Commit | Line | Data |
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c6b4fcba JT |
1 | /* |
2 | * Copyright (C) 2012 Red Hat. All rights reserved. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
7 | #include "dm.h" | |
8 | #include "dm-bio-prison.h" | |
b844fe69 | 9 | #include "dm-bio-record.h" |
c6b4fcba JT |
10 | #include "dm-cache-metadata.h" |
11 | ||
12 | #include <linux/dm-io.h> | |
13 | #include <linux/dm-kcopyd.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/mempool.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/slab.h> | |
18 | #include <linux/vmalloc.h> | |
19 | ||
20 | #define DM_MSG_PREFIX "cache" | |
21 | ||
22 | DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle, | |
23 | "A percentage of time allocated for copying to and/or from cache"); | |
24 | ||
25 | /*----------------------------------------------------------------*/ | |
26 | ||
27 | /* | |
28 | * Glossary: | |
29 | * | |
30 | * oblock: index of an origin block | |
31 | * cblock: index of a cache block | |
32 | * promotion: movement of a block from origin to cache | |
33 | * demotion: movement of a block from cache to origin | |
34 | * migration: movement of a block between the origin and cache device, | |
35 | * either direction | |
36 | */ | |
37 | ||
38 | /*----------------------------------------------------------------*/ | |
39 | ||
40 | static size_t bitset_size_in_bytes(unsigned nr_entries) | |
41 | { | |
42 | return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG); | |
43 | } | |
44 | ||
45 | static unsigned long *alloc_bitset(unsigned nr_entries) | |
46 | { | |
47 | size_t s = bitset_size_in_bytes(nr_entries); | |
48 | return vzalloc(s); | |
49 | } | |
50 | ||
51 | static void clear_bitset(void *bitset, unsigned nr_entries) | |
52 | { | |
53 | size_t s = bitset_size_in_bytes(nr_entries); | |
54 | memset(bitset, 0, s); | |
55 | } | |
56 | ||
57 | static void free_bitset(unsigned long *bits) | |
58 | { | |
59 | vfree(bits); | |
60 | } | |
61 | ||
62 | /*----------------------------------------------------------------*/ | |
63 | ||
c9d28d5d JT |
64 | /* |
65 | * There are a couple of places where we let a bio run, but want to do some | |
66 | * work before calling its endio function. We do this by temporarily | |
67 | * changing the endio fn. | |
68 | */ | |
69 | struct dm_hook_info { | |
70 | bio_end_io_t *bi_end_io; | |
71 | void *bi_private; | |
72 | }; | |
73 | ||
74 | static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio, | |
75 | bio_end_io_t *bi_end_io, void *bi_private) | |
76 | { | |
77 | h->bi_end_io = bio->bi_end_io; | |
78 | h->bi_private = bio->bi_private; | |
79 | ||
80 | bio->bi_end_io = bi_end_io; | |
81 | bio->bi_private = bi_private; | |
82 | } | |
83 | ||
84 | static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio) | |
85 | { | |
86 | bio->bi_end_io = h->bi_end_io; | |
87 | bio->bi_private = h->bi_private; | |
88 | } | |
89 | ||
90 | /*----------------------------------------------------------------*/ | |
91 | ||
c6b4fcba JT |
92 | #define PRISON_CELLS 1024 |
93 | #define MIGRATION_POOL_SIZE 128 | |
94 | #define COMMIT_PERIOD HZ | |
95 | #define MIGRATION_COUNT_WINDOW 10 | |
96 | ||
97 | /* | |
05473044 MS |
98 | * The block size of the device holding cache data must be |
99 | * between 32KB and 1GB. | |
c6b4fcba JT |
100 | */ |
101 | #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) | |
05473044 | 102 | #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) |
c6b4fcba JT |
103 | |
104 | /* | |
105 | * FIXME: the cache is read/write for the time being. | |
106 | */ | |
2ee57d58 | 107 | enum cache_metadata_mode { |
c6b4fcba JT |
108 | CM_WRITE, /* metadata may be changed */ |
109 | CM_READ_ONLY, /* metadata may not be changed */ | |
110 | }; | |
111 | ||
2ee57d58 JT |
112 | enum cache_io_mode { |
113 | /* | |
114 | * Data is written to cached blocks only. These blocks are marked | |
115 | * dirty. If you lose the cache device you will lose data. | |
116 | * Potential performance increase for both reads and writes. | |
117 | */ | |
118 | CM_IO_WRITEBACK, | |
119 | ||
120 | /* | |
121 | * Data is written to both cache and origin. Blocks are never | |
122 | * dirty. Potential performance benfit for reads only. | |
123 | */ | |
124 | CM_IO_WRITETHROUGH, | |
125 | ||
126 | /* | |
127 | * A degraded mode useful for various cache coherency situations | |
128 | * (eg, rolling back snapshots). Reads and writes always go to the | |
129 | * origin. If a write goes to a cached oblock, then the cache | |
130 | * block is invalidated. | |
131 | */ | |
132 | CM_IO_PASSTHROUGH | |
133 | }; | |
134 | ||
c6b4fcba | 135 | struct cache_features { |
2ee57d58 JT |
136 | enum cache_metadata_mode mode; |
137 | enum cache_io_mode io_mode; | |
c6b4fcba JT |
138 | }; |
139 | ||
140 | struct cache_stats { | |
141 | atomic_t read_hit; | |
142 | atomic_t read_miss; | |
143 | atomic_t write_hit; | |
144 | atomic_t write_miss; | |
145 | atomic_t demotion; | |
146 | atomic_t promotion; | |
147 | atomic_t copies_avoided; | |
148 | atomic_t cache_cell_clash; | |
149 | atomic_t commit_count; | |
150 | atomic_t discard_count; | |
151 | }; | |
152 | ||
153 | struct cache { | |
154 | struct dm_target *ti; | |
155 | struct dm_target_callbacks callbacks; | |
156 | ||
c9ec5d7c MS |
157 | struct dm_cache_metadata *cmd; |
158 | ||
c6b4fcba JT |
159 | /* |
160 | * Metadata is written to this device. | |
161 | */ | |
162 | struct dm_dev *metadata_dev; | |
163 | ||
164 | /* | |
165 | * The slower of the two data devices. Typically a spindle. | |
166 | */ | |
167 | struct dm_dev *origin_dev; | |
168 | ||
169 | /* | |
170 | * The faster of the two data devices. Typically an SSD. | |
171 | */ | |
172 | struct dm_dev *cache_dev; | |
173 | ||
c6b4fcba JT |
174 | /* |
175 | * Size of the origin device in _complete_ blocks and native sectors. | |
176 | */ | |
177 | dm_oblock_t origin_blocks; | |
178 | sector_t origin_sectors; | |
179 | ||
180 | /* | |
181 | * Size of the cache device in blocks. | |
182 | */ | |
183 | dm_cblock_t cache_size; | |
184 | ||
185 | /* | |
186 | * Fields for converting from sectors to blocks. | |
187 | */ | |
188 | uint32_t sectors_per_block; | |
189 | int sectors_per_block_shift; | |
190 | ||
c6b4fcba JT |
191 | spinlock_t lock; |
192 | struct bio_list deferred_bios; | |
193 | struct bio_list deferred_flush_bios; | |
e2e74d61 | 194 | struct bio_list deferred_writethrough_bios; |
c6b4fcba JT |
195 | struct list_head quiesced_migrations; |
196 | struct list_head completed_migrations; | |
197 | struct list_head need_commit_migrations; | |
198 | sector_t migration_threshold; | |
c6b4fcba | 199 | wait_queue_head_t migration_wait; |
c9ec5d7c | 200 | atomic_t nr_migrations; |
c6b4fcba | 201 | |
66cb1910 | 202 | wait_queue_head_t quiescing_wait; |
238f8363 | 203 | atomic_t quiescing; |
66cb1910 JT |
204 | atomic_t quiescing_ack; |
205 | ||
c6b4fcba JT |
206 | /* |
207 | * cache_size entries, dirty if set | |
208 | */ | |
209 | dm_cblock_t nr_dirty; | |
210 | unsigned long *dirty_bitset; | |
211 | ||
212 | /* | |
213 | * origin_blocks entries, discarded if set. | |
214 | */ | |
c6b4fcba JT |
215 | dm_dblock_t discard_nr_blocks; |
216 | unsigned long *discard_bitset; | |
c9ec5d7c MS |
217 | uint32_t discard_block_size; /* a power of 2 times sectors per block */ |
218 | ||
219 | /* | |
220 | * Rather than reconstructing the table line for the status we just | |
221 | * save it and regurgitate. | |
222 | */ | |
223 | unsigned nr_ctr_args; | |
224 | const char **ctr_args; | |
c6b4fcba JT |
225 | |
226 | struct dm_kcopyd_client *copier; | |
227 | struct workqueue_struct *wq; | |
228 | struct work_struct worker; | |
229 | ||
230 | struct delayed_work waker; | |
231 | unsigned long last_commit_jiffies; | |
232 | ||
233 | struct dm_bio_prison *prison; | |
234 | struct dm_deferred_set *all_io_ds; | |
235 | ||
236 | mempool_t *migration_pool; | |
237 | struct dm_cache_migration *next_migration; | |
238 | ||
239 | struct dm_cache_policy *policy; | |
240 | unsigned policy_nr_args; | |
241 | ||
242 | bool need_tick_bio:1; | |
243 | bool sized:1; | |
c6b4fcba JT |
244 | bool commit_requested:1; |
245 | bool loaded_mappings:1; | |
246 | bool loaded_discards:1; | |
247 | ||
c6b4fcba | 248 | /* |
c9ec5d7c | 249 | * Cache features such as write-through. |
c6b4fcba | 250 | */ |
c9ec5d7c MS |
251 | struct cache_features features; |
252 | ||
253 | struct cache_stats stats; | |
c6b4fcba JT |
254 | }; |
255 | ||
256 | struct per_bio_data { | |
257 | bool tick:1; | |
258 | unsigned req_nr:2; | |
259 | struct dm_deferred_entry *all_io_entry; | |
e2e74d61 | 260 | |
19b0092e MS |
261 | /* |
262 | * writethrough fields. These MUST remain at the end of this | |
263 | * structure and the 'cache' member must be the first as it | |
aeed1420 | 264 | * is used to determine the offset of the writethrough fields. |
19b0092e | 265 | */ |
e2e74d61 JT |
266 | struct cache *cache; |
267 | dm_cblock_t cblock; | |
c9d28d5d | 268 | struct dm_hook_info hook_info; |
b844fe69 | 269 | struct dm_bio_details bio_details; |
c6b4fcba JT |
270 | }; |
271 | ||
272 | struct dm_cache_migration { | |
273 | struct list_head list; | |
274 | struct cache *cache; | |
275 | ||
276 | unsigned long start_jiffies; | |
277 | dm_oblock_t old_oblock; | |
278 | dm_oblock_t new_oblock; | |
279 | dm_cblock_t cblock; | |
280 | ||
281 | bool err:1; | |
282 | bool writeback:1; | |
283 | bool demote:1; | |
284 | bool promote:1; | |
c9d28d5d | 285 | bool requeue_holder:1; |
c6b4fcba JT |
286 | |
287 | struct dm_bio_prison_cell *old_ocell; | |
288 | struct dm_bio_prison_cell *new_ocell; | |
289 | }; | |
290 | ||
291 | /* | |
292 | * Processing a bio in the worker thread may require these memory | |
293 | * allocations. We prealloc to avoid deadlocks (the same worker thread | |
294 | * frees them back to the mempool). | |
295 | */ | |
296 | struct prealloc { | |
297 | struct dm_cache_migration *mg; | |
298 | struct dm_bio_prison_cell *cell1; | |
299 | struct dm_bio_prison_cell *cell2; | |
300 | }; | |
301 | ||
302 | static void wake_worker(struct cache *cache) | |
303 | { | |
304 | queue_work(cache->wq, &cache->worker); | |
305 | } | |
306 | ||
307 | /*----------------------------------------------------------------*/ | |
308 | ||
309 | static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache) | |
310 | { | |
311 | /* FIXME: change to use a local slab. */ | |
312 | return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT); | |
313 | } | |
314 | ||
315 | static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell) | |
316 | { | |
317 | dm_bio_prison_free_cell(cache->prison, cell); | |
318 | } | |
319 | ||
320 | static int prealloc_data_structs(struct cache *cache, struct prealloc *p) | |
321 | { | |
322 | if (!p->mg) { | |
323 | p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT); | |
324 | if (!p->mg) | |
325 | return -ENOMEM; | |
326 | } | |
327 | ||
328 | if (!p->cell1) { | |
329 | p->cell1 = alloc_prison_cell(cache); | |
330 | if (!p->cell1) | |
331 | return -ENOMEM; | |
332 | } | |
333 | ||
334 | if (!p->cell2) { | |
335 | p->cell2 = alloc_prison_cell(cache); | |
336 | if (!p->cell2) | |
337 | return -ENOMEM; | |
338 | } | |
339 | ||
340 | return 0; | |
341 | } | |
342 | ||
343 | static void prealloc_free_structs(struct cache *cache, struct prealloc *p) | |
344 | { | |
345 | if (p->cell2) | |
346 | free_prison_cell(cache, p->cell2); | |
347 | ||
348 | if (p->cell1) | |
349 | free_prison_cell(cache, p->cell1); | |
350 | ||
351 | if (p->mg) | |
352 | mempool_free(p->mg, cache->migration_pool); | |
353 | } | |
354 | ||
355 | static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p) | |
356 | { | |
357 | struct dm_cache_migration *mg = p->mg; | |
358 | ||
359 | BUG_ON(!mg); | |
360 | p->mg = NULL; | |
361 | ||
362 | return mg; | |
363 | } | |
364 | ||
365 | /* | |
366 | * You must have a cell within the prealloc struct to return. If not this | |
367 | * function will BUG() rather than returning NULL. | |
368 | */ | |
369 | static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p) | |
370 | { | |
371 | struct dm_bio_prison_cell *r = NULL; | |
372 | ||
373 | if (p->cell1) { | |
374 | r = p->cell1; | |
375 | p->cell1 = NULL; | |
376 | ||
377 | } else if (p->cell2) { | |
378 | r = p->cell2; | |
379 | p->cell2 = NULL; | |
380 | } else | |
381 | BUG(); | |
382 | ||
383 | return r; | |
384 | } | |
385 | ||
386 | /* | |
387 | * You can't have more than two cells in a prealloc struct. BUG() will be | |
388 | * called if you try and overfill. | |
389 | */ | |
390 | static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell) | |
391 | { | |
392 | if (!p->cell2) | |
393 | p->cell2 = cell; | |
394 | ||
395 | else if (!p->cell1) | |
