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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 E47CCC33C9E for ; Tue, 7 Jan 2020 17:44:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB90A2072A for ; Tue, 7 Jan 2020 17:44:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="P/XrLA3s" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728459AbgAGRoL (ORCPT ); Tue, 7 Jan 2020 12:44:11 -0500 Received: from mail-wr1-f68.google.com ([209.85.221.68]:34388 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728344AbgAGRoK (ORCPT ); Tue, 7 Jan 2020 12:44:10 -0500 Received: by mail-wr1-f68.google.com with SMTP id t2so424576wrr.1 for ; Tue, 07 Jan 2020 09:44:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chrisdown.name; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=8eqMnrGTPiMzUvhdb0Z8uXo41jdrtgsf6hpzBK0nlMQ=; b=P/XrLA3sWbGycnyupfzOxWdJivC6ceAXPPCxrnLUPh+TduZx5ndkDZmQXFSHrof9j/ tQD9SaAE/CdOr3P0R5dH+i1X2R95TWzLK/Jp8GKp77O7/YBGVPPkFEYnAgDIzrogEDyu S+xg3zJZWVZX3XvTEenCiAzsGCh+QTqRMY1+o= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=8eqMnrGTPiMzUvhdb0Z8uXo41jdrtgsf6hpzBK0nlMQ=; b=bh3nLgLhCbyxkknSQ7KQnVVd6IiPn+vw0CQ+6yNKO7RxqfpLntb5O+rXBEweQcfv8F ryZUZxBc9Vr5TxwKCgqdX9Yx4STllzWYOYLlGJ9UND2//CTfHuIm35JJocfLiqjb0uSU ig8j5ZHxDqWqXeBEbzdDlxTLJXyWsNFRbYKx8ZUlis8LG/QriO4xkalLxADmmm6bOpwJ AHbCQVyZjSOm1dVcWr4+EAi/WLt35PZglUK9PL12wiY/XgNO21UvkbDbYzMvQN8Ta7Me 1hxvoj95ZeeFmatWUkLJxMTVyl0fXGD3ACGu1h/tgoN8EcsyWNTPz/i5sI7qmtQ0LR8B e/vw== X-Gm-Message-State: APjAAAUPp6MumSVm2rhnVrBczAimc8GH6aSVJtO7RLnGCCXCPLJHo9O3 zBYLix+3zen1Z71Psc1RfTI3xQ== X-Google-Smtp-Source: APXvYqynyqHQyph7mlkfkGczhahKEDtFTIiSOiCq7anm6rJZZrYX1taZ671LNRgmt2SgYo6hlDdfDg== X-Received: by 2002:adf:82f3:: with SMTP id 106mr225820wrc.69.1578419048428; Tue, 07 Jan 2020 09:44:08 -0800 (PST) Received: from localhost ([2620:10d:c092:180::1:2344]) by smtp.gmail.com with ESMTPSA id u1sm413118wmc.5.2020.01.07.09.44.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Jan 2020 09:44:08 -0800 (PST) Date: Tue, 7 Jan 2020 17:44:07 +0000 From: Chris Down To: "J. Bruce Fields" Cc: "Darrick J. Wong" , linux-fsdevel@vger.kernel.org, Al Viro , Jeff Layton , Johannes Weiner , Tejun Heo , linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH] fs: inode: Reduce volatile inode wraparound risk when ino_t is 64 bit Message-ID: <20200107174407.GA666424@chrisdown.name> References: <20191220024936.GA380394@chrisdown.name> <20191220213052.GB7476@magnolia> <20191221101652.GA494948@chrisdown.name> <20200107173530.GC944@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20200107173530.GC944@fieldses.org> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org J. Bruce Fields writes: >I thought that (dev, inum) was supposed to be unique from creation to >last unlink (and last close), and (dev, inum, generation) was supposed >to be unique for all time. Sure, but I mean, we don't really protect against even the first case. >> I didn't mention generation because, even though it's set on tmpfs >> (to prandom_u32()), it's not possible to evaluate it from userspace >> since `ioctl` returns ENOTTY. We can't ask userspace applications to >> introspect on an inode attribute that they can't even access :-) > >Is there any reason not to add IOC_GETVERSION support to tmpfs? > >I wonder if statx should return it too? We can, but that seems like a tangential discussion/patch series. For the second case especially, that's something we should do separately from this patchset, since this demonstrably fixes issues encountered in production, and extending a user-facing APIs is likely to be a much more extensive discussion. (Also, this one in particular has advanced quite a lot since this v1 patch :-))