From 140e567fdc3e5c979a395d4ec79294195c979e22 Mon Sep 17 00:00:00 2001
From: Bill Zissimopoulos <billziss@navimatics.com>
Date: Thu, 10 Dec 2015 16:31:01 -0800
Subject: [PATCH] sys: call IoRegisterFileSystem from DriverEntry

---
 src/sys/device.c |  8 ++++++++
 src/sys/driver.c | 14 ++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/src/sys/device.c b/src/sys/device.c
index 0258300c..6c93e748 100644
--- a/src/sys/device.c
+++ b/src/sys/device.c
@@ -289,9 +289,13 @@ VOID FspFsctlDeviceVolumeCreated(PDEVICE_OBJECT DeviceObject)
     ASSERT(FspFsctlDeviceExtensionKind == FspDeviceExtension(DeviceObject)->Kind);
     ASSERT(ExIsResourceAcquiredExclusiveLite(&FspDeviceExtension(DeviceObject)->Resource));
 
+#if 1
+    FspFsctlDeviceExtension(DeviceObject)->FsvrtDeviceObjectCount++;
+#else
     ULONG FsvrtDeviceObjectCount = FspFsctlDeviceExtension(DeviceObject)->FsvrtDeviceObjectCount++;
     if (0 == FsvrtDeviceObjectCount)
         IoRegisterFileSystem(DeviceObject);
+#endif
 }
 
 VOID FspFsctlDeviceVolumeDeleted(PDEVICE_OBJECT DeviceObject)
@@ -301,9 +305,13 @@ VOID FspFsctlDeviceVolumeDeleted(PDEVICE_OBJECT DeviceObject)
     ASSERT(FspFsctlDeviceExtensionKind == FspDeviceExtension(DeviceObject)->Kind);
     ASSERT(ExIsResourceAcquiredExclusiveLite(&FspDeviceExtension(DeviceObject)->Resource));
 
+#if 1
+    --FspFsctlDeviceExtension(DeviceObject)->FsvrtDeviceObjectCount;
+#else
     ULONG FsvrtDeviceObjectCount = --FspFsctlDeviceExtension(DeviceObject)->FsvrtDeviceObjectCount;
     if (0 == FsvrtDeviceObjectCount)
         IoUnregisterFileSystem(DeviceObject);
+#endif
 }
 
 PVOID FspFsvolDeviceLookupContext(PDEVICE_OBJECT DeviceObject, UINT64 Identifier)
diff --git a/src/sys/driver.c b/src/sys/driver.c
index 4e254929..10ae34c1 100644
--- a/src/sys/driver.c
+++ b/src/sys/driver.c
@@ -121,6 +121,20 @@ NTSTATUS DriverEntry(
 #pragma prefast(suppress:28175, "We are a filesystem: ok to access FastIoDispatch")
     DriverObject->FastIoDispatch = &FspFastIoDispatch;
 
+    /*
+     * Register our devices as file systems. We do this here to simplify file system
+     * registration/unregistration, although this makes our driver unloadable from the
+     * get go.
+     *
+     * Unfortunately a call to IoRegisterFileSystem(), even if followed by a call to
+     * IoUnregistreFileSystem(), makes the driver unloadable. We attempted to move
+     * the register/unregister calls to FspFsctlDeviceVolume{Created,Deleted}, but it
+     * did not make any difference with regards to making the driver unloadable. Hence
+     * we stick to the simpler scheme of doing registration here.
+     */
+    IoRegisterFileSystem(FspFsctlDiskDeviceObject);
+    IoRegisterFileSystem(FspFsctlNetDeviceObject);
+
 #pragma prefast(suppress:28175, "We are in DriverEntry: ok to access DriverName")
     FSP_LEAVE("DriverName=\"%wZ\", RegistryPath=\"%wZ\"",
         &DriverObject->DriverName, RegistryPath);