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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Red Hat, Inc.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm-cache-metadata.h"
9
10#include "persistent-data/dm-array.h"
11#include "persistent-data/dm-bitset.h"
12#include "persistent-data/dm-space-map.h"
13#include "persistent-data/dm-space-map-disk.h"
14#include "persistent-data/dm-transaction-manager.h"
15
16#include <linux/device-mapper.h>
17#include <linux/refcount.h>
18
19/*----------------------------------------------------------------*/
20
21#define DM_MSG_PREFIX "cache metadata"
22
23#define CACHE_SUPERBLOCK_MAGIC 06142003
24#define CACHE_SUPERBLOCK_LOCATION 0
25
26/*
27 * defines a range of metadata versions that this module can handle.
28 */
29#define MIN_CACHE_VERSION 1
30#define MAX_CACHE_VERSION 2
31
32/*
33 * 3 for btree insert +
34 * 2 for btree lookup used within space map
35 */
36#define CACHE_MAX_CONCURRENT_LOCKS 5
37#define SPACE_MAP_ROOT_SIZE 128
38
39enum superblock_flag_bits {
40 /* for spotting crashes that would invalidate the dirty bitset */
41 CLEAN_SHUTDOWN,
42 /* metadata must be checked using the tools */
43 NEEDS_CHECK,
44};
45
46/*
47 * Each mapping from cache block -> origin block carries a set of flags.
48 */
49enum mapping_bits {
50 /*
51 * A valid mapping. Because we're using an array we clear this
52 * flag for an non existant mapping.
53 */
54 M_VALID = 1,
55
56 /*
57 * The data on the cache is different from that on the origin.
58 * This flag is only used by metadata format 1.
59 */
60 M_DIRTY = 2
61};
62
63struct cache_disk_superblock {
64 __le32 csum;
65 __le32 flags;
66 __le64 blocknr;
67
68 __u8 uuid[16];
69 __le64 magic;
70 __le32 version;
71
72 __u8 policy_name[CACHE_POLICY_NAME_SIZE];
73 __le32 policy_hint_size;
74
75 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
76 __le64 mapping_root;
77 __le64 hint_root;
78
79 __le64 discard_root;
80 __le64 discard_block_size;
81 __le64 discard_nr_blocks;
82
83 __le32 data_block_size;
84 __le32 metadata_block_size;
85 __le32 cache_blocks;
86
87 __le32 compat_flags;
88 __le32 compat_ro_flags;
89 __le32 incompat_flags;
90
91 __le32 read_hits;
92 __le32 read_misses;
93 __le32 write_hits;
94 __le32 write_misses;
95
96 __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
97
98 /*
99 * Metadata format 2 fields.
100 */
101 __le64 dirty_root;
102} __packed;
103
104struct dm_cache_metadata {
105 refcount_t ref_count;
106 struct list_head list;
107
108 unsigned int version;
109 struct block_device *bdev;
110 struct dm_block_manager *bm;
111 struct dm_space_map *metadata_sm;
112 struct dm_transaction_manager *tm;
113
114 struct dm_array_info info;
115 struct dm_array_info hint_info;
116 struct dm_disk_bitset discard_info;
117
118 struct rw_semaphore root_lock;
119 unsigned long flags;
120 dm_block_t root;
121 dm_block_t hint_root;
122 dm_block_t discard_root;
123
124 sector_t discard_block_size;
125 dm_dblock_t discard_nr_blocks;
126
127 sector_t data_block_size;
128 dm_cblock_t cache_blocks;
129 bool changed:1;
130 bool clean_when_opened:1;
131
132 char policy_name[CACHE_POLICY_NAME_SIZE];
133 unsigned int policy_version[CACHE_POLICY_VERSION_SIZE];
134 size_t policy_hint_size;
135 struct dm_cache_statistics stats;
136
137 /*
138 * Reading the space map root can fail, so we read it into this
139 * buffer before the superblock is locked and updated.
140 */
141 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
142
143 /*
144 * Set if a transaction has to be aborted but the attempt to roll
145 * back to the previous (good) transaction failed. The only
146 * metadata operation permissible in this state is the closing of
147 * the device.
148 */
149 bool fail_io:1;
150
151 /*
152 * Metadata format 2 fields.
153 */
154 dm_block_t dirty_root;
155 struct dm_disk_bitset dirty_info;
156
157 /*
158 * These structures are used when loading metadata. They're too
159 * big to put on the stack.
160 */
161 struct dm_array_cursor mapping_cursor;
162 struct dm_array_cursor hint_cursor;
163 struct dm_bitset_cursor dirty_cursor;
164};
165
166/*
167 *-----------------------------------------------------------------
168 * superblock validator
169 *-----------------------------------------------------------------
170 */
171#define SUPERBLOCK_CSUM_XOR 9031977
172
173static void sb_prepare_for_write(const struct dm_block_validator *v,
174 struct dm_block *b,
175 size_t sb_block_size)
176{
177 struct cache_disk_superblock *disk_super = dm_block_data(b);
178
179 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
180 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
181 sb_block_size - sizeof(__le32),
182 SUPERBLOCK_CSUM_XOR));
183}
184
185static int check_metadata_version(struct cache_disk_superblock *disk_super)
186{
187 uint32_t metadata_version = le32_to_cpu(disk_super->version);
188
189 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
190 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
191 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
192 return -EINVAL;
193 }
194
195 return 0;
196}
197
198static int sb_check(const struct dm_block_validator *v,
199 struct dm_block *b,
200 size_t sb_block_size)
201{
202 struct cache_disk_superblock *disk_super = dm_block_data(b);
203 __le32 csum_le;
204
205 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
206 DMERR("%s failed: blocknr %llu: wanted %llu",
207 __func__, le64_to_cpu(disk_super->blocknr),
208 (unsigned long long)dm_block_location(b));
209 return -ENOTBLK;
210 }
211
212 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
213 DMERR("%s failed: magic %llu: wanted %llu",
214 __func__, le64_to_cpu(disk_super->magic),
215 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
216 return -EILSEQ;
217 }
218
219 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
220 sb_block_size - sizeof(__le32),
221 SUPERBLOCK_CSUM_XOR));
222 if (csum_le != disk_super->csum) {
223 DMERR("%s failed: csum %u: wanted %u",
224 __func__, le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
225 return -EILSEQ;
226 }
227
228 return check_metadata_version(disk_super);
229}
230
231static const struct dm_block_validator sb_validator = {
232 .name = "superblock",
233 .prepare_for_write = sb_prepare_for_write,
234 .check = sb_check
235};
236
237/*----------------------------------------------------------------*/
238
239static int superblock_read_lock(struct dm_cache_metadata *cmd,
240 struct dm_block **sblock)
241{
242 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
243 &sb_validator, sblock);
244}
245
246static int superblock_lock_zero(struct dm_cache_metadata *cmd,
247 struct dm_block **sblock)
248{
249 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
250 &sb_validator, sblock);
251}
252
253static int superblock_lock(struct dm_cache_metadata *cmd,
254 struct dm_block **sblock)
255{
256 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
257 &sb_validator, sblock);
258}
259
260/*----------------------------------------------------------------*/
261
262static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
263{
264 int r;
265 unsigned int i;
266 struct dm_block *b;
267 __le64 *data_le, zero = cpu_to_le64(0);
268 unsigned int sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
269
270 /*
271 * We can't use a validator here - it may be all zeroes.
