xfs: fix broken MAXREFCOUNT handling This series fixes a bug in the refcount code where we don't merge records correctly if the refcount is hovering around MAXREFCOUNT. This fixes regressions in xfs/179 when fsdax is enabled. xfs/179 itself will be modified to exploit the bug through the pagecache path. Signed-off-by: Darrick J. Wong <djwong@kernel.org>