2 * Copyright (C) 2012 Red Hat. All rights reserved.
4 * This file is released under the GPL.
8 #include "dm-bio-prison.h"
9 #include "dm-bio-record.h"
10 #include "dm-cache-metadata.h"
12 #include <linux/dm-io.h>
13 #include <linux/dm-kcopyd.h>
14 #include <linux/jiffies.h>
15 #include <linux/init.h>
16 #include <linux/mempool.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/vmalloc.h>
21 #define DM_MSG_PREFIX "cache"
23 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle
,
24 "A percentage of time allocated for copying to and/or from cache");
26 /*----------------------------------------------------------------*/
28 #define IOT_RESOLUTION 4
34 * Sectors of in-flight IO.
39 * The time, in jiffies, when this device became idle (if it is
42 unsigned long idle_time
;
43 unsigned long last_update_time
;
46 static void iot_init(struct io_tracker
*iot
)
48 spin_lock_init(&iot
->lock
);
51 iot
->last_update_time
= jiffies
;
54 static bool __iot_idle_for(struct io_tracker
*iot
, unsigned long jifs
)
59 return time_after(jiffies
, iot
->idle_time
+ jifs
);
62 static bool iot_idle_for(struct io_tracker
*iot
, unsigned long jifs
)
67 spin_lock_irqsave(&iot
->lock
, flags
);
68 r
= __iot_idle_for(iot
, jifs
);
69 spin_unlock_irqrestore(&iot
->lock
, flags
);
74 static void iot_io_begin(struct io_tracker
*iot
, sector_t len
)
78 spin_lock_irqsave(&iot
->lock
, flags
);
79 iot
->in_flight
+= len
;
80 spin_unlock_irqrestore(&iot
->lock
, flags
);
83 static void __iot_io_end(struct io_tracker
*iot
, sector_t len
)
85 iot
->in_flight
-= len
;
87 iot
->idle_time
= jiffies
;
90 static void iot_io_end(struct io_tracker
*iot
, sector_t len
)
94 spin_lock_irqsave(&iot
->lock
, flags
);
95 __iot_io_end(iot
, len
);
96 spin_unlock_irqrestore(&iot
->lock
, flags
);
99 /*----------------------------------------------------------------*/
104 * oblock: index of an origin block
105 * cblock: index of a cache block
106 * promotion: movement of a block from origin to cache
107 * demotion: movement of a block from cache to origin
108 * migration: movement of a block between the origin and cache device,
112 /*----------------------------------------------------------------*/
115 * There are a couple of places where we let a bio run, but want to do some
116 * work before calling its endio function. We do this by temporarily
117 * changing the endio fn.
119 struct dm_hook_info
{
120 bio_end_io_t
*bi_end_io
;
123 static void dm_hook_bio(struct dm_hook_info
*h
, struct bio
*bio
,
124 bio_end_io_t
*bi_end_io
, void *bi_private
)
126 h
->bi_end_io
= bio
->bi_end_io
;
128 bio
->bi_end_io
= bi_end_io
;
129 bio
->bi_private
= bi_private
;
132 static void dm_unhook_bio(struct dm_hook_info
*h
, struct bio
*bio
)
134 bio
->bi_end_io
= h
->bi_end_io
;
137 /*----------------------------------------------------------------*/
139 #define MIGRATION_POOL_SIZE 128
140 #define COMMIT_PERIOD HZ
141 #define MIGRATION_COUNT_WINDOW 10
144 * The block size of the device holding cache data must be
145 * between 32KB and 1GB.
147 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT)
148 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
150 enum cache_metadata_mode
{
151 CM_WRITE
, /* metadata may be changed */
152 CM_READ_ONLY
, /* metadata may not be changed */
158 * Data is written to cached blocks only. These blocks are marked
159 * dirty. If you lose the cache device you will lose data.
160 * Potential performance increase for both reads and writes.
165 * Data is written to both cache and origin. Blocks are never
166 * dirty. Potential performance benfit for reads only.
171 * A degraded mode useful for various cache coherency situations
172 * (eg, rolling back snapshots). Reads and writes always go to the
173 * origin. If a write goes to a cached oblock, then the cache
174 * block is invalidated.
179 struct cache_features
{
180 enum cache_metadata_mode mode
;
181 enum cache_io_mode io_mode
;
191 atomic_t copies_avoided
;
192 atomic_t cache_cell_clash
;
193 atomic_t commit_count
;
194 atomic_t discard_count
;
198 * Defines a range of cblocks, begin to (end - 1) are in the range. end is
199 * the one-past-the-end value.
201 struct cblock_range
{
206 struct invalidation_request
{
207 struct list_head list
;
208 struct cblock_range
*cblocks
;
213 wait_queue_head_t result_wait
;
217 struct dm_target
*ti
;
218 struct dm_target_callbacks callbacks
;
220 struct dm_cache_metadata
*cmd
;
223 * Metadata is written to this device.
225 struct dm_dev
*metadata_dev
;
228 * The slower of the two data devices. Typically a spindle.
230 struct dm_dev
*origin_dev
;
233 * The faster of the two data devices. Typically an SSD.
235 struct dm_dev
*cache_dev
;
238 * Size of the origin device in _complete_ blocks and native sectors.
240 dm_oblock_t origin_blocks
;
241 sector_t origin_sectors
;
244 * Size of the cache device in blocks.
246 dm_cblock_t cache_size
;
249 * Fields for converting from sectors to blocks.
251 uint32_t sectors_per_block
;
252 int sectors_per_block_shift
;
255 struct list_head deferred_cells
;
256 struct bio_list deferred_bios
;
257 struct bio_list deferred_flush_bios
;
258 struct bio_list deferred_writethrough_bios
;
259 struct list_head quiesced_migrations
;
260 struct list_head completed_migrations
;
261 struct list_head need_commit_migrations
;
262 sector_t migration_threshold
;
263 wait_queue_head_t migration_wait
;
264 atomic_t nr_allocated_migrations
;
267 * The number of in flight migrations that are performing
268 * background io. eg, promotion, writeback.
270 atomic_t nr_io_migrations
;
272 wait_queue_head_t quiescing_wait
;
274 atomic_t quiescing_ack
;
277 * cache_size entries, dirty if set
280 unsigned long *dirty_bitset
;
283 * origin_blocks entries, discarded if set.
285 dm_dblock_t discard_nr_blocks
;
286 unsigned long *discard_bitset
;
287 uint32_t discard_block_size
; /* a power of 2 times sectors per block */
290 * Rather than reconstructing the table line for the status we just
291 * save it and regurgitate.
293 unsigned nr_ctr_args
;
294 const char **ctr_args
;
296 struct dm_kcopyd_client
*copier
;
297 struct workqueue_struct
*wq
;
298 struct work_struct worker
;
300 struct delayed_work waker
;
301 unsigned long last_commit_jiffies
;
303 struct dm_bio_prison
*prison
;
304 struct dm_deferred_set
*all_io_ds
;
306 mempool_t
*migration_pool
;
308 struct dm_cache_policy
*policy
;
309 unsigned policy_nr_args
;
311 bool need_tick_bio
:1;
314 bool commit_requested
:1;
315 bool loaded_mappings
:1;
316 bool loaded_discards
:1;
319 * Cache features such as write-through.
321 struct cache_features features
;
323 struct cache_stats stats
;
326 * Invalidation fields.
328 spinlock_t invalidation_lock
;
329 struct list_head invalidation_requests
;
331 struct io_tracker origin_tracker
;
334 struct per_bio_data
{
337 struct dm_deferred_entry
*all_io_entry
;
338 struct dm_hook_info hook_info
;
342 * writethrough fields. These MUST remain at the end of this
343 * structure and the 'cache' member must be the first as it
344 * is used to determine the offset of the writethrough fields.
348 struct dm_bio_details bio_details
;
351 struct dm_cache_migration
{
352 struct list_head list
;
355 unsigned long start_jiffies
;
356 dm_oblock_t old_oblock
;
357 dm_oblock_t new_oblock
;
365 bool requeue_holder
:1;
368 struct dm_bio_prison_cell
*old_ocell
;
369 struct dm_bio_prison_cell
*new_ocell
;
373 * Processing a bio in the worker thread may require these memory
374 * allocations. We prealloc to avoid deadlocks (the same worker thread
375 * frees them back to the mempool).
378 struct dm_cache_migration
*mg
;
379 struct dm_bio_prison_cell
*cell1
;
380 struct dm_bio_prison_cell
*cell2
;
383 static enum cache_metadata_mode
get_cache_mode(struct cache
*cache
);
385 static void wake_worker(struct cache
*cache
)
387 queue_work(cache
->wq
, &cache
->worker
);
390 /*----------------------------------------------------------------*/
392 static struct dm_bio_prison_cell
*alloc_prison_cell(struct cache
*cache
)
394 /* FIXME: change to use a local slab. */
395 return dm_bio_prison_alloc_cell(cache
->prison
, GFP_NOWAIT
);
398 static void free_prison_cell(struct cache
*cache
, struct dm_bio_prison_cell
*cell
)
400 dm_bio_prison_free_cell(cache
->prison
, cell
);
403 static struct dm_cache_migration
*alloc_migration(struct cache
*cache
)
405 struct dm_cache_migration
*mg
;
407 mg
= mempool_alloc(cache
->migration_pool
, GFP_NOWAIT
);
410 atomic_inc(&mg
->cache
->nr_allocated_migrations
);
416 static void free_migration(struct dm_cache_migration
*mg
)
418 struct cache
*cache
= mg
->cache
;
420 if (atomic_dec_and_test(&cache
->nr_allocated_migrations
))
421 wake_up(&cache
->migration_wait
);
423 mempool_free(mg
, cache
->migration_pool
);
426 static int prealloc_data_structs(struct cache
*cache
, struct prealloc
*p
)
429 p
->mg
= alloc_migration(cache
);
435 p
->cell1
= alloc_prison_cell(cache
);
441 p
->cell2
= alloc_prison_cell(cache
);
449 static void prealloc_free_structs(struct cache
*cache
, struct prealloc
*p
)
452 free_prison_cell(cache
, p
->cell2
);
455 free_prison_cell(cache
, p
->cell1
);
458 free_migration(p
->mg
);
461 static struct dm_cache_migration
*prealloc_get_migration(struct prealloc
*p
)
463 struct dm_cache_migration
*mg
= p
->mg
;
472 * You must have a cell within the prealloc struct to return. If not this
473 * function will BUG() rather than returning NULL.
475 static struct dm_bio_prison_cell
*prealloc_get_cell(struct prealloc
*p
)
477 struct dm_bio_prison_cell
*r
= NULL
;
483 } else if (p
->cell2
) {
493 * You can't have more than two cells in a prealloc struct. BUG() will be
494 * called if you try and overfill.
496 static void prealloc_put_cell(struct prealloc
*p
, struct dm_bio_prison_cell
*cell
)
508 /*----------------------------------------------------------------*/
510 static void build_key(dm_oblock_t begin
, dm_oblock_t end
, struct dm_cell_key
*key
)
514 key
->block_begin
= from_oblock(begin
);
515 key
->block_end
= from_oblock(end
);
519 * The caller hands in a preallocated cell, and a free function for it.
520 * The cell will be freed if there's an error, or if it wasn't used because
521 * a cell with that key already exists.
