Block-level classification of unstructured data

Methods, apparatus, and processor-readable storage media for block-level classification of unstructured data are provided herein. An example apparatus includes a host device comprising a processor coupled to memory, the host device being configured to communicate over a network with a storage system, and further being configured to: obtain a pointer to a page cache associated with an input-output operation for at least one page of unstructured data of a file; obtain an index node object of the file based at least in part on the pointer to the page cache; derive at least one characteristic of the file based at least in part on the obtained index node object; and provide an indication of the at least one characteristic to the storage system. The storage system determines whether to apply one or more functions to the unstructured data based on the indication.