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(bm: cmd->bm, CACHE_SUPERBLOCK_LOCATION,
243 v: &sb_validator, result: 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(bm: cmd->bm, CACHE_SUPERBLOCK_LOCATION,
250 v: &sb_validator, result: sblock);
251}
252
253static int superblock_lock(struct dm_cache_metadata *cmd,
254 struct dm_block **sblock)
255{
256 return dm_bm_write_lock(bm: cmd->bm, CACHE_SUPERBLOCK_LOCATION,
257 v: &sb_validator, result: 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, result: &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(info: &cmd->info, tm: cmd->tm, vt: &vt);
301
302 if (cmd->policy_hint_size) {
303 vt.size = sizeof(__le32);
304 dm_array_info_init(info: &cmd->hint_info, tm: cmd->tm, vt: &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(sm: cmd->metadata_sm, result: &metadata_len);
314 if (r < 0)
315 return r;
316
317 return dm_sm_copy_root(sm: cmd->metadata_sm, copy_to_here_le: &cmd->metadata_space_map_root,
318 len: 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(bdev: 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(tm: 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: &sblock);
358 if (r)
359 return r;
360
361 disk_super = dm_block_data(b: 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(tm: cmd->tm, superblock: sblock);
390}
391
392static int __format_metadata(struct dm_cache_metadata *cmd)
393{
394 int r;
395
396 r = dm_tm_create_with_sm(bm: cmd->bm, CACHE_SUPERBLOCK_LOCATION,
397 tm: &cmd->tm, sm: &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(info: &cmd->info, root: &cmd->root);
406 if (r < 0)
407 goto bad;
408
409 if (separate_dirty_bits(cmd)) {
410 dm_disk_bitset_init(tm: cmd->tm, info: &cmd->dirty_info);
411 r = dm_bitset_empty(info: &cmd->dirty_info, new_root: &cmd->dirty_root);
412 if (r < 0)
413 goto bad;
414 }
415
416 dm_disk_bitset_init(tm: cmd->tm, info: &cmd->discard_info);
417 r = dm_bitset_empty(info: &cmd->discard_info, new_root: &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(tm: cmd->tm);
433 dm_sm_destroy(sm: 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(bdev: 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: &sblock);
475 if (r < 0) {
476 DMERR("couldn't read lock superblock");
477 return r;
478 }
479
480 disk_super = dm_block_data(b: 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(bm: cmd->bm, CACHE_SUPERBLOCK_LOCATION,
496 sm_root: disk_super->metadata_space_map_root,
497 root_len: sizeof(disk_super->metadata_space_map_root),
498 tm: &cmd->tm, sm: &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(tm: cmd->tm, info: &cmd->dirty_info);
506 dm_disk_bitset_init(tm: cmd->tm, info: &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(b: sblock);
510
511 return 0;
512
513bad:
514 dm_bm_unlock(b: 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(bm: cmd->bm, result: &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(bdev: cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
540 CACHE_MAX_CONCURRENT_LOCKS);
541 if (IS_ERR(ptr: cmd->bm)) {
542 DMERR("could not create block manager");
543 r = PTR_ERR(ptr: cmd->bm);
544 cmd->bm = NULL;
545 return r;
546 }
547
548 r = __open_or_format_metadata(cmd, format_device: may_format_device);
549 if (r) {
550 dm_block_manager_destroy(bm: 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(sm: cmd->metadata_sm);
561 dm_tm_destroy(tm: cmd->tm);
562 if (destroy_bm)
563 dm_block_manager_destroy(bm: 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(nr: CLEAN_SHUTDOWN, addr: &flags);
579 return flags;
580}
581
582static unsigned long clear_clean_shutdown(unsigned long flags)
583{
