sys: ioq

build/VStudio/winfsp.vcxproj

@@ -142,6 +142,7 @@
     <ClCompile Include="..\..\src\sys\fileinfo.c" />
     <ClCompile Include="..\..\src\sys\flush.c" />
     <ClCompile Include="..\..\src\sys\fsctl.c" />
+    <ClCompile Include="..\..\src\sys\ioq.c" />
     <ClCompile Include="..\..\src\sys\lockctl.c" />
     <ClCompile Include="..\..\src\sys\misc.c" />
     <ClCompile Include="..\..\src\sys\read.c" />

build/VStudio/winfsp.vcxproj.filters

@@ -74,6 +74,9 @@
     <ClCompile Include="..\..\src\sys\misc.c">
       <Filter>Source</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\sys\ioq.c">
+      <Filter>Source</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\src\sys\driver.h">

src/sys/driver.h

@@ -113,51 +113,6 @@
 #pragma warning(disable:4100)           /* unreferenced formal parameter */
 #pragma warning(disable:4200)           /* zero-sized array in struct/union */
 
-/* types */
-enum
-{
-    FspFsctlDeviceExtensionKind = 'C',  /* file system control device (e.g. \Device\WinFsp.Disk) */
-    FspFsvrtDeviceExtensionKind = 'V',  /* virtual volume device (e.g. \Device\Volume{GUID}) */
-    FspFsvolDeviceExtensionKind = 'F',  /* file system volume device (unnamed) */
-};
-typedef struct
-{
-    UINT8 Kind;
-} FSP_DEVICE_EXTENSION;
-typedef struct
-{
-    FSP_DEVICE_EXTENSION Base;
-} FSP_FSCTL_DEVICE_EXTENSION;
-typedef struct
-{
-    FSP_DEVICE_EXTENSION Base;
-    UINT8 SecurityDescriptorBuf[];
-} FSP_FSVRT_DEVICE_EXTENSION;
-typedef struct
-{
-    FSP_DEVICE_EXTENSION Base;
-} FSP_FSVOL_DEVICE_EXTENSION;
-static inline
-FSP_DEVICE_EXTENSION *FspDeviceExtension(PDEVICE_OBJECT DeviceObject)
-{
-    return DeviceObject->DeviceExtension;
-}
-static inline
-FSP_FSCTL_DEVICE_EXTENSION *FspFsctlDeviceExtension(PDEVICE_OBJECT DeviceObject)
-{
-    return DeviceObject->DeviceExtension;
-}
-static inline
-FSP_FSVRT_DEVICE_EXTENSION *FspFsvrtDeviceExtension(PDEVICE_OBJECT DeviceObject)
-{
-    return DeviceObject->DeviceExtension;
-}
-static inline
-FSP_FSVOL_DEVICE_EXTENSION *FspFsvolDeviceExtension(PDEVICE_OBJECT DeviceObject)
-{
-    return DeviceObject->DeviceExtension;
-}
-
 /* driver major functions */
 DRIVER_DISPATCH FspCleanup;
 DRIVER_DISPATCH FspClose;
@@ -190,6 +145,68 @@ FAST_IO_RELEASE_FOR_MOD_WRITE FspReleaseForModWrite;
 FAST_IO_ACQUIRE_FOR_CCFLUSH FspAcquireForCcFlush;
 FAST_IO_RELEASE_FOR_CCFLUSH FspReleaseForCcFlush;
 
