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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 = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
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 (get_disk_ro(cmd->bdev->bd_disk))
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{
556 dm_sm_destroy(cmd->metadata_sm);
557 dm_tm_destroy(cmd->tm);
558 dm_block_manager_destroy(cmd->bm);
559}
560
561typedef unsigned long (*flags_mutator)(unsigned long);
562
563static void update_flags(struct cache_disk_superblock *disk_super,
564 flags_mutator mutator)
565{
566 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
567 disk_super->flags = cpu_to_le32(sb_flags);
568}
569
570static unsigned long set_clean_shutdown(unsigned long flags)
571{
572 set_bit(CLEAN_SHUTDOWN, &flags);
573 return flags;
574}
575
576static unsigned long clear_clean_shutdown(unsigned long flags)
577{
578 clear_bit(CLEAN_SHUTDOWN, &flags);
579 return flags;
580}
581
582static void read_superblock_fields(struct dm_cache_metadata *cmd,
583 struct cache_disk_superblock *disk_super)
584{
585 cmd->version = le32_to_cpu(disk_super->version);
586 cmd->flags = le32_to_cpu(disk_super->flags);
587 cmd->root = le64_to_cpu(disk_super->mapping_root);
588 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
589 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
590 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
591 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
592 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
593 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
594 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
595 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
596 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
597 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
598 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
599
600 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
601 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
602 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
603 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
604
605 if (separate_dirty_bits(cmd))
606 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
607
608 cmd->changed = false;
609}
610
611/*
612 * The mutator updates the superblock flags.
613 */
614static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
615 flags_mutator mutator)
616{
617 int r;
618 struct cache_disk_superblock *disk_super;
619 struct dm_block *sblock;
620
621 r = superblock_lock(cmd, &sblock);
622 if (r)
623 return r;
624
625 disk_super = dm_block_data(sblock);
626 update_flags(disk_super, mutator);
627 read_superblock_fields(cmd, disk_super);
628 dm_bm_unlock(sblock);
629
630 return dm_bm_flush(cmd->bm);
631}
632
633static int __begin_transaction(struct dm_cache_metadata *cmd)
634{
635 int r;
636 struct cache_disk_superblock *disk_super;
637 struct dm_block *sblock;
638
639 /*
640 * We re-read the superblock every time. Shouldn't need to do this
641 * really.
642 */
643 r = superblock_read_lock(cmd, &sblock);
644 if (r)
645 return r;
646
647 disk_super = dm_block_data(sblock);
648 read_superblock_fields(cmd, disk_super);
649 dm_bm_unlock(sblock);
650
651 return 0;
652}
653
654static int __commit_transaction(struct dm_cache_metadata *cmd,
655 flags_mutator mutator)
656{
657 int r;
658 struct cache_disk_superblock *disk_super;
659 struct dm_block *sblock;
660
661 /*
662 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
663 */
664 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
665
666 if (separate_dirty_bits(cmd)) {
667 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
668 &cmd->dirty_root);
669 if (r)
670 return r;
671 }
672
673 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
674 &cmd->discard_root);
675 if (r)
676 return r;
677
678 r = dm_tm_pre_commit(cmd->tm);
679 if (r < 0)
680 return r;
681
682 r = __save_sm_root(cmd);
683 if (r)
684 return r;
685
686 r = superblock_lock(cmd, &sblock);
687 if (r)
688 return r;
689
690 disk_super = dm_block_data(sblock);
691
692 disk_super->flags = cpu_to_le32(cmd->flags);
693 if (mutator)
694 update_flags(disk_super, mutator);
695
696 disk_super->mapping_root = cpu_to_le64(cmd->root);
697 if (separate_dirty_bits(cmd))
698 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
699 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
700 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
701 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
702 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
703 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
704 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
705 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
706 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
707 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
708 disk_super->policy_hint_size = cpu_to_le32(cmd->policy_hint_size);
709
710 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
711 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
712 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
713 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
714 __copy_sm_root(cmd, disk_super);
715
716 return dm_tm_commit(cmd->tm, sblock);
717}
718
719/*----------------------------------------------------------------*/
720
721/*
722 * The mappings are held in a dm-array that has 64-bit values stored in
723 * little-endian format. The index is the cblock, the high 48bits of the
724 * value are the oblock and the low 16 bit the flags.
