System and method for mapping file block numbers to logical block addresses

• US 7,437,530 B1
• Filed: 04/24/2003
• Issued: 10/14/2008
• Est. Priority Date: 04/24/2003
• Status: Expired due to Term

• Current Assignee: NetApp, Inc.
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Rajan, Vijayan
• Primary Examiner(s): Shah; Sanjiv
• Assistant Examiner(s): DILLER, JESSE DAVID
• Application Number:
  US10/422,494
• Time in Patent Office: 2,000 Days
• Field of Search: 711/206
• US Class Current: 711/206
• CPC Class Codes: G06F 12/1027 using associative or pseudo-associative address translation means, e.g. translation look-aside buffer [TLB]
• CPC Class Codes: G06F 12/1036 for multiple virtual address spaces, e.g. segmentation G06F12/1045 takes precedence
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0683 Plurality of storage devices
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]

Abstract

A system and method for mapping file block numbers (FBNs) to logical block addresses (LBAs) is provided. The system and method performs the mapping of FBNs to LBAs in a file system layer of a storage operating system, thereby enabling the use of clients in a storage environment that have not been modified to incorporate mapping tables. As a result, a client may send data access requests to the storage system utilizing FBNs and have the storage system perform the appropriate mapping to LBAs.

Claims

1. A method for translating a file based data access request to a computer storage system, comprising:

receiving at a network interface the file based data read request from a client, the network interface attached to a wide area computer network (WAN);

writing the file based data read request to a virtual disk which appears to the client as a file based storage device;

writing the file based data read request from the virtual disk to a block based file system of the storage system;

maintaining a mapping of the file block numbers to a set of logical block addresses of a storage medium by the computer data storage system, the maintaining done with the client not having knowledge of a layout of the storage medium;

mapping the file based data read request into block based block access addresses in response to the mapping of the file block numbers to a set of logical block addresses of the storage medium;

accessing data requested by the file based data read request from block based storage devices in response to the block access numbers;

transferring the data requested to the network interface, and sending the data to the client over the WAN.

2. The method of claim 1 wherein a file block number comprises a sequentially increasing value identifying a specific location within a file.

3. The method of claim 1 wherein a logical block address further comprises a value identifying a particular block stored on a storage device associated with the storage system.

4. The method of claim 3 wherein the storage device further comprises a set of disks.

5. The method of claim 1 wherein the step of mapping the file block numbers to a set of logical block addresses is performed by a storage operating system executing on the storage system.

6. The method of claim 1 wherein the step of mapping the file block numbers to a set of associated logical block addresses is performed by a mapping function within a file system executing on a storage operating system of the storage system.

7. The method of claim 1 wherein the step of mapping utilizes a mapping table.