break;
1624
1625 case STATUSTYPE_TABLE:
1626 format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
1627 DMEMIT("%s ", buf);
1628 format_dev_t(buf, era->origin_dev->bdev->bd_dev);
1629 DMEMIT("%s %u", buf, era->sectors_per_block);
1630 break;
1631 }
1632
1633 return;
1634
1635err:
1636 DMEMIT("Error");
1637}
1638
1639static int era_message(struct dm_target *ti, unsigned argc, char **argv,
1640 char *result, unsigned maxlen)
1641{
1642 struct era *era = ti->private;
1643
1644 if (argc != 1) {
1645 DMERR("incorrect number of message arguments");
1646 return -EINVAL;
1647 }
1648
1649 if (!strcasecmp(argv[0], "checkpoint"))
1650 return in_worker0(era, metadata_checkpoint);
1651
1652 if (!strcasecmp(argv[0], "take_metadata_snap"))
1653 return in_worker0(era, metadata_take_snap);
1654
1655 if (!strcasecmp(argv[0], "drop_metadata_snap"))
1656 return in_worker0(era, metadata_drop_snap);
1657
1658 DMERR("unsupported message '%s'", argv[0]);
1659 return -EINVAL;
1660}
1661
1662static sector_t get_dev_size(struct dm_dev *dev)
1663{
1664 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
1665}
1666
1667static int era_iterate_devices(struct dm_target *ti,
1668 iterate_devices_callout_fn fn, void *data)
1669{
1670 struct era *era = ti->private;
1671 return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
1672}
1673
1674static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
1675{
1676 struct era *era = ti->private;
1677 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
1678
1679 /*
1680 * If the system-determined stacked limits are compatible with the
1681 * era device's blocksize (io_opt is a factor) do not override them.
1682 */
1683 if (io_opt_sectors < era->sectors_per_block ||
1684 do_div(io_opt_sectors, era->sectors_per_block)) {
1685 blk_limits_io_min(limits, 0);
1686 blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT);
1687 }
1688}
1689
1690/*----------------------------------------------------------------*/
1691
1692static struct target_type era_target = {
1693 .name = "era",
1694 .version = {1, 0, 0},
1695 .module = THIS_MODULE,
1696 .ctr = era_ctr,
1697 .dtr = era_dtr,
1698 .map = era_map,
1699 .postsuspend = era_postsuspend,
1700 .preresume = era_preresume,
1701 .status = era_status,
1702 .message = era_message,
1703 .iterate_devices = era_iterate_devices,
1704 .io_hints = era_io_hints
1705};
1706
1707static int __init dm_era_init(void)
1708{
1709 int r;
1710
1711 r = dm_register_target(&era_target);
1712 if (r) {
1713 DMERR("era target registration failed: %d", r);
1714 return r;
1715 }
1716
1717 return 0;
1718}
1719
1720static void __exit dm_era_exit(void)
1721{
1722 dm_unregister_target(&era_target);
1723}
1724
1725module_init(dm_era_init);
1726module_exit(dm_era_exit);
1727
1728MODULE_DESCRIPTION(DM_NAME " era target");
1729MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
1730MODULE_LICENSE("GPL");