SYSTEM AND METHOD FOR HIJACKING INODES BASED ON REPLICATION OPERATIONS RECEIVED IN AN ARBITRARY ORDER

• US 20160139843A1
• Filed: 01/22/2016
• Published: 05/19/2016
• Est. Priority Date: 09/14/2009
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Shah, Devang K., Driscoll, Alan S.
• Granted Patent: US 9,858,001 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/178 Techniques for file synchronisation in file systems
• CPC Class Codes: G06F 16/2365 Ensuring data consistency and integrity
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A system and method for hijacking inodes based on replication operations received in an arbitrary order is used to assist a data replication operation from a source storage system to a destination storage system. The source storage system generates a set of replication operations as part of a replication process and transmits the replication operations in an arbitrary order. After receiving a replication operation, the system determines whether the operation is inconsistent with a corresponding destination inode. If an inconsistency exists, the system hijacks the destination inode by replacing the destination inode'"'"'s metadata with data determined based on the replication operation. The system may also delete metadata from the inode and/or initialize metadata to default values if the metadata was not replaced based on the replication operation. The system then waits for a second replication operation that contains the remaining metadata and replaces the metadata based on the second replication operation. In addition, data blocks associated with the previous version of the inode are freed.

Claims

1-22. -22. (canceled)

23. An apparatus, comprising:

a storage operation interface configured to receive multiple replication operations for execution on a destination storage system, wherein the multiple replication operations include a first replication operation defining a modify operation directed to a metadata container type that differs from a destination metadata container type and a second replication operation defining a create operation; and

logic, at least a portion of which is implemented in hardware, the logic to process storage operations in a network storage system, the logic comprising a highjack component to store metadata in a first part of a destination metadata container based on the first replication operation and to store metadata in a second part of the destination metadata container based on the second replication operation.

24. The apparatus of claim 23, wherein the multiple replication operations are received in an arbitrary order.

25. The apparatus of claim 23, wherein each replication operation includes a target metadata container identifier.

26. The apparatus of claim 23, comprising a storage interface to communicate with the destination storage system.

27. The apparatus of claim 23, comprising a lookup component to find a matching metadata container on the destination storage system corresponding to an individual target metadata container address.

28. The apparatus of claim 27, comprising an evaluation component to detect an inconsistency between an individual replication operation corresponding to the individual target metadata container address and the matching metadata container and to determine, based on the detection, that the individual replication operation is a replacement operation.

29. The apparatus of claim 28, wherein the evaluation component is configured to:

determine that the replication operation is directed to create the matching metadata container that already exists in the destination storage system;

or

determine that one of the replication operations is directed to modify the matching metadata container that is unused;

or

determine that a target type of one of the replication operations differs from a metadata container type of the matching metadata container;

or

determine that a target generation of one of the replication operations differs from a metadata container generation of the matching metadata container, or

determine that one of the replication operation is inconsistent with the type of the matching metadata container.

30. A computer-implemented method, comprising:

receiving multiple replication operations for execution on a destination storage system in an arbitrary order, wherein the multiple replication operations include a first replication operation defining a modify operation directed to a metadata container type that differs from a destination metadata container type and a second replication operation defining a create operation;

storing metadata in a first part of a destination metadata container based on the first replication operation; and

storing metadata in a second part of the destination metadata container based on the second replication operation.

31. The method of claim 30, wherein each replication operation includes a target metadata container identifier.

32. The method of claim 30, comprising:

detecting an inconsistency between an individual replication operation and the destination metadata container on the destination storage system when the destination storage system cannot properly execute the individual replication operation;

determining, in response to detecting the inconsistency, that a replacement operation has occurred; and

replacing a portion of a metadata section of the destination metadata container based on the individual replication operation.

33. The method of claim 32, wherein detecting the inconsistency comprises:

determining that the replication operation is directed to create the destination metadata container that already exists in the destination storage system;

or

determining that the replication operation is directed to modify the destination metadata container that is unused;

or

determining that a target type of the replication operation differs from a metadata container type of the destination metadata container;

or

determining that the replication operation is inconsistent with the type of the destination metadata container.

34. The method of claim 33, wherein the replication operation inconsistent with the type of the destination metadata container is a replication operation to add data blocks to the destination metadata container of a directory, or a replication operation to add a directory entry to the destination metadata container of a file.

35. The method of claim 32, wherein the destination metadata container is a file and wherein replacing the portion of the metadata section comprises freeing a first set of metadata blocks associated with the file and associating a second set of metadata blocks determined based on the replication operation.

36. The method of claim 30, wherein the arbitrary order is not based on chronological order or file system hierarchy.

37. One or more computer-readable media to store instructions that when executed by a processor circuit causes the processor circuit to:

receive multiple replication operations for execution on a destination storage system in an arbitrary order, wherein the multiple replication operations include a first replication operation defining a modify operation directed to a metadata container type that differs from a destination metadata container type and a second replication operation defining a create operation;

store metadata in a first part of a destination metadata container based on the first replication operation; and

store metadata in a second part of the destination metadata container based on the second replication operation.

38. The one or more computer-readable media of claim 37, each replication operation to include a target metadata container identifier.

39. The one or more computer-readable media of claim 37, with instructions to:

detect an inconsistency between an individual replication operation and the destination metadata container on the destination storage system when the destination storage system cannot properly execute the individual replication operation;

determine, in response to detecting the inconsistency, that a replacement operation has occurred; and

replace a portion of a metadata section of the destination metadata container based on the individual replication operation.

40. The one or more computer-readable media of claim 39, with instructions to:

determine that the replication operation is directed to create the destination metadata container that already exists in the destination storage system to detect the inconsistency;

or

determine that the replication operation is directed to modify the destination metadata container that is unused to detect the inconsistency;

or

determine that a target type of the replication operation differs from a metadata container type of the destination metadata container to detect the inconsistency;

or

determine that the replication operation is inconsistent with the type of the destination metadata container to detect the inconsistency.

41. The one or more computer-readable media of claim 39, wherein the replication operation inconsistent with the type of the destination metadata container is a replication operation to add data blocks to the destination metadata container of a directory, or a replication operation to add a directory entry to the destination metadata container of a file.

42. The one or more computer-readable media of claim 39, wherein the destination metadata container is a file and wherein replacing the portion of the metadata section comprises freeing a first set of metadata blocks associated with the file and associating a second set of metadata blocks determined based on the replication operation.