diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
index a9a1422..dda08f3 100644
--- a/fs/btrfs/print-tree.c
+++ b/fs/btrfs/print-tree.c
@@ -45,7 +45,7 @@
 	}
 	printf("node %Lu level %d total ptrs %d free spc %u\n", t->blocknr,
 	        node_level(c->header.flags), c->header.nritems,
-		NODEPTRS_PER_BLOCK - c->header.nritems);
+		(u32)NODEPTRS_PER_BLOCK - c->header.nritems);
 	fflush(stdout);
 	for (i = 0; i < nr; i++) {
 		printf("\tkey %d (%Lu %u %Lu) block %Lu\n",