Add an helper to retrieve real data inode associated with overlay inode.
This helper will ignore all metacopy inodes and will return only the real
inode which has data.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Reviewed-by: NAmir Goldstein <amir73il@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>