Systems and methods for read caching in flash storage

A system, comprising:

• a random access memory;
• a flash memory comprising as plurality of physical blocks, each of the plurality of physical blocks comprising a plurality of physical pages;
• a controller, wherein the controller is configured to:
• receive a read request for reading a page of data from the flash memory;
• identify, in a cache tag table stored in the random access memory, a virtual unit address associated with the pane of data;
• in response to identifying the virtual unit address in the cache tan table, determine whether a valid tag line for the page of data is associated with the virtual unit address in the cache tag table, the valid tag line being indexed by a virtual page address for the page of data;
• and
• in response to determining that the valid tag line is associated with the virtual unit address in the cache tag table, read the page of data from the random access memory in accordance with the read request.

A flash controller, comprising non-transitory instructions stored therein that, when executed by the controller, perform the operations of:

• receiving a read request for reading a page of data from a one or more flash memory devices;
• identifying, in a cache tag table stored in a cache memory different from the flash memory, a virtual unit address associated with the page of data;
• in response to identifying the virtual unit address in the cache tag table, determining whether a valid tag line for the page of data is associated with the virtual unit address in the cache tag table, the valid tag line being indexed by a virtual page address for the page of data;
• and
• in response to determining that the valid tag line is associated with the virtual unit address in the cache tag table, reading the page of data from the cache memory in accordance with the read request.