725 */
726#define FLAGS_MASK ((1 << 16) - 1)
727
728static __le64 pack_value(dm_oblock_t block, unsigned flags)
729{
730 uint64_t value = from_oblock(block);
731 value <<= 16;
732 value = value | (flags & FLAGS_MASK);
733 return cpu_to_le64(value);
734}
735
736static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
737{
738 uint64_t value = le64_to_cpu(value_le);
739 uint64_t b = value >> 16;
740 *block = to_oblock(b);
741 *flags = value & FLAGS_MASK;
742}
743
744/*----------------------------------------------------------------*/
745
746static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
747 sector_t data_block_size,
748 bool may_format_device,
749 size_t policy_hint_size,
750 unsigned metadata_version)
751{
752 int r;
753 struct dm_cache_metadata *cmd;
754
755 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
756 if (!cmd) {
757 DMERR("could not allocate metadata struct");
758 return ERR_PTR(-ENOMEM);
759 }
760
761 cmd->version = metadata_version;
762 refcount_set(&cmd->ref_count, 1);
763 init_rwsem(&cmd->root_lock);
764 cmd->bdev = bdev;
765 cmd->data_block_size = data_block_size;
766 cmd->cache_blocks = 0;
767 cmd->policy_hint_size = policy_hint_size;
768 cmd->changed = true;
769 cmd->fail_io = false;
770
771 r = __create_persistent_data_objects(cmd, may_format_device);
772 if (r) {
773 kfree(cmd);
774 return ERR_PTR(r);
775 }
776
777 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
778 if (r < 0) {
779 dm_cache_metadata_close(cmd);
780 return ERR_PTR(r);
781 }
782
783 return cmd;
784}
785
786/*
787 * We keep a little list of ref counted metadata objects to prevent two
788 * different target instances creating separate bufio instances. This is
789 * an issue if a table is reloaded before the suspend.
790 */
791static DEFINE_MUTEX(table_lock);
792static LIST_HEAD(table);
793
794static struct dm_cache_metadata *lookup(struct block_device *bdev)
795{
796 struct dm_cache_metadata *cmd;
797
798 list_for_each_entry(cmd, &table, list)
799 if (cmd->bdev == bdev) {
800 refcount_inc(&cmd->ref_count);
801 return cmd;
802 }
803
804 return NULL;
805}
806
807static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
808 sector_t data_block_size,
809 bool may_format_device,
810 size_t policy_hint_size,
811 unsigned metadata_version)
812{
813 struct dm_cache_metadata *cmd, *cmd2;
814
815 mutex_lock(&table_lock);
816 cmd = lookup(bdev);
817 mutex_unlock(&table_lock);
818
819 if (cmd)
820 return cmd;
821
822 cmd = metadata_open(bdev, data_block_size, may_format_device,
823 policy_hint_size, metadata_version);
824 if (!IS_ERR(cmd)) {
825 mutex_lock(&table_lock);
826 cmd2 = lookup(bdev);
827 if (cmd2) {
828 mutex_unlock(&table_lock);
829 __destroy_persistent_data_objects(cmd);
830 kfree(cmd);
831 return cmd2;
832 }
833 list_add(&cmd->list, &table);
834 mutex_unlock(&table_lock);
835 }
836
837 return cmd;
838}
839
840static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
841{
842 if (cmd->data_block_size != data_block_size) {
843 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
844 (unsigned long long) data_block_size,
845 (unsigned long long) cmd->data_block_size);
846 return false;
847 }
848
849 return true;
850}
851
852struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
853 sector_t data_block_size,
854 bool may_format_device,
855 size_t policy_hint_size,
856 unsigned metadata_version)
857{
858 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
859 policy_hint_size, metadata_version);
860
861 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
862 dm_cache_metadata_close(cmd);
863 return ERR_PTR(-EINVAL);
864 }
865
866 return cmd;
867}
868
869void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
870{
871 if (refcount_dec_and_test(&cmd->ref_count)) {
872 mutex_lock(&table_lock);
873 list_del(&cmd->list);
874 mutex_unlock(&table_lock);
875
876 if (!cmd->fail_io)
877 __destroy_persistent_data_objects(cmd);
878 kfree(cmd);
879 }
880}
881
882/*
883 * Checks that the given cache block is either unmapped or clean.
