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 67E08C433DF for ; Mon, 22 Jun 2020 17:51:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BDCB20707 for ; Mon, 22 Jun 2020 17:51:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592848265; bh=TQce5tQ0bWqATldEBjByAwnOQ71wdKfMXR1eu0DAK4w=; h=Subject:To:Cc:From:Date:List-ID:From; b=cq8kDPMp2BOyQmry+KM+KAkiJ4EQCzYpFvFNr8y7ka7nQvCbw/Jhlio//+HxPrD05 +2LcbTvxOUkSqVfnIl2Xk4ajZf230hvShvY1Y6irXuj/9DwcCfCNJm+MLHT46jeKiM e2STF2QC7Z8qdlWJtVKNvUGJCCmnK9puXR5vD3AA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730208AbgFVRvF (ORCPT ); Mon, 22 Jun 2020 13:51:05 -0400 Received: from wforward5-smtp.messagingengine.com ([64.147.123.35]:34675 "EHLO wforward5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730124AbgFVRvE (ORCPT ); Mon, 22 Jun 2020 13:51:04 -0400 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailforward.west.internal (Postfix) with ESMTP id CC32F2F9; Mon, 22 Jun 2020 13:51:03 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute1.internal (MEProxy); Mon, 22 Jun 2020 13:51:03 -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=XnZHsn 0mQG+LEH3G6EFajLxN/ftfD9hmDIP5E/QzzOg=; b=Bv+eyeRdY/kRfbB76acAU6 xPVU8VnLxTCX800L4DCnXcuhXQeTEPkQ/0G+cBD394ulbAW99vcyrcSCeb+4vG7b DNIe6zuT1z9+MYx+lAesEFo99klAwyyqfpMNhIi2K3xDl+BJbpTNTmzsPbJ7XArD 4gbLJJbGFmYsOCILJ79rZYcZzpxYdawMqc7yDMnDh04oK1E5LwX6Niu6OWwLKqGO vrG7AVN5AcjC6dc6RLm7RmNTjtRACutZtxavU3avibQp0yyLs2NVldUbUZ9pZTsF gXP1zeZ11OdabGK1C8RcA8cCPMg/z4jRmYrQPPQqMvu8CxN8ErHLqWmKllfvs/cg == 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 EA22630673D6; Mon, 22 Jun 2020 13:51:02 -0400 (EDT) Subject: FAILED: patch "[PATCH] ext4: avoid race conditions when remounting with options that" failed to apply to 5.4-stable tree To: tytso@mit.edu Cc: From: Date: Mon, 22 Jun 2020 19:50:56 +0200 Message-ID: <159284825626219@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 5.4-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");