Add 'blksize' option for block device based filesystems.  During
initialization this is used to set the block size on the device and the super
block.  The default block size is 512bytes.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>