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=-7.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 10057C433E1 for ; Mon, 22 Jun 2020 17:51:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E605B20707 for ; Mon, 22 Jun 2020 17:51:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592848266; bh=G3HuBpldr6eXEWho8mbo/GZIcQlxl/xiYVdS1AgPYlQ=; h=Subject:To:Cc:From:Date:List-ID:From; b=R7z7jeyf2nT8IIeUbTzj9Ib7raB7lwjp+UY3bcLNfUcY2dq/MDSny98Hu1xh1kaHc Q/WZRVTpIWeEPCr2ROGRGPiS9mckk+e9nPLAHK0l2QSDMBROEF6wtP/4fiZY5FiXkD szyrIB9MasyUcJsDo1wk23ur/Kxre+neAb7gXMuY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730118AbgFVRvG (ORCPT ); Mon, 22 Jun 2020 13:51:06 -0400 Received: from wforward5-smtp.messagingengine.com ([64.147.123.35]:55517 "EHLO wforward5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730099AbgFVRvG (ORCPT ); Mon, 22 Jun 2020 13:51:06 -0400 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailforward.west.internal (Postfix) with ESMTP id 8405A11FC; Mon, 22 Jun 2020 13:51:05 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute1.internal (MEProxy); Mon, 22 Jun 2020 13:51:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=S0tm8c tq2kdWIk0zY5WaDylbtPYxgoADz+yDthd9nD0=; b=gqryWox22tbJyVK/R2cN1u YekvrwTI5pzQy/sdauRig77y0wADvSB4v70fKufvFPitOrr4tlTWt1U8FUrgspYw jjDBfKR/4Vg89p5h6EZfXU6IV3k0Akj4Rt0V7lG3A/nKEsXIrZr4vOntq1tXLotG 1KS5Snec0KYkR1HQ/jHx9GjfkvMTzmQrwzjCaaek/+im52MfSqFOJNN735BxoT/B RlrFSU3is2JeHQobU6cdOOwNSqEI616qQHEDaW6k1xBZaX5IlZ0TPG49XtUWb4aM jyCBlwbtbkf8GLXEPEDfkufbT9cl793VoEW28g94rS50DwoyNLGzOOInMAjH/SEQ == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduhedrudekvddguddulecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecunecujfgurhepuffvhfffkfggtgfgsehtkeertd dttdflnecuhfhrohhmpeeoghhrvghgkhhhsehlihhnuhigfhhouhhnuggrthhiohhnrdho rhhgqeenucggtffrrghtthgvrhhnpeeiteevheeuvdfhtdfgvdeiieehheefleevveehje duteevueevledujeejgfetheenucfkphepkeefrdekiedrkeelrddutdejnecuvehluhhs thgvrhfuihiivgepfeenucfrrghrrghmpehmrghilhhfrhhomhepghhrvghgsehkrhhorg hhrdgtohhm X-ME-Proxy: Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) by mail.messagingengine.com (Postfix) with ESMTPA id BEFD030673B7; Mon, 22 Jun 2020 13:51:04 -0400 (EDT) Subject: FAILED: patch "[PATCH] ext4: avoid race conditions when remounting with options that" failed to apply to 4.19-stable tree To: tytso@mit.edu Cc: From: Date: Mon, 22 Jun 2020 19:50:57 +0200 Message-ID: <159284825795161@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 829b37b8cddb1db75c1b7905505b90e593b15db1 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 10 Jun 2020 11:16:37 -0400 Subject: [PATCH] ext4: avoid race conditions when remounting with options that change dax Trying to change dax mount options when remounting could allow mount options to be enabled for a small amount of time, and then the mount option change would be reverted. In the case of "mount -o remount,dax", this can cause a race where files would temporarily treated as DAX --- and then not. Cc: stable@kernel.org Reported-by: syzbot+bca9799bf129256190da@syzkaller.appspotmail.com Signed-off-by: Theodore Ts'o diff --git a/fs/ext4/super.c b/fs/ext4/super.c index a22d67c5bc00..edf06c1bee9d 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2104,16 +2104,40 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token, switch (token) { case Opt_dax: case Opt_dax_always: + if (is_remount && + (!(sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) || + (sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_NEVER))) { + fail_dax_change_remount: + ext4_msg(sb, KERN_ERR, "can't change " + "dax mount option while remounting"); + return -1; + } + if (is_remount && + (test_opt(sb, DATA_FLAGS) == + EXT4_MOUNT_JOURNAL_DATA)) { + ext4_msg(sb, KERN_ERR, "can't mount with " + "both data=journal and dax"); + return -1; + } ext4_msg(sb, KERN_WARNING, "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); sbi->s_mount_opt |= EXT4_MOUNT_DAX_ALWAYS; sbi->s_mount_opt2 &= ~EXT4_MOUNT2_DAX_NEVER; break; case Opt_dax_never: + if (is_remount && + (!(sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_NEVER) || + (sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS))) + goto fail_dax_change_remount; sbi->s_mount_opt2 |= EXT4_MOUNT2_DAX_NEVER; sbi->s_mount_opt &= ~EXT4_MOUNT_DAX_ALWAYS; break; case Opt_dax_inode: + if (is_remount && + ((sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) || + (sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_NEVER) || + !(sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_INODE))) + goto fail_dax_change_remount; sbi->s_mount_opt &= ~EXT4_MOUNT_DAX_ALWAYS; sbi->s_mount_opt2 &= ~EXT4_MOUNT2_DAX_NEVER; /* Strictly for printing options */ @@ -5454,12 +5478,6 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) err = -EINVAL; goto restore_opts; } - if (test_opt(sb, DAX_ALWAYS)) { - ext4_msg(sb, KERN_ERR, "can't mount with " - "both data=journal and dax"); - err = -EINVAL; - goto restore_opts; - } } else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA) { if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) { ext4_msg(sb, KERN_ERR, "can't mount with " @@ -5475,18 +5493,6 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) goto restore_opts; } - if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT4_MOUNT_DAX_ALWAYS || - (sbi->s_mount_opt2 ^ old_opts.s_mount_opt2) & EXT4_MOUNT2_DAX_NEVER || - (sbi->s_mount_opt2 ^ old_opts.s_mount_opt2) & EXT4_MOUNT2_DAX_INODE) { - ext4_msg(sb, KERN_WARNING, "warning: refusing change of " - "dax mount option with busy inodes while remounting"); - sbi->s_mount_opt &= ~EXT4_MOUNT_DAX_ALWAYS; - sbi->s_mount_opt |= old_opts.s_mount_opt & EXT4_MOUNT_DAX_ALWAYS; - sbi->s_mount_opt2 &= ~(EXT4_MOUNT2_DAX_NEVER | EXT4_MOUNT2_DAX_INODE); - sbi->s_mount_opt2 |= old_opts.s_mount_opt2 & - (EXT4_MOUNT2_DAX_NEVER | EXT4_MOUNT2_DAX_INODE); - } - if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) ext4_abort(sb, EXT4_ERR_ESHUTDOWN, "Abort forced by user");