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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 A535BECE587 for ; Tue, 1 Oct 2019 16:49:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 728D220659 for ; Tue, 1 Oct 2019 16:49:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569948549; bh=2i8+d2TT3yX8/1+HhuIWKqY7fbcAmg4UD+/uh4pIKuY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MMYf7jF443W7KSSLeNesjrr3tP/C4JBs8kmHauPeTLcBJhumD7zAL4vpzZiAeoB+n XdAU4NE77fhsq5HYXQUHitcUulG0yRvmMIA5Z+C8TXJffaPgQSmYiUEJwuKDIwwzJm iYCMLSVGBcl7gbH2Tu+yv5ArKd104Z2F4SDbIM4c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388891AbfJAQtI (ORCPT ); Tue, 1 Oct 2019 12:49:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:57594 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390184AbfJAQpK (ORCPT ); Tue, 1 Oct 2019 12:45:10 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7F4C72190F; Tue, 1 Oct 2019 16:45:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569948309; bh=2i8+d2TT3yX8/1+HhuIWKqY7fbcAmg4UD+/uh4pIKuY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q2cst86dE3KW9QpoKzrlIpGI68YGySdgr/IMAIK2T6y/Bgwxb4uSMDibRMvfjtPag 4TbQszZIRW+1JfLTV9BHQbxTAtj2IE5vNrLBXR1qYZlojX/Lk+93l5yaovl9ibuHVW AhBUBC7qcH5P8nFmwqA51qqxlKp9ZRJNEA17GsZw= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Chengguang Xu , Dominique Martinet , Sasha Levin , v9fs-developer@lists.sourceforge.net Subject: [PATCH AUTOSEL 4.9 03/19] 9p: avoid attaching writeback_fid on mmap with type PRIVATE Date: Tue, 1 Oct 2019 12:44:49 -0400 Message-Id: <20191001164505.16708-3-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191001164505.16708-1-sashal@kernel.org> References: <20191001164505.16708-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chengguang Xu [ Upstream commit c87a37ebd40b889178664c2c09cc187334146292 ] Currently on mmap cache policy, we always attach writeback_fid whether mmap type is SHARED or PRIVATE. However, in the use case of kata-container which combines 9p(Guest OS) with overlayfs(Host OS), this behavior will trigger overlayfs' copy-up when excute command inside container. Link: http://lkml.kernel.org/r/20190820100325.10313-1-cgxu519@zoho.com.cn Signed-off-by: Chengguang Xu Signed-off-by: Dominique Martinet Signed-off-by: Sasha Levin --- fs/9p/vfs_file.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c index 79ff727254bb6..e963b83afc717 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -528,6 +528,7 @@ v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma) v9inode = V9FS_I(inode); mutex_lock(&v9inode->v_mutex); if (!v9inode->writeback_fid && + (vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE)) { /* * clone a fid and add it to writeback_fid @@ -629,6 +630,8 @@ static void v9fs_mmap_vm_close(struct vm_area_struct *vma) (vma->vm_end - vma->vm_start - 1), }; + if (!(vma->vm_flags & VM_SHARED)) + return; p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma); -- 2.20.1