272 */
273 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
274 if (r)
275 return r;
276
277 data_le = dm_block_data(b);
278 *result = true;
279 for (i = 0; i < sb_block_size; i++) {
280 if (data_le[i] != zero) {
281 *result = false;
282 break;
283 }
284 }
285
286 dm_bm_unlock(b);
287
288 return 0;
289}
290
291static void __setup_mapping_info(struct dm_cache_metadata *cmd)
292{
293 struct dm_btree_value_type vt;
294
295 vt.context = NULL;
296 vt.size = sizeof(__le64);
297 vt.inc = NULL;
298 vt.dec = NULL;
299 vt.equal = NULL;
300 dm_array_info_init(&cmd->info, cmd->tm, &vt);
301
302 if (cmd->policy_hint_size) {
303 vt.size = sizeof(__le32);
304 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
305 }
306}
307
308static int __save_sm_root(struct dm_cache_metadata *cmd)
309{
310 int r;
311 size_t metadata_len;
312
313 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
314 if (r < 0)
315 return r;
316
317 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
318 metadata_len);
319}
320
321static void __copy_sm_root(struct dm_cache_metadata *cmd,
322 struct cache_disk_superblock *disk_super)
323{
324 memcpy(&disk_super->metadata_space_map_root,
325 &cmd->metadata_space_map_root,
326 sizeof(cmd->metadata_space_map_root));
327}
328
329static bool separate_dirty_bits(struct dm_cache_metadata *cmd)
330{
331 return cmd->version >= 2;
332}
333
334static int __write_initial_superblock(struct dm_cache_metadata *cmd)
335{
336 int r;
337 struct dm_block *sblock;
338 struct cache_disk_superblock *disk_super;
339 sector_t bdev_size = bdev_nr_sectors(cmd->bdev);
340
341 /* FIXME: see if we can lose the max sectors limit */
342 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
343 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
344
345 r = dm_tm_pre_commit(cmd->tm);
346 if (r < 0)
347 return r;
348
349 /*
350 * dm_sm_copy_root() can fail. So we need to do it before we start
351 * updating the superblock.
352 */
353 r = __save_sm_root(cmd);
354 if (r)
355 return r;
356
357 r = superblock_lock_zero(cmd, &sblock);
358 if (r)
359 return r;
360
361 disk_super = dm_block_data(sblock);
362 disk_super->flags = 0;
363 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
364 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
365 disk_super->version = cpu_to_le32(cmd->version);
366 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
367 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
368 disk_super->policy_hint_size = cpu_to_le32(0);
369
370 __copy_sm_root(cmd, disk_super);
371
372 disk_super->mapping_root = cpu_to_le64(cmd->root);
373 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
374 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
375 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
376 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
377 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
378 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
379 disk_super->cache_blocks = cpu_to_le32(0);
380
381 disk_super->read_hits = cpu_to_le32(0);
382 disk_super->read_misses = cpu_to_le32(0);
383 disk_super->write_hits = cpu_to_le32(0);
384 disk_super->write_misses = cpu_to_le32(0);
385
386 if (separate_dirty_bits(cmd))
387 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
388
389 return dm_tm_commit(cmd->tm, sblock);
390}
391
392static int __format_metadata(struct dm_cache_metadata *cmd)
393{
394 int r;
395
396 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
397 &cmd->tm, &cmd->metadata_sm);
398 if (r < 0) {
399 DMERR("tm_create_with_sm failed");
400 return r;
401 }
402
403 __setup_mapping_info(cmd);
404
405 r = dm_array_empty(&cmd->info, &cmd->root);
406 if (r < 0)
407 goto bad;
408
409 if (separate_dirty_bits(cmd)) {
410 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
411 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root);
412 if (r < 0)
413 goto bad;
414 }
415
416 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
417 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
418 if (r < 0)
419 goto bad;
420
421 cmd->discard_block_size = 0;
422 cmd->discard_nr_blocks = 0;
423
424 r = __write_initial_superblock(cmd);
425 if (r)
426 goto bad;
427
428 cmd->clean_when_opened = true;
429 return 0;
430
431bad:
432 dm_tm_destroy(cmd->tm);
433 dm_sm_destroy(cmd->metadata_sm);
434
435 return r;
436}
437
438static int __check_incompat_features(struct cache_disk_superblock *disk_super,
439 struct dm_cache_metadata *cmd)
440{
441 uint32_t incompat_flags, features;
442
443 incompat_flags = le32_to_cpu(disk_super->incompat_flags);
444 features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
445 if (features) {
446 DMERR("could not access metadata due to unsupported optional features (%lx).",
447 (unsigned long)features);
448 return -EINVAL;
449 }
450
451 /*
452 * Check for read-only metadata to skip the following RDWR checks.
