| /* |
| * Copyright (C) 2012 Red Hat. All rights reserved. |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include "dm.h" |
| #include "dm-bio-prison-v2.h" |
| #include "dm-bio-record.h" |
| #include "dm-cache-metadata.h" |
| |
| #include <linux/dm-io.h> |
| #include <linux/dm-kcopyd.h> |
| #include <linux/jiffies.h> |
| #include <linux/init.h> |
| #include <linux/mempool.h> |
| #include <linux/module.h> |
| #include <linux/rwsem.h> |
| #include <linux/slab.h> |
| #include <linux/vmalloc.h> |
| |
| #define DM_MSG_PREFIX "cache" |
| |
| DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle, |
| "A percentage of time allocated for copying to and/or from cache"); |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * 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; |
| |
| /* |
| * Sectors of in-flight IO. |
| */ |
| sector_t in_flight; |
| |
| /* |
| * The time, in jiffies, when this device became idle (if it is |
| * indeed idle). |
| */ |
| unsigned long idle_time; |
| unsigned long last_update_time; |
| }; |
| |
| static void iot_init(struct io_tracker *iot) |
| { |
| spin_lock_init(&iot->lock); |
| iot->in_flight = 0ul; |
| iot->idle_time = 0ul; |
| iot->last_update_time = jiffies; |
| } |
| |
| static bool __iot_idle_for(struct io_tracker *iot, unsigned long jifs) |
| { |
| if (iot->in_flight) |
| return false; |
| |
| return time_after(jiffies, iot->idle_time + jifs); |
| } |
| |
| static bool iot_idle_for(struct io_tracker *iot, unsigned long jifs) |
| { |
| bool r; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&iot->lock, flags); |
| r = __iot_idle_for(iot, jifs); |
| spin_unlock_irqrestore(&iot->lock, flags); |
| |
| return r; |
| } |
| |
| static void iot_io_begin(struct io_tracker *iot, sector_t len) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&iot->lock, flags); |
| iot->in_flight += len; |
| spin_unlock_irqrestore(&iot->lock, flags); |
| } |
| |
| static void __iot_io_end(struct io_tracker *iot, sector_t len) |
| { |
| if (!len) |
| return; |
| |
| iot->in_flight -= len; |
| if (!iot->in_flight) |
| iot->idle_time = jiffies; |
| } |
| |
| static void iot_io_end(struct io_tracker *iot, sector_t len) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&iot->lock, flags); |
| __iot_io_end(iot, len); |
| spin_unlock_irqrestore(&iot->lock, flags); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * Represents a chunk of future work. 'input' allows continuations to pass |
| * values between themselves, typically error values. |
| */ |
| struct continuation { |
| struct work_struct ws; |
| blk_status_t 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. |
| */ |
| blk_status_t (*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); |
| blk_status_t 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_status = r; |
| bio_endio(bio); |
| } else |
| b->issue_op(bio, b->issue_context); |
| } |
| } |
| |
| static void batcher_init(struct batcher *b, |
| blk_status_t (*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. |
| */ |
| struct dm_hook_info { |
| bio_end_io_t *bi_end_io; |
| }; |
| |
| static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio, |
| bio_end_io_t *bi_end_io, void *bi_private) |
| { |
| h->bi_end_io = bio->bi_end_io; |
| |
| bio->bi_end_io = bi_end_io; |
| bio->bi_private = bi_private; |
| } |
| |
| static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio) |
| { |
| bio->bi_end_io = h->bi_end_io; |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| #define MIGRATION_POOL_SIZE 128 |
| #define COMMIT_PERIOD HZ |
| #define MIGRATION_COUNT_WINDOW 10 |
| |
| /* |
| * The block size of the device holding cache data must be |
| * between 32KB and 1GB. |
| */ |
| #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) |
| #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) |
| |
| enum cache_metadata_mode { |
| CM_WRITE, /* metadata may be changed */ |
| CM_READ_ONLY, /* metadata may not be changed */ |
| CM_FAIL |
| }; |
| |
| enum cache_io_mode { |
| /* |
| * Data is written to cached blocks only. These blocks are marked |
| * dirty. If you lose the cache device you will lose data. |
| * Potential performance increase for both reads and writes. |
| */ |
| CM_IO_WRITEBACK, |
| |
| /* |
| * Data is written to both cache and origin. Blocks are never |
| * dirty. Potential performance benfit for reads only. |
| */ |
| CM_IO_WRITETHROUGH, |
| |
| /* |
| * A degraded mode useful for various cache coherency situations |
| * (eg, rolling back snapshots). Reads and writes always go to the |
| * origin. If a write goes to a cached oblock, then the cache |
| * block is invalidated. |
| */ |
| CM_IO_PASSTHROUGH |
| }; |
| |
| struct cache_features { |
| enum cache_metadata_mode mode; |
| enum cache_io_mode io_mode; |
| unsigned metadata_version; |
| }; |
| |
| struct cache_stats { |
| atomic_t read_hit; |
| atomic_t read_miss; |
| atomic_t write_hit; |
| 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; |
| }; |
| |
| struct cache { |
| struct dm_target *ti; |
| struct dm_target_callbacks callbacks; |
| |
| struct dm_cache_metadata *cmd; |
| |
| /* |
| * Metadata is written to this device. |
| */ |
| struct dm_dev *metadata_dev; |
| |
| /* |
| * The slower of the two data devices. Typically a spindle. |
| */ |
| struct dm_dev *origin_dev; |
| |
| /* |
| * The faster of the two data devices. Typically an SSD. |
| */ |
| struct dm_dev *cache_dev; |
| |
| /* |
| * Size of the origin device in _complete_ blocks and native sectors. |
| */ |
| dm_oblock_t origin_blocks; |
| sector_t origin_sectors; |
| |
| /* |
| * Size of the cache device in blocks. |
| */ |
| dm_cblock_t cache_size; |
| |
| /* |
| * Fields for converting from sectors to blocks. |
| */ |
| sector_t sectors_per_block; |
| int sectors_per_block_shift; |
| |
| spinlock_t lock; |
| struct list_head deferred_cells; |
| struct bio_list deferred_bios; |
| struct bio_list deferred_writethrough_bios; |
| sector_t migration_threshold; |
| wait_queue_head_t migration_wait; |
| atomic_t nr_allocated_migrations; |
| |
| /* |
| * The number of in flight migrations that are performing |
| * background io. eg, promotion, writeback. |
| */ |
| atomic_t nr_io_migrations; |
| |
| struct rw_semaphore quiesce_lock; |
| |
| /* |
| * cache_size entries, dirty if set |
| */ |
| atomic_t nr_dirty; |
| unsigned long *dirty_bitset; |
| |
| /* |
| * origin_blocks entries, discarded if set. |
| */ |
| dm_dblock_t discard_nr_blocks; |
| unsigned long *discard_bitset; |
| uint32_t discard_block_size; /* a power of 2 times sectors per block */ |
| |
| /* |
| * Rather than reconstructing the table line for the status we just |
| * save it and regurgitate. |
| */ |
| unsigned nr_ctr_args; |
| const char **ctr_args; |
| |
| struct dm_kcopyd_client *copier; |
| struct workqueue_struct *wq; |
| struct work_struct deferred_bio_worker; |
| struct work_struct deferred_writethrough_worker; |
| struct work_struct migration_worker; |
| struct delayed_work waker; |
| struct dm_bio_prison_v2 *prison; |
| |
| mempool_t *migration_pool; |
| |
| struct dm_cache_policy *policy; |
| unsigned policy_nr_args; |
| |
| bool need_tick_bio:1; |
| bool sized:1; |
| bool invalidate:1; |
| bool commit_requested:1; |
| bool loaded_mappings:1; |
| bool loaded_discards:1; |
| |
| /* |
| * Cache features such as write-through. |
| */ |
| struct cache_features features; |
| |
| struct cache_stats stats; |
| |
| /* |
| * Invalidation fields. |
| */ |
| spinlock_t invalidation_lock; |
| struct list_head invalidation_requests; |
| |
| struct io_tracker 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_bio_prison_cell_v2 *cell; |
| struct dm_hook_info hook_info; |
| sector_t len; |
| |
| /* |
| * writethrough fields. These MUST remain at the end of this |
| * structure and the 'cache' member must be the first as it |
| * is used to determine the offset of the writethrough fields. |
| */ |
| struct cache *cache; |
| dm_cblock_t cblock; |
| struct dm_bio_details bio_details; |
| }; |
| |
| struct dm_cache_migration { |
| struct continuation k; |
| struct cache *cache; |
| |
| struct policy_work *op; |
| struct bio *overwrite_bio; |
| struct dm_bio_prison_cell_v2 *cell; |
| |
| dm_cblock_t invalidate_cblock; |
| dm_oblock_t invalidate_oblock; |
| }; |
| |
| /*----------------------------------------------------------------*/ |
| |
| 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 inline bool passthrough_mode(struct cache_features *f) |
| { |
| return unlikely(f->io_mode == CM_IO_PASSTHROUGH); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static void wake_deferred_bio_worker(struct cache *cache) |
| { |
| queue_work(cache->wq, &cache->deferred_bio_worker); |
| } |
| |
| static void wake_deferred_writethrough_worker(struct cache *cache) |
| { |
| 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) |
| { |
| struct dm_cache_migration *mg; |
| |
| mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT); |
| if (mg) { |
| mg->cache = cache; |
| atomic_inc(&mg->cache->nr_allocated_migrations); |
| } |
| |
| return mg; |
| } |
| |
| static void free_migration(struct dm_cache_migration *mg) |
| { |
| struct cache *cache = mg->cache; |
| |
| if (atomic_dec_and_test(&cache->nr_allocated_migrations)) |
| wake_up(&cache->migration_wait); |
| |
| mempool_free(mg, cache->migration_pool); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static inline dm_oblock_t oblock_succ(dm_oblock_t b) |
| { |
| return to_oblock(from_oblock(b) + 1ull); |
| } |
| |
| static void build_key(dm_oblock_t begin, dm_oblock_t end, struct dm_cell_key_v2 *key) |
| { |
| key->virtual = 0; |
| key->dev = 0; |
| key->block_begin = from_oblock(begin); |
| key->block_end = from_oblock(end); |
| } |
| |
| /* |
| * We have two lock levels. Level 0, which is used to prevent WRITEs, and |
| * level 1 which prevents *both* READs and WRITEs. |
| */ |
| #define WRITE_LOCK_LEVEL 0 |
| #define READ_WRITE_LOCK_LEVEL 1 |
| |
| static unsigned lock_level(struct bio *bio) |
| { |
| return bio_data_dir(bio) == WRITE ? |
| WRITE_LOCK_LEVEL : |
| READ_WRITE_LOCK_LEVEL; |
| } |
| |
| /*---------------------------------------------------------------- |
| * 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 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->cell = NULL; |
| pb->len = 0; |
| |
| return pb; |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static void defer_bio(struct cache *cache, struct bio *bio) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&cache->lock, flags); |
| bio_list_add(&cache->deferred_bios, bio); |
| spin_unlock_irqrestore(&cache->lock, flags); |
| |
| wake_deferred_bio_worker(cache); |
| } |
| |
| static void defer_bios(struct cache *cache, struct bio_list *bios) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&cache->lock, flags); |
| bio_list_merge(&cache->deferred_bios, bios); |
| bio_list_init(bios); |
| spin_unlock_irqrestore(&cache->lock, flags); |
| |
| wake_deferred_bio_worker(cache); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| 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); |
| struct dm_bio_prison_cell_v2 *cell_prealloc, *cell; |
| |
| cell_prealloc = alloc_prison_cell(cache); /* FIXME: allow wait if calling from worker */ |
| if (!cell_prealloc) { |
| defer_bio(cache, bio); |
| return false; |
| } |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| 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_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); |
| } |
| } |
| |
| /* |
| * 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)) { |
| if (atomic_dec_return(&cache->nr_dirty) == 0) |
| dm_table_event(cache->ti->table); |
| } |
| |
| policy_clear_dirty(cache->policy, cblock); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static bool block_size_is_power_of_two(struct cache *cache) |
| { |
| return cache->sectors_per_block_shift >= 0; |
| } |
| |
| /* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */ |
| #if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6 |
| __always_inline |
| #endif |
| static dm_block_t block_div(dm_block_t b, uint32_t n) |
| { |
| do_div(b, n); |
| |
| return b; |
| } |
| |
| static dm_block_t oblocks_per_dblock(struct cache *cache) |
| { |
| dm_block_t oblocks = cache->discard_block_size; |
| |
| if (block_size_is_power_of_two(cache)) |
| oblocks >>= cache->sectors_per_block_shift; |
| else |
| oblocks = block_div(oblocks, cache->sectors_per_block); |
| |
| return oblocks; |
| } |
| |
| static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) |
| { |
| return to_dblock(block_div(from_oblock(oblock), |
| oblocks_per_dblock(cache))); |
| } |
| |
| static void set_discard(struct cache *cache, dm_dblock_t b) |
| { |
| unsigned long flags; |
| |
| BUG_ON(from_dblock(b) >= from_dblock(cache->discard_nr_blocks)); |
| atomic_inc(&cache->stats.discard_count); |
| |
| spin_lock_irqsave(&cache->lock, flags); |
| set_bit(from_dblock(b), cache->discard_bitset); |
| spin_unlock_irqrestore(&cache->lock, flags); |
| } |
| |
| static void clear_discard(struct cache *cache, dm_dblock_t b) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&cache->lock, flags); |
| clear_bit(from_dblock(b), cache->discard_bitset); |
| spin_unlock_irqrestore(&cache->lock, flags); |
| } |
| |
| static bool is_discarded(struct cache *cache, dm_dblock_t b) |
| { |
| int r; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&cache->lock, flags); |
| r = test_bit(from_dblock(b), cache->discard_bitset); |
| spin_unlock_irqrestore(&cache->lock, flags); |
| |
| return r; |
| } |
| |
| static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) |
| { |
| int r; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&cache->lock, flags); |
| r = test_bit(from_dblock(oblock_to_dblock(cache, b)), |
| cache->discard_bitset); |
| spin_unlock_irqrestore(&cache->lock, flags); |
| |
| return r; |
| } |
| |
| /*---------------------------------------------------------------- |
| * Remapping |
| *--------------------------------------------------------------*/ |
| static void remap_to_origin(struct cache *cache, struct bio *bio) |
| { |
| bio_set_dev(bio, cache->origin_dev->bdev); |
| } |
| |
| static void remap_to_cache(struct cache *cache, struct bio *bio, |
| dm_cblock_t cblock) |
| { |
| sector_t bi_sector = bio->bi_iter.bi_sector; |
| sector_t block = from_cblock(cblock); |
| |
| bio_set_dev(bio, cache->cache_dev->bdev); |
| if (!block_size_is_power_of_two(cache)) |
| bio->bi_iter.bi_sector = |
| (block * cache->sectors_per_block) + |
| sector_div(bi_sector, cache->sectors_per_block); |
| else |
| bio->bi_iter.bi_sector = |
| (block << cache->sectors_per_block_shift) | |
| (bi_sector & (cache->sectors_per_block - 1)); |
| } |
| |
| static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) |
| { |
| unsigned long flags; |
| size_t pb_data_size = get_per_bio_data_size(cache); |
| struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); |
| |
| spin_lock_irqsave(&cache->lock, flags); |
| if (cache->need_tick_bio && !op_is_flush(bio->bi_opf) && |
| bio_op(bio) != REQ_OP_DISCARD) { |
| pb->tick = true; |
| cache->need_tick_bio = false; |
| } |
| spin_unlock_irqrestore(&cache->lock, flags); |
| } |
| |
| static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, |
| 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) |
| clear_discard(cache, oblock_to_dblock(cache, oblock)); |
| } |
| |
| static void remap_to_cache_dirty(struct cache *cache, struct bio *bio, |
| dm_oblock_t oblock, dm_cblock_t cblock) |
| { |
| check_if_tick_bio_needed(cache, bio); |
