[Linux-cluster] How to resolve "Open Disconnected Pending" state?

[Kirby Zhou]

The machine which exported gnbd is power off. The client machine fall into
the state 'Open Disconnected Pending'.
Any process access the dead gnbd fall into state 'D'. 
How can I destroy the gnbd block device on the client machine?

[root at xen-727057 ~]# gnbd_import -n -l
Device name : 63.131.xvdb
----------------------
    Minor # : 0
 sysfs name : /block/gnbd0
     Server : 10.10.63.131
       Port : 14567
      State : Open Disconnected Pending
   Readonly : No
    Sectors : 16777216

[root at xen-727057 ~]# pvs &
[1] 4561
[root at xen-727057 ~]# ps aux | fgrep pvs
root      4561  0.6  0.1  79364  1544 pts/0    D    14:50   0:00 pvs
root      4563  0.0  0.0  61112   608 pts/0    S+   14:50   0:00 fgrep pvs

[root at xen-727057 ~]# gnbd_import -n -R
gnbd_import: ERROR cannot disconnect device #0 : Device or resource busy