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(addr: 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, new_root: root);
61 if (r)
62 return r;
63
64 return dm_bitset_resize(info, old_root: *root, old_nr_entries: 0, new_nr_entries: nr_bits, default_value: false, new_root: 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, nr_bits: ws->md.nr_bits, root: &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, root: m->root, index: block, new_root: &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, root: ws->md.root, index: block, new_root: &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(const 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(const 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 const 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(bm: md->bm, SUPERBLOCK_LOCATION,
315 v: &sb_validator, result: 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(bm: md->bm, SUPERBLOCK_LOCATION,
322 v: &sb_validator, result: sblock);
323}
324
325static int superblock_lock(struct era_metadata *md,
326 struct dm_block **sblock)
327{
328 return dm_bm_write_lock(bm: md->bm, SUPERBLOCK_LOCATION,
329 v: &sb_validator, result: 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, result: &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(tm: 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(info: &md->bitset_info, root: b);
401 }
402}
403
404static int ws_eq(void *context, const void *value1, const void *value2)
405{
406 return !memcmp(p: value1, q: value2, size: 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(info: &md->era_array_info, tm: md->tm, vt: &vt);
435}
436
437static void setup_infos(struct era_metadata *md)
438{
439 dm_disk_bitset_init(tm: md->tm, info: &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(bm: md->bm, SUPERBLOCK_LOCATION,
451 tm: &md->tm, sm: &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(info: &md->writeset_tree_info, root: &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(info: &md->era_array_info, root: &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(sm: md->sm);
475 dm_tm_destroy(tm: 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(sm: md->sm, result: &metadata_len);
486 if (r < 0)
487 return r;
488
489 return dm_sm_copy_root(sm: md->sm, copy_to_here_le: &md->metadata_space_map_root,
490 len: 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(core: &md->current_writeset->md, disk: &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: &sblock);
540 if (r)
541 return r;
542
543 disk = dm_block_data(b: sblock);
544 prepare_superblock(md, disk);
545
546 return dm_tm_commit(tm: md->tm, superblock: 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(sm: md->sm);
563 dm_tm_destroy(tm: 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: &sblock);
577 if (r) {
578 DMERR("couldn't read_lock superblock");
579 return r;
580 }
581
582 disk = dm_block_data(b: 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(bm: md->bm, SUPERBLOCK_LOCATION,
593 sm_root: disk->metadata_space_map_root,
594 root_len: sizeof(disk->metadata_space_map_root),
595 tm: &md->tm, sm: &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: &disk->current_writeset, core: &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(b: sblock);
613
614 return 0;
615
616bad:
617 dm_bm_unlock(b: 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(bm: md->bm, result: &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(bdev: md->bdev, DM_ERA_METADATA_BLOCK_SIZE,
643 ERA_MAX_CONCURRENT_LOCKS);
644 if (IS_ERR(ptr: md->bm)) {
645 DMERR("could not create block manager");
646 return PTR_ERR(ptr: md->bm);
647 }
648
649 r = open_or_format_metadata(md, may_format);
650 if (r)
651 dm_block_manager_destroy(bm: md->bm);
652
653 return r;
654}
655
656static void destroy_persistent_data_objects(struct era_metadata *md)
657{
658 dm_sm_destroy(sm: md->sm);
659 dm_tm_destroy(tm: md->tm);
660 dm_block_manager_destroy(bm: 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(info: &md->writeset_tree_info, root: md->writeset_tree_root,
701 keys: &key, new_root: &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(info: &d->info, m: &d->writeset, block: b, result: &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(info: &md->era_array_info, root: md->era_array_root,
732 index: b, value: &d->value, new_root: &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(info: &md->writeset_tree_info,
755 root: md->writeset_tree_root, result_keys: &key);
756 if (r < 0)
757 return r;
758
759 d->era = key;
760
761 r = dm_btree_lookup(info: &md->writeset_tree_info,
762 root: md->writeset_tree_root, keys: &key, value_le: &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: &disk, core: &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(tm: md->tm, info: &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(objp: md);
