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dm cache: fix race in writethrough implementation
[linux-block.git] / drivers / md / dm-cache-metadata.c
CommitLineData
c6b4fcba
JT		 1/*
2 * Copyright (C) 2012 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-cache-metadata.h"
8
9#include "persistent-data/dm-array.h"
10#include "persistent-data/dm-bitset.h"
11#include "persistent-data/dm-space-map.h"
12#include "persistent-data/dm-space-map-disk.h"
13#include "persistent-data/dm-transaction-manager.h"
14
15#include <linux/device-mapper.h>
16
17/*----------------------------------------------------------------*/
18
19#define DM_MSG_PREFIX "cache metadata"
20
21#define CACHE_SUPERBLOCK_MAGIC 06142003
22#define CACHE_SUPERBLOCK_LOCATION 0
23#define CACHE_VERSION 1
24#define CACHE_METADATA_CACHE_SIZE 64
25
26/*
27 * 3 for btree insert +
28 * 2 for btree lookup used within space map
29 */
30#define CACHE_MAX_CONCURRENT_LOCKS 5
31#define SPACE_MAP_ROOT_SIZE 128
32
33enum superblock_flag_bits {
34 /* for spotting crashes that would invalidate the dirty bitset */
35 CLEAN_SHUTDOWN,
36};
37
38/*
39 * Each mapping from cache block -> origin block carries a set of flags.
40 */
41enum mapping_bits {
42 /*
43 * A valid mapping. Because we're using an array we clear this
44 * flag for an non existant mapping.
45 */
46 M_VALID = 1,
47
48 /*
49 * The data on the cache is different from that on the origin.
50 */
51 M_DIRTY = 2
52};
53
54struct cache_disk_superblock {
55 __le32 csum;
56 __le32 flags;
57 __le64 blocknr;
58
59 __u8 uuid[16];
60 __le64 magic;
61 __le32 version;
62
63 __u8 policy_name[CACHE_POLICY_NAME_SIZE];
64 __le32 policy_hint_size;
65
66 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
67 __le64 mapping_root;
68 __le64 hint_root;
69
70 __le64 discard_root;
71 __le64 discard_block_size;
72 __le64 discard_nr_blocks;
73
74 __le32 data_block_size;
75 __le32 metadata_block_size;
76 __le32 cache_blocks;
77
78 __le32 compat_flags;
79 __le32 compat_ro_flags;
80 __le32 incompat_flags;
81
82 __le32 read_hits;
83 __le32 read_misses;
84 __le32 write_hits;
85 __le32 write_misses;
86} __packed;
87
88struct dm_cache_metadata {
89 struct block_device *bdev;
90 struct dm_block_manager *bm;
91 struct dm_space_map *metadata_sm;
92 struct dm_transaction_manager *tm;
93
94 struct dm_array_info info;
95 struct dm_array_info hint_info;
96 struct dm_disk_bitset discard_info;
97
98 struct rw_semaphore root_lock;
99 dm_block_t root;
100 dm_block_t hint_root;
101 dm_block_t discard_root;
102
103 sector_t discard_block_size;
104 dm_dblock_t discard_nr_blocks;
105
106 sector_t data_block_size;
107 dm_cblock_t cache_blocks;
108 bool changed:1;
109 bool clean_when_opened:1;
110
111 char policy_name[CACHE_POLICY_NAME_SIZE];
112 size_t policy_hint_size;
113 struct dm_cache_statistics stats;
114};
115
116/*-------------------------------------------------------------------
117 * superblock validator
118 *-----------------------------------------------------------------*/
119
120#define SUPERBLOCK_CSUM_XOR 9031977
121
122static void sb_prepare_for_write(struct dm_block_validator *v,
123 struct dm_block *b,
124 size_t sb_block_size)
125{
126 struct cache_disk_superblock *disk_super = dm_block_data(b);
127
128 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
129 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
130 sb_block_size - sizeof(__le32),
131 SUPERBLOCK_CSUM_XOR));
132}
133
134static int sb_check(struct dm_block_validator *v,
135 struct dm_block *b,
136 size_t sb_block_size)
137{
138 struct cache_disk_superblock *disk_super = dm_block_data(b);
139 __le32 csum_le;
140
141 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
142 DMERR("sb_check failed: blocknr %llu: wanted %llu",
143 le64_to_cpu(disk_super->blocknr),
144 (unsigned long long)dm_block_location(b));
145 return -ENOTBLK;
146 }
147
148 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
149 DMERR("sb_check failed: magic %llu: wanted %llu",
150 le64_to_cpu(disk_super->magic),
151 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
152 return -EILSEQ;
153 }
154
155 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
156 sb_block_size - sizeof(__le32),
157 SUPERBLOCK_CSUM_XOR));
158 if (csum_le != disk_super->csum) {
159 DMERR("sb_check failed: csum %u: wanted %u",
160 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
161 return -EILSEQ;
162 }
163
164 return 0;
165}
166
167static struct dm_block_validator sb_validator = {
168 .name = "superblock",
169 .prepare_for_write = sb_prepare_for_write,
170 .check = sb_check
171};
172
173/*----------------------------------------------------------------*/
174
175static int superblock_read_lock(struct dm_cache_metadata *cmd,
176 struct dm_block **sblock)
177{
178 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
179 &sb_validator, sblock);
180}
181
182static int superblock_lock_zero(struct dm_cache_metadata *cmd,
183 struct dm_block **sblock)
184{
185 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
186 &sb_validator, sblock);
187}
188
189static int superblock_lock(struct dm_cache_metadata *cmd,
190 struct dm_block **sblock)
191{
192 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
193 &sb_validator, sblock);
194}
195
196/*----------------------------------------------------------------*/
197
198static int __superblock_all_zeroes(struct dm_block_manager *bm, int *result)
199{
200 int r;
201 unsigned i;
202 struct dm_block *b;
203 __le64 *data_le, zero = cpu_to_le64(0);
204 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
205
206 /*
207 * We can't use a validator here - it may be all zeroes.
208 */
209 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
210 if (r)
211 return r;
212
213 data_le = dm_block_data(b);
214 *result = 1;
215 for (i = 0; i < sb_block_size; i++) {
216 if (data_le[i] != zero) {
217 *result = 0;
218 break;
219 }
220 }
221
222 return dm_bm_unlock(b);
223}
224
225static void __setup_mapping_info(struct dm_cache_metadata *cmd)
226{
227 struct dm_btree_value_type vt;
228
229 vt.context = NULL;
230 vt.size = sizeof(__le64);
231 vt.inc = NULL;
232 vt.dec = NULL;
233 vt.equal = NULL;
234 dm_array_info_init(&cmd->info, cmd->tm, &vt);
235
236 if (cmd->policy_hint_size) {
237 vt.size = sizeof(__le32);
238 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
239 }
240}
241
242static int __write_initial_superblock(struct dm_cache_metadata *cmd)
243{
244 int r;
245 struct dm_block *sblock;
246 size_t metadata_len;
247 struct cache_disk_superblock *disk_super;
248 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
249
250 /* FIXME: see if we can lose the max sectors limit */
251 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
252 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
253
254 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
255 if (r < 0)
256 return r;
257
258 r = dm_tm_pre_commit(cmd->tm);
259 if (r < 0)
260 return r;
261
262 r = superblock_lock_zero(cmd, &sblock);
263 if (r)
264 return r;
265
266 disk_super = dm_block_data(sblock);
267 disk_super->flags = 0;
268 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
269 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
270 disk_super->version = cpu_to_le32(CACHE_VERSION);
271 memset(disk_super->policy_name, 0, CACHE_POLICY_NAME_SIZE);
272 disk_super->policy_hint_size = 0;
273
274 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
275 metadata_len);
276 if (r < 0)
277 goto bad_locked;
278
279 disk_super->mapping_root = cpu_to_le64(cmd->root);
280 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
281 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
282 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
283 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
284 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
285 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
286 disk_super->cache_blocks = cpu_to_le32(0);
287 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
288
289 disk_super->read_hits = cpu_to_le32(0);
290 disk_super->read_misses = cpu_to_le32(0);
291 disk_super->write_hits = cpu_to_le32(0);
292 disk_super->write_misses = cpu_to_le32(0);
293
294 return dm_tm_commit(cmd->tm, sblock);
295
296bad_locked:
297 dm_bm_unlock(sblock);
298 return r;
299}
300
301static int __format_metadata(struct dm_cache_metadata *cmd)
302{
303 int r;
304
305 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
306 &cmd->tm, &cmd->metadata_sm);
307 if (r < 0) {
308 DMERR("tm_create_with_sm failed");
309 return r;
310 }
311
312 __setup_mapping_info(cmd);
313
314 r = dm_array_empty(&cmd->info, &cmd->root);
315 if (r < 0)
316 goto bad;
317
318 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
319
320 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
321 if (r < 0)
322 goto bad;
323
324 cmd->discard_block_size = 0;
325 cmd->discard_nr_blocks = 0;
326
