From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ted Ts'o Subject: Re: [PATCH 0/2] Re: Discrepancy in 'df' output between kernel 3.0 and 3.2 for ext4? Date: Tue, 19 Jun 2012 16:13:25 -0400 Message-ID: <20120619201325.GE22805@thunk.org> References: <4FD8D731.9070008@cleversafe.com> <1340055909-7683-1-git-send-email-tytso@mit.edu> <4FE0D904.7050401@cleversafe.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ext4 Developers List To: Zachary Mark Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:51382 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753762Ab2FSUN2 (ORCPT ); Tue, 19 Jun 2012 16:13:28 -0400 Content-Disposition: inline In-Reply-To: <4FE0D904.7050401@cleversafe.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Jun 19, 2012 at 02:54:44PM -0500, Zachary Mark wrote: > > Ted, thanks for the patches! I've tested your patches against > 3.5~rc3. I had to return the machine on which I first spotted the > problem, but here are results from a box with identical hardware: > > df from 3.0: > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/sdh1 2907178636 205816 2906972820 1% > /dev/sdi1 2907178636 1056768 2906121868 1% > > df from 3.2.20 (identical to 3.5~rc3 without your patches): > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/sdh1 2928733612 21760792 2906972820 1% > /dev/sdi1 2928733612 22611744 2906121868 1% > > > df from 3.5~rc3 with your patches applied (as they didn't apply to 3.2): > /dev/sdh1 2907178636 205816 2906972820 1% > /dev/sdi1 2907178636 1060936 2906117700 1% > > sdh1 is mostly empty. sdi1 has about 6700 128k files written to it plus > everything on sdh1. There seems to be slightly more overhead accounted > for after your patches. Not sure if this is to be expected or not. Hmm... it looks like df output /dev/sdh1 is identical between 3.0 and 3.5~rc3 with my patches. I'm not sure why there is a difference for /dev/sdi1. However, I note that the "Available" figure is the same between 3.0, 3.2.20 and 3.5~rc3 for /dev/sdh1, but there is a difference in the Available column between 3.2.20 and 3.5~rc3 for /dev/sdi3. Could it be that some files got written to /dev/sdi between your test run? It would be good if we could get this sorted out. I was pretty careful to account for all of the fs overhead blocks between when I did my patch with an empty file system. If this can't be accounted by more files being written to /dev/sdi1, could you send me the (compressed, since they will be large) output of dumpe2fs for /dev/sdh1 and /dev/sdi1 with the "df" output from your three test kernel so I can investigate further? Thanks, - Ted