Efficient resource reclamation after deletion of slice from common file

• US 10,511,665 B2
• Filed: 12/12/2017
• Issued: 12/17/2019
• Est. Priority Date: 01/30/2015
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Pure Storage, Inc.
• Inventors: Dhuse, Greg R., Volvovski, Ilya, Kaczmarek, Joseph M., Vossberg, Trevor J.
• Primary Examiner(s): Alphonse, Fritz
• Application Number:
  US15/838,725
• Publication Number:
  US 20180103103A1
• Time in Patent Office: 735 Days
• Field of Search: 714759, 714762, 714760
• CPC Class Codes: H03M 13/09 Error detection only, e.g. using cyclic redundancy check [CRC] codes or single parity bit
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• CPC Class Codes: H03M 13/3761 using code combining, i.e. using combining of codeword portions which may have been transmitted separately, e.g. Digital Fountain codes, Raptor codes or Luby Transform [LT] codes
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

A distributed storage network (DSN) employs one or more distributed storage task execution (DST EX) units for dispersed storage of encoded data slices. A delete-slice request associated with a first encoded data slice is received at a DST EX unit, the encoded data slice is packed into a common file with other encoded data slices, and the common file is stored in a distributed storage (DS) memory included in the DST EX unit. Each encoded data slice packed into the common file is associated with a file offset within the common file. The DST EX unit identifies a file offset of the first encoded data slice within the common file. The DST EX unit releases the portion of the DS memory associated with the particular file offset within the common file to a file system maintained by the DST EX unit.

Claims

1. A method for use in a distributed storage network (DSN) employing one or more distributed storage task execution (DST EX) units for dispersed storage of encoded data slices, the method comprising:

receiving, at a DST EX unit, a delete-slice request associated with a first encoded data slice packed into a common file with other encoded data slices, wherein;

the common file being stored in a distributed storage (DS) memory included in the DST EX unit, and

each encoded data slice packed into the common file is associated with a file offset within the common file;

identifying, by the DST EX unit, a particular file offset within the common file, the particular file offset associated with the first encoded data slice; and

facilitating, by the DST EX unit, releasing a portion of the DS memory to a file system maintained by the DST EX unit, wherein the portion of the DS memory is associated with the particular file offset within the common file.

2. The method of claim 1, wherein facilitating includes:

passing an indication to the file system that the portion of the DS memory associated with the particular file offset within the common file is available.

3. The method of claim 1, wherein facilitating includes:

re-associating file offsets associated with subsequent encoded data slices, the subsequent encoded data slices associated with file offsets, within the common file, subsequent to the particular file offset; and

wherein re-associating the file offsets includes associating the subsequent encoded data slices with a decremented file offset.

4. The method of claim 1, wherein facilitating includes:

issuing a release-memory request to the file system, wherein the release-memory request includes one or more of;

a file name of the common file, a file offset, or an identified portion of the DS memory that corresponds to a storage location of the encoded data slice.

5. The method of claim 1, wherein identifying the particular file offset includes:

performing a lookup within a slice mapping table using a slice name to identify at least one of a filename of the common file, or the particular file offset corresponding to the slice name.

6. The method of claim 1, further comprising:

interpreting the delete-slice request to extract a slice name of the first encoded data slice.

7. The method of claim 1, further comprising:

receiving a write-slice request indicating a new encoded data slice is to be stored by the DST EX unit; and

writing the new encoded data slice into the common file at a file offset associated with the portion of the DS memory that was released.

8. A distributed storage task execution (DST EX) unit comprising:

a processor and associated memory;

a distributed storage (DS) memory coupled to the processor and associated memory, the DS memory configured to store encoded data slices;

a network interface coupled to the processor and associated memory, the network interface configured to receive, from a distributed storage network (DSN), a delete-slice request associated with a first encoded data slice packed into a common file with other encoded data slices, wherein;

the common file is stored in the DS memory, and

each encoded data slice packed into the common file is associated with a file offset within the common file;

the processor and associated memory configured to;

identify a particular file offset within the common file, the particular file offset associated with the first encoded data slice; and

facilitate releasing a portion of the DS memory to a file system maintained by the DST EX unit, wherein the portion of the DS memory is associated with the particular file offset within the common file.

