On Sun, 2026-08-30 at 11:51 -0400, Chuck Lever wrote: > > On Fri, Aug 28, 2026, at 12:37 PM, Jeff Layton wrote: > > A caller that creates many listeners in one operation calls svc_register() > > once for each of them. Every call waits for the local rpcbind on its own, > > so a rpcbind that never answers costs the caller one timeout per listener. > > The caller has no way to learn that the first call already failed. > > > > An rpcbind failure can occur one of two ways: either rpcbind fails to > > respond, or it can respond with -EACCES to indicate that the user > > doesn't own the current record. > > > > Give the first case its own errno. rpcb_register_call() returns -ENAVAIL > > when the call got no answer, and the existing -EACCES continues to mean a > > FALSE reply. > > > > svc_generic_rpcbind_set() has to let -ENAVAIL past vs_rpcb_optnl, since it > > is not a refusal. svc_register() applies vs_rpcb_optnl to it instead, so a > > v4-only server still creates its listeners, and then keeps a running total > > in serv->sv_rpcb_failures. -ENAVAIL never escapes svc_register(). > > > > svc_rpcb_failure_count() reports the total. A caller reads the count > > before it starts and compares as it goes to determine if there have been > > errors. > > > > The users of this infrastructure will be added in later patches. > > > > Assisted-by: LLM > > Signed-off-by: Jeff Layton <[email protected]> > > > diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c > > index 0aa376b82a52..c680137f0fca 100644 > > --- a/net/sunrpc/rpcb_clnt.c > > +++ b/net/sunrpc/rpcb_clnt.c > > @@ -412,7 +412,8 @@ static struct rpc_clnt *rpcb_create(struct net > > *net, const char *nodename, > > return rpc_create(&args); > > } > > > > -static int rpcb_register_call(struct sunrpc_net *sn, struct rpc_clnt > > *clnt, struct rpc_message *msg, bool is_set) > > +static int rpcb_register_call(struct sunrpc_net *sn, struct rpc_clnt > > *clnt, > > + struct rpc_message *msg, bool is_set) > > { > > int flags = RPC_TASK_NOCONNECT; > > int error, result = 0; > > @@ -422,8 +423,10 @@ static int rpcb_register_call(struct sunrpc_net > > *sn, struct rpc_clnt *clnt, stru > > msg->rpc_resp = &result; > > > > error = rpc_call_sync(clnt, msg, flags); > > - if (error < 0) > > + if (error == -EPROTONOSUPPORT) > > return error; > > + if (error < 0) > > + return -ENAVAIL; > > > > if (!result) > > return -EACCES; > > If I'm reading this correctly, rpcb_register_call() classifies > every failure except -EPROTONOSUPPORT as "no answer". > > rpc_call_sync() returns negative errnos that are not "no answer": > pre-dispatch local failures (-ENOMEM from rpc_new_task()), a fatal > signal (-ERESTARTSYS), and reply-derived errors from > rpc_verify_header(): -EPFNOSUPPORT, -EOPNOTSUPP, -EIO, -EACCES > (auth error), -EKEYREJECTED. All of these show that rpcbind *did* > answer. > > Now they become -ENAVAIL, get counted in sv_rpcb_failures, are > silently converted to success for a vs_rpcb_optnl version, and > reach userspace as a synthesized -ETIMEDOUT for mandatory versions. > > Consequences: > > * The commit message says "-EACCES continues to mean a FALSE > reply," but the RPC layer's auth -EACCES is rewritten to > -ENAVAIL before the two can be told apart. Its "one of two > ways" failure taxonomy is not what the code implements. > > * "rpcbind not running" (-ECONNREFUSED/-ENOENT) and every > other transport error reach nfsd's listener_set ack, the > svc_register/svc_unregister tracepoints, and the printk > as indistinguishable ETIMEDOUT/ENAVAIL, which IMO is an > observability regression. > > * -ERESTARTSYS -> -ETIMEDOUT drops syscall-restart semantics > on a fatal signal during registration. > > I'm probably missing something. >
Fair point. I've mostly been trying to classify errors as to whether there is any point is attempting further registrations. For most of the errors besides -EACCES (aka rpc_auth_error), there is no point. That said, I've gone in an cleaned up the error handling here, so v4 should be a bit more explicit about how errors are handled. -- Jeff Layton <[email protected]>
