From patchwork Thu Jan 23 16:46:18 2020 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: 11349199 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 01AC3109A for ; Thu, 23 Jan 2020 20:11:36 +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 CB41C22522 for ; Thu, 23 Jan 2020 20:11:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="O2lR6yTk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB41C22522 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]:33125 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iuipD-0001Ju-1T for patchwork-qemu-devel@patchwork.kernel.org; Thu, 23 Jan 2020 15:11:35 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:42547) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iufev-00066Z-Kw for qemu-devel@nongnu.org; Thu, 23 Jan 2020 11:48:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iufeu-00005t-GV for qemu-devel@nongnu.org; Thu, 23 Jan 2020 11:48:45 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:29808 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 1iufeu-000058-DV for qemu-devel@nongnu.org; Thu, 23 Jan 2020 11:48:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579798124; 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=IY/4VhvWhbyo1+yBwmrgTORFYZ6C1n23UZLt2zXvGZI=; b=O2lR6yTkc447IFjgQrxD/DpS0oM1YQ7OFxQow/gpAp+x7W1JK4OM32zI+S2DNy/cQMK1P3 iVb1ZRcd6QOMHB1cCOMWZNVlL+nSjWYnIJ5ZxiiVL4vS7rWAlnXFI46MKZQv6oHc/wK7Xt 4Zld7jaufRPLGYjl7vtW1FrnpNM9tis= 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-440-WoVM-XwMNhWcLHSW55m0-A-1; Thu, 23 Jan 2020 11:48:42 -0500 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 E18E39278C for ; Thu, 23 Jan 2020 16:48:41 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-116-110.ams2.redhat.com [10.36.116.110]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3A09F19C69; Thu, 23 Jan 2020 16:48:41 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com Subject: [PULL 096/108] virtiofsd: Reset O_DIRECT flag during file open Date: Thu, 23 Jan 2020 16:46:18 +0000 Message-Id: <20200123164630.91498-97-dgilbert@redhat.com> In-Reply-To: <20200123164630.91498-1-dgilbert@redhat.com> References: <20200123164630.91498-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: WoVM-XwMNhWcLHSW55m0-A-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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: , 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 Signed-off-by: Dr. David Alan Gilbert --- 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 ccbbec18b0..948cb19c77 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -1721,6 +1721,13 @@ 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; @@ -1950,6 +1957,13 @@ 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) {