From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alasdair G Kergon Subject: Re: [PATCH 1/2] blkdev: fix merge_bvec_fn return value checks Date: Fri, 5 Mar 2010 17:37:16 +0000 Message-ID: <20100305173716.GQ27852@agk-dp.fab.redhat.com> References: <1267292113-12900-1-git-send-email-dmonakhov@openvz.org> <20100228184634.GI5768@kernel.dk> <874okyf4iw.fsf@openvz.org> <170fa0d21003031020x5b71b492vd733cf0d7c9b83d4@mail.gmail.com> <87wrxtkzwu.fsf@openvz.org> <20100303191613.GB18480@redhat.com> <87lje9kx9i.fsf@openvz.org> <20100303200734.GW5768@kernel.dk> <20100304175921.GD3670@soda.linbit> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20100304175921.GD3670@soda.linbit> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids On Thu, Mar 04, 2010 at 06:59:21PM +0100, Lars Ellenberg wrote: > + /* Restricting max_sectors is not enough. > + * If someone uses bio_add_page to add 8 disjunct 512 byte > + * partial pages to a bio, it would succeed, > + * but could still cross a border of whatever restrictions > + * are below us (raid0 stripe boundary). An attempted > + * bio_split would not succeed, because bi_vcnt is 8. > + * E.g. the xen io layer is known to trigger this. > + */ Sounds plausible. Do you or anyone readingt his have example messages demonstrating the failure when this patch is not applied? Alasdair.