One embodiment of the present invention provides a system that facilitates delayed block allocation in a distributed file system. During operation, the system receives a write command at a client, wherein the write command includes a buffer containing data to be written and a file identifier. In response to receiving the write command, the system reserves a set of disk blocks for the file from a virtual pool of disk blocks allocated to the client. The system also transfers the data to be written to the kernel of the client where the data waits to be transferred to the disk.