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=-4.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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 CCF59C433E1 for ; Mon, 24 Aug 2020 11:40:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7CB720774 for ; Mon, 24 Aug 2020 11:40:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="haPUNuAJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727846AbgHXLkH (ORCPT ); Mon, 24 Aug 2020 07:40:07 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:44690 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727779AbgHXLj7 (ORCPT ); Mon, 24 Aug 2020 07:39:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598269198; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=MGX6w16Fo/bNfsQoLln4y8H1qAVBrOEnXuwzrhqCE4c=; b=haPUNuAJVdxo2GJ9CWM/q/r5A20D4vE9UsSwjZBE3q5oEc8XxdAgCVjJEfl4vGPK4oJ3t4 P/CxPoWq5jjsjKJpRSS4uqwXPaMbYy4W7p7+/guiS89ntu3JjfzdMXzwUZlrpRjWs9X0Af zO5t3hzZH20dRfV9+bis/VFVehUV3vM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-482-kXz9_3IgNIKXnoB8N7DUXA-1; Mon, 24 Aug 2020 07:39:54 -0400 X-MC-Unique: kXz9_3IgNIKXnoB8N7DUXA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CEAA618B9F10; Mon, 24 Aug 2020 11:39:53 +0000 (UTC) Received: from localhost (ovpn-114-217.ams2.redhat.com [10.36.114.217]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1D6AE2B3A1; Mon, 24 Aug 2020 11:39:52 +0000 (UTC) From: Giuseppe Scrivano To: Amir Goldstein Cc: Miklos Szeredi , Vivek Goyal , overlayfs , Daniel J Walsh , Steven Whitehouse Subject: Re: [PATCH v5] overlayfs: Provide a mount option "volatile" to skip sync References: <20200722175024.GA608248@redhat.com> <87h7svyqsd.fsf@redhat.com> Date: Mon, 24 Aug 2020 13:39:50 +0200 In-Reply-To: (Amir Goldstein's message of "Mon, 24 Aug 2020 13:59:41 +0300") Message-ID: <87a6yknugp.fsf@redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-unionfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org Hi Amir, Amir Goldstein writes: > On Mon, Aug 24, 2020 at 11:15 AM Miklos Szeredi wrote: >> >> On Sat, Aug 22, 2020 at 11:27 AM Giuseppe Scrivano wrote: >> > >> > Vivek Goyal writes: >> > >> > > Container folks are complaining that dnf/yum issues too many sync while >> > > installing packages and this slows down the image build. Build >> > > requirement is such that they don't care if a node goes down while >> > > build was still going on. In that case, they will simply throw away >> > > unfinished layer and start new build. So they don't care about syncing >> > > intermediate state to the disk and hence don't want to pay the price >> > > associated with sync. >> > > >> >> [...] >> >> > Ping. >> > >> > Is there anything holding this patch? >> >> Not sure what happened with protection against mounting a volatile >> overlay twice, I don't see that in the patch. > > Do you mean protection only for new kernels or old kernels as well? > > The latter can be achieved by using $workdir/volatile/ as upperdir > instead of $upperdir. > Or maybe even use $workdir/work/incompat/volatile/upper, so if older > kernel tries to re-use that $workdir, it will fail to mount rw with error: > > overlayfs: cleanup of 'incompat/volatile' failed (-39) > > If we agree to that, then upperdir= should not be provided at all when > specifying "volatile". in this case, what does a program need to do to remount the overlay more than once? Is it enough to just delete a file? Thanks, Giuseppe