Commit | Line | Data |
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c6b4fcba JT |
1 | /* |
2 | * Copyright (C) 2012 Red Hat, Inc. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
7 | #include "dm-cache-metadata.h" | |
8 | ||
9 | #include "persistent-data/dm-array.h" | |
10 | #include "persistent-data/dm-bitset.h" | |
11 | #include "persistent-data/dm-space-map.h" | |
12 | #include "persistent-data/dm-space-map-disk.h" | |
13 | #include "persistent-data/dm-transaction-manager.h" | |
14 | ||
15 | #include <linux/device-mapper.h> | |
16 | ||
17 | /*----------------------------------------------------------------*/ | |
18 | ||
19 | #define DM_MSG_PREFIX "cache metadata" | |
20 | ||
21 | #define CACHE_SUPERBLOCK_MAGIC 06142003 | |
22 | #define CACHE_SUPERBLOCK_LOCATION 0 | |
23 | #define CACHE_VERSION 1 | |
24 | #define CACHE_METADATA_CACHE_SIZE 64 | |
25 | ||
26 | /* | |
27 | * 3 for btree insert + | |
28 | * 2 for btree lookup used within space map | |
29 | */ | |
30 | #define CACHE_MAX_CONCURRENT_LOCKS 5 | |
31 | #define SPACE_MAP_ROOT_SIZE 128 | |
32 | ||
33 | enum superblock_flag_bits { | |
34 | /* for spotting crashes that would invalidate the dirty bitset */ | |
35 | CLEAN_SHUTDOWN, | |
36 | }; | |
37 | ||
38 | /* | |
39 | * Each mapping from cache block -> origin block carries a set of flags. | |
40 | */ | |
41 | enum mapping_bits { | |
42 | /* | |
43 | * A valid mapping. Because we're using an array we clear this | |
44 | * flag for an non existant mapping. | |
45 | */ | |
46 | M_VALID = 1, | |
47 | ||
48 | /* | |
49 | * The data on the cache is different from that on the origin. | |
50 | */ | |
51 | M_DIRTY = 2 | |
52 | }; | |
53 | ||
54 | struct cache_disk_superblock { | |
55 | __le32 csum; | |
56 | __le32 flags; | |
57 | __le64 blocknr; | |
58 | ||
59 | __u8 uuid[16]; | |
60 | __le64 magic; | |
61 | __le32 version; | |
62 | ||
63 | __u8 policy_name[CACHE_POLICY_NAME_SIZE]; | |
64 | __le32 policy_hint_size; | |
65 | ||
66 | __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; | |
67 | __le64 mapping_root; | |
68 | __le64 hint_root; | |
69 | ||
70 | __le64 discard_root; | |
71 | __le64 discard_block_size; | |
72 | __le64 discard_nr_blocks; | |
73 | ||
74 | __le32 data_block_size; | |
75 | __le32 metadata_block_size; | |
76 | __le32 cache_blocks; | |
77 | ||
78 | __le32 compat_flags; | |
79 | __le32 compat_ro_flags; | |
80 | __le32 incompat_flags; | |
81 | ||
82 | __le32 read_hits; | |
83 | __le32 read_misses; | |
84 | __le32 write_hits; | |
85 | __le32 write_misses; | |
4e7f506f MS |
86 | |
87 | __le32 policy_version[CACHE_POLICY_VERSION_SIZE]; | |
c6b4fcba JT |
88 | } __packed; |
89 | ||
90 | struct dm_cache_metadata { | |
91 | struct block_device *bdev; | |
92 | struct dm_block_manager *bm; | |
93 | struct dm_space_map *metadata_sm; | |
94 | struct dm_transaction_manager *tm; | |
95 | ||
96 | struct dm_array_info info; | |
97 | struct dm_array_info hint_info; | |
98 | struct dm_disk_bitset discard_info; | |
99 | ||
100 | struct rw_semaphore root_lock; | |
101 | dm_block_t root; | |
102 | dm_block_t hint_root; | |
103 | dm_block_t discard_root; | |
104 | ||
105 | sector_t discard_block_size; | |
106 | dm_dblock_t discard_nr_blocks; | |
107 | ||
108 | sector_t data_block_size; | |
109 | dm_cblock_t cache_blocks; | |
110 | bool changed:1; | |
111 | bool clean_when_opened:1; | |
112 | ||
113 | char policy_name[CACHE_POLICY_NAME_SIZE]; | |
4e7f506f | 114 | unsigned policy_version[CACHE_POLICY_VERSION_SIZE]; |
c6b4fcba JT |
115 | size_t policy_hint_size; |
116 | struct dm_cache_statistics stats; | |
117 | }; | |
118 | ||
119 | /*------------------------------------------------------------------- | |
120 | * superblock validator | |
121 | *-----------------------------------------------------------------*/ | |
122 | ||
123 | #define SUPERBLOCK_CSUM_XOR 9031977 | |
124 | ||
125 | static void sb_prepare_for_write(struct dm_block_validator *v, | |
126 | struct dm_block *b, | |
127 | size_t sb_block_size) | |
128 | { | |
129 | struct cache_disk_superblock *disk_super = dm_block_data(b); | |
130 | ||
131 | disk_super->blocknr = cpu_to_le64(dm_block_location(b)); | |
132 | disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, | |
133 | sb_block_size - sizeof(__le32), | |
134 | SUPERBLOCK_CSUM_XOR)); | |
135 | } | |
136 | ||
137 | static int sb_check(struct dm_block_validator *v, | |
138 | struct dm_block *b, | |
139 | size_t sb_block_size) | |
140 | { | |
141 | struct cache_disk_superblock *disk_super = dm_block_data(b); | |
142 | __le32 csum_le; | |
143 | ||
144 | if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { | |
145 | DMERR("sb_check failed: blocknr %llu: wanted %llu", | |
146 | le64_to_cpu(disk_super->blocknr), | |
147 | (unsigned long long)dm_block_location(b)); | |
148 | return -ENOTBLK; | |
149 | } | |
150 | ||
151 | if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { | |
152 | DMERR("sb_check failed: magic %llu: wanted %llu", | |
153 | le64_to_cpu(disk_super->magic), | |
154 | (unsigned long long)CACHE_SUPERBLOCK_MAGIC); | |
155 | return -EILSEQ; | |
156 | } | |
157 | ||
158 | csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, | |
159 | sb_block_size - sizeof(__le32), | |
160 | SUPERBLOCK_CSUM_XOR)); | |
161 | if (csum_le != disk_super->csum) { | |
162 | DMERR("sb_check failed: csum %u: wanted %u", | |
163 | le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); | |
164 | return -EILSEQ; | |
165 | } | |
166 | ||
167 | return 0; | |
168 | } | |
169 | ||
170 | static struct dm_block_validator sb_validator = { | |
171 | .name = "superblock", | |
172 | .prepare_for_write = sb_prepare_for_write, | |
173 | .check = sb_check | |
174 | }; | |
175 | ||
176 | /*----------------------------------------------------------------*/ | |
177 | ||
178 | static int superblock_read_lock(struct dm_cache_metadata *cmd, | |
179 | struct dm_block **sblock) | |
180 | { | |
181 | return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, | |
182 | &sb_validator, sblock); | |
183 | } | |
184 | ||
185 | static int superblock_lock_zero(struct dm_cache_metadata *cmd, | |
186 | struct dm_block **sblock) | |
187 | { | |
188 | return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, | |
189 | &sb_validator, sblock); | |
190 | } | |
191 | ||
192 | static int superblock_lock(struct dm_cache_metadata *cmd, | |
193 | struct dm_block **sblock) | |
194 | { | |
195 | return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, | |
196 | &sb_validator, sblock); | |
197 | } | |
198 | ||
199 | /*----------------------------------------------------------------*/ | |
200 | ||
dd8b0c20 | 201 | static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result) |
c6b4fcba JT |
202 | { |
203 | int r; | |
204 | unsigned i; | |
205 | struct dm_block *b; | |
206 | __le64 *data_le, zero = cpu_to_le64(0); | |
207 | unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); | |
208 | ||
209 | /* | |
210 | * We can't use a validator here - it may be all zeroes. | |
211 | */ | |
212 | r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); | |
213 | if (r) | |
214 | return r; | |
215 | ||
216 | data_le = dm_block_data(b); | |
dd8b0c20 | 217 | *result = true; |
c6b4fcba JT |
218 | for (i = 0; i < sb_block_size; i++) { |
219 | if (data_le[i] != zero) { | |
dd8b0c20 | 220 | *result = false; |
c6b4fcba JT |
221 | break; |
222 | } | |
223 | } | |
224 | ||
225 | return dm_bm_unlock(b); | |
226 | } | |
227 | ||
228 | static void __setup_mapping_info(struct dm_cache_metadata *cmd) | |
229 | { | |
230 | struct dm_btree_value_type vt; | |
231 | ||
232 | vt.context = NULL; | |
233 | vt.size = sizeof(__le64); | |
234 | vt.inc = NULL; | |
235 | vt.dec = NULL; | |
236 | vt.equal = NULL; | |
237 | dm_array_info_init(&cmd->info, cmd->tm, &vt); | |
238 | ||
239 | if (cmd->policy_hint_size) { | |
240 | vt.size = sizeof(__le32); | |
241 | dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); | |
242 | } | |
243 | } | |
244 | ||
245 | static int __write_initial_superblock(struct dm_cache_metadata *cmd) | |
246 | { | |
247 | int r; | |
248 | struct dm_block *sblock; | |
249 | size_t metadata_len; | |
250 | struct cache_disk_superblock *disk_super; | |
251 | sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT; | |
252 | ||
253 | /* FIXME: see if we can lose the max sectors limit */ | |
254 | if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) | |
255 | bdev_size = DM_CACHE_METADATA_MAX_SECTORS; | |
256 | ||
257 | r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); | |
258 | if (r < 0) | |
259 | return r; | |
260 | ||
261 | r = dm_tm_pre_commit(cmd->tm); | |
262 | if (r < 0) | |
263 | return r; | |
264 | ||
265 | r = superblock_lock_zero(cmd, &sblock); | |
266 | if (r) | |
267 | return r; | |
268 | ||
269 | disk_super = dm_block_data(sblock); | |
270 | disk_super->flags = 0; | |
271 | memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); | |
272 | disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); | |
273 | disk_super->version = cpu_to_le32(CACHE_VERSION); | |
4e7f506f MS |
274 | memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); |
275 | memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); | |
c6b4fcba JT |
276 | disk_super->policy_hint_size = 0; |
277 | ||
278 | r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, | |
279 | metadata_len); | |
280 | if (r < 0) | |
281 | goto bad_locked; | |
282 | ||
283 | disk_super->mapping_root = cpu_to_le64(cmd->root); | |
284 | disk_super->hint_root = cpu_to_le64(cmd->hint_root); | |
285 | disk_super->discard_root = cpu_to_le64(cmd->discard_root); | |
286 | disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); | |
287 | disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); | |
288 | disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); | |
289 | disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); | |
290 | disk_super->cache_blocks = cpu_to_le32(0); | |
c6b4fcba JT |
291 | |
292 | disk_super->read_hits = cpu_to_le32(0); | |
293 | disk_super->read_misses = cpu_to_le32(0); | |
294 | disk_super->write_hits = cpu_to_le32(0); | |
295 | disk_super->write_misses = cpu_to_le32(0); | |
296 | ||
297 | return dm_tm_commit(cmd->tm, sblock); | |
298 | ||
299 | bad_locked: | |
300 | dm_bm_unlock(sblock); | |
301 | return r; | |
302 | } | |
303 | ||
304 | static int __format_metadata(struct dm_cache_metadata *cmd) | |
305 | { | |
306 | int r; | |
307 | ||
308 | r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, | |
309 | &cmd->tm, &cmd->metadata_sm); | |
310 | if (r < 0) { | |
311 | DMERR("tm_create_with_sm failed"); | |
312 | return r; | |
313 | } | |
314 | ||
315 | __setup_mapping_info(cmd); | |
316 | ||
317 | r = dm_array_empty(&cmd->info, &cmd->root); | |
318 | if (r < 0) | |
319 | goto bad; | |
320 | ||
321 | dm_disk_bitset_init(cmd->tm, &cmd->discard_info); | |
322 | ||
323 | r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); | |
324 | if (r < 0) | |
325 | goto bad; | |
326 | ||
327 | cmd->discard_block_size = 0; | |
328 | cmd->discard_nr_blocks = 0; | |
329 | ||
330 | r = __write_initial_superblock(cmd); | |
331 | if (r) | |
332 | goto bad; | |
333 | ||
334 | cmd->clean_when_opened = true; | |
335 | return 0; | |
336 | ||
337 | bad: | |
338 | dm_tm_destroy(cmd->tm); | |
339 | dm_sm_destroy(cmd->metadata_sm); | |
340 | ||
341 | return r; | |
342 | } | |
343 | ||
344 | static int __check_incompat_features(struct cache_disk_superblock *disk_super, | |
345 | struct dm_cache_metadata *cmd) | |
346 | { | |
347 | uint32_t features; | |
348 | ||
349 | features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; | |
350 | if (features) { | |
351 | DMERR("could not access metadata due to unsupported optional features (%lx).", | |
352 | (unsigned long)features); | |
353 | return -EINVAL; | |
354 | } | |
355 | ||
356 | /* | |
357 | * Check for read-only metadata to skip the following RDWR checks. | |
358 | */ | |
359 | if (get_disk_ro(cmd->bdev->bd_disk)) | |
360 | return 0; | |
361 | ||
362 | features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; | |
363 | if (features) { | |
364 | DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", | |
365 | (unsigned long)features); | |
366 | return -EINVAL; | |
367 | } | |
368 | ||
369 | return 0; | |
370 | } | |
371 | ||
372 | static int __open_metadata(struct dm_cache_metadata *cmd) | |
373 | { | |
374 | int r; | |
375 | struct dm_block *sblock; | |
376 | struct cache_disk_superblock *disk_super; | |
377 | unsigned long sb_flags; | |
378 | ||
379 | r = superblock_read_lock(cmd, &sblock); | |
380 | if (r < 0) { | |
381 | DMERR("couldn't read lock superblock"); | |
382 | return r; | |
383 | } | |
384 | ||
385 | disk_super = dm_block_data(sblock); | |
386 | ||
387 | r = __check_incompat_features(disk_super, cmd); | |
388 | if (r < 0) | |
389 | goto bad; | |
390 | ||
391 | r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, | |
392 | disk_super->metadata_space_map_root, | |
393 | sizeof(disk_super->metadata_space_map_root), | |
394 | &cmd->tm, &cmd->metadata_sm); | |
395 | if (r < 0) { | |
396 | DMERR("tm_open_with_sm failed"); | |
397 | goto bad; | |
398 | } | |
399 | ||
400 | __setup_mapping_info(cmd); | |
401 | dm_disk_bitset_init(cmd->tm, &cmd->discard_info); | |
402 | sb_flags = le32_to_cpu(disk_super->flags); | |
403 | cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); | |
404 | return dm_bm_unlock(sblock); | |
405 | ||
406 | bad: | |
407 | dm_bm_unlock(sblock); | |
408 | return r; | |
409 | } | |
410 | ||
411 | static int __open_or_format_metadata(struct dm_cache_metadata *cmd, | |
412 | bool format_device) | |
413 | { | |
dd8b0c20 JT |
414 | int r; |
415 | bool unformatted = false; | |
c6b4fcba JT |
416 | |
417 | r = __superblock_all_zeroes(cmd->bm, &unformatted); | |
418 | if (r) | |
419 | return r; | |
420 | ||
421 | if (unformatted) | |
422 | return format_device ? __format_metadata(cmd) : -EPERM; | |
423 | ||
424 | return __open_metadata(cmd); | |
425 | } | |
426 | ||
427 | static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, | |
428 | bool may_format_device) | |
429 | { | |
430 | int r; | |
431 | cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE, | |
432 | CACHE_METADATA_CACHE_SIZE, | |
433 | CACHE_MAX_CONCURRENT_LOCKS); | |
434 | if (IS_ERR(cmd->bm)) { | |
