From patchwork Tue Mar 3 18:02:47 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jaegeuk Kim X-Patchwork-Id: 5925381 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 2067BBF440 for ; Tue, 3 Mar 2015 18:04:14 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 32DE12034F for ; Tue, 3 Mar 2015 18:04:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8BBA120320 for ; Tue, 3 Mar 2015 18:04:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756663AbbCCSCz (ORCPT ); Tue, 3 Mar 2015 13:02:55 -0500 Received: from mail.kernel.org ([198.145.29.136]:39223 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755221AbbCCSCy (ORCPT ); Tue, 3 Mar 2015 13:02:54 -0500 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 66146202EC; Tue, 3 Mar 2015 18:02:53 +0000 (UTC) Received: from localhost (unknown [166.170.43.88]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3D11D202E5; Tue, 3 Mar 2015 18:02:52 +0000 (UTC) From: Jaegeuk Kim To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: Jaegeuk Kim Subject: [PATCH 1/3] f2fs: avoid to trigger writepage during POR Date: Tue, 3 Mar 2015 10:02:47 -0800 Message-Id: <1425405769-92563-1-git-send-email-jaegeuk@kernel.org> X-Mailer: git-send-email 2.1.1 X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch doesn't make any effect on previous behavior, since f2fs_write_data_page bypasses writing the page during POR. But, the difference is that this patch avoids holding writepages mutex. This is to avoid the following false warning, since this can happen only when mount and shutdown are triggered at the same time. ====================================================== [ INFO: possible circular locking dependency detected ] 4.0.0-rc1+ #3 Tainted: G O ------------------------------------------------------- kworker/u8:0/2270 is trying to acquire lock: (&sbi->gc_mutex){+.+.+.}, at: [] f2fs_balance_fs+0x73/0x90 [f2fs] but task is already holding lock: (&sbi->writepages){+.+...}, at: [] f2fs_write_data_pages+0xcb/0x3a0 [f2fs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sbi->writepages){+.+...}: [] lock_acquire+0xe1/0x2f0 [] mutex_lock_nested+0x63/0x530 [] f2fs_write_data_pages+0xcb/0x3a0 [f2fs] [] do_writepages+0x21/0x50 [] __writeback_single_inode+0x76/0xbf0 [] writeback_single_inode+0xea/0x1c0 [] write_inode_now+0x95/0xa0 [] iput+0x20b/0x3f0 [] recover_data.constprop.14+0x26b/0xa80 [f2fs] [] recover_fsync_data+0x2b6/0x5e0 [f2fs] [] f2fs_fill_super+0xb24/0xb90 [f2fs] [] mount_bdev+0x1a4/0x1e0 [] f2fs_mount+0x15/0x20 [f2fs] [] mount_fs+0x39/0x180 [] vfs_kern_mount+0x6b/0x160 [] do_mount+0x204/0xbe0 [] SyS_mount+0x8b/0xe0 [] system_call_fastpath+0x16/0x1b -> #1 (&sbi->cp_mutex){+.+...}: [] lock_acquire+0xe1/0x2f0 [] mutex_lock_nested+0x63/0x530 [] write_checkpoint+0x42/0x1230 [f2fs] [] f2fs_sync_fs+0x9d/0x2a0 [f2fs] [] sync_filesystem+0x82/0xb0 [] generic_shutdown_super+0x34/0x100 [] kill_block_super+0x27/0x70 [] kill_f2fs_super+0x20/0x30 [f2fs] [] deactivate_locked_super+0x49/0x80 [] deactivate_super+0x4e/0x70 [] cleanup_mnt+0x43/0x90 [] __cleanup_mnt+0x12/0x20 [] task_work_run+0xc4/0xf0 [] do_notify_resume+0x8d/0xa0 [] int_signal+0x12/0x17 -> #0 (&sbi->gc_mutex){+.+.+.}: [] __lock_acquire+0x1ac6/0x1c90 [] lock_acquire+0xe1/0x2f0 [] mutex_lock_nested+0x63/0x530 [] f2fs_balance_fs+0x73/0x90 [f2fs] [] f2fs_write_data_page+0x348/0x5b0 [f2fs] [] __f2fs_writepage+0x1a/0x50 [f2fs] [] write_cache_pages+0x274/0x6f0 [] f2fs_write_data_pages+0xe0/0x3a0 [f2fs] [] do_writepages+0x21/0x50 [] __writeback_single_inode+0x76/0xbf0 [] writeback_sb_inodes+0x32a/0x710 [] __writeback_inodes_wb+0x9f/0xd0 [] wb_writeback+0x3db/0x850 [] bdi_writeback_workfn+0x148/0x980 [] process_one_work+0x1e2/0x840 [] worker_thread+0x121/0x460 [] kthread+0xf8/0x110 [] ret_from_fork+0x7c/0xb0 Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 389fda7..0057d4b 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1408,6 +1408,10 @@ static int f2fs_write_data_pages(struct address_space *mapping, available_free_memory(sbi, DIRTY_DENTS)) goto skip_write; + /* during POR, we don't need to trigger writepage at all. */ + if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING))) + goto skip_write; + diff = nr_pages_to_write(sbi, DATA, wbc); if (!S_ISDIR(inode->i_mode)) {