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Commit | Line | Data |
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c6b4fcba JT |
1 | /* |
2 | * Copyright (C) 2012 Red Hat. All rights reserved. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
7 | #include "dm.h" | |
8 | #include "dm-bio-prison.h" | |
b844fe69 | 9 | #include "dm-bio-record.h" |
c6b4fcba JT |
10 | #include "dm-cache-metadata.h" |
11 | ||
12 | #include <linux/dm-io.h> | |
13 | #include <linux/dm-kcopyd.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/mempool.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/slab.h> | |
18 | #include <linux/vmalloc.h> | |
19 | ||
20 | #define DM_MSG_PREFIX "cache" | |
21 | ||
22 | DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle, | |
23 | "A percentage of time allocated for copying to and/or from cache"); | |
24 | ||
25 | /*----------------------------------------------------------------*/ | |
26 | ||
27 | /* | |
28 | * Glossary: | |
29 | * | |
30 | * oblock: index of an origin block | |
31 | * cblock: index of a cache block | |
32 | * promotion: movement of a block from origin to cache | |
33 | * demotion: movement of a block from cache to origin | |
34 | * migration: movement of a block between the origin and cache device, | |
35 | * either direction | |
36 | */ | |
37 | ||
38 | /*----------------------------------------------------------------*/ | |
39 | ||
40 | static size_t bitset_size_in_bytes(unsigned nr_entries) | |
41 | { | |
42 | return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG); | |
43 | } | |
44 | ||
45 | static unsigned long *alloc_bitset(unsigned nr_entries) | |
46 | { | |
47 | size_t s = bitset_size_in_bytes(nr_entries); | |
48 | return vzalloc(s); | |
49 | } | |
50 | ||
51 | static void clear_bitset(void *bitset, unsigned nr_entries) | |
52 | { | |
53 | size_t s = bitset_size_in_bytes(nr_entries); | |
54 | memset(bitset, 0, s); | |
55 | } | |
56 | ||
57 | static void free_bitset(unsigned long *bits) | |
58 | { | |
59 | vfree(bits); | |
60 | } | |
61 | ||
62 | /*----------------------------------------------------------------*/ | |
63 | ||
64 | #define PRISON_CELLS 1024 | |
65 | #define MIGRATION_POOL_SIZE 128 | |
66 | #define COMMIT_PERIOD HZ | |
67 | #define MIGRATION_COUNT_WINDOW 10 | |
68 | ||
69 | /* | |
70 | * The block size of the device holding cache data must be >= 32KB | |
71 | */ | |
72 | #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) | |
73 | ||
74 | /* | |
75 | * FIXME: the cache is read/write for the time being. | |
76 | */ | |
77 | enum cache_mode { | |
78 | CM_WRITE, /* metadata may be changed */ | |
79 | CM_READ_ONLY, /* metadata may not be changed */ | |
80 | }; | |
81 | ||
82 | struct cache_features { | |
83 | enum cache_mode mode; | |
84 | bool write_through:1; | |
85 | }; | |
86 | ||
87 | struct cache_stats { | |
88 | atomic_t read_hit; | |
89 | atomic_t read_miss; | |
90 | atomic_t write_hit; | |
91 | atomic_t write_miss; | |
92 | atomic_t demotion; | |
93 | atomic_t promotion; | |
94 | atomic_t copies_avoided; | |
95 | atomic_t cache_cell_clash; | |
96 | atomic_t commit_count; | |
97 | atomic_t discard_count; | |
98 | }; | |
99 | ||
100 | struct cache { | |
101 | struct dm_target *ti; | |
102 | struct dm_target_callbacks callbacks; | |
103 | ||
104 | /* | |
105 | * Metadata is written to this device. | |
106 | */ | |
107 | struct dm_dev *metadata_dev; | |
108 | ||
109 | /* | |
110 | * The slower of the two data devices. Typically a spindle. | |
111 | */ | |
112 | struct dm_dev *origin_dev; | |
113 | ||
114 | /* | |
115 | * The faster of the two data devices. Typically an SSD. | |
116 | */ | |
117 | struct dm_dev *cache_dev; | |
118 | ||
119 | /* | |
120 | * Cache features such as write-through. | |
121 | */ | |
122 | struct cache_features features; | |
123 | ||
124 | /* | |
125 | * Size of the origin device in _complete_ blocks and native sectors. | |
126 | */ | |
127 | dm_oblock_t origin_blocks; | |
128 | sector_t origin_sectors; | |
129 | ||
130 | /* | |
131 | * Size of the cache device in blocks. | |
132 | */ | |
133 | dm_cblock_t cache_size; | |
134 | ||
135 | /* | |
136 | * Fields for converting from sectors to blocks. | |
137 | */ | |
138 | uint32_t sectors_per_block; | |
139 | int sectors_per_block_shift; | |
140 | ||
141 | struct dm_cache_metadata *cmd; | |
142 | ||
143 | spinlock_t lock; | |
144 | struct bio_list deferred_bios; | |
145 | struct bio_list deferred_flush_bios; | |
e2e74d61 | 146 | struct bio_list deferred_writethrough_bios; |
c6b4fcba JT |
147 | struct list_head quiesced_migrations; |
148 | struct list_head completed_migrations; | |
149 | struct list_head need_commit_migrations; | |
150 | sector_t migration_threshold; | |
151 | atomic_t nr_migrations; | |
152 | wait_queue_head_t migration_wait; | |
153 | ||
154 | /* | |
155 | * cache_size entries, dirty if set | |
156 | */ | |
157 | dm_cblock_t nr_dirty; | |
158 | unsigned long *dirty_bitset; | |
159 | ||
160 | /* | |
161 | * origin_blocks entries, discarded if set. | |
162 | */ | |
414dd67d | 163 | uint32_t discard_block_size; /* a power of 2 times sectors per block */ |
c6b4fcba JT |
164 | dm_dblock_t discard_nr_blocks; |
165 | unsigned long *discard_bitset; | |
166 | ||
167 | struct dm_kcopyd_client *copier; | |
168 | struct workqueue_struct *wq; | |
169 | struct work_struct worker; | |
170 | ||
171 | struct delayed_work waker; | |
172 | unsigned long last_commit_jiffies; | |
173 | ||
174 | struct dm_bio_prison *prison; | |
175 | struct dm_deferred_set *all_io_ds; | |
176 | ||
177 | mempool_t *migration_pool; | |
178 | struct dm_cache_migration *next_migration; | |
179 | ||
180 | struct dm_cache_policy *policy; | |
181 | unsigned policy_nr_args; | |
182 | ||
183 | bool need_tick_bio:1; | |
184 | bool sized:1; | |
185 | bool quiescing:1; | |
186 | bool commit_requested:1; | |
187 | bool loaded_mappings:1; | |
188 | bool loaded_discards:1; | |
189 | ||
190 | struct cache_stats stats; | |
191 | ||
192 | /* | |
193 | * Rather than reconstructing the table line for the status we just | |
194 | * save it and regurgitate. | |
195 | */ | |
196 | unsigned nr_ctr_args; | |
197 | const char **ctr_args; | |
198 | }; | |
199 | ||
200 | struct per_bio_data { | |
201 | bool tick:1; | |
202 | unsigned req_nr:2; | |
203 | struct dm_deferred_entry *all_io_entry; | |
e2e74d61 | 204 | |
19b0092e MS |
205 | /* |
206 | * writethrough fields. These MUST remain at the end of this | |
207 | * structure and the 'cache' member must be the first as it | |
aeed1420 | 208 | * is used to determine the offset of the writethrough fields. |
19b0092e | 209 | */ |
e2e74d61 JT |
210 | struct cache *cache; |
211 | dm_cblock_t cblock; | |
212 | bio_end_io_t *saved_bi_end_io; | |
b844fe69 | 213 | struct dm_bio_details bio_details; |
c6b4fcba JT |
214 | }; |
215 | ||
216 | struct dm_cache_migration { | |
217 | struct list_head list; | |
218 | struct cache *cache; | |
219 | ||
220 | unsigned long start_jiffies; | |
221 | dm_oblock_t old_oblock; | |
222 | dm_oblock_t new_oblock; | |
223 | dm_cblock_t cblock; | |
224 | ||
225 | bool err:1; | |
226 | bool writeback:1; | |
227 | bool demote:1; | |
228 | bool promote:1; | |
229 | ||
230 | struct dm_bio_prison_cell *old_ocell; | |
231 | struct dm_bio_prison_cell *new_ocell; | |
232 | }; | |
233 | ||
234 | /* | |
235 | * Processing a bio in the worker thread may require these memory | |
236 | * allocations. We prealloc to avoid deadlocks (the same worker thread | |
237 | * frees them back to the mempool). | |
238 | */ | |
239 | struct prealloc { | |
240 | struct dm_cache_migration *mg; | |
241 | struct dm_bio_prison_cell *cell1; | |
242 | struct dm_bio_prison_cell *cell2; | |
243 | }; | |
244 | ||
245 | static void wake_worker(struct cache *cache) | |
246 | { | |
247 | queue_work(cache->wq, &cache->worker); | |
248 | } | |
249 | ||
250 | /*----------------------------------------------------------------*/ | |
251 | ||
252 | static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache) | |
253 | { | |
254 | /* FIXME: change to use a local slab. */ | |
255 | return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT); | |
256 | } | |
257 | ||
258 | static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell) | |
259 | { | |
260 | dm_bio_prison_free_cell(cache->prison, cell); | |
261 | } | |
262 | ||
263 | static int prealloc_data_structs(struct cache *cache, struct prealloc *p) | |
264 | { | |
265 | if (!p->mg) { | |
266 | p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT); | |
267 | if (!p->mg) | |
268 | return -ENOMEM; | |
269 | } | |
270 | ||
271 | if (!p->cell1) { | |
272 | p->cell1 = alloc_prison_cell(cache); | |
273 | if (!p->cell1) | |
274 | return -ENOMEM; | |
275 | } | |
276 | ||
277 | if (!p->cell2) { | |
278 | p->cell2 = alloc_prison_cell(cache); | |
279 | if (!p->cell2) | |
280 | return -ENOMEM; | |
281 | } | |
282 | ||
283 | return 0; | |
284 | } | |
285 | ||
286 | static void prealloc_free_structs(struct cache *cache, struct prealloc *p) | |
287 | { | |
288 | if (p->cell2) | |
289 | free_prison_cell(cache, p->cell2); | |
290 | ||
291 | if (p->cell1) | |
292 | free_prison_cell(cache, p->cell1); | |
293 | ||
294 | if (p->mg) | |
295 | mempool_free(p->mg, cache->migration_pool); | |
296 | } | |
297 | ||
298 | static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p) | |
299 | { | |
300 | struct dm_cache_migration *mg = p->mg; | |
301 | ||
302 | BUG_ON(!mg); | |
303 | p->mg = NULL; | |
304 | ||
305 | return mg; | |
306 | } | |
307 | ||
308 | /* | |
309 | * You must have a cell within the prealloc struct to return. If not this | |
310 | * function will BUG() rather than returning NULL. | |
311 | */ | |
312 | static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p) | |
313 | { | |
314 | struct dm_bio_prison_cell *r = NULL; | |
315 | ||
316 | if (p->cell1) { | |
317 | r = p->cell1; | |
318 | p->cell1 = NULL; | |
319 | ||
320 | } else if (p->cell2) { | |
321 | r = p->cell2; | |
322 | p->cell2 = NULL; | |
323 | } else | |
324 | BUG(); | |
325 | ||
326 | return r; | |
327 | } | |
328 | ||
329 | /* | |
330 | * You can't have more than two cells in a prealloc struct. BUG() will be | |
331 | * called if you try and overfill. | |
332 | */ | |
333 | static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell) | |
334 | { | |
335 | if (!p->cell2) | |
336 | p->cell2 = cell; | |
337 | ||
338 | else if (!p->cell1) | |
339 | p->cell1 = cell; | |
340 | ||
341 | else | |
342 | BUG(); | |
343 | } | |
344 | ||
345 | /*----------------------------------------------------------------*/ | |
346 | ||
347 | static void build_key(dm_oblock_t oblock, struct dm_cell_key *key) | |
348 | { | |
349 | key->virtual = 0; | |
350 | key->dev = 0; | |
351 | key->block = from_oblock(oblock); | |
352 | } | |
353 | ||
354 | /* | |
355 | * The caller hands in a preallocated cell, and a free function for it. | |
356 | * The cell will be freed if there's an error, or if it wasn't used because | |
357 | * a cell with that key already exists. | |
358 | */ | |
359 | typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell); | |
360 | ||
361 | static int bio_detain(struct cache *cache, dm_oblock_t oblock, | |
362 | struct bio *bio, struct dm_bio_prison_cell *cell_prealloc, | |
363 | cell_free_fn free_fn, void *free_context, | |
