From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933232Ab3GZVFL (ORCPT ); Fri, 26 Jul 2013 17:05:11 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51404 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760038Ab3GZU62 (ORCPT ); Fri, 26 Jul 2013 16:58:28 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bert De Jonghe , Jan Kara , Jens Axboe Subject: [ 28/45] writeback: Fix periodic writeback after fs mount Date: Fri, 26 Jul 2013 13:57:48 -0700 Message-Id: <20130726205658.015733739@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130726205654.896050165@linuxfoundation.org> References: <20130726205654.896050165@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit a5faeaf9109578e65e1a32e2a3e76c8b47e7dcb6 upstream. Code in blkdev.c moves a device inode to default_backing_dev_info when the last reference to the device is put and moves the device inode back to its bdi when the first reference is acquired. This includes moving to wb.b_dirty list if the device inode is dirty. The code however doesn't setup timer to wake corresponding flusher thread and while wb.b_dirty list is non-empty __mark_inode_dirty() will not set it up either. Thus periodic writeback is effectively disabled until a sync(2) call which can lead to unexpected data loss in case of crash or power failure. Fix the problem by setting up a timer for periodic writeback in case we add the first dirty inode to wb.b_dirty list in bdev_inode_switch_bdi(). Reported-by: Bert De Jonghe Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/block_dev.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -55,13 +55,21 @@ EXPORT_SYMBOL(I_BDEV); static void bdev_inode_switch_bdi(struct inode *inode, struct backing_dev_info *dst) { + bool wakeup_bdi = false; + spin_lock(&inode_wb_list_lock); spin_lock(&inode->i_lock); inode->i_data.backing_dev_info = dst; - if (inode->i_state & I_DIRTY) + if (inode->i_state & I_DIRTY) { + if (bdi_cap_writeback_dirty(dst) && !wb_has_dirty_io(&dst->wb)) + wakeup_bdi = true; list_move(&inode->i_wb_list, &dst->wb.b_dirty); + } spin_unlock(&inode->i_lock); spin_unlock(&inode_wb_list_lock); + + if (wakeup_bdi) + bdi_wakeup_thread_delayed(dst); } sector_t blkdev_max_block(struct block_device *bdev)