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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-v2.h" | |
9 | #include "dm-bio-record.h" | |
10 | #include "dm-cache-metadata.h" | |
11 | ||
12 | #include <linux/dm-io.h> | |
13 | #include <linux/dm-kcopyd.h> | |
14 | #include <linux/jiffies.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/mempool.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/rwsem.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/vmalloc.h> | |
21 | ||
22 | #define DM_MSG_PREFIX "cache" | |
23 | ||
24 | DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle, | |
25 | "A percentage of time allocated for copying to and/or from cache"); | |
26 | ||
27 | /*----------------------------------------------------------------*/ | |
28 | ||
29 | /* | |
30 | * Glossary: | |
31 | * | |
32 | * oblock: index of an origin block | |
33 | * cblock: index of a cache block | |
34 | * promotion: movement of a block from origin to cache | |
35 | * demotion: movement of a block from cache to origin | |
36 | * migration: movement of a block between the origin and cache device, | |
37 | * either direction | |
38 | */ | |
39 | ||
40 | /*----------------------------------------------------------------*/ | |
41 | ||
42 | struct io_tracker { | |
43 | spinlock_t lock; | |
44 | ||
45 | /* | |
46 | * Sectors of in-flight IO. | |
47 | */ | |
48 | sector_t in_flight; | |
49 | ||
50 | /* | |
51 | * The time, in jiffies, when this device became idle (if it is | |
52 | * indeed idle). | |
53 | */ | |
54 | unsigned long idle_time; | |
55 | unsigned long last_update_time; | |
56 | }; | |
57 | ||
58 | static void iot_init(struct io_tracker *iot) | |
59 | { | |
60 | spin_lock_init(&iot->lock); | |
61 | iot->in_flight = 0ul; | |
62 | iot->idle_time = 0ul; | |
63 | iot->last_update_time = jiffies; | |
64 | } | |
65 | ||
66 | static bool __iot_idle_for(struct io_tracker *iot, unsigned long jifs) | |
67 | { | |
68 | if (iot->in_flight) | |
69 | return false; | |
70 | ||
71 | return time_after(jiffies, iot->idle_time + jifs); | |
72 | } | |
73 | ||
74 | static bool iot_idle_for(struct io_tracker *iot, unsigned long jifs) | |
75 | { | |
76 | bool r; | |
77 | unsigned long flags; | |
78 | ||
79 | spin_lock_irqsave(&iot->lock, flags); | |
80 | r = __iot_idle_for(iot, jifs); | |
81 | spin_unlock_irqrestore(&iot->lock, flags); | |
82 | ||
83 | return r; | |
84 | } | |
85 | ||
86 | static void iot_io_begin(struct io_tracker *iot, sector_t len) | |
87 | { | |
88 | unsigned long flags; | |
89 | ||
90 | spin_lock_irqsave(&iot->lock, flags); | |
91 | iot->in_flight += len; | |
92 | spin_unlock_irqrestore(&iot->lock, flags); | |
93 | } | |
94 | ||
95 | static void __iot_io_end(struct io_tracker *iot, sector_t len) | |
96 | { | |
97 | if (!len) | |
98 | return; | |
99 | ||
100 | iot->in_flight -= len; | |
101 | if (!iot->in_flight) | |
102 | iot->idle_time = jiffies; | |
103 | } | |
104 | ||
105 | static void iot_io_end(struct io_tracker *iot, sector_t len) | |
106 | { | |
107 | unsigned long flags; | |
108 | ||
109 | spin_lock_irqsave(&iot->lock, flags); | |
110 | __iot_io_end(iot, len); | |
111 | spin_unlock_irqrestore(&iot->lock, flags); | |
112 | } | |
113 | ||
114 | /*----------------------------------------------------------------*/ | |
115 | ||
116 | /* | |
117 | * Represents a chunk of future work. 'input' allows continuations to pass | |
118 | * values between themselves, typically error values. | |
119 | */ | |
120 | struct continuation { | |
121 | struct work_struct ws; | |
122 | blk_status_t input; | |
123 | }; | |
124 | ||
125 | static inline void init_continuation(struct continuation *k, | |
126 | void (*fn)(struct work_struct *)) | |
127 | { | |
128 | INIT_WORK(&k->ws, fn); | |
129 | k->input = 0; | |
130 | } | |
131 | ||
132 | static inline void queue_continuation(struct workqueue_struct *wq, | |
133 | struct continuation *k) | |
134 | { | |
135 | queue_work(wq, &k->ws); | |
136 | } | |
137 | ||
138 | /*----------------------------------------------------------------*/ | |
139 | ||
140 | /* | |
141 | * The batcher collects together pieces of work that need a particular | |
142 | * operation to occur before they can proceed (typically a commit). | |
143 | */ | |
144 | struct batcher { | |
145 | /* | |
146 | * The operation that everyone is waiting for. | |
147 | */ | |
148 | blk_status_t (*commit_op)(void *context); | |
149 | void *commit_context; | |
150 | ||
151 | /* | |
152 | * This is how bios should be issued once the commit op is complete | |
153 | * (accounted_request). | |
154 | */ | |
155 | void (*issue_op)(struct bio *bio, void *context); | |
156 | void *issue_context; | |
157 | ||
158 | /* | |
159 | * Queued work gets put on here after commit. | |
160 | */ | |
161 | struct workqueue_struct *wq; | |
162 | ||
163 | spinlock_t lock; | |
164 | struct list_head work_items; | |
165 | struct bio_list bios; | |
166 | struct work_struct commit_work; | |
167 | ||
168 | bool commit_scheduled; | |
169 | }; | |
170 | ||
171 | static void __commit(struct work_struct *_ws) | |
172 | { | |
173 | struct batcher *b = container_of(_ws, struct batcher, commit_work); | |
174 | blk_status_t r; | |
175 | unsigned long flags; | |
176 | struct list_head work_items; | |
177 | struct work_struct *ws, *tmp; | |
178 | struct continuation *k; | |
179 | struct bio *bio; | |
180 | struct bio_list bios; | |
181 | ||
182 | INIT_LIST_HEAD(&work_items); | |
183 | bio_list_init(&bios); | |
184 | ||
185 | /* | |
186 | * We have to grab these before the commit_op to avoid a race | |
187 | * condition. | |
188 | */ | |
189 | spin_lock_irqsave(&b->lock, flags); | |
190 | list_splice_init(&b->work_items, &work_items); | |
191 | bio_list_merge(&bios, &b->bios); | |
192 | bio_list_init(&b->bios); | |
193 | b->commit_scheduled = false; | |
194 | spin_unlock_irqrestore(&b->lock, flags); | |
195 | ||
196 | r = b->commit_op(b->commit_context); | |
197 | ||
198 | list_for_each_entry_safe(ws, tmp, &work_items, entry) { | |
199 | k = container_of(ws, struct continuation, ws); | |
200 | k->input = r; | |
201 | INIT_LIST_HEAD(&ws->entry); /* to avoid a WARN_ON */ | |
202 | queue_work(b->wq, ws); | |
203 | } | |
204 | ||
205 | while ((bio = bio_list_pop(&bios))) { | |
206 | if (r) { | |
207 | bio->bi_status = r; | |
208 | bio_endio(bio); | |
209 | } else | |
210 | b->issue_op(bio, b->issue_context); | |
211 | } | |
212 | } | |
213 | ||
214 | static void batcher_init(struct batcher *b, | |
215 | blk_status_t (*commit_op)(void *), | |
216 | void *commit_context, | |
217 | void (*issue_op)(struct bio *bio, void *), | |
218 | void *issue_context, | |
219 | struct workqueue_struct *wq) | |
220 | { | |
221 | b->commit_op = commit_op; | |
222 | b->commit_context = commit_context; | |
223 | b->issue_op = issue_op; | |
224 | b->issue_context = issue_context; | |
225 | b->wq = wq; | |
226 | ||
227 | spin_lock_init(&b->lock); | |
228 | INIT_LIST_HEAD(&b->work_items); | |
229 | bio_list_init(&b->bios); | |
230 | INIT_WORK(&b->commit_work, __commit); | |
231 | b->commit_scheduled = false; | |
232 | } | |
233 | ||
234 | static void async_commit(struct batcher *b) | |
235 | { | |
236 | queue_work(b->wq, &b->commit_work); | |
237 | } | |
238 | ||
239 | static void continue_after_commit(struct batcher *b, struct continuation *k) | |
240 | { | |
241 | unsigned long flags; | |
242 | bool commit_scheduled; | |
243 | ||
244 | spin_lock_irqsave(&b->lock, flags); | |
245 | commit_scheduled = b->commit_scheduled; | |
246 | list_add_tail(&k->ws.entry, &b->work_items); | |
247 | spin_unlock_irqrestore(&b->lock, flags); | |
248 | ||
249 | if (commit_scheduled) | |
250 | async_commit(b); | |
251 | } | |
252 | ||
253 | /* | |
254 | * Bios are errored if commit failed. | |
255 | */ | |
256 | static void issue_after_commit(struct batcher *b, struct bio *bio) | |
257 | { | |
258 | unsigned long flags; | |
259 | bool commit_scheduled; | |
260 | ||
261 | spin_lock_irqsave(&b->lock, flags); | |
262 | commit_scheduled = b->commit_scheduled; | |
263 | bio_list_add(&b->bios, bio); | |
264 | spin_unlock_irqrestore(&b->lock, flags); | |
265 | ||
266 | if (commit_scheduled) | |
267 | async_commit(b); | |
268 | } | |
269 | ||
270 | /* | |
271 | * Call this if some urgent work is waiting for the commit to complete. | |
272 | */ | |
273 | static void schedule_commit(struct batcher *b) | |
274 | { | |
275 | bool immediate; | |
276 | unsigned long flags; | |
277 | ||
278 | spin_lock_irqsave(&b->lock, flags); | |
279 | immediate = !list_empty(&b->work_items) || !bio_list_empty(&b->bios); | |
280 | b->commit_scheduled = true; | |
281 | spin_unlock_irqrestore(&b->lock, flags); | |
282 | ||
283 | if (immediate) | |
284 | async_commit(b); | |
285 | } | |
286 | ||
287 | /* | |
288 | * There are a couple of places where we let a bio run, but want to do some | |
289 | * work before calling its endio function. We do this by temporarily | |
290 | * changing the endio fn. | |
291 | */ | |
292 | struct dm_hook_info { | |
293 | bio_end_io_t *bi_end_io; | |
294 | }; | |
295 | ||
296 | static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio, | |
297 | bio_end_io_t *bi_end_io, void *bi_private) | |
298 | { | |
299 | h->bi_end_io = bio->bi_end_io; | |
300 | ||
301 | bio->bi_end_io = bi_end_io; | |
302 | bio->bi_private = bi_private; | |
303 | } | |
304 | ||
305 | static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio) | |
306 | { | |
307 | bio->bi_end_io = h->bi_end_io; | |
308 | } | |
309 | ||
310 | /*----------------------------------------------------------------*/ | |
311 | ||
312 | #define MIGRATION_POOL_SIZE 128 | |
313 | #define COMMIT_PERIOD HZ | |
314 | #define MIGRATION_COUNT_WINDOW 10 | |
315 | ||
316 | /* | |
317 | * The block size of the device holding cache data must be | |
318 | * between 32KB and 1GB. | |
319 | */ | |
320 | #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) | |
321 | #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) | |
322 | ||
323 | enum cache_metadata_mode { | |
324 | CM_WRITE, /* metadata may be changed */ | |
325 | CM_READ_ONLY, /* metadata may not be changed */ | |
326 | CM_FAIL | |
327 | }; | |
328 | ||
329 | enum cache_io_mode { | |
330 | /* | |
331 | * Data is written to cached blocks only. These blocks are marked | |
332 | * dirty. If you lose the cache device you will lose data. | |
333 | * Potential performance increase for both reads and writes. | |
334 | */ | |
335 | CM_IO_WRITEBACK, | |
336 | ||
337 | /* | |
338 | * Data is written to both cache and origin. Blocks are never | |
339 | * dirty. Potential performance benfit for reads only. | |
340 | */ | |
341 | CM_IO_WRITETHROUGH, | |
342 | ||
343 | /* | |
344 | * A degraded mode useful for various cache coherency situations | |
345 | * (eg, rolling back snapshots). Reads and writes always go to the | |
346 | * origin. If a write goes to a cached oblock, then the cache | |
347 | * block is invalidated. | |
348 | */ | |
349 | CM_IO_PASSTHROUGH | |
350 | }; | |
351 | ||
352 | struct cache_features { | |
353 | enum cache_metadata_mode mode; | |
354 | enum cache_io_mode io_mode; | |
355 | unsigned metadata_version; | |
356 | }; | |
357 | ||
358 | struct cache_stats { | |
359 | atomic_t read_hit; | |
360 | atomic_t read_miss; | |
361 | atomic_t write_hit; | |
362 | atomic_t write_miss; | |
363 | atomic_t demotion; | |
364 | atomic_t promotion; | |
365 | atomic_t writeback; | |
366 | atomic_t copies_avoided; | |
367 | atomic_t cache_cell_clash; | |
368 | atomic_t commit_count; | |
369 | atomic_t discard_count; | |
370 | }; | |
371 | ||
372 | struct cache { | |
373 | struct dm_target *ti; | |
374 | struct dm_target_callbacks callbacks; | |
375 | ||
376 | struct dm_cache_metadata *cmd; | |
377 | ||
378 | /* | |
379 | * Metadata is written to this device. | |
380 | */ | |
381 | struct dm_dev *metadata_dev; | |
382 | ||
383 | /* | |
384 | * The slower of the two data devices. Typically a spindle. | |
385 | */ | |
386 | struct dm_dev *origin_dev; | |
387 | ||
388 | /* | |
389 | * The faster of the two data devices. Typically an SSD. | |
390 | */ | |
391 | struct dm_dev *cache_dev; | |
392 | ||
393 | /* | |
394 | * Size of the origin device in _complete_ blocks and native sectors. | |
395 | */ | |
396 | dm_oblock_t origin_blocks; | |
397 | sector_t origin_sectors; | |
398 | ||
399 | /* | |
400 | * Size of the cache device in blocks. | |
401 | */ | |
402 | dm_cblock_t cache_size; | |
403 | ||
404 | /* | |
405 | * Fields for converting from sectors to blocks. | |
406 | */ | |
407 | sector_t sectors_per_block; | |
408 | int sectors_per_block_shift; | |
409 | ||
410 | spinlock_t lock; | |
411 | struct list_head deferred_cells; | |
412 | struct bio_list deferred_bios; | |
413 | struct bio_list deferred_writethrough_bios; | |
414 | sector_t migration_threshold; | |
415 | wait_queue_head_t migration_wait; | |
416 | atomic_t nr_allocated_migrations; | |
417 | ||
418 | /* | |
419 | * The number of in flight migrations that are performing | |
420 | * background io. eg, promotion, writeback. | |
421 | */ | |
422 | atomic_t nr_io_migrations; | |
423 | ||
424 | struct rw_semaphore quiesce_lock; | |
425 | ||
426 | /* | |
427 | * cache_size entries, dirty if set | |
428 | */ | |
429 | atomic_t nr_dirty; | |
430 | unsigned long *dirty_bitset; | |
431 | ||
432 | /* | |
433 | * origin_blocks entries, discarded if set. | |
434 | */ | |
435 | dm_dblock_t discard_nr_blocks; | |
436 | unsigned long *discard_bitset; | |
437 | uint32_t discard_block_size; /* a power of 2 times sectors per block */ | |
438 | ||
439 | /* | |
440 | * Rather than reconstructing the table line for the status we just | |
441 | * save it and regurgitate. | |
442 | */ | |
443 | unsigned nr_ctr_args; | |
444 | const char **ctr_args; | |
445 | ||
446 | struct dm_kcopyd_client *copier; | |
447 | struct workqueue_struct *wq; | |
448 | struct work_struct deferred_bio_worker; | |
449 | struct work_struct deferred_writethrough_worker; | |
450 | struct work_struct migration_worker; | |
451 | struct delayed_work waker; | |
452 | struct dm_bio_prison_v2 *prison; | |
453 | ||
454 | mempool_t *migration_pool; | |
455 | ||
456 | struct dm_cache_policy *policy; | |
457 | unsigned policy_nr_args; | |
458 | ||
459 | bool need_tick_bio:1; | |
460 | bool sized:1; | |
461 | bool invalidate:1; | |
462 | bool commit_requested:1; | |
463 | bool loaded_mappings:1; | |
464 | bool loaded_discards:1; | |
465 | ||
466 | /* | |
467 | * Cache features such as write-through. | |
468 | */ | |
469 | struct cache_features features; | |
470 | ||
471 | struct cache_stats stats; | |
472 | ||
473 | /* | |
474 | * Invalidation fields. | |
475 | */ | |
476 | spinlock_t invalidation_lock; | |
477 | struct list_head invalidation_requests; | |
478 | ||
479 | struct io_tracker tracker; | |
480 | ||
