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[mirror_ubuntu-artful-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
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 /*
31 * 3 for btree insert +
32 * 2 for btree lookup used within space map
33 */
34 #define CACHE_MAX_CONCURRENT_LOCKS 5
35 #define SPACE_MAP_ROOT_SIZE 128
36
37 enum superblock_flag_bits {
38 /* for spotting crashes that would invalidate the dirty bitset */
39 CLEAN_SHUTDOWN,
40 /* metadata must be checked using the tools */
41 NEEDS_CHECK,
42 };
43
44 /*
45 * Each mapping from cache block -> origin block carries a set of flags.
46 */
47 enum mapping_bits {
48 /*
49 * A valid mapping. Because we're using an array we clear this
50 * flag for an non existant mapping.
51 */
52 M_VALID = 1,
53
54 /*
55 * The data on the cache is different from that on the origin.
56 * This flag is only used by metadata format 1.
57 */
58 M_DIRTY = 2
59 };
60
61 struct cache_disk_superblock {
62 __le32 csum;
63 __le32 flags;
64 __le64 blocknr;
65
66 __u8 uuid[16];
67 __le64 magic;
68 __le32 version;
69
70 __u8 policy_name[CACHE_POLICY_NAME_SIZE];
71 __le32 policy_hint_size;
72
73 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
74 __le64 mapping_root;
75 __le64 hint_root;
76
77 __le64 discard_root;
78 __le64 discard_block_size;
79 __le64 discard_nr_blocks;
80
81 __le32 data_block_size;
82 __le32 metadata_block_size;
83 __le32 cache_blocks;
84
85 __le32 compat_flags;
86 __le32 compat_ro_flags;
87 __le32 incompat_flags;
88
89 __le32 read_hits;
90 __le32 read_misses;
91 __le32 write_hits;
92 __le32 write_misses;
93
94 __le32 policy_version[CACHE_POLICY_VERSION_SIZE];
95
96 /*
97 * Metadata format 2 fields.
98 */
99 __le64 dirty_root;
100 } __packed;
101
102 struct dm_cache_metadata {
103 atomic_t ref_count;
104 struct list_head list;
105
106 unsigned version;
107 struct block_device *bdev;
108 struct dm_block_manager *bm;
109 struct dm_space_map *metadata_sm;
110 struct dm_transaction_manager *tm;
111
112 struct dm_array_info info;
113 struct dm_array_info hint_info;
114 struct dm_disk_bitset discard_info;
115
116 struct rw_semaphore root_lock;
117 unsigned long flags;
118 dm_block_t root;
119 dm_block_t hint_root;
120 dm_block_t discard_root;
121
122 sector_t discard_block_size;
123 dm_dblock_t discard_nr_blocks;
124
125 sector_t data_block_size;
126 dm_cblock_t cache_blocks;
127 bool changed:1;
128 bool clean_when_opened:1;
129
130 char policy_name[CACHE_POLICY_NAME_SIZE];
131 unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
132 size_t policy_hint_size;
133 struct dm_cache_statistics stats;
134
135 /*
136 * Reading the space map root can fail, so we read it into this
137 * buffer before the superblock is locked and updated.
138 */
139 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
140
141 /*
142 * Set if a transaction has to be aborted but the attempt to roll
143 * back to the previous (good) transaction failed. The only
144 * metadata operation permissible in this state is the closing of
145 * the device.
146 */
147 bool fail_io:1;
148
149 /*
150 * Metadata format 2 fields.
151 */
152 dm_block_t dirty_root;
153 struct dm_disk_bitset dirty_info;
154
155 /*
156 * These structures are used when loading metadata. They're too
157 * big to put on the stack.
158 */
159 struct dm_array_cursor mapping_cursor;
160 struct dm_array_cursor hint_cursor;
161 struct dm_bitset_cursor dirty_cursor;
162 };
163
164 /*-------------------------------------------------------------------
165 * superblock validator
166 *-----------------------------------------------------------------*/
167
168 #define SUPERBLOCK_CSUM_XOR 9031977
169
170 static void sb_prepare_for_write(struct dm_block_validator *v,
171 struct dm_block *b,
172 size_t sb_block_size)
173 {
174 struct cache_disk_superblock *disk_super = dm_block_data(b);
175
176 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
177 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
178 sb_block_size - sizeof(__le32),
179 SUPERBLOCK_CSUM_XOR));
180 }
181
182 static int check_metadata_version(struct cache_disk_superblock *disk_super)
183 {
184 uint32_t metadata_version = le32_to_cpu(disk_super->version);
185
186 if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
187 DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
188 metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
189 return -EINVAL;
190 }
191
192 return 0;
193 }
194
195 static int sb_check(struct dm_block_validator *v,
196 struct dm_block *b,
197 size_t sb_block_size)
198 {
199 struct cache_disk_superblock *disk_super = dm_block_data(b);
200 __le32 csum_le;
201
202 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
203 DMERR("sb_check failed: blocknr %llu: wanted %llu",
204 le64_to_cpu(disk_super->blocknr),
205 (unsigned long long)dm_block_location(b));
206 return -ENOTBLK;
207 }
208
209 if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) {
210 DMERR("sb_check failed: magic %llu: wanted %llu",
211 le64_to_cpu(disk_super->magic),
212 (unsigned long long)CACHE_SUPERBLOCK_MAGIC);
213 return -EILSEQ;
214 }
215
216 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
217 sb_block_size - sizeof(__le32),
218 SUPERBLOCK_CSUM_XOR));
219 if (csum_le != disk_super->csum) {
220 DMERR("sb_check failed: csum %u: wanted %u",
221 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
222 return -EILSEQ;
223 }
224
225 return check_metadata_version(disk_super);
226 }
227
228 static struct dm_block_validator sb_validator = {
229 .name = "superblock",
230 .prepare_for_write = sb_prepare_for_write,
231 .check = sb_check
232 };
233
234 /*----------------------------------------------------------------*/
235
236 static int superblock_read_lock(struct dm_cache_metadata *cmd,
237 struct dm_block **sblock)
238 {
239 return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
240 &sb_validator, sblock);
241 }
242
243 static int superblock_lock_zero(struct dm_cache_metadata *cmd,
244 struct dm_block **sblock)
245 {
246 return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
247 &sb_validator, sblock);
248 }
249
250 static int superblock_lock(struct dm_cache_metadata *cmd,
251 struct dm_block **sblock)
252 {
253 return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
254 &sb_validator, sblock);
255 }
256
257 /*----------------------------------------------------------------*/
258
259 static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
260 {
261 int r;
262 unsigned i;
263 struct dm_block *b;
264 __le64 *data_le, zero = cpu_to_le64(0);
265 unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
266
267 /*
268 * We can't use a validator here - it may be all zeroes.