327 r = __write_initial_superblock(cmd);
328 if (r)
329 goto bad;
330
331 cmd->clean_when_opened = true;
332 return 0;
333
334bad:
335 dm_tm_destroy(cmd->tm);
336 dm_sm_destroy(cmd->metadata_sm);
337
338 return r;
339}
340
341static int __check_incompat_features(struct cache_disk_superblock *disk_super,
342 struct dm_cache_metadata *cmd)
343{
344 uint32_t features;
345
346 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
347 if (features) {
348 DMERR("could not access metadata due to unsupported optional features (%lx).",
349 (unsigned long)features);
350 return -EINVAL;
351 }
352
353 /*
354 * Check for read-only metadata to skip the following RDWR checks.
355 */
356 if (get_disk_ro(cmd->bdev->bd_disk))
357 return 0;
358
359 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
360 if (features) {
361 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
362 (unsigned long)features);
363 return -EINVAL;
364 }
365
366 return 0;
367}
368
369static int __open_metadata(struct dm_cache_metadata *cmd)
370{
371 int r;
372 struct dm_block *sblock;
373 struct cache_disk_superblock *disk_super;
374 unsigned long sb_flags;
375
376 r = superblock_read_lock(cmd, &sblock);
377 if (r < 0) {
378 DMERR("couldn't read lock superblock");
379 return r;
380 }
381
382 disk_super = dm_block_data(sblock);
383
384 r = __check_incompat_features(disk_super, cmd);
385 if (r < 0)
386 goto bad;
387
388 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
389 disk_super->metadata_space_map_root,
390 sizeof(disk_super->metadata_space_map_root),
391 &cmd->tm, &cmd->metadata_sm);
392 if (r < 0) {
393 DMERR("tm_open_with_sm failed");
394 goto bad;
395 }
396
397 __setup_mapping_info(cmd);
398 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
399 sb_flags = le32_to_cpu(disk_super->flags);
400 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
401 return dm_bm_unlock(sblock);
402
403bad:
404 dm_bm_unlock(sblock);
405 return r;
406}
407
408static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
409 bool format_device)
410{
411 int r, unformatted;
412
413 r = __superblock_all_zeroes(cmd->bm, &unformatted);
414 if (r)
415 return r;
416
417 if (unformatted)
418 return format_device ? __format_metadata(cmd) : -EPERM;
419
420 return __open_metadata(cmd);
421}
422
423static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
424 bool may_format_device)
425{
426 int r;
427 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE,
428 CACHE_METADATA_CACHE_SIZE,
429 CACHE_MAX_CONCURRENT_LOCKS);
430 if (IS_ERR(cmd->bm)) {
431 DMERR("could not create block manager");
432 return PTR_ERR(cmd->bm);
433 }
434
435 r = __open_or_format_metadata(cmd, may_format_device);
436 if (r)
437 dm_block_manager_destroy(cmd->bm);
438
439 return r;
440}
441
442static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
443{
444 dm_sm_destroy(cmd->metadata_sm);
445 dm_tm_destroy(cmd->tm);
446 dm_block_manager_destroy(cmd->bm);
447}
448
449typedef unsigned long (*flags_mutator)(unsigned long);
450
451static void update_flags(struct cache_disk_superblock *disk_super,
452 flags_mutator mutator)
453{
454 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
455 disk_super->flags = cpu_to_le32(sb_flags);
456}
457
458static unsigned long set_clean_shutdown(unsigned long flags)
459{
460 set_bit(CLEAN_SHUTDOWN, &flags);
461 return flags;
462}
463
464static unsigned long clear_clean_shutdown(unsigned long flags)
465{
466 clear_bit(CLEAN_SHUTDOWN, &flags);
467 return flags;
468}
469
470static void read_superblock_fields(struct dm_cache_metadata *cmd,
471 struct cache_disk_superblock *disk_super)
472{
473 cmd->root = le64_to_cpu(disk_super->mapping_root);
474 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
475 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
476 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
477 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
478 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
479 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
480 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
481 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
482
483 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
484 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
485 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
486 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
487
488 cmd->changed = false;
489}
490
491/*
492 * The mutator updates the superblock flags.
