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> | |
0f30af98 | 14 | #include <linux/jiffies.h> |
c6b4fcba JT |
15 | #include <linux/init.h> |
16 | #include <linux/mempool.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/vmalloc.h> | |
20 | ||
21 | #define DM_MSG_PREFIX "cache" | |
22 | ||
23 | DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle, | |
24 | "A percentage of time allocated for copying to and/or from cache"); | |
25 | ||
26 | /*----------------------------------------------------------------*/ | |
27 | ||
28 | /* | |
29 | * Glossary: | |
30 | * | |
31 | * oblock: index of an origin block | |
32 | * cblock: index of a cache block | |
33 | * promotion: movement of a block from origin to cache | |
34 | * demotion: movement of a block from cache to origin | |
35 | * migration: movement of a block between the origin and cache device, | |
36 | * either direction | |
37 | */ | |
38 | ||
39 | /*----------------------------------------------------------------*/ | |
40 | ||
41 | static size_t bitset_size_in_bytes(unsigned nr_entries) | |
42 | { | |
43 | return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG); | |
44 | } | |
45 | ||
46 | static unsigned long *alloc_bitset(unsigned nr_entries) | |
47 | { | |
48 | size_t s = bitset_size_in_bytes(nr_entries); | |
49 | return vzalloc(s); | |
50 | } | |
51 | ||
52 | static void clear_bitset(void *bitset, unsigned nr_entries) | |
53 | { | |
54 | size_t s = bitset_size_in_bytes(nr_entries); | |
55 | memset(bitset, 0, s); | |
56 | } | |
57 | ||
58 | static void free_bitset(unsigned long *bits) | |
59 | { | |
60 | vfree(bits); | |
61 | } | |
62 | ||
63 | /*----------------------------------------------------------------*/ | |
64 | ||
c9d28d5d JT |
65 | /* |
66 | * There are a couple of places where we let a bio run, but want to do some | |
67 | * work before calling its endio function. We do this by temporarily | |
68 | * changing the endio fn. | |
69 | */ | |
70 | struct dm_hook_info { | |
71 | bio_end_io_t *bi_end_io; | |
72 | void *bi_private; | |
73 | }; | |
74 | ||
75 | static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio, | |
76 | bio_end_io_t *bi_end_io, void *bi_private) | |
77 | { | |
78 | h->bi_end_io = bio->bi_end_io; | |
79 | h->bi_private = bio->bi_private; | |
80 | ||
81 | bio->bi_end_io = bi_end_io; | |
82 | bio->bi_private = bi_private; | |
83 | } | |
84 | ||
85 | static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio) | |
86 | { | |
87 | bio->bi_end_io = h->bi_end_io; | |
88 | bio->bi_private = h->bi_private; | |
8d307269 MS |
89 | |
90 | /* | |
91 | * Must bump bi_remaining to allow bio to complete with | |
92 | * restored bi_end_io. | |
93 | */ | |
94 | atomic_inc(&bio->bi_remaining); | |
c9d28d5d JT |
95 | } |
96 | ||
97 | /*----------------------------------------------------------------*/ | |
98 | ||
c6b4fcba JT |
99 | #define MIGRATION_POOL_SIZE 128 |
100 | #define COMMIT_PERIOD HZ | |
101 | #define MIGRATION_COUNT_WINDOW 10 | |
102 | ||
103 | /* | |
05473044 MS |
104 | * The block size of the device holding cache data must be |
105 | * between 32KB and 1GB. | |
c6b4fcba JT |
106 | */ |
107 | #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) | |
05473044 | 108 | #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) |
c6b4fcba JT |
109 | |
110 | /* | |
111 | * FIXME: the cache is read/write for the time being. | |
112 | */ | |
2ee57d58 | 113 | enum cache_metadata_mode { |
c6b4fcba JT |
114 | CM_WRITE, /* metadata may be changed */ |
115 | CM_READ_ONLY, /* metadata may not be changed */ | |
116 | }; | |
117 | ||
2ee57d58 JT |
118 | enum cache_io_mode { |
119 | /* | |
120 | * Data is written to cached blocks only. These blocks are marked | |
121 | * dirty. If you lose the cache device you will lose data. | |
122 | * Potential performance increase for both reads and writes. | |
123 | */ | |
124 | CM_IO_WRITEBACK, | |
125 | ||
126 | /* | |
127 | * Data is written to both cache and origin. Blocks are never | |
128 | * dirty. Potential performance benfit for reads only. | |
129 | */ | |
130 | CM_IO_WRITETHROUGH, | |
131 | ||
132 | /* | |
133 | * A degraded mode useful for various cache coherency situations | |
134 | * (eg, rolling back snapshots). Reads and writes always go to the | |
135 | * origin. If a write goes to a cached oblock, then the cache | |
136 | * block is invalidated. | |
137 | */ | |
138 | CM_IO_PASSTHROUGH | |
139 | }; | |
140 | ||
c6b4fcba | 141 | struct cache_features { |
2ee57d58 JT |
142 | enum cache_metadata_mode mode; |
143 | enum cache_io_mode io_mode; | |
c6b4fcba JT |
144 | }; |
145 | ||
146 | struct cache_stats { | |
147 | atomic_t read_hit; | |
148 | atomic_t read_miss; | |
149 | atomic_t write_hit; | |
150 | atomic_t write_miss; | |
151 | atomic_t demotion; | |
152 | atomic_t promotion; | |
153 | atomic_t copies_avoided; | |
154 | atomic_t cache_cell_clash; | |
155 | atomic_t commit_count; | |
156 | atomic_t discard_count; | |
157 | }; | |
158 | ||
65790ff9 JT |
159 | /* |
160 | * Defines a range of cblocks, begin to (end - 1) are in the range. end is | |
161 | * the one-past-the-end value. | |
162 | */ | |
163 | struct cblock_range { | |
164 | dm_cblock_t begin; | |
165 | dm_cblock_t end; | |
166 | }; | |
167 | ||
168 | struct invalidation_request { | |
169 | struct list_head list; | |
170 | struct cblock_range *cblocks; | |
171 | ||
172 | atomic_t complete; | |
173 | int err; | |
174 | ||
175 | wait_queue_head_t result_wait; | |
176 | }; | |
177 | ||
c6b4fcba JT |
178 | struct cache { |
179 | struct dm_target *ti; | |
180 | struct dm_target_callbacks callbacks; | |
181 | ||
c9ec5d7c MS |
182 | struct dm_cache_metadata *cmd; |
183 | ||
c6b4fcba JT |
184 | /* |
185 | * Metadata is written to this device. | |
186 | */ | |
187 | struct dm_dev *metadata_dev; | |
188 | ||
189 | /* | |
190 | * The slower of the two data devices. Typically a spindle. | |
191 | */ | |
192 | struct dm_dev *origin_dev; | |
193 | ||
194 | /* | |
195 | * The faster of the two data devices. Typically an SSD. | |
196 | */ | |
197 | struct dm_dev *cache_dev; | |
198 | ||
c6b4fcba JT |
199 | /* |
200 | * Size of the origin device in _complete_ blocks and native sectors. | |
201 | */ | |
202 | dm_oblock_t origin_blocks; | |
203 | sector_t origin_sectors; | |
204 | ||
205 | /* | |
206 | * Size of the cache device in blocks. | |
207 | */ | |
208 | dm_cblock_t cache_size; | |
209 | ||
210 | /* | |
211 | * Fields for converting from sectors to blocks. | |
212 | */ | |
213 | uint32_t sectors_per_block; | |
214 | int sectors_per_block_shift; | |
215 | ||
c6b4fcba JT |
216 | spinlock_t lock; |
217 | struct bio_list deferred_bios; | |
218 | struct bio_list deferred_flush_bios; | |
e2e74d61 | 219 | struct bio_list deferred_writethrough_bios; |
c6b4fcba JT |
220 | struct list_head quiesced_migrations; |
221 | struct list_head completed_migrations; | |
222 | struct list_head need_commit_migrations; | |
223 | sector_t migration_threshold; | |
c6b4fcba | 224 | wait_queue_head_t migration_wait; |
a59db676 JT |
225 | atomic_t nr_allocated_migrations; |
226 | ||
227 | /* | |
228 | * The number of in flight migrations that are performing | |
229 | * background io. eg, promotion, writeback. | |
230 | */ | |
231 | atomic_t nr_io_migrations; | |
c6b4fcba | 232 | |
66cb1910 | 233 | wait_queue_head_t quiescing_wait; |
238f8363 | 234 | atomic_t quiescing; |
66cb1910 JT |
235 | atomic_t quiescing_ack; |
236 | ||
c6b4fcba JT |
237 | /* |
238 | * cache_size entries, dirty if set | |
239 | */ | |
44fa816b | 240 | atomic_t nr_dirty; |
c6b4fcba JT |
241 | unsigned long *dirty_bitset; |
242 | ||
243 | /* | |
244 | * origin_blocks entries, discarded if set. | |
245 | */ | |
1bad9bc4 | 246 | dm_dblock_t discard_nr_blocks; |
c6b4fcba | 247 | unsigned long *discard_bitset; |
08b18451 | 248 | uint32_t discard_block_size; /* a power of 2 times sectors per block */ |
c9ec5d7c MS |
249 | |
250 | /* | |
251 | * Rather than reconstructing the table line for the status we just | |
252 | * save it and regurgitate. | |
253 | */ | |
254 | unsigned nr_ctr_args; | |
255 | const char **ctr_args; | |
c6b4fcba JT |
256 | |
257 | struct dm_kcopyd_client *copier; | |
258 | struct workqueue_struct *wq; | |
259 | struct work_struct worker; | |
260 | ||
261 | struct delayed_work waker; | |
262 | unsigned long last_commit_jiffies; | |
263 | ||
264 | struct dm_bio_prison *prison; | |
265 | struct dm_deferred_set *all_io_ds; | |
266 | ||
267 | mempool_t *migration_pool; | |
c6b4fcba JT |
268 | |
269 | struct dm_cache_policy *policy; | |
270 | unsigned policy_nr_args; | |
271 | ||
272 | bool need_tick_bio:1; | |
273 | bool sized:1; | |
65790ff9 | 274 | bool invalidate:1; |
c6b4fcba JT |
275 | bool commit_requested:1; |
276 | bool loaded_mappings:1; | |
277 | bool loaded_discards:1; | |
278 | ||
c6b4fcba | 279 | /* |
c9ec5d7c | 280 | * Cache features such as write-through. |
c6b4fcba | 281 | */ |
c9ec5d7c MS |
282 | struct cache_features features; |
283 | ||
284 | struct cache_stats stats; | |
65790ff9 JT |
285 | |
286 | /* | |
287 | * Invalidation fields. | |
288 | */ | |
289 | spinlock_t invalidation_lock; | |
290 | struct list_head invalidation_requests; | |
c6b4fcba JT |
291 | }; |
292 | ||
293 | struct per_bio_data { | |
294 | bool tick:1; | |
295 | unsigned req_nr:2; | |
296 | struct dm_deferred_entry *all_io_entry; | |
c6eda5e8 | 297 | struct dm_hook_info hook_info; |
e2e74d61 | 298 | |
19b0092e MS |
299 | /* |
300 | * writethrough fields. These MUST remain at the end of this | |
301 | * structure and the 'cache' member must be the first as it | |
aeed1420 | 302 | * is used to determine the offset of the writethrough fields. |
19b0092e | 303 | */ |
e2e74d61 JT |
304 | struct cache *cache; |
305 | dm_cblock_t cblock; | |
b844fe69 | 306 | struct dm_bio_details bio_details; |
c6b4fcba JT |
307 | }; |
308 | ||
309 | struct dm_cache_migration { | |
310 | struct list_head list; | |
311 | struct cache *cache; | |
312 | ||
313 | unsigned long start_jiffies; | |
314 | dm_oblock_t old_oblock; | |
315 | dm_oblock_t new_oblock; | |
316 | dm_cblock_t cblock; | |
317 | ||
318 | bool err:1; | |
7ae34e77 | 319 | bool discard:1; |
c6b4fcba JT |
320 | bool writeback:1; |
321 | bool demote:1; | |
322 | bool promote:1; | |
c9d28d5d | 323 | bool requeue_holder:1; |
65790ff9 | 324 | bool invalidate:1; |
c6b4fcba JT |
325 | |
326 | struct dm_bio_prison_cell *old_ocell; | |
327 | struct dm_bio_prison_cell *new_ocell; | |
328 | }; | |
329 | ||
330 | /* | |
331 | * Processing a bio in the worker thread may require these memory | |
332 | * allocations. We prealloc to avoid deadlocks (the same worker thread | |
333 | * frees them back to the mempool). | |
334 | */ | |
335 | struct prealloc { | |
336 | struct dm_cache_migration *mg; | |
337 | struct dm_bio_prison_cell *cell1; | |
338 | struct dm_bio_prison_cell *cell2; | |
339 | }; | |
340 | ||
341 | static void wake_worker(struct cache *cache) | |
342 | { | |
343 | queue_work(cache->wq, &cache->worker); | |
344 | } | |
345 | ||
346 | /*----------------------------------------------------------------*/ | |
347 | ||
348 | static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache) | |
349 | { | |
350 | /* FIXME: change to use a local slab. */ | |
351 | return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT); | |
352 | } | |
353 | ||
354 | static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell) | |
355 | { | |
356 | dm_bio_prison_free_cell(cache->prison, cell); | |
357 | } | |
358 | ||
a59db676 JT |
359 | static struct dm_cache_migration *alloc_migration(struct cache *cache) |
360 | { | |
361 | struct dm_cache_migration *mg; | |
362 | ||
363 | mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT); | |
364 | if (mg) { | |
365 | mg->cache = cache; | |
366 | atomic_inc(&mg->cache->nr_allocated_migrations); | |
367 | } | |
368 | ||
369 | return mg; | |
370 | } | |
371 | ||
372 | static void free_migration(struct dm_cache_migration *mg) | |
373 | { | |
374 | if (atomic_dec_and_test(&mg->cache->nr_allocated_migrations)) | |
375 | wake_up(&mg->cache->migration_wait); | |
376 | ||
377 | mempool_free(mg, mg->cache->migration_pool); | |
378 | } | |
379 | ||
c6b4fcba JT |
380 | static int prealloc_data_structs(struct cache *cache, struct prealloc *p) |
381 | { | |
382 | if (!p->mg) { | |
a59db676 | 383 | p->mg = alloc_migration(cache); |
c6b4fcba JT |
384 | if (!p->mg) |
385 | return -ENOMEM; | |
386 | } | |
387 | ||
388 | if (!p->cell1) { | |
389 | p->cell1 = alloc_prison_cell(cache); | |
390 | if (!p->cell1) | |
391 | return -ENOMEM; | |
392 | } | |
393 | ||
394 | if (!p->cell2) { | |
395 | p->cell2 = alloc_prison_cell(cache); | |
396 | if (!p->cell2) | |
397 | return -ENOMEM; | |
398 | } | |
399 | ||
400 | return 0; | |
401 | } | |
402 | ||
403 | static void prealloc_free_structs(struct cache *cache, struct prealloc *p) | |
404 | { | |
405 | if (p->cell2) | |
406 | free_prison_cell(cache, p->cell2); | |
407 | ||
408 | if (p->cell1) | |
409 | free_prison_cell(cache, p->cell1); | |
410 | ||
411 | if (p->mg) | |
a59db676 | 412 | free_migration(p->mg); |
c6b4fcba JT |
413 | } |
414 | ||
415 | static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p) | |
416 | { | |
417 | struct dm_cache_migration *mg = p->mg; | |
418 | ||
419 | BUG_ON(!mg); | |
420 | p->mg = NULL; | |
421 | ||
422 | return mg; | |
423 | } | |
424 | ||
425 | /* | |
426 | * You must have a cell within the prealloc struct to return. If not this | |
427 | * function will BUG() rather than returning NULL. | |
428 | */ | |
429 | static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p) | |
430 | { | |
431 | struct dm_bio_prison_cell *r = NULL; | |
432 | ||
433 | if (p->cell1) { | |
434 | r = p->cell1; | |
435 | p->cell1 = NULL; | |
436 | ||
437 | } else if (p->cell2) { | |
438 | r = p->cell2; | |
439 | p->cell2 = NULL; | |
440 | } else | |
441 | BUG(); | |
442 | ||
443 | return r; | |
444 | } | |
445 | ||
446 | /* | |
447 | * You can't have more than two cells in a prealloc struct. BUG() will be | |
448 | * called if you try and overfill. | |
449 | */ | |
450 | static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell) | |
451 | { | |
452 | if (!p->cell2) | |
453 | p->cell2 = cell; | |
454 | ||
455 | else if (!p->cell1) | |
456 | p->cell1 = cell; | |
457 | ||
458 | else | |
459 | BUG(); | |
460 | } | |
461 | ||
462 | /*----------------------------------------------------------------*/ | |
463 | ||
7ae34e77 | 464 | static void build_key(dm_oblock_t begin, dm_oblock_t end, struct dm_cell_key *key) |
c6b4fcba JT |
465 | { |
466 | key->virtual = 0; | |
467 | key->dev = 0; | |
7ae34e77 JT |
468 | key->block_begin = from_oblock(begin); |
469 | key->block_end = from_oblock(end); | |
c6b4fcba JT |
470 | } |
471 | ||
472 | /* | |
473 | * The caller hands in a preallocated cell, and a free function for it. | |
474 | * The cell will be freed if there's an error, or if it wasn't used because | |
475 | * a cell with that key already exists. | |
476 | */ | |
477 | typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell); | |
478 | ||
7ae34e77 JT |
479 | static int bio_detain_range(struct cache *cache, dm_oblock_t oblock_begin, dm_oblock_t oblock_end, |
480 | struct bio *bio, struct dm_bio_prison_cell *cell_prealloc, | |
481 | cell_free_fn free_fn, void *free_context, | |
482 | struct dm_bio_prison_cell **cell_result) | |
c6b4fcba JT |
483 | { |
484 | int r; | |
485 | struct dm_cell_key key; | |
486 | ||
7ae34e77 | 487 | build_key(oblock_begin, oblock_end, &key); |
c6b4fcba JT |
488 | r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result); |
489 | if (r) | |
490 | free_fn(free_context, cell_prealloc); | |
491 | ||
492 | return r; | |
493 | } | |
494 | ||
7ae34e77 JT |
495 | static int bio_detain(struct cache *cache, dm_oblock_t oblock, |
496 | struct bio *bio, struct dm_bio_prison_cell *cell_prealloc, | |
497 | cell_free_fn free_fn, void *free_context, | |
498 | struct dm_bio_prison_cell **cell_result) | |
499 | { | |
500 | dm_oblock_t end = to_oblock(from_oblock(oblock) + 1ULL); | |
501 | return bio_detain_range(cache, oblock, end, bio, | |
502 | cell_prealloc, free_fn, free_context, cell_result); | |
503 | } | |
504 | ||
c6b4fcba JT |
505 | static int get_cell(struct cache *cache, |
506 | dm_oblock_t oblock, | |
507 | struct prealloc *structs, | |
508 | struct dm_bio_prison_cell **cell_result) | |
509 | { | |
510 | int r; | |
511 | struct dm_cell_key key; | |
512 | struct dm_bio_prison_cell *cell_prealloc; | |
513 | ||
514 | cell_prealloc = prealloc_get_cell(structs); | |
515 | ||
7ae34e77 | 516 | build_key(oblock, to_oblock(from_oblock(oblock) + 1ULL), &key); |
c6b4fcba JT |
517 | r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result); |
518 | if (r) | |
519 | prealloc_put_cell(structs, cell_prealloc); | |
520 | ||
521 | return r; | |
522 | } | |
523 | ||
aeed1420 | 524 | /*----------------------------------------------------------------*/ |
c6b4fcba JT |
525 | |
526 | static bool is_dirty(struct cache *cache, dm_cblock_t b) | |
527 | { | |
528 | return test_bit(from_cblock(b), cache->dirty_bitset); | |
529 | } | |
530 | ||
531 | static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | |
532 | { | |
533 | if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
44fa816b | 534 | atomic_inc(&cache->nr_dirty); |
c6b4fcba JT |
535 | policy_set_dirty(cache->policy, oblock); |
536 | } | |
537 | } | |
538 | ||
539 | static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) | |
540 | { | |
541 | if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) { | |
542 | policy_clear_dirty(cache->policy, oblock); | |
44fa816b | 543 | if (atomic_dec_return(&cache->nr_dirty) == 0) |
c6b4fcba JT |
544 | dm_table_event(cache->ti->table); |
545 | } | |
546 | } | |
547 | ||
548 | /*----------------------------------------------------------------*/ | |
aeed1420 | 549 | |
c6b4fcba JT |
550 | static bool block_size_is_power_of_two(struct cache *cache) |
551 | { | |
552 | return cache->sectors_per_block_shift >= 0; | |
553 | } | |
554 | ||
43aeaa29 MP |
555 | /* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */ |
556 | #if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6 | |
557 | __always_inline | |
558 | #endif | |
414dd67d JT |
559 | static dm_block_t block_div(dm_block_t b, uint32_t n) |
560 | { | |
561 | do_div(b, n); | |
562 | ||
563 | return b; | |
564 | } | |
565 | ||
7ae34e77 | 566 | static dm_block_t oblocks_per_dblock(struct cache *cache) |
1bad9bc4 | 567 | { |
7ae34e77 | 568 | dm_block_t oblocks = cache->discard_block_size; |
1bad9bc4 | 569 | |
7ae34e77 JT |
570 | if (block_size_is_power_of_two(cache)) |
571 | oblocks >>= cache->sectors_per_block_shift; | |
1bad9bc4 | 572 | else |
7ae34e77 | 573 | oblocks = block_div(oblocks, cache->sectors_per_block); |
1bad9bc4 | 574 | |
7ae34e77 JT |
575 | return oblocks; |
576 | } | |
577 | ||
578 | static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) | |
579 | { | |
580 | return to_dblock(block_div(from_oblock(oblock), | |
581 | oblocks_per_dblock(cache))); | |
582 | } | |
1bad9bc4 | 583 | |
7ae34e77 JT |
584 | static dm_oblock_t dblock_to_oblock(struct cache *cache, dm_dblock_t dblock) |
585 | { | |
586 | return to_oblock(from_dblock(dblock) * oblocks_per_dblock(cache)); | |
1bad9bc4 JT |
587 | } |
588 | ||
589 | static void set_discard(struct cache *cache, dm_dblock_t b) | |
c6b4fcba JT |
590 | { |
591 | unsigned long flags; | |
592 | ||
7ae34e77 | 593 | BUG_ON(from_dblock(b) >= from_dblock(cache->discard_nr_blocks)); |
c6b4fcba JT |
594 | atomic_inc(&cache->stats.discard_count); |
595 | ||
596 | spin_lock_irqsave(&cache->lock, flags); | |
1bad9bc4 | 597 | set_bit(from_dblock(b), cache->discard_bitset); |
c6b4fcba JT |
598 | spin_unlock_irqrestore(&cache->lock, flags); |
599 | } | |
600 | ||
1bad9bc4 | 601 | static void clear_discard(struct cache *cache, dm_dblock_t b) |
c6b4fcba JT |
602 | { |
603 | unsigned long flags; | |
604 | ||
605 | spin_lock_irqsave(&cache->lock, flags); | |
1bad9bc4 | 606 | clear_bit(from_dblock(b), cache->discard_bitset); |
c6b4fcba JT |
607 | spin_unlock_irqrestore(&cache->lock, flags); |
608 | } | |
609 | ||
1bad9bc4 | 610 | static bool is_discarded(struct cache *cache, dm_dblock_t b) |
c6b4fcba JT |
611 | { |
612 | int r; | |
613 | unsigned long flags; | |
614 | ||
615 | spin_lock_irqsave(&cache->lock, flags); | |
1bad9bc4 | 616 | r = test_bit(from_dblock(b), cache->discard_bitset); |
c6b4fcba JT |
617 | spin_unlock_irqrestore(&cache->lock, flags); |
618 | ||
619 | return r; | |
620 | } | |
621 | ||
622 | static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) | |
623 | { | |
624 | int r; | |
625 | unsigned long flags; | |
626 | ||
627 | spin_lock_irqsave(&cache->lock, flags); | |
1bad9bc4 JT |
628 | r = test_bit(from_dblock(oblock_to_dblock(cache, b)), |
629 | cache->discard_bitset); | |
c6b4fcba JT |
630 | spin_unlock_irqrestore(&cache->lock, flags); |
631 | ||
632 | return r; | |
633 | } | |
634 | ||
635 | /*----------------------------------------------------------------*/ | |
636 | ||
637 | static void load_stats(struct cache *cache) | |
638 | { | |
639 | struct dm_cache_statistics stats; | |
640 | ||
641 | dm_cache_metadata_get_stats(cache->cmd, &stats); | |
642 | atomic_set(&cache->stats.read_hit, stats.read_hits); | |
643 | atomic_set(&cache->stats.read_miss, stats.read_misses); | |
644 | atomic_set(&cache->stats.write_hit, stats.write_hits); | |
645 | atomic_set(&cache->stats.write_miss, stats.write_misses); | |
646 | } | |
647 | ||
648 | static void save_stats(struct cache *cache) | |
649 | { | |
650 | struct dm_cache_statistics stats; | |
651 | ||
652 | stats.read_hits = atomic_read(&cache->stats.read_hit); | |
653 | stats.read_misses = atomic_read(&cache->stats.read_miss); | |
654 | stats.write_hits = atomic_read(&cache->stats.write_hit); | |
655 | stats.write_misses = atomic_read(&cache->stats.write_miss); | |
656 | ||
657 | dm_cache_metadata_set_stats(cache->cmd, &stats); | |
658 | } | |
659 | ||
660 | /*---------------------------------------------------------------- | |
661 | * Per bio data | |
662 | *--------------------------------------------------------------*/ | |
19b0092e MS |
663 | |
664 | /* | |
665 | * If using writeback, leave out struct per_bio_data's writethrough fields. | |
666 | */ | |
667 | #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) | |
668 | #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) | |
669 | ||
2ee57d58 JT |
670 | static bool writethrough_mode(struct cache_features *f) |
671 | { | |
672 | return f->io_mode == CM_IO_WRITETHROUGH; | |
673 | } | |
674 | ||
675 | static bool writeback_mode(struct cache_features *f) | |
676 | { | |
677 | return f->io_mode == CM_IO_WRITEBACK; | |
678 | } | |
679 | ||
680 | static bool passthrough_mode(struct cache_features *f) | |
681 | { | |
682 | return f->io_mode == CM_IO_PASSTHROUGH; | |
683 | } | |
684 | ||
19b0092e MS |
685 | static size_t get_per_bio_data_size(struct cache *cache) |
686 | { | |
2ee57d58 | 687 | return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; |
19b0092e MS |
688 | } |
689 | ||
690 | static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size) | |
c6b4fcba | 691 | { |
19b0092e | 692 | struct per_bio_data *pb = dm_per_bio_data(bio, data_size); |
c6b4fcba JT |
693 | BUG_ON(!pb); |
694 | return pb; | |
695 | } | |
696 | ||
19b0092e | 697 | static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size) |
c6b4fcba | 698 | { |
19b0092e | 699 | struct per_bio_data *pb = get_per_bio_data(bio, data_size); |
c6b4fcba JT |
700 | |
701 | pb->tick = false; | |
702 | pb->req_nr = dm_bio_get_target_bio_nr(bio); | |
703 | pb->all_io_entry = NULL; | |
704 | ||
705 | return pb; | |
706 | } | |
707 | ||
708 | /*---------------------------------------------------------------- | |
709 | * Remapping | |
710 | *--------------------------------------------------------------*/ | |
711 | static void remap_to_origin(struct cache *cache, struct bio *bio) | |
712 | { | |
713 | bio->bi_bdev = cache->origin_dev->bdev; | |
714 | } | |
715 | ||
716 | static void remap_to_cache(struct cache *cache, struct bio *bio, | |
717 | dm_cblock_t cblock) | |
718 | { | |
4f024f37 | 719 | sector_t bi_sector = bio->bi_iter.bi_sector; |
e0d849fa | 720 | sector_t block = from_cblock(cblock); |
c6b4fcba JT |
721 | |
722 | bio->bi_bdev = cache->cache_dev->bdev; | |
723 | if (!block_size_is_power_of_two(cache)) | |
4f024f37 | 724 | bio->bi_iter.bi_sector = |
e0d849fa | 725 | (block * cache->sectors_per_block) + |
4f024f37 | 726 | sector_div(bi_sector, cache->sectors_per_block); |
c6b4fcba | 727 | else |
4f024f37 | 728 | bio->bi_iter.bi_sector = |
e0d849fa | 729 | (block << cache->sectors_per_block_shift) | |
4f024f37 | 730 | (bi_sector & (cache->sectors_per_block - 1)); |
c6b4fcba JT |
731 | } |
732 | ||
733 | static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) | |
734 | { | |
735 | unsigned long flags; | |
19b0092e MS |
736 | size_t pb_data_size = get_per_bio_data_size(cache); |
737 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
738 | |
739 | spin_lock_irqsave(&cache->lock, flags); | |
740 | if (cache->need_tick_bio && | |
741 | !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) { | |
742 | pb->tick = true; | |
743 | cache->need_tick_bio = false; | |
744 | } | |
745 | spin_unlock_irqrestore(&cache->lock, flags); | |
746 | } | |
747 | ||
748 | static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, | |
749 | dm_oblock_t oblock) | |
750 | { | |
751 | check_if_tick_bio_needed(cache, bio); | |
752 | remap_to_origin(cache, bio); | |
753 | if (bio_data_dir(bio) == WRITE) | |
1bad9bc4 | 754 | clear_discard(cache, oblock_to_dblock(cache, oblock)); |
c6b4fcba JT |
755 | } |
756 | ||
757 | static void remap_to_cache_dirty(struct cache *cache, struct bio *bio, | |
758 | dm_oblock_t oblock, dm_cblock_t cblock) | |
759 | { | |
f8e5f01a | 760 | check_if_tick_bio_needed(cache, bio); |
c6b4fcba JT |
761 | remap_to_cache(cache, bio, cblock); |
762 | if (bio_data_dir(bio) == WRITE) { | |
763 | set_dirty(cache, oblock, cblock); | |
1bad9bc4 | 764 | clear_discard(cache, oblock_to_dblock(cache, oblock)); |
c6b4fcba JT |
765 | } |
766 | } | |
767 | ||
768 | static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) | |
769 | { | |
4f024f37 | 770 | sector_t block_nr = bio->bi_iter.bi_sector; |
c6b4fcba JT |
771 | |
772 | if (!block_size_is_power_of_two(cache)) | |
773 | (void) sector_div(block_nr, cache->sectors_per_block); | |
774 | else | |
775 | block_nr >>= cache->sectors_per_block_shift; | |
776 | ||
777 | return to_oblock(block_nr); | |
778 | } | |
779 | ||
780 | static int bio_triggers_commit(struct cache *cache, struct bio *bio) | |
781 | { | |
782 | return bio->bi_rw & (REQ_FLUSH | REQ_FUA); | |
783 | } | |
784 | ||
8c081b52 JT |
785 | /* |
786 | * You must increment the deferred set whilst the prison cell is held. To | |
787 | * encourage this, we ask for 'cell' to be passed in. | |
788 | */ | |
789 | static void inc_ds(struct cache *cache, struct bio *bio, | |
790 | struct dm_bio_prison_cell *cell) | |
791 | { | |
792 | size_t pb_data_size = get_per_bio_data_size(cache); | |
793 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
794 | ||
795 | BUG_ON(!cell); | |
796 | BUG_ON(pb->all_io_entry); | |
797 | ||
798 | pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); | |
799 | } | |
800 | ||
c6b4fcba JT |
801 | static void issue(struct cache *cache, struct bio *bio) |
802 | { | |
803 | unsigned long flags; | |
804 | ||
805 | if (!bio_triggers_commit(cache, bio)) { | |
806 | generic_make_request(bio); | |
807 | return; | |
808 | } | |
809 | ||
810 | /* | |
811 | * Batch together any bios that trigger commits and then issue a | |
812 | * single commit for them in do_worker(). | |
813 | */ | |
814 | spin_lock_irqsave(&cache->lock, flags); | |
815 | cache->commit_requested = true; | |
816 | bio_list_add(&cache->deferred_flush_bios, bio); | |
817 | spin_unlock_irqrestore(&cache->lock, flags); | |
818 | } | |
819 | ||
8c081b52 JT |
820 | static void inc_and_issue(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell *cell) |
821 | { | |
822 | inc_ds(cache, bio, cell); | |
823 | issue(cache, bio); | |
824 | } | |
825 | ||
e2e74d61 JT |
826 | static void defer_writethrough_bio(struct cache *cache, struct bio *bio) |
827 | { | |
828 | unsigned long flags; | |
829 | ||
830 | spin_lock_irqsave(&cache->lock, flags); | |
831 | bio_list_add(&cache->deferred_writethrough_bios, bio); | |
832 | spin_unlock_irqrestore(&cache->lock, flags); | |
833 | ||
834 | wake_worker(cache); | |
835 | } | |
836 | ||
837 | static void writethrough_endio(struct bio *bio, int err) | |
838 | { | |
19b0092e | 839 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
c9d28d5d JT |
840 | |
841 | dm_unhook_bio(&pb->hook_info, bio); | |
e2e74d61 JT |
842 | |
843 | if (err) { | |
844 | bio_endio(bio, err); | |
845 | return; | |
846 | } | |
847 | ||
b844fe69 | 848 | dm_bio_restore(&pb->bio_details, bio); |
e2e74d61 JT |
849 | remap_to_cache(pb->cache, bio, pb->cblock); |
850 | ||
851 | /* | |
852 | * We can't issue this bio directly, since we're in interrupt | |
aeed1420 | 853 | * context. So it gets put on a bio list for processing by the |
e2e74d61 JT |
854 | * worker thread. |
855 | */ | |
856 | defer_writethrough_bio(pb->cache, bio); | |
857 | } | |
858 | ||
859 | /* | |
860 | * When running in writethrough mode we need to send writes to clean blocks | |
861 | * to both the cache and origin devices. In future we'd like to clone the | |
862 | * bio and send them in parallel, but for now we're doing them in | |
863 | * series as this is easier. | |
864 | */ | |
865 | static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, | |
866 | dm_oblock_t oblock, dm_cblock_t cblock) | |
867 | { | |
19b0092e | 868 | struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
e2e74d61 JT |
869 | |
870 | pb->cache = cache; | |
871 | pb->cblock = cblock; | |
c9d28d5d | 872 | dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL); |
b844fe69 | 873 | dm_bio_record(&pb->bio_details, bio); |
e2e74d61 JT |
874 | |
875 | remap_to_origin_clear_discard(pb->cache, bio, oblock); | |
876 | } | |
877 | ||
c6b4fcba JT |
878 | /*---------------------------------------------------------------- |
879 | * Migration processing | |
880 | * | |
881 | * Migration covers moving data from the origin device to the cache, or | |
882 | * vice versa. | |
883 | *--------------------------------------------------------------*/ | |
a59db676 | 884 | static void inc_io_migrations(struct cache *cache) |
c6b4fcba | 885 | { |
a59db676 | 886 | atomic_inc(&cache->nr_io_migrations); |
c6b4fcba JT |
887 | } |
888 | ||
a59db676 | 889 | static void dec_io_migrations(struct cache *cache) |
c6b4fcba | 890 | { |
a59db676 | 891 | atomic_dec(&cache->nr_io_migrations); |
c6b4fcba JT |
892 | } |
893 | ||
894 | static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | |
895 | bool holder) | |
896 | { | |
897 | (holder ? dm_cell_release : dm_cell_release_no_holder) | |
898 | (cache->prison, cell, &cache->deferred_bios); | |
899 | free_prison_cell(cache, cell); | |
900 | } | |
901 | ||
902 | static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, | |
903 | bool holder) | |
904 | { | |
905 | unsigned long flags; | |
906 | ||
907 | spin_lock_irqsave(&cache->lock, flags); | |
908 | __cell_defer(cache, cell, holder); | |
909 | spin_unlock_irqrestore(&cache->lock, flags); | |
910 | ||
911 | wake_worker(cache); | |
912 | } | |
913 | ||
a59db676 | 914 | static void free_io_migration(struct dm_cache_migration *mg) |
c6b4fcba | 915 | { |
a59db676 | 916 | dec_io_migrations(mg->cache); |
c6b4fcba JT |
917 | free_migration(mg); |
918 | } | |
919 | ||
920 | static void migration_failure(struct dm_cache_migration *mg) | |
921 | { | |
922 | struct cache *cache = mg->cache; | |
923 | ||
924 | if (mg->writeback) { | |
925 | DMWARN_LIMIT("writeback failed; couldn't copy block"); | |
926 | set_dirty(cache, mg->old_oblock, mg->cblock); | |
927 | cell_defer(cache, mg->old_ocell, false); | |
928 | ||
929 | } else if (mg->demote) { | |
930 | DMWARN_LIMIT("demotion failed; couldn't copy block"); | |
931 | policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); | |
932 | ||
80f659f3 | 933 | cell_defer(cache, mg->old_ocell, mg->promote ? false : true); |
c6b4fcba | 934 | if (mg->promote) |
80f659f3 | 935 | cell_defer(cache, mg->new_ocell, true); |
c6b4fcba JT |
936 | } else { |
937 | DMWARN_LIMIT("promotion failed; couldn't copy block"); | |
938 | policy_remove_mapping(cache->policy, mg->new_oblock); | |
80f659f3 | 939 | cell_defer(cache, mg->new_ocell, true); |
c6b4fcba JT |
940 | } |
941 | ||
a59db676 | 942 | free_io_migration(mg); |
c6b4fcba JT |
943 | } |
944 | ||
945 | static void migration_success_pre_commit(struct dm_cache_migration *mg) | |
946 | { | |
947 | unsigned long flags; | |
948 | struct cache *cache = mg->cache; | |
949 | ||
950 | if (mg->writeback) { | |
c6b4fcba | 951 | clear_dirty(cache, mg->old_oblock, mg->cblock); |
40aa978e | 952 | cell_defer(cache, mg->old_ocell, false); |
a59db676 | 953 | free_io_migration(mg); |
c6b4fcba JT |
954 | return; |
955 | ||
956 | } else if (mg->demote) { | |
957 | if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) { | |
958 | DMWARN_LIMIT("demotion failed; couldn't update on disk metadata"); | |
959 | policy_force_mapping(cache->policy, mg->new_oblock, | |
960 | mg->old_oblock); | |
961 | if (mg->promote) | |
962 | cell_defer(cache, mg->new_ocell, true); | |
a59db676 | 963 | free_io_migration(mg); |
c6b4fcba JT |
964 | return; |
965 | } | |
966 | } else { | |
967 | if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) { | |
968 | DMWARN_LIMIT("promotion failed; couldn't update on disk metadata"); | |
969 | policy_remove_mapping(cache->policy, mg->new_oblock); | |
a59db676 | 970 | free_io_migration(mg); |
c6b4fcba JT |
971 | return; |
972 | } | |
973 | } | |
974 | ||
975 | spin_lock_irqsave(&cache->lock, flags); | |
976 | list_add_tail(&mg->list, &cache->need_commit_migrations); | |
977 | cache->commit_requested = true; | |
978 | spin_unlock_irqrestore(&cache->lock, flags); | |
979 | } | |
980 | ||
981 | static void migration_success_post_commit(struct dm_cache_migration *mg) | |
982 | { | |
983 | unsigned long flags; | |
984 | struct cache *cache = mg->cache; | |
985 | ||
986 | if (mg->writeback) { | |
987 | DMWARN("writeback unexpectedly triggered commit"); | |
988 | return; | |
989 | ||
990 | } else if (mg->demote) { | |
80f659f3 | 991 | cell_defer(cache, mg->old_ocell, mg->promote ? false : true); |
c6b4fcba JT |
992 | |
993 | if (mg->promote) { | |
994 | mg->demote = false; | |
995 | ||
996 | spin_lock_irqsave(&cache->lock, flags); | |
997 | list_add_tail(&mg->list, &cache->quiesced_migrations); | |
998 | spin_unlock_irqrestore(&cache->lock, flags); | |
999 | ||
65790ff9 JT |
1000 | } else { |
1001 | if (mg->invalidate) | |
1002 | policy_remove_mapping(cache->policy, mg->old_oblock); | |
a59db676 | 1003 | free_io_migration(mg); |
65790ff9 | 1004 | } |
c6b4fcba JT |
1005 | |
1006 | } else { | |
1e32134a JT |
1007 | if (mg->requeue_holder) { |
1008 | clear_dirty(cache, mg->new_oblock, mg->cblock); | |
c9d28d5d | 1009 | cell_defer(cache, mg->new_ocell, true); |
1e32134a JT |
1010 | } else { |
1011 | /* | |
1012 | * The block was promoted via an overwrite, so it's dirty. | |
1013 | */ | |
1014 | set_dirty(cache, mg->new_oblock, mg->cblock); | |
c9d28d5d JT |
1015 | bio_endio(mg->new_ocell->holder, 0); |
1016 | cell_defer(cache, mg->new_ocell, false); | |
1017 | } | |
a59db676 | 1018 | free_io_migration(mg); |
c6b4fcba JT |
1019 | } |
1020 | } | |
1021 | ||
1022 | static void copy_complete(int read_err, unsigned long write_err, void *context) | |
1023 | { | |
1024 | unsigned long flags; | |
1025 | struct dm_cache_migration *mg = (struct dm_cache_migration *) context; | |
1026 | struct cache *cache = mg->cache; | |
1027 | ||
1028 | if (read_err || write_err) | |
1029 | mg->err = true; | |
1030 | ||
1031 | spin_lock_irqsave(&cache->lock, flags); | |
1032 | list_add_tail(&mg->list, &cache->completed_migrations); | |
1033 | spin_unlock_irqrestore(&cache->lock, flags); | |
1034 | ||
1035 | wake_worker(cache); | |
1036 | } | |
1037 | ||
7ae34e77 | 1038 | static void issue_copy(struct dm_cache_migration *mg) |
c6b4fcba JT |
1039 | { |
1040 | int r; | |
1041 | struct dm_io_region o_region, c_region; | |
1042 | struct cache *cache = mg->cache; | |
8b9d9666 | 1043 | sector_t cblock = from_cblock(mg->cblock); |
c6b4fcba JT |
1044 | |
1045 | o_region.bdev = cache->origin_dev->bdev; | |
1046 | o_region.count = cache->sectors_per_block; | |
1047 | ||
1048 | c_region.bdev = cache->cache_dev->bdev; | |
8b9d9666 | 1049 | c_region.sector = cblock * cache->sectors_per_block; |
c6b4fcba JT |
1050 | c_region.count = cache->sectors_per_block; |
1051 | ||
1052 | if (mg->writeback || mg->demote) { | |
1053 | /* demote */ | |
1054 | o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block; | |
1055 | r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg); | |
1056 | } else { | |
1057 | /* promote */ | |
1058 | o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block; | |
1059 | r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg); | |
1060 | } | |
1061 | ||
2c2263c9 HM |
1062 | if (r < 0) { |
1063 | DMERR_LIMIT("issuing migration failed"); | |
c6b4fcba | 1064 | migration_failure(mg); |
2c2263c9 | 1065 | } |
c6b4fcba JT |
1066 | } |
1067 | ||
c9d28d5d JT |
1068 | static void overwrite_endio(struct bio *bio, int err) |
1069 | { | |
1070 | struct dm_cache_migration *mg = bio->bi_private; | |
1071 | struct cache *cache = mg->cache; | |
1072 | size_t pb_data_size = get_per_bio_data_size(cache); | |
1073 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
1074 | unsigned long flags; | |
1075 | ||
80ae49aa MS |
1076 | dm_unhook_bio(&pb->hook_info, bio); |
1077 | ||
c9d28d5d JT |
1078 | if (err) |
1079 | mg->err = true; | |
1080 | ||
80ae49aa MS |
1081 | mg->requeue_holder = false; |
1082 | ||
c9d28d5d JT |
1083 | spin_lock_irqsave(&cache->lock, flags); |
1084 | list_add_tail(&mg->list, &cache->completed_migrations); | |
c9d28d5d JT |
1085 | spin_unlock_irqrestore(&cache->lock, flags); |
1086 | ||
1087 | wake_worker(cache); | |
1088 | } | |
1089 | ||
1090 | static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio) | |
1091 | { | |
1092 | size_t pb_data_size = get_per_bio_data_size(mg->cache); | |
1093 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
1094 | ||
1095 | dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg); | |
1096 | remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock); | |
8c081b52 JT |
1097 | |
1098 | /* | |
1099 | * No need to inc_ds() here, since the cell will be held for the | |
1100 | * duration of the io. | |
1101 | */ | |
c9d28d5d JT |
1102 | generic_make_request(bio); |
1103 | } | |
1104 | ||
1105 | static bool bio_writes_complete_block(struct cache *cache, struct bio *bio) | |
1106 | { | |
1107 | return (bio_data_dir(bio) == WRITE) && | |
4f024f37 | 1108 | (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT)); |
c9d28d5d JT |
1109 | } |
1110 | ||
c6b4fcba JT |
1111 | static void avoid_copy(struct dm_cache_migration *mg) |
1112 | { | |
1113 | atomic_inc(&mg->cache->stats.copies_avoided); | |
1114 | migration_success_pre_commit(mg); | |
1115 | } | |
1116 | ||
7ae34e77 JT |
1117 | static void calc_discard_block_range(struct cache *cache, struct bio *bio, |
1118 | dm_dblock_t *b, dm_dblock_t *e) | |
1119 | { | |
1120 | sector_t sb = bio->bi_iter.bi_sector; | |
1121 | sector_t se = bio_end_sector(bio); | |
1122 | ||
1123 | *b = to_dblock(dm_sector_div_up(sb, cache->discard_block_size)); | |
1124 | ||
1125 | if (se - sb < cache->discard_block_size) | |
1126 | *e = *b; | |
1127 | else | |
1128 | *e = to_dblock(block_div(se, cache->discard_block_size)); | |
1129 | } | |
1130 | ||
1131 | static void issue_discard(struct dm_cache_migration *mg) | |
1132 | { | |
1133 | dm_dblock_t b, e; | |
1134 | struct bio *bio = mg->new_ocell->holder; | |
1135 | ||
1136 | calc_discard_block_range(mg->cache, bio, &b, &e); | |
1137 | while (b != e) { | |
1138 | set_discard(mg->cache, b); | |
1139 | b = to_dblock(from_dblock(b) + 1); | |
1140 | } | |
1141 | ||
1142 | bio_endio(bio, 0); | |
1143 | cell_defer(mg->cache, mg->new_ocell, false); | |
1144 | free_migration(mg); | |
1145 | } | |
1146 | ||
1147 | static void issue_copy_or_discard(struct dm_cache_migration *mg) | |
c6b4fcba JT |
1148 | { |
1149 | bool avoid; | |
1150 | struct cache *cache = mg->cache; | |
1151 | ||
7ae34e77 JT |
1152 | if (mg->discard) { |
1153 | issue_discard(mg); | |
1154 | return; | |
1155 | } | |
1156 | ||
c6b4fcba JT |
1157 | if (mg->writeback || mg->demote) |
1158 | avoid = !is_dirty(cache, mg->cblock) || | |
1159 | is_discarded_oblock(cache, mg->old_oblock); | |
c9d28d5d JT |
1160 | else { |
1161 | struct bio *bio = mg->new_ocell->holder; | |
1162 | ||
c6b4fcba JT |
1163 | avoid = is_discarded_oblock(cache, mg->new_oblock); |
1164 | ||
f29a3147 JT |
1165 | if (writeback_mode(&cache->features) && |
1166 | !avoid && bio_writes_complete_block(cache, bio)) { | |
c9d28d5d JT |
1167 | issue_overwrite(mg, bio); |
1168 | return; | |
1169 | } | |
1170 | } | |
1171 | ||
7ae34e77 | 1172 | avoid ? avoid_copy(mg) : issue_copy(mg); |
c6b4fcba JT |
1173 | } |
1174 | ||
1175 | static void complete_migration(struct dm_cache_migration *mg) | |
1176 | { | |
1177 | if (mg->err) | |
1178 | migration_failure(mg); | |
1179 | else | |
1180 | migration_success_pre_commit(mg); | |
1181 | } | |
1182 | ||
1183 | static void process_migrations(struct cache *cache, struct list_head *head, | |
1184 | void (*fn)(struct dm_cache_migration *)) | |
1185 | { | |
1186 | unsigned long flags; | |
1187 | struct list_head list; | |
1188 | struct dm_cache_migration *mg, *tmp; | |
1189 | ||
1190 | INIT_LIST_HEAD(&list); | |
1191 | spin_lock_irqsave(&cache->lock, flags); | |
1192 | list_splice_init(head, &list); | |
1193 | spin_unlock_irqrestore(&cache->lock, flags); | |
1194 | ||
1195 | list_for_each_entry_safe(mg, tmp, &list, list) | |
1196 | fn(mg); | |
1197 | } | |
1198 | ||
1199 | static void __queue_quiesced_migration(struct dm_cache_migration *mg) | |
1200 | { | |
1201 | list_add_tail(&mg->list, &mg->cache->quiesced_migrations); | |
1202 | } | |
1203 | ||
1204 | static void queue_quiesced_migration(struct dm_cache_migration *mg) | |
1205 | { | |
1206 | unsigned long flags; | |
1207 | struct cache *cache = mg->cache; | |
1208 | ||
1209 | spin_lock_irqsave(&cache->lock, flags); | |
1210 | __queue_quiesced_migration(mg); | |
1211 | spin_unlock_irqrestore(&cache->lock, flags); | |
1212 | ||
1213 | wake_worker(cache); | |
1214 | } | |
1215 | ||
1216 | static void queue_quiesced_migrations(struct cache *cache, struct list_head *work) | |
1217 | { | |
1218 | unsigned long flags; | |
1219 | struct dm_cache_migration *mg, *tmp; | |
1220 | ||
1221 | spin_lock_irqsave(&cache->lock, flags); | |
1222 | list_for_each_entry_safe(mg, tmp, work, list) | |
1223 | __queue_quiesced_migration(mg); | |
1224 | spin_unlock_irqrestore(&cache->lock, flags); | |
1225 | ||
1226 | wake_worker(cache); | |
1227 | } | |
1228 | ||
1229 | static void check_for_quiesced_migrations(struct cache *cache, | |
1230 | struct per_bio_data *pb) | |
1231 | { | |
1232 | struct list_head work; | |
1233 | ||
1234 | if (!pb->all_io_entry) | |
1235 | return; | |
1236 | ||
1237 | INIT_LIST_HEAD(&work); | |
8c081b52 | 1238 | dm_deferred_entry_dec(pb->all_io_entry, &work); |
c6b4fcba JT |
1239 | |
1240 | if (!list_empty(&work)) | |
1241 | queue_quiesced_migrations(cache, &work); | |
1242 | } | |
1243 | ||
1244 | static void quiesce_migration(struct dm_cache_migration *mg) | |
1245 | { | |
1246 | if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list)) | |
1247 | queue_quiesced_migration(mg); | |
1248 | } | |
1249 | ||
1250 | static void promote(struct cache *cache, struct prealloc *structs, | |
1251 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1252 | struct dm_bio_prison_cell *cell) | |
1253 | { | |
1254 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1255 | ||
1256 | mg->err = false; | |
7ae34e77 | 1257 | mg->discard = false; |
c6b4fcba JT |
1258 | mg->writeback = false; |
1259 | mg->demote = false; | |
1260 | mg->promote = true; | |
c9d28d5d | 1261 | mg->requeue_holder = true; |
65790ff9 | 1262 | mg->invalidate = false; |
c6b4fcba JT |
1263 | mg->cache = cache; |
1264 | mg->new_oblock = oblock; | |
1265 | mg->cblock = cblock; | |
1266 | mg->old_ocell = NULL; | |
1267 | mg->new_ocell = cell; | |
1268 | mg->start_jiffies = jiffies; | |
1269 | ||
a59db676 | 1270 | inc_io_migrations(cache); |
c6b4fcba JT |
1271 | quiesce_migration(mg); |
