End-to-end checksumming for read operations

A method for detecting a data error associated with a data operation comprising:

• issuing a request, by an issuing host, for a data operation in connection with a device;
• determining if said data operation is a read operation having checksumming enabled for a file associated with said read operation;
• forming a data packet that includes a data command requesting data to be read and a checksum value for said data;
• receiving said data packet at a target location;
• sending a single return data packet including said data and said checksum value to said issuing host, wherein a plurality of drivers are used in forming said data packet on said issuing host;
• recording, using a first filter driver, request information in accordance with said read operation associated with a file having checksumming enabled;
• determining, by a second filter driver using said request information, if a received request is for a read operation associated with a file having checksumming enabled;
• if said received request is for a read operation associated with a file having checksumming enabled, forming a data packet to include a special function code indicating that a checksum is to be returned in a single return packet from a data storage system, said single return packet including data associated with said read operation and said checksum, wherein said second filter driver replaces a standard read command with a vendor-defined read command, and said standard read command and said vendor-defined read command are in accordance with a predefined standard, and wherein a file system driver receives said request from said first filter driver, said file system driver being positioned between said first filter driver and said second filter driver in an input/output stack in said issuing host, said request is an original data request;
• issuing, by said file system driver, a plurality of child data requests corresponding to said original data request;
• and
• wherein a request received by said second filter driver includes a first memory descriptor list of physical memory locations associated with said request, and wherein the method further comprises said second filter driver, performing, upon determining that said request is for a read operation associated with a file having checksumming enabled:
• creating a second memory descriptor list and copying said first memory descriptor list to said second memory descriptor list;
• allocating an additional portion of physical memory for holding a checksum value associated with said read operation;
• modifying said second memory descriptor list to include said additional portion for said checksum value;
• and
• including said second memory descriptor list in said request rather than said first memory descriptor list.

A computer program product comprising machine executable code on a computer readable medium that detects a data error associated with a data operation, the computer readable medium comprising:

• machine executable code that issues a request, by an issuing host, for a data operation in connection with a device;
• machine executable code that determines if said data operation is a read operation having checksumming enabled for a file associated with said read operation;
• machine executable code that forms a data packet that includes a data command requesting data to be read and a checksum value for said data;
• machine executable code that receives said data packet at a target location on a data storage system;
• and
• machine executable code that sends a single return data packet including said data and said checksum value from said data storage system to said issuing host.

A computer program product comprising machine executable code on a computer readable medium that detects a data error associated with a data operation, the computer readable medium comprising:

• machine executable code that issues a request, by an issuing host, for a data operation in connection with a device;
• machine executable code that determines if said data operation is a read operation having checksumming enabled for a file associated with said read operation;
• machine executable code that forms a data packet that includes a data command requesting data to be read and a checksum value for said data;
• machine executable code that receives said data packet at a target location;
• machine executable code that sends a single return data packet including said data and said checksum value to said issuing host, wherein a plurality of drivers are used in forming said data packet on said issuing host;
• machine executable code that records, using a first filter driver, request information in accordance with said read operation associated with a file having checksumming enabled;
• machine executable code that determines, by a second filter driver using said request information, if a received request is for a read operation associated with a file having checksumming enabled;
• machine executable code that, if said received request is for a read operation associated with a file having checksumming enabled, forms a data packet to include a special function code indicating that a checksum is to be returned in a single return packet from a data storage system, said single return packet including data associated with said read operation and said checksum, wherein said second filter driver replaces a standard read command with a vendor-defined read command, said standard read command and said vendor-defined read command are in accordance with a predefined standard, a file system driver receives said request from said first filter driver, said file system driver being positioned between said first filter driver and said second filter driver in an input/output stack in said issuing host, said request is an original data request;
• machine executable code that issues, by said file system driver, a plurality of child data requests corresponding to said original data request;
• and
• wherein a request received by said second filter driver includes a first memory descriptor list of physical memory locations associated with said request, and wherein the computer program product further comprises machine executable code causing said second filter driver to perform, upon determining that said request is for a read operation associated with a file having checksumming enabled:
• creating a second memory descriptor list and copying said first memory descriptor list to said second memory descriptor list;
• allocating an additional portion of physical memory for holding a checksum value associated with said read operation;
• modifying said second memory descriptor list to include said additional portion for said checksum value;
• and
• including said second memory descriptor list in said request rather than said first memory descriptor list.