Systems and methods for I/O fencing in a shared storage environment are
provided. Prior to initiating an I/O request, when feasible, the current
time from a local timer is compared to the current state of an interval
obtained for the target device. As a result, a device reset occurring
while the interval is viable does not arbitrarily end a multiphase I/O
operation. However, a device reset occurring once the lease has expired
results in a delay or termination of the multiphase I/O operation. As a
result, multiphase I/O operations from initiating hosts that have lost
contact with the shared storage environment are not allowed to corrupt
the shared storage devices.