Many threads blocked in com.arjuna.ats.internal.arjuna.objectstore.FileSystemStore.createHierarchy

Issue

I found a lot of blocked threads, in a thread dump and most threads are blocked in the same place:

java.lang.Thread.State: BLOCKED (on object monitor)
at com.arjuna.ats.internal.arjuna.objectstore.FileSystemStore.createHierarchy(FileSystemStore.java:630)
- waiting to lock <0x00000000b4e70b28> (a com.arjuna.ats.internal.arjuna.objectstore.ShadowNoFileLockStore)
at com.arjuna.ats.internal.arjuna.objectstore.FileSystemStore.openAndLock(FileSystemStore.java:376)
at com.arjuna.ats.internal.arjuna.objectstore.ShadowingStore.write_state(ShadowingStore.java:545)
at com.arjuna.ats.internal.arjuna.objectstore.FileSystemStore.write_committed(FileSystemStore.java:134)
at com.arjuna.ats.arjuna.coordinator.BasicAction.prepare(BasicAction.java:2216)
- locked <0x00000000cdd4b728> (a com.arjuna.ats.internal.jta.transaction.arjunacore.AtomicAction)
at com.arjuna.ats.arjuna.coordinator.BasicAction.End(BasicAction.java:1474)
- locked <0x00000000cdd4b728> (a com.arjuna.ats.internal.jta.transaction.arjunacore.AtomicAction)
at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.end(TwoPhaseCoordinator.java:98)
at com.arjuna.ats.arjuna.AtomicAction.commit(AtomicAction.java:164)
at com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionImple.commitAndDisassociate(TransactionImple.java:1165)
at com.arjuna.ats.internal.jta.transaction.arjunacore.BaseTransaction.commit(BaseTransaction.java:117)
at com.arjuna.ats.jbossatx.BaseTransactionManagerDelegate.commit(BaseTransactionManagerDelegate.java:75)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.endTransaction(CMTTxInterceptor.java:91)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:231)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:303)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:189)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ejb3.remote.EJBRemoteTransactionPropagatingInterceptor.processInvocation(EJBRemoteTransactionPropagatingInterceptor.java:80)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ejb3.component.interceptors.ShutDownInterceptorFactory$1.processInvocation(ShutDownInterceptorFactory.java:42)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:59)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ejb3.component.interceptors.AdditionalSetupInterceptor.processInvocation(AdditionalSetupInterceptor.java:32)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.as.ee.component.TCCLInterceptor.processInvocation(TCCLInterceptor.java:45)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
at org.jboss.as.ee.component.ViewService$View.invoke(ViewService.java:165)
at org.jboss.as.ejb3.remote.LocalEjbReceiver.processInvocation(LocalEjbReceiver.java:222)
at org.jboss.ejb.client.EJBClientInvocationContext.sendRequest(EJBClientInvocationContext.java:179)
at org.jboss.ejb.client.TransactionInterceptor.handleInvocation(TransactionInterceptor.java:43)
at org.jboss.ejb.client.EJBClientInvocationContext.sendRequest(EJBClientInvocationContext.java:181)
at org.jboss.ejb.client.ReceiverInterceptor.handleInvocation(ReceiverInterceptor.java:125)
at org.jboss.ejb.client.EJBClientInvocationContext.sendRequest(EJBClientInvocationContext.java:181)
at org.jboss.ejb.client.EJBInvocationHandler.doInvoke(EJBInvocationHandler.java:136)
at org.jboss.ejb.client.EJBInvocationHandler.doInvoke(EJBInvocationHandler.java:121)
at org.jboss.ejb.client.EJBInvocationHandler.invoke(EJBInvocationHandler.java:104)
...