blob: 1bf4a71919ec73957a00550dec49b3a3b3a1292c [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 */
234 dm_cblock_t nr_dirty;
235 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)) {
495 cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) + 1);
496 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);
504 cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) - 1);
505 if (!from_cblock(cache->nr_dirty))
506 dm_table_event(cache->ti->table);
507 }
508}
509
510/*----------------------------------------------------------------*/
Joe Thornberaeed1422013-05-10 14:37:18 +0100511
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000512static bool block_size_is_power_of_two(struct cache *cache)
513{
514 return cache->sectors_per_block_shift >= 0;
515}
516
Mikulas Patocka43aeaa22013-07-10 23:41:17 +0100517/* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */
518#if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6
519__always_inline
520#endif
Joe Thornber414dd672013-03-20 17:21:25 +0000521static dm_block_t block_div(dm_block_t b, uint32_t n)
522{
523 do_div(b, n);
524
525 return b;
526}
527
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400528static void set_discard(struct cache *cache, dm_oblock_t b)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000529{
530 unsigned long flags;
531
532 atomic_inc(&cache->stats.discard_count);
533
534 spin_lock_irqsave(&cache->lock, flags);
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400535 set_bit(from_oblock(b), cache->discard_bitset);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000536 spin_unlock_irqrestore(&cache->lock, flags);
537}
538
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400539static void clear_discard(struct cache *cache, dm_oblock_t b)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000540{
541 unsigned long flags;
542
543 spin_lock_irqsave(&cache->lock, flags);
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400544 clear_bit(from_oblock(b), cache->discard_bitset);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000545 spin_unlock_irqrestore(&cache->lock, flags);
546}
547
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400548static bool is_discarded(struct cache *cache, dm_oblock_t b)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000549{
550 int r;
551 unsigned long flags;
552
553 spin_lock_irqsave(&cache->lock, flags);
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400554 r = test_bit(from_oblock(b), cache->discard_bitset);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000555 spin_unlock_irqrestore(&cache->lock, flags);
556
557 return r;
558}
559
560static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b)
561{
562 int r;
563 unsigned long flags;
564
565 spin_lock_irqsave(&cache->lock, flags);
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400566 r = test_bit(from_oblock(b), cache->discard_bitset);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000567 spin_unlock_irqrestore(&cache->lock, flags);
568
569 return r;
570}
571
572/*----------------------------------------------------------------*/
573
574static void load_stats(struct cache *cache)
575{
576 struct dm_cache_statistics stats;
577
578 dm_cache_metadata_get_stats(cache->cmd, &stats);
579 atomic_set(&cache->stats.read_hit, stats.read_hits);
580 atomic_set(&cache->stats.read_miss, stats.read_misses);
581 atomic_set(&cache->stats.write_hit, stats.write_hits);
582 atomic_set(&cache->stats.write_miss, stats.write_misses);
583}
584
585static void save_stats(struct cache *cache)
586{
587 struct dm_cache_statistics stats;
588
589 stats.read_hits = atomic_read(&cache->stats.read_hit);
590 stats.read_misses = atomic_read(&cache->stats.read_miss);
591 stats.write_hits = atomic_read(&cache->stats.write_hit);
592 stats.write_misses = atomic_read(&cache->stats.write_miss);
593
594 dm_cache_metadata_set_stats(cache->cmd, &stats);
595}
596
597/*----------------------------------------------------------------
598 * Per bio data
599 *--------------------------------------------------------------*/
Mike Snitzer19b00922013-04-05 15:36:34 +0100600
601/*
602 * If using writeback, leave out struct per_bio_data's writethrough fields.
603 */
604#define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache))
605#define PB_DATA_SIZE_WT (sizeof(struct per_bio_data))
606
Joe Thornber2ee57d52013-10-24 14:10:29 -0400607static bool writethrough_mode(struct cache_features *f)
608{
609 return f->io_mode == CM_IO_WRITETHROUGH;
610}
611
612static bool writeback_mode(struct cache_features *f)
613{
614 return f->io_mode == CM_IO_WRITEBACK;
615}
616
617static bool passthrough_mode(struct cache_features *f)
618{
619 return f->io_mode == CM_IO_PASSTHROUGH;
620}
621
Mike Snitzer19b00922013-04-05 15:36:34 +0100622static size_t get_per_bio_data_size(struct cache *cache)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000623{
Joe Thornber2ee57d52013-10-24 14:10:29 -0400624 return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB;
Mike Snitzer19b00922013-04-05 15:36:34 +0100625}
626
627static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size)
628{
629 struct per_bio_data *pb = dm_per_bio_data(bio, data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000630 BUG_ON(!pb);
631 return pb;
632}
633
Mike Snitzer19b00922013-04-05 15:36:34 +0100634static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000635{
Mike Snitzer19b00922013-04-05 15:36:34 +0100636 struct per_bio_data *pb = get_per_bio_data(bio, data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000637
638 pb->tick = false;
639 pb->req_nr = dm_bio_get_target_bio_nr(bio);
640 pb->all_io_entry = NULL;
641
642 return pb;
643}
644
645/*----------------------------------------------------------------
646 * Remapping
647 *--------------------------------------------------------------*/
648static void remap_to_origin(struct cache *cache, struct bio *bio)
649{
650 bio->bi_bdev = cache->origin_dev->bdev;
651}
652
653static void remap_to_cache(struct cache *cache, struct bio *bio,
654 dm_cblock_t cblock)
655{
Kent Overstreet4f024f32013-10-11 15:44:27 -0700656 sector_t bi_sector = bio->bi_iter.bi_sector;
Heinz Mauelshagene0d849f2014-02-27 22:46:48 +0100657 sector_t block = from_cblock(cblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000658
659 bio->bi_bdev = cache->cache_dev->bdev;
660 if (!block_size_is_power_of_two(cache))
Kent Overstreet4f024f32013-10-11 15:44:27 -0700661 bio->bi_iter.bi_sector =
Heinz Mauelshagene0d849f2014-02-27 22:46:48 +0100662 (block * cache->sectors_per_block) +
Kent Overstreet4f024f32013-10-11 15:44:27 -0700663 sector_div(bi_sector, cache->sectors_per_block);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000664 else
Kent Overstreet4f024f32013-10-11 15:44:27 -0700665 bio->bi_iter.bi_sector =
Heinz Mauelshagene0d849f2014-02-27 22:46:48 +0100666 (block << cache->sectors_per_block_shift) |
Kent Overstreet4f024f32013-10-11 15:44:27 -0700667 (bi_sector & (cache->sectors_per_block - 1));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000668}
669
670static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)
671{
672 unsigned long flags;
Mike Snitzer19b00922013-04-05 15:36:34 +0100673 size_t pb_data_size = get_per_bio_data_size(cache);
674 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000675
676 spin_lock_irqsave(&cache->lock, flags);
677 if (cache->need_tick_bio &&
678 !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) {
679 pb->tick = true;
680 cache->need_tick_bio = false;
681 }
682 spin_unlock_irqrestore(&cache->lock, flags);
683}
684
685static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio,
686 dm_oblock_t oblock)
687{
688 check_if_tick_bio_needed(cache, bio);
689 remap_to_origin(cache, bio);
690 if (bio_data_dir(bio) == WRITE)
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400691 clear_discard(cache, oblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000692}
693
694static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
695 dm_oblock_t oblock, dm_cblock_t cblock)
696{
Joe Thornberf8e5f012013-10-21 12:51:45 +0100697 check_if_tick_bio_needed(cache, bio);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000698 remap_to_cache(cache, bio, cblock);
699 if (bio_data_dir(bio) == WRITE) {
700 set_dirty(cache, oblock, cblock);
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -0400701 clear_discard(cache, oblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000702 }
703}
704
705static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio)
706{
Kent Overstreet4f024f32013-10-11 15:44:27 -0700707 sector_t block_nr = bio->bi_iter.bi_sector;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000708
709 if (!block_size_is_power_of_two(cache))
710 (void) sector_div(block_nr, cache->sectors_per_block);
711 else
712 block_nr >>= cache->sectors_per_block_shift;
713
714 return to_oblock(block_nr);
715}
716
717static int bio_triggers_commit(struct cache *cache, struct bio *bio)
718{
719 return bio->bi_rw & (REQ_FLUSH | REQ_FUA);
720}
721
722static void issue(struct cache *cache, struct bio *bio)
723{
724 unsigned long flags;
725
726 if (!bio_triggers_commit(cache, bio)) {
727 generic_make_request(bio);
728 return;
729 }
730
731 /*
732 * Batch together any bios that trigger commits and then issue a
733 * single commit for them in do_worker().
734 */
735 spin_lock_irqsave(&cache->lock, flags);
736 cache->commit_requested = true;
737 bio_list_add(&cache->deferred_flush_bios, bio);
738 spin_unlock_irqrestore(&cache->lock, flags);
739}
740
Joe Thornbere2e74d62013-03-20 17:21:27 +0000741static void defer_writethrough_bio(struct cache *cache, struct bio *bio)
742{
743 unsigned long flags;
744
745 spin_lock_irqsave(&cache->lock, flags);
746 bio_list_add(&cache->deferred_writethrough_bios, bio);
747 spin_unlock_irqrestore(&cache->lock, flags);
748
749 wake_worker(cache);
750}
751
752static void writethrough_endio(struct bio *bio, int err)
753{
Mike Snitzer19b00922013-04-05 15:36:34 +0100754 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
Joe Thornberc9d28d52013-10-31 13:55:48 -0400755
756 dm_unhook_bio(&pb->hook_info, bio);
Joe Thornbere2e74d62013-03-20 17:21:27 +0000757
758 if (err) {
759 bio_endio(bio, err);
760 return;
761 }
762
Darrick J. Wongb844fe62013-04-05 15:36:32 +0100763 dm_bio_restore(&pb->bio_details, bio);
Joe Thornbere2e74d62013-03-20 17:21:27 +0000764 remap_to_cache(pb->cache, bio, pb->cblock);
765
766 /*
767 * We can't issue this bio directly, since we're in interrupt
Joe Thornberaeed1422013-05-10 14:37:18 +0100768 * context. So it gets put on a bio list for processing by the
Joe Thornbere2e74d62013-03-20 17:21:27 +0000769 * worker thread.
770 */
771 defer_writethrough_bio(pb->cache, bio);
772}
773
774/*
775 * When running in writethrough mode we need to send writes to clean blocks
776 * to both the cache and origin devices. In future we'd like to clone the
777 * bio and send them in parallel, but for now we're doing them in
778 * series as this is easier.
779 */
780static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio,
781 dm_oblock_t oblock, dm_cblock_t cblock)
782{
Mike Snitzer19b00922013-04-05 15:36:34 +0100783 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
Joe Thornbere2e74d62013-03-20 17:21:27 +0000784
785 pb->cache = cache;
786 pb->cblock = cblock;
Joe Thornberc9d28d52013-10-31 13:55:48 -0400787 dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL);
Darrick J. Wongb844fe62013-04-05 15:36:32 +0100788 dm_bio_record(&pb->bio_details, bio);
Joe Thornbere2e74d62013-03-20 17:21:27 +0000789
790 remap_to_origin_clear_discard(pb->cache, bio, oblock);
791}
792
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000793/*----------------------------------------------------------------
794 * Migration processing
795 *
796 * Migration covers moving data from the origin device to the cache, or
797 * vice versa.
