diff --git a/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/UploadPackServlet.java b/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/UploadPackServlet.java
index 92d41a0ca..6d0d64fc6 100644
--- a/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/UploadPackServlet.java
+++ b/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/UploadPackServlet.java
@@ -107,7 +107,12 @@ public void doPost(final HttpServletRequest req,
 			up.setBiDirectionalPipe(false);
 			rsp.setContentType(RSP_TYPE);
 
-			final SmartOutputStream out = new SmartOutputStream(req, rsp);
+			final SmartOutputStream out = new SmartOutputStream(req, rsp) {
+				@Override
+				public void flush() throws IOException {
+					doFlush();
+				}
+			};
 			up.upload(getInputStream(req), out, null);
 			out.close();
 
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/TemporaryBuffer.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/TemporaryBuffer.java
index 6c421c5f5..101b6056b 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/TemporaryBuffer.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/TemporaryBuffer.java
@@ -138,6 +138,19 @@ public void write(final byte[] b, int off, int len) throws IOException {
 			overflow.write(b, off, len);
 	}
 
+	/**
+	 * Dumps the entire buffer into the overflow stream, and flushes it.
+	 *
+	 * @throws IOException
+	 *             the overflow stream cannot be started, or the buffer contents
+	 *             cannot be written to it, or it failed to flush.
+	 */
+	protected void doFlush() throws IOException {
+		if (overflow == null)
+			switchToOverflow();
+		overflow.flush();
+	}
+
 	/**
 	 * Copy all bytes remaining on the input stream into this buffer.
 	 *
@@ -260,6 +273,11 @@ private boolean reachedInCoreLimit() throws IOException {
 		if (blocks.size() * Block.SZ < inCoreLimit)
 			return false;
 
+		switchToOverflow();
+		return true;
+	}
+
+	private void switchToOverflow() throws IOException {
 		overflow = overflow();
 
 		final Block last = blocks.remove(blocks.size() - 1);
@@ -269,7 +287,6 @@ private boolean reachedInCoreLimit() throws IOException {
 
 		overflow = new BufferedOutputStream(overflow, Block.SZ);
 		overflow.write(last.buffer, 0, last.count);
-		return true;
 	}
 
 	public void close() throws IOException {