493 */
494static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
495 flags_mutator mutator)
496{
497 int r;
498 struct cache_disk_superblock *disk_super;
499 struct dm_block *sblock;
500
501 r = superblock_lock(cmd, &sblock);
502 if (r)
503 return r;
504
505 disk_super = dm_block_data(sblock);
506 update_flags(disk_super, mutator);
507 read_superblock_fields(cmd, disk_super);
508
509 return dm_bm_flush_and_unlock(cmd->bm, sblock);
510}
511
512static int __begin_transaction(struct dm_cache_metadata *cmd)
513{
514 int r;
515 struct cache_disk_superblock *disk_super;
516 struct dm_block *sblock;
517
518 /*
519 * We re-read the superblock every time. Shouldn't need to do this
520 * really.
521 */
522 r = superblock_read_lock(cmd, &sblock);
523 if (r)
524 return r;
525
526 disk_super = dm_block_data(sblock);
527 read_superblock_fields(cmd, disk_super);
528 dm_bm_unlock(sblock);
529
530 return 0;
531}
532
533static int __commit_transaction(struct dm_cache_metadata *cmd,
534 flags_mutator mutator)
535{
536 int r;
537 size_t metadata_len;
538 struct cache_disk_superblock *disk_super;
539 struct dm_block *sblock;
540
541 /*
542 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
543 */
544 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
545
546 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
547 &cmd->discard_root);
548 if (r)
549 return r;
550
551 r = dm_tm_pre_commit(cmd->tm);
552 if (r < 0)
553 return r;
554
555 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
556 if (r < 0)
557 return r;
558
559 r = superblock_lock(cmd, &sblock);
560 if (r)
561 return r;
562
563 disk_super = dm_block_data(sblock);
564
565 if (mutator)
566 update_flags(disk_super, mutator);
567
568 disk_super->mapping_root = cpu_to_le64(cmd->root);
569 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
570 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
571 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
572 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
573 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
574 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
575
576 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
577 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
578 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
579 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
580
581 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
582 metadata_len);
583 if (r < 0) {
584 dm_bm_unlock(sblock);
585 return r;
586 }
587
588 return dm_tm_commit(cmd->tm, sblock);
589}
590
591/*----------------------------------------------------------------*/
592
593/*
594 * The mappings are held in a dm-array that has 64-bit values stored in
595 * little-endian format. The index is the cblock, the high 48bits of the
596 * value are the oblock and the low 16 bit the flags.
