According to one embodiment, a memory system receives from a host a first write request including a first block identifier designating a first write destination block to which first write data is to be written. The memory system acquires the first write data from a write buffer temporarily holding write data corresponding to each of the write requests, and writes the first write data to a write destination page in the first write destination block. The memory system releases a region in the write buffer, storing data which is made readable from the first write destination block by writing the first write data to the write destination page. The data made readable is a data of a page in the first write destination block preceding the write destination page.