System and method for zero copy block protocol write operations

• US 7,849,274 B2
• Filed: 04/02/2007
• Issued: 12/07/2010
• Est. Priority Date: 12/29/2003
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Pittman, Joseph C.
• Primary Examiner(s): Nguyen; Hiep T
• Application Number:
  US11/732,057
• Publication Number:
  US 20070208821A1
• Time in Patent Office: 1,345 Days
• Field of Search: None
• US Class Current: 711/154
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

A system and method for zero copy block protocol write operations obviates the need to copy the contents of memory buffers (mbufs) at a storage system. A storage operating system of the storage system receives data from a network and stores the data in chains of mbufs having various lengths. An iSCSI driver processes (interprets) the received mbufs and passes the appropriate data and interpreted command to a SCSI target module of the storage operating system. The SCSI target module utilizes the mbufs and the data contained therein to perform appropriate write operations in response to write requests received from clients.

Claims

1. A method, comprising:

receiving a write request at a network protocol stack of a storage operating system executing on a storage system, the write request comprising a write command and data to write to a data storage device of the storage system;

storing the write request into a network memory buffer of the storage system, the network memory buffer referenced by one or more pointers; and

passing the one or more pointers that reference the network memory buffer to a virtualization system of the storage operating system, the virtualization system processing the write command to write the data to the data storage device.

2. The method of claim 1, wherein the data is an iSCSI protocol data unit.

3. The method of claim 1, wherein the data storage device is a disk.

4. The method of claim 1, further comprising performing a function call by an iSCSI module of the virtualization system.

5. The method of claim 1, further comprising:

receiving the data at the virtualization system.

6. The method of claim 4, wherein the function call comprises a pointer identifying a location where the data is stored.

7. The method of claim 4, wherein the function call comprises a flag that identifies whether a particular pointer of the one or more pointers references conventional file system buffers or whether the particular pointer references a linked list of network memory buffers.

8. The method of claim 1, wherein the one or more pointers are passed to a SCSI target module of the storage operating system.

9. A data storage apparatus, comprising:

a network protocol stack of a storage operating system executing on a storage system, the network protocol stack configured to receive a write request comprising a write command and data to write to a data storage device of the storage system;

a network memory buffer of the storage system configured to store the write request, the network memory buffer referenced by one or more pointers; and

a processor of the storage system configured to execute the write command to write the data to the data storage device in response to passing the one or more pointers that reference the network memory buffer to a virtualization system of the storage operating system.

10. The data storage apparatus of claim 9, further comprising a function call with a pointer identifying a location where the data is stored.

11. The data storage apparatus of claim 10, wherein the function call comprises a flag that identifies whether a particular pointer of the one or more pointers references conventional file system buffers or whether the particular pointer references a linked list of network memory buffers.

12. The data storage apparatus of claim 9, further comprising:

a virtualization system in communication with the storage operating system; and

at least one storage device of the storage system in communication with the virtualization system.

13. The data storage apparatus of claim 9, wherein the one or more pointers are passed to a SCSI target module of the storage operating system.

14. A computer readable medium containing executable program instructions executed by a processor, comprising:

program instructions that receive a write request at a network protocol stack of a storage operating system executing on a storage system, the write request comprising a write command and data to write to a data storage device of the storage system;

program instructions that store the write request into a network memory buffer of the storage system, the network memory buffer referenced by one or more pointers; and

program instructions that pass the one or more pointers that reference the network memory buffer to a virtualization system of the storage operating system, the virtualization system processing the write command to write the data to the data storage device.

15. A system for storing data, comprising:

means for receiving a write request at a network protocol stack of a storage operating system executing on a storage system, the write request comprising a write command and data to write to a data storage device of the storage system;

means for storing the write request into a network memory buffer of the storage system, the network memory buffer referenced by one or more pointers; and

means for passing the one or more pointers that reference the network memory buffer to a virtualization system of the storage operating system, the virtualization system processing the write command to write the data to the data storage device.

16. The system of claim 15, further comprising:

means for identifying a location where the data is stored by a pointer of a function call.

