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 | ||
c9d28d5d JT |
64 | /* |
65 | * There are a couple of places where we let a bio run, but want to do some | |
66 | * work before calling its endio function. We do this by temporarily | |
67 | * changing the endio fn. | |
68 | */ | |
69 | struct dm_hook_info { | |
70 | bio_end_io_t *bi_end_io; | |
71 | void *bi_private; | |
72 | }; | |
73 | ||
74 | static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio, | |
75 | bio_end_io_t *bi_end_io, void *bi_private) | |
76 | { | |
77 | h->bi_end_io = bio->bi_end_io; | |
78 | h->bi_private = bio->bi_private; | |
79 | ||
80 | bio->bi_end_io = bi_end_io; | |
81 | bio->bi_private = bi_private; | |
82 | } | |
83 | ||
84 | static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio) | |
85 | { | |
86 | bio->bi_end_io = h->bi_end_io; | |
87 | bio->bi_private = h->bi_private; | |
88 | } | |
89 | ||
90 | /*----------------------------------------------------------------*/ | |
91 | ||
c6b4fcba JT |
92 | #define PRISON_CELLS 1024 |
93 | #define MIGRATION_POOL_SIZE 128 | |
94 | #define COMMIT_PERIOD HZ | |
95 | #define MIGRATION_COUNT_WINDOW 10 | |
96 | ||
97 | /* | |
05473044 MS |
98 | * The block size of the device holding cache data must be |
99 | * between 32KB and 1GB. | |
c6b4fcba JT |
100 | */ |
101 | #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) | |
05473044 | 102 | #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) |
c6b4fcba JT |
103 | |
104 | /* | |
105 | * FIXME: the cache is read/write for the time being. | |
106 | */ | |
107 | enum cache_mode { | |
108 | CM_WRITE, /* metadata may be changed */ | |
109 | CM_READ_ONLY, /* metadata may not be changed */ | |
110 | }; | |
111 | ||
112 | struct cache_features { | |
113 | enum cache_mode mode; | |
114 | bool write_through:1; | |
115 | }; | |
116 | ||
117 | struct cache_stats { | |
118 | atomic_t read_hit; | |
119 | atomic_t read_miss; | |
120 | atomic_t write_hit; | |
121 | atomic_t write_miss; | |
122 | atomic_t demotion; | |
123 | atomic_t promotion; | |
124 | atomic_t copies_avoided; | |
125 | atomic_t cache_cell_clash; | |
126 | atomic_t commit_count; | |
127 | atomic_t discard_count; | |
128 | }; | |
129 | ||
130 | struct cache { | |
131 | struct dm_target *ti; | |
132 | struct dm_target_callbacks callbacks; | |
133 | ||
c9ec5d7c MS |
134 | struct dm_cache_metadata *cmd; |
135 | ||
c6b4fcba JT |
136 | /* |
137 | * Metadata is written to this device. | |
138 | */ | |
139 | struct dm_dev *metadata_dev; | |
140 | ||
141 | /* | |
142 | * The slower of the two data devices. Typically a spindle. | |
143 | */ | |
144 | struct dm_dev *origin_dev; | |
145 | ||
146 | /* | |
147 | * The faster of the two data devices. Typically an SSD. | |
148 | */ | |
149 | struct dm_dev *cache_dev; | |
150 | ||
c6b4fcba JT |
151 | /* |
152 | * Size of the origin device in _complete_ blocks and native sectors. | |
153 | */ | |
154 | dm_oblock_t origin_blocks; | |
155 | sector_t origin_sectors; | |
156 | ||
157 | /* | |
158 | * Size of the cache device in blocks. | |
159 | */ | |
160 | dm_cblock_t cache_size; | |
161 | ||
162 | /* | |
163 | * Fields for converting from sectors to blocks. | |
164 | */ | |
165 | uint32_t sectors_per_block; | |
166 | int sectors_per_block_shift; | |
167 | ||
c6b4fcba JT |
168 | spinlock_t lock; |
169 | struct bio_list deferred_bios; | |
170 | struct bio_list deferred_flush_bios; | |
e2e74d61 | 171 | struct bio_list deferred_writethrough_bios; |
c6b4fcba JT |
172 | struct list_head quiesced_migrations; |
173 | struct list_head completed_migrations; | |
174 | struct list_head need_commit_migrations; | |
175 | sector_t migration_threshold; | |
c6b4fcba | 176 | wait_queue_head_t migration_wait; |
c9ec5d7c | 177 | atomic_t nr_migrations; |
c6b4fcba | 178 | |
66cb1910 | 179 | wait_queue_head_t quiescing_wait; |
238f8363 | 180 | atomic_t quiescing; |
66cb1910 JT |
181 | atomic_t quiescing_ack; |
182 | ||
c6b4fcba JT |
183 | /* |
184 | * cache_size entries, dirty if set | |
185 | */ | |
186 | dm_cblock_t nr_dirty; | |
187 | unsigned long *dirty_bitset; | |
188 | ||
189 | /* | |
190 | * origin_blocks entries, discarded if set. | |
191 | */ | |
c6b4fcba JT |
192 | dm_dblock_t discard_nr_blocks; |
193 | unsigned long *discard_bitset; | |
c9ec5d7c MS |
194 | uint32_t discard_block_size; /* a power of 2 times sectors per block */ |
195 | ||
196 | /* | |
197 | * Rather than reconstructing the table line for the status we just | |
198 | * save it and regurgitate. | |
199 | */ | |
200 | unsigned nr_ctr_args; | |
201 | const char **ctr_args; | |
c6b4fcba JT |
202 | |
203 | struct dm_kcopyd_client *copier; | |
204 | struct workqueue_struct *wq; | |
205 | struct work_struct worker; | |
206 | ||
207 | struct delayed_work waker; | |
208 | unsigned long last_commit_jiffies; | |
209 | ||
210 | struct dm_bio_prison *prison; | |
211 | struct dm_deferred_set *all_io_ds; | |
212 | ||
213 | mempool_t *migration_pool; | |
214 | struct dm_cache_migration *next_migration; | |
215 | ||
216 | struct dm_cache_policy *policy; | |
217 | unsigned policy_nr_args; | |
218 | ||
219 | bool need_tick_bio:1; | |
220 | bool sized:1; | |
c6b4fcba JT |
221 | bool commit_requested:1; |
222 | bool loaded_mappings:1; | |
223 | bool loaded_discards:1; | |
224 | ||
c6b4fcba | 225 | /* |
c9ec5d7c | 226 | * Cache features such as write-through. |
c6b4fcba | 227 | */ |
c9ec5d7c MS |
228 | struct cache_features features; |
229 | ||
230 | struct cache_stats stats; | |
c6b4fcba JT |
231 | }; |
232 | ||
233 | struct per_bio_data { | |
234 | bool tick:1; | |
235 | unsigned req_nr:2; | |
236 | struct dm_deferred_entry *all_io_entry; | |
e2e74d61 | 237 | |
19b0092e MS |
238 | /* |
239 | * writethrough fields. These MUST remain at the end of this | |
240 | * structure and the 'cache' member must be the first as it | |
aeed1420 | 241 | * is used to determine the offset of the writethrough fields. |
19b0092e | 242 | */ |
e2e74d61 JT |
243 | struct cache *cache; |
244 | dm_cblock_t cblock; | |
c9d28d5d | 245 | struct dm_hook_info hook_info; |
b844fe69 | 246 | struct dm_bio_details bio_details; |
c6b4fcba JT |
247 | }; |
248 | ||
249 | struct dm_cache_migration { | |
250 | struct list_head list; | |
251 | struct cache *cache; | |
252 | ||
253 | unsigned long start_jiffies; | |
254 | dm_oblock_t old_oblock; | |
255 | dm_oblock_t new_oblock; | |
256 | dm_cblock_t cblock; | |
257 | ||
258 | bool err:1; | |
259 | bool writeback:1; | |
260 | bool demote:1; | |
261 | bool promote:1; | |
c9d28d5d | 262 | bool requeue_holder:1; |
c6b4fcba JT |
263 | |
264 | struct dm_bio_prison_cell *old_ocell; | |
265 | struct dm_bio_prison_cell *new_ocell; | |
266 | }; | |
267 | ||
268 | /* | |
269 | * Processing a bio in the worker thread may require these memory | |
270 | * allocations. We prealloc to avoid deadlocks (the same worker thread | |
271 | * frees them back to the mempool). | |
272 | */ | |
273 | struct prealloc { | |
274 | struct dm_cache_migration *mg; | |
275 | struct dm_bio_prison_cell *cell1; | |
276 | struct dm_bio_prison_cell *cell2; | |
277 | }; | |
278 | ||
279 | static void wake_worker(struct cache *cache) | |
280 | { | |
281 | queue_work(cache->wq, &cache->worker); | |
282 | } | |
283 | ||
284 | /*----------------------------------------------------------------*/ | |
285 | ||
286 | static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache) | |
287 | { | |
288 | /* FIXME: change to use a local slab. */ | |
289 | return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT); | |
290 | } | |
291 | ||
292 | static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell) | |
293 | { | |
294 | dm_bio_prison_free_cell(cache->prison, cell); | |
295 | } | |
296 | ||
297 | static int prealloc_data_structs(struct cache *cache, struct prealloc *p) | |
298 | { | |
299 | if (!p->mg) { | |
300 | p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT); | |
301 | if (!p->mg) | |
302 | return -ENOMEM; | |
303 | } | |
304 | ||
305 | if (!p->cell1) { | |
306 | p->cell1 = alloc_prison_cell(cache); | |
307 | if (!p->cell1) | |
308 | return -ENOMEM; | |
309 | } | |
310 | ||
311 | if (!p->cell2) { | |
312 | p->cell2 = alloc_prison_cell(cache); | |
313 | if (!p->cell2) | |
314 | return -ENOMEM; | |
315 | } | |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
320 | static void prealloc_free_structs(struct cache *cache, struct prealloc *p) | |
321 | { | |
322 | if (p->cell2) | |
323 | free_prison_cell(cache, p->cell2); | |
324 | ||
325 | if (p->cell1) | |
326 | free_prison_cell(cache, p->cell1); | |
327 | ||
328 | if (p->mg) | |
329 | mempool_free(p->mg, cache->migration_pool); | |
330 | } | |
331 | ||
332 | static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p) | |
333 | { | |
334 | struct dm_cache_migration *mg = p->mg; | |
335 | ||
336 | BUG_ON(!mg); | |
337 | p->mg = NULL; | |
338 | ||
339 | return mg; | |
340 | } | |
341 | ||
342 | /* | |
343 | * You must have a cell within the prealloc struct to return. If not this | |
344 | * function will BUG() rather than returning NULL. | |
345 | */ | |
346 | static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p) | |
347 | { | |
348 | struct dm_bio_prison_cell *r = NULL; | |
349 | ||
350 | if (p->cell1) { | |
351 | r = p->cell1; | |
352 | p->cell1 = NULL; | |
353 | ||
354 | } else if (p->cell2) { | |
355 | r = p->cell2; | |
356 | p->cell2 = NULL; | |
357 | } else | |
358 | BUG(); | |
359 | ||
360 | return r; | |
361 | } | |
362 | ||
363 | /* | |
364 | * You can't have more than two cells in a prealloc struct. BUG() will be | |
365 | * called if you try and overfill. | |
366 | */ | |
367 | static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell) | |
368 | { | |
369 | if (!p->cell2) | |
370 | p->cell2 = cell; | |
371 | ||
372 | else if (!p->cell1) | |
373 | p->cell1 = cell; | |
374 | ||
375 | else | |
376 | BUG(); | |
377 | } | |
378 | ||
379 | /*----------------------------------------------------------------*/ | |
380 | ||
381 | static void build_key(dm_oblock_t oblock, struct dm_cell_key *key) | |
382 | { | |
383 | key->virtual = 0; | |
384 | key->dev = 0; | |
385 | key->block = from_oblock(oblock); | |
386 | } | |
387 | ||
388 | /* | |
389 | * The caller hands in a preallocated cell, and a free function for it. | |
390 | * The cell will be freed if there's an error, or if it wasn't used because | |
391 | * a cell with that key already exists. | |
392 | */ | |
393 | typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell); | |
394 | ||
395 | static int bio_detain(struct cache *cache, dm_oblock_t oblock, | |
396 | struct bio *bio, struct dm_bio_prison_cell *cell_prealloc, | |
397 | cell_free_fn free_fn, void *free_context, | |
398 | struct dm_bio_prison_cell **cell_result) | |
399 | { | |
400 | int r; | |
401 | struct dm_cell_key key; | |
402 | ||
403 | build_key(oblock, &key); | |
404 | r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result); | |
405 | if (r) | |
406 | free_fn(free_context, cell_prealloc); | |
407 | ||
408 | return r; | |
409 | } | |
410 | ||
411 | static int get_cell(struct cache *cache, | |
412 | dm_oblock_t oblock, | |
413 | struct prealloc *structs, | |
414 | struct dm_bio_prison_cell **cell_result) | |
415 | { | |
416 | int r; | |
417 | struct dm_cell_key key; | |
418 | struct dm_bio_prison_cell *cell_prealloc; | |
419 | ||
420 | cell_prealloc = prealloc_get_cell(structs); | |
421 | ||
422 | build_key(oblock, &key); | |
423 | r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result); | |
424 | if (r) | |
425 | prealloc_put_cell(structs, cell_prealloc); | |
426 | ||
427 | return r; | |
428 | } | |
429 | ||
aeed1420 | 430 | /*----------------------------------------------------------------*/ |
c6b4fcba JT |
431 | |
432 | static bool is_dirty(struct cache *cache, dm_cblock_t b) | |
433 | { | |
434 | return test_bit(from_cblock(b), cache->dirty_bitset); | |