269 */
270 r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b);
271 if (r)
272 return r;
273
274 data_le = dm_block_data(b);
275 *result = true;
276 for (i = 0; i < sb_block_size; i++) {
277 if (data_le[i] != zero) {
278 *result = false;
279 break;
280 }
281 }
282
283 dm_bm_unlock(b);
284
285 return 0;
286 }
287
288 static void __setup_mapping_info(struct dm_cache_metadata *cmd)
289 {
290 struct dm_btree_value_type vt;
291
292 vt.context = NULL;
293 vt.size = sizeof(__le64);
294 vt.inc = NULL;
295 vt.dec = NULL;
296 vt.equal = NULL;
297 dm_array_info_init(&cmd->info, cmd->tm, &vt);
298
299 if (cmd->policy_hint_size) {
300 vt.size = sizeof(__le32);
301 dm_array_info_init(&cmd->hint_info, cmd->tm, &vt);
302 }
303 }
304
305 static int __save_sm_root(struct dm_cache_metadata *cmd)
306 {
307 int r;
308 size_t metadata_len;
309
310 r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
311 if (r < 0)
312 return r;
313
314 return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
315 metadata_len);
316 }
317
318 static void __copy_sm_root(struct dm_cache_metadata *cmd,
319 struct cache_disk_superblock *disk_super)
320 {
321 memcpy(&disk_super->metadata_space_map_root,
322 &cmd->metadata_space_map_root,
323 sizeof(cmd->metadata_space_map_root));
324 }
325
326 static bool separate_dirty_bits(struct dm_cache_metadata *cmd)
327 {
328 return cmd->version >= 2;
329 }
330
331 static int __write_initial_superblock(struct dm_cache_metadata *cmd)
332 {
333 int r;
334 struct dm_block *sblock;
335 struct cache_disk_superblock *disk_super;
336 sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
337
338 /* FIXME: see if we can lose the max sectors limit */
339 if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
340 bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
341
342 r = dm_tm_pre_commit(cmd->tm);
343 if (r < 0)
344 return r;
345
346 /*
347 * dm_sm_copy_root() can fail. So we need to do it before we start
348 * updating the superblock.
349 */
350 r = __save_sm_root(cmd);
351 if (r)
352 return r;
353
354 r = superblock_lock_zero(cmd, &sblock);
355 if (r)
356 return r;
357
358 disk_super = dm_block_data(sblock);
359 disk_super->flags = 0;
360 memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
361 disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
362 disk_super->version = cpu_to_le32(cmd->version);
363 memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
364 memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
365 disk_super->policy_hint_size = 0;
366
367 __copy_sm_root(cmd, disk_super);
368
369 disk_super->mapping_root = cpu_to_le64(cmd->root);
370 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
371 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
372 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
373 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
374 disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
375 disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
376 disk_super->cache_blocks = cpu_to_le32(0);
377
378 disk_super->read_hits = cpu_to_le32(0);
379 disk_super->read_misses = cpu_to_le32(0);
380 disk_super->write_hits = cpu_to_le32(0);
381 disk_super->write_misses = cpu_to_le32(0);
382
383 if (separate_dirty_bits(cmd))
384 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
385
386 return dm_tm_commit(cmd->tm, sblock);
387 }
388
389 static int __format_metadata(struct dm_cache_metadata *cmd)
390 {
391 int r;
392
393 r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
394 &cmd->tm, &cmd->metadata_sm);
395 if (r < 0) {
396 DMERR("tm_create_with_sm failed");
397 return r;
398 }
399
400 __setup_mapping_info(cmd);
401
402 r = dm_array_empty(&cmd->info, &cmd->root);
403 if (r < 0)
404 goto bad;
405
406 if (separate_dirty_bits(cmd)) {
407 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
408 r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root);
409 if (r < 0)
410 goto bad;
411 }
412
413 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
414 r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
415 if (r < 0)
416 goto bad;
417
418 cmd->discard_block_size = 0;
419 cmd->discard_nr_blocks = 0;
420
421 r = __write_initial_superblock(cmd);
422 if (r)
423 goto bad;
424
425 cmd->clean_when_opened = true;
426 return 0;
427
428 bad:
429 dm_tm_destroy(cmd->tm);
430 dm_sm_destroy(cmd->metadata_sm);
431
432 return r;
433 }
434
435 static int __check_incompat_features(struct cache_disk_superblock *disk_super,
436 struct dm_cache_metadata *cmd)
437 {
438 uint32_t incompat_flags, features;
439
440 incompat_flags = le32_to_cpu(disk_super->incompat_flags);
441 features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
442 if (features) {
443 DMERR("could not access metadata due to unsupported optional features (%lx).",
444 (unsigned long)features);
445 return -EINVAL;
446 }
447
448 /*
449 * Check for read-only metadata to skip the following RDWR checks.