1272 | } | |
1273 | ||
1274 | static void writeback(struct cache *cache, struct prealloc *structs, | |
1275 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1276 | struct dm_bio_prison_cell *cell) | |
1277 | { | |
1278 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1279 | ||
1280 | mg->err = false; | |
7ae34e77 | 1281 | mg->discard = false; |
c6b4fcba JT |
1282 | mg->writeback = true; |
1283 | mg->demote = false; | |
1284 | mg->promote = false; | |
c9d28d5d | 1285 | mg->requeue_holder = true; |
65790ff9 | 1286 | mg->invalidate = false; |
c6b4fcba JT |
1287 | mg->cache = cache; |
1288 | mg->old_oblock = oblock; | |
1289 | mg->cblock = cblock; | |
1290 | mg->old_ocell = cell; | |
1291 | mg->new_ocell = NULL; | |
1292 | mg->start_jiffies = jiffies; | |
1293 | ||
a59db676 | 1294 | inc_io_migrations(cache); |
c6b4fcba JT |
1295 | quiesce_migration(mg); |
1296 | } | |
1297 | ||
1298 | static void demote_then_promote(struct cache *cache, struct prealloc *structs, | |
1299 | dm_oblock_t old_oblock, dm_oblock_t new_oblock, | |
1300 | dm_cblock_t cblock, | |
1301 | struct dm_bio_prison_cell *old_ocell, | |
1302 | struct dm_bio_prison_cell *new_ocell) | |
1303 | { | |
1304 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1305 | ||
1306 | mg->err = false; | |
7ae34e77 | 1307 | mg->discard = false; |
c6b4fcba JT |
1308 | mg->writeback = false; |
1309 | mg->demote = true; | |
1310 | mg->promote = true; | |
c9d28d5d | 1311 | mg->requeue_holder = true; |
65790ff9 | 1312 | mg->invalidate = false; |
c6b4fcba JT |
1313 | mg->cache = cache; |
1314 | mg->old_oblock = old_oblock; | |
1315 | mg->new_oblock = new_oblock; | |
1316 | mg->cblock = cblock; | |
1317 | mg->old_ocell = old_ocell; | |
1318 | mg->new_ocell = new_ocell; | |
1319 | mg->start_jiffies = jiffies; | |
1320 | ||
a59db676 | 1321 | inc_io_migrations(cache); |
c6b4fcba JT |
1322 | quiesce_migration(mg); |
1323 | } | |
1324 | ||
2ee57d58 JT |
1325 | /* |
1326 | * Invalidate a cache entry. No writeback occurs; any changes in the cache | |
1327 | * block are thrown away. | |
1328 | */ | |
1329 | static void invalidate(struct cache *cache, struct prealloc *structs, | |
1330 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1331 | struct dm_bio_prison_cell *cell) | |
1332 | { | |
1333 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1334 | ||
1335 | mg->err = false; | |
7ae34e77 | 1336 | mg->discard = false; |
2ee57d58 JT |
1337 | mg->writeback = false; |
1338 | mg->demote = true; | |
1339 | mg->promote = false; | |
1340 | mg->requeue_holder = true; | |
65790ff9 | 1341 | mg->invalidate = true; |
2ee57d58 JT |
1342 | mg->cache = cache; |
1343 | mg->old_oblock = oblock; | |
1344 | mg->cblock = cblock; | |
1345 | mg->old_ocell = cell; | |
1346 | mg->new_ocell = NULL; | |
1347 | mg->start_jiffies = jiffies; | |
1348 | ||
a59db676 | 1349 | inc_io_migrations(cache); |
2ee57d58 JT |
1350 | quiesce_migration(mg); |
1351 | } | |
1352 | ||
7ae34e77 JT |
1353 | static void discard(struct cache *cache, struct prealloc *structs, |
1354 | struct dm_bio_prison_cell *cell) | |
1355 | { | |
1356 | struct dm_cache_migration *mg = prealloc_get_migration(structs); | |
1357 | ||
1358 | mg->err = false; | |
1359 | mg->discard = true; | |
1360 | mg->writeback = false; | |
1361 | mg->demote = false; | |
1362 | mg->promote = false; | |
1363 | mg->requeue_holder = false; | |
1364 | mg->invalidate = false; | |
1365 | mg->cache = cache; | |
1366 | mg->old_ocell = NULL; | |
1367 | mg->new_ocell = cell; | |
1368 | mg->start_jiffies = jiffies; | |
1369 | ||
1370 | quiesce_migration(mg); | |
1371 | } | |
1372 | ||
c6b4fcba JT |
1373 | /*---------------------------------------------------------------- |
1374 | * bio processing | |
1375 | *--------------------------------------------------------------*/ | |
1376 | static void defer_bio(struct cache *cache, struct bio *bio) | |
1377 | { | |
1378 | unsigned long flags; | |
1379 | ||
1380 | spin_lock_irqsave(&cache->lock, flags); | |
1381 | bio_list_add(&cache->deferred_bios, bio); | |
1382 | spin_unlock_irqrestore(&cache->lock, flags); | |
1383 | ||
1384 | wake_worker(cache); | |
1385 | } | |
1386 | ||
1387 | static void process_flush_bio(struct cache *cache, struct bio *bio) | |
1388 | { | |
19b0092e MS |
1389 | size_t pb_data_size = get_per_bio_data_size(cache); |
1390 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba | 1391 | |
4f024f37 | 1392 | BUG_ON(bio->bi_iter.bi_size); |
c6b4fcba JT |
1393 | if (!pb->req_nr) |
1394 | remap_to_origin(cache, bio); | |
1395 | else | |
1396 | remap_to_cache(cache, bio, 0); | |
1397 | ||
8c081b52 JT |
1398 | /* |
1399 | * REQ_FLUSH is not directed at any particular block so we don't | |
1400 | * need to inc_ds(). REQ_FUA's are split into a write + REQ_FLUSH | |
1401 | * by dm-core. | |
1402 | */ | |
c6b4fcba JT |
1403 | issue(cache, bio); |
1404 | } | |
1405 | ||
7ae34e77 JT |
1406 | static void process_discard_bio(struct cache *cache, struct prealloc *structs, |
1407 | struct bio *bio) | |
c6b4fcba | 1408 | { |
7ae34e77 JT |
1409 | int r; |
1410 | dm_dblock_t b, e; | |
1411 | struct dm_bio_prison_cell *cell_prealloc, *new_ocell; | |
c6b4fcba | 1412 | |
7ae34e77 JT |
1413 | calc_discard_block_range(cache, bio, &b, &e); |
1414 | if (b == e) { | |
1415 | bio_endio(bio, 0); | |
1416 | return; | |
1417 | } | |
c6b4fcba | 1418 | |
7ae34e77 JT |
1419 | cell_prealloc = prealloc_get_cell(structs); |
1420 | r = bio_detain_range(cache, dblock_to_oblock(cache, b), dblock_to_oblock(cache, e), bio, cell_prealloc, | |
1421 | (cell_free_fn) prealloc_put_cell, | |
1422 | structs, &new_ocell); | |
1423 | if (r > 0) | |
1424 | return; | |
c6b4fcba | 1425 | |
7ae34e77 | 1426 | discard(cache, structs, new_ocell); |
c6b4fcba JT |
1427 | } |
1428 | ||
1429 | static bool spare_migration_bandwidth(struct cache *cache) | |
1430 | { | |
a59db676 | 1431 | sector_t current_volume = (atomic_read(&cache->nr_io_migrations) + 1) * |
c6b4fcba JT |
1432 | cache->sectors_per_block; |
1433 | return current_volume < cache->migration_threshold; | |
1434 | } | |
1435 | ||
c6b4fcba JT |
1436 | static void inc_hit_counter(struct cache *cache, struct bio *bio) |
1437 | { | |
1438 | atomic_inc(bio_data_dir(bio) == READ ? | |
1439 | &cache->stats.read_hit : &cache->stats.write_hit); | |
1440 | } | |
1441 | ||
1442 | static void inc_miss_counter(struct cache *cache, struct bio *bio) | |
1443 | { | |
1444 | atomic_inc(bio_data_dir(bio) == READ ? | |
1445 | &cache->stats.read_miss : &cache->stats.write_miss); | |
1446 | } | |
1447 | ||
1448 | static void process_bio(struct cache *cache, struct prealloc *structs, | |
1449 | struct bio *bio) | |
1450 | { | |
1451 | int r; | |
1452 | bool release_cell = true; | |
1453 | dm_oblock_t block = get_bio_block(cache, bio); | |
1454 | struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell; | |
1455 | struct policy_result lookup_result; | |
2ee57d58 | 1456 | bool passthrough = passthrough_mode(&cache->features); |
43c32bf2 | 1457 | bool discarded_block, can_migrate; |
c6b4fcba JT |
1458 | |
1459 | /* | |
1460 | * Check to see if that block is currently migrating. | |
1461 | */ | |
1462 | cell_prealloc = prealloc_get_cell(structs); | |
1463 | r = bio_detain(cache, block, bio, cell_prealloc, | |
1464 | (cell_free_fn) prealloc_put_cell, | |
1465 | structs, &new_ocell); | |
1466 | if (r > 0) | |
1467 | return; | |
1468 | ||
43c32bf2 JT |
1469 | discarded_block = is_discarded_oblock(cache, block); |
1470 | can_migrate = !passthrough && (discarded_block || spare_migration_bandwidth(cache)); | |
1471 | ||
c6b4fcba JT |
1472 | r = policy_map(cache->policy, block, true, can_migrate, discarded_block, |
1473 | bio, &lookup_result); | |
1474 | ||
1475 | if (r == -EWOULDBLOCK) | |
1476 | /* migration has been denied */ | |
1477 | lookup_result.op = POLICY_MISS; | |
1478 | ||
1479 | switch (lookup_result.op) { | |
1480 | case POLICY_HIT: | |
2ee57d58 JT |
1481 | if (passthrough) { |
1482 | inc_miss_counter(cache, bio); | |
c6b4fcba | 1483 | |
2ee57d58 JT |
1484 | /* |
1485 | * Passthrough always maps to the origin, | |
1486 | * invalidating any cache blocks that are written | |
1487 | * to. | |
1488 | */ | |
1489 | ||
1490 | if (bio_data_dir(bio) == WRITE) { | |
1491 | atomic_inc(&cache->stats.demotion); | |
1492 | invalidate(cache, structs, block, lookup_result.cblock, new_ocell); | |
1493 | release_cell = false; | |
1494 | ||
1495 | } else { | |
1496 | /* FIXME: factor out issue_origin() */ | |
2ee57d58 | 1497 | remap_to_origin_clear_discard(cache, bio, block); |
8c081b52 | 1498 | inc_and_issue(cache, bio, new_ocell); |
2ee57d58 JT |
1499 | } |
1500 | } else { | |
1501 | inc_hit_counter(cache, bio); | |
1502 | ||
1503 | if (bio_data_dir(bio) == WRITE && | |
1504 | writethrough_mode(&cache->features) && | |
1505 | !is_dirty(cache, lookup_result.cblock)) { | |
2ee57d58 | 1506 | remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); |
8c081b52 JT |
1507 | inc_and_issue(cache, bio, new_ocell); |
1508 | ||
1509 | } else { | |
1510 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); | |
1511 | inc_and_issue(cache, bio, new_ocell); | |
1512 | } | |
2ee57d58 | 1513 | } |
c6b4fcba | 1514 | |
c6b4fcba JT |
1515 | break; |
1516 | ||
1517 | case POLICY_MISS: | |
1518 | inc_miss_counter(cache, bio); | |
e2e74d61 | 1519 | remap_to_origin_clear_discard(cache, bio, block); |
8c081b52 | 1520 | inc_and_issue(cache, bio, new_ocell); |
c6b4fcba JT |
1521 | break; |
1522 | ||
1523 | case POLICY_NEW: | |
1524 | atomic_inc(&cache->stats.promotion); | |
1525 | promote(cache, structs, block, lookup_result.cblock, new_ocell); | |
1526 | release_cell = false; | |
1527 | break; | |
1528 | ||
1529 | case POLICY_REPLACE: | |
1530 | cell_prealloc = prealloc_get_cell(structs); | |
1531 | r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc, | |
1532 | (cell_free_fn) prealloc_put_cell, | |
1533 | structs, &old_ocell); | |
1534 | if (r > 0) { | |
1535 | /* | |
1536 | * We have to be careful to avoid lock inversion of | |
1537 | * the cells. So we back off, and wait for the | |
1538 | * old_ocell to become free. | |
1539 | */ | |
1540 | policy_force_mapping(cache->policy, block, | |
1541 | lookup_result.old_oblock); | |
1542 | atomic_inc(&cache->stats.cache_cell_clash); | |
1543 | break; | |
1544 | } | |
1545 | atomic_inc(&cache->stats.demotion); | |
1546 | atomic_inc(&cache->stats.promotion); | |
1547 | ||
1548 | demote_then_promote(cache, structs, lookup_result.old_oblock, | |
1549 | block, lookup_result.cblock, | |
1550 | old_ocell, new_ocell); | |
1551 | release_cell = false; | |
1552 | break; | |
1553 | ||
1554 | default: | |
1555 | DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__, | |
1556 | (unsigned) lookup_result.op); | |
1557 | bio_io_error(bio); | |
1558 | } | |
1559 | ||
1560 | if (release_cell) | |
1561 | cell_defer(cache, new_ocell, false); | |
1562 | } | |
1563 | ||
1564 | static int need_commit_due_to_time(struct cache *cache) | |
1565 | { | |
0f30af98 MS |
1566 | return !time_in_range(jiffies, cache->last_commit_jiffies, |
1567 | cache->last_commit_jiffies + COMMIT_PERIOD); | |
c6b4fcba JT |
1568 | } |
1569 | ||
1570 | static int commit_if_needed(struct cache *cache) | |
1571 | { | |
ffcbcb67 HM |
1572 | int r = 0; |
1573 | ||
1574 | if ((cache->commit_requested || need_commit_due_to_time(cache)) && | |
1575 | dm_cache_changed_this_transaction(cache->cmd)) { | |
c6b4fcba | 1576 | atomic_inc(&cache->stats.commit_count); |
c6b4fcba | 1577 | cache->commit_requested = false; |
ffcbcb67 HM |
1578 | r = dm_cache_commit(cache->cmd, false); |
1579 | cache->last_commit_jiffies = jiffies; | |
c6b4fcba JT |
1580 | } |
1581 | ||
ffcbcb67 | 1582 | return r; |
c6b4fcba JT |
1583 | } |
1584 | ||
1585 | static void process_deferred_bios(struct cache *cache) | |
1586 | { | |
1587 | unsigned long flags; | |
1588 | struct bio_list bios; | |
1589 | struct bio *bio; | |
1590 | struct prealloc structs; | |
1591 | ||
1592 | memset(&structs, 0, sizeof(structs)); | |
1593 | bio_list_init(&bios); | |
1594 | ||
1595 | spin_lock_irqsave(&cache->lock, flags); | |
1596 | bio_list_merge(&bios, &cache->deferred_bios); | |
1597 | bio_list_init(&cache->deferred_bios); | |
1598 | spin_unlock_irqrestore(&cache->lock, flags); | |
1599 | ||
1600 | while (!bio_list_empty(&bios)) { | |
1601 | /* | |
1602 | * If we've got no free migration structs, and processing | |
1603 | * this bio might require one, we pause until there are some | |
1604 | * prepared mappings to process. | |
1605 | */ | |
1606 | if (prealloc_data_structs(cache, &structs)) { | |
1607 | spin_lock_irqsave(&cache->lock, flags); | |
1608 | bio_list_merge(&cache->deferred_bios, &bios); | |
1609 | spin_unlock_irqrestore(&cache->lock, flags); | |
1610 | break; | |
1611 | } | |
1612 | ||
1613 | bio = bio_list_pop(&bios); | |
1614 | ||
1615 | if (bio->bi_rw & REQ_FLUSH) | |
1616 | process_flush_bio(cache, bio); | |
1617 | else if (bio->bi_rw & REQ_DISCARD) | |
7ae34e77 | 1618 | process_discard_bio(cache, &structs, bio); |
c6b4fcba JT |
1619 | else |
1620 | process_bio(cache, &structs, bio); | |
1621 | } | |
1622 | ||
1623 | prealloc_free_structs(cache, &structs); | |
1624 | } | |
1625 | ||
1626 | static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) | |
1627 | { | |
1628 | unsigned long flags; | |
1629 | struct bio_list bios; | |
1630 | struct bio *bio; | |
1631 | ||
1632 | bio_list_init(&bios); | |
1633 | ||
1634 | spin_lock_irqsave(&cache->lock, flags); | |
1635 | bio_list_merge(&bios, &cache->deferred_flush_bios); | |
1636 | bio_list_init(&cache->deferred_flush_bios); | |
1637 | spin_unlock_irqrestore(&cache->lock, flags); | |
1638 | ||
8c081b52 JT |
1639 | /* |
1640 | * These bios have already been through inc_ds() | |
1641 | */ | |
c6b4fcba JT |
1642 | while ((bio = bio_list_pop(&bios))) |
1643 | submit_bios ? generic_make_request(bio) : bio_io_error(bio); | |
1644 | } | |
1645 | ||
e2e74d61 JT |
1646 | static void process_deferred_writethrough_bios(struct cache *cache) |
1647 | { | |
1648 | unsigned long flags; | |
1649 | struct bio_list bios; | |
1650 | struct bio *bio; | |
1651 | ||
1652 | bio_list_init(&bios); | |
1653 | ||
1654 | spin_lock_irqsave(&cache->lock, flags); | |
1655 | bio_list_merge(&bios, &cache->deferred_writethrough_bios); | |
1656 | bio_list_init(&cache->deferred_writethrough_bios); | |
1657 | spin_unlock_irqrestore(&cache->lock, flags); | |
1658 | ||
8c081b52 JT |
1659 | /* |
1660 | * These bios have already been through inc_ds() | |
1661 | */ | |
e2e74d61 JT |
1662 | while ((bio = bio_list_pop(&bios))) |
1663 | generic_make_request(bio); | |
1664 | } | |
1665 | ||
c6b4fcba JT |
1666 | static void writeback_some_dirty_blocks(struct cache *cache) |
1667 | { | |
1668 | int r = 0; | |
1669 | dm_oblock_t oblock; | |
1670 | dm_cblock_t cblock; | |
1671 | struct prealloc structs; | |
1672 | struct dm_bio_prison_cell *old_ocell; | |
1673 | ||
