The original commit missed this function, it needs to mark it a
write flush.
Cc: Mike Christie <mchristi@redhat.com>
Fixes: e742fc32fcb4 ("target: use bio op accessors")
Signed-off-by: Jens Axboe <axboe@fb.com>
        bio = bio_alloc(GFP_KERNEL, 0);
        bio->bi_end_io = iblock_end_io_flush;
        bio->bi_bdev = ib_dev->ibd_bd;
-       bio->bi_rw = WRITE_FLUSH;
+       bio_set_op_attrs(bio, REQ_OP_WRITE, WRITE_FLUSH);
        if (!immed)
                bio->bi_private = cmd;
        submit_bio(bio);