364 | struct dm_bio_prison_cell **cell_result) | |
365 | { | |
366 | int r; | |
367 | struct dm_cell_key key; | |
368 | ||
369 | build_key(oblock, &key); | |
370 | r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result); | |
371 | if (r) | |
372 | free_fn(free_context, cell_prealloc); | |
373 | ||
374 | return r; | |
375 | } | |
376 | ||
377 | static int get_cell(struct cache *cache, | |
378 | dm_oblock_t oblock, | |
379 | struct prealloc *structs, | |
380 | struct dm_bio_prison_cell **cell_result) | |
381 | { | |
382 | int r; | |
383 | struct dm_cell_key key; | |
384 | struct dm_bio_prison_cell *cell_prealloc; | |
385 | ||
386 | cell_prealloc = prealloc_get_cell(structs); | |
387 | ||
388 | build_key(oblock, &key); | |
389 | r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result); | |
390 | if (r) | |
391 | prealloc_put_cell(structs, cell_prealloc); | |
392 | ||
393 | return r; | |
394 | } | |
395 | ||
aeed1420 | 396 | /*----------------------------------------------------------------*/ |
c6b4fcba JT |
397 | |
398 | static bool is_dirty(struct cache *cache, dm_cblock_t b) | |
399 | { | |
400 | return test_bit(from_cblock(b), cache->dirty_bitset); | |
401 | } | |
402 | ||
403 | static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | |
404 | { | |
405 | if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
406 | cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) + 1); | |
407 | policy_set_dirty(cache->policy, oblock); | |
408 | } | |
409 | } | |
410 | ||
411 | static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | |
412 | { | |
413 | if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
414 | policy_clear_dirty(cache->policy, oblock); | |
415 | cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) - 1); | |
416 | if (!from_cblock(cache->nr_dirty)) | |
417 | dm_table_event(cache->ti->table); | |
418 | } | |
419 | } | |
420 | ||
421 | /*----------------------------------------------------------------*/ | |
aeed1420 | 422 | |
c6b4fcba JT |
423 | static bool block_size_is_power_of_two(struct cache *cache) |
424 | { | |
425 | return cache->sectors_per_block_shift >= 0; | |
426 | } | |
427 | ||
43aeaa29 MP |
428 | /* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */ |
429 | #if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6 | |
430 | __always_inline | |
431 | #endif | |
414dd67d JT |
432 | static dm_block_t block_div(dm_block_t b, uint32_t n) |
433 | { | |
434 | do_div(b, n); | |
435 | ||
436 | return b; | |
437 | } | |
438 | ||
c6b4fcba JT |
439 | static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) |
440 | { | |
414dd67d | 441 | uint32_t discard_blocks = cache->discard_block_size; |
c6b4fcba JT |
442 | dm_block_t b = from_oblock(oblock); |
443 | ||
444 | if (!block_size_is_power_of_two(cache)) | |
414dd67d | 445 | discard_blocks = discard_blocks / cache->sectors_per_block; |
c6b4fcba JT |
446 | else |
447 | discard_blocks >>= cache->sectors_per_block_shift; | |
448 | ||
414dd67d | 449 | b = block_div(b, discard_blocks); |
c6b4fcba JT |
450 | |
451 | return to_dblock(b); | |
452 | } | |
453 | ||
454 | static void set_discard(struct cache *cache, dm_dblock_t b) | |
455 | { | |
456 | unsigned long flags; | |
457 | ||
458 | atomic_inc(&cache->stats.discard_count); | |
459 | ||
460 | spin_lock_irqsave(&cache->lock, flags); | |
461 | set_bit(from_dblock(b), cache->discard_bitset); | |
462 | spin_unlock_irqrestore(&cache->lock, flags); | |
463 | } | |
464 | ||
465 | static void clear_discard(struct cache *cache, dm_dblock_t b) | |
466 | { | |
467 | unsigned long flags; | |
468 | ||
469 | spin_lock_irqsave(&cache->lock, flags); | |
470 | clear_bit(from_dblock(b), cache->discard_bitset); | |
471 | spin_unlock_irqrestore(&cache->lock, flags); | |
472 | } | |
473 | ||
474 | static bool is_discarded(struct cache *cache, dm_dblock_t b) | |
475 | { | |
476 | int r; | |
477 | unsigned long flags; | |
478 | ||
479 | spin_lock_irqsave(&cache->lock, flags); | |
480 | r = test_bit(from_dblock(b), cache->discard_bitset); | |
481 | spin_unlock_irqrestore(&cache->lock, flags); | |
482 | ||
483 | return r; | |
484 | } | |
485 | ||
486 | static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) | |
487 | { | |
488 | int r; | |
489 | unsigned long flags; | |
490 | ||
491 | spin_lock_irqsave(&cache->lock, flags); | |
492 | r = test_bit(from_dblock(oblock_to_dblock(cache, b)), | |
493 | cache->discard_bitset); | |
494 | spin_unlock_irqrestore(&cache->lock, flags); | |
495 | ||
496 | return r; | |
497 | } | |
498 | ||
499 | /*----------------------------------------------------------------*/ | |
500 | ||
501 | static void load_stats(struct cache *cache) | |
502 | { | |
503 | struct dm_cache_statistics stats; | |
504 | ||
505 | dm_cache_metadata_get_stats(cache->cmd, &stats); | |
506 | atomic_set(&cache->stats.read_hit, stats.read_hits); | |
507 | atomic_set(&cache->stats.read_miss, stats.read_misses); | |
508 | atomic_set(&cache->stats.write_hit, stats.write_hits); | |
509 | atomic_set(&cache->stats.write_miss, stats.write_misses); | |
510 | } | |
511 | ||
512 | static void save_stats(struct cache *cache) | |
513 | { | |
514 | struct dm_cache_statistics stats; | |
515 | ||
516 | stats.read_hits = atomic_read(&cache->stats.read_hit); | |
517 | stats.read_misses = atomic_read(&cache->stats.read_miss); | |
518 | stats.write_hits = atomic_read(&cache->stats.write_hit); | |
519 | stats.write_misses = atomic_read(&cache->stats.write_miss); | |
520 | ||
521 | dm_cache_metadata_set_stats(cache->cmd, &stats); | |
522 | } | |
523 | ||
524 | /*---------------------------------------------------------------- | |
525 | * Per bio data | |
526 | *--------------------------------------------------------------*/ | |
19b0092e MS |
527 | |
528 | /* | |
529 | * If using writeback, leave out struct per_bio_data's writethrough fields. | |
530 | */ | |
531 | #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) | |
532 | #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) | |
533 | ||
534 | static size_t get_per_bio_data_size(struct cache *cache) | |
535 | { | |
536 | return cache->features.write_through ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; | |
537 | } | |
538 | ||
539 | static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size) | |
c6b4fcba | 540 | { |
19b0092e | 541 | struct per_bio_data *pb = dm_per_bio_data(bio, data_size); |
c6b4fcba JT |
542 | BUG_ON(!pb); |
543 | return pb; | |
544 | } | |
545 | ||
19b0092e | 546 | static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size) |
c6b4fcba | 547 | { |
19b0092e | 548 | struct per_bio_data *pb = get_per_bio_data(bio, data_size); |
c6b4fcba JT |
549 | |
550 | pb->tick = false; | |
551 | pb->req_nr = dm_bio_get_target_bio_nr(bio); | |
552 | pb->all_io_entry = NULL; | |
553 | ||
554 | return pb; | |
555 | } | |
556 | ||
557 | /*---------------------------------------------------------------- | |
558 | * Remapping | |
559 | *--------------------------------------------------------------*/ | |
560 | static void remap_to_origin(struct cache *cache, struct bio *bio) | |
561 | { | |
562 | bio->bi_bdev = cache->origin_dev->bdev; | |
563 | } | |
564 | ||
565 | static void remap_to_cache(struct cache *cache, struct bio *bio, | |
566 | dm_cblock_t cblock) | |
567 | { | |
568 | sector_t bi_sector = bio->bi_sector; | |
569 | ||
570 | bio->bi_bdev = cache->cache_dev->bdev; | |
571 | if (!block_size_is_power_of_two(cache)) | |
572 | bio->bi_sector = (from_cblock(cblock) * cache->sectors_per_block) + | |
573 | sector_div(bi_sector, cache->sectors_per_block); | |
574 | else | |
575 | bio->bi_sector = (from_cblock(cblock) << cache->sectors_per_block_shift) | | |
576 | (bi_sector & (cache->sectors_per_block - 1)); | |
577 | } | |
578 | ||
579 | static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) | |
580 | { | |
581 | unsigned long flags; | |
19b0092e MS |
582 | size_t pb_data_size = get_per_bio_data_size(cache); |
583 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
584 | |
585 | spin_lock_irqsave(&cache->lock, flags); | |
586 | if (cache->need_tick_bio && | |
587 | !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) { | |
588 | pb->tick = true; | |
589 | cache->need_tick_bio = false; | |
590 | } | |
591 | spin_unlock_irqrestore(&cache->lock, flags); | |
592 | } | |
593 | ||
594 | static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, | |
595 | dm_oblock_t oblock) | |
596 | { | |
597 | check_if_tick_bio_needed(cache, bio); | |
598 | remap_to_origin(cache, bio); | |
599 | if (bio_data_dir(bio) == WRITE) | |
600 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | |
601 | } | |
602 | ||
603 | static void remap_to_cache_dirty(struct cache *cache, struct bio *bio, | |
604 | dm_oblock_t oblock, dm_cblock_t cblock) | |
605 | { | |
606 | remap_to_cache(cache, bio, cblock); | |
607 | if (bio_data_dir(bio) == WRITE) { | |
608 | set_dirty(cache, oblock, cblock); | |
609 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | |
610 | } | |
611 | } | |
612 | ||
613 | static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) | |
614 | { | |
615 | sector_t block_nr = bio->bi_sector; | |
616 | ||
617 | if (!block_size_is_power_of_two(cache)) | |
618 | (void) sector_div(block_nr, cache->sectors_per_block); | |
619 | else | |
620 | block_nr >>= cache->sectors_per_block_shift; | |
621 | ||
622 | return to_oblock(block_nr); | |
623 | } | |
624 | ||
625 | static int bio_triggers_commit(struct cache *cache, struct bio *bio) | |
626 | { | |
627 | return bio->bi_rw & (REQ_FLUSH | REQ_FUA); | |
628 | } | |
629 | ||
630 | static void issue(struct cache *cache, struct bio *bio) | |
631 | { | |
632 | unsigned long flags; | |
633 | ||
634 | if (!bio_triggers_commit(cache, bio)) { | |
635 | generic_make_request(bio); | |
636 | return; | |
637 | } | |
638 | ||
639 | /* | |
640 | * Batch together any bios that trigger commits and then issue a | |
641 | * single commit for them in do_worker(). | |
642 | */ | |
643 | spin_lock_irqsave(&cache->lock, flags); | |
644 | cache->commit_requested = true; | |
645 | bio_list_add(&cache->deferred_flush_bios, bio); | |
646 | spin_unlock_irqrestore(&cache->lock, flags); | |
647 | } | |
648 | ||
e2e74d61 JT |
649 | static void defer_writethrough_bio(struct cache *cache, struct bio *bio) |
650 | { | |
651 | unsigned long flags; | |
652 | ||
653 | spin_lock_irqsave(&cache->lock, flags); | |
654 | bio_list_add(&cache->deferred_writethrough_bios, bio); | |
655 | spin_unlock_irqrestore(&cache->lock, flags); | |
656 | ||
657 | wake_worker(cache); | |
658 | } | |
659 | ||
660 | static void writethrough_endio(struct bio *bio, int err) | |
661 | { | |
19b0092e | 662 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
e2e74d61 JT |
663 | bio->bi_end_io = pb->saved_bi_end_io; |
664 | ||
665 | if (err) { | |
666 | bio_endio(bio, err); | |
667 | return; | |
668 | } | |
669 | ||
b844fe69 | 670 | dm_bio_restore(&pb->bio_details, bio); |
e2e74d61 JT |
671 | remap_to_cache(pb->cache, bio, pb->cblock); |
672 | ||
673 | /* | |
674 | * We can't issue this bio directly, since we're in interrupt | |
aeed1420 | 675 | * context. So it gets put on a bio list for processing by the |
e2e74d61 JT |
676 | * worker thread. |
677 | */ | |
678 | defer_writethrough_bio(pb->cache, bio); | |
