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[mirror_ubuntu-bionic-kernel.git] / drivers / md / dm-cache-metadata.c
1 /*
2 * Copyright (C) 2012 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7 #include "dm-cache-metadata.h"
8
9 #include "persistent-data/dm-array.h"
10 #include "persistent-data/dm-bitset.h"
11 #include "persistent-data/dm-space-map.h"
12 #include "persistent-data/dm-space-map-disk.h"
13 #include "persistent-data/dm-transaction-manager.h"
14
15 #include <linux/device-mapper.h>
16 #include <linux/refcount.h>
17
18 /*----------------------------------------------------------------*/
19
20 #define DM_MSG_PREFIX "cache metadata"
21
22 #define CACHE_SUPERBLOCK_MAGIC 06142003
23 #define CACHE_SUPERBLOCK_LOCATION 0
24
25 /*
26 * defines a range of metadata versions that this module can handle.
27 */
28 #define MIN_CACHE_VERSION 1
29 #define MAX_CACHE_VERSION 2
30
31 /*
32 * 3 for btree insert +
33 * 2 for btree lookup used within space map
34 */
35 #define CACHE_MAX_CONCURRENT_LOCKS 5
36 #define SPACE_MAP_ROOT_SIZE 128
37
38 enum superblock_flag_bits {
39 /* for spotting crashes that would invalidate the dirty bitset */
40 CLEAN_SHUTDOWN,
41 /* metadata must be checked using the tools */
42 NEEDS_CHECK,
43 };
44
45 /*
46 * Each mapping from cache block -> origin block carries a set of flags.
47 */
48 enum mapping_bits {
49 /*
50 * A valid mapping. Because we're using an array we clear this
51 * flag for an non existant mapping.
52 */
53 M_VALID = 1,
54
55 /*
56 * The data on the cache is different from that on the origin.
57 * This flag is only used by metadata format 1.
58 */
59 M_DIRTY = 2
60 };
61
62 struct cache_disk_superblock {
63 __le32 csum;
64 __le32 flags;
65 __le64 blocknr;
66
67 __u8 uuid[16];
68 __le64 magic;
69 __le32 version;
70
71 __u8 policy_name[CACHE_POLICY_NAME_SIZE];
72 __le32 policy_hint_size;
73
74 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
75 __le64 mapping_root;
76 __le64 hint_root;
77
78 __le64 discard_root;
79 __le64 discard_block_size;
80 __le64 discard_nr_blocks;
81
82 __le32 data_block_size;
83 __le32 metadata_block_size;
84 __le32 cache_blocks;
85
86 __le32 compat_flags;
87 __le32 compat_ro_flags;
88 __le32 incompat_flags;
89
90 __le32 read_hits;
91 __le32 read_misses;
92 __le32 write_hits;
93 __le32 write_misses;
94
95 __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
96
97 /*
98 * Metadata format 2 fields.
99 */
100 __le64 dirty_root;
101 } __packed;
102
103 struct dm_cache_metadata {
104 refcount_t ref_count;
105 struct list_head list;
106
107 unsigned version;
108 struct block_device *bdev;
109 struct dm_block_manager *bm;
110 struct dm_space_map *metadata_sm;
111 struct dm_transaction_manager *tm;
112
113 struct dm_array_info info;
114 struct dm_array_info hint_info;
115 struct dm_disk_bitset discard_info;
116
117 struct rw_semaphore root_lock;
118 unsigned long flags;
119 dm_block_t root;
120 dm_block_t hint_root;
121 dm_block_t discard_root;
122
123 sector_t discard_block_size;
124 dm_dblock_t discard_nr_blocks;
125
126 sector_t data_block_size;
127 dm_cblock_t cache_blocks;
128 bool changed:1;
129 bool clean_when_opened:1;
130
131 char policy_name[CACHE_POLICY_NAME_SIZE];
132 unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
133 size_t policy_hint_size;
134 struct dm_cache_statistics stats;
135
136 /*
137 * Reading the space map root can fail, so we read it into this
138 * buffer before the superblock is locked and updated.
139 */
140 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
141
142 /*
143 * Set if a transaction has to be aborted but the attempt to roll
144 * back to the previous (good) transaction failed. The only
145 * metadata operation permissible in this state is the closing of
146 * the device.
147 */
148 bool fail_io:1;
149
150 /*
151 * Metadata format 2 fields.
152 */
153 dm_block_t dirty_root;
154 struct dm_disk_bitset dirty_info;
155
156 /*
157 * These structures are used when loading metadata. They're too
158 * big to put on the stack.
