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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#include <linux/refcount.h>
17
18/*----------------------------------------------------------------*/
19
20#define DM_MSG_PREFIX "cache metadata"
21
22#define CACHE_SUPERBLOCK_MAGIC 06142003
23#define CACHE_SUPERBLOCK_LOCATION 0
24
25/*
26 * defines a range of metadata versions that this module can handle.
27 */
28#define MIN_CACHE_VERSION 1
29#define MAX_CACHE_VERSION 2
30
31/*
32 * 3 for btree insert +
33 * 2 for btree lookup used within space map
34 */
35#define CACHE_MAX_CONCURRENT_LOCKS 5
36#define SPACE_MAP_ROOT_SIZE 128
37
38enum superblock_flag_bits {
39 /* for spotting crashes that would invalidate the dirty bitset */
40 CLEAN_SHUTDOWN,
41 /* metadata must be checked using the tools */
42 NEEDS_CHECK,
43};
44
45/*
46 * Each mapping from cache block -> origin block carries a set of flags.
47 */
48enum mapping_bits {
49 /*
50 * A valid mapping. Because we're using an array we clear this
51 * flag for an non existant mapping.
52 */
53 M_VALID = 1,
54
55 /*
56 * The data on the cache is different from that on the origin.
57 * This flag is only used by metadata format 1.
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
97 /*
98 * Metadata format 2 fields.
99 */
100 __le64 dirty_root;
101} __packed;
102
103struct dm_cache_metadata {
104 refcount_t ref_count;
105 struct list_head list;
106
107 unsigned version;
108 struct block_device *bdev;
109 struct dm_block_manager *bm;
110 struct dm_space_map *metadata_sm;
111 struct dm_transaction_manager *tm;
112
113 struct dm_array_info info;
114 struct dm_array_info hint_info;
115 struct dm_disk_bitset discard_info;
116
117 struct rw_semaphore root_lock;
118 unsigned long flags;
119 dm_block_t root;
120 dm_block_t hint_root;
121 dm_block_t discard_root;
122
123 sector_t discard_block_size;
124 dm_dblock_t discard_nr_blocks;
125
126 sector_t data_block_size;
127 dm_cblock_t cache_blocks;
128 bool changed:1;
129 bool clean_when_opened:1;
130
131 char policy_name[CACHE_POLICY_NAME_SIZE];
132 unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
133 size_t policy_hint_size;
134 struct dm_cache_statistics stats;
135
136 /*
137 * Reading the space map root can fail, so we read it into this
138 * buffer before the superblock is locked and updated.
139 */
140 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
141
142 /*
143 * Set if a transaction has to be aborted but the attempt to roll
144 * back to the previous (good) transaction failed. The only
145 * metadata operation permissible in this state is the closing of
146 * the device.
147 */
148 bool fail_io:1;
149
150 /*
151 * Metadata format 2 fields.
152 */
153 dm_block_t dirty_root;
154 struct dm_disk_bitset dirty_info;
155
156 /*
157 * These structures are used when loading metadata. They're too
158 * big to put on the stack.
159 */
160 struct dm_array_cursor mapping_cursor;
161 struct dm_array_cursor hint_cursor;
162 struct dm_bitset_cursor dirty_cursor;
163};
164
165/*-------------------------------------------------------------------
166 * superblock validator
167 *-----------------------------------------------------------------*/
168
169#define SUPERBLOCK_CSUM_XOR 9031977
170
171static void sb_prepare_for_write(struct dm_block_validator *v,
172 struct dm_block *b,
173 size_t sb_block_size)
174{
175 struct cache_disk_superblock *disk_super = dm_block_data(b);
176
177 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
178 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
179 sb_block_size - sizeof(__le32),
180 SUPERBLOCK_CSUM_XOR));
181}
182
183static int check_metadata_version(struct cache_disk_superblock *disk_super)
184{
185 uint32_t metadata_version = le32_to_cpu(disk_super->version);
186
187 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
188 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
189 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
190 return -EINVAL;
191 }
192
193 return 0;
194}
195
196static int sb_check(struct dm_block_validator *v,
197 struct dm_block *b,
198 size_t sb_block_size)
199{
200 struct cache_disk_superblock *disk_super = dm_block_data(b);
201 __le32 csum_le;
202
203 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
204 DMERR("sb_check failed: blocknr %llu: wanted %llu",
205 le64_to_cpu(disk_super->blocknr),
206 (unsigned long long)dm_block_location(b));
207 return -ENOTBLK;
208 }
209
210 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
211 DMERR("sb_check failed: magic %llu: wanted %llu",
212 le64_to_cpu(disk_super->magic),
213 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
214 return -EILSEQ;
215 }
216
217 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
218 sb_block_size - sizeof(__le32),
219 SUPERBLOCK_CSUM_XOR));
220 if (csum_le != disk_super->csum) {
221 DMERR("sb_check failed: csum %u: wanted %u",
222 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
223 return -EILSEQ;
224 }
225
226 return check_metadata_version(disk_super);
227}
228
229static struct dm_block_validator sb_validator = {
230 .name = "superblock",
231 .prepare_for_write = sb_prepare_for_write,
232 .check = sb_check
233};
234
235/*----------------------------------------------------------------*/
236
237static int superblock_read_lock(struct dm_cache_metadata *cmd,
238 struct dm_block **sblock)
239{
240 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
241 &sb_validator, sblock);
242}
243
244static int superblock_lock_zero(struct dm_cache_metadata *cmd,
245 struct dm_block **sblock)
246{
247 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
248 &sb_validator, sblock);
249}
250
251static int superblock_lock(struct dm_cache_metadata *cmd,
252 struct dm_block **sblock)
253{
254 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
255 &sb_validator, sblock);
256}
257
258/*----------------------------------------------------------------*/
259
260static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
261{
262 int r;
263 unsigned i;
264 struct dm_block *b;
265 __le64 *data_le, zero = cpu_to_le64(0);
266 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
267
268 /*
269 * We can't use a validator here - it may be all zeroes.
