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;
124 static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio,
125 bio_end_io_t *bi_end_io, void *bi_private)
127 h->bi_end_io = bio->bi_end_io;
128 h->bi_private = bio->bi_private;
130 bio->bi_end_io = bi_end_io;
131 bio->bi_private = bi_private;
134 static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio)
136 bio->bi_end_io = h->bi_end_io;
137 bio->bi_private = h->bi_private;
140 /*----------------------------------------------------------------*/
142 #define MIGRATION_POOL_SIZE 128
143 #define COMMIT_PERIOD HZ
144 #define MIGRATION_COUNT_WINDOW 10
147 * The block size of the device holding cache data must be
148 * between 32KB and 1GB.
150 #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT)
151 #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
153 enum cache_metadata_mode {
154 CM_WRITE, /* metadata may be changed */
155 CM_READ_ONLY, /* metadata may not be changed */
161 * Data is written to cached blocks only. These blocks are marked
162 * dirty. If you lose the cache device you will lose data.
163 * Potential performance increase for both reads and writes.
168 * Data is written to both cache and origin. Blocks are never
169 * dirty. Potential performance benfit for reads only.
174 * A degraded mode useful for various cache coherency situations
175 * (eg, rolling back snapshots). Reads and writes always go to the
176 * origin. If a write goes to a cached oblock, then the cache
177 * block is invalidated.
182 struct cache_features {
183 enum cache_metadata_mode mode;
184 enum cache_io_mode io_mode;
194 atomic_t copies_avoided;
195 atomic_t cache_cell_clash;
196 atomic_t commit_count;
197 atomic_t discard_count;
201 * Defines a range of cblocks, begin to (end - 1) are in the range. end is
202 * the one-past-the-end value.
204 struct cblock_range {
209 struct invalidation_request {
210 struct list_head list;
211 struct cblock_range *cblocks;
216 wait_queue_head_t result_wait;
220 struct dm_target *ti;
221 struct dm_target_callbacks callbacks;
223 struct dm_cache_metadata *cmd;
226 * Metadata is written to this device.
228 struct dm_dev *metadata_dev;
231 * The slower of the two data devices. Typically a spindle.
233 struct dm_dev *origin_dev;
236 * The faster of the two data devices. Typically an SSD.
238 struct dm_dev *cache_dev;
241 * Size of the origin device in _complete_ blocks and native sectors.
243 dm_oblock_t origin_blocks;
244 sector_t origin_sectors;
247 * Size of the cache device in blocks.
249 dm_cblock_t cache_size;
252 * Fields for converting from sectors to blocks.
254 uint32_t sectors_per_block;
255 int sectors_per_block_shift;
258 struct list_head deferred_cells;
259 struct bio_list deferred_bios;
260 struct bio_list deferred_flush_bios;
261 struct bio_list deferred_writethrough_bios;
262 struct list_head quiesced_migrations;
263 struct list_head completed_migrations;
264 struct list_head need_commit_migrations;
265 sector_t migration_threshold;
266 wait_queue_head_t migration_wait;
267 atomic_t nr_allocated_migrations;
270 * The number of in flight migrations that are performing
271 * background io. eg, promotion, writeback.
273 atomic_t nr_io_migrations;
275 wait_queue_head_t quiescing_wait;
277 atomic_t quiescing_ack;
280 * cache_size entries, dirty if set
283 unsigned long *dirty_bitset;
286 * origin_blocks entries, discarded if set.
288 dm_dblock_t discard_nr_blocks;
289 unsigned long *discard_bitset;
290 uint32_t discard_block_size; /* a power of 2 times sectors per block */
293 * Rather than reconstructing the table line for the status we just
294 * save it and regurgitate.
296 unsigned nr_ctr_args;
297 const char **ctr_args;
299 struct dm_kcopyd_client *copier;
300 struct workqueue_struct *wq;
301 struct work_struct worker;
303 struct delayed_work waker;
304 unsigned long last_commit_jiffies;
306 struct dm_bio_prison *prison;
307 struct dm_deferred_set *all_io_ds;
309 mempool_t *migration_pool;
311 struct dm_cache_policy *policy;
312 unsigned policy_nr_args;
314 bool need_tick_bio:1;
317 bool commit_requested:1;
318 bool loaded_mappings:1;
319 bool loaded_discards:1;
322 * Cache features such as write-through.
324 struct cache_features features;
326 struct cache_stats stats;
329 * Invalidation fields.
331 spinlock_t invalidation_lock;
332 struct list_head invalidation_requests;
334 struct io_tracker origin_tracker;
337 struct per_bio_data {
340 struct dm_deferred_entry *all_io_entry;
341 struct dm_hook_info hook_info;
345 * writethrough fields. These MUST remain at the end of this
346 * structure and the 'cache' member must be the first as it
347 * is used to determine the offset of the writethrough fields.
351 struct dm_bio_details bio_details;
354 struct dm_cache_migration {
355 struct list_head list;
358 unsigned long start_jiffies;
359 dm_oblock_t old_oblock;
360 dm_oblock_t new_oblock;
368 bool requeue_holder:1;
371 struct dm_bio_prison_cell *old_ocell;
372 struct dm_bio_prison_cell *new_ocell;
376 * Processing a bio in the worker thread may require these memory
377 * allocations. We prealloc to avoid deadlocks (the same worker thread
378 * frees them back to the mempool).
381 struct dm_cache_migration *mg;
382 struct dm_bio_prison_cell *cell1;
383 struct dm_bio_prison_cell *cell2;
386 static enum cache_metadata_mode get_cache_mode(struct cache *cache);
388 static void wake_worker(struct cache *cache)
390 queue_work(cache->wq, &cache->worker);
393 /*----------------------------------------------------------------*/
395 static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache)
397 /* FIXME: change to use a local slab. */
398 return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT);
401 static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell)
403 dm_bio_prison_free_cell(cache->prison, cell);
406 static struct dm_cache_migration *alloc_migration(struct cache *cache)
408 struct dm_cache_migration *mg;
410 mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);
413 atomic_inc(&mg->cache->nr_allocated_migrations);
419 static void free_migration(struct dm_cache_migration *mg)
421 struct cache *cache = mg->cache;
423 if (atomic_dec_and_test(&cache->nr_allocated_migrations))
424 wake_up(&cache->migration_wait);
426 mempool_free(mg, cache->migration_pool);
429 static int prealloc_data_structs(struct cache *cache, struct prealloc *p)
432 p->mg = alloc_migration(cache);
438 p->cell1 = alloc_prison_cell(cache);
444 p->cell2 = alloc_prison_cell(cache);
452 static void prealloc_free_structs(struct cache *cache, struct prealloc *p)
455 free_prison_cell(cache, p->cell2);
458 free_prison_cell(cache, p->cell1);
461 free_migration(p->mg);
464 static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p)
466 struct dm_cache_migration *mg = p->mg;
475 * You must have a cell within the prealloc struct to return. If not this
476 * function will BUG() rather than returning NULL.
478 static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p)
480 struct dm_bio_prison_cell *r = NULL;
486 } else if (p->cell2) {
496 * You can't have more than two cells in a prealloc struct. BUG() will be
497 * called if you try and overfill.
499 static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell)
511 /*----------------------------------------------------------------*/
513 static void build_key(dm_oblock_t begin, dm_oblock_t end, struct dm_cell_key *key)
517 key->block_begin = from_oblock(begin);
518 key->block_end = from_oblock(end);
522 * The caller hands in a preallocated cell, and a free function for it.
523 * The cell will be freed if there's an error, or if it wasn't used because
524 * a cell with that key already exists.
526 typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell);
528 static int bio_detain_range(struct cache *cache, dm_oblock_t oblock_begin, dm_oblock_t oblock_end,
529 struct bio *bio, struct dm_bio_prison_cell *cell_prealloc,
530 cell_free_fn free_fn, void *free_context,
531 struct dm_bio_prison_cell **cell_result)
534 struct dm_cell_key key;
536 build_key(oblock_begin, oblock_end, &key);
537 r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result);
539 free_fn(free_context, cell_prealloc);
544 static int bio_detain(struct cache *cache, dm_oblock_t oblock,
545 struct bio *bio, struct dm_bio_prison_cell *cell_prealloc,
546 cell_free_fn free_fn, void *free_context,
547 struct dm_bio_prison_cell **cell_result)
549 dm_oblock_t end = to_oblock(from_oblock(oblock) + 1ULL);
550 return bio_detain_range(cache, oblock, end, bio,
551 cell_prealloc, free_fn, free_context, cell_result);
554 static int get_cell(struct cache *cache,
556 struct prealloc *structs,
557 struct dm_bio_prison_cell **cell_result)
560 struct dm_cell_key key;
561 struct dm_bio_prison_cell *cell_prealloc;
563 cell_prealloc = prealloc_get_cell(structs);
565 build_key(oblock, to_oblock(from_oblock(oblock) + 1ULL), &key);
566 r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result);
568 prealloc_put_cell(structs, cell_prealloc);
573 /*----------------------------------------------------------------*/
575 static bool is_dirty(struct cache *cache, dm_cblock_t b)
577 return test_bit(from_cblock(b), cache->dirty_bitset);
580 static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
582 if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) {
583 atomic_inc(&cache->nr_dirty);
584 policy_set_dirty(cache->policy, oblock);
588 static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
590 if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) {
591 policy_clear_dirty(cache->policy, oblock);
592 if (atomic_dec_return(&cache->nr_dirty) == 0)
593 dm_table_event(cache->ti->table);
597 /*----------------------------------------------------------------*/
599 static bool block_size_is_power_of_two(struct cache *cache)
601 return cache->sectors_per_block_shift >= 0;
604 /* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */
605 #if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6
608 static dm_block_t block_div(dm_block_t b, uint32_t n)
615 static dm_block_t oblocks_per_dblock(struct cache *cache)
617 dm_block_t oblocks = cache->discard_block_size;
619 if (block_size_is_power_of_two(cache))
620 oblocks >>= cache->sectors_per_block_shift;
622 oblocks = block_div(oblocks, cache->sectors_per_block);
627 static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock)
629 return to_dblock(block_div(from_oblock(oblock),
630 oblocks_per_dblock(cache)));
633 static dm_oblock_t dblock_to_oblock(struct cache *cache, dm_dblock_t dblock)
635 return to_oblock(from_dblock(dblock) * oblocks_per_dblock(cache));
638 static void set_discard(struct cache *cache, dm_dblock_t b)
642 BUG_ON(from_dblock(b) >= from_dblock(cache->discard_nr_blocks));
643 atomic_inc(&cache->stats.discard_count);
645 spin_lock_irqsave(&cache->lock, flags);
646 set_bit(from_dblock(b), cache->discard_bitset);
647 spin_unlock_irqrestore(&cache->lock, flags);
650 static void clear_discard(struct cache *cache, dm_dblock_t b)
654 spin_lock_irqsave(&cache->lock, flags);
655 clear_bit(from_dblock(b), cache->discard_bitset);
656 spin_unlock_irqrestore(&cache->lock, flags);
659 static bool is_discarded(struct cache *cache, dm_dblock_t b)
664 spin_lock_irqsave(&cache->lock, flags);
665 r = test_bit(from_dblock(b), cache->discard_bitset);
666 spin_unlock_irqrestore(&cache->lock, flags);
671 static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b)
676 spin_lock_irqsave(&cache->lock, flags);
677 r = test_bit(from_dblock(oblock_to_dblock(cache, b)),
678 cache->discard_bitset);
679 spin_unlock_irqrestore(&cache->lock, flags);
684 /*----------------------------------------------------------------*/
686 static void load_stats(struct cache *cache)
688 struct dm_cache_statistics stats;
690 dm_cache_metadata_get_stats(cache->cmd, &stats);
691 atomic_set(&cache->stats.read_hit, stats.read_hits);
692 atomic_set(&cache->stats.read_miss, stats.read_misses);
693 atomic_set(&cache->stats.write_hit, stats.write_hits);
694 atomic_set(&cache->stats.write_miss, stats.write_misses);
697 static void save_stats(struct cache *cache)
699 struct dm_cache_statistics stats;
701 if (get_cache_mode(cache) >= CM_READ_ONLY)
704 stats.read_hits = atomic_read(&cache->stats.read_hit);
705 stats.read_misses = atomic_read(&cache->stats.read_miss);
706 stats.write_hits = atomic_read(&cache->stats.write_hit);
707 stats.write_misses = atomic_read(&cache->stats.write_miss);
709 dm_cache_metadata_set_stats(cache->cmd, &stats);
712 /*----------------------------------------------------------------
714 *--------------------------------------------------------------*/
717 * If using writeback, leave out struct per_bio_data's writethrough fields.