435 | DMERR("could not create block manager"); | |
436 | return PTR_ERR(cmd->bm); | |
437 | } | |
438 | ||
439 | r = __open_or_format_metadata(cmd, may_format_device); | |
440 | if (r) | |
441 | dm_block_manager_destroy(cmd->bm); | |
442 | ||
443 | return r; | |
444 | } | |
445 | ||
446 | static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) | |
447 | { | |
448 | dm_sm_destroy(cmd->metadata_sm); | |
449 | dm_tm_destroy(cmd->tm); | |
450 | dm_block_manager_destroy(cmd->bm); | |
451 | } | |
452 | ||
453 | typedef unsigned long (*flags_mutator)(unsigned long); | |
454 | ||
455 | static void update_flags(struct cache_disk_superblock *disk_super, | |
456 | flags_mutator mutator) | |
457 | { | |
458 | uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); | |
459 | disk_super->flags = cpu_to_le32(sb_flags); | |
460 | } | |
461 | ||
462 | static unsigned long set_clean_shutdown(unsigned long flags) | |
463 | { | |
464 | set_bit(CLEAN_SHUTDOWN, &flags); | |
465 | return flags; | |
466 | } | |
467 | ||
468 | static unsigned long clear_clean_shutdown(unsigned long flags) | |
469 | { | |
470 | clear_bit(CLEAN_SHUTDOWN, &flags); | |
471 | return flags; | |
472 | } | |
473 | ||
474 | static void read_superblock_fields(struct dm_cache_metadata *cmd, | |
475 | struct cache_disk_superblock *disk_super) | |
476 | { | |
477 | cmd->root = le64_to_cpu(disk_super->mapping_root); | |
478 | cmd->hint_root = le64_to_cpu(disk_super->hint_root); | |
479 | cmd->discard_root = le64_to_cpu(disk_super->discard_root); | |
480 | cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); | |
481 | cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); | |
482 | cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); | |
483 | cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); | |
484 | strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); | |
4e7f506f MS |
485 | cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); |
486 | cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); | |
487 | cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); | |
c6b4fcba JT |
488 | cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); |
489 | ||
490 | cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); | |
491 | cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); | |
492 | cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); | |
493 | cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); | |
494 | ||
495 | cmd->changed = false; | |
496 | } | |
497 | ||
498 | /* | |
499 | * The mutator updates the superblock flags. | |
500 | */ | |
501 | static int __begin_transaction_flags(struct dm_cache_metadata *cmd, | |
502 | flags_mutator mutator) | |
503 | { | |
504 | int r; | |
505 | struct cache_disk_superblock *disk_super; | |
506 | struct dm_block *sblock; | |
507 | ||
508 | r = superblock_lock(cmd, &sblock); | |
509 | if (r) | |
510 | return r; | |
511 | ||
512 | disk_super = dm_block_data(sblock); | |
513 | update_flags(disk_super, mutator); | |
514 | read_superblock_fields(cmd, disk_super); | |
515 | ||
516 | return dm_bm_flush_and_unlock(cmd->bm, sblock); | |
517 | } | |
518 | ||
519 | static int __begin_transaction(struct dm_cache_metadata *cmd) | |
520 | { | |
521 | int r; | |
522 | struct cache_disk_superblock *disk_super; | |
523 | struct dm_block *sblock; | |
524 | ||
525 | /* | |
526 | * We re-read the superblock every time. Shouldn't need to do this | |
527 | * really. | |
528 | */ | |
529 | r = superblock_read_lock(cmd, &sblock); | |
530 | if (r) | |
531 | return r; | |
532 | ||
533 | disk_super = dm_block_data(sblock); | |
534 | read_superblock_fields(cmd, disk_super); | |
535 | dm_bm_unlock(sblock); | |
536 | ||
537 | return 0; | |
538 | } | |
539 | ||
540 | static int __commit_transaction(struct dm_cache_metadata *cmd, | |
541 | flags_mutator mutator) | |
542 | { | |
543 | int r; | |
544 | size_t metadata_len; | |
545 | struct cache_disk_superblock *disk_super; | |
546 | struct dm_block *sblock; | |
547 | ||
548 | /* | |
549 | * We need to know if the cache_disk_superblock exceeds a 512-byte sector. | |
550 | */ | |
551 | BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); | |
552 | ||
553 | r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, | |
554 | &cmd->discard_root); | |
555 | if (r) | |
556 | return r; | |
557 | ||
558 | r = dm_tm_pre_commit(cmd->tm); | |
559 | if (r < 0) | |
560 | return r; | |
561 | ||
562 | r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); | |
563 | if (r < 0) | |
564 | return r; | |
565 | ||
566 | r = superblock_lock(cmd, &sblock); | |
567 | if (r) | |
568 | return r; | |
569 | ||
570 | disk_super = dm_block_data(sblock); | |
571 | ||
572 | if (mutator) | |
573 | update_flags(disk_super, mutator); | |
574 | ||
