blob: a54108e1e233136ab6072d599b5faea84f40b757 [file] [log] [blame]
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001/*
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"
Darrick J. Wongb844fe62013-04-05 15:36:32 +01009#include "dm-bio-record.h"
Joe Thornberc6b4fcb2013-03-01 22:45:51 +000010#include "dm-cache-metadata.h"
11
12#include <linux/dm-io.h>
13#include <linux/dm-kcopyd.h>
14#include <linux/init.h>
15#include <linux/mempool.h>
16#include <linux/module.h>
17#include <linux/slab.h>
18#include <linux/vmalloc.h>
19
20#define DM_MSG_PREFIX "cache"
21
22DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle,
23 "A percentage of time allocated for copying to and/or from cache");
24
25/*----------------------------------------------------------------*/
26
27/*
28 * Glossary:
29 *
30 * oblock: index of an origin block
31 * cblock: index of a cache block
32 * promotion: movement of a block from origin to cache
33 * demotion: movement of a block from cache to origin
34 * migration: movement of a block between the origin and cache device,
35 * either direction
36 */
37
38/*----------------------------------------------------------------*/
39
40static size_t bitset_size_in_bytes(unsigned nr_entries)
41{
42 return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG);
43}
44
45static unsigned long *alloc_bitset(unsigned nr_entries)
46{
47 size_t s = bitset_size_in_bytes(nr_entries);
48 return vzalloc(s);
49}
50
51static void clear_bitset(void *bitset, unsigned nr_entries)
52{
53 size_t s = bitset_size_in_bytes(nr_entries);
54 memset(bitset, 0, s);
55}
56
57static void free_bitset(unsigned long *bits)
58{
59 vfree(bits);
60}
61
62/*----------------------------------------------------------------*/
63
Joe Thornberc9d28d52013-10-31 13:55:48 -040064/*
65 * There are a couple of places where we let a bio run, but want to do some
66 * work before calling its endio function. We do this by temporarily
67 * changing the endio fn.
68 */
69struct dm_hook_info {
70 bio_end_io_t *bi_end_io;
71 void *bi_private;
72};
73
74static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio,
75 bio_end_io_t *bi_end_io, void *bi_private)
76{
77 h->bi_end_io = bio->bi_end_io;
78 h->bi_private = bio->bi_private;
79
80 bio->bi_end_io = bi_end_io;
81 bio->bi_private = bi_private;
82}
83
84static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio)
85{
86 bio->bi_end_io = h->bi_end_io;
87 bio->bi_private = h->bi_private;
Mike Snitzer8d307262013-12-03 19:16:04 -070088
89 /*
90 * Must bump bi_remaining to allow bio to complete with
91 * restored bi_end_io.
92 */
93 atomic_inc(&bio->bi_remaining);
Joe Thornberc9d28d52013-10-31 13:55:48 -040094}
95
96/*----------------------------------------------------------------*/
97
Joe Thornberc6b4fcb2013-03-01 22:45:51 +000098#define PRISON_CELLS 1024
99#define MIGRATION_POOL_SIZE 128
100#define COMMIT_PERIOD HZ
101#define MIGRATION_COUNT_WINDOW 10
102
103/*
Mike Snitzer05473042013-08-16 10:54:19 -0400104 * The block size of the device holding cache data must be
105 * between 32KB and 1GB.
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000106 */
107#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT)
Mike Snitzer05473042013-08-16 10:54:19 -0400108#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000109
110/*
111 * FIXME: the cache is read/write for the time being.
112 */
Joe Thornber2ee57d52013-10-24 14:10:29 -0400113enum cache_metadata_mode {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000114 CM_WRITE, /* metadata may be changed */
115 CM_READ_ONLY, /* metadata may not be changed */
116};
117
Joe Thornber2ee57d52013-10-24 14:10:29 -0400118enum 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
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000141struct cache_features {
Joe Thornber2ee57d52013-10-24 14:10:29 -0400142 enum cache_metadata_mode mode;
143 enum cache_io_mode io_mode;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000144};
145
146struct 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
Joe Thornber65790ff2013-11-08 16:39:50 +0000159/*
160 * Defines a range of cblocks, begin to (end - 1) are in the range. end is
161 * the one-past-the-end value.
162 */
163struct cblock_range {
164 dm_cblock_t begin;
165 dm_cblock_t end;
166};
167
168struct 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
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000178struct cache {
179 struct dm_target *ti;
180 struct dm_target_callbacks callbacks;
181
Mike Snitzerc9ec5d72013-08-16 10:54:21 -0400182 struct dm_cache_metadata *cmd;
183
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000184 /*
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
199 /*
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000200 * 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
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000216 spinlock_t lock;
217 struct bio_list deferred_bios;
218 struct bio_list deferred_flush_bios;
Joe Thornbere2e74d62013-03-20 17:21:27 +0000219 struct bio_list deferred_writethrough_bios;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000220 struct list_head quiesced_migrations;
221 struct list_head completed_migrations;
222 struct list_head need_commit_migrations;
223 sector_t migration_threshold;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000224 wait_queue_head_t migration_wait;
Mike Snitzerc9ec5d72013-08-16 10:54:21 -0400225 atomic_t nr_migrations;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000226
Joe Thornber66cb1912013-10-30 17:11:58 +0000227 wait_queue_head_t quiescing_wait;
Joe Thornber238f8362013-10-30 17:29:30 +0000228 atomic_t quiescing;
Joe Thornber66cb1912013-10-30 17:11:58 +0000229 atomic_t quiescing_ack;
230
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000231 /*
232 * cache_size entries, dirty if set
233 */
Anssi Hannula44fa8162014-08-01 11:55:47 -0400234 atomic_t nr_dirty;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000235 unsigned long *dirty_bitset;
236
237 /*
238 * origin_blocks entries, discarded if set.
239 */
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400240 dm_oblock_t discard_nr_blocks;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000241 unsigned long *discard_bitset;
Mike Snitzerc9ec5d72013-08-16 10:54:21 -0400242
243 /*
244 * Rather than reconstructing the table line for the status we just
245 * save it and regurgitate.
246 */
247 unsigned nr_ctr_args;
248 const char **ctr_args;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000249
250 struct dm_kcopyd_client *copier;
251 struct workqueue_struct *wq;
252 struct work_struct worker;
253
254 struct delayed_work waker;
255 unsigned long last_commit_jiffies;
256
257 struct dm_bio_prison *prison;
258 struct dm_deferred_set *all_io_ds;
259
260 mempool_t *migration_pool;
261 struct dm_cache_migration *next_migration;
262
263 struct dm_cache_policy *policy;
264 unsigned policy_nr_args;
265
266 bool need_tick_bio:1;
267 bool sized:1;
Joe Thornber65790ff2013-11-08 16:39:50 +0000268 bool invalidate:1;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000269 bool commit_requested:1;
270 bool loaded_mappings:1;
271 bool loaded_discards:1;
272
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000273 /*
Mike Snitzerc9ec5d72013-08-16 10:54:21 -0400274 * Cache features such as write-through.
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000275 */
Mike Snitzerc9ec5d72013-08-16 10:54:21 -0400276 struct cache_features features;
277
278 struct cache_stats stats;
Joe Thornber65790ff2013-11-08 16:39:50 +0000279
280 /*
281 * Invalidation fields.
282 */
283 spinlock_t invalidation_lock;
284 struct list_head invalidation_requests;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000285};
286
287struct per_bio_data {
288 bool tick:1;
289 unsigned req_nr:2;
290 struct dm_deferred_entry *all_io_entry;
Mike Snitzerc6eda5e2014-01-31 14:11:54 -0500291 struct dm_hook_info hook_info;
Joe Thornbere2e74d62013-03-20 17:21:27 +0000292
Mike Snitzer19b00922013-04-05 15:36:34 +0100293 /*
294 * writethrough fields. These MUST remain at the end of this
295 * structure and the 'cache' member must be the first as it
Joe Thornberaeed1422013-05-10 14:37:18 +0100296 * is used to determine the offset of the writethrough fields.
Mike Snitzer19b00922013-04-05 15:36:34 +0100297 */
Joe Thornbere2e74d62013-03-20 17:21:27 +0000298 struct cache *cache;
299 dm_cblock_t cblock;
Darrick J. Wongb844fe62013-04-05 15:36:32 +0100300 struct dm_bio_details bio_details;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000301};
302
303struct dm_cache_migration {
304 struct list_head list;
305 struct cache *cache;
306
307 unsigned long start_jiffies;
308 dm_oblock_t old_oblock;
309 dm_oblock_t new_oblock;
310 dm_cblock_t cblock;
311
312 bool err:1;
313 bool writeback:1;
314 bool demote:1;
315 bool promote:1;
Joe Thornberc9d28d52013-10-31 13:55:48 -0400316 bool requeue_holder:1;
Joe Thornber65790ff2013-11-08 16:39:50 +0000317 bool invalidate:1;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000318
319 struct dm_bio_prison_cell *old_ocell;
320 struct dm_bio_prison_cell *new_ocell;
321};
322
323/*
324 * Processing a bio in the worker thread may require these memory
325 * allocations. We prealloc to avoid deadlocks (the same worker thread
326 * frees them back to the mempool).
327 */
328struct prealloc {
329 struct dm_cache_migration *mg;
330 struct dm_bio_prison_cell *cell1;
331 struct dm_bio_prison_cell *cell2;
332};
333
334static void wake_worker(struct cache *cache)
335{
336 queue_work(cache->wq, &cache->worker);
337}
338
339/*----------------------------------------------------------------*/
340
341static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache)
342{
343 /* FIXME: change to use a local slab. */
344 return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT);
345}
346
347static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell)
348{
349 dm_bio_prison_free_cell(cache->prison, cell);
350}
351
352static int prealloc_data_structs(struct cache *cache, struct prealloc *p)
353{
354 if (!p->mg) {
355 p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);
356 if (!p->mg)
357 return -ENOMEM;
358 }
359
360 if (!p->cell1) {
361 p->cell1 = alloc_prison_cell(cache);
362 if (!p->cell1)
363 return -ENOMEM;
364 }
365
366 if (!p->cell2) {
367 p->cell2 = alloc_prison_cell(cache);
368 if (!p->cell2)
369 return -ENOMEM;
370 }
371
372 return 0;
373}
374
375static void prealloc_free_structs(struct cache *cache, struct prealloc *p)
376{
377 if (p->cell2)
378 free_prison_cell(cache, p->cell2);
379
380 if (p->cell1)
381 free_prison_cell(cache, p->cell1);
382
383 if (p->mg)
384 mempool_free(p->mg, cache->migration_pool);
385}
386
387static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p)
388{
389 struct dm_cache_migration *mg = p->mg;
390
391 BUG_ON(!mg);
392 p->mg = NULL;
393
394 return mg;
395}
396
397/*
398 * You must have a cell within the prealloc struct to return. If not this
399 * function will BUG() rather than returning NULL.
400 */
401static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p)
402{
403 struct dm_bio_prison_cell *r = NULL;
404
405 if (p->cell1) {
406 r = p->cell1;
407 p->cell1 = NULL;
408
409 } else if (p->cell2) {
410 r = p->cell2;
411 p->cell2 = NULL;
412 } else
413 BUG();
414
415 return r;
416}
417
418/*
419 * You can't have more than two cells in a prealloc struct. BUG() will be
420 * called if you try and overfill.
421 */
422static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell)
423{
424 if (!p->cell2)
425 p->cell2 = cell;
426
427 else if (!p->cell1)
428 p->cell1 = cell;
429
430 else
431 BUG();
432}
433
434/*----------------------------------------------------------------*/
435
436static void build_key(dm_oblock_t oblock, struct dm_cell_key *key)
437{
438 key->virtual = 0;
439 key->dev = 0;
440 key->block = from_oblock(oblock);
441}
442
443/*
444 * The caller hands in a preallocated cell, and a free function for it.
445 * The cell will be freed if there's an error, or if it wasn't used because
446 * a cell with that key already exists.