719 #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache))
720 #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data))
722 static bool writethrough_mode(struct cache_features *f)
724 return f->io_mode == CM_IO_WRITETHROUGH;
727 static bool writeback_mode(struct cache_features *f)
729 return f->io_mode == CM_IO_WRITEBACK;
732 static bool passthrough_mode(struct cache_features *f)
734 return f->io_mode == CM_IO_PASSTHROUGH;
737 static size_t get_per_bio_data_size(struct cache *cache)
739 return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB;
742 static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size)
744 struct per_bio_data *pb = dm_per_bio_data(bio, data_size);
749 static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size)
751 struct per_bio_data *pb = get_per_bio_data(bio, data_size);
754 pb->req_nr = dm_bio_get_target_bio_nr(bio);
755 pb->all_io_entry = NULL;
761 /*----------------------------------------------------------------
763 *--------------------------------------------------------------*/
764 static void remap_to_origin(struct cache *cache, struct bio *bio)
766 bio->bi_bdev = cache->origin_dev->bdev;
769 static void remap_to_cache(struct cache *cache, struct bio *bio,
772 sector_t bi_sector = bio->bi_iter.bi_sector;
773 sector_t block = from_cblock(cblock);
775 bio->bi_bdev = cache->cache_dev->bdev;
776 if (!block_size_is_power_of_two(cache))
777 bio->bi_iter.bi_sector =
778 (block * cache->sectors_per_block) +
779 sector_div(bi_sector, cache->sectors_per_block);
781 bio->bi_iter.bi_sector =
782 (block << cache->sectors_per_block_shift) |
783 (bi_sector & (cache->sectors_per_block - 1));
786 static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)
789 size_t pb_data_size = get_per_bio_data_size(cache);
790 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
792 spin_lock_irqsave(&cache->lock, flags);
793 if (cache->need_tick_bio &&
794 !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) {
796 cache->need_tick_bio = false;
798 spin_unlock_irqrestore(&cache->lock, flags);
801 static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio,
804 check_if_tick_bio_needed(cache, bio);
805 remap_to_origin(cache, bio);
806 if (bio_data_dir(bio) == WRITE)
807 clear_discard(cache, oblock_to_dblock(cache, oblock));
810 static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
811 dm_oblock_t oblock, dm_cblock_t cblock)
813 check_if_tick_bio_needed(cache, bio);
814 remap_to_cache(cache, bio, cblock);
815 if (bio_data_dir(bio) == WRITE) {
816 set_dirty(cache, oblock, cblock);
817 clear_discard(cache, oblock_to_dblock(cache, oblock));
821 static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio)
823 sector_t block_nr = bio->bi_iter.bi_sector;
825 if (!block_size_is_power_of_two(cache))
826 (void) sector_div(block_nr, cache->sectors_per_block);
828 block_nr >>= cache->sectors_per_block_shift;
830 return to_oblock(block_nr);
833 static int bio_triggers_commit(struct cache *cache, struct bio *bio)
835 return bio->bi_rw & (REQ_FLUSH | REQ_FUA);
839 * You must increment the deferred set whilst the prison cell is held. To
840 * encourage this, we ask for 'cell' to be passed in.
842 static void inc_ds(struct cache *cache, struct bio *bio,
843 struct dm_bio_prison_cell *cell)
845 size_t pb_data_size = get_per_bio_data_size(cache);
846 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
849 BUG_ON(pb->all_io_entry);
851 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
854 static bool accountable_bio(struct cache *cache, struct bio *bio)
856 return ((bio->bi_bdev == cache->origin_dev->bdev) &&
857 !(bio->bi_rw & REQ_DISCARD));
860 static void accounted_begin(struct cache *cache, struct bio *bio)
862 size_t pb_data_size = get_per_bio_data_size(cache);
863 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
865 if (accountable_bio(cache, bio)) {
866 pb->len = bio_sectors(bio);
867 iot_io_begin(&cache->origin_tracker, pb->len);
871 static void accounted_complete(struct cache *cache, struct bio *bio)
873 size_t pb_data_size = get_per_bio_data_size(cache);
874 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
876 iot_io_end(&cache->origin_tracker, pb->len);
879 static void accounted_request(struct cache *cache, struct bio *bio)
881 accounted_begin(cache, bio);
882 generic_make_request(bio);
885 static void issue(struct cache *cache, struct bio *bio)
889 if (!bio_triggers_commit(cache, bio)) {
890 accounted_request(cache, bio);
895 * Batch together any bios that trigger commits and then issue a
896 * single commit for them in do_worker().
898 spin_lock_irqsave(&cache->lock, flags);
899 cache->commit_requested = true;
900 bio_list_add(&cache->deferred_flush_bios, bio);
901 spin_unlock_irqrestore(&cache->lock, flags);
904 static void inc_and_issue(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell *cell)
906 inc_ds(cache, bio, cell);
910 static void defer_writethrough_bio(struct cache *cache, struct bio *bio)
914 spin_lock_irqsave(&cache->lock, flags);
915 bio_list_add(&cache->deferred_writethrough_bios, bio);
916 spin_unlock_irqrestore(&cache->lock, flags);
921 static void writethrough_endio(struct bio *bio, int err)
923 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
925 dm_unhook_bio(&pb->hook_info, bio);
932 dm_bio_restore(&pb->bio_details, bio);
933 remap_to_cache(pb->cache, bio, pb->cblock);
936 * We can't issue this bio directly, since we're in interrupt
937 * context. So it gets put on a bio list for processing by the
940 defer_writethrough_bio(pb->cache, bio);
944 * When running in writethrough mode we need to send writes to clean blocks
945 * to both the cache and origin devices. In future we'd like to clone the
946 * bio and send them in parallel, but for now we're doing them in
947 * series as this is easier.
949 static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio,
950 dm_oblock_t oblock, dm_cblock_t cblock)
952 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
956 dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL);
957 dm_bio_record(&pb->bio_details, bio);
959 remap_to_origin_clear_discard(pb->cache, bio, oblock);
962 /*----------------------------------------------------------------
964 *--------------------------------------------------------------*/
965 static enum cache_metadata_mode get_cache_mode(struct cache *cache)
967 return cache->features.mode;
970 static const char *cache_device_name(struct cache *cache)
972 return dm_device_name(dm_table_get_md(cache->ti->table));
975 static void notify_mode_switch(struct cache *cache, enum cache_metadata_mode mode)
977 const char *descs[] = {
983 dm_table_event(cache->ti->table);
984 DMINFO("%s: switching cache to %s mode",
985 cache_device_name(cache), descs[(int)mode]);
988 static void set_cache_mode(struct cache *cache, enum cache_metadata_mode new_mode)
990 bool needs_check = dm_cache_metadata_needs_check(cache->cmd);
991 enum cache_metadata_mode old_mode = get_cache_mode(cache);
993 if (new_mode == CM_WRITE && needs_check) {
994 DMERR("%s: unable to switch cache to write mode until repaired.",
995 cache_device_name(cache));
996 if (old_mode != new_mode)
999 new_mode = CM_READ_ONLY;
1002 /* Never move out of fail mode */
1003 if (old_mode == CM_FAIL)
1009 dm_cache_metadata_set_read_only(cache->cmd);
1013 dm_cache_metadata_set_read_write(cache->cmd);
1017 cache->features.mode = new_mode;
1019 if (new_mode != old_mode)
1020 notify_mode_switch(cache, new_mode);
1023 static void abort_transaction(struct cache *cache)
1025 const char *dev_name = cache_device_name(cache);
1027 if (get_cache_mode(cache) >= CM_READ_ONLY)
1030 if (dm_cache_metadata_set_needs_check(cache->cmd)) {
1031 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
1032 set_cache_mode(cache, CM_FAIL);
1035 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
1036 if (dm_cache_metadata_abort(cache->cmd)) {
1037 DMERR("%s: failed to abort metadata transaction", dev_name);
1038 set_cache_mode(cache, CM_FAIL);
1042 static void metadata_operation_failed(struct cache *cache, const char *op, int r)
1044 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
1045 cache_device_name(cache), op, r);
1046 abort_transaction(cache);
1047 set_cache_mode(cache, CM_READ_ONLY);
1050 /*----------------------------------------------------------------
1051 * Migration processing
1053 * Migration covers moving data from the origin device to the cache, or
1055 *--------------------------------------------------------------*/
1056 static void inc_io_migrations(struct cache *cache)
1058 atomic_inc(&cache->nr_io_migrations);
1061 static void dec_io_migrations(struct cache *cache)
1063 atomic_dec(&cache->nr_io_migrations);
1066 static void __cell_release(struct cache *cache, struct dm_bio_prison_cell *cell,
1067 bool holder, struct bio_list *bios)
1069 (holder ? dm_cell_release : dm_cell_release_no_holder)
1070 (cache->prison, cell, bios);
1071 free_prison_cell(cache, cell);
1074 static bool discard_or_flush(struct bio *bio)
1076 return bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD);
1079 static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell)
1081 if (discard_or_flush(cell->holder))
1083 * We have to handle these bios
1086 __cell_release(cache, cell, true, &cache->deferred_bios);
1089 list_add_tail(&cell->user_list, &cache->deferred_cells);
1092 static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, bool holder)
1094 unsigned long flags;
1096 if (!holder && dm_cell_promote_or_release(cache->prison, cell)) {
1098 * There was no prisoner to promote to holder, the
1099 * cell has been released.
