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dm transaction manager: fix corruption due to non-atomic transaction commit
[deliverable/linux.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;
64ab346a 112 dm_oblock_t discard_nr_blocks;
c6b4fcba
JT		 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);
64ab346a 305 disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks));
c6b4fcba
JT		 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);
64ab346a 499 cmd->discard_nr_blocks = to_oblock(le64_to_cpu(disk_super->discard_nr_blocks));
c6b4fcba
JT		 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);
a9d45396 533 dm_bm_unlock(sblock);
c6b4fcba 534
a9d45396 535 return dm_bm_flush(cmd->bm);
c6b4fcba
JT		 536}
537
538static int __begin_transaction(struct dm_cache_metadata *cmd)
539{
540 int r;
541 struct cache_disk_superblock *disk_super;
542 struct dm_block *sblock;
543
544 /*
545 * We re-read the superblock every time. Shouldn't need to do this
546 * really.
547 */
548 r = superblock_read_lock(cmd, &sblock);
549 if (r)
550 return r;
551
552 disk_super = dm_block_data(sblock);
553 read_superblock_fields(cmd, disk_super);
554 dm_bm_unlock(sblock);
555
556 return 0;
557}
558
559static int __commit_transaction(struct dm_cache_metadata *cmd,
560 flags_mutator mutator)
561{
562 int r;
563 size_t metadata_len;
564 struct cache_disk_superblock *disk_super;
565 struct dm_block *sblock;
566
567 /*
568 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
569 */
570 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
571
572 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
573 &cmd->discard_root);
574 if (r)
575 return r;
576
577 r = dm_tm_pre_commit(cmd->tm);
578 if (r < 0)
579 return r;
580
581 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
582 if (r < 0)
583 return r;
584
585 r = superblock_lock(cmd, &sblock);
586 if (r)
587 return r;
588
589 disk_super = dm_block_data(sblock);
590
591 if (mutator)
592 update_flags(disk_super, mutator);
593
594 disk_super->mapping_root = cpu_to_le64(cmd->root);
595 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
596 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
597 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
64ab346a 598 disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks));
c6b4fcba
JT		 599 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
600 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
4e7f506f
MS		 601 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
602 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
603 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
c6b4fcba
JT		 604
605 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
606 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
607 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
608 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
609
610 r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
611 metadata_len);
612 if (r < 0) {
613 dm_bm_unlock(sblock);
614 return r;
615 }
616
617 return dm_tm_commit(cmd->tm, sblock);
618}
619
620/*----------------------------------------------------------------*/
621
622/*
623 * The mappings are held in a dm-array that has 64-bit values stored in
624 * little-endian format. The index is the cblock, the high 48bits of the
625 * value are the oblock and the low 16 bit the flags.
626 */
627#define FLAGS_MASK ((1 << 16) - 1)
628
629static __le64 pack_value(dm_oblock_t block, unsigned flags)
630{
631 uint64_t value = from_oblock(block);
632 value <<= 16;
633 value = value | (flags & FLAGS_MASK);
634 return cpu_to_le64(value);
635}
636
637static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
638{
639 uint64_t value = le64_to_cpu(value_le);
640 uint64_t b = value >> 16;
641 *block = to_oblock(b);
642 *flags = value & FLAGS_MASK;
643}
644
645/*----------------------------------------------------------------*/
646
647struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
648 sector_t data_block_size,
649 bool may_format_device,
650 size_t policy_hint_size)
651{
652 int r;
653 struct dm_cache_metadata *cmd;
654
655 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
656 if (!cmd) {
657 DMERR("could not allocate metadata struct");
658 return NULL;
659 }
660
661 init_rwsem(&cmd->root_lock);
662 cmd->bdev = bdev;
663 cmd->data_block_size = data_block_size;
664 cmd->cache_blocks = 0;
665 cmd->policy_hint_size = policy_hint_size;
666 cmd->changed = true;
667
668 r = __create_persistent_data_objects(cmd, may_format_device);
669 if (r) {
670 kfree(cmd);
671 return ERR_PTR(r);
672 }
673
674 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
675 if (r < 0) {
676 dm_cache_metadata_close(cmd);
677 return ERR_PTR(r);
678 }
679
680 return cmd;
681}
682
683void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
684{
685 __destroy_persistent_data_objects(cmd);
686 kfree(cmd);
687}
688
f494a9c6
JT		 689/*
690 * Checks that the given cache block is either unmapped or clean.