450 */
451 if (get_disk_ro(cmd->bdev->bd_disk))
452 return 0;
453
454 features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP;
455 if (features) {
456 DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
457 (unsigned long)features);
458 return -EINVAL;
459 }
460
461 return 0;
462 }
463
464 static int __open_metadata(struct dm_cache_metadata *cmd)
465 {
466 int r;
467 struct dm_block *sblock;
468 struct cache_disk_superblock *disk_super;
469 unsigned long sb_flags;
470
471 r = superblock_read_lock(cmd, &sblock);
472 if (r < 0) {
473 DMERR("couldn't read lock superblock");
474 return r;
475 }
476
477 disk_super = dm_block_data(sblock);
478
479 /* Verify the data block size hasn't changed */
480 if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) {
481 DMERR("changing the data block size (from %u to %llu) is not supported",
482 le32_to_cpu(disk_super->data_block_size),
483 (unsigned long long)cmd->data_block_size);
484 r = -EINVAL;
485 goto bad;
486 }
487
488 r = __check_incompat_features(disk_super, cmd);
489 if (r < 0)
490 goto bad;
491
492 r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
493 disk_super->metadata_space_map_root,
494 sizeof(disk_super->metadata_space_map_root),
495 &cmd->tm, &cmd->metadata_sm);
496 if (r < 0) {
497 DMERR("tm_open_with_sm failed");
498 goto bad;
499 }
500
501 __setup_mapping_info(cmd);
502 dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
503 dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
504 sb_flags = le32_to_cpu(disk_super->flags);
505 cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
506 dm_bm_unlock(sblock);
507
508 return 0;
509
510 bad:
511 dm_bm_unlock(sblock);
512 return r;
513 }
514
515 static int __open_or_format_metadata(struct dm_cache_metadata *cmd,
516 bool format_device)
517 {
518 int r;
519 bool unformatted = false;
520
521 r = __superblock_all_zeroes(cmd->bm, &unformatted);
522 if (r)
523 return r;
524
525 if (unformatted)
526 return format_device ? __format_metadata(cmd) : -EPERM;
527
528 return __open_metadata(cmd);
529 }
530
531 static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
532 bool may_format_device)
533 {
534 int r;
535 cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
536 CACHE_MAX_CONCURRENT_LOCKS);
537 if (IS_ERR(cmd->bm)) {
538 DMERR("could not create block manager");
539 return PTR_ERR(cmd->bm);
540 }
541
542 r = __open_or_format_metadata(cmd, may_format_device);
543 if (r)
544 dm_block_manager_destroy(cmd->bm);
545
546 return r;
547 }
548
549 static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
550 {
551 dm_sm_destroy(cmd->metadata_sm);
552 dm_tm_destroy(cmd->tm);
553 dm_block_manager_destroy(cmd->bm);
554 }
555
556 typedef unsigned long (*flags_mutator)(unsigned long);
557
558 static void update_flags(struct cache_disk_superblock *disk_super,
559 flags_mutator mutator)
560 {
561 uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags));
562 disk_super->flags = cpu_to_le32(sb_flags);
563 }
564
565 static unsigned long set_clean_shutdown(unsigned long flags)
566 {
567 set_bit(CLEAN_SHUTDOWN, &flags);
568 return flags;
569 }
570
571 static unsigned long clear_clean_shutdown(unsigned long flags)
572 {
573 clear_bit(CLEAN_SHUTDOWN, &flags);
574 return flags;
575 }
576
577 static void read_superblock_fields(struct dm_cache_metadata *cmd,
578 struct cache_disk_superblock *disk_super)
579 {
580 cmd->version = le32_to_cpu(disk_super->version);
581 cmd->flags = le32_to_cpu(disk_super->flags);
582 cmd->root = le64_to_cpu(disk_super->mapping_root);
583 cmd->hint_root = le64_to_cpu(disk_super->hint_root);
584 cmd->discard_root = le64_to_cpu(disk_super->discard_root);
585 cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
586 cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
587 cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
588 cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
589 strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
590 cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]);
591 cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]);
592 cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]);
593 cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size);
594
595 cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits);
596 cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses);
597 cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
598 cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
599
600 if (separate_dirty_bits(cmd))
601 cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
602
603 cmd->changed = false;
604 }
605
606 /*
607 * The mutator updates the superblock flags.
608 */
609 static int __begin_transaction_flags(struct dm_cache_metadata *cmd,
610 flags_mutator mutator)
611 {
612 int r;
613 struct cache_disk_superblock *disk_super;
614 struct dm_block *sblock;
615
616 r = superblock_lock(cmd, &sblock);
617 if (r)
618 return r;
619
620 disk_super = dm_block_data(sblock);
621 update_flags(disk_super, mutator);
622 read_superblock_fields(cmd, disk_super);
623 dm_bm_unlock(sblock);
624
625 return dm_bm_flush(cmd->bm);
626 }
627
628 static int __begin_transaction(struct dm_cache_metadata *cmd)
629 {
630 int r;
631 struct cache_disk_superblock *disk_super;
632 struct dm_block *sblock;
633
634 /*
635 * We re-read the superblock every time. Shouldn't need to do this
636 * really.
637 */
638 r = superblock_read_lock(cmd, &sblock);
639 if (r)
640 return r;
641
642 disk_super = dm_block_data(sblock);
643 read_superblock_fields(cmd, disk_super);
644 dm_bm_unlock(sblock);
645
646 return 0;
647 }
648
649 static int __commit_transaction(struct dm_cache_metadata *cmd,
650 flags_mutator mutator)
651 {
652 int r;
653 struct cache_disk_superblock *disk_super;
654 struct dm_block *sblock;
655
656 /*
657 * We need to know if the cache_disk_superblock exceeds a 512-byte sector.
658 */
659 BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
660
661 if (separate_dirty_bits(cmd)) {
662 r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
663 &cmd->dirty_root);
664 if (r)
665 return r;
666 }
667
668 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
669 &cmd->discard_root);
670 if (r)
671 return r;
672
673 r = dm_tm_pre_commit(cmd->tm);
674 if (r < 0)
675 return r;
676
677 r = __save_sm_root(cmd);
678 if (r)
679 return r;
680
681 r = superblock_lock(cmd, &sblock);
682 if (r)
683 return r;
684
685 disk_super = dm_block_data(sblock);
686
687 disk_super->flags = cpu_to_le32(cmd->flags);
688 if (mutator)
689 update_flags(disk_super, mutator);
690
691 disk_super->mapping_root = cpu_to_le64(cmd->root);
692 if (separate_dirty_bits(cmd))
693 disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
694 disk_super->hint_root = cpu_to_le64(cmd->hint_root);
695 disk_super->discard_root = cpu_to_le64(cmd->discard_root);
696 disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
697 disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
698 disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
699 strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
700 disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
701 disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]);
702 disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]);
703
704 disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits);
705 disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
706 disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
707 disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
708 __copy_sm_root(cmd, disk_super);
709
710 return dm_tm_commit(cmd->tm, sblock);
711 }
712
713 /*----------------------------------------------------------------*/
714
715 /*
716 * The mappings are held in a dm-array that has 64-bit values stored in
717 * little-endian format. The index is the cblock, the high 48bits of the
718 * value are the oblock and the low 16 bit the flags.
