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Commit bfc835b5 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'dm-3.19-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm 

Pull device mapper fixes from Mike Snitzer:
 "Two stable fixes for dm-cache and one 3.19 DM core fix:

   - fix potential for dm-cache metadata corruption via stale metadata
     buffers being used when switching an inactive cache table to
     active; this could occur due to each table having it's own bufio
     client rather than sharing the client between tables.

   - fix dm-cache target to properly account for discard IO while
     suspending otherwise IO quiescing could complete prematurely.

   - fix DM core's handling of multiple internal suspends by maintaining
     an 'internal_suspend_count' and only resuming the device when this
     count drops to zero"

* tag 'dm-3.19-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: fix handling of multiple internal suspends
  dm cache: fix problematic dual use of a single migration count variable
  dm cache: share cache-metadata object across inactive and active DM tables
parents 8e908e99 96b26c8c

drivers/md/dm-cache-metadata.c

+95 −6
Original line number Diff line number Diff line
@@ -94,6 +94,9 @@ struct cache_disk_superblock { 
} __packed;



struct dm_cache_metadata {

	atomic_t ref_count;

	struct list_head list;



	struct block_device *bdev;

	struct dm_block_manager *bm;

	struct dm_space_map *metadata_sm;
@@ -669,7 +672,7 @@ static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags) 


/*----------------------------------------------------------------*/



struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,

static struct dm_cache_metadata *metadata_open(struct block_device *bdev,

					       sector_t data_block_size,

					       bool may_format_device,

					       size_t policy_hint_size)
@@ -683,6 +686,7 @@ struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 
		return NULL;

	}



	atomic_set(&cmd->ref_count, 1);

	init_rwsem(&cmd->root_lock);

	cmd->bdev = bdev;

	cmd->data_block_size = data_block_size;
@@ -705,11 +709,96 @@ struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, 
	return cmd;

}



/*

 * We keep a little list of ref counted metadata objects to prevent two

 * different target instances creating separate bufio instances.  This is

 * an issue if a table is reloaded before the suspend.

 */

static DEFINE_MUTEX(table_lock);

static LIST_HEAD(table);



static struct dm_cache_metadata *lookup(struct block_device *bdev)

{

	struct dm_cache_metadata *cmd;



	list_for_each_entry(cmd, &table, list)

		if (cmd->bdev == bdev) {

			atomic_inc(&cmd->ref_count);

			return cmd;

		}



	return NULL;

}



static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,

						sector_t data_block_size,

						bool may_format_device,

						size_t policy_hint_size)

{

	struct dm_cache_metadata *cmd, *cmd2;



	mutex_lock(&table_lock);

	cmd = lookup(bdev);

	mutex_unlock(&table_lock);



	if (cmd)

		return cmd;



	cmd = metadata_open(bdev, data_block_size, may_format_device, policy_hint_size);

	if (cmd) {

		mutex_lock(&table_lock);

		cmd2 = lookup(bdev);

		if (cmd2) {

			mutex_unlock(&table_lock);

			__destroy_persistent_data_objects(cmd);

			kfree(cmd);

			return cmd2;

		}

		list_add(&cmd->list, &table);

		mutex_unlock(&table_lock);

	}



	return cmd;

}



static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)

{

	if (cmd->data_block_size != data_block_size) {

		DMERR("data_block_size (%llu) different from that in metadata (%llu)\n",

		      (unsigned long long) data_block_size,

		      (unsigned long long) cmd->data_block_size);

		return false;

	}



	return true;

}



struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,

						 sector_t data_block_size,

						 bool may_format_device,

						 size_t policy_hint_size)

{

	struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size,

						       may_format_device, policy_hint_size);

	if (cmd && !same_params(cmd, data_block_size)) {

		dm_cache_metadata_close(cmd);

		return NULL;

	}



	return cmd;

}



void dm_cache_metadata_close(struct dm_cache_metadata *cmd)

{

	if (atomic_dec_and_test(&cmd->ref_count)) {

		mutex_lock(&table_lock);

		list_del(&cmd->list);

		mutex_unlock(&table_lock);



		__destroy_persistent_data_objects(cmd);

		kfree(cmd);

	}

}



/*

 * Checks that the given cache block is either unmapped or clean.

drivers/md/dm-cache-target.c

+50 −39
Original line number Diff line number Diff line
@@ -221,7 +221,13 @@ struct cache { 
	struct list_head need_commit_migrations;

	sector_t migration_threshold;

	wait_queue_head_t migration_wait;

	atomic_t nr_migrations;

	atomic_t nr_allocated_migrations;



	/*

	 * The number of in flight migrations that are performing

	 * background io. eg, promotion, writeback.

