We only need the stats lock (aka preempt_disable()) for updating the
states, not for looking up or dropping the hd_struct reference.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: NJens Axboe <axboe@kernel.dk>