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Merge tag 'iio-for-4.12d' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23...
[linux-2.6/btrfs-unstable.git] / drivers / md / dm-cache-metadata.c
blob6735c8d6a44551a6dd9cc25fa9b505316bfde060
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 2
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
39 enum superblock_flag_bits {
40 /* for spotting crashes that would invalidate the dirty bitset */
41 CLEAN_SHUTDOWN,
42 /* metadata must be checked using the tools */
43 NEEDS_CHECK,
44 };
45
46 /*
47 * Each mapping from cache block -> origin block carries a set of flags.
48 */
49 enum mapping_bits {
50 /*
51 * A valid mapping. Because we're using an array we clear this
52 * flag for an non existant mapping.
53 */
54 M_VALID = 1,
55
56 /*
57 * The data on the cache is different from that on the origin.
58 * This flag is only used by metadata format 1.
59 */
60 M_DIRTY = 2
61 };
62
63 struct cache_disk_superblock {
64 __le32 csum;
65 __le32 flags;
66 __le64 blocknr;
67
68 __u8 uuid[16];
69 __le64 magic;
70 __le32 version;
71
72 __u8 policy_name[CACHE_POLICY_NAME_SIZE];
73 __le32 policy_hint_size;
74
75 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
76 __le64 mapping_root;
77 __le64 hint_root;
78
79 __le64 discard_root;
80 __le64 discard_block_size;
81 __le64 discard_nr_blocks;
82
83 __le32 data_block_size;
84 __le32 metadata_block_size;
85 __le32 cache_blocks;
86
87 __le32 compat_flags;
88 __le32 compat_ro_flags;
89 __le32 incompat_flags;
90
91 __le32 read_hits;
92 __le32 read_misses;
93 __le32 write_hits;
94 __le32 write_misses;
95
96 __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
97
98 /*
99 * Metadata format 2 fields.
100 */
101 __le64 dirty_root;
102 } __packed;
103
104 struct dm_cache_metadata {
105 atomic_t ref_count;
106 struct list_head list;
107
108 unsigned version;
109 struct block_device *bdev;
110 struct dm_block_manager *bm;
111 struct dm_space_map *metadata_sm;
112 struct dm_transaction_manager *tm;
113
114 struct dm_array_info info;
115 struct dm_array_info hint_info;
116 struct dm_disk_bitset discard_info;
117
118 struct rw_semaphore root_lock;
119 unsigned long flags;
120 dm_block_t root;
121 dm_block_t hint_root;
122 dm_block_t discard_root;
123
124 sector_t discard_block_size;
125 dm_dblock_t discard_nr_blocks;
126
127 sector_t data_block_size;
128 dm_cblock_t cache_blocks;
129 bool changed:1;
130 bool clean_when_opened:1;
131
132 char policy_name[CACHE_POLICY_NAME_SIZE];
133 unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
134 size_t policy_hint_size;
135 struct dm_cache_statistics stats;
136
137 /*
138 * Reading the space map root can fail, so we read it into this
139 * buffer before the superblock is locked and updated.
140 */
141 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
142
143 /*
144 * Set if a transaction has to be aborted but the attempt to roll
145 * back to the previous (good) transaction failed. The only
146 * metadata operation permissible in this state is the closing of
147 * the device.
148 */
149 bool fail_io:1;
150
151 /*
152 * Metadata format 2 fields.
153 */
154 dm_block_t dirty_root;
155 struct dm_disk_bitset dirty_info;
156
157 /*
158 * These structures are used when loading metadata. They're too
159 * big to put on the stack.
160 */
161 struct dm_array_cursor mapping_cursor;
162 struct dm_array_cursor hint_cursor;
163 struct dm_bitset_cursor dirty_cursor;
164 };
165
166 /*-------------------------------------------------------------------
167 * superblock validator
168 *-----------------------------------------------------------------*/
169
170 #define SUPERBLOCK_CSUM_XOR 9031977
171
172 static void sb_prepare_for_write(struct dm_block_validator *v,
173 struct dm_block *b,
174 size_t sb_block_size)
175 {
176 struct cache_disk_superblock *disk_super = dm_block_data(b);
177
178 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
179 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
180 sb_block_size - sizeof(__le32),
181 SUPERBLOCK_CSUM_XOR));
182 }
183
184 static int check_metadata_version(struct cache_disk_superblock *disk_super)
185 {
186 uint32_t metadata_version = le32_to_cpu(disk_super->version);
187
188 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
189 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
190 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
191 return -EINVAL;
192 }
193
194 return 0;
195 }
196
197 static int sb_check(struct dm_block_validator *v,
198 struct dm_block *b,
199 size_t sb_block_size)
200 {
201 struct cache_disk_superblock *disk_super = dm_block_data(b);
202 __le32 csum_le;
203
204 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
205 DMERR("sb_check failed: blocknr %llu: wanted %llu",
206 le64_to_cpu(disk_super->blocknr),
207 (unsigned long long)dm_block_location(b));
208 return -ENOTBLK;
209 }
210
211 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
212 DMERR("sb_check failed: magic %llu: wanted %llu",
213 le64_to_cpu(disk_super->magic),
214 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
215 return -EILSEQ;
216 }
217
218 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
219 sb_block_size - sizeof(__le32),
220 SUPERBLOCK_CSUM_XOR));
221 if (csum_le != disk_super->csum) {
222 DMERR("sb_check failed: csum %u: wanted %u",
223 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
224 return -EILSEQ;
225 }
226
227 return check_metadata_version(disk_super);
228 }
229
230 static struct dm_block_validator sb_validator = {
231 .name = "superblock",
232 .prepare_for_write = sb_prepare_for_write,
233 .check = sb_check
234 };
235
236 /*----------------------------------------------------------------*/
237
238 static int superblock_read_lock(struct dm_cache_metadata *cmd,
239 struct dm_block **sblock)
240 {
241 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
242 &sb_validator, sblock);
243 }
244
245 static int superblock_lock_zero(struct dm_cache_metadata *cmd,
246 struct dm_block **sblock)
247 {
248 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
249 &sb_validator, sblock);
250 }
251
252 static int superblock_lock(struct dm_cache_metadata *cmd,
253 struct dm_block **sblock)
254 {
255 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
256 &sb_validator, sblock);
257 }
258
259 /*----------------------------------------------------------------*/
260
261 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
262 {
263 int r;
264 unsigned i;
265 struct dm_block *b;
266 __le64 *data_le, zero = cpu_to_le64(0);
267 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
268
269 /*
270 * We can't use a validator here - it may be all zeroes.
271 */
272 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
273 if (r)
274 return r;
275
276 data_le = dm_block_data(b);
277 *result = true;
278 for (i = 0; i < sb_block_size; i++) {
279 if (data_le[i] != zero) {
280 *result = false;
281 break;
282 }
283 }
284
285 dm_bm_unlock(b);
286
287 return 0;
288 }
289
290 static void __setup_mapping_info(struct dm_cache_metadata *cmd)
291 {
292 struct dm_btree_value_type vt;
293
294 vt.context = NULL;
295 vt.size = sizeof(__le64);
296 vt.inc = NULL;
297 vt.dec = NULL;
298 vt.equal = NULL;
299 dm_array_info_init(&cmd->info, cmd->tm, &vt);
300
301 if (cmd->policy_hint_size) {
302 vt.size = sizeof(__le32);
303 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
304 }
305 }
306
307 static int __save_sm_root(struct dm_cache_metadata *cmd)
308 {
309 int r;
310 size_t metadata_len;
311
312 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
313 if (r < 0)
314 return r;
315
316 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
317 metadata_len);
318 }
319
320 static void __copy_sm_root(struct dm_cache_metadata *cmd,
321 struct cache_disk_superblock *disk_super)
322 {
323 memcpy(&disk_super->metadata_space_map_root,
324 &cmd->metadata_space_map_root,
325 sizeof(cmd->metadata_space_map_root));
326 }
327
328 static bool separate_dirty_bits(struct dm_cache_metadata *cmd)
329 {
330 return cmd->version >= 2;
331 }
332
333 static int __write_initial_superblock(struct dm_cache_metadata *cmd)
334 {
335 int r;
336 struct dm_block *sblock;
337 struct cache_disk_superblock *disk_super;
338 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
339
340 /* FIXME: see if we can lose the max sectors limit */
341 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
342 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
343
344 r = dm_tm_pre_commit(cmd->tm);
345 if (r < 0)
346 return r;
347
348 /*
349 * dm_sm_copy_root() can fail. So we need to do it before we start
350 * updating the superblock.
351 */
352 r = __save_sm_root(cmd);
353 if (r)
354 return r;
355
356 r = superblock_lock_zero(cmd, &sblock);
357 if (r)
358 return r;
359
360 disk_super = dm_block_data(sblock);
361 disk_super->flags = 0;
362 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
363 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
364 disk_super->version = cpu_to_le32(cmd->version);
365 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
366 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
367 disk_super->policy_hint_size = 0;
368
369 __copy_sm_root(cmd, disk_super);
370
371 disk_super->mapping_root = cpu_to_le64(cmd->root);
372 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
373 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
374 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
375 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
376 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
377 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
378 disk_super->cache_blocks = cpu_to_le32(0);
379
380 disk_super->read_hits = cpu_to_le32(0);
381 disk_super->read_misses = cpu_to_le32(0);
382 disk_super->write_hits = cpu_to_le32(0);
383 disk_super->write_misses = cpu_to_le32(0);
384
385 if (separate_dirty_bits(cmd))
386 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
387
388 return dm_tm_commit(cmd->tm, sblock);
389 }
390
391 static int __format_metadata(struct dm_cache_metadata *cmd)
392 {
393 int r;
394
395 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
396 &cmd->tm, &cmd->metadata_sm);
397 if (r < 0) {
398 DMERR("tm_create_with_sm failed");
399 return r;
400 }
401
402 __setup_mapping_info(cmd);
403
404 r = dm_array_empty(&cmd->info, &cmd->root);
405 if (r < 0)
406 goto bad;
407
408 if (separate_dirty_bits(cmd)) {
409 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
410 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root);
411 if (r < 0)
412 goto bad;
413 }
414
415 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
416 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
417 if (r < 0)
418 goto bad;
419
420 cmd->discard_block_size = 0;
421 cmd->discard_nr_blocks = 0;
422
423 r = __write_initial_superblock(cmd);
424 if (r)
425 goto bad;
426
427 cmd->clean_when_opened = true;
428 return 0;
429
430 bad:
431 dm_tm_destroy(cmd->tm);
432 dm_sm_destroy(cmd->metadata_sm);
433
434 return r;
435 }
436
437 static int __check_incompat_features(struct cache_disk_superblock *disk_super,
438 struct dm_cache_metadata *cmd)
439 {
440 uint32_t incompat_flags, features;
441
442 incompat_flags = le32_to_cpu(disk_super->incompat_flags);
443 features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
444 if (features) {
445 DMERR("could not access metadata due to unsupported optional features (%lx).",
446 (unsigned long)features);
447 return -EINVAL;
448 }
449
450 /*
451 * Check for read-only metadata to skip the following RDWR checks.