597 */
598#define FLAGS_MASK ((1 << 16) - 1)
599
600static __le64 pack_value(dm_oblock_t block, unsigned flags)
601{
602 uint64_t value = from_oblock(block);
603 value <<= 16;
604 value = value | (flags & FLAGS_MASK);
605 return cpu_to_le64(value);
606}
607
608static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
609{
610 uint64_t value = le64_to_cpu(value_le);
611 uint64_t b = value >> 16;
612 *block = to_oblock(b);
613 *flags = value & FLAGS_MASK;
614}
615
616/*----------------------------------------------------------------*/
617
618struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
619 sector_t data_block_size,
620 bool may_format_device,
621 size_t policy_hint_size)
622{
623 int r;
624 struct dm_cache_metadata *cmd;
625
626 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
627 if (!cmd) {
628 DMERR("could not allocate metadata struct");
629 return NULL;
630 }
631
632 init_rwsem(&cmd->root_lock);
633 cmd->bdev = bdev;
634 cmd->data_block_size = data_block_size;
635 cmd->cache_blocks = 0;
636 cmd->policy_hint_size = policy_hint_size;
637 cmd->changed = true;
638
639 r = __create_persistent_data_objects(cmd, may_format_device);
640 if (r) {
641 kfree(cmd);
642 return ERR_PTR(r);
643 }
644
645 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
646 if (r < 0) {
647 dm_cache_metadata_close(cmd);
648 return ERR_PTR(r);
649 }
650
651 return cmd;
652}
653
654void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
655{
656 __destroy_persistent_data_objects(cmd);
657 kfree(cmd);
658}
659
660int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
661{
662 int r;
663 __le64 null_mapping = pack_value(0, 0);
664
665 down_write(&cmd->root_lock);
666 __dm_bless_for_disk(&null_mapping);
667 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
668 from_cblock(new_cache_size),
669 &null_mapping, &cmd->root);
670 if (!r)
671 cmd->cache_blocks = new_cache_size;
672 cmd->changed = true;
673 up_write(&cmd->root_lock);
674
675 return r;
676}
677
678int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
679 sector_t discard_block_size,
680 dm_dblock_t new_nr_entries)
681{
682 int r;
683
684 down_write(&cmd->root_lock);
685 r = dm_bitset_resize(&cmd->discard_info,
686 cmd->discard_root,
687 from_dblock(cmd->discard_nr_blocks),
688 from_dblock(new_nr_entries),
689 false, &cmd->discard_root);
690 if (!r) {
691 cmd->discard_block_size = discard_block_size;
692 cmd->discard_nr_blocks = new_nr_entries;
693 }
694
695 cmd->changed = true;
696 up_write(&cmd->root_lock);
697
698 return r;
699}
700
701static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
702{
703 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
704 from_dblock(b), &cmd->discard_root);
705}
706
707static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
708{
709 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
710 from_dblock(b), &cmd->discard_root);
711}
712
713static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
714 bool *is_discarded)
715{
716 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
717 from_dblock(b), &cmd->discard_root,
718 is_discarded);
719}
720
721static int __discard(struct dm_cache_metadata *cmd,
722 dm_dblock_t dblock, bool discard)
723{
724 int r;
725
726 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
727 if (r)
728 return r;
729
730 cmd->changed = true;
731 return 0;
732}
733
734int dm_cache_set_discard(struct dm_cache_metadata *cmd,
735 dm_dblock_t dblock, bool discard)
736{
737 int r;
738
739 down_write(&cmd->root_lock);
740 r = __discard(cmd, dblock, discard);
741 up_write(&cmd->root_lock);
742
743 return r;
744}
745
746static int __load_discards(struct dm_cache_metadata *cmd,
747 load_discard_fn fn, void *context)
748{
749 int r = 0;
750 dm_block_t b;
751 bool discard;
752
753 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
754 dm_dblock_t dblock = to_dblock(b);
755
756 if (cmd->clean_when_opened) {
757 r = __is_discarded(cmd, dblock, &discard);
758 if (r)
759 return r;
760 } else
761 discard = false;
762
763 r = fn(context, cmd->discard_block_size, dblock, discard);
764 if (r)
765 break;
766 }
767
768 return r;
769}
770
771int dm_cache_load_discards(struct dm_cache_metadata *cmd,
772 load_discard_fn fn, void *context)
773{
774 int r;
775
776 down_read(&cmd->root_lock);
777 r = __load_discards(cmd, fn, context);
