From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Greg Freemyer" Subject: Re: [RFC] Separating out libata out of SCSI (finally) Date: Tue, 24 Jun 2008 10:58:36 -0400 Message-ID: <87f94c370806240758i2013804cob120daffc94c5ae2@mail.gmail.com> References: <485B2CC6.6070201@kernel.org> <1213993737.3443.35.camel@localhost.localdomain> <485C31FE.8050408@garzik.org> <87f94c370806231404t13586777x7f7bee24ebe25ffc@mail.gmail.com> <1214255460.3310.27.camel@localhost.localdomain> <4860B099.2030305@panasas.com> <1214318550.3299.7.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1214318550.3299.7.camel@localhost.localdomain> Content-Disposition: inline Sender: linux-ide-owner@vger.kernel.org To: James Bottomley Cc: Boaz Harrosh , Jeff Garzik , Tejun Heo , IDE/ATA development list , linux-scsi , brking@linux.vnet.ibm.com, Mark Lord , Alan Cox , Jens Axboe List-Id: linux-scsi@vger.kernel.org On Tue, Jun 24, 2008 at 10:42 AM, James Bottomley wrote: > On Tue, 2008-06-24 at 11:30 +0300, Boaz Harrosh wrote: >> James Bottomley wrote: >> > On Mon, 2008-06-23 at 17:04 -0400, Greg Freemyer wrote: >> >> I've seen a lot of end user complaints about libata only supporting >> >> 15(14?) partitions. Will that limit be moved back to the traditional >> >> drivers/ide limit as part of this? >> > >> > Number of partitions is directly related to number of minors, so it >> > can't be changed without a change in the allocation of major/minor space >> > in sd ... that could only be done compatibly by permuting the space. >> > The only other way to do it is incompatibly by changing major (again). >> > >> Could we do both? I mean use the legacy, up to 15, with the old major, >> then use the new major for bigger then 15. Since user mode that knows >> about more then 15 partitions is new, it'll know it needs to jump a major. > > Not simultaneously, which is the problem; you can't have two separate > block devices for the same physical device unless you want aliasing > issues in the page cache. > > It might be possible to add an extra device to give access to the > missing partitions, but that would require a bit of re-engineering in > gendisk (which is the in-kernel code to manage the partitions). > > What might be far more feasible is to set up udev to use kpartx to > provide the missing partitions if it detects a partition table that has > them ... of course, that requires a udev setup and most of the > complaints about the lost partitions seem to come from non-udev systems. > > But .... if everyone (particularly the people with these problems) had > udev, we could simply migrate to a new major with more partitions, get > udev to fix it all up for us and everyone would be happy because no-one > would even notice that we'd moved majors ... > > James >>From my limited perspective, every complaint I've seen was related to OpenSUSE which I believe is a udev based distro, so addressing this for the udev based distros would address that contingent of users. Greg -- Greg Freemyer Litigation Triage Solutions Specialist http://www.linkedin.com/in/gregfreemyer First 99 Days Litigation White Paper - http://www.norcrossgroup.com/forms/whitepapers/99%20Days%20whitepaper.pdf The Norcross Group The Intersection of Evidence & Technology http://www.norcrossgroup.com