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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0D39C433F5 for ; Mon, 14 Mar 2022 21:08:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245216AbiCNVKH (ORCPT ); Mon, 14 Mar 2022 17:10:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235370AbiCNVKF (ORCPT ); Mon, 14 Mar 2022 17:10:05 -0400 Received: from mail-wm1-x32c.google.com (mail-wm1-x32c.google.com [IPv6:2a00:1450:4864:20::32c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A746E0F6 for ; Mon, 14 Mar 2022 14:08:53 -0700 (PDT) Received: by mail-wm1-x32c.google.com with SMTP id 19so10084119wmy.3 for ; Mon, 14 Mar 2022 14:08:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=algolia.com; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=onRiKUxqxTpyz6xmpPtyIH/p/E/1zKXRASWvdcQSPZI=; b=jq8Jv71y2M8KBXfZFfeFOrxZWXiIf59Pp9I2uiHQJKvhzLxrxoZFwarFgeJnMZFYZh G6woRIFKieK8tPoFzqMO6YXhAkO+me90TUA66ZC+dx2/lvKIN46Pke99ZM3zlRqiwnmn NHX40t8F09tKxPjijwuH58kNViOUHN99sQ2YU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=onRiKUxqxTpyz6xmpPtyIH/p/E/1zKXRASWvdcQSPZI=; b=q1+5LT4CdQwnqGyIzOb78aD86yrQ/q3edGoPGu7Xx7UNpOTpOlW4vZsOKSRcUqBdOl GsVebpMrc/bwa2SmAIyPQRelPJM35anLF1gMRY26BxJBRwu7CcgjlpLmy8i7jeTxxzrV S0z5qXJPoav3BBOdUwBQA+Ual39GW95yXl+/7Uo+beQrgJ9A033gZDMT7K6pQQhynncH oLzYU+iFbXgPuXpKcqjFNq3K2hnKCYmDa7+YCyLXIX4Q8j9kRASUJMCIX8Ku8Z3le7PS UU9KVmOLf4nCqRPKiOWCG9fOIl7/0KHfgYpuNoSdD5eDQrdsEvBpYqbbPEjLDPgDyD8i cGvw== X-Gm-Message-State: AOAM53252FVJMjT2ECpVOf9RJKcz+lWFCS6I3B6ZBZLda9b6v6ykpXA7 +AN3oLvV2Ahx1qevafLYaJEEow== X-Google-Smtp-Source: ABdhPJzX8jTnDaYoB4AC5+83XFsomeyAdGycJjrabKIOrVkyLQQ7Ss2sr43LQ+PTLiaN4bOSN0WEuw== X-Received: by 2002:a05:600c:4284:b0:389:c472:e05e with SMTP id v4-20020a05600c428400b00389c472e05emr772472wmc.19.1647292131761; Mon, 14 Mar 2022 14:08:51 -0700 (PDT) Received: from xavier-xps ([2a01:e0a:830:d971:cc11:3255:8bf2:4a49]) by smtp.gmail.com with ESMTPSA id n16-20020a5d4850000000b0020373b34961sm13883058wrs.66.2022.03.14.14.08.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Mar 2022 14:08:51 -0700 (PDT) Date: Mon, 14 Mar 2022 22:08:49 +0100 From: Xavier Roche To: Hugh Dickins Cc: Linus Torvalds , Linux Kernel Mailing List , Andrew Morton , Jean Delvare , Linux-MM Subject: Re: [PATCH v3] tmpfs: support for file creation time Message-ID: <20220314210849.GA121935@xavier-xps> References: <20220211213628.GA1919658@xavier-xps> <20220211213628.GA1919658@xavier-xps> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 02, 2022 at 12:17:30PM -0800, Hugh Dickins wrote: > Please ignore this patch for now: I presume Xavier did not understand > the "from akpm to Linus in next merge window" flow, and thought he had > to resend the patch to you. I will resend a fixed v4 version in a moment, sorry for the noise (and I indeed did not fully understand the flow). > > And finally - if we really want to treat btime as a first-class entity > > and expect things like tmpfs to support it, then we should just bite > > the bullet and put it in 'struct inode' along with the other times. > I've no objection if someone does that later. I might give it a try if this is something that can be of interest. The idea of having btime in 'struct inode' would make the btime a first-class citizen, allowing to have more consistent (w.r.t filesystem types) behavior. This would also mean allowing to _change_ it, typically to allow archivers to set the creation time as they do for {a,c,m}time. Currently, birth time semantic is bound to the current filesystem's life cycle and as such is irrelevant after a restore, or a 'tar xf'. The only gray area to me is whether or not we "can" always change this property without unforeseen consequences, typically for ext4.