[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/raid5.c b/drivers/md/raid5.c
index 43f231a467d5..ed859e08d600 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1411,6 +1411,11 @@ static int make_request (request_queue_t *q, struct bio * bi)
         sector_t logical_sector, last_sector;
         struct stripe_head *sh;
 
+        if (unlikely(bio_barrier(bi))) {
+                bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
+                return 0;
+        }
+
         md_write_start(mddev, bi);
 
         if (bio_data_dir(bi)==WRITE) {