452 */
453 if (get_disk_ro(cmd->bdev->bd_disk))
454 return 0;
455
456 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
457 if (features) {
458 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
459 (unsigned long)features);
460 return -EINVAL;
461 }
462
463 return 0;
464 }
465
466 static int __open_metadata(struct dm_cache_metadata *cmd)
467 {
468 int r;
469 struct dm_block *sblock;
470 struct cache_disk_superblock *disk_super;
471 unsigned long sb_flags;
472
473 r = superblock_read_lock(cmd, &sblock);
474 if (r < 0) {
475 DMERR("couldn't read lock superblock");
476 return r;
477 }
478
479 disk_super = dm_block_data(sblock);
480
481 /* Verify the data block size hasn't changed */
482 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
483 DMERR("changing the data block size (from %u to %llu) is not supported",
484 le32_to_cpu(disk_super->data_block_size),
485 (unsigned long long)cmd->data_block_size);
486 r = -EINVAL;
487 goto bad;
488 }
489
490 r = __check_incompat_features(disk_super, cmd);
491 if (r < 0)
492 goto bad;
493
494 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
495 disk_super->metadata_space_map_root,
496 sizeof(disk_super->metadata_space_map_root),
497 &cmd->tm, &cmd->metadata_sm);
498 if (r < 0) {
499 DMERR("tm_open_with_sm failed");
500 goto bad;
501 }
502
503 __setup_mapping_info(cmd);
504 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
505 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
506 sb_flags = le32_to_cpu(disk_super->flags);
507 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
508 dm_bm_unlock(sblock);
509
510 return 0;
511
512 bad:
513 dm_bm_unlock(sblock);
514 return r;
515 }
516
517 static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
518 bool format_device)
519 {
520 int r;
521 bool unformatted = false;
522
523 r = __superblock_all_zeroes(cmd->bm, &unformatted);
524 if (r)
525 return r;
526
527 if (unformatted)
528 return format_device ? __format_metadata(cmd) : -EPERM;
529
530 return __open_metadata(cmd);
531 }
532
533 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
534 bool may_format_device)
535 {
536 int r;
537 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
538 CACHE_METADATA_CACHE_SIZE,
539 CACHE_MAX_CONCURRENT_LOCKS);
540 if (IS_ERR(cmd->bm)) {
541 DMERR("could not create block manager");
542 return PTR_ERR(cmd->bm);
543 }
544
545 r = __open_or_format_metadata(cmd, may_format_device);
546 if (r)
547 dm_block_manager_destroy(cmd->bm);
548
549 return r;
550 }
551
552 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
553 {
554 dm_sm_destroy(cmd->metadata_sm);
555 dm_tm_destroy(cmd->tm);
556 dm_block_manager_destroy(cmd->bm);
557 }
558
559 typedef unsigned long (*flags_mutator)(unsigned long);
560
561 static void update_flags(struct cache_disk_superblock *disk_super,
562 flags_mutator mutator)
563 {
564 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
565 disk_super->flags = cpu_to_le32(sb_flags);
566 }
567
568 static unsigned long set_clean_shutdown(unsigned long flags)
569 {
570 set_bit(CLEAN_SHUTDOWN, &flags);
571 return flags;
572 }
573
574 static unsigned long clear_clean_shutdown(unsigned long flags)
575 {
576 clear_bit(CLEAN_SHUTDOWN, &flags);
577 return flags;
578 }
579
580 static void read_superblock_fields(struct dm_cache_metadata *cmd,
581 struct cache_disk_superblock *disk_super)
582 {
583 cmd->version = le32_to_cpu(disk_super->version);
584 cmd->flags = le32_to_cpu(disk_super->flags);
585 cmd->root = le64_to_cpu(disk_super->mapping_root);
586 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
587 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
588 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
589 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
590 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
591 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
592 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
593 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
594 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
595 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
596 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
597
598 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
599 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
600 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
601 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
602
603 if (separate_dirty_bits(cmd))
604 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
605
606 cmd->changed = false;
607 }
608
609 /*
610 * The mutator updates the superblock flags.
611 */
612 static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
613 flags_mutator mutator)
614 {
615 int r;
616 struct cache_disk_superblock *disk_super;
617 struct dm_block *sblock;
618
619 r = superblock_lock(cmd, &sblock);
620 if (r)
621 return r;
622
623 disk_super = dm_block_data(sblock);
624 update_flags(disk_super, mutator);
625 read_superblock_fields(cmd, disk_super);
626 dm_bm_unlock(sblock);
627
628 return dm_bm_flush(cmd->bm);
629 }
630
631 static int __begin_transaction(struct dm_cache_metadata *cmd)
632 {
633 int r;
634 struct cache_disk_superblock *disk_super;
635 struct dm_block *sblock;
636
637 /*
638 * We re-read the superblock every time. Shouldn't need to do this
639 * really.
640 */
641 r = superblock_read_lock(cmd, &sblock);
642 if (r)
643 return r;
644
645 disk_super = dm_block_data(sblock);
646 read_superblock_fields(cmd, disk_super);
647 dm_bm_unlock(sblock);
648
649 return 0;
650 }
651
652 static int __commit_transaction(struct dm_cache_metadata *cmd,
653 flags_mutator mutator)
654 {
655 int r;
656 struct cache_disk_superblock *disk_super;
657 struct dm_block *sblock;
658
659 /*
660 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
661 */
662 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
663
664 if (separate_dirty_bits(cmd)) {
665 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
666 &cmd->dirty_root);
667 if (r)
668 return r;
669 }
670
671 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
672 &cmd->discard_root);
673 if (r)
674 return r;
675
676 r = dm_tm_pre_commit(cmd->tm);
677 if (r < 0)
678 return r;
679
680 r = __save_sm_root(cmd);
681 if (r)
682 return r;
683
684 r = superblock_lock(cmd, &sblock);
685 if (r)
686 return r;
687
688 disk_super = dm_block_data(sblock);
689
690 disk_super->flags = cpu_to_le32(cmd->flags);
691 if (mutator)
692 update_flags(disk_super, mutator);
693
694 disk_super->mapping_root = cpu_to_le64(cmd->root);
695 if (separate_dirty_bits(cmd))
696 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
697 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
698 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
699 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
700 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
701 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
702 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
703 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
704 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
705 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
706
707 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
708 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
709 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
710 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
711 __copy_sm_root(cmd, disk_super);
712
713 return dm_tm_commit(cmd->tm, sblock);
714 }
715
716 /*----------------------------------------------------------------*/
717
718 /*
719 * The mappings are held in a dm-array that has 64-bit values stored in
720 * little-endian format. The index is the cblock, the high 48bits of the
721 * value are the oblock and the low 16 bit the flags.