481 | struct work_struct commit_ws; | |
482 | struct batcher committer; | |
483 | ||
484 | struct rw_semaphore background_work_lock; | |
485 | }; | |
486 | ||
487 | struct per_bio_data { | |
488 | bool tick:1; | |
489 | unsigned req_nr:2; | |
490 | struct dm_bio_prison_cell_v2 *cell; | |
491 | struct dm_hook_info hook_info; | |
492 | sector_t len; | |
493 | ||
494 | /* | |
495 | * writethrough fields. These MUST remain at the end of this | |
496 | * structure and the 'cache' member must be the first as it | |
497 | * is used to determine the offset of the writethrough fields. | |
498 | */ | |
499 | struct cache *cache; | |
500 | dm_cblock_t cblock; | |
501 | struct dm_bio_details bio_details; | |
502 | }; | |
503 | ||
504 | struct dm_cache_migration { | |
505 | struct continuation k; | |
506 | struct cache *cache; | |
507 | ||
508 | struct policy_work *op; | |
509 | struct bio *overwrite_bio; | |
510 | struct dm_bio_prison_cell_v2 *cell; | |
511 | ||
512 | dm_cblock_t invalidate_cblock; | |
513 | dm_oblock_t invalidate_oblock; | |
514 | }; | |
515 | ||
516 | /*----------------------------------------------------------------*/ | |
517 | ||
518 | static bool writethrough_mode(struct cache_features *f) | |
519 | { | |
520 | return f->io_mode == CM_IO_WRITETHROUGH; | |
521 | } | |
522 | ||
523 | static bool writeback_mode(struct cache_features *f) | |
524 | { | |
525 | return f->io_mode == CM_IO_WRITEBACK; | |
526 | } | |
527 | ||
528 | static inline bool passthrough_mode(struct cache_features *f) | |
529 | { | |
530 | return unlikely(f->io_mode == CM_IO_PASSTHROUGH); | |
531 | } | |
532 | ||
533 | /*----------------------------------------------------------------*/ | |
534 | ||
535 | static void wake_deferred_bio_worker(struct cache *cache) | |
536 | { | |
537 | queue_work(cache->wq, &cache->deferred_bio_worker); | |
538 | } | |
539 | ||
540 | static void wake_deferred_writethrough_worker(struct cache *cache) | |
541 | { | |
542 | queue_work(cache->wq, &cache->deferred_writethrough_worker); | |
543 | } | |
544 | ||
545 | static void wake_migration_worker(struct cache *cache) | |
546 | { | |
547 | if (passthrough_mode(&cache->features)) | |
548 | return; | |
549 | ||
550 | queue_work(cache->wq, &cache->migration_worker); | |
551 | } | |
552 | ||
553 | /*----------------------------------------------------------------*/ | |
554 | ||
555 | static struct dm_bio_prison_cell_v2 *alloc_prison_cell(struct cache *cache) | |
556 | { | |
557 | return dm_bio_prison_alloc_cell_v2(cache->prison, GFP_NOWAIT); | |
558 | } | |
559 | ||
560 | static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell_v2 *cell) | |
561 | { | |
562 | dm_bio_prison_free_cell_v2(cache->prison, cell); | |
563 | } | |
564 | ||
565 | static struct dm_cache_migration *alloc_migration(struct cache *cache) | |
566 | { | |
567 | struct dm_cache_migration *mg; | |
568 | ||
569 | mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT); | |
570 | if (mg) { | |
571 | mg->cache = cache; | |
572 | atomic_inc(&mg->cache->nr_allocated_migrations); | |
573 | } | |
574 | ||
575 | return mg; | |
576 | } | |
577 | ||
578 | static void free_migration(struct dm_cache_migration *mg) | |
579 | { | |
580 | struct cache *cache = mg->cache; | |
581 | ||
582 | if (atomic_dec_and_test(&cache->nr_allocated_migrations)) | |
583 | wake_up(&cache->migration_wait); | |
584 | ||
585 | mempool_free(mg, cache->migration_pool); | |
586 | } | |
587 | ||
588 | /*----------------------------------------------------------------*/ | |
589 | ||
590 | static inline dm_oblock_t oblock_succ(dm_oblock_t b) | |
591 | { | |
592 | return to_oblock(from_oblock(b) + 1ull); | |
593 | } | |
594 | ||
595 | static void build_key(dm_oblock_t begin, dm_oblock_t end, struct dm_cell_key_v2 *key) | |
596 | { | |
597 | key->virtual = 0; | |
598 | key->dev = 0; | |
599 | key->block_begin = from_oblock(begin); | |
600 | key->block_end = from_oblock(end); | |
601 | } | |
602 | ||
603 | /* | |
604 | * We have two lock levels. Level 0, which is used to prevent WRITEs, and | |
605 | * level 1 which prevents *both* READs and WRITEs. | |
606 | */ | |
607 | #define WRITE_LOCK_LEVEL 0 | |
608 | #define READ_WRITE_LOCK_LEVEL 1 | |
609 | ||
610 | static unsigned lock_level(struct bio *bio) | |
611 | { | |
612 | return bio_data_dir(bio) == WRITE ? | |
613 | WRITE_LOCK_LEVEL : | |
614 | READ_WRITE_LOCK_LEVEL; | |
615 | } | |
616 | ||
617 | /*---------------------------------------------------------------- | |
618 | * Per bio data | |
619 | *--------------------------------------------------------------*/ | |
620 | ||
621 | /* | |
622 | * If using writeback, leave out struct per_bio_data's writethrough fields. | |
623 | */ | |
624 | #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) | |
625 | #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) | |
626 | ||
627 | static size_t get_per_bio_data_size(struct cache *cache) | |
628 | { | |
629 | return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; | |
630 | } | |
631 | ||
632 | static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size) | |
633 | { | |
634 | struct per_bio_data *pb = dm_per_bio_data(bio, data_size); | |
635 | BUG_ON(!pb); | |
636 | return pb; | |
637 | } | |
638 | ||
639 | static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size) | |
640 | { | |
641 | struct per_bio_data *pb = get_per_bio_data(bio, data_size); | |
642 | ||
643 | pb->tick = false; | |
644 | pb->req_nr = dm_bio_get_target_bio_nr(bio); | |
645 | pb->cell = NULL; | |
646 | pb->len = 0; | |
647 | ||
648 | return pb; | |
649 | } | |
650 | ||
651 | /*----------------------------------------------------------------*/ | |
652 | ||
653 | static void defer_bio(struct cache *cache, struct bio *bio) | |
654 | { | |
655 | unsigned long flags; | |
656 | ||
657 | spin_lock_irqsave(&cache->lock, flags); | |
658 | bio_list_add(&cache->deferred_bios, bio); | |
659 | spin_unlock_irqrestore(&cache->lock, flags); | |
660 | ||
661 | wake_deferred_bio_worker(cache); | |
662 | } | |
663 | ||
664 | static void defer_bios(struct cache *cache, struct bio_list *bios) | |
665 | { | |
666 | unsigned long flags; | |
667 | ||
668 | spin_lock_irqsave(&cache->lock, flags); | |
669 | bio_list_merge(&cache->deferred_bios, bios); | |
670 | bio_list_init(bios); | |
671 | spin_unlock_irqrestore(&cache->lock, flags); | |
672 | ||
673 | wake_deferred_bio_worker(cache); | |
674 | } | |
675 | ||
676 | /*----------------------------------------------------------------*/ | |
677 | ||
678 | static bool bio_detain_shared(struct cache *cache, dm_oblock_t oblock, struct bio *bio) | |
679 | { | |
680 | bool r; | |
681 | size_t pb_size; | |
682 | struct per_bio_data *pb; | |
683 | struct dm_cell_key_v2 key; | |
684 | dm_oblock_t end = to_oblock(from_oblock(oblock) + 1ULL); | |
685 | struct dm_bio_prison_cell_v2 *cell_prealloc, *cell; | |
686 | ||
687 | cell_prealloc = alloc_prison_cell(cache); /* FIXME: allow wait if calling from worker */ | |
688 | if (!cell_prealloc) { | |
689 | defer_bio(cache, bio); | |
690 | return false; | |
691 | } | |
692 | ||
693 | build_key(oblock, end, &key); | |
694 | r = dm_cell_get_v2(cache->prison, &key, lock_level(bio), bio, cell_prealloc, &cell); | |
695 | if (!r) { | |
696 | /* | |
697 | * Failed to get the lock. | |
698 | */ | |
699 | free_prison_cell(cache, cell_prealloc); | |
700 | return r; | |
701 | } | |
702 | ||
703 | if (cell != cell_prealloc) | |
704 | free_prison_cell(cache, cell_prealloc); | |
705 | ||
706 | pb_size = get_per_bio_data_size(cache); | |
707 | pb = get_per_bio_data(bio, pb_size); | |
708 | pb->cell = cell; | |
709 | ||
710 | return r; | |
711 | } | |
712 | ||
713 | /*----------------------------------------------------------------*/ | |
714 | ||
715 | static bool is_dirty(struct cache *cache, dm_cblock_t b) | |
716 | { | |
717 | return test_bit(from_cblock(b), cache->dirty_bitset); | |
718 | } | |
719 | ||
720 | static void set_dirty(struct cache *cache, dm_cblock_t cblock) | |
721 | { | |
722 | if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
723 | atomic_inc(&cache->nr_dirty); | |
724 | policy_set_dirty(cache->policy, cblock); | |
725 | } | |
726 | } | |
727 | ||
728 | /* | |
729 | * These two are called when setting after migrations to force the policy | |
730 | * and dirty bitset to be in sync. | |
731 | */ | |
732 | static void force_set_dirty(struct cache *cache, dm_cblock_t cblock) | |
733 | { | |
734 | if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) | |
735 | atomic_inc(&cache->nr_dirty); | |
736 | policy_set_dirty(cache->policy, cblock); | |
737 | } | |
738 | ||
739 | static void force_clear_dirty(struct cache *cache, dm_cblock_t cblock) | |
740 | { | |
741 | if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
742 | if (atomic_dec_return(&cache->nr_dirty) == 0) | |
743 | dm_table_event(cache->ti->table); | |
744 | } | |
745 | ||
746 | policy_clear_dirty(cache->policy, cblock); | |
747 | } | |
748 | ||
749 | /*----------------------------------------------------------------*/ | |
750 | ||
751 | static bool block_size_is_power_of_two(struct cache *cache) | |
752 | { | |
753 | return cache->sectors_per_block_shift >= 0; | |
754 | } | |
755 | ||
756 | /* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */ | |
757 | #if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6 | |
758 | __always_inline | |
759 | #endif | |
760 | static dm_block_t block_div(dm_block_t b, uint32_t n) | |
761 | { | |
762 | do_div(b, n); | |
763 | ||
764 | return b; | |
765 | } | |
766 | ||
767 | static dm_block_t oblocks_per_dblock(struct cache *cache) | |
768 | { | |
769 | dm_block_t oblocks = cache->discard_block_size; | |
770 | ||
771 | if (block_size_is_power_of_two(cache)) | |
772 | oblocks >>= cache->sectors_per_block_shift; | |
773 | else | |
774 | oblocks = block_div(oblocks, cache->sectors_per_block); | |
775 | ||
776 | return oblocks; | |
777 | } | |
778 | ||
779 | static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) | |
780 | { | |
781 | return to_dblock(block_div(from_oblock(oblock), | |
782 | oblocks_per_dblock(cache))); | |
783 | } | |
784 | ||
785 | static void set_discard(struct cache *cache, dm_dblock_t b) | |
786 | { | |
787 | unsigned long flags; | |
788 | ||
789 | BUG_ON(from_dblock(b) >= from_dblock(cache->discard_nr_blocks)); | |
790 | atomic_inc(&cache->stats.discard_count); | |
791 | ||
792 | spin_lock_irqsave(&cache->lock, flags); | |
793 | set_bit(from_dblock(b), cache->discard_bitset); | |
794 | spin_unlock_irqrestore(&cache->lock, flags); | |
795 | } | |
796 | ||
797 | static void clear_discard(struct cache *cache, dm_dblock_t b) | |
798 | { | |
799 | unsigned long flags; | |
800 | ||
801 | spin_lock_irqsave(&cache->lock, flags); | |
802 | clear_bit(from_dblock(b), cache->discard_bitset); | |
803 | spin_unlock_irqrestore(&cache->lock, flags); | |
804 | } | |
805 | ||
806 | static bool is_discarded(struct cache *cache, dm_dblock_t b) | |
807 | { | |
808 | int r; | |
809 | unsigned long flags; | |
810 | ||
811 | spin_lock_irqsave(&cache->lock, flags); | |
812 | r = test_bit(from_dblock(b), cache->discard_bitset); | |
813 | spin_unlock_irqrestore(&cache->lock, flags); | |
814 | ||
815 | return r; | |
816 | } | |
817 | ||
818 | static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) | |
819 | { | |
820 | int r; | |
821 | unsigned long flags; | |
822 | ||
823 | spin_lock_irqsave(&cache->lock, flags); | |
824 | r = test_bit(from_dblock(oblock_to_dblock(cache, b)), | |
825 | cache->discard_bitset); | |
826 | spin_unlock_irqrestore(&cache->lock, flags); | |
827 | ||
828 | return r; | |
829 | } | |
830 | ||
831 | /*---------------------------------------------------------------- | |
832 | * Remapping | |
833 | *--------------------------------------------------------------*/ | |
834 | static void remap_to_origin(struct cache *cache, struct bio *bio) | |
835 | { | |
836 | bio_set_dev(bio, cache->origin_dev->bdev); | |
837 | } | |
838 | ||
839 | static void remap_to_cache(struct cache *cache, struct bio *bio, | |
840 | dm_cblock_t cblock) | |
841 | { | |
842 | sector_t bi_sector = bio->bi_iter.bi_sector; | |
843 | sector_t block = from_cblock(cblock); | |
844 | ||
845 | bio_set_dev(bio, cache->cache_dev->bdev); | |
846 | if (!block_size_is_power_of_two(cache)) | |
847 | bio->bi_iter.bi_sector = | |
848 | (block * cache->sectors_per_block) + | |
849 | sector_div(bi_sector, cache->sectors_per_block); | |
850 | else | |
851 | bio->bi_iter.bi_sector = | |
852 | (block << cache->sectors_per_block_shift) | | |
853 | (bi_sector & (cache->sectors_per_block - 1)); | |
854 | } | |
855 | ||
856 | static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) | |
857 | { | |
858 | unsigned long flags; | |
859 | size_t pb_data_size = get_per_bio_data_size(cache); | |
860 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
861 | ||
862 | spin_lock_irqsave(&cache->lock, flags); | |
863 | if (cache->need_tick_bio && !op_is_flush(bio->bi_opf) && | |
864 | bio_op(bio) != REQ_OP_DISCARD) { | |
865 | pb->tick = true; | |
866 | cache->need_tick_bio = false; | |
867 | } | |
868 | spin_unlock_irqrestore(&cache->lock, flags); | |
869 | } | |
870 | ||
871 | static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, | |
872 | dm_oblock_t oblock) | |
873 | { | |
874 | // FIXME: this is called way too much. | |
875 | check_if_tick_bio_needed(cache, bio); | |
876 | remap_to_origin(cache, bio); | |
877 | if (bio_data_dir(bio) == WRITE) | |
878 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | |
879 | } | |
880 | ||
881 | static void remap_to_cache_dirty(struct cache *cache, struct bio *bio, | |
882 | dm_oblock_t oblock, dm_cblock_t cblock) | |
883 | { | |
884 | check_if_tick_bio_needed(cache, bio); | |
885 | remap_to_cache(cache, bio, cblock); | |
886 | if (bio_data_dir(bio) == WRITE) { | |
887 | set_dirty(cache, cblock); | |
888 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | |
889 | } | |
890 | } | |
891 | ||
892 | static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) | |
893 | { | |
894 | sector_t block_nr = bio->bi_iter.bi_sector; | |
895 | ||
896 | if (!block_size_is_power_of_two(cache)) | |
897 | (void) sector_div(block_nr, cache->sectors_per_block); | |
898 | else | |
899 | block_nr >>= cache->sectors_per_block_shift; | |
900 | ||
901 | return to_oblock(block_nr); | |
902 | } | |
903 | ||
904 | static bool accountable_bio(struct cache *cache, struct bio *bio) | |
905 | { | |
906 | return bio_op(bio) != REQ_OP_DISCARD; | |
907 | } | |
908 | ||
909 | static void accounted_begin(struct cache *cache, struct bio *bio) | |
910 | { | |
911 | size_t pb_data_size = get_per_bio_data_size(cache); | |
912 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
913 | ||
914 | if (accountable_bio(cache, bio)) { | |
915 | pb->len = bio_sectors(bio); | |
916 | iot_io_begin(&cache->tracker, pb->len); | |