575 | disk_super->mapping_root = cpu_to_le64(cmd->root); | |
576 | disk_super->hint_root = cpu_to_le64(cmd->hint_root); | |
577 | disk_super->discard_root = cpu_to_le64(cmd->discard_root); | |
578 | disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); | |
579 | disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); | |
580 | disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); | |
581 | strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); | |
4e7f506f MS |
582 | disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); |
583 | disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); | |
584 | disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); | |
c6b4fcba JT |
585 | |
586 | disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); | |
587 | disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); | |
588 | disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); | |
589 | disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); | |
590 | ||
591 | r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root, | |
592 | metadata_len); | |
593 | if (r < 0) { | |
594 | dm_bm_unlock(sblock); | |
595 | return r; | |
596 | } | |
597 | ||
598 | return dm_tm_commit(cmd->tm, sblock); | |
599 | } | |
600 | ||
601 | /*----------------------------------------------------------------*/ | |
602 | ||
603 | /* | |
604 | * The mappings are held in a dm-array that has 64-bit values stored in | |
605 | * little-endian format. The index is the cblock, the high 48bits of the | |
606 | * value are the oblock and the low 16 bit the flags. | |
607 | */ | |
608 | #define FLAGS_MASK ((1 << 16) - 1) | |
609 | ||
610 | static __le64 pack_value(dm_oblock_t block, unsigned flags) | |
611 | { | |
612 | uint64_t value = from_oblock(block); | |
613 | value <<= 16; | |
614 | value = value | (flags & FLAGS_MASK); | |
615 | return cpu_to_le64(value); | |
616 | } | |
617 | ||
618 | static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) | |
619 | { | |
620 | uint64_t value = le64_to_cpu(value_le); | |
621 | uint64_t b = value >> 16; | |
622 | *block = to_oblock(b); | |
623 | *flags = value & FLAGS_MASK; | |
624 | } | |
625 | ||
626 | /*----------------------------------------------------------------*/ | |
627 | ||
628 | struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, | |
629 | sector_t data_block_size, | |
630 | bool may_format_device, | |
631 | size_t policy_hint_size) | |
632 | { | |
633 | int r; | |
634 | struct dm_cache_metadata *cmd; | |
635 | ||
636 | cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); | |
637 | if (!cmd) { | |
638 | DMERR("could not allocate metadata struct"); | |
639 | return NULL; | |
640 | } | |
641 | ||
642 | init_rwsem(&cmd->root_lock); | |
643 | cmd->bdev = bdev; | |
644 | cmd->data_block_size = data_block_size; | |
645 | cmd->cache_blocks = 0; | |
646 | cmd->policy_hint_size = policy_hint_size; | |
647 | cmd->changed = true; | |
648 | ||
649 | r = __create_persistent_data_objects(cmd, may_format_device); | |
650 | if (r) { | |
651 | kfree(cmd); | |
652 | return ERR_PTR(r); | |
653 | } | |
654 | ||
655 | r = __begin_transaction_flags(cmd, clear_clean_shutdown); | |
656 | if (r < 0) { | |
657 | dm_cache_metadata_close(cmd); | |
658 | return ERR_PTR(r); | |
659 | } | |
660 | ||
661 | return cmd; | |
662 | } | |
663 | ||
664 | void dm_cache_metadata_close(struct dm_cache_metadata *cmd) | |
665 | { | |
666 | __destroy_persistent_data_objects(cmd); | |
667 | kfree(cmd); | |
668 | } | |
669 | ||
670 | int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) | |
671 | { | |
672 | int r; | |
673 | __le64 null_mapping = pack_value(0, 0); | |
674 | ||
675 | down_write(&cmd->root_lock); | |
676 | __dm_bless_for_disk(&null_mapping); | |
677 | r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), | |
678 | from_cblock(new_cache_size), | |
679 | &null_mapping, &cmd->root); | |
680 | if (!r) | |
681 | cmd->cache_blocks = new_cache_size; | |
682 | cmd->changed = true; | |
683 | up_write(&cmd->root_lock); | |
684 | ||
685 | return r; | |
686 | } | |
687 | ||
688 | int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, | |
689 | sector_t discard_block_size, | |
690 | dm_dblock_t new_nr_entries) | |
691 | { | |
692 | int r; | |
693 | ||
694 | down_write(&cmd->root_lock); | |
695 | r = dm_bitset_resize(&cmd->discard_info, | |
696 | cmd->discard_root, | |
697 | from_dblock(cmd->discard_nr_blocks), | |
698 | from_dblock(new_nr_entries), | |
699 | false, &cmd->discard_root); | |
700 | if (!r) { | |
701 | cmd->discard_block_size = discard_block_size; | |
702 | cmd->discard_nr_blocks = new_nr_entries; | |
703 | } | |
704 | ||
705 | cmd->changed = true; | |
706 | up_write(&cmd->root_lock); | |
707 | ||
708 | return r; | |
709 | } | |
710 | ||
