From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Thin device provisioning Date: Fri, 8 Aug 2008 07:15:11 -0600 Message-ID: <20080808131511.GC8618@parisc-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from palinux.external.hp.com ([192.25.206.14]:54448 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751019AbYHHNPb (ORCPT ); Fri, 8 Aug 2008 09:15:31 -0400 Content-Disposition: inline Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: knight@netapp.com Cc: David Woodhouse , ricwheeler@gmail.com, linux-scsi@vger.kernel.org, t10@t10.org Good morning Fred, I've been looking at your 08-149r0.pdf with a view to using the 'PUNCH' command to implement the Linux 'DISCARD' command. It's a little over-specified for what we need and this causes the implementation to be a little more complex than I would like. The excess capability is the ability to do multiple punches in a single command. Do you really need to be able to add/remove lots of ranges atomically, or could you use a command specified like this: 0 0x9F 1 service action 2-9 LBA 10-13 length 14 reserved 15 control and send one command for each range? Apologies if this has already been covered in a T10 discussion; I'm not a member and though I've searched the archives, I may have missed a discussion. -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."