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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
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};
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;
92
93 __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
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_oblock_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];
120 unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
121 size_t policy_hint_size;
122 struct dm_cache_statistics stats;
123
124 /*
125 * Reading the space map root can fail, so we read it into this
126 * buffer before the superblock is locked and updated.
127 */
128 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
129};
130
131/*-------------------------------------------------------------------
132 * superblock validator
133 *-----------------------------------------------------------------*/
134
135#define SUPERBLOCK_CSUM_XOR 9031977
136
137static void sb_prepare_for_write(struct dm_block_validator *v,
138 struct dm_block *b,
139 size_t sb_block_size)
140{
141 struct cache_disk_superblock *disk_super = dm_block_data(b);
142
143 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
144 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
145 sb_block_size - sizeof(__le32),
146 SUPERBLOCK_CSUM_XOR));
147}
148
149static int check_metadata_version(struct cache_disk_superblock *disk_super)
150{
151 uint32_t metadata_version = le32_to_cpu(disk_super->version);
152 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
153 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
154 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
155 return -EINVAL;
156 }
157
158 return 0;
159}
160
161static int sb_check(struct dm_block_validator *v,
162 struct dm_block *b,
163 size_t sb_block_size)
164{
165 struct cache_disk_superblock *disk_super = dm_block_data(b);
166 __le32 csum_le;
167
168 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
169 DMERR("sb_check failed: blocknr %llu: wanted %llu",
170 le64_to_cpu(disk_super->blocknr),
171 (unsigned long long)dm_block_location(b));
172 return -ENOTBLK;
173 }
174
175 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
176 DMERR("sb_check failed: magic %llu: wanted %llu",
177 le64_to_cpu(disk_super->magic),
178 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
179 return -EILSEQ;
180 }
181
182 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
183 sb_block_size - sizeof(__le32),
184 SUPERBLOCK_CSUM_XOR));
185 if (csum_le != disk_super->csum) {
186 DMERR("sb_check failed: csum %u: wanted %u",
187 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
188 return -EILSEQ;
189 }
190
191 return check_metadata_version(disk_super);
192}
193
194static struct dm_block_validator sb_validator = {
195 .name = "superblock",
196 .prepare_for_write = sb_prepare_for_write,
197 .check = sb_check
198};
199
200/*----------------------------------------------------------------*/
201
202static int superblock_read_lock(struct dm_cache_metadata *cmd,
203 struct dm_block **sblock)
204{
205 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
206 &sb_validator, sblock);
207}
208
209static int superblock_lock_zero(struct dm_cache_metadata *cmd,
210 struct dm_block **sblock)
211{
212 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
213 &sb_validator, sblock);
214}
215
216static int superblock_lock(struct dm_cache_metadata *cmd,
217 struct dm_block **sblock)
218{
219 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
220 &sb_validator, sblock);
221}
222
223/*----------------------------------------------------------------*/
224
225static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
226{
227 int r;
228 unsigned i;
229 struct dm_block *b;
230 __le64 *data_le, zero = cpu_to_le64(0);
231 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
232
233 /*
234 * We can't use a validator here - it may be all zeroes.
235 */
236 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
237 if (r)
238 return r;
239
240 data_le = dm_block_data(b);
241 *result = true;
242 for (i = 0; i < sb_block_size; i++) {
243 if (data_le[i] != zero) {
244 *result = false;
245 break;
246 }
247 }
248
249 return dm_bm_unlock(b);
250}
251
252static void __setup_mapping_info(struct dm_cache_metadata *cmd)
253{
254 struct dm_btree_value_type vt;
255
256 vt.context = NULL;
257 vt.size = sizeof(__le64);
258 vt.inc = NULL;
259 vt.dec = NULL;
260 vt.equal = NULL;
261 dm_array_info_init(&cmd->info, cmd->tm, &vt);
262
263 if (cmd->policy_hint_size) {
264 vt.size = sizeof(__le32);
265 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
266 }
267}
268
269static int __save_sm_root(struct dm_cache_metadata *cmd)
270{
271 int r;
272 size_t metadata_len;
273
274 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
275 if (r < 0)
276 return r;
277
278 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
279 metadata_len);
280}
281
282static void __copy_sm_root(struct dm_cache_metadata *cmd,
283 struct cache_disk_superblock *disk_super)
284{
285 memcpy(&disk_super->metadata_space_map_root,
286 &cmd->metadata_space_map_root,
287 sizeof(cmd->metadata_space_map_root));
288}
289
290static int __write_initial_superblock(struct dm_cache_metadata *cmd)
291{
292 int r;
293 struct dm_block *sblock;
294 struct cache_disk_superblock *disk_super;
295 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
296
297 /* FIXME: see if we can lose the max sectors limit */
298 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
299 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
300
301 r = dm_tm_pre_commit(cmd->tm);
302 if (r < 0)
303 return r;
304
305 /*
306 * dm_sm_copy_root() can fail. So we need to do it before we start
307 * updating the superblock.