1674 | memset(&structs, 0, sizeof(structs)); | |
1675 | ||
1676 | while (spare_migration_bandwidth(cache)) { | |
1677 | if (prealloc_data_structs(cache, &structs)) | |
1678 | break; | |
1679 | ||
1680 | r = policy_writeback_work(cache->policy, &oblock, &cblock); | |
1681 | if (r) | |
1682 | break; | |
1683 | ||
1684 | r = get_cell(cache, oblock, &structs, &old_ocell); | |
1685 | if (r) { | |
1686 | policy_set_dirty(cache->policy, oblock); | |
1687 | break; | |
1688 | } | |
1689 | ||
1690 | writeback(cache, &structs, oblock, cblock, old_ocell); | |
1691 | } | |
1692 | ||
1693 | prealloc_free_structs(cache, &structs); | |
1694 | } | |
1695 | ||
65790ff9 JT |
1696 | /*---------------------------------------------------------------- |
1697 | * Invalidations. | |
1698 | * Dropping something from the cache *without* writing back. | |
1699 | *--------------------------------------------------------------*/ | |
1700 | ||
1701 | static void process_invalidation_request(struct cache *cache, struct invalidation_request *req) | |
1702 | { | |
1703 | int r = 0; | |
1704 | uint64_t begin = from_cblock(req->cblocks->begin); | |
1705 | uint64_t end = from_cblock(req->cblocks->end); | |
1706 | ||
1707 | while (begin != end) { | |
1708 | r = policy_remove_cblock(cache->policy, to_cblock(begin)); | |
1709 | if (!r) { | |
1710 | r = dm_cache_remove_mapping(cache->cmd, to_cblock(begin)); | |
1711 | if (r) | |
1712 | break; | |
1713 | ||
1714 | } else if (r == -ENODATA) { | |
1715 | /* harmless, already unmapped */ | |
1716 | r = 0; | |
1717 | ||
1718 | } else { | |
1719 | DMERR("policy_remove_cblock failed"); | |
1720 | break; | |
1721 | } | |
1722 | ||
1723 | begin++; | |
1724 | } | |
1725 | ||
1726 | cache->commit_requested = true; | |
1727 | ||
1728 | req->err = r; | |
1729 | atomic_set(&req->complete, 1); | |
1730 | ||
1731 | wake_up(&req->result_wait); | |
1732 | } | |
1733 | ||
1734 | static void process_invalidation_requests(struct cache *cache) | |
1735 | { | |
1736 | struct list_head list; | |
1737 | struct invalidation_request *req, *tmp; | |
1738 | ||
1739 | INIT_LIST_HEAD(&list); | |
1740 | spin_lock(&cache->invalidation_lock); | |
1741 | list_splice_init(&cache->invalidation_requests, &list); | |
1742 | spin_unlock(&cache->invalidation_lock); | |
1743 | ||
1744 | list_for_each_entry_safe (req, tmp, &list, list) | |
1745 | process_invalidation_request(cache, req); | |
1746 | } | |
1747 | ||
c6b4fcba JT |
1748 | /*---------------------------------------------------------------- |
1749 | * Main worker loop | |
1750 | *--------------------------------------------------------------*/ | |
66cb1910 | 1751 | static bool is_quiescing(struct cache *cache) |
c6b4fcba | 1752 | { |
238f8363 | 1753 | return atomic_read(&cache->quiescing); |
c6b4fcba JT |
1754 | } |
1755 | ||
66cb1910 JT |
1756 | static void ack_quiescing(struct cache *cache) |
1757 | { | |
1758 | if (is_quiescing(cache)) { | |
1759 | atomic_inc(&cache->quiescing_ack); | |
1760 | wake_up(&cache->quiescing_wait); | |
1761 | } | |
1762 | } | |
1763 | ||
1764 | static void wait_for_quiescing_ack(struct cache *cache) | |
1765 | { | |
1766 | wait_event(cache->quiescing_wait, atomic_read(&cache->quiescing_ack)); | |
1767 | } | |
1768 | ||
1769 | static void start_quiescing(struct cache *cache) | |
c6b4fcba | 1770 | { |
238f8363 | 1771 | atomic_inc(&cache->quiescing); |
66cb1910 | 1772 | wait_for_quiescing_ack(cache); |
c6b4fcba JT |
1773 | } |
1774 | ||
66cb1910 | 1775 | static void stop_quiescing(struct cache *cache) |
c6b4fcba | 1776 | { |
238f8363 | 1777 | atomic_set(&cache->quiescing, 0); |
66cb1910 | 1778 | atomic_set(&cache->quiescing_ack, 0); |
c6b4fcba JT |
1779 | } |
1780 | ||
1781 | static void wait_for_migrations(struct cache *cache) | |
1782 | { | |
a59db676 | 1783 | wait_event(cache->migration_wait, !atomic_read(&cache->nr_allocated_migrations)); |
c6b4fcba JT |
1784 | } |
1785 | ||
1786 | static void stop_worker(struct cache *cache) | |
1787 | { | |
1788 | cancel_delayed_work(&cache->waker); | |
1789 | flush_workqueue(cache->wq); | |
1790 | } | |
1791 | ||
1792 | static void requeue_deferred_io(struct cache *cache) | |
1793 | { | |
1794 | struct bio *bio; | |
1795 | struct bio_list bios; | |
1796 | ||
1797 | bio_list_init(&bios); | |
1798 | bio_list_merge(&bios, &cache->deferred_bios); | |
1799 | bio_list_init(&cache->deferred_bios); | |
1800 | ||
1801 | while ((bio = bio_list_pop(&bios))) | |
1802 | bio_endio(bio, DM_ENDIO_REQUEUE); | |
1803 | } | |
1804 | ||
1805 | static int more_work(struct cache *cache) | |
1806 | { | |
1807 | if (is_quiescing(cache)) | |
1808 | return !list_empty(&cache->quiesced_migrations) || | |
1809 | !list_empty(&cache->completed_migrations) || | |
1810 | !list_empty(&cache->need_commit_migrations); | |
1811 | else | |
1812 | return !bio_list_empty(&cache->deferred_bios) || | |
1813 | !bio_list_empty(&cache->deferred_flush_bios) || | |
e2e74d61 | 1814 | !bio_list_empty(&cache->deferred_writethrough_bios) || |
c6b4fcba JT |
1815 | !list_empty(&cache->quiesced_migrations) || |
1816 | !list_empty(&cache->completed_migrations) || | |
65790ff9 JT |
1817 | !list_empty(&cache->need_commit_migrations) || |
1818 | cache->invalidate; | |
c6b4fcba JT |
1819 | } |
1820 | ||
1821 | static void do_worker(struct work_struct *ws) | |
1822 | { | |
1823 | struct cache *cache = container_of(ws, struct cache, worker); | |
1824 | ||
1825 | do { | |
66cb1910 JT |
1826 | if (!is_quiescing(cache)) { |
1827 | writeback_some_dirty_blocks(cache); | |
1828 | process_deferred_writethrough_bios(cache); | |
c6b4fcba | 1829 | process_deferred_bios(cache); |
65790ff9 | 1830 | process_invalidation_requests(cache); |
66cb1910 | 1831 | } |
c6b4fcba | 1832 | |
7ae34e77 | 1833 | process_migrations(cache, &cache->quiesced_migrations, issue_copy_or_discard); |
c6b4fcba JT |
1834 | process_migrations(cache, &cache->completed_migrations, complete_migration); |
1835 | ||
c6b4fcba JT |
1836 | if (commit_if_needed(cache)) { |
1837 | process_deferred_flush_bios(cache, false); | |
304affaa | 1838 | process_migrations(cache, &cache->need_commit_migrations, migration_failure); |
c6b4fcba JT |
1839 | |
1840 | /* | |
1841 | * FIXME: rollback metadata or just go into a | |
1842 | * failure mode and error everything | |
1843 | */ | |
1844 | } else { | |
1845 | process_deferred_flush_bios(cache, true); | |
1846 | process_migrations(cache, &cache->need_commit_migrations, | |
1847 | migration_success_post_commit); | |
1848 | } | |
66cb1910 JT |
1849 | |
1850 | ack_quiescing(cache); | |
1851 | ||
c6b4fcba JT |
1852 | } while (more_work(cache)); |
1853 | } | |
1854 | ||
1855 | /* | |
1856 | * We want to commit periodically so that not too much | |
1857 | * unwritten metadata builds up. | |
1858 | */ | |
1859 | static void do_waker(struct work_struct *ws) | |
1860 | { | |
1861 | struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker); | |
f8350daf | 1862 | policy_tick(cache->policy); |
c6b4fcba JT |
1863 | wake_worker(cache); |
1864 | queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); | |
1865 | } | |
1866 | ||
1867 | /*----------------------------------------------------------------*/ | |
1868 | ||
1869 | static int is_congested(struct dm_dev *dev, int bdi_bits) | |
1870 | { | |
1871 | struct request_queue *q = bdev_get_queue(dev->bdev); | |
1872 | return bdi_congested(&q->backing_dev_info, bdi_bits); | |
1873 | } | |
1874 | ||
1875 | static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits) | |
1876 | { | |
1877 | struct cache *cache = container_of(cb, struct cache, callbacks); | |
1878 | ||
1879 | return is_congested(cache->origin_dev, bdi_bits) || | |
1880 | is_congested(cache->cache_dev, bdi_bits); | |
1881 | } | |
1882 | ||
1883 | /*---------------------------------------------------------------- | |
1884 | * Target methods | |
1885 | *--------------------------------------------------------------*/ | |
1886 | ||
1887 | /* | |
1888 | * This function gets called on the error paths of the constructor, so we | |
1889 | * have to cope with a partially initialised struct. | |
1890 | */ | |
1891 | static void destroy(struct cache *cache) | |
1892 | { | |
1893 | unsigned i; | |
1894 | ||
c6b4fcba JT |
1895 | if (cache->migration_pool) |
1896 | mempool_destroy(cache->migration_pool); | |
1897 | ||
1898 | if (cache->all_io_ds) | |
1899 | dm_deferred_set_destroy(cache->all_io_ds); | |
1900 | ||
1901 | if (cache->prison) | |
1902 | dm_bio_prison_destroy(cache->prison); | |
1903 | ||
1904 | if (cache->wq) | |
1905 | destroy_workqueue(cache->wq); | |
1906 | ||
1907 | if (cache->dirty_bitset) | |
1908 | free_bitset(cache->dirty_bitset); | |
1909 | ||
1910 | if (cache->discard_bitset) | |
1911 | free_bitset(cache->discard_bitset); | |
1912 | ||
1913 | if (cache->copier) | |
1914 | dm_kcopyd_client_destroy(cache->copier); | |
1915 | ||
1916 | if (cache->cmd) | |
1917 | dm_cache_metadata_close(cache->cmd); | |
1918 | ||
1919 | if (cache->metadata_dev) | |
1920 | dm_put_device(cache->ti, cache->metadata_dev); | |
1921 | ||
1922 | if (cache->origin_dev) | |
1923 | dm_put_device(cache->ti, cache->origin_dev); | |
1924 | ||
1925 | if (cache->cache_dev) | |
1926 | dm_put_device(cache->ti, cache->cache_dev); | |
1927 | ||
1928 | if (cache->policy) | |
1929 | dm_cache_policy_destroy(cache->policy); | |
1930 | ||
1931 | for (i = 0; i < cache->nr_ctr_args ; i++) | |
1932 | kfree(cache->ctr_args[i]); | |
1933 | kfree(cache->ctr_args); | |
1934 | ||
1935 | kfree(cache); | |
1936 | } | |
1937 | ||
1938 | static void cache_dtr(struct dm_target *ti) | |
1939 | { | |
1940 | struct cache *cache = ti->private; | |
1941 | ||
1942 | destroy(cache); | |
1943 | } | |
1944 | ||
1945 | static sector_t get_dev_size(struct dm_dev *dev) | |
1946 | { | |
1947 | return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT; | |
1948 | } | |
1949 | ||
1950 | /*----------------------------------------------------------------*/ | |
1951 | ||
1952 | /* | |
1953 | * Construct a cache device mapping. | |
1954 | * | |
1955 | * cache <metadata dev> <cache dev> <origin dev> <block size> | |
1956 | * <#feature args> [<feature arg>]* | |
1957 | * <policy> <#policy args> [<policy arg>]* | |
1958 | * | |
1959 | * metadata dev : fast device holding the persistent metadata | |
1960 | * cache dev : fast device holding cached data blocks | |
1961 | * origin dev : slow device holding original data blocks | |
1962 | * block size : cache unit size in sectors | |
1963 | * | |
1964 | * #feature args : number of feature arguments passed | |
1965 | * feature args : writethrough. (The default is writeback.) | |
1966 | * | |
1967 | * policy : the replacement policy to use | |
1968 | * #policy args : an even number of policy arguments corresponding | |
1969 | * to key/value pairs passed to the policy | |
1970 | * policy args : key/value pairs passed to the policy | |
1971 | * E.g. 'sequential_threshold 1024' | |
1972 | * See cache-policies.txt for details. | |
1973 | * | |
1974 | * Optional feature arguments are: | |
1975 | * writethrough : write through caching that prohibits cache block | |
1976 | * content from being different from origin block content. | |
1977 | * Without this argument, the default behaviour is to write | |
1978 | * back cache block contents later for performance reasons, | |
1979 | * so they may differ from the corresponding origin blocks. | |
1980 | */ | |
1981 | struct cache_args { | |
1982 | struct dm_target *ti; | |
1983 | ||
1984 | struct dm_dev *metadata_dev; | |
1985 | ||
1986 | struct dm_dev *cache_dev; | |
1987 | sector_t cache_sectors; | |
1988 | ||
1989 | struct dm_dev *origin_dev; | |
1990 | sector_t origin_sectors; | |
1991 | ||
1992 | uint32_t block_size; | |
1993 | ||
1994 | const char *policy_name; | |
1995 | int policy_argc; | |
1996 | const char **policy_argv; | |
1997 | ||
1998 | struct cache_features features; | |
1999 | }; | |
2000 | ||
2001 | static void destroy_cache_args(struct cache_args *ca) | |
2002 | { | |
2003 | if (ca->metadata_dev) | |
2004 | dm_put_device(ca->ti, ca->metadata_dev); | |
2005 | ||
2006 | if (ca->cache_dev) | |
2007 | dm_put_device(ca->ti, ca->cache_dev); | |
2008 | ||
2009 | if (ca->origin_dev) | |
2010 | dm_put_device(ca->ti, ca->origin_dev); | |
2011 | ||
2012 | kfree(ca); | |
2013 | } | |
2014 | ||
2015 | static bool at_least_one_arg(struct dm_arg_set *as, char **error) | |
2016 | { | |
2017 | if (!as->argc) { | |
2018 | *error = "Insufficient args"; | |
2019 | return false; | |
2020 | } | |
2021 | ||
2022 | return true; | |
2023 | } | |
2024 | ||
2025 | static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as, | |
2026 | char **error) | |
2027 | { | |
2028 | int r; | |
2029 | sector_t metadata_dev_size; | |
2030 | char b[BDEVNAME_SIZE]; | |
2031 | ||
2032 | if (!at_least_one_arg(as, error)) | |
2033 | return -EINVAL; | |
2034 | ||
2035 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
2036 | &ca->metadata_dev); | |
2037 | if (r) { | |
2038 | *error = "Error opening metadata device"; | |
2039 | return r; | |
2040 | } | |
2041 | ||
2042 | metadata_dev_size = get_dev_size(ca->metadata_dev); | |
2043 | if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING) | |
2044 | DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", | |
2045 | bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS); | |
2046 | ||
2047 | return 0; | |
2048 | } | |
2049 | ||
2050 | static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as, | |
2051 | char **error) | |
2052 | { | |
2053 | int r; | |
2054 | ||
2055 | if (!at_least_one_arg(as, error)) | |
2056 | return -EINVAL; | |
2057 | ||
2058 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
2059 | &ca->cache_dev); | |
2060 | if (r) { | |
2061 | *error = "Error opening cache device"; | |
2062 | return r; | |
2063 | } | |
2064 | ca->cache_sectors = get_dev_size(ca->cache_dev); | |
2065 | ||
2066 | return 0; | |
2067 | } | |
2068 | ||
2069 | static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, | |
2070 | char **error) | |
2071 | { | |
2072 | int r; | |
2073 | ||
2074 | if (!at_least_one_arg(as, error)) | |
2075 | return -EINVAL; | |
2076 | ||
2077 | r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, | |
2078 | &ca->origin_dev); | |
2079 | if (r) { | |
2080 | *error = "Error opening origin device"; | |
2081 | return r; | |
2082 | } | |
2083 | ||
2084 | ca->origin_sectors = get_dev_size(ca->origin_dev); | |
2085 | if (ca->ti->len > ca->origin_sectors) { | |
2086 | *error = "Device size larger than cached device"; | |
2087 | return -EINVAL; | |
2088 | } | |
2089 | ||
2090 | return 0; | |
2091 | } | |
2092 | ||
2093 | static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, | |
2094 | char **error) | |
2095 | { | |
05473044 | 2096 | unsigned long block_size; |
c6b4fcba JT |
2097 | |
2098 | if (!at_least_one_arg(as, error)) | |
2099 | return -EINVAL; | |
2100 | ||
05473044 MS |
2101 | if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size || |
