From: Eric Sandeen Subject: Re: [PATCH] mke2fs: restore verbose message for BLKDISCARD Date: Mon, 11 Mar 2013 09:08:20 -0500 Message-ID: <513DE554.6020508@redhat.com> References: <1362515118-30344-1-git-send-email-swarren@wwwdotorg.org> <5138EEBD.5000705@wwwdotorg.org> <513A1D56.1010402@wwwdotorg.org> <20130308190019.GB12008@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Stephen Warren , =?windows-1252?Q?Luk=E1=9A_?= =?windows-1252?Q?Czerner?= , Chris Ball , linux-ext4@vger.kernel.org, Stephen Warren To: "Theodore Ts'o" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:62280 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752479Ab3CKOIY (ORCPT ); Mon, 11 Mar 2013 10:08:24 -0400 In-Reply-To: <20130308190019.GB12008@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 3/8/13 1:00 PM, Theodore Ts'o wrote: > I hate to suggest this, but there's so many crappy devices out there > that I'm wondering if we need to figure out some way of maintaining a > black list of devices that don't handle discard properly. For > example, the Sandisk U100 advertises a max discard granularity of 512 > bytes, but I've been advised that if you don't use a discard > granularity of 256k, aligned on 256k, you'll be very, very, sorry. > It sounds like Stephen's device is probably an example of Yet Another > Busted Trim implementation. The problem is that manufacturers will be > releasing more broken products faster than we can update a blacklist > in the kernel. So any blacklist would have to be maintained online on > the web, and dynamically updated by distro installers. :-( Yeah I think it may be time for a blacklist. TBH I think we should revisit discard-at-mkfs-time by default as well. It seemed like a decent idea at the time, but now we have handy fstrim as well as online/dynamic/realtime trim, and trim at mkfs makes mke2fs completely un-doable in the event of fat fingers. -Eric > > - Ted > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >