sys: FsContext now maintains reference to its DeviceObject

src/sys/cleanup.c

@@ -50,56 +50,56 @@ static NTSTATUS FspFsvolCleanup(
 
     NTSTATUS Result;
     FSP_FSVOL_DEVICE_EXTENSION *FsvolDeviceExtension = FspFsvolDeviceExtension(DeviceObject);
-    PDEVICE_OBJECT FsvrtDeviceObject = FsvolDeviceExtension->FsvrtDeviceObject;
+    PFILE_OBJECT FileObject = IrpSp->FileObject;
+    FSP_FILE_CONTEXT *FsContext = FileObject->FsContext;
+    UINT64 UserContext = FsContext->UserContext;
+    UINT64 UserContext2 = (UINT_PTR)FileObject->FsContext2;
+    BOOLEAN DeletePending;
+    LONG OpenCount;
 
+    /* lock the FsContext */
+    ExAcquireResourceExclusiveLite(FsContext->Header.Resource, TRUE);
+
+    /* propagate the FsContext DeleteOnClose to DeletePending */
+    if (FsContext->DeleteOnClose)
+        FsContext->DeletePending = TRUE;
+    DeletePending = FsContext->DeletePending;
+
+    /* all handles on this FileObject are gone; decrement its FsContext->OpenCount */
+    OpenCount = FspFileContextClose(FsContext);
+
+    /* unlock the FsContext */
+    ExReleaseResourceLite(FsContext->Header.Resource);
+
+    /* is the FsContext going away as well? */
+    if (0 == OpenCount)
+    {
+        /*
+            * The following must be done under the file system volume device Resource,
+            * because we are manipulating its GenericTable.
+            */
+        ExAcquireResourceExclusiveLite(&FsvolDeviceExtension->Base.Resource, TRUE);
+        try
+        {
+            /* remove the FsContext from the file system volume device generic table */
+            FspFsvolDeviceDeleteContext(DeviceObject, FsContext->UserContext, 0);
+        }
+        finally
+        {
+            ExReleaseResourceLite(&FsvolDeviceExtension->Base.Resource);
+        }
+    }
+
+    PDEVICE_OBJECT FsvrtDeviceObject = FsvolDeviceExtension->FsvrtDeviceObject;
     if (!FspDeviceRetain(FsvrtDeviceObject))
         return STATUS_CANCELLED;
+
     try
     {
-        FSP_FSVRT_DEVICE_EXTENSION *FsvrtDeviceExtension =
+        FSP_FSVRT_DEVICE_EXTENSION *FsvrtDeviceExtension = FspFsvrtDeviceExtension(FsvrtDeviceObject);
-            FspFsvrtDeviceExtension(FsvrtDeviceObject);
-        PFILE_OBJECT FileObject = IrpSp->FileObject;
-        FSP_FILE_CONTEXT *FsContext = FileObject->FsContext;
-        UINT64 UserContext = FsContext->UserContext;
-        UINT64 UserContext2 = (UINT_PTR)FileObject->FsContext2;
         BOOLEAN FileNameRequired = 0 != FsvrtDeviceExtension->VolumeParams.FileNameRequired;
-        BOOLEAN DeletePending;
-        LONG OpenCount;
         FSP_FSCTL_TRANSACT_REQ *Request;
 
-        /* lock the FsContext */
-        ExAcquireResourceExclusiveLite(FsContext->Header.Resource, TRUE);
-
-        /* propagate the FsContext DeleteOnClose to DeletePending */
-        if (FsContext->DeleteOnClose)
-            FsContext->DeletePending = TRUE;
-        DeletePending = FsContext->DeletePending;
-
-        /* all handles on this FileObject are gone; decrement its FsContext->OpenCount */
-        OpenCount = FspFileContextClose(FsContext);
-
-        /* unlock the FsContext */
-        ExReleaseResourceLite(FsContext->Header.Resource);
-
-        /* is the FsContext going away as well? */
-        if (0 == OpenCount)
-        {
-            /*
-             * The following must be done under the file system volume device Resource,
-             * because we are manipulating its GenericTable.
-             */
-            ExAcquireResourceExclusiveLite(&FsvolDeviceExtension->Base.Resource, TRUE);
-            try
-            {
-                /* remove the FsContext from the file system volume device generic table */
-                FspFsvolDeviceDeleteContext(DeviceObject, FsContext->UserContext, 0);
-            }
-            finally
-            {
-                ExReleaseResourceLite(&FsvolDeviceExtension->Base.Resource);
-            }
-        }
-
         /* create the user-mode file system request */
         Result = FspIopCreateRequest(Irp, FileNameRequired ? &FsContext->FileName : 0, 0, &Request);
         if (!NT_SUCCESS(Result))