523 typedef void (*cell_free_fn
)(void *context
, struct dm_bio_prison_cell
*cell
);
525 static int bio_detain_range(struct cache
*cache
, dm_oblock_t oblock_begin
, dm_oblock_t oblock_end
,
526 struct bio
*bio
, struct dm_bio_prison_cell
*cell_prealloc
,
527 cell_free_fn free_fn
, void *free_context
,
528 struct dm_bio_prison_cell
**cell_result
)
531 struct dm_cell_key key
;
533 build_key(oblock_begin
, oblock_end
, &key
);
534 r
= dm_bio_detain(cache
->prison
, &key
, bio
, cell_prealloc
, cell_result
);
536 free_fn(free_context
, cell_prealloc
);
541 static int bio_detain(struct cache
*cache
, dm_oblock_t oblock
,
542 struct bio
*bio
, struct dm_bio_prison_cell
*cell_prealloc
,
543 cell_free_fn free_fn
, void *free_context
,
544 struct dm_bio_prison_cell
**cell_result
)
546 dm_oblock_t end
= to_oblock(from_oblock(oblock
) + 1ULL);
547 return bio_detain_range(cache
, oblock
, end
, bio
,
548 cell_prealloc
, free_fn
, free_context
, cell_result
);
551 static int get_cell(struct cache
*cache
,
553 struct prealloc
*structs
,
554 struct dm_bio_prison_cell
**cell_result
)
557 struct dm_cell_key key
;
558 struct dm_bio_prison_cell
*cell_prealloc
;
560 cell_prealloc
= prealloc_get_cell(structs
);
562 build_key(oblock
, to_oblock(from_oblock(oblock
) + 1ULL), &key
);
563 r
= dm_get_cell(cache
->prison
, &key
, cell_prealloc
, cell_result
);
565 prealloc_put_cell(structs
, cell_prealloc
);
570 /*----------------------------------------------------------------*/
572 static bool is_dirty(struct cache
*cache
, dm_cblock_t b
)
574 return test_bit(from_cblock(b
), cache
->dirty_bitset
);
577 static void set_dirty(struct cache
*cache
, dm_oblock_t oblock
, dm_cblock_t cblock
)
579 if (!test_and_set_bit(from_cblock(cblock
), cache
->dirty_bitset
)) {
580 atomic_inc(&cache
->nr_dirty
);
581 policy_set_dirty(cache
->policy
, oblock
);
585 static void clear_dirty(struct cache
*cache
, dm_oblock_t oblock
, dm_cblock_t cblock
)
587 if (test_and_clear_bit(from_cblock(cblock
), cache
->dirty_bitset
)) {
588 policy_clear_dirty(cache
->policy
, oblock
);
589 if (atomic_dec_return(&cache
->nr_dirty
) == 0)
590 dm_table_event(cache
->ti
->table
);
594 /*----------------------------------------------------------------*/
596 static bool block_size_is_power_of_two(struct cache
*cache
)
598 return cache
->sectors_per_block_shift
>= 0;
601 /* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */
602 #if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6
605 static dm_block_t
block_div(dm_block_t b
, uint32_t n
)
612 static dm_block_t
oblocks_per_dblock(struct cache
*cache
)
614 dm_block_t oblocks
= cache
->discard_block_size
;
616 if (block_size_is_power_of_two(cache
))
617 oblocks
>>= cache
->sectors_per_block_shift
;
619 oblocks
= block_div(oblocks
, cache
->sectors_per_block
);
624 static dm_dblock_t
oblock_to_dblock(struct cache
*cache
, dm_oblock_t oblock
)
626 return to_dblock(block_div(from_oblock(oblock
),
627 oblocks_per_dblock(cache
)));
630 static dm_oblock_t
dblock_to_oblock(struct cache
*cache
, dm_dblock_t dblock
)
632 return to_oblock(from_dblock(dblock
) * oblocks_per_dblock(cache
));
635 static void set_discard(struct cache
*cache
, dm_dblock_t b
)
639 BUG_ON(from_dblock(b
) >= from_dblock(cache
->discard_nr_blocks
));
640 atomic_inc(&cache
->stats
.discard_count
);
642 spin_lock_irqsave(&cache
->lock
, flags
);
643 set_bit(from_dblock(b
), cache
->discard_bitset
);
644 spin_unlock_irqrestore(&cache
->lock
, flags
);
647 static void clear_discard(struct cache
*cache
, dm_dblock_t b
)
651 spin_lock_irqsave(&cache
->lock
, flags
);
652 clear_bit(from_dblock(b
), cache
->discard_bitset
);
653 spin_unlock_irqrestore(&cache
->lock
, flags
);
656 static bool is_discarded(struct cache
*cache
, dm_dblock_t b
)
661 spin_lock_irqsave(&cache
->lock
, flags
);
662 r
= test_bit(from_dblock(b
), cache
->discard_bitset
);
663 spin_unlock_irqrestore(&cache
->lock
, flags
);
668 static bool is_discarded_oblock(struct cache
*cache
, dm_oblock_t b
)
673 spin_lock_irqsave(&cache
->lock
, flags
);
674 r
= test_bit(from_dblock(oblock_to_dblock(cache
, b
)),
675 cache
->discard_bitset
);
676 spin_unlock_irqrestore(&cache
->lock
, flags
);
681 /*----------------------------------------------------------------*/
683 static void load_stats(struct cache
*cache
)
685 struct dm_cache_statistics stats
;
687 dm_cache_metadata_get_stats(cache
->cmd
, &stats
);
688 atomic_set(&cache
->stats
.read_hit
, stats
.read_hits
);
689 atomic_set(&cache
->stats
.read_miss
, stats
.read_misses
);
690 atomic_set(&cache
->stats
.write_hit
, stats
.write_hits
);
691 atomic_set(&cache
->stats
.write_miss
, stats
.write_misses
);
694 static void save_stats(struct cache
*cache
)
696 struct dm_cache_statistics stats
;
698 if (get_cache_mode(cache
) >= CM_READ_ONLY
)
701 stats
.read_hits
= atomic_read(&cache
->stats
.read_hit
);
702 stats
.read_misses
= atomic_read(&cache
->stats
.read_miss
);
703 stats
.write_hits
= atomic_read(&cache
->stats
.write_hit
);
704 stats
.write_misses
= atomic_read(&cache
->stats
.write_miss
);
706 dm_cache_metadata_set_stats(cache
->cmd
, &stats
);
709 /*----------------------------------------------------------------
711 *--------------------------------------------------------------*/
714 * If using writeback, leave out struct per_bio_data's writethrough fields.
716 #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache))
717 #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data))
719 static bool writethrough_mode(struct cache_features
*f
)
721 return f
->io_mode
== CM_IO_WRITETHROUGH
;
724 static bool writeback_mode(struct cache_features
*f
)
726 return f
->io_mode
== CM_IO_WRITEBACK
;
729 static bool passthrough_mode(struct cache_features
*f
)
731 return f
->io_mode
== CM_IO_PASSTHROUGH
;
734 static size_t get_per_bio_data_size(struct cache
*cache
)
736 return writethrough_mode(&cache
->features
) ? PB_DATA_SIZE_WT
: PB_DATA_SIZE_WB
;
739 static struct per_bio_data
*get_per_bio_data(struct bio
*bio
, size_t data_size
)
741 struct per_bio_data
*pb
= dm_per_bio_data(bio
, data_size
);
746 static struct per_bio_data
*init_per_bio_data(struct bio
*bio
, size_t data_size
)
748 struct per_bio_data
*pb
= get_per_bio_data(bio
, data_size
);
751 pb
->req_nr
= dm_bio_get_target_bio_nr(bio
);
752 pb
->all_io_entry
= NULL
;
758 /*----------------------------------------------------------------
760 *--------------------------------------------------------------*/
761 static void remap_to_origin(struct cache
*cache
, struct bio
*bio
)
763 bio
->bi_bdev
= cache
->origin_dev
->bdev
;
766 static void remap_to_cache(struct cache
*cache
, struct bio
*bio
,
769 sector_t bi_sector
= bio
->bi_iter
.bi_sector
;
770 sector_t block
= from_cblock(cblock
);
772 bio
->bi_bdev
= cache
->cache_dev
->bdev
;
773 if (!block_size_is_power_of_two(cache
))
774 bio
->bi_iter
.bi_sector
=
775 (block
* cache
->sectors_per_block
) +
776 sector_div(bi_sector
, cache
->sectors_per_block
);
778 bio
->bi_iter
.bi_sector
=
779 (block
<< cache
->sectors_per_block_shift
) |
780 (bi_sector
& (cache
->sectors_per_block
- 1));
783 static void check_if_tick_bio_needed(struct cache
*cache
, struct bio
*bio
)
786 size_t pb_data_size
= get_per_bio_data_size(cache
);
787 struct per_bio_data
*pb
= get_per_bio_data(bio
, pb_data_size
);
789 spin_lock_irqsave(&cache
->lock
, flags
);
790 if (cache
->need_tick_bio
&&
791 !(bio
->bi_rw
& (REQ_FUA
| REQ_FLUSH
| REQ_DISCARD
))) {
793 cache
->need_tick_bio
= false;
795 spin_unlock_irqrestore(&cache
->lock
, flags
);
798 static void remap_to_origin_clear_discard(struct cache
*cache
, struct bio
*bio
,
801 check_if_tick_bio_needed(cache
, bio
);
802 remap_to_origin(cache
, bio
);
803 if (bio_data_dir(bio
) == WRITE
)
804 clear_discard(cache
, oblock_to_dblock(cache
, oblock
));
807 static void remap_to_cache_dirty(struct cache
*cache
, struct bio
*bio
,
808 dm_oblock_t oblock
, dm_cblock_t cblock
)
810 check_if_tick_bio_needed(cache
, bio
);
811 remap_to_cache(cache
, bio
, cblock
);
812 if (bio_data_dir(bio
) == WRITE
) {
813 set_dirty(cache
, oblock
, cblock
);
814 clear_discard(cache
, oblock_to_dblock(cache
, oblock
));
818 static dm_oblock_t
get_bio_block(struct cache
*cache
, struct bio
*bio
)
820 sector_t block_nr
= bio
->bi_iter
.bi_sector
;
822 if (!block_size_is_power_of_two(cache
))
823 (void) sector_div(block_nr
, cache
->sectors_per_block
);
825 block_nr
>>= cache
->sectors_per_block_shift
;
827 return to_oblock(block_nr
);
830 static int bio_triggers_commit(struct cache
*cache
, struct bio
*bio
)
832 return bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
836 * You must increment the deferred set whilst the prison cell is held. To
837 * encourage this, we ask for 'cell' to be passed in.
839 static void inc_ds(struct cache
*cache
, struct bio
*bio
,
840 struct dm_bio_prison_cell
*cell
)
842 size_t pb_data_size
= get_per_bio_data_size(cache
);
843 struct per_bio_data
*pb
= get_per_bio_data(bio
, pb_data_size
);
846 BUG_ON(pb
->all_io_entry
);
848 pb
->all_io_entry
= dm_deferred_entry_inc(cache
->all_io_ds
);
851 static bool accountable_bio(struct cache
*cache
, struct bio
*bio
)
853 return ((bio
->bi_bdev
== cache
->origin_dev
->bdev
) &&
854 !(bio
->bi_rw
& REQ_DISCARD
));
857 static void accounted_begin(struct cache
*cache
, struct bio
*bio
)
859 size_t pb_data_size
= get_per_bio_data_size(cache
);
860 struct per_bio_data
*pb
= get_per_bio_data(bio
, pb_data_size
);
862 if (accountable_bio(cache
, bio
)) {
863 pb
->len
= bio_sectors(bio
);
864 iot_io_begin(&cache
->origin_tracker
, pb
->len
);
868 static void accounted_complete(struct cache
*cache
, struct bio
*bio
)
870 size_t pb_data_size
= get_per_bio_data_size(cache
);
871 struct per_bio_data
*pb
= get_per_bio_data(bio
, pb_data_size
);
873 iot_io_end(&cache
->origin_tracker
, pb
->len
);
876 static void accounted_request(struct cache
*cache
, struct bio
*bio
)
878 accounted_begin(cache
, bio
);
879 generic_make_request(bio
);
882 static void issue(struct cache
*cache
, struct bio
*bio
)
886 if (!bio_triggers_commit(cache
, bio
)) {
887 accounted_request(cache
, bio
);
892 * Batch together any bios that trigger commits and then issue a
893 * single commit for them in do_worker().
895 spin_lock_irqsave(&cache
->lock
, flags
);
896 cache
->commit_requested
= true;
897 bio_list_add(&cache
->deferred_flush_bios
, bio
);
898 spin_unlock_irqrestore(&cache
->lock
, flags
);
901 static void inc_and_issue(struct cache
*cache
, struct bio
*bio
, struct dm_bio_prison_cell
*cell
)
903 inc_ds(cache
, bio
, cell
);
907 static void defer_writethrough_bio(struct cache
*cache
, struct bio
*bio
)
911 spin_lock_irqsave(&cache
->lock
, flags
);
912 bio_list_add(&cache
->deferred_writethrough_bios
, bio
);
913 spin_unlock_irqrestore(&cache
->lock
, flags
);
918 static void writethrough_endio(struct bio
*bio
)
920 struct per_bio_data
*pb
= get_per_bio_data(bio
, PB_DATA_SIZE_WT
);
922 dm_unhook_bio(&pb
->hook_info
, bio
);
929 dm_bio_restore(&pb
->bio_details
, bio
);
930 remap_to_cache(pb
->cache
, bio
, pb
->cblock
);
933 * We can't issue this bio directly, since we're in interrupt
934 * context. So it gets put on a bio list for processing by the
937 defer_writethrough_bio(pb
->cache
, bio
);
941 * When running in writethrough mode we need to send writes to clean blocks
942 * to both the cache and origin devices. In future we'd like to clone the
943 * bio and send them in parallel, but for now we're doing them in
944 * series as this is easier.
946 static void remap_to_origin_then_cache(struct cache
*cache
, struct bio
*bio
,
947 dm_oblock_t oblock
, dm_cblock_t cblock
)
949 struct per_bio_data
*pb
= get_per_bio_data(bio
, PB_DATA_SIZE_WT
);
953 dm_hook_bio(&pb
->hook_info
, bio
, writethrough_endio
, NULL
);
954 dm_bio_record(&pb
->bio_details
, bio
);
956 remap_to_origin_clear_discard(pb
->cache
, bio
, oblock
);
959 /*----------------------------------------------------------------
961 *--------------------------------------------------------------*/
962 static enum cache_metadata_mode
get_cache_mode(struct cache
*cache
)
964 return cache
->features
.mode
;
967 static const char *cache_device_name(struct cache
*cache
)
969 return dm_device_name(dm_table_get_md(cache
->ti
->table
));
972 static void notify_mode_switch(struct cache
*cache
, enum cache_metadata_mode mode
)
974 const char *descs
[] = {
980 dm_table_event(cache
->ti
->table
);
981 DMINFO("%s: switching cache to %s mode",
982 cache_device_name(cache
), descs
[(int)mode
]);
985 static void set_cache_mode(struct cache
*cache
, enum cache_metadata_mode new_mode
)
988 enum cache_metadata_mode old_mode
= get_cache_mode(cache
);
990 if (dm_cache_metadata_needs_check(cache
->cmd
, &needs_check
)) {
991 DMERR("unable to read needs_check flag, setting failure mode");
995 if (new_mode
== CM_WRITE
&& needs_check
) {
996 DMERR("%s: unable to switch cache to write mode until repaired.",
997 cache_device_name(cache
));
998 if (old_mode
!= new_mode
)
1001 new_mode
= CM_READ_ONLY
;
1004 /* Never move out of fail mode */
1005 if (old_mode
== CM_FAIL
)
1011 dm_cache_metadata_set_read_only(cache
->cmd
);
1015 dm_cache_metadata_set_read_write(cache
->cmd
);
1019 cache
->features
.mode
= new_mode
;
1021 if (new_mode
!= old_mode
)
1022 notify_mode_switch(cache
, new_mode
);
1025 static void abort_transaction(struct cache
*cache
)
1027 const char *dev_name
= cache_device_name(cache
);
1029 if (get_cache_mode(cache
) >= CM_READ_ONLY
)
1032 if (dm_cache_metadata_set_needs_check(cache
->cmd
)) {
1033 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name
);
1034 set_cache_mode(cache
, CM_FAIL
);
1037 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name
);
1038 if (dm_cache_metadata_abort(cache
->cmd
)) {
1039 DMERR("%s: failed to abort metadata transaction", dev_name
);
1040 set_cache_mode(cache
, CM_FAIL
);
1044 static void metadata_operation_failed(struct cache
*cache
, const char *op
, int r
)
1046 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
1047 cache_device_name(cache
), op
, r
);
1048 abort_transaction(cache
);
1049 set_cache_mode(cache
, CM_READ_ONLY
);
1052 /*----------------------------------------------------------------
1053 * Migration processing
1055 * Migration covers moving data from the origin device to the cache, or
1057 *--------------------------------------------------------------*/
1058 static void inc_io_migrations(struct cache
*cache
)
1060 atomic_inc(&cache
->nr_io_migrations
);
1063 static void dec_io_migrations(struct cache
*cache
)
1065 atomic_dec(&cache
->nr_io_migrations
);
1068 static bool discard_or_flush(struct bio
*bio
)
1070 return bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
| REQ_DISCARD
);
1073 static void __cell_defer(struct cache
*cache
, struct dm_bio_prison_cell
*cell
)
1075 if (discard_or_flush(cell
->holder
)) {
1077 * We have to handle these bios individually.
