Mechanism for reliable update of virtual disk device mappings without corrupting data

A method of updating mapping data for accessing a storage device within a distributed computing system comprising a plurality of nodes, the method comprising:

• said nodes storing a copy of said mapping data, wherein said mapping data identifies a primary node and an alternate node of the plurality of nodes for accessing said storage device;
• providing an indication to said nodes that an update of said mapping data is pending;
• said nodes suspending data requests to said storage device in response to said indication that an update of said mapping data is pending;
• said nodes waiting for outstanding data requests issued to said storage device to complete;
• said nodes invalidating the stored copy of the mapping data;
• said nodes producing acknowledge signals when the outstanding data requests issued to said storage device are complete;
• updating said mapping data when said acknowledge signals are received from said nodes;
• providing an indication to said nodes that said update is complete;
• said nodes requesting an updated copy of said mapping data in response to said indication that said update is complete;
• and
• said nodes resuming sending said data requests to said storage device.

A method of updating mapping data for accessing a storage device within a distributed computing system comprising a plurality of nodes, the method comprising:

• said nodes storing a copy of said mapping data, wherein said mapping data identifies a primary node and an alternate node of the plurality of nodes for accessing said storage device;
• providing an indication to said nodes that an update of the mapping data is pending;
• said nodes suspending data requests to said storage device in response to said indication to said nodes that an update of the mapping data is pending;
• updating said mapping data;
• providing an indication to said nodes that said update is complete;
• and
• said nodes resuming sending said data requests to said storage device.

A computer-readable storage medium comprising program instructions for updating mapping data for accessing a storage device within a distributed computing system comprising a plurality of nodes, wherein said program instructions execute on the plurality of nodes of the distributed computing system and said program instructions are operable to implement the steps of:

• said nodes storing a copy of said mapping data, wherein said mapping data identifies a primary node and an alternate node of the plurality of nodes for accessing said storage device;
• providing an indication to said nodes that an update of the mapping data is pending;
• said nodes suspending data requests to said storage device in response to indication to said nodes that an update of the mapping data is pending;
• said nodes waiting for outstanding data requests issued to said storage device to complete;
• said nodes invalidating the stored copy of the mapping data;
• said nodes providing acknowledge signals when the outstanding data requests issued to said storage device are complete;
• updating said mapping data when said acknowledge signals are received from said nodes;
• outputting an indication to said nodes that said update is complete;
• said nodes requesting an updated version of said mapping data in response to said indication that said update is complete;
• and
• said nodes resuming sending said data requests to said storage device.