dm mpath: enable WRITE SAME support

Enable WRITE SAME support in dm multipath.  As far as multipath is
concerned it is just another write request.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Tested-by: Bharata B Rao <bharata.rao@gmail.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 51bb81676be37d2ff4520557c70f83bda488845a..bdf26f5bd326011595f8b9801cc2e408af6842cc 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -907,6 +907,7 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
 
        ti->num_flush_bios = 1;
        ti->num_discard_bios = 1;
+       ti->num_write_same_bios = 1;
 
        return 0;