719 */
720 #define FLAGS_MASK ((1 << 16) - 1)
721
722 static __le64 pack_value(dm_oblock_t block, unsigned flags)
723 {
724 uint64_t value = from_oblock(block);
725 value <<= 16;
726 value = value | (flags & FLAGS_MASK);
727 return cpu_to_le64(value);
728 }
729
730 static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
731 {
732 uint64_t value = le64_to_cpu(value_le);
733 uint64_t b = value >> 16;
734 *block = to_oblock(b);
735 *flags = value & FLAGS_MASK;
736 }
737
738 /*----------------------------------------------------------------*/
739
740 static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
741 sector_t data_block_size,
742 bool may_format_device,
743 size_t policy_hint_size,
744 unsigned metadata_version)
745 {
746 int r;
747 struct dm_cache_metadata *cmd;
748
749 cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
750 if (!cmd) {
751 DMERR("could not allocate metadata struct");
752 return ERR_PTR(-ENOMEM);
753 }
754
755 cmd->version = metadata_version;
756 atomic_set(&cmd->ref_count, 1);
757 init_rwsem(&cmd->root_lock);
758 cmd->bdev = bdev;
759 cmd->data_block_size = data_block_size;
760 cmd->cache_blocks = 0;
761 cmd->policy_hint_size = policy_hint_size;
762 cmd->changed = true;
763 cmd->fail_io = false;
764
765 r = __create_persistent_data_objects(cmd, may_format_device);
766 if (r) {
767 kfree(cmd);
768 return ERR_PTR(r);
769 }
770
771 r = __begin_transaction_flags(cmd, clear_clean_shutdown);
772 if (r < 0) {
773 dm_cache_metadata_close(cmd);
774 return ERR_PTR(r);
775 }
776
777 return cmd;
778 }
779
780 /*
781 * We keep a little list of ref counted metadata objects to prevent two
782 * different target instances creating separate bufio instances. This is
783 * an issue if a table is reloaded before the suspend.
784 */
785 static DEFINE_MUTEX(table_lock);
786 static LIST_HEAD(table);
787
788 static struct dm_cache_metadata *lookup(struct block_device *bdev)
789 {
790 struct dm_cache_metadata *cmd;
791
792 list_for_each_entry(cmd, &table, list)
793 if (cmd->bdev == bdev) {
794 atomic_inc(&cmd->ref_count);
795 return cmd;
796 }
797
798 return NULL;
799 }
800
801 static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
802 sector_t data_block_size,
803 bool may_format_device,
804 size_t policy_hint_size,
805 unsigned metadata_version)
806 {
807 struct dm_cache_metadata *cmd, *cmd2;
808
809 mutex_lock(&table_lock);
810 cmd = lookup(bdev);
811 mutex_unlock(&table_lock);
812
813 if (cmd)
814 return cmd;
815
816 cmd = metadata_open(bdev, data_block_size, may_format_device,
817 policy_hint_size, metadata_version);
818 if (!IS_ERR(cmd)) {
819 mutex_lock(&table_lock);
820 cmd2 = lookup(bdev);
821 if (cmd2) {
822 mutex_unlock(&table_lock);
823 __destroy_persistent_data_objects(cmd);
824 kfree(cmd);
825 return cmd2;
826 }
827 list_add(&cmd->list, &table);
828 mutex_unlock(&table_lock);
829 }
830
831 return cmd;
832 }
833
834 static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
835 {
836 if (cmd->data_block_size != data_block_size) {
837 DMERR("data_block_size (%llu) different from that in metadata (%llu)",
838 (unsigned long long) data_block_size,
839 (unsigned long long) cmd->data_block_size);
840 return false;
841 }
842
843 return true;
844 }
845
846 struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
847 sector_t data_block_size,
848 bool may_format_device,
849 size_t policy_hint_size,
850 unsigned metadata_version)
851 {
852 struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
853 policy_hint_size, metadata_version);
854
855 if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
856 dm_cache_metadata_close(cmd);
857 return ERR_PTR(-EINVAL);
858 }
859
860 return cmd;
861 }
862
863 void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
864 {
865 if (atomic_dec_and_test(&cmd->ref_count)) {
866 mutex_lock(&table_lock);
867 list_del(&cmd->list);
868 mutex_unlock(&table_lock);
869
870 if (!cmd->fail_io)
871 __destroy_persistent_data_objects(cmd);
872 kfree(cmd);
873 }
874 }
875
876 /*
877 * Checks that the given cache block is either unmapped or clean.
878 */
879 static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
880 bool *result)
881 {
882 int r;
883 __le64 value;
884 dm_oblock_t ob;
885 unsigned flags;
886
887 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
888 if (r)
889 return r;
890
891 unpack_value(value, &ob, &flags);
892 *result = !((flags & M_VALID) && (flags & M_DIRTY));
893
894 return 0;
895 }
896
897 static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
898 dm_cblock_t begin, dm_cblock_t end,
899 bool *result)
900 {
901 int r;
902 *result = true;
903
904 while (begin != end) {
905 r = block_clean_combined_dirty(cmd, begin, result);
906 if (r) {
907 DMERR("block_clean_combined_dirty failed");
908 return r;
909 }
910
911 if (!*result) {
912 DMERR("cache block %llu is dirty",
913 (unsigned long long) from_cblock(begin));
914 return 0;
915 }
916
917 begin = to_cblock(from_cblock(begin) + 1);
918 }
919
920 return 0;
921 }
922
923 static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
924 dm_cblock_t begin, dm_cblock_t end,
925 bool *result)
926 {
927 int r;
928 bool dirty_flag;
929 *result = true;
930
931 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
932 from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
933 if (r) {
934 DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__);
935 return r;
936 }
937
938 r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin));
939 if (r) {
940 DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__);
941 dm_bitset_cursor_end(&cmd->dirty_cursor);
942 return r;
943 }
944
945 while (begin != end) {
946 /*
947 * We assume that unmapped blocks have their dirty bit
948 * cleared.