1079 dm_cell_release(cache
->prison
, cell
, &cache
->deferred_bios
);
1080 free_prison_cell(cache
, cell
);
1082 list_add_tail(&cell
->user_list
, &cache
->deferred_cells
);
1085 static void cell_defer(struct cache
*cache
, struct dm_bio_prison_cell
*cell
, bool holder
)
1087 unsigned long flags
;
1089 if (!holder
&& dm_cell_promote_or_release(cache
->prison
, cell
)) {
1091 * There was no prisoner to promote to holder, the
1092 * cell has been released.
1094 free_prison_cell(cache
, cell
);
1098 spin_lock_irqsave(&cache
->lock
, flags
);
1099 __cell_defer(cache
, cell
);
1100 spin_unlock_irqrestore(&cache
->lock
, flags
);
1105 static void cell_error_with_code(struct cache
*cache
, struct dm_bio_prison_cell
*cell
, int err
)
1107 dm_cell_error(cache
->prison
, cell
, err
);
1108 free_prison_cell(cache
, cell
);
1111 static void cell_requeue(struct cache
*cache
, struct dm_bio_prison_cell
*cell
)
1113 cell_error_with_code(cache
, cell
, DM_ENDIO_REQUEUE
);
1116 static void free_io_migration(struct dm_cache_migration
*mg
)
1118 struct cache
*cache
= mg
->cache
;
1120 dec_io_migrations(cache
);
1125 static void migration_failure(struct dm_cache_migration
*mg
)
1127 struct cache
*cache
= mg
->cache
;
1128 const char *dev_name
= cache_device_name(cache
);
1130 if (mg
->writeback
) {
1131 DMERR_LIMIT("%s: writeback failed; couldn't copy block", dev_name
);
1132 set_dirty(cache
, mg
->old_oblock
, mg
->cblock
);
1133 cell_defer(cache
, mg
->old_ocell
, false);
1135 } else if (mg
->demote
) {
1136 DMERR_LIMIT("%s: demotion failed; couldn't copy block", dev_name
);
1137 policy_force_mapping(cache
->policy
, mg
->new_oblock
, mg
->old_oblock
);
1139 cell_defer(cache
, mg
->old_ocell
, mg
->promote
? false : true);
1141 cell_defer(cache
, mg
->new_ocell
, true);
1143 DMERR_LIMIT("%s: promotion failed; couldn't copy block", dev_name
);
1144 policy_remove_mapping(cache
->policy
, mg
->new_oblock
);
1145 cell_defer(cache
, mg
->new_ocell
, true);
1148 free_io_migration(mg
);
1151 static void migration_success_pre_commit(struct dm_cache_migration
*mg
)
1154 unsigned long flags
;
1155 struct cache
*cache
= mg
->cache
;
1157 if (mg
->writeback
) {
1158 clear_dirty(cache
, mg
->old_oblock
, mg
->cblock
);
1159 cell_defer(cache
, mg
->old_ocell
, false);
1160 free_io_migration(mg
);
1163 } else if (mg
->demote
) {
1164 r
= dm_cache_remove_mapping(cache
->cmd
, mg
->cblock
);
1166 DMERR_LIMIT("%s: demotion failed; couldn't update on disk metadata",
1167 cache_device_name(cache
));
1168 metadata_operation_failed(cache
, "dm_cache_remove_mapping", r
);
1169 policy_force_mapping(cache
->policy
, mg
->new_oblock
,
1172 cell_defer(cache
, mg
->new_ocell
, true);
1173 free_io_migration(mg
);
1177 r
= dm_cache_insert_mapping(cache
->cmd
, mg
->cblock
, mg
->new_oblock
);
1179 DMERR_LIMIT("%s: promotion failed; couldn't update on disk metadata",
1180 cache_device_name(cache
));
1181 metadata_operation_failed(cache
, "dm_cache_insert_mapping", r
);
1182 policy_remove_mapping(cache
->policy
, mg
->new_oblock
);
1183 free_io_migration(mg
);
1188 spin_lock_irqsave(&cache
->lock
, flags
);
1189 list_add_tail(&mg
->list
, &cache
->need_commit_migrations
);
1190 cache
->commit_requested
= true;
1191 spin_unlock_irqrestore(&cache
->lock
, flags
);
1194 static void migration_success_post_commit(struct dm_cache_migration
*mg
)
1196 unsigned long flags
;
1197 struct cache
*cache
= mg
->cache
;
1199 if (mg
->writeback
) {
1200 DMWARN_LIMIT("%s: writeback unexpectedly triggered commit",
1201 cache_device_name(cache
));
1204 } else if (mg
->demote
) {
1205 cell_defer(cache
, mg
->old_ocell
, mg
->promote
? false : true);
1210 spin_lock_irqsave(&cache
->lock
, flags
);
1211 list_add_tail(&mg
->list
, &cache
->quiesced_migrations
);
1212 spin_unlock_irqrestore(&cache
->lock
, flags
);
1216 policy_remove_mapping(cache
->policy
, mg
->old_oblock
);
1217 free_io_migration(mg
);
1221 if (mg
->requeue_holder
) {
1222 clear_dirty(cache
, mg
->new_oblock
, mg
->cblock
);
1223 cell_defer(cache
, mg
->new_ocell
, true);
1226 * The block was promoted via an overwrite, so it's dirty.
1228 set_dirty(cache
, mg
->new_oblock
, mg
->cblock
);
1229 bio_endio(mg
->new_ocell
->holder
);
1230 cell_defer(cache
, mg
->new_ocell
, false);
1232 free_io_migration(mg
);
1236 static void copy_complete(int read_err
, unsigned long write_err
, void *context
)
1238 unsigned long flags
;
1239 struct dm_cache_migration
*mg
= (struct dm_cache_migration
*) context
;
1240 struct cache
*cache
= mg
->cache
;
1242 if (read_err
|| write_err
)
1245 spin_lock_irqsave(&cache
->lock
, flags
);
1246 list_add_tail(&mg
->list
, &cache
->completed_migrations
);
1247 spin_unlock_irqrestore(&cache
->lock
, flags
);
1252 static void issue_copy(struct dm_cache_migration
*mg
)
1255 struct dm_io_region o_region
, c_region
;
1256 struct cache
*cache
= mg
->cache
;
1257 sector_t cblock
= from_cblock(mg
->cblock
);
1259 o_region
.bdev
= cache
->origin_dev
->bdev
;
1260 o_region
.count
= cache
->sectors_per_block
;
1262 c_region
.bdev
= cache
->cache_dev
->bdev
;
1263 c_region
.sector
= cblock
* cache
->sectors_per_block
;
1264 c_region
.count
= cache
->sectors_per_block
;
1266 if (mg
->writeback
|| mg
->demote
) {
1268 o_region
.sector
= from_oblock(mg
->old_oblock
) * cache
->sectors_per_block
;
1269 r
= dm_kcopyd_copy(cache
->copier
, &c_region
, 1, &o_region
, 0, copy_complete
, mg
);
1272 o_region
.sector
= from_oblock(mg
->new_oblock
) * cache
->sectors_per_block
;
1273 r
= dm_kcopyd_copy(cache
->copier
, &o_region
, 1, &c_region
, 0, copy_complete
, mg
);
1277 DMERR_LIMIT("%s: issuing migration failed", cache_device_name(cache
));
1278 migration_failure(mg
);
1282 static void overwrite_endio(struct bio
*bio
)
1284 struct dm_cache_migration
*mg
= bio
->bi_private
;
1285 struct cache
*cache
= mg
->cache
;
1286 size_t pb_data_size
= get_per_bio_data_size(cache
);
1287 struct per_bio_data
*pb
= get_per_bio_data(bio
, pb_data_size
);
1288 unsigned long flags
;
1290 dm_unhook_bio(&pb
->hook_info
, bio
);
1295 mg
->requeue_holder
= false;
1297 spin_lock_irqsave(&cache
->lock
, flags
);
1298 list_add_tail(&mg
->list
, &cache
->completed_migrations
);
1299 spin_unlock_irqrestore(&cache
->lock
, flags
);
1304 static void issue_overwrite(struct dm_cache_migration
*mg
, struct bio
*bio
)
1306 size_t pb_data_size
= get_per_bio_data_size(mg
->cache
);
1307 struct per_bio_data
*pb
= get_per_bio_data(bio
, pb_data_size
);
1309 dm_hook_bio(&pb
->hook_info
, bio
, overwrite_endio
, mg
);
1310 remap_to_cache_dirty(mg
->cache
, bio
, mg
->new_oblock
, mg
->cblock
);
1313 * No need to inc_ds() here, since the cell will be held for the
1314 * duration of the io.
1316 accounted_request(mg
->cache
, bio
);
1319 static bool bio_writes_complete_block(struct cache
*cache
, struct bio
*bio
)
1321 return (bio_data_dir(bio
) == WRITE
) &&
1322 (bio
->bi_iter
.bi_size
== (cache
->sectors_per_block
<< SECTOR_SHIFT
));
1325 static void avoid_copy(struct dm_cache_migration
*mg
)
1327 atomic_inc(&mg
->cache
->stats
.copies_avoided
);
1328 migration_success_pre_commit(mg
);
1331 static void calc_discard_block_range(struct cache
*cache
, struct bio
*bio
,
1332 dm_dblock_t
*b
, dm_dblock_t
*e
)
1334 sector_t sb
= bio
->bi_iter
.bi_sector
;
1335 sector_t se
= bio_end_sector(bio
);
1337 *b
= to_dblock(dm_sector_div_up(sb
, cache
->discard_block_size
));
1339 if (se
- sb
< cache
->discard_block_size
)
1342 *e
= to_dblock(block_div(se
, cache
->discard_block_size
));
1345 static void issue_discard(struct dm_cache_migration
*mg
)
1348 struct bio
*bio
= mg
->new_ocell
->holder
;
1349 struct cache
*cache
= mg
->cache
;
1351 calc_discard_block_range(cache
, bio
, &b
, &e
);
1353 set_discard(cache
, b
);
1354 b
= to_dblock(from_dblock(b
) + 1);
1358 cell_defer(cache
, mg
->new_ocell
, false);
1363 static void issue_copy_or_discard(struct dm_cache_migration
*mg
)
1366 struct cache
*cache
= mg
->cache
;
1373 if (mg
->writeback
|| mg
->demote
)
1374 avoid
= !is_dirty(cache
, mg
->cblock
) ||
1375 is_discarded_oblock(cache
, mg
->old_oblock
);
1377 struct bio
*bio
= mg
->new_ocell
->holder
;
1379 avoid
= is_discarded_oblock(cache
, mg
->new_oblock
);
1381 if (writeback_mode(&cache
->features
) &&
1382 !avoid
&& bio_writes_complete_block(cache
, bio
)) {
1383 issue_overwrite(mg
, bio
);
1388 avoid
? avoid_copy(mg
) : issue_copy(mg
);
1391 static void complete_migration(struct dm_cache_migration
*mg
)
1394 migration_failure(mg
);
1396 migration_success_pre_commit(mg
);
1399 static void process_migrations(struct cache
*cache
, struct list_head
*head
,
1400 void (*fn
)(struct dm_cache_migration
*))
1402 unsigned long flags
;
1403 struct list_head list
;
1404 struct dm_cache_migration
*mg
, *tmp
;
1406 INIT_LIST_HEAD(&list
);
1407 spin_lock_irqsave(&cache
->lock
, flags
);
1408 list_splice_init(head
, &list
);
1409 spin_unlock_irqrestore(&cache
->lock
, flags
);
1411 list_for_each_entry_safe(mg
, tmp
, &list
, list
)
1415 static void __queue_quiesced_migration(struct dm_cache_migration
*mg
)
1417 list_add_tail(&mg
->list
, &mg
->cache
->quiesced_migrations
);
1420 static void queue_quiesced_migration(struct dm_cache_migration
*mg
)
1422 unsigned long flags
;
1423 struct cache
*cache
= mg
->cache
;
1425 spin_lock_irqsave(&cache
->lock
, flags
);
1426 __queue_quiesced_migration(mg
);
1427 spin_unlock_irqrestore(&cache
->lock
, flags
);
1432 static void queue_quiesced_migrations(struct cache
*cache
, struct list_head
*work
)
1434 unsigned long flags
;
1435 struct dm_cache_migration
*mg
, *tmp
;
1437 spin_lock_irqsave(&cache
->lock
, flags
);
1438 list_for_each_entry_safe(mg
, tmp
, work
, list
)
1439 __queue_quiesced_migration(mg
);
1440 spin_unlock_irqrestore(&cache
->lock
, flags
);
1445 static void check_for_quiesced_migrations(struct cache
*cache
,
1446 struct per_bio_data
*pb
)
1448 struct list_head work
;
1450 if (!pb
->all_io_entry
)
1453 INIT_LIST_HEAD(&work
);
1454 dm_deferred_entry_dec(pb
->all_io_entry
, &work
);
1456 if (!list_empty(&work
))
1457 queue_quiesced_migrations(cache
, &work
);
1460 static void quiesce_migration(struct dm_cache_migration
*mg
)
1462 if (!dm_deferred_set_add_work(mg
->cache
->all_io_ds
, &mg
->list
))
1463 queue_quiesced_migration(mg
);
1466 static void promote(struct cache
*cache
, struct prealloc
*structs
,
1467 dm_oblock_t oblock
, dm_cblock_t cblock
,
1468 struct dm_bio_prison_cell
*cell
)
1470 struct dm_cache_migration
*mg
= prealloc_get_migration(structs
);
1473 mg
->discard
= false;
1474 mg
->writeback
= false;
1477 mg
->requeue_holder
= true;
1478 mg
->invalidate
= false;
1480 mg
->new_oblock
= oblock
;
1481 mg
->cblock
= cblock
;
1482 mg
->old_ocell
= NULL
;
1483 mg
->new_ocell
= cell
;
1484 mg
->start_jiffies
= jiffies
;
1486 inc_io_migrations(cache
);
1487 quiesce_migration(mg
);
1490 static void writeback(struct cache
*cache
, struct prealloc
*structs
,
1491 dm_oblock_t oblock
, dm_cblock_t cblock
,
1492 struct dm_bio_prison_cell
*cell
)
1494 struct dm_cache_migration
*mg
= prealloc_get_migration(structs
);
1497 mg
->discard
= false;
1498 mg
->writeback
= true;
1500 mg
->promote
= false;
1501 mg
->requeue_holder
= true;
1502 mg
->invalidate
= false;
1504 mg
->old_oblock
= oblock
;
1505 mg
->cblock
= cblock
;
1506 mg
->old_ocell
= cell
;
1507 mg
->new_ocell
= NULL
;
1508 mg
->start_jiffies
= jiffies
;
1510 inc_io_migrations(cache
);
1511 quiesce_migration(mg
);
1514 static void demote_then_promote(struct cache
*cache
, struct prealloc
*structs
,
1515 dm_oblock_t old_oblock
, dm_oblock_t new_oblock
,
1517 struct dm_bio_prison_cell
*old_ocell
,
1518 struct dm_bio_prison_cell
*new_ocell
)
1520 struct dm_cache_migration
*mg
= prealloc_get_migration(structs
);
1523 mg
->discard
= false;
1524 mg
->writeback
= false;
1527 mg
->requeue_holder
= true;
1528 mg
->invalidate
= false;
1530 mg
->old_oblock
= old_oblock
;
1531 mg
->new_oblock
= new_oblock
;
1532 mg
->cblock
= cblock
;
1533 mg
->old_ocell
= old_ocell
;
1534 mg
->new_ocell
= new_ocell
;
1535 mg
->start_jiffies
= jiffies
;
1537 inc_io_migrations(cache
);
1538 quiesce_migration(mg
);
1542 * Invalidate a cache entry. No writeback occurs; any changes in the cache
1543 * block are thrown away.