722 */
723 #define FLAGS_MASK ((1 << 16) - 1)
724
725 static __le64 pack_value(dm_oblock_t block, unsigned flags)
726 {
727 uint64_t value = from_oblock(block);
728 value <<= 16;
729 value = value | (flags & FLAGS_MASK);
730 return cpu_to_le64(value);
731 }
732
733 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
734 {
735 uint64_t value = le64_to_cpu(value_le);
736 uint64_t b = value >> 16;
737 *block = to_oblock(b);
738 *flags = value & FLAGS_MASK;
739 }
740
741 /*----------------------------------------------------------------*/
742
743 static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
744 sector_t data_block_size,
745 bool may_format_device,
746 size_t policy_hint_size,
747 unsigned metadata_version)
748 {
749 int r;
750 struct dm_cache_metadata *cmd;
751
752 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
753 if (!cmd) {
754 DMERR("could not allocate metadata struct");
755 return ERR_PTR(-ENOMEM);
756 }
757
758 cmd->version = metadata_version;
759 atomic_set(&cmd->ref_count, 1);
760 init_rwsem(&cmd->root_lock);
761 cmd->bdev = bdev;
762 cmd->data_block_size = data_block_size;
763 cmd->cache_blocks = 0;
764 cmd->policy_hint_size = policy_hint_size;
765 cmd->changed = true;
766 cmd->fail_io = false;
767
768 r = __create_persistent_data_objects(cmd, may_format_device);
769 if (r) {
770 kfree(cmd);
771 return ERR_PTR(r);
772 }
773
774 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
775 if (r < 0) {
776 dm_cache_metadata_close(cmd);
777 return ERR_PTR(r);
778 }
779
780 return cmd;
781 }
782
783 /*
784 * We keep a little list of ref counted metadata objects to prevent two
785 * different target instances creating separate bufio instances. This is
786 * an issue if a table is reloaded before the suspend.
787 */
788 static DEFINE_MUTEX(table_lock);
789 static LIST_HEAD(table);
790
791 static struct dm_cache_metadata *lookup(struct block_device *bdev)
792 {
793 struct dm_cache_metadata *cmd;
794
795 list_for_each_entry(cmd, &table, list)
796 if (cmd->bdev == bdev) {
797 atomic_inc(&cmd->ref_count);
798 return cmd;
799 }
800
801 return NULL;
802 }
803
804 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
805 sector_t data_block_size,
806 bool may_format_device,
807 size_t policy_hint_size,
808 unsigned metadata_version)
809 {
810 struct dm_cache_metadata *cmd, *cmd2;
811
812 mutex_lock(&table_lock);
813 cmd = lookup(bdev);
814 mutex_unlock(&table_lock);
815
816 if (cmd)
817 return cmd;
818
819 cmd = metadata_open(bdev, data_block_size, may_format_device,
820 policy_hint_size, metadata_version);
821 if (!IS_ERR(cmd)) {
822 mutex_lock(&table_lock);
823 cmd2 = lookup(bdev);
824 if (cmd2) {
825 mutex_unlock(&table_lock);
826 __destroy_persistent_data_objects(cmd);
827 kfree(cmd);
828 return cmd2;
829 }
830 list_add(&cmd->list, &table);
831 mutex_unlock(&table_lock);
832 }
833
834 return cmd;
835 }
836
837 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
838 {
839 if (cmd->data_block_size != data_block_size) {
840 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
841 (unsigned long long) data_block_size,
842 (unsigned long long) cmd->data_block_size);
843 return false;
844 }
845
846 return true;
847 }
848
849 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
850 sector_t data_block_size,
851 bool may_format_device,
852 size_t policy_hint_size,
853 unsigned metadata_version)
854 {
855 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
856 policy_hint_size, metadata_version);
857
858 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
859 dm_cache_metadata_close(cmd);
860 return ERR_PTR(-EINVAL);
861 }
862
863 return cmd;
864 }
865
866 void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
867 {
868 if (atomic_dec_and_test(&cmd->ref_count)) {
869 mutex_lock(&table_lock);
870 list_del(&cmd->list);
871 mutex_unlock(&table_lock);
872
873 if (!cmd->fail_io)
874 __destroy_persistent_data_objects(cmd);
875 kfree(cmd);
876 }
877 }
878
879 /*
880 * Checks that the given cache block is either unmapped or clean.