	 */

	atomic_t nr_io_migrations;



	wait_queue_head_t quiescing_wait;

	atomic_t quiescing;
@@ -258,7 +264,6 @@ struct cache { 
	struct dm_deferred_set *all_io_ds;



	mempool_t *migration_pool;

	struct dm_cache_migration *next_migration;



	struct dm_cache_policy *policy;

	unsigned policy_nr_args;
@@ -350,10 +355,31 @@ static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cel 
	dm_bio_prison_free_cell(cache->prison, cell);

}



static struct dm_cache_migration *alloc_migration(struct cache *cache)

{

	struct dm_cache_migration *mg;



	mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);

	if (mg) {

		mg->cache = cache;

		atomic_inc(&mg->cache->nr_allocated_migrations);

	}



	return mg;

}



static void free_migration(struct dm_cache_migration *mg)

{

	if (atomic_dec_and_test(&mg->cache->nr_allocated_migrations))

		wake_up(&mg->cache->migration_wait);



	mempool_free(mg, mg->cache->migration_pool);

}



static int prealloc_data_structs(struct cache *cache, struct prealloc *p)

{

	if (!p->mg) {

		p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);

		p->mg = alloc_migration(cache);

		if (!p->mg)

			return -ENOMEM;

	}
@@ -382,7 +408,7 @@ static void prealloc_free_structs(struct cache *cache, struct prealloc *p) 
		free_prison_cell(cache, p->cell1);



	if (p->mg)

		mempool_free(p->mg, cache->migration_pool);

		free_migration(p->mg);

}



static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p)
@@ -854,24 +880,14 @@ static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio, 
 * Migration covers moving data from the origin device to the cache, or

 * vice versa.

 *--------------------------------------------------------------*/

static void free_migration(struct dm_cache_migration *mg)

{

	mempool_free(mg, mg->cache->migration_pool);

}



static void inc_nr_migrations(struct cache *cache)

static void inc_io_migrations(struct cache *cache)

{

	atomic_inc(&cache->nr_migrations);

	atomic_inc(&cache->nr_io_migrations);

}



static void dec_nr_migrations(struct cache *cache)

static void dec_io_migrations(struct cache *cache)

{

	atomic_dec(&cache->nr_migrations);



	/*

	 * Wake the worker in case we're suspending the target.

	 */

	wake_up(&cache->migration_wait);

	atomic_dec(&cache->nr_io_migrations);

}



static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
@@ -894,11 +910,10 @@ static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell, 
	wake_worker(cache);

}



static void cleanup_migration(struct dm_cache_migration *mg)

static void free_io_migration(struct dm_cache_migration *mg)

{

	struct cache *cache = mg->cache;

	dec_io_migrations(mg->cache);

	free_migration(mg);

	dec_nr_migrations(cache);

}



static void migration_failure(struct dm_cache_migration *mg)
@@ -923,7 +938,7 @@ static void migration_failure(struct dm_cache_migration *mg) 
		cell_defer(cache, mg->new_ocell, true);

	}



	cleanup_migration(mg);

	free_io_migration(mg);

}



static void migration_success_pre_commit(struct dm_cache_migration *mg)
@@ -934,7 +949,7 @@ static void migration_success_pre_commit(struct dm_cache_migration *mg) 
	if (mg->writeback) {

		clear_dirty(cache, mg->old_oblock, mg->cblock);

		cell_defer(cache, mg->old_ocell, false);

		cleanup_migration(mg);

		free_io_migration(mg);

		return;



	} else if (mg->demote) {
@@ -944,14 +959,14 @@ static void migration_success_pre_commit(struct dm_cache_migration *mg) 
					     mg->old_oblock);

			if (mg->promote)

				cell_defer(cache, mg->new_ocell, true);

			cleanup_migration(mg);

			free_io_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");

			policy_remove_mapping(cache->policy, mg->new_oblock);

			cleanup_migration(mg);

			free_io_migration(mg);

			return;

		}

	}
@@ -984,7 +999,7 @@ static void migration_success_post_commit(struct dm_cache_migration *mg) 
		} else {

			if (mg->invalidate)

				policy_remove_mapping(cache->policy, mg->old_oblock);

			cleanup_migration(mg);

			free_io_migration(mg);

