From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ipmail06.adl2.internode.on.net ([150.101.137.129]:29070 "EHLO ipmail06.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750775AbaBGEl5 (ORCPT ); Thu, 6 Feb 2014 23:41:57 -0500 Date: Fri, 7 Feb 2014 15:41:53 +1100 From: Dave Chinner To: Wang Shilong Cc: xfs@oss.sgi.com, linux-btrfs@vger.kernel.org, jbacik@fb.com Subject: Re: [PATCH v3] Btrfs: add regression test for running snapshot and send concurrently Message-ID: <20140207044153.GF13647@dastard> References: <1391703008-2322-1-git-send-email-wangshilong1991@gmail.com> <20140206224337.GB13647@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Fri, Feb 07, 2014 at 12:18:31PM +0800, Wang Shilong wrote: > > Hi Dave, > > > On Fri, Feb 07, 2014 at 12:10:08AM +0800, Wang Shilong wrote: > >> +$BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT \ > >> + $SCRATCH_MNT/snap_1 >> $seqres.full 2>&1 > >> + > >> +do_snapshots & > >> +snapshots_pid=$! > >> + > >> +$BTRFS_UTIL_PROG send $SCRATCH_MNT/snap_1 > /dev/null 2>&1 || echo "btrfs send failed" > > > > Let's stop this anti-pattern before it takes hold. > > > > If there's output from the send command it should be > > filtered and captured in the golden image. Hence any deviation > > caused by errors is automatically flagged as an error. > > > > That's the whole point of using golden images for capturing errors - > > you don't need to capture return values from binaries and it > > guarantees that users are informed about failures through error > > messages. IOWs: > > > > $BTRFS_UTIL_PROG send $SCRATCH_MNT/snap_1 | _btrfs_send_filter > > > > is what you should be doing here. > > I knew what you mean here, in fact, i did this on purpose. Ok, then you need to explain why you did it on purpose with a comment. It's just as important to explain the reason for doing something in test code as it is in the kernel code. i.e. so when we are looking at the test in 5 years time we know the reason for it being that way. > for this test failure, btrfs-prog did not output failure > information from the beginning. I have nothing good to say about that state of affairs, but... > So to make older progs can also > detect the test failure, i dropped into this way. .. it's going to have to stay like it. Please insert an appropriately sarcastic comment about the usefulness of a silent send command here, because if I write it I'm going to offend lots of people. :/ Cheers, Dave. -- Dave Chinner david@fromorbit.com