diff --git a/src/sys/driver.h b/src/sys/driver.h
index 973c8ae0..9621edfb 100644
--- a/src/sys/driver.h
+++ b/src/sys/driver.h
@@ -29,6 +29,7 @@
 #include <ntstrsafe.h>
 #include <wdmsec.h>
 #include <winfsp/fsctl.h>
+#include <winfsp/fsext.h>
 
 /* disable warnings */
 #pragma warning(disable:4100)           /* unreferenced formal parameter */
@@ -1085,6 +1086,7 @@ typedef struct
     PNOTIFY_SYNC NotifySync;
     LIST_ENTRY NotifyList;
     FSP_STATISTICS *Statistics;
+    FSP_FSCTL_DECLSPEC_ALIGN UINT8 FsextData[];
 } FSP_FSVOL_DEVICE_EXTENSION;
 typedef struct
 {
@@ -1176,6 +1178,9 @@ VOID FspDeviceGlobalUnlock(VOID)
     //(FILE_DEVICE_DISK_FILE_SYSTEM == (DeviceObject)->DeviceType ?\
     //    STATUS_VOLUME_DISMOUNTED : STATUS_DEVICE_NOT_CONNECTED)
 
+/* fsext */
+FSP_FSEXT_PROVIDER *FspFsextProvider(VOID);
+
 /* process buffers conditional usage */
 static inline
 BOOLEAN FspReadIrpShouldUseProcessBuffer(PIRP Irp, SIZE_T BufferSize)
diff --git a/src/sys/fsext.c b/src/sys/fsext.c
index 58459c1e..1c3e1ce3 100644
--- a/src/sys/fsext.c
+++ b/src/sys/fsext.c
@@ -22,7 +22,37 @@
 #include <sys/driver.h>
 #include <winfsp/fsext.h>
 
+static KSPIN_LOCK FsextSpinLock = 0;
+FSP_FSEXT_PROVIDER *FsextProvider;
+
+FSP_FSEXT_PROVIDER *FspFsextProvider(VOID)
+{
+    FSP_FSEXT_PROVIDER *Provider;
+    KIRQL Irql;
+
+    KeAcquireSpinLock(&FsextSpinLock, &Irql);
+    Provider = FsextProvider;
+    KeReleaseSpinLock(&FsextSpinLock, Irql);
+
+    return Provider;
+}
+
 NTSTATUS FspFsextProviderRegister(FSP_FSEXT_PROVIDER *Provider)
 {
-    return STATUS_TOO_LATE;
+    NTSTATUS Result;
+    KIRQL Irql;
+
+    KeAcquireSpinLock(&FsextSpinLock, &Irql);
+    if (0 != FsextProvider)
+    {
+        Result = STATUS_TOO_LATE;
+        goto exit;
+    }
+    Provider->DeviceExtensionOffset = FIELD_OFFSET(FSP_FSVOL_DEVICE_EXTENSION, FsextData);
+    FsextProvider = Provider;
+    Result = STATUS_SUCCESS;
+exit:
+    KeReleaseSpinLock(&FsextSpinLock, Irql);
+
+    return Result;
 }