159 */
160 struct dm_array_cursor mapping_cursor;
161 struct dm_array_cursor hint_cursor;
162 struct dm_bitset_cursor dirty_cursor;
163 };
164
165 /*-------------------------------------------------------------------
166 * superblock validator
167 *-----------------------------------------------------------------*/
168
169 #define SUPERBLOCK_CSUM_XOR 9031977
170
171 static void sb_prepare_for_write(struct dm_block_validator *v,
172 struct dm_block *b,
173 size_t sb_block_size)
174 {
175 struct cache_disk_superblock *disk_super = dm_block_data(b);
176
177 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
178 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
179 sb_block_size - sizeof(__le32),
180 SUPERBLOCK_CSUM_XOR));
181 }
182
183 static int check_metadata_version(struct cache_disk_superblock *disk_super)
184 {
185 uint32_t metadata_version = le32_to_cpu(disk_super->version);
186
187 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
188 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
189 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
190 return -EINVAL;
191 }
192
193 return 0;
194 }
195
196 static int sb_check(struct dm_block_validator *v,
197 struct dm_block *b,
198 size_t sb_block_size)
199 {
200 struct cache_disk_superblock *disk_super = dm_block_data(b);
201 __le32 csum_le;
202
203 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
204 DMERR("sb_check failed: blocknr %llu: wanted %llu",
205 le64_to_cpu(disk_super->blocknr),
206 (unsigned long long)dm_block_location(b));
207 return -ENOTBLK;
208 }
209
210 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
211 DMERR("sb_check failed: magic %llu: wanted %llu",
212 le64_to_cpu(disk_super->magic),
213 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
214 return -EILSEQ;
215 }
216
217 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
218 sb_block_size - sizeof(__le32),
219 SUPERBLOCK_CSUM_XOR));
220 if (csum_le != disk_super->csum) {
221 DMERR("sb_check failed: csum %u: wanted %u",
222 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
223 return -EILSEQ;
224 }
225
226 return check_metadata_version(disk_super);
227 }
228
229 static struct dm_block_validator sb_validator = {
230 .name = "superblock",
231 .prepare_for_write = sb_prepare_for_write,
232 .check = sb_check
233 };
234
235 /*----------------------------------------------------------------*/
236
237 static int superblock_read_lock(struct dm_cache_metadata *cmd,
238 struct dm_block **sblock)
239 {
240 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
241 &sb_validator, sblock);
242 }
243
244 static int superblock_lock_zero(struct dm_cache_metadata *cmd,
245 struct dm_block **sblock)
246 {
247 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
248 &sb_validator, sblock);
249 }
250
251 static int superblock_lock(struct dm_cache_metadata *cmd,
252 struct dm_block **sblock)
253 {
254 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
255 &sb_validator, sblock);
256 }
257
258 /*----------------------------------------------------------------*/
259
260 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
261 {
262 int r;
263 unsigned i;
264 struct dm_block *b;
265 __le64 *data_le, zero = cpu_to_le64(0);
266 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
267
268 /*
269 * We can't use a validator here - it may be all zeroes.
270 */
271 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
272 if (r)
273 return r;
274
275 data_le = dm_block_data(b);
276 *result = true;
277 for (i = 0; i < sb_block_size; i++) {
278 if (data_le[i] != zero) {
279 *result = false;
280 break;
281 }
282 }
283
284 dm_bm_unlock(b);
285
286 return 0;
287 }
288
289 static void __setup_mapping_info(struct dm_cache_metadata *cmd)
290 {
291 struct dm_btree_value_type vt;
292
293 vt.context = NULL;
294 vt.size = sizeof(__le64);
295 vt.inc = NULL;
296 vt.dec = NULL;
297 vt.equal = NULL;
298 dm_array_info_init(&cmd->info, cmd->tm, &vt);
299
300 if (cmd->policy_hint_size) {
301 vt.size = sizeof(__le32);
302 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
303 }
304 }
305
306 static int __save_sm_root(struct dm_cache_metadata *cmd)
307 {
308 int r;
309 size_t metadata_len;
310
311 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
312 if (r < 0)
313 return r;
314
315 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
316 metadata_len);
317 }
318
319 static void __copy_sm_root(struct dm_cache_metadata *cmd,
320 struct cache_disk_superblock *disk_super)
321 {
322 memcpy(&disk_super->metadata_space_map_root,
323 &cmd->metadata_space_map_root,
324 sizeof(cmd->metadata_space_map_root));
325 }
326
327 static bool separate_dirty_bits(struct dm_cache_metadata *cmd)
328 {
329 return cmd->version >= 2;
330 }
331
332 static int __write_initial_superblock(struct dm_cache_metadata *cmd)
333 {
334 int r;
335 struct dm_block *sblock;
336 struct cache_disk_superblock *disk_super;
337 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
338
339 /* FIXME: see if we can lose the max sectors limit */
340 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
341 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
342
343 r = dm_tm_pre_commit(cmd->tm);
344 if (r < 0)
345 return r;
346
347 /*
348 * dm_sm_copy_root() can fail. So we need to do it before we start
349 * updating the superblock.
350 */
351 r = __save_sm_root(cmd);
352 if (r)
353 return r;
354
355 r = superblock_lock_zero(cmd, &sblock);
356 if (r)
357 return r;
358
359 disk_super = dm_block_data(sblock);
360 disk_super->flags = 0;
361 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
362 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
363 disk_super->version = cpu_to_le32(cmd->version);
364 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
365 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
366 disk_super->policy_hint_size = 0;
367
368 __copy_sm_root(cmd, disk_super);
369
370 disk_super->mapping_root = cpu_to_le64(cmd->root);
371 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
372 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
373 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
374 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
375 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
376 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
377 disk_super->cache_blocks = cpu_to_le32(0);
378
379 disk_super->read_hits = cpu_to_le32(0);
380 disk_super->read_misses = cpu_to_le32(0);
381 disk_super->write_hits = cpu_to_le32(0);
382 disk_super->write_misses = cpu_to_le32(0);
383
384 if (separate_dirty_bits(cmd))
385 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
386
387 return dm_tm_commit(cmd->tm, sblock);
388 }
389
390 static int __format_metadata(struct dm_cache_metadata *cmd)
391 {
392 int r;
393
394 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
395 &cmd->tm, &cmd->metadata_sm);
396 if (r < 0) {
397 DMERR("tm_create_with_sm failed");
398 return r;
399 }
400
401 __setup_mapping_info(cmd);
402
403 r = dm_array_empty(&cmd->info, &cmd->root);
404 if (r < 0)
405 goto bad;
406
407 if (separate_dirty_bits(cmd)) {
408 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
409 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root);
410 if (r < 0)
411 goto bad;
412 }
413
414 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
415 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
416 if (r < 0)
417 goto bad;
418
419 cmd->discard_block_size = 0;
420 cmd->discard_nr_blocks = 0;
421
422 r = __write_initial_superblock(cmd);
423 if (r)
424 goto bad;
425
426 cmd->clean_when_opened = true;
427 return 0;
428
429 bad:
430 dm_tm_destroy(cmd->tm);
431 dm_sm_destroy(cmd->metadata_sm);
432
433 return r;
434 }
435
436 static int __check_incompat_features(struct cache_disk_superblock *disk_super,
437 struct dm_cache_metadata *cmd)
438 {
439 uint32_t incompat_flags, features;
440
441 incompat_flags = le32_to_cpu(disk_super->incompat_flags);
442 features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
443 if (features) {
444 DMERR("could not access metadata due to unsupported optional features (%lx).",
445 (unsigned long)features);
446 return -EINVAL;
447 }
448
449 /*
450 * Check for read-only metadata to skip the following RDWR checks.
