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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 | /* | |
05473044 MS |
70 | * The block size of the device holding cache data must be |
71 | * between 32KB and 1GB. | |
c6b4fcba JT |
72 | */ |
73 | #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) | |
05473044 | 74 | #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) |
c6b4fcba JT |
75 | |
76 | /* | |
77 | * FIXME: the cache is read/write for the time being. | |
78 | */ | |
79 | enum cache_mode { | |
80 | CM_WRITE, /* metadata may be changed */ | |
81 | CM_READ_ONLY, /* metadata may not be changed */ | |
82 | }; | |
83 | ||
84 | struct cache_features { | |
85 | enum cache_mode mode; | |
86 | bool write_through:1; | |
87 | }; | |
88 | ||
89 | struct cache_stats { | |
90 | atomic_t read_hit; | |
91 | atomic_t read_miss; | |
92 | atomic_t write_hit; | |
93 | atomic_t write_miss; | |
94 | atomic_t demotion; | |
95 | atomic_t promotion; | |
96 | atomic_t copies_avoided; | |
97 | atomic_t cache_cell_clash; | |
98 | atomic_t commit_count; | |
99 | atomic_t discard_count; | |
100 | }; | |
101 | ||
102 | struct cache { | |
103 | struct dm_target *ti; | |
104 | struct dm_target_callbacks callbacks; | |
105 | ||
106 | /* | |
107 | * Metadata is written to this device. | |
108 | */ | |
109 | struct dm_dev *metadata_dev; | |
110 | ||
111 | /* | |
112 | * The slower of the two data devices. Typically a spindle. | |
113 | */ | |
114 | struct dm_dev *origin_dev; | |
115 | ||
116 | /* | |
117 | * The faster of the two data devices. Typically an SSD. | |
118 | */ | |
119 | struct dm_dev *cache_dev; | |
120 | ||
121 | /* | |
122 | * Cache features such as write-through. | |
123 | */ | |
124 | struct cache_features features; | |
125 | ||
126 | /* | |
127 | * Size of the origin device in _complete_ blocks and native sectors. | |
128 | */ | |
129 | dm_oblock_t origin_blocks; | |
130 | sector_t origin_sectors; | |
131 | ||
132 | /* | |
133 | * Size of the cache device in blocks. | |
134 | */ | |
135 | dm_cblock_t cache_size; | |
136 | ||
137 | /* | |
138 | * Fields for converting from sectors to blocks. | |
139 | */ | |
140 | uint32_t sectors_per_block; | |
141 | int sectors_per_block_shift; | |
142 | ||
143 | struct dm_cache_metadata *cmd; | |
144 | ||
145 | spinlock_t lock; | |
146 | struct bio_list deferred_bios; | |
147 | struct bio_list deferred_flush_bios; | |
e2e74d61 | 148 | struct bio_list deferred_writethrough_bios; |
c6b4fcba JT |
149 | struct list_head quiesced_migrations; |
150 | struct list_head completed_migrations; | |
151 | struct list_head need_commit_migrations; | |
152 | sector_t migration_threshold; | |
153 | atomic_t nr_migrations; | |
154 | wait_queue_head_t migration_wait; | |
155 | ||
156 | /* | |
157 | * cache_size entries, dirty if set | |
158 | */ | |
159 | dm_cblock_t nr_dirty; | |
160 | unsigned long *dirty_bitset; | |
161 | ||
162 | /* | |
163 | * origin_blocks entries, discarded if set. | |
164 | */ | |
414dd67d | 165 | uint32_t discard_block_size; /* a power of 2 times sectors per block */ |
c6b4fcba JT |
166 | dm_dblock_t discard_nr_blocks; |
167 | unsigned long *discard_bitset; | |
168 | ||
169 | struct dm_kcopyd_client *copier; | |
170 | struct workqueue_struct *wq; | |
171 | struct work_struct worker; | |
172 | ||
173 | struct delayed_work waker; | |
174 | unsigned long last_commit_jiffies; | |
175 | ||
176 | struct dm_bio_prison *prison; | |
177 | struct dm_deferred_set *all_io_ds; | |
178 | ||
179 | mempool_t *migration_pool; | |
180 | struct dm_cache_migration *next_migration; | |
181 | ||
182 | struct dm_cache_policy *policy; | |
183 | unsigned policy_nr_args; | |
184 | ||
185 | bool need_tick_bio:1; | |
186 | bool sized:1; | |
187 | bool quiescing:1; | |
188 | bool commit_requested:1; | |
189 | bool loaded_mappings:1; | |
190 | bool loaded_discards:1; | |
191 | ||
192 | struct cache_stats stats; | |
193 | ||
194 | /* | |
195 | * Rather than reconstructing the table line for the status we just | |
196 | * save it and regurgitate. | |
197 | */ | |
198 | unsigned nr_ctr_args; | |
199 | const char **ctr_args; | |
200 | }; | |
201 | ||
202 | struct per_bio_data { | |
203 | bool tick:1; | |
204 | unsigned req_nr:2; | |
205 | struct dm_deferred_entry *all_io_entry; | |
e2e74d61 | 206 | |
19b0092e MS |
207 | /* |
208 | * writethrough fields. These MUST remain at the end of this | |
209 | * structure and the 'cache' member must be the first as it | |
aeed1420 | 210 | * is used to determine the offset of the writethrough fields. |
19b0092e | 211 | */ |
e2e74d61 JT |
212 | struct cache *cache; |
213 | dm_cblock_t cblock; | |
214 | bio_end_io_t *saved_bi_end_io; | |
b844fe69 | 215 | struct dm_bio_details bio_details; |
c6b4fcba JT |
216 | }; |
217 | ||
218 | struct dm_cache_migration { | |
219 | struct list_head list; | |
220 | struct cache *cache; | |
221 | ||
222 | unsigned long start_jiffies; | |
223 | dm_oblock_t old_oblock; | |
224 | dm_oblock_t new_oblock; | |
225 | dm_cblock_t cblock; | |
226 | ||
227 | bool err:1; | |
228 | bool writeback:1; | |
229 | bool demote:1; | |
230 | bool promote:1; | |
231 | ||
232 | struct dm_bio_prison_cell *old_ocell; | |
233 | struct dm_bio_prison_cell *new_ocell; | |
234 | }; | |
235 | ||
236 | /* | |
237 | * Processing a bio in the worker thread may require these memory | |
238 | * allocations. We prealloc to avoid deadlocks (the same worker thread | |
239 | * frees them back to the mempool). | |
240 | */ | |
241 | struct prealloc { | |
242 | struct dm_cache_migration *mg; | |
243 | struct dm_bio_prison_cell *cell1; | |
244 | struct dm_bio_prison_cell *cell2; | |
245 | }; | |
246 | ||
247 | static void wake_worker(struct cache *cache) | |
248 | { | |
249 | queue_work(cache->wq, &cache->worker); | |
250 | } | |
251 | ||
252 | /*----------------------------------------------------------------*/ | |
253 | ||
254 | static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache) | |
255 | { | |
256 | /* FIXME: change to use a local slab. */ | |
257 | return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT); | |
258 | } | |
259 | ||
260 | static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell) | |
261 | { | |
262 | dm_bio_prison_free_cell(cache->prison, cell); | |
263 | } | |
264 | ||
265 | static int prealloc_data_structs(struct cache *cache, struct prealloc *p) | |
266 | { | |
267 | if (!p->mg) { | |
268 | p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT); | |
269 | if (!p->mg) | |
270 | return -ENOMEM; | |
271 | } | |
272 | ||
273 | if (!p->cell1) { | |
274 | p->cell1 = alloc_prison_cell(cache); | |
275 | if (!p->cell1) | |
276 | return -ENOMEM; | |
277 | } | |
278 | ||
279 | if (!p->cell2) { | |
280 | p->cell2 = alloc_prison_cell(cache); | |
281 | if (!p->cell2) | |
282 | return -ENOMEM; | |
283 | } | |
284 | ||
285 | return 0; | |
286 | } | |
287 | ||
288 | static void prealloc_free_structs(struct cache *cache, struct prealloc *p) | |
289 | { | |
290 | if (p->cell2) | |
291 | free_prison_cell(cache, p->cell2); | |
292 | ||
293 | if (p->cell1) | |
294 | free_prison_cell(cache, p->cell1); | |
295 | ||
296 | if (p->mg) | |
297 | mempool_free(p->mg, cache->migration_pool); | |
298 | } | |
299 | ||
300 | static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p) | |
301 | { | |
302 | struct dm_cache_migration *mg = p->mg; | |
303 | ||
304 | BUG_ON(!mg); | |
305 | p->mg = NULL; | |
306 | ||
307 | return mg; | |
308 | } | |
309 | ||
310 | /* | |
311 | * You must have a cell within the prealloc struct to return. If not this | |
312 | * function will BUG() rather than returning NULL. | |
313 | */ | |
314 | static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p) | |
315 | { | |
316 | struct dm_bio_prison_cell *r = NULL; | |
317 | ||
318 | if (p->cell1) { | |
319 | r = p->cell1; | |
320 | p->cell1 = NULL; | |
321 | ||
322 | } else if (p->cell2) { | |
323 | r = p->cell2; | |
324 | p->cell2 = NULL; | |
325 | } else | |
326 | BUG(); | |
327 | ||
328 | return r; | |
329 | } | |
330 | ||
331 | /* | |
332 | * You can't have more than two cells in a prealloc struct. BUG() will be | |
333 | * called if you try and overfill. | |
334 | */ | |
335 | static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell) | |
336 | { | |
337 | if (!p->cell2) | |
338 | p->cell2 = cell; | |
339 | ||
340 | else if (!p->cell1) | |
341 | p->cell1 = cell; | |
342 | ||
343 | else | |
344 | BUG(); | |
345 | } | |
346 | ||
347 | /*----------------------------------------------------------------*/ | |
348 | ||
349 | static void build_key(dm_oblock_t oblock, struct dm_cell_key *key) | |
350 | { | |
351 | key->virtual = 0; | |
352 | key->dev = 0; | |
353 | key->block = from_oblock(oblock); | |
354 | } | |
355 | ||
356 | /* | |
357 | * The caller hands in a preallocated cell, and a free function for it. | |
358 | * The cell will be freed if there's an error, or if it wasn't used because | |
359 | * a cell with that key already exists. | |
360 | */ | |
361 | typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell); | |
362 | ||
363 | static int bio_detain(struct cache *cache, dm_oblock_t oblock, | |
364 | struct bio *bio, struct dm_bio_prison_cell *cell_prealloc, | |
365 | cell_free_fn free_fn, void *free_context, | |
366 | struct dm_bio_prison_cell **cell_result) | |
367 | { | |
368 | int r; | |
369 | struct dm_cell_key key; | |
370 | ||
371 | build_key(oblock, &key); | |
372 | r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result); | |
373 | if (r) | |
374 | free_fn(free_context, cell_prealloc); | |
375 | ||
376 | return r; | |
377 | } | |
378 | ||
379 | static int get_cell(struct cache *cache, | |
380 | dm_oblock_t oblock, | |
381 | struct prealloc *structs, | |
382 | struct dm_bio_prison_cell **cell_result) | |
383 | { | |
384 | int r; | |
385 | struct dm_cell_key key; | |
386 | struct dm_bio_prison_cell *cell_prealloc; | |
387 | ||
388 | cell_prealloc = prealloc_get_cell(structs); | |
389 | ||
390 | build_key(oblock, &key); | |
391 | r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result); | |
392 | if (r) | |
393 | prealloc_put_cell(structs, cell_prealloc); | |
394 | ||
395 | return r; | |
396 | } | |
397 | ||
aeed1420 | 398 | /*----------------------------------------------------------------*/ |
c6b4fcba JT |
399 | |
400 | static bool is_dirty(struct cache *cache, dm_cblock_t b) | |
401 | { | |
402 | return test_bit(from_cblock(b), cache->dirty_bitset); | |
403 | } | |
404 | ||
405 | static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | |
406 | { | |
407 | if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
408 | cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) + 1); | |
409 | policy_set_dirty(cache->policy, oblock); | |
410 | } | |
411 | } | |
412 | ||
413 | static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | |
414 | { | |
415 | if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
416 | policy_clear_dirty(cache->policy, oblock); | |
417 | cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) - 1); | |
418 | if (!from_cblock(cache->nr_dirty)) | |
419 | dm_table_event(cache->ti->table); | |
