Here is the list of some established lock ordering. In this list, A -> B means that you can have A.Lock() then B.Lock(), not the opposite. jetStream -> jsAccount -> Server -> client -> Account jetStream -> jsAccount -> stream -> consumer A lock to protect jetstream account's usage has been introduced: jsAccount.usageMu. This lock is independent and can be invoked under any other lock: jsAccount -> jsa.usageMu, stream -> jsa.usageMu, etc... A lock to protect the account's leafnodes list was also introduced to allow that lock to be held and the acquire a client lock which is not possible with the normal account lock. accountLeafList -> client AccountResolver interface has various implementations, but assume: AccountResolver -> Server