584 clear_bit(nr: CLEAN_SHUTDOWN, addr: &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: &sblock);
628 if (r)
629 return r;
630
631 disk_super = dm_block_data(b: sblock);
632 update_flags(disk_super, mutator);
633 read_superblock_fields(cmd, disk_super);
634 dm_bm_unlock(b: sblock);
635
636 return dm_bm_flush(bm: 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: &sblock);
650 if (r)
651 return r;
652
653 disk_super = dm_block_data(b: sblock);
654 read_superblock_fields(cmd, disk_super);
655 dm_bm_unlock(b: 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(info: &cmd->dirty_info, root: cmd->dirty_root,
674 new_root: &cmd->dirty_root);
675 if (r)
676 return r;
677 }
678
679 r = dm_bitset_flush(info: &cmd->discard_info, root: cmd->discard_root,
680 new_root: &cmd->discard_root);
681 if (r)
682 return r;
683
684 r = dm_tm_pre_commit(tm: 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: &sblock);
693 if (r)
694 return r;
695
696 disk_super = dm_block_data(b: 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(tm: cmd->tm, superblock: 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(b: 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(sizeof(*cmd), GFP_KERNEL);
764 if (!cmd) {
765 DMERR("could not allocate metadata struct");
766 return ERR_PTR(error: -ENOMEM);
767 }
768
769 cmd->version = metadata_version;
770 refcount_set(r: &cmd->ref_count, n: 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(objp: cmd);
782 return ERR_PTR(error: r);
783 }
784
785 r = __begin_transaction_flags(cmd, mutator: clear_clean_shutdown);
786 if (r < 0) {
787 dm_cache_metadata_close(cmd);
788 return ERR_PTR(error: 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(r: &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(lock: &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(ptr: cmd)) {
833 mutex_lock(&table_lock);
834 cmd2 = lookup(bdev);
835 if (cmd2) {
836 mutex_unlock(lock: &table_lock);
837 __destroy_persistent_data_objects(cmd, destroy_bm: true);
838 kfree(objp: cmd);
839 return cmd2;
840 }
841 list_add(new: &cmd->list, head: &table);
842 mutex_unlock(lock: &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(ptr: cmd) && !same_params(cmd, data_block_size)) {
870 dm_cache_metadata_close(cmd);
871 return ERR_PTR(error: -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(r: &cmd->ref_count)) {
880 mutex_lock(&table_lock);
881 list_del(entry: &cmd->list);
882 mutex_unlock(lock: &table_lock);
883
884 if (!cmd->fail_io)
885 __destroy_persistent_data_objects(cmd, destroy_bm: true);
886 kfree(objp: 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(info: &cmd->info, root: cmd->root, index: from_cblock(b), value: &value);
902 if (r)
903 return r;
904
905 unpack_value(value_le: value, block: &ob, flags: &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, b: 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(b: from_cblock(b: 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(b: cmd->cache_blocks) == 0)
946 /* Nothing to do */
947 return 0;
948
949 r = dm_bitset_cursor_begin(info: &cmd->dirty_info, root: cmd->dirty_root,
950 nr_entries: from_cblock(b: cmd->cache_blocks), c: &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(c: &cmd->dirty_cursor, count: from_cblock(b: begin));
957 if (r) {
958 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
959 dm_bitset_cursor_end(c: &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(c: &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(c: &cmd->dirty_cursor);
973 *result = false;
974 return 0;
975 }
976
977 begin = to_cblock(b: from_cblock(b: begin) + 1);
978 if (begin == end)
979 break;
980
