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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 *--------------------------------------------------------------
27 * Writeset
28 *--------------------------------------------------------------
29 */
30struct writeset_metadata {
31 uint32_t nr_bits;
32 dm_block_t root;
33};
34
35struct writeset {
36 struct writeset_metadata md;
37
38 /*
39 * An in core copy of the bits to save constantly doing look ups on
40 * disk.
41 */
42 unsigned long *bits;
43};
44
45/*
46 * This does not free off the on disk bitset as this will normally be done
47 * after digesting into the era array.
48 */
49static void writeset_free(struct writeset *ws)
50{
51 vfree(ws->bits);
52 ws->bits = NULL;
53}
54
55static int setup_on_disk_bitset(struct dm_disk_bitset *info,
56 unsigned int nr_bits, dm_block_t *root)
57{
58 int r;
59
60 r = dm_bitset_empty(info, root);
61 if (r)
62 return r;
63
64 return dm_bitset_resize(info, *root, 0, nr_bits, false, root);
65}
66
67static size_t bitset_size(unsigned int nr_bits)
68{
69 return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG);
70}
71
72/*
73 * Allocates memory for the in core bitset.
74 */
75static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks)
76{
77 ws->bits = vzalloc(bitset_size(nr_blocks));
78 if (!ws->bits) {
79 DMERR("%s: couldn't allocate in memory bitset", __func__);
80 return -ENOMEM;
81 }
82
83 return 0;
84}
85
86/*
87 * Wipes the in-core bitset, and creates a new on disk bitset.
88 */
89static int writeset_init(struct dm_disk_bitset *info, struct writeset *ws,
90 dm_block_t nr_blocks)
91{
92 int r;
93
94 memset(ws->bits, 0, bitset_size(nr_blocks));
95
96 ws->md.nr_bits = nr_blocks;
97 r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root);
98 if (r) {
99 DMERR("%s: setup_on_disk_bitset failed", __func__);
100 return r;
101 }
102
103 return 0;
104}
105
106static bool writeset_marked(struct writeset *ws, dm_block_t block)
107{
108 return test_bit(block, ws->bits);
109}
110
111static int writeset_marked_on_disk(struct dm_disk_bitset *info,
112 struct writeset_metadata *m, dm_block_t block,
113 bool *result)
114{
115 int r;
116 dm_block_t old = m->root;
117
118 /*
119 * The bitset was flushed when it was archived, so we know there'll
120 * be no change to the root.
121 */
122 r = dm_bitset_test_bit(info, m->root, block, &m->root, result);
123 if (r) {
124 DMERR("%s: dm_bitset_test_bit failed", __func__);
125 return r;
126 }
127
128 BUG_ON(m->root != old);
129
130 return r;
131}
132
133/*
134 * Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was.
135 */
136static int writeset_test_and_set(struct dm_disk_bitset *info,
137 struct writeset *ws, uint32_t block)
138{
139 int r;
140
141 if (!test_bit(block, ws->bits)) {
142 r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root);
143 if (r) {
144 /* FIXME: fail mode */
145 return r;
146 }
147
148 return 0;
149 }
150
151 return 1;
152}
153
154/*
155 *--------------------------------------------------------------
156 * On disk metadata layout
157 *--------------------------------------------------------------
158 */
159#define SPACE_MAP_ROOT_SIZE 128
160#define UUID_LEN 16
161
162struct writeset_disk {
163 __le32 nr_bits;
164 __le64 root;
165} __packed;
166
167struct superblock_disk {
168 __le32 csum;
169 __le32 flags;
170 __le64 blocknr;
171
172 __u8 uuid[UUID_LEN];
173 __le64 magic;
174 __le32 version;
175
176 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
177
178 __le32 data_block_size;
179 __le32 metadata_block_size;
180 __le32 nr_blocks;
181
182 __le32 current_era;
183 struct writeset_disk current_writeset;
184
185 /*
186 * Only these two fields are valid within the metadata snapshot.
187 */
188 __le64 writeset_tree_root;
189 __le64 era_array_root;
190
191 __le64 metadata_snap;
192} __packed;
193
194/*
195 *--------------------------------------------------------------
196 * Superblock validation
197 *--------------------------------------------------------------
198 */
199static void sb_prepare_for_write(struct dm_block_validator *v,
200 struct dm_block *b,
201 size_t sb_block_size)
202{
203 struct superblock_disk *disk = dm_block_data(b);
204
205 disk->blocknr = cpu_to_le64(dm_block_location(b));
206 disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags,
207 sb_block_size - sizeof(__le32),
208 SUPERBLOCK_CSUM_XOR));
209}
210
211static int check_metadata_version(struct superblock_disk *disk)
212{
213 uint32_t metadata_version = le32_to_cpu(disk->version);
214
215 if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) {
216 DMERR("Era metadata version %u found, but only versions between %u and %u supported.",
217 metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION);
218 return -EINVAL;
219 }
220
221 return 0;
222}
223
224static int sb_check(struct dm_block_validator *v,
225 struct dm_block *b,
226 size_t sb_block_size)
227{
228 struct superblock_disk *disk = dm_block_data(b);
229 __le32 csum_le;
230
231 if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) {
232 DMERR("%s failed: blocknr %llu: wanted %llu",
233 __func__, le64_to_cpu(disk->blocknr),
234 (unsigned long long)dm_block_location(b));
235 return -ENOTBLK;
236 }
237
238 if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) {
239 DMERR("%s failed: magic %llu: wanted %llu",
240 __func__, le64_to_cpu(disk->magic),
241 (unsigned long long) SUPERBLOCK_MAGIC);
242 return -EILSEQ;
243 }
244
245 csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags,
246 sb_block_size - sizeof(__le32),
247 SUPERBLOCK_CSUM_XOR));
248 if (csum_le != disk->csum) {
249 DMERR("%s failed: csum %u: wanted %u",
250 __func__, le32_to_cpu(csum_le), le32_to_cpu(disk->csum));
251 return -EILSEQ;
252 }
253
254 return check_metadata_version(disk);
255}
256
257static struct dm_block_validator sb_validator = {
258 .name = "superblock",
259 .prepare_for_write = sb_prepare_for_write,
260 .check = sb_check
261};
262
263/*
264 *--------------------------------------------------------------
265 * Low level metadata handling
266 *--------------------------------------------------------------
267 */
268#define DM_ERA_METADATA_BLOCK_SIZE 4096
269#define ERA_MAX_CONCURRENT_LOCKS 5
270
271struct era_metadata {
272 struct block_device *bdev;
273 struct dm_block_manager *bm;
274 struct dm_space_map *sm;
275 struct dm_transaction_manager *tm;
276
277 dm_block_t block_size;
278 uint32_t nr_blocks;
279
280 uint32_t current_era;
281
282 /*
283 * We preallocate 2 writesets. When an era rolls over we
284 * switch between them. This means the allocation is done at
285 * preresume time, rather than on the io path.
