Using a file for associating the file with a tree quota in a file server

• US 20050050107A1
• Filed: 09/03/2003
• Published: 03/03/2005
• Est. Priority Date: 09/03/2003
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Mane, Virendra M., Zheng, Jiannan
• Granted Patent: US 7,849,112 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

To avoid the need for storing a tree quota identifier attribute for every file in a quota tree, a tree quota identifier is included in the file handle returned by the file server to a client in response to a directory lookup request. The file server discovers that the file is in a quota tree when searching along a path specified by the file pathname and finding a directory having a tree quota identifier. The file server responds to a client request for changing the storage resources used by the file by inspecting the file handle and upon finding the tree quota identifier in the file handle, using the tree quota identifier to index a tree quota database to find usage and limits for the tree quota. The file server checks the limits against any increase in the storage resources for the file, and updates the usage.

Claims

1. A method of maintaining quotas for storage resources used by a file server for storing files in selected directory trees of a file system, the method including:

(a) the file server responding to a client request specifying a file in the file system by performing a search for the file in the file system, and upon finding that the file is in a directory tree having a quota of the storage resources, returning a file handle including a tree quota identifier identifying the quota of the directory tree;

(b) the file server responding to a client request for increasing storage resources used by the file, the client request for increasing storage resources used by the file including the file handle, the file server responding to the client request for increasing storage resources used by the file by inspecting the file handle and upon finding the tree quota identifier in the file handle, using the tree quota identifier to find the quota identified by the tree quota identifier, and checking whether the client request for increasing storage resources used by the file can be satisfied without exceeding the quota identified by the tree quota identifier.

2. The method as claimed in claim 1, which includes the file server maintaining a quota tree database of the quotas for the selected directory trees, and wherein the tree quota identifier is an index into the quota tree database for a database entry for the quota identified by the tree quota identifier.

3. The method as claimed in claim 2, wherein the database entry indexed by the tree quota identifier includes a file handle for a root directory of the directory tree having the quota identified by the tree quota identifier, a usage value specifying an amount of the storage resources presently used for storing files in the directory tree having the quota identified by the tree quota identifier and at least one limit value specifying the quota of storage resources for storing files in the directory tree having the quota identified by the tree quota identifier.

4. The method as claimed in claim 1, which further includes the file server responding to a request to establish a tree quota for a specified directory in the file system by searching the file system for the specified directory, and returning an error upon finding that the specified directory is included in a directory tree already having a tree quota.

5. The method as claimed in claim 1, which further includes the file server responding to a request to establish a tree quota for a specified directory in the file system by searching the file system for the specified directory, and returning an error upon finding that the specified directory is already present.

6. The method as claimed in claim 1, which further includes the file server responding to a request to establish a tree quota for a specified directory in the file system by creating the specified directory and associating a tree quota identifier with the specified directory.

7. The method as claimed in claim 1, which further includes the file server responding to a request to establish a tree quota for a specified directory in the file system by storing a unique tree quota identifier in a node of the directory, the node of the directory and the unique tree quota identifier later being accessed during a search through the file system for a file in the specified directory.

8. The method as claimed in claim 7, which includes the file server pinning the node of the specified directory in a file system cache memory.

9. The method as claimed in claim 7, which includes the file server storing the unique tree quota identifier in an entry of a tree quota database, the entry of the tree quota database also including at least one limit value specifying a quota of storage resources used by the file server for storing files in a directory tree having the specified directory as its root directory.

10. The method as claimed in claim 1, which further includes the file server responding to a client request for changing the size of a specified file, the client request for changing the size of including a file handle for the specified file, the file server responding to the client request for changing the size of the specified file by inspecting the file handle for the specified file and upon finding a tree quota identifier in the file handle for the specified file, using the tree quota identifier for the specified file to find a usage for the quota identified by the tree quota identifier for the specified file, and updating the usage for quota identified by the tree quota identifier for the specified file.

11. The method as claimed in claim 1, which further includes the file server responding to a request to rename a specified file in the file system from an old file name to a new file name, and upon finding that the old file name is in a directory tree having a quota of the storage resources and the new file name is not in the same directory tree having the quota of storage resources as the old file name, returning an error.

12. The method as claimed in claim 1, which further includes the file server responding to a request to turn off a tree quota for a specified directory in the file system by searching for the specified directory in the file system, and upon finding that the specified directory is not empty, returning an error.

13. The method as claimed in claim 1, which further includes the file server responding to a request to turn off a tree quota for a specified directory in the file system by deleting the specified directory.

14. A method of maintaining quotas for storage resources used by a file server for storing files in selected directory trees of a file system, the file server having a tree quota database of usage values of the storage resources and limit values for the storage resources for the selected directory trees of the file system, the usage values and limit values being indexed by tree quota identifiers associated with root directories of the selected directory trees, the method including:

(a) the file server responding to a client request specifying a file in the file system by performing a search for the file in the file system, and upon finding that the file is in a directory tree having a quota of the storage resources, returning a file handle including a tree quota identifier identifying the quota of the storage resources;

(b) the file server responding to a client request for increasing storage resources used by the file, the client request for increasing storage resources used by the file including the file handle, the file server responding to the client request for increasing storage resources used by the file by inspecting the file handle and upon finding the tree quota identifier in the file handle, using the tree quota identifier to index the tree quota database to find the quota identified by the tree quota identifier, and checking whether the client request for increasing storage resources used by the file can be satisfied without exceeding the limit value of the quota identified by the tree quota identifier; and

when the client request for increasing storage resources used by the file can be satisfied without exceeding the limit value of the quota identified by the tree quota identifier, increasing the usage for the quota identified by the tree quota identifier, and satisfying the client request.

15. A file server comprising:

storage for storing a file system; and

a processor programmed for responding to client requests for access to the file system and for maintaining quotas for storage resources used for storing files in selected directory trees of the file system,

wherein the processor is programmed for responding to a client request specifying a file in the file system by performing a search for the file in the file system, and upon finding that the file is in a directory tree having a quota of the storage resources, returning a file handle including a tree quota identifier identifying the quota of the storage resources; and

wherein the processor is programmed for responding to a client request for increasing storage resources used by the file, the client request for increasing storage resources used by the file including the file handle, and the processor is programmed for responding to the client request for increasing storage resources used by the file by inspecting the file handle and upon finding the tree quota identifier in the file handle, using the tree quota identifier to find the quota identified by the tree quota identifier, and checking whether the client request for increasing storage resources used by the file can be satisfied without exceeding the quota identified by the tree quota identifier.

16. The file server as claimed in claim 15, which includes a quota tree database of the selected directory trees of the file system having the quotas for the storage resources, and wherein the tree quota identifier is an index into the quota tree database for a database entry for the quota identified by the quota tree identifier.

17. The file server as claimed in claim 16, wherein the database entry indexed by the tree quota identifier includes a file handle for a root directory of the directory tree having the quota identified by the tree quota identifier, a usage value specifying an amount of the storage resources presently used for storing files in the directory tree having the quota identified by the tree quota identifier and at least one limit value specifying the quota identified by the tree quota identifier.

18. The file server as claimed in claim 15, wherein the processor is programmed for responding to a request to establish a tree quota for a specified directory in the file system by searching the file system for the specified directory, and returning an error upon finding that the specified directory is included in a directory tree already having a tree quota.

19. The file server as claimed in claim 15, wherein the processor is programmed for responding to a request to establish a tree quota for a specified directory in the file system by searching the file system for the specified directory, and returning an error upon finding that the specified directory is already present.

20. The file server as claimed in claim 15, wherein the processor is further programmed for responding to a request to establish a tree quota for a specified directory in the file system by creating the specified directory and associating a tree quota identifier with the specified directory.

21. The file server as claimed in claim 15, wherein the processor is programmed for responding to a request to establish a tree quota for a specified directory in the file system by storing a unique tree quota identifier in a node of the directory, the node of the directory and the unique tree identifier later being accessed during a search through the file system for a file in the specified directory.

22. The file server as claimed in claim 21, wherein the processor has a file system cache memory, and wherein the processor is programmed for pinning the node of the specified directory in the file system cache memory.

23. The file server as claimed in claim 21, wherein the processor is programmed for storing the unique tree identifier in an entry of a tree quota database, the entry of the tree quota database also including at least one limit value specifying a quota of storage resources used by the file server for storing files in a directory tree having the specified directory as its root directory.

24. The file server as claimed in claim 15, wherein the processor is further programmed for responding to a client request for changing the size of a specified file, the client request for changing the size of including a file handle for the specified file, the file server responding to the client request for changing the size of the specified file by inspecting the file handle for the specified file and upon finding a tree quota identifier in the file handle for the specified file, using the tree quota identifier for the specified file to find a usage for the quota tree identified by the tree quota identifier for the specified file, and updating the usage for the quota tree identified by the tree quota identifier for the specified file.

25. The file server as claimed in claim 15, wherein the processor is further programmed for responding to a request to rename a specified file in the file system from an old file name to a new file name, and upon finding that the old file name is in a directory tree having a quota of the storage resources and the new file name is not in the same directory tree having the quota of storage resources as the old file name, returning an error.

26. The file server as claimed in claim 15, wherein the processor is further programmed for responding to a request to turn off a tree quota for a specified directory in the file system by searching for the specified directory in the file system, and upon finding that the specified directory is not empty, returning an error.

27. The method as claimed in claim 15, wherein the processor is further programmed for responding to a request to turn off a tree quota for a specified directory in the file system by deleting the specified directory.

28. A file server comprising:

storage for storing a file system; and

a processor programmed for responding to client requests for access to the file system and for maintaining quotas for storage resources used for storing files in selected directory trees of the file system,

wherein the processor is programmed for maintaining a tree quota database of usage values of the storage resources and limit values for the storage resources for the selected directory trees of the file system, the usage values and limit values being indexed by tree quota identifiers associated with root directories of the selected directory trees;

wherein the processor is programmed for responding to a client request specifying a file in the file system by performing a search for the file in the file system, and upon finding that the file is in a directory tree having a quota of the storage resources, returning a file handle including a tree quota identifier identifying the quota of the storage resources; and

wherein the processor is programmed for responding to a client request for increasing storage resources used by the file, the client request for increasing storage resources used by the file including the file handle, and the processor is programmed for responding to the client request for increasing storage resources used by the file by inspecting the file handle and upon finding the tree quota identifier in the file handle, using the tree quota identifier to index the tree quota database to find the quota identified by the tree quota identifier, and checking whether the client request for increasing storage resources used by the file can be satisfied without exceeding the quota of storage resources for storing files in the directory tree identified by the tree quota identifier; and

when the client request for increasing storage resources used by the file can be satisfied without exceeding the limit value of the quota identified by the tree quota identifier, increasing the usage for the quota identified by the tree quota identifier, and satisfying the client request.