[CentOS] Shutdown hangs on "Unmounting NFS filesystems"

[Dennis Jacobfeuerborn]

On 08/31/2015 02:15 AM, Robert Nichols wrote:
> On 08/30/2015 04:45 PM, John R Pierce wrote:
>> On 8/30/2015 2:20 PM, Robert Nichols wrote:
>>> Once the system gets into this state, the only remedy is a forced
>>> power-off.  What seems to be happening is that an NFS filesystem that
>>> auto-mounted over a WiFi connection cannot be unmounted because the
>>> WiFi connection is enabled only for my login and gets torn down when
>>> my UID is logged off.
>>>
>>> Any suggestions on how I can configure things to avoid this?  I
>>> really don't want to expose my WPA2 key by making the connection
>>> available to all users.
>>
>> my experience is A) NFS doesn't like unreliable networks, and B) WiFi
>> isn't very reliable.
>>
>> perhaps using the 'soft' mount option will help, along with intr ?
> 
> Making use of the "intr" option would require that the umount process
> have the console as its controlling tty.  AFAICT, having been invoked
> from the init process, it has _no_ controlling tty.  Hard to send a
> SIGINT that way.

The "intr" option is no longer available. See the nfs man page:
"This option is provided for backward compatibility.  It is ignored
after kernel 2.6.25."

You should be able to kill -9 the process though.

Regards,
  Dennis