435 | } | |
436 | ||
437 | static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | |
438 | { | |
439 | if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
440 | cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) + 1); | |
441 | policy_set_dirty(cache->policy, oblock); | |
442 | } | |
443 | } | |
444 | ||
445 | static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | |
446 | { | |
447 | if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
448 | policy_clear_dirty(cache->policy, oblock); | |
449 | cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) - 1); | |
450 | if (!from_cblock(cache->nr_dirty)) | |
451 | dm_table_event(cache->ti->table); | |
452 | } | |
453 | } | |
454 | ||
455 | /*----------------------------------------------------------------*/ | |
aeed1420 | 456 | |
c6b4fcba JT |
457 | static bool block_size_is_power_of_two(struct cache *cache) |
458 | { | |
459 | return cache->sectors_per_block_shift >= 0; | |
460 | } | |
461 | ||
43aeaa29 MP |
462 | /* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */ |
463 | #if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6 | |
464 | __always_inline | |
465 | #endif | |
414dd67d JT |
466 | static dm_block_t block_div(dm_block_t b, uint32_t n) |
467 | { | |
468 | do_div(b, n); | |
469 | ||
470 | return b; | |
471 | } | |
472 | ||
c6b4fcba JT |
473 | static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) |
474 | { | |
414dd67d | 475 | uint32_t discard_blocks = cache->discard_block_size; |
c6b4fcba JT |
476 | dm_block_t b = from_oblock(oblock); |
477 | ||
478 | if (!block_size_is_power_of_two(cache)) | |
414dd67d | 479 | discard_blocks = discard_blocks / cache->sectors_per_block; |
c6b4fcba JT |
480 | else |
481 | discard_blocks >>= cache->sectors_per_block_shift; | |
482 | ||
414dd67d | 483 | b = block_div(b, discard_blocks); |
c6b4fcba JT |
484 | |
485 | return to_dblock(b); | |
486 | } | |
487 | ||
488 | static void set_discard(struct cache *cache, dm_dblock_t b) | |
489 | { | |
490 | unsigned long flags; | |
491 | ||
492 | atomic_inc(&cache->stats.discard_count); | |
493 | ||
494 | spin_lock_irqsave(&cache->lock, flags); | |
495 | set_bit(from_dblock(b), cache->discard_bitset); | |
496 | spin_unlock_irqrestore(&cache->lock, flags); | |
497 | } | |
498 | ||
499 | static void clear_discard(struct cache *cache, dm_dblock_t b) | |
500 | { | |
501 | unsigned long flags; | |
502 | ||
503 | spin_lock_irqsave(&cache->lock, flags); | |
504 | clear_bit(from_dblock(b), cache->discard_bitset); | |
505 | spin_unlock_irqrestore(&cache->lock, flags); | |
506 | } | |
507 | ||
508 | static bool is_discarded(struct cache *cache, dm_dblock_t b) | |
509 | { | |
510 | int r; | |
511 | unsigned long flags; | |
512 | ||
513 | spin_lock_irqsave(&cache->lock, flags); | |
514 | r = test_bit(from_dblock(b), cache->discard_bitset); | |
515 | spin_unlock_irqrestore(&cache->lock, flags); | |
516 | ||
517 | return r; | |
518 | } | |
519 | ||
520 | static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) | |
521 | { | |
522 | int r; | |
523 | unsigned long flags; | |
524 | ||
525 | spin_lock_irqsave(&cache->lock, flags); | |
526 | r = test_bit(from_dblock(oblock_to_dblock(cache, b)), | |
527 | cache->discard_bitset); | |
528 | spin_unlock_irqrestore(&cache->lock, flags); | |
529 | ||
530 | return r; | |
531 | } | |
532 | ||
533 | /*----------------------------------------------------------------*/ | |
534 | ||
535 | static void load_stats(struct cache *cache) | |
536 | { | |
537 | struct dm_cache_statistics stats; | |
538 | ||
539 | dm_cache_metadata_get_stats(cache->cmd, &stats); | |
540 | atomic_set(&cache->stats.read_hit, stats.read_hits); | |
541 | atomic_set(&cache->stats.read_miss, stats.read_misses); | |
542 | atomic_set(&cache->stats.write_hit, stats.write_hits); | |
543 | atomic_set(&cache->stats.write_miss, stats.write_misses); | |
544 | } | |
545 | ||
546 | static void save_stats(struct cache *cache) | |
547 | { | |
548 | struct dm_cache_statistics stats; | |
549 | ||
550 | stats.read_hits = atomic_read(&cache->stats.read_hit); | |
551 | stats.read_misses = atomic_read(&cache->stats.read_miss); | |
552 | stats.write_hits = atomic_read(&cache->stats.write_hit); | |
553 | stats.write_misses = atomic_read(&cache->stats.write_miss); | |
554 | ||
555 | dm_cache_metadata_set_stats(cache->cmd, &stats); | |
556 | } | |
557 | ||
558 | /*---------------------------------------------------------------- | |
559 | * Per bio data | |
560 | *--------------------------------------------------------------*/ | |
19b0092e MS |
561 | |
562 | /* | |
563 | * If using writeback, leave out struct per_bio_data's writethrough fields. | |
564 | */ | |
565 | #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) | |
566 | #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) | |
567 | ||
568 | static size_t get_per_bio_data_size(struct cache *cache) | |
569 | { | |
570 | return cache->features.write_through ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; | |
571 | } | |
572 | ||
573 | static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size) | |
c6b4fcba | 574 | { |
19b0092e | 575 | struct per_bio_data *pb = dm_per_bio_data(bio, data_size); |
c6b4fcba JT |
576 | BUG_ON(!pb); |
577 | return pb; | |
578 | } | |
579 | ||
19b0092e | 580 | static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size) |
c6b4fcba | 581 | { |
19b0092e | 582 | struct per_bio_data *pb = get_per_bio_data(bio, data_size); |
c6b4fcba JT |
583 | |
584 | pb->tick = false; | |
585 | pb->req_nr = dm_bio_get_target_bio_nr(bio); | |
586 | pb->all_io_entry = NULL; | |
587 | ||
588 | return pb; | |
589 | } | |
590 | ||
591 | /*---------------------------------------------------------------- | |
592 | * Remapping | |
593 | *--------------------------------------------------------------*/ | |
594 | static void remap_to_origin(struct cache *cache, struct bio *bio) | |
595 | { | |
596 | bio->bi_bdev = cache->origin_dev->bdev; | |
597 | } | |
598 | ||
599 | static void remap_to_cache(struct cache *cache, struct bio *bio, | |
600 | dm_cblock_t cblock) | |
601 | { | |
602 | sector_t bi_sector = bio->bi_sector; | |
603 | ||
604 | bio->bi_bdev = cache->cache_dev->bdev; | |
605 | if (!block_size_is_power_of_two(cache)) | |
606 | bio->bi_sector = (from_cblock(cblock) * cache->sectors_per_block) + | |
607 | sector_div(bi_sector, cache->sectors_per_block); | |
608 | else | |
609 | bio->bi_sector = (from_cblock(cblock) << cache->sectors_per_block_shift) | | |
610 | (bi_sector & (cache->sectors_per_block - 1)); | |
611 | } | |
612 | ||
613 | static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) | |
614 | { | |
615 | unsigned long flags; | |
19b0092e MS |
616 | size_t pb_data_size = get_per_bio_data_size(cache); |
617 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
618 | |
619 | spin_lock_irqsave(&cache->lock, flags); | |
620 | if (cache->need_tick_bio && | |
621 | !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) { | |
622 | pb->tick = true; | |
623 | cache->need_tick_bio = false; | |
624 | } | |
625 | spin_unlock_irqrestore(&cache->lock, flags); | |
626 | } | |
627 | ||
628 | static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, | |
629 | dm_oblock_t oblock) | |
630 | { | |
631 | check_if_tick_bio_needed(cache, bio); | |
632 | remap_to_origin(cache, bio); | |
633 | if (bio_data_dir(bio) == WRITE) | |
634 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | |
635 | } | |
636 | ||
637 | static void remap_to_cache_dirty(struct cache *cache, struct bio *bio, | |
638 | dm_oblock_t oblock, dm_cblock_t cblock) | |
639 | { | |
f8e5f01a | 640 | check_if_tick_bio_needed(cache, bio); |
c6b4fcba JT |
641 | remap_to_cache(cache, bio, cblock); |
642 | if (bio_data_dir(bio) == WRITE) { | |
643 | set_dirty(cache, oblock, cblock); | |
644 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | |
645 | } | |
646 | } | |
647 | ||
648 | static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) | |
649 | { | |
650 | sector_t block_nr = bio->bi_sector; | |
651 | ||
652 | if (!block_size_is_power_of_two(cache)) | |
653 | (void) sector_div(block_nr, cache->sectors_per_block); | |
654 | else | |
655 | block_nr >>= cache->sectors_per_block_shift; | |
656 | ||
657 | return to_oblock(block_nr); | |
658 | } | |
659 | ||
660 | static int bio_triggers_commit(struct cache *cache, struct bio *bio) | |
661 | { | |
662 | return bio->bi_rw & (REQ_FLUSH | REQ_FUA); | |
663 | } | |
664 | ||
665 | static void issue(struct cache *cache, struct bio *bio) | |
666 | { | |
667 | unsigned long flags; | |
668 | ||
669 | if (!bio_triggers_commit(cache, bio)) { | |
670 | generic_make_request(bio); | |
671 | return; | |
672 | } | |
673 | ||
674 | /* | |
675 | * Batch together any bios that trigger commits and then issue a | |
676 | * single commit for them in do_worker(). | |
677 | */ | |
678 | spin_lock_irqsave(&cache->lock, flags); | |
679 | cache->commit_requested = true; | |
680 | bio_list_add(&cache->deferred_flush_bios, bio); | |
681 | spin_unlock_irqrestore(&cache->lock, flags); | |
682 | } | |
683 | ||
e2e74d61 JT |
684 | static void defer_writethrough_bio(struct cache *cache, struct bio *bio) |
685 | { | |
686 | unsigned long flags; | |
687 | ||
688 | spin_lock_irqsave(&cache->lock, flags); | |
689 | bio_list_add(&cache->deferred_writethrough_bios, bio); | |
690 | spin_unlock_irqrestore(&cache->lock, flags); | |
691 | ||
692 | wake_worker(cache); | |
693 | } | |
694 | ||
695 | static void writethrough_endio(struct bio *bio, int err) | |
696 | { | |
19b0092e | 697 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
c9d28d5d JT |
698 | |
699 | dm_unhook_bio(&pb->hook_info, bio); | |
e2e74d61 JT |
700 | |
701 | if (err) { | |
702 | bio_endio(bio, err); | |
703 | return; | |
704 | } | |
705 | ||
b844fe69 | 706 | dm_bio_restore(&pb->bio_details, bio); |
e2e74d61 JT |
707 | remap_to_cache(pb->cache, bio, pb->cblock); |
708 | ||
709 | /* | |
710 | * We can't issue this bio directly, since we're in interrupt | |
aeed1420 | 711 | * context. So it gets put on a bio list for processing by the |
e2e74d61 JT |
712 | * worker thread. |
713 | */ | |
714 | defer_writethrough_bio(pb->cache, bio); | |
715 | } | |
716 | ||
717 | /* | |
718 | * When running in writethrough mode we need to send writes to clean blocks | |
719 | * to both the cache and origin devices. In future we'd like to clone the | |
720 | * bio and send them in parallel, but for now we're doing them in | |
721 | * series as this is easier. | |
722 | */ | |
723 | static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, | |
724 | dm_oblock_t oblock, dm_cblock_t cblock) | |
725 | { | |
19b0092e | 726 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
e2e74d61 JT |
727 | |
728 | pb->cache = cache; | |
729 | pb->cblock = cblock; | |
c9d28d5d | 730 | dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL); |
b844fe69 | 731 | dm_bio_record(&pb->bio_details, bio); |
e2e74d61 JT |
732 | |
733 | remap_to_origin_clear_discard(pb->cache, bio, oblock); | |
734 | } | |
735 | ||
c6b4fcba JT |
736 | /*---------------------------------------------------------------- |
737 | * Migration processing | |
738 | * | |
739 | * Migration covers moving data from the origin device to the cache, or | |
740 | * vice versa. | |
741 | *--------------------------------------------------------------*/ | |
742 | static void free_migration(struct dm_cache_migration *mg) | |
743 | { | |
744 | mempool_free(mg, mg->cache->migration_pool); | |
745 | } | |
746 | ||
747 | static void inc_nr_migrations(struct cache *cache) | |
748 | { | |
749 | atomic_inc(&cache->nr_migrations); | |
750 | } | |
751 | ||
752 | static void dec_nr_migrations(struct cache *cache) | |
753 | { | |
754 | atomic_dec(&cache->nr_migrations); | |
755 | ||
756 | /* | |