447 */
448typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell);
449
450static int bio_detain(struct cache *cache, dm_oblock_t oblock,
451 struct bio *bio, struct dm_bio_prison_cell *cell_prealloc,
452 cell_free_fn free_fn, void *free_context,
453 struct dm_bio_prison_cell **cell_result)
454{
455 int r;
456 struct dm_cell_key key;
457
458 build_key(oblock, &key);
459 r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result);
460 if (r)
461 free_fn(free_context, cell_prealloc);
462
463 return r;
464}
465
466static int get_cell(struct cache *cache,
467 dm_oblock_t oblock,
468 struct prealloc *structs,
469 struct dm_bio_prison_cell **cell_result)
470{
471 int r;
472 struct dm_cell_key key;
473 struct dm_bio_prison_cell *cell_prealloc;
474
475 cell_prealloc = prealloc_get_cell(structs);
476
477 build_key(oblock, &key);
478 r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result);
479 if (r)
480 prealloc_put_cell(structs, cell_prealloc);
481
482 return r;
483}
484
Joe Thornberaeed1422013-05-10 14:37:18 +0100485/*----------------------------------------------------------------*/
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000486
487static bool is_dirty(struct cache *cache, dm_cblock_t b)
488{
489 return test_bit(from_cblock(b), cache->dirty_bitset);
490}
491
492static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
493{
494 if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) {
Anssi Hannula44fa8162014-08-01 11:55:47 -0400495 atomic_inc(&cache->nr_dirty);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000496 policy_set_dirty(cache->policy, oblock);
497 }
498}
499
500static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
501{
502 if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) {
503 policy_clear_dirty(cache->policy, oblock);
Anssi Hannula44fa8162014-08-01 11:55:47 -0400504 if (atomic_dec_return(&cache->nr_dirty) == 0)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000505 dm_table_event(cache->ti->table);
506 }
507}
508
509/*----------------------------------------------------------------*/
Joe Thornberaeed1422013-05-10 14:37:18 +0100510
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000511static bool block_size_is_power_of_two(struct cache *cache)
512{
513 return cache->sectors_per_block_shift >= 0;
514}
515
Mikulas Patocka43aeaa22013-07-10 23:41:17 +0100516/* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */
517#if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6
518__always_inline
519#endif
Joe Thornber414dd672013-03-20 17:21:25 +0000520static dm_block_t block_div(dm_block_t b, uint32_t n)
521{
522 do_div(b, n);
523
524 return b;
525}
526
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400527static void set_discard(struct cache *cache, dm_oblock_t b)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000528{
529 unsigned long flags;
530
531 atomic_inc(&cache->stats.discard_count);
532
533 spin_lock_irqsave(&cache->lock, flags);
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400534 set_bit(from_oblock(b), cache->discard_bitset);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000535 spin_unlock_irqrestore(&cache->lock, flags);
536}
537
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400538static void clear_discard(struct cache *cache, dm_oblock_t b)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000539{
540 unsigned long flags;
541
542 spin_lock_irqsave(&cache->lock, flags);
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400543 clear_bit(from_oblock(b), cache->discard_bitset);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000544 spin_unlock_irqrestore(&cache->lock, flags);
545}
546
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400547static bool is_discarded(struct cache *cache, dm_oblock_t b)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000548{
549 int r;
550 unsigned long flags;
551
552 spin_lock_irqsave(&cache->lock, flags);
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400553 r = test_bit(from_oblock(b), cache->discard_bitset);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000554 spin_unlock_irqrestore(&cache->lock, flags);
555
556 return r;
557}
558
559static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b)
560{
561 int r;
562 unsigned long flags;
563
564 spin_lock_irqsave(&cache->lock, flags);
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400565 r = test_bit(from_oblock(b), cache->discard_bitset);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000566 spin_unlock_irqrestore(&cache->lock, flags);
567
568 return r;
569}
570
571/*----------------------------------------------------------------*/
572
573static void load_stats(struct cache *cache)
574{
575 struct dm_cache_statistics stats;
576
577 dm_cache_metadata_get_stats(cache->cmd, &stats);
578 atomic_set(&cache->stats.read_hit, stats.read_hits);
579 atomic_set(&cache->stats.read_miss, stats.read_misses);
580 atomic_set(&cache->stats.write_hit, stats.write_hits);
581 atomic_set(&cache->stats.write_miss, stats.write_misses);
582}
583
584static void save_stats(struct cache *cache)
585{
586 struct dm_cache_statistics stats;
587
588 stats.read_hits = atomic_read(&cache->stats.read_hit);
589 stats.read_misses = atomic_read(&cache->stats.read_miss);
590 stats.write_hits = atomic_read(&cache->stats.write_hit);
591 stats.write_misses = atomic_read(&cache->stats.write_miss);
592
593 dm_cache_metadata_set_stats(cache->cmd, &stats);
594}
595
596/*----------------------------------------------------------------
597 * Per bio data
598 *--------------------------------------------------------------*/
Mike Snitzer19b00922013-04-05 15:36:34 +0100599
600/*
601 * If using writeback, leave out struct per_bio_data's writethrough fields.
602 */
603#define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache))
604#define PB_DATA_SIZE_WT (sizeof(struct per_bio_data))
605
Joe Thornber2ee57d52013-10-24 14:10:29 -0400606static bool writethrough_mode(struct cache_features *f)
607{
608 return f->io_mode == CM_IO_WRITETHROUGH;
609}
610
611static bool writeback_mode(struct cache_features *f)
612{
613 return f->io_mode == CM_IO_WRITEBACK;
614}
615
616static bool passthrough_mode(struct cache_features *f)
617{
618 return f->io_mode == CM_IO_PASSTHROUGH;
619}
620
Mike Snitzer19b00922013-04-05 15:36:34 +0100621static size_t get_per_bio_data_size(struct cache *cache)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000622{
Joe Thornber2ee57d52013-10-24 14:10:29 -0400623 return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB;
Mike Snitzer19b00922013-04-05 15:36:34 +0100624}
625
626static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size)
627{
628 struct per_bio_data *pb = dm_per_bio_data(bio, data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000629 BUG_ON(!pb);
630 return pb;
631}
632
Mike Snitzer19b00922013-04-05 15:36:34 +0100633static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000634{
Mike Snitzer19b00922013-04-05 15:36:34 +0100635 struct per_bio_data *pb = get_per_bio_data(bio, data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000636
637 pb->tick = false;
638 pb->req_nr = dm_bio_get_target_bio_nr(bio);
639 pb->all_io_entry = NULL;
640
641 return pb;
642}
643
644/*----------------------------------------------------------------
645 * Remapping
646 *--------------------------------------------------------------*/
647static void remap_to_origin(struct cache *cache, struct bio *bio)
648{
649 bio->bi_bdev = cache->origin_dev->bdev;
650}
651
652static void remap_to_cache(struct cache *cache, struct bio *bio,
653 dm_cblock_t cblock)
654{
Kent Overstreet4f024f32013-10-11 15:44:27 -0700655 sector_t bi_sector = bio->bi_iter.bi_sector;
Heinz Mauelshagene0d849f2014-02-27 22:46:48 +0100656 sector_t block = from_cblock(cblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000657
658 bio->bi_bdev = cache->cache_dev->bdev;
659 if (!block_size_is_power_of_two(cache))
Kent Overstreet4f024f32013-10-11 15:44:27 -0700660 bio->bi_iter.bi_sector =
Heinz Mauelshagene0d849f2014-02-27 22:46:48 +0100661 (block * cache->sectors_per_block) +
Kent Overstreet4f024f32013-10-11 15:44:27 -0700662 sector_div(bi_sector, cache->sectors_per_block);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000663 else
Kent Overstreet4f024f32013-10-11 15:44:27 -0700664 bio->bi_iter.bi_sector =
Heinz Mauelshagene0d849f2014-02-27 22:46:48 +0100665 (block << cache->sectors_per_block_shift) |
Kent Overstreet4f024f32013-10-11 15:44:27 -0700666 (bi_sector & (cache->sectors_per_block - 1));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000667}
668
669static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)
670{
671 unsigned long flags;
Mike Snitzer19b00922013-04-05 15:36:34 +0100672 size_t pb_data_size = get_per_bio_data_size(cache);
673 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000674
675 spin_lock_irqsave(&cache->lock, flags);
676 if (cache->need_tick_bio &&
677 !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) {
678 pb->tick = true;
679 cache->need_tick_bio = false;
680 }
681 spin_unlock_irqrestore(&cache->lock, flags);
682}
683
684static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio,
685 dm_oblock_t oblock)
686{
687 check_if_tick_bio_needed(cache, bio);
688 remap_to_origin(cache, bio);
689 if (bio_data_dir(bio) == WRITE)
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400690 clear_discard(cache, oblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000691}
692
693static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
694 dm_oblock_t oblock, dm_cblock_t cblock)
695{
Joe Thornberf8e5f012013-10-21 12:51:45 +0100696 check_if_tick_bio_needed(cache, bio);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000697 remap_to_cache(cache, bio, cblock);
698 if (bio_data_dir(bio) == WRITE) {
699 set_dirty(cache, oblock, cblock);
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400700 clear_discard(cache, oblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000701 }
702}
703
704static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio)
705{
Kent Overstreet4f024f32013-10-11 15:44:27 -0700706 sector_t block_nr = bio->bi_iter.bi_sector;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000707
708 if (!block_size_is_power_of_two(cache))
709 (void) sector_div(block_nr, cache->sectors_per_block);
710 else
711 block_nr >>= cache->sectors_per_block_shift;
712
713 return to_oblock(block_nr);
714}
715
716static int bio_triggers_commit(struct cache *cache, struct bio *bio)
717{
718 return bio->bi_rw & (REQ_FLUSH | REQ_FUA);
719}
720
Joe Thornber8c081b52014-05-13 16:18:38 +0100721/*
722 * You must increment the deferred set whilst the prison cell is held. To
723 * encourage this, we ask for 'cell' to be passed in.
724 */
725static void inc_ds(struct cache *cache, struct bio *bio,
726 struct dm_bio_prison_cell *cell)
727{
728 size_t pb_data_size = get_per_bio_data_size(cache);
729 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
730
731 BUG_ON(!cell);
732 BUG_ON(pb->all_io_entry);
733
734 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
735}
736
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000737static void issue(struct cache *cache, struct bio *bio)
738{
739 unsigned long flags;
740
741 if (!bio_triggers_commit(cache, bio)) {
742 generic_make_request(bio);
743 return;
744 }
745
746 /*
747 * Batch together any bios that trigger commits and then issue a
748 * single commit for them in do_worker().
749 */
750 spin_lock_irqsave(&cache->lock, flags);
751 cache->commit_requested = true;
752 bio_list_add(&cache->deferred_flush_bios, bio);
753 spin_unlock_irqrestore(&cache->lock, flags);
754}
755
Joe Thornber8c081b52014-05-13 16:18:38 +0100756static void inc_and_issue(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell *cell)
757{
758 inc_ds(cache, bio, cell);
759 issue(cache, bio);
760}
761
Joe Thornbere2e74d62013-03-20 17:21:27 +0000762static void defer_writethrough_bio(struct cache *cache, struct bio *bio)
763{
764 unsigned long flags;
765
766 spin_lock_irqsave(&cache->lock, flags);
767 bio_list_add(&cache->deferred_writethrough_bios, bio);
768 spin_unlock_irqrestore(&cache->lock, flags);
769
770 wake_worker(cache);
771}
772
773static void writethrough_endio(struct bio *bio, int err)
774{
Mike Snitzer19b00922013-04-05 15:36:34 +0100775 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
Joe Thornberc9d28d52013-10-31 13:55:48 -0400776
777 dm_unhook_bio(&pb->hook_info, bio);
Joe Thornbere2e74d62013-03-20 17:21:27 +0000778
779 if (err) {
780 bio_endio(bio, err);
781 return;
782 }
783
Darrick J. Wongb844fe62013-04-05 15:36:32 +0100784 dm_bio_restore(&pb->bio_details, bio);
Joe Thornbere2e74d62013-03-20 17:21:27 +0000785 remap_to_cache(pb->cache, bio, pb->cblock);
786
787 /*
788 * We can't issue this bio directly, since we're in interrupt
Joe Thornberaeed1422013-05-10 14:37:18 +0100789 * context. So it gets put on a bio list for processing by the
Joe Thornbere2e74d62013-03-20 17:21:27 +0000790 * worker thread.
791 */
792 defer_writethrough_bio(pb->cache, bio);
793}
794
795/*
796 * When running in writethrough mode we need to send writes to clean blocks
797 * to both the cache and origin devices. In future we'd like to clone the
798 * bio and send them in parallel, but for now we're doing them in
799 * series as this is easier.
800 */
801static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio,
802 dm_oblock_t oblock, dm_cblock_t cblock)
803{
Mike Snitzer19b00922013-04-05 15:36:34 +0100804 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
Joe Thornbere2e74d62013-03-20 17:21:27 +0000805
806 pb->cache = cache;
807 pb->cblock = cblock;
Joe Thornberc9d28d52013-10-31 13:55:48 -0400808 dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL);
Darrick J. Wongb844fe62013-04-05 15:36:32 +0100809 dm_bio_record(&pb->bio_details, bio);
Joe Thornbere2e74d62013-03-20 17:21:27 +0000810
811 remap_to_origin_clear_discard(pb->cache, bio, oblock);
812}
813
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000814/*----------------------------------------------------------------
815 * Migration processing
816 *
817 * Migration covers moving data from the origin device to the cache, or
818 * vice versa.
819 *--------------------------------------------------------------*/
820static void free_migration(struct dm_cache_migration *mg)
821{
822 mempool_free(mg, mg->cache->migration_pool);
823}
824
825static void inc_nr_migrations(struct cache *cache)
826{
827 atomic_inc(&cache->nr_migrations);
828}
829
830static void dec_nr_migrations(struct cache *cache)
831{
832 atomic_dec(&cache->nr_migrations);
833
834 /*
835 * Wake the worker in case we're suspending the target.
