diff options
Diffstat (limited to 'drivers/md/dm-cache-target.c')
| -rw-r--r-- | drivers/md/dm-cache-target.c | 2469 |
1 files changed, 1081 insertions, 1388 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 2eaa414e1509..b7de289a10bb 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -5,7 +5,7 @@ */ #include "dm.h" -#include "dm-bio-prison-v1.h" +#include "dm-bio-prison-v2.h" #include "dm-bio-record.h" #include "dm-cache-metadata.h" @@ -15,6 +15,7 @@ #include <linux/init.h> #include <linux/mempool.h> #include <linux/module.h> +#include <linux/rwsem.h> #include <linux/slab.h> #include <linux/vmalloc.h> @@ -25,7 +26,18 @@ DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle, /*----------------------------------------------------------------*/ -#define IOT_RESOLUTION 4 +/* + * Glossary: + * + * oblock: index of an origin block + * cblock: index of a cache block + * promotion: movement of a block from origin to cache + * demotion: movement of a block from cache to origin + * migration: movement of a block between the origin and cache device, + * either direction + */ + +/*----------------------------------------------------------------*/ struct io_tracker { spinlock_t lock; @@ -99,19 +111,178 @@ static void iot_io_end(struct io_tracker *iot, sector_t len) /*----------------------------------------------------------------*/ /* - * Glossary: - * - * oblock: index of an origin block - * cblock: index of a cache block - * promotion: movement of a block from origin to cache - * demotion: movement of a block from cache to origin - * migration: movement of a block between the origin and cache device, - * either direction + * Represents a chunk of future work. 'input' allows continuations to pass + * values between themselves, typically error values. */ +struct continuation { + struct work_struct ws; + int input; +}; + +static inline void init_continuation(struct continuation *k, + void (*fn)(struct work_struct *)) +{ + INIT_WORK(&k->ws, fn); + k->input = 0; +} + +static inline void queue_continuation(struct workqueue_struct *wq, + struct continuation *k) +{ + queue_work(wq, &k->ws); +} /*----------------------------------------------------------------*/ /* + * The batcher collects together pieces of work that need a particular + * operation to occur before they can proceed (typically a commit). + */ +struct batcher { + /* + * The operation that everyone is waiting for. + */ + int (*commit_op)(void *context); + void *commit_context; + + /* + * This is how bios should be issued once the commit op is complete + * (accounted_request). + */ + void (*issue_op)(struct bio *bio, void *context); + void *issue_context; + + /* + * Queued work gets put on here after commit. + */ + struct workqueue_struct *wq; + + spinlock_t lock; + struct list_head work_items; + struct bio_list bios; + struct work_struct commit_work; + + bool commit_scheduled; +}; + +static void __commit(struct work_struct *_ws) +{ + struct batcher *b = container_of(_ws, struct batcher, commit_work); + + int r; + unsigned long flags; + struct list_head work_items; + struct work_struct *ws, *tmp; + struct continuation *k; + struct bio *bio; + struct bio_list bios; + + INIT_LIST_HEAD(&work_items); + bio_list_init(&bios); + + /* + * We have to grab these before the commit_op to avoid a race + * condition. + */ + spin_lock_irqsave(&b->lock, flags); + list_splice_init(&b->work_items, &work_items); + bio_list_merge(&bios, &b->bios); + bio_list_init(&b->bios); + b->commit_scheduled = false; + spin_unlock_irqrestore(&b->lock, flags); + + r = b->commit_op(b->commit_context); + + list_for_each_entry_safe(ws, tmp, &work_items, entry) { + k = container_of(ws, struct continuation, ws); + k->input = r; + INIT_LIST_HEAD(&ws->entry); /* to avoid a WARN_ON */ + queue_work(b->wq, ws); + } + + while ((bio = bio_list_pop(&bios))) { + if (r) { + bio->bi_error = r; + bio_endio(bio); + } else + b->issue_op(bio, b->issue_context); + } +} + +static void batcher_init(struct batcher *b, + int (*commit_op)(void *), + void *commit_context, + void (*issue_op)(struct bio *bio, void *), + void *issue_context, + struct workqueue_struct *wq) +{ + b->commit_op = commit_op; + b->commit_context = commit_context; + b->issue_op = issue_op; + b->issue_context = issue_context; + b->wq = wq; + + spin_lock_init(&b->lock); + INIT_LIST_HEAD(&b->work_items); + bio_list_init(&b->bios); + INIT_WORK(&b->commit_work, __commit); + b->commit_scheduled = false; +} + +static void async_commit(struct batcher *b) +{ + queue_work(b->wq, &b->commit_work); +} + +static void continue_after_commit(struct batcher *b, struct continuation *k) +{ + unsigned long flags; + bool commit_scheduled; + + spin_lock_irqsave(&b->lock, flags); + commit_scheduled = b->commit_scheduled; + list_add_tail(&k->ws.entry, &b->work_items); + spin_unlock_irqrestore(&b->lock, flags); + + if (commit_scheduled) + async_commit(b); +} + +/* + * Bios are errored if commit failed. + */ +static void issue_after_commit(struct batcher *b, struct bio *bio) +{ + unsigned long flags; + bool commit_scheduled; + + spin_lock_irqsave(&b->lock, flags); + commit_scheduled = b->commit_scheduled; + bio_list_add(&b->bios, bio); + spin_unlock_irqrestore(&b->lock, flags); + + if (commit_scheduled) + async_commit(b); +} + +/* + * Call this if some urgent work is waiting for the commit to complete. + */ +static void schedule_commit(struct batcher *b) +{ + bool immediate; + unsigned long flags; + + spin_lock_irqsave(&b->lock, flags); + immediate = !list_empty(&b->work_items) || !bio_list_empty(&b->bios); + b->commit_scheduled = true; + spin_unlock_irqrestore(&b->lock, flags); + + if (immediate) + async_commit(b); +} + +/* * There are a couple of places where we let a bio run, but want to do some * work before calling its endio function. We do this by temporarily * changing the endio fn. @@ -189,31 +360,13 @@ struct cache_stats { atomic_t write_miss; atomic_t demotion; atomic_t promotion; + atomic_t writeback; atomic_t copies_avoided; atomic_t cache_cell_clash; atomic_t commit_count; atomic_t discard_count; }; -/* - * Defines a range of cblocks, begin to (end - 1) are in the range. end is - * the one-past-the-end value. - */ -struct cblock_range { - dm_cblock_t begin; - dm_cblock_t end; -}; - -struct invalidation_request { - struct list_head list; - struct cblock_range *cblocks; - - atomic_t complete; - int err; - - wait_queue_head_t result_wait; -}; - struct cache { struct dm_target *ti; struct dm_target_callbacks callbacks; @@ -255,11 +408,7 @@ struct cache { spinlock_t lock; struct list_head deferred_cells; struct bio_list deferred_bios; - struct bio_list deferred_flush_bios; struct bio_list deferred_writethrough_bios; - struct list_head quiesced_migrations; - struct list_head completed_migrations; - struct list_head need_commit_migrations; sector_t migration_threshold; wait_queue_head_t migration_wait; atomic_t nr_allocated_migrations; @@ -270,9 +419,7 @@ struct cache { */ atomic_t nr_io_migrations; - wait_queue_head_t quiescing_wait; - atomic_t quiescing; - atomic_t quiescing_ack; + struct rw_semaphore quiesce_lock; /* * cache_size entries, dirty if set @@ -296,13 +443,11 @@ struct cache { struct dm_kcopyd_client *copier; struct workqueue_struct *wq; - struct work_struct worker; - + struct work_struct deferred_bio_worker; + struct work_struct deferred_writethrough_worker; + struct work_struct migration_worker; struct delayed_work waker; - unsigned long last_commit_jiffies; - - struct dm_bio_prison *prison; - struct dm_deferred_set *all_io_ds; + struct dm_bio_prison_v2 *prison; mempool_t *migration_pool; @@ -330,12 +475,17 @@ struct cache { struct list_head invalidation_requests; struct io_tracker origin_tracker; + + struct work_struct commit_ws; + struct batcher committer; + + struct rw_semaphore background_work_lock; }; struct per_bio_data { bool tick:1; unsigned req_nr:2; - struct dm_deferred_entry *all_io_entry; + struct dm_bio_prison_cell_v2 *cell; struct dm_hook_info hook_info; sector_t len; @@ -350,55 +500,64 @@ struct per_bio_data { }; struct dm_cache_migration { - struct list_head list; + struct continuation k; struct cache *cache; - unsigned long start_jiffies; - dm_oblock_t old_oblock; - dm_oblock_t new_oblock; - dm_cblock_t cblock; - - bool err:1; - bool discard:1; - bool writeback:1; - bool demote:1; - bool promote:1; - bool requeue_holder:1; - bool invalidate:1; + struct policy_work *op; + struct bio *overwrite_bio; + struct dm_bio_prison_cell_v2 *cell; - struct dm_bio_prison_cell *old_ocell; - struct dm_bio_prison_cell *new_ocell; + dm_cblock_t invalidate_cblock; + dm_oblock_t invalidate_oblock; }; -/* - * Processing a bio in the worker thread may require these memory - * allocations. We prealloc to avoid deadlocks (the same worker thread - * frees them back to the mempool). - */ -struct prealloc { - struct dm_cache_migration *mg; - struct dm_bio_prison_cell *cell1; - struct dm_bio_prison_cell *cell2; -}; +/*----------------------------------------------------------------*/ + +static bool writethrough_mode(struct cache_features *f) +{ + return f->io_mode == CM_IO_WRITETHROUGH; +} -static enum cache_metadata_mode get_cache_mode(struct cache *cache); +static bool writeback_mode(struct cache_features *f) +{ + return f->io_mode == CM_IO_WRITEBACK; +} -static void wake_worker(struct cache *cache) +static inline bool passthrough_mode(struct cache_features *f) { - queue_work(cache->wq, &cache->worker); + return unlikely(f->io_mode == CM_IO_PASSTHROUGH); } /*----------------------------------------------------------------*/ -static struct dm_bio_prison_cell *alloc_prison_cell(struct cache *cache) +static void wake_deferred_bio_worker(struct cache *cache) { - /* FIXME: change to use a local slab. */ - return dm_bio_prison_alloc_cell(cache->prison, GFP_NOWAIT); + queue_work(cache->wq, &cache->deferred_bio_worker); } -static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cell) +static void wake_deferred_writethrough_worker(struct cache *cache) { - dm_bio_prison_free_cell(cache->prison, cell); + queue_work(cache->wq, &cache->deferred_writethrough_worker); +} + +static void wake_migration_worker(struct cache *cache) +{ + if (passthrough_mode(&cache->features)) + return; + + queue_work(cache->wq, &cache->migration_worker); +} + +/*----------------------------------------------------------------*/ + +static struct dm_bio_prison_cell_v2 *alloc_prison_cell(struct cache *cache) +{ + return dm_bio_prison_alloc_cell_v2(cache->prison, GFP_NOWAIT); +} + +static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell_v2 *cell) +{ + dm_bio_prison_free_cell_v2(cache->prison, cell); } static struct dm_cache_migration *alloc_migration(struct cache *cache) @@ -424,146 +583,127 @@ static void free_migration(struct dm_cache_migration *mg) mempool_free(mg, cache->migration_pool); } -static int prealloc_data_structs(struct cache *cache, struct prealloc *p) -{ - if (!p->mg) { - p->mg = alloc_migration(cache); - if (!p->mg) - return -ENOMEM; - } - - if (!p->cell1) { - p->cell1 = alloc_prison_cell(cache); - if (!p->cell1) - return -ENOMEM; - } - - if (!p->cell2) { - p->cell2 = alloc_prison_cell(cache); - if (!p->cell2) - return -ENOMEM; - } - - return 0; -} +/*----------------------------------------------------------------*/ -static void prealloc_free_structs(struct cache *cache, struct prealloc *p) +static inline dm_oblock_t oblock_succ(dm_oblock_t b) { - if (p->cell2) - free_prison_cell(cache, p->cell2); - - if (p->cell1) - free_prison_cell(cache, p->cell1); - - if (p->mg) - free_migration(p->mg); + return to_oblock(from_oblock(b) + 1ull); } -static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p) +static void build_key(dm_oblock_t begin, dm_oblock_t end, struct dm_cell_key_v2 *key) { - struct dm_cache_migration *mg = p->mg; - - BUG_ON(!mg); - p->mg = NULL; - - return mg; + key->virtual = 0; + key->dev = 0; + key->block_begin = from_oblock(begin); + key->block_end = from_oblock(end); } /* - * You must have a cell within the prealloc struct to return. If not this - * function will BUG() rather than returning NULL. + * We have two lock levels. Level 0, which is used to prevent WRITEs, and + * level 1 which prevents *both* READs and WRITEs. */ -static struct dm_bio_prison_cell *prealloc_get_cell(struct prealloc *p) +#define WRITE_LOCK_LEVEL 0 +#define READ_WRITE_LOCK_LEVEL 1 + +static unsigned lock_level(struct bio *bio) { - struct dm_bio_prison_cell *r = NULL; + return bio_data_dir(bio) == WRITE ? + WRITE_LOCK_LEVEL : + READ_WRITE_LOCK_LEVEL; +} - if (p->cell1) { - r = p->cell1; - p->cell1 = NULL; +/*---------------------------------------------------------------- + * Per bio data + *--------------------------------------------------------------*/ - } else if (p->cell2) { - r = p->cell2; - p->cell2 = NULL; - } else - BUG(); +/* + * If using writeback, leave out struct per_bio_data's writethrough fields. + */ +#define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) +#define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) - return r; +static size_t get_per_bio_data_size(struct cache *cache) +{ + return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; } -/* - * You can't have more than two cells in a prealloc struct. BUG() will be - * called if you try and overfill. - */ -static void prealloc_put_cell(struct prealloc *p, struct dm_bio_prison_cell *cell) +static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size) { - if (!p->cell2) - p->cell2 = cell; + struct per_bio_data *pb = dm_per_bio_data(bio, data_size); + BUG_ON(!pb); + return pb; +} - else if (!p->cell1) - p->cell1 = cell; +static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size) +{ + struct per_bio_data *pb = get_per_bio_data(bio, data_size); - else - BUG(); + pb->tick = false; + pb->req_nr = dm_bio_get_target_bio_nr(bio); + pb->cell = NULL; + pb->len = 0; + + return pb; } /*----------------------------------------------------------------*/ -static void build_key(dm_oblock_t begin, dm_oblock_t end, struct dm_cell_key *key) +static void defer_bio(struct cache *cache, struct bio *bio) { - key->virtual = 0; - key->dev = 0; - key->block_begin = from_oblock(begin); - key->block_end = from_oblock(end); -} + unsigned long flags; -/* - * The caller hands in a preallocated cell, and a free function for it. - * The cell will be freed if there's an error, or if it wasn't used because - * a cell with that key already exists. - */ -typedef void (*cell_free_fn)(void *context, struct dm_bio_prison_cell *cell); + spin_lock_irqsave(&cache->lock, flags); + bio_list_add(&cache->deferred_bios, bio); + spin_unlock_irqrestore(&cache->lock, flags); -static int bio_detain_range(struct cache *cache, dm_oblock_t oblock_begin, dm_oblock_t oblock_end, - struct bio *bio, struct dm_bio_prison_cell *cell_prealloc, - cell_free_fn free_fn, void *free_context, - struct dm_bio_prison_cell **cell_result) + wake_deferred_bio_worker(cache); +} + +static void defer_bios(struct cache *cache, struct bio_list *bios) { - int r; - struct dm_cell_key key; + unsigned long flags; - build_key(oblock_begin, oblock_end, &key); - r = dm_bio_detain(cache->prison, &key, bio, cell_prealloc, cell_result); - if (r) - free_fn(free_context, cell_prealloc); + spin_lock_irqsave(&cache->lock, flags); + bio_list_merge(&cache->deferred_bios, bios); + bio_list_init(bios); + spin_unlock_irqrestore(&cache->lock, flags); - return r; + wake_deferred_bio_worker(cache); } -static int bio_detain(struct cache *cache, dm_oblock_t oblock, - struct bio *bio, struct dm_bio_prison_cell *cell_prealloc, - cell_free_fn free_fn, void *free_context, - struct dm_bio_prison_cell **cell_result) +/*----------------------------------------------------------------*/ + +static bool bio_detain_shared(struct cache *cache, dm_oblock_t oblock, struct bio *bio) { + bool r; + size_t pb_size; + struct per_bio_data *pb; + struct dm_cell_key_v2 key; dm_oblock_t end = to_oblock(from_oblock(oblock) + 1ULL); - return bio_detain_range(cache, oblock, end, bio, - cell_prealloc, free_fn, free_context, cell_result); -} + struct dm_bio_prison_cell_v2 *cell_prealloc, *cell; -static int get_cell(struct cache *cache, - dm_oblock_t oblock, - struct prealloc *structs, - struct dm_bio_prison_cell **cell_result) -{ - int r; - struct dm_cell_key key; - struct dm_bio_prison_cell *cell_prealloc; + cell_prealloc = alloc_prison_cell(cache); /* FIXME: allow wait if calling from worker */ + if (!cell_prealloc) { + defer_bio(cache, bio); + return false; + } - cell_prealloc = prealloc_get_cell(structs); + build_key(oblock, end, &key); + r = dm_cell_get_v2(cache->prison, &key, lock_level(bio), bio, cell_prealloc, &cell); + if (!r) { + /* + * Failed to get the lock. + */ + free_prison_cell(cache, cell_prealloc); + return r; + } - build_key(oblock, to_oblock(from_oblock(oblock) + 1ULL), &key); - r = dm_get_cell(cache->prison, &key, cell_prealloc, cell_result); - if (r) - prealloc_put_cell(structs, cell_prealloc); + if (cell != cell_prealloc) + free_prison_cell(cache, cell_prealloc); + + pb_size = get_per_bio_data_size(cache); + pb = get_per_bio_data(bio, pb_size); + pb->cell = cell; return r; } @@ -575,21 +715,33 @@ static bool is_dirty(struct cache *cache, dm_cblock_t b) return test_bit(from_cblock(b), cache->dirty_bitset); } -static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) +static void set_dirty(struct cache *cache, dm_cblock_t cblock) { if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) { atomic_inc(&cache->nr_dirty); - policy_set_dirty(cache->policy, oblock); + policy_set_dirty(cache->policy, cblock); } } -static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) +/* + * These two are called when setting after migrations to force the policy + * and dirty bitset to be in sync. + */ +static void force_set_dirty(struct cache *cache, dm_cblock_t cblock) +{ + if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) + atomic_inc(&cache->nr_dirty); + policy_set_dirty(cache->policy, cblock); +} + +static void force_clear_dirty(struct cache *cache, dm_cblock_t cblock) { if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) { - policy_clear_dirty(cache->policy, oblock); if (atomic_dec_return(&cache->nr_dirty) == 0) dm_table_event(cache->ti->table); } + + policy_clear_dirty(cache->policy, cblock); } /*----------------------------------------------------------------*/ @@ -628,11 +780,6 @@ static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) oblocks_per_dblock(cache))); } -static dm_oblock_t dblock_to_oblock(struct cache *cache, dm_dblock_t dblock) -{ - return to_oblock(from_dblock(dblock) * oblocks_per_dblock(cache)); -} - static void set_discard(struct cache *cache, dm_dblock_t b) { unsigned long flags; @@ -679,83 +826,6 @@ static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) return r; } -/*----------------------------------------------------------------*/ - -static void load_stats(struct cache *cache) -{ - struct dm_cache_statistics stats; - - dm_cache_metadata_get_stats(cache->cmd, &stats); - atomic_set(&cache->stats.read_hit, stats.read_hits); - atomic_set(&cache->stats.read_miss, stats.read_misses); - atomic_set(&cache->stats.write_hit, stats.write_hits); - atomic_set(&cache->stats.write_miss, stats.write_misses); -} - -static void save_stats(struct cache *cache) -{ - struct dm_cache_statistics stats; - - if (get_cache_mode(cache) >= CM_READ_ONLY) - return; - - stats.read_hits = atomic_read(&cache->stats.read_hit); - stats.read_misses = atomic_read(&cache->stats.read_miss); - stats.write_hits = atomic_read(&cache->stats.write_hit); - stats.write_misses = atomic_read(&cache->stats.write_miss); - - dm_cache_metadata_set_stats(cache->cmd, &stats); -} - -/*---------------------------------------------------------------- - * Per bio data - *--------------------------------------------------------------*/ - -/* - * If using writeback, leave out struct per_bio_data's writethrough fields. - */ -#define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) -#define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) - -static bool writethrough_mode(struct cache_features *f) -{ - return f->io_mode == CM_IO_WRITETHROUGH; -} - -static bool writeback_mode(struct cache_features *f) -{ - return f->io_mode == CM_IO_WRITEBACK; -} - -static bool passthrough_mode(struct cache_features *f) -{ - return f->io_mode == CM_IO_PASSTHROUGH; -} - -static size_t get_per_bio_data_size(struct cache *cache) -{ - return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; -} - -static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size) -{ - struct per_bio_data *pb = dm_per_bio_data(bio, data_size); - BUG_ON(!pb); - return pb; -} - -static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size) -{ - struct per_bio_data *pb = get_per_bio_data(bio, data_size); - - pb->tick = false; - pb->req_nr = dm_bio_get_target_bio_nr(bio); - pb->all_io_entry = NULL; - pb->len = 0; - - return pb; -} - /*---------------------------------------------------------------- * Remapping *--------------------------------------------------------------*/ @@ -797,8 +867,9 @@ static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) } static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, - dm_oblock_t oblock) + dm_oblock_t oblock) { + // FIXME: this is called way too much. check_if_tick_bio_needed(cache, bio); remap_to_origin(cache, bio); if (bio_data_dir(bio) == WRITE) @@ -811,7 +882,7 @@ static void remap_to_cache_dirty(struct cache *cache, struct bio *bio, check_if_tick_bio_needed(cache, bio); remap_to_cache(cache, bio, cblock); if (bio_data_dir(bio) == WRITE) { - set_dirty(cache, oblock, cblock); + set_dirty(cache, cblock); clear_discard(cache, oblock_to_dblock(cache, oblock)); } } @@ -828,22 +899,6 @@ static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) return to_oblock(block_nr); } -/* - * You must increment the deferred set whilst the prison cell is held. To - * encourage this, we ask for 'cell' to be passed in. - */ -static void inc_ds(struct cache *cache, struct bio *bio, - struct dm_bio_prison_cell *cell) -{ - size_t pb_data_size = get_per_bio_data_size(cache); - struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); - - BUG_ON(!cell); - BUG_ON(pb->all_io_entry); - - pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); -} - static bool accountable_bio(struct cache *cache, struct bio *bio) { return ((bio->bi_bdev == cache->origin_dev->bdev) && @@ -875,29 +930,10 @@ static void accounted_request(struct cache *cache, struct bio *bio) generic_make_request(bio); } -static void issue(struct cache *cache, struct bio *bio) +static void issue_op(struct bio *bio, void *context) { - unsigned long flags; - - if (!op_is_flush(bio->bi_opf)) { - accounted_request(cache, bio); - return; - } - - /* - * Batch together any bios that trigger commits and then issue a - * single commit for them in do_worker(). - */ - spin_lock_irqsave(&cache->lock, flags); - cache->commit_requested = true; - bio_list_add(&cache->deferred_flush_bios, bio); - spin_unlock_irqrestore(&cache->lock, flags); -} - -static void inc_and_issue(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell *cell) -{ - inc_ds(cache, bio, cell); - issue(cache, bio); + struct cache *cache = context; + accounted_request(cache, bio); } static void defer_writethrough_bio(struct cache *cache, struct bio *bio) @@ -908,7 +944,7 @@ static void defer_writethrough_bio(struct cache *cache, struct bio *bio) bio_list_add(&cache->deferred_writethrough_bios, bio); spin_unlock_irqrestore(&cache->lock, flags); - wake_worker(cache); + wake_deferred_writethrough_worker(cache); } static void writethrough_endio(struct bio *bio) @@ -934,6 +970,7 @@ static void writethrough_endio(struct bio *bio) } /* + * FIXME: send in parallel, huge latency as is. * When running in writethrough mode we need to send writes to clean blocks * to both the cache and origin devices. In future we'd like to clone the * bio and send them in parallel, but for now we're doing them in @@ -1046,12 +1083,58 @@ static void metadata_operation_failed(struct cache *cache, const char *op, int r set_cache_mode(cache, CM_READ_ONLY); } +/*----------------------------------------------------------------*/ + +static void load_stats(struct cache *cache) +{ + struct dm_cache_statistics stats; + + dm_cache_metadata_get_stats(cache->cmd, &stats); + atomic_set(&cache->stats.read_hit, stats.read_hits); + atomic_set(&cache->stats.read_miss, stats.read_misses); + atomic_set(&cache->stats.write_hit, stats.write_hits); + atomic_set(&cache->stats.write_miss, stats.write_misses); +} + +static void save_stats(struct cache *cache) +{ + struct dm_cache_statistics stats; + + if (get_cache_mode(cache) >= CM_READ_ONLY) + return; + + stats.read_hits = atomic_read(&cache->stats.read_hit); + stats.read_misses = atomic_read(&cache->stats.read_miss); + stats.write_hits = atomic_read(&cache->stats.write_hit); + stats.write_misses = atomic_read(&cache->stats.write_miss); + + dm_cache_metadata_set_stats(cache->cmd, &stats); +} + +static void update_stats(struct cache_stats *stats, enum policy_operation op) +{ + switch (op) { + case POLICY_PROMOTE: + atomic_inc(&stats->promotion); + break; + + case POLICY_DEMOTE: + atomic_inc(&stats->demotion); + break; + + case POLICY_WRITEBACK: + atomic_inc(&stats->writeback); + break; + } +} + /*---------------------------------------------------------------- * Migration processing * * Migration covers moving data from the origin device to the cache, or * vice versa. *--------------------------------------------------------------*/ + static void inc_io_migrations(struct cache *cache) { atomic_inc(&cache->nr_io_migrations); @@ -1067,213 +1150,109 @@ static bool discard_or_flush(struct bio *bio) return bio_op(bio) == REQ_OP_DISCARD || op_is_flush(bio->bi_opf); } -static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell) -{ - if (discard_or_flush(cell->holder)) { - /* - * We have to handle these bios individually. - */ - dm_cell_release(cache->prison, cell, &cache->deferred_bios); - free_prison_cell(cache, cell); - } else - list_add_tail(&cell->user_list, &cache->deferred_cells); -} - -static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, bool holder) +static void calc_discard_block_range(struct cache *cache, struct bio *bio, + dm_dblock_t *b, dm_dblock_t *e) { - unsigned long flags; - - if (!holder && dm_cell_promote_or_release(cache->prison, cell)) { - /* - * There was no prisoner to promote to holder, the - * cell has been released. - */ - free_prison_cell(cache, cell); - return; - } + sector_t sb = bio->bi_iter.bi_sector; + sector_t se = bio_end_sector(bio); - spin_lock_irqsave(&cache->lock, flags); - __cell_defer(cache, cell); - spin_unlock_irqrestore(&cache->lock, flags); + *b = to_dblock(dm_sector_div_up(sb, cache->discard_block_size)); - wake_worker(cache); + if (se - sb < cache->discard_block_size) + *e = *b; + else + *e = to_dblock(block_div(se, cache->discard_block_size)); } -static void cell_error_with_code(struct cache *cache, struct dm_bio_prison_cell *cell, int err) -{ - dm_cell_error(cache->prison, cell, err); - free_prison_cell(cache, cell); -} +/*----------------------------------------------------------------*/ -static void cell_requeue(struct cache *cache, struct dm_bio_prison_cell *cell) +static void prevent_background_work(struct cache *cache) { - cell_error_with_code(cache, cell, DM_ENDIO_REQUEUE); + lockdep_off(); + down_write(&cache->background_work_lock); + lockdep_on(); } -static void free_io_migration(struct dm_cache_migration *mg) +static void allow_background_work(struct cache *cache) { - struct cache *cache = mg->cache; - - dec_io_migrations(cache); - free_migration(mg); - wake_worker(cache); + lockdep_off(); + up_write(&cache->background_work_lock); + lockdep_on(); } -static void migration_failure(struct dm_cache_migration *mg) +static bool background_work_begin(struct cache *cache) { - struct cache *cache = mg->cache; - const char *dev_name = cache_device_name(cache); - - if (mg->writeback) { - DMERR_LIMIT("%s: writeback failed; couldn't copy block", dev_name); - set_dirty(cache, mg->old_oblock, mg->cblock); - cell_defer(cache, mg->old_ocell, false); - - } else if (mg->demote) { - DMERR_LIMIT("%s: demotion failed; couldn't copy block", dev_name); - policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); + bool r; - cell_defer(cache, mg->old_ocell, mg->promote ? false : true); - if (mg->promote) - cell_defer(cache, mg->new_ocell, true); - } else { - DMERR_LIMIT("%s: promotion failed; couldn't copy block", dev_name); - policy_remove_mapping(cache->policy, mg->new_oblock); - cell_defer(cache, mg->new_ocell, true); - } + lockdep_off(); + r = down_read_trylock(&cache->background_work_lock); + lockdep_on(); - free_io_migration(mg); + return r; } -static void migration_success_pre_commit(struct dm_cache_migration *mg) +static void background_work_end(struct cache *cache) { - int r; - unsigned long flags; - struct cache *cache = mg->cache; - - if (mg->writeback) { - clear_dirty(cache, mg->old_oblock, mg->cblock); - cell_defer(cache, mg->old_ocell, false); - free_io_migration(mg); - return; + lockdep_off(); + up_read(&cache->background_work_lock); + lockdep_on(); +} - } else if (mg->demote) { - r = dm_cache_remove_mapping(cache->cmd, mg->cblock); - if (r) { - DMERR_LIMIT("%s: demotion failed; couldn't update on disk metadata", - cache_device_name(cache)); - metadata_operation_failed(cache, "dm_cache_remove_mapping", r); - policy_force_mapping(cache->policy, mg->new_oblock, - mg->old_oblock); - if (mg->promote) - cell_defer(cache, mg->new_ocell, true); - free_io_migration(mg); - return; - } - } else { - r = dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock); - if (r) { - DMERR_LIMIT("%s: promotion failed; couldn't update on disk metadata", - cache_device_name(cache)); - metadata_operation_failed(cache, "dm_cache_insert_mapping", r); - policy_remove_mapping(cache->policy, mg->new_oblock); - free_io_migration(mg); - return; - } - } +/*----------------------------------------------------------------*/ - spin_lock_irqsave(&cache->lock, flags); - list_add_tail(&mg->list, &cache->need_commit_migrations); - cache->commit_requested = true; - spin_unlock_irqrestore(&cache->lock, flags); +static void quiesce(struct dm_cache_migration *mg, + void (*continuation)(struct work_struct *)) +{ + init_continuation(&mg->k, continuation); + dm_cell_quiesce_v2(mg->cache->prison, mg->cell, &mg->k.ws); } -static void migration_success_post_commit(struct dm_cache_migration *mg) +static struct dm_cache_migration *ws_to_mg(struct work_struct *ws) { - unsigned long flags; - struct cache *cache = mg->cache; - - if (mg->writeback) { - DMWARN_LIMIT("%s: writeback unexpectedly triggered commit", - cache_device_name(cache)); - return; - - } else if (mg->demote) { - cell_defer(cache, mg->old_ocell, mg->promote ? false : true); - - if (mg->promote) { - mg->demote = false; - - spin_lock_irqsave(&cache->lock, flags); - list_add_tail(&mg->list, &cache->quiesced_migrations); - spin_unlock_irqrestore(&cache->lock, flags); - - } else { - if (mg->invalidate) - policy_remove_mapping(cache->policy, mg->old_oblock); - free_io_migration(mg); - } - - } else { - if (mg->requeue_holder) { - clear_dirty(cache, mg->new_oblock, mg->cblock); - cell_defer(cache, mg->new_ocell, true); - } else { - /* - * The block was promoted via an overwrite, so it's dirty. - */ - set_dirty(cache, mg->new_oblock, mg->cblock); - bio_endio(mg->new_ocell->holder); - cell_defer(cache, mg->new_ocell, false); - } - free_io_migration(mg); - } + struct continuation *k = container_of(ws, struct continuation, ws); + return container_of(k, struct dm_cache_migration, k); } static void copy_complete(int read_err, unsigned long write_err, void *context) { - unsigned long flags; - struct dm_cache_migration *mg = (struct dm_cache_migration *) context; - struct cache *cache = mg->cache; + struct dm_cache_migration *mg = container_of(context, struct dm_cache_migration, k); if (read_err || write_err) - mg->err = true; - - spin_lock_irqsave(&cache->lock, flags); - list_add_tail(&mg->list, &cache->completed_migrations); - spin_unlock_irqrestore(&cache->lock, flags); + mg->k.input = -EIO; - wake_worker(cache); + queue_continuation(mg->cache->wq, &mg->k); } -static void issue_copy(struct dm_cache_migration *mg) +static int copy(struct dm_cache_migration *mg, bool promote) { int r; struct dm_io_region o_region, c_region; struct cache *cache = mg->cache; - sector_t cblock = from_cblock(mg->cblock); o_region.bdev = cache->origin_dev->bdev; + o_region.sector = from_oblock(mg->op->oblock) * cache->sectors_per_block; o_region.count = cache->sectors_per_block; c_region.bdev = cache->cache_dev->bdev; - c_region.sector = cblock * cache->sectors_per_block; + c_region.sector = from_cblock(mg->op->cblock) * cache->sectors_per_block; c_region.count = cache->sectors_per_block; - if (mg->writeback || mg->demote) { - /* demote */ - o_region.sector = from_oblock(mg->old_oblock) * cache->sectors_per_block; - r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, mg); - } else { - /* promote */ - o_region.sector = from_oblock(mg->new_oblock) * cache->sectors_per_block; - r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg); - } + if (promote) + r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, &mg->k); + else + r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, &mg->k); - if (r < 0) { - DMERR_LIMIT("%s: issuing migration failed", cache_device_name(cache)); - migration_failure(mg); - } + return r; +} + +static void bio_drop_shared_lock(struct cache *cache, struct bio *bio) +{ + size_t pb_data_size = get_per_bio_data_size(cache); + struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); + + if (pb->cell && dm_cell_put_v2(cache->prison, pb->cell)) + free_prison_cell(cache, pb->cell); + pb->cell = NULL; } static void overwrite_endio(struct bio *bio) @@ -1282,368 +1261,475 @@ static void overwrite_endio(struct bio *bio) struct cache *cache = mg->cache; size_t pb_data_size = get_per_bio_data_size(cache); struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); - unsigned long flags; dm_unhook_bio(&pb->hook_info, bio); if (bio->bi_error) - mg->err = true; + mg->k.input = bio->bi_error; - mg->requeue_holder = false; - - spin_lock_irqsave(&cache->lock, flags); - list_add_tail(&mg->list, &cache->completed_migrations); - spin_unlock_irqrestore(&cache->lock, flags); - - wake_worker(cache); + queue_continuation(mg->cache->wq, &mg->k); } -static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio) +static void overwrite(struct dm_cache_migration *mg, + void (*continuation)(struct work_struct *)) { + struct bio *bio = mg->overwrite_bio; size_t pb_data_size = get_per_bio_data_size(mg->cache); struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg); - remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock); /* - * No need to inc_ds() here, since the cell will be held for the - * duration of the io. + * The overwrite bio is part of the copy operation, as such it does + * not set/clear discard or dirty flags. */ + if (mg->op->op == POLICY_PROMOTE) + remap_to_cache(mg->cache, bio, mg->op->cblock); + else + remap_to_origin(mg->cache, bio); + + init_continuation(&mg->k, continuation); accounted_request(mg->cache, bio); } -static bool bio_writes_complete_block(struct cache *cache, struct bio *bio) +/* + * Migration steps: + * + * 1) exclusive lock preventing WRITEs + * 2) quiesce + * 3) copy or issue overwrite bio + * 4) upgrade to exclusive lock preventing READs and WRITEs + * 5) quiesce + * 6) update metadata and commit + * 7) unlock + */ +static void mg_complete(struct dm_cache_migration *mg, bool success) { - return (bio_data_dir(bio) == WRITE) && - (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT)); -} + struct bio_list bios; + struct cache *cache = mg->cache; + struct policy_work *op = mg->op; + dm_cblock_t cblock = op->cblock; + + if (success) + update_stats(&cache->stats, op->op); + + switch (op->op) { + case POLICY_PROMOTE: + clear_discard(cache, oblock_to_dblock(cache, op->oblock)); + policy_complete_background_work(cache->policy, op, success); + + if (mg->overwrite_bio) { + if (success) + force_set_dirty(cache, cblock); + else + mg->overwrite_bio->bi_error = (mg->k.input ? : -EIO); + bio_endio(mg->overwrite_bio); + } else { + if (success) + force_clear_dirty(cache, cblock); + dec_io_migrations(cache); + } + break; -static void avoid_copy(struct dm_cache_migration *mg) -{ - atomic_inc(&mg->cache->stats.copies_avoided); - migration_success_pre_commit(mg); -} + case POLICY_DEMOTE: + /* + * We clear dirty here to update the nr_dirty counter. + */ + if (success) + force_clear_dirty(cache, cblock); + policy_complete_background_work(cache->policy, op, success); + dec_io_migrations(cache); + break; -static void calc_discard_block_range(struct cache *cache, struct bio *bio, - dm_dblock_t *b, dm_dblock_t *e) -{ - sector_t sb = bio->bi_iter.bi_sector; - sector_t se = bio_end_sector(bio); + case POLICY_WRITEBACK: + if (success) + force_clear_dirty(cache, cblock); + policy_complete_background_work(cache->policy, op, success); + dec_io_migrations(cache); + break; + } - *b = to_dblock(dm_sector_div_up(sb, cache->discard_block_size)); + bio_list_init(&bios); + if (mg->cell) { + if (dm_cell_unlock_v2(cache->prison, mg->cell, &bios)) + free_prison_cell(cache, mg->cell); + } - if (se - sb < cache->discard_block_size) - *e = *b; - else - *e = to_dblock(block_div(se, cache->discard_block_size)); + free_migration(mg); + defer_bios(cache, &bios); + wake_migration_worker(cache); + + background_work_end(cache); } -static void issue_discard(struct dm_cache_migration *mg) +static void mg_success(struct work_struct *ws) { - dm_dblock_t b, e; - struct bio *bio = mg->new_ocell->holder; - struct cache *cache = mg->cache; - - calc_discard_block_range(cache, bio, &b, &e); - while (b != e) { - set_discard(cache, b); - b = to_dblock(from_dblock(b) + 1); - } - - bio_endio(bio); - cell_defer(cache, mg->new_ocell, false); - free_migration(mg); - wake_worker(cache); + struct dm_cache_migration *mg = ws_to_mg(ws); + mg_complete(mg, mg->k.input == 0); } -static void issue_copy_or_discard(struct dm_cache_migration *mg) +static void mg_update_metadata(struct work_struct *ws) { - bool avoid; + int r; + struct dm_cache_migration *mg = ws_to_mg(ws); struct cache *cache = mg->cache; + struct policy_work *op = mg->op; - if (mg->discard) { - issue_discard(mg); - return; - } + switch (op->op) { + case POLICY_PROMOTE: + r = dm_cache_insert_mapping(cache->cmd, op->cblock, op->oblock); + if (r) { + DMERR_LIMIT("%s: migration failed; couldn't insert mapping", + cache_device_name(cache)); + metadata_operation_failed(cache, "dm_cache_insert_mapping", r); - if (mg->writeback || mg->demote) - avoid = !is_dirty(cache, mg->cblock) || - is_discarded_oblock(cache, mg->old_oblock); - else { - struct bio *bio = mg->new_ocell->holder; + mg_complete(mg, false); + return; + } + mg_complete(mg, true); + break; - avoid = is_discarded_oblock(cache, mg->new_oblock); + case POLICY_DEMOTE: + r = dm_cache_remove_mapping(cache->cmd, op->cblock); + if (r) { + DMERR_LIMIT("%s: migration failed; couldn't update on disk metadata", + cache_device_name(cache)); + metadata_operation_failed(cache, "dm_cache_remove_mapping", r); - if (writeback_mode(&cache->features) && - !avoid && bio_writes_complete_block(cache, bio)) { - issue_overwrite(mg, bio); + mg_complete(mg, false); return; } - } - avoid ? avoid_copy(mg) : issue_copy(mg); + /* + * It would be nice if we only had to commit when a REQ_FLUSH + * comes through. But there's one scenario that we have to + * look out for: + * + * - vblock x in a cache block + * - domotion occurs + * - cache block gets reallocated and over written + * - crash + * + * When we recover, because there was no commit the cache will + * rollback to having the data for vblock x in the cache block. + * But the cache block has since been overwritten, so it'll end + * up pointing to data that was never in 'x' during the history + * of the device. + * + * To avoid this issue we require a commit as part of the + * demotion operation. + */ + init_continuation(&mg->k, mg_success); + continue_after_commit(&cache->committer, &mg->k); + schedule_commit(&cache->committer); + break; + + case POLICY_WRITEBACK: + mg_complete(mg, true); + break; + } } -static void complete_migration(struct dm_cache_migration *mg) +static void mg_update_metadata_after_copy(struct work_struct *ws) { - if (mg->err) - migration_failure(mg); + struct dm_cache_migration *mg = ws_to_mg(ws); + + /* + * Did the copy succeed? + */ + if (mg->k.input) + mg_complete(mg, false); else - migration_success_pre_commit(mg); + mg_update_metadata(ws); } -static void process_migrations(struct cache *cache, struct list_head *head, - void (*fn)(struct dm_cache_migration *)) +static void mg_upgrade_lock(struct work_struct *ws) { - unsigned long flags; - struct list_head list; - struct dm_cache_migration *mg, *tmp; + int r; + struct dm_cache_migration *mg = ws_to_mg(ws); - INIT_LIST_HEAD(&list); - spin_lock_irqsave(&cache->lock, flags); - list_splice_init(head, &list); - spin_unlock_irqrestore(&cache->lock, flags); + /* + * Did the copy succeed? + */ + if (mg->k.input) + mg_complete(mg, false); - list_for_each_entry_safe(mg, tmp, &list, list) - fn(mg); -} + else { + /* + * Now we want the lock to prevent both reads and writes. + */ + r = dm_cell_lock_promote_v2(mg->cache->prison, mg->cell, + READ_WRITE_LOCK_LEVEL); + if (r < 0) + mg_complete(mg, false); -static void __queue_quiesced_migration(struct dm_cache_migration *mg) -{ - list_add_tail(&mg->list, &mg->cache->quiesced_migrations); + else if (r) + quiesce(mg, mg_update_metadata); + + else + mg_update_metadata(ws); + } } -static void queue_quiesced_migration(struct dm_cache_migration *mg) +static void mg_copy(struct work_struct *ws) { - unsigned long flags; - struct cache *cache = mg->cache; + int r; + struct dm_cache_migration *mg = ws_to_mg(ws); - spin_lock_irqsave(&cache->lock, flags); - __queue_quiesced_migration(mg); - spin_unlock_irqrestore(&cache->lock, flags); + if (mg->overwrite_bio) { + /* + * It's safe to do this here, even though it's new data + * because all IO has been locked out of the block. + * + * mg_lock_writes() already took READ_WRITE_LOCK_LEVEL + * so _not_ using mg_upgrade_lock() as continutation. + */ + overwrite(mg, mg_update_metadata_after_copy); - wake_worker(cache); -} + } else { + struct cache *cache = mg->cache; + struct policy_work *op = mg->op; + bool is_policy_promote = (op->op == POLICY_PROMOTE); -static void queue_quiesced_migrations(struct cache *cache, struct list_head *work) -{ - unsigned long flags; - struct dm_cache_migration *mg, *tmp; + if ((!is_policy_promote && !is_dirty(cache, op->cblock)) || + is_discarded_oblock(cache, op->oblock)) { + mg_upgrade_lock(ws); + return; + } - spin_lock_irqsave(&cache->lock, flags); - list_for_each_entry_safe(mg, tmp, work, list) - __queue_quiesced_migration(mg); - spin_unlock_irqrestore(&cache->lock, flags); + init_continuation(&mg->k, mg_upgrade_lock); - wake_worker(cache); + r = copy(mg, is_policy_promote); + if (r) { + DMERR_LIMIT("%s: migration copy failed", cache_device_name(cache)); + mg->k.input = -EIO; + mg_complete(mg, false); + } + } } -static void check_for_quiesced_migrations(struct cache *cache, - struct per_bio_data *pb) +static int mg_lock_writes(struct dm_cache_migration *mg) { - struct list_head work; + int r; + struct dm_cell_key_v2 