451 */
452 if (get_disk_ro(cmd->bdev->bd_disk))
453 return 0;
454
455 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
456 if (features) {
457 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
458 (unsigned long)features);
459 return -EINVAL;
460 }
461
462 return 0;
463 }
464
465 static int __open_metadata(struct dm_cache_metadata *cmd)
466 {
467 int r;
468 struct dm_block *sblock;
469 struct cache_disk_superblock *disk_super;
470 unsigned long sb_flags;
471
472 r = superblock_read_lock(cmd, &sblock);
473 if (r < 0) {
474 DMERR("couldn't read lock superblock");
475 return r;
476 }
477
478 disk_super = dm_block_data(sblock);
479
480 /* Verify the data block size hasn't changed */
481 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
482 DMERR("changing the data block size (from %u to %llu) is not supported",
483 le32_to_cpu(disk_super->data_block_size),
484 (unsigned long long)cmd->data_block_size);
485 r = -EINVAL;
486 goto bad;
487 }
488
489 r = __check_incompat_features(disk_super, cmd);
490 if (r < 0)
491 goto bad;
492
493 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
494 disk_super->metadata_space_map_root,
495 sizeof(disk_super->metadata_space_map_root),
496 &cmd->tm, &cmd->metadata_sm);
497 if (r < 0) {
498 DMERR("tm_open_with_sm failed");
499 goto bad;
500 }
501
502 __setup_mapping_info(cmd);
503 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
504 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
505 sb_flags = le32_to_cpu(disk_super->flags);
506 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
507 dm_bm_unlock(sblock);
508
509 return 0;
510
511 bad:
512 dm_bm_unlock(sblock);
513 return r;
514 }
515
516 static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
517 bool format_device)
518 {
519 int r;
520 bool unformatted = false;
521
522 r = __superblock_all_zeroes(cmd->bm, &unformatted);
523 if (r)
524 return r;
525
526 if (unformatted)
527 return format_device ? __format_metadata(cmd) : -EPERM;
528
529 return __open_metadata(cmd);
530 }
531
532 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
533 bool may_format_device)
534 {
535 int r;
536 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
537 CACHE_MAX_CONCURRENT_LOCKS);
538 if (IS_ERR(cmd->bm)) {
539 DMERR("could not create block manager");
540 return PTR_ERR(cmd->bm);
541 }
542
543 r = __open_or_format_metadata(cmd, may_format_device);
544 if (r)
545 dm_block_manager_destroy(cmd->bm);
546
547 return r;
548 }
549
550 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
551 {
552 dm_sm_destroy(cmd->metadata_sm);
553 dm_tm_destroy(cmd->tm);
554 dm_block_manager_destroy(cmd->bm);
555 }
556
557 typedef unsigned long (*flags_mutator)(unsigned long);
558
559 static void update_flags(struct cache_disk_superblock *disk_super,
560 flags_mutator mutator)
561 {
562 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
563 disk_super->flags = cpu_to_le32(sb_flags);
564 }
565
566 static unsigned long set_clean_shutdown(unsigned long flags)
567 {
568 set_bit(CLEAN_SHUTDOWN, &flags);
569 return flags;
570 }
571
572 static unsigned long clear_clean_shutdown(unsigned long flags)
573 {
574 clear_bit(CLEAN_SHUTDOWN, &flags);
575 return flags;
576 }
577
578 static void read_superblock_fields(struct dm_cache_metadata *cmd,
579 struct cache_disk_superblock *disk_super)
580 {
581 cmd->version = le32_to_cpu(disk_super->version);
582 cmd->flags = le32_to_cpu(disk_super->flags);
583 cmd->root = le64_to_cpu(disk_super->mapping_root);
584 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
585 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
586 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
587 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
588 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
589 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
590 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
591 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
592 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
593 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
594 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
595
596 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
597 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
598 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
599 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
600
601 if (separate_dirty_bits(cmd))
602 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
603
604 cmd->changed = false;
605 }
606
607 /*
608 * The mutator updates the superblock flags.
609 */
610 static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
611 flags_mutator mutator)
612 {
613 int r;
614 struct cache_disk_superblock *disk_super;
615 struct dm_block *sblock;
616
617 r = superblock_lock(cmd, &sblock);
618 if (r)
619 return r;
620
621 disk_super = dm_block_data(sblock);
622 update_flags(disk_super, mutator);
623 read_superblock_fields(cmd, disk_super);
624 dm_bm_unlock(sblock);
625
626 return dm_bm_flush(cmd->bm);
627 }
628
629 static int __begin_transaction(struct dm_cache_metadata *cmd)
630 {
631 int r;
632 struct cache_disk_superblock *disk_super;
633 struct dm_block *sblock;
634
635 /*
636 * We re-read the superblock every time. Shouldn't need to do this
637 * really.