420 | } | |
421 | } | |
422 | ||
423 | /*----------------------------------------------------------------*/ | |
aeed1420 | 424 | |
c6b4fcba JT |
425 | static bool block_size_is_power_of_two(struct cache *cache) |
426 | { | |
427 | return cache->sectors_per_block_shift >= 0; | |
428 | } | |
429 | ||
43aeaa29 MP |
430 | /* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */ |
431 | #if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6 | |
432 | __always_inline | |
433 | #endif | |
414dd67d JT |
434 | static dm_block_t block_div(dm_block_t b, uint32_t n) |
435 | { | |
436 | do_div(b, n); | |
437 | ||
438 | return b; | |
439 | } | |
440 | ||
c6b4fcba JT |
441 | static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) |
442 | { | |
414dd67d | 443 | uint32_t discard_blocks = cache->discard_block_size; |
c6b4fcba JT |
444 | dm_block_t b = from_oblock(oblock); |
445 | ||
446 | if (!block_size_is_power_of_two(cache)) | |
414dd67d | 447 | discard_blocks = discard_blocks / cache->sectors_per_block; |
c6b4fcba JT |
448 | else |
449 | discard_blocks >>= cache->sectors_per_block_shift; | |
450 | ||
414dd67d | 451 | b = block_div(b, discard_blocks); |
c6b4fcba JT |
452 | |
453 | return to_dblock(b); | |
454 | } | |
455 | ||
456 | static void set_discard(struct cache *cache, dm_dblock_t b) | |
457 | { | |
458 | unsigned long flags; | |
459 | ||
460 | atomic_inc(&cache->stats.discard_count); | |
461 | ||
462 | spin_lock_irqsave(&cache->lock, flags); | |
463 | set_bit(from_dblock(b), cache->discard_bitset); | |
464 | spin_unlock_irqrestore(&cache->lock, flags); | |
465 | } | |
466 | ||
467 | static void clear_discard(struct cache *cache, dm_dblock_t b) | |
468 | { | |
469 | unsigned long flags; | |
470 | ||
471 | spin_lock_irqsave(&cache->lock, flags); | |
472 | clear_bit(from_dblock(b), cache->discard_bitset); | |
473 | spin_unlock_irqrestore(&cache->lock, flags); | |
474 | } | |
475 | ||
476 | static bool is_discarded(struct cache *cache, dm_dblock_t b) | |
477 | { | |
478 | int r; | |
479 | unsigned long flags; | |
480 | ||
481 | spin_lock_irqsave(&cache->lock, flags); | |
482 | r = test_bit(from_dblock(b), cache->discard_bitset); | |
483 | spin_unlock_irqrestore(&cache->lock, flags); | |
484 | ||
485 | return r; | |
486 | } | |
487 | ||
488 | static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) | |
489 | { | |
490 | int r; | |
491 | unsigned long flags; | |
492 | ||
493 | spin_lock_irqsave(&cache->lock, flags); | |
494 | r = test_bit(from_dblock(oblock_to_dblock(cache, b)), | |
495 | cache->discard_bitset); | |
496 | spin_unlock_irqrestore(&cache->lock, flags); | |
497 | ||
498 | return r; | |
499 | } | |
500 | ||
501 | /*----------------------------------------------------------------*/ | |
502 | ||
503 | static void load_stats(struct cache *cache) | |
504 | { | |
505 | struct dm_cache_statistics stats; | |
506 | ||
507 | dm_cache_metadata_get_stats(cache->cmd, &stats); | |
508 | atomic_set(&cache->stats.read_hit, stats.read_hits); | |
509 | atomic_set(&cache->stats.read_miss, stats.read_misses); | |
510 | atomic_set(&cache->stats.write_hit, stats.write_hits); | |
511 | atomic_set(&cache->stats.write_miss, stats.write_misses); | |
512 | } | |
513 | ||
514 | static void save_stats(struct cache *cache) | |
515 | { | |
516 | struct dm_cache_statistics stats; | |
517 | ||
518 | stats.read_hits = atomic_read(&cache->stats.read_hit); | |
519 | stats.read_misses = atomic_read(&cache->stats.read_miss); | |
520 | stats.write_hits = atomic_read(&cache->stats.write_hit); | |
521 | stats.write_misses = atomic_read(&cache->stats.write_miss); | |
522 | ||
523 | dm_cache_metadata_set_stats(cache->cmd, &stats); | |
524 | } | |
525 | ||
526 | /*---------------------------------------------------------------- | |
527 | * Per bio data | |
528 | *--------------------------------------------------------------*/ | |
19b0092e MS |
529 | |
530 | /* | |
531 | * If using writeback, leave out struct per_bio_data's writethrough fields. | |
532 | */ | |
533 | #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) | |
534 | #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) | |
535 | ||
536 | static size_t get_per_bio_data_size(struct cache *cache) | |
537 | { | |
538 | return cache->features.write_through ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; | |
539 | } | |
540 | ||
541 | static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size) | |
c6b4fcba | 542 | { |
19b0092e | 543 | struct per_bio_data *pb = dm_per_bio_data(bio, data_size); |
c6b4fcba JT |
544 | BUG_ON(!pb); |
545 | return pb; | |
546 | } | |
547 | ||
19b0092e | 548 | static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size) |
c6b4fcba | 549 | { |
19b0092e | 550 | struct per_bio_data *pb = get_per_bio_data(bio, data_size); |
c6b4fcba JT |
551 | |
552 | pb->tick = false; | |
553 | pb->req_nr = dm_bio_get_target_bio_nr(bio); | |
554 | pb->all_io_entry = NULL; | |
555 | ||
556 | return pb; | |
557 | } | |
558 | ||
559 | /*---------------------------------------------------------------- | |
560 | * Remapping | |
561 | *--------------------------------------------------------------*/ | |
562 | static void remap_to_origin(struct cache *cache, struct bio *bio) | |
563 | { | |
564 | bio->bi_bdev = cache->origin_dev->bdev; | |
565 | } | |
566 | ||
567 | static void remap_to_cache(struct cache *cache, struct bio *bio, | |
568 | dm_cblock_t cblock) | |
569 | { | |
570 | sector_t bi_sector = bio->bi_sector; | |
571 | ||
572 | bio->bi_bdev = cache->cache_dev->bdev; | |
573 | if (!block_size_is_power_of_two(cache)) | |
574 | bio->bi_sector = (from_cblock(cblock) * cache->sectors_per_block) + | |
575 | sector_div(bi_sector, cache->sectors_per_block); | |
576 | else | |
577 | bio->bi_sector = (from_cblock(cblock) << cache->sectors_per_block_shift) | | |
578 | (bi_sector & (cache->sectors_per_block - 1)); | |
579 | } | |
580 | ||
581 | static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) | |
582 | { | |
583 | unsigned long flags; | |
19b0092e MS |
584 | size_t pb_data_size = get_per_bio_data_size(cache); |
585 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
586 | |
587 | spin_lock_irqsave(&cache->lock, flags); | |
588 | if (cache->need_tick_bio && | |
589 | !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) { | |
590 | pb->tick = true; | |
591 | cache->need_tick_bio = false; | |
592 | } | |
593 | spin_unlock_irqrestore(&cache->lock, flags); | |
594 | } | |
595 | ||
596 | static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, | |
597 | dm_oblock_t oblock) | |
598 | { | |
599 | check_if_tick_bio_needed(cache, bio); | |
600 | remap_to_origin(cache, bio); | |
601 | if (bio_data_dir(bio) == WRITE) | |
602 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | |
603 | } | |
604 | ||
605 | static void remap_to_cache_dirty(struct cache *cache, struct bio *bio, | |
606 | dm_oblock_t oblock, dm_cblock_t cblock) | |
607 | { | |
608 | remap_to_cache(cache, bio, cblock); | |
609 | if (bio_data_dir(bio) == WRITE) { | |
610 | set_dirty(cache, oblock, cblock); | |
611 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | |
612 | } | |
613 | } | |
614 | ||
615 | static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) | |
616 | { | |
617 | sector_t block_nr = bio->bi_sector; | |
618 | ||
619 | if (!block_size_is_power_of_two(cache)) | |
620 | (void) sector_div(block_nr, cache->sectors_per_block); | |
621 | else | |
622 | block_nr >>= cache->sectors_per_block_shift; | |
623 | ||
624 | return to_oblock(block_nr); | |
625 | } | |
626 | ||
627 | static int bio_triggers_commit(struct cache *cache, struct bio *bio) | |
628 | { | |
629 | return bio->bi_rw & (REQ_FLUSH | REQ_FUA); | |
630 | } | |
631 | ||
632 | static void issue(struct cache *cache, struct bio *bio) | |
633 | { | |
634 | unsigned long flags; | |
635 | ||
636 | if (!bio_triggers_commit(cache, bio)) { | |
637 | generic_make_request(bio); | |
638 | return; | |
639 | } | |
640 | ||
641 | /* | |
642 | * Batch together any bios that trigger commits and then issue a | |
643 | * single commit for them in do_worker(). | |
644 | */ | |
645 | spin_lock_irqsave(&cache->lock, flags); | |
646 | cache->commit_requested = true; | |
647 | bio_list_add(&cache->deferred_flush_bios, bio); | |
648 | spin_unlock_irqrestore(&cache->lock, flags); | |
649 | } | |
650 | ||
e2e74d61 JT |
651 | static void defer_writethrough_bio(struct cache *cache, struct bio *bio) |
652 | { | |
653 | unsigned long flags; | |
654 | ||
655 | spin_lock_irqsave(&cache->lock, flags); | |
656 | bio_list_add(&cache->deferred_writethrough_bios, bio); | |
657 | spin_unlock_irqrestore(&cache->lock, flags); | |
658 | ||
659 | wake_worker(cache); | |
660 | } | |
661 | ||
662 | static void writethrough_endio(struct bio *bio, int err) | |
663 | { | |
19b0092e | 664 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
e2e74d61 JT |
665 | bio->bi_end_io = pb->saved_bi_end_io; |
666 | ||
667 | if (err) { | |
668 | bio_endio(bio, err); | |
669 | return; | |
670 | } | |
671 | ||
b844fe69 | 672 | dm_bio_restore(&pb->bio_details, bio); |
e2e74d61 JT |
673 | remap_to_cache(pb->cache, bio, pb->cblock); |
674 | ||
675 | /* | |
676 | * We can't issue this bio directly, since we're in interrupt | |
aeed1420 | 677 | * context. So it gets put on a bio list for processing by the |
e2e74d61 JT |
678 | * worker thread. |
679 | */ | |
680 | defer_writethrough_bio(pb->cache, bio); | |
681 | } | |
682 | ||
683 | /* | |
684 | * When running in writethrough mode we need to send writes to clean blocks | |
685 | * to both the cache and origin devices. In future we'd like to clone the | |
686 | * bio and send them in parallel, but for now we're doing them in | |
687 | * series as this is easier. | |
688 | */ | |
689 | static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, | |
690 | dm_oblock_t oblock, dm_cblock_t cblock) | |
691 | { | |
19b0092e | 692 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
e2e74d61 JT |
693 | |
694 | pb->cache = cache; | |
695 | pb->cblock = cblock; | |
696 | pb->saved_bi_end_io = bio->bi_end_io; | |
b844fe69 | 697 | dm_bio_record(&pb->bio_details, bio); |
e2e74d61 JT |
698 | bio->bi_end_io = writethrough_endio; |
699 | ||
700 | remap_to_origin_clear_discard(pb->cache, bio, oblock); | |
701 | } | |
702 | ||
c6b4fcba JT |
703 | /*---------------------------------------------------------------- |
704 | * Migration processing | |
705 | * | |
706 | * Migration covers moving data from the origin device to the cache, or | |
707 | * vice versa. | |
708 | *--------------------------------------------------------------*/ | |
709 | static void free_migration(struct dm_cache_migration *mg) | |
710 | { | |
711 | mempool_free(mg, mg->cache->migration_pool); | |
712 | } | |
713 | ||
714 | static void inc_nr_migrations(struct cache *cache) | |
715 | { | |
716 | atomic_inc(&cache->nr_migrations); | |
717 | } | |
718 | ||
719 | static void dec_nr_migrations(struct cache *cache) | |
720 | { | |
721 | atomic_dec(&cache->nr_migrations); | |
722 | ||
723 | /* | |
724 | * Wake the worker in case we're suspending the target. | |