270 */
271 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
272 if (r)
273 return r;
274
275 data_le = dm_block_data(b);
276 *result = true;
277 for (i = 0; i < sb_block_size; i++) {
278 if (data_le[i] != zero) {
279 *result = false;
280 break;
281 }
282 }
283
284 dm_bm_unlock(b);
285
286 return 0;
287}
288
289static void __setup_mapping_info(struct dm_cache_metadata *cmd)
290{
291 struct dm_btree_value_type vt;
292
293 vt.context = NULL;
294 vt.size = sizeof(__le64);
295 vt.inc = NULL;
296 vt.dec = NULL;
297 vt.equal = NULL;
298 dm_array_info_init(&cmd->info, cmd->tm, &vt);
299
300 if (cmd->policy_hint_size) {
301 vt.size = sizeof(__le32);
302 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
303 }
304}
305
306static int __save_sm_root(struct dm_cache_metadata *cmd)
307{
308 int r;
309 size_t metadata_len;
310
311 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
312 if (r < 0)
313 return r;
314
315 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
316 metadata_len);
317}
318
319static void __copy_sm_root(struct dm_cache_metadata *cmd,
320 struct cache_disk_superblock *disk_super)
321{
322 memcpy(&disk_super->metadata_space_map_root,
323 &cmd->metadata_space_map_root,
324 sizeof(cmd->metadata_space_map_root));
325}
326
327static bool separate_dirty_bits(struct dm_cache_metadata *cmd)
328{
329 return cmd->version >= 2;
330}
331
332static int __write_initial_superblock(struct dm_cache_metadata *cmd)
333{
334 int r;
335 struct dm_block *sblock;
336 struct cache_disk_superblock *disk_super;
337 sector_t bdev_size = bdev_nr_sectors(cmd->bdev);
338
339 /* FIXME: see if we can lose the max sectors limit */
340 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
341 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
342
343 r = dm_tm_pre_commit(cmd->tm);
344 if (r < 0)
345 return r;
346
347 /*
348 * dm_sm_copy_root() can fail. So we need to do it before we start
349 * updating the superblock.
350 */
351 r = __save_sm_root(cmd);
352 if (r)
353 return r;
354
355 r = superblock_lock_zero(cmd, &sblock);
356 if (r)
357 return r;
358
359 disk_super = dm_block_data(sblock);
360 disk_super->flags = 0;
361 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
362 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
363 disk_super->version = cpu_to_le32(cmd->version);
364 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
365 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
366 disk_super->policy_hint_size = cpu_to_le32(0);
367
368 __copy_sm_root(cmd, disk_super);
369
370 disk_super->mapping_root = cpu_to_le64(cmd->root);
371 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
372 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
373 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
374 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
375 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
376 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
377 disk_super->cache_blocks = cpu_to_le32(0);
378
379 disk_super->read_hits = cpu_to_le32(0);
380 disk_super->read_misses = cpu_to_le32(0);
381 disk_super->write_hits = cpu_to_le32(0);
382 disk_super->write_misses = cpu_to_le32(0);
383
384 if (separate_dirty_bits(cmd))
385 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
386
387 return dm_tm_commit(cmd->tm, sblock);
388}
389
390static int __format_metadata(struct dm_cache_metadata *cmd)
391{
392 int r;
393
394 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
395 &cmd->tm, &cmd->metadata_sm);
396 if (r < 0) {
397 DMERR("tm_create_with_sm failed");
398 return r;
399 }
400
401 __setup_mapping_info(cmd);
402
403 r = dm_array_empty(&cmd->info, &cmd->root);
404 if (r < 0)
405 goto bad;
406
407 if (separate_dirty_bits(cmd)) {
408 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
409 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root);
410 if (r < 0)
411 goto bad;
412 }
413
414 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
415 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
416 if (r < 0)
417 goto bad;
418
419 cmd->discard_block_size = 0;
420 cmd->discard_nr_blocks = 0;
421
422 r = __write_initial_superblock(cmd);
423 if (r)
424 goto bad;
425
426 cmd->clean_when_opened = true;
427 return 0;
428
429bad:
430 dm_tm_destroy(cmd->tm);
431 dm_sm_destroy(cmd->metadata_sm);
432
433 return r;
434}
435
436static int __check_incompat_features(struct cache_disk_superblock *disk_super,
437 struct dm_cache_metadata *cmd)
438{
439 uint32_t incompat_flags, features;
440
441 incompat_flags = le32_to_cpu(disk_super->incompat_flags);
442 features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
443 if (features) {
444 DMERR("could not access metadata due to unsupported optional features (%lx).",
445 (unsigned long)features);
446 return -EINVAL;
447 }
448
449 /*
450 * Check for read-only metadata to skip the following RDWR checks.
