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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(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(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 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(sizeof(*cmd), GFP_KERNEL);
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_UNLOCK(cmd) \
1027 up_write(&(cmd)->root_lock)
1028
1029static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1030{
1031 down_read(&cmd->root_lock);
1032 if (cmd->fail_io) {
1033 up_read(&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(0, 0);
1059
1060 WRITE_LOCK(cmd);
1061 __dm_bless_for_disk(&null_mapping);
1062
1063 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1064 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &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(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1079 from_cblock(new_cache_size),
1080 &null_mapping, &cmd->root);
1081 if (r)
1082 goto out;
1083
1084 if (separate_dirty_bits(cmd)) {
1085 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1086 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1087 false, &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(&cmd->discard_info,
1109 cmd->discard_root,
1110 from_dblock(cmd->discard_nr_blocks),
1111 from_dblock(new_nr_entries),
1112 false, &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(&cmd->discard_info, cmd->discard_root,
1127 from_dblock(b), &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(&cmd->discard_info, cmd->discard_root,
1133 from_dblock(b), &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(cmd->discard_nr_blocks) == 0)
1169 /* nothing to do */
1170 return 0;
1171
1172 if (cmd->clean_when_opened) {
1173 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1174 if (r)
1175 return r;
1176
1177 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1178 from_dblock(cmd->discard_nr_blocks), &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));
1185 if (r)
1186 break;
1187
1188 if (b >= (from_dblock(cmd->discard_nr_blocks) - 1))
1189 break;
1190
1191 r = dm_bitset_cursor_next(&c);
1192 if (r)
1193 break;
1194 }
1195
1196 dm_bitset_cursor_end(&c);
1197
1198 } else {
1199 for (b = 0; b < from_dblock(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
1221int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1222{
1223 READ_LOCK(cmd);
1224 *result = cmd->cache_blocks;
1225 READ_UNLOCK(cmd);
1226
1227 return 0;
1228}
1229
1230static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1231{
1232 int r;
1233 __le64 value = pack_value(0, 0);
1234
1235 __dm_bless_for_disk(&value);
1236 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1237 &value, &cmd->root);
1238 if (r)
1239 return r;
1240
1241 cmd->changed = true;
1242 return 0;
1243}
1244
1245int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1246{
1247 int r;
1248
1249 WRITE_LOCK(cmd);
1250 r = __remove(cmd, cblock);
1251 WRITE_UNLOCK(cmd);
1252
1253 return r;
1254}
1255
1256static int __insert(struct dm_cache_metadata *cmd,
1257 dm_cblock_t cblock, dm_oblock_t oblock)
1258{
1259 int r;
1260 __le64 value = pack_value(oblock, M_VALID);
1261
1262 __dm_bless_for_disk(&value);
1263
1264 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1265 &value, &cmd->root);
1266 if (r)
1267 return r;
1268
1269 cmd->changed = true;
1270 return 0;
1271}
1272
1273int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1274 dm_cblock_t cblock, dm_oblock_t oblock)
1275{
1276 int r;
1277
1278 WRITE_LOCK(cmd);
1279 r = __insert(cmd, cblock, oblock);
1280 WRITE_UNLOCK(cmd);
1281
1282 return r;
1283}
1284
1285struct thunk {
1286 load_mapping_fn fn;
1287 void *context;
1288
1289 struct dm_cache_metadata *cmd;
1290 bool respect_dirty_flags;
1291 bool hints_valid;
1292};
1293
1294static bool policy_unchanged(struct dm_cache_metadata *cmd,
1295 struct dm_cache_policy *policy)
1296{
1297 const char *policy_name = dm_cache_policy_get_name(policy);
1298 const unsigned int *policy_version = dm_cache_policy_get_version(policy);
1299 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1300
1301 /*
1302 * Ensure policy names match.
1303 */
1304 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1305 return false;
1306
1307 /*
1308 * Ensure policy major versions match.
1309 */
1310 if (cmd->policy_version[0] != policy_version[0])
1311 return false;
1312
1313 /*
1314 * Ensure policy hint sizes match.
1315 */
1316 if (cmd->policy_hint_size != policy_hint_size)
1317 return false;
1318
1319 return true;
1320}
1321
1322static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1323{
1324 return cmd->hint_root && cmd->policy_hint_size;
1325}
1326
1327static bool hints_array_available(struct dm_cache_metadata *cmd,
1328 struct dm_cache_policy *policy)
1329{
1330 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1331 hints_array_initialized(cmd);
1332}
1333
1334static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1335 uint64_t cb, bool hints_valid,
1336 struct dm_array_cursor *mapping_cursor,
1337 struct dm_array_cursor *hint_cursor,
1338 load_mapping_fn fn, void *context)
1339{
1340 int r = 0;
1341
1342 __le64 mapping;
1343 __le32 hint = 0;
1344
1345 __le64 *mapping_value_le;
1346 __le32 *hint_value_le;
1347
1348 dm_oblock_t oblock;
1349 unsigned int flags;
1350 bool dirty = true;
1351
1352 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1353 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1354 unpack_value(mapping, &oblock, &flags);
1355
1356 if (flags & M_VALID) {
1357 if (hints_valid) {
1358 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1359 memcpy(&hint, hint_value_le, sizeof(hint));
1360 }
1361 if (cmd->clean_when_opened)
1362 dirty = flags & M_DIRTY;
1363
1364 r = fn(context, oblock, to_cblock(cb), dirty,
1365 le32_to_cpu(hint), hints_valid);
1366 if (r) {
1367 DMERR("policy couldn't load cache block %llu",
1368 (unsigned long long) from_cblock(to_cblock(cb)));
1369 }
1370 }
1371
1372 return r;
1373}
1374
1375static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1376 uint64_t cb, bool hints_valid,
1377 struct dm_array_cursor *mapping_cursor,
1378 struct dm_array_cursor *hint_cursor,
1379 struct dm_bitset_cursor *dirty_cursor,
1380 load_mapping_fn fn, void *context)
1381{
1382 int r = 0;
1383
1384 __le64 mapping;
1385 __le32 hint = 0;
1386
1387 __le64 *mapping_value_le;
1388 __le32 *hint_value_le;
1389
1390 dm_oblock_t oblock;
1391 unsigned int flags;
1392 bool dirty = true;
1393
1394 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1395 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1396 unpack_value(mapping, &oblock, &flags);
1397
1398 if (flags & M_VALID) {
1399 if (hints_valid) {
1400 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1401 memcpy(&hint, hint_value_le, sizeof(hint));
1402 }
1403 if (cmd->clean_when_opened)
1404 dirty = dm_bitset_cursor_get_value(dirty_cursor);
1405
1406 r = fn(context, oblock, to_cblock(cb), dirty,
1407 le32_to_cpu(hint), hints_valid);
1408 if (r) {
1409 DMERR("policy couldn't load cache block %llu",
1410 (unsigned long long) from_cblock(to_cblock(cb)));
1411 }
1412 }
1413
1414 return r;
1415}
1416
1417static int __load_mappings(struct dm_cache_metadata *cmd,
1418 struct dm_cache_policy *policy,
1419 load_mapping_fn fn, void *context)
1420{
1421 int r;
1422 uint64_t cb;
1423
1424 bool hints_valid = hints_array_available(cmd, policy);
1425
1426 if (from_cblock(cmd->cache_blocks) == 0)
1427 /* Nothing to do */
1428 return 0;
1429
1430 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1431 if (r)
1432 return r;
1433
1434 if (hints_valid) {
1435 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1436 if (r) {
1437 dm_array_cursor_end(&cmd->mapping_cursor);
1438 return r;
1439 }
1440 }
1441
1442 if (separate_dirty_bits(cmd)) {
1443 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1444 from_cblock(cmd->cache_blocks),
1445 &cmd->dirty_cursor);
1446 if (r) {
1447 dm_array_cursor_end(&cmd->hint_cursor);
1448 dm_array_cursor_end(&cmd->mapping_cursor);
1449 return r;
1450 }
1451 }
1452
1453 for (cb = 0; ; cb++) {
1454 if (separate_dirty_bits(cmd))
1455 r = __load_mapping_v2(cmd, cb, hints_valid,
1456 &cmd->mapping_cursor,
1457 &cmd->hint_cursor,
1458 &cmd->dirty_cursor,
1459 fn, context);
1460 else
1461 r = __load_mapping_v1(cmd, cb, hints_valid,
1462 &cmd->mapping_cursor, &cmd->hint_cursor,
1463 fn, context);
1464 if (r)
1465 goto out;
1466
1467 /*
1468 * We need to break out before we move the cursors.
