Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763213AbZAQPoj (ORCPT ); Sat, 17 Jan 2009 10:44:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761576AbZAQPo2 (ORCPT ); Sat, 17 Jan 2009 10:44:28 -0500 Received: from mx2.redhat.com ([66.187.237.31]:48719 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761555AbZAQPo1 (ORCPT ); Sat, 17 Jan 2009 10:44:27 -0500 Message-ID: <4971FCCE.3020005@redhat.com> Date: Sat, 17 Jan 2009 09:44:14 -0600 From: Eric Sandeen User-Agent: Thunderbird 2.0.0.19 (Macintosh/20081209) MIME-Version: 1.0 To: 7eggert@gmx.de CC: Eric Sandeen , Valdis.Kletnieks@vt.edu, Andrew Morton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, t-sato@yk.jp.nec.com Subject: Re: [PATCH] Allow SysRq emergency sync to thaw frozen filesystems References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1344 Lines: 31 Bodo Eggert wrote: > Eric Sandeen wrote: >> Valdis.Kletnieks@vt.edu wrote: >>> On Thu, 15 Jan 2009 21:59:10 CST, Eric Sandeen said: > >>>> Oh, actually, I'd think not. If the freeze was done properly by the >>>> filesystem, all data was flushed, the fs was quiesced, and new IO was >>>> blocked. pdflush should never be visiting these... >>> Yes, but a lot of 'if's - and usually you're reaching for sysrq-S precisely >>> *because* you suspect that stuff wasn't happening properly on its own... >> Actually, only one if - if the fs implemented freeze properly. >> >> Well, the use case I envision here is something like: >> >> # freeze /my/mount/point/to/fs/to/snapshot >> >> except oops, that wasn't mounted, and you just froze your root fs. > > Maybe freeze should protect against that by requiring to specify the exact > mountpount, unless you say freeze --subdir? That's a good idea. My "freeze" above was a hypothetical tool which doesn't really exist yet, but should get that enhancement. :) (xfs_freeze does not do this checking today, it probably should) -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/