881 */
882 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
883 bool *result)
884 {
885 int r;
886 __le64 value;
887 dm_oblock_t ob;
888 unsigned flags;
889
890 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
891 if (r)
892 return r;
893
894 unpack_value(value, &ob, &flags);
895 *result = !((flags & M_VALID) && (flags & M_DIRTY));
896
897 return 0;
898 }
899
900 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
901 dm_cblock_t begin, dm_cblock_t end,
902 bool *result)
903 {
904 int r;
905 *result = true;
906
907 while (begin != end) {
908 r = block_clean_combined_dirty(cmd, begin, result);
909 if (r) {
910 DMERR("block_clean_combined_dirty failed");
911 return r;
912 }
913
914 if (!*result) {
915 DMERR("cache block %llu is dirty",
916 (unsigned long long) from_cblock(begin));
917 return 0;
918 }
919
920 begin = to_cblock(from_cblock(begin) + 1);
921 }
922
923 return 0;
924 }
925
926 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
927 dm_cblock_t begin, dm_cblock_t end,
928 bool *result)
929 {
930 int r;
931 bool dirty_flag;
932 *result = true;
933
934 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
935 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
936 if (r) {
937 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__);
938 return r;
939 }
940
941 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin));
942 if (r) {
943 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
944 dm_bitset_cursor_end(&cmd->dirty_cursor);
945 return r;
946 }
947
948 while (begin != end) {
949 /*
950 * We assume that unmapped blocks have their dirty bit
951 * cleared.
952 */
953 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor);
954 if (dirty_flag) {
955 DMERR("%s: cache block %llu is dirty", __func__,
956 (unsigned long long) from_cblock(begin));
957 dm_bitset_cursor_end(&cmd->dirty_cursor);
958 *result = false;
959 return 0;
960 }
961
962 begin = to_cblock(from_cblock(begin) + 1);
963 if (begin == end)
964 break;
965
966 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
967 if (r) {
968 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
969 dm_bitset_cursor_end(&cmd->dirty_cursor);
970 return r;
971 }
972 }
973
974 dm_bitset_cursor_end(&cmd->dirty_cursor);
975
976 return 0;
977 }
978
979 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
980 dm_cblock_t begin, dm_cblock_t end,
981 bool *result)
982 {
983 if (separate_dirty_bits(cmd))
984 return blocks_are_clean_separate_dirty(cmd, begin, end, result);
985 else
986 return blocks_are_clean_combined_dirty(cmd, begin, end, result);
987 }
988
989 static bool cmd_write_lock(struct dm_cache_metadata *cmd)
990 {
991 down_write(&cmd->root_lock);
992 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
993 up_write(&cmd->root_lock);
994 return false;
995 }
996 return true;
997 }
998
999 #define WRITE_LOCK(cmd) \
1000 do { \
1001 if (!cmd_write_lock((cmd))) \
1002 return -EINVAL; \
1003 } while(0)
1004
1005 #define WRITE_LOCK_VOID(cmd) \
1006 do { \
1007 if (!cmd_write_lock((cmd))) \
1008 return; \
1009 } while(0)
1010
1011 #define WRITE_UNLOCK(cmd) \
1012 up_write(&(cmd)->root_lock)
1013
1014 static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1015 {
1016 down_read(&cmd->root_lock);
1017 if (cmd->fail_io) {
1018 up_read(&cmd->root_lock);
1019 return false;
1020 }
1021 return true;
1022 }
1023
1024 #define READ_LOCK(cmd) \
1025 do { \
1026 if (!cmd_read_lock((cmd))) \
1027 return -EINVAL; \
1028 } while(0)
1029
1030 #define READ_LOCK_VOID(cmd) \
1031 do { \
1032 if (!cmd_read_lock((cmd))) \
1033 return; \
1034 } while(0)
1035
1036 #define READ_UNLOCK(cmd) \
1037 up_read(&(cmd)->root_lock)
1038
1039 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1040 {
1041 int r;
1042 bool clean;
1043 __le64 null_mapping = pack_value(0, 0);
1044
1045 WRITE_LOCK(cmd);
1046 __dm_bless_for_disk(&null_mapping);
1047
1048 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1049 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
1050 if (r) {
1051 __dm_unbless_for_disk(&null_mapping);
1052 goto out;
1053 }
1054
1055 if (!clean) {
1056 DMERR("unable to shrink cache due to dirty blocks");
1057 r = -EINVAL;
1058 __dm_unbless_for_disk(&null_mapping);
1059 goto out;
1060 }
1061 }
1062
1063 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1064 from_cblock(new_cache_size),
1065 &null_mapping, &cmd->root);
1066 if (r)
1067 goto out;
1068
1069 if (separate_dirty_bits(cmd)) {
1070 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1071 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1072 false, &cmd->dirty_root);
1073 if (r)
1074 goto out;
1075 }
1076
1077 cmd->cache_blocks = new_cache_size;
1078 cmd->changed = true;
1079
1080 out:
1081 WRITE_UNLOCK(cmd);
1082
1083 return r;
1084 }
1085
1086 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1087 sector_t discard_block_size,
1088 dm_dblock_t new_nr_entries)
1089 {
1090 int r;
1091
1092 WRITE_LOCK(cmd);
1093 r = dm_bitset_resize(&cmd->discard_info,
1094 cmd->discard_root,
1095 from_dblock(cmd->discard_nr_blocks),
1096 from_dblock(new_nr_entries),
1097 false, &cmd->discard_root);
1098 if (!r) {
1099 cmd->discard_block_size = discard_block_size;
1100 cmd->discard_nr_blocks = new_nr_entries;
1101 }
1102
1103 cmd->changed = true;
1104 WRITE_UNLOCK(cmd);
1105
1106 return r;
1107 }
1108
1109 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1110 {
1111 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
