static inline void __d_add(struct dentry *dentry, struct inode *inode)
{
	struct inode *dir = NULL;
	unsigned n;
	spin_lock(&dentry->d_lock);
	if (unlikely(d_in_lookup(dentry))) {
		dir = dentry->d_parent->d_inode;
		n = start_dir_add(dir);
		__d_lookup_done(dentry);
	}
	if (inode) {
		unsigned add_flags = d_flags_for_inode(inode);
		hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
		raw_write_seqcount_begin(&dentry->d_seq);
		__d_set_inode_and_type(dentry, inode, add_flags);
		raw_write_seqcount_end(&dentry->d_seq);
		fsnotify_update_flags(dentry);
	}
	__d_rehash(dentry);
	if (dir)
		end_dir_add(dir, n);
	spin_unlock(&dentry->d_lock);
	if (inode)
		spin_unlock(&inode->i_lock);
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.