pnp.c

windows 2000中的UDF文件系统的驱动程序.只有读的功能,不支持未关闭的盘片.只支持UDF2.0以下版本,不支持VAT格式的UDF.

    
Arguments:

    Irp - Supplies the Irp to process
    
    Vcb - Supplies the volume being removed.

Return Value:

    NTSTATUS - The return status for the operation

--*/

{
    NTSTATUS Status;
    KEVENT Event;
    BOOLEAN VcbPresent = TRUE;
    
    //
    //  REMOVE - a storage device is now gone.  We either got
    //  QUERY'd and said yes OR got a SURPRISE OR a storage
    //  stack failed to spin back up from a sleep/stop state
    //  (the only case in which this will be the first warning).
    //
    //  Note that it is entirely unlikely that we will be around
    //  for a REMOVE in the first two cases, as we try to intiate
    //  dismount.
    //
    
    //
    //  Acquire the global resource so that we can try to vaporize
    //  the volume, and the vcb resource itself.
    //
    
    UdfAcquireUdfData( IrpContext );
    UdfAcquireVcbExclusive( IrpContext, Vcb, FALSE );

    //
    //  The device will be going away.  Remove our lock and find
    //  out if we ever had one in the first place.
    //

    Status = UdfUnlockVolumeInternal( IrpContext, Vcb, NULL );

    //
    //  If the volume had not been locked, we must invalidate the
    //  volume to ensure it goes away properly.  The remove will
    //  succeed.
    //

    if (!NT_SUCCESS( Status )) {

        UdfLockVcb( IrpContext, Vcb );
        
        if (Vcb->VcbCondition != VcbDismountInProgress) {
            Vcb->VcbCondition = VcbInvalid;
        }
        
        UdfUnlockVcb( IrpContext, Vcb );
        
        Status = STATUS_SUCCESS;
    }
    
    //
    //  We need to pass this down before starting the dismount, which
    //  could disconnect us immediately from the stack.
    //
    
    //
    //  Get the next stack location, and copy over the stack location
    //

    IoCopyCurrentIrpStackLocationToNext( Irp );

    //
    //  Set up the completion routine
    //

    KeInitializeEvent( &Event, NotificationEvent, FALSE );
    IoSetCompletionRoutine( Irp,
                            UdfPnpCompletionRoutine,
                            &Event,
                            TRUE,
                            TRUE,
                            TRUE );

    //
    //  Send the request and wait.
    //

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

    if (Status == STATUS_PENDING) {

        KeWaitForSingleObject( &Event,
                               Executive,
                               KernelMode,
                               FALSE,
                               NULL );

        Status = Irp->IoStatus.Status;
    }

    //
    //  Now make our dismount happen.  This may not vaporize the
    //  Vcb, of course, since there could be any number of handles
    //  outstanding if we were not preceeded by a QUERY.
    //
    //  PnP will take care of disconnecting this stack if we
    //  couldn't get off of it immediately.
    //

    VcbPresent = UdfCheckForDismount( IrpContext, Vcb, TRUE );

    //
    //  Release the Vcb if it could still remain.
    //
    
    if (VcbPresent) {

        UdfReleaseVcb( IrpContext, Vcb );
    }

    UdfReleaseUdfData( IrpContext );
    
    //
    //  Cleanup our IrpContext and complete the IRP.
    //

    UdfCompleteRequest( IrpContext, Irp, Status );

    return Status;
}


NTSTATUS
UdfPnpSurpriseRemove (
    PIRP_CONTEXT IrpContext,
    PIRP Irp,
    PVCB Vcb
    )

/*++

Routine Description:

    This routine handles the PnP surprise remove operation.  This is another
    type of notification that the underlying storage device for the volume we
    have is gone, and is excellent indication that the volume will never reappear.
    The filesystem is responsible for initiation or completion the dismount.
    
    For the most part, only "real" drivers care about the distinction of a
    surprise remove, which is a result of our noticing that a user (usually)
    physically reached into the machine and pulled something out.
    
    Surprise will be followed by a Remove when all references have been shut down.

Arguments:

    Irp - Supplies the Irp to process
    
    Vcb - Supplies the volume being removed.