725 | */ | |
726 | wake_up(&cache->migration_wait); | |
727 | } | |
728 | ||
729 | static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | |
730 | bool holder) | |
731 | { | |
732 | (holder ? dm_cell_release : dm_cell_release_no_holder) | |
733 | (cache->prison, cell, &cache->deferred_bios); | |
734 | free_prison_cell(cache, cell); | |
735 | } | |
736 | ||
737 | static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | |
738 | bool holder) | |
739 | { | |
740 | unsigned long flags; | |
741 | ||
742 | spin_lock_irqsave(&cache->lock, flags); | |
743 | __cell_defer(cache, cell, holder); | |
744 | spin_unlock_irqrestore(&cache->lock, flags); | |
745 | ||
746 | wake_worker(cache); | |
747 | } | |
748 | ||
749 | static void cleanup_migration(struct dm_cache_migration *mg) | |
750 | { | |
751 | dec_nr_migrations(mg->cache); | |
752 | free_migration(mg); | |
753 | } | |
754 | ||
755 | static void migration_failure(struct dm_cache_migration *mg) | |
756 | { | |
757 | struct cache *cache = mg->cache; | |
758 | ||
759 | if (mg->writeback) { | |
760 | DMWARN_LIMIT("writeback failed; couldn't copy block"); | |
761 | set_dirty(cache, mg->old_oblock, mg->cblock); | |
762 | cell_defer(cache, mg->old_ocell, false); | |
763 | ||
764 | } else if (mg->demote) { | |
765 | DMWARN_LIMIT("demotion failed; couldn't copy block"); | |
766 | policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); | |
767 | ||
768 | cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1); | |
769 | if (mg->promote) | |
770 | cell_defer(cache, mg->new_ocell, 1); | |
771 | } else { | |
772 | DMWARN_LIMIT("promotion failed; couldn't copy block"); | |
773 | policy_remove_mapping(cache->policy, mg->new_oblock); | |
774 | cell_defer(cache, mg->new_ocell, 1); | |
775 | } | |
776 | ||
777 | cleanup_migration(mg); | |
778 | } | |
779 | ||
780 | static void migration_success_pre_commit(struct dm_cache_migration *mg) | |
781 | { | |
782 | unsigned long flags; | |
783 | struct cache *cache = mg->cache; | |
784 | ||
785 | if (mg->writeback) { | |
786 | cell_defer(cache, mg->old_ocell, false); | |
787 | clear_dirty(cache, mg->old_oblock, mg->cblock); | |
788 | cleanup_migration(mg); | |
789 | return; | |
790 | ||
791 | } else if (mg->demote) { | |
792 | if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) { | |
793 | DMWARN_LIMIT("demotion failed; couldn't update on disk metadata"); | |
794 | policy_force_mapping(cache->policy, mg->new_oblock, | |
795 | mg->old_oblock); | |
796 | if (mg->promote) | |
797 | cell_defer(cache, mg->new_ocell, true); | |
798 | cleanup_migration(mg); | |
799 | return; | |
800 | } | |
801 | } else { | |
802 | if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) { | |
803 | DMWARN_LIMIT("promotion failed; couldn't update on disk metadata"); | |
804 | policy_remove_mapping(cache->policy, mg->new_oblock); | |
805 | cleanup_migration(mg); | |
806 | return; | |
807 | } | |
808 | } | |
809 | ||
810 | spin_lock_irqsave(&cache->lock, flags); | |
811 | list_add_tail(&mg->list, &cache->need_commit_migrations); | |
812 | cache->commit_requested = true; | |
813 | spin_unlock_irqrestore(&cache->lock, flags); | |
814 | } | |
815 | ||
816 | static void migration_success_post_commit(struct dm_cache_migration *mg) | |
817 | { | |
818 | unsigned long flags; | |
819 | struct cache *cache = mg->cache; | |
820 | ||
821 | if (mg->writeback) { | |
822 | DMWARN("writeback unexpectedly triggered commit"); | |
823 | return; | |
824 | ||
825 | } else if (mg->demote) { | |
826 | cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1); | |
827 | ||
828 | if (mg->promote) { | |
829 | mg->demote = false; | |
830 | ||
831 | spin_lock_irqsave(&cache->lock, flags); | |
832 | list_add_tail(&mg->list, &cache->quiesced_migrations); | |
833 | spin_unlock_irqrestore(&cache->lock, flags); | |
834 | ||
835 | } else | |
836 | cleanup_migration(mg); | |
837 | ||
838 | } else { | |
839 | cell_defer(cache, mg->new_ocell, true); | |
840 | clear_dirty(cache, mg->new_oblock, mg->cblock); | |
841 | cleanup_migration(mg); | |
842 | } | |
843 | } | |
844 | ||
845 | static void copy_complete(int read_err, unsigned long write_err, void *context) | |
846 | { | |
847 | unsigned long flags; | |
848 | struct dm_cache_migration *mg = (struct dm_cache_migration *) context; | |
849 | struct cache *cache = mg->cache; | |
850 | ||
851 | if (read_err || write_err) | |
852 | mg->err = true; | |
853 | ||
854 | spin_lock_irqsave(&cache->lock, flags); | |
855 | list_add_tail(&mg->list, &cache->completed_migrations); | |
856 | spin_unlock_irqrestore(&cache->lock, flags); | |
857 | ||
858 | wake_worker(cache); | |
859 | } | |
860 | ||
861 | static void issue_copy_real(struct dm_cache_migration *mg) | |
862 | { | |
863 | int r; | |
864 | struct dm_io_region o_region, c_region; | |
865 | struct cache *cache = mg->cache; | |
866 | ||
867 | o_region.bdev = cache->origin_dev->bdev; | |
868 | o_region.count = cache->sectors_per_block; | |
869 | ||
870 | c_region.bdev = cache->cache_dev->bdev; | |
871 | c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block; | |
872 | c_region.count = cache->sectors_per_block; | |
873 | ||
874 | if (mg->writeback || mg->demote) { | |
875 | /* demote */ | |
876 | o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block; | |
877 | r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg); | |
878 | } else { | |
879 | /* promote */ | |
880 | o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block; | |
881 | r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg); | |
882 | } | |
883 | ||
884 | if (r < 0) | |
885 | migration_failure(mg); | |
886 | } | |
887 | ||
888 | static void avoid_copy(struct dm_cache_migration *mg) | |
889 | { | |
890 | atomic_inc(&mg->cache->stats.copies_avoided); | |
891 | migration_success_pre_commit(mg); | |
892 | } | |
893 | ||
894 | static void issue_copy(struct dm_cache_migration *mg) | |
895 | { | |
896 | bool avoid; | |
897 | struct cache *cache = mg->cache; | |
898 | ||
899 | if (mg->writeback || mg->demote) | |
900 | avoid = !is_dirty(cache, mg->cblock) || | |
901 | is_discarded_oblock(cache, mg->old_oblock); | |
902 | else | |
903 | avoid = is_discarded_oblock(cache, mg->new_oblock); | |
904 | ||
905 | avoid ? avoid_copy(mg) : issue_copy_real(mg); | |
906 | } | |
907 | ||
908 | static void complete_migration(struct dm_cache_migration *mg) | |
909 | { | |
910 | if (mg->err) | |
911 | migration_failure(mg); | |
912 | else | |
913 | migration_success_pre_commit(mg); | |
914 | } | |
915 | ||
916 | static void process_migrations(struct cache *cache, struct list_head *head, | |
917 | void (*fn)(struct dm_cache_migration *)) | |
918 | { | |
919 | unsigned long flags; | |
920 | struct list_head list; | |
921 | struct dm_cache_migration *mg, *tmp; | |
922 | ||
923 | INIT_LIST_HEAD(&list); | |
924 | spin_lock_irqsave(&cache->lock, flags); | |
925 | list_splice_init(head, &list); | |
926 | spin_unlock_irqrestore(&cache->lock, flags); | |
927 | ||
928 | list_for_each_entry_safe(mg, tmp, &list, list) | |
929 | fn(mg); | |
930 | } | |
931 | ||
932 | static void __queue_quiesced_migration(struct dm_cache_migration *mg) | |
933 | { | |
934 | list_add_tail(&mg->list, &mg->cache->quiesced_migrations); | |
935 | } | |
936 | ||
937 | static void queue_quiesced_migration(struct dm_cache_migration *mg) | |
938 | { | |
939 | unsigned long flags; | |
940 | struct cache *cache = mg->cache; | |
941 | ||
942 | spin_lock_irqsave(&cache->lock, flags); | |
943 | __queue_quiesced_migration(mg); | |
944 | spin_unlock_irqrestore(&cache->lock, flags); | |
945 | ||
946 | wake_worker(cache); | |
947 | } | |
948 | ||
949 | static void queue_quiesced_migrations(struct cache *cache, struct list_head *work) | |
950 | { | |
951 | unsigned long flags; | |
952 | struct dm_cache_migration *mg, *tmp; | |
953 | ||
954 | spin_lock_irqsave(&cache->lock, flags); | |
955 | list_for_each_entry_safe(mg, tmp, work, list) | |
956 | __queue_quiesced_migration(mg); | |
957 | spin_unlock_irqrestore(&cache->lock, flags); | |
958 | ||
959 | wake_worker(cache); | |
960 | } | |
961 | ||
962 | static void check_for_quiesced_migrations(struct cache *cache, | |
963 | struct per_bio_data *pb) | |
964 | { | |
965 | struct list_head work; | |
966 | ||
967 | if (!pb->all_io_entry) | |
968 | return; | |
969 | ||
970 | INIT_LIST_HEAD(&work); | |
971 | if (pb->all_io_entry) | |
972 | dm_deferred_entry_dec(pb->all_io_entry, &work); | |
973 | ||
974 | if (!list_empty(&work)) | |
975 | queue_quiesced_migrations(cache, &work); | |
976 | } | |
977 | ||
978 | static void quiesce_migration(struct dm_cache_migration *mg) | |
979 | { | |
980 | if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list)) | |
981 | queue_quiesced_migration(mg); | |
982 | } | |
983 | ||
984 | static void promote(struct cache *cache, struct prealloc *structs, | |
985 | dm_oblock_t oblock, dm_cblock_t cblock, | |
986 | struct dm_bio_prison_cell *cell) | |
987 | { | |
988 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
989 | ||
990 | mg->err = false; | |
991 | mg->writeback = false; | |
992 | mg->demote = false; | |
993 | mg->promote = true; | |
994 | mg->cache = cache; | |
995 | mg->new_oblock = oblock; | |
996 | mg->cblock = cblock; | |
997 | mg->old_ocell = NULL; | |
998 | mg->new_ocell = cell; | |
999 | mg->start_jiffies = jiffies; | |
1000 | ||
1001 | inc_nr_migrations(cache); | |
1002 | quiesce_migration(mg); | |
1003 | } | |
1004 | ||
1005 | static void writeback(struct cache *cache, struct prealloc *structs, | |
1006 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1007 | struct dm_bio_prison_cell *cell) | |
1008 | { | |
1009 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1010 | ||
1011 | mg->err = false; | |
1012 | mg->writeback = true; | |
1013 | mg->demote = false; | |
1014 | mg->promote = false; | |
1015 | mg->cache = cache; | |
1016 | mg->old_oblock = oblock; | |
1017 | mg->cblock = cblock; | |
1018 | mg->old_ocell = cell; | |
1019 | mg->new_ocell = NULL; | |
1020 | mg->start_jiffies = jiffies; | |
1021 | ||
1022 | inc_nr_migrations(cache); | |
1023 | quiesce_migration(mg); | |
1024 | } | |
1025 | ||
1026 | static void demote_then_promote(struct cache *cache, struct prealloc *structs, | |
1027 | dm_oblock_t old_oblock, dm_oblock_t new_oblock, | |
1028 | dm_cblock_t cblock, | |
1029 | struct dm_bio_prison_cell *old_ocell, | |
1030 | struct dm_bio_prison_cell *new_ocell) | |
1031 | { | |
1032 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1033 | ||
1034 | mg->err = false; | |
1035 | mg->writeback = false; | |
1036 | mg->demote = true; | |
1037 | mg->promote = true; | |
1038 | mg->cache = cache; | |
1039 | mg->old_oblock = old_oblock; | |
1040 | mg->new_oblock = new_oblock; | |
1041 | mg->cblock = cblock; | |
1042 | mg->old_ocell = old_ocell; | |
1043 | mg->new_ocell = new_ocell; | |
1044 | mg->start_jiffies = jiffies; | |
1045 | ||
1046 | inc_nr_migrations(cache); | |
1047 | quiesce_migration(mg); | |
1048 | } | |
1049 | ||
1050 | /*---------------------------------------------------------------- | |
1051 | * bio processing | |