| remap_to_cache(cache, bio, cblock); |
| if (bio_data_dir(bio) == WRITE) { |
| set_dirty(cache, cblock); |
| clear_discard(cache, oblock_to_dblock(cache, oblock)); |
| } |
| } |
| |
| static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) |
| { |
| sector_t block_nr = bio->bi_iter.bi_sector; |
| |
| if (!block_size_is_power_of_two(cache)) |
| (void) sector_div(block_nr, cache->sectors_per_block); |
| else |
| block_nr >>= cache->sectors_per_block_shift; |
| |
| return to_oblock(block_nr); |
| } |
| |
| static bool accountable_bio(struct cache *cache, struct bio *bio) |
| { |
| return bio_op(bio) != REQ_OP_DISCARD; |
| } |
| |
| static void accounted_begin(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 (accountable_bio(cache, bio)) { |
| pb->len = bio_sectors(bio); |
| iot_io_begin(&cache->tracker, pb->len); |
| } |
| } |
| |
| static void accounted_complete(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); |
| |
| iot_io_end(&cache->tracker, pb->len); |
| } |
| |
| static void accounted_request(struct cache *cache, struct bio *bio) |
| { |
| accounted_begin(cache, bio); |
| generic_make_request(bio); |
| } |
| |
| static void issue_op(struct bio *bio, void *context) |
| { |
| struct cache *cache = context; |
| accounted_request(cache, bio); |
| } |
| |
| static void defer_writethrough_bio(struct cache *cache, struct bio *bio) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&cache->lock, flags); |
| bio_list_add(&cache->deferred_writethrough_bios, bio); |
| spin_unlock_irqrestore(&cache->lock, flags); |
| |
| wake_deferred_writethrough_worker(cache); |
| } |
| |
| static void writethrough_endio(struct bio *bio) |
| { |
| struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
| |
| dm_unhook_bio(&pb->hook_info, bio); |
| |
| if (bio->bi_status) { |
| bio_endio(bio); |
| return; |
| } |
| |
| dm_bio_restore(&pb->bio_details, bio); |
| remap_to_cache(pb->cache, bio, pb->cblock); |
| |
| /* |
| * We can't issue this bio directly, since we're in interrupt |
| * context. So it gets put on a bio list for processing by the |
| * worker thread. |
| */ |
| defer_writethrough_bio(pb->cache, 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 |
| * series as this is easier. |
| */ |
| static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, |
| dm_oblock_t oblock, dm_cblock_t cblock) |
| { |
| struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); |
| |
| pb->cache = cache; |
| pb->cblock = cblock; |
| dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL); |
| dm_bio_record(&pb->bio_details, bio); |
| |
| remap_to_origin_clear_discard(pb->cache, bio, oblock); |
| } |
| |
| /*---------------------------------------------------------------- |
| * Failure modes |
| *--------------------------------------------------------------*/ |
| static enum cache_metadata_mode get_cache_mode(struct cache *cache) |
| { |
| return cache->features.mode; |
| } |
| |
| static const char *cache_device_name(struct cache *cache) |
| { |
| return dm_device_name(dm_table_get_md(cache->ti->table)); |
| } |
| |
| static void notify_mode_switch(struct cache *cache, enum cache_metadata_mode mode) |
| { |
| const char *descs[] = { |
| "write", |
| "read-only", |
| "fail" |
| }; |
| |
| dm_table_event(cache->ti->table); |
| DMINFO("%s: switching cache to %s mode", |
| cache_device_name(cache), descs[(int)mode]); |
| } |
| |
| static void set_cache_mode(struct cache *cache, enum cache_metadata_mode new_mode) |
| { |
| bool needs_check; |
| enum cache_metadata_mode old_mode = get_cache_mode(cache); |
| |
| if (dm_cache_metadata_needs_check(cache->cmd, &needs_check)) { |
| DMERR("%s: unable to read needs_check flag, setting failure mode.", |
| cache_device_name(cache)); |
| new_mode = CM_FAIL; |
| } |
| |
| if (new_mode == CM_WRITE && needs_check) { |
| DMERR("%s: unable to switch cache to write mode until repaired.", |
| cache_device_name(cache)); |
| if (old_mode != new_mode) |
| new_mode = old_mode; |
| else |
| new_mode = CM_READ_ONLY; |
| } |
| |
| /* Never move out of fail mode */ |
| if (old_mode == CM_FAIL) |
| new_mode = CM_FAIL; |
| |
| switch (new_mode) { |
| case CM_FAIL: |
| case CM_READ_ONLY: |
| dm_cache_metadata_set_read_only(cache->cmd); |
| break; |
| |
| case CM_WRITE: |
| dm_cache_metadata_set_read_write(cache->cmd); |
| break; |
| } |
| |
| cache->features.mode = new_mode; |
| |
| if (new_mode != old_mode) |
| notify_mode_switch(cache, new_mode); |
| } |
| |
| static void abort_transaction(struct cache *cache) |
| { |
| const char *dev_name = cache_device_name(cache); |
| |
| if (get_cache_mode(cache) >= CM_READ_ONLY) |
| return; |
| |
| if (dm_cache_metadata_set_needs_check(cache->cmd)) { |
| DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name); |
| set_cache_mode(cache, CM_FAIL); |
| } |
| |
| DMERR_LIMIT("%s: aborting current metadata transaction", dev_name); |
| if (dm_cache_metadata_abort(cache->cmd)) { |
| DMERR("%s: failed to abort metadata transaction", dev_name); |
| set_cache_mode(cache, CM_FAIL); |
| } |
| } |
| |
| static void metadata_operation_failed(struct cache *cache, const char *op, int r) |
| { |
| DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d", |
| cache_device_name(cache), op, r); |
| abort_transaction(cache); |
| 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); |
| } |
| |
| static void dec_io_migrations(struct cache *cache) |
| { |
| atomic_dec(&cache->nr_io_migrations); |
| } |
| |
| static bool discard_or_flush(struct bio *bio) |
| { |
| return bio_op(bio) == REQ_OP_DISCARD || op_is_flush(bio->bi_opf); |
| } |
| |
| 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); |
| |
| *b = to_dblock(dm_sector_div_up(sb, cache->discard_block_size)); |
| |
| if (se - sb < cache->discard_block_size) |
| *e = *b; |
| else |
| *e = to_dblock(block_div(se, cache->discard_block_size)); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static void prevent_background_work(struct cache *cache) |
| { |
| lockdep_off(); |
| down_write(&cache->background_work_lock); |
| lockdep_on(); |
| } |
| |
| static void allow_background_work(struct cache *cache) |
| { |
| lockdep_off(); |
| up_write(&cache->background_work_lock); |
| lockdep_on(); |
| } |
| |
| static bool background_work_begin(struct cache *cache) |
| { |
| bool r; |
| |
| lockdep_off(); |
| r = down_read_trylock(&cache->background_work_lock); |
| lockdep_on(); |
| |
| return r; |
| } |
| |
| static void background_work_end(struct cache *cache) |
| { |
| lockdep_off(); |
| up_read(&cache->background_work_lock); |
| lockdep_on(); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| 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 struct dm_cache_migration *ws_to_mg(struct work_struct *ws) |
| { |
| 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) |
| { |
| struct dm_cache_migration *mg = container_of(context, struct dm_cache_migration, k); |
| |
| if (read_err || write_err) |
| mg->k.input = BLK_STS_IOERR; |
| |
| queue_continuation(mg->cache->wq, &mg->k); |
| } |
| |
| 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; |
| |
| 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 = from_cblock(mg->op->cblock) * cache->sectors_per_block; |
| c_region.count = cache->sectors_per_block; |
| |
| 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); |
| |
| 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) |
| { |
| struct dm_cache_migration *mg = bio->bi_private; |
| 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); |
| |
| dm_unhook_bio(&pb->hook_info, bio); |
| |
| if (bio->bi_status) |
| mg->k.input = bio->bi_status; |
| |
| queue_continuation(mg->cache->wq, &mg->k); |
| } |
| |
| 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); |
| |
| /* |
| * 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); |