286 */
287 struct writeset writesets[2];
288 struct writeset *current_writeset;
289
290 dm_block_t writeset_tree_root;
291 dm_block_t era_array_root;
292
293 struct dm_disk_bitset bitset_info;
294 struct dm_btree_info writeset_tree_info;
295 struct dm_array_info era_array_info;
296
297 dm_block_t metadata_snap;
298
299 /*
300 * A flag that is set whenever a writeset has been archived.
301 */
302 bool archived_writesets;
303
304 /*
305 * Reading the space map root can fail, so we read it into this
306 * buffer before the superblock is locked and updated.
307 */
308 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
309};
310
311static int superblock_read_lock(struct era_metadata *md,
312 struct dm_block **sblock)
313{
314 return dm_bm_read_lock(md->bm, SUPERBLOCK_LOCATION,
315 &sb_validator, sblock);
316}
317
318static int superblock_lock_zero(struct era_metadata *md,
319 struct dm_block **sblock)
320{
321 return dm_bm_write_lock_zero(md->bm, SUPERBLOCK_LOCATION,
322 &sb_validator, sblock);
323}
324
325static int superblock_lock(struct era_metadata *md,
326 struct dm_block **sblock)
327{
328 return dm_bm_write_lock(md->bm, SUPERBLOCK_LOCATION,
329 &sb_validator, sblock);
330}
331
332/* FIXME: duplication with cache and thin */
333static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
334{
335 int r;
336 unsigned int i;
337 struct dm_block *b;
338 __le64 *data_le, zero = cpu_to_le64(0);
339 unsigned int sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
340
341 /*
342 * We can't use a validator here - it may be all zeroes.
343 */
344 r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &b);
345 if (r)
346 return r;
347
348 data_le = dm_block_data(b);
349 *result = true;
350 for (i = 0; i < sb_block_size; i++) {
351 if (data_le[i] != zero) {
352 *result = false;
353 break;
354 }
355 }
356
357 dm_bm_unlock(b);
358
359 return 0;
360}
361
362/*----------------------------------------------------------------*/
363
364static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk)
365{
366 disk->nr_bits = cpu_to_le32(core->nr_bits);
367 disk->root = cpu_to_le64(core->root);
368}
369
370static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core)
371{
372 core->nr_bits = le32_to_cpu(disk->nr_bits);
373 core->root = le64_to_cpu(disk->root);
374}
375
376static void ws_inc(void *context, const void *value, unsigned int count)
377{
378 struct era_metadata *md = context;
379 struct writeset_disk ws_d;
380 dm_block_t b;
381 unsigned int i;
382
383 for (i = 0; i < count; i++) {
384 memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d));
385 b = le64_to_cpu(ws_d.root);
386 dm_tm_inc(md->tm, b);
387 }
388}
389
390static void ws_dec(void *context, const void *value, unsigned int count)
391{
392 struct era_metadata *md = context;
393 struct writeset_disk ws_d;
394 dm_block_t b;
395 unsigned int i;
396
397 for (i = 0; i < count; i++) {
398 memcpy(&ws_d, value + (i * sizeof(ws_d)), sizeof(ws_d));
399 b = le64_to_cpu(ws_d.root);
400 dm_bitset_del(&md->bitset_info, b);
401 }
402}
403
404static int ws_eq(void *context, const void *value1, const void *value2)
405{
406 return !memcmp(value1, value2, sizeof(struct writeset_disk));
407}
408
409/*----------------------------------------------------------------*/
410
411static void setup_writeset_tree_info(struct era_metadata *md)
412{
413 struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type;
414
415 md->writeset_tree_info.tm = md->tm;
416 md->writeset_tree_info.levels = 1;
417 vt->context = md;
418 vt->size = sizeof(struct writeset_disk);
419 vt->inc = ws_inc;
420 vt->dec = ws_dec;
421 vt->equal = ws_eq;
422}
423
424static void setup_era_array_info(struct era_metadata *md)
425{
426 struct dm_btree_value_type vt;
427
428 vt.context = NULL;
429 vt.size = sizeof(__le32);
430 vt.inc = NULL;
431 vt.dec = NULL;
432 vt.equal = NULL;
433
434 dm_array_info_init(&md->era_array_info, md->tm, &vt);
435}
436
437static void setup_infos(struct era_metadata *md)
438{
439 dm_disk_bitset_init(md->tm, &md->bitset_info);
440 setup_writeset_tree_info(md);
441 setup_era_array_info(md);
442}
443
444/*----------------------------------------------------------------*/
445
446static int create_fresh_metadata(struct era_metadata *md)
447{
448 int r;
449
450 r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION,
451 &md->tm, &md->sm);
452 if (r < 0) {
453 DMERR("dm_tm_create_with_sm failed");
454 return r;
455 }
456
457 setup_infos(md);
458
459 r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root);
460 if (r) {
461 DMERR("couldn't create new writeset tree");
462 goto bad;
463 }
464
465 r = dm_array_empty(&md->era_array_info, &md->era_array_root);
466 if (r) {
467 DMERR("couldn't create era array");
468 goto bad;
469 }
470
471 return 0;
472
473bad:
474 dm_sm_destroy(md->sm);
475 dm_tm_destroy(md->tm);
476
477 return r;
478}
479
480static int save_sm_root(struct era_metadata *md)
481{
482 int r;
483 size_t metadata_len;
484
485 r = dm_sm_root_size(md->sm, &metadata_len);
486 if (r < 0)
487 return r;
488
489 return dm_sm_copy_root(md->sm, &md->metadata_space_map_root,
490 metadata_len);
491}
492
493static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk)
494{
495 memcpy(&disk->metadata_space_map_root,
496 &md->metadata_space_map_root,
497 sizeof(md->metadata_space_map_root));
498}
499
500/*
501 * Writes a superblock, including the static fields that don't get updated
502 * with every commit (possible optimisation here). 'md' should be fully
503 * constructed when this is called.