679 | } | |
680 | ||
681 | /* | |
682 | * When running in writethrough mode we need to send writes to clean blocks | |
683 | * to both the cache and origin devices. In future we'd like to clone the | |
684 | * bio and send them in parallel, but for now we're doing them in | |
685 | * series as this is easier. | |
686 | */ | |
687 | static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, | |
688 | dm_oblock_t oblock, dm_cblock_t cblock) | |
689 | { | |
19b0092e | 690 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
e2e74d61 JT |
691 | |
692 | pb->cache = cache; | |
693 | pb->cblock = cblock; | |
694 | pb->saved_bi_end_io = bio->bi_end_io; | |
b844fe69 | 695 | dm_bio_record(&pb->bio_details, bio); |
e2e74d61 JT |
696 | bio->bi_end_io = writethrough_endio; |
697 | ||
698 | remap_to_origin_clear_discard(pb->cache, bio, oblock); | |
699 | } | |
700 | ||
c6b4fcba JT |
701 | /*---------------------------------------------------------------- |
702 | * Migration processing | |
703 | * | |
704 | * Migration covers moving data from the origin device to the cache, or | |
705 | * vice versa. | |
706 | *--------------------------------------------------------------*/ | |
707 | static void free_migration(struct dm_cache_migration *mg) | |
708 | { | |
709 | mempool_free(mg, mg->cache->migration_pool); | |
710 | } | |
711 | ||
712 | static void inc_nr_migrations(struct cache *cache) | |
713 | { | |
714 | atomic_inc(&cache->nr_migrations); | |
715 | } | |
716 | ||
717 | static void dec_nr_migrations(struct cache *cache) | |
718 | { | |
719 | atomic_dec(&cache->nr_migrations); | |
720 | ||
721 | /* | |
722 | * Wake the worker in case we're suspending the target. | |
723 | */ | |
724 | wake_up(&cache->migration_wait); | |
725 | } | |
726 | ||
727 | static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | |
728 | bool holder) | |
729 | { | |
730 | (holder ? dm_cell_release : dm_cell_release_no_holder) | |
731 | (cache->prison, cell, &cache->deferred_bios); | |
732 | free_prison_cell(cache, cell); | |
733 | } | |
734 | ||
735 | static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | |
736 | bool holder) | |
737 | { | |
738 | unsigned long flags; | |
739 | ||
740 | spin_lock_irqsave(&cache->lock, flags); | |
741 | __cell_defer(cache, cell, holder); | |
742 | spin_unlock_irqrestore(&cache->lock, flags); | |
743 | ||
744 | wake_worker(cache); | |
745 | } | |
746 | ||
747 | static void cleanup_migration(struct dm_cache_migration *mg) | |
748 | { | |
749 | dec_nr_migrations(mg->cache); | |
750 | free_migration(mg); | |
751 | } | |
752 | ||
753 | static void migration_failure(struct dm_cache_migration *mg) | |
754 | { | |
755 | struct cache *cache = mg->cache; | |
756 | ||
757 | if (mg->writeback) { | |
758 | DMWARN_LIMIT("writeback failed; couldn't copy block"); | |
759 | set_dirty(cache, mg->old_oblock, mg->cblock); | |
760 | cell_defer(cache, mg->old_ocell, false); | |
761 | ||
762 | } else if (mg->demote) { | |
763 | DMWARN_LIMIT("demotion failed; couldn't copy block"); | |
764 | policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); | |
765 | ||
766 | cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1); | |
767 | if (mg->promote) | |
768 | cell_defer(cache, mg->new_ocell, 1); | |
769 | } else { | |
770 | DMWARN_LIMIT("promotion failed; couldn't copy block"); | |
771 | policy_remove_mapping(cache->policy, mg->new_oblock); | |
772 | cell_defer(cache, mg->new_ocell, 1); | |
773 | } | |
774 | ||
775 | cleanup_migration(mg); | |
776 | } | |
777 | ||
778 | static void migration_success_pre_commit(struct dm_cache_migration *mg) | |
779 | { | |
780 | unsigned long flags; | |
781 | struct cache *cache = mg->cache; | |
782 | ||
783 | if (mg->writeback) { | |
784 | cell_defer(cache, mg->old_ocell, false); | |
785 | clear_dirty(cache, mg->old_oblock, mg->cblock); | |
786 | cleanup_migration(mg); | |
787 | return; | |
788 | ||
789 | } else if (mg->demote) { | |
790 | if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) { | |
791 | DMWARN_LIMIT("demotion failed; couldn't update on disk metadata"); | |
792 | policy_force_mapping(cache->policy, mg->new_oblock, | |
793 | mg->old_oblock); | |
794 | if (mg->promote) | |
795 | cell_defer(cache, mg->new_ocell, true); | |
796 | cleanup_migration(mg); | |
797 | return; | |
798 | } | |
799 | } else { | |
800 | if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) { | |
801 | DMWARN_LIMIT("promotion failed; couldn't update on disk metadata"); | |
802 | policy_remove_mapping(cache->policy, mg->new_oblock); | |
803 | cleanup_migration(mg); | |
804 | return; | |
805 | } | |
806 | } | |
807 | ||
808 | spin_lock_irqsave(&cache->lock, flags); | |
809 | list_add_tail(&mg->list, &cache->need_commit_migrations); | |
810 | cache->commit_requested = true; | |
811 | spin_unlock_irqrestore(&cache->lock, flags); | |
812 | } | |
813 | ||
814 | static void migration_success_post_commit(struct dm_cache_migration *mg) | |
815 | { | |
816 | unsigned long flags; | |
817 | struct cache *cache = mg->cache; | |
818 | ||
819 | if (mg->writeback) { | |
820 | DMWARN("writeback unexpectedly triggered commit"); | |
821 | return; | |
822 | ||
823 | } else if (mg->demote) { | |
824 | cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1); | |
825 | ||
826 | if (mg->promote) { | |
827 | mg->demote = false; | |
828 | ||
829 | spin_lock_irqsave(&cache->lock, flags); | |
830 | list_add_tail(&mg->list, &cache->quiesced_migrations); | |
831 | spin_unlock_irqrestore(&cache->lock, flags); | |
832 | ||
833 | } else | |
834 | cleanup_migration(mg); | |
835 | ||
836 | } else { | |
837 | cell_defer(cache, mg->new_ocell, true); | |
838 | clear_dirty(cache, mg->new_oblock, mg->cblock); | |
839 | cleanup_migration(mg); | |
840 | } | |
841 | } | |
842 | ||
843 | static void copy_complete(int read_err, unsigned long write_err, void *context) | |
844 | { | |
845 | unsigned long flags; | |
846 | struct dm_cache_migration *mg = (struct dm_cache_migration *) context; | |
847 | struct cache *cache = mg->cache; | |
848 | ||
849 | if (read_err || write_err) | |
850 | mg->err = true; | |
851 | ||
852 | spin_lock_irqsave(&cache->lock, flags); | |
853 | list_add_tail(&mg->list, &cache->completed_migrations); | |
854 | spin_unlock_irqrestore(&cache->lock, flags); | |
855 | ||
856 | wake_worker(cache); | |
857 | } | |
858 | ||
859 | static void issue_copy_real(struct dm_cache_migration *mg) | |
860 | { | |
861 | int r; | |
862 | struct dm_io_region o_region, c_region; | |
863 | struct cache *cache = mg->cache; | |
864 | ||
865 | o_region.bdev = cache->origin_dev->bdev; | |
866 | o_region.count = cache->sectors_per_block; | |
867 | ||
868 | c_region.bdev = cache->cache_dev->bdev; | |
869 | c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block; | |
870 | c_region.count = cache->sectors_per_block; | |
871 | ||
872 | if (mg->writeback || mg->demote) { | |
873 | /* demote */ | |
874 | o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block; | |
875 | r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg); | |
876 | } else { | |
877 | /* promote */ | |
878 | o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block; | |
879 | r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg); | |
880 | } | |
881 | ||
882 | if (r < 0) | |
883 | migration_failure(mg); | |
884 | } | |
885 | ||
886 | static void avoid_copy(struct dm_cache_migration *mg) | |
887 | { | |
888 | atomic_inc(&mg->cache->stats.copies_avoided); | |
889 | migration_success_pre_commit(mg); | |
890 | } | |
891 | ||
892 | static void issue_copy(struct dm_cache_migration *mg) | |
893 | { | |
894 | bool avoid; | |
895 | struct cache *cache = mg->cache; | |
896 | ||
897 | if (mg->writeback || mg->demote) | |
898 | avoid = !is_dirty(cache, mg->cblock) || | |
899 | is_discarded_oblock(cache, mg->old_oblock); | |
900 | else | |
901 | avoid = is_discarded_oblock(cache, mg->new_oblock); | |
902 | ||
903 | avoid ? avoid_copy(mg) : issue_copy_real(mg); | |
904 | } | |
905 | ||
906 | static void complete_migration(struct dm_cache_migration *mg) | |
907 | { | |
908 | if (mg->err) | |
909 | migration_failure(mg); | |
910 | else | |
911 | migration_success_pre_commit(mg); | |
912 | } | |
913 | ||
914 | static void process_migrations(struct cache *cache, struct list_head *head, | |
915 | void (*fn)(struct dm_cache_migration *)) | |
916 | { | |
917 | unsigned long flags; | |
918 | struct list_head list; | |
919 | struct dm_cache_migration *mg, *tmp; | |
920 | ||
921 | INIT_LIST_HEAD(&list); | |
922 | spin_lock_irqsave(&cache->lock, flags); | |
923 | list_splice_init(head, &list); | |
924 | spin_unlock_irqrestore(&cache->lock, flags); | |
925 | ||
926 | list_for_each_entry_safe(mg, tmp, &list, list) | |
927 | fn(mg); | |
928 | } | |
929 | ||
930 | static void __queue_quiesced_migration(struct dm_cache_migration *mg) | |
931 | { | |
932 | list_add_tail(&mg->list, &mg->cache->quiesced_migrations); | |
933 | } | |
934 | ||
935 | static void queue_quiesced_migration(struct dm_cache_migration *mg) | |
936 | { | |
937 | unsigned long flags; | |
938 | struct cache *cache = mg->cache; | |
939 | ||
940 | spin_lock_irqsave(&cache->lock, flags); | |
941 | __queue_quiesced_migration(mg); | |
942 | spin_unlock_irqrestore(&cache->lock, flags); | |
943 | ||
944 | wake_worker(cache); | |
945 | } | |
946 | ||
947 | static void queue_quiesced_migrations(struct cache *cache, struct list_head *work) | |
948 | { | |
949 | unsigned long flags; | |
950 | struct dm_cache_migration *mg, *tmp; | |
951 | ||
952 | spin_lock_irqsave(&cache->lock, flags); | |
953 | list_for_each_entry_safe(mg, tmp, work, list) | |
954 | __queue_quiesced_migration(mg); | |
955 | spin_unlock_irqrestore(&cache->lock, flags); | |
956 | ||
957 | wake_worker(cache); | |
958 | } | |
959 | ||
960 | static void check_for_quiesced_migrations(struct cache *cache, | |
961 | struct per_bio_data *pb) | |
962 | { | |
963 | struct list_head work; | |
964 | ||
965 | if (!pb->all_io_entry) | |
966 | return; | |
967 | ||
968 | INIT_LIST_HEAD(&work); | |
969 | if (pb->all_io_entry) | |
970 | dm_deferred_entry_dec(pb->all_io_entry, &work); | |
971 | ||
972 | if (!list_empty(&work)) | |
973 | queue_quiesced_migrations(cache, &work); | |
974 | } | |
975 | ||
976 | static void quiesce_migration(struct dm_cache_migration *mg) | |
977 | { | |
978 | if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list)) | |
979 | queue_quiesced_migration(mg); | |
980 | } | |
981 | ||
982 | static void promote(struct cache *cache, struct prealloc *structs, | |
983 | dm_oblock_t oblock, dm_cblock_t cblock, | |
984 | struct dm_bio_prison_cell *cell) | |
985 | { | |
986 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
987 | ||
988 | mg->err = false; | |
989 | mg->writeback = false; | |
990 | mg->demote = false; | |
991 | mg->promote = true; | |
992 | mg->cache = cache; | |
993 | mg->new_oblock = oblock; | |
994 | mg->cblock = cblock; | |
995 | mg->old_ocell = NULL; | |
996 | mg->new_ocell = cell; | |
997 | mg->start_jiffies = jiffies; | |
998 | ||
999 | inc_nr_migrations(cache); | |
1000 | quiesce_migration(mg); | |
1001 | } | |
1002 | ||
1003 | static void writeback(struct cache *cache, struct prealloc *structs, | |
1004 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1005 | struct dm_bio_prison_cell *cell) | |
