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);
430 static int prealloc_data_structs(struct cache *cache, struct prealloc *p)
433 p->mg = alloc_migration(cache);
439 p->cell1 = alloc_prison_cell(cache);
445 p->cell2 = alloc_prison_cell(cache);
453 static void prealloc_free_structs(struct cache *cache, struct prealloc *p)
456 free_prison_cell(cache, p->cell2);
459 free_prison_cell(cache, p->cell1);
462 free_migration(p->mg);
465 static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p)
467 struct dm_cache_migration *mg = p->mg;
476 * You must have a cell within the prealloc struct to return. If not this
477 * function will BUG() rather than returning NULL.
479 static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p)
481 struct dm_bio_prison_cell *r = NULL;
487 } else if (p->cell2) {
497 * You can't have more than two cells in a prealloc struct. BUG() will be
498 * called if you try and overfill.
500 static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell)
512 /*----------------------------------------------------------------*/
514 static void build_key(dm_oblock_t begin, dm_oblock_t end, struct dm_cell_key *key)
518 key->block_begin = from_oblock(begin);
519 key->block_end = from_oblock(end);
523 * The caller hands in a preallocated cell, and a free function for it.
524 * The cell will be freed if there's an error, or if it wasn't used because
525 * a cell with that key already exists.
527 typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell);
529 static int bio_detain_range(struct cache *cache, dm_oblock_t oblock_begin, dm_oblock_t oblock_end,
530 struct bio *bio, struct dm_bio_prison_cell *cell_prealloc,
531 cell_free_fn free_fn, void *free_context,
532 struct dm_bio_prison_cell **cell_result)
535 struct dm_cell_key key;
537 build_key(oblock_begin, oblock_end, &key);
538 r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result);
540 free_fn(free_context, cell_prealloc);
545 static int bio_detain(struct cache *cache, dm_oblock_t oblock,
546 struct bio *bio, struct dm_bio_prison_cell *cell_prealloc,
547 cell_free_fn free_fn, void *free_context,
548 struct dm_bio_prison_cell **cell_result)
550 dm_oblock_t end = to_oblock(from_oblock(oblock) + 1ULL);
551 return bio_detain_range(cache, oblock, end, bio,
552 cell_prealloc, free_fn, free_context, cell_result);
555 static int get_cell(struct cache *cache,
557 struct prealloc *structs,
558 struct dm_bio_prison_cell **cell_result)
561 struct dm_cell_key key;
562 struct dm_bio_prison_cell *cell_prealloc;
564 cell_prealloc = prealloc_get_cell(structs);
566 build_key(oblock, to_oblock(from_oblock(oblock) + 1ULL), &key);
567 r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result);
569 prealloc_put_cell(structs, cell_prealloc);
574 /*----------------------------------------------------------------*/
576 static bool is_dirty(struct cache *cache, dm_cblock_t b)
578 return test_bit(from_cblock(b), cache->dirty_bitset);
581 static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
583 if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) {
584 atomic_inc(&cache->nr_dirty);
585 policy_set_dirty(cache->policy, oblock);
589 static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock)
591 if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) {
592 policy_clear_dirty(cache->policy, oblock);
593 if (atomic_dec_return(&cache->nr_dirty) == 0)
594 dm_table_event(cache->ti->table);
598 /*----------------------------------------------------------------*/
600 static bool block_size_is_power_of_two(struct cache *cache)
602 return cache->sectors_per_block_shift >= 0;
605 /* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */
606 #if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6
609 static dm_block_t block_div(dm_block_t b, uint32_t n)
616 static dm_block_t oblocks_per_dblock(struct cache *cache)
618 dm_block_t oblocks = cache->discard_block_size;
620 if (block_size_is_power_of_two(cache))
621 oblocks >>= cache->sectors_per_block_shift;
623 oblocks = block_div(oblocks, cache->sectors_per_block);
628 static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock)
630 return to_dblock(block_div(from_oblock(oblock),
631 oblocks_per_dblock(cache)));
634 static dm_oblock_t dblock_to_oblock(struct cache *cache, dm_dblock_t dblock)
636 return to_oblock(from_dblock(dblock) * oblocks_per_dblock(cache));
639 static void set_discard(struct cache *cache, dm_dblock_t b)
643 BUG_ON(from_dblock(b) >= from_dblock(cache->discard_nr_blocks));
644 atomic_inc(&cache->stats.discard_count);
646 spin_lock_irqsave(&cache->lock, flags);
647 set_bit(from_dblock(b), cache->discard_bitset);
648 spin_unlock_irqrestore(&cache->lock, flags);
651 static void clear_discard(struct cache *cache, dm_dblock_t b)
655 spin_lock_irqsave(&cache->lock, flags);
656 clear_bit(from_dblock(b), cache->discard_bitset);
657 spin_unlock_irqrestore(&cache->lock, flags);
660 static bool is_discarded(struct cache *cache, dm_dblock_t b)
665 spin_lock_irqsave(&cache->lock, flags);
666 r = test_bit(from_dblock(b), cache->discard_bitset);
667 spin_unlock_irqrestore(&cache->lock, flags);
672 static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b)
677 spin_lock_irqsave(&cache->lock, flags);
678 r = test_bit(from_dblock(oblock_to_dblock(cache, b)),
679 cache->discard_bitset);
680 spin_unlock_irqrestore(&cache->lock, flags);
685 /*----------------------------------------------------------------*/
687 static void load_stats(struct cache *cache)
689 struct dm_cache_statistics stats;
691 dm_cache_metadata_get_stats(cache->cmd, &stats);
692 atomic_set(&cache->stats.read_hit, stats.read_hits);
693 atomic_set(&cache->stats.read_miss, stats.read_misses);
694 atomic_set(&cache->stats.write_hit, stats.write_hits);
695 atomic_set(&cache->stats.write_miss, stats.write_misses);
698 static void save_stats(struct cache *cache)
700 struct dm_cache_statistics stats;
702 if (get_cache_mode(cache) >= CM_READ_ONLY)
705 stats.read_hits = atomic_read(&cache->stats.read_hit);
706 stats.read_misses = atomic_read(&cache->stats.read_miss);
707 stats.write_hits = atomic_read(&cache->stats.write_hit);
708 stats.write_misses = atomic_read(&cache->stats.write_miss);
710 dm_cache_metadata_set_stats(cache->cmd, &stats);
713 /*----------------------------------------------------------------
715 *--------------------------------------------------------------*/
718 * If using writeback, leave out struct per_bio_data's writethrough fields.
720 #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache))
721 #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data))
723 static bool writethrough_mode(struct cache_features *f)
725 return f->io_mode == CM_IO_WRITETHROUGH;
728 static bool writeback_mode(struct cache_features *f)
730 return f->io_mode == CM_IO_WRITEBACK;
733 static bool passthrough_mode(struct cache_features *f)
735 return f->io_mode == CM_IO_PASSTHROUGH;
738 static size_t get_per_bio_data_size(struct cache *cache)
740 return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB;
743 static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size)
745 struct per_bio_data *pb = dm_per_bio_data(bio, data_size);
750 static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size)
752 struct per_bio_data *pb = get_per_bio_data(bio, data_size);
755 pb->req_nr = dm_bio_get_target_bio_nr(bio);
756 pb->all_io_entry = NULL;
762 /*----------------------------------------------------------------
764 *--------------------------------------------------------------*/
765 static void remap_to_origin(struct cache *cache, struct bio *bio)
767 bio->bi_bdev = cache->origin_dev->bdev;
770 static void remap_to_cache(struct cache *cache, struct bio *bio,
773 sector_t bi_sector = bio->bi_iter.bi_sector;
774 sector_t block = from_cblock(cblock);
776 bio->bi_bdev = cache->cache_dev->bdev;
777 if (!block_size_is_power_of_two(cache))
778 bio->bi_iter.bi_sector =
779 (block * cache->sectors_per_block) +
780 sector_div(bi_sector, cache->sectors_per_block);
782 bio->bi_iter.bi_sector =
783 (block << cache->sectors_per_block_shift) |
784 (bi_sector & (cache->sectors_per_block - 1));
787 static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)
790 size_t pb_data_size = get_per_bio_data_size(cache);
791 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
793 spin_lock_irqsave(&cache->lock, flags);
794 if (cache->need_tick_bio &&
795 !(bio->bi_rw & (REQ_FUA | REQ_FLUSH | REQ_DISCARD))) {
797 cache->need_tick_bio = false;
799 spin_unlock_irqrestore(&cache->lock, flags);
802 static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio,
805 check_if_tick_bio_needed(cache, bio);
806 remap_to_origin(cache, bio);
807 if (bio_data_dir(bio) == WRITE)
808 clear_discard(cache, oblock_to_dblock(cache, oblock));
811 static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
812 dm_oblock_t oblock, dm_cblock_t cblock)
814 check_if_tick_bio_needed(cache, bio);
815 remap_to_cache(cache, bio, cblock);
816 if (bio_data_dir(bio) == WRITE) {
817 set_dirty(cache, oblock, cblock);
818 clear_discard(cache, oblock_to_dblock(cache, oblock));
822 static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio)
824 sector_t block_nr = bio->bi_iter.bi_sector;
826 if (!block_size_is_power_of_two(cache))
827 (void) sector_div(block_nr, cache->sectors_per_block);
829 block_nr >>= cache->sectors_per_block_shift;
831 return to_oblock(block_nr);
834 static int bio_triggers_commit(struct cache *cache, struct bio *bio)
836 return bio->bi_rw & (REQ_FLUSH | REQ_FUA);
840 * You must increment the deferred set whilst the prison cell is held. To
841 * encourage this, we ask for 'cell' to be passed in.
843 static void inc_ds(struct cache *cache, struct bio *bio,
844 struct dm_bio_prison_cell *cell)
846 size_t pb_data_size = get_per_bio_data_size(cache);
847 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
850 BUG_ON(pb->all_io_entry);
852 pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
855 static bool accountable_bio(struct cache *cache, struct bio *bio)
857 return ((bio->bi_bdev == cache->origin_dev->bdev) &&
858 !(bio->bi_rw & REQ_DISCARD));
861 static void accounted_begin(struct cache *cache, struct bio *bio)
863 size_t pb_data_size = get_per_bio_data_size(cache);
864 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
866 if (accountable_bio(cache, bio)) {
867 pb->len = bio_sectors(bio);
868 iot_io_begin(&cache->origin_tracker, pb->len);
872 static void accounted_complete(struct cache *cache, struct bio *bio)
874 size_t pb_data_size = get_per_bio_data_size(cache);
875 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
877 iot_io_end(&cache->origin_tracker, pb->len);
880 static void accounted_request(struct cache *cache, struct bio *bio)
882 accounted_begin(cache, bio);
883 generic_make_request(bio);
886 static void issue(struct cache *cache, struct bio *bio)
890 if (!bio_triggers_commit(cache, bio)) {
891 accounted_request(cache, bio);
896 * Batch together any bios that trigger commits and then issue a
897 * single commit for them in do_worker().
