mkfs.ext2 in cygwin not working

Question

I'm attempting to create a fs within a file.

under linux it's very simple:

create a blank file size 8 gb

dd of=fsFile bs=1 count=0 seek=8G

"format" the drive:

mkfs.ext2 fsFile works great.

however under cygwin running from /usr/sbin ./mkfs.ext2 has all kinds of weird errors (i assume because of some abstraction)

But with cygwin i get:

mkfs.ext2: Device size reported to be zero. Invalid partition specified, or partition table wasn't reread after running fdisk, due to a modified partition being busy and in use. You may need to reboot to re-read your partition table.

or even worse (if i try to access a file through /cygdrive/...

mkfs.ext2: Bad file descriptor while trying to determine filesystem size

:( please help, Thanks