virtio-blk: allow toggling host cache between writeback and writethrough

[firefly-linux-kernel-4.4.55.git] / drivers / md / dm-thin.c

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index ce59824fb41401963113a17af05ac660954bbef2..68694da0d21d0566a61649339cb3a4f3a3bbc943 100644 (file)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1245,7 +1245,10 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
 
                        cell_release_singleton(cell, bio);
                        cell_release_singleton(cell2, bio);
-                       remap_and_issue(tc, bio, lookup_result.block);
+                       if ((!lookup_result.shared) && pool->pf.discard_passdown)
+                               remap_and_issue(tc, bio, lookup_result.block);
+                       else
+                               bio_endio(bio, 0);
                }
                break;
 
@@ -2628,6 +2631,7 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
        if (tc->pool->pf.discard_enabled) {
                ti->discards_supported = 1;
                ti->num_discard_requests = 1;
+               ti->discard_zeroes_data_unsupported = 1;
        }
 
        dm_put(pool_md);