9. The distributed storage task execution (DST EX) unit of claim 8, the processor and associated memory configured to facilitate releasing a portion of the DS memory to a file system by:

facilitate releasing a portion of the DS memory to a file system by passing an indication to the file system that the portion of the DS memory associated with the particular file offset within the common file is available.

10. The distributed storage task execution (DST EX) unit of claim 8, the processor and associated memory further configured to:

re-associate file offsets associated with subsequent encoded data slices, the subsequent encoded data slices associated with file offsets, within the common file, subsequent to the particular file offset; and

wherein re-associating the file offsets includes associating the subsequent encoded data slices with a decremented file offset.

11. The distributed storage task execution (DST EX) unit of claim 8, the processor and associated memory further configured to:

issue a release-memory request to the file system, wherein the release-memory request includes one or more of;

a file name of the common file, a file offset, or an identified portion of the DS memory that corresponds to a storage location of the encoded data slice.

12. The distributed storage task execution (DST EX) unit of claim 8, wherein the processor and associated memory further configured to:

perform a lookup within a slice mapping table using a slice name to identify at least one of a filename of the common file, or the particular file offset corresponding to the slice name.

13. The distributed storage task execution (DST EX) unit of claim 8, the processor and associated memory further configured to:

interpret the delete-slice request to extract a slice name of the first encoded data slice.

14. The distributed storage task execution (DST EX) unit of claim 8, wherein:

the network interface is further configured to receive a write-slice request indicating a new encoded data slice is to be stored by the DST EX unit; and

the processor and associated memory are further configured to write the new encoded data slice into the common file at a file offset associated with the portion of the DS memory that was released.

15. A distributed storage network (DSN) comprising:

a distributed storage task (DST) processing unit;

a DSN memory coupled to the DST processing unit, the DSN memory including a set of distributed storage task execution (DST EX) units used for dispersed storage of encoded data slices, at least one DST EX unit configured to;

receive, from the DST processing unit, a delete-slice request associated with a first encoded data slice packed into a common file with other encoded data slices, wherein;

the common file is stored in a distributed storage (DS) memory included in the at least one DST EX unit, and

each encoded data slice packed into the common file is associated with a file offset within the common file;

identify a particular file offset within the common file, the particular file offset associated with the first encoded data slice; and

facilitate releasing a portion of the DS memory to a file system maintained by the at least one DST EX unit, wherein the portion of the DS memory is associated with the particular file offset within the common file.

16. The distributed storage network (DSN) of claim 15, wherein the at least one DST EX unit is configured to:

pass an indication to the file system that the portion of the DS memory associated with the particular file offset within the common file is available.

17. The distributed storage network (DSN) of claim 15, wherein the at least one DST EX unit is configured to:

re-associate file offsets associated with subsequent encoded data slices, the subsequent encoded data slices associated with file offsets, within the common file, subsequent to the particular file offset; and

wherein re-associating the file offsets includes associating the subsequent encoded data slices with a decremented file offset.

18. The distributed storage network (DSN) of claim 15, wherein the at least one DST EX unit is configured to:

issue a release-memory request to the file system, wherein the release-memory request includes one or more of;

a file name of the common file, a file offset, or an identified portion of the DS memory that corresponds to a storage location of the encoded data slice.

19. The distributed storage network (DSN) of claim 15, wherein the at least one DST EX unit is configured to:

perform a lookup within a slice mapping table using a slice name to identify at least one of a filename of the common file, or the particular file offset corresponding to the slice name.

20. The distributed storage network (DSN) of claim 15, wherein the at least one DST EX unit is configured to:

interpret the delete-slice request to extract a slice name of the first encoded data slice.