451 */
452 if (bdev_read_only(cmd->bdev))
453 return 0;
454
455 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
456 if (features) {
457 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
458 (unsigned long)features);
459 return -EINVAL;
460 }
461
462 return 0;
463}
464
465static int __open_metadata(struct dm_cache_metadata *cmd)
466{
467 int r;
468 struct dm_block *sblock;
469 struct cache_disk_superblock *disk_super;
470 unsigned long sb_flags;
471
472 r = superblock_read_lock(cmd, &sblock);
473 if (r < 0) {
474 DMERR("couldn't read lock superblock");
475 return r;
476 }
477
478 disk_super = dm_block_data(sblock);
479
480 /* Verify the data block size hasn't changed */
481 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
482 DMERR("changing the data block size (from %u to %llu) is not supported",
483 le32_to_cpu(disk_super->data_block_size),
484 (unsigned long long)cmd->data_block_size);
485 r = -EINVAL;
486 goto bad;
487 }
488
489 r = __check_incompat_features(disk_super, cmd);
490 if (r < 0)
491 goto bad;
492
493 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
494 disk_super->metadata_space_map_root,
495 sizeof(disk_super->metadata_space_map_root),
496 &cmd->tm, &cmd->metadata_sm);
497 if (r < 0) {
498 DMERR("tm_open_with_sm failed");
499 goto bad;
500 }
501
502 __setup_mapping_info(cmd);
503 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
504 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
505 sb_flags = le32_to_cpu(disk_super->flags);
506 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
507 dm_bm_unlock(sblock);
508
509 return 0;
510
511bad:
512 dm_bm_unlock(sblock);
513 return r;
514}
515
516static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
517 bool format_device)
518{
519 int r;
520 bool unformatted = false;
521
522 r = __superblock_all_zeroes(cmd->bm, &unformatted);
523 if (r)
524 return r;
525
526 if (unformatted)
527 return format_device ? __format_metadata(cmd) : -EPERM;
528
529 return __open_metadata(cmd);
530}
531
532static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
533 bool may_format_device)
534{
535 int r;
536 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
537 CACHE_MAX_CONCURRENT_LOCKS);
538 if (IS_ERR(cmd->bm)) {
539 DMERR("could not create block manager");
540 r = PTR_ERR(cmd->bm);
541 cmd->bm = NULL;
542 return r;
543 }
544
545 r = __open_or_format_metadata(cmd, may_format_device);
546 if (r) {
547 dm_block_manager_destroy(cmd->bm);
548 cmd->bm = NULL;
549 }
550
551 return r;
552}
553
554static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd,
555 bool destroy_bm)
556{
557 dm_sm_destroy(cmd->metadata_sm);
558 dm_tm_destroy(cmd->tm);
559 if (destroy_bm)
560 dm_block_manager_destroy(cmd->bm);
561}
562
563typedef unsigned long (*flags_mutator)(unsigned long);
564
565static void update_flags(struct cache_disk_superblock *disk_super,
566 flags_mutator mutator)
567{
568 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
569 disk_super->flags = cpu_to_le32(sb_flags);
570}
571
572static unsigned long set_clean_shutdown(unsigned long flags)
573{
574 set_bit(CLEAN_SHUTDOWN, &flags);
575 return flags;
576}
577
578static unsigned long clear_clean_shutdown(unsigned long flags)
579{
580 clear_bit(CLEAN_SHUTDOWN, &flags);
581 return flags;
582}
583
584static void read_superblock_fields(struct dm_cache_metadata *cmd,
585 struct cache_disk_superblock *disk_super)
586{
587 cmd->version = le32_to_cpu(disk_super->version);
588 cmd->flags = le32_to_cpu(disk_super->flags);
589 cmd->root = le64_to_cpu(disk_super->mapping_root);
590 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
591 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
592 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
593 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
594 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
595 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
596 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
597 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
598 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
599 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
600 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
601
602 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
603 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
604 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
605 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
606
607 if (separate_dirty_bits(cmd))
608 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
609
610 cmd->changed = false;
611}
612
613/*
614 * The mutator updates the superblock flags.
615 */
616static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
617 flags_mutator mutator)
618{
619 int r;
620 struct cache_disk_superblock *disk_super;
621 struct dm_block *sblock;
622
623 r = superblock_lock(cmd, &sblock);
624 if (r)
625 return r;
626
627 disk_super = dm_block_data(sblock);
628 update_flags(disk_super, mutator);
629 read_superblock_fields(cmd, disk_super);
630 dm_bm_unlock(sblock);
631
632 return dm_bm_flush(cmd->bm);
633}
634
635static int __begin_transaction(struct dm_cache_metadata *cmd)
636{
637 int r;
638 struct cache_disk_superblock *disk_super;
639 struct dm_block *sblock;
640
641 /*
642 * We re-read the superblock every time. Shouldn't need to do this
643 * really.
644 */
645 r = superblock_read_lock(cmd, &sblock);
646 if (r)
647 return r;
648
649 disk_super = dm_block_data(sblock);
650 read_superblock_fields(cmd, disk_super);
651 dm_bm_unlock(sblock);
652
653 return 0;
654}
655
656static int __commit_transaction(struct dm_cache_metadata *cmd,
657 flags_mutator mutator)
658{
659 int r;
660 struct cache_disk_superblock *disk_super;
661 struct dm_block *sblock;
662
663 /*
664 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
665 */
666 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
667
668 if (separate_dirty_bits(cmd)) {
669 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
670 &cmd->dirty_root);
671 if (r)
672 return r;
673 }
674
675 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
676 &cmd->discard_root);
677 if (r)
678 return r;
679
680 r = dm_tm_pre_commit(cmd->tm);
681 if (r < 0)
682 return r;
683
684 r = __save_sm_root(cmd);
685 if (r)
686 return r;
687
688 r = superblock_lock(cmd, &sblock);
689 if (r)
690 return r;
691
692 disk_super = dm_block_data(sblock);
693
694 disk_super->flags = cpu_to_le32(cmd->flags);
695 if (mutator)
696 update_flags(disk_super, mutator);
697
698 disk_super->mapping_root = cpu_to_le64(cmd->root);
699 if (separate_dirty_bits(cmd))
700 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
701 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
702 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
703 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
704 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
705 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
706 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
707 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
708 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
709 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
710 disk_super->policy_hint_size = cpu_to_le32(cmd->policy_hint_size);
711
712 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
713 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
714 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
715 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
716 __copy_sm_root(cmd, disk_super);
717
718 return dm_tm_commit(cmd->tm, sblock);
719}
720
721/*----------------------------------------------------------------*/
722
723/*
724 * The mappings are held in a dm-array that has 64-bit values stored in
725 * little-endian format. The index is the cblock, the high 48bits of the
726 * value are the oblock and the low 16 bit the flags.
