Various embodiments of the present invention provide a method and apparatus for reusing a storage block of a file system. The file system is based on a thin provision storage configuration and shares a storage pool with a further file system. The method comprises detecting an unused storage block in a storage space of the file system in response to a predefined trigger event. The method further comprises in response to an unused storage block being detected in the storage space, providing the unused storage block to the storage pool for being reused. According to various embodiments of the present invention, effective utilization of the storage space of the storage pool is achieved.