From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: Commit Interval and Delayed Allocation Date: Fri, 9 Nov 2012 21:58:38 -0500 Message-ID: <20121110025838.GA5974@thunk.org> References: <0408C81F72528E40A0D3235A1F67FFC83ECD9881@SN2PRD0202MB144.namprd02.prod.outlook.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "linux-ext4@vger.kernel.org" To: "Nelson, John R" Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:60318 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750810Ab2KJC6l (ORCPT ); Fri, 9 Nov 2012 21:58:41 -0500 Content-Disposition: inline In-Reply-To: <0408C81F72528E40A0D3235A1F67FFC83ECD9881@SN2PRD0202MB144.namprd02.prod.outlook.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sat, Nov 10, 2012 at 12:40:42AM +0000, Nelson, John R wrote: > Hi, > Say if ext4 commits every 5 seconds, does this mean whatever is >buffered for delayed allocation is flushed every 5 seconds as well? No; there is a separate 30 second timer which is used for writeback thread. For ext3 in data=ordered mode, we will flush out dirty pages for inodes which have been written to make sure that stale data can never get revealed. But in delayed allocation, there is no risk that stale data can get revealed until we actually allocate the data blocks. - Ted