917 | } | |
918 | } | |
919 | ||
920 | static void accounted_complete(struct cache *cache, struct bio *bio) | |
921 | { | |
922 | size_t pb_data_size = get_per_bio_data_size(cache); | |
923 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
924 | ||
925 | iot_io_end(&cache->tracker, pb->len); | |
926 | } | |
927 | ||
928 | static void accounted_request(struct cache *cache, struct bio *bio) | |
929 | { | |
930 | accounted_begin(cache, bio); | |
931 | generic_make_request(bio); | |
932 | } | |
933 | ||
934 | static void issue_op(struct bio *bio, void *context) | |
935 | { | |
936 | struct cache *cache = context; | |
937 | accounted_request(cache, bio); | |
938 | } | |
939 | ||
940 | static void defer_writethrough_bio(struct cache *cache, struct bio *bio) | |
941 | { | |
942 | unsigned long flags; | |
943 | ||
944 | spin_lock_irqsave(&cache->lock, flags); | |
945 | bio_list_add(&cache->deferred_writethrough_bios, bio); | |
946 | spin_unlock_irqrestore(&cache->lock, flags); | |
947 | ||
948 | wake_deferred_writethrough_worker(cache); | |
949 | } | |
950 | ||
951 | static void writethrough_endio(struct bio *bio) | |
952 | { | |
953 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); | |
954 | ||
955 | dm_unhook_bio(&pb->hook_info, bio); | |
956 | ||
957 | if (bio->bi_status) { | |
958 | bio_endio(bio); | |
959 | return; | |
960 | } | |
961 | ||
962 | dm_bio_restore(&pb->bio_details, bio); | |
963 | remap_to_cache(pb->cache, bio, pb->cblock); | |
964 | ||
965 | /* | |
966 | * We can't issue this bio directly, since we're in interrupt | |
967 | * context. So it gets put on a bio list for processing by the | |
968 | * worker thread. | |
969 | */ | |
970 | defer_writethrough_bio(pb->cache, bio); | |
971 | } | |
972 | ||
973 | /* | |
974 | * FIXME: send in parallel, huge latency as is. | |
975 | * When running in writethrough mode we need to send writes to clean blocks | |
976 | * to both the cache and origin devices. In future we'd like to clone the | |
977 | * bio and send them in parallel, but for now we're doing them in | |
978 | * series as this is easier. | |
979 | */ | |
980 | static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, | |
981 | dm_oblock_t oblock, dm_cblock_t cblock) | |
982 | { | |
983 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); | |
984 | ||
985 | pb->cache = cache; | |
986 | pb->cblock = cblock; | |
987 | dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL); | |
988 | dm_bio_record(&pb->bio_details, bio); | |
989 | ||
990 | remap_to_origin_clear_discard(pb->cache, bio, oblock); | |
991 | } | |
992 | ||
993 | /*---------------------------------------------------------------- | |
994 | * Failure modes | |
995 | *--------------------------------------------------------------*/ | |
996 | static enum cache_metadata_mode get_cache_mode(struct cache *cache) | |
997 | { | |
998 | return cache->features.mode; | |
999 | } | |
1000 | ||
1001 | static const char *cache_device_name(struct cache *cache) | |
1002 | { | |
1003 | return dm_device_name(dm_table_get_md(cache->ti->table)); | |
1004 | } | |
1005 | ||
1006 | static void notify_mode_switch(struct cache *cache, enum cache_metadata_mode mode) | |
1007 | { | |
1008 | const char *descs[] = { | |
1009 | "write", | |
1010 | "read-only", | |
1011 | "fail" | |
1012 | }; | |
1013 | ||
1014 | dm_table_event(cache->ti->table); | |
1015 | DMINFO("%s: switching cache to %s mode", | |
1016 | cache_device_name(cache), descs[(int)mode]); | |
1017 | } | |
1018 | ||
1019 | static void set_cache_mode(struct cache *cache, enum cache_metadata_mode new_mode) | |
1020 | { | |
1021 | bool needs_check; | |
1022 | enum cache_metadata_mode old_mode = get_cache_mode(cache); | |
1023 | ||
1024 | if (dm_cache_metadata_needs_check(cache->cmd, &needs_check)) { | |
1025 | DMERR("%s: unable to read needs_check flag, setting failure mode.", | |
1026 | cache_device_name(cache)); | |
1027 | new_mode = CM_FAIL; | |
1028 | } | |
1029 | ||
1030 | if (new_mode == CM_WRITE && needs_check) { | |
1031 | DMERR("%s: unable to switch cache to write mode until repaired.", | |
1032 | cache_device_name(cache)); | |
1033 | if (old_mode != new_mode) | |
1034 | new_mode = old_mode; | |
1035 | else | |
1036 | new_mode = CM_READ_ONLY; | |
1037 | } | |
1038 | ||
1039 | /* Never move out of fail mode */ | |
1040 | if (old_mode == CM_FAIL) | |
1041 | new_mode = CM_FAIL; | |
1042 | ||
1043 | switch (new_mode) { | |
1044 | case CM_FAIL: | |
1045 | case CM_READ_ONLY: | |
1046 | dm_cache_metadata_set_read_only(cache->cmd); | |
1047 | break; | |
1048 | ||
1049 | case CM_WRITE: | |
1050 | dm_cache_metadata_set_read_write(cache->cmd); | |
1051 | break; | |
1052 | } | |
1053 | ||
1054 | cache->features.mode = new_mode; | |
1055 | ||
1056 | if (new_mode != old_mode) | |
1057 | notify_mode_switch(cache, new_mode); | |
1058 | } | |
1059 | ||
1060 | static void abort_transaction(struct cache *cache) | |
1061 | { | |
1062 | const char *dev_name = cache_device_name(cache); | |
1063 | ||
1064 | if (get_cache_mode(cache) >= CM_READ_ONLY) | |
1065 | return; | |
1066 | ||
1067 | if (dm_cache_metadata_set_needs_check(cache->cmd)) { | |
1068 | DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name); | |
1069 | set_cache_mode(cache, CM_FAIL); | |
1070 | } | |
1071 | ||
1072 | DMERR_LIMIT("%s: aborting current metadata transaction", dev_name); | |
1073 | if (dm_cache_metadata_abort(cache->cmd)) { | |
1074 | DMERR("%s: failed to abort metadata transaction", dev_name); | |
1075 | set_cache_mode(cache, CM_FAIL); | |
1076 | } | |
1077 | } | |
1078 | ||
1079 | static void metadata_operation_failed(struct cache *cache, const char *op, int r) | |
1080 | { | |
1081 | DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d", | |
1082 | cache_device_name(cache), op, r); | |
1083 | abort_transaction(cache); | |
1084 | set_cache_mode(cache, CM_READ_ONLY); | |
1085 | } | |
1086 | ||
1087 | /*----------------------------------------------------------------*/ | |
1088 | ||
1089 | static void load_stats(struct cache *cache) | |
1090 | { | |
1091 | struct dm_cache_statistics stats; | |
1092 | ||
1093 | dm_cache_metadata_get_stats(cache->cmd, &stats); | |
1094 | atomic_set(&cache->stats.read_hit, stats.read_hits); | |
1095 | atomic_set(&cache->stats.read_miss, stats.read_misses); | |
1096 | atomic_set(&cache->stats.write_hit, stats.write_hits); | |
1097 | atomic_set(&cache->stats.write_miss, stats.write_misses); | |
1098 | } | |
1099 | ||
1100 | static void save_stats(struct cache *cache) | |
1101 | { | |
1102 | struct dm_cache_statistics stats; | |
1103 | ||
1104 | if (get_cache_mode(cache) >= CM_READ_ONLY) | |
1105 | return; | |
1106 | ||
1107 | stats.read_hits = atomic_read(&cache->stats.read_hit); | |
1108 | stats.read_misses = atomic_read(&cache->stats.read_miss); | |
1109 | stats.write_hits = atomic_read(&cache->stats.write_hit); | |
1110 | stats.write_misses = atomic_read(&cache->stats.write_miss); | |
1111 | ||
1112 | dm_cache_metadata_set_stats(cache->cmd, &stats); | |
1113 | } | |
1114 | ||
1115 | static void update_stats(struct cache_stats *stats, enum policy_operation op) | |
1116 | { | |
1117 | switch (op) { | |
1118 | case POLICY_PROMOTE: | |
1119 | atomic_inc(&stats->promotion); | |
1120 | break; | |
1121 | ||
1122 | case POLICY_DEMOTE: | |
1123 | atomic_inc(&stats->demotion); | |
1124 | break; | |
1125 | ||
1126 | case POLICY_WRITEBACK: | |
1127 | atomic_inc(&stats->writeback); | |
1128 | break; | |
1129 | } | |
1130 | } | |
1131 | ||
1132 | /*---------------------------------------------------------------- | |
1133 | * Migration processing | |
1134 | * | |
1135 | * Migration covers moving data from the origin device to the cache, or | |
1136 | * vice versa. | |
1137 | *--------------------------------------------------------------*/ | |
1138 | ||
1139 | static void inc_io_migrations(struct cache *cache) | |
1140 | { | |
1141 | atomic_inc(&cache->nr_io_migrations); | |
1142 | } | |
1143 | ||
1144 | static void dec_io_migrations(struct cache *cache) | |
1145 | { | |
1146 | atomic_dec(&cache->nr_io_migrations); | |
1147 | } | |
1148 | ||
1149 | static bool discard_or_flush(struct bio *bio) | |
1150 | { | |
1151 | return bio_op(bio) == REQ_OP_DISCARD || op_is_flush(bio->bi_opf); | |
1152 | } | |
1153 | ||
1154 | static void calc_discard_block_range(struct cache *cache, struct bio *bio, | |
1155 | dm_dblock_t *b, dm_dblock_t *e) | |
1156 | { | |
1157 | sector_t sb = bio->bi_iter.bi_sector; | |
1158 | sector_t se = bio_end_sector(bio); | |
1159 | ||
1160 | *b = to_dblock(dm_sector_div_up(sb, cache->discard_block_size)); | |
1161 | ||
1162 | if (se - sb < cache->discard_block_size) | |
1163 | *e = *b; | |
1164 | else | |
1165 | *e = to_dblock(block_div(se, cache->discard_block_size)); | |
1166 | } | |
1167 | ||
1168 | /*----------------------------------------------------------------*/ | |
1169 | ||
1170 | static void prevent_background_work(struct cache *cache) | |
1171 | { | |
1172 | lockdep_off(); | |
1173 | down_write(&cache->background_work_lock); | |
1174 | lockdep_on(); | |
1175 | } | |
1176 | ||
1177 | static void allow_background_work(struct cache *cache) | |
1178 | { | |
1179 | lockdep_off(); | |
1180 | up_write(&cache->background_work_lock); | |
1181 | lockdep_on(); | |
1182 | } | |
1183 | ||
1184 | static bool background_work_begin(struct cache *cache) | |
1185 | { | |
1186 | bool r; | |
1187 | ||
1188 | lockdep_off(); | |
1189 | r = down_read_trylock(&cache->background_work_lock); | |
1190 | lockdep_on(); | |
1191 | ||
1192 | return r; | |
1193 | } | |
1194 | ||
1195 | static void background_work_end(struct cache *cache) | |
1196 | { | |
1197 | lockdep_off(); | |
1198 | up_read(&cache->background_work_lock); | |
1199 | lockdep_on(); | |
1200 | } | |
1201 | ||
1202 | /*----------------------------------------------------------------*/ | |
1203 | ||
1204 | static void quiesce(struct dm_cache_migration *mg, | |
1205 | void (*continuation)(struct work_struct *)) | |
1206 | { | |
1207 | init_continuation(&mg->k, continuation); | |
1208 | dm_cell_quiesce_v2(mg->cache->prison, mg->cell, &mg->k.ws); | |
1209 | } | |
1210 | ||
1211 | static struct dm_cache_migration *ws_to_mg(struct work_struct *ws) | |
1212 | { | |
1213 | struct continuation *k = container_of(ws, struct continuation, ws); | |
1214 | return container_of(k, struct dm_cache_migration, k); | |
1215 | } | |
1216 | ||
1217 | static void copy_complete(int read_err, unsigned long write_err, void *context) | |
1218 | { | |
1219 | struct dm_cache_migration *mg = container_of(context, struct dm_cache_migration, k); | |
1220 | ||
1221 | if (read_err || write_err) | |
1222 | mg->k.input = BLK_STS_IOERR; | |
1223 | ||
1224 | queue_continuation(mg->cache->wq, &mg->k); | |
1225 | } | |
1226 | ||
1227 | static int copy(struct dm_cache_migration *mg, bool promote) | |
1228 | { | |
1229 | int r; | |
1230 | struct dm_io_region o_region, c_region; | |
1231 | struct cache *cache = mg->cache; | |
1232 | ||
1233 | o_region.bdev = cache->origin_dev->bdev; | |
1234 | o_region.sector = from_oblock(mg->op->oblock) * cache->sectors_per_block; | |
1235 | o_region.count = cache->sectors_per_block; | |
1236 | ||
1237 | c_region.bdev = cache->cache_dev->bdev; | |
1238 | c_region.sector = from_cblock(mg->op->cblock) * cache->sectors_per_block; | |
1239 | c_region.count = cache->sectors_per_block; | |
1240 | ||
1241 | if (promote) | |
1242 | r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, &mg->k); | |
1243 | else | |
1244 | r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, &mg->k); | |
1245 | ||
1246 | return r; | |
1247 | } | |
1248 | ||
1249 | static void bio_drop_shared_lock(struct cache *cache, struct bio *bio) | |
1250 | { | |
1251 | size_t pb_data_size = get_per_bio_data_size(cache); | |
1252 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
1253 | ||
1254 | if (pb->cell && dm_cell_put_v2(cache->prison, pb->cell)) | |
1255 | free_prison_cell(cache, pb->cell); | |
1256 | pb->cell = NULL; | |
1257 | } | |
1258 | ||
1259 | static void overwrite_endio(struct bio *bio) | |
1260 | { | |
1261 | struct dm_cache_migration *mg = bio->bi_private; | |
1262 | struct cache *cache = mg->cache; | |
1263 | size_t pb_data_size = get_per_bio_data_size(cache); | |
1264 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
1265 | ||
1266 | dm_unhook_bio(&pb->hook_info, bio); | |
1267 | ||
1268 | if (bio->bi_status) | |
1269 | mg->k.input = bio->bi_status; | |
1270 | ||
1271 | queue_continuation(mg->cache->wq, &mg->k); | |
1272 | } | |
1273 | ||
1274 | static void overwrite(struct dm_cache_migration *mg, | |
1275 | void (*continuation)(struct work_struct *)) | |
1276 | { | |
1277 | struct bio *bio = mg->overwrite_bio; | |
1278 | size_t pb_data_size = get_per_bio_data_size(mg->cache); | |
1279 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
1280 | ||
1281 | dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg); | |
1282 | ||
1283 | /* | |
1284 | * The overwrite bio is part of the copy operation, as such it does | |
1285 | * not set/clear discard or dirty flags. | |
1286 | */ | |
1287 | if (mg->op->op == POLICY_PROMOTE) | |
1288 | remap_to_cache(mg->cache, bio, mg->op->cblock); | |
1289 | else | |
1290 | remap_to_origin(mg->cache, bio); | |
1291 | ||
1292 | init_continuation(&mg->k, continuation); | |
1293 | accounted_request(mg->cache, bio); | |
1294 | } | |
1295 | ||
1296 | /* | |
1297 | * Migration steps: | |
1298 | * | |
1299 | * 1) exclusive lock preventing WRITEs | |
1300 | * 2) quiesce | |
1301 | * 3) copy or issue overwrite bio | |
1302 | * 4) upgrade to exclusive lock preventing READs and WRITEs | |
1303 | * 5) quiesce | |
1304 | * 6) update metadata and commit | |
1305 | * 7) unlock | |
1306 | */ | |
1307 | static void mg_complete(struct dm_cache_migration *mg, bool success) | |
1308 | { | |
1309 | struct bio_list bios; | |
1310 | struct cache *cache = mg->cache; | |
1311 | struct policy_work *op = mg->op; | |
1312 | dm_cblock_t cblock = op->cblock; | |
1313 | ||
1314 | if (success) | |
1315 | update_stats(&cache->stats, op->op); | |
1316 | ||
1317 | switch (op->op) { | |
1318 | case POLICY_PROMOTE: | |
1319 | clear_discard(cache, oblock_to_dblock(cache, op->oblock)); | |
1320 | policy_complete_background_work(cache->policy, op, success); | |
1321 | ||
1322 | if (mg->overwrite_bio) { | |
1323 | if (success) | |
1324 | force_set_dirty(cache, cblock); | |
1325 | else if (mg->k.input) | |
1326 | mg->overwrite_bio->bi_status = mg->k.input; | |
1327 | else | |
1328 | mg->overwrite_bio->bi_status = BLK_STS_IOERR; | |
1329 | bio_endio(mg->overwrite_bio); | |
1330 | } else { | |
1331 | if (success) | |
1332 | force_clear_dirty(cache, cblock); | |
1333 | dec_io_migrations(cache); | |
1334 | } | |
1335 | break; | |
1336 | ||
1337 | case POLICY_DEMOTE: | |
