diff options
Diffstat (limited to 'drivers/md/dm-cache-target.c')
| -rw-r--r-- | drivers/md/dm-cache-target.c | 832 |
1 files changed, 659 insertions, 173 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 41b2594a80c6..1b4e1756b169 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -25,44 +25,93 @@ DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle, /*----------------------------------------------------------------*/ -/* - * 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 - */ +#define IOT_RESOLUTION 4 -/*----------------------------------------------------------------*/ +struct io_tracker { + spinlock_t lock; -static size_t bitset_size_in_bytes(unsigned nr_entries) + /* + * 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) { - return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG); + spin_lock_init(&iot->lock); + iot->in_flight = 0ul; + iot->idle_time = 0ul; + iot->last_update_time = jiffies; } -static unsigned long *alloc_bitset(unsigned nr_entries) +static bool __iot_idle_for(struct io_tracker *iot, unsigned long jifs) { - size_t s = bitset_size_in_bytes(nr_entries); - return vzalloc(s); + if (iot->in_flight) + return false; + + return time_after(jiffies, iot->idle_time + jifs); } -static void clear_bitset(void *bitset, unsigned nr_entries) +static bool iot_idle_for(struct io_tracker *iot, unsigned long jifs) { - size_t s = bitset_size_in_bytes(nr_entries); - memset(bitset, 0, s); + 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 free_bitset(unsigned long *bits) +static void iot_io_begin(struct io_tracker *iot, sector_t len) { - vfree(bits); + 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) +{ + 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); } /*----------------------------------------------------------------*/ /* + * 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 + */ + +/*----------------------------------------------------------------*/ + +/* * 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. @@ -101,12 +150,10 @@ static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio) #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT) #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) -/* - * FIXME: the cache is read/write for the time being. - */ enum cache_metadata_mode { CM_WRITE, /* metadata may be changed */ CM_READ_ONLY, /* metadata may not be changed */ + CM_FAIL }; enum cache_io_mode { @@ -208,6 +255,7 @@ struct cache { int sectors_per_block_shift; spinlock_t lock; + struct list_head deferred_cells; struct bio_list deferred_bios; struct bio_list deferred_flush_bios; struct bio_list deferred_writethrough_bios; @@ -282,6 +330,8 @@ struct cache { */ spinlock_t invalidation_lock; struct list_head invalidation_requests; + + struct io_tracker origin_tracker; }; struct per_bio_data { @@ -289,6 +339,7 @@ struct per_bio_data { unsigned req_nr:2; struct dm_deferred_entry *all_io_entry; struct dm_hook_info hook_info; + sector_t len; /* * writethrough fields. These MUST remain at the end of this @@ -332,6 +383,8 @@ struct prealloc { struct dm_bio_prison_cell *cell2; }; +static enum cache_metadata_mode get_cache_mode(struct cache *cache); + static void wake_worker(struct cache *cache) { queue_work(cache->wq, &cache->worker); @@ -365,10 +418,13 @@ static struct dm_cache_migration *alloc_migration(struct cache *cache) static void free_migration(struct dm_cache_migration *mg) { - if (atomic_dec_and_test(&mg->cache->nr_allocated_migrations)) - wake_up(&mg->cache->migration_wait); + struct cache *cache = mg->cache; + + if (atomic_dec_and_test(&cache->nr_allocated_migrations)) + wake_up(&cache->migration_wait); - mempool_free(mg, mg->cache->migration_pool); + mempool_free(mg, cache->migration_pool); + wake_worker(cache); } static int prealloc_data_structs(struct cache *cache, struct prealloc *p) @@ -643,6 +699,9 @@ 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); @@ -695,6 +754,7 @@ static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size) pb->tick = false; pb->req_nr = dm_bio_get_target_bio_nr(bio); pb->all_io_entry = NULL; + pb->len = 0; return pb; } @@ -792,12 +852,43 @@ static void inc_ds(struct cache *cache, struct bio *bio, pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds); } +static bool accountable_bio(struct cache *cache, struct bio *bio) +{ + return ((bio->bi_bdev == cache->origin_dev->bdev) && + !