899 spin_lock_irqsave(&cache->lock, flags);
900 cache->commit_requested = true;
901 bio_list_add(&cache->deferred_flush_bios, bio);
902 spin_unlock_irqrestore(&cache->lock, flags);
905 static void inc_and_issue(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell *cell)
907 inc_ds(cache, bio, cell);
911 static void defer_writethrough_bio(struct cache *cache, struct bio *bio)
915 spin_lock_irqsave(&cache->lock, flags);
916 bio_list_add(&cache->deferred_writethrough_bios, bio);
917 spin_unlock_irqrestore(&cache->lock, flags);
922 static void writethrough_endio(struct bio *bio, int err)
924 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
926 dm_unhook_bio(&pb->hook_info, bio);
933 dm_bio_restore(&pb->bio_details, bio);
934 remap_to_cache(pb->cache, bio, pb->cblock);
937 * We can't issue this bio directly, since we're in interrupt
938 * context. So it gets put on a bio list for processing by the
941 defer_writethrough_bio(pb->cache, bio);
945 * When running in writethrough mode we need to send writes to clean blocks
946 * to both the cache and origin devices. In future we'd like to clone the
947 * bio and send them in parallel, but for now we're doing them in
948 * series as this is easier.
950 static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio,
951 dm_oblock_t oblock, dm_cblock_t cblock)
953 struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);
957 dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL);
958 dm_bio_record(&pb->bio_details, bio);
960 remap_to_origin_clear_discard(pb->cache, bio, oblock);
963 /*----------------------------------------------------------------
965 *--------------------------------------------------------------*/
966 static enum cache_metadata_mode get_cache_mode(struct cache *cache)
968 return cache->features.mode;
971 static const char *cache_device_name(struct cache *cache)
973 return dm_device_name(dm_table_get_md(cache->ti->table));
976 static void notify_mode_switch(struct cache *cache, enum cache_metadata_mode mode)
978 const char *descs[] = {
984 dm_table_event(cache->ti->table);
985 DMINFO("%s: switching cache to %s mode",
986 cache_device_name(cache), descs[(int)mode]);
989 static void set_cache_mode(struct cache *cache, enum cache_metadata_mode new_mode)
991 bool needs_check = dm_cache_metadata_needs_check(cache->cmd);
992 enum cache_metadata_mode old_mode = get_cache_mode(cache);
994 if (new_mode == CM_WRITE && needs_check) {
995 DMERR("%s: unable to switch cache to write mode until repaired.",
996 cache_device_name(cache));
997 if (old_mode != new_mode)
1000 new_mode = CM_READ_ONLY;
1003 /* Never move out of fail mode */
1004 if (old_mode == CM_FAIL)
1010 dm_cache_metadata_set_read_only(cache->cmd);
1014 dm_cache_metadata_set_read_write(cache->cmd);
1018 cache->features.mode = new_mode;
1020 if (new_mode != old_mode)
1021 notify_mode_switch(cache, new_mode);
1024 static void abort_transaction(struct cache *cache)
1026 const char *dev_name = cache_device_name(cache);
1028 if (get_cache_mode(cache) >= CM_READ_ONLY)
1031 if (dm_cache_metadata_set_needs_check(cache->cmd)) {
1032 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
1033 set_cache_mode(cache, CM_FAIL);
1036 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
1037 if (dm_cache_metadata_abort(cache->cmd)) {
1038 DMERR("%s: failed to abort metadata transaction", dev_name);
1039 set_cache_mode(cache, CM_FAIL);
1043 static void metadata_operation_failed(struct cache *cache, const char *op, int r)
1045 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
1046 cache_device_name(cache), op, r);
1047 abort_transaction(cache);
1048 set_cache_mode(cache, CM_READ_ONLY);
1051 /*----------------------------------------------------------------
1052 * Migration processing
1054 * Migration covers moving data from the origin device to the cache, or
1056 *--------------------------------------------------------------*/
1057 static void inc_io_migrations(struct cache *cache)
1059 atomic_inc(&cache->nr_io_migrations);
1062 static void dec_io_migrations(struct cache *cache)
1064 atomic_dec(&cache->nr_io_migrations);
1067 static void __cell_release(struct cache *cache, struct dm_bio_prison_cell *cell,
1068 bool holder, struct bio_list *bios)
1070 (holder ? dm_cell_release : dm_cell_release_no_holder)
1071 (cache->prison, cell, bios);
1072 free_prison_cell(cache, cell);
1075 static bool discard_or_flush(struct bio *bio)
1077 return bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD);
1080 static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell)
1082 if (discard_or_flush(cell->holder))
1084 * We have to handle these bios
1087 __cell_release(cache, cell, true, &cache->deferred_bios);
1090 list_add_tail(&cell->user_list, &cache->deferred_cells);
1093 static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, bool holder)
1095 unsigned long flags;
1097 if (!holder && dm_cell_promote_or_release(cache->prison, cell)) {
1099 * There was no prisoner to promote to holder, the
1100 * cell has been released.
1102 free_prison_cell(cache, cell);
1106 spin_lock_irqsave(&cache->lock, flags);
1107 __cell_defer(cache, cell);
1108 spin_unlock_irqrestore(&cache->lock, flags);
1113 static void cell_error_with_code(struct cache *cache, struct dm_bio_prison_cell *cell, int err)
1115 dm_cell_error(cache->prison, cell, err);
1116 dm_bio_prison_free_cell(cache->prison, cell);
1119 static void cell_requeue(struct cache *cache, struct dm_bio_prison_cell *cell)
1121 cell_error_with_code(cache, cell, DM_ENDIO_REQUEUE);
1124 static void free_io_migration(struct dm_cache_migration *mg)
1126 dec_io_migrations(mg->cache);
1130 static void migration_failure(struct dm_cache_migration *mg)
1132 struct cache *cache = mg->cache;
1133 const char *dev_name = cache_device_name(cache);
1135 if (mg->writeback) {
1136 DMERR_LIMIT("%s: writeback failed; couldn't copy block", dev_name);
1137 set_dirty(cache, mg->old_oblock, mg->cblock);
1138 cell_defer(cache, mg->old_ocell, false);
1140 } else if (mg->demote) {
1141 DMERR_LIMIT("%s: demotion failed; couldn't copy block", dev_name);
1142 policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock);
1144 cell_defer(cache, mg->old_ocell, mg->promote ? false : true);
1146 cell_defer(cache, mg->new_ocell, true);
1148 DMERR_LIMIT("%s: promotion failed; couldn't copy block", dev_name);
1149 policy_remove_mapping(cache->policy, mg->new_oblock);
1150 cell_defer(cache, mg->new_ocell, true);
1153 free_io_migration(mg);
1156 static void migration_success_pre_commit(struct dm_cache_migration *mg)
1159 unsigned long flags;
1160 struct cache *cache = mg->cache;
1162 if (mg->writeback) {
1163 clear_dirty(cache, mg->old_oblock, mg->cblock);
1164 cell_defer(cache, mg->old_ocell, false);
1165 free_io_migration(mg);
1168 } else if (mg->demote) {
1169 r = dm_cache_remove_mapping(cache->cmd, mg->cblock);
1171 DMERR_LIMIT("%s: demotion failed; couldn't update on disk metadata",
1172 cache_device_name(cache));
1173 metadata_operation_failed(cache, "dm_cache_remove_mapping", r);
1174 policy_force_mapping(cache->policy, mg->new_oblock,
1177 cell_defer(cache, mg->new_ocell, true);
1178 free_io_migration(mg);
1182 r = dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock);
1184 DMERR_LIMIT("%s: promotion failed; couldn't update on disk metadata",
1185 cache_device_name(cache));
1186 metadata_operation_failed(cache, "dm_cache_insert_mapping", r);
1187 policy_remove_mapping(cache->policy, mg->new_oblock);
1188 free_io_migration(mg);
1193 spin_lock_irqsave(&cache->lock, flags);
1194 list_add_tail(&mg->list, &cache->need_commit_migrations);
1195 cache->commit_requested = true;
1196 spin_unlock_irqrestore(&cache->lock, flags);
1199 static void migration_success_post_commit(struct dm_cache_migration *mg)
1201 unsigned long flags;
1202 struct cache *cache = mg->cache;
1204 if (mg->writeback) {
1205 DMWARN_LIMIT("%s: writeback unexpectedly triggered commit",
1206 cache_device_name(cache));
1209 } else if (mg->demote) {
1210 cell_defer(cache, mg->old_ocell, mg->promote ? false : true);
1215 spin_lock_irqsave(&cache->lock, flags);
1216 list_add_tail(&mg->list, &cache->quiesced_migrations);
1217 spin_unlock_irqrestore(&cache->lock, flags);
1221 policy_remove_mapping(cache->policy, mg->old_oblock);
1222 free_io_migration(mg);
1226 if (mg->requeue_holder) {
1227 clear_dirty(cache, mg->new_oblock, mg->cblock);
1228 cell_defer(cache, mg->new_ocell, true);
1231 * The block was promoted via an overwrite, so it's dirty.
1233 set_dirty(cache, mg->new_oblock, mg->cblock);
1234 bio_endio(mg->new_ocell->holder, 0);
1235 cell_defer(cache, mg->new_ocell, false);
1237 free_io_migration(mg);
1241 static void copy_complete(int read_err, unsigned long write_err, void *context)
1243 unsigned long flags;
1244 struct dm_cache_migration *mg = (struct dm_cache_migration *) context;
1245 struct cache *cache = mg->cache;
1247 if (read_err || write_err)
1250 spin_lock_irqsave(&cache->lock, flags);
1251 list_add_tail(&mg->list, &cache->completed_migrations);
1252 spin_unlock_irqrestore(&cache->lock, flags);
1257 static void issue_copy(struct dm_cache_migration *mg)
1260 struct dm_io_region o_region, c_region;
1261 struct cache *cache = mg->cache;
1262 sector_t cblock = from_cblock(mg->cblock);
1264 o_region.bdev = cache->origin_dev->bdev;
1265 o_region.count = cache->sectors_per_block;
1267 c_region.bdev = cache->cache_dev->bdev;
1268 c_region.sector = cblock * cache->sectors_per_block;
1269 c_region.count = cache->sectors_per_block;
1271 if (mg->writeback || mg->demote) {
1273 o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block;
1274 r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg);
1277 o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block;
1278 r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg);
1282 DMERR_LIMIT("%s: issuing migration failed", cache_device_name(cache));
1283 migration_failure(mg);
1287 static void overwrite_endio(struct bio *bio, int err)
1289 struct dm_cache_migration *mg = bio->bi_private;
1290 struct cache *cache = mg->cache;
1291 size_t pb_data_size = get_per_bio_data_size(cache);
1292 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1293 unsigned long flags;
1295 dm_unhook_bio(&pb->hook_info, bio);
1300 mg->requeue_holder = false;
1302 spin_lock_irqsave(&cache->lock, flags);
1303 list_add_tail(&mg->list, &cache->completed_migrations);
1304 spin_unlock_irqrestore(&cache->lock, flags);
1309 static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio)
1311 size_t pb_data_size = get_per_bio_data_size(mg->cache);
1312 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1314 dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg);
1315 remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock);
1318 * No need to inc_ds() here, since the cell will be held for the
1319 * duration of the io.
1321 accounted_request(mg->cache, bio);
1324 static bool bio_writes_complete_block(struct cache *cache, struct bio *bio)
1326 return (bio_data_dir(bio) == WRITE) &&
1327 (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT));
1330 static void avoid_copy(struct dm_cache_migration *mg)
1332 atomic_inc(&mg->cache->stats.copies_avoided);
1333 migration_success_pre_commit(mg);
1336 static void calc_discard_block_range(struct cache *cache, struct bio *bio,
1337 dm_dblock_t *b, dm_dblock_t *e)
1339 sector_t sb = bio->bi_iter.bi_sector;
1340 sector_t se = bio_end_sector(bio);
1342 *b = to_dblock(dm_sector_div_up(sb, cache->discard_block_size));
1344 if (se - sb < cache->discard_block_size)
1347 *e = to_dblock(block_div(se, cache->discard_block_size));
1350 static void issue_discard(struct dm_cache_migration *mg)
1353 struct bio *bio = mg->new_ocell->holder;
1355 calc_discard_block_range(mg->cache, bio, &b, &e);
1357 set_discard(mg->cache, b);
1358 b = to_dblock(from_dblock(b) + 1);
1362 cell_defer(mg->cache, mg->new_ocell, false);
1366 static void issue_copy_or_discard(struct dm_cache_migration *mg)
1369 struct cache *cache = mg->cache;
1376 if (mg->writeback || mg->demote)
1377 avoid = !is_dirty(cache, mg->cblock) ||
1378 is_discarded_oblock(cache, mg->old_oblock);
1380 struct bio *bio = mg->new_ocell->holder;
1382 avoid = is_discarded_oblock(cache, mg->new_oblock);
1384 if (writeback_mode(&cache->features) &&
1385 !avoid && bio_writes_complete_block(cache, bio)) {
1386 issue_overwrite(mg, bio);
1391 avoid ? avoid_copy(mg) : issue_copy(mg);
1394 static void complete_migration(struct dm_cache_migration *mg)
1397 migration_failure(mg);
1399 migration_success_pre_commit(mg);
1402 static void process_migrations(struct cache *cache, struct list_head *head,
1403 void (*fn)(struct dm_cache_migration *))
1405 unsigned long flags;
1406 struct list_head list;
1407 struct dm_cache_migration *mg, *tmp;
1409 INIT_LIST_HEAD(&list);
1410 spin_lock_irqsave(&cache->lock, flags);
1411 list_splice_init(head, &list);
1412 spin_unlock_irqrestore(&cache->lock, flags);
1414 list_for_each_entry_safe(mg, tmp, &list, list)
1418 static void __queue_quiesced_migration(struct dm_cache_migration *mg)
1420 list_add_tail(&mg->list, &mg->cache->quiesced_migrations);
1423 static void queue_quiesced_migration(struct dm_cache_migration *mg)
1425 unsigned long flags;
1426 struct cache *cache = mg->cache;
1428 spin_lock_irqsave(&cache->lock, flags);
1429 __queue_quiesced_migration(mg);
1430 spin_unlock_irqrestore(&cache->lock, flags);
1435 static void queue_quiesced_migrations(struct cache *cache, struct list_head *work)
1437 unsigned long flags;
1438 struct dm_cache_migration *mg, *tmp;
1440 spin_lock_irqsave(&cache->lock, flags);
1441 list_for_each_entry_safe(mg, tmp, work, list)
1442 __queue_quiesced_migration(mg);
1443 spin_unlock_irqrestore(&cache->lock, flags);
1448 static void check_for_quiesced_migrations(struct cache *cache,
1449 struct per_bio_data *pb)
1451 struct list_head work;
1453 if (!pb->all_io_entry)
1456 INIT_LIST_HEAD(&work);
1457 dm_deferred_entry_dec(pb->all_io_entry, &work);
1459 if (!list_empty(&work))
1460 queue_quiesced_migrations(cache, &work);
1463 static void quiesce_migration(struct dm_cache_migration *mg)
1465 if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list))
1466 queue_quiesced_migration(mg);
1469 static void promote(struct cache *cache, struct prealloc *structs,
1470 dm_oblock_t oblock, dm_cblock_t cblock,
1471 struct dm_bio_prison_cell *cell)
1473 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1476 mg->discard = false;
1477 mg->writeback = false;
1480 mg->requeue_holder = true;
1481 mg->invalidate = false;
1483 mg->new_oblock = oblock;
1484 mg->cblock = cblock;
1485 mg->old_ocell = NULL;
1486 mg->new_ocell = cell;
1487 mg->start_jiffies = jiffies;
1489 inc_io_migrations(cache);
1490 quiesce_migration(mg);
1493 static void writeback(struct cache *cache, struct prealloc *structs,
1494 dm_oblock_t oblock, dm_cblock_t cblock,
1495 struct dm_bio_prison_cell *cell)
1497 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1500 mg->discard = false;
1501 mg->writeback = true;
1503 mg->promote = false;
1504 mg->requeue_holder = true;
1505 mg->invalidate = false;
1507 mg->old_oblock = oblock;
1508 mg->cblock = cblock;
1509 mg->old_ocell = cell;
1510 mg->new_ocell = NULL;
1511 mg->start_jiffies = jiffies;
1513 inc_io_migrations(cache);
1514 quiesce_migration(mg);
1517 static void demote_then_promote(struct cache *cache, struct prealloc *structs,
1518 dm_oblock_t old_oblock, dm_oblock_t new_oblock,
1520 struct dm_bio_prison_cell *old_ocell,
1521 struct dm_bio_prison_cell *new_ocell)
1523 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1526 mg->discard = false;
1527 mg->writeback = false;
1530 mg->requeue_holder = true;
1531 mg->invalidate = false;
1533 mg->old_oblock = old_oblock;
1534 mg->new_oblock = new_oblock;
1535 mg->cblock = cblock;
1536 mg->old_ocell = old_ocell;
1537 mg->new_ocell = new_ocell;
1538 mg->start_jiffies = jiffies;
1540 inc_io_migrations(cache);
1541 quiesce_migration(mg);
1545 * Invalidate a cache entry. No writeback occurs; any changes in the cache
1546 * block are thrown away.
1548 static void invalidate(struct cache *cache, struct prealloc *structs,
1549 dm_oblock_t oblock, dm_cblock_t cblock,
1550 struct dm_bio_prison_cell *cell)
1552 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1555 mg->discard = false;
1556 mg->writeback = false;
1558 mg->promote = false;
1559 mg->requeue_holder = true;
1560 mg->invalidate = true;
1562 mg->old_oblock = oblock;
1563 mg->cblock = cblock;
1564 mg->old_ocell = cell;
1565 mg->new_ocell = NULL;
1566 mg->start_jiffies = jiffies;
1568 inc_io_migrations(cache);
1569 quiesce_migration(mg);
1572 static void discard(struct cache *cache, struct prealloc *structs,
1573 struct dm_bio_prison_cell *cell)
1575 struct dm_cache_migration *mg = prealloc_get_migration(structs);
1579 mg->writeback = false;
1581 mg->promote = false;
1582 mg->requeue_holder = false;
1583 mg->invalidate = false;
1585 mg->old_ocell = NULL;
1586 mg->new_ocell = cell;
1587 mg->start_jiffies = jiffies;
1589 quiesce_migration(mg);
1592 /*----------------------------------------------------------------
1594 *--------------------------------------------------------------*/
1595 static void defer_bio(struct cache *cache, struct bio *bio)
1597 unsigned long flags;
1599 spin_lock_irqsave(&cache->lock, flags);
1600 bio_list_add(&cache->deferred_bios, bio);
1601 spin_unlock_irqrestore(&cache->lock, flags);
1606 static void process_flush_bio(struct cache *cache, struct bio *bio)
1608 size_t pb_data_size = get_per_bio_data_size(cache);
1609 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
1611 BUG_ON(bio->bi_iter.bi_size);
1613 remap_to_origin(cache, bio);
1615 remap_to_cache(cache, bio, 0);
1618 * REQ_FLUSH is not directed at any particular block so we don't
1619 * need to inc_ds(). REQ_FUA's are split into a write + REQ_FLUSH
1625 static void process_discard_bio(struct cache *cache, struct prealloc *structs,
1630 struct dm_bio_prison_cell *cell_prealloc, *new_ocell;
1632 calc_discard_block_range(cache, bio, &b, &e);
1638 cell_prealloc = prealloc_get_cell(structs);
1639 r = bio_detain_range(cache, dblock_to_oblock(cache, b), dblock_to_oblock(cache, e), bio, cell_prealloc,
1640 (cell_free_fn) prealloc_put_cell,
1641 structs, &new_ocell);
1645 discard(cache, structs, new_ocell);
1648 static bool spare_migration_bandwidth(struct cache *cache)
1650 sector_t current_volume = (atomic_read(&cache->nr_io_migrations) + 1) *
1651 cache->sectors_per_block;
1652 return current_volume < cache->migration_threshold;
1655 static void inc_hit_counter(struct cache *cache, struct bio *bio)
1657 atomic_inc(bio_data_dir(bio) == READ ?
1658 &cache->stats.read_hit : &cache->stats.write_hit);
1661 static void inc_miss_counter(struct cache *cache, struct bio *bio)
1663 atomic_inc(bio_data_dir(bio) == READ ?
