Persistent caching directory level support

• US 20050165735A1
• Filed: 02/22/2005
• Published: 07/28/2005
• Est. Priority Date: 10/23/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Lin, Yun, Virk, Navjot, Aust, Brian S., Steere, David C., Pardikar, Shishir P., Samji, Mohammed A.
• Granted Patent: US 7,698,376 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching

Abstract

The present invention provides a novel client side caching (CSC) infrastructure that supports transition states at the directory level to facilitate a seamless operation across connectivity states between client and remote server. More specifically, persistent caching is performed to safeguard the user (e.g., client) and/or the client applications across connectivity interruptions and/or bandwidth changes. This is accomplished in part by caching to a client data store the desirable file(s) together with the appropriate file access parameters. Moreover, the client maintains access to cached files during periods of disconnect. Furthermore, portions of a path can be offline while other portions upstream can remain online. CSC operates on the logical path which cooperates with DFS which operates on the physical path to keep track of files cached, accessed and changes in the directories. In addition, truth on the client is facilitated whether or not a conflict of file copies exists.

Claims

1. A method that facilitates seamless operation across connectivity states between at least one client and at least one remote server, comprising:

providing at least a first surrogate provider that receives one or more I/O requests from an MUP, the first surrogate provider comprising a pre-process handler and a post-process handler that facilitate handling the requests at a directory level, the first surrogate provider examining a logical path of the request;

passing the one or more requests to a second surrogate provider that is operational in an online state, the second surrogate provider translating the logical path of the request into a physical path; and

generating one or more data structures for each respective I/O request that facilitates determining whether the first surrogate provider wants to own or cache a file object related to the request.

2. The method of claim 1, further comprising:

processing the request using the pre-process handler to determine whether the request was handled by at least one of a network provider and the first surrogate provider;

optionally calling the post-process handler after the request is handled to handle the request again;

optionally passing the request to a second surrogate provider, the second surrogate provider examines the request and maps the request path to a physical path at the directory level; and

optionally passing the request to one or more redirectors to allow the one or more redirectors to claim ownership of a file object requested.

3. The method of claim 1, the request is a create request.

4. The method of claim 1, the first surrogate provider is a CSC component and the second surrogate provider is a DFS component, the DFS identifying DFS links in cooperation with the CSC component only while online.

5. The method of claim 1, the request being one of a read and a write operation request.

6. The method of claim 5, the first surrogate provider is provided with a buffering state of a file before substantially every read from a persistent cache to a client application or before substantially every write is executed, respectively.

7. The method of claim 1, employing the first surrogate provider to keep track of DFS links corresponding to every object, wherein the DFS links are physical shares.

8. The method of claim 1, employing the first surrogate provider to determine whether the request against a specific object should be carried out offline or not, before returning to MUP, by looking at a corresponding physical share connection state.

9. A system that facilitates seamless operation across connectivity states between at least one client and at least one remote server, comprising:

means for providing at least a first surrogate provider that receives one or more I/O requests from an MUP, the first surrogate provider comprising a pre-process handler and a post-process handler that facilitate handling the requests at a directory level, the first surrogate provider examining a logical path of the request;

means for passing the one or more requests to a second surrogate provider that is operational in an online state, the second surrogate provider translating the logical path of the request into a physical path; and

means for generating one or more data structures for each respective I/O request that facilitates determining whether the first surrogate provider wants to own or cache a file object related to the request.