System and method for managing hard and soft lock state information in a distributed storage system environment

A method of managing lock state information in a system including a plurality of data volumes of a striped volume set, comprising:

• configuring a meta-data volume node that includes a lock state database that stores lock state information for one or more data containers on the striped volume set;
• communicating the lock state information including an input/output operation result for input/output requests from said meta-data volume node to one or more data volume nodes of the system, using lock state command messages;
• in response to said meta-data volume node receiving a request from a client for exclusive access to a range of a data container, searching said lock state database for conflicting locks, and if no such locks are found, granting a lock with respect to said range;
• constructing a lock state database structure in said lock state database, said lock state data structure adapted to send messages to a data volume node, the messages including information about the client requesting the exclusive access, a lock state access type, a lock access range and an input/output operation result;
• in response to said meta-data volume receiving a client request to add a new lock to a file in a striped volume environment, consulting at said meta-data volume node, a striping table to determine striping rules for said file;
• using striping rules from said striping table, and a file range of the new lock being added, and determining at said meta-data volume, which data volume nodes are impacted by the addition of the new lock;
• and
• for each such data volume node listed in a list of impacted data volume nodes, performing at said meta-data volume the following:
• if the new lock overlaps with a byte range with no locks present, or locks which are marked as having been cached by the data volume node in question, then the meta-data volume node sends a message to that data volume node, informing it of the new lock and that the file range covered by the new lock is invalid.

A system configured to manage lock state information in a system, the system comprising:

• two or more nodes connected together to form a cluster, each node in the cluster being associated with at least one data volume of a plurality of data volumes and each data volume is a logical arrangement of a plurality of storage devices connected to the node;
• one or more data containers striped across the plurality of volumes in a striped volume set;
• a plurality of data volume nodes adapted to receive data access requests from a client directed to a data container or range of the data container;
• and
• a meta-data volume node configured to communicate with said data volume nodes and configured to include a lock state database that stores lock state information for the data container, and to provide input/output operation results to data access requests received from a client at said data volume node;
• a striping table to determine striping rules for files, said meta-data volume being configured to consult said striping table to determine striping rules for said file;
• said meta-data volume being further configured to use striping rules from said striping table, and a file range of a new lock being added, to determine at said meta-data volume, which data volume nodes are impacted by the addition of the new lock;
• said meta-data volume being further configured to receive a message from a data volume regarding client requests for I/O operations, and the meta-data volume checks the lock state database for conflicting locks, and in response to said meta-data volume node finding that there are conflicting locks, then the meta-data volume nodes sends an acknowledgement to the data volume notifying the data volume of the existing conflicting lock and further indicating that the request should be denied;
• said meta-data volume node being further configured such that, if there are supporting locks then the meta-date volume sends an access request with supporting lock information and indicating that the request should be allowed;
• said meta-data volume node further configured to send an access request acknowledgment message indicating that I/O operation is permitted and a Boolean indication that the data volume issuing the request has all the locks associated with that range after which the data volume node completes the client request.

A computer readable storage medium containing executable program instructions executed by a processor, comprising:

• program instructions that connect two or more nodes together to form a cluster, each node in the cluster being associated with at least one data volume of a plurality of data volumes and each data volume is a logical arrangement of a plurality of storage devices connected to the node storing each data volume;
• program instructions that stripe one or more data containers across the plurality of volumes in the striped volume set in accordance with a striping table containing striping rules;
• program instructions that configure a meta-data volume node that includes a lock state database that stores comprehensive lock state information for one or more data containers stored on the system;
• program instructions that communicate lock state information and input/output operation results between said meta-data volume node and one or more data volume nodes of said system, using lock state command messages, said instructions including the meta-data volume node receiving a message from a data volume node regarding client requests for I/O operations,
• program instructions that further configure said meta-data volume that in response to receiving a client request for a file in a striped environment, to consult a-at said meta-data volume node, a striping table to determine striping rules for files;
• using said striping rules from said striping table, and a file range of a new lock being added, and determining at said meta-data volume, which data volume nodes are impacted by the addition of the new lock;
• program instructions that further provide that the meta-data volume checks the lock state database for conflicting locks, and in response to said meta-data volume node finding that there are conflicting locks, then the meta-data volume node sends an acknowledgement to the impacted data volume node notifying it of the existing conflicting locks, and further indicating that the request should be denied;
• program instructions that said meta-data volume node further checks the lock state database for supporting locks and if there are supporting locks then the meta-data volume node sends an access request to the impacted data volume node with supporting lock information and indicates that the request should be allowed;
• and
• said meta-data volume node further sends an access request acknowledgment message indicating that I/O operation is permitted and a Boolean indication that the impacted data volume issuing the request has the locks associated with that range after which the data volume node completes the client request.