Why can't I flush /dev/ram0?

[Kelledin Tane]

At this point, I'm trying to get an initrd working properly.  So far, it
works, the system boots, etc. etc., but whenever I try to do a "blockdev
--flushbufs /dev/ram0", I get "device or resource busy"

When I mount the filesystem to check it out, nothing appears to have
anything open on the filesystem.  So why am I not able to flush it
clean?

This is kernel 2.4.5 stock, btw.

Kelledin