[pulseaudio-discuss] Making locking nicer for NFS

[Colin Guthrie]

'Twas brillig, and David Henningsson at 03/04/12 06:54 did gyre and gimble:
> On 04/03/2012 06:27 AM, Arun Raghavan wrote:
>> On Thu, 2011-08-25 at 10:37 -0700, Thomas Bushnell, BSG wrote:
>>> This method also has the advantage of not relying on lock promotion
>>> semantics, which (apparently) will make the Windoze version easier.
>>>
>>>
>>> Thomas
>>>
>>> On Thu, Aug 25, 2011 at 10:30 AM, David Henningsson
>>> <david.henningsson at canonical.com>  wrote:
>>>          On 08/21/2011 04:38 PM, Thomas Bushnell, BSG wrote:
>>>                  Whoops. They need to repeat the read after obtaining
>>>                  the write lock and
>>>                  only update the file if the contents are still bad in
>>>                  that case.
>>>
>>>
>>>          Would a good handling of this be:
>>>
>>>          1) Open the cookie read-only
>>>          2) read the cookie
>>>          3) close file
>>>          4) if we have a correct cookie, do nothing more
>>>          5) if we have the wrong cookie, do the old handling unchanged:
>>>          open with write lock, check the contents (again), and write if
>>>          something is (still) wrong.
>>
>> Thomas, David: Any news on this? Looks like we're agreed on an approach
>> and this "just" needs to be implemented now. :)
> 
> As I understand it, Thomas problem was solved somehow (see
> https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/817269/comments/8
> ), and thus nobody did anything.
> 
> In the long term, maybe the cookie should move to XDG_RUNTIME_DIR [1],
> which I understand would normally reside on a tmpfs, where this is not
> an issue in the first place.

The runtime dir will only affect the native protocol socket (and other
unix sockets we create I guess) a related NFS fix I pushed the other day
as you know: https://bugs.freedesktop.org/show_bug.cgi?id=44680

It would not actually help with the .pulse-cookie file which was what
this thread started as.

So I think the general principle probably still stands here.

Col





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Colin Guthrie
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