453 */
454 if (bdev_read_only(cmd->bdev))
455 return 0;
456
457 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
458 if (features) {
459 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
460 (unsigned long)features);
461 return -EINVAL;
462 }
463
464 return 0;
465}
466
467static int __open_metadata(struct dm_cache_metadata *cmd)
468{
469 int r;
470 struct dm_block *sblock;
471 struct cache_disk_superblock *disk_super;
472 unsigned long sb_flags;
473
474 r = superblock_read_lock(cmd, &sblock);
475 if (r < 0) {
476 DMERR("couldn't read lock superblock");
477 return r;
478 }
479
480 disk_super = dm_block_data(sblock);
481
482 /* Verify the data block size hasn't changed */
483 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
484 DMERR("changing the data block size (from %u to %llu) is not supported",
485 le32_to_cpu(disk_super->data_block_size),
486 (unsigned long long)cmd->data_block_size);
487 r = -EINVAL;
488 goto bad;
489 }
490
491 r = __check_incompat_features(disk_super, cmd);
492 if (r < 0)
493 goto bad;
494
495 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
496 disk_super->metadata_space_map_root,
497 sizeof(disk_super->metadata_space_map_root),
498 &cmd->tm, &cmd->metadata_sm);
499 if (r < 0) {
500 DMERR("tm_open_with_sm failed");
501 goto bad;
502 }
503
504 __setup_mapping_info(cmd);
505 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
506 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
507 sb_flags = le32_to_cpu(disk_super->flags);
508 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
509 dm_bm_unlock(sblock);
510
511 return 0;
512
513bad:
514 dm_bm_unlock(sblock);
515 return r;
516}
517
518static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
519 bool format_device)
520{
521 int r;
522 bool unformatted = false;
523
524 r = __superblock_all_zeroes(cmd->bm, &unformatted);
525 if (r)
526 return r;
527
528 if (unformatted)
529 return format_device ? __format_metadata(cmd) : -EPERM;
530
531 return __open_metadata(cmd);
532}
533
534static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
535 bool may_format_device)
536{
537 int r;
538
539 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
540 CACHE_MAX_CONCURRENT_LOCKS);
541 if (IS_ERR(cmd->bm)) {
542 DMERR("could not create block manager");
543 r = PTR_ERR(cmd->bm);
544 cmd->bm = NULL;
545 return r;
546 }
547
548 r = __open_or_format_metadata(cmd, may_format_device);
549 if (r) {
550 dm_block_manager_destroy(cmd->bm);
551 cmd->bm = NULL;
552 }
553
554 return r;
555}
556
557static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd,
558 bool destroy_bm)
559{
560 dm_sm_destroy(cmd->metadata_sm);
561 dm_tm_destroy(cmd->tm);
562 if (destroy_bm)
563 dm_block_manager_destroy(cmd->bm);
564}
565
566typedef unsigned long (*flags_mutator)(unsigned long);
567
568static void update_flags(struct cache_disk_superblock *disk_super,
569 flags_mutator mutator)
570{
571 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
572
573 disk_super->flags = cpu_to_le32(sb_flags);
574}
575
576static unsigned long set_clean_shutdown(unsigned long flags)
577{
578 set_bit(CLEAN_SHUTDOWN, &flags);
579 return flags;
580}
581
582static unsigned long clear_clean_shutdown(unsigned long flags)
583{
584 clear_bit(CLEAN_SHUTDOWN, &flags);
585 return flags;
586}
587
588static void read_superblock_fields(struct dm_cache_metadata *cmd,
589 struct cache_disk_superblock *disk_super)
590{
591 cmd->version = le32_to_cpu(disk_super->version);
592 cmd->flags = le32_to_cpu(disk_super->flags);
593 cmd->root = le64_to_cpu(disk_super->mapping_root);
594 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
595 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
596 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
597 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
598 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
599 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
600 strscpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
601 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
602 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
603 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
604 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
605
606 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
607 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
608 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
609 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
610
611 if (separate_dirty_bits(cmd))
612 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
613
614 cmd->changed = false;
615}
616
617/*
618 * The mutator updates the superblock flags.
619 */
620static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
621 flags_mutator mutator)
622{
623 int r;
624 struct cache_disk_superblock *disk_super;
625 struct dm_block *sblock;
626
627 r = superblock_lock(cmd, &sblock);
628 if (r)
629 return r;
630
631 disk_super = dm_block_data(sblock);
632 update_flags(disk_super, mutator);
633 read_superblock_fields(cmd, disk_super);
634 dm_bm_unlock(sblock);
635
636 return dm_bm_flush(cmd->bm);
637}
638
639static int __begin_transaction(struct dm_cache_metadata *cmd)
640{
641 int r;
642 struct cache_disk_superblock *disk_super;
643 struct dm_block *sblock;
644
645 /*
646 * We re-read the superblock every time. Shouldn't need to do this
647 * really.
