From: Lukas Czerner Subject: Re: Feature request: e2fsck -z Date: Wed, 10 Aug 2011 13:09:47 +0200 (CEST) Message-ID: References: <4E4173D4.9010104@zytor.com> <4E422686.8080207@gmail.com> <4420E0D8-5E16-4FD0-A7A9-B462F02D742D@dilger.ca> <4E423FD0.40108@gmail.com> <82k4ala62o.fsf@mid.bfk.de> <82fwl9a5o5.fsf@mid.bfk.de> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Lukas Czerner , Ric Wheeler , Andreas Dilger , "H. Peter Anvin" , linux-ext4@vger.kernel.org To: Florian Weimer Return-path: Received: from mx1.redhat.com ([209.132.183.28]:62336 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752796Ab1HJLJy (ORCPT ); Wed, 10 Aug 2011 07:09:54 -0400 In-Reply-To: <82fwl9a5o5.fsf@mid.bfk.de> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, 10 Aug 2011, Florian Weimer wrote: > * Lukas Czerner: > > > On Wed, 10 Aug 2011, Florian Weimer wrote: > > > >> * Lukas Czerner: > >> > >> > You're right. It is a part of e2fsck and you can enable it with -E > >> > discard. > >> > >> If the block device does not support TRIM, does this result in zeros > >> being written instead? > > > Of course not, discard works only on devices which does support it. If > > the device does not support discard it will to nothing. > > Oh, then it doesn't address hpa's use case (improving compression). > It does if he will use SSD's with "discard_zeroes_data" capability. But my original answer was to simply confirm that e2fsck has that feature. Thanks! -Lukas