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Merge tag 'dt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
[linux-2.6-block.git] / drivers / md / dm-cache-metadata.c
CommitLineData
c6b4fcba
JT		 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
53d49819
JT		 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
c6b4fcba
JT		 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};
43
44/*
45 * Each mapping from cache block -> origin block carries a set of flags.
46 */
47enum mapping_bits {
48 /*
49 * A valid mapping. Because we're using an array we clear this
50 * flag for an non existant mapping.
51 */
52 M_VALID = 1,
53
54 /*
55 * The data on the cache is different from that on the origin.
56 */
57 M_DIRTY = 2
58};
59
60struct cache_disk_superblock {
61 __le32 csum;
62 __le32 flags;
63 __le64 blocknr;
64
65 __u8 uuid[16];
66 __le64 magic;
67 __le32 version;
68
69 __u8 policy_name[CACHE_POLICY_NAME_SIZE];
70 __le32 policy_hint_size;
71
72 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
73 __le64 mapping_root;
74 __le64 hint_root;
75
76 __le64 discard_root;
77 __le64 discard_block_size;
78 __le64 discard_nr_blocks;
79
80 __le32 data_block_size;
81 __le32 metadata_block_size;
82 __le32 cache_blocks;
83
84 __le32 compat_flags;
85 __le32 compat_ro_flags;
86 __le32 incompat_flags;
87
88 __le32 read_hits;
89 __le32 read_misses;
90 __le32 write_hits;
91 __le32 write_misses;
4e7f506f
MS		 92
93 __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
c6b4fcba
JT		 94} __packed;
95
96struct dm_cache_metadata {
97 struct block_device *bdev;
98 struct dm_block_manager *bm;
99 struct dm_space_map *metadata_sm;
100 struct dm_transaction_manager *tm;
101
102 struct dm_array_info info;
103 struct dm_array_info hint_info;
104 struct dm_disk_bitset discard_info;
105
106 struct rw_semaphore root_lock;
107 dm_block_t root;
108 dm_block_t hint_root;
109 dm_block_t discard_root;
110
111 sector_t discard_block_size;
112 dm_dblock_t discard_nr_blocks;
113
114 sector_t data_block_size;
115 dm_cblock_t cache_blocks;
116 bool changed:1;
117 bool clean_when_opened:1;
118
119 char policy_name[CACHE_POLICY_NAME_SIZE];
4e7f506f 120 unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
c6b4fcba
JT		 121 size_t policy_hint_size;
122 struct dm_cache_statistics stats;
123};
124
125/*-------------------------------------------------------------------
126 * superblock validator
127 *-----------------------------------------------------------------*/
128
129#define SUPERBLOCK_CSUM_XOR 9031977
130
131static void sb_prepare_for_write(struct dm_block_validator *v,
132 struct dm_block *b,
133 size_t sb_block_size)
134{
135 struct cache_disk_superblock *disk_super = dm_block_data(b);
136
137 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
138 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
139 sb_block_size - sizeof(__le32),
140 SUPERBLOCK_CSUM_XOR));
141}
142
53d49819
JT		 143static int check_metadata_version(struct cache_disk_superblock *disk_super)
144{
145 uint32_t metadata_version = le32_to_cpu(disk_super->version);
146 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
147 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
148 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
149 return -EINVAL;
150 }
151
152 return 0;
153}
154
c6b4fcba
JT		 155static int sb_check(struct dm_block_validator *v,
156 struct dm_block *b,
157 size_t sb_block_size)
158{
159 struct cache_disk_superblock *disk_super = dm_block_data(b);
160 __le32 csum_le;
161
162 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
163 DMERR("sb_check failed: blocknr %llu: wanted %llu",
164 le64_to_cpu(disk_super->blocknr),
165 (unsigned long long)dm_block_location(b));
166 return -ENOTBLK;
167 }
168
169 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
170 DMERR("sb_check failed: magic %llu: wanted %llu",
171 le64_to_cpu(disk_super->magic),
172 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
173 return -EILSEQ;
174 }
175
176 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
177 sb_block_size - sizeof(__le32),
178 SUPERBLOCK_CSUM_XOR));
179 if (csum_le != disk_super->csum) {
180 DMERR("sb_check failed: csum %u: wanted %u",
181 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
182 return -EILSEQ;
183 }
184
53d49819 185 return check_metadata_version(disk_super);
c6b4fcba
JT		 186}
187
188static struct dm_block_validator sb_validator = {
189 .name = "superblock",
190 .prepare_for_write = sb_prepare_for_write,
191 .check = sb_check
192};
193
