xfs: fix integer overflow in busy extent sort comparator

xfs_extent_busy_ag_cmp() subtracts two uint32_t values (group
numbers and block numbers) and returns the result as s32. When
the difference exceeds INT_MAX, the result overflows and the sort
order is corrupted.

Use cmp_int() instead, as was done in commit 362c490 ("xfs:
fix integer overflow in bmap intent sort comparator").

Fixes: 4a137e0 ("xfs: keep a reference to the pag for busy extents")
Signed-off-by: Yuto Ohnuki <ytohnuki@amazon.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

Author: Yuto Ohnuki

fs/xfs/xfs_extent_busy.c

@@ -690,9 +690,9 @@ xfs_extent_busy_ag_cmp(
 		container_of(l2, struct xfs_extent_busy, list);
 	s32 diff;
 
-	diff = b1->group->xg_gno - b2->group->xg_gno;
+	diff = cmp_int(b1->group->xg_gno, b2->group->xg_gno);
 	if (!diff)
-		diff = b1->bno - b2->bno;
+		diff = cmp_int(b1->bno, b2->bno);
 	return diff;
 }