1006 | { | |
1007 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1008 | ||
1009 | mg->err = false; | |
1010 | mg->writeback = true; | |
1011 | mg->demote = false; | |
1012 | mg->promote = false; | |
1013 | mg->cache = cache; | |
1014 | mg->old_oblock = oblock; | |
1015 | mg->cblock = cblock; | |
1016 | mg->old_ocell = cell; | |
1017 | mg->new_ocell = NULL; | |
1018 | mg->start_jiffies = jiffies; | |
1019 | ||
1020 | inc_nr_migrations(cache); | |
1021 | quiesce_migration(mg); | |
1022 | } | |
1023 | ||
1024 | static void demote_then_promote(struct cache *cache, struct prealloc *structs, | |
1025 | dm_oblock_t old_oblock, dm_oblock_t new_oblock, | |
1026 | dm_cblock_t cblock, | |
1027 | struct dm_bio_prison_cell *old_ocell, | |
1028 | struct dm_bio_prison_cell *new_ocell) | |
1029 | { | |
1030 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1031 | ||
1032 | mg->err = false; | |
1033 | mg->writeback = false; | |
1034 | mg->demote = true; | |
1035 | mg->promote = true; | |
1036 | mg->cache = cache; | |
1037 | mg->old_oblock = old_oblock; | |
1038 | mg->new_oblock = new_oblock; | |
1039 | mg->cblock = cblock; | |
1040 | mg->old_ocell = old_ocell; | |
1041 | mg->new_ocell = new_ocell; | |
1042 | mg->start_jiffies = jiffies; | |
1043 | ||
1044 | inc_nr_migrations(cache); | |
1045 | quiesce_migration(mg); | |
1046 | } | |
1047 | ||
1048 | /*---------------------------------------------------------------- | |
1049 | * bio processing | |
1050 | *--------------------------------------------------------------*/ | |
1051 | static void defer_bio(struct cache *cache, struct bio *bio) | |
1052 | { | |
1053 | unsigned long flags; | |
1054 | ||
1055 | spin_lock_irqsave(&cache->lock, flags); | |
1056 | bio_list_add(&cache->deferred_bios, bio); | |
1057 | spin_unlock_irqrestore(&cache->lock, flags); | |
1058 | ||
1059 | wake_worker(cache); | |
1060 | } | |
1061 | ||
1062 | static void process_flush_bio(struct cache *cache, struct bio *bio) | |
1063 | { | |
19b0092e MS |
1064 | size_t pb_data_size = get_per_bio_data_size(cache); |
1065 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
1066 | |
1067 | BUG_ON(bio->bi_size); | |
1068 | if (!pb->req_nr) | |
1069 | remap_to_origin(cache, bio); | |
1070 | else | |
1071 | remap_to_cache(cache, bio, 0); | |
1072 | ||
1073 | issue(cache, bio); | |
1074 | } | |
1075 | ||
1076 | /* | |
1077 | * People generally discard large parts of a device, eg, the whole device | |
1078 | * when formatting. Splitting these large discards up into cache block | |
1079 | * sized ios and then quiescing (always neccessary for discard) takes too | |
1080 | * long. | |
1081 | * | |
1082 | * We keep it simple, and allow any size of discard to come in, and just | |
1083 | * mark off blocks on the discard bitset. No passdown occurs! | |
1084 | * | |
1085 | * To implement passdown we need to change the bio_prison such that a cell | |
1086 | * can have a key that spans many blocks. | |
1087 | */ | |
1088 | static void process_discard_bio(struct cache *cache, struct bio *bio) | |
1089 | { | |
1090 | dm_block_t start_block = dm_sector_div_up(bio->bi_sector, | |
1091 | cache->discard_block_size); | |
1092 | dm_block_t end_block = bio->bi_sector + bio_sectors(bio); | |
1093 | dm_block_t b; | |
1094 | ||
414dd67d | 1095 | end_block = block_div(end_block, cache->discard_block_size); |
c6b4fcba JT |
1096 | |
1097 | for (b = start_block; b < end_block; b++) | |
1098 | set_discard(cache, to_dblock(b)); | |
1099 | ||
1100 | bio_endio(bio, 0); | |
1101 | } | |
1102 | ||
1103 | static bool spare_migration_bandwidth(struct cache *cache) | |
1104 | { | |
1105 | sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) * | |
1106 | cache->sectors_per_block; | |
1107 | return current_volume < cache->migration_threshold; | |
1108 | } | |
1109 | ||
1110 | static bool is_writethrough_io(struct cache *cache, struct bio *bio, | |
1111 | dm_cblock_t cblock) | |
1112 | { | |
1113 | return bio_data_dir(bio) == WRITE && | |
1114 | cache->features.write_through && !is_dirty(cache, cblock); | |
1115 | } | |
1116 | ||
1117 | static void inc_hit_counter(struct cache *cache, struct bio *bio) | |
1118 | { | |
1119 | atomic_inc(bio_data_dir(bio) == READ ? | |
1120 | &cache->stats.read_hit : &cache->stats.write_hit); | |
1121 | } | |
1122 | ||
1123 | static void inc_miss_counter(struct cache *cache, struct bio *bio) | |
1124 | { | |
1125 | atomic_inc(bio_data_dir(bio) == READ ? | |
1126 | &cache->stats.read_miss : &cache->stats.write_miss); | |
1127 | } | |
1128 | ||
1129 | static void process_bio(struct cache *cache, struct prealloc *structs, | |
1130 | struct bio *bio) | |
1131 | { | |
1132 | int r; | |
1133 | bool release_cell = true; | |
1134 | dm_oblock_t block = get_bio_block(cache, bio); | |
1135 | struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell; | |
1136 | struct policy_result lookup_result; | |
19b0092e MS |
1137 | size_t pb_data_size = get_per_bio_data_size(cache); |
1138 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
1139 | bool discarded_block = is_discarded_oblock(cache, block); |
1140 | bool can_migrate = discarded_block || spare_migration_bandwidth(cache); | |
1141 | ||
1142 | /* | |
1143 | * Check to see if that block is currently migrating. | |
1144 | */ | |
1145 | cell_prealloc = prealloc_get_cell(structs); | |
1146 | r = bio_detain(cache, block, bio, cell_prealloc, | |
1147 | (cell_free_fn) prealloc_put_cell, | |
1148 | structs, &new_ocell); | |
1149 | if (r > 0) | |
1150 | return; | |
1151 | ||
1152 | r = policy_map(cache->policy, block, true, can_migrate, discarded_block, | |
1153 | bio, &lookup_result); | |
1154 | ||
1155 | if (r == -EWOULDBLOCK) | |
1156 | /* migration has been denied */ | |
1157 | lookup_result.op = POLICY_MISS; | |
1158 | ||
1159 | switch (lookup_result.op) { | |
1160 | case POLICY_HIT: | |
1161 | inc_hit_counter(cache, bio); | |
1162 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
1163 | ||
e2e74d61 JT |
1164 | if (is_writethrough_io(cache, bio, lookup_result.cblock)) |
1165 | remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); | |
1166 | else | |
c6b4fcba JT |
1167 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); |
1168 | ||
1169 | issue(cache, bio); | |
1170 | break; | |
1171 | ||
1172 | case POLICY_MISS: | |
1173 | inc_miss_counter(cache, bio); | |
1174 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
e2e74d61 JT |
1175 | remap_to_origin_clear_discard(cache, bio, block); |
1176 | issue(cache, bio); | |
c6b4fcba JT |
1177 | break; |
1178 | ||
1179 | case POLICY_NEW: | |
1180 | atomic_inc(&cache->stats.promotion); | |
1181 | promote(cache, structs, block, lookup_result.cblock, new_ocell); | |
1182 | release_cell = false; | |
1183 | break; | |
1184 | ||
1185 | case POLICY_REPLACE: | |
1186 | cell_prealloc = prealloc_get_cell(structs); | |
1187 | r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc, | |
1188 | (cell_free_fn) prealloc_put_cell, | |
1189 | structs, &old_ocell); | |
1190 | if (r > 0) { | |
1191 | /* | |
1192 | * We have to be careful to avoid lock inversion of | |
1193 | * the cells. So we back off, and wait for the | |
1194 | * old_ocell to become free. | |
1195 | */ | |
1196 | policy_force_mapping(cache->policy, block, | |
1197 | lookup_result.old_oblock); | |
1198 | atomic_inc(&cache->stats.cache_cell_clash); | |
1199 | break; | |
1200 | } | |
1201 | atomic_inc(&cache->stats.demotion); | |
1202 | atomic_inc(&cache->stats.promotion); | |
1203 | ||
1204 | demote_then_promote(cache, structs, lookup_result.old_oblock, | |
1205 | block, lookup_result.cblock, | |
1206 | old_ocell, new_ocell); | |
1207 | release_cell = false; | |
1208 | break; | |
1209 | ||
1210 | default: | |
1211 | DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__, | |
1212 | (unsigned) lookup_result.op); | |
1213 | bio_io_error(bio); | |
1214 | } | |
1215 | ||
1216 | if (release_cell) | |
1217 | cell_defer(cache, new_ocell, false); | |
1218 | } | |
1219 | ||
1220 | static int need_commit_due_to_time(struct cache *cache) | |
1221 | { | |
1222 | return jiffies < cache->last_commit_jiffies || | |
1223 | jiffies > cache->last_commit_jiffies + COMMIT_PERIOD; | |
1224 | } | |
1225 | ||
1226 | static int commit_if_needed(struct cache *cache) | |
1227 | { | |
1228 | if (dm_cache_changed_this_transaction(cache->cmd) && | |
1229 | (cache->commit_requested || need_commit_due_to_time(cache))) { | |
1230 | atomic_inc(&cache->stats.commit_count); | |
1231 | cache->last_commit_jiffies = jiffies; | |
1232 | cache->commit_requested = false; | |
1233 | return dm_cache_commit(cache->cmd, false); | |
1234 | } | |
1235 | ||
1236 | return 0; | |
1237 | } | |
1238 | ||
1239 | static void process_deferred_bios(struct cache *cache) | |
1240 | { | |
1241 | unsigned long flags; | |
1242 | struct bio_list bios; | |
1243 | struct bio *bio; | |
1244 | struct prealloc structs; | |
1245 | ||
1246 | memset(&structs, 0, sizeof(structs)); | |
1247 | bio_list_init(&bios); | |
1248 | ||
1249 | spin_lock_irqsave(&cache->lock, flags); | |
1250 | bio_list_merge(&bios, &cache->deferred_bios); | |
1251 | bio_list_init(&cache->deferred_bios); | |
1252 | spin_unlock_irqrestore(&cache->lock, flags); | |
1253 | ||
1254 | while (!bio_list_empty(&bios)) { | |
1255 | /* | |
1256 | * If we've got no free migration structs, and processing | |
1257 | * this bio might require one, we pause until there are some | |
1258 | * prepared mappings to process. | |
1259 | */ | |
1260 | if (prealloc_data_structs(cache, &structs)) { | |
1261 | spin_lock_irqsave(&cache->lock, flags); | |
1262 | bio_list_merge(&cache->deferred_bios, &bios); | |
1263 | spin_unlock_irqrestore(&cache->lock, flags); | |
1264 | break; | |
1265 | } | |
1266 | ||
1267 | bio = bio_list_pop(&bios); | |
1268 | ||
1269 | if (bio->bi_rw & REQ_FLUSH) | |
1270 | process_flush_bio(cache, bio); | |
1271 | else if (bio->bi_rw & REQ_DISCARD) | |
1272 | process_discard_bio(cache, bio); | |
1273 | else | |
1274 | process_bio(cache, &structs, bio); | |
1275 | } | |
1276 | ||
1277 | prealloc_free_structs(cache, &structs); | |
1278 | } | |
1279 | ||
1280 | static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) | |
1281 | { | |
1282 | unsigned long flags; | |
1283 | struct bio_list bios; | |
1284 | struct bio *bio; | |
1285 | ||
1286 | bio_list_init(&bios); | |
1287 | ||
1288 | spin_lock_irqsave(&cache->lock, flags); | |
1289 | bio_list_merge(&bios, &cache->deferred_flush_bios); | |
1290 | bio_list_init(&cache->deferred_flush_bios); | |
1291 | spin_unlock_irqrestore(&cache->lock, flags); | |
1292 | ||
1293 | while ((bio = bio_list_pop(&bios))) | |
1294 | submit_bios ? generic_make_request(bio) : bio_io_error(bio); | |
1295 | } | |
1296 | ||
e2e74d61 JT |
1297 | static void process_deferred_writethrough_bios(struct cache *cache) |
1298 | { | |
1299 | unsigned long flags; | |
1300 | struct bio_list bios; | |
1301 | struct bio *bio; | |
1302 | ||
1303 | bio_list_init(&bios); | |
1304 | ||
1305 | spin_lock_irqsave(&cache->lock, flags); | |
1306 | bio_list_merge(&bios, &cache->deferred_writethrough_bios); | |
1307 | bio_list_init(&cache->deferred_writethrough_bios); | |
1308 | spin_unlock_irqrestore(&cache->lock, flags); | |
1309 | ||
1310 | while ((bio = bio_list_pop(&bios))) | |
1311 | generic_make_request(bio); | |
