From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heinz Mauelshagen Subject: Re: [PATCH] Check region size during dirty log creation Date: Wed, 29 Oct 2008 16:53:42 +0100 Message-ID: <1225295622.1196.12.camel@o> References: <1225285328.3974.5.camel@o> <20081029135607.GF31233@agk.fab.redhat.com> <1225292850.1196.4.camel@o> <20081029154357.GI31233@agk.fab.redhat.com> Reply-To: heinzm@redhat.com, device-mapper development Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20081029154357.GI31233@agk.fab.redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Alasdair G Kergon Cc: device-mapper development List-Id: dm-devel.ids Am Mittwoch, den 29.10.2008, 15:43 +0000 schrieb Alasdair G Kergon: > On Wed, Oct 29, 2008 at 04:07:30PM +0100, Heinz Mauelshagen wrote: > > Am Mittwoch, den 29.10.2008, 13:56 +0000 schrieb Alasdair G Kergon: > > > On Wed, Oct 29, 2008 at 02:02:08PM +0100, Heinz Mauelshagen wrote: > > > The validation should be consistent between userspace and kernel. > > It should be sufficiently restrictive in the kernel to prevent > > programming errors causing oopses. It can be called via the kernel > > interface by any application anyway, so doesn't need to enforce our > > uspace restrictions (think direct IOCTL calls). > > Surely the validation in the two places should match? I'm arguing, that the kernel should only restrict to prevent against programming errors. > Why would userspace need a tighter restriction than the kernel? Because of specific application requirements. Why shouldn't we support 2 sector dirty log region sizes for any application who wants them ? > One or the other is incorrect. > - E.g. Does kcopyd handle sub-page regions OK now? kcopyd allows copying io regions of single sectors. Heinz > > Alasdair