798 *--------------------------------------------------------------*/
799static void free_migration(struct dm_cache_migration *mg)
800{
801 mempool_free(mg, mg->cache->migration_pool);
802}
803
804static void inc_nr_migrations(struct cache *cache)
805{
806 atomic_inc(&cache->nr_migrations);
807}
808
809static void dec_nr_migrations(struct cache *cache)
810{
811 atomic_dec(&cache->nr_migrations);
812
813 /*
814 * Wake the worker in case we're suspending the target.
815 */
816 wake_up(&cache->migration_wait);
817}
818
819static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
820 bool holder)
821{
822 (holder ? dm_cell_release : dm_cell_release_no_holder)
823 (cache->prison, cell, &cache->deferred_bios);
824 free_prison_cell(cache, cell);
825}
826
827static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
828 bool holder)
829{
830 unsigned long flags;
831
832 spin_lock_irqsave(&cache->lock, flags);
833 __cell_defer(cache, cell, holder);
834 spin_unlock_irqrestore(&cache->lock, flags);
835
836 wake_worker(cache);
837}
838
839static void cleanup_migration(struct dm_cache_migration *mg)
840{
Joe Thornber66cb1912013-10-30 17:11:58 +0000841 struct cache *cache = mg->cache;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000842 free_migration(mg);
Joe Thornber66cb1912013-10-30 17:11:58 +0000843 dec_nr_migrations(cache);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000844}
845
846static void migration_failure(struct dm_cache_migration *mg)
847{
848 struct cache *cache = mg->cache;
849
850 if (mg->writeback) {
851 DMWARN_LIMIT("writeback failed; couldn't copy block");
852 set_dirty(cache, mg->old_oblock, mg->cblock);
853 cell_defer(cache, mg->old_ocell, false);
854
855 } else if (mg->demote) {
856 DMWARN_LIMIT("demotion failed; couldn't copy block");
857 policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock);
858
Heinz Mauelshagen80f659f2013-10-14 17:10:47 +0200859 cell_defer(cache, mg->old_ocell, mg->promote ? false : true);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000860 if (mg->promote)
Heinz Mauelshagen80f659f2013-10-14 17:10:47 +0200861 cell_defer(cache, mg->new_ocell, true);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000862 } else {
863 DMWARN_LIMIT("promotion failed; couldn't copy block");
864 policy_remove_mapping(cache->policy, mg->new_oblock);
Heinz Mauelshagen80f659f2013-10-14 17:10:47 +0200865 cell_defer(cache, mg->new_ocell, true);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000866 }
867
868 cleanup_migration(mg);
869}
870
871static void migration_success_pre_commit(struct dm_cache_migration *mg)
872{
873 unsigned long flags;
874 struct cache *cache = mg->cache;
875
876 if (mg->writeback) {
877 cell_defer(cache, mg->old_ocell, false);
878 clear_dirty(cache, mg->old_oblock, mg->cblock);
879 cleanup_migration(mg);
880 return;
881
882 } else if (mg->demote) {
883 if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) {
884 DMWARN_LIMIT("demotion failed; couldn't update on disk metadata");
885 policy_force_mapping(cache->policy, mg->new_oblock,
886 mg->old_oblock);
887 if (mg->promote)
888 cell_defer(cache, mg->new_ocell, true);
889 cleanup_migration(mg);
890 return;
891 }
892 } else {
893 if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) {
894 DMWARN_LIMIT("promotion failed; couldn't update on disk metadata");
895 policy_remove_mapping(cache->policy, mg->new_oblock);
896 cleanup_migration(mg);
897 return;
898 }
899 }
900
901 spin_lock_irqsave(&cache->lock, flags);
902 list_add_tail(&mg->list, &cache->need_commit_migrations);
903 cache->commit_requested = true;
904 spin_unlock_irqrestore(&cache->lock, flags);
905}
906
907static void migration_success_post_commit(struct dm_cache_migration *mg)
908{
909 unsigned long flags;
910 struct cache *cache = mg->cache;
911
912 if (mg->writeback) {
913 DMWARN("writeback unexpectedly triggered commit");
914 return;
915
916 } else if (mg->demote) {
Heinz Mauelshagen80f659f2013-10-14 17:10:47 +0200917 cell_defer(cache, mg->old_ocell, mg->promote ? false : true);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000918
919 if (mg->promote) {
920 mg->demote = false;
921
922 spin_lock_irqsave(&cache->lock, flags);
923 list_add_tail(&mg->list, &cache->quiesced_migrations);
924 spin_unlock_irqrestore(&cache->lock, flags);
925
Joe Thornber65790ff2013-11-08 16:39:50 +0000926 } else {
927 if (mg->invalidate)
928 policy_remove_mapping(cache->policy, mg->old_oblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000929 cleanup_migration(mg);
Joe Thornber65790ff2013-11-08 16:39:50 +0000930 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000931
932 } else {
Joe Thornberc9d28d52013-10-31 13:55:48 -0400933 if (mg->requeue_holder)
934 cell_defer(cache, mg->new_ocell, true);
935 else {
936 bio_endio(mg->new_ocell->holder, 0);
937 cell_defer(cache, mg->new_ocell, false);
938 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000939 clear_dirty(cache, mg->new_oblock, mg->cblock);
940 cleanup_migration(mg);
941 }
942}
943
944static void copy_complete(int read_err, unsigned long write_err, void *context)
945{
946 unsigned long flags;
947 struct dm_cache_migration *mg = (struct dm_cache_migration *) context;
948 struct cache *cache = mg->cache;
949
950 if (read_err || write_err)
951 mg->err = true;
952
953 spin_lock_irqsave(&cache->lock, flags);
954 list_add_tail(&mg->list, &cache->completed_migrations);
955 spin_unlock_irqrestore(&cache->lock, flags);
956
957 wake_worker(cache);
958}
959
960static void issue_copy_real(struct dm_cache_migration *mg)
961{
962 int r;
963 struct dm_io_region o_region, c_region;
964 struct cache *cache = mg->cache;
Heinz Mauelshagen8b9d9662014-03-12 00:40:05 +0100965 sector_t cblock = from_cblock(mg->cblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000966
967 o_region.bdev = cache->origin_dev->bdev;
968 o_region.count = cache->sectors_per_block;
969
970 c_region.bdev = cache->cache_dev->bdev;
Heinz Mauelshagen8b9d9662014-03-12 00:40:05 +0100971 c_region.sector = cblock * cache->sectors_per_block;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000972 c_region.count = cache->sectors_per_block;
973
974 if (mg->writeback || mg->demote) {
975 /* demote */
976 o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block;
977 r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg);
978 } else {
979 /* promote */
980 o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block;
981 r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg);
982 }
983
Heinz Mauelshagen2c2263c2013-10-14 17:14:45 +0200984 if (r < 0) {
985 DMERR_LIMIT("issuing migration failed");
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000986 migration_failure(mg);
Heinz Mauelshagen2c2263c2013-10-14 17:14:45 +0200987 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +0000988}
989
Joe Thornberc9d28d52013-10-31 13:55:48 -0400990static void overwrite_endio(struct bio *bio, int err)
991{
992 struct dm_cache_migration *mg = bio->bi_private;
993 struct cache *cache = mg->cache;
994 size_t pb_data_size = get_per_bio_data_size(cache);
995 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
996 unsigned long flags;
997
Mike Snitzer80ae49a2014-01-31 14:30:37 -0500998 dm_unhook_bio(&pb->hook_info, bio);
999
Joe Thornberc9d28d52013-10-31 13:55:48 -04001000 if (err)
1001 mg->err = true;
1002
Mike Snitzer80ae49a2014-01-31 14:30:37 -05001003 mg->requeue_holder = false;
1004
Joe Thornberc9d28d52013-10-31 13:55:48 -04001005 spin_lock_irqsave(&cache->lock, flags);
1006 list_add_tail(&mg->list, &cache->completed_migrations);
Joe Thornberc9d28d52013-10-31 13:55:48 -04001007 spin_unlock_irqrestore(&cache->lock, flags);
1008
1009 wake_worker(cache);
1010}
1011
1012static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio)
1013{
1014 size_t pb_data_size = get_per_bio_data_size(mg->cache);
1015 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1016
1017 dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg);
1018 remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock);
1019 generic_make_request(bio);
1020}
1021
1022static bool bio_writes_complete_block(struct cache *cache, struct bio *bio)
1023{
1024 return (bio_data_dir(bio) == WRITE) &&
Kent Overstreet4f024f32013-10-11 15:44:27 -07001025 (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT));
Joe Thornberc9d28d52013-10-31 13:55:48 -04001026}
1027
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001028static void avoid_copy(struct dm_cache_migration *mg)
1029{
1030 atomic_inc(&mg->cache->stats.copies_avoided);
1031 migration_success_pre_commit(mg);
1032}
1033
1034static void issue_copy(struct dm_cache_migration *mg)
1035{
1036 bool avoid;
1037 struct cache *cache = mg->cache;
1038
1039 if (mg->writeback || mg->demote)
1040 avoid = !is_dirty(cache, mg->cblock) ||
1041 is_discarded_oblock(cache, mg->old_oblock);
Joe Thornberc9d28d52013-10-31 13:55:48 -04001042 else {
1043 struct bio *bio = mg->new_ocell->holder;
1044
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001045 avoid = is_discarded_oblock(cache, mg->new_oblock);
1046
Joe Thornberc9d28d52013-10-31 13:55:48 -04001047 if (!avoid && bio_writes_complete_block(cache, bio)) {
1048 issue_overwrite(mg, bio);
1049 return;
1050 }
1051 }
1052
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001053 avoid ? avoid_copy(mg) : issue_copy_real(mg);
1054}
1055
1056static void complete_migration(struct dm_cache_migration *mg)
1057{
1058 if (mg->err)
1059 migration_failure(mg);
1060 else
1061 migration_success_pre_commit(mg);
1062}
1063
1064static void process_migrations(struct cache *cache, struct list_head *head,
1065 void (*fn)(struct dm_cache_migration *))
1066{
1067 unsigned long flags;
1068 struct list_head list;
1069 struct dm_cache_migration *mg, *tmp;
1070
1071 INIT_LIST_HEAD(&list);
1072 spin_lock_irqsave(&cache->lock, flags);
1073 list_splice_init(head, &list);
1074 spin_unlock_irqrestore(&cache->lock, flags);
1075
1076 list_for_each_entry_safe(mg, tmp, &list, list)
1077 fn(mg);
1078}
1079
1080static void __queue_quiesced_migration(struct dm_cache_migration *mg)
1081{
1082 list_add_tail(&mg->list, &mg->cache->quiesced_migrations);
1083}
1084
1085static void queue_quiesced_migration(struct dm_cache_migration *mg)
1086{
1087 unsigned long flags;
1088 struct cache *cache = mg->cache;
1089
1090 spin_lock_irqsave(&cache->lock, flags);
1091 __queue_quiesced_migration(mg);
1092 spin_unlock_irqrestore(&cache->lock, flags);
1093
1094 wake_worker(cache);
1095}
1096
1097static void queue_quiesced_migrations(struct cache *cache, struct list_head *work)
1098{
1099 unsigned long flags;
1100 struct dm_cache_migration *mg, *tmp;
1101
1102 spin_lock_irqsave(&cache->lock, flags);
1103 list_for_each_entry_safe(mg, tmp, work, list)
1104 __queue_quiesced_migration(mg);
1105 spin_unlock_irqrestore(&cache->lock, flags);
1106
1107 wake_worker(cache);
1108}
1109
1110static void check_for_quiesced_migrations(struct cache *cache,
1111 struct per_bio_data *pb)
1112{
1113 struct list_head work;
1114
1115 if (!pb->all_io_entry)
1116 return;
1117
1118 INIT_LIST_HEAD(&work);
1119 if (pb->all_io_entry)
1120 dm_deferred_entry_dec(pb->all_io_entry, &work);
1121
1122 if (!list_empty(&work))
1123 queue_quiesced_migrations(cache, &work);
1124}
1125
1126static void quiesce_migration(struct dm_cache_migration *mg)
1127{
1128 if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list))
1129 queue_quiesced_migration(mg);
1130}
1131
1132static void promote(struct cache *cache, struct prealloc *structs,
1133 dm_oblock_t oblock, dm_cblock_t cblock,
1134 struct dm_bio_prison_cell *cell)
1135{
1136 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1137
1138 mg->err = false;
1139 mg->writeback = false;
1140 mg->demote = false;
1141 mg->promote = true;
Joe Thornberc9d28d52013-10-31 13:55:48 -04001142 mg->requeue_holder = true;
Joe Thornber65790ff2013-11-08 16:39:50 +00001143 mg->invalidate = false;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001144 mg->cache = cache;
1145 mg->new_oblock = oblock;
1146 mg->cblock = cblock;
1147 mg->old_ocell = NULL;
1148 mg->new_ocell = cell;
1149 mg->start_jiffies = jiffies;
1150
1151 inc_nr_migrations(cache);
1152 quiesce_migration(mg);
1153}
1154
1155static void writeback(struct cache *cache, struct prealloc *structs,
1156 dm_oblock_t oblock, dm_cblock_t cblock,
1157 struct dm_bio_prison_cell *cell)
1158{
1159 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1160
1161 mg->err = false;
1162 mg->writeback = true;
1163 mg->demote = false;
1164 mg->promote = false;
Joe Thornberc9d28d52013-10-31 13:55:48 -04001165 mg->requeue_holder = true;
Joe Thornber65790ff2013-11-08 16:39:50 +00001166 mg->invalidate = false;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001167 mg->cache = cache;
1168 mg->old_oblock = oblock;
1169 mg->cblock = cblock;
1170 mg->old_ocell = cell;
1171 mg->new_ocell = NULL;
1172 mg->start_jiffies = jiffies;
1173
1174 inc_nr_migrations(cache);
1175 quiesce_migration(mg);
1176}
1177
1178static void demote_then_promote(struct cache *cache, struct prealloc *structs,
1179 dm_oblock_t old_oblock, dm_oblock_t new_oblock,
1180 dm_cblock_t cblock,
1181 struct dm_bio_prison_cell *old_ocell,
1182 struct dm_bio_prison_cell *new_ocell)
1183{
1184 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1185
1186 mg->err = false;
1187 mg->writeback = false;
1188 mg->demote = true;
1189 mg->promote = true;
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 = old_oblock;
1194 mg->new_oblock = new_oblock;
1195 mg->cblock = cblock;
1196 mg->old_ocell = old_ocell;
1197 mg->new_ocell = new_ocell;
1198 mg->start_jiffies = jiffies;
1199
1200 inc_nr_migrations(cache);
1201 quiesce_migration(mg);
1202}
1203
Joe Thornber2ee57d52013-10-24 14:10:29 -04001204/*
1205 * Invalidate a cache entry. No writeback occurs; any changes in the cache
1206 * block are thrown away.
