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Commit 4d1662a3 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm thin: avoid metadata commit if a pool's thin devices haven't changed 



Commit 905e51b3 ("dm thin: commit outstanding data every second")
introduced a periodic commit.  This commit occurs regardless of whether
any thin devices have made changes.

Fix the periodic commit to check if any of a pool's thin devices have
changed using dm_pool_changed_this_transaction().

Reported-by: default avatarAlexander Larsson <alexl@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Acked-by: default avatarJoe Thornber <ejt@redhat.com>
Cc: stable@vger.kernel.org
parent 80ae49aa

drivers/md/dm-thin-metadata.c

+17 −0
Original line number Diff line number Diff line
@@ -1489,6 +1489,23 @@ bool dm_thin_changed_this_transaction(struct dm_thin_device *td) 
	return r;

}



bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd)

{

	bool r = false;

	struct dm_thin_device *td, *tmp;



	down_read(&pmd->root_lock);

	list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {

		if (td->changed) {

			r = td->changed;

			break;

		}

	}

	up_read(&pmd->root_lock);



	return r;

}



bool dm_thin_aborted_changes(struct dm_thin_device *td)

{

	bool r;

drivers/md/dm-thin-metadata.h

+2 −0
Original line number Diff line number Diff line
@@ -161,6 +161,8 @@ int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block); 
 */

bool dm_thin_changed_this_transaction(struct dm_thin_device *td);



bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd);



bool dm_thin_aborted_changes(struct dm_thin_device *td);



int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,

drivers/md/dm-thin.c

+2 −1
Original line number Diff line number Diff line
@@ -1357,7 +1357,8 @@ static void process_deferred_bios(struct pool *pool) 
	bio_list_init(&pool->deferred_flush_bios);

	spin_unlock_irqrestore(&pool->lock, flags);



	if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))

	if (bio_list_empty(&bios) &&

	    !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))

		return;



	if (commit(pool)) {