2102 | block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || | |
2103 | block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || | |
2104 | block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { | |
c6b4fcba JT |
2105 | *error = "Invalid data block size"; |
2106 | return -EINVAL; | |
2107 | } | |
2108 | ||
05473044 | 2109 | if (block_size > ca->cache_sectors) { |
c6b4fcba JT |
2110 | *error = "Data block size is larger than the cache device"; |
2111 | return -EINVAL; | |
2112 | } | |
2113 | ||
05473044 | 2114 | ca->block_size = block_size; |
c6b4fcba JT |
2115 | |
2116 | return 0; | |
2117 | } | |
2118 | ||
2119 | static void init_features(struct cache_features *cf) | |
2120 | { | |
2121 | cf->mode = CM_WRITE; | |
2ee57d58 | 2122 | cf->io_mode = CM_IO_WRITEBACK; |
c6b4fcba JT |
2123 | } |
2124 | ||
2125 | static int parse_features(struct cache_args *ca, struct dm_arg_set *as, | |
2126 | char **error) | |
2127 | { | |
2128 | static struct dm_arg _args[] = { | |
2129 | {0, 1, "Invalid number of cache feature arguments"}, | |
2130 | }; | |
2131 | ||
2132 | int r; | |
2133 | unsigned argc; | |
2134 | const char *arg; | |
2135 | struct cache_features *cf = &ca->features; | |
2136 | ||
2137 | init_features(cf); | |
2138 | ||
2139 | r = dm_read_arg_group(_args, as, &argc, error); | |
2140 | if (r) | |
2141 | return -EINVAL; | |
2142 | ||
2143 | while (argc--) { | |
2144 | arg = dm_shift_arg(as); | |
2145 | ||
2146 | if (!strcasecmp(arg, "writeback")) | |
2ee57d58 | 2147 | cf->io_mode = CM_IO_WRITEBACK; |
c6b4fcba JT |
2148 | |
2149 | else if (!strcasecmp(arg, "writethrough")) | |
2ee57d58 JT |
2150 | cf->io_mode = CM_IO_WRITETHROUGH; |
2151 | ||
2152 | else if (!strcasecmp(arg, "passthrough")) | |
2153 | cf->io_mode = CM_IO_PASSTHROUGH; | |
c6b4fcba JT |
2154 | |
2155 | else { | |
2156 | *error = "Unrecognised cache feature requested"; | |
2157 | return -EINVAL; | |
2158 | } | |
2159 | } | |
2160 | ||
2161 | return 0; | |
2162 | } | |
2163 | ||
2164 | static int parse_policy(struct cache_args *ca, struct dm_arg_set *as, | |
2165 | char **error) | |
2166 | { | |
2167 | static struct dm_arg _args[] = { | |
2168 | {0, 1024, "Invalid number of policy arguments"}, | |
2169 | }; | |
2170 | ||
2171 | int r; | |
2172 | ||
2173 | if (!at_least_one_arg(as, error)) | |
2174 | return -EINVAL; | |
2175 | ||
2176 | ca->policy_name = dm_shift_arg(as); | |
2177 | ||
2178 | r = dm_read_arg_group(_args, as, &ca->policy_argc, error); | |
2179 | if (r) | |
2180 | return -EINVAL; | |
2181 | ||
2182 | ca->policy_argv = (const char **)as->argv; | |
2183 | dm_consume_args(as, ca->policy_argc); | |
2184 | ||
2185 | return 0; | |
2186 | } | |
2187 | ||
2188 | static int parse_cache_args(struct cache_args *ca, int argc, char **argv, | |
2189 | char **error) | |
2190 | { | |
2191 | int r; | |
2192 | struct dm_arg_set as; | |
2193 | ||
2194 | as.argc = argc; | |
2195 | as.argv = argv; | |
2196 | ||
2197 | r = parse_metadata_dev(ca, &as, error); | |
2198 | if (r) | |
2199 | return r; | |
2200 | ||
2201 | r = parse_cache_dev(ca, &as, error); | |
2202 | if (r) | |
2203 | return r; | |
2204 | ||
2205 | r = parse_origin_dev(ca, &as, error); | |
2206 | if (r) | |
2207 | return r; | |
2208 | ||
2209 | r = parse_block_size(ca, &as, error); | |
2210 | if (r) | |
2211 | return r; | |
2212 | ||
2213 | r = parse_features(ca, &as, error); | |
2214 | if (r) | |
2215 | return r; | |
2216 | ||
2217 | r = parse_policy(ca, &as, error); | |
2218 | if (r) | |
2219 | return r; | |
2220 | ||
2221 | return 0; | |
2222 | } | |
2223 | ||
2224 | /*----------------------------------------------------------------*/ | |
2225 | ||
2226 | static struct kmem_cache *migration_cache; | |
2227 | ||
2c73c471 AK |
2228 | #define NOT_CORE_OPTION 1 |
2229 | ||
2f14f4b5 | 2230 | static int process_config_option(struct cache *cache, const char *key, const char *value) |
2c73c471 AK |
2231 | { |
2232 | unsigned long tmp; | |
2233 | ||
2f14f4b5 JT |
2234 | if (!strcasecmp(key, "migration_threshold")) { |
2235 | if (kstrtoul(value, 10, &tmp)) | |
2c73c471 AK |
2236 | return -EINVAL; |
2237 | ||
2238 | cache->migration_threshold = tmp; | |
2239 | return 0; | |
2240 | } | |
2241 | ||
2242 | return NOT_CORE_OPTION; | |
2243 | } | |
2244 | ||
2f14f4b5 JT |
2245 | static int set_config_value(struct cache *cache, const char *key, const char *value) |
2246 | { | |
2247 | int r = process_config_option(cache, key, value); | |
2248 | ||
2249 | if (r == NOT_CORE_OPTION) | |
2250 | r = policy_set_config_value(cache->policy, key, value); | |
2251 | ||
2252 | if (r) | |
2253 | DMWARN("bad config value for %s: %s", key, value); | |
2254 | ||
2255 | return r; | |
2256 | } | |
2257 | ||
2258 | static int set_config_values(struct cache *cache, int argc, const char **argv) | |
c6b4fcba JT |
2259 | { |
2260 | int r = 0; | |
2261 | ||
2262 | if (argc & 1) { | |
2263 | DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs."); | |
2264 | return -EINVAL; | |
2265 | } | |
2266 | ||
2267 | while (argc) { | |
2f14f4b5 JT |
2268 | r = set_config_value(cache, argv[0], argv[1]); |
2269 | if (r) | |
2270 | break; | |
c6b4fcba JT |
2271 | |
2272 | argc -= 2; | |
2273 | argv += 2; | |
2274 | } | |
2275 | ||
2276 | return r; | |
2277 | } | |
2278 | ||
2279 | static int create_cache_policy(struct cache *cache, struct cache_args *ca, | |
2280 | char **error) | |
2281 | { | |
4cb3e1db MP |
2282 | struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name, |
2283 | cache->cache_size, | |
2284 | cache->origin_sectors, | |
2285 | cache->sectors_per_block); | |
2286 | if (IS_ERR(p)) { | |
c6b4fcba | 2287 | *error = "Error creating cache's policy"; |
4cb3e1db | 2288 | return PTR_ERR(p); |
c6b4fcba | 2289 | } |
4cb3e1db | 2290 | cache->policy = p; |
c6b4fcba | 2291 | |
2f14f4b5 | 2292 | return 0; |
c6b4fcba JT |
2293 | } |
2294 | ||
08b18451 | 2295 | /* |
2bb812df JT |
2296 | * We want the discard block size to be at least the size of the cache |
2297 | * block size and have no more than 2^14 discard blocks across the origin. | |
08b18451 JT |
2298 | */ |
2299 | #define MAX_DISCARD_BLOCKS (1 << 14) | |
2300 | ||
2301 | static bool too_many_discard_blocks(sector_t discard_block_size, | |
2302 | sector_t origin_size) | |
2303 | { | |
2304 | (void) sector_div(origin_size, discard_block_size); | |
2305 | ||
2306 | return origin_size > MAX_DISCARD_BLOCKS; | |
2307 | } | |
2308 | ||
2309 | static sector_t calculate_discard_block_size(sector_t cache_block_size, | |
2310 | sector_t origin_size) | |
2311 | { | |
2bb812df | 2312 | sector_t discard_block_size = cache_block_size; |
08b18451 JT |
2313 | |
2314 | if (origin_size) | |
2315 | while (too_many_discard_blocks(discard_block_size, origin_size)) | |
2316 | discard_block_size *= 2; | |
2317 | ||
2318 | return discard_block_size; | |
2319 | } | |
2320 | ||
d1d9220c JT |
2321 | static void set_cache_size(struct cache *cache, dm_cblock_t size) |
2322 | { | |
2323 | dm_block_t nr_blocks = from_cblock(size); | |
2324 | ||
2325 | if (nr_blocks > (1 << 20) && cache->cache_size != size) | |
2326 | DMWARN_LIMIT("You have created a cache device with a lot of individual cache blocks (%llu)\n" | |
2327 | "All these mappings can consume a lot of kernel memory, and take some time to read/write.\n" | |
2328 | "Please consider increasing the cache block size to reduce the overall cache block count.", | |
2329 | (unsigned long long) nr_blocks); | |
2330 | ||
2331 | cache->cache_size = size; | |
2332 | } | |
2333 | ||
f8350daf | 2334 | #define DEFAULT_MIGRATION_THRESHOLD 2048 |
c6b4fcba | 2335 | |
c6b4fcba JT |
2336 | static int cache_create(struct cache_args *ca, struct cache **result) |
2337 | { | |
2338 | int r = 0; | |
2339 | char **error = &ca->ti->error; | |
2340 | struct cache *cache; | |
2341 | struct dm_target *ti = ca->ti; | |
2342 | dm_block_t origin_blocks; | |
2343 | struct dm_cache_metadata *cmd; | |
2344 | bool may_format = ca->features.mode == CM_WRITE; | |
2345 | ||
2346 | cache = kzalloc(sizeof(*cache), GFP_KERNEL); | |
2347 | if (!cache) | |
2348 | return -ENOMEM; | |
2349 | ||
2350 | cache->ti = ca->ti; | |
2351 | ti->private = cache; | |
c6b4fcba JT |
2352 | ti->num_flush_bios = 2; |
2353 | ti->flush_supported = true; | |
2354 | ||
2355 | ti->num_discard_bios = 1; | |
2356 | ti->discards_supported = true; | |
2357 | ti->discard_zeroes_data_unsupported = true; | |
2572629a | 2358 | ti->split_discard_bios = false; |
c6b4fcba | 2359 | |
8c5008fa | 2360 | cache->features = ca->features; |
19b0092e | 2361 | ti->per_bio_data_size = get_per_bio_data_size(cache); |
c6b4fcba | 2362 | |
c6b4fcba JT |
2363 | cache->callbacks.congested_fn = cache_is_congested; |
2364 | dm_table_add_target_callbacks(ti->table, &cache->callbacks); | |
2365 | ||
2366 | cache->metadata_dev = ca->metadata_dev; | |
2367 | cache->origin_dev = ca->origin_dev; | |
2368 | cache->cache_dev = ca->cache_dev; | |
2369 | ||
2370 | ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; | |
2371 | ||
2372 | /* FIXME: factor out this whole section */ | |
2373 | origin_blocks = cache->origin_sectors = ca->origin_sectors; | |
414dd67d | 2374 | origin_blocks = block_div(origin_blocks, ca->block_size); |
c6b4fcba JT |
2375 | cache->origin_blocks = to_oblock(origin_blocks); |
2376 | ||
2377 | cache->sectors_per_block = ca->block_size; | |
2378 | if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) { | |
2379 | r = -EINVAL; | |
2380 | goto bad; | |
2381 | } | |
2382 | ||
2383 | if (ca->block_size & (ca->block_size - 1)) { | |
2384 | dm_block_t cache_size = ca->cache_sectors; | |
2385 | ||
2386 | cache->sectors_per_block_shift = -1; | |
414dd67d | 2387 | cache_size = block_div(cache_size, ca->block_size); |
d1d9220c | 2388 | set_cache_size(cache, to_cblock(cache_size)); |
c6b4fcba JT |
2389 | } else { |
2390 | cache->sectors_per_block_shift = __ffs(ca->block_size); | |
d1d9220c | 2391 | set_cache_size(cache, to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift)); |
c6b4fcba JT |
2392 | } |
2393 | ||
2394 | r = create_cache_policy(cache, ca, error); | |
2395 | if (r) | |
2396 | goto bad; | |
2f14f4b5 | 2397 | |
c6b4fcba | 2398 | cache->policy_nr_args = ca->policy_argc; |
2f14f4b5 JT |
2399 | cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD; |
2400 | ||
2401 | r = set_config_values(cache, ca->policy_argc, ca->policy_argv); | |
2402 | if (r) { | |
2403 | *error = "Error setting cache policy's config values"; | |
2404 | goto bad; | |
2405 | } | |
c6b4fcba JT |
2406 | |
2407 | cmd = dm_cache_metadata_open(cache->metadata_dev->bdev, | |
2408 | ca->block_size, may_format, | |
2409 | dm_cache_policy_get_hint_size(cache->policy)); | |
2410 | if (IS_ERR(cmd)) { | |
2411 | *error = "Error creating metadata object"; | |
2412 | r = PTR_ERR(cmd); | |
2413 | goto bad; | |
2414 | } | |
2415 | cache->cmd = cmd; | |
2416 | ||
2ee57d58 JT |
2417 | if (passthrough_mode(&cache->features)) { |
2418 | bool all_clean; | |
2419 | ||
2420 | r = dm_cache_metadata_all_clean(cache->cmd, &all_clean); | |
2421 | if (r) { | |
2422 | *error = "dm_cache_metadata_all_clean() failed"; | |
2423 | goto bad; | |
2424 | } | |
2425 | ||
2426 | if (!all_clean) { | |
2427 | *error = "Cannot enter passthrough mode unless all blocks are clean"; | |
2428 | r = -EINVAL; | |
2429 | goto bad; | |
2430 | } | |
2431 | } | |
2432 | ||
c6b4fcba JT |
2433 | spin_lock_init(&cache->lock); |
2434 | bio_list_init(&cache->deferred_bios); | |
2435 | bio_list_init(&cache->deferred_flush_bios); | |
e2e74d61 | 2436 | bio_list_init(&cache->deferred_writethrough_bios); |
c6b4fcba JT |
2437 | INIT_LIST_HEAD(&cache->quiesced_migrations); |
2438 | INIT_LIST_HEAD(&cache->completed_migrations); | |
2439 | INIT_LIST_HEAD(&cache->need_commit_migrations); | |
a59db676 JT |
2440 | atomic_set(&cache->nr_allocated_migrations, 0); |
2441 | atomic_set(&cache->nr_io_migrations, 0); | |
c6b4fcba JT |
2442 | init_waitqueue_head(&cache->migration_wait); |
2443 | ||
66cb1910 | 2444 | init_waitqueue_head(&cache->quiescing_wait); |
238f8363 | 2445 | atomic_set(&cache->quiescing, 0); |
66cb1910 JT |
2446 | atomic_set(&cache->quiescing_ack, 0); |
2447 | ||
fa4d683a | 2448 | r = -ENOMEM; |
44fa816b | 2449 | atomic_set(&cache->nr_dirty, 0); |
c6b4fcba JT |
2450 | cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size)); |
2451 | if (!cache->dirty_bitset) { | |
2452 | *error = "could not allocate dirty bitset"; | |
2453 | goto bad; | |
2454 | } | |
2455 | clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size)); | |
2456 | ||
08b18451 JT |
2457 | cache->discard_block_size = |
2458 | calculate_discard_block_size(cache->sectors_per_block, | |
2459 | cache->origin_sectors); | |
2572629a JT |
2460 | cache->discard_nr_blocks = to_dblock(dm_sector_div_up(cache->origin_sectors, |
2461 | cache->discard_block_size)); | |
1bad9bc4 | 2462 | cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks)); |
c6b4fcba JT |
2463 | if (!cache->discard_bitset) { |
2464 | *error = "could not allocate discard bitset"; | |
2465 | goto bad; | |
2466 | } | |
1bad9bc4 | 2467 | clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); |
c6b4fcba JT |
2468 | |
2469 | cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); | |
2470 | if (IS_ERR(cache->copier)) { | |
2471 | *error = "could not create kcopyd client"; | |
2472 | r = PTR_ERR(cache->copier); | |
2473 | goto bad; | |
2474 | } | |
2475 | ||
2476 | cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); | |
2477 | if (!cache->wq) { | |
2478 | *error = "could not create workqueue for metadata object"; | |
2479 | goto bad; | |
2480 | } | |
2481 | INIT_WORK(&cache->worker, do_worker); | |
2482 | INIT_DELAYED_WORK(&cache->waker, do_waker); | |
2483 | cache->last_commit_jiffies = jiffies; | |
2484 | ||
a195db2d | 2485 | cache->prison = dm_bio_prison_create(); |
c6b4fcba JT |
2486 | if (!cache->prison) { |
2487 | *error = "could not create bio prison"; | |
2488 | goto bad; | |
2489 | } | |
2490 | ||
2491 | cache->all_io_ds = dm_deferred_set_create(); | |
2492 | if (!cache->all_io_ds) { | |
2493 | *error = "could not create all_io deferred set"; | |
2494 | goto bad; | |
2495 | } | |
2496 | ||
2497 | cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE, | |
2498 | migration_cache); | |
2499 | if (!cache->migration_pool) { | |
2500 | *error = "Error creating cache's migration mempool"; | |
2501 | goto bad; | |
2502 | } | |
2503 | ||
c6b4fcba JT |
2504 | cache->need_tick_bio = true; |
2505 | cache->sized = false; | |
65790ff9 | 2506 | cache->invalidate = false; |
c6b4fcba JT |
2507 | cache->commit_requested = false; |
2508 | cache->loaded_mappings = false; | |
2509 | cache->loaded_discards = false; | |
2510 | ||
2511 | load_stats(cache); | |
2512 | ||
2513 | atomic_set(&cache->stats.demotion, 0); | |
2514 | atomic_set(&cache->stats.promotion, 0); | |
2515 | atomic_set(&cache->stats.copies_avoided, 0); | |
2516 | atomic_set(&cache->stats.cache_cell_clash, 0); | |
