From: Mark Lord Subject: Re: [PATCH 2/2] Add batched discard support for ext4. Date: Mon, 26 Apr 2010 10:00:36 -0400 Message-ID: <4BD59C84.4040200@teksavvy.com> References: <1271674527-2977-1-git-send-email-lczerner@redhat.com> <4BD2F69D.7070508@redhat.com> <4BD30393.4050800@redhat.com> <4BD324B5.4030808@redhat.com> <4BD33B61.2080807@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Greg Freemyer , Eric Sandeen , Lukas Czerner , Jeff Moyer , linux-ext4@vger.kernel.org, Edward Shishkin , Eric Sandeen , Christoph Hellwig To: Ric Wheeler Return-path: Received: from ironport2-out.teksavvy.com ([206.248.154.183]:38857 "EHLO ironport2-out.pppoe.ca" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751290Ab0DZOKP (ORCPT ); Mon, 26 Apr 2010 10:10:15 -0400 In-Reply-To: <4BD33B61.2080807@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 24/04/10 02:41 PM, Ric Wheeler wrote: .. > I don't like the user space wiper.sh approach in general, but running > wiper.sh is entirely your choice. > > Most users prefer having the file system and the IO stack take care of > this for them, but again, entirely configurable. .. I wrote wiper.sh, and I would prefer more of an in-kernel solution, simply because it could potentially have the smarts to deal with RAID, LVM, and btrfs's own duplicate implementation of RAID/LVM. Those cannot be done from userspace on a mounted filesystem. So.. again.. in an ideal kernel, I'd like to see use of larger ranges (and _multiple_ ranges) per TRIM command. And options for the kernel to do it automatically (-o discard), as well as an ioctl() interface for userspace to "scrub" (or "wipe") all free ranges in a gradual fashion. Cheers