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Mon, 16 Mar 2026 12:33:07 -0700 (PDT) Received: from smtpclient.apple ([128.107.241.172]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2c0bfd41aacsm8334565eec.27.2026.03.16.12.33.07 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 16 Mar 2026 12:33:07 -0700 (PDT) From: Shramana Chakraborty Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3774.600.62\)) Date: Mon, 16 Mar 2026 12:32:56 -0700 Subject: Warning Trace seen at https://elixir.bootlin.com/linux/v6.6.69/source/fs/ext4/ext4_jbd2.c#L73 post remount-ro Message-Id: To: tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org X-Mailer: Apple Mail (2.3774.600.62) Hi All, I am following up on this bug, = https://bugzilla.kernel.org/show_bug.cgi?id=3D220299, I raised last year = regarding warning traces seen during systemd shutdown. Warning Trace seen at = https://elixir.bootlin.com/linux/v6.6.69/source/fs/ext4/ext4_jbd2.c#L73 = is hit by the writeback system even though there is nothing to write and = the filesystem has been mounted as readonly.=20 An ext4 fs is mounted with journal=3Ddata and a large file is written to = it. Then the fs is mounted as readonly-ro post a sync. At this point of = time, data consistency is preserved through the sync itself followed by = a sync from the remount-ro action.=20 All the dirty pages should be marked as clean in the cache. Yet post the = remount-ro, it hits = https://elixir.bootlin.com/linux/v6.6.69/source/fs/ext4/ext4_jbd2.c#L73 = and prints the trace as the fs is readonly now.=20 Even though there is nothing to writeback, the wb_writeback is scheduled = every 5 secs or so and the same trace can be seen if changed from = WARN_ON_ONCE to WARN_ON. I found that this was reported earlier as well via = https://lkml.org/lkml/2024/5/17/983.=20 This is still seen on 6.6.x LTS kernel with rootfs mounted with = data=3Djournal option. I wonder whether/how this could be addressed. Thanks and Regards Shramana Chakraborty=