System and method for query/modification of linear block address table entries for direct I/O

• US 20060265522A1
• Filed: 05/23/2005
• Published: 11/23/2006
• Est. Priority Date: 05/23/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Recio, Renato John, Vega, Madeline, Boyd, William Todd, Mena, Agustin III, Hufferd, John Lewis
• Granted Patent: US 7,502,871 B2
• Time in Patent Office: Days
• US Class Current: 710/9
• CPC Class Codes: G06F 21/85 interconnection devices, e.g. bus-connected or in-line devices
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0637 Permissions
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

The present invention provides a system, method, and computer program product that enables application instances to pass block mode storage requests directly to a physical I/O adapter without run-time involvement from the local operating system or hypervisor. In one aspect of the present invention, a mechanism is provided for handling user space query and modification operations for querying and modifying attributes of allocations of linear block addresses of a physical storage device. For modification, it is determined if there are sufficient available resources for the modification of the allocation. In addition, it is determined if there are any I/O transactions active on the allocation before performing the modification. Modification of the attributes of the allocation may be performed only if there are sufficient available resources and only if there are no active I/O transactions on the allocation being modified.

Claims

1. A method, in an input/output (I/O) adapter, comprising:

receiving, from an application instance, a user space operation requesting modification of a resource allocation for direct linear block address (LBA) based input/output (I/O) between the application instance and a physical storage device;

modifying the resource allocation in a LBA table entry, of an LBA table, associated with the I/O adapter and the application instance; and

returning results of the modification of the resource allocation to the application instance.

2. The method of claim 1, wherein modifying the resource allocation in the LBA table entry includes using a memory management interface of the I/O adapter to modify the LBA table entry.

3. The method of claim 1, further comprising:

determining if sufficient resources are available to modify the resource allocation; and

returning an error message if there are not sufficient resources available to modify the resource allocation.

4. The method of claim 1, further comprising:

receiving, from the application instance, a second user space operation requesting a query of attribute information of the resource allocation; and

retrieving attribute information for the resource allocation from an LBA table entry corresponding to the resource allocation.

5. The method of claim 4, wherein retrieving attribute information for the resource allocation includes using a memory management interface of the I/O adapter to query the LBA table entry.

6. The method of claim 1, further comprising:

determining if an I/O transaction is active on the LBA table entry; and

modifying the LBA table entry only if there are no I/O transactions active on the LBA table entry.

7. The method of claim 6, further comprising:

initiating a timer if there is an I/O transaction active on the LBA table entry;

determining if a quiescent point is reached before the timer times out; and

modifying the LBA table entry only if the quiescent point is reached before the timer times out.

8. The method of claim 7, wherein the quiescent point is a point at which no I/O transactions are active on the LBA table entry.

9. The method of claim 1, wherein the LBA table entry includes a pointer to one or more LBAs of the physical storage device, and wherein the LBA table entry is associated with an adapter protection table entry, in an adapter protection table, which is used by an application instance to access the one or more LBAs of the physical storage device.

10. A computer program product comprising a computer useable medium having a computer readable program, wherein the computer readable program, when executed on computing device, causes the computing device to:

receive, from an application instance, a user space operation requesting modification of a resource allocation for direct linear block address (LBA) based input/output (I/O) between the application instance and a physical storage device;

modify the resource allocation in a LBA table entry, of an LBA table, associated with the I/O adapter and the application instance; and

return results of the modification of the resource allocation to the application instance.

11. The computer program product of claim 10, wherein the computer readable program causes the computing device to modify the resource allocation in the LBA table entry by using a memory management interface of the I/O adapter to modify the LBA table entry.

12. The computer program product of claim 10, wherein the computer readable program further causes the computing device to:

determine if sufficient resources are available to modify the resource allocation; and

return an error message is there are not sufficient resources available to modify the resource allocation.

13. The computer program product of claim 10, wherein the computer readable program further causes the computing device to:

receive, from the application instance, a second user space operation requesting a query of attribute information of the resource allocation; and

retrieve attribute information for the resource allocation from an LBA table entry corresponding to the resource allocation.

14. The computer program product of claim 13, wherein the computer readable program causes the computing device to retrieve attribute information for the resource allocation by using a memory management interface of the I/O adapter to query the LBA table entry.

15. The computer program product of claim 10, wherein the computer readable program further causes the computing device to:

determine if an I/O transaction is active on the LBA table entry; and

modify the LBA table entry only if there are no I/O transactions active on the LBA table entry.

16. The computer program product of claim 15, wherein the computer readable program further causes the computing device to:

initiate a timer if there is an I/O transaction active on the LBA table entry;

determine if a quiescent point is reached before the timer times out; and

modify the LBA table entry only if the quiescent point is reached before the timer times out.

17. The computer program product of claim 16, wherein the quiescent point is a point at which no I/O transactions are active on the LBA table entry.

18. The computer program product of claim 10, wherein the LBA table entry includes a pointer to one or more LBAs of the physical storage device, and wherein the LBA table entry is associated with an adapter protection table entry, in an adapter protection table, which is used by an application instance to access the one or more LBAs of the physical storage device.

19. A data processing system, comprising:

a host system; and

a physical storage device coupled to the host system, wherein the host system;

receives, from an application instance, a user space operation requesting modification of a resource allocation for direct linear block address (LBA) based input/output (I/O) between the application instance and a physical storage device;

modifies the resource allocation in a LBA table entry, of an LBA table, associated with the I/O adapter and the application instance; and

returns results of the modification of the resource allocation to the application instance.

20. The data processing system of claim 19, wherein the host system receives, from the application instance, a second user space operation requesting a query of attribute information of the resource allocation and retrieves attribute information for the resource allocation from an LBA table entry corresponding to the resource allocation.