SYSTEMS AND METHODS FOR STORAGE METADATA MANAGEMENT

• US 20140344507A1
• Filed: 04/15/2014
• Published: 11/20/2014
• Est. Priority Date: 04/16/2013
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Fusion-IO Incorporated (Western Digital Corporation)
• Inventors: Piggin, Nick, Talagala, Nisha, Koundinya, Santhosh
• Granted Patent: US 10,558,561 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 2212/7207 management of metadata or control data
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0667 at data level, e.g. file, record or object virtualisation
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

A storage layer may be configured to over-provision logical storage resources to objects. The storage layer may provision the resources in response to, inter alia, a request to open and/or create a zero-length file. The storage layer may be further configured to store data of the objects in a contextual format configured to associate the data with respective logical identifiers. The storage layer may determine an actual, storage size of the object based on the associations stored on the stored associations. Storage clients may rely on the storage layer to determine the size of the object and, as such, may defer and/or eliminate updates to persistent metadata.

Claims

1. A method, comprising:

reserving logical identifiers of a logical address space corresponding to a non-volatile storage device for an object, wherein a storage capacity of the reserved logical identifiers exceeds a capacity requirement of the object;

storing data of the object on the non-volatile storage device in a format configured to bind the stored data to respective logical identifiers reserved for the object; and

identifying logical identifiers of the logical identifiers reserved for the object that are bound to data of the object stored on the non-volatile storage device.

2. The method of claim 1, wherein the object is a file system object, and wherein the logical identifiers are reserved for the file system object in response to one of:

a request to open a file, a request to open a zero-size file, a request to open a zero-length file, and a request to open an empty file.

3. The method of claim 1, further comprising determining a physical occupancy of the object on the non-volatile storage device by use of metadata stored with data of the object on the non-volatile storage device.

4. The method of claim 3, wherein the metadata comprises a persistent trim note configured to invalidate at least a portion of the data of the object stored on the non-volatile storage device.

5. The method of claim 1, further comprising determining a physical storage size of the object on the non-volatile storage device based on a number of the identified logical identifiers reserved for the object that are bound to data of the object stored on the non-volatile storage device.

6. The method of claim 1, further comprising determining a size of the object based on a physical occupancy of the logical identifiers reserved for the object on the non-volatile storage device.

7. The method of claim 1, further comprising determining a size of the object based on an identified range of logical identifiers reserved for the object, wherein the identified range comprises logical identifiers that are assigned to storage addresses of the non-volatile storage device comprising data of the object, wherein the identified range of logical identifiers comprises one or more logical identifiers that are not assigned to storage addresses of the non-volatile storage device.

8. The method of claim 1, further comprising identifying the logical identifiers reserved for the object that are bound to data of the object stored on the non-volatile storage device to a file system for use in reconstructing a file system data structure.

9. The method of claim 1, further comprising deferring an update to a persistent file system data structure pertaining to the object in response to storing the data of the object on the non-volatile storage device.

10. The method of claim 1, further comprising appending one or more packets comprising data of the object to a storage log on the non-volatile storage device, the packets comprising persistent metadata configured to associate data of the packets with respective logical identifiers.

11. The method of claim 1, wherein storing the data of the object comprises storing a data segment of the object with metadata configured to bind the data segment to one of the reserved logical identifiers in one of an atomic write operation on the non-volatile storage device, and a single write operation on the non-volatile storage device.

12. An apparatus, comprising:

an allocation module configured to designate logical block addresses of a logical address space of a non-volatile storage device for use by an entity, wherein a storage capacity represented by the designated logical block addresses exceeds a size of the entity; and

a storage layer configured to store data of the entity on respective storage locations of the non-volatile storage device with metadata configured to associate the data with respective logical block addresses designated for use by the entity; and

wherein the storage layer is configured to indicate physical storage resources in use by a subset of the designated logical block addresses to reference data of the entity.

13. The apparatus of claim 12, further comprising a reconstruction module configured to determine the physical storage resources in use by the entity based on a number of storage locations of the non-volatile storage device comprising data of the entity.

14. The apparatus of claim 12, further comprising a reconstruction module configured to identify the subset of the designated logical block addresses by accessing data packets comprising data of the entity stored on the non-volatile storage device.

15. The apparatus of claim 12, further comprising a reconstruction module configured to reconstruct a forward map comprising entries configured to bind logical identifiers designated for use by the entity to storage addresses of the non-volatile storage device by use of the metadata stored with the data of the entity on the non-volatile storage device.

16. The apparatus of claim 12, wherein a file system is configured to update persistent file system metadata pertaining to the entity based on the physical storage resources in use by the subset of the designated logical block addresses to reference data of the entity indicated by the storage layer.

17. The apparatus of claim 12, wherein the storage layer is configured to store the data of the entity in response to one or more storage requests of a storage client, and wherein the storage client is configured to defer an update to persistent metadata pertaining to the entity in response to completion of the one or more storage requests.

18. The apparatus of claim 17, wherein the storage client comprises one of:

a file system, an operating system, and a database.

19. The apparatus of claim 12, wherein the allocation module is configured to maintain a sparse logical address space for the non-volatile storage device, and wherein a logical capacity of the logical address space exceeds a physical storage capacity of the non-volatile storage device.

20. The apparatus of claim 12, wherein the entity is a file, and wherein the allocation module is configured to designate logical block addresses for the file in response to a request pertaining to a zero-length file.

21. The apparatus of claim 12, wherein the allocation module is configured to select the designated logical block addresses from one of a plurality of allocation regions of a logical address space of the non-volatile storage device, the allocation regions having different respective allocation granularities.

22. A system, comprising:

an allocation module configured to reserve identifiers of a logical address space of a non-volatile storage medium for a file, wherein a storage capacity corresponding to the reserved identifiers exceeds a storage requirement of the file;

a storage layer configured store metadata on the non-volatile storage medium, the metadata configured to tie data of the file stored on the non-volatile medium with respective identifiers reserved to the file; and

a file system configured to restore file system metadata pertaining to the file based on a physical storage occupancy of the reserved identifiers determined by the storage layer.

23. The system of claim 22, further comprising a reconstruction module configured to generate a forward map comprising ties between one or more of the reserved identifiers and data of the file stored on the non-volatile storage medium by way of the metadata stored on the non-volatile storage medium.