1469 */
1470 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1471 break;
1472
1473 r = dm_array_cursor_next(&cmd->mapping_cursor);
1474 if (r) {
1475 DMERR("dm_array_cursor_next for mapping failed");
1476 goto out;
1477 }
1478
1479 if (hints_valid) {
1480 r = dm_array_cursor_next(&cmd->hint_cursor);
1481 if (r) {
1482 dm_array_cursor_end(&cmd->hint_cursor);
1483 hints_valid = false;
1484 }
1485 }
1486
1487 if (separate_dirty_bits(cmd)) {
1488 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1489 if (r) {
1490 DMERR("dm_bitset_cursor_next for dirty failed");
1491 goto out;
1492 }
1493 }
1494 }
1495out:
1496 dm_array_cursor_end(&cmd->mapping_cursor);
1497 if (hints_valid)
1498 dm_array_cursor_end(&cmd->hint_cursor);
1499
1500 if (separate_dirty_bits(cmd))
1501 dm_bitset_cursor_end(&cmd->dirty_cursor);
1502
1503 return r;
1504}
1505
1506int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1507 struct dm_cache_policy *policy,
1508 load_mapping_fn fn, void *context)
1509{
1510 int r;
1511
1512 READ_LOCK(cmd);
1513 r = __load_mappings(cmd, policy, fn, context);
1514 READ_UNLOCK(cmd);
1515
1516 return r;
1517}
1518
1519static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1520{
1521 __le64 value;
1522 dm_oblock_t oblock;
1523 unsigned int flags;
1524
1525 memcpy(&value, leaf, sizeof(value));
1526 unpack_value(value, &oblock, &flags);
1527
1528 return 0;
1529}
1530
1531static int __dump_mappings(struct dm_cache_metadata *cmd)
1532{
1533 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1534}
1535
1536void dm_cache_dump(struct dm_cache_metadata *cmd)
1537{
1538 READ_LOCK_VOID(cmd);
1539 __dump_mappings(cmd);
1540 READ_UNLOCK(cmd);
1541}
1542
1543int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1544{
1545 int r;
1546
1547 READ_LOCK(cmd);
1548 r = cmd->changed;
1549 READ_UNLOCK(cmd);
1550
1551 return r;
1552}
1553
1554static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1555{
1556 int r;
1557 unsigned int flags;
1558 dm_oblock_t oblock;
1559 __le64 value;
1560
1561 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1562 if (r)
1563 return r;
1564
1565 unpack_value(value, &oblock, &flags);
1566
1567 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1568 /* nothing to be done */
1569 return 0;
1570
1571 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1572 __dm_bless_for_disk(&value);
1573
1574 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1575 &value, &cmd->root);
1576 if (r)
1577 return r;
1578
1579 cmd->changed = true;
1580 return 0;
1581
1582}
1583
1584static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned int nr_bits, unsigned long *bits)
1585{
1586 int r;
1587 unsigned int i;
1588
1589 for (i = 0; i < nr_bits; i++) {
1590 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1591 if (r)
1592 return r;
1593 }
1594
1595 return 0;
1596}
1597
1598static int is_dirty_callback(uint32_t index, bool *value, void *context)
1599{
1600 unsigned long *bits = context;
1601 *value = test_bit(index, bits);
1602 return 0;
1603}
1604
1605static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned int nr_bits, unsigned long *bits)
1606{
1607 int r = 0;
1608
1609 /* nr_bits is really just a sanity check */
1610 if (nr_bits != from_cblock(cmd->cache_blocks)) {
1611 DMERR("dirty bitset is wrong size");
1612 return -EINVAL;
1613 }
1614
1615 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1616 if (r)
1617 return r;
1618
1619 cmd->changed = true;
1620 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1621}
1622
1623int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1624 unsigned int nr_bits,
1625 unsigned long *bits)
1626{
1627 int r;
1628
1629 WRITE_LOCK(cmd);
1630 if (separate_dirty_bits(cmd))
1631 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1632 else
1633 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1634 WRITE_UNLOCK(cmd);
1635
1636 return r;
1637}
1638
1639void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1640 struct dm_cache_statistics *stats)
1641{
1642 READ_LOCK_VOID(cmd);
1643 *stats = cmd->stats;
1644 READ_UNLOCK(cmd);
1645}
1646
1647void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1648 struct dm_cache_statistics *stats)
1649{
1650 WRITE_LOCK_VOID(cmd);
1651 cmd->stats = *stats;
1652 WRITE_UNLOCK(cmd);
1653}
1654
1655int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1656{
1657 int r = -EINVAL;
1658 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1659 clear_clean_shutdown);
1660
1661 WRITE_LOCK(cmd);
1662 if (cmd->fail_io)
1663 goto out;
1664
1665 r = __commit_transaction(cmd, mutator);
1666 if (r)
1667 goto out;
1668
1669 r = __begin_transaction(cmd);
1670out:
1671 WRITE_UNLOCK(cmd);
1672 return r;
1673}
1674
1675int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1676 dm_block_t *result)
1677{
1678 int r = -EINVAL;
1679
1680 READ_LOCK(cmd);
1681 if (!cmd->fail_io)
1682 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1683 READ_UNLOCK(cmd);
1684
1685 return r;
1686}
1687
1688int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1689 dm_block_t *result)
1690{
1691 int r = -EINVAL;
1692
1693 READ_LOCK(cmd);
1694 if (!cmd->fail_io)
1695 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1696 READ_UNLOCK(cmd);
1697
1698 return r;
1699}
1700
1701/*----------------------------------------------------------------*/
1702
1703static int get_hint(uint32_t index, void *value_le, void *context)
1704{
1705 uint32_t value;
1706 struct dm_cache_policy *policy = context;
1707
1708 value = policy_get_hint(policy, to_cblock(index));
1709 *((__le32 *) value_le) = cpu_to_le32(value);
1710
1711 return 0;
1712}
1713
1714/*
1715 * It's quicker to always delete the hint array, and recreate with
1716 * dm_array_new().
1717 */
1718static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1719{
1720 int r;
1721 size_t hint_size;
1722 const char *policy_name = dm_cache_policy_get_name(policy);
1723 const unsigned int *policy_version = dm_cache_policy_get_version(policy);
1724
1725 if (!policy_name[0] ||
1726 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1727 return -EINVAL;
1728
1729 strscpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1730 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1731
1732 hint_size = dm_cache_policy_get_hint_size(policy);
1733 if (!hint_size)
1734 return 0; /* short-circuit hints initialization */
1735 cmd->policy_hint_size = hint_size;
1736
1737 if (cmd->hint_root) {
1738 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1739 if (r)
1740 return r;
1741 }
1742
1743 return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1744 from_cblock(cmd->cache_blocks),
1745 get_hint, policy);
1746}
1747
1748int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1749{
1750 int r;
1751
1752 WRITE_LOCK(cmd);
1753 r = write_hints(cmd, policy);
1754 WRITE_UNLOCK(cmd);
1755
1756 return r;
1757}
1758
1759int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1760{
1761 int r;
1762
1763 READ_LOCK(cmd);
1764 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1765 READ_UNLOCK(cmd);
1766
1767 return r;
1768}
1769
1770void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1771{
1772 WRITE_LOCK_VOID(cmd);
1773 dm_bm_set_read_only(cmd->bm);
1774 WRITE_UNLOCK(cmd);
1775}
1776
1777void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1778{
1779 WRITE_LOCK_VOID(cmd);
1780 dm_bm_set_read_write(cmd->bm);
1781 WRITE_UNLOCK(cmd);
1782}
1783
1784int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1785{
1786 int r;
1787 struct dm_block *sblock;
1788 struct cache_disk_superblock *disk_super;
1789
1790 WRITE_LOCK(cmd);
1791 set_bit(NEEDS_CHECK, &cmd->flags);
1792
1793 r = superblock_lock(cmd, &sblock);
1794 if (r) {
1795 DMERR("couldn't read superblock");
1796 goto out;
1797 }
1798
1799 disk_super = dm_block_data(sblock);
1800 disk_super->flags = cpu_to_le32(cmd->flags);
1801
1802 dm_bm_unlock(sblock);
1803
1804out:
1805 WRITE_UNLOCK(cmd);
1806 return r;
1807}
1808
1809int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1810{
1811 READ_LOCK(cmd);
1812 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1813 READ_UNLOCK(cmd);
1814
1815 return 0;
1816}
1817
1818int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1819{
1820 int r = -EINVAL;
1821 struct dm_block_manager *old_bm = NULL, *new_bm = NULL;
1822
1823 /* fail_io is double-checked with cmd->root_lock held below */
1824 if (unlikely(cmd->fail_io))
1825 return r;
1826
1827 /*
1828 * Replacement block manager (new_bm) is created and old_bm destroyed outside of
1829 * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
1830 * shrinker associated with the block manager's bufio client vs cmd root_lock).
1831 * - must take shrinker_mutex without holding cmd->root_lock
1832 */
1833 new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
1834 CACHE_MAX_CONCURRENT_LOCKS);
1835
1836 WRITE_LOCK(cmd);
1837 if (cmd->fail_io) {
1838 WRITE_UNLOCK(cmd);
1839 goto out;
1840 }
1841
1842 __destroy_persistent_data_objects(cmd, false);
1843 old_bm = cmd->bm;
1844 if (IS_ERR(new_bm)) {
1845 DMERR("could not create block manager during abort");
1846 cmd->bm = NULL;
1847 r = PTR_ERR(new_bm);
1848 goto out_unlock;
1849 }
1850
1851 cmd->bm = new_bm;
1852 r = __open_or_format_metadata(cmd, false);
1853 if (r) {
1854 cmd->bm = NULL;
1855 goto out_unlock;
1856 }
1857 new_bm = NULL;
1858out_unlock:
1859 if (r)
1860 cmd->fail_io = true;
1861 WRITE_UNLOCK(cmd);
1862 dm_block_manager_destroy(old_bm);
1863out:
1864 if (new_bm && !IS_ERR(new_bm))
1865 dm_block_manager_destroy(new_bm);
1866
1867 return r;
1868}
1/*
2 * Copyright (C) 2012 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-cache-metadata.h"
8
9#include "persistent-data/dm-array.h"
10#include "persistent-data/dm-bitset.h"
11#include "persistent-data/dm-space-map.h"
12#include "persistent-data/dm-space-map-disk.h"
13#include "persistent-data/dm-transaction-manager.h"
14
15#include <linux/device-mapper.h>
16
17/*----------------------------------------------------------------*/
18
19#define DM_MSG_PREFIX "cache metadata"
20
21#define CACHE_SUPERBLOCK_MAGIC 06142003
22#define CACHE_SUPERBLOCK_LOCATION 0
23
24/*
25 * defines a range of metadata versions that this module can handle.
26 */
27#define MIN_CACHE_VERSION 1
28#define MAX_CACHE_VERSION 1
29
30#define CACHE_METADATA_CACHE_SIZE 64
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 */
59 M_DIRTY = 2
60};
61
62struct cache_disk_superblock {
63 __le32 csum;
64 __le32 flags;
65 __le64 blocknr;
66
67 __u8 uuid[16];
68 __le64 magic;
69 __le32 version;
70
71 __u8 policy_name[CACHE_POLICY_NAME_SIZE];
72 __le32 policy_hint_size;
73
74 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
75 __le64 mapping_root;
76 __le64 hint_root;
77
78 __le64 discard_root;
79 __le64 discard_block_size;
80 __le64 discard_nr_blocks;
81
82 __le32 data_block_size;
83 __le32 metadata_block_size;
84 __le32 cache_blocks;
85
86 __le32 compat_flags;
87 __le32 compat_ro_flags;
88 __le32 incompat_flags;
89
90 __le32 read_hits;
91 __le32 read_misses;
92 __le32 write_hits;
93 __le32 write_misses;
94
95 __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
96} __packed;
97
98struct dm_cache_metadata {
99 atomic_t ref_count;
100 struct list_head list;
101
102 struct block_device *bdev;
103 struct dm_block_manager *bm;
104 struct dm_space_map *metadata_sm;
105 struct dm_transaction_manager *tm;
106
107 struct dm_array_info info;
108 struct dm_array_info hint_info;
109 struct dm_disk_bitset discard_info;
110
111 struct rw_semaphore root_lock;
112 unsigned long flags;
113 dm_block_t root;
114 dm_block_t hint_root;
115 dm_block_t discard_root;
116
117 sector_t discard_block_size;
118 dm_dblock_t discard_nr_blocks;
119
120 sector_t data_block_size;
121 dm_cblock_t cache_blocks;
122 bool changed:1;
123 bool clean_when_opened:1;
124
125 char policy_name[CACHE_POLICY_NAME_SIZE];
126 unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
127 size_t policy_hint_size;
128 struct dm_cache_statistics stats;
129
130 /*
131 * Reading the space map root can fail, so we read it into this
132 * buffer before the superblock is locked and updated.
