Test that an incremental send operation works when in both snapshots
there are two directory inodes that have the same number but
different generations and have an entry with the same name that
corresponds to different inodes in each snapshot.
The btrfs issue is fixed by the following patch for the linux kernel:
"Btrfs: incremental send, do not issue invalid rmdir operations"
Signed-off-by: Robbie Ko <robbieko@synology.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Eryu Guan <eguan@redhat.com>