[sheepdog] [PATCH 3/3] plain_store: store stale objects in .stale/[epoch]/

[Liu Yuan]

On 08/26/2012 06:50 PM, MORITA Kazutaka wrote:
> This is necessary to pass test 034.
> 
> Storing stale objects in a flat directory causes a problem.  It is
> because if the objects are updated while leaving cluster, sheep cannot
> detect it and uses the local stale objects as the latest one.  It is
> mandatory to store stale objects with epoch information like old farm
> code or simple store.
> 
> This patch create a epoch directory like simple store.  I think this
> is the simplest way to store stale objects with epoch info.

I am actually doing the same problem. I have thought of this approach, but I come 
up with another one, instead of use [epoch]/oid to tag the stale object, I just play
with its name to store stale objects:

  .stale/oid.epoch

My patch is finished but still can't pass the updated 028.

The problem your patch set don't handle is: for default_read(), when iocb.epoch < sys_epoch()
we need read upwards like Farm did to fix subtle problems found in multiple node change events.

I'm going to test your current devel branch against updated 028.

Thanks,
Yuan