757 | * Wake the worker in case we're suspending the target. | |
758 | */ | |
759 | wake_up(&cache->migration_wait); | |
760 | } | |
761 | ||
762 | static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | |
763 | bool holder) | |
764 | { | |
765 | (holder ? dm_cell_release : dm_cell_release_no_holder) | |
766 | (cache->prison, cell, &cache->deferred_bios); | |
767 | free_prison_cell(cache, cell); | |
768 | } | |
769 | ||
770 | static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | |
771 | bool holder) | |
772 | { | |
773 | unsigned long flags; | |
774 | ||
775 | spin_lock_irqsave(&cache->lock, flags); | |
776 | __cell_defer(cache, cell, holder); | |
777 | spin_unlock_irqrestore(&cache->lock, flags); | |
778 | ||
779 | wake_worker(cache); | |
780 | } | |
781 | ||
782 | static void cleanup_migration(struct dm_cache_migration *mg) | |
783 | { | |
66cb1910 | 784 | struct cache *cache = mg->cache; |
c6b4fcba | 785 | free_migration(mg); |
66cb1910 | 786 | dec_nr_migrations(cache); |
c6b4fcba JT |
787 | } |
788 | ||
789 | static void migration_failure(struct dm_cache_migration *mg) | |
790 | { | |
791 | struct cache *cache = mg->cache; | |
792 | ||
793 | if (mg->writeback) { | |
794 | DMWARN_LIMIT("writeback failed; couldn't copy block"); | |
795 | set_dirty(cache, mg->old_oblock, mg->cblock); | |
796 | cell_defer(cache, mg->old_ocell, false); | |
797 | ||
798 | } else if (mg->demote) { | |
799 | DMWARN_LIMIT("demotion failed; couldn't copy block"); | |
800 | policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); | |
801 | ||
80f659f3 | 802 | cell_defer(cache, mg->old_ocell, mg->promote ? false : true); |
c6b4fcba | 803 | if (mg->promote) |
80f659f3 | 804 | cell_defer(cache, mg->new_ocell, true); |
c6b4fcba JT |
805 | } else { |
806 | DMWARN_LIMIT("promotion failed; couldn't copy block"); | |
807 | policy_remove_mapping(cache->policy, mg->new_oblock); | |
80f659f3 | 808 | cell_defer(cache, mg->new_ocell, true); |
c6b4fcba JT |
809 | } |
810 | ||
811 | cleanup_migration(mg); | |
812 | } | |
813 | ||
814 | static void migration_success_pre_commit(struct dm_cache_migration *mg) | |
815 | { | |
816 | unsigned long flags; | |
817 | struct cache *cache = mg->cache; | |
818 | ||
819 | if (mg->writeback) { | |
820 | cell_defer(cache, mg->old_ocell, false); | |
821 | clear_dirty(cache, mg->old_oblock, mg->cblock); | |
822 | cleanup_migration(mg); | |
823 | return; | |
824 | ||
825 | } else if (mg->demote) { | |
826 | if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) { | |
827 | DMWARN_LIMIT("demotion failed; couldn't update on disk metadata"); | |
828 | policy_force_mapping(cache->policy, mg->new_oblock, | |
829 | mg->old_oblock); | |
830 | if (mg->promote) | |
831 | cell_defer(cache, mg->new_ocell, true); | |
832 | cleanup_migration(mg); | |
833 | return; | |
834 | } | |
835 | } else { | |
836 | if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) { | |
837 | DMWARN_LIMIT("promotion failed; couldn't update on disk metadata"); | |
838 | policy_remove_mapping(cache->policy, mg->new_oblock); | |
839 | cleanup_migration(mg); | |
840 | return; | |
841 | } | |
842 | } | |
843 | ||
844 | spin_lock_irqsave(&cache->lock, flags); | |
845 | list_add_tail(&mg->list, &cache->need_commit_migrations); | |
846 | cache->commit_requested = true; | |
847 | spin_unlock_irqrestore(&cache->lock, flags); | |
848 | } | |
849 | ||
850 | static void migration_success_post_commit(struct dm_cache_migration *mg) | |
851 | { | |
852 | unsigned long flags; | |
853 | struct cache *cache = mg->cache; | |
854 | ||
855 | if (mg->writeback) { | |
856 | DMWARN("writeback unexpectedly triggered commit"); | |
857 | return; | |
858 | ||
859 | } else if (mg->demote) { | |
80f659f3 | 860 | cell_defer(cache, mg->old_ocell, mg->promote ? false : true); |
c6b4fcba JT |
861 | |
862 | if (mg->promote) { | |
863 | mg->demote = false; | |
864 | ||
865 | spin_lock_irqsave(&cache->lock, flags); | |
866 | list_add_tail(&mg->list, &cache->quiesced_migrations); | |
867 | spin_unlock_irqrestore(&cache->lock, flags); | |
868 | ||
869 | } else | |
870 | cleanup_migration(mg); | |
871 | ||
872 | } else { | |
c9d28d5d JT |
873 | if (mg->requeue_holder) |
874 | cell_defer(cache, mg->new_ocell, true); | |
875 | else { | |
876 | bio_endio(mg->new_ocell->holder, 0); | |
877 | cell_defer(cache, mg->new_ocell, false); | |
878 | } | |
c6b4fcba JT |
879 | clear_dirty(cache, mg->new_oblock, mg->cblock); |
880 | cleanup_migration(mg); | |
881 | } | |
882 | } | |
883 | ||
884 | static void copy_complete(int read_err, unsigned long write_err, void *context) | |
885 | { | |
886 | unsigned long flags; | |
887 | struct dm_cache_migration *mg = (struct dm_cache_migration *) context; | |
888 | struct cache *cache = mg->cache; | |
889 | ||
890 | if (read_err || write_err) | |
891 | mg->err = true; | |
892 | ||
893 | spin_lock_irqsave(&cache->lock, flags); | |
894 | list_add_tail(&mg->list, &cache->completed_migrations); | |
895 | spin_unlock_irqrestore(&cache->lock, flags); | |
896 | ||
897 | wake_worker(cache); | |
898 | } | |
899 | ||
900 | static void issue_copy_real(struct dm_cache_migration *mg) | |
901 | { | |
902 | int r; | |
903 | struct dm_io_region o_region, c_region; | |
904 | struct cache *cache = mg->cache; | |
905 | ||
906 | o_region.bdev = cache->origin_dev->bdev; | |
907 | o_region.count = cache->sectors_per_block; | |
908 | ||
909 | c_region.bdev = cache->cache_dev->bdev; | |
910 | c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block; | |
911 | c_region.count = cache->sectors_per_block; | |
912 | ||
913 | if (mg->writeback || mg->demote) { | |
914 | /* demote */ | |
915 | o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block; | |
916 | r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg); | |
917 | } else { | |
918 | /* promote */ | |
919 | o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block; | |
920 | r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg); | |
921 | } | |
922 | ||
2c2263c9 HM |
923 | if (r < 0) { |
924 | DMERR_LIMIT("issuing migration failed"); | |
c6b4fcba | 925 | migration_failure(mg); |
2c2263c9 | 926 | } |
c6b4fcba JT |
927 | } |
928 | ||
c9d28d5d JT |
929 | static void overwrite_endio(struct bio *bio, int err) |
930 | { | |
931 | struct dm_cache_migration *mg = bio->bi_private; | |
932 | struct cache *cache = mg->cache; | |
933 | size_t pb_data_size = get_per_bio_data_size(cache); | |
934 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
935 | unsigned long flags; | |
936 | ||
937 | if (err) | |
938 | mg->err = true; | |
939 | ||
940 | spin_lock_irqsave(&cache->lock, flags); | |
941 | list_add_tail(&mg->list, &cache->completed_migrations); | |
942 | dm_unhook_bio(&pb->hook_info, bio); | |
943 | mg->requeue_holder = false; | |
944 | spin_unlock_irqrestore(&cache->lock, flags); | |
945 | ||
946 | wake_worker(cache); | |
947 | } | |
948 | ||
949 | static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio) | |
950 | { | |
951 | size_t pb_data_size = get_per_bio_data_size(mg->cache); | |
952 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
953 | ||
954 | dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg); | |
955 | remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock); | |
956 | generic_make_request(bio); | |
957 | } | |
958 | ||
959 | static bool bio_writes_complete_block(struct cache *cache, struct bio *bio) | |
960 | { | |
961 | return (bio_data_dir(bio) == WRITE) && | |
962 | (bio->bi_size == (cache->sectors_per_block << SECTOR_SHIFT)); | |
963 | } | |
964 | ||
c6b4fcba JT |
965 | static void avoid_copy(struct dm_cache_migration *mg) |
966 | { | |
967 | atomic_inc(&mg->cache->stats.copies_avoided); | |
968 | migration_success_pre_commit(mg); | |
969 | } | |
970 | ||
971 | static void issue_copy(struct dm_cache_migration *mg) | |
972 | { | |
973 | bool avoid; | |
974 | struct cache *cache = mg->cache; | |
975 | ||
976 | if (mg->writeback || mg->demote) | |
977 | avoid = !is_dirty(cache, mg->cblock) || | |
978 | is_discarded_oblock(cache, mg->old_oblock); | |
c9d28d5d JT |
979 | else { |
980 | struct bio *bio = mg->new_ocell->holder; | |
981 | ||
c6b4fcba JT |
982 | avoid = is_discarded_oblock(cache, mg->new_oblock); |
983 | ||
c9d28d5d JT |
984 | if (!avoid && bio_writes_complete_block(cache, bio)) { |
985 | issue_overwrite(mg, bio); | |
986 | return; | |
987 | } | |
988 | } | |
989 | ||
c6b4fcba JT |
990 | avoid ? avoid_copy(mg) : issue_copy_real(mg); |
991 | } | |
992 | ||
993 | static void complete_migration(struct dm_cache_migration *mg) | |
994 | { | |
995 | if (mg->err) | |
996 | migration_failure(mg); | |
997 | else | |
998 | migration_success_pre_commit(mg); | |
999 | } | |
1000 | ||
1001 | static void process_migrations(struct cache *cache, struct list_head *head, | |
1002 | void (*fn)(struct dm_cache_migration *)) | |
1003 | { | |
1004 | unsigned long flags; | |
1005 | struct list_head list; | |
1006 | struct dm_cache_migration *mg, *tmp; | |
1007 | ||
1008 | INIT_LIST_HEAD(&list); | |
1009 | spin_lock_irqsave(&cache->lock, flags); | |
1010 | list_splice_init(head, &list); | |
1011 | spin_unlock_irqrestore(&cache->lock, flags); | |
1012 | ||
1013 | list_for_each_entry_safe(mg, tmp, &list, list) | |
1014 | fn(mg); | |
1015 | } | |
1016 | ||
1017 | static void __queue_quiesced_migration(struct dm_cache_migration *mg) | |
1018 | { | |
1019 | list_add_tail(&mg->list, &mg->cache->quiesced_migrations); | |
1020 | } | |
1021 | ||
1022 | static void queue_quiesced_migration(struct dm_cache_migration *mg) | |
1023 | { | |
1024 | unsigned long flags; | |
1025 | struct cache *cache = mg->cache; | |
1026 | ||
1027 | spin_lock_irqsave(&cache->lock, flags); | |
1028 | __queue_quiesced_migration(mg); | |
1029 | spin_unlock_irqrestore(&cache->lock, flags); | |
1030 | ||
1031 | wake_worker(cache); | |
1032 | } | |
1033 | ||
1034 | static void queue_quiesced_migrations(struct cache *cache, struct list_head *work) | |
1035 | { | |
1036 | unsigned long flags; | |
1037 | struct dm_cache_migration *mg, *tmp; | |
1038 | ||
1039 | spin_lock_irqsave(&cache->lock, flags); | |
1040 | list_for_each_entry_safe(mg, tmp, work, list) | |
1041 | __queue_quiesced_migration(mg); | |
1042 | spin_unlock_irqrestore(&cache->lock, flags); | |
1043 | ||
1044 | wake_worker(cache); | |
1045 | } | |
1046 | ||
1047 | static void check_for_quiesced_migrations(struct cache *cache, | |
1048 | struct per_bio_data *pb) | |
1049 | { | |
1050 | struct list_head work; | |
1051 | ||
1052 | if (!pb->all_io_entry) | |
1053 | return; | |
1054 | ||
1055 | INIT_LIST_HEAD(&work); | |
1056 | if (pb->all_io_entry) | |
1057 | dm_deferred_entry_dec(pb->all_io_entry, &work); | |
1058 | ||
1059 | if (!list_empty(&work)) | |
1060 | queue_quiesced_migrations(cache, &work); | |
1061 | } | |
1062 | ||
1063 | static void quiesce_migration(struct dm_cache_migration *mg) | |
1064 | { | |
1065 | if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list)) | |
1066 | queue_quiesced_migration(mg); | |
1067 | } | |
1068 | ||
1069 | static void promote(struct cache *cache, struct prealloc *structs, | |
1070 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1071 | struct dm_bio_prison_cell *cell) | |
1072 | { | |
1073 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1074 | ||
1075 | mg->err = false; | |
1076 | mg->writeback = false; | |
1077 | mg->demote = false; | |
1078 | mg->promote = true; | |
c9d28d5d | 1079 | mg->requeue_holder = true; |
c6b4fcba JT |
1080 | mg->cache = cache; |
1081 | mg->new_oblock = oblock; | |
1082 | mg->cblock = cblock; | |
1083 | mg->old_ocell = NULL; | |
1084 | mg->new_ocell = cell; | |
1085 | mg->start_jiffies = jiffies; | |
1086 | ||
1087 | inc_nr_migrations(cache); | |
1088 | quiesce_migration(mg); | |
1089 | } | |
1090 | ||
1091 | static void writeback(struct cache *cache, struct prealloc *structs, | |