504 */
505static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk)
506{
507 disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
508 disk->flags = cpu_to_le32(0ul);
509
510 /* FIXME: can't keep blanking the uuid (uuid is currently unused though) */
511 memset(disk->uuid, 0, sizeof(disk->uuid));
512 disk->version = cpu_to_le32(MAX_ERA_VERSION);
513
514 copy_sm_root(md, disk);
515
516 disk->data_block_size = cpu_to_le32(md->block_size);
517 disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
518 disk->nr_blocks = cpu_to_le32(md->nr_blocks);
519 disk->current_era = cpu_to_le32(md->current_era);
520
521 ws_pack(&md->current_writeset->md, &disk->current_writeset);
522 disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root);
523 disk->era_array_root = cpu_to_le64(md->era_array_root);
524 disk->metadata_snap = cpu_to_le64(md->metadata_snap);
525}
526
527static int write_superblock(struct era_metadata *md)
528{
529 int r;
530 struct dm_block *sblock;
531 struct superblock_disk *disk;
532
533 r = save_sm_root(md);
534 if (r) {
535 DMERR("%s: save_sm_root failed", __func__);
536 return r;
537 }
538
539 r = superblock_lock_zero(md, &sblock);
540 if (r)
541 return r;
542
543 disk = dm_block_data(sblock);
544 prepare_superblock(md, disk);
545
546 return dm_tm_commit(md->tm, sblock);
547}
548
549/*
550 * Assumes block_size and the infos are set.
551 */
552static int format_metadata(struct era_metadata *md)
553{
554 int r;
555
556 r = create_fresh_metadata(md);
557 if (r)
558 return r;
559
560 r = write_superblock(md);
561 if (r) {
562 dm_sm_destroy(md->sm);
563 dm_tm_destroy(md->tm);
564 return r;
565 }
566
567 return 0;
568}
569
570static int open_metadata(struct era_metadata *md)
571{
572 int r;
573 struct dm_block *sblock;
574 struct superblock_disk *disk;
575
576 r = superblock_read_lock(md, &sblock);
577 if (r) {
578 DMERR("couldn't read_lock superblock");
579 return r;
580 }
581
582 disk = dm_block_data(sblock);
583
584 /* Verify the data block size hasn't changed */
585 if (le32_to_cpu(disk->data_block_size) != md->block_size) {
586 DMERR("changing the data block size (from %u to %llu) is not supported",
587 le32_to_cpu(disk->data_block_size), md->block_size);
588 r = -EINVAL;
589 goto bad;
590 }
591
592 r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION,
593 disk->metadata_space_map_root,
594 sizeof(disk->metadata_space_map_root),
595 &md->tm, &md->sm);
596 if (r) {
597 DMERR("dm_tm_open_with_sm failed");
598 goto bad;
599 }
600
601 setup_infos(md);
602
603 md->nr_blocks = le32_to_cpu(disk->nr_blocks);
604 md->current_era = le32_to_cpu(disk->current_era);
605
606 ws_unpack(&disk->current_writeset, &md->current_writeset->md);
607 md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root);
608 md->era_array_root = le64_to_cpu(disk->era_array_root);
609 md->metadata_snap = le64_to_cpu(disk->metadata_snap);
610 md->archived_writesets = true;
611
612 dm_bm_unlock(sblock);
613
614 return 0;
615
616bad:
617 dm_bm_unlock(sblock);
618 return r;
619}
620
621static int open_or_format_metadata(struct era_metadata *md,
622 bool may_format)
623{
624 int r;
625 bool unformatted = false;
626
627 r = superblock_all_zeroes(md->bm, &unformatted);
628 if (r)
629 return r;
630
631 if (unformatted)
632 return may_format ? format_metadata(md) : -EPERM;
633
634 return open_metadata(md);
635}
636
637static int create_persistent_data_objects(struct era_metadata *md,
638 bool may_format)
639{
640 int r;
641
642 md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE,
643 ERA_MAX_CONCURRENT_LOCKS);
644 if (IS_ERR(md->bm)) {
645 DMERR("could not create block manager");
646 return PTR_ERR(md->bm);
647 }
648
649 r = open_or_format_metadata(md, may_format);
650 if (r)
651 dm_block_manager_destroy(md->bm);
652
653 return r;
654}
655
656static void destroy_persistent_data_objects(struct era_metadata *md)
657{
658 dm_sm_destroy(md->sm);
659 dm_tm_destroy(md->tm);
660 dm_block_manager_destroy(md->bm);
661}
662
663/*
664 * This waits until all era_map threads have picked up the new filter.
665 */
666static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset)
667{
668 rcu_assign_pointer(md->current_writeset, new_writeset);
669 synchronize_rcu();
670}
671
672/*
673 *------------------------------------------------------------------------
674 * Writesets get 'digested' into the main era array.
675 *
676 * We're using a coroutine here so the worker thread can do the digestion,
677 * thus avoiding synchronisation of the metadata. Digesting a whole
678 * writeset in one go would cause too much latency.
679 *------------------------------------------------------------------------
680 */
681struct digest {
682 uint32_t era;
683 unsigned int nr_bits, current_bit;
684 struct writeset_metadata writeset;
685 __le32 value;
686 struct dm_disk_bitset info;
687
688 int (*step)(struct era_metadata *md, struct digest *d);
689};
690
691static int metadata_digest_lookup_writeset(struct era_metadata *md,
692 struct digest *d);
693
694static int metadata_digest_remove_writeset(struct era_metadata *md,
695 struct digest *d)
696{
697 int r;
698 uint64_t key = d->era;
699
700 r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root,
701 &key, &md->writeset_tree_root);
702 if (r) {
703 DMERR("%s: dm_btree_remove failed", __func__);
704 return r;
705 }
706
707 d->step = metadata_digest_lookup_writeset;
708 return 0;
709}
710
711#define INSERTS_PER_STEP 100
712
713static int metadata_digest_transcribe_writeset(struct era_metadata *md,
714 struct digest *d)
715{
716 int r;
717 bool marked;
718 unsigned int b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits);
719
720 for (b = d->current_bit; b < e; b++) {
721 r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked);
722 if (r) {
723 DMERR("%s: writeset_marked_on_disk failed", __func__);
724 return r;
725 }
726
727 if (!marked)
728 continue;
729
730 __dm_bless_for_disk(&d->value);
731 r = dm_array_set_value(&md->era_array_info, md->era_array_root,
732 b, &d->value, &md->era_array_root);
733 if (r) {
734 DMERR("%s: dm_array_set_value failed", __func__);
735 return r;
736 }
737 }
738
739 if (b == d->nr_bits)
740 d->step = metadata_digest_remove_writeset;
741 else
742 d->current_bit = b;
743
744 return 0;
745}
746
747static int metadata_digest_lookup_writeset(struct era_metadata *md,
748 struct digest *d)
749{
750 int r;
751 uint64_t key;
752 struct writeset_disk disk;
753
754 r = dm_btree_find_lowest_key(&md->writeset_tree_info,
755 md->writeset_tree_root, &key);
756 if (r < 0)
757 return r;
758
759 d->era = key;
760
761 r = dm_btree_lookup(&md->writeset_tree_info,
762 md->writeset_tree_root, &key, &disk);
763 if (r) {
764 if (r == -ENODATA) {
765 d->step = NULL;
766 return 0;
767 }
768
769 DMERR("%s: dm_btree_lookup failed", __func__);
770 return r;
771 }
772
773 ws_unpack(&disk, &d->writeset);
774 d->value = cpu_to_le32(key);
775
776 /*
777 * We initialise another bitset info to avoid any caching side effects
778 * with the previous one.
779 */
780 dm_disk_bitset_init(md->tm, &d->info);
781
782 d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks);
783 d->current_bit = 0;
784 d->step = metadata_digest_transcribe_writeset;
785
786 return 0;
787}
788
789static int metadata_digest_start(struct era_metadata *md, struct digest *d)
790{
791 if (d->step)
792 return 0;
793
794 memset(d, 0, sizeof(*d));
795 d->step = metadata_digest_lookup_writeset;
796
797 return 0;
798}
799
800/*
801 *-----------------------------------------------------------------
802 * High level metadata interface. Target methods should use these,
803 * and not the lower level ones.
804 *-----------------------------------------------------------------
805 */
806static struct era_metadata *metadata_open(struct block_device *bdev,
807 sector_t block_size,
808 bool may_format)
809{
810 int r;
811 struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL);
812
813 if (!md)
814 return NULL;
815
816 md->bdev = bdev;
817 md->block_size = block_size;
818
819 md->writesets[0].md.root = INVALID_WRITESET_ROOT;
820 md->writesets[1].md.root = INVALID_WRITESET_ROOT;
821 md->current_writeset = &md->writesets[0];
822
823 r = create_persistent_data_objects(md, may_format);
824 if (r) {
825 kfree(md);
826 return ERR_PTR(r);
827 }
828
829 return md;
830}
831
832static void metadata_close(struct era_metadata *md)
833{
834 writeset_free(&md->writesets[0]);
835 writeset_free(&md->writesets[1]);
836 destroy_persistent_data_objects(md);
837 kfree(md);
838}
839
840static bool valid_nr_blocks(dm_block_t n)
841{
842 /*
843 * dm_bitset restricts us to 2^32. test_bit & co. restrict us
844 * further to 2^31 - 1
845 */
846 return n < (1ull << 31);
847}
848
849static int metadata_resize(struct era_metadata *md, void *arg)
850{
851 int r;
852 dm_block_t *new_size = arg;
853 __le32 value;
854
855 if (!valid_nr_blocks(*new_size)) {
856 DMERR("Invalid number of origin blocks %llu",
857 (unsigned long long) *new_size);
858 return -EINVAL;
859 }
860
861 writeset_free(&md->writesets[0]);
862 writeset_free(&md->writesets[1]);
863
864 r = writeset_alloc(&md->writesets[0], *new_size);
865 if (r) {
866 DMERR("%s: writeset_alloc failed for writeset 0", __func__);
867 return r;
868 }
869
870 r = writeset_alloc(&md->writesets[1], *new_size);
871 if (r) {
872 DMERR("%s: writeset_alloc failed for writeset 1", __func__);
873 writeset_free(&md->writesets[0]);
874 return r;
875 }
876
877 value = cpu_to_le32(0u);
878 __dm_bless_for_disk(&value);
879 r = dm_array_resize(&md->era_array_info, md->era_array_root,
880 md->nr_blocks, *new_size,
881 &value, &md->era_array_root);
882 if (r) {
883 DMERR("%s: dm_array_resize failed", __func__);
884 writeset_free(&md->writesets[0]);
885 writeset_free(&md->writesets[1]);
886 return r;
887 }
888
889 md->nr_blocks = *new_size;
890 return 0;
891}
892
893static int metadata_era_archive(struct era_metadata *md)
894{
895 int r;
896 uint64_t keys[1];
897 struct writeset_disk value;
898
899 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
900 &md->current_writeset->md.root);
901 if (r) {
902 DMERR("%s: dm_bitset_flush failed", __func__);
903 return r;
904 }
905
906 ws_pack(&md->current_writeset->md, &value);
907
908 keys[0] = md->current_era;
909 __dm_bless_for_disk(&value);
910 r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root,
911 keys, &value, &md->writeset_tree_root);
912 if (r) {
913 DMERR("%s: couldn't insert writeset into btree", __func__);
914 /* FIXME: fail mode */
915 return r;
916 }
917
918 md->current_writeset->md.root = INVALID_WRITESET_ROOT;
919 md->archived_writesets = true;
920
921 return 0;
922}
923
924static struct writeset *next_writeset(struct era_metadata *md)
925{
926 return (md->current_writeset == &md->writesets[0]) ?
927 &md->writesets[1] : &md->writesets[0];
928}
929
930static int metadata_new_era(struct era_metadata *md)
931{
932 int r;
933 struct writeset *new_writeset = next_writeset(md);
934
935 r = writeset_init(&md->bitset_info, new_writeset, md->nr_blocks);
936 if (r) {
937 DMERR("%s: writeset_init failed", __func__);
938 return r;
939 }
940
941 swap_writeset(md, new_writeset);
942 md->current_era++;
943
944 return 0;
945}
946
947static int metadata_era_rollover(struct era_metadata *md)
948{
949 int r;
950
951 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
952 r = metadata_era_archive(md);
953 if (r) {
954 DMERR("%s: metadata_archive_era failed", __func__);
955 /* FIXME: fail mode? */
956 return r;
957 }
958 }
959
960 r = metadata_new_era(md);
961 if (r) {
962 DMERR("%s: new era failed", __func__);
963 /* FIXME: fail mode */
964 return r;
965 }
966
967 return 0;
968}
969
970static bool metadata_current_marked(struct era_metadata *md, dm_block_t block)
971{
972 bool r;
973 struct writeset *ws;
974
975 rcu_read_lock();
976 ws = rcu_dereference(md->current_writeset);
977 r = writeset_marked(ws, block);
978 rcu_read_unlock();
979
980 return r;
981}
982
983static int metadata_commit(struct era_metadata *md)
984{
985 int r;
986 struct dm_block *sblock;
987
988 if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
989 r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
990 &md->current_writeset->md.root);
991 if (r) {
992 DMERR("%s: bitset flush failed", __func__);
993 return r;
994 }
995 }
996
997 r = dm_tm_pre_commit(md->tm);
998 if (r) {
999 DMERR("%s: pre commit failed", __func__);
1000 return r;
1001 }
1002
1003 r = save_sm_root(md);
1004 if (r) {
1005 DMERR("%s: save_sm_root failed", __func__);
1006 return r;
1007 }
1008
1009 r = superblock_lock(md, &sblock);
1010 if (r) {
1011 DMERR("%s: superblock lock failed", __func__);
1012 return r;
1013 }
1014
1015 prepare_superblock(md, dm_block_data(sblock));
1016
1017 return dm_tm_commit(md->tm, sblock);
1018}
1019
1020static int metadata_checkpoint(struct era_metadata *md)
1021{
1022 /*
1023 * For now we just rollover, but later I want to put a check in to
1024 * avoid this if the filter is still pretty fresh.
