Hi Olga
On Fri, 2020-04-24 at 15:08 -0400, Olga Kornievskaia wrote:
> Currently, if the client sends BIND_CONN_TO_SESSION with
> NFS4_CDFC4_FORE_OR_BOTH but only gets NFS4_CDFS4_FORE back it ignores
> that it wasn't able to enable a backchannel.
>
> To make sure, the client sends BIND_CONN_TO_SESSION as the first
> operation on the connections (ie., no other session compounds haven't
> been sent before), and if the client's request to bind the
> backchannel
> is not satisfied, then reset the connection and retry.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx>
> ---
> fs/nfs/nfs4proc.c | 6 ++++++
> include/linux/sunrpc/clnt.h | 5 +++++
> 2 files changed, 11 insertions(+)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 512afb1..69a5487 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -7891,6 +7891,7 @@ static int nfs4_check_cl_exchange_flags(u32
> flags)
> nfs4_bind_one_conn_to_session_done(struct rpc_task *task, void
> *calldata)
> {
> struct nfs41_bind_conn_to_session_args *args = task-
> >tk_msg.rpc_argp;
> + struct nfs41_bind_conn_to_session_res *res = task-
> >tk_msg.rpc_resp;
> struct nfs_client *clp = args->client;
>
> switch (task->tk_status) {
> @@ -7899,6 +7900,11 @@ static int nfs4_check_cl_exchange_flags(u32
> flags)
> nfs4_schedule_session_recovery(clp->cl_session,
> task->tk_status);
> }
> + if (args->dir == NFS4_CDFC4_FORE_OR_BOTH &&
> + res->dir != NFS4_CDFS4_BOTH) {
> + rpc_task_close_connection(task);
> + task->tk_status = -NFS4ERR_DELAY;
We don't have any error handling for NFS4ERR_DELAY in this function, so
if your intention is to replay the RPC call, then maybe you want to
replace this line with a call to rpc_restart_call()?
However it would be good to ensure that we only do this once or twice
so that we don't loop forever. Maybe also add a variable to the struct
nfs41_bind_conn_to_session_args that can set the number of retries
remaining?
> + }
> }
>
> static const struct rpc_call_ops nfs4_bind_one_conn_to_session_ops =
> {
> diff --git a/include/linux/sunrpc/clnt.h
> b/include/linux/sunrpc/clnt.h
> index ca7e108..cc20a08 100644
> --- a/include/linux/sunrpc/clnt.h
> +++ b/include/linux/sunrpc/clnt.h
> @@ -236,4 +236,9 @@ static inline int rpc_reply_expected(struct
> rpc_task *task)
> (task->tk_msg.rpc_proc->p_decode != NULL);
> }
>
> +static inline void rpc_task_close_connection(struct rpc_task *task)
> +{
> + if (task->tk_xprt)
> + xprt_force_disconnect(task->tk_xprt);
> +}
> #endif /* _LINUX_SUNRPC_CLNT_H */
Thanks
Trond
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx
