Comment 0 for bug 1460692

Since rtslib has no synchronized access to configfs [1] it can happen that rtstool or rtslib try to access something that is no longer there because other Cinder request has removed the target.

These errors can happen on creating, attaching, detaching and deleting volumes, and resulting log messages are weird/misleading because the exception refers to a different volume-id from the one we were working on.

I have located different errors that are originated from this same issue:

1)
TRACE oslo.messaging.rpc.dispatcher Stderr: u'Traceback (most recent call last):
  File "/bin/cinder-rtstool", line 280, in <module>
    sys.exit(main())
  File "/bin/cinder-rtstool", line 251, in main
    get_targets()
  File "/bin/cinder-rtstool", line 162, in get_targets
    for t, dump in _get_targets(rtsroot):
  File "/bin/cinder-rtstool", line 51, in _get_targets
    return [(target, target.dump()) for target in rtsroot.targets]
  File "/usr/lib/python2.7/site-packages/rtslib/target.py", line 136, in dump
    d[\'tpgs\'] = [tpg.dump() for tpg in self.tpgs]
  File "/usr/lib/python2.7/site-packages/rtslib/target.py", line 430, in dump
    d[\'luns\'] = [lun.dump() for lun in self.luns]
  File "/usr/lib/python2.7/site-packages/rtslib/target.py", line 640, in dump
    (self.storage_object.plugin, self.storage_object.name)
  File "/usr/lib/python2.7/site-packages/rtslib/target.py", line 557, in _get_storage_object
    return tcm.StorageObject.so_from_path(alias_path)
  File "/usr/lib/python2.7/site-packages/rtslib/tcm.py", line 113, in so_from_path
    return so_mapping[so_type](so_name)
KeyError: \'lun\'

2)
Stderr: u'Traceback (most recent call last):
  File "/bin/cinder-rtstool", line 258, in <module>
    sys.exit(main())
  File "/bin/cinder-rtstool", line 229, in main
    get_targets()
  File "/bin/cinder-rtstool", line 141, in get_targets
    print(x.dump()[\'wwn\'])
  File "/usr/lib/python2.7/site-packages/rtslib/target.py", line 136, in dump
    d[\'tpgs\'] = [tpg.dump() for tpg in self.tpgs]
  File "/usr/lib/python2.7/site-packages/rtslib/target.py", line 427, in dump
    d = super(TPG, self).dump()
  File "/usr/lib/python2.7/site-packages/rtslib/node.py", line 218, in dump
    params[item] = self.get_parameter(item)
  File "/usr/lib/python2.7/site-packages/rtslib/node.py", line 190, in get_parameter
    return fread(path)
  File "/usr/lib/python2.7/site-packages/rtslib/utils.py", line 89, in fread
    with open(path, \'r\') as file_fd:
IOError: [Errno 2] No such file or directory: \'/sys/kernel/config/target/iscsi/iqn.2010-10.org.openstack:volume-1468da95-22a3-470c-8ac9-4b27cac8acb3/tpgt_1/param/IFMarkInt\'\n'

3)
2015-05-17 20:51:49.829 62162 ERROR cinder.brick.iscsi.iscsi [req-6981f2b5-2259-49d8-a8ce-6d41de344944 50a742bdfe4e4a8ca0ddc150fc648904 648ffe15b9fe4a1bba71e4643d4dbbf2 - - -] Unexpected error while running command. Command: sudo cinder-rootwrap /etc/cinder/rootwrap.conf cinder-rtstool delete iqn.2010-10.org.openstack:volume-ad12c1e0-6746-4bce-9b94-5df1cae4ee2a Exit code: 1 Stdout: '' Stderr: 'Traceback (most recent call last):
 File "/bin/cinder-rtstool", line 238, in <module>
 sys.exit(main())
 File "/bin/cinder-rtstool", line 224, in main
 delete(iqn)
 File "/bin/cinder-rtstool", line 151, in delete
 for x in rtsroot.storage_objects:
 File "/usr/lib/python2.7/site-packages/rtslib/root.py", line 86, in _list_storage_objects
 for so in StorageObject.all():
 File "/usr/lib/python2.7/site-packages/rtslib/tcm.py", line 102, in all
 yield cls.so_from_path(so_dir)
 File "/usr/lib/python2.7/site-packages/rtslib/tcm.py", line 117, in so_from_path
 return mapping[so_type](so_name)
 File "/usr/lib/python2.7/site-packages/rtslib/tcm.py", line 678, in __init__
 super(BlockStorageObject, self).__init__(name, \'lookup\')
 File "/usr/lib/python2.7/site-packages/rtslib/tcm.py", line 48, in __init__
 self._backstore = _Backstore(name, type(self), mode)
 File "/usr/lib/python2.7/site-packages/rtslib/tcm.py", line 785, in __init__
 (self._plugin, name))
rtslib.utils.RTSLibError: Storage object block/iqn.2010-10.org.openstack:volume-fb12df40-d1e3-4a4e-b47d-0162ce9573cc not found

The cleanest solution is synchronizing access in Cinder.

[1]: https://github.com/agrover/rtslib-fb/issues/36