981 r = dm_bitset_cursor_next(c: &cmd->dirty_cursor);
982 if (r) {
983 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
984 dm_bitset_cursor_end(c: &cmd->dirty_cursor);
985 return r;
986 }
987 }
988
989 dm_bitset_cursor_end(c: &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(sem: &cmd->root_lock);
1007 if (cmd->fail_io || dm_bm_is_read_only(bm: cmd->bm)) {
1008 up_write(sem: &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_UNLOCK(cmd) \
1027 up_write(&(cmd)->root_lock)
1028
1029static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1030{
1031 down_read(sem: &cmd->root_lock);
1032 if (cmd->fail_io) {
1033 up_read(sem: &cmd->root_lock);
1034 return false;
1035 }
1036 return true;
1037}
1038
1039#define READ_LOCK(cmd) \
1040 do { \
1041 if (!cmd_read_lock((cmd))) \
1042 return -EINVAL; \
1043 } while (0)
1044
1045#define READ_LOCK_VOID(cmd) \
1046 do { \
1047 if (!cmd_read_lock((cmd))) \
1048 return; \
1049 } while (0)
1050
1051#define READ_UNLOCK(cmd) \
1052 up_read(&(cmd)->root_lock)
1053
1054int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1055{
1056 int r;
1057 bool clean;
1058 __le64 null_mapping = pack_value(block: 0, flags: 0);
1059
1060 WRITE_LOCK(cmd);
1061 __dm_bless_for_disk(&null_mapping);
1062
1063 if (from_cblock(b: new_cache_size) < from_cblock(b: cmd->cache_blocks)) {
1064 r = blocks_are_unmapped_or_clean(cmd, begin: new_cache_size, end: cmd->cache_blocks, result: &clean);
1065 if (r) {
1066 __dm_unbless_for_disk(&null_mapping);
1067 goto out;
1068 }
1069
1070 if (!clean) {
1071 DMERR("unable to shrink cache due to dirty blocks");
1072 r = -EINVAL;
1073 __dm_unbless_for_disk(&null_mapping);
1074 goto out;
1075 }
1076 }
1077
1078 r = dm_array_resize(info: &cmd->info, root: cmd->root, old_size: from_cblock(b: cmd->cache_blocks),
1079 new_size: from_cblock(b: new_cache_size),
1080 value: &null_mapping, new_root: &cmd->root);
1081 if (r)
1082 goto out;
1083
1084 if (separate_dirty_bits(cmd)) {
1085 r = dm_bitset_resize(info: &cmd->dirty_info, old_root: cmd->dirty_root,
1086 old_nr_entries: from_cblock(b: cmd->cache_blocks), new_nr_entries: from_cblock(b: new_cache_size),
1087 default_value: false, new_root: &cmd->dirty_root);
1088 if (r)
1089 goto out;
1090 }
1091
1092 cmd->cache_blocks = new_cache_size;
1093 cmd->changed = true;
1094
1095out:
1096 WRITE_UNLOCK(cmd);
1097
1098 return r;
1099}
1100
1101int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1102 sector_t discard_block_size,
1103 dm_dblock_t new_nr_entries)
1104{
1105 int r;
1106
1107 WRITE_LOCK(cmd);
1108 r = dm_bitset_resize(info: &cmd->discard_info,
1109 old_root: cmd->discard_root,
1110 old_nr_entries: from_dblock(b: cmd->discard_nr_blocks),
1111 new_nr_entries: from_dblock(b: new_nr_entries),
1112 default_value: false, new_root: &cmd->discard_root);
1113 if (!r) {
1114 cmd->discard_block_size = discard_block_size;
1115 cmd->discard_nr_blocks = new_nr_entries;
1116 }
1117
1118 cmd->changed = true;
1119 WRITE_UNLOCK(cmd);
1120
1121 return r;
1122}
1123
1124static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1125{
1126 return dm_bitset_set_bit(info: &cmd->discard_info, root: cmd->discard_root,
1127 index: from_dblock(b), new_root: &cmd->discard_root);
1128}
1129
1130static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1131{
1132 return dm_bitset_clear_bit(info: &cmd->discard_info, root: cmd->discard_root,
1133 index: from_dblock(b), new_root: &cmd->discard_root);
1134}
1135
1136static int __discard(struct dm_cache_metadata *cmd,
1137 dm_dblock_t dblock, bool discard)
1138{
1139 int r;
1140
1141 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1142 if (r)
1143 return r;
1144
