Commit 4df99e3c authored Nov 27, 2014 by Joe Thornber Committed by Greg Kroah-Hartman Jan 08, 2015

dm cache: only use overwrite optimisation for promotion when in writeback mode



commit f29a3147e251d7ae20d3194ff67f109d71e501b4 upstream.

Overwrite causes the cache block and origin blocks to diverge, which
is only allowed in writeback mode.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 6425e7b0

drivers/md/dm-cache-target.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1070,7 +1070,8 @@ static void issue_copy(struct dm_cache_migration *mg)

		avoid = is_discarded_oblock(cache, mg->new_oblock);

		if (!avoid && bio_writes_complete_block(cache, bio)) {
		if (writeback_mode(&cache->features) &&
		!avoid && bio_writes_complete_block(cache, bio)) {
		issue_overwrite(mg, bio);
		return;
		}