949 */
950 dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor);
951 if (dirty_flag) {
952 DMERR("%s: cache block %llu is dirty", __func__,
953 (unsigned long long) from_cblock(begin));
954 dm_bitset_cursor_end(&cmd->dirty_cursor);
955 *result = false;
956 return 0;
957 }
958
959 begin = to_cblock(from_cblock(begin) + 1);
960 if (begin == end)
961 break;
962
963 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
964 if (r) {
965 DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__);
966 dm_bitset_cursor_end(&cmd->dirty_cursor);
967 return r;
968 }
969 }
970
971 dm_bitset_cursor_end(&cmd->dirty_cursor);
972
973 return 0;
974 }
975
976 static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
977 dm_cblock_t begin, dm_cblock_t end,
978 bool *result)
979 {
980 if (separate_dirty_bits(cmd))
981 return blocks_are_clean_separate_dirty(cmd, begin, end, result);
982 else
983 return blocks_are_clean_combined_dirty(cmd, begin, end, result);
984 }
985
986 static bool cmd_write_lock(struct dm_cache_metadata *cmd)
987 {
988 down_write(&cmd->root_lock);
989 if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) {
990 up_write(&cmd->root_lock);
991 return false;
992 }
993 return true;
994 }
995
996 #define WRITE_LOCK(cmd) \
997 do { \
998 if (!cmd_write_lock((cmd))) \
999 return -EINVAL; \
1000 } while(0)
1001
1002 #define WRITE_LOCK_VOID(cmd) \
1003 do { \
1004 if (!cmd_write_lock((cmd))) \
1005 return; \
1006 } while(0)
1007
1008 #define WRITE_UNLOCK(cmd) \
1009 up_write(&(cmd)->root_lock)
1010
1011 static bool cmd_read_lock(struct dm_cache_metadata *cmd)
1012 {
1013 down_read(&cmd->root_lock);
1014 if (cmd->fail_io) {
1015 up_read(&cmd->root_lock);
1016 return false;
1017 }
1018 return true;
1019 }
1020
1021 #define READ_LOCK(cmd) \
1022 do { \
1023 if (!cmd_read_lock((cmd))) \
1024 return -EINVAL; \
1025 } while(0)
1026
1027 #define READ_LOCK_VOID(cmd) \
1028 do { \
1029 if (!cmd_read_lock((cmd))) \
1030 return; \
1031 } while(0)
1032
1033 #define READ_UNLOCK(cmd) \
1034 up_read(&(cmd)->root_lock)
1035
1036 int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
1037 {
1038 int r;
1039 bool clean;
1040 __le64 null_mapping = pack_value(0, 0);
1041
1042 WRITE_LOCK(cmd);
1043 __dm_bless_for_disk(&null_mapping);
1044
1045 if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) {
1046 r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean);
1047 if (r) {
1048 __dm_unbless_for_disk(&null_mapping);
1049 goto out;
1050 }
1051
1052 if (!clean) {
1053 DMERR("unable to shrink cache due to dirty blocks");
1054 r = -EINVAL;
1055 __dm_unbless_for_disk(&null_mapping);
1056 goto out;
1057 }
1058 }
1059
1060 r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
1061 from_cblock(new_cache_size),
1062 &null_mapping, &cmd->root);
1063 if (r)
1064 goto out;
1065
1066 if (separate_dirty_bits(cmd)) {
1067 r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
1068 from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
1069 false, &cmd->dirty_root);
1070 if (r)
1071 goto out;
1072 }
1073
1074 cmd->cache_blocks = new_cache_size;
1075 cmd->changed = true;
1076
1077 out:
1078 WRITE_UNLOCK(cmd);
1079
1080 return r;
1081 }
1082
1083 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
1084 sector_t discard_block_size,
1085 dm_dblock_t new_nr_entries)
1086 {
1087 int r;
1088
1089 WRITE_LOCK(cmd);
1090 r = dm_bitset_resize(&cmd->discard_info,
1091 cmd->discard_root,
1092 from_dblock(cmd->discard_nr_blocks),
1093 from_dblock(new_nr_entries),
1094 false, &cmd->discard_root);
1095 if (!r) {
1096 cmd->discard_block_size = discard_block_size;
1097 cmd->discard_nr_blocks = new_nr_entries;
1098 }
1099
1100 cmd->changed = true;
1101 WRITE_UNLOCK(cmd);
1102
1103 return r;
1104 }
1105
1106 static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1107 {
1108 return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
1109 from_dblock(b), &cmd->discard_root);
1110 }
1111
1112 static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
1113 {
1114 return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
1115 from_dblock(b), &cmd->discard_root);
1116 }
1117
1118 static int __discard(struct dm_cache_metadata *cmd,
1119 dm_dblock_t dblock, bool discard)
1120 {
1121 int r;
1122
1123 r = (discard ? __set_discard : __clear_discard)(cmd, dblock);
1124 if (r)
1125 return r;
1126
1127 cmd->changed = true;
1128 return 0;
1129 }
1130
1131 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
1132 dm_dblock_t dblock, bool discard)
1133 {
1134 int r;
1135
1136 WRITE_LOCK(cmd);
1137 r = __discard(cmd, dblock, discard);
1138 WRITE_UNLOCK(cmd);
1139
1140 return r;
1141 }
1142
1143 static int __load_discards(struct dm_cache_metadata *cmd,
1144 load_discard_fn fn, void *context)
1145 {
1146 int r = 0;
1147 uint32_t b;
1148 struct dm_bitset_cursor c;
1149
1150 if (from_dblock(cmd->discard_nr_blocks) == 0)
1151 /* nothing to do */
1152 return 0;
1153
1154 if (cmd->clean_when_opened) {
1155 r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root);
1156 if (r)
1157 return r;
1158
1159 r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root,
