Encoding metadata (pnfsid, space reservation, etc) in TURL:
Dmitry: We have other than performance improvement reasons to put reservation in TURL. Space Manager design is simplified, certain ambiguities are removed. Specific problem is related to retires to write into the same file. 
SRM performs permissions to write into the path. Space Manager performs checks if user has permission to write into the space reservation. 
Door still has to perform all checks again because it does not trust TURL. 

Proposal: SRM creates entry, when srm put is performed. Space Manager is not aware of file names, but only of pnfsid. 
SRM Makes file reservation, encodes only file request and door name in the turl, and srm request id.  Door verifies that no other door in the same door domain is writing in the same pnfsid.  Door requests additional info from SRM when it receives the encoded turl. SRM verifies the Authorization of the requester and SRM provides all the relevant info, space reservation, file metadata, path, expected door name, TURL expiration time, etc to the door in the response to the door request. If the turl has expired, released or SRM decides that the transfer should not continue for any other reason,  SRM returns error, that door propagates to the user.  Door verifies that door name is correct. Door performs the transfer. Its communication with Space Manager is now much more meaningful, Space Manager does not emulate Pool Manager. 

Make all ids in SRM positive. 

In case of implicit space reservation door needs to make an explicit space reservation (from the point of view of Space Manager) itself. 

Re-factoring spaces, integration of all space/location management services
Discussion postponed.