From: Spelic Subject: Re: Ext4 and xfs problems in dm-thin on allocation and discard Date: Tue, 19 Jun 2012 13:29:55 +0200 Message-ID: <4FE062B3.7080702@shiftmail.org> References: <4FDF9EBE.2030809@shiftmail.org> <20120619015745.GJ25389@dastard> <20120619031241.GA3884@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Mike Snitzer , Dave Chinner , Spelic , device-mapper development , linux-ext4@vger.kernel.org, xfs@oss.sgi.com To: =?windows-1252?Q?Luk=E1=9A_Czerner?= Return-path: Received: from blade3.isti.cnr.it ([194.119.192.19]:2733 "EHLO blade3.isti.cnr.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751863Ab2FSLaW (ORCPT ); Tue, 19 Jun 2012 07:30:22 -0400 Received: from [192.168.6.232] ([155.253.6.254]) by mx.isti.cnr.it (PMDF V6.5-x6 #31988) with ESMTPSA id <01OGVDYYQWV8ODSR3C@mx.isti.cnr.it> for linux-ext4@vger.kernel.org; Tue, 19 Jun 2012 13:29:19 +0200 (MEST) In-reply-to: Sender: linux-ext4-owner@vger.kernel.org List-ID: On 06/19/12 08:32, Luk=E1=9A Czerner wrote: > > So do I understand correctly that even though the discard came > through and thinp took advantage of it it still returns EOPNOTSUPP ? > This seems rather suboptimal. IIRC there was a discussion to add an > option to enable/disable sending discard in thinp target down > to the device. I'll ask this too... do I understand correctly that dm-thin returns EOPNOTSUPP to the=20 filesystem layer even though it is using the discard to unmap blocks,=20 and at that point XFS stops sending discards down there (while ext4=20 keeps sending them)? This looks like a bug of dm-thin to me. Discards are "supported" in suc= h=20 a scenario. Do you have a patch for dm-thin so to prevent it sending EOPTNOTSUPP ? Thank you S. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html