diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 64bac66af25b..6b8332e8c0db 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -341,7 +341,8 @@ static int nilfs_btree_node_broken(const struct nilfs_btree_node *node,
 				   sector_t blocknr)
 {
 	int level, flags, nchildren;
-	int ret = 0;
+	__u64 key, prev_key;
+	int i;
 
 	level = nilfs_btree_node_get_level(node);
 	flags = nilfs_btree_node_get_flags(node);
@@ -356,9 +357,21 @@ static int nilfs_btree_node_broken(const struct nilfs_btree_node *node,
 			   "bad btree node (ino=%llu, blocknr=%llu): level = %d, flags = 0x%x, nchildren = %d",
 			   inode->i_ino, (unsigned long long)blocknr, level,
 			   flags, nchildren);
-		ret = 1;
+		return 1;
 	}
-	return ret;
+
+	for (i = 1, prev_key = nilfs_btree_node_get_key(node, 0);
+	     i < nchildren; i++, prev_key = key) {
+		key = nilfs_btree_node_get_key(node, i);
+		if (unlikely(key <= prev_key)) {
+			nilfs_crit(inode->i_sb,
+				"bad btree node (ino=%llu, blocknr=%llu): unsorted keys at index %d (%llu) and %d (%llu)",
+				inode->i_ino, (unsigned long long)blocknr,
+				i - 1, prev_key, i, key);
+			return 1;
+		}
+	}
+	return 0;
 }
 
 /**