Return Value:

    NTSTATUS - The return status for the operation

--*/

{
    NTSTATUS Status;
    KEVENT Event;
    BOOLEAN VcbPresent = TRUE;
    
    //
    //  SURPRISE - a device was physically yanked away without
    //  any warning.  This means external forces.
    //
    
    UdfAcquireUdfData( IrpContext );
    UdfAcquireVcbExclusive( IrpContext, Vcb, FALSE );
        
    //
    //  Invalidate the volume right now.
    //
    //  The intent here is to make every subsequent operation
    //  on the volume fail and grease the rails toward dismount.
    //  By definition there is no going back from a SURPRISE.
    //
        
    UdfLockVcb( IrpContext, Vcb );
    
    if (Vcb->VcbCondition != VcbDismountInProgress) {
        Vcb->VcbCondition = VcbInvalid;
    }
    
    UdfUnlockVcb( IrpContext, Vcb );
    
    //
    //  We need to pass this down before starting the dismount, which
    //  could disconnect us immediately from the stack.
    //
    
    //
    //  Get the next stack location, and copy over the stack location
    //

    IoCopyCurrentIrpStackLocationToNext( Irp );

    //
    //  Set up the completion routine
    //

    KeInitializeEvent( &Event, NotificationEvent, FALSE );
    IoSetCompletionRoutine( Irp,
                            UdfPnpCompletionRoutine,
                            &Event,
                            TRUE,
                            TRUE,
                            TRUE );

    //
    //  Send the request and wait.
    //

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

    if (Status == STATUS_PENDING) {

        KeWaitForSingleObject( &Event,
                               Executive,
                               KernelMode,
                               FALSE,
                               NULL );

        Status = Irp->IoStatus.Status;
    }
    
    //
    //  Now make our dismount happen.  This may not vaporize the
    //  Vcb, of course, since there could be any number of handles
    //  outstanding since this is an out of band notification.
    //

    VcbPresent = UdfCheckForDismount( IrpContext, Vcb, TRUE );
    
    //
    //  Release the Vcb if it could still remain.
    //
    
    if (VcbPresent) {

        UdfReleaseVcb( IrpContext, Vcb );
    }

    UdfReleaseUdfData( IrpContext );
    
    //
    //  Cleanup our IrpContext and complete the IRP.
    //

    UdfCompleteRequest( IrpContext, Irp, Status );

    return Status;
}


NTSTATUS
UdfPnpCancelRemove (
    PIRP_CONTEXT IrpContext,
    PIRP Irp,
    PVCB Vcb
    )

/*++

Routine Description:

    This routine handles the PnP cancel remove operation.  This is our
    notification that a previously proposed remove (query) was eventually
    vetoed by a component.  The filesystem is responsible for cleaning up
    and getting ready for more IO.
    
Arguments:

    Irp - Supplies the Irp to process
    
    Vcb - Supplies the volume being removed.

Return Value:

    NTSTATUS - The return status for the operation

--*/

{
    NTSTATUS Status;

    //
    //  CANCEL - a previous QUERY has been rescinded as a result
    //  of someone vetoing.  Since PnP cannot figure out who may
    //  have gotten the QUERY (think about it: stacked drivers),
    //  we must expect to deal with getting a CANCEL without having
    //  seen the QUERY.
    //
    //  For UDFS, this is quite easy.  In fact, we can't get a
    //  CANCEL if the underlying drivers succeeded the QUERY since
    //  we disconnect the Vpb on our dismount initiation.  This is
    //  actually pretty important because if PnP could get to us
    //  after the disconnect we'd be thoroughly unsynchronized
    //  with respect to the Vcb getting torn apart - merely referencing
    //  the volume device object is insufficient to keep us intact.
    //
    
    UdfAcquireVcbExclusive( IrpContext, Vcb, FALSE );
    
    //
    //  Unlock the volume.  This is benign if we never had seen
    //  a QUERY.
    //

    (VOID) UdfUnlockVolumeInternal( IrpContext, Vcb, NULL );

    UdfReleaseVcb( IrpContext, Vcb );

    //
    //  Send the request.  The underlying driver will complete the
    //  IRP.  Since we don't need to be in the way, simply ellide
    //  ourselves out of the IRP stack.
    //

    IoSkipCurrentIrpStackLocation( Irp );

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

    UdfCompleteRequest( IrpContext, NULL, STATUS_SUCCESS );

    return Status;
}


//
//  Local support routine
//

NTSTATUS
UdfPnpCompletionRoutine (
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp,
    IN PVOID Contxt
    )
{
    PKEVENT Event = (PKEVENT) Contxt;

    KeSetEvent( Event, 0, FALSE );

    return STATUS_MORE_PROCESSING_REQUIRED;

    UNREFERENCED_PARAMETER( DeviceObject );
    UNREFERENCED_PARAMETER( Contxt );
}