From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63FB6C5ACC0 for ; Fri, 13 Mar 2020 17:55:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 367892074C for ; Fri, 13 Mar 2020 17:55:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="HyVxABY0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727046AbgCMRzd (ORCPT ); Fri, 13 Mar 2020 13:55:33 -0400 Received: from smtp-fw-9102.amazon.com ([207.171.184.29]:52348 "EHLO smtp-fw-9102.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726414AbgCMRzd (ORCPT ); Fri, 13 Mar 2020 13:55:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1584122134; x=1615658134; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=+IAf3wqqqLRqK3NTbkIrhUY5+LJxFuN34aCWNO1M0Vs=; b=HyVxABY0oElm4ke0KfBd1T69irV3DQNmYWYO+4rb/9xskcQdUUdkEULU Q0uNE+SHdDUxvbZZZ3T4boMgwNaGT7jDKRUr7NSE/4Uqe8xe73vXrWHVz k2KacO9fSUYrKUD9YqgeXgJjkuO71k9w7973EDuhyMRyCOxtgOZpbSHBN A=; IronPort-SDR: E98odBEbbxoB6CpZxbkA79UMyRomc6Ad5d454v/JN7aVoSVPu8apoYq+3uMYRrDAJ9FquK0cts WW41ZCnMeLJQ== X-IronPort-AV: E=Sophos;i="5.70,549,1574121600"; d="scan'208";a="31087707" Received: from sea32-co-svc-lb4-vlan3.sea.corp.amazon.com (HELO email-inbound-relay-1d-474bcd9f.us-east-1.amazon.com) ([10.47.23.38]) by smtp-border-fw-out-9102.sea19.amazon.com with ESMTP; 13 Mar 2020 17:55:31 +0000 Received: from EX13MTAUWA001.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan2.iad.amazon.com [10.40.159.162]) by email-inbound-relay-1d-474bcd9f.us-east-1.amazon.com (Postfix) with ESMTPS id 1C40CA2B12; Fri, 13 Mar 2020 17:55:30 +0000 (UTC) Received: from EX13D37UWA003.ant.amazon.com (10.43.160.25) by EX13MTAUWA001.ant.amazon.com (10.43.160.58) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Fri, 13 Mar 2020 17:55:29 +0000 Received: from EX13MTAUWA001.ant.amazon.com (10.43.160.58) by EX13D37UWA003.ant.amazon.com (10.43.160.25) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 13 Mar 2020 17:55:29 +0000 Received: from dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com (172.23.141.97) by mail-relay.amazon.com (10.43.160.118) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Fri, 13 Mar 2020 17:55:29 +0000 Received: by dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com (Postfix, from userid 6262777) id 91E22C13BA; Fri, 13 Mar 2020 17:55:29 +0000 (UTC) Date: Fri, 13 Mar 2020 17:55:29 +0000 From: Frank van der Linden To: Trond Myklebust CC: "tigran.mkrtchyan@desy.de" , "linux-nfs@vger.kernel.org" , "anna.schumaker@netapp.com" Subject: Re: [PATCH 03/13] NFSv4.2: query the server for extended attribute support Message-ID: <20200313175529.GB31307@dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com> References: <20200311195613.26108-1-fllinden@amazon.com> <20200311195613.26108-4-fllinden@amazon.com> <530167624.4533477.1584029710746.JavaMail.zimbra@desy.de> <20200312205139.GA32293@dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com> <20200312211555.GA5974@dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com> <948465413.4651196.1584097887947.JavaMail.zimbra@desy.de> <6792d6a6012a241b8bd1555eea8c592ff318a444.camel@hammerspace.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <6792d6a6012a241b8bd1555eea8c592ff318a444.camel@hammerspace.com> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Fri, Mar 13, 2020 at 01:50:38PM +0000, Trond Myklebust wrote: > 'xattr_support' seems like a protocol hack to allow the client to > determine whether or not the xattr operations are supported. > > The reason why it is a hack is that 'supported_attrs' is also a per- > filesystem attribute, and there is no value in advertising > 'xattr_support' there unless your filesystem also supports xattrs. > > IOW: the protocol forces you to do 2 round trips to the server in order > to figure out something that really should be obvious with 1 round > trip. Right, that's the annoying part. I mean, theoretically, a server can legally reject a GETATTR because you're asking for an unknown attribute (e.g. xattr_support in this case). So then what I have in my current patch (asking for both the supported_attrs and xattr_support at once) might fail, and the mount would fail. Which means I should split it up and have nfs4_do_fsinfo do the 2nd part, just in case. - Frank