usb hubs, hotplug support, unplug support, saving log files to disk, smt

code/drivers/storage/ahci/ahci.h

@@ -344,6 +344,9 @@ typedef struct {
     // AhciWorker blocks here waiting for work. AHCI dispatch enqueues an IRP
     // and signals the semaphore to wake the worker.
     IRP_QUEUE       irpQueue;
+    IO_REMOVE_LOCK  removeLock;
+    bool            surpriseRemoved;
+    bool            removed;
     THREAD*         workerThread;
     DEVICE_OBJECT*  deviceObject;