1112 from_dblock(b), &cmd->discard_root);
1113 }
1114
1115 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1116 {
1117 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
1118 from_dblock(b), &cmd->discard_root);
1119 }
1120
1121 static int __discard(struct dm_cache_metadata *cmd,
1122 dm_dblock_t dblock, bool discard)
1123 {
1124 int r;
1125
1126 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1127 if (r)
1128 return r;
1129
1130 cmd->changed = true;
1131 return 0;
1132 }
1133
1134 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1135 dm_dblock_t dblock, bool discard)
1136 {
1137 int r;
1138
1139 WRITE_LOCK(cmd);
1140 r = __discard(cmd, dblock, discard);
1141 WRITE_UNLOCK(cmd);
1142
1143 return r;
1144 }
1145
1146 static int __load_discards(struct dm_cache_metadata *cmd,
1147 load_discard_fn fn, void *context)
1148 {
1149 int r = 0;
1150 uint32_t b;
1151 struct dm_bitset_cursor c;
1152
1153 if (from_dblock(cmd->discard_nr_blocks) == 0)
1154 /* nothing to do */
1155 return 0;
1156
1157 if (cmd->clean_when_opened) {
1158 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1159 if (r)
1160 return r;
1161
1162 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1163 from_dblock(cmd->discard_nr_blocks), &c);
1164 if (r)
1165 return r;
1166
1167 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1168 r = fn(context, cmd->discard_block_size, to_dblock(b),
1169 dm_bitset_cursor_get_value(&c));
1170 if (r)
1171 break;
1172 }
1173
1174 dm_bitset_cursor_end(&c);
1175
1176 } else {
1177 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1178 r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1179 if (r)
1180 return r;
1181 }
1182 }
1183
1184 return r;
1185 }
1186
1187 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1188 load_discard_fn fn, void *context)
1189 {
1190 int r;
1191
1192 READ_LOCK(cmd);
1193 r = __load_discards(cmd, fn, context);
1194 READ_UNLOCK(cmd);
1195
1196 return r;
1197 }
1198
1199 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1200 {
1201 READ_LOCK(cmd);
1202 *result = cmd->cache_blocks;
1203 READ_UNLOCK(cmd);
1204
1205 return 0;
1206 }
1207
1208 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1209 {
1210 int r;
1211 __le64 value = pack_value(0, 0);
1212
1213 __dm_bless_for_disk(&value);
1214 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1215 &value, &cmd->root);
1216 if (r)
1217 return r;
1218
1219 cmd->changed = true;
1220 return 0;
1221 }
1222
1223 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1224 {
1225 int r;
1226
1227 WRITE_LOCK(cmd);
1228 r = __remove(cmd, cblock);
1229 WRITE_UNLOCK(cmd);
1230
1231 return r;
1232 }
1233
1234 static int __insert(struct dm_cache_metadata *cmd,
1235 dm_cblock_t cblock, dm_oblock_t oblock)
1236 {
1237 int r;
1238 __le64 value = pack_value(oblock, M_VALID);
1239 __dm_bless_for_disk(&value);
1240
1241 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1242 &value, &cmd->root);
1243 if (r)
1244 return r;
1245
1246 cmd->changed = true;
1247 return 0;
1248 }
1249
1250 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1251 dm_cblock_t cblock, dm_oblock_t oblock)
1252 {
1253 int r;
1254
1255 WRITE_LOCK(cmd);
1256 r = __insert(cmd, cblock, oblock);
1257 WRITE_UNLOCK(cmd);
1258
1259 return r;
1260 }
1261
1262 struct thunk {
1263 load_mapping_fn fn;
1264 void *context;
1265
1266 struct dm_cache_metadata *cmd;
1267 bool respect_dirty_flags;
1268 bool hints_valid;
1269 };
1270
1271 static bool policy_unchanged(struct dm_cache_metadata *cmd,
1272 struct dm_cache_policy *policy)
1273 {
1274 const char *policy_name = dm_cache_policy_get_name(policy);
1275 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1276 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1277
1278 /*
1279 * Ensure policy names match.
1280 */
1281 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1282 return false;
1283
1284 /*
1285 * Ensure policy major versions match.
1286 */
1287 if (cmd->policy_version[0] != policy_version[0])
1288 return false;
1289
1290 /*
1291 * Ensure policy hint sizes match.
1292 */
1293 if (cmd->policy_hint_size != policy_hint_size)
1294 return false;
1295
1296 return true;
1297 }
1298
1299 static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1300 {
1301 return cmd->hint_root && cmd->policy_hint_size;
1302 }
1303
1304 static bool hints_array_available(struct dm_cache_metadata *cmd,
1305 struct dm_cache_policy *policy)
1306 {
1307 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1308 hints_array_initialized(cmd);
1309 }
1310
1311 static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1312 uint64_t cb, bool hints_valid,
1313 struct dm_array_cursor *mapping_cursor,
1314 struct dm_array_cursor *hint_cursor,
1315 load_mapping_fn fn, void *context)
1316 {
1317 int r = 0;
1318
1319 __le64 mapping;
1320 __le32 hint = 0;
1321
1322 __le64 *mapping_value_le;
1323 __le32 *hint_value_le;
1324
1325 dm_oblock_t oblock;
1326 unsigned flags;
1327
1328 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1329 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1330 unpack_value(mapping, &oblock, &flags);
1331
1332 if (flags & M_VALID) {
1333 if (hints_valid) {
1334 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1335 memcpy(&hint, hint_value_le, sizeof(hint));
1336 }
1337
1338 r = fn(context, oblock, to_cblock(cb), flags & M_DIRTY,
1339 le32_to_cpu(hint), hints_valid);
1340 if (r) {
1341 DMERR("policy couldn't load cache block %llu",
