From patchwork Fri Jun 28 18:34:51 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: 11023271 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 011AA138D for ; Fri, 28 Jun 2019 18:36:43 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C73C628174 for ; Fri, 28 Jun 2019 18:36:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BACEC2834A; Fri, 28 Jun 2019 18:36:42 +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 61EDB28174 for ; Fri, 28 Jun 2019 18:36:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727106AbfF1SgZ (ORCPT ); Fri, 28 Jun 2019 14:36:25 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:57350 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727100AbfF1SgY (ORCPT ); Fri, 28 Jun 2019 14:36:24 -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 x5SIYQRG108883; Fri, 28 Jun 2019 18:34:57 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=hDvAuKrMfSUW7AbzqNfZSt/8R1aeCpTe5TGF8T8lRYc=; b=jRRaM6/cr2s1fN3nJa8yFGdPIm650NetSXoqzer/0L2yCpma7vUORBQ7mNoB6zegt3yV 2WaPx92M+xx36rc1eyqskvJFn7teZ2EjeHlgbNGpAU6lHKWmerm/E2KLpNPo+wGArDa1 K8c2RTjP5b+vZvA0NI05COGDHcOesafa6zvfR7n2l6a4vNBTxFEAFBe9kju/lSpjuOFA sfZS2IZRGf2rVNN8QJ4XjaPhFu7Dg9WBD5nM9iuWr+1Q8xXsS4BvM2zQ5vYY9tZSIFZD S1ts7ni4Y8CuHWQnPN6AP834iFHazwJqlHUIP93kvyf0vy/iHyKGjVX9sQiIRpp9eMnJ xw== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2130.oracle.com with ESMTP id 2t9brtq3hf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 28 Jun 2019 18:34:57 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5SIXXPt000897; Fri, 28 Jun 2019 18:34:56 GMT Received: from pps.reinject (localhost [127.0.0.1]) by userp3020.oracle.com with ESMTP id 2tat7e3gab-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 28 Jun 2019 18:34:56 +0000 Received: from userp3020.oracle.com (userp3020.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.27/8.16.0.27) with SMTP id x5SIYuM8003117; Fri, 28 Jun 2019 18:34:56 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3020.oracle.com with ESMTP id 2tat7e3ga7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 28 Jun 2019 18:34:56 +0000 Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x5SIYsCq029052; Fri, 28 Jun 2019 18:34:54 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 28 Jun 2019 11:34:54 -0700 Subject: [PATCH 2/4] 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: Fri, 28 Jun 2019 11:34:51 -0700 Message-ID: <156174689192.1557469.17945809794748607270.stgit@magnolia> In-Reply-To: <156174687561.1557469.7505651950825460767.stgit@magnolia> References: <156174687561.1557469.7505651950825460767.stgit@magnolia> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9302 signatures=668688 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=753 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906280210 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 91482ab4556a..0efe749de577 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3567,4 +3567,15 @@ static inline void simple_fill_fsxattr(struct fsxattr *fa, __u32 xflags) fa->fsx_xflags = xflags; } +/* + * 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 */