/usr/share/glusterfs/scripts/gsync-sync-gfid is in glusterfs-common 3.5.2-2+deb8u3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/glusterfs/scripts/../../../lib/glusterfs/gsync-sync-gfid
/usr/share/glusterfs/scripts/../../../lib/glusterfs/gsync-sync-gfid