1342 (unsigned long long) from_cblock(to_cblock(cb)));
1343 }
1344 }
1345
1346 return r;
1347 }
1348
1349 static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1350 uint64_t cb, bool hints_valid,
1351 struct dm_array_cursor *mapping_cursor,
1352 struct dm_array_cursor *hint_cursor,
1353 struct dm_bitset_cursor *dirty_cursor,
1354 load_mapping_fn fn, void *context)
1355 {
1356 int r = 0;
1357
1358 __le64 mapping;
1359 __le32 hint = 0;
1360
1361 __le64 *mapping_value_le;
1362 __le32 *hint_value_le;
1363
1364 dm_oblock_t oblock;
1365 unsigned flags;
1366 bool dirty;
1367
1368 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1369 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1370 unpack_value(mapping, &oblock, &flags);
1371
1372 if (flags & M_VALID) {
1373 if (hints_valid) {
1374 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1375 memcpy(&hint, hint_value_le, sizeof(hint));
1376 }
1377
1378 dirty = dm_bitset_cursor_get_value(dirty_cursor);
1379 r = fn(context, oblock, to_cblock(cb), dirty,
1380 le32_to_cpu(hint), hints_valid);
1381 if (r) {
1382 DMERR("policy couldn't load cache block %llu",
1383 (unsigned long long) from_cblock(to_cblock(cb)));
1384 }
1385 }
1386
1387 return r;
1388 }
1389
1390 static int __load_mappings(struct dm_cache_metadata *cmd,
1391 struct dm_cache_policy *policy,
1392 load_mapping_fn fn, void *context)
1393 {
1394 int r;
1395 uint64_t cb;
1396
1397 bool hints_valid = hints_array_available(cmd, policy);
1398
1399 if (from_cblock(cmd->cache_blocks) == 0)
1400 /* Nothing to do */
1401 return 0;
1402
1403 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1404 if (r)
1405 return r;
1406
1407 if (hints_valid) {
1408 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1409 if (r) {
1410 dm_array_cursor_end(&cmd->mapping_cursor);
1411 return r;
1412 }
1413 }
1414
1415 if (separate_dirty_bits(cmd)) {
1416 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1417 from_cblock(cmd->cache_blocks),
1418 &cmd->dirty_cursor);
1419 if (r) {
1420 dm_array_cursor_end(&cmd->hint_cursor);
1421 dm_array_cursor_end(&cmd->mapping_cursor);
1422 return r;
1423 }
1424 }
1425
1426 for (cb = 0; ; cb++) {
1427 if (separate_dirty_bits(cmd))
1428 r = __load_mapping_v2(cmd, cb, hints_valid,
1429 &cmd->mapping_cursor,
1430 &cmd->hint_cursor,
1431 &cmd->dirty_cursor,
1432 fn, context);
1433 else
1434 r = __load_mapping_v1(cmd, cb, hints_valid,
1435 &cmd->mapping_cursor, &cmd->hint_cursor,
1436 fn, context);
1437 if (r)
1438 goto out;
1439
1440 /*
1441 * We need to break out before we move the cursors.
1442 */
1443 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1444 break;
1445
1446 r = dm_array_cursor_next(&cmd->mapping_cursor);
1447 if (r) {
1448 DMERR("dm_array_cursor_next for mapping failed");
1449 goto out;
1450 }
1451
1452 if (hints_valid) {
1453 r = dm_array_cursor_next(&cmd->hint_cursor);
1454 if (r) {
1455 DMERR("dm_array_cursor_next for hint failed");
1456 goto out;
1457 }
1458 }
1459
1460 if (separate_dirty_bits(cmd)) {
1461 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1462 if (r) {
1463 DMERR("dm_bitset_cursor_next for dirty failed");
1464 goto out;
1465 }
1466 }
1467 }
1468 out:
1469 dm_array_cursor_end(&cmd->mapping_cursor);
1470 if (hints_valid)
1471 dm_array_cursor_end(&cmd->hint_cursor);
1472
1473 if (separate_dirty_bits(cmd))
1474 dm_bitset_cursor_end(&cmd->dirty_cursor);
1475
1476 return r;
1477 }
1478
1479 int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1480 struct dm_cache_policy *policy,
1481 load_mapping_fn fn, void *context)
1482 {
1483 int r;
1484
1485 READ_LOCK(cmd);
1486 r = __load_mappings(cmd, policy, fn, context);
1487 READ_UNLOCK(cmd);
1488
1489 return r;
1490 }
1491
1492 static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1493 {
1494 int r = 0;
1495 __le64 value;
1496 dm_oblock_t oblock;
1497 unsigned flags;
1498
1499 memcpy(&value, leaf, sizeof(value));
1500 unpack_value(value, &oblock, &flags);
1501
1502 return r;
1503 }
1504
1505 static int __dump_mappings(struct dm_cache_metadata *cmd)
1506 {
1507 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1508 }
1509
1510 void dm_cache_dump(struct dm_cache_metadata *cmd)
1511 {
1512 READ_LOCK_VOID(cmd);
1513 __dump_mappings(cmd);
1514 READ_UNLOCK(cmd);
1515 }
1516
1517 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1518 {
1519 int r;
1520
1521 READ_LOCK(cmd);
1522 r = cmd->changed;
1523 READ_UNLOCK(cmd);
1524
1525 return r;
1526 }
1527
1528 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1529 {
1530 int r;
1531 unsigned flags;
1532 dm_oblock_t oblock;
1533 __le64 value;
1534
1535 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1536 if (r)
1537 return r;
1538
1539 unpack_value(value, &oblock, &flags);
1540
1541 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1542 /* nothing to be done */
1543 return 0;
1544
1545 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1546 __dm_bless_for_disk(&value);
1547
1548 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1549 &value, &cmd->root);
1550 if (r)
1551 return r;
1552
1553 cmd->changed = true;
1554 return 0;
1555
1556 }
1557
1558 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1559 {
1560 int r;
1561 unsigned i;
1562 for (i = 0; i < nr_bits; i++) {
1563 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1564 if (r)
1565 return r;
1566 }
1567
1568 return 0;
1569 }
1570