1312 | } | |
1313 | ||
c6b4fcba JT |
1314 | static void writeback_some_dirty_blocks(struct cache *cache) |
1315 | { | |
1316 | int r = 0; | |
1317 | dm_oblock_t oblock; | |
1318 | dm_cblock_t cblock; | |
1319 | struct prealloc structs; | |
1320 | struct dm_bio_prison_cell *old_ocell; | |
1321 | ||
1322 | memset(&structs, 0, sizeof(structs)); | |
1323 | ||
1324 | while (spare_migration_bandwidth(cache)) { | |
1325 | if (prealloc_data_structs(cache, &structs)) | |
1326 | break; | |
1327 | ||
1328 | r = policy_writeback_work(cache->policy, &oblock, &cblock); | |
1329 | if (r) | |
1330 | break; | |
1331 | ||
1332 | r = get_cell(cache, oblock, &structs, &old_ocell); | |
1333 | if (r) { | |
1334 | policy_set_dirty(cache->policy, oblock); | |
1335 | break; | |
1336 | } | |
1337 | ||
1338 | writeback(cache, &structs, oblock, cblock, old_ocell); | |
1339 | } | |
1340 | ||
1341 | prealloc_free_structs(cache, &structs); | |
1342 | } | |
1343 | ||
1344 | /*---------------------------------------------------------------- | |
1345 | * Main worker loop | |
1346 | *--------------------------------------------------------------*/ | |
1347 | static void start_quiescing(struct cache *cache) | |
1348 | { | |
1349 | unsigned long flags; | |
1350 | ||
1351 | spin_lock_irqsave(&cache->lock, flags); | |
1352 | cache->quiescing = 1; | |
1353 | spin_unlock_irqrestore(&cache->lock, flags); | |
1354 | } | |
1355 | ||
1356 | static void stop_quiescing(struct cache *cache) | |
1357 | { | |
1358 | unsigned long flags; | |
1359 | ||
1360 | spin_lock_irqsave(&cache->lock, flags); | |
1361 | cache->quiescing = 0; | |
1362 | spin_unlock_irqrestore(&cache->lock, flags); | |
1363 | } | |
1364 | ||
1365 | static bool is_quiescing(struct cache *cache) | |
1366 | { | |
1367 | int r; | |
1368 | unsigned long flags; | |
1369 | ||
1370 | spin_lock_irqsave(&cache->lock, flags); | |
1371 | r = cache->quiescing; | |
1372 | spin_unlock_irqrestore(&cache->lock, flags); | |
1373 | ||
1374 | return r; | |
1375 | } | |
1376 | ||
1377 | static void wait_for_migrations(struct cache *cache) | |
1378 | { | |
1379 | wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations)); | |
1380 | } | |
1381 | ||
1382 | static void stop_worker(struct cache *cache) | |
1383 | { | |
1384 | cancel_delayed_work(&cache->waker); | |
1385 | flush_workqueue(cache->wq); | |
1386 | } | |
1387 | ||
1388 | static void requeue_deferred_io(struct cache *cache) | |
1389 | { | |
1390 | struct bio *bio; | |
1391 | struct bio_list bios; | |
1392 | ||
1393 | bio_list_init(&bios); | |
1394 | bio_list_merge(&bios, &cache->deferred_bios); | |
1395 | bio_list_init(&cache->deferred_bios); | |
1396 | ||
1397 | while ((bio = bio_list_pop(&bios))) | |
1398 | bio_endio(bio, DM_ENDIO_REQUEUE); | |
1399 | } | |
1400 | ||
1401 | static int more_work(struct cache *cache) | |
1402 | { | |
1403 | if (is_quiescing(cache)) | |
1404 | return !list_empty(&cache->quiesced_migrations) || | |
1405 | !list_empty(&cache->completed_migrations) || | |
1406 | !list_empty(&cache->need_commit_migrations); | |
1407 | else | |
1408 | return !bio_list_empty(&cache->deferred_bios) || | |
1409 | !bio_list_empty(&cache->deferred_flush_bios) || | |
e2e74d61 | 1410 | !bio_list_empty(&cache->deferred_writethrough_bios) || |
c6b4fcba JT |
1411 | !list_empty(&cache->quiesced_migrations) || |
1412 | !list_empty(&cache->completed_migrations) || | |
1413 | !list_empty(&cache->need_commit_migrations); | |
1414 | } | |
1415 | ||
1416 | static void do_worker(struct work_struct *ws) | |
1417 | { | |
1418 | struct cache *cache = container_of(ws, struct cache, worker); | |
1419 | ||
1420 | do { | |
1421 | if (!is_quiescing(cache)) | |
1422 | process_deferred_bios(cache); | |
1423 | ||
1424 | process_migrations(cache, &cache->quiesced_migrations, issue_copy); | |
1425 | process_migrations(cache, &cache->completed_migrations, complete_migration); | |
1426 | ||
1427 | writeback_some_dirty_blocks(cache); | |
1428 | ||
e2e74d61 JT |
1429 | process_deferred_writethrough_bios(cache); |
1430 | ||
c6b4fcba JT |
1431 | if (commit_if_needed(cache)) { |
1432 | process_deferred_flush_bios(cache, false); | |
1433 | ||
1434 | /* | |
1435 | * FIXME: rollback metadata or just go into a | |
1436 | * failure mode and error everything | |
1437 | */ | |
1438 | } else { | |
1439 | process_deferred_flush_bios(cache, true); | |
1440 | process_migrations(cache, &cache->need_commit_migrations, | |
1441 | migration_success_post_commit); | |
1442 | } | |
1443 | } while (more_work(cache)); | |
1444 | } | |
1445 | ||
1446 | /* | |
1447 | * We want to commit periodically so that not too much | |
1448 | * unwritten metadata builds up. | |
1449 | */ | |
1450 | static void do_waker(struct work_struct *ws) | |
1451 | { | |
1452 | struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker); | |
f8350daf | 1453 | policy_tick(cache->policy); |
c6b4fcba JT |
1454 | wake_worker(cache); |
1455 | queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); | |
1456 | } | |
1457 | ||
1458 | /*----------------------------------------------------------------*/ | |
1459 | ||
1460 | static int is_congested(struct dm_dev *dev, int bdi_bits) | |
1461 | { | |
1462 | struct request_queue *q = bdev_get_queue(dev->bdev); | |
1463 | return bdi_congested(&q->backing_dev_info, bdi_bits); | |
1464 | } | |
1465 | ||
1466 | static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits) | |
1467 | { | |
1468 | struct cache *cache = container_of(cb, struct cache, callbacks); | |
1469 | ||
1470 | return is_congested(cache->origin_dev, bdi_bits) || | |
1471 | is_congested(cache->cache_dev, bdi_bits); | |
1472 | } | |
1473 | ||
1474 | /*---------------------------------------------------------------- | |
1475 | * Target methods | |
1476 | *--------------------------------------------------------------*/ | |
1477 | ||
1478 | /* | |
1479 | * This function gets called on the error paths of the constructor, so we | |
1480 | * have to cope with a partially initialised struct. | |
1481 | */ | |
1482 | static void destroy(struct cache *cache) | |
1483 | { | |
1484 | unsigned i; | |
1485 | ||
1486 | if (cache->next_migration) | |
1487 | mempool_free(cache->next_migration, cache->migration_pool); | |
1488 | ||
1489 | if (cache->migration_pool) | |
1490 | mempool_destroy(cache->migration_pool); | |
1491 | ||
1492 | if (cache->all_io_ds) | |
1493 | dm_deferred_set_destroy(cache->all_io_ds); | |
1494 | ||
1495 | if (cache->prison) | |
1496 | dm_bio_prison_destroy(cache->prison); | |
1497 | ||
1498 | if (cache->wq) | |
1499 | destroy_workqueue(cache->wq); | |
1500 | ||
1501 | if (cache->dirty_bitset) | |
1502 | free_bitset(cache->dirty_bitset); | |
1503 | ||
1504 | if (cache->discard_bitset) | |
1505 | free_bitset(cache->discard_bitset); | |
1506 | ||
1507 | if (cache->copier) | |
1508 | dm_kcopyd_client_destroy(cache->copier); | |
1509 | ||
1510 | if (cache->cmd) | |
1511 | dm_cache_metadata_close(cache->cmd); | |
1512 | ||
1513 | if (cache->metadata_dev) | |
1514 | dm_put_device(cache->ti, cache->metadata_dev); | |
1515 | ||
1516 | if (cache->origin_dev) | |
1517 | dm_put_device(cache->ti, cache->origin_dev); | |
1518 | ||
1519 | if (cache->cache_dev) | |
1520 | dm_put_device(cache->ti, cache->cache_dev); | |
1521 | ||
1522 | if (cache->policy) | |
1523 | dm_cache_policy_destroy(cache->policy); | |
1524 | ||
1525 | for (i = 0; i < cache->nr_ctr_args ; i++) | |
1526 | kfree(cache->ctr_args[i]); | |
1527 | kfree(cache->ctr_args); | |
1528 | ||
1529 | kfree(cache); | |
1530 | } | |
1531 | ||
1532 | static void cache_dtr(struct dm_target *ti) | |
1533 | { | |
1534 | struct cache *cache = ti->private; | |
1535 | ||
1536 | destroy(cache); | |
1537 | } | |
1538 | ||
1539 | static sector_t get_dev_size(struct dm_dev *dev) | |
1540 | { | |
1541 | return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT; | |
1542 | } | |
1543 | ||
1544 | /*----------------------------------------------------------------*/ | |
1545 | ||
1546 | /* | |
1547 | * Construct a cache device mapping. | |
1548 | * | |
1549 | * cache <metadata dev> <cache dev> <origin dev> <block size> | |
1550 | * <#feature args> [<feature arg>]* | |
1551 | * <policy> <#policy args> [<policy arg>]* | |
1552 | * | |
1553 | * metadata dev : fast device holding the persistent metadata | |
1554 | * cache dev : fast device holding cached data blocks | |
1555 | * origin dev : slow device holding original data blocks | |
1556 | * block size : cache unit size in sectors | |
1557 | * | |
1558 | * #feature args : number of feature arguments passed | |
1559 | * feature args : writethrough. (The default is writeback.) | |
1560 | * | |
1561 | * policy : the replacement policy to use | |
1562 | * #policy args : an even number of policy arguments corresponding | |
1563 | * to key/value pairs passed to the policy | |
1564 | * policy args : key/value pairs passed to the policy | |
1565 | * E.g. 'sequential_threshold 1024' | |
1566 | * See cache-policies.txt for details. | |
1567 | * | |
1568 | * Optional feature arguments are: | |
1569 | * writethrough : write through caching that prohibits cache block | |
1570 | * content from being different from origin block content. | |
1571 | * Without this argument, the default behaviour is to write | |
1572 | * back cache block contents later for performance reasons, | |
1573 | * so they may differ from the corresponding origin blocks. | |
1574 | */ | |
1575 | struct cache_args { | |
1576 | struct dm_target *ti; | |
1577 | ||
1578 | struct dm_dev *metadata_dev; | |
1579 | ||
1580 | struct dm_dev *cache_dev; | |
1581 | sector_t cache_sectors; | |
1582 | ||
1583 | struct dm_dev *origin_dev; | |
1584 | sector_t origin_sectors; | |
1585 | ||
1586 | uint32_t block_size; | |
1587 | ||
1588 | const char *policy_name; | |
1589 | int policy_argc; | |
1590 | const char **policy_argv; | |
1591 | ||
1592 | struct cache_features features; | |
1593 | }; | |
1594 | ||
1595 | static void destroy_cache_args(struct cache_args *ca) | |
1596 | { | |
1597 | if (ca->metadata_dev) | |
1598 | dm_put_device(ca->ti, ca->metadata_dev); | |
1599 | ||
1600 | if (ca->cache_dev) | |
1601 | dm_put_device(ca->ti, ca->cache_dev); | |
1602 | ||
1603 | if (ca->origin_dev) | |
1604 | dm_put_device(ca->ti, ca->origin_dev); | |
1605 | ||
1606 | kfree(ca); | |
1607 | } | |
1608 | ||
1609 | static bool at_least_one_arg(struct dm_arg_set *as, char **error) | |
1610 | { | |
1611 | if (!as->argc) { | |
1612 | *error = "Insufficient args"; | |
1613 | return false; | |
1614 | } | |
1615 | ||
1616 | return true; | |
1617 | } | |
1618 | ||
1619 | static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1620 | char **error) | |
1621 | { | |
1622 | int r; | |
1623 | sector_t metadata_dev_size; | |
1624 | char b[BDEVNAME_SIZE]; | |
1625 | ||
1626 | if (!at_least_one_arg(as, error)) | |
1627 | return -EINVAL; | |
1628 | ||
1629 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1630 | &ca->metadata_dev); | |
1631 | if (r) { | |
1632 | *error = "Error opening metadata device"; | |
1633 | return r; | |
1634 | } | |
1635 | ||
1636 | metadata_dev_size = get_dev_size(ca->metadata_dev); | |
1637 | if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING) | |
1638 | DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", | |