1160 from_dblock(cmd->discard_nr_blocks), &c);
1161 if (r)
1162 return r;
1163
1164 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1165 r = fn(context, cmd->discard_block_size, to_dblock(b),
1166 dm_bitset_cursor_get_value(&c));
1167 if (r)
1168 break;
1169 }
1170
1171 dm_bitset_cursor_end(&c);
1172
1173 } else {
1174 for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
1175 r = fn(context, cmd->discard_block_size, to_dblock(b), false);
1176 if (r)
1177 return r;
1178 }
1179 }
1180
1181 return r;
1182 }
1183
1184 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
1185 load_discard_fn fn, void *context)
1186 {
1187 int r;
1188
1189 READ_LOCK(cmd);
1190 r = __load_discards(cmd, fn, context);
1191 READ_UNLOCK(cmd);
1192
1193 return r;
1194 }
1195
1196 int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result)
1197 {
1198 READ_LOCK(cmd);
1199 *result = cmd->cache_blocks;
1200 READ_UNLOCK(cmd);
1201
1202 return 0;
1203 }
1204
1205 static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1206 {
1207 int r;
1208 __le64 value = pack_value(0, 0);
1209
1210 __dm_bless_for_disk(&value);
1211 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1212 &value, &cmd->root);
1213 if (r)
1214 return r;
1215
1216 cmd->changed = true;
1217 return 0;
1218 }
1219
1220 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock)
1221 {
1222 int r;
1223
1224 WRITE_LOCK(cmd);
1225 r = __remove(cmd, cblock);
1226 WRITE_UNLOCK(cmd);
1227
1228 return r;
1229 }
1230
1231 static int __insert(struct dm_cache_metadata *cmd,
1232 dm_cblock_t cblock, dm_oblock_t oblock)
1233 {
1234 int r;
1235 __le64 value = pack_value(oblock, M_VALID);
1236 __dm_bless_for_disk(&value);
1237
1238 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1239 &value, &cmd->root);
1240 if (r)
1241 return r;
1242
1243 cmd->changed = true;
1244 return 0;
1245 }
1246
1247 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd,
1248 dm_cblock_t cblock, dm_oblock_t oblock)
1249 {
1250 int r;
1251
1252 WRITE_LOCK(cmd);
1253 r = __insert(cmd, cblock, oblock);
1254 WRITE_UNLOCK(cmd);
1255
1256 return r;
1257 }
1258
1259 struct thunk {
1260 load_mapping_fn fn;
1261 void *context;
1262
1263 struct dm_cache_metadata *cmd;
1264 bool respect_dirty_flags;
1265 bool hints_valid;
1266 };
1267
1268 static bool policy_unchanged(struct dm_cache_metadata *cmd,
1269 struct dm_cache_policy *policy)
1270 {
1271 const char *policy_name = dm_cache_policy_get_name(policy);
1272 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1273 size_t policy_hint_size = dm_cache_policy_get_hint_size(policy);
1274
1275 /*
1276 * Ensure policy names match.
1277 */
1278 if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name)))
1279 return false;
1280
1281 /*
1282 * Ensure policy major versions match.
1283 */
1284 if (cmd->policy_version[0] != policy_version[0])
1285 return false;
1286
1287 /*
1288 * Ensure policy hint sizes match.
1289 */
1290 if (cmd->policy_hint_size != policy_hint_size)
1291 return false;
1292
1293 return true;
1294 }
1295
1296 static bool hints_array_initialized(struct dm_cache_metadata *cmd)
1297 {
1298 return cmd->hint_root && cmd->policy_hint_size;
1299 }
1300
1301 static bool hints_array_available(struct dm_cache_metadata *cmd,
1302 struct dm_cache_policy *policy)
1303 {
1304 return cmd->clean_when_opened && policy_unchanged(cmd, policy) &&
1305 hints_array_initialized(cmd);
1306 }
1307
1308 static int __load_mapping_v1(struct dm_cache_metadata *cmd,
1309 uint64_t cb, bool hints_valid,
1310 struct dm_array_cursor *mapping_cursor,
1311 struct dm_array_cursor *hint_cursor,
1312 load_mapping_fn fn, void *context)
1313 {
1314 int r = 0;
1315
1316 __le64 mapping;
1317 __le32 hint = 0;
1318
1319 __le64 *mapping_value_le;
1320 __le32 *hint_value_le;
1321
1322 dm_oblock_t oblock;
1323 unsigned flags;
1324
1325 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1326 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1327 unpack_value(mapping, &oblock, &flags);
1328
1329 if (flags & M_VALID) {
1330 if (hints_valid) {
1331 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1332 memcpy(&hint, hint_value_le, sizeof(hint));
1333 }
1334
1335 r = fn(context, oblock, to_cblock(cb), flags & M_DIRTY,
1336 le32_to_cpu(hint), hints_valid);
1337 if (r) {
1338 DMERR("policy couldn't load cache block %llu",
1339 (unsigned long long) from_cblock(to_cblock(cb)));
1340 }
1341 }
1342
1343 return r;
1344 }
1345
1346 static int __load_mapping_v2(struct dm_cache_metadata *cmd,
1347 uint64_t cb, bool hints_valid,
1348 struct dm_array_cursor *mapping_cursor,
1349 struct dm_array_cursor *hint_cursor,
1350 struct dm_bitset_cursor *dirty_cursor,
1351 load_mapping_fn fn, void *context)
1352 {
1353 int r = 0;
1354
1355 __le64 mapping;
1356 __le32 hint = 0;
1357
1358 __le64 *mapping_value_le;
1359 __le32 *hint_value_le;
1360
1361 dm_oblock_t oblock;
1362 unsigned flags;
1363 bool dirty;
1364
1365 dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
1366 memcpy(&mapping, mapping_value_le, sizeof(mapping));
1367 unpack_value(mapping, &oblock, &flags);
1368