691 */
692static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
693 bool *result)
694{
695 int r;
696 __le64 value;
697 dm_oblock_t ob;
698 unsigned flags;
699
700 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
701 if (r) {
702 DMERR("block_unmapped_or_clean failed");
703 return r;
704 }
705
706 unpack_value(value, &ob, &flags);
707 *result = !((flags & M_VALID) && (flags & M_DIRTY));
708
709 return 0;
710}
711
712static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
713 dm_cblock_t begin, dm_cblock_t end,
714 bool *result)
715{
716 int r;
717 *result = true;
718
719 while (begin != end) {
720 r = block_unmapped_or_clean(cmd, begin, result);
721 if (r)
722 return r;
723
724 if (!*result) {
725 DMERR("cache block %llu is dirty",
726 (unsigned long long) from_cblock(begin));
727 return 0;
728 }
729
730 begin = to_cblock(from_cblock(begin) + 1);
731 }
732
733 return 0;
734}
735
c6b4fcba
JT		 736int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
737{
738 int r;
f494a9c6 739 bool clean;
c6b4fcba
JT		 740 __le64 null_mapping = pack_value(0, 0);
741
742 down_write(&cmd->root_lock);
743 __dm_bless_for_disk(&null_mapping);
f494a9c6
JT		 744
745 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
746 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
747 if (r) {
748 __dm_unbless_for_disk(&null_mapping);
749 goto out;
750 }
751
752 if (!clean) {
753 DMERR("unable to shrink cache due to dirty blocks");
754 r = -EINVAL;
755 __dm_unbless_for_disk(&null_mapping);
756 goto out;
757 }
758 }
759
c6b4fcba
JT		 760 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
761 from_cblock(new_cache_size),
762 &null_mapping, &cmd->root);
763 if (!r)
764 cmd->cache_blocks = new_cache_size;
765 cmd->changed = true;
f494a9c6
JT		 766
767out:
c6b4fcba
JT		 768 up_write(&cmd->root_lock);
769
770 return r;
771}
772
773int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
774 sector_t discard_block_size,
64ab346a 775 dm_oblock_t new_nr_entries)
c6b4fcba
JT		 776{
777 int r;
778
779 down_write(&cmd->root_lock);
780 r = dm_bitset_resize(&cmd->discard_info,
781 cmd->discard_root,
64ab346a
HM		 782 from_oblock(cmd->discard_nr_blocks),
783 from_oblock(new_nr_entries),
c6b4fcba
JT		 784 false, &cmd->discard_root);
785 if (!r) {
786 cmd->discard_block_size = discard_block_size;
787 cmd->discard_nr_blocks = new_nr_entries;
788 }
789
790 cmd->changed = true;
791 up_write(&cmd->root_lock);
792
793 return r;
794}
795
64ab346a 796static int __set_discard(struct dm_cache_metadata *cmd, dm_oblock_t b)
c6b4fcba
JT		 797{
798 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
64ab346a 799 from_oblock(b), &cmd->discard_root);
c6b4fcba
JT		 800}
801
64ab346a 802static int __clear_discard(struct dm_cache_metadata *cmd, dm_oblock_t b)
c6b4fcba
JT		 803{
804 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
64ab346a 805 from_oblock(b), &cmd->discard_root);
c6b4fcba
JT		 806}
807
64ab346a 808static int __is_discarded(struct dm_cache_metadata *cmd, dm_oblock_t b,
c6b4fcba
JT		 809 bool *is_discarded)
810{
811 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
64ab346a 812 from_oblock(b), &cmd->discard_root,
c6b4fcba
JT		 813 is_discarded);
814}
815
816static int __discard(struct dm_cache_metadata *cmd,
64ab346a 817 dm_oblock_t dblock, bool discard)
c6b4fcba
JT		 818{
819 int r;
820