648 */
649 r = superblock_read_lock(cmd, &sblock);
650 if (r)
651 return r;
652
653 disk_super = dm_block_data(sblock);
654 read_superblock_fields(cmd, disk_super);
655 dm_bm_unlock(sblock);
656
657 return 0;
658}
659
660static int __commit_transaction(struct dm_cache_metadata *cmd,
661 flags_mutator mutator)
662{
663 int r;
664 struct cache_disk_superblock *disk_super;
665 struct dm_block *sblock;
666
667 /*
668 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
669 */
670 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
671
672 if (separate_dirty_bits(cmd)) {
673 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
674 &cmd->dirty_root);
675 if (r)
676 return r;
677 }
678
679 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
680 &cmd->discard_root);
681 if (r)
682 return r;
683
684 r = dm_tm_pre_commit(cmd->tm);
685 if (r < 0)
686 return r;
687
688 r = __save_sm_root(cmd);
689 if (r)
690 return r;
691
692 r = superblock_lock(cmd, &sblock);
693 if (r)
694 return r;
695
696 disk_super = dm_block_data(sblock);
697
698 disk_super->flags = cpu_to_le32(cmd->flags);
699 if (mutator)
700 update_flags(disk_super, mutator);
701
702 disk_super->mapping_root = cpu_to_le64(cmd->root);
703 if (separate_dirty_bits(cmd))
704 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
705 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
706 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
707 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
708 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
709 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
710 strscpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
711 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
712 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
713 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
714 disk_super->policy_hint_size = cpu_to_le32(cmd->policy_hint_size);
715
716 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
717 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
718 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
719 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
720 __copy_sm_root(cmd, disk_super);
721
722 return dm_tm_commit(cmd->tm, sblock);
723}
724
725/*----------------------------------------------------------------*/
726
727/*
728 * The mappings are held in a dm-array that has 64-bit values stored in
729 * little-endian format. The index is the cblock, the high 48bits of the
730 * value are the oblock and the low 16 bit the flags.
731 */
732#define FLAGS_MASK ((1 << 16) - 1)
733
734static __le64 pack_value(dm_oblock_t block, unsigned int flags)
735{
736 uint64_t value = from_oblock(block);
737
738 value <<= 16;
739 value = value | (flags & FLAGS_MASK);
740 return cpu_to_le64(value);
741}
742
743static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned int *flags)
744{
745 uint64_t value = le64_to_cpu(value_le);
746 uint64_t b = value >> 16;
747
748 *block = to_oblock(b);
749 *flags = value & FLAGS_MASK;
750}
751
752/*----------------------------------------------------------------*/
753
754static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
755 sector_t data_block_size,
756 bool may_format_device,
757 size_t policy_hint_size,
758 unsigned int metadata_version)
759{
760 int r;
761 struct dm_cache_metadata *cmd;
762
763 cmd = kzalloc_obj(*cmd);
764 if (!cmd) {
765 DMERR("could not allocate metadata struct");
766 return ERR_PTR(-ENOMEM);
767 }
768
769 cmd->version = metadata_version;
770 refcount_set(&cmd->ref_count, 1);
771 init_rwsem(&cmd->root_lock);
772 cmd->bdev = bdev;
773 cmd->data_block_size = data_block_size;
774 cmd->cache_blocks = 0;
775 cmd->policy_hint_size = policy_hint_size;
776 cmd->changed = true;
777 cmd->fail_io = false;
778
779 r = __create_persistent_data_objects(cmd, may_format_device);
780 if (r) {
781 kfree(cmd);
782 return ERR_PTR(r);
783 }
784
785 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
786 if (r < 0) {
787 dm_cache_metadata_close(cmd);
788 return ERR_PTR(r);
789 }
790
791 return cmd;
792}
793
794/*
795 * We keep a little list of ref counted metadata objects to prevent two
796 * different target instances creating separate bufio instances. This is
797 * an issue if a table is reloaded before the suspend.
798 */
799static DEFINE_MUTEX(table_lock);
800static LIST_HEAD(table);
801
802static struct dm_cache_metadata *lookup(struct block_device *bdev)
803{
804 struct dm_cache_metadata *cmd;
805
806 list_for_each_entry(cmd, &table, list)
807 if (cmd->bdev == bdev) {
808 refcount_inc(&cmd->ref_count);
809 return cmd;
810 }
811
812 return NULL;
813}
814
815static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
816 sector_t data_block_size,
817 bool may_format_device,
818 size_t policy_hint_size,
819 unsigned int metadata_version)
820{
821 struct dm_cache_metadata *cmd, *cmd2;
822
823 mutex_lock(&table_lock);
824 cmd = lookup(bdev);
825 mutex_unlock(&table_lock);
826
827 if (cmd)
828 return cmd;
829
830 cmd = metadata_open(bdev, data_block_size, may_format_device,
831 policy_hint_size, metadata_version);
832 if (!IS_ERR(cmd)) {
833 mutex_lock(&table_lock);
834 cmd2 = lookup(bdev);
835 if (cmd2) {
836 mutex_unlock(&table_lock);
837 __destroy_persistent_data_objects(cmd, true);
838 kfree(cmd);
839 return cmd2;
840 }
841 list_add(&cmd->list, &table);
842 mutex_unlock(&table_lock);
843 }
844
845 return cmd;
846}
847
848static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
849{
850 if (cmd->data_block_size != data_block_size) {
851 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
852 (unsigned long long) data_block_size,
853 (unsigned long long) cmd->data_block_size);
854 return false;
855 }
856
857 return true;
858}
859
860struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
861 sector_t data_block_size,
862 bool may_format_device,
863 size_t policy_hint_size,
864 unsigned int metadata_version)
865{
866 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
867 policy_hint_size, metadata_version);
868
869 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
870 dm_cache_metadata_close(cmd);
871 return ERR_PTR(-EINVAL);
872 }
873
874 return cmd;
875}
876
877void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
878{
879 if (refcount_dec_and_test(&cmd->ref_count)) {
880 mutex_lock(&table_lock);
881 list_del(&cmd->list);
882 mutex_unlock(&table_lock);
883
884 if (!cmd->fail_io)
885 __destroy_persistent_data_objects(cmd, true);
886 kfree(cmd);
887 }
888}
889
890/*
891 * Checks that the given cache block is either unmapped or clean.
