In “Concurrent Programming with Chain Locking,” Gigi Sayfan presents a C# class demonstrating chain locked operations on a hierarchical data structure. This reminded me of lock hierarchies described by Anthony Williams in the book C++ Concurrency in Action.
To take a step back for a moment, the overall goal is to create multithreaded code which doesn’t cause deadlocks, race conditions, etc. Although it may seem like a confusion of metaphors, lock hierarchies are a type of hand-over-hand locking, which is basically defined lock ordering. I think it would be fair to call a “chain” a particular path of locking through a hierarchy. Defining lock ordering is what you do if you can’t do the better idea, which is to acquire two of more locks in a single operation, for instance with the C++11
As Herb Sutter pointed out in his article “Use Lock Hierarchies to Avoid Deadlock,” you may already have layers in your application (or at least the data in a certain context). This can be taken advantage of when making the software concurrency-friendly. The general idea is that a layer does not access code in layers above it. For mutexes, this means that a layer cannot lock a mutex if it already holds a mutex from a lower layer.