727 */
728#define FLAGS_MASK ((1 << 16) - 1)
729
730static __le64 pack_value(dm_oblock_t block, unsigned flags)
731{
732 uint64_t value = from_oblock(block);
733 value <<= 16;
734 value = value | (flags & FLAGS_MASK);
735 return cpu_to_le64(value);
736}
737
738static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
739{
740 uint64_t value = le64_to_cpu(value_le);
741 uint64_t b = value >> 16;
742 *block = to_oblock(b);
743 *flags = value & FLAGS_MASK;
744}
745
746/*----------------------------------------------------------------*/
747
748static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
749 sector_t data_block_size,
750 bool may_format_device,
751 size_t policy_hint_size,
752 unsigned metadata_version)
753{
754 int r;
755 struct dm_cache_metadata *cmd;
756
757 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
758 if (!cmd) {
759 DMERR("could not allocate metadata struct");
760 return ERR_PTR(-ENOMEM);
761 }
762
763 cmd->version = metadata_version;
764 refcount_set(&cmd->ref_count, 1);
765 init_rwsem(&cmd->root_lock);
766 cmd->bdev = bdev;
767 cmd->data_block_size = data_block_size;
768 cmd->cache_blocks = 0;
769 cmd->policy_hint_size = policy_hint_size;
770 cmd->changed = true;
771 cmd->fail_io = false;
772
773 r = __create_persistent_data_objects(cmd, may_format_device);
774 if (r) {
775 kfree(cmd);
776 return ERR_PTR(r);
777 }
778
779 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
780 if (r < 0) {
781 dm_cache_metadata_close(cmd);
782 return ERR_PTR(r);
783 }
784
785 return cmd;
786}
787
788/*
789 * We keep a little list of ref counted metadata objects to prevent two
790 * different target instances creating separate bufio instances. This is
791 * an issue if a table is reloaded before the suspend.
792 */
793static DEFINE_MUTEX(table_lock);
794static LIST_HEAD(table);
795
796static struct dm_cache_metadata *lookup(struct block_device *bdev)
797{
798 struct dm_cache_metadata *cmd;
799
800 list_for_each_entry(cmd, &table, list)
801 if (cmd->bdev == bdev) {
802 refcount_inc(&cmd->ref_count);
803 return cmd;
804 }
805
806 return NULL;
807}
808
809static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
810 sector_t data_block_size,
811 bool may_format_device,
812 size_t policy_hint_size,
813 unsigned metadata_version)
814{
815 struct dm_cache_metadata *cmd, *cmd2;
816
817 mutex_lock(&table_lock);
818 cmd = lookup(bdev);
819 mutex_unlock(&table_lock);
820
821 if (cmd)
822 return cmd;
823
824 cmd = metadata_open(bdev, data_block_size, may_format_device,
825 policy_hint_size, metadata_version);
826 if (!IS_ERR(cmd)) {
827 mutex_lock(&table_lock);
828 cmd2 = lookup(bdev);
829 if (cmd2) {
830 mutex_unlock(&table_lock);
831 __destroy_persistent_data_objects(cmd, true);
832 kfree(cmd);
833 return cmd2;
834 }
835 list_add(&cmd->list, &table);
836 mutex_unlock(&table_lock);
837 }
838
839 return cmd;
840}
841
842static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
843{
844 if (cmd->data_block_size != data_block_size) {
845 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
846 (unsigned long long) data_block_size,
847 (unsigned long long) cmd->data_block_size);
848 return false;
849 }
850
851 return true;
852}
853
854struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
855 sector_t data_block_size,
856 bool may_format_device,
857 size_t policy_hint_size,
858 unsigned metadata_version)
859{
860 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
861 policy_hint_size, metadata_version);
862
863 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
864 dm_cache_metadata_close(cmd);
865 return ERR_PTR(-EINVAL);
866 }
867
868 return cmd;
869}
870
871void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
872{
873 if (refcount_dec_and_test(&cmd->ref_count)) {
874 mutex_lock(&table_lock);
875 list_del(&cmd->list);
876 mutex_unlock(&table_lock);
877
878 if (!cmd->fail_io)
879 __destroy_persistent_data_objects(cmd, true);
880 kfree(cmd);
881 }
882}
883
884/*
885 * Checks that the given cache block is either unmapped or clean.
886 */
887static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
888 bool *result)
889{
890 int r;
891 __le64 value;
892 dm_oblock_t ob;
893 unsigned flags;
894
895 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
896 if (r)
897 return r;
898
899 unpack_value(value, &ob, &flags);
900 *result = !((flags & M_VALID) && (flags & M_DIRTY));
901
902 return 0;
903}
904
905static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
906 dm_cblock_t begin, dm_cblock_t end,
907 bool *result)
908{
909 int r;
910 *result = true;
911
912 while (begin != end) {
913 r = block_clean_combined_dirty(cmd, begin, result);
914 if (r) {
915 DMERR("block_clean_combined_dirty failed");
916 return r;
917 }
918
919 if (!*result) {
920 DMERR("cache block %llu is dirty",
921 (unsigned long long) from_cblock(begin));
922 return 0;
923 }
924
925 begin = to_cblock(from_cblock(begin) + 1);
926 }
927
928 return 0;
929}
930
931static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
932 dm_cblock_t begin, dm_cblock_t end,
933 bool *result)
934{
935 int r;
936 bool dirty_flag;
937 *result = true;
938
939 if (from_cblock(cmd->cache_blocks) == 0)
940 /* Nothing to do */
941 return 0;
942
943 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
944 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
945 if (r) {
946 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__);
947 return r;
948 }
949
950 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin));
951 if (r) {
952 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
953 dm_bitset_cursor_end(&cmd->dirty_cursor);
954 return r;
955 }
956
957 while (begin != end) {
958 /*
959 * We assume that unmapped blocks have their dirty bit
960 * cleared.