396 | p->cell1 = cell; | |
397 | ||
398 | else | |
399 | BUG(); | |
400 | } | |
401 | ||
402 | /*----------------------------------------------------------------*/ | |
403 | ||
404 | static void build_key(dm_oblock_t oblock, struct dm_cell_key *key) | |
405 | { | |
406 | key->virtual = 0; | |
407 | key->dev = 0; | |
408 | key->block = from_oblock(oblock); | |
409 | } | |
410 | ||
411 | /* | |
412 | * The caller hands in a preallocated cell, and a free function for it. | |
413 | * The cell will be freed if there's an error, or if it wasn't used because | |
414 | * a cell with that key already exists. | |
415 | */ | |
416 | typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell); | |
417 | ||
418 | static int bio_detain(struct cache *cache, dm_oblock_t oblock, | |
419 | struct bio *bio, struct dm_bio_prison_cell *cell_prealloc, | |
420 | cell_free_fn free_fn, void *free_context, | |
421 | struct dm_bio_prison_cell **cell_result) | |
422 | { | |
423 | int r; | |
424 | struct dm_cell_key key; | |
425 | ||
426 | build_key(oblock, &key); | |
427 | r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result); | |
428 | if (r) | |
429 | free_fn(free_context, cell_prealloc); | |
430 | ||
431 | return r; | |
432 | } | |
433 | ||
434 | static int get_cell(struct cache *cache, | |
435 | dm_oblock_t oblock, | |
436 | struct prealloc *structs, | |
437 | struct dm_bio_prison_cell **cell_result) | |
438 | { | |
439 | int r; | |
440 | struct dm_cell_key key; | |
441 | struct dm_bio_prison_cell *cell_prealloc; | |
442 | ||
443 | cell_prealloc = prealloc_get_cell(structs); | |
444 | ||
445 | build_key(oblock, &key); | |
446 | r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result); | |
447 | if (r) | |
448 | prealloc_put_cell(structs, cell_prealloc); | |
449 | ||
450 | return r; | |
451 | } | |
452 | ||
aeed1420 | 453 | /*----------------------------------------------------------------*/ |
c6b4fcba JT |
454 | |
455 | static bool is_dirty(struct cache *cache, dm_cblock_t b) | |
456 | { | |
457 | return test_bit(from_cblock(b), cache->dirty_bitset); | |
458 | } | |
459 | ||
460 | static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | |
461 | { | |
462 | if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
463 | cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) + 1); | |
464 | policy_set_dirty(cache->policy, oblock); | |
465 | } | |
466 | } | |
467 | ||
468 | static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | |
469 | { | |
470 | if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
471 | policy_clear_dirty(cache->policy, oblock); | |
472 | cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) - 1); | |
473 | if (!from_cblock(cache->nr_dirty)) | |
474 | dm_table_event(cache->ti->table); | |
475 | } | |
476 | } | |
477 | ||
478 | /*----------------------------------------------------------------*/ | |
aeed1420 | 479 | |
c6b4fcba JT |
480 | static bool block_size_is_power_of_two(struct cache *cache) |
481 | { | |
482 | return cache->sectors_per_block_shift >= 0; | |
483 | } | |
484 | ||
43aeaa29 MP |
485 | /* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */ |
486 | #if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6 | |
487 | __always_inline | |
488 | #endif | |
414dd67d JT |
489 | static dm_block_t block_div(dm_block_t b, uint32_t n) |
490 | { | |
491 | do_div(b, n); | |
492 | ||
493 | return b; | |
494 | } | |
495 | ||
c6b4fcba JT |
496 | static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) |
497 | { | |
414dd67d | 498 | uint32_t discard_blocks = cache->discard_block_size; |
c6b4fcba JT |
499 | dm_block_t b = from_oblock(oblock); |
500 | ||
501 | if (!block_size_is_power_of_two(cache)) | |
414dd67d | 502 | discard_blocks = discard_blocks / cache->sectors_per_block; |
c6b4fcba JT |
503 | else |
504 | discard_blocks >>= cache->sectors_per_block_shift; | |
505 | ||
414dd67d | 506 | b = block_div(b, discard_blocks); |
c6b4fcba JT |
507 | |
508 | return to_dblock(b); | |
509 | } | |
510 | ||
511 | static void set_discard(struct cache *cache, dm_dblock_t b) | |
512 | { | |
513 | unsigned long flags; | |
514 | ||
515 | atomic_inc(&cache->stats.discard_count); | |
516 | ||
517 | spin_lock_irqsave(&cache->lock, flags); | |
518 | set_bit(from_dblock(b), cache->discard_bitset); | |
519 | spin_unlock_irqrestore(&cache->lock, flags); | |
520 | } | |
521 | ||
522 | static void clear_discard(struct cache *cache, dm_dblock_t b) | |
523 | { | |
524 | unsigned long flags; | |
525 | ||
526 | spin_lock_irqsave(&cache->lock, flags); | |
527 | clear_bit(from_dblock(b), cache->discard_bitset); | |
528 | spin_unlock_irqrestore(&cache->lock, flags); | |
529 | } | |
530 | ||
531 | static bool is_discarded(struct cache *cache, dm_dblock_t b) | |
532 | { | |
533 | int r; | |
534 | unsigned long flags; | |
535 | ||
536 | spin_lock_irqsave(&cache->lock, flags); | |
537 | r = test_bit(from_dblock(b), cache->discard_bitset); | |
538 | spin_unlock_irqrestore(&cache->lock, flags); | |
539 | ||
540 | return r; | |
541 | } | |
542 | ||
543 | static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) | |
544 | { | |
545 | int r; | |
546 | unsigned long flags; | |
547 | ||
548 | spin_lock_irqsave(&cache->lock, flags); | |
549 | r = test_bit(from_dblock(oblock_to_dblock(cache, b)), | |
550 | cache->discard_bitset); | |
551 | spin_unlock_irqrestore(&cache->lock, flags); | |
552 | ||
553 | return r; | |
554 | } | |
555 | ||
556 | /*----------------------------------------------------------------*/ | |
557 | ||
558 | static void load_stats(struct cache *cache) | |
559 | { | |
560 | struct dm_cache_statistics stats; | |
561 | ||
562 | dm_cache_metadata_get_stats(cache->cmd, &stats); | |
563 | atomic_set(&cache->stats.read_hit, stats.read_hits); | |
564 | atomic_set(&cache->stats.read_miss, stats.read_misses); | |
565 | atomic_set(&cache->stats.write_hit, stats.write_hits); | |
566 | atomic_set(&cache->stats.write_miss, stats.write_misses); | |
567 | } | |
568 | ||
569 | static void save_stats(struct cache *cache) | |
570 | { | |
571 | struct dm_cache_statistics stats; | |
572 | ||
573 | stats.read_hits = atomic_read(&cache->stats.read_hit); | |
574 | stats.read_misses = atomic_read(&cache->stats.read_miss); | |
575 | stats.write_hits = atomic_read(&cache->stats.write_hit); | |
576 | stats.write_misses = atomic_read(&cache->stats.write_miss); | |
577 | ||
578 | dm_cache_metadata_set_stats(cache->cmd, &stats); | |
579 | } | |
580 | ||
581 | /*---------------------------------------------------------------- | |
582 | * Per bio data | |
583 | *--------------------------------------------------------------*/ | |
19b0092e MS |
584 | |
585 | /* | |
586 | * If using writeback, leave out struct per_bio_data's writethrough fields. | |
587 | */ | |
588 | #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) | |
589 | #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) | |
590 | ||
2ee57d58 JT |
591 | static bool writethrough_mode(struct cache_features *f) |
592 | { | |
593 | return f->io_mode == CM_IO_WRITETHROUGH; | |
594 | } | |
595 | ||
596 | static bool writeback_mode(struct cache_features *f) | |
597 | { | |
598 | return f->io_mode == CM_IO_WRITEBACK; | |
599 | } | |
600 | ||
601 | static bool passthrough_mode(struct cache_features *f) | |
602 | { | |
603 | return f->io_mode == CM_IO_PASSTHROUGH; | |
604 | } | |
605 | ||
19b0092e MS |
606 | static size_t get_per_bio_data_size(struct cache *cache) |
607 | { | |
2ee57d58 | 608 | return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; |
19b0092e MS |
609 | } |
610 | ||
611 | static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size) | |
c6b4fcba | 612 | { |
19b0092e | 613 | struct per_bio_data *pb = dm_per_bio_data(bio, data_size); |
c6b4fcba JT |
614 | BUG_ON(!pb); |
615 | return pb; | |
616 | } | |
617 | ||
19b0092e | 618 | static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size) |
c6b4fcba | 619 | { |
19b0092e | 620 | struct per_bio_data *pb = get_per_bio_data(bio, data_size); |
c6b4fcba JT |
621 | |
622 | pb->tick = false; | |
623 | pb->req_nr = dm_bio_get_target_bio_nr(bio); | |
624 | pb->all_io_entry = NULL; | |
625 | ||
626 | return pb; | |
627 | } | |
628 | ||
629 | /*---------------------------------------------------------------- | |
630 | * Remapping | |
631 | *--------------------------------------------------------------*/ | |
632 | static void remap_to_origin(struct cache *cache, struct bio *bio) | |
633 | { | |
634 | bio->bi_bdev = cache->origin_dev->bdev; | |
635 | } | |
636 | ||
637 | static void remap_to_cache(struct cache *cache, struct bio *bio, | |
638 | dm_cblock_t cblock) | |
639 | { | |
640 | sector_t bi_sector = bio->bi_sector; | |
641 | ||
642 | bio->bi_bdev = cache->cache_dev->bdev; | |
643 | if (!block_size_is_power_of_two(cache)) | |
644 | bio->bi_sector = (from_cblock(cblock) * cache->sectors_per_block) + | |
645 | sector_div(bi_sector, cache->sectors_per_block); | |
646 | else | |
647 | bio->bi_sector = (from_cblock(cblock) << cache->sectors_per_block_shift) | | |
648 | (bi_sector & (cache->sectors_per_block - 1)); | |
649 | } | |
650 | ||
651 | static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) | |
652 | { | |
653 | unsigned long flags; | |
19b0092e MS |
654 | size_t pb_data_size = get_per_bio_data_size(cache); |
655 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
656 | |
657 | spin_lock_irqsave(&cache->lock, flags); | |
658 | if (cache->need_tick_bio && | |
659 | !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) { | |
660 | pb->tick = true; | |
661 | cache->need_tick_bio = false; | |
662 | } | |
663 | spin_unlock_irqrestore(&cache->lock, flags); | |
664 | } | |
665 | ||
666 | static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, | |
667 | dm_oblock_t oblock) | |
668 | { | |
669 | check_if_tick_bio_needed(cache, bio); | |
670 | remap_to_origin(cache, bio); | |
671 | if (bio_data_dir(bio) == WRITE) | |
672 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | |
673 | } | |
674 | ||
675 | static void remap_to_cache_dirty(struct cache *cache, struct bio *bio, | |
676 | dm_oblock_t oblock, dm_cblock_t cblock) | |
677 | { | |
f8e5f01a | 678 | check_if_tick_bio_needed(cache, bio); |
c6b4fcba JT |
679 | remap_to_cache(cache, bio, cblock); |
680 | if (bio_data_dir(bio) == WRITE) { | |
681 | set_dirty(cache, oblock, cblock); | |
682 | clear_discard(cache, oblock_to_dblock(cache, oblock)); | |
683 | } | |
684 | } | |
685 | ||
686 | static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) | |
687 | { | |
688 | sector_t block_nr = bio->bi_sector; | |
689 | ||
690 | if (!block_size_is_power_of_two(cache)) | |
691 | (void) sector_div(block_nr, cache->sectors_per_block); | |
692 | else | |
693 | block_nr >>= cache->sectors_per_block_shift; | |
694 | ||
695 | return to_oblock(block_nr); | |
696 | } | |
697 | ||
698 | static int bio_triggers_commit(struct cache *cache, struct bio *bio) | |
699 | { | |
700 | return bio->bi_rw & (REQ_FLUSH | REQ_FUA); | |
701 | } | |
702 | ||
703 | static void issue(struct cache *cache, struct bio *bio) | |
704 | { | |
705 | unsigned long flags; | |
706 | ||
707 | if (!bio_triggers_commit(cache, bio)) { | |
708 | generic_make_request(bio); | |
709 | return; | |
710 | } | |
711 | ||
712 | /* | |
713 | * Batch together any bios that trigger commits and then issue a | |
714 | * single commit for them in do_worker(). | |
715 | */ | |
716 | spin_lock_irqsave(&cache->lock, flags); | |
717 | cache->commit_requested = true; | |
718 | bio_list_add(&cache->deferred_flush_bios, bio); | |
719 | spin_unlock_irqrestore(&cache->lock, flags); | |
720 | } | |
721 | ||
e2e74d61 JT |
722 | static void defer_writethrough_bio(struct cache *cache, struct bio *bio) |
723 | { | |
724 | unsigned long flags; | |
725 | ||
726 | spin_lock_irqsave(&cache->lock, flags); | |
727 | bio_list_add(&cache->deferred_writethrough_bios, bio); | |
728 | spin_unlock_irqrestore(&cache->lock, flags); | |
729 | ||
730 | wake_worker(cache); | |
731 | } | |
732 | ||
733 | static void writethrough_endio(struct bio *bio, int err) | |
734 | { | |
19b0092e | 735 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
c9d28d5d JT |
736 | |
737 | dm_unhook_bio(&pb->hook_info, bio); | |
e2e74d61 JT |
738 | |
739 | if (err) { | |
740 | bio_endio(bio, err); | |
741 | return; | |
742 | } | |
743 | ||
b844fe69 | 744 | dm_bio_restore(&pb->bio_details, bio); |
e2e74d61 JT |
745 | remap_to_cache(pb->cache, bio, pb->cblock); |
746 | ||
747 | /* | |
748 | * We can't issue this bio directly, since we're in interrupt | |
aeed1420 | 749 | * context. So it gets put on a bio list for processing by the |
e2e74d61 JT |
750 | * worker thread. |
751 | */ | |
752 | defer_writethrough_bio(pb->cache, bio); | |
753 | } | |
754 | ||
