From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-15?Q?Luk=E1=A8_Czerner?= Subject: Re: [PATCH] mke2fs: disable resize_inode feature if 64bit feature is enabled Date: Thu, 6 Mar 2014 15:03:30 +0100 (CET) Message-ID: References: <1372928710-10461-1-git-send-email-guaneryu@gmail.com> <20130705012128.GA11793@gmail.com> <20130707154140.GA11993@thunk.org> <20140304151925.GC23106@thunk.org> Mime-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="8323328-1940693645-1394114612=:2249" Cc: Eryu Guan , linux-ext4@vger.kernel.org To: "Theodore Ts'o" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:54441 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751808AbaCFODi (ORCPT ); Thu, 6 Mar 2014 09:03:38 -0500 In-Reply-To: <20140304151925.GC23106@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323328-1940693645-1394114612=:2249 Content-Type: TEXT/PLAIN; charset=utf-8 Content-Transfer-Encoding: 8BIT On Tue, 4 Mar 2014, Theodore Ts'o wrote: > Date: Tue, 4 Mar 2014 10:19:25 -0500 > From: Theodore Ts'o > To: Lukáš Czerner > Cc: Eryu Guan , linux-ext4@vger.kernel.org > Subject: Re: [PATCH] mke2fs: disable resize_inode feature if 64bit feature is > enabled > > On Mon, Mar 03, 2014 at 04:40:21PM +0100, Lukáš Czerner wrote: > > > > are you going to take this in ? > > > > > It's better to use the resize_inode for file systems that are smaller > > > than 16TB, even if the 64-bit flag is enabled, since using the meta_bg > > > style resizing spreads out the block group descriptors, which > > > increases the time to mount the file system. Using the resize_inode > > > will defer the need to go to the meta_bg-style resizing until we cross > > > the 16TB boundary. > > See my comments above. > > If we create a file system which is say, 1T but with the 64-bit flag, > we do want the resize_inode feature to be used until we cross over the > 32-bit boundary, because keeping block group descriptors contiguous > speeds up the mount time. > > If I were to accept this patch, and/or Red Hat were to ship with it, I > will predict that you will get angry customer support calls about file > system mount times getting slow after doing a resize. > > At some point what we may want to lazily load the block group > descriptors at mount time, to mitigate the slow mount time issue when > using meta_bg. We have a lot of assumptions in the code that the > block group descriptors are always available, though. > > - Ted Hi Ted, I am sorry, but am I missing something ? This patch seems to do exactly that. if ((fs_blocks_count > MAX_32_NUM) && + (fs_param.s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT)) + fs_param.s_feature_compat &= ~EXT2_FEATURE_COMPAT_RESIZE_INODE; The answer from you on that patch is commenting on a guestion from Zheng Liu who is asking whether we could skip the MAX_32_NUM check. So the patch seems to be ok for me. Thanks! -Lukas --8323328-1940693645-1394114612=:2249--