638 */
639 r = superblock_read_lock(cmd, &sblock);
640 if (r)
641 return r;
642
643 disk_super = dm_block_data(sblock);
644 read_superblock_fields(cmd, disk_super);
645 dm_bm_unlock(sblock);
646
647 return 0;
648 }
649
650 static int __commit_transaction(struct dm_cache_metadata *cmd,
651 flags_mutator mutator)
652 {
653 int r;
654 struct cache_disk_superblock *disk_super;
655 struct dm_block *sblock;
656
657 /*
658 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
659 */
660 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
661
662 if (separate_dirty_bits(cmd)) {
663 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
664 &cmd->dirty_root);
665 if (r)
666 return r;
667 }
668
669 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
670 &cmd->discard_root);
671 if (r)
672 return r;
673
674 r = dm_tm_pre_commit(cmd->tm);
675 if (r < 0)
676 return r;
677
678 r = __save_sm_root(cmd);
679 if (r)
680 return r;
681
682 r = superblock_lock(cmd, &sblock);
683 if (r)
684 return r;
685
686 disk_super = dm_block_data(sblock);
687
688 disk_super->flags = cpu_to_le32(cmd->flags);
689 if (mutator)
690 update_flags(disk_super, mutator);
691
692 disk_super->mapping_root = cpu_to_le64(cmd->root);
693 if (separate_dirty_bits(cmd))
694 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
695 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
696 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
697 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
698 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
699 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
700 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
701 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
702 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
703 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
704
705 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
706 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
707 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
708 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
709 __copy_sm_root(cmd, disk_super);
710
711 return dm_tm_commit(cmd->tm, sblock);
712 }
713
714 /*----------------------------------------------------------------*/
715
716 /*
717 * The mappings are held in a dm-array that has 64-bit values stored in
718 * little-endian format. The index is the cblock, the high 48bits of the
719 * value are the oblock and the low 16 bit the flags.
720 */
721 #define FLAGS_MASK ((1 << 16) - 1)
722
723 static __le64 pack_value(dm_oblock_t block, unsigned flags)
724 {
725 uint64_t value = from_oblock(block);
726 value <<= 16;
727 value = value | (flags & FLAGS_MASK);
728 return cpu_to_le64(value);
729 }
730
731 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
732 {
733 uint64_t value = le64_to_cpu(value_le);
734 uint64_t b = value >> 16;
735 *block = to_oblock(b);
736 *flags = value & FLAGS_MASK;
737 }
738
739 /*----------------------------------------------------------------*/
740
741 static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
742 sector_t data_block_size,
743 bool may_format_device,
744 size_t policy_hint_size,
745 unsigned metadata_version)
746 {
747 int r;
748 struct dm_cache_metadata *cmd;
749
750 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
751 if (!cmd) {
752 DMERR("could not allocate metadata struct");
753 return ERR_PTR(-ENOMEM);
754 }
755
756 cmd->version = metadata_version;
757 refcount_set(&cmd->ref_count, 1);
758 init_rwsem(&cmd->root_lock);
759 cmd->bdev = bdev;
760 cmd->data_block_size = data_block_size;
761 cmd->cache_blocks = 0;
762 cmd->policy_hint_size = policy_hint_size;
763 cmd->changed = true;
764 cmd->fail_io = false;
765
766 r = __create_persistent_data_objects(cmd, may_format_device);
767 if (r) {
768 kfree(cmd);
769 return ERR_PTR(r);
770 }
771
772 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
773 if (r < 0) {
774 dm_cache_metadata_close(cmd);
775 return ERR_PTR(r);
776 }
777
778 return cmd;
779 }
780
781 /*
782 * We keep a little list of ref counted metadata objects to prevent two
783 * different target instances creating separate bufio instances. This is
784 * an issue if a table is reloaded before the suspend.
785 */
786 static DEFINE_MUTEX(table_lock);
787 static LIST_HEAD(table);
788
789 static struct dm_cache_metadata *lookup(struct block_device *bdev)
790 {
791 struct dm_cache_metadata *cmd;
792
793 list_for_each_entry(cmd, &table, list)
794 if (cmd->bdev == bdev) {
795 refcount_inc(&cmd->ref_count);
796 return cmd;
797 }
798
799 return NULL;
800 }
801
802 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
803 sector_t data_block_size,
804 bool may_format_device,
805 size_t policy_hint_size,
806 unsigned metadata_version)
807 {
808 struct dm_cache_metadata *cmd, *cmd2;
809
810 mutex_lock(&table_lock);
811 cmd = lookup(bdev);
812 mutex_unlock(&table_lock);
813
814 if (cmd)
815 return cmd;
816
817 cmd = metadata_open(bdev, data_block_size, may_format_device,
818 policy_hint_size, metadata_version);
819 if (!IS_ERR(cmd)) {
820 mutex_lock(&table_lock);
821 cmd2 = lookup(bdev);
822 if (cmd2) {
823 mutex_unlock(&table_lock);
824 __destroy_persistent_data_objects(cmd);
825 kfree(cmd);
826 return cmd2;
827 }
828 list_add(&cmd->list, &table);
829 mutex_unlock(&table_lock);
830 }
831
832 return cmd;
833 }
834
835 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
836 {
837 if (cmd->data_block_size != data_block_size) {
838 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
839 (unsigned long long) data_block_size,
840 (unsigned long long) cmd->data_block_size);
841 return false;
842 }
843
844 return true;
845 }
846
847 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
848 sector_t data_block_size,
849 bool may_format_device,
850 size_t policy_hint_size,
851 unsigned metadata_version)
852 {
853 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
854 policy_hint_size, metadata_version);
855
856 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
857 dm_cache_metadata_close(cmd);
858 return ERR_PTR(-EINVAL);
859 }
860
861 return cmd;
862 }
863
864 void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
865 {
866 if (refcount_dec_and_test(&cmd->ref_count)) {
867 mutex_lock(&table_lock);
868 list_del(&cmd->list);
869 mutex_unlock(&table_lock);
870
871 if (!cmd->fail_io)
872 __destroy_persistent_data_objects(cmd);
873 kfree(cmd);
874 }
875 }
876
877 /*
878 * Checks that the given cache block is either unmapped or clean.