884 */
885static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
886 bool *result)
887{
888 int r;
889 __le64 value;
890 dm_oblock_t ob;
891 unsigned flags;
892
893 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
894 if (r)
895 return r;
896
897 unpack_value(value, &ob, &flags);
898 *result = !((flags & M_VALID) && (flags & M_DIRTY));
899
900 return 0;
901}
902
903static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
904 dm_cblock_t begin, dm_cblock_t end,
905 bool *result)
906{
907 int r;
908 *result = true;
909
910 while (begin != end) {
911 r = block_clean_combined_dirty(cmd, begin, result);
912 if (r) {
913 DMERR("block_clean_combined_dirty failed");
914 return r;
915 }
916
917 if (!*result) {
918 DMERR("cache block %llu is dirty",
919 (unsigned long long) from_cblock(begin));
920 return 0;
921 }
922
923 begin = to_cblock(from_cblock(begin) + 1);
924 }
925
926 return 0;
927}
928
929static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
930 dm_cblock_t begin, dm_cblock_t end,
931 bool *result)
932{
933 int r;
934 bool dirty_flag;
935 *result = true;
936
937 if (from_cblock(cmd->cache_blocks) == 0)
938 /* Nothing to do */
939 return 0;
940
941 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
942 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
943 if (r) {
944 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__);
945 return r;
946 }
947
948 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin));
949 if (r) {
950 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
951 dm_bitset_cursor_end(&cmd->dirty_cursor);
952 return r;
953 }
954
955 while (begin != end) {
956 /*
957 * We assume that unmapped blocks have their dirty bit
958 * cleared.
959 */
960 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor);
961 if (dirty_flag) {
962 DMERR("%s: cache block %llu is dirty", __func__,
963 (unsigned long long) from_cblock(begin));
964 dm_bitset_cursor_end(&cmd->dirty_cursor);
965 *result = false;
966 return 0;
967 }
968
969 begin = to_cblock(from_cblock(begin) + 1);
970 if (begin == end)
971 break;
972
973 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
974 if (r) {
975 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
976 dm_bitset_cursor_end(&cmd->dirty_cursor);
977 return r;
978 }
979 }
980
981 dm_bitset_cursor_end(&cmd->dirty_cursor);
982
983 return 0;
984}
985
986static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
987 dm_cblock_t begin, dm_cblock_t end,
988 bool *result)
989{
990 if (separate_dirty_bits(cmd))
991 return blocks_are_clean_separate_dirty(cmd, begin, end, result);
992 else
993 return blocks_are_clean_combined_dirty(cmd, begin, end, result);
994}
995
996static bool cmd_write_lock(struct dm_cache_metadata *cmd)
997{
998 down_write(&cmd->root_lock);
999 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
1000 up_write(&cmd->root_lock);
1001 return false;
1002 }
1003 return true;
1004}
1005
1006#define WRITE_LOCK(cmd) \
1007 do { \
1008 if (!cmd_write_lock((cmd))) \
1009 return -EINVAL; \
1010 } while(0)
1011
1012#define WRITE_LOCK_VOID(cmd) \
1013 do { \
1014 if (!cmd_write_lock((cmd))) \
1015 return; \
1016 } while(0)
1017
1018#define WRITE_UNLOCK(cmd) \
1019 up_write(&(cmd)->root_lock)
1020
1021static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1022{
1023 down_read(&cmd->root_lock);
1024 if (cmd->fail_io) {
1025 up_read(&cmd->root_lock);
1026 return false;
1027 }
1028 return true;
1029}