826 return ERR_PTR(error: r);
827 }
828
829 return md;
830}
831
832static void metadata_close(struct era_metadata *md)
833{
834 writeset_free(ws: &md->writesets[0]);
835 writeset_free(ws: &md->writesets[1]);
836 destroy_persistent_data_objects(md);
837 kfree(objp: 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(n: *new_size)) {
856 DMERR("Invalid number of origin blocks %llu",
857 (unsigned long long) *new_size);
858 return -EINVAL;
859 }
860
861 writeset_free(ws: &md->writesets[0]);
862 writeset_free(ws: &md->writesets[1]);
863
864 r = writeset_alloc(ws: &md->writesets[0], nr_blocks: *new_size);
865 if (r) {
866 DMERR("%s: writeset_alloc failed for writeset 0", __func__);
867 return r;
868 }
869
870 r = writeset_alloc(ws: &md->writesets[1], nr_blocks: *new_size);
871 if (r) {
872 DMERR("%s: writeset_alloc failed for writeset 1", __func__);
873 writeset_free(ws: &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(info: &md->era_array_info, root: md->era_array_root,
880 old_size: md->nr_blocks, new_size: *new_size,
881 value: &value, new_root: &md->era_array_root);
882 if (r) {
883 DMERR("%s: dm_array_resize failed", __func__);
884 writeset_free(ws: &md->writesets[0]);
885 writeset_free(ws: &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(info: &md->bitset_info, root: md->current_writeset->md.root,
900 new_root: &md->current_writeset->md.root);
901 if (r) {
902 DMERR("%s: dm_bitset_flush failed", __func__);
903 return r;
904 }
905
906 ws_pack(core: &md->current_writeset->md, disk: &value);
907
908 keys[0] = md->current_era;
909 __dm_bless_for_disk(&value);
910 r = dm_btree_insert(info: &md->writeset_tree_info, root: md->writeset_tree_root,
911 keys, value: &value, new_root: &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(info: &md->bitset_info, ws: new_writeset, nr_blocks: 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(info: &md->bitset_info, root: md->current_writeset->md.root,
990 new_root: &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(tm: 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: &sblock);
1010 if (r) {
1011 DMERR("%s: superblock lock failed", __func__);
1012 return r;
1013 }
1014
1015 prepare_superblock(md, disk: dm_block_data(b: sblock));
1016
1017 return dm_tm_commit(tm: md->tm, superblock: 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(sm: 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(tm: md->tm, SUPERBLOCK_LOCATION,
1061 v: &sb_validator, result: &clone, inc_children: &inc);
1062 if (r) {
1063 DMERR("%s: couldn't shadow superblock", __func__);
1064 dm_sm_dec_block(sm: md->sm, SUPERBLOCK_LOCATION);
1065 return r;
1066 }
1067 BUG_ON(!inc);
1068
1069 r = dm_sm_inc_block(sm: md->sm, b: md->writeset_tree_root);
1070 if (r) {
1071 DMERR("%s: couldn't inc writeset tree root", __func__);
1072 dm_tm_unlock(tm: md->tm, b: clone);
1073 return r;
1074 }
1075
1076 r = dm_sm_inc_block(sm: md->sm, b: md->era_array_root);
1077 if (r) {
1078 DMERR("%s: couldn't inc era tree root", __func__);
1079 dm_sm_dec_block(sm: md->sm, b: md->writeset_tree_root);
1080 dm_tm_unlock(tm: md->tm, b: clone);
1081 return r;
1082 }
1083
1084 md->metadata_snap = dm_block_location(b: clone);
1085
1086 dm_tm_unlock(tm: md->tm, b: 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(tm: md->tm, b: md->metadata_snap, v: &sb_validator, result: &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(b: clone);
1116 r = dm_btree_del(info: &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(tm: md->tm, b: clone);
1121 return r;
1122 }
1123
1124 r = dm_array_del(info: &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(tm: md->tm, b: clone);
1128 return r;
1129 }
1130
1131 location = dm_block_location(b: clone);
1132 dm_tm_unlock(tm: md->tm, b: clone);
1133
1134 return dm_sm_dec_block(sm: md->sm, b: 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(sm: md->sm, count: &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(sm: md->sm, count: &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, bdev: 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(v: &era->suspended))
1242 queue_work(wq: era->wq, work: &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(bl: &deferred_bios);
1272 bio_list_init(bl: &marked_bios);
1273
1274 spin_lock(lock: &era->deferred_lock);
1275 bio_list_merge_init(bl: &deferred_bios, bl2: &era->deferred_bios);
1276 spin_unlock(lock: &era->deferred_lock);
1277
1278 if (bio_list_empty(bl: &deferred_bios))
1279 return;
1280
1281 while ((bio = bio_list_pop(bl: &deferred_bios))) {
1282 r = writeset_test_and_set(info: &era->md->bitset_info, ws,
1283 block: get_block(era, bio));
1284 if (r < 0) {
1285 /*
1286 * This is bad news, we need to rollback.