1025 */
1026 return metadata_era_rollover(md);
1027}
1028
1029/*
1030 * Metadata snapshots allow userland to access era data.
1031 */
1032static int metadata_take_snap(struct era_metadata *md)
1033{
1034 int r, inc;
1035 struct dm_block *clone;
1036
1037 if (md->metadata_snap != SUPERBLOCK_LOCATION) {
1038 DMERR("%s: metadata snapshot already exists", __func__);
1039 return -EINVAL;
1040 }
1041
1042 r = metadata_era_rollover(md);
1043 if (r) {
1044 DMERR("%s: era rollover failed", __func__);
1045 return r;
1046 }
1047
1048 r = metadata_commit(md);
1049 if (r) {
1050 DMERR("%s: pre commit failed", __func__);
1051 return r;
1052 }
1053
1054 r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION);
1055 if (r) {
1056 DMERR("%s: couldn't increment superblock", __func__);
1057 return r;
1058 }
1059
1060 r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION,
1061 &sb_validator, &clone, &inc);
1062 if (r) {
1063 DMERR("%s: couldn't shadow superblock", __func__);
1064 dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION);
1065 return r;
1066 }
1067 BUG_ON(!inc);
1068
1069 r = dm_sm_inc_block(md->sm, md->writeset_tree_root);
1070 if (r) {
1071 DMERR("%s: couldn't inc writeset tree root", __func__);
1072 dm_tm_unlock(md->tm, clone);
1073 return r;
1074 }
1075
1076 r = dm_sm_inc_block(md->sm, md->era_array_root);
1077 if (r) {
1078 DMERR("%s: couldn't inc era tree root", __func__);
1079 dm_sm_dec_block(md->sm, md->writeset_tree_root);
1080 dm_tm_unlock(md->tm, clone);
1081 return r;
1082 }
1083
1084 md->metadata_snap = dm_block_location(clone);
1085
1086 dm_tm_unlock(md->tm, clone);
1087
1088 return 0;
1089}
1090
1091static int metadata_drop_snap(struct era_metadata *md)
1092{
1093 int r;
1094 dm_block_t location;
1095 struct dm_block *clone;
1096 struct superblock_disk *disk;
1097
1098 if (md->metadata_snap == SUPERBLOCK_LOCATION) {
1099 DMERR("%s: no snap to drop", __func__);
1100 return -EINVAL;
1101 }
1102
1103 r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone);
1104 if (r) {
1105 DMERR("%s: couldn't read lock superblock clone", __func__);
1106 return r;
1107 }
1108
1109 /*
1110 * Whatever happens now we'll commit with no record of the metadata
1111 * snap.
1112 */
1113 md->metadata_snap = SUPERBLOCK_LOCATION;
1114
1115 disk = dm_block_data(clone);
1116 r = dm_btree_del(&md->writeset_tree_info,
1117 le64_to_cpu(disk->writeset_tree_root));
1118 if (r) {
1119 DMERR("%s: error deleting writeset tree clone", __func__);
1120 dm_tm_unlock(md->tm, clone);
1121 return r;
1122 }
1123
1124 r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root));
1125 if (r) {
1126 DMERR("%s: error deleting era array clone", __func__);
1127 dm_tm_unlock(md->tm, clone);
1128 return r;
1129 }
1130
1131 location = dm_block_location(clone);
1132 dm_tm_unlock(md->tm, clone);
1133
1134 return dm_sm_dec_block(md->sm, location);
1135}
1136
1137struct metadata_stats {
1138 dm_block_t used;
1139 dm_block_t total;
1140 dm_block_t snap;
1141 uint32_t era;
1142};
1143
1144static int metadata_get_stats(struct era_metadata *md, void *ptr)
1145{
1146 int r;
1147 struct metadata_stats *s = ptr;
1148 dm_block_t nr_free, nr_total;
1149
1150 r = dm_sm_get_nr_free(md->sm, &nr_free);
1151 if (r) {
1152 DMERR("dm_sm_get_nr_free returned %d", r);
1153 return r;
1154 }
1155
1156 r = dm_sm_get_nr_blocks(md->sm, &nr_total);
1157 if (r) {
1158 DMERR("dm_pool_get_metadata_dev_size returned %d", r);
1159 return r;
1160 }
1161
1162 s->used = nr_total - nr_free;
1163 s->total = nr_total;
1164 s->snap = md->metadata_snap;
1165 s->era = md->current_era;
1166
1167 return 0;
1168}
1169
1170/*----------------------------------------------------------------*/
1171
1172struct era {
1173 struct dm_target *ti;
1174
1175 struct dm_dev *metadata_dev;
1176 struct dm_dev *origin_dev;
1177
1178 dm_block_t nr_blocks;
1179 uint32_t sectors_per_block;
1180 int sectors_per_block_shift;
1181 struct era_metadata *md;
1182
1183 struct workqueue_struct *wq;
1184 struct work_struct worker;
1185
1186 spinlock_t deferred_lock;
1187 struct bio_list deferred_bios;
1188
1189 spinlock_t rpc_lock;
1190 struct list_head rpc_calls;
1191
1192 struct digest digest;
1193 atomic_t suspended;
1194};
1195
1196struct rpc {
1197 struct list_head list;
1198
1199 int (*fn0)(struct era_metadata *md);
1200 int (*fn1)(struct era_metadata *md, void *ref);
1201 void *arg;
1202 int result;
1203
1204 struct completion complete;
1205};
1206
1207/*
1208 *---------------------------------------------------------------
1209 * Remapping.
