Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/twisted/internet/defer.py", line 575, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "/usr/lib/python2.7/site-packages/twisted/internet/defer.py", line 1213, in unwindGenerator
    return _inlineCallbacks(None, gen, Deferred())
  File "/usr/lib/python2.7/site-packages/twisted/internet/defer.py", line 1070, in _inlineCallbacks
    result = g.send(result)
  File "/usr/lib/python2.7/site-packages/buildbot/process/buildstep.py", line 605, in _startStep_3
    result = yield defer.maybeDeferred(self.start)
--- <exception caught here> ---
  File "/usr/lib/python2.7/site-packages/twisted/internet/defer.py", line 137, in maybeDeferred
    result = f(*args, **kw)
  File "/usr/lib/python2.7/site-packages/buildbot/steps/transfer.py", line 267, in start
    fileWriter = _FileWriter(masterdest, self.maxsize, self.mode)
  File "/usr/lib/python2.7/site-packages/buildbot/steps/transfer.py", line 46, in __init__
    os.makedirs(dirname)
  File "/usr/lib/python2.7/os.py", line 150, in makedirs
    makedirs(head, mode)
  File "/usr/lib/python2.7/os.py", line 157, in makedirs
    mkdir(name, mode)
exceptions.OSError: [Errno 13] Permission denied: '/srv/http/dl'