A method, an apparatus, a system, and a computer program product are presented for determining whether a file system, which contains a file system resource that is to be the target of a file system operation, is currently mounted by a data processing system. A first kernel-level process obtains unique identifying information for a file system that contains the target file system resource, and a second kernel-level process manages a data structure having an entry for each file system that the kernel of the data processing system recognizes as being currently mounted. The data structure is searched by the first kernel-level process for an entry having information that matches the unique identifying information such that the first kernel-level process determines that the file system is mounted in response to finding an entry having information that matches the unique identifying information.