build: update version number

Zero out OutputBuffer on error to avoid confusion for fsext providers.

Changelog.asciidoc

@@ -1,5 +1,54 @@
 = Changelog
 
+
+v1.8B2 (2020.2 B2)::
+
+Changes since v1.7:
+
+* [FSD] WinFsp now supports Windows containers. See the link:doc/WinFsp-Container-Support.asciidoc[WinFsp Container Support] document for details.
+
+* [FSD] The `FSP_FSCTL_QUERY_WINFSP` code provides a simple method to determine if
+the file system backing a file is a WinFsp file system. To use issue a
++
+----
+DeviceIoControl(Handle, FSP_FSCTL_QUERY_WINFSP, 0, 0, 0, 0, &Bytes, 0)
+----
++
+If the return value is TRUE this is a WinFsp file system.
+
+* [FSD] A fix regarding concurrency of READs on the same file: WinFsp was supposed to allow concurrent READ requests on the same file (e.g. two concurrent overlapped `ReadFile` requests on the same `HANDLE`) to be handled concurrently by the file system; unfortunately due to a problem in recent versions of WinFsp READ requests on the same file were serialized. This problem has now been fixed. See GitHub issue #291 for more details.
+** *NOTE*: It may be that some file system was inadvertently relying on WinFsp's implicit serialization of READs in this case. Please test your file system thoroughly against this version, especially with regard to READ serialization. Related XKCD: https://imgs.xkcd.com/comics/workflow.png
+
+
+v1.8B1 (2020.2 B1)::
+
+Changes since v1.7:
+
+* [FSD] WinFsp now supports Windows containers. See the link:doc/WinFsp-Container-Support.asciidoc[WinFsp Container Support] document for details.
+* [FSD] The `FSP_FSCTL_QUERY_WINFSP` code provides a simple method to determine if
+the file system backing a file is a WinFsp file system. To use issue a
++
+----
+DeviceIoControl(Handle, FSP_FSCTL_QUERY_WINFSP, 0, 0, 0, 0, &Bytes, 0)
+----
++
+If the return value is TRUE this is a WinFsp file system.
+
+
+v1.7 (2020.1)::
+
+Changes since v1.6:
+
+* [FUSE] FUSE invalid directory entries no longer break the entire directory listing. Such invalid directory entries are logged. (GitHub PR #292.)
+* [LAUNCH] The Launcher can now restart file systems that have crashed. Set `Recovery=1` in the file system's registry entry.
+* [LAUNCH] The Launcher can now redirect file system standard error output. Set `Stderr=PATH` in the file system's registry entry.
+* [FIX] Work around a problem in CreateProcess/CreateSection that allowed a faulty or malicious file system to bugcheck Windows.
+* [FIX] Work around an incompatibility with Avast Antivirus.
+** Native and .NET file systems that experience this problem should set the flag `RejectIrpPriorToTransact0` in `FSP_FSCTL_VOLUME_PARAMS` to `1`. This is only required when mounting on a directory with Avast Antivirus present.
+** FUSE file systems do not need to do anything special as this flag is always enabled.
+* [FIX] Fix junction (mount point reparse point) handling. (GitHub issue #269.)
+
+
 v1.7B2 (2020.1 B2)::
 
 Changes since v1.6:

appveyor.yml

@@ -35,8 +35,8 @@ build_script:
 # build cygfuse
 - C:\cygwin64\setup-x86_64.exe -qnNd -P cygport
 - C:\cygwin64\bin\bash --login -c "make -C '%CD%\opt\cygfuse' dist"
-- C:\cygwin\setup-x86.exe -qnNd -P cygport
-- C:\cygwin\bin\bash --login -c "make -C '%CD%\opt\cygfuse' dist"
+#- C:\cygwin\setup-x86.exe -qnNd -P cygport
+#- C:\cygwin\bin\bash --login -c "make -C '%CD%\opt\cygfuse' dist"
 # build winfsp
 - tools\build.bat %CONFIGURATION%
 

build/VStudio/version.properties

@@ -16,10 +16,10 @@
         <MyCompanyName>Navimatics LLC</MyCompanyName>
         <MyCopyright>2015-$([System.DateTime]::Now.ToString(`yyyy`)) Bill Zissimopoulos</MyCopyright>
 
-        <MyCanonicalVersion>1.7</MyCanonicalVersion>
+        <MyCanonicalVersion>1.8</MyCanonicalVersion>
 
-        <MyProductVersion>2020.1</MyProductVersion>
-        <MyProductStage>Gold</MyProductStage>
+        <MyProductVersion>2020.2 Beta2</MyProductVersion>
+        <MyProductStage>Beta</MyProductStage>
 
         <MyVersion>$(MyCanonicalVersion).$(MyBuildNumber)</MyVersion>
         <MyVersionWithCommas>$(MyVersion.Replace('.',',')),0</MyVersionWithCommas>

build/VStudio/winfsp_sys.vcxproj

@@ -185,6 +185,7 @@
     <ClCompile Include="..\..\src\sys\read.c" />
     <ClCompile Include="..\..\src\sys\security.c" />
     <ClCompile Include="..\..\src\sys\shutdown.c" />
+    <ClCompile Include="..\..\src\sys\silo.c" />
     <ClCompile Include="..\..\src\sys\statistics.c" />
     <ClCompile Include="..\..\src\sys\util.c" />
     <ClCompile Include="..\..\src\sys\volinfo.c" />

build/VStudio/winfsp_sys.vcxproj.filters

@@ -122,6 +122,9 @@
     <ClCompile Include="..\..\src\shared\ku\uuid5.c">
       <Filter>Source\shared\ku</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\sys\silo.c">
+      <Filter>Source</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\src\sys\driver.h">

doc/WinFsp-Container-Support.asciidoc

@@ -0,0 +1,73 @@
+= WinFsp Container Support
+
+WinFsp gained support for Windows Containers in release 2020.2 B1. This document discusses this new functionality and explains how user mode file systems can take advantage of it.
+
+NOTE: WinFsp support for Windows Containers is at this time highly experimental. It may change substantially in the future or eliminated altogether.
+
+== Windows Containers
+
+Containers are a technology for deployment and execution of applications in an isolated environment. Applications deployed inside a container cannot be affected by or affect applications in other containers or in the host operating system.
+
+Containers on Windows provide isolation via one of two modes:
+
+- The _Hyper-V_ isolation mode where a container runs in its own virtual machine and has its own kernel.
+
+- The _process_ isolation mode where a container runs in a "silo" inside the host operating system's kernel. This is the same model used in containers for Linux.
+
+WinFsp supports containers that use the process isolation mode in versions of Windows 10 1809 and later.
+
+=== Server Silos
+
+Containers using the process isolation mode are called _server silos_. Server silos are built on top of kernel job objects that have been extended with additional capabities useful for containers. Most importantly each server silo has its own object namespace root directory that is distinct from the host's object namespace root directory. This allows for all named kernel objects inside a server silo to be isolated from named objects in other server silos or the host.
+
+The Windows kernel provides a number of DDI's (Device Driver Interfaces) to enable kernel drivers to work with server silos. The WinFsp FSD uses these DDI's to monitor silo creation and termination and manage its own devices within the silo's object namespace.
+
+=== Docker
+
+In order to manage containers on Windows a version of Docker for Windows is needed. In order to use server silos and process isolation with Docker the switch `--isolation=process` must be used when creating a container:
+
+----
+docker run --isolation=process ...
+----
+
+== Containerized User Mode File Systems
+
+The WinFsp 2020.2 B1 release gained the ability for user mode file systems to run inside a server silo container and expose a file system either within the container or to the host operating system. This allows for user mode file systems to be containerized.
+
+There are a few considerations that must be taken into account when deploying a user mode file system in a container:
+
+* When using WinFsp with containers the process isolation mode must be used.
+
+* WinFsp currently supports the Windows Server Core and Windows base images. Work is underway for Nano Server compatibility.
+
+* User mode file systems that run in a container cannot start the FSD, because containers disallow driver loading. (Usually the WinFsp DLL automatically starts the WinFsp FSD when it is not already running, but this is not possible within a container.)
++
+To work around this problem start the FSD outside the container. For example, the FSD can be started in the host using the `sc.exe` utility.
++
+----
+sc.exe start winfsp
+----
++
+Once the FSD has been started it will monitor server silo creation and termination and will set things up so that containerized user mode file systems will be able to interface with it.
+
+* WinFsp file systems typically use the registry to locate and load the WinFsp DLL (see `FspLoad` in `winfsp/winfsp.h`). However the registry inside a container does not contain any WinFsp entries. The easiest workaround is to hardcode the location of the WinFsp installation within the container, which will also hardcode the location of the WinFsp DLL.
+
+* During development it is sometimes useful to bind mount the WinFsp installation directory into the container. For example:
++
+----
+docker run -it --rm --isolation=process "-vC:\Program Files (x86)\WinFsp:C:\Program Files (x86)\WinFsp:RO" mcr.microsoft.com/windows/servercore:2004 cmd.exe
+----
+
+* When a WinFsp based file system is mounted as a disk file system within a container, it is only visible within that container. For example, the drive `Z:` below and associated file system volume will be accessible only within the container:
++
+----
+memfs-x64 -i -F NTFS -m Z:
+----
+
+* When a WinFsp based file system is mounted as a network file system within a container, the file system becomes accessible **outside** the container via its UNC prefix. For example, while the drive `Y:` below will be accessible only within the container, the file system volume will be accessible from both the container and the host via the UNC prefix `\\memfs\share`.
++
+----
+memfs-x64 -i -F NTFS -m Y: -u \memfs\share
+----
++
+The reason that this happens is that server silo containers share the same MUP device object with the host. The MUP (Multiple UNC Provider) is the Windows kernel component responsible for resolving UNC prefixes. It is unclear at this time whether this "leak" from the container to the host via the shared MUP is intentional or whether it is an unintended consequence. I note that the server silo MUP entry in the object namespace is a symbolic link, which suggests that the shared MUP device object was a conscious decision by Microsoft.