1092 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1093 | struct dm_bio_prison_cell *cell) | |
1094 | { | |
1095 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1096 | ||
1097 | mg->err = false; | |
1098 | mg->writeback = true; | |
1099 | mg->demote = false; | |
1100 | mg->promote = false; | |
c9d28d5d | 1101 | mg->requeue_holder = true; |
c6b4fcba JT |
1102 | mg->cache = cache; |
1103 | mg->old_oblock = oblock; | |
1104 | mg->cblock = cblock; | |
1105 | mg->old_ocell = cell; | |
1106 | mg->new_ocell = NULL; | |
1107 | mg->start_jiffies = jiffies; | |
1108 | ||
1109 | inc_nr_migrations(cache); | |
1110 | quiesce_migration(mg); | |
1111 | } | |
1112 | ||
1113 | static void demote_then_promote(struct cache *cache, struct prealloc *structs, | |
1114 | dm_oblock_t old_oblock, dm_oblock_t new_oblock, | |
1115 | dm_cblock_t cblock, | |
1116 | struct dm_bio_prison_cell *old_ocell, | |
1117 | struct dm_bio_prison_cell *new_ocell) | |
1118 | { | |
1119 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1120 | ||
1121 | mg->err = false; | |
1122 | mg->writeback = false; | |
1123 | mg->demote = true; | |
1124 | mg->promote = true; | |
c9d28d5d | 1125 | mg->requeue_holder = true; |
c6b4fcba JT |
1126 | mg->cache = cache; |
1127 | mg->old_oblock = old_oblock; | |
1128 | mg->new_oblock = new_oblock; | |
1129 | mg->cblock = cblock; | |
1130 | mg->old_ocell = old_ocell; | |
1131 | mg->new_ocell = new_ocell; | |
1132 | mg->start_jiffies = jiffies; | |
1133 | ||
1134 | inc_nr_migrations(cache); | |
1135 | quiesce_migration(mg); | |
1136 | } | |
1137 | ||
1138 | /*---------------------------------------------------------------- | |
1139 | * bio processing | |
1140 | *--------------------------------------------------------------*/ | |
1141 | static void defer_bio(struct cache *cache, struct bio *bio) | |
1142 | { | |
1143 | unsigned long flags; | |
1144 | ||
1145 | spin_lock_irqsave(&cache->lock, flags); | |
1146 | bio_list_add(&cache->deferred_bios, bio); | |
1147 | spin_unlock_irqrestore(&cache->lock, flags); | |
1148 | ||
1149 | wake_worker(cache); | |
1150 | } | |
1151 | ||
1152 | static void process_flush_bio(struct cache *cache, struct bio *bio) | |
1153 | { | |
19b0092e MS |
1154 | size_t pb_data_size = get_per_bio_data_size(cache); |
1155 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
1156 | |
1157 | BUG_ON(bio->bi_size); | |
1158 | if (!pb->req_nr) | |
1159 | remap_to_origin(cache, bio); | |
1160 | else | |
1161 | remap_to_cache(cache, bio, 0); | |
1162 | ||
1163 | issue(cache, bio); | |
1164 | } | |
1165 | ||
1166 | /* | |
1167 | * People generally discard large parts of a device, eg, the whole device | |
1168 | * when formatting. Splitting these large discards up into cache block | |
1169 | * sized ios and then quiescing (always neccessary for discard) takes too | |
1170 | * long. | |
1171 | * | |
1172 | * We keep it simple, and allow any size of discard to come in, and just | |
1173 | * mark off blocks on the discard bitset. No passdown occurs! | |
1174 | * | |
1175 | * To implement passdown we need to change the bio_prison such that a cell | |
1176 | * can have a key that spans many blocks. | |
1177 | */ | |
1178 | static void process_discard_bio(struct cache *cache, struct bio *bio) | |
1179 | { | |
1180 | dm_block_t start_block = dm_sector_div_up(bio->bi_sector, | |
1181 | cache->discard_block_size); | |
1182 | dm_block_t end_block = bio->bi_sector + bio_sectors(bio); | |
1183 | dm_block_t b; | |
1184 | ||
414dd67d | 1185 | end_block = block_div(end_block, cache->discard_block_size); |
c6b4fcba JT |
1186 | |
1187 | for (b = start_block; b < end_block; b++) | |
1188 | set_discard(cache, to_dblock(b)); | |
1189 | ||
1190 | bio_endio(bio, 0); | |
1191 | } | |
1192 | ||
1193 | static bool spare_migration_bandwidth(struct cache *cache) | |
1194 | { | |
1195 | sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) * | |
1196 | cache->sectors_per_block; | |
1197 | return current_volume < cache->migration_threshold; | |
1198 | } | |
1199 | ||
1200 | static bool is_writethrough_io(struct cache *cache, struct bio *bio, | |
1201 | dm_cblock_t cblock) | |
1202 | { | |
1203 | return bio_data_dir(bio) == WRITE && | |
1204 | cache->features.write_through && !is_dirty(cache, cblock); | |
1205 | } | |
1206 | ||
1207 | static void inc_hit_counter(struct cache *cache, struct bio *bio) | |
1208 | { | |
1209 | atomic_inc(bio_data_dir(bio) == READ ? | |
1210 | &cache->stats.read_hit : &cache->stats.write_hit); | |
1211 | } | |
1212 | ||
1213 | static void inc_miss_counter(struct cache *cache, struct bio *bio) | |
1214 | { | |
1215 | atomic_inc(bio_data_dir(bio) == READ ? | |
1216 | &cache->stats.read_miss : &cache->stats.write_miss); | |
1217 | } | |
1218 | ||
1219 | static void process_bio(struct cache *cache, struct prealloc *structs, | |
1220 | struct bio *bio) | |
1221 | { | |
1222 | int r; | |
1223 | bool release_cell = true; | |
1224 | dm_oblock_t block = get_bio_block(cache, bio); | |
1225 | struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell; | |
1226 | struct policy_result lookup_result; | |
19b0092e MS |
1227 | size_t pb_data_size = get_per_bio_data_size(cache); |
1228 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
1229 | bool discarded_block = is_discarded_oblock(cache, block); |
1230 | bool can_migrate = discarded_block || spare_migration_bandwidth(cache); | |
1231 | ||
1232 | /* | |
1233 | * Check to see if that block is currently migrating. | |
1234 | */ | |
1235 | cell_prealloc = prealloc_get_cell(structs); | |
1236 | r = bio_detain(cache, block, bio, cell_prealloc, | |
1237 | (cell_free_fn) prealloc_put_cell, | |
1238 | structs, &new_ocell); | |
1239 | if (r > 0) | |
1240 | return; | |
1241 | ||
1242 | r = policy_map(cache->policy, block, true, can_migrate, discarded_block, | |
1243 | bio, &lookup_result); | |
1244 | ||
1245 | if (r == -EWOULDBLOCK) | |
1246 | /* migration has been denied */ | |
1247 | lookup_result.op = POLICY_MISS; | |
1248 | ||
1249 | switch (lookup_result.op) { | |
1250 | case POLICY_HIT: | |
1251 | inc_hit_counter(cache, bio); | |
1252 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
1253 | ||
e2e74d61 JT |
1254 | if (is_writethrough_io(cache, bio, lookup_result.cblock)) |
1255 | remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); | |
1256 | else | |
c6b4fcba JT |
1257 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); |
1258 | ||
1259 | issue(cache, bio); | |
1260 | break; | |
1261 | ||
1262 | case POLICY_MISS: | |
1263 | inc_miss_counter(cache, bio); | |
1264 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
e2e74d61 JT |
1265 | remap_to_origin_clear_discard(cache, bio, block); |
1266 | issue(cache, bio); | |
c6b4fcba JT |
1267 | break; |
1268 | ||
1269 | case POLICY_NEW: | |
1270 | atomic_inc(&cache->stats.promotion); | |
1271 | promote(cache, structs, block, lookup_result.cblock, new_ocell); | |
1272 | release_cell = false; | |
1273 | break; | |
1274 | ||
1275 | case POLICY_REPLACE: | |
1276 | cell_prealloc = prealloc_get_cell(structs); | |
1277 | r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc, | |
1278 | (cell_free_fn) prealloc_put_cell, | |
1279 | structs, &old_ocell); | |
1280 | if (r > 0) { | |
1281 | /* | |
1282 | * We have to be careful to avoid lock inversion of | |
1283 | * the cells. So we back off, and wait for the | |
1284 | * old_ocell to become free. | |
1285 | */ | |
1286 | policy_force_mapping(cache->policy, block, | |
1287 | lookup_result.old_oblock); | |
1288 | atomic_inc(&cache->stats.cache_cell_clash); | |
1289 | break; | |
1290 | } | |
1291 | atomic_inc(&cache->stats.demotion); | |
1292 | atomic_inc(&cache->stats.promotion); | |
1293 | ||
1294 | demote_then_promote(cache, structs, lookup_result.old_oblock, | |
1295 | block, lookup_result.cblock, | |
1296 | old_ocell, new_ocell); | |
1297 | release_cell = false; | |
1298 | break; | |
1299 | ||
1300 | default: | |
1301 | DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__, | |
1302 | (unsigned) lookup_result.op); | |
1303 | bio_io_error(bio); | |
1304 | } | |
1305 | ||
1306 | if (release_cell) | |
1307 | cell_defer(cache, new_ocell, false); | |
1308 | } | |
1309 | ||
1310 | static int need_commit_due_to_time(struct cache *cache) | |
1311 | { | |
1312 | return jiffies < cache->last_commit_jiffies || | |
1313 | jiffies > cache->last_commit_jiffies + COMMIT_PERIOD; | |
1314 | } | |
1315 | ||
1316 | static int commit_if_needed(struct cache *cache) | |
1317 | { | |
ffcbcb67 HM |
1318 | int r = 0; |
1319 | ||
1320 | if ((cache->commit_requested || need_commit_due_to_time(cache)) && | |
1321 | dm_cache_changed_this_transaction(cache->cmd)) { | |
c6b4fcba | 1322 | atomic_inc(&cache->stats.commit_count); |
c6b4fcba | 1323 | cache->commit_requested = false; |
ffcbcb67 HM |
1324 | r = dm_cache_commit(cache->cmd, false); |
1325 | cache->last_commit_jiffies = jiffies; | |
c6b4fcba JT |
1326 | } |
1327 | ||
ffcbcb67 | 1328 | return r; |
c6b4fcba JT |
1329 | } |
1330 | ||
1331 | static void process_deferred_bios(struct cache *cache) | |
1332 | { | |
1333 | unsigned long flags; | |
1334 | struct bio_list bios; | |
1335 | struct bio *bio; | |
1336 | struct prealloc structs; | |
1337 | ||
1338 | memset(&structs, 0, sizeof(structs)); | |
1339 | bio_list_init(&bios); | |
1340 | ||
1341 | spin_lock_irqsave(&cache->lock, flags); | |
1342 | bio_list_merge(&bios, &cache->deferred_bios); | |
1343 | bio_list_init(&cache->deferred_bios); | |
1344 | spin_unlock_irqrestore(&cache->lock, flags); | |
1345 | ||
1346 | while (!bio_list_empty(&bios)) { | |
1347 | /* | |
1348 | * If we've got no free migration structs, and processing | |
1349 | * this bio might require one, we pause until there are some | |
1350 | * prepared mappings to process. | |
1351 | */ | |
1352 | if (prealloc_data_structs(cache, &structs)) { | |
1353 | spin_lock_irqsave(&cache->lock, flags); | |
1354 | bio_list_merge(&cache->deferred_bios, &bios); | |
1355 | spin_unlock_irqrestore(&cache->lock, flags); | |
1356 | break; | |
1357 | } | |
1358 | ||
1359 | bio = bio_list_pop(&bios); | |
1360 | ||
1361 | if (bio->bi_rw & REQ_FLUSH) | |
1362 | process_flush_bio(cache, bio); | |
1363 | else if (bio->bi_rw & REQ_DISCARD) | |
1364 | process_discard_bio(cache, bio); | |
1365 | else | |
1366 | process_bio(cache, &structs, bio); | |
1367 | } | |
1368 | ||
1369 | prealloc_free_structs(cache, &structs); | |
1370 | } | |
1371 | ||
1372 | static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) | |
1373 | { | |
1374 | unsigned long flags; | |
1375 | struct bio_list bios; | |
1376 | struct bio *bio; | |
1377 | ||
1378 | bio_list_init(&bios); | |
1379 | ||
1380 | spin_lock_irqsave(&cache->lock, flags); | |
1381 | bio_list_merge(&bios, &cache->deferred_flush_bios); | |
1382 | bio_list_init(&cache->deferred_flush_bios); | |
1383 | spin_unlock_irqrestore(&cache->lock, flags); | |
1384 | ||
1385 | while ((bio = bio_list_pop(&bios))) | |
1386 | submit_bios ? generic_make_request(bio) : bio_io_error(bio); | |
1387 | } | |
1388 | ||
e2e74d61 JT |
1389 | static void process_deferred_writethrough_bios(struct cache *cache) |
1390 | { | |
1391 | unsigned long flags; | |
1392 | struct bio_list bios; | |
1393 | struct bio *bio; | |
1394 | ||
1395 | bio_list_init(&bios); | |
1396 | ||
1397 | spin_lock_irqsave(&cache->lock, flags); | |
1398 | bio_list_merge(&bios, &cache->deferred_writethrough_bios); | |
1399 | bio_list_init(&cache->deferred_writethrough_bios); | |
1400 | spin_unlock_irqrestore(&cache->lock, flags); | |
1401 | ||
1402 | while ((bio = bio_list_pop(&bios))) | |
1403 | generic_make_request(bio); | |
1404 | } | |
1405 | ||
c6b4fcba JT |
1406 | static void writeback_some_dirty_blocks(struct cache *cache) |
1407 | { | |
1408 | int r = 0; | |
1409 | dm_oblock_t oblock; | |
1410 | dm_cblock_t cblock; | |
1411 | struct prealloc structs; | |
1412 | struct dm_bio_prison_cell *old_ocell; | |
1413 | ||
1414 | memset(&structs, 0, sizeof(structs)); | |
1415 | ||
1416 | while (spare_migration_bandwidth(cache)) { | |
1417 | if (prealloc_data_structs(cache, &structs)) | |
1418 | break; | |
1419 | ||
1420 | r = policy_writeback_work(cache->policy, &oblock, &cblock); | |
1421 | if (r) | |
1422 | break; | |
1423 | ||
1424 | r = get_cell(cache, oblock, &structs, &old_ocell); | |
1425 | if (r) { | |
1426 | policy_set_dirty(cache->policy, oblock); | |
1427 | break; | |
1428 | } | |
1429 | ||
1430 | writeback(cache, &structs, oblock, cblock, old_ocell); | |
1431 | } | |
1432 | ||
1433 | prealloc_free_structs(cache, &structs); | |
1434 | } | |
1435 | ||
1436 | /*---------------------------------------------------------------- | |
1437 | * Main worker loop | |
1438 | *--------------------------------------------------------------*/ | |
66cb1910 | 1439 | static bool is_quiescing(struct cache *cache) |
c6b4fcba | 1440 | { |
238f8363 | 1441 | return atomic_read(&cache->quiescing); |
c6b4fcba JT |
1442 | } |
1443 | ||
66cb1910 JT |
1444 | static void ack_quiescing(struct cache *cache) |
1445 | { | |
1446 | if (is_quiescing(cache)) { | |
1447 | atomic_inc(&cache->quiescing_ack); | |
1448 | wake_up(&cache->quiescing_wait); | |
1449 | } | |
1450 | } | |
1451 | ||
1452 | static void wait_for_quiescing_ack(struct cache *cache) | |
1453 | { | |
1454 | wait_event(cache->quiescing_wait, atomic_read(&cache->quiescing_ack)); | |
1455 | } | |
1456 | ||
1457 | static void start_quiescing(struct cache *cache) | |
c6b4fcba | 1458 | { |
238f8363 | 1459 | atomic_inc(&cache->quiescing); |
66cb1910 | 1460 | wait_for_quiescing_ack(cache); |
c6b4fcba JT |
1461 | } |
1462 | ||
66cb1910 | 1463 | static void stop_quiescing(struct cache *cache) |
c6b4fcba | 1464 | { |
238f8363 | 1465 | atomic_set(&cache->quiescing, 0); |
66cb1910 | 1466 | atomic_set(&cache->quiescing_ack, 0); |
c6b4fcba JT |
1467 | } |
1468 | ||
1469 | static void wait_for_migrations(struct cache *cache) | |
1470 | { | |
1471 | wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations)); | |
1472 | } | |
1473 | ||
1474 | static void stop_worker(struct cache *cache) | |
1475 | { | |
1476 | cancel_delayed_work(&cache->waker); | |
1477 | flush_workqueue(cache->wq); | |
1478 | } | |
1479 | ||
1480 | static void requeue_deferred_io(struct cache *cache) | |
1481 | { | |
1482 | struct bio *bio; | |
1483 | struct bio_list bios; | |
1484 | ||
1485 | bio_list_init(&bios); | |
1486 | bio_list_merge(&bios, &cache->deferred_bios); | |
1487 | bio_list_init(&cache->deferred_bios); | |
1488 | ||
1489 | while ((bio = bio_list_pop(&bios))) | |
1490 | bio_endio(bio, DM_ENDIO_REQUEUE); | |
1491 | } | |
1492 | ||
1493 | static int more_work(struct cache *cache) | |
1494 | { | |
1495 | if (is_quiescing(cache)) | |
1496 | return !list_empty(&cache->quiesced_migrations) || | |
1497 | !list_empty(&cache->completed_migrations) || | |
1498 | !list_empty(&cache->need_commit_migrations); | |
1499 | else | |
1500 | return !bio_list_empty(&cache->deferred_bios) || | |
1501 | !bio_list_empty(&cache->deferred_flush_bios) || | |
e2e74d61 | 1502 | !bio_list_empty(&cache->deferred_writethrough_bios) || |
c6b4fcba JT |
1503 | !list_empty(&cache->quiesced_migrations) || |
1504 | !list_empty(&cache->completed_migrations) || | |
1505 | !list_empty(&cache->need_commit_migrations); | |
1506 | } | |
1507 | ||
1508 | static void do_worker(struct work_struct *ws) | |
1509 | { | |
1510 | struct cache *cache = container_of(ws, struct cache, worker); | |
1511 | ||
1512 | do { | |
66cb1910 JT |
1513 | if (!is_quiescing(cache)) { |
1514 | writeback_some_dirty_blocks(cache); | |
1515 | process_deferred_writethrough_bios(cache); | |
c6b4fcba | 1516 | process_deferred_bios(cache); |
66cb1910 | 1517 | } |
c6b4fcba JT |
1518 | |
1519 | process_migrations(cache, &cache->quiesced_migrations, issue_copy); | |
1520 | process_migrations(cache, &cache->completed_migrations, complete_migration); | |
1521 | ||
c6b4fcba JT |
1522 | if (commit_if_needed(cache)) { |
1523 | process_deferred_flush_bios(cache, false); | |
1524 | ||
1525 | /* | |
1526 | * FIXME: rollback metadata or just go into a | |
1527 | * failure mode and error everything | |
1528 | */ | |
1529 | } else { | |
1530 | process_deferred_flush_bios(cache, true); | |
1531 | process_migrations(cache, &cache->need_commit_migrations, | |
1532 | migration_success_post_commit); | |
1533 | } | |
66cb1910 JT |
1534 | |
1535 | ack_quiescing(cache); | |
1536 | ||
c6b4fcba JT |
1537 | } while (more_work(cache)); |
1538 | } | |
1539 | ||
1540 | /* | |
1541 | * We want to commit periodically so that not too much | |
1542 | * unwritten metadata builds up. | |
1543 | */ | |
1544 | static void do_waker(struct work_struct *ws) | |
1545 | { | |
1546 | struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker); | |
f8350daf | 1547 | policy_tick(cache->policy); |
c6b4fcba JT |
1548 | wake_worker(cache); |
1549 | queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); | |
1550 | } | |
1551 | ||
1552 | /*----------------------------------------------------------------*/ | |
1553 | ||
1554 | static int is_congested(struct dm_dev *dev, int bdi_bits) | |
1555 | { | |
1556 | struct request_queue *q = bdev_get_queue(dev->bdev); | |
1557 | return bdi_congested(&q->backing_dev_info, bdi_bits); | |
1558 | } | |
1559 | ||
1560 | static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits) | |
1561 | { | |
1562 | struct cache *cache = container_of(cb, struct cache, callbacks); | |
1563 | ||
1564 | return is_congested(cache->origin_dev, bdi_bits) || | |
1565 | is_congested(cache->cache_dev, bdi_bits); | |
1566 | } | |
1567 | ||
1568 | /*---------------------------------------------------------------- | |
1569 | * Target methods | |
1570 | *--------------------------------------------------------------*/ | |
1571 | ||
1572 | /* | |
1573 | * This function gets called on the error paths of the constructor, so we | |
1574 | * have to cope with a partially initialised struct. | |
1575 | */ | |
1576 | static void destroy(struct cache *cache) | |
1577 | { | |
1578 | unsigned i; | |
1579 | ||
1580 | if (cache->next_migration) | |
1581 | mempool_free(cache->next_migration, cache->migration_pool); | |
1582 | ||
1583 | if (cache->migration_pool) | |
1584 | mempool_destroy(cache->migration_pool); | |
1585 | ||
1586 | if (cache->all_io_ds) | |
1587 | dm_deferred_set_destroy(cache->all_io_ds); | |
1588 | ||
1589 | if (cache->prison) | |
1590 | dm_bio_prison_destroy(cache->prison); | |
1591 | ||
1592 | if (cache->wq) | |
1593 | destroy_workqueue(cache->wq); | |
1594 | ||
1595 | if (cache->dirty_bitset) | |
1596 | free_bitset(cache->dirty_bitset); | |
1597 | ||
1598 | if (cache->discard_bitset) | |
1599 | free_bitset(cache->discard_bitset); | |
1600 | ||
1601 | if (cache->copier) | |
1602 | dm_kcopyd_client_destroy(cache->copier); | |
1603 | ||
1604 | if (cache->cmd) | |
1605 | dm_cache_metadata_close(cache->cmd); | |
1606 | ||
1607 | if (cache->metadata_dev) | |
1608 | dm_put_device(cache->ti, cache->metadata_dev); | |
1609 | ||
1610 | if (cache->origin_dev) | |
1611 | dm_put_device(cache->ti, cache->origin_dev); | |
1612 | ||
1613 | if (cache->cache_dev) | |
1614 | dm_put_device(cache->ti, cache->cache_dev); | |
1615 | ||
1616 | if (cache->policy) | |
1617 | dm_cache_policy_destroy(cache->policy); | |
1618 | ||
1619 | for (i = 0; i < cache->nr_ctr_args ; i++) | |
1620 | kfree(cache->ctr_args[i]); | |
1621 | kfree(cache->ctr_args); | |
1622 | ||
1623 | kfree(cache); | |
1624 | } | |
1625 | ||
1626 | static void cache_dtr(struct dm_target *ti) | |
1627 | { | |
1628 | struct cache *cache = ti->private; | |
1629 | ||
1630 | destroy(cache); | |
1631 | } | |
1632 | ||
1633 | static sector_t get_dev_size(struct dm_dev *dev) | |
1634 | { | |
1635 | return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT; | |
1636 | } | |
1637 | ||
1638 | /*----------------------------------------------------------------*/ | |
1639 | ||
1640 | /* | |
1641 | * Construct a cache device mapping. | |
1642 | * | |
1643 | * cache <metadata dev> <cache dev> <origin dev> <block size> | |
1644 | * <#feature args> [<feature arg>]* | |
1645 | * <policy> <#policy args> [<policy arg>]* | |
1646 | * | |
1647 | * metadata dev : fast device holding the persistent metadata | |
1648 | * cache dev : fast device holding cached data blocks | |
1649 | * origin dev : slow device holding original data blocks | |
1650 | * block size : cache unit size in sectors | |
1651 | * | |
1652 | * #feature args : number of feature arguments passed | |
1653 | * feature args : writethrough. (The default is writeback.) | |
1654 | * | |
1655 | * policy : the replacement policy to use | |
1656 | * #policy args : an even number of policy arguments corresponding | |
1657 | * to key/value pairs passed to the policy | |
1658 | * policy args : key/value pairs passed to the policy | |
1659 | * E.g. 'sequential_threshold 1024' | |
1660 | * See cache-policies.txt for details. | |
1661 | * | |
1662 | * Optional feature arguments are: | |
1663 | * writethrough : write through caching that prohibits cache block | |
1664 | * content from being different from origin block content. | |
1665 | * Without this argument, the default behaviour is to write | |
1666 | * back cache block contents later for performance reasons, | |
1667 | * so they may differ from the corresponding origin blocks. | |
1668 | */ | |
1669 | struct cache_args { | |
1670 | struct dm_target *ti; | |
1671 | ||
1672 | struct dm_dev *metadata_dev; | |
1673 | ||
1674 | struct dm_dev *cache_dev; | |
1675 | sector_t cache_sectors; | |
1676 | ||
1677 | struct dm_dev *origin_dev; | |
1678 | sector_t origin_sectors; | |
1679 | ||
1680 | uint32_t block_size; | |
1681 | ||
1682 | const char *policy_name; | |
1683 | int policy_argc; | |
1684 | const char **policy_argv; | |
1685 | ||
1686 | struct cache_features features; | |
1687 | }; | |
1688 | ||
1689 | static void destroy_cache_args(struct cache_args *ca) | |
1690 | { | |
1691 | if (ca->metadata_dev) | |
1692 | dm_put_device(ca->ti, ca->metadata_dev); | |
1693 | ||
1694 | if (ca->cache_dev) | |
1695 | dm_put_device(ca->ti, ca->cache_dev); | |
1696 | ||
1697 | if (ca->origin_dev) | |
1698 | dm_put_device(ca->ti, ca->origin_dev); | |
1699 | ||
1700 | kfree(ca); | |
1701 | } | |
1702 | ||
1703 | static bool at_least_one_arg(struct dm_arg_set *as, char **error) | |
1704 | { | |
1705 | if (!as->argc) { | |
1706 | *error = "Insufficient args"; | |
1707 | return false; | |
1708 | } | |
1709 | ||
1710 | return true; | |
1711 | } | |
1712 | ||
1713 | static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1714 | char **error) | |
1715 | { | |
1716 | int r; | |
1717 | sector_t metadata_dev_size; | |
1718 | char b[BDEVNAME_SIZE]; | |
1719 | ||
1720 | if (!at_least_one_arg(as, error)) | |
1721 | return -EINVAL; | |
1722 | ||
1723 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1724 | &ca->metadata_dev); | |
1725 | if (r) { | |
1726 | *error = "Error opening metadata device"; | |
1727 | return r; | |
1728 | } | |
1729 | ||
1730 | metadata_dev_size = get_dev_size(ca->metadata_dev); | |
1731 | if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING) | |
1732 | DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", | |
1733 | bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS); | |
1734 | ||
1735 | return 0; | |
1736 | } | |
1737 | ||
1738 | static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1739 | char **error) | |
1740 | { | |
1741 | int r; | |
1742 | ||
1743 | if (!at_least_one_arg(as, error)) | |
1744 | return -EINVAL; | |
1745 | ||
1746 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1747 | &ca->cache_dev); | |
1748 | if (r) { | |
1749 | *error = "Error opening cache device"; | |
1750 | return r; | |
1751 | } | |
1752 | ca->cache_sectors = get_dev_size(ca->cache_dev); | |
