Merge pull request #27365 from ifed01/wip-ifed-fix-alloc-overflow-luminous

luminous: os/bluestore: fix length overflow.

Reviewed-by: Neha Ojha <nojha@redhat.com>
Reviewed-by: Jianpeng Ma <majianpeng@gmail.com>

diff --cc src/os/bluestore/fastbmap_allocator_impl.h
Simple merge