1369 if (flags & M_VALID) {
1370 if (hints_valid) {
1371 dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
1372 memcpy(&hint, hint_value_le, sizeof(hint));
1373 }
1374
1375 dirty = dm_bitset_cursor_get_value(dirty_cursor);
1376 r = fn(context, oblock, to_cblock(cb), dirty,
1377 le32_to_cpu(hint), hints_valid);
1378 if (r) {
1379 DMERR("policy couldn't load cache block %llu",
1380 (unsigned long long) from_cblock(to_cblock(cb)));
1381 }
1382 }
1383
1384 return r;
1385 }
1386
1387 static int __load_mappings(struct dm_cache_metadata *cmd,
1388 struct dm_cache_policy *policy,
1389 load_mapping_fn fn, void *context)
1390 {
1391 int r;
1392 uint64_t cb;
1393
1394 bool hints_valid = hints_array_available(cmd, policy);
1395
1396 if (from_cblock(cmd->cache_blocks) == 0)
1397 /* Nothing to do */
1398 return 0;
1399
1400 r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);
1401 if (r)
1402 return r;
1403
1404 if (hints_valid) {
1405 r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);
1406 if (r) {
1407 dm_array_cursor_end(&cmd->mapping_cursor);
1408 return r;
1409 }
1410 }
1411
1412 if (separate_dirty_bits(cmd)) {
1413 r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
1414 from_cblock(cmd->cache_blocks),
1415 &cmd->dirty_cursor);
1416 if (r) {
1417 dm_array_cursor_end(&cmd->hint_cursor);
1418 dm_array_cursor_end(&cmd->mapping_cursor);
1419 return r;
1420 }
1421 }
1422
1423 for (cb = 0; ; cb++) {
1424 if (separate_dirty_bits(cmd))
1425 r = __load_mapping_v2(cmd, cb, hints_valid,
1426 &cmd->mapping_cursor,
1427 &cmd->hint_cursor,
1428 &cmd->dirty_cursor,
1429 fn, context);
1430 else
1431 r = __load_mapping_v1(cmd, cb, hints_valid,
1432 &cmd->mapping_cursor, &cmd->hint_cursor,
1433 fn, context);
1434 if (r)
1435 goto out;
1436
1437 /*
1438 * We need to break out before we move the cursors.
1439 */
1440 if (cb >= (from_cblock(cmd->cache_blocks) - 1))
1441 break;
1442
1443 r = dm_array_cursor_next(&cmd->mapping_cursor);
1444 if (r) {
1445 DMERR("dm_array_cursor_next for mapping failed");
1446 goto out;
1447 }
1448
1449 if (hints_valid) {
1450 r = dm_array_cursor_next(&cmd->hint_cursor);
1451 if (r) {
1452 DMERR("dm_array_cursor_next for hint failed");
1453 goto out;
1454 }
1455 }
1456
1457 if (separate_dirty_bits(cmd)) {
1458 r = dm_bitset_cursor_next(&cmd->dirty_cursor);
1459 if (r) {
1460 DMERR("dm_bitset_cursor_next for dirty failed");
1461 goto out;
1462 }
1463 }
1464 }
1465 out:
1466 dm_array_cursor_end(&cmd->mapping_cursor);
1467 if (hints_valid)
1468 dm_array_cursor_end(&cmd->hint_cursor);
1469
1470 if (separate_dirty_bits(cmd))
1471 dm_bitset_cursor_end(&cmd->dirty_cursor);
1472
1473 return r;
1474 }
1475
1476 int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
1477 struct dm_cache_policy *policy,
1478 load_mapping_fn fn, void *context)
1479 {
1480 int r;
1481
1482 READ_LOCK(cmd);
1483 r = __load_mappings(cmd, policy, fn, context);
1484 READ_UNLOCK(cmd);
1485
1486 return r;
1487 }
1488
1489 static int __dump_mapping(void *context, uint64_t cblock, void *leaf)
1490 {
1491 int r = 0;
1492 __le64 value;
1493 dm_oblock_t oblock;
1494 unsigned flags;
1495
1496 memcpy(&value, leaf, sizeof(value));
1497 unpack_value(value, &oblock, &flags);
1498
1499 return r;
1500 }
1501
1502 static int __dump_mappings(struct dm_cache_metadata *cmd)
1503 {
1504 return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL);
1505 }
1506
1507 void dm_cache_dump(struct dm_cache_metadata *cmd)
1508 {
1509 READ_LOCK_VOID(cmd);
1510 __dump_mappings(cmd);
1511 READ_UNLOCK(cmd);
1512 }
1513
1514 int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd)
1515 {
1516 int r;
1517
1518 READ_LOCK(cmd);
1519 r = cmd->changed;
1520 READ_UNLOCK(cmd);
1521
1522 return r;
1523 }
1524
1525 static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty)
1526 {
1527 int r;
1528 unsigned flags;
1529 dm_oblock_t oblock;
1530 __le64 value;
1531
1532 r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value);
1533 if (r)
1534 return r;
1535
1536 unpack_value(value, &oblock, &flags);
1537
1538 if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty))
1539 /* nothing to be done */
1540 return 0;
1541
1542 value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0));
1543 __dm_bless_for_disk(&value);
1544
1545 r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock),
1546 &value, &cmd->root);
1547 if (r)
1548 return r;
1549
1550 cmd->changed = true;
1551 return 0;
1552
1553 }
1554
1555 static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1556 {
1557 int r;
1558 unsigned i;
1559 for (i = 0; i < nr_bits; i++) {
1560 r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
1561 if (r)
1562 return r;
1563 }
1564
1565 return 0;
1566 }
1567
1568 static int is_dirty_callback(uint32_t index, bool *value, void *context)
1569 {
1570 unsigned long *bits = context;
1571 *value = test_bit(index, bits);
1572 return 0;
1573 }
1574
1575 static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
1576 {
1577 int r = 0;
1578
1579 /* nr_bits is really just a sanity check */
1580 if (nr_bits != from_cblock(cmd->cache_blocks)) {
1581 DMERR("dirty bitset is wrong size");
1582 return -EINVAL;
1583 }
1584
1585 r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root);
1586 if (r)
1587 return r;
1588
1589 cmd->changed = true;
1590 return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits);
1591 }
1592
1593 int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
1594 unsigned nr_bits,
1595 unsigned long *bits)
1596 {
1597 int r;
1598
1599 WRITE_LOCK(cmd);
1600 if (separate_dirty_bits(cmd))
1601 r = __set_dirty_bits_v2(cmd, nr_bits, bits);
1602 else
1603 r = __set_dirty_bits_v1(cmd, nr_bits, bits);
1604 WRITE_UNLOCK(cmd);
1605
1606 return r;
1607 }
1608
1609 void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
1610 struct dm_cache_statistics *stats)
1611 {
1612 READ_LOCK_VOID(cmd);
1613 *stats = cmd->stats;
1614 READ_UNLOCK(cmd);
1615 }
1616
1617 void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
1618 struct dm_cache_statistics *stats)
1619 {
1620 WRITE_LOCK_VOID(cmd);
1621 cmd->stats = *stats;
1622 WRITE_UNLOCK(cmd);
1623 }
1624
1625 int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown)
1626 {
1627 int r = -EINVAL;
1628 flags_mutator mutator = (clean_shutdown ? set_clean_shutdown :
1629 clear_clean_shutdown);
1630
1631 WRITE_LOCK(cmd);
1632 if (cmd->fail_io)
1633 goto out;
1634
1635 r = __commit_transaction(cmd, mutator);
1636 if (r)
1637 goto out;
1638
1639 r = __begin_transaction(cmd);
1640 out:
1641 WRITE_UNLOCK(cmd);
1642 return r;
1643 }
1644
1645 int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
1646 dm_block_t *result)
1647 {
1648 int r = -EINVAL;
1649
1650 READ_LOCK(cmd);
1651 if (!cmd->fail_io)
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 if (!cmd->fail_io)
1665 r = dm_sm_get_nr_blocks(cmd->metadata_sm, result);
1666 READ_UNLOCK(cmd);
1667
1668 return r;
1669 }
1670
1671 /*----------------------------------------------------------------*/
1672
1673 static int get_hint(uint32_t index, void *value_le, void *context)
1674 {
1675 uint32_t value;
1676 struct dm_cache_policy *policy = context;
1677
1678 value = policy_get_hint(policy, to_cblock(index));
1679 *((__le32 *) value_le) = cpu_to_le32(value);
1680
1681 return 0;
1682 }
1683
1684 /*
1685 * It's quicker to always delete the hint array, and recreate with
1686 * dm_array_new().
1687 */
1688 static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1689 {
1690 int r;
1691 size_t hint_size;
1692 const char *policy_name = dm_cache_policy_get_name(policy);
1693 const unsigned *policy_version = dm_cache_policy_get_version(policy);
1694
1695 if (!policy_name[0] ||
1696 (strlen(policy_name) > sizeof(cmd->policy_name) - 1))
1697 return -EINVAL;
1698
1699 strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
1700 memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version));
1701
1702 hint_size = dm_cache_policy_get_hint_size(policy);
1703 if (!hint_size)
1704 return 0; /* short-circuit hints initialization */
1705 cmd->policy_hint_size = hint_size;
1706
1707 if (cmd->hint_root) {
1708 r = dm_array_del(&cmd->hint_info, cmd->hint_root);
1709 if (r)
1710 return r;
1711 }
1712
1713 return dm_array_new(&cmd->hint_info, &cmd->hint_root,
1714 from_cblock(cmd->cache_blocks),
1715 get_hint, policy);
1716 }
1717
1718 int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
1719 {
1720 int r;
1721
1722 WRITE_LOCK(cmd);
1723 r = write_hints(cmd, policy);
1724 WRITE_UNLOCK(cmd);
1725
1726 return r;
1727 }
1728
1729 int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result)
1730 {
1731 int r;
1732
1733 READ_LOCK(cmd);
1734 r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result);
1735 READ_UNLOCK(cmd);
1736
1737 return r;
1738 }
1739
1740 void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd)
1741 {
1742 WRITE_LOCK_VOID(cmd);
1743 dm_bm_set_read_only(cmd->bm);
1744 WRITE_UNLOCK(cmd);
1745 }
1746
1747 void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd)
1748 {
1749 WRITE_LOCK_VOID(cmd);
1750 dm_bm_set_read_write(cmd->bm);
1751 WRITE_UNLOCK(cmd);
1752 }
1753
1754 int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd)
1755 {
1756 int r;
1757 struct dm_block *sblock;
1758 struct cache_disk_superblock *disk_super;
1759
1760 WRITE_LOCK(cmd);
1761 set_bit(NEEDS_CHECK, &cmd->flags);
1762
1763 r = superblock_lock(cmd, &sblock);
1764 if (r) {
1765 DMERR("couldn't read superblock");
1766 goto out;
1767 }
1768
1769 disk_super = dm_block_data(sblock);
1770 disk_super->flags = cpu_to_le32(cmd->flags);
1771
1772 dm_bm_unlock(sblock);
1773
1774 out:
1775 WRITE_UNLOCK(cmd);
1776 return r;
1777 }
1778
1779 int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
1780 {
1781 READ_LOCK(cmd);
1782 *result = !!test_bit(NEEDS_CHECK, &cmd->flags);
1783 READ_UNLOCK(cmd);
1784
1785 return 0;
1786 }
1787
1788 int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1789 {
1790 int r;
1791
1792 WRITE_LOCK(cmd);
1793 __destroy_persistent_data_objects(cmd);
1794 r = __create_persistent_data_objects(cmd, false);
1795 if (r)
1796 cmd->fail_io = true;
1797 WRITE_UNLOCK(cmd);
1798
1799 return r;
1800 }
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