diff --git a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDocumentsProvider.java b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDocumentsProvider.java
index 3fcc600e67f07..6b2c1eeef694b 100644
--- a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDocumentsProvider.java
+++ b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpDocumentsProvider.java
@@ -485,6 +485,24 @@ public class MtpDocumentsProvider extends DocumentsProvider {
         }
     }
 
+    @Override
+    public boolean isChildDocument(String parentDocumentId, String documentId) {
+        try {
+            Identifier identifier = mDatabase.createIdentifier(documentId);
+            while (true) {
+                if (parentDocumentId.equals(identifier.mDocumentId)) {
+                    return true;
+                }
+                if (identifier.mDocumentType == MtpDatabaseConstants.DOCUMENT_TYPE_DEVICE) {
+                    return false;
+                }
+                identifier = mDatabase.getParentIdentifier(identifier.mDocumentId);
+            }
+        } catch (FileNotFoundException error) {
+            return false;
+        }
+    }
+
     void openDevice(int deviceId) throws IOException {
         synchronized (mDeviceListLock) {
             if (mDeviceToolkits.containsKey(deviceId)) {
diff --git a/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDocumentsProviderTest.java b/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDocumentsProviderTest.java
index 194e8c727c7a6..ef2e0a58903c8 100644
--- a/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDocumentsProviderTest.java
+++ b/packages/MtpDocumentsProvider/tests/src/com/android/mtp/MtpDocumentsProviderTest.java
@@ -854,6 +854,18 @@ public class MtpDocumentsProviderTest extends AndroidTestCase {
         assertEquals("19", path.getPath().get(2));
     }
 
+    public void testIsChildDocument() throws Exception {
+        setupProvider(MtpDatabaseConstants.FLAG_DATABASE_IN_MEMORY);
+        setupRoots(0, new MtpRoot[] { new MtpRoot(0, 0, "Storage", 1000, 1000, "") });
+        setupHierarchyDocuments("1");
+        assertTrue(mProvider.isChildDocument("1", "1"));
+        assertTrue(mProvider.isChildDocument("1", "14"));
+        assertTrue(mProvider.isChildDocument("2", "14"));
+        assertTrue(mProvider.isChildDocument("5", "14"));
+        assertFalse(mProvider.isChildDocument("3", "14"));
+        assertFalse(mProvider.isChildDocument("6", "14"));
+    }
+
     private void setupProvider(int flag) {
         mDatabase = new MtpDatabase(getContext(), flag);
         mProvider = new MtpDocumentsProvider();