194/*----------------------------------------------------------------*/
195
196static int superblock_read_lock(struct dm_cache_metadata *cmd,
197 struct dm_block **sblock)
198{
199 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
200 &sb_validator, sblock);
201}
202
203static int superblock_lock_zero(struct dm_cache_metadata *cmd,
204 struct dm_block **sblock)
205{
206 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
207 &sb_validator, sblock);
208}
209
210static int superblock_lock(struct dm_cache_metadata *cmd,
211 struct dm_block **sblock)
212{
213 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
214 &sb_validator, sblock);
215}
216
217/*----------------------------------------------------------------*/
218
dd8b0c20 219static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
c6b4fcba
JT		 220{
221 int r;
222 unsigned i;
223 struct dm_block *b;
224 __le64 *data_le, zero = cpu_to_le64(0);
225 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
226
227 /*
228 * We can't use a validator here - it may be all zeroes.
229 */
230 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
231 if (r)
232 return r;
233
234 data_le = dm_block_data(b);
dd8b0c20 235 *result = true;
c6b4fcba
JT		 236 for (i = 0; i < sb_block_size; i++) {
237 if (data_le[i] != zero) {
dd8b0c20 238 *result = false;
c6b4fcba
JT		 239 break;
240 }
241 }
242
243 return dm_bm_unlock(b);
244}
245
246static void __setup_mapping_info(struct dm_cache_metadata *cmd)
247{
248 struct dm_btree_value_type vt;
249
250 vt.context = NULL;
251 vt.size = sizeof(__le64);
252 vt.inc = NULL;
253 vt.dec = NULL;
254 vt.equal = NULL;
255 dm_array_info_init(&cmd->info, cmd->tm, &vt);
256
257 if (cmd->policy_hint_size) {
258 vt.size = sizeof(__le32);
259 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
260 }
261}
262
263static int __write_initial_superblock(struct dm_cache_metadata *cmd)
264{
265 int r;
266 struct dm_block *sblock;
267 size_t metadata_len;
268 struct cache_disk_superblock *disk_super;
269 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
270
271 /* FIXME: see if we can lose the max sectors limit */
272 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
273 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
274
275 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
276 if (r < 0)
277 return r;
278
279 r = dm_tm_pre_commit(cmd->tm);
280 if (r < 0)
281 return r;
282
283 r = superblock_lock_zero(cmd, &sblock);
284 if (r)
285 return r;
286
287 disk_super = dm_block_data(sblock);
288 disk_super->flags = 0;
289 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
290 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
53d49819 291 disk_super->version = cpu_to_le32(MAX_CACHE_VERSION);
4e7f506f
MS		 292 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
293 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
c6b4fcba
JT		 294 disk_super->policy_hint_size = 0;
295
296 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
297 metadata_len);
298 if (r < 0)
299 goto bad_locked;
300
301 disk_super->mapping_root = cpu_to_le64(cmd->root);
302 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
303 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
304 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
305 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
306 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
307 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
308 disk_super->cache_blocks = cpu_to_le32(0);
c6b4fcba
JT		 309
310 disk_super->read_hits = cpu_to_le32(0);
311 disk_super->read_misses = cpu_to_le32(0);
312 disk_super->write_hits = cpu_to_le32(0);
313 disk_super->write_misses = cpu_to_le32(0);
314
315 return dm_tm_commit(cmd->tm, sblock);
316
317bad_locked:
318 dm_bm_unlock(sblock);
319 return r;
320}
321
322static int __format_metadata(struct dm_cache_metadata *cmd)
323{
324 int r;
325
326 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
327 &cmd->tm, &cmd->metadata_sm);
328 if (r < 0) {
329 DMERR("tm_create_with_sm failed");
330 return r;
331 }
332
333 __setup_mapping_info(cmd);
334
335 r = dm_array_empty(&cmd->info, &cmd->root);
336 if (r < 0)
337 goto bad;
338
339 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
340
341 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
342 if (r < 0)
343 goto bad;
344
345 cmd->discard_block_size = 0;
346 cmd->discard_nr_blocks = 0;
347
348 r = __write_initial_superblock(cmd);
349 if (r)
350 goto bad;
351
352 cmd->clean_when_opened = true;
353 return 0;
354
355bad:
356 dm_tm_destroy(cmd->tm);