836 */
837 wake_up(&cache->migration_wait);
838}
839
840static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
841 bool holder)
842{
843 (holder ? dm_cell_release : dm_cell_release_no_holder)
844 (cache->prison, cell, &cache->deferred_bios);
845 free_prison_cell(cache, cell);
846}
847
848static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
849 bool holder)
850{
851 unsigned long flags;
852
853 spin_lock_irqsave(&cache->lock, flags);
854 __cell_defer(cache, cell, holder);
855 spin_unlock_irqrestore(&cache->lock, flags);
856
857 wake_worker(cache);
858}
859
860static void cleanup_migration(struct dm_cache_migration *mg)
861{
Joe Thornber66cb1912013-10-30 17:11:58 +0000862 struct cache *cache = mg->cache;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000863 free_migration(mg);
Joe Thornber66cb1912013-10-30 17:11:58 +0000864 dec_nr_migrations(cache);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000865}
866
867static void migration_failure(struct dm_cache_migration *mg)
868{
869 struct cache *cache = mg->cache;
870
871 if (mg->writeback) {
872 DMWARN_LIMIT("writeback failed; couldn't copy block");
873 set_dirty(cache, mg->old_oblock, mg->cblock);
874 cell_defer(cache, mg->old_ocell, false);
875
876 } else if (mg->demote) {
877 DMWARN_LIMIT("demotion failed; couldn't copy block");
878 policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock);
879
Heinz Mauelshagen80f659f2013-10-14 17:10:47 +0200880 cell_defer(cache, mg->old_ocell, mg->promote ? false : true);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000881 if (mg->promote)
Heinz Mauelshagen80f659f2013-10-14 17:10:47 +0200882 cell_defer(cache, mg->new_ocell, true);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000883 } else {
884 DMWARN_LIMIT("promotion failed; couldn't copy block");
885 policy_remove_mapping(cache->policy, mg->new_oblock);
Heinz Mauelshagen80f659f2013-10-14 17:10:47 +0200886 cell_defer(cache, mg->new_ocell, true);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000887 }
888
889 cleanup_migration(mg);
890}
891
892static void migration_success_pre_commit(struct dm_cache_migration *mg)
893{
894 unsigned long flags;
895 struct cache *cache = mg->cache;
896
897 if (mg->writeback) {
898 cell_defer(cache, mg->old_ocell, false);
899 clear_dirty(cache, mg->old_oblock, mg->cblock);
900 cleanup_migration(mg);
901 return;
902
903 } else if (mg->demote) {
904 if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) {
905 DMWARN_LIMIT("demotion failed; couldn't update on disk metadata");
906 policy_force_mapping(cache->policy, mg->new_oblock,
907 mg->old_oblock);
908 if (mg->promote)
909 cell_defer(cache, mg->new_ocell, true);
910 cleanup_migration(mg);
911 return;
912 }
913 } else {
914 if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) {
915 DMWARN_LIMIT("promotion failed; couldn't update on disk metadata");
916 policy_remove_mapping(cache->policy, mg->new_oblock);
917 cleanup_migration(mg);
918 return;
919 }
920 }
921
922 spin_lock_irqsave(&cache->lock, flags);
923 list_add_tail(&mg->list, &cache->need_commit_migrations);
924 cache->commit_requested = true;
925 spin_unlock_irqrestore(&cache->lock, flags);
926}
927
928static void migration_success_post_commit(struct dm_cache_migration *mg)
929{
930 unsigned long flags;
931 struct cache *cache = mg->cache;
932
933 if (mg->writeback) {
934 DMWARN("writeback unexpectedly triggered commit");
935 return;
936
937 } else if (mg->demote) {
Heinz Mauelshagen80f659f2013-10-14 17:10:47 +0200938 cell_defer(cache, mg->old_ocell, mg->promote ? false : true);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000939
940 if (mg->promote) {
941 mg->demote = false;
942
943 spin_lock_irqsave(&cache->lock, flags);
944 list_add_tail(&mg->list, &cache->quiesced_migrations);
945 spin_unlock_irqrestore(&cache->lock, flags);
946
Joe Thornber65790ff2013-11-08 16:39:50 +0000947 } else {
948 if (mg->invalidate)
949 policy_remove_mapping(cache->policy, mg->old_oblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000950 cleanup_migration(mg);
Joe Thornber65790ff2013-11-08 16:39:50 +0000951 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000952
953 } else {
Joe Thornberc9d28d52013-10-31 13:55:48 -0400954 if (mg->requeue_holder)
955 cell_defer(cache, mg->new_ocell, true);
956 else {
957 bio_endio(mg->new_ocell->holder, 0);
958 cell_defer(cache, mg->new_ocell, false);
959 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000960 clear_dirty(cache, mg->new_oblock, mg->cblock);
961 cleanup_migration(mg);
962 }
963}
964
965static void copy_complete(int read_err, unsigned long write_err, void *context)
966{
967 unsigned long flags;
968 struct dm_cache_migration *mg = (struct dm_cache_migration *) context;
969 struct cache *cache = mg->cache;
970
971 if (read_err || write_err)
972 mg->err = true;
973
974 spin_lock_irqsave(&cache->lock, flags);
975 list_add_tail(&mg->list, &cache->completed_migrations);
976 spin_unlock_irqrestore(&cache->lock, flags);
977
978 wake_worker(cache);
979}
980
981static void issue_copy_real(struct dm_cache_migration *mg)
982{
983 int r;
984 struct dm_io_region o_region, c_region;
985 struct cache *cache = mg->cache;
Heinz Mauelshagen8b9d9662014-03-12 00:40:05 +0100986 sector_t cblock = from_cblock(mg->cblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000987
988 o_region.bdev = cache->origin_dev->bdev;
989 o_region.count = cache->sectors_per_block;
990
991 c_region.bdev = cache->cache_dev->bdev;
Heinz Mauelshagen8b9d9662014-03-12 00:40:05 +0100992 c_region.sector = cblock * cache->sectors_per_block;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000993 c_region.count = cache->sectors_per_block;
994
995 if (mg->writeback || mg->demote) {
996 /* demote */
997 o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block;
998 r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg);
999 } else {
1000 /* promote */
1001 o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block;
1002 r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg);
1003 }
1004
Heinz Mauelshagen2c2263c2013-10-14 17:14:45 +02001005 if (r < 0) {
1006 DMERR_LIMIT("issuing migration failed");
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001007 migration_failure(mg);
Heinz Mauelshagen2c2263c2013-10-14 17:14:45 +02001008 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001009}
1010
Joe Thornberc9d28d52013-10-31 13:55:48 -04001011static void overwrite_endio(struct bio *bio, int err)
1012{
1013 struct dm_cache_migration *mg = bio->bi_private;
1014 struct cache *cache = mg->cache;
1015 size_t pb_data_size = get_per_bio_data_size(cache);
1016 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1017 unsigned long flags;
1018
Mike Snitzer80ae49a2014-01-31 14:30:37 -05001019 dm_unhook_bio(&pb->hook_info, bio);
1020
Joe Thornberc9d28d52013-10-31 13:55:48 -04001021 if (err)
1022 mg->err = true;
1023
Mike Snitzer80ae49a2014-01-31 14:30:37 -05001024 mg->requeue_holder = false;
1025
Joe Thornberc9d28d52013-10-31 13:55:48 -04001026 spin_lock_irqsave(&cache->lock, flags);
1027 list_add_tail(&mg->list, &cache->completed_migrations);
Joe Thornberc9d28d52013-10-31 13:55:48 -04001028 spin_unlock_irqrestore(&cache->lock, flags);
1029
1030 wake_worker(cache);
1031}
1032
1033static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio)
1034{
1035 size_t pb_data_size = get_per_bio_data_size(mg->cache);
1036 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1037
1038 dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg);
1039 remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock);
Joe Thornber8c081b52014-05-13 16:18:38 +01001040
1041 /*
1042 * No need to inc_ds() here, since the cell will be held for the
1043 * duration of the io.
1044 */
Joe Thornberc9d28d52013-10-31 13:55:48 -04001045 generic_make_request(bio);
1046}
1047
1048static bool bio_writes_complete_block(struct cache *cache, struct bio *bio)
1049{
1050 return (bio_data_dir(bio) == WRITE) &&
Kent Overstreet4f024f32013-10-11 15:44:27 -07001051 (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT));
Joe Thornberc9d28d52013-10-31 13:55:48 -04001052}
1053
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001054static void avoid_copy(struct dm_cache_migration *mg)
1055{
1056 atomic_inc(&mg->cache->stats.copies_avoided);
1057 migration_success_pre_commit(mg);
1058}
1059
1060static void issue_copy(struct dm_cache_migration *mg)
1061{
1062 bool avoid;
1063 struct cache *cache = mg->cache;
1064
1065 if (mg->writeback || mg->demote)
1066 avoid = !is_dirty(cache, mg->cblock) ||
1067 is_discarded_oblock(cache, mg->old_oblock);
Joe Thornberc9d28d52013-10-31 13:55:48 -04001068 else {
1069 struct bio *bio = mg->new_ocell->holder;
1070
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001071 avoid = is_discarded_oblock(cache, mg->new_oblock);
1072
Joe Thornberc9d28d52013-10-31 13:55:48 -04001073 if (!avoid && bio_writes_complete_block(cache, bio)) {
1074 issue_overwrite(mg, bio);
1075 return;
1076 }
1077 }
1078
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001079 avoid ? avoid_copy(mg) : issue_copy_real(mg);
1080}
1081
1082static void complete_migration(struct dm_cache_migration *mg)
1083{
1084 if (mg->err)
1085 migration_failure(mg);
1086 else
1087 migration_success_pre_commit(mg);
1088}
1089
1090static void process_migrations(struct cache *cache, struct list_head *head,
1091 void (*fn)(struct dm_cache_migration *))
1092{
1093 unsigned long flags;
1094 struct list_head list;
1095 struct dm_cache_migration *mg, *tmp;
1096
1097 INIT_LIST_HEAD(&list);
1098 spin_lock_irqsave(&cache->lock, flags);
1099 list_splice_init(head, &list);
1100 spin_unlock_irqrestore(&cache->lock, flags);
1101
1102 list_for_each_entry_safe(mg, tmp, &list, list)
1103 fn(mg);
1104}
1105
1106static void __queue_quiesced_migration(struct dm_cache_migration *mg)
1107{
1108 list_add_tail(&mg->list, &mg->cache->quiesced_migrations);
1109}
1110
1111static void queue_quiesced_migration(struct dm_cache_migration *mg)
1112{
1113 unsigned long flags;
1114 struct cache *cache = mg->cache;
1115
1116 spin_lock_irqsave(&cache->lock, flags);
1117 __queue_quiesced_migration(mg);
1118 spin_unlock_irqrestore(&cache->lock, flags);
1119
1120 wake_worker(cache);
1121}
1122
1123static void queue_quiesced_migrations(struct cache *cache, struct list_head *work)
1124{
1125 unsigned long flags;
1126 struct dm_cache_migration *mg, *tmp;
1127
1128 spin_lock_irqsave(&cache->lock, flags);
1129 list_for_each_entry_safe(mg, tmp, work, list)
1130 __queue_quiesced_migration(mg);
1131 spin_unlock_irqrestore(&cache->lock, flags);
1132
1133 wake_worker(cache);
1134}
1135
1136static void check_for_quiesced_migrations(struct cache *cache,
1137 struct per_bio_data *pb)
1138{
1139 struct list_head work;
1140
1141 if (!pb->all_io_entry)
1142 return;
1143
1144 INIT_LIST_HEAD(&work);
Joe Thornber8c081b52014-05-13 16:18:38 +01001145 dm_deferred_entry_dec(pb->all_io_entry, &work);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001146
1147 if (!list_empty(&work))
1148 queue_quiesced_migrations(cache, &work);
1149}
1150
1151static void quiesce_migration(struct dm_cache_migration *mg)
1152{
1153 if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list))
1154 queue_quiesced_migration(mg);
1155}
1156
1157static void promote(struct cache *cache, struct prealloc *structs,
1158 dm_oblock_t oblock, dm_cblock_t cblock,
1159 struct dm_bio_prison_cell *cell)
1160{
1161 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1162
1163 mg->err = false;
1164 mg->writeback = false;
1165 mg->demote = false;
1166 mg->promote = true;
Joe Thornberc9d28d52013-10-31 13:55:48 -04001167 mg->requeue_holder = true;
Joe Thornber65790ff2013-11-08 16:39:50 +00001168 mg->invalidate = false;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001169 mg->cache = cache;
1170 mg->new_oblock = oblock;
1171 mg->cblock = cblock;
1172 mg->old_ocell = NULL;
1173 mg->new_ocell = cell;
1174 mg->start_jiffies = jiffies;
1175
1176 inc_nr_migrations(cache);
1177 quiesce_migration(mg);
1178}
1179
1180static void writeback(struct cache *cache, struct prealloc *structs,
1181 dm_oblock_t oblock, dm_cblock_t cblock,
1182 struct dm_bio_prison_cell *cell)
1183{
1184 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1185
1186 mg->err = false;
1187 mg->writeback = true;
1188 mg->demote = false;
1189 mg->promote = false;
Joe Thornberc9d28d52013-10-31 13:55:48 -04001190 mg->requeue_holder = true;
Joe Thornber65790ff2013-11-08 16:39:50 +00001191 mg->invalidate = false;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001192 mg->cache = cache;
1193 mg->old_oblock = oblock;
1194 mg->cblock = cblock;
1195 mg->old_ocell = cell;
1196 mg->new_ocell = NULL;
1197 mg->start_jiffies = jiffies;
1198
1199 inc_nr_migrations(cache);
1200 quiesce_migration(mg);
1201}
1202
1203static void demote_then_promote(struct cache *cache, struct prealloc *structs,
1204 dm_oblock_t old_oblock, dm_oblock_t new_oblock,
1205 dm_cblock_t cblock,
1206 struct dm_bio_prison_cell *old_ocell,
1207 struct dm_bio_prison_cell *new_ocell)
1208{
1209 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1210
1211 mg->err = false;
1212 mg->writeback = false;
1213 mg->demote = true;
1214 mg->promote = true;
Joe Thornberc9d28d52013-10-31 13:55:48 -04001215 mg->requeue_holder = true;
Joe Thornber65790ff2013-11-08 16:39:50 +00001216 mg->invalidate = false;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001217 mg->cache = cache;
1218 mg->old_oblock = old_oblock;
1219 mg->new_oblock = new_oblock;
1220 mg->cblock = cblock;
1221 mg->old_ocell = old_ocell;
1222 mg->new_ocell = new_ocell;
1223 mg->start_jiffies = jiffies;
1224
1225 inc_nr_migrations(cache);
1226 quiesce_migration(mg);
1227}
1228
Joe Thornber2ee57d52013-10-24 14:10:29 -04001229/*
1230 * Invalidate a cache entry. No writeback occurs; any changes in the cache
1231 * block are thrown away.
