While writing a version of losetup, I ran into the problem that the loop
device was returning total garbage.

It turns out the problem was that this losetup was only issuing the
LOOP_SET_FD ioctl and not issuing a subsequent LOOP_SET_STATUS ioctl.  This
losetup didn't have any special status to set, so it left out the call.

The deeper cause is that loop_set_fd sets the transfer function to NULL,
which causes no transfer to happen lo_do_transfer.

This patch fixes the problem by setting transfer to transfer_none in
loop_set_fd.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>