1210 *---------------------------------------------------------------
1211 */
1212static bool block_size_is_power_of_two(struct era *era)
1213{
1214 return era->sectors_per_block_shift >= 0;
1215}
1216
1217static dm_block_t get_block(struct era *era, struct bio *bio)
1218{
1219 sector_t block_nr = bio->bi_iter.bi_sector;
1220
1221 if (!block_size_is_power_of_two(era))
1222 (void) sector_div(block_nr, era->sectors_per_block);
1223 else
1224 block_nr >>= era->sectors_per_block_shift;
1225
1226 return block_nr;
1227}
1228
1229static void remap_to_origin(struct era *era, struct bio *bio)
1230{
1231 bio_set_dev(bio, era->origin_dev->bdev);
1232}
1233
1234/*
1235 *--------------------------------------------------------------
1236 * Worker thread
1237 *--------------------------------------------------------------
1238 */
1239static void wake_worker(struct era *era)
1240{
1241 if (!atomic_read(&era->suspended))
1242 queue_work(era->wq, &era->worker);
1243}
1244
1245static void process_old_eras(struct era *era)
1246{
1247 int r;
1248
1249 if (!era->digest.step)
1250 return;
1251
1252 r = era->digest.step(era->md, &era->digest);
1253 if (r < 0) {
1254 DMERR("%s: digest step failed, stopping digestion", __func__);
1255 era->digest.step = NULL;
1256
1257 } else if (era->digest.step)
1258 wake_worker(era);
1259}
1260
1261static void process_deferred_bios(struct era *era)
1262{
1263 int r;
1264 struct bio_list deferred_bios, marked_bios;
1265 struct bio *bio;
1266 struct blk_plug plug;
1267 bool commit_needed = false;
1268 bool failed = false;
1269 struct writeset *ws = era->md->current_writeset;
1270
1271 bio_list_init(&deferred_bios);
1272 bio_list_init(&marked_bios);
1273
1274 spin_lock(&era->deferred_lock);
1275 bio_list_merge(&deferred_bios, &era->deferred_bios);
1276 bio_list_init(&era->deferred_bios);
1277 spin_unlock(&era->deferred_lock);
1278
1279 if (bio_list_empty(&deferred_bios))
1280 return;
1281
1282 while ((bio = bio_list_pop(&deferred_bios))) {
1283 r = writeset_test_and_set(&era->md->bitset_info, ws,
1284 get_block(era, bio));
1285 if (r < 0) {
1286 /*
1287 * This is bad news, we need to rollback.
1288 * FIXME: finish.
1289 */
1290 failed = true;
1291 } else if (r == 0)
1292 commit_needed = true;
1293
1294 bio_list_add(&marked_bios, bio);
1295 }
1296
1297 if (commit_needed) {
1298 r = metadata_commit(era->md);
1299 if (r)
1300 failed = true;
1301 }
1302
1303 if (failed)
1304 while ((bio = bio_list_pop(&marked_bios)))
1305 bio_io_error(bio);
1306 else {
1307 blk_start_plug(&plug);
1308 while ((bio = bio_list_pop(&marked_bios))) {
1309 /*
1310 * Only update the in-core writeset if the on-disk one
1311 * was updated too.
1312 */
1313 if (commit_needed)
1314 set_bit(get_block(era, bio), ws->bits);
1315 submit_bio_noacct(bio);
1316 }
1317 blk_finish_plug(&plug);
1318 }
1319}
1320
1321static void process_rpc_calls(struct era *era)
1322{
1323 int r;
1324 bool need_commit = false;
1325 struct list_head calls;
1326 struct rpc *rpc, *tmp;
1327
1328 INIT_LIST_HEAD(&calls);
1329 spin_lock(&era->rpc_lock);
1330 list_splice_init(&era->rpc_calls, &calls);
1331 spin_unlock(&era->rpc_lock);
1332
1333 list_for_each_entry_safe(rpc, tmp, &calls, list) {
1334 rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg);
1335 need_commit = true;
1336 }
1337
1338 if (need_commit) {
1339 r = metadata_commit(era->md);
1340 if (r)
1341 list_for_each_entry_safe(rpc, tmp, &calls, list)
1342 rpc->result = r;
1343 }
1344
1345 list_for_each_entry_safe(rpc, tmp, &calls, list)
1346 complete(&rpc->complete);
1347}
1348
1349static void kick_off_digest(struct era *era)
1350{
1351 if (era->md->archived_writesets) {
1352 era->md->archived_writesets = false;
1353 metadata_digest_start(era->md, &era->digest);
1354 }
1355}
1356
1357static void do_work(struct work_struct *ws)
1358{
1359 struct era *era = container_of(ws, struct era, worker);
1360
1361 kick_off_digest(era);
1362 process_old_eras(era);
1363 process_deferred_bios(era);
1364 process_rpc_calls(era);
1365}
1366
1367static void defer_bio(struct era *era, struct bio *bio)
1368{
1369 spin_lock(&era->deferred_lock);
1370 bio_list_add(&era->deferred_bios, bio);
1371 spin_unlock(&era->deferred_lock);
1372
1373 wake_worker(era);
1374}
1375
1376/*
1377 * Make an rpc call to the worker to change the metadata.
1378 */
1379static int perform_rpc(struct era *era, struct rpc *rpc)
1380{
1381 rpc->result = 0;
1382 init_completion(&rpc->complete);
1383
1384 spin_lock(&era->rpc_lock);
1385 list_add(&rpc->list, &era->rpc_calls);
1386 spin_unlock(&era->rpc_lock);
1387
1388 wake_worker(era);
1389 wait_for_completion(&rpc->complete);
1390
1391 return rpc->result;
1392}
1393
1394static int in_worker0(struct era *era, int (*fn)(struct era_metadata *md))
1395{
1396 struct rpc rpc;
1397
1398 rpc.fn0 = fn;
1399 rpc.fn1 = NULL;
1400
1401 return perform_rpc(era, &rpc);
1402}
1403
1404static int in_worker1(struct era *era,
1405 int (*fn)(struct era_metadata *md, void *ref), void *arg)
1406{
1407 struct rpc rpc;
1408
1409 rpc.fn0 = NULL;
1410 rpc.fn1 = fn;
1411 rpc.arg = arg;
1412
1413 return perform_rpc(era, &rpc);
1414}
1415
1416static void start_worker(struct era *era)
1417{
1418 atomic_set(&era->suspended, 0);
1419}
1420
1421static void stop_worker(struct era *era)
1422{
1423 atomic_set(&era->suspended, 1);
1424 drain_workqueue(era->wq);
1425}
1426
1427/*
1428 *--------------------------------------------------------------
1429 * Target methods
1430 *--------------------------------------------------------------
1431 */
1432static void era_destroy(struct era *era)
1433{
1434 if (era->md)
1435 metadata_close(era->md);
1436
1437 if (era->wq)
1438 destroy_workqueue(era->wq);
1439
1440 if (era->origin_dev)
1441 dm_put_device(era->ti, era->origin_dev);
1442
1443 if (era->metadata_dev)
1444 dm_put_device(era->ti, era->metadata_dev);
1445
1446 kfree(era);
1447}
1448
1449static dm_block_t calc_nr_blocks(struct era *era)
1450{
1451 return dm_sector_div_up(era->ti->len, era->sectors_per_block);
1452}
1453
1454static bool valid_block_size(dm_block_t block_size)
1455{
1456 bool greater_than_zero = block_size > 0;
1457 bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0;
1458
1459 return greater_than_zero && multiple_of_min_block_size;
1460}
1461
1462/*
1463 * <metadata dev> <data dev> <data block size (sectors)>
1464 */
1465static int era_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1466{
1467 int r;
1468 char dummy;
1469 struct era *era;
1470 struct era_metadata *md;
1471
1472 if (argc != 3) {
1473 ti->error = "Invalid argument count";
1474 return -EINVAL;
1475 }
1476