1101 free_prison_cell(cache, cell);
1105 spin_lock_irqsave(&cache->lock, flags);
1106 __cell_defer(cache, cell);
1107 spin_unlock_irqrestore(&cache->lock, flags);
1112 static void cell_error_with_code(struct cache *cache, struct dm_bio_prison_cell *cell, int err)
1114 dm_cell_error(cache->prison, cell, err);
1115 dm_bio_prison_free_cell(cache->prison, cell);
1118 static void cell_requeue(struct cache *cache, struct dm_bio_prison_cell *cell)
1120 cell_error_with_code(cache, cell, DM_ENDIO_REQUEUE);
1123 static void free_io_migration(struct dm_cache_migration *mg)
1125 dec_io_migrations(mg->cache);
1129 static void migration_failure(struct dm_cache_migration *mg)
1131 struct cache *cache = mg->cache;
1132 const char *dev_name = cache_device_name(cache);
1134 if (mg->writeback) {
1135 DMERR_LIMIT("%s: writeback failed; couldn't copy block", dev_name);
1136 set_dirty(cache, mg->old_oblock, mg->cblock);
1137 cell_defer(cache, mg->old_ocell, false);
1139 } else if (mg->demote) {
1140 DMERR_LIMIT("%s: demotion failed; couldn't copy block", dev_name);
1141 policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock);
1143 cell_defer(cache, mg->old_ocell, mg->promote ? false : true);
1145 cell_defer(cache, mg->new_ocell, true);
1147 DMERR_LIMIT("%s: promotion failed; couldn't copy block", dev_name);
1148 policy_remove_mapping(cache->policy, mg->new_oblock);
1149 cell_defer(cache, mg->new_ocell, true);
1152 free_io_migration(mg);
1155 static void migration_success_pre_commit(struct dm_cache_migration *mg)
1158 unsigned long flags;
1159 struct cache *cache = mg->cache;
1161 if (mg->writeback) {
1162 clear_dirty(cache, mg->old_oblock, mg->cblock);
1163 cell_defer(cache, mg->old_ocell, false);
1164 free_io_migration(mg);
1167 } else if (mg->demote) {
1168 r = dm_cache_remove_mapping(cache->cmd, mg->cblock);
1170 DMERR_LIMIT("%s: demotion failed; couldn't update on disk metadata",
1171 cache_device_name(cache));
1172 metadata_operation_failed(cache, "dm_cache_remove_mapping", r);
1173 policy_force_mapping(cache->policy, mg->new_oblock,
1176 cell_defer(cache, mg->new_ocell, true);
1177 free_io_migration(mg);
1181 r = dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock);
1183 DMERR_LIMIT("%s: promotion failed; couldn't update on disk metadata",
1184 cache_device_name(cache));
1185 metadata_operation_failed(cache, "dm_cache_insert_mapping", r);
1186 policy_remove_mapping(cache->policy, mg->new_oblock);
1187 free_io_migration(mg);
1192 spin_lock_irqsave(&cache->lock, flags);
1193 list_add_tail(&mg->list, &cache->need_commit_migrations);
1194 cache->commit_requested = true;
1195 spin_unlock_irqrestore(&cache->lock, flags);
1198 static void migration_success_post_commit(struct dm_cache_migration *mg)
1200 unsigned long flags;
1201 struct cache *cache = mg->cache;
1203 if (mg->writeback) {
1204 DMWARN_LIMIT("%s: writeback unexpectedly triggered commit",
1205 cache_device_name(cache));
1208 } else if (mg->demote) {
1209 cell_defer(cache, mg->old_ocell, mg->promote ? false : true);
1214 spin_lock_irqsave(&cache->lock, flags);
1215 list_add_tail(&mg->list, &cache->quiesced_migrations);
1216 spin_unlock_irqrestore(&cache->lock, flags);
1220 policy_remove_mapping(cache->policy, mg->old_oblock);
1221 free_io_migration(mg);
1225 if (mg->requeue_holder) {
1226 clear_dirty(cache, mg->new_oblock, mg->cblock);
1227 cell_defer(cache, mg->new_ocell, true);
1230 * The block was promoted via an overwrite, so it's dirty.
1232 set_dirty(cache, mg->new_oblock, mg->cblock);
1233 bio_endio(mg->new_ocell->holder, 0);
1234 cell_defer(cache, mg->new_ocell, false);
1236 free_io_migration(mg);
1240 static void copy_complete(int read_err, unsigned long write_err, void *context)
1242 unsigned long flags;
1243 struct dm_cache_migration *mg = (struct dm_cache_migration *) context;
1244 struct cache *cache = mg->cache;
1246 if (read_err || write_err)
1249 spin_lock_irqsave(&cache->lock, flags);
1250 list_add_tail(&mg->list, &cache->completed_migrations);
1251 spin_unlock_irqrestore(&cache->lock, flags);
1256 static void issue_copy(struct dm_cache_migration *mg)
1259 struct dm_io_region o_region, c_region;
1260 struct cache *cache = mg->cache;
1261 sector_t cblock = from_cblock(mg->cblock);
1263 o_region.bdev = cache->origin_dev->bdev;
1264 o_region.count = cache->sectors_per_block;
1266 c_region.bdev = cache->cache_dev->bdev;
1267 c_region.sector = cblock * cache->sectors_per_block;
1268 c_region.count = cache->sectors_per_block;
1270 if (mg->writeback || mg->demote) {
1272 o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block;
1273 r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg);
1276 o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block;
1277 r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg);
1281 DMERR_LIMIT("%s: issuing migration failed", cache_device_name(cache));
1282 migration_failure(mg);
1286 static void overwrite_endio(struct bio *bio, int err)
1288 struct dm_cache_migration *mg = bio->bi_private;
1289 struct cache *cache = mg->cache;
1290 size_t pb_data_size = get_per_bio_data_size(cache);
1291 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1292 unsigned long flags;
1294 dm_unhook_bio(&pb->hook_info, bio);
1299 mg->requeue_holder = false;
1301 spin_lock_irqsave(&cache->lock, flags);
1302 list_add_tail(&mg->list, &cache->completed_migrations);
1303 spin_unlock_irqrestore(&cache->lock, flags);
1308 static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio)
1310 size_t pb_data_size = get_per_bio_data_size(mg->cache);
1311 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1313 dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg);
1314 remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock);
1317 * No need to inc_ds() here, since the cell will be held for the
1318 * duration of the io.
1320 accounted_request(mg->cache, bio);
1323 static bool bio_writes_complete_block(struct cache *cache, struct bio *bio)
1325 return (bio_data_dir(bio) == WRITE) &&
1326 (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT));
1329 static void avoid_copy(struct dm_cache_migration *mg)
1331 atomic_inc(&mg->cache->stats.copies_avoided);
1332 migration_success_pre_commit(mg);
1335 static void calc_discard_block_range(struct cache *cache, struct bio *bio,
1336 dm_dblock_t *b, dm_dblock_t *e)
1338 sector_t sb = bio->bi_iter.bi_sector;
1339 sector_t se = bio_end_sector(bio);
1341 *b = to_dblock(dm_sector_div_up(sb, cache->discard_block_size));
1343 if (se - sb < cache->discard_block_size)
1346 *e = to_dblock(block_div(se, cache->discard_block_size));
1349 static void issue_discard(struct dm_cache_migration *mg)
1352 struct bio *bio = mg->new_ocell->holder;
1354 calc_discard_block_range(mg->cache, bio, &b, &e);
1356 set_discard(mg->cache, b);
1357 b = to_dblock(from_dblock(b) + 1);
1361 cell_defer(mg->cache, mg->new_ocell, false);
1365 static void issue_copy_or_discard(struct dm_cache_migration *mg)
1368 struct cache *cache = mg->cache;
1375 if (mg->writeback || mg->demote)
1376 avoid = !is_dirty(cache, mg->cblock) ||
1377 is_discarded_oblock(cache, mg->old_oblock);
1379 struct bio *bio = mg->new_ocell->holder;
1381 avoid = is_discarded_oblock(cache, mg->new_oblock);
1383 if (writeback_mode(&cache->features) &&
1384 !avoid && bio_writes_complete_block(cache, bio)) {
1385 issue_overwrite(mg, bio);
1390 avoid ? avoid_copy(mg) : issue_copy(mg);
1393 static void complete_migration(struct dm_cache_migration *mg)
1396 migration_failure(mg);
1398 migration_success_pre_commit(mg);
1401 static void process_migrations(struct cache *cache, struct list_head *head,
1402 void (*fn)(struct dm_cache_migration *))
1404 unsigned long flags;
1405 struct list_head list;
1406 struct dm_cache_migration *mg, *tmp;
1408 INIT_LIST_HEAD(&list);
1409 spin_lock_irqsave(&cache->lock, flags);
1410 list_splice_init(head, &list);
1411 spin_unlock_irqrestore(&cache->lock, flags);
1413 list_for_each_entry_safe(mg, tmp, &list, list)
1417 static void __queue_quiesced_migration(struct dm_cache_migration *mg)
1419 list_add_tail(&mg->list, &mg->cache->quiesced_migrations);
1422 static void queue_quiesced_migration(struct dm_cache_migration *mg)
1424 unsigned long flags;
1425 struct cache *cache = mg->cache;
1427 spin_lock_irqsave(&cache->lock, flags);
1428 __queue_quiesced_migration(mg);
1429 spin_unlock_irqrestore(&cache->lock, flags);
1434 static void queue_quiesced_migrations(struct cache *cache, struct list_head *work)
1436 unsigned long flags;
1437 struct dm_cache_migration *mg, *tmp;
1439 spin_lock_irqsave(&cache->lock, flags);
1440 list_for_each_entry_safe(mg, tmp, work, list)
1441 __queue_quiesced_migration(mg);
1442 spin_unlock_irqrestore(&cache->lock, flags);
1447 static void check_for_quiesced_migrations(struct cache *cache,
1448 struct per_bio_data *pb)
1450 struct list_head work;
1452 if (!pb->all_io_entry)
1455 INIT_LIST_HEAD(&work);
1456 dm_deferred_entry_dec(pb->all_io_entry, &work);
1458 if (!list_empty(&work))
1459 queue_quiesced_migrations(cache, &work);
1462 static void quiesce_migration(struct dm_cache_migration *mg)
1464 if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list))
1465 queue_quiesced_migration(mg);
1468 static void promote(struct cache *cache, struct prealloc *structs,
1469 dm_oblock_t oblock, dm_cblock_t cblock,
1470 struct dm_bio_prison_cell *cell)
1472 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1475 mg->discard = false;
1476 mg->writeback = false;
1479 mg->requeue_holder = true;
1480 mg->invalidate = false;
1482 mg->new_oblock = oblock;
1483 mg->cblock = cblock;
1484 mg->old_ocell = NULL;
1485 mg->new_ocell = cell;
1486 mg->start_jiffies = jiffies;
1488 inc_io_migrations(cache);
1489 quiesce_migration(mg);
1492 static void writeback(struct cache *cache, struct prealloc *structs,
1493 dm_oblock_t oblock, dm_cblock_t cblock,
1494 struct dm_bio_prison_cell *cell)
1496 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1499 mg->discard = false;
1500 mg->writeback = true;
1502 mg->promote = false;
1503 mg->requeue_holder = true;
1504 mg->invalidate = false;
1506 mg->old_oblock = oblock;
1507 mg->cblock = cblock;
1508 mg->old_ocell = cell;
1509 mg->new_ocell = NULL;
1510 mg->start_jiffies = jiffies;
1512 inc_io_migrations(cache);
1513 quiesce_migration(mg);
1516 static void demote_then_promote(struct cache *cache, struct prealloc *structs,
1517 dm_oblock_t old_oblock, dm_oblock_t new_oblock,
1519 struct dm_bio_prison_cell *old_ocell,
1520 struct dm_bio_prison_cell *new_ocell)
1522 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1525 mg->discard = false;
1526 mg->writeback = false;
1529 mg->requeue_holder = true;
1530 mg->invalidate = false;
1532 mg->old_oblock = old_oblock;
1533 mg->new_oblock = new_oblock;
1534 mg->cblock = cblock;
1535 mg->old_ocell = old_ocell;
1536 mg->new_ocell = new_ocell;
1537 mg->start_jiffies = jiffies;
1539 inc_io_migrations(cache);
1540 quiesce_migration(mg);
1544 * Invalidate a cache entry. No writeback occurs; any changes in the cache
1545 * block are thrown away.