892 */
893static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
894 bool *result)
895{
896 int r;
897 __le64 value;
898 dm_oblock_t ob;
899 unsigned int flags;
900
901 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
902 if (r)
903 return r;
904
905 unpack_value(value, &ob, &flags);
906 *result = !((flags & M_VALID) && (flags & M_DIRTY));
907
908 return 0;
909}
910
911static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
912 dm_cblock_t begin, dm_cblock_t end,
913 bool *result)
914{
915 int r;
916 *result = true;
917
918 while (begin != end) {
919 r = block_clean_combined_dirty(cmd, begin, result);
920 if (r) {
921 DMERR("block_clean_combined_dirty failed");
922 return r;
923 }
924
925 if (!*result) {
926 DMERR("cache block %llu is dirty",
927 (unsigned long long) from_cblock(begin));
928 return 0;
929 }
930
931 begin = to_cblock(from_cblock(begin) + 1);
932 }
933
934 return 0;
935}
936
937static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
938 dm_cblock_t begin, dm_cblock_t end,
939 bool *result)
940{
941 int r;
942 bool dirty_flag;
943 *result = true;
944
945 if (from_cblock(cmd->cache_blocks) == 0)
946 /* Nothing to do */
947 return 0;
948
949 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
950 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
951 if (r) {
952 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__);
953 return r;
954 }
955
956 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin));
957 if (r) {
958 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
959 dm_bitset_cursor_end(&cmd->dirty_cursor);
960 return r;
961 }
962
963 while (begin != end) {
964 /*
965 * We assume that unmapped blocks have their dirty bit
966 * cleared.
967 */
968 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor);
969 if (dirty_flag) {
970 DMERR("%s: cache block %llu is dirty", __func__,
971 (unsigned long long) from_cblock(begin));
972 dm_bitset_cursor_end(&cmd->dirty_cursor);
973 *result = false;
974 return 0;
975 }
976
977 begin = to_cblock(from_cblock(begin) + 1);
978 if (begin == end)
979 break;
980
981 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
982 if (r) {
983 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
984 dm_bitset_cursor_end(&cmd->dirty_cursor);
985 return r;
986 }
987 }
988
989 dm_bitset_cursor_end(&cmd->dirty_cursor);
990
991 return 0;
992}
993
994static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
995 dm_cblock_t begin, dm_cblock_t end,
996 bool *result)
997{
998 if (separate_dirty_bits(cmd))
999 return blocks_are_clean_separate_dirty(cmd, begin, end, result);
1000 else
1001 return blocks_are_clean_combined_dirty(cmd, begin, end, result);
1002}
1003
1004static bool cmd_write_lock(struct dm_cache_metadata *cmd)
1005{
1006 down_write(&cmd->root_lock);
1007 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
1008 up_write(&cmd->root_lock);
1009 return false;
1010 }
1011 return true;
1012}
1013
1014#define WRITE_LOCK(cmd) \
1015 do { \
1016 if (!cmd_write_lock((cmd))) \
1017 return -EINVAL; \
1018 } while (0)
1019
1020#define WRITE_LOCK_VOID(cmd) \
1021 do { \
1022 if (!cmd_write_lock((cmd))) \
1023 return; \
1024 } while (0)
1025
1026#define WRITE_LOCK_OR_GOTO(cmd, label) \
1027 do { \
1028 if (!cmd_write_lock((cmd))) \
1029 goto label; \
1030 } while (0)
1031
1032#define WRITE_UNLOCK(cmd) \
1033 up_write(&(cmd)->root_lock)
1034
1035static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1036{
1037 down_read(&cmd->root_lock);
1038 if (cmd->fail_io) {
1039 up_read(&cmd->root_lock);
1040 return false;
1041 }
1042 return true;
1043}
1044
1045#define READ_LOCK(cmd) \
1046 do { \
1047 if (!cmd_read_lock((cmd))) \
1048 return -EINVAL; \
1049 } while (0)
1050
1051#define READ_LOCK_VOID(cmd) \
1052 do { \
1053 if (!cmd_read_lock((cmd))) \
1054 return; \
1055 } while (0)
1056
1057#define READ_UNLOCK(cmd) \
1058 up_read(&(cmd)->root_lock)
1059
1060int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1061{
1062 int r;
1063 bool clean;
1064 __le64 null_mapping = pack_value(0, 0);
1065
1066 WRITE_LOCK(cmd);
1067 __dm_bless_for_disk(&null_mapping);
1068
1069 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1070 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
1071 if (r) {
1072 __dm_unbless_for_disk(&null_mapping);
1073 goto out;
1074 }
1075
1076 if (!clean) {
1077 DMERR("unable to shrink cache due to dirty blocks");
1078 r = -EINVAL;
1079 __dm_unbless_for_disk(&null_mapping);
1080 goto out;
1081 }
1082 }
1083
1084 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1085 from_cblock(new_cache_size),
1086 &null_mapping, &cmd->root);
1087 if (r)
1088 goto out;
1089
1090 if (separate_dirty_bits(cmd)) {
1091 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1092 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1093 false, &cmd->dirty_root);
1094 if (r)
1095 goto out;
1096 }
1097
1098 cmd->cache_blocks = new_cache_size;
1099 cmd->changed = true;
1100
1101out:
1102 WRITE_UNLOCK(cmd);
1103
1104 return r;
1105}
1106
1107int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1108 sector_t discard_block_size,
1109 dm_dblock_t new_nr_entries)
1110{
1111 int r;
1112
1113 WRITE_LOCK(cmd);
1114 r = dm_bitset_resize(&cmd->discard_info,
1115 cmd->discard_root,
1116 from_dblock(cmd->discard_nr_blocks),
1117 from_dblock(new_nr_entries),
1118 false, &cmd->discard_root);
1119 if (!r) {
1120 cmd->discard_block_size = discard_block_size;
1121 cmd->discard_nr_blocks = new_nr_entries;
1122 }
1123
1124 cmd->changed = true;
1125 WRITE_UNLOCK(cmd);
1126
1127 return r;
1128}
1129
1130static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1131{
1132 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
1133 from_dblock(b), &cmd->discard_root);
1134}
1135
1136static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1137{
1138 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
1139 from_dblock(b), &cmd->discard_root);
1140}
1141
1142static int __discard(struct dm_cache_metadata *cmd,
1143 dm_dblock_t dblock, bool discard)
1144{
1145 int r;
1146
1147 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1148 if (r)
1149 return r;
1150
1151 cmd->changed = true;
1152 return 0;
1153}
1154
1155int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1156 dm_dblock_t dblock, bool discard)