1664 &cache->stats.read_miss : &cache->stats.write_miss);
1667 /*----------------------------------------------------------------*/
1670 struct cache *cache;
1671 struct bio_list bios_for_issue;
1672 struct bio_list unhandled_bios;
1676 static void inc_fn(void *context, struct dm_bio_prison_cell *cell)
1679 struct inc_detail *detail = context;
1680 struct cache *cache = detail->cache;
1682 inc_ds(cache, cell->holder, cell);
1683 if (bio_data_dir(cell->holder) == WRITE)
1684 detail->any_writes = true;
1686 while ((bio = bio_list_pop(&cell->bios))) {
1687 if (discard_or_flush(bio)) {
1688 bio_list_add(&detail->unhandled_bios, bio);
1692 if (bio_data_dir(bio) == WRITE)
1693 detail->any_writes = true;
1695 bio_list_add(&detail->bios_for_issue, bio);
1696 inc_ds(cache, bio, cell);
1700 // FIXME: refactor these two
1701 static void remap_cell_to_origin_clear_discard(struct cache *cache,
1702 struct dm_bio_prison_cell *cell,
1703 dm_oblock_t oblock, bool issue_holder)
1706 unsigned long flags;
1707 struct inc_detail detail;
1709 detail.cache = cache;
1710 bio_list_init(&detail.bios_for_issue);
1711 bio_list_init(&detail.unhandled_bios);
1712 detail.any_writes = false;
1714 spin_lock_irqsave(&cache->lock, flags);
1715 dm_cell_visit_release(cache->prison, inc_fn, &detail, cell);
1716 bio_list_merge(&cache->deferred_bios, &detail.unhandled_bios);
1717 spin_unlock_irqrestore(&cache->lock, flags);
1719 remap_to_origin(cache, cell->holder);
1721 issue(cache, cell->holder);
1723 accounted_begin(cache, cell->holder);
1725 if (detail.any_writes)
1726 clear_discard(cache, oblock_to_dblock(cache, oblock));
1728 while ((bio = bio_list_pop(&detail.bios_for_issue))) {
1729 remap_to_origin(cache, bio);
1734 static void remap_cell_to_cache_dirty(struct cache *cache, struct dm_bio_prison_cell *cell,
1735 dm_oblock_t oblock, dm_cblock_t cblock, bool issue_holder)
1738 unsigned long flags;
1739 struct inc_detail detail;
1741 detail.cache = cache;
1742 bio_list_init(&detail.bios_for_issue);
1743 bio_list_init(&detail.unhandled_bios);
1744 detail.any_writes = false;
1746 spin_lock_irqsave(&cache->lock, flags);
1747 dm_cell_visit_release(cache->prison, inc_fn, &detail, cell);
1748 bio_list_merge(&cache->deferred_bios, &detail.unhandled_bios);
1749 spin_unlock_irqrestore(&cache->lock, flags);
1751 remap_to_cache(cache, cell->holder, cblock);
1753 issue(cache, cell->holder);
1755 accounted_begin(cache, cell->holder);
1757 if (detail.any_writes) {
1758 set_dirty(cache, oblock, cblock);
1759 clear_discard(cache, oblock_to_dblock(cache, oblock));
1762 while ((bio = bio_list_pop(&detail.bios_for_issue))) {
1763 remap_to_cache(cache, bio, cblock);
1768 /*----------------------------------------------------------------*/
1770 struct old_oblock_lock {
1771 struct policy_locker locker;
1772 struct cache *cache;
1773 struct prealloc *structs;
1774 struct dm_bio_prison_cell *cell;
1777 static int null_locker(struct policy_locker *locker, dm_oblock_t b)
1779 /* This should never be called */
1784 static int cell_locker(struct policy_locker *locker, dm_oblock_t b)
1786 struct old_oblock_lock *l = container_of(locker, struct old_oblock_lock, locker);
1787 struct dm_bio_prison_cell *cell_prealloc = prealloc_get_cell(l->structs);
1789 return bio_detain(l->cache, b, NULL, cell_prealloc,
1790 (cell_free_fn) prealloc_put_cell,
1791 l->structs, &l->cell);
1794 static void process_cell(struct cache *cache, struct prealloc *structs,
1795 struct dm_bio_prison_cell *new_ocell)
1798 bool release_cell = true;
1799 struct bio *bio = new_ocell->holder;
1800 dm_oblock_t block = get_bio_block(cache, bio);
1801 struct policy_result lookup_result;
1802 bool passthrough = passthrough_mode(&cache->features);
1803 bool fast_promotion, can_migrate;
1804 struct old_oblock_lock ool;
1806 fast_promotion = is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio);
1807 can_migrate = !passthrough && (fast_promotion || spare_migration_bandwidth(cache));
1809 ool.locker.fn = cell_locker;
1811 ool.structs = structs;
1813 r = policy_map(cache->policy, block, true, can_migrate, fast_promotion,
1814 bio, &ool.locker, &lookup_result);
1816 if (r == -EWOULDBLOCK)
1817 /* migration has been denied */
1818 lookup_result.op = POLICY_MISS;
1820 switch (lookup_result.op) {
1823 inc_miss_counter(cache, bio);
1826 * Passthrough always maps to the origin,
1827 * invalidating any cache blocks that are written
1831 if (bio_data_dir(bio) == WRITE) {
1832 atomic_inc(&cache->stats.demotion);
1833 invalidate(cache, structs, block, lookup_result.cblock, new_ocell);
1834 release_cell = false;
1837 /* FIXME: factor out issue_origin() */
1838 remap_to_origin_clear_discard(cache, bio, block);
1839 inc_and_issue(cache, bio, new_ocell);
1842 inc_hit_counter(cache, bio);
1844 if (bio_data_dir(bio) == WRITE &&
1845 writethrough_mode(&cache->features) &&
1846 !is_dirty(cache, lookup_result.cblock)) {
1847 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
1848 inc_and_issue(cache, bio, new_ocell);
1851 remap_cell_to_cache_dirty(cache, new_ocell, block, lookup_result.cblock, true);
1852 release_cell = false;
1859 inc_miss_counter(cache, bio);
1860 remap_cell_to_origin_clear_discard(cache, new_ocell, block, true);
1861 release_cell = false;
1865 atomic_inc(&cache->stats.promotion);
1866 promote(cache, structs, block, lookup_result.cblock, new_ocell);
1867 release_cell = false;
1870 case POLICY_REPLACE:
1871 atomic_inc(&cache->stats.demotion);
1872 atomic_inc(&cache->stats.promotion);
1873 demote_then_promote(cache, structs, lookup_result.old_oblock,
1874 block, lookup_result.cblock,
1875 ool.cell, new_ocell);
1876 release_cell = false;
1880 DMERR_LIMIT("%s: %s: erroring bio, unknown policy op: %u",
1881 cache_device_name(cache), __func__,
1882 (unsigned) lookup_result.op);
1887 cell_defer(cache, new_ocell, false);
1890 static void process_bio(struct cache *cache, struct prealloc *structs,
1894 dm_oblock_t block = get_bio_block(cache, bio);
1895 struct dm_bio_prison_cell *cell_prealloc, *new_ocell;
1898 * Check to see if that block is currently migrating.
1900 cell_prealloc = prealloc_get_cell(structs);
1901 r = bio_detain(cache, block, bio, cell_prealloc,
1902 (cell_free_fn) prealloc_put_cell,
1903 structs, &new_ocell);
1907 process_cell(cache, structs, new_ocell);
1910 static int need_commit_due_to_time(struct cache *cache)
1912 return jiffies < cache->last_commit_jiffies ||
1913 jiffies > cache->last_commit_jiffies + COMMIT_PERIOD;
1917 * A non-zero return indicates read_only or fail_io mode.
1919 static int commit(struct cache *cache, bool clean_shutdown)
1923 if (get_cache_mode(cache) >= CM_READ_ONLY)
1926 atomic_inc(&cache->stats.commit_count);
1927 r = dm_cache_commit(cache->cmd, clean_shutdown);
1929 metadata_operation_failed(cache, "dm_cache_commit", r);
1934 static int commit_if_needed(struct cache *cache)
1938 if ((cache->commit_requested || need_commit_due_to_time(cache)) &&
1939 dm_cache_changed_this_transaction(cache->cmd)) {
1940 r = commit(cache, false);
1941 cache->commit_requested = false;
1942 cache->last_commit_jiffies = jiffies;
1948 static void process_deferred_bios(struct cache *cache)
1950 bool prealloc_used = false;
1951 unsigned long flags;
1952 struct bio_list bios;
1954 struct prealloc structs;
1956 memset(&structs, 0, sizeof(structs));
1957 bio_list_init(&bios);
1959 spin_lock_irqsave(&cache->lock, flags);
1960 bio_list_merge(&bios, &cache->deferred_bios);
1961 bio_list_init(&cache->deferred_bios);
1962 spin_unlock_irqrestore(&cache->lock, flags);
1964 while (!bio_list_empty(&bios)) {
1966 * If we've got no free migration structs, and processing
1967 * this bio might require one, we pause until there are some
1968 * prepared mappings to process.
1970 prealloc_used = true;
1971 if (prealloc_data_structs(cache, &structs)) {
1972 spin_lock_irqsave(&cache->lock, flags);
1973 bio_list_merge(&cache->deferred_bios, &bios);
1974 spin_unlock_irqrestore(&cache->lock, flags);
1978 bio = bio_list_pop(&bios);
1980 if (bio->bi_rw & REQ_FLUSH)
1981 process_flush_bio(cache, bio);
1982 else if (bio->bi_rw & REQ_DISCARD)
1983 process_discard_bio(cache, &structs, bio);
1985 process_bio(cache, &structs, bio);
1989 prealloc_free_structs(cache, &structs);
1992 static void process_deferred_cells(struct cache *cache)
1994 bool prealloc_used = false;
1995 unsigned long flags;
1996 struct dm_bio_prison_cell *cell, *tmp;
1997 struct list_head cells;
1998 struct prealloc structs;
2000 memset(&structs, 0, sizeof(structs));
2002 INIT_LIST_HEAD(&cells);
2004 spin_lock_irqsave(&cache->lock, flags);
2005 list_splice_init(&cache->deferred_cells, &cells);
2006 spin_unlock_irqrestore(&cache->lock, flags);
2008 list_for_each_entry_safe(cell, tmp, &cells, user_list) {
2010 * If we've got no free migration structs, and processing
2011 * this bio might require one, we pause until there are some
2012 * prepared mappings to process.
2014 prealloc_used = true;
2015 if (prealloc_data_structs(cache, &structs)) {
2016 spin_lock_irqsave(&cache->lock, flags);
2017 list_splice(&cells, &cache->deferred_cells);
2018 spin_unlock_irqrestore(&cache->lock, flags);
2022 process_cell(cache, &structs, cell);
2026 prealloc_free_structs(cache, &structs);
2029 static void process_deferred_flush_bios(struct cache *cache, bool submit_bios)
2031 unsigned long flags;
2032 struct bio_list bios;
2035 bio_list_init(&bios);
2037 spin_lock_irqsave(&cache->lock, flags);
2038 bio_list_merge(&bios, &cache->deferred_flush_bios);
2039 bio_list_init(&cache->deferred_flush_bios);
2040 spin_unlock_irqrestore(&cache->lock, flags);
2043 * These bios have already been through inc_ds()
2045 while ((bio = bio_list_pop(&bios)))
2046 submit_bios ? accounted_request(cache, bio) : bio_io_error(bio);
2049 static void process_deferred_writethrough_bios(struct cache *cache)
2051 unsigned long flags;
2052 struct bio_list bios;
2055 bio_list_init(&bios);
2057 spin_lock_irqsave(&cache->lock, flags);
2058 bio_list_merge(&bios, &cache->deferred_writethrough_bios);
2059 bio_list_init(&cache->deferred_writethrough_bios);
2060 spin_unlock_irqrestore(&cache->lock, flags);
2063 * These bios have already been through inc_ds()
2065 while ((bio = bio_list_pop(&bios)))
2066 accounted_request(cache, bio);
2069 static void writeback_some_dirty_blocks(struct cache *cache)
2071 bool prealloc_used = false;
2074 struct prealloc structs;
2075 struct dm_bio_prison_cell *old_ocell;
2076 bool busy = !iot_idle_for(&cache->origin_tracker, HZ);
2078 memset(&structs, 0, sizeof(structs));
2080 while (spare_migration_bandwidth(cache)) {
2081 if (policy_writeback_work(cache->policy, &oblock, &cblock, busy))
2082 break; /* no work to do */
2084 prealloc_used = true;
2085 if (prealloc_data_structs(cache, &structs) ||
2086 get_cell(cache, oblock, &structs, &old_ocell)) {
2087 policy_set_dirty(cache->policy, oblock);
2091 writeback(cache, &structs, oblock, cblock, old_ocell);
2095 prealloc_free_structs(cache, &structs);
2098 /*----------------------------------------------------------------
2100 * Dropping something from the cache *without* writing back.
