*Do not allow to knockback target which is much larger than caster.

--HG--
branch : trunk

src/game/SpellEffects.cpp

@@ -6376,6 +6376,14 @@ void Spell::EffectKnockBack(uint32 i)
             return;
     }
 
+    float ratio = m_caster->GetCombatReach() / unitTarget->GetCombatReach();
+    ratio = ratio * ratio * ratio; // volume = length^3
+    ratio *= 0.1f; // dbc value
+    float speedxy = float(m_spellInfo->EffectMiscValue[i]) * ratio;
+    float speedz = float(damage) * ratio;
+    if(speedxy < 0.1f && speedz < 0.1f)
+        return;
+
     float x, y;
     if(m_targets.m_targetMask & TARGET_FLAG_DEST_LOCATION)
     {
@@ -6388,9 +6396,6 @@ void Spell::EffectKnockBack(uint32 i)
         y = m_caster->GetPositionY();
     }
 
-    float speedxy = float(m_spellInfo->EffectMiscValue[i])/10;
-    float speedz = float(damage/10);
-
     unitTarget->KnockbackFrom(x, y, speedxy, speedz);
 }