1030
1031#define READ_LOCK(cmd) \
1032 do { \
1033 if (!cmd_read_lock((cmd))) \
1034 return -EINVAL; \
1035 } while(0)
1036
1037#define READ_LOCK_VOID(cmd) \
1038 do { \
1039 if (!cmd_read_lock((cmd))) \
1040 return; \
1041 } while(0)
1042
1043#define READ_UNLOCK(cmd) \
1044 up_read(&(cmd)->root_lock)
1045
1046int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1047{
1048 int r;
1049 bool clean;
1050 __le64 null_mapping = pack_value(0, 0);
1051
1052 WRITE_LOCK(cmd);
1053 __dm_bless_for_disk(&null_mapping);
1054
1055 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1056 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
1057 if (r) {
1058 __dm_unbless_for_disk(&null_mapping);
1059 goto out;
1060 }
1061
1062 if (!clean) {
1063 DMERR("unable to shrink cache due to dirty blocks");
1064 r = -EINVAL;
1065 __dm_unbless_for_disk(&null_mapping);
1066 goto out;
1067 }
1068 }
1069
1070 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1071 from_cblock(new_cache_size),
1072 &null_mapping, &cmd->root);
1073 if (r)
1074 goto out;
1075
1076 if (separate_dirty_bits(cmd)) {
1077 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1078 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1079 false, &cmd->dirty_root);
1080 if (r)
1081 goto out;
1082 }
1083
1084 cmd->cache_blocks = new_cache_size;
1085 cmd->changed = true;
1086
1087out:
1088 WRITE_UNLOCK(cmd);
1089
1090 return r;
1091}
1092
1093int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1094 sector_t discard_block_size,
1095 dm_dblock_t new_nr_entries)
1096{
1097 int r;
1098
1099 WRITE_LOCK(cmd);
1100 r = dm_bitset_resize(&cmd->discard_info,
1101 cmd->discard_root,
1102 from_dblock(cmd->discard_nr_blocks),
1103 from_dblock(new_nr_entries),
1104 false, &cmd->discard_root);
1105 if (!r) {
1106 cmd->discard_block_size = discard_block_size;
1107 cmd->discard_nr_blocks = new_nr_entries;
1108 }
1109
1110 cmd->changed = true;
1111 WRITE_UNLOCK(cmd);
1112
1113 return r;
1114}
1115
1116static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1117{
1118 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
1119 from_dblock(b), &cmd->discard_root);
1120}
1121
1122static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1123{
1124 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
1125 from_dblock(b), &cmd->discard_root);
1126}
1127
1128static int __discard(struct dm_cache_metadata *cmd,
1129 dm_dblock_t dblock, bool discard)
1130{
1131 int r;
1132
1133 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1134 if (r)
1135 return r;
1136
1137 cmd->changed = true;
1138 return 0;
1139}
1140
1141int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1142 dm_dblock_t dblock, bool discard)
1143{
1144 int r;
1145
1146 WRITE_LOCK(cmd);
1147 r = __discard(cmd, dblock, discard);
1148 WRITE_UNLOCK(cmd);
1149
1150 return r;
1151}
1152
1153static int __load_discards(struct dm_cache_metadata *cmd,
1154 load_discard_fn fn, void *context)
1155{
1156 int r = 0;
1157 uint32_t b;
1158 struct dm_bitset_cursor c;
1159
1160 if (from_dblock(cmd->discard_nr_blocks) == 0)
1161 /* nothing to do */
1162 return 0;
1163
1164 if (cmd->clean_when_opened) {
1165 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1166 if (r)
1167 return r;
1168
1169 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1170 from_dblock(cmd->discard_nr_blocks), &c);
1171 if (r)
1172 return r;
1173
1174 for (b = 0; ; b++) {
1175 r = fn(context, cmd->discard_block_size, to_dblock(b),
