diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 56f7752ec19a..4c81bc9f48ad 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -350,7 +350,7 @@ static int nilfs_btree_node_broken(const struct nilfs_btree_node *node,
 	if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
 		     level >= NILFS_BTREE_LEVEL_MAX ||
 		     (flags & NILFS_BTREE_NODE_ROOT) ||
-		     nchildren < 0 ||
+		     nchildren <= 0 ||
 		     nchildren > NILFS_BTREE_NODE_NCHILDREN_MAX(size))) {
 		nilfs_crit(inode->i_sb,
 			   "bad btree node (ino=%lu, blocknr=%llu): level = %d, flags = 0x%x, nchildren = %d",