Re: NFS sillyrename side effect

[Ian Munsie <imunsie-8fk3Idey6ehBDgjK7y7TUQ@public.gmane.org>]

Hi all,

Excerpts from Jeff Layton's message of Tue Oct 19 01:10:59 +1100 2010:
> See:
> 
> http://nfs.sourceforge.net/
> 
> ...section D2. The faq mentions that NFSv4 could do away with it
> because it's stateful, but that's not really the case either.

Thanks for the pointer.

> > It seems to me that if the sillyrename function is indeed necessary that
> > we should not reveal the temporary filename it produces to userspace,
> > but I wonder if that might create issues (say if userspace thinks a
> > directory is empty when it acutally has a sillyrename file in it)?
> > 
> > Basically I want to know if the behaviour I've outlined below is
> > the expected behaviour of NFS, or if you considder this a bug?
> > 
> 
> 
> It's expected. Sillyrenaming sucks, but there really is no great
> alternative to it. It's one of the prices we pay for having NFSv2/3 be
> stateless.
> 
> I suppose in principle we could do things like hide silly-renamed
> dentries from userspace, but that might also be problematic. You'd
> still be unable to remove a directory that has a silly-renamed file in
> it, for instance even though it looks empty. There would also be
> inconsistencies as other machines and the server would still see
> the .nfsXXXXX files.

I had a feeling that would be the case.

> The bottom line is that you need to be really careful with programs
> that use delete-on-last-close when running on NFS.


Thanks to everyone who replied for clarifying this matter for me.

Cheers,
-Ian