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 4E6773984CA; Mon, 5 May 2025 23:07:32 +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=1746486453; cv=none; b=otYisd+WrvGV/lG3foNx1+WiT8/Kj/nPIaSHkh0NScK7UJjh8SzF8DcwUTbPmM5lGhEMrgwic5DPPl5AFKnt39KWdXFqAD3zE/g5Bjsx9SwbarcNY9U+UDGEyxAz5CMNljheCsCax2thN6pisXPTUeVEiOpCCf2g181PWE8v2Lw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746486453; c=relaxed/simple; bh=Cz0GeDrNzh5/LCJk1US0hg0ANTiCkKwOxVTF0992x+s=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=eA3Qxz4GqmVaRQ/A6xebD5/jmlBUseNME8qizVi5owxc5D/o3rol3idZsup+KVXtO/bw8U7Z3fvAj66Oa0eMwuSQpkJ6l5xEjJi6q27LOLBQgazMZ0KHnPTxUdx3PdCH42YeI7em1LRJW3kB86W9E76V0WdZI8AGSQAghq169sw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Uq0I/Hbr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Uq0I/Hbr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3074FC4CEE4; Mon, 5 May 2025 23:07:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746486452; bh=Cz0GeDrNzh5/LCJk1US0hg0ANTiCkKwOxVTF0992x+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Uq0I/HbrT41kzxg/mQYvn01ApEYytdIkZF8CXV1XyHR3q4XZ6iRdS092ydi+D83RK E94KenuI6RVbqo8/Fmr0XKkIviND0gDI7yFfzb5J24GRSg7BPyQlEwXWdLXZ8BNqvW XRpcv54wMxjXUmcKJYOWJLP52fjtVMfluwMMt86MdYuI1qEOQZNecz2zpFy54t/9gZ VncntkZOGXe942lIEYRHZq8Pwj8Sb1ZlO6Jf0OsY3rHvE/4aQ0Q8mEcxQYKQ1fE/Zw OJoLDw2zhnlhSo6HE7ecEgjOHcqRKqHbjukm+rMERGy1juEa5x51PKXM/fVc0B6tV/ MneElcZobuHqA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Filipe Manana , David Sterba , Qu Wenruo , Sasha Levin , clm@fb.com, josef@toxicpanda.com, linux-btrfs@vger.kernel.org Subject: [PATCH AUTOSEL 6.1 037/212] btrfs: fix non-empty delayed iputs list on unmount due to async workers Date: Mon, 5 May 2025 19:03:29 -0400 Message-Id: <20250505230624.2692522-37-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250505230624.2692522-1-sashal@kernel.org> References: <20250505230624.2692522-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.1.136 Content-Transfer-Encoding: 8bit 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 6670188b9eb6b..8c0da0025bc71 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -4669,6 +4669,19 @@ 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