ref: a566629485f872d51d4d5661d8b4aa32bd45f3e2
dir: /decisions/
make /adm/frees dynamic? what value does it add? debug extents? there are test cases to debug extents already. that code should be bug free(?) and, even then, /adm/frees would be too slow to debug extents. disk/reconcile is good enough for debugging extents. /adm/ctl can show the free blocks and used blocks anyway.