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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 36E40ECE599 for ; Wed, 16 Oct 2019 22:23:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 039B221848 for ; Wed, 16 Oct 2019 22:23:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571264619; bh=AAKQlzbvTxzLTVQbz11o7zrn12sb1NA0ge1J0S9RcAM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mGfoXi08k1dZMTz/NNYwxxCcHrLYQFOM73S5qE6VkOEdUctBWDzKbsV3tJY+srUMP 2GVF256w/xtV+VrTqIazDAbk/rsCTCW0PvhD0LyTJ92G91y8GZa9EH/P0Uz8pAZMcG Oxk8cDYepxu3bdUjcBs8vbtC0G/FXDbUWNnrPmkI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437022AbfJPVwz (ORCPT ); Wed, 16 Oct 2019 17:52:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:41328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2436940AbfJPVwy (ORCPT ); Wed, 16 Oct 2019 17:52:54 -0400 Received: from localhost (unknown [192.55.54.58]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8F82921925; Wed, 16 Oct 2019 21:52:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571262773; bh=AAKQlzbvTxzLTVQbz11o7zrn12sb1NA0ge1J0S9RcAM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TJbVpTpucQW8CcoeeZLH07f8AbjVlheCvQNdxDpZOMDczdDbATDtyCfR25UBw1I/x 72NQKUo4cg+vn0AXOc91X6Hh7bNhKarZBExwTZUBwVbjCrW/w/WAJ0WNevpnVZhvZm JHs+OQ61P1Uye24Z9bpyAMqn5tf2/X6712bM7Zjc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chengguang Xu , Dominique Martinet , Sasha Levin Subject: [PATCH 4.4 14/79] 9p: avoid attaching writeback_fid on mmap with type PRIVATE Date: Wed, 16 Oct 2019 14:49:49 -0700 Message-Id: <20191016214743.174898914@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016214729.758892904@linuxfoundation.org> References: <20191016214729.758892904@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 373cc50544e91..9dbf371471261 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