From mboxrd@z Thu Jan  1 00:00:00 1970
From: Amir Goldstein <amir73il@gmail.com>
Subject: Re: [PATCH v2 05/11] ovl: lookup redirect by file handle
Date: Fri, 28 Apr 2017 12:57:48 +0300
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To: Miklos Szeredi <miklos@szeredi.hu>
Cc: "linux-unionfs@vger.kernel.org" <linux-unionfs@vger.kernel.org>, Vivek Goyal <vgoyal@redhat.com>

On Fri, Apr 28, 2017 at 12:37 PM, Miklos Szeredi <miklos@szeredi.hu> wrote:
> On Fri, Apr 28, 2017 at 10:15 AM, Amir Goldstein <amir73il@gmail.com> wrote:
>
>> Well, we could add configuration options to decide if and how to follow
>> and verify fh for non-dir, but:
>>
>> 1. We agreed that trying to follow fh for non-dir is a no-loose situation
>>     for !redirect and hot cache case and a probable win for redirect with
>>     cold case
>
> Okay.  That also means that redirect is not actually needed for
> non-dir.  Well, except for the weird case of having to reconstruct a
> reverse mapping after copying the layers in order to properly handle
> copy up of hardlinks on the lower layer.  But lets not care about that
> for now (or ever, probably).
>

It's needed for when we can't lookup by fh:
- lower has NULL uuid
- !same_lower_sb (may be relaxed going forward)

Heh, it's hard too keep track of it all ;-)

Once all the dust is settled, I'll sit down to write a 'Redirect by file handle'
section for  Documentation/filesystems/overlayfs.txt that will summarize
all cases.

Amir.