1545 static void invalidate(struct cache
*cache
, struct prealloc
*structs
,
1546 dm_oblock_t oblock
, dm_cblock_t cblock
,
1547 struct dm_bio_prison_cell
*cell
)
1549 struct dm_cache_migration
*mg
= prealloc_get_migration(structs
);
1552 mg
->discard
= false;
1553 mg
->writeback
= false;
1555 mg
->promote
= false;
1556 mg
->requeue_holder
= true;
1557 mg
->invalidate
= true;
1559 mg
->old_oblock
= oblock
;
1560 mg
->cblock
= cblock
;
1561 mg
->old_ocell
= cell
;
1562 mg
->new_ocell
= NULL
;
1563 mg
->start_jiffies
= jiffies
;
1565 inc_io_migrations(cache
);
1566 quiesce_migration(mg
);
1569 static void discard(struct cache
*cache
, struct prealloc
*structs
,
1570 struct dm_bio_prison_cell
*cell
)
1572 struct dm_cache_migration
*mg
= prealloc_get_migration(structs
);
1576 mg
->writeback
= false;
1578 mg
->promote
= false;
1579 mg
->requeue_holder
= false;
1580 mg
->invalidate
= false;
1582 mg
->old_ocell
= NULL
;
1583 mg
->new_ocell
= cell
;
1584 mg
->start_jiffies
= jiffies
;
1586 quiesce_migration(mg
);
1589 /*----------------------------------------------------------------
1591 *--------------------------------------------------------------*/
1592 static void defer_bio(struct cache
*cache
, struct bio
*bio
)
1594 unsigned long flags
;
1596 spin_lock_irqsave(&cache
->lock
, flags
);
1597 bio_list_add(&cache
->deferred_bios
, bio
);
1598 spin_unlock_irqrestore(&cache
->lock
, flags
);
1603 static void process_flush_bio(struct cache
*cache
, struct bio
*bio
)
1605 size_t pb_data_size
= get_per_bio_data_size(cache
);
1606 struct per_bio_data
*pb
= get_per_bio_data(bio
, pb_data_size
);
1608 BUG_ON(bio
->bi_iter
.bi_size
);
1610 remap_to_origin(cache
, bio
);
1612 remap_to_cache(cache
, bio
, 0);
1615 * REQ_FLUSH is not directed at any particular block so we don't
1616 * need to inc_ds(). REQ_FUA's are split into a write + REQ_FLUSH
1622 static void process_discard_bio(struct cache
*cache
, struct prealloc
*structs
,
1627 struct dm_bio_prison_cell
*cell_prealloc
, *new_ocell
;
1629 calc_discard_block_range(cache
, bio
, &b
, &e
);
1635 cell_prealloc
= prealloc_get_cell(structs
);
1636 r
= bio_detain_range(cache
, dblock_to_oblock(cache
, b
), dblock_to_oblock(cache
, e
), bio
, cell_prealloc
,
1637 (cell_free_fn
) prealloc_put_cell
,
1638 structs
, &new_ocell
);
1642 discard(cache
, structs
, new_ocell
);
1645 static bool spare_migration_bandwidth(struct cache
*cache
)
1647 sector_t current_volume
= (atomic_read(&cache
->nr_io_migrations
) + 1) *
1648 cache
->sectors_per_block
;
1649 return current_volume
< cache
->migration_threshold
;
1652 static void inc_hit_counter(struct cache
*cache
, struct bio
*bio
)
1654 atomic_inc(bio_data_dir(bio
) == READ
?
1655 &cache
->stats
.read_hit
: &cache
->stats
.write_hit
);
1658 static void inc_miss_counter(struct cache
*cache
, struct bio
*bio
)
1660 atomic_inc(bio_data_dir(bio
) == READ
?
1661 &cache
->stats
.read_miss
: &cache
->stats
.write_miss
);
1664 /*----------------------------------------------------------------*/
1667 struct cache
*cache
;
1668 struct bio_list bios_for_issue
;
1669 struct bio_list unhandled_bios
;
1673 static void inc_fn(void *context
, struct dm_bio_prison_cell
*cell
)
1676 struct inc_detail
*detail
= context
;
1677 struct cache
*cache
= detail
->cache
;
1679 inc_ds(cache
, cell
->holder
, cell
);
1680 if (bio_data_dir(cell
->holder
) == WRITE
)
1681 detail
->any_writes
= true;
1683 while ((bio
= bio_list_pop(&cell
->bios
))) {
1684 if (discard_or_flush(bio
)) {
1685 bio_list_add(&detail
->unhandled_bios
, bio
);
1689 if (bio_data_dir(bio
) == WRITE
)
1690 detail
->any_writes
= true;
1692 bio_list_add(&detail
->bios_for_issue
, bio
);
1693 inc_ds(cache
, bio
, cell
);
1697 // FIXME: refactor these two
1698 static void remap_cell_to_origin_clear_discard(struct cache
*cache
,
1699 struct dm_bio_prison_cell
*cell
,
1700 dm_oblock_t oblock
, bool issue_holder
)
1703 unsigned long flags
;
1704 struct inc_detail detail
;
1706 detail
.cache
= cache
;
1707 bio_list_init(&detail
.bios_for_issue
);
1708 bio_list_init(&detail
.unhandled_bios
);
1709 detail
.any_writes
= false;
1711 spin_lock_irqsave(&cache
->lock
, flags
);
1712 dm_cell_visit_release(cache
->prison
, inc_fn
, &detail
, cell
);
1713 bio_list_merge(&cache
->deferred_bios
, &detail
.unhandled_bios
);
1714 spin_unlock_irqrestore(&cache
->lock
, flags
);
1716 remap_to_origin(cache
, cell
->holder
);
1718 issue(cache
, cell
->holder
);
1720 accounted_begin(cache
, cell
->holder
);
1722 if (detail
.any_writes
)
1723 clear_discard(cache
, oblock_to_dblock(cache
, oblock
));
1725 while ((bio
= bio_list_pop(&detail
.bios_for_issue
))) {
1726 remap_to_origin(cache
, bio
);
1730 free_prison_cell(cache
, cell
);
1733 static void remap_cell_to_cache_dirty(struct cache
*cache
, struct dm_bio_prison_cell
*cell
,
1734 dm_oblock_t oblock
, dm_cblock_t cblock
, bool issue_holder
)
1737 unsigned long flags
;
1738 struct inc_detail detail
;
1740 detail
.cache
= cache
;
1741 bio_list_init(&detail
.bios_for_issue
);
1742 bio_list_init(&detail
.unhandled_bios
);
1743 detail
.any_writes
= false;
1745 spin_lock_irqsave(&cache
->lock
, flags
);
1746 dm_cell_visit_release(cache
->prison
, inc_fn
, &detail
, cell
);
1747 bio_list_merge(&cache
->deferred_bios
, &detail
.unhandled_bios
);
1748 spin_unlock_irqrestore(&cache
->lock
, flags
);
1750 remap_to_cache(cache
, cell
->holder
, cblock
);
1752 issue(cache
, cell
->holder
);
1754 accounted_begin(cache
, cell
->holder
);
1756 if (detail
.any_writes
) {
1757 set_dirty(cache
, oblock
, cblock
);
1758 clear_discard(cache
, oblock_to_dblock(cache
, oblock
));
1761 while ((bio
= bio_list_pop(&detail
.bios_for_issue
))) {
1762 remap_to_cache(cache
, bio
, cblock
);
1766 free_prison_cell(cache
, cell
);
1769 /*----------------------------------------------------------------*/
1771 struct old_oblock_lock
{
1772 struct policy_locker locker
;
1773 struct cache
*cache
;
1774 struct prealloc
*structs
;
1775 struct dm_bio_prison_cell
*cell
;
1778 static int null_locker(struct policy_locker
*locker
, dm_oblock_t b
)
1780 /* This should never be called */
1785 static int cell_locker(struct policy_locker
*locker
, dm_oblock_t b
)
1787 struct old_oblock_lock
*l
= container_of(locker
, struct old_oblock_lock
, locker
);
1788 struct dm_bio_prison_cell
*cell_prealloc
= prealloc_get_cell(l
->structs
);
1790 return bio_detain(l
->cache
, b
, NULL
, cell_prealloc
,
1791 (cell_free_fn
) prealloc_put_cell
,
1792 l
->structs
, &l
->cell
);
1795 static void process_cell(struct cache
*cache
, struct prealloc
*structs
,
1796 struct dm_bio_prison_cell
*new_ocell
)
1799 bool release_cell
= true;
1800 struct bio
*bio
= new_ocell
->holder
;
1801 dm_oblock_t block
= get_bio_block(cache
, bio
);
1802 struct policy_result lookup_result
;
1803 bool passthrough
= passthrough_mode(&cache
->features
);
1804 bool fast_promotion
, can_migrate
;
1805 struct old_oblock_lock ool
;
1807 fast_promotion
= is_discarded_oblock(cache
, block
) || bio_writes_complete_block(cache
, bio
);
1808 can_migrate
= !passthrough
&& (fast_promotion
|| spare_migration_bandwidth(cache
));
1810 ool
.locker
.fn
= cell_locker
;
1812 ool
.structs
= structs
;
1814 r
= policy_map(cache
->policy
, block
, true, can_migrate
, fast_promotion
,
1815 bio
, &ool
.locker
, &lookup_result
);
1817 if (r
== -EWOULDBLOCK
)
1818 /* migration has been denied */
1819 lookup_result
.op
= POLICY_MISS
;
1821 switch (lookup_result
.op
) {
1824 inc_miss_counter(cache
, bio
);
1827 * Passthrough always maps to the origin,
1828 * invalidating any cache blocks that are written
1832 if (bio_data_dir(bio
) == WRITE
) {
1833 atomic_inc(&cache
->stats
.demotion
);
1834 invalidate(cache
, structs
, block
, lookup_result
.cblock
, new_ocell
);
1835 release_cell
= false;
1838 /* FIXME: factor out issue_origin() */
1839 remap_to_origin_clear_discard(cache
, bio
, block
);
1840 inc_and_issue(cache
, bio
, new_ocell
);
1843 inc_hit_counter(cache
, bio
);
1845 if (bio_data_dir(bio
) == WRITE
&&
1846 writethrough_mode(&cache
->features
) &&
1847 !is_dirty(cache
, lookup_result
.cblock
)) {
1848 remap_to_origin_then_cache(cache
, bio
, block
, lookup_result
.cblock
);
1849 inc_and_issue(cache
, bio
, new_ocell
);
1852 remap_cell_to_cache_dirty(cache
, new_ocell
, block
, lookup_result
.cblock
, true);
1853 release_cell
= false;
1860 inc_miss_counter(cache
, bio
);
1861 remap_cell_to_origin_clear_discard(cache
, new_ocell
, block
, true);
1862 release_cell
= false;
1866 atomic_inc(&cache
->stats
.promotion
);
1867 promote(cache
, structs
, block
, lookup_result
.cblock
, new_ocell
);
1868 release_cell
= false;
1871 case POLICY_REPLACE
:
1872 atomic_inc(&cache
->stats
.demotion
);
1873 atomic_inc(&cache
->stats
.promotion
);
1874 demote_then_promote(cache
, structs
, lookup_result
.old_oblock
,
1875 block
, lookup_result
.cblock
,
1876 ool
.cell
, new_ocell
);
1877 release_cell
= false;
1881 DMERR_LIMIT("%s: %s: erroring bio, unknown policy op: %u",
1882 cache_device_name(cache
), __func__
,
1883 (unsigned) lookup_result
.op
);
1888 cell_defer(cache
, new_ocell
, false);
1891 static void process_bio(struct cache
*cache
, struct prealloc
*structs
,
1895 dm_oblock_t block
= get_bio_block(cache
, bio
);
1896 struct dm_bio_prison_cell
*cell_prealloc
, *new_ocell
;
1899 * Check to see if that block is currently migrating.
