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[209.132.180.67]) by mx.google.com with ESMTP id pv13si2740220ejb.79.2019.10.10.01.59.33; Thu, 10 Oct 2019 01:59:56 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=2K8V9sRd; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388702AbfJJIqi (ORCPT + 99 others); Thu, 10 Oct 2019 04:46:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:52372 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389340AbfJJIqd (ORCPT ); Thu, 10 Oct 2019 04:46:33 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 9EAE4208C3; Thu, 10 Oct 2019 08:46:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570697193; bh=ygCTvRpC/E8gPrphJSMIGoYq+fQYGL1AUKhHOHVrbMM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2K8V9sRdfVRb0VRfILRERj6vQgR2HFgDYm7NmNlSJNsQkcgeAhwX6R42b3i1+aRDM HUWJJd8mJRbLveucd0jGU97KaGRUoul5pCcFeKVVp3SuA99hL4TpZnWZfa3vE7Vtfg BDlkX+FXU3yqrqCa0nYMbW8Zef0YIkCPVYSmvc2Y= 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 4.19 053/114] 9p: avoid attaching writeback_fid on mmap with type PRIVATE Date: Thu, 10 Oct 2019 10:36:00 +0200 Message-Id: <20191010083608.391759172@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191010083544.711104709@linuxfoundation.org> References: <20191010083544.711104709@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 05454a7e22dc2..550d0b169d7c2 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