* Threading issue: Multiple threads at system startup could in
		 * principle call this function simultaneously. They will
		 * therefore each set the cwdPathPtr independently, which is a
		 * bit peculiar, but should be fine. Once we have a cwd, we'll
		 * always be in the 'else' branch below which is simpler.
		 */

		ClientData cd = (ClientData) Tcl_FSGetNativePath(norm);

		FsUpdateCwd(norm, TclNativeDupInternalRep(cd));
		Tcl_DecrRefCount(norm);
	    }
	    Tcl_DecrRefCount(retVal);
	} else {
	    /*

	 * Avoid possible segfaults or nondeterministic memory leaks where the
	 * reference count has been incorreclty managed.
	 */
	Tcl_Panic("Tcl_FSGetFileSystemForPath called with object with refCount == 0");
	return NULL;
    }

    /* Start with an up-to-date copy of the master filesystem. */
    fsRecPtr = FsGetFirstFilesystem();
    Claim();

    /*
     * Ensure that pathPtr is a valid pathname.
     */
    if (TclFSEnsureEpochOk(pathPtr, &retVal) != TCL_OK) {