1901 cell_prealloc
= prealloc_get_cell(structs
);
1902 r
= bio_detain(cache
, block
, bio
, cell_prealloc
,
1903 (cell_free_fn
) prealloc_put_cell
,
1904 structs
, &new_ocell
);
1908 process_cell(cache
, structs
, new_ocell
);
1911 static int need_commit_due_to_time(struct cache
*cache
)
1913 return jiffies
< cache
->last_commit_jiffies
||
1914 jiffies
> cache
->last_commit_jiffies
+ COMMIT_PERIOD
;
1918 * A non-zero return indicates read_only or fail_io mode.
1920 static int commit(struct cache
*cache
, bool clean_shutdown
)
1924 if (get_cache_mode(cache
) >= CM_READ_ONLY
)
1927 atomic_inc(&cache
->stats
.commit_count
);
1928 r
= dm_cache_commit(cache
->cmd
, clean_shutdown
);
1930 metadata_operation_failed(cache
, "dm_cache_commit", r
);
1935 static int commit_if_needed(struct cache
*cache
)
1939 if ((cache
->commit_requested
|| need_commit_due_to_time(cache
)) &&
1940 dm_cache_changed_this_transaction(cache
->cmd
)) {
1941 r
= commit(cache
, false);
1942 cache
->commit_requested
= false;
1943 cache
->last_commit_jiffies
= jiffies
;
1949 static void process_deferred_bios(struct cache
*cache
)
1951 bool prealloc_used
= false;
1952 unsigned long flags
;
1953 struct bio_list bios
;
1955 struct prealloc structs
;
1957 memset(&structs
, 0, sizeof(structs
));
1958 bio_list_init(&bios
);
1960 spin_lock_irqsave(&cache
->lock
, flags
);
1961 bio_list_merge(&bios
, &cache
->deferred_bios
);
1962 bio_list_init(&cache
->deferred_bios
);
1963 spin_unlock_irqrestore(&cache
->lock
, flags
);
1965 while (!bio_list_empty(&bios
)) {
1967 * If we've got no free migration structs, and processing
1968 * this bio might require one, we pause until there are some
1969 * prepared mappings to process.
1971 prealloc_used
= true;
1972 if (prealloc_data_structs(cache
, &structs
)) {
1973 spin_lock_irqsave(&cache
->lock
, flags
);
1974 bio_list_merge(&cache
->deferred_bios
, &bios
);
1975 spin_unlock_irqrestore(&cache
->lock
, flags
);
1979 bio
= bio_list_pop(&bios
);
1981 if (bio
->bi_rw
& REQ_FLUSH
)
1982 process_flush_bio(cache
, bio
);
1983 else if (bio
->bi_rw
& REQ_DISCARD
)
1984 process_discard_bio(cache
, &structs
, bio
);
1986 process_bio(cache
, &structs
, bio
);
1990 prealloc_free_structs(cache
, &structs
);
1993 static void process_deferred_cells(struct cache
*cache
)
1995 bool prealloc_used
= false;
1996 unsigned long flags
;
1997 struct dm_bio_prison_cell
*cell
, *tmp
;
1998 struct list_head cells
;
1999 struct prealloc structs
;
2001 memset(&structs
, 0, sizeof(structs
));
2003 INIT_LIST_HEAD(&cells
);
2005 spin_lock_irqsave(&cache
->lock
, flags
);
2006 list_splice_init(&cache
->deferred_cells
, &cells
);
2007 spin_unlock_irqrestore(&cache
->lock
, flags
);
2009 list_for_each_entry_safe(cell
, tmp
, &cells
, user_list
) {
2011 * If we've got no free migration structs, and processing
2012 * this bio might require one, we pause until there are some
2013 * prepared mappings to process.
2015 prealloc_used
= true;
2016 if (prealloc_data_structs(cache
, &structs
)) {
2017 spin_lock_irqsave(&cache
->lock
, flags
);
2018 list_splice(&cells
, &cache
->deferred_cells
);
2019 spin_unlock_irqrestore(&cache
->lock
, flags
);
2023 process_cell(cache
, &structs
, cell
);
2027 prealloc_free_structs(cache
, &structs
);
2030 static void process_deferred_flush_bios(struct cache
*cache
, bool submit_bios
)
2032 unsigned long flags
;
2033 struct bio_list bios
;
2036 bio_list_init(&bios
);
2038 spin_lock_irqsave(&cache
->lock
, flags
);
2039 bio_list_merge(&bios
, &cache
->deferred_flush_bios
);
2040 bio_list_init(&cache
->deferred_flush_bios
);
2041 spin_unlock_irqrestore(&cache
->lock
, flags
);
2044 * These bios have already been through inc_ds()
2046 while ((bio
= bio_list_pop(&bios
)))
2047 submit_bios
? accounted_request(cache
, bio
) : bio_io_error(bio
);
2050 static void process_deferred_writethrough_bios(struct cache
*cache
)
2052 unsigned long flags
;
2053 struct bio_list bios
;
2056 bio_list_init(&bios
);
2058 spin_lock_irqsave(&cache
->lock
, flags
);
2059 bio_list_merge(&bios
, &cache
->deferred_writethrough_bios
);
2060 bio_list_init(&cache
->deferred_writethrough_bios
);
2061 spin_unlock_irqrestore(&cache
->lock
, flags
);
2064 * These bios have already been through inc_ds()
2066 while ((bio
= bio_list_pop(&bios
)))
2067 accounted_request(cache
, bio
);
2070 static void writeback_some_dirty_blocks(struct cache
*cache
)
2072 bool prealloc_used
= false;
2075 struct prealloc structs
;
2076 struct dm_bio_prison_cell
*old_ocell
;
2077 bool busy
= !iot_idle_for(&cache
->origin_tracker
, HZ
);
2079 memset(&structs
, 0, sizeof(structs
));
2081 while (spare_migration_bandwidth(cache
)) {
2082 if (policy_writeback_work(cache
->policy
, &oblock
, &cblock
, busy
))
2083 break; /* no work to do */
2085 prealloc_used
= true;
2086 if (prealloc_data_structs(cache
, &structs
) ||
2087 get_cell(cache
, oblock
, &structs
, &old_ocell
)) {
2088 policy_set_dirty(cache
->policy
, oblock
);
2092 writeback(cache
, &structs
, oblock
, cblock
, old_ocell
);
2096 prealloc_free_structs(cache
, &structs
);
2099 /*----------------------------------------------------------------
2101 * Dropping something from the cache *without* writing back.
2102 *--------------------------------------------------------------*/
2104 static void process_invalidation_request(struct cache
*cache
, struct invalidation_request
*req
)
2107 uint64_t begin
= from_cblock(req
->cblocks
->begin
);
2108 uint64_t end
= from_cblock(req
->cblocks
->end
);
2110 while (begin
!= end
) {
2111 r
= policy_remove_cblock(cache
->policy
, to_cblock(begin
));
2113 r
= dm_cache_remove_mapping(cache
->cmd
, to_cblock(begin
));
2115 metadata_operation_failed(cache
, "dm_cache_remove_mapping", r
);
2119 } else if (r
== -ENODATA
) {
2120 /* harmless, already unmapped */
2124 DMERR("%s: policy_remove_cblock failed", cache_device_name(cache
));
2131 cache
->commit_requested
= true;
2134 atomic_set(&req
->complete
, 1);
2136 wake_up(&req
->result_wait
);
2139 static void process_invalidation_requests(struct cache
*cache
)
2141 struct list_head list
;
2142 struct invalidation_request
*req
, *tmp
;
2144 INIT_LIST_HEAD(&list
);
2145 spin_lock(&cache
->invalidation_lock
);
2146 list_splice_init(&cache
->invalidation_requests
, &list
);
2147 spin_unlock(&cache
->invalidation_lock
);
2149 list_for_each_entry_safe (req
, tmp
, &list
, list
)
2150 process_invalidation_request(cache
, req
);
2153 /*----------------------------------------------------------------
2155 *--------------------------------------------------------------*/
2156 static bool is_quiescing(struct cache
*cache
)
2158 return atomic_read(&cache
->quiescing
);
2161 static void ack_quiescing(struct cache
*cache
)
2163 if (is_quiescing(cache
)) {
2164 atomic_inc(&cache
->quiescing_ack
);
2165 wake_up(&cache
->quiescing_wait
);
2169 static void wait_for_quiescing_ack(struct cache
*cache
)
2171 wait_event(cache
->quiescing_wait
, atomic_read(&cache
->quiescing_ack
));
2174 static void start_quiescing(struct cache
*cache
)
2176 atomic_inc(&cache
->quiescing
);
2177 wait_for_quiescing_ack(cache
);
2180 static void stop_quiescing(struct cache
*cache
)
2182 atomic_set(&cache
->quiescing
, 0);
2183 atomic_set(&cache
->quiescing_ack
, 0);
2186 static void wait_for_migrations(struct cache
*cache
)
2188 wait_event(cache
->migration_wait
, !atomic_read(&cache
->nr_allocated_migrations
));
2191 static void stop_worker(struct cache
*cache
)
2193 cancel_delayed_work(&cache
->waker
);
2194 flush_workqueue(cache
->wq
);
2197 static void requeue_deferred_cells(struct cache
*cache
)
2199 unsigned long flags
;
2200 struct list_head cells
;
2201 struct dm_bio_prison_cell
*cell
, *tmp
;
2203 INIT_LIST_HEAD(&cells
);
2204 spin_lock_irqsave(&cache
->lock
, flags
);
2205 list_splice_init(&cache
->deferred_cells
, &cells
);
2206 spin_unlock_irqrestore(&cache
->lock
, flags
);
2208 list_for_each_entry_safe(cell
, tmp
, &cells
, user_list
)
2209 cell_requeue(cache
, cell
);
2212 static void requeue_deferred_bios(struct cache
*cache
)
2215 struct bio_list bios
;
2217 bio_list_init(&bios
);
2218 bio_list_merge(&bios
, &cache
->deferred_bios
);
2219 bio_list_init(&cache
->deferred_bios
);
2221 while ((bio
= bio_list_pop(&bios
))) {
2222 bio
->bi_error
= DM_ENDIO_REQUEUE
;
2227 static int more_work(struct cache
*cache
)
2229 if (is_quiescing(cache
))
2230 return !list_empty(&cache
->quiesced_migrations
) ||
2231 !list_empty(&cache
->completed_migrations
) ||
2232 !list_empty(&cache
->need_commit_migrations
);
2234 return !bio_list_empty(&cache
->deferred_bios
) ||
2235 !list_empty(&cache
->deferred_cells
) ||
2236 !bio_list_empty(&cache
->deferred_flush_bios
) ||
2237 !bio_list_empty(&cache
->deferred_writethrough_bios
) ||
2238 !list_empty(&cache
->quiesced_migrations
) ||
2239 !list_empty(&cache
->completed_migrations
) ||
2240 !list_empty(&cache
->need_commit_migrations
) ||
2244 static void do_worker(struct work_struct
*ws
)
2246 struct cache
*cache
= container_of(ws
, struct cache
, worker
);
2249 if (!is_quiescing(cache
)) {
2250 writeback_some_dirty_blocks(cache
);
2251 process_deferred_writethrough_bios(cache
);
2252 process_deferred_bios(cache
);
2253 process_deferred_cells(cache
);
2254 process_invalidation_requests(cache
);
2257 process_migrations(cache
, &cache
->quiesced_migrations
, issue_copy_or_discard
);
2258 process_migrations(cache
, &cache
->completed_migrations
, complete_migration
);
2260 if (commit_if_needed(cache
)) {
2261 process_deferred_flush_bios(cache
, false);
2262 process_migrations(cache
, &cache
->need_commit_migrations
, migration_failure
);
2264 process_deferred_flush_bios(cache
, true);
2265 process_migrations(cache
, &cache
->need_commit_migrations
,
2266 migration_success_post_commit
);
2269 ack_quiescing(cache
);
2271 } while (more_work(cache
));
2275 * We want to commit periodically so that not too much
2276 * unwritten metadata builds up.
2278 static void do_waker(struct work_struct
*ws
)
2280 struct cache
*cache
= container_of(to_delayed_work(ws
), struct cache
, waker
);
2281 policy_tick(cache
->policy
, true);
2283 queue_delayed_work(cache
->wq
, &cache
->waker
, COMMIT_PERIOD
);
2286 /*----------------------------------------------------------------*/
2288 static int is_congested(struct dm_dev
*dev
, int bdi_bits
)
2290 struct request_queue
*q
= bdev_get_queue(dev
->bdev
);
2291 return bdi_congested(&q
->backing_dev_info
, bdi_bits
);
2294 static int cache_is_congested(struct dm_target_callbacks
*cb
, int bdi_bits
)
2296 struct cache
*cache
= container_of(cb
, struct cache
, callbacks
);
2298 return is_congested(cache
->origin_dev
, bdi_bits
) ||
2299 is_congested(cache
->cache_dev
, bdi_bits
);
2302 /*----------------------------------------------------------------
2304 *--------------------------------------------------------------*/
2307 * This function gets called on the error paths of the constructor, so we
2308 * have to cope with a partially initialised struct.
2310 static void destroy(struct cache
*cache
)
2314 mempool_destroy(cache
->migration_pool
);
2316 if (cache
->all_io_ds
)
2317 dm_deferred_set_destroy(cache
->all_io_ds
);
2320 dm_bio_prison_destroy(cache
->prison
);
2323 destroy_workqueue(cache
->wq
);
2325 if (cache
->dirty_bitset
)
2326 free_bitset(cache
->dirty_bitset
);
2328 if (cache
->discard_bitset
)
2329 free_bitset(cache
->discard_bitset
);
2332 dm_kcopyd_client_destroy(cache
->copier
);
2335 dm_cache_metadata_close(cache
->cmd
);
2337 if (cache
->metadata_dev
)
2338 dm_put_device(cache
->ti
, cache
->metadata_dev
);
2340 if (cache
->origin_dev
)
2341 dm_put_device(cache
->ti
, cache
->origin_dev
);
2343 if (cache
->cache_dev
)
2344 dm_put_device(cache
->ti
, cache
->cache_dev
);
2347 dm_cache_policy_destroy(cache
->policy
);
2349 for (i
= 0; i
< cache
->nr_ctr_args
; i
++)
2350 kfree(cache
->ctr_args
[i
]);
2351 kfree(cache
->ctr_args
);
2356 static void cache_dtr(struct dm_target
*ti
)
2358 struct cache
*cache
= ti
->private;
2363 static sector_t
get_dev_size(struct dm_dev
*dev
)
2365 return i_size_read(dev
->bdev
->bd_inode
) >> SECTOR_SHIFT
;
2368 /*----------------------------------------------------------------*/
2371 * Construct a cache device mapping.
