Storage systems track free blocks using various data structures and maps. For instance, free block maps may contain data blocks with values that indicate whether a block is free or not. When an operation results in a block being freed, the relevant data block in the maps must be written during an I/O operation to update the value. Large numbers of updates my occur after an operation that frees a large numbers of blocks, which can lead to performance degradation. Accordingly, disclosed are systems and methods for deferring updating of free block data tracking structures using logs.