755 | /* | |
756 | * When running in writethrough mode we need to send writes to clean blocks | |
757 | * to both the cache and origin devices. In future we'd like to clone the | |
758 | * bio and send them in parallel, but for now we're doing them in | |
759 | * series as this is easier. | |
760 | */ | |
761 | static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, | |
762 | dm_oblock_t oblock, dm_cblock_t cblock) | |
763 | { | |
19b0092e | 764 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
e2e74d61 JT |
765 | |
766 | pb->cache = cache; | |
767 | pb->cblock = cblock; | |
c9d28d5d | 768 | dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL); |
b844fe69 | 769 | dm_bio_record(&pb->bio_details, bio); |
e2e74d61 JT |
770 | |
771 | remap_to_origin_clear_discard(pb->cache, bio, oblock); | |
772 | } | |
773 | ||
c6b4fcba JT |
774 | /*---------------------------------------------------------------- |
775 | * Migration processing | |
776 | * | |
777 | * Migration covers moving data from the origin device to the cache, or | |
778 | * vice versa. | |
779 | *--------------------------------------------------------------*/ | |
780 | static void free_migration(struct dm_cache_migration *mg) | |
781 | { | |
782 | mempool_free(mg, mg->cache->migration_pool); | |
783 | } | |
784 | ||
785 | static void inc_nr_migrations(struct cache *cache) | |
786 | { | |
787 | atomic_inc(&cache->nr_migrations); | |
788 | } | |
789 | ||
790 | static void dec_nr_migrations(struct cache *cache) | |
791 | { | |
792 | atomic_dec(&cache->nr_migrations); | |
793 | ||
794 | /* | |
795 | * Wake the worker in case we're suspending the target. | |
796 | */ | |
797 | wake_up(&cache->migration_wait); | |
798 | } | |
799 | ||
800 | static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | |
801 | bool holder) | |
802 | { | |
803 | (holder ? dm_cell_release : dm_cell_release_no_holder) | |
804 | (cache->prison, cell, &cache->deferred_bios); | |
805 | free_prison_cell(cache, cell); | |
806 | } | |
807 | ||
808 | static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | |
809 | bool holder) | |
810 | { | |
811 | unsigned long flags; | |
812 | ||
813 | spin_lock_irqsave(&cache->lock, flags); | |
814 | __cell_defer(cache, cell, holder); | |
815 | spin_unlock_irqrestore(&cache->lock, flags); | |
816 | ||
817 | wake_worker(cache); | |
818 | } | |
819 | ||
820 | static void cleanup_migration(struct dm_cache_migration *mg) | |
821 | { | |
66cb1910 | 822 | struct cache *cache = mg->cache; |
c6b4fcba | 823 | free_migration(mg); |
66cb1910 | 824 | dec_nr_migrations(cache); |
c6b4fcba JT |
825 | } |
826 | ||
827 | static void migration_failure(struct dm_cache_migration *mg) | |
828 | { | |
829 | struct cache *cache = mg->cache; | |
830 | ||
831 | if (mg->writeback) { | |
832 | DMWARN_LIMIT("writeback failed; couldn't copy block"); | |
833 | set_dirty(cache, mg->old_oblock, mg->cblock); | |
834 | cell_defer(cache, mg->old_ocell, false); | |
835 | ||
836 | } else if (mg->demote) { | |
837 | DMWARN_LIMIT("demotion failed; couldn't copy block"); | |
838 | policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); | |
839 | ||
80f659f3 | 840 | cell_defer(cache, mg->old_ocell, mg->promote ? false : true); |
c6b4fcba | 841 | if (mg->promote) |
80f659f3 | 842 | cell_defer(cache, mg->new_ocell, true); |
c6b4fcba JT |
843 | } else { |
844 | DMWARN_LIMIT("promotion failed; couldn't copy block"); | |
845 | policy_remove_mapping(cache->policy, mg->new_oblock); | |
80f659f3 | 846 | cell_defer(cache, mg->new_ocell, true); |
c6b4fcba JT |
847 | } |
848 | ||
849 | cleanup_migration(mg); | |
850 | } | |
851 | ||
852 | static void migration_success_pre_commit(struct dm_cache_migration *mg) | |
853 | { | |
854 | unsigned long flags; | |
855 | struct cache *cache = mg->cache; | |
856 | ||
857 | if (mg->writeback) { | |
858 | cell_defer(cache, mg->old_ocell, false); | |
859 | clear_dirty(cache, mg->old_oblock, mg->cblock); | |
860 | cleanup_migration(mg); | |
861 | return; | |
862 | ||
863 | } else if (mg->demote) { | |
864 | if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) { | |
865 | DMWARN_LIMIT("demotion failed; couldn't update on disk metadata"); | |
866 | policy_force_mapping(cache->policy, mg->new_oblock, | |
867 | mg->old_oblock); | |
868 | if (mg->promote) | |
869 | cell_defer(cache, mg->new_ocell, true); | |
870 | cleanup_migration(mg); | |
871 | return; | |
872 | } | |
873 | } else { | |
874 | if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) { | |
875 | DMWARN_LIMIT("promotion failed; couldn't update on disk metadata"); | |
876 | policy_remove_mapping(cache->policy, mg->new_oblock); | |
877 | cleanup_migration(mg); | |
878 | return; | |
879 | } | |
880 | } | |
881 | ||
882 | spin_lock_irqsave(&cache->lock, flags); | |
883 | list_add_tail(&mg->list, &cache->need_commit_migrations); | |
884 | cache->commit_requested = true; | |
885 | spin_unlock_irqrestore(&cache->lock, flags); | |
886 | } | |
887 | ||
888 | static void migration_success_post_commit(struct dm_cache_migration *mg) | |
889 | { | |
890 | unsigned long flags; | |
891 | struct cache *cache = mg->cache; | |
892 | ||
893 | if (mg->writeback) { | |
894 | DMWARN("writeback unexpectedly triggered commit"); | |
895 | return; | |
896 | ||
897 | } else if (mg->demote) { | |
80f659f3 | 898 | cell_defer(cache, mg->old_ocell, mg->promote ? false : true); |
c6b4fcba JT |
899 | |
900 | if (mg->promote) { | |
901 | mg->demote = false; | |
902 | ||
903 | spin_lock_irqsave(&cache->lock, flags); | |
904 | list_add_tail(&mg->list, &cache->quiesced_migrations); | |
905 | spin_unlock_irqrestore(&cache->lock, flags); | |
906 | ||
907 | } else | |
908 | cleanup_migration(mg); | |
909 | ||
910 | } else { | |
c9d28d5d JT |
911 | if (mg->requeue_holder) |
912 | cell_defer(cache, mg->new_ocell, true); | |
913 | else { | |
914 | bio_endio(mg->new_ocell->holder, 0); | |
915 | cell_defer(cache, mg->new_ocell, false); | |
916 | } | |
c6b4fcba JT |
917 | clear_dirty(cache, mg->new_oblock, mg->cblock); |
918 | cleanup_migration(mg); | |
919 | } | |
920 | } | |
921 | ||
922 | static void copy_complete(int read_err, unsigned long write_err, void *context) | |
923 | { | |
924 | unsigned long flags; | |
925 | struct dm_cache_migration *mg = (struct dm_cache_migration *) context; | |
926 | struct cache *cache = mg->cache; | |
927 | ||
928 | if (read_err || write_err) | |
929 | mg->err = true; | |
930 | ||
931 | spin_lock_irqsave(&cache->lock, flags); | |
932 | list_add_tail(&mg->list, &cache->completed_migrations); | |
933 | spin_unlock_irqrestore(&cache->lock, flags); | |
934 | ||
935 | wake_worker(cache); | |
936 | } | |
937 | ||
938 | static void issue_copy_real(struct dm_cache_migration *mg) | |
939 | { | |
940 | int r; | |
941 | struct dm_io_region o_region, c_region; | |
942 | struct cache *cache = mg->cache; | |
943 | ||
944 | o_region.bdev = cache->origin_dev->bdev; | |
945 | o_region.count = cache->sectors_per_block; | |
946 | ||
947 | c_region.bdev = cache->cache_dev->bdev; | |
948 | c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block; | |
949 | c_region.count = cache->sectors_per_block; | |
950 | ||
951 | if (mg->writeback || mg->demote) { | |
952 | /* demote */ | |
953 | o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block; | |
954 | r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg); | |
955 | } else { | |
956 | /* promote */ | |
957 | o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block; | |
958 | r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg); | |
959 | } | |
960 | ||
2c2263c9 HM |
961 | if (r < 0) { |
962 | DMERR_LIMIT("issuing migration failed"); | |
c6b4fcba | 963 | migration_failure(mg); |
2c2263c9 | 964 | } |
c6b4fcba JT |
965 | } |
966 | ||
c9d28d5d JT |
967 | static void overwrite_endio(struct bio *bio, int err) |
968 | { | |
969 | struct dm_cache_migration *mg = bio->bi_private; | |
970 | struct cache *cache = mg->cache; | |
971 | size_t pb_data_size = get_per_bio_data_size(cache); | |
972 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
973 | unsigned long flags; | |
974 | ||
975 | if (err) | |
976 | mg->err = true; | |
977 | ||
978 | spin_lock_irqsave(&cache->lock, flags); | |
979 | list_add_tail(&mg->list, &cache->completed_migrations); | |
980 | dm_unhook_bio(&pb->hook_info, bio); | |
981 | mg->requeue_holder = false; | |
982 | spin_unlock_irqrestore(&cache->lock, flags); | |
983 | ||
984 | wake_worker(cache); | |
985 | } | |
986 | ||
987 | static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio) | |
988 | { | |
989 | size_t pb_data_size = get_per_bio_data_size(mg->cache); | |
990 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
991 | ||
992 | dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg); | |
993 | remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock); | |
994 | generic_make_request(bio); | |
995 | } | |
996 | ||
997 | static bool bio_writes_complete_block(struct cache *cache, struct bio *bio) | |
998 | { | |
999 | return (bio_data_dir(bio) == WRITE) && | |
1000 | (bio->bi_size == (cache->sectors_per_block << SECTOR_SHIFT)); | |
1001 | } | |
1002 | ||
c6b4fcba JT |
1003 | static void avoid_copy(struct dm_cache_migration *mg) |
1004 | { | |
1005 | atomic_inc(&mg->cache->stats.copies_avoided); | |
1006 | migration_success_pre_commit(mg); | |
1007 | } | |
1008 | ||
1009 | static void issue_copy(struct dm_cache_migration *mg) | |
1010 | { | |
1011 | bool avoid; | |
1012 | struct cache *cache = mg->cache; | |
1013 | ||
1014 | if (mg->writeback || mg->demote) | |
1015 | avoid = !is_dirty(cache, mg->cblock) || | |
1016 | is_discarded_oblock(cache, mg->old_oblock); | |
c9d28d5d JT |
1017 | else { |
1018 | struct bio *bio = mg->new_ocell->holder; | |
1019 | ||
c6b4fcba JT |
1020 | avoid = is_discarded_oblock(cache, mg->new_oblock); |
1021 | ||
c9d28d5d JT |
1022 | if (!avoid && bio_writes_complete_block(cache, bio)) { |
1023 | issue_overwrite(mg, bio); | |
1024 | return; | |
1025 | } | |
1026 | } | |
1027 | ||
c6b4fcba JT |
1028 | avoid ? avoid_copy(mg) : issue_copy_real(mg); |
1029 | } | |
1030 | ||
1031 | static void complete_migration(struct dm_cache_migration *mg) | |
1032 | { | |
1033 | if (mg->err) | |
1034 | migration_failure(mg); | |
1035 | else | |
1036 | migration_success_pre_commit(mg); | |
1037 | } | |
1038 | ||
1039 | static void process_migrations(struct cache *cache, struct list_head *head, | |
1040 | void (*fn)(struct dm_cache_migration *)) | |
1041 | { | |
1042 | unsigned long flags; | |
1043 | struct list_head list; | |
1044 | struct dm_cache_migration *mg, *tmp; | |
1045 | ||
1046 | INIT_LIST_HEAD(&list); | |
1047 | spin_lock_irqsave(&cache->lock, flags); | |
1048 | list_splice_init(head, &list); | |
1049 | spin_unlock_irqrestore(&cache->lock, flags); | |
1050 | ||
1051 | list_for_each_entry_safe(mg, tmp, &list, list) | |
1052 | fn(mg); | |
1053 | } | |
1054 | ||
1055 | static void __queue_quiesced_migration(struct dm_cache_migration *mg) | |
1056 | { | |
1057 | list_add_tail(&mg->list, &mg->cache->quiesced_migrations); | |
1058 | } | |
1059 | ||
1060 | static void queue_quiesced_migration(struct dm_cache_migration *mg) | |
1061 | { | |
1062 | unsigned long flags; | |
1063 | struct cache *cache = mg->cache; | |
1064 | ||
1065 | spin_lock_irqsave(&cache->lock, flags); | |
1066 | __queue_quiesced_migration(mg); | |
1067 | spin_unlock_irqrestore(&cache->lock, flags); | |
1068 | ||
1069 | wake_worker(cache); | |
1070 | } | |
1071 | ||
1072 | static void queue_quiesced_migrations(struct cache *cache, struct list_head *work) | |
1073 | { | |
1074 | unsigned long flags; | |
1075 | struct dm_cache_migration *mg, *tmp; | |
1076 | ||
1077 | spin_lock_irqsave(&cache->lock, flags); | |
1078 | list_for_each_entry_safe(mg, tmp, work, list) | |
1079 | __queue_quiesced_migration(mg); | |
1080 | spin_unlock_irqrestore(&cache->lock, flags); | |
1081 | ||
1082 | wake_worker(cache); | |
1083 | } | |
1084 | ||
1085 | static void check_for_quiesced_migrations(struct cache *cache, | |
1086 | struct per_bio_data *pb) | |
1087 | { | |
1088 | struct list_head work; | |
1089 | ||
1090 | if (!pb->all_io_entry) | |
1091 | return; | |
1092 | ||
1093 | INIT_LIST_HEAD(&work); | |
1094 | if (pb->all_io_entry) | |
1095 | dm_deferred_entry_dec(pb->all_io_entry, &work); | |
1096 | ||
1097 | if (!list_empty(&work)) | |
1098 | queue_quiesced_migrations(cache, &work); | |
1099 | } | |
1100 | ||
1101 | static void quiesce_migration(struct dm_cache_migration *mg) | |
1102 | { | |
1103 | if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list)) | |
1104 | queue_quiesced_migration(mg); | |
1105 | } | |
1106 | ||
1107 | static void promote(struct cache *cache, struct prealloc *structs, | |
