A method, computer program product and/or system saves an original logical block in a file system and generates a first heatmap reflecting access operations on the original logical block. After taking of a file system snapshot, and receiving information that the original logical block is going to be revised, a second heatmap is generated, reflecting predicted access operations on the revised logical block. The second heatmap is based, at least in part, on the first heatmap. Selecting a physical storage location for the revised logical block is based on the second heatmap.