+/* I/O queue */
+typedef struct
+{
+    KSPIN_LOCK SpinLock;
+    int Enabled;
+    LIST_ENTRY PendingIrpList, ProcessIrpList;
+    IO_CSQ PendingIoCsq, ProcessIoCsq;
+} FSP_IOQ;
+VOID FspIoqInitialize(FSP_IOQ *Ioq);
+VOID FspIoqEnable(FSP_IOQ *Ioq, int Delta);
+BOOLEAN FspIoqPostIrp(FSP_IOQ *Ioq, PIRP Irp);
+PIRP FspIoqNextPendingIrp(FSP_IOQ *Ioq);
+BOOLEAN FspIoqProcessIrp(FSP_IOQ *Ioq, PIRP Irp);
+PIRP FspIoqRemoveProcessIrp(FSP_IOQ *Ioq, UINT_PTR IrpHint);
+VOID FspIoqCancelAll(FSP_IOQ *Ioq);
+
+/* device extensions */
+enum
+{
+    FspFsctlDeviceExtensionKind = 'C',  /* file system control device (e.g. \Device\WinFsp.Disk) */
+    FspFsvrtDeviceExtensionKind = 'V',  /* virtual volume device (e.g. \Device\Volume{GUID}) */
+    FspFsvolDeviceExtensionKind = 'F',  /* file system volume device (unnamed) */
+};
+typedef struct
+{
+    UINT8 Kind;
+} FSP_DEVICE_EXTENSION;
+typedef struct
+{
+    FSP_DEVICE_EXTENSION Base;
+} FSP_FSCTL_DEVICE_EXTENSION;
+typedef struct
+{
+    FSP_DEVICE_EXTENSION Base;
+    FSP_IOQ Ioq;
+    UINT8 SecurityDescriptorBuf[];
+} FSP_FSVRT_DEVICE_EXTENSION;
+typedef struct
+{
+    FSP_DEVICE_EXTENSION Base;
+} FSP_FSVOL_DEVICE_EXTENSION;
+static inline
+FSP_DEVICE_EXTENSION *FspDeviceExtension(PDEVICE_OBJECT DeviceObject)
+{
+    return DeviceObject->DeviceExtension;
+}
+static inline
+FSP_FSCTL_DEVICE_EXTENSION *FspFsctlDeviceExtension(PDEVICE_OBJECT DeviceObject)
+{
+    return DeviceObject->DeviceExtension;
+}
+static inline
+FSP_FSVRT_DEVICE_EXTENSION *FspFsvrtDeviceExtension(PDEVICE_OBJECT DeviceObject)
+{
+    return DeviceObject->DeviceExtension;
+}
+static inline
+FSP_FSVOL_DEVICE_EXTENSION *FspFsvolDeviceExtension(PDEVICE_OBJECT DeviceObject)
+{
+    return DeviceObject->DeviceExtension;
+}
+
 /* misc */
 NTSTATUS CreateGuid(GUID *Guid);
 NTSTATUS SecuritySubjectContextAccessCheck(

