In this paper, we propose a novel mobile distributed file system design, which provides high available and reliable storage for files and guarantees that file operations are executed in spite of concurrency and failures. The design is intended to fit mobile clients? devices (e.g., PDAs and cell phones) that have limited storage space and cannot store all data they need, yet they require to access these data at all times. We adopt a server-side caching in order to guarantee sufficient caching space to all mobile clients, and ensure the availability of files in case of clients? failures. We present our algorithm, describe its implementation, and report on its performance evaluation using a cluster of workstations. Our results indicate clearly that our algorithm exhibits a significant degree of automation and conflict-free mobile file system.