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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 0F271C35254 for ; Mon, 17 Feb 2020 12:23:54 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CE780206F4 for ; Mon, 17 Feb 2020 12:23:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="h+Np35pb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE780206F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44456 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j3fRJ-00059I-0k for qemu-devel@archiver.kernel.org; Mon, 17 Feb 2020 07:23:53 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:45866) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j3fQe-0004Nh-9C for qemu-devel@nongnu.org; Mon, 17 Feb 2020 07:23:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j3fQc-0001gk-8T for qemu-devel@nongnu.org; Mon, 17 Feb 2020 07:23:11 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:35263 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j3fQc-0001gR-4c for qemu-devel@nongnu.org; Mon, 17 Feb 2020 07:23:10 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581942189; 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=zCxfxYz61Wr0zuP9rf8O+0Xgv9ZAriImoz/HZaIK0co=; b=h+Np35pbf97PAwA13Jf7oXTD8plZMj8S+wxq49EGoZR//iFm4KZh38c6A4Zv91stEGGtCH 9QNPWvLKqdR52j4I98sRY9/CbvoozeRBz+lBWjC8M/R0J85tly1ljI//jbW5fBeanU2O8Y mVD9rakyTVNJYP6lckCj0EN/qFps3Hs= 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-188-Kt7CXcdrO3SvBl6eeG9klg-1; Mon, 17 Feb 2020 07:23:01 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CE471800D5F; Mon, 17 Feb 2020 12:22:59 +0000 (UTC) Received: from [10.3.116.180] (ovpn-116-180.phx2.redhat.com [10.3.116.180]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0113C8B551; Mon, 17 Feb 2020 12:22:58 +0000 (UTC) Subject: Re: [GEDI] [PATCH 07/17] gluster: Drop useless has_zero_init callback From: Eric Blake To: Niels de Vos References: <20200131174436.2961874-1-eblake@redhat.com> <20200131174436.2961874-8-eblake@redhat.com> <20200217080614.GG239686@ndevos-x270.lan.nixpanic.net> <457280bf-58da-404d-7ac1-edf1531623c9@redhat.com> Organization: Red Hat, Inc. Message-ID: Date: Mon, 17 Feb 2020 06:22:58 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <457280bf-58da-404d-7ac1-edf1531623c9@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: Kt7CXcdrO3SvBl6eeG9klg-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.61 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , "open list:GLUSTER" , qemu-block@nongnu.org, qemu-devel@nongnu.org, mreitz@redhat.com, david.edmondson@oracle.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2/17/20 6:03 AM, Eric Blake wrote: > > > > Creation or truncation should behave just as on a file on a local > > filesystem. So maybe qemu_gluster_known_zeroes is not needed at all? >=20 > Which version of gluster first required a regular filesystem backing for= =20 > all gluster files?=C2=A0 Does qemu support older versions (in which case,= =20 > what is the correct version-probing invocation to return 0 prior to that= =20 > point, and 1 after), or do all versions supported by qemu already=20 > guarantee zero initialization on creation or widening truncation by=20 > virtue of POSIX file semantics (in which case, patch 7 should instead=20 > switch to using .bdrv_has_zero_init_1 for both functions)?=C2=A0 Per=20 > configure, we probe for glusterfs_xlator_opt from gluster 4, which=20 > implies the code still tries to be portable to even older gluster, but=20 > I'm not sure if this squares with qemu-doc.texi which mentions our=20 > minimum distro policy (for example, now that qemu requires python 3=20 > consistent with our distro policy, that rules out several older systems= =20 > where older gluster was likely to be present). For reference, I quickly found commit efc6c070ac as an example of=20 bumping minimum versions (however, that commit is from 2018, so I'm sure=20 there are even more recent examples, just not with the same keywords=20 that I was searching for). --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org