However the original bug fix took care only of VDIs created from raw images in Glance/Objectstore.
The code for VHD download was added concurrently with this fix, and therefore currently lacks 'protection' against instance build failure. Therefore, if the bug has been observed while building instance from VHDs that would explain it. Otherwise it's a regression.
This could be a regression of bug #694935
However the original bug fix took care only of VDIs created from raw images in Glance/Objectstore.
The code for VHD download was added concurrently with this fix, and therefore currently lacks 'protection' against instance build failure. Therefore, if the bug has been observed while building instance from VHDs that would explain it. Otherwise it's a regression.