| } |
| |
| /* |
| * 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) |
| { |
| 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 if (mg->k.input) |
| mg->overwrite_bio->bi_status = mg->k.input; |
| else |
| mg->overwrite_bio->bi_status = BLK_STS_IOERR; |
| bio_endio(mg->overwrite_bio); |
| } else { |
| if (success) |
| force_clear_dirty(cache, cblock); |
| dec_io_migrations(cache); |
| } |
| break; |
| |
| 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; |
| |
| case POLICY_WRITEBACK: |
| if (success) |
| force_clear_dirty(cache, cblock); |
| policy_complete_background_work(cache->policy, op, success); |
| dec_io_migrations(cache); |
| break; |
| } |
| |
| bio_list_init(&bios); |
| if (mg->cell) { |
| if (dm_cell_unlock_v2(cache->prison, mg->cell, &bios)) |
| free_prison_cell(cache, mg->cell); |
| } |
| |
| free_migration(mg); |
| defer_bios(cache, &bios); |
| wake_migration_worker(cache); |
| |
| background_work_end(cache); |
| } |
| |
| static void mg_success(struct work_struct *ws) |
| { |
| struct dm_cache_migration *mg = ws_to_mg(ws); |
| mg_complete(mg, mg->k.input == 0); |
| } |
| |
| static void mg_update_metadata(struct work_struct *ws) |
| { |
| int r; |
| struct dm_cache_migration *mg = ws_to_mg(ws); |
| struct cache *cache = mg->cache; |
| struct policy_work *op = mg->op; |
| |
| 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); |
| |
| mg_complete(mg, false); |
| return; |
| } |
| mg_complete(mg, true); |
| break; |
| |
| 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); |
| |
| mg_complete(mg, false); |
| return; |
| } |
| |
| /* |
| * 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 mg_update_metadata_after_copy(struct work_struct *ws) |
| { |
| struct dm_cache_migration *mg = ws_to_mg(ws); |
| |
| /* |
| * Did the copy succeed? |
| */ |
| if (mg->k.input) |
| mg_complete(mg, false); |
| else |
| mg_update_metadata(ws); |
| } |
| |
| static void mg_upgrade_lock(struct work_struct *ws) |
| { |
| int r; |
| struct dm_cache_migration *mg = ws_to_mg(ws); |
| |
| /* |
| * Did the copy succeed? |
| */ |
| if (mg->k.input) |
| mg_complete(mg, false); |
| |
| 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); |
| |
| else if (r) |
| quiesce(mg, mg_update_metadata); |
| |
| else |
| mg_update_metadata(ws); |
| } |
| } |
| |
| static void mg_copy(struct work_struct *ws) |
| { |
| int r; |
| struct dm_cache_migration *mg = ws_to_mg(ws); |
| |
| 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); |
| |
| } else { |
| struct cache *cache = mg->cache; |
| struct policy_work *op = mg->op; |
| bool is_policy_promote = (op->op == POLICY_PROMOTE); |
| |
| if ((!is_policy_promote && !is_dirty(cache, op->cblock)) || |
| is_discarded_oblock(cache, op->oblock)) { |
| mg_upgrade_lock(ws); |
| return; |
| } |
| |
| init_continuation(&mg->k, mg_upgrade_lock); |
| |
| r = copy(mg, is_policy_promote); |
| if (r) { |
| DMERR_LIMIT("%s: migration copy failed", cache_device_name(cache)); |
| mg->k.input = BLK_STS_IOERR; |
| mg_complete(mg, false); |
| } |
| } |
| } |
| |
| static int mg_lock_writes(struct dm_cache_migration *mg) |
| { |
| int r; |
| struct dm_cell_key_v2 key; |
| struct cache *cache = mg->cache; |
| struct dm_bio_prison_cell_v2 *prealloc; |
| |
| 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; |
| } |
| |
| if (mg->cell != prealloc) |
| free_prison_cell(cache, prealloc); |
| |
| if (r == 0) |
| mg_copy(&mg->k.ws); |
| else |
| quiesce(mg, mg_copy); |
| |
| return 0; |
| } |
| |
| static int mg_start(struct cache *cache, struct policy_work *op, struct bio *bio) |
| { |
| 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->cache = cache; |
| mg->op = op; |
| mg->overwrite_bio = bio; |
| |
| if (!bio) |
| inc_io_migrations(cache); |
| |
| return mg_lock_writes(mg); |
| } |
| |
| /*---------------------------------------------------------------- |
| * invalidation processing |
| *--------------------------------------------------------------*/ |
| |
| static void invalidate_complete(struct dm_cache_migration *mg, bool success) |
| { |
| struct bio_list bios; |
| struct cache *cache = mg->cache; |
| |
| bio_list_init(&bios); |
| if (dm_cell_unlock_v2(cache->prison, mg->cell, &bios)) |
| free_prison_cell(cache, mg->cell); |
| |
| if (!success && mg->overwrite_bio) |
| bio_io_error(mg->overwrite_bio); |
| |
| free_migration(mg); |
| defer_bios(cache, &bios); |
| |
| background_work_end(cache); |
| } |
| |
| static void invalidate_completed(struct work_struct *ws) |
| { |
| struct dm_cache_migration *mg = ws_to_mg(ws); |
| invalidate_complete(mg, !mg->k.input); |
| } |
| |
| 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)); |
| |
| return r; |
| } |
| |
| static void invalidate_remove(struct work_struct *ws) |
| { |
| int r; |
| struct dm_cache_migration *mg = ws_to_mg(ws); |
| struct cache *cache = mg->cache; |
| |
| r = invalidate_cblock(cache, mg->invalidate_cblock); |
| if (r) { |
| invalidate_complete(mg, false); |
| return; |
| } |
| |
| 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 int invalidate_lock(struct dm_cache_migration *mg) |
| { |
| int r; |
| struct dm_cell_key_v2 key; |
| struct cache *cache = mg->cache; |
| struct dm_bio_prison_cell_v2 *prealloc; |
| |
| prealloc = alloc_prison_cell(cache); |
| if (!prealloc) { |
| invalidate_complete(mg, false); |
| return -ENOMEM; |
| } |
| |
| 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 int invalidate_start(struct cache *cache, dm_cblock_t cblock, |
| dm_oblock_t oblock, struct bio *bio) |
| { |
| struct dm_cache_migration *mg; |
| |
| if (!background_work_begin(cache)) |
| return -EPERM; |
| |
| mg = alloc_migration(cache); |
| if (!mg) { |
| background_work_end(cache); |
| return -ENOMEM; |
| } |
| |
| memset(mg, 0, sizeof(*mg)); |
| |
| mg->cache = cache; |
| mg->overwrite_bio = bio; |
| mg->invalidate_cblock = cblock; |
| mg->invalidate_oblock = oblock; |
| |
| return invalidate_lock(mg); |
| } |
| |
| /*---------------------------------------------------------------- |
| * bio processing |
| *--------------------------------------------------------------*/ |
| |
| enum busy { |
| IDLE, |
| BUSY |
| }; |
| |
| static enum busy spare_migration_bandwidth(struct cache *cache) |
| { |
| bool idle = iot_idle_for(&cache->tracker, HZ); |
| sector_t current_volume = (atomic_read(&cache->nr_io_migrations) + 1) * |
| cache->sectors_per_block; |
| |
| if (idle && current_volume <= cache->migration_threshold) |
| return IDLE; |
| else |
| return BUSY; |
| } |
| |
| static void inc_hit_counter(struct cache *cache, struct bio *bio) |
| { |
| atomic_inc(bio_data_dir(bio) == READ ? |
| &cache->stats.read_hit : &cache->stats.write_hit); |
| } |
| |
| static void inc_miss_counter(struct cache *cache, struct bio *bio) |
| { |
| atomic_inc(bio_data_dir(bio) == READ ? |
| &cache->stats.read_miss : &cache->stats.write_miss); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static bool bio_writes_complete_block(struct cache *cache, struct bio *bio) |
| { |
| return (bio_data_dir(bio) == WRITE) && |
| (bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT)); |
| } |
| |
| static bool optimisable_bio(struct cache *cache, struct bio *bio, dm_oblock_t block) |
| { |
| return writeback_mode(&cache->features) && |
| (is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio)); |
| } |
| |
| static int map_bio(struct cache *cache, struct bio *bio, dm_oblock_t block, |
| bool *commit_needed) |
| { |
| 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); |
| |
| *commit_needed = false; |
| |
| 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; |
| } |
| |
| data_dir = bio_data_dir(bio); |
| |
| if (optimisable_bio(cache, bio, block)) { |
| struct policy_work *op = NULL; |
| |
| 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; |