2517 | atomic_set(&cache->stats.commit_count, 0); | |
2518 | atomic_set(&cache->stats.discard_count, 0); | |
2519 | ||
65790ff9 JT |
2520 | spin_lock_init(&cache->invalidation_lock); |
2521 | INIT_LIST_HEAD(&cache->invalidation_requests); | |
2522 | ||
c6b4fcba JT |
2523 | *result = cache; |
2524 | return 0; | |
2525 | ||
2526 | bad: | |
2527 | destroy(cache); | |
2528 | return r; | |
2529 | } | |
2530 | ||
2531 | static int copy_ctr_args(struct cache *cache, int argc, const char **argv) | |
2532 | { | |
2533 | unsigned i; | |
2534 | const char **copy; | |
2535 | ||
2536 | copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL); | |
2537 | if (!copy) | |
2538 | return -ENOMEM; | |
2539 | for (i = 0; i < argc; i++) { | |
2540 | copy[i] = kstrdup(argv[i], GFP_KERNEL); | |
2541 | if (!copy[i]) { | |
2542 | while (i--) | |
2543 | kfree(copy[i]); | |
2544 | kfree(copy); | |
2545 | return -ENOMEM; | |
2546 | } | |
2547 | } | |
2548 | ||
2549 | cache->nr_ctr_args = argc; | |
2550 | cache->ctr_args = copy; | |
2551 | ||
2552 | return 0; | |
2553 | } | |
2554 | ||
2555 | static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
2556 | { | |
2557 | int r = -EINVAL; | |
2558 | struct cache_args *ca; | |
2559 | struct cache *cache = NULL; | |
2560 | ||
2561 | ca = kzalloc(sizeof(*ca), GFP_KERNEL); | |
2562 | if (!ca) { | |
2563 | ti->error = "Error allocating memory for cache"; | |
2564 | return -ENOMEM; | |
2565 | } | |
2566 | ca->ti = ti; | |
2567 | ||
2568 | r = parse_cache_args(ca, argc, argv, &ti->error); | |
2569 | if (r) | |
2570 | goto out; | |
2571 | ||
2572 | r = cache_create(ca, &cache); | |
617a0b89 HM |
2573 | if (r) |
2574 | goto out; | |
c6b4fcba JT |
2575 | |
2576 | r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3); | |
2577 | if (r) { | |
2578 | destroy(cache); | |
2579 | goto out; | |
2580 | } | |
2581 | ||
2582 | ti->private = cache; | |
2583 | ||
2584 | out: | |
2585 | destroy_cache_args(ca); | |
2586 | return r; | |
2587 | } | |
2588 | ||
8c081b52 | 2589 | static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell **cell) |
c6b4fcba | 2590 | { |
c6b4fcba JT |
2591 | int r; |
2592 | dm_oblock_t block = get_bio_block(cache, bio); | |
19b0092e | 2593 | size_t pb_data_size = get_per_bio_data_size(cache); |
c6b4fcba JT |
2594 | bool can_migrate = false; |
2595 | bool discarded_block; | |
c6b4fcba | 2596 | struct policy_result lookup_result; |
e893fba9 | 2597 | struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size); |
c6b4fcba | 2598 | |
e893fba9 | 2599 | if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) { |
c6b4fcba JT |
2600 | /* |
2601 | * This can only occur if the io goes to a partial block at | |
2602 | * the end of the origin device. We don't cache these. | |
2603 | * Just remap to the origin and carry on. | |
2604 | */ | |
e893fba9 | 2605 | remap_to_origin(cache, bio); |
c6b4fcba JT |
2606 | return DM_MAPIO_REMAPPED; |
2607 | } | |
2608 | ||
c6b4fcba JT |
2609 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) { |
2610 | defer_bio(cache, bio); | |
2611 | return DM_MAPIO_SUBMITTED; | |
2612 | } | |
2613 | ||
2614 | /* | |
2615 | * Check to see if that block is currently migrating. | |
2616 | */ | |
8c081b52 JT |
2617 | *cell = alloc_prison_cell(cache); |
2618 | if (!*cell) { | |
c6b4fcba JT |
2619 | defer_bio(cache, bio); |
2620 | return DM_MAPIO_SUBMITTED; | |
2621 | } | |
2622 | ||
8c081b52 | 2623 | r = bio_detain(cache, block, bio, *cell, |
c6b4fcba | 2624 | (cell_free_fn) free_prison_cell, |
8c081b52 | 2625 | cache, cell); |
c6b4fcba JT |
2626 | if (r) { |
2627 | if (r < 0) | |
2628 | defer_bio(cache, bio); | |
2629 | ||
2630 | return DM_MAPIO_SUBMITTED; | |
2631 | } | |
2632 | ||
2633 | discarded_block = is_discarded_oblock(cache, block); | |
2634 | ||
2635 | r = policy_map(cache->policy, block, false, can_migrate, discarded_block, | |
2636 | bio, &lookup_result); | |
2637 | if (r == -EWOULDBLOCK) { | |
8c081b52 | 2638 | cell_defer(cache, *cell, true); |
c6b4fcba JT |
2639 | return DM_MAPIO_SUBMITTED; |
2640 | ||
2641 | } else if (r) { | |
2642 | DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r); | |
8c081b52 | 2643 | cell_defer(cache, *cell, false); |
c6b4fcba JT |
2644 | bio_io_error(bio); |
2645 | return DM_MAPIO_SUBMITTED; | |
2646 | } | |
2647 | ||
2ee57d58 | 2648 | r = DM_MAPIO_REMAPPED; |
c6b4fcba JT |
2649 | switch (lookup_result.op) { |
2650 | case POLICY_HIT: | |
2ee57d58 JT |
2651 | if (passthrough_mode(&cache->features)) { |
2652 | if (bio_data_dir(bio) == WRITE) { | |
2653 | /* | |
2654 | * We need to invalidate this block, so | |
2655 | * defer for the worker thread. | |
2656 | */ | |
8c081b52 | 2657 | cell_defer(cache, *cell, true); |
2ee57d58 JT |
2658 | r = DM_MAPIO_SUBMITTED; |
2659 | ||
2660 | } else { | |
2ee57d58 JT |
2661 | inc_miss_counter(cache, bio); |
2662 | remap_to_origin_clear_discard(cache, bio, block); | |
2ee57d58 | 2663 | } |
c6b4fcba | 2664 | |
2ee57d58 JT |
2665 | } else { |
2666 | inc_hit_counter(cache, bio); | |
2ee57d58 JT |
2667 | if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) && |
2668 | !is_dirty(cache, lookup_result.cblock)) | |
2669 | remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); | |
2670 | else | |
2671 | remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); | |
2ee57d58 | 2672 | } |
c6b4fcba JT |
2673 | break; |
2674 | ||
2675 | case POLICY_MISS: | |
2676 | inc_miss_counter(cache, bio); | |
c6b4fcba JT |
2677 | if (pb->req_nr != 0) { |
2678 | /* | |
2679 | * This is a duplicate writethrough io that is no | |
2680 | * longer needed because the block has been demoted. | |
2681 | */ | |
2682 | bio_endio(bio, 0); | |
8c081b52 JT |
2683 | cell_defer(cache, *cell, false); |
2684 | r = DM_MAPIO_SUBMITTED; | |
2685 | ||
2686 | } else | |
c6b4fcba | 2687 | remap_to_origin_clear_discard(cache, bio, block); |
8c081b52 | 2688 | |
c6b4fcba JT |
2689 | break; |
2690 | ||
2691 | default: | |
2692 | DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__, | |
2693 | (unsigned) lookup_result.op); | |
8c081b52 | 2694 | cell_defer(cache, *cell, false); |
c6b4fcba | 2695 | bio_io_error(bio); |
2ee57d58 | 2696 | r = DM_MAPIO_SUBMITTED; |
c6b4fcba JT |
2697 | } |
2698 | ||
2ee57d58 | 2699 | return r; |
c6b4fcba JT |
2700 | } |
2701 | ||
8c081b52 JT |
2702 | static int cache_map(struct dm_target *ti, struct bio *bio) |
2703 | { | |
2704 | int r; | |
f824a2af | 2705 | struct dm_bio_prison_cell *cell = NULL; |
8c081b52 JT |
2706 | struct cache *cache = ti->private; |
2707 | ||
2708 | r = __cache_map(cache, bio, &cell); | |
f824a2af | 2709 | if (r == DM_MAPIO_REMAPPED && cell) { |
8c081b52 JT |
2710 | inc_ds(cache, bio, cell); |
2711 | cell_defer(cache, cell, false); | |
2712 | } | |
2713 | ||
2714 | return r; | |
2715 | } | |
2716 | ||
c6b4fcba JT |
2717 | static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) |
2718 | { | |
2719 | struct cache *cache = ti->private; | |
2720 | unsigned long flags; | |
19b0092e MS |
2721 | size_t pb_data_size = get_per_bio_data_size(cache); |
2722 | struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); | |
c6b4fcba JT |
2723 | |
2724 | if (pb->tick) { | |
2725 | policy_tick(cache->policy); | |
2726 | ||
2727 | spin_lock_irqsave(&cache->lock, flags); | |
2728 | cache->need_tick_bio = true; | |
2729 | spin_unlock_irqrestore(&cache->lock, flags); | |
2730 | } | |
2731 | ||
2732 | check_for_quiesced_migrations(cache, pb); | |
2733 | ||
2734 | return 0; | |
2735 | } | |
2736 | ||
2737 | static int write_dirty_bitset(struct cache *cache) | |
2738 | { | |
2739 | unsigned i, r; | |
2740 | ||
2741 | for (i = 0; i < from_cblock(cache->cache_size); i++) { | |
2742 | r = dm_cache_set_dirty(cache->cmd, to_cblock(i), | |
2743 | is_dirty(cache, to_cblock(i))); | |
2744 | if (r) | |
2745 | return r; | |
2746 | } | |
2747 | ||
2748 | return 0; | |
2749 | } | |
2750 | ||
2751 | static int write_discard_bitset(struct cache *cache) | |
2752 | { | |
2753 | unsigned i, r; | |
2754 | ||
1bad9bc4 JT |
2755 | r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size, |
2756 | cache->discard_nr_blocks); | |
c6b4fcba JT |
2757 | if (r) { |
2758 | DMERR("could not resize on-disk discard bitset"); | |
2759 | return r; | |
2760 | } | |
2761 | ||
1bad9bc4 JT |
2762 | for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) { |
2763 | r = dm_cache_set_discard(cache->cmd, to_dblock(i), | |
2764 | is_discarded(cache, to_dblock(i))); | |
c6b4fcba JT |
2765 | if (r) |
2766 | return r; | |
2767 | } | |
2768 | ||
2769 | return 0; | |
2770 | } | |
2771 | ||
c6b4fcba JT |
2772 | /* |
2773 | * returns true on success | |
2774 | */ | |
2775 | static bool sync_metadata(struct cache *cache) | |
2776 | { | |
2777 | int r1, r2, r3, r4; | |
2778 | ||
2779 | r1 = write_dirty_bitset(cache); | |
2780 | if (r1) | |
2781 | DMERR("could not write dirty bitset"); | |
2782 | ||
2783 | r2 = write_discard_bitset(cache); | |
2784 | if (r2) | |
2785 | DMERR("could not write discard bitset"); | |
2786 | ||
2787 | save_stats(cache); | |
2788 | ||
0596661f | 2789 | r3 = dm_cache_write_hints(cache->cmd, cache->policy); |
c6b4fcba JT |
2790 | if (r3) |
2791 | DMERR("could not write hints"); | |
2792 | ||
2793 | /* | |
2794 | * If writing the above metadata failed, we still commit, but don't | |
2795 | * set the clean shutdown flag. This will effectively force every | |
2796 | * dirty bit to be set on reload. | |
2797 | */ | |
2798 | r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3); | |
2799 | if (r4) | |
2800 | DMERR("could not write cache metadata. Data loss may occur."); | |
2801 | ||
2802 | return !r1 && !r2 && !r3 && !r4; | |
2803 | } | |
2804 | ||
2805 | static void cache_postsuspend(struct dm_target *ti) | |
2806 | { | |
2807 | struct cache *cache = ti->private; | |
2808 | ||
2809 | start_quiescing(cache); | |
2810 | wait_for_migrations(cache); | |
2811 | stop_worker(cache); | |
2812 | requeue_deferred_io(cache); | |
2813 | stop_quiescing(cache); | |
2814 | ||
2815 | (void) sync_metadata(cache); | |
2816 | } | |
2817 | ||
2818 | static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, | |
2819 | bool dirty, uint32_t hint, bool hint_valid) | |
2820 | { | |
2821 | int r; | |
2822 | struct cache *cache = context; | |
2823 | ||
2824 | r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid); | |
2825 | if (r) | |
2826 | return r; | |
2827 | ||
2828 | if (dirty) | |
2829 | set_dirty(cache, oblock, cblock); | |
2830 | else | |
2831 | clear_dirty(cache, oblock, cblock); | |
2832 | ||
2833 | return 0; | |
2834 | } | |
2835 | ||
3e2e1c30 JT |
2836 | /* |
2837 | * The discard block size in the on disk metadata is not | |
2838 | * neccessarily the same as we're currently using. So we have to | |
2839 | * be careful to only set the discarded attribute if we know it | |
2840 | * covers a complete block of the new size. | |
2841 | */ | |
2842 | struct discard_load_info { | |
2843 | struct cache *cache; | |
2844 | ||
2845 | /* | |
2846 | * These blocks are sized using the on disk dblock size, rather | |
2847 | * than the current one. | |
2848 | */ | |
2849 | dm_block_t block_size; | |
2850 | dm_block_t discard_begin, discard_end; | |
2851 | }; | |
2852 | ||
2853 | static void discard_load_info_init(struct cache *cache, | |
2854 | struct discard_load_info *li) | |
2855 | { | |
2856 | li->cache = cache; | |
2857 | li->discard_begin = li->discard_end = 0; | |
2858 | } | |
2859 | ||
2860 | static void set_discard_range(struct discard_load_info *li) | |
2861 | { | |
2862 | sector_t b, e; | |
2863 | ||
2864 | if (li->discard_begin == li->discard_end) | |
2865 | return; | |
2866 | ||
2867 | /* | |
2868 | * Convert to sectors. | |
2869 | */ | |
2870 | b = li->discard_begin * li->block_size; | |
2871 | e = li->discard_end * li->block_size; | |
2872 | ||
2873 | /* | |
2874 | * Then convert back to the current dblock size. | |
2875 | */ | |
2876 | b = dm_sector_div_up(b, li->cache->discard_block_size); | |
2877 | sector_div(e, li->cache->discard_block_size); | |
2878 | ||
2879 | /* | |
2880 | * The origin may have shrunk, so we need to check we're still in | |
2881 | * bounds. | |
2882 | */ | |
2883 | if (e > from_dblock(li->cache->discard_nr_blocks)) | |
2884 | e = from_dblock(li->cache->discard_nr_blocks); | |
2885 | ||
2886 | for (; b < e; b++) | |
2887 | set_discard(li->cache, to_dblock(b)); | |
2888 | } | |
2889 | ||
c6b4fcba | 2890 | static int load_discard(void *context, sector_t discard_block_size, |
1bad9bc4 | 2891 | dm_dblock_t dblock, bool discard) |
c6b4fcba | 2892 | { |
3e2e1c30 | 2893 | struct discard_load_info *li = context; |
c6b4fcba | 2894 | |
3e2e1c30 | 2895 | li->block_size = discard_block_size; |
1bad9bc4 | 2896 | |
3e2e1c30 JT |
2897 | if (discard) { |
2898 | if (from_dblock(dblock) == li->discard_end) | |
2899 | /* | |
2900 | * We're already in a discard range, just extend it. | |
2901 | */ | |
2902 | li->discard_end = li->discard_end + 1ULL; | |
2903 | ||
2904 | else { | |
2905 | /* | |
2906 | * Emit the old range and start a new one. | |
2907 | */ | |
2908 | set_discard_range(li); | |
2909 | li->discard_begin = from_dblock(dblock); | |
2910 | li->discard_end = li->discard_begin + 1ULL; | |
2911 | } | |
2912 | } else { | |
2913 | set_discard_range(li); | |
2914 | li->discard_begin = li->discard_end = 0; | |
2915 | } | |
c6b4fcba JT |
2916 | |
2917 | return 0; | |
2918 | } | |
2919 | ||
f494a9c6 JT |
2920 | static dm_cblock_t get_cache_dev_size(struct cache *cache) |
2921 | { | |
2922 | sector_t size = get_dev_size(cache->cache_dev); | |
2923 | (void) sector_div(size, cache->sectors_per_block); | |
2924 | return to_cblock(size); | |
2925 | } | |
2926 | ||
2927 | static bool can_resize(struct cache *cache, dm_cblock_t new_size) | |
2928 | { | |
2929 | if (from_cblock(new_size) > from_cblock(cache->cache_size)) | |
2930 | return true; | |
2931 | ||
2932 | /* | |
2933 | * We can't drop a dirty block when shrinking the cache. | |
2934 | */ | |
2935 | while (from_cblock(new_size) < from_cblock(cache->cache_size)) { | |
2936 | new_size = to_cblock(from_cblock(new_size) + 1); | |
2937 | if (is_dirty(cache, new_size)) { | |
2938 | DMERR("unable to shrink cache; cache block %llu is dirty", | |
2939 | (unsigned long long) from_cblock(new_size)); | |
2940 | return false; | |
2941 | } | |
2942 | } | |
2943 | ||
2944 | return true; | |
2945 | } | |
2946 | ||
2947 | static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size) | |
2948 | { | |
2949 | int r; | |
2950 | ||
08844800 | 2951 | r = dm_cache_resize(cache->cmd, new_size); |
f494a9c6 JT |
2952 | if (r) { |
2953 | DMERR("could not resize cache metadata"); | |
2954 | return r; | |
2955 | } | |
2956 | ||
d1d9220c | 2957 | set_cache_size(cache, new_size); |
f494a9c6 JT |
2958 | |
2959 | return 0; | |
2960 | } | |
2961 | ||
c6b4fcba JT |
2962 | static int cache_preresume(struct dm_target *ti) |
2963 | { | |
2964 | int r = 0; | |
