Merge tag 'repair-use-in-memory-btrees-6.9_2024-06-03' of https://git.kernel.org...

xfs_repair: use in-memory rmap btrees [v30.5 08/35]

Now that we've ported support for in-memory btrees to userspace, port
xfs_repair to use them instead of the clunky slab interface that we
currently use.  This has the effect of moving memory consumption for
tracking reverse mappings into a memfd file, which means that we could
(theoretically) reduce the memory requirements by pointing it at an
on-disk file or something.  It also enables us to remove the sorting
step and to avoid having to coalesce adjacent contiguous bmap records
into a single rmap record.

This has been running on the djcloud for months with no problems.  Enjoy!

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>