1547 static void invalidate(struct cache *cache, struct prealloc *structs,
1548 dm_oblock_t oblock, dm_cblock_t cblock,
1549 struct dm_bio_prison_cell *cell)
1551 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1554 mg->discard = false;
1555 mg->writeback = false;
1557 mg->promote = false;
1558 mg->requeue_holder = true;
1559 mg->invalidate = true;
1561 mg->old_oblock = oblock;
1562 mg->cblock = cblock;
1563 mg->old_ocell = cell;
1564 mg->new_ocell = NULL;
1565 mg->start_jiffies = jiffies;
1567 inc_io_migrations(cache);
1568 quiesce_migration(mg);
1571 static void discard(struct cache *cache, struct prealloc *structs,
1572 struct dm_bio_prison_cell *cell)
1574 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1578 mg->writeback = false;
1580 mg->promote = false;
1581 mg->requeue_holder = false;
1582 mg->invalidate = false;
1584 mg->old_ocell = NULL;
1585 mg->new_ocell = cell;
1586 mg->start_jiffies = jiffies;
1588 quiesce_migration(mg);
1591 /*----------------------------------------------------------------
1593 *--------------------------------------------------------------*/
1594 static void defer_bio(struct cache *cache, struct bio *bio)
1596 unsigned long flags;
1598 spin_lock_irqsave(&cache->lock, flags);
1599 bio_list_add(&cache->deferred_bios, bio);
1600 spin_unlock_irqrestore(&cache->lock, flags);
1605 static void process_flush_bio(struct cache *cache, struct bio *bio)
1607 size_t pb_data_size = get_per_bio_data_size(cache);
1608 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1610 BUG_ON(bio->bi_iter.bi_size);
1612 remap_to_origin(cache, bio);
1614 remap_to_cache(cache, bio, 0);
1617 * REQ_FLUSH is not directed at any particular block so we don't
1618 * need to inc_ds(). REQ_FUA's are split into a write + REQ_FLUSH
1624 static void process_discard_bio(struct cache *cache, struct prealloc *structs,
1629 struct dm_bio_prison_cell *cell_prealloc, *new_ocell;
1631 calc_discard_block_range(cache, bio, &b, &e);
1637 cell_prealloc = prealloc_get_cell(structs);
1638 r = bio_detain_range(cache, dblock_to_oblock(cache, b), dblock_to_oblock(cache, e), bio, cell_prealloc,
1639 (cell_free_fn) prealloc_put_cell,
1640 structs, &new_ocell);
1644 discard(cache, structs, new_ocell);
1647 static bool spare_migration_bandwidth(struct cache *cache)
1649 sector_t current_volume = (atomic_read(&cache->nr_io_migrations) + 1) *
1650 cache->sectors_per_block;
1651 return current_volume < cache->migration_threshold;
1654 static void inc_hit_counter(struct cache *cache, struct bio *bio)
1656 atomic_inc(bio_data_dir(bio) == READ ?
1657 &cache->stats.read_hit : &cache->stats.write_hit);
1660 static void inc_miss_counter(struct cache *cache, struct bio *bio)
1662 atomic_inc(bio_data_dir(bio) == READ ?
1663 &cache->stats.read_miss : &cache->stats.write_miss);
1666 /*----------------------------------------------------------------*/
1669 struct cache *cache;
1670 struct bio_list bios_for_issue;
1671 struct bio_list unhandled_bios;
1675 static void inc_fn(void *context, struct dm_bio_prison_cell *cell)
1678 struct inc_detail *detail = context;
1679 struct cache *cache = detail->cache;
1681 inc_ds(cache, cell->holder, cell);
1682 if (bio_data_dir(cell->holder) == WRITE)
1683 detail->any_writes = true;
1685 while ((bio = bio_list_pop(&cell->bios))) {
1686 if (discard_or_flush(bio)) {
1687 bio_list_add(&detail->unhandled_bios, bio);
1691 if (bio_data_dir(bio) == WRITE)
1692 detail->any_writes = true;
1694 bio_list_add(&detail->bios_for_issue, bio);
1695 inc_ds(cache, bio, cell);
1699 // FIXME: refactor these two
1700 static void remap_cell_to_origin_clear_discard(struct cache *cache,
1701 struct dm_bio_prison_cell *cell,
1702 dm_oblock_t oblock, bool issue_holder)
1705 unsigned long flags;
1706 struct inc_detail detail;
1708 detail.cache = cache;
1709 bio_list_init(&detail.bios_for_issue);
1710 bio_list_init(&detail.unhandled_bios);
1711 detail.any_writes = false;
1713 spin_lock_irqsave(&cache->lock, flags);
1714 dm_cell_visit_release(cache->prison, inc_fn, &detail, cell);
1715 bio_list_merge(&cache->deferred_bios, &detail.unhandled_bios);
1716 spin_unlock_irqrestore(&cache->lock, flags);
1718 remap_to_origin(cache, cell->holder);
1720 issue(cache, cell->holder);
1722 accounted_begin(cache, cell->holder);
1724 if (detail.any_writes)
1725 clear_discard(cache, oblock_to_dblock(cache, oblock));
1727 while ((bio = bio_list_pop(&detail.bios_for_issue))) {
1728 remap_to_origin(cache, bio);
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);
1767 /*----------------------------------------------------------------*/
1769 struct old_oblock_lock {
1770 struct policy_locker locker;
1771 struct cache *cache;
1772 struct prealloc *structs;
1773 struct dm_bio_prison_cell *cell;
1776 static int null_locker(struct policy_locker *locker, dm_oblock_t b)
1778 /* This should never be called */
1783 static int cell_locker(struct policy_locker *locker, dm_oblock_t b)
1785 struct old_oblock_lock *l = container_of(locker, struct old_oblock_lock, locker);
1786 struct dm_bio_prison_cell *cell_prealloc = prealloc_get_cell(l->structs);
1788 return bio_detain(l->cache, b, NULL, cell_prealloc,
1789 (cell_free_fn) prealloc_put_cell,
1790 l->structs, &l->cell);
1793 static void process_cell(struct cache *cache, struct prealloc *structs,
1794 struct dm_bio_prison_cell *new_ocell)
1797 bool release_cell = true;
1798 struct bio *bio = new_ocell->holder;
1799 dm_oblock_t block = get_bio_block(cache, bio);
1800 struct policy_result lookup_result;
1801 bool passthrough = passthrough_mode(&cache->features);
1802 bool fast_promotion, can_migrate;
1803 struct old_oblock_lock ool;
1805 fast_promotion = is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio);
1806 can_migrate = !passthrough && (fast_promotion || spare_migration_bandwidth(cache));
1808 ool.locker.fn = cell_locker;
1810 ool.structs = structs;
1812 r = policy_map(cache->policy, block, true, can_migrate, fast_promotion,
1813 bio, &ool.locker, &lookup_result);
1815 if (r == -EWOULDBLOCK)
1816 /* migration has been denied */
1817 lookup_result.op = POLICY_MISS;
1819 switch (lookup_result.op) {
1822 inc_miss_counter(cache, bio);
1825 * Passthrough always maps to the origin,
1826 * invalidating any cache blocks that are written
1830 if (bio_data_dir(bio) == WRITE) {
1831 atomic_inc(&cache->stats.demotion);
1832 invalidate(cache, structs, block, lookup_result.cblock, new_ocell);
1833 release_cell = false;
1836 /* FIXME: factor out issue_origin() */
1837 remap_to_origin_clear_discard(cache, bio, block);
1838 inc_and_issue(cache, bio, new_ocell);
1841 inc_hit_counter(cache, bio);
1843 if (bio_data_dir(bio) == WRITE &&
1844 writethrough_mode(&cache->features) &&
1845 !is_dirty(cache, lookup_result.cblock)) {
1846 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
1847 inc_and_issue(cache, bio, new_ocell);
1850 remap_cell_to_cache_dirty(cache, new_ocell, block, lookup_result.cblock, true);
1851 release_cell = false;
1858 inc_miss_counter(cache, bio);
1859 remap_cell_to_origin_clear_discard(cache, new_ocell, block, true);
1860 release_cell = false;
1864 atomic_inc(&cache->stats.promotion);
1865 promote(cache, structs, block, lookup_result.cblock, new_ocell);
1866 release_cell = false;
1869 case POLICY_REPLACE:
1870 atomic_inc(&cache->stats.demotion);
1871 atomic_inc(&cache->stats.promotion);
1872 demote_then_promote(cache, structs, lookup_result.old_oblock,
1873 block, lookup_result.cblock,
1874 ool.cell, new_ocell);
1875 release_cell = false;
1879 DMERR_LIMIT("%s: %s: erroring bio, unknown policy op: %u",
1880 cache_device_name(cache), __func__,
1881 (unsigned) lookup_result.op);
1886 cell_defer(cache, new_ocell, false);
1889 static void process_bio(struct cache *cache, struct prealloc *structs,
1893 dm_oblock_t block = get_bio_block(cache, bio);
1894 struct dm_bio_prison_cell *cell_prealloc, *new_ocell;
1897 * Check to see if that block is currently migrating.
1899 cell_prealloc = prealloc_get_cell(structs);
1900 r = bio_detain(cache, block, bio, cell_prealloc,
1901 (cell_free_fn) prealloc_put_cell,
1902 structs, &new_ocell);
1906 process_cell(cache, structs, new_ocell);
1909 static int need_commit_due_to_time(struct cache *cache)
1911 return jiffies < cache->last_commit_jiffies ||
1912 jiffies > cache->last_commit_jiffies + COMMIT_PERIOD;
1916 * A non-zero return indicates read_only or fail_io mode.
1918 static int commit(struct cache *cache, bool clean_shutdown)
1922 if (get_cache_mode(cache) >= CM_READ_ONLY)
1925 atomic_inc(&cache->stats.commit_count);
1926 r = dm_cache_commit(cache->cmd, clean_shutdown);
1928 metadata_operation_failed(cache, "dm_cache_commit", r);
1933 static int commit_if_needed(struct cache *cache)
1937 if ((cache->commit_requested || need_commit_due_to_time(cache)) &&
1938 dm_cache_changed_this_transaction(cache->cmd)) {
1939 r = commit(cache, false);
1940 cache->commit_requested = false;
1941 cache->last_commit_jiffies = jiffies;
1947 static void process_deferred_bios(struct cache *cache)
1949 unsigned long flags;
1950 struct bio_list bios;
1952 struct prealloc structs;
1954 memset(&structs, 0, sizeof(structs));
1955 bio_list_init(&bios);
1957 spin_lock_irqsave(&cache->lock, flags);
1958 bio_list_merge(&bios, &cache->deferred_bios);
1959 bio_list_init(&cache->deferred_bios);
1960 spin_unlock_irqrestore(&cache->lock, flags);
1962 while (!bio_list_empty(&bios)) {
1964 * If we've got no free migration structs, and processing
1965 * this bio might require one, we pause until there are some
1966 * prepared mappings to process.