1287 * FIXME: finish.
1288 */
1289 failed = true;
1290 } else if (r == 0)
1291 commit_needed = true;
1292
1293 bio_list_add(bl: &marked_bios, bio);
1294 }
1295
1296 if (commit_needed) {
1297 r = metadata_commit(md: era->md);
1298 if (r)
1299 failed = true;
1300 }
1301
1302 if (failed)
1303 while ((bio = bio_list_pop(bl: &marked_bios)))
1304 bio_io_error(bio);
1305 else {
1306 blk_start_plug(&plug);
1307 while ((bio = bio_list_pop(bl: &marked_bios))) {
1308 /*
1309 * Only update the in-core writeset if the on-disk one
1310 * was updated too.
1311 */
1312 if (commit_needed)
1313 set_bit(nr: get_block(era, bio), addr: ws->bits);
1314 submit_bio_noacct(bio);
1315 }
1316 blk_finish_plug(&plug);
1317 }
1318}
1319
1320static void process_rpc_calls(struct era *era)
1321{
1322 int r;
1323 bool need_commit = false;
1324 struct list_head calls;
1325 struct rpc *rpc, *tmp;
1326
1327 INIT_LIST_HEAD(list: &calls);
1328 spin_lock(lock: &era->rpc_lock);
1329 list_splice_init(list: &era->rpc_calls, head: &calls);
1330 spin_unlock(lock: &era->rpc_lock);
1331
1332 list_for_each_entry_safe(rpc, tmp, &calls, list) {
1333 rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg);
1334 need_commit = true;
1335 }
1336
1337 if (need_commit) {
1338 r = metadata_commit(md: era->md);
1339 if (r)
1340 list_for_each_entry_safe(rpc, tmp, &calls, list)
1341 rpc->result = r;
1342 }
1343
1344 list_for_each_entry_safe(rpc, tmp, &calls, list)
1345 complete(&rpc->complete);
1346}
1347
1348static void kick_off_digest(struct era *era)
1349{
1350 if (era->md->archived_writesets) {
1351 era->md->archived_writesets = false;
1352 metadata_digest_start(md: era->md, d: &era->digest);
1353 }
1354}
1355
1356static void do_work(struct work_struct *ws)
1357{
1358 struct era *era = container_of(ws, struct era, worker);
1359
1360 kick_off_digest(era);
1361 process_old_eras(era);
1362 process_deferred_bios(era);
1363 process_rpc_calls(era);
1364}
1365
1366static void defer_bio(struct era *era, struct bio *bio)
1367{
1368 spin_lock(lock: &era->deferred_lock);
1369 bio_list_add(bl: &era->deferred_bios, bio);
1370 spin_unlock(lock: &era->deferred_lock);
1371
1372 wake_worker(era);
1373}
1374
1375/*
1376 * Make an rpc call to the worker to change the metadata.