| } |
| |
| 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; |
| } |
| |
| if (background_queued) |
| wake_migration_worker(cache); |
| } |
| |
| 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 { |
| /* |
| * 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_start(cache, cblock, block, bio); |
| } else |
| remap_to_origin_clear_discard(cache, bio, block); |
| |
| } else { |
| 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); |
| } |
| } |
| |
| /* |
| * dm core turns FUA requests into a separate payload and FLUSH req. |
| */ |
| 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; |
| } |
| |
| return DM_MAPIO_REMAPPED; |
| } |
| |
| static bool process_bio(struct cache *cache, struct bio *bio) |
| { |
| 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; |
| } |
| |
| /* |
| * A non-zero return indicates read_only or fail_io mode. |
| */ |
| static int commit(struct cache *cache, bool clean_shutdown) |
| { |
| int r; |
| |
| if (get_cache_mode(cache) >= CM_READ_ONLY) |
| return -EINVAL; |
| |
| atomic_inc(&cache->stats.commit_count); |
| r = dm_cache_commit(cache->cmd, clean_shutdown); |
| if (r) |
| metadata_operation_failed(cache, "dm_cache_commit", r); |
| |
| return r; |
| } |
| |
| /* |
| * Used by the batcher. |
| */ |
| static blk_status_t commit_op(void *context) |
| { |
| struct cache *cache = context; |
| |
| if (dm_cache_changed_this_transaction(cache->cmd)) |
| return errno_to_blk_status(commit(cache, false)); |
| |
| return 0; |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| 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 (!pb->req_nr) |
| remap_to_origin(cache, bio); |
| else |
| remap_to_cache(cache, bio, 0); |
| |
| issue_after_commit(&cache->committer, bio); |
| return true; |
| } |
| |
| static bool process_discard_bio(struct cache *cache, struct bio *bio) |
| { |
| dm_dblock_t b, e; |
| |
| // 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); |
| } |
| |
| bio_endio(bio); |
| |
| return false; |
| } |
| |
| 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_bios); |
| bio_list_init(&cache->deferred_bios); |
| spin_unlock_irqrestore(&cache->lock, flags); |
| |
| 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 work_struct *ws) |
| { |
| struct cache *cache = container_of(ws, struct cache, deferred_writethrough_worker); |
| |
| unsigned long flags; |
| struct bio_list bios; |
| struct bio *bio; |
| |
| bio_list_init(&bios); |
| |
| spin_lock_irqsave(&cache->lock, flags); |
| bio_list_merge(&bios, &cache->deferred_writethrough_bios); |
| bio_list_init(&cache->deferred_writethrough_bios); |
| spin_unlock_irqrestore(&cache->lock, flags); |
| |
| /* |
| * These bios have already been through accounted_begin() |
| */ |
| while ((bio = bio_list_pop(&bios))) |
| generic_make_request(bio); |
| } |
| |
| /*---------------------------------------------------------------- |
| * Main worker loop |
| *--------------------------------------------------------------*/ |
| |
| static void requeue_deferred_bios(struct cache *cache) |
| { |
| struct bio *bio; |
| struct bio_list bios; |
| |
| bio_list_init(&bios); |
| bio_list_merge(&bios, &cache->deferred_bios); |
| bio_list_init(&cache->deferred_bios); |
| |
| while ((bio = bio_list_pop(&bios))) { |
| bio->bi_status = BLK_STS_DM_REQUEUE; |
| bio_endio(bio); |
| } |
| } |
| |
| /* |
| * We want to commit periodically so that not too much |
| * unwritten metadata builds up. |
| */ |
| 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_migration_worker(cache); |
| schedule_commit(&cache->committer); |
| queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); |
| } |
| |
| static void check_migrations(struct work_struct *ws) |
| { |
| int r; |
| struct policy_work *op; |
| struct cache *cache = container_of(ws, struct cache, migration_worker); |
| enum busy b; |
| |
| for (;;) { |
| b = spare_migration_bandwidth(cache); |
| |
| 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; |
| } |
| } |
| |
| /*---------------------------------------------------------------- |
| * Target methods |
| *--------------------------------------------------------------*/ |
| |
| /* |
| * This function gets called on the error paths of the constructor, so we |
| * have to cope with a partially initialised struct. |
| */ |
| static void destroy(struct cache *cache) |
| { |
| unsigned i; |
| |
| mempool_destroy(cache->migration_pool); |
| |
| if (cache->prison) |
| dm_bio_prison_destroy_v2(cache->prison); |
| |
| if (cache->wq) |
| destroy_workqueue(cache->wq); |
| |
| if (cache->dirty_bitset) |
| free_bitset(cache->dirty_bitset); |
| |
| if (cache->discard_bitset) |
| free_bitset(cache->discard_bitset); |
| |
| if (cache->copier) |
| dm_kcopyd_client_destroy(cache->copier); |
| |
| if (cache->cmd) |
| dm_cache_metadata_close(cache->cmd); |
| |
| if (cache->metadata_dev) |
| dm_put_device(cache->ti, cache->metadata_dev); |
| |
| if (cache->origin_dev) |
| dm_put_device(cache->ti, cache->origin_dev); |
| |
| if (cache->cache_dev) |
| dm_put_device(cache->ti, cache->cache_dev); |
| |
| if (cache->policy) |
| dm_cache_policy_destroy(cache->policy); |
| |
| for (i = 0; i < cache->nr_ctr_args ; i++) |
| kfree(cache->ctr_args[i]); |
| kfree(cache->ctr_args); |
| |
| kfree(cache); |
| } |
| |
| static void cache_dtr(struct dm_target *ti) |
| { |
| struct cache *cache = ti->private; |
| |
| destroy(cache); |
| } |
| |
| static sector_t get_dev_size(struct dm_dev *dev) |
| { |
| return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT; |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * Construct a cache device mapping. |
| * |
| * cache <metadata dev> <cache dev> <origin dev> <block size> |
| * <#feature args> [<feature arg>]* |
| * <policy> <#policy args> [<policy arg>]* |
| * |
| * metadata dev : fast device holding the persistent metadata |
| * cache dev : fast device holding cached data blocks |
| * origin dev : slow device holding original data blocks |
| * block size : cache unit size in sectors |
| * |
| * #feature args : number of feature arguments passed |
| * feature args : writethrough. (The default is writeback.) |
| * |
| * policy : the replacement policy to use |
| * #policy args : an even number of policy arguments corresponding |
| * to key/value pairs passed to the policy |
| * policy args : key/value pairs passed to the policy |
| * E.g. 'sequential_threshold 1024' |
| * See cache-policies.txt for details. |
| * |
| * Optional feature arguments are: |
| * writethrough : write through caching that prohibits cache block |
| * content from being different from origin block content. |
| * Without this argument, the default behaviour is to write |
| * back cache block contents later for performance reasons, |
| * so they may differ from the corresponding origin blocks. |
| */ |
| struct cache_args { |
| struct dm_target *ti; |
| |
| struct dm_dev *metadata_dev; |
| |
| struct dm_dev *cache_dev; |
| sector_t cache_sectors; |
| |
| struct dm_dev *origin_dev; |
| sector_t origin_sectors; |
| |
| uint32_t block_size; |
| |
| const char *policy_name; |
| int policy_argc; |
| const char **policy_argv; |
| |
| struct cache_features features; |
| }; |
| |
| static void destroy_cache_args(struct cache_args *ca) |
| { |
| if (ca->metadata_dev) |
| dm_put_device(ca->ti, ca->metadata_dev); |
| |
| if (ca->cache_dev) |
| dm_put_device(ca->ti, ca->cache_dev); |
| |
| if (ca->origin_dev) |
| dm_put_device(ca->ti, ca->origin_dev); |
| |
| kfree(ca); |
| } |
| |
| static bool at_least_one_arg(struct dm_arg_set *as, char **error) |
| { |
| if (!as->argc) { |
| *error = "Insufficient args"; |
| return false; |
| } |
| |
| return true; |
| } |
| |
| static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as, |
| char **error) |
