From 6221f1d9b63fed6260273e59a2b89ab30537a811 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 17 Apr 2020 12:40:31 -0400 Subject: SUNRPC: Fix backchannel RPC soft lockups Currently, after the forward channel connection goes away, backchannel operations are causing soft lockups on the server because call_transmit_status's SOFTCONN logic ignores ENOTCONN. Such backchannel Calls are aggressively retried until the client reconnects. Backchannel Calls should use RPC_TASK_NOCONNECT rather than RPC_TASK_SOFTCONN. If there is no forward connection, the server is not capable of establishing a connection back to the client, thus that backchannel request should fail before the server attempts to send it. Commit 58255a4e3ce5 ("NFSD: NFSv4 callback client should use RPC_TASK_SOFTCONN") was merged several years before RPC_TASK_NOCONNECT was available. Because setup_callback_client() explicitly sets NOPING, the NFSv4.0 callback connection depends on the first callback RPC to initiate a connection to the client. Thus NFSv4.0 needs to continue to use RPC_TASK_SOFTCONN. Suggested-by: Trond Myklebust Signed-off-by: Chuck Lever Cc: # v4.20+ --- net/sunrpc/svc_xprt.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/sunrpc/svc_xprt.c') diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index e27e3532ec75..92f2c08c67a5 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -1040,6 +1040,8 @@ static void svc_delete_xprt(struct svc_xprt *xprt) dprintk("svc: svc_delete_xprt(%p)\n", xprt); xprt->xpt_ops->xpo_detach(xprt); + if (xprt->xpt_bc_xprt) + xprt->xpt_bc_xprt->ops->close(xprt->xpt_bc_xprt); spin_lock_bh(&serv->sv_lock); list_del_init(&xprt->xpt_list); -- cgit