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 16:07:30 +0100 Message-ID: <1225292850.1196.4.camel@o> References: <1225285328.3974.5.camel@o> <20081029135607.GF31233@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: <20081029135607.GF31233@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, 13:56 +0000 schrieb Alasdair G Kergon: > On Wed, Oct 29, 2008 at 02:02:08PM +0100, Heinz Mauelshagen wrote: > > This patch adds checks to the dirty log creation for region size to be > > larger than 2 sectors and to be a power of 2. > > Interesting we didn't validate that, but the userspace validation is > tighter. > > if (lp->region_size % (pagesize >> SECTOR_SHIFT)) { > log_error("Region size (%" PRIu32 ") must be a multiple of " > "machine memory page size (%d)", > lp->region_size, pagesize >> SECTOR_SHIFT); > > The validation should be consistent between userspace and kernel. > Alasdair 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). Heinz