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

Jeff Darcy jdarcy at redhat.com
Thu Mar 28 15:15:01 UTC 2013

On 03/28/2013 10:07 AM, Theodore Ts'o wrote:
> Any update about whether Gluster can address this without needing the
> ioctl patch?  Or should we push the ioctl patch into ext4 for the next
> merge window?

We have two approaches that don't require the ioctl patch:

* http://review.gluster.org/#change,4675
This takes the approach of mapping between the underlying filesystems'
d_off values and our own, using a cache.  It works for obvious cases,
but it's a really horrible kludge.

* http://review.gluster.org/#change,4711
This is Avati's and Zach's approach, which "rounds off" the ext4 d_off
values to free up some bits that we can use.  There seems to be a
general consensus (among the people who've discussed it on this list)
that the approach is preferable, but it doesn't quite work yet.

Between those two and the possibility of "tune2fs -O ^dir_index" I think
we can keep this from affecting our users, but since they're both a bit
unclean in different ways the ioctl might still be desirable.  I'll let
others who've been more involved with that (e.g. Avati/Zach/Eric) give a
more authoritative answer.

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