17. A storage system, comprising:

a network adapter and a network protocol stack of a storage operating system executing on the storage system configured to cooperate to receive a write operation and to write data from the write operation into a memory buffer of the storage system, the write operation configured to utilize a block based protocol, and wherein the network memory buffer is referenced by one or more pointers; and

a processor of the storage system configured to execute a storage operating system, the storage operating system configured to separate header information from the data stored within the memory buffer, the storage operating system further configured to pass the one or more pointers to a virtualization system of the storage operating system, the virtualization system configured to process the write operation utilizing a same memory location where the data was deposited by the network protocol module within the memory buffer.

18. The storage system of claim 17, wherein the protocol module is a Transport Control Protocol/Internet Protocol module of the virtualization system.

19. The system of claim 17, wherein the storage operating system is further configured to free the memory buffer after completing the write operation.

20. The system of claim 17, wherein the memory buffer is configured as a backing store for a file system of the storage operating system to service read requests for the data.

21. The system of claim 17, wherein the block based protocol comprises a Small Computer Systems Interface protocol encapsulated in a Transport Control Protocol/Internet Protocol.

22. A computer readable medium containing executable program instructions executed by a processor, comprising:

program instructions that receive a write operation comprising write data at a set of memory buffers of a storage system;

program instructions that separate header information from the write data within the set of memory buffers;

program instructions that pass a set of pointers referencing the set of memory buffers to a virtualization system of the storage system; and

program instructions that process, by the virtualization system, the write operation by utilizing the write data within the set of memory buffers as originally deposited.

23. A method, comprising:

receiving a write request comprising a write command and data to write to a data storage device of a storage system;

storing the write request into a network memory buffer of the storage system, the network memory buffer referenced by one or more pointers;

receiving the one or more pointers referencing the network memory buffer by a virtualization system of the storage system; and

processing, by the virtualization system, the write command to write the data to the data storage device using the one or more pointers that reference the data in the network memory buffer as originally deposited.

24. The method of claim 23, further comprising:

passing the one or more pointers to a target module of a storage operating system executing on the storage system.

25. The method of claim 24, wherein the target module is a SCSI target module.

26. The method of claim 23, wherein the data storage device is a disk.

27. The method of claim 23, further comprising separating a header of the write request.

28. The method of claim 23, further comprising performing a function call by an iSCSI module of the virtualization system.

29. The method of claim 28, wherein the function call comprises a flag that identifies whether a particular pointer of the one or more pointers references conventional file system buffers or whether the particular pointer references a linked list of network memory buffers.

30. A system, comprising:

a network memory buffer of a storage system configured to store a write request comprising a write command and data to write to a data storage device of the storage system, the network memory buffer referenced by one or more pointers;

a virtualization system of a storage operating system executing on the storage system configured to receive the data; and

a processor of the storage system configured to process the write command to write the data to the data storage device using the one or more pointers that reference the network memory buffer.

31. The system of claim 30, wherein the data storage device is a disk.

32. The system of claim 30, further comprising a function call configured to pass the data to a target module of the storage operating system.

33. The system of claim 32, wherein the function call is performed by an iSCSI module of the virtualization system.

34. The system of claim 32, wherein the function call comprises a flag that identifies whether a particular pointer of the one or more pointers references conventional file system buffers or whether the particular pointer references a linked list of network memory buffers.

35. The system of claim 30, further comprising a SCSI target module of the storage operating system is configured to receive the one or more pointers to process the write command.

36. A computer readable medium containing executable program instructions executed by a processor, comprising:

program instructions that receive a write request comprising a write command and data to write to a data storage device of a storage system, wherein a network memory buffer of the storage system is referenced by one or more pointers;

program instructions that store the write request into the network memory buffer;

program instructions that receive, from a network protocol stack of the storage system, the one or more pointers referencing the network memory buffer by a virtualization system of the storage system; and

program instructions that process, by the virtualization system, the write command to write the data to the data storage device using the one or more pointers that reference the data in the network memory buffer as originally deposited.