879 */
880 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
881 bool *result)
882 {
883 int r;
884 __le64 value;
885 dm_oblock_t ob;
886 unsigned flags;
887
888 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
889 if (r)
890 return r;
891
892 unpack_value(value, &ob, &flags);
893 *result = !((flags & M_VALID) && (flags & M_DIRTY));
894
895 return 0;
896 }
897
898 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
899 dm_cblock_t begin, dm_cblock_t end,
900 bool *result)
901 {
902 int r;
903 *result = true;
904
905 while (begin != end) {
906 r = block_clean_combined_dirty(cmd, begin, result);
907 if (r) {
908 DMERR("block_clean_combined_dirty failed");
909 return r;
910 }
911
912 if (!*result) {
913 DMERR("cache block %llu is dirty",
914 (unsigned long long) from_cblock(begin));
915 return 0;
916 }
917
918 begin = to_cblock(from_cblock(begin) + 1);
919 }
920
921 return 0;
922 }
923
924 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
925 dm_cblock_t begin, dm_cblock_t end,
926 bool *result)
927 {
928 int r;
929 bool dirty_flag;
930 *result = true;
931
932 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
933 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
934 if (r) {
935 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__);
936 return r;
937 }
938
939 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin));
940 if (r) {
941 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
942 dm_bitset_cursor_end(&cmd->dirty_cursor);
943 return r;
944 }
945
946 while (begin != end) {
947 /*
948 * We assume that unmapped blocks have their dirty bit
949 * cleared.
950 */
951 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor);
952 if (dirty_flag) {
953 DMERR("%s: cache block %llu is dirty", __func__,
954 (unsigned long long) from_cblock(begin));
955 dm_bitset_cursor_end(&cmd->dirty_cursor);
956 *result = false;
957 return 0;
958 }
959
960 begin = to_cblock(from_cblock(begin) + 1);
961 if (begin == end)
962 break;
963
964 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
965 if (r) {
966 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
967 dm_bitset_cursor_end(&cmd->dirty_cursor);
968 return r;
969 }
970 }
971
972 dm_bitset_cursor_end(&cmd->dirty_cursor);
973
974 return 0;
975 }
976
977 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
978 dm_cblock_t begin, dm_cblock_t end,
979 bool *result)
980 {
981 if (separate_dirty_bits(cmd))
982 return blocks_are_clean_separate_dirty(cmd, begin, end, result);
983 else
984 return blocks_are_clean_combined_dirty(cmd, begin, end, result);
985 }
986
987 static bool cmd_write_lock(struct dm_cache_metadata *cmd)
988 {
989 down_write(&cmd->root_lock);
990 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
991 up_write(&cmd->root_lock);
992 return false;
993 }
994 return true;
995 }
996
997 #define WRITE_LOCK(cmd) \
998 do { \
999 if (!cmd_write_lock((cmd))) \
1000 return -EINVAL; \
1001 } while(0)
1002
1003 #define WRITE_LOCK_VOID(cmd) \
1004 do { \
1005 if (!cmd_write_lock((cmd))) \
1006 return; \
1007 } while(0)
1008
1009 #define WRITE_UNLOCK(cmd) \
1010 up_write(&(cmd)->root_lock)
1011
1012 static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1013 {
1014 down_read(&cmd->root_lock);
1015 if (cmd->fail_io) {
1016 up_read(&cmd->root_lock);
1017 return false;
1018 }
1019 return true;
1020 }
1021
1022 #define READ_LOCK(cmd) \
1023 do { \
1024 if (!cmd_read_lock((cmd))) \
1025 return -EINVAL; \
1026 } while(0)
1027
1028 #define READ_LOCK_VOID(cmd) \
1029 do { \
1030 if (!cmd_read_lock((cmd))) \
1031 return; \
1032 } while(0)
1033
1034 #define READ_UNLOCK(cmd) \
1035 up_read(&(cmd)->root_lock)
1036
1037 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1038 {
1039 int r;
1040 bool clean;
1041 __le64 null_mapping = pack_value(0, 0);
1042
1043 WRITE_LOCK(cmd);
1044 __dm_bless_for_disk(&null_mapping);
1045
1046 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1047 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
1048 if (r) {
1049 __dm_unbless_for_disk(&null_mapping);
1050 goto out;
1051 }
1052
1053 if (!clean) {
1054 DMERR("unable to shrink cache due to dirty blocks");
1055 r = -EINVAL;
1056 __dm_unbless_for_disk(&null_mapping);
1057 goto out;
1058 }
1059 }
1060
1061 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1062 from_cblock(new_cache_size),
1063 &null_mapping, &cmd->root);
1064 if (r)
1065 goto out;
1066
1067 if (separate_dirty_bits(cmd)) {
1068 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1069 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1070 false, &cmd->dirty_root);
1071 if (r)
1072 goto out;
1073 }
1074
1075 cmd->cache_blocks = new_cache_size;
1076 cmd->changed = true;
1077
1078 out:
1079 WRITE_UNLOCK(cmd);
1080
1081 return r;
