public synchronized void clear() {
		for (Entry<FSRLRoot, FSCacheInfo> entry : filesystems.entrySet()) {
			try {
				FSCacheInfo fci = entry.getValue();
				FileSystemRef ref = fci.ref;
				GFileSystem fs = ref.getFilesystem();
				if (!ref.getFilesystem().getRefManager().canClose(ref)) {
					Msg.warn(this, "Forcing filesystem closed: " + fs);
				}
				fs.close();
			}
			catch (IOException e) {
				Msg.warn(this, "Error closing filesystem: " + e);
			}
		}
		filesystems.clear();
	}
Forcefully closes any filesystems in the cache, then clears the list of
cached filesystems.
Ghidra/Features/Base/src/main/java/ghidra/formats/gfilesystem/FileSystemInstanceManager.java