System and method for creation/deletion of linear block address table entries for direct I/O

• US 7,464,189 B2
• Filed: 05/23/2005
• Issued: 12/09/2008
• 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
• Primary Examiner(s): Dollinger; Tonia L. M.
• Assistant Examiner(s): Dews; Brooke J
• Application Number:
  US11/135,539
• Publication Number:
  US 20060265521A1
• Time in Patent Office: 1,296 Days
• Field of Search: 710/3, 710/22, 707/204
• 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

A method 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 is provided. In one aspect of the method, 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 method, in an input/output (I/O) adapter, comprising:

receiving, 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;

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

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

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

deleting an LBA table entry corresponding to the second resources from the LBA table, wherein deleting the LBA table entry includes;

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

3. The method of claim 1, further comprising:

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

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

4. The method of claim 1, wherein deleting an LBA table entry corresponding to the second resources includes using a memory management interface of the I/O adapter to delete the LBA table entry.

5. The method of claim 1, 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

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

6. The method 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 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.