1232 */
1233static void invalidate(struct cache *cache, struct prealloc *structs,
1234 dm_oblock_t oblock, dm_cblock_t cblock,
1235 struct dm_bio_prison_cell *cell)
1236{
1237 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1238
1239 mg->err = false;
1240 mg->writeback = false;
1241 mg->demote = true;
1242 mg->promote = false;
1243 mg->requeue_holder = true;
Joe Thornber65790ff2013-11-08 16:39:50 +00001244 mg->invalidate = true;
Joe Thornber2ee57d52013-10-24 14:10:29 -04001245 mg->cache = cache;
1246 mg->old_oblock = oblock;
1247 mg->cblock = cblock;
1248 mg->old_ocell = cell;
1249 mg->new_ocell = NULL;
1250 mg->start_jiffies = jiffies;
1251
1252 inc_nr_migrations(cache);
1253 quiesce_migration(mg);
1254}
1255
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001256/*----------------------------------------------------------------
1257 * bio processing
1258 *--------------------------------------------------------------*/
1259static void defer_bio(struct cache *cache, struct bio *bio)
1260{
1261 unsigned long flags;
1262
1263 spin_lock_irqsave(&cache->lock, flags);
1264 bio_list_add(&cache->deferred_bios, bio);
1265 spin_unlock_irqrestore(&cache->lock, flags);
1266
1267 wake_worker(cache);
1268}
1269
1270static void process_flush_bio(struct cache *cache, struct bio *bio)
1271{
Mike Snitzer19b00922013-04-05 15:36:34 +01001272 size_t pb_data_size = get_per_bio_data_size(cache);
1273 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001274
Kent Overstreet4f024f32013-10-11 15:44:27 -07001275 BUG_ON(bio->bi_iter.bi_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001276 if (!pb->req_nr)
1277 remap_to_origin(cache, bio);
1278 else
1279 remap_to_cache(cache, bio, 0);
1280
Joe Thornber8c081b52014-05-13 16:18:38 +01001281 /*
1282 * REQ_FLUSH is not directed at any particular block so we don't
1283 * need to inc_ds(). REQ_FUA's are split into a write + REQ_FLUSH
1284 * by dm-core.
1285 */
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001286 issue(cache, bio);
1287}
1288
1289/*
1290 * People generally discard large parts of a device, eg, the whole device
1291 * when formatting. Splitting these large discards up into cache block
1292 * sized ios and then quiescing (always neccessary for discard) takes too
1293 * long.
1294 *
1295 * We keep it simple, and allow any size of discard to come in, and just
1296 * mark off blocks on the discard bitset. No passdown occurs!
1297 *
1298 * To implement passdown we need to change the bio_prison such that a cell
1299 * can have a key that spans many blocks.
1300 */
1301static void process_discard_bio(struct cache *cache, struct bio *bio)
1302{
Kent Overstreet4f024f32013-10-11 15:44:27 -07001303 dm_block_t start_block = dm_sector_div_up(bio->bi_iter.bi_sector,
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04001304 cache->sectors_per_block);
Kent Overstreet4f024f32013-10-11 15:44:27 -07001305 dm_block_t end_block = bio_end_sector(bio);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001306 dm_block_t b;
1307
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04001308 end_block = block_div(end_block, cache->sectors_per_block);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001309
1310 for (b = start_block; b < end_block; b++)
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04001311 set_discard(cache, to_oblock(b));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001312
1313 bio_endio(bio, 0);
1314}
1315
1316static bool spare_migration_bandwidth(struct cache *cache)
1317{
1318 sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) *
1319 cache->sectors_per_block;
1320 return current_volume < cache->migration_threshold;
1321}
1322
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001323static void inc_hit_counter(struct cache *cache, struct bio *bio)
1324{
1325 atomic_inc(bio_data_dir(bio) == READ ?
1326 &cache->stats.read_hit : &cache->stats.write_hit);
1327}
1328
1329static void inc_miss_counter(struct cache *cache, struct bio *bio)
1330{
1331 atomic_inc(bio_data_dir(bio) == READ ?
1332 &cache->stats.read_miss : &cache->stats.write_miss);
1333}
1334
1335static void process_bio(struct cache *cache, struct prealloc *structs,
1336 struct bio *bio)
1337{
1338 int r;
1339 bool release_cell = true;
1340 dm_oblock_t block = get_bio_block(cache, bio);
1341 struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell;
1342 struct policy_result lookup_result;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001343 bool discarded_block = is_discarded_oblock(cache, block);
Joe Thornber2ee57d52013-10-24 14:10:29 -04001344 bool passthrough = passthrough_mode(&cache->features);
1345 bool can_migrate = !passthrough && (discarded_block || spare_migration_bandwidth(cache));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001346
1347 /*
1348 * Check to see if that block is currently migrating.
1349 */
1350 cell_prealloc = prealloc_get_cell(structs);
1351 r = bio_detain(cache, block, bio, cell_prealloc,
1352 (cell_free_fn) prealloc_put_cell,
1353 structs, &new_ocell);
1354 if (r > 0)
1355 return;
1356
1357 r = policy_map(cache->policy, block, true, can_migrate, discarded_block,
1358 bio, &lookup_result);
1359
1360 if (r == -EWOULDBLOCK)
1361 /* migration has been denied */
1362 lookup_result.op = POLICY_MISS;
1363
1364 switch (lookup_result.op) {
1365 case POLICY_HIT:
Joe Thornber2ee57d52013-10-24 14:10:29 -04001366 if (passthrough) {
1367 inc_miss_counter(cache, bio);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001368
Joe Thornber2ee57d52013-10-24 14:10:29 -04001369 /*
1370 * Passthrough always maps to the origin,
1371 * invalidating any cache blocks that are written
1372 * to.
1373 */
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001374
Joe Thornber2ee57d52013-10-24 14:10:29 -04001375 if (bio_data_dir(bio) == WRITE) {
1376 atomic_inc(&cache->stats.demotion);
1377 invalidate(cache, structs, block, lookup_result.cblock, new_ocell);
1378 release_cell = false;
1379
1380 } else {
1381 /* FIXME: factor out issue_origin() */
Joe Thornber2ee57d52013-10-24 14:10:29 -04001382 remap_to_origin_clear_discard(cache, bio, block);
Joe Thornber8c081b52014-05-13 16:18:38 +01001383 inc_and_issue(cache, bio, new_ocell);
Joe Thornber2ee57d52013-10-24 14:10:29 -04001384 }
1385 } else {
1386 inc_hit_counter(cache, bio);
1387
1388 if (bio_data_dir(bio) == WRITE &&
1389 writethrough_mode(&cache->features) &&
1390 !is_dirty(cache, lookup_result.cblock)) {
Joe Thornber2ee57d52013-10-24 14:10:29 -04001391 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
Joe Thornber8c081b52014-05-13 16:18:38 +01001392 inc_and_issue(cache, bio, new_ocell);
1393
1394 } else {
1395 remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
1396 inc_and_issue(cache, bio, new_ocell);
1397 }
Joe Thornber2ee57d52013-10-24 14:10:29 -04001398 }
1399
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001400 break;
1401
1402 case POLICY_MISS:
1403 inc_miss_counter(cache, bio);
Joe Thornbere2e74d62013-03-20 17:21:27 +00001404 remap_to_origin_clear_discard(cache, bio, block);
Joe Thornber8c081b52014-05-13 16:18:38 +01001405 inc_and_issue(cache, bio, new_ocell);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001406 break;
1407
1408 case POLICY_NEW:
1409 atomic_inc(&cache->stats.promotion);
1410 promote(cache, structs, block, lookup_result.cblock, new_ocell);
1411 release_cell = false;
1412 break;
1413
1414 case POLICY_REPLACE:
1415 cell_prealloc = prealloc_get_cell(structs);
1416 r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc,
1417 (cell_free_fn) prealloc_put_cell,
1418 structs, &old_ocell);
1419 if (r > 0) {
1420 /*
1421 * We have to be careful to avoid lock inversion of
1422 * the cells. So we back off, and wait for the
1423 * old_ocell to become free.
1424 */
1425 policy_force_mapping(cache->policy, block,
1426 lookup_result.old_oblock);
1427 atomic_inc(&cache->stats.cache_cell_clash);
1428 break;
1429 }
1430 atomic_inc(&cache->stats.demotion);
1431 atomic_inc(&cache->stats.promotion);
1432
1433 demote_then_promote(cache, structs, lookup_result.old_oblock,
1434 block, lookup_result.cblock,
1435 old_ocell, new_ocell);
1436 release_cell = false;
1437 break;
1438
1439 default:
1440 DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__,
1441 (unsigned) lookup_result.op);
1442 bio_io_error(bio);
1443 }
1444
1445 if (release_cell)
1446 cell_defer(cache, new_ocell, false);
1447}
1448
1449static int need_commit_due_to_time(struct cache *cache)
1450{
1451 return jiffies < cache->last_commit_jiffies ||
1452 jiffies > cache->last_commit_jiffies + COMMIT_PERIOD;
1453}
1454
1455static int commit_if_needed(struct cache *cache)
1456{
Heinz Mauelshagenffcbcb62013-10-14 17:24:43 +02001457 int r = 0;
1458
1459 if ((cache->commit_requested || need_commit_due_to_time(cache)) &&
1460 dm_cache_changed_this_transaction(cache->cmd)) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001461 atomic_inc(&cache->stats.commit_count);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001462 cache->commit_requested = false;
Heinz Mauelshagenffcbcb62013-10-14 17:24:43 +02001463 r = dm_cache_commit(cache->cmd, false);
1464 cache->last_commit_jiffies = jiffies;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001465 }
1466
Heinz Mauelshagenffcbcb62013-10-14 17:24:43 +02001467 return r;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001468}
1469
1470static void process_deferred_bios(struct cache *cache)
1471{
1472 unsigned long flags;
1473 struct bio_list bios;
1474 struct bio *bio;
1475 struct prealloc structs;
1476
1477 memset(&structs, 0, sizeof(structs));
1478 bio_list_init(&bios);
1479
1480 spin_lock_irqsave(&cache->lock, flags);
1481 bio_list_merge(&bios, &cache->deferred_bios);
1482 bio_list_init(&cache->deferred_bios);
1483 spin_unlock_irqrestore(&cache->lock, flags);
1484
1485 while (!bio_list_empty(&bios)) {
1486 /*
1487 * If we've got no free migration structs, and processing
1488 * this bio might require one, we pause until there are some
1489 * prepared mappings to process.
1490 */
1491 if (prealloc_data_structs(cache, &structs)) {
1492 spin_lock_irqsave(&cache->lock, flags);
1493 bio_list_merge(&cache->deferred_bios, &bios);
1494 spin_unlock_irqrestore(&cache->lock, flags);
1495 break;
1496 }
1497
1498 bio = bio_list_pop(&bios);
1499
1500 if (bio->bi_rw & REQ_FLUSH)
1501 process_flush_bio(cache, bio);
1502 else if (bio->bi_rw & REQ_DISCARD)
1503 process_discard_bio(cache, bio);
1504 else
1505 process_bio(cache, &structs, bio);
1506 }
1507
1508 prealloc_free_structs(cache, &structs);
1509}
1510
1511static void process_deferred_flush_bios(struct cache *cache, bool submit_bios)
1512{
1513 unsigned long flags;
1514 struct bio_list bios;
1515 struct bio *bio;
1516
1517 bio_list_init(&bios);
1518
1519 spin_lock_irqsave(&cache->lock, flags);
1520 bio_list_merge(&bios, &cache->deferred_flush_bios);
1521 bio_list_init(&cache->deferred_flush_bios);
1522 spin_unlock_irqrestore(&cache->lock, flags);
1523
Joe Thornber8c081b52014-05-13 16:18:38 +01001524 /*
1525 * These bios have already been through inc_ds()
1526 */
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001527 while ((bio = bio_list_pop(&bios)))
1528 submit_bios ? generic_make_request(bio) : bio_io_error(bio);
1529}
1530
Joe Thornbere2e74d62013-03-20 17:21:27 +00001531static void process_deferred_writethrough_bios(struct cache *cache)
1532{
1533 unsigned long flags;
1534 struct bio_list bios;
1535 struct bio *bio;
1536
1537 bio_list_init(&bios);
1538
1539 spin_lock_irqsave(&cache->lock, flags);
1540 bio_list_merge(&bios, &cache->deferred_writethrough_bios);
1541 bio_list_init(&cache->deferred_writethrough_bios);
1542 spin_unlock_irqrestore(&cache->lock, flags);
1543
Joe Thornber8c081b52014-05-13 16:18:38 +01001544 /*
1545 * These bios have already been through inc_ds()
1546 */
Joe Thornbere2e74d62013-03-20 17:21:27 +00001547 while ((bio = bio_list_pop(&bios)))
1548 generic_make_request(bio);
1549}
1550
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001551static void writeback_some_dirty_blocks(struct cache *cache)
1552{
1553 int r = 0;
1554 dm_oblock_t oblock;
1555 dm_cblock_t cblock;
1556 struct prealloc structs;
1557 struct dm_bio_prison_cell *old_ocell;
1558
1559 memset(&structs, 0, sizeof(structs));
1560
1561 while (spare_migration_bandwidth(cache)) {
1562 if (prealloc_data_structs(cache, &structs))
1563 break;
1564
1565 r = policy_writeback_work(cache->policy, &oblock, &cblock);
1566 if (r)
1567 break;
1568
1569 r = get_cell(cache, oblock, &structs, &old_ocell);
1570 if (r) {
1571 policy_set_dirty(cache->policy, oblock);
1572 break;
1573 }
1574
1575 writeback(cache, &structs, oblock, cblock, old_ocell);
1576 }
1577
1578 prealloc_free_structs(cache, &structs);
1579}
1580
1581/*----------------------------------------------------------------
Joe Thornber65790ff2013-11-08 16:39:50 +00001582 * Invalidations.
1583 * Dropping something from the cache *without* writing back.
1584 *--------------------------------------------------------------*/
1585
1586static void process_invalidation_request(struct cache *cache, struct invalidation_request *req)
1587{
1588 int r = 0;
1589 uint64_t begin = from_cblock(req->cblocks->begin);
1590 uint64_t end = from_cblock(req->cblocks->end);
1591
1592 while (begin != end) {
1593 r = policy_remove_cblock(cache->policy, to_cblock(begin));
1594 if (!r) {
1595 r = dm_cache_remove_mapping(cache->cmd, to_cblock(begin));
1596 if (r)
1597 break;
1598
1599 } else if (r == -ENODATA) {
1600 /* harmless, already unmapped */
1601 r = 0;
1602
1603 } else {
1604 DMERR("policy_remove_cblock failed");
1605 break;
1606 }
1607
1608 begin++;
1609 }
1610
1611 cache->commit_requested = true;
1612
1613 req->err = r;
1614 atomic_set(&req->complete, 1);
1615
1616 wake_up(&req->result_wait);
1617}
1618
1619static void process_invalidation_requests(struct cache *cache)
1620{
1621 struct list_head list;
1622 struct invalidation_request *req, *tmp;
1623
1624 INIT_LIST_HEAD(&list);
1625 spin_lock(&cache->invalidation_lock);
1626 list_splice_init(&cache->invalidation_requests, &list);
1627 spin_unlock(&cache->invalidation_lock);
1628
1629 list_for_each_entry_safe (req, tmp, &list, list)
1630 process_invalidation_request(cache, req);
1631}
1632
1633/*----------------------------------------------------------------
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001634 * Main worker loop
1635 *--------------------------------------------------------------*/
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001636static bool is_quiescing(struct cache *cache)
1637{
Joe Thornber238f8362013-10-30 17:29:30 +00001638 return atomic_read(&cache->quiescing);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001639}
1640
Joe Thornber66cb1912013-10-30 17:11:58 +00001641static void ack_quiescing(struct cache *cache)
1642{
1643 if (is_quiescing(cache)) {
1644 atomic_inc(&cache->quiescing_ack);
1645 wake_up(&cache->quiescing_wait);
1646 }
1647}
1648
1649static void wait_for_quiescing_ack(struct cache *cache)
1650{
1651 wait_event(cache->quiescing_wait, atomic_read(&cache->quiescing_ack));
1652}
1653
1654static void start_quiescing(struct cache *cache)
1655{
Joe Thornber238f8362013-10-30 17:29:30 +00001656 atomic_inc(&cache->quiescing);
Joe Thornber66cb1912013-10-30 17:11:58 +00001657 wait_for_quiescing_ack(cache);
1658}
1659
1660static void stop_quiescing(struct cache *cache)
1661{
Joe Thornber238f8362013-10-30 17:29:30 +00001662 atomic_set(&cache->quiescing, 0);
Joe Thornber66cb1912013-10-30 17:11:58 +00001663 atomic_set(&cache->quiescing_ack, 0);
1664}
1665
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001666static void wait_for_migrations(struct cache *cache)
1667{
1668 wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations));
1669}
1670
1671static void stop_worker(struct cache *cache)
1672{
1673 cancel_delayed_work(&cache->waker);
1674 flush_workqueue(cache->wq);
1675}
1676
1677static void requeue_deferred_io(struct cache *cache)
1678{
1679 struct bio *bio;
1680 struct bio_list bios;
1681
1682 bio_list_init(&bios);
1683 bio_list_merge(&bios, &cache->deferred_bios);
1684 bio_list_init(&cache->deferred_bios);
1685
1686 while ((bio = bio_list_pop(&bios)))
1687 bio_endio(bio, DM_ENDIO_REQUEUE);
1688}
1689
1690static int more_work(struct cache *cache)
1691{
1692 if (is_quiescing(cache))
1693 return !list_empty(&cache->quiesced_migrations) ||
1694 !list_empty(&cache->completed_migrations) ||
1695 !list_empty(&cache->need_commit_migrations);
1696 else
1697 return !bio_list_empty(&cache->deferred_bios) ||
1698 !bio_list_empty(&cache->deferred_flush_bios) ||
Joe Thornbere2e74d62013-03-20 17:21:27 +00001699 !bio_list_empty(&cache->deferred_writethrough_bios) ||
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001700 !list_empty(&cache->quiesced_migrations) ||
1701 !list_empty(&cache->completed_migrations) ||
Joe Thornber65790ff2013-11-08 16:39:50 +00001702 !list_empty(&cache->need_commit_migrations) ||
1703 cache->invalidate;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001704}
1705
1706static void do_worker(struct work_struct *ws)
1707{
1708 struct cache *cache = container_of(ws, struct cache, worker);
1709
1710 do {
Joe Thornber66cb1912013-10-30 17:11:58 +00001711 if (!is_quiescing(cache)) {
1712 writeback_some_dirty_blocks(cache);
1713 process_deferred_writethrough_bios(cache);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001714 process_deferred_bios(cache);
Joe Thornber65790ff2013-11-08 16:39:50 +00001715 process_invalidation_requests(cache);
Joe Thornber66cb1912013-10-30 17:11:58 +00001716 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001717
1718 process_migrations(cache, &cache->quiesced_migrations, issue_copy);
1719 process_migrations(cache, &cache->completed_migrations, complete_migration);
1720
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001721 if (commit_if_needed(cache)) {
1722 process_deferred_flush_bios(cache, false);
Joe Thornber304affa2014-06-24 15:36:58 -04001723 process_migrations(cache, &cache->need_commit_migrations, migration_failure);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001724
1725 /*
1726 * FIXME: rollback metadata or just go into a
1727 * failure mode and error everything
1728 */
1729 } else {
1730 process_deferred_flush_bios(cache, true);
1731 process_migrations(cache, &cache->need_commit_migrations,
1732 migration_success_post_commit);
1733 }
Joe Thornber66cb1912013-10-30 17:11:58 +00001734
1735 ack_quiescing(cache);
1736
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001737 } while (more_work(cache));
1738}
1739
1740/*
1741 * We want to commit periodically so that not too much
1742 * unwritten metadata builds up.
1743 */
1744static void do_waker(struct work_struct *ws)
1745{
1746 struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker);
Joe Thornberf8350da2013-05-10 14:37:16 +01001747 policy_tick(cache->policy);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001748 wake_worker(cache);
1749 queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD);
1750}
1751
1752/*----------------------------------------------------------------*/
1753
1754static int is_congested(struct dm_dev *dev, int bdi_bits)
1755{
1756 struct request_queue *q = bdev_get_queue(dev->bdev);
1757 return bdi_congested(&q->backing_dev_info, bdi_bits);
1758}
1759
1760static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1761{
1762 struct cache *cache = container_of(cb, struct cache, callbacks);
1763
1764 return is_congested(cache->origin_dev, bdi_bits) ||
1765 is_congested(cache->cache_dev, bdi_bits);
1766}
1767
1768/*----------------------------------------------------------------
1769 * Target methods
1770 *--------------------------------------------------------------*/
1771
1772/*
1773 * This function gets called on the error paths of the constructor, so we
1774 * have to cope with a partially initialised struct.
1775 */
1776static void destroy(struct cache *cache)
1777{
1778 unsigned i;
1779
1780 if (cache->next_migration)
1781 mempool_free(cache->next_migration, cache->migration_pool);
1782
1783 if (cache->migration_pool)
1784 mempool_destroy(cache->migration_pool);
1785
1786 if (cache->all_io_ds)
1787 dm_deferred_set_destroy(cache->all_io_ds);
1788
1789 if (cache->prison)
1790 dm_bio_prison_destroy(cache->prison);
1791
1792 if (cache->wq)
1793 destroy_workqueue(cache->wq);
1794
1795 if (cache->dirty_bitset)
1796 free_bitset(cache->dirty_bitset);
1797
1798 if (cache->discard_bitset)
1799 free_bitset(cache->discard_bitset);
1800
1801 if (cache->copier)
1802 dm_kcopyd_client_destroy(cache->copier);
1803
1804 if (cache->cmd)
1805 dm_cache_metadata_close(cache->cmd);
1806
1807 if (cache->metadata_dev)
1808 dm_put_device(cache->ti, cache->metadata_dev);
1809
1810 if (cache->origin_dev)
1811 dm_put_device(cache->ti, cache->origin_dev);
1812
1813 if (cache->cache_dev)
1814 dm_put_device(cache->ti, cache->cache_dev);
1815
1816 if (cache->policy)
1817 dm_cache_policy_destroy(cache->policy);
1818
1819 for (i = 0; i < cache->nr_ctr_args ; i++)
1820 kfree(cache->ctr_args[i]);
1821 kfree(cache->ctr_args);
1822
1823 kfree(cache);
1824}
1825
1826static void cache_dtr(struct dm_target *ti)
1827{
1828 struct cache *cache = ti->private;
1829
1830 destroy(cache);
1831}
1832
1833static sector_t get_dev_size(struct dm_dev *dev)
1834{
1835 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
1836}
1837
1838/*----------------------------------------------------------------*/
1839
1840/*
1841 * Construct a cache device mapping.
1842 *
1843 * cache <metadata dev> <cache dev> <origin dev> <block size>
1844 * <#feature args> [<feature arg>]*
1845 * <policy> <#policy args> [<policy arg>]*
1846 *
1847 * metadata dev : fast device holding the persistent metadata
1848 * cache dev : fast device holding cached data blocks
1849 * origin dev : slow device holding original data blocks
1850 * block size : cache unit size in sectors
1851 *
1852 * #feature args : number of feature arguments passed
1853 * feature args : writethrough. (The default is writeback.)
1854 *
1855 * policy : the replacement policy to use
1856 * #policy args : an even number of policy arguments corresponding
1857 * to key/value pairs passed to the policy
1858 * policy args : key/value pairs passed to the policy
1859 * E.g. 'sequential_threshold 1024'
1860 * See cache-policies.txt for details.
1861 *
1862 * Optional feature arguments are:
1863 * writethrough : write through caching that prohibits cache block
1864 * content from being different from origin block content.
1865 * Without this argument, the default behaviour is to write
1866 * back cache block contents later for performance reasons,
1867 * so they may differ from the corresponding origin blocks.