1207 */
1208static void invalidate(struct cache *cache, struct prealloc *structs,
1209 dm_oblock_t oblock, dm_cblock_t cblock,
1210 struct dm_bio_prison_cell *cell)
1211{
1212 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1213
1214 mg->err = false;
1215 mg->writeback = false;
1216 mg->demote = true;
1217 mg->promote = false;
1218 mg->requeue_holder = true;
Joe Thornber65790ff2013-11-08 16:39:50 +00001219 mg->invalidate = true;
Joe Thornber2ee57d52013-10-24 14:10:29 -04001220 mg->cache = cache;
1221 mg->old_oblock = oblock;
1222 mg->cblock = cblock;
1223 mg->old_ocell = cell;
1224 mg->new_ocell = NULL;
1225 mg->start_jiffies = jiffies;
1226
1227 inc_nr_migrations(cache);
1228 quiesce_migration(mg);
1229}
1230
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001231/*----------------------------------------------------------------
1232 * bio processing
1233 *--------------------------------------------------------------*/
1234static void defer_bio(struct cache *cache, struct bio *bio)
1235{
1236 unsigned long flags;
1237
1238 spin_lock_irqsave(&cache->lock, flags);
1239 bio_list_add(&cache->deferred_bios, bio);
1240 spin_unlock_irqrestore(&cache->lock, flags);
1241
1242 wake_worker(cache);
1243}
1244
1245static void process_flush_bio(struct cache *cache, struct bio *bio)
1246{
Mike Snitzer19b00922013-04-05 15:36:34 +01001247 size_t pb_data_size = get_per_bio_data_size(cache);
1248 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001249
Kent Overstreet4f024f32013-10-11 15:44:27 -07001250 BUG_ON(bio->bi_iter.bi_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001251 if (!pb->req_nr)
1252 remap_to_origin(cache, bio);
1253 else
1254 remap_to_cache(cache, bio, 0);
1255
1256 issue(cache, bio);
1257}
1258
1259/*
1260 * People generally discard large parts of a device, eg, the whole device
1261 * when formatting. Splitting these large discards up into cache block
1262 * sized ios and then quiescing (always neccessary for discard) takes too
1263 * long.
1264 *
1265 * We keep it simple, and allow any size of discard to come in, and just
1266 * mark off blocks on the discard bitset. No passdown occurs!
1267 *
1268 * To implement passdown we need to change the bio_prison such that a cell
1269 * can have a key that spans many blocks.
1270 */
1271static void process_discard_bio(struct cache *cache, struct bio *bio)
1272{
Kent Overstreet4f024f32013-10-11 15:44:27 -07001273 dm_block_t start_block = dm_sector_div_up(bio->bi_iter.bi_sector,
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04001274 cache->sectors_per_block);
Kent Overstreet4f024f32013-10-11 15:44:27 -07001275 dm_block_t end_block = bio_end_sector(bio);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001276 dm_block_t b;
1277
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04001278 end_block = block_div(end_block, cache->sectors_per_block);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001279
1280 for (b = start_block; b < end_block; b++)
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04001281 set_discard(cache, to_oblock(b));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001282
1283 bio_endio(bio, 0);
1284}
1285
1286static bool spare_migration_bandwidth(struct cache *cache)
1287{
1288 sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) *
1289 cache->sectors_per_block;
1290 return current_volume < cache->migration_threshold;
1291}
1292
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001293static void inc_hit_counter(struct cache *cache, struct bio *bio)
1294{
1295 atomic_inc(bio_data_dir(bio) == READ ?
1296 &cache->stats.read_hit : &cache->stats.write_hit);
1297}
1298
1299static void inc_miss_counter(struct cache *cache, struct bio *bio)
1300{
1301 atomic_inc(bio_data_dir(bio) == READ ?
1302 &cache->stats.read_miss : &cache->stats.write_miss);
1303}
1304
Joe Thornber2ee57d52013-10-24 14:10:29 -04001305static void issue_cache_bio(struct cache *cache, struct bio *bio,
1306 struct per_bio_data *pb,
1307 dm_oblock_t oblock, dm_cblock_t cblock)
1308{
1309 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
1310 remap_to_cache_dirty(cache, bio, oblock, cblock);
1311 issue(cache, bio);
1312}
1313
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001314static void process_bio(struct cache *cache, struct prealloc *structs,
1315 struct bio *bio)
1316{
1317 int r;
1318 bool release_cell = true;
1319 dm_oblock_t block = get_bio_block(cache, bio);
1320 struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell;
1321 struct policy_result lookup_result;
Mike Snitzer19b00922013-04-05 15:36:34 +01001322 size_t pb_data_size = get_per_bio_data_size(cache);
1323 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001324 bool discarded_block = is_discarded_oblock(cache, block);
Joe Thornber2ee57d52013-10-24 14:10:29 -04001325 bool passthrough = passthrough_mode(&cache->features);
1326 bool can_migrate = !passthrough && (discarded_block || spare_migration_bandwidth(cache));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001327
1328 /*
1329 * Check to see if that block is currently migrating.
1330 */
1331 cell_prealloc = prealloc_get_cell(structs);
1332 r = bio_detain(cache, block, bio, cell_prealloc,
1333 (cell_free_fn) prealloc_put_cell,
1334 structs, &new_ocell);
1335 if (r > 0)
1336 return;
1337
1338 r = policy_map(cache->policy, block, true, can_migrate, discarded_block,
1339 bio, &lookup_result);
1340
1341 if (r == -EWOULDBLOCK)
1342 /* migration has been denied */
1343 lookup_result.op = POLICY_MISS;
1344
1345 switch (lookup_result.op) {
1346 case POLICY_HIT:
Joe Thornber2ee57d52013-10-24 14:10:29 -04001347 if (passthrough) {
1348 inc_miss_counter(cache, bio);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001349
Joe Thornber2ee57d52013-10-24 14:10:29 -04001350 /*
1351 * Passthrough always maps to the origin,
1352 * invalidating any cache blocks that are written
1353 * to.
1354 */
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001355
Joe Thornber2ee57d52013-10-24 14:10:29 -04001356 if (bio_data_dir(bio) == WRITE) {
1357 atomic_inc(&cache->stats.demotion);
1358 invalidate(cache, structs, block, lookup_result.cblock, new_ocell);
1359 release_cell = false;
1360
1361 } else {
1362 /* FIXME: factor out issue_origin() */
1363 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
1364 remap_to_origin_clear_discard(cache, bio, block);
1365 issue(cache, bio);
1366 }
1367 } else {
1368 inc_hit_counter(cache, bio);
1369
1370 if (bio_data_dir(bio) == WRITE &&
1371 writethrough_mode(&cache->features) &&
1372 !is_dirty(cache, lookup_result.cblock)) {
1373 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
1374 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
1375 issue(cache, bio);
1376 } else
1377 issue_cache_bio(cache, bio, pb, block, lookup_result.cblock);
1378 }
1379
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001380 break;
1381
1382 case POLICY_MISS:
1383 inc_miss_counter(cache, bio);
1384 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
Joe Thornbere2e74d62013-03-20 17:21:27 +00001385 remap_to_origin_clear_discard(cache, bio, block);
1386 issue(cache, bio);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001387 break;
1388
1389 case POLICY_NEW:
1390 atomic_inc(&cache->stats.promotion);
1391 promote(cache, structs, block, lookup_result.cblock, new_ocell);
1392 release_cell = false;
1393 break;
1394
1395 case POLICY_REPLACE:
1396 cell_prealloc = prealloc_get_cell(structs);
1397 r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc,
1398 (cell_free_fn) prealloc_put_cell,
1399 structs, &old_ocell);
1400 if (r > 0) {
1401 /*
1402 * We have to be careful to avoid lock inversion of
1403 * the cells. So we back off, and wait for the
1404 * old_ocell to become free.
