System and method for supporting atomic writes in a flash translation layer

• US 10,101,930 B2
• Filed: 09/30/2016
• Issued: 10/16/2018
• Est. Priority Date: 11/27/2013
• Status: Active Grant

• Current Assignee: NGD Systems, Inc.
• Original Assignee: NGD Systems, Inc.
• Inventors: Salessi, Nader, Alcantara, Joao
• Primary Examiner(s): Savla, Arpan P.
• Application Number:
  US15/281,902
• Publication Number:
  US 20170017428A1
• Time in Patent Office: 746 Days
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/0292 using tables or multilevel address translation means G06F12/023 takes precedence; address translation in virtual memory systems G06F12/10
• CPC Class Codes: G06F 12/1009 using page tables, e.g. page table structures
• CPC Class Codes: G06F 2212/2022 Flash memory
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

A method for memory-efficient backup of a logical-to-physical (LtoP) table in a storage device having a processor, a volatile memory, and a non-volatile memory, includes retrieving and subsequently processing, by the processor, a plurality of flushed zone segments stored in a first block stripe of the non-volatile memory in an order opposite to an order of storage of the plurality of flushed zone segments in the first block stripe in the non-volatile memory, wherein the processing of the plurality of flushed zone segments includes identifying a retrieved flushed zone segment of the plurality of flushed zone segments differing from all previously retrieved plurality of flushed zone segments, and writing the identified retrieved flushed zone segment of the plurality of flushed zone segments to a second block stripe of the non-volatile memory.

Claims

1. A method for memory-efficient backup of a logical-to-physical (LtoP) table in a storage device comprising a processor, a volatile memory, and a non-volatile memory, the storage device being in communication with a host, the method comprising:

for each flushed zone segment of a plurality of flushed zone segments stored in a first block stripe of the non-volatile memory, retrieving and subsequently processing, by the processor, the flushed zone segment in an order opposite to an order of storage of the plurality of flushed zone segments in the first block stripe in the non-volatile memory, the retrieving and the subsequently processing being performed one flushed zone segment at a time,

wherein each of the plurality of flushed zone segments comprises a header storing a zone number, and two or more of the plurality of flushed zone segments stored in the first block stripe have a same zone number, and

wherein the processing of the plurality of flushed zone segments comprises;

identifying a retrieved flushed zone segment of the plurality of flushed zone segments differing from all previously retrieved plurality of flushed zone segments; and

writing the identified retrieved flushed zone segment of the plurality of flushed zone segments to a second block stripe of the non-volatile memory, and

wherein each flushed zone segment of the plurality of flushed zone segments corresponds to a plurality of logical addresses of the host.

2. The method of claim 1, wherein each of the plurality of flushed zone segments further comprises zone information.

3. The method of claim 1, wherein identifying a retrieved flushed zone segment of the plurality of flushed zone segments comprises:

identifying a retrieved flushed zone segment of the plurality of flushed zone segments having a retrieved zone number differing from zone numbers of all previously retrieved plurality of flushed zone segments.

4. The method of claim 2, wherein zone information comprises a plurality of physical addresses of the LtoP table and an associated plurality of logical addresses of host data previously stored at the non-volatile memory.

5. A storage device configured to efficiently backup a logical-to-physical (LtoP) table in a non-volatile memory, the storage device being in communication with a host, the storage device comprising:

a processor; and

a memory comprising a volatile memory and the non-volatile memory, wherein the memory has stored thereon instructions that, when executed by the processor, cause the processor to perform;

for each flushed zone segment of a plurality of flushed zone segments stored in a first block stripe of the non-volatile memory, retrieving and subsequently processing the flushed zone segment n an order opposite to an order of storage of the plurality of flushed zone segments in the first block stripe in the non-volatile memory, the retrieving and the subsequently processing being performed one flushed zone segment at a time,

wherein each of the plurality of flushed zone segments comprises a header storing a zone number, and two or more of the plurality of flushed zone segments stored in the first block stripe have a same zone number, and

wherein the processing of the plurality of flushed zone segments comprises;

identifying a retrieved flushed zone segment of the plurality of flushed zone segments differing from all previously retrieved plurality of flushed zone segments; and

writing the identified retrieved flushed zone segment of the plurality of flushed zone segments to a second block stripe of the non-volatile memory, and

wherein each flushed zone segment of the plurality of flushed zone segments corresponds to a plurality of logical addresses of the host.

6. The storage device of claim 5, wherein each of the plurality of flushed zone segments further comprises zone information.

7. The storage device of claim 6, wherein zone information comprises a plurality of physical addresses of the LtoP table and an associated plurality of logical addresses of host data previously stored at the non-volatile memory.

8. The storage device of claim 5, wherein identifying a retrieved flushed zone segment of the plurality of flushed zone segments comprises:

identifying a retrieved flushed zone segment of the plurality of flushed zone segments having a retrieved zone number differing from zone numbers of all previously retrieved plurality of flushed zone segments.