133 */
134 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
135
136 /*
137 * Set if a transaction has to be aborted but the attempt to roll
138 * back to the previous (good) transaction failed. The only
139 * metadata operation permissible in this state is the closing of
140 * the device.
141 */
142 bool fail_io:1;
143};
144
145/*-------------------------------------------------------------------
146 * superblock validator
147 *-----------------------------------------------------------------*/
148
149#define SUPERBLOCK_CSUM_XOR 9031977
150
151static void sb_prepare_for_write(struct dm_block_validator *v,
152 struct dm_block *b,
153 size_t sb_block_size)
154{
155 struct cache_disk_superblock *disk_super = dm_block_data(b);
156
157 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
158 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
159 sb_block_size - sizeof(__le32),
160 SUPERBLOCK_CSUM_XOR));
161}
162
163static int check_metadata_version(struct cache_disk_superblock *disk_super)
164{
165 uint32_t metadata_version = le32_to_cpu(disk_super->version);
166 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
167 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
168 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
169 return -EINVAL;
170 }
171
172 return 0;
173}
174
175static int sb_check(struct dm_block_validator *v,
176 struct dm_block *b,
177 size_t sb_block_size)
178{
179 struct cache_disk_superblock *disk_super = dm_block_data(b);
180 __le32 csum_le;
181
182 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
183 DMERR("sb_check failed: blocknr %llu: wanted %llu",
184 le64_to_cpu(disk_super->blocknr),
185 (unsigned long long)dm_block_location(b));
186 return -ENOTBLK;
187 }
188
189 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
190 DMERR("sb_check failed: magic %llu: wanted %llu",
191 le64_to_cpu(disk_super->magic),
192 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
193 return -EILSEQ;
194 }
195
196 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
197 sb_block_size - sizeof(__le32),
198 SUPERBLOCK_CSUM_XOR));
199 if (csum_le != disk_super->csum) {
200 DMERR("sb_check failed: csum %u: wanted %u",
201 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
202 return -EILSEQ;
203 }
204
205 return check_metadata_version(disk_super);
206}
207
208static struct dm_block_validator sb_validator = {
209 .name = "superblock",
210 .prepare_for_write = sb_prepare_for_write,
211 .check = sb_check
212};
213
214/*----------------------------------------------------------------*/
215
216static int superblock_read_lock(struct dm_cache_metadata *cmd,
217 struct dm_block **sblock)
218{
219 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
220 &sb_validator, sblock);
221}
222
223static int superblock_lock_zero(struct dm_cache_metadata *cmd,
224 struct dm_block **sblock)
225{
226 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
227 &sb_validator, sblock);
228}
229
230static int superblock_lock(struct dm_cache_metadata *cmd,
231 struct dm_block **sblock)
232{
233 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
234 &sb_validator, sblock);
235}
236
237/*----------------------------------------------------------------*/
238
239static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
240{
241 int r;
242 unsigned i;
243 struct dm_block *b;
244 __le64 *data_le, zero = cpu_to_le64(0);
245 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
246
247 /*
248 * We can't use a validator here - it may be all zeroes.
249 */
250 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
251 if (r)
252 return r;
253
254 data_le = dm_block_data(b);
255 *result = true;
256 for (i = 0; i < sb_block_size; i++) {
257 if (data_le[i] != zero) {
258 *result = false;
259 break;
260 }
261 }
262
263 dm_bm_unlock(b);
264
265 return 0;
266}
267
268static void __setup_mapping_info(struct dm_cache_metadata *cmd)
269{
270 struct dm_btree_value_type vt;
271
272 vt.context = NULL;
273 vt.size = sizeof(__le64);
274 vt.inc = NULL;
275 vt.dec = NULL;
276 vt.equal = NULL;
277 dm_array_info_init(&cmd->info, cmd->tm, &vt);
278
279 if (cmd->policy_hint_size) {
280 vt.size = sizeof(__le32);
281 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
282 }
283}
284
285static int __save_sm_root(struct dm_cache_metadata *cmd)
286{
287 int r;
288 size_t metadata_len;
289
290 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
291 if (r < 0)
292 return r;
293
294 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
295 metadata_len);
296}
297
298static void __copy_sm_root(struct dm_cache_metadata *cmd,
299 struct cache_disk_superblock *disk_super)
300{
301 memcpy(&disk_super->metadata_space_map_root,
302 &cmd->metadata_space_map_root,
303 sizeof(cmd->metadata_space_map_root));
304}
305
306static int __write_initial_superblock(struct dm_cache_metadata *cmd)
307{
308 int r;
309 struct dm_block *sblock;
310 struct cache_disk_superblock *disk_super;
311 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
312
313 /* FIXME: see if we can lose the max sectors limit */
314 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
315 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
316
317 r = dm_tm_pre_commit(cmd->tm);
318 if (r < 0)
319 return r;
320
321 /*
322 * dm_sm_copy_root() can fail. So we need to do it before we start
323 * updating the superblock.
324 */
325 r = __save_sm_root(cmd);
326 if (r)
327 return r;
328
329 r = superblock_lock_zero(cmd, &sblock);
330 if (r)
331 return r;
332
333 disk_super = dm_block_data(sblock);
334 disk_super->flags = 0;
335 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
336 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
337 disk_super->version = cpu_to_le32(MAX_CACHE_VERSION);
338 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
339 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
340 disk_super->policy_hint_size = 0;
341
342 __copy_sm_root(cmd, disk_super);
343
344 disk_super->mapping_root = cpu_to_le64(cmd->root);
345 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
346 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
347 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
348 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
349 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
350 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
351 disk_super->cache_blocks = cpu_to_le32(0);
352
353 disk_super->read_hits = cpu_to_le32(0);
354 disk_super->read_misses = cpu_to_le32(0);
355 disk_super->write_hits = cpu_to_le32(0);
356 disk_super->write_misses = cpu_to_le32(0);
357
358 return dm_tm_commit(cmd->tm, sblock);
359}
360
361static int __format_metadata(struct dm_cache_metadata *cmd)
362{
363 int r;
364
365 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
366 &cmd->tm, &cmd->metadata_sm);
367 if (r < 0) {
368 DMERR("tm_create_with_sm failed");
369 return r;
370 }
371
372 __setup_mapping_info(cmd);
373
374 r = dm_array_empty(&cmd->info, &cmd->root);
375 if (r < 0)
376 goto bad;
377
378 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
379
380 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
381 if (r < 0)
382 goto bad;
383
384 cmd->discard_block_size = 0;
385 cmd->discard_nr_blocks = 0;
386
387 r = __write_initial_superblock(cmd);
388 if (r)
389 goto bad;
390
391 cmd->clean_when_opened = true;
392 return 0;
393
394bad:
395 dm_tm_destroy(cmd->tm);
396 dm_sm_destroy(cmd->metadata_sm);
397
398 return r;
399}
400
401static int __check_incompat_features(struct cache_disk_superblock *disk_super,
402 struct dm_cache_metadata *cmd)
403{
404 uint32_t features;
405
406 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
407 if (features) {
408 DMERR("could not access metadata due to unsupported optional features (%lx).",
409 (unsigned long)features);
410 return -EINVAL;
411 }
412
413 /*
414 * Check for read-only metadata to skip the following RDWR checks.
