A method, computer program product, and data processing system for managing a input/output buffer cache for prevention of deadlocks are disclosed. In a preferred embodiment, automatic buffer cache resizing is performed whenever the number of free buffers in the buffer cache diminishes to below a pre-defined threshold. This resizing adds a pre-defined number of additional buffers to the buffer cache, up to a pre-defined absolute maximum buffer cache size. To prevent deadlocks, an absolute minimum number of free buffers are reserved to ensure that sufficient free buffers for performing a buffer cache resize are always available. In the event that the buffer cache becomes congested and cannot be resized further, threads whose buffer demands cannot be immediately satisfied are blocked until sufficient free buffers become available.