1405 */
1406 policy_force_mapping(cache->policy, block,
1407 lookup_result.old_oblock);
1408 atomic_inc(&cache->stats.cache_cell_clash);
1409 break;
1410 }
1411 atomic_inc(&cache->stats.demotion);
1412 atomic_inc(&cache->stats.promotion);
1413
1414 demote_then_promote(cache, structs, lookup_result.old_oblock,
1415 block, lookup_result.cblock,
1416 old_ocell, new_ocell);
1417 release_cell = false;
1418 break;
1419
1420 default:
1421 DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__,
1422 (unsigned) lookup_result.op);
1423 bio_io_error(bio);
1424 }
1425
1426 if (release_cell)
1427 cell_defer(cache, new_ocell, false);
1428}
1429
1430static int need_commit_due_to_time(struct cache *cache)
1431{
1432 return jiffies < cache->last_commit_jiffies ||
1433 jiffies > cache->last_commit_jiffies + COMMIT_PERIOD;
1434}
1435
1436static int commit_if_needed(struct cache *cache)
1437{
Heinz Mauelshagenffcbcb62013-10-14 17:24:43 +02001438 int r = 0;
1439
1440 if ((cache->commit_requested || need_commit_due_to_time(cache)) &&
1441 dm_cache_changed_this_transaction(cache->cmd)) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001442 atomic_inc(&cache->stats.commit_count);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001443 cache->commit_requested = false;
Heinz Mauelshagenffcbcb62013-10-14 17:24:43 +02001444 r = dm_cache_commit(cache->cmd, false);
1445 cache->last_commit_jiffies = jiffies;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001446 }
1447
Heinz Mauelshagenffcbcb62013-10-14 17:24:43 +02001448 return r;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001449}
1450
1451static void process_deferred_bios(struct cache *cache)
1452{
1453 unsigned long flags;
1454 struct bio_list bios;
1455 struct bio *bio;
1456 struct prealloc structs;
1457
1458 memset(&structs, 0, sizeof(structs));
1459 bio_list_init(&bios);
1460
1461 spin_lock_irqsave(&cache->lock, flags);
1462 bio_list_merge(&bios, &cache->deferred_bios);
1463 bio_list_init(&cache->deferred_bios);
1464 spin_unlock_irqrestore(&cache->lock, flags);
1465
1466 while (!bio_list_empty(&bios)) {
1467 /*
1468 * If we've got no free migration structs, and processing
1469 * this bio might require one, we pause until there are some
1470 * prepared mappings to process.
1471 */
1472 if (prealloc_data_structs(cache, &structs)) {
1473 spin_lock_irqsave(&cache->lock, flags);
1474 bio_list_merge(&cache->deferred_bios, &bios);
1475 spin_unlock_irqrestore(&cache->lock, flags);
1476 break;
1477 }
1478
1479 bio = bio_list_pop(&bios);
1480
1481 if (bio->bi_rw & REQ_FLUSH)
1482 process_flush_bio(cache, bio);
1483 else if (bio->bi_rw & REQ_DISCARD)
1484 process_discard_bio(cache, bio);
1485 else
1486 process_bio(cache, &structs, bio);
1487 }
1488
1489 prealloc_free_structs(cache, &structs);
1490}
1491
1492static void process_deferred_flush_bios(struct cache *cache, bool submit_bios)
1493{
1494 unsigned long flags;
1495 struct bio_list bios;
1496 struct bio *bio;
1497
1498 bio_list_init(&bios);
1499
1500 spin_lock_irqsave(&cache->lock, flags);
1501 bio_list_merge(&bios, &cache->deferred_flush_bios);
1502 bio_list_init(&cache->deferred_flush_bios);
1503 spin_unlock_irqrestore(&cache->lock, flags);
1504
1505 while ((bio = bio_list_pop(&bios)))
1506 submit_bios ? generic_make_request(bio) : bio_io_error(bio);
1507}
1508
Joe Thornbere2e74d62013-03-20 17:21:27 +00001509static void process_deferred_writethrough_bios(struct cache *cache)
1510{
1511 unsigned long flags;
1512 struct bio_list bios;
1513 struct bio *bio;
1514
1515 bio_list_init(&bios);
1516
1517 spin_lock_irqsave(&cache->lock, flags);
1518 bio_list_merge(&bios, &cache->deferred_writethrough_bios);
1519 bio_list_init(&cache->deferred_writethrough_bios);
1520 spin_unlock_irqrestore(&cache->lock, flags);
1521
1522 while ((bio = bio_list_pop(&bios)))
1523 generic_make_request(bio);
1524}
1525
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001526static void writeback_some_dirty_blocks(struct cache *cache)
1527{
1528 int r = 0;
1529 dm_oblock_t oblock;
1530 dm_cblock_t cblock;
1531 struct prealloc structs;
1532 struct dm_bio_prison_cell *old_ocell;
1533
1534 memset(&structs, 0, sizeof(structs));
1535
1536 while (spare_migration_bandwidth(cache)) {
1537 if (prealloc_data_structs(cache, &structs))
1538 break;
1539
1540 r = policy_writeback_work(cache->policy, &oblock, &cblock);
1541 if (r)
1542 break;
1543
1544 r = get_cell(cache, oblock, &structs, &old_ocell);
1545 if (r) {
1546 policy_set_dirty(cache->policy, oblock);
1547 break;
1548 }
1549
1550 writeback(cache, &structs, oblock, cblock, old_ocell);
1551 }
1552
1553 prealloc_free_structs(cache, &structs);
1554}
1555
1556/*----------------------------------------------------------------
Joe Thornber65790ff2013-11-08 16:39:50 +00001557 * Invalidations.
1558 * Dropping something from the cache *without* writing back.
1559 *--------------------------------------------------------------*/
1560
1561static void process_invalidation_request(struct cache *cache, struct invalidation_request *req)
1562{
1563 int r = 0;
1564 uint64_t begin = from_cblock(req->cblocks->begin);
1565 uint64_t end = from_cblock(req->cblocks->end);
1566
1567 while (begin != end) {
1568 r = policy_remove_cblock(cache->policy, to_cblock(begin));
1569 if (!r) {
1570 r = dm_cache_remove_mapping(cache->cmd, to_cblock(begin));
1571 if (r)
1572 break;
1573
1574 } else if (r == -ENODATA) {
1575 /* harmless, already unmapped */
1576 r = 0;
1577
1578 } else {
1579 DMERR("policy_remove_cblock failed");
1580 break;
1581 }
1582
1583 begin++;
1584 }
1585
1586 cache->commit_requested = true;
1587
1588 req->err = r;
1589 atomic_set(&req->complete, 1);
1590
1591 wake_up(&req->result_wait);
1592}
1593
1594static void process_invalidation_requests(struct cache *cache)
1595{
1596 struct list_head list;
1597 struct invalidation_request *req, *tmp;
1598
1599 INIT_LIST_HEAD(&list);
1600 spin_lock(&cache->invalidation_lock);
1601 list_splice_init(&cache->invalidation_requests, &list);
1602 spin_unlock(&cache->invalidation_lock);
1603
1604 list_for_each_entry_safe (req, tmp, &list, list)
1605 process_invalidation_request(cache, req);
1606}
1607
1608/*----------------------------------------------------------------
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001609 * Main worker loop
1610 *--------------------------------------------------------------*/
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001611static bool is_quiescing(struct cache *cache)
1612{
Joe Thornber238f8362013-10-30 17:29:30 +00001613 return atomic_read(&cache->quiescing);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001614}
1615
Joe Thornber66cb1912013-10-30 17:11:58 +00001616static void ack_quiescing(struct cache *cache)
1617{
1618 if (is_quiescing(cache)) {
1619 atomic_inc(&cache->quiescing_ack);
1620 wake_up(&cache->quiescing_wait);
1621 }
1622}
1623
1624static void wait_for_quiescing_ack(struct cache *cache)
1625{
1626 wait_event(cache->quiescing_wait, atomic_read(&cache->quiescing_ack));
1627}
1628
1629static void start_quiescing(struct cache *cache)
1630{
Joe Thornber238f8362013-10-30 17:29:30 +00001631 atomic_inc(&cache->quiescing);
Joe Thornber66cb1912013-10-30 17:11:58 +00001632 wait_for_quiescing_ack(cache);
1633}
1634
1635static void stop_quiescing(struct cache *cache)
1636{
Joe Thornber238f8362013-10-30 17:29:30 +00001637 atomic_set(&cache->quiescing, 0);
Joe Thornber66cb1912013-10-30 17:11:58 +00001638 atomic_set(&cache->quiescing_ack, 0);
1639}
1640
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001641static void wait_for_migrations(struct cache *cache)
1642{
1643 wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations));
1644}
1645
1646static void stop_worker(struct cache *cache)
1647{
1648 cancel_delayed_work(&cache->waker);
1649 flush_workqueue(cache->wq);
1650}
1651
1652static void requeue_deferred_io(struct cache *cache)
1653{
1654 struct bio *bio;
1655 struct bio_list bios;
1656
1657 bio_list_init(&bios);
1658 bio_list_merge(&bios, &cache->deferred_bios);
1659 bio_list_init(&cache->deferred_bios);
1660
1661 while ((bio = bio_list_pop(&bios)))
1662 bio_endio(bio, DM_ENDIO_REQUEUE);
1663}
1664
1665static int more_work(struct cache *cache)
1666{
1667 if (is_quiescing(cache))
1668 return !list_empty(&cache->quiesced_migrations) ||
1669 !list_empty(&cache->completed_migrations) ||
1670 !list_empty(&cache->need_commit_migrations);
1671 else
1672 return !bio_list_empty(&cache->deferred_bios) ||
1673 !bio_list_empty(&cache->deferred_flush_bios) ||
Joe Thornbere2e74d62013-03-20 17:21:27 +00001674 !bio_list_empty(&cache->deferred_writethrough_bios) ||
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001675 !list_empty(&cache->quiesced_migrations) ||
1676 !list_empty(&cache->completed_migrations) ||
Joe Thornber65790ff2013-11-08 16:39:50 +00001677 !list_empty(&cache->need_commit_migrations) ||
1678 cache->invalidate;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001679}
1680
1681static void do_worker(struct work_struct *ws)
1682{
1683 struct cache *cache = container_of(ws, struct cache, worker);
1684
1685 do {
Joe Thornber66cb1912013-10-30 17:11:58 +00001686 if (!is_quiescing(cache)) {
1687 writeback_some_dirty_blocks(cache);
1688 process_deferred_writethrough_bios(cache);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001689 process_deferred_bios(cache);
Joe Thornber65790ff2013-11-08 16:39:50 +00001690 process_invalidation_requests(cache);
Joe Thornber66cb1912013-10-30 17:11:58 +00001691 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001692
1693 process_migrations(cache, &cache->quiesced_migrations, issue_copy);
1694 process_migrations(cache, &cache->completed_migrations, complete_migration);
1695
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001696 if (commit_if_needed(cache)) {
1697 process_deferred_flush_bios(cache, false);
1698
1699 /*
1700 * FIXME: rollback metadata or just go into a
1701 * failure mode and error everything
1702 */
1703 } else {
1704 process_deferred_flush_bios(cache, true);
1705 process_migrations(cache, &cache->need_commit_migrations,
1706 migration_success_post_commit);
1707 }
Joe Thornber66cb1912013-10-30 17:11:58 +00001708
1709 ack_quiescing(cache);
1710
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001711 } while (more_work(cache));
1712}
1713
1714/*
1715 * We want to commit periodically so that not too much
1716 * unwritten metadata builds up.
1717 */
1718static void do_waker(struct work_struct *ws)
1719{
1720 struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker);
Joe Thornberf8350da2013-05-10 14:37:16 +01001721 policy_tick(cache->policy);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001722 wake_worker(cache);
1723 queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD);
1724}
1725
1726/*----------------------------------------------------------------*/
1727
1728static int is_congested(struct dm_dev *dev, int bdi_bits)
1729{
1730 struct request_queue *q = bdev_get_queue(dev->bdev);
1731 return bdi_congested(&q->backing_dev_info, bdi_bits);
1732}
1733
1734static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1735{
1736 struct cache *cache = container_of(cb, struct cache, callbacks);
1737
1738 return is_congested(cache->origin_dev, bdi_bits) ||
1739 is_congested(cache->cache_dev, bdi_bits);
1740}
1741
1742/*----------------------------------------------------------------
1743 * Target methods
1744 *--------------------------------------------------------------*/
1745
1746/*
1747 * This function gets called on the error paths of the constructor, so we
1748 * have to cope with a partially initialised struct.
