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 9A7821E89C; Tue, 27 May 2025 17:24:12 +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=1748366652; cv=none; b=rY3BNu0jBvn9rZq6H9NrkELGxMD/4q7oXoOyxlJX52figut6PHl2Q2vRedqkiuBYfoK7Dh7jHY67bitbwVdsSS/Ga9NsgTo0LkwwhIxkPnNYFEUYz9GOZlvTLDbmHXKxQRwedv7W0DBbm/YPk5a8dlR3kPgcFGR//l9t4WXOkjY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748366652; c=relaxed/simple; bh=lGKsnkLEzS+nKrsbIyit0GjbCgiipqwsgbfovH1l2fM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Qx8htObHU+H8XzBQxOArk2SI1NpODn3+xD4fOj4EM4U/5jyBn+19G68LS1DpbPdDgSmL/nyAQ0FU48fUuLBDHDkYXppQlB20dxl33w80Q8frDXAJb5WHuI07bHiZa3zMuELD9iPj8L+rSwVHcLMaktT0vAKEAQZ0ZvMrX8FgTaU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YEJX8QDF; 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="YEJX8QDF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2781C4CEF4; Tue, 27 May 2025 17:24:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748366652; bh=lGKsnkLEzS+nKrsbIyit0GjbCgiipqwsgbfovH1l2fM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YEJX8QDF+YuFskhc0piBPwapTaqpH7EzzitSDxhJPIF2/3jFm1C2vrGVZkNOFTNNy LV3AOM9HACIB1BNpdCY6s2kcnIYbivw7flvWdHQmW+ndYXJ5i/oimvgSTuDAOTakDp v28Ny4baH5P8ptJUpVXbFrcxn19GeqMNLH8ZClOg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Sterba , Qu Wenruo , Filipe Manana , Sasha Levin Subject: [PATCH 6.14 137/783] btrfs: fix non-empty delayed iputs list on unmount due to async workers Date: Tue, 27 May 2025 18:18:54 +0200 Message-ID: <20250527162518.739662435@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250527162513.035720581@linuxfoundation.org> References: <20250527162513.035720581@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Filipe Manana [ Upstream commit cda76788f8b0f7de3171100e3164ec1ce702292e ] At close_ctree() after we have ran delayed iputs either explicitly through calling btrfs_run_delayed_iputs() or later during the call to btrfs_commit_super() or btrfs_error_commit_super(), we assert that the delayed iputs list is empty. We have (another) race where this assertion might fail because we have queued an async write into the fs_info->workers workqueue. Here's how it happens: 1) We are submitting a data bio for an inode that is not the data relocation inode, so we call btrfs_wq_submit_bio(); 2) btrfs_wq_submit_bio() submits a work for the fs_info->workers queue that will run run_one_async_done(); 3) We enter close_ctree(), flush several work queues except fs_info->workers, explicitly run delayed iputs with a call to btrfs_run_delayed_iputs() and then again shortly after by calling btrfs_commit_super() or btrfs_error_commit_super(), which also run delayed iputs; 4) run_one_async_done() is executed in the work queue, and because there was an IO error (bio->bi_status is not 0) it calls btrfs_bio_end_io(), which drops the final reference on the associated ordered extent by calling btrfs_put_ordered_extent() - and that adds a delayed iput for the inode; 5) At close_ctree() we find that after stopping the cleaner and transaction kthreads the delayed iputs list is not empty, failing the following assertion: ASSERT(list_empty(&fs_info->delayed_iputs)); Fix this by flushing the fs_info->workers workqueue before running delayed iputs at close_ctree(). David reported this when running generic/648, which exercises IO error paths by using the DM error table. Reported-by: David Sterba Reviewed-by: Qu Wenruo Signed-off-by: Filipe Manana Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/disk-io.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index e4eda8b0f9381..cc8d736937012 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -4356,6 +4356,19 @@ void __cold close_ctree(struct btrfs_fs_info *fs_info) */ btrfs_flush_workqueue(fs_info->delalloc_workers); + /* + * We can have ordered extents getting their last reference dropped from + * the fs_info->workers queue because for async writes for data bios we + * queue a work for that queue, at btrfs_wq_submit_bio(), that runs + * run_one_async_done() which calls btrfs_bio_end_io() in case the bio + * has an error, and that later function can do the final + * btrfs_put_ordered_extent() on the ordered extent attached to the bio, + * which adds a delayed iput for the inode. So we must flush the queue + * so that we don't have delayed iputs after committing the current + * transaction below and stopping the cleaner and transaction kthreads. + */ + btrfs_flush_workqueue(fs_info->workers); + /* * When finishing a compressed write bio we schedule a work queue item * to finish an ordered extent - btrfs_finish_compressed_write_work() -- 2.39.5