415 */
416 if (get_disk_ro(cmd->bdev->bd_disk))
417 return 0;
418
419 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
420 if (features) {
421 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
422 (unsigned long)features);
423 return -EINVAL;
424 }
425
426 return 0;
427}
428
429static int __open_metadata(struct dm_cache_metadata *cmd)
430{
431 int r;
432 struct dm_block *sblock;
433 struct cache_disk_superblock *disk_super;
434 unsigned long sb_flags;
435
436 r = superblock_read_lock(cmd, &sblock);
437 if (r < 0) {
438 DMERR("couldn't read lock superblock");
439 return r;
440 }
441
442 disk_super = dm_block_data(sblock);
443
444 /* Verify the data block size hasn't changed */
445 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
446 DMERR("changing the data block size (from %u to %llu) is not supported",
447 le32_to_cpu(disk_super->data_block_size),
448 (unsigned long long)cmd->data_block_size);
449 r = -EINVAL;
450 goto bad;
451 }
452
453 r = __check_incompat_features(disk_super, cmd);
454 if (r < 0)
455 goto bad;
456
457 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
458 disk_super->metadata_space_map_root,
459 sizeof(disk_super->metadata_space_map_root),
460 &cmd->tm, &cmd->metadata_sm);
461 if (r < 0) {
462 DMERR("tm_open_with_sm failed");
463 goto bad;
464 }
465
466 __setup_mapping_info(cmd);
467 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
468 sb_flags = le32_to_cpu(disk_super->flags);
469 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
470 dm_bm_unlock(sblock);
471
472 return 0;
473
474bad:
475 dm_bm_unlock(sblock);
476 return r;
477}
478
479static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
480 bool format_device)
481{
482 int r;
483 bool unformatted = false;
484
485 r = __superblock_all_zeroes(cmd->bm, &unformatted);
486 if (r)
487 return r;
488
489 if (unformatted)
490 return format_device ? __format_metadata(cmd) : -EPERM;
491
492 return __open_metadata(cmd);
493}
494
495static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
496 bool may_format_device)
497{
498 int r;
499 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
500 CACHE_METADATA_CACHE_SIZE,
501 CACHE_MAX_CONCURRENT_LOCKS);
502 if (IS_ERR(cmd->bm)) {
503 DMERR("could not create block manager");
504 return PTR_ERR(cmd->bm);
505 }
506
507 r = __open_or_format_metadata(cmd, may_format_device);
508 if (r)
509 dm_block_manager_destroy(cmd->bm);
510
511 return r;
512}
513
514static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
515{
516 dm_sm_destroy(cmd->metadata_sm);
517 dm_tm_destroy(cmd->tm);
518 dm_block_manager_destroy(cmd->bm);
519}
520
521typedef unsigned long (*flags_mutator)(unsigned long);
522
523static void update_flags(struct cache_disk_superblock *disk_super,
524 flags_mutator mutator)
525{
526 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
527 disk_super->flags = cpu_to_le32(sb_flags);
528}
529
530static unsigned long set_clean_shutdown(unsigned long flags)
531{
532 set_bit(CLEAN_SHUTDOWN, &flags);
533 return flags;
534}
535
536static unsigned long clear_clean_shutdown(unsigned long flags)
537{
538 clear_bit(CLEAN_SHUTDOWN, &flags);
539 return flags;
540}
541
542static void read_superblock_fields(struct dm_cache_metadata *cmd,
543 struct cache_disk_superblock *disk_super)
544{
545 cmd->flags = le32_to_cpu(disk_super->flags);
546 cmd->root = le64_to_cpu(disk_super->mapping_root);
547 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
548 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
549 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
550 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
551 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
552 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
553 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
554 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
555 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
556 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
557 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
558
559 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
560 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
561 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
562 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
563
564 cmd->changed = false;
565}
566
567/*
568 * The mutator updates the superblock flags.
569 */
570static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
571 flags_mutator mutator)
572{
573 int r;
574 struct cache_disk_superblock *disk_super;
575 struct dm_block *sblock;
576
577 r = superblock_lock(cmd, &sblock);
578 if (r)
579 return r;
580
581 disk_super = dm_block_data(sblock);
582 update_flags(disk_super, mutator);
583 read_superblock_fields(cmd, disk_super);
584 dm_bm_unlock(sblock);
585
586 return dm_bm_flush(cmd->bm);
587}
588
589static int __begin_transaction(struct dm_cache_metadata *cmd)
590{
591 int r;
592 struct cache_disk_superblock *disk_super;
593 struct dm_block *sblock;
594
595 /*
596 * We re-read the superblock every time. Shouldn't need to do this
597 * really.
598 */
599 r = superblock_read_lock(cmd, &sblock);
600 if (r)
601 return r;
602
603 disk_super = dm_block_data(sblock);
604 read_superblock_fields(cmd, disk_super);
605 dm_bm_unlock(sblock);
606
607 return 0;
608}
609
610static int __commit_transaction(struct dm_cache_metadata *cmd,
611 flags_mutator mutator)
612{
613 int r;
614 struct cache_disk_superblock *disk_super;
615 struct dm_block *sblock;
616
617 /*
618 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
619 */
620 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
621
622 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
623 &cmd->discard_root);
624 if (r)
625 return r;
626
627 r = dm_tm_pre_commit(cmd->tm);
628 if (r < 0)
629 return r;
630
631 r = __save_sm_root(cmd);
632 if (r)
633 return r;
634
635 r = superblock_lock(cmd, &sblock);
636 if (r)
637 return r;
638
639 disk_super = dm_block_data(sblock);
640
641 disk_super->flags = cpu_to_le32(cmd->flags);
642 if (mutator)
643 update_flags(disk_super, mutator);
644
645 disk_super->mapping_root = cpu_to_le64(cmd->root);
646 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
647 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
648 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
649 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
650 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
651 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
652 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
653 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
654 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
655
656 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
657 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
658 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
659 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
660 __copy_sm_root(cmd, disk_super);
661
662 return dm_tm_commit(cmd->tm, sblock);
663}
664
665/*----------------------------------------------------------------*/
666
667/*
668 * The mappings are held in a dm-array that has 64-bit values stored in
669 * little-endian format. The index is the cblock, the high 48bits of the
670 * value are the oblock and the low 16 bit the flags.
