diff options
| -rw-r--r-- | drivers/md/dm-cache-target.c | 138 |
1 files changed, 88 insertions, 50 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 79ac8603644d..ff267db60025 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -142,6 +142,7 @@ struct cache { spinlock_t lock; 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; @@ -199,6 +200,11 @@ struct per_bio_data { bool tick:1; unsigned req_nr:2; struct dm_deferred_entry *all_io_entry; + + /* writethrough fields */ + struct cache *cache; + dm_cblock_t cblock; + bio_end_io_t *saved_bi_end_io; }; struct dm_cache_migration { @@ -616,6 +622,56 @@ static void issue(struct cache *cache, struct bio *bio) spin_unlock_irqrestore(&cache->lock, flags); } +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_worker(cache); +} + +static void writethrough_endio(struct bio *bio, int err) +{ + struct per_bio_data *pb = get_per_bio_data(bio); + bio->bi_end_io = pb->saved_bi_end_io; + + if (err) { + bio_endio(bio, err); + return; + } + + remap_to_cache(pb->cache, bio, pb->cblock); + + /* + * We can't issue this bio directly, since we're in interrupt + * context. So it get's put on a bio list for processing by the + * worker thread. + */ + defer_writethrough_bio(pb->cache, bio); +} + +/* + * 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->cache = cache; + pb->cblock = cblock; + pb->saved_bi_end_io = bio->bi_end_io; + bio->bi_end_io = writethrough_endio; + + remap_to_origin_clear_discard(pb->cache, bio, oblock); +} + /*---------------------------------------------------------------- * Migration processing * @@ -1077,14 +1133,9 @@ static void process_bio(struct cache *cache, struct prealloc *structs, inc_hit_counter(cache, bio); pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); - if (is_writethrough_io(cache, bio, lookup_result.cblock)) { - /* - * No need to mark anything dirty in write through mode. - */ - pb->req_nr == 0 ? - remap_to_cache(cache, bio, lookup_result.cblock) : - remap_to_origin_clear_discard(cache, bio, block); - } else + if (is_writethrough_io(cache, bio, lookup_result.cblock)) + remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); + else remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); issue(cache, bio); @@ -1093,17 +1144,8 @@ static void process_bio(struct cache *cache, struct prealloc *structs, case POLICY_MISS: inc_miss_counter(cache, bio); pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); - - 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, 0); - } else { - remap_to_origin_clear_discard(cache, bio, block); - issue(cache, bio); - } + remap_to_origin_clear_discard(cache, bio, block); + issue(cache, bio); break; case POLICY_NEW: @@ -1224,6 +1266,23 @@ static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) submit_bios ? generic_make_request(bio) : bio_io_error(bio); } +static void process_deferred_writethrough_bios(struct cache *cache) +{ + 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); + + while ((bio = bio_list_pop(&bios))) + generic_make_request(bio); +} + static void writeback_some_dirty_blocks(struct cache *cache) { int r = 0; @@ -1320,6 +1379,7 @@ static int more_work(struct cache *cache) else return !bio_list_empty(&cache->deferred_bios) || !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); @@ -1338,6 +1398,8 @@ static void do_worker(struct work_struct *ws) writeback_some_dirty_blocks(cache); + process_deferred_writethrough_bios(cache); + if (commit_if_needed(cache)) { process_deferred_flush_bios(cache, false); @@ -1803,8 +1865,6 @@ static sector_t calculate_discard_block_size(sector_t cache_block_size, #define DEFAULT_MIGRATION_THRESHOLD (2048 * 100) -static unsigned cache_num_write_bios(struct dm_target *ti, struct bio *bio); - static int cache_create(struct cache_args *ca, struct cache **result) { int r = 0; @@ -1831,9 +1891,6 @@ static int cache_create(struct cache_args *ca, struct cache **result) memcpy(&cache->features, &ca->features, sizeof(cache->features)); - if (cache->features.write_through) - ti->num_write_bios = cache_num_write_bios; - cache->callbacks.congested_fn = cache_is_congested; dm_table_add_target_callbacks(ti->table, &cache->callbacks); @@ -1883,6 +1940,7 @@ static int cache_create(struct cache_args *ca, struct cache **result) spin_lock_init(&cache->lock); 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); @@ -2028,20 +2086,6 @@ out: return r; } -static unsigned cache_num_write_bios(struct dm_target *ti, struct bio *bio) -{ - int r; - struct cache *cache = ti->private; - dm_oblock_t block = get_bio_block(cache, bio); - dm_cblock_t cblock; - - r = policy_lookup(cache->policy, block, &cblock); - if (r < 0) - return 2; /* assume the worst */ - - return (!r && !is_dirty(cache, cblock)) ? 2 : 1; -} - static int cache_map(struct dm_target *ti, struct bio *bio) { struct cache *cache = ti->private; @@ -2109,18 +2153,12 @@ static int cache_map(struct dm_target *ti, struct bio *bio) inc_hit_counter(cache, bio); pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); - if (is_writethrough_io(cache, bio, lookup_result.cblock)) { - /* - * No need to mark anything dirty in write through mode. - */ - pb->req_nr == 0 ? - remap_to_cache(cache, bio, lookup_result.cblock) : - remap_to_origin_clear_discard(cache, bio, block); - cell_defer(cache, cell, false); - } else { + if (is_writethrough_io(cache, bio, lookup_result.cblock)) + remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); + else remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); - cell_defer(cache, cell, false); - } + + cell_defer(cache, cell, false); break; case POLICY_MISS: @@ -2547,7 +2585,7 @@ static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) static struct target_type cache_target = { .name = "cache", - .version = {1, 0, 0}, + .version = {1, 1, 0}, .module = THIS_MODULE, .ctr = cache_ctr, .dtr = cache_dtr, |