1176 dm_bitset_cursor_get_value(&c));
1177 if (r)
1178 break;
1179
1180 if (b >= (from_dblock(cmd->discard_nr_blocks) - 1))
1181 break;
1182
1183 r = dm_bitset_cursor_next(&c);
1184 if (r)
1185 break;
1186 }
1187
1188 dm_bitset_cursor_end(&c);
1189
1190 } else {
1191 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1192 r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1193 if (r)
1194 return r;
1195 }
1196 }
1197
1198 return r;
1199}
1200
1201int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1202 load_discard_fn fn, void *context)
1203{
1204 int r;
1205
1206 READ_LOCK(cmd);
1207 r = __load_discards(cmd, fn, context);
1208 READ_UNLOCK(cmd);
1209
1210 return r;
1211}
1212
1213int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1214{
1215 READ_LOCK(cmd);
1216 *result = cmd->cache_blocks;
1217 READ_UNLOCK(cmd);
1218
1219 return 0;
1220}
1221
1222static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1223{
1224 int r;
1225 __le64 value = pack_value(0, 0);
1226
1227 __dm_bless_for_disk(&value);
1228 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1229 &value, &cmd->root);
1230 if (r)
1231 return r;
1232
1233 cmd->changed = true;
1234 return 0;
1235}
1236
1237int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1238{
1239 int r;
1240
1241 WRITE_LOCK(cmd);
1242 r = __remove(cmd, cblock);
1243 WRITE_UNLOCK(cmd);
1244
1245 return r;
1246}
1247
1248static int __insert(struct dm_cache_metadata *cmd,
1249 dm_cblock_t cblock, dm_oblock_t oblock)
1250{
1251 int r;
1252 __le64 value = pack_value(oblock, M_VALID);
1253 __dm_bless_for_disk(&value);
1254
1255 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1256 &value, &cmd->root);
1257 if (r)
1258 return r;
1259
1260 cmd->changed = true;
1261 return 0;
1262}
1263
1264int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1265 dm_cblock_t cblock, dm_oblock_t oblock)
1266{
1267 int r;
1268
1269 WRITE_LOCK(cmd);
1270 r = __insert(cmd, cblock, oblock);
1271 WRITE_UNLOCK(cmd);
1272
1273 return r;
1274}
1275
1276struct thunk {
1277 load_mapping_fn fn;
1278 void *context;
1279
1280 struct dm_cache_metadata *cmd;
1281 bool respect_dirty_flags;
1282 bool hints_valid;
1283};
1284
1285static bool policy_unchanged(struct dm_cache_metadata *cmd,
1286 struct dm_cache_policy *policy)
1287{
1288 const char *policy_name = dm_cache_policy_get_name(policy);
1289 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1290 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1291
1292 /*
1293 * Ensure policy names match.
1294 */
1295 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1296 return false;
1297
1298 /*
1299 * Ensure policy major versions match.
1300 */
1301 if (cmd->policy_version[0] != policy_version[0])
1302 return false;
1303
1304 /*
1305 * Ensure policy hint sizes match.
1306 */
1307 if (cmd->policy_hint_size != policy_hint_size)
1308 return false;
1309
1310 return true;
1311}
1312
1313static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1314{
1315 return cmd->hint_root && cmd->policy_hint_size;
1316}
1317
1318static bool hints_array_available(struct dm_cache_metadata *cmd,
1319 struct dm_cache_policy *policy)
1320{
1321 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1322 hints_array_initialized(cmd);
1323}
1324
1325static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1326 uint64_t cb, bool hints_valid,
1327 struct dm_array_cursor *mapping_cursor,
