[PATCH] do_mount bug fix

[Wang Yiping]

> > Please provide a simple and complete test case which illustrates the problem.
> >
> > cgf
> >
>  OK, here is the test-case :-)
>
>  mkdir /tmp/test123
>  mount -u -o managed `cygpath -m /home/whateverdd` /tmp/test123/
>  umount /tmp/test123
>
> andy
>
I recheck, umount can delete the entry, with umount -u /tmp/test123.
But  it may be better to check it before it is mounted.