CentOS - Aug 2015 - Shutdown hangs on "Unmounting NFS filesystems"

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.

Really, I don't think the problem is specific to WiFi.  I believe I'd
run into the same thing for any network connection that was not marked
"Available to all users" in NetworkManager.

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.

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

On 08/31/2015 05:22 AM, Dennis Jacobfeuerborn wrote:
> 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.
The problem occurs late in the shutdown sequence. There is no shell
available for entering a "kill" command.

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.