308 */
309 r = __save_sm_root(cmd);
310 if (r)
311 return r;
312
313 r = superblock_lock_zero(cmd, &sblock);
314 if (r)
315 return r;
316
317 disk_super = dm_block_data(sblock);
318 disk_super->flags = 0;
319 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
320 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
321 disk_super->version = cpu_to_le32(MAX_CACHE_VERSION);
322 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
323 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
324 disk_super->policy_hint_size = 0;
325
326 __copy_sm_root(cmd, disk_super);
327
328 disk_super->mapping_root = cpu_to_le64(cmd->root);
329 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
330 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
331 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
332 disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks));
333 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
334 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
335 disk_super->cache_blocks = cpu_to_le32(0);
336
337 disk_super->read_hits = cpu_to_le32(0);
338 disk_super->read_misses = cpu_to_le32(0);
339 disk_super->write_hits = cpu_to_le32(0);
340 disk_super->write_misses = cpu_to_le32(0);
341
342 return dm_tm_commit(cmd->tm, sblock);
343}
344
345static int __format_metadata(struct dm_cache_metadata *cmd)
346{
347 int r;
348
349 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
350 &cmd->tm, &cmd->metadata_sm);
351 if (r < 0) {
352 DMERR("tm_create_with_sm failed");
353 return r;
354 }
355
356 __setup_mapping_info(cmd);
357
358 r = dm_array_empty(&cmd->info, &cmd->root);
359 if (r < 0)
360 goto bad;
361
362 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
363
364 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
365 if (r < 0)
366 goto bad;
367
368 cmd->discard_block_size = 0;
369 cmd->discard_nr_blocks = 0;
370
371 r = __write_initial_superblock(cmd);
372 if (r)
373 goto bad;
374
375 cmd->clean_when_opened = true;
376 return 0;
377
378bad:
379 dm_tm_destroy(cmd->tm);
380 dm_sm_destroy(cmd->metadata_sm);
381
382 return r;
383}
384
385static int __check_incompat_features(struct cache_disk_superblock *disk_super,
386 struct dm_cache_metadata *cmd)
387{
388 uint32_t features;
389
390 features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
391 if (features) {
392 DMERR("could not access metadata due to unsupported optional features (%lx).",
393 (unsigned long)features);
394 return -EINVAL;
395 }
396
397 /*
398 * Check for read-only metadata to skip the following RDWR checks.