357 dm_sm_destroy(cmd->metadata_sm);
358
359 return r;
360}
361
362static int __check_incompat_features(struct cache_disk_superblock *disk_super,
363 struct dm_cache_metadata *cmd)
364{
365 uint32_t features;
366
367 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
368 if (features) {
369 DMERR("could not access metadata due to unsupported optional features (%lx).",
370 (unsigned long)features);
371 return -EINVAL;
372 }
373
374 /*
375 * Check for read-only metadata to skip the following RDWR checks.
376 */
377 if (get_disk_ro(cmd->bdev->bd_disk))
378 return 0;
379
380 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
381 if (features) {
382 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
383 (unsigned long)features);
384 return -EINVAL;
385 }
386
387 return 0;
388}
389
390static int __open_metadata(struct dm_cache_metadata *cmd)
391{
392 int r;
393 struct dm_block *sblock;
394 struct cache_disk_superblock *disk_super;
395 unsigned long sb_flags;
396
397 r = superblock_read_lock(cmd, &sblock);
398 if (r < 0) {
399 DMERR("couldn't read lock superblock");
400 return r;
401 }
402
403 disk_super = dm_block_data(sblock);
404
405 r = __check_incompat_features(disk_super, cmd);
406 if (r < 0)
407 goto bad;
408
409 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
410 disk_super->metadata_space_map_root,
411 sizeof(disk_super->metadata_space_map_root),
412 &cmd->tm, &cmd->metadata_sm);
413 if (r < 0) {
414 DMERR("tm_open_with_sm failed");
415 goto bad;
416 }
417
418 __setup_mapping_info(cmd);
419 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
420 sb_flags = le32_to_cpu(disk_super->flags);
421 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
422 return dm_bm_unlock(sblock);
423
424bad:
425 dm_bm_unlock(sblock);
426 return r;
427}
428
429static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
430 bool format_device)
431{
dd8b0c20
JT		 432 int r;
433 bool unformatted = false;
c6b4fcba
JT		 434
435 r = __superblock_all_zeroes(cmd->bm, &unformatted);
436 if (r)
437 return r;
438
439 if (unformatted)
440 return format_device ? __format_metadata(cmd) : -EPERM;
441
442 return __open_metadata(cmd);
443}
444
445static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
446 bool may_format_device)
447{
448 int r;
449 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE,
450 CACHE_METADATA_CACHE_SIZE,
451 CACHE_MAX_CONCURRENT_LOCKS);
452 if (IS_ERR(cmd->bm)) {
453 DMERR("could not create block manager");
454 return PTR_ERR(cmd->bm);
455 }
456
457 r = __open_or_format_metadata(cmd, may_format_device);
458 if (r)
459 dm_block_manager_destroy(cmd->bm);
460
461 return r;
462}
463
464static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
465{
466 dm_sm_destroy(cmd->metadata_sm);
467 dm_tm_destroy(cmd->tm);
468 dm_block_manager_destroy(cmd->bm);
469}
470
471typedef unsigned long (*flags_mutator)(unsigned long);
472
473static void update_flags(struct cache_disk_superblock *disk_super,
474 flags_mutator mutator)
475{
476 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
477 disk_super->flags = cpu_to_le32(sb_flags);
478}
479
480static unsigned long set_clean_shutdown(unsigned long flags)
481{
482 set_bit(CLEAN_SHUTDOWN, &flags);
483 return flags;
484}
485
486static unsigned long clear_clean_shutdown(unsigned long flags)
487{
488 clear_bit(CLEAN_SHUTDOWN, &flags);
489 return flags;
490}
491
492static void read_superblock_fields(struct dm_cache_metadata *cmd,
493 struct cache_disk_superblock *disk_super)
494{
495 cmd->root = le64_to_cpu(disk_super->mapping_root);
496 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
497 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
498 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
499 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
500 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
501 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
502 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
4e7f506f
MS		 503 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
504 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
505 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
c6b4fcba
JT		 506 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
507
508 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
509 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
510 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
511 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
512
513 cmd->changed = false;
514}
515
516/*
517 * The mutator updates the superblock flags.
