[Sheepdog] Some setattr/getattr strangeness

[MORITA Kazutaka]

At Thu, 13 Oct 2011 15:52:56 +0100,
Chris Webb wrote:
> 
> MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp> writes:
> 
> > Chris Webb wrote:
> >
> > > Hi Kazutaka. Just double-checking, but is there a race here where the id is
> > > allocated but the key isn't written yet, i.e. a getattr on another host
> > > could see a value for the attribute but that value is an empty string
> > > because the new object hasn't been written?
> > 
> > Yes, there is...  I believe this is the reason you got the empty
> > attribute.  I'll fix it.
> > 
> > Should setattr without '-x' also work atomically?  For example,
> > multiple hosts may send setattr against the same existing attribute at
> > the same time?  Currently, this operation can cause replication
> > inconsistency.
> 
> I don't rely on this myself at present, but it's probably the sort of thing
> that would surprise other integrators in future, so I think I'd be tempted
> to make them both atomic if that's not very difficult?

It is not so difficult though it requires a bit more changes.  Okay,
I'll make them both atomic operations. :)
Thanks for your comments.

Kazutaka