From: Christoph Hellwig Subject: Re: [PATCH 3/3] Add timeout feature Date: Mon, 29 Sep 2008 10:37:49 -0400 Message-ID: <20080929143749.GA13286@infradead.org> References: <20080908205337t-sato@mail.jp.nec.com> <20080908171119.GB22521@infradead.org> <48DBFD42.6030307@redhat.com> <20080929141326.GA31781@infradead.org> <48E0E7D4.1090409@sandeen.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Christoph Hellwig , Takashi Sato , Ric Wheeler , Andrew Morton , Oleg Nesterov , linux-fsdevel@vger.kernel.org, dm-devel@redhat.com, viro@ZenIV.linux.org.uk, linux-ext4@vger.kernel.org, xfs@oss.sgi.com, axboe@kernel.dk, mtk.manpages@googlemail.com, linux-kernel@vger.kernel.org To: Eric Sandeen Return-path: Content-Disposition: inline In-Reply-To: <48E0E7D4.1090409@sandeen.net> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Mon, Sep 29, 2008 at 09:36:04AM -0500, Eric Sandeen wrote: > Christoph Hellwig wrote: > > On Fri, Sep 26, 2008 at 05:52:35PM +0900, Takashi Sato wrote: > >> I think that your concern is that the freezer cannot recognize the occurrence > >> of a timeout and it continues the backup process and the backup data is > >> corrupted finally. > > > > What timeout should happen? the freeze ioctl must not return until the > > filesystem is a clean state and all writes are blocked. > > The suggestion was that *UN*freeze would return ETIMEDOUT if the > filesystem had already unfrozen itself, I think. That way you know that > the snapshot you just took is worthless, at least. But why would the filesystem every unfreeze itself? That defeats the whole point of freezing it.