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