Naming system for hierarchically named computer accessible objects

• US 5,995,999 A
• Filed: 03/12/1997
• Issued: 11/30/1999
• Est. Priority Date: 03/12/1997
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Bharadhwaj, Rajeev
• Primary Examiner(s): Maung, Zarni
• Assistant Examiner(s): Najjar, Saleh
• Application Number:
  US08/815,748
• Time in Patent Office: 993 Days
• Field of Search: 395/200.3, 395/683, 395/300, 709/200, 709/303, 710/120
• US Class Current: 709/200
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

A naming system for resolution of hierarchically named computer accessible objects to respective object identifiers. The naming system includes a global namer module which is instantiated on multiple systems. Resolution of a hierarchical name begins at a first instance of the global namer module. The first instance resolves one or more successive portions of the hierarchical name to a respective object identifier(s). If the hierarchical name cannot be completely resolved at the first instance, the hierarhcial name is forwarded to a second instance which is referenced by an object identifier identified by the first instance. Resolution then continues at the second instance, and possibly at additional instances of the global namer module, until the last portion of the hierarchical name is resolved to an object identifier. The object identifier is then returned as that of the entire hierarchical name.

Claims

1. A method for resolving a hierarchical object name to an object identifier, said name being received from an originating client system which is associated with an originating name cache and is running an originating client program, said method comprising the steps of:

resolving the hierarchical object name to the object identifier at a global namer in a chain of global namers including a root global namer;

returning the object identifier and a node-path containing a list of global namers which were visited in resolving the hierarchical object name, to the originating client program; and

adding the hierarchical object name, the node-path, and the object identifier to the originating name cache.

2. The method of claim 1 further comprising the step of using the hierarchical object name and a list of associated access identifiers for looking-up in the originating name cache.

3. The method of claim 2 wherein the step of resolving at a root global namer comprises the further step of adding a client identifier to a client map associated with the root global namer.

4. The method of claim 3 wherein in the step of resolving if the object identifier is at a global namer which is not a root global namer, then the step of resolving further comprises the steps of:

identifying a preceding global namer which forwarded the hierarchical object name to a current global namer, which is resolving the hierarchical name, and to a succeeding global namer which will receive the hierarchical object name from the current global namer;

adding the preceding global namer, the succeeding global namer, and an object path to an external namer map (NAMER MAP S) associated with the current global namer;

forwarding the hierarchical object name and the point of continued resolution in the hierarchical object name to the succeeding global namer; and

updating the node-path.

5. The method of claim 4 comprising the further step of a global namer (NAMER X), upon receiving a contact from a client system, requesting the client system to flush its cache if the client system is identified in a pending cache flush map (CACHE FLUSH MAP X) associated with the NAMER X.

6. The method of claim 5 further comprising the steps of:

the client system flushing its cache; and

the NAMER X deleting an entry associated with the client system from the CACHE FLUSH MAP X.

7. A method for adding an object (OBJECT A) to a global namer (NAMER A), comprising the steps of:

maintaining a pending cache flush map;

receiving an object name and a list of associated access identifiers indicating programs having access to the OBJECT A;

creating an object identifier for identifying the OBJECT A; and

adding the object name, the list of associated access identifiers, and the object identifier to a name map associated with the NAMER A.

8. The method of claim 7 comprising the further step of adding the object to an object description table associated with the NAMER A.

9. The method of claim 8 comprising the further step of a global namer (NAMER X), upon receiving a contact from a client system, requesting the client system to flush its cache if the client system is identified in a pending cache flush map (CACHE FLUSH MAP X) associated with the NAMER X.

10. The method of claim 9 further comprising the steps of:

the client system flushing its cache; and

the NAMER X deleting an entry associated with the client system from the CACHE FLUSH MAP X.

11. A method for updating an object corresponding to an object identifier in a root global namer (NAMER ROOT U) associated with a root external namer map, a root client map, a root name map, and a root object description table, comprising the steps of:

checking the root external namer map for one or more succeeding external global namers (NAMERS U) corresponding to the root object identifier;

if no NAMER U is identified in the root external namer map then building a list of client identifiers (LIST U) from the root client map;

flushing respective caches associated with client systems identified in the LIST U;

updating the object in the root client map, in the root name map, and in the root object description table; and

deleting all entries in the external namer map where the object identifier appears in an updating object path list.

12. The method of claim 11 comprising the further step of building the LIST U from at least one NAMER U if the at least one NAMER U is identified in the root external namer map.

13. The method of claim 12 comprising the further step of sending a list of non-responding systems to a NAMER U which returns client identifiers.

14. The method of claim 13 further comprising the step of a global namer (NAMER X) maintaining in a pending cache flush map (CACHE FLUSH MAP X) a list of client systems having a pending cache flush.

15. The method of claim 14 comprising the further step of the NAMER X, upon receiving a contact from a client system, requesting the client system to flush its cache if the client system is identified in the CACHE FLUSH MAP X.

16. The method of claim 15 further comprising the steps of:

the client system flushing its cache; and

the NAMER X deleting an entry associated with the client system in the CACHE FLUSH MAP X.

17. The method of claim 15 comprising the further step of, in response to a non-responding system, adding an entry associated with the non-responding system to the CACHE FLUSH MAP X.

18. The method of claim 17 wherein the step of updating is selected from a group consisting of deleting and renaming the object.

19. The method of claim 18 comprising the further step of sending the object identifier to the at least one NAMER U.

20. The method of claim 19 further comprising the steps of:

an external global namer (NAMER U1) of the at least one NAMER U searching its external namer map for entries in which preceding external namers match the object identifier;

each object in an object-path corresponding to the matched entries sending its list of client identifiers and list of external global namers to the NAMER ROOT U;

the NAMER U1 sending the object identifier to external global namers referencing the object identifier; and

the external global namers sending their client identifier lists to the NAMER ROOT U.

21. A computer-readable medium comprising program instructions for causing a computer to resolve a hierarchical object name to an object identifier, said name being received from an originating client system which is associated with an originating name cache and is running an originating client program, by performing the steps of:

resolving the hierarchical object name to the object identifier at a global namer in a chain of global namers including a root global namer;

returning the object identifier and a node-path containing a list of global namers which were visited in resolving the hierarchical object name, to the originating client program; and

adding the hierarchical object name, the node-path, and the object identifier to the originating name cache.