2373 * cache <metadata dev> <cache dev> <origin dev> <block size>
2374 * <#feature args> [<feature arg>]*
2375 * <policy> <#policy args> [<policy arg>]*
2377 * metadata dev : fast device holding the persistent metadata
2378 * cache dev : fast device holding cached data blocks
2379 * origin dev : slow device holding original data blocks
2380 * block size : cache unit size in sectors
2382 * #feature args : number of feature arguments passed
2383 * feature args : writethrough. (The default is writeback.)
2385 * policy : the replacement policy to use
2386 * #policy args : an even number of policy arguments corresponding
2387 * to key/value pairs passed to the policy
2388 * policy args : key/value pairs passed to the policy
2389 * E.g. 'sequential_threshold 1024'
2390 * See cache-policies.txt for details.
2392 * Optional feature arguments are:
2393 * writethrough : write through caching that prohibits cache block
2394 * content from being different from origin block content.
2395 * Without this argument, the default behaviour is to write
2396 * back cache block contents later for performance reasons,
2397 * so they may differ from the corresponding origin blocks.
2400 struct dm_target
*ti
;
2402 struct dm_dev
*metadata_dev
;
2404 struct dm_dev
*cache_dev
;
2405 sector_t cache_sectors
;
2407 struct dm_dev
*origin_dev
;
2408 sector_t origin_sectors
;
2410 uint32_t block_size
;
2412 const char *policy_name
;
2414 const char **policy_argv
;
2416 struct cache_features features
;
2419 static void destroy_cache_args(struct cache_args
*ca
)
2421 if (ca
->metadata_dev
)
2422 dm_put_device(ca
->ti
, ca
->metadata_dev
);
2425 dm_put_device(ca
->ti
, ca
->cache_dev
);
2428 dm_put_device(ca
->ti
, ca
->origin_dev
);
2433 static bool at_least_one_arg(struct dm_arg_set
*as
, char **error
)
2436 *error
= "Insufficient args";
2443 static int parse_metadata_dev(struct cache_args
*ca
, struct dm_arg_set
*as
,
2447 sector_t metadata_dev_size
;
2448 char b
[BDEVNAME_SIZE
];
2450 if (!at_least_one_arg(as
, error
))
2453 r
= dm_get_device(ca
->ti
, dm_shift_arg(as
), FMODE_READ
| FMODE_WRITE
,
2456 *error
= "Error opening metadata device";
2460 metadata_dev_size
= get_dev_size(ca
->metadata_dev
);
2461 if (metadata_dev_size
> DM_CACHE_METADATA_MAX_SECTORS_WARNING
)
2462 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
2463 bdevname(ca
->metadata_dev
->bdev
, b
), THIN_METADATA_MAX_SECTORS
);
2468 static int parse_cache_dev(struct cache_args
*ca
, struct dm_arg_set
*as
,
2473 if (!at_least_one_arg(as
, error
))
2476 r
= dm_get_device(ca
->ti
, dm_shift_arg(as
), FMODE_READ
| FMODE_WRITE
,
2479 *error
= "Error opening cache device";
2482 ca
->cache_sectors
= get_dev_size(ca
->cache_dev
);
2487 static int parse_origin_dev(struct cache_args
*ca
, struct dm_arg_set
*as
,
2492 if (!at_least_one_arg(as
, error
))
2495 r
= dm_get_device(ca
->ti
, dm_shift_arg(as
), FMODE_READ
| FMODE_WRITE
,
2498 *error
= "Error opening origin device";
2502 ca
->origin_sectors
= get_dev_size(ca
->origin_dev
);
2503 if (ca
->ti
->len
> ca
->origin_sectors
) {
2504 *error
= "Device size larger than cached device";
2511 static int parse_block_size(struct cache_args
*ca
, struct dm_arg_set
*as
,
2514 unsigned long block_size
;
2516 if (!at_least_one_arg(as
, error
))
2519 if (kstrtoul(dm_shift_arg(as
), 10, &block_size
) || !block_size
||
2520 block_size
< DATA_DEV_BLOCK_SIZE_MIN_SECTORS
||
2521 block_size
> DATA_DEV_BLOCK_SIZE_MAX_SECTORS
||
2522 block_size
& (DATA_DEV_BLOCK_SIZE_MIN_SECTORS
- 1)) {
2523 *error
= "Invalid data block size";
2527 if (block_size
> ca
->cache_sectors
) {
2528 *error
= "Data block size is larger than the cache device";
2532 ca
->block_size
= block_size
;
2537 static void init_features(struct cache_features
*cf
)
2539 cf
->mode
= CM_WRITE
;
2540 cf
->io_mode
= CM_IO_WRITEBACK
;
2543 static int parse_features(struct cache_args
*ca
, struct dm_arg_set
*as
,
2546 static struct dm_arg _args
[] = {
2547 {0, 1, "Invalid number of cache feature arguments"},
2553 struct cache_features
*cf
= &ca
->features
;
2557 r
= dm_read_arg_group(_args
, as
, &argc
, error
);
2562 arg
= dm_shift_arg(as
);
2564 if (!strcasecmp(arg
, "writeback"))
2565 cf
->io_mode
= CM_IO_WRITEBACK
;
2567 else if (!strcasecmp(arg
, "writethrough"))
2568 cf
->io_mode
= CM_IO_WRITETHROUGH
;
2570 else if (!strcasecmp(arg
, "passthrough"))
2571 cf
->io_mode
= CM_IO_PASSTHROUGH
;
2574 *error
= "Unrecognised cache feature requested";
2582 static int parse_policy(struct cache_args
*ca
, struct dm_arg_set
*as
,
2585 static struct dm_arg _args
[] = {
2586 {0, 1024, "Invalid number of policy arguments"},
2591 if (!at_least_one_arg(as
, error
))
2594 ca
->policy_name
= dm_shift_arg(as
);
2596 r
= dm_read_arg_group(_args
, as
, &ca
->policy_argc
, error
);
2600 ca
->policy_argv
= (const char **)as
->argv
;
2601 dm_consume_args(as
, ca
->policy_argc
);
2606 static int parse_cache_args(struct cache_args
*ca
, int argc
, char **argv
,
2610 struct dm_arg_set as
;
2615 r
= parse_metadata_dev(ca
, &as
, error
);
2619 r
= parse_cache_dev(ca
, &as
, error
);
2623 r
= parse_origin_dev(ca
, &as
, error
);
2627 r
= parse_block_size(ca
, &as
, error
);
2631 r
= parse_features(ca
, &as
, error
);
2635 r
= parse_policy(ca
, &as
, error
);
2642 /*----------------------------------------------------------------*/
2644 static struct kmem_cache
*migration_cache
;
2646 #define NOT_CORE_OPTION 1
2648 static int process_config_option(struct cache
*cache
, const char *key
, const char *value
)
2652 if (!strcasecmp(key
, "migration_threshold")) {
2653 if (kstrtoul(value
, 10, &tmp
))
2656 cache
->migration_threshold
= tmp
;
2660 return NOT_CORE_OPTION
;
2663 static int set_config_value(struct cache
*cache
, const char *key
, const char *value
)
2665 int r
= process_config_option(cache
, key
, value
);
2667 if (r
== NOT_CORE_OPTION
)
2668 r
= policy_set_config_value(cache
->policy
, key
, value
);
2671 DMWARN("bad config value for %s: %s", key
, value
);
2676 static int set_config_values(struct cache
*cache
, int argc
, const char **argv
)
2681 DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs.");
2686 r
= set_config_value(cache
, argv
[0], argv
[1]);
2697 static int create_cache_policy(struct cache
*cache
, struct cache_args
*ca
,
2700 struct dm_cache_policy
*p
= dm_cache_policy_create(ca
->policy_name
,
2702 cache
->origin_sectors
,
2703 cache
->sectors_per_block
);
2705 *error
= "Error creating cache's policy";
2714 * We want the discard block size to be at least the size of the cache
2715 * block size and have no more than 2^14 discard blocks across the origin.
2717 #define MAX_DISCARD_BLOCKS (1 << 14)
2719 static bool too_many_discard_blocks(sector_t discard_block_size
,
2720 sector_t origin_size
)
2722 (void) sector_div(origin_size
, discard_block_size
);
2724 return origin_size
> MAX_DISCARD_BLOCKS
;
2727 static sector_t
calculate_discard_block_size(sector_t cache_block_size
,
2728 sector_t origin_size
)
2730 sector_t discard_block_size
= cache_block_size
;
2733 while (too_many_discard_blocks(discard_block_size
, origin_size
))
2734 discard_block_size
*= 2;
2736 return discard_block_size
;
2739 static void set_cache_size(struct cache
*cache
, dm_cblock_t size
)
2741 dm_block_t nr_blocks
= from_cblock(size
);
2743 if (nr_blocks
> (1 << 20) && cache
->cache_size
!= size
)
2744 DMWARN_LIMIT("You have created a cache device with a lot of individual cache blocks (%llu)\n"
2745 "All these mappings can consume a lot of kernel memory, and take some time to read/write.\n"
2746 "Please consider increasing the cache block size to reduce the overall cache block count.",
2747 (unsigned long long) nr_blocks
);
2749 cache
->cache_size
= size
;
2752 #define DEFAULT_MIGRATION_THRESHOLD 2048
2754 static int cache_create(struct cache_args
*ca
, struct cache
**result
)
2757 char **error
= &ca
->ti
->error
;
2758 struct cache
*cache
;
2759 struct dm_target
*ti
= ca
->ti
;
2760 dm_block_t origin_blocks
;
2761 struct dm_cache_metadata
*cmd
;
2762 bool may_format
= ca
->features
.mode
== CM_WRITE
;
2764 cache
= kzalloc(sizeof(*cache
), GFP_KERNEL
);
2769 ti
->private = cache
;
2770 ti
->num_flush_bios
= 2;
2771 ti
->flush_supported
= true;
2773 ti
->num_discard_bios
= 1;
2774 ti
->discards_supported
= true;
2775 ti
->discard_zeroes_data_unsupported
= true;
2776 ti
->split_discard_bios
= false;
2778 cache
->features
= ca
->features
;
2779 ti
->per_io_data_size
= get_per_bio_data_size(cache
);
2781 cache
->callbacks
.congested_fn
= cache_is_congested
;
2782 dm_table_add_target_callbacks(ti
->table
, &cache
->callbacks
);
2784 cache
->metadata_dev
= ca
->metadata_dev
;
2785 cache
->origin_dev
= ca
->origin_dev
;
2786 cache
->cache_dev
= ca
->cache_dev
;
2788 ca
->metadata_dev
= ca
->origin_dev
= ca
->cache_dev
= NULL
;
2790 /* FIXME: factor out this whole section */
2791 origin_blocks
= cache
->origin_sectors
= ca
->origin_sectors
;
2792 origin_blocks
= block_div(origin_blocks
, ca
->block_size
);
2793 cache
->origin_blocks
= to_oblock(origin_blocks
);
2795 cache
->sectors_per_block
= ca
->block_size
;
2796 if (dm_set_target_max_io_len(ti
, cache
->sectors_per_block
)) {
2801 if (ca
->block_size
& (ca
->block_size
- 1)) {
2802 dm_block_t cache_size
= ca
->cache_sectors
;
2804 cache
->sectors_per_block_shift
= -1;
2805 cache_size
= block_div(cache_size
, ca
->block_size
);
2806 set_cache_size(cache
, to_cblock(cache_size
));
2808 cache
->sectors_per_block_shift
= __ffs(ca
->block_size
);
2809 set_cache_size(cache
, to_cblock(ca
->cache_sectors
>> cache
->sectors_per_block_shift
));
2812 r
= create_cache_policy(cache
, ca
, error
);
2816 cache
->policy_nr_args
= ca
->policy_argc
;
2817 cache
->migration_threshold
= DEFAULT_MIGRATION_THRESHOLD
;
2819 r
= set_config_values(cache
, ca
->policy_argc
, ca
->policy_argv
);
2821 *error
= "Error setting cache policy's config values";
2825 cmd
= dm_cache_metadata_open(cache
->metadata_dev
->bdev
,
2826 ca
->block_size
, may_format
,
2827 dm_cache_policy_get_hint_size(cache
->policy
));
2829 *error
= "Error creating metadata object";
2834 set_cache_mode(cache
, CM_WRITE
);
2835 if (get_cache_mode(cache
) != CM_WRITE
) {
2836 *error
= "Unable to get write access to metadata, please check/repair metadata.";
2841 if (passthrough_mode(&cache
->features
)) {
2844 r
= dm_cache_metadata_all_clean(cache
->cmd
, &all_clean
);
2846 *error
= "dm_cache_metadata_all_clean() failed";
2851 *error
= "Cannot enter passthrough mode unless all blocks are clean";
2857 spin_lock_init(&cache
->lock
);
2858 INIT_LIST_HEAD(&cache
->deferred_cells
);
2859 bio_list_init(&cache
->deferred_bios
);
2860 bio_list_init(&cache
->deferred_flush_bios
);
2861 bio_list_init(&cache
->deferred_writethrough_bios
);
2862 INIT_LIST_HEAD(&cache
->quiesced_migrations
);
2863 INIT_LIST_HEAD(&cache
->completed_migrations
);
2864 INIT_LIST_HEAD(&cache
->need_commit_migrations
);
2865 atomic_set(&cache
->nr_allocated_migrations
, 0);
2866 atomic_set(&cache
->nr_io_migrations
, 0);
2867 init_waitqueue_head(&cache
->migration_wait
);
2869 init_waitqueue_head(&cache
->quiescing_wait
);
2870 atomic_set(&cache
->quiescing
, 0);
2871 atomic_set(&cache
->quiescing_ack
, 0);
2874 atomic_set(&cache
->nr_dirty
, 0);
2875 cache
->dirty_bitset
= alloc_bitset(from_cblock(cache
->cache_size
));
2876 if (!cache
->dirty_bitset
) {
2877 *error
= "could not allocate dirty bitset";
2880 clear_bitset(cache
->dirty_bitset
, from_cblock(cache
->cache_size
));
2882 cache
->discard_block_size
=
2883 calculate_discard_block_size(cache
->sectors_per_block
,
2884 cache
->origin_sectors
);
2885 cache
->discard_nr_blocks
= to_dblock(dm_sector_div_up(cache
->origin_sectors
,
2886 cache
->discard_block_size
));
2887 cache
->discard_bitset
= alloc_bitset(from_dblock(cache
->discard_nr_blocks
));
2888 if (!cache
->discard_bitset
) {
2889 *error
= "could not allocate discard bitset";
2892 clear_bitset(cache
->discard_bitset
, from_dblock(cache
->discard_nr_blocks
));
2894 cache
->copier
= dm_kcopyd_client_create(&dm_kcopyd_throttle
);
2895 if (IS_ERR(cache
->copier
)) {
2896 *error
= "could not create kcopyd client";
2897 r
= PTR_ERR(cache
->copier
);
2901 cache
->wq
= alloc_ordered_workqueue("dm-" DM_MSG_PREFIX
, WQ_MEM_RECLAIM
);
2903 *error
= "could not create workqueue for metadata object";
2906 INIT_WORK(&cache
->worker
, do_worker
);
2907 INIT_DELAYED_WORK(&cache
->waker
, do_waker
);
2908 cache
->last_commit_jiffies
= jiffies
;
2910 cache
->prison
= dm_bio_prison_create();
2911 if (!cache
->prison
) {
2912 *error
= "could not create bio prison";
2916 cache
->all_io_ds
= dm_deferred_set_create();
2917 if (!cache
->all_io_ds
) {
2918 *error
= "could not create all_io deferred set";
2922 cache
->migration_pool
= mempool_create_slab_pool(MIGRATION_POOL_SIZE
,
2924 if (!cache
->migration_pool
) {
2925 *error
= "Error creating cache's migration mempool";
2929 cache
->need_tick_bio
= true;
2930 cache
->sized
= false;
2931 cache
->invalidate
= false;
2932 cache
->commit_requested
= false;
2933 cache
->loaded_mappings
= false;
2934 cache
->loaded_discards
= false;
2938 atomic_set(&cache
->stats
.demotion
, 0);
2939 atomic_set(&cache
->stats
.promotion
, 0);
2940 atomic_set(&cache
->stats
.copies_avoided
, 0);
2941 atomic_set(&cache
->stats
.cache_cell_clash
, 0);
2942 atomic_set(&cache
->stats
.commit_count
, 0);
2943 atomic_set(&cache
->stats
.discard_count
, 0);
2945 spin_lock_init(&cache
->invalidation_lock
);
2946 INIT_LIST_HEAD(&cache
->invalidation_requests
);
2948 iot_init(&cache
->origin_tracker
);
2958 static int copy_ctr_args(struct cache
*cache
, int argc
, const char **argv
)
2963 copy
= kcalloc(argc
, sizeof(*copy
), GFP_KERNEL
);
2966 for (i
= 0; i
< argc
; i
++) {
2967 copy
[i
] = kstrdup(argv
[i
], GFP_KERNEL
);
2976 cache
->nr_ctr_args
= argc
;
2977 cache
->ctr_args
= copy
;
2982 static int cache_ctr(struct dm_target
*ti
, unsigned argc
, char **argv
)
2985 struct cache_args
*ca
;
2986 struct cache
*cache
= NULL
;
2988 ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
2990 ti
->error
= "Error allocating memory for cache";
2995 r
= parse_cache_args(ca
, argc
, argv
, &ti
->error
);
2999 r
= cache_create(ca
, &cache
);
3003 r
= copy_ctr_args(cache
, argc
- 3, (const char **)argv
+ 3);
3009 ti
->private = cache
;
3012 destroy_cache_args(ca
);
3016 /*----------------------------------------------------------------*/
3018 static int cache_map(struct dm_target
*ti
, struct bio
*bio
)
3020 struct cache
*cache
= ti
->private;
3023 struct dm_bio_prison_cell
*cell
= NULL
;
3024 dm_oblock_t block
= get_bio_block(cache
, bio
);
3025 size_t pb_data_size
= get_per_bio_data_size(cache
);
3026 bool can_migrate
= false;
3027 bool fast_promotion
;
3028 struct policy_result lookup_result
;
3029 struct per_bio_data
*pb
= init_per_bio_data(bio
, pb_data_size
);
3030 struct old_oblock_lock ool
;
3032 ool
.locker
.fn
= null_locker
;
3034 if (unlikely(from_oblock(block
) >= from_oblock(cache
->origin_blocks
))) {
3036 * This can only occur if the io goes to a partial block at
3037 * the end of the origin device. We don't cache these.
3038 * Just remap to the origin and carry on.
3040 remap_to_origin(cache
, bio
);
3041 accounted_begin(cache
, bio
);
3042 return DM_MAPIO_REMAPPED
;
3045 if (discard_or_flush(bio
)) {
3046 defer_bio(cache
, bio
);
3047 return DM_MAPIO_SUBMITTED
;
3051 * Check to see if that block is currently migrating.
3053 cell
= alloc_prison_cell(cache
);
3055 defer_bio(cache
, bio
);
3056 return DM_MAPIO_SUBMITTED
;
3059 r
= bio_detain(cache
, block
, bio
, cell
,
3060 (cell_free_fn
) free_prison_cell
,
3064 defer_bio(cache
, bio
);
3066 return DM_MAPIO_SUBMITTED
;
3069 fast_promotion
= is_discarded_oblock(cache
, block
) || bio_writes_complete_block(cache
, bio
);
3071 r
= policy_map(cache
->policy
, block
, false, can_migrate
, fast_promotion
,
3072 bio
, &ool
.locker
, &lookup_result
);
3073 if (r
== -EWOULDBLOCK
) {
3074 cell_defer(cache
, cell
, true);
3075 return DM_MAPIO_SUBMITTED
;
3078 DMERR_LIMIT("%s: Unexpected return from cache replacement policy: %d",
3079 cache_device_name(cache
), r
);
3080 cell_defer(cache
, cell
, false);
3082 return DM_MAPIO_SUBMITTED
;
3085 r
= DM_MAPIO_REMAPPED
;
3086 switch (lookup_result
.op
) {
3088 if (passthrough_mode(&cache
->features
)) {
3089 if (bio_data_dir(bio
) == WRITE
) {
3091 * We need to invalidate this block, so
3092 * defer for the worker thread.
3094 cell_defer(cache
, cell
, true);
3095 r
= DM_MAPIO_SUBMITTED
;
3098 inc_miss_counter(cache
, bio
);
3099 remap_to_origin_clear_discard(cache
, bio
, block
);
3100 accounted_begin(cache
, bio
);
3101 inc_ds(cache
, bio
, cell
);
3102 // FIXME: we want to remap hits or misses straight
3103 // away rather than passing over to the worker.
3104 cell_defer(cache
, cell
, false);
3108 inc_hit_counter(cache
, bio
);
3109 if (bio_data_dir(bio
) == WRITE
&& writethrough_mode(&cache
->features
) &&
3110 !is_dirty(cache
, lookup_result
.cblock
)) {
3111 remap_to_origin_then_cache(cache
, bio
, block
, lookup_result
.cblock
);
3112 accounted_begin(cache
, bio
);
3113 inc_ds(cache
, bio
, cell
);
3114 cell_defer(cache
, cell
, false);
3117 remap_cell_to_cache_dirty(cache
, cell
, block
, lookup_result
.cblock
, false);
3122 inc_miss_counter(cache
, bio
);
3123 if (pb
->req_nr
!= 0) {
3125 * This is a duplicate writethrough io that is no
3126 * longer needed because the block has been demoted.
3129 // FIXME: remap everything as a miss
3130 cell_defer(cache
, cell
, false);
3131 r
= DM_MAPIO_SUBMITTED
;
3134 remap_cell_to_origin_clear_discard(cache
, cell
, block
, false);
3138 DMERR_LIMIT("%s: %s: erroring bio: unknown policy op: %u",
3139 cache_device_name(cache
), __func__
,
3140 (unsigned) lookup_result
.op
);
3141 cell_defer(cache
, cell
, false);
3143 r
= DM_MAPIO_SUBMITTED
;
3149 static int cache_end_io(struct dm_target
*ti
, struct bio
*bio
, int error
)
3151 struct cache
*cache
= ti
->private;
3152 unsigned long flags
;
3153 size_t pb_data_size
= get_per_bio_data_size(cache
);
3154 struct per_bio_data
*pb
= get_per_bio_data(bio
, pb_data_size
);
3157 policy_tick(cache
->policy
, false);
3159 spin_lock_irqsave(&cache
->lock
, flags
);
3160 cache
->need_tick_bio
= true;
3161 spin_unlock_irqrestore(&cache
->lock
, flags
);
3164 check_for_quiesced_migrations(cache
, pb
);
3165 accounted_complete(cache
, bio
);
3170 static int write_dirty_bitset(struct cache
*cache
)
3174 if (get_cache_mode(cache
) >= CM_READ_ONLY
)
3177 for (i
= 0; i
< from_cblock(cache
->cache_size
); i
++) {
3178 r
= dm_cache_set_dirty(cache
->cmd
, to_cblock(i
),
3179 is_dirty(cache
, to_cblock(i
)));
3181 metadata_operation_failed(cache
, "dm_cache_set_dirty", r
);
3189 static int write_discard_bitset(struct cache
*cache
)
3193 if (get_cache_mode(cache
) >= CM_READ_ONLY
)
3196 r
= dm_cache_discard_bitset_resize(cache
->cmd
, cache
->discard_block_size
,
3197 cache
->discard_nr_blocks
);
3199 DMERR("%s: could not resize on-disk discard bitset", cache_device_name(cache
));
3200 metadata_operation_failed(cache
, "dm_cache_discard_bitset_resize", r
);
3204 for (i
= 0; i
< from_dblock(cache
->discard_nr_blocks
); i
++) {
3205 r
= dm_cache_set_discard(cache
->cmd
, to_dblock(i
),
3206 is_discarded(cache
, to_dblock(i
)));
3208 metadata_operation_failed(cache
, "dm_cache_set_discard", r
);
3216 static int write_hints(struct cache
*cache
)
3220 if (get_cache_mode(cache
) >= CM_READ_ONLY
)
3223 r
= dm_cache_write_hints(cache
->cmd
, cache
->policy
);
3225 metadata_operation_failed(cache
, "dm_cache_write_hints", r
);
3233 * returns true on success
3235 static bool sync_metadata(struct cache
*cache
)
3239 r1
= write_dirty_bitset(cache
);
3241 DMERR("%s: could not write dirty bitset", cache_device_name(cache
));
3243 r2
= write_discard_bitset(cache
);
3245 DMERR("%s: could not write discard bitset", cache_device_name(cache
));
3249 r3
= write_hints(cache
);
3251 DMERR("%s: could not write hints", cache_device_name(cache
));
3254 * If writing the above metadata failed, we still commit, but don't
3255 * set the clean shutdown flag. This will effectively force every
3256 * dirty bit to be set on reload.
3258 r4
= commit(cache
, !r1
&& !r2
&& !r3
);
3260 DMERR("%s: could not write cache metadata", cache_device_name(cache
));
3262 return !r1
&& !r2
&& !r3
&& !r4
;
3265 static void cache_postsuspend(struct dm_target
*ti
)
3267 struct cache
*cache
= ti
->private;
3269 start_quiescing(cache
);
3270 wait_for_migrations(cache
);
3272 requeue_deferred_bios(cache
);
3273 requeue_deferred_cells(cache
);
3274 stop_quiescing(cache
);
3276 if (get_cache_mode(cache
) == CM_WRITE
)
3277 (void) sync_metadata(cache
);
3280 static int load_mapping(void *context
, dm_oblock_t oblock
, dm_cblock_t cblock
,
3281 bool dirty
, uint32_t hint
, bool hint_valid
)
3284 struct cache
*cache
= context
;
3286 r
= policy_load_mapping(cache
->policy
, oblock
, cblock
, hint
, hint_valid
);
3291 set_dirty(cache
, oblock
, cblock
);
3293 clear_dirty(cache
, oblock
, cblock
);
3299 * The discard block size in the on disk metadata is not
3300 * neccessarily the same as we're currently using. So we have to
3301 * be careful to only set the discarded attribute if we know it
3302 * covers a complete block of the new size.
3304 struct discard_load_info
{
3305 struct cache
*cache
;
3308 * These blocks are sized using the on disk dblock size, rather
3309 * than the current one.
3311 dm_block_t block_size
;
3312 dm_block_t discard_begin
, discard_end
;
3315 static void discard_load_info_init(struct cache
*cache
,
3316 struct discard_load_info
*li
)
3319 li
->discard_begin
= li
->discard_end
= 0;
3322 static void set_discard_range(struct discard_load_info
*li
)
3326 if (li
->discard_begin
== li
->discard_end
)
3330 * Convert to sectors.
3332 b
= li
->discard_begin
* li
->block_size
;
3333 e
= li
->discard_end
* li
->block_size
;
3336 * Then convert back to the current dblock size.
3338 b
= dm_sector_div_up(b
, li
->cache
->discard_block_size
);
3339 sector_div(e
, li
->cache
->discard_block_size
);
3342 * The origin may have shrunk, so we need to check we're still in
3345 if (e
> from_dblock(li
->cache
->discard_nr_blocks
))
3346 e
= from_dblock(li
->cache
->discard_nr_blocks
);
3349 set_discard(li
->cache
, to_dblock(b
));
3352 static int load_discard(void *context
, sector_t discard_block_size
,
3353 dm_dblock_t dblock
, bool discard
)
3355 struct discard_load_info
*li
= context
;
3357 li
->block_size
= discard_block_size
;
3360 if (from_dblock(dblock
) == li
->discard_end
)
3362 * We're already in a discard range, just extend it.