1082 }
1083
1084 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1085 sector_t discard_block_size,
1086 dm_dblock_t new_nr_entries)
1087 {
1088 int r;
1089
1090 WRITE_LOCK(cmd);
1091 r = dm_bitset_resize(&cmd->discard_info,
1092 cmd->discard_root,
1093 from_dblock(cmd->discard_nr_blocks),
1094 from_dblock(new_nr_entries),
1095 false, &cmd->discard_root);
1096 if (!r) {
1097 cmd->discard_block_size = discard_block_size;
1098 cmd->discard_nr_blocks = new_nr_entries;
1099 }
1100
1101 cmd->changed = true;
1102 WRITE_UNLOCK(cmd);
1103
1104 return r;
1105 }
1106
1107 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1108 {
1109 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
1110 from_dblock(b), &cmd->discard_root);
1111 }
1112
1113 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1114 {
1115 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
1116 from_dblock(b), &cmd->discard_root);
1117 }
1118
1119 static int __discard(struct dm_cache_metadata *cmd,
1120 dm_dblock_t dblock, bool discard)
1121 {
1122 int r;
1123
1124 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1125 if (r)
1126 return r;
1127
1128 cmd->changed = true;
1129 return 0;
1130 }
1131
1132 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1133 dm_dblock_t dblock, bool discard)
1134 {
1135 int r;
1136
1137 WRITE_LOCK(cmd);
1138 r = __discard(cmd, dblock, discard);
1139 WRITE_UNLOCK(cmd);
1140
1141 return r;
1142 }
1143
1144 static int __load_discards(struct dm_cache_metadata *cmd,
1145 load_discard_fn fn, void *context)
1146 {
1147 int r = 0;
1148 uint32_t b;
1149 struct dm_bitset_cursor c;
1150
1151 if (from_dblock(cmd->discard_nr_blocks) == 0)
1152 /* nothing to do */
1153 return 0;
1154
1155 if (cmd->clean_when_opened) {
1156 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1157 if (r)
1158 return r;
1159
1160 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1161 from_dblock(cmd->discard_nr_blocks), &c);
1162 if (r)
1163 return r;
1164
1165 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1166 r = fn(context, cmd->discard_block_size, to_dblock(b),
1167 dm_bitset_cursor_get_value(&c));
1168 if (r)
1169 break;
1170 }
1171
1172 dm_bitset_cursor_end(&c);
1173
1174 } else {
1175 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1176 r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1177 if (r)
1178 return r;
1179 }
1180 }
1181
1182 return r;
1183 }
1184
1185 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1186 load_discard_fn fn, void *context)
1187 {
1188 int r;
1189
1190 READ_LOCK(cmd);
1191 r = __load_discards(cmd, fn, context);
1192 READ_UNLOCK(cmd);
1193
1194 return r;
1195 }
1196
1197 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1198 {
1199 READ_LOCK(cmd);
1200 *result = cmd->cache_blocks;
1201 READ_UNLOCK(cmd);
1202
1203 return 0;
1204 }
1205
1206 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1207 {
1208 int r;
1209 __le64 value = pack_value(0, 0);
1210
1211 __dm_bless_for_disk(&value);
1212 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1213 &value, &cmd->root);
1214 if (r)
1215 return r;
1216
1217 cmd->changed = true;
1218 return 0;
1219 }
1220
1221 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1222 {
1223 int r;
1224
1225 WRITE_LOCK(cmd);
1226 r = __remove(cmd, cblock);
1227 WRITE_UNLOCK(cmd);
1228
1229 return r;
1230 }
1231
1232 static int __insert(struct dm_cache_metadata *cmd,
1233 dm_cblock_t cblock, dm_oblock_t oblock)
1234 {
1235 int r;
1236 __le64 value = pack_value(oblock, M_VALID);
1237 __dm_bless_for_disk(&value);
1238
1239 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1240 &value, &cmd->root);
1241 if (r)
1242 return r;
1243
1244 cmd->changed = true;
1245 return 0;
1246 }
1247
1248 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1249 dm_cblock_t cblock, dm_oblock_t oblock)
1250 {
1251 int r;
1252
1253 WRITE_LOCK(cmd);
1254 r = __insert(cmd, cblock, oblock);
1255 WRITE_UNLOCK(cmd);
1256
1257 return r;
1258 }
1259
1260 struct thunk {
1261 load_mapping_fn fn;
1262 void *context;
1263
1264 struct dm_cache_metadata *cmd;
1265 bool respect_dirty_flags;
1266 bool hints_valid;
1267 };
1268
1269 static bool policy_unchanged(struct dm_cache_metadata *cmd,
1270 struct dm_cache_policy *policy)
1271 {
1272 const char *policy_name = dm_cache_policy_get_name(policy);
1273 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1274 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1275
1276 /*
1277 * Ensure policy names match.
1278 */
1279 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1280 return false;
1281
1282 /*
1283 * Ensure policy major versions match.
1284 */
1285 if (cmd->policy_version[0] != policy_version[0])
1286 return false;
1287
1288 /*
1289 * Ensure policy hint sizes match.
1290 */
1291 if (cmd->policy_hint_size != policy_hint_size)
1292 return false;
1293
1294 return true;
1295 }
1296
1297 static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1298 {
1299 return cmd->hint_root && cmd->policy_hint_size;
1300 }
1301
1302 static bool hints_array_available(struct dm_cache_metadata *cmd,
1303 struct dm_cache_policy *policy)
1304 {
1305 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1306 hints_array_initialized(cmd);
1307 }
1308
1309 static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1310 uint64_t cb, bool hints_valid,
1311 struct dm_array_cursor *mapping_cursor,
1312 struct dm_array_cursor *hint_cursor,
1313 load_mapping_fn fn, void *context)
1314 {
1315 int r = 0;
1316
1317 __le64 mapping;
1318 __le32 hint = 0;
1319
1320 __le64 *mapping_value_le;
1321 __le32 *hint_value_le;
1322
1323 dm_oblock_t oblock;
1324 unsigned flags;
1325
1326 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1327 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1328 unpack_value(mapping, &oblock, &flags);
1329
1330 if (flags & M_VALID) {
1331 if (hints_valid) {
1332 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1333 memcpy(&hint, hint_value_le, sizeof(hint));
1334 }
1335
1336 r = fn(context, oblock, to_cblock(cb), flags & M_DIRTY,
1337 le32_to_cpu(hint), hints_valid);
1338 if (r) {
1339 DMERR("policy couldn't load cache block %llu",
1340 (unsigned long long) from_cblock(to_cblock(cb)));
1341 }
1342 }
1343
1344 return r;
1345 }
1346
1347 static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1348 uint64_t cb, bool hints_valid,
1349 struct dm_array_cursor *mapping_cursor,
1350 struct dm_array_cursor *hint_cursor,
1351 struct dm_bitset_cursor *dirty_cursor,
1352 load_mapping_fn fn, void *context)
1353 {
1354 int r = 0;
1355
1356 __le64 mapping;
1357 __le32 hint = 0;
1358
1359 __le64 *mapping_value_le;
1360 __le32 *hint_value_le;
1361
1362 dm_oblock_t oblock;
1363 unsigned flags;
1364 bool dirty;
1365
1366 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1367 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1368 unpack_value(mapping, &oblock, &flags);
1369
1370 if (flags & M_VALID) {
1371 if (hints_valid) {
1372 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1373 memcpy(&hint, hint_value_le, sizeof(hint));
1374 }
1375
1376 dirty = dm_bitset_cursor_get_value(dirty_cursor);
1377 r = fn(context, oblock, to_cblock(cb), dirty,
1378 le32_to_cpu(hint), hints_valid);
1379 if (r) {
1380 DMERR("policy couldn't load cache block %llu",
1381 (unsigned long long) from_cblock(to_cblock(cb)));
1382 }
1383 }
1384
1385 return r;
1386 }
1387
1388 static int __load_mappings(struct dm_cache_metadata *cmd,
1389 struct dm_cache_policy *policy,
1390 load_mapping_fn fn, void *context)
1391 {
1392 int r;
1393 uint64_t cb;
1394
1395 bool hints_valid = hints_array_available(cmd, policy);
1396
1397 if (from_cblock(cmd->cache_blocks) == 0)
1398 /* Nothing to do */
1399 return 0;
1400
1401 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1402 if (r)
1403 return r;
1404
1405 if (hints_valid) {
1406 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1407 if (r) {
1408 dm_array_cursor_end(&cmd->mapping_cursor);
1409 return r;
1410 }
1411 }
1412
1413 if (separate_dirty_bits(cmd)) {
1414 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1415 from_cblock(cmd->cache_blocks),
1416 &cmd->dirty_cursor);
1417 if (r) {
1418 dm_array_cursor_end(&cmd->hint_cursor);
1419 dm_array_cursor_end(&cmd->mapping_cursor);
1420 return r;
1421 }
1422 }
1423
1424 for (cb = 0; ; cb++) {
1425 if (separate_dirty_bits(cmd))
1426 r = __load_mapping_v2(cmd, cb, hints_valid,
1427 &cmd->mapping_cursor,
1428 &cmd->hint_cursor,
1429 &cmd->dirty_cursor,
1430 fn, context);
1431 else
1432 r = __load_mapping_v1(cmd, cb, hints_valid,
1433 &cmd->mapping_cursor, &cmd->hint_cursor,
1434 fn, context);
1435 if (r)
1436 goto out;
1437
1438 /*
1439 * We need to break out before we move the cursors.
1440 */
1441 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1442 break;
1443
1444 r = dm_array_cursor_next(&cmd->mapping_cursor);
1445 if (r) {
1446 DMERR("dm_array_cursor_next for mapping failed");
1447 goto out;
1448 }
1449
1450 if (hints_valid) {
1451 r = dm_array_cursor_next(&cmd->hint_cursor);
1452 if (r) {
1453 DMERR("dm_array_cursor_next for hint failed");
1454 goto out;
1455 }
1456 }
1457
1458 if (separate_dirty_bits(cmd)) {
1459 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1460 if (r) {
1461 DMERR("dm_bitset_cursor_next for dirty failed");
1462 goto out;
1463 }
1464 }
1465 }
1466 out:
1467 dm_array_cursor_end(&cmd->mapping_cursor);
1468 if (hints_valid)
1469 dm_array_cursor_end(&cmd->hint_cursor);
1470
1471 if (separate_dirty_bits(cmd))
1472 dm_bitset_cursor_end(&cmd->dirty_cursor);
1473
1474 return r;
1475 }
1476
1477 int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1478 struct dm_cache_policy *policy,
1479 load_mapping_fn fn, void *context)
1480 {
1481 int r;
1482
1483 READ_LOCK(cmd);
1484 r = __load_mappings(cmd, policy, fn, context);
1485 READ_UNLOCK(cmd);
1486
1487 return r;
1488 }
1489
1490 static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1491 {
1492 int r = 0;
1493 __le64 value;
1494 dm_oblock_t oblock;
1495 unsigned flags;
1496
1497 memcpy(&value, leaf, sizeof(value));
1498 unpack_value(value, &oblock, &flags);
1499
1500 return r;
1501 }
1502
1503 static int __dump_mappings(struct dm_cache_metadata *cmd)
1504 {
1505 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1506 }
1507
1508 void dm_cache_dump(struct dm_cache_metadata *cmd)
1509 {
1510 READ_LOCK_VOID(cmd);
1511 __dump_mappings(cmd);
1512 READ_UNLOCK(cmd);
1513 }
1514
1515 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1516 {
1517 int r;
1518
1519 READ_LOCK(cmd);
1520 r = cmd->changed;
1521 READ_UNLOCK(cmd);
1522
1523 return r;
1524 }
1525
1526 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1527 {
1528 int r;
1529 unsigned flags;
1530 dm_oblock_t oblock;
1531 __le64 value;
1532
1533 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1534 if (r)
1535 return r;
1536
