From patchwork Wed Jun 26 02:33:08 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 11016875 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6970714BB for ; Wed, 26 Jun 2019 02:34:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 59985285D4 for ; Wed, 26 Jun 2019 02:34:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4D854285E1; Wed, 26 Jun 2019 02:34:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E7F3E285D4 for ; Wed, 26 Jun 2019 02:34:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726865AbfFZCeq (ORCPT ); Tue, 25 Jun 2019 22:34:46 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:54008 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726441AbfFZCep (ORCPT ); Tue, 25 Jun 2019 22:34:45 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5Q2TGdr026619; Wed, 26 Jun 2019 02:33:14 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : from : to : cc : date : message-id : in-reply-to : references : mime-version : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=6o4YpGypPLzjpZ+ZkqPbxHMhFQ/fAokL7gT/kdrS3rU=; b=P4AM2r4O8nU7c0TP/3hgIM76kuCtB1+zo+JXjO4gCVkCBD/nNSLKwF4llit6BOzR/hos kVaWFauOSx3tSBZ1Kfb6P8sGvXDU1tR4q+dRkLjBcvlxDoQKuW0MY8FQgfsiNWesMYbB 5DJY7OmafEjZr2+80d2LAaWYW0pablNO6XKlpNbkUaUh8WlCsd9N/VfCLktuqrcMlFTW TtZhGmSg7llHlD3X8jtnVZsfOw+KwiDhbGpoAqw8vbFJ+cYyOu68k7d3v5OVSQqBKdRy XGnhdj8YiQjBBP6DTCVfRzJ+Uo7uR4+2Zz+kccWNVWHDl6kE2dSLvbJXB+hR4M3omUGE wQ== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by aserp2120.oracle.com with ESMTP id 2t9c9pqjkg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Jun 2019 02:33:14 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5Q2WjnS020557; Wed, 26 Jun 2019 02:33:13 GMT Received: from pps.reinject (localhost [127.0.0.1]) by aserp3020.oracle.com with ESMTP id 2t9p6uh2f7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 26 Jun 2019 02:33:13 +0000 Received: from aserp3020.oracle.com (aserp3020.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.27/8.16.0.27) with SMTP id x5Q2XD75021253; Wed, 26 Jun 2019 02:33:13 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3020.oracle.com with ESMTP id 2t9p6uh2f1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Jun 2019 02:33:13 +0000 Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x5Q2XBEe024251; Wed, 26 Jun 2019 02:33:11 GMT Received: from localhost (/10.159.230.235) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 25 Jun 2019 19:33:10 -0700 Subject: [PATCH 2/5] vfs: flush and wait for io when setting the immutable flag via SETFLAGS From: "Darrick J. Wong" To: matthew.garrett@nebula.com, yuchao0@huawei.com, tytso@mit.edu, darrick.wong@oracle.com, ard.biesheuvel@linaro.org, josef@toxicpanda.com, hch@infradead.org, clm@fb.com, adilger.kernel@dilger.ca, viro@zeniv.linux.org.uk, jack@suse.com, dsterba@suse.com, jaegeuk@kernel.org, jk@ozlabs.org Cc: reiserfs-devel@vger.kernel.org, linux-efi@vger.kernel.org, devel@lists.orangefs.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-nilfs@vger.kernel.org, linux-mtd@lists.infradead.org, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org Date: Tue, 25 Jun 2019 19:33:08 -0700 Message-ID: <156151638826.2283603.17232416684567376466.stgit@magnolia> In-Reply-To: <156151637248.2283603.8458727861336380714.stgit@magnolia> References: <156151637248.2283603.8458727861336380714.stgit@magnolia> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9299 signatures=668687 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=777 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906260027 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Darrick J. Wong When we're using FS_IOC_SETFLAGS to set the immutable flag on a file, we need to ensure that userspace can't continue to write the file after the file becomes immutable. To make that happen, we have to flush all the dirty pagecache pages to disk to ensure that we can fail a page fault on a mmap'd region, wait for pending directio to complete, and hope the caller locked out any new writes by holding the inode lock. Signed-off-by: Darrick J. Wong --- fs/inode.c | 21 +++++++++++++++++++-- include/linux/fs.h | 11 +++++++++++ 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index f08711b34341..65a412af3ffb 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -2193,7 +2193,8 @@ EXPORT_SYMBOL(current_time); /* * Generic function to check FS_IOC_SETFLAGS values and reject any invalid - * configurations. + * configurations. Once we're done, prepare the inode for whatever changes + * are coming down the pipeline. * * Note: the caller should be holding i_mutex, or else be sure that they have * exclusive access to the inode structure. @@ -2201,6 +2202,8 @@ EXPORT_SYMBOL(current_time); int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags, unsigned int flags) { + int ret; + /* * The IMMUTABLE and APPEND_ONLY flags can only be changed by * the relevant capability. @@ -2211,7 +2214,21 @@ int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags, !capable(CAP_LINUX_IMMUTABLE)) return -EPERM; - return 0; + /* + * Now that we're done checking the new flags, flush all pending IO and + * dirty mappings before setting S_IMMUTABLE on an inode via + * FS_IOC_SETFLAGS. If the flush fails we'll clear the flag before + * returning error. + */ + if (!S_ISREG(inode->i_mode) || IS_IMMUTABLE(inode) || + !(flags & FS_IMMUTABLE_FL)) + return 0; + + inode_set_flags(inode, S_IMMUTABLE, S_IMMUTABLE); + ret = inode_drain_writes(inode); + if (ret) + inode_set_flags(inode, 0, S_IMMUTABLE); + return ret; } EXPORT_SYMBOL(vfs_ioc_setflags_prepare); diff --git a/include/linux/fs.h b/include/linux/fs.h index 48322bfd7299..51266c9dbadc 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3561,4 +3561,15 @@ int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags, int vfs_ioc_fssetxattr_check(struct inode *inode, const struct fsxattr *old_fa, struct fsxattr *fa); +/* + * Flush file data before changing attributes. Caller must hold any locks + * required to prevent further writes to this file until we're done setting + * flags. + */ +static inline int inode_drain_writes(struct inode *inode) +{ + inode_dio_wait(inode); + return filemap_write_and_wait(inode->i_mapping); +} + #endif /* _LINUX_FS_H */