diff -r 238c37e4c395 Modules/posixmodule.c
--- a/Modules/posixmodule.c	Sat Aug 03 11:39:39 2013 +0200
+++ b/Modules/posixmodule.c	Fri Aug 09 00:46:14 2013 -0400
@@ -10143,6 +10143,14 @@
             goto exit;
         }
 
+        /*
+         * On Linux using ZFS (native), if attr is >128 bytes,
+         * and we ask for 128 bytes, we successfully get 128 bytes
+         * and no error is indicated.  So we have to retry.
+         */
+        if ((result == buffer_size) && (buffer_size != XATTR_SIZE_MAX))
+            continue;
+
         if (result != buffer_size) {
             /* Can only shrink. */
             _PyBytes_Resize(&buffer, result);