1338 | /* | |
1339 | * We clear dirty here to update the nr_dirty counter. | |
1340 | */ | |
1341 | if (success) | |
1342 | force_clear_dirty(cache, cblock); | |
1343 | policy_complete_background_work(cache->policy, op, success); | |
1344 | dec_io_migrations(cache); | |
1345 | break; | |
1346 | ||
1347 | case POLICY_WRITEBACK: | |
1348 | if (success) | |
1349 | force_clear_dirty(cache, cblock); | |
1350 | policy_complete_background_work(cache->policy, op, success); | |
1351 | dec_io_migrations(cache); | |
1352 | break; | |
1353 | } | |
1354 | ||
1355 | bio_list_init(&bios); | |
1356 | if (mg->cell) { | |
1357 | if (dm_cell_unlock_v2(cache->prison, mg->cell, &bios)) | |
1358 | free_prison_cell(cache, mg->cell); | |
1359 | } | |
1360 | ||
1361 | free_migration(mg); | |
1362 | defer_bios(cache, &bios); | |
1363 | wake_migration_worker(cache); | |
1364 | ||
1365 | background_work_end(cache); | |
1366 | } | |
1367 | ||
1368 | static void mg_success(struct work_struct *ws) | |
1369 | { | |
1370 | struct dm_cache_migration *mg = ws_to_mg(ws); | |
1371 | mg_complete(mg, mg->k.input == 0); | |
1372 | } | |
1373 | ||
1374 | static void mg_update_metadata(struct work_struct *ws) | |
1375 | { | |
1376 | int r; | |
1377 | struct dm_cache_migration *mg = ws_to_mg(ws); | |
1378 | struct cache *cache = mg->cache; | |
1379 | struct policy_work *op = mg->op; | |
1380 | ||
1381 | switch (op->op) { | |
1382 | case POLICY_PROMOTE: | |
1383 | r = dm_cache_insert_mapping(cache->cmd, op->cblock, op->oblock); | |
1384 | if (r) { | |
1385 | DMERR_LIMIT("%s: migration failed; couldn't insert mapping", | |
1386 | cache_device_name(cache)); | |
1387 | metadata_operation_failed(cache, "dm_cache_insert_mapping", r); | |
1388 | ||
1389 | mg_complete(mg, false); | |
1390 | return; | |
1391 | } | |
1392 | mg_complete(mg, true); | |
1393 | break; | |
1394 | ||
1395 | case POLICY_DEMOTE: | |
1396 | r = dm_cache_remove_mapping(cache->cmd, op->cblock); | |
1397 | if (r) { | |
1398 | DMERR_LIMIT("%s: migration failed; couldn't update on disk metadata", | |
1399 | cache_device_name(cache)); | |
1400 | metadata_operation_failed(cache, "dm_cache_remove_mapping", r); | |
1401 | ||
1402 | mg_complete(mg, false); | |
1403 | return; | |
1404 | } | |
1405 | ||
1406 | /* | |
1407 | * It would be nice if we only had to commit when a REQ_FLUSH | |
1408 | * comes through. But there's one scenario that we have to | |
1409 | * look out for: | |
1410 | * | |
1411 | * - vblock x in a cache block | |
1412 | * - domotion occurs | |
1413 | * - cache block gets reallocated and over written | |
1414 | * - crash | |
1415 | * | |
1416 | * When we recover, because there was no commit the cache will | |
1417 | * rollback to having the data for vblock x in the cache block. | |
1418 | * But the cache block has since been overwritten, so it'll end | |
1419 | * up pointing to data that was never in 'x' during the history | |
1420 | * of the device. | |
1421 | * | |
1422 | * To avoid this issue we require a commit as part of the | |
1423 | * demotion operation. | |
1424 | */ | |
1425 | init_continuation(&mg->k, mg_success); | |
1426 | continue_after_commit(&cache->committer, &mg->k); | |
1427 | schedule_commit(&cache->committer); | |
1428 | break; | |
1429 | ||
1430 | case POLICY_WRITEBACK: | |
1431 | mg_complete(mg, true); | |
1432 | break; | |
1433 | } | |
1434 | } | |
1435 | ||
1436 | static void mg_update_metadata_after_copy(struct work_struct *ws) | |
1437 | { | |
1438 | struct dm_cache_migration *mg = ws_to_mg(ws); | |
1439 | ||
1440 | /* | |
1441 | * Did the copy succeed? | |
1442 | */ | |
1443 | if (mg->k.input) | |
1444 | mg_complete(mg, false); | |
1445 | else | |
1446 | mg_update_metadata(ws); | |
1447 | } | |
1448 | ||
1449 | static void mg_upgrade_lock(struct work_struct *ws) | |
1450 | { | |
1451 | int r; | |
1452 | struct dm_cache_migration *mg = ws_to_mg(ws); | |
1453 | ||
1454 | /* | |
1455 | * Did the copy succeed? | |
1456 | */ | |
1457 | if (mg->k.input) | |
1458 | mg_complete(mg, false); | |
1459 | ||
1460 | else { | |
1461 | /* | |
1462 | * Now we want the lock to prevent both reads and writes. | |
1463 | */ | |
1464 | r = dm_cell_lock_promote_v2(mg->cache->prison, mg->cell, | |
1465 | READ_WRITE_LOCK_LEVEL); | |
1466 | if (r < 0) | |
1467 | mg_complete(mg, false); | |
1468 | ||
1469 | else if (r) | |
1470 | quiesce(mg, mg_update_metadata); | |
1471 | ||
1472 | else | |
1473 | mg_update_metadata(ws); | |
1474 | } | |
1475 | } | |
1476 | ||
1477 | static void mg_copy(struct work_struct *ws) | |
1478 | { | |
1479 | int r; | |
1480 | struct dm_cache_migration *mg = ws_to_mg(ws); | |
1481 | ||
1482 | if (mg->overwrite_bio) { | |
1483 | /* | |
1484 | * It's safe to do this here, even though it's new data | |
1485 | * because all IO has been locked out of the block. | |
1486 | * | |
1487 | * mg_lock_writes() already took READ_WRITE_LOCK_LEVEL | |
1488 | * so _not_ using mg_upgrade_lock() as continutation. | |
1489 | */ | |
1490 | overwrite(mg, mg_update_metadata_after_copy); | |
1491 | ||
1492 | } else { | |
1493 | struct cache *cache = mg->cache; | |
1494 | struct policy_work *op = mg->op; | |
1495 | bool is_policy_promote = (op->op == POLICY_PROMOTE); | |
1496 | ||
1497 | if ((!is_policy_promote && !is_dirty(cache, op->cblock)) || | |
1498 | is_discarded_oblock(cache, op->oblock)) { | |
1499 | mg_upgrade_lock(ws); | |
1500 | return; | |
1501 | } | |
1502 | ||
1503 | init_continuation(&mg->k, mg_upgrade_lock); | |
1504 | ||
1505 | r = copy(mg, is_policy_promote); | |
1506 | if (r) { | |
1507 | DMERR_LIMIT("%s: migration copy failed", cache_device_name(cache)); | |
1508 | mg->k.input = BLK_STS_IOERR; | |
1509 | mg_complete(mg, false); | |
1510 | } | |
1511 | } | |
1512 | } | |
1513 | ||
1514 | static int mg_lock_writes(struct dm_cache_migration *mg) | |
1515 | { | |
1516 | int r; | |
1517 | struct dm_cell_key_v2 key; | |
1518 | struct cache *cache = mg->cache; | |
1519 | struct dm_bio_prison_cell_v2 *prealloc; | |
1520 | ||
1521 | prealloc = alloc_prison_cell(cache); | |
1522 | if (!prealloc) { | |
1523 | DMERR_LIMIT("%s: alloc_prison_cell failed", cache_device_name(cache)); | |
1524 | mg_complete(mg, false); | |
1525 | return -ENOMEM; | |
1526 | } | |
1527 | ||
1528 | /* | |
1529 | * Prevent writes to the block, but allow reads to continue. | |
1530 | * Unless we're using an overwrite bio, in which case we lock | |
1531 | * everything. | |
1532 | */ | |
1533 | build_key(mg->op->oblock, oblock_succ(mg->op->oblock), &key); | |
1534 | r = dm_cell_lock_v2(cache->prison, &key, | |
1535 | mg->overwrite_bio ? READ_WRITE_LOCK_LEVEL : WRITE_LOCK_LEVEL, | |
1536 | prealloc, &mg->cell); | |
1537 | if (r < 0) { | |
1538 | free_prison_cell(cache, prealloc); | |
1539 | mg_complete(mg, false); | |
1540 | return r; | |
1541 | } | |
1542 | ||
1543 | if (mg->cell != prealloc) | |
1544 | free_prison_cell(cache, prealloc); | |
1545 | ||
1546 | if (r == 0) | |
1547 | mg_copy(&mg->k.ws); | |
1548 | else | |
1549 | quiesce(mg, mg_copy); | |
1550 | ||
1551 | return 0; | |
1552 | } | |
1553 | ||
1554 | static int mg_start(struct cache *cache, struct policy_work *op, struct bio *bio) | |
1555 | { | |
1556 | struct dm_cache_migration *mg; | |
1557 | ||
1558 | if (!background_work_begin(cache)) { | |
1559 | policy_complete_background_work(cache->policy, op, false); | |
1560 | return -EPERM; | |
1561 | } | |
1562 | ||
1563 | mg = alloc_migration(cache); | |
1564 | if (!mg) { | |
1565 | policy_complete_background_work(cache->policy, op, false); | |
1566 | background_work_end(cache); | |
1567 | return -ENOMEM; | |
1568 | } | |
1569 | ||
1570 | memset(mg, 0, sizeof(*mg)); | |
1571 | ||
1572 | mg->cache = cache; | |
1573 | mg->op = op; | |
1574 | mg->overwrite_bio = bio; | |
1575 | ||
1576 | if (!bio) | |
1577 | inc_io_migrations(cache); | |
1578 | ||
1579 | return mg_lock_writes(mg); | |
1580 | } | |
1581 | ||
1582 | /*---------------------------------------------------------------- | |
1583 | * invalidation processing | |
1584 | *--------------------------------------------------------------*/ | |
1585 | ||
1586 | static void invalidate_complete(struct dm_cache_migration *mg, bool success) | |
1587 | { | |
1588 | struct bio_list bios; | |
1589 | struct cache *cache = mg->cache; | |
1590 | ||
1591 | bio_list_init(&bios); | |
1592 | if (dm_cell_unlock_v2(cache->prison, mg->cell, &bios)) | |
1593 | free_prison_cell(cache, mg->cell); | |
1594 | ||
1595 | if (!success && mg->overwrite_bio) | |
1596 | bio_io_error(mg->overwrite_bio); | |
1597 | ||
1598 | free_migration(mg); | |
1599 | defer_bios(cache, &bios); | |
1600 | ||
1601 | background_work_end(cache); | |
1602 | } | |
1603 | ||
1604 | static void invalidate_completed(struct work_struct *ws) | |
1605 | { | |
1606 | struct dm_cache_migration *mg = ws_to_mg(ws); | |
1607 | invalidate_complete(mg, !mg->k.input); | |
1608 | } | |
1609 | ||
1610 | static int invalidate_cblock(struct cache *cache, dm_cblock_t cblock) | |
1611 | { | |
1612 | int r = policy_invalidate_mapping(cache->policy, cblock); | |
1613 | if (!r) { | |
1614 | r = dm_cache_remove_mapping(cache->cmd, cblock); | |
1615 | if (r) { | |
1616 | DMERR_LIMIT("%s: invalidation failed; couldn't update on disk metadata", | |
1617 | cache_device_name(cache)); | |
1618 | metadata_operation_failed(cache, "dm_cache_remove_mapping", r); | |
1619 | } | |
1620 | ||
1621 | } else if (r == -ENODATA) { | |
1622 | /* | |
1623 | * Harmless, already unmapped. | |
1624 | */ | |
1625 | r = 0; | |
1626 | ||
1627 | } else | |
1628 | DMERR("%s: policy_invalidate_mapping failed", cache_device_name(cache)); | |
1629 | ||
1630 | return r; | |
1631 | } | |
1632 | ||
1633 | static void invalidate_remove(struct work_struct *ws) | |
1634 | { | |
1635 | int r; | |
1636 | struct dm_cache_migration *mg = ws_to_mg(ws); | |
1637 | struct cache *cache = mg->cache; | |
1638 | ||
1639 | r = invalidate_cblock(cache, mg->invalidate_cblock); | |
1640 | if (r) { | |
1641 | invalidate_complete(mg, false); | |
1642 | return; | |
1643 | } | |
1644 | ||
1645 | init_continuation(&mg->k, invalidate_completed); | |
1646 | continue_after_commit(&cache->committer, &mg->k); | |
1647 | remap_to_origin_clear_discard(cache, mg->overwrite_bio, mg->invalidate_oblock); | |
1648 | mg->overwrite_bio = NULL; | |
1649 | schedule_commit(&cache->committer); | |
1650 | } | |
1651 | ||
1652 | static int invalidate_lock(struct dm_cache_migration *mg) | |
1653 | { | |
1654 | int r; | |
1655 | struct dm_cell_key_v2 key; | |
1656 | struct cache *cache = mg->cache; | |
1657 | struct dm_bio_prison_cell_v2 *prealloc; | |
1658 | ||
1659 | prealloc = alloc_prison_cell(cache); | |
1660 | if (!prealloc) { | |
1661 | invalidate_complete(mg, false); | |
1662 | return -ENOMEM; | |
1663 | } | |
1664 | ||
1665 | build_key(mg->invalidate_oblock, oblock_succ(mg->invalidate_oblock), &key); | |
1666 | r = dm_cell_lock_v2(cache->prison, &key, | |
1667 | READ_WRITE_LOCK_LEVEL, prealloc, &mg->cell); | |
1668 | if (r < 0) { | |
1669 | free_prison_cell(cache, prealloc); | |
1670 | invalidate_complete(mg, false); | |
1671 | return r; | |
1672 | } | |
1673 | ||
1674 | if (mg->cell != prealloc) | |
1675 | free_prison_cell(cache, prealloc); | |
1676 | ||
1677 | if (r) | |
1678 | quiesce(mg, invalidate_remove); | |
1679 | ||
1680 | else { | |
1681 | /* | |
1682 | * We can't call invalidate_remove() directly here because we | |
1683 | * might still be in request context. | |
1684 | */ | |
1685 | init_continuation(&mg->k, invalidate_remove); | |
1686 | queue_work(cache->wq, &mg->k.ws); | |
1687 | } | |
1688 | ||
1689 | return 0; | |
1690 | } | |
1691 | ||
1692 | static int invalidate_start(struct cache *cache, dm_cblock_t cblock, | |
1693 | dm_oblock_t oblock, struct bio *bio) | |
1694 | { | |
1695 | struct dm_cache_migration *mg; | |
1696 | ||
1697 | if (!background_work_begin(cache)) | |
1698 | return -EPERM; | |
1699 | ||
1700 | mg = alloc_migration(cache); | |
1701 | if (!mg) { | |
1702 | background_work_end(cache); | |
1703 | return -ENOMEM; | |
1704 | } | |
1705 | ||
1706 | memset(mg, 0, sizeof(*mg)); | |
1707 | ||
1708 | mg->cache = cache; | |
1709 | mg->overwrite_bio = bio; | |
1710 | mg->invalidate_cblock = cblock; | |
1711 | mg->invalidate_oblock = oblock; | |
1712 | ||
1713 | return invalidate_lock(mg); | |
1714 | } | |
1715 | ||
1716 | /*---------------------------------------------------------------- | |
1717 | * bio processing | |
1718 | *--------------------------------------------------------------*/ | |
1719 | ||
1720 | enum busy { | |
1721 | IDLE, | |
1722 | BUSY | |
1723 | }; | |
1724 | ||
1725 | static enum busy spare_migration_bandwidth(struct cache *cache) | |
1726 | { | |
1727 | bool idle = iot_idle_for(&cache->tracker, HZ); | |
1728 | sector_t current_volume = (atomic_read(&cache->nr_io_migrations) + 1) * | |
1729 | cache->sectors_per_block; | |
1730 | ||
1731 | if (idle && current_volume <= cache->migration_threshold) | |
1732 | return IDLE; | |
1733 | else | |
1734 | return BUSY; | |
1735 | } | |
1736 | ||
1737 | static void inc_hit_counter(struct cache *cache, struct bio *bio) | |
1738 | { | |
1739 | atomic_inc(bio_data_dir(bio) == READ ? | |
1740 | &cache->stats.read_hit : &cache->stats.write_hit); | |
1741 | } | |
1742 | ||
1743 | static void inc_miss_counter(struct cache *cache, struct bio *bio) | |
1744 | { | |
1745 | atomic_inc(bio_data_dir(bio) == READ ? | |
1746 | &cache->stats.read_miss : &cache->stats.write_miss); | |
1747 | } | |
1748 | ||
1749 | /*----------------------------------------------------------------*/ | |
1750 | ||
1751 | static bool bio_writes_complete_block(struct cache *cache, struct bio *bio) | |
1752 | { | |
1753 | return (bio_data_dir(bio) == WRITE) && | |
1754 | (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT)); | |
1755 | } | |
1756 | ||
1757 | static bool optimisable_bio(struct cache *cache, struct bio *bio, dm_oblock_t block) | |
1758 | { | |
1759 | return writeback_mode(&cache->features) && | |
1760 | (is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio)); | |
1761 | } | |
1762 | ||
1763 | static int map_bio(struct cache *cache, struct bio *bio, dm_oblock_t block, | |
1764 | bool *commit_needed) | |
1765 | { | |
1766 | int r, data_dir; | |
1767 | bool rb, background_queued; | |
1768 | dm_cblock_t cblock; | |
1769 | size_t pb_data_size = get_per_bio_data_size(cache); | |
1770 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
1771 | ||
1772 | *commit_needed = false; | |
1773 | ||
1774 | rb = bio_detain_shared(cache, block, bio); | |
1775 | if (!rb) { | |
1776 | /* | |
1777 | * An exclusive lock is held for this block, so we have to | |
1778 | * wait. We set the commit_needed flag so the current | |
1779 | * transaction will be committed asap, allowing this lock | |
1780 | * to be dropped. | |
1781 | */ | |
1782 | *commit_needed = true; | |
