From: Anand Avati Subject: Re: regressions due to 64-bit ext4 directory cookies Date: Wed, 13 Feb 2013 16:05:01 -0800 Message-ID: References: <20130213151455.GB17431@thunk.org> <20130213151953.GJ14195@fieldses.org> <20130213153654.GC17431@thunk.org> <20130213162059.GL14195@fieldses.org> <20130213222052.GD5938@thunk.org> <20130213224141.GU14195@fieldses.org> <20130213224720.GE5938@thunk.org> <20130213230511.GW14195@fieldses.org> <20130213234430.GF5938@thunk.org> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============5388674227217865952==" Cc: Bernd Schubert , 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" Return-path: In-Reply-To: <20130213234430.GF5938-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gluster-devel-bounces+gcfgd-gluster-devel=m.gmane.org-qX2TKyscuCcdnm+yROfE0A@public.gmane.org Sender: gluster-devel-bounces+gcfgd-gluster-devel=m.gmane.org-qX2TKyscuCcdnm+yROfE0A@public.gmane.org List-Id: linux-ext4.vger.kernel.org --===============5388674227217865952== Content-Type: multipart/alternative; boundary=f46d0444edd393dc5f04d5a40293 --f46d0444edd393dc5f04d5a40293 Content-Type: text/plain; charset=ISO-8859-1 On Wed, Feb 13, 2013 at 3:44 PM, Theodore Ts'o 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 --f46d0444edd393dc5f04d5a40293 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
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<= br> cookies, and not the short-lived cookies which is all POSIX/SuSv3 guarantee= s.
=A0
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". As long as the offs^H^H^H^H cookies do not ove= rflow in the transformation, Gluster would not have a problem.

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