671 */
672#define FLAGS_MASK ((1 << 16) - 1)
673
674static __le64 pack_value(dm_oblock_t block, unsigned flags)
675{
676 uint64_t value = from_oblock(block);
677 value <<= 16;
678 value = value | (flags & FLAGS_MASK);
679 return cpu_to_le64(value);
680}
681
682static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
683{
684 uint64_t value = le64_to_cpu(value_le);
685 uint64_t b = value >> 16;
686 *block = to_oblock(b);
687 *flags = value & FLAGS_MASK;
688}
689
690/*----------------------------------------------------------------*/
691
692static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
693 sector_t data_block_size,
694 bool may_format_device,
695 size_t policy_hint_size)
696{
697 int r;
698 struct dm_cache_metadata *cmd;
699
700 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
701 if (!cmd) {
702 DMERR("could not allocate metadata struct");
703 return ERR_PTR(-ENOMEM);
704 }
705
706 atomic_set(&cmd->ref_count, 1);
707 init_rwsem(&cmd->root_lock);
708 cmd->bdev = bdev;
709 cmd->data_block_size = data_block_size;
710 cmd->cache_blocks = 0;
711 cmd->policy_hint_size = policy_hint_size;
712 cmd->changed = true;
713 cmd->fail_io = false;
714
715 r = __create_persistent_data_objects(cmd, may_format_device);
716 if (r) {
717 kfree(cmd);
718 return ERR_PTR(r);
719 }
720
721 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
722 if (r < 0) {
723 dm_cache_metadata_close(cmd);
724 return ERR_PTR(r);
725 }
726
727 return cmd;
728}
729
730/*
731 * We keep a little list of ref counted metadata objects to prevent two
732 * different target instances creating separate bufio instances. This is
733 * an issue if a table is reloaded before the suspend.
734 */
735static DEFINE_MUTEX(table_lock);
736static LIST_HEAD(table);
737
738static struct dm_cache_metadata *lookup(struct block_device *bdev)
739{
740 struct dm_cache_metadata *cmd;
741
742 list_for_each_entry(cmd, &table, list)
743 if (cmd->bdev == bdev) {
744 atomic_inc(&cmd->ref_count);
745 return cmd;
746 }
747
748 return NULL;
749}
750
751static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
752 sector_t data_block_size,
753 bool may_format_device,
754 size_t policy_hint_size)
755{
756 struct dm_cache_metadata *cmd, *cmd2;
757
758 mutex_lock(&table_lock);
759 cmd = lookup(bdev);
760 mutex_unlock(&table_lock);
761
762 if (cmd)
763 return cmd;
764
765 cmd = metadata_open(bdev, data_block_size, may_format_device, policy_hint_size);
766 if (!IS_ERR(cmd)) {
767 mutex_lock(&table_lock);
768 cmd2 = lookup(bdev);
769 if (cmd2) {
770 mutex_unlock(&table_lock);
771 __destroy_persistent_data_objects(cmd);
772 kfree(cmd);
773 return cmd2;
774 }
775 list_add(&cmd->list, &table);
776 mutex_unlock(&table_lock);
777 }
778
779 return cmd;
780}
781
782static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
783{
784 if (cmd->data_block_size != data_block_size) {
785 DMERR("data_block_size (%llu) different from that in metadata (%llu)\n",
786 (unsigned long long) data_block_size,
787 (unsigned long long) cmd->data_block_size);
788 return false;
789 }
790
791 return true;
792}
793
794struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
795 sector_t data_block_size,
796 bool may_format_device,
797 size_t policy_hint_size)
798{
799 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size,
800 may_format_device, policy_hint_size);
801
802 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
803 dm_cache_metadata_close(cmd);
804 return ERR_PTR(-EINVAL);
805 }
806
807 return cmd;
808}
809
810void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
811{
812 if (atomic_dec_and_test(&cmd->ref_count)) {
813 mutex_lock(&table_lock);
814 list_del(&cmd->list);
815 mutex_unlock(&table_lock);
816
817 if (!cmd->fail_io)
818 __destroy_persistent_data_objects(cmd);
819 kfree(cmd);
820 }
821}
822
823/*
824 * Checks that the given cache block is either unmapped or clean.
825 */
826static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
827 bool *result)
828{
829 int r;
830 __le64 value;
831 dm_oblock_t ob;
832 unsigned flags;
833
834 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
835 if (r) {
836 DMERR("block_unmapped_or_clean failed");
837 return r;
838 }
839
840 unpack_value(value, &ob, &flags);
841 *result = !((flags & M_VALID) && (flags & M_DIRTY));
842
843 return 0;
844}
845
846static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
847 dm_cblock_t begin, dm_cblock_t end,
848 bool *result)
849{
850 int r;
851 *result = true;
852
853 while (begin != end) {
854 r = block_unmapped_or_clean(cmd, begin, result);
855 if (r)
856 return r;
857
858 if (!*result) {
859 DMERR("cache block %llu is dirty",
860 (unsigned long long) from_cblock(begin));
861 return 0;
862 }
863
864 begin = to_cblock(from_cblock(begin) + 1);
865 }
866
867 return 0;
868}
869
870static bool cmd_write_lock(struct dm_cache_metadata *cmd)
871{
872 down_write(&cmd->root_lock);
873 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
874 up_write(&cmd->root_lock);
875 return false;
876 }
877 return true;
878}
879
880#define WRITE_LOCK(cmd) \
881 do { \
882 if (!cmd_write_lock((cmd))) \
883 return -EINVAL; \
884 } while(0)
885
886#define WRITE_LOCK_VOID(cmd) \
887 do { \
888 if (!cmd_write_lock((cmd))) \
889 return; \
890 } while(0)
891
892#define WRITE_UNLOCK(cmd) \
893 up_write(&(cmd)->root_lock)
894
895static bool cmd_read_lock(struct dm_cache_metadata *cmd)
896{
897 down_read(&cmd->root_lock);
898 if (cmd->fail_io) {
899 up_read(&cmd->root_lock);
900 return false;
901 }
902 return true;
903}
904
905#define READ_LOCK(cmd) \
906 do { \
907 if (!cmd_read_lock((cmd))) \
908 return -EINVAL; \
909 } while(0)
910
911#define READ_LOCK_VOID(cmd) \
912 do { \
913 if (!cmd_read_lock((cmd))) \
914 return; \
915 } while(0)
916
917#define READ_UNLOCK(cmd) \
918 up_read(&(cmd)->root_lock)
919
920int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
921{
922 int r;
923 bool clean;
924 __le64 null_mapping = pack_value(0, 0);
925
926 WRITE_LOCK(cmd);
927 __dm_bless_for_disk(&null_mapping);
928
929 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
930 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
931 if (r) {
932 __dm_unbless_for_disk(&null_mapping);
933 goto out;
934 }
935
936 if (!clean) {
937 DMERR("unable to shrink cache due to dirty blocks");
938 r = -EINVAL;
939 __dm_unbless_for_disk(&null_mapping);
940 goto out;
941 }
942 }
943
944 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
945 from_cblock(new_cache_size),
946 &null_mapping, &cmd->root);
947 if (!r)
948 cmd->cache_blocks = new_cache_size;
949 cmd->changed = true;
950
951out:
952 WRITE_UNLOCK(cmd);
953
954 return r;
955}
956
957int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
958 sector_t discard_block_size,
959 dm_dblock_t new_nr_entries)
960{
961 int r;
962
963 WRITE_LOCK(cmd);
964 r = dm_bitset_resize(&cmd->discard_info,
965 cmd->discard_root,
966 from_dblock(cmd->discard_nr_blocks),
967 from_dblock(new_nr_entries),
968 false, &cmd->discard_root);
969 if (!r) {
970 cmd->discard_block_size = discard_block_size;
971 cmd->discard_nr_blocks = new_nr_entries;
972 }
973
974 cmd->changed = true;
975 WRITE_UNLOCK(cmd);
976
977 return r;
978}
979
980static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
981{
982 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
983 from_dblock(b), &cmd->discard_root);
984}
985
986static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
987{
988 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
989 from_dblock(b), &cmd->discard_root);
990}
991
992static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
993 bool *is_discarded)
994{
995 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
996 from_dblock(b), &cmd->discard_root,
997 is_discarded);
998}
999
1000static int __discard(struct dm_cache_metadata *cmd,
1001 dm_dblock_t dblock, bool discard)
1002{
1003 int r;
1004
1005 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1006 if (r)
1007 return r;
1008
1009 cmd->changed = true;
1010 return 0;
1011}
1012
1013int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1014 dm_dblock_t dblock, bool discard)
1015{
1016 int r;
1017
1018 WRITE_LOCK(cmd);
1019 r = __discard(cmd, dblock, discard);
1020 WRITE_UNLOCK(cmd);
1021
1022 return r;
1023}
1024
1025static int __load_discards(struct dm_cache_metadata *cmd,
1026 load_discard_fn fn, void *context)
1027{
1028 int r = 0;
1029 dm_block_t b;
1030 bool discard;
1031
1032 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1033 dm_dblock_t dblock = to_dblock(b);
1034
1035 if (cmd->clean_when_opened) {
1036 r = __is_discarded(cmd, dblock, &discard);
1037 if (r)
1038 return r;
1039 } else
1040 discard = false;
1041
1042 r = fn(context, cmd->discard_block_size, dblock, discard);
1043 if (r)
1044 break;
1045 }
1046
1047 return r;
1048}
1049
1050int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1051 load_discard_fn fn, void *context)
1052{
1053 int r;
1054
1055 READ_LOCK(cmd);
1056 r = __load_discards(cmd, fn, context);
1057 READ_UNLOCK(cmd);
1058
1059 return r;
1060}
1061
1062int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1063{
1064 READ_LOCK(cmd);
1065 *result = cmd->cache_blocks;
1066 READ_UNLOCK(cmd);
1067
1068 return 0;
1069}
1070
1071static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1072{
1073 int r;
1074 __le64 value = pack_value(0, 0);
1075
1076 __dm_bless_for_disk(&value);
1077 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1078 &value, &cmd->root);
1079 if (r)
1080 return r;
1081
1082 cmd->changed = true;
1083 return 0;
1084}
1085
1086int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1087{
1088 int r;
1089
1090 WRITE_LOCK(cmd);
1091 r = __remove(cmd, cblock);
1092 WRITE_UNLOCK(cmd);
1093
1094 return r;
1095}
1096
1097static int __insert(struct dm_cache_metadata *cmd,
1098 dm_cblock_t cblock, dm_oblock_t oblock)
1099{
1100 int r;
1101 __le64 value = pack_value(oblock, M_VALID);
1102 __dm_bless_for_disk(&value);
1103
1104 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1105 &value, &cmd->root);
1106 if (r)
1107 return r;
1108
1109 cmd->changed = true;
1110 return 0;
1111}
1112
1113int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1114 dm_cblock_t cblock, dm_oblock_t oblock)
1115{
1116 int r;
1117
1118 WRITE_LOCK(cmd);
1119 r = __insert(cmd, cblock, oblock);
1120 WRITE_UNLOCK(cmd);
1121
1122 return r;
1123}
1124
1125struct thunk {
1126 load_mapping_fn fn;
1127 void *context;
1128
1129 struct dm_cache_metadata *cmd;
1130 bool respect_dirty_flags;
1131 bool hints_valid;
1132};
1133
1134static bool policy_unchanged(struct dm_cache_metadata *cmd,
1135 struct dm_cache_policy *policy)
1136{
1137 const char *policy_name = dm_cache_policy_get_name(policy);
1138 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1139 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1140
1141 /*
1142 * Ensure policy names match.
1143 */
1144 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1145 return false;
1146
1147 /*
1148 * Ensure policy major versions match.
1149 */
1150 if (cmd->policy_version[0] != policy_version[0])
1151 return false;
1152
1153 /*
1154 * Ensure policy hint sizes match.
