[Linux-cluster] How to recover from gnbd "Open Disconnected Pending" state?

[Kirby Zhou]

How to recover from gnbd "Open Disconnected Pending" state?

When the machine which exported gnbd is broken or shutdown, the client
machine would fall into the state 'Open Disconnected Pending'.
Any process accessing the dead gnbd will fall into state 'D'. 
How can I remove the dead gnbd block device on the client machine?

#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