src/sys/close.c

@@ -50,24 +50,24 @@ static NTSTATUS FspFsvolClose(
 
     NTSTATUS Result;
     FSP_FSVOL_DEVICE_EXTENSION *FsvolDeviceExtension = FspFsvolDeviceExtension(DeviceObject);
-    PDEVICE_OBJECT FsvrtDeviceObject = FsvolDeviceExtension->FsvrtDeviceObject;
+    PFILE_OBJECT FileObject = IrpSp->FileObject;
+    FSP_FILE_CONTEXT *FsContext = FileObject->FsContext;
+    UINT64 UserContext = FsContext->UserContext;
+    UINT64 UserContext2 = (UINT_PTR)FileObject->FsContext2;
 
+    /* dereference the FsContext (and delete if no more references) */
+    FspFileContextRelease(FsContext);
+
+    PDEVICE_OBJECT FsvrtDeviceObject = FsvolDeviceExtension->FsvrtDeviceObject;
     if (!FspDeviceRetain(FsvrtDeviceObject))
         return STATUS_CANCELLED;
+
     try
     {
-        FSP_FSVRT_DEVICE_EXTENSION *FsvrtDeviceExtension =
+        FSP_FSVRT_DEVICE_EXTENSION *FsvrtDeviceExtension = FspFsvrtDeviceExtension(FsvrtDeviceObject);
-            FspFsvrtDeviceExtension(FsvrtDeviceObject);
-        PFILE_OBJECT FileObject = IrpSp->FileObject;
-        FSP_FILE_CONTEXT *FsContext = FileObject->FsContext;
-        UINT64 UserContext = FsContext->UserContext;
-        UINT64 UserContext2 = (UINT_PTR)FileObject->FsContext2;
         BOOLEAN FileNameRequired = 0 != FsvrtDeviceExtension->VolumeParams.FileNameRequired;
         FSP_FSCTL_TRANSACT_REQ *Request;
 
-        /* dereference the FsContext (and delete if no more references) */
-        FspFileContextRelease(FsContext);
-
         /* create the user-mode file system request */
         Result = FspIopCreateRequest(0, FileNameRequired ? &FsContext->FileName : 0, 0, &Request);
         if (!NT_SUCCESS(Result))

src/sys/create.c

@@ -63,14 +63,14 @@ static NTSTATUS FspFsvolCreate(
 
     NTSTATUS Result;
     FSP_FSVOL_DEVICE_EXTENSION *FsvolDeviceExtension = FspFsvolDeviceExtension(DeviceObject);
-    PDEVICE_OBJECT FsvrtDeviceObject = FsvolDeviceExtension->FsvrtDeviceObject;
 
+    PDEVICE_OBJECT FsvrtDeviceObject = FsvolDeviceExtension->FsvrtDeviceObject;
     if (!FspDeviceRetain(FsvrtDeviceObject))
         return STATUS_CANCELLED;
+
     try
     {
-        FSP_FSVRT_DEVICE_EXTENSION *FsvrtDeviceExtension =
+        FSP_FSVRT_DEVICE_EXTENSION *FsvrtDeviceExtension = FspFsvrtDeviceExtension(FsvrtDeviceObject);
-            FspFsvrtDeviceExtension(FsvrtDeviceObject);
         PFILE_OBJECT FileObject = IrpSp->FileObject;
         PFILE_OBJECT RelatedFileObject = FileObject->RelatedFileObject;
         UNICODE_STRING FileName = FileObject->FileName;
@@ -223,7 +223,7 @@ static NTSTATUS FspFsvolCreate(
             BOOLEAN AppendBackslash =
                 sizeof(WCHAR) * 2/* not empty or root */ <= RelatedFsContext->FileName.Length &&
                 sizeof(WCHAR) <= FileName.Length && L':' != FileName.Buffer[0];
-            Result = FspFileContextCreate(
+            Result = FspFileContextCreate(DeviceObject,
                 RelatedFsContext->FileName.Length + AppendBackslash * sizeof(WCHAR) + FileName.Length,
                 &FsContext);
             if (!NT_SUCCESS(Result))
@@ -254,7 +254,7 @@ static NTSTATUS FspFsvolCreate(
                 goto exit;
             }
 