399 */
400 if (get_disk_ro(cmd->bdev->bd_disk))
401 return 0;
402
403 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
404 if (features) {
405 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
406 (unsigned long)features);
407 return -EINVAL;
408 }
409
410 return 0;
411}
412
413static int __open_metadata(struct dm_cache_metadata *cmd)
414{
415 int r;
416 struct dm_block *sblock;
417 struct cache_disk_superblock *disk_super;
418 unsigned long sb_flags;
419
420 r = superblock_read_lock(cmd, &sblock);
421 if (r < 0) {
422 DMERR("couldn't read lock superblock");
423 return r;
424 }
425
426 disk_super = dm_block_data(sblock);
427
428 r = __check_incompat_features(disk_super, cmd);
429 if (r < 0)
430 goto bad;
431
432 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
433 disk_super->metadata_space_map_root,
434 sizeof(disk_super->metadata_space_map_root),
435 &cmd->tm, &cmd->metadata_sm);
436 if (r < 0) {
437 DMERR("tm_open_with_sm failed");
438 goto bad;
439 }
440
441 __setup_mapping_info(cmd);
442 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
443 sb_flags = le32_to_cpu(disk_super->flags);
444 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
445 return dm_bm_unlock(sblock);
446
447bad:
448 dm_bm_unlock(sblock);
449 return r;
450}
451
452static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
453 bool format_device)
454{
455 int r;
456 bool unformatted = false;
457
458 r = __superblock_all_zeroes(cmd->bm, &unformatted);
459 if (r)
460 return r;
461
462 if (unformatted)
463 return format_device ? __format_metadata(cmd) : -EPERM;
464
465 return __open_metadata(cmd);
466}
467
468static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
469 bool may_format_device)
470{
471 int r;
472 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE,
473 CACHE_METADATA_CACHE_SIZE,
474 CACHE_MAX_CONCURRENT_LOCKS);
475 if (IS_ERR(cmd->bm)) {
476 DMERR("could not create block manager");
477 return PTR_ERR(cmd->bm);
478 }
479
480 r = __open_or_format_metadata(cmd, may_format_device);
481 if (r)
482 dm_block_manager_destroy(cmd->bm);
483
484 return r;
485}
486
487static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
488{
489 dm_sm_destroy(cmd->metadata_sm);
490 dm_tm_destroy(cmd->tm);
491 dm_block_manager_destroy(cmd->bm);
492}
493
494typedef unsigned long (*flags_mutator)(unsigned long);
495
496static void update_flags(struct cache_disk_superblock *disk_super,
497 flags_mutator mutator)
498{
499 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
500 disk_super->flags = cpu_to_le32(sb_flags);
501}
502
503static unsigned long set_clean_shutdown(unsigned long flags)
504{
505 set_bit(CLEAN_SHUTDOWN, &flags);
506 return flags;
507}
508
509static unsigned long clear_clean_shutdown(unsigned long flags)
510{
511 clear_bit(CLEAN_SHUTDOWN, &flags);
512 return flags;
513}
514
515static void read_superblock_fields(struct dm_cache_metadata *cmd,
516 struct cache_disk_superblock *disk_super)
517{
518 cmd->root = le64_to_cpu(disk_super->mapping_root);
519 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
520 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
521 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
522 cmd->discard_nr_blocks = to_oblock(le64_to_cpu(disk_super->discard_nr_blocks));
523 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
524 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
525 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
526 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
527 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
528 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
529 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
530
531 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
532 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
533 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
534 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
535
536 cmd->changed = false;
537}
538
539/*
540 * The mutator updates the superblock flags.
541 */
542static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
543 flags_mutator mutator)
544{
545 int r;
546 struct cache_disk_superblock *disk_super;
547 struct dm_block *sblock;
548
549 r = superblock_lock(cmd, &sblock);
550 if (r)
551 return r;
552
553 disk_super = dm_block_data(sblock);
554 update_flags(disk_super, mutator);
555 read_superblock_fields(cmd, disk_super);
556 dm_bm_unlock(sblock);
557
558 return dm_bm_flush(cmd->bm);
559}
560
561static int __begin_transaction(struct dm_cache_metadata *cmd)
562{
563 int r;
564 struct cache_disk_superblock *disk_super;
565 struct dm_block *sblock;
566
567 /*
568 * We re-read the superblock every time. Shouldn't need to do this
569 * really.