518 */
519static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
520 flags_mutator mutator)
521{
522 int r;
523 struct cache_disk_superblock *disk_super;
524 struct dm_block *sblock;
525
526 r = superblock_lock(cmd, &sblock);
527 if (r)
528 return r;
529
530 disk_super = dm_block_data(sblock);
531 update_flags(disk_super, mutator);
532 read_superblock_fields(cmd, disk_super);
533
534 return dm_bm_flush_and_unlock(cmd->bm, sblock);
535}
536
537static int __begin_transaction(struct dm_cache_metadata *cmd)
538{
539 int r;
540 struct cache_disk_superblock *disk_super;
541 struct dm_block *sblock;
542
543 /*
544 * We re-read the superblock every time. Shouldn't need to do this
545 * really.
546 */
547 r = superblock_read_lock(cmd, &sblock);
548 if (r)
549 return r;
550
551 disk_super = dm_block_data(sblock);
552 read_superblock_fields(cmd, disk_super);
553 dm_bm_unlock(sblock);
554
555 return 0;
556}
557
558static int __commit_transaction(struct dm_cache_metadata *cmd,
559 flags_mutator mutator)
560{
561 int r;
562 size_t metadata_len;
563 struct cache_disk_superblock *disk_super;
564 struct dm_block *sblock;
565
566 /*
567 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
568 */
569 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
570
571 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
572 &cmd->discard_root);
573 if (r)
574 return r;
575
576 r = dm_tm_pre_commit(cmd->tm);
577 if (r < 0)
578 return r;
579
580 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
581 if (r < 0)
582 return r;
583
584 r = superblock_lock(cmd, &sblock);
585 if (r)
586 return r;
587
588 disk_super = dm_block_data(sblock);
589
590 if (mutator)
591 update_flags(disk_super, mutator);
592
593 disk_super->mapping_root = cpu_to_le64(cmd->root);
594 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
595 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
596 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
597 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
598 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
599 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
4e7f506f
MS		 600 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
601 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
602 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
c6b4fcba
JT		 603
604 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
605 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
606 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
607 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
608
609 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
610 metadata_len);
611 if (r < 0) {
612 dm_bm_unlock(sblock);
613 return r;
614 }
615
616 return dm_tm_commit(cmd->tm, sblock);
617}
618
619/*----------------------------------------------------------------*/
620
621/*
622 * The mappings are held in a dm-array that has 64-bit values stored in
623 * little-endian format. The index is the cblock, the high 48bits of the
624 * value are the oblock and the low 16 bit the flags.
