These fields will not be equal only in case if bigalloc filesystem feature is turned on.
This feature is not supported for now.
Reported by: Christopher Krah, Thomas Barabosch, and Jan-Niclas Hilgert of Fraunhofer FKIE
Reported as: FS-27-EXT2-12: Denial of Service in openat-0 (vm_fault_hold/ext2_clusteracct)
MFC after: 2 weeks