inc/winfsp/fsctl.h

@@ -71,6 +71,10 @@ extern const __declspec(selectany) GUID FspFsvrtDeviceClassGuid =
 #define FSP_FSCTL_TRANSACT_INTERNAL     \
     CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 0x800 + 'I', METHOD_NEITHER, FILE_ANY_ACCESS)
 
+/* fsvol device codes */
+#define FSP_FSCTL_QUERY_WINFSP          \
+    CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 0x800 + '?', METHOD_BUFFERED, FILE_ANY_ACCESS)
+
 #define FSP_FSCTL_VOLUME_PARAMS_PREFIX  "\\VolumeParams="
 
 #define FSP_FSCTL_VOLUME_NAME_SIZE      (64 * sizeof(WCHAR))

src/dll/fsctl.c

@@ -242,6 +242,22 @@ static NTSTATUS FspFsctlStartService(VOID)
     DWORD LastError;
     NTSTATUS Result;
 
+    /* Determine if we are running inside container.
+     *
+     * See https://github.com/microsoft/perfview/blob/V1.9.65/src/TraceEvent/TraceEventSession.cs#L525
+     * See https://stackoverflow.com/a/50748300
+     */
+    LastError = RegGetValueW(
+        HKEY_LOCAL_MACHINE, L"SYSTEM\\CurrentControlSet\\Control",
+        L"ContainerType",
+        RRF_RT_REG_DWORD, 0,
+        0, 0);
+    if (ERROR_SUCCESS == LastError)
+    {
+        Result = STATUS_SUCCESS;
+        goto exit;
+    }
+
     ScmHandle = OpenSCManagerW(0, 0, 0);
     if (0 == ScmHandle)
     {

src/sys/driver.c

@@ -21,26 +21,16 @@
 
 #include <sys/driver.h>
 
-/*
- * Define the following macro to include FspUnload.
- *
- * Note that this driver is no longer unloadable.
- * See the comments in DriverEntry as to why!
- */
-//#define FSP_UNLOAD
-
 DRIVER_INITIALIZE DriverEntry;
 static VOID FspDriverMultiVersionInitialize(VOID);
-#if defined(FSP_UNLOAD)
-DRIVER_UNLOAD FspUnload;
-#endif
+static NTSTATUS FspDriverInitializeDevices(VOID);
+static VOID FspDriverFinalizeDevices(VOID);
 
 #ifdef ALLOC_PRAGMA
 #pragma alloc_text(INIT, DriverEntry)
 #pragma alloc_text(INIT, FspDriverMultiVersionInitialize)
-#if defined(FSP_UNLOAD)
-#pragma alloc_text(PAGE, FspUnload)
-#endif
+#pragma alloc_text(PAGE, FspDriverInitializeDevices)
+#pragma alloc_text(PAGE, FspDriverFinalizeDevices)
 #endif
 
 NTSTATUS DriverEntry(
@@ -49,9 +39,6 @@ NTSTATUS DriverEntry(
     FSP_ENTER_DRV();
 
     /* setup the driver object */
-#if defined(FSP_UNLOAD)
-    DriverObject->DriverUnload = FspUnload;
-#endif
     DriverObject->MajorFunction[IRP_MJ_CREATE] = FspCreate;
     DriverObject->MajorFunction[IRP_MJ_CLOSE] = FspClose;
     DriverObject->MajorFunction[IRP_MJ_READ] = FspRead;
@@ -133,94 +120,41 @@ NTSTATUS DriverEntry(
 #pragma prefast(suppress:28175, "We are a filesystem: ok to access FastIoDispatch")
     DriverObject->FastIoDispatch = &FspFastIoDispatch;
 
-    BOOLEAN InitDoneGRes = FALSE, InitDonePsBuf = FALSE;
-    UNICODE_STRING DeviceSddl;
-    UNICODE_STRING DeviceName;
+    BOOLEAN InitDoneGRes = FALSE, InitDoneSilo = FALSE, InitDonePsBuf = FALSE,
+        InitDoneDevices = FALSE;
 
     FspDriverObject = DriverObject;
+    FspDriverMultiVersionInitialize();
+
     ExInitializeResourceLite(&FspDeviceGlobalResource);
     InitDoneGRes = TRUE;
 
-    FspDriverMultiVersionInitialize();
+    Result = FspSiloInitialize(FspDriverInitializeDevices, FspDriverFinalizeDevices);
+    if (!NT_SUCCESS(Result))
+        goto exit;
+    InitDoneSilo = TRUE;
 
     Result = FspProcessBufferInitialize();
     if (!NT_SUCCESS(Result))
         goto exit;
     InitDonePsBuf = TRUE;
 
-    /* create the file system control device objects */
-    RtlInitUnicodeString(&DeviceSddl, L"" FSP_FSCTL_DEVICE_SDDL);
-    RtlInitUnicodeString(&DeviceName, L"\\Device\\" FSP_FSCTL_DISK_DEVICE_NAME);
-    Result = FspDeviceCreateSecure(FspFsctlDeviceExtensionKind, 0,
-        &DeviceName, FILE_DEVICE_DISK_FILE_SYSTEM, FILE_DEVICE_SECURE_OPEN,
-        &DeviceSddl, &FspFsctlDeviceClassGuid,
-        &FspFsctlDiskDeviceObject);
+    Result = FspDriverInitializeDevices();
     if (!NT_SUCCESS(Result))
         goto exit;
-    RtlInitUnicodeString(&DeviceName, L"\\Device\\" FSP_FSCTL_NET_DEVICE_NAME);
-    Result = FspDeviceCreateSecure(FspFsctlDeviceExtensionKind, 0,
-        &DeviceName, FILE_DEVICE_NETWORK_FILE_SYSTEM, FILE_DEVICE_SECURE_OPEN,
-        &DeviceSddl, &FspFsctlDeviceClassGuid,
-        &FspFsctlNetDeviceObject);
-    if (!NT_SUCCESS(Result))
-        goto exit;
-    Result = FspDeviceCreate(FspFsmupDeviceExtensionKind, 0,
-        FILE_DEVICE_NETWORK_FILE_SYSTEM, FILE_REMOTE_DEVICE,
-        &FspFsmupDeviceObject);
-    if (!NT_SUCCESS(Result))
-        goto exit;
-
-#if DBG
-    /*
-     * Fix GitHub issue #177. All credit for the investigation of this issue
-     * and the suggested steps to reproduce and work around the problem goes
-     * to GitHub user @thinkport.
-     *
-     * On debug builds set DO_LOW_PRIORITY_FILESYSTEM to place the file system
-     * at the end of the file system list during IoRegisterFileSystem below.
-     * This allows us to test the behavior of our Fsvrt devices when foreign
-     * file systems attempt to use them for mounting.
-     */
-    SetFlag(FspFsctlDiskDeviceObject->Flags, DO_LOW_PRIORITY_FILESYSTEM);
-#endif
-
-    Result = FspDeviceInitialize(FspFsctlDiskDeviceObject);
-    ASSERT(STATUS_SUCCESS == Result);
-    Result = FspDeviceInitialize(FspFsctlNetDeviceObject);
-    ASSERT(STATUS_SUCCESS == Result);
-    Result = FspDeviceInitialize(FspFsmupDeviceObject);
-    ASSERT(STATUS_SUCCESS == Result);
-
-    RtlInitUnicodeString(&DeviceName, L"\\Device\\" FSP_FSCTL_MUP_DEVICE_NAME);
-    Result = FsRtlRegisterUncProviderEx(&FspMupHandle,
-        &DeviceName, FspFsmupDeviceObject, 0);
-    if (!NT_SUCCESS(Result))
-        goto exit;
-
-    /*
-     * Register our "disk" device as a file system. We do not register our "net" device
-     * as a file system; we register with the MUP instead.
-     *
-     * Please note that the call below makes our driver unloadable. In fact the driver
-     * remains unloadable even if we issue an IoUnregisterFileSystem() call immediately
-     * after our IoRegisterFileSystem() call! Some system component appears to keep an
-     * extra reference to our device somewhere.
-     */
-    IoRegisterFileSystem(FspFsctlDiskDeviceObject);
+    InitDoneDevices = TRUE;
 
