Maintaining versions of data in solid state memory

• US 9,582,511 B2
• Filed: 09/08/2016
• Issued: 02/28/2017
• Est. Priority Date: 06/12/2012
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kandiraju, Gokul B., Franke, Hubertus, Craft, David
• Primary Examiner(s): Peugh, Brian
• Assistant Examiner(s): CHAN, TRACY C
• Application Number:
  US15/259,169
• Publication Number:
  US 20160378775A1
• Time in Patent Office: 173 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/10 Address translation
• CPC Class Codes: G06F 12/1009 using page tables, e.g. page table structures
• CPC Class Codes: G06F 16/128 Details of file system snapshots on the file-level, e.g. snapshot creation, administration, deletion use of snapshots for error detection or correction G06F11/14, G06F11/16
• CPC Class Codes: G06F 16/1873 Versioning file systems, temporal file systems, e.g. file system supporting different historic versions of files
• CPC Class Codes: G06F 2212/1008 Correctness of operation, e.g. memory ordering
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/202 Non-volatile memory
• CPC Class Codes: G06F 2212/2022 Flash memory
• CPC Class Codes: G06F 2212/65 Details of virtual memory and virtual address translation
• CPC Class Codes: G06F 2212/657 Virtual address space management
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 2212/7209 Validity control, e.g. using flags, time stamps or sequence numbers
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0655 Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0679 : Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G06F 3/0688 : Non-volatile semiconductor memory arrays
• CPC Class Codes: G11C 16/10 : Programming or data input circuits
• CPC Class Codes: G11C 16/26 : Sensing or reading circuits; Data output circuits

Abstract

Various embodiments are directed to maintaining versions of data within a solid state memory. At least one request to write at least one dataset to a logical page of a solid state memory is received from a file system. At least one physical page in a data block of the solid state memory associated with the logical page is identified. A processor stores the dataset in the at least one physical page. At least one data versioning tag is associated with the at least one dataset in a data structure associated with the logical page. The data versioning tag identifies the at least one dataset as a given version of the logical page. The at least one dataset is maintained as accessible from the at least one physical page irrespective of subsequent write operations to the logical page in response to associating the at least one data versioning tag.

Claims

1. A method for managing data in a solid state memory supporting data versioning, the method comprising:

receiving, from a file system, at least one request to perform a snapshot operation, the at least one request comprising a group identifier indicating a group of logical pages from a plurality of groups of a solid state memory on which the snapshot operation is to be performed, and an identifier identifying at least one logical page within the group of logical pages on which the snapshot operation is to be performed;

identifying a data structure associated with the at least one logical page based on at least the group identifier;

identifying, based on the identifier, a set of information within the data structure associated with the at least one logical page;

identifying, based on the set of information, a physical page associated with the at least one logical page comprising a dataset representing a given version of the at least one logical page, wherein the given version is indicated by the at least one request; and

setting a flag within the physical page, wherein the flag prevents garbage collection operations from being performed on the physical page.

2. The method of claim 1, wherein the at least one request comprises a version identifier identifying at least one version of the dataset associated with the at least one logical page on which the snapshot operation is to be performed.

3. The method of claim 2, wherein identifying the physical page further comprises

determining that the version identifier is null;

and

identifying the physical page associated with the at least one logical page comprising a dataset representing a most recent version of the at least one logical page.

4. The method of claim 2, wherein identifying the physical page further comprises

determining that the version identifier comprises a value identifying the given version of the at least one logical page;

identifying, based on the set of information, the physical page of the at least one logical page comprising a dataset associated with a particular version identifier matching the version identifier in the at least one request performing the snapshot operation.

5. The method of claim 1, wherein the at least one request consists of only the group identifier, the identifier identifying the at least one logical page, and a version identifier identifying at least one version of the dataset associated with the at least one logical page on which the snapshot operation is to be performed.

6. The method of claim 1, wherein the group identifier identifies one of data blocks, indirect blocks, and inode blocks.

7. A computer program product for managing data in a solid state memory supporting data versioning, the computer program product comprising a non-transitory storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method, the method comprising:

receiving, from a file system, at least one request to perform a snapshot operation, the at least one snapshot request comprising a group identifier indicating a group of logical pages from a plurality of groups of a solid state memory on which the snapshot operation is to be performed, and an identifier identifying at least one logical page within the group of logical pages on which the snapshot operation is to be performed;

identifying a data structure associated with the at least one logical page based on at least the group identifier;

identifying, based on the identifier, a set of information within the data structure associated with the at least one logical page;

identifying, based on the set of information, a physical page associated with the at least one logical page comprising a dataset representing a given version of the at least one logical page, wherein the given version is indicated by the at least one request; and

setting a flag within the physical page, wherein the flag prevents garbage collection operations from being performed on the physical page.

8. The computer program product of claim 7, wherein the at least one request comprises a version identifier identifying at least one version of the dataset associated with the at least one logical page on which the snapshot operation is to be performed.

9. The computer program product of claim 8, wherein identifying the physical page further comprises

determining that the version identifier is null;

and

identifying the physical page associated with the at least one logical page comprising a dataset representing a most recent version of the at least one logical page.

10. The computer program product of claim 8, wherein identifying the physical page further comprises

determining that the version identifier comprises a value identifying the given version of the at least one logical page;

identifying, based on the set of information, the physical page of the at least one logical page comprising a dataset associated with a particular version identifier matching the version identifier in the at least one request performing the snapshot operation.

11. The computer program product of claim 7, wherein the at least one request consists of only the group identifier, the identifier identifying the at least one logical page, and a version identifier identifying at least one version of the dataset associated with the at least one logical page on which the snapshot operation is to be performed.

12. The computer program product of claim 7, wherein the group identifier identifies one of data blocks, indirect blocks, and inode blocks.

17. The method of claim 12, wherein the group identifier identifies one of data blocks, indirect blocks, and inode blocks.

13. A method for managing data in a solid state memory supporting data versioning, the method comprising:

receiving, from a file system, at least one request to perform a rollback operation,

the at least one request comprising at least a group identifier indicating a group of logical pages from a plurality of groups of a solid state memory on which the rollback operation is to be performed, an identifier identifying at least one logical page within the group of logical pages on which the rollback operation is to be performed;

identifying a data structure associated with the at least one logical page based on at least the group identifier;

identifying, based on the identifier, a set of information within the data structure associated with the at least one logical page;

identifying, based on the set of information, a physical page of the at least one logical page associated with a previous version of the at least one logical page; and

performing the rollback operation on the logical page by updating a logical-to-physical translation table entry for the at least one logical page to point to the physical page that has been identified.

14. The method of claim 13, wherein the at least one request further comprises a version identifier identifying a previous version of the at least one logical page that the at least one logical page is to be rolled back to.

15. The method of claim 14, wherein identifying the physical page further comprises

identifying, based on the set of information, a physical page of the at least one logical page associated with a version identifier matching the version identifier within the rollback request.

16. The method of claim 13, further comprising:

updating the data structure to move an entry for the physical page to a beginning of the data structure.