1868 */
1869struct cache_args {
1870 struct dm_target *ti;
1871
1872 struct dm_dev *metadata_dev;
1873
1874 struct dm_dev *cache_dev;
1875 sector_t cache_sectors;
1876
1877 struct dm_dev *origin_dev;
1878 sector_t origin_sectors;
1879
1880 uint32_t block_size;
1881
1882 const char *policy_name;
1883 int policy_argc;
1884 const char **policy_argv;
1885
1886 struct cache_features features;
1887};
1888
1889static void destroy_cache_args(struct cache_args *ca)
1890{
1891 if (ca->metadata_dev)
1892 dm_put_device(ca->ti, ca->metadata_dev);
1893
1894 if (ca->cache_dev)
1895 dm_put_device(ca->ti, ca->cache_dev);
1896
1897 if (ca->origin_dev)
1898 dm_put_device(ca->ti, ca->origin_dev);
1899
1900 kfree(ca);
1901}
1902
1903static bool at_least_one_arg(struct dm_arg_set *as, char **error)
1904{
1905 if (!as->argc) {
1906 *error = "Insufficient args";
1907 return false;
1908 }
1909
1910 return true;
1911}
1912
1913static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as,
1914 char **error)
1915{
1916 int r;
1917 sector_t metadata_dev_size;
1918 char b[BDEVNAME_SIZE];
1919
1920 if (!at_least_one_arg(as, error))
1921 return -EINVAL;
1922
1923 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
1924 &ca->metadata_dev);
1925 if (r) {
1926 *error = "Error opening metadata device";
1927 return r;
1928 }
1929
1930 metadata_dev_size = get_dev_size(ca->metadata_dev);
1931 if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING)
1932 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1933 bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
1934
1935 return 0;
1936}
1937
1938static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as,
1939 char **error)
1940{
1941 int r;
1942
1943 if (!at_least_one_arg(as, error))
1944 return -EINVAL;
1945
1946 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
1947 &ca->cache_dev);
1948 if (r) {
1949 *error = "Error opening cache device";
1950 return r;
1951 }
1952 ca->cache_sectors = get_dev_size(ca->cache_dev);
1953
1954 return 0;
1955}
1956
1957static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as,
1958 char **error)
1959{
1960 int r;
1961
1962 if (!at_least_one_arg(as, error))
1963 return -EINVAL;
1964
1965 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
1966 &ca->origin_dev);
1967 if (r) {
1968 *error = "Error opening origin device";
1969 return r;
1970 }
1971
1972 ca->origin_sectors = get_dev_size(ca->origin_dev);
1973 if (ca->ti->len > ca->origin_sectors) {
1974 *error = "Device size larger than cached device";
1975 return -EINVAL;
1976 }
1977
1978 return 0;
1979}
1980
1981static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as,
1982 char **error)
1983{
Mike Snitzer05473042013-08-16 10:54:19 -04001984 unsigned long block_size;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001985
1986 if (!at_least_one_arg(as, error))
1987 return -EINVAL;
1988
Mike Snitzer05473042013-08-16 10:54:19 -04001989 if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size ||
1990 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
1991 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
1992 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001993 *error = "Invalid data block size";
1994 return -EINVAL;
1995 }
1996
Mike Snitzer05473042013-08-16 10:54:19 -04001997 if (block_size > ca->cache_sectors) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001998 *error = "Data block size is larger than the cache device";
1999 return -EINVAL;
2000 }
2001
Mike Snitzer05473042013-08-16 10:54:19 -04002002 ca->block_size = block_size;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002003
2004 return 0;
2005}
2006
2007static void init_features(struct cache_features *cf)
2008{
2009 cf->mode = CM_WRITE;
Joe Thornber2ee57d52013-10-24 14:10:29 -04002010 cf->io_mode = CM_IO_WRITEBACK;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002011}
2012
2013static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
2014 char **error)
2015{
2016 static struct dm_arg _args[] = {
2017 {0, 1, "Invalid number of cache feature arguments"},
2018 };
2019
2020 int r;
2021 unsigned argc;
2022 const char *arg;
2023 struct cache_features *cf = &ca->features;
2024
2025 init_features(cf);
2026
2027 r = dm_read_arg_group(_args, as, &argc, error);
2028 if (r)
2029 return -EINVAL;
2030
2031 while (argc--) {
2032 arg = dm_shift_arg(as);
2033
2034 if (!strcasecmp(arg, "writeback"))
Joe Thornber2ee57d52013-10-24 14:10:29 -04002035 cf->io_mode = CM_IO_WRITEBACK;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002036
2037 else if (!strcasecmp(arg, "writethrough"))
Joe Thornber2ee57d52013-10-24 14:10:29 -04002038 cf->io_mode = CM_IO_WRITETHROUGH;
2039
2040 else if (!strcasecmp(arg, "passthrough"))
2041 cf->io_mode = CM_IO_PASSTHROUGH;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002042
2043 else {
2044 *error = "Unrecognised cache feature requested";
2045 return -EINVAL;
2046 }
2047 }
2048
2049 return 0;
2050}
2051
2052static int parse_policy(struct cache_args *ca, struct dm_arg_set *as,
2053 char **error)
2054{
2055 static struct dm_arg _args[] = {
2056 {0, 1024, "Invalid number of policy arguments"},
2057 };
2058
2059 int r;
2060
2061 if (!at_least_one_arg(as, error))
2062 return -EINVAL;
2063
2064 ca->policy_name = dm_shift_arg(as);
2065
2066 r = dm_read_arg_group(_args, as, &ca->policy_argc, error);
2067 if (r)
2068 return -EINVAL;
2069
2070 ca->policy_argv = (const char **)as->argv;
2071 dm_consume_args(as, ca->policy_argc);
2072
2073 return 0;
2074}
2075
2076static int parse_cache_args(struct cache_args *ca, int argc, char **argv,
2077 char **error)
2078{
2079 int r;
2080 struct dm_arg_set as;
2081
2082 as.argc = argc;
2083 as.argv = argv;
2084
2085 r = parse_metadata_dev(ca, &as, error);
2086 if (r)
2087 return r;
2088
2089 r = parse_cache_dev(ca, &as, error);
2090 if (r)
2091 return r;
2092
2093 r = parse_origin_dev(ca, &as, error);
2094 if (r)
2095 return r;
2096
2097 r = parse_block_size(ca, &as, error);
2098 if (r)
2099 return r;
2100
2101 r = parse_features(ca, &as, error);
2102 if (r)
2103 return r;
2104
2105 r = parse_policy(ca, &as, error);
2106 if (r)
2107 return r;
2108
2109 return 0;
2110}
2111
2112/*----------------------------------------------------------------*/
2113
2114static struct kmem_cache *migration_cache;
2115
Alasdair G Kergon2c73c472013-05-10 14:37:21 +01002116#define NOT_CORE_OPTION 1
2117
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002118static int process_config_option(struct cache *cache, const char *key, const char *value)
Alasdair G Kergon2c73c472013-05-10 14:37:21 +01002119{
2120 unsigned long tmp;
2121
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002122 if (!strcasecmp(key, "migration_threshold")) {
2123 if (kstrtoul(value, 10, &tmp))
Alasdair G Kergon2c73c472013-05-10 14:37:21 +01002124 return -EINVAL;
2125
2126 cache->migration_threshold = tmp;
2127 return 0;
2128 }
2129
2130 return NOT_CORE_OPTION;
2131}
2132
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002133static int set_config_value(struct cache *cache, const char *key, const char *value)
2134{
2135 int r = process_config_option(cache, key, value);
2136
2137 if (r == NOT_CORE_OPTION)
2138 r = policy_set_config_value(cache->policy, key, value);
2139
2140 if (r)
2141 DMWARN("bad config value for %s: %s", key, value);
2142
2143 return r;
2144}
2145
2146static int set_config_values(struct cache *cache, int argc, const char **argv)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002147{
2148 int r = 0;
2149
2150 if (argc & 1) {
2151 DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs.");
2152 return -EINVAL;
2153 }
2154
2155 while (argc) {
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002156 r = set_config_value(cache, argv[0], argv[1]);
2157 if (r)
2158 break;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002159
2160 argc -= 2;
2161 argv += 2;
2162 }
2163
2164 return r;
2165}
2166
2167static int create_cache_policy(struct cache *cache, struct cache_args *ca,
2168 char **error)
2169{
Mikulas Patocka4cb3e1d2013-10-01 18:35:39 -04002170 struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name,
2171 cache->cache_size,
2172 cache->origin_sectors,
2173 cache->sectors_per_block);
2174 if (IS_ERR(p)) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002175 *error = "Error creating cache's policy";
Mikulas Patocka4cb3e1d2013-10-01 18:35:39 -04002176 return PTR_ERR(p);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002177 }
Mikulas Patocka4cb3e1d2013-10-01 18:35:39 -04002178 cache->policy = p;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002179
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002180 return 0;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002181}
2182
Joe Thornberf8350da2013-05-10 14:37:16 +01002183#define DEFAULT_MIGRATION_THRESHOLD 2048
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002184
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002185static int cache_create(struct cache_args *ca, struct cache **result)
2186{
2187 int r = 0;
2188 char **error = &ca->ti->error;
2189 struct cache *cache;
2190 struct dm_target *ti = ca->ti;
2191 dm_block_t origin_blocks;
2192 struct dm_cache_metadata *cmd;
2193 bool may_format = ca->features.mode == CM_WRITE;
2194
2195 cache = kzalloc(sizeof(*cache), GFP_KERNEL);
2196 if (!cache)
2197 return -ENOMEM;
2198
2199 cache->ti = ca->ti;
2200 ti->private = cache;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002201 ti->num_flush_bios = 2;
2202 ti->flush_supported = true;
2203
2204 ti->num_discard_bios = 1;
2205 ti->discards_supported = true;
2206 ti->discard_zeroes_data_unsupported = true;
Heinz Mauelshagenf1daa8382014-05-23 14:10:01 -04002207 /* Discard bios must be split on a block boundary */
2208 ti->split_discard_bios = true;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002209
Joe Thornber8c5008f2013-05-10 14:37:18 +01002210 cache->features = ca->features;
Mike Snitzer19b00922013-04-05 15:36:34 +01002211 ti->per_bio_data_size = get_per_bio_data_size(cache);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002212
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002213 cache->callbacks.congested_fn = cache_is_congested;
2214 dm_table_add_target_callbacks(ti->table, &cache->callbacks);
2215
2216 cache->metadata_dev = ca->metadata_dev;
2217 cache->origin_dev = ca->origin_dev;
2218 cache->cache_dev = ca->cache_dev;
2219
2220 ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL;
2221
2222 /* FIXME: factor out this whole section */
2223 origin_blocks = cache->origin_sectors = ca->origin_sectors;
Joe Thornber414dd672013-03-20 17:21:25 +00002224 origin_blocks = block_div(origin_blocks, ca->block_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002225 cache->origin_blocks = to_oblock(origin_blocks);
2226
2227 cache->sectors_per_block = ca->block_size;
2228 if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) {
2229 r = -EINVAL;
2230 goto bad;
2231 }
2232
2233 if (ca->block_size & (ca->block_size - 1)) {
2234 dm_block_t cache_size = ca->cache_sectors;
2235
2236 cache->sectors_per_block_shift = -1;
Joe Thornber414dd672013-03-20 17:21:25 +00002237 cache_size = block_div(cache_size, ca->block_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002238 cache->cache_size = to_cblock(cache_size);
2239 } else {
2240 cache->sectors_per_block_shift = __ffs(ca->block_size);
2241 cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift);
2242 }
2243
2244 r = create_cache_policy(cache, ca, error);
2245 if (r)
2246 goto bad;
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002247
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002248 cache->policy_nr_args = ca->policy_argc;
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002249 cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD;
2250
2251 r = set_config_values(cache, ca->policy_argc, ca->policy_argv);
2252 if (r) {
2253 *error = "Error setting cache policy's config values";
2254 goto bad;
2255 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002256
2257 cmd = dm_cache_metadata_open(cache->metadata_dev->bdev,
2258 ca->block_size, may_format,
2259 dm_cache_policy_get_hint_size(cache->policy));
2260 if (IS_ERR(cmd)) {
2261 *error = "Error creating metadata object";
2262 r = PTR_ERR(cmd);
2263 goto bad;
2264 }
2265 cache->cmd = cmd;
2266
Joe Thornber2ee57d52013-10-24 14:10:29 -04002267 if (passthrough_mode(&cache->features)) {
2268 bool all_clean;
2269
2270 r = dm_cache_metadata_all_clean(cache->cmd, &all_clean);
2271 if (r) {
2272 *error = "dm_cache_metadata_all_clean() failed";
2273 goto bad;
2274 }
2275
2276 if (!all_clean) {
2277 *error = "Cannot enter passthrough mode unless all blocks are clean";
2278 r = -EINVAL;
2279 goto bad;
2280 }
2281 }
2282
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002283 spin_lock_init(&cache->lock);
2284 bio_list_init(&cache->deferred_bios);
2285 bio_list_init(&cache->deferred_flush_bios);
Joe Thornbere2e74d62013-03-20 17:21:27 +00002286 bio_list_init(&cache->deferred_writethrough_bios);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002287 INIT_LIST_HEAD(&cache->quiesced_migrations);
2288 INIT_LIST_HEAD(&cache->completed_migrations);
2289 INIT_LIST_HEAD(&cache->need_commit_migrations);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002290 atomic_set(&cache->nr_migrations, 0);
2291 init_waitqueue_head(&cache->migration_wait);
2292
Joe Thornber66cb1912013-10-30 17:11:58 +00002293 init_waitqueue_head(&cache->quiescing_wait);
Joe Thornber238f8362013-10-30 17:29:30 +00002294 atomic_set(&cache->quiescing, 0);
Joe Thornber66cb1912013-10-30 17:11:58 +00002295 atomic_set(&cache->quiescing_ack, 0);
2296
Wei Yongjunfa4d6832013-05-10 14:37:14 +01002297 r = -ENOMEM;
Anssi Hannula44fa8162014-08-01 11:55:47 -04002298 atomic_set(&cache->nr_dirty, 0);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002299 cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size));
2300 if (!cache->dirty_bitset) {
2301 *error = "could not allocate dirty bitset";
2302 goto bad;
2303 }
2304 clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
2305
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002306 cache->discard_nr_blocks = cache->origin_blocks;
2307 cache->discard_bitset = alloc_bitset(from_oblock(cache->discard_nr_blocks));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002308 if (!cache->discard_bitset) {
2309 *error = "could not allocate discard bitset";
2310 goto bad;
2311 }
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002312 clear_bitset(cache->discard_bitset, from_oblock(cache->discard_nr_blocks));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002313
2314 cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2315 if (IS_ERR(cache->copier)) {
2316 *error = "could not create kcopyd client";
2317 r = PTR_ERR(cache->copier);
2318 goto bad;
2319 }
2320
2321 cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2322 if (!cache->wq) {
2323 *error = "could not create workqueue for metadata object";
2324 goto bad;
2325 }
2326 INIT_WORK(&cache->worker, do_worker);
2327 INIT_DELAYED_WORK(&cache->waker, do_waker);
2328 cache->last_commit_jiffies = jiffies;
2329
2330 cache->prison = dm_bio_prison_create(PRISON_CELLS);
2331 if (!cache->prison) {
2332 *error = "could not create bio prison";
2333 goto bad;
2334 }
2335
2336 cache->all_io_ds = dm_deferred_set_create();
2337 if (!cache->all_io_ds) {
2338 *error = "could not create all_io deferred set";
2339 goto bad;
2340 }
2341
2342 cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE,
2343 migration_cache);
2344 if (!cache->migration_pool) {
2345 *error = "Error creating cache's migration mempool";
2346 goto bad;
2347 }
2348
2349 cache->next_migration = NULL;
2350
2351 cache->need_tick_bio = true;
2352 cache->sized = false;
Joe Thornber65790ff2013-11-08 16:39:50 +00002353 cache->invalidate = false;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002354 cache->commit_requested = false;
2355 cache->loaded_mappings = false;
2356 cache->loaded_discards = false;
2357
2358 load_stats(cache);
2359
2360 atomic_set(&cache->stats.demotion, 0);
2361 atomic_set(&cache->stats.promotion, 0);
2362 atomic_set(&cache->stats.copies_avoided, 0);
2363 atomic_set(&cache->stats.cache_cell_clash, 0);
2364 atomic_set(&cache->stats.commit_count, 0);
2365 atomic_set(&cache->stats.discard_count, 0);
2366
Joe Thornber65790ff2013-11-08 16:39:50 +00002367 spin_lock_init(&cache->invalidation_lock);
2368 INIT_LIST_HEAD(&cache->invalidation_requests);
2369
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002370 *result = cache;
2371 return 0;
2372
2373bad:
2374 destroy(cache);
2375 return r;
2376}
2377
2378static int copy_ctr_args(struct cache *cache, int argc, const char **argv)
2379{
2380 unsigned i;
2381 const char **copy;
2382
2383 copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL);
2384 if (!copy)
2385 return -ENOMEM;
2386 for (i = 0; i < argc; i++) {
2387 copy[i] = kstrdup(argv[i], GFP_KERNEL);
2388 if (!copy[i]) {
2389 while (i--)
2390 kfree(copy[i]);
2391 kfree(copy);
2392 return -ENOMEM;
2393 }
2394 }
2395
2396 cache->nr_ctr_args = argc;
2397 cache->ctr_args = copy;
2398
2399 return 0;
2400}
2401
2402static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv)
2403{
2404 int r = -EINVAL;
2405 struct cache_args *ca;
2406 struct cache *cache = NULL;
2407
2408 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2409 if (!ca) {
2410 ti->error = "Error allocating memory for cache";
2411 return -ENOMEM;
2412 }
2413 ca->ti = ti;
2414
2415 r = parse_cache_args(ca, argc, argv, &ti->error);
2416 if (r)
2417 goto out;
2418
2419 r = cache_create(ca, &cache);
Heinz Mauelshagen617a0b82013-03-20 17:21:26 +00002420 if (r)
2421 goto out;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002422
2423 r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3);
2424 if (r) {
2425 destroy(cache);
2426 goto out;
2427 }
2428
2429 ti->private = cache;
2430
2431out:
2432 destroy_cache_args(ca);
2433 return r;
2434}
2435
Joe Thornber8c081b52014-05-13 16:18:38 +01002436static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell **cell)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002437{
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002438 int r;
2439 dm_oblock_t block = get_bio_block(cache, bio);
Mike Snitzer19b00922013-04-05 15:36:34 +01002440 size_t pb_data_size = get_per_bio_data_size(cache);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002441 bool can_migrate = false;
2442 bool discarded_block;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002443 struct policy_result lookup_result;
Heinz Mauelshagene893fba2014-03-12 16:13:39 +01002444 struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002445
Heinz Mauelshagene893fba2014-03-12 16:13:39 +01002446 if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002447 /*
2448 * This can only occur if the io goes to a partial block at
2449 * the end of the origin device. We don't cache these.