1157{
1158 int r;
1159
1160 WRITE_LOCK(cmd);
1161 r = __discard(cmd, dblock, discard);
1162 WRITE_UNLOCK(cmd);
1163
1164 return r;
1165}
1166
1167static int __load_discards(struct dm_cache_metadata *cmd,
1168 load_discard_fn fn, void *context)
1169{
1170 int r = 0;
1171 uint32_t b;
1172 struct dm_bitset_cursor c;
1173
1174 if (from_dblock(cmd->discard_nr_blocks) == 0)
1175 /* nothing to do */
1176 return 0;
1177
1178 if (cmd->clean_when_opened) {
1179 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1180 if (r)
1181 return r;
1182
1183 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1184 from_dblock(cmd->discard_nr_blocks), &c);
1185 if (r)
1186 return r;
1187
1188 for (b = 0; ; b++) {
1189 r = fn(context, cmd->discard_block_size, to_dblock(b),
1190 dm_bitset_cursor_get_value(&c));
1191 if (r)
1192 break;
1193
1194 if (b >= (from_dblock(cmd->discard_nr_blocks) - 1))
1195 break;
1196
1197 r = dm_bitset_cursor_next(&c);
1198 if (r)
1199 break;
1200 }
1201
1202 dm_bitset_cursor_end(&c);
1203
1204 } else {
1205 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1206 r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1207 if (r)
1208 return r;
1209 }
1210 }
1211
1212 return r;
1213}
1214
1215int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1216 load_discard_fn fn, void *context)
1217{
1218 int r;
1219
1220 READ_LOCK(cmd);
1221 r = __load_discards(cmd, fn, context);
1222 READ_UNLOCK(cmd);
1223
1224 return r;
1225}
1226
1227static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1228{
1229 int r;
1230 __le64 value = pack_value(0, 0);
1231
1232 __dm_bless_for_disk(&value);
1233 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1234 &value, &cmd->root);
1235 if (r)
1236 return r;
1237
1238 cmd->changed = true;
1239 return 0;
1240}
1241
1242int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1243{
1244 int r;
1245
1246 WRITE_LOCK(cmd);
1247 r = __remove(cmd, cblock);
1248 WRITE_UNLOCK(cmd);
1249
1250 return r;
1251}
1252
1253static int __insert(struct dm_cache_metadata *cmd,
1254 dm_cblock_t cblock, dm_oblock_t oblock)
1255{
1256 int r;
1257 __le64 value = pack_value(oblock, M_VALID);
1258
1259 __dm_bless_for_disk(&value);
1260
1261 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1262 &value, &cmd->root);
1263 if (r)
1264 return r;
1265
1266 cmd->changed = true;
1267 return 0;
1268}
1269
1270int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1271 dm_cblock_t cblock, dm_oblock_t oblock)
1272{
1273 int r;
1274
1275 WRITE_LOCK(cmd);
1276 r = __insert(cmd, cblock, oblock);
1277 WRITE_UNLOCK(cmd);
1278
1279 return r;
1280}
1281
1282static bool policy_unchanged(struct dm_cache_metadata *cmd,
1283 struct dm_cache_policy *policy)
1284{
1285 const char *policy_name = dm_cache_policy_get_name(policy);
1286 const unsigned int *policy_version = dm_cache_policy_get_version(policy);
1287 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1288
1289 /*
1290 * Ensure policy names match.
1291 */
1292 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1293 return false;
1294
1295 /*
1296 * Ensure policy major versions match.
1297 */
1298 if (cmd->policy_version[0] != policy_version[0])
1299 return false;
1300
1301 /*
1302 * Ensure policy hint sizes match.
1303 */
1304 if (cmd->policy_hint_size != policy_hint_size)
1305 return false;
1306
1307 return true;
1308}
1309
1310static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1311{
1312 return cmd->hint_root && cmd->policy_hint_size;
1313}
1314
1315static bool hints_array_available(struct dm_cache_metadata *cmd,
1316 struct dm_cache_policy *policy)
1317{
1318 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1319 hints_array_initialized(cmd);
1320}
1321
1322static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1323 uint64_t cb, bool hints_valid,
1324 struct dm_array_cursor *mapping_cursor,
1325 struct dm_array_cursor *hint_cursor,
1326 load_mapping_fn fn, void *context)
1327{
1328 int r = 0;
1329
1330 __le64 mapping;
1331 __le32 hint = 0;
1332
1333 __le64 *mapping_value_le;
1334 __le32 *hint_value_le;
1335
1336 dm_oblock_t oblock;
1337 unsigned int flags;
1338 bool dirty = true;
1339
1340 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1341 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1342 unpack_value(mapping, &oblock, &flags);
1343
1344 if (flags & M_VALID) {
1345 if (hints_valid) {
1346 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1347 memcpy(&hint, hint_value_le, sizeof(hint));
1348 }
1349 if (cmd->clean_when_opened)
1350 dirty = flags & M_DIRTY;
1351
1352 r = fn(context, oblock, to_cblock(cb), dirty,
1353 le32_to_cpu(hint), hints_valid);
1354 if (r) {
1355 DMERR("policy couldn't load cache block %llu",
1356 (unsigned long long) from_cblock(to_cblock(cb)));
1357 }
1358 }
1359
1360 return r;
1361}
1362
1363static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1364 uint64_t cb, bool hints_valid,
1365 struct dm_array_cursor *mapping_cursor,
1366 struct dm_array_cursor *hint_cursor,
1367 struct dm_bitset_cursor *dirty_cursor,
1368 load_mapping_fn fn, void *context)
1369{
1370 int r = 0;
1371
1372 __le64 mapping;
1373 __le32 hint = 0;
1374
1375 __le64 *mapping_value_le;
1376 __le32 *hint_value_le;
1377
1378 dm_oblock_t oblock;
1379 unsigned int flags;
1380 bool dirty = true;
1381
1382 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1383 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1384 unpack_value(mapping, &oblock, &flags);
1385
1386 if (flags & M_VALID) {
1387 if (hints_valid) {
1388 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1389 memcpy(&hint, hint_value_le, sizeof(hint));
1390 }
1391 if (cmd->clean_when_opened)
1392 dirty = dm_bitset_cursor_get_value(dirty_cursor);
1393
1394 r = fn(context, oblock, to_cblock(cb), dirty,
1395 le32_to_cpu(hint), hints_valid);
1396 if (r) {
1397 DMERR("policy couldn't load cache block %llu",
1398 (unsigned long long) from_cblock(to_cblock(cb)));
1399 }
1400 }
1401
1402 return r;
1403}
1404
1405static int __load_mappings(struct dm_cache_metadata *cmd,
1406 struct dm_cache_policy *policy,
1407 load_mapping_fn fn, void *context)
1408{
1409 int r;
1410 uint64_t cb;
1411
1412 bool hints_valid = hints_array_available(cmd, policy);
1413
