NLGetFullPathName获取cmd.exe创建文件路径的问题

我主要想在IRP_MJ_CREATE完成之前得到全路径，用NLGetFullPathName这个函数可以，但是用cmd.exe创建文件或目录的时候，NLGetFullPathName返回STATUS_UNSUCCESSFUL，跟了下是RelatedFileObject不为空的情况，实际上它取到了文件路径，但是要返回STATUS_UNSUCCESSFUL，求解释~~~
下面是NLGetFullPathName处理含RelatedFileObjec的部分代码，最后它说：
        //
        //  Continue on to the end of the routine and return
        //  STATUS_UNSUCCESSFUL since we are not able to return a "usable"
        //  file name (caller cannot use the file name we return in other
        //  calls because it is not "valid").
        //

        returnValue = STATUS_UNSUCCESSFUL;
什么意思啊？

  

//
    //  CASE 3: We are opening a file that has a RelatedFileObject.
    //

    else if (FlagOn( LookupFlags, NLFL_IN_CREATE ) &&
             (NULL != FileObject->RelatedFileObject)) {

        //
        //  Must be a relative open.  We cannot use ObQueryNameString to get
        //  the name of the RelatedFileObject because it may result in
        //  deadlock.
        //

        PNAME_CONTROL relativeName;
        ULONG returnLength;

        status = NLAllocateNameControl( &relativeName, LookasideList );

        if (!NT_SUCCESS( status )) {

            goto NoResources;
        }

        status = NLPQueryFileSystemForFileName( FileObject->RelatedFileObject,
                                                NLExtHeader->AttachedToDeviceObject,
                                                relativeName );

        if (NT_SUCCESS( status ))
        {

            //
            //  We were able to get the relative FileoBject's name.
            //  Build up the file name in the following format:
            //      [volumeName]\[relativeFileObjectName]\[FileObjectName]
            //  The VolumeName is already in FileNameControl if we've got one.
            //

            status = NLCheckAndGrowNameControl( FileNameControl,
                                                FileNameControl->Name.Length +
                                                relativeName->Name.Length );

            if (!NT_SUCCESS( status )) {

                goto NoResources;
            }

            RtlAppendUnicodeStringToString( &FileNameControl->Name,
                                            &relativeName->Name );

        } else {

            //
            //  The query for the relative FileObject name was
            //  unsuccessful. Build up the file name in the following format:
            //      [volumeName]\...\[FileObjectName]
            //  The volumeName is already in FileNameControl if we've got one.

#           define RFOPlaceholder L"...\\"

            status = NLCheckAndGrowNameControl( FileNameControl,
                                                FileNameControl->Name.Length +
                                                sizeof( RFOPlaceholder ) );

            if (!NT_SUCCESS( status )) {

                goto NoResources;
            }

            RtlAppendUnicodeToString( &FileNameControl->Name,
                                      RFOPlaceholder );

            cacheName = FALSE;

        }

        //
        //  If there is not a slash and the end of the related file object
        //  string and there is not a slash at the front of the file object
        //  string, then add one.
        //

        if (((FileNameControl->Name.Length < sizeof(WCHAR) ||
             (FileNameControl->Name.Buffer[(FileNameControl->Name.Length/sizeof(WCHAR))-1] != L'\\')))
             && ((FileObject->FileName.Length < sizeof(WCHAR)) ||
             (FileObject->FileName.Buffer[0] != L'\\')))
        {

            status = NLCheckAndGrowNameControl( FileNameControl,
                                                FileNameControl->Name.Length +
                                                sizeof(WCHAR) );

            if (!NT_SUCCESS( status )) {

                goto NoResources;
            }

            RtlAppendUnicodeToString( &FileNameControl->Name, L"\\" );
        }

        NLFreeNameControl( relativeName, LookasideList );

        //
        //  At this time, copy over the FileObject->FileName to FileNameControl.
        //

        status = NLCheckAndGrowNameControl( FileNameControl,
                                            FileNameControl->Name.Length +
                                            FileObject->FileName.Length );

        if (!NT_SUCCESS( status )) {

            goto NoResources;
        }

        RtlAppendUnicodeStringToString( &FileNameControl->Name,
                                        &FileObject->FileName );

        //
        //  Continue on to the end of the routine and return
        //  STATUS_UNSUCCESSFUL since we are not able to return a "usable"
        //  file name (caller cannot use the file name we return in other
        //  calls because it is not "valid").
        //

        returnValue = STATUS_UNSUCCESSFUL;

    }

你跟一下啥原因嘛.既然可以跟,那就是有原因了.