1052 | *--------------------------------------------------------------*/ | |
1053 | static void defer_bio(struct cache *cache, struct bio *bio) | |
1054 | { | |
1055 | unsigned long flags; | |
1056 | ||
1057 | spin_lock_irqsave(&cache->lock, flags); | |
1058 | bio_list_add(&cache->deferred_bios, bio); | |
1059 | spin_unlock_irqrestore(&cache->lock, flags); | |
1060 | ||
1061 | wake_worker(cache); | |
1062 | } | |
1063 | ||
1064 | static void process_flush_bio(struct cache *cache, struct bio *bio) | |
1065 | { | |
19b0092e MS |
1066 | size_t pb_data_size = get_per_bio_data_size(cache); |
1067 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
1068 | |
1069 | BUG_ON(bio->bi_size); | |
1070 | if (!pb->req_nr) | |
1071 | remap_to_origin(cache, bio); | |
1072 | else | |
1073 | remap_to_cache(cache, bio, 0); | |
1074 | ||
1075 | issue(cache, bio); | |
1076 | } | |
1077 | ||
1078 | /* | |
1079 | * People generally discard large parts of a device, eg, the whole device | |
1080 | * when formatting. Splitting these large discards up into cache block | |
1081 | * sized ios and then quiescing (always neccessary for discard) takes too | |
1082 | * long. | |
1083 | * | |
1084 | * We keep it simple, and allow any size of discard to come in, and just | |
1085 | * mark off blocks on the discard bitset. No passdown occurs! | |
1086 | * | |
1087 | * To implement passdown we need to change the bio_prison such that a cell | |
1088 | * can have a key that spans many blocks. | |
1089 | */ | |
1090 | static void process_discard_bio(struct cache *cache, struct bio *bio) | |
1091 | { | |
1092 | dm_block_t start_block = dm_sector_div_up(bio->bi_sector, | |
1093 | cache->discard_block_size); | |
1094 | dm_block_t end_block = bio->bi_sector + bio_sectors(bio); | |
1095 | dm_block_t b; | |
1096 | ||
414dd67d | 1097 | end_block = block_div(end_block, cache->discard_block_size); |
c6b4fcba JT |
1098 | |
1099 | for (b = start_block; b < end_block; b++) | |
1100 | set_discard(cache, to_dblock(b)); | |
1101 | ||
1102 | bio_endio(bio, 0); | |
1103 | } | |
1104 | ||
1105 | static bool spare_migration_bandwidth(struct cache *cache) | |
1106 | { | |
1107 | sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) * | |
1108 | cache->sectors_per_block; | |
1109 | return current_volume < cache->migration_threshold; | |
1110 | } | |
1111 | ||
1112 | static bool is_writethrough_io(struct cache *cache, struct bio *bio, | |
1113 | dm_cblock_t cblock) | |
1114 | { | |
1115 | return bio_data_dir(bio) == WRITE && | |
1116 | cache->features.write_through && !is_dirty(cache, cblock); | |
1117 | } | |
1118 | ||
1119 | static void inc_hit_counter(struct cache *cache, struct bio *bio) | |
1120 | { | |
1121 | atomic_inc(bio_data_dir(bio) == READ ? | |
1122 | &cache->stats.read_hit : &cache->stats.write_hit); | |
1123 | } | |
1124 | ||
1125 | static void inc_miss_counter(struct cache *cache, struct bio *bio) | |
1126 | { | |
1127 | atomic_inc(bio_data_dir(bio) == READ ? | |
1128 | &cache->stats.read_miss : &cache->stats.write_miss); | |
1129 | } | |
1130 | ||
1131 | static void process_bio(struct cache *cache, struct prealloc *structs, | |
1132 | struct bio *bio) | |
1133 | { | |
1134 | int r; | |
1135 | bool release_cell = true; | |
1136 | dm_oblock_t block = get_bio_block(cache, bio); | |
1137 | struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell; | |
1138 | struct policy_result lookup_result; | |
19b0092e MS |
1139 | size_t pb_data_size = get_per_bio_data_size(cache); |
1140 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
1141 | bool discarded_block = is_discarded_oblock(cache, block); |
1142 | bool can_migrate = discarded_block || spare_migration_bandwidth(cache); | |
1143 | ||
1144 | /* | |
1145 | * Check to see if that block is currently migrating. | |
1146 | */ | |
1147 | cell_prealloc = prealloc_get_cell(structs); | |
1148 | r = bio_detain(cache, block, bio, cell_prealloc, | |
1149 | (cell_free_fn) prealloc_put_cell, | |
1150 | structs, &new_ocell); | |
1151 | if (r > 0) | |
1152 | return; | |
1153 | ||
1154 | r = policy_map(cache->policy, block, true, can_migrate, discarded_block, | |
1155 | bio, &lookup_result); | |
1156 | ||
1157 | if (r == -EWOULDBLOCK) | |
1158 | /* migration has been denied */ | |
1159 | lookup_result.op = POLICY_MISS; | |
1160 | ||
1161 | switch (lookup_result.op) { | |
1162 | case POLICY_HIT: | |
1163 | inc_hit_counter(cache, bio); | |
1164 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
1165 | ||
e2e74d61 JT |
1166 | if (is_writethrough_io(cache, bio, lookup_result.cblock)) |
1167 | remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); | |
1168 | else | |
c6b4fcba JT |
1169 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); |
1170 | ||
1171 | issue(cache, bio); | |
1172 | break; | |
1173 | ||
1174 | case POLICY_MISS: | |
1175 | inc_miss_counter(cache, bio); | |
1176 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
e2e74d61 JT |
1177 | remap_to_origin_clear_discard(cache, bio, block); |
1178 | issue(cache, bio); | |
c6b4fcba JT |
1179 | break; |
1180 | ||
1181 | case POLICY_NEW: | |
1182 | atomic_inc(&cache->stats.promotion); | |
1183 | promote(cache, structs, block, lookup_result.cblock, new_ocell); | |
1184 | release_cell = false; | |
1185 | break; | |
1186 | ||
1187 | case POLICY_REPLACE: | |
1188 | cell_prealloc = prealloc_get_cell(structs); | |
1189 | r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc, | |
1190 | (cell_free_fn) prealloc_put_cell, | |
1191 | structs, &old_ocell); | |
1192 | if (r > 0) { | |
1193 | /* | |
1194 | * We have to be careful to avoid lock inversion of | |
1195 | * the cells. So we back off, and wait for the | |
1196 | * old_ocell to become free. | |
1197 | */ | |
1198 | policy_force_mapping(cache->policy, block, | |
1199 | lookup_result.old_oblock); | |
1200 | atomic_inc(&cache->stats.cache_cell_clash); | |
1201 | break; | |
1202 | } | |
1203 | atomic_inc(&cache->stats.demotion); | |
1204 | atomic_inc(&cache->stats.promotion); | |
1205 | ||
1206 | demote_then_promote(cache, structs, lookup_result.old_oblock, | |
1207 | block, lookup_result.cblock, | |
1208 | old_ocell, new_ocell); | |
1209 | release_cell = false; | |
1210 | break; | |
1211 | ||
1212 | default: | |
1213 | DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__, | |
1214 | (unsigned) lookup_result.op); | |
1215 | bio_io_error(bio); | |
1216 | } | |
1217 | ||
1218 | if (release_cell) | |
1219 | cell_defer(cache, new_ocell, false); | |
1220 | } | |
1221 | ||
1222 | static int need_commit_due_to_time(struct cache *cache) | |
1223 | { | |
1224 | return jiffies < cache->last_commit_jiffies || | |
1225 | jiffies > cache->last_commit_jiffies + COMMIT_PERIOD; | |
1226 | } | |
1227 | ||
1228 | static int commit_if_needed(struct cache *cache) | |
1229 | { | |
1230 | if (dm_cache_changed_this_transaction(cache->cmd) && | |
1231 | (cache->commit_requested || need_commit_due_to_time(cache))) { | |
1232 | atomic_inc(&cache->stats.commit_count); | |
1233 | cache->last_commit_jiffies = jiffies; | |
1234 | cache->commit_requested = false; | |
1235 | return dm_cache_commit(cache->cmd, false); | |
1236 | } | |
1237 | ||
1238 | return 0; | |
1239 | } | |
1240 | ||
1241 | static void process_deferred_bios(struct cache *cache) | |
1242 | { | |
1243 | unsigned long flags; | |
1244 | struct bio_list bios; | |
1245 | struct bio *bio; | |
1246 | struct prealloc structs; | |
1247 | ||
1248 | memset(&structs, 0, sizeof(structs)); | |
1249 | bio_list_init(&bios); | |
1250 | ||
1251 | spin_lock_irqsave(&cache->lock, flags); | |
1252 | bio_list_merge(&bios, &cache->deferred_bios); | |
1253 | bio_list_init(&cache->deferred_bios); | |
1254 | spin_unlock_irqrestore(&cache->lock, flags); | |
1255 | ||
1256 | while (!bio_list_empty(&bios)) { | |
1257 | /* | |
1258 | * If we've got no free migration structs, and processing | |
1259 | * this bio might require one, we pause until there are some | |
1260 | * prepared mappings to process. | |
1261 | */ | |
1262 | if (prealloc_data_structs(cache, &structs)) { | |
1263 | spin_lock_irqsave(&cache->lock, flags); | |
1264 | bio_list_merge(&cache->deferred_bios, &bios); | |
1265 | spin_unlock_irqrestore(&cache->lock, flags); | |
1266 | break; | |
1267 | } | |
1268 | ||
1269 | bio = bio_list_pop(&bios); | |
1270 | ||
1271 | if (bio->bi_rw & REQ_FLUSH) | |
1272 | process_flush_bio(cache, bio); | |
1273 | else if (bio->bi_rw & REQ_DISCARD) | |
1274 | process_discard_bio(cache, bio); | |
1275 | else | |
1276 | process_bio(cache, &structs, bio); | |
1277 | } | |
1278 | ||
1279 | prealloc_free_structs(cache, &structs); | |
1280 | } | |
1281 | ||
1282 | static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) | |
1283 | { | |
1284 | unsigned long flags; | |
1285 | struct bio_list bios; | |
1286 | struct bio *bio; | |
1287 | ||
1288 | bio_list_init(&bios); | |
1289 | ||
1290 | spin_lock_irqsave(&cache->lock, flags); | |
1291 | bio_list_merge(&bios, &cache->deferred_flush_bios); | |
1292 | bio_list_init(&cache->deferred_flush_bios); | |
1293 | spin_unlock_irqrestore(&cache->lock, flags); | |
1294 | ||
1295 | while ((bio = bio_list_pop(&bios))) | |
1296 | submit_bios ? generic_make_request(bio) : bio_io_error(bio); | |
1297 | } | |
1298 | ||
e2e74d61 JT |
1299 | static void process_deferred_writethrough_bios(struct cache *cache) |
1300 | { | |
1301 | unsigned long flags; | |
1302 | struct bio_list bios; | |
1303 | struct bio *bio; | |
1304 | ||
1305 | bio_list_init(&bios); | |
1306 | ||
1307 | spin_lock_irqsave(&cache->lock, flags); | |
1308 | bio_list_merge(&bios, &cache->deferred_writethrough_bios); | |
1309 | bio_list_init(&cache->deferred_writethrough_bios); | |
1310 | spin_unlock_irqrestore(&cache->lock, flags); | |
1311 | ||
1312 | while ((bio = bio_list_pop(&bios))) | |
1313 | generic_make_request(bio); | |
1314 | } | |
1315 | ||
c6b4fcba JT |
1316 | static void writeback_some_dirty_blocks(struct cache *cache) |
1317 | { | |
1318 | int r = 0; | |
1319 | dm_oblock_t oblock; | |
1320 | dm_cblock_t cblock; | |
1321 | struct prealloc structs; | |
1322 | struct dm_bio_prison_cell *old_ocell; | |
1323 | ||
1324 | memset(&structs, 0, sizeof(structs)); | |
1325 | ||
1326 | while (spare_migration_bandwidth(cache)) { | |
1327 | if (prealloc_data_structs(cache, &structs)) | |
1328 | break; | |
1329 | ||
1330 | r = policy_writeback_work(cache->policy, &oblock, &cblock); | |
1331 | if (r) | |
1332 | break; | |
1333 | ||
1334 | r = get_cell(cache, oblock, &structs, &old_ocell); | |
1335 | if (r) { | |
1336 | policy_set_dirty(cache->policy, oblock); | |
1337 | break; | |
1338 | } | |
1339 | ||
1340 | writeback(cache, &structs, oblock, cblock, old_ocell); | |
1341 | } | |
1342 | ||
1343 | prealloc_free_structs(cache, &structs); | |
1344 | } | |
1345 | ||
1346 | /*---------------------------------------------------------------- | |
1347 | * Main worker loop | |
1348 | *--------------------------------------------------------------*/ | |
1349 | static void start_quiescing(struct cache *cache) | |
1350 | { | |
1351 | unsigned long flags; | |
1352 | ||
1353 | spin_lock_irqsave(&cache->lock, flags); | |
1354 | cache->quiescing = 1; | |
