From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:16863 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751558AbaDORVq (ORCPT ); Tue, 15 Apr 2014 13:21:46 -0400 Message-ID: <534D6AAA.4010709@fb.com> Date: Tue, 15 Apr 2014 13:21:46 -0400 From: Chris Mason MIME-Version: 1.0 To: , , Miao Xie , Wang Shilong Subject: Re: [PATCH 1/2] btrfs: protect snapshots from deleting during send References: <6c15e8cf5f832398461e8dbde0a02255c35fdd4b.1397572052.git.dsterba@suse.cz> <534D479E.3070200@fb.com> <20140415154412.GU29256@twin.jikos.cz> <534D57B1.6090501@fb.com> <20140415162734.GX29256@suse.cz> In-Reply-To: <20140415162734.GX29256@suse.cz> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 04/15/2014 12:27 PM, David Sterba wrote: > On Tue, Apr 15, 2014 at 12:00:49PM -0400, Chris Mason wrote: >>>> I'm worried about the use case where we have: >>>> >>>> * periodic automated snapshots >>>> * periodic automated deletion of old snapshots >>>> * periodic send for backup >>>> >>>> The automated deletion doesn't want to error out if send is in progress, it >>>> just wants the deletion to happen in the background. >>> >>> I'd give the precedence to the 'backup' process before the 'clean old >>> snapshots', because it can do more harm if the snapshot is removed >>> meanwhile without any possibility to recover. >> >> Right, we don't want either process to stop with an error. We just want >> them to continue happily and do the right thing... > > ... if everything goes without errors. Not like send going out of > memory, send through network has a glitch, send to a file runs out of > space, and has to be restarted. Is this too unrealistic to happen? > It's a good point, a better way to say what I have in mind is that we shouldn't be adding new transient errors to the send process (on purpose ;) -chris