-            Result = FspFileContextCreate(
+            Result = FspFileContextCreate(DeviceObject,
                 FileName.Length,
                 &FsContext);
             if (!NT_SUCCESS(Result))

src/sys/driver.h

@@ -398,11 +398,13 @@ typedef struct
     BOOLEAN DeleteOnClose;              /* FILE_DELETE_ON_CLOSE */
     /* read-only after creation */
     FSP_DEVICE_GENERIC_TABLE_ELEMENT ElementStorage;
+    PDEVICE_OBJECT FsvolDeviceObject;
     UINT64 UserContext;
     UNICODE_STRING FileName;
     WCHAR FileNameBuf[];
 } FSP_FILE_CONTEXT;
-NTSTATUS FspFileContextCreate(ULONG ExtraSize, FSP_FILE_CONTEXT **PContext);
+NTSTATUS FspFileContextCreate(PDEVICE_OBJECT DeviceObject,
+    ULONG ExtraSize, FSP_FILE_CONTEXT **PFsContext);
 VOID FspFileContextDelete(FSP_FILE_CONTEXT *Context);
 static inline
 VOID FspFileContextOpen(FSP_FILE_CONTEXT *Context)

src/sys/fileobj.c

@@ -6,7 +6,8 @@
 
 #include <sys/driver.h>
 
-NTSTATUS FspFileContextCreate(ULONG ExtraSize, FSP_FILE_CONTEXT **PContext);
+NTSTATUS FspFileContextCreate(PDEVICE_OBJECT DeviceObject,
+    ULONG ExtraSize, FSP_FILE_CONTEXT **PFsContext);
 VOID FspFileContextDelete(FSP_FILE_CONTEXT *Context);
 
 #ifdef ALLOC_PRAGMA
@@ -14,7 +15,8 @@ VOID FspFileContextDelete(FSP_FILE_CONTEXT *Context);
 #pragma alloc_text(PAGE, FspFileContextDelete)
 #endif
 
-NTSTATUS FspFileContextCreate(ULONG ExtraSize, FSP_FILE_CONTEXT **PFsContext)
+NTSTATUS FspFileContextCreate(PDEVICE_OBJECT DeviceObject,
+    ULONG ExtraSize, FSP_FILE_CONTEXT **PFsContext)
 {
     PAGED_CODE();
 
@@ -45,6 +47,8 @@ NTSTATUS FspFileContextCreate(ULONG ExtraSize, FSP_FILE_CONTEXT **PFsContext)
     FsRtlSetupAdvancedHeader(&FsContext->Header, &NonPaged->HeaderFastMutex);
     FsContext->NonPaged = NonPaged;
     FsContext->RefCount = 1;
+    FsContext->FsvolDeviceObject = DeviceObject;
+    FspDeviceRetain(FsContext->FsvolDeviceObject);
     RtlInitEmptyUnicodeString(&FsContext->FileName, FsContext->FileNameBuf, (USHORT)ExtraSize);
 
     *PFsContext = FsContext;
@@ -58,6 +62,8 @@ VOID FspFileContextDelete(FSP_FILE_CONTEXT *FsContext)
 
     FsRtlTeardownPerStreamContexts(&FsContext->Header);
 
+    FspDeviceRelease(FsContext->FsvolDeviceObject);
+
     ExDeleteResourceLite(&FsContext->NonPaged->PagingIoResource);
     ExDeleteResourceLite(&FsContext->NonPaged->Resource);
     FspFree(FsContext->NonPaged);