@Override
  public void setUpdateInProgress(final boolean underUpdate) {
    if (underUpdate) {
      setBits(UPDATE_IN_PROGRESS);
    } else {
      clearBits(~UPDATE_IN_PROGRESS);
    }
  }
Any bits in "bitMask" that are 0 will be cleared.
geode-core/src/main/java/org/apache/geode/internal/cache/entries/AbstractRegionEntry.java