711 | static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) | |
712 | { | |
713 | return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, | |
714 | from_dblock(b), &cmd->discard_root); | |
715 | } | |
716 | ||
717 | static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) | |
718 | { | |
719 | return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, | |
720 | from_dblock(b), &cmd->discard_root); | |
721 | } | |
722 | ||
723 | static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b, | |
724 | bool *is_discarded) | |
725 | { | |
726 | return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root, | |
727 | from_dblock(b), &cmd->discard_root, | |
728 | is_discarded); | |
729 | } | |
730 | ||
731 | static int __discard(struct dm_cache_metadata *cmd, | |
732 | dm_dblock_t dblock, bool discard) | |
733 | { | |
734 | int r; | |
735 | ||
736 | r = (discard ? __set_discard : __clear_discard)(cmd, dblock); | |
737 | if (r) | |
738 | return r; | |
739 | ||
740 | cmd->changed = true; | |
741 | return 0; | |
742 | } | |
743 | ||
744 | int dm_cache_set_discard(struct dm_cache_metadata *cmd, | |
745 | dm_dblock_t dblock, bool discard) | |
746 | { | |
747 | int r; | |
748 | ||
749 | down_write(&cmd->root_lock); | |
750 | r = __discard(cmd, dblock, discard); | |
751 | up_write(&cmd->root_lock); | |
752 | ||
753 | return r; | |
754 | } | |
755 | ||
756 | static int __load_discards(struct dm_cache_metadata *cmd, | |
757 | load_discard_fn fn, void *context) | |
758 | { | |
759 | int r = 0; | |
760 | dm_block_t b; | |
761 | bool discard; | |
762 | ||
763 | for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { | |
764 | dm_dblock_t dblock = to_dblock(b); | |
765 | ||
766 | if (cmd->clean_when_opened) { | |
767 | r = __is_discarded(cmd, dblock, &discard); | |
768 | if (r) | |
769 | return r; | |
770 | } else | |
771 | discard = false; | |
772 | ||
773 | r = fn(context, cmd->discard_block_size, dblock, discard); | |
774 | if (r) | |
775 | break; | |
776 | } | |
777 | ||
778 | return r; | |
779 | } | |
780 | ||
781 | int dm_cache_load_discards(struct dm_cache_metadata *cmd, | |
782 | load_discard_fn fn, void *context) | |
783 | { | |
784 | int r; | |
785 | ||
786 | down_read(&cmd->root_lock); | |
787 | r = __load_discards(cmd, fn, context); | |
788 | up_read(&cmd->root_lock); | |
789 | ||
790 | return r; | |
791 | } | |
792 | ||
793 | dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd) | |
794 | { | |
795 | dm_cblock_t r; | |
796 | ||
797 | down_read(&cmd->root_lock); | |
798 | r = cmd->cache_blocks; | |
799 | up_read(&cmd->root_lock); | |
800 | ||
801 | return r; | |
802 | } | |
803 | ||
804 | static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) | |
805 | { | |
806 | int r; | |
807 | __le64 value = pack_value(0, 0); | |
808 | ||
809 | __dm_bless_for_disk(&value); | |
810 | r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), | |
811 | &value, &cmd->root); | |
812 | if (r) | |
813 | return r; | |
814 | ||
815 | cmd->changed = true; | |
816 | return 0; | |
817 | } | |
818 | ||
819 | int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) | |
820 | { | |
821 | int r; | |
822 | ||
823 | down_write(&cmd->root_lock); | |
824 | r = __remove(cmd, cblock); | |
825 | up_write(&cmd->root_lock); | |
826 | ||
827 | return r; | |
828 | } | |
829 | ||
830 | static int __insert(struct dm_cache_metadata *cmd, | |
831 | dm_cblock_t cblock, dm_oblock_t oblock) | |
832 | { | |
833 | int r; | |
834 | __le64 value = pack_value(oblock, M_VALID); | |
835 | __dm_bless_for_disk(&value); | |
836 | ||
837 | r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), | |
838 | &value, &cmd->root); | |
839 | if (r) | |
840 | return r; | |
841 | ||
842 | cmd->changed = true; | |
843 | return 0; | |
844 | } | |
845 | ||
846 | int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, | |
847 | dm_cblock_t cblock, dm_oblock_t oblock) | |
848 | { | |
849 | int r; | |
850 | ||
851 | down_write(&cmd->root_lock); | |
852 | r = __insert(cmd, cblock, oblock); | |
853 | up_write(&cmd->root_lock); | |
854 | ||
855 | return r; | |
856 | } | |
857 | ||
858 | struct thunk { | |
859 | load_mapping_fn fn; | |
860 | void *context; | |
861 | ||
862 | struct dm_cache_metadata *cmd; | |
863 | bool respect_dirty_flags; | |
864 | bool hints_valid; | |
865 | }; | |
866 | ||
ea2dd8c1 MS |
867 | static bool policy_unchanged(struct dm_cache_metadata *cmd, |
868 | struct dm_cache_policy *policy) | |
869 | { | |
870 | const char *policy_name = dm_cache_policy_get_name(policy); | |
871 | const unsigned *policy_version = dm_cache_policy_get_version(policy); | |
872 | size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); | |
873 | ||
874 | /* | |
875 | * Ensure policy names match. | |
876 | */ | |
877 | if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) | |
