dm thin: fix inability to discard blocks when in out-of-data-space mode

When the pool was in PM_OUT_OF_SPACE mode its process_prepared_discard
function pointer was incorrectly being set to
process_prepared_discard_passdown rather than process_prepared_discard.

This incorrect function pointer meant the discard was being passed down,
but not effecting the mapping.  As such any discard that was issued, in
an attempt to reclaim blocks, would not successfully free data space.

Reported-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 8735543eacdb9ae0961ed841c3f8e81628100520..14b51a4fdf6b5635d6331e405763b158e272a094 100644 (file)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -2155,7 +2155,7 @@ static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
                pool->process_cell = process_cell_read_only;
                pool->process_discard_cell = process_discard_cell;
                pool->process_prepared_mapping = process_prepared_mapping;
-               pool->process_prepared_discard = process_prepared_discard_passdown;
+               pool->process_prepared_discard = process_prepared_discard;
 
                if (!pool->pf.error_if_no_space && no_space_timeout)
                        queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);