drain_call_rcu is necessary on win32, because under win32, if you
don't close the file before remove it, the remove would be fail.
Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Message-Id: <20200915121318.247-23-luoyonggang@gmail.com> Signed-off-by: Thomas Huth <thuth@redhat.com>