Managing updates to multiple sets of metadata pertaining to a memory

Patent metadata

Field	Value
Publication number	US-9715519-B2
Application number	US-201313840418-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Mar 15, 2013
Publication date	Jul 25, 2017
Grant date	Jul 25, 2017

Abstract

Apparatuses, systems, and methods are disclosed for managing multiple sets of metadata. A method includes maintaining a first set of metadata on a volatile recording medium and a second set of metadata on a non-volatile recording medium. The first and second sets of metadata are associated with one or more logical addresses for data stored on the non-volatile recording medium. The first and second sets of metadata relate to a state of the data. A method includes updating the second set of metadata in response to a first operation performed on the data. The second set may be updated based on the first operation. A method includes updating the first set of metadata in response to a subsequent operation performed on the data. The first set may be updated based on the first operation.

First claim

What is claimed is:

1. A method comprising:
executing requests to write data on a non-volatile recording medium, by
storing data segments at respective storage locations of the non-volatile recording medium,
maintaining a first set of metadata on a volatile recording medium, the first set of metadata associating logical addresses with respective storage locations of stored data segments corresponding to the logical addresses on the non-volatile recording medium and indicating a state of the stored data segments, and
maintaining a second set of metadata on the non-volatile recording medium, the second set of metadata associating storage locations of the non-volatile recording medium with respective stored data segments corresponding to the logical addresses and indicating a state of the stored data segments;

updating the second set of metadata in response to a first operation performed on the stored data segments, including a particular stored data segment, wherein the second set of metadata is updated to indicate a state of the particular stored data segment that differs from a state of the particular stored data segment indicated by the first set of metadata, the first set of metadata and the second set of metadata associating the particular stored data segment with a same logical address and a same storage location on the non-volatile recording medium; and
updating the first set of metadata in response to a subsequent operation performed on the stored data segments, wherein the first set of metadata is updated based on the first operation.

2. The method of claim 1 , further comprising:
receiving a request to initiate the subsequent operation;
checking the first set of metadata for a positive indicator that a data segment corresponding to a logical address specified in the second operation and stored at a specified storage location on the non-volatile recording medium is in a designated state in response to receiving the request to initiate the second operation; and
reading a portion of the second set of metadata corresponding to the specified storage location in response to detecting the positive indicator in the first set of metadata indicating that the data segment corresponding to the specified logical address stored at the specified storage location is in the designated state.

3. The method of claim 1 , wherein the second set of metadata is updated without restricting access to the first set of metadata.

4. The method of claim 1 , wherein updating the first set of metadata based on the first operation comprises setting an indicator pertaining to the state of the particular stored data segment in the first set of metadata based, at least in part, on an indication of the state of the particular stored data segment in the second set of metadata.

5. The method of claim 1 , wherein the first set of metadata comprises first entries configured to map logical addresses to storage locations on the non-volatile recording medium of the stored data segments corresponding to the logical addresses, and wherein the second set of metadata comprises a plurality of second entries representing storage locations of the stored data segments on the non-volatile recording medium.

6. The method of claim 5 , wherein one of the first entries of the first set of metadata corresponds to a plurality of second entries of the second set of metadata.

7. The method of claim 5 , wherein a selected first entry corresponds to the logical address associated with the particular stored data segment and comprises an indicator specifying a state of the particular stored data segment, and wherein updating the first set of metadata based on the first operation comprises modifying the indicator of the selected first entry for consistency with the state of the particular stored data segment indicated by the second set of metadata.

8. The method of claim 7 , wherein the indicator comprises one or more of a validity indicator, a dirty data indicator, a frequency indicator, a user indicator, a priority indicator, and a quality-of-service indicator.

9. The method of claim 5 , wherein the plurality of first entries are indexed by logical addresses, and wherein the second entries are indexed according to an order the data segments were stored on the storage locations represented by the respective second entries.

10. The method of claim 1 , wherein the subsequent operation comprises one of a read operation, a write operation, a destage operation, a storage capacity recovery operation, and a background scan process.

11. A non-transitory computer-readable storage medium storing code executable by a processor to perform operations, comprising:
storing data segments at respective physical storage addresses of a solid-state storage medium, wherein storing the data segments further comprises,
maintaining a first set of metadata, the first set of metadata associating logical identifiers of the stored data segments to respective physical storage addresses of the stored data segments on the solid-state storage medium and indicating a state of the respective stored data segments,
maintaining a second set of metadata, the second set of metadata associating respective physical storage addresses with the stored data segments of the logical identifiers and indicating a state of the respective stored data segments,
wherein the first set of metadata and the second set of metadata associate a particular stored data segment with a same logical identifier and a same physical storage address, and

updating the second set of metadata based on a first storage operation pertaining to the non-volatile storage medium, wherein a state of the particular stored data segment indicated by the second set of metadata differs from a state of the particular stored data segment indicated by the first set of metadata; and
updating the first set of metadata in response to a second storage operation pertaining to the non-volatile storage medium subsequent to the first storage operation, wherein the state of the particular stored data segment indicated by the first set of metadata corresponds to the state of the particular stored data segment indicated by the second set of metadata.

12. The non-transitory computer-readable storage medium of claim 11 , wherein the first storage operation comprises destaging the particular stored data segment to a backing store, and wherein the second set of metadata is updated to change the state of the particular stored data segment indicated by the second set of metadata from dirty to clean in response to destaging the particular stored data segment.

13. The non-transitory computer-readable storage medium of claim 12 , wherein the first set of metadata is updated to change the state of the particular stored data segment indicated by the first set of metadata from dirty to clean in response to the second storage operation.

14. The non-transitory computer-readable storage medium of claim 11 , wherein the second set of metadata is updated to indicate that the particular stored data segment is invalid in response to the first storage operation and while the first set of metadata indicates that the particular stored data segment is valid, and wherein the first set of metadata is updated to indicate that the particular stored data segment is invalid in response to the second storage operation subsequent to the first storage operation.

15. The non-transitory computer-readable storage medium of claim 11 , wherein the first set of metadata is accessible while the second set of metadata is updated, and wherein access to at least a portion of the first set of metadata is lo

Assignees

• Sandisk Technologies Llc

Inventors

• Atkisson David

Classifications

• G06F16/2365 Primary

  Ensuring data consistency and integrity · CPC title

• G06F12/0246

  in block erasable memory, e.g. flash memory · CPC title

• G06F2212/7207

  management of metadata or control data · CPC title

• G06F17/30371 Primary

  Physics · mapped topic