SYSTEM AND METHOD FOR NETWORK FILE SYSTEM SERVER REPLICATION USING REVERSE PATH LOOKUP

• US 20140122428A1
• Filed: 10/26/2012
• Published: 05/01/2014
• Est. Priority Date: 09/16/2011
• Status: Active Grant

• Current Assignee: CA, Inc. (d/b/a CA Technologies) (Broadcom, Inc.)
• Original Assignee: CA, Inc. (d/b/a CA Technologies) (Broadcom, Inc.)
• Inventors: Shang, Guoxian, Chang, Baojian, Zhou, Dongmei
• Granted Patent: US 9,552,367 B2
• Time in Patent Office: Days
• US Class Current: 707/623
• CPC Class Codes: G06F 11/202 where processing functionality is redundant redundant communication control functionality G06F11/2005, redundant storage control functionality G06F11/2089
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component
• CPC Class Codes: G06F 11/2048 where the redundant components share neither address space nor persistent storage
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: G06F 16/1794 Details of file format conversion
• CPC Class Codes: G06F 16/184 implemented as replicated file system

Abstract

The system and method described herein may use reverse path lookup to build mappings between file handles that represent network file system objects and full path names associated therewith and distinguish hard links between different file system objects having the same identifier with different parents or file names. The mappings and information distinguishing the hard links may then be cached to enable replicating changes to the file system. For example, a server may search the cached information using a file handle associated with a changed file system object to obtain the file name and full path name associated therewith. The server may then send the file name and full path name and metadata describing how the file system object was changed to a replica host, which may then replicate the change to the file system object.

Claims

1. A system for replicating a network file system using reverse path lookup, comprising:

a master file system;

a master host having one or more processors configured to;

receive a request to apply one or more changes to the master file system and a file handle that represents an object associated with the one or more changes to the master file system from a client computer;

interpret the file handle to determine the object that the file handle represents, apply the one or more changes to the object within the master file system, and determine a full path name that the object has within the master file system based on a parent that the object has within the master file system;

build a mapping between an inode number that identifies the object within the master file system and the full path name associated with the object; and

transmit the mapping and metadata that describes the one or more changes to the master file system to a replica host configured to replicate the one or more changes using the mapping and the metadata.

2. The system of claim 1, further comprising a cache configured to store the mapping between the inode number and the full path name, wherein the one or more processors reference the cached mapping to replicate one or more subsequent changes to the object.

3. The system of claim 1, wherein the one or more processors are further configured to:

inspect an inode corresponding to the inode number that identifies the object to determine whether the object represents a directory or a file within the master file system; and

read an entry in the inode that points to a parent directory associated with the inode in response to determining that the object represents a directory, wherein the parent directory represents the parent that the directory object has within the master file system.

4. The system of claim 1, wherein the one or more processors are further configured to:

inspect an inode corresponding to the inode number that identifies the object to determine whether the object represents a directory or a file within the master file system; and

read an entry in the inode that points to a current directory that contains the inode in response to determining that the object represents a file, wherein the current directory represents the parent that the file object has within the master file system.

5. The system of claim 1, wherein the one or more processors are further configured to:

store the mapping between the inode number and the full path name on a disk;

apply one or more subsequent changes to the object in response to receiving one or more subsequent requests to change the object that the file handle represents; and

reference the mapping stored on the disk to replicate the one or more subsequent changes in response to applying the one or more subsequent changes to the object.

6. The system of claim 5, wherein the one or more processors are configured to store the mapping between the inode number and the full path name in a device-specific mapping file based on a device identifier or file system identifier associated with the file handle.

7. The system of claim 5, wherein the one or more processors are configured to store the mapping between the inode number and the full path name in a binary balance tree.

8. The system of claim 1, wherein the one or more processors are further configured distinguish one or more hard links associated with the object in response to determining that one or more other objects having different parents or file names from the object share the inode number that identifies the object.

9. The system of claim 8, wherein the one or more processors are configured to use the mapping between the inode number and the full path name associated with the object to distinguish the one or more hard links if the object and the one or more other objects reside in different directories.

10. The system of claim 8, wherein the one or more processors are configured to add the file names associated with the object and the one or more other objects to the mapping between the inode number and the full path name associated with the object to distinguish the one or more hard links if the object and the one or more other objects reside in a common directory.

11. A method for replicating a network file system using reverse path lookup, comprising:

receiving, at a master host, a request to apply one or more changes to a master file system from a client computer, wherein the request includes a file handle that represents an object associated with the one or more changes to the master file system;

interpreting the file handle to determine the object that the file handle represents at the master host, wherein the master host interprets the file handle to apply the one or more changes to the object within the master file system and determine a full path name that the object has within the master file system based on a parent that the object has within the master file system;

building, at the master host, a mapping between an inode number that identifies the object within the master file system and the full path name associated the object; and

transmitting the mapping and metadata that describes the one or more changes to the master file system from the master host to a replica host, wherein the replica host replicates the one or more changes using the transmitted mapping and the transmitted metadata.

12. The method of claim 11, further comprising caching the mapping between the inode number and the full path name, wherein a replication client that executes on the master host references the cached mapping to replicate one or more subsequent changes to the object.

13. The method of claim 11, further comprising;

inspecting an inode corresponding to the inode number that identifies the object to determine whether the object represents a directory or a file within the master file system; and

reading an entry in the inode that points to a parent directory associated with the inode in response to determining that the object represents a directory, wherein the parent directory represents the parent that the directory object has within the master file system.

14. The method of claim 11, further comprising:

inspecting an inode corresponding to the inode number that identifies the object to determine whether the object represents a directory or a file within the master file system; and

reading an entry in the inode that points to a current directory that contains the inode in response to determining that the object represents a file, wherein the current directory represents the parent that the file object has within the master file system.

15. The method of claim 11, further comprising:

storing the mapping between the inode number and the full path name on a disk;

applying one or more subsequent changes to the object in response to receiving one or more subsequent requests to change the object that the file handle represents; and

referencing the mapping stored on the disk to replicate the one or more subsequent changes in response to applying the one or more subsequent changes to the object.

16. The method of claim 15, wherein disk stores the mapping between the inode number and the full path name in a device-specific mapping file based on a device identifier or file system identifier associated with the file handle.

17. The method of claim 15, wherein the disk stores the mapping between the inode number and the full path name in a binary balance tree.

18. The method of claim 11, further comprising distinguishing one or more hard links associated with the object in response to the master host determining that one or more other objects having different parents or file names from the object share the inode number that identifies the object.

19. The method of claim 18, wherein the master host uses the mapping between the inode number and the full path name associated with the object to distinguish the one or more hard links if the object and the one or more other objects reside in different directories.

20. The method of claim 18, wherein the master host adds the file names associated with the object and the one or more other objects to the mapping between the inode number and the full path name associated with the object to distinguish the one or more hard links if the object and the one or more other objects reside in a common directory.