1145 cmd->changed = true;
1146 return 0;
1147}
1148
1149int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1150 dm_dblock_t dblock, bool discard)
1151{
1152 int r;
1153
1154 WRITE_LOCK(cmd);
1155 r = __discard(cmd, dblock, discard);
1156 WRITE_UNLOCK(cmd);
1157
1158 return r;
1159}
1160
1161static int __load_discards(struct dm_cache_metadata *cmd,
1162 load_discard_fn fn, void *context)
1163{
1164 int r = 0;
1165 uint32_t b;
1166 struct dm_bitset_cursor c;
1167
1168 if (from_dblock(b: cmd->discard_nr_blocks) == 0)
1169 /* nothing to do */
1170 return 0;
1171
1172 if (cmd->clean_when_opened) {
1173 r = dm_bitset_flush(info: &cmd->discard_info, root: cmd->discard_root, new_root: &cmd->discard_root);
1174 if (r)
1175 return r;
1176
1177 r = dm_bitset_cursor_begin(info: &cmd->discard_info, root: cmd->discard_root,
1178 nr_entries: from_dblock(b: cmd->discard_nr_blocks), c: &c);
1179 if (r)
1180 return r;
1181
1182 for (b = 0; ; b++) {
1183 r = fn(context, cmd->discard_block_size, to_dblock(b),
1184 dm_bitset_cursor_get_value(c: &c));
1185 if (r)
1186 break;
1187
1188 if (b >= (from_dblock(b: cmd->discard_nr_blocks) - 1))
1189 break;
1190
1191 r = dm_bitset_cursor_next(c: &c);
1192 if (r)
1193 break;
1194 }
1195
1196 dm_bitset_cursor_end(c: &c);
1197
1198 } else {
1199 for (b = 0; b < from_dblock(b: cmd->discard_nr_blocks); b++) {
1200 r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1201 if (r)
1202 return r;
1203 }
1204 }
1205
1206 return r;
1207}
1208
1209int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1210 load_discard_fn fn, void *context)
1211{
1212 int r;
1213
1214 READ_LOCK(cmd);
1215 r = __load_discards(cmd, fn, context);
1216 READ_UNLOCK(cmd);
1217
1218 return r;
1219}
1220
1221static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1222{
1223 int r;
1224 __le64 value = pack_value(block: 0, flags: 0);
1225
1226 __dm_bless_for_disk(&value);
1227 r = dm_array_set_value(info: &cmd->info, root: cmd->root, index: from_cblock(b: cblock),
1228 value: &value, new_root: &cmd->root);
1229 if (r)
1230 return r;
1231
1232 cmd->changed = true;
1233 return 0;
1234}
1235
1236int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1237{
1238 int r;
1239
1240 WRITE_LOCK(cmd);
1241 r = __remove(cmd, cblock);
1242 WRITE_UNLOCK(cmd);
1243
1244 return r;
1245}
1246
1247static int __insert(struct dm_cache_metadata *cmd,
1248 dm_cblock_t cblock, dm_oblock_t oblock)
1249{
1250 int r;
1251 __le64 value = pack_value(block: oblock, flags: M_VALID);
1252
1253 __dm_bless_for_disk(&value);
1254
1255 r = dm_array_set_value(info: &cmd->info, root: cmd->root, index: from_cblock(b: cblock),
1256 value: &value, new_root: &cmd->root);
1257 if (r)
1258 return r;
1259
1260 cmd->changed = true;
1261 return 0;
1262}
1263
1264int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1265 dm_cblock_t cblock, dm_oblock_t oblock)
1266{
1267 int r;
1268
1269 WRITE_LOCK(cmd);
1270 r = __insert(cmd, cblock, oblock);
1271 WRITE_UNLOCK(cmd);
1272
1273 return r;
1274}
1275
1276static bool policy_unchanged(struct dm_cache_metadata *cmd,
1277 struct dm_cache_policy *policy)
1278{
1279 const char *policy_name = dm_cache_policy_get_name(p: policy);
1280 const unsigned int *policy_version = dm_cache_policy_get_version(p: policy);
1281 size_t policy_hint_size = dm_cache_policy_get_hint_size(p: policy);
1282
1283 /*
1284 * Ensure policy names match.
1285 */
1286 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1287 return false;
1288
1289 /*
1290 * Ensure policy major versions match.
1291 */
1292 if (cmd->policy_version[0] != policy_version[0])
1293 return false;
1294
1295 /*
1296 * Ensure policy hint sizes match.
