On Fri, Jun 20, 2008 at 6:41 PM, Jeff Garzik <jeff@xxxxxxxxxx> wrote: > James Bottomley wrote: >> >> On Fri, 2008-06-20 at 13:06 +0900, Tejun Heo wrote: >>> >>> The biggest problem is how to keep userland happy. hdX -> sdX >>> transition was painful enough and I have a strong feeling that >>> everyone will come after and hunt down us if we try something like sdX >>> -> bdX now. :-) > >> In theory mounting by label or ID should have fixed a lot of this. >> However, if we need to head off a revolt, the sdX allocation algorithm >> can be placed into it's own module so both sd and a ULD ata driver could >> use it ... > >> Actually, surely we can mostly dump the SAT layer? > > > I don't see that we can do that for a long time... And it's not just the > sdX allocation algorithm in question -- SCSI block devices come with their > own partition limits and set of supported ioctls. > > Therefore, my recommended path has always been > > * create ata_disk block device driver (ULD, in your terminology) > > * make SAT an optional piece, which maintains compatibility with existing > SCSI blkdevs, ioctls, command sets > > > I just don't see a valid path moving forward that breaks userland /again/... > we (ATA hackers) would be drummed out of a job I think :) > > Another option that's been discussed is > > 1) Make SCSI block devices themselves an allocate-able resource (I think > that's what you meant by "placed into it's own module so both sd and a ULD > ata driver could use it"?) > > 2) Ensure that any ata_disk ULD would support the same partition limits and > ioctl set, enough to ensure binary compatibility. > > Because that's the real need -- maintaining binary compatibility with SCSI > block devices, so major/minor, ioctl supported set, partition limits, and > other relevant details need to remain unchanged. > 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? FYI: I don't personally use that many partitions, but there is a vocal minority of users on the opensuse mailinglist that complain pretty loudly about current restriction. 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 -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
