Index: subversion/libsvn_ra_serf/util.c
===================================================================
--- subversion/libsvn_ra_serf/util.c	(revision 1500021)
+++ subversion/libsvn_ra_serf/util.c	(working copy)
@@ -640,12 +640,17 @@
                apr_pool_t *scratch_pool)
 {
   serf_bucket_alloc_t *allocator = serf_request_get_alloc(request);
-
-  svn_spillbuf_t *buf;
   svn_boolean_t set_CL = session->http10 || !session->using_chunked_requests;
+  apr_uint64_t request_body_len;
 
-  if (set_CL && body_bkt != NULL)
+  if (body_bkt)
+    request_body_len = serf_bucket_get_remaining(body_bkt);
+  else
+    request_body_len = 0;
+
+  if (set_CL && request_body_len == SERF_LENGTH_UNKNOWN)
     {
+      svn_spillbuf_t *buf;
       /* Ugh. Use HTTP/1.0 to talk to the server because we don't know if
          it speaks HTTP/1.1 (and thus, chunked requests), or because the
          server actually responded as only supporting HTTP/1.0.
@@ -663,6 +668,7 @@
       body_bkt = svn_ra_serf__create_sb_bucket(buf, allocator,
                                                request_pool,
                                                scratch_pool);
+      request_body_len = svn_spillbuf__get_size(buf);
     }
 
   /* Create a request bucket.  Note that this sucker is kind enough to
@@ -672,12 +678,9 @@
 
   /* Set the Content-Length value. This will also trigger an HTTP/1.0
      request (rather than the default chunked request).  */
-  if (set_CL)
+  if (request_body_len != SERF_LENGTH_UNKNOWN)
     {
-      if (body_bkt == NULL)
-        serf_bucket_request_set_CL(*req_bkt, 0);
-      else
-        serf_bucket_request_set_CL(*req_bkt, svn_spillbuf__get_size(buf));
+      serf_bucket_request_set_CL(*req_bkt, request_body_len);
     }
 
   *hdrs_bkt = serf_bucket_request_get_headers(*req_bkt);