1783 | return DM_MAPIO_SUBMITTED; | |
1784 | } | |
1785 | ||
1786 | data_dir = bio_data_dir(bio); | |
1787 | ||
1788 | if (optimisable_bio(cache, bio, block)) { | |
1789 | struct policy_work *op = NULL; | |
1790 | ||
1791 | r = policy_lookup_with_work(cache->policy, block, &cblock, data_dir, true, &op); | |
1792 | if (unlikely(r && r != -ENOENT)) { | |
1793 | DMERR_LIMIT("%s: policy_lookup_with_work() failed with r = %d", | |
1794 | cache_device_name(cache), r); | |
1795 | bio_io_error(bio); | |
1796 | return DM_MAPIO_SUBMITTED; | |
1797 | } | |
1798 | ||
1799 | if (r == -ENOENT && op) { | |
1800 | bio_drop_shared_lock(cache, bio); | |
1801 | BUG_ON(op->op != POLICY_PROMOTE); | |
1802 | mg_start(cache, op, bio); | |
1803 | return DM_MAPIO_SUBMITTED; | |
1804 | } | |
1805 | } else { | |
1806 | r = policy_lookup(cache->policy, block, &cblock, data_dir, false, &background_queued); | |
1807 | if (unlikely(r && r != -ENOENT)) { | |
1808 | DMERR_LIMIT("%s: policy_lookup() failed with r = %d", | |
1809 | cache_device_name(cache), r); | |
1810 | bio_io_error(bio); | |
1811 | return DM_MAPIO_SUBMITTED; | |
1812 | } | |
1813 | ||
1814 | if (background_queued) | |
1815 | wake_migration_worker(cache); | |
1816 | } | |
1817 | ||
1818 | if (r == -ENOENT) { | |
1819 | /* | |
1820 | * Miss. | |
1821 | */ | |
1822 | inc_miss_counter(cache, bio); | |
1823 | if (pb->req_nr == 0) { | |
1824 | accounted_begin(cache, bio); | |
1825 | remap_to_origin_clear_discard(cache, bio, block); | |
1826 | ||
1827 | } else { | |
1828 | /* | |
1829 | * This is a duplicate writethrough io that is no | |
1830 | * longer needed because the block has been demoted. | |
1831 | */ | |
1832 | bio_endio(bio); | |
1833 | return DM_MAPIO_SUBMITTED; | |
1834 | } | |
1835 | } else { | |
1836 | /* | |
1837 | * Hit. | |
1838 | */ | |
1839 | inc_hit_counter(cache, bio); | |
1840 | ||
1841 | /* | |
1842 | * Passthrough always maps to the origin, invalidating any | |
1843 | * cache blocks that are written to. | |
1844 | */ | |
1845 | if (passthrough_mode(&cache->features)) { | |
1846 | if (bio_data_dir(bio) == WRITE) { | |
1847 | bio_drop_shared_lock(cache, bio); | |
1848 | atomic_inc(&cache->stats.demotion); | |
1849 | invalidate_start(cache, cblock, block, bio); | |
1850 | } else | |
1851 | remap_to_origin_clear_discard(cache, bio, block); | |
1852 | ||
1853 | } else { | |
1854 | if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) && | |
1855 | !is_dirty(cache, cblock)) { | |
1856 | remap_to_origin_then_cache(cache, bio, block, cblock); | |
1857 | accounted_begin(cache, bio); | |
1858 | } else | |
1859 | remap_to_cache_dirty(cache, bio, block, cblock); | |
1860 | } | |
1861 | } | |
1862 | ||
1863 | /* | |
1864 | * dm core turns FUA requests into a separate payload and FLUSH req. | |
1865 | */ | |
1866 | if (bio->bi_opf & REQ_FUA) { | |
1867 | /* | |
1868 | * issue_after_commit will call accounted_begin a second time. So | |
1869 | * we call accounted_complete() to avoid double accounting. | |
1870 | */ | |
1871 | accounted_complete(cache, bio); | |
1872 | issue_after_commit(&cache->committer, bio); | |
1873 | *commit_needed = true; | |
1874 | return DM_MAPIO_SUBMITTED; | |
1875 | } | |
1876 | ||
1877 | return DM_MAPIO_REMAPPED; | |
1878 | } | |
1879 | ||
1880 | static bool process_bio(struct cache *cache, struct bio *bio) | |
1881 | { | |
1882 | bool commit_needed; | |
1883 | ||
1884 | if (map_bio(cache, bio, get_bio_block(cache, bio), &commit_needed) == DM_MAPIO_REMAPPED) | |
1885 | generic_make_request(bio); | |
1886 | ||
1887 | return commit_needed; | |
1888 | } | |
1889 | ||
1890 | /* | |
1891 | * A non-zero return indicates read_only or fail_io mode. | |
1892 | */ | |
1893 | static int commit(struct cache *cache, bool clean_shutdown) | |
1894 | { | |
1895 | int r; | |
1896 | ||
1897 | if (get_cache_mode(cache) >= CM_READ_ONLY) | |
1898 | return -EINVAL; | |
1899 | ||
1900 | atomic_inc(&cache->stats.commit_count); | |
1901 | r = dm_cache_commit(cache->cmd, clean_shutdown); | |
1902 | if (r) | |
1903 | metadata_operation_failed(cache, "dm_cache_commit", r); | |
1904 | ||
1905 | return r; | |
1906 | } | |
1907 | ||
1908 | /* | |
1909 | * Used by the batcher. | |
1910 | */ | |
1911 | static blk_status_t commit_op(void *context) | |
1912 | { | |
1913 | struct cache *cache = context; | |
1914 | ||
1915 | if (dm_cache_changed_this_transaction(cache->cmd)) | |
1916 | return errno_to_blk_status(commit(cache, false)); | |
1917 | ||
1918 | return 0; | |
1919 | } | |
1920 | ||
1921 | /*----------------------------------------------------------------*/ | |
1922 | ||
1923 | static bool process_flush_bio(struct cache *cache, struct bio *bio) | |
1924 | { | |
1925 | size_t pb_data_size = get_per_bio_data_size(cache); | |
1926 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
1927 | ||
1928 | if (!pb->req_nr) | |
1929 | remap_to_origin(cache, bio); | |
1930 | else | |
1931 | remap_to_cache(cache, bio, 0); | |
1932 | ||
1933 | issue_after_commit(&cache->committer, bio); | |
1934 | return true; | |
1935 | } | |
1936 | ||
1937 | static bool process_discard_bio(struct cache *cache, struct bio *bio) | |
1938 | { | |
1939 | dm_dblock_t b, e; | |
1940 | ||
1941 | // FIXME: do we need to lock the region? Or can we just assume the | |
1942 | // user wont be so foolish as to issue discard concurrently with | |
1943 | // other IO? | |
1944 | calc_discard_block_range(cache, bio, &b, &e); | |
1945 | while (b != e) { | |
1946 | set_discard(cache, b); | |
1947 | b = to_dblock(from_dblock(b) + 1); | |
1948 | } | |
1949 | ||
1950 | bio_endio(bio); | |
1951 | ||
1952 | return false; | |
1953 | } | |
1954 | ||
1955 | static void process_deferred_bios(struct work_struct *ws) | |
1956 | { | |
1957 | struct cache *cache = container_of(ws, struct cache, deferred_bio_worker); | |
1958 | ||
1959 | unsigned long flags; | |
1960 | bool commit_needed = false; | |
1961 | struct bio_list bios; | |
1962 | struct bio *bio; | |
1963 | ||
1964 | bio_list_init(&bios); | |
1965 | ||
1966 | spin_lock_irqsave(&cache->lock, flags); | |
1967 | bio_list_merge(&bios, &cache->deferred_bios); | |
1968 | bio_list_init(&cache->deferred_bios); | |
1969 | spin_unlock_irqrestore(&cache->lock, flags); | |
1970 | ||
1971 | while ((bio = bio_list_pop(&bios))) { | |
1972 | if (bio->bi_opf & REQ_PREFLUSH) | |
1973 | commit_needed = process_flush_bio(cache, bio) || commit_needed; | |
1974 | ||
1975 | else if (bio_op(bio) == REQ_OP_DISCARD) | |
1976 | commit_needed = process_discard_bio(cache, bio) || commit_needed; | |
1977 | ||
1978 | else | |
1979 | commit_needed = process_bio(cache, bio) || commit_needed; | |
1980 | } | |
1981 | ||
1982 | if (commit_needed) | |
1983 | schedule_commit(&cache->committer); | |
1984 | } | |
1985 | ||
1986 | static void process_deferred_writethrough_bios(struct work_struct *ws) | |
1987 | { | |
1988 | struct cache *cache = container_of(ws, struct cache, deferred_writethrough_worker); | |
1989 | ||
1990 | unsigned long flags; | |
1991 | struct bio_list bios; | |
1992 | struct bio *bio; | |
1993 | ||
1994 | bio_list_init(&bios); | |
1995 | ||
1996 | spin_lock_irqsave(&cache->lock, flags); | |
1997 | bio_list_merge(&bios, &cache->deferred_writethrough_bios); | |
1998 | bio_list_init(&cache->deferred_writethrough_bios); | |
1999 | spin_unlock_irqrestore(&cache->lock, flags); | |
2000 | ||
2001 | /* | |
2002 | * These bios have already been through accounted_begin() | |
2003 | */ | |
2004 | while ((bio = bio_list_pop(&bios))) | |
2005 | generic_make_request(bio); | |
2006 | } | |
2007 | ||
2008 | /*---------------------------------------------------------------- | |
2009 | * Main worker loop | |
2010 | *--------------------------------------------------------------*/ | |
2011 | ||
2012 | static void requeue_deferred_bios(struct cache *cache) | |
2013 | { | |
2014 | struct bio *bio; | |
2015 | struct bio_list bios; | |
2016 | ||
2017 | bio_list_init(&bios); | |
2018 | bio_list_merge(&bios, &cache->deferred_bios); | |
2019 | bio_list_init(&cache->deferred_bios); | |
2020 | ||
2021 | while ((bio = bio_list_pop(&bios))) { | |
2022 | bio->bi_status = BLK_STS_DM_REQUEUE; | |
2023 | bio_endio(bio); | |
2024 | } | |
2025 | } | |
2026 | ||
2027 | /* | |
2028 | * We want to commit periodically so that not too much | |
2029 | * unwritten metadata builds up. | |
2030 | */ | |
2031 | static void do_waker(struct work_struct *ws) | |
2032 | { | |
2033 | struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker); | |
2034 | ||
2035 | policy_tick(cache->policy, true); | |
2036 | wake_migration_worker(cache); | |
2037 | schedule_commit(&cache->committer); | |
2038 | queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); | |
2039 | } | |
2040 | ||
2041 | static void check_migrations(struct work_struct *ws) | |
2042 | { | |
2043 | int r; | |
2044 | struct policy_work *op; | |
2045 | struct cache *cache = container_of(ws, struct cache, migration_worker); | |
2046 | enum busy b; | |
2047 | ||
2048 | for (;;) { | |
2049 | b = spare_migration_bandwidth(cache); | |
2050 | ||
2051 | r = policy_get_background_work(cache->policy, b == IDLE, &op); | |
2052 | if (r == -ENODATA) | |
2053 | break; | |
2054 | ||
2055 | if (r) { | |
2056 | DMERR_LIMIT("%s: policy_background_work failed", | |
2057 | cache_device_name(cache)); | |
2058 | break; | |
2059 | } | |
2060 | ||
2061 | r = mg_start(cache, op, NULL); | |
2062 | if (r) | |
2063 | break; | |
2064 | } | |
2065 | } | |
2066 | ||
2067 | /*---------------------------------------------------------------- | |
2068 | * Target methods | |
2069 | *--------------------------------------------------------------*/ | |
2070 | ||
2071 | /* | |
2072 | * This function gets called on the error paths of the constructor, so we | |
2073 | * have to cope with a partially initialised struct. | |
2074 | */ | |
2075 | static void destroy(struct cache *cache) | |
2076 | { | |
2077 | unsigned i; | |
2078 | ||
2079 | mempool_destroy(cache->migration_pool); | |
2080 | ||
2081 | if (cache->prison) | |
2082 | dm_bio_prison_destroy_v2(cache->prison); | |
2083 | ||
2084 | if (cache->wq) | |
2085 | destroy_workqueue(cache->wq); | |
2086 | ||
2087 | if (cache->dirty_bitset) | |
2088 | free_bitset(cache->dirty_bitset); | |
2089 | ||
2090 | if (cache->discard_bitset) | |
2091 | free_bitset(cache->discard_bitset); | |
2092 | ||
2093 | if (cache->copier) | |
2094 | dm_kcopyd_client_destroy(cache->copier); | |
2095 | ||
2096 | if (cache->cmd) | |
2097 | dm_cache_metadata_close(cache->cmd); | |
2098 | ||
2099 | if (cache->metadata_dev) | |
2100 | dm_put_device(cache->ti, cache->metadata_dev); | |
2101 | ||
2102 | if (cache->origin_dev) | |
2103 | dm_put_device(cache->ti, cache->origin_dev); | |
2104 | ||
2105 | if (cache->cache_dev) | |
2106 | dm_put_device(cache->ti, cache->cache_dev); | |
2107 | ||
2108 | if (cache->policy) | |
2109 | dm_cache_policy_destroy(cache->policy); | |
2110 | ||
2111 | for (i = 0; i < cache->nr_ctr_args ; i++) | |
2112 | kfree(cache->ctr_args[i]); | |
2113 | kfree(cache->ctr_args); | |
2114 | ||
2115 | kfree(cache); | |
2116 | } | |
2117 | ||
2118 | static void cache_dtr(struct dm_target *ti) | |
2119 | { | |
2120 | struct cache *cache = ti->private; | |
2121 | ||
2122 | destroy(cache); | |
2123 | } | |
2124 | ||
2125 | static sector_t get_dev_size(struct dm_dev *dev) | |
2126 | { | |
2127 | return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT; | |
2128 | } | |
2129 | ||
2130 | /*----------------------------------------------------------------*/ | |
2131 | ||
2132 | /* | |
2133 | * Construct a cache device mapping. | |
2134 | * | |
2135 | * cache <metadata dev> <cache dev> <origin dev> <block size> | |
2136 | * <#feature args> [<feature arg>]* | |
2137 | * <policy> <#policy args> [<policy arg>]* | |
2138 | * | |
2139 | * metadata dev : fast device holding the persistent metadata | |
2140 | * cache dev : fast device holding cached data blocks | |
2141 | * origin dev : slow device holding original data blocks | |
2142 | * block size : cache unit size in sectors | |
2143 | * | |
2144 | * #feature args : number of feature arguments passed | |
2145 | * feature args : writethrough. (The default is writeback.) | |
2146 | * | |
2147 | * policy : the replacement policy to use | |
2148 | * #policy args : an even number of policy arguments corresponding | |
2149 | * to key/value pairs passed to the policy | |
2150 | * policy args : key/value pairs passed to the policy | |
2151 | * E.g. 'sequential_threshold 1024' | |
2152 | * See cache-policies.txt for details. | |
2153 | * | |
2154 | * Optional feature arguments are: | |
2155 | * writethrough : write through caching that prohibits cache block | |
2156 | * content from being different from origin block content. | |
2157 | * Without this argument, the default behaviour is to write | |
2158 | * back cache block contents later for performance reasons, | |
2159 | * so they may differ from the corresponding origin blocks. | |
2160 | */ | |
2161 | struct cache_args { | |
2162 | struct dm_target *ti; | |
2163 | ||
2164 | struct dm_dev *metadata_dev; | |
2165 | ||
2166 | struct dm_dev *cache_dev; | |
2167 | sector_t cache_sectors; | |
2168 | ||
2169 | struct dm_dev *origin_dev; | |
2170 | sector_t origin_sectors; | |
2171 | ||
2172 | uint32_t block_size; | |
2173 | ||
2174 | const char *policy_name; | |
2175 | int policy_argc; | |
2176 | const char **policy_argv; | |
2177 | ||
2178 | struct cache_features features; | |
2179 | }; | |
2180 | ||
2181 | static void destroy_cache_args(struct cache_args *ca) | |
2182 | { | |
2183 | if (ca->metadata_dev) | |
2184 | dm_put_device(ca->ti, ca->metadata_dev); | |
2185 | ||
2186 | if (ca->cache_dev) | |
2187 | dm_put_device(ca->ti, ca->cache_dev); | |
2188 | ||
2189 | if (ca->origin_dev) | |
2190 | dm_put_device(ca->ti, ca->origin_dev); | |
2191 | ||
2192 | kfree(ca); | |
2193 | } | |
2194 | ||
2195 | static bool at_least_one_arg(struct dm_arg_set *as, char **error) | |
2196 | { | |
2197 | if (!as->argc) { | |
2198 | *error = "Insufficient args"; | |
2199 | return false; | |
2200 | } | |
2201 | ||
2202 | return true; | |
2203 | } | |
2204 | ||
2205 | static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as, | |
2206 | char **error) | |
2207 | { | |
2208 | int r; | |
2209 | sector_t metadata_dev_size; | |
2210 | char b[BDEVNAME_SIZE]; | |
2211 | ||
2212 | if (!at_least_one_arg(as, error)) | |
2213 | return -EINVAL; | |
2214 | ||
2215 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
2216 | &ca->metadata_dev); | |
2217 | if (r) { | |
2218 | *error = "Error opening metadata device"; | |
2219 | return r; | |
2220 | } | |
2221 | ||
2222 | metadata_dev_size = get_dev_size(ca->metadata_dev); | |
2223 | if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING) | |
2224 | DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", | |
2225 | bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS); | |
2226 | ||
2227 | return 0; | |
2228 | } | |
2229 | ||
2230 | static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as, | |
2231 | char **error) | |
2232 | { | |
2233 | int r; | |
2234 | ||
2235 | if (!at_least_one_arg(as, error)) | |
2236 | return -EINVAL; | |
2237 | ||
2238 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
2239 | &ca->cache_dev); | |
2240 | if (r) { | |
2241 | *error = "Error opening cache device"; | |
2242 | return r; | |
2243 | } | |
2244 | ca->cache_sectors = get_dev_size(ca->cache_dev); | |
2245 | ||
2246 | return 0; | |
2247 | } | |
2248 | ||
2249 | static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, | |
2250 | char **error) | |
2251 | { | |
2252 | int r; | |
2253 | ||
2254 | if (!at_least_one_arg(as, error)) | |
2255 | return -EINVAL; | |
2256 | ||
2257 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
2258 | &ca->origin_dev); | |
2259 | if (r) { | |
2260 | *error = "Error opening origin device"; | |
2261 | return r; | |
2262 | } | |
2263 | ||
2264 | ca->origin_sectors = get_dev_size(ca->origin_dev); | |
2265 | if (ca->ti->len > ca->origin_sectors) { | |
2266 | *error = "Device size larger than cached device"; | |
2267 | return -EINVAL; | |
2268 | } | |
2269 | ||
2270 | return 0; | |
2271 | } | |
2272 | ||
2273 | static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, | |
2274 | char **error) | |
2275 | { | |
2276 | unsigned long block_size; | |
2277 | ||
2278 | if (!at_least_one_arg(as, error)) | |
2279 | return -EINVAL; | |
2280 | ||
2281 | if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size || | |
2282 | block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || | |
2283 | block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || | |
2284 | block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { | |
2285 | *error = "Invalid data block size"; | |
2286 | return -EINVAL; | |
2287 | } | |
2288 | ||
2289 | if (block_size > ca->cache_sectors) { | |
2290 | *error = "Data block size is larger than the cache device"; | |
2291 | return -EINVAL; | |
2292 | } | |
2293 | ||
2294 | ca->block_size = block_size; | |
2295 | ||
2296 | return 0; | |
2297 | } | |
2298 | ||
2299 | static void init_features(struct cache_features *cf) | |
2300 | { | |
2301 | cf->mode = CM_WRITE; | |
2302 | cf->io_mode = CM_IO_WRITEBACK; | |
2303 | cf->metadata_version = 1; | |
2304 | } | |
2305 | ||
2306 | static int parse_features(struct cache_args *ca, struct dm_arg_set *as, | |
2307 | char **error) | |
2308 | { | |
2309 | static const struct dm_arg _args[] = { | |
2310 | {0, 2, "Invalid number of cache feature arguments"}, | |
2311 | }; | |
2312 | ||
2313 | int r; | |
2314 | unsigned argc; | |
2315 | const char *arg; | |
2316 | struct cache_features *cf = &ca->features; | |
2317 | ||
2318 | init_features(cf); | |
2319 | ||
2320 | r = dm_read_arg_group(_args, as, &argc, error); | |
2321 | if (r) | |
2322 | return -EINVAL; | |
2323 | ||
2324 | while (argc--) { | |
2325 | arg = dm_shift_arg(as); | |
2326 | ||
2327 | if (!strcasecmp(arg, "writeback")) | |
2328 | cf->io_mode = CM_IO_WRITEBACK; | |
2329 | ||
2330 | else if (!strcasecmp(arg, "writethrough")) | |
2331 | cf->io_mode = CM_IO_WRITETHROUGH; | |
2332 | ||
2333 | else if (!strcasecmp(arg, "passthrough")) | |
2334 | cf->io_mode = CM_IO_PASSTHROUGH; | |
2335 | ||
2336 | else if (!strcasecmp(arg, "metadata2")) | |
2337 | cf->metadata_version = 2; | |
2338 | ||
2339 | else { | |
2340 | *error = "Unrecognised cache feature requested"; | |
2341 | return -EINVAL; | |
2342 | } | |
2343 | } | |
2344 | ||
2345 | return 0; | |
2346 | } | |
2347 | ||
2348 | static int parse_policy(struct cache_args *ca, struct dm_arg_set *as, | |
2349 | char **error) | |
2350 | { | |
2351 | static const struct dm_arg _args[] = { | |
2352 | {0, 1024, "Invalid number of policy arguments"}, | |
2353 | }; | |
2354 | ||
2355 | int r; | |
2356 | ||
2357 | if (!at_least_one_arg(as, error)) | |
2358 | return -EINVAL; | |
2359 | ||
2360 | ca->policy_name = dm_shift_arg(as); | |
2361 | ||
2362 | r = dm_read_arg_group(_args, as, &ca->policy_argc, error); | |
2363 | if (r) | |
2364 | return -EINVAL; | |
2365 | ||
2366 | ca->policy_argv = (const char **)as->argv; | |
2367 | dm_consume_args(as, ca->policy_argc); | |
2368 | ||
2369 | return 0; | |
2370 | } | |
2371 | ||
2372 | static int parse_cache_args(struct cache_args *ca, int argc, char **argv, | |
2373 | char **error) | |
2374 | { | |
2375 | int r; | |
2376 | struct dm_arg_set as; | |
2377 | ||
2378 | as.argc = argc; | |
2379 | as.argv = argv; | |
2380 | ||
2381 | r = parse_metadata_dev(ca, &as, error); | |
2382 | if (r) | |
2383 | return r; | |
2384 | ||
2385 | r = parse_cache_dev(ca, &as, error); | |
2386 | if (r) | |
2387 | return r; | |
2388 | ||
2389 | r = parse_origin_dev(ca, &as, error); | |
2390 | if (r) | |
2391 | return r; | |
2392 | ||
2393 | r = parse_block_size(ca, &as, error); | |
2394 | if (r) | |
2395 | return r; | |
2396 | ||
2397 | r = parse_features(ca, &as, error); | |
2398 | if (r) | |
2399 | return r; | |
2400 | ||
2401 | r = parse_policy(ca, &as, error); | |
2402 | if (r) | |
2403 | return r; | |
2404 | ||
2405 | return 0; | |
2406 | } | |
2407 | ||
2408 | /*----------------------------------------------------------------*/ | |
2409 | ||
2410 | static struct kmem_cache *migration_cache; | |
2411 | ||
2412 | #define NOT_CORE_OPTION 1 | |
2413 | ||
2414 | static int process_config_option(struct cache *cache, const char *key, const char *value) | |
2415 | { | |
2416 | unsigned long tmp; | |
2417 | ||
2418 | if (!strcasecmp(key, "migration_threshold")) { | |
2419 | if (kstrtoul(value, 10, &tmp)) | |
2420 | return -EINVAL; | |
2421 | ||
2422 | cache->migration_threshold = tmp; | |
2423 | return 0; | |
2424 | } | |
2425 | ||
2426 | return NOT_CORE_OPTION; | |
2427 | } | |
2428 | ||
2429 | static int set_config_value(struct cache *cache, const char *key, const char *value) | |
2430 | { | |
2431 | int r = process_config_option(cache, key, value); | |
2432 | ||
2433 | if (r == NOT_CORE_OPTION) | |
2434 | r = policy_set_config_value(cache->policy, key, value); | |
2435 | ||
2436 | if (r) | |
2437 | DMWARN("bad config value for %s: %s", key, value); | |
2438 | ||
2439 | return r; | |
2440 | } | |
2441 | ||
2442 | static int set_config_values(struct cache *cache, int argc, const char **argv) | |
2443 | { | |
2444 | int r = 0; | |
2445 | ||
2446 | if (argc & 1) { | |
2447 | DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs."); | |
2448 | return -EINVAL; | |
2449 | } | |
2450 | ||
2451 | while (argc) { | |
2452 | r = set_config_value(cache, argv[0], argv[1]); | |
2453 | if (r) | |
2454 | break; | |
2455 | ||
2456 | argc -= 2; | |
2457 | argv += 2; | |
2458 | } | |
2459 | ||
2460 | return r; | |
2461 | } | |
2462 | ||
2463 | static int create_cache_policy(struct cache *cache, struct cache_args *ca, | |
2464 | char **error) | |
2465 | { | |
2466 | struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name, | |
2467 | cache->cache_size, | |
2468 | cache->origin_sectors, | |
2469 | cache->sectors_per_block); | |
2470 | if (IS_ERR(p)) { | |
2471 | *error = "Error creating cache's policy"; | |
2472 | return PTR_ERR(p); | |
2473 | } | |
2474 | cache->policy = p; | |
2475 | BUG_ON(!cache->policy); | |
2476 | ||
2477 | return 0; | |
2478 | } | |
2479 | ||
2480 | /* | |
2481 | * We want the discard block size to be at least the size of the cache | |
2482 | * block size and have no more than 2^14 discard blocks across the origin. | |
2483 | */ | |
2484 | #define MAX_DISCARD_BLOCKS (1 << 14) | |
2485 | ||
2486 | static bool too_many_discard_blocks(sector_t discard_block_size, | |
2487 | sector_t origin_size) | |
2488 | { | |
2489 | (void) sector_div(origin_size, discard_block_size); | |
2490 | ||
2491 | return origin_size > MAX_DISCARD_BLOCKS; | |
2492 | } | |
2493 | ||
2494 | static sector_t calculate_discard_block_size(sector_t cache_block_size, | |
2495 | sector_t origin_size) | |
2496 | { | |
2497 | sector_t discard_block_size = cache_block_size; | |
2498 | ||
2499 | if (origin_size) | |
2500 | while (too_many_discard_blocks(discard_block_size, origin_size)) | |
2501 | discard_block_size *= 2; | |
2502 | ||
2503 | return discard_block_size; | |
2504 | } | |
2505 | ||
2506 | static void set_cache_size(struct cache *cache, dm_cblock_t size) | |
2507 | { | |
2508 | dm_block_t nr_blocks = from_cblock(size); | |
2509 | ||
2510 | if (nr_blocks > (1 << 20) && cache->cache_size != size) | |
2511 | DMWARN_LIMIT("You have created a cache device with a lot of individual cache blocks (%llu)\n" | |
2512 | "All these mappings can consume a lot of kernel memory, and take some time to read/write.\n" | |
2513 | "Please consider increasing the cache block size to reduce the overall cache block count.", | |
2514 | (unsigned long long) nr_blocks); | |
2515 | ||
2516 | cache->cache_size = size; | |
2517 | } | |
2518 | ||
2519 | static int is_congested(struct dm_dev *dev, int bdi_bits) | |
2520 | { | |
2521 | struct request_queue *q = bdev_get_queue(dev->bdev); | |
2522 | return bdi_congested(q->backing_dev_info, bdi_bits); | |
2523 | } | |
2524 | ||
2525 | static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits) | |
2526 | { | |
2527 | struct cache *cache = container_of(cb, struct cache, callbacks); | |
2528 | ||
2529 | return is_congested(cache->origin_dev, bdi_bits) || | |
2530 | is_congested(cache->cache_dev, bdi_bits); | |
2531 | } | |
2532 | ||
2533 | #define DEFAULT_MIGRATION_THRESHOLD 2048 | |
2534 | ||
2535 | static int cache_create(struct cache_args *ca, struct cache **result) | |
2536 | { | |
2537 | int r = 0; | |
2538 | char **error = &ca->ti->error; | |
2539 | struct cache *cache; | |
2540 | struct dm_target *ti = ca->ti; | |
2541 | dm_block_t origin_blocks; | |
2542 | struct dm_cache_metadata *cmd; | |
2543 | bool may_format = ca->features.mode == CM_WRITE; | |
2544 | ||
2545 | cache = kzalloc(sizeof(*cache), GFP_KERNEL); | |
2546 | if (!cache) | |
2547 | return -ENOMEM; | |
2548 | ||
2549 | cache->ti = ca->ti; | |
2550 | ti->private = cache; | |
2551 | ti->num_flush_bios = 2; | |
2552 | ti->flush_supported = true; | |
2553 | ||
2554 | ti->num_discard_bios = 1; | |
2555 | ti->discards_supported = true; | |
2556 | ti->split_discard_bios = false; | |
2557 | ||
2558 | cache->features = ca->features; | |
2559 | ti->per_io_data_size = get_per_bio_data_size(cache); | |
2560 | ||
2561 | cache->callbacks.congested_fn = cache_is_congested; | |
2562 | dm_table_add_target_callbacks(ti->table, &cache->callbacks); | |
2563 | ||
2564 | cache->metadata_dev = ca->metadata_dev; | |
2565 | cache->origin_dev = ca->origin_dev; | |
2566 | cache->cache_dev = ca->cache_dev; | |
2567 | ||
2568 | ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; | |
2569 | ||
2570 | origin_blocks = cache->origin_sectors = ca->origin_sectors; | |
2571 | origin_blocks = block_div(origin_blocks, ca->block_size); | |
2572 | cache->origin_blocks = to_oblock(origin_blocks); | |
2573 | ||
2574 | cache->sectors_per_block = ca->block_size; | |
2575 | if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) { | |
2576 | r = -EINVAL; | |
2577 | goto bad; | |
2578 | } | |
2579 | ||
2580 | if (ca->block_size & (ca->block_size - 1)) { | |
2581 | dm_block_t cache_size = ca->cache_sectors; | |
2582 | ||
2583 | cache->sectors_per_block_shift = -1; | |
2584 | cache_size = block_div(cache_size, ca->block_size); | |
2585 | set_cache_size(cache, to_cblock(cache_size)); | |
2586 | } else { | |
2587 | cache->sectors_per_block_shift = __ffs(ca->block_size); | |
2588 | set_cache_size(cache, to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift)); | |
2589 | } | |
2590 | ||
2591 | r = create_cache_policy(cache, ca, error); | |
2592 | if (r) | |
2593 | goto bad; | |
2594 | ||
2595 | cache->policy_nr_args = ca->policy_argc; | |
2596 | cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD; | |
2597 | ||
2598 | r = set_config_values(cache, ca->policy_argc, ca->policy_argv); | |
2599 | if (r) { | |
2600 | *error = "Error setting cache policy's config values"; | |
2601 | goto bad; | |
2602 | } | |
2603 | ||
2604 | cmd = dm_cache_metadata_open(cache->metadata_dev->bdev, | |
2605 | ca->block_size, may_format, | |
2606 | dm_cache_policy_get_hint_size(cache->policy), | |
2607 | ca->features.metadata_version); | |
2608 | if (IS_ERR(cmd)) { | |
2609 | *error = "Error creating metadata object"; | |
2610 | r = PTR_ERR(cmd); | |
2611 | goto bad; | |
2612 | } | |
2613 | cache->cmd = cmd; | |
2614 | set_cache_mode(cache, CM_WRITE); | |
2615 | if (get_cache_mode(cache) != CM_WRITE) { | |
2616 | *error = "Unable to get write access to metadata, please check/repair metadata."; | |
2617 | r = -EINVAL; | |
2618 | goto bad; | |
2619 | } | |
2620 | ||
2621 | if (passthrough_mode(&cache->features)) { | |
2622 | bool all_clean; | |
2623 | ||
2624 | r = dm_cache_metadata_all_clean(cache->cmd, &all_clean); | |
2625 | if (r) { | |
2626 | *error = "dm_cache_metadata_all_clean() failed"; | |
2627 | goto bad; | |
2628 | } | |
2629 | ||
2630 | if (!all_clean) { | |
2631 | *error = "Cannot enter passthrough mode unless all blocks are clean"; | |
2632 | r = -EINVAL; | |
2633 | goto bad; | |
2634 | } | |
2635 | ||
2636 | policy_allow_migrations(cache->policy, false); | |
2637 | } | |
2638 | ||
2639 | spin_lock_init(&cache->lock); | |
2640 | INIT_LIST_HEAD(&cache->deferred_cells); | |
2641 | bio_list_init(&cache->deferred_bios); | |
2642 | bio_list_init(&cache->deferred_writethrough_bios); | |
2643 | atomic_set(&cache->nr_allocated_migrations, 0); | |
2644 | atomic_set(&cache->nr_io_migrations, 0); | |
2645 | init_waitqueue_head(&cache->migration_wait); | |
2646 | ||
2647 | r = -ENOMEM; | |
2648 | atomic_set(&cache->nr_dirty, 0); | |
2649 | cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size)); | |
2650 | if (!cache->dirty_bitset) { | |
2651 | *error = "could not allocate dirty bitset"; | |
2652 | goto bad; | |
2653 | } | |
2654 | clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size)); | |
2655 | ||
2656 | cache->discard_block_size = | |
2657 | calculate_discard_block_size(cache->sectors_per_block, | |
2658 | cache->origin_sectors); | |
2659 | cache->discard_nr_blocks = to_dblock(dm_sector_div_up(cache->origin_sectors, | |
2660 | cache->discard_block_size)); | |
2661 | cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks)); | |
2662 | if (!cache->discard_bitset) { | |
2663 | *error = "could not allocate discard bitset"; | |
2664 | goto bad; | |
2665 | } | |
2666 | clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); | |
2667 | ||
2668 | cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); | |
2669 | if (IS_ERR(cache->copier)) { | |
2670 | *error = "could not create kcopyd client"; | |