key; + struct cache *cache = mg->cache; + struct dm_bio_prison_cell_v2 *prealloc; - if (!pb->all_io_entry) - return; + prealloc = alloc_prison_cell(cache); + if (!prealloc) { + DMERR_LIMIT("%s: alloc_prison_cell failed", cache_device_name(cache)); + mg_complete(mg, false); + return -ENOMEM; + } + + /* + * Prevent writes to the block, but allow reads to continue. + * Unless we're using an overwrite bio, in which case we lock + * everything. + */ + build_key(mg->op->oblock, oblock_succ(mg->op->oblock), &key); + r = dm_cell_lock_v2(cache->prison, &key, + mg->overwrite_bio ? READ_WRITE_LOCK_LEVEL : WRITE_LOCK_LEVEL, + prealloc, &mg->cell); + if (r < 0) { + free_prison_cell(cache, prealloc); + mg_complete(mg, false); + return r; + } - INIT_LIST_HEAD(&work); - dm_deferred_entry_dec(pb->all_io_entry, &work); + if (mg->cell != prealloc) + free_prison_cell(cache, prealloc); - if (!list_empty(&work)) - queue_quiesced_migrations(cache, &work); -} + if (r == 0) + mg_copy(&mg->k.ws); + else + quiesce(mg, mg_copy); -static void quiesce_migration(struct dm_cache_migration *mg) -{ - if (!dm_deferred_set_add_work(mg->cache->all_io_ds, &mg->list)) - queue_quiesced_migration(mg); + return 0; } -static void promote(struct cache *cache, struct prealloc *structs, - dm_oblock_t oblock, dm_cblock_t cblock, - struct dm_bio_prison_cell *cell) +static int mg_start(struct cache *cache, struct policy_work *op, struct bio *bio) { - struct dm_cache_migration *mg = prealloc_get_migration(structs); + struct dm_cache_migration *mg; + + if (!background_work_begin(cache)) { + policy_complete_background_work(cache->policy, op, false); + return -EPERM; + } + + mg = alloc_migration(cache); + if (!mg) { + policy_complete_background_work(cache->policy, op, false); + background_work_end(cache); + return -ENOMEM; + } + + memset(mg, 0, sizeof(*mg)); - mg->err = false; - mg->discard = false; - mg->writeback = false; - mg->demote = false; - mg->promote = true; - mg->requeue_holder = true; - mg->invalidate = false; mg->cache = cache; - mg->new_oblock = oblock; - mg->cblock = cblock; - mg->old_ocell = NULL; - mg->new_ocell = cell; - mg->start_jiffies = jiffies; + mg->op = op; + mg->overwrite_bio = bio; - inc_io_migrations(cache); - quiesce_migration(mg); + if (!bio) + inc_io_migrations(cache); + + return mg_lock_writes(mg); } -static void writeback(struct cache *cache, struct prealloc *structs, - dm_oblock_t oblock, dm_cblock_t cblock, - struct dm_bio_prison_cell *cell) +/*---------------------------------------------------------------- + * invalidation processing + *--------------------------------------------------------------*/ + +static void invalidate_complete(struct dm_cache_migration *mg, bool success) { - struct dm_cache_migration *mg = prealloc_get_migration(structs); + struct bio_list bios; + struct cache *cache = mg->cache; - mg->err = false; - mg->discard = false; - mg->writeback = true; - mg->demote = false; - mg->promote = false; - mg->requeue_holder = true; - mg->invalidate = false; - mg->cache = cache; - mg->old_oblock = oblock; - mg->cblock = cblock; - mg->old_ocell = cell; - mg->new_ocell = NULL; - mg->start_jiffies = jiffies; - - inc_io_migrations(cache); - quiesce_migration(mg); -} - -static void demote_then_promote(struct cache *cache, struct prealloc *structs, - dm_oblock_t old_oblock, dm_oblock_t new_oblock, - dm_cblock_t cblock, - struct dm_bio_prison_cell *old_ocell, - struct dm_bio_prison_cell *new_ocell) -{ - struct dm_cache_migration *mg = prealloc_get_migration(structs); - - mg->err = false; - mg->discard = false; - mg->writeback = false; - mg->demote = true; - mg->promote = true; - mg->requeue_holder = true; - mg->invalidate = false; - mg->cache = cache; - mg->old_oblock = old_oblock; - mg->new_oblock = new_oblock; - mg->cblock = cblock; - mg->old_ocell = old_ocell; - mg->new_ocell = new_ocell; - mg->start_jiffies = jiffies; + bio_list_init(&bios); + if (dm_cell_unlock_v2(cache->prison, mg->cell, &bios)) + free_prison_cell(cache, mg->cell); - inc_io_migrations(cache); - quiesce_migration(mg); -} + if (!success && mg->overwrite_bio) + bio_io_error(mg->overwrite_bio); -/* - * Invalidate a cache entry. No writeback occurs; any changes in the cache - * block are thrown away. - */ -static void invalidate(struct cache *cache, struct prealloc *structs, - dm_oblock_t oblock, dm_cblock_t cblock, - struct dm_bio_prison_cell *cell) -{ - struct dm_cache_migration *mg = prealloc_get_migration(structs); - - mg->err = false; - mg->discard = false; - mg->writeback = false; - mg->demote = true; - mg->promote = false; - mg->requeue_holder = true; - mg->invalidate = true; - mg->cache = cache; - mg->old_oblock = oblock; - mg->cblock = cblock; - mg->old_ocell = cell; - mg->new_ocell = NULL; - mg->start_jiffies = jiffies; + free_migration(mg); + defer_bios(cache, &bios); - inc_io_migrations(cache); - quiesce_migration(mg); + background_work_end(cache); } -static void discard(struct cache *cache, struct prealloc *structs, - struct dm_bio_prison_cell *cell) +static void invalidate_completed(struct work_struct *ws) { - struct dm_cache_migration *mg = prealloc_get_migration(structs); + struct dm_cache_migration *mg = ws_to_mg(ws); + invalidate_complete(mg, !mg->k.input); +} - mg->err = false; - mg->discard = true; - mg->writeback = false; - mg->demote = false; - mg->promote = false; - mg->requeue_holder = false; - mg->invalidate = false; - mg->cache = cache; - mg->old_ocell = NULL; - mg->new_ocell = cell; - mg->start_jiffies = jiffies; +static int invalidate_cblock(struct cache *cache, dm_cblock_t cblock) +{ + int r = policy_invalidate_mapping(cache->policy, cblock); + if (!r) { + r = dm_cache_remove_mapping(cache->cmd, cblock); + if (r) { + DMERR_LIMIT("%s: invalidation failed; couldn't update on disk metadata", + cache_device_name(cache)); + metadata_operation_failed(cache, "dm_cache_remove_mapping", r); + } + + } else if (r == -ENODATA) { + /* + * Harmless, already unmapped. + */ + r = 0; + + } else + DMERR("%s: policy_invalidate_mapping failed", cache_device_name(cache)); - quiesce_migration(mg); + return r; } -/*---------------------------------------------------------------- - * bio processing - *--------------------------------------------------------------*/ -static void defer_bio(struct cache *cache, struct bio *bio) +static void invalidate_remove(struct work_struct *ws) { - unsigned long flags; + int r; + struct dm_cache_migration *mg = ws_to_mg(ws); + struct cache *cache = mg->cache; - spin_lock_irqsave(&cache->lock, flags); - bio_list_add(&cache->deferred_bios, bio); - spin_unlock_irqrestore(&cache->lock, flags); + r = invalidate_cblock(cache, mg->invalidate_cblock); + if (r) { + invalidate_complete(mg, false); + return; + } - wake_worker(cache); + init_continuation(&mg->k, invalidate_completed); + continue_after_commit(&cache->committer, &mg->k); + remap_to_origin_clear_discard(cache, mg->overwrite_bio, mg->invalidate_oblock); + mg->overwrite_bio = NULL; + schedule_commit(&cache->committer); } -static void process_flush_bio(struct cache *cache, struct bio *bio) +static int invalidate_lock(struct dm_cache_migration *mg) { - size_t pb_data_size = get_per_bio_data_size(cache); - struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); + int r; + struct dm_cell_key_v2 key; + struct cache *cache = mg->cache; + struct dm_bio_prison_cell_v2 *prealloc; - BUG_ON(bio->bi_iter.bi_size); - if (!pb->req_nr) - remap_to_origin(cache, bio); - else - remap_to_cache(cache, bio, 0); + prealloc = alloc_prison_cell(cache); + if (!prealloc) { + invalidate_complete(mg, false); + return -ENOMEM; + } - /* - * REQ_PREFLUSH is not directed at any particular block so we don't - * need to inc_ds(). REQ_FUA's are split into a write + REQ_PREFLUSH - * by dm-core. - */ - issue(cache, bio); + build_key(mg->invalidate_oblock, oblock_succ(mg->invalidate_oblock), &key); + r = dm_cell_lock_v2(cache->prison, &key, + READ_WRITE_LOCK_LEVEL, prealloc, &mg->cell); + if (r < 0) { + free_prison_cell(cache, prealloc); + invalidate_complete(mg, false); + return r; + } + + if (mg->cell != prealloc) + free_prison_cell(cache, prealloc); + + if (r) + quiesce(mg, invalidate_remove); + + else { + /* + * We can't call invalidate_remove() directly here because we + * might still be in request context. + */ + init_continuation(&mg->k, invalidate_remove); + queue_work(cache->wq, &mg->k.ws); + } + + return 0; } -static void process_discard_bio(struct cache *cache, struct prealloc *structs, - struct bio *bio) +static int invalidate_start(struct cache *cache, dm_cblock_t cblock, + dm_oblock_t oblock, struct bio *bio) { - int r; - dm_dblock_t b, e; - struct dm_bio_prison_cell *cell_prealloc, *new_ocell; + struct dm_cache_migration *mg; - calc_discard_block_range(cache, bio, &b, &e); - if (b == e) { - bio_endio(bio); - return; + if (!background_work_begin(cache)) + return -EPERM; + + mg = alloc_migration(cache); + if (!mg) { + background_work_end(cache); + return -ENOMEM; } - cell_prealloc = prealloc_get_cell(structs); - r = bio_detain_range(cache, dblock_to_oblock(cache, b), dblock_to_oblock(cache, e), bio, cell_prealloc, - (cell_free_fn) prealloc_put_cell, - structs, &new_ocell); - if (r > 0) - return; + memset(mg, 0, sizeof(*mg)); - discard(cache, structs, new_ocell); + mg->cache = cache; + mg->overwrite_bio = bio; + mg->invalidate_cblock = cblock; + mg->invalidate_oblock = oblock; + + return invalidate_lock(mg); } -static bool spare_migration_bandwidth(struct cache *cache) +/*---------------------------------------------------------------- + * bio processing + *--------------------------------------------------------------*/ + +enum busy { + IDLE, + MODERATE, + BUSY +}; + +static enum busy spare_migration_bandwidth(struct cache *cache) { + bool idle = iot_idle_for(&cache->origin_tracker, HZ); sector_t current_volume = (atomic_read(&cache->nr_io_migrations) + 1) * cache->sectors_per_block; - return current_volume < cache->migration_threshold; + + if (current_volume <= cache->migration_threshold) + return idle ? IDLE : MODERATE; + else + return idle ? MODERATE : BUSY; } static void inc_hit_counter(struct cache *cache, struct bio *bio) @@ -1660,255 +1746,143 @@ static void inc_miss_counter(struct cache *cache, struct bio *bio) /*----------------------------------------------------------------*/ -struct inc_detail { - struct cache *cache; - struct bio_list bios_for_issue; - struct bio_list unhandled_bios; - bool any_writes; -}; - -static void inc_fn(void *context, struct dm_bio_prison_cell *cell) +static bool bio_writes_complete_block(struct cache *cache, struct bio *bio) { - struct bio *bio; - struct inc_detail *detail = context; - struct cache *cache = detail->cache; - - inc_ds(cache, cell->holder, cell); - if (bio_data_dir(cell->holder) == WRITE) - detail->any_writes = true; - - while ((bio = bio_list_pop(&cell->bios))) { - if (discard_or_flush(bio)) { - bio_list_add(&detail->unhandled_bios, bio); - continue; - } - - if (bio_data_dir(bio) == WRITE) - detail->any_writes = true; - - bio_list_add(&detail->bios_for_issue, bio); - inc_ds(cache, bio, cell); - } + return (bio_data_dir(bio) == WRITE) && + (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT)); } -// FIXME: refactor these two -static void remap_cell_to_origin_clear_discard(struct cache *cache, - struct dm_bio_prison_cell *cell, - dm_oblock_t oblock, bool issue_holder) +static bool optimisable_bio(struct cache *cache, struct bio *bio, dm_oblock_t block) { - struct bio *bio; - unsigned long flags; - struct inc_detail detail; - - detail.cache = cache; - bio_list_init(&detail.bios_for_issue); - bio_list_init(&detail.unhandled_bios); - detail.any_writes = false; - - spin_lock_irqsave(&cache->lock, flags); - dm_cell_visit_release(cache->prison, inc_fn, &detail, cell); - bio_list_merge(&cache->deferred_bios, &detail.unhandled_bios); - spin_unlock_irqrestore(&cache->lock, flags); - - remap_to_origin(cache, cell->holder); - if (issue_holder) - issue(cache, cell->holder); - else - accounted_begin(cache, cell->holder); - - if (detail.any_writes) - clear_discard(cache, oblock_to_dblock(cache, oblock)); - - while ((bio = bio_list_pop(&detail.bios_for_issue))) { - remap_to_origin(cache, bio); - issue(cache, bio); - } - - free_prison_cell(cache, cell); + return writeback_mode(&cache->features) && + (is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio)); } -static void remap_cell_to_cache_dirty(struct cache *cache, struct dm_bio_prison_cell *cell, - dm_oblock_t oblock, dm_cblock_t cblock, bool issue_holder) +static int map_bio(struct cache *cache, struct bio *bio, dm_oblock_t block, + bool *commit_needed) { - struct bio *bio; - unsigned long flags; - struct inc_detail detail; - - detail.cache = cache; - bio_list_init(&detail.bios_for_issue); - bio_list_init(&detail.unhandled_bios); - detail.any_writes = false; - - spin_lock_irqsave(&cache->lock, flags); - dm_cell_visit_release(cache->prison, inc_fn, &detail, cell); - bio_list_merge(&cache->deferred_bios, &detail.unhandled_bios); - spin_unlock_irqrestore(&cache->lock, flags); + int r, data_dir; + bool rb, background_queued; + dm_cblock_t cblock; + size_t pb_data_size = get_per_bio_data_size(cache); + struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); - remap_to_cache(cache, cell->holder, cblock); - if (issue_holder) - issue(cache, cell->holder); - else - accounted_begin(cache, cell->holder); + *commit_needed = false; - if (detail.any_writes) { - set_dirty(cache, oblock, cblock); - clear_discard(cache, oblock_to_dblock(cache, oblock)); - } - - while ((bio = bio_list_pop(&detail.bios_for_issue))) { - remap_to_cache(cache, bio, cblock); - issue(cache, bio); + rb = bio_detain_shared(cache, block, bio); + if (!rb) { + /* + * An exclusive lock is held for this block, so we have to + * wait. We set the commit_needed flag so the current + * transaction will be committed asap, allowing this lock + * to be dropped. + */ + *commit_needed = true; + return DM_MAPIO_SUBMITTED; } - free_prison_cell(cache, cell); -} + data_dir = bio_data_dir(bio); -/*----------------------------------------------------------------*/ - -struct old_oblock_lock { - struct policy_locker locker; - struct cache *cache; - struct prealloc *structs; - struct dm_bio_prison_cell *cell; -}; + if (optimisable_bio(cache, bio, block)) { + struct policy_work *op = NULL; -static int null_locker(struct policy_locker *locker, dm_oblock_t b) -{ - /* This should never be called */ - BUG(); - return 0; -} + r = policy_lookup_with_work(cache->policy, block, &cblock, data_dir, true, &op); + if (unlikely(r && r != -ENOENT)) { + DMERR_LIMIT("%s: policy_lookup_with_work() failed with r = %d", + cache_device_name(cache), r); + bio_io_error(bio); + return DM_MAPIO_SUBMITTED; + } -static int cell_locker(struct policy_locker *locker, dm_oblock_t b) -{ - struct old_oblock_lock *l = container_of(locker, struct old_oblock_lock, locker); - struct dm_bio_prison_cell *cell_prealloc = prealloc_get_cell(l->structs); + if (r == -ENOENT && op) { + bio_drop_shared_lock(cache, bio); + BUG_ON(op->op != POLICY_PROMOTE); + mg_start(cache, op, bio); + return DM_MAPIO_SUBMITTED; + } + } else { + r = policy_lookup(cache->policy, block, &cblock, data_dir, false, &background_queued); + if (unlikely(r && r != -ENOENT)) { + DMERR_LIMIT("%s: policy_lookup() failed with r = %d", + cache_device_name(cache), r); + bio_io_error(bio); + return DM_MAPIO_SUBMITTED; + } - return bio_detain(l->cache, b, NULL, cell_prealloc, - (cell_free_fn) prealloc_put_cell, - l->structs, &l->cell); -} + if (background_queued) + wake_migration_worker(cache); + } -static void process_cell(struct cache *cache, struct prealloc *structs, - struct dm_bio_prison_cell *new_ocell) -{ - int r; - bool release_cell = true; - struct bio *bio = new_ocell->holder; - dm_oblock_t block = get_bio_block(cache, bio); - struct policy_result lookup_result; - bool passthrough = passthrough_mode(&cache->features); - bool fast_promotion, can_migrate; - struct old_oblock_lock ool; - - fast_promotion = is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio); - can_migrate = !passthrough && (fast_promotion || spare_migration_bandwidth(cache)); - - ool.locker.fn = cell_locker; - ool.cache = cache; - ool.structs = structs; - ool.cell = NULL; - r = policy_map(cache->policy, block, true, can_migrate, fast_promotion, - bio, &ool.locker, &lookup_result); - - if (r == -EWOULDBLOCK) - /* migration has been denied */ - lookup_result.op = POLICY_MISS; - - switch (lookup_result.op) { - case POLICY_HIT: - if (passthrough) { - inc_miss_counter(cache, bio); + if (r == -ENOENT) { + /* + * Miss. + */ + inc_miss_counter(cache, bio); + if (pb->req_nr == 0) { + accounted_begin(cache, bio); + remap_to_origin_clear_discard(cache, bio, block); + } else { /* - * Passthrough always maps to the origin, - * invalidating any cache blocks that are written - * to. + * This is a duplicate writethrough io that is no + * longer needed because the block has been demoted. */ + bio_endio(bio); + return DM_MAPIO_SUBMITTED; + } + } else { + /* + * Hit. + */ + inc_hit_counter(cache, bio); + /* + * Passthrough always maps to the origin, invalidating any + * cache blocks that are written to. + */ + if (passthrough_mode(&cache->features)) { if (bio_data_dir(bio) == WRITE) { + bio_drop_shared_lock(cache, bio); atomic_inc(&cache->stats.demotion); - invalidate(cache, structs, block, lookup_result.cblock, new_ocell); - release_cell = false; - - } else { - /* FIXME: factor out issue_origin() */ + invalidate_start(cache, cblock, block, bio); + } else remap_to_origin_clear_discard(cache, bio, block); - inc_and_issue(cache, bio, new_ocell); - } + } else { - inc_hit_counter(cache, bio); - - if (bio_data_dir(bio) == WRITE && - writethrough_mode(&cache->features) && - !is_dirty(cache, lookup_result.cblock)) { - remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); - inc_and_issue(cache, bio, new_ocell); - - } else { - remap_cell_to_cache_dirty(cache, new_ocell, block, lookup_result.cblock, true); - release_cell = false; - } + if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) && + !is_dirty(cache, cblock)) { + remap_to_origin_then_cache(cache, bio, block, cblock); + accounted_begin(cache, bio); + } else + remap_to_cache_dirty(cache, bio, block, cblock); } - - break; - - case POLICY_MISS: - inc_miss_counter(cache, bio); - remap_cell_to_origin_clear_discard(cache, new_ocell, block, true); - release_cell = false; - break; - - case POLICY_NEW: - atomic_inc(&cache->stats.promotion); - promote(cache, structs, block, lookup_result.cblock, new_ocell); - release_cell = false; - break; - - case POLICY_REPLACE: - atomic_inc(&cache->stats.demotion); - atomic_inc(&cache->stats.promotion); - demote_then_promote(cache, structs, lookup_result.old_oblock, - block, lookup_result.cblock, - ool.cell, new_ocell); - release_cell = false; - break; - - default: - DMERR_LIMIT("%s: %s: erroring bio, unknown policy op: %u", - cache_device_name(cache), __func__, - (unsigned) lookup_result.op); - bio_io_error(bio); } - if (release_cell) - cell_defer(cache, new_ocell, false); -} - -static void process_bio(struct cache *cache, struct prealloc *structs, - struct bio *bio) -{ - int r; - dm_oblock_t block = get_bio_block(cache, bio); - struct dm_bio_prison_cell *cell_prealloc, *new_ocell; - /* - * Check to see if that block is currently migrating. + * dm core turns FUA requests into a separate payload and FLUSH req. */ - cell_prealloc = prealloc_get_cell(structs); - r = bio_detain(cache, block, bio, cell_prealloc, - (cell_free_fn) prealloc_put_cell, - structs, &new_ocell); - if (r > 0) - return; + if (bio->bi_opf & REQ_FUA) { + /* + * issue_after_commit will call accounted_begin a second time. So + * we call accounted_complete() to avoid double accounting. + */ + accounted_complete(cache, bio); + issue_after_commit(&cache->committer, bio); + *commit_needed = true; + return DM_MAPIO_SUBMITTED; + } - process_cell(cache, structs, new_ocell); + return DM_MAPIO_REMAPPED; } -static int need_commit_due_to_time(struct cache *cache) +static bool process_bio(struct cache *cache, struct bio *bio) { - return jiffies < cache->last_commit_jiffies || - jiffies > cache->last_commit_jiffies + COMMIT_PERIOD; + bool commit_needed; + + if (map_bio(cache, bio, get_bio_block(cache, bio), &commit_needed) == DM_MAPIO_REMAPPED) + generic_make_request(bio); + + return commit_needed; } /* @@ -1929,123 +1903,88 @@ static int commit(struct cache *cache, bool clean_shutdown) return r; } -static int commit_if_needed(struct cache *cache) +/* + * Used by the batcher. + */ +static int commit_op(void *context) { - int r = 0; + struct cache *cache = context; - if ((cache->commit_requested || need_commit_due_to_time(cache)) && - dm_cache_changed_this_transaction(cache->cmd)) { - r = commit(cache, false); - cache->commit_requested = false; - cache->last_commit_jiffies = jiffies; - } + if (dm_cache_changed_this_transaction(cache->cmd)) + return commit(cache, false); - return r; + return 0; } -static void process_deferred_bios(struct cache *cache) -{ - bool prealloc_used = false; - unsigned long flags; - struct bio_list bios; - struct bio *bio; - struct prealloc structs; - - memset(&structs, 0, sizeof(structs)); - bio_list_init(&bios); - - spin_lock_irqsave(&cache->lock, flags); - bio_list_merge(&bios, &cache->deferred_bios); - bio_list_init(&cache->deferred_bios); - spin_unlock_irqrestore(&cache->lock, flags); - - while (!bio_list_empty(&bios)) { - /* - * If we've got no free migration structs, and processing - * this bio might require one, we pause until there are some - * prepared mappings to process. - */ - prealloc_used = true; - if (prealloc_data_structs(cache, &structs)) { - spin_lock_irqsave(&cache->lock, flags); - bio_list_merge(&cache->deferred_bios, &bios); - spin_unlock_irqrestore(&cache->lock, flags); - break; - } +/*----------------------------------------------------------------*/ - bio = bio_list_pop(&bios); +static bool process_flush_bio(struct cache *cache, struct bio *bio) +{ + size_t pb_data_size = get_per_bio_data_size(cache); + struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); - if (bio->bi_opf & REQ_PREFLUSH) - process_flush_bio(cache, bio); - else if (bio_op(bio) == REQ_OP_DISCARD) - process_discard_bio(cache, &structs, bio); - else - process_bio(cache, &structs, bio); - } + if (!pb->req_nr) + remap_to_origin(cache, bio); + else + remap_to_cache(cache, bio, 0); - if (prealloc_used) - prealloc_free_structs(cache, &structs); + issue_after_commit(&cache->committer, bio); + return true; } -static void process_deferred_cells(struct cache *cache) +static bool process_discard_bio(struct cache *cache, struct bio *bio) { - bool prealloc_used = false; - unsigned long flags; - struct dm_bio_prison_cell *cell, *tmp; - struct list_head cells; - struct prealloc structs; - - memset(&structs, 0, sizeof(structs)); - - INIT_LIST_HEAD(&cells); - - spin_lock_irqsave(&cache->lock, flags); - list_splice_init(&cache->deferred_cells, &cells); - spin_unlock_irqrestore(&cache->lock, flags); - - list_for_each_entry_safe(cell, tmp, &cells, user_list) { - /* - * If we've got no free migration structs, and processing - * this bio might require one, we pause until there are some - * prepared mappings to process. - */ - prealloc_used = true; - if (prealloc_data_structs(cache, &structs)) { - spin_lock_irqsave(&cache->lock, flags); - list_splice(&cells, &cache->deferred_cells); - spin_unlock_irqrestore(&cache->lock, flags); - break; - } + dm_dblock_t b, e; - process_cell(cache, &structs, cell); + // FIXME: do we need to lock the region? Or can we just assume the + // user wont be so foolish as to issue discard concurrently with + // other IO? + calc_discard_block_range(cache, bio, &b, &e); + while (b != e) { + set_discard(cache, b); + b = to_dblock(from_dblock(b) + 1); } - if (prealloc_used) - prealloc_free_structs(cache, &structs); + bio_endio(bio); + + return false; } -static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) +static void process_deferred_bios(struct work_struct *ws) { + struct cache *cache = container_of(ws, struct cache, deferred_bio_worker); + unsigned long flags; + bool commit_needed = false; struct bio_list bios; struct bio *bio; bio_list_init(&bios); spin_lock_irqsave(&cache->lock, flags); - bio_list_merge(&bios, &cache->deferred_flush_bios); - bio_list_init(&cache->deferred_flush_bios); + bio_list_merge(&bios, &cache->deferred_bios); + bio_list_init(&cache->deferred_bios); spin_unlock_irqrestore(&cache->lock, flags); - /* - * These bios have already been through inc_ds() - */ - while ((bio = bio_list_pop(&bios))) - submit_bios ? accounted_request(cache, bio) : bio_io_error(bio); + while ((bio = bio_list_pop(&bios))) { + if (bio->bi_opf & REQ_PREFLUSH) + commit_needed = process_flush_bio(cache, bio) || commit_needed; + + else if (bio_op(bio) == REQ_OP_DISCARD) + commit_needed = process_discard_bio(cache, bio) || commit_needed; + + else + commit_needed = process_bio(cache, bio) || commit_needed; + } + + if (commit_needed) + schedule_commit(&cache->committer); } -static void process_deferred_writethrough_bios(struct cache *cache) +static void process_deferred_writethrough_bios(struct work_struct *ws) { + struct cache *cache = container_of(ws, struct cache, deferred_writethrough_worker); + unsigned long flags; struct bio_list bios; struct bio *bio; @@ -2058,153 +1997,15 @@ static void process_deferred_writethrough_bios(struct cache *cache) spin_unlock_irqrestore(&cache->lock, flags); /* - * These bios have already been through inc_ds() + * These bios have already been through accounted_begin() */ while ((bio = bio_list_pop(&bios))) - accounted_request(cache, bio); -} - -static void writeback_some_dirty_blocks(struct cache *cache) -{ - bool prealloc_used = false; - dm_oblock_t oblock; - dm_cblock_t cblock; - struct prealloc structs; - struct dm_bio_prison_cell *old_ocell; - bool busy = !iot_idle_for(&cache->origin_tracker, HZ); - - memset(&structs, 0, sizeof(structs)); - - while (spare_migration_bandwidth(cache)) { - if (policy_writeback_work(cache->policy, &oblock, &cblock, busy)) - break; /* no work to do */ - - prealloc_used = true; - if (prealloc_data_structs(cache, &structs) || - get_cell(cache, oblock, &structs, &old_ocell)) { - policy_set_dirty(cache->policy, oblock); - break; - } - - writeback(cache, &structs, oblock, cblock, old_ocell); - } - - if (prealloc_used) - prealloc_free_structs(cache, &structs); -} - -/*---------------------------------------------------------------- - * Invalidations. - * Dropping something from the cache *without* writing back. - *--------------------------------------------------------------*/ - -static void process_invalidation_request(struct cache *cache, struct invalidation_request *req) -{ - int r = 0; - uint64_t begin = from_cblock(req->cblocks->begin); - uint64_t end = from_cblock(req->cblocks->end); - - while (begin != end) { - r = policy_remove_cblock(cache->policy, to_cblock(begin)); - if (!r) { - r = dm_cache_remove_mapping(cache->cmd, to_cblock(begin)); - if (r) { - metadata_operation_failed(cache, "dm_cache_remove_mapping", r); - break; - } - - } else if (r == -ENODATA) { - /* harmless, already unmapped */ - r = 0; - - } else { - DMERR("%s: policy_remove_cblock failed", cache_device_name(cache)); - break; - } - - begin++; - } - - cache->commit_requested = true; - - req->err = r; - atomic_set(&req->complete, 1); - - wake_up(&req->result_wait); -} - -static void process_invalidation_requests(struct cache *cache) -{ - struct list_head list; - struct invalidation_request *req, *tmp; - - INIT_LIST_HEAD(&list); - spin_lock(&cache->invalidation_lock); - list_splice_init(&cache->invalidation_requests, &list); - spin_unlock(&cache->invalidation_lock); - - list_for_each_entry_safe (req, tmp, &list, list) - process_invalidation_request(cache, req); + generic_make_request(bio); } /*---------------------------------------------------------------- * Main worker loop *--------------------------------------------------------------*/ -static bool is_quiescing(struct cache *cache) -{ - return atomic_read(&cache->quiescing); -} - -static void ack_quiescing(struct cache *cache) -{ - if (is_quiescing(cache)) { - atomic_inc(&cache->quiescing_ack); - wake_up(&cache->quiescing_wait); - } -} - -static void wait_for_quiescing_ack(struct cache *cache) -{ - wait_event(cache->quiescing_wait, atomic_read(&cache->quiescing_ack)); -} - -static void start_quiescing(struct cache *cache) -{ - atomic_inc(&cache->quiescing); - wait_for_quiescing_ack(cache); -} - -static void stop_quiescing(struct cache *cache) -{ - atomic_set(&cache->quiescing, 0); - atomic_set(&cache->quiescing_ack, 0); -} - -static void wait_for_migrations(struct cache *cache) -{ - wait_event(cache->migration_wait, !atomic_read(&cache->nr_allocated_migrations)); -} - -static void stop_worker(struct cache *cache) -{ - cancel_delayed_work(&cache->waker); - flush_workqueue(cache->wq); -} - -static void requeue_deferred_cells(struct cache *cache) -{ - unsigned long flags; - struct list_head cells; - struct dm_bio_prison_cell *cell, *tmp; - - INIT_LIST_HEAD(&cells); - spin_lock_irqsave(&cache->lock, flags); - list_splice_init(&cache->deferred_cells, &cells); - spin_unlock_irqrestore(&cache->lock, flags); - - list_for_each_entry_safe(cell, tmp, &cells, user_list) - cell_requeue(cache, cell); -} static void requeue_deferred_bios(struct cache *cache) { @@ -2221,53 +2022,6 @@ static void requeue_deferred_bios(struct cache *cache) } } -static int more_work(struct cache *cache) -{ - if (is_quiescing(cache)) - return !list_empty(&cache->quiesced_migrations) || - !list_empty(&cache->completed_migrations) || - !list_empty(&cache->need_commit_migrations); - else - return !bio_list_empty(&cache->deferred_bios) || - !list_empty(&cache->deferred_cells) || - !bio_list_empty(&cache->deferred_flush_bios) || - !bio_list_empty(&cache->deferred_writethrough_bios) || - !list_empty(&cache->quiesced_migrations) || - !list_empty(&cache->completed_migrations) || - !list_empty(&cache->need_commit_migrations) || - cache->invalidate; -} - -static void do_worker(struct work_struct *ws) -{ - struct cache *cache = container_of(ws, struct cache, worker); - - do { - if (!is_quiescing(cache)) { - writeback_some_dirty_blocks(cache); - process_deferred_writethrough_bios(cache); - process_deferred_bios(cache); - process_deferred_cells(cache); - process_invalidation_requests(cache); - } - - process_migrations(cache, &cache->quiesced_migrations, issue_copy_or_discard); - process_migrations(cache, &cache->completed_migrations, complete_migration); - - if (commit_if_needed(cache)) { - process_deferred_flush_bios(cache, false); - process_migrations(cache, &cache->need_commit_migrations, migration_failure); - } else { - process_deferred_flush_bios(cache, true); - process_migrations(cache, &cache->need_commit_migrations, - migration_success_post_commit); - } - - ack_quiescing(cache); - - } while (more_work(cache)); -} - /* * We want to commit periodically so that not too much * unwritten metadata builds up. @@ -2275,25 +2029,39 @@ static void do_worker(struct work_struct *ws) static void do_waker(struct work_struct *ws) { struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker); + policy_tick(cache->policy, true); - wake_worker(cache); + wake_migration_worker(cache); + schedule_commit(&cache->committer); queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); } -/*----------------------------------------------------------------*/ - -static int is_congested(struct dm_dev *dev, int bdi_bits) +static void check_migrations(struct work_struct *ws) { - struct request_queue *q = bdev_get_queue(dev->bdev); - return bdi_congested(q->backing_dev_info, bdi_bits); -} + int r; + struct policy_work *op; + struct cache *cache = container_of(ws, struct cache, migration_worker); + enum busy b; -static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits) -{ - struct cache *cache = container_of(cb, struct cache, callbacks); + for (;;) { + b = spare_migration_bandwidth(cache); + if (b == BUSY) + break; - return is_congested(cache->origin_dev, bdi_bits) || - is_congested(cache->cache_dev, bdi_bits); + r = policy_get_background_work(cache->policy, b == IDLE, &op); + if (r == -ENODATA) + break; + + if (r) { + DMERR_LIMIT("%s: policy_background_work failed", + cache_device_name(cache)); + break; + } + + r = mg_start(cache, op, NULL); + if (r) + break; + } } /*---------------------------------------------------------------- @@ -2310,11 +2078,8 @@ static void destroy(struct cache *cache) mempool_destroy(cache->migration_pool); - if (cache->all_io_ds) - dm_deferred_set_destroy(cache->all_io_ds); - if (cache->prison) - dm_bio_prison_destroy(cache->prison); + dm_bio_prison_destroy_v2(cache->prison); if (cache->wq) destroy_workqueue(cache->wq); @@ -2707,6 +2472,7 @@ static int create_cache_policy(struct cache *cache, struct cache_args *ca, return PTR_ERR(p); } cache->policy = p; + BUG_ON(!cache->policy); return 0; } @@ -2750,6 +2516,20 @@ static void set_cache_size(struct cache *cache, dm_cblock_t size) cache->cache_size = size; } +static int is_congested(struct dm_dev *dev, int bdi_bits) +{ + struct request_queue *q = bdev_get_queue(dev->bdev); + return bdi_congested(q->backing_dev_info, bdi_bits); +} + +static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits) +{ + struct cache *cache = container_of(cb, struct cache, callbacks); + + return is_congested(cache->origin_dev, bdi_bits) || + is_congested(cache->cache_dev, bdi_bits); +} + #define DEFAULT_MIGRATION_THRESHOLD 2048 static int cache_create(struct cache_args *ca, struct cache **result) @@ -2788,7 +2568,6 @@ static int cache_create(struct cache_args *ca, struct cache **result) ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; - /* FIXME: factor out this whole section */ origin_blocks = cache->origin_sectors = ca->origin_sectors; origin_blocks = block_div(origin_blocks, ca->block_size); cache->origin_blocks = to_oblock(origin_blocks); @@ -2854,24 +2633,18 @@ static int cache_create(struct cache_args *ca, struct cache **result) r = -EINVAL; goto bad; } + + policy_allow_migrations(cache->policy, false); } spin_lock_init(&cache->lock); INIT_LIST_HEAD(&cache->deferred_cells); bio_list_init(&cache->deferred_bios); - bio_list_init(&cache->deferred_flush_bios); bio_list_init(&cache->deferred_writethrough_bios); - INIT_LIST_HEAD(&cache->quiesced_migrations); - INIT_LIST_HEAD(&cache->completed_migrations); - INIT_LIST_HEAD(&cache->need_commit_migrations); atomic_set(&cache->nr_allocated_migrations, 0); atomic_set(&cache->nr_io_migrations, 0); init_waitqueue_head(&cache->migration_wait); - init_waitqueue_head(&cache->quiescing_wait); - atomic_set(&cache->quiescing, 0); - atomic_set(&cache->quiescing_ack, 0); - r = -ENOMEM; atomic_set(&cache->nr_dirty, 0); cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size)); @@ -2900,27 +2673,23 @@ static int cache_create(struct cache_args *ca, struct cache **result) goto bad; } - cache->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); + cache->wq = alloc_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM, 0); if (!cache->wq) { *error = "could not create workqueue for metadata object"; goto bad; } - INIT_WORK(&cache->worker, do_worker); + INIT_WORK(&cache->deferred_bio_worker, process_deferred_bios); + INIT_WORK(&cache->deferred_writethrough_worker, + process_deferred_writethrough_bios); + INIT_WORK(&cache->migration_worker, check_migrations); INIT_DELAYED_WORK(&cache->waker, do_waker); - cache->last_commit_jiffies = jiffies; - cache->prison = dm_bio_prison_create(); + cache->prison = dm_bio_prison_create_v2(cache->wq); if (!cache->prison) { *error = "could not create bio prison"; goto bad; } - cache->all_io_ds = dm_deferred_set_create(); - if (!cache->all_io_ds) { - *error = "could not create all_io deferred set"; - goto bad; - } - cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE, migration_cache); if (!cache->migration_pool) { @@ -2947,11 +2716,15 @@ static int cache_create(struct cache_args *ca, struct cache **result) spin_lock_init(&cache->invalidation_lock); INIT_LIST_HEAD(&cache->invalidation_requests); + batcher_init(&cache->committer, commit_op, cache, + issue_op, cache, cache->wq); iot_init(&cache->origin_tracker); + init_rwsem(&cache->background_work_lock); + prevent_background_work(cache); + *result = cache; return 0; - bad: destroy(cache); return r; @@ -3009,7 +2782,6 @@ static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv) } ti->private = cache; - out: destroy_cache_args(ca); return r; @@ -3022,17 +2794,11 @@ static int cache_map(struct dm_target *ti, struct bio *bio) struct cache *cache = ti->private; int r; - struct dm_bio_prison_cell *cell = NULL; + bool commit_needed; dm_oblock_t block = get_bio_block(cache, bio); size_t pb_data_size = get_per_bio_data_size(cache); - bool can_migrate = false; - bool fast_promotion; - struct policy_result lookup_result; - struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size); - struct old_oblock_lock ool; - - ool.locker.fn = null_locker; + init_per_bio_data(bio, pb_data_size); if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) { /* * This can only occur if the io goes to a partial block at @@ -3049,101 +2815,9 @@ static int cache_map(struct dm_target *ti, struct bio *bio) return DM_MAPIO_SUBMITTED; } - /* - * Check to see if that block is currently migrating. - */ - cell = alloc_prison_cell(cache); - if (!cell) { - defer_bio(cache, bio); - return DM_MAPIO_SUBMITTED; - } - - r = bio_detain(cache, block, bio, cell, - (cell_free_fn) free_prison_cell, - cache, &cell); - if (r) { - if (r < 0) - defer_bio(cache, bio); - - return DM_MAPIO_SUBMITTED; - } - - fast_promotion = is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio); - - r = policy_map(cache->policy, block, false, can_migrate, fast_promotion, - bio, &ool.locker, &lookup_result); - if (r == -EWOULDBLOCK) { - cell_defer(cache, cell, true); - return DM_MAPIO_SUBMITTED; - - } else if (r) { - DMERR_LIMIT("%s: Unexpected return from cache replacement policy: %d", - cache_device_name(cache), r); - cell_defer(cache, cell, false); - bio_io_error(bio); - return DM_MAPIO_SUBMITTED; - } - - r = DM_MAPIO_REMAPPED; - switch (lookup_result.op) { - case POLICY_HIT: - if (passthrough_mode(&cache->features)) { - if (bio_data_dir(bio) == WRITE) { - /* - * We need to invalidate this block, so - * defer for the worker thread. - */ - cell_defer(cache, cell, true); - r = DM_MAPIO_SUBMITTED; - - } else { - inc_miss_counter(cache, bio); - remap_to_origin_clear_discard(cache, bio, block); - accounted_begin(cache, bio); - inc_ds(cache, bio, cell); - // FIXME: we want to remap hits or misses straight - // away rather than passing over to the worker. - cell_defer(cache, cell, false); - } - - } else { - inc_hit_counter(cache, bio); - if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) && - !is_dirty(cache, lookup_result.cblock)) { - remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); - accounted_begin(cache, bio); - inc_ds(cache, bio, cell); - cell_defer(cache, cell, false); - - } else - remap_cell_to_cache_dirty(cache, cell, block, lookup_result.cblock, false); - } - break; - - case POLICY_MISS: - inc_miss_counter(cache, bio); - if (pb->req_nr != 0) { - /* - * This is a duplicate writethrough io that is no - * longer needed because the block has been demoted. - */ - bio_endio(bio); - // FIXME: remap everything as a miss - cell_defer(cache, cell, false); - r = DM_MAPIO_SUBMITTED; - - } else - remap_cell_to_origin_clear_discard(cache, cell, block, false); - break; - - default: - DMERR_LIMIT("%s: %s: erroring bio: unknown policy op: %u", - cache_device_name(cache), __func__, - (unsigned) lookup_result.op); - cell_defer(cache, cell, false); - bio_io_error(bio); - r = DM_MAPIO_SUBMITTED; - } + r = map_bio(cache, bio, block, &commit_needed); + if (commit_needed) + schedule_commit(&cache->committer); return r; } @@ -3163,7 +2837,7 @@ static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) spin_unlock_irqrestore(&cache->lock, flags); } - check_for_quiesced_migrations(cache, pb); + bio_drop_shared_lock(cache, bio); accounted_complete(cache, bio); return 0; @@ -3263,12 +2937,18 @@ static void cache_postsuspend(struct dm_target *ti) { struct cache *cache = ti->private; - start_quiescing(cache); - wait_for_migrations(cache); - stop_worker(cache); + prevent_background_work(cache); + BUG_ON(atomic_read(&cache->nr_io_migrations)); + + cancel_delayed_work(&cache->waker); + flush_workqueue(cache->wq); + WARN_ON(cache->origin_tracker.in_flight); + + /* + * If it's a flush suspend there won't be any deferred bios, so this + * call is harmless. + */ requeue_deferred_bios(cache); - requeue_deferred_cells(cache); - stop_quiescing(cache); if (get_cache_mode(cache) == CM_WRITE) (void) sync_metadata(cache); @@ -3280,15 +2960,10 @@ static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, int r; struct cache *cache = context; - r = policy_load_mapping(cache->policy, oblock, cblock, hint, hint_valid); + r = policy_load_mapping(cache->policy, oblock, cblock, dirty, hint, hint_valid); if (r) return r; - if (dirty) - set_dirty(cache, oblock, cblock); - else - clear_dirty(cache, oblock, cblock); - return 0; } @@ -3487,6 +3162,7 @@ static void cache_resume(struct dm_target *ti) struct cache *cache = ti->private; cache->need_tick_bio = true; + allow_background_work(cache); do_waker(&cache->waker.work); } @@ -3621,10 +3297,19 @@ err: } /* + * Defines a range of cblocks, begin to (end - 1) are in the range. end is + * the one-past-the-end value. + */ +struct cblock_range { + dm_cblock_t begin; + dm_cblock_t end; +}; + +/* * A cache block range can take two forms: * * i) A single cblock, eg. '3456' - * ii) A begin and end cblock with dots between, eg. 123-234 + * ii) A begin and end cblock with a dash between, eg. 123-234 */ static int parse_cblock_range(struct cache *cache, const char *str, struct cblock_range *result) @@ -3690,23 +3375,31 @@ static int validate_cblock_range(struct cache *cache, struct cblock_range *range return 0; } +static inline dm_cblock_t cblock_succ(dm_cblock_t b) +{ + return to_cblock(from_cblock(b) + 1); +} + static int request_invalidation(struct cache *cache, struct cblock_range *range) { - struct invalidation_request req; + int r = 0; - INIT_LIST_HEAD(&req.list); - req.cblocks = range; - atomic_set(&req.complete, 0); - req.err = 0; - init_waitqueue_head(&req.result_wait); + /* + * We don't need to do any locking here because we know we're in + * passthrough mode. There's is potential for a race between an + * invalidation triggered by an io and an invalidation message. This + * is harmless, we must not worry if the policy call fails. + */ + while (range->begin != range->end) { + r = invalidate_cblock(cache, range->begin); + if (r) + return r; - spin_lock(&cache->invalidation_lock); - list_add(&req.list, &cache->invalidation_requests); - spin_unlock(&cache->invalidation_lock); - wake_worker(cache); + range->begin = cblock_succ(range->begin); + } - wait_event(req.result_wait, atomic_read(&req.complete)); - return req.err; + cache->commit_requested = true; + return r; } static int process_invalidate_cblocks_message(struct cache *cache, unsigned count, @@ -3816,7 +3509,7 @@ static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) static struct target_type cache_target = { .name = "cache", - .version = {1, 10, 0}, + .version = {2, 0, 0}, .module = THIS_MODULE, .ctr = cache_ctr, .dtr = cache_dtr, |