diff -r 000000000000 -r 6474c204b198 dom/system/gonk/nsVolumeStat.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/system/gonk/nsVolumeStat.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,39 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsVolumeStat.h"
+#include "nsString.h"
+
+namespace mozilla {
+namespace system {
+
+NS_IMPL_ISUPPORTS(nsVolumeStat, nsIVolumeStat)
+
+nsVolumeStat::nsVolumeStat(const nsAString& aPath)
+{
+  if (statfs(NS_ConvertUTF16toUTF8(aPath).get(), &mStat) != 0) {
+    memset(&mStat, 0, sizeof(mStat));
+  }
+}
+
+nsVolumeStat::~nsVolumeStat()
+{
+}
+
+/* readonly attribute long long totalBytes; */
+NS_IMETHODIMP nsVolumeStat::GetTotalBytes(int64_t* aTotalBytes)
+{
+  *aTotalBytes = mStat.f_blocks * mStat.f_bsize;
+  return NS_OK;
+}
+
+/* readonly attribute long long freeBytes; */
+NS_IMETHODIMP nsVolumeStat::GetFreeBytes(int64_t* aFreeBytes)
+{
+  *aFreeBytes = mStat.f_bfree * mStat.f_bsize;
+  return NS_OK;
+}
+
+} // system
+} // mozilla