1968 if (prealloc_data_structs(cache, &structs)) {
1969 spin_lock_irqsave(&cache->lock, flags);
1970 bio_list_merge(&cache->deferred_bios, &bios);
1971 spin_unlock_irqrestore(&cache->lock, flags);
1975 bio = bio_list_pop(&bios);
1977 if (bio->bi_rw & REQ_FLUSH)
1978 process_flush_bio(cache, bio);
1979 else if (bio->bi_rw & REQ_DISCARD)
1980 process_discard_bio(cache, &structs, bio);
1982 process_bio(cache, &structs, bio);
1985 prealloc_free_structs(cache, &structs);
1988 static void process_deferred_cells(struct cache *cache)
1990 unsigned long flags;
1991 struct dm_bio_prison_cell *cell, *tmp;
1992 struct list_head cells;
1993 struct prealloc structs;
1995 memset(&structs, 0, sizeof(structs));
1997 INIT_LIST_HEAD(&cells);
1999 spin_lock_irqsave(&cache->lock, flags);
2000 list_splice_init(&cache->deferred_cells, &cells);
2001 spin_unlock_irqrestore(&cache->lock, flags);
2003 list_for_each_entry_safe(cell, tmp, &cells, user_list) {
2005 * If we've got no free migration structs, and processing
2006 * this bio might require one, we pause until there are some
2007 * prepared mappings to process.
2009 if (prealloc_data_structs(cache, &structs)) {
2010 spin_lock_irqsave(&cache->lock, flags);
2011 list_splice(&cells, &cache->deferred_cells);
2012 spin_unlock_irqrestore(&cache->lock, flags);
2016 process_cell(cache, &structs, cell);
2019 prealloc_free_structs(cache, &structs);
2022 static void process_deferred_flush_bios(struct cache *cache, bool submit_bios)
2024 unsigned long flags;
2025 struct bio_list bios;
2028 bio_list_init(&bios);
2030 spin_lock_irqsave(&cache->lock, flags);
2031 bio_list_merge(&bios, &cache->deferred_flush_bios);
2032 bio_list_init(&cache->deferred_flush_bios);
2033 spin_unlock_irqrestore(&cache->lock, flags);
2036 * These bios have already been through inc_ds()
2038 while ((bio = bio_list_pop(&bios)))
2039 submit_bios ? accounted_request(cache, bio) : bio_io_error(bio);
2042 static void process_deferred_writethrough_bios(struct cache *cache)
2044 unsigned long flags;
2045 struct bio_list bios;
2048 bio_list_init(&bios);
2050 spin_lock_irqsave(&cache->lock, flags);
2051 bio_list_merge(&bios, &cache->deferred_writethrough_bios);
2052 bio_list_init(&cache->deferred_writethrough_bios);
2053 spin_unlock_irqrestore(&cache->lock, flags);
2056 * These bios have already been through inc_ds()
2058 while ((bio = bio_list_pop(&bios)))
2059 accounted_request(cache, bio);
2062 static void writeback_some_dirty_blocks(struct cache *cache)
2066 struct prealloc structs;
2067 struct dm_bio_prison_cell *old_ocell;
2068 bool busy = !iot_idle_for(&cache->origin_tracker, HZ);
2070 memset(&structs, 0, sizeof(structs));
2072 while (spare_migration_bandwidth(cache)) {
2073 if (policy_writeback_work(cache->policy, &oblock, &cblock, busy))
2074 break; /* no work to do */
2076 if (prealloc_data_structs(cache, &structs) ||
2077 get_cell(cache, oblock, &structs, &old_ocell)) {
2078 policy_set_dirty(cache->policy, oblock);
2082 writeback(cache, &structs, oblock, cblock, old_ocell);
2085 prealloc_free_structs(cache, &structs);
2088 /*----------------------------------------------------------------
2090 * Dropping something from the cache *without* writing back.
2091 *--------------------------------------------------------------*/
2093 static void process_invalidation_request(struct cache *cache, struct invalidation_request *req)
2096 uint64_t begin = from_cblock(req->cblocks->begin);
2097 uint64_t end = from_cblock(req->cblocks->end);
2099 while (begin != end) {
2100 r = policy_remove_cblock(cache->policy, to_cblock(begin));
2102 r = dm_cache_remove_mapping(cache->cmd, to_cblock(begin));
2104 metadata_operation_failed(cache, "dm_cache_remove_mapping", r);
2108 } else if (r == -ENODATA) {
2109 /* harmless, already unmapped */
2113 DMERR("%s: policy_remove_cblock failed", cache_device_name(cache));
2120 cache->commit_requested = true;
2123 atomic_set(&req->complete, 1);
2125 wake_up(&req->result_wait);
2128 static void process_invalidation_requests(struct cache *cache)
2130 struct list_head list;
2131 struct invalidation_request *req, *tmp;
2133 INIT_LIST_HEAD(&list);
2134 spin_lock(&cache->invalidation_lock);
2135 list_splice_init(&cache->invalidation_requests, &list);
2136 spin_unlock(&cache->invalidation_lock);
2138 list_for_each_entry_safe (req, tmp, &list, list)
2139 process_invalidation_request(cache, req);
2142 /*----------------------------------------------------------------
2144 *--------------------------------------------------------------*/
2145 static bool is_quiescing(struct cache *cache)
2147 return atomic_read(&cache->quiescing);
2150 static void ack_quiescing(struct cache *cache)
2152 if (is_quiescing(cache)) {
2153 atomic_inc(&cache->quiescing_ack);
2154 wake_up(&cache->quiescing_wait);
2158 static void wait_for_quiescing_ack(struct cache *cache)
2160 wait_event(cache->quiescing_wait, atomic_read(&cache->quiescing_ack));
2163 static void start_quiescing(struct cache *cache)
2165 atomic_inc(&cache->quiescing);
2166 wait_for_quiescing_ack(cache);
2169 static void stop_quiescing(struct cache *cache)
2171 atomic_set(&cache->quiescing, 0);
2172 atomic_set(&cache->quiescing_ack, 0);
2175 static void wait_for_migrations(struct cache *cache)
2177 wait_event(cache->migration_wait, !atomic_read(&cache->nr_allocated_migrations));
2180 static void stop_worker(struct cache *cache)
2182 cancel_delayed_work(&cache->waker);
2183 flush_workqueue(cache->wq);
2186 static void requeue_deferred_cells(struct cache *cache)
2188 unsigned long flags;
2189 struct list_head cells;
2190 struct dm_bio_prison_cell *cell, *tmp;
2192 INIT_LIST_HEAD(&cells);
2193 spin_lock_irqsave(&cache->lock, flags);
2194 list_splice_init(&cache->deferred_cells, &cells);
2195 spin_unlock_irqrestore(&cache->lock, flags);
2197 list_for_each_entry_safe(cell, tmp, &cells, user_list)
2198 cell_requeue(cache, cell);
2201 static void requeue_deferred_bios(struct cache *cache)
2204 struct bio_list bios;
2206 bio_list_init(&bios);
2207 bio_list_merge(&bios, &cache->deferred_bios);
2208 bio_list_init(&cache->deferred_bios);
2210 while ((bio = bio_list_pop(&bios)))
2211 bio_endio(bio, DM_ENDIO_REQUEUE);
2214 static int more_work(struct cache *cache)
2216 if (is_quiescing(cache))
2217 return !list_empty(&cache->quiesced_migrations) ||
2218 !list_empty(&cache->completed_migrations) ||
2219 !list_empty(&cache->need_commit_migrations);
2221 return !bio_list_empty(&cache->deferred_bios) ||
2222 !list_empty(&cache->deferred_cells) ||
2223 !bio_list_empty(&cache->deferred_flush_bios) ||
2224 !bio_list_empty(&cache->deferred_writethrough_bios) ||
2225 !list_empty(&cache->quiesced_migrations) ||
2226 !list_empty(&cache->completed_migrations) ||
2227 !list_empty(&cache->need_commit_migrations) ||
2231 static void do_worker(struct work_struct *ws)
2233 struct cache *cache = container_of(ws, struct cache, worker);
2236 if (!is_quiescing(cache)) {
2237 writeback_some_dirty_blocks(cache);
2238 process_deferred_writethrough_bios(cache);
2239 process_deferred_bios(cache);
2240 process_deferred_cells(cache);
2241 process_invalidation_requests(cache);
2244 process_migrations(cache, &cache->quiesced_migrations, issue_copy_or_discard);
2245 process_migrations(cache, &cache->completed_migrations, complete_migration);
2247 if (commit_if_needed(cache)) {
2248 process_deferred_flush_bios(cache, false);
2249 process_migrations(cache, &cache->need_commit_migrations, migration_failure);
2251 process_deferred_flush_bios(cache, true);
2252 process_migrations(cache, &cache->need_commit_migrations,
2253 migration_success_post_commit);
2256 ack_quiescing(cache);
2258 } while (more_work(cache));
2262 * We want to commit periodically so that not too much
2263 * unwritten metadata builds up.
2265 static void do_waker(struct work_struct *ws)
2267 struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker);
2268 policy_tick(cache->policy, true);
2270 queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD);
2273 /*----------------------------------------------------------------*/
2275 static int is_congested(struct dm_dev *dev, int bdi_bits)
2277 struct request_queue *q = bdev_get_queue(dev->bdev);
2278 return bdi_congested(&q->backing_dev_info, bdi_bits);
2281 static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
2283 struct cache *cache = container_of(cb, struct cache, callbacks);
2285 return is_congested(cache->origin_dev, bdi_bits) ||
2286 is_congested(cache->cache_dev, bdi_bits);
2289 /*----------------------------------------------------------------
2291 *--------------------------------------------------------------*/
2294 * This function gets called on the error paths of the constructor, so we
2295 * have to cope with a partially initialised struct.
2297 static void destroy(struct cache *cache)
2301 if (cache->migration_pool)
2302 mempool_destroy(cache->migration_pool);
2304 if (cache->all_io_ds)
2305 dm_deferred_set_destroy(cache->all_io_ds);
2308 dm_bio_prison_destroy(cache->prison);
2311 destroy_workqueue(cache->wq);
2313 if (cache->dirty_bitset)
2314 free_bitset(cache->dirty_bitset);
2316 if (cache->discard_bitset)
2317 free_bitset(cache->discard_bitset);
2320 dm_kcopyd_client_destroy(cache->copier);
2323 dm_cache_metadata_close(cache->cmd);
2325 if (cache->metadata_dev)
2326 dm_put_device(cache->ti, cache->metadata_dev);
2328 if (cache->origin_dev)
2329 dm_put_device(cache->ti, cache->origin_dev);
2331 if (cache->cache_dev)
2332 dm_put_device(cache->ti, cache->cache_dev);
2335 dm_cache_policy_destroy(cache->policy);
2337 for (i = 0; i < cache->nr_ctr_args ; i++)
2338 kfree(cache->ctr_args[i]);
2339 kfree(cache->ctr_args);
2344 static void cache_dtr(struct dm_target *ti)
2346 struct cache *cache = ti->private;
2351 static sector_t get_dev_size(struct dm_dev *dev)
2353 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
2356 /*----------------------------------------------------------------*/
2359 * Construct a cache device mapping.
2361 * cache <metadata dev> <cache dev> <origin dev> <block size>
2362 * <#feature args> [<feature arg>]*
2363 * <policy> <#policy args> [<policy arg>]*
2365 * metadata dev : fast device holding the persistent metadata
2366 * cache dev : fast device holding cached data blocks
2367 * origin dev : slow device holding original data blocks
2368 * block size : cache unit size in sectors
2370 * #feature args : number of feature arguments passed
2371 * feature args : writethrough. (The default is writeback.)