625 */
626#define FLAGS_MASK ((1 << 16) - 1)
627
628static __le64 pack_value(dm_oblock_t block, unsigned flags)
629{
630 uint64_t value = from_oblock(block);
631 value <<= 16;
632 value = value | (flags & FLAGS_MASK);
633 return cpu_to_le64(value);
634}
635
636static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
637{
638 uint64_t value = le64_to_cpu(value_le);
639 uint64_t b = value >> 16;
640 *block = to_oblock(b);
641 *flags = value & FLAGS_MASK;
642}
643
644/*----------------------------------------------------------------*/
645
646struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
647 sector_t data_block_size,
648 bool may_format_device,
649 size_t policy_hint_size)
650{
651 int r;
652 struct dm_cache_metadata *cmd;
653
654 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
655 if (!cmd) {
656 DMERR("could not allocate metadata struct");
657 return NULL;
658 }
659
660 init_rwsem(&cmd->root_lock);
661 cmd->bdev = bdev;
662 cmd->data_block_size = data_block_size;
663 cmd->cache_blocks = 0;
664 cmd->policy_hint_size = policy_hint_size;
665 cmd->changed = true;
666
667 r = __create_persistent_data_objects(cmd, may_format_device);
668 if (r) {
669 kfree(cmd);
670 return ERR_PTR(r);
671 }
672
673 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
674 if (r < 0) {
675 dm_cache_metadata_close(cmd);
676 return ERR_PTR(r);
677 }
678
679 return cmd;
680}
681
682void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
683{
684 __destroy_persistent_data_objects(cmd);
685 kfree(cmd);
686}
687
f494a9c6
JT		 688/*
689 * Checks that the given cache block is either unmapped or clean.
690 */
691static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
692 bool *result)
693{
694 int r;
695 __le64 value;
696 dm_oblock_t ob;
697 unsigned flags;
698
699 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
700 if (r) {
701 DMERR("block_unmapped_or_clean failed");
702 return r;
703 }
704
705 unpack_value(value, &ob, &flags);
706 *result = !((flags & M_VALID) && (flags & M_DIRTY));
707
708 return 0;
709}
710
711static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
712 dm_cblock_t begin, dm_cblock_t end,
713 bool *result)
714{
715 int r;
716 *result = true;
717
718 while (begin != end) {
719 r = block_unmapped_or_clean(cmd, begin, result);
720 if (r)
721 return r;
722
723 if (!*result) {
724 DMERR("cache block %llu is dirty",
725 (unsigned long long) from_cblock(begin));
726 return 0;
727 }
728
729 begin = to_cblock(from_cblock(begin) + 1);
730 }
731
732 return 0;
733}
734
c6b4fcba
JT		 735int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
736{
737 int r;
f494a9c6 738 bool clean;
c6b4fcba
JT		 739 __le64 null_mapping = pack_value(0, 0);
740
741 down_write(&cmd->root_lock);
742 __dm_bless_for_disk(&null_mapping);
f494a9c6
JT		 743
744 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
745 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
746 if (r) {
747 __dm_unbless_for_disk(&null_mapping);
748 goto out;
749 }
750
751 if (!clean) {
752 DMERR("unable to shrink cache due to dirty blocks");
753 r = -EINVAL;
754 __dm_unbless_for_disk(&null_mapping);
755 goto out;
756 }
757 }
758
c6b4fcba
JT		 759 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
760 from_cblock(new_cache_size),
761 &null_mapping, &cmd->root);
762 if (!r)
763 cmd->cache_blocks = new_cache_size;
764 cmd->changed = true;
f494a9c6
JT		 765
766out:
c6b4fcba
JT		 767 up_write(&cmd->root_lock);
768
769 return r;
770}
771
772int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
773 sector_t discard_block_size,
774 dm_dblock_t new_nr_entries)
775{
776 int r;
777
778 down_write(&cmd->root_lock);
779 r = dm_bitset_resize(&cmd->discard_info,
780 cmd->discard_root,
781 from_dblock(cmd->discard_nr_blocks),
782 from_dblock(new_nr_entries),
783 false, &cmd->discard_root);
784 if (!r) {
785 cmd->discard_block_size = discard_block_size;
786 cmd->discard_nr_blocks = new_nr_entries;
787 }
788
789 cmd->changed = true;
790 up_write(&cmd->root_lock);