1414 if (from_cblock(cmd->cache_blocks) == 0)
1415 /* Nothing to do */
1416 return 0;
1417
1418 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1419 if (r)
1420 return r;
1421
1422 if (hints_valid) {
1423 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1424 if (r) {
1425 dm_array_cursor_end(&cmd->mapping_cursor);
1426 return r;
1427 }
1428 }
1429
1430 if (separate_dirty_bits(cmd)) {
1431 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1432 from_cblock(cmd->cache_blocks),
1433 &cmd->dirty_cursor);
1434 if (r) {
1435 dm_array_cursor_end(&cmd->hint_cursor);
1436 dm_array_cursor_end(&cmd->mapping_cursor);
1437 return r;
1438 }
1439 }
1440
1441 for (cb = 0; ; cb++) {
1442 if (separate_dirty_bits(cmd))
1443 r = __load_mapping_v2(cmd, cb, hints_valid,
1444 &cmd->mapping_cursor,
1445 &cmd->hint_cursor,
1446 &cmd->dirty_cursor,
1447 fn, context);
1448 else
1449 r = __load_mapping_v1(cmd, cb, hints_valid,
1450 &cmd->mapping_cursor, &cmd->hint_cursor,
1451 fn, context);
1452 if (r)
1453 goto out;
1454
1455 /*
1456 * We need to break out before we move the cursors.
1457 */
1458 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1459 break;
1460
1461 r = dm_array_cursor_next(&cmd->mapping_cursor);
1462 if (r) {
1463 DMERR("dm_array_cursor_next for mapping failed");
1464 goto out;
1465 }
1466
1467 if (hints_valid) {
1468 r = dm_array_cursor_next(&cmd->hint_cursor);
1469 if (r) {
1470 dm_array_cursor_end(&cmd->hint_cursor);
1471 hints_valid = false;
1472 }
1473 }
1474
1475 if (separate_dirty_bits(cmd)) {
1476 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1477 if (r) {
1478 DMERR("dm_bitset_cursor_next for dirty failed");
1479 goto out;
1480 }
1481 }
1482 }
1483out:
1484 dm_array_cursor_end(&cmd->mapping_cursor);
1485 if (hints_valid)
1486 dm_array_cursor_end(&cmd->hint_cursor);
1487
1488 if (separate_dirty_bits(cmd))
1489 dm_bitset_cursor_end(&cmd->dirty_cursor);
1490
1491 return r;
1492}
1493
1494int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1495 struct dm_cache_policy *policy,
1496 load_mapping_fn fn, void *context)
1497{
1498 int r;
1499
1500 READ_LOCK(cmd);
1501 r = __load_mappings(cmd, policy, fn, context);
1502 READ_UNLOCK(cmd);
1503
1504 return r;
1505}
1506
1507int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1508{
1509 int r;
1510
1511 READ_LOCK(cmd);
1512 r = cmd->changed;
1513 READ_UNLOCK(cmd);
1514
1515 return r;
1516}
1517
1518static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1519{
1520 int r;
1521 unsigned int flags;
1522 dm_oblock_t oblock;
1523 __le64 value;
1524
1525 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1526 if (r)
1527 return r;
1528
1529 unpack_value(value, &oblock, &flags);
1530
1531 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1532 /* nothing to be done */
1533 return 0;
1534
1535 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1536 __dm_bless_for_disk(&value);
1537
1538 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1539 &value, &cmd->root);
1540 if (r)
1541 return r;
1542
1543 cmd->changed = true;
1544 return 0;
1545
1546}
1547
1548static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned int nr_bits, unsigned long *bits)
1549{
1550 int r;
1551 unsigned int i;
1552
1553 for (i = 0; i < nr_bits; i++) {
1554 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1555 if (r)
1556 return r;
1557 }
1558
1559 return 0;
1560}
1561
1562static int is_dirty_callback(uint32_t index, bool *value, void *context)
1563{
1564 unsigned long *bits = context;
1565 *value = test_bit(index, bits);
1566 return 0;
1567}
1568
1569static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned int nr_bits, unsigned long *bits)
1570{
1571 int r = 0;
1572
1573 /* nr_bits is really just a sanity check */
1574 if (nr_bits != from_cblock(cmd->cache_blocks)) {
1575 DMERR("dirty bitset is wrong size");
1576 return -EINVAL;
1577 }
1578
1579 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1580 if (r)
1581 return r;
1582
1583 cmd->changed = true;
1584 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1585}
1586
1587int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1588 unsigned int nr_bits,
1589 unsigned long *bits)
1590{
1591 int r;
1592
1593 WRITE_LOCK(cmd);
1594 if (separate_dirty_bits(cmd))
1595 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1596 else
1597 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1598 WRITE_UNLOCK(cmd);
1599
1600 return r;
1601}
1602
1603void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1604 struct dm_cache_statistics *stats)
1605{
1606 READ_LOCK_VOID(cmd);
1607 *stats = cmd->stats;
1608 READ_UNLOCK(cmd);
1609}
1610
1611void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1612 struct dm_cache_statistics *stats)
1613{
1614 WRITE_LOCK_VOID(cmd);
1615 cmd->stats = *stats;
1616 WRITE_UNLOCK(cmd);
1617}
1618
1619int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1620{
1621 int r = -EINVAL;
1622 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1623 clear_clean_shutdown);
1624
1625 WRITE_LOCK(cmd);
1626 if (cmd->fail_io)
1627 goto out;
1628
1629 r = __commit_transaction(cmd, mutator);
1630 if (r)
1631 goto out;
1632
1633 r = __begin_transaction(cmd);
1634out:
1635 WRITE_UNLOCK(cmd);
1636 return r;
1637}
1638
1639int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1640 dm_block_t *result)
1641{
1642 int r = -EINVAL;
1643
1644 READ_LOCK(cmd);
1645 if (!cmd->fail_io)
1646 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1647 READ_UNLOCK(cmd);
1648
1649 return r;
1650}
1651
1652int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1653 dm_block_t *result)
1654{
1655 int r = -EINVAL;
1656
1657 READ_LOCK(cmd);
1658 if (!cmd->fail_io)
1659 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1660 READ_UNLOCK(cmd);
1661
1662 return r;
1663}
1664
1665/*----------------------------------------------------------------*/
1666
1667static int get_hint(uint32_t index, void *value_le, void *context)
1668{
1669 uint32_t value;
1670 struct dm_cache_policy *policy = context;
1671
1672 value = policy_get_hint(policy, to_cblock(index));
1673 *((__le32 *) value_le) = cpu_to_le32(value);
1674
1675 return 0;
1676}
1677
1678/*
1679 * It's quicker to always delete the hint array, and recreate with
1680 * dm_array_new().