778 up_read(&cmd->root_lock);
779
780 return r;
781}
782
783dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd)
784{
785 dm_cblock_t r;
786
787 down_read(&cmd->root_lock);
788 r = cmd->cache_blocks;
789 up_read(&cmd->root_lock);
790
791 return r;
792}
793
794static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
795{
796 int r;
797 __le64 value = pack_value(0, 0);
798
799 __dm_bless_for_disk(&value);
800 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
801 &value, &cmd->root);
802 if (r)
803 return r;
804
805 cmd->changed = true;
806 return 0;
807}
808
809int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
810{
811 int r;
812
813 down_write(&cmd->root_lock);
814 r = __remove(cmd, cblock);
815 up_write(&cmd->root_lock);
816
817 return r;
818}
819
820static int __insert(struct dm_cache_metadata *cmd,
821 dm_cblock_t cblock, dm_oblock_t oblock)
822{
823 int r;
824 __le64 value = pack_value(oblock, M_VALID);
825 __dm_bless_for_disk(&value);
826
827 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
828 &value, &cmd->root);
829 if (r)
830 return r;
831
832 cmd->changed = true;
833 return 0;
834}
835
836int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
837 dm_cblock_t cblock, dm_oblock_t oblock)
838{
839 int r;
840
841 down_write(&cmd->root_lock);
842 r = __insert(cmd, cblock, oblock);
843 up_write(&cmd->root_lock);
844
845 return r;
846}
847
848struct thunk {
849 load_mapping_fn fn;
850 void *context;
851
852 struct dm_cache_metadata *cmd;
853 bool respect_dirty_flags;
854 bool hints_valid;
855};
856
857static bool hints_array_initialized(struct dm_cache_metadata *cmd)
858{
859 return cmd->hint_root && cmd->policy_hint_size;
860}
861
862static bool hints_array_available(struct dm_cache_metadata *cmd,
863 const char *policy_name)
864{
865 bool policy_names_match = !strncmp(cmd->policy_name, policy_name,
866 sizeof(cmd->policy_name));
867
868 return cmd->clean_when_opened && policy_names_match &&
869 hints_array_initialized(cmd);
870}
871
872static int __load_mapping(void *context, uint64_t cblock, void *leaf)
873{
874 int r = 0;
875 bool dirty;
876 __le64 value;
877 __le32 hint_value = 0;
878 dm_oblock_t oblock;
879 unsigned flags;
880 struct thunk *thunk = context;
881 struct dm_cache_metadata *cmd = thunk->cmd;
882
883 memcpy(&value, leaf, sizeof(value));
884 unpack_value(value, &oblock, &flags);
885
886 if (flags & M_VALID) {
887 if (thunk->hints_valid) {
888 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,
889 cblock, &hint_value);
890 if (r && r != -ENODATA)
891 return r;
892 }
893
894 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;
895 r = thunk->fn(thunk->context, oblock, to_cblock(cblock),
896 dirty, le32_to_cpu(hint_value), thunk->hints_valid);
897 }
898
899 return r;
900}
901
902static int __load_mappings(struct dm_cache_metadata *cmd, const char *policy_name,
903 load_mapping_fn fn, void *context)
904{
905 struct thunk thunk;
906
907 thunk.fn = fn;
908 thunk.context = context;
909
910 thunk.cmd = cmd;
911 thunk.respect_dirty_flags = cmd->clean_when_opened;
912 thunk.hints_valid = hints_array_available(cmd, policy_name);
913
914 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);
915}
916
917int dm_cache_load_mappings(struct dm_cache_metadata *cmd, const char *policy_name,
918 load_mapping_fn fn, void *context)
919{
920 int r;
921
922 down_read(&cmd->root_lock);
923 r = __load_mappings(cmd, policy_name, fn, context);
924 up_read(&cmd->root_lock);
925
926 return r;
927}
928
929static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
930{
931 int r = 0;
932 __le64 value;
933 dm_oblock_t oblock;
934 unsigned flags;
935
936 memcpy(&value, leaf, sizeof(value));
937 unpack_value(value, &oblock, &flags);
938
939 return r;
940}
941
942static int __dump_mappings(struct dm_cache_metadata *cmd)
943{
944 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
945}
946
947void dm_cache_dump(struct dm_cache_metadata *cmd)
948{
949 down_read(&cmd->root_lock);
950 __dump_mappings(cmd);
951 up_read(&cmd->root_lock);
952}
953
954int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
955{
956 int r;
957
958 down_read(&cmd->root_lock);
959 r = cmd->changed;
960 up_read(&cmd->root_lock);
961
962 return r;
963}
964
965static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