src/sys/ioq.c

@@ -0,0 +1,209 @@
+/**
+ * @file sys/ioq.c
+ *
+ * @copyright 2015 Bill Zissimopoulos
+ */
+
+#include <sys/driver.h>
+
+/*
+ * An FSP_IOQ encapsulates the main FSP mechanism for handling IRP's.
+ * It has two queues: a "pending" queue for managing newly arrived IRP's
+ * and a "processing" queue for managing IRP's currently being processed
+ * (i.e. sent to the user-mode file system for further processing).
+ *
+ * IRP's arrive at a MajorFunction (MJ) and are then posted to the device's
+ * FSP_IOQ and marked pending. When the user-mode file system performs
+ * FSP_FSCTL_TRANSACT, the IRP's are removed from the pending queue and
+ * are then marshalled to the user process; prior to that they are added
+ * to the processing queue. At a later time the user-mode will perform
+ * another FSP_FSCTL_TRANSACT at which time any processed IRP's will be
+ * marshalled back to us and will be then removed from the processing queue
+ * and completed.
+ *
+ * State diagram:
+ *                                 +--------------------+
+ *           |                     |                    | ProcessIrp
+ *           v                     |                    v
+ *     +------------+              |              +------------+
+ *     |     MJ     |              |              | Processing |
+ *     +------------+              |              +------------+
+ *           |                     |                    |
+ *           | PostIrp             |                    | RemoveProcessIrp
+ *           v                     |                    v
+ *     +------------+              |              +------------+
+ *     |   Pending  |              |              |  TRANSACT  |
+ *     +------------+              |              |     IN     |
+ *           |                     |              +------------+
+ *           | NextPendingIrp      |                    |
+ *           v                     |                    | CompleteIrp
+ *     +------------+              |                    v
+ *     |  TRANSACT  |              |              +------------+
+ *     |    OUT     |              |              | Completed  |
+ *     +------------+              |              +------------+
+ *           |                     |
+ *           +---------------------+
+ */
+
+static NTSTATUS FspIoqPendingInsertIrpEx(PIO_CSQ IoCsq, PIRP Irp, PVOID InsertContext)
+{
+    FSP_IOQ *Ioq = CONTAINING_RECORD(IoCsq, FSP_IOQ, PendingIoCsq);
+
+    if (0 > Ioq->Enabled)
+        return STATUS_ACCESS_DENIED;
+
+    InsertTailList(&Ioq->PendingIrpList, &Irp->Tail.Overlay.ListEntry);
+    return STATUS_SUCCESS;
+}
+
+static VOID FspIoqPendingRemoveIrp(PIO_CSQ IoCsq, PIRP Irp)
+{
+    RemoveEntryList(&Irp->Tail.Overlay.ListEntry);
+}
+
+static PIRP FspIoqPendingPeekNextIrp(PIO_CSQ IoCsq, PIRP Irp, PVOID PeekContext)
+{
+    FSP_IOQ *Ioq = CONTAINING_RECORD(IoCsq, FSP_IOQ, PendingIoCsq);
+    PLIST_ENTRY Head, Entry;
+
+    if (!PeekContext && 0 > Ioq->Enabled)
+        return 0;
+
+    Head = &Ioq->PendingIrpList;
+    if (0 == Irp)
+        Entry = Head->Flink;
+    else
+        Entry = Irp->Tail.Overlay.ListEntry.Flink;
+
+    return Head != Entry ? CONTAINING_RECORD(Entry, IRP, Tail.Overlay.ListEntry) : 0;
+}
+
+static VOID FspIoqPendingAcquireLock(PIO_CSQ IoCsq, PKIRQL Irql)
+{
+    FSP_IOQ *Ioq = CONTAINING_RECORD(IoCsq, FSP_IOQ, PendingIoCsq);
+    KeAcquireSpinLock(&Ioq->SpinLock, Irql);
+}
+
+static VOID FspIoqPendingReleaseLock(PIO_CSQ IoCsq, KIRQL Irql)
+{
