From nobody Mon Feb 9 13:39:10 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1579789923; cv=none; d=zohomail.com; s=zohoarc; b=OO6lD+EaXZhUKm0mTjzH2BH5325EEmda/klwkn3zsnEA1JRXOsYmwpFyqMj4dLaMo6s5+ksfhE0rHZrgrkif1XC1N0DkKJjGXdsazhO4lwtbKtygXtuITDj+ItaNP59/Ajk2OdhQxxrll9OKHmSGkeFqjOusWmxaq983X29fhhw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1579789923; h=Content-Type:Content-Transfer-Encoding:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=IY/4VhvWhbyo1+yBwmrgTORFYZ6C1n23UZLt2zXvGZI=; b=L6MIkz6RyAaveheKNymS+JNcQ1tTzf+cVl7VUn+Z+Y2/M/vcYhJx5VIY5xp9WF1+jIBvfwvkACHd+epDsXlZ8kMxveFpZLORNxCsa2gkpU1eilqPNrYY3Ry9/4JDNF0Sw03o4ELdNhhUI7vfp6WVRQC45uzsSWH8LJhczWnM4mw= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1579789923650158.3909062211884; Thu, 23 Jan 2020 06:32:03 -0800 (PST) Received: from localhost ([::1]:58106 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iudWb-0001eG-QN for importer@patchew.org; Thu, 23 Jan 2020 09:32:01 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:41653) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iubAf-0004EF-PX for qemu-devel@nongnu.org; Thu, 23 Jan 2020 07:01:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iubAd-0006ZI-Qg for qemu-devel@nongnu.org; Thu, 23 Jan 2020 07:01:13 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:26534 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iubAd-0006YG-KL for qemu-devel@nongnu.org; Thu, 23 Jan 2020 07:01:11 -0500 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-151-Tpviu6rNMniR1fIwfZN9Jg-1; Thu, 23 Jan 2020 07:01:08 -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 997628010E4 for ; Thu, 23 Jan 2020 12:01:07 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.36.118.0]) by smtp.corp.redhat.com (Postfix) with ESMTP id E18421CB; Thu, 23 Jan 2020 12:01:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579780870; 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=ePX95oZrOKYkifnyr/aUPS2GjL6gxlcXPC24+T8sWI9QkuDB9JZsfVFHML5eqNLn97DK1R qqbvoBckLPrqnQgVBuyB3ZeEn4FQbJfafrr5QZqCeecstiuqji525a/hU5t/aGfPaQeTcu 5Qikth5ZsJi2EL98HKlzbWOQzl9dOOk= From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com Subject: [PULL 099/111] virtiofsd: Reset O_DIRECT flag during file open Date: Thu, 23 Jan 2020 11:58:29 +0000 Message-Id: <20200123115841.138849-100-dgilbert@redhat.com> In-Reply-To: <20200123115841.138849-1-dgilbert@redhat.com> References: <20200123115841.138849-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: Tpviu6rNMniR1fIwfZN9Jg-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 207.211.31.120 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" 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. Berrang=C3=A9 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 par= ent, const char *name, goto out; } =20 + /* + * 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 &=3D ~O_DIRECT; + fd =3D openat(parent_inode->fd, name, (fi->flags | O_CREAT) & ~O_NOFOL= LOW, mode); err =3D fd =3D=3D -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 &=3D ~O_APPEND; } =20 + /* + * 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 &=3D ~O_DIRECT; + sprintf(buf, "%i", lo_fd(req, ino)); fd =3D openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW); if (fd =3D=3D -1) { --=20 2.24.1