Address Tim's comments

api/openapi-spec/swagger.json

@@ -82490,7 +82490,7 @@
       }
      },
      "dataSource": {
-      "description": "If specified, volume will be prepopulated with data from the DataSource.",
+      "description": "If specified, volume will be prepopulated with data from the specified data source. This depends on the provisioner for this volume being able to use the specified source. If the provisioner does not support it, it will fail to provision the volume.",
       "$ref": "#/definitions/io.k8s.api.core.v1.TypedLocalObjectReference"
      },
      "resources": {

api/swagger-spec/apps_v1.json

@@ -9516,7 +9516,7 @@
      },
      "dataSource": {
       "$ref": "v1.TypedLocalObjectReference",
-      "description": "If specified, volume will be prepopulated with data from the DataSource."
+      "description": "If specified, volume will be prepopulated with data from the specified data source. This depends on the provisioner for this volume being able to use the specified source. If the provisioner does not support it, it will fail to provision the volume."
      }
     }
    },

api/swagger-spec/apps_v1beta1.json

@@ -6798,7 +6798,7 @@
      },
      "dataSource": {
       "$ref": "v1.TypedLocalObjectReference",
-      "description": "If specified, volume will be prepopulated with data from the DataSource."
+      "description": "If specified, volume will be prepopulated with data from the specified data source. This depends on the provisioner for this volume being able to use the specified source. If the provisioner does not support it, it will fail to provision the volume."
      }
     }
    },

api/swagger-spec/apps_v1beta2.json

@@ -9520,7 +9520,7 @@
      },
      "dataSource": {
       "$ref": "v1.TypedLocalObjectReference",
-      "description": "If specified, volume will be prepopulated with data from the DataSource."
+      "description": "If specified, volume will be prepopulated with data from the specified data source. This depends on the provisioner for this volume being able to use the specified source. If the provisioner does not support it, it will fail to provision the volume."
      }
     }
    },

api/swagger-spec/v1.json

@@ -19311,7 +19311,7 @@
      },
      "dataSource": {
       "$ref": "v1.TypedLocalObjectReference",
-      "description": "If specified, volume will be prepopulated with data from the DataSource."
+      "description": "If specified, volume will be prepopulated with data from the specified data source. This depends on the provisioner for this volume being able to use the specified source. If the provisioner does not support it, it will fail to provision the volume."
      }
     }
    },

docs/api-reference/apps/v1/definitions.html

@@ -1019,7 +1019,7 @@ span.icon > [class^="icon-"], span.icon > [class*=" icon-"] { cursor: default; }
 </tr>
 <tr>
 <td class="tableblock halign-left valign-top"><p class="tableblock">dataSource</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">If specified, volume will be prepopulated with data from the DataSource.</p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">If specified, volume will be prepopulated with data from the specified data source. This depends on the provisioner for this volume being able to use the specified source. If the provisioner does not support it, it will fail to provision the volume.</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">true</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock"><a href="#_v1_typedlocalobjectreference">v1.TypedLocalObjectReference</a></p></td>
 <td class="tableblock halign-left valign-top"></td>

docs/api-reference/apps/v1beta1/definitions.html

@@ -1047,7 +1047,7 @@ span.icon > [class^="icon-"], span.icon > [class*=" icon-"] { cursor: default; }
 </tr>
 <tr>
 <td class="tableblock halign-left valign-top"><p class="tableblock">dataSource</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">If specified, volume will be prepopulated with data from the DataSource.</p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">If specified, volume will be prepopulated with data from the specified data source. This depends on the provisioner for this volume being able to use the specified source. If the provisioner does not support it, it will fail to provision the volume.</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">true</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock"><a href="#_v1_typedlocalobjectreference">v1.TypedLocalObjectReference</a></p></td>
 <td class="tableblock halign-left valign-top"></td>

docs/api-reference/apps/v1beta2/definitions.html

@@ -994,7 +994,7 @@ span.icon > [class^="icon-"], span.icon > [class*=" icon-"] { cursor: default; }
 </tr>
 <tr>
 <td class="tableblock halign-left valign-top"><p class="tableblock">dataSource</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">If specified, volume will be prepopulated with data from the DataSource.</p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">If specified, volume will be prepopulated with data from the specified data source. This depends on the provisioner for this volume being able to use the specified source. If the provisioner does not support it, it will fail to provision the volume.</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">true</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock"><a href="#_v1_typedlocalobjectreference">v1.TypedLocalObjectReference</a></p></td>
 <td class="tableblock halign-left valign-top"></td>

docs/api-reference/v1/definitions.html

@@ -696,7 +696,7 @@ span.icon > [class^="icon-"], span.icon > [class*=" icon-"] { cursor: default; }
 </tr>
 <tr>
 <td class="tableblock halign-left valign-top"><p class="tableblock">dataSource</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock">If specified, volume will be prepopulated with data from the DataSource.</p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">If specified, volume will be prepopulated with data from the specified data source. This depends on the provisioner for this volume being able to use the specified source. If the provisioner does not support it, it will fail to provision the volume.</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">true</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock"><a href="#_v1_typedlocalobjectreference">v1.TypedLocalObjectReference</a></p></td>
 <td class="tableblock halign-left valign-top"></td>

pkg/apis/core/types.go

@@ -413,7 +413,9 @@ type PersistentVolumeClaimSpec struct {
 	// This is an alpha feature and may change in the future.
 	// +optional
 	VolumeMode *PersistentVolumeMode
-	// If specified, volume will be prepopulated with data from the DataSource.
+	// If specified, volume will be prepopulated with data from the specified data source.
+	// This depends on the provisioner for this volume being able to use the specified source.
+	// If the provisioner does not support it, it will fail to provision the volume.
 	// +optional
 	DataSource *TypedLocalObjectReference
 }

pkg/apis/core/validation/validation.go

@@ -1501,6 +1501,9 @@ var supportedReclaimPolicy = sets.NewString(string(core.PersistentVolumeReclaimD
 
 var supportedVolumeModes = sets.NewString(string(core.PersistentVolumeBlock), string(core.PersistentVolumeFilesystem))
 
+var supportedDataSourceKinds = sets.NewString(string("VolumeSnapshot"))
+var supportedDataSourceAPIGroups = sets.NewString(string("snapshot.storage.k8s.io"))
+
 func ValidatePersistentVolume(pv *core.PersistentVolume) field.ErrorList {
 	metaPath := field.NewPath("metadata")
 	allErrs := ValidateObjectMeta(&pv.ObjectMeta, false, ValidatePersistentVolumeName, metaPath)
@@ -1827,16 +1830,13 @@ func ValidatePersistentVolumeClaimSpec(spec *core.PersistentVolumeClaimSpec, fld
 
 	if spec.DataSource != nil && !utilfeature.DefaultFeatureGate.Enabled(features.VolumeSnapshotDataSource) {
 		allErrs = append(allErrs, field.Forbidden(fldPath.Child("dataSource"), "VolumeSnapshotDataSource is disabled by feature-gate"))
-		spec.DataSource = nil
 	} else if spec.DataSource != nil {
 		if len(spec.DataSource.Name) == 0 {
-			allErrs = append(allErrs, field.Required(fldPath.Child("dataSource").Key(string("Name")), "VolumeSnapshotDataSource Name cannot be empty"))
-		}
-		if spec.DataSource.Kind != "VolumeSnapshot" {
-			allErrs = append(allErrs, field.Invalid(fldPath.Child("dataSource"), spec.DataSource.Kind, "expected DataSource Kind is VolumeSnapshot"))
-		}
-		if spec.DataSource.APIGroup != "snapshot.storage.k8s.io" {
-			allErrs = append(allErrs, field.Invalid(fldPath.Child("dataSource"), spec.DataSource.APIGroup, "expected DataSource APIGroup is snapshot.storage.k8s.io"))
+			allErrs = append(allErrs, field.Required(fldPath.Child("dataSource", "name"), ""))
+		} else if !supportedDataSourceKinds.Has(string(spec.DataSource.Kind)) {
+			allErrs = append(allErrs, field.NotSupported(fldPath.Child("dataSource"), spec.DataSource.Kind, supportedDataSourceKinds.List()))
+		} else if !supportedDataSourceAPIGroups.Has(string(spec.DataSource.APIGroup)) {
+			allErrs = append(allErrs, field.NotSupported(fldPath.Child("dataSource"), spec.DataSource.APIGroup, supportedDataSourceAPIGroups.List()))
 		}
 	}
 

staging/src/k8s.io/api/core/v1/generated.proto

@@ -2293,7 +2293,9 @@ message PersistentVolumeClaimSpec {
   // +optional
   optional string volumeMode = 6;
 
-  // If specified, volume will be prepopulated with data from the DataSource.
+  // If specified, volume will be prepopulated with data from the specified data source.
+  // This depends on the provisioner for this volume being able to use the specified source.
+  // If the provisioner does not support it, it will fail to provision the volume.
   // +optional
   optional TypedLocalObjectReference dataSource = 7;
 }

staging/src/k8s.io/api/core/v1/types.go

@@ -458,7 +458,9 @@ type PersistentVolumeClaimSpec struct {
 	// This is an alpha feature and may change in the future.
 	// +optional
 	VolumeMode *PersistentVolumeMode `json:"volumeMode,omitempty" protobuf:"bytes,6,opt,name=volumeMode,casttype=PersistentVolumeMode"`
-	// If specified, volume will be prepopulated with data from the DataSource.
+	// If specified, volume will be prepopulated with data from the specified data source.
+	// This depends on the provisioner for this volume being able to use the specified source.
+	// If the provisioner does not support it, it will fail to provision the volume.
 	// +optional
 	DataSource *TypedLocalObjectReference `json:"dataSource" protobuf:"bytes,7,opt,name=dataSource"`
 }

staging/src/k8s.io/api/core/v1/types_swagger_doc_generated.go

@@ -1210,7 +1210,7 @@ var map_PersistentVolumeClaimSpec = map[string]string{
 	"volumeName":       "VolumeName is the binding reference to the PersistentVolume backing this claim.",
 	"storageClassName": "Name of the StorageClass required by the claim. More info: https://kubernetes.io/docs/concepts/storage/persistent-volumes#class-1",
 	"volumeMode":       "volumeMode defines what type of volume is required by the claim. Value of Filesystem is implied when not included in claim spec. This is an alpha feature and may change in the future.",
-	"dataSource":       "If specified, volume will be prepopulated with data from the DataSource.",
+	"dataSource":       "If specified, volume will be prepopulated with data from the specified data source. This depends on the provisioner for this volume being able to use the specified source. If the provisioner does not support it, it will fail to provision the volume.",
 }
 
 func (PersistentVolumeClaimSpec) SwaggerDoc() map[string]string {