From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2C9523DB636; Mon, 31 Aug 2026 12:05:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788177941; cv=none; b=Vj1e5flqlKl1e67+xL6Mg+egD+SZMeAkU6qpqvZ8eD5TjupNOaPsc3ivQlN51QT/F1c1mUPkn5VUacZsR8scZX+Uf0TVqerRnZ8PVpVSff5oUzMvPFI2A1a9DmGbfuUXch3r3xJRQyPMKKcVyXDqqDcJN1C6becmgdxdd2+5BsQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788177941; c=relaxed/simple; bh=tCK3/OlqomI9xjvtVhXAwUvs6ZD7l47RHKp+gAvqlPM=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=sBvL4QGNKU8vqnMrKpj15APNyvfVRQ3K9WP5lT2RYC0F7OvepM/O2CfGDdyj7Yjq7VbnBcBeA23lhlJkeFNHoCqb6qAUQaTWhP3/NEKdRRfYVioyI+r3Vcu7HzuIffGYT1jwwfdZT1oyhJJucxFxF/TBxjQblV4l2qY0iv95aag= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=koRVCYvn; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="koRVCYvn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 772641F000E9; Mon, 31 Aug 2026 12:05:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788177940; bh=eK4N+prxyq1UeFOdBDRTLJdmEzGIzVB4VhCDo8m8iy8=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=koRVCYvn52Sznk8s1vxJFxbuSYCxeDzWzA6P58fRF8JBFqoGzs/DEZyNIFSrW9Hwp E9YbxhJlVUhIlPm1PLXuXcd3tZT6yRNSLpaSVZvWouDKXe9dRbiwly0a+hHUbP8pWL n1FuAmJOtHQ/9TiO3xGMk7GqFHXT8Lwq3oMwbwhMe7zH0lN8XCGx4OXqf5DFDrQqNP KgKAp+wuicDiYbbceFQhkXq06oPWFM1kQNbPTUl52UzrDFTZToTb8hDSCCEFyumSm8 yc5Mbg2Tb9d24xc4djOCwPP0cm/Zy4oKJG/xgrTcUuNSHB8QMWaDA8OWpDm7Y2ySNk oD7dPTbu/VRxg== Message-ID: Subject: Re: [PATCH v3 06/14] SUNRPC: report local rpcbind calls that get no answer From: Jeff Layton To: Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , Trond Myklebust , Anna Schumaker , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Shuah Khan Cc: Slawomir Stepien , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Trond Myklebust , linux-kselftest@vger.kernel.org Date: Mon, 31 Aug 2026 08:05:37 -0400 In-Reply-To: References: <20260828-nfsd-nl-hang-v3-0-55026685c75d@kernel.org> <20260828-nfsd-nl-hang-v3-6-55026685c75d@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn 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Every call waits for the local rpcbind on its ow= n, > > so a rpcbind that never answers costs the caller one timeout per listen= er. > > The caller has no way to learn that the first call already failed. > >=20 > > 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. > >=20 > > Give the first case its own errno. rpcb_register_call() returns -ENAVAI= L > > when the call got no answer, and the existing -EACCES continues to mean= a > > FALSE reply. > >=20 > > 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, s= o a > > v4-only server still creates its listeners, and then keeps a running to= tal > > in serv->sv_rpcb_failures. -ENAVAIL never escapes svc_register(). > >=20 > > 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 bee= n > > errors. > >=20 > > The users of this infrastructure will be added in later patches. > >=20 > > Assisted-by: LLM > > Signed-off-by: Jeff Layton >=20 > > 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=20 > > *net, const char *nodename, > > return rpc_create(&args); > > } > >=20 > > -static int rpcb_register_call(struct sunrpc_net *sn, struct rpc_clnt= =20 > > *clnt, struct rpc_message *msg, bool is_set) > > +static int rpcb_register_call(struct sunrpc_net *sn, struct rpc_clnt= =20 > > *clnt, > > + struct rpc_message *msg, bool is_set) > > { > > int flags =3D RPC_TASK_NOCONNECT; > > int error, result =3D 0; > > @@ -422,8 +423,10 @@ static int rpcb_register_call(struct sunrpc_net= =20 > > *sn, struct rpc_clnt *clnt, stru > > msg->rpc_resp =3D &result; > >=20 > > error =3D rpc_call_sync(clnt, msg, flags); > > - if (error < 0) > > + if (error =3D=3D -EPROTONOSUPPORT) > > return error; > > + if (error < 0) > > + return -ENAVAIL; > >=20 > > if (!result) > > return -EACCES; >=20 > If I'm reading this correctly, rpcb_register_call() classifies > every failure except -EPROTONOSUPPORT as "no answer". >=20 > 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. >=20 > 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. >=20 > Consequences: >=20 > * 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. >=20 > * "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. >=20 > * -ERESTARTSYS -> -ETIMEDOUT drops syscall-restart semantics > on a fatal signal during registration. >=20 > I'm probably missing something. >=20 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. --=20 Jeff Layton