1108 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1109 | struct dm_bio_prison_cell *cell) | |
1110 | { | |
1111 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1112 | ||
1113 | mg->err = false; | |
1114 | mg->writeback = false; | |
1115 | mg->demote = false; | |
1116 | mg->promote = true; | |
c9d28d5d | 1117 | mg->requeue_holder = true; |
c6b4fcba JT |
1118 | mg->cache = cache; |
1119 | mg->new_oblock = oblock; | |
1120 | mg->cblock = cblock; | |
1121 | mg->old_ocell = NULL; | |
1122 | mg->new_ocell = cell; | |
1123 | mg->start_jiffies = jiffies; | |
1124 | ||
1125 | inc_nr_migrations(cache); | |
1126 | quiesce_migration(mg); | |
1127 | } | |
1128 | ||
1129 | static void writeback(struct cache *cache, struct prealloc *structs, | |
1130 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1131 | struct dm_bio_prison_cell *cell) | |
1132 | { | |
1133 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1134 | ||
1135 | mg->err = false; | |
1136 | mg->writeback = true; | |
1137 | mg->demote = false; | |
1138 | mg->promote = false; | |
c9d28d5d | 1139 | mg->requeue_holder = true; |
c6b4fcba JT |
1140 | mg->cache = cache; |
1141 | mg->old_oblock = oblock; | |
1142 | mg->cblock = cblock; | |
1143 | mg->old_ocell = cell; | |
1144 | mg->new_ocell = NULL; | |
1145 | mg->start_jiffies = jiffies; | |
1146 | ||
1147 | inc_nr_migrations(cache); | |
1148 | quiesce_migration(mg); | |
1149 | } | |
1150 | ||
1151 | static void demote_then_promote(struct cache *cache, struct prealloc *structs, | |
1152 | dm_oblock_t old_oblock, dm_oblock_t new_oblock, | |
1153 | dm_cblock_t cblock, | |
1154 | struct dm_bio_prison_cell *old_ocell, | |
1155 | struct dm_bio_prison_cell *new_ocell) | |
1156 | { | |
1157 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1158 | ||
1159 | mg->err = false; | |
1160 | mg->writeback = false; | |
1161 | mg->demote = true; | |
1162 | mg->promote = true; | |
c9d28d5d | 1163 | mg->requeue_holder = true; |
c6b4fcba JT |
1164 | mg->cache = cache; |
1165 | mg->old_oblock = old_oblock; | |
1166 | mg->new_oblock = new_oblock; | |
1167 | mg->cblock = cblock; | |
1168 | mg->old_ocell = old_ocell; | |
1169 | mg->new_ocell = new_ocell; | |
1170 | mg->start_jiffies = jiffies; | |
1171 | ||
1172 | inc_nr_migrations(cache); | |
1173 | quiesce_migration(mg); | |
1174 | } | |
1175 | ||
2ee57d58 JT |
1176 | /* |
1177 | * Invalidate a cache entry. No writeback occurs; any changes in the cache | |
1178 | * block are thrown away. | |
1179 | */ | |
1180 | static void invalidate(struct cache *cache, struct prealloc *structs, | |
1181 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1182 | struct dm_bio_prison_cell *cell) | |
1183 | { | |
1184 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1185 | ||
1186 | mg->err = false; | |
1187 | mg->writeback = false; | |
1188 | mg->demote = true; | |
1189 | mg->promote = false; | |
1190 | mg->requeue_holder = true; | |
1191 | mg->cache = cache; | |
1192 | mg->old_oblock = oblock; | |
1193 | mg->cblock = cblock; | |
1194 | mg->old_ocell = cell; | |
1195 | mg->new_ocell = NULL; | |
1196 | mg->start_jiffies = jiffies; | |
1197 | ||
1198 | inc_nr_migrations(cache); | |
1199 | quiesce_migration(mg); | |
1200 | } | |
1201 | ||
c6b4fcba JT |
1202 | /*---------------------------------------------------------------- |
1203 | * bio processing | |
1204 | *--------------------------------------------------------------*/ | |
1205 | static void defer_bio(struct cache *cache, struct bio *bio) | |
1206 | { | |
1207 | unsigned long flags; | |
1208 | ||
1209 | spin_lock_irqsave(&cache->lock, flags); | |
1210 | bio_list_add(&cache->deferred_bios, bio); | |
1211 | spin_unlock_irqrestore(&cache->lock, flags); | |
1212 | ||
1213 | wake_worker(cache); | |
1214 | } | |
1215 | ||
1216 | static void process_flush_bio(struct cache *cache, struct bio *bio) | |
1217 | { | |
19b0092e MS |
1218 | size_t pb_data_size = get_per_bio_data_size(cache); |
1219 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
1220 | |
1221 | BUG_ON(bio->bi_size); | |
1222 | if (!pb->req_nr) | |
1223 | remap_to_origin(cache, bio); | |
1224 | else | |
1225 | remap_to_cache(cache, bio, 0); | |
1226 | ||
1227 | issue(cache, bio); | |
1228 | } | |
1229 | ||
1230 | /* | |
1231 | * People generally discard large parts of a device, eg, the whole device | |
1232 | * when formatting. Splitting these large discards up into cache block | |
1233 | * sized ios and then quiescing (always neccessary for discard) takes too | |
1234 | * long. | |
1235 | * | |
1236 | * We keep it simple, and allow any size of discard to come in, and just | |
1237 | * mark off blocks on the discard bitset. No passdown occurs! | |
1238 | * | |
1239 | * To implement passdown we need to change the bio_prison such that a cell | |
1240 | * can have a key that spans many blocks. | |
1241 | */ | |
1242 | static void process_discard_bio(struct cache *cache, struct bio *bio) | |
1243 | { | |
1244 | dm_block_t start_block = dm_sector_div_up(bio->bi_sector, | |
1245 | cache->discard_block_size); | |
1246 | dm_block_t end_block = bio->bi_sector + bio_sectors(bio); | |
1247 | dm_block_t b; | |
1248 | ||
414dd67d | 1249 | end_block = block_div(end_block, cache->discard_block_size); |
c6b4fcba JT |
1250 | |
1251 | for (b = start_block; b < end_block; b++) | |
1252 | set_discard(cache, to_dblock(b)); | |
1253 | ||
1254 | bio_endio(bio, 0); | |
1255 | } | |
1256 | ||
1257 | static bool spare_migration_bandwidth(struct cache *cache) | |
1258 | { | |
1259 | sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) * | |
1260 | cache->sectors_per_block; | |
1261 | return current_volume < cache->migration_threshold; | |
1262 | } | |
1263 | ||
c6b4fcba JT |
1264 | static void inc_hit_counter(struct cache *cache, struct bio *bio) |
1265 | { | |
1266 | atomic_inc(bio_data_dir(bio) == READ ? | |
1267 | &cache->stats.read_hit : &cache->stats.write_hit); | |
1268 | } | |
1269 | ||
1270 | static void inc_miss_counter(struct cache *cache, struct bio *bio) | |
1271 | { | |
1272 | atomic_inc(bio_data_dir(bio) == READ ? | |
1273 | &cache->stats.read_miss : &cache->stats.write_miss); | |
1274 | } | |
1275 | ||
2ee57d58 JT |
1276 | static void issue_cache_bio(struct cache *cache, struct bio *bio, |
1277 | struct per_bio_data *pb, | |
1278 | dm_oblock_t oblock, dm_cblock_t cblock) | |
1279 | { | |
1280 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
1281 | remap_to_cache_dirty(cache, bio, oblock, cblock); | |
1282 | issue(cache, bio); | |
1283 | } | |
1284 | ||
c6b4fcba JT |
1285 | static void process_bio(struct cache *cache, struct prealloc *structs, |
1286 | struct bio *bio) | |
1287 | { | |
1288 | int r; | |
1289 | bool release_cell = true; | |
1290 | dm_oblock_t block = get_bio_block(cache, bio); | |
1291 | struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell; | |
1292 | struct policy_result lookup_result; | |
19b0092e MS |
1293 | size_t pb_data_size = get_per_bio_data_size(cache); |
1294 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba | 1295 | bool discarded_block = is_discarded_oblock(cache, block); |
2ee57d58 JT |
1296 | bool passthrough = passthrough_mode(&cache->features); |
1297 | bool can_migrate = !passthrough && (discarded_block || spare_migration_bandwidth(cache)); | |
c6b4fcba JT |
1298 | |
1299 | /* | |
1300 | * Check to see if that block is currently migrating. | |
1301 | */ | |
1302 | cell_prealloc = prealloc_get_cell(structs); | |
1303 | r = bio_detain(cache, block, bio, cell_prealloc, | |
1304 | (cell_free_fn) prealloc_put_cell, | |
1305 | structs, &new_ocell); | |
1306 | if (r > 0) | |
1307 | return; | |
1308 | ||
1309 | r = policy_map(cache->policy, block, true, can_migrate, discarded_block, | |
1310 | bio, &lookup_result); | |
1311 | ||
1312 | if (r == -EWOULDBLOCK) | |
1313 | /* migration has been denied */ | |
1314 | lookup_result.op = POLICY_MISS; | |
1315 | ||
1316 | switch (lookup_result.op) { | |
1317 | case POLICY_HIT: | |
2ee57d58 JT |
1318 | if (passthrough) { |
1319 | inc_miss_counter(cache, bio); | |
c6b4fcba | 1320 | |
2ee57d58 JT |
1321 | /* |
1322 | * Passthrough always maps to the origin, | |
1323 | * invalidating any cache blocks that are written | |
1324 | * to. | |
1325 | */ | |
1326 | ||
1327 | if (bio_data_dir(bio) == WRITE) { | |
1328 | atomic_inc(&cache->stats.demotion); | |
1329 | invalidate(cache, structs, block, lookup_result.cblock, new_ocell); | |
1330 | release_cell = false; | |
1331 | ||
1332 | } else { | |
1333 | /* FIXME: factor out issue_origin() */ | |
1334 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
1335 | remap_to_origin_clear_discard(cache, bio, block); | |
1336 | issue(cache, bio); | |
1337 | } | |
1338 | } else { | |
1339 | inc_hit_counter(cache, bio); | |
1340 | ||
1341 | if (bio_data_dir(bio) == WRITE && | |
1342 | writethrough_mode(&cache->features) && | |
1343 | !is_dirty(cache, lookup_result.cblock)) { | |
1344 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
1345 | remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); | |
1346 | issue(cache, bio); | |
1347 | } else | |
1348 | issue_cache_bio(cache, bio, pb, block, lookup_result.cblock); | |
1349 | } | |
c6b4fcba | 1350 | |
c6b4fcba JT |
1351 | break; |
1352 | ||
1353 | case POLICY_MISS: | |
1354 | inc_miss_counter(cache, bio); | |
1355 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
e2e74d61 JT |
1356 | remap_to_origin_clear_discard(cache, bio, block); |
1357 | issue(cache, bio); | |
c6b4fcba JT |
1358 | break; |
1359 | ||
1360 | case POLICY_NEW: | |
1361 | atomic_inc(&cache->stats.promotion); | |
1362 | promote(cache, structs, block, lookup_result.cblock, new_ocell); | |
1363 | release_cell = false; | |
1364 | break; | |
1365 | ||
1366 | case POLICY_REPLACE: | |
1367 | cell_prealloc = prealloc_get_cell(structs); | |
1368 | r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc, | |
1369 | (cell_free_fn) prealloc_put_cell, | |
1370 | structs, &old_ocell); | |
1371 | if (r > 0) { | |
1372 | /* | |
1373 | * We have to be careful to avoid lock inversion of | |
1374 | * the cells. So we back off, and wait for the | |
1375 | * old_ocell to become free. | |
1376 | */ | |
1377 | policy_force_mapping(cache->policy, block, | |
1378 | lookup_result.old_oblock); | |
1379 | atomic_inc(&cache->stats.cache_cell_clash); | |
1380 | break; | |
1381 | } | |
1382 | atomic_inc(&cache->stats.demotion); | |
1383 | atomic_inc(&cache->stats.promotion); | |
1384 | ||
1385 | demote_then_promote(cache, structs, lookup_result.old_oblock, | |
1386 | block, lookup_result.cblock, | |
1387 | old_ocell, new_ocell); | |
1388 | release_cell = false; | |
1389 | break; | |
1390 | ||
1391 | default: | |
1392 | DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__, | |
1393 | (unsigned) lookup_result.op); | |
1394 | bio_io_error(bio); | |
1395 | } | |
1396 | ||
1397 | if (release_cell) | |
1398 | cell_defer(cache, new_ocell, false); | |
1399 | } | |
1400 | ||
1401 | static int need_commit_due_to_time(struct cache *cache) | |
1402 | { | |
1403 | return jiffies < cache->last_commit_jiffies || | |
1404 | jiffies > cache->last_commit_jiffies + COMMIT_PERIOD; | |
1405 | } | |
1406 | ||
1407 | static int commit_if_needed(struct cache *cache) | |
1408 | { | |
ffcbcb67 HM |
1409 | int r = 0; |
1410 | ||
1411 | if ((cache->commit_requested || need_commit_due_to_time(cache)) && | |
1412 | dm_cache_changed_this_transaction(cache->cmd)) { | |
c6b4fcba | 1413 | atomic_inc(&cache->stats.commit_count); |
c6b4fcba | 1414 | cache->commit_requested = false; |
ffcbcb67 HM |
1415 | r = dm_cache_commit(cache->cmd, false); |
1416 | cache->last_commit_jiffies = jiffies; | |
c6b4fcba JT |
1417 | } |
1418 | ||
ffcbcb67 | 1419 | return r; |
c6b4fcba JT |
1420 | } |
1421 | ||
1422 | static void process_deferred_bios(struct cache *cache) | |
1423 | { | |
1424 | unsigned long flags; | |
1425 | struct bio_list bios; | |
1426 | struct bio *bio; | |
1427 | struct prealloc structs; | |
1428 | ||
1429 | memset(&structs, 0, sizeof(structs)); | |
1430 | bio_list_init(&bios); | |
1431 | ||
1432 | spin_lock_irqsave(&cache->lock, flags); | |
1433 | bio_list_merge(&bios, &cache->deferred_bios); | |
1434 | bio_list_init(&cache->deferred_bios); | |
1435 | spin_unlock_irqrestore(&cache->lock, flags); | |
1436 | ||
1437 | while (!bio_list_empty(&bios)) { | |
1438 | /* | |
1439 | * If we've got no free migration structs, and processing | |
1440 | * this bio might require one, we pause until there are some | |
1441 | * prepared mappings to process. | |
1442 | */ | |
1443 | if (prealloc_data_structs(cache, &structs)) { | |
1444 | spin_lock_irqsave(&cache->lock, flags); | |
1445 | bio_list_merge(&cache->deferred_bios, &bios); | |
1446 | spin_unlock_irqrestore(&cache->lock, flags); | |
1447 | break; | |
1448 | } | |
1449 | ||