1749 */
1750static void destroy(struct cache *cache)
1751{
1752 unsigned i;
1753
1754 if (cache->next_migration)
1755 mempool_free(cache->next_migration, cache->migration_pool);
1756
1757 if (cache->migration_pool)
1758 mempool_destroy(cache->migration_pool);
1759
1760 if (cache->all_io_ds)
1761 dm_deferred_set_destroy(cache->all_io_ds);
1762
1763 if (cache->prison)
1764 dm_bio_prison_destroy(cache->prison);
1765
1766 if (cache->wq)
1767 destroy_workqueue(cache->wq);
1768
1769 if (cache->dirty_bitset)
1770 free_bitset(cache->dirty_bitset);
1771
1772 if (cache->discard_bitset)
1773 free_bitset(cache->discard_bitset);
1774
1775 if (cache->copier)
1776 dm_kcopyd_client_destroy(cache->copier);
1777
1778 if (cache->cmd)
1779 dm_cache_metadata_close(cache->cmd);
1780
1781 if (cache->metadata_dev)
1782 dm_put_device(cache->ti, cache->metadata_dev);
1783
1784 if (cache->origin_dev)
1785 dm_put_device(cache->ti, cache->origin_dev);
1786
1787 if (cache->cache_dev)
1788 dm_put_device(cache->ti, cache->cache_dev);
1789
1790 if (cache->policy)
1791 dm_cache_policy_destroy(cache->policy);
1792
1793 for (i = 0; i < cache->nr_ctr_args ; i++)
1794 kfree(cache->ctr_args[i]);
1795 kfree(cache->ctr_args);
1796
1797 kfree(cache);
1798}
1799
1800static void cache_dtr(struct dm_target *ti)
1801{
1802 struct cache *cache = ti->private;
1803
1804 destroy(cache);
1805}
1806
1807static sector_t get_dev_size(struct dm_dev *dev)
1808{
1809 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
1810}
1811
1812/*----------------------------------------------------------------*/
1813
1814/*
1815 * Construct a cache device mapping.
1816 *
1817 * cache <metadata dev> <cache dev> <origin dev> <block size>
1818 * <#feature args> [<feature arg>]*
1819 * <policy> <#policy args> [<policy arg>]*
1820 *
1821 * metadata dev : fast device holding the persistent metadata
1822 * cache dev : fast device holding cached data blocks
1823 * origin dev : slow device holding original data blocks
1824 * block size : cache unit size in sectors
1825 *
1826 * #feature args : number of feature arguments passed
1827 * feature args : writethrough. (The default is writeback.)
1828 *
1829 * policy : the replacement policy to use
1830 * #policy args : an even number of policy arguments corresponding
1831 * to key/value pairs passed to the policy
1832 * policy args : key/value pairs passed to the policy
1833 * E.g. 'sequential_threshold 1024'
1834 * See cache-policies.txt for details.
1835 *
1836 * Optional feature arguments are:
1837 * writethrough : write through caching that prohibits cache block
1838 * content from being different from origin block content.
1839 * Without this argument, the default behaviour is to write
1840 * back cache block contents later for performance reasons,
1841 * so they may differ from the corresponding origin blocks.
1842 */
1843struct cache_args {
1844 struct dm_target *ti;
1845
1846 struct dm_dev *metadata_dev;
1847
1848 struct dm_dev *cache_dev;
1849 sector_t cache_sectors;
1850
1851 struct dm_dev *origin_dev;
1852 sector_t origin_sectors;
1853
1854 uint32_t block_size;
1855
1856 const char *policy_name;
1857 int policy_argc;
1858 const char **policy_argv;
1859
1860 struct cache_features features;
1861};
1862
1863static void destroy_cache_args(struct cache_args *ca)
1864{
1865 if (ca->metadata_dev)
1866 dm_put_device(ca->ti, ca->metadata_dev);
1867
1868 if (ca->cache_dev)
1869 dm_put_device(ca->ti, ca->cache_dev);
1870
1871 if (ca->origin_dev)
1872 dm_put_device(ca->ti, ca->origin_dev);
1873
1874 kfree(ca);
1875}
1876
1877static bool at_least_one_arg(struct dm_arg_set *as, char **error)
1878{
1879 if (!as->argc) {
1880 *error = "Insufficient args";
1881 return false;
1882 }
1883
1884 return true;
1885}
1886
1887static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as,
1888 char **error)
1889{
1890 int r;
1891 sector_t metadata_dev_size;
1892 char b[BDEVNAME_SIZE];
1893
1894 if (!at_least_one_arg(as, error))
1895 return -EINVAL;
1896
1897 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
1898 &ca->metadata_dev);
1899 if (r) {
1900 *error = "Error opening metadata device";
1901 return r;
1902 }
1903
1904 metadata_dev_size = get_dev_size(ca->metadata_dev);
1905 if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING)
1906 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
1907 bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
1908
1909 return 0;
1910}
1911
1912static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as,
1913 char **error)
1914{
1915 int r;
1916
1917 if (!at_least_one_arg(as, error))
1918 return -EINVAL;
1919
1920 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
1921 &ca->cache_dev);
1922 if (r) {
1923 *error = "Error opening cache device";
1924 return r;
1925 }
1926 ca->cache_sectors = get_dev_size(ca->cache_dev);
1927
1928 return 0;
1929}
1930
1931static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as,
1932 char **error)
1933{
1934 int r;
1935
1936 if (!at_least_one_arg(as, error))
1937 return -EINVAL;
1938
1939 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
1940 &ca->origin_dev);
1941 if (r) {
1942 *error = "Error opening origin device";
1943 return r;
1944 }
1945
1946 ca->origin_sectors = get_dev_size(ca->origin_dev);
1947 if (ca->ti->len > ca->origin_sectors) {
1948 *error = "Device size larger than cached device";
1949 return -EINVAL;
1950 }
1951
1952 return 0;
1953}
1954
1955static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as,
1956 char **error)
1957{
Mike Snitzer05473042013-08-16 10:54:19 -04001958 unsigned long block_size;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001959
1960 if (!at_least_one_arg(as, error))
1961 return -EINVAL;
1962
Mike Snitzer05473042013-08-16 10:54:19 -04001963 if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size ||
1964 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
1965 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
1966 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001967 *error = "Invalid data block size";
1968 return -EINVAL;
1969 }
1970
Mike Snitzer05473042013-08-16 10:54:19 -04001971 if (block_size > ca->cache_sectors) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001972 *error = "Data block size is larger than the cache device";
1973 return -EINVAL;
1974 }
1975
Mike Snitzer05473042013-08-16 10:54:19 -04001976 ca->block_size = block_size;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001977
1978 return 0;
1979}
1980
1981static void init_features(struct cache_features *cf)
1982{
1983 cf->mode = CM_WRITE;
Joe Thornber2ee57d52013-10-24 14:10:29 -04001984 cf->io_mode = CM_IO_WRITEBACK;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00001985}
1986
1987static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
1988 char **error)
1989{
1990 static struct dm_arg _args[] = {
1991 {0, 1, "Invalid number of cache feature arguments"},
1992 };
1993
1994 int r;
1995 unsigned argc;
1996 const char *arg;
1997 struct cache_features *cf = &ca->features;
1998
1999 init_features(cf);
2000
2001 r = dm_read_arg_group(_args, as, &argc, error);
2002 if (r)
2003 return -EINVAL;
2004
2005 while (argc--) {
2006 arg = dm_shift_arg(as);
2007
2008 if (!strcasecmp(arg, "writeback"))
Joe Thornber2ee57d52013-10-24 14:10:29 -04002009 cf->io_mode = CM_IO_WRITEBACK;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002010
2011 else if (!strcasecmp(arg, "writethrough"))
Joe Thornber2ee57d52013-10-24 14:10:29 -04002012 cf->io_mode = CM_IO_WRITETHROUGH;
2013
2014 else if (!strcasecmp(arg, "passthrough"))
2015 cf->io_mode = CM_IO_PASSTHROUGH;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002016
2017 else {
2018 *error = "Unrecognised cache feature requested";
2019 return -EINVAL;
2020 }
2021 }
2022
2023 return 0;
2024}
2025
2026static int parse_policy(struct cache_args *ca, struct dm_arg_set *as,
2027 char **error)
2028{
2029 static struct dm_arg _args[] = {
2030 {0, 1024, "Invalid number of policy arguments"},
2031 };
2032
2033 int r;
2034
2035 if (!at_least_one_arg(as, error))
2036 return -EINVAL;
2037
2038 ca->policy_name = dm_shift_arg(as);
2039
2040 r = dm_read_arg_group(_args, as, &ca->policy_argc, error);
2041 if (r)
2042 return -EINVAL;
2043
2044 ca->policy_argv = (const char **)as->argv;
2045 dm_consume_args(as, ca->policy_argc);
2046
2047 return 0;
2048}
2049
2050static int parse_cache_args(struct cache_args *ca, int argc, char **argv,
2051 char **error)
2052{
2053 int r;
2054 struct dm_arg_set as;
2055
2056 as.argc = argc;
2057 as.argv = argv;
2058
2059 r = parse_metadata_dev(ca, &as, error);
2060 if (r)
2061 return r;
2062
2063 r = parse_cache_dev(ca, &as, error);
2064 if (r)
2065 return r;
2066
2067 r = parse_origin_dev(ca, &as, error);
2068 if (r)
2069 return r;
2070
2071 r = parse_block_size(ca, &as, error);
2072 if (r)
2073 return r;
2074
2075 r = parse_features(ca, &as, error);
2076 if (r)
2077 return r;
2078
2079 r = parse_policy(ca, &as, error);
2080 if (r)
2081 return r;
2082
2083 return 0;
2084}
2085
2086/*----------------------------------------------------------------*/
2087
2088static struct kmem_cache *migration_cache;
2089
Alasdair G Kergon2c73c472013-05-10 14:37:21 +01002090#define NOT_CORE_OPTION 1
2091
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002092static int process_config_option(struct cache *cache, const char *key, const char *value)
Alasdair G Kergon2c73c472013-05-10 14:37:21 +01002093{
2094 unsigned long tmp;
2095
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002096 if (!strcasecmp(key, "migration_threshold")) {
2097 if (kstrtoul(value, 10, &tmp))
Alasdair G Kergon2c73c472013-05-10 14:37:21 +01002098 return -EINVAL;
2099
2100 cache->migration_threshold = tmp;
2101 return 0;
2102 }
2103
2104 return NOT_CORE_OPTION;
2105}
2106
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002107static int set_config_value(struct cache *cache, const char *key, const char *value)
2108{
2109 int r = process_config_option(cache, key, value);
2110
2111 if (r == NOT_CORE_OPTION)
2112 r = policy_set_config_value(cache->policy, key, value);
2113
2114 if (r)
2115 DMWARN("bad config value for %s: %s", key, value);
2116
2117 return r;
2118}
2119
2120static int set_config_values(struct cache *cache, int argc, const char **argv)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002121{
2122 int r = 0;
2123
2124 if (argc & 1) {
2125 DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs.");
2126 return -EINVAL;
2127 }
2128
2129 while (argc) {
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002130 r = set_config_value(cache, argv[0], argv[1]);
2131 if (r)
2132 break;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002133
2134 argc -= 2;
2135 argv += 2;
2136 }
2137
2138 return r;
2139}
2140
2141static int create_cache_policy(struct cache *cache, struct cache_args *ca,
2142 char **error)
2143{
Mikulas Patocka4cb3e1d2013-10-01 18:35:39 -04002144 struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name,
2145 cache->cache_size,
