diff --git a/addons/document/document.py b/addons/document/document.py
index 3450d3a51a4..21aa59661a7 100644
--- a/addons/document/document.py
+++ b/addons/document/document.py
@@ -695,8 +695,9 @@ class document_file(osv.osv):
             import urllib
             datas=base64.encodestring(urllib.urlopen(vals['link']).read())
         else:
-            datas=vals.get('datas',False)
-        vals['file_size']= len(datas)
+            datas = vals.get('datas',False)
+        
+        vals['file_size']= datas and len(datas) or 0
         if not self._check_duplication(cr,uid,vals):
             raise except_orm(_('ValidateError'), _('File name must be unique!'))
         result = super(document_file,self).create(cr, uid, vals, context)