		}



	} else {
@@ -999,7 +1014,7 @@ static void migration_success_post_commit(struct dm_cache_migration *mg) 
			bio_endio(mg->new_ocell->holder, 0);

			cell_defer(cache, mg->new_ocell, false);

		}

		cleanup_migration(mg);

		free_io_migration(mg);

	}

}
@@ -1251,7 +1266,7 @@ static void promote(struct cache *cache, struct prealloc *structs, 
	mg->new_ocell = cell;

	mg->start_jiffies = jiffies;



	inc_nr_migrations(cache);

	inc_io_migrations(cache);

	quiesce_migration(mg);

}
@@ -1275,7 +1290,7 @@ static void writeback(struct cache *cache, struct prealloc *structs, 
	mg->new_ocell = NULL;

	mg->start_jiffies = jiffies;



	inc_nr_migrations(cache);

	inc_io_migrations(cache);

	quiesce_migration(mg);

}
@@ -1302,7 +1317,7 @@ static void demote_then_promote(struct cache *cache, struct prealloc *structs, 
	mg->new_ocell = new_ocell;

	mg->start_jiffies = jiffies;



	inc_nr_migrations(cache);

	inc_io_migrations(cache);

	quiesce_migration(mg);

}
@@ -1330,7 +1345,7 @@ static void invalidate(struct cache *cache, struct prealloc *structs, 
	mg->new_ocell = NULL;

	mg->start_jiffies = jiffies;



	inc_nr_migrations(cache);

	inc_io_migrations(cache);

	quiesce_migration(mg);

}
@@ -1412,7 +1427,7 @@ static void process_discard_bio(struct cache *cache, struct prealloc *structs, 


static bool spare_migration_bandwidth(struct cache *cache)

{

	sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) *

	sector_t current_volume = (atomic_read(&cache->nr_io_migrations) + 1) *

		cache->sectors_per_block;

	return current_volume < cache->migration_threshold;

}
@@ -1764,7 +1779,7 @@ static void stop_quiescing(struct cache *cache) 


static void wait_for_migrations(struct cache *cache)

{

	wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations));

	wait_event(cache->migration_wait, !atomic_read(&cache->nr_allocated_migrations));

}



static void stop_worker(struct cache *cache)
@@ -1876,9 +1891,6 @@ static void destroy(struct cache *cache) 
{

	unsigned i;



	if (cache->next_migration)

		mempool_free(cache->next_migration, cache->migration_pool);



	if (cache->migration_pool)

		mempool_destroy(cache->migration_pool);
@@ -2424,7 +2436,8 @@ static int cache_create(struct cache_args *ca, struct cache **result) 
	INIT_LIST_HEAD(&cache->quiesced_migrations);

	INIT_LIST_HEAD(&cache->completed_migrations);

	INIT_LIST_HEAD(&cache->need_commit_migrations);

	atomic_set(&cache->nr_migrations, 0);

	atomic_set(&cache->nr_allocated_migrations, 0);

	atomic_set(&cache->nr_io_migrations, 0);

	init_waitqueue_head(&cache->migration_wait);



	init_waitqueue_head(&cache->quiescing_wait);
@@ -2487,8 +2500,6 @@ static int cache_create(struct cache_args *ca, struct cache **result) 
		goto bad;

	}



	cache->next_migration = NULL;



	cache->need_tick_bio = true;

	cache->sized = false;

	cache->invalidate = false;

drivers/md/dm.c

+7 −2
Original line number Diff line number Diff line
@@ -206,6 +206,9 @@ struct mapped_device { 
	/* zero-length flush that will be cloned and submitted to targets */

	struct bio flush_bio;



	/* the number of internal suspends */

	unsigned internal_suspend_count;



	struct dm_stats stats;

};
@@ -2928,7 +2931,7 @@ static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_fla 
{

	struct dm_table *map = NULL;



	if (dm_suspended_internally_md(md))

	if (md->internal_suspend_count++)

		return; /* nested internal suspend */



	if (dm_suspended_md(md)) {
@@ -2953,7 +2956,9 @@ static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_fla 


static void __dm_internal_resume(struct mapped_device *md)

{

	if (!dm_suspended_internally_md(md))

	BUG_ON(!md->internal_suspend_count);



	if (--md->internal_suspend_count)

		return; /* resume from nested internal suspend */



	if (dm_suspended_md(md))