     Result = STATUS_SUCCESS;
 
 exit:
     if (!NT_SUCCESS(Result))
     {
-        if (0 != FspFsmupDeviceObject)
-            FspDeviceDelete(FspFsmupDeviceObject);
-        if (0 != FspFsctlNetDeviceObject)
-            FspDeviceDelete(FspFsctlNetDeviceObject);
-        if (0 != FspFsctlDiskDeviceObject)
-            FspDeviceDelete(FspFsctlDiskDeviceObject);
+        if (InitDoneDevices)
+            FspDriverFinalizeDevices();
         if (InitDonePsBuf)
             FspProcessBufferFinalize();
+        if (InitDoneSilo)
+            FspSiloFinalize();
         if (InitDoneGRes)
             ExDeleteResourceLite(&FspDeviceGlobalResource);
     }
@@ -237,7 +171,7 @@ static VOID FspDriverMultiVersionInitialize(VOID)
 #pragma prefast(suppress:30035, "FspDriverMultiVersionInitialize is called from DriverEntry")
     ExInitializeDriverRuntime(DrvRtPoolNxOptIn);
 
-    if (RtlIsNtDdiVersionAvailable(NTDDI_WIN7))
+    if (FspIsNtDdiVersionAvailable(NTDDI_WIN7))
     {
         UNICODE_STRING Name;
 
@@ -246,42 +180,164 @@ static VOID FspDriverMultiVersionInitialize(VOID)
             (FSP_MV_CcCoherencyFlushAndPurgeCache *)(UINT_PTR)MmGetSystemRoutineAddress(&Name);
     }
 
-    if (RtlIsNtDdiVersionAvailable(NTDDI_WIN8))
+    if (FspIsNtDdiVersionAvailable(NTDDI_WIN8))
         FspMvMdlMappingNoWrite = MdlMappingNoWrite;
 
-    if (RtlIsNtDdiVersionAvailable(0x0A000005/*NTDDI_WIN10_RS4*/))
+    if (FspIsNtDdiVersionAvailable(NTDDI_WIN10_RS4))
         FspHasReparsePointCaseSensitivityFix = TRUE;
 }
 
-#if defined(FSP_UNLOAD)
-VOID FspUnload(
-    PDRIVER_OBJECT DriverObject)
+static NTSTATUS FspDriverInitializeDevices(VOID)
 {
-    FSP_ENTER_VOID(PAGED_CODE());
+    PAGED_CODE();
 
-    FsRtlDeregisterUncProvider(FspMupHandle);
+    FSP_SILO_GLOBALS *Globals;
+    UNICODE_STRING DeviceSddl;
+    UNICODE_STRING DeviceName;
+    GUID Guid;
+    NTSTATUS Result;
 
-    FspFsctlDiskDeviceObject = 0;
-    FspFsctlNetDeviceObject = 0;
-    FspFsmupDeviceObject = 0;
-    //FspDeviceDeleteAll();
+    FspSiloGetGlobals(&Globals);
+    ASSERT(0 != Globals);
 
-    ExDeleteResourceLite(&FspDeviceGlobalResource);
-    FspDriverObject = 0;
+    /* create the file system control device objects */
+    RtlInitUnicodeString(&DeviceSddl, L"" FSP_FSCTL_DEVICE_SDDL);
+    RtlInitUnicodeString(&DeviceName, L"\\Device\\" FSP_FSCTL_DISK_DEVICE_NAME);
+    Result = FspDeviceCreateSecure(FspFsctlDeviceExtensionKind, 0,
+        &DeviceName, FILE_DEVICE_DISK_FILE_SYSTEM, FILE_DEVICE_SECURE_OPEN,
+        &DeviceSddl, &FspFsctlDeviceClassGuid,
+        &Globals->FsctlDiskDeviceObject);
+    if (!NT_SUCCESS(Result))
+        goto exit;
+    RtlInitUnicodeString(&DeviceName, L"\\Device\\" FSP_FSCTL_NET_DEVICE_NAME);
+    Result = FspDeviceCreateSecure(FspFsctlDeviceExtensionKind, 0,
+        &DeviceName, FILE_DEVICE_NETWORK_FILE_SYSTEM, FILE_DEVICE_SECURE_OPEN,
+        &DeviceSddl, &FspFsctlDeviceClassGuid,
+        &Globals->FsctlNetDeviceObject);
+    if (!NT_SUCCESS(Result))
+        goto exit;
+    Result = FspDeviceCreate(FspFsmupDeviceExtensionKind, 0,
+        FILE_DEVICE_NETWORK_FILE_SYSTEM, FILE_REMOTE_DEVICE,
+        &Globals->FsmupDeviceObject);
+    if (!NT_SUCCESS(Result))
+        goto exit;
 
-    FspProcessBufferFinalize();
-
-#pragma prefast(suppress:28175, "We are in DriverUnload: ok to access DriverName")
-    FSP_LEAVE_VOID("DriverName=\"%wZ\"",
-        &DriverObject->DriverName);
-}
+#if DBG
+    /*
+     * Fix GitHub issue #177. All credit for the investigation of this issue
+     * and the suggested steps to reproduce and work around the problem goes
+     * to GitHub user @thinkport.
+     *
+     * On debug builds set DO_LOW_PRIORITY_FILESYSTEM to place the file system
+     * at the end of the file system list during IoRegisterFileSystem below.
+     * This allows us to test the behavior of our Fsvrt devices when foreign
+     * file systems attempt to use them for mounting.
+     */
+    SetFlag(Globals->FsctlDiskDeviceObject->Flags, DO_LOW_PRIORITY_FILESYSTEM);
 #endif
 
