[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/linear.c b/drivers/md/linear.c
index 8d740013d74d..4991ba543368 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -238,6 +238,11 @@ static int linear_make_request (request_queue_t *q, struct bio *bio)
         dev_info_t *tmp_dev;
         sector_t block;
 
+        if (unlikely(bio_barrier(bio))) {
+                bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
+                return 0;
+        }
+
         if (bio_data_dir(bio)==WRITE) {
                 disk_stat_inc(mddev->gendisk, writes);
                 disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));