1477 era = kzalloc(sizeof(*era), GFP_KERNEL);
1478 if (!era) {
1479 ti->error = "Error allocating era structure";
1480 return -ENOMEM;
1481 }
1482
1483 era->ti = ti;
1484
1485 r = dm_get_device(ti, argv[0], BLK_OPEN_READ | BLK_OPEN_WRITE,
1486 &era->metadata_dev);
1487 if (r) {
1488 ti->error = "Error opening metadata device";
1489 era_destroy(era);
1490 return -EINVAL;
1491 }
1492
1493 r = dm_get_device(ti, argv[1], BLK_OPEN_READ | BLK_OPEN_WRITE,
1494 &era->origin_dev);
1495 if (r) {
1496 ti->error = "Error opening data device";
1497 era_destroy(era);
1498 return -EINVAL;
1499 }
1500
1501 r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy);
1502 if (r != 1) {
1503 ti->error = "Error parsing block size";
1504 era_destroy(era);
1505 return -EINVAL;
1506 }
1507
1508 r = dm_set_target_max_io_len(ti, era->sectors_per_block);
1509 if (r) {
1510 ti->error = "could not set max io len";
1511 era_destroy(era);
1512 return -EINVAL;
1513 }
1514
1515 if (!valid_block_size(era->sectors_per_block)) {
1516 ti->error = "Invalid block size";
1517 era_destroy(era);
1518 return -EINVAL;
1519 }
1520 if (era->sectors_per_block & (era->sectors_per_block - 1))
1521 era->sectors_per_block_shift = -1;
1522 else
1523 era->sectors_per_block_shift = __ffs(era->sectors_per_block);
1524
1525 md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true);
1526 if (IS_ERR(md)) {
1527 ti->error = "Error reading metadata";
1528 era_destroy(era);
1529 return PTR_ERR(md);
1530 }
1531 era->md = md;
1532
1533 era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1534 if (!era->wq) {
1535 ti->error = "could not create workqueue for metadata object";
1536 era_destroy(era);
1537 return -ENOMEM;
1538 }
1539 INIT_WORK(&era->worker, do_work);
1540
1541 spin_lock_init(&era->deferred_lock);
1542 bio_list_init(&era->deferred_bios);
1543
1544 spin_lock_init(&era->rpc_lock);
1545 INIT_LIST_HEAD(&era->rpc_calls);
1546
1547 ti->private = era;
1548 ti->num_flush_bios = 1;
1549 ti->flush_supported = true;
1550
1551 ti->num_discard_bios = 1;
1552
1553 return 0;
1554}
1555
1556static void era_dtr(struct dm_target *ti)
1557{
1558 era_destroy(ti->private);
1559}
1560
1561static int era_map(struct dm_target *ti, struct bio *bio)
1562{
1563 struct era *era = ti->private;
1564 dm_block_t block = get_block(era, bio);
1565
1566 /*
1567 * All bios get remapped to the origin device. We do this now, but
1568 * it may not get issued until later. Depending on whether the
1569 * block is marked in this era.
1570 */
1571 remap_to_origin(era, bio);
1572
1573 /*
1574 * REQ_PREFLUSH bios carry no data, so we're not interested in them.
1575 */
1576 if (!(bio->bi_opf & REQ_PREFLUSH) &&
1577 (bio_data_dir(bio) == WRITE) &&
1578 !metadata_current_marked(era->md, block)) {
1579 defer_bio(era, bio);
1580 return DM_MAPIO_SUBMITTED;
1581 }
1582
1583 return DM_MAPIO_REMAPPED;
1584}
1585
1586static void era_postsuspend(struct dm_target *ti)
1587{
1588 int r;
1589 struct era *era = ti->private;
1590
1591 r = in_worker0(era, metadata_era_archive);
1592 if (r) {
1593 DMERR("%s: couldn't archive current era", __func__);
1594 /* FIXME: fail mode */
1595 }
1596
1597 stop_worker(era);
1598
1599 r = metadata_commit(era->md);
1600 if (r) {
1601 DMERR("%s: metadata_commit failed", __func__);
1602 /* FIXME: fail mode */
1603 }
1604}
1605
1606static int era_preresume(struct dm_target *ti)
1607{
1608 int r;
1609 struct era *era = ti->private;
1610 dm_block_t new_size = calc_nr_blocks(era);
1611
1612 if (era->nr_blocks != new_size) {
1613 r = metadata_resize(era->md, &new_size);
1614 if (r) {
1615 DMERR("%s: metadata_resize failed", __func__);
1616 return r;
1617 }
1618
1619 r = metadata_commit(era->md);
1620 if (r) {
1621 DMERR("%s: metadata_commit failed", __func__);
1622 return r;
1623 }
1624
1625 era->nr_blocks = new_size;
1626 }
1627
1628 start_worker(era);
1629
1630 r = in_worker0(era, metadata_era_rollover);
1631 if (r) {
1632 DMERR("%s: metadata_era_rollover failed", __func__);
1633 return r;
1634 }
1635
1636 return 0;
1637}
1638
1639/*
1640 * Status format:
1641 *
1642 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
1643 * <current era> <held metadata root | '-'>
1644 */
1645static void era_status(struct dm_target *ti, status_type_t type,
1646 unsigned int status_flags, char *result, unsigned int maxlen)
1647{
1648 int r;
1649 struct era *era = ti->private;
1650 ssize_t sz = 0;
1651 struct metadata_stats stats;
1652 char buf[BDEVNAME_SIZE];
1653
1654 switch (type) {
1655 case STATUSTYPE_INFO:
1656 r = in_worker1(era, metadata_get_stats, &stats);
1657 if (r)
1658 goto err;
1659
1660 DMEMIT("%u %llu/%llu %u",
1661 (unsigned int) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
1662 (unsigned long long) stats.used,
1663 (unsigned long long) stats.total,
1664 (unsigned int) stats.era);
1665
1666 if (stats.snap != SUPERBLOCK_LOCATION)
1667 DMEMIT(" %llu", stats.snap);
1668 else
1669 DMEMIT(" -");
1670 break;
1671
1672 case STATUSTYPE_TABLE:
1673 format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
1674 DMEMIT("%s ", buf);
1675 format_dev_t(buf, era->origin_dev->bdev->bd_dev);
1676 DMEMIT("%s %u", buf, era->sectors_per_block);
1677 break;
1678
1679 case STATUSTYPE_IMA:
1680 *result = '\0';
1681 break;
1682 }
1683
1684 return;
1685
1686err:
1687 DMEMIT("Error");
1688}
1689
1690static int era_message(struct dm_target *ti, unsigned int argc, char **argv,
1691 char *result, unsigned int maxlen)
1692{
1693 struct era *era = ti->private;
1694
1695 if (argc != 1) {
1696 DMERR("incorrect number of message arguments");
1697 return -EINVAL;
1698 }
1699
1700 if (!strcasecmp(argv[0], "checkpoint"))
1701 return in_worker0(era, metadata_checkpoint);
1702
1703 if (!strcasecmp(argv[0], "take_metadata_snap"))
1704 return in_worker0(era, metadata_take_snap);
1705
1706 if (!strcasecmp(argv[0], "drop_metadata_snap"))
1707 return in_worker0(era, metadata_drop_snap);
1708
1709 DMERR("unsupported message '%s'", argv[0]);
1710 return -EINVAL;
1711}
1712
1713static sector_t get_dev_size(struct dm_dev *dev)
1714{
1715 return bdev_nr_sectors(dev->bdev);
1716}
1717
1718static int era_iterate_devices(struct dm_target *ti,
1719 iterate_devices_callout_fn fn, void *data)
1720{
1721 struct era *era = ti->private;
1722
1723 return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
1724}
1725
1726static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
1727{
1728 struct era *era = ti->private;
1729 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
1730
1731 /*
1732 * If the system-determined stacked limits are compatible with the
1733 * era device's blocksize (io_opt is a factor) do not override them.
