FILE SYSTEM HINTING

• US 20130262533A1
• Filed: 03/29/2012
• Published: 10/03/2013
• Est. Priority Date: 03/29/2012
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: LSI Corporation (Broadcom, Inc.)
• Inventors: Mitra, Rebanta, Hiregoudar, Mahesh Shivanagouda, Banavara Ramaswamy, Anantha Keerthi
• Granted Patent: US 8,825,724 B2
• Time in Patent Office: Days
• US Class Current: 707/822
• CPC Class Codes: G06F 12/0862 with prefetch
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 12/126 with special data handling, e.g. priority of data or instructions, handling errors or pinning
• CPC Class Codes: G06F 16/172 Caching, prefetching or hoarding of files
• CPC Class Codes: G06F 2212/1024 Latency reduction
• CPC Class Codes: G06F 2212/1041 Resource optimization
• CPC Class Codes: G06F 2212/6028 Prefetching based on hints or prefetch instructions

Abstract

A method for generating and communicating file system hints. The method may include receiving an I/O request from a file system layer and checking the I/O request for file system contextual information. The method may also include accessing the file system layer to determine attributes of the file system contextual information and receiving the attributes of the file system contextual information from the file system layer. The method may further include analyzing attributes of the file system contextual information and generating a hint based upon analyzing the attributes of the file system contextual information. The method may include a mechanism to provide weight-age of data passed from the application. The hint may be associated with the I/O request, and the hint may comprise hotness information to increase efficiency of data accessibility at a lower level storage tier. The method may include sending the hint to the lower level storage tier.

Claims

1. A method for generating and communicating file system hints, the method comprising:

receiving an I/O request from a file system layer;

checking the I/O request for file system contextual information;

accessing the file system layer to determine attributes of the file system contextual information;

receiving the attributes of the file system contextual information from the file system layer;

analyzing the attributes of the file system contextual information;

generating at least one hint based upon analyzing the attributes of the file system contextual information, wherein said at least one hint indicates a relative importance of I/O request data associated with the hint and is configured to be used to direct relatively more important I/O request data to be stored in a relatively faster storage medium; and

sending the at least one hint to a lower level storage tier.

2. The method of claim 1, wherein the file system contextual information comprises at least one of file system metadata, a file system access pattern, a file system inode (index node), a file system vnode (virtual index node), a file system super block, a transaction log of a journaling file system, a group descriptor table, a block bitmap, an inode bitmap, an inode table, or an inode metafile.

3. The method of claim 1, wherein the file system contextual information comprises at least a file system super block.

4. The method of claim 1, wherein the file system contextual information comprises at least file system metadata.

5. The method of claim 1, wherein the file system contextual information comprises at least one of a file system inode (index node) or a file system vnode (virtual index node).

6. The method of claim 5, wherein checking the I/O request for file system contextual information further comprises:

checking at least one of a flag, a state, or a field of at least one block of the I/O request for file system contextual information.

7. The method of claim 5, wherein checking the I/O request for file system contextual information further comprises:

checking whether at least one block of the I/O request includes a super block.

8. The method of claim 5, wherein checking the I/O request for file system contextual information further comprises:

checking whether the file system inode or the file system vnode is a metainode (meta-index node) or a (meta-virtual index node) metavnode.

9. The method of claim 1, wherein receiving an I/O request from the file system layer further comprises:

receiving an I/O request from a file system inode (index node) cache or from a buffer cache of the file system layer, wherein receiving occurs between the file system layer and a block layer.

10. The method of claim 1, further comprising:

storing the at least one hint against at least one logical block address associated with the I/O request in a hash table.

11. The method of claim 1, wherein the lower level storage tier comprises at least one of a lower level storage driver, a lower level storage controller, or a lower level storage system.

12. The method of claim 1, wherein sending the at least one hint to the lower level storage tier further comprises:

attaching the at least one hint to at least one unused field of at east one block of the I/O request; and

sending the I/O request to the lower level storage tier.

13. The method of claim 1, further comprising:

sending the I/O request to a lower level storage tier;

receiving a request for the at least one hint from the lower level storage tier; and

wherein sending the at least one hint to a lower level storage tier further comprises;

sending the at least one hint to a lower level storage tier upon receiving the request for the at least one hint from the lower level storage tier.

14. A device configured to attach to a system topology for generating and communicating file system hints, the device comprising:

a filter driver, the filter driver configured to communicate with a file system layer, a block layer, and lower level storage tier of the system topology, said filter driver comprising a hint engine and a communication component, said filter driver further configured at least to;

receive an I/O request from the file system layer;

check the I/O request for file system contextual information;

access the file system layer to determine attributes of the file system contextual information;

receive the attributes of the file system contextual information from the file system layer;

analyze the attributes of the file system contextual information;

generate at least one hint based upon analyzing the attributes of the file system contextual information, wherein said at least one hint indicates a relative importance of I/O request data associated with the hint and is configured to be used to direct relatively more important I/O request data to be stored in a relatively faster storage medium; and

send the at least one hint to the lower level storage tier.

15. The device of claim 14, wherein the file system contextual information comprises at least one of a file system inode (index node) or a file system vnode (virtual index node), and wherein the filter driver is further configured to:

check at least one of a flag, a state, or a field of at least one block of the I/O request for file system contextual information;

check whether the at least one block of the I/O request includes a super block; and

check whether the file system inode or the file system vnode is a metainode (meta-index node) or a (meta-virtual index node) metavnode.

16. The device of claim 14, wherein the filter driver is further configured to:

attach the at least one hint to at least one unused field of at least one block of the I/O request; and

send the I/O request to the lower level storage tier with the at least one hint attached.

17. The device of claim 14, wherein the lower level storage tier comprises at least one of a lower level storage driver, a lower level storage controller, or a lower level storage system.

18. A non-transitory computer-readable medium embodying computer code for causing a computing device to perform a method for generating and communicating file system hints, the computer code causing the computing device to execute:

receiving an I/O request from a file system layer;

checking the I/O request for file system contextual information;

accessing the file system layer to determine attributes of the file system contextual information;

receiving the attributes of the file system contextual information from the file system layer;

analyzing the attributes of the file system contextual information;

generating at least one hint based upon analyzing the attributes of the file system contextual information, wherein said at least one hint indicates a relative importance of I/O request data associated with the hint and is configured to be used to direct relatively more important I/O request data to be stored in a relatively faster storage medium; and

sending the hint to a lower level storage tier.

19. The non-transitory computer-readable medium embodying computer code of claim 18, wherein the file system contextual information comprises at least one of a file system inode (index node) or a file system vnode (virtual index node), and wherein checking the I/O request for file system contextual information further comprises:

checking at least one of a flag, a state, or a field of at least one block of the I/O request for file system contextual information;

checking whether the at least one block of the I/O request includes a super block; and

checking whether the file system inode or the file system vnode is a metainode (meta-index node) or a (meta-virtual index node) metavnode.

20. The non-transitory computer-readable medium embodying computer code of claim 18, wherein sending the at least one hint to the lower level storage tier further comprises:

attaching the at least one hint to at least one unused field of at least one block of the I/O request; and

sending the I/O request to the lower level storage tier.