961 */
962 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor);
963 if (dirty_flag) {
964 DMERR("%s: cache block %llu is dirty", __func__,
965 (unsigned long long) from_cblock(begin));
966 dm_bitset_cursor_end(&cmd->dirty_cursor);
967 *result = false;
968 return 0;
969 }
970
971 begin = to_cblock(from_cblock(begin) + 1);
972 if (begin == end)
973 break;
974
975 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
976 if (r) {
977 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
978 dm_bitset_cursor_end(&cmd->dirty_cursor);
979 return r;
980 }
981 }
982
983 dm_bitset_cursor_end(&cmd->dirty_cursor);
984
985 return 0;
986}
987
988static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
989 dm_cblock_t begin, dm_cblock_t end,
990 bool *result)
991{
992 if (separate_dirty_bits(cmd))
993 return blocks_are_clean_separate_dirty(cmd, begin, end, result);
994 else
995 return blocks_are_clean_combined_dirty(cmd, begin, end, result);
996}
997
998static bool cmd_write_lock(struct dm_cache_metadata *cmd)
999{
1000 down_write(&cmd->root_lock);
1001 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
1002 up_write(&cmd->root_lock);
1003 return false;
1004 }
1005 return true;
1006}
1007
1008#define WRITE_LOCK(cmd) \
1009 do { \
1010 if (!cmd_write_lock((cmd))) \
1011 return -EINVAL; \
1012 } while(0)
1013
1014#define WRITE_LOCK_VOID(cmd) \
1015 do { \
1016 if (!cmd_write_lock((cmd))) \
1017 return; \
1018 } while(0)
1019
1020#define WRITE_UNLOCK(cmd) \
1021 up_write(&(cmd)->root_lock)
1022
1023static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1024{
1025 down_read(&cmd->root_lock);
1026 if (cmd->fail_io) {
1027 up_read(&cmd->root_lock);
1028 return false;
1029 }
1030 return true;
1031}
1032
1033#define READ_LOCK(cmd) \
1034 do { \
1035 if (!cmd_read_lock((cmd))) \
1036 return -EINVAL; \
1037 } while(0)
1038
1039#define READ_LOCK_VOID(cmd) \
1040 do { \
1041 if (!cmd_read_lock((cmd))) \
1042 return; \
1043 } while(0)
1044
1045#define READ_UNLOCK(cmd) \
1046 up_read(&(cmd)->root_lock)
1047
1048int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1049{
1050 int r;
1051 bool clean;
1052 __le64 null_mapping = pack_value(0, 0);
1053
1054 WRITE_LOCK(cmd);
1055 __dm_bless_for_disk(&null_mapping);
1056
1057 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1058 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
1059 if (r) {
1060 __dm_unbless_for_disk(&null_mapping);
1061 goto out;
1062 }
1063
1064 if (!clean) {
1065 DMERR("unable to shrink cache due to dirty blocks");
1066 r = -EINVAL;
1067 __dm_unbless_for_disk(&null_mapping);
1068 goto out;
1069 }
1070 }
1071
1072 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1073 from_cblock(new_cache_size),
1074 &null_mapping, &cmd->root);
1075 if (r)
1076 goto out;
1077
1078 if (separate_dirty_bits(cmd)) {
1079 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1080 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1081 false, &cmd->dirty_root);
1082 if (r)
1083 goto out;
1084 }
1085
1086 cmd->cache_blocks = new_cache_size;
1087 cmd->changed = true;
1088
1089out:
1090 WRITE_UNLOCK(cmd);
1091
1092 return r;
1093}
1094
1095int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1096 sector_t discard_block_size,
1097 dm_dblock_t new_nr_entries)
1098{
1099 int r;
1100
1101 WRITE_LOCK(cmd);
1102 r = dm_bitset_resize(&cmd->discard_info,
1103 cmd->discard_root,
1104 from_dblock(cmd->discard_nr_blocks),
1105 from_dblock(new_nr_entries),
1106 false, &cmd->discard_root);
1107 if (!r) {
1108 cmd->discard_block_size = discard_block_size;
1109 cmd->discard_nr_blocks = new_nr_entries;
1110 }
1111
1112 cmd->changed = true;
1113 WRITE_UNLOCK(cmd);
1114
1115 return r;
1116}
1117
1118static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1119{
1120 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
1121 from_dblock(b), &cmd->discard_root);
1122}
1123
1124static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1125{
1126 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
1127 from_dblock(b), &cmd->discard_root);
1128}
1129
1130static int __discard(struct dm_cache_metadata *cmd,
1131 dm_dblock_t dblock, bool discard)
1132{
1133 int r;
1134
1135 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1136 if (r)
1137 return r;
1138
1139 cmd->changed = true;
1140 return 0;
1141}
1142
1143int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1144 dm_dblock_t dblock, bool discard)
1145{
1146 int r;
1147
1148 WRITE_LOCK(cmd);
1149 r = __discard(cmd, dblock, discard);
1150 WRITE_UNLOCK(cmd);
1151
1152 return r;
1153}
1154
1155static int __load_discards(struct dm_cache_metadata *cmd,
1156 load_discard_fn fn, void *context)
1157{
1158 int r = 0;
1159 uint32_t b;
1160 struct dm_bitset_cursor c;
1161
1162 if (from_dblock(cmd->discard_nr_blocks) == 0)
1163 /* nothing to do */
1164 return 0;
1165
1166 if (cmd->clean_when_opened) {
1167 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1168 if (r)
1169 return r;
1170
1171 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1172 from_dblock(cmd->discard_nr_blocks), &c);
1173 if (r)
1174 return r;
1175
1176 for (b = 0; ; b++) {
1177 r = fn(context, cmd->discard_block_size, to_dblock(b),
1178 dm_bitset_cursor_get_value(&c));
1179 if (r)
1180 break;
1181
1182 if (b >= (from_dblock(cmd->discard_nr_blocks) - 1))
1183 break;
1184
1185 r = dm_bitset_cursor_next(&c);
1186 if (r)
1187 break;
1188 }
1189
1190 dm_bitset_cursor_end(&c);
1191
1192 } else {
1193 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1194 r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1195 if (r)
1196 return r;
1197 }
1198 }
1199
1200 return r;
1201}
1202
1203int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1204 load_discard_fn fn, void *context)
1205{
1206 int r;
1207
1208 READ_LOCK(cmd);
1209 r = __load_discards(cmd, fn, context);
1210 READ_UNLOCK(cmd);
1211
1212 return r;
1213}
1214
1215int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1216{
1217 READ_LOCK(cmd);
1218 *result = cmd->cache_blocks;
1219 READ_UNLOCK(cmd);
