Use the vmkfstools command to break the device lock on a particular partition.

-B|--breaklock device

When entering the device parameter, use the following format:

/vmfs/devices/disks/disk_ID:P

You can use this command when a host fails in the middle of a datastore operation, such as expand the datastore, add an extent, or resignature. When you run this command, make sure that no other host is holding the lock.