(bio->bi_rw & REQ_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->origin_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->origin_tracker, pb->len); +} + +static void accounted_request(struct cache *cache, struct bio *bio) +{ + accounted_begin(cache, bio); + generic_make_request(bio); +} + static void issue(struct cache *cache, struct bio *bio) { unsigned long flags; if (!bio_triggers_commit(cache, bio)) { - generic_make_request(bio); + accounted_request(cache, bio); return; } @@ -870,6 +961,94 @@ static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, } /*---------------------------------------------------------------- + * 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 = dm_cache_metadata_needs_check(cache->cmd); + enum cache_metadata_mode old_mode = get_cache_mode(cache); + + 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); +} + +/*---------------------------------------------------------------- * Migration processing * * Migration covers moving data from the origin device to the cache, or @@ -885,26 +1064,63 @@ static void dec_io_migrations(struct cache *cache) atomic_dec(&cache->nr_io_migrations); } -static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, - bool holder) +static void __cell_release(struct cache *cache, struct dm_bio_prison_cell *cell, + bool holder, struct bio_list *bios) { (holder ? dm_cell_release : dm_cell_release_no_holder) - (cache->prison, cell, &cache->deferred_bios); + (cache->prison, cell, bios); free_prison_cell(cache, cell); } -static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, - bool holder) +static bool discard_or_flush(struct bio *bio) +{ + return bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD); +} + +static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell) +{ + if (discard_or_flush(cell->holder)) + /* + * We have to handle these bios + * individually. + */ + __cell_release(cache, cell, true, &cache->deferred_bios); + + else + list_add_tail(&cell->user_list, &cache->deferred_cells); +} + +static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, bool holder) { unsigned long flags; + if (!holder && dm_cell_promote_or_release(cache->prison, cell)) { + /* + * There was no prisoner to promote to holder, the + * cell has been released. + */ + free_prison_cell(cache, cell); + return; + } + spin_lock_irqsave(&cache->lock, flags); - __cell_defer(cache, cell, holder); + __cell_defer(cache, cell); spin_unlock_irqrestore(&cache->lock, flags); wake_worker(cache); } +static void cell_error_with_code(struct cache *cache, struct dm_bio_prison_cell *cell, int err) +{ + dm_cell_error(cache->prison, cell, err); + dm_bio_prison_free_cell(cache->prison, cell); +} + +static void cell_requeue(struct cache *cache, struct dm_bio_prison_cell *cell) +{ + cell_error_with_code(cache, cell, DM_ENDIO_REQUEUE); +} + static void free_io_migration(struct dm_cache_migration *mg) { dec_io_migrations(mg->cache); @@ -914,21 +1130,22 @@ static void free_io_migration(struct dm_cache_migration *mg) static void migration_failure(struct dm_cache_migration *mg) { struct cache *cache = mg->cache; + const char *dev_name = cache_device_name(cache); if (mg->writeback) { - DMWARN_LIMIT("writeback failed; couldn't copy block"); + DMERR_LIMIT("%s: writeback failed; couldn't copy block", dev_name); set_dirty(cache, mg->old_oblock, mg->cblock); cell_defer(cache, mg->old_ocell, false); } else if (mg->demote) { - DMWARN_LIMIT("demotion failed; couldn't copy block"); + DMERR_LIMIT("%s: demotion failed; couldn't copy block", dev_name); policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); cell_defer(cache, mg->old_ocell, mg->promote ? false : true); if (mg->promote) cell_defer(cache, mg->new_ocell, true); } else { - DMWARN_LIMIT("promotion failed; couldn't copy block"); + DMERR_LIMIT("%s: promotion failed; couldn't copy block", dev_name); policy_remove_mapping(cache->policy, mg->new_oblock); cell_defer(cache, mg->new_ocell, true); } @@ -938,6 +1155,7 @@ static void migration_failure(struct dm_cache_migration *mg) static void migration_success_pre_commit(struct dm_cache_migration *mg) { + int r; unsigned long flags; struct cache *cache = mg->cache; @@ -948,8 +1166,11 @@ static void migration_success_pre_commit(struct dm_cache_migration *mg) return; } else if (mg->demote) { - if (dm_cache_remove_mapping(cache->cmd, mg->cblock)) { - DMWARN_LIMIT("demotion failed; couldn't update on disk metadata"); + r = dm_cache_remove_mapping(cache->cmd, mg->cblock); + if (r) { + DMERR_LIMIT("%s: demotion failed; couldn't update on disk metadata", + cache_device_name(cache)); + metadata_operation_failed(cache, "dm_cache_remove_mapping", r); policy_force_mapping(cache->policy, mg->new_oblock, mg->old_oblock); if (mg->promote) @@ -958,8 +1179,11 @@ static void migration_success_pre_commit(struct dm_cache_migration *mg) return; } } else { - if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) { - DMWARN_LIMIT("promotion failed; couldn't update on disk metadata"); + r = dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock); + if (r) { + DMERR_LIMIT("%s: promotion failed; couldn't update on disk metadata", + cache_device_name(cache)); + metadata_operation_failed(cache, "dm_cache_insert_mapping", r); policy_remove_mapping(cache->policy, mg->new_oblock); free_io_migration(mg); return; @@ -978,7 +1202,8 @@ static void migration_success_post_commit(struct dm_cache_migration *mg) struct cache *cache = mg->cache; if (mg->writeback) { - DMWARN("writeback unexpectedly triggered commit"); + DMWARN_LIMIT("%s: writeback unexpectedly triggered commit", + cache_device_name(cache)); return; } else if (mg->demote) { @@ -1054,7 +1279,7 @@ static void issue_copy(struct dm_cache_migration *mg) } if (r < 0) { - DMERR_LIMIT("issuing migration failed"); + DMERR_LIMIT("%s: issuing migration failed", cache_device_name(cache)); migration_failure(mg); } } @@ -1093,7 +1318,7 @@ static void issue_overwrite(struct dm_cache_migration *mg, struct bio *bio) * No need to inc_ds() here, since the cell will be held for the * duration of the io. */ - generic_make_request(bio); + accounted_request(mg->cache, bio); } static bool bio_writes_complete_block(struct cache *cache, struct bio *bio) @@ -1439,32 +1664,154 @@ static void inc_miss_counter(struct cache *cache, struct bio *bio) &cache->stats.read_miss : &cache->stats.write_miss); } -static void process_bio(struct cache *cache, struct prealloc *structs, - struct bio *bio) +/*----------------------------------------------------------------*/ + +struct inc_detail { + struct cache *cache; + struct bio_list bios_for_issue; + struct bio_list unhandled_bios; + bool any_writes; +}; + +static void inc_fn(void *context, struct dm_bio_prison_cell *cell) +{ + struct bio *bio; + struct inc_detail *detail = context; + struct cache *cache = detail->cache; + + inc_ds(cache, cell->holder, cell); + if (bio_data_dir(cell->holder) == WRITE) + detail->any_writes = true; + + while ((bio = bio_list_pop(&cell->bios))) { + if (discard_or_flush(bio)) { + bio_list_add(&detail->unhandled_bios, bio); + continue; + } + + if (bio_data_dir(bio) == WRITE) + detail->any_writes = true; + + bio_list_add(&detail->bios_for_issue, bio); + inc_ds(cache, bio, cell); + } +} + +// FIXME: refactor these two +static void remap_cell_to_origin_clear_discard(struct cache *cache, + struct dm_bio_prison_cell *cell, + dm_oblock_t oblock, bool issue_holder) +{ + struct bio *bio; + unsigned long flags; + struct inc_detail detail; + + detail.cache = cache; + bio_list_init(&detail.bios_for_issue); + bio_list_init(&detail.unhandled_bios); + detail.any_writes = false; + + spin_lock_irqsave(&cache->lock, flags); + dm_cell_visit_release(cache->prison, inc_fn, &detail, cell); + bio_list_merge(&cache->deferred_bios, &detail.unhandled_bios); + spin_unlock_irqrestore(&cache->lock, flags); + + remap_to_origin(cache, cell->holder); + if (issue_holder) + issue(cache, cell->holder); + else + accounted_begin(cache, cell->holder); + + if (detail.any_writes) + clear_discard(cache, oblock_to_dblock(cache, oblock)); + + while ((bio = bio_list_pop(&detail.bios_for_issue))) { + remap_to_origin(cache, bio); + issue(cache, bio); + } +} + +static void remap_cell_to_cache_dirty(struct cache *cache, struct dm_bio_prison_cell *cell, + dm_oblock_t oblock, dm_cblock_t cblock, bool issue_holder) +{ + struct bio *bio; + unsigned long flags; + struct inc_detail detail; + + detail.cache = cache; + bio_list_init(&detail.bios_for_issue); + bio_list_init(&detail.unhandled_bios); + detail.any_writes = false; + + spin_lock_irqsave(&cache->lock, flags); + dm_cell_visit_release(cache->prison, inc_fn, &detail, cell); + bio_list_merge(&cache->deferred_bios, &detail.unhandled_bios); + spin_unlock_irqrestore(&cache->lock, flags); + + remap_to_cache(cache, cell->holder, cblock); + if (issue_holder) + issue(cache, cell->holder); + else + accounted_begin(cache, cell->holder); + + if (detail.any_writes) { + set_dirty(cache, oblock, cblock); + clear_discard(cache, oblock_to_dblock(cache, oblock)); + } + + while ((bio = bio_list_pop(&detail.bios_for_issue))) { + remap_to_cache(cache, bio, cblock); + issue(cache, bio); + } +} + +/*----------------------------------------------------------------*/ + +struct old_oblock_lock { + struct policy_locker locker; + struct cache *cache; + struct prealloc *structs; + struct dm_bio_prison_cell *cell; +}; + +static int null_locker(struct policy_locker *locker, dm_oblock_t b) +{ + /* This should never be called */ + BUG(); + return 0; +} + +static int