1297 */
1298 if (cmd->policy_hint_size != policy_hint_size)
1299 return false;
1300
1301 return true;
1302}
1303
1304static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1305{
1306 return cmd->hint_root && cmd->policy_hint_size;
1307}
1308
1309static bool hints_array_available(struct dm_cache_metadata *cmd,
1310 struct dm_cache_policy *policy)
1311{
1312 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1313 hints_array_initialized(cmd);
1314}
1315
1316static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1317 uint64_t cb, bool hints_valid,
1318 struct dm_array_cursor *mapping_cursor,
1319 struct dm_array_cursor *hint_cursor,
1320 load_mapping_fn fn, void *context)
1321{
1322 int r = 0;
1323
1324 __le64 mapping;
1325 __le32 hint = 0;
1326
1327 __le64 *mapping_value_le;
1328 __le32 *hint_value_le;
1329
1330 dm_oblock_t oblock;
1331 unsigned int flags;
1332 bool dirty = true;
1333
1334 dm_array_cursor_get_value(c: mapping_cursor, value_le: (void **) &mapping_value_le);
1335 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1336 unpack_value(value_le: mapping, block: &oblock, flags: &flags);
1337
1338 if (flags & M_VALID) {
1339 if (hints_valid) {
1340 dm_array_cursor_get_value(c: hint_cursor, value_le: (void **) &hint_value_le);
1341 memcpy(&hint, hint_value_le, sizeof(hint));
1342 }
1343 if (cmd->clean_when_opened)
1344 dirty = flags & M_DIRTY;
1345
1346 r = fn(context, oblock, to_cblock(b: cb), dirty,
1347 le32_to_cpu(hint), hints_valid);
1348 if (r) {
1349 DMERR("policy couldn't load cache block %llu",
1350 (unsigned long long) from_cblock(to_cblock(cb)));
1351 }
1352 }
1353
1354 return r;
1355}
1356
1357static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1358 uint64_t cb, bool hints_valid,
1359 struct dm_array_cursor *mapping_cursor,
1360 struct dm_array_cursor *hint_cursor,
1361 struct dm_bitset_cursor *dirty_cursor,
1362 load_mapping_fn fn, void *context)
1363{
1364 int r = 0;
1365
1366 __le64 mapping;
1367 __le32 hint = 0;
1368
1369 __le64 *mapping_value_le;
1370 __le32 *hint_value_le;
1371
1372 dm_oblock_t oblock;
1373 unsigned int flags;
1374 bool dirty = true;
1375
1376 dm_array_cursor_get_value(c: mapping_cursor, value_le: (void **) &mapping_value_le);
1377 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1378 unpack_value(value_le: mapping, block: &oblock, flags: &flags);
1379
1380 if (flags & M_VALID) {
1381 if (hints_valid) {
1382 dm_array_cursor_get_value(c: hint_cursor, value_le: (void **) &hint_value_le);
1383 memcpy(&hint, hint_value_le, sizeof(hint));
1384 }
1385 if (cmd->clean_when_opened)
1386 dirty = dm_bitset_cursor_get_value(c: dirty_cursor);
1387
1388 r = fn(context, oblock, to_cblock(b: cb), dirty,
1389 le32_to_cpu(hint), hints_valid);
1390 if (r) {
1391 DMERR("policy couldn't load cache block %llu",
1392 (unsigned long long) from_cblock(to_cblock(cb)));
1393 }
1394 }
1395
1396 return r;
1397}
1398
1399static int __load_mappings(struct dm_cache_metadata *cmd,
1400 struct dm_cache_policy *policy,
1401 load_mapping_fn fn, void *context)
1402{
1403 int r;
1404 uint64_t cb;
1405
1406 bool hints_valid = hints_array_available(cmd, policy);
1407
1408 if (from_cblock(b: cmd->cache_blocks) == 0)
1409 /* Nothing to do */
1410 return 0;
1411
1412 r = dm_array_cursor_begin(info: &cmd->info, root: cmd->root, c: &cmd->mapping_cursor);
1413 if (r)
1414 return r;
1415
1416 if (hints_valid) {
1417 r = dm_array_cursor_begin(info: &cmd->hint_info, root: cmd->hint_root, c: &cmd->hint_cursor);
1418 if (r) {
1419 dm_array_cursor_end(c: &cmd->mapping_cursor);
1420 return r;
1421 }
1422 }
1423
1424 if (separate_dirty_bits(cmd)) {
1425 r = dm_bitset_cursor_begin(info: &cmd->dirty_info, root: cmd->dirty_root,
1426 nr_entries: from_cblock(b: cmd->cache_blocks),
1427 c: &cmd->dirty_cursor);
1428 if (r) {
1429 dm_array_cursor_end(c: &cmd->hint_cursor);
1430 dm_array_cursor_end(c: &cmd->mapping_cursor);
1431 return r;
1432 }
1433 }
1434
1435 for (cb = 0; ; cb++) {
1436 if (separate_dirty_bits(cmd))
1437 r = __load_mapping_v2(cmd, cb, hints_valid,
1438 mapping_cursor: &cmd->mapping_cursor,
1439 hint_cursor: &cmd->hint_cursor,
1440 dirty_cursor: &cmd->dirty_cursor,
1441 fn, context);
1442 else
1443 r = __load_mapping_v1(cmd, cb, hints_valid,
1444 mapping_cursor: &cmd->mapping_cursor, hint_cursor: &cmd->hint_cursor,
1445 fn, context);
1446 if (r)
1447 goto out;
1448
1449 /*
1450 * We need to break out before we move the cursors.
1451 */
1452 if (cb >= (from_cblock(b: cmd->cache_blocks) - 1))
1453 break;
1454
1455 r = dm_array_cursor_next(c: &cmd->mapping_cursor);
1456 if (r) {
1457 DMERR("dm_array_cursor_next for mapping failed");
1458 goto out;
1459 }
1460
1461 if (hints_valid) {
1462 r = dm_array_cursor_next(c: &cmd->hint_cursor);
1463 if (r) {
1464 dm_array_cursor_end(c: &cmd->hint_cursor);
1465 hints_valid = false;
1466 }
1467 }
1468
1469 if (separate_dirty_bits(cmd)) {
1470 r = dm_bitset_cursor_next(c: &cmd->dirty_cursor);
1471 if (r) {
1472 DMERR("dm_bitset_cursor_next for dirty failed");
1473 goto out;
1474 }
1475 }
1476 }
1477out:
1478 dm_array_cursor_end(c: &cmd->mapping_cursor);
1479 if (hints_valid)
1480 dm_array_cursor_end(c: &cmd->hint_cursor);
1481
1482 if (separate_dirty_bits(cmd))
1483 dm_bitset_cursor_end(c: &cmd->dirty_cursor);
1484
1485 return r;
1486}
1487
1488int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1489 struct dm_cache_policy *policy,
1490 load_mapping_fn fn, void *context)
1491{
1492 int r;
1493
1494 READ_LOCK(cmd);
1495 r = __load_mappings(cmd, policy, fn, context);
1496 READ_UNLOCK(cmd);
1497
1498 return r;
1499}
1500
1501int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1502{
1503 int r;
1504
1505 READ_LOCK(cmd);
1506 r = cmd->changed;
1507 READ_UNLOCK(cmd);
1508
1509 return r;
1510}
1511
1512static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1513{
1514 int r;
1515 unsigned int flags;
1516 dm_oblock_t oblock;
1517 __le64 value;
1518
1519 r = dm_array_get_value(info: &cmd->info, root: cmd->root, index: from_cblock(b: cblock), value: &value);
1520 if (r)
1521 return r;
1522
1523 unpack_value(value_le: value, block: &oblock, flags: &flags);
1524
1525 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1526 /* nothing to be done */
1527 return 0;
1528
1529 value = pack_value(block: oblock, flags: (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1530 __dm_bless_for_disk(&value);
1531
1532 r = dm_array_set_value(info: &cmd->info, root: cmd->root, index: from_cblock(b: cblock),
1533 value: &value, new_root: &cmd->root);
1534 if (r)
1535 return r;
1536
1537 cmd->changed = true;
1538 return 0;
1539
1540}
1541
1542static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned int nr_bits, unsigned long *bits)
1543{
1544 int r;
1545 unsigned int i;
1546
1547 for (i = 0; i < nr_bits; i++) {
1548 r = __dirty(cmd, cblock: to_cblock(b: i), test_bit(i, bits));
1549 if (r)
1550 return r;
1551 }
1552
1553 return 0;
1554}
1555
1556static int is_dirty_callback(uint32_t index, bool *value, void *context)
1557{
1558 unsigned long *bits = context;
1559 *value = test_bit(index, bits);
1560 return 0;
1561}
1562
1563static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned int nr_bits, unsigned long *bits)
1564{
1565 int r = 0;
1566
1567 /* nr_bits is really just a sanity check */
1568 if (nr_bits != from_cblock(b: cmd->cache_blocks)) {
1569 DMERR("dirty bitset is wrong size");
1570 return -EINVAL;
1571 }
1572
1573 r = dm_bitset_del(info: &cmd->dirty_info, root: cmd->dirty_root);
1574 if (r)
1575 return r;
1576
1577 cmd->changed = true;
1578 return dm_bitset_new(info: &cmd->dirty_info, root: &cmd->dirty_root, size: nr_bits, fn: is_dirty_callback, context: bits);
1579}
1580
1581int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1582 unsigned int nr_bits,
1583 unsigned long *bits)
1584{
1585 int r;
1586
1587 WRITE_LOCK(cmd);
1588 if (separate_dirty_bits(cmd))
1589 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1590 else
1591 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1592 WRITE_UNLOCK(cmd);
1593
1594 return r;
1595}
1596
1597void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1598 struct dm_cache_statistics *stats)
1599{
1600 READ_LOCK_VOID(cmd);
1601 *stats = cmd->stats;
1602 READ_UNLOCK(cmd);
1603}
1604
1605void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1606 struct dm_cache_statistics *stats)
1607{
1608 WRITE_LOCK_VOID(cmd);
1609 cmd->stats = *stats;
1610 WRITE_UNLOCK(cmd);
1611}
1612
1613int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1614{
1615 int r = -EINVAL;
1616 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1617 clear_clean_shutdown);
1618
1619 WRITE_LOCK(cmd);
1620 if (cmd->fail_io)
1621 goto out;
1622
1623 r = __commit_transaction(cmd, mutator);
1624 if (r)
1625 goto out;
1626
1627 r = __begin_transaction(cmd);
1628out:
1629 WRITE_UNLOCK(cmd);
1630 return r;
1631}
1632
1633int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1634 dm_block_t *result)
1635{
1636 int r = -EINVAL;
1637
1638 READ_LOCK(cmd);
1639 if (!cmd->fail_io)
1640 r = dm_sm_get_nr_free(sm: cmd->metadata_sm, count: result);
1641 READ_UNLOCK(cmd);
1642
1643 return r;
1644}
1645
1646int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1647 dm_block_t *result)
1648{
1649 int r = -EINVAL;
1650
1651 READ_LOCK(cmd);
1652 if (!cmd->fail_io)
1653 r = dm_sm_get_nr_blocks(sm: cmd->metadata_sm, count: result);
1654 READ_UNLOCK(cmd);
1655
1656 return r;
1657}
1658
1659/*----------------------------------------------------------------*/
1660
1661static int get_hint(uint32_t index, void *value_le, void *context)
1662{
1663 uint32_t value;
1664 struct dm_cache_policy *policy = context;
1665
1666 value = policy_get_hint(p: policy, cblock: to_cblock(b: index));
1667 *((__le32 *) value_le) = cpu_to_le32(value);
1668
1669 return 0;
1670}
1671
1672/*
1673 * It's quicker to always delete the hint array, and recreate with
1674 * dm_array_new().
1675 */
1676static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1677{
1678 int r;
1679 size_t hint_size;
1680 const char *policy_name = dm_cache_policy_get_name(p: policy);
1681 const unsigned int *policy_version = dm_cache_policy_get_version(p: policy);
1682
1683 if (!policy_name[0] ||
1684 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1685 return -EINVAL;
1686
1687 strscpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1688 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1689
1690 hint_size = dm_cache_policy_get_hint_size(p: policy);
1691 if (!hint_size)
1692 return 0; /* short-circuit hints initialization */
1693 cmd->policy_hint_size = hint_size;
1694
1695 if (cmd->hint_root) {
1696 r = dm_array_del(info: &cmd->hint_info, root: cmd->hint_root);
1697 if (r)
1698 return r;
1699 }
1700
1701 return dm_array_new(info: &cmd->hint_info, root: &cmd->hint_root,
1702 size: from_cblock(b: cmd->cache_blocks),
1703 fn: get_hint, context: policy);
1704}
1705
1706int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1707{
1708 int r;
1709
1710 WRITE_LOCK(cmd);
1711 r = write_hints(cmd, policy);
1712 WRITE_UNLOCK(cmd);
1713
1714 return r;
1715}
1716
1717int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1718{
1719 int r;
1720
1721 READ_LOCK(cmd);
1722 r = blocks_are_unmapped_or_clean(cmd, begin: 0, end: cmd->cache_blocks, result);
1723 READ_UNLOCK(cmd);
1724
1725 return r;
1726}
1727
1728void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1729{
1730 WRITE_LOCK_VOID(cmd);
1731 dm_bm_set_read_only(bm: cmd->bm);
1732 WRITE_UNLOCK(cmd);
1733}
1734
1735void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1736{
1737 WRITE_LOCK_VOID(cmd);
1738 dm_bm_set_read_write(bm: cmd->bm);
1739 WRITE_UNLOCK(cmd);
1740}
1741
1742int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1743{
1744 int r;
1745 struct dm_block *sblock;
1746 struct cache_disk_superblock *disk_super;
1747
1748 WRITE_LOCK(cmd);
1749 set_bit(nr: NEEDS_CHECK, addr: &cmd->flags);
1750
1751 r = superblock_lock(cmd, sblock: &sblock);
1752 if (r) {
1753 DMERR("couldn't read superblock");
1754 goto out;
1755 }
1756
1757 disk_super = dm_block_data(b: sblock);
1758 disk_super->flags = cpu_to_le32(cmd->flags);
1759
1760 dm_bm_unlock(b: sblock);
1761
1762out:
1763 WRITE_UNLOCK(cmd);
1764 return r;
1765}
1766
1767int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1768{
1769 READ_LOCK(cmd);
1770 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1771 READ_UNLOCK(cmd);
1772
1773 return 0;
1774}
1775
1776int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1777{
1778 int r = -EINVAL;
1779 struct dm_block_manager *old_bm = NULL, *new_bm = NULL;
1780
1781 /* fail_io is double-checked with cmd->root_lock held below */
1782 if (unlikely(cmd->fail_io))
1783 return r;
1784
1785 /*
1786 * Replacement block manager (new_bm) is created and old_bm destroyed outside of
1787 * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
1788 * shrinker associated with the block manager's bufio client vs cmd root_lock).
1789 * - must take shrinker_mutex without holding cmd->root_lock
1790 */
1791 new_bm = dm_block_manager_create(bdev: cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
1792 CACHE_MAX_CONCURRENT_LOCKS);
1793
1794 WRITE_LOCK(cmd);
1795 if (cmd->fail_io) {
1796 WRITE_UNLOCK(cmd);
1797 goto out;
1798 }
1799
1800 __destroy_persistent_data_objects(cmd, destroy_bm: false);
1801 old_bm = cmd->bm;
1802 if (IS_ERR(ptr: new_bm)) {
1803 DMERR("could not create block manager during abort");
1804 cmd->bm = NULL;
1805 r = PTR_ERR(ptr: new_bm);
1806 goto out_unlock;
1807 }
1808
1809 cmd->bm = new_bm;
1810 r = __open_or_format_metadata(cmd, format_device: false);
1811 if (r) {
1812 cmd->bm = NULL;
1813 goto out_unlock;
1814 }
1815 new_bm = NULL;
1816out_unlock:
1817 if (r)
1818 cmd->fail_io = true;
1819 WRITE_UNLOCK(cmd);
1820 dm_block_manager_destroy(bm: old_bm);
1821out:
1822 if (new_bm && !IS_ERR(ptr: new_bm))
1823 dm_block_manager_destroy(bm: new_bm);
1824
1825 return r;
1826}
1827

source code of linux/drivers/md/dm-cache-metadata.c