From patchwork Thu Dec 12 16:38:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 11288907 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 07B7B138C for ; Thu, 12 Dec 2019 17:39:39 +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 D3ACF214AF for ; Thu, 12 Dec 2019 17:39:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HC5dDoIg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D3ACF214AF 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:34827 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifSR7-0001RN-Dk for patchwork-qemu-devel@patchwork.kernel.org; Thu, 12 Dec 2019 12:39:37 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:37628) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifRX5-0007rX-00 for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ifRX3-0004vV-SC for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:42 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:44889 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 1ifRX3-0004ul-NY for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:41:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576168901; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5OzLXiuaEm9rsBZclFzC9sSXge9QS5piPP1Nh1UzqHM=; b=HC5dDoIgcCnK7uh3H7S44uvOu0LmPl8eALryOnbLtbjeHQB6Tk0UDmzvzjukOYuBnOqNPE XuBTo7YB/MYVH0G0wXRzLiuNwN4dUko5YggWTSU2c5od8sWt/AI5zk2rrHP2ggJcm13blU hBlroFXICEYsvbXqUNrEaQAUIN2a9T8= 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-349-V48IxQcPMaKVsvTKlWEoBA-1; Thu, 12 Dec 2019 11:41:40 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4397D800D5A for ; Thu, 12 Dec 2019 16:41:39 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-116-226.ams2.redhat.com [10.36.116.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2BB9560BE1; Thu, 12 Dec 2019 16:41:35 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Subject: [PATCH 096/104] virtiofsd: Reset O_DIRECT flag during file open Date: Thu, 12 Dec 2019 16:38:56 +0000 Message-Id: <20191212163904.159893-97-dgilbert@redhat.com> In-Reply-To: <20191212163904.159893-1-dgilbert@redhat.com> References: <20191212163904.159893-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: V48IxQcPMaKVsvTKlWEoBA-1 X-Mimecast-Spam-Score: 0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: , Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Vivek Goyal If an application wants to do direct IO and opens a file with O_DIRECT in guest, that does not necessarily mean that we need to bypass page cache on host as well. So reset this flag on host. If somebody needs to bypass page cache on host as well (and it is safe to do so), we can add a knob in daemon later to control this behavior. I check virtio-9p and they do reset O_DIRECT flag. Signed-off-by: Vivek Goyal Reviewed-by: Daniel P. Berrangé --- tools/virtiofsd/passthrough_ll.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index cf6b548eee..6b3d396b6f 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -1705,6 +1705,13 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name, goto out; } + /* + * O_DIRECT in guest should not necessarily mean bypassing page + * cache on host as well. If somebody needs that behavior, it + * probably should be a configuration knob in daemon. + */ + fi->flags &= ~O_DIRECT; + fd = openat(parent_inode->fd, name, (fi->flags | O_CREAT) & ~O_NOFOLLOW, mode); err = fd == -1 ? errno : 0; @@ -1934,6 +1941,13 @@ static void lo_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) fi->flags &= ~O_APPEND; } + /* + * O_DIRECT in guest should not necessarily mean bypassing page + * cache on host as well. If somebody needs that behavior, it + * probably should be a configuration knob in daemon. + */ + fi->flags &= ~O_DIRECT; + sprintf(buf, "%i", lo_fd(req, ino)); fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW); if (fd == -1) {