2671 | r = PTR_ERR(cache->copier); | |
2672 | goto bad; | |
2673 | } | |
2674 | ||
2675 | cache->wq = alloc_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM, 0); | |
2676 | if (!cache->wq) { | |
2677 | *error = "could not create workqueue for metadata object"; | |
2678 | goto bad; | |
2679 | } | |
2680 | INIT_WORK(&cache->deferred_bio_worker, process_deferred_bios); | |
2681 | INIT_WORK(&cache->deferred_writethrough_worker, | |
2682 | process_deferred_writethrough_bios); | |
2683 | INIT_WORK(&cache->migration_worker, check_migrations); | |
2684 | INIT_DELAYED_WORK(&cache->waker, do_waker); | |
2685 | ||
2686 | cache->prison = dm_bio_prison_create_v2(cache->wq); | |
2687 | if (!cache->prison) { | |
2688 | *error = "could not create bio prison"; | |
2689 | goto bad; | |
2690 | } | |
2691 | ||
2692 | cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE, | |
2693 | migration_cache); | |
2694 | if (!cache->migration_pool) { | |
2695 | *error = "Error creating cache's migration mempool"; | |
2696 | goto bad; | |
2697 | } | |
2698 | ||
2699 | cache->need_tick_bio = true; | |
2700 | cache->sized = false; | |
2701 | cache->invalidate = false; | |
2702 | cache->commit_requested = false; | |
2703 | cache->loaded_mappings = false; | |
2704 | cache->loaded_discards = false; | |
2705 | ||
2706 | load_stats(cache); | |
2707 | ||
2708 | atomic_set(&cache->stats.demotion, 0); | |
2709 | atomic_set(&cache->stats.promotion, 0); | |
2710 | atomic_set(&cache->stats.copies_avoided, 0); | |
2711 | atomic_set(&cache->stats.cache_cell_clash, 0); | |
2712 | atomic_set(&cache->stats.commit_count, 0); | |
2713 | atomic_set(&cache->stats.discard_count, 0); | |
2714 | ||
2715 | spin_lock_init(&cache->invalidation_lock); | |
2716 | INIT_LIST_HEAD(&cache->invalidation_requests); | |
2717 | ||
2718 | batcher_init(&cache->committer, commit_op, cache, | |
2719 | issue_op, cache, cache->wq); | |
2720 | iot_init(&cache->tracker); | |
2721 | ||
2722 | init_rwsem(&cache->background_work_lock); | |
2723 | prevent_background_work(cache); | |
2724 | ||
2725 | *result = cache; | |
2726 | return 0; | |
2727 | bad: | |
2728 | destroy(cache); | |
2729 | return r; | |
2730 | } | |
2731 | ||
2732 | static int copy_ctr_args(struct cache *cache, int argc, const char **argv) | |
2733 | { | |
2734 | unsigned i; | |
2735 | const char **copy; | |
2736 | ||
2737 | copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL); | |
2738 | if (!copy) | |
2739 | return -ENOMEM; | |
2740 | for (i = 0; i < argc; i++) { | |
2741 | copy[i] = kstrdup(argv[i], GFP_KERNEL); | |
2742 | if (!copy[i]) { | |
2743 | while (i--) | |
2744 | kfree(copy[i]); | |
2745 | kfree(copy); | |
2746 | return -ENOMEM; | |
2747 | } | |
2748 | } | |
2749 | ||
2750 | cache->nr_ctr_args = argc; | |
2751 | cache->ctr_args = copy; | |
2752 | ||
2753 | return 0; | |
2754 | } | |
2755 | ||
2756 | static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
2757 | { | |
2758 | int r = -EINVAL; | |
2759 | struct cache_args *ca; | |
2760 | struct cache *cache = NULL; | |
2761 | ||
2762 | ca = kzalloc(sizeof(*ca), GFP_KERNEL); | |
2763 | if (!ca) { | |
2764 | ti->error = "Error allocating memory for cache"; | |
2765 | return -ENOMEM; | |
2766 | } | |
2767 | ca->ti = ti; | |
2768 | ||
2769 | r = parse_cache_args(ca, argc, argv, &ti->error); | |
2770 | if (r) | |
2771 | goto out; | |
2772 | ||
2773 | r = cache_create(ca, &cache); | |
2774 | if (r) | |
2775 | goto out; | |
2776 | ||
2777 | r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3); | |
2778 | if (r) { | |
2779 | destroy(cache); | |
2780 | goto out; | |
2781 | } | |
2782 | ||
2783 | ti->private = cache; | |
2784 | out: | |
2785 | destroy_cache_args(ca); | |
2786 | return r; | |
2787 | } | |
2788 | ||
2789 | /*----------------------------------------------------------------*/ | |
2790 | ||
2791 | static int cache_map(struct dm_target *ti, struct bio *bio) | |
2792 | { | |
2793 | struct cache *cache = ti->private; | |
2794 | ||
2795 | int r; | |
2796 | bool commit_needed; | |
2797 | dm_oblock_t block = get_bio_block(cache, bio); | |
2798 | size_t pb_data_size = get_per_bio_data_size(cache); | |
2799 | ||
2800 | init_per_bio_data(bio, pb_data_size); | |
2801 | if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) { | |
2802 | /* | |
2803 | * This can only occur if the io goes to a partial block at | |
2804 | * the end of the origin device. We don't cache these. | |
2805 | * Just remap to the origin and carry on. | |
2806 | */ | |
2807 | remap_to_origin(cache, bio); | |
2808 | accounted_begin(cache, bio); | |
2809 | return DM_MAPIO_REMAPPED; | |
2810 | } | |
2811 | ||
2812 | if (discard_or_flush(bio)) { | |
2813 | defer_bio(cache, bio); | |
2814 | return DM_MAPIO_SUBMITTED; | |
2815 | } | |
2816 | ||
2817 | r = map_bio(cache, bio, block, &commit_needed); | |
2818 | if (commit_needed) | |
2819 | schedule_commit(&cache->committer); | |
2820 | ||
2821 | return r; | |
2822 | } | |
2823 | ||
2824 | static int cache_end_io(struct dm_target *ti, struct bio *bio, | |
2825 | blk_status_t *error) | |
2826 | { | |
2827 | struct cache *cache = ti->private; | |
2828 | unsigned long flags; | |
2829 | size_t pb_data_size = get_per_bio_data_size(cache); | |
2830 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
2831 | ||
2832 | if (pb->tick) { | |
2833 | policy_tick(cache->policy, false); | |
2834 | ||
2835 | spin_lock_irqsave(&cache->lock, flags); | |
2836 | cache->need_tick_bio = true; | |
2837 | spin_unlock_irqrestore(&cache->lock, flags); | |
2838 | } | |
2839 | ||
2840 | bio_drop_shared_lock(cache, bio); | |
2841 | accounted_complete(cache, bio); | |
2842 | ||
2843 | return DM_ENDIO_DONE; | |
2844 | } | |
2845 | ||
2846 | static int write_dirty_bitset(struct cache *cache) | |
2847 | { | |
2848 | int r; | |
2849 | ||
2850 | if (get_cache_mode(cache) >= CM_READ_ONLY) | |
2851 | return -EINVAL; | |
2852 | ||
2853 | r = dm_cache_set_dirty_bits(cache->cmd, from_cblock(cache->cache_size), cache->dirty_bitset); | |
2854 | if (r) | |
2855 | metadata_operation_failed(cache, "dm_cache_set_dirty_bits", r); | |
2856 | ||
2857 | return r; | |
2858 | } | |
2859 | ||
2860 | static int write_discard_bitset(struct cache *cache) | |
2861 | { | |
2862 | unsigned i, r; | |
2863 | ||
2864 | if (get_cache_mode(cache) >= CM_READ_ONLY) | |
2865 | return -EINVAL; | |
2866 | ||
2867 | r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size, | |
2868 | cache->discard_nr_blocks); | |
2869 | if (r) { | |
2870 | DMERR("%s: could not resize on-disk discard bitset", cache_device_name(cache)); | |
2871 | metadata_operation_failed(cache, "dm_cache_discard_bitset_resize", r); | |
2872 | return r; | |
2873 | } | |
2874 | ||
2875 | for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) { | |
2876 | r = dm_cache_set_discard(cache->cmd, to_dblock(i), | |
2877 | is_discarded(cache, to_dblock(i))); | |
2878 | if (r) { | |
2879 | metadata_operation_failed(cache, "dm_cache_set_discard", r); | |
2880 | return r; | |
2881 | } | |
2882 | } | |
2883 | ||
2884 | return 0; | |
2885 | } | |
2886 | ||
2887 | static int write_hints(struct cache *cache) | |
2888 | { | |
2889 | int r; | |
2890 | ||
2891 | if (get_cache_mode(cache) >= CM_READ_ONLY) | |
2892 | return -EINVAL; | |
2893 | ||
2894 | r = dm_cache_write_hints(cache->cmd, cache->policy); | |
2895 | if (r) { | |
2896 | metadata_operation_failed(cache, "dm_cache_write_hints", r); | |
2897 | return r; | |
2898 | } | |
2899 | ||
2900 | return 0; | |
2901 | } | |
2902 | ||
2903 | /* | |
2904 | * returns true on success | |
2905 | */ | |
2906 | static bool sync_metadata(struct cache *cache) | |
2907 | { | |
2908 | int r1, r2, r3, r4; | |
2909 | ||
2910 | r1 = write_dirty_bitset(cache); | |
2911 | if (r1) | |
2912 | DMERR("%s: could not write dirty bitset", cache_device_name(cache)); | |
2913 | ||
2914 | r2 = write_discard_bitset(cache); | |
2915 | if (r2) | |
2916 | DMERR("%s: could not write discard bitset", cache_device_name(cache)); | |
2917 | ||
2918 | save_stats(cache); | |
2919 | ||
2920 | r3 = write_hints(cache); | |
2921 | if (r3) | |
2922 | DMERR("%s: could not write hints", cache_device_name(cache)); | |
2923 | ||
2924 | /* | |
2925 | * If writing the above metadata failed, we still commit, but don't | |
2926 | * set the clean shutdown flag. This will effectively force every | |
2927 | * dirty bit to be set on reload. | |
2928 | */ | |
2929 | r4 = commit(cache, !r1 && !r2 && !r3); | |
2930 | if (r4) | |
2931 | DMERR("%s: could not write cache metadata", cache_device_name(cache)); | |
2932 | ||
2933 | return !r1 && !r2 && !r3 && !r4; | |
2934 | } | |
2935 | ||
2936 | static void cache_postsuspend(struct dm_target *ti) | |
2937 | { | |
2938 | struct cache *cache = ti->private; | |
2939 | ||
2940 | prevent_background_work(cache); | |
2941 | BUG_ON(atomic_read(&cache->nr_io_migrations)); | |
2942 | ||
2943 | cancel_delayed_work(&cache->waker); | |
2944 | flush_workqueue(cache->wq); | |
2945 | WARN_ON(cache->tracker.in_flight); | |
2946 | ||
2947 | /* | |
2948 | * If it's a flush suspend there won't be any deferred bios, so this | |
2949 | * call is harmless. | |
2950 | */ | |
2951 | requeue_deferred_bios(cache); | |
2952 | ||
2953 | if (get_cache_mode(cache) == CM_WRITE) | |
2954 | (void) sync_metadata(cache); | |
2955 | } | |
2956 | ||
2957 | static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, | |
2958 | bool dirty, uint32_t hint, bool hint_valid) | |
2959 | { | |
2960 | int r; | |
2961 | struct cache *cache = context; | |
2962 | ||
2963 | if (dirty) { | |
2964 | set_bit(from_cblock(cblock), cache->dirty_bitset); | |
2965 | atomic_inc(&cache->nr_dirty); | |
2966 | } else | |
2967 | clear_bit(from_cblock(cblock), cache->dirty_bitset); | |
2968 | ||
2969 | r = policy_load_mapping(cache->policy, oblock, cblock, dirty, hint, hint_valid); | |
2970 | if (r) | |
2971 | return r; | |
2972 | ||
2973 | return 0; | |
2974 | } | |
2975 | ||
2976 | /* | |
2977 | * The discard block size in the on disk metadata is not | |
2978 | * neccessarily the same as we're currently using. So we have to | |
2979 | * be careful to only set the discarded attribute if we know it | |
2980 | * covers a complete block of the new size. | |
2981 | */ | |
2982 | struct discard_load_info { | |
2983 | struct cache *cache; | |
2984 | ||
2985 | /* | |
2986 | * These blocks are sized using the on disk dblock size, rather | |
2987 | * than the current one. | |
2988 | */ | |
2989 | dm_block_t block_size; | |
2990 | dm_block_t discard_begin, discard_end; | |
2991 | }; | |
2992 | ||
2993 | static void discard_load_info_init(struct cache *cache, | |
2994 | struct discard_load_info *li) | |
2995 | { | |
2996 | li->cache = cache; | |
2997 | li->discard_begin = li->discard_end = 0; | |
2998 | } | |
2999 | ||
3000 | static void set_discard_range(struct discard_load_info *li) | |
3001 | { | |
3002 | sector_t b, e; | |
3003 | ||
3004 | if (li->discard_begin == li->discard_end) | |
3005 | return; | |
3006 | ||
3007 | /* | |
3008 | * Convert to sectors. | |
3009 | */ | |
3010 | b = li->discard_begin * li->block_size; | |
3011 | e = li->discard_end * li->block_size; | |
3012 | ||
3013 | /* | |
3014 | * Then convert back to the current dblock size. | |
3015 | */ | |
3016 | b = dm_sector_div_up(b, li->cache->discard_block_size); | |
3017 | sector_div(e, li->cache->discard_block_size); | |
3018 | ||
3019 | /* | |
3020 | * The origin may have shrunk, so we need to check we're still in | |
3021 | * bounds. | |
3022 | */ | |
3023 | if (e > from_dblock(li->cache->discard_nr_blocks)) | |
3024 | e = from_dblock(li->cache->discard_nr_blocks); | |
3025 | ||
3026 | for (; b < e; b++) | |
3027 | set_discard(li->cache, to_dblock(b)); | |
3028 | } | |
3029 | ||
3030 | static int load_discard(void *context, sector_t discard_block_size, | |
3031 | dm_dblock_t dblock, bool discard) | |
3032 | { | |
3033 | struct discard_load_info *li = context; | |
3034 | ||
3035 | li->block_size = discard_block_size; | |
3036 | ||
3037 | if (discard) { | |
3038 | if (from_dblock(dblock) == li->discard_end) | |
3039 | /* | |
3040 | * We're already in a discard range, just extend it. | |
3041 | */ | |
3042 | li->discard_end = li->discard_end + 1ULL; | |
3043 | ||
3044 | else { | |
3045 | /* | |
3046 | * Emit the old range and start a new one. | |
3047 | */ | |
3048 | set_discard_range(li); | |
3049 | li->discard_begin = from_dblock(dblock); | |
3050 | li->discard_end = li->discard_begin + 1ULL; | |
3051 | } | |
3052 | } else { | |
3053 | set_discard_range(li); | |
3054 | li->discard_begin = li->discard_end = 0; | |
3055 | } | |
3056 | ||
3057 | return 0; | |
3058 | } | |
3059 | ||
3060 | static dm_cblock_t get_cache_dev_size(struct cache *cache) | |
3061 | { | |
3062 | sector_t size = get_dev_size(cache->cache_dev); | |
3063 | (void) sector_div(size, cache->sectors_per_block); | |
3064 | return to_cblock(size); | |
3065 | } | |
3066 | ||
3067 | static bool can_resize(struct cache *cache, dm_cblock_t new_size) | |
3068 | { | |
3069 | if (from_cblock(new_size) > from_cblock(cache->cache_size)) | |
3070 | return true; | |
3071 | ||
3072 | /* | |
3073 | * We can't drop a dirty block when shrinking the cache. | |
3074 | */ | |
3075 | while (from_cblock(new_size) < from_cblock(cache->cache_size)) { | |
3076 | new_size = to_cblock(from_cblock(new_size) + 1); | |
3077 | if (is_dirty(cache, new_size)) { | |
3078 | DMERR("%s: unable to shrink cache; cache block %llu is dirty", | |
3079 | cache_device_name(cache), | |
3080 | (unsigned long long) from_cblock(new_size)); | |
3081 | return false; | |
3082 | } | |
3083 | } | |
3084 | ||
3085 | return true; | |
3086 | } | |
3087 | ||
3088 | static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size) | |
3089 | { | |
3090 | int r; | |
3091 | ||
3092 | r = dm_cache_resize(cache->cmd, new_size); | |
3093 | if (r) { | |
3094 | DMERR("%s: could not resize cache metadata", cache_device_name(cache)); | |
3095 | metadata_operation_failed(cache, "dm_cache_resize", r); | |
3096 | return r; | |
3097 | } | |
3098 | ||
3099 | set_cache_size(cache, new_size); | |
3100 | ||
3101 | return 0; | |
3102 | } | |
3103 | ||
3104 | static int cache_preresume(struct dm_target *ti) | |
3105 | { | |
3106 | int r = 0; | |
3107 | struct cache *cache = ti->private; | |
3108 | dm_cblock_t csize = get_cache_dev_size(cache); | |
3109 | ||
3110 | /* | |
3111 | * Check to see if the cache has resized. | |
3112 | */ | |
3113 | if (!cache->sized) { | |
3114 | r = resize_cache_dev(cache, csize); | |
3115 | if (r) | |
3116 | return r; | |
3117 | ||
3118 | cache->sized = true; | |
3119 | ||
3120 | } else if (csize != cache->cache_size) { | |
3121 | if (!can_resize(cache, csize)) | |
3122 | return -EINVAL; | |
3123 | ||
3124 | r = resize_cache_dev(cache, csize); | |
3125 | if (r) | |
3126 | return r; | |
3127 | } | |
3128 | ||
