From: Theodore Tso Subject: Re: [RFC][PATCH] Multiple mount protection Date: Fri, 25 May 2007 10:39:57 -0400 Message-ID: <20070525143957.GA12669@thunk.org> References: <1179777153.3910.13.camel@garfield> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4 , Andreas Dilger To: Kalpak Shah Return-path: Received: from thunk.org ([69.25.196.29]:40941 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751938AbXEYOkF (ORCPT ); Fri, 25 May 2007 10:40:05 -0400 Content-Disposition: inline In-Reply-To: <1179777153.3910.13.camel@garfield> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Hi Kalpak, On Tue, May 22, 2007 at 01:22:32AM +0530, Kalpak Shah wrote: > It will also protect against running e2fsck on a mounted filesystem > by adding similar logic to ext2fs_open(). Your patch didn't add this logic to ext2fs_open(); it just reserved the space in the superblock. I don't mind reserving the space so we don't have to worry about conflicting superblock uses, but I'm still on the fence about actually adding this functionality (a) into e2fsprogs, and (b) into the ext4 kernel code. I guess it depends on how complicated/icky the implementation code is, I guess. The question as before is whether the complexity is worth it, given that someone who is actually going to be subject to accidentally mounting an ext3/4 filesystem on multiple systems needs to be using an HA system anyway. So basically this is just to protect against (a) a bug/failure in the HA subsystem, and (b) the idiotic user that failed to realized he/she needed to set up an HA subsystem in the first place. Granted, the universe is going to create idiots at a faster rate that we can deal with it, but that's why I'm still not 100% convinced the complexity is worth it. To be fair, if I was on a L3 support team having to deal with these idiots, I'd probably feel differently. :-) - Ted