Aliasing of exported paths in a storage system

• US 7,814,131 B1
• Filed: 04/30/2004
• Issued: 10/12/2010
• Est. Priority Date: 02/02/2004
• Status: Active Grant

• Current Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Muhlestein, Mark, Haynes, Thomas D., Noveck, David B.
• Primary Examiner(s): Mofiz; Apu M
• Assistant Examiner(s): Le; Jessica N
• Application Number:
  US10/837,120
• Time in Patent Office: 2,356 Days
• Field of Search: 707/100, 707/200
• US Class Current: 707/821
• CPC Class Codes: G06F 16/13 File access structures, e.g. distributed indices arrangements of input from, or output to, record carriers G06F3/06
• CPC Class Codes: G06F 21/6218 to a system of files or objects, e.g. local or distributed file system or database
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A storage system, such as a file server, uses pathname aliasing and exports a stored resource to clients by advertising to the clients a different pathname than the actual pathname of the resource.

Claims

1. A method of operation of a storage system comprising:

reading, by the storage system, an export rule associated with an exported resource in the storage system;

determining whether the export rule includes a directive that associates an advertised pathname of the exported resource with an actual pathname of the exported resource, the advertised pathname identifying a virtual export point and the actual pathname identifying a physical export point;

in response to a determination that the export rule does not include the directive, using the advertised pathname of the exported resource to obtain a filehandle of the exported resource, the filehandle being a value uniquely associated with the exported resource;

in response to a determination that the export rule includes the directive, determining whether the actual pathname of the export resource is the advertised pathname of another resource;

in response to a determination that the export rule includes the directive and that the actual pathname of the export resource is not the advertised pathname of another resource, using the actual pathname to obtain the filehandle of the exported resource without clients of the storage system having knowledge that the exported resource is stored according to the actual pathname; and

populating an entry for the exported resource in a data structure with the advertised pathname of the exported resource and the filehandle, the data structure for use in processing requests, from the clients of the storage system, to mount exported resources and enable the client to access the exported resource in the storage system with the filehandle.

2. The method as recited in claim 1, wherein the entry in the data structure further includes a permission relating to a client of the storage system with respect to the exported resource.

3. The method as recited in claim 2, wherein information associated with the exported resource further includes the permission, the method further comprising:

populating the entry for the exported resource in the data structure with the permission.

4. The method as recited in claim 2, further comprising:

receiving a request from a client of the storage system to mount the exported resource;

determining whether the client is permitted to access the exported resource based on the entry for the exported resource in the data structure; and

responding to the request according to whether the client is permitted to access the exported resource.

5. A storage system comprising:

a processor;

a storage interface through which to couple the storage system to a plurality of mass storage devices storing a resource;

a network interface through which to receive from a client a request for access to the resource; and

a memory having stored therein instructions which, when executed by the processor, cause the storage system to

read an export rule associated with the resource in the storage system;

determine whether the export rule includes a directive that associates an advertised pathname of the exported resource with an actual pathname of the exported resource, the advertised pathname identifying a virtual export point and the actual pathname identifying a physical export point;

in response to a determination that the export rule does not include the directive, use an advertised pathname of the resource to obtain a filehandle of the resource, the filehandle being a value uniquely associated with the resource;

in response to a determination that the export rule includes the directive, determine whether an actual pathname of the resource is the advertised pathname of another resource;

in response to a determination that the export rule includes the directive and that the actual pathname of the resource is not the advertised pathname of another resource, use the actual pathname to obtain the filehandle of the resource without client of the storage system having knowledge that the resource is stored according to the actual pathname; and

populate an entry for the resource in a data structure with the advertised pathname of the resource and the filehandle, the data structure for use in processing requests, from the client of the storage system, to mount the resource and enable the client to access the resource in the storage system with the filehandle.

6. The storage system as recited in claim 5, wherein the storage system determines access privileges of the client by determining whether the client is permitted to access the resource.

7. The storage system as recited in claim 6, wherein the memory further has stored therein instructions which, when executed by the processor, cause the storage system to return the filehandle of the resource in response to the request if the client is permitted to access the resource.

8. The storage system as recited in claim 5, wherein the data structure further contains the access privileges for the resource, and wherein the storage system determines the access privileges by accessing the data structure.

9. The storage system as recited in claim 5, wherein the storage system comprises a file server.

10. The storage system as recited in claim 5, wherein the storage system provides a set of clients with block-level access to stored data.

11. A storage system, comprising:

means for reading an export rule associated with an exported resource in the storage system;

means for determining whether the export rule includes a directive that associates an advertised pathname of the exported resource with an actual pathname of the exported resource, the advertised pathname identifying a virtual export point and the actual pathname identifying a physical export point;

means for using the advertised pathname of the exported resource to obtain a filehandle of the exported resource, in response to a determination that the export rule does not include the directive, the filehandle being a value uniquely associated with the exported resource;

means for determining whether the actual pathname of the export resource is the advertised pathname of another resource, in response to a determination that the export rule includes the directive;

means for using the actual pathname to obtain the filehandle of the exported resource without clients of the storage system having knowledge that the exported resource is stored according to the actual pathname, in response to a determination that the export rule includes the directive and that the actual pathname of the export resource is not the advertised pathname of another resource; and

means for populating an entry for the exported resource in a data structure with the advertised pathname of the exported resource and the filehandle, the data structure for use in processing requests, from the clients of the storage system, to mount exported resources and enable the client to access the exported resource in the storage system with the filehandle.

12. The storage system as recited in claim 11, wherein the entry in the data structure further includes a permission relating to a client of the storage system with respect to the exported resource.

13. The storage system as recited in claim 12, wherein information associated with the exported resource further includes the permission, the storage system further comprising:

means for populating the entry for the exported resource in the data structure with the permission.

14. The storage system as recited in claim 12, further comprising:

means for receiving a request from a client of the storage system to mount the exported resource;

means for determining whether the client is permitted to access the exported resource based on the entry for the exported resource in the data structure; and

means for responding to the request according to whether the client is permitted to access the exported resource.