commit 5d17b4a4b7fa172b205be8a05051ae705d1dc3bb upstream.

This behaves just like sync_file_range(2) does.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>