pnp.c

winddk src目录下的文件系统驱动源码压缩!

            //
            //  Now if no one below us failed already, initiate the dismount
            //  on this volume, make it go away.  PnP needs to see our internal
            //  streams close and drop their references to the target device.
            //
            //  Since we were able to lock the volume, we are guaranteed to
            //  move this volume into dismount state and disconnect it from
            //  the underlying storage stack.  The force on our part is actually
            //  unnecesary, though complete.
            //
            //  What is not strictly guaranteed, though, is that the closes
            //  for the metadata streams take effect synchronously underneath
            //  of this call.  This would leave references on the target device
            //  even though we are disconnected!
            //

            if (NT_SUCCESS( Status )) {

                VcbDeleted = FatCheckForDismount( IrpContext, Vcb, TRUE );

                ASSERT( VcbDeleted || Vcb->VcbCondition == VcbBad );

            }
        }

    } finally {
        
        //
        //  Release the Vcb if it could still remain.
        //

        if (!VcbDeleted) {

            FatReleaseVcb( IrpContext, Vcb );
        }

        if (GlobalHeld) {
            
            FatReleaseGlobal( IrpContext );
        }
    }
    
    //
    //  Cleanup our IrpContext and complete the IRP if neccesary.
    //

    FatCompleteRequest( IrpContext, Irp, Status );

    return Status;
}

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

/*++

Routine Description:

    This routine handles the PnP remove operation.  This is our notification
    that the underlying storage device for the volume we have is gone, and
    an excellent indication that the volume will never reappear. The filesystem
    is responsible for initiation or completion of the dismount.
    
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 VcbDeleted;
    
    //
    //  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.
    //

    FatAcquireExclusiveVcb( IrpContext, Vcb );

    //
    //  The device will be going away.  Remove our lock (benign
    //  if we never had it).
    //

    (VOID) FatUnlockVolumeInternal( IrpContext, Vcb, NULL );
    
    //
    //  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,
                            FatPnpCompletionRoutine,
                            &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;
    }

    try {
        
        //
        //  Knock as many files down for this volume as we can.
        //

        FatFlushAndCleanVolume( IrpContext, Irp, Vcb, NoFlush );

        //
        //  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.
        //

        VcbDeleted = FatCheckForDismount( IrpContext, Vcb, TRUE );

    } finally {
        
        //
        //  Release the Vcb if it could still remain.
        //

        if (!VcbDeleted) {

            FatReleaseVcb( IrpContext, Vcb );
        }

        FatReleaseGlobal( IrpContext );
    }

    //
    //  Cleanup our IrpContext and complete the IRP.
    //

    FatCompleteRequest( IrpContext, Irp, Status );

    return Status;
}


NTSTATUS
FatPnpSurpriseRemove (
    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 VcbDeleted;
    
    //
    //  SURPRISE - a device was physically yanked away without
    //  any warning.  This means external forces.
    //
    
    FatAcquireExclusiveVcb( 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,
                            FatPnpCompletionRoutine,
                            &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;
    }
    
    try {
        
        //
        //  Knock as many files down for this volume as we can.
        //

        FatFlushAndCleanVolume( IrpContext, Irp, Vcb, NoFlush );

        //
        //  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.
        //

        VcbDeleted = FatCheckForDismount( IrpContext, Vcb, TRUE );

    } finally {
        
        //
        //  Release the Vcb if it could still remain.
        //

        if (!VcbDeleted) {

            FatReleaseVcb( IrpContext, Vcb );
        }

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

    FatCompleteRequest( IrpContext, Irp, Status );

    return Status;
}


NTSTATUS
FatPnpCancelRemove (
    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 FAT, 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.
    //
    
    FatAcquireExclusiveVcb( IrpContext, Vcb );
    FatReleaseGlobal( IrpContext);
    
    //
    //  Unlock the volume.  This is benign if we never had seen
    //  a QUERY.
    //

    Status = FatUnlockVolumeInternal( IrpContext, Vcb, NULL );

    try {
        
        //
        //  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);
    } 
    finally {
        
        FatReleaseVcb( IrpContext, Vcb );
    }

    FatCompleteRequest( IrpContext, NULL, STATUS_SUCCESS );

    return Status;
}


//
//  Local support routine
//

NTSTATUS
FatPnpCompletionRoutine (
    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 );
}