Efficient file management through granular opportunistic locking
First Claim
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1. A method for maintaining distributed cache coherency across multiple clients accessing a file or a shared resource, comprising:
- opening a file handle with an oplock key associated to a first client;
receiving a request from the first client for a first oplock state, the request indicating an intent to locally cache one or more of;
write data, read data, and the file handle;
granting the first oplock state to the first client; and
in response to receiving an acknowledgement that the first oplock state is broken, transitioning from the first oplock state by granting the first client a second oplock state that is different from the first oplock state.
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Accused Products
Abstract
Improved methods and systems for granular opportunistic locking mechanisms (oplocks) are provided for increasing file caching efficiency. Oplocks can be specified with a combination of three possible granular caching intentions: read, write, and/or handle. An oplock can be specified with an identifier that indicates a client/specific caller to avoid breaking the original oplock due to an incompatibility from other requests of the same client. An atomic oplock flag is added to create operations that allow callers to request an atomic open with an oplock with a given file.
7 Citations
18 Claims
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1. A method for maintaining distributed cache coherency across multiple clients accessing a file or a shared resource, comprising:
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opening a file handle with an oplock key associated to a first client; receiving a request from the first client for a first oplock state, the request indicating an intent to locally cache one or more of;
write data, read data, and the file handle;granting the first oplock state to the first client; and in response to receiving an acknowledgement that the first oplock state is broken, transitioning from the first oplock state by granting the first client a second oplock state that is different from the first oplock state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A file server comprising:
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a storage having a file directed for shared usage; an interface to a network; and a processor, the storage operating from control signals of the processor to enforce opportunistic locking semantics for accessing the storage across the network, the opportunistic locking semantics enforced among the plurality of clients, the processor configured to; open a file handle of the file directed for shared usage with an oplock key associating a first client to the file handle; receive a request from the first client for a first oplock state, the request indicating an intent to locally cache one or more of;
write data, read data, and the file handle;grant a first oplock state to the first client; and transition from the first oplock state to a second oplock state different from the first oplock state in response to receiving an acknowledgement that the first oplock state is broken. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for allocating and managing files in a multi-user network environment having at least one server with a file directed for shared usage, comprising:
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opening a file handle with an oplock key associated to a first client, wherein the oplock key prevents two or more file handles from the first client from breaking each other'"'"'s oplock state; granting a first oplock state as specified by a first client request, the first client request indicating an intent to perform locally one or more of;
read caching, write caching, or handle caching; andtransitioning from the first oplock state as specified to a second oplock state upon receiving an acknowledgement that the first oplock state is broken, the transitioning comprising; notifying the first client that the first oplock state is broken in response to receiving a second client request without the oplock key; providing an opportunity for the client to flush any unwritten data to the server, re-open any handles which were collapsed on the client, close any cached handles and purge its read cache; transmitting the oplock key to a file system control to store the oplock key; performing a share check to determine a sharing violation, and upon discovering a sharing violation breaking existing handle oplocks, if any; performing the share check for a second time; and upon discovery of a sharing violation, failing any file open requests. - View Dependent Claims (18)
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Specification