app-admin/fam-2.7.0-r2 famd blocks unmounting devices by keeping a reference on modified files (?) at least lsof says famd is the blocking process /etc/init.d/famd restart is a workaround http://forums.gentoo.org/viewtopic-t-252620-highlight-famd+umount.html http://forums.gentoo.org/viewtopic-t-260230-highlight-famd+umount.html
Use gamin. *** This bug has been marked as a duplicate of 75360 ***
This is a known issue with famd. Sun knows about this. (They are the creators and maintainers of famd.) Due to the nature of famd there is no possible solution to this issue. It will remain for good. This is was famd is depreciated in favor of it's newer and better replacement called "gamin".