570 */
571 r = superblock_read_lock(cmd, &sblock);
572 if (r)
573 return r;
574
575 disk_super = dm_block_data(sblock);
576 read_superblock_fields(cmd, disk_super);
577 dm_bm_unlock(sblock);
578
579 return 0;
580}
581
582static int __commit_transaction(struct dm_cache_metadata *cmd,
583 flags_mutator mutator)
584{
585 int r;
586 struct cache_disk_superblock *disk_super;
587 struct dm_block *sblock;
588
589 /*
590 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
591 */
592 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
593
594 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
595 &cmd->discard_root);
596 if (r)
597 return r;
598
599 r = dm_tm_pre_commit(cmd->tm);
600 if (r < 0)
601 return r;
602
603 r = __save_sm_root(cmd);
604 if (r)
605 return r;
606
607 r = superblock_lock(cmd, &sblock);
608 if (r)
609 return r;
610
611 disk_super = dm_block_data(sblock);
612
613 if (mutator)
614 update_flags(disk_super, mutator);
615
616 disk_super->mapping_root = cpu_to_le64(cmd->root);
617 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
618 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
619 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
620 disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks));
621 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
622 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
623 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
624 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
625 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
626
627 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
628 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
629 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
630 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
631 __copy_sm_root(cmd, disk_super);
632
633 return dm_tm_commit(cmd->tm, sblock);
634}
635
636/*----------------------------------------------------------------*/
637
638/*
639 * The mappings are held in a dm-array that has 64-bit values stored in
640 * little-endian format. The index is the cblock, the high 48bits of the
641 * value are the oblock and the low 16 bit the flags.
642 */
643#define FLAGS_MASK ((1 << 16) - 1)
644
645static __le64 pack_value(dm_oblock_t block, unsigned flags)
646{
647 uint64_t value = from_oblock(block);
648 value <<= 16;
649 value = value | (flags & FLAGS_MASK);
650 return cpu_to_le64(value);
651}
652
653static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
654{
655 uint64_t value = le64_to_cpu(value_le);
656 uint64_t b = value >> 16;
657 *block = to_oblock(b);
658 *flags = value & FLAGS_MASK;
659}
660
661/*----------------------------------------------------------------*/
662
663struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
664 sector_t data_block_size,
665 bool may_format_device,
666 size_t policy_hint_size)
667{
668 int r;
669 struct dm_cache_metadata *cmd;
670
671 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
672 if (!cmd) {
673 DMERR("could not allocate metadata struct");
674 return NULL;
675 }
676
677 init_rwsem(&cmd->root_lock);
678 cmd->bdev = bdev;
679 cmd->data_block_size = data_block_size;
680 cmd->cache_blocks = 0;
681 cmd->policy_hint_size = policy_hint_size;
682 cmd->changed = true;
683
684 r = __create_persistent_data_objects(cmd, may_format_device);
685 if (r) {
686 kfree(cmd);
687 return ERR_PTR(r);
688 }
689
690 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
691 if (r < 0) {
692 dm_cache_metadata_close(cmd);
693 return ERR_PTR(r);
694 }
695
696 return cmd;
697}
698
699void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
700{
701 __destroy_persistent_data_objects(cmd);
702 kfree(cmd);
703}
704
705/*
706 * Checks that the given cache block is either unmapped or clean.
707 */
708static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
709 bool *result)
710{
711 int r;
712 __le64 value;
713 dm_oblock_t ob;
714 unsigned flags;
715
716 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
717 if (r) {
718 DMERR("block_unmapped_or_clean failed");
719 return r;
720 }
721
722 unpack_value(value, &ob, &flags);
723 *result = !((flags & M_VALID) && (flags & M_DIRTY));
724
725 return 0;
726}
727
728static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
729 dm_cblock_t begin, dm_cblock_t end,
730 bool *result)
731{
732 int r;
733 *result = true;
734
735 while (begin != end) {
736 r = block_unmapped_or_clean(cmd, begin, result);
737 if (r)
738 return r;
739
740 if (!*result) {
741 DMERR("cache block %llu is dirty",
742 (unsigned long long) from_cblock(begin));
743 return 0;
744 }
745
746 begin = to_cblock(from_cblock(begin) + 1);
747 }
748
749 return 0;
750}
751
752int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
753{
754 int r;
755 bool clean;
756 __le64 null_mapping = pack_value(0, 0);
757
758 down_write(&cmd->root_lock);
759 __dm_bless_for_disk(&null_mapping);
760
