update cell error

[skywalker]

I updated the cell info and the response is as follows:
{
    "computeFault": {
        "message": "The server has either erred or is incapable of performing the requested operation.",
        "code": 500
    }
}

I found error in nova-cells.log:
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack Traceback (most recent call last):
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/__init__.py", line 81, in __call__
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return req.get_response(self.application)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/request.py", line 1296, in send
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack application, catch_exc_info=False)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/request.py", line 1260, in call_application
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack app_iter = application(self.environ, start_response)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return resp(environ, start_response)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/keystoneclient/middleware/auth_token.py", line 450, in __call__
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return self.app(env, start_response)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return resp(environ, start_response)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return resp(environ, start_response)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return resp(environ, start_response)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/routes/middleware.py", line 131, in __call__
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack response = self.app(environ, start_response)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 144, in __call__
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return resp(environ, start_response)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 130, in __call__
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack resp = self.call_func(req, *args, **self.kwargs)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 195, in call_func
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return self.func(req, *args, **kwargs)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/wsgi.py", line 890, in __call__
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack content_type, body, accept)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/wsgi.py", line 942, in _process_stack
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack action_result = self.dispatch(meth, request, action_args)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/wsgi.py", line 1022, in dispatch
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return method(req=request, **action_args)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/compute/contrib/cells.py", line 257, in update
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return dict(cell=_scrub_cell(cell))
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/compute/contrib/cells.py", line 118, in _scrub_cell
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack cell_info = _filter_keys(cell, keys)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack File "/usr/lib/python2.7/dist-packages/nova/api/openstack/compute/contrib/cells.py", line 110, in _filter_keys
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack return dict((k, v) for k, v in item.iteritems() if k in keys)
2013-07-07 23:55:20.777 31477 TRACE nova.api.openstack AttributeError: 'Query' object has no attribute 'iteritems'

I viewed the code and found that:
@require_admin_context
def cell_update(context, cell_name, values):
    session = get_session()
    with session.begin():
        cell = _cell_get_by_name_query(context, cell_name, session=session)
        cell.update(values)
    return cell

The method nova.db.sqlalchemy.api.cell_update() returns a 'Query' object.

def _filter_keys(item, keys):
    """
    Filters all model attributes except for keys
    item is a dict

    """
    return dict((k, v) for k, v in item.iteritems() if k in keys)

The method nova.api.openstack.compute.contrib.cells_filter_keys() uses the 'Query' object as a dict.

This bring on the error.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/45718

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/45718
Committed: http://github.com/openstack/nova/commit/f10f67dcc82dc7fda5aaf546b145dad34db82f7b
Submitter: Jenkins
Branch: master

commit f10f67dcc82dc7fda5aaf546b145dad34db82f7b
Author: Russell Bryant <email address hidden>
Date: Mon Sep 9 13:50:04 2013 -0400

    Don't return query from db API

    The cell_update() method of the sqlalchemy db API returned a Query when
    it really intended to return a Cell. Fix this and tweak the db API test
    so that it verifies that the result of this method is a Cell.

    Change-Id: I7ab7ea19f00ac2e8c2c73afe8a14f331940b4580
    Closes-bug: #1198796

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/grizzly
Review: https://review.openstack.org/48567