878 | return false; | |
879 | ||
880 | /* | |
881 | * Ensure policy major versions match. | |
882 | */ | |
883 | if (cmd->policy_version[0] != policy_version[0]) | |
884 | return false; | |
885 | ||
886 | /* | |
887 | * Ensure policy hint sizes match. | |
888 | */ | |
889 | if (cmd->policy_hint_size != policy_hint_size) | |
890 | return false; | |
891 | ||
892 | return true; | |
893 | } | |
894 | ||
c6b4fcba JT |
895 | static bool hints_array_initialized(struct dm_cache_metadata *cmd) |
896 | { | |
897 | return cmd->hint_root && cmd->policy_hint_size; | |
898 | } | |
899 | ||
900 | static bool hints_array_available(struct dm_cache_metadata *cmd, | |
ea2dd8c1 | 901 | struct dm_cache_policy *policy) |
c6b4fcba | 902 | { |
ea2dd8c1 | 903 | return cmd->clean_when_opened && policy_unchanged(cmd, policy) && |
c6b4fcba JT |
904 | hints_array_initialized(cmd); |
905 | } | |
906 | ||
907 | static int __load_mapping(void *context, uint64_t cblock, void *leaf) | |
908 | { | |
909 | int r = 0; | |
910 | bool dirty; | |
911 | __le64 value; | |
912 | __le32 hint_value = 0; | |
913 | dm_oblock_t oblock; | |
914 | unsigned flags; | |
915 | struct thunk *thunk = context; | |
916 | struct dm_cache_metadata *cmd = thunk->cmd; | |
917 | ||
918 | memcpy(&value, leaf, sizeof(value)); | |
919 | unpack_value(value, &oblock, &flags); | |
920 | ||
921 | if (flags & M_VALID) { | |
922 | if (thunk->hints_valid) { | |
923 | r = dm_array_get_value(&cmd->hint_info, cmd->hint_root, | |
924 | cblock, &hint_value); | |
925 | if (r && r != -ENODATA) | |
926 | return r; | |
927 | } | |
928 | ||
929 | dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true; | |
930 | r = thunk->fn(thunk->context, oblock, to_cblock(cblock), | |
931 | dirty, le32_to_cpu(hint_value), thunk->hints_valid); | |
932 | } | |
933 | ||
934 | return r; | |
935 | } | |
936 | ||
ea2dd8c1 MS |
937 | static int __load_mappings(struct dm_cache_metadata *cmd, |
938 | struct dm_cache_policy *policy, | |
c6b4fcba JT |
939 | load_mapping_fn fn, void *context) |
940 | { | |
941 | struct thunk thunk; | |
942 | ||
943 | thunk.fn = fn; | |
944 | thunk.context = context; | |
945 | ||
946 | thunk.cmd = cmd; | |
947 | thunk.respect_dirty_flags = cmd->clean_when_opened; | |
ea2dd8c1 | 948 | thunk.hints_valid = hints_array_available(cmd, policy); |
c6b4fcba JT |
949 | |
950 | return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk); | |
951 | } | |
952 | ||
ea2dd8c1 MS |
953 | int dm_cache_load_mappings(struct dm_cache_metadata *cmd, |
954 | struct dm_cache_policy *policy, | |
c6b4fcba JT |
955 | load_mapping_fn fn, void *context) |
956 | { | |
957 | int r; | |
958 | ||
959 | down_read(&cmd->root_lock); | |
ea2dd8c1 | 960 | r = __load_mappings(cmd, policy, fn, context); |
c6b4fcba JT |
961 | up_read(&cmd->root_lock); |
962 | ||
963 | return r; | |
964 | } | |
965 | ||
966 | static int __dump_mapping(void *context, uint64_t cblock, void *leaf) | |
967 | { | |
968 | int r = 0; | |
969 | __le64 value; | |
970 | dm_oblock_t oblock; | |
971 | unsigned flags; | |
972 | ||
973 | memcpy(&value, leaf, sizeof(value)); | |
974 | unpack_value(value, &oblock, &flags); | |
975 | ||
976 | return r; | |
977 | } | |
978 | ||
979 | static int __dump_mappings(struct dm_cache_metadata *cmd) | |
980 | { | |
981 | return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); | |
982 | } | |
983 | ||
984 | void dm_cache_dump(struct dm_cache_metadata *cmd) | |
985 | { | |
986 | down_read(&cmd->root_lock); | |
987 | __dump_mappings(cmd); | |
988 | up_read(&cmd->root_lock); | |
989 | } | |
990 | ||
991 | int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) | |
992 | { | |
993 | int r; | |
994 | ||
995 | down_read(&cmd->root_lock); | |
996 | r = cmd->changed; | |
997 | up_read(&cmd->root_lock); | |
998 | ||
999 | return r; | |
1000 | } | |
1001 | ||
1002 | static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) | |
1003 | { | |
1004 | int r; | |
1005 | unsigned flags; | |
1006 | dm_oblock_t oblock; | |
1007 | __le64 value; | |
1008 | ||
1009 | r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); | |
1010 | if (r) | |
1011 | return r; | |
1012 | ||
1013 | unpack_value(value, &oblock, &flags); | |
1014 | ||
1015 | if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) | |
1016 | /* nothing to be done */ | |
1017 | return 0; | |
1018 | ||
79ed9caf | 1019 | value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); |
c6b4fcba JT |
1020 | __dm_bless_for_disk(&value); |
1021 | ||
1022 | r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), | |
1023 | &value, &cmd->root); | |
1024 | if (r) | |
1025 | return r; | |
1026 | ||
1027 | cmd->changed = true; | |
1028 | return 0; | |
1029 | ||
1030 | } | |
1031 | ||
1032 | int dm_cache_set_dirty(struct dm_cache_metadata *cmd, | |
