[CentOS] systemd automount of cifs share hangs

>
> Wait a minute: are you running IPv6? What we see is that if a system
> doesn't get its IPv6 address, NFSv4 goes preferentially for that, and if
> it has that, and looses it, it will *NOT* fall back to IPv4, but hangs.
>
> Nope.  My router does not do IPv6.  From what I've heard, the Myricom
driver was never updated for C7.  Myricom was acquired by some company
called CSPI, and apparently they're not interested in updating the driver.