1753 | ||
1754 | return 0; | |
1755 | } | |
1756 | ||
1757 | static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1758 | char **error) | |
1759 | { | |
1760 | int r; | |
1761 | ||
1762 | if (!at_least_one_arg(as, error)) | |
1763 | return -EINVAL; | |
1764 | ||
1765 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1766 | &ca->origin_dev); | |
1767 | if (r) { | |
1768 | *error = "Error opening origin device"; | |
1769 | return r; | |
1770 | } | |
1771 | ||
1772 | ca->origin_sectors = get_dev_size(ca->origin_dev); | |
1773 | if (ca->ti->len > ca->origin_sectors) { | |
1774 | *error = "Device size larger than cached device"; | |
1775 | return -EINVAL; | |
1776 | } | |
1777 | ||
1778 | return 0; | |
1779 | } | |
1780 | ||
1781 | static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, | |
1782 | char **error) | |
1783 | { | |
05473044 | 1784 | unsigned long block_size; |
c6b4fcba JT |
1785 | |
1786 | if (!at_least_one_arg(as, error)) | |
1787 | return -EINVAL; | |
1788 | ||
05473044 MS |
1789 | if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size || |
1790 | block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || | |
1791 | block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || | |
1792 | block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { | |
c6b4fcba JT |
1793 | *error = "Invalid data block size"; |
1794 | return -EINVAL; | |
1795 | } | |
1796 | ||
05473044 | 1797 | if (block_size > ca->cache_sectors) { |
c6b4fcba JT |
1798 | *error = "Data block size is larger than the cache device"; |
1799 | return -EINVAL; | |
1800 | } | |
1801 | ||
05473044 | 1802 | ca->block_size = block_size; |
c6b4fcba JT |
1803 | |
1804 | return 0; | |
1805 | } | |
1806 | ||
1807 | static void init_features(struct cache_features *cf) | |
1808 | { | |
1809 | cf->mode = CM_WRITE; | |
1810 | cf->write_through = false; | |
1811 | } | |
1812 | ||
1813 | static int parse_features(struct cache_args *ca, struct dm_arg_set *as, | |
1814 | char **error) | |
1815 | { | |
1816 | static struct dm_arg _args[] = { | |
1817 | {0, 1, "Invalid number of cache feature arguments"}, | |
1818 | }; | |
1819 | ||
1820 | int r; | |
1821 | unsigned argc; | |
1822 | const char *arg; | |
1823 | struct cache_features *cf = &ca->features; | |
1824 | ||
1825 | init_features(cf); | |
1826 | ||
1827 | r = dm_read_arg_group(_args, as, &argc, error); | |
1828 | if (r) | |
1829 | return -EINVAL; | |
1830 | ||
1831 | while (argc--) { | |
1832 | arg = dm_shift_arg(as); | |
1833 | ||
1834 | if (!strcasecmp(arg, "writeback")) | |
1835 | cf->write_through = false; | |
1836 | ||
1837 | else if (!strcasecmp(arg, "writethrough")) | |
1838 | cf->write_through = true; | |
1839 | ||
1840 | else { | |
1841 | *error = "Unrecognised cache feature requested"; | |
1842 | return -EINVAL; | |
1843 | } | |
1844 | } | |
1845 | ||
1846 | return 0; | |
1847 | } | |
1848 | ||
1849 | static int parse_policy(struct cache_args *ca, struct dm_arg_set *as, | |
1850 | char **error) | |
1851 | { | |
1852 | static struct dm_arg _args[] = { | |
1853 | {0, 1024, "Invalid number of policy arguments"}, | |
1854 | }; | |
1855 | ||
1856 | int r; | |
1857 | ||
1858 | if (!at_least_one_arg(as, error)) | |
1859 | return -EINVAL; | |
1860 | ||
1861 | ca->policy_name = dm_shift_arg(as); | |
1862 | ||
1863 | r = dm_read_arg_group(_args, as, &ca->policy_argc, error); | |
1864 | if (r) | |
1865 | return -EINVAL; | |
1866 | ||
1867 | ca->policy_argv = (const char **)as->argv; | |
1868 | dm_consume_args(as, ca->policy_argc); | |
1869 | ||
1870 | return 0; | |
1871 | } | |
1872 | ||
1873 | static int parse_cache_args(struct cache_args *ca, int argc, char **argv, | |
1874 | char **error) | |
1875 | { | |
1876 | int r; | |
1877 | struct dm_arg_set as; | |
1878 | ||
1879 | as.argc = argc; | |
1880 | as.argv = argv; | |
1881 | ||
1882 | r = parse_metadata_dev(ca, &as, error); | |
1883 | if (r) | |
1884 | return r; | |
1885 | ||
1886 | r = parse_cache_dev(ca, &as, error); | |
1887 | if (r) | |
1888 | return r; | |
1889 | ||
1890 | r = parse_origin_dev(ca, &as, error); | |
1891 | if (r) | |
1892 | return r; | |
1893 | ||
1894 | r = parse_block_size(ca, &as, error); | |
1895 | if (r) | |
1896 | return r; | |
1897 | ||
1898 | r = parse_features(ca, &as, error); | |
1899 | if (r) | |
1900 | return r; | |
1901 | ||
1902 | r = parse_policy(ca, &as, error); | |
1903 | if (r) | |
1904 | return r; | |
1905 | ||
1906 | return 0; | |
1907 | } | |
1908 | ||
1909 | /*----------------------------------------------------------------*/ | |
1910 | ||
1911 | static struct kmem_cache *migration_cache; | |
1912 | ||
2c73c471 AK |
1913 | #define NOT_CORE_OPTION 1 |
1914 | ||
2f14f4b5 | 1915 | static int process_config_option(struct cache *cache, const char *key, const char *value) |
2c73c471 AK |
1916 | { |
1917 | unsigned long tmp; | |
1918 | ||
2f14f4b5 JT |
1919 | if (!strcasecmp(key, "migration_threshold")) { |
1920 | if (kstrtoul(value, 10, &tmp)) | |
2c73c471 AK |
1921 | return -EINVAL; |
1922 | ||
1923 | cache->migration_threshold = tmp; | |
1924 | return 0; | |
1925 | } | |
1926 | ||
1927 | return NOT_CORE_OPTION; | |
1928 | } | |
1929 | ||
2f14f4b5 JT |
1930 | static int set_config_value(struct cache *cache, const char *key, const char *value) |
1931 | { | |
1932 | int r = process_config_option(cache, key, value); | |
1933 | ||
1934 | if (r == NOT_CORE_OPTION) | |
1935 | r = policy_set_config_value(cache->policy, key, value); | |
1936 | ||
1937 | if (r) | |
1938 | DMWARN("bad config value for %s: %s", key, value); | |
1939 | ||
1940 | return r; | |
1941 | } | |
1942 | ||
1943 | static int set_config_values(struct cache *cache, int argc, const char **argv) | |
c6b4fcba JT |
1944 | { |
1945 | int r = 0; | |
1946 | ||
1947 | if (argc & 1) { | |
1948 | DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs."); | |
1949 | return -EINVAL; | |
1950 | } | |
1951 | ||
1952 | while (argc) { | |
2f14f4b5 JT |
1953 | r = set_config_value(cache, argv[0], argv[1]); |
1954 | if (r) | |
1955 | break; | |
c6b4fcba JT |
1956 | |
1957 | argc -= 2; | |
1958 | argv += 2; | |
1959 | } | |
1960 | ||
1961 | return r; | |
1962 | } | |
1963 | ||
1964 | static int create_cache_policy(struct cache *cache, struct cache_args *ca, | |
1965 | char **error) | |
1966 | { | |
4cb3e1db MP |
1967 | struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name, |
1968 | cache->cache_size, | |
1969 | cache->origin_sectors, | |
1970 | cache->sectors_per_block); | |
1971 | if (IS_ERR(p)) { | |
c6b4fcba | 1972 | *error = "Error creating cache's policy"; |
4cb3e1db | 1973 | return PTR_ERR(p); |
c6b4fcba | 1974 | } |
4cb3e1db | 1975 | cache->policy = p; |
c6b4fcba | 1976 | |
2f14f4b5 | 1977 | return 0; |
c6b4fcba JT |
1978 | } |
1979 | ||
1980 | /* | |
1981 | * We want the discard block size to be a power of two, at least the size | |
1982 | * of the cache block size, and have no more than 2^14 discard blocks | |
1983 | * across the origin. | |
1984 | */ | |
1985 | #define MAX_DISCARD_BLOCKS (1 << 14) | |
1986 | ||
1987 | static bool too_many_discard_blocks(sector_t discard_block_size, | |
1988 | sector_t origin_size) | |
1989 | { | |
1990 | (void) sector_div(origin_size, discard_block_size); | |
1991 | ||
1992 | return origin_size > MAX_DISCARD_BLOCKS; | |
1993 | } | |
1994 | ||
1995 | static sector_t calculate_discard_block_size(sector_t cache_block_size, | |
1996 | sector_t origin_size) | |
1997 | { | |
1998 | sector_t discard_block_size; | |
1999 | ||
2000 | discard_block_size = roundup_pow_of_two(cache_block_size); | |
2001 | ||
2002 | if (origin_size) | |
2003 | while (too_many_discard_blocks(discard_block_size, origin_size)) | |
2004 | discard_block_size *= 2; | |
2005 | ||
2006 | return discard_block_size; | |
2007 | } | |
2008 | ||
f8350daf | 2009 | #define DEFAULT_MIGRATION_THRESHOLD 2048 |
c6b4fcba | 2010 | |
c6b4fcba JT |
2011 | static int cache_create(struct cache_args *ca, struct cache **result) |
2012 | { | |
2013 | int r = 0; | |
2014 | char **error = &ca->ti->error; | |
2015 | struct cache *cache; | |
2016 | struct dm_target *ti = ca->ti; | |
2017 | dm_block_t origin_blocks; | |
2018 | struct dm_cache_metadata *cmd; | |
2019 | bool may_format = ca->features.mode == CM_WRITE; | |
2020 | ||
2021 | cache = kzalloc(sizeof(*cache), GFP_KERNEL); | |
2022 | if (!cache) | |
2023 | return -ENOMEM; | |
2024 | ||
2025 | cache->ti = ca->ti; | |
2026 | ti->private = cache; | |
c6b4fcba JT |
2027 | ti->num_flush_bios = 2; |
2028 | ti->flush_supported = true; | |
2029 | ||
2030 | ti->num_discard_bios = 1; | |
2031 | ti->discards_supported = true; | |
2032 | ti->discard_zeroes_data_unsupported = true; | |
2033 | ||
8c5008fa | 2034 | cache->features = ca->features; |
19b0092e | 2035 | ti->per_bio_data_size = get_per_bio_data_size(cache); |
c6b4fcba | 2036 | |
c6b4fcba JT |
2037 | cache->callbacks.congested_fn = cache_is_congested; |
2038 | dm_table_add_target_callbacks(ti->table, &cache->callbacks); | |
2039 | ||
2040 | cache->metadata_dev = ca->metadata_dev; | |
2041 | cache->origin_dev = ca->origin_dev; | |
2042 | cache->cache_dev = ca->cache_dev; | |
2043 | ||
2044 | ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; | |
2045 | ||
2046 | /* FIXME: factor out this whole section */ | |
2047 | origin_blocks = cache->origin_sectors = ca->origin_sectors; | |
414dd67d | 2048 | origin_blocks = block_div(origin_blocks, ca->block_size); |
c6b4fcba JT |
2049 | cache->origin_blocks = to_oblock(origin_blocks); |
2050 | ||
2051 | cache->sectors_per_block = ca->block_size; | |
2052 | if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) { | |
2053 | r = -EINVAL; | |
2054 | goto bad; | |
2055 | } | |
2056 | ||
2057 | if (ca->block_size & (ca->block_size - 1)) { | |
2058 | dm_block_t cache_size = ca->cache_sectors; | |
2059 | ||
2060 | cache->sectors_per_block_shift = -1; | |
414dd67d | 2061 | cache_size = block_div(cache_size, ca->block_size); |
c6b4fcba JT |
2062 | cache->cache_size = to_cblock(cache_size); |
2063 | } else { | |
2064 | cache->sectors_per_block_shift = __ffs(ca->block_size); | |
2065 | cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift); | |
2066 | } | |
2067 | ||
2068 | r = create_cache_policy(cache, ca, error); | |
2069 | if (r) | |
2070 | goto bad; | |
2f14f4b5 | 2071 | |
c6b4fcba | 2072 | cache->policy_nr_args = ca->policy_argc; |
2f14f4b5 JT |
2073 | cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD; |
2074 | ||
2075 | r = set_config_values(cache, ca->policy_argc, ca->policy_argv); | |
2076 | if (r) { | |
2077 | *error = "Error setting cache policy's config values"; | |
2078 | goto bad; | |
2079 | } | |
c6b4fcba JT |
2080 | |
2081 | cmd = dm_cache_metadata_open(cache->metadata_dev->bdev, | |
2082 | ca->block_size, may_format, | |
2083 | dm_cache_policy_get_hint_size(cache->policy)); | |
2084 | if (IS_ERR(cmd)) { | |
2085 | *error = "Error creating metadata object"; | |
2086 | r = PTR_ERR(cmd); | |
2087 | goto bad; | |
2088 | } | |
2089 | cache->cmd = cmd; | |
2090 | ||
2091 | spin_lock_init(&cache->lock); | |
2092 | bio_list_init(&cache->deferred_bios); | |
2093 | bio_list_init(&cache->deferred_flush_bios); | |
e2e74d61 | 2094 | bio_list_init(&cache->deferred_writethrough_bios); |
c6b4fcba JT |
2095 | INIT_LIST_HEAD(&cache->quiesced_migrations); |
2096 | INIT_LIST_HEAD(&cache->completed_migrations); | |
2097 | INIT_LIST_HEAD(&cache->need_commit_migrations); | |
c6b4fcba JT |
2098 | atomic_set(&cache->nr_migrations, 0); |
2099 | init_waitqueue_head(&cache->migration_wait); | |
2100 | ||
66cb1910 | 2101 | init_waitqueue_head(&cache->quiescing_wait); |
238f8363 | 2102 | atomic_set(&cache->quiescing, 0); |
66cb1910 JT |
2103 | atomic_set(&cache->quiescing_ack, 0); |
2104 | ||
fa4d683a | 2105 | r = -ENOMEM; |
c6b4fcba JT |
2106 | cache->nr_dirty = 0; |
2107 | cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size)); | |