1450 | bio = bio_list_pop(&bios); | |
1451 | ||
1452 | if (bio->bi_rw & REQ_FLUSH) | |
1453 | process_flush_bio(cache, bio); | |
1454 | else if (bio->bi_rw & REQ_DISCARD) | |
1455 | process_discard_bio(cache, bio); | |
1456 | else | |
1457 | process_bio(cache, &structs, bio); | |
1458 | } | |
1459 | ||
1460 | prealloc_free_structs(cache, &structs); | |
1461 | } | |
1462 | ||
1463 | static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) | |
1464 | { | |
1465 | unsigned long flags; | |
1466 | struct bio_list bios; | |
1467 | struct bio *bio; | |
1468 | ||
1469 | bio_list_init(&bios); | |
1470 | ||
1471 | spin_lock_irqsave(&cache->lock, flags); | |
1472 | bio_list_merge(&bios, &cache->deferred_flush_bios); | |
1473 | bio_list_init(&cache->deferred_flush_bios); | |
1474 | spin_unlock_irqrestore(&cache->lock, flags); | |
1475 | ||
1476 | while ((bio = bio_list_pop(&bios))) | |
1477 | submit_bios ? generic_make_request(bio) : bio_io_error(bio); | |
1478 | } | |
1479 | ||
e2e74d61 JT |
1480 | static void process_deferred_writethrough_bios(struct cache *cache) |
1481 | { | |
1482 | unsigned long flags; | |
1483 | struct bio_list bios; | |
1484 | struct bio *bio; | |
1485 | ||
1486 | bio_list_init(&bios); | |
1487 | ||
1488 | spin_lock_irqsave(&cache->lock, flags); | |
1489 | bio_list_merge(&bios, &cache->deferred_writethrough_bios); | |
1490 | bio_list_init(&cache->deferred_writethrough_bios); | |
1491 | spin_unlock_irqrestore(&cache->lock, flags); | |
1492 | ||
1493 | while ((bio = bio_list_pop(&bios))) | |
1494 | generic_make_request(bio); | |
1495 | } | |
1496 | ||
c6b4fcba JT |
1497 | static void writeback_some_dirty_blocks(struct cache *cache) |
1498 | { | |
1499 | int r = 0; | |
1500 | dm_oblock_t oblock; | |
1501 | dm_cblock_t cblock; | |
1502 | struct prealloc structs; | |
1503 | struct dm_bio_prison_cell *old_ocell; | |
1504 | ||
1505 | memset(&structs, 0, sizeof(structs)); | |
1506 | ||
1507 | while (spare_migration_bandwidth(cache)) { | |
1508 | if (prealloc_data_structs(cache, &structs)) | |
1509 | break; | |
1510 | ||
1511 | r = policy_writeback_work(cache->policy, &oblock, &cblock); | |
1512 | if (r) | |
1513 | break; | |
1514 | ||
1515 | r = get_cell(cache, oblock, &structs, &old_ocell); | |
1516 | if (r) { | |
1517 | policy_set_dirty(cache->policy, oblock); | |
1518 | break; | |
1519 | } | |
1520 | ||
1521 | writeback(cache, &structs, oblock, cblock, old_ocell); | |
1522 | } | |
1523 | ||
1524 | prealloc_free_structs(cache, &structs); | |
1525 | } | |
1526 | ||
1527 | /*---------------------------------------------------------------- | |
1528 | * Main worker loop | |
1529 | *--------------------------------------------------------------*/ | |
66cb1910 | 1530 | static bool is_quiescing(struct cache *cache) |
c6b4fcba | 1531 | { |
238f8363 | 1532 | return atomic_read(&cache->quiescing); |
c6b4fcba JT |
1533 | } |
1534 | ||
66cb1910 JT |
1535 | static void ack_quiescing(struct cache *cache) |
1536 | { | |
1537 | if (is_quiescing(cache)) { | |
1538 | atomic_inc(&cache->quiescing_ack); | |
1539 | wake_up(&cache->quiescing_wait); | |
1540 | } | |
1541 | } | |
1542 | ||
1543 | static void wait_for_quiescing_ack(struct cache *cache) | |
1544 | { | |
1545 | wait_event(cache->quiescing_wait, atomic_read(&cache->quiescing_ack)); | |
1546 | } | |
1547 | ||
1548 | static void start_quiescing(struct cache *cache) | |
c6b4fcba | 1549 | { |
238f8363 | 1550 | atomic_inc(&cache->quiescing); |
66cb1910 | 1551 | wait_for_quiescing_ack(cache); |
c6b4fcba JT |
1552 | } |
1553 | ||
66cb1910 | 1554 | static void stop_quiescing(struct cache *cache) |
c6b4fcba | 1555 | { |
238f8363 | 1556 | atomic_set(&cache->quiescing, 0); |
66cb1910 | 1557 | atomic_set(&cache->quiescing_ack, 0); |
c6b4fcba JT |
1558 | } |
1559 | ||
1560 | static void wait_for_migrations(struct cache *cache) | |
1561 | { | |
1562 | wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations)); | |
1563 | } | |
1564 | ||
1565 | static void stop_worker(struct cache *cache) | |
1566 | { | |
1567 | cancel_delayed_work(&cache->waker); | |
1568 | flush_workqueue(cache->wq); | |
1569 | } | |
1570 | ||
1571 | static void requeue_deferred_io(struct cache *cache) | |
1572 | { | |
1573 | struct bio *bio; | |
1574 | struct bio_list bios; | |
1575 | ||
1576 | bio_list_init(&bios); | |
1577 | bio_list_merge(&bios, &cache->deferred_bios); | |
1578 | bio_list_init(&cache->deferred_bios); | |
1579 | ||
1580 | while ((bio = bio_list_pop(&bios))) | |
1581 | bio_endio(bio, DM_ENDIO_REQUEUE); | |
1582 | } | |
1583 | ||
1584 | static int more_work(struct cache *cache) | |
1585 | { | |
1586 | if (is_quiescing(cache)) | |
1587 | return !list_empty(&cache->quiesced_migrations) || | |
1588 | !list_empty(&cache->completed_migrations) || | |
1589 | !list_empty(&cache->need_commit_migrations); | |
1590 | else | |
1591 | return !bio_list_empty(&cache->deferred_bios) || | |
1592 | !bio_list_empty(&cache->deferred_flush_bios) || | |
e2e74d61 | 1593 | !bio_list_empty(&cache->deferred_writethrough_bios) || |
c6b4fcba JT |
1594 | !list_empty(&cache->quiesced_migrations) || |
1595 | !list_empty(&cache->completed_migrations) || | |
1596 | !list_empty(&cache->need_commit_migrations); | |
1597 | } | |
1598 | ||
1599 | static void do_worker(struct work_struct *ws) | |
1600 | { | |
1601 | struct cache *cache = container_of(ws, struct cache, worker); | |
1602 | ||
1603 | do { | |
66cb1910 JT |
1604 | if (!is_quiescing(cache)) { |
1605 | writeback_some_dirty_blocks(cache); | |
1606 | process_deferred_writethrough_bios(cache); | |
c6b4fcba | 1607 | process_deferred_bios(cache); |
66cb1910 | 1608 | } |
c6b4fcba JT |
1609 | |
1610 | process_migrations(cache, &cache->quiesced_migrations, issue_copy); | |
1611 | process_migrations(cache, &cache->completed_migrations, complete_migration); | |
1612 | ||
c6b4fcba JT |
1613 | if (commit_if_needed(cache)) { |
1614 | process_deferred_flush_bios(cache, false); | |
1615 | ||
1616 | /* | |
1617 | * FIXME: rollback metadata or just go into a | |
1618 | * failure mode and error everything | |
1619 | */ | |
1620 | } else { | |
1621 | process_deferred_flush_bios(cache, true); | |
1622 | process_migrations(cache, &cache->need_commit_migrations, | |
1623 | migration_success_post_commit); | |
1624 | } | |
66cb1910 JT |
1625 | |
1626 | ack_quiescing(cache); | |
1627 | ||
c6b4fcba JT |
1628 | } while (more_work(cache)); |
1629 | } | |
1630 | ||
1631 | /* | |
1632 | * We want to commit periodically so that not too much | |
1633 | * unwritten metadata builds up. | |
1634 | */ | |
1635 | static void do_waker(struct work_struct *ws) | |
1636 | { | |
1637 | struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker); | |
f8350daf | 1638 | policy_tick(cache->policy); |
c6b4fcba JT |
1639 | wake_worker(cache); |
1640 | queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); | |
1641 | } | |
1642 | ||
1643 | /*----------------------------------------------------------------*/ | |
1644 | ||
1645 | static int is_congested(struct dm_dev *dev, int bdi_bits) | |
1646 | { | |
1647 | struct request_queue *q = bdev_get_queue(dev->bdev); | |
1648 | return bdi_congested(&q->backing_dev_info, bdi_bits); | |
1649 | } | |
1650 | ||
1651 | static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits) | |
1652 | { | |
1653 | struct cache *cache = container_of(cb, struct cache, callbacks); | |
1654 | ||
1655 | return is_congested(cache->origin_dev, bdi_bits) || | |
1656 | is_congested(cache->cache_dev, bdi_bits); | |
1657 | } | |
1658 | ||
1659 | /*---------------------------------------------------------------- | |
1660 | * Target methods | |
1661 | *--------------------------------------------------------------*/ | |
1662 | ||
1663 | /* | |
1664 | * This function gets called on the error paths of the constructor, so we | |
1665 | * have to cope with a partially initialised struct. | |
1666 | */ | |
1667 | static void destroy(struct cache *cache) | |
1668 | { | |
1669 | unsigned i; | |
1670 | ||
1671 | if (cache->next_migration) | |
1672 | mempool_free(cache->next_migration, cache->migration_pool); | |
1673 | ||
1674 | if (cache->migration_pool) | |
1675 | mempool_destroy(cache->migration_pool); | |
1676 | ||
1677 | if (cache->all_io_ds) | |
1678 | dm_deferred_set_destroy(cache->all_io_ds); | |
1679 | ||
1680 | if (cache->prison) | |
1681 | dm_bio_prison_destroy(cache->prison); | |
1682 | ||
1683 | if (cache->wq) | |
1684 | destroy_workqueue(cache->wq); | |
1685 | ||
1686 | if (cache->dirty_bitset) | |
1687 | free_bitset(cache->dirty_bitset); | |
1688 | ||
1689 | if (cache->discard_bitset) | |
1690 | free_bitset(cache->discard_bitset); | |
1691 | ||
1692 | if (cache->copier) | |
1693 | dm_kcopyd_client_destroy(cache->copier); | |
1694 | ||
1695 | if (cache->cmd) | |
1696 | dm_cache_metadata_close(cache->cmd); | |
1697 | ||
1698 | if (cache->metadata_dev) | |
1699 | dm_put_device(cache->ti, cache->metadata_dev); | |
1700 | ||
1701 | if (cache->origin_dev) | |
1702 | dm_put_device(cache->ti, cache->origin_dev); | |
1703 | ||
1704 | if (cache->cache_dev) | |
1705 | dm_put_device(cache->ti, cache->cache_dev); | |
1706 | ||
1707 | if (cache->policy) | |
1708 | dm_cache_policy_destroy(cache->policy); | |
1709 | ||
1710 | for (i = 0; i < cache->nr_ctr_args ; i++) | |
1711 | kfree(cache->ctr_args[i]); | |
1712 | kfree(cache->ctr_args); | |
1713 | ||
1714 | kfree(cache); | |
1715 | } | |
1716 | ||
1717 | static void cache_dtr(struct dm_target *ti) | |
1718 | { | |
1719 | struct cache *cache = ti->private; | |
1720 | ||
1721 | destroy(cache); | |
1722 | } | |
1723 | ||
1724 | static sector_t get_dev_size(struct dm_dev *dev) | |
1725 | { | |
1726 | return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT; | |
1727 | } | |
1728 | ||
1729 | /*----------------------------------------------------------------*/ | |
1730 | ||
1731 | /* | |
1732 | * Construct a cache device mapping. | |
1733 | * | |
1734 | * cache <metadata dev> <cache dev> <origin dev> <block size> | |
1735 | * <#feature args> [<feature arg>]* | |
1736 | * <policy> <#policy args> [<policy arg>]* | |
1737 | * | |
1738 | * metadata dev : fast device holding the persistent metadata | |
1739 | * cache dev : fast device holding cached data blocks | |
1740 | * origin dev : slow device holding original data blocks | |
1741 | * block size : cache unit size in sectors | |
1742 | * | |
1743 | * #feature args : number of feature arguments passed | |
1744 | * feature args : writethrough. (The default is writeback.) | |
1745 | * | |
1746 | * policy : the replacement policy to use | |
1747 | * #policy args : an even number of policy arguments corresponding | |
1748 | * to key/value pairs passed to the policy | |
1749 | * policy args : key/value pairs passed to the policy | |
1750 | * E.g. 'sequential_threshold 1024' | |
1751 | * See cache-policies.txt for details. | |
1752 | * | |
1753 | * Optional feature arguments are: | |
1754 | * writethrough : write through caching that prohibits cache block | |
1755 | * content from being different from origin block content. | |
1756 | * Without this argument, the default behaviour is to write | |
1757 | * back cache block contents later for performance reasons, | |
1758 | * so they may differ from the corresponding origin blocks. | |
1759 | */ | |
1760 | struct cache_args { | |
1761 | struct dm_target *ti; | |
1762 | ||
1763 | struct dm_dev *metadata_dev; | |
1764 | ||
1765 | struct dm_dev *cache_dev; | |
1766 | sector_t cache_sectors; | |
1767 | ||
1768 | struct dm_dev *origin_dev; | |
1769 | sector_t origin_sectors; | |
1770 | ||
1771 | uint32_t block_size; | |
1772 | ||
1773 | const char *policy_name; | |
1774 | int policy_argc; | |
1775 | const char **policy_argv; | |
1776 | ||
1777 | struct cache_features features; | |
1778 | }; | |
1779 | ||
1780 | static void destroy_cache_args(struct cache_args *ca) | |
1781 | { | |
1782 | if (ca->metadata_dev) | |
1783 | dm_put_device(ca->ti, ca->metadata_dev); | |
1784 | ||
1785 | if (ca->cache_dev) | |
1786 | dm_put_device(ca->ti, ca->cache_dev); | |
1787 | ||
1788 | if (ca->origin_dev) | |
1789 | dm_put_device(ca->ti, ca->origin_dev); | |
1790 | ||
1791 | kfree(ca); | |
1792 | } | |
1793 | ||
1794 | static bool at_least_one_arg(struct dm_arg_set *as, char **error) | |
1795 | { | |
1796 | if (!as->argc) { | |
1797 | *error = "Insufficient args"; | |
1798 | return false; | |
1799 | } | |
1800 | ||
1801 | return true; | |
1802 | } | |
1803 | ||
1804 | static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1805 | char **error) | |
1806 | { | |
1807 | int r; | |
1808 | sector_t metadata_dev_size; | |
1809 | char b[BDEVNAME_SIZE]; | |
1810 | ||
1811 | if (!at_least_one_arg(as, error)) | |
1812 | return -EINVAL; | |
1813 | ||