3364 li
->discard_end
= li
->discard_end
+ 1ULL;
3368 * Emit the old range and start a new one.
3370 set_discard_range(li
);
3371 li
->discard_begin
= from_dblock(dblock
);
3372 li
->discard_end
= li
->discard_begin
+ 1ULL;
3375 set_discard_range(li
);
3376 li
->discard_begin
= li
->discard_end
= 0;
3382 static dm_cblock_t
get_cache_dev_size(struct cache
*cache
)
3384 sector_t size
= get_dev_size(cache
->cache_dev
);
3385 (void) sector_div(size
, cache
->sectors_per_block
);
3386 return to_cblock(size
);
3389 static bool can_resize(struct cache
*cache
, dm_cblock_t new_size
)
3391 if (from_cblock(new_size
) > from_cblock(cache
->cache_size
))
3395 * We can't drop a dirty block when shrinking the cache.
3397 while (from_cblock(new_size
) < from_cblock(cache
->cache_size
)) {
3398 new_size
= to_cblock(from_cblock(new_size
) + 1);
3399 if (is_dirty(cache
, new_size
)) {
3400 DMERR("%s: unable to shrink cache; cache block %llu is dirty",
3401 cache_device_name(cache
),
3402 (unsigned long long) from_cblock(new_size
));
3410 static int resize_cache_dev(struct cache
*cache
, dm_cblock_t new_size
)
3414 r
= dm_cache_resize(cache
->cmd
, new_size
);
3416 DMERR("%s: could not resize cache metadata", cache_device_name(cache
));
3417 metadata_operation_failed(cache
, "dm_cache_resize", r
);
3421 set_cache_size(cache
, new_size
);
3426 static int cache_preresume(struct dm_target
*ti
)
3429 struct cache
*cache
= ti
->private;
3430 dm_cblock_t csize
= get_cache_dev_size(cache
);
3433 * Check to see if the cache has resized.
3435 if (!cache
->sized
) {
3436 r
= resize_cache_dev(cache
, csize
);
3440 cache
->sized
= true;
3442 } else if (csize
!= cache
->cache_size
) {
3443 if (!can_resize(cache
, csize
))
3446 r
= resize_cache_dev(cache
, csize
);
3451 if (!cache
->loaded_mappings
) {
3452 r
= dm_cache_load_mappings(cache
->cmd
, cache
->policy
,
3453 load_mapping
, cache
);
3455 DMERR("%s: could not load cache mappings", cache_device_name(cache
));
3456 metadata_operation_failed(cache
, "dm_cache_load_mappings", r
);
3460 cache
->loaded_mappings
= true;
3463 if (!cache
->loaded_discards
) {
3464 struct discard_load_info li
;
3467 * The discard bitset could have been resized, or the
3468 * discard block size changed. To be safe we start by
3469 * setting every dblock to not discarded.
3471 clear_bitset(cache
->discard_bitset
, from_dblock(cache
->discard_nr_blocks
));
3473 discard_load_info_init(cache
, &li
);
3474 r
= dm_cache_load_discards(cache
->cmd
, load_discard
, &li
);
3476 DMERR("%s: could not load origin discards", cache_device_name(cache
));
3477 metadata_operation_failed(cache
, "dm_cache_load_discards", r
);
3480 set_discard_range(&li
);
3482 cache
->loaded_discards
= true;
3488 static void cache_resume(struct dm_target
*ti
)
3490 struct cache
*cache
= ti
->private;
3492 cache
->need_tick_bio
= true;
3493 do_waker(&cache
->waker
.work
);
3499 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
3500 * <cache block size> <#used cache blocks>/<#total cache blocks>
3501 * <#read hits> <#read misses> <#write hits> <#write misses>
3502 * <#demotions> <#promotions> <#dirty>
3503 * <#features> <features>*
3504 * <#core args> <core args>
3505 * <policy name> <#policy args> <policy args>* <cache metadata mode> <needs_check>
3507 static void cache_status(struct dm_target
*ti
, status_type_t type
,
3508 unsigned status_flags
, char *result
, unsigned maxlen
)
3513 dm_block_t nr_free_blocks_metadata
= 0;
3514 dm_block_t nr_blocks_metadata
= 0;
3515 char buf
[BDEVNAME_SIZE
];
3516 struct cache
*cache
= ti
->private;
3517 dm_cblock_t residency
;
3521 case STATUSTYPE_INFO
:
3522 if (get_cache_mode(cache
) == CM_FAIL
) {
3527 /* Commit to ensure statistics aren't out-of-date */
3528 if (!(status_flags
& DM_STATUS_NOFLUSH_FLAG
) && !dm_suspended(ti
))
3529 (void) commit(cache
, false);
3531 r
= dm_cache_get_free_metadata_block_count(cache
->cmd
, &nr_free_blocks_metadata
);
3533 DMERR("%s: dm_cache_get_free_metadata_block_count returned %d",
3534 cache_device_name(cache
), r
);
3538 r
= dm_cache_get_metadata_dev_size(cache
->cmd
, &nr_blocks_metadata
);
3540 DMERR("%s: dm_cache_get_metadata_dev_size returned %d",
3541 cache_device_name(cache
), r
);
3545 residency
= policy_residency(cache
->policy
);
3547 DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %lu ",
3548 (unsigned)DM_CACHE_METADATA_BLOCK_SIZE
,
3549 (unsigned long long)(nr_blocks_metadata
- nr_free_blocks_metadata
),
3550 (unsigned long long)nr_blocks_metadata
,
3551 cache
->sectors_per_block
,
3552 (unsigned long long) from_cblock(residency
),
3553 (unsigned long long) from_cblock(cache
->cache_size
),
3554 (unsigned) atomic_read(&cache
->stats
.read_hit
),
3555 (unsigned) atomic_read(&cache
->stats
.read_miss
),
3556 (unsigned) atomic_read(&cache
->stats
.write_hit
),
3557 (unsigned) atomic_read(&cache
->stats
.write_miss
),
3558 (unsigned) atomic_read(&cache
->stats
.demotion
),
3559 (unsigned) atomic_read(&cache
->stats
.promotion
),
3560 (unsigned long) atomic_read(&cache
->nr_dirty
));
3562 if (writethrough_mode(&cache
->features
))
3563 DMEMIT("1 writethrough ");
3565 else if (passthrough_mode(&cache
->features
))
3566 DMEMIT("1 passthrough ");
3568 else if (writeback_mode(&cache
->features
))
3569 DMEMIT("1 writeback ");
3572 DMERR("%s: internal error: unknown io mode: %d",
3573 cache_device_name(cache
), (int) cache
->features
.io_mode
);
3577 DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache
->migration_threshold
);
3579 DMEMIT("%s ", dm_cache_policy_get_name(cache
->policy
));
3581 r
= policy_emit_config_values(cache
->policy
, result
, maxlen
, &sz
);
3583 DMERR("%s: policy_emit_config_values returned %d",
3584 cache_device_name(cache
), r
);
3587 if (get_cache_mode(cache
) == CM_READ_ONLY
)
3592 r
= dm_cache_metadata_needs_check(cache
->cmd
, &needs_check
);
3594 if (r
|| needs_check
)
3595 DMEMIT("needs_check ");
3601 case STATUSTYPE_TABLE
:
3602 format_dev_t(buf
, cache
->metadata_dev
->bdev
->bd_dev
);
3604 format_dev_t(buf
, cache
->cache_dev
->bdev
->bd_dev
);
3606 format_dev_t(buf
, cache
->origin_dev
->bdev
->bd_dev
);
3609 for (i
= 0; i
< cache
->nr_ctr_args
- 1; i
++)
3610 DMEMIT(" %s", cache
->ctr_args
[i
]);
3611 if (cache
->nr_ctr_args
)
3612 DMEMIT(" %s", cache
->ctr_args
[cache
->nr_ctr_args
- 1]);
3622 * A cache block range can take two forms:
3624 * i) A single cblock, eg. '3456'
3625 * ii) A begin and end cblock with dots between, eg. 123-234
3627 static int parse_cblock_range(struct cache
*cache
, const char *str
,
3628 struct cblock_range
*result
)
3635 * Try and parse form (ii) first.
3637 r
= sscanf(str
, "%llu-%llu%c", &b
, &e
, &dummy
);
3642 result
->begin
= to_cblock(b
);
3643 result
->end
= to_cblock(e
);
3648 * That didn't work, try form (i).
3650 r
= sscanf(str
, "%llu%c", &b
, &dummy
);
3655 result
->begin
= to_cblock(b
);
3656 result
->end
= to_cblock(from_cblock(result
->begin
) + 1u);
3660 DMERR("%s: invalid cblock range '%s'", cache_device_name(cache
), str
);
3664 static int validate_cblock_range(struct cache
*cache
, struct cblock_range
*range
)
3666 uint64_t b
= from_cblock(range
->begin
);
3667 uint64_t e
= from_cblock(range
->end
);
3668 uint64_t n
= from_cblock(cache
->cache_size
);
3671 DMERR("%s: begin cblock out of range: %llu >= %llu",
3672 cache_device_name(cache
), b
, n
);
3677 DMERR("%s: end cblock out of range: %llu > %llu",
3678 cache_device_name(cache
), e
, n
);
3683 DMERR("%s: invalid cblock range: %llu >= %llu",
3684 cache_device_name(cache
), b
, e
);
3691 static int request_invalidation(struct cache
*cache
, struct cblock_range
*range
)
3693 struct invalidation_request req
;
3695 INIT_LIST_HEAD(&req
.list
);
3696 req
.cblocks
= range
;
3697 atomic_set(&req
.complete
, 0);
3699 init_waitqueue_head(&req
.result_wait
);
3701 spin_lock(&cache
->invalidation_lock
);
3702 list_add(&req
.list
, &cache
->invalidation_requests
);
3703 spin_unlock(&cache
->invalidation_lock
);
3706 wait_event(req
.result_wait
, atomic_read(&req
.complete
));
3710 static int process_invalidate_cblocks_message(struct cache
*cache
, unsigned count
,
3711 const char **cblock_ranges
)
3715 struct cblock_range range
;
3717 if (!passthrough_mode(&cache
->features
)) {
3718 DMERR("%s: cache has to be in passthrough mode for invalidation",
3719 cache_device_name(cache
));
3723 for (i
= 0; i
< count
; i
++) {
3724 r
= parse_cblock_range(cache
, cblock_ranges
[i
], &range
);
3728 r
= validate_cblock_range(cache
, &range
);
3733 * Pass begin and end origin blocks to the worker and wake it.
3735 r
= request_invalidation(cache
, &range
);
3747 * "invalidate_cblocks [(<begin>)|(<begin>-<end>)]*
3749 * The key migration_threshold is supported by the cache target core.
3751 static int cache_message(struct dm_target
*ti
, unsigned argc
, char **argv
)
3753 struct cache
*cache
= ti
->private;
3758 if (get_cache_mode(cache
) >= CM_READ_ONLY
) {
3759 DMERR("%s: unable to service cache target messages in READ_ONLY or FAIL mode",
3760 cache_device_name(cache
));
3764 if (!strcasecmp(argv
[0], "invalidate_cblocks"))
3765 return process_invalidate_cblocks_message(cache
, argc
- 1, (const char **) argv
+ 1);
3770 return set_config_value(cache
, argv
[0], argv
[1]);
3773 static int cache_iterate_devices(struct dm_target
*ti
,
3774 iterate_devices_callout_fn fn
, void *data
)
3777 struct cache
*cache
= ti
->private;
3779 r
= fn(ti
, cache
->cache_dev
, 0, get_dev_size(cache
->cache_dev
), data
);
3781 r
= fn(ti
, cache
->origin_dev
, 0, ti
->len
, data
);
3786 static void set_discard_limits(struct cache
*cache
, struct queue_limits
*limits
)
3789 * FIXME: these limits may be incompatible with the cache device
3791 limits
->max_discard_sectors
= min_t(sector_t
, cache
->discard_block_size
* 1024,
3792 cache
->origin_sectors
);
3793 limits
->discard_granularity
= cache
->discard_block_size
<< SECTOR_SHIFT
;
3796 static void cache_io_hints(struct dm_target
*ti
, struct queue_limits
*limits
)
3798 struct cache
*cache
= ti
->private;
3799 uint64_t io_opt_sectors
= limits
->io_opt
>> SECTOR_SHIFT
;
3802 * If the system-determined stacked limits are compatible with the
3803 * cache's blocksize (io_opt is a factor) do not override them.
3805 if (io_opt_sectors
< cache
->sectors_per_block
||
3806 do_div(io_opt_sectors
, cache
->sectors_per_block
)) {
3807 blk_limits_io_min(limits
, cache
->sectors_per_block
<< SECTOR_SHIFT
);
3808 blk_limits_io_opt(limits
, cache
->sectors_per_block
<< SECTOR_SHIFT
);
3810 set_discard_limits(cache
, limits
);
3813 /*----------------------------------------------------------------*/
3815 static struct target_type cache_target
= {
3817 .version
= {1, 9, 0},
3818 .module
= THIS_MODULE
,
3822 .end_io
= cache_end_io
,
3823 .postsuspend
= cache_postsuspend
,
3824 .preresume
= cache_preresume
,
3825 .resume
= cache_resume
,
3826 .status
= cache_status
,
3827 .message
= cache_message
,
3828 .iterate_devices
= cache_iterate_devices
,
3829 .io_hints
= cache_io_hints
,
3832 static int __init
dm_cache_init(void)
3836 r
= dm_register_target(&cache_target
);
3838 DMERR("cache target registration failed: %d", r
);
3842 migration_cache
= KMEM_CACHE(dm_cache_migration
, 0);
3843 if (!migration_cache
) {
3844 dm_unregister_target(&cache_target
);
3851 static void __exit
dm_cache_exit(void)
3853 dm_unregister_target(&cache_target
);
3854 kmem_cache_destroy(migration_cache
);
3857 module_init(dm_cache_init
);
3858 module_exit(dm_cache_exit
);
3860 MODULE_DESCRIPTION(DM_NAME
" cache target");
3861 MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
3862 MODULE_LICENSE("GPL");