1. A method of processing a write operation comprising: receiving the write operation on a data storage system, the write operation indicating to write first data to a target location of a logical address range of a logical device; determining whether the target location is mapped to physical storage; responsive to determining that the target location is not mapped to physical storage, performing first processing to service the write operation, the first processing comprising: sending the write operation along with a hint to a caching layer, the hint indicating to store zeroes to locations that do not include user data; forming, by the caching layer, a data portion denoting data stored at a logical address subrange of the logical address range of the logical device, said logical address subrange including the target location, said data portion including the first data stored at the target location and zeroes that are stored at remaining locations of the logical address subrange and that denote locations of the logical address subrange not including user data; and storing, by the caching layer, the data portion in cache.