1355 | spin_unlock_irqrestore(&cache->lock, flags); | |
1356 | } | |
1357 | ||
1358 | static void stop_quiescing(struct cache *cache) | |
1359 | { | |
1360 | unsigned long flags; | |
1361 | ||
1362 | spin_lock_irqsave(&cache->lock, flags); | |
1363 | cache->quiescing = 0; | |
1364 | spin_unlock_irqrestore(&cache->lock, flags); | |
1365 | } | |
1366 | ||
1367 | static bool is_quiescing(struct cache *cache) | |
1368 | { | |
1369 | int r; | |
1370 | unsigned long flags; | |
1371 | ||
1372 | spin_lock_irqsave(&cache->lock, flags); | |
1373 | r = cache->quiescing; | |
1374 | spin_unlock_irqrestore(&cache->lock, flags); | |
1375 | ||
1376 | return r; | |
1377 | } | |
1378 | ||
1379 | static void wait_for_migrations(struct cache *cache) | |
1380 | { | |
1381 | wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations)); | |
1382 | } | |
1383 | ||
1384 | static void stop_worker(struct cache *cache) | |
1385 | { | |
1386 | cancel_delayed_work(&cache->waker); | |
1387 | flush_workqueue(cache->wq); | |
1388 | } | |
1389 | ||
1390 | static void requeue_deferred_io(struct cache *cache) | |
1391 | { | |
1392 | struct bio *bio; | |
1393 | struct bio_list bios; | |
1394 | ||
1395 | bio_list_init(&bios); | |
1396 | bio_list_merge(&bios, &cache->deferred_bios); | |
1397 | bio_list_init(&cache->deferred_bios); | |
1398 | ||
1399 | while ((bio = bio_list_pop(&bios))) | |
1400 | bio_endio(bio, DM_ENDIO_REQUEUE); | |
1401 | } | |
1402 | ||
1403 | static int more_work(struct cache *cache) | |
1404 | { | |
1405 | if (is_quiescing(cache)) | |
1406 | return !list_empty(&cache->quiesced_migrations) || | |
1407 | !list_empty(&cache->completed_migrations) || | |
1408 | !list_empty(&cache->need_commit_migrations); | |
1409 | else | |
1410 | return !bio_list_empty(&cache->deferred_bios) || | |
1411 | !bio_list_empty(&cache->deferred_flush_bios) || | |
e2e74d61 | 1412 | !bio_list_empty(&cache->deferred_writethrough_bios) || |
c6b4fcba JT |
1413 | !list_empty(&cache->quiesced_migrations) || |
1414 | !list_empty(&cache->completed_migrations) || | |
1415 | !list_empty(&cache->need_commit_migrations); | |
1416 | } | |
1417 | ||
1418 | static void do_worker(struct work_struct *ws) | |
1419 | { | |
1420 | struct cache *cache = container_of(ws, struct cache, worker); | |
1421 | ||
1422 | do { | |
1423 | if (!is_quiescing(cache)) | |
1424 | process_deferred_bios(cache); | |
1425 | ||
1426 | process_migrations(cache, &cache->quiesced_migrations, issue_copy); | |
1427 | process_migrations(cache, &cache->completed_migrations, complete_migration); | |
1428 | ||
1429 | writeback_some_dirty_blocks(cache); | |
1430 | ||
e2e74d61 JT |
1431 | process_deferred_writethrough_bios(cache); |
1432 | ||
c6b4fcba JT |
1433 | if (commit_if_needed(cache)) { |
1434 | process_deferred_flush_bios(cache, false); | |
1435 | ||
1436 | /* | |
1437 | * FIXME: rollback metadata or just go into a | |
1438 | * failure mode and error everything | |
1439 | */ | |
1440 | } else { | |
1441 | process_deferred_flush_bios(cache, true); | |
1442 | process_migrations(cache, &cache->need_commit_migrations, | |
1443 | migration_success_post_commit); | |
1444 | } | |
1445 | } while (more_work(cache)); | |
1446 | } | |
1447 | ||
1448 | /* | |
1449 | * We want to commit periodically so that not too much | |
1450 | * unwritten metadata builds up. | |
1451 | */ | |
1452 | static void do_waker(struct work_struct *ws) | |
1453 | { | |
1454 | struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker); | |
f8350daf | 1455 | policy_tick(cache->policy); |
c6b4fcba JT |
1456 | wake_worker(cache); |
1457 | queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); | |
1458 | } | |
1459 | ||
1460 | /*----------------------------------------------------------------*/ | |
1461 | ||
1462 | static int is_congested(struct dm_dev *dev, int bdi_bits) | |
1463 | { | |
1464 | struct request_queue *q = bdev_get_queue(dev->bdev); | |
1465 | return bdi_congested(&q->backing_dev_info, bdi_bits); | |
1466 | } | |
1467 | ||
1468 | static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits) | |
1469 | { | |
1470 | struct cache *cache = container_of(cb, struct cache, callbacks); | |
1471 | ||
1472 | return is_congested(cache->origin_dev, bdi_bits) || | |
1473 | is_congested(cache->cache_dev, bdi_bits); | |
1474 | } | |
1475 | ||
1476 | /*---------------------------------------------------------------- | |
1477 | * Target methods | |
1478 | *--------------------------------------------------------------*/ | |
1479 | ||
1480 | /* | |
1481 | * This function gets called on the error paths of the constructor, so we | |
1482 | * have to cope with a partially initialised struct. | |
1483 | */ | |
1484 | static void destroy(struct cache *cache) | |
1485 | { | |
1486 | unsigned i; | |
1487 | ||
1488 | if (cache->next_migration) | |
1489 | mempool_free(cache->next_migration, cache->migration_pool); | |
1490 | ||
1491 | if (cache->migration_pool) | |
1492 | mempool_destroy(cache->migration_pool); | |
1493 | ||
1494 | if (cache->all_io_ds) | |
1495 | dm_deferred_set_destroy(cache->all_io_ds); | |
1496 | ||
1497 | if (cache->prison) | |
1498 | dm_bio_prison_destroy(cache->prison); | |
1499 | ||
1500 | if (cache->wq) | |
1501 | destroy_workqueue(cache->wq); | |
1502 | ||
1503 | if (cache->dirty_bitset) | |
1504 | free_bitset(cache->dirty_bitset); | |
1505 | ||
1506 | if (cache->discard_bitset) | |
1507 | free_bitset(cache->discard_bitset); | |
1508 | ||
1509 | if (cache->copier) | |
1510 | dm_kcopyd_client_destroy(cache->copier); | |
1511 | ||
1512 | if (cache->cmd) | |
1513 | dm_cache_metadata_close(cache->cmd); | |
1514 | ||
1515 | if (cache->metadata_dev) | |
1516 | dm_put_device(cache->ti, cache->metadata_dev); | |
1517 | ||
1518 | if (cache->origin_dev) | |
1519 | dm_put_device(cache->ti, cache->origin_dev); | |
1520 | ||
1521 | if (cache->cache_dev) | |
1522 | dm_put_device(cache->ti, cache->cache_dev); | |
1523 | ||
1524 | if (cache->policy) | |
1525 | dm_cache_policy_destroy(cache->policy); | |
1526 | ||
1527 | for (i = 0; i < cache->nr_ctr_args ; i++) | |
1528 | kfree(cache->ctr_args[i]); | |
1529 | kfree(cache->ctr_args); | |
1530 | ||
1531 | kfree(cache); | |
1532 | } | |
1533 | ||
1534 | static void cache_dtr(struct dm_target *ti) | |
1535 | { | |
1536 | struct cache *cache = ti->private; | |
1537 | ||
1538 | destroy(cache); | |
1539 | } | |
1540 | ||
1541 | static sector_t get_dev_size(struct dm_dev *dev) | |
1542 | { | |
1543 | return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT; | |
1544 | } | |
1545 | ||
1546 | /*----------------------------------------------------------------*/ | |
1547 | ||
1548 | /* | |
1549 | * Construct a cache device mapping. | |
1550 | * | |
1551 | * cache <metadata dev> <cache dev> <origin dev> <block size> | |
1552 | * <#feature args> [<feature arg>]* | |
1553 | * <policy> <#policy args> [<policy arg>]* | |
1554 | * | |
1555 | * metadata dev : fast device holding the persistent metadata | |
1556 | * cache dev : fast device holding cached data blocks | |
1557 | * origin dev : slow device holding original data blocks | |
1558 | * block size : cache unit size in sectors | |
1559 | * | |
1560 | * #feature args : number of feature arguments passed | |
1561 | * feature args : writethrough. (The default is writeback.) | |
1562 | * | |
1563 | * policy : the replacement policy to use | |
1564 | * #policy args : an even number of policy arguments corresponding | |
1565 | * to key/value pairs passed to the policy | |
1566 | * policy args : key/value pairs passed to the policy | |
1567 | * E.g. 'sequential_threshold 1024' | |
1568 | * See cache-policies.txt for details. | |
1569 | * | |
1570 | * Optional feature arguments are: | |
1571 | * writethrough : write through caching that prohibits cache block | |
1572 | * content from being different from origin block content. | |
1573 | * Without this argument, the default behaviour is to write | |
1574 | * back cache block contents later for performance reasons, | |
1575 | * so they may differ from the corresponding origin blocks. | |
1576 | */ | |
1577 | struct cache_args { | |
1578 | struct dm_target *ti; | |
1579 | ||
1580 | struct dm_dev *metadata_dev; | |
1581 | ||
1582 | struct dm_dev *cache_dev; | |
1583 | sector_t cache_sectors; | |
1584 | ||
1585 | struct dm_dev *origin_dev; | |
1586 | sector_t origin_sectors; | |
1587 | ||
1588 | uint32_t block_size; | |
1589 | ||
1590 | const char *policy_name; | |
1591 | int policy_argc; | |
1592 | const char **policy_argv; | |
1593 | ||
1594 | struct cache_features features; | |
1595 | }; | |
1596 | ||
1597 | static void destroy_cache_args(struct cache_args *ca) | |
1598 | { | |
1599 | if (ca->metadata_dev) | |
1600 | dm_put_device(ca->ti, ca->metadata_dev); | |
1601 | ||
1602 | if (ca->cache_dev) | |
1603 | dm_put_device(ca->ti, ca->cache_dev); | |
1604 | ||
1605 | if (ca->origin_dev) | |
1606 | dm_put_device(ca->ti, ca->origin_dev); | |
1607 | ||
1608 | kfree(ca); | |
1609 | } | |
1610 | ||
1611 | static bool at_least_one_arg(struct dm_arg_set *as, char **error) | |
1612 | { | |
1613 | if (!as->argc) { | |
1614 | *error = "Insufficient args"; | |
1615 | return false; | |
1616 | } | |
1617 | ||
1618 | return true; | |
1619 | } | |
1620 | ||
1621 | static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1622 | char **error) | |
1623 | { | |
1624 | int r; | |
1625 | sector_t metadata_dev_size; | |
1626 | char b[BDEVNAME_SIZE]; | |
1627 | ||
1628 | if (!at_least_one_arg(as, error)) | |
1629 | return -EINVAL; | |
1630 | ||
1631 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1632 | &ca->metadata_dev); | |
1633 | if (r) { | |
1634 | *error = "Error opening metadata device"; | |
1635 | return r; | |
1636 | } | |
1637 | ||
1638 | metadata_dev_size = get_dev_size(ca->metadata_dev); | |
1639 | if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING) | |
1640 | DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", | |
1641 | bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS); | |
1642 | ||
1643 | return 0; | |
1644 | } | |
1645 | ||
1646 | static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1647 | char **error) | |
1648 | { | |
1649 | int r; | |
1650 | ||
1651 | if (!at_least_one_arg(as, error)) | |
1652 | return -EINVAL; | |
1653 | ||
1654 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1655 | &ca->cache_dev); | |
1656 | if (r) { | |
1657 | *error = "Error opening cache device"; | |
1658 | return r; | |
1659 | } | |
1660 | ca->cache_sectors = get_dev_size(ca->cache_dev); | |
1661 | ||
1662 | return 0; | |
1663 | } | |
1664 | ||
1665 | static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1666 | char **error) | |
1667 | { | |
1668 | int r; | |
1669 | ||
1670 | if (!at_least_one_arg(as, error)) | |
1671 | return -EINVAL; | |
1672 | ||
1673 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1674 | &ca->origin_dev); | |
1675 | if (r) { | |
1676 | *error = "Error opening origin device"; | |
1677 | return r; | |
1678 | } | |
1679 | ||
1680 | ca->origin_sectors = get_dev_size(ca->origin_dev); | |
1681 | if (ca->ti->len > ca->origin_sectors) { | |
1682 | *error = "Device size larger than cached device"; | |
1683 | return -EINVAL; | |
1684 | } | |
1685 | ||
1686 | return 0; | |
1687 | } | |
1688 | ||
1689 | static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, | |
1690 | char **error) | |
1691 | { | |
05473044 | 1692 | unsigned long block_size; |
c6b4fcba JT |
1693 | |
1694 | if (!at_least_one_arg(as, error)) | |
1695 | return -EINVAL; | |
1696 | ||
05473044 MS |
1697 | if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size || |
1698 | block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || | |
1699 | block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || | |
1700 | block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { | |
c6b4fcba JT |
1701 | *error = "Invalid data block size"; |
1702 | return -EINVAL; | |
1703 | } | |
1704 | ||
05473044 | 1705 | if (block_size > ca->cache_sectors) { |
c6b4fcba JT |
1706 | *error = "Data block size is larger than the cache device"; |
1707 | return -EINVAL; | |
1708 | } | |
1709 | ||
05473044 | 1710 | ca->block_size = block_size; |
c6b4fcba JT |
1711 | |
1712 | return 0; | |
1713 | } | |
1714 | ||
1715 | static void init_features(struct cache_features *cf) | |
1716 | { | |
1717 | cf->mode = CM_WRITE; | |
1718 | cf->write_through = false; | |
1719 | } | |
1720 | ||
1721 | static int parse_features(struct cache_args *ca, struct dm_arg_set *as, | |
1722 | char **error) | |
1723 | { | |
1724 | static struct dm_arg _args[] = { | |
1725 | {0, 1, "Invalid number of cache feature arguments"}, | |
1726 | }; | |
1727 | ||
1728 | int r; | |
1729 | unsigned argc; | |
1730 | const char *arg; | |
1731 | struct cache_features *cf = &ca->features; | |
1732 | ||
1733 | init_features(cf); | |
1734 | ||
1735 | r = dm_read_arg_group(_args, as, &argc, error); | |
1736 | if (r) | |
1737 | return -EINVAL; | |
1738 | ||
1739 | while (argc--) { | |
1740 | arg = dm_shift_arg(as); | |
1741 | ||
1742 | if (!strcasecmp(arg, "writeback")) | |
1743 | cf->write_through = false; | |
1744 | ||
1745 | else if (!strcasecmp(arg, "writethrough")) | |
1746 | cf->write_through = true; | |
1747 | ||
1748 | else { | |
1749 | *error = "Unrecognised cache feature requested"; | |
1750 | return -EINVAL; | |
1751 | } | |
1752 | } | |
1753 | ||
1754 | return 0; | |
1755 | } | |
1756 | ||
1757 | static int parse_policy(struct cache_args *ca, struct dm_arg_set *as, | |
1758 | char **error) | |
1759 | { | |
1760 | static struct dm_arg _args[] = { | |
1761 | {0, 1024, "Invalid number of policy arguments"}, | |
1762 | }; | |
1763 | ||
1764 | int r; | |
1765 | ||
1766 | if (!at_least_one_arg(as, error)) | |
1767 | return -EINVAL; | |
1768 | ||
1769 | ca->policy_name = dm_shift_arg(as); | |
1770 | ||
1771 | r = dm_read_arg_group(_args, as, &ca->policy_argc, error); | |
1772 | if (r) | |
1773 | return -EINVAL; | |
1774 | ||
1775 | ca->policy_argv = (const char **)as->argv; | |
1776 | dm_consume_args(as, ca->policy_argc); | |
1777 | ||
1778 | return 0; | |
1779 | } | |
1780 | ||
1781 | static int parse_cache_args(struct cache_args *ca, int argc, char **argv, | |
1782 | char **error) | |
1783 | { | |
1784 | int r; | |
1785 | struct dm_arg_set as; | |
1786 | ||
1787 | as.argc = argc; | |
1788 | as.argv = argv; | |
1789 | ||
1790 | r = parse_metadata_dev(ca, &as, error); | |
1791 | if (r) | |
1792 | return r; | |
1793 | ||
1794 | r = parse_cache_dev(ca, &as, error); | |
1795 | if (r) | |
1796 | return r; | |
1797 | ||
1798 | r = parse_origin_dev(ca, &as, error); | |
1799 | if (r) | |
1800 | return r; | |
1801 | ||
1802 | r = parse_block_size(ca, &as, error); | |
1803 | if (r) | |
1804 | return r; | |
1805 | ||
1806 | r = parse_features(ca, &as, error); | |
1807 | if (r) | |
1808 | return r; | |
1809 | ||
1810 | r = parse_policy(ca, &as, error); | |
1811 | if (r) | |
1812 | return r; | |
1813 | ||
1814 | return 0; | |
1815 | } | |
1816 | ||
1817 | /*----------------------------------------------------------------*/ | |
1818 | ||
1819 | static struct kmem_cache *migration_cache; | |
1820 | ||
2c73c471 AK |
1821 | #define NOT_CORE_OPTION 1 |
1822 | ||
2f14f4b5 | 1823 | static int process_config_option(struct cache *cache, const char *key, const char *value) |
2c73c471 AK |
1824 | { |
1825 | unsigned long tmp; | |
1826 | ||
2f14f4b5 JT |
1827 | if (!strcasecmp(key, "migration_threshold")) { |
1828 | if (kstrtoul(value, 10, &tmp)) | |
2c73c471 AK |
1829 | return -EINVAL; |
1830 | ||
1831 | cache->migration_threshold = tmp; | |
1832 | return 0; | |
1833 | } | |
1834 | ||
1835 | return NOT_CORE_OPTION; | |
1836 | } | |
1837 | ||
2f14f4b5 JT |
1838 | static int set_config_value(struct cache *cache, const char *key, const char *value) |
1839 | { | |
1840 | int r = process_config_option(cache, key, value); | |
1841 | ||
1842 | if (r == NOT_CORE_OPTION) | |
1843 | r = policy_set_config_value(cache->policy, key, value); | |
1844 | ||
1845 | if (r) | |
1846 | DMWARN("bad config value for %s: %s", key, value); | |
1847 | ||
1848 | return r; | |
1849 | } | |
1850 | ||
1851 | static int set_config_values(struct cache *cache, int argc, const char **argv) | |
c6b4fcba JT |
1852 | { |
1853 | int r = 0; | |
1854 | ||
1855 | if (argc & 1) { | |
1856 | DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs."); | |
1857 | return -EINVAL; | |
1858 | } | |
1859 | ||
1860 | while (argc) { | |
2f14f4b5 JT |
1861 | r = set_config_value(cache, argv[0], argv[1]); |
1862 | if (r) | |
1863 | break; | |
c6b4fcba JT |
1864 | |
1865 | argc -= 2; | |
1866 | argv += 2; | |
1867 | } | |
1868 | ||
1869 | return r; | |
1870 | } | |
1871 | ||
1872 | static int create_cache_policy(struct cache *cache, struct cache_args *ca, | |
1873 | char **error) | |
1874 | { | |
c6b4fcba JT |
1875 | cache->policy = dm_cache_policy_create(ca->policy_name, |
1876 | cache->cache_size, | |
1877 | cache->origin_sectors, | |
1878 | cache->sectors_per_block); | |
1879 | if (!cache->policy) { | |
1880 | *error = "Error creating cache's policy"; | |
1881 | return -ENOMEM; | |
1882 | } | |
1883 | ||
2f14f4b5 | 1884 | return 0; |
c6b4fcba JT |
1885 | } |
1886 | ||
1887 | /* | |
1888 | * We want the discard block size to be a power of two, at least the size | |
1889 | * of the cache block size, and have no more than 2^14 discard blocks | |
1890 | * across the origin. | |
1891 | */ | |
1892 | #define MAX_DISCARD_BLOCKS (1 << 14) | |
1893 | ||
1894 | static bool too_many_discard_blocks(sector_t discard_block_size, | |
1895 | sector_t origin_size) | |
1896 | { | |
1897 | (void) sector_div(origin_size, discard_block_size); | |
1898 | ||
1899 | return origin_size > MAX_DISCARD_BLOCKS; | |
1900 | } | |
1901 | ||
1902 | static sector_t calculate_discard_block_size(sector_t cache_block_size, | |
1903 | sector_t origin_size) | |
1904 | { | |
1905 | sector_t discard_block_size; | |
1906 | ||
1907 | discard_block_size = roundup_pow_of_two(cache_block_size); | |
1908 | ||
1909 | if (origin_size) | |
1910 | while (too_many_discard_blocks(discard_block_size, origin_size)) | |
1911 | discard_block_size *= 2; | |
1912 | ||
1913 | return discard_block_size; | |
1914 | } | |
1915 | ||
f8350daf | 1916 | #define DEFAULT_MIGRATION_THRESHOLD 2048 |
c6b4fcba | 1917 | |
c6b4fcba JT |
1918 | static int cache_create(struct cache_args *ca, struct cache **result) |
1919 | { | |
1920 | int r = 0; | |
1921 | char **error = &ca->ti->error; | |
1922 | struct cache *cache; | |
1923 | struct dm_target *ti = ca->ti; | |
1924 | dm_block_t origin_blocks; | |
1925 | struct dm_cache_metadata *cmd; | |
1926 | bool may_format = ca->features.mode == CM_WRITE; | |
1927 | ||
1928 | cache = kzalloc(sizeof(*cache), GFP_KERNEL); | |
1929 | if (!cache) | |
1930 | return -ENOMEM; | |
1931 | ||
1932 | cache->ti = ca->ti; | |
1933 | ti->private = cache; | |
c6b4fcba JT |
1934 | ti->num_flush_bios = 2; |
1935 | ti->flush_supported = true; | |
1936 | ||
1937 | ti->num_discard_bios = 1; | |
1938 | ti->discards_supported = true; | |
1939 | ti->discard_zeroes_data_unsupported = true; | |
1940 | ||
8c5008fa | 1941 | cache->features = ca->features; |
19b0092e | 1942 | ti->per_bio_data_size = get_per_bio_data_size(cache); |
c6b4fcba | 1943 | |
c6b4fcba JT |
1944 | cache->callbacks.congested_fn = cache_is_congested; |
1945 | dm_table_add_target_callbacks(ti->table, &cache->callbacks); | |
1946 | ||
1947 | cache->metadata_dev = ca->metadata_dev; | |
1948 | cache->origin_dev = ca->origin_dev; | |
1949 | cache->cache_dev = ca->cache_dev; | |
1950 | ||
1951 | ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; | |
1952 | ||
1953 | /* FIXME: factor out this whole section */ | |
1954 | origin_blocks = cache->origin_sectors = ca->origin_sectors; | |
414dd67d | 1955 | origin_blocks = block_div(origin_blocks, ca->block_size); |
c6b4fcba JT |
1956 | cache->origin_blocks = to_oblock(origin_blocks); |
1957 | ||
1958 | cache->sectors_per_block = ca->block_size; | |
1959 | if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) { | |
1960 | r = -EINVAL; | |
1961 | goto bad; | |
1962 | } | |
1963 | ||
1964 | if (ca->block_size & (ca->block_size - 1)) { | |
1965 | dm_block_t cache_size = ca->cache_sectors; | |
1966 | ||
1967 | cache->sectors_per_block_shift = -1; | |
414dd67d | 1968 | cache_size = block_div(cache_size, ca->block_size); |
c6b4fcba JT |
1969 | cache->cache_size = to_cblock(cache_size); |
1970 | } else { | |
1971 | cache->sectors_per_block_shift = __ffs(ca->block_size); | |
1972 | cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift); | |
1973 | } | |
1974 | ||
1975 | r = create_cache_policy(cache, ca, error); | |
1976 | if (r) | |
1977 | goto bad; | |
2f14f4b5 | 1978 | |
c6b4fcba | 1979 | cache->policy_nr_args = ca->policy_argc; |
2f14f4b5 JT |
1980 | cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD; |
1981 | ||
1982 | r = set_config_values(cache, ca->policy_argc, ca->policy_argv); | |
1983 | if (r) { | |
1984 | *error = "Error setting cache policy's config values"; | |
1985 | goto bad; | |
1986 | } | |
c6b4fcba JT |
1987 | |
1988 | cmd = dm_cache_metadata_open(cache->metadata_dev->bdev, | |
1989 | ca->block_size, may_format, | |
1990 | dm_cache_policy_get_hint_size(cache->policy)); | |
1991 | if (IS_ERR(cmd)) { | |
1992 | *error = "Error creating metadata object"; | |
1993 | r = PTR_ERR(cmd); | |
1994 | goto bad; | |
1995 | } | |
1996 | cache->cmd = cmd; | |
1997 | ||
1998 | spin_lock_init(&cache->lock); | |
1999 | bio_list_init(&cache->deferred_bios); | |
2000 | bio_list_init(&cache->deferred_flush_bios); | |
e2e74d61 | 2001 | bio_list_init(&cache->deferred_writethrough_bios); |
c6b4fcba JT |
2002 | INIT_LIST_HEAD(&cache->quiesced_migrations); |
2003 | INIT_LIST_HEAD(&cache->completed_migrations); | |
2004 | INIT_LIST_HEAD(&cache->need_commit_migrations); | |
c6b4fcba JT |
2005 | atomic_set(&cache->nr_migrations, 0); |
2006 | init_waitqueue_head(&cache->migration_wait); | |
2007 | ||
fa4d683a | 2008 | r = -ENOMEM; |
c6b4fcba JT |
2009 | cache->nr_dirty = 0; |
2010 | cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size)); | |
2011 | if (!cache->dirty_bitset) { | |
2012 | *error = "could not allocate dirty bitset"; | |
