readwrit.c

Windows内核级文件系统访问操作驱动程序

/*++

Copyright (c) Microsoft Corporation. All rights reserved. 

You may only use this code if you agree to the terms of the Windows Research Kernel Source Code License agreement (see License.txt).
If you do not agree to the terms, do not use the code.


Module Name:

    ReadWrit.c

Abstract:

    This module implements the File Read and Write routines called by the
    dispatch driver.

--*/

#include "RawProcs.h"

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, RawReadWriteDeviceControl)
#endif

NTSTATUS
RawReadWriteDeviceControl (
    IN PVCB Vcb,
    IN PIRP Irp,
    IN PIO_STACK_LOCATION IrpSp
    )

/*++

Routine Description:

    This is the a common routine for both reading and writing a volume.

Arguments:

    Vcb - Supplies the volume being queried.

    Irp - Supplies the Irp to process

    IrpSp - Supplies parameters describing the read or write

Return Value:

    NTSTATUS - The return status for the operation

--*/

{
    PIO_STACK_LOCATION NextIrpSp;
    NTSTATUS Status;

    PAGED_CODE();

    //
    //  If this was for a zero byte read or write transfer, just complete
    //  it with success.
    //

    if (((IrpSp->MajorFunction == IRP_MJ_READ) ||
         (IrpSp->MajorFunction == IRP_MJ_WRITE)) &&
        (IrpSp->Parameters.Read.Length == 0)) {

        RawCompleteRequest( Irp, STATUS_SUCCESS );

        return STATUS_SUCCESS;
    }

    //
    //  This is a very simple operation.  Simply forward the
    //  request to the device driver since exact blocks are
    //  being read and return whatever status was given.
    //
    //  Get the next stack location, and copy over the stack location
    //

    NextIrpSp = IoGetNextIrpStackLocation( Irp );

    *NextIrpSp = *IrpSp;

    //
    //  Prohibit verifies all together.
    //

    NextIrpSp->Flags |= SL_OVERRIDE_VERIFY_VOLUME;

    //
    //  Set up the completion routine
    //

    IoSetCompletionRoutine( Irp,
                            RawCompletionRoutine,
                            NULL,
                            TRUE,
                            TRUE,
                            TRUE );

    //
    //  Send the request.
    //

    Status = IoCallDriver(Vcb->TargetDeviceObject, Irp);

    return Status;

}