2146 cache->origin_sectors,
2147 cache->sectors_per_block);
2148 if (IS_ERR(p)) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002149 *error = "Error creating cache's policy";
Mikulas Patocka4cb3e1d2013-10-01 18:35:39 -04002150 return PTR_ERR(p);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002151 }
Mikulas Patocka4cb3e1d2013-10-01 18:35:39 -04002152 cache->policy = p;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002153
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002154 return 0;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002155}
2156
Joe Thornberf8350da2013-05-10 14:37:16 +01002157#define DEFAULT_MIGRATION_THRESHOLD 2048
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002158
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002159static int cache_create(struct cache_args *ca, struct cache **result)
2160{
2161 int r = 0;
2162 char **error = &ca->ti->error;
2163 struct cache *cache;
2164 struct dm_target *ti = ca->ti;
2165 dm_block_t origin_blocks;
2166 struct dm_cache_metadata *cmd;
2167 bool may_format = ca->features.mode == CM_WRITE;
2168
2169 cache = kzalloc(sizeof(*cache), GFP_KERNEL);
2170 if (!cache)
2171 return -ENOMEM;
2172
2173 cache->ti = ca->ti;
2174 ti->private = cache;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002175 ti->num_flush_bios = 2;
2176 ti->flush_supported = true;
2177
2178 ti->num_discard_bios = 1;
2179 ti->discards_supported = true;
2180 ti->discard_zeroes_data_unsupported = true;
2181
Joe Thornber8c5008f2013-05-10 14:37:18 +01002182 cache->features = ca->features;
Mike Snitzer19b00922013-04-05 15:36:34 +01002183 ti->per_bio_data_size = get_per_bio_data_size(cache);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002184
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002185 cache->callbacks.congested_fn = cache_is_congested;
2186 dm_table_add_target_callbacks(ti->table, &cache->callbacks);
2187
2188 cache->metadata_dev = ca->metadata_dev;
2189 cache->origin_dev = ca->origin_dev;
2190 cache->cache_dev = ca->cache_dev;
2191
2192 ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL;
2193
2194 /* FIXME: factor out this whole section */
2195 origin_blocks = cache->origin_sectors = ca->origin_sectors;
Joe Thornber414dd672013-03-20 17:21:25 +00002196 origin_blocks = block_div(origin_blocks, ca->block_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002197 cache->origin_blocks = to_oblock(origin_blocks);
2198
2199 cache->sectors_per_block = ca->block_size;
2200 if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) {
2201 r = -EINVAL;
2202 goto bad;
2203 }
2204
2205 if (ca->block_size & (ca->block_size - 1)) {
2206 dm_block_t cache_size = ca->cache_sectors;
2207
2208 cache->sectors_per_block_shift = -1;
Joe Thornber414dd672013-03-20 17:21:25 +00002209 cache_size = block_div(cache_size, ca->block_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002210 cache->cache_size = to_cblock(cache_size);
2211 } else {
2212 cache->sectors_per_block_shift = __ffs(ca->block_size);
2213 cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift);
2214 }
2215
2216 r = create_cache_policy(cache, ca, error);
2217 if (r)
2218 goto bad;
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002219
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002220 cache->policy_nr_args = ca->policy_argc;
Joe Thornber2f14f4b2013-05-10 14:37:21 +01002221 cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD;
2222
2223 r = set_config_values(cache, ca->policy_argc, ca->policy_argv);
2224 if (r) {
2225 *error = "Error setting cache policy's config values";
2226 goto bad;
2227 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002228
2229 cmd = dm_cache_metadata_open(cache->metadata_dev->bdev,
2230 ca->block_size, may_format,
2231 dm_cache_policy_get_hint_size(cache->policy));
2232 if (IS_ERR(cmd)) {
2233 *error = "Error creating metadata object";
2234 r = PTR_ERR(cmd);
2235 goto bad;
2236 }
2237 cache->cmd = cmd;
2238
Joe Thornber2ee57d52013-10-24 14:10:29 -04002239 if (passthrough_mode(&cache->features)) {
2240 bool all_clean;
2241
2242 r = dm_cache_metadata_all_clean(cache->cmd, &all_clean);
2243 if (r) {
2244 *error = "dm_cache_metadata_all_clean() failed";
2245 goto bad;
2246 }
2247
2248 if (!all_clean) {
2249 *error = "Cannot enter passthrough mode unless all blocks are clean";
2250 r = -EINVAL;
2251 goto bad;
2252 }
2253 }
2254
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002255 spin_lock_init(&cache->lock);
2256 bio_list_init(&cache->deferred_bios);
2257 bio_list_init(&cache->deferred_flush_bios);
Joe Thornbere2e74d62013-03-20 17:21:27 +00002258 bio_list_init(&cache->deferred_writethrough_bios);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002259 INIT_LIST_HEAD(&cache->quiesced_migrations);
2260 INIT_LIST_HEAD(&cache->completed_migrations);
2261 INIT_LIST_HEAD(&cache->need_commit_migrations);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002262 atomic_set(&cache->nr_migrations, 0);
2263 init_waitqueue_head(&cache->migration_wait);
2264
Joe Thornber66cb1912013-10-30 17:11:58 +00002265 init_waitqueue_head(&cache->quiescing_wait);
Joe Thornber238f8362013-10-30 17:29:30 +00002266 atomic_set(&cache->quiescing, 0);
Joe Thornber66cb1912013-10-30 17:11:58 +00002267 atomic_set(&cache->quiescing_ack, 0);
2268
Wei Yongjunfa4d6832013-05-10 14:37:14 +01002269 r = -ENOMEM;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002270 cache->nr_dirty = 0;
2271 cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size));
2272 if (!cache->dirty_bitset) {
2273 *error = "could not allocate dirty bitset";
2274 goto bad;
2275 }
2276 clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
2277
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002278 cache->discard_nr_blocks = cache->origin_blocks;
2279 cache->discard_bitset = alloc_bitset(from_oblock(cache->discard_nr_blocks));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002280 if (!cache->discard_bitset) {
2281 *error = "could not allocate discard bitset";
2282 goto bad;
2283 }
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002284 clear_bitset(cache->discard_bitset, from_oblock(cache->discard_nr_blocks));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002285
2286 cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2287 if (IS_ERR(cache->copier)) {
2288 *error = "could not create kcopyd client";
2289 r = PTR_ERR(cache->copier);
2290 goto bad;
2291 }
2292
2293 cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2294 if (!cache->wq) {
2295 *error = "could not create workqueue for metadata object";
2296 goto bad;
2297 }
2298 INIT_WORK(&cache->worker, do_worker);
2299 INIT_DELAYED_WORK(&cache->waker, do_waker);
2300 cache->last_commit_jiffies = jiffies;
2301
2302 cache->prison = dm_bio_prison_create(PRISON_CELLS);
2303 if (!cache->prison) {
2304 *error = "could not create bio prison";
2305 goto bad;
2306 }
2307
2308 cache->all_io_ds = dm_deferred_set_create();
2309 if (!cache->all_io_ds) {
2310 *error = "could not create all_io deferred set";
2311 goto bad;
2312 }
2313
2314 cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE,
2315 migration_cache);
2316 if (!cache->migration_pool) {
2317 *error = "Error creating cache's migration mempool";
2318 goto bad;
2319 }
2320
2321 cache->next_migration = NULL;
2322
2323 cache->need_tick_bio = true;
2324 cache->sized = false;
Joe Thornber65790ff2013-11-08 16:39:50 +00002325 cache->invalidate = false;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002326 cache->commit_requested = false;
2327 cache->loaded_mappings = false;
2328 cache->loaded_discards = false;
2329
2330 load_stats(cache);
2331
2332 atomic_set(&cache->stats.demotion, 0);
2333 atomic_set(&cache->stats.promotion, 0);
2334 atomic_set(&cache->stats.copies_avoided, 0);
2335 atomic_set(&cache->stats.cache_cell_clash, 0);
2336 atomic_set(&cache->stats.commit_count, 0);
2337 atomic_set(&cache->stats.discard_count, 0);
2338
Joe Thornber65790ff2013-11-08 16:39:50 +00002339 spin_lock_init(&cache->invalidation_lock);
2340 INIT_LIST_HEAD(&cache->invalidation_requests);
2341
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002342 *result = cache;
2343 return 0;
2344
2345bad:
2346 destroy(cache);
2347 return r;
2348}
2349
2350static int copy_ctr_args(struct cache *cache, int argc, const char **argv)
2351{
2352 unsigned i;
2353 const char **copy;
2354
2355 copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL);
2356 if (!copy)
2357 return -ENOMEM;
2358 for (i = 0; i < argc; i++) {
2359 copy[i] = kstrdup(argv[i], GFP_KERNEL);
2360 if (!copy[i]) {
2361 while (i--)
2362 kfree(copy[i]);
2363 kfree(copy);
2364 return -ENOMEM;
2365 }
2366 }
2367
2368 cache->nr_ctr_args = argc;
2369 cache->ctr_args = copy;
2370
2371 return 0;
2372}
2373
2374static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv)
2375{
2376 int r = -EINVAL;
2377 struct cache_args *ca;
2378 struct cache *cache = NULL;
2379
2380 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2381 if (!ca) {
2382 ti->error = "Error allocating memory for cache";
2383 return -ENOMEM;
2384 }
2385 ca->ti = ti;
2386
2387 r = parse_cache_args(ca, argc, argv, &ti->error);
2388 if (r)
2389 goto out;
2390
2391 r = cache_create(ca, &cache);
Heinz Mauelshagen617a0b82013-03-20 17:21:26 +00002392 if (r)
2393 goto out;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002394
2395 r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3);
2396 if (r) {
2397 destroy(cache);
2398 goto out;
2399 }
2400
2401 ti->private = cache;
2402
2403out:
2404 destroy_cache_args(ca);
2405 return r;
2406}
2407
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002408static int cache_map(struct dm_target *ti, struct bio *bio)
2409{
2410 struct cache *cache = ti->private;
2411
2412 int r;
2413 dm_oblock_t block = get_bio_block(cache, bio);
Mike Snitzer19b00922013-04-05 15:36:34 +01002414 size_t pb_data_size = get_per_bio_data_size(cache);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002415 bool can_migrate = false;
2416 bool discarded_block;
2417 struct dm_bio_prison_cell *cell;
2418 struct policy_result lookup_result;
Heinz Mauelshagene893fba2014-03-12 16:13:39 +01002419 struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002420
Heinz Mauelshagene893fba2014-03-12 16:13:39 +01002421 if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) {
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002422 /*
2423 * This can only occur if the io goes to a partial block at
2424 * the end of the origin device. We don't cache these.
2425 * Just remap to the origin and carry on.
2426 */
Heinz Mauelshagene893fba2014-03-12 16:13:39 +01002427 remap_to_origin(cache, bio);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002428 return DM_MAPIO_REMAPPED;
2429 }
2430
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002431 if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) {
2432 defer_bio(cache, bio);
2433 return DM_MAPIO_SUBMITTED;
2434 }
2435
2436 /*
2437 * Check to see if that block is currently migrating.
