Re: [PATCH] xfs/030: link .out file according to reflink support status

From: Dave Chinner <david@fromorbit.com>
To: Eryu Guan <eguan@redhat.com>
Cc: fstests@vger.kernel.org, darrick.wong@oracle.com, xfs@oss.sgi.com
Subject: Re: [PATCH] xfs/030: link .out file according to reflink support status
Date: Thu, 31 Mar 2016 15:26:44 +1100	[thread overview]
Message-ID: <20160331042644.GK30721@dastard> (raw)
In-Reply-To: <1459331861-15025-1-git-send-email-eguan@redhat.com>

On Wed, Mar 30, 2016 at 05:57:41PM +0800, Eryu Guan wrote:
> Commit 31f48569c353 ("xfs/030: fix output on newer filesystems") added
> more lines to .out file to match the output from XFS with reflink
> support, but it broke test on older XFS.
> 
> Fix it by introducing new .out file 030.out.reflink.linux to match the
> reflink case, so old XFS still compares .out file against 030.out.linux.
> 
> In order to do this, a new helper is introduced, _fs_has_reflink()
> accepts mount point as argument and returns if the underlying fs
> supports reflink or not.

Let's not go down this path. This is a filtering issue, not a
problem we solve by playing "let's add a golden image file for every
different filesystem format we can create".

The problem here is that reflink triggers a change in the initial
population of the AGFL - from 4 blocks to 6 blocks, and so repair
warns 6 times instead of 4. After filtering, that gives 6 indentical
output lines instead of 4.

Doing something as simple as collapsing repeated identical lines
(e.g filtering through uniq) will work for all filesystem formats
and any future changes that modify the initial AGFL population...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com