+    Result = FspDeviceInitialize(Globals->FsctlDiskDeviceObject);
+    ASSERT(STATUS_SUCCESS == Result);
+    Result = FspDeviceInitialize(Globals->FsctlNetDeviceObject);
+    ASSERT(STATUS_SUCCESS == Result);
+    Result = FspDeviceInitialize(Globals->FsmupDeviceObject);
+    ASSERT(STATUS_SUCCESS == Result);
+
+    FspSiloGetContainerId(&Guid);
+    RtlInitEmptyUnicodeString(&DeviceName,
+        Globals->FsmupDeviceNameBuf, sizeof Globals->FsmupDeviceNameBuf);
+    Result = RtlUnicodeStringPrintf(&DeviceName,
+        0 == ((PULONG)&Guid)[0] && 0 == ((PULONG)&Guid)[1] &&
+        0 == ((PULONG)&Guid)[2] && 0 == ((PULONG)&Guid)[3] ?
+            L"\\Device\\" FSP_FSCTL_MUP_DEVICE_NAME :
+            L"\\Device\\" FSP_FSCTL_MUP_DEVICE_NAME "{%08lx-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x}",
+        Guid.Data1, Guid.Data2, Guid.Data3,
+        Guid.Data4[0], Guid.Data4[1], Guid.Data4[2], Guid.Data4[3],
+        Guid.Data4[4], Guid.Data4[5], Guid.Data4[6], Guid.Data4[7]);
+    ASSERT(NT_SUCCESS(Result));
+    DeviceName.MaximumLength = DeviceName.Length;
+    Result = FsRtlRegisterUncProviderEx(&Globals->MupHandle,
+        &DeviceName, Globals->FsmupDeviceObject, 0);
+    if (!NT_SUCCESS(Result))
+    {
+        Globals->MupHandle = 0;
+        goto exit;
+    }
+
+    /*
+     * Register our "disk" device as a file system. We do not register our "net" device
+     * as a file system; we register with the MUP instead.
+     */
+    IoRegisterFileSystem(Globals->FsctlDiskDeviceObject);
+
+    Result = STATUS_SUCCESS;
+
+exit:
+    if (!NT_SUCCESS(Result))
+    {
+        if (0 != Globals->MupHandle)
+        {
+            FsRtlDeregisterUncProvider(Globals->MupHandle);
+            Globals->MupHandle = 0;
+        }
+        if (0 != Globals->FsmupDeviceObject)
+        {
+            FspDeviceDelete(Globals->FsmupDeviceObject);
+            Globals->FsmupDeviceObject = 0;
+        }
+        if (0 != Globals->FsctlNetDeviceObject)
+        {
+            FspDeviceDelete(Globals->FsctlNetDeviceObject);
+            Globals->FsctlNetDeviceObject = 0;
+        }
+        if (0 != Globals->FsctlDiskDeviceObject)
+        {
+            FspDeviceDelete(Globals->FsctlDiskDeviceObject);
+            Globals->FsctlDiskDeviceObject = 0;
+        }
+    }
+
+    FspSiloDereferenceGlobals(Globals);
+
+    return Result;
+}
+
+static VOID FspDriverFinalizeDevices(VOID)
+{
+    PAGED_CODE();
+
+    FSP_SILO_GLOBALS *Globals;
+
+    FspSiloGetGlobals(&Globals);
+    ASSERT(0 != Globals);
+
+    IoUnregisterFileSystem(Globals->FsctlDiskDeviceObject);
+
+    if (0 != Globals->MupHandle)
+    {
+        FsRtlDeregisterUncProvider(Globals->MupHandle);
+        Globals->MupHandle = 0;
+    }
+    if (0 != Globals->FsmupDeviceObject)
+    {
+        FspDeviceDelete(Globals->FsmupDeviceObject);
+        Globals->FsmupDeviceObject = 0;
+    }
+    if (0 != Globals->FsctlNetDeviceObject)
+    {
+        FspDeviceDelete(Globals->FsctlNetDeviceObject);
+        Globals->FsctlNetDeviceObject = 0;
+    }
+    if (0 != Globals->FsctlDiskDeviceObject)
+    {
+        FspDeviceDelete(Globals->FsctlDiskDeviceObject);
+        Globals->FsctlDiskDeviceObject = 0;
+    }
+
+    FspSiloDereferenceGlobals(Globals);
+}
+
 PDRIVER_OBJECT FspDriverObject;
-PDEVICE_OBJECT FspFsctlDiskDeviceObject;
-PDEVICE_OBJECT FspFsctlNetDeviceObject;
-PDEVICE_OBJECT FspFsmupDeviceObject;
-HANDLE FspMupHandle;
 FAST_IO_DISPATCH FspFastIoDispatch;
 CACHE_MANAGER_CALLBACKS FspCacheManagerCallbacks;
 

src/sys/driver.h

@@ -503,6 +503,7 @@ NTSTATUS FspUuid5Make(const UUID *Namespace, const VOID *Buffer, ULONG Size, UUI
 /* utility */
 PVOID FspAllocatePoolMustSucceed(POOL_TYPE PoolType, SIZE_T Size, ULONG Tag);
 PVOID FspAllocateIrpMustSucceed(CCHAR StackSize);
+BOOLEAN FspIsNtDdiVersionAvailable(ULONG RequestedVersion);
 NTSTATUS FspCreateGuid(GUID *Guid);
 NTSTATUS FspGetDeviceObjectPointer(PUNICODE_STRING ObjectName, ACCESS_MASK DesiredAccess,
     PULONG PFileNameIndex, PFILE_OBJECT *PFileObject, PDEVICE_OBJECT *PDeviceObject);
@@ -651,6 +652,23 @@ VOID FspIrpHookReset(PIRP Irp);
 PVOID FspIrpHookContext(PVOID Context);
 NTSTATUS FspIrpHookNext(PDEVICE_OBJECT DeviceObject, PIRP Irp, PVOID Context);
 
+/* silos */
+typedef struct
+{
+    PDEVICE_OBJECT FsctlDiskDeviceObject;
+    PDEVICE_OBJECT FsctlNetDeviceObject;
+    PDEVICE_OBJECT FsmupDeviceObject;
+    HANDLE MupHandle;
+    WCHAR FsmupDeviceNameBuf[64];
+} FSP_SILO_GLOBALS;
+typedef NTSTATUS (*FSP_SILO_INIT_CALLBACK)(VOID);
+typedef VOID (*FSP_SILO_FINI_CALLBACK)(VOID);
+NTSTATUS FspSiloGetGlobals(FSP_SILO_GLOBALS **PGlobals);
+VOID FspSiloDereferenceGlobals(FSP_SILO_GLOBALS *Globals);
+VOID FspSiloGetContainerId(GUID *ContainerId);
+NTSTATUS FspSiloInitialize(FSP_SILO_INIT_CALLBACK Init, FSP_SILO_FINI_CALLBACK Fini);
+VOID FspSiloFinalize(VOID);
+
 /* process buffers */
 #define FspProcessBufferSizeMax         (64 * 1024)
 NTSTATUS FspProcessBufferInitialize(VOID);
@@ -1068,6 +1086,7 @@ typedef struct
     KSPIN_LOCK SpinLock;
     LONG RefCount;
     UINT32 Kind;
+    GUID SiloContainerId;
 } FSP_DEVICE_EXTENSION;
 typedef struct
 {
@@ -1694,10 +1713,6 @@ FSP_MV_CcCoherencyFlushAndPurgeCache(
 
 /* extern */
 extern PDRIVER_OBJECT FspDriverObject;
-extern PDEVICE_OBJECT FspFsctlDiskDeviceObject;
-extern PDEVICE_OBJECT FspFsctlNetDeviceObject;
-extern PDEVICE_OBJECT FspFsmupDeviceObject;
-extern HANDLE FspMupHandle;
 extern FAST_IO_DISPATCH FspFastIoDispatch;
 extern CACHE_MANAGER_CALLBACKS FspCacheManagerCallbacks;
 extern FSP_IOPREP_DISPATCH *FspIopPrepareFunction[];

src/sys/fsctl.c

@@ -698,6 +698,10 @@ static NTSTATUS FspFsvolFileSystemControl(
         case FSP_FSCTL_WORK_BEST_EFFORT:
             Result = FspVolumeWork(FsvolDeviceObject, Irp, IrpSp);
             break;
+        case FSP_FSCTL_QUERY_WINFSP:
+            Irp->IoStatus.Information = 0;
+            Result = STATUS_SUCCESS;
+            break;
         case FSCTL_GET_REPARSE_POINT:
             Result = FspFsvolFileSystemControlReparsePoint(FsvolDeviceObject, Irp, IrpSp, FALSE);
             break;

src/sys/read.c

@@ -249,9 +249,9 @@ static NTSTATUS FspFsvolReadNonCached(
     if (!NT_SUCCESS(Result))
         return Result;
 
-    /* acquire FileNode exclusive Full */
+    /* acquire FileNode shared Full */
     Success = DEBUGTEST(90) &&
-        FspFileNodeTryAcquireExclusiveF(FileNode, FspFileNodeAcquireFull, CanWait);
+        FspFileNodeTryAcquireSharedF(FileNode, FspFileNodeAcquireFull, CanWait);
     if (!Success)
         return FspWqRepostIrpWorkItem(Irp, FspFsvolReadNonCached, 0);
 
@@ -280,21 +280,21 @@ static NTSTATUS FspFsvolReadNonCached(
     /* if this is a non-cached transfer on a cached file then flush the file */
     if (!PagingIo && 0 != FileObject->SectionObjectPointer->DataSectionObject)
     {
+        FspFileNodeRelease(FileNode, Full);
         if (!CanWait)
-        {
-            FspFileNodeRelease(FileNode, Full);
             return FspWqRepostIrpWorkItem(Irp, FspFsvolReadNonCached, 0);
-        }
 
+        /* need to acquire exclusive for flushing */
+        FspFileNodeAcquireExclusive(FileNode, Full);
         Result = FspFileNodeFlushAndPurgeCache(FileNode,
             IrpSp->Parameters.Read.ByteOffset.QuadPart,
             IrpSp->Parameters.Read.Length,
             FALSE);
+        FspFileNodeRelease(FileNode, Full);
         if (!NT_SUCCESS(Result))
-        {
-            FspFileNodeRelease(FileNode, Full);
             return Result;
-        }
+
+        FspFileNodeAcquireShared(FileNode, Full);
     }
 
     /* trim ReadLength during CreateProcess; resolve bugcheck for filesystem that reports incorrect size */
@@ -310,9 +310,6 @@ static NTSTATUS FspFsvolReadNonCached(
             ReadLength = (ULONG)(FileInfo.FileSize - ReadOffset.QuadPart);
     }
 