966{
967 int r;
968 unsigned flags;
969 dm_oblock_t oblock;
970 __le64 value;
971
972 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
973 if (r)
974 return r;
975
976 unpack_value(value, &oblock, &flags);
977
978 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
979 /* nothing to be done */
980 return 0;
981
79ed9caf 982 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
c6b4fcba
JT		 983 __dm_bless_for_disk(&value);
984
985 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
986 &value, &cmd->root);
987 if (r)
988 return r;
989
990 cmd->changed = true;
991 return 0;
992
993}
994
995int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
996 dm_cblock_t cblock, bool dirty)
997{
998 int r;
999
1000 down_write(&cmd->root_lock);
1001 r = __dirty(cmd, cblock, dirty);
1002 up_write(&cmd->root_lock);
1003
1004 return r;
1005}
1006
1007void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1008 struct dm_cache_statistics *stats)
1009{
1010 down_read(&cmd->root_lock);
1011 memcpy(stats, &cmd->stats, sizeof(*stats));
1012 up_read(&cmd->root_lock);
1013}
1014
1015void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1016 struct dm_cache_statistics *stats)
1017{
1018 down_write(&cmd->root_lock);
1019 memcpy(&cmd->stats, stats, sizeof(*stats));
1020 up_write(&cmd->root_lock);
1021}
1022
1023int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1024{
1025 int r;
1026 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1027 clear_clean_shutdown);
1028
1029 down_write(&cmd->root_lock);
1030 r = __commit_transaction(cmd, mutator);
1031 if (r)
1032 goto out;
1033
1034 r = __begin_transaction(cmd);
1035
1036out:
1037 up_write(&cmd->root_lock);
1038 return r;
1039}
1040
1041int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1042 dm_block_t *result)
1043{
1044 int r = -EINVAL;
1045
1046 down_read(&cmd->root_lock);
1047 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1048 up_read(&cmd->root_lock);
1049
1050 return r;
1051}
1052
1053int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1054 dm_block_t *result)
1055{
1056 int r = -EINVAL;
1057
1058 down_read(&cmd->root_lock);
1059 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1060 up_read(&cmd->root_lock);
1061
1062 return r;
1063}
1064
1065/*----------------------------------------------------------------*/
1066
1067static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1068{
1069 int r;
1070 __le32 value;
1071 size_t hint_size;
1072 const char *policy_name = dm_cache_policy_get_name(policy);
1073
1074 if (!policy_name[0] ||
1075 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1076 return -EINVAL;
1077
1078 if (strcmp(cmd->policy_name, policy_name)) {
1079 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1080
1081 hint_size = dm_cache_policy_get_hint_size(policy);
1082 if (!hint_size)
1083 return 0; /* short-circuit hints initialization */
1084 cmd->policy_hint_size = hint_size;
1085
1086 if (cmd->hint_root) {
1087 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1088 if (r)
1089 return r;
1090 }
1091
1092 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root);
1093 if (r)
1094 return r;
1095
1096 value = cpu_to_le32(0);
1097 __dm_bless_for_disk(&value);
1098 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0,
1099 from_cblock(cmd->cache_blocks),
1100 &value, &cmd->hint_root);
1101 if (r)
1102 return r;
1103 }
1104
1105 return 0;
1106}
1107
1108int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1109{
1110 int r;
1111
1112 down_write(&cmd->root_lock);
1113 r = begin_hints(cmd, policy);
1114 up_write(&cmd->root_lock);
1115
1116 return r;
1117}
1118
1119static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock,
1120 uint32_t hint)
1121{
1122 int r;
1123 __le32 value = cpu_to_le32(hint);
1124 __dm_bless_for_disk(&value);
1125
1126 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
1127 from_cblock(cblock), &value, &cmd->hint_root);
1128 cmd->changed = true;
1129
1130 return r;
1131}
1132
1133int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock,
1134 uint32_t hint)
1135{
1136 int r;
1137
1138 if (!hints_array_initialized(cmd))
1139 return 0;
1140
1141 down_write(&cmd->root_lock);
1142 r = save_hint(cmd, cblock, hint);
1143 up_write(&cmd->root_lock);
1144
1145 return r;
1146}
Linux 6.x block layer and io_uring tree(s)