> Log Message:
> specfs changes for PR kern/37717 (raidclose() is no longer called on
> shutdown). There are still problems with device access and a PR will be
> filed.
> 
> - Kill checkalias(). Allow multiple vnodes to reference a single device.
> 
> - Don't play dangerous tricks with block vnodes to ensure that only one
>   vnode can describe a block device. Instead, prohibit concurrent opens of
>   block devices. As a bonus remove the unreliable code that prevents
>   multiple file system mounts on the same device. It's no longer needed.
> 
> - Track opens by vnode and by device. Issue cdev_close() when the last open
>   goes away, instead of abusing vnode::v_usecount to tell if the device is
>   open.

the assertion in spec_strategy is wrong for swapdev_vp
because it is used without VOP_OPEN'ed.

YAMAMOTO Takashi