-    /* convert FileNode to shared */
-    FspFileNodeConvertExclusiveToShared(FileNode, Full);
-
     Request = FspIrpRequest(Irp);
     if (0 == Request)
     {

src/sys/silo.c

@@ -0,0 +1,325 @@
+/**
+ * @file sys/silo.c
+ *
+ * @copyright 2015-2020 Bill Zissimopoulos
+ */
+/*
+ * This file is part of WinFsp.
+ *
+ * You can redistribute it and/or modify it under the terms of the GNU
+ * General Public License version 3 as published by the Free Software
+ * Foundation.
+ *
+ * Licensees holding a valid commercial license may use this software
+ * in accordance with the commercial license agreement provided in
+ * conjunction with the software.  The terms and conditions of any such
+ * commercial license agreement shall govern, supersede, and render
+ * ineffective any application of the GPLv3 license to this software,
+ * notwithstanding of any reference thereto in the software or
+ * associated repository.
+ */
+
+#include <sys/driver.h>
+
+NTSTATUS FspSiloInitialize(FSP_SILO_INIT_CALLBACK Init, FSP_SILO_FINI_CALLBACK Fini);
+
+#ifdef ALLOC_PRAGMA
+#pragma alloc_text(INIT, FspSiloInitialize)
+#endif
+
+typedef PEJOB FSP_PESILO;
+typedef PVOID FSP_PSILO_MONITOR;
+
+typedef NTSTATUS (NTAPI *FSP_SILO_MONITOR_CREATE_CALLBACK)(FSP_PESILO Silo);
+typedef VOID (NTAPI *FSP_SILO_MONITOR_TERMINATE_CALLBACK)(FSP_PESILO Silo);
+typedef VOID (NTAPI *FSP_SILO_CONTEXT_CLEANUP_CALLBACK)(PVOID SiloContext);
+
+#pragma warning(push)
+#pragma warning(disable:4201)           /* nameless struct/union */
+typedef struct _FSP_SILO_MONITOR_REGISTRATION
+{
+    UCHAR Version;
+    BOOLEAN MonitorHost;
+    BOOLEAN MonitorExistingSilos;
+    UCHAR Reserved[5];
+    union
+    {
+        PUNICODE_STRING DriverObjectName;
+        PUNICODE_STRING ComponentName;
+    };
+    FSP_SILO_MONITOR_CREATE_CALLBACK CreateCallback;
+    FSP_SILO_MONITOR_TERMINATE_CALLBACK TerminateCallback;
+} FSP_SILO_MONITOR_REGISTRATION;
+#pragma warning(pop)
+
+typedef NTSTATUS FSP_SILO_PsRegisterSiloMonitor(
+    FSP_SILO_MONITOR_REGISTRATION *Registration,
+    FSP_PSILO_MONITOR *ReturnedMonitor);
+typedef NTSTATUS FSP_SILO_PsStartSiloMonitor(
+    FSP_PSILO_MONITOR Monitor);
+typedef VOID FSP_SILO_PsUnregisterSiloMonitor(
+    FSP_PSILO_MONITOR Monitor);
+typedef ULONG FSP_SILO_PsGetSiloMonitorContextSlot(
+    FSP_PSILO_MONITOR Monitor);
+typedef NTSTATUS FSP_SILO_PsCreateSiloContext(
+    FSP_PESILO Silo,
+    ULONG Size,
+    POOL_TYPE PoolType,
+    FSP_SILO_CONTEXT_CLEANUP_CALLBACK ContextCleanupCallback,
+    PVOID *ReturnedSiloContext);
+typedef VOID FSP_SILO_PsDereferenceSiloContext(
+    PVOID SiloContext);
+typedef NTSTATUS FSP_SILO_PsInsertSiloContext(
+    FSP_PESILO Silo,
+    ULONG ContextSlot,
+    PVOID SiloContext);
+typedef NTSTATUS FSP_SILO_PsRemoveSiloContext(
+    FSP_PESILO Silo,
+    ULONG ContextSlot,
+    PVOID *RemovedSiloContext);
+typedef NTSTATUS FSP_SILO_PsGetSiloContext(
+    FSP_PESILO Silo,
+    ULONG ContextSlot,
+    PVOID *ReturnedSiloContext);
+typedef FSP_PESILO FSP_SILO_PsAttachSiloToCurrentThread(
+    FSP_PESILO Silo);
+typedef VOID FSP_SILO_PsDetachSiloFromCurrentThread(
+    FSP_PESILO PreviousSilo);
+typedef FSP_PESILO FSP_SILO_PsGetCurrentServerSilo(
+    VOID);
+typedef GUID* FSP_SILO_PsGetSiloContainerId(
+    FSP_PESILO Silo);
+
+static FSP_SILO_PsRegisterSiloMonitor *FspSiloPsRegisterSiloMonitor;
+static FSP_SILO_PsStartSiloMonitor *FspSiloPsStartSiloMonitor;
+static FSP_SILO_PsUnregisterSiloMonitor *FspSiloPsUnregisterSiloMonitor;
+static FSP_SILO_PsGetSiloMonitorContextSlot *FspSiloPsGetSiloMonitorContextSlot;
+static FSP_SILO_PsCreateSiloContext *FspSiloPsCreateSiloContext;
+static FSP_SILO_PsDereferenceSiloContext *FspSiloPsDereferenceSiloContext;
+static FSP_SILO_PsInsertSiloContext *FspSiloPsInsertSiloContext;
+static FSP_SILO_PsRemoveSiloContext *FspSiloPsRemoveSiloContext;
+static FSP_SILO_PsGetSiloContext *FspSiloPsGetSiloContext;
+static FSP_SILO_PsAttachSiloToCurrentThread *FspSiloPsAttachSiloToCurrentThread;
+static FSP_SILO_PsDetachSiloFromCurrentThread *FspSiloPsDetachSiloFromCurrentThread;
+static FSP_SILO_PsGetCurrentServerSilo *FspSiloPsGetCurrentServerSilo;
+static FSP_SILO_PsGetSiloContainerId *FspSiloPsGetSiloContainerId;
+static FSP_PSILO_MONITOR FspSiloMonitor;
+static FSP_SILO_INIT_CALLBACK FspSiloInitCallback;
+static FSP_SILO_FINI_CALLBACK FspSiloFiniCallback;
+static BOOLEAN FspSiloInitDone = FALSE;
+
+static FSP_SILO_GLOBALS FspSiloHostGlobals;
+
+#define FSP_SILO_MONITOR_REGISTRATION_VERSION 1
+
+#define LOAD(n)                         \
+    {                                   \
+        UNICODE_STRING Name;            \
+        RtlInitUnicodeString(&Name, L"" #n);\
+        FspSilo ## n =                  \
+            (FSP_SILO_ ## n *)(UINT_PTR)MmGetSystemRoutineAddress(&Name);\
+        if (0 == FspSilo ## n)          \
+            Fail++;                     \
+    }
+#define CALL(n)                         (FspSilo ## n)
+
+NTSTATUS FspSiloGetGlobals(FSP_SILO_GLOBALS **PGlobals)
+{
+    FSP_PESILO Silo;
+    ULONG ContextSlot;
+    FSP_SILO_GLOBALS *Globals;
+    NTSTATUS Result;
+
+    if (!FspSiloInitDone ||
+        0 == (Silo = CALL(PsGetCurrentServerSilo)()))
+    {
+        *PGlobals = &FspSiloHostGlobals;
+        return STATUS_SUCCESS;
+    }
+
+    ContextSlot = CALL(PsGetSiloMonitorContextSlot)(FspSiloMonitor);
+
+    Result = CALL(PsGetSiloContext)(Silo, ContextSlot, &Globals);
+    if (!NT_SUCCESS(Result))
+    {
+        *PGlobals = 0;
+        return Result;
+    }
+
+    *PGlobals = Globals;
+    return STATUS_SUCCESS;
+}
+
+VOID FspSiloDereferenceGlobals(FSP_SILO_GLOBALS *Globals)
+{
+    if (&FspSiloHostGlobals == Globals)
+        return;
+
+    CALL(PsDereferenceSiloContext)(Globals);
+}
+
+VOID FspSiloGetContainerId(GUID *ContainerId)
+{
+    FSP_PESILO Silo;
+    GUID *Guid;
+
+    if (!FspSiloInitDone ||
+        0 == (Silo = CALL(PsGetCurrentServerSilo)()) ||
+        0 == (Guid = CALL(PsGetSiloContainerId)(Silo)))
+    {
+        RtlZeroMemory(ContainerId, sizeof *ContainerId);
+        return;
+    }
+
+    RtlCopyMemory(ContainerId, Guid, sizeof *ContainerId);
+}
+
+static NTSTATUS NTAPI FspSiloMonitorCreateCallback(FSP_PESILO Silo)
+{
+    ULONG ContextSlot;
+    FSP_SILO_GLOBALS *Globals = 0;
+    BOOLEAN Inserted = FALSE;
+    NTSTATUS Result;
+
+    ASSERT(0 != Silo);
+
+    ContextSlot = CALL(PsGetSiloMonitorContextSlot)(FspSiloMonitor);
+
+    Result = CALL(PsCreateSiloContext)(Silo, sizeof(FSP_SILO_GLOBALS), NonPagedPoolNx, 0, &Globals);
+    if (!NT_SUCCESS(Result))
+        goto exit;
+    RtlZeroMemory(Globals, sizeof(FSP_SILO_GLOBALS));
+
+    /* PsInsertSiloContext adds reference to Globals */
+    Result = CALL(PsInsertSiloContext)(Silo, ContextSlot, Globals);
+    if (!NT_SUCCESS(Result))
+        goto exit;
+    Inserted = TRUE;
+
+    if (0 != FspSiloInitCallback)
+    {
+        FSP_PESILO PreviousSilo = CALL(PsAttachSiloToCurrentThread)(Silo);
+        Result = FspSiloInitCallback();
+        CALL(PsDetachSiloFromCurrentThread)(PreviousSilo);
+    }
+
+exit:
+    if (!NT_SUCCESS(Result))
+    {
+        if (Inserted)
+            CALL(PsRemoveSiloContext)(Silo, ContextSlot, 0);
+    }
+
+    if (0 != Globals)
+        CALL(PsDereferenceSiloContext)(Globals);
+
+    /*
+     * Ignore errors and return success. There are two reasons for this:
+     *
+     * - Returning an error will disallow container creation.
+     * - In some cases returning an error will crash Windows with an
+     *   unexpected page fault in wcifs.sys.
+     */
+    return STATUS_SUCCESS;
+}
+
+static VOID NTAPI FspSiloMonitorTerminateCallback(FSP_PESILO Silo)
+{
+    ULONG ContextSlot;
+    FSP_SILO_GLOBALS *Globals;
+    NTSTATUS Result;
+
+    ASSERT(0 != Silo);
+
+    ContextSlot = CALL(PsGetSiloMonitorContextSlot)(FspSiloMonitor);
+
+    /* if we cannot get the Globals, it must mean that we failed in Create callback */
+    Result = CALL(PsGetSiloContext)(Silo, ContextSlot, &Globals);
+    if (!NT_SUCCESS(Result))
+        return;
+    CALL(PsDereferenceSiloContext)(Globals);
+    Globals = 0;
+
+    if (0 != FspSiloFiniCallback)
+    {
+        FSP_PESILO PreviousSilo = CALL(PsAttachSiloToCurrentThread)(Silo);
+        FspSiloFiniCallback();
+        CALL(PsDetachSiloFromCurrentThread)(PreviousSilo);
+    }
+
+    /* PsRemoveSiloContext removes reference to Globals (possibly freeing it) */
+    CALL(PsRemoveSiloContext)(Silo, ContextSlot, 0);
+}
+
+NTSTATUS FspSiloInitialize(FSP_SILO_INIT_CALLBACK Init, FSP_SILO_FINI_CALLBACK Fini)
+{
+    NTSTATUS Result = STATUS_SUCCESS;
+
+    if (FspIsNtDdiVersionAvailable(NTDDI_WIN10_RS5))
+    {
+        ULONG Fail = 0;
+
+        LOAD(PsRegisterSiloMonitor);
+        LOAD(PsStartSiloMonitor);
+        LOAD(PsUnregisterSiloMonitor);
+        LOAD(PsGetSiloMonitorContextSlot);
+        LOAD(PsCreateSiloContext);
+        LOAD(PsDereferenceSiloContext);
+        LOAD(PsInsertSiloContext);
+        LOAD(PsRemoveSiloContext);
+        LOAD(PsGetSiloContext);
+        LOAD(PsAttachSiloToCurrentThread);
+        LOAD(PsDetachSiloFromCurrentThread);
+        LOAD(PsGetCurrentServerSilo);
+        LOAD(PsGetSiloContainerId);
+
+        if (0 == Fail)
+        {
+            FSP_SILO_MONITOR_REGISTRATION Registration =
+            {
+                .Version = FSP_SILO_MONITOR_REGISTRATION_VERSION,
+                .MonitorHost = FALSE,
+                .MonitorExistingSilos = TRUE,
+                .DriverObjectName = 0,
+                .CreateCallback = FspSiloMonitorCreateCallback,
+                .TerminateCallback = FspSiloMonitorTerminateCallback,
+            };
+            FSP_PSILO_MONITOR Monitor = 0;
+            UNICODE_STRING DriverName;
+
+            RtlInitUnicodeString(&DriverName, L"" DRIVER_NAME);
+            Registration.DriverObjectName = &DriverName;
+            Result = CALL(PsRegisterSiloMonitor)(&Registration, &Monitor);
+            if (!NT_SUCCESS(Result))
+                goto exit;
+
+            Result = CALL(PsStartSiloMonitor)(Monitor);
+            if (!NT_SUCCESS(Result))
+                goto exit;
+
+            FspSiloMonitor = Monitor;
+            FspSiloInitCallback = Init;
+            FspSiloFiniCallback = Fini;
+
+            FspSiloInitDone = TRUE;
+            Result = STATUS_SUCCESS;
+
+        exit:
+            if (!NT_SUCCESS(Result))
+            {
+                if (0 != Monitor)
+                    CALL(PsUnregisterSiloMonitor)(Monitor);
+            }
+        }
+    }
+
+    return Result;
+}
+
+VOID FspSiloFinalize(VOID)
+{
+    if (!FspSiloInitDone)
+        return;
+
+    CALL(PsUnregisterSiloMonitor)(FspSiloMonitor);
+}

src/sys/util.c

@@ -21,6 +21,7 @@
 
 #include <sys/driver.h>
 
+BOOLEAN FspIsNtDdiVersionAvailable(ULONG Version);
 NTSTATUS FspCreateGuid(GUID *Guid);
 NTSTATUS FspGetDeviceObjectPointer(PUNICODE_STRING ObjectName, ACCESS_MASK DesiredAccess,
     PULONG PFileNameIndex, PFILE_OBJECT *PFileObject, PDEVICE_OBJECT *PDeviceObject);
@@ -132,6 +133,7 @@ PVOID FspIrpHookContext(PVOID Context);
 NTSTATUS FspIrpHookNext(PDEVICE_OBJECT DeviceObject, PIRP Irp, PVOID Context);
 
 #ifdef ALLOC_PRAGMA
+#pragma alloc_text(PAGE, FspIsNtDdiVersionAvailable)
 #pragma alloc_text(PAGE, FspCreateGuid)
 #pragma alloc_text(PAGE, FspGetDeviceObjectPointer)
 #pragma alloc_text(PAGE, FspRegistryGetValue)
@@ -223,6 +225,75 @@ PVOID FspAllocateIrpMustSucceed(CCHAR StackSize)
     }
 }
 
+BOOLEAN FspIsNtDdiVersionAvailable(ULONG RequestedVersion)
+{
+    PAGED_CODE();
+
+    static ULONG Version;
+
+    if (0 == Version)
+    {
+        RTL_OSVERSIONINFOEXW VersionInfo;
+        ULONG TempVersion;
+
+        RtlZeroMemory(&VersionInfo, sizeof VersionInfo);
+        VersionInfo.dwOSVersionInfoSize = sizeof VersionInfo;
+        RtlGetVersion((PVOID)&VersionInfo);
+
+        TempVersion =
+            ((UINT8)VersionInfo.dwMajorVersion << 24) |
+            ((UINT8)VersionInfo.dwMinorVersion << 16) |
+            ((UINT8)VersionInfo.wServicePackMajor << 8);
+
+        if (10 <= VersionInfo.dwMajorVersion)
+        {
+            /* see https://docs.microsoft.com/en-us/windows/release-information/ */
+            static struct
+            {
+                ULONG BuildNumber;
+                ULONG Subver;
+            } Builds[] =
+            {
+                { 10240, SUBVER(NTDDI_WIN10) },
+                { 10586, SUBVER(NTDDI_WIN10_TH2) },
+                { 14393, SUBVER(NTDDI_WIN10_RS1) },
+                { 15063, SUBVER(NTDDI_WIN10_RS2) },
+                { 16299, SUBVER(NTDDI_WIN10_RS3) },
+                { 17134, SUBVER(NTDDI_WIN10_RS4) },
+                { 17763, SUBVER(NTDDI_WIN10_RS5) },
+                { 18362, SUBVER(NTDDI_WIN10_19H1) },
+                { 18363, SUBVER(NTDDI_WIN10_19H1) },
+                { 19041, 9 },
+                { (ULONG)-1, 10 },
+            };
+            int Lo = 0, Hi = sizeof Builds / sizeof Builds[0] - 1, Mi;
+
+            while (Lo <= Hi)
+            {
+                Mi = (unsigned)(Lo + Hi) >> 1;
+
+                if (Builds[Mi].BuildNumber < VersionInfo.dwBuildNumber)
+                    Lo = Mi + 1;
+                else if (Builds[Mi].BuildNumber > VersionInfo.dwBuildNumber)
+                    Hi = Mi - 1;
+                else
+                {
+                    Lo = Mi;
+                    break;
+                }
+            }
+            Mi = Lo;
+
+            TempVersion |= (UINT8)Builds[Mi].Subver;
+        }
+
+        /* thread-safe because multiple threads will compute same value */
+        InterlockedExchange((PVOID)&Version, TempVersion);
+    }
+
+    return RequestedVersion <= Version;
+}
+
 NTSTATUS FspCreateGuid(GUID *Guid)
 {
     PAGED_CODE();

src/sys/volume.c

@@ -24,11 +24,13 @@
 NTSTATUS FspVolumeCreate(
     PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp);
 static NTSTATUS FspVolumeCreateNoLock(
-    PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp);
+    PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp,
+    FSP_SILO_GLOBALS *Globals);
 VOID FspVolumeDelete(
     PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp);
 static VOID FspVolumeDeleteNoLock(
-    PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp);
+    PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp,
+    FSP_SILO_GLOBALS *Globals);
 static WORKER_THREAD_ROUTINE FspVolumeDeleteDelayed;
 NTSTATUS FspVolumeMount(
     PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp);
@@ -77,15 +79,25 @@ NTSTATUS FspVolumeCreate(
 {
     PAGED_CODE();
 
+    FSP_SILO_GLOBALS *Globals;
     NTSTATUS Result;
+
+    FspSiloGetGlobals(&Globals);
+    ASSERT(0 != Globals);
+
     FspDeviceGlobalLock();
-    Result = FspVolumeCreateNoLock(FsctlDeviceObject, Irp, IrpSp);
+    Result = FspVolumeCreateNoLock(FsctlDeviceObject, Irp, IrpSp,
+        Globals);
     FspDeviceGlobalUnlock();
+
+    FspSiloDereferenceGlobals(Globals);
+
     return Result;
 }
 
 static NTSTATUS FspVolumeCreateNoLock(
-    PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp)
+    PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp,
+    FSP_SILO_GLOBALS *Globals)
 {
     PAGED_CODE();
 
@@ -302,18 +314,18 @@ static NTSTATUS FspVolumeCreateNoLock(
     /* do we need to register with fsmup? */
     if (0 == FsvrtDeviceObject)
     {
-        Result = FspMupRegister(FspFsmupDeviceObject, FsvolDeviceObject);
+        Result = FspMupRegister(Globals->FsmupDeviceObject, FsvolDeviceObject);
         if (!NT_SUCCESS(Result))
         {
             FspDeviceDereference(FsvolDeviceObject);
             return Result;
         }
 
-        RtlInitUnicodeString(&FsmupDeviceName, L"\\Device\\" FSP_FSCTL_MUP_DEVICE_NAME);
+        RtlInitUnicodeString(&FsmupDeviceName, Globals->FsmupDeviceNameBuf);
         Result = IoCreateSymbolicLink(&FsvolDeviceExtension->VolumeName, &FsmupDeviceName);
         if (!NT_SUCCESS(Result))
         {
-            FspMupUnregister(FspFsmupDeviceObject, FsvolDeviceObject);
+            FspMupUnregister(Globals->FsmupDeviceObject, FsvolDeviceObject);
             FspDeviceDereference(FsvolDeviceObject);
             return Result;
         }
@@ -331,6 +343,7 @@ VOID FspVolumeDelete(
 {
     // !PAGED_CODE();
 
+    FSP_SILO_GLOBALS *Globals;
     PDEVICE_OBJECT FsvolDeviceObject = IrpSp->FileObject->FsContext2;
     FSP_FSVOL_DEVICE_EXTENSION *FsvolDeviceExtension = FspFsvolDeviceExtension(FsvolDeviceObject);
     PDEVICE_OBJECT FsvrtDeviceObject = FsvolDeviceExtension->FsvrtDeviceObject;
@@ -350,10 +363,16 @@ VOID FspVolumeDelete(
 
     FspDeviceReference(FsvolDeviceObject);
 
+    FspSiloGetGlobals(&Globals);
+    ASSERT(0 != Globals);
+
     FspDeviceGlobalLock();
-    FspVolumeDeleteNoLock(FsctlDeviceObject, Irp, IrpSp);
+    FspVolumeDeleteNoLock(FsctlDeviceObject, Irp, IrpSp,
+        Globals);
     FspDeviceGlobalUnlock();
 
+    FspSiloDereferenceGlobals(Globals);
+
     /*
      * Call MmForceSectionClosed on active files to ensure that Mm removes them from Standby List.
      */
@@ -370,7 +389,8 @@ VOID FspVolumeDelete(
 }
 
 static VOID FspVolumeDeleteNoLock(
-    PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp)
+    PDEVICE_OBJECT FsctlDeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp,
+    FSP_SILO_GLOBALS *Globals)
 {
     // !PAGED_CODE();
 
@@ -445,7 +465,7 @@ static VOID FspVolumeDeleteNoLock(
     else
     {
         IoDeleteSymbolicLink(&FsvolDeviceExtension->VolumeName);
-        FspMupUnregister(FspFsmupDeviceObject, FsvolDeviceObject);
+        FspMupUnregister(Globals->FsmupDeviceObject, FsvolDeviceObject);
     }
 
     /* release the volume device object */
@@ -945,6 +965,7 @@ NTSTATUS FspVolumeTransact(
                 if (0 != InternalBuffer)
                 {
                     ASSERT(FSP_FSCTL_TRANSACT_INTERNAL == ControlCode);
+                    *(PVOID *)OutputBuffer = 0;
                     FspFree(InternalBuffer);
                 }
                 FspIopCompleteCanceledIrp(PendingIrp);

tools/build-choco.bat

@@ -19,7 +19,7 @@ if X%~nx0==Xbuild-choco.bat (
     goto :choco
 )
 
-call "%VS140COMNTOOLS%\..\..\VC\vcvarsall.bat" x64
+call "%~dp0vcvarsall.bat" x64
 
 if not X%SignedPackage%==X (
     if not exist "%~dp0..\build\VStudio\build\%Configuration%\winfsp-*.msi" (echo previous build not found >&2 & exit /b 1)

tools/build-sample.bat

@@ -10,7 +10,7 @@ if not X%4==X set ProjDir=%~4
 
 if X!ProjDir!==X (echo usage: build-sample Config Arch Sample ProjDir >&2 & goto fail)
 
-call "%VS140COMNTOOLS%\..\..\VC\vcvarsall.bat" x64
+call "%~dp0vcvarsall.bat" x64
 
 if X!FSP_SAMPLE_DIR!==X (
 	set RegKey="HKLM\SOFTWARE\WinFsp"

tools/build.bat

@@ -19,7 +19,7 @@ if X%~nx0==Xbuild-choco.bat (
     goto :choco
 )
 
-call "%VS140COMNTOOLS%\..\..\VC\vcvarsall.bat" x64
+call "%~dp0vcvarsall.bat" x64
 
 if not X%SignedPackage%==X (
     if not exist "%~dp0..\build\VStudio\build\%Configuration%\winfsp-*.msi" (echo previous build not found >&2 & exit /b 1)

tools/debug.bat

@@ -12,4 +12,4 @@ reg query %RegKey% /v %RegVal% >nul 2>&1 || (echo Cannot find Windows Kit >&2 &
 for /f "tokens=2,*" %%i in ('reg query %RegKey% /v %RegVal% ^| findstr %RegVal%') do (
     set KitRoot="%%j"
 )
-start "winfsp" %KitRoot%\Debuggers\x64\windbg -W %DebugWorkspace% -k net:port=%DebugPort%,key=%DebugKey%
+start "%DebugWorkspace%" %KitRoot%\Debuggers\x64\windbg -W %DebugWorkspace% -k net:port=%DebugPort%,key=%DebugKey%

tools/deploy.bat

@@ -1,21 +1,36 @@
 @echo off
 
 setlocal
+setlocal EnableDelayedExpansion
 
-set CONFIG=Debug
-set SUFFIX=x64
-set TARGET_MACHINE=WIN8DBG
-if not X%1==X set TARGET_MACHINE=%1
-set TARGET_ACCOUNT=\Users\%USERNAME%\Downloads\winfsp\
-set TARGET=\\%TARGET_MACHINE%%TARGET_ACCOUNT%
+set Config=Debug
+set Suffix=x64
+set Deploy=C:\Deploy\winfsp
+set Target=Win10DBG
+set Chkpnt=winfsp
+if not X%1==X set Target=%1
+if not X%2==X set Chkpnt=%2
 
