Re: [PATCH v2] NFSv4: Save the owner/group name string when doing open

[Trond Myklebust <Trond.Myklebust@netapp.com>]

On Sat, 2012-01-07 at 18:13 -0500, Chuck Lever wrote: 
> On Jan 7, 2012, at 1:27 PM, Trond Myklebust wrote:
> 
> > ...so that we can do the uid/gid mapping outside the asynchronous RPC
> > context.
> > This fixes a bug in the current NFSv4 atomic open code where the client
> > isn't able to determine what the true uid/gid fields of the file are,
> > (because the asynchronous nature of the OPEN call denies it the ability
> > to do an upcall) and so fills them with default values, marking the
> > inode as needing revalidation.
> > Unfortunately, in some cases, the VFS will do some additional sanity
> > checks on the file, and may override the server's decision to allow
> > the open because it sees the wrong owner/group fields.
> 
> I expect this change would also address the known problem with empty application core dumps on NFSv4 mounts...?

Yes. I believe that the above mentioned VFS-level checks were the
problem there.


-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com