I've seen some of theese already. The bug is actually not in
libvirt but
in gluster's libgfapi library, so any change in libvirt won't help.
This was tracked in gluster as:
https://bugzilla.redhat.com/show_bug.cgi?id=1093594
I suggest you update the gluster library to resolve this issue.
Peter, Michal - thank You for Your time. I'll try higher gluster version.
Best regards
Piotr Rybicki