From: Anand Avati <anand.avati-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: regressions due to 64-bit ext4 directory cookies
Date: Wed, 13 Feb 2013 16:05:01 -0800
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Cc: Bernd Schubert <bernd.schubert-mPn0NPGs4xGatNDF+KUbs4QuADTiUCJX@public.gmane.org>,
	linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, sandeen-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, gluster-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org
To: "Theodore Ts'o" <tytso-3s7WtUTddSA@public.gmane.org>
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On Wed, Feb 13, 2013 at 3:44 PM, Theodore Ts'o <tytso-3s7WtUTddSA@public.gmane.org> wrote:
>
> I suspect this would seriously screw over Gluster, though, and this
> wouldn't be a solution for NFSv3, since NFS needs long-lived directory
> cookies, and not the short-lived cookies which is all POSIX/SuSv3
> guarantees.
>

Actually this would work just fine with Gluster. Except in the case of
gluster-NFS, the native client is only acting like a router/proxy of
syscalls to the backend system. A directory opened by an application will
have a matching directory fd opened on ext4, and readdir from an app will
be translated into readdir on the matching fd on ext4. So the
app-on-glusterfs and glusterfsd-on-ext4 are essentially "moving in tandem".
As long as the offs^H^H^H^H cookies do not overflow in the transformation,
Gluster would not have a problem.

However Gluster-NFS (and NFS in general, too) will break, as we
opendir/closedir potentially on every request.

Avati

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<br><div class=3D"gmail_quote">On Wed, Feb 13, 2013 at 3:44 PM, Theodore Ts=
&#39;o <span dir=3D"ltr">&lt;<a href=3D"mailto:tytso-3s7WtUTddSA@public.gmane.org" target=3D"_bl=
ank">tytso-3s7WtUTddSA@public.gmane.org</a>&gt;</span> wrote:<blockquote class=3D"gmail_quote" s=
tyle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

I suspect this would seriously screw over Gluster, though, and this<br>
wouldn&#39;t be a solution for NFSv3, since NFS needs long-lived directory<=
br>
cookies, and not the short-lived cookies which is all POSIX/SuSv3 guarantee=
s.<br></blockquote><div>=A0</div><div><div>Actually this would work just fi=
ne with Gluster. Except in the case of gluster-NFS, the native client is on=
ly acting like a router/proxy of syscalls to the backend system. A director=
y opened by an application will have a matching directory fd opened on ext4=
, and readdir from an app will be translated into readdir on the matching f=
d on ext4. So the app-on-glusterfs and glusterfsd-on-ext4 are essentially &=
quot;moving in tandem&quot;. As long as the offs^H^H^H^H cookies do not ove=
rflow in the transformation, Gluster would not have a problem.</div>
<div><br></div><div>However Gluster-NFS (and NFS in general, too) will brea=
k, as we opendir/closedir potentially on every request.</div></div><div><br=
></div><div>Avati</div></div>

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