From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: I/O topology fixes for big physical block size Date: Mon, 27 Sep 2010 13:23:10 -0400 Message-ID: <20100927172309.GA13874@redhat.com> References: <1285605664-27027-1-git-send-email-martin.petersen@oracle.com> <4CA0CC38.5010804@fusionio.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx1.redhat.com ([209.132.183.28]:30270 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757014Ab0I0RXQ (ORCPT ); Mon, 27 Sep 2010 13:23:16 -0400 Content-Disposition: inline In-Reply-To: <4CA0CC38.5010804@fusionio.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jens Axboe Cc: "Martin K. Petersen" , "James.Bottomley@hansenpartnership.com" , "linux-scsi@vger.kernel.org" On Mon, Sep 27 2010 at 12:54pm -0400, Jens Axboe wrote: > On 2010-09-28 01:41, Martin K. Petersen wrote: > > Mike Snitzer reported that he has access to a device that supports thin > > provisioning but does not use the Block Limits VPD page to indicate > > discard granularity. Instead it reports a huge (1MB) physical block > > size. That caused a bit of fallout in the topology stack which assumed a > > physical block size of 4KiB or less. > > Fixing the overflow aside, I question the validity of setting the physical > block size to something larger than PAGE_SIZE as there's no way that that > could really work in the current kernel. > > I would suggest doing something similar as we do with other 'invalid' > settings that we cannot honor, print a warning and drop the queue > limits to PAGE_SIZE. I'm inclined to agree. Doesn't make a whole lot of sense. But could this cap of PAGE_SIZE be enforced with a follow-on patch? Or would you rather see it be dealt with in a single revised 2/2 patch? Mike