void d_exchange(struct dentry *dentry1, struct dentry *dentry2)
{
	write_seqlock(&rename_lock);

	WARN_ON(!dentry1->d_inode);
	WARN_ON(!dentry2->d_inode);
	WARN_ON(IS_ROOT(dentry1));
	WARN_ON(IS_ROOT(dentry2));

	__d_move(dentry1, dentry2, true);

	write_sequnlock(&rename_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.