I've installed FC5 on my asus a6va with default options, so FC5 took all HD space.
Now I want to install Windows, so I try to reduce lvm partition.
I boot from dvd into rescue mode, accepted to mount sysimage in RW mode, then follow steps from this
# umount /mnt/sysimage/sys
# umount /mnt/sysimage/dev
# umount /mnt/sysimage/proc
# umount /mnt/sysimage/boot
# umount /mnt/sysimage <--- here I get umount: /mnt/sysimage: Device or resource busy