2101 *--------------------------------------------------------------*/
2103 static void process_invalidation_request(struct cache *cache, struct invalidation_request *req)
2106 uint64_t begin = from_cblock(req->cblocks->begin);
2107 uint64_t end = from_cblock(req->cblocks->end);
2109 while (begin != end) {
2110 r = policy_remove_cblock(cache->policy, to_cblock(begin));
2112 r = dm_cache_remove_mapping(cache->cmd, to_cblock(begin));
2114 metadata_operation_failed(cache, "dm_cache_remove_mapping", r);
2118 } else if (r == -ENODATA) {
2119 /* harmless, already unmapped */
2123 DMERR("%s: policy_remove_cblock failed", cache_device_name(cache));
2130 cache->commit_requested = true;
2133 atomic_set(&req->complete, 1);
2135 wake_up(&req->result_wait);
2138 static void process_invalidation_requests(struct cache *cache)
2140 struct list_head list;
2141 struct invalidation_request *req, *tmp;
2143 INIT_LIST_HEAD(&list);
2144 spin_lock(&cache->invalidation_lock);
2145 list_splice_init(&cache->invalidation_requests, &list);
2146 spin_unlock(&cache->invalidation_lock);
2148 list_for_each_entry_safe (req, tmp, &list, list)
2149 process_invalidation_request(cache, req);
2152 /*----------------------------------------------------------------
2154 *--------------------------------------------------------------*/
2155 static bool is_quiescing(struct cache *cache)
2157 return atomic_read(&cache->quiescing);
2160 static void ack_quiescing(struct cache *cache)
2162 if (is_quiescing(cache)) {
2163 atomic_inc(&cache->quiescing_ack);
2164 wake_up(&cache->quiescing_wait);
2168 static void wait_for_quiescing_ack(struct cache *cache)
2170 wait_event(cache->quiescing_wait, atomic_read(&cache->quiescing_ack));
2173 static void start_quiescing(struct cache *cache)
2175 atomic_inc(&cache->quiescing);
2176 wait_for_quiescing_ack(cache);
2179 static void stop_quiescing(struct cache *cache)
2181 atomic_set(&cache->quiescing, 0);
2182 atomic_set(&cache->quiescing_ack, 0);
2185 static void wait_for_migrations(struct cache *cache)
2187 wait_event(cache->migration_wait, !atomic_read(&cache->nr_allocated_migrations));
2190 static void stop_worker(struct cache *cache)
2192 cancel_delayed_work(&cache->waker);
2193 flush_workqueue(cache->wq);
2196 static void requeue_deferred_cells(struct cache *cache)
2198 unsigned long flags;
2199 struct list_head cells;
2200 struct dm_bio_prison_cell *cell, *tmp;
2202 INIT_LIST_HEAD(&cells);
2203 spin_lock_irqsave(&cache->lock, flags);
2204 list_splice_init(&cache->deferred_cells, &cells);
2205 spin_unlock_irqrestore(&cache->lock, flags);
2207 list_for_each_entry_safe(cell, tmp, &cells, user_list)
2208 cell_requeue(cache, cell);
2211 static void requeue_deferred_bios(struct cache *cache)
2214 struct bio_list bios;
2216 bio_list_init(&bios);
2217 bio_list_merge(&bios, &cache->deferred_bios);
2218 bio_list_init(&cache->deferred_bios);
2220 while ((bio = bio_list_pop(&bios)))
2221 bio_endio(bio, DM_ENDIO_REQUEUE);
2224 static int more_work(struct cache *cache)
2226 if (is_quiescing(cache))
2227 return !list_empty(&cache->quiesced_migrations) ||
2228 !list_empty(&cache->completed_migrations) ||
2229 !list_empty(&cache->need_commit_migrations);
2231 return !bio_list_empty(&cache->deferred_bios) ||
2232 !list_empty(&cache->deferred_cells) ||
2233 !bio_list_empty(&cache->deferred_flush_bios) ||
2234 !bio_list_empty(&cache->deferred_writethrough_bios) ||
2235 !list_empty(&cache->quiesced_migrations) ||
2236 !list_empty(&cache->completed_migrations) ||
2237 !list_empty(&cache->need_commit_migrations) ||
2241 static void do_worker(struct work_struct *ws)
2243 struct cache *cache = container_of(ws, struct cache, worker);
2246 if (!is_quiescing(cache)) {
2247 writeback_some_dirty_blocks(cache);
2248 process_deferred_writethrough_bios(cache);
2249 process_deferred_bios(cache);
2250 process_deferred_cells(cache);
2251 process_invalidation_requests(cache);
2254 process_migrations(cache, &cache->quiesced_migrations, issue_copy_or_discard);
2255 process_migrations(cache, &cache->completed_migrations, complete_migration);
2257 if (commit_if_needed(cache)) {
2258 process_deferred_flush_bios(cache, false);
2259 process_migrations(cache, &cache->need_commit_migrations, migration_failure);
2261 process_deferred_flush_bios(cache, true);
2262 process_migrations(cache, &cache->need_commit_migrations,
2263 migration_success_post_commit);
2266 ack_quiescing(cache);
2268 } while (more_work(cache));
2272 * We want to commit periodically so that not too much
2273 * unwritten metadata builds up.
2275 static void do_waker(struct work_struct *ws)
2277 struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker);
2278 policy_tick(cache->policy, true);
2280 queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD);
2283 /*----------------------------------------------------------------*/
2285 static int is_congested(struct dm_dev *dev, int bdi_bits)
2287 struct request_queue *q = bdev_get_queue(dev->bdev);
2288 return bdi_congested(&q->backing_dev_info, bdi_bits);
2291 static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
2293 struct cache *cache = container_of(cb, struct cache, callbacks);
2295 return is_congested(cache->origin_dev, bdi_bits) ||
2296 is_congested(cache->cache_dev, bdi_bits);
2299 /*----------------------------------------------------------------
2301 *--------------------------------------------------------------*/
2304 * This function gets called on the error paths of the constructor, so we
2305 * have to cope with a partially initialised struct.
2307 static void destroy(struct cache *cache)
2311 if (cache->migration_pool)
2312 mempool_destroy(cache->migration_pool);
2314 if (cache->all_io_ds)
2315 dm_deferred_set_destroy(cache->all_io_ds);
2318 dm_bio_prison_destroy(cache->prison);
2321 destroy_workqueue(cache->wq);
2323 if (cache->dirty_bitset)
2324 free_bitset(cache->dirty_bitset);
2326 if (cache->discard_bitset)
2327 free_bitset(cache->discard_bitset);
2330 dm_kcopyd_client_destroy(cache->copier);
2333 dm_cache_metadata_close(cache->cmd);
2335 if (cache->metadata_dev)
2336 dm_put_device(cache->ti, cache->metadata_dev);
2338 if (cache->origin_dev)
2339 dm_put_device(cache->ti, cache->origin_dev);
2341 if (cache->cache_dev)
2342 dm_put_device(cache->ti, cache->cache_dev);
2345 dm_cache_policy_destroy(cache->policy);
2347 for (i = 0; i < cache->nr_ctr_args ; i++)
2348 kfree(cache->ctr_args[i]);
2349 kfree(cache->ctr_args);
2354 static void cache_dtr(struct dm_target *ti)
2356 struct cache *cache = ti->private;
2361 static sector_t get_dev_size(struct dm_dev *dev)
2363 return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
2366 /*----------------------------------------------------------------*/
2369 * Construct a cache device mapping.
2371 * cache <metadata dev> <cache dev> <origin dev> <block size>
2372 * <#feature args> [<feature arg>]*
2373 * <policy> <#policy args> [<policy arg>]*
2375 * metadata dev : fast device holding the persistent metadata
2376 * cache dev : fast device holding cached data blocks
2377 * origin dev : slow device holding original data blocks
2378 * block size : cache unit size in sectors
2380 * #feature args : number of feature arguments passed
2381 * feature args : writethrough. (The default is writeback.)
2383 * policy : the replacement policy to use
2384 * #policy args : an even number of policy arguments corresponding
2385 * to key/value pairs passed to the policy
2386 * policy args : key/value pairs passed to the policy
2387 * E.g. 'sequential_threshold 1024'
2388 * See cache-policies.txt for details.
2390 * Optional feature arguments are:
2391 * writethrough : write through caching that prohibits cache block
2392 * content from being different from origin block content.
2393 * Without this argument, the default behaviour is to write
2394 * back cache block contents later for performance reasons,
2395 * so they may differ from the corresponding origin blocks.
