弱问 发 iirp 写文件

我用这段代码向 fsd 发irp 来写文件， 可是会出错， 有时是 “延缓写入失败” 有时候是 ntfs! Xxxxxx   bug check  ，类似的读文件 就没有问题， 请问 有什么问题呢 ？

 

NTSTATUS
IoCompletionRoutine(
  IN PDEVICE_OBJECT  DeviceObject,
  IN PIRP  Irp,
  IN PVOID  Context
  )
{
  *Irp->UserIosb = Irp->IoStatus;

  if (Irp->UserEvent)
    KeSetEvent(Irp->UserEvent, IO_NO_INCREMENT, 0);

  if (Irp->MdlAddress)
  {
    IoFreeMdl(Irp->MdlAddress);
    Irp->MdlAddress = NULL;
  }

  IoFreeIrp(Irp);

  return STATUS_MORE_PROCESSING_REQUIRED;
}



NTSTATUS
IrpFileWrite(
  IN PDEVICE_OBJECT DeviceObject,
  IN PFILE_OBJECT FileObject,
  IN PLARGE_INTEGER ByteOffset OPTIONAL,
  IN ULONG Length,
  IN PVOID Buffer,
  OUT PIO_STATUS_BLOCK IoStatusBlock
  )
{
  NTSTATUS status;
  KEVENT event;
  PIRP irp;
  PIO_STACK_LOCATION irpSp;
  IO_STATUS_BLOCK ioStatus;

  if (ByteOffset == NULL)
  {
    if (!(FileObject->Flags & FO_SYNCHRONOUS_IO))
      return STATUS_INVALID_PARAMETER;

    ByteOffset = &FileObject->CurrentByteOffset;
  }

  if (FileObject->Vpb == 0 || FileObject->Vpb->RealDevice == NULL)
    return STATUS_UNSUCCESSFUL;

  //deviceObject = FileObject->Vpb->DeviceObject;
  irp = IoAllocateIrp(DeviceObject->StackSize, FALSE);

  if (irp == NULL)
    return STATUS_INSUFFICIENT_RESOURCES;

  irp->MdlAddress = IoAllocateMdl(Buffer, Length, FALSE, TRUE, NULL);

  if (irp->MdlAddress == NULL)
  {
    IoFreeIrp(irp);
    return STATUS_INSUFFICIENT_RESOURCES;;
  }

  MmBuildMdlForNonPagedPool(irp->MdlAddress);

  irp->Flags = IRP_WRITE_OPERATION;
  irp->RequestorMode = KernelMode;
  irp->UserIosb = &ioStatus;
  irp->UserEvent = &event;
  irp->Tail.Overlay.Thread = (PETHREAD)KeGetCurrentThread();
  irp->Tail.Overlay.OriginalFileObject = FileObject;

  irpSp = IoGetNextIrpStackLocation(irp);
  irpSp->MajorFunction = IRP_MJ_WRITE;
  irpSp->MinorFunction = IRP_MN_NORMAL;
  irpSp->DeviceObject = DeviceObject ;
  irpSp->FileObject = FileObject;
  irpSp->Parameters.Write.Length = Length;
  irpSp->Parameters.Write.ByteOffset = *ByteOffset;

  KeInitializeEvent(&event, SynchronizationEvent, FALSE);
  IoSetCompletionRoutine(irp, IoCompletionRoutine, NULL, TRUE, TRUE, TRUE);
  status = IoCallDriver(DeviceObject , irp);

  if (status == STATUS_PENDING)
    status = KeWaitForSingleObject(&event, Executive, KernelMode, TRUE, NULL);
  
  
  status = ioStatus.Status ;

  *IoStatusBlock = ioStatus;

  return status;
}

irp->Flags = IRP_WRITE_OPERATION;
(IRP_PAGING_IO|IRP_SYNCHRONOUS_PAGING_IO|IRP_NOCACHE)

还有FileObject的偏移量你也没处理好……

小弟初学， 麻烦能稍微解释一下吗， 谢谢

自己在论坛上多搜搜就有了

不好意思, 还是没搞懂, 恳求解释,  不胜感谢

论坛上有发irp处理的完整源码的

楼主用的好像就是这段代码。

那为什么会出错呢

那为什么会出错呢 ?

我发现是 process 为 system 时才出错

JeTus 说的很对！！！！
在 IrpWriteFile里面设：
Irp->Flags = IRP_PAGING_IO|IRP_SYNCHRONOUS_PAGING_IO|IRP_NOCACHE;

同时注意，要配合写IrpSetInformationFile，否则写了白写，大小还是不变。