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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id F19F7C433F5 for ; Mon, 14 Mar 2022 21:08:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 508CD6B0071; Mon, 14 Mar 2022 17:08:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4923F8D0002; Mon, 14 Mar 2022 17:08:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 30BBB8D0001; Mon, 14 Mar 2022 17:08:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.26]) by kanga.kvack.org (Postfix) with ESMTP id 1C7F76B0071 for ; Mon, 14 Mar 2022 17:08:54 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id AE6C46201B for ; Mon, 14 Mar 2022 21:08:53 +0000 (UTC) X-FDA: 79244231346.09.8C59CBC Received: from mail-wm1-f47.google.com (mail-wm1-f47.google.com [209.85.128.47]) by imf15.hostedemail.com (Postfix) with ESMTP id 2740DA0007 for ; Mon, 14 Mar 2022 21:08:52 +0000 (UTC) Received: by mail-wm1-f47.google.com with SMTP id q7-20020a7bce87000000b00382255f4ca9so306453wmj.2 for ; Mon, 14 Mar 2022 14:08:52 -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=zzm4miiPpMObYppWCGPJbHYwEc7Tb1dVnQsstqvOFz9TpMpuCn9famhBXvv0ZAgELC h2otZAnnJy4bl923cM8euSu/sY05nkWzfDJJs/mvgxMDkMIkS0Xb79t9mzuGqX1PVUjN 6t23a9Mv2JY2J0MysKGrKmqX6yibvqmiBdGQ9Ik9E16AxNE1VXQpG/vIk83hyqbFa0la 2p+5iDYB9IM6lr0vyVrz8Fsn3hLgmVvxomLI7tUAX61u5sgnpUkFuxHyTWNLzIovn6Qz KMcMcusm9zfLoNuz7u9OPJ2AzayPNGB2zUgIkW43rqXrHg90BLGaQp5NstUOMdQfm8Cm Uusw== X-Gm-Message-State: AOAM530vApEszGfZX0lZ1jbU500HrFARSEwKjLaRbVYMLjCo26pbpe7O YH3T4S1navc1+9k0hLuIDAfRxg== 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: X-Rspam-User: Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=algolia.com header.s=google header.b=jq8Jv71y; dmarc=pass (policy=reject) header.from=algolia.com; spf=pass (imf15.hostedemail.com: domain of xavier.roche@algolia.com designates 209.85.128.47 as permitted sender) smtp.mailfrom=xavier.roche@algolia.com X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 2740DA0007 X-Stat-Signature: yok35q83n7mxe94o6y1ox5paacqy9iuq X-HE-Tag: 1647292132-819710 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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.