2398 struct dm_target *ti;
2400 struct dm_dev *metadata_dev;
2402 struct dm_dev *cache_dev;
2403 sector_t cache_sectors;
2405 struct dm_dev *origin_dev;
2406 sector_t origin_sectors;
2408 uint32_t block_size;
2410 const char *policy_name;
2412 const char **policy_argv;
2414 struct cache_features features;
2417 static void destroy_cache_args(struct cache_args *ca)
2419 if (ca->metadata_dev)
2420 dm_put_device(ca->ti, ca->metadata_dev);
2423 dm_put_device(ca->ti, ca->cache_dev);
2426 dm_put_device(ca->ti, ca->origin_dev);
2431 static bool at_least_one_arg(struct dm_arg_set *as, char **error)
2434 *error = "Insufficient args";
2441 static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as,
2445 sector_t metadata_dev_size;
2446 char b[BDEVNAME_SIZE];
2448 if (!at_least_one_arg(as, error))
2451 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
2454 *error = "Error opening metadata device";
2458 metadata_dev_size = get_dev_size(ca->metadata_dev);
2459 if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING)
2460 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
2461 bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
2466 static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as,
2471 if (!at_least_one_arg(as, error))
2474 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
2477 *error = "Error opening cache device";
2480 ca->cache_sectors = get_dev_size(ca->cache_dev);
2485 static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as,
2490 if (!at_least_one_arg(as, error))
2493 r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
2496 *error = "Error opening origin device";
2500 ca->origin_sectors = get_dev_size(ca->origin_dev);
2501 if (ca->ti->len > ca->origin_sectors) {
2502 *error = "Device size larger than cached device";
2509 static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as,
2512 unsigned long block_size;
2514 if (!at_least_one_arg(as, error))
2517 if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size ||
2518 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
2519 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
2520 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
2521 *error = "Invalid data block size";
2525 if (block_size > ca->cache_sectors) {
2526 *error = "Data block size is larger than the cache device";
2530 ca->block_size = block_size;
2535 static void init_features(struct cache_features *cf)
2537 cf->mode = CM_WRITE;
2538 cf->io_mode = CM_IO_WRITEBACK;
2541 static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
2544 static struct dm_arg _args[] = {
2545 {0, 1, "Invalid number of cache feature arguments"},
2551 struct cache_features *cf = &ca->features;
2555 r = dm_read_arg_group(_args, as, &argc, error);
2560 arg = dm_shift_arg(as);
2562 if (!strcasecmp(arg, "writeback"))
2563 cf->io_mode = CM_IO_WRITEBACK;
2565 else if (!strcasecmp(arg, "writethrough"))
2566 cf->io_mode = CM_IO_WRITETHROUGH;
2568 else if (!strcasecmp(arg, "passthrough"))
2569 cf->io_mode = CM_IO_PASSTHROUGH;
2572 *error = "Unrecognised cache feature requested";
2580 static int parse_policy(struct cache_args *ca, struct dm_arg_set *as,
2583 static struct dm_arg _args[] = {
2584 {0, 1024, "Invalid number of policy arguments"},
2589 if (!at_least_one_arg(as, error))
2592 ca->policy_name = dm_shift_arg(as);
2594 r = dm_read_arg_group(_args, as, &ca->policy_argc, error);
2598 ca->policy_argv = (const char **)as->argv;
2599 dm_consume_args(as, ca->policy_argc);
2604 static int parse_cache_args(struct cache_args *ca, int argc, char **argv,
2608 struct dm_arg_set as;
2613 r = parse_metadata_dev(ca, &as, error);
2617 r = parse_cache_dev(ca, &as, error);
2621 r = parse_origin_dev(ca, &as, error);
2625 r = parse_block_size(ca, &as, error);
2629 r = parse_features(ca, &as, error);
2633 r = parse_policy(ca, &as, error);
2640 /*----------------------------------------------------------------*/
2642 static struct kmem_cache *migration_cache;
2644 #define NOT_CORE_OPTION 1
2646 static int process_config_option(struct cache *cache, const char *key, const char *value)
2650 if (!strcasecmp(key, "migration_threshold")) {
2651 if (kstrtoul(value, 10, &tmp))
2654 cache->migration_threshold = tmp;
2658 return NOT_CORE_OPTION;
2661 static int set_config_value(struct cache *cache, const char *key, const char *value)
2663 int r = process_config_option(cache, key, value);
2665 if (r == NOT_CORE_OPTION)
2666 r = policy_set_config_value(cache->policy, key, value);
2669 DMWARN("bad config value for %s: %s", key, value);
2674 static int set_config_values(struct cache *cache, int argc, const char **argv)
2679 DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs.");
2684 r = set_config_value(cache, argv[0], argv[1]);
2695 static int create_cache_policy(struct cache *cache, struct cache_args *ca,
2698 struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name,
2700 cache->origin_sectors,
2701 cache->sectors_per_block);
2703 *error = "Error creating cache's policy";
2712 * We want the discard block size to be at least the size of the cache
2713 * block size and have no more than 2^14 discard blocks across the origin.
2715 #define MAX_DISCARD_BLOCKS (1 << 14)
2717 static bool too_many_discard_blocks(sector_t discard_block_size,
2718 sector_t origin_size)
2720 (void) sector_div(origin_size, discard_block_size);
2722 return origin_size > MAX_DISCARD_BLOCKS;
2725 static sector_t calculate_discard_block_size(sector_t cache_block_size,
2726 sector_t origin_size)
2728 sector_t discard_block_size = cache_block_size;
2731 while (too_many_discard_blocks(discard_block_size, origin_size))
2732 discard_block_size *= 2;
2734 return discard_block_size;
2737 static void set_cache_size(struct cache *cache, dm_cblock_t size)
2739 dm_block_t nr_blocks = from_cblock(size);
2741 if (nr_blocks > (1 << 20) && cache->cache_size != size)
2742 DMWARN_LIMIT("You have created a cache device with a lot of individual cache blocks (%llu)\n"
2743 "All these mappings can consume a lot of kernel memory, and take some time to read/write.\n"
2744 "Please consider increasing the cache block size to reduce the overall cache block count.",
2745 (unsigned long long) nr_blocks);
2747 cache->cache_size = size;
2750 #define DEFAULT_MIGRATION_THRESHOLD 2048
2752 static int cache_create(struct cache_args *ca, struct cache **result)
2755 char **error = &ca->ti->error;
2756 struct cache *cache;
2757 struct dm_target *ti = ca->ti;
2758 dm_block_t origin_blocks;
2759 struct dm_cache_metadata *cmd;
2760 bool may_format = ca->features.mode == CM_WRITE;
2762 cache = kzalloc(sizeof(*cache), GFP_KERNEL);
2767 ti->private = cache;
2768 ti->num_flush_bios = 2;
2769 ti->flush_supported = true;
2771 ti->num_discard_bios = 1;
2772 ti->discards_supported = true;
2773 ti->discard_zeroes_data_unsupported = true;
2774 ti->split_discard_bios = false;
2776 cache->features = ca->features;
2777 ti->per_bio_data_size = get_per_bio_data_size(cache);
2779 cache->callbacks.congested_fn = cache_is_congested;
2780 dm_table_add_target_callbacks(ti->table, &cache->callbacks);
2782 cache->metadata_dev = ca->metadata_dev;
2783 cache->origin_dev = ca->origin_dev;
2784 cache->cache_dev = ca->cache_dev;
2786 ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL;
2788 /* FIXME: factor out this whole section */
2789 origin_blocks = cache->origin_sectors = ca->origin_sectors;
2790 origin_blocks = block_div(origin_blocks, ca->block_size);
2791 cache->origin_blocks = to_oblock(origin_blocks);
2793 cache->sectors_per_block = ca->block_size;
2794 if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) {
2799 if (ca->block_size & (ca->block_size - 1)) {
2800 dm_block_t cache_size = ca->cache_sectors;
2802 cache->sectors_per_block_shift = -1;
2803 cache_size = block_div(cache_size, ca->block_size);
2804 set_cache_size(cache, to_cblock(cache_size));
2806 cache->sectors_per_block_shift = __ffs(ca->block_size);
2807 set_cache_size(cache, to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift));
2810 r = create_cache_policy(cache, ca, error);
2814 cache->policy_nr_args = ca->policy_argc;
2815 cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD;
2817 r = set_config_values(cache, ca->policy_argc, ca->policy_argv);
2819 *error = "Error setting cache policy's config values";
2823 cmd = dm_cache_metadata_open(cache->metadata_dev->bdev,
2824 ca->block_size, may_format,
2825 dm_cache_policy_get_hint_size(cache->policy));
2827 *error = "Error creating metadata object";
2832 set_cache_mode(cache, CM_WRITE);
2833 if (get_cache_mode(cache) != CM_WRITE) {
2834 *error = "Unable to get write access to metadata, please check/repair metadata.";
2839 if (passthrough_mode(&cache->features)) {
2842 r = dm_cache_metadata_all_clean(cache->cmd, &all_clean);
2844 *error = "dm_cache_metadata_all_clean() failed";
2849 *error = "Cannot enter passthrough mode unless all blocks are clean";
2855 spin_lock_init(&cache->lock);
2856 INIT_LIST_HEAD(&cache->deferred_cells);
2857 bio_list_init(&cache->deferred_bios);
2858 bio_list_init(&cache->deferred_flush_bios);
2859 bio_list_init(&cache->deferred_writethrough_bios);
2860 INIT_LIST_HEAD(&cache->quiesced_migrations);
2861 INIT_LIST_HEAD(&cache->completed_migrations);
2862 INIT_LIST_HEAD(&cache->need_commit_migrations);
2863 atomic_set(&cache->nr_allocated_migrations, 0);
2864 atomic_set(&cache->nr_io_migrations, 0);
2865 init_waitqueue_head(&cache->migration_wait);
2867 init_waitqueue_head(&cache->quiescing_wait);
2868 atomic_set(&cache->quiescing, 0);
2869 atomic_set(&cache->quiescing_ack, 0);
2872 atomic_set(&cache->nr_dirty, 0);
2873 cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size));
2874 if (!cache->dirty_bitset) {
2875 *error = "could not allocate dirty bitset";
2878 clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
2880 cache->discard_block_size =
2881 calculate_discard_block_size(cache->sectors_per_block,
2882 cache->origin_sectors);
2883 cache->discard_nr_blocks = to_dblock(dm_sector_div_up(cache->origin_sectors,
2884 cache->discard_block_size));
2885 cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks));
2886 if (!cache->discard_bitset) {
2887 *error = "could not allocate discard bitset";
2890 clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));
2892 cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2893 if (IS_ERR(cache->copier)) {
2894 *error = "could not create kcopyd client";
2895 r = PTR_ERR(cache->copier);
2899 cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2901 *error = "could not create workqueue for metadata object";
2904 INIT_WORK(&cache->worker, do_worker);
2905 INIT_DELAYED_WORK(&cache->waker, do_waker);
2906 cache->last_commit_jiffies = jiffies;
2908 cache->prison = dm_bio_prison_create();
2909 if (!cache->prison) {
2910 *error = "could not create bio prison";
2914 cache->all_io_ds = dm_deferred_set_create();
2915 if (!cache->all_io_ds) {
2916 *error = "could not create all_io deferred set";
2920 cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE,
2922 if (!cache->migration_pool) {
2923 *error = "Error creating cache's migration mempool";
2927 cache->need_tick_bio = true;
2928 cache->sized = false;
2929 cache->invalidate = false;
2930 cache->commit_requested = false;
2931 cache->loaded_mappings = false;
2932 cache->loaded_discards = false;
2936 atomic_set(&cache->stats.demotion, 0);
2937 atomic_set(&cache->stats.promotion, 0);
2938 atomic_set(&cache->stats.copies_avoided, 0);
2939 atomic_set(&cache->stats.cache_cell_clash, 0);
2940 atomic_set(&cache->stats.commit_count, 0);
2941 atomic_set(&cache->stats.discard_count, 0);
2943 spin_lock_init(&cache->invalidation_lock);
2944 INIT_LIST_HEAD(&cache->invalidation_requests);
2946 iot_init(&cache->origin_tracker);
2956 static int copy_ctr_args(struct cache *cache, int argc, const char **argv)
2961 copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL);
2964 for (i = 0; i < argc; i++) {
2965 copy[i] = kstrdup(argv[i], GFP_KERNEL);
2974 cache->nr_ctr_args = argc;
2975 cache->ctr_args = copy;
2980 static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv)
2983 struct cache_args *ca;
2984 struct cache *cache = NULL;
2986 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2988 ti->error = "Error allocating memory for cache";
2993 r = parse_cache_args(ca, argc, argv, &ti->error);
2997 r = cache_create(ca, &cache);
3001 r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3);
3007 ti->private = cache;
3010 destroy_cache_args(ca);
3014 /*----------------------------------------------------------------*/
3016 static int cache_map(struct dm_target *ti, struct bio *bio)
3018 struct cache *cache = ti->private;
3021 struct dm_bio_prison_cell *cell = NULL;
3022 dm_oblock_t block = get_bio_block(cache, bio);
3023 size_t pb_data_size = get_per_bio_data_size(cache);
3024 bool can_migrate = false;
3025 bool fast_promotion;
3026 struct policy_result lookup_result;
3027 struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size);
3028 struct old_oblock_lock ool;
3030 ool.locker.fn = null_locker;
3032 if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) {
3034 * This can only occur if the io goes to a partial block at
3035 * the end of the origin device. We don't cache these.