2373 * policy : the replacement policy to use
2374 * #policy args : an even number of policy arguments corresponding
2375 * to key/value pairs passed to the policy
2376 * policy args : key/value pairs passed to the policy
2377 * E.g. 'sequential_threshold 1024'
2378 * See cache-policies.txt for details.
2380 * Optional feature arguments are:
2381 * writethrough : write through caching that prohibits cache block
2382 * content from being different from origin block content.
2383 * Without this argument, the default behaviour is to write
2384 * back cache block contents later for performance reasons,
2385 * so they may differ from the corresponding origin blocks.
2388 struct dm_target *ti;
2390 struct dm_dev *metadata_dev;
2392 struct dm_dev *cache_dev;
2393 sector_t cache_sectors;
2395 struct dm_dev *origin_dev;
2396 sector_t origin_sectors;
2398 uint32_t block_size;
2400 const char *policy_name;
2402 const char **policy_argv;
2404 struct cache_features features;
2407 static void destroy_cache_args(struct cache_args *ca)
2409 if (ca->metadata_dev)
2410 dm_put_device(ca->ti, ca->metadata_dev);
2413 dm_put_device(ca->ti, ca->cache_dev);
2416 dm_put_device(ca->ti, ca->origin_dev);
2421 static bool at_least_one_arg(struct dm_arg_set *as, char **error)
2424 *error = "Insufficient args";
2431 static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as,
2435 sector_t metadata_dev_size;
2436 char b[BDEVNAME_SIZE];
2438 if (!at_least_one_arg(as, error))
2441 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
2444 *error = "Error opening metadata device";
2448 metadata_dev_size = get_dev_size(ca->metadata_dev);
2449 if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING)
2450 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
2451 bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
2456 static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as,
2461 if (!at_least_one_arg(as, error))
2464 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
2467 *error = "Error opening cache device";
2470 ca->cache_sectors = get_dev_size(ca->cache_dev);
2475 static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as,
2480 if (!at_least_one_arg(as, error))
2483 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
2486 *error = "Error opening origin device";
2490 ca->origin_sectors = get_dev_size(ca->origin_dev);
2491 if (ca->ti->len > ca->origin_sectors) {
2492 *error = "Device size larger than cached device";
2499 static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as,
2502 unsigned long block_size;
2504 if (!at_least_one_arg(as, error))
2507 if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size ||
2508 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
2509 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
2510 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
2511 *error = "Invalid data block size";
2515 if (block_size > ca->cache_sectors) {
2516 *error = "Data block size is larger than the cache device";
2520 ca->block_size = block_size;
2525 static void init_features(struct cache_features *cf)
2527 cf->mode = CM_WRITE;
2528 cf->io_mode = CM_IO_WRITEBACK;
2531 static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
2534 static struct dm_arg _args[] = {
2535 {0, 1, "Invalid number of cache feature arguments"},
2541 struct cache_features *cf = &ca->features;
2545 r = dm_read_arg_group(_args, as, &argc, error);
2550 arg = dm_shift_arg(as);
2552 if (!strcasecmp(arg, "writeback"))
2553 cf->io_mode = CM_IO_WRITEBACK;
2555 else if (!strcasecmp(arg, "writethrough"))
2556 cf->io_mode = CM_IO_WRITETHROUGH;
2558 else if (!strcasecmp(arg, "passthrough"))
2559 cf->io_mode = CM_IO_PASSTHROUGH;
2562 *error = "Unrecognised cache feature requested";
2570 static int parse_policy(struct cache_args *ca, struct dm_arg_set *as,
2573 static struct dm_arg _args[] = {
2574 {0, 1024, "Invalid number of policy arguments"},
2579 if (!at_least_one_arg(as, error))
2582 ca->policy_name = dm_shift_arg(as);
2584 r = dm_read_arg_group(_args, as, &ca->policy_argc, error);
2588 ca->policy_argv = (const char **)as->argv;
2589 dm_consume_args(as, ca->policy_argc);
2594 static int parse_cache_args(struct cache_args *ca, int argc, char **argv,
2598 struct dm_arg_set as;
2603 r = parse_metadata_dev(ca, &as, error);
2607 r = parse_cache_dev(ca, &as, error);
2611 r = parse_origin_dev(ca, &as, error);
2615 r = parse_block_size(ca, &as, error);
2619 r = parse_features(ca, &as, error);
2623 r = parse_policy(ca, &as, error);
2630 /*----------------------------------------------------------------*/
2632 static struct kmem_cache *migration_cache;
2634 #define NOT_CORE_OPTION 1
2636 static int process_config_option(struct cache *cache, const char *key, const char *value)
2640 if (!strcasecmp(key, "migration_threshold")) {
2641 if (kstrtoul(value, 10, &tmp))
2644 cache->migration_threshold = tmp;
2648 return NOT_CORE_OPTION;
2651 static int set_config_value(struct cache *cache, const char *key, const char *value)
2653 int r = process_config_option(cache, key, value);
2655 if (r == NOT_CORE_OPTION)
2656 r = policy_set_config_value(cache->policy, key, value);
2659 DMWARN("bad config value for %s: %s", key, value);
2664 static int set_config_values(struct cache *cache, int argc, const char **argv)
2669 DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs.");
2674 r = set_config_value(cache, argv[0], argv[1]);
2685 static int create_cache_policy(struct cache *cache, struct cache_args *ca,
2688 struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name,
2690 cache->origin_sectors,
2691 cache->sectors_per_block);
2693 *error = "Error creating cache's policy";
2702 * We want the discard block size to be at least the size of the cache
2703 * block size and have no more than 2^14 discard blocks across the origin.
2705 #define MAX_DISCARD_BLOCKS (1 << 14)
2707 static bool too_many_discard_blocks(sector_t discard_block_size,
2708 sector_t origin_size)
2710 (void) sector_div(origin_size, discard_block_size);
2712 return origin_size > MAX_DISCARD_BLOCKS;
2715 static sector_t calculate_discard_block_size(sector_t cache_block_size,
2716 sector_t origin_size)
2718 sector_t discard_block_size = cache_block_size;
2721 while (too_many_discard_blocks(discard_block_size, origin_size))
2722 discard_block_size *= 2;
2724 return discard_block_size;
2727 static void set_cache_size(struct cache *cache, dm_cblock_t size)
2729 dm_block_t nr_blocks = from_cblock(size);
2731 if (nr_blocks > (1 << 20) && cache->cache_size != size)
2732 DMWARN_LIMIT("You have created a cache device with a lot of individual cache blocks (%llu)\n"
2733 "All these mappings can consume a lot of kernel memory, and take some time to read/write.\n"
2734 "Please consider increasing the cache block size to reduce the overall cache block count.",
2735 (unsigned long long) nr_blocks);
2737 cache->cache_size = size;
2740 #define DEFAULT_MIGRATION_THRESHOLD 2048
2742 static int cache_create(struct cache_args *ca, struct cache **result)
2745 char **error = &ca->ti->error;
2746 struct cache *cache;
2747 struct dm_target *ti = ca->ti;
2748 dm_block_t origin_blocks;
2749 struct dm_cache_metadata *cmd;
2750 bool may_format = ca->features.mode == CM_WRITE;
2752 cache = kzalloc(sizeof(*cache), GFP_KERNEL);
2757 ti->private = cache;
2758 ti->num_flush_bios = 2;
2759 ti->flush_supported = true;
2761 ti->num_discard_bios = 1;
2762 ti->discards_supported = true;
2763 ti->discard_zeroes_data_unsupported = true;
2764 ti->split_discard_bios = false;
2766 cache->features = ca->features;
2767 ti->per_bio_data_size = get_per_bio_data_size(cache);
2769 cache->callbacks.congested_fn = cache_is_congested;
2770 dm_table_add_target_callbacks(ti->table, &cache->callbacks);
2772 cache->metadata_dev = ca->metadata_dev;
2773 cache->origin_dev = ca->origin_dev;
2774 cache->cache_dev = ca->cache_dev;
2776 ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL;
2778 /* FIXME: factor out this whole section */
2779 origin_blocks = cache->origin_sectors = ca->origin_sectors;
2780 origin_blocks = block_div(origin_blocks, ca->block_size);
2781 cache->origin_blocks = to_oblock(origin_blocks);
2783 cache->sectors_per_block = ca->block_size;
2784 if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) {
2789 if (ca->block_size & (ca->block_size - 1)) {
2790 dm_block_t cache_size = ca->cache_sectors;
2792 cache->sectors_per_block_shift = -1;
2793 cache_size = block_div(cache_size, ca->block_size);
2794 set_cache_size(cache, to_cblock(cache_size));
2796 cache->sectors_per_block_shift = __ffs(ca->block_size);
2797 set_cache_size(cache, to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift));
2800 r = create_cache_policy(cache, ca, error);
2804 cache->policy_nr_args = ca->policy_argc;
2805 cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD;
2807 r = set_config_values(cache, ca->policy_argc, ca->policy_argv);
2809 *error = "Error setting cache policy's config values";
2813 cmd = dm_cache_metadata_open(cache->metadata_dev->bdev,
2814 ca->block_size, may_format,
2815 dm_cache_policy_get_hint_size(cache->policy));
2817 *error = "Error creating metadata object";
2822 set_cache_mode(cache, CM_WRITE);
2823 if (get_cache_mode(cache) != CM_WRITE) {
2824 *error = "Unable to get write access to metadata, please check/repair metadata.";
2829 if (passthrough_mode(&cache->features)) {
2832 r = dm_cache_metadata_all_clean(cache->cmd, &all_clean);
2834 *error = "dm_cache_metadata_all_clean() failed";
2839 *error = "Cannot enter passthrough mode unless all blocks are clean";
2845 spin_lock_init(&cache->lock);
2846 INIT_LIST_HEAD(&cache->deferred_cells);
2847 bio_list_init(&cache->deferred_bios);
2848 bio_list_init(&cache->deferred_flush_bios);
2849 bio_list_init(&cache->deferred_writethrough_bios);
2850 INIT_LIST_HEAD(&cache->quiesced_migrations);
2851 INIT_LIST_HEAD(&cache->completed_migrations);
2852 INIT_LIST_HEAD(&cache->need_commit_migrations);
2853 atomic_set(&cache->nr_allocated_migrations, 0);
2854 atomic_set(&cache->nr_io_migrations, 0);
2855 init_waitqueue_head(&cache->migration_wait);
2857 init_waitqueue_head(&cache->quiescing_wait);
2858 atomic_set(&cache->quiescing, 0);
2859 atomic_set(&cache->quiescing_ack, 0);
2862 atomic_set(&cache->nr_dirty, 0);
2863 cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size));
2864 if (!cache->dirty_bitset) {
2865 *error = "could not allocate dirty bitset";
2868 clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
2870 cache->discard_block_size =
2871 calculate_discard_block_size(cache->sectors_per_block,
2872 cache->origin_sectors);
2873 cache->discard_nr_blocks = to_dblock(dm_sector_div_up(cache->origin_sectors,
2874 cache->discard_block_size));
2875 cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks));
2876 if (!cache->discard_bitset) {
2877 *error = "could not allocate discard bitset";
2880 clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));
2882 cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2883 if (IS_ERR(cache->copier)) {
2884 *error = "could not create kcopyd client";
2885 r = PTR_ERR(cache->copier);
2889 cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2891 *error = "could not create workqueue for metadata object";
2894 INIT_WORK(&cache->worker, do_worker);
2895 INIT_DELAYED_WORK(&cache->waker, do_waker);
2896 cache->last_commit_jiffies = jiffies;
2898 cache->prison = dm_bio_prison_create();
2899 if (!cache->prison) {
2900 *error = "could not create bio prison";
2904 cache->all_io_ds = dm_deferred_set_create();
2905 if (!cache->all_io_ds) {
2906 *error = "could not create all_io deferred set";
2910 cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE,
2912 if (!cache->migration_pool) {
2913 *error = "Error creating cache's migration mempool";
2917 cache->need_tick_bio = true;
2918 cache->sized = false;
2919 cache->invalidate = false;
2920 cache->commit_requested = false;
2921 cache->loaded_mappings = false;
2922 cache->loaded_discards = false;
2926 atomic_set(&cache->stats.demotion, 0);
2927 atomic_set(&cache->stats.promotion, 0);
2928 atomic_set(&cache->stats.copies_avoided, 0);
2929 atomic_set(&cache->stats.cache_cell_clash, 0);
2930 atomic_set(&cache->stats.commit_count, 0);
2931 atomic_set(&cache->stats.discard_count, 0);
2933 spin_lock_init(&cache->invalidation_lock);
2934 INIT_LIST_HEAD(&cache->invalidation_requests);
2936 iot_init(&cache->origin_tracker);
2946 static int copy_ctr_args(struct cache *cache, int argc, const char **argv)
2951 copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL);
2954 for (i = 0; i < argc; i++) {
2955 copy[i] = kstrdup(argv[i], GFP_KERNEL);
2964 cache->nr_ctr_args = argc;
2965 cache->ctr_args = copy;
2970 static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv)
2973 struct cache_args *ca;
2974 struct cache *cache = NULL;
2976 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2978 ti->error = "Error allocating memory for cache";
2983 r = parse_cache_args(ca, argc, argv, &ti->error);
2987 r = cache_create(ca, &cache);
2991 r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3);
2997 ti->private = cache;
3000 destroy_cache_args(ca);
3004 /*----------------------------------------------------------------*/
3006 static int cache_map(struct dm_target *ti, struct bio *bio)
3008 struct cache *cache = ti->private;
3011 struct dm_bio_prison_cell *cell = NULL;
3012 dm_oblock_t block = get_bio_block(cache, bio);
3013 size_t pb_data_size = get_per_bio_data_size(cache);
3014 bool can_migrate = false;
3015 bool fast_promotion;
3016 struct policy_result lookup_result;
3017 struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size);
3018 struct old_oblock_lock ool;
3020 ool.locker.fn = null_locker;
3022 if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) {
3024 * This can only occur if the io goes to a partial block at
3025 * the end of the origin device. We don't cache these.