1639 | bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS); | |
1640 | ||
1641 | return 0; | |
1642 | } | |
1643 | ||
1644 | static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1645 | char **error) | |
1646 | { | |
1647 | int r; | |
1648 | ||
1649 | if (!at_least_one_arg(as, error)) | |
1650 | return -EINVAL; | |
1651 | ||
1652 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1653 | &ca->cache_dev); | |
1654 | if (r) { | |
1655 | *error = "Error opening cache device"; | |
1656 | return r; | |
1657 | } | |
1658 | ca->cache_sectors = get_dev_size(ca->cache_dev); | |
1659 | ||
1660 | return 0; | |
1661 | } | |
1662 | ||
1663 | static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1664 | char **error) | |
1665 | { | |
1666 | int r; | |
1667 | ||
1668 | if (!at_least_one_arg(as, error)) | |
1669 | return -EINVAL; | |
1670 | ||
1671 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1672 | &ca->origin_dev); | |
1673 | if (r) { | |
1674 | *error = "Error opening origin device"; | |
1675 | return r; | |
1676 | } | |
1677 | ||
1678 | ca->origin_sectors = get_dev_size(ca->origin_dev); | |
1679 | if (ca->ti->len > ca->origin_sectors) { | |
1680 | *error = "Device size larger than cached device"; | |
1681 | return -EINVAL; | |
1682 | } | |
1683 | ||
1684 | return 0; | |
1685 | } | |
1686 | ||
1687 | static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, | |
1688 | char **error) | |
1689 | { | |
1690 | unsigned long tmp; | |
1691 | ||
1692 | if (!at_least_one_arg(as, error)) | |
1693 | return -EINVAL; | |
1694 | ||
1695 | if (kstrtoul(dm_shift_arg(as), 10, &tmp) || !tmp || | |
1696 | tmp < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || | |
1697 | tmp & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { | |
1698 | *error = "Invalid data block size"; | |
1699 | return -EINVAL; | |
1700 | } | |
1701 | ||
1702 | if (tmp > ca->cache_sectors) { | |
1703 | *error = "Data block size is larger than the cache device"; | |
1704 | return -EINVAL; | |
1705 | } | |
1706 | ||
1707 | ca->block_size = tmp; | |
1708 | ||
1709 | return 0; | |
1710 | } | |
1711 | ||
1712 | static void init_features(struct cache_features *cf) | |
1713 | { | |
1714 | cf->mode = CM_WRITE; | |
1715 | cf->write_through = false; | |
1716 | } | |
1717 | ||
1718 | static int parse_features(struct cache_args *ca, struct dm_arg_set *as, | |
1719 | char **error) | |
1720 | { | |
1721 | static struct dm_arg _args[] = { | |
1722 | {0, 1, "Invalid number of cache feature arguments"}, | |
1723 | }; | |
1724 | ||
1725 | int r; | |
1726 | unsigned argc; | |
1727 | const char *arg; | |
1728 | struct cache_features *cf = &ca->features; | |
1729 | ||
1730 | init_features(cf); | |
1731 | ||
1732 | r = dm_read_arg_group(_args, as, &argc, error); | |
1733 | if (r) | |
1734 | return -EINVAL; | |
1735 | ||
1736 | while (argc--) { | |
1737 | arg = dm_shift_arg(as); | |
1738 | ||
1739 | if (!strcasecmp(arg, "writeback")) | |
1740 | cf->write_through = false; | |
1741 | ||
1742 | else if (!strcasecmp(arg, "writethrough")) | |
1743 | cf->write_through = true; | |
1744 | ||
1745 | else { | |
1746 | *error = "Unrecognised cache feature requested"; | |
1747 | return -EINVAL; | |
1748 | } | |
1749 | } | |
1750 | ||
1751 | return 0; | |
1752 | } | |
1753 | ||
1754 | static int parse_policy(struct cache_args *ca, struct dm_arg_set *as, | |
1755 | char **error) | |
1756 | { | |
1757 | static struct dm_arg _args[] = { | |
1758 | {0, 1024, "Invalid number of policy arguments"}, | |
1759 | }; | |
1760 | ||
1761 | int r; | |
1762 | ||
1763 | if (!at_least_one_arg(as, error)) | |
1764 | return -EINVAL; | |
1765 | ||
1766 | ca->policy_name = dm_shift_arg(as); | |
1767 | ||
1768 | r = dm_read_arg_group(_args, as, &ca->policy_argc, error); | |
1769 | if (r) | |
1770 | return -EINVAL; | |
1771 | ||
1772 | ca->policy_argv = (const char **)as->argv; | |
1773 | dm_consume_args(as, ca->policy_argc); | |
1774 | ||
1775 | return 0; | |
1776 | } | |
1777 | ||
1778 | static int parse_cache_args(struct cache_args *ca, int argc, char **argv, | |
1779 | char **error) | |
1780 | { | |
1781 | int r; | |
1782 | struct dm_arg_set as; | |
1783 | ||
1784 | as.argc = argc; | |
1785 | as.argv = argv; | |
1786 | ||
1787 | r = parse_metadata_dev(ca, &as, error); | |
1788 | if (r) | |
1789 | return r; | |
1790 | ||
1791 | r = parse_cache_dev(ca, &as, error); | |
1792 | if (r) | |
1793 | return r; | |
1794 | ||
1795 | r = parse_origin_dev(ca, &as, error); | |
1796 | if (r) | |
1797 | return r; | |
1798 | ||
1799 | r = parse_block_size(ca, &as, error); | |
1800 | if (r) | |
1801 | return r; | |
1802 | ||
1803 | r = parse_features(ca, &as, error); | |
1804 | if (r) | |
1805 | return r; | |
1806 | ||
1807 | r = parse_policy(ca, &as, error); | |
1808 | if (r) | |
1809 | return r; | |
1810 | ||
1811 | return 0; | |
1812 | } | |
1813 | ||
1814 | /*----------------------------------------------------------------*/ | |
1815 | ||
1816 | static struct kmem_cache *migration_cache; | |
1817 | ||
2c73c471 AK |
1818 | #define NOT_CORE_OPTION 1 |
1819 | ||
2f14f4b5 | 1820 | static int process_config_option(struct cache *cache, const char *key, const char *value) |
2c73c471 AK |
1821 | { |
1822 | unsigned long tmp; | |
1823 | ||
2f14f4b5 JT |
1824 | if (!strcasecmp(key, "migration_threshold")) { |
1825 | if (kstrtoul(value, 10, &tmp)) | |
2c73c471 AK |
1826 | return -EINVAL; |
1827 | ||
1828 | cache->migration_threshold = tmp; | |
1829 | return 0; | |
1830 | } | |
1831 | ||
1832 | return NOT_CORE_OPTION; | |
1833 | } | |
1834 | ||
2f14f4b5 JT |
1835 | static int set_config_value(struct cache *cache, const char *key, const char *value) |
1836 | { | |
1837 | int r = process_config_option(cache, key, value); | |
1838 | ||
1839 | if (r == NOT_CORE_OPTION) | |
1840 | r = policy_set_config_value(cache->policy, key, value); | |
1841 | ||
1842 | if (r) | |
1843 | DMWARN("bad config value for %s: %s", key, value); | |
1844 | ||
1845 | return r; | |
1846 | } | |
1847 | ||
1848 | static int set_config_values(struct cache *cache, int argc, const char **argv) | |
c6b4fcba JT |
1849 | { |
1850 | int r = 0; | |
1851 | ||
1852 | if (argc & 1) { | |
1853 | DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs."); | |
1854 | return -EINVAL; | |
1855 | } | |
1856 | ||
1857 | while (argc) { | |
2f14f4b5 JT |
1858 | r = set_config_value(cache, argv[0], argv[1]); |
1859 | if (r) | |
1860 | break; | |
c6b4fcba JT |
1861 | |
1862 | argc -= 2; | |
1863 | argv += 2; | |
1864 | } | |
1865 | ||
1866 | return r; | |
1867 | } | |
1868 | ||
1869 | static int create_cache_policy(struct cache *cache, struct cache_args *ca, | |
1870 | char **error) | |
1871 | { | |
c6b4fcba JT |
1872 | cache->policy = dm_cache_policy_create(ca->policy_name, |
1873 | cache->cache_size, | |
1874 | cache->origin_sectors, | |
1875 | cache->sectors_per_block); | |
1876 | if (!cache->policy) { | |
1877 | *error = "Error creating cache's policy"; | |
1878 | return -ENOMEM; | |
1879 | } | |
1880 | ||
2f14f4b5 | 1881 | return 0; |
c6b4fcba JT |
1882 | } |
1883 | ||
1884 | /* | |
1885 | * We want the discard block size to be a power of two, at least the size | |
1886 | * of the cache block size, and have no more than 2^14 discard blocks | |
1887 | * across the origin. | |
1888 | */ | |
1889 | #define MAX_DISCARD_BLOCKS (1 << 14) | |
1890 | ||
1891 | static bool too_many_discard_blocks(sector_t discard_block_size, | |
1892 | sector_t origin_size) | |
1893 | { | |
1894 | (void) sector_div(origin_size, discard_block_size); | |
1895 | ||
1896 | return origin_size > MAX_DISCARD_BLOCKS; | |
1897 | } | |
1898 | ||
1899 | static sector_t calculate_discard_block_size(sector_t cache_block_size, | |
1900 | sector_t origin_size) | |
1901 | { | |
1902 | sector_t discard_block_size; | |
1903 | ||
1904 | discard_block_size = roundup_pow_of_two(cache_block_size); | |
1905 | ||
1906 | if (origin_size) | |
1907 | while (too_many_discard_blocks(discard_block_size, origin_size)) | |
1908 | discard_block_size *= 2; | |
1909 | ||
1910 | return discard_block_size; | |
1911 | } | |
1912 | ||
f8350daf | 1913 | #define DEFAULT_MIGRATION_THRESHOLD 2048 |
c6b4fcba | 1914 | |
c6b4fcba JT |
1915 | static int cache_create(struct cache_args *ca, struct cache **result) |
1916 | { | |
1917 | int r = 0; | |
1918 | char **error = &ca->ti->error; | |
1919 | struct cache *cache; | |
1920 | struct dm_target *ti = ca->ti; | |
1921 | dm_block_t origin_blocks; | |
1922 | struct dm_cache_metadata *cmd; | |
1923 | bool may_format = ca->features.mode == CM_WRITE; | |
1924 | ||
1925 | cache = kzalloc(sizeof(*cache), GFP_KERNEL); | |
1926 | if (!cache) | |
1927 | return -ENOMEM; | |
1928 | ||
1929 | cache->ti = ca->ti; | |
1930 | ti->private = cache; | |
c6b4fcba JT |
1931 | ti->num_flush_bios = 2; |
1932 | ti->flush_supported = true; | |
1933 | ||
1934 | ti->num_discard_bios = 1; | |
1935 | ti->discards_supported = true; | |
1936 | ti->discard_zeroes_data_unsupported = true; | |
1937 | ||
8c5008fa | 1938 | cache->features = ca->features; |
19b0092e | 1939 | ti->per_bio_data_size = get_per_bio_data_size(cache); |
c6b4fcba | 1940 | |
c6b4fcba JT |
1941 | cache->callbacks.congested_fn = cache_is_congested; |
1942 | dm_table_add_target_callbacks(ti->table, &cache->callbacks); | |
1943 | ||
1944 | cache->metadata_dev = ca->metadata_dev; | |
1945 | cache->origin_dev = ca->origin_dev; | |
1946 | cache->cache_dev = ca->cache_dev; | |
1947 | ||
1948 | ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; | |
1949 | ||
1950 | /* FIXME: factor out this whole section */ | |
1951 | origin_blocks = cache->origin_sectors = ca->origin_sectors; | |
414dd67d | 1952 | origin_blocks = block_div(origin_blocks, ca->block_size); |
c6b4fcba JT |
1953 | cache->origin_blocks = to_oblock(origin_blocks); |
1954 | ||
1955 | cache->sectors_per_block = ca->block_size; | |
1956 | if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) { | |
1957 | r = -EINVAL; | |
1958 | goto bad; | |
1959 | } | |
1960 | ||
1961 | if (ca->block_size & (ca->block_size - 1)) { | |
1962 | dm_block_t cache_size = ca->cache_sectors; | |
1963 | ||
1964 | cache->sectors_per_block_shift = -1; | |
414dd67d | 1965 | cache_size = block_div(cache_size, ca->block_size); |
c6b4fcba JT |
1966 | cache->cache_size = to_cblock(cache_size); |
1967 | } else { | |
1968 | cache->sectors_per_block_shift = __ffs(ca->block_size); | |
1969 | cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift); | |
1970 | } | |
1971 | ||
1972 | r = create_cache_policy(cache, ca, error); | |
1973 | if (r) | |
1974 | goto bad; | |
2f14f4b5 | 1975 | |
c6b4fcba | 1976 | cache->policy_nr_args = ca->policy_argc; |
2f14f4b5 JT |
1977 | cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD; |
1978 | ||
1979 | r = set_config_values(cache, ca->policy_argc, ca->policy_argv); | |
1980 | if (r) { | |
1981 | *error = "Error setting cache policy's config values"; | |
1982 | goto bad; | |
1983 | } | |
c6b4fcba JT |
1984 | |
1985 | cmd = dm_cache_metadata_open(cache->metadata_dev->bdev, | |
1986 | ca->block_size, may_format, | |
1987 | dm_cache_policy_get_hint_size(cache->policy)); | |
1988 | if (IS_ERR(cmd)) { | |
1989 | *error = "Error creating metadata object"; | |
1990 | r = PTR_ERR(cmd); | |
1991 | goto bad; | |
1992 | } | |
1993 | cache->cmd = cmd; | |
1994 | ||
