file-backed cgd backup question

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

For a cgd in a file that I mount via vnd+cgd, the file system contents
inside may change, but the actual file on the hard disk outside only
has 'access' time changes. So "smart" backup programs that check
timestamps to find out if they need to re-hash files don't notice it
was changed. How do you handle this? Manually touch it?

Cheers,
 Thomas