From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Durgin Subject: Re: Modifying RBD image changes it's snapshot Date: Wed, 26 Jun 2013 11:15:34 -0700 Message-ID: <51CB2FC6.6070803@inktank.com> References: <1805042.yIbHV06QAO@karol-esprimo-p5925> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pd0-f175.google.com ([209.85.192.175]:35374 "EHLO mail-pd0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751383Ab3FZSQP (ORCPT ); Wed, 26 Jun 2013 14:16:15 -0400 Received: by mail-pd0-f175.google.com with SMTP id 4so1600564pdd.34 for ; Wed, 26 Jun 2013 11:16:15 -0700 (PDT) In-Reply-To: <1805042.yIbHV06QAO@karol-esprimo-p5925> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Karol Jurak Cc: ceph-devel@vger.kernel.org On 06/26/2013 05:40 AM, Karol Jurak wrote: > Hi, > > I'm using ceph 0.56.6 and kernel 3.9.7 and it looks like modifying RBD image > also changes it's snapshot. I can reproduce this as follows: > > # create and map an image > rbd create --size 128 test-1 > rbd map test-1 > > # write some data to the image > dd if=/dev/zero of=/dev/rbd/rbd/test-1 bs=1M count=128 > > # create and map a snapshot > rbd snap create test-1@snap-1 > rbd map test-1@snap-1 > > # verify that image and snapshot are identical > md5sum /dev/rbd/rbd/test-1 /dev/rbd/rbd/test-1@snap-1 > fde9e0818281836e4fc0edfede2b8762 /dev/rbd/rbd/test-1 > fde9e0818281836e4fc0edfede2b8762 /dev/rbd/rbd/test-1@snap-1 > > # modify the image > dd if=/dev/urandom of=/dev/rbd/rbd/test-1 bs=512 count=1 > > # compare checksums again > md5sum /dev/rbd/rbd/test-1 /dev/rbd/rbd/test-1@snap-1 > 1d942c8a5bc7480cecb945ea0d020eed /dev/rbd/rbd/test-1 > 1d942c8a5bc7480cecb945ea0d020eed /dev/rbd/rbd/test-1@snap-1 > > Checksums are identical although the snapshot isn't supposed to be modified. > Just reproduced on 3.10-rc7 as well. It seems the snapshot context loading is broken for format 1 a t least, since unmapping and mapping after the snapshot exists still has the same problem. I added http://tracker.ceph.com/issues/5464 to track this. Apparently the regression test for this hasn't been running, or we would've caught this sooner. Josh