1995 | spin_lock_init(&cache->lock); | |
1996 | bio_list_init(&cache->deferred_bios); | |
1997 | bio_list_init(&cache->deferred_flush_bios); | |
e2e74d61 | 1998 | bio_list_init(&cache->deferred_writethrough_bios); |
c6b4fcba JT |
1999 | INIT_LIST_HEAD(&cache->quiesced_migrations); |
2000 | INIT_LIST_HEAD(&cache->completed_migrations); | |
2001 | INIT_LIST_HEAD(&cache->need_commit_migrations); | |
c6b4fcba JT |
2002 | atomic_set(&cache->nr_migrations, 0); |
2003 | init_waitqueue_head(&cache->migration_wait); | |
2004 | ||
fa4d683a | 2005 | r = -ENOMEM; |
c6b4fcba JT |
2006 | cache->nr_dirty = 0; |
2007 | cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size)); | |
2008 | if (!cache->dirty_bitset) { | |
2009 | *error = "could not allocate dirty bitset"; | |
2010 | goto bad; | |
2011 | } | |
2012 | clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size)); | |
2013 | ||
2014 | cache->discard_block_size = | |
2015 | calculate_discard_block_size(cache->sectors_per_block, | |
2016 | cache->origin_sectors); | |
2017 | cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks); | |
2018 | cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks)); | |
2019 | if (!cache->discard_bitset) { | |
2020 | *error = "could not allocate discard bitset"; | |
2021 | goto bad; | |
2022 | } | |
2023 | clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); | |
2024 | ||
2025 | cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); | |
2026 | if (IS_ERR(cache->copier)) { | |
2027 | *error = "could not create kcopyd client"; | |
2028 | r = PTR_ERR(cache->copier); | |
2029 | goto bad; | |
2030 | } | |
2031 | ||
2032 | cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); | |
2033 | if (!cache->wq) { | |
2034 | *error = "could not create workqueue for metadata object"; | |
2035 | goto bad; | |
2036 | } | |
2037 | INIT_WORK(&cache->worker, do_worker); | |
2038 | INIT_DELAYED_WORK(&cache->waker, do_waker); | |
2039 | cache->last_commit_jiffies = jiffies; | |
2040 | ||
2041 | cache->prison = dm_bio_prison_create(PRISON_CELLS); | |
2042 | if (!cache->prison) { | |
2043 | *error = "could not create bio prison"; | |
2044 | goto bad; | |
2045 | } | |
2046 | ||
2047 | cache->all_io_ds = dm_deferred_set_create(); | |
2048 | if (!cache->all_io_ds) { | |
2049 | *error = "could not create all_io deferred set"; | |
2050 | goto bad; | |
2051 | } | |
2052 | ||
2053 | cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE, | |
2054 | migration_cache); | |
2055 | if (!cache->migration_pool) { | |
2056 | *error = "Error creating cache's migration mempool"; | |
2057 | goto bad; | |
2058 | } | |
2059 | ||
2060 | cache->next_migration = NULL; | |
2061 | ||
2062 | cache->need_tick_bio = true; | |
2063 | cache->sized = false; | |
2064 | cache->quiescing = false; | |
2065 | cache->commit_requested = false; | |
2066 | cache->loaded_mappings = false; | |
2067 | cache->loaded_discards = false; | |
2068 | ||
2069 | load_stats(cache); | |
2070 | ||
2071 | atomic_set(&cache->stats.demotion, 0); | |
2072 | atomic_set(&cache->stats.promotion, 0); | |
2073 | atomic_set(&cache->stats.copies_avoided, 0); | |
2074 | atomic_set(&cache->stats.cache_cell_clash, 0); | |
2075 | atomic_set(&cache->stats.commit_count, 0); | |
2076 | atomic_set(&cache->stats.discard_count, 0); | |
2077 | ||
2078 | *result = cache; | |
2079 | return 0; | |
2080 | ||
2081 | bad: | |
2082 | destroy(cache); | |
2083 | return r; | |
2084 | } | |
2085 | ||
2086 | static int copy_ctr_args(struct cache *cache, int argc, const char **argv) | |
2087 | { | |
2088 | unsigned i; | |
2089 | const char **copy; | |
2090 | ||
2091 | copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL); | |
2092 | if (!copy) | |
2093 | return -ENOMEM; | |
2094 | for (i = 0; i < argc; i++) { | |
2095 | copy[i] = kstrdup(argv[i], GFP_KERNEL); | |
2096 | if (!copy[i]) { | |
2097 | while (i--) | |
2098 | kfree(copy[i]); | |
2099 | kfree(copy); | |
2100 | return -ENOMEM; | |
2101 | } | |
2102 | } | |
2103 | ||
2104 | cache->nr_ctr_args = argc; | |
2105 | cache->ctr_args = copy; | |
2106 | ||
2107 | return 0; | |
2108 | } | |
2109 | ||
2110 | static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
2111 | { | |
2112 | int r = -EINVAL; | |
2113 | struct cache_args *ca; | |
2114 | struct cache *cache = NULL; | |
2115 | ||
2116 | ca = kzalloc(sizeof(*ca), GFP_KERNEL); | |
2117 | if (!ca) { | |
2118 | ti->error = "Error allocating memory for cache"; | |
2119 | return -ENOMEM; | |
2120 | } | |
2121 | ca->ti = ti; | |
2122 | ||
2123 | r = parse_cache_args(ca, argc, argv, &ti->error); | |
2124 | if (r) | |
2125 | goto out; | |
2126 | ||
2127 | r = cache_create(ca, &cache); | |
617a0b89 HM |
2128 | if (r) |
2129 | goto out; | |
c6b4fcba JT |
2130 | |
2131 | r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3); | |
2132 | if (r) { | |
2133 | destroy(cache); | |
2134 | goto out; | |
2135 | } | |
2136 | ||
2137 | ti->private = cache; | |
2138 | ||
2139 | out: | |
2140 | destroy_cache_args(ca); | |
2141 | return r; | |
2142 | } | |
2143 | ||
c6b4fcba JT |
2144 | static int cache_map(struct dm_target *ti, struct bio *bio) |
2145 | { | |
2146 | struct cache *cache = ti->private; | |
2147 | ||
2148 | int r; | |
2149 | dm_oblock_t block = get_bio_block(cache, bio); | |
19b0092e | 2150 | size_t pb_data_size = get_per_bio_data_size(cache); |
c6b4fcba JT |
2151 | bool can_migrate = false; |
2152 | bool discarded_block; | |
2153 | struct dm_bio_prison_cell *cell; | |
2154 | struct policy_result lookup_result; | |
2155 | struct per_bio_data *pb; | |
2156 | ||
2157 | if (from_oblock(block) > from_oblock(cache->origin_blocks)) { | |
2158 | /* | |
2159 | * This can only occur if the io goes to a partial block at | |
2160 | * the end of the origin device. We don't cache these. | |
2161 | * Just remap to the origin and carry on. | |
2162 | */ | |
2163 | remap_to_origin_clear_discard(cache, bio, block); | |
2164 | return DM_MAPIO_REMAPPED; | |
2165 | } | |
2166 | ||
19b0092e | 2167 | pb = init_per_bio_data(bio, pb_data_size); |
c6b4fcba JT |
2168 | |
2169 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) { | |
2170 | defer_bio(cache, bio); | |
2171 | return DM_MAPIO_SUBMITTED; | |
2172 | } | |
2173 | ||
2174 | /* | |
2175 | * Check to see if that block is currently migrating. | |
2176 | */ | |
2177 | cell = alloc_prison_cell(cache); | |
2178 | if (!cell) { | |
2179 | defer_bio(cache, bio); | |
2180 | return DM_MAPIO_SUBMITTED; | |
2181 | } | |
2182 | ||
2183 | r = bio_detain(cache, block, bio, cell, | |
2184 | (cell_free_fn) free_prison_cell, | |
2185 | cache, &cell); | |
2186 | if (r) { | |
2187 | if (r < 0) | |
2188 | defer_bio(cache, bio); | |
2189 | ||
2190 | return DM_MAPIO_SUBMITTED; | |
2191 | } | |
2192 | ||
2193 | discarded_block = is_discarded_oblock(cache, block); | |
2194 | ||
2195 | r = policy_map(cache->policy, block, false, can_migrate, discarded_block, | |
2196 | bio, &lookup_result); | |
2197 | if (r == -EWOULDBLOCK) { | |
2198 | cell_defer(cache, cell, true); | |
2199 | return DM_MAPIO_SUBMITTED; | |
2200 | ||
2201 | } else if (r) { | |
2202 | DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r); | |
2203 | bio_io_error(bio); | |
2204 | return DM_MAPIO_SUBMITTED; | |
2205 | } | |
2206 | ||
2207 | switch (lookup_result.op) { | |
2208 | case POLICY_HIT: | |
2209 | inc_hit_counter(cache, bio); | |
2210 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
2211 | ||
e2e74d61 JT |
2212 | if (is_writethrough_io(cache, bio, lookup_result.cblock)) |
2213 | remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); | |
2214 | else | |
c6b4fcba | 2215 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); |
e2e74d61 JT |
2216 | |
2217 | cell_defer(cache, cell, false); | |
c6b4fcba JT |
2218 | break; |
2219 | ||
2220 | case POLICY_MISS: | |
2221 | inc_miss_counter(cache, bio); | |
2222 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
2223 | ||
2224 | if (pb->req_nr != 0) { | |
2225 | /* | |
2226 | * This is a duplicate writethrough io that is no | |
2227 | * longer needed because the block has been demoted. | |
2228 | */ | |
2229 | bio_endio(bio, 0); | |
2230 | cell_defer(cache, cell, false); | |
2231 | return DM_MAPIO_SUBMITTED; | |
2232 | } else { | |
2233 | remap_to_origin_clear_discard(cache, bio, block); | |
2234 | cell_defer(cache, cell, false); | |
2235 | } | |
2236 | break; | |
2237 | ||
2238 | default: | |
2239 | DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__, | |
2240 | (unsigned) lookup_result.op); | |
2241 | bio_io_error(bio); | |
2242 | return DM_MAPIO_SUBMITTED; | |
2243 | } | |
2244 | ||
2245 | return DM_MAPIO_REMAPPED; | |
2246 | } | |
2247 | ||
2248 | static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) | |
2249 | { | |
2250 | struct cache *cache = ti->private; | |
2251 | unsigned long flags; | |
19b0092e MS |
2252 | size_t pb_data_size = get_per_bio_data_size(cache); |
2253 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
2254 | |
2255 | if (pb->tick) { | |
2256 | policy_tick(cache->policy); | |
2257 | ||
2258 | spin_lock_irqsave(&cache->lock, flags); | |
2259 | cache->need_tick_bio = true; | |
2260 | spin_unlock_irqrestore(&cache->lock, flags); | |
2261 | } | |
2262 | ||
2263 | check_for_quiesced_migrations(cache, pb); | |
2264 | ||
2265 | return 0; | |
2266 | } | |
2267 | ||
2268 | static int write_dirty_bitset(struct cache *cache) | |
2269 | { | |
2270 | unsigned i, r; | |
2271 | ||
2272 | for (i = 0; i < from_cblock(cache->cache_size); i++) { | |
2273 | r = dm_cache_set_dirty(cache->cmd, to_cblock(i), | |
2274 | is_dirty(cache, to_cblock(i))); | |
2275 | if (r) | |
2276 | return r; | |
2277 | } | |
2278 | ||
2279 | return 0; | |
2280 | } | |
2281 | ||
2282 | static int write_discard_bitset(struct cache *cache) | |
2283 | { | |
2284 | unsigned i, r; | |
2285 | ||
2286 | r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size, | |
2287 | cache->discard_nr_blocks); | |
2288 | if (r) { | |
2289 | DMERR("could not resize on-disk discard bitset"); | |
2290 | return r; | |
2291 | } | |
2292 | ||
2293 | for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) { | |
2294 | r = dm_cache_set_discard(cache->cmd, to_dblock(i), | |
2295 | is_discarded(cache, to_dblock(i))); | |
2296 | if (r) | |
2297 | return r; | |
2298 | } | |
2299 | ||
2300 | return 0; | |
2301 | } | |
2302 | ||
2303 | static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, | |
2304 | uint32_t hint) | |
2305 | { | |
2306 | struct cache *cache = context; | |
2307 | return dm_cache_save_hint(cache->cmd, cblock, hint); | |
2308 | } | |
2309 | ||
2310 | static int write_hints(struct cache *cache) | |
2311 | { | |
2312 | int r; | |
2313 | ||
2314 | r = dm_cache_begin_hints(cache->cmd, cache->policy); | |
2315 | if (r) { | |
2316 | DMERR("dm_cache_begin_hints failed"); | |
2317 | return r; | |
2318 | } | |
2319 | ||
2320 | r = policy_walk_mappings(cache->policy, save_hint, cache); | |
2321 | if (r) | |
2322 | DMERR("policy_walk_mappings failed"); | |
2323 | ||
2324 | return r; | |
2325 | } | |
2326 | ||
2327 | /* | |
2328 | * returns true on success | |
2329 | */ | |
2330 | static bool sync_metadata(struct cache *cache) | |
2331 | { | |
2332 | int r1, r2, r3, r4; | |
2333 | ||
2334 | r1 = write_dirty_bitset(cache); | |
2335 | if (r1) | |
