[Gluster-devel] regressions due to 64-bit ext4 directory cookies

Anand Avati anand.avati at gmail.com
Thu Mar 28 22:14:50 UTC 2013

On Thu, Mar 28, 2013 at 12:43 PM, Jeff Darcy <jdarcy at redhat.com> wrote:

> On 03/28/2013 02:49 PM, Anand Avati wrote:
> > Yes, it should, based on the theory of how ext4 was generating the
> > 63bits. But Jeff's test finds that the experiment is not matching the
> > theory.
> FWIW, I was able to re-run my test in between stuff related to That
> Other Problem.  What seems to be happening is that we read correctly
> until just after d_off 0x4000000000000000, then we suddenly wrap around
> - not to the very first d_off we saw, but to a pretty early one (e.g.
> 0x0041b6340689a32e).  This is all on a single brick, BTW, so it's pretty
> easy to line up the back-end and front-end d_off values which match
> perfectly up to this point.
> I haven't had a chance to ponder what this all means and debug it
> further.  Hopefully I'll be able to do so soon, but I figured I'd
> mention it in case something about those numbers rang a bell.

Of course, the unit tests (with artificial offsets) were done with brick
count >= 2. You have tested with DHT subvol count=1, which was not tested,
and sure enough, the code isn't handling it well. Just verified with the
unit tests that brick count = 1 condition fails to return the same d_off.

Posting a fixed version. Thanks for the catch!

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