1571 static int is_dirty_callback(uint32_t index, bool *value, void *context)
1572 {
1573 unsigned long *bits = context;
1574 *value = test_bit(index, bits);
1575 return 0;
1576 }
1577
1578 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1579 {
1580 int r = 0;
1581
1582 /* nr_bits is really just a sanity check */
1583 if (nr_bits != from_cblock(cmd->cache_blocks)) {
1584 DMERR("dirty bitset is wrong size");
1585 return -EINVAL;
1586 }
1587
1588 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1589 if (r)
1590 return r;
1591
1592 cmd->changed = true;
1593 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1594 }
1595
1596 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1597 unsigned nr_bits,
1598 unsigned long *bits)
1599 {
1600 int r;
1601
1602 WRITE_LOCK(cmd);
1603 if (separate_dirty_bits(cmd))
1604 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1605 else
1606 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1607 WRITE_UNLOCK(cmd);
1608
1609 return r;
1610 }
1611
1612 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1613 struct dm_cache_statistics *stats)
1614 {
1615 READ_LOCK_VOID(cmd);
1616 *stats = cmd->stats;
1617 READ_UNLOCK(cmd);
1618 }
1619
1620 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1621 struct dm_cache_statistics *stats)
1622 {
1623 WRITE_LOCK_VOID(cmd);
1624 cmd->stats = *stats;
1625 WRITE_UNLOCK(cmd);
1626 }
1627
1628 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1629 {
1630 int r;
1631 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1632 clear_clean_shutdown);
1633
1634 WRITE_LOCK(cmd);
1635 r = __commit_transaction(cmd, mutator);
1636 if (r)
1637 goto out;
1638
1639 r = __begin_transaction(cmd);
1640
1641 out:
1642 WRITE_UNLOCK(cmd);
1643 return r;
1644 }
1645
1646 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1647 dm_block_t *result)
1648 {
1649 int r = -EINVAL;
1650
1651 READ_LOCK(cmd);
1652 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1653 READ_UNLOCK(cmd);
1654
1655 return r;
1656 }
1657
1658 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1659 dm_block_t *result)
1660 {
1661 int r = -EINVAL;
1662
1663 READ_LOCK(cmd);
1664 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1665 READ_UNLOCK(cmd);
1666
1667 return r;
1668 }
1669
1670 /*----------------------------------------------------------------*/
1671
1672 static int get_hint(uint32_t index, void *value_le, void *context)
1673 {
1674 uint32_t value;
1675 struct dm_cache_policy *policy = context;
1676
1677 value = policy_get_hint(policy, to_cblock(index));
1678 *((__le32 *) value_le) = cpu_to_le32(value);
1679
1680 return 0;
1681 }
1682
1683 /*
1684 * It's quicker to always delete the hint array, and recreate with
1685 * dm_array_new().
1686 */
1687 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1688 {
1689 int r;
1690 size_t hint_size;
1691 const char *policy_name = dm_cache_policy_get_name(policy);
1692 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1693
1694 if (!policy_name[0] ||
1695 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1696 return -EINVAL;
1697
1698 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1699 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1700
1701 hint_size = dm_cache_policy_get_hint_size(policy);
1702 if (!hint_size)
1703 return 0; /* short-circuit hints initialization */
1704 cmd->policy_hint_size = hint_size;
1705
1706 if (cmd->hint_root) {
1707 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1708 if (r)
1709 return r;
1710 }
1711
1712 return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1713 from_cblock(cmd->cache_blocks),
1714 get_hint, policy);
1715 }
1716
1717 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1718 {
1719 int r;
1720
1721 WRITE_LOCK(cmd);
1722 r = write_hints(cmd, policy);
1723 WRITE_UNLOCK(cmd);
1724
1725 return r;
1726 }
1727
1728 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1729 {
1730 int r;
1731
1732 READ_LOCK(cmd);
1733 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1734 READ_UNLOCK(cmd);
1735
1736 return r;
1737 }
1738
1739 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1740 {
1741 WRITE_LOCK_VOID(cmd);
1742 dm_bm_set_read_only(cmd->bm);
1743 WRITE_UNLOCK(cmd);
1744 }
1745
1746 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1747 {
1748 WRITE_LOCK_VOID(cmd);
1749 dm_bm_set_read_write(cmd->bm);
1750 WRITE_UNLOCK(cmd);
1751 }
1752
1753 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1754 {
1755 int r;
1756 struct dm_block *sblock;
1757 struct cache_disk_superblock *disk_super;
1758
1759 WRITE_LOCK(cmd);
1760 set_bit(NEEDS_CHECK, &cmd->flags);
1761
1762 r = superblock_lock(cmd, &sblock);
1763 if (r) {
1764 DMERR("couldn't read superblock");
1765 goto out;
1766 }
1767
1768 disk_super = dm_block_data(sblock);
1769 disk_super->flags = cpu_to_le32(cmd->flags);
1770
1771 dm_bm_unlock(sblock);
1772
1773 out:
1774 WRITE_UNLOCK(cmd);
1775 return r;
1776 }
1777
1778 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1779 {
1780 READ_LOCK(cmd);
1781 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1782 READ_UNLOCK(cmd);
1783
1784 return 0;
1785 }
1786
1787 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1788 {
1789 int r;
1790
1791 WRITE_LOCK(cmd);
1792 __destroy_persistent_data_objects(cmd);
1793 r = __create_persistent_data_objects(cmd, false);
1794 if (r)
1795 cmd->fail_io = true;
1796 WRITE_UNLOCK(cmd);
1797
1798 return r;
1799 }
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