diff options
Diffstat (limited to 'drivers/md/dm-cache-target.c')
| -rw-r--r-- | drivers/md/dm-cache-target.c | 886 |
1 files changed, 664 insertions, 222 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 29569768ffb..2c63326638b 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -61,6 +61,40 @@ static void free_bitset(unsigned long *bits) /*----------------------------------------------------------------*/ +/* + * 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; + void *bi_private; +}; + +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; + h->bi_private = bio->bi_private; + + 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; + bio->bi_private = h->bi_private; + + /* + * Must bump bi_remaining to allow bio to complete with + * restored bi_end_io. + */ + atomic_inc(&bio->bi_remaining); +} + +/*----------------------------------------------------------------*/ + #define PRISON_CELLS 1024 #define MIGRATION_POOL_SIZE 128 #define COMMIT_PERIOD HZ @@ -76,14 +110,37 @@ static void free_bitset(unsigned long *bits) /* * FIXME: the cache is read/write for the time being. */ -enum cache_mode { +enum cache_metadata_mode { CM_WRITE, /* metadata may be changed */ CM_READ_ONLY, /* metadata may not be changed */ }; +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_mode mode; - bool write_through:1; + enum cache_metadata_mode mode; + enum cache_io_mode io_mode; }; struct cache_stats { @@ -99,6 +156,25 @@ struct cache_stats { atomic_t discard_count; }; +/* + * Defines a range of cblocks, begin to (end - 1) are in the range. end is + * the one-past-the-end value. + */ +struct cblock_range { + dm_cblock_t begin; + dm_cblock_t end; +}; + +struct invalidation_request { + struct list_head list; + struct cblock_range *cblocks; + + atomic_t complete; + int err; + + wait_queue_head_t result_wait; +}; + struct cache { struct dm_target *ti; struct dm_target_callbacks callbacks; @@ -148,18 +224,21 @@ struct cache { wait_queue_head_t migration_wait; atomic_t nr_migrations; + wait_queue_head_t quiescing_wait; + atomic_t quiescing; + atomic_t quiescing_ack; + /* * cache_size entries, dirty if set */ - dm_cblock_t nr_dirty; + atomic_t nr_dirty; unsigned long *dirty_bitset; /* * origin_blocks entries, discarded if set. */ - dm_dblock_t discard_nr_blocks; + dm_oblock_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 @@ -186,7 +265,7 @@ struct cache { bool need_tick_bio:1; bool sized:1; - bool quiescing:1; + bool invalidate:1; bool commit_requested:1; bool loaded_mappings:1; bool loaded_discards:1; @@ -197,12 +276,19 @@ struct cache { struct cache_features features; struct cache_stats stats; + + /* + * Invalidation fields. + */ + spinlock_t invalidation_lock; + struct list_head invalidation_requests; }; struct per_bio_data { bool tick:1; unsigned req_nr:2; struct dm_deferred_entry *all_io_entry; + struct dm_hook_info hook_info; /* * writethrough fields. These MUST remain at the end of this @@ -211,7 +297,6 @@ struct per_bio_data { */ struct cache *cache; dm_cblock_t cblock; - bio_end_io_t *saved_bi_end_io; struct dm_bio_details bio_details; }; @@ -228,6 +313,8 @@ struct dm_cache_migration { bool writeback:1; bool demote:1; bool promote:1; + bool requeue_holder:1; + bool invalidate:1; struct dm_bio_prison_cell *old_ocell; struct dm_bio_prison_cell *new_ocell; @@ -405,7 +492,7 @@ static bool is_dirty(struct cache *cache, dm_cblock_t b) static void set_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cblock) { if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) { - cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) + 1); + atomic_inc(&cache->nr_dirty); policy_set_dirty(cache->policy, oblock); } } @@ -414,8 +501,7 @@ static void clear_dirty(struct cache *cache, dm_oblock_t oblock, dm_cblock_t cbl { if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) { policy_clear_dirty(cache->policy, oblock); - cache->nr_dirty = to_cblock(from_cblock(cache->nr_dirty) - 1); - if (!from_cblock(cache->nr_dirty)) + if (atomic_dec_return(&cache->nr_dirty) == 0) dm_table_event(cache->ti->table); } } @@ -438,48 +524,33 @@ static dm_block_t block_div(dm_block_t b, uint32_t n) return b; } -static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) -{ - uint32_t discard_blocks = cache->discard_block_size; - dm_block_t b = from_oblock(oblock); - - if (!block_size_is_power_of_two(cache)) - discard_blocks = discard_blocks / cache->sectors_per_block; - else - discard_blocks >>= cache->sectors_per_block_shift; - - b = block_div(b, discard_blocks); - - return to_dblock(b); -} - -static void set_discard(struct cache *cache, dm_dblock_t b) +static void set_discard(struct cache *cache, dm_oblock_t b) { unsigned long