| { |
| int r; |
| sector_t metadata_dev_size; |
| char b[BDEVNAME_SIZE]; |
| |
| if (!at_least_one_arg(as, error)) |
| return -EINVAL; |
| |
| r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, |
| &ca->metadata_dev); |
| if (r) { |
| *error = "Error opening metadata device"; |
| return r; |
| } |
| |
| metadata_dev_size = get_dev_size(ca->metadata_dev); |
| if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING) |
| DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", |
| bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS); |
| |
| return 0; |
| } |
| |
| static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as, |
| char **error) |
| { |
| int r; |
| |
| if (!at_least_one_arg(as, error)) |
| return -EINVAL; |
| |
| r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, |
| &ca->cache_dev); |
| if (r) { |
| *error = "Error opening cache device"; |
| return r; |
| } |
| ca->cache_sectors = get_dev_size(ca->cache_dev); |
| |
| return 0; |
| } |
| |
| static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, |
| char **error) |
| { |
| int r; |
| |
| if (!at_least_one_arg(as, error)) |
| return -EINVAL; |
| |
| r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE, |
| &ca->origin_dev); |
| if (r) { |
| *error = "Error opening origin device"; |
| return r; |
| } |
| |
| ca->origin_sectors = get_dev_size(ca->origin_dev); |
| if (ca->ti->len > ca->origin_sectors) { |
| *error = "Device size larger than cached device"; |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, |
| char **error) |
| { |
| unsigned long block_size; |
| |
| if (!at_least_one_arg(as, error)) |
| return -EINVAL; |
| |
| if (kstrtoul(dm_shift_arg(as), 10, &block_size) || !block_size || |
| block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || |
| block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || |
| block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { |
| *error = "Invalid data block size"; |
| return -EINVAL; |
| } |
| |
| if (block_size > ca->cache_sectors) { |
| *error = "Data block size is larger than the cache device"; |
| return -EINVAL; |
| } |
| |
| ca->block_size = block_size; |
| |
| return 0; |
| } |
| |
| static void init_features(struct cache_features *cf) |
| { |
| cf->mode = CM_WRITE; |
| cf->io_mode = CM_IO_WRITEBACK; |
| cf->metadata_version = 1; |
| } |
| |
| static int parse_features(struct cache_args *ca, struct dm_arg_set *as, |
| char **error) |
| { |
| static const struct dm_arg _args[] = { |
| {0, 2, "Invalid number of cache feature arguments"}, |
| }; |
| |
| int r; |
| unsigned argc; |
| const char *arg; |
| struct cache_features *cf = &ca->features; |
| |
| init_features(cf); |
| |
| r = dm_read_arg_group(_args, as, &argc, error); |
| if (r) |
| return -EINVAL; |
| |
| while (argc--) { |
| arg = dm_shift_arg(as); |
| |
| if (!strcasecmp(arg, "writeback")) |
| cf->io_mode = CM_IO_WRITEBACK; |
| |
| else if (!strcasecmp(arg, "writethrough")) |
| cf->io_mode = CM_IO_WRITETHROUGH; |
| |
| else if (!strcasecmp(arg, "passthrough")) |
| cf->io_mode = CM_IO_PASSTHROUGH; |
| |
| else if (!strcasecmp(arg, "metadata2")) |
| cf->metadata_version = 2; |
| |
| else { |
| *error = "Unrecognised cache feature requested"; |
| return -EINVAL; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int parse_policy(struct cache_args *ca, struct dm_arg_set *as, |
| char **error) |
| { |
| static const struct dm_arg _args[] = { |
| {0, 1024, "Invalid number of policy arguments"}, |
| }; |
| |
| int r; |
| |
| if (!at_least_one_arg(as, error)) |
| return -EINVAL; |
| |
| ca->policy_name = dm_shift_arg(as); |
| |
| r = dm_read_arg_group(_args, as, &ca->policy_argc, error); |
| if (r) |
| return -EINVAL; |
| |
| ca->policy_argv = (const char **)as->argv; |
| dm_consume_args(as, ca->policy_argc); |
| |
| return 0; |
| } |
| |
| static int parse_cache_args(struct cache_args *ca, int argc, char **argv, |
| char **error) |
| { |
| int r; |
| struct dm_arg_set as; |
| |
| as.argc = argc; |
| as.argv = argv; |
| |
| r = parse_metadata_dev(ca, &as, error); |
| if (r) |
| return r; |
| |
| r = parse_cache_dev(ca, &as, error); |
| if (r) |
| return r; |
| |
| r = parse_origin_dev(ca, &as, error); |
| if (r) |
| return r; |
| |
| r = parse_block_size(ca, &as, error); |
| if (r) |
| return r; |
| |
| r = parse_features(ca, &as, error); |
| if (r) |
| return r; |
| |
| r = parse_policy(ca, &as, error); |
| if (r) |
| return r; |
| |
| return 0; |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static struct kmem_cache *migration_cache; |
| |
| #define NOT_CORE_OPTION 1 |
| |
| static int process_config_option(struct cache *cache, const char *key, const char *value) |
| { |
| unsigned long tmp; |
| |
| if (!strcasecmp(key, "migration_threshold")) { |
| if (kstrtoul(value, 10, &tmp)) |
| return -EINVAL; |
| |
| cache->migration_threshold = tmp; |
| return 0; |
| } |
| |
| return NOT_CORE_OPTION; |
| } |
| |
| static int set_config_value(struct cache *cache, const char *key, const char *value) |
| { |
| int r = process_config_option(cache, key, value); |
| |
| if (r == NOT_CORE_OPTION) |
| r = policy_set_config_value(cache->policy, key, value); |
| |
| if (r) |
| DMWARN("bad config value for %s: %s", key, value); |
| |
| return r; |
| } |
| |
| static int set_config_values(struct cache *cache, int argc, const char **argv) |
| { |
| int r = 0; |
| |
| if (argc & 1) { |
| DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs."); |
| return -EINVAL; |
| } |
| |
| while (argc) { |
| r = set_config_value(cache, argv[0], argv[1]); |
| if (r) |
| break; |
| |
| argc -= 2; |
| argv += 2; |
| } |
| |
| return r; |
| } |
| |
| static int create_cache_policy(struct cache *cache, struct cache_args *ca, |
| char **error) |
| { |
| struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name, |
| cache->cache_size, |
| cache->origin_sectors, |
| cache->sectors_per_block); |
| if (IS_ERR(p)) { |
| *error = "Error creating cache's policy"; |
| return PTR_ERR(p); |
| } |
| cache->policy = p; |
| BUG_ON(!cache->policy); |
| |
| return 0; |
| } |
| |
| /* |
| * We want the discard block size to be at least the size of the cache |
| * block size and have no more than 2^14 discard blocks across the origin. |
| */ |
| #define MAX_DISCARD_BLOCKS (1 << 14) |
| |
| static bool too_many_discard_blocks(sector_t discard_block_size, |
| sector_t origin_size) |
| { |
| (void) sector_div(origin_size, discard_block_size); |
| |
| return origin_size > MAX_DISCARD_BLOCKS; |
| } |
| |
| static sector_t calculate_discard_block_size(sector_t cache_block_size, |
| sector_t origin_size) |
| { |
| sector_t discard_block_size = cache_block_size; |
| |
| if (origin_size) |
| while (too_many_discard_blocks(discard_block_size, origin_size)) |
| discard_block_size *= 2; |
| |
| return discard_block_size; |
| } |
| |
| static void set_cache_size(struct cache *cache, dm_cblock_t size) |
| { |
| dm_block_t nr_blocks = from_cblock(size); |
| |
| if (nr_blocks > (1 << 20) && cache->cache_size != size) |
| DMWARN_LIMIT("You have created a cache device with a lot of individual cache blocks (%llu)\n" |
| "All these mappings can consume a lot of kernel memory, and take some time to read/write.\n" |
| "Please consider increasing the cache block size to reduce the overall cache block count.", |
| (unsigned long long) nr_blocks); |
| |
| 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) |
| { |
| int r = 0; |
| char **error = &ca->ti->error; |
| struct cache *cache; |
| struct dm_target *ti = ca->ti; |
| dm_block_t origin_blocks; |
| struct dm_cache_metadata *cmd; |
| bool may_format = ca->features.mode == CM_WRITE; |
| |
| cache = kzalloc(sizeof(*cache), GFP_KERNEL); |
| if (!cache) |
| return -ENOMEM; |
| |
| cache->ti = ca->ti; |
| ti->private = cache; |