3036 * Just remap to the origin and carry on.
3038 remap_to_origin(cache, bio);
3039 accounted_begin(cache, bio);
3040 return DM_MAPIO_REMAPPED;
3043 if (discard_or_flush(bio)) {
3044 defer_bio(cache, bio);
3045 return DM_MAPIO_SUBMITTED;
3049 * Check to see if that block is currently migrating.
3051 cell = alloc_prison_cell(cache);
3053 defer_bio(cache, bio);
3054 return DM_MAPIO_SUBMITTED;
3057 r = bio_detain(cache, block, bio, cell,
3058 (cell_free_fn) free_prison_cell,
3062 defer_bio(cache, bio);
3064 return DM_MAPIO_SUBMITTED;
3067 fast_promotion = is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio);
3069 r = policy_map(cache->policy, block, false, can_migrate, fast_promotion,
3070 bio, &ool.locker, &lookup_result);
3071 if (r == -EWOULDBLOCK) {
3072 cell_defer(cache, cell, true);
3073 return DM_MAPIO_SUBMITTED;
3076 DMERR_LIMIT("%s: Unexpected return from cache replacement policy: %d",
3077 cache_device_name(cache), r);
3078 cell_defer(cache, cell, false);
3080 return DM_MAPIO_SUBMITTED;
3083 r = DM_MAPIO_REMAPPED;
3084 switch (lookup_result.op) {
3086 if (passthrough_mode(&cache->features)) {
3087 if (bio_data_dir(bio) == WRITE) {
3089 * We need to invalidate this block, so
3090 * defer for the worker thread.
3092 cell_defer(cache, cell, true);
3093 r = DM_MAPIO_SUBMITTED;
3096 inc_miss_counter(cache, bio);
3097 remap_to_origin_clear_discard(cache, bio, block);
3098 accounted_begin(cache, bio);
3099 inc_ds(cache, bio, cell);
3100 // FIXME: we want to remap hits or misses straight
3101 // away rather than passing over to the worker.
3102 cell_defer(cache, cell, false);
3106 inc_hit_counter(cache, bio);
3107 if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) &&
3108 !is_dirty(cache, lookup_result.cblock)) {
3109 remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock);
3110 accounted_begin(cache, bio);
3111 inc_ds(cache, bio, cell);
3112 cell_defer(cache, cell, false);
3115 remap_cell_to_cache_dirty(cache, cell, block, lookup_result.cblock, false);
3120 inc_miss_counter(cache, bio);
3121 if (pb->req_nr != 0) {
3123 * This is a duplicate writethrough io that is no
3124 * longer needed because the block has been demoted.
3127 // FIXME: remap everything as a miss
3128 cell_defer(cache, cell, false);
3129 r = DM_MAPIO_SUBMITTED;
3132 remap_cell_to_origin_clear_discard(cache, cell, block, false);
3136 DMERR_LIMIT("%s: %s: erroring bio: unknown policy op: %u",
3137 cache_device_name(cache), __func__,
3138 (unsigned) lookup_result.op);
3139 cell_defer(cache, cell, false);
3141 r = DM_MAPIO_SUBMITTED;
3147 static int cache_end_io(struct dm_target *ti, struct bio *bio, int error)
3149 struct cache *cache = ti->private;
3150 unsigned long flags;
3151 size_t pb_data_size = get_per_bio_data_size(cache);
3152 struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);
3155 policy_tick(cache->policy, false);
3157 spin_lock_irqsave(&cache->lock, flags);
3158 cache->need_tick_bio = true;
3159 spin_unlock_irqrestore(&cache->lock, flags);
3162 check_for_quiesced_migrations(cache, pb);
3163 accounted_complete(cache, bio);
3168 static int write_dirty_bitset(struct cache *cache)
3172 if (get_cache_mode(cache) >= CM_READ_ONLY)
3175 for (i = 0; i < from_cblock(cache->cache_size); i++) {
3176 r = dm_cache_set_dirty(cache->cmd, to_cblock(i),
3177 is_dirty(cache, to_cblock(i)));
3179 metadata_operation_failed(cache, "dm_cache_set_dirty", r);
3187 static int write_discard_bitset(struct cache *cache)
3191 if (get_cache_mode(cache) >= CM_READ_ONLY)
3194 r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size,
3195 cache->discard_nr_blocks);
3197 DMERR("%s: could not resize on-disk discard bitset", cache_device_name(cache));
3198 metadata_operation_failed(cache, "dm_cache_discard_bitset_resize", r);
3202 for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) {
3203 r = dm_cache_set_discard(cache->cmd, to_dblock(i),
3204 is_discarded(cache, to_dblock(i)));
3206 metadata_operation_failed(cache, "dm_cache_set_discard", r);
3214 static int write_hints(struct cache *cache)
3218 if (get_cache_mode(cache) >= CM_READ_ONLY)
3221 r = dm_cache_write_hints(cache->cmd, cache->policy);
3223 metadata_operation_failed(cache, "dm_cache_write_hints", r);
3231 * returns true on success
3233 static bool sync_metadata(struct cache *cache)
3237 r1 = write_dirty_bitset(cache);
3239 DMERR("%s: could not write dirty bitset", cache_device_name(cache));
3241 r2 = write_discard_bitset(cache);
3243 DMERR("%s: could not write discard bitset", cache_device_name(cache));
3247 r3 = write_hints(cache);
3249 DMERR("%s: could not write hints", cache_device_name(cache));
3252 * If writing the above metadata failed, we still commit, but don't
3253 * set the clean shutdown flag. This will effectively force every
3254 * dirty bit to be set on reload.
3256 r4 = commit(cache, !r1 && !r2 && !r3);
3258 DMERR("%s: could not write cache metadata", cache_device_name(cache));
3260 return !r1 && !r2 && !r3 && !r4;
3263 static void cache_postsuspend(struct dm_target *ti)
3265 struct cache *cache = ti->private;
3267 start_quiescing(cache);
3268 wait_for_migrations(cache);
3270 requeue_deferred_bios(cache);
3271 requeue_deferred_cells(cache);
3272 stop_quiescing(cache);
3274 if (get_cache_mode(cache) == CM_WRITE)
3275 (void) sync_metadata(cache);
3278 static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
3279 bool dirty, uint32_t hint, bool hint_valid)
3282 struct cache *cache = context;
3284 r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid);
3289 set_dirty(cache, oblock, cblock);
3291 clear_dirty(cache, oblock, cblock);
3297 * The discard block size in the on disk metadata is not
3298 * neccessarily the same as we're currently using. So we have to
3299 * be careful to only set the discarded attribute if we know it
3300 * covers a complete block of the new size.
3302 struct discard_load_info {
3303 struct cache *cache;
3306 * These blocks are sized using the on disk dblock size, rather
3307 * than the current one.
3309 dm_block_t block_size;
3310 dm_block_t discard_begin, discard_end;
3313 static void discard_load_info_init(struct cache *cache,
3314 struct discard_load_info *li)
3317 li->discard_begin = li->discard_end = 0;
3320 static void set_discard_range(struct discard_load_info *li)
3324 if (li->discard_begin == li->discard_end)
3328 * Convert to sectors.
3330 b = li->discard_begin * li->block_size;
3331 e = li->discard_end * li->block_size;
3334 * Then convert back to the current dblock size.
3336 b = dm_sector_div_up(b, li->cache->discard_block_size);
3337 sector_div(e, li->cache->discard_block_size);
3340 * The origin may have shrunk, so we need to check we're still in
3343 if (e > from_dblock(li->cache->discard_nr_blocks))
3344 e = from_dblock(li->cache->discard_nr_blocks);
3347 set_discard(li->cache, to_dblock(b));
3350 static int load_discard(void *context, sector_t discard_block_size,
3351 dm_dblock_t dblock, bool discard)
3353 struct discard_load_info *li = context;
3355 li->block_size = discard_block_size;
3358 if (from_dblock(dblock) == li->discard_end)
3360 * We're already in a discard range, just extend it.
3362 li->discard_end = li->discard_end + 1ULL;
3366 * Emit the old range and start a new one.
3368 set_discard_range(li);
3369 li->discard_begin = from_dblock(dblock);
3370 li->discard_end = li->discard_begin + 1ULL;
3373 set_discard_range(li);
3374 li->discard_begin = li->discard_end = 0;
3380 static dm_cblock_t get_cache_dev_size(struct cache *cache)
3382 sector_t size = get_dev_size(cache->cache_dev);
3383 (void) sector_div(size, cache->sectors_per_block);
3384 return to_cblock(size);
3387 static bool can_resize(struct cache *cache, dm_cblock_t new_size)
3389 if (from_cblock(new_size) > from_cblock(cache->cache_size))
3393 * We can't drop a dirty block when shrinking the cache.
3395 while (from_cblock(new_size) < from_cblock(cache->cache_size)) {
3396 new_size = to_cblock(from_cblock(new_size) + 1);
3397 if (is_dirty(cache, new_size)) {
3398 DMERR("%s: unable to shrink cache; cache block %llu is dirty",
3399 cache_device_name(cache),
3400 (unsigned long long) from_cblock(new_size));
3408 static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size)
3412 r = dm_cache_resize(cache->cmd, new_size);
3414 DMERR("%s: could not resize cache metadata", cache_device_name(cache));
3415 metadata_operation_failed(cache, "dm_cache_resize", r);
3419 set_cache_size(cache, new_size);
3424 static int cache_preresume(struct dm_target *ti)
3427 struct cache *cache = ti->private;
3428 dm_cblock_t csize = get_cache_dev_size(cache);
3431 * Check to see if the cache has resized.