1328 struct dm_array_cursor *hint_cursor,
1329 load_mapping_fn fn, void *context)
1330{
1331 int r = 0;
1332
1333 __le64 mapping;
1334 __le32 hint = 0;
1335
1336 __le64 *mapping_value_le;
1337 __le32 *hint_value_le;
1338
1339 dm_oblock_t oblock;
1340 unsigned flags;
1341 bool dirty = true;
1342
1343 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1344 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1345 unpack_value(mapping, &oblock, &flags);
1346
1347 if (flags & M_VALID) {
1348 if (hints_valid) {
1349 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1350 memcpy(&hint, hint_value_le, sizeof(hint));
1351 }
1352 if (cmd->clean_when_opened)
1353 dirty = flags & M_DIRTY;
1354
1355 r = fn(context, oblock, to_cblock(cb), dirty,
1356 le32_to_cpu(hint), hints_valid);
1357 if (r) {
1358 DMERR("policy couldn't load cache block %llu",
1359 (unsigned long long) from_cblock(to_cblock(cb)));
1360 }
1361 }
1362
1363 return r;
1364}
1365
1366static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1367 uint64_t cb, bool hints_valid,
1368 struct dm_array_cursor *mapping_cursor,
1369 struct dm_array_cursor *hint_cursor,
1370 struct dm_bitset_cursor *dirty_cursor,
1371 load_mapping_fn fn, void *context)
1372{
1373 int r = 0;
1374
1375 __le64 mapping;
1376 __le32 hint = 0;
1377
1378 __le64 *mapping_value_le;
1379 __le32 *hint_value_le;
1380
1381 dm_oblock_t oblock;
1382 unsigned flags;
1383 bool dirty = true;
1384
1385 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1386 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1387 unpack_value(mapping, &oblock, &flags);
1388
1389 if (flags & M_VALID) {
1390 if (hints_valid) {
1391 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1392 memcpy(&hint, hint_value_le, sizeof(hint));
1393 }
1394 if (cmd->clean_when_opened)
1395 dirty = dm_bitset_cursor_get_value(dirty_cursor);
1396
1397 r = fn(context, oblock, to_cblock(cb), dirty,
1398 le32_to_cpu(hint), hints_valid);
1399 if (r) {
1400 DMERR("policy couldn't load cache block %llu",
1401 (unsigned long long) from_cblock(to_cblock(cb)));
1402 }
1403 }
1404
1405 return r;
1406}
1407
1408static int __load_mappings(struct dm_cache_metadata *cmd,
1409 struct dm_cache_policy *policy,
1410 load_mapping_fn fn, void *context)
1411{
1412 int r;
1413 uint64_t cb;
1414
1415 bool hints_valid = hints_array_available(cmd, policy);
1416
1417 if (from_cblock(cmd->cache_blocks) == 0)
1418 /* Nothing to do */
1419 return 0;
1420
1421 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1422 if (r)
1423 return r;
1424
1425 if (hints_valid) {
1426 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1427 if (r) {
1428 dm_array_cursor_end(&cmd->mapping_cursor);
1429 return r;
1430 }
1431 }
1432
1433 if (separate_dirty_bits(cmd)) {
1434 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1435 from_cblock(cmd->cache_blocks),
1436 &cmd->dirty_cursor);
1437 if (r) {
1438 dm_array_cursor_end(&cmd->hint_cursor);
1439 dm_array_cursor_end(&cmd->mapping_cursor);
1440 return r;
1441 }
1442 }
1443
1444 for (cb = 0; ; cb++) {
1445 if (separate_dirty_bits(cmd))
1446 r = __load_mapping_v2(cmd, cb, hints_valid,
1447 &cmd->mapping_cursor,
1448 &cmd->hint_cursor,
1449 &cmd->dirty_cursor,
1450 fn, context);
1451 else
1452 r = __load_mapping_v1(cmd, cb, hints_valid,
1453 &cmd->mapping_cursor, &cmd->hint_cursor,
1454 fn, context);
1455 if (r)
1456 goto out;
1457
1458 /*
1459 * We need to break out before we move the cursors.