2013 | goto bad; | |
2014 | } | |
2015 | clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size)); | |
2016 | ||
2017 | cache->discard_block_size = | |
2018 | calculate_discard_block_size(cache->sectors_per_block, | |
2019 | cache->origin_sectors); | |
2020 | cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks); | |
2021 | cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks)); | |
2022 | if (!cache->discard_bitset) { | |
2023 | *error = "could not allocate discard bitset"; | |
2024 | goto bad; | |
2025 | } | |
2026 | clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); | |
2027 | ||
2028 | cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); | |
2029 | if (IS_ERR(cache->copier)) { | |
2030 | *error = "could not create kcopyd client"; | |
2031 | r = PTR_ERR(cache->copier); | |
2032 | goto bad; | |
2033 | } | |
2034 | ||
2035 | cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); | |
2036 | if (!cache->wq) { | |
2037 | *error = "could not create workqueue for metadata object"; | |
2038 | goto bad; | |
2039 | } | |
2040 | INIT_WORK(&cache->worker, do_worker); | |
2041 | INIT_DELAYED_WORK(&cache->waker, do_waker); | |
2042 | cache->last_commit_jiffies = jiffies; | |
2043 | ||
2044 | cache->prison = dm_bio_prison_create(PRISON_CELLS); | |
2045 | if (!cache->prison) { | |
2046 | *error = "could not create bio prison"; | |
2047 | goto bad; | |
2048 | } | |
2049 | ||
2050 | cache->all_io_ds = dm_deferred_set_create(); | |
2051 | if (!cache->all_io_ds) { | |
2052 | *error = "could not create all_io deferred set"; | |
2053 | goto bad; | |
2054 | } | |
2055 | ||
2056 | cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE, | |
2057 | migration_cache); | |
2058 | if (!cache->migration_pool) { | |
2059 | *error = "Error creating cache's migration mempool"; | |
2060 | goto bad; | |
2061 | } | |
2062 | ||
2063 | cache->next_migration = NULL; | |
2064 | ||
2065 | cache->need_tick_bio = true; | |
2066 | cache->sized = false; | |
2067 | cache->quiescing = false; | |
2068 | cache->commit_requested = false; | |
2069 | cache->loaded_mappings = false; | |
2070 | cache->loaded_discards = false; | |
2071 | ||
2072 | load_stats(cache); | |
2073 | ||
2074 | atomic_set(&cache->stats.demotion, 0); | |
2075 | atomic_set(&cache->stats.promotion, 0); | |
2076 | atomic_set(&cache->stats.copies_avoided, 0); | |
2077 | atomic_set(&cache->stats.cache_cell_clash, 0); | |
2078 | atomic_set(&cache->stats.commit_count, 0); | |
2079 | atomic_set(&cache->stats.discard_count, 0); | |
2080 | ||
2081 | *result = cache; | |
2082 | return 0; | |
2083 | ||
2084 | bad: | |
2085 | destroy(cache); | |
2086 | return r; | |
2087 | } | |
2088 | ||
2089 | static int copy_ctr_args(struct cache *cache, int argc, const char **argv) | |
2090 | { | |
2091 | unsigned i; | |
2092 | const char **copy; | |
2093 | ||
2094 | copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL); | |
2095 | if (!copy) | |
2096 | return -ENOMEM; | |
2097 | for (i = 0; i < argc; i++) { | |
2098 | copy[i] = kstrdup(argv[i], GFP_KERNEL); | |
2099 | if (!copy[i]) { | |
2100 | while (i--) | |
2101 | kfree(copy[i]); | |
2102 | kfree(copy); | |
2103 | return -ENOMEM; | |
2104 | } | |
2105 | } | |
2106 | ||
2107 | cache->nr_ctr_args = argc; | |
2108 | cache->ctr_args = copy; | |
2109 | ||
2110 | return 0; | |
2111 | } | |
2112 | ||
2113 | static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
2114 | { | |
2115 | int r = -EINVAL; | |
2116 | struct cache_args *ca; | |
2117 | struct cache *cache = NULL; | |
2118 | ||
2119 | ca = kzalloc(sizeof(*ca), GFP_KERNEL); | |
2120 | if (!ca) { | |
2121 | ti->error = "Error allocating memory for cache"; | |
2122 | return -ENOMEM; | |
2123 | } | |
2124 | ca->ti = ti; | |
2125 | ||
2126 | r = parse_cache_args(ca, argc, argv, &ti->error); | |
2127 | if (r) | |
2128 | goto out; | |
2129 | ||
2130 | r = cache_create(ca, &cache); | |
617a0b89 HM |
2131 | if (r) |
2132 | goto out; | |
c6b4fcba JT |
2133 | |
2134 | r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3); | |
2135 | if (r) { | |
2136 | destroy(cache); | |
2137 | goto out; | |
2138 | } | |
2139 | ||
2140 | ti->private = cache; | |
2141 | ||
2142 | out: | |
2143 | destroy_cache_args(ca); | |
2144 | return r; | |
2145 | } | |
2146 | ||
c6b4fcba JT |
2147 | static int cache_map(struct dm_target *ti, struct bio *bio) |
2148 | { | |
2149 | struct cache *cache = ti->private; | |
2150 | ||
2151 | int r; | |
2152 | dm_oblock_t block = get_bio_block(cache, bio); | |
19b0092e | 2153 | size_t pb_data_size = get_per_bio_data_size(cache); |
c6b4fcba JT |
2154 | bool can_migrate = false; |
2155 | bool discarded_block; | |
2156 | struct dm_bio_prison_cell *cell; | |
2157 | struct policy_result lookup_result; | |
2158 | struct per_bio_data *pb; | |
2159 | ||
2160 | if (from_oblock(block) > from_oblock(cache->origin_blocks)) { | |
2161 | /* | |
2162 | * This can only occur if the io goes to a partial block at | |
2163 | * the end of the origin device. We don't cache these. | |
2164 | * Just remap to the origin and carry on. | |
2165 | */ | |
2166 | remap_to_origin_clear_discard(cache, bio, block); | |
2167 | return DM_MAPIO_REMAPPED; | |
2168 | } | |
2169 | ||
19b0092e | 2170 | pb = init_per_bio_data(bio, pb_data_size); |
c6b4fcba JT |
2171 | |
2172 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) { | |
2173 | defer_bio(cache, bio); | |
2174 | return DM_MAPIO_SUBMITTED; | |
2175 | } | |
2176 | ||
2177 | /* | |
2178 | * Check to see if that block is currently migrating. | |
2179 | */ | |
2180 | cell = alloc_prison_cell(cache); | |
2181 | if (!cell) { | |
2182 | defer_bio(cache, bio); | |
2183 | return DM_MAPIO_SUBMITTED; | |
2184 | } | |
2185 | ||
2186 | r = bio_detain(cache, block, bio, cell, | |
2187 | (cell_free_fn) free_prison_cell, | |
2188 | cache, &cell); | |
2189 | if (r) { | |
2190 | if (r < 0) | |
2191 | defer_bio(cache, bio); | |
2192 | ||
2193 | return DM_MAPIO_SUBMITTED; | |
2194 | } | |
2195 | ||
2196 | discarded_block = is_discarded_oblock(cache, block); | |
2197 | ||
2198 | r = policy_map(cache->policy, block, false, can_migrate, discarded_block, | |
2199 | bio, &lookup_result); | |
2200 | if (r == -EWOULDBLOCK) { | |
2201 | cell_defer(cache, cell, true); | |
2202 | return DM_MAPIO_SUBMITTED; | |
2203 | ||
2204 | } else if (r) { | |
2205 | DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r); | |
2206 | bio_io_error(bio); | |
2207 | return DM_MAPIO_SUBMITTED; | |
2208 | } | |
2209 | ||
2210 | switch (lookup_result.op) { | |
2211 | case POLICY_HIT: | |
2212 | inc_hit_counter(cache, bio); | |
2213 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
2214 | ||
e2e74d61 JT |
2215 | if (is_writethrough_io(cache, bio, lookup_result.cblock)) |
2216 | remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); | |
2217 | else | |
c6b4fcba | 2218 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); |
e2e74d61 JT |
2219 | |
2220 | cell_defer(cache, cell, false); | |
c6b4fcba JT |
2221 | break; |
2222 | ||
2223 | case POLICY_MISS: | |
2224 | inc_miss_counter(cache, bio); | |
2225 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
2226 | ||
2227 | if (pb->req_nr != 0) { | |
2228 | /* | |
2229 | * This is a duplicate writethrough io that is no | |
2230 | * longer needed because the block has been demoted. | |
2231 | */ | |
2232 | bio_endio(bio, 0); | |
2233 | cell_defer(cache, cell, false); | |
2234 | return DM_MAPIO_SUBMITTED; | |
2235 | } else { | |
2236 | remap_to_origin_clear_discard(cache, bio, block); | |
2237 | cell_defer(cache, cell, false); | |
2238 | } | |
2239 | break; | |
2240 | ||
2241 | default: | |
2242 | DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__, | |
2243 | (unsigned) lookup_result.op); | |
2244 | bio_io_error(bio); | |
2245 | return DM_MAPIO_SUBMITTED; | |
2246 | } | |
2247 | ||
2248 | return DM_MAPIO_REMAPPED; | |
2249 | } | |
2250 | ||
2251 | static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) | |
2252 | { | |
2253 | struct cache *cache = ti->private; | |
2254 | unsigned long flags; | |
19b0092e MS |
2255 | size_t pb_data_size = get_per_bio_data_size(cache); |
2256 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
2257 | |
2258 | if (pb->tick) { | |
2259 | policy_tick(cache->policy); | |
2260 | ||
2261 | spin_lock_irqsave(&cache->lock, flags); | |
2262 | cache->need_tick_bio = true; | |
2263 | spin_unlock_irqrestore(&cache->lock, flags); | |
2264 | } | |
2265 | ||
2266 | check_for_quiesced_migrations(cache, pb); | |
2267 | ||
2268 | return 0; | |
2269 | } | |
2270 | ||
2271 | static int write_dirty_bitset(struct cache *cache) | |
2272 | { | |
2273 | unsigned i, r; | |
2274 | ||
2275 | for (i = 0; i < from_cblock(cache->cache_size); i++) { | |
2276 | r = dm_cache_set_dirty(cache->cmd, to_cblock(i), | |
2277 | is_dirty(cache, to_cblock(i))); | |
2278 | if (r) | |
2279 | return r; | |
2280 | } | |
2281 | ||
2282 | return 0; | |
2283 | } | |
2284 | ||
2285 | static int write_discard_bitset(struct cache *cache) | |
2286 | { | |
2287 | unsigned i, r; | |
2288 | ||
2289 | r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size, | |
2290 | cache->discard_nr_blocks); | |
2291 | if (r) { | |
2292 | DMERR("could not resize on-disk discard bitset"); | |
2293 | return r; | |
2294 | } | |
2295 | ||
2296 | for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) { | |
2297 | r = dm_cache_set_discard(cache->cmd, to_dblock(i), | |
2298 | is_discarded(cache, to_dblock(i))); | |
2299 | if (r) | |
2300 | return r; | |
2301 | } | |
2302 | ||
2303 | return 0; | |
2304 | } | |
2305 | ||
2306 | static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, | |
2307 | uint32_t hint) | |
2308 | { | |
2309 | struct cache *cache = context; | |
2310 | return dm_cache_save_hint(cache->cmd, cblock, hint); | |
2311 | } | |
2312 | ||
2313 | static int write_hints(struct cache *cache) | |
2314 | { | |
2315 | int r; | |
2316 | ||
2317 | r = dm_cache_begin_hints(cache->cmd, cache->policy); | |
2318 | if (r) { | |
2319 | DMERR("dm_cache_begin_hints failed"); | |
2320 | return r; | |
2321 | } | |
2322 | ||
2323 | r = policy_walk_mappings(cache->policy, save_hint, cache); | |
2324 | if (r) | |
2325 | DMERR("policy_walk_mappings failed"); | |
2326 | ||
2327 | return r; | |
2328 | } | |
2329 | ||
2330 | /* | |
2331 | * returns true on success | |
2332 | */ | |
2333 | static bool sync_metadata(struct cache *cache) | |
2334 | { | |
2335 | int r1, r2, r3, r4; | |
2336 | ||
2337 | r1 = write_dirty_bitset(cache); | |
2338 | if (r1) | |
2339 | DMERR("could not write dirty bitset"); | |
2340 | ||
2341 | r2 = write_discard_bitset(cache); | |
2342 | if (r2) | |
2343 | DMERR("could not write discard bitset"); | |
2344 | ||
2345 | save_stats(cache); | |
2346 | ||
2347 | r3 = write_hints(cache); | |
2348 | if (r3) | |
2349 | DMERR("could not write hints"); | |
2350 | ||
2351 | /* | |
2352 | * If writing the above metadata failed, we still commit, but don't | |
2353 | * set the clean shutdown flag. This will effectively force every | |
2354 | * dirty bit to be set on reload. | |
2355 | */ | |
2356 | r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3); | |
2357 | if (r4) | |
2358 | DMERR("could not write cache metadata. Data loss may occur."); | |
2359 | ||
2360 | return !r1 && !r2 && !r3 && !r4; | |
2361 | } | |
2362 | ||
2363 | static void cache_postsuspend(struct dm_target *ti) | |
2364 | { | |
2365 | struct cache *cache = ti->private; | |
2366 | ||
2367 | start_quiescing(cache); | |
2368 | wait_for_migrations(cache); | |
2369 | stop_worker(cache); | |
2370 | requeue_deferred_io(cache); | |
2371 | stop_quiescing(cache); | |
2372 | ||
2373 | (void) sync_metadata(cache); | |
2374 | } | |
2375 | ||
2376 | static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, | |
2377 | bool dirty, uint32_t hint, bool hint_valid) | |
2378 | { | |
2379 | int r; | |
2380 | struct cache *cache = context; | |
2381 | ||
2382 | r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid); | |
2383 | if (r) | |
2384 | return r; | |
2385 | ||
2386 | if (dirty) | |
2387 | set_dirty(cache, oblock, cblock); | |
2388 | else | |
2389 | clear_dirty(cache, oblock, cblock); | |
2390 | ||
2391 | return 0; | |
2392 | } | |
2393 | ||
2394 | static int load_discard(void *context, sector_t discard_block_size, | |
2395 | dm_dblock_t dblock, bool discard) | |
2396 | { | |
2397 | struct cache *cache = context; | |
2398 | ||
2399 | /* FIXME: handle mis-matched block size */ | |
2400 | ||
2401 | if (discard) | |
2402 | set_discard(cache, dblock); | |
2403 | else | |
2404 | clear_discard(cache, dblock); | |
2405 | ||
2406 | return 0; | |
2407 | } | |
2408 | ||
2409 | static int cache_preresume(struct dm_target *ti) | |
2410 | { | |
2411 | int r = 0; | |
2412 | struct cache *cache = ti->private; | |
2413 | sector_t actual_cache_size = get_dev_size(cache->cache_dev); | |
2414 | (void) sector_div(actual_cache_size, cache->sectors_per_block); | |
2415 | ||
2416 | /* | |
2417 | * Check to see if the cache has resized. | |
2418 | */ | |
2419 | if (from_cblock(cache->cache_size) != actual_cache_size || !cache->sized) { | |
2420 | cache->cache_size = to_cblock(actual_cache_size); | |
2421 | ||
2422 | r = dm_cache_resize(cache->cmd, cache->cache_size); | |
2423 | if (r) { | |
2424 | DMERR("could not resize cache metadata"); | |
2425 | return r; | |
2426 | } | |
2427 | ||
2428 | cache->sized = true; | |
2429 | } | |
2430 | ||
2431 | if (!cache->loaded_mappings) { | |
ea2dd8c1 | 2432 | r = dm_cache_load_mappings(cache->cmd, cache->policy, |
c6b4fcba JT |
2433 | load_mapping, cache); |
2434 | if (r) { | |
2435 | DMERR("could not load cache mappings"); | |
2436 | return r; | |
2437 | } | |
2438 | ||
2439 | cache->loaded_mappings = true; | |
2440 | } | |
2441 | ||
2442 | if (!cache->loaded_discards) { | |
2443 | r = dm_cache_load_discards(cache->cmd, load_discard, cache); | |
2444 | if (r) { | |
2445 | DMERR("could not load origin discards"); | |
2446 | return r; | |
2447 | } | |
2448 | ||
2449 | cache->loaded_discards = true; | |
2450 | } | |
2451 | ||
2452 | return r; | |
2453 | } | |
2454 | ||
2455 | static void cache_resume(struct dm_target *ti) | |
2456 | { | |
2457 | struct cache *cache = ti->private; | |
2458 | ||
2459 | cache->need_tick_bio = true; | |
2460 | do_waker(&cache->waker.work); | |
2461 | } | |
2462 | ||
2463 | /* | |
2464 | * Status format: | |
2465 | * | |
2466 | * <#used metadata blocks>/<#total metadata blocks> | |
2467 | * <#read hits> <#read misses> <#write hits> <#write misses> | |
2468 | * <#demotions> <#promotions> <#blocks in cache> <#dirty> | |
2469 | * <#features> <features>* | |
2470 | * <#core args> <core args> | |
2471 | * <#policy args> <policy args>* | |
2472 | */ | |
2473 | static void cache_status(struct dm_target *ti, status_type_t type, | |
2474 | unsigned status_flags, char *result, unsigned maxlen) | |
2475 | { | |
2476 | int r = 0; | |
2477 | unsigned i; | |
2478 | ssize_t sz = 0; | |
2479 | dm_block_t nr_free_blocks_metadata = 0; | |
2480 | dm_block_t nr_blocks_metadata = 0; | |
2481 | char buf[BDEVNAME_SIZE]; | |
2482 | struct cache *cache = ti->private; | |
2483 | dm_cblock_t residency; | |
2484 | ||
2485 | switch (type) { | |
2486 | case STATUSTYPE_INFO: | |
2487 | /* Commit to ensure statistics aren't out-of-date */ | |
2488 | if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) { | |
2489 | r = dm_cache_commit(cache->cmd, false); | |
2490 | if (r) | |
2491 | DMERR("could not commit metadata for accurate status"); | |
2492 | } | |
2493 | ||
2494 | r = dm_cache_get_free_metadata_block_count(cache->cmd, | |
2495 | &nr_free_blocks_metadata); | |
2496 | if (r) { | |
2497 | DMERR("could not get metadata free block count"); | |
2498 | goto err; | |
2499 | } | |
2500 | ||
2501 | r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata); | |
2502 | if (r) { | |
2503 | DMERR("could not get metadata device size"); | |
2504 | goto err; | |
2505 | } | |
2506 | ||
2507 | residency = policy_residency(cache->policy); | |
2508 | ||
2509 | DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ", | |
2510 | (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), | |
2511 | (unsigned long long)nr_blocks_metadata, | |
2512 | (unsigned) atomic_read(&cache->stats.read_hit), | |
2513 | (unsigned) atomic_read(&cache->stats.read_miss), | |
2514 | (unsigned) atomic_read(&cache->stats.write_hit), | |
2515 | (unsigned) atomic_read(&cache->stats.write_miss), | |
2516 | (unsigned) atomic_read(&cache->stats.demotion), | |
2517 | (unsigned) atomic_read(&cache->stats.promotion), | |
2518 | (unsigned long long) from_cblock(residency), | |
2519 | cache->nr_dirty); | |
2520 | ||
2521 | if (cache->features.write_through) | |
2522 | DMEMIT("1 writethrough "); | |
2523 | else | |
2524 | DMEMIT("0 "); | |
2525 | ||
2526 | DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold); | |
2527 | if (sz < maxlen) { | |
2528 | r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz); | |
2529 | if (r) | |
2530 | DMERR("policy_emit_config_values returned %d", r); | |
2531 | } | |
2532 | ||
2533 | break; | |
2534 | ||
2535 | case STATUSTYPE_TABLE: | |
2536 | format_dev_t(buf, cache->metadata_dev->bdev->bd_dev); | |
2537 | DMEMIT("%s ", buf); | |
2538 | format_dev_t(buf, cache->cache_dev->bdev->bd_dev); | |
2539 | DMEMIT("%s ", buf); | |
2540 | format_dev_t(buf, cache->origin_dev->bdev->bd_dev); | |
2541 | DMEMIT("%s", buf); | |
2542 | ||
2543 | for (i = 0; i < cache->nr_ctr_args - 1; i++) | |
2544 | DMEMIT(" %s", cache->ctr_args[i]); | |
2545 | if (cache->nr_ctr_args) | |
2546 | DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]); | |
2547 | } | |
2548 | ||
2549 | return; | |
2550 | ||
2551 | err: | |
2552 | DMEMIT("Error"); | |
2553 | } | |
2554 | ||
c6b4fcba JT |
2555 | /* |
2556 | * Supports <key> <value>. | |
2557 | * | |
2558 | * The key migration_threshold is supported by the cache target core. | |
2559 | */ | |
2560 | static int cache_message(struct dm_target *ti, unsigned argc, char **argv) | |
2561 | { | |
c6b4fcba JT |
2562 | struct cache *cache = ti->private; |
2563 | ||
2564 | if (argc != 2) | |
2565 | return -EINVAL; | |
2566 | ||
2f14f4b5 | 2567 | return set_config_value(cache, argv[0], argv[1]); |
c6b4fcba JT |
2568 | } |
2569 | ||
2570 | static int cache_iterate_devices(struct dm_target *ti, | |
2571 | iterate_devices_callout_fn fn, void *data) | |
2572 | { | |
2573 | int r = 0; | |
2574 | struct cache *cache = ti->private; | |
2575 | ||
2576 | r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data); | |
2577 | if (!r) | |
2578 | r = fn(ti, cache->origin_dev, 0, ti->len, data); | |
2579 | ||
2580 | return r; | |
2581 | } | |
2582 | ||
2583 | /* | |
2584 | * We assume I/O is going to the origin (which is the volume | |
2585 | * more likely to have restrictions e.g. by being striped). | |
2586 | * (Looking up the exact location of the data would be expensive | |
2587 | * and could always be out of date by the time the bio is submitted.) | |
2588 | */ | |
2589 | static int cache_bvec_merge(struct dm_target *ti, | |
2590 | struct bvec_merge_data *bvm, | |
2591 | struct bio_vec *biovec, int max_size) | |
2592 | { | |
2593 | struct cache *cache = ti->private; | |
2594 | struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev); | |
2595 | ||
2596 | if (!q->merge_bvec_fn) | |
2597 | return max_size; | |
2598 | ||
2599 | bvm->bi_bdev = cache->origin_dev->bdev; | |
2600 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
2601 | } | |
2602 | ||
2603 | static void set_discard_limits(struct cache *cache, struct queue_limits *limits) | |
2604 | { | |
2605 | /* | |
2606 | * FIXME: these limits may be incompatible with the cache device | |
2607 | */ | |
2608 | limits->max_discard_sectors = cache->discard_block_size * 1024; | |
2609 | limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT; | |
2610 | } | |
2611 | ||
2612 | static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
2613 | { | |
2614 | struct cache *cache = ti->private; | |
f6109372 | 2615 | uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; |
c6b4fcba | 2616 | |
f6109372 MS |
2617 | /* |
2618 | * If the system-determined stacked limits are compatible with the | |
2619 | * cache's blocksize (io_opt is a factor) do not override them. | |
2620 | */ | |
2621 | if (io_opt_sectors < cache->sectors_per_block || | |
2622 | do_div(io_opt_sectors, cache->sectors_per_block)) { | |
2623 | blk_limits_io_min(limits, 0); | |
2624 | blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT); | |
2625 | } | |
c6b4fcba JT |
2626 | set_discard_limits(cache, limits); |
2627 | } | |
2628 | ||
2629 | /*----------------------------------------------------------------*/ | |
2630 | ||
2631 | static struct target_type cache_target = { | |
2632 | .name = "cache", | |
2f14f4b5 | 2633 | .version = {1, 1, 1}, |
c6b4fcba JT |
2634 | .module = THIS_MODULE, |
2635 | .ctr = cache_ctr, | |
2636 | .dtr = cache_dtr, | |
2637 | .map = cache_map, | |
2638 | .end_io = cache_end_io, | |
2639 | .postsuspend = cache_postsuspend, | |
2640 | .preresume = cache_preresume, | |
2641 | .resume = cache_resume, | |
2642 | .status = cache_status, | |
2643 | .message = cache_message, | |
2644 | .iterate_devices = cache_iterate_devices, | |
2645 | .merge = cache_bvec_merge, | |
2646 | .io_hints = cache_io_hints, | |
2647 | }; | |
2648 | ||
2649 | static int __init dm_cache_init(void) | |
2650 | { | |
2651 | int r; | |
2652 | ||
2653 | r = dm_register_target(&cache_target); | |
2654 | if (r) { | |
2655 | DMERR("cache target registration failed: %d", r); | |
2656 | return r; | |
2657 | } | |
2658 | ||
2659 | migration_cache = KMEM_CACHE(dm_cache_migration, 0); | |
2660 | if (!migration_cache) { | |
2661 | dm_unregister_target(&cache_target); | |
2662 | return -ENOMEM; | |
2663 | } | |
2664 | ||
2665 | return 0; | |
2666 | } | |
2667 | ||
2668 | static void __exit dm_cache_exit(void) | |
2669 | { | |
2670 | dm_unregister_target(&cache_target); | |
2671 | kmem_cache_destroy(migration_cache); | |
2672 | } | |
2673 | ||
2674 | module_init(dm_cache_init); | |
2675 | module_exit(dm_cache_exit); | |
2676 | ||
2677 | MODULE_DESCRIPTION(DM_NAME " cache target"); | |
2678 | MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); | |
2679 | MODULE_LICENSE("GPL"); |