flags; atomic_inc(&cache->stats.discard_count); spin_lock_irqsave(&cache->lock, flags); - set_bit(from_dblock(b), cache->discard_bitset); + set_bit(from_oblock(b), cache->discard_bitset); spin_unlock_irqrestore(&cache->lock, flags); } -static void clear_discard(struct cache *cache, dm_dblock_t b) +static void clear_discard(struct cache *cache, dm_oblock_t b) { unsigned long flags; spin_lock_irqsave(&cache->lock, flags); - clear_bit(from_dblock(b), cache->discard_bitset); + clear_bit(from_oblock(b), cache->discard_bitset); spin_unlock_irqrestore(&cache->lock, flags); } -static bool is_discarded(struct cache *cache, dm_dblock_t b) +static bool is_discarded(struct cache *cache, dm_oblock_t b) { int r; unsigned long flags; spin_lock_irqsave(&cache->lock, flags); - r = test_bit(from_dblock(b), cache->discard_bitset); + r = test_bit(from_oblock(b), cache->discard_bitset); spin_unlock_irqrestore(&cache->lock, flags); return r; @@ -491,8 +562,7 @@ static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) unsigned long flags; spin_lock_irqsave(&cache->lock, flags); - r = test_bit(from_dblock(oblock_to_dblock(cache, b)), - cache->discard_bitset); + r = test_bit(from_oblock(b), cache->discard_bitset); spin_unlock_irqrestore(&cache->lock, flags); return r; @@ -533,9 +603,24 @@ static void save_stats(struct cache *cache) #define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) #define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) +static bool writethrough_mode(struct cache_features *f) +{ + return f->io_mode == CM_IO_WRITETHROUGH; +} + +static bool writeback_mode(struct cache_features *f) +{ + return f->io_mode == CM_IO_WRITEBACK; +} + +static bool passthrough_mode(struct cache_features *f) +{ + return f->io_mode == CM_IO_PASSTHROUGH; +} + static size_t get_per_bio_data_size(struct cache *cache) { - return cache->features.write_through ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; + 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) @@ -567,15 +652,18 @@ static void remap_to_origin(struct cache *cache, struct bio *bio) static void remap_to_cache(struct cache *cache, struct bio *bio, dm_cblock_t cblock) { - sector_t bi_sector = bio->bi_sector; + sector_t bi_sector = bio->bi_iter.bi_sector; + sector_t block = from_cblock(cblock); bio->bi_bdev = cache->cache_dev->bdev; if (!block_size_is_power_of_two(cache)) - bio->bi_sector = (from_cblock(cblock) * cache->sectors_per_block) + - sector_div(bi_sector, cache->sectors_per_block); + bio->bi_iter.bi_sector = + (block * cache->sectors_per_block) + + sector_div(bi_sector, cache->sectors_per_block); else - bio->bi_sector = (from_cblock(cblock) << cache->sectors_per_block_shift) | - (bi_sector & (cache->sectors_per_block - 1)); + 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) @@ -599,22 +687,23 @@ static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, 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)); + clear_discard(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, oblock, cblock); - clear_discard(cache, oblock_to_dblock(cache, oblock)); + clear_discard(cache, oblock); } } static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio) { - sector_t block_nr = bio->bi_sector; + 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); @@ -662,7 +751,8 @@ static void defer_writethrough_bio(struct cache *cache, struct bio *bio) static void writethrough_endio(struct bio *bio, int err) { struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); - bio->bi_end_io = pb->saved_bi_end_io; + + dm_unhook_bio(&pb->hook_info, bio); if (err) { bio_endio(bio, err); @@ -693,9 +783,8 @@ static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, pb->cache = cache; pb->cblock = cblock; - pb->saved_bi_end_io = bio->bi_end_io; + dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL); dm_bio_record(&pb->bio_details, bio); - bio->bi_end_io = writethrough_endio; remap_to_origin_clear_discard(pb->cache, bio, oblock); } @@ -748,8 +837,9 @@ static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, static void cleanup_migration(struct dm_cache_migration *mg) { - dec_nr_migrations(mg->cache); + struct cache *cache = mg->cache; free_migration(mg); + dec_nr_migrations(cache); } static void migration_failure(struct dm_cache_migration *mg) @@ -765,13 +855,13 @@ static void migration_failure(struct dm_cache_migration *mg) DMWARN_LIMIT("demotion failed; couldn't copy block"); policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); - cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1); + cell_defer(cache, mg->old_ocell, mg->promote ? false : true); if (mg->promote) - cell_defer(cache, mg->new_ocell, 1); + cell_defer(cache, mg->new_ocell, true); } else { DMWARN_LIMIT("promotion failed; couldn't copy block"); policy_remove_mapping(cache->policy, mg->new_oblock); - cell_defer(cache, mg->new_ocell, 1); + cell_defer(cache, mg->new_ocell, true); } cleanup_migration(mg); @@ -823,7 +913,7 @@ static void migration_success_post_commit(struct dm_cache_migration *mg) return; } else if (mg->demote) { - cell_defer(cache, mg->old_ocell, mg->promote ? 