From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Durgin Subject: Re: [PATCH 08/16] rbd: don't store pool name in struct rbd_dev Date: Wed, 11 Jul 2012 16:32:59 -0700 Message-ID: <4FFE0D2B.6030400@inktank.com> References: <4FFD847C.7070205@inktank.com> <4FFD875B.3060608@inktank.com> <4FFDD5B9.9090101@inktank.com> <4FFDFD59.8000105@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-yx0-f174.google.com ([209.85.213.174]:44995 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933422Ab2GKXdB (ORCPT ); Wed, 11 Jul 2012 19:33:01 -0400 Received: by yenl2 with SMTP id l2so1846269yen.19 for ; Wed, 11 Jul 2012 16:33:01 -0700 (PDT) In-Reply-To: <4FFDFD59.8000105@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Alex Elder Cc: ceph-devel@vger.kernel.org On 07/11/2012 03:25 PM, Alex Elder wrote: > On 07/11/2012 02:36 PM, Josh Durgin wrote: >> On 07/11/2012 07:02 AM, Alex Elder wrote: >>> An rbd device's pool name is used to specify the pool to use for an >>> rbd image when it gets mapped (via rbd_add()). However, only the >>> pool id can be relied on to be invariant--the name of a pool can >>> change at any time. >>> >>> This means that the name of the pool is potentially stale as soon as >>> the image is mapped, so it's a bad idea to record this information. >>> So only store the pool id, not its name, in an rbd_dev. >>> >>> Here are a few specific notes about this change: >>> - The "pool" name device attribute (/sys/bus/rbd/devices//pool) >>> goes away. In its place is a "pool_id" attribute that provide >>> the numeric pool id for the rbd image. >> >> We're using the pool name for udev to provide a predictable device name >> (/dev/rbd/poolname/imagename[@snapname]), so we probably want to keep >> the sysfs attribute. I don't think there's a good way for us to detect >> pool renames right now though, so we should document that the pool >> name reported does not reflect any potential renames. > > OK. I'll put the "pool" name entry back, but will still include the > new "pool_id" entry as well. Do you want me to re-post after that, > or can I consider this reviewed? Consider it reviewed. The same goes for the rest of this series, since it was just minor changes.