1377 */
1378static int perform_rpc(struct era *era, struct rpc *rpc)
1379{
1380 rpc->result = 0;
1381 init_completion(x: &rpc->complete);
1382
1383 spin_lock(lock: &era->rpc_lock);
1384 list_add(new: &rpc->list, head: &era->rpc_calls);
1385 spin_unlock(lock: &era->rpc_lock);
1386
1387 wake_worker(era);
1388 wait_for_completion(&rpc->complete);
1389
1390 return rpc->result;
1391}
1392
1393static int in_worker0(struct era *era, int (*fn)(struct era_metadata *md))
1394{
1395 struct rpc rpc;
1396
1397 rpc.fn0 = fn;
1398 rpc.fn1 = NULL;
1399
1400 return perform_rpc(era, rpc: &rpc);
1401}
1402
1403static int in_worker1(struct era *era,
1404 int (*fn)(struct era_metadata *md, void *ref), void *arg)
1405{
1406 struct rpc rpc;
1407
1408 rpc.fn0 = NULL;
1409 rpc.fn1 = fn;
1410 rpc.arg = arg;
1411
1412 return perform_rpc(era, rpc: &rpc);
1413}
1414
1415static void start_worker(struct era *era)
1416{
1417 atomic_set(v: &era->suspended, i: 0);
1418}
1419
1420static void stop_worker(struct era *era)
1421{
1422 atomic_set(v: &era->suspended, i: 1);
1423 drain_workqueue(wq: era->wq);
1424}
1425
1426/*
1427 *--------------------------------------------------------------
1428 * Target methods
1429 *--------------------------------------------------------------
1430 */
1431static void era_destroy(struct era *era)
1432{
1433 if (era->md)
1434 metadata_close(md: era->md);
1435
1436 if (era->wq)
1437 destroy_workqueue(wq: era->wq);
1438
1439 if (era->origin_dev)
1440 dm_put_device(ti: era->ti, d: era->origin_dev);
1441
1442 if (era->metadata_dev)
1443 dm_put_device(ti: era->ti, d: era->metadata_dev);
1444
1445 kfree(objp: era);
1446}
1447
1448static dm_block_t calc_nr_blocks(struct era *era)
1449{
1450 return dm_sector_div_up(era->ti->len, era->sectors_per_block);
1451}
1452
1453static bool valid_block_size(dm_block_t block_size)
1454{
1455 bool greater_than_zero = block_size > 0;
1456 bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0;
1457
1458 return greater_than_zero && multiple_of_min_block_size;
1459}
1460
1461/*
1462 * <metadata dev> <data dev> <data block size (sectors)>
1463 */
1464static int era_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1465{
1466 int r;
1467 char dummy;
1468 struct era *era;
1469 struct era_metadata *md;
1470
1471 if (argc != 3) {
1472 ti->error = "Invalid argument count";
1473 return -EINVAL;
1474 }
1475
1476 era = kzalloc(sizeof(*era), GFP_KERNEL);
1477 if (!era) {
1478 ti->error = "Error allocating era structure";
1479 return -ENOMEM;
1480 }
1481
1482 era->ti = ti;
1483
1484 r = dm_get_device(ti, path: argv[0], BLK_OPEN_READ | BLK_OPEN_WRITE,
1485 result: &era->metadata_dev);
1486 if (r) {
1487 ti->error = "Error opening metadata device";
1488 era_destroy(era);
1489 return -EINVAL;
1490 }
1491
1492 r = dm_get_device(ti, path: argv[1], BLK_OPEN_READ | BLK_OPEN_WRITE,
1493 result: &era->origin_dev);
1494 if (r) {
1495 ti->error = "Error opening data device";
1496 era_destroy(era);
1497 return -EINVAL;
1498 }
1499
1500 r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy);
1501 if (r != 1) {
1502 ti->error = "Error parsing block size";
1503 era_destroy(era);
1504 return -EINVAL;
1505 }
1506
1507 r = dm_set_target_max_io_len(ti, len: era->sectors_per_block);
1508 if (r) {
1509 ti->error = "could not set max io len";
1510 era_destroy(era);
1511 return -EINVAL;
1512 }
1513
