dm: zero silently drop discards

Have the zero target silently drop a discard rather than fail the
request with -EOPNOTSUPP.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c
index bbc9703..cc2b3cb 100644 (file)
--- a/drivers/md/dm-zero.c
+++ b/drivers/md/dm-zero.c
@@ -22,6 +22,11 @@ static int zero_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                return -EINVAL;
        }
 
+       /*
+        * Silently drop discards, avoiding -EOPNOTSUPP.
+        */
+       ti->num_discard_requests = 1;
+
        return 0;
 }