791
792 return r;
793}
794
795static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
796{
797 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
798 from_dblock(b), &cmd->discard_root);
799}
800
801static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
802{
803 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
804 from_dblock(b), &cmd->discard_root);
805}
806
807static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
808 bool *is_discarded)
809{
810 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
811 from_dblock(b), &cmd->discard_root,
812 is_discarded);
813}
814
815static int __discard(struct dm_cache_metadata *cmd,
816 dm_dblock_t dblock, bool discard)
817{
818 int r;
819
820 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
821 if (r)
822 return r;
823
824 cmd->changed = true;
825 return 0;
826}
827
828int dm_cache_set_discard(struct dm_cache_metadata *cmd,
829 dm_dblock_t dblock, bool discard)
830{
831 int r;
832
833 down_write(&cmd->root_lock);
834 r = __discard(cmd, dblock, discard);
835 up_write(&cmd->root_lock);
836
837 return r;
838}
839
840static int __load_discards(struct dm_cache_metadata *cmd,
841 load_discard_fn fn, void *context)
842{
843 int r = 0;
844 dm_block_t b;
845 bool discard;
846
847 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
848 dm_dblock_t dblock = to_dblock(b);
849
850 if (cmd->clean_when_opened) {
851 r = __is_discarded(cmd, dblock, &discard);
852 if (r)
853 return r;
854 } else
855 discard = false;
856
857 r = fn(context, cmd->discard_block_size, dblock, discard);
858 if (r)
859 break;
860 }
861
862 return r;
863}
864
865int dm_cache_load_discards(struct dm_cache_metadata *cmd,
866 load_discard_fn fn, void *context)
867{
868 int r;
869
870 down_read(&cmd->root_lock);
871 r = __load_discards(cmd, fn, context);
872 up_read(&cmd->root_lock);
873
874 return r;
875}
876
877dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd)
878{
879 dm_cblock_t r;
880
881 down_read(&cmd->root_lock);
882 r = cmd->cache_blocks;
883 up_read(&cmd->root_lock);
884
885 return r;
886}
887
888static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
889{
890 int r;
891 __le64 value = pack_value(0, 0);
892
893 __dm_bless_for_disk(&value);
894 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
895 &value, &cmd->root);
896 if (r)
897 return r;
898
899 cmd->changed = true;
900 return 0;
901}
902
903int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
904{
905 int r;
906
907 down_write(&cmd->root_lock);
908 r = __remove(cmd, cblock);
909 up_write(&cmd->root_lock);
910
911 return r;
912}
913
914static int __insert(struct dm_cache_metadata *cmd,
915 dm_cblock_t cblock, dm_oblock_t oblock)
916{
917 int r;
918 __le64 value = pack_value(oblock, M_VALID);
919 __dm_bless_for_disk(&value);
920
921 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
922 &value, &cmd->root);
923 if (r)
924 return r;
925
926 cmd->changed = true;
927 return 0;
928}
929
930int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
931 dm_cblock_t cblock, dm_oblock_t oblock)
932{
933 int r;
934
935 down_write(&cmd->root_lock);
936 r = __insert(cmd, cblock, oblock);
937 up_write(&cmd->root_lock);
938
939 return r;
940}
941
942struct thunk {
943 load_mapping_fn fn;
944 void *context;
945
946 struct dm_cache_metadata *cmd;
947 bool respect_dirty_flags;
948 bool hints_valid;
949};
950
ea2dd8c1
MS		 951static bool policy_unchanged(struct dm_cache_metadata *cmd,
952 struct dm_cache_policy *policy)
953{
954 const char *policy_name = dm_cache_policy_get_name(policy);
955 const unsigned *policy_version = dm_cache_policy_get_version(policy);
956 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
957
958 /*
959 * Ensure policy names match.
960 */
961 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
962 return false;
963
964 /*
965 * Ensure policy major versions match.
966 */
967 if (cmd->policy_version[0] != policy_version[0])
968 return false;
969
970 /*
971 * Ensure policy hint sizes match.
972 */
973 if (cmd->policy_hint_size != policy_hint_size)
974 return false;
975
976 return true;
977}
978
c6b4fcba
JT		 979static bool hints_array_initialized(struct dm_cache_metadata *cmd)
980{
981 return cmd->hint_root && cmd->policy_hint_size;
982}
983
984static bool hints_array_available(struct dm_cache_metadata *cmd,
ea2dd8c1 985 struct dm_cache_policy *policy)
c6b4fcba 986{
ea2dd8c1 987 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
c6b4fcba
JT		 988 hints_array_initialized(cmd);
989}
990
991static int __load_mapping(void *context, uint64_t cblock, void *leaf)
992{
993 int r = 0;
994 bool dirty;
995 __le64 value;
996 __le32 hint_value = 0;
997 dm_oblock_t oblock;
998 unsigned flags;
999 struct thunk *thunk = context;
1000 struct dm_cache_metadata *cmd = thunk->cmd;
1001
1002 memcpy(&value, leaf, sizeof(value));
1003 unpack_value(value, &oblock, &flags);
1004
1005 if (flags & M_VALID) {
1006 if (thunk->hints_valid) {
1007 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,
1008 cblock, &hint_value);
1009 if (r && r != -ENODATA)
1010 return r;
1011 }
1012
1013 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;
1014 r = thunk->fn(thunk->context, oblock, to_cblock(cblock),
1015 dirty, le32_to_cpu(hint_value), thunk->hints_valid);
1016 }
1017
1018 return r;
1019}
1020
ea2dd8c1
MS		 1021static int __load_mappings(struct dm_cache_metadata *cmd,
1022 struct dm_cache_policy *policy,
c6b4fcba
JT		 1023 load_mapping_fn fn, void *context)
1024{
1025 struct thunk thunk;
1026
1027 thunk.fn = fn;
1028 thunk.context = context;
1029
1030 thunk.cmd = cmd;
1031 thunk.respect_dirty_flags = cmd->clean_when_opened;
ea2dd8c1 1032 thunk.hints_valid = hints_array_available(cmd, policy);
c6b4fcba
JT		 1033
1034 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);
1035}
1036
ea2dd8c1
MS		 1037int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1038 struct dm_cache_policy *policy,
c6b4fcba
JT		 1039 load_mapping_fn fn, void *context)
1040{
1041 int r;
1042
1043 down_read(&cmd->root_lock);
ea2dd8c1 1044 r = __load_mappings(cmd, policy, fn, context);
c6b4fcba
JT		 1045 up_read(&cmd->root_lock);
1046
1047 return r;
1048}
1049
1050static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1051{
1052 int r = 0;
1053 __le64 value;
1054 dm_oblock_t oblock;
1055 unsigned flags;
1056
1057 memcpy(&value, leaf, sizeof(value));
1058 unpack_value(value, &oblock, &flags);
1059
1060 return r;
1061}
1062
1063static int __dump_mappings(struct dm_cache_metadata *cmd)
1064{
1065 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1066}
1067
1068void dm_cache_dump(struct dm_cache_metadata *cmd)
1069{
1070 down_read(&cmd->root_lock);
1071 __dump_mappings(cmd);
1072 up_read(&cmd->root_lock);
1073}
1074
1075int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1076{
1077 int r;
1078
1079 down_read(&cmd->root_lock);
1080 r = cmd->changed;
1081 up_read(&cmd->root_lock);
1082
1083 return r;
1084}
1085
1086static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1087{
1088 int r;
1089 unsigned flags;
1090 dm_oblock_t oblock;
1091 __le64 value;
1092
1093 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1094 if (r)
1095 return r;
1096
1097 unpack_value(value, &oblock, &flags);
1098
1099 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1100 /* nothing to be done */
1101 return 0;
1102
79ed9caf 1103 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
c6b4fcba
JT		 1104 __dm_bless_for_disk(&value);
1105
1106 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1107 &value, &cmd->root);
1108 if (r)
1109 return r;
1110
1111 cmd->changed = true;
1112 return 0;
1113
1114}
1115
1116int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
1117 dm_cblock_t cblock, bool dirty)
1118{
1119 int r;
1120
1121 down_write(&cmd->root_lock);
1122 r = __dirty(cmd, cblock, dirty);
1123 up_write(&cmd->root_lock);