3129 | if (!cache->loaded_mappings) { | |
3130 | r = dm_cache_load_mappings(cache->cmd, cache->policy, | |
3131 | load_mapping, cache); | |
3132 | if (r) { | |
3133 | DMERR("%s: could not load cache mappings", cache_device_name(cache)); | |
3134 | metadata_operation_failed(cache, "dm_cache_load_mappings", r); | |
3135 | return r; | |
3136 | } | |
3137 | ||
3138 | cache->loaded_mappings = true; | |
3139 | } | |
3140 | ||
3141 | if (!cache->loaded_discards) { | |
3142 | struct discard_load_info li; | |
3143 | ||
3144 | /* | |
3145 | * The discard bitset could have been resized, or the | |
3146 | * discard block size changed. To be safe we start by | |
3147 | * setting every dblock to not discarded. | |
3148 | */ | |
3149 | clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); | |
3150 | ||
3151 | discard_load_info_init(cache, &li); | |
3152 | r = dm_cache_load_discards(cache->cmd, load_discard, &li); | |
3153 | if (r) { | |
3154 | DMERR("%s: could not load origin discards", cache_device_name(cache)); | |
3155 | metadata_operation_failed(cache, "dm_cache_load_discards", r); | |
3156 | return r; | |
3157 | } | |
3158 | set_discard_range(&li); | |
3159 | ||
3160 | cache->loaded_discards = true; | |
3161 | } | |
3162 | ||
3163 | return r; | |
3164 | } | |
3165 | ||
3166 | static void cache_resume(struct dm_target *ti) | |
3167 | { | |
3168 | struct cache *cache = ti->private; | |
3169 | ||
3170 | cache->need_tick_bio = true; | |
3171 | allow_background_work(cache); | |
3172 | do_waker(&cache->waker.work); | |
3173 | } | |
3174 | ||
3175 | /* | |
3176 | * Status format: | |
3177 | * | |
3178 | * <metadata block size> <#used metadata blocks>/<#total metadata blocks> | |
3179 | * <cache block size> <#used cache blocks>/<#total cache blocks> | |
3180 | * <#read hits> <#read misses> <#write hits> <#write misses> | |
3181 | * <#demotions> <#promotions> <#dirty> | |
3182 | * <#features> <features>* | |
3183 | * <#core args> <core args> | |
3184 | * <policy name> <#policy args> <policy args>* <cache metadata mode> <needs_check> | |
3185 | */ | |
3186 | static void cache_status(struct dm_target *ti, status_type_t type, | |
3187 | unsigned status_flags, char *result, unsigned maxlen) | |
3188 | { | |
3189 | int r = 0; | |
3190 | unsigned i; | |
3191 | ssize_t sz = 0; | |
3192 | dm_block_t nr_free_blocks_metadata = 0; | |
3193 | dm_block_t nr_blocks_metadata = 0; | |
3194 | char buf[BDEVNAME_SIZE]; | |
3195 | struct cache *cache = ti->private; | |
3196 | dm_cblock_t residency; | |
3197 | bool needs_check; | |
3198 | ||
3199 | switch (type) { | |
3200 | case STATUSTYPE_INFO: | |
3201 | if (get_cache_mode(cache) == CM_FAIL) { | |
3202 | DMEMIT("Fail"); | |
3203 | break; | |
3204 | } | |
3205 | ||
3206 | /* Commit to ensure statistics aren't out-of-date */ | |
3207 | if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) | |
3208 | (void) commit(cache, false); | |
3209 | ||
3210 | r = dm_cache_get_free_metadata_block_count(cache->cmd, &nr_free_blocks_metadata); | |
3211 | if (r) { | |
3212 | DMERR("%s: dm_cache_get_free_metadata_block_count returned %d", | |
3213 | cache_device_name(cache), r); | |
3214 | goto err; | |
3215 | } | |
3216 | ||
3217 | r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata); | |
3218 | if (r) { | |
3219 | DMERR("%s: dm_cache_get_metadata_dev_size returned %d", | |
3220 | cache_device_name(cache), r); | |
3221 | goto err; | |
3222 | } | |
3223 | ||
3224 | residency = policy_residency(cache->policy); | |
3225 | ||
3226 | DMEMIT("%u %llu/%llu %llu %llu/%llu %u %u %u %u %u %u %lu ", | |
3227 | (unsigned)DM_CACHE_METADATA_BLOCK_SIZE, | |
3228 | (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), | |
3229 | (unsigned long long)nr_blocks_metadata, | |
3230 | (unsigned long long)cache->sectors_per_block, | |
3231 | (unsigned long long) from_cblock(residency), | |
3232 | (unsigned long long) from_cblock(cache->cache_size), | |
3233 | (unsigned) atomic_read(&cache->stats.read_hit), | |
3234 | (unsigned) atomic_read(&cache->stats.read_miss), | |
3235 | (unsigned) atomic_read(&cache->stats.write_hit), | |
3236 | (unsigned) atomic_read(&cache->stats.write_miss), | |
3237 | (unsigned) atomic_read(&cache->stats.demotion), | |
3238 | (unsigned) atomic_read(&cache->stats.promotion), | |
3239 | (unsigned long) atomic_read(&cache->nr_dirty)); | |
3240 | ||
3241 | if (cache->features.metadata_version == 2) | |
3242 | DMEMIT("2 metadata2 "); | |
3243 | else | |
3244 | DMEMIT("1 "); | |
3245 | ||
3246 | if (writethrough_mode(&cache->features)) | |
3247 | DMEMIT("writethrough "); | |
3248 | ||
3249 | else if (passthrough_mode(&cache->features)) | |
3250 | DMEMIT("passthrough "); | |
3251 | ||
3252 | else if (writeback_mode(&cache->features)) | |
3253 | DMEMIT("writeback "); | |
3254 | ||
3255 | else { | |
3256 | DMERR("%s: internal error: unknown io mode: %d", | |
3257 | cache_device_name(cache), (int) cache->features.io_mode); | |
3258 | goto err; | |
3259 | } | |
3260 | ||
3261 | DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold); | |
3262 | ||
3263 | DMEMIT("%s ", dm_cache_policy_get_name(cache->policy)); | |
3264 | if (sz < maxlen) { | |
3265 | r = policy_emit_config_values(cache->policy, result, maxlen, &sz); | |
3266 | if (r) | |
3267 | DMERR("%s: policy_emit_config_values returned %d", | |
3268 | cache_device_name(cache), r); | |
3269 | } | |
3270 | ||
3271 | if (get_cache_mode(cache) == CM_READ_ONLY) | |
3272 | DMEMIT("ro "); | |
3273 | else | |
3274 | DMEMIT("rw "); | |
3275 | ||
3276 | r = dm_cache_metadata_needs_check(cache->cmd, &needs_check); | |
3277 | ||
3278 | if (r || needs_check) | |
3279 | DMEMIT("needs_check "); | |
3280 | else | |
3281 | DMEMIT("- "); | |
3282 | ||
3283 | break; | |
3284 | ||
3285 | case STATUSTYPE_TABLE: | |
3286 | format_dev_t(buf, cache->metadata_dev->bdev->bd_dev); | |
3287 | DMEMIT("%s ", buf); | |
3288 | format_dev_t(buf, cache->cache_dev->bdev->bd_dev); | |
3289 | DMEMIT("%s ", buf); | |
3290 | format_dev_t(buf, cache->origin_dev->bdev->bd_dev); | |
3291 | DMEMIT("%s", buf); | |
3292 | ||
3293 | for (i = 0; i < cache->nr_ctr_args - 1; i++) | |
3294 | DMEMIT(" %s", cache->ctr_args[i]); | |
3295 | if (cache->nr_ctr_args) | |
3296 | DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]); | |
3297 | } | |
3298 | ||
3299 | return; | |
3300 | ||
3301 | err: | |
3302 | DMEMIT("Error"); | |
3303 | } | |
3304 | ||
3305 | /* | |
3306 | * Defines a range of cblocks, begin to (end - 1) are in the range. end is | |
3307 | * the one-past-the-end value. | |
3308 | */ | |
3309 | struct cblock_range { | |
3310 | dm_cblock_t begin; | |
3311 | dm_cblock_t end; | |
3312 | }; | |
3313 | ||
3314 | /* | |
3315 | * A cache block range can take two forms: | |
3316 | * | |
3317 | * i) A single cblock, eg. '3456' | |
3318 | * ii) A begin and end cblock with a dash between, eg. 123-234 | |
3319 | */ | |
3320 | static int parse_cblock_range(struct cache *cache, const char *str, | |
3321 | struct cblock_range *result) | |
3322 | { | |
3323 | char dummy; | |
3324 | uint64_t b, e; | |
3325 | int r; | |
3326 | ||
3327 | /* | |
3328 | * Try and parse form (ii) first. | |
3329 | */ | |
3330 | r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); | |
3331 | if (r < 0) | |
3332 | return r; | |
3333 | ||
3334 | if (r == 2) { | |
3335 | result->begin = to_cblock(b); | |
3336 | result->end = to_cblock(e); | |
3337 | return 0; | |
3338 | } | |
3339 | ||
3340 | /* | |
3341 | * That didn't work, try form (i). | |
3342 | */ | |
3343 | r = sscanf(str, "%llu%c", &b, &dummy); | |
3344 | if (r < 0) | |
3345 | return r; | |
3346 | ||
3347 | if (r == 1) { | |
3348 | result->begin = to_cblock(b); | |
3349 | result->end = to_cblock(from_cblock(result->begin) + 1u); | |
3350 | return 0; | |
3351 | } | |
3352 | ||
3353 | DMERR("%s: invalid cblock range '%s'", cache_device_name(cache), str); | |
3354 | return -EINVAL; | |
3355 | } | |
3356 | ||
3357 | static int validate_cblock_range(struct cache *cache, struct cblock_range *range) | |
3358 | { | |
3359 | uint64_t b = from_cblock(range->begin); | |
3360 | uint64_t e = from_cblock(range->end); | |
3361 | uint64_t n = from_cblock(cache->cache_size); | |
3362 | ||
3363 | if (b >= n) { | |
3364 | DMERR("%s: begin cblock out of range: %llu >= %llu", | |
3365 | cache_device_name(cache), b, n); | |
3366 | return -EINVAL; | |
3367 | } | |
3368 | ||
3369 | if (e > n) { | |
3370 | DMERR("%s: end cblock out of range: %llu > %llu", | |
3371 | cache_device_name(cache), e, n); | |
3372 | return -EINVAL; | |
3373 | } | |
3374 | ||
3375 | if (b >= e) { | |
3376 | DMERR("%s: invalid cblock range: %llu >= %llu", | |
3377 | cache_device_name(cache), b, e); | |
3378 | return -EINVAL; | |
3379 | } | |
3380 | ||
3381 | return 0; | |
3382 | } | |
3383 | ||
3384 | static inline dm_cblock_t cblock_succ(dm_cblock_t b) | |
3385 | { | |
3386 | return to_cblock(from_cblock(b) + 1); | |
3387 | } | |
3388 | ||
3389 | static int request_invalidation(struct cache *cache, struct cblock_range *range) | |
3390 | { | |
3391 | int r = 0; | |
3392 | ||
3393 | /* | |
3394 | * We don't need to do any locking here because we know we're in | |
3395 | * passthrough mode. There's is potential for a race between an | |
3396 | * invalidation triggered by an io and an invalidation message. This | |
3397 | * is harmless, we must not worry if the policy call fails. | |
3398 | */ | |
3399 | while (range->begin != range->end) { | |
3400 | r = invalidate_cblock(cache, range->begin); | |
3401 | if (r) | |
3402 | return r; | |
3403 | ||
3404 | range->begin = cblock_succ(range->begin); | |
3405 | } | |
3406 | ||
3407 | cache->commit_requested = true; | |
3408 | return r; | |
3409 | } | |
3410 | ||
3411 | static int process_invalidate_cblocks_message(struct cache *cache, unsigned count, | |
3412 | const char **cblock_ranges) | |
3413 | { | |
3414 | int r = 0; | |
3415 | unsigned i; | |
3416 | struct cblock_range range; | |
3417 | ||
3418 | if (!passthrough_mode(&cache->features)) { | |
3419 | DMERR("%s: cache has to be in passthrough mode for invalidation", | |
3420 | cache_device_name(cache)); | |
3421 | return -EPERM; | |
3422 | } | |
3423 | ||
3424 | for (i = 0; i < count; i++) { | |
3425 | r = parse_cblock_range(cache, cblock_ranges[i], &range); | |
3426 | if (r) | |
3427 | break; | |
3428 | ||
3429 | r = validate_cblock_range(cache, &range); | |
3430 | if (r) | |
3431 | break; | |
3432 | ||
3433 | /* | |
3434 | * Pass begin and end origin blocks to the worker and wake it. | |
3435 | */ | |
3436 | r = request_invalidation(cache, &range); | |
3437 | if (r) | |
3438 | break; | |
3439 | } | |
3440 | ||
3441 | return r; | |
3442 | } | |
3443 | ||
3444 | /* | |
3445 | * Supports | |
3446 | * "<key> <value>" | |
3447 | * and | |
3448 | * "invalidate_cblocks [(<begin>)|(<begin>-<end>)]* | |
3449 | * | |
3450 | * The key migration_threshold is supported by the cache target core. | |
3451 | */ | |
3452 | static int cache_message(struct dm_target *ti, unsigned argc, char **argv) | |
3453 | { | |
3454 | struct cache *cache = ti->private; | |
3455 | ||
3456 | if (!argc) | |
3457 | return -EINVAL; | |
3458 | ||
3459 | if (get_cache_mode(cache) >= CM_READ_ONLY) { | |
3460 | DMERR("%s: unable to service cache target messages in READ_ONLY or FAIL mode", | |
3461 | cache_device_name(cache)); | |
3462 | return -EOPNOTSUPP; | |
3463 | } | |
3464 | ||
3465 | if (!strcasecmp(argv[0], "invalidate_cblocks")) | |
3466 | return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1); | |
3467 | ||
3468 | if (argc != 2) | |
3469 | return -EINVAL; | |
3470 | ||
3471 | return set_config_value(cache, argv[0], argv[1]); | |
3472 | } | |
3473 | ||
3474 | static int cache_iterate_devices(struct dm_target *ti, | |
3475 | iterate_devices_callout_fn fn, void *data) | |
3476 | { | |
3477 | int r = 0; | |
3478 | struct cache *cache = ti->private; | |
3479 | ||
3480 | r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data); | |
3481 | if (!r) | |
3482 | r = fn(ti, cache->origin_dev, 0, ti->len, data); | |
3483 | ||
3484 | return r; | |
3485 | } | |
3486 | ||
3487 | static void set_discard_limits(struct cache *cache, struct queue_limits *limits) | |
3488 | { | |
3489 | /* | |
3490 | * FIXME: these limits may be incompatible with the cache device | |
3491 | */ | |
3492 | limits->max_discard_sectors = min_t(sector_t, cache->discard_block_size * 1024, | |
3493 | cache->origin_sectors); | |
3494 | limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT; | |
3495 | } | |
3496 | ||
3497 | static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
3498 | { | |
3499 | struct cache *cache = ti->private; | |
3500 | uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; | |
3501 | ||
3502 | /* | |
3503 | * If the system-determined stacked limits are compatible with the | |
3504 | * cache's blocksize (io_opt is a factor) do not override them. | |
3505 | */ | |
3506 | if (io_opt_sectors < cache->sectors_per_block || | |
3507 | do_div(io_opt_sectors, cache->sectors_per_block)) { | |
3508 | blk_limits_io_min(limits, cache->sectors_per_block << SECTOR_SHIFT); | |
3509 | blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT); | |
3510 | } | |
3511 | set_discard_limits(cache, limits); | |
3512 | } | |
3513 | ||
3514 | /*----------------------------------------------------------------*/ | |
3515 | ||
3516 | static struct target_type cache_target = { | |
3517 | .name = "cache", | |
3518 | .version = {2, 0, 0}, | |
3519 | .module = THIS_MODULE, | |
3520 | .ctr = cache_ctr, | |
3521 | .dtr = cache_dtr, | |
3522 | .map = cache_map, | |
3523 | .end_io = cache_end_io, | |
3524 | .postsuspend = cache_postsuspend, | |
3525 | .preresume = cache_preresume, | |
3526 | .resume = cache_resume, | |
3527 | .status = cache_status, | |
3528 | .message = cache_message, | |
3529 | .iterate_devices = cache_iterate_devices, | |
3530 | .io_hints = cache_io_hints, | |
3531 | }; | |
3532 | ||
3533 | static int __init dm_cache_init(void) | |
3534 | { | |
3535 | int r; | |
3536 | ||
3537 | r = dm_register_target(&cache_target); | |
3538 | if (r) { | |
3539 | DMERR("cache target registration failed: %d", r); | |
3540 | return r; | |
3541 | } | |
3542 | ||
3543 | migration_cache = KMEM_CACHE(dm_cache_migration, 0); | |
3544 | if (!migration_cache) { | |
3545 | dm_unregister_target(&cache_target); | |
3546 | return -ENOMEM; | |
3547 | } | |
3548 | ||
3549 | return 0; | |
3550 | } | |
3551 | ||
3552 | static void __exit dm_cache_exit(void) | |
3553 | { | |
3554 | dm_unregister_target(&cache_target); | |
3555 | kmem_cache_destroy(migration_cache); | |
3556 | } | |
3557 | ||
3558 | module_init(dm_cache_init); | |
3559 | module_exit(dm_cache_exit); | |
3560 | ||
3561 | MODULE_DESCRIPTION(DM_NAME " cache target"); | |
3562 | MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); | |
3563 | MODULE_LICENSE("GPL"); |