Re: 2.6.21.3: NFS: Buggy server - nlink == 0!

[Ravikiran G Thirumalai <kiran@scalex86.org>]

On Wed, Jun 06, 2007 at 08:33:17AM -0400, Trond Myklebust wrote:
> On Wed, 2007-06-06 at 12:25 +0200, Peter =C5strand wrote:
> > On Wed, 6 Jun 2007, Ravikiran G Thirumalai wrote:
> > =

> > > While running a dbench stress test on  a nfs mounted file system, I n=
otice
> > > the subject error message on the client machine.  The client machine =
is a 48
> > > core box with NUMA characteristics and 1024 dbench processes running
> > > continuously in a loop, while another memory hog application runs in =
parallel.
> > > The client is on 2.6.21.3.  The server is booted up with 2.6.21.3 as =
well.
> > > Attached is the server configuration.  Same test on a 2.6.16 client d=
oes not
> > > spew out these messages.  Is this really the server issue, or is the =
NFS
> > > client to be blamed here?
> > =

> > I've seen this message with the unfs3 server as well, and it contains s=
ome =

> > explicit checks to avoid sending nlink=3D0. So this is another indicati=
on =

> > that this is actually a client problem.
> =

> Feel free to send a tcpdump to prove it. So far all cases I've ever seen
> of this error message have been servers sending crap back for LOOKUP
> calls. The client does not ever modify the struct nfs_fattr after it has
> decoded the server reply.

I think Trond is right.  I tried the same test with the server running
mainline 2.6.18, and I did not see these error messages on the client.  This
seems to be a regression in the 2.6.21 nfs server code.

Thanks,
Kiran

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