2438 */
2439 cell = alloc_prison_cell(cache);
2440 if (!cell) {
2441 defer_bio(cache, bio);
2442 return DM_MAPIO_SUBMITTED;
2443 }
2444
2445 r = bio_detain(cache, block, bio, cell,
2446 (cell_free_fn) free_prison_cell,
2447 cache, &cell);
2448 if (r) {
2449 if (r < 0)
2450 defer_bio(cache, bio);
2451
2452 return DM_MAPIO_SUBMITTED;
2453 }
2454
2455 discarded_block = is_discarded_oblock(cache, block);
2456
2457 r = policy_map(cache->policy, block, false, can_migrate, discarded_block,
2458 bio, &lookup_result);
2459 if (r == -EWOULDBLOCK) {
2460 cell_defer(cache, cell, true);
2461 return DM_MAPIO_SUBMITTED;
2462
2463 } else if (r) {
2464 DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r);
2465 bio_io_error(bio);
2466 return DM_MAPIO_SUBMITTED;
2467 }
2468
Joe Thornber2ee57d52013-10-24 14:10:29 -04002469 r = DM_MAPIO_REMAPPED;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002470 switch (lookup_result.op) {
2471 case POLICY_HIT:
Joe Thornber2ee57d52013-10-24 14:10:29 -04002472 if (passthrough_mode(&cache->features)) {
2473 if (bio_data_dir(bio) == WRITE) {
2474 /*
2475 * We need to invalidate this block, so
2476 * defer for the worker thread.
2477 */
2478 cell_defer(cache, cell, true);
2479 r = DM_MAPIO_SUBMITTED;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002480
Joe Thornber2ee57d52013-10-24 14:10:29 -04002481 } else {
2482 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
2483 inc_miss_counter(cache, bio);
2484 remap_to_origin_clear_discard(cache, bio, block);
Joe Thornbere2e74d62013-03-20 17:21:27 +00002485
Joe Thornber2ee57d52013-10-24 14:10:29 -04002486 cell_defer(cache, cell, false);
2487 }
2488
2489 } else {
2490 inc_hit_counter(cache, bio);
2491
2492 if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) &&
2493 !is_dirty(cache, lookup_result.cblock))
2494 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
2495 else
2496 remap_to_cache_dirty(cache, bio, block, lookup_result.cblock);
2497
2498 cell_defer(cache, cell, false);
2499 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002500 break;
2501
2502 case POLICY_MISS:
2503 inc_miss_counter(cache, bio);
2504 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
2505
2506 if (pb->req_nr != 0) {
2507 /*
2508 * This is a duplicate writethrough io that is no
2509 * longer needed because the block has been demoted.
2510 */
2511 bio_endio(bio, 0);
2512 cell_defer(cache, cell, false);
2513 return DM_MAPIO_SUBMITTED;
2514 } else {
2515 remap_to_origin_clear_discard(cache, bio, block);
2516 cell_defer(cache, cell, false);
2517 }
2518 break;
2519
2520 default:
2521 DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__,
2522 (unsigned) lookup_result.op);
2523 bio_io_error(bio);
Joe Thornber2ee57d52013-10-24 14:10:29 -04002524 r = DM_MAPIO_SUBMITTED;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002525 }
2526
Joe Thornber2ee57d52013-10-24 14:10:29 -04002527 return r;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002528}
2529
2530static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
2531{
2532 struct cache *cache = ti->private;
2533 unsigned long flags;
Mike Snitzer19b00922013-04-05 15:36:34 +01002534 size_t pb_data_size = get_per_bio_data_size(cache);
2535 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002536
2537 if (pb->tick) {
2538 policy_tick(cache->policy);
2539
2540 spin_lock_irqsave(&cache->lock, flags);
2541 cache->need_tick_bio = true;
2542 spin_unlock_irqrestore(&cache->lock, flags);
2543 }
2544
2545 check_for_quiesced_migrations(cache, pb);
2546
2547 return 0;
2548}
2549
2550static int write_dirty_bitset(struct cache *cache)
2551{
2552 unsigned i, r;
2553
2554 for (i = 0; i < from_cblock(cache->cache_size); i++) {
2555 r = dm_cache_set_dirty(cache->cmd, to_cblock(i),
2556 is_dirty(cache, to_cblock(i)));
2557 if (r)
2558 return r;
2559 }
2560
2561 return 0;
2562}
2563
2564static int write_discard_bitset(struct cache *cache)
2565{
2566 unsigned i, r;
2567
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002568 r = dm_cache_discard_bitset_resize(cache->cmd, cache->sectors_per_block,
2569 cache->origin_blocks);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002570 if (r) {
2571 DMERR("could not resize on-disk discard bitset");
2572 return r;
2573 }
2574
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002575 for (i = 0; i < from_oblock(cache->discard_nr_blocks); i++) {
2576 r = dm_cache_set_discard(cache->cmd, to_oblock(i),
2577 is_discarded(cache, to_oblock(i)));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002578 if (r)
2579 return r;
2580 }
2581
2582 return 0;
2583}
2584
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002585/*
2586 * returns true on success
2587 */
2588static bool sync_metadata(struct cache *cache)
2589{
2590 int r1, r2, r3, r4;
2591
2592 r1 = write_dirty_bitset(cache);
2593 if (r1)
2594 DMERR("could not write dirty bitset");
2595
2596 r2 = write_discard_bitset(cache);
2597 if (r2)
2598 DMERR("could not write discard bitset");
2599
2600 save_stats(cache);
2601
Joe Thornber05966612014-04-03 16:16:44 +01002602 r3 = dm_cache_write_hints(cache->cmd, cache->policy);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002603 if (r3)
2604 DMERR("could not write hints");
2605
2606 /*
2607 * If writing the above metadata failed, we still commit, but don't
2608 * set the clean shutdown flag. This will effectively force every
2609 * dirty bit to be set on reload.
2610 */
2611 r4 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3);
2612 if (r4)
2613 DMERR("could not write cache metadata. Data loss may occur.");
2614
2615 return !r1 && !r2 && !r3 && !r4;
2616}
2617
2618static void cache_postsuspend(struct dm_target *ti)
2619{
2620 struct cache *cache = ti->private;
2621
2622 start_quiescing(cache);
2623 wait_for_migrations(cache);
2624 stop_worker(cache);
2625 requeue_deferred_io(cache);
2626 stop_quiescing(cache);
2627
2628 (void) sync_metadata(cache);
2629}
2630
2631static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
2632 bool dirty, uint32_t hint, bool hint_valid)
2633{
2634 int r;
2635 struct cache *cache = context;
2636
2637 r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid);
2638 if (r)
2639 return r;
2640
2641 if (dirty)
2642 set_dirty(cache, oblock, cblock);
2643 else
2644 clear_dirty(cache, oblock, cblock);
2645
2646 return 0;
2647}
2648
2649static int load_discard(void *context, sector_t discard_block_size,
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002650 dm_oblock_t oblock, bool discard)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002651{
2652 struct cache *cache = context;
2653
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002654 if (discard)
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002655 set_discard(cache, oblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002656 else
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04002657 clear_discard(cache, oblock);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002658
2659 return 0;
2660}
2661
Joe Thornberf494a9c2013-10-31 13:55:49 -04002662static dm_cblock_t get_cache_dev_size(struct cache *cache)
2663{
2664 sector_t size = get_dev_size(cache->cache_dev);
2665 (void) sector_div(size, cache->sectors_per_block);
2666 return to_cblock(size);
2667}
2668
2669static bool can_resize(struct cache *cache, dm_cblock_t new_size)
2670{
2671 if (from_cblock(new_size) > from_cblock(cache->cache_size))
2672 return true;
2673
2674 /*
2675 * We can't drop a dirty block when shrinking the cache.
2676 */
2677 while (from_cblock(new_size) < from_cblock(cache->cache_size)) {
2678 new_size = to_cblock(from_cblock(new_size) + 1);
2679 if (is_dirty(cache, new_size)) {
2680 DMERR("unable to shrink cache; cache block %llu is dirty",
2681 (unsigned long long) from_cblock(new_size));
2682 return false;
2683 }
2684 }
2685
2686 return true;
2687}
2688
2689static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size)
2690{
2691 int r;
2692
Vincent Pelletier08844802013-11-30 12:58:42 +01002693 r = dm_cache_resize(cache->cmd, new_size);
Joe Thornberf494a9c2013-10-31 13:55:49 -04002694 if (r) {
2695 DMERR("could not resize cache metadata");
2696 return r;
2697 }
2698
2699 cache->cache_size = new_size;
2700
2701 return 0;
2702}
2703
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002704static int cache_preresume(struct dm_target *ti)
2705{
2706 int r = 0;
2707 struct cache *cache = ti->private;
Joe Thornberf494a9c2013-10-31 13:55:49 -04002708 dm_cblock_t csize = get_cache_dev_size(cache);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002709
2710 /*
2711 * Check to see if the cache has resized.
2712 */
Joe Thornberf494a9c2013-10-31 13:55:49 -04002713 if (!cache->sized) {
2714 r = resize_cache_dev(cache, csize);
2715 if (r)
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002716 return r;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002717
2718 cache->sized = true;
Joe Thornberf494a9c2013-10-31 13:55:49 -04002719
2720 } else if (csize != cache->cache_size) {
2721 if (!can_resize(cache, csize))
2722 return -EINVAL;
2723
2724 r = resize_cache_dev(cache, csize);
2725 if (r)
2726 return r;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002727 }
2728
2729 if (!cache->loaded_mappings) {
Mike Snitzerea2dd8c2013-03-20 17:21:28 +00002730 r = dm_cache_load_mappings(cache->cmd, cache->policy,
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002731 load_mapping, cache);
2732 if (r) {
2733 DMERR("could not load cache mappings");
2734 return r;
2735 }
2736
2737 cache->loaded_mappings = true;
2738 }
2739
2740 if (!cache->loaded_discards) {
2741 r = dm_cache_load_discards(cache->cmd, load_discard, cache);
2742 if (r) {
2743 DMERR("could not load origin discards");
2744 return r;
2745 }
2746
2747 cache->loaded_discards = true;
2748 }
2749
2750 return r;
2751}
2752
2753static void cache_resume(struct dm_target *ti)
2754{
2755 struct cache *cache = ti->private;
2756
2757 cache->need_tick_bio = true;
2758 do_waker(&cache->waker.work);
2759}
2760
2761/*
2762 * Status format:
2763 *
Mike Snitzer6a388612014-01-09 16:04:12 -05002764 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
2765 * <cache block size> <#used cache blocks>/<#total cache blocks>
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002766 * <#read hits> <#read misses> <#write hits> <#write misses>
Mike Snitzer6a388612014-01-09 16:04:12 -05002767 * <#demotions> <#promotions> <#dirty>
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002768 * <#features> <features>*
2769 * <#core args> <core args>
Mike Snitzer2e68c4e2014-01-15 21:06:55 -05002770 * <policy name> <#policy args> <policy args>*
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002771 */
2772static void cache_status(struct dm_target *ti, status_type_t type,
2773 unsigned status_flags, char *result, unsigned maxlen)
2774{
2775 int r = 0;
2776 unsigned i;
2777 ssize_t sz = 0;
2778 dm_block_t nr_free_blocks_metadata = 0;
2779 dm_block_t nr_blocks_metadata = 0;
2780 char buf[BDEVNAME_SIZE];
2781 struct cache *cache = ti->private;
2782 dm_cblock_t residency;
2783
2784 switch (type) {
2785 case STATUSTYPE_INFO:
2786 /* Commit to ensure statistics aren't out-of-date */
2787 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) {
2788 r = dm_cache_commit(cache->cmd, false);
2789 if (r)
2790 DMERR("could not commit metadata for accurate status");
2791 }
2792
2793 r = dm_cache_get_free_metadata_block_count(cache->cmd,
2794 &nr_free_blocks_metadata);
2795 if (r) {
2796 DMERR("could not get metadata free block count");
2797 goto err;
2798 }
2799
2800 r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata);
2801 if (r) {
2802 DMERR("could not get metadata device size");
2803 goto err;
2804 }
2805
2806 residency = policy_residency(cache->policy);
2807
Mike Snitzer6a388612014-01-09 16:04:12 -05002808 DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %llu ",
2809 (unsigned)(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002810 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2811 (unsigned long long)nr_blocks_metadata,
Mike Snitzer6a388612014-01-09 16:04:12 -05002812 cache->sectors_per_block,
2813 (unsigned long long) from_cblock(residency),
2814 (unsigned long long) from_cblock(cache->cache_size),
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002815 (unsigned) atomic_read(&cache->stats.read_hit),
2816 (unsigned) atomic_read(&cache->stats.read_miss),
2817 (unsigned) atomic_read(&cache->stats.write_hit),
2818 (unsigned) atomic_read(&cache->stats.write_miss),
2819 (unsigned) atomic_read(&cache->stats.demotion),
2820 (unsigned) atomic_read(&cache->stats.promotion),
Mike Snitzer6a388612014-01-09 16:04:12 -05002821 (unsigned long long) from_cblock(cache->nr_dirty));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002822
Joe Thornber2ee57d52013-10-24 14:10:29 -04002823 if (writethrough_mode(&cache->features))
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002824 DMEMIT("1 writethrough ");
Joe Thornber2ee57d52013-10-24 14:10:29 -04002825
2826 else if (passthrough_mode(&cache->features))
2827 DMEMIT("1 passthrough ");
2828
2829 else if (writeback_mode(&cache->features))
2830 DMEMIT("1 writeback ");
2831
2832 else {
2833 DMERR("internal error: unknown io mode: %d", (int) cache->features.io_mode);
2834 goto err;
2835 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002836
2837 DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
Mike Snitzer2e68c4e2014-01-15 21:06:55 -05002838
2839 DMEMIT("%s ", dm_cache_policy_get_name(cache->policy));
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002840 if (sz < maxlen) {
2841 r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz);
2842 if (r)
2843 DMERR("policy_emit_config_values returned %d", r);
2844 }
2845
2846 break;
2847
2848 case STATUSTYPE_TABLE:
2849 format_dev_t(buf, cache->metadata_dev->bdev->bd_dev);
2850 DMEMIT("%s ", buf);
2851 format_dev_t(buf, cache->cache_dev->bdev->bd_dev);
2852 DMEMIT("%s ", buf);
2853 format_dev_t(buf, cache->origin_dev->bdev->bd_dev);
2854 DMEMIT("%s", buf);
2855
2856 for (i = 0; i < cache->nr_ctr_args - 1; i++)
2857 DMEMIT(" %s", cache->ctr_args[i]);
2858 if (cache->nr_ctr_args)
2859 DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]);
2860 }
2861
2862 return;
2863
2864err:
2865 DMEMIT("Error");
2866}
2867
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002868/*
Joe Thornber65790ff2013-11-08 16:39:50 +00002869 * A cache block range can take two forms:
2870 *
2871 * i) A single cblock, eg. '3456'
2872 * ii) A begin and end cblock with dots between, eg. 123-234
2873 */
2874static int parse_cblock_range(struct cache *cache, const char *str,
2875 struct cblock_range *result)
2876{
2877 char dummy;
2878 uint64_t b, e;
2879 int r;
2880
2881 /*
2882 * Try and parse form (ii) first.
2883 */
2884 r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy);
2885 if (r < 0)
2886 return r;
2887
2888 if (r == 2) {
2889 result->begin = to_cblock(b);
2890 result->end = to_cblock(e);
2891 return 0;
2892 }
2893
2894 /*
2895 * That didn't work, try form (i).
2896 */
2897 r = sscanf(str, "%llu%c", &b, &dummy);
2898 if (r < 0)
2899 return r;
2900
2901 if (r == 1) {
2902 result->begin = to_cblock(b);
2903 result->end = to_cblock(from_cblock(result->begin) + 1u);
2904 return 0;
2905 }
2906
2907 DMERR("invalid cblock range '%s'", str);
2908 return -EINVAL;
2909}
2910
2911static int validate_cblock_range(struct cache *cache, struct cblock_range *range)
2912{
2913 uint64_t b = from_cblock(range->begin);
2914 uint64_t e = from_cblock(range->end);
2915 uint64_t n = from_cblock(cache->cache_size);
2916
2917 if (b >= n) {
2918 DMERR("begin cblock out of range: %llu >= %llu", b, n);
2919 return -EINVAL;
2920 }
2921
2922 if (e > n) {
2923 DMERR("end cblock out of range: %llu > %llu", e, n);
2924 return -EINVAL;
2925 }
2926
2927 if (b >= e) {
2928 DMERR("invalid cblock range: %llu >= %llu", b, e);
2929 return -EINVAL;
2930 }
2931
2932 return 0;
2933}
2934
2935static int request_invalidation(struct cache *cache, struct cblock_range *range)
2936{
2937 struct invalidation_request req;
2938
2939 INIT_LIST_HEAD(&req.list);
2940 req.cblocks = range;
2941 atomic_set(&req.complete, 0);
2942 req.err = 0;
2943 init_waitqueue_head(&req.result_wait);
2944
2945 spin_lock(&cache->invalidation_lock);
2946 list_add(&req.list, &cache->invalidation_requests);
2947 spin_unlock(&cache->invalidation_lock);
2948 wake_worker(cache);
2949
2950 wait_event(req.result_wait, atomic_read(&req.complete));
2951 return req.err;
2952}
2953
2954static int process_invalidate_cblocks_message(struct cache *cache, unsigned count,
2955 const char **cblock_ranges)
2956{
2957 int r = 0;
2958 unsigned i;
2959 struct cblock_range range;
2960
2961 if (!passthrough_mode(&cache->features)) {
2962 DMERR("cache has to be in passthrough mode for invalidation");
2963 return -EPERM;
2964 }
2965
2966 for (i = 0; i < count; i++) {
2967 r = parse_cblock_range(cache, cblock_ranges[i], &range);
2968 if (r)
2969 break;
2970
2971 r = validate_cblock_range(cache, &range);
2972 if (r)
2973 break;
2974
2975 /*
2976 * Pass begin and end origin blocks to the worker and wake it.
2977 */
2978 r = request_invalidation(cache, &range);
2979 if (r)
2980 break;
2981 }
2982
2983 return r;
2984}
2985
2986/*
2987 * Supports
2988 * "<key> <value>"
2989 * and
2990 * "invalidate_cblocks [(<begin>)|(<begin>-<end>)]*
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002991 *
2992 * The key migration_threshold is supported by the cache target core.
2993 */
2994static int cache_message(struct dm_target *ti, unsigned argc, char **argv)
2995{
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00002996 struct cache *cache = ti->private;
2997
Joe Thornber65790ff2013-11-08 16:39:50 +00002998 if (!argc)
2999 return -EINVAL;
3000
Mike Snitzer7b6b2bc2013-11-12 12:17:43 -05003001 if (!strcasecmp(argv[0], "invalidate_cblocks"))
Joe Thornber65790ff2013-11-08 16:39:50 +00003002 return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1);
3003
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003004 if (argc != 2)
3005 return -EINVAL;
3006
Joe Thornber2f14f4b2013-05-10 14:37:21 +01003007 return set_config_value(cache, argv[0], argv[1]);
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003008}
3009
3010static int cache_iterate_devices(struct dm_target *ti,
3011 iterate_devices_callout_fn fn, void *data)
3012{
3013 int r = 0;
3014 struct cache *cache = ti->private;
3015
3016 r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data);
3017 if (!r)
3018 r = fn(ti, cache->origin_dev, 0, ti->len, data);
3019
3020 return r;
3021}
3022
3023/*
3024 * We assume I/O is going to the origin (which is the volume
3025 * more likely to have restrictions e.g. by being striped).
3026 * (Looking up the exact location of the data would be expensive
3027 * and could always be out of date by the time the bio is submitted.)
3028 */
3029static int cache_bvec_merge(struct dm_target *ti,
3030 struct bvec_merge_data *bvm,
3031 struct bio_vec *biovec, int max_size)
3032{
3033 struct cache *cache = ti->private;
3034 struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev);
3035
3036 if (!q->merge_bvec_fn)
3037 return max_size;
3038
3039 bvm->bi_bdev = cache->origin_dev->bdev;
3040 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3041}
3042
3043static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
3044{
3045 /*
3046 * FIXME: these limits may be incompatible with the cache device
3047 */
Heinz Mauelshagen64ab3462014-03-27 15:14:10 -04003048 limits->max_discard_sectors = cache->sectors_per_block;
3049 limits->discard_granularity = cache->sectors_per_block << SECTOR_SHIFT;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003050}
3051
3052static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
3053{
3054 struct cache *cache = ti->private;
Mike Snitzerf6109372013-08-20 15:02:41 -04003055 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003056
Mike Snitzerf6109372013-08-20 15:02:41 -04003057 /*
3058 * If the system-determined stacked limits are compatible with the
3059 * cache's blocksize (io_opt is a factor) do not override them.
3060 */
3061 if (io_opt_sectors < cache->sectors_per_block ||
3062 do_div(io_opt_sectors, cache->sectors_per_block)) {
3063 blk_limits_io_min(limits, 0);
3064 blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
3065 }
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003066 set_discard_limits(cache, limits);
3067}
3068
3069/*----------------------------------------------------------------*/
3070
3071static struct target_type cache_target = {
3072 .name = "cache",
Joe Thornber05966612014-04-03 16:16:44 +01003073 .version = {1, 4, 0},
Joe Thornberc6b4fcb2013-03-01 22:45:51 +00003074 .module = THIS_MODULE,
3075 .ctr = cache_ctr,
3076 .dtr = cache_dtr,
3077 .map = cache_map,
3078 .end_io = cache_end_io,
3079 .postsuspend = cache_postsuspend,
3080 .preresume = cache_preresume,
3081 .resume = cache_resume,
3082 .status = cache_status,
3083 .message = cache_message,
3084 .iterate_devices = cache_iterate_devices,
3085 .merge = cache_bvec_merge,
3086 .io_hints = cache_io_hints,
3087};
3088
3089static int __init dm_cache_init(void)
3090{
3091 int r;
3092
3093 r = dm_register_target(&cache_target);
3094 if (r) {
3095 DMERR("cache target registration failed: %d", r);
3096 return r;
3097 }
3098
3099 migration_cache = KMEM_CACHE(dm_cache_migration, 0);
3100 if (!migration_cache) {
3101 dm_unregister_target(&cache_target);
3102 return -ENOMEM;
3103 }
3104
3105 return 0;
3106}
3107
3108static void __exit dm_cache_exit(void)
3109{
3110 dm_unregister_target(&cache_target);
3111 kmem_cache_destroy(migration_cache);
3112}
3113
3114module_init(dm_cache_init);
3115module_exit(dm_cache_exit);
3116
3117MODULE_DESCRIPTION(DM_NAME " cache target");
3118MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
3119MODULE_LICENSE("GPL");