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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 D4A6EC19759 for ; Thu, 1 Aug 2019 14:22:03 +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 A29582087E for ; Thu, 1 Aug 2019 14:22:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A29582087E 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]:56312 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1htBxy-000107-U8 for qemu-devel@archiver.kernel.org; Thu, 01 Aug 2019 10:22:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53256) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1htBwW-0000Aq-UX for qemu-devel@nongnu.org; Thu, 01 Aug 2019 10:20:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1htBwS-0007N4-IT for qemu-devel@nongnu.org; Thu, 01 Aug 2019 10:20:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58248) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1htBwP-0007I5-2u for qemu-devel@nongnu.org; Thu, 01 Aug 2019 10:20:26 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A0BE6E8CAA; Thu, 1 Aug 2019 14:20:22 +0000 (UTC) Received: from work-vm (ovpn-117-184.ams2.redhat.com [10.36.117.184]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 274CC5D9E1; Thu, 1 Aug 2019 14:20:18 +0000 (UTC) Date: Thu, 1 Aug 2019 15:20:16 +0100 From: "Dr. David Alan Gilbert" To: Eric Blake Message-ID: <20190801142016.GI2773@work-vm> References: <5D3F8F04.3030404@huawei.com> <4ec43f2f-1d72-5fe1-3b93-2c75ee6f87b4@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4ec43f2f-1d72-5fe1-3b93-2c75ee6f87b4@redhat.com> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Thu, 01 Aug 2019 14:20:22 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [Virtio-fs] [PATCH] virtiofsd: fix compile error if 'F_OFD_GETLK' not defined 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: piaojun , virtio-fs@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Eric Blake (eblake@redhat.com) wrote: > On 7/29/19 7:27 PM, piaojun wrote: > > Use F_GETLK for fcntl when F_OFD_GETLK not defined. > > Which system are you hitting this problem on? > > The problem with F_GETLK is that it is NOT as safe as F_OFD_GETLK. > > We already have fcntl_op_getlk and qemu_probe_lock_ops() in util/osdep.c > to not only determine which form to use, but also to emit a warning to > the end user if we had to fall back to the unsafe F_GETLK. Why is your > code not reusing that logic? > > > > > Signed-off-by: Jun Piao > > --- > > contrib/virtiofsd/passthrough_ll.c | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > > diff --git a/contrib/virtiofsd/passthrough_ll.c b/contrib/virtiofsd/passthrough_ll.c > > index 9ae1381..757785b 100644 > > --- a/contrib/virtiofsd/passthrough_ll.c > > +++ b/contrib/virtiofsd/passthrough_ll.c > > @@ -1619,7 +1619,11 @@ static void lo_getlk(fuse_req_t req, fuse_ino_t ino, > > return; > > } > > > > +#ifdef F_OFD_GETLK > > ret = fcntl(plock->fd, F_OFD_GETLK, lock); > > +#else > > + ret = fcntl(plock->fd, F_GETLK, lock); > > +#endif > > Hmm. Since this is in contrib, you are trying to compile something that > is independent of util/osdep.c (at least, I assume that's the case, as > contrib/virtiofsd/ is not even part of qemu.git master yet - in which > case, why is this not being squashed in to the patch introducing that > file, rather than sent standalone). On the other hand, that raises the > question - who is trying to use virtiofsd on a kernel that is too old to > provid F_OFD_GETLK? Isn't the whole point of virtiofsd to be speeding > up modern usage, at which point an old kernel is just gumming up the > works? It seems like you are better off letting compilation fail on a > system that is too old to support decent F_OFD_GETLK, rather than > silently falling back to something that is unsafe. It is, but I guess the answer here is someone wanted to build on RHEL7. Dave > > -- > Eric Blake, Principal Software Engineer > Red Hat, Inc. +1-919-301-3226 > Virtualization: qemu.org | libvirt.org > > _______________________________________________ > Virtio-fs mailing list > Virtio-fs@redhat.com > https://www.redhat.com/mailman/listinfo/virtio-fs -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK