commit d9771f5ec46c282d518b453c793635dbdc3a2a94 upstream.

commit d5d885fd ("md: introduce new personality funciton start()")
splits the init job to two parts. The first part run() does the jobs that
do not require the md threads. The second part start() does the jobs that
require the md threads.

Now it just does run() in adding new journal device. It needs to do the
second part start() too.

Fixes: d5d885fd ("md: introduce new personality funciton start()")
Cc: stable@vger.kernel.org #v4.9+
Reported-by: NMichal Soltys <soltys@ziu.info>
Signed-off-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>