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=-6.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_PASS,UNPARSEABLE_RELAY 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 165ADC282DC for ; Wed, 17 Apr 2019 19:04:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6BBD2073F for ; Wed, 17 Apr 2019 19:04:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="PGpVhSwj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732921AbfDQTEb (ORCPT ); Wed, 17 Apr 2019 15:04:31 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:42338 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729291AbfDQTEb (ORCPT ); Wed, 17 Apr 2019 15:04:31 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3HIwqNW168716; Wed, 17 Apr 2019 19:04:29 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : from : to : cc : date : message-id : mime-version : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=tJjUPprNZ1wKy9741AhGUQYtsmORe3rs1XCk6inkF1g=; b=PGpVhSwjWwjZhLcFGeJMy4FSK4TQvpDW/+Z1BwxTqP4qSxpar+qyGMKVU0s/Iuk1GiR+ TtTnA+ISP2oXpuRIAOBIh8TMz5PJMzPlSkPJoP5HQg5w5RNZe0zw/dbx7Os2kfeSg9hx kWpXAEq9cK8EqGWGWsBAbUK7XaIIw7jPQpwW6m113y0Sh5ETiVTzeG7U65EvWIDjN9lR Wkcid6e5MSS4aO0d4pkB27GK+ZJKBASFvoBDhb1+VbS0gkPw/Tkl/KCRnIJxLpDf+EOs 2CQZpjruLCmLouY9yZleRDTM1z+6shFtB8OBsEXekX/n6LMVefoQ16lZSGp26/7H64ru BA== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2130.oracle.com with ESMTP id 2rvwk3w090-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Apr 2019 19:04:29 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3HJ34ca081874; Wed, 17 Apr 2019 19:04:28 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3030.oracle.com with ESMTP id 2ru4vtyxhp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Apr 2019 19:04:28 +0000 Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x3HJ4RDr008926; Wed, 17 Apr 2019 19:04:28 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 17 Apr 2019 12:04:27 -0700 Subject: [PATCH v2 0/8] vfs: make immutable files actually immutable From: "Darrick J. Wong" To: darrick.wong@oracle.com Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mm@kvack.org Date: Wed, 17 Apr 2019 12:04:26 -0700 Message-ID: <155552786671.20411.6442426840435740050.stgit@magnolia> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9230 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=842 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904170125 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9230 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=866 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904170125 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hi all, The chattr(1) manpage has this to say about the immutable bit that system administrators can set on files: "A file with the 'i' attribute cannot be modified: it cannot be deleted or renamed, no link can be created to this file, most of the file's metadata can not be modified, and the file can not be opened in write mode." Given the clause about how the file 'cannot be modified', it is surprising that programs holding writable file descriptors can continue to write to and truncate files after the immutable flag has been set, but they cannot call other things such as utimes, fallocate, unlink, link, setxattr, or reflink. Since the immutable flag is only settable by administrators, resolve this inconsistent behavior in favor of the documented behavior -- once the flag is set, the file cannot be modified, period. If you're going to start using this mess, you probably ought to just pull from my git trees, which are linked below. This is an extraordinary way to destroy everything. Enjoy! Comments and questions are, as always, welcome. --D kernel git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfs-linux.git/log/?h=immutable-files fstests git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=immutable-files