1537 unpack_value(value, &oblock, &flags);
1538
1539 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1540 /* nothing to be done */
1541 return 0;
1542
1543 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1544 __dm_bless_for_disk(&value);
1545
1546 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1547 &value, &cmd->root);
1548 if (r)
1549 return r;
1550
1551 cmd->changed = true;
1552 return 0;
1553
1554 }
1555
1556 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1557 {
1558 int r;
1559 unsigned i;
1560 for (i = 0; i < nr_bits; i++) {
1561 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1562 if (r)
1563 return r;
1564 }
1565
1566 return 0;
1567 }
1568
1569 static int is_dirty_callback(uint32_t index, bool *value, void *context)
1570 {
1571 unsigned long *bits = context;
1572 *value = test_bit(index, bits);
1573 return 0;
1574 }
1575
1576 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1577 {
1578 int r = 0;
1579
1580 /* nr_bits is really just a sanity check */
1581 if (nr_bits != from_cblock(cmd->cache_blocks)) {
1582 DMERR("dirty bitset is wrong size");
1583 return -EINVAL;
1584 }
1585
1586 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1587 if (r)
1588 return r;
1589
1590 cmd->changed = true;
1591 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1592 }
1593
1594 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1595 unsigned nr_bits,
1596 unsigned long *bits)
1597 {
1598 int r;
1599
1600 WRITE_LOCK(cmd);
1601 if (separate_dirty_bits(cmd))
1602 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1603 else
1604 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1605 WRITE_UNLOCK(cmd);
1606
1607 return r;
1608 }
1609
1610 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1611 struct dm_cache_statistics *stats)
1612 {
1613 READ_LOCK_VOID(cmd);
1614 *stats = cmd->stats;
1615 READ_UNLOCK(cmd);
1616 }
1617
1618 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1619 struct dm_cache_statistics *stats)
1620 {
1621 WRITE_LOCK_VOID(cmd);
1622 cmd->stats = *stats;
1623 WRITE_UNLOCK(cmd);
1624 }
1625
1626 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1627 {
1628 int r = -EINVAL;
1629 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1630 clear_clean_shutdown);
1631
1632 WRITE_LOCK(cmd);
1633 if (cmd->fail_io)
1634 goto out;
1635
1636 r = __commit_transaction(cmd, mutator);
1637 if (r)
1638 goto out;
1639
1640 r = __begin_transaction(cmd);
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 if (!cmd->fail_io)
1653 r = dm_sm_get_nr_free(cmd->metadata_sm, result);
1654 READ_UNLOCK(cmd);
1655
1656 return r;
1657 }
1658
1659 int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
1660 dm_block_t *result)
1661 {
1662 int r = -EINVAL;
1663
1664 READ_LOCK(cmd);
1665 if (!cmd->fail_io)
1666 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1667 READ_UNLOCK(cmd);
1668
1669 return r;
1670 }
1671
1672 /*----------------------------------------------------------------*/
1673
1674 static int get_hint(uint32_t index, void *value_le, void *context)
1675 {
1676 uint32_t value;
1677 struct dm_cache_policy *policy = context;
1678
1679 value = policy_get_hint(policy, to_cblock(index));
1680 *((__le32 *) value_le) = cpu_to_le32(value);
1681
1682 return 0;
1683 }
1684
1685 /*
1686 * It's quicker to always delete the hint array, and recreate with
1687 * dm_array_new().
1688 */
1689 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1690 {
1691 int r;
1692 size_t hint_size;
1693 const char *policy_name = dm_cache_policy_get_name(policy);
1694 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1695
1696 if (!policy_name[0] ||
1697 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1698 return -EINVAL;
1699
1700 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1701 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1702
1703 hint_size = dm_cache_policy_get_hint_size(policy);
1704 if (!hint_size)
1705 return 0; /* short-circuit hints initialization */
1706 cmd->policy_hint_size = hint_size;
1707
1708 if (cmd->hint_root) {
1709 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1710 if (r)
1711 return r;
1712 }
1713
1714 return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1715 from_cblock(cmd->cache_blocks),
1716 get_hint, policy);
1717 }
1718
1719 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1720 {
1721 int r;
1722
1723 WRITE_LOCK(cmd);
1724 r = write_hints(cmd, policy);
1725 WRITE_UNLOCK(cmd);
1726
1727 return r;
1728 }
1729
1730 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1731 {
1732 int r;
1733
1734 READ_LOCK(cmd);
1735 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1736 READ_UNLOCK(cmd);
1737
1738 return r;
1739 }
1740
1741 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1742 {
1743 WRITE_LOCK_VOID(cmd);
1744 dm_bm_set_read_only(cmd->bm);
1745 WRITE_UNLOCK(cmd);
1746 }
1747
1748 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1749 {
1750 WRITE_LOCK_VOID(cmd);
1751 dm_bm_set_read_write(cmd->bm);
1752 WRITE_UNLOCK(cmd);
1753 }
1754
1755 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1756 {
1757 int r;
1758 struct dm_block *sblock;
1759 struct cache_disk_superblock *disk_super;
1760
1761 WRITE_LOCK(cmd);
1762 set_bit(NEEDS_CHECK, &cmd->flags);
1763
1764 r = superblock_lock(cmd, &sblock);
1765 if (r) {
1766 DMERR("couldn't read superblock");
1767 goto out;
1768 }
1769
1770 disk_super = dm_block_data(sblock);
1771 disk_super->flags = cpu_to_le32(cmd->flags);
1772
1773 dm_bm_unlock(sblock);
1774
1775 out:
1776 WRITE_UNLOCK(cmd);
1777 return r;
1778 }
1779
1780 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1781 {
1782 READ_LOCK(cmd);
1783 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1784 READ_UNLOCK(cmd);
1785
1786 return 0;
1787 }
1788
1789 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1790 {
1791 int r;
1792
1793 WRITE_LOCK(cmd);
1794 __destroy_persistent_data_objects(cmd);
1795 r = __create_persistent_data_objects(cmd, false);
1796 if (r)
1797 cmd->fail_io = true;
1798 WRITE_UNLOCK(cmd);
1799
1800 return r;
1801 }
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