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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 33C64C64E7A for ; Tue, 1 Dec 2020 03:51:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D6F2B20657 for ; Tue, 1 Dec 2020 03:51:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727593AbgLADvD (ORCPT ); Mon, 30 Nov 2020 22:51:03 -0500 Received: from sandeen.net ([63.231.237.45]:33174 "EHLO sandeen.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726151AbgLADvD (ORCPT ); Mon, 30 Nov 2020 22:51:03 -0500 Received: from liberator.sandeen.net (liberator.sandeen.net [10.0.0.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by sandeen.net (Postfix) with ESMTPSA id D30E9EDD; Mon, 30 Nov 2020 21:50:07 -0600 (CST) From: Eric Sandeen To: "Theodore Y. Ts'o" Cc: David Howells , "Darrick J. Wong" , linux-fsdevel@vger.kernel.org References: <20201125212523.GB14534@magnolia> <33d38621-b65c-b825-b053-eda8870281d1@sandeen.net> <1942931.1606341048@warthog.procyon.org.uk> <20201201032051.GK5364@mit.edu> Subject: Re: Clarification of statx->attributes_mask meaning? Message-ID: <56d406b1-b013-7711-2aa6-1ef9d3d5f5d4@sandeen.net> Date: Mon, 30 Nov 2020 21:50:21 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 11/30/20 9:37 PM, Eric Sandeen wrote: > On 11/30/20 9:20 PM, Theodore Y. Ts'o wrote: ... >> We should be really clear how applications are supposed to use the >> attributes_mask. Does it mean that they will always be able to set a >> flag which is set in the attribute mask? That can't be right, since >> there will be a number of flags that may have some more complex checks >> (you must be root, or the file must be zero length, etc.) I'm a bit >> unclear about what are the useful ways in which an attribute_mask can >> be used by a userspace application --- and under what circumstances >> might an application be depending on the semantics of attribute_mask, >> so we don't accidentally give them an opportunity to complain and >> whine, thus opening ourselves to another O_PONIES controversy. > > Hah, indeed. > > Sorry if I've over-complicated this, I'm honestly just confused now. hch warned us, I guess: https://lore.kernel.org/linux-fsdevel/20170404071252.GA30966@infradead.org/ At this point I guess I'll just set the dax attribute into the mask unconditionally for xfs, because xfs "supports" dax, and stop navel-gazing over this. -Eric