2108 | if (!cache->dirty_bitset) { | |
2109 | *error = "could not allocate dirty bitset"; | |
2110 | goto bad; | |
2111 | } | |
2112 | clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size)); | |
2113 | ||
2114 | cache->discard_block_size = | |
2115 | calculate_discard_block_size(cache->sectors_per_block, | |
2116 | cache->origin_sectors); | |
2117 | cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks); | |
2118 | cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks)); | |
2119 | if (!cache->discard_bitset) { | |
2120 | *error = "could not allocate discard bitset"; | |
2121 | goto bad; | |
2122 | } | |
2123 | clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); | |
2124 | ||
2125 | cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); | |
2126 | if (IS_ERR(cache->copier)) { | |
2127 | *error = "could not create kcopyd client"; | |
2128 | r = PTR_ERR(cache->copier); | |
2129 | goto bad; | |
2130 | } | |
2131 | ||
2132 | cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); | |
2133 | if (!cache->wq) { | |
2134 | *error = "could not create workqueue for metadata object"; | |
2135 | goto bad; | |
2136 | } | |
2137 | INIT_WORK(&cache->worker, do_worker); | |
2138 | INIT_DELAYED_WORK(&cache->waker, do_waker); | |
2139 | cache->last_commit_jiffies = jiffies; | |
2140 | ||
2141 | cache->prison = dm_bio_prison_create(PRISON_CELLS); | |
2142 | if (!cache->prison) { | |
2143 | *error = "could not create bio prison"; | |
2144 | goto bad; | |
2145 | } | |
2146 | ||
2147 | cache->all_io_ds = dm_deferred_set_create(); | |
2148 | if (!cache->all_io_ds) { | |
2149 | *error = "could not create all_io deferred set"; | |
2150 | goto bad; | |
2151 | } | |
2152 | ||
2153 | cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE, | |
2154 | migration_cache); | |
2155 | if (!cache->migration_pool) { | |
2156 | *error = "Error creating cache's migration mempool"; | |
2157 | goto bad; | |
2158 | } | |
2159 | ||
2160 | cache->next_migration = NULL; | |
2161 | ||
2162 | cache->need_tick_bio = true; | |
2163 | cache->sized = false; | |
c6b4fcba JT |
2164 | cache->commit_requested = false; |
2165 | cache->loaded_mappings = false; | |
2166 | cache->loaded_discards = false; | |
2167 | ||
2168 | load_stats(cache); | |
2169 | ||
2170 | atomic_set(&cache->stats.demotion, 0); | |
2171 | atomic_set(&cache->stats.promotion, 0); | |
2172 | atomic_set(&cache->stats.copies_avoided, 0); | |
2173 | atomic_set(&cache->stats.cache_cell_clash, 0); | |
2174 | atomic_set(&cache->stats.commit_count, 0); | |
2175 | atomic_set(&cache->stats.discard_count, 0); | |
2176 | ||
2177 | *result = cache; | |
2178 | return 0; | |
2179 | ||
2180 | bad: | |
2181 | destroy(cache); | |
2182 | return r; | |
2183 | } | |
2184 | ||
2185 | static int copy_ctr_args(struct cache *cache, int argc, const char **argv) | |
2186 | { | |
2187 | unsigned i; | |
2188 | const char **copy; | |
2189 | ||
2190 | copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL); | |
2191 | if (!copy) | |
2192 | return -ENOMEM; | |
2193 | for (i = 0; i < argc; i++) { | |
2194 | copy[i] = kstrdup(argv[i], GFP_KERNEL); | |
2195 | if (!copy[i]) { | |
2196 | while (i--) | |
2197 | kfree(copy[i]); | |
2198 | kfree(copy); | |
2199 | return -ENOMEM; | |
2200 | } | |
2201 | } | |
2202 | ||
2203 | cache->nr_ctr_args = argc; | |
2204 | cache->ctr_args = copy; | |
2205 | ||
2206 | return 0; | |
2207 | } | |
2208 | ||
2209 | static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
2210 | { | |
2211 | int r = -EINVAL; | |
2212 | struct cache_args *ca; | |
2213 | struct cache *cache = NULL; | |
2214 | ||
2215 | ca = kzalloc(sizeof(*ca), GFP_KERNEL); | |
2216 | if (!ca) { | |
2217 | ti->error = "Error allocating memory for cache"; | |
2218 | return -ENOMEM; | |
2219 | } | |
2220 | ca->ti = ti; | |
2221 | ||
2222 | r = parse_cache_args(ca, argc, argv, &ti->error); | |
2223 | if (r) | |
2224 | goto out; | |
2225 | ||
2226 | r = cache_create(ca, &cache); | |
617a0b89 HM |
2227 | if (r) |
2228 | goto out; | |
c6b4fcba JT |
2229 | |
2230 | r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3); | |
2231 | if (r) { | |
2232 | destroy(cache); | |
2233 | goto out; | |
2234 | } | |
2235 | ||
2236 | ti->private = cache; | |
2237 | ||
2238 | out: | |
2239 | destroy_cache_args(ca); | |
2240 | return r; | |
2241 | } | |
2242 | ||
c6b4fcba JT |
2243 | static int cache_map(struct dm_target *ti, struct bio *bio) |
2244 | { | |
2245 | struct cache *cache = ti->private; | |
2246 | ||
2247 | int r; | |
2248 | dm_oblock_t block = get_bio_block(cache, bio); | |
19b0092e | 2249 | size_t pb_data_size = get_per_bio_data_size(cache); |
c6b4fcba JT |
2250 | bool can_migrate = false; |
2251 | bool discarded_block; | |
2252 | struct dm_bio_prison_cell *cell; | |
2253 | struct policy_result lookup_result; | |
2254 | struct per_bio_data *pb; | |
2255 | ||
2256 | if (from_oblock(block) > from_oblock(cache->origin_blocks)) { | |
2257 | /* | |
2258 | * This can only occur if the io goes to a partial block at | |
2259 | * the end of the origin device. We don't cache these. | |
2260 | * Just remap to the origin and carry on. | |
2261 | */ | |
2262 | remap_to_origin_clear_discard(cache, bio, block); | |
2263 | return DM_MAPIO_REMAPPED; | |
2264 | } | |
2265 | ||
19b0092e | 2266 | pb = init_per_bio_data(bio, pb_data_size); |
c6b4fcba JT |
2267 | |
2268 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) { | |
2269 | defer_bio(cache, bio); | |
2270 | return DM_MAPIO_SUBMITTED; | |
2271 | } | |
2272 | ||
2273 | /* | |
2274 | * Check to see if that block is currently migrating. | |
2275 | */ | |
2276 | cell = alloc_prison_cell(cache); | |
2277 | if (!cell) { | |
2278 | defer_bio(cache, bio); | |
2279 | return DM_MAPIO_SUBMITTED; | |
2280 | } | |
2281 | ||
2282 | r = bio_detain(cache, block, bio, cell, | |
2283 | (cell_free_fn) free_prison_cell, | |
2284 | cache, &cell); | |
2285 | if (r) { | |
2286 | if (r < 0) | |
2287 | defer_bio(cache, bio); | |
2288 | ||
2289 | return DM_MAPIO_SUBMITTED; | |
2290 | } | |
2291 | ||
2292 | discarded_block = is_discarded_oblock(cache, block); | |
2293 | ||
2294 | r = policy_map(cache->policy, block, false, can_migrate, discarded_block, | |
2295 | bio, &lookup_result); | |
2296 | if (r == -EWOULDBLOCK) { | |
2297 | cell_defer(cache, cell, true); | |
2298 | return DM_MAPIO_SUBMITTED; | |
2299 | ||
2300 | } else if (r) { | |
2301 | DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r); | |
2302 | bio_io_error(bio); | |
2303 | return DM_MAPIO_SUBMITTED; | |
2304 | } | |
2305 | ||
2306 | switch (lookup_result.op) { | |
2307 | case POLICY_HIT: | |
2308 | inc_hit_counter(cache, bio); | |
2309 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
2310 | ||
e2e74d61 JT |
2311 | if (is_writethrough_io(cache, bio, lookup_result.cblock)) |
2312 | remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); | |
2313 | else | |
c6b4fcba | 2314 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); |
e2e74d61 JT |
2315 | |
2316 | cell_defer(cache, cell, false); | |
c6b4fcba JT |
2317 | break; |
2318 | ||
2319 | case POLICY_MISS: | |
2320 | inc_miss_counter(cache, bio); | |
2321 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
2322 | ||
2323 | if (pb->req_nr != 0) { | |
2324 | /* | |
2325 | * This is a duplicate writethrough io that is no | |
2326 | * longer needed because the block has been demoted. | |
2327 | */ | |
2328 | bio_endio(bio, 0); | |
2329 | cell_defer(cache, cell, false); | |
2330 | return DM_MAPIO_SUBMITTED; | |
2331 | } else { | |
2332 | remap_to_origin_clear_discard(cache, bio, block); | |
2333 | cell_defer(cache, cell, false); | |
2334 | } | |
2335 | break; | |
2336 | ||
2337 | default: | |
2338 | DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__, | |
2339 | (unsigned) lookup_result.op); | |
2340 | bio_io_error(bio); | |
2341 | return DM_MAPIO_SUBMITTED; | |
2342 | } | |
2343 | ||
2344 | return DM_MAPIO_REMAPPED; | |
2345 | } | |
2346 | ||
2347 | static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) | |
2348 | { | |
2349 | struct cache *cache = ti->private; | |
2350 | unsigned long flags; | |
19b0092e MS |
2351 | size_t pb_data_size = get_per_bio_data_size(cache); |
2352 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
2353 | |
2354 | if (pb->tick) { | |
2355 | policy_tick(cache->policy); | |
2356 | ||
2357 | spin_lock_irqsave(&cache->lock, flags); | |
2358 | cache->need_tick_bio = true; | |
2359 | spin_unlock_irqrestore(&cache->lock, flags); | |
2360 | } | |
2361 | ||
2362 | check_for_quiesced_migrations(cache, pb); | |
2363 | ||
2364 | return 0; | |
2365 | } | |
2366 | ||
2367 | static int write_dirty_bitset(struct cache *cache) | |
2368 | { | |
2369 | unsigned i, r; | |
2370 | ||
2371 | for (i = 0; i < from_cblock(cache->cache_size); i++) { | |
2372 | r = dm_cache_set_dirty(cache->cmd, to_cblock(i), | |
2373 | is_dirty(cache, to_cblock(i))); | |
2374 | if (r) | |
2375 | return r; | |
2376 | } | |
2377 | ||
2378 | return 0; | |
2379 | } | |
2380 | ||
2381 | static int write_discard_bitset(struct cache *cache) | |
2382 | { | |
2383 | unsigned i, r; | |
2384 | ||
2385 | r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size, | |
2386 | cache->discard_nr_blocks); | |
2387 | if (r) { | |
2388 | DMERR("could not resize on-disk discard bitset"); | |
2389 | return r; | |
2390 | } | |
2391 | ||
2392 | for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) { | |
2393 | r = dm_cache_set_discard(cache->cmd, to_dblock(i), | |
2394 | is_discarded(cache, to_dblock(i))); | |
2395 | if (r) | |
2396 | return r; | |
2397 | } | |
2398 | ||
2399 | return 0; | |
2400 | } | |
2401 | ||
2402 | static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, | |
2403 | uint32_t hint) | |
2404 | { | |
2405 | struct cache *cache = context; | |
2406 | return dm_cache_save_hint(cache->cmd, cblock, hint); | |
2407 | } | |
2408 | ||
2409 | static int write_hints(struct cache *cache) | |
2410 | { | |
2411 | int r; | |
2412 | ||
2413 | r = dm_cache_begin_hints(cache->cmd, cache->policy); | |
2414 | if (r) { | |
2415 | DMERR("dm_cache_begin_hints failed"); | |
2416 | return r; | |
2417 | } | |
2418 | ||
2419 | r = policy_walk_mappings(cache->policy, save_hint, cache); | |
2420 | if (r) | |
2421 | DMERR("policy_walk_mappings failed"); | |
2422 | ||
2423 | return r; | |
2424 | } | |
2425 | ||
2426 | /* | |
2427 | * returns true on success | |
2428 | */ | |
2429 | static bool sync_metadata(struct cache *cache) | |
2430 | { | |
2431 | int r1, r2, r3, r4; | |
2432 | ||
2433 | r1 = write_dirty_bitset(cache); | |
2434 | if (r1) | |
2435 | DMERR("could not write dirty bitset"); | |
2436 | ||
2437 | r2 = write_discard_bitset(cache); | |
2438 | if (r2) | |
2439 | DMERR("could not write discard bitset"); | |
2440 | ||
2441 | save_stats(cache); | |
2442 | ||
2443 | r3 = write_hints(cache); | |
2444 | if (r3) | |
2445 | DMERR("could not write hints"); | |
2446 | ||
2447 | /* | |
2448 | * If writing the above metadata failed, we still commit, but don't | |
2449 | * set the clean shutdown flag. This will effectively force every | |
2450 | * dirty bit to be set on reload. | |
2451 | */ | |
2452 | r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3); | |
2453 | if (r4) | |
2454 | DMERR("could not write cache metadata. Data loss may occur."); | |
2455 | ||
2456 | return !r1 && !r2 && !r3 && !r4; | |
2457 | } | |
2458 | ||
2459 | static void cache_postsuspend(struct dm_target *ti) | |
2460 | { | |
2461 | struct cache *cache = ti->private; | |
2462 | ||
2463 | start_quiescing(cache); | |
2464 | wait_for_migrations(cache); | |
2465 | stop_worker(cache); | |
2466 | requeue_deferred_io(cache); | |
2467 | stop_quiescing(cache); | |
2468 | ||
2469 | (void) sync_metadata(cache); | |
2470 | } | |
2471 | ||
2472 | static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, | |
2473 | bool dirty, uint32_t hint, bool hint_valid) | |
2474 | { | |
2475 | int r; | |
2476 | struct cache *cache = context; | |
2477 | ||
2478 | r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid); | |
2479 | if (r) | |
2480 | return r; | |
2481 | ||
2482 | if (dirty) | |
2483 | set_dirty(cache, oblock, cblock); | |
2484 | else | |
2485 | clear_dirty(cache, oblock, cblock); | |
2486 | ||
2487 | return 0; | |
2488 | } | |
2489 | ||
2490 | static int load_discard(void *context, sector_t discard_block_size, | |
2491 | dm_dblock_t dblock, bool discard) | |
2492 | { | |
2493 | struct cache *cache = context; | |
2494 | ||
2495 | /* FIXME: handle mis-matched block size */ | |
2496 | ||
2497 | if (discard) | |
2498 | set_discard(cache, dblock); | |
2499 | else | |
2500 | clear_discard(cache, dblock); | |
2501 | ||
2502 | return 0; | |
2503 | } | |
2504 | ||
f494a9c6 JT |
2505 | static dm_cblock_t get_cache_dev_size(struct cache *cache) |
2506 | { | |
2507 | sector_t size = get_dev_size(cache->cache_dev); | |
2508 | (void) sector_div(size, cache->sectors_per_block); | |
2509 | return to_cblock(size); | |
2510 | } | |
2511 | ||
2512 | static bool can_resize(struct cache *cache, dm_cblock_t new_size) | |
2513 | { | |
2514 | if (from_cblock(new_size) > from_cblock(cache->cache_size)) | |
2515 | return true; | |
2516 | ||
2517 | /* | |
2518 | * We can't drop a dirty block when shrinking the cache. | |
2519 | */ | |
2520 | while (from_cblock(new_size) < from_cblock(cache->cache_size)) { | |
2521 | new_size = to_cblock(from_cblock(new_size) + 1); | |
2522 | if (is_dirty(cache, new_size)) { | |
2523 | DMERR("unable to shrink cache; cache block %llu is dirty", | |
2524 | (unsigned long long) from_cblock(new_size)); | |
2525 | return false; | |
2526 | } | |
2527 | } | |
2528 | ||
2529 | return true; | |
2530 | } | |
2531 | ||
2532 | static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size) | |
2533 | { | |
2534 | int r; | |
2535 | ||
2536 | r = dm_cache_resize(cache->cmd, cache->cache_size); | |
2537 | if (r) { | |
2538 | DMERR("could not resize cache metadata"); | |
2539 | return r; | |
2540 | } | |
2541 | ||
2542 | cache->cache_size = new_size; | |
2543 | ||
2544 | return 0; | |
2545 | } | |
2546 | ||
c6b4fcba JT |
2547 | static int cache_preresume(struct dm_target *ti) |
2548 | { | |
2549 | int r = 0; | |
2550 | struct cache *cache = ti->private; | |
f494a9c6 | 2551 | dm_cblock_t csize = get_cache_dev_size(cache); |
c6b4fcba JT |
2552 | |
2553 | /* | |
2554 | * Check to see if the cache has resized. | |
2555 | */ | |
f494a9c6 JT |
2556 | if (!cache->sized) { |
2557 | r = resize_cache_dev(cache, csize); | |
2558 | if (r) | |
c6b4fcba | 2559 | return r; |
c6b4fcba JT |
2560 | |
2561 | cache->sized = true; | |
f494a9c6 JT |
2562 | |
2563 | } else if (csize != cache->cache_size) { | |
2564 | if (!can_resize(cache, csize)) | |
2565 | return -EINVAL; | |
2566 | ||
2567 | r = resize_cache_dev(cache, csize); | |
2568 | if (r) | |
2569 | return r; | |
c6b4fcba JT |
2570 | } |
2571 | ||
2572 | if (!cache->loaded_mappings) { | |
ea2dd8c1 | 2573 | r = dm_cache_load_mappings(cache->cmd, cache->policy, |
c6b4fcba JT |
2574 | load_mapping, cache); |
2575 | if (r) { | |
2576 | DMERR("could not load cache mappings"); | |
2577 | return r; | |
2578 | } | |
2579 | ||
2580 | cache->loaded_mappings = true; | |
2581 | } | |
2582 | ||
2583 | if (!cache->loaded_discards) { | |
2584 | r = dm_cache_load_discards(cache->cmd, load_discard, cache); | |
2585 | if (r) { | |
2586 | DMERR("could not load origin discards"); | |
2587 | return r; | |
2588 | } | |
2589 | ||
2590 | cache->loaded_discards = true; | |
2591 | } | |
2592 | ||
2593 | return r; | |
2594 | } | |
2595 | ||
2596 | static void cache_resume(struct dm_target *ti) | |
2597 | { | |
2598 | struct cache *cache = ti->private; | |
2599 | ||
2600 | cache->need_tick_bio = true; | |
2601 | do_waker(&cache->waker.work); | |
2602 | } | |
2603 | ||
2604 | /* | |
2605 | * Status format: | |
2606 | * | |
2607 | * <#used metadata blocks>/<#total metadata blocks> | |
2608 | * <#read hits> <#read misses> <#write hits> <#write misses> | |
2609 | * <#demotions> <#promotions> <#blocks in cache> <#dirty> | |
2610 | * <#features> <features>* | |
2611 | * <#core args> <core args> | |
2612 | * <#policy args> <policy args>* | |
2613 | */ | |
2614 | static void cache_status(struct dm_target *ti, status_type_t type, | |
2615 | unsigned status_flags, char *result, unsigned maxlen) | |
2616 | { | |
2617 | int r = 0; | |
2618 | unsigned i; | |
2619 | ssize_t sz = 0; | |
2620 | dm_block_t nr_free_blocks_metadata = 0; | |
2621 | dm_block_t nr_blocks_metadata = 0; | |
2622 | char buf[BDEVNAME_SIZE]; | |
2623 | struct cache *cache = ti->private; | |
2624 | dm_cblock_t residency; | |
2625 | ||
2626 | switch (type) { | |
2627 | case STATUSTYPE_INFO: | |
2628 | /* Commit to ensure statistics aren't out-of-date */ | |
2629 | if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) { | |
2630 | r = dm_cache_commit(cache->cmd, false); | |
2631 | if (r) | |
2632 | DMERR("could not commit metadata for accurate status"); | |
2633 | } | |
2634 | ||
2635 | r = dm_cache_get_free_metadata_block_count(cache->cmd, | |
2636 | &nr_free_blocks_metadata); | |
2637 | if (r) { | |
2638 | DMERR("could not get metadata free block count"); | |
2639 | goto err; | |
2640 | } | |
2641 | ||
2642 | r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata); | |
2643 | if (r) { | |
2644 | DMERR("could not get metadata device size"); | |
2645 | goto err; | |
2646 | } | |
2647 | ||
2648 | residency = policy_residency(cache->policy); | |
2649 | ||
2650 | DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ", | |
2651 | (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), | |
2652 | (unsigned long long)nr_blocks_metadata, | |
2653 | (unsigned) atomic_read(&cache->stats.read_hit), | |
2654 | (unsigned) atomic_read(&cache->stats.read_miss), | |
2655 | (unsigned) atomic_read(&cache->stats.write_hit), | |
2656 | (unsigned) atomic_read(&cache->stats.write_miss), | |
2657 | (unsigned) atomic_read(&cache->stats.demotion), | |
2658 | (unsigned) atomic_read(&cache->stats.promotion), | |
2659 | (unsigned long long) from_cblock(residency), | |
2660 | cache->nr_dirty); | |
2661 | ||
2662 | if (cache->features.write_through) | |
2663 | DMEMIT("1 writethrough "); | |
2664 | else | |
2665 | DMEMIT("0 "); | |
2666 | ||
2667 | DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold); | |
2668 | if (sz < maxlen) { | |
2669 | r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz); | |
2670 | if (r) | |
2671 | DMERR("policy_emit_config_values returned %d", r); | |
2672 | } | |
2673 | ||
2674 | break; | |
2675 | ||
2676 | case STATUSTYPE_TABLE: | |
2677 | format_dev_t(buf, cache->metadata_dev->bdev->bd_dev); | |
2678 | DMEMIT("%s ", buf); | |
2679 | format_dev_t(buf, cache->cache_dev->bdev->bd_dev); | |
2680 | DMEMIT("%s ", buf); | |
2681 | format_dev_t(buf, cache->origin_dev->bdev->bd_dev); | |
2682 | DMEMIT("%s", buf); | |
2683 | ||
2684 | for (i = 0; i < cache->nr_ctr_args - 1; i++) | |
2685 | DMEMIT(" %s", cache->ctr_args[i]); | |
2686 | if (cache->nr_ctr_args) | |
2687 | DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]); | |
2688 | } | |
2689 | ||
2690 | return; | |
2691 | ||
2692 | err: | |
2693 | DMEMIT("Error"); | |
2694 | } | |
2695 | ||
c6b4fcba JT |
2696 | /* |
2697 | * Supports <key> <value>. | |
2698 | * | |
2699 | * The key migration_threshold is supported by the cache target core. | |
2700 | */ | |
2701 | static int cache_message(struct dm_target *ti, unsigned argc, char **argv) | |
2702 | { | |
c6b4fcba JT |
2703 | struct cache *cache = ti->private; |
2704 | ||
2705 | if (argc != 2) | |
2706 | return -EINVAL; | |
2707 | ||
2f14f4b5 | 2708 | return set_config_value(cache, argv[0], argv[1]); |
c6b4fcba JT |
2709 | } |
2710 | ||
2711 | static int cache_iterate_devices(struct dm_target *ti, | |
2712 | iterate_devices_callout_fn fn, void *data) | |
2713 | { | |
2714 | int r = 0; | |
2715 | struct cache *cache = ti->private; | |
2716 | ||
2717 | r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data); | |
2718 | if (!r) | |
2719 | r = fn(ti, cache->origin_dev, 0, ti->len, data); | |
2720 | ||
2721 | return r; | |
2722 | } | |
2723 | ||
2724 | /* | |
2725 | * We assume I/O is going to the origin (which is the volume | |
2726 | * more likely to have restrictions e.g. by being striped). | |
2727 | * (Looking up the exact location of the data would be expensive | |
2728 | * and could always be out of date by the time the bio is submitted.) | |
2729 | */ | |
2730 | static int cache_bvec_merge(struct dm_target *ti, | |
2731 | struct bvec_merge_data *bvm, | |
2732 | struct bio_vec *biovec, int max_size) | |
2733 | { | |
2734 | struct cache *cache = ti->private; | |
2735 | struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev); | |
2736 | ||
2737 | if (!q->merge_bvec_fn) | |
2738 | return max_size; | |
2739 | ||
2740 | bvm->bi_bdev = cache->origin_dev->bdev; | |
2741 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
2742 | } | |
2743 | ||
2744 | static void set_discard_limits(struct cache *cache, struct queue_limits *limits) | |
2745 | { | |
2746 | /* | |
2747 | * FIXME: these limits may be incompatible with the cache device | |
2748 | */ | |
2749 | limits->max_discard_sectors = cache->discard_block_size * 1024; | |
2750 | limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT; | |
2751 | } | |
2752 | ||
2753 | static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
2754 | { | |
2755 | struct cache *cache = ti->private; | |
f6109372 | 2756 | uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; |
c6b4fcba | 2757 | |
f6109372 MS |
2758 | /* |
2759 | * If the system-determined stacked limits are compatible with the | |
2760 | * cache's blocksize (io_opt is a factor) do not override them. | |
2761 | */ | |
2762 | if (io_opt_sectors < cache->sectors_per_block || | |
2763 | do_div(io_opt_sectors, cache->sectors_per_block)) { | |
2764 | blk_limits_io_min(limits, 0); | |
2765 | blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT); | |
2766 | } | |
c6b4fcba JT |
2767 | set_discard_limits(cache, limits); |
2768 | } | |
2769 | ||
2770 | /*----------------------------------------------------------------*/ | |
2771 | ||
2772 | static struct target_type cache_target = { | |
2773 | .name = "cache", | |
2f14f4b5 | 2774 | .version = {1, 1, 1}, |
c6b4fcba JT |
2775 | .module = THIS_MODULE, |
2776 | .ctr = cache_ctr, | |
2777 | .dtr = cache_dtr, | |
2778 | .map = cache_map, | |
2779 | .end_io = cache_end_io, | |
2780 | .postsuspend = cache_postsuspend, | |
2781 | .preresume = cache_preresume, | |
2782 | .resume = cache_resume, | |
2783 | .status = cache_status, | |
2784 | .message = cache_message, | |
2785 | .iterate_devices = cache_iterate_devices, | |
2786 | .merge = cache_bvec_merge, | |
2787 | .io_hints = cache_io_hints, | |
2788 | }; | |
2789 | ||
2790 | static int __init dm_cache_init(void) | |
2791 | { | |
2792 | int r; | |
2793 | ||
2794 | r = dm_register_target(&cache_target); | |
2795 | if (r) { | |
2796 | DMERR("cache target registration failed: %d", r); | |
2797 | return r; | |
2798 | } | |
2799 | ||
2800 | migration_cache = KMEM_CACHE(dm_cache_migration, 0); | |
2801 | if (!migration_cache) { | |
2802 | dm_unregister_target(&cache_target); | |
2803 | return -ENOMEM; | |
2804 | } | |
2805 | ||
2806 | return 0; | |
2807 | } | |
2808 | ||
2809 | static void __exit dm_cache_exit(void) | |
2810 | { | |
2811 | dm_unregister_target(&cache_target); | |
2812 | kmem_cache_destroy(migration_cache); | |
2813 | } | |
2814 | ||
2815 | module_init(dm_cache_init); | |
2816 | module_exit(dm_cache_exit); | |
2817 | ||
2818 | MODULE_DESCRIPTION(DM_NAME " cache target"); | |
2819 | MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); | |
2820 | MODULE_LICENSE("GPL"); |