Module block 

Typed diff-area records: the block descriptor and store block range.

Phase 1 parses these two records so a consumer sees the copy-on-write mapping structurally. The full snapshot-reconstruction engine (overlaying diff-area blocks to materialize a snapshot’s view of the volume) is Phase 2 and is deliberately not implemented here.

Structs

BlockDescriptor

A 32-byte diff-area block descriptor: it maps an original volume block to the copy-on-write block saved in the store.

BlockDescriptorFlags

Flags on a block descriptor.

StoreBlockRange

A 24-byte store block range record.

Constants

BLOCK_DESCRIPTOR_LEN

Length of a block descriptor record, in bytes.

STORE_BLOCK_RANGE_LEN

Length of a store block range record, in bytes.