On Fri, 2023-04-07 at 20:30 -0700, Dai Ngo wrote:
> Currently call_bind_status places a hard limit of 9 seconds for retries
> on EACCES error. This limit was done to prevent the RPC request from
> being retried forever if the remote server has problem and never comes
> up
>
> However this 9 seconds timeout is too short, comparing to other RPC
> timeouts which are generally in minutes. This causes intermittent failure
> with EIO on the client side when there are lots of NLM activity and the
> NFS server is restarted.
>
> Instead of removing the max timeout for retry and relying on the RPC
> timeout mechanism to handle the retry, which can lead to the RPC being
> retried forever if the remote NLM service fails to come up. This patch
> simply increases the max timeout of call_bind_status from 9 to 90 seconds
> which should allow enough time for NLM to register after a restart, and
> not retrying forever if there is real problem with the remote system.
>
> Fixes: 0b760113a3a1 ("NLM: Don't hang forever on NLM unlock requests")
> Reported-by: Helen Chao <helen.chao@xxxxxxxxxx>
> Tested-by: Helen Chao <helen.chao@xxxxxxxxxx>
> Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
> ---
> include/linux/sunrpc/clnt.h | 3 +++
> include/linux/sunrpc/sched.h | 4 ++--
> net/sunrpc/clnt.c | 2 +-
> net/sunrpc/sched.c | 3 ++-
> 4 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
> index 770ef2cb5775..81afc5ea2665 100644
> --- a/include/linux/sunrpc/clnt.h
> +++ b/include/linux/sunrpc/clnt.h
> @@ -162,6 +162,9 @@ struct rpc_add_xprt_test {
> #define RPC_CLNT_CREATE_REUSEPORT (1UL << 11)
> #define RPC_CLNT_CREATE_CONNECTED (1UL << 12)
>
> +#define RPC_CLNT_REBIND_DELAY 3
> +#define RPC_CLNT_REBIND_MAX_TIMEOUT 90
> +
> struct rpc_clnt *rpc_create(struct rpc_create_args *args);
> struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *,
> const struct rpc_program *, u32);
> diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
> index b8ca3ecaf8d7..e9dc142f10bb 100644
> --- a/include/linux/sunrpc/sched.h
> +++ b/include/linux/sunrpc/sched.h
> @@ -90,8 +90,8 @@ struct rpc_task {
> #endif
> unsigned char tk_priority : 2,/* Task priority */
> tk_garb_retry : 2,
> - tk_cred_retry : 2,
> - tk_rebind_retry : 2;
> + tk_cred_retry : 2;
> + unsigned char tk_rebind_retry;
> };
>
> typedef void (*rpc_action)(struct rpc_task *);
> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> index fd7e1c630493..222578af6b01 100644
> --- a/net/sunrpc/clnt.c
> +++ b/net/sunrpc/clnt.c
> @@ -2053,7 +2053,7 @@ call_bind_status(struct rpc_task *task)
> if (task->tk_rebind_retry == 0)
> break;
> task->tk_rebind_retry--;
> - rpc_delay(task, 3*HZ);
> + rpc_delay(task, RPC_CLNT_REBIND_DELAY * HZ);
> goto retry_timeout;
> case -ENOBUFS:
> rpc_delay(task, HZ >> 2);
> diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
> index be587a308e05..5c18a35752aa 100644
> --- a/net/sunrpc/sched.c
> +++ b/net/sunrpc/sched.c
> @@ -817,7 +817,8 @@ rpc_init_task_statistics(struct rpc_task *task)
> /* Initialize retry counters */
> task->tk_garb_retry = 2;
> task->tk_cred_retry = 2;
> - task->tk_rebind_retry = 2;
> + task->tk_rebind_retry = RPC_CLNT_REBIND_MAX_TIMEOUT /
> + RPC_CLNT_REBIND_DELAY;
>
> /* starting timestamp */
> task->tk_start = ktime_get();
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