1124
1125 return r;
1126}
1127
1128void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1129 struct dm_cache_statistics *stats)
1130{
1131 down_read(&cmd->root_lock);
8c5008fa 1132 *stats = cmd->stats;
c6b4fcba
JT		 1133 up_read(&cmd->root_lock);
1134}
1135
1136void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1137 struct dm_cache_statistics *stats)
1138{
1139 down_write(&cmd->root_lock);
8c5008fa 1140 cmd->stats = *stats;
c6b4fcba
JT		 1141 up_write(&cmd->root_lock);
1142}
1143
1144int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1145{
1146 int r;
1147 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1148 clear_clean_shutdown);
1149
1150 down_write(&cmd->root_lock);
1151 r = __commit_transaction(cmd, mutator);
1152 if (r)
1153 goto out;
1154
1155 r = __begin_transaction(cmd);
1156
1157out:
1158 up_write(&cmd->root_lock);
1159 return r;
1160}
1161
1162int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1163 dm_block_t *result)
1164{
1165 int r = -EINVAL;
1166
1167 down_read(&cmd->root_lock);
1168 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1169 up_read(&cmd->root_lock);
1170
1171 return r;
1172}
1173
1174int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1175 dm_block_t *result)
1176{
1177 int r = -EINVAL;
1178
1179 down_read(&cmd->root_lock);
1180 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1181 up_read(&cmd->root_lock);
1182
1183 return r;
1184}
1185
1186/*----------------------------------------------------------------*/
1187
1188static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1189{
1190 int r;
1191 __le32 value;
1192 size_t hint_size;
1193 const char *policy_name = dm_cache_policy_get_name(policy);
4e7f506f 1194 const unsigned *policy_version = dm_cache_policy_get_version(policy);
c6b4fcba
JT		 1195
1196 if (!policy_name[0] ||
1197 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1198 return -EINVAL;
1199
ea2dd8c1 1200 if (!policy_unchanged(cmd, policy)) {
c6b4fcba 1201 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
4e7f506f 1202 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
c6b4fcba
JT		 1203
1204 hint_size = dm_cache_policy_get_hint_size(policy);
1205 if (!hint_size)
1206 return 0; /* short-circuit hints initialization */
1207 cmd->policy_hint_size = hint_size;
1208
1209 if (cmd->hint_root) {
1210 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1211 if (r)
1212 return r;
1213 }
1214
1215 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root);
1216 if (r)
1217 return r;
1218
1219 value = cpu_to_le32(0);
1220 __dm_bless_for_disk(&value);
1221 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0,
1222 from_cblock(cmd->cache_blocks),
1223 &value, &cmd->hint_root);
1224 if (r)
1225 return r;
1226 }
1227
1228 return 0;
1229}
1230
1231int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1232{
1233 int r;
1234
1235 down_write(&cmd->root_lock);
1236 r = begin_hints(cmd, policy);
1237 up_write(&cmd->root_lock);
1238
1239 return r;
1240}
1241
1242static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock,
1243 uint32_t hint)
1244{
1245 int r;
1246 __le32 value = cpu_to_le32(hint);
1247 __dm_bless_for_disk(&value);
1248
1249 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
1250 from_cblock(cblock), &value, &cmd->hint_root);
1251 cmd->changed = true;
1252
1253 return r;
1254}
1255
1256int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock,
1257 uint32_t hint)
1258{
1259 int r;
1260
1261 if (!hints_array_initialized(cmd))
1262 return 0;
1263
1264 down_write(&cmd->root_lock);
1265 r = save_hint(cmd, cblock, hint);
1266 up_write(&cmd->root_lock);
1267
1268 return r;
1269}
2ee57d58
JT		 1270
1271int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1272{
1273 return blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1274}
Linux 6.x block layer and io_uring tree(s)