[PATCH] md: fail IO request to md that require a barrier.

md does not yet support BIO_RW_BARRIER, so be honest about it and fail
(-EOPNOTSUPP) any such requests.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 2d2ca7fa0265..286342375fb7 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -169,6 +169,11 @@ static int multipath_make_request (request_queue_t *q, struct bio * bio)
         struct multipath_bh * mp_bh;
         struct multipath_info *multipath;
 
+        if (unlikely(bio_barrier(bio))) {
+                bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
+                return 0;
+        }
+
         mp_bh = mempool_alloc(conf->pool, GFP_NOIO);
 
         mp_bh->master_bio = bio;