2450 * Just remap to the origin and carry on.
2451 */
Heinz Mauelshagene893fba2014-03-12 16:13:39 +01002452 remap_to_origin(cache, bio);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002453 return DM_MAPIO_REMAPPED;
2454 }
2455
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002456 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) {
2457 defer_bio(cache, bio);
2458 return DM_MAPIO_SUBMITTED;
2459 }
2460
2461 /*
2462 * Check to see if that block is currently migrating.
2463 */
Joe Thornber8c081b52014-05-13 16:18:38 +01002464 *cell = alloc_prison_cell(cache);
2465 if (!*cell) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002466 defer_bio(cache, bio);
2467 return DM_MAPIO_SUBMITTED;
2468 }
2469
Joe Thornber8c081b52014-05-13 16:18:38 +01002470 r = bio_detain(cache, block, bio, *cell,
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002471 (cell_free_fn) free_prison_cell,
Joe Thornber8c081b52014-05-13 16:18:38 +01002472 cache, cell);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002473 if (r) {
2474 if (r < 0)
2475 defer_bio(cache, bio);
2476
2477 return DM_MAPIO_SUBMITTED;
2478 }
2479
2480 discarded_block = is_discarded_oblock(cache, block);
2481
2482 r = policy_map(cache->policy, block, false, can_migrate, discarded_block,
2483 bio, &lookup_result);
2484 if (r == -EWOULDBLOCK) {
Joe Thornber8c081b52014-05-13 16:18:38 +01002485 cell_defer(cache, *cell, true);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002486 return DM_MAPIO_SUBMITTED;
2487
2488 } else if (r) {
2489 DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r);
Joe Thornber8c081b52014-05-13 16:18:38 +01002490 cell_defer(cache, *cell, false);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002491 bio_io_error(bio);
2492 return DM_MAPIO_SUBMITTED;
2493 }
2494
Joe Thornber2ee57d52013-10-24 14:10:29 -04002495 r = DM_MAPIO_REMAPPED;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002496 switch (lookup_result.op) {
2497 case POLICY_HIT:
Joe Thornber2ee57d52013-10-24 14:10:29 -04002498 if (passthrough_mode(&cache->features)) {
2499 if (bio_data_dir(bio) == WRITE) {
2500 /*
2501 * We need to invalidate this block, so
2502 * defer for the worker thread.
2503 */
Joe Thornber8c081b52014-05-13 16:18:38 +01002504 cell_defer(cache, *cell, true);
Joe Thornber2ee57d52013-10-24 14:10:29 -04002505 r = DM_MAPIO_SUBMITTED;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002506
Joe Thornber2ee57d52013-10-24 14:10:29 -04002507 } else {
Joe Thornber2ee57d52013-10-24 14:10:29 -04002508 inc_miss_counter(cache, bio);
2509 remap_to_origin_clear_discard(cache, bio, block);
Joe Thornber2ee57d52013-10-24 14:10:29 -04002510 }
2511
2512 } else {
2513 inc_hit_counter(cache, bio);
Joe Thornber2ee57d52013-10-24 14:10:29 -04002514 if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) &&
2515 !is_dirty(cache, lookup_result.cblock))
2516 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
2517 else
2518 remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
Joe Thornber2ee57d52013-10-24 14:10:29 -04002519 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002520 break;
2521
2522 case POLICY_MISS:
2523 inc_miss_counter(cache, bio);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002524 if (pb->req_nr != 0) {
2525 /*
2526 * This is a duplicate writethrough io that is no
2527 * longer needed because the block has been demoted.
2528 */
2529 bio_endio(bio, 0);
Joe Thornber8c081b52014-05-13 16:18:38 +01002530 cell_defer(cache, *cell, false);
2531 r = DM_MAPIO_SUBMITTED;
2532
2533 } else
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002534 remap_to_origin_clear_discard(cache, bio, block);
Joe Thornber8c081b52014-05-13 16:18:38 +01002535
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002536 break;
2537
2538 default:
2539 DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__,
2540 (unsigned) lookup_result.op);
Joe Thornber8c081b52014-05-13 16:18:38 +01002541 cell_defer(cache, *cell, false);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002542 bio_io_error(bio);
Joe Thornber2ee57d52013-10-24 14:10:29 -04002543 r = DM_MAPIO_SUBMITTED;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002544 }
2545
Joe Thornber2ee57d52013-10-24 14:10:29 -04002546 return r;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002547}
2548
Joe Thornber8c081b52014-05-13 16:18:38 +01002549static int cache_map(struct dm_target *ti, struct bio *bio)
2550{
2551 int r;
2552 struct dm_bio_prison_cell *cell;
2553 struct cache *cache = ti->private;
2554
2555 r = __cache_map(cache, bio, &cell);
2556 if (r == DM_MAPIO_REMAPPED) {
2557 inc_ds(cache, bio, cell);
2558 cell_defer(cache, cell, false);
2559 }
2560
2561 return r;
2562}
2563
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002564static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
2565{
2566 struct cache *cache = ti->private;
2567 unsigned long flags;
Mike Snitzer19b00922013-04-05 15:36:34 +01002568 size_t pb_data_size = get_per_bio_data_size(cache);
2569 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002570
2571 if (pb->tick) {
2572 policy_tick(cache->policy);
2573
2574 spin_lock_irqsave(&cache->lock, flags);
2575 cache->need_tick_bio = true;
2576 spin_unlock_irqrestore(&cache->lock, flags);
2577 }
2578
2579 check_for_quiesced_migrations(cache, pb);
2580
2581 return 0;
2582}
2583
2584static int write_dirty_bitset(struct cache *cache)
2585{
2586 unsigned i, r;
2587
2588 for (i = 0; i < from_cblock(cache->cache_size); i++) {
2589 r = dm_cache_set_dirty(cache->cmd, to_cblock(i),
2590 is_dirty(cache, to_cblock(i)));
2591 if (r)
2592 return r;
2593 }
2594
2595 return 0;
2596}
2597
2598static int write_discard_bitset(struct cache *cache)
2599{
2600 unsigned i, r;
2601
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002602 r = dm_cache_discard_bitset_resize(cache->cmd, cache->sectors_per_block,
2603 cache->origin_blocks);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002604 if (r) {
2605 DMERR("could not resize on-disk discard bitset");
2606 return r;
2607 }
2608
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002609 for (i = 0; i < from_oblock(cache->discard_nr_blocks); i++) {
2610 r = dm_cache_set_discard(cache->cmd, to_oblock(i),
2611 is_discarded(cache, to_oblock(i)));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002612 if (r)
2613 return r;
2614 }
2615
2616 return 0;
2617}
2618
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002619/*
2620 * returns true on success
2621 */
2622static bool sync_metadata(struct cache *cache)
2623{
2624 int r1, r2, r3, r4;
2625
2626 r1 = write_dirty_bitset(cache);
2627 if (r1)
2628 DMERR("could not write dirty bitset");
2629
2630 r2 = write_discard_bitset(cache);
2631 if (r2)
2632 DMERR("could not write discard bitset");
2633
2634 save_stats(cache);
2635
Joe Thornber05966612014-04-03 16:16:44 +01002636 r3 = dm_cache_write_hints(cache->cmd, cache->policy);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002637 if (r3)
2638 DMERR("could not write hints");
2639
2640 /*
2641 * If writing the above metadata failed, we still commit, but don't
2642 * set the clean shutdown flag. This will effectively force every
2643 * dirty bit to be set on reload.
2644 */
2645 r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3);
2646 if (r4)
2647 DMERR("could not write cache metadata. Data loss may occur.");
2648
2649 return !r1 && !r2 && !r3 && !r4;
2650}
2651
2652static void cache_postsuspend(struct dm_target *ti)
2653{
2654 struct cache *cache = ti->private;
2655
2656 start_quiescing(cache);
2657 wait_for_migrations(cache);
2658 stop_worker(cache);
2659 requeue_deferred_io(cache);
2660 stop_quiescing(cache);
2661
2662 (void) sync_metadata(cache);
2663}
2664
2665static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
2666 bool dirty, uint32_t hint, bool hint_valid)
2667{
2668 int r;
2669 struct cache *cache = context;
2670
2671 r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid);
2672 if (r)
2673 return r;
2674
2675 if (dirty)
2676 set_dirty(cache, oblock, cblock);
2677 else
2678 clear_dirty(cache, oblock, cblock);
2679
2680 return 0;
2681}
2682
2683static int load_discard(void *context, sector_t discard_block_size,
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002684 dm_oblock_t oblock, bool discard)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002685{
2686 struct cache *cache = context;
2687
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002688 if (discard)
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002689 set_discard(cache, oblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002690 else
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002691 clear_discard(cache, oblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002692
2693 return 0;
2694}
2695
Joe Thornberf494a9c2013-10-31 13:55:49 -04002696static dm_cblock_t get_cache_dev_size(struct cache *cache)
2697{
2698 sector_t size = get_dev_size(cache->cache_dev);
2699 (void) sector_div(size, cache->sectors_per_block);
2700 return to_cblock(size);
2701}
2702
2703static bool can_resize(struct cache *cache, dm_cblock_t new_size)
2704{
2705 if (from_cblock(new_size) > from_cblock(cache->cache_size))
2706 return true;
2707
2708 /*
2709 * We can't drop a dirty block when shrinking the cache.
2710 */
2711 while (from_cblock(new_size) < from_cblock(cache->cache_size)) {
2712 new_size = to_cblock(from_cblock(new_size) + 1);
2713 if (is_dirty(cache, new_size)) {
2714 DMERR("unable to shrink cache; cache block %llu is dirty",
2715 (unsigned long long) from_cblock(new_size));
2716 return false;
2717 }
2718 }
2719
2720 return true;
2721}
2722
2723static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size)
2724{
2725 int r;
2726
Vincent Pelletier08844802013-11-30 12:58:42 +01002727 r = dm_cache_resize(cache->cmd, new_size);
Joe Thornberf494a9c2013-10-31 13:55:49 -04002728 if (r) {
2729 DMERR("could not resize cache metadata");
2730 return r;
2731 }
2732
2733 cache->cache_size = new_size;
2734
2735 return 0;
2736}
2737
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002738static int cache_preresume(struct dm_target *ti)
2739{
2740 int r = 0;
2741 struct cache *cache = ti->private;
Joe Thornberf494a9c2013-10-31 13:55:49 -04002742 dm_cblock_t csize = get_cache_dev_size(cache);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002743
2744 /*
2745 * Check to see if the cache has resized.
2746 */
Joe Thornberf494a9c2013-10-31 13:55:49 -04002747 if (!cache->sized) {
2748 r = resize_cache_dev(cache, csize);
2749 if (r)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002750 return r;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002751
2752 cache->sized = true;
Joe Thornberf494a9c2013-10-31 13:55:49 -04002753
2754 } else if (csize != cache->cache_size) {
2755 if (!can_resize(cache, csize))
2756 return -EINVAL;
2757
2758 r = resize_cache_dev(cache, csize);
2759 if (r)
2760 return r;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002761 }
2762
2763 if (!cache->loaded_mappings) {
Mike Snitzerea2dd8c2013-03-20 17:21:28 +00002764 r = dm_cache_load_mappings(cache->cmd, cache->policy,
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002765 load_mapping, cache);
2766 if (r) {
2767 DMERR("could not load cache mappings");
2768 return r;
2769 }
2770
2771 cache->loaded_mappings = true;
2772 }
2773
2774 if (!cache->loaded_discards) {
2775 r = dm_cache_load_discards(cache->cmd, load_discard, cache);
2776 if (r) {
2777 DMERR("could not load origin discards");
2778 return r;
2779 }
2780
2781 cache->loaded_discards = true;
2782 }
2783
2784 return r;
2785}
2786
2787static void cache_resume(struct dm_target *ti)
2788{
2789 struct cache *cache = ti->private;
2790
2791 cache->need_tick_bio = true;
2792 do_waker(&cache->waker.work);
2793}
2794
2795/*
2796 * Status format:
2797 *
Mike Snitzer6a388612014-01-09 16:04:12 -05002798 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
2799 * <cache block size> <#used cache blocks>/<#total cache blocks>
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002800 * <#read hits> <#read misses> <#write hits> <#write misses>
Mike Snitzer6a388612014-01-09 16:04:12 -05002801 * <#demotions> <#promotions> <#dirty>
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002802 * <#features> <features>*
2803 * <#core args> <core args>
Mike Snitzer2e68c4e2014-01-15 21:06:55 -05002804 * <policy name> <#policy args> <policy args>*
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002805 */
2806static void cache_status(struct dm_target *ti, status_type_t type,
2807 unsigned status_flags, char *result, unsigned maxlen)
2808{
2809 int r = 0;
2810 unsigned i;
2811 ssize_t sz = 0;
2812 dm_block_t nr_free_blocks_metadata = 0;
2813 dm_block_t nr_blocks_metadata = 0;
2814 char buf[BDEVNAME_SIZE];
2815 struct cache *cache = ti->private;
2816 dm_cblock_t residency;
2817
2818 switch (type) {
2819 case STATUSTYPE_INFO:
2820 /* Commit to ensure statistics aren't out-of-date */
2821 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) {
2822 r = dm_cache_commit(cache->cmd, false);
2823 if (r)
2824 DMERR("could not commit metadata for accurate status");
2825 }
2826
2827 r = dm_cache_get_free_metadata_block_count(cache->cmd,
2828 &nr_free_blocks_metadata);
2829 if (r) {
2830 DMERR("could not get metadata free block count");
2831 goto err;
2832 }
2833
2834 r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata);
2835 if (r) {
2836 DMERR("could not get metadata device size");
2837 goto err;
2838 }
2839
2840 residency = policy_residency(cache->policy);
2841
Anssi Hannula44fa8162014-08-01 11:55:47 -04002842 DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %lu ",
Mike Snitzer895b47d2014-07-14 15:37:18 -04002843 (unsigned)DM_CACHE_METADATA_BLOCK_SIZE,
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002844 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2845 (unsigned long long)nr_blocks_metadata,
Mike Snitzer6a388612014-01-09 16:04:12 -05002846 cache->sectors_per_block,
2847 (unsigned long long) from_cblock(residency),
2848 (unsigned long long) from_cblock(cache->cache_size),
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002849 (unsigned) atomic_read(&cache->stats.read_hit),
2850 (unsigned) atomic_read(&cache->stats.read_miss),
2851 (unsigned) atomic_read(&cache->stats.write_hit),
2852 (unsigned) atomic_read(&cache->stats.write_miss),
2853 (unsigned) atomic_read(&cache->stats.demotion),
2854 (unsigned) atomic_read(&cache->stats.promotion),
Anssi Hannula44fa8162014-08-01 11:55:47 -04002855 (unsigned long) atomic_read(&cache->nr_dirty));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002856
Joe Thornber2ee57d52013-10-24 14:10:29 -04002857 if (writethrough_mode(&cache->features))
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002858 DMEMIT("1 writethrough ");
Joe Thornber2ee57d52013-10-24 14:10:29 -04002859
2860 else if (passthrough_mode(&cache->features))
2861 DMEMIT("1 passthrough ");
2862
2863 else if (writeback_mode(&cache->features))
2864 DMEMIT("1 writeback ");
2865
2866 else {
2867 DMERR("internal error: unknown io mode: %d", (int) cache->features.io_mode);
2868 goto err;
2869 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002870
2871 DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
Mike Snitzer2e68c4e2014-01-15 21:06:55 -05002872
2873 DMEMIT("%s ", dm_cache_policy_get_name(cache->policy));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002874 if (sz < maxlen) {
2875 r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz);
2876 if (r)
2877 DMERR("policy_emit_config_values returned %d", r);
2878 }
2879
2880 break;
2881
2882 case STATUSTYPE_TABLE:
2883 format_dev_t(buf, cache->metadata_dev->bdev->bd_dev);
2884 DMEMIT("%s ", buf);
2885 format_dev_t(buf, cache->cache_dev->bdev->bd_dev);
2886 DMEMIT("%s ", buf);
2887 format_dev_t(buf, cache->origin_dev->bdev->bd_dev);
2888 DMEMIT("%s", buf);
2889
2890 for (i = 0; i < cache->nr_ctr_args - 1; i++)
2891 DMEMIT(" %s", cache->ctr_args[i]);
2892 if (cache->nr_ctr_args)
2893 DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]);
2894 }
2895
2896 return;
2897
2898err:
2899 DMEMIT("Error");
2900}
2901
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002902/*
Joe Thornber65790ff2013-11-08 16:39:50 +00002903 * A cache block range can take two forms:
2904 *
2905 * i) A single cblock, eg. '3456'
2906 * ii) A begin and end cblock with dots between, eg. 123-234
2907 */
2908static int parse_cblock_range(struct cache *cache, const char *str,
2909 struct cblock_range *result)
2910{
2911 char dummy;
2912 uint64_t b, e;
2913 int r;
2914
2915 /*
2916 * Try and parse form (ii) first.
2917 */
2918 r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy);
2919 if (r < 0)
2920 return r;
2921
2922 if (r == 2) {
2923 result->begin = to_cblock(b);
2924 result->end = to_cblock(e);
2925 return 0;
2926 }
2927
2928 /*
2929 * That didn't work, try form (i).
2930 */
2931 r = sscanf(str, "%llu%c", &b, &dummy);
2932 if (r < 0)
2933 return r;
2934
2935 if (r == 1) {
2936 result->begin = to_cblock(b);
2937 result->end = to_cblock(from_cblock(result->begin) + 1u);
2938 return 0;
2939 }
2940
2941 DMERR("invalid cblock range '%s'", str);
2942 return -EINVAL;
2943}
2944
2945static int validate_cblock_range(struct cache *cache, struct cblock_range *range)
2946{
2947 uint64_t b = from_cblock(range->begin);
2948 uint64_t e = from_cblock(range->end);
2949 uint64_t n = from_cblock(cache->cache_size);
2950
2951 if (b >= n) {
2952 DMERR("begin cblock out of range: %llu >= %llu", b, n);
2953 return -EINVAL;
2954 }
2955
2956 if (e > n) {
2957 DMERR("end cblock out of range: %llu > %llu", e, n);
2958 return -EINVAL;
2959 }
2960
2961 if (b >= e) {
2962 DMERR("invalid cblock range: %llu >= %llu", b, e);
2963 return -EINVAL;
2964 }
2965
2966 return 0;
2967}
2968
2969static int request_invalidation(struct cache *cache, struct cblock_range *range)
2970{
2971 struct invalidation_request req;
2972
2973 INIT_LIST_HEAD(&req.list);
2974 req.cblocks = range;
2975 atomic_set(&req.complete, 0);
2976 req.err = 0;
2977 init_waitqueue_head(&req.result_wait);
2978
2979 spin_lock(&cache->invalidation_lock);
2980 list_add(&req.list, &cache->invalidation_requests);
2981 spin_unlock(&cache->invalidation_lock);
2982 wake_worker(cache);
2983
2984 wait_event(req.result_wait, atomic_read(&req.complete));
2985 return req.err;
2986}
2987
2988static int process_invalidate_cblocks_message(struct cache *cache, unsigned count,
2989 const char **cblock_ranges)
2990{
2991 int r = 0;
2992 unsigned i;
2993 struct cblock_range range;
2994
2995 if (!passthrough_mode(&cache->features)) {
2996 DMERR("cache has to be in passthrough mode for invalidation");
2997 return -EPERM;
2998 }
2999
3000 for (i = 0; i < count; i++) {
3001 r = parse_cblock_range(cache, cblock_ranges[i], &range);
3002 if (r)
3003 break;
3004
3005 r = validate_cblock_range(cache, &range);
3006 if (r)
3007 break;
3008
3009 /*
3010 * Pass begin and end origin blocks to the worker and wake it.
3011 */
3012 r = request_invalidation(cache, &range);
3013 if (r)
3014 break;
3015 }
3016
3017 return r;
3018}
3019
3020/*
3021 * Supports
3022 * "<key> <value>"
3023 * and
3024 * "invalidate_cblocks [(<begin>)|(<begin>-<end>)]*
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003025 *
3026 * The key migration_threshold is supported by the cache target core.
3027 */
3028static int cache_message(struct dm_target *ti, unsigned argc, char **argv)
3029{
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003030 struct cache *cache = ti->private;
3031
Joe Thornber65790ff2013-11-08 16:39:50 +00003032 if (!argc)
3033 return -EINVAL;
3034
Mike Snitzer7b6b2bc2013-11-12 12:17:43 -05003035 if (!strcasecmp(argv[0], "invalidate_cblocks"))
Joe Thornber65790ff2013-11-08 16:39:50 +00003036 return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1);
3037
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003038 if (argc != 2)
3039 return -EINVAL;
3040
Joe Thornber2f14f4b2013-05-10 14:37:21 +01003041 return set_config_value(cache, argv[0], argv[1]);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003042}
3043
3044static int cache_iterate_devices(struct dm_target *ti,
3045 iterate_devices_callout_fn fn, void *data)
3046{
3047 int r = 0;
3048 struct cache *cache = ti->private;
3049
3050 r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data);
3051 if (!r)
3052 r = fn(ti, cache->origin_dev, 0, ti->len, data);
3053
3054 return r;
3055}
3056
3057/*
3058 * We assume I/O is going to the origin (which is the volume
3059 * more likely to have restrictions e.g. by being striped).
3060 * (Looking up the exact location of the data would be expensive
3061 * and could always be out of date by the time the bio is submitted.)
3062 */
3063static int cache_bvec_merge(struct dm_target *ti,
3064 struct bvec_merge_data *bvm,
3065 struct bio_vec *biovec, int max_size)
3066{
3067 struct cache *cache = ti->private;
3068 struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev);
3069
3070 if (!q->merge_bvec_fn)
3071 return max_size;
3072
3073 bvm->bi_bdev = cache->origin_dev->bdev;
3074 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3075}
3076
3077static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
3078{
3079 /*
3080 * FIXME: these limits may be incompatible with the cache device
3081 */
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04003082 limits->max_discard_sectors = cache->sectors_per_block;
3083 limits->discard_granularity = cache->sectors_per_block << SECTOR_SHIFT;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003084}
3085
3086static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
3087{
3088 struct cache *cache = ti->private;
Mike Snitzerf6109372013-08-20 15:02:41 -04003089 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003090
Mike Snitzerf6109372013-08-20 15:02:41 -04003091 /*
3092 * If the system-determined stacked limits are compatible with the
3093 * cache's blocksize (io_opt is a factor) do not override them.
3094 */
3095 if (io_opt_sectors < cache->sectors_per_block ||
3096 do_div(io_opt_sectors, cache->sectors_per_block)) {
3097 blk_limits_io_min(limits, 0);
3098 blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
3099 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003100 set_discard_limits(cache, limits);
3101}
3102
3103/*----------------------------------------------------------------*/
3104
3105static struct target_type cache_target = {
3106 .name = "cache",
Joe Thornber8c081b52014-05-13 16:18:38 +01003107 .version = {1, 5, 0},
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003108 .module = THIS_MODULE,
3109 .ctr = cache_ctr,
3110 .dtr = cache_dtr,
3111 .map = cache_map,
3112 .end_io = cache_end_io,
3113 .postsuspend = cache_postsuspend,
3114 .preresume = cache_preresume,
3115 .resume = cache_resume,
3116 .status = cache_status,
3117 .message = cache_message,
3118 .iterate_devices = cache_iterate_devices,
3119 .merge = cache_bvec_merge,
3120 .io_hints = cache_io_hints,
3121};
3122
3123static int __init dm_cache_init(void)
3124{
3125 int r;
3126
3127 r = dm_register_target(&cache_target);
3128 if (r) {
3129 DMERR("cache target registration failed: %d", r);
3130 return r;
3131 }
3132
3133 migration_cache = KMEM_CACHE(dm_cache_migration, 0);
3134 if (!migration_cache) {
3135 dm_unregister_target(&cache_target);
3136 return -ENOMEM;
3137 }
3138
3139 return 0;
3140}
3141
3142static void __exit dm_cache_exit(void)
3143{
3144 dm_unregister_target(&cache_target);
3145 kmem_cache_destroy(migration_cache);
3146}
3147
3148module_init(dm_cache_init);
3149module_exit(dm_cache_exit);
3150
3151MODULE_DESCRIPTION(DM_NAME " cache target");
3152MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
3153MODULE_LICENSE("GPL");