# K1621–K1625: block bitmap ownership and metadata reservation

The bounded allocator tracks up to 64 blocks. Every metadata block is marked
reserved and allocated before a bitmap is published. A bitmap that presents
any reserved block as free is rejected. Allocation only selects an unallocated
block, release refuses metadata blocks, and failed operations leave all bits
unchanged. Reserved, user, and free counts partition the device capacity.

The positive test allocates the last free block, 63, then observes no space.
The negative test clears a reserved bit and requires explicit rejection.
These local tests use a synthetic bitmap; real on-disk metadata and six guest
profiles require separate K1625 evidence.