+    FSP_IOQ *Ioq = CONTAINING_RECORD(IoCsq, FSP_IOQ, PendingIoCsq);
+    KeReleaseSpinLock(&Ioq->SpinLock, Irql);
+}
+
+static NTSTATUS FspIoqProcessInsertIrpEx(PIO_CSQ IoCsq, PIRP Irp, PVOID InsertContext)
+{
+    FSP_IOQ *Ioq = CONTAINING_RECORD(IoCsq, FSP_IOQ, ProcessIoCsq);
+
+    if (0 > Ioq->Enabled)
+        return STATUS_ACCESS_DENIED;
+
+    InsertTailList(&Ioq->ProcessIrpList, &Irp->Tail.Overlay.ListEntry);
+    return STATUS_SUCCESS;
+}
+
+static VOID FspIoqProcessRemoveIrp(PIO_CSQ IoCsq, PIRP Irp)
+{
+    RemoveEntryList(&Irp->Tail.Overlay.ListEntry);
+}
+
+static PIRP FspIoqProcessPeekNextIrp(PIO_CSQ IoCsq, PIRP Irp, PVOID PeekContext)
+{
+    FSP_IOQ *Ioq = CONTAINING_RECORD(IoCsq, FSP_IOQ, ProcessIoCsq);
+    PLIST_ENTRY Head, Entry;
+
+    if (!PeekContext && 0 > Ioq->Enabled)
+        return 0;
+
+    Head = &Ioq->ProcessIrpList;
+    if (0 == Irp)
+        Entry = Head->Flink;
+    else
+        Entry = Irp->Tail.Overlay.ListEntry.Flink;
+
+    for (; Head != Entry; Entry = Entry->Flink)
+    {
+        Irp = CONTAINING_RECORD(Entry, IRP, Tail.Overlay.ListEntry);
+        if (Irp == PeekContext)
+            return Irp;
+    }
+
+    return 0;
+}
+
+static VOID FspIoqProcessAcquireLock(PIO_CSQ IoCsq, PKIRQL Irql)
+{
+    FSP_IOQ *Ioq = CONTAINING_RECORD(IoCsq, FSP_IOQ, ProcessIoCsq);
+    KeAcquireSpinLock(&Ioq->SpinLock, Irql);
+}
+
+static VOID FspIoqProcessReleaseLock(PIO_CSQ IoCsq, KIRQL Irql)
+{
+    FSP_IOQ *Ioq = CONTAINING_RECORD(IoCsq, FSP_IOQ, ProcessIoCsq);
+    KeReleaseSpinLock(&Ioq->SpinLock, Irql);
+}
+
+static VOID FspIoqCompleteCanceledIrp(PIO_CSQ IoCsq, PIRP Irp)
+{
+    Irp->IoStatus.Status = STATUS_CANCELLED;
+    Irp->IoStatus.Information = 0;
+    IoCompleteRequest(Irp, FSP_IO_INCREMENT);
+}
+
+VOID FspIoqInitialize(FSP_IOQ *Ioq)
+{
+    RtlZeroMemory(Ioq, sizeof *Ioq);
+    KeInitializeSpinLock(&Ioq->SpinLock);
+    InitializeListHead(&Ioq->PendingIrpList);
+    InitializeListHead(&Ioq->ProcessIrpList);
+    IoCsqInitializeEx(&Ioq->PendingIoCsq,
+        FspIoqPendingInsertIrpEx,
+        FspIoqPendingRemoveIrp,
+        FspIoqPendingPeekNextIrp,
+        FspIoqPendingAcquireLock,
+        FspIoqPendingReleaseLock,
+        FspIoqCompleteCanceledIrp);
+    IoCsqInitializeEx(&Ioq->ProcessIoCsq,
+        FspIoqProcessInsertIrpEx,
+        FspIoqProcessRemoveIrp,
+        FspIoqProcessPeekNextIrp,
+        FspIoqProcessAcquireLock,
+        FspIoqProcessReleaseLock,
+        FspIoqCompleteCanceledIrp);
+}
+
+VOID FspIoqEnable(FSP_IOQ *Ioq, int Delta)
+{
+    KIRQL Irql;
+    KeAcquireSpinLock(&Ioq->SpinLock, &Irql);
+    Ioq->Enabled += Delta;
+    KeReleaseSpinLock(&Ioq->SpinLock, Irql);
+}
+
+BOOLEAN FspIoqPostIrp(FSP_IOQ *Ioq, PIRP Irp)
+{
+    return STATUS_SUCCESS == IoCsqInsertIrpEx(&Ioq->PendingIoCsq, Irp, 0, 0);
+}
+
+PIRP FspIoqNextPendingIrp(FSP_IOQ *Ioq)
+{
+    return IoCsqRemoveNextIrp(&Ioq->PendingIoCsq, (PVOID)1);
+}
+
+BOOLEAN FspIoqProcessIrp(FSP_IOQ *Ioq, PIRP Irp)
+{
+    return STATUS_SUCCESS == IoCsqInsertIrpEx(&Ioq->ProcessIoCsq, Irp, 0, 0);
+}
+
+PIRP FspIoqRemoveProcessIrp(FSP_IOQ *Ioq, UINT_PTR IrpHint)
+{
+    return IoCsqRemoveNextIrp(&Ioq->PendingIoCsq, (PVOID)IrpHint);
+}
+
+VOID FspIoqCancelAll(FSP_IOQ *Ioq)
+{
+    PIRP Irp;
+    while (0 != (Irp = IoCsqRemoveNextIrp(&Ioq->PendingIoCsq, 0)))
+        FspIoqCompleteCanceledIrp(&Ioq->PendingIoCsq, Irp);
+    while (0 != (Irp = IoCsqRemoveNextIrp(&Ioq->ProcessIoCsq, 0)))
+        FspIoqCompleteCanceledIrp(&Ioq->ProcessIoCsq, Irp);
+}