1814 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1815 | &ca->metadata_dev); | |
1816 | if (r) { | |
1817 | *error = "Error opening metadata device"; | |
1818 | return r; | |
1819 | } | |
1820 | ||
1821 | metadata_dev_size = get_dev_size(ca->metadata_dev); | |
1822 | if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING) | |
1823 | DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", | |
1824 | bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS); | |
1825 | ||
1826 | return 0; | |
1827 | } | |
1828 | ||
1829 | static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1830 | char **error) | |
1831 | { | |
1832 | int r; | |
1833 | ||
1834 | if (!at_least_one_arg(as, error)) | |
1835 | return -EINVAL; | |
1836 | ||
1837 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1838 | &ca->cache_dev); | |
1839 | if (r) { | |
1840 | *error = "Error opening cache device"; | |
1841 | return r; | |
1842 | } | |
1843 | ca->cache_sectors = get_dev_size(ca->cache_dev); | |
1844 | ||
1845 | return 0; | |
1846 | } | |
1847 | ||
1848 | static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, | |
1849 | char **error) | |
1850 | { | |
1851 | int r; | |
1852 | ||
1853 | if (!at_least_one_arg(as, error)) | |
1854 | return -EINVAL; | |
1855 | ||
1856 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
1857 | &ca->origin_dev); | |
1858 | if (r) { | |
1859 | *error = "Error opening origin device"; | |
1860 | return r; | |
1861 | } | |
1862 | ||
1863 | ca->origin_sectors = get_dev_size(ca->origin_dev); | |
1864 | if (ca->ti->len > ca->origin_sectors) { | |
1865 | *error = "Device size larger than cached device"; | |
1866 | return -EINVAL; | |
1867 | } | |
1868 | ||
1869 | return 0; | |
1870 | } | |
1871 | ||
1872 | static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, | |
1873 | char **error) | |
1874 | { | |
05473044 | 1875 | unsigned long block_size; |
c6b4fcba JT |
1876 | |
1877 | if (!at_least_one_arg(as, error)) | |
1878 | return -EINVAL; | |
1879 | ||
05473044 MS |
1880 | if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size || |
1881 | block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || | |
1882 | block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || | |
1883 | block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { | |
c6b4fcba JT |
1884 | *error = "Invalid data block size"; |
1885 | return -EINVAL; | |
1886 | } | |
1887 | ||
05473044 | 1888 | if (block_size > ca->cache_sectors) { |
c6b4fcba JT |
1889 | *error = "Data block size is larger than the cache device"; |
1890 | return -EINVAL; | |
1891 | } | |
1892 | ||
05473044 | 1893 | ca->block_size = block_size; |
c6b4fcba JT |
1894 | |
1895 | return 0; | |
1896 | } | |
1897 | ||
1898 | static void init_features(struct cache_features *cf) | |
1899 | { | |
1900 | cf->mode = CM_WRITE; | |
2ee57d58 | 1901 | cf->io_mode = CM_IO_WRITEBACK; |
c6b4fcba JT |
1902 | } |
1903 | ||
1904 | static int parse_features(struct cache_args *ca, struct dm_arg_set *as, | |
1905 | char **error) | |
1906 | { | |
1907 | static struct dm_arg _args[] = { | |
1908 | {0, 1, "Invalid number of cache feature arguments"}, | |
1909 | }; | |
1910 | ||
1911 | int r; | |
1912 | unsigned argc; | |
1913 | const char *arg; | |
1914 | struct cache_features *cf = &ca->features; | |
1915 | ||
1916 | init_features(cf); | |
1917 | ||
1918 | r = dm_read_arg_group(_args, as, &argc, error); | |
1919 | if (r) | |
1920 | return -EINVAL; | |
1921 | ||
1922 | while (argc--) { | |
1923 | arg = dm_shift_arg(as); | |
1924 | ||
1925 | if (!strcasecmp(arg, "writeback")) | |
2ee57d58 | 1926 | cf->io_mode = CM_IO_WRITEBACK; |
c6b4fcba JT |
1927 | |
1928 | else if (!strcasecmp(arg, "writethrough")) | |
2ee57d58 JT |
1929 | cf->io_mode = CM_IO_WRITETHROUGH; |
1930 | ||
1931 | else if (!strcasecmp(arg, "passthrough")) | |
1932 | cf->io_mode = CM_IO_PASSTHROUGH; | |
c6b4fcba JT |
1933 | |
1934 | else { | |
1935 | *error = "Unrecognised cache feature requested"; | |
1936 | return -EINVAL; | |
1937 | } | |
1938 | } | |
1939 | ||
1940 | return 0; | |
1941 | } | |
1942 | ||
1943 | static int parse_policy(struct cache_args *ca, struct dm_arg_set *as, | |
1944 | char **error) | |
1945 | { | |
1946 | static struct dm_arg _args[] = { | |
1947 | {0, 1024, "Invalid number of policy arguments"}, | |
1948 | }; | |
1949 | ||
1950 | int r; | |
1951 | ||
1952 | if (!at_least_one_arg(as, error)) | |
1953 | return -EINVAL; | |
1954 | ||
1955 | ca->policy_name = dm_shift_arg(as); | |
1956 | ||
1957 | r = dm_read_arg_group(_args, as, &ca->policy_argc, error); | |
1958 | if (r) | |
1959 | return -EINVAL; | |
1960 | ||
1961 | ca->policy_argv = (const char **)as->argv; | |
1962 | dm_consume_args(as, ca->policy_argc); | |
1963 | ||
1964 | return 0; | |
1965 | } | |
1966 | ||
1967 | static int parse_cache_args(struct cache_args *ca, int argc, char **argv, | |
1968 | char **error) | |
1969 | { | |
1970 | int r; | |
1971 | struct dm_arg_set as; | |
1972 | ||
1973 | as.argc = argc; | |
1974 | as.argv = argv; | |
1975 | ||
1976 | r = parse_metadata_dev(ca, &as, error); | |
1977 | if (r) | |
1978 | return r; | |
1979 | ||
1980 | r = parse_cache_dev(ca, &as, error); | |
1981 | if (r) | |
1982 | return r; | |
1983 | ||
1984 | r = parse_origin_dev(ca, &as, error); | |
1985 | if (r) | |
1986 | return r; | |
1987 | ||
1988 | r = parse_block_size(ca, &as, error); | |
1989 | if (r) | |
1990 | return r; | |
1991 | ||
1992 | r = parse_features(ca, &as, error); | |
1993 | if (r) | |
1994 | return r; | |
1995 | ||
1996 | r = parse_policy(ca, &as, error); | |
1997 | if (r) | |
1998 | return r; | |
1999 | ||
2000 | return 0; | |
2001 | } | |
2002 | ||
2003 | /*----------------------------------------------------------------*/ | |
2004 | ||
2005 | static struct kmem_cache *migration_cache; | |
2006 | ||
2c73c471 AK |
2007 | #define NOT_CORE_OPTION 1 |
2008 | ||
2f14f4b5 | 2009 | static int process_config_option(struct cache *cache, const char *key, const char *value) |
2c73c471 AK |
2010 | { |
2011 | unsigned long tmp; | |
2012 | ||
2f14f4b5 JT |
2013 | if (!strcasecmp(key, "migration_threshold")) { |
2014 | if (kstrtoul(value, 10, &tmp)) | |
2c73c471 AK |
2015 | return -EINVAL; |
2016 | ||
2017 | cache->migration_threshold = tmp; | |
2018 | return 0; | |
2019 | } | |
2020 | ||
2021 | return NOT_CORE_OPTION; | |
2022 | } | |
2023 | ||
2f14f4b5 JT |
2024 | static int set_config_value(struct cache *cache, const char *key, const char *value) |
2025 | { | |
2026 | int r = process_config_option(cache, key, value); | |
2027 | ||
2028 | if (r == NOT_CORE_OPTION) | |
2029 | r = policy_set_config_value(cache->policy, key, value); | |
2030 | ||
2031 | if (r) | |
2032 | DMWARN("bad config value for %s: %s", key, value); | |
2033 | ||
2034 | return r; | |
2035 | } | |
2036 | ||
2037 | static int set_config_values(struct cache *cache, int argc, const char **argv) | |
c6b4fcba JT |
2038 | { |
2039 | int r = 0; | |
2040 | ||
2041 | if (argc & 1) { | |
2042 | DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs."); | |
2043 | return -EINVAL; | |
2044 | } | |
2045 | ||
2046 | while (argc) { | |
2f14f4b5 JT |
2047 | r = set_config_value(cache, argv[0], argv[1]); |
2048 | if (r) | |
2049 | break; | |
c6b4fcba JT |
2050 | |
2051 | argc -= 2; | |
2052 | argv += 2; | |
2053 | } | |
2054 | ||
2055 | return r; | |
2056 | } | |
2057 | ||
2058 | static int create_cache_policy(struct cache *cache, struct cache_args *ca, | |
2059 | char **error) | |
2060 | { | |
4cb3e1db MP |
2061 | struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name, |
2062 | cache->cache_size, | |
2063 | cache->origin_sectors, | |
2064 | cache->sectors_per_block); | |
2065 | if (IS_ERR(p)) { | |
c6b4fcba | 2066 | *error = "Error creating cache's policy"; |
4cb3e1db | 2067 | return PTR_ERR(p); |
c6b4fcba | 2068 | } |
4cb3e1db | 2069 | cache->policy = p; |
c6b4fcba | 2070 | |
2f14f4b5 | 2071 | return 0; |
c6b4fcba JT |
2072 | } |
2073 | ||
2074 | /* | |
2075 | * We want the discard block size to be a power of two, at least the size | |
2076 | * of the cache block size, and have no more than 2^14 discard blocks | |
2077 | * across the origin. | |
2078 | */ | |
2079 | #define MAX_DISCARD_BLOCKS (1 << 14) | |
2080 | ||
2081 | static bool too_many_discard_blocks(sector_t discard_block_size, | |
2082 | sector_t origin_size) | |
2083 | { | |
2084 | (void) sector_div(origin_size, discard_block_size); | |
2085 | ||
2086 | return origin_size > MAX_DISCARD_BLOCKS; | |
2087 | } | |
2088 | ||
2089 | static sector_t calculate_discard_block_size(sector_t cache_block_size, | |
2090 | sector_t origin_size) | |
2091 | { | |
2092 | sector_t discard_block_size; | |
2093 | ||
2094 | discard_block_size = roundup_pow_of_two(cache_block_size); | |
2095 | ||
2096 | if (origin_size) | |
2097 | while (too_many_discard_blocks(discard_block_size, origin_size)) | |
2098 | discard_block_size *= 2; | |
2099 | ||
2100 | return discard_block_size; | |
2101 | } | |
2102 | ||
f8350daf | 2103 | #define DEFAULT_MIGRATION_THRESHOLD 2048 |
c6b4fcba | 2104 | |
c6b4fcba JT |
2105 | static int cache_create(struct cache_args *ca, struct cache **result) |
2106 | { | |
2107 | int r = 0; | |
2108 | char **error = &ca->ti->error; | |
2109 | struct cache *cache; | |
2110 | struct dm_target *ti = ca->ti; | |
2111 | dm_block_t origin_blocks; | |
2112 | struct dm_cache_metadata *cmd; | |
2113 | bool may_format = ca->features.mode == CM_WRITE; | |
2114 | ||
2115 | cache = kzalloc(sizeof(*cache), GFP_KERNEL); | |
2116 | if (!cache) | |
2117 | return -ENOMEM; | |
2118 | ||
2119 | cache->ti = ca->ti; | |
2120 | ti->private = cache; | |
c6b4fcba JT |
2121 | ti->num_flush_bios = 2; |
2122 | ti->flush_supported = true; | |
2123 | ||
2124 | ti->num_discard_bios = 1; | |
2125 | ti->discards_supported = true; | |
2126 | ti->discard_zeroes_data_unsupported = true; | |
2127 | ||
8c5008fa | 2128 | cache->features = ca->features; |
19b0092e | 2129 | ti->per_bio_data_size = get_per_bio_data_size(cache); |
c6b4fcba | 2130 | |
c6b4fcba JT |
2131 | cache->callbacks.congested_fn = cache_is_congested; |
2132 | dm_table_add_target_callbacks(ti->table, &cache->callbacks); | |
2133 | ||
2134 | cache->metadata_dev = ca->metadata_dev; | |
2135 | cache->origin_dev = ca->origin_dev; | |
2136 | cache->cache_dev = ca->cache_dev; | |
2137 | ||
2138 | ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; | |
2139 | ||
2140 | /* FIXME: factor out this whole section */ | |
2141 | origin_blocks = cache->origin_sectors = ca->origin_sectors; | |
414dd67d | 2142 | origin_blocks = block_div(origin_blocks, ca->block_size); |
c6b4fcba JT |
2143 | cache->origin_blocks = to_oblock(origin_blocks); |
2144 | ||
2145 | cache->sectors_per_block = ca->block_size; | |
2146 | if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) { | |
2147 | r = -EINVAL; | |
2148 | goto bad; | |
2149 | } | |
2150 | ||
2151 | if (ca->block_size & (ca->block_size - 1)) { | |
2152 | dm_block_t cache_size = ca->cache_sectors; | |
2153 | ||
2154 | cache->sectors_per_block_shift = -1; | |
414dd67d | 2155 | cache_size = block_div(cache_size, ca->block_size); |
c6b4fcba JT |
2156 | cache->cache_size = to_cblock(cache_size); |
2157 | } else { | |
2158 | cache->sectors_per_block_shift = __ffs(ca->block_size); | |
2159 | cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift); | |
2160 | } | |
2161 | ||
2162 | r = create_cache_policy(cache, ca, error); | |
2163 | if (r) | |
2164 | goto bad; | |
2f14f4b5 | 2165 | |
c6b4fcba | 2166 | cache->policy_nr_args = ca->policy_argc; |
2f14f4b5 JT |
2167 | cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD; |
2168 | ||
2169 | r = set_config_values(cache, ca->policy_argc, ca->policy_argv); | |
2170 | if (r) { | |
2171 | *error = "Error setting cache policy's config values"; | |
2172 | goto bad; | |
2173 | } | |
c6b4fcba JT |
2174 | |
2175 | cmd = dm_cache_metadata_open(cache->metadata_dev->bdev, | |
2176 | ca->block_size, may_format, | |
2177 | dm_cache_policy_get_hint_size(cache->policy)); | |
2178 | if (IS_ERR(cmd)) { | |
2179 | *error = "Error creating metadata object"; | |
2180 | r = PTR_ERR(cmd); | |
2181 | goto bad; | |
2182 | } | |
2183 | cache->cmd = cmd; | |
2184 | ||
2ee57d58 JT |
2185 | if (passthrough_mode(&cache->features)) { |
2186 | bool all_clean; | |
2187 | ||
2188 | r = dm_cache_metadata_all_clean(cache->cmd, &all_clean); | |
2189 | if (r) { | |
2190 | *error = "dm_cache_metadata_all_clean() failed"; | |
2191 | goto bad; | |
2192 | } | |
2193 | ||
2194 | if (!all_clean) { | |
2195 | *error = "Cannot enter passthrough mode unless all blocks are clean"; | |
2196 | r = -EINVAL; | |
2197 | goto bad; | |
2198 | } | |
2199 | } | |
2200 | ||
c6b4fcba JT |
2201 | spin_lock_init(&cache->lock); |
2202 | bio_list_init(&cache->deferred_bios); | |