761 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
762 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
763 if (r) {
764 __dm_unbless_for_disk(&null_mapping);
765 goto out;
766 }
767
768 if (!clean) {
769 DMERR("unable to shrink cache due to dirty blocks");
770 r = -EINVAL;
771 __dm_unbless_for_disk(&null_mapping);
772 goto out;
773 }
774 }
775
776 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
777 from_cblock(new_cache_size),
778 &null_mapping, &cmd->root);
779 if (!r)
780 cmd->cache_blocks = new_cache_size;
781 cmd->changed = true;
782
783out:
784 up_write(&cmd->root_lock);
785
786 return r;
787}
788
789int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
790 sector_t discard_block_size,
791 dm_oblock_t new_nr_entries)
792{
793 int r;
794
795 down_write(&cmd->root_lock);
796 r = dm_bitset_resize(&cmd->discard_info,
797 cmd->discard_root,
798 from_oblock(cmd->discard_nr_blocks),
799 from_oblock(new_nr_entries),
800 false, &cmd->discard_root);
801 if (!r) {
802 cmd->discard_block_size = discard_block_size;
803 cmd->discard_nr_blocks = new_nr_entries;
804 }
805
806 cmd->changed = true;
807 up_write(&cmd->root_lock);
808
809 return r;
810}
811
812static int __set_discard(struct dm_cache_metadata *cmd, dm_oblock_t b)
813{
814 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
815 from_oblock(b), &cmd->discard_root);
816}
817
818static int __clear_discard(struct dm_cache_metadata *cmd, dm_oblock_t b)
819{
820 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
821 from_oblock(b), &cmd->discard_root);
822}
823
824static int __is_discarded(struct dm_cache_metadata *cmd, dm_oblock_t b,
825 bool *is_discarded)
826{
827 return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
828 from_oblock(b), &cmd->discard_root,
829 is_discarded);
830}
831
832static int __discard(struct dm_cache_metadata *cmd,
833 dm_oblock_t dblock, bool discard)
834{
835 int r;
836
837 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
838 if (r)
839 return r;
840
841 cmd->changed = true;
842 return 0;
843}
844
845int dm_cache_set_discard(struct dm_cache_metadata *cmd,
846 dm_oblock_t dblock, bool discard)
847{
848 int r;
849
850 down_write(&cmd->root_lock);
851 r = __discard(cmd, dblock, discard);
852 up_write(&cmd->root_lock);
853
854 return r;
855}
856
857static int __load_discards(struct dm_cache_metadata *cmd,
858 load_discard_fn fn, void *context)
859{
860 int r = 0;
861 dm_block_t b;
862 bool discard;
863
864 for (b = 0; b < from_oblock(cmd->discard_nr_blocks); b++) {
865 dm_oblock_t dblock = to_oblock(b);
866
867 if (cmd->clean_when_opened) {
868 r = __is_discarded(cmd, dblock, &discard);
869 if (r)
870 return r;
871 } else
872 discard = false;
873
874 r = fn(context, cmd->discard_block_size, dblock, discard);
875 if (r)
876 break;
877 }
878
879 return r;
880}
881
882int dm_cache_load_discards(struct dm_cache_metadata *cmd,
883 load_discard_fn fn, void *context)
884{
885 int r;
886
887 down_read(&cmd->root_lock);
888 r = __load_discards(cmd, fn, context);
889 up_read(&cmd->root_lock);
890
891 return r;
892}
893
894dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd)
895{
896 dm_cblock_t r;
897
898 down_read(&cmd->root_lock);
899 r = cmd->cache_blocks;
900 up_read(&cmd->root_lock);
901
902 return r;
903}
904
905static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
906{
907 int r;
908 __le64 value = pack_value(0, 0);
909
910 __dm_bless_for_disk(&value);
911 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
912 &value, &cmd->root);
913 if (r)
914 return r;
915
916 cmd->changed = true;
917 return 0;
918}
919
920int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
921{
922 int r;
923
924 down_write(&cmd->root_lock);
925 r = __remove(cmd, cblock);
926 up_write(&cmd->root_lock);
927
928 return r;
929}
930
931static int __insert(struct dm_cache_metadata *cmd,
932 dm_cblock_t cblock, dm_oblock_t oblock)
933{
934 int r;
935 __le64 value = pack_value(oblock, M_VALID);
936 __dm_bless_for_disk(&value);
937
938 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
939 &value, &cmd->root);
940 if (r)
941 return r;
942
943 cmd->changed = true;
944 return 0;
945}
946
947int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
948 dm_cblock_t cblock, dm_oblock_t oblock)
949{
950 int r;
951
952 down_write(&cmd->root_lock);
953 r = __insert(cmd, cblock, oblock);
954 up_write(&cmd->root_lock);
955
956 return r;
957}
958
959struct thunk {
960 load_mapping_fn fn;
961 void *context;
962
963 struct dm_cache_metadata *cmd;
964 bool respect_dirty_flags;
965 bool hints_valid;
966};
967
968static bool policy_unchanged(struct dm_cache_metadata *cmd,
969 struct dm_cache_policy *policy)
970{
971 const char *policy_name = dm_cache_policy_get_name(policy);
972 const unsigned *policy_version = dm_cache_policy_get_version(policy);
973 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
974
975 /*
976 * Ensure policy names match.
