The block device is backed by the transport so we must ensure that the
transport driver will not be removed until all references are released.
Otherwise, we might end up referencing freed memory.
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NNitzan Carmi <nitzanc@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>