diff --git a/csi/src/controllerserver.go b/csi/src/controllerserver.go
index b9ffba00..50778f08 100644
--- a/csi/src/controllerserver.go
+++ b/csi/src/controllerserver.go
@@ -334,6 +334,7 @@ func (cs *ControllerServer) ControllerGetCapabilities(ctx context.Context, req *
     for _, capability := range []csi.ControllerServiceCapability_RPC_Type{
         csi.ControllerServiceCapability_RPC_CREATE_DELETE_VOLUME,
         csi.ControllerServiceCapability_RPC_LIST_VOLUMES,
+        csi.ControllerServiceCapability_RPC_EXPAND_VOLUME,
         csi.ControllerServiceCapability_RPC_CREATE_DELETE_SNAPSHOT,
         csi.ControllerServiceCapability_RPC_LIST_SNAPSHOTS,
         // TODO: csi.ControllerServiceCapability_RPC_CLONE_VOLUME,
@@ -507,10 +508,58 @@ func (cs *ControllerServer) ListSnapshots(ctx context.Context, req *csi.ListSnap
     return resp, nil
 }
 
-// ControllerExpandVolume resizes a volume
+// ControllerExpandVolume increases the size of a volume
 func (cs *ControllerServer) ControllerExpandVolume(ctx context.Context, req *csi.ControllerExpandVolumeRequest) (*csi.ControllerExpandVolumeResponse, error)
 {
-    return nil, status.Error(codes.Unimplemented, "")
+    klog.Infof("received controller expand volume request %+v", protosanitizer.StripSecrets(req))
+    if (req == nil)
+    {
+        return nil, status.Error(codes.InvalidArgument, "request cannot be empty")
+    }
+    if (req.VolumeId == "" || req.CapacityRange == nil || req.CapacityRange.RequiredBytes == 0)
+    {
+        return nil, status.Error(codes.InvalidArgument, "VolumeId, CapacityRange and RequiredBytes are required fields")
+    }
+
+    volVars := make(map[string]string)
+    err := json.Unmarshal([]byte(req.VolumeId), &volVars)
+    if (err != nil)
+    {
+        return nil, status.Error(codes.Internal, "volume ID not in JSON format")
+    }
+    volName := volVars["name"]
+    ctxVars, _, _ := GetConnectionParams(volVars)
+
+    inodeCfg, err := invokeList(ctxVars, volName, true)
+    if (err != nil)
+    {
+        return nil, err
+    }
+
+    if (req.CapacityRange.RequiredBytes > 0 && inodeCfg[0].Size < uint64(req.CapacityRange.RequiredBytes))
+    {
+        sz := ((req.CapacityRange.RequiredBytes+4095)/4096)*4096
+        _, err := invokeCLI(ctxVars, []string{ "modify", "--inc_size", "1", "--resize", fmt.Sprintf("%d", sz), volName })
+        if (err != nil)
+        {
+            return nil, err
+        }
+        inodeCfg, err := invokeList(ctxVars, volName, true)
+        if (err != nil)
+        {
+            return nil, err
+        }
+        return &csi.ControllerExpandVolumeResponse{
+            CapacityBytes: int64(inodeCfg[0].Size),
+            // Node expansion is required for FS
+            NodeExpansionRequired: req.VolumeCapability == nil || req.VolumeCapability.GetBlock() == nil,
+        }, nil
+    }
+
+    return &csi.ControllerExpandVolumeResponse{
+        CapacityBytes: int64(inodeCfg[0].Size),
+        NodeExpansionRequired: false,
+    }, nil
 }
 
 // ControllerGetVolume get volume info
diff --git a/csi/src/identityserver.go b/csi/src/identityserver.go
index b1050411..dbe2bc6a 100644
--- a/csi/src/identityserver.go
+++ b/csi/src/identityserver.go
@@ -49,6 +49,13 @@ func (is *IdentityServer) GetPluginCapabilities(ctx context.Context, req *csi.Ge
                     },
                 },
             },
+            {
+                Type: &csi.PluginCapability_VolumeExpansion_{
+                    VolumeExpansion: &csi.PluginCapability_VolumeExpansion{
+                        Type: csi.PluginCapability_VolumeExpansion_OFFLINE,
+                    },
+                },
+            },
         },
     }, nil
 }