Receiving at a cache node notification of changes to files in a source file system served from a cache file system at the cache node

Patent metadata

Field	Value
Publication number	US-11650957-B2
Application number	US-202117336069-A
Country	US
Kind code	B2
Filing date	Jun 1, 2021
Priority date	Jun 1, 2021
Publication date	May 16, 2023
Grant date	May 16, 2023

Abstract

Provided are a computer program product, system, and method receiving at a cache node notification of changes to files in a source file system served from a cache file system at the cache node. A cache file system is established at the cache node as a local share of a source file system at the source node. The source node establishes a local share of the cache file system at the cache node. Notification is received, from the source node, that the source node modified a source control file for a source file at the source node. In response to receiving the notification, a cache control file, for a cached file in the cache file system, is updated to indicate the source file at the source node is modified. A request is sent to the source node to obtain data for the source file indicated as modified.

First claim

What is claimed is:

1. A computer program product for caching data from a source node at a cache node over a network, wherein the computer program product comprises a computer readable storage medium having computer readable program instructions to cause the cache node to perform operations, the operations comprising:
establishing, at the cache node, a cache file system as a local share of a source file system at the source node, wherein the source node establishes a local share of the cache file system at the cache node;
receiving notification, from the source node, that the source node modified a source control file in the local share of the cache file system for a source file at the source node;
in response to receiving the notification, updating a cache control file, for a cached file in the cache file system comprising a copy of the source file, to indicate the source file at the source node is modified;
in response to a request for data in the source file from an application, determining whether the cache control file indicates the requested data in the cache is modified at the source node; and
sending a request to the source node to obtain data for the source file in response to determining that the cache control file indicates the requested data as modified.

2. The computer program product of claim 1 , wherein the operations further comprise:
returning data for the cached file from the cache file system to the application request in response to the cache control file indicating that the source file is not modified.

3. The computer program product of claim 1 , wherein the operations further comprise:
sending a control file request to the source node to reverse mount the cache file system at the source node to establish the local share of the cache file system.

4. The computer program product of claim 3 , wherein the operations further comprise:
mounting the cache file system at the cache node in response to an export request from the source node to establish the local share of the source file system at the cache node; and
sending the control file request to the source node in response to mounting the cache file system at the cache node to cause the source node to reverse mount the local share of the cache file system at the cache node comprising.

5. A computer program product for caching data from a source node at a cache node over a network, wherein the computer program product comprises a computer readable storage medium having computer readable program instructions to cause the cache node to perform operations, the operations comprising:
establishing, at the cache node, a cache file system as a local share of a source file system at the source node, wherein the source node establishes a local share of the cache file system at the cache node;
receiving notification, from the source node, that the source node modified a source control file for a source file at the source node;
in response to receiving the notification, updating a cache control file, for a cached file in the cache file system comprising a copy of the source file, to indicate the source file at the source node is modified, wherein the source control file and the cache control file include a state bit that indicates whether metadata for the source file was modified at the source node and a cache bit indicating whether data for the source file was modified at the source node, wherein the notification indicates whether the cached bit and the state bit were reset to indicate changes to the cached bit and state bit in the source control file, respectively; and
sending a request to the source node to obtain data for the source file indicated as modified in the cache control file in response to an application request for the source file.

6. The computer program product of claim 5 , wherein the operations further comprise:
returning to the application request metadata and/or data of the cached file in the cache file system in response to the cache control file indicating no change to the state bit and no change to the cache bit.

7. The computer program product of claim 5 , wherein the operations further comprise:
in response to the application request for the metadata for the source file, requesting metadata for the source file from the source node in response to the cache control file indicating a change to the state bit and no change to the cache bit; and
setting the state bit to indicate no change in response to receiving the requested metadata for the source file and storing in the cache file system.

8. The computer program product of claim 5 , wherein the operations further comprise:
in response to the application request to read data from the source file, submitting a read request to the source node to read the data for the source file in response to the cache control file indicating a change to the cache bit.

9. A system for caching data from a source node at a cache node over a network, comprising:
a processor; and
a computer readable storage medium having computer readable program instructions executed by the processor to cause the cache node to perform operations, the operations comprising:
establishing, at the cache node, a cache file system as a local share of a source file system at the source node, wherein the source node establishes a local share of the cache file system at the cache node;
receiving notification, from the source node, that the source node modified a source control file in the local share of the cache file system for a source file at the source node;
in response to receiving the notification, updating a cache control file, for a cached file in the cache file system comprising a copy of the source file, to indicate the source file at the source node is modified;
in response to a request for data in the source file from an application, determining whether the cache control file indicates the requested data in the cache is modified at the source node; and
sending a request to the source node to obtain data for the source file in response to determining that the cache control file indicates the requested data as modified.

10. The system of claim 9 , wherein the operations further comprise:
sending a control file request to the source node to reverse mount the cache file system at the source node to establish the local share of the cache file system.

11. The system of claim 10 , wherein the operations further comprise:
mounting the cache file system at the cache node in response to an export request from the source node to establish the local share of the source file system at the cache node; and
sending the control file request to the source node in response to mounting the cache file system at the cache node to cause the source node to reverse mount the local share of the cache file system at the cache node comprising.

12. A system for caching data from a source node at a cache node over a network, comprising:
a processor; and
a computer readable storage medium having computer readable program instructions executed by the processor to cause the cache node to perform operations, the operations comprising:
establishing, at the cache node, a cache file system as a local share of a source file system at the source node, wherein the source node establishes a local share of the cache file system at the cache node;
receiving notification, from the source node, that the source node modified a source control file for a source file at the source node;
in response to receiving the notification, updating a cache control file, for a cached file in the cache file system comprising a copy of the source file, to indicate the source file at the source node is mod

Assignees

• IBM

Inventors

• Puvvada Venkateswara Rao
• K G Karrthik
• Kumar Saket
• Komanduri Ravi Kumar

Classifications

• G06F16/172 Primary

  Caching, prefetching or hoarding of files · CPC title