From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7736C27A130 for ; Mon, 29 Dec 2025 12:23:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767010986; cv=none; b=MQlfDOuQkWgTcwyxZ2JfwK4bOgOgXk93ZZTw1lWwlEMz36o1yVcZpHDu1Kv7vqq3gBzEsVlB4d1BGn9mgtKOxz2QmAQnUjf59HjY0uCCKyWGemSQMpGhxmglxw4xrYtZm5XeOHBH3Q3EmCSd6H01gOVeSauOTjbGIxYFzd4PqRY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767010986; c=relaxed/simple; bh=jMXVJmXK0lfgIJVC1M5ach5tdS5b1xlPygrodgY3Un8=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=htCIps0KjZOwFgICniIhl+/AIPpt6MV21RX92ZrkLJW2WzrtBJ3vgeFGJFTJLSfVBh0m4je+0iKQ2fHdo4mRkWn3Pdz1qKBIjnVeR1c8DfSvJQkMS0vnE9Yn4Cu4K6TCr/ddI4sIN5hbo+JZifzGliHN0CJuT/s9QFkgHpyc3P4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1swL8NCy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1swL8NCy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F1C8C4CEF7; Mon, 29 Dec 2025 12:23:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767010984; bh=jMXVJmXK0lfgIJVC1M5ach5tdS5b1xlPygrodgY3Un8=; h=Subject:To:Cc:From:Date:From; b=1swL8NCyD3V7WgGQkAYaoHznZA4urRxL16HLEaDWm9PvpS4zUobDBT2yjoR12bUi9 zVR22XqVUYgyY3nA6e+YJcu5EUb4DvpIl1KkG08bbBe/pJUeBc/1p5nsGOBhE3C5e0 h4zm+lR9PB8GDScgnPS93tPIekmr+E209kT8yYQs= Subject: FAILED: patch "[PATCH] jbd2: fix the inconsistency between checksum and data in" failed to apply to 6.6-stable tree To: yebin10@huawei.com,djwong@kernel.org,jack@suse.cz,libaokun1@huawei.com,tytso@mit.edu Cc: From: Date: Mon, 29 Dec 2025 13:23:01 +0100 Message-ID: <2025122901-exciting-strained-363f@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-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 . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 6abfe107894af7e8ce3a2e120c619d81ee764ad5 # git commit -s git send-email --to '' --in-reply-to '2025122901-exciting-strained-363f@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 6abfe107894af7e8ce3a2e120c619d81ee764ad5 Mon Sep 17 00:00:00 2001 From: Ye Bin Date: Mon, 3 Nov 2025 09:01:23 +0800 Subject: [PATCH] jbd2: fix the inconsistency between checksum and data in memory for journal sb Copying the file system while it is mounted as read-only results in a mount failure: [~]# mkfs.ext4 -F /dev/sdc [~]# mount /dev/sdc -o ro /mnt/test [~]# dd if=/dev/sdc of=/dev/sda bs=1M [~]# mount /dev/sda /mnt/test1 [ 1094.849826] JBD2: journal checksum error [ 1094.850927] EXT4-fs (sda): Could not load journal inode mount: mount /dev/sda on /mnt/test1 failed: Bad message The process described above is just an abstracted way I came up with to reproduce the issue. In the actual scenario, the file system was mounted read-only and then copied while it was still mounted. It was found that the mount operation failed. The user intended to verify the data or use it as a backup, and this action was performed during a version upgrade. Above issue may happen as follows: ext4_fill_super set_journal_csum_feature_set(sb) if (ext4_has_metadata_csum(sb)) incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3; if (test_opt(sb, JOURNAL_CHECKSUM) jbd2_journal_set_features(sbi->s_journal, compat, 0, incompat); lock_buffer(journal->j_sb_buffer); sb->s_feature_incompat |= cpu_to_be32(incompat); //The data in the journal sb was modified, but the checksum was not updated, so the data remaining in memory has a mismatch between the data and the checksum. unlock_buffer(journal->j_sb_buffer); In this case, the journal sb copied over is in a state where the checksum and data are inconsistent, so mounting fails. To solve the above issue, update the checksum in memory after modifying the journal sb. Fixes: 4fd5ea43bc11 ("jbd2: checksum journal superblock") Signed-off-by: Ye Bin Reviewed-by: Baokun Li Reviewed-by: Darrick J. Wong Reviewed-by: Jan Kara Message-ID: <20251103010123.3753631-1-yebin@huaweicloud.com> Signed-off-by: Theodore Ts'o Cc: stable@kernel.org diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 2fe1786a8f1b..c973162d5b31 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -2354,6 +2354,12 @@ int jbd2_journal_set_features(journal_t *journal, unsigned long compat, sb->s_feature_compat |= cpu_to_be32(compat); sb->s_feature_ro_compat |= cpu_to_be32(ro); sb->s_feature_incompat |= cpu_to_be32(incompat); + /* + * Update the checksum now so that it is valid even for read-only + * filesystems where jbd2_write_superblock() doesn't get called. + */ + if (jbd2_journal_has_csum_v2or3(journal)) + sb->s_checksum = jbd2_superblock_csum(sb); unlock_buffer(journal->j_sb_buffer); jbd2_journal_init_transaction_limits(journal); @@ -2383,9 +2389,17 @@ void jbd2_journal_clear_features(journal_t *journal, unsigned long compat, sb = journal->j_superblock; + lock_buffer(journal->j_sb_buffer); sb->s_feature_compat &= ~cpu_to_be32(compat); sb->s_feature_ro_compat &= ~cpu_to_be32(ro); sb->s_feature_incompat &= ~cpu_to_be32(incompat); + /* + * Update the checksum now so that it is valid even for read-only + * filesystems where jbd2_write_superblock() doesn't get called. + */ + if (jbd2_journal_has_csum_v2or3(journal)) + sb->s_checksum = jbd2_superblock_csum(sb); + unlock_buffer(journal->j_sb_buffer); jbd2_journal_init_transaction_limits(journal); } EXPORT_SYMBOL(jbd2_journal_clear_features);