cell_locker(struct policy_locker *locker, dm_oblock_t b) +{ + struct old_oblock_lock *l = container_of(locker, struct old_oblock_lock, locker); + struct dm_bio_prison_cell *cell_prealloc = prealloc_get_cell(l->structs); + + return bio_detain(l->cache, b, NULL, cell_prealloc, + (cell_free_fn) prealloc_put_cell, + l->structs, &l->cell); +} + +static void process_cell(struct cache *cache, struct prealloc *structs, + struct dm_bio_prison_cell *new_ocell) { int r; bool release_cell = true; + struct bio *bio = new_ocell->holder; dm_oblock_t block = get_bio_block(cache, bio); - struct dm_bio_prison_cell *cell_prealloc, *old_ocell, *new_ocell; struct policy_result lookup_result; bool passthrough = passthrough_mode(&cache->features); - bool discarded_block, can_migrate; - - /* - * Check to see if that block is currently migrating. - */ - cell_prealloc = prealloc_get_cell(structs); - r = bio_detain(cache, block, bio, cell_prealloc, - (cell_free_fn) prealloc_put_cell, - structs, &new_ocell); - if (r > 0) - return; + bool fast_promotion, can_migrate; + struct old_oblock_lock ool; - discarded_block = is_discarded_oblock(cache, block); - can_migrate = !passthrough && (discarded_block || spare_migration_bandwidth(cache)); + fast_promotion = is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio); + can_migrate = !passthrough && (fast_promotion || spare_migration_bandwidth(cache)); - r = policy_map(cache->policy, block, true, can_migrate, discarded_block, - bio, &lookup_result); + ool.locker.fn = cell_locker; + ool.cache = cache; + ool.structs = structs; + ool.cell = NULL; + r = policy_map(cache->policy, block, true, can_migrate, fast_promotion, + bio, &ool.locker, &lookup_result); if (r == -EWOULDBLOCK) /* migration has been denied */ @@ -1500,9 +1847,9 @@ static void process_bio(struct cache *cache, struct prealloc *structs, remap_to_origin_then_cache(cache, bio, block, lookup_result.cblock); inc_and_issue(cache, bio, new_ocell); - } else { - remap_to_cache_dirty(cache, bio, block, lookup_result.cblock); - inc_and_issue(cache, bio, new_ocell); + } else { + remap_cell_to_cache_dirty(cache, new_ocell, block, lookup_result.cblock, true); + release_cell = false; } } @@ -1510,8 +1857,8 @@ static void process_bio(struct cache *cache, struct prealloc *structs, case POLICY_MISS: inc_miss_counter(cache, bio); - remap_to_origin_clear_discard(cache, bio, block); - inc_and_issue(cache, bio, new_ocell); + remap_cell_to_origin_clear_discard(cache, new_ocell, block, true); + release_cell = false; break; case POLICY_NEW: @@ -1521,32 +1868,17 @@ static void process_bio(struct cache *cache, struct prealloc *structs, break; case POLICY_REPLACE: - cell_prealloc = prealloc_get_cell(structs); - r = bio_detain(cache, lookup_result.old_oblock, bio, cell_prealloc, - (cell_free_fn) prealloc_put_cell, - structs, &old_ocell); - if (r > 0) { - /* - * We have to be careful to avoid lock inversion of - * the cells. So we back off, and wait for the - * old_ocell to become free. - */ - policy_force_mapping(cache->policy, block, - lookup_result.old_oblock); - atomic_inc(&cache->stats.cache_cell_clash); - break; - } atomic_inc(&cache->stats.demotion); atomic_inc(&cache->stats.promotion); - demote_then_promote(cache, structs, lookup_result.old_oblock, block, lookup_result.cblock, - old_ocell, new_ocell); + ool.cell, new_ocell); release_cell = false; break; default: - DMERR_LIMIT("%s: erroring bio, unknown policy op: %u", __func__, + DMERR_LIMIT("%s: %s: erroring bio, unknown policy op: %u", + cache_device_name(cache), __func__, (unsigned) lookup_result.op); bio_io_error(bio); } @@ -1555,10 +1887,48 @@ static void process_bio(struct cache *cache, struct prealloc *structs, cell_defer(cache, new_ocell, false); } +static void process_bio(struct cache *cache, struct prealloc *structs, + struct bio *bio) +{ + int r; + dm_oblock_t block = get_bio_block(cache, bio); + struct dm_bio_prison_cell *cell_prealloc, *new_ocell; + + /* + * Check to see if that block is currently migrating. + */ + cell_prealloc = prealloc_get_cell(structs); + r = bio_detain(cache, block, bio, cell_prealloc, + (cell_free_fn) prealloc_put_cell, + structs, &new_ocell); + if (r > 0) + return; + + process_cell(cache, structs, new_ocell); +} + static int need_commit_due_to_time(struct cache *cache) { - return !time_in_range(jiffies, cache->last_commit_jiffies, - cache->last_commit_jiffies + COMMIT_PERIOD); + return jiffies < cache->last_commit_jiffies || + jiffies > cache->last_commit_jiffies + COMMIT_PERIOD; +} + +/* + * 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; } static int commit_if_needed(struct cache *cache) @@ -1567,9 +1937,8 @@ static int commit_if_needed(struct cache *cache) if ((cache->commit_requested || need_commit_due_to_time(cache)) && dm_cache_changed_this_transaction(cache->cmd)) { - atomic_inc(&cache->stats.commit_count); + r = commit(cache, false); cache->commit_requested = false; - r = dm_cache_commit(cache->cmd, false); cache->last_commit_jiffies = jiffies; } @@ -1617,6 +1986,40 @@ static void process_deferred_bios(struct cache *cache) prealloc_free_structs(cache, &structs); } +static void process_deferred_cells(struct cache *cache) +{ + unsigned long flags; + struct dm_bio_prison_cell *cell, *tmp; + struct list_head cells; + struct prealloc structs; + + memset(&structs, 0, sizeof(structs)); + + INIT_LIST_HEAD(&cells); + + spin_lock_irqsave(&cache->lock, flags); + list_splice_init(&cache->deferred_cells, &cells); + spin_unlock_irqrestore(&cache->lock, flags); + + list_for_each_entry_safe(cell, tmp, &cells, user_list) { + /* + * If we've got no free migration structs, and processing + * this bio might require one, we pause until there are some + * prepared mappings to process. + */ + if (prealloc_data_structs(cache, &structs)) { + spin_lock_irqsave(&cache->lock, flags); + list_splice(&cells, &cache->deferred_cells); + spin_unlock_irqrestore(&cache->lock, flags); + break; + } + + process_cell(cache, &structs, cell); + } + + prealloc_free_structs(cache, &structs); +} + static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) { unsigned long flags; @@ -1634,7 +2037,7 @@ static void process_deferred_flush_bios(struct cache *cache, bool submit_bios) * These bios have already been through inc_ds() */ while ((bio = bio_list_pop(&bios))) - submit_bios ? generic_make_request(bio) : bio_io_error(bio); + submit_bios ? accounted_request(cache, bio) : bio_io_error(bio); } static void process_deferred_writethrough_bios(struct cache *cache) @@ -1654,7 +2057,7 @@ static void process_deferred_writethrough_bios(struct cache *cache) * These bios have already been through inc_ds() */ while ((bio = bio_list_pop(&bios))) - generic_make_request(bio); + accounted_request(cache, bio); } static void writeback_some_dirty_blocks(struct cache *cache) @@ -1664,6 +2067,7 @@ static void writeback_some_dirty_blocks(struct cache *cache) dm_cblock_t cblock; struct prealloc structs; struct dm_bio_prison_cell *old_ocell; + bool busy = !iot_idle_for(&cache->origin_tracker, HZ); memset(&structs, 0, sizeof(structs)); @@ -1671,7 +2075,7 @@ static void writeback_some_dirty_blocks(struct cache *cache) if (prealloc_data_structs(cache, &structs)) break; - r = policy_writeback_work(cache->policy, &oblock, &cblock); + r = policy_writeback_work(cache->policy, &oblock, &cblock, busy); if (r) break; @@ -1702,15 +2106,17 @@ static void process_invalidation_request(struct cache *cache, struct invalidatio r = policy_remove_cblock(cache->policy, to_cblock(begin)); if (!r) { r = dm_cache_remove_mapping(cache->cmd, to_cblock(begin)); - if (r) + if (r) { + metadata_operation_failed(cache, "dm_cache_remove_mapping", r); break; + } } else if (r == -ENODATA) { /* harmless, already unmapped */ r = 0; } else { - DMERR("policy_remove_cblock failed"); + DMERR("%s: policy_remove_cblock failed", cache_device_name(cache)); break; } @@ -1783,7 +2189,22 @@ static void stop_worker(struct cache *cache) flush_workqueue(cache->wq); } -static void requeue_deferred_io(struct cache *cache) +static void requeue_deferred_cells(struct cache *cache) +{ + unsigned long flags; + struct list_head cells; + struct dm_bio_prison_cell *cell, *tmp; + + INIT_LIST_HEAD(&cells); + spin_lock_irqsave(&cache->lock, flags); + list_splice_init(&cache->deferred_cells, &cells); + spin_unlock_irqrestore(&cache->lock, flags); + + list_for_each_entry_safe(cell, tmp, &cells, user_list) + cell_requeue(cache, cell); +} + +static void requeue_deferred_bios(struct cache *cache) { struct bio *bio; struct bio_list bios; @@ -1804,6 +2225,7 @@ static int more_work(struct cache *cache) !list_empty(&cache->need_commit_migrations); else return !bio_list_empty(&cache->deferred_bios) || + !list_empty(&cache->deferred_cells) || !bio_list_empty(&cache->deferred_flush_bios) || !bio_list_empty(&cache->deferred_writethrough_bios) || !list_empty(&cache->quiesced_migrations) || @@ -1821,6 +2243,7 @@ static void do_worker(struct work_struct *ws) writeback_some_dirty_blocks(cache); process_deferred_writethrough_bios(cache); process_deferred_bios(cache); + process_deferred_cells(cache); process_invalidation_requests(cache); } @@ -1830,11 +2253,6 @@ static void do_worker(struct work_struct *ws) if (commit_if_needed(cache)) { process_deferred_flush_bios(cache, false); process_migrations(cache, &cache->need_commit_migrations, migration_failure); - - /* - * FIXME: rollback metadata or just go into a - * failure mode and error everything - */ } else { process_deferred_flush_bios(cache, true); process_migrations(cache, &cache->need_commit_migrations, @@ -1853,7 +2271,7 @@ static void do_worker(struct work_struct *ws) static void do_waker(struct work_struct *ws) { struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker); - policy_tick(cache->policy); + policy_tick(cache->policy, true); wake_worker(cache); queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD); } @@ -2407,6 +2825,12 @@ static int cache_create(struct cache_args *ca, struct cache **result) 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; @@ -2425,6 +2849,7 @@ static int cache_create(struct cache_args *ca, struct cache **result) } spin_lock_init(&cache->lock); + INIT_LIST_HEAD(&cache->deferred_cells); bio_list_init(&cache->deferred_bios); bio_list_init(&cache->deferred_flush_bios); bio_list_init(&cache->deferred_writethrough_bios); @@ -2514,6 +2939,8 @@ static int cache_create(struct cache_args *ca, struct cache **result) spin_lock_init(&cache->invalidation_lock); INIT_LIST_HEAD(&cache->invalidation_requests); + iot_init(&cache->origin_tracker); + *result = cache; return 0; @@ -2580,15 +3007,23 @@ out: return r; } -static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_prison_cell **cell) +/*----------------------------------------------------------------*/ + +static int cache_map(struct dm_target *ti, struct bio *bio) { + struct cache *cache = ti->private; + int r; + struct dm_bio_prison_cell *cell = NULL; dm_oblock_t block = get_bio_block(cache, bio); size_t pb_data_size = get_per_bio_data_size(cache); bool can_migrate = false; - bool discarded_block; + bool fast_promotion; struct policy_result lookup_result; struct per_bio_data *pb = init_per_bio_data(bio, pb_data_size); + struct old_oblock_lock ool; + + ool.locker.fn = null_locker; if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) { /* @@ -2597,10 +3032,11 @@ static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_priso * Just remap to the origin and carry on. */ remap_to_origin(cache, bio); + accounted_begin(cache, bio); return DM_MAPIO_REMAPPED; } - if (bio->bi_rw & (REQ_FLUSH | REQ_FUA | REQ_DISCARD)) { + if (discard_or_flush(bio)) { defer_bio(cache, bio); return DM_MAPIO_SUBMITTED; } @@ -2608,15 +3044,15 @@ static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_priso /* * Check to see if that block is currently migrating. */ - *cell = alloc_prison_cell(cache); - if (!*cell) { + cell = alloc_prison_cell(cache); + if (!cell) { defer_bio(cache, bio); return DM_MAPIO_SUBMITTED; } - r = bio_detain(cache, block, bio, *cell, + r = bio_detain(cache, block, bio, cell, (cell_free_fn) free_prison_cell, - cache, cell); + cache, &cell); if (r) { if (r < 0) defer_bio(cache, bio); @@ -2624,17 +3060,18 @@ static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_priso return DM_MAPIO_SUBMITTED; } - discarded_block = is_discarded_oblock(cache, block); + fast_promotion = is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio); - r = policy_map(cache->policy, block, false, can_migrate, discarded_block, - bio, &lookup_result); + r = policy_map(cache->policy, block, false, can_migrate, fast_promotion, + bio, &ool.locker, &lookup_result); if (r == -EWOULDBLOCK) { - cell_defer(cache, *cell, true); + cell_defer(cache, cell, true); return DM_MAPIO_SUBMITTED; } else if (r) { - DMERR_LIMIT("Unexpected return from cache replacement policy: %d", r); - cell_defer(cache, *cell, false); + DMERR_LIMIT("%s: Unexpected return from cache replacement policy: %d", + cache_device_name(cache), r); + cell_defer(cache, cell, false); bio_io_error(bio); return DM_MAPIO_SUBMITTED; } @@ -2648,21 +3085,30 @@ static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_priso * We need to invalidate this block, so * defer for the worker thread. */ - cell_defer(cache, *cell, true); + cell_defer(cache, cell, true); r = DM_MAPIO_SUBMITTED; } else { inc_miss_counter(cache, bio); remap_to_origin_clear_discard(cache, bio, block); + accounted_begin(cache, bio); + inc_ds(cache, bio, cell); + // FIXME: we want to remap hits or misses straight + // away rather than passing over to the worker. + cell_defer(cache, cell, false); } } else { inc_hit_counter(cache, bio); if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) && - !is_dirty(cache, lookup_result.cblock)) + !