3433 if (!cache->sized) {
3434 r = resize_cache_dev(cache, csize);
3438 cache->sized = true;
3440 } else if (csize != cache->cache_size) {
3441 if (!can_resize(cache, csize))
3444 r = resize_cache_dev(cache, csize);
3449 if (!cache->loaded_mappings) {
3450 r = dm_cache_load_mappings(cache->cmd, cache->policy,
3451 load_mapping, cache);
3453 DMERR("%s: could not load cache mappings", cache_device_name(cache));
3454 metadata_operation_failed(cache, "dm_cache_load_mappings", r);
3458 cache->loaded_mappings = true;
3461 if (!cache->loaded_discards) {
3462 struct discard_load_info li;
3465 * The discard bitset could have been resized, or the
3466 * discard block size changed. To be safe we start by
3467 * setting every dblock to not discarded.
3469 clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));
3471 discard_load_info_init(cache, &li);
3472 r = dm_cache_load_discards(cache->cmd, load_discard, &li);
3474 DMERR("%s: could not load origin discards", cache_device_name(cache));
3475 metadata_operation_failed(cache, "dm_cache_load_discards", r);
3478 set_discard_range(&li);
3480 cache->loaded_discards = true;
3486 static void cache_resume(struct dm_target *ti)
3488 struct cache *cache = ti->private;
3490 cache->need_tick_bio = true;
3491 do_waker(&cache->waker.work);
3497 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
3498 * <cache block size> <#used cache blocks>/<#total cache blocks>
3499 * <#read hits> <#read misses> <#write hits> <#write misses>
3500 * <#demotions> <#promotions> <#dirty>
3501 * <#features> <features>*
3502 * <#core args> <core args>
3503 * <policy name> <#policy args> <policy args>* <cache metadata mode> <needs_check>
3505 static void cache_status(struct dm_target *ti, status_type_t type,
3506 unsigned status_flags, char *result, unsigned maxlen)
3511 dm_block_t nr_free_blocks_metadata = 0;
3512 dm_block_t nr_blocks_metadata = 0;
3513 char buf[BDEVNAME_SIZE];
3514 struct cache *cache = ti->private;
3515 dm_cblock_t residency;
3518 case STATUSTYPE_INFO:
3519 if (get_cache_mode(cache) == CM_FAIL) {
3524 /* Commit to ensure statistics aren't out-of-date */
3525 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3526 (void) commit(cache, false);
3528 r = dm_cache_get_free_metadata_block_count(cache->cmd, &nr_free_blocks_metadata);
3530 DMERR("%s: dm_cache_get_free_metadata_block_count returned %d",
3531 cache_device_name(cache), r);
3535 r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata);
3537 DMERR("%s: dm_cache_get_metadata_dev_size returned %d",
3538 cache_device_name(cache), r);
3542 residency = policy_residency(cache->policy);
3544 DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %lu ",
3545 (unsigned)DM_CACHE_METADATA_BLOCK_SIZE,
3546 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3547 (unsigned long long)nr_blocks_metadata,
3548 cache->sectors_per_block,
3549 (unsigned long long) from_cblock(residency),
3550 (unsigned long long) from_cblock(cache->cache_size),
3551 (unsigned) atomic_read(&cache->stats.read_hit),
3552 (unsigned) atomic_read(&cache->stats.read_miss),
3553 (unsigned) atomic_read(&cache->stats.write_hit),
3554 (unsigned) atomic_read(&cache->stats.write_miss),
3555 (unsigned) atomic_read(&cache->stats.demotion),
3556 (unsigned) atomic_read(&cache->stats.promotion),
3557 (unsigned long) atomic_read(&cache->nr_dirty));
3559 if (writethrough_mode(&cache->features))
3560 DMEMIT("1 writethrough ");
3562 else if (passthrough_mode(&cache->features))
3563 DMEMIT("1 passthrough ");
3565 else if (writeback_mode(&cache->features))
3566 DMEMIT("1 writeback ");
3569 DMERR("%s: internal error: unknown io mode: %d",
3570 cache_device_name(cache), (int) cache->features.io_mode);
3574 DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);
3576 DMEMIT("%s ", dm_cache_policy_get_name(cache->policy));
3578 r = policy_emit_config_values(cache->policy, result, maxlen, &sz);
3580 DMERR("%s: policy_emit_config_values returned %d",
3581 cache_device_name(cache), r);
3584 if (get_cache_mode(cache) == CM_READ_ONLY)
3589 if (dm_cache_metadata_needs_check(cache->cmd))
3590 DMEMIT("needs_check ");
3596 case STATUSTYPE_TABLE:
3597 format_dev_t(buf, cache->metadata_dev->bdev->bd_dev);
3599 format_dev_t(buf, cache->cache_dev->bdev->bd_dev);
3601 format_dev_t(buf, cache->origin_dev->bdev->bd_dev);
3604 for (i = 0; i < cache->nr_ctr_args - 1; i++)
3605 DMEMIT(" %s", cache->ctr_args[i]);
3606 if (cache->nr_ctr_args)
3607 DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]);
3617 * A cache block range can take two forms:
3619 * i) A single cblock, eg. '3456'
3620 * ii) A begin and end cblock with dots between, eg. 123-234
3622 static int parse_cblock_range(struct cache *cache, const char *str,
3623 struct cblock_range *result)
3630 * Try and parse form (ii) first.
3632 r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy);
3637 result->begin = to_cblock(b);
3638 result->end = to_cblock(e);
3643 * That didn't work, try form (i).
3645 r = sscanf(str, "%llu%c", &b, &dummy);
3650 result->begin = to_cblock(b);
3651 result->end = to_cblock(from_cblock(result->begin) + 1u);
3655 DMERR("%s: invalid cblock range '%s'", cache_device_name(cache), str);
3659 static int validate_cblock_range(struct cache *cache, struct cblock_range *range)
3661 uint64_t b = from_cblock(range->begin);
3662 uint64_t e = from_cblock(range->end);
3663 uint64_t n = from_cblock(cache->cache_size);
3666 DMERR("%s: begin cblock out of range: %llu >= %llu",
3667 cache_device_name(cache), b, n);
3672 DMERR("%s: end cblock out of range: %llu > %llu",
3673 cache_device_name(cache), e, n);
3678 DMERR("%s: invalid cblock range: %llu >= %llu",
3679 cache_device_name(cache), b, e);
3686 static int request_invalidation(struct cache *cache, struct cblock_range *range)
3688 struct invalidation_request req;
3690 INIT_LIST_HEAD(&req.list);
3691 req.cblocks = range;
3692 atomic_set(&req.complete, 0);
3694 init_waitqueue_head(&req.result_wait);
3696 spin_lock(&cache->invalidation_lock);
3697 list_add(&req.list, &cache->invalidation_requests);
3698 spin_unlock(&cache->invalidation_lock);
3701 wait_event(req.result_wait, atomic_read(&req.complete));
3705 static int process_invalidate_cblocks_message(struct cache *cache, unsigned count,
3706 const char **cblock_ranges)
3710 struct cblock_range range;
3712 if (!passthrough_mode(&cache->features)) {
3713 DMERR("%s: cache has to be in passthrough mode for invalidation",
3714 cache_device_name(cache));
3718 for (i = 0; i < count; i++) {
3719 r = parse_cblock_range(cache, cblock_ranges[i], &range);
3723 r = validate_cblock_range(cache, &range);
3728 * Pass begin and end origin blocks to the worker and wake it.
3730 r = request_invalidation(cache, &range);
3742 * "invalidate_cblocks [(<begin>)|(<begin>-<end>)]*
3744 * The key migration_threshold is supported by the cache target core.
3746 static int cache_message(struct dm_target *ti, unsigned argc, char **argv)
3748 struct cache *cache = ti->private;
3753 if (get_cache_mode(cache) >= CM_READ_ONLY) {
3754 DMERR("%s: unable to service cache target messages in READ_ONLY or FAIL mode",
3755 cache_device_name(cache));
3759 if (!strcasecmp(argv[0], "invalidate_cblocks"))
3760 return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1);
3765 return set_config_value(cache, argv[0], argv[1]);
3768 static int cache_iterate_devices(struct dm_target *ti,
3769 iterate_devices_callout_fn fn, void *data)
3772 struct cache *cache = ti->private;
3774 r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data);
3776 r = fn(ti, cache->origin_dev, 0, ti->len, data);
3782 * We assume I/O is going to the origin (which is the volume
3783 * more likely to have restrictions e.g. by being striped).
3784 * (Looking up the exact location of the data would be expensive
3785 * and could always be out of date by the time the bio is submitted.)
3787 static int cache_bvec_merge(struct dm_target *ti,
3788 struct bvec_merge_data *bvm,
3789 struct bio_vec *biovec, int max_size)
3791 struct cache *cache = ti->private;
3792 struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev);
3794 if (!q->merge_bvec_fn)
3797 bvm->bi_bdev = cache->origin_dev->bdev;
3798 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3801 static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
3804 * FIXME: these limits may be incompatible with the cache device
3806 limits->max_discard_sectors = min_t(sector_t, cache->discard_block_size * 1024,
3807 cache->origin_sectors);
3808 limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
3811 static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
3813 struct cache *cache = ti->private;
3814 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
3817 * If the system-determined stacked limits are compatible with the
3818 * cache's blocksize (io_opt is a factor) do not override them.
3820 if (io_opt_sectors < cache->sectors_per_block ||
3821 do_div(io_opt_sectors, cache->sectors_per_block)) {
3822 blk_limits_io_min(limits, cache->sectors_per_block << SECTOR_SHIFT);
3823 blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
3825 set_discard_limits(cache, limits);
3828 /*----------------------------------------------------------------*/
3830 static struct target_type cache_target = {
3832 .version = {1, 8, 0},
3833 .module = THIS_MODULE,
3837 .end_io = cache_end_io,
3838 .postsuspend = cache_postsuspend,
3839 .preresume = cache_preresume,
3840 .resume = cache_resume,
3841 .status = cache_status,
3842 .message = cache_message,
3843 .iterate_devices = cache_iterate_devices,
3844 .merge = cache_bvec_merge,
3845 .io_hints = cache_io_hints,
3848 static int __init dm_cache_init(void)
3852 r = dm_register_target(&cache_target);
3854 DMERR("cache target registration failed: %d", r);
3858 migration_cache = KMEM_CACHE(dm_cache_migration, 0);
3859 if (!migration_cache) {
3860 dm_unregister_target(&cache_target);
3867 static void __exit dm_cache_exit(void)
3869 dm_unregister_target(&cache_target);
3870 kmem_cache_destroy(migration_cache);
3873 module_init(dm_cache_init);
3874 module_exit(dm_cache_exit);
3876 MODULE_DESCRIPTION(DM_NAME " cache target");
3877 MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
3878 MODULE_LICENSE("GPL");