1681 */
1682static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1683{
1684 int r;
1685 size_t hint_size;
1686 const char *policy_name = dm_cache_policy_get_name(policy);
1687 const unsigned int *policy_version = dm_cache_policy_get_version(policy);
1688
1689 if (!policy_name[0] ||
1690 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1691 return -EINVAL;
1692
1693 strscpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1694 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1695
1696 hint_size = dm_cache_policy_get_hint_size(policy);
1697 if (!hint_size)
1698 return 0; /* short-circuit hints initialization */
1699 cmd->policy_hint_size = hint_size;
1700
1701 if (cmd->hint_root) {
1702 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1703 if (r)
1704 return r;
1705 }
1706
1707 return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1708 from_cblock(cmd->cache_blocks),
1709 get_hint, policy);
1710}
1711
1712int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1713{
1714 int r;
1715
1716 WRITE_LOCK(cmd);
1717 r = write_hints(cmd, policy);
1718 WRITE_UNLOCK(cmd);
1719
1720 return r;
1721}
1722
1723void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1724{
1725 WRITE_LOCK_VOID(cmd);
1726 dm_bm_set_read_only(cmd->bm);
1727 WRITE_UNLOCK(cmd);
1728}
1729
1730void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1731{
1732 WRITE_LOCK_VOID(cmd);
1733 dm_bm_set_read_write(cmd->bm);
1734 WRITE_UNLOCK(cmd);
1735}
1736
1737int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1738{
1739 int r;
1740 struct dm_block *sblock;
1741 struct cache_disk_superblock *disk_super;
1742
1743 WRITE_LOCK(cmd);
1744 set_bit(NEEDS_CHECK, &cmd->flags);
1745
1746 r = superblock_lock(cmd, &sblock);
1747 if (r) {
1748 DMERR("couldn't read superblock");
1749 goto out;
1750 }
1751
1752 disk_super = dm_block_data(sblock);
1753 disk_super->flags = cpu_to_le32(cmd->flags);
1754
1755 dm_bm_unlock(sblock);
1756
1757out:
1758 WRITE_UNLOCK(cmd);
1759 return r;
1760}
1761
1762int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1763{
1764 READ_LOCK(cmd);
1765 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1766 READ_UNLOCK(cmd);
1767
1768 return 0;
1769}
1770
1771int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1772{
1773 int r = -EINVAL;
1774 struct dm_block_manager *old_bm = NULL, *new_bm = NULL;
1775
1776 /* fail_io is double-checked with cmd->root_lock held below */
1777 if (unlikely(cmd->fail_io))
1778 return r;
1779
1780 /*
1781 * Replacement block manager (new_bm) is created and old_bm destroyed outside of
1782 * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
1783 * shrinker associated with the block manager's bufio client vs cmd root_lock).
1784 * - must take shrinker_mutex without holding cmd->root_lock
1785 */
1786 new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
1787 CACHE_MAX_CONCURRENT_LOCKS);
1788
1789 /* cmd_write_lock() already checks fail_io with cmd->root_lock held */
1790 WRITE_LOCK_OR_GOTO(cmd, out);
1791
1792 __destroy_persistent_data_objects(cmd, false);
1793 old_bm = cmd->bm;
1794 if (IS_ERR(new_bm)) {
1795 DMERR("could not create block manager during abort");
1796 cmd->bm = NULL;
1797 r = PTR_ERR(new_bm);
1798 goto out_unlock;
1799 }
1800
1801 cmd->bm = new_bm;
1802 r = __open_or_format_metadata(cmd, false);
1803 if (r) {
1804 cmd->bm = NULL;
1805 goto out_unlock;
1806 }
1807 new_bm = NULL;
1808out_unlock:
1809 if (r)
1810 cmd->fail_io = true;
1811 WRITE_UNLOCK(cmd);
1812 dm_block_manager_destroy(old_bm);
1813out:
1814 if (new_bm && !IS_ERR(new_bm))
1815 dm_block_manager_destroy(new_bm);
1816
1817 return r;
1818}
1819
1820int dm_cache_metadata_clean_when_opened(struct dm_cache_metadata *cmd, bool *result)
1821{
1822 READ_LOCK(cmd);
1823 *result = cmd->clean_when_opened;
1824 READ_UNLOCK(cmd);
1825
1826 return 0;
1827}