1734 */
1735 if (io_opt_sectors < era->sectors_per_block ||
1736 do_div(io_opt_sectors, era->sectors_per_block)) {
1737 blk_limits_io_min(limits, 0);
1738 blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT);
1739 }
1740}
1741
1742/*----------------------------------------------------------------*/
1743
1744static struct target_type era_target = {
1745 .name = "era",
1746 .version = {1, 0, 0},
1747 .module = THIS_MODULE,
1748 .ctr = era_ctr,
1749 .dtr = era_dtr,
1750 .map = era_map,
1751 .postsuspend = era_postsuspend,
1752 .preresume = era_preresume,
1753 .status = era_status,
1754 .message = era_message,
1755 .iterate_devices = era_iterate_devices,
1756 .io_hints = era_io_hints
1757};
1758module_dm(era);
1759
1760MODULE_DESCRIPTION(DM_NAME " era target");
1761MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
1762MODULE_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 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 flush_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
1575static int era_preresume(struct dm_target *ti)
1576{
1577 int r;
1578 struct era *era = ti->private;
1579 dm_block_t new_size = calc_nr_blocks(era);
1580
1581 if (era->nr_blocks != new_size) {
1582 r = metadata_resize(era->md, &new_size);
1583 if (r) {
1584 DMERR("%s: metadata_resize failed", __func__);
1585 return r;
1586 }
1587
1588 r = metadata_commit(era->md);
1589 if (r) {
1590 DMERR("%s: metadata_commit failed", __func__);
1591 return r;
1592 }
1593
1594 era->nr_blocks = new_size;
1595 }
1596
1597 start_worker(era);
1598
1599 r = in_worker0(era, metadata_era_rollover);
1600 if (r) {
1601 DMERR("%s: metadata_era_rollover failed", __func__);
1602 return r;
1603 }
1604
1605 return 0;
1606}
1607
1608/*
1609 * Status format:
1610 *
1611 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
1612 * <current era> <held metadata root | '-'>
1613 */
1614static void era_status(struct dm_target *ti, status_type_t type,
1615 unsigned status_flags, char *result, unsigned maxlen)
1616{
1617 int r;
1618 struct era *era = ti->private;
1619 ssize_t sz = 0;
1620 struct metadata_stats stats;
1621 char buf[BDEVNAME_SIZE];
1622
1623 switch (type) {
1624 case STATUSTYPE_INFO:
1625 r = in_worker1(era, metadata_get_stats, &stats);
1626 if (r)
1627 goto err;
1628
1629 DMEMIT("%u %llu/%llu %u",
1630 (unsigned) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
1631 (unsigned long long) stats.used,
1632 (unsigned long long) stats.total,
1633 (unsigned) stats.era);
1634
1635 if (stats.snap != SUPERBLOCK_LOCATION)
1636 DMEMIT(" %llu", stats.snap);
1637 else
1638 DMEMIT(" -");
1639 break;
1640
1641 case STATUSTYPE_TABLE:
1642 format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
1643 DMEMIT("%s ", buf);
1644 format_dev_t(buf, era->origin_dev->bdev->bd_dev);
1645 DMEMIT("%s %u", buf, era->sectors_per_block);
1646 break;
1647 }
1648
1649 return;
1650
1651err:
1652 DMEMIT("Error");
1653}
1654
1655static int era_message(struct dm_target *ti, unsigned argc, char **argv,
1656 char *result, unsigned maxlen)
1657{
1658 struct era *era = ti->private;
1659
1660 if (argc != 1) {
1661 DMERR("incorrect number of message arguments");
1662 return -EINVAL;
1663 }
1664
1665 if (!strcasecmp(argv[0], "checkpoint"))
1666 return in_worker0(era, metadata_checkpoint);
1667
1668 if (!strcasecmp(argv[0], "take_metadata_snap"))
1669 return in_worker0(era, metadata_take_snap);
1670
1671 if (!strcasecmp(argv[0], "drop_metadata_snap"))
1672 return in_worker0(era, metadata_drop_snap);
1673
1674 DMERR("unsupported message '%s'", argv[0]);
1675 return -EINVAL;
1676}
1677
1678static sector_t get_dev_size(struct dm_dev *dev)
1679{
1680 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
1681}
1682
1683static int era_iterate_devices(struct dm_target *ti,
1684 iterate_devices_callout_fn fn, void *data)
1685{
1686 struct era *era = ti->private;
1687 return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
1688}
1689
1690static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
1691{
1692 struct era *era = ti->private;
1693 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
1694
1695 /*
1696 * If the system-determined stacked limits are compatible with the
1697 * era device's blocksize (io_opt is a factor) do not override them.
1698 */
1699 if (io_opt_sectors < era->sectors_per_block ||
1700 do_div(io_opt_sectors, era->sectors_per_block)) {
1701 blk_limits_io_min(limits, 0);
1702 blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT);
1703 }
1704}
1705
1706/*----------------------------------------------------------------*/
1707
1708static struct target_type era_target = {
1709 .name = "era",
1710 .version = {1, 0, 0},
1711 .module = THIS_MODULE,
1712 .ctr = era_ctr,
1713 .dtr = era_dtr,
1714 .map = era_map,
1715 .postsuspend = era_postsuspend,
1716 .preresume = era_preresume,
1717 .status = era_status,
1718 .message = era_message,
1719 .iterate_devices = era_iterate_devices,
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");