From: Tao Ma Subject: Re: [PATCH] ext4: Protect group inode free counting with group lock. Date: Tue, 29 May 2012 22:28:34 +0800 Message-ID: <4FC4DD12.4020007@tao.ma> References: <1337158192-4591-1-git-send-email-tm@tao.ma> <4FB3AF00.9060704@redhat.com> <4FB3BFC9.20901@tao.ma> <4FB3CC8C.4030502@redhat.com> <4FB45FBE.10004@tao.ma> <20120528222241.GD5610@thunk.org> <4FC431E6.7020206@tao.ma> <8932CA1F-B08D-4327-AD23-38EA56D49F47@dilger.ca> <20120529123950.GC16351@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Andreas Dilger , Eric Sandeen , linux-ext4@vger.kernel.org To: Ted Ts'o Return-path: Received: from oproxy6-pub.bluehost.com ([67.222.54.6]:57632 "HELO oproxy6-pub.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753506Ab2E2O2n (ORCPT ); Tue, 29 May 2012 10:28:43 -0400 In-Reply-To: <20120529123950.GC16351@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 05/29/2012 08:39 PM, Ted Ts'o wrote: > On Mon, May 28, 2012 at 11:57:59PM -0600, Andreas Dilger wrote: >>> We are just disabling the uninit_bg so as to let the block group >>> initialization happen in the mkfs time. I don't know why the checksum is >>> also disabled by ^uninit_bg. >> >> The checksum is controlled by uninit_bg, because there was a need to >> ensure the bg_itable_unused count and the UNINIT flags could be >> trusted when doing an e2fsck. >> >> If you don't want to do lazy inode table initialization, that is >> disabled by "mke2fs -E lazy_itable_init=0". > > You can also disable whether or not lazy inode table initialization > happens by default via /etc/mke2fs.conf. At work we have a very > fairly havily modified /etc/mke2fs.conf which has our > production-specific mke2fs parameters defined, so that someone who > runs mke2fs by hand will get the same result at as the automated > systems. > > I can easily see how if you are trying for predictable latency > numbers, disabling lazy inode table initialization makes a huge amount > of sense. I'd recommend doing it via /etc/mke2fs.conf, though. OK, thank you all for the good suggestion. Thanks Tao