From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH] scsi: allow persistent reservations without CAP_SYS_RAWIO Date: Tue, 12 Jun 2012 19:25:40 +0200 Message-ID: <4FD77B94.1030207@redhat.com> References: <1339517312-18134-1-git-send-email-pbonzini@redhat.com> <1339518069.3050.8.camel@dabdike.int.hansenpartnership.com> <4FD76D57.5020709@redhat.com> <4FD77438.6090202@redhat.com> <1339521657.3050.13.camel@dabdike.int.hansenpartnership.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1339521657.3050.13.camel@dabdike.int.hansenpartnership.com> Sender: linux-kernel-owner@vger.kernel.org To: James Bottomley Cc: linux-kernel@vger.kernel.org, axboe@kernel.dk, linux-scsi@vger.kernel.org List-Id: linux-scsi@vger.kernel.org Il 12/06/2012 19:20, James Bottomley ha scritto: > I don't think you understand how persistent reservations work. > > The first thing I'll say is I agree with Alan. Unless you can justify > why you want to relax permissions I'm not going to do it. See my answer to John. The reason is that I want to let VMs use persistent reservations without running them as root. > But secondly, the reason we're so up in arms about SCSI-3 PR is that > there's a feature called reservation by transport ID. This is used to > reserve multipath devices when one of the paths is down. Effectively it > allows a PR-OUT command to set a reservation on any LUN with access only > to one of them. It's definitely a hack in the SCSI standard, but it's > not one that can be controlled by a unix like permission model. Write > access to *any* LUN allows you to reserve *all* luns. Thanks for taking the time to explain---I knew about this, but I thought it could (perhaps should) be disabled on the SAN. Anybody could already use reservation by transport ID if they had root access on the local machine, no? Paolo