2203 | bio_list_init(&cache->deferred_flush_bios); | |
e2e74d61 | 2204 | bio_list_init(&cache->deferred_writethrough_bios); |
c6b4fcba JT |
2205 | INIT_LIST_HEAD(&cache->quiesced_migrations); |
2206 | INIT_LIST_HEAD(&cache->completed_migrations); | |
2207 | INIT_LIST_HEAD(&cache->need_commit_migrations); | |
c6b4fcba JT |
2208 | atomic_set(&cache->nr_migrations, 0); |
2209 | init_waitqueue_head(&cache->migration_wait); | |
2210 | ||
66cb1910 | 2211 | init_waitqueue_head(&cache->quiescing_wait); |
238f8363 | 2212 | atomic_set(&cache->quiescing, 0); |
66cb1910 JT |
2213 | atomic_set(&cache->quiescing_ack, 0); |
2214 | ||
fa4d683a | 2215 | r = -ENOMEM; |
c6b4fcba JT |
2216 | cache->nr_dirty = 0; |
2217 | cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size)); | |
2218 | if (!cache->dirty_bitset) { | |
2219 | *error = "could not allocate dirty bitset"; | |
2220 | goto bad; | |
2221 | } | |
2222 | clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size)); | |
2223 | ||
2224 | cache->discard_block_size = | |
2225 | calculate_discard_block_size(cache->sectors_per_block, | |
2226 | cache->origin_sectors); | |
2227 | cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks); | |
2228 | cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks)); | |
2229 | if (!cache->discard_bitset) { | |
2230 | *error = "could not allocate discard bitset"; | |
2231 | goto bad; | |
2232 | } | |
2233 | clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); | |
2234 | ||
2235 | cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); | |
2236 | if (IS_ERR(cache->copier)) { | |
2237 | *error = "could not create kcopyd client"; | |
2238 | r = PTR_ERR(cache->copier); | |
2239 | goto bad; | |
2240 | } | |
2241 | ||
2242 | cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); | |
2243 | if (!cache->wq) { | |
2244 | *error = "could not create workqueue for metadata object"; | |
2245 | goto bad; | |
2246 | } | |
2247 | INIT_WORK(&cache->worker, do_worker); | |
2248 | INIT_DELAYED_WORK(&cache->waker, do_waker); | |
2249 | cache->last_commit_jiffies = jiffies; | |
2250 | ||
2251 | cache->prison = dm_bio_prison_create(PRISON_CELLS); | |
2252 | if (!cache->prison) { | |
2253 | *error = "could not create bio prison"; | |
2254 | goto bad; | |
2255 | } | |
2256 | ||
2257 | cache->all_io_ds = dm_deferred_set_create(); | |
2258 | if (!cache->all_io_ds) { | |
2259 | *error = "could not create all_io deferred set"; | |
2260 | goto bad; | |
2261 | } | |
2262 | ||
2263 | cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE, | |
2264 | migration_cache); | |
2265 | if (!cache->migration_pool) { | |
2266 | *error = "Error creating cache's migration mempool"; | |
2267 | goto bad; | |
2268 | } | |
2269 | ||
2270 | cache->next_migration = NULL; | |
2271 | ||
2272 | cache->need_tick_bio = true; | |
2273 | cache->sized = false; | |
c6b4fcba JT |
2274 | cache->commit_requested = false; |
2275 | cache->loaded_mappings = false; | |
2276 | cache->loaded_discards = false; | |
2277 | ||
2278 | load_stats(cache); | |
2279 | ||
2280 | atomic_set(&cache->stats.demotion, 0); | |
2281 | atomic_set(&cache->stats.promotion, 0); | |
2282 | atomic_set(&cache->stats.copies_avoided, 0); | |
2283 | atomic_set(&cache->stats.cache_cell_clash, 0); | |
2284 | atomic_set(&cache->stats.commit_count, 0); | |
2285 | atomic_set(&cache->stats.discard_count, 0); | |
2286 | ||
2287 | *result = cache; | |
2288 | return 0; | |
2289 | ||
2290 | bad: | |
2291 | destroy(cache); | |
2292 | return r; | |
2293 | } | |
2294 | ||
2295 | static int copy_ctr_args(struct cache *cache, int argc, const char **argv) | |
2296 | { | |
2297 | unsigned i; | |
2298 | const char **copy; | |
2299 | ||
2300 | copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL); | |
2301 | if (!copy) | |
2302 | return -ENOMEM; | |
2303 | for (i = 0; i < argc; i++) { | |
2304 | copy[i] = kstrdup(argv[i], GFP_KERNEL); | |
2305 | if (!copy[i]) { | |
2306 | while (i--) | |
2307 | kfree(copy[i]); | |
2308 | kfree(copy); | |
2309 | return -ENOMEM; | |
2310 | } | |
2311 | } | |
2312 | ||
2313 | cache->nr_ctr_args = argc; | |
2314 | cache->ctr_args = copy; | |
2315 | ||
2316 | return 0; | |
2317 | } | |
2318 | ||
2319 | static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
2320 | { | |
2321 | int r = -EINVAL; | |
2322 | struct cache_args *ca; | |
2323 | struct cache *cache = NULL; | |
2324 | ||
2325 | ca = kzalloc(sizeof(*ca), GFP_KERNEL); | |
2326 | if (!ca) { | |
2327 | ti->error = "Error allocating memory for cache"; | |
2328 | return -ENOMEM; | |
2329 | } | |
2330 | ca->ti = ti; | |
2331 | ||
2332 | r = parse_cache_args(ca, argc, argv, &ti->error); | |
2333 | if (r) | |
2334 | goto out; | |
2335 | ||
2336 | r = cache_create(ca, &cache); | |
617a0b89 HM |
2337 | if (r) |
2338 | goto out; | |
c6b4fcba JT |
2339 | |
2340 | r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3); | |
2341 | if (r) { | |
2342 | destroy(cache); | |
2343 | goto out; | |
2344 | } | |
2345 | ||
2346 | ti->private = cache; | |
2347 | ||
2348 | out: | |
2349 | destroy_cache_args(ca); | |
2350 | return r; | |
2351 | } | |
2352 | ||
c6b4fcba JT |
2353 | static int cache_map(struct dm_target *ti, struct bio *bio) |
2354 | { | |
2355 | struct cache *cache = ti->private; | |
2356 | ||
2357 | int r; | |
2358 | dm_oblock_t block = get_bio_block(cache, bio); | |
19b0092e | 2359 | size_t pb_data_size = get_per_bio_data_size(cache); |
c6b4fcba JT |
2360 | bool can_migrate = false; |
2361 | bool discarded_block; | |
2362 | struct dm_bio_prison_cell *cell; | |
2363 | struct policy_result lookup_result; | |
2364 | struct per_bio_data *pb; | |
2365 | ||
2366 | if (from_oblock(block) > from_oblock(cache->origin_blocks)) { | |
2367 | /* | |
2368 | * This can only occur if the io goes to a partial block at | |
2369 | * the end of the origin device. We don't cache these. | |
2370 | * Just remap to the origin and carry on. | |
2371 | */ | |
2372 | remap_to_origin_clear_discard(cache, bio, block); | |
2373 | return DM_MAPIO_REMAPPED; | |
2374 | } | |
2375 | ||
19b0092e | 2376 | pb = init_per_bio_data(bio, pb_data_size); |
c6b4fcba JT |
2377 | |
2378 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) { | |
2379 | defer_bio(cache, bio); | |
2380 | return DM_MAPIO_SUBMITTED; | |
2381 | } | |
2382 | ||
2383 | /* | |
2384 | * Check to see if that block is currently migrating. | |
2385 | */ | |
2386 | cell = alloc_prison_cell(cache); | |
2387 | if (!cell) { | |
2388 | defer_bio(cache, bio); | |
2389 | return DM_MAPIO_SUBMITTED; | |
2390 | } | |
2391 | ||
2392 | r = bio_detain(cache, block, bio, cell, | |
2393 | (cell_free_fn) free_prison_cell, | |
2394 | cache, &cell); | |
2395 | if (r) { | |
2396 | if (r < 0) | |
2397 | defer_bio(cache, bio); | |
2398 | ||
2399 | return DM_MAPIO_SUBMITTED; | |
2400 | } | |
2401 | ||
2402 | discarded_block = is_discarded_oblock(cache, block); | |
2403 | ||
2404 | r = policy_map(cache->policy, block, false, can_migrate, discarded_block, | |
2405 | bio, &lookup_result); | |
2406 | if (r == -EWOULDBLOCK) { | |
2407 | cell_defer(cache, cell, true); | |
2408 | return DM_MAPIO_SUBMITTED; | |
2409 | ||
2410 | } else if (r) { | |
2411 | DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r); | |
2412 | bio_io_error(bio); | |
2413 | return DM_MAPIO_SUBMITTED; | |
2414 | } | |
2415 | ||
2ee57d58 | 2416 | r = DM_MAPIO_REMAPPED; |
c6b4fcba JT |
2417 | switch (lookup_result.op) { |
2418 | case POLICY_HIT: | |
2ee57d58 JT |
2419 | if (passthrough_mode(&cache->features)) { |
2420 | if (bio_data_dir(bio) == WRITE) { | |
2421 | /* | |
2422 | * We need to invalidate this block, so | |
2423 | * defer for the worker thread. | |
2424 | */ | |
2425 | cell_defer(cache, cell, true); | |
2426 | r = DM_MAPIO_SUBMITTED; | |
2427 | ||
2428 | } else { | |
2429 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
2430 | inc_miss_counter(cache, bio); | |
2431 | remap_to_origin_clear_discard(cache, bio, block); | |
2432 | ||
2433 | cell_defer(cache, cell, false); | |
2434 | } | |
c6b4fcba | 2435 | |
2ee57d58 JT |
2436 | } else { |
2437 | inc_hit_counter(cache, bio); | |
2438 | ||
2439 | if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) && | |
2440 | !is_dirty(cache, lookup_result.cblock)) | |
2441 | remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); | |
2442 | else | |
2443 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); | |
e2e74d61 | 2444 | |
2ee57d58 JT |
2445 | cell_defer(cache, cell, false); |
2446 | } | |
c6b4fcba JT |
2447 | break; |
2448 | ||
2449 | case POLICY_MISS: | |
2450 | inc_miss_counter(cache, bio); | |
2451 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
2452 | ||
2453 | if (pb->req_nr != 0) { | |
2454 | /* | |
2455 | * This is a duplicate writethrough io that is no | |
2456 | * longer needed because the block has been demoted. | |
2457 | */ | |
2458 | bio_endio(bio, 0); | |
2459 | cell_defer(cache, cell, false); | |
2460 | return DM_MAPIO_SUBMITTED; | |
2461 | } else { | |
2462 | remap_to_origin_clear_discard(cache, bio, block); | |
2463 | cell_defer(cache, cell, false); | |
2464 | } | |
2465 | break; | |
2466 | ||
2467 | default: | |
2468 | DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__, | |
2469 | (unsigned) lookup_result.op); | |
2470 | bio_io_error(bio); | |
2ee57d58 | 2471 | r = DM_MAPIO_SUBMITTED; |
c6b4fcba JT |
2472 | } |
2473 | ||
2ee57d58 | 2474 | return r; |
c6b4fcba JT |
2475 | } |
2476 | ||
2477 | static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) | |
2478 | { | |
2479 | struct cache *cache = ti->private; | |
2480 | unsigned long flags; | |
19b0092e MS |
2481 | size_t pb_data_size = get_per_bio_data_size(cache); |
2482 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
2483 | |
2484 | if (pb->tick) { | |
2485 | policy_tick(cache->policy); | |
2486 | ||
2487 | spin_lock_irqsave(&cache->lock, flags); | |
2488 | cache->need_tick_bio = true; | |
2489 | spin_unlock_irqrestore(&cache->lock, flags); | |
2490 | } | |
2491 | ||
2492 | check_for_quiesced_migrations(cache, pb); | |
2493 | ||
2494 | return 0; | |
2495 | } | |
2496 | ||
2497 | static int write_dirty_bitset(struct cache *cache) | |
2498 | { | |
2499 | unsigned i, r; | |
2500 | ||
2501 | for (i = 0; i < from_cblock(cache->cache_size); i++) { | |
2502 | r = dm_cache_set_dirty(cache->cmd, to_cblock(i), | |
2503 | is_dirty(cache, to_cblock(i))); | |
2504 | if (r) | |
2505 | return r; | |
2506 | } | |
2507 | ||
2508 | return 0; | |
2509 | } | |
2510 | ||
2511 | static int write_discard_bitset(struct cache *cache) | |
2512 | { | |
2513 | unsigned i, r; | |
2514 | ||
2515 | r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size, | |
2516 | cache->discard_nr_blocks); | |
2517 | if (r) { | |
2518 | DMERR("could not resize on-disk discard bitset"); | |
2519 | return r; | |
2520 | } | |
2521 | ||
2522 | for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) { | |
2523 | r = dm_cache_set_discard(cache->cmd, to_dblock(i), | |
2524 | is_discarded(cache, to_dblock(i))); | |
2525 | if (r) | |
2526 | return r; | |
2527 | } | |
2528 | ||
2529 | return 0; | |
2530 | } | |
2531 | ||
2532 | static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, | |
2533 | uint32_t hint) | |
2534 | { | |
2535 | struct cache *cache = context; | |
2536 | return dm_cache_save_hint(cache->cmd, cblock, hint); | |
2537 | } | |
2538 | ||
2539 | static int write_hints(struct cache *cache) | |
2540 | { | |
2541 | int r; | |
2542 | ||
2543 | r = dm_cache_begin_hints(cache->cmd, cache->policy); | |
2544 | if (r) { | |
2545 | DMERR("dm_cache_begin_hints failed"); | |
2546 | return r; | |
2547 | } | |
2548 | ||
2549 | r = policy_walk_mappings(cache->policy, save_hint, cache); | |
2550 | if (r) | |
2551 | DMERR("policy_walk_mappings failed"); | |
2552 | ||
2553 | return r; | |
2554 | } | |
2555 | ||
2556 | /* | |
2557 | * returns true on success | |
2558 | */ | |
2559 | static bool sync_metadata(struct cache *cache) | |
2560 | { | |
2561 | int r1, r2, r3, r4; | |
2562 | ||
2563 | r1 = write_dirty_bitset(cache); | |
2564 | if (r1) | |
2565 | DMERR("could not write dirty bitset"); | |
2566 | ||
2567 | r2 = write_discard_bitset(cache); | |
2568 | if (r2) | |
2569 | DMERR("could not write discard bitset"); | |
2570 | ||
2571 | save_stats(cache); | |
2572 | ||
2573 | r3 = write_hints(cache); | |
2574 | if (r3) | |
2575 | DMERR("could not write hints"); | |
2576 | ||
2577 | /* | |
2578 | * If writing the above metadata failed, we still commit, but don't | |
2579 | * set the clean shutdown flag. This will effectively force every | |
2580 | * dirty bit to be set on reload. | |
2581 | */ | |
2582 | r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3); | |
2583 | if (r4) | |
2584 | DMERR("could not write cache metadata. Data loss may occur."); | |
2585 | ||