3026 * Just remap to the origin and carry on.
3028 remap_to_origin(cache, bio);
3029 accounted_begin(cache, bio);
3030 return DM_MAPIO_REMAPPED;
3033 if (discard_or_flush(bio)) {
3034 defer_bio(cache, bio);
3035 return DM_MAPIO_SUBMITTED;
3039 * Check to see if that block is currently migrating.
3041 cell = alloc_prison_cell(cache);
3043 defer_bio(cache, bio);
3044 return DM_MAPIO_SUBMITTED;
3047 r = bio_detain(cache, block, bio, cell,
3048 (cell_free_fn) free_prison_cell,
3052 defer_bio(cache, bio);
3054 return DM_MAPIO_SUBMITTED;
3057 fast_promotion = is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio);
3059 r = policy_map(cache->policy, block, false, can_migrate, fast_promotion,
3060 bio, &ool.locker, &lookup_result);
3061 if (r == -EWOULDBLOCK) {
3062 cell_defer(cache, cell, true);
3063 return DM_MAPIO_SUBMITTED;
3066 DMERR_LIMIT("%s: Unexpected return from cache replacement policy: %d",
3067 cache_device_name(cache), r);
3068 cell_defer(cache, cell, false);
3070 return DM_MAPIO_SUBMITTED;
3073 r = DM_MAPIO_REMAPPED;
3074 switch (lookup_result.op) {
3076 if (passthrough_mode(&cache->features)) {
3077 if (bio_data_dir(bio) == WRITE) {
3079 * We need to invalidate this block, so
3080 * defer for the worker thread.
3082 cell_defer(cache, cell, true);
3083 r = DM_MAPIO_SUBMITTED;
3086 inc_miss_counter(cache, bio);
3087 remap_to_origin_clear_discard(cache, bio, block);
3088 accounted_begin(cache, bio);
3089 inc_ds(cache, bio, cell);
3090 // FIXME: we want to remap hits or misses straight
3091 // away rather than passing over to the worker.
3092 cell_defer(cache, cell, false);
3096 inc_hit_counter(cache, bio);
3097 if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) &&
3098 !is_dirty(cache, lookup_result.cblock)) {
3099 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
3100 accounted_begin(cache, bio);
3101 inc_ds(cache, bio, cell);
3102 cell_defer(cache, cell, false);
3105 remap_cell_to_cache_dirty(cache, cell, block, lookup_result.cblock, false);
3110 inc_miss_counter(cache, bio);
3111 if (pb->req_nr != 0) {
3113 * This is a duplicate writethrough io that is no
3114 * longer needed because the block has been demoted.
3117 // FIXME: remap everything as a miss
3118 cell_defer(cache, cell, false);
3119 r = DM_MAPIO_SUBMITTED;
3122 remap_cell_to_origin_clear_discard(cache, cell, block, false);
3126 DMERR_LIMIT("%s: %s: erroring bio: unknown policy op: %u",
3127 cache_device_name(cache), __func__,
3128 (unsigned) lookup_result.op);
3129 cell_defer(cache, cell, false);
3131 r = DM_MAPIO_SUBMITTED;
3137 static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
3139 struct cache *cache = ti->private;
3140 unsigned long flags;
3141 size_t pb_data_size = get_per_bio_data_size(cache);
3142 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
3145 policy_tick(cache->policy, false);
3147 spin_lock_irqsave(&cache->lock, flags);
3148 cache->need_tick_bio = true;
3149 spin_unlock_irqrestore(&cache->lock, flags);
3152 check_for_quiesced_migrations(cache, pb);
3153 accounted_complete(cache, bio);
3158 static int write_dirty_bitset(struct cache *cache)
3162 if (get_cache_mode(cache) >= CM_READ_ONLY)
3165 for (i = 0; i < from_cblock(cache->cache_size); i++) {
3166 r = dm_cache_set_dirty(cache->cmd, to_cblock(i),
3167 is_dirty(cache, to_cblock(i)));
3169 metadata_operation_failed(cache, "dm_cache_set_dirty", r);
3177 static int write_discard_bitset(struct cache *cache)
3181 if (get_cache_mode(cache) >= CM_READ_ONLY)
3184 r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size,
3185 cache->discard_nr_blocks);
3187 DMERR("%s: could not resize on-disk discard bitset", cache_device_name(cache));
3188 metadata_operation_failed(cache, "dm_cache_discard_bitset_resize", r);
3192 for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) {
3193 r = dm_cache_set_discard(cache->cmd, to_dblock(i),
3194 is_discarded(cache, to_dblock(i)));
3196 metadata_operation_failed(cache, "dm_cache_set_discard", r);
3204 static int write_hints(struct cache *cache)
3208 if (get_cache_mode(cache) >= CM_READ_ONLY)
3211 r = dm_cache_write_hints(cache->cmd, cache->policy);
3213 metadata_operation_failed(cache, "dm_cache_write_hints", r);
3221 * returns true on success
3223 static bool sync_metadata(struct cache *cache)
3227 r1 = write_dirty_bitset(cache);
3229 DMERR("%s: could not write dirty bitset", cache_device_name(cache));
3231 r2 = write_discard_bitset(cache);
3233 DMERR("%s: could not write discard bitset", cache_device_name(cache));
3237 r3 = write_hints(cache);
3239 DMERR("%s: could not write hints", cache_device_name(cache));
3242 * If writing the above metadata failed, we still commit, but don't
3243 * set the clean shutdown flag. This will effectively force every
3244 * dirty bit to be set on reload.
3246 r4 = commit(cache, !r1 && !r2 && !r3);
3248 DMERR("%s: could not write cache metadata", cache_device_name(cache));
3250 return !r1 && !r2 && !r3 && !r4;
3253 static void cache_postsuspend(struct dm_target *ti)
3255 struct cache *cache = ti->private;
3257 start_quiescing(cache);
3258 wait_for_migrations(cache);
3260 requeue_deferred_bios(cache);
3261 requeue_deferred_cells(cache);
3262 stop_quiescing(cache);
3264 if (get_cache_mode(cache) == CM_WRITE)
3265 (void) sync_metadata(cache);
3268 static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
3269 bool dirty, uint32_t hint, bool hint_valid)
3272 struct cache *cache = context;
3274 r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid);
3279 set_dirty(cache, oblock, cblock);
3281 clear_dirty(cache, oblock, cblock);
3287 * The discard block size in the on disk metadata is not
3288 * neccessarily the same as we're currently using. So we have to
3289 * be careful to only set the discarded attribute if we know it
3290 * covers a complete block of the new size.
3292 struct discard_load_info {
3293 struct cache *cache;
3296 * These blocks are sized using the on disk dblock size, rather
3297 * than the current one.
3299 dm_block_t block_size;
3300 dm_block_t discard_begin, discard_end;
3303 static void discard_load_info_init(struct cache *cache,
3304 struct discard_load_info *li)
3307 li->discard_begin = li->discard_end = 0;
3310 static void set_discard_range(struct discard_load_info *li)
3314 if (li->discard_begin == li->discard_end)
3318 * Convert to sectors.
3320 b = li->discard_begin * li->block_size;
3321 e = li->discard_end * li->block_size;
3324 * Then convert back to the current dblock size.
3326 b = dm_sector_div_up(b, li->cache->discard_block_size);
3327 sector_div(e, li->cache->discard_block_size);
3330 * The origin may have shrunk, so we need to check we're still in
3333 if (e > from_dblock(li->cache->discard_nr_blocks))
3334 e = from_dblock(li->cache->discard_nr_blocks);
3337 set_discard(li->cache, to_dblock(b));
3340 static int load_discard(void *context, sector_t discard_block_size,
3341 dm_dblock_t dblock, bool discard)
3343 struct discard_load_info *li = context;
3345 li->block_size = discard_block_size;
3348 if (from_dblock(dblock) == li->discard_end)
3350 * We're already in a discard range, just extend it.
3352 li->discard_end = li->discard_end + 1ULL;
3356 * Emit the old range and start a new one.
3358 set_discard_range(li);
3359 li->discard_begin = from_dblock(dblock);
3360 li->discard_end = li->discard_begin + 1ULL;
3363 set_discard_range(li);
3364 li->discard_begin = li->discard_end = 0;
3370 static dm_cblock_t get_cache_dev_size(struct cache *cache)
3372 sector_t size = get_dev_size(cache->cache_dev);
3373 (void) sector_div(size, cache->sectors_per_block);
3374 return to_cblock(size);
3377 static bool can_resize(struct cache *cache, dm_cblock_t new_size)
3379 if (from_cblock(new_size) > from_cblock(cache->cache_size))
3383 * We can't drop a dirty block when shrinking the cache.