1220
1221 return 0;
1222}
1223
1224static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1225{
1226 int r;
1227 __le64 value = pack_value(0, 0);
1228
1229 __dm_bless_for_disk(&value);
1230 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1231 &value, &cmd->root);
1232 if (r)
1233 return r;
1234
1235 cmd->changed = true;
1236 return 0;
1237}
1238
1239int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1240{
1241 int r;
1242
1243 WRITE_LOCK(cmd);
1244 r = __remove(cmd, cblock);
1245 WRITE_UNLOCK(cmd);
1246
1247 return r;
1248}
1249
1250static int __insert(struct dm_cache_metadata *cmd,
1251 dm_cblock_t cblock, dm_oblock_t oblock)
1252{
1253 int r;
1254 __le64 value = pack_value(oblock, M_VALID);
1255 __dm_bless_for_disk(&value);
1256
1257 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1258 &value, &cmd->root);
1259 if (r)
1260 return r;
1261
1262 cmd->changed = true;
1263 return 0;
1264}
1265
1266int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1267 dm_cblock_t cblock, dm_oblock_t oblock)
1268{
1269 int r;
1270
1271 WRITE_LOCK(cmd);
1272 r = __insert(cmd, cblock, oblock);
1273 WRITE_UNLOCK(cmd);
1274
1275 return r;
1276}
1277
1278struct thunk {
1279 load_mapping_fn fn;
1280 void *context;
1281
1282 struct dm_cache_metadata *cmd;
1283 bool respect_dirty_flags;
1284 bool hints_valid;
1285};
1286
1287static bool policy_unchanged(struct dm_cache_metadata *cmd,
1288 struct dm_cache_policy *policy)
1289{
1290 const char *policy_name = dm_cache_policy_get_name(policy);
1291 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1292 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1293
1294 /*
1295 * Ensure policy names match.
1296 */
1297 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1298 return false;
1299
1300 /*
1301 * Ensure policy major versions match.
1302 */
1303 if (cmd->policy_version[0] != policy_version[0])
1304 return false;
1305
1306 /*
1307 * Ensure policy hint sizes match.
1308 */
1309 if (cmd->policy_hint_size != policy_hint_size)
1310 return false;
1311
1312 return true;
1313}
1314
1315static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1316{
1317 return cmd->hint_root && cmd->policy_hint_size;
1318}
1319
1320static bool hints_array_available(struct dm_cache_metadata *cmd,
1321 struct dm_cache_policy *policy)
1322{
1323 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1324 hints_array_initialized(cmd);
1325}
1326
1327static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1328 uint64_t cb, bool hints_valid,
1329 struct dm_array_cursor *mapping_cursor,
1330 struct dm_array_cursor *hint_cursor,
1331 load_mapping_fn fn, void *context)
1332{
1333 int r = 0;
1334
1335 __le64 mapping;
1336 __le32 hint = 0;
1337
1338 __le64 *mapping_value_le;
1339 __le32 *hint_value_le;
1340
1341 dm_oblock_t oblock;
1342 unsigned flags;
1343 bool dirty = true;
1344
1345 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1346 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1347 unpack_value(mapping, &oblock, &flags);
1348
1349 if (flags & M_VALID) {
1350 if (hints_valid) {
1351 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1352 memcpy(&hint, hint_value_le, sizeof(hint));
1353 }
1354 if (cmd->clean_when_opened)
1355 dirty = flags & M_DIRTY;
1356
1357 r = fn(context, oblock, to_cblock(cb), dirty,
1358 le32_to_cpu(hint), hints_valid);
1359 if (r) {
1360 DMERR("policy couldn't load cache block %llu",
1361 (unsigned long long) from_cblock(to_cblock(cb)));
1362 }
1363 }
1364
1365 return r;
1366}
1367
1368static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1369 uint64_t cb, bool hints_valid,
1370 struct dm_array_cursor *mapping_cursor,
1371 struct dm_array_cursor *hint_cursor,
1372 struct dm_bitset_cursor *dirty_cursor,
1373 load_mapping_fn fn, void *context)
1374{
1375 int r = 0;
1376
1377 __le64 mapping;
1378 __le32 hint = 0;
1379
1380 __le64 *mapping_value_le;
1381 __le32 *hint_value_le;
1382
1383 dm_oblock_t oblock;
1384 unsigned flags;
1385 bool dirty = true;
1386
1387 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1388 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1389 unpack_value(mapping, &oblock, &flags);
1390
1391 if (flags & M_VALID) {
1392 if (hints_valid) {
1393 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1394 memcpy(&hint, hint_value_le, sizeof(hint));
1395 }
1396 if (cmd->clean_when_opened)
1397 dirty = dm_bitset_cursor_get_value(dirty_cursor);
1398
1399 r = fn(context, oblock, to_cblock(cb), dirty,
1400 le32_to_cpu(hint), hints_valid);
1401 if (r) {
1402 DMERR("policy couldn't load cache block %llu",
1403 (unsigned long long) from_cblock(to_cblock(cb)));
1404 }
1405 }
1406
1407 return r;
1408}
1409
1410static int __load_mappings(struct dm_cache_metadata *cmd,
1411 struct dm_cache_policy *policy,
1412 load_mapping_fn fn, void *context)
1413{
1414 int r;
1415 uint64_t cb;
1416
1417 bool hints_valid = hints_array_available(cmd, policy);
1418
1419 if (from_cblock(cmd->cache_blocks) == 0)
1420 /* Nothing to do */
1421 return 0;
1422
1423 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1424 if (r)
1425 return r;
1426
1427 if (hints_valid) {
1428 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1429 if (r) {
1430 dm_array_cursor_end(&cmd->mapping_cursor);
1431 return r;
1432 }
1433 }
1434
1435 if (separate_dirty_bits(cmd)) {
1436 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1437 from_cblock(cmd->cache_blocks),
1438 &cmd->dirty_cursor);
1439 if (r) {
1440 dm_array_cursor_end(&cmd->hint_cursor);
1441 dm_array_cursor_end(&cmd->mapping_cursor);
1442 return r;
1443 }
1444 }
1445
1446 for (cb = 0; ; cb++) {
1447 if (separate_dirty_bits(cmd))
1448 r = __load_mapping_v2(cmd, cb, hints_valid,
1449 &cmd->mapping_cursor,
1450 &cmd->hint_cursor,
1451 &cmd->dirty_cursor,
1452 fn, context);
1453 else
1454 r = __load_mapping_v1(cmd, cb, hints_valid,
1455 &cmd->mapping_cursor, &cmd->hint_cursor,
1456 fn, context);
1457 if (r)
1458 goto out;
1459
1460 /*
1461 * We need to break out before we move the cursors.
