func EnsureMaxPermissions(fi os.FileInfo, maxPerms os.FileMode) error
EnsureMaxPermissions tests the provided file info, returning an error if the file's permission bits contain excess permissions not set in maxPerms.
For example, a file with permissions -rw------- will successfully validate with maxPerms -rw-r--r-- or -rw-rw-r--, but will not validate with maxPerms -r-------- (due to excess --w------- permission) or --w------- (due to excess -r-------- permission).
Only permission bits of the file modes are considered.
func IsMetaFile(e os.DirEntry) (bool, error)
IsMetaFile tests wheter a DirEntry appears to be a metadata file or not.