When using MassIndexer and FSDirectory all is okay. When using InfinispanDirectory LockObtainFailedException is thrown.
A test case is attached (MassIndexerTest).
Note that for this test a slightly modified copy of InfinispanDirectoryProvider was needed, as the Infinispan cache instance we use in production is declared in Spring.
Hibernate Core 3.6.5/Hibernate Search 3.4.0/Infinispan 5.0/Spring 3.0.5