Mechanisms for creation/deletion of linear block address table entries for direct I/O

• US 7,849,228 B2
• Filed: 11/12/2008
• Issued: 12/07/2010
• Est. Priority Date: 05/23/2005
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Lee; Chun-Kuan
• Assistant Examiner(s): Dews; Brooke J
• Application Number:
  US12/269,419
• Publication Number:
  US 20090064163A1
• Time in Patent Office: 755 Days
• Field of Search: 710/3
• US Class Current: 710/3
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 12/145 the protection being virtual, e.g. for virtual blocks or segments before a translation mechanism
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• 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 mechanisms that enable 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 creation and deletion operations for creating and deleting allocations of linear block addresses of a physical storage device to application instances. For creation, it is determined if there are sufficient available resources for creation of the allocation. For deletion, it is determined if there are any I/O transactions active on the allocation before performing the deletion. Allocation may be performed only if there are sufficient available resources and deletion may be performed only if there are no active I/O transactions on the allocation being deleted.

Claims

1. A computer program product comprising a computer recordable medium having a computer readable program stored thereon, 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 creation of a resource allocation for direct linear block address (LBA) based input/output (I/O) between the application instance and a physical storage device;

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

return results of the creation of the resource allocation to the application instance;

receive, from the application instance, a second user space operation requesting de-allocation of second resources;

and delete an LBA table entry corresponding to the second resources from the LBA table, wherein the computer readable program causes the computing device to delete the LBA table entry by;

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

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

2. The computer program product of claim 1, wherein the computer readable program causes the computing device to create the resource allocation in the LBA table entry by using a memory management interface of the I/O adapter to create the LBA table entry.

3. The computer program product of claim 1, wherein the computer readable program further causes the computing device to:

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

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

4. The computer program product of claim 1, wherein the computer readable program causes the computing device to delete an LBA table entry corresponding to the second resources by using a memory management interface of the I/O adapter to delete the LBA table entry.

5. The computer program product of claim 1, 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

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

6. The computer program product of claim 5, wherein the quiescent point is a point at which no I/O transactions are active on the LBA table entry.

7. The computer program product 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.

8. 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 running on the host system, a user space operation requesting creation of a resource allocation for direct linear block address (LBA) based input/output (I/O) between the application instance and the physical storage device;

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

and returns results of the creation of the resource allocation to the application instance;

receives, from the application instance, a second user space operation requesting de-allocation of second resources;

and deletes an LBA table entry corresponding to the second resources from the LBA table, wherein the host system deletes the LBA table entry by;

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

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

9. The data processing system of claim 8, wherein the host system receives, from the application instance, a second user space operation requesting de-allocation of second resources and deletes an LBA table entry corresponding to the second resources from the LBA table.

10. The data processing system of claim 8, wherein the host system creates the resource allocation in the LBA table entry by using a memory management interface of the I/O adapter to create the LBA table entry.

11. The data processing system of claim 8, wherein the host system:

determines if sufficient resources are available to create the resource allocation; and

returns an error message if there are not sufficient resources available to create the resource allocation.

12. The data processing system of claim 8, wherein the host system deletes an LBA table entry corresponding to the second resources by using a memory management interface of the I/O adapter to delete the LBA table entry.

13. The data processing system of claim 8, wherein the host system:

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

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

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

14. The data processing system of claim 13, wherein the quiescent point is a point at which no I/O transactions are active on the LBA table entry.

15. The data processing system of claim 8, 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.