diff --git a/cinder/tests/unit/volume/drivers/netapp/dataontap/client/test_client_cmode.py b/cinder/tests/unit/volume/drivers/netapp/dataontap/client/test_client_cmode.py
index 60e4c2cf745..2b75a7653bf 100644
--- a/cinder/tests/unit/volume/drivers/netapp/dataontap/client/test_client_cmode.py
+++ b/cinder/tests/unit/volume/drivers/netapp/dataontap/client/test_client_cmode.py
@@ -733,9 +733,9 @@ class NetAppCmodeClientTestCase(test.TestCase):
     def test_clone_lun_multiple_zapi_calls(self):
         """Test for when lun clone requires more than one zapi call."""
 
-        # Max block-ranges per call = 32, max blocks per range = 2^24
+        # Max clone size per call = 2^18 blocks * 512 bytes/block = 128 MB
         # Force 2 calls
-        bc = 2 ** 24 * 32 * 2
+        bc = 2 ** 18 * 2
         self.client.clone_lun('volume', 'fakeLUN', 'newFakeLUN',
                               block_count=bc)
         self.assertEqual(2, self.connection.invoke_successfully.call_count)
diff --git a/cinder/volume/drivers/netapp/dataontap/client/client_cmode.py b/cinder/volume/drivers/netapp/dataontap/client/client_cmode.py
index 825f69bbd05..5829159b4bc 100644
--- a/cinder/volume/drivers/netapp/dataontap/client/client_cmode.py
+++ b/cinder/volume/drivers/netapp/dataontap/client/client_cmode.py
@@ -452,19 +452,16 @@ class Client(client_base.Client):
     def clone_lun(self, volume, name, new_name, space_reserved='true',
                   qos_policy_group_name=None, src_block=0, dest_block=0,
                   block_count=0, source_snapshot=None, is_snapshot=False):
-        # zAPI can only handle 2^24 blocks per range
-        bc_limit = 2 ** 24  # 8GB
-        # zAPI can only handle 32 block ranges per call
-        br_limit = 32
-        z_limit = br_limit * bc_limit  # 256 GB
-        z_calls = int(math.ceil(block_count / float(z_limit)))
+        # ONTAP handles only 128 MB per call as of v9.1
+        bc_limit = 2 ** 18  # 2^18 blocks * 512 bytes/block = 128 MB
+        z_calls = int(math.ceil(block_count / float(bc_limit)))
         zbc = block_count
         if z_calls == 0:
             z_calls = 1
         for _call in range(0, z_calls):
-            if zbc > z_limit:
-                block_count = z_limit
-                zbc -= z_limit
+            if zbc > bc_limit:
+                block_count = bc_limit
+                zbc -= bc_limit
             else:
                 block_count = zbc
 
diff --git a/releasenotes/notes/bug-1762424-f76af2f37fe408f1.yaml b/releasenotes/notes/bug-1762424-f76af2f37fe408f1.yaml
new file mode 100644
index 00000000000..90c08f0ed35
--- /dev/null
+++ b/releasenotes/notes/bug-1762424-f76af2f37fe408f1.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    NetApp ONTAP (bug 1762424): Fix ONTAP NetApp driver not being able to extend
+    a volume to a size greater than the corresponding LUN max geometry.