2965 | struct cache *cache = ti->private; | |
f494a9c6 | 2966 | dm_cblock_t csize = get_cache_dev_size(cache); |
c6b4fcba JT |
2967 | |
2968 | /* | |
2969 | * Check to see if the cache has resized. | |
2970 | */ | |
f494a9c6 JT |
2971 | if (!cache->sized) { |
2972 | r = resize_cache_dev(cache, csize); | |
2973 | if (r) | |
c6b4fcba | 2974 | return r; |
c6b4fcba JT |
2975 | |
2976 | cache->sized = true; | |
f494a9c6 JT |
2977 | |
2978 | } else if (csize != cache->cache_size) { | |
2979 | if (!can_resize(cache, csize)) | |
2980 | return -EINVAL; | |
2981 | ||
2982 | r = resize_cache_dev(cache, csize); | |
2983 | if (r) | |
2984 | return r; | |
c6b4fcba JT |
2985 | } |
2986 | ||
2987 | if (!cache->loaded_mappings) { | |
ea2dd8c1 | 2988 | r = dm_cache_load_mappings(cache->cmd, cache->policy, |
c6b4fcba JT |
2989 | load_mapping, cache); |
2990 | if (r) { | |
2991 | DMERR("could not load cache mappings"); | |
2992 | return r; | |
2993 | } | |
2994 | ||
2995 | cache->loaded_mappings = true; | |
2996 | } | |
2997 | ||
2998 | if (!cache->loaded_discards) { | |
3e2e1c30 JT |
2999 | struct discard_load_info li; |
3000 | ||
3001 | /* | |
3002 | * The discard bitset could have been resized, or the | |
3003 | * discard block size changed. To be safe we start by | |
3004 | * setting every dblock to not discarded. | |
3005 | */ | |
3006 | clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); | |
3007 | ||
3008 | discard_load_info_init(cache, &li); | |
3009 | r = dm_cache_load_discards(cache->cmd, load_discard, &li); | |
c6b4fcba JT |
3010 | if (r) { |
3011 | DMERR("could not load origin discards"); | |
3012 | return r; | |
3013 | } | |
3e2e1c30 | 3014 | set_discard_range(&li); |
c6b4fcba JT |
3015 | |
3016 | cache->loaded_discards = true; | |
3017 | } | |
3018 | ||
3019 | return r; | |
3020 | } | |
3021 | ||
3022 | static void cache_resume(struct dm_target *ti) | |
3023 | { | |
3024 | struct cache *cache = ti->private; | |
3025 | ||
3026 | cache->need_tick_bio = true; | |
3027 | do_waker(&cache->waker.work); | |
3028 | } | |
3029 | ||
3030 | /* | |
3031 | * Status format: | |
3032 | * | |
6a388618 MS |
3033 | * <metadata block size> <#used metadata blocks>/<#total metadata blocks> |
3034 | * <cache block size> <#used cache blocks>/<#total cache blocks> | |
c6b4fcba | 3035 | * <#read hits> <#read misses> <#write hits> <#write misses> |
6a388618 | 3036 | * <#demotions> <#promotions> <#dirty> |
c6b4fcba JT |
3037 | * <#features> <features>* |
3038 | * <#core args> <core args> | |
2e68c4e6 | 3039 | * <policy name> <#policy args> <policy args>* |
c6b4fcba JT |
3040 | */ |
3041 | static void cache_status(struct dm_target *ti, status_type_t type, | |
3042 | unsigned status_flags, char *result, unsigned maxlen) | |
3043 | { | |
3044 | int r = 0; | |
3045 | unsigned i; | |
3046 | ssize_t sz = 0; | |
3047 | dm_block_t nr_free_blocks_metadata = 0; | |
3048 | dm_block_t nr_blocks_metadata = 0; | |
3049 | char buf[BDEVNAME_SIZE]; | |
3050 | struct cache *cache = ti->private; | |
3051 | dm_cblock_t residency; | |
3052 | ||
3053 | switch (type) { | |
3054 | case STATUSTYPE_INFO: | |
3055 | /* Commit to ensure statistics aren't out-of-date */ | |
3056 | if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) { | |
3057 | r = dm_cache_commit(cache->cmd, false); | |
3058 | if (r) | |
3059 | DMERR("could not commit metadata for accurate status"); | |
3060 | } | |
3061 | ||
3062 | r = dm_cache_get_free_metadata_block_count(cache->cmd, | |
3063 | &nr_free_blocks_metadata); | |
3064 | if (r) { | |
3065 | DMERR("could not get metadata free block count"); | |
3066 | goto err; | |
3067 | } | |
3068 | ||
3069 | r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata); | |
3070 | if (r) { | |
3071 | DMERR("could not get metadata device size"); | |
3072 | goto err; | |
3073 | } | |
3074 | ||
3075 | residency = policy_residency(cache->policy); | |
3076 | ||
44fa816b | 3077 | DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %lu ", |
895b47d7 | 3078 | (unsigned)DM_CACHE_METADATA_BLOCK_SIZE, |
c6b4fcba JT |
3079 | (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), |
3080 | (unsigned long long)nr_blocks_metadata, | |
6a388618 MS |
3081 | cache->sectors_per_block, |
3082 | (unsigned long long) from_cblock(residency), | |
3083 | (unsigned long long) from_cblock(cache->cache_size), | |
c6b4fcba JT |
3084 | (unsigned) atomic_read(&cache->stats.read_hit), |
3085 | (unsigned) atomic_read(&cache->stats.read_miss), | |
3086 | (unsigned) atomic_read(&cache->stats.write_hit), | |
3087 | (unsigned) atomic_read(&cache->stats.write_miss), | |
3088 | (unsigned) atomic_read(&cache->stats.demotion), | |
3089 | (unsigned) atomic_read(&cache->stats.promotion), | |
44fa816b | 3090 | (unsigned long) atomic_read(&cache->nr_dirty)); |
c6b4fcba | 3091 | |
2ee57d58 | 3092 | if (writethrough_mode(&cache->features)) |
c6b4fcba | 3093 | DMEMIT("1 writethrough "); |
2ee57d58 JT |
3094 | |
3095 | else if (passthrough_mode(&cache->features)) | |
3096 | DMEMIT("1 passthrough "); | |
3097 | ||
3098 | else if (writeback_mode(&cache->features)) | |
3099 | DMEMIT("1 writeback "); | |
3100 | ||
3101 | else { | |
3102 | DMERR("internal error: unknown io mode: %d", (int) cache->features.io_mode); | |
3103 | goto err; | |
3104 | } | |
c6b4fcba JT |
3105 | |
3106 | DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold); | |
2e68c4e6 MS |
3107 | |
3108 | DMEMIT("%s ", dm_cache_policy_get_name(cache->policy)); | |
c6b4fcba JT |
3109 | if (sz < maxlen) { |
3110 | r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz); | |
3111 | if (r) | |
3112 | DMERR("policy_emit_config_values returned %d", r); | |
3113 | } | |
3114 | ||
3115 | break; | |
3116 | ||
3117 | case STATUSTYPE_TABLE: | |
3118 | format_dev_t(buf, cache->metadata_dev->bdev->bd_dev); | |
3119 | DMEMIT("%s ", buf); | |
3120 | format_dev_t(buf, cache->cache_dev->bdev->bd_dev); | |
3121 | DMEMIT("%s ", buf); | |
3122 | format_dev_t(buf, cache->origin_dev->bdev->bd_dev); | |
3123 | DMEMIT("%s", buf); | |
3124 | ||
3125 | for (i = 0; i < cache->nr_ctr_args - 1; i++) | |
3126 | DMEMIT(" %s", cache->ctr_args[i]); | |
3127 | if (cache->nr_ctr_args) | |
3128 | DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]); | |
3129 | } | |
3130 | ||
3131 | return; | |
3132 | ||
3133 | err: | |
3134 | DMEMIT("Error"); | |
3135 | } | |
3136 | ||
c6b4fcba | 3137 | /* |
65790ff9 JT |
3138 | * A cache block range can take two forms: |
3139 | * | |
3140 | * i) A single cblock, eg. '3456' | |
3141 | * ii) A begin and end cblock with dots between, eg. 123-234 | |
3142 | */ | |
3143 | static int parse_cblock_range(struct cache *cache, const char *str, | |
3144 | struct cblock_range *result) | |
3145 | { | |
3146 | char dummy; | |
3147 | uint64_t b, e; | |
3148 | int r; | |
3149 | ||
3150 | /* | |
3151 | * Try and parse form (ii) first. | |
3152 | */ | |
3153 | r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); | |
3154 | if (r < 0) | |
3155 | return r; | |
3156 | ||
3157 | if (r == 2) { | |
3158 | result->begin = to_cblock(b); | |
3159 | result->end = to_cblock(e); | |
3160 | return 0; | |
3161 | } | |
3162 | ||
3163 | /* | |
3164 | * That didn't work, try form (i). | |
3165 | */ | |
3166 | r = sscanf(str, "%llu%c", &b, &dummy); | |
3167 | if (r < 0) | |
3168 | return r; | |
3169 | ||
3170 | if (r == 1) { | |
3171 | result->begin = to_cblock(b); | |
3172 | result->end = to_cblock(from_cblock(result->begin) + 1u); | |
3173 | return 0; | |
3174 | } | |
3175 | ||
3176 | DMERR("invalid cblock range '%s'", str); | |
3177 | return -EINVAL; | |
3178 | } | |
3179 | ||
3180 | static int validate_cblock_range(struct cache *cache, struct cblock_range *range) | |
3181 | { | |
3182 | uint64_t b = from_cblock(range->begin); | |
3183 | uint64_t e = from_cblock(range->end); | |
3184 | uint64_t n = from_cblock(cache->cache_size); | |
3185 | ||
3186 | if (b >= n) { | |
3187 | DMERR("begin cblock out of range: %llu >= %llu", b, n); | |
3188 | return -EINVAL; | |
3189 | } | |
3190 | ||
3191 | if (e > n) { | |
3192 | DMERR("end cblock out of range: %llu > %llu", e, n); | |
3193 | return -EINVAL; | |
3194 | } | |
3195 | ||
3196 | if (b >= e) { | |
3197 | DMERR("invalid cblock range: %llu >= %llu", b, e); | |
3198 | return -EINVAL; | |
3199 | } | |
3200 | ||
3201 | return 0; | |
3202 | } | |
3203 | ||
3204 | static int request_invalidation(struct cache *cache, struct cblock_range *range) | |
3205 | { | |
3206 | struct invalidation_request req; | |
3207 | ||
3208 | INIT_LIST_HEAD(&req.list); | |
3209 | req.cblocks = range; | |
3210 | atomic_set(&req.complete, 0); | |
3211 | req.err = 0; | |
3212 | init_waitqueue_head(&req.result_wait); | |
3213 | ||
3214 | spin_lock(&cache->invalidation_lock); | |
3215 | list_add(&req.list, &cache->invalidation_requests); | |
3216 | spin_unlock(&cache->invalidation_lock); | |
3217 | wake_worker(cache); | |
3218 | ||
3219 | wait_event(req.result_wait, atomic_read(&req.complete)); | |
3220 | return req.err; | |
3221 | } | |
3222 | ||
3223 | static int process_invalidate_cblocks_message(struct cache *cache, unsigned count, | |
3224 | const char **cblock_ranges) | |
3225 | { | |
3226 | int r = 0; | |
3227 | unsigned i; | |
3228 | struct cblock_range range; | |
3229 | ||
3230 | if (!passthrough_mode(&cache->features)) { | |
3231 | DMERR("cache has to be in passthrough mode for invalidation"); | |
3232 | return -EPERM; | |
3233 | } | |
3234 | ||
3235 | for (i = 0; i < count; i++) { | |
3236 | r = parse_cblock_range(cache, cblock_ranges[i], &range); | |
3237 | if (r) | |
3238 | break; | |
3239 | ||
3240 | r = validate_cblock_range(cache, &range); | |
3241 | if (r) | |
3242 | break; | |
3243 | ||
3244 | /* | |
3245 | * Pass begin and end origin blocks to the worker and wake it. | |
3246 | */ | |
3247 | r = request_invalidation(cache, &range); | |
3248 | if (r) | |
3249 | break; | |
3250 | } | |
3251 | ||
3252 | return r; | |
3253 | } | |
3254 | ||
3255 | /* | |
3256 | * Supports | |
3257 | * "<key> <value>" | |
3258 | * and | |
3259 | * "invalidate_cblocks [(<begin>)|(<begin>-<end>)]* | |
c6b4fcba JT |
3260 | * |
3261 | * The key migration_threshold is supported by the cache target core. | |
3262 | */ | |
3263 | static int cache_message(struct dm_target *ti, unsigned argc, char **argv) | |
3264 | { | |
c6b4fcba JT |
3265 | struct cache *cache = ti->private; |
3266 | ||
65790ff9 JT |
3267 | if (!argc) |
3268 | return -EINVAL; | |
3269 | ||
7b6b2bc9 | 3270 | if (!strcasecmp(argv[0], "invalidate_cblocks")) |
65790ff9 JT |
3271 | return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1); |
3272 | ||
c6b4fcba JT |
3273 | if (argc != 2) |
3274 | return -EINVAL; | |
3275 | ||
2f14f4b5 | 3276 | return set_config_value(cache, argv[0], argv[1]); |
c6b4fcba JT |
3277 | } |
3278 | ||
3279 | static int cache_iterate_devices(struct dm_target *ti, | |
3280 | iterate_devices_callout_fn fn, void *data) | |
3281 | { | |
3282 | int r = 0; | |
3283 | struct cache *cache = ti->private; | |
3284 | ||
3285 | r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data); | |
3286 | if (!r) | |
3287 | r = fn(ti, cache->origin_dev, 0, ti->len, data); | |
3288 | ||
3289 | return r; | |
3290 | } | |
3291 | ||
3292 | /* | |
3293 | * We assume I/O is going to the origin (which is the volume | |
3294 | * more likely to have restrictions e.g. by being striped). | |
3295 | * (Looking up the exact location of the data would be expensive | |
3296 | * and could always be out of date by the time the bio is submitted.) | |
3297 | */ | |
3298 | static int cache_bvec_merge(struct dm_target *ti, | |
3299 | struct bvec_merge_data *bvm, | |
3300 | struct bio_vec *biovec, int max_size) | |
3301 | { | |
3302 | struct cache *cache = ti->private; | |
3303 | struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev); | |
3304 | ||
3305 | if (!q->merge_bvec_fn) | |
3306 | return max_size; | |
3307 | ||
3308 | bvm->bi_bdev = cache->origin_dev->bdev; | |
3309 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
3310 | } | |
3311 | ||
3312 | static void set_discard_limits(struct cache *cache, struct queue_limits *limits) | |
3313 | { | |
3314 | /* | |
3315 | * FIXME: these limits may be incompatible with the cache device | |
3316 | */ | |
7ae34e77 JT |
3317 | limits->max_discard_sectors = min_t(sector_t, cache->discard_block_size * 1024, |
3318 | cache->origin_sectors); | |
1bad9bc4 | 3319 | limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT; |
c6b4fcba JT |
3320 | } |
3321 | ||
3322 | static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
3323 | { | |
3324 | struct cache *cache = ti->private; | |
f6109372 | 3325 | uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; |
c6b4fcba | 3326 | |
f6109372 MS |
3327 | /* |
3328 | * If the system-determined stacked limits are compatible with the | |
3329 | * cache's blocksize (io_opt is a factor) do not override them. | |
3330 | */ | |
3331 | if (io_opt_sectors < cache->sectors_per_block || | |
3332 | do_div(io_opt_sectors, cache->sectors_per_block)) { | |
b0246530 | 3333 | blk_limits_io_min(limits, cache->sectors_per_block << SECTOR_SHIFT); |
f6109372 MS |
3334 | blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT); |
3335 | } | |
c6b4fcba JT |
3336 | set_discard_limits(cache, limits); |
3337 | } | |
3338 | ||
3339 | /*----------------------------------------------------------------*/ | |
3340 | ||
3341 | static struct target_type cache_target = { | |
3342 | .name = "cache", | |
7ae34e77 | 3343 | .version = {1, 6, 0}, |
c6b4fcba JT |
3344 | .module = THIS_MODULE, |
3345 | .ctr = cache_ctr, | |
3346 | .dtr = cache_dtr, | |
3347 | .map = cache_map, | |
3348 | .end_io = cache_end_io, | |
3349 | .postsuspend = cache_postsuspend, | |
3350 | .preresume = cache_preresume, | |
3351 | .resume = cache_resume, | |
3352 | .status = cache_status, | |
3353 | .message = cache_message, | |
3354 | .iterate_devices = cache_iterate_devices, | |
3355 | .merge = cache_bvec_merge, | |
3356 | .io_hints = cache_io_hints, | |
3357 | }; | |
3358 | ||
3359 | static int __init dm_cache_init(void) | |
3360 | { | |
3361 | int r; | |
3362 | ||
3363 | r = dm_register_target(&cache_target); | |
3364 | if (r) { | |
3365 | DMERR("cache target registration failed: %d", r); | |
3366 | return r; | |
3367 | } | |
3368 | ||
3369 | migration_cache = KMEM_CACHE(dm_cache_migration, 0); | |
3370 | if (!migration_cache) { | |
3371 | dm_unregister_target(&cache_target); | |
3372 | return -ENOMEM; | |
3373 | } | |
3374 | ||
3375 | return 0; | |
3376 | } | |
3377 | ||
3378 | static void __exit dm_cache_exit(void) | |
3379 | { | |
3380 | dm_unregister_target(&cache_target); | |
3381 | kmem_cache_destroy(migration_cache); | |
3382 | } | |
3383 | ||
3384 | module_init(dm_cache_init); | |
3385 | module_exit(dm_cache_exit); | |
3386 | ||
3387 | MODULE_DESCRIPTION(DM_NAME " cache target"); | |
3388 | MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>"); | |
3389 | MODULE_LICENSE("GPL"); |