hlist_bl_first
dentry = dget(hlist_bl_entry(hlist_bl_first(&sb->s_roots), struct dentry, d_hash));
node = hlist_bl_first(head);
for (pos = hlist_bl_first(head); \
for (pos = hlist_bl_first(head); \
struct hlist_bl_node *first = hlist_bl_first(h);
first = hlist_bl_first(h);