821 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
822 if (r)
823 return r;
824
825 cmd->changed = true;
826 return 0;
827}
828
829int dm_cache_set_discard(struct dm_cache_metadata *cmd,
64ab346a 830 dm_oblock_t dblock, bool discard)
c6b4fcba
JT		 831{
832 int r;
833
834 down_write(&cmd->root_lock);
835 r = __discard(cmd, dblock, discard);
836 up_write(&cmd->root_lock);
837
838 return r;
839}
840
841static int __load_discards(struct dm_cache_metadata *cmd,
842 load_discard_fn fn, void *context)
843{
844 int r = 0;
845 dm_block_t b;
846 bool discard;
847
64ab346a
HM		 848 for (b = 0; b < from_oblock(cmd->discard_nr_blocks); b++) {
849 dm_oblock_t dblock = to_oblock(b);
c6b4fcba
JT		 850
851 if (cmd->clean_when_opened) {
852 r = __is_discarded(cmd, dblock, &discard);
853 if (r)
854 return r;
855 } else
856 discard = false;
857
858 r = fn(context, cmd->discard_block_size, dblock, discard);
859 if (r)
860 break;
861 }
862
863 return r;
864}
865
866int dm_cache_load_discards(struct dm_cache_metadata *cmd,
867 load_discard_fn fn, void *context)
868{
869 int r;
870
871 down_read(&cmd->root_lock);
872 r = __load_discards(cmd, fn, context);
873 up_read(&cmd->root_lock);
874
875 return r;
876}
877
878dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd)
879{
880 dm_cblock_t r;
881
882 down_read(&cmd->root_lock);
883 r = cmd->cache_blocks;
884 up_read(&cmd->root_lock);
885
886 return r;
887}
888
889static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
890{
891 int r;
892 __le64 value = pack_value(0, 0);
893
894 __dm_bless_for_disk(&value);
895 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
896 &value, &cmd->root);
897 if (r)
898 return r;
899
900 cmd->changed = true;
901 return 0;
902}
903
904int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
905{
906 int r;
907
908 down_write(&cmd->root_lock);
909 r = __remove(cmd, cblock);
910 up_write(&cmd->root_lock);
911
912 return r;
913}
914
915static int __insert(struct dm_cache_metadata *cmd,
916 dm_cblock_t cblock, dm_oblock_t oblock)
917{
918 int r;
919 __le64 value = pack_value(oblock, M_VALID);
920 __dm_bless_for_disk(&value);
921
922 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
923 &value, &cmd->root);
924 if (r)
925 return r;
926
927 cmd->changed = true;
928 return 0;
929}
930
931int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
932 dm_cblock_t cblock, dm_oblock_t oblock)
933{
934 int r;
935
936 down_write(&cmd->root_lock);
937 r = __insert(cmd, cblock, oblock);
938 up_write(&cmd->root_lock);
939
940 return r;
941}
942
943struct thunk {
944 load_mapping_fn fn;
945 void *context;
946
947 struct dm_cache_metadata *cmd;
948 bool respect_dirty_flags;
949 bool hints_valid;
950};
951
ea2dd8c1
MS		 952static bool policy_unchanged(struct dm_cache_metadata *cmd,
953 struct dm_cache_policy *policy)
954{
955 const char *policy_name = dm_cache_policy_get_name(policy);
956 const unsigned *policy_version = dm_cache_policy_get_version(policy);
957 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
958
959 /*
960 * Ensure policy names match.
961 */
962 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
963 return false;
964
965 /*
966 * Ensure policy major versions match.
967 */
968 if (cmd->policy_version[0] != policy_version[0])
969 return false;
970
971 /*
972 * Ensure policy hint sizes match.
