From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mosis Tembo Subject: Re: Tux3 Report: How fast can we fail? Date: Wed, 27 May 2015 17:21:24 +0200 Message-ID: <5565E0F4.1050403@gmail.com> References: <8f886f13-6550-4322-95be-93244ae61045@phunq.net> <55523C88.9080809@phunq.net> <20150526100326.GA8854@amd> <55657446.40805@gmail.com> <5565CF03.9010202@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit To: Austin S Hemmelgarn , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Return-path: Received: from mail-wi0-f174.google.com ([209.85.212.174]:38244 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752870AbbE0PV1 (ORCPT ); Wed, 27 May 2015 11:21:27 -0400 In-Reply-To: <5565CF03.9010202@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 05/27/2015 04:04 PM, Austin S Hemmelgarn wrote: > On 2015-05-27 03:37, Mosis Tembo wrote: >> >> On 05/26/2015 12:03 PM, Pavel Machek wrote: >>>> We identified the following quality metrics for this algorithm: >>>> >>>> 1) Never fails to detect out of space in the front end. >>>> 2) Always fills a volume to 100% before reporting out of space. >>>> 3) Allows rm, rmdir and truncate even when a volume is full. >> >> This is definitely nonsense. You can not rm, rmdir and truncate >> when the volume is full. You will need a free space on disk to perform >> such operations. Do you know why? >> > I assume you are referring either to Tux3 specifically or COW > filesystems in general, I am referring to modern file systems with transaction models and delayed actions. Tux3 is not the case? > because you very much _can_ do any of those on any of the non-COW > filesystems in the Linux kernel It is simply incorrect. ReiserFS is a counterexample. > (I know from experience). Also, IIRC, it was mentioned somewhere that > Tux3 keeps a small reserve of space on the volume for internal > operations; and, I would assume that if that is the case, it reports > the volume full when everything *except* that reserve of space is > used, in which case rm, rmdir, and truncate should work fine when the > volume is full. Sorry, I prefer to not manipulate with rumors and assumptions when it comes to the review for kernel inclusion. Thanks, M.T.