3385 while (from_cblock(new_size) < from_cblock(cache->cache_size)) {
3386 new_size = to_cblock(from_cblock(new_size) + 1);
3387 if (is_dirty(cache, new_size)) {
3388 DMERR("%s: unable to shrink cache; cache block %llu is dirty",
3389 cache_device_name(cache),
3390 (unsigned long long) from_cblock(new_size));
3398 static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size)
3402 r = dm_cache_resize(cache->cmd, new_size);
3404 DMERR("%s: could not resize cache metadata", cache_device_name(cache));
3405 metadata_operation_failed(cache, "dm_cache_resize", r);
3409 set_cache_size(cache, new_size);
3414 static int cache_preresume(struct dm_target *ti)
3417 struct cache *cache = ti->private;
3418 dm_cblock_t csize = get_cache_dev_size(cache);
3421 * Check to see if the cache has resized.
3423 if (!cache->sized) {
3424 r = resize_cache_dev(cache, csize);
3428 cache->sized = true;
3430 } else if (csize != cache->cache_size) {
3431 if (!can_resize(cache, csize))
3434 r = resize_cache_dev(cache, csize);
3439 if (!cache->loaded_mappings) {
3440 r = dm_cache_load_mappings(cache->cmd, cache->policy,
3441 load_mapping, cache);
3443 DMERR("%s: could not load cache mappings", cache_device_name(cache));
3444 metadata_operation_failed(cache, "dm_cache_load_mappings", r);
3448 cache->loaded_mappings = true;
3451 if (!cache->loaded_discards) {
3452 struct discard_load_info li;
3455 * The discard bitset could have been resized, or the
3456 * discard block size changed. To be safe we start by
3457 * setting every dblock to not discarded.
3459 clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));
3461 discard_load_info_init(cache, &li);
3462 r = dm_cache_load_discards(cache->cmd, load_discard, &li);
3464 DMERR("%s: could not load origin discards", cache_device_name(cache));
3465 metadata_operation_failed(cache, "dm_cache_load_discards", r);
3468 set_discard_range(&li);
3470 cache->loaded_discards = true;
3476 static void cache_resume(struct dm_target *ti)
3478 struct cache *cache = ti->private;
3480 cache->need_tick_bio = true;
3481 do_waker(&cache->waker.work);
3487 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
3488 * <cache block size> <#used cache blocks>/<#total cache blocks>
3489 * <#read hits> <#read misses> <#write hits> <#write misses>
3490 * <#demotions> <#promotions> <#dirty>
3491 * <#features> <features>*
3492 * <#core args> <core args>
3493 * <policy name> <#policy args> <policy args>* <cache metadata mode> <needs_check>
3495 static void cache_status(struct dm_target *ti, status_type_t type,
3496 unsigned status_flags, char *result, unsigned maxlen)
3501 dm_block_t nr_free_blocks_metadata = 0;
3502 dm_block_t nr_blocks_metadata = 0;
3503 char buf[BDEVNAME_SIZE];
3504 struct cache *cache = ti->private;
3505 dm_cblock_t residency;
3508 case STATUSTYPE_INFO:
3509 if (get_cache_mode(cache) == CM_FAIL) {
3514 /* Commit to ensure statistics aren't out-of-date */
3515 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3516 (void) commit(cache, false);
3518 r = dm_cache_get_free_metadata_block_count(cache->cmd, &nr_free_blocks_metadata);
3520 DMERR("%s: dm_cache_get_free_metadata_block_count returned %d",
3521 cache_device_name(cache), r);
3525 r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata);
3527 DMERR("%s: dm_cache_get_metadata_dev_size returned %d",
3528 cache_device_name(cache), r);
3532 residency = policy_residency(cache->policy);
3534 DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %lu ",
3535 (unsigned)DM_CACHE_METADATA_BLOCK_SIZE,
3536 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3537 (unsigned long long)nr_blocks_metadata,
3538 cache->sectors_per_block,
3539 (unsigned long long) from_cblock(residency),
3540 (unsigned long long) from_cblock(cache->cache_size),
3541 (unsigned) atomic_read(&cache->stats.read_hit),
3542 (unsigned) atomic_read(&cache->stats.read_miss),
3543 (unsigned) atomic_read(&cache->stats.write_hit),
3544 (unsigned) atomic_read(&cache->stats.write_miss),
3545 (unsigned) atomic_read(&cache->stats.demotion),
3546 (unsigned) atomic_read(&cache->stats.promotion),
3547 (unsigned long) atomic_read(&cache->nr_dirty));
3549 if (writethrough_mode(&cache->features))
3550 DMEMIT("1 writethrough ");
3552 else if (passthrough_mode(&cache->features))
3553 DMEMIT("1 passthrough ");
3555 else if (writeback_mode(&cache->features))
3556 DMEMIT("1 writeback ");
3559 DMERR("%s: internal error: unknown io mode: %d",
3560 cache_device_name(cache), (int) cache->features.io_mode);
3564 DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
3566 DMEMIT("%s ", dm_cache_policy_get_name(cache->policy));
3568 r = policy_emit_config_values(cache->policy, result, maxlen, &sz);
3570 DMERR("%s: policy_emit_config_values returned %d",
3571 cache_device_name(cache), r);
3574 if (get_cache_mode(cache) == CM_READ_ONLY)
3579 if (dm_cache_metadata_needs_check(cache->cmd))
3580 DMEMIT("needs_check ");
3586 case STATUSTYPE_TABLE:
3587 format_dev_t(buf, cache->metadata_dev->bdev->bd_dev);
3589 format_dev_t(buf, cache->cache_dev->bdev->bd_dev);
3591 format_dev_t(buf, cache->origin_dev->bdev->bd_dev);
3594 for (i = 0; i < cache->nr_ctr_args - 1; i++)
3595 DMEMIT(" %s", cache->ctr_args[i]);
3596 if (cache->nr_ctr_args)
3597 DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]);
3607 * A cache block range can take two forms:
3609 * i) A single cblock, eg. '3456'
3610 * ii) A begin and end cblock with dots between, eg. 123-234
3612 static int parse_cblock_range(struct cache *cache, const char *str,
3613 struct cblock_range *result)
3620 * Try and parse form (ii) first.
3622 r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy);
3627 result->begin = to_cblock(b);
3628 result->end = to_cblock(e);
3633 * That didn't work, try form (i).
3635 r = sscanf(str, "%llu%c", &b, &dummy);
3640 result->begin = to_cblock(b);
3641 result->end = to_cblock(from_cblock(result->begin) + 1u);
3645 DMERR("%s: invalid cblock range '%s'", cache_device_name(cache), str);
3649 static int validate_cblock_range(struct cache *cache, struct cblock_range *range)
3651 uint64_t b = from_cblock(range->begin);
3652 uint64_t e = from_cblock(range->end);
3653 uint64_t n = from_cblock(cache->cache_size);
3656 DMERR("%s: begin cblock out of range: %llu >= %llu",
3657 cache_device_name(cache), b, n);
3662 DMERR("%s: end cblock out of range: %llu > %llu",
3663 cache_device_name(cache), e, n);
3668 DMERR("%s: invalid cblock range: %llu >= %llu",
3669 cache_device_name(cache), b, e);
3676 static int request_invalidation(struct cache *cache, struct cblock_range *range)
3678 struct invalidation_request req;
3680 INIT_LIST_HEAD(&req.list);
3681 req.cblocks = range;
3682 atomic_set(&req.complete, 0);
3684 init_waitqueue_head(&req.result_wait);
3686 spin_lock(&cache->invalidation_lock);
3687 list_add(&req.list, &cache->invalidation_requests);
3688 spin_unlock(&cache->invalidation_lock);
3691 wait_event(req.result_wait, atomic_read(&req.complete));
3695 static int process_invalidate_cblocks_message(struct cache *cache, unsigned count,
3696 const char **cblock_ranges)
3700 struct cblock_range range;
3702 if (!passthrough_mode(&cache->features)) {
3703 DMERR("%s: cache has to be in passthrough mode for invalidation",
3704 cache_device_name(cache));
3708 for (i = 0; i < count; i++) {
3709 r = parse_cblock_range(cache, cblock_ranges[i], &range);
3713 r = validate_cblock_range(cache, &range);
3718 * Pass begin and end origin blocks to the worker and wake it.
3720 r = request_invalidation(cache, &range);
3732 * "invalidate_cblocks [(<begin>)|(<begin>-<end>)]*
3734 * The key migration_threshold is supported by the cache target core.
3736 static int cache_message(struct dm_target *ti, unsigned argc, char **argv)
3738 struct cache *cache = ti->private;
3743 if (get_cache_mode(cache) >= CM_READ_ONLY) {
3744 DMERR("%s: unable to service cache target messages in READ_ONLY or FAIL mode",
3745 cache_device_name(cache));
3749 if (!strcasecmp(argv[0], "invalidate_cblocks"))
3750 return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1);
3755 return set_config_value(cache, argv[0], argv[1]);
3758 static int cache_iterate_devices(struct dm_target *ti,
3759 iterate_devices_callout_fn fn, void *data)
3762 struct cache *cache = ti->private;
3764 r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data);
3766 r = fn(ti, cache->origin_dev, 0, ti->len, data);
3772 * We assume I/O is going to the origin (which is the volume
3773 * more likely to have restrictions e.g. by being striped).
3774 * (Looking up the exact location of the data would be expensive
3775 * and could always be out of date by the time the bio is submitted.)
3777 static int cache_bvec_merge(struct dm_target *ti,
3778 struct bvec_merge_data *bvm,
3779 struct bio_vec *biovec, int max_size)
3781 struct cache *cache = ti->private;
3782 struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev);
3784 if (!q->merge_bvec_fn)
3787 bvm->bi_bdev = cache->origin_dev->bdev;
3788 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3791 static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
3794 * FIXME: these limits may be incompatible with the cache device
3796 limits->max_discard_sectors = min_t(sector_t, cache->discard_block_size * 1024,
3797 cache->origin_sectors);
3798 limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
3801 static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
3803 struct cache *cache = ti->private;
3804 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
3807 * If the system-determined stacked limits are compatible with the
3808 * cache's blocksize (io_opt is a factor) do not override them.
3810 if (io_opt_sectors < cache->sectors_per_block ||
3811 do_div(io_opt_sectors, cache->sectors_per_block)) {
3812 blk_limits_io_min(limits, cache->sectors_per_block << SECTOR_SHIFT);
3813 blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
3815 set_discard_limits(cache, limits);
3818 /*----------------------------------------------------------------*/
3820 static struct target_type cache_target = {
3822 .version = {1, 8, 0},
3823 .module = THIS_MODULE,
3827 .end_io = cache_end_io,
3828 .postsuspend = cache_postsuspend,
3829 .preresume = cache_preresume,
3830 .resume = cache_resume,
3831 .status = cache_status,
3832 .message = cache_message,
3833 .iterate_devices = cache_iterate_devices,
3834 .merge = cache_bvec_merge,
3835 .io_hints = cache_io_hints,
3838 static int __init dm_cache_init(void)
3842 r = dm_register_target(&cache_target);
3844 DMERR("cache target registration failed: %d", r);
3848 migration_cache = KMEM_CACHE(dm_cache_migration, 0);
3849 if (!migration_cache) {
3850 dm_unregister_target(&cache_target);
3857 static void __exit dm_cache_exit(void)
3859 dm_unregister_target(&cache_target);
3860 kmem_cache_destroy(migration_cache);
3863 module_init(dm_cache_init);
3864 module_exit(dm_cache_exit);
3866 MODULE_DESCRIPTION(DM_NAME " cache target");
3867 MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
3868 MODULE_LICENSE("GPL");