fix #28871358

commit 944e7c87967c820a0f34a935b1f2799944099750 upstream

We need this for blk-mq to kick things into gear, if we told it that
we had more IO coming, but then failed to deliver on that promise.
Reviewed-by: NOmar Sandoval <osandov@fb.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>