0 : 1); + cell_defer(cache, mg->old_ocell, mg->promote ? false : true); if (mg->promote) { mg->demote = false; @@ -832,11 +922,19 @@ static void migration_success_post_commit(struct dm_cache_migration *mg) list_add_tail(&mg->list, &cache->quiesced_migrations); spin_unlock_irqrestore(&cache->lock, flags); - } else + } else { + if (mg->invalidate) + policy_remove_mapping(cache->policy, mg->old_oblock); cleanup_migration(mg); + } } else { - cell_defer(cache, mg->new_ocell, true); + if (mg->requeue_holder) + cell_defer(cache, mg->new_ocell, true); + else { + bio_endio(mg->new_ocell->holder, 0); + cell_defer(cache, mg->new_ocell, false); + } clear_dirty(cache, mg->new_oblock, mg->cblock); cleanup_migration(mg); } @@ -863,12 +961,13 @@ static void issue_copy_real(struct dm_cache_migration *mg) int r; struct dm_io_region o_region, c_region; struct cache *cache = mg->cache; + sector_t cblock = from_cblock(mg->cblock); o_region.bdev = cache->origin_dev->bdev; o_region.count = cache->sectors_per_block; c_region.bdev = cache->cache_dev->bdev; - c_region.sector = from_cblock(mg->cblock) * cache->sectors_per_block; + c_region.sector = cblock * cache->sectors_per_block; c_region.count = cache->sectors_per_block; if (mg->writeback || mg->demote) { @@ -881,8 +980,48 @@ static void issue_copy_real(struct dm_cache_migration *mg) r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, mg); } - if (r < 0) + if (r < 0) { + DMERR_LIMIT("issuing migration failed"); migration_failure(mg); + } +} + +static void overwrite_endio(struct bio *bio, int err) +{ + 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); + unsigned long flags; + + dm_unhook_bio(&pb->hook_info, bio); + + if (err) + mg->err = true; + + mg->requeue_holder = false; + + spin_lock_irqsave(&cache->lock, flags); + list_add_tail(&mg->list, &cache->completed_migrations); + spin_unlock_irqrestore(&cache->lock, flags); + + wake_worker(cache); +} + +static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio) +{ + size_t pb_data_size = get_per_bio_data_size(mg->cache); + struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); + + dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg); + remap_to_cache_dirty(mg->cache, bio, mg->new_oblock, mg->cblock); + generic_make_request(bio); +} + +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 void avoid_copy(struct dm_cache_migration *mg) @@ -899,9 +1038,17 @@ static void issue_copy(struct dm_cache_migration *mg) if (mg->writeback || mg->demote) avoid = !is_dirty(cache, mg->cblock) || is_discarded_oblock(cache, mg->old_oblock); - else + else { + struct bio *bio = mg->new_ocell->holder; + avoid = is_discarded_oblock(cache, mg->new_oblock); + if (!avoid && bio_writes_complete_block(cache, bio)) { + issue_overwrite(mg, bio); + return; + } + } + avoid ? avoid_copy(mg) : issue_copy_real(mg); } @@ -991,6 +1138,8 @@ static void promote(struct cache *cache, struct prealloc *structs, mg->writeback = false; mg->demote = false; mg->promote = true; + mg->requeue_holder = true; + mg->invalidate = false; mg->cache = cache; mg->new_oblock = oblock; mg->cblock = cblock; @@ -1012,6 +1161,8 @@ static void writeback(struct cache *cache, struct prealloc *structs, mg->writeback = true; mg->demote = false; mg->promote = false; + mg->requeue_holder = true; + mg->invalidate = false; mg->cache = cache; mg->old_oblock = oblock; mg->cblock = cblock; @@ -1035,6 +1186,8 @@ static void demote_then_promote(struct cache *cache, struct prealloc *structs, mg->writeback = false; mg->demote = true; mg->promote = true; + mg->requeue_holder = true; + mg->invalidate = false; mg->cache = cache; mg->old_oblock = old_oblock; mg->new_oblock = new_oblock; @@ -1047,6 +1200,33 @@ static void demote_then_promote(struct cache *cache, struct prealloc *structs, quiesce_migration(mg); } +/* + * Invalidate a cache entry. No writeback occurs; any changes in the cache + * block are thrown away. + */ +static void invalidate(struct cache *cache, struct prealloc *structs, + dm_oblock_t oblock, dm_cblock_t cblock, + struct dm_bio_prison_cell *cell) +{ + struct dm_cache_migration *mg = prealloc_get_migration(structs); + + mg->err = false; + mg->writeback = false; + mg->demote = true; + mg->promote = false; + mg->requeue_holder = true; + mg->invalidate = true; + mg->cache = cache; + mg->old_oblock = oblock; + mg->cblock = cblock; + mg->old_ocell = cell; + mg->new_ocell = NULL; + mg->start_jiffies = jiffies; + + inc_nr_migrations(cache); + quiesce_migration(mg); +} + /*---------------------------------------------------------------- * bio processing *--------------------------------------------------------------*/ @@ -1066,7 +1246,7 @@ static void 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); - BUG_ON(bio->bi_size); + BUG_ON(bio->bi_iter.bi_size); if (!pb->req_nr) remap_to_origin(cache, bio); else @@ -1089,15 +1269,15 @@ static void process_flush_bio(struct cache *cache, struct bio *bio) */ static void process_discard_bio(struct cache *cache, struct bio *bio) { - dm_block_t start_block = dm_sector_div_up(bio->bi_sector, - cache->discard_block_size); - dm_block_t end_block = bio->bi_sector + bio_sectors(bio); + dm_block_t start_block = dm_sector_div_up(bio->bi_iter.bi_sector, + cache->sectors_per_block); + dm_block_t end_block = bio_end_sector(bio); dm_block_t b; - end_block = block_div(end_block, cache->discard_block_size); + end_block = block_div(end_block, cache->sectors_per_block); for (b = start_block; b < end_block; b++) - set_discard(cache, to_dblock(b)); + set_discard(cache, to_oblock(b)); bio_endio(bio, 0); } @@ -1109,13 +1289,6 @@ static bool spare_migration_bandwidth(struct cache *cache) return current_volume < cache->migration_threshold; } -static bool is_writethrough_io(struct cache *cache, struct bio *bio, - dm_cblock_t cblock) -{ - return bio_data_dir(bio) == WRITE && - cache->features.write_through && !is_dirty(cache, cblock); -} - static void inc_hit_counter(struct cache *cache, struct bio *bio) { atomic_inc(bio_data_dir(bio) == READ ? @@ -1128,6 +1301,15 @@ static void inc_miss_counter(struct cache *cache, struct bio *bio) &cache->stats.read_miss : &cache->stats.write_miss); } +static void issue_cache_bio(struct cache *cache, struct bio *bio, + struct per_bio_data *pb, + dm_oblock_t oblock, dm_cblock_t cblock) +{ + pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); + remap_to_cache_dirty(cache, bio, oblock, cblock); + issue(cache, bio); +} + static void process_bio(struct cache *cache, struct prealloc *structs, struct bio *bio) { @@ -1139,7 +1321,8 @@ static void process_bio(struct cache *cache, struct prealloc *structs, size_t pb_data_size = get_per_bio_data_size(cache); struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); bool discarded_block = is_discarded_oblock(cache, block); - bool can_migrate = discarded_block || spare_migration_bandwidth(cache); + bool passthrough = passthrough_mode(&cache->features); + bool can_migrate = !passthrough && (discarded_block || spare_migration_bandwidth(cache)); /* * Check to see if that block is currently migrating. @@ -1160,15 +1343,39 @@ static void process_bio(struct cache *cache, struct prealloc *structs, switch (lookup_result.op) { case POLICY_HIT: - inc_hit_counter(cache, bio); - pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); + if (passthrough) { + inc_miss_counter(cache, bio); - 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); + /* + * Passthrough always maps to the origin, + * invalidating any cache blocks that are written + * to. + */ + + if (bio_data_dir(bio) == WRITE) { + atomic_inc(&cache->stats.demotion); + invalidate(cache, structs, block, lookup_result.cblock, new_ocell); + release_cell = false; + + } else { + /* FIXME: factor out issue_origin() */ + pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); + remap_to_origin_clear_discard(cache, bio, block); + issue(cache, bio); + } + } else { + inc_hit_counter(cache, bio); + + if (bio_data_dir(bio) == WRITE && + writethrough_mode(&cache->features) && + !is_dirty(cache, lookup_result.cblock)) { + pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); + remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); + issue(cache, bio); + } else + issue_cache_bio(cache, bio, pb, block, lookup_result.cblock); + } - issue(cache, bio); break; case POLICY_MISS: @@ -1227,15 +1434,17 @@ static int need_commit_due_to_time(struct cache *cache) static int commit_if_needed(struct cache *cache) { - if (dm_cache_changed_this_transaction(cache->cmd) && - (cache->commit_requested || need_commit_due_to_time(cache))) { + int r = 0; + + if ((cache->commit_requested || need_commit_due_to_time(cache)) && + dm_cache_changed_this_transaction(cache->cmd)) { atomic_inc(&cache->stats.commit_count); - cache->last_commit_jiffies = jiffies; cache->commit_requested = false; - return dm_cache_commit(cache->cmd, false); + r = dm_cache_commit(cache->cmd, false); + cache->last_commit_jiffies = jiffies; } - return 0; + return r; } static void process_deferred_bios(struct cache *cache) @@ -1344,36 +1553,88 @@ static void writeback_some_dirty_blocks(struct cache *cache) } /*---------------------------------------------------------------- - * Main worker loop + * Invalidations. + * Dropping something from the cache *without* writing back. *--------------------------------------------------------------*/ -static void start_quiescing(struct cache *cache) + +static void process_invalidation_request(struct cache *cache, struct invalidation_request *req) { - unsigned long flags; + int r = 0; + uint64_t begin = from_cblock(req->cblocks->begin); + uint64_t end = from_cblock(req->cblocks->end); - spin_lock_irqsave(&cache->lock, flags); - cache->quiescing = 1; - spin_unlock_irqrestore(&cache->lock, flags); + while (begin != end) { + r = policy_remove_cblock(cache->policy, to_cblock(begin)); + if (!r) { + r = dm_cache_remove_mapping(cache->cmd, to_cblock(begin)); + if (r) + break; + + } else if (r == -ENODATA) { + /* harmless, already unmapped */ + r = 0; + + } else { + DMERR("policy_remove_cblock failed"); + break; + } + + begin++; + } + + cache->commit_requested = true; + + req->err = r; + atomic_set(&req->complete, 1); + + wake_up(&req->result_wait); } -static void stop_quiescing(struct cache *cache) +static void process_invalidation_requests(struct cache *cache) { - unsigned long flags; + struct list_head list; + struct invalidation_request *req, *tmp; - spin_lock_irqsave(&cache->lock, flags); - cache->quiescing = 0; - spin_unlock_irqrestore(&cache->lock, flags); + INIT_LIST_HEAD(&list); + spin_lock(&cache->invalidation_lock); + list_splice_init(&cache->invalidation_requests, &list); + spin_unlock(&cache->invalidation_lock); + + list_for_each_entry_safe (req, tmp, &list, list) + process_invalidation_request(cache, req); } +/*---------------------------------------------------------------- + * Main worker loop + *--------------------------------------------------------------*/ static bool is_quiescing(struct cache *cache) { - int r; - unsigned long flags; + return atomic_read(&cache->quiescing); +} - spin_lock_irqsave(&cache->lock, flags); - r = cache->quiescing; - spin_unlock_irqrestore(&cache->lock, flags); +static void ack_quiescing(struct cache *cache) +{ + if (is_quiescing(cache)) { + atomic_inc(&cache->quiescing_ack); + wake_up(&cache->quiescing_wait); + } +} - return r; +static void wait_for_quiescing_ack(struct cache *cache) +{ + wait_event(cache->quiescing_wait, atomic_read(&cache->quiescing_ack)); +} + +static void start_quiescing(struct cache *cache) +{ + atomic_inc(&cache->quiescing); + wait_for_quiescing_ack(cache); +} + +static void stop_quiescing(struct cache *cache) +{ + atomic_set(&cache->quiescing, 0); + atomic_set(&cache->quiescing_ack, 0); } static void wait_for_migrations(struct cache *cache) @@ -1412,7 +1673,8 @@ static int more_work(struct cache *cache) !bio_list_empty(&cache->deferred_writethrough_bios) || !list_empty(&cache->quiesced_migrations) || !list_empty(&cache->completed_migrations) || - !list_empty(&cache->need_commit_migrations); + !list_empty(&cache->need_commit_migrations) || + cache->invalidate; } static void do_worker(struct work_struct *ws) @@ -1420,16 +1682,16 @@ static void do_worker(struct work_struct *ws) struct cache *cache = container_of(ws, struct cache, worker); do { - if (!is_quiescing(cache)) + if (!is_quiescing(cache)) { + writeback_some_dirty_blocks(cache); + process_deferred_writethrough_bios(cache); process_deferred_bios(cache); + process_invalidation_requests(cache); + } process_migrations(cache, &cache->quiesced_migrations, issue_copy); process_migrations(cache, &cache->completed_migrations, complete_migration); - writeback_some_dirty_blocks(cache); - - process_deferred_writethrough_bios(cache); - if (commit_if_needed(cache)) { process_deferred_flush_bios(cache, false); @@ -1442,6 +1704,9 @@ static void do_worker(struct work_struct *ws) process_migrations(cache, &cache->need_commit_migrations, migration_success_post_commit); } + + ack_quiescing(cache); + } while (more_work(cache)); } @@ -1715,7 +1980,7 @@ static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as, static void init_features(struct cache_features *cf) { cf->mode = CM_WRITE; - cf->write_through = false; + cf->io_mode = CM_IO_WRITEBACK; } static int parse_features(struct cache_args *ca, struct dm_arg_set *as, @@ -1740,10 +2005,13 @@ static int parse_features(struct cache_args *ca, struct dm_arg_set *as, arg = dm_shift_arg(as); if (!strcasecmp(arg, "writeback")) - cf->write_through = false; + cf->io_mode = CM_IO_WRITEBACK; else if (!strcasecmp(arg, "writethrough")) - cf->write_through = true; + cf->io_mode = CM_IO_WRITETHROUGH; + + else if (!strcasecmp(arg, "passthrough")) + cf->io_mode = CM_IO_PASSTHROUGH; else { *error = "Unrecognised cache feature requested"; @@ -1872,47 +2140,19 @@ static int set_config_values(struct cache *cache, int argc, const char **argv) static int create_cache_policy(struct cache *cache, struct cache_args *ca, char **error) { - cache->policy = dm_cache_policy_create(ca->policy_name, - cache->cache_size, - cache->origin_sectors, - cache->sectors_per_block); - if (!cache->policy) { + 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 -ENOMEM; + return PTR_ERR(p); } + cache->policy = p; return 0; } -/* - * We want the discard block size to be a power of two, 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; - - discard_block_size = roundup_pow_of_two(cache_block_size); - - if (origin_size) - while (too_many_discard_blocks(discard_block_size, origin_size)) - discard_block_size *= 2; - - return discard_block_size; -} - #define DEFAULT_MIGRATION_THRESHOLD 2048 static int cache_create(struct cache_args *ca, struct cache **result) @@ -1937,6 +2177,8 @@ static int cache_create(struct cache_args *ca, struct cache **result) ti->num_discard_bios = 1; ti->discards_supported = true; ti->discard_zeroes_data_unsupported = true; + /* Discard bios must be split on a block boundary */ + ti->split_discard_bios = true; cache->features = ca->features; ti->per_bio_data_size = get_per_bio_data_size(cache); @@ -1995,6 +2237,22 @@ static int cache_create(struct cache_args *ca, struct cache **result) } cache->cmd = cmd; + 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; + } + } + spin_lock_init(&cache->lock); bio_list_init(&cache->deferred_bios); bio_list_init(&cache->deferred_flush_bios); @@ -2005,8 +2263,12 @@ static int cache_create(struct cache_args *ca, struct cache **result) atomic_set(&cache->nr_migrations, 0); init_waitqueue_head(&cache->migration_wait); + init_waitqueue_head(&cache->quiescing_wait); + atomic_set(&cache->quiescing, 0); + atomic_set(&cache->quiescing_ack, 0); + r = -ENOMEM; - cache->nr_dirty = 0; + 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"; @@ -2014,16 +2276,13 @@ static int cache_create(struct cache_args *ca, struct cache **result) } 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 = oblock_to_dblock(cache, cache->origin_blocks); - cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks)); + cache->discard_nr_blocks = cache->origin_blocks; + cache->discard_bitset = alloc_bitset(from_oblock(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)); + clear_bitset(cache->discard_bitset, from_oblock(cache->discard_nr_blocks)); cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); if (IS_ERR(cache->copier)) { @@ -2064,7 +2323,7 @@ static int cache_create(struct cache_args *ca, struct cache **result) cache->need_tick_bio = true; cache->sized = false; - cache->quiescing = false; + cache->invalidate = false; cache->commit_requested = false; cache->loaded_mappings = false; cache->loaded_discards = false; @@ -2078,6 +2337,9 @@ static int cache_create(struct cache_args *ca, struct cache **result) 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); + *result = cache; return 0; @@ -2155,20 +2417,18 @@ static int cache_map(struct dm_target *ti, struct bio *bio) bool discarded_block; struct dm_bio_prison_cell *cell; struct policy_result lookup_result; - struct per_bio_data *pb; + struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size); - if (from_oblock(block) > from_oblock(cache->origin_blocks)) { + 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_clear_discard(cache, bio, block); + remap_to_origin(cache, bio); return DM_MAPIO_REMAPPED; } - pb = init_per_bio_data(bio, pb_data_size); - if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) { defer_bio(cache, bio); return DM_MAPIO_SUBMITTED; @@ -2207,17 +2467,38 @@ static int cache_map(struct dm_target *ti, struct bio *bio) return DM_MAPIO_SUBMITTED; } + r = DM_MAPIO_REMAPPED; switch (lookup_result.op) { case POLICY_HIT: - inc_hit_counter(cache, bio); - pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); + if (passthrough_mode(&cache->features)) { + if (bio_data_dir(bio) == WRITE) { + /* + * We need to invalidate this block, so + * defer for the worker thread. + */ + cell_defer(cache, cell, true); + r = DM_MAPIO_SUBMITTED; + + } else { + pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); + inc_miss_counter(cache, bio); + remap_to_origin_clear_discard(cache, bio, block); + + cell_defer(cache, cell, false); + } - 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); + } else { + inc_hit_counter(cache, bio); + pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); - cell_defer(cache, cell, false); + if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) && + !is_dirty(cache, lookup_result.cblock)) + remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); + else + remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); + + cell_defer(cache, cell, false); + } break; case POLICY_MISS: @@ -2242,10 +2523,10 @@ static int cache_map(struct dm_target *ti, struct bio *bio) DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__, (unsigned) lookup_result.op); bio_io_error(bio); - return DM_MAPIO_SUBMITTED; + r = DM_MAPIO_SUBMITTED; } - return DM_MAPIO_REMAPPED; + return r; } static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) @@ -2286,16 +2567,16 @@ static int write_discard_bitset(struct cache *cache) { unsigned i, r; - r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size, - cache->discard_nr_blocks); + r = dm_cache_discard_bitset_resize(cache->cmd, cache->sectors_per_block, + cache->origin_blocks); if (r) { DMERR("could not resize on-disk discard bitset"); 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))); + for (i = 0; i < from_oblock(cache->discard_nr_blocks); i++) { + r = dm_cache_set_discard(cache->cmd, to_oblock(i), + is_discarded(cache, to_oblock(i))); if (r) return r; } @@ -2303,30 +2584,6 @@ static int write_discard_bitset(struct cache *cache) return 0; } -static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, - uint32_t hint) -{ - struct cache *cache = context; - return dm_cache_save_hint(cache->cmd, cblock, hint); -} - -static int write_hints(struct cache *cache) -{ - int r; - - r = dm_cache_begin_hints(cache->cmd, cache->policy); - if (r) { - DMERR("dm_cache_begin_hints failed"); - return r; - } - - r = policy_walk_mappings(cache->policy, save_hint, cache); - if (r) - DMERR("policy_walk_mappings failed"); - - return r; -} - /* * returns true on success */ @@ -2344,7 +2601,7 @@ static bool sync_metadata(struct cache *cache) save_stats(cache); - r3 = write_hints(cache); + r3 = dm_cache_write_hints(cache->cmd, cache->policy); if (r3) DMERR("could not write hints"); @@ -2392,16 +2649,56 @@ static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock, } static int load_discard(void *context, sector_t discard_block_size, - dm_dblock_t dblock, bool discard) + dm_oblock_t oblock, bool discard) { struct cache *cache = context; - /* FIXME: handle mis-matched block size */ - if (discard) - set_discard(cache, dblock); + set_discard(cache, oblock); else - clear_discard(cache, dblock); + clear_discard(cache, oblock); + + 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("unable to shrink cache; cache block %llu is dirty", + (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("could not resize cache metadata"); + return r; + } + + cache->cache_size = new_size; return 0; } @@ -2410,22 +2707,25 @@ static int cache_preresume(struct dm_target *ti) { int r = 0; struct cache *cache = ti->private; - sector_t actual_cache_size = get_dev_size(cache->cache_dev); - (void) sector_div(actual_cache_size, cache->sectors_per_block); + dm_cblock_t csize = get_cache_dev_size(cache); /* * Check to see if the cache has resized. */ - if (from_cblock(cache->cache_size) != actual_cache_size || !cache->sized) { - cache->cache_size = to_cblock(actual_cache_size); - - r = dm_cache_resize(cache->cmd, cache->cache_size); - if (r) { - DMERR("could not resize cache metadata"); + 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) { @@ -2463,12 +2763,13 @@ static void cache_resume(struct dm_target *ti) /* * Status format: * - * <#used metadata blocks>/<#total metadata blocks> + * <metadata block size> <#used metadata blocks>/<#total metadata blocks> + * <cache block size> <#used cache blocks>/<#total cache blocks> * <#read hits> <#read misses> <#write hits> <#write misses> - * <#demotions> <#promotions> <#blocks in cache> <#dirty> + * <#demotions> <#promotions> <#dirty> * <#features> <features>* * <#core args> <core args> - * <#policy args> <policy args>* + * <policy name> <#policy args> <policy args>* */ static void cache_status(struct dm_target *ti, status_type_t type, unsigned status_flags, char *result, unsigned maxlen) @@ -2506,24 +2807,38 @@ static void cache_status(struct dm_target *ti, status_type_t type, residency = policy_residency(cache->policy); - DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ", + DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %lu ", + (unsigned)(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT), (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), (unsigned long long)nr_blocks_metadata, + cache->sectors_per_block, + (unsigned long long) from_cblock(residency), + (unsigned long long) from_cblock(cache->cache_size), (unsigned) atomic_read(&cache->stats.read_hit), (unsigned) atomic_read(&cache->stats.read_miss), (unsigned) atomic_read(&cache->stats.write_hit), (unsigned) atomic_read(&cache->stats.write_miss), (unsigned) atomic_read(&cache->stats.demotion), (unsigned) atomic_read(&cache->stats.promotion), - (unsigned long long) from_cblock(residency), - cache->nr_dirty); + (unsigned long) atomic_read(&cache->nr_dirty)); - if (cache->features.write_through) + if (writethrough_mode(&cache->features)) DMEMIT("1 writethrough "); - else - DMEMIT("0 "); + + else if (passthrough_mode(&cache->features)) + DMEMIT("1 passthrough "); + + else if (writeback_mode(&cache->features)) + DMEMIT("1 writeback "); + + else { + DMERR("internal error: unknown io mode: %d", (int) cache->features.io_mode); + goto err; + } DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold); + + DMEMIT("%s ", dm_cache_policy_get_name(cache->policy)); if (sz < maxlen) { r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz); if (r) @@ -2553,7 +2868,128 @@ err: } /* - * Supports <key> <value>. + * A cache block range can take two forms: + * + * i) A single cblock, eg. '3456' + * ii) A begin and end cblock with dots between, eg. 123-234 + */ +static int parse_cblock_range(struct cache *cache, const char *str, + struct cblock_range *result) +{ + char dummy; + uint64_t b, e; + int r; + + /* + * Try and parse form (ii) first. + */ + r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy); + if (r < 0) + return r; + + if (r == 2) { + result->begin = to_cblock(b); + result->end = to_cblock(e); + return 0; + } + + /* + * That didn't work, try form (i). + */ + r = sscanf(str, "%llu%c", &b, &dummy); + if (r < 0) + return r; + + if (r == 1) { + result->begin = to_cblock(b); + result->end = to_cblock(from_cblock(result->begin) + 1u); + return 0; + } + + DMERR("invalid cblock range '%s'", str); + return -EINVAL; +} + +static int validate_cblock_range(struct cache *cache, struct cblock_range *range) +{ + uint64_t b = from_cblock(range->begin); + uint64_t e = from_cblock(range->end); + uint64_t n = from_cblock(cache->cache_size); + + if (b >= n) { + DMERR("begin cblock out of range: %llu >= %llu", b, n); + return -EINVAL; + } + + if (e > n) { + DMERR("end cblock out of range: %llu > %llu", e, n); + return -EINVAL; + } + + if (b >= e) { + DMERR("invalid cblock range: %llu >= %llu", b, e); + return -EINVAL; + } + + return 0; +} + +static int request_invalidation(struct cache *cache, struct cblock_range *range) +{ + struct invalidation_request req; + + INIT_LIST_HEAD(&req.list); + req.cblocks = range; + atomic_set(&req.complete, 0); + req.err = 0; + init_waitqueue_head(&req.result_wait); + + spin_lock(&cache->invalidation_lock); + list_add(&req.list, &cache->invalidation_requests); + spin_unlock(&cache->invalidation_lock); + wake_worker(cache); + + wait_event(req.result_wait, atomic_read(&req.complete)); + return req.err; +} + +static int process_invalidate_cblocks_message(struct cache *cache, unsigned count, + const char **cblock_ranges) +{ + int r = 0; + unsigned i; + struct cblock_range range; + + if (!passthrough_mode(&cache->features)) { + DMERR("cache has to be in passthrough mode for invalidation"); + return -EPERM; + } + + for (i = 0; i < count; i++) { + r = parse_cblock_range(cache, cblock_ranges[i], &range); + if (r) + break; + + r = validate_cblock_range(cache, &range); + if (r) + break; + + /* + * Pass begin and end origin blocks to the worker and wake it. + */ + r = request_invalidation(cache, &range); + if (r) + break; + } + + return r; +} + +/* + * Supports + * "<key> <value>" + * and + * "invalidate_cblocks [(<begin>)|(<begin>-<end>)]* * * The key migration_threshold is supported by the cache target core. */ @@ -2561,6 +2997,12 @@ static int cache_message(struct dm_target *ti, unsigned argc, char **argv) { struct cache *cache = ti->private; + if (!argc) + return -EINVAL; + + if (!strcasecmp(argv[0], "invalidate_cblocks")) + return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1); + if (argc != 2) return -EINVAL; @@ -2605,8 +3047,8 @@ static void set_discard_limits(struct cache *cache, struct queue_limits *limits) /* * FIXME: these limits may be incompatible with the cache device */ - limits->max_discard_sectors = cache->discard_block_size * 1024; - limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT; + limits->max_discard_sectors = cache->sectors_per_block; + limits->discard_granularity = cache->sectors_per_block << SECTOR_SHIFT; } static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) @@ -2630,7 +3072,7 @@ static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) static struct target_type cache_target = { .name = "cache", - .version = {1, 1, 1}, + .version = {1, 4, 0}, .module = THIS_MODULE, .ctr = cache_ctr, .dtr = cache_dtr, |