Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx12.netapp.com ([216.240.18.77]:60862 "EHLO mx12.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754614Ab3KLWRo convert rfc822-to-8bit (ORCPT ); Tue, 12 Nov 2013 17:17:44 -0500 From: Weston Andros Adamson To: Jeff Layton CC: "Myklebust, Trond" , linux-nfs list , Chuck Lever Subject: Re: [PATCH] nfs: don't retry detect_trunking with RPC_AUTH_UNIX more than once Date: Tue, 12 Nov 2013 22:17:41 +0000 Message-ID: <6BD3F476-A74C-42FD-9A20-B8028BA26155@netapp.com> References: <1384291851-11154-1-git-send-email-jlayton@redhat.com> In-Reply-To: <1384291851-11154-1-git-send-email-jlayton@redhat.com> Content-Type: text/plain; charset="Windows-1252" MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: Tested-by/Acked-by: Weston Andros Adamson I can?t reproduce the BUG() with this patch applied. Besides the patch making complete sense to me, I have more evidence to back your explanation of the bug: Without this patch I can run a ton of mount/umounts and eventually hit the crash. Before the crash there will be *many* (10s of thousands) pipes in /var/lib/nfs/rpc_pipefs/nfs/, which kills gssd (too many fds). -dros On Nov 12, 2013, at 4:30 PM, Jeff Layton wrote: > Currently, when we try to mount and get back NFS4ERR_CLID_IN_USE or > NFS4ERR_WRONGSEC, we create a new rpc_clnt and then try the call again. > There is no guarantee that doing so will work however, so we can end up > retrying the call in an infinite loop. > > Worse yet, we create the new client using rpc_clone_client_set_auth, > which creates the new client as a child of the old one. Thus, we can end > up with a *very* long lineage of rpc_clnts. When we go to put all of the > references to them, we can end up with a long call chain that can smash > the stack as each rpc_free_client() call can recurse back into itself. > > This patch fixes this by simply ensuring that the SETCLIENTID call will > only be retried in this situation if the last attempt did not use > RPC_AUTH_UNIX. > > Cc: stable@vger.kernel.org # v3.10+ > Cc: Weston Andros Adamson > Cc: Chuck Lever > Signed-off-by: Jeff Layton > --- > fs/nfs/nfs4state.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c > index c8e729d..4c26c01 100644 > --- a/fs/nfs/nfs4state.c > +++ b/fs/nfs/nfs4state.c > @@ -2097,6 +2097,11 @@ again: > break; > case -NFS4ERR_CLID_INUSE: > case -NFS4ERR_WRONGSEC: > + /* No point in retrying if we already used RPC_AUTH_UNIX */ > + if (clnt->cl_auth->au_flavor == RPC_AUTH_UNIX) { > + status = -EPERM; > + break; > + } > clnt = rpc_clone_client_set_auth(clnt, RPC_AUTH_UNIX); > if (IS_ERR(clnt)) { > status = PTR_ERR(clnt); > -- > 1.8.3.1 >