Re: NFS root & shutdown/reboot

[Darren Hart <dvhart@linux.intel.com>]

On 04/15/2011 06:11 AM, Bruce Ashfield wrote:
> On Fri, Apr 15, 2011 at 8:29 AM, Paul Eggleton
> <paul.eggleton@linux.intel.com> wrote:
>> Hi all,
>>
>> I have been working on smoothing out some things to do with NFS root this week
>> and I have come across one situation that I'm not quite sure of.
>>
>> At the moment when you shut down a Poky NFS root-based system or reboot it, it
>> gets all the way to the end and then hangs, with an error "nfs: server
>> myserver not responding, still trying". I tracked this down to the -i option
>> that is passed to the final call to shutdown and reboot which is supposed to
>> shut down all network interfaces - if you remove this then it works fine.
>>
>> I'm not sure of the reason for having the -i option, but it was suggested to
>> me that it might be in order to release DHCP leases where applicable; also
>> some systems might otherwise leave their network adapters powered up when the
>> system is shut down in order to receive wake-on-LAN requests, and if you're
>> not using that feature you're just wasting power. I'm guessing for most
>> situations we would want to retain -i. However, where the system is running
>> from an NFS root it would seem that we would have to omit this option, unless
>> there is another solution I'm not aware of.
> 
> I can't say exactly when this is required either, but I can say that we've
> also removed -i from our NFS root boots in the past, for just what you
> are describing above.
> 
> Shutting down and getting the interface down in the wrong order causes
> the obvious problems you'd expect with a NFS root hanging and not
> being able to complete the rest of the process.
> 
>>
>> I've done some googling and not come up with anything concrete in terms of how
>> this should be handled correctly. Any suggestions?
> 
> My only suggestion is to make it not present by default, and enable
> it (-i) when a real reason for it is found (i.e. someone really wants
> the nic to shutdown for a power profile). Detecting a NFS root
> (and if the root continues to be NFS after boot) could be more error
> prone that making -i the default.
> 
> Just my opinion,
> 

Agreed. Perhaps this needs some kind of a machine config setting that
feeds into how shutdown is called, sort of like formfactor feeds into
matchbox?

--
Darren

> Bruce
> 
>>
>> Cheers,
>> Paul
>>
>> --
>>
>> Paul Eggleton
>> Intel Open Source Technology Centre (UK)
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>>
> 
> 
> 

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel