Received: by 10.223.185.116 with SMTP id b49csp2392469wrg; Mon, 5 Mar 2018 01:58:57 -0800 (PST) X-Google-Smtp-Source: AG47ELthOa5Zx0kpK9bgCN8W5kVFyProRIJcb/YO1IXVigaPnZOw9WiWJGLrjqfO987T3SaENOZr X-Received: by 2002:a17:902:7c16:: with SMTP id x22-v6mr12543750pll.23.1520243937792; Mon, 05 Mar 2018 01:58:57 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1520243937; cv=none; d=google.com; s=arc-20160816; b=FvH62Wu/d6NLmsy6tOwxNezfzI4+tWaTPqtsBNpR63A/UAbDc63c/XnfvKkZ4mxAQO CCH+kYsf1VOtbHtLLLLGLkidTAwzkkuWlDTmCxfwWR4nXUAX3cROKxmb9dDeAa/dBhzr PE/A+KrgDP1/EDfN2A5PAppoEvGUqTKPk8T8UuacqoLq2zRCTbuDfcgvYYAaOUa/G58S 167eMZ1FrJAYvjm8nopCsrsU7mER4u/DCho5qbKaHlhZm1xjwhlKDiWKFOtSCy2A2k76 Ca52bNCENEWvTb4TxyexMTzCe/8Frc9AhIux/0YkDI4dNEKFP/ESvoh/GYHaMg33hUvb fYxg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:subject:message-id:date:from :references:in-reply-to:mime-version:arc-authentication-results; bh=c49xJTTKZYZOUsIzhGVCUGJmoYJsw4EJ6+TFk5F3V3w=; b=BtHRSWIFg0y0eWKh8Leum2ZTex9XG3XxDUFjhenvgAt+fhoUspjV0joGY5g6yMCXfF 3P7pzAqdI8cLshNp29YLyzctekO9l+hSPEzaeyKKLOrzE/PZPMF1MJtk6iKDm/IVKjNg HCzckMlrzQiRAfya8KqrRYHQqa/B411qYI8D1a6dE5ZUBu0KRPvKOA+rvlAtMjtZZjZM kgPXgbOLvRzVShSJwKJGKyQMbC1KPMNGpd+1Yvu8i9gCwfZX6nk4HlLoWqqOPpD4De4D uHTmLN9Pg2dR2Ou4414CDsegMJjFo2RZGAekjKtC6EiV6uACHmGFKI0AlNUdsjcHEe7L XMCw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id t13si8111037pgp.450.2018.03.05.01.58.43; Mon, 05 Mar 2018 01:58:57 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933811AbeCEJxq (ORCPT + 99 others); Mon, 5 Mar 2018 04:53:46 -0500 Received: from mail-qt0-f182.google.com ([209.85.216.182]:38960 "EHLO mail-qt0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933071AbeCEJxm (ORCPT ); Mon, 5 Mar 2018 04:53:42 -0500 Received: by mail-qt0-f182.google.com with SMTP id n9so4741213qtk.6 for ; Mon, 05 Mar 2018 01:53:42 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=c49xJTTKZYZOUsIzhGVCUGJmoYJsw4EJ6+TFk5F3V3w=; b=R677io26frA3YvL/mxwLgfkanzyqRfWzWvnvxZRFGhcexB+4OCh8mduargQOJvQRgu jn0+3UgXWKu98WS5s2A3q+kcwRQKXuEVZwZ/6EHqy1K4zTEnMPFVbY4vgB1QDwKHQ3ID sIsttU6mpM/22egg7FumBkYZ9JZF9jhNwZNY62p+/F+uJn4t86Q1ESu2NttP2assk3H2 NzJfBrPSucmcYbzlhziVu8S84iYAXEYUgs2gfd7pBS5bdH2tV8pWyx6HBdiQ/oNK1+zA MspGdXCHxqZTQ74PR3ftC9gxGROI48h3i3ePFcENDBFQPPyORC7PO7v6iDK+3nbxkDfD sqtw== X-Gm-Message-State: AElRT7H4jOMDnah8biO26NTefYpr7CtyOBTY4/yRfJVYzjKrbiNXhTh3 BEBqfZwZj2PVlyFoiuyuCan9wnOOlZNtQCa9CdZZotci X-Received: by 10.237.63.220 with SMTP id w28mr22584362qth.312.1520243621876; Mon, 05 Mar 2018 01:53:41 -0800 (PST) MIME-Version: 1.0 Received: by 10.140.29.117 with HTTP; Mon, 5 Mar 2018 01:53:41 -0800 (PST) In-Reply-To: <20180302215919.27207-1-ebiederm@xmission.com> References: <87r2p287i8.fsf_-_@xmission.com> <20180302215919.27207-1-ebiederm@xmission.com> From: Miklos Szeredi Date: Mon, 5 Mar 2018 10:53:41 +0100 Message-ID: Subject: Re: [PATCH v8 1/6] fs/posix_acl: Update the comments and support lightweight cache skipping To: "Eric W. Biederman" Cc: lkml , Linux Containers , linux-fsdevel , Alban Crequy , Seth Forshee , Sargun Dhillon , Dongsu Park , "Serge E. Hallyn" , Linus Torvalds Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 2, 2018 at 10:59 PM, Eric W. Biederman wrote: > The code has been missing a way for a ->get_acl method to not cache > a return value without risking invalidating a cached value > that was set while get_acl() was returning. > > Add that support by implementing to_uncachable_acl, to_cachable_acl, > is_uncacheable_acl, and dealing with uncachable acls in get_acl(). I don't like the pointer magic here. Can't the uncachable bit just be added to struct posix_acl? AFAICS that can be done even without increasing the size of that struct (e.g. by unioning it with the rcu_head). Thanks, Miklos