There is a race condition when a VDI is mounted and the device node is created. Sometimes (depending on the configuration of the Linux distribution) nova loses the race and will try to open the block device before it has been created in /dev.
There is a race condition when a VDI is mounted and the device node is created. Sometimes (depending on the configuration of the Linux distribution) nova loses the race and will try to open the block device before it has been created in /dev.

This change will poll waiting on the device node to be created before attempting to use it.
n0ano/ganttclient