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); + accounted_begin(cache, bio); + inc_ds(cache, bio, cell); + cell_defer(cache, cell, false); + + } else + remap_cell_to_cache_dirty(cache, cell, block, lookup_result.cblock, false); } break; @@ -2674,18 +3120,19 @@ static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_priso * longer needed because the block has been demoted. */ bio_endio(bio, 0); - cell_defer(cache, *cell, false); + // FIXME: remap everything as a miss + cell_defer(cache, cell, false); r = DM_MAPIO_SUBMITTED; } else - remap_to_origin_clear_discard(cache, bio, block); - + remap_cell_to_origin_clear_discard(cache, cell, block, false); break; default: - DMERR_LIMIT("%s: erroring bio: unknown policy op: %u", __func__, + DMERR_LIMIT("%s: %s: erroring bio: unknown policy op: %u", + cache_device_name(cache), __func__, (unsigned) lookup_result.op); - cell_defer(cache, *cell, false); + cell_defer(cache, cell, false); bio_io_error(bio); r = DM_MAPIO_SUBMITTED; } @@ -2693,21 +3140,6 @@ static int __cache_map(struct cache *cache, struct bio *bio, struct dm_bio_priso return r; } -static int cache_map(struct dm_target *ti, struct bio *bio) -{ - int r; - struct dm_bio_prison_cell *cell = NULL; - struct cache *cache = ti->private; - - r = __cache_map(cache, bio, &cell); - if (r == DM_MAPIO_REMAPPED && cell) { - inc_ds(cache, bio, cell); - cell_defer(cache, cell, false); - } - - return r; -} - static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) { struct cache *cache = ti->private; @@ -2716,7 +3148,7 @@ static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size); if (pb->tick) { - policy_tick(cache->policy); + policy_tick(cache->policy, false); spin_lock_irqsave(&cache->lock, flags); cache->need_tick_bio = true; @@ -2724,6 +3156,7 @@ static int cache_end_io(struct dm_target *ti, struct bio *bio, int error) } check_for_quiesced_migrations(cache, pb); + accounted_complete(cache, bio); return 0; } @@ -2732,11 +3165,16 @@ static int write_dirty_bitset(struct cache *cache) { unsigned i, r; + if (get_cache_mode(cache) >= CM_READ_ONLY) + return -EINVAL; + for (i = 0; i < from_cblock(cache->cache_size); i++) { r = dm_cache_set_dirty(cache->cmd, to_cblock(i), is_dirty(cache, to_cblock(i))); - if (r) + if (r) { + metadata_operation_failed(cache, "dm_cache_set_dirty", r); return r; + } } return 0; @@ -2746,18 +3184,40 @@ 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("could not resize on-disk discard bitset"); + 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) + 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; @@ -2772,26 +3232,26 @@ static bool sync_metadata(struct cache *cache) r1 = write_dirty_bitset(cache); if (r1) - DMERR("could not write dirty bitset"); + DMERR("%s: could not write dirty bitset", cache_device_name(cache)); r2 = write_discard_bitset(cache); if (r2) - DMERR("could not write discard bitset"); + DMERR("%s: could not write discard bitset", cache_device_name(cache)); save_stats(cache); - r3 = dm_cache_write_hints(cache->cmd, cache->policy); + r3 = write_hints(cache); if (r3) - DMERR("could not write hints"); + 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 = dm_cache_commit(cache->cmd, !r1 && !r2 && !r3); + r4 = commit(cache, !r1 && !r2 && !r3); if (r4) - DMERR("could not write cache metadata. Data loss may occur."); + DMERR("%s: could not write cache metadata", cache_device_name(cache)); return !r1 && !r2 && !r3 && !r4; } @@ -2803,10 +3263,12 @@ static void cache_postsuspend(struct dm_target *ti) start_quiescing(cache); wait_for_migrations(cache); stop_worker(cache); - requeue_deferred_io(cache); + requeue_deferred_bios(cache); + requeue_deferred_cells(cache); stop_quiescing(cache); - (void) sync_metadata(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, @@ -2929,7 +3391,8 @@ static bool can_resize(struct cache *cache, dm_cblock_t new_size) 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", + DMERR("%s: unable to shrink cache; cache block %llu is dirty", + cache_device_name(cache), (unsigned long long) from_cblock(new_size)); return false; } @@ -2944,7 +3407,8 @@ static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size) r = dm_cache_resize(cache->cmd, new_size); if (r) { - DMERR("could not resize cache metadata"); + DMERR("%s: could not resize cache metadata", cache_device_name(cache)); + metadata_operation_failed(cache, "dm_cache_resize", r); return r; } @@ -2982,7 +3446,8 @@ static int cache_preresume(struct dm_target *ti) r = dm_cache_load_mappings(cache->cmd, cache->policy, load_mapping, cache); if (r) { - DMERR("could not load cache mappings"); + DMERR("%s: could not load cache mappings", cache_device_name(cache)); + metadata_operation_failed(cache, "dm_cache_load_mappings", r); return r; } @@ -3002,7 +3467,8 @@ static int cache_preresume(struct dm_target *ti) discard_load_info_init(cache, &li); r = dm_cache_load_discards(cache->cmd, load_discard, &li); if (r) { - DMERR("could not load origin discards"); + 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); @@ -3030,7 +3496,7 @@ static void cache_resume(struct dm_target *ti) * <#demotions> <#promotions> <#dirty> * <#features> <features>* * <#core args> <core args> - * <policy name> <#policy args> <policy args>* + * <policy name> <#policy args> <policy args>* <cache metadata mode> */ static void cache_status(struct dm_target *ti, status_type_t type, unsigned status_flags, char *result, unsigned maxlen) @@ -3046,23 +3512,26 @@ static void cache_status(struct dm_target *ti, status_type_t type, switch (type) { case STATUSTYPE_INFO: - /* Commit to ensure statistics aren't out-of-date */ - if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) { - r = dm_cache_commit(cache->cmd, false); - if (r) - DMERR("could not commit metadata for accurate status"); + if (get_cache_mode(cache) == CM_FAIL) { + DMEMIT("Fail"); + break; } - r = dm_cache_get_free_metadata_block_count(cache->cmd, - &nr_free_blocks_metadata); + /* Commit to ensure statistics aren't out-of-date */ + if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) + (void) commit(cache, false); + + r = dm_cache_get_free_metadata_block_count(cache->cmd, &nr_free_blocks_metadata); if (r) { - DMERR("could not get metadata free block count"); + DMERR("%s: dm_cache_get_free_metadata_block_count returned %d", + cache_device_name(cache), r); goto err; } r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata); if (r) { - DMERR("could not get metadata device size"); + DMERR("%s: dm_cache_get_metadata_dev_size returned %d", + cache_device_name(cache), r); goto err; } @@ -3093,7 +3562,8 @@ static void cache_status(struct dm_target *ti, status_type_t type, DMEMIT("1 writeback "); else { - DMERR("internal error: unknown io mode: %d", (int) cache->features.io_mode); + DMERR("%s: internal error: unknown io mode: %d", + cache_device_name(cache), (int) cache->features.io_mode); goto err; } @@ -3101,11 +3571,17 @@ static void cache_status(struct dm_target *ti, status_type_t type, DMEMIT("%s ", dm_cache_policy_get_name(cache->policy)); if (sz < maxlen) { - r = policy_emit_config_values(cache->policy, result + sz, maxlen - sz); + r = policy_emit_config_values(cache->policy, result, maxlen, &sz); if (r) - DMERR("policy_emit_config_values returned %d", r); + DMERR("%s: policy_emit_config_values returned %d", + cache_device_name(cache), r); } + if (get_cache_mode(cache) == CM_READ_ONLY) + DMEMIT("ro "); + else + DMEMIT("rw "); + break; case STATUSTYPE_TABLE: @@ -3167,7 +3643,7 @@ static int parse_cblock_range(struct cache *cache, const char *str, return 0; } - DMERR("invalid cblock range '%s'", str); + DMERR("%s: invalid cblock range '%s'", cache_device_name(cache), str); return -EINVAL; } @@ -3178,17 +3654,20 @@ static int validate_cblock_range(struct cache *cache, struct cblock_range *range uint64_t n = from_cblock(cache->cache_size); if (b >= n) { - DMERR("begin cblock out of range: %llu >= %llu", b, n); + DMERR("%s: begin cblock out of range: %llu >= %llu", + cache_device_name(cache), b, n); return -EINVAL; } if (e > n) { - DMERR("end cblock out of range: %llu > %llu", e, n); + DMERR("%s: end cblock out of range: %llu > %llu", + cache_device_name(cache), e, n); return -EINVAL; } if (b >= e) { - DMERR("invalid cblock range: %llu >= %llu", b, e); + DMERR("%s: invalid cblock range: %llu >= %llu", + cache_device_name(cache), b, e); return -EINVAL; } @@ -3222,7 +3701,8 @@ static int process_invalidate_cblocks_message(struct cache *cache, unsigned coun struct cblock_range range; if (!passthrough_mode(&cache->features)) { - DMERR("cache has to be in passthrough mode for invalidation"); + DMERR("%s: cache has to be in passthrough mode for invalidation", + cache_device_name(cache)); return -EPERM; } @@ -3261,6 +3741,12 @@ static int cache_message(struct dm_target *ti, unsigned argc, char **argv) if (!argc) return -EINVAL; + if (get_cache_mode(cache) >= CM_READ_ONLY) { + DMERR("%s: unable to service cache target messages in READ_ONLY or FAIL mode", + cache_device_name(cache)); + return -EOPNOTSUPP; + } + if (!strcasecmp(argv[0], "invalidate_cblocks")) return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1); @@ -3334,7 +3820,7 @@ static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) static struct target_type cache_target = { .name = "cache", - .version = {1, 6, 0}, + .version = {1, 7, 0}, .module = THIS_MODULE, .ctr = cache_ctr, .dtr = cache_dtr, |