1514 if (!valid_block_size(block_size: era->sectors_per_block)) {
1515 ti->error = "Invalid block size";
1516 era_destroy(era);
1517 return -EINVAL;
1518 }
1519 if (era->sectors_per_block & (era->sectors_per_block - 1))
1520 era->sectors_per_block_shift = -1;
1521 else
1522 era->sectors_per_block_shift = __ffs(era->sectors_per_block);
1523
1524 md = metadata_open(bdev: era->metadata_dev->bdev, block_size: era->sectors_per_block, may_format: true);
1525 if (IS_ERR(ptr: md)) {
1526 ti->error = "Error reading metadata";
1527 era_destroy(era);
1528 return PTR_ERR(ptr: md);
1529 }
1530 era->md = md;
1531
1532 era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
1533 if (!era->wq) {
1534 ti->error = "could not create workqueue for metadata object";
1535 era_destroy(era);
1536 return -ENOMEM;
1537 }
1538 INIT_WORK(&era->worker, do_work);
1539
1540 spin_lock_init(&era->deferred_lock);
1541 bio_list_init(bl: &era->deferred_bios);
1542
1543 spin_lock_init(&era->rpc_lock);
1544 INIT_LIST_HEAD(list: &era->rpc_calls);
1545
1546 ti->private = era;
1547 ti->num_flush_bios = 1;
1548 ti->flush_supported = true;
1549
1550 ti->num_discard_bios = 1;
1551
1552 return 0;
1553}
1554
1555static void era_dtr(struct dm_target *ti)
1556{
1557 era_destroy(era: ti->private);
1558}
1559
1560static int era_map(struct dm_target *ti, struct bio *bio)
1561{
1562 struct era *era = ti->private;
1563 dm_block_t block = get_block(era, bio);
1564
1565 /*
1566 * All bios get remapped to the origin device. We do this now, but
1567 * it may not get issued until later. Depending on whether the
1568 * block is marked in this era.
1569 */
1570 remap_to_origin(era, bio);
1571
1572 /*
1573 * REQ_PREFLUSH bios carry no data, so we're not interested in them.
1574 */
1575 if (!(bio->bi_opf & REQ_PREFLUSH) &&
1576 (bio_data_dir(bio) == WRITE) &&
1577 !metadata_current_marked(md: era->md, block)) {
1578 defer_bio(era, bio);
1579 return DM_MAPIO_SUBMITTED;
1580 }
1581
1582 return DM_MAPIO_REMAPPED;
1583}
1584
1585static void era_postsuspend(struct dm_target *ti)
1586{
1587 int r;
1588 struct era *era = ti->private;
1589
1590 r = in_worker0(era, fn: metadata_era_archive);
1591 if (r) {
1592 DMERR("%s: couldn't archive current era", __func__);
1593 /* FIXME: fail mode */
1594 }
1595
1596 stop_worker(era);
1597
1598 r = metadata_commit(md: era->md);
1599 if (r) {
1600 DMERR("%s: metadata_commit failed", __func__);
1601 /* FIXME: fail mode */
1602 }
1603}
1604
1605static int era_preresume(struct dm_target *ti)
1606{
1607 int r;
1608 struct era *era = ti->private;
1609 dm_block_t new_size = calc_nr_blocks(era);
1610
1611 if (era->nr_blocks != new_size) {
1612 r = metadata_resize(md: era->md, arg: &new_size);
1613 if (r) {
1614 DMERR("%s: metadata_resize failed", __func__);
1615 return r;
1616 }
1617
1618 r = metadata_commit(md: era->md);
1619 if (r) {
1620 DMERR("%s: metadata_commit failed", __func__);
1621 return r;
1622 }
1623
1624 era->nr_blocks = new_size;
1625 }
1626
1627 start_worker(era);
1628
1629 r = in_worker0(era, fn: metadata_era_rollover);
1630 if (r) {
1631 DMERR("%s: metadata_era_rollover failed", __func__);
1632 return r;
1633 }
1634
1635 return 0;
1636}
1637
1638/*
1639 * Status format:
1640 *
1641 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
1642 * <current era> <held metadata root | '-'>
1643 */
1644static void era_status(struct dm_target *ti, status_type_t type,
1645 unsigned int status_flags, char *result, unsigned int maxlen)
1646{
1647 int r;
1648 struct era *era = ti->private;
1649 ssize_t sz = 0;
1650 struct metadata_stats stats;
1651 char buf[BDEVNAME_SIZE];
1652
1653 switch (type) {
1654 case STATUSTYPE_INFO:
1655 r = in_worker1(era, fn: metadata_get_stats, arg: &stats);
1656 if (r)
1657 goto err;
1658
1659 DMEMIT("%u %llu/%llu %u",
1660 (unsigned int) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
1661 (unsigned long long) stats.used,
1662 (unsigned long long) stats.total,
1663 (unsigned int) stats.era);
1664
1665 if (stats.snap != SUPERBLOCK_LOCATION)
1666 DMEMIT(" %llu", stats.snap);
1667 else
1668 DMEMIT(" -");
1669 break;
1670
1671 case STATUSTYPE_TABLE:
1672 format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
1673 DMEMIT("%s ", buf);
1674 format_dev_t(buf, era->origin_dev->bdev->bd_dev);
1675 DMEMIT("%s %u", buf, era->sectors_per_block);
1676 break;
1677
1678 case STATUSTYPE_IMA:
1679 *result = '\0';
1680 break;
1681 }
1682
1683 return;
1684
1685err:
1686 DMEMIT("Error");
1687}
1688
1689static int era_message(struct dm_target *ti, unsigned int argc, char **argv,
1690 char *result, unsigned int maxlen)
1691{
1692 struct era *era = ti->private;
1693
1694 if (argc != 1) {
1695 DMERR("incorrect number of message arguments");
1696 return -EINVAL;
1697 }
1698
1699 if (!strcasecmp(s1: argv[0], s2: "checkpoint"))
1700 return in_worker0(era, fn: metadata_checkpoint);
1701
1702 if (!strcasecmp(s1: argv[0], s2: "take_metadata_snap"))
1703 return in_worker0(era, fn: metadata_take_snap);
1704
1705 if (!strcasecmp(s1: argv[0], s2: "drop_metadata_snap"))
1706 return in_worker0(era, fn: metadata_drop_snap);
1707
1708 DMERR("unsupported message '%s'", argv[0]);
1709 return -EINVAL;
1710}
1711
1712static sector_t get_dev_size(struct dm_dev *dev)
1713{
1714 return bdev_nr_sectors(bdev: dev->bdev);
1715}
1716
1717static int era_iterate_devices(struct dm_target *ti,
1718 iterate_devices_callout_fn fn, void *data)
1719{
1720 struct era *era = ti->private;
1721
1722 return fn(ti, era->origin_dev, 0, get_dev_size(dev: era->origin_dev), data);
1723}
1724
1725static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
1726{
1727 struct era *era = ti->private;
1728 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
1729
1730 /*
1731 * If the system-determined stacked limits are compatible with the
1732 * era device's blocksize (io_opt is a factor) do not override them.
1733 */
1734 if (io_opt_sectors < era->sectors_per_block ||
1735 do_div(io_opt_sectors, era->sectors_per_block)) {
1736 limits->io_min = 0;
1737 limits->io_opt = era->sectors_per_block << SECTOR_SHIFT;
1738 }
1739}
1740
1741/*----------------------------------------------------------------*/
1742
1743static struct target_type era_target = {
1744 .name = "era",
1745 .version = {1, 0, 0},
1746 .module = THIS_MODULE,
1747 .ctr = era_ctr,
1748 .dtr = era_dtr,
1749 .map = era_map,
1750 .postsuspend = era_postsuspend,
1751 .preresume = era_preresume,
1752 .status = era_status,
1753 .message = era_message,
1754 .iterate_devices = era_iterate_devices,
1755 .io_hints = era_io_hints
1756};
1757module_dm(era);
1758
1759MODULE_DESCRIPTION(DM_NAME " era target");
1760MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
1761MODULE_LICENSE("GPL");
1762

source code of linux/drivers/md/dm-era-target.c