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 0CAA5C43334 for ; Wed, 20 Jul 2022 16:29:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231215AbiGTQ3f (ORCPT ); Wed, 20 Jul 2022 12:29:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59414 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229581AbiGTQ3e (ORCPT ); Wed, 20 Jul 2022 12:29:34 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7D6F4186F8 for ; Wed, 20 Jul 2022 09:29:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658334572; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ucQ5TaXTrdPuaudEuwd2XaNeFmVaJveBPL1sbMmyZv8=; b=jSAc2gfKe4gfyxAGYGpCuknJqYuXScn/FlPKq4VrJBSamSf1aIgt/vFhVH47zSlb3zW2rv rULIL/Qy95NPUXMsBc+4lQ8twglRcr5XavcuWW22+t0jusYdyAsSDBSnVX5M5H3fsYVH5v gnNCBOCDwSxfDwL89TZ8g/IdEz9hq58= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-474-nTPgxi46P460zz5tdxR5iw-1; Wed, 20 Jul 2022 12:29:15 -0400 X-MC-Unique: nTPgxi46P460zz5tdxR5iw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 50FF0801755; Wed, 20 Jul 2022 16:29:15 +0000 (UTC) Received: from [172.16.176.1] (unknown [10.22.48.8]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 087C61121315; Wed, 20 Jul 2022 16:29:13 +0000 (UTC) From: "Benjamin Coddington" To: "Jeff Layton" Cc: "Lukas Czerner" , tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-fsdevel Subject: Re: should we make "-o iversion" the default on ext4 ? Date: Wed, 20 Jul 2022 12:29:12 -0400 Message-ID: <7F6417C7-1261-4C98-96B1-CB15744C04C1@redhat.com> In-Reply-To: References: <69ac1d3ef0f63b309204a570ef4922d2684ed7f9.camel@kernel.org> <20220720141546.46l2d7bxwukjhtl7@fedora> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On 20 Jul 2022, at 12:15, Jeff Layton wrote: > On Wed, 2022-07-20 at 11:56 -0400, Benjamin Coddington wrote: >> On 20 Jul 2022, at 10:38, Jeff Layton wrote: >>> On Wed, 2022-07-20 at 16:15 +0200, Lukas Czerner wrote: >>>> >>>> Is there a different way I am not seeing? >>>> >>> >>> Right, implementing this is the difficult bit actually since this uses a >>> MS_* flag. If we do make this the default, we'd definitely want to >>> continue allowing "-o noiversion" to disable it. >>> >>> Could we just reverse the default in libmount? It might cause this to >>> suddenly be enabled in some deployments, but in most cases, people >>> wouldn't even notice and they could still specify -o noiversion to turn >>> it off. >>> >>> Another idea would be to introduce new mount options for this, but >>> that's kind of nasty from a UI standpoint. >> >> Is it safe to set SB_I_VERSION at export time? If so, export_operations >> could grow an ->enable_iversion(). >> > > That sounds like it might be problematic. > > Consider the case where a NFSv4 client has cached file data and the > change attribute for the file. Server then reboots, but before the > export happens a local user makes a change to the file and it doesn't > update the i_version. Nfsd currently uses both ctime and i_version if its available, I'd expect that eliminates this case.