1155 */
1156 if (cmd->policy_hint_size != policy_hint_size)
1157 return false;
1158
1159 return true;
1160}
1161
1162static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1163{
1164 return cmd->hint_root && cmd->policy_hint_size;
1165}
1166
1167static bool hints_array_available(struct dm_cache_metadata *cmd,
1168 struct dm_cache_policy *policy)
1169{
1170 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1171 hints_array_initialized(cmd);
1172}
1173
1174static int __load_mapping(void *context, uint64_t cblock, void *leaf)
1175{
1176 int r = 0;
1177 bool dirty;
1178 __le64 value;
1179 __le32 hint_value = 0;
1180 dm_oblock_t oblock;
1181 unsigned flags;
1182 struct thunk *thunk = context;
1183 struct dm_cache_metadata *cmd = thunk->cmd;
1184
1185 memcpy(&value, leaf, sizeof(value));
1186 unpack_value(value, &oblock, &flags);
1187
1188 if (flags & M_VALID) {
1189 if (thunk->hints_valid) {
1190 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,
1191 cblock, &hint_value);
1192 if (r && r != -ENODATA)
1193 return r;
1194 }
1195
1196 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;
1197 r = thunk->fn(thunk->context, oblock, to_cblock(cblock),
1198 dirty, le32_to_cpu(hint_value), thunk->hints_valid);
1199 }
1200
1201 return r;
1202}
1203
1204static int __load_mappings(struct dm_cache_metadata *cmd,
1205 struct dm_cache_policy *policy,
1206 load_mapping_fn fn, void *context)
1207{
1208 struct thunk thunk;
1209
1210 thunk.fn = fn;
1211 thunk.context = context;
1212
1213 thunk.cmd = cmd;
1214 thunk.respect_dirty_flags = cmd->clean_when_opened;
1215 thunk.hints_valid = hints_array_available(cmd, policy);
1216
1217 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);
1218}
1219
1220int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1221 struct dm_cache_policy *policy,
1222 load_mapping_fn fn, void *context)
1223{
1224 int r;
1225
1226 READ_LOCK(cmd);
1227 r = __load_mappings(cmd, policy, fn, context);
1228 READ_UNLOCK(cmd);
1229
1230 return r;
1231}
1232
1233static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1234{
1235 int r = 0;
1236 __le64 value;
1237 dm_oblock_t oblock;
1238 unsigned flags;
1239
1240 memcpy(&value, leaf, sizeof(value));
1241 unpack_value(value, &oblock, &flags);
1242
1243 return r;
1244}
1245
1246static int __dump_mappings(struct dm_cache_metadata *cmd)
1247{
1248 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1249}
1250
1251void dm_cache_dump(struct dm_cache_metadata *cmd)
1252{
1253 READ_LOCK_VOID(cmd);
1254 __dump_mappings(cmd);
1255 READ_UNLOCK(cmd);
1256}
1257
1258int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1259{
1260 int r;
1261
1262 READ_LOCK(cmd);
1263 r = cmd->changed;
1264 READ_UNLOCK(cmd);
1265
1266 return r;
1267}
1268
1269static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1270{
1271 int r;
1272 unsigned flags;
1273 dm_oblock_t oblock;
1274 __le64 value;
1275
1276 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1277 if (r)
1278 return r;
1279
1280 unpack_value(value, &oblock, &flags);
1281
1282 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1283 /* nothing to be done */
1284 return 0;
1285
1286 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1287 __dm_bless_for_disk(&value);
1288
1289 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1290 &value, &cmd->root);
1291 if (r)
1292 return r;
1293
1294 cmd->changed = true;
1295 return 0;
1296
1297}
1298
1299int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
1300 dm_cblock_t cblock, bool dirty)
1301{
1302 int r;
1303
1304 WRITE_LOCK(cmd);
1305 r = __dirty(cmd, cblock, dirty);
1306 WRITE_UNLOCK(cmd);
1307
1308 return r;
1309}
1310
1311void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1312 struct dm_cache_statistics *stats)
1313{
1314 READ_LOCK_VOID(cmd);
1315 *stats = cmd->stats;
1316 READ_UNLOCK(cmd);
1317}
1318
1319void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1320 struct dm_cache_statistics *stats)
1321{
1322 WRITE_LOCK_VOID(cmd);
1323 cmd->stats = *stats;
1324 WRITE_UNLOCK(cmd);
1325}
1326
1327int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1328{
1329 int r;
1330 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1331 clear_clean_shutdown);
1332
1333 WRITE_LOCK(cmd);
1334 r = __commit_transaction(cmd, mutator);
1335 if (r)
1336 goto out;
1337
1338 r = __begin_transaction(cmd);
1339
1340out:
1341 WRITE_UNLOCK(cmd);
1342 return r;
1343}
1344
1345int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1346 dm_block_t *result)
1347{
1348 int r = -EINVAL;
1349
1350 READ_LOCK(cmd);
1351 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1352 READ_UNLOCK(cmd);
1353
1354 return r;
1355}
1356
1357int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1358 dm_block_t *result)
1359{
1360 int r = -EINVAL;
1361
1362 READ_LOCK(cmd);
1363 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1364 READ_UNLOCK(cmd);
1365
1366 return r;
1367}
1368
1369/*----------------------------------------------------------------*/
1370
1371static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1372{
1373 int r;
1374 __le32 value;
1375 size_t hint_size;
1376 const char *policy_name = dm_cache_policy_get_name(policy);
1377 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1378
1379 if (!policy_name[0] ||
1380 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1381 return -EINVAL;
1382
1383 if (!policy_unchanged(cmd, policy)) {
1384 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1385 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1386
1387 hint_size = dm_cache_policy_get_hint_size(policy);
1388 if (!hint_size)
1389 return 0; /* short-circuit hints initialization */
1390 cmd->policy_hint_size = hint_size;
1391
1392 if (cmd->hint_root) {
1393 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1394 if (r)
1395 return r;
1396 }
1397
1398 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root);
1399 if (r)
1400 return r;
1401
1402 value = cpu_to_le32(0);
1403 __dm_bless_for_disk(&value);
1404 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0,
1405 from_cblock(cmd->cache_blocks),
1406 &value, &cmd->hint_root);
1407 if (r)
1408 return r;
1409 }
1410
1411 return 0;
1412}
1413
1414static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, uint32_t hint)
1415{
1416 struct dm_cache_metadata *cmd = context;
1417 __le32 value = cpu_to_le32(hint);
1418 int r;
1419
1420 __dm_bless_for_disk(&value);
1421
1422 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
1423 from_cblock(cblock), &value, &cmd->hint_root);
1424 cmd->changed = true;
1425
1426 return r;
1427}
1428
1429static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1430{
1431 int r;
1432
1433 r = begin_hints(cmd, policy);
1434 if (r) {
1435 DMERR("begin_hints failed");
1436 return r;
1437 }
1438
1439 return policy_walk_mappings(policy, save_hint, cmd);
1440}
1441
1442int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1443{
1444 int r;
1445
1446 WRITE_LOCK(cmd);
1447 r = write_hints(cmd, policy);
1448 WRITE_UNLOCK(cmd);
1449
1450 return r;
1451}
1452
1453int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1454{
1455 int r;
1456
1457 READ_LOCK(cmd);
1458 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1459 READ_UNLOCK(cmd);
1460
1461 return r;
1462}
1463
1464void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1465{
1466 WRITE_LOCK_VOID(cmd);
1467 dm_bm_set_read_only(cmd->bm);
1468 WRITE_UNLOCK(cmd);
1469}
1470
1471void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1472{
1473 WRITE_LOCK_VOID(cmd);
1474 dm_bm_set_read_write(cmd->bm);
1475 WRITE_UNLOCK(cmd);
1476}
1477
1478int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1479{
1480 int r;
1481 struct dm_block *sblock;
1482 struct cache_disk_superblock *disk_super;
1483
1484 WRITE_LOCK(cmd);
1485 set_bit(NEEDS_CHECK, &cmd->flags);
1486
1487 r = superblock_lock(cmd, &sblock);
1488 if (r) {
1489 DMERR("couldn't read superblock");
1490 goto out;
1491 }
1492
1493 disk_super = dm_block_data(sblock);
1494 disk_super->flags = cpu_to_le32(cmd->flags);
1495
1496 dm_bm_unlock(sblock);
1497
1498out:
1499 WRITE_UNLOCK(cmd);
1500 return r;
1501}
1502
1503int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1504{
1505 READ_LOCK(cmd);
1506 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1507 READ_UNLOCK(cmd);
1508
1509 return 0;
1510}
1511
1512int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1513{
1514 int r;
1515
1516 WRITE_LOCK(cmd);
1517 __destroy_persistent_data_objects(cmd);
1518 r = __create_persistent_data_objects(cmd, false);
1519 if (r)
1520 cmd->fail_io = true;
1521 WRITE_UNLOCK(cmd);
1522
1523 return r;
1524}