Provided are a method, system, and program for performing an Input/Output (I/O) operation with respect to a logical device capable of being accessed by multiple host systems. Metadata in the logical device that is required in order to access the data in the logical device is overwritten to prevent at least one host system from accessing the data in the logical device represented by the overwritten metadata. An I/O operation is performed with respect to the logical device. Valid metadata is written to the logical device to enable host systems to access the data in the logical device represented by the metadata.