1460 */
1461 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1462 break;
1463
1464 r = dm_array_cursor_next(&cmd->mapping_cursor);
1465 if (r) {
1466 DMERR("dm_array_cursor_next for mapping failed");
1467 goto out;
1468 }
1469
1470 if (hints_valid) {
1471 r = dm_array_cursor_next(&cmd->hint_cursor);
1472 if (r) {
1473 dm_array_cursor_end(&cmd->hint_cursor);
1474 hints_valid = false;
1475 }
1476 }
1477
1478 if (separate_dirty_bits(cmd)) {
1479 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1480 if (r) {
1481 DMERR("dm_bitset_cursor_next for dirty failed");
1482 goto out;
1483 }
1484 }
1485 }
1486out:
1487 dm_array_cursor_end(&cmd->mapping_cursor);
1488 if (hints_valid)
1489 dm_array_cursor_end(&cmd->hint_cursor);
1490
1491 if (separate_dirty_bits(cmd))
1492 dm_bitset_cursor_end(&cmd->dirty_cursor);
1493
1494 return r;
1495}
1496
1497int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1498 struct dm_cache_policy *policy,
1499 load_mapping_fn fn, void *context)
1500{
1501 int r;
1502
1503 READ_LOCK(cmd);
1504 r = __load_mappings(cmd, policy, fn, context);
1505 READ_UNLOCK(cmd);
1506
1507 return r;
1508}
1509
1510static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1511{
1512 int r = 0;
1513 __le64 value;
1514 dm_oblock_t oblock;
1515 unsigned flags;
1516
1517 memcpy(&value, leaf, sizeof(value));
1518 unpack_value(value, &oblock, &flags);
1519
1520 return r;
1521}
1522
1523static int __dump_mappings(struct dm_cache_metadata *cmd)
1524{
1525 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1526}
1527
1528void dm_cache_dump(struct dm_cache_metadata *cmd)
1529{
1530 READ_LOCK_VOID(cmd);
1531 __dump_mappings(cmd);
1532 READ_UNLOCK(cmd);
1533}
1534
1535int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1536{
1537 int r;
1538
1539 READ_LOCK(cmd);
1540 r = cmd->changed;
1541 READ_UNLOCK(cmd);
1542
1543 return r;
1544}
1545
1546static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1547{
1548 int r;
1549 unsigned flags;
1550 dm_oblock_t oblock;
1551 __le64 value;
1552
1553 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1554 if (r)
1555 return r;
1556
1557 unpack_value(value, &oblock, &flags);
1558
1559 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1560 /* nothing to be done */
1561 return 0;
1562
1563 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1564 __dm_bless_for_disk(&value);
1565
1566 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1567 &value, &cmd->root);
1568 if (r)
1569 return r;
1570
1571 cmd->changed = true;
1572 return 0;
1573
1574}
1575
1576static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1577{
1578 int r;
1579 unsigned i;
1580 for (i = 0; i < nr_bits; i++) {
1581 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1582 if (r)
1583 return r;
1584 }
1585
1586 return 0;
1587}
1588
1589static int is_dirty_callback(uint32_t index, bool *value, void *context)
1590{
1591 unsigned long *bits = context;
1592 *value = test_bit(index, bits);
1593 return 0;
1594}
1595
1596static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1597{
1598 int r = 0;
1599
1600 /* nr_bits is really just a sanity check */
1601 if (nr_bits != from_cblock(cmd->cache_blocks)) {
1602 DMERR("dirty bitset is wrong size");
1603 return -EINVAL;
1604 }
1605
1606 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1607 if (r)
1608 return r;
1609
1610 cmd->changed = true;
1611 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1612}
1613
1614int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1615 unsigned nr_bits,
1616 unsigned long *bits)
1617{
1618 int r;
1619
1620 WRITE_LOCK(cmd);
1621 if (separate_dirty_bits(cmd))
1622 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1623 else
1624 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1625 WRITE_UNLOCK(cmd);
1626
1627 return r;
1628}
1629
1630void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1631 struct dm_cache_statistics *stats)
1632{
1633 READ_LOCK_VOID(cmd);
1634 *stats = cmd->stats;
1635 READ_UNLOCK(cmd);
1636}
1637
1638void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1639 struct dm_cache_statistics *stats)
1640{
1641 WRITE_LOCK_VOID(cmd);
1642 cmd->stats = *stats;
1643 WRITE_UNLOCK(cmd);
1644}
1645
1646int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1647{
1648 int r = -EINVAL;
1649 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1650 clear_clean_shutdown);
1651
1652 WRITE_LOCK(cmd);
1653 if (cmd->fail_io)
1654 goto out;
1655
1656 r = __commit_transaction(cmd, mutator);
1657 if (r)
1658 goto out;
1659
1660 r = __begin_transaction(cmd);
1661out:
1662 WRITE_UNLOCK(cmd);
1663 return r;
1664}
1665
1666int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1667 dm_block_t *result)
1668{
1669 int r = -EINVAL;
1670
1671 READ_LOCK(cmd);
1672 if (!cmd->fail_io)
1673 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1674 READ_UNLOCK(cmd);
1675
1676 return r;
1677}
1678
1679int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1680 dm_block_t *result)
1681{
1682 int r = -EINVAL;
1683
1684 READ_LOCK(cmd);
1685 if (!cmd->fail_io)
1686 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1687 READ_UNLOCK(cmd);
1688
1689 return r;
1690}
1691
1692/*----------------------------------------------------------------*/
1693
1694static int get_hint(uint32_t index, void *value_le, void *context)
1695{
1696 uint32_t value;
1697 struct dm_cache_policy *policy = context;
1698
1699 value = policy_get_hint(policy, to_cblock(index));
1700 *((__le32 *) value_le) = cpu_to_le32(value);
1701
1702 return 0;
1703}
1704
1705/*
1706 * It's quicker to always delete the hint array, and recreate with
1707 * dm_array_new().
1708 */
1709static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1710{
1711 int r;
1712 size_t hint_size;
1713 const char *policy_name = dm_cache_policy_get_name(policy);
1714 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1715
1716 if (!policy_name[0] ||
1717 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1718 return -EINVAL;
1719
1720 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1721 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1722
1723 hint_size = dm_cache_policy_get_hint_size(policy);
1724 if (!hint_size)
1725 return 0; /* short-circuit hints initialization */
1726 cmd->policy_hint_size = hint_size;
1727
1728 if (cmd->hint_root) {
1729 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1730 if (r)
1731 return r;
1732 }
1733
1734 return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1735 from_cblock(cmd->cache_blocks),
1736 get_hint, policy);
1737}
1738
1739int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1740{
1741 int r;
1742
1743 WRITE_LOCK(cmd);
1744 r = write_hints(cmd, policy);
1745 WRITE_UNLOCK(cmd);
1746
1747 return r;
1748}
1749
1750int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1751{
1752 int r;
1753
1754 READ_LOCK(cmd);
1755 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1756 READ_UNLOCK(cmd);
1757
1758 return r;
1759}
1760
1761void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1762{
1763 WRITE_LOCK_VOID(cmd);
1764 dm_bm_set_read_only(cmd->bm);
1765 WRITE_UNLOCK(cmd);
1766}
1767
1768void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1769{
1770 WRITE_LOCK_VOID(cmd);
1771 dm_bm_set_read_write(cmd->bm);
1772 WRITE_UNLOCK(cmd);
1773}
1774
1775int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1776{
1777 int r;
1778 struct dm_block *sblock;
1779 struct cache_disk_superblock *disk_super;
1780
1781 WRITE_LOCK(cmd);
1782 set_bit(NEEDS_CHECK, &cmd->flags);
1783
1784 r = superblock_lock(cmd, &sblock);
1785 if (r) {
1786 DMERR("couldn't read superblock");
1787 goto out;
1788 }
1789
1790 disk_super = dm_block_data(sblock);
1791 disk_super->flags = cpu_to_le32(cmd->flags);
1792
1793 dm_bm_unlock(sblock);
1794
1795out:
1796 WRITE_UNLOCK(cmd);
1797 return r;
1798}
1799
1800int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1801{
1802 READ_LOCK(cmd);
1803 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1804 READ_UNLOCK(cmd);
1805
1806 return 0;
1807}
1808
1809int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1810{
1811 int r;
1812
1813 WRITE_LOCK(cmd);
1814 __destroy_persistent_data_objects(cmd);
1815 r = __create_persistent_data_objects(cmd, false);
1816 if (r)
1817 cmd->fail_io = true;
1818 WRITE_UNLOCK(cmd);
1819
1820 return r;
1821}
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}