2336 | DMERR("could not write dirty bitset"); | |
2337 | ||
2338 | r2 = write_discard_bitset(cache); | |
2339 | if (r2) | |
2340 | DMERR("could not write discard bitset"); | |
2341 | ||
2342 | save_stats(cache); | |
2343 | ||
2344 | r3 = write_hints(cache); | |
2345 | if (r3) | |
2346 | DMERR("could not write hints"); | |
2347 | ||
2348 | /* | |
2349 | * If writing the above metadata failed, we still commit, but don't | |
2350 | * set the clean shutdown flag. This will effectively force every | |
2351 | * dirty bit to be set on reload. | |
2352 | */ | |
2353 | r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3); | |
2354 | if (r4) | |
2355 | DMERR("could not write cache metadata. Data loss may occur."); | |
2356 | ||
2357 | return !r1 && !r2 && !r3 && !r4; | |
2358 | } | |
2359 | ||
2360 | static void cache_postsuspend(struct dm_target *ti) | |
2361 | { | |
2362 | struct cache *cache = ti->private; | |
2363 | ||
2364 | start_quiescing(cache); | |
2365 | wait_for_migrations(cache); | |
2366 | stop_worker(cache); | |
2367 | requeue_deferred_io(cache); | |
2368 | stop_quiescing(cache); | |
2369 | ||
2370 | (void) sync_metadata(cache); | |
2371 | } | |
2372 | ||
2373 | static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, | |
2374 | bool dirty, uint32_t hint, bool hint_valid) | |
2375 | { | |
2376 | int r; | |
2377 | struct cache *cache = context; | |
2378 | ||
2379 | r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid); | |
2380 | if (r) | |
2381 | return r; | |
2382 | ||
2383 | if (dirty) | |
2384 | set_dirty(cache, oblock, cblock); | |
2385 | else | |
2386 | clear_dirty(cache, oblock, cblock); | |
2387 | ||
2388 | return 0; | |
2389 | } | |
2390 | ||
2391 | static int load_discard(void *context, sector_t discard_block_size, | |
2392 | dm_dblock_t dblock, bool discard) | |
2393 | { | |
2394 | struct cache *cache = context; | |
2395 | ||
2396 | /* FIXME: handle mis-matched block size */ | |
2397 | ||
2398 | if (discard) | |
2399 | set_discard(cache, dblock); | |
2400 | else | |
2401 | clear_discard(cache, dblock); | |
2402 | ||
2403 | return 0; | |
2404 | } | |
2405 | ||
2406 | static int cache_preresume(struct dm_target *ti) | |
2407 | { | |
2408 | int r = 0; | |
2409 | struct cache *cache = ti->private; | |
2410 | sector_t actual_cache_size = get_dev_size(cache->cache_dev); | |
2411 | (void) sector_div(actual_cache_size, cache->sectors_per_block); | |
2412 | ||
2413 | /* | |
2414 | * Check to see if the cache has resized. | |
2415 | */ | |
2416 | if (from_cblock(cache->cache_size) != actual_cache_size || !cache->sized) { | |
2417 | cache->cache_size = to_cblock(actual_cache_size); | |
2418 | ||
2419 | r = dm_cache_resize(cache->cmd, cache->cache_size); | |
2420 | if (r) { | |
2421 | DMERR("could not resize cache metadata"); | |
2422 | return r; | |
2423 | } | |
2424 | ||
2425 | cache->sized = true; | |
2426 | } | |
2427 | ||
2428 | if (!cache->loaded_mappings) { | |
ea2dd8c1 | 2429 | r = dm_cache_load_mappings(cache->cmd, cache->policy, |
c6b4fcba JT |
2430 | load_mapping, cache); |
2431 | if (r) { | |
2432 | DMERR("could not load cache mappings"); | |
2433 | return r; | |
2434 | } | |
2435 | ||
2436 | cache->loaded_mappings = true; | |
2437 | } | |
2438 | ||
2439 | if (!cache->loaded_discards) { | |
2440 | r = dm_cache_load_discards(cache->cmd, load_discard, cache); | |
2441 | if (r) { | |
2442 | DMERR("could not load origin discards"); | |
2443 | return r; | |
2444 | } | |
2445 | ||
2446 | cache->loaded_discards = true; | |
2447 | } | |
2448 | ||
2449 | return r; | |
2450 | } | |
2451 | ||
2452 | static void cache_resume(struct dm_target *ti) | |
2453 | { | |
2454 | struct cache *cache = ti->private; | |
2455 | ||
2456 | cache->need_tick_bio = true; | |
2457 | do_waker(&cache->waker.work); | |
2458 | } | |
2459 | ||
2460 | /* | |
2461 | * Status format: | |
2462 | * | |
2463 | * <#used metadata blocks>/<#total metadata blocks> | |
2464 | * <#read hits> <#read misses> <#write hits> <#write misses> | |
2465 | * <#demotions> <#promotions> <#blocks in cache> <#dirty> | |
2466 | * <#features> <features>* | |
2467 | * <#core args> <core args> | |
2468 | * <#policy args> <policy args>* | |
2469 | */ | |
2470 | static void cache_status(struct dm_target *ti, status_type_t type, | |
2471 | unsigned status_flags, char *result, unsigned maxlen) | |
2472 | { | |
2473 | int r = 0; | |
2474 | unsigned i; | |
2475 | ssize_t sz = 0; | |
2476 | dm_block_t nr_free_blocks_metadata = 0; | |
2477 | dm_block_t nr_blocks_metadata = 0; | |
2478 | char buf[BDEVNAME_SIZE]; | |
2479 | struct cache *cache = ti->private; | |
2480 | dm_cblock_t residency; | |
2481 | ||
2482 | switch (type) { | |
2483 | case STATUSTYPE_INFO: | |
2484 | /* Commit to ensure statistics aren't out-of-date */ | |
2485 | if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) { | |
2486 | r = dm_cache_commit(cache->cmd, false); | |
2487 | if (r) | |
2488 | DMERR("could not commit metadata for accurate status"); | |
2489 | } | |
2490 | ||
2491 | r = dm_cache_get_free_metadata_block_count(cache->cmd, | |
2492 | &nr_free_blocks_metadata); | |
2493 | if (r) { | |
2494 | DMERR("could not get metadata free block count"); | |
2495 | goto err; | |
2496 | } | |
2497 | ||
2498 | r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata); | |
2499 | if (r) { | |
2500 | DMERR("could not get metadata device size"); | |
2501 | goto err; | |
2502 | } | |
2503 | ||
2504 | residency = policy_residency(cache->policy); | |
2505 | ||
2506 | DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ", | |
2507 | (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), | |
2508 | (unsigned long long)nr_blocks_metadata, | |
2509 | (unsigned) atomic_read(&cache->stats.read_hit), | |
2510 | (unsigned) atomic_read(&cache->stats.read_miss), | |
2511 | (unsigned) atomic_read(&cache->stats.write_hit), | |
2512 | (unsigned) atomic_read(&cache->stats.write_miss), | |
2513 | (unsigned) atomic_read(&cache->stats.demotion), | |
2514 | (unsigned) atomic_read(&cache->stats.promotion), | |
2515 | (unsigned long long) from_cblock(residency), | |
2516 | cache->nr_dirty); | |
2517 | ||
2518 | if (cache->features.write_through) | |
2519 | DMEMIT("1 writethrough "); | |
2520 | else | |
2521 | DMEMIT("0 "); | |
2522 | ||
2523 | DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold); | |
2524 | if (sz < maxlen) { | |
2525 | r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz); | |
2526 | if (r) | |
2527 | DMERR("policy_emit_config_values returned %d", r); | |
2528 | } | |
2529 | ||
2530 | break; | |
2531 | ||
2532 | case STATUSTYPE_TABLE: | |
2533 | format_dev_t(buf, cache->metadata_dev->bdev->bd_dev); | |
2534 | DMEMIT("%s ", buf); | |
2535 | format_dev_t(buf, cache->cache_dev->bdev->bd_dev); | |
2536 | DMEMIT("%s ", buf); | |
2537 | format_dev_t(buf, cache->origin_dev->bdev->bd_dev); | |
2538 | DMEMIT("%s", buf); | |
2539 | ||
2540 | for (i = 0; i < cache->nr_ctr_args - 1; i++) | |
2541 | DMEMIT(" %s", cache->ctr_args[i]); | |
2542 | if (cache->nr_ctr_args) | |
2543 | DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]); | |
2544 | } | |
2545 | ||
2546 | return; | |
2547 | ||
2548 | err: | |
2549 | DMEMIT("Error"); | |
2550 | } | |
2551 | ||
c6b4fcba JT |
2552 | /* |
2553 | * Supports <key> <value>. | |
2554 | * | |
2555 | * The key migration_threshold is supported by the cache target core. | |
2556 | */ | |
2557 | static int cache_message(struct dm_target *ti, unsigned argc, char **argv) | |
2558 | { | |
c6b4fcba JT |
2559 | struct cache *cache = ti->private; |
2560 | ||
2561 | if (argc != 2) | |
2562 | return -EINVAL; | |
2563 | ||
2f14f4b5 | 2564 | return set_config_value(cache, argv[0], argv[1]); |
c6b4fcba JT |
2565 | } |
2566 | ||
2567 | static int cache_iterate_devices(struct dm_target *ti, | |
2568 | iterate_devices_callout_fn fn, void *data) | |
2569 | { | |
2570 | int r = 0; | |
2571 | struct cache *cache = ti->private; | |
2572 | ||
2573 | r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data); | |
2574 | if (!r) | |
2575 | r = fn(ti, cache->origin_dev, 0, ti->len, data); | |
2576 | ||
2577 | return r; | |
2578 | } | |
2579 | ||
2580 | /* | |
2581 | * We assume I/O is going to the origin (which is the volume | |
2582 | * more likely to have restrictions e.g. by being striped). | |
2583 | * (Looking up the exact location of the data would be expensive | |
2584 | * and could always be out of date by the time the bio is submitted.) | |
2585 | */ | |
2586 | static int cache_bvec_merge(struct dm_target *ti, | |
2587 | struct bvec_merge_data *bvm, | |
2588 | struct bio_vec *biovec, int max_size) | |
2589 | { | |
2590 | struct cache *cache = ti->private; | |
2591 | struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev); | |
2592 | ||
2593 | if (!q->merge_bvec_fn) | |
2594 | return max_size; | |
2595 | ||
2596 | bvm->bi_bdev = cache->origin_dev->bdev; | |
2597 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
2598 | } | |
2599 | ||
2600 | static void set_discard_limits(struct cache *cache, struct queue_limits *limits) | |
2601 | { | |
2602 | /* | |
2603 | * FIXME: these limits may be incompatible with the cache device | |
2604 | */ | |
2605 | limits->max_discard_sectors = cache->discard_block_size * 1024; | |
2606 | limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT; | |
2607 | } | |
2608 | ||
2609 | static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
2610 | { | |
2611 | struct cache *cache = ti->private; | |
2612 | ||
2613 | blk_limits_io_min(limits, 0); | |
2614 | blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT); | |
2615 | set_discard_limits(cache, limits); | |
2616 | } | |
2617 | ||
2618 | /*----------------------------------------------------------------*/ | |
2619 | ||
2620 | static struct target_type cache_target = { | |
2621 | .name = "cache", | |
2f14f4b5 | 2622 | .version = {1, 1, 1}, |
c6b4fcba JT |
2623 | .module = THIS_MODULE, |
2624 | .ctr = cache_ctr, | |
2625 | .dtr = cache_dtr, | |
2626 | .map = cache_map, | |
2627 | .end_io = cache_end_io, | |
2628 | .postsuspend = cache_postsuspend, | |
2629 | .preresume = cache_preresume, | |
2630 | .resume = cache_resume, | |
2631 | .status = cache_status, | |
2632 | .message = cache_message, | |
2633 | .iterate_devices = cache_iterate_devices, | |
2634 | .merge = cache_bvec_merge, | |
2635 | .io_hints = cache_io_hints, | |
2636 | }; | |
2637 | ||
2638 | static int __init dm_cache_init(void) | |
2639 | { | |
2640 | int r; | |
2641 | ||
2642 | r = dm_register_target(&cache_target); | |
2643 | if (r) { | |
2644 | DMERR("cache target registration failed: %d", r); | |
2645 | return r; | |
2646 | } | |
2647 | ||
2648 | migration_cache = KMEM_CACHE(dm_cache_migration, 0); | |
2649 | if (!migration_cache) { | |
2650 | dm_unregister_target(&cache_target); | |
2651 | return -ENOMEM; | |
2652 | } | |
2653 | ||
2654 | return 0; | |
2655 | } | |
2656 | ||
2657 | static void __exit dm_cache_exit(void) | |
2658 | { | |
2659 | dm_unregister_target(&cache_target); | |
2660 | kmem_cache_destroy(migration_cache); | |
2661 | } | |
2662 | ||
2663 | module_init(dm_cache_init); | |
2664 | module_exit(dm_cache_exit); | |
2665 | ||
2666 | MODULE_DESCRIPTION(DM_NAME " cache target"); | |
2667 | MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); | |
2668 | MODULE_LICENSE("GPL"); |