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 41B8C145A16; Fri, 6 Dec 2024 15:21:31 +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=1733498491; cv=none; b=PZw33uFbVtxB1vp5Lg0CIgC2T5DcWIuBG85lM7iBvHYq1LXYqqiWunileenEruP/oMsCry0xKLZjtckzzCL52rrDMcS4sZAsA1d2tdP+mCvI+dXpAjXfPgN4e4xqeewUWf3OfiA0DZcOs03mgNdgS3xfieK8HuWUaKyX/Ax0fLY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733498491; c=relaxed/simple; bh=7IEEgD0PRM0ud92/dywnOhgv4zGNItNw/KiqxhMrFL4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cvSR00TeaPvUIlcIdVp0QntvhDG9CqMJpHRm/CpJHswd+BbNlbw+D6rnn7zTG8ro+g1eOWG0c0SUZp/XY5N2n4ClKZ25QiQcB5tZXRpMrhe96FUqGtxtTus3t1KTLoJ99yy2d7qvRysqLzeWY5tOEi3UpOjX7kIKE3M+bChlaAk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=grbFKxsI; 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="grbFKxsI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9FF4AC4CED1; Fri, 6 Dec 2024 15:21:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1733498491; bh=7IEEgD0PRM0ud92/dywnOhgv4zGNItNw/KiqxhMrFL4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=grbFKxsIZ68CeFMXjT6WsOsBVScFoMlSEJPoEg6dwkJEwa0kxkh8cu6qMfxOyBuyY 2Zo5ohXctQqXBmztbGTMeTrSzPyCirx5cFWZanQNNRs3ObOEKt8bLz2vuNfGtpklc1 HDra6sophTrI1xtGHNnIJBNxYZnOXVfyrjsBQr0g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Disha Goel , Baokun Li , Ojaswin Mujoo , Jan Kara , Sasha Levin Subject: [PATCH 6.6 601/676] quota: flush quota_release_work upon quota writeback Date: Fri, 6 Dec 2024 15:37:00 +0100 Message-ID: <20241206143716.846124819@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241206143653.344873888@linuxfoundation.org> References: <20241206143653.344873888@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ojaswin Mujoo [ Upstream commit ac6f420291b3fee1113f21d612fa88b628afab5b ] One of the paths quota writeback is called from is: freeze_super() sync_filesystem() ext4_sync_fs() dquot_writeback_dquots() Since we currently don't always flush the quota_release_work queue in this path, we can end up with the following race: 1. dquot are added to releasing_dquots list during regular operations. 2. FS Freeze starts, however, this does not flush the quota_release_work queue. 3. Freeze completes. 4. Kernel eventually tries to flush the workqueue while FS is frozen which hits a WARN_ON since transaction gets started during frozen state: ext4_journal_check_start+0x28/0x110 [ext4] (unreliable) __ext4_journal_start_sb+0x64/0x1c0 [ext4] ext4_release_dquot+0x90/0x1d0 [ext4] quota_release_workfn+0x43c/0x4d0 Which is the following line: WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE); Which ultimately results in generic/390 failing due to dmesg noise. This was detected on powerpc machine 15 cores. To avoid this, make sure to flush the workqueue during dquot_writeback_dquots() so we dont have any pending workitems after freeze. Reported-by: Disha Goel CC: stable@vger.kernel.org Fixes: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") Reviewed-by: Baokun Li Signed-off-by: Ojaswin Mujoo Signed-off-by: Jan Kara Link: https://patch.msgid.link/20241121123855.645335-2-ojaswin@linux.ibm.com Signed-off-by: Sasha Levin --- fs/quota/dquot.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index 23dbde1de2520..67562c78e57d5 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -690,6 +690,8 @@ int dquot_writeback_dquots(struct super_block *sb, int type) WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount)); + flush_delayed_work("a_release_work); + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (type != -1 && cnt != type) continue; -- 2.43.0