973 */
974 if (cmd->policy_hint_size != policy_hint_size)
975 return false;
976
977 return true;
978}
979
c6b4fcba
JT		 980static bool hints_array_initialized(struct dm_cache_metadata *cmd)
981{
982 return cmd->hint_root && cmd->policy_hint_size;
983}
984
985static bool hints_array_available(struct dm_cache_metadata *cmd,
ea2dd8c1 986 struct dm_cache_policy *policy)
c6b4fcba 987{
ea2dd8c1 988 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
c6b4fcba
JT		 989 hints_array_initialized(cmd);
990}
991
992static int __load_mapping(void *context, uint64_t cblock, void *leaf)
993{
994 int r = 0;
995 bool dirty;
996 __le64 value;
997 __le32 hint_value = 0;
998 dm_oblock_t oblock;
999 unsigned flags;
1000 struct thunk *thunk = context;
1001 struct dm_cache_metadata *cmd = thunk->cmd;
1002
1003 memcpy(&value, leaf, sizeof(value));
1004 unpack_value(value, &oblock, &flags);
1005
1006 if (flags & M_VALID) {
1007 if (thunk->hints_valid) {
1008 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,
1009 cblock, &hint_value);
1010 if (r && r != -ENODATA)
1011 return r;
1012 }
1013
1014 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;
1015 r = thunk->fn(thunk->context, oblock, to_cblock(cblock),
1016 dirty, le32_to_cpu(hint_value), thunk->hints_valid);
1017 }
1018
1019 return r;
1020}
1021
ea2dd8c1
MS		 1022static int __load_mappings(struct dm_cache_metadata *cmd,
1023 struct dm_cache_policy *policy,
c6b4fcba
JT		 1024 load_mapping_fn fn, void *context)
1025{
1026 struct thunk thunk;
1027
1028 thunk.fn = fn;
1029 thunk.context = context;
1030
1031 thunk.cmd = cmd;
1032 thunk.respect_dirty_flags = cmd->clean_when_opened;
ea2dd8c1 1033 thunk.hints_valid = hints_array_available(cmd, policy);
c6b4fcba
JT		 1034
1035 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);
1036}
1037
ea2dd8c1
MS		 1038int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1039 struct dm_cache_policy *policy,
c6b4fcba
JT		 1040 load_mapping_fn fn, void *context)
1041{
1042 int r;
1043
1044 down_read(&cmd->root_lock);
ea2dd8c1 1045 r = __load_mappings(cmd, policy, fn, context);
c6b4fcba
JT		 1046 up_read(&cmd->root_lock);
1047
1048 return r;
1049}
1050
1051static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1052{
1053 int r = 0;
1054 __le64 value;
1055 dm_oblock_t oblock;
1056 unsigned flags;
1057
1058 memcpy(&value, leaf, sizeof(value));
1059 unpack_value(value, &oblock, &flags);
1060
1061 return r;
1062}
1063
1064static int __dump_mappings(struct dm_cache_metadata *cmd)
1065{
1066 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1067}
1068
1069void dm_cache_dump(struct dm_cache_metadata *cmd)
1070{
1071 down_read(&cmd->root_lock);
1072 __dump_mappings(cmd);
1073 up_read(&cmd->root_lock);
1074}
1075
1076int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1077{
1078 int r;
1079
1080 down_read(&cmd->root_lock);
1081 r = cmd->changed;
1082 up_read(&cmd->root_lock);
1083
1084 return r;
1085}
1086
1087static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1088{
1089 int r;
1090 unsigned flags;
1091 dm_oblock_t oblock;
1092 __le64 value;
1093
1094 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1095 if (r)
1096 return r;
1097
1098 unpack_value(value, &oblock, &flags);
1099
1100 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1101 /* nothing to be done */
1102 return 0;
1103
79ed9caf 1104 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
c6b4fcba
JT		 1105 __dm_bless_for_disk(&value);
1106
1107 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1108 &value, &cmd->root);
1109 if (r)
1110 return r;
1111
1112 cmd->changed = true;
1113 return 0;
1114
1115}
1116
1117int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
1118 dm_cblock_t cblock, bool dirty)
1119{
1120 int r;
1121
1122 down_write(&cmd->root_lock);
1123 r = __dirty(cmd, cblock, dirty);
1124 up_write(&cmd->root_lock);
1125
1126 return r;
1127}
1128
1129void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1130 struct dm_cache_statistics *stats)
1131{
1132 down_read(&cmd->root_lock);
8c5008fa 1133 *stats = cmd->stats;
c6b4fcba
JT		 1134 up_read(&cmd->root_lock);
1135}
1136
1137void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1138 struct dm_cache_statistics *stats)
1139{
1140 down_write(&cmd->root_lock);
8c5008fa 1141 cmd->stats = *stats;
c6b4fcba
JT		 1142 up_write(&cmd->root_lock);
1143}
1144
1145int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1146{
1147 int r;
1148 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1149 clear_clean_shutdown);
1150
1151 down_write(&cmd->root_lock);
1152 r = __commit_transaction(cmd, mutator);
1153 if (r)
1154 goto out;
1155
1156 r = __begin_transaction(cmd);
1157
1158out:
1159 up_write(&cmd->root_lock);
1160 return r;
1161}
1162
1163int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1164 dm_block_t *result)
1165{
1166 int r = -EINVAL;
1167
1168 down_read(&cmd->root_lock);
1169 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1170 up_read(&cmd->root_lock);
1171
1172 return r;
1173}
1174
1175int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1176 dm_block_t *result)
1177{
1178 int r = -EINVAL;
1179
1180 down_read(&cmd->root_lock);
1181 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1182 up_read(&cmd->root_lock);
1183
1184 return r;
1185}
1186
1187/*----------------------------------------------------------------*/
1188
1189static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1190{
1191 int r;
1192 __le32 value;
1193 size_t hint_size;
1194 const char *policy_name = dm_cache_policy_get_name(policy);
4e7f506f 1195 const unsigned *policy_version = dm_cache_policy_get_version(policy);
c6b4fcba
JT		 1196
1197 if (!policy_name[0] ||
1198 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1199 return -EINVAL;
1200
ea2dd8c1 1201 if (!policy_unchanged(cmd, policy)) {
c6b4fcba 1202 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
4e7f506f 1203 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
c6b4fcba
JT		 1204
1205 hint_size = dm_cache_policy_get_hint_size(policy);
1206 if (!hint_size)
1207 return 0; /* short-circuit hints initialization */
1208 cmd->policy_hint_size = hint_size;
1209
1210 if (cmd->hint_root) {
1211 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1212 if (r)
1213 return r;
1214 }
1215
1216 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root);
1217 if (r)
1218 return r;
1219
1220 value = cpu_to_le32(0);
1221 __dm_bless_for_disk(&value);
1222 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0,
1223 from_cblock(cmd->cache_blocks),
1224 &value, &cmd->hint_root);
1225 if (r)
1226 return r;
1227 }
1228
1229 return 0;
1230}
1231
1232int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1233{
1234 int r;
1235
1236 down_write(&cmd->root_lock);
1237 r = begin_hints(cmd, policy);
1238 up_write(&cmd->root_lock);
1239
1240 return r;
1241}
1242
1243static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock,
1244 uint32_t hint)
1245{
1246 int r;
1247 __le32 value = cpu_to_le32(hint);
1248 __dm_bless_for_disk(&value);
1249
1250 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
1251 from_cblock(cblock), &value, &cmd->hint_root);
1252 cmd->changed = true;
1253
1254 return r;
1255}
1256
1257int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock,
1258 uint32_t hint)
1259{
1260 int r;
1261
1262 if (!hints_array_initialized(cmd))
1263 return 0;
1264
1265 down_write(&cmd->root_lock);
1266 r = save_hint(cmd, cblock, hint);
1267 up_write(&cmd->root_lock);
1268
1269 return r;
1270}
2ee57d58
JT		 1271
1272int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1273{
1274 return blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1275}
Linux kernel - Deliverables
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