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Date:   Wed, 26 Jul 2023 09:28:23 -0700
From:   Luis Chamberlain <mcgrof@kernel.org>
To:     Theodore Ts'o <tytso@mit.edu>
Cc:     "Darrick J. Wong" <djwong@kernel.org>,
        Zorro Lang <zlang@redhat.com>, fstests@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, patches@lists.linux.dev
Subject: Re: [PATCH] fstests: add helper to canonicalize devices used to
 enable persistent disks
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On Wed, Jul 26, 2023 at 12:41:32AM -0400, Theodore Ts'o wrote:
> On Tue, Jul 25, 2023 at 08:54:39AM -0700, Darrick J. Wong wrote:
> > On Tue, Jul 25, 2023 at 04:13:07PM +0800, Zorro Lang wrote:
> > > On Wed, Jul 19, 2023 at 11:17:27PM -0700, Luis Chamberlain wrote:
> > > > The filesystem configuration file does not allow you to use symlinks to
> > > > devices given the existing sanity checks verify that the target end
> > > > device matches the source.
> 
> I'm a little confused.  Where are these "sanity checks" enforced?
> I've been using
> 
> SCRATCH_DEV=/dev/mapper/xt-vdc
> 
> where /dev/mapper/xt-vdc is a symlink to /dev/dm-4 (or some such)
> without any problems.  So I don't quite understand why we need to
> canonicalize devices?

That might work, but try using /dev/disk/by-id/ stuff, that'll bust. So
to keep existing expecations by fstests, it's needed.

  Luis