fspdisp.c File Reference

#include "fatprocs.h"

Include dependency graph for fspdisp.c:

Go to the source code of this file.

Macros
#define	Dbg   (DEBUG_TRACE_FSP_DISPATCHER)

Functions
PVOID	FatRemoveOverflowEntry (IN PVOLUME_DEVICE_OBJECT VolDo)
VOID NTAPI	FatFspDispatch (_In_ PVOID Context)

Macro Definition Documentation

Dbg

#define Dbg   (DEBUG_TRACE_FSP_DISPATCHER)

Definition at line 32 of file fspdisp.c.

Function Documentation

FatFspDispatch()

VOID NTAPI FatFspDispatch

(

_In_ PVOID

Context

)

Definition at line 41 of file fspdisp.c.

{
    NTSTATUS Status = STATUS_SUCCESS;


    PIRP Irp;
    PIRP_CONTEXT IrpContext;
    PIO_STACK_LOCATION IrpSp;
    BOOLEAN VcbDeleted;
    BOOLEAN  ExceptionCompletedIrp = FALSE;

    PVOLUME_DEVICE_OBJECT VolDo;

    UCHAR MajorFunction = 0;

    PAGED_CODE();

    IrpContext = (PIRP_CONTEXT)Context;

    Irp = IrpContext->OriginatingIrp;

    IrpSp = IoGetCurrentIrpStackLocation( Irp );

    //
    //  Now because we are the Fsp we will force the IrpContext to
    //  indicate true on Wait.
    //

    SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT | IRP_CONTEXT_FLAG_IN_FSP);

    //
    //  If this request has an associated volume device object, remember it.
    //

    if ( IrpSp->FileObject != NULL ) {

        VolDo = CONTAINING_RECORD( IrpSp->DeviceObject,
                                   VOLUME_DEVICE_OBJECT,
                                   DeviceObject );
    } else {

        VolDo = NULL;
    }

    //
    //  Now case on the function code.  For each major function code,
    //  either call the appropriate FSP routine or case on the minor
    //  function and then call the FSP routine.  The FSP routine that
    //  we call is responsible for completing the IRP, and not us.
    //  That way the routine can complete the IRP and then continue
    //  post processing as required.  For example, a read can be
    //  satisfied right away and then read can be done.
    //
    //  We'll do all of the work within an exception handler that
    //  will be invoked if ever some underlying operation gets into
    //  trouble (e.g., if FatReadSectorsSync has trouble).
    //

    while ( TRUE ) {

        ExceptionCompletedIrp = FALSE;
                
        DebugTrace(0, Dbg, "FatFspDispatch: Irp = %p\n", Irp);

        //
        //  If this Irp was top level, note it in our thread local storage.
        //

        FsRtlEnterFileSystem();

        if ( FlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_RECURSIVE_CALL) ) {

            IoSetTopLevelIrp( (PIRP)FSRTL_FSP_TOP_LEVEL_IRP );

        } else {

            IoSetTopLevelIrp( Irp );
        }

        MajorFunction = IrpContext->MajorFunction;

        _SEH2_TRY {

            switch ( MajorFunction ) {

                //
                //  For Create Operation,
                //

                case IRP_MJ_CREATE:

                    Status = FatCommonCