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 723151DE881; Mon, 2 Jun 2025 14:08:52 +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=1748873332; cv=none; b=fBvECBWTkXeDIs7kJ4sSqDewcUwLYQad2aKSVb+Q/3eAeISGfvKnzNtYuKT6ttOWZ1EFdYpe+udvzHilSkTq6Ta+zqkYuZ3/6Mq6IGNc7M8XruNpNXnCaJ8ZQqUcAcN8kLTDa5pJ8dE4YftkBDLmIIVCaavI8ojBMxbUGe3Km1A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748873332; c=relaxed/simple; bh=icP6gA02admpb+7oEGnojsDy1FeGQ16qgKN7vQ2fIC0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ARqTAdpaVQe93Jn+dNxbXlFtPA0EvtbCVyAKgQEs2gleNmjFGC40Rz0/+5D91Fg5KEecHRvk/0/EmquAvlC7oWIBGeBMsuVncdafJgmeYVUHHDQt5ao8Xw9B0NhrecySVxWfZRzaI6M2ifauzfB/tDxJu5uflWBOrr4Kapf9yDg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nRH3mqxW; 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="nRH3mqxW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD7F2C4CEEB; Mon, 2 Jun 2025 14:08:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748873332; bh=icP6gA02admpb+7oEGnojsDy1FeGQ16qgKN7vQ2fIC0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nRH3mqxWa6+qRYxaA/Lgm0teIVazuToyiPrnRbo8Fj2ORMncrE355h7BgZ+I2SlQ7 hI8udZvCPEEHe0QQxpup3wCbDiHP3zEk5s8K55Bn7QAfV/rZW3tHB4mJuIBFGN6hjf uNUezz3W3rj8tx7Aot4CkTFluRJ5mGdePrnPUdWs= 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 6.6 078/444] btrfs: fix non-empty delayed iputs list on unmount due to async workers Date: Mon, 2 Jun 2025 15:42:22 +0200 Message-ID: <20250602134344.074684379@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250602134340.906731340@linuxfoundation.org> References: <20250602134340.906731340@linuxfoundation.org> User-Agent: quilt/0.68 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: 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 1e1650012606e..34a30d61b470c 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -4341,6 +4341,19 @@ 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