2586 | return !r1 && !r2 && !r3 && !r4; | |
2587 | } | |
2588 | ||
2589 | static void cache_postsuspend(struct dm_target *ti) | |
2590 | { | |
2591 | struct cache *cache = ti->private; | |
2592 | ||
2593 | start_quiescing(cache); | |
2594 | wait_for_migrations(cache); | |
2595 | stop_worker(cache); | |
2596 | requeue_deferred_io(cache); | |
2597 | stop_quiescing(cache); | |
2598 | ||
2599 | (void) sync_metadata(cache); | |
2600 | } | |
2601 | ||
2602 | static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, | |
2603 | bool dirty, uint32_t hint, bool hint_valid) | |
2604 | { | |
2605 | int r; | |
2606 | struct cache *cache = context; | |
2607 | ||
2608 | r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid); | |
2609 | if (r) | |
2610 | return r; | |
2611 | ||
2612 | if (dirty) | |
2613 | set_dirty(cache, oblock, cblock); | |
2614 | else | |
2615 | clear_dirty(cache, oblock, cblock); | |
2616 | ||
2617 | return 0; | |
2618 | } | |
2619 | ||
2620 | static int load_discard(void *context, sector_t discard_block_size, | |
2621 | dm_dblock_t dblock, bool discard) | |
2622 | { | |
2623 | struct cache *cache = context; | |
2624 | ||
2625 | /* FIXME: handle mis-matched block size */ | |
2626 | ||
2627 | if (discard) | |
2628 | set_discard(cache, dblock); | |
2629 | else | |
2630 | clear_discard(cache, dblock); | |
2631 | ||
2632 | return 0; | |
2633 | } | |
2634 | ||
f494a9c6 JT |
2635 | static dm_cblock_t get_cache_dev_size(struct cache *cache) |
2636 | { | |
2637 | sector_t size = get_dev_size(cache->cache_dev); | |
2638 | (void) sector_div(size, cache->sectors_per_block); | |
2639 | return to_cblock(size); | |
2640 | } | |
2641 | ||
2642 | static bool can_resize(struct cache *cache, dm_cblock_t new_size) | |
2643 | { | |
2644 | if (from_cblock(new_size) > from_cblock(cache->cache_size)) | |
2645 | return true; | |
2646 | ||
2647 | /* | |
2648 | * We can't drop a dirty block when shrinking the cache. | |
2649 | */ | |
2650 | while (from_cblock(new_size) < from_cblock(cache->cache_size)) { | |
2651 | new_size = to_cblock(from_cblock(new_size) + 1); | |
2652 | if (is_dirty(cache, new_size)) { | |
2653 | DMERR("unable to shrink cache; cache block %llu is dirty", | |
2654 | (unsigned long long) from_cblock(new_size)); | |
2655 | return false; | |
2656 | } | |
2657 | } | |
2658 | ||
2659 | return true; | |
2660 | } | |
2661 | ||
2662 | static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size) | |
2663 | { | |
2664 | int r; | |
2665 | ||
2666 | r = dm_cache_resize(cache->cmd, cache->cache_size); | |
2667 | if (r) { | |
2668 | DMERR("could not resize cache metadata"); | |
2669 | return r; | |
2670 | } | |
2671 | ||
2672 | cache->cache_size = new_size; | |
2673 | ||
2674 | return 0; | |
2675 | } | |
2676 | ||
c6b4fcba JT |
2677 | static int cache_preresume(struct dm_target *ti) |
2678 | { | |
2679 | int r = 0; | |
2680 | struct cache *cache = ti->private; | |
f494a9c6 | 2681 | dm_cblock_t csize = get_cache_dev_size(cache); |
c6b4fcba JT |
2682 | |
2683 | /* | |
2684 | * Check to see if the cache has resized. | |
2685 | */ | |
f494a9c6 JT |
2686 | if (!cache->sized) { |
2687 | r = resize_cache_dev(cache, csize); | |
2688 | if (r) | |
c6b4fcba | 2689 | return r; |
c6b4fcba JT |
2690 | |
2691 | cache->sized = true; | |
f494a9c6 JT |
2692 | |
2693 | } else if (csize != cache->cache_size) { | |
2694 | if (!can_resize(cache, csize)) | |
2695 | return -EINVAL; | |
2696 | ||
2697 | r = resize_cache_dev(cache, csize); | |
2698 | if (r) | |
2699 | return r; | |
c6b4fcba JT |
2700 | } |
2701 | ||
2702 | if (!cache->loaded_mappings) { | |
ea2dd8c1 | 2703 | r = dm_cache_load_mappings(cache->cmd, cache->policy, |
c6b4fcba JT |
2704 | load_mapping, cache); |
2705 | if (r) { | |
2706 | DMERR("could not load cache mappings"); | |
2707 | return r; | |
2708 | } | |
2709 | ||
2710 | cache->loaded_mappings = true; | |
2711 | } | |
2712 | ||
2713 | if (!cache->loaded_discards) { | |
2714 | r = dm_cache_load_discards(cache->cmd, load_discard, cache); | |
2715 | if (r) { | |
2716 | DMERR("could not load origin discards"); | |
2717 | return r; | |
2718 | } | |
2719 | ||
2720 | cache->loaded_discards = true; | |
2721 | } | |
2722 | ||
2723 | return r; | |
2724 | } | |
2725 | ||
2726 | static void cache_resume(struct dm_target *ti) | |
2727 | { | |
2728 | struct cache *cache = ti->private; | |
2729 | ||
2730 | cache->need_tick_bio = true; | |
2731 | do_waker(&cache->waker.work); | |
2732 | } | |
2733 | ||
2734 | /* | |
2735 | * Status format: | |
2736 | * | |
2737 | * <#used metadata blocks>/<#total metadata blocks> | |
2738 | * <#read hits> <#read misses> <#write hits> <#write misses> | |
2739 | * <#demotions> <#promotions> <#blocks in cache> <#dirty> | |
2740 | * <#features> <features>* | |
2741 | * <#core args> <core args> | |
2742 | * <#policy args> <policy args>* | |
2743 | */ | |
2744 | static void cache_status(struct dm_target *ti, status_type_t type, | |
2745 | unsigned status_flags, char *result, unsigned maxlen) | |
2746 | { | |
2747 | int r = 0; | |
2748 | unsigned i; | |
2749 | ssize_t sz = 0; | |
2750 | dm_block_t nr_free_blocks_metadata = 0; | |
2751 | dm_block_t nr_blocks_metadata = 0; | |
2752 | char buf[BDEVNAME_SIZE]; | |
2753 | struct cache *cache = ti->private; | |
2754 | dm_cblock_t residency; | |
2755 | ||
2756 | switch (type) { | |
2757 | case STATUSTYPE_INFO: | |
2758 | /* Commit to ensure statistics aren't out-of-date */ | |
2759 | if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) { | |
2760 | r = dm_cache_commit(cache->cmd, false); | |
2761 | if (r) | |
2762 | DMERR("could not commit metadata for accurate status"); | |
2763 | } | |
2764 | ||
2765 | r = dm_cache_get_free_metadata_block_count(cache->cmd, | |
2766 | &nr_free_blocks_metadata); | |
2767 | if (r) { | |
2768 | DMERR("could not get metadata free block count"); | |
2769 | goto err; | |
2770 | } | |
2771 | ||
2772 | r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata); | |
2773 | if (r) { | |
2774 | DMERR("could not get metadata device size"); | |
2775 | goto err; | |
2776 | } | |
2777 | ||
2778 | residency = policy_residency(cache->policy); | |
2779 | ||
2780 | DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ", | |
2781 | (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), | |
2782 | (unsigned long long)nr_blocks_metadata, | |
2783 | (unsigned) atomic_read(&cache->stats.read_hit), | |
2784 | (unsigned) atomic_read(&cache->stats.read_miss), | |
2785 | (unsigned) atomic_read(&cache->stats.write_hit), | |
2786 | (unsigned) atomic_read(&cache->stats.write_miss), | |
2787 | (unsigned) atomic_read(&cache->stats.demotion), | |
2788 | (unsigned) atomic_read(&cache->stats.promotion), | |
2789 | (unsigned long long) from_cblock(residency), | |
2790 | cache->nr_dirty); | |
2791 | ||
2ee57d58 | 2792 | if (writethrough_mode(&cache->features)) |
c6b4fcba | 2793 | DMEMIT("1 writethrough "); |
2ee57d58 JT |
2794 | |
2795 | else if (passthrough_mode(&cache->features)) | |
2796 | DMEMIT("1 passthrough "); | |
2797 | ||
2798 | else if (writeback_mode(&cache->features)) | |
2799 | DMEMIT("1 writeback "); | |
2800 | ||
2801 | else { | |
2802 | DMERR("internal error: unknown io mode: %d", (int) cache->features.io_mode); | |
2803 | goto err; | |
2804 | } | |
c6b4fcba JT |
2805 | |
2806 | DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold); | |
2807 | if (sz < maxlen) { | |
2808 | r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz); | |
2809 | if (r) | |
2810 | DMERR("policy_emit_config_values returned %d", r); | |
2811 | } | |
2812 | ||
2813 | break; | |
2814 | ||
2815 | case STATUSTYPE_TABLE: | |
2816 | format_dev_t(buf, cache->metadata_dev->bdev->bd_dev); | |
2817 | DMEMIT("%s ", buf); | |
2818 | format_dev_t(buf, cache->cache_dev->bdev->bd_dev); | |
2819 | DMEMIT("%s ", buf); | |
2820 | format_dev_t(buf, cache->origin_dev->bdev->bd_dev); | |
2821 | DMEMIT("%s", buf); | |
2822 | ||
2823 | for (i = 0; i < cache->nr_ctr_args - 1; i++) | |
2824 | DMEMIT(" %s", cache->ctr_args[i]); | |
2825 | if (cache->nr_ctr_args) | |
2826 | DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]); | |
2827 | } | |
2828 | ||
2829 | return; | |
2830 | ||
2831 | err: | |
2832 | DMEMIT("Error"); | |
2833 | } | |
2834 | ||
c6b4fcba JT |
2835 | /* |
2836 | * Supports <key> <value>. | |
2837 | * | |
2838 | * The key migration_threshold is supported by the cache target core. | |
2839 | */ | |
2840 | static int cache_message(struct dm_target *ti, unsigned argc, char **argv) | |
2841 | { | |
c6b4fcba JT |
2842 | struct cache *cache = ti->private; |
2843 | ||
2844 | if (argc != 2) | |
2845 | return -EINVAL; | |
2846 | ||
2f14f4b5 | 2847 | return set_config_value(cache, argv[0], argv[1]); |
c6b4fcba JT |
2848 | } |
2849 | ||
2850 | static int cache_iterate_devices(struct dm_target *ti, | |
2851 | iterate_devices_callout_fn fn, void *data) | |
2852 | { | |
2853 | int r = 0; | |
2854 | struct cache *cache = ti->private; | |
2855 | ||
2856 | r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data); | |
2857 | if (!r) | |
2858 | r = fn(ti, cache->origin_dev, 0, ti->len, data); | |
2859 | ||
2860 | return r; | |
2861 | } | |
2862 | ||
2863 | /* | |
2864 | * We assume I/O is going to the origin (which is the volume | |
2865 | * more likely to have restrictions e.g. by being striped). | |
2866 | * (Looking up the exact location of the data would be expensive | |
2867 | * and could always be out of date by the time the bio is submitted.) | |
2868 | */ | |
2869 | static int cache_bvec_merge(struct dm_target *ti, | |
2870 | struct bvec_merge_data *bvm, | |
2871 | struct bio_vec *biovec, int max_size) | |
2872 | { | |
2873 | struct cache *cache = ti->private; | |
2874 | struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev); | |
2875 | ||
2876 | if (!q->merge_bvec_fn) | |
2877 | return max_size; | |
2878 | ||
2879 | bvm->bi_bdev = cache->origin_dev->bdev; | |
2880 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
2881 | } | |
2882 | ||
2883 | static void set_discard_limits(struct cache *cache, struct queue_limits *limits) | |
2884 | { | |
2885 | /* | |
2886 | * FIXME: these limits may be incompatible with the cache device | |
2887 | */ | |
2888 | limits->max_discard_sectors = cache->discard_block_size * 1024; | |
2889 | limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT; | |
2890 | } | |
2891 | ||
2892 | static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
2893 | { | |
2894 | struct cache *cache = ti->private; | |
f6109372 | 2895 | uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; |
c6b4fcba | 2896 | |
f6109372 MS |
2897 | /* |
2898 | * If the system-determined stacked limits are compatible with the | |
2899 | * cache's blocksize (io_opt is a factor) do not override them. | |
2900 | */ | |
2901 | if (io_opt_sectors < cache->sectors_per_block || | |
2902 | do_div(io_opt_sectors, cache->sectors_per_block)) { | |
2903 | blk_limits_io_min(limits, 0); | |
2904 | blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT); | |
2905 | } | |
c6b4fcba JT |
2906 | set_discard_limits(cache, limits); |
2907 | } | |
2908 | ||
2909 | /*----------------------------------------------------------------*/ | |
2910 | ||
2911 | static struct target_type cache_target = { | |
2912 | .name = "cache", | |
2ee57d58 | 2913 | .version = {1, 2, 0}, |
c6b4fcba JT |
2914 | .module = THIS_MODULE, |
2915 | .ctr = cache_ctr, | |
2916 | .dtr = cache_dtr, | |
2917 | .map = cache_map, | |
2918 | .end_io = cache_end_io, | |
2919 | .postsuspend = cache_postsuspend, | |
2920 | .preresume = cache_preresume, | |
2921 | .resume = cache_resume, | |
2922 | .status = cache_status, | |
2923 | .message = cache_message, | |
2924 | .iterate_devices = cache_iterate_devices, | |
2925 | .merge = cache_bvec_merge, | |
2926 | .io_hints = cache_io_hints, | |
2927 | }; | |
2928 | ||
2929 | static int __init dm_cache_init(void) | |
2930 | { | |
2931 | int r; | |
2932 | ||
2933 | r = dm_register_target(&cache_target); | |
2934 | if (r) { | |
2935 | DMERR("cache target registration failed: %d", r); | |
2936 | return r; | |
2937 | } | |
2938 | ||
2939 | migration_cache = KMEM_CACHE(dm_cache_migration, 0); | |
2940 | if (!migration_cache) { | |
2941 | dm_unregister_target(&cache_target); | |
2942 | return -ENOMEM; | |
2943 | } | |
2944 | ||
2945 | return 0; | |
2946 | } | |
2947 | ||
2948 | static void __exit dm_cache_exit(void) | |
2949 | { | |
2950 | dm_unregister_target(&cache_target); | |
2951 | kmem_cache_destroy(migration_cache); | |
2952 | } | |
2953 | ||
2954 | module_init(dm_cache_init); | |
2955 | module_exit(dm_cache_exit); | |
2956 | ||
2957 | MODULE_DESCRIPTION(DM_NAME " cache target"); | |
2958 | MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); | |
2959 | MODULE_LICENSE("GPL"); |