da309e8c055d ("ovl: factor out ovl_map_dev_ino() helper")
9f99e50d460a ("ovl: set lower layer st_dev only if setting lower st_ino")
86eaa13046d5 ("ovl: unbless lower st_ino of unverified origin")
a0c5ad307ac0 ("ovl: relax same fs constraint for constant st_ino")
ba1e563cdc6b ("ovl: return anonymous st_dev for lower inodes")