| ti->num_flush_bios = 2; |
| ti->flush_supported = true; |
| |
| ti->num_discard_bios = 1; |
| ti->discards_supported = true; |
| ti->split_discard_bios = false; |
| |
| cache->features = ca->features; |
| ti->per_io_data_size = get_per_bio_data_size(cache); |
| |
| cache->callbacks.congested_fn = cache_is_congested; |
| dm_table_add_target_callbacks(ti->table, &cache->callbacks); |
| |
| cache->metadata_dev = ca->metadata_dev; |
| cache->origin_dev = ca->origin_dev; |
| cache->cache_dev = ca->cache_dev; |
| |
| ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; |
| |
| origin_blocks = cache->origin_sectors = ca->origin_sectors; |
| origin_blocks = block_div(origin_blocks, ca->block_size); |
| cache->origin_blocks = to_oblock(origin_blocks); |
| |
| cache->sectors_per_block = ca->block_size; |
| if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) { |
| r = -EINVAL; |
| goto bad; |
| } |
| |
| if (ca->block_size & (ca->block_size - 1)) { |
| dm_block_t cache_size = ca->cache_sectors; |
| |
| cache->sectors_per_block_shift = -1; |
| cache_size = block_div(cache_size, ca->block_size); |
| set_cache_size(cache, to_cblock(cache_size)); |
| } else { |
| cache->sectors_per_block_shift = __ffs(ca->block_size); |
| set_cache_size(cache, to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift)); |
| } |
| |
| r = create_cache_policy(cache, ca, error); |
| if (r) |
| goto bad; |
| |
| cache->policy_nr_args = ca->policy_argc; |
| cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD; |
| |
| r = set_config_values(cache, ca->policy_argc, ca->policy_argv); |
| if (r) { |
| *error = "Error setting cache policy's config values"; |
| goto bad; |
| } |
| |
| cmd = dm_cache_metadata_open(cache->metadata_dev->bdev, |
| ca->block_size, may_format, |
| dm_cache_policy_get_hint_size(cache->policy), |
| ca->features.metadata_version); |
| if (IS_ERR(cmd)) { |
| *error = "Error creating metadata object"; |
| r = PTR_ERR(cmd); |
| goto bad; |
| } |
| cache->cmd = cmd; |
| set_cache_mode(cache, CM_WRITE); |
| if (get_cache_mode(cache) != CM_WRITE) { |
| *error = "Unable to get write access to metadata, please check/repair metadata."; |
| r = -EINVAL; |
| goto bad; |
| } |
| |
| if (passthrough_mode(&cache->features)) { |
| bool all_clean; |
| |
| r = dm_cache_metadata_all_clean(cache->cmd, &all_clean); |
| if (r) { |
| *error = "dm_cache_metadata_all_clean() failed"; |
| goto bad; |
| } |
| |
| if (!all_clean) { |
| *error = "Cannot enter passthrough mode unless all blocks are clean"; |
| 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_writethrough_bios); |
| atomic_set(&cache->nr_allocated_migrations, 0); |
| atomic_set(&cache->nr_io_migrations, 0); |
| init_waitqueue_head(&cache->migration_wait); |
| |
| r = -ENOMEM; |
| atomic_set(&cache->nr_dirty, 0); |
| cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size)); |
| if (!cache->dirty_bitset) { |
| *error = "could not allocate dirty bitset"; |
| goto bad; |
| } |
| clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size)); |
| |
| cache->discard_block_size = |
| calculate_discard_block_size(cache->sectors_per_block, |
| cache->origin_sectors); |
| cache->discard_nr_blocks = to_dblock(dm_sector_div_up(cache->origin_sectors, |
| cache->discard_block_size)); |
| cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks)); |
| if (!cache->discard_bitset) { |
| *error = "could not allocate discard bitset"; |
| goto bad; |
| } |
| clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); |
| |
| cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); |
| if (IS_ERR(cache->copier)) { |
| *error = "could not create kcopyd client"; |
| r = PTR_ERR(cache->copier); |
| goto bad; |
| } |
| |
| 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->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->prison = dm_bio_prison_create_v2(cache->wq); |
| if (!cache->prison) { |
| *error = "could not create bio prison"; |
| goto bad; |
| } |
| |
| cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE, |
| migration_cache); |
| if (!cache->migration_pool) { |
| *error = "Error creating cache's migration mempool"; |
| goto bad; |
| } |
| |
| cache->need_tick_bio = true; |
| cache->sized = false; |
| cache->invalidate = false; |
| cache->commit_requested = false; |
| cache->loaded_mappings = false; |
| cache->loaded_discards = false; |
| |
| load_stats(cache); |
| |
| atomic_set(&cache->stats.demotion, 0); |
| atomic_set(&cache->stats.promotion, 0); |
| atomic_set(&cache->stats.copies_avoided, 0); |
| atomic_set(&cache->stats.cache_cell_clash, 0); |
| atomic_set(&cache->stats.commit_count, 0); |
| atomic_set(&cache->stats.discard_count, 0); |
| |
| 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->tracker); |
| |
| init_rwsem(&cache->background_work_lock); |
| prevent_background_work(cache); |
| |
| *result = cache; |
| return 0; |
| bad: |
| destroy(cache); |
| return r; |
| } |
| |
| static int copy_ctr_args(struct cache *cache, int argc, const char **argv) |
| { |
| unsigned i; |
| const char **copy; |
| |
| copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL); |
| if (!copy) |
| return -ENOMEM; |
| for (i = 0; i < argc; i++) { |
| copy[i] = kstrdup(argv[i], GFP_KERNEL); |
| if (!copy[i]) { |
| while (i--) |
| kfree(copy[i]); |
| kfree(copy); |
| return -ENOMEM; |
| } |
| } |
| |
| cache->nr_ctr_args = argc; |
| cache->ctr_args = copy; |
| |
| return 0; |
| } |
| |
| static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv) |
| { |
| int r = -EINVAL; |
| struct cache_args *ca; |
| struct cache *cache = NULL; |
| |
| ca = kzalloc(sizeof(*ca), GFP_KERNEL); |
| if (!ca) { |
| ti->error = "Error allocating memory for cache"; |
| return -ENOMEM; |
| } |
| ca->ti = ti; |
| |
| r = parse_cache_args(ca, argc, argv, &ti->error); |
| if (r) |
| goto out; |
| |
| r = cache_create(ca, &cache); |
| if (r) |
| goto out; |
| |
| r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3); |
| if (r) { |
| destroy(cache); |
| goto out; |
| } |
| |
| ti->private = cache; |
| out: |
| destroy_cache_args(ca); |
| return r; |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static int cache_map(struct dm_target *ti, struct bio *bio) |
| { |
| struct cache *cache = ti->private; |
| |
| int r; |
| bool commit_needed; |
| dm_oblock_t block = get_bio_block(cache, bio); |
| size_t pb_data_size = get_per_bio_data_size(cache); |
| |
| 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 |
| * the end of the origin device. We don't cache these. |
| * Just remap to the origin and carry on. |
| */ |
| remap_to_origin(cache, bio); |
| accounted_begin(cache, bio); |
| return DM_MAPIO_REMAPPED; |
| } |
| |
| if (discard_or_flush(bio)) { |
| defer_bio(cache, bio); |
| return DM_MAPIO_SUBMITTED; |
| } |
| |
| r = map_bio(cache, bio, block, &commit_needed); |
| if (commit_needed) |
| schedule_commit(&cache->committer); |
| |
| return r; |
| } |
| |
| static int cache_end_io(struct dm_target *ti, struct bio *bio, |
| blk_status_t *error) |
| { |
| struct cache *cache = ti->private; |
| unsigned long flags; |
| 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->tick) { |
| policy_tick(cache->policy, false); |
| |
| spin_lock_irqsave(&cache->lock, flags); |
| cache->need_tick_bio = true; |
| spin_unlock_irqrestore(&cache->lock, flags); |
| } |
| |
| bio_drop_shared_lock(cache, bio); |
| accounted_complete(cache, bio); |
| |
| return DM_ENDIO_DONE; |
| } |
| |
| static int write_dirty_bitset(struct cache *cache) |
| { |
| int r; |
| |
| if (get_cache_mode(cache) >= CM_READ_ONLY) |
| return -EINVAL; |
| |
| r = dm_cache_set_dirty_bits(cache->cmd, from_cblock(cache->cache_size), cache->dirty_bitset); |
| if (r) |
| metadata_operation_failed(cache, "dm_cache_set_dirty_bits", r); |
| |
| return r; |
| } |
| |
