src/java.base/windows/native/libnio/ch/FileDispatcherImpl.c

*** 454,458 ****
--- 454,488 ----
                                 DUPLICATE_SAME_ACCESS);
      if (res == 0)
         JNU_ThrowIOExceptionWithLastError(env, "DuplicateHandle failed");
      return ptr_to_jlong(hResult);
  }
+ 
+ JNIEXPORT jint JNICALL
+ Java_sun_nio_ch_FileDispatcherImpl_setDirect0(JNIEnv *env, jclass this,
+                                               jobject fdObj, jobject buffer)
+ {
+     jint result = -1;
+ 
+     HANDLE orig = (HANDLE)(handleval(env, fdObj));
+ 
+     HANDLE modify = ReOpenFile(orig, 0, 0,
+             FILE_FLAG_NO_BUFFERING | FILE_FLAG_WRITE_THROUGH);
+ 
+     if (modify != INVALID_HANDLE_VALUE) {
+         DWORD sectorsPerCluster;
+         DWORD bytesPerSector;
+         DWORD numberOfFreeClusters;
+         DWORD totalNumberOfClusters;
+         LPCWSTR lpRootPathName = (*env)->GetDirectBufferAddress(env, buffer);
+         BOOL res = GetDiskFreeSpaceW(lpRootPathName,
+                                      &sectorsPerCluster,
+                                      &bytesPerSector,
+                                      &numberOfFreeClusters,
+                                      &totalNumberOfClusters);
+         if (res == 0) {
+             JNU_ThrowIOExceptionWithLastError(env, "DirectIO setup failed");
+         }
+         result = bytesPerSector;
+     }
+     return result;
+ }