1462 */
1463 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1464 break;
1465
1466 r = dm_array_cursor_next(&cmd->mapping_cursor);
1467 if (r) {
1468 DMERR("dm_array_cursor_next for mapping failed");
1469 goto out;
1470 }
1471
1472 if (hints_valid) {
1473 r = dm_array_cursor_next(&cmd->hint_cursor);
1474 if (r) {
1475 dm_array_cursor_end(&cmd->hint_cursor);
1476 hints_valid = false;
1477 }
1478 }
1479
1480 if (separate_dirty_bits(cmd)) {
1481 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1482 if (r) {
1483 DMERR("dm_bitset_cursor_next for dirty failed");
1484 goto out;
1485 }
1486 }
1487 }
1488out:
1489 dm_array_cursor_end(&cmd->mapping_cursor);
1490 if (hints_valid)
1491 dm_array_cursor_end(&cmd->hint_cursor);
1492
1493 if (separate_dirty_bits(cmd))
1494 dm_bitset_cursor_end(&cmd->dirty_cursor);
1495
1496 return r;
1497}
1498
1499int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1500 struct dm_cache_policy *policy,
1501 load_mapping_fn fn, void *context)
1502{
1503 int r;
1504
1505 READ_LOCK(cmd);
1506 r = __load_mappings(cmd, policy, fn, context);
1507 READ_UNLOCK(cmd);
1508
1509 return r;
1510}
1511
1512static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1513{
1514 __le64 value;
1515 dm_oblock_t oblock;
1516 unsigned flags;
1517
1518 memcpy(&value, leaf, sizeof(value));
1519 unpack_value(value, &oblock, &flags);
1520
1521 return 0;
1522}
1523
1524static int __dump_mappings(struct dm_cache_metadata *cmd)
1525{
1526 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1527}
1528
1529void dm_cache_dump(struct dm_cache_metadata *cmd)
1530{
1531 READ_LOCK_VOID(cmd);
1532 __dump_mappings(cmd);
1533 READ_UNLOCK(cmd);
1534}
1535
1536int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1537{
1538 int r;
1539
1540 READ_LOCK(cmd);
1541 r = cmd->changed;
1542 READ_UNLOCK(cmd);
1543
1544 return r;
1545}
1546
1547static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1548{
1549 int r;
1550 unsigned flags;
1551 dm_oblock_t oblock;
1552 __le64 value;
1553
1554 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1555 if (r)
1556 return r;
1557
1558 unpack_value(value, &oblock, &flags);
1559
1560 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1561 /* nothing to be done */
1562 return 0;
1563
1564 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1565 __dm_bless_for_disk(&value);
1566
1567 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1568 &value, &cmd->root);
1569 if (r)
1570 return r;
1571
1572 cmd->changed = true;
1573 return 0;
1574
1575}
1576
1577static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1578{
1579 int r;
1580 unsigned i;
1581 for (i = 0; i < nr_bits; i++) {
1582 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1583 if (r)
1584 return r;
1585 }
1586
1587 return 0;
1588}
1589
1590static int is_dirty_callback(uint32_t index, bool *value, void *context)
1591{
1592 unsigned long *bits = context;
1593 *value = test_bit(index, bits);
1594 return 0;
1595}
1596
1597static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1598{
1599 int r = 0;
1600
1601 /* nr_bits is really just a sanity check */
1602 if (nr_bits != from_cblock(cmd->cache_blocks)) {
1603 DMERR("dirty bitset is wrong size");
1604 return -EINVAL;
1605 }
1606
1607 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1608 if (r)
1609 return r;
1610
1611 cmd->changed = true;
1612 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1613}
1614
1615int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1616 unsigned nr_bits,
1617 unsigned long *bits)
1618{
1619 int r;
1620
1621 WRITE_LOCK(cmd);
1622 if (separate_dirty_bits(cmd))
1623 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1624 else
1625 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1626 WRITE_UNLOCK(cmd);
1627
1628 return r;
1629}
1630
1631void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1632 struct dm_cache_statistics *stats)
1633{
1634 READ_LOCK_VOID(cmd);
1635 *stats = cmd->stats;
1636 READ_UNLOCK(cmd);
1637}
1638
1639void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1640 struct dm_cache_statistics *stats)
1641{
1642 WRITE_LOCK_VOID(cmd);
1643 cmd->stats = *stats;
1644 WRITE_UNLOCK(cmd);
1645}
1646
1647int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1648{
1649 int r = -EINVAL;
1650 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1651 clear_clean_shutdown);
1652
1653 WRITE_LOCK(cmd);
1654 if (cmd->fail_io)
1655 goto out;
1656
1657 r = __commit_transaction(cmd, mutator);
1658 if (r)
1659 goto out;
1660
1661 r = __begin_transaction(cmd);
1662out:
1663 WRITE_UNLOCK(cmd);
1664 return r;
1665}
1666
1667int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1668 dm_block_t *result)
1669{
1670 int r = -EINVAL;
1671
1672 READ_LOCK(cmd);
1673 if (!cmd->fail_io)
1674 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1675 READ_UNLOCK(cmd);
1676
1677 return r;
1678}
1679
1680int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1681 dm_block_t *result)
1682{
1683 int r = -EINVAL;
1684
1685 READ_LOCK(cmd);
1686 if (!cmd->fail_io)
1687 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1688 READ_UNLOCK(cmd);
1689
1690 return r;
1691}
1692
1693/*----------------------------------------------------------------*/
1694
1695static int get_hint(uint32_t index, void *value_le, void *context)
1696{
1697 uint32_t value;
1698 struct dm_cache_policy *policy = context;
1699
1700 value = policy_get_hint(policy, to_cblock(index));
1701 *((__le32 *) value_le) = cpu_to_le32(value);
1702
1703 return 0;
1704}
1705
1706/*
1707 * It's quicker to always delete the hint array, and recreate with
1708 * dm_array_new().
