On Wed, 13 Nov 2013 20:48:04 +0000
Weston Andros Adamson <dros@xxxxxxxxxx> wrote:
> I tested v2 and everything looks good.
>
Thanks for testing it.
> Also, it seems like I’m no longer able to reproduce the "NFS: nfs4_discover_server_trunking unhandled error -512. Exiting with error EIO” dmesg.
>
> -dros
>
Interesting. I suspect that's due to the fact that we give up retrying
quickly enough now that you can't signal it fast enough there. It's
still probably reasonable to add in handling for -ERESTARTSYS in that
switch statement however. I imagine that it's still possible to race in
with a signal at the right time and trigger that message.
> On Nov 13, 2013, at 9:08 AM, Jeff Layton <jlayton@xxxxxxxxxx> 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.
> >
> > Note too that with this change, we don't need the (i > 2) check in the
> > -EACCES case since we now have a more reliable test as to whether we
> > should reattempt.
> >
> > Cc: stable@xxxxxxxxxxxxxxx # v3.10+
> > Cc: Chuck Lever <chuck.lever@xxxxxxxxxx>
> > Tested-by/Acked-by: Weston Andros Adamson <dros@xxxxxxxxxx>
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> > ---
> > fs/nfs/nfs4state.c | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
> > index c8e729d..6f04706 100644
> > --- a/fs/nfs/nfs4state.c
> > +++ b/fs/nfs/nfs4state.c
> > @@ -2093,10 +2093,15 @@ again:
> > nfs4_root_machine_cred(clp);
> > goto again;
> > }
> > - if (i > 2)
> > + if (clnt->cl_auth->au_flavor == RPC_AUTH_UNIX)
> > 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
> >
>
--
Jeff Layton <jlayton@xxxxxxxxxx>
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