-cd %~dp0..
-mkdir %TARGET% 2>nul
-for %%f in (winfsp-%SUFFIX%.sys winfsp-%SUFFIX%.dll winfsp-tests-%SUFFIX%.exe fsbench-%SUFFIX%.exe fscrash-%SUFFIX%.exe memfs-%SUFFIX%.exe) do (
-	copy build\VStudio\build\%CONFIG%\%%f %TARGET% >nul
+(
+    echo regsvr32 /s winfsp-x64.dll
+) > %~dp0..\build\VStudio\build\%Config%\deploy-setup.bat
+
+set Files=
+for %%f in (
+    %~dp0..\build\VStudio\build\%Config%\
+        winfsp-%Suffix%.sys
+        winfsp-%Suffix%.dll
+        winfsp-tests-%Suffix%.exe
+        memfs-%Suffix%.exe
+        deploy-setup.bat
+    ) do (
+    set File=%%~f
+    if [!File:~-1!] == [\] (
+        set Dir=!File!
+    ) else (
+        if not [!Files!] == [] set Files=!Files!,
+        set Files=!Files!'!Dir!!File!'
+    )
 )
-copy tools\ifstest.bat %TARGET% >nul
-echo sc create WinFsp type=filesys binPath=%%~dp0winfsp-%SUFFIX%.sys >%TARGET%sc-create.bat
-echo sc start WinFsp >%TARGET%sc-start.bat
-echo sc stop WinFsp >%TARGET%sc-stop.bat
-echo sc delete WinFsp >%TARGET%sc-delete.bat
+
+powershell -NoProfile -ExecutionPolicy Bypass -Command "& '%~dp0deploy.ps1' -Name '%Target%' -CheckpointName '%Chkpnt%' -Files !Files! -Destination '%Deploy%'"

tools/deploy.ps1

@@ -0,0 +1,35 @@
+param (
+    [Parameter(Mandatory)][string]$Name,
+    [string]$CheckpointName,
+    [Parameter(Mandatory)][string[]]$Files,
+    [Parameter(Mandatory)][string]$Destination
+)
+
+function Restore-VM ($Name, $CheckpointName) {
+    $VM = Get-VM -Name $Name
+    if ($VM.State -eq "Running") {
+        Stop-VM -Name $Name -TurnOff
+    }
+
+    if (-not $CheckpointName) {
+        $Checkpoint = Get-VMCheckpoint -VMName $Name |
+            Sort-Object -Property CreationTime -Descending |
+            select -First 1
+    } else {
+        $Checkpoint = Get-VMCheckpoint -VMName $Name -Name $CheckpointName
+    }
+    Restore-VMCheckpoint -VMCheckpoint $Checkpoint -Confirm:$false
+
+    Start-VM -Name $Name
+}
+
+function Deploy-VMFiles ($Name, $Files, $Destination) {
+    foreach ($File in $Files) {
+        $Leaf = Split-Path -Path $File -Leaf
+        $Dest = Join-Path $Destination $Leaf
+        Copy-VMFile -Name $Name -SourcePath $File -DestinationPath $Dest -FileSource Host -CreateFullPath -Force
+    }
+}
+
+Restore-VM -Name $Name -CheckpointName $CheckpointName
+Deploy-VMFiles -Name $Name -Files $Files -Destination $Destination

tools/impdef.bat

@@ -19,7 +19,7 @@ set cdef=/D_AMD64_
 if /i X%outarch%==Xx86 set arch=x86
 if /i X%outarch%==Xx86 set cdef=/D_X86_
 
-call "%VS140COMNTOOLS%\..\..\VC\vcvarsall.bat" !arch!
+call "%~dp0vcvarsall.bat" !arch!
 set INCLUDE=%~dp0..\opt\fsext\inc;%~dp0..\inc;!WindowsSdkDir!Include\!WindowsSDKVersion!km\crt;!WindowsSdkDir!Include\!WindowsSDKVersion!km;!WindowsSdkDir!Include\!WindowsSDKVersion!km\shared;!INCLUDE!
 
 if exist !workdir! rmdir /s/q !workdir!

tools/nmake-ext-test.bat

@@ -5,7 +5,7 @@ setlocal
 set Configuration=Release
 if not X%1==X set Configuration=%1
 
-call "%VS140COMNTOOLS%\..\..\VC\vcvarsall.bat" x64
+call "%~dp0vcvarsall.bat" x64
 
 cd %~dp0..\ext\test
 nmake /f Nmakefile

tools/ntstatus.bat

@@ -11,4 +11,9 @@ for /f "tokens=2,*" %%i in ('reg query %RegKey% /v %RegVal% ^| findstr %RegVal%'
     set KitRoot=%%j
 )
 
-findstr /R /I "\<0*[Xx]*%1[Ll]*\>" "%KitRoot%Include\10.0.10586.0\shared\%~n0.h"
+set KitVer=10.0.10586.0
+for /f "tokens=*" %%i in ('dir /ad/b "%KitRoot%Include\10.*"') do (
+    set KitVer=%%i
+)
+
+findstr /R /I "\<0*[Xx]*%1[Ll]*\>" "%KitRoot%Include\%KitVer%\shared\%~n0.h"

tools/vcvarsall.bat

@@ -0,0 +1,10 @@
+@echo off
+
+set vcvarsall="%VS140COMNTOOLS%\..\..\VC\vcvarsall.bat"
+set vswhere="%ProgramFiles(x86)%\Microsoft Visual Studio\Installer\vswhere.exe"
+if exist %vswhere% (
+    for /f "usebackq tokens=*" %%i in (`%vswhere% -find VC\**\vcvarsall.bat`) do (
+        set vcvarsall="%%i"
+    )
+)
+call %vcvarsall% %*

tools/winerror.bat

@@ -11,4 +11,9 @@ for /f "tokens=2,*" %%i in ('reg query %RegKey% /v %RegVal% ^| findstr %RegVal%'
     set KitRoot=%%j
 )
 
-findstr /R /I "\<0*[Xx]*%1[Ll]*\>" "%KitRoot%Include\10.0.10586.0\shared\%~n0.h"
+set KitVer=10.0.10586.0
+for /f "tokens=*" %%i in ('dir /ad/b "%KitRoot%Include\10.*"') do (
+    set KitVer=%%i
+)
+
+findstr /R /I "\<0*[Xx]*%1[Ll]*\>" "%KitRoot%Include\%KitVer%\shared\%~n0.h"

tst/winfsp-tests/info-test.c

@@ -1930,6 +1930,44 @@ void setvolinfo_test(void)
     }
 }
 
+void query_winfsp_dotest(ULONG Flags, PWSTR Prefix, ULONG FileInfoTimeout, BOOLEAN ExpectWinFsp)
+{
+    void* memfs = memfs_start_ex(Flags, FileInfoTimeout);
+
+    WCHAR FilePath[MAX_PATH];
+    HANDLE Handle;
+    DWORD BytesTransferred;
+
+    StringCbPrintfW(FilePath, sizeof FilePath, L"%s%s\\",
+        Prefix ? L"" : L"\\\\?\\GLOBALROOT", Prefix ? Prefix : memfs_volumename(memfs));
+
+    Handle = CreateFileW(FilePath,
+        0, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS, 0);
+    ASSERT(INVALID_HANDLE_VALUE != Handle);
+
+    if (ExpectWinFsp)
+        ASSERT(DeviceIoControl(Handle, FSP_FSCTL_QUERY_WINFSP, 0, 0, 0, 0, &BytesTransferred, 0));
+    else
+        ASSERT(!DeviceIoControl(Handle, FSP_FSCTL_QUERY_WINFSP, 0, 0, 0, 0, &BytesTransferred, 0) &&
+            ERROR_INVALID_FUNCTION == GetLastError());
+
+    CloseHandle(Handle);
+
+    memfs_stop(memfs);
+}
+
+void query_winfsp_test(void)
+{
+    if (NtfsTests)
+        return;
+
+    if (WinFspDiskTests)
+        query_winfsp_dotest(MemfsDisk, 0, 0, TRUE);
+    if (WinFspNetTests)
+        query_winfsp_dotest(MemfsNet, L"\\\\memfs\\share", 0, TRUE);
+}
+
 void info_tests(void)
 {
     if (!OptShareName)
@@ -1955,4 +1993,6 @@ void info_tests(void)
         TEST(rename_pid_test);
     TEST(getvolinfo_test);
     TEST(setvolinfo_test);
+    if (!NtfsTests)
+        TEST(query_winfsp_test);
 }