977 */
978 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
979 return false;
980
981 /*
982 * Ensure policy major versions match.
983 */
984 if (cmd->policy_version[0] != policy_version[0])
985 return false;
986
987 /*
988 * Ensure policy hint sizes match.
989 */
990 if (cmd->policy_hint_size != policy_hint_size)
991 return false;
992
993 return true;
994}
995
996static bool hints_array_initialized(struct dm_cache_metadata *cmd)
997{
998 return cmd->hint_root && cmd->policy_hint_size;
999}
1000
1001static bool hints_array_available(struct dm_cache_metadata *cmd,
1002 struct dm_cache_policy *policy)
1003{
1004 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1005 hints_array_initialized(cmd);
1006}
1007
1008static int __load_mapping(void *context, uint64_t cblock, void *leaf)
1009{
1010 int r = 0;
1011 bool dirty;
1012 __le64 value;
1013 __le32 hint_value = 0;
1014 dm_oblock_t oblock;
1015 unsigned flags;
1016 struct thunk *thunk = context;
1017 struct dm_cache_metadata *cmd = thunk->cmd;
1018
1019 memcpy(&value, leaf, sizeof(value));
1020 unpack_value(value, &oblock, &flags);
1021
1022 if (flags & M_VALID) {
1023 if (thunk->hints_valid) {
1024 r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,
1025 cblock, &hint_value);
1026 if (r && r != -ENODATA)
1027 return r;
1028 }
1029
1030 dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;
1031 r = thunk->fn(thunk->context, oblock, to_cblock(cblock),
1032 dirty, le32_to_cpu(hint_value), thunk->hints_valid);
1033 }
1034
1035 return r;
1036}
1037
1038static int __load_mappings(struct dm_cache_metadata *cmd,
1039 struct dm_cache_policy *policy,
1040 load_mapping_fn fn, void *context)
1041{
1042 struct thunk thunk;
1043
1044 thunk.fn = fn;
1045 thunk.context = context;
1046
1047 thunk.cmd = cmd;
1048 thunk.respect_dirty_flags = cmd->clean_when_opened;
1049 thunk.hints_valid = hints_array_available(cmd, policy);
1050
1051 return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);
1052}
1053
1054int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1055 struct dm_cache_policy *policy,
1056 load_mapping_fn fn, void *context)
1057{
1058 int r;
1059
1060 down_read(&cmd->root_lock);
1061 r = __load_mappings(cmd, policy, fn, context);
1062 up_read(&cmd->root_lock);
1063
1064 return r;
1065}
1066
1067static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1068{
1069 int r = 0;
1070 __le64 value;
1071 dm_oblock_t oblock;
1072 unsigned flags;
1073
1074 memcpy(&value, leaf, sizeof(value));
1075 unpack_value(value, &oblock, &flags);
1076
1077 return r;
1078}
1079
1080static int __dump_mappings(struct dm_cache_metadata *cmd)
1081{
1082 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1083}
1084
1085void dm_cache_dump(struct dm_cache_metadata *cmd)
1086{
1087 down_read(&cmd->root_lock);
1088 __dump_mappings(cmd);
1089 up_read(&cmd->root_lock);
1090}
1091
1092int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1093{
1094 int r;
1095
1096 down_read(&cmd->root_lock);
1097 r = cmd->changed;
1098 up_read(&cmd->root_lock);
1099
1100 return r;
1101}
1102
1103static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1104{
1105 int r;
1106 unsigned flags;
1107 dm_oblock_t oblock;
1108 __le64 value;
1109
1110 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1111 if (r)
1112 return r;
1113
1114 unpack_value(value, &oblock, &flags);
1115
1116 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1117 /* nothing to be done */
1118 return 0;
1119
1120 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1121 __dm_bless_for_disk(&value);
1122
1123 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1124 &value, &cmd->root);
1125 if (r)
1126 return r;
1127
1128 cmd->changed = true;
1129 return 0;
1130
1131}
1132
1133int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
1134 dm_cblock_t cblock, bool dirty)
1135{
1136 int r;
1137
1138 down_write(&cmd->root_lock);
1139 r = __dirty(cmd, cblock, dirty);
1140 up_write(&cmd->root_lock);
1141
1142 return r;
1143}
1144
1145void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1146 struct dm_cache_statistics *stats)
1147{
1148 down_read(&cmd->root_lock);
1149 *stats = cmd->stats;
1150 up_read(&cmd->root_lock);
1151}
1152
1153void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1154 struct dm_cache_statistics *stats)
1155{
1156 down_write(&cmd->root_lock);
1157 cmd->stats = *stats;
1158 up_write(&cmd->root_lock);
1159}
1160
1161int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1162{
1163 int r;
1164 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1165 clear_clean_shutdown);
1166
1167 down_write(&cmd->root_lock);
1168 r = __commit_transaction(cmd, mutator);
1169 if (r)
1170 goto out;
1171
1172 r = __begin_transaction(cmd);
1173
1174out:
1175 up_write(&cmd->root_lock);
1176 return r;
1177}
1178
1179int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1180 dm_block_t *result)
1181{
1182 int r = -EINVAL;
1183
1184 down_read(&cmd->root_lock);
1185 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1186 up_read(&cmd->root_lock);
1187
1188 return r;
1189}
1190
1191int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1192 dm_block_t *result)
1193{
1194 int r = -EINVAL;
1195
1196 down_read(&cmd->root_lock);
1197 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1198 up_read(&cmd->root_lock);
1199
1200 return r;
1201}
1202
1203/*----------------------------------------------------------------*/
1204
1205static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1206{
1207 int r;
1208 __le32 value;
1209 size_t hint_size;
1210 const char *policy_name = dm_cache_policy_get_name(policy);
1211 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1212
1213 if (!policy_name[0] ||
1214 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1215 return -EINVAL;
1216
1217 if (!policy_unchanged(cmd, policy)) {
1218 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1219 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1220
1221 hint_size = dm_cache_policy_get_hint_size(policy);
1222 if (!hint_size)
1223 return 0; /* short-circuit hints initialization */
1224 cmd->policy_hint_size = hint_size;
1225
1226 if (cmd->hint_root) {
1227 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1228 if (r)
1229 return r;
1230 }
1231
1232 r = dm_array_empty(&cmd->hint_info, &cmd->hint_root);
1233 if (r)
1234 return r;
1235
1236 value = cpu_to_le32(0);
1237 __dm_bless_for_disk(&value);
1238 r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0,
1239 from_cblock(cmd->cache_blocks),
1240 &value, &cmd->hint_root);
1241 if (r)
1242 return r;
1243 }
1244
1245 return 0;
1246}
1247
1248static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, uint32_t hint)
1249{
1250 struct dm_cache_metadata *cmd = context;
1251 __le32 value = cpu_to_le32(hint);
1252 int r;
1253
1254 __dm_bless_for_disk(&value);
1255
1256 r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
1257 from_cblock(cblock), &value, &cmd->hint_root);
1258 cmd->changed = true;
1259
1260 return r;
1261}
1262
1263static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1264{
1265 int r;
1266
1267 r = begin_hints(cmd, policy);
1268 if (r) {
1269 DMERR("begin_hints failed");
1270 return r;
1271 }
1272
1273 return policy_walk_mappings(policy, save_hint, cmd);
1274}
1275
1276int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1277{
1278 int r;
1279
1280 down_write(&cmd->root_lock);
1281 r = write_hints(cmd, policy);
1282 up_write(&cmd->root_lock);
1283
1284 return r;
1285}
1286
1287int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1288{
1289 return blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1290}