1709 */
1710static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1711{
1712 int r;
1713 size_t hint_size;
1714 const char *policy_name = dm_cache_policy_get_name(policy);
1715 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1716
1717 if (!policy_name[0] ||
1718 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1719 return -EINVAL;
1720
1721 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1722 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1723
1724 hint_size = dm_cache_policy_get_hint_size(policy);
1725 if (!hint_size)
1726 return 0; /* short-circuit hints initialization */
1727 cmd->policy_hint_size = hint_size;
1728
1729 if (cmd->hint_root) {
1730 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1731 if (r)
1732 return r;
1733 }
1734
1735 return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1736 from_cblock(cmd->cache_blocks),
1737 get_hint, policy);
1738}
1739
1740int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1741{
1742 int r;
1743
1744 WRITE_LOCK(cmd);
1745 r = write_hints(cmd, policy);
1746 WRITE_UNLOCK(cmd);
1747
1748 return r;
1749}
1750
1751int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1752{
1753 int r;
1754
1755 READ_LOCK(cmd);
1756 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1757 READ_UNLOCK(cmd);
1758
1759 return r;
1760}
1761
1762void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1763{
1764 WRITE_LOCK_VOID(cmd);
1765 dm_bm_set_read_only(cmd->bm);
1766 WRITE_UNLOCK(cmd);
1767}
1768
1769void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1770{
1771 WRITE_LOCK_VOID(cmd);
1772 dm_bm_set_read_write(cmd->bm);
1773 WRITE_UNLOCK(cmd);
1774}
1775
1776int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1777{
1778 int r;
1779 struct dm_block *sblock;
1780 struct cache_disk_superblock *disk_super;
1781
1782 WRITE_LOCK(cmd);
1783 set_bit(NEEDS_CHECK, &cmd->flags);
1784
1785 r = superblock_lock(cmd, &sblock);
1786 if (r) {
1787 DMERR("couldn't read superblock");
1788 goto out;
1789 }
1790
1791 disk_super = dm_block_data(sblock);
1792 disk_super->flags = cpu_to_le32(cmd->flags);
1793
1794 dm_bm_unlock(sblock);
1795
1796out:
1797 WRITE_UNLOCK(cmd);
1798 return r;
1799}
1800
1801int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1802{
1803 READ_LOCK(cmd);
1804 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1805 READ_UNLOCK(cmd);
1806
1807 return 0;
1808}
1809
1810int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1811{
1812 int r = -EINVAL;
1813 struct dm_block_manager *old_bm = NULL, *new_bm = NULL;
1814
1815 /* fail_io is double-checked with cmd->root_lock held below */
1816 if (unlikely(cmd->fail_io))
1817 return r;
1818
1819 /*
1820 * Replacement block manager (new_bm) is created and old_bm destroyed outside of
1821 * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
1822 * shrinker associated with the block manager's bufio client vs cmd root_lock).
1823 * - must take shrinker_rwsem without holding cmd->root_lock
1824 */
1825 new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
1826 CACHE_MAX_CONCURRENT_LOCKS);
1827
1828 WRITE_LOCK(cmd);
1829 if (cmd->fail_io) {
1830 WRITE_UNLOCK(cmd);
1831 goto out;
1832 }
1833
1834 __destroy_persistent_data_objects(cmd, false);
1835 old_bm = cmd->bm;
1836 if (IS_ERR(new_bm)) {
1837 DMERR("could not create block manager during abort");
1838 cmd->bm = NULL;
1839 r = PTR_ERR(new_bm);
1840 goto out_unlock;
1841 }
1842
1843 cmd->bm = new_bm;
1844 r = __open_or_format_metadata(cmd, false);
1845 if (r) {
1846 cmd->bm = NULL;
1847 goto out_unlock;
1848 }
1849 new_bm = NULL;
1850out_unlock:
1851 if (r)
1852 cmd->fail_io = true;
1853 WRITE_UNLOCK(cmd);
1854 dm_block_manager_destroy(old_bm);
1855out:
1856 if (new_bm && !IS_ERR(new_bm))
1857 dm_block_manager_destroy(new_bm);
1858
1859 return r;
1860}