Re: [PATCH v5 3/7] nfsd: only check RPC_SIGNALLED() when restarting rpc_task

From: Chuck Lever
Date: Sat Feb 08 2025 - 11:59:54 EST


On 2/7/25 4:53 PM, Jeff Layton wrote:
> nfsd4_cb_sequence_done() currently checks RPC_SIGNALLED() when
> processing the compound and releasing the slot. If RPC_SIGNALLED()
> returns true, then that means that the client is going to be torn down.
>
> Don't check RPC_SIGNALLED() after processing a successful reply.
> Instead, only check that before restarting the rpc_task. If that returns
> true, then requeue the callback.

This might seem like a nit, but this paragraph didn't make sense to me
at all until I changed s/only check that before/check that only before/.


> Also, handle rpc_restart_call() and rpc_restart_call_prepare() failures
> correctly, by requeueing the callback.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/nfsd/nfs4callback.c | 18 ++++++++++--------
> 1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
> index bb5356e8713a8840bb714859618ff88130825efd..1e601075fac02bd5f01ff89d9252ab23d08c4fd9 100644
> --- a/fs/nfsd/nfs4callback.c
> +++ b/fs/nfsd/nfs4callback.c
> @@ -1385,8 +1385,8 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
> goto requeue;
> case -NFS4ERR_DELAY:
> cb->cb_seq_status = 1;
> - if (!rpc_restart_call(task))
> - goto out;
> + if (RPC_SIGNALLED(task) || !rpc_restart_call(task))
> + goto requeue;
> rpc_delay(task, 2 * HZ);
> return false;
> case -NFS4ERR_BADSLOT:
> @@ -1402,14 +1402,16 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
> }
> trace_nfsd_cb_free_slot(task, cb);
> nfsd41_cb_release_slot(cb);
> -
> - if (RPC_SIGNALLED(task))
> - goto requeue;
> -out:
> return ret;
> retry_nowait:
> - rpc_restart_call_prepare(task);
> - goto out;
> + /*
> + * RPC_SIGNALLED() means that the rpc_client is being torn down and
> + * (possibly) recreated. Requeue the call in that case.
> + */
> + if (!RPC_SIGNALLED(task)) {
> + if (rpc_restart_call_prepare(task))
> + return false;
> + }
> requeue:
> nfsd41_cb_release_slot(cb);
> if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
>


--
Chuck Lever