1033 | dm_cblock_t cblock, bool dirty) | |
1034 | { | |
1035 | int r; | |
1036 | ||
1037 | down_write(&cmd->root_lock); | |
1038 | r = __dirty(cmd, cblock, dirty); | |
1039 | up_write(&cmd->root_lock); | |
1040 | ||
1041 | return r; | |
1042 | } | |
1043 | ||
1044 | void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, | |
1045 | struct dm_cache_statistics *stats) | |
1046 | { | |
1047 | down_read(&cmd->root_lock); | |
8c5008fa | 1048 | *stats = cmd->stats; |
c6b4fcba JT |
1049 | up_read(&cmd->root_lock); |
1050 | } | |
1051 | ||
1052 | void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, | |
1053 | struct dm_cache_statistics *stats) | |
1054 | { | |
1055 | down_write(&cmd->root_lock); | |
8c5008fa | 1056 | cmd->stats = *stats; |
c6b4fcba JT |
1057 | up_write(&cmd->root_lock); |
1058 | } | |
1059 | ||
1060 | int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) | |
1061 | { | |
1062 | int r; | |
1063 | flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : | |
1064 | clear_clean_shutdown); | |
1065 | ||
1066 | down_write(&cmd->root_lock); | |
1067 | r = __commit_transaction(cmd, mutator); | |
1068 | if (r) | |
1069 | goto out; | |
1070 | ||
1071 | r = __begin_transaction(cmd); | |
1072 | ||
1073 | out: | |
1074 | up_write(&cmd->root_lock); | |
1075 | return r; | |
1076 | } | |
1077 | ||
1078 | int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, | |
1079 | dm_block_t *result) | |
1080 | { | |
1081 | int r = -EINVAL; | |
1082 | ||
1083 | down_read(&cmd->root_lock); | |
1084 | r = dm_sm_get_nr_free(cmd->metadata_sm, result); | |
1085 | up_read(&cmd->root_lock); | |
1086 | ||
1087 | return r; | |
1088 | } | |
1089 | ||
1090 | int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, | |
1091 | dm_block_t *result) | |
1092 | { | |
1093 | int r = -EINVAL; | |
1094 | ||
1095 | down_read(&cmd->root_lock); | |
1096 | r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); | |
1097 | up_read(&cmd->root_lock); | |
1098 | ||
1099 | return r; | |
1100 | } | |
1101 | ||
1102 | /*----------------------------------------------------------------*/ | |
1103 | ||
1104 | static int begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) | |
1105 | { | |
1106 | int r; | |
1107 | __le32 value; | |
1108 | size_t hint_size; | |
1109 | const char *policy_name = dm_cache_policy_get_name(policy); | |
4e7f506f | 1110 | const unsigned *policy_version = dm_cache_policy_get_version(policy); |
c6b4fcba JT |
1111 | |
1112 | if (!policy_name[0] || | |
1113 | (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) | |
1114 | return -EINVAL; | |
1115 | ||
ea2dd8c1 | 1116 | if (!policy_unchanged(cmd, policy)) { |
c6b4fcba | 1117 | strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); |
4e7f506f | 1118 | memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); |
c6b4fcba JT |
1119 | |
1120 | hint_size = dm_cache_policy_get_hint_size(policy); | |
1121 | if (!hint_size) | |
1122 | return 0; /* short-circuit hints initialization */ | |
1123 | cmd->policy_hint_size = hint_size; | |
1124 | ||
1125 | if (cmd->hint_root) { | |
1126 | r = dm_array_del(&cmd->hint_info, cmd->hint_root); | |
1127 | if (r) | |
1128 | return r; | |
1129 | } | |
1130 | ||
1131 | r = dm_array_empty(&cmd->hint_info, &cmd->hint_root); | |
1132 | if (r) | |
1133 | return r; | |
1134 | ||
1135 | value = cpu_to_le32(0); | |
1136 | __dm_bless_for_disk(&value); | |
1137 | r = dm_array_resize(&cmd->hint_info, cmd->hint_root, 0, | |
1138 | from_cblock(cmd->cache_blocks), | |
1139 | &value, &cmd->hint_root); | |
1140 | if (r) | |
1141 | return r; | |
1142 | } | |
1143 | ||
1144 | return 0; | |
1145 | } | |
1146 | ||
1147 | int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) | |
1148 | { | |
1149 | int r; | |
1150 | ||
1151 | down_write(&cmd->root_lock); | |
1152 | r = begin_hints(cmd, policy); | |
1153 | up_write(&cmd->root_lock); | |
1154 | ||
1155 | return r; | |
1156 | } | |
1157 | ||
1158 | static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, | |
1159 | uint32_t hint) | |
1160 | { | |
1161 | int r; | |
1162 | __le32 value = cpu_to_le32(hint); | |
1163 | __dm_bless_for_disk(&value); | |
1164 | ||
1165 | r = dm_array_set_value(&cmd->hint_info, cmd->hint_root, | |
1166 | from_cblock(cblock), &value, &cmd->hint_root); | |
1167 | cmd->changed = true; | |
1168 | ||
1169 | return r; | |
1170 | } | |
1171 | ||
1172 | int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock, | |
1173 | uint32_t hint) | |
1174 | { | |
1175 | int r; | |
1176 | ||
1177 | if (!hints_array_initialized(cmd)) | |
1178 | return 0; | |
1179 | ||
1180 | down_write(&cmd->root_lock); | |
1181 | r = save_hint(cmd, cblock, hint); | |
1182 | up_write(&cmd->root_lock); | |
1183 | ||
1184 | return r; | |
1185 | } |