| static int write_discard_bitset(struct cache *cache) |
| { |
| unsigned i, r; |
| |
| if (get_cache_mode(cache) >= CM_READ_ONLY) |
| return -EINVAL; |
| |
| r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size, |
| cache->discard_nr_blocks); |
| if (r) { |
| DMERR("%s: could not resize on-disk discard bitset", cache_device_name(cache)); |
| metadata_operation_failed(cache, "dm_cache_discard_bitset_resize", r); |
| return r; |
| } |
| |
| for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) { |
| r = dm_cache_set_discard(cache->cmd, to_dblock(i), |
| is_discarded(cache, to_dblock(i))); |
| if (r) { |
| metadata_operation_failed(cache, "dm_cache_set_discard", r); |
| return r; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int write_hints(struct cache *cache) |
| { |
| int r; |
| |
| if (get_cache_mode(cache) >= CM_READ_ONLY) |
| return -EINVAL; |
| |
| r = dm_cache_write_hints(cache->cmd, cache->policy); |
| if (r) { |
| metadata_operation_failed(cache, "dm_cache_write_hints", r); |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * returns true on success |
| */ |
| static bool sync_metadata(struct cache *cache) |
| { |
| int r1, r2, r3, r4; |
| |
| r1 = write_dirty_bitset(cache); |
| if (r1) |
| DMERR("%s: could not write dirty bitset", cache_device_name(cache)); |
| |
| r2 = write_discard_bitset(cache); |
| if (r2) |
| DMERR("%s: could not write discard bitset", cache_device_name(cache)); |
| |
| save_stats(cache); |
| |
| r3 = write_hints(cache); |
| if (r3) |
| DMERR("%s: could not write hints", cache_device_name(cache)); |
| |
| /* |
| * If writing the above metadata failed, we still commit, but don't |
| * set the clean shutdown flag. This will effectively force every |
| * dirty bit to be set on reload. |
| */ |
| r4 = commit(cache, !r1 && !r2 && !r3); |
| if (r4) |
| DMERR("%s: could not write cache metadata", cache_device_name(cache)); |
| |
| return !r1 && !r2 && !r3 && !r4; |
| } |
| |
| static void cache_postsuspend(struct dm_target *ti) |
| { |
| struct cache *cache = ti->private; |
| |
| prevent_background_work(cache); |
| BUG_ON(atomic_read(&cache->nr_io_migrations)); |
| |
| cancel_delayed_work(&cache->waker); |
| flush_workqueue(cache->wq); |
| WARN_ON(cache->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); |
| |
| if (get_cache_mode(cache) == CM_WRITE) |
| (void) sync_metadata(cache); |
| } |
| |
| static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, |
| bool dirty, uint32_t hint, bool hint_valid) |
| { |
| int r; |
| struct cache *cache = context; |
| |
| if (dirty) { |
| set_bit(from_cblock(cblock), cache->dirty_bitset); |
| atomic_inc(&cache->nr_dirty); |
| } else |
| clear_bit(from_cblock(cblock), cache->dirty_bitset); |
| |
| r = policy_load_mapping(cache->policy, oblock, cblock, dirty, hint, hint_valid); |
| if (r) |
| return r; |
| |
| return 0; |
| } |
| |
| /* |
| * The discard block size in the on disk metadata is not |
| * neccessarily the same as we're currently using. So we have to |
| * be careful to only set the discarded attribute if we know it |
| * covers a complete block of the new size. |
| */ |
| struct discard_load_info { |
| struct cache *cache; |
| |
| /* |
| * These blocks are sized using the on disk dblock size, rather |
| * than the current one. |
| */ |
| dm_block_t block_size; |
| dm_block_t discard_begin, discard_end; |
| }; |
| |
| static void discard_load_info_init(struct cache *cache, |
| struct discard_load_info *li) |
| { |
| li->cache = cache; |
| li->discard_begin = li->discard_end = 0; |
| } |
| |
| static void set_discard_range(struct discard_load_info *li) |
| { |
| sector_t b, e; |
| |
| if (li->discard_begin == li->discard_end) |
| return; |
| |
| /* |
| * Convert to sectors. |
| */ |
| b = li->discard_begin * li->block_size; |
| e = li->discard_end * li->block_size; |
| |
| /* |
| * Then convert back to the current dblock size. |
| */ |
| b = dm_sector_div_up(b, li->cache->discard_block_size); |
| sector_div(e, li->cache->discard_block_size); |
| |
| /* |
| * The origin may have shrunk, so we need to check we're still in |
| * bounds. |
| */ |
| if (e > from_dblock(li->cache->discard_nr_blocks)) |
| e = from_dblock(li->cache->discard_nr_blocks); |
| |
| for (; b < e; b++) |
| set_discard(li->cache, to_dblock(b)); |
| } |
| |
| static int load_discard(void *context, sector_t discard_block_size, |
| dm_dblock_t dblock, bool discard) |
| { |
| struct discard_load_info *li = context; |
| |
| li->block_size = discard_block_size; |
| |
| if (discard) { |
| if (from_dblock(dblock) == li->discard_end) |
| /* |
| * We're already in a discard range, just extend it. |
| */ |
| li->discard_end = li->discard_end + 1ULL; |
| |
| else { |
| /* |
| * Emit the old range and start a new one. |
| */ |
| set_discard_range(li); |
| li->discard_begin = from_dblock(dblock); |
| li->discard_end = li->discard_begin + 1ULL; |
| } |
| } else { |
| set_discard_range(li); |
| li->discard_begin = li->discard_end = 0; |
| } |
| |
| return 0; |
| } |
| |
| static dm_cblock_t get_cache_dev_size(struct cache *cache) |
| { |
| sector_t size = get_dev_size(cache->cache_dev); |
| (void) sector_div(size, cache->sectors_per_block); |
| return to_cblock(size); |
| } |
| |
| static bool can_resize(struct cache *cache, dm_cblock_t new_size) |
| { |
| if (from_cblock(new_size) > from_cblock(cache->cache_size)) |
| return true; |
| |
| /* |
| * We can't drop a dirty block when shrinking the cache. |
| */ |
| while (from_cblock(new_size) < from_cblock(cache->cache_size)) { |
| new_size = to_cblock(from_cblock(new_size) + 1); |
| if (is_dirty(cache, new_size)) { |
| DMERR("%s: unable to shrink cache; cache block %llu is dirty", |
| cache_device_name(cache), |
| (unsigned long long) from_cblock(new_size)); |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size) |
| { |
| int r; |
| |
| r = dm_cache_resize(cache->cmd, new_size); |
| if (r) { |
| DMERR("%s: could not resize cache metadata", cache_device_name(cache)); |
| metadata_operation_failed(cache, "dm_cache_resize", r); |
| return r; |
| } |
| |
| set_cache_size(cache, new_size); |
| |
| return 0; |
| } |
| |
| static int cache_preresume(struct dm_target *ti) |
| { |
| int r = 0; |
| struct cache *cache = ti->private; |
| dm_cblock_t csize = get_cache_dev_size(cache); |
| |
| /* |
| * Check to see if the cache has resized. |
| */ |
| if (!cache->sized) { |
| r = resize_cache_dev(cache, csize); |
| if (r) |
| return r; |
| |
| cache->sized = true; |
| |
| } else if (csize != cache->cache_size) { |
| if (!can_resize(cache, csize)) |
| return -EINVAL; |
| |
| r = resize_cache_dev(cache, csize); |
| if (r) |
| return r; |
| } |
| |
| if (!cache->loaded_mappings) { |
| r = dm_cache_load_mappings(cache->cmd, cache->policy, |
| load_mapping, cache); |
| if (r) { |
| DMERR("%s: could not load cache mappings", cache_device_name(cache)); |
| metadata_operation_failed(cache, "dm_cache_load_mappings", r); |
| return r; |
| } |
| |
| cache->loaded_mappings = true; |
| } |
| |
| if (!cache->loaded_discards) { |
| struct discard_load_info li; |
| |
| /* |
| * The discard bitset could have been resized, or the |
| * discard block size changed. To be safe we start by |
| * setting every dblock to not discarded. |
| */ |
| clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks)); |
| |
| discard_load_info_init(cache, &li); |
| r = dm_cache_load_discards(cache->cmd, load_discard, &li); |
| if (r) { |
| DMERR("%s: could not load origin discards", cache_device_name(cache)); |
| metadata_operation_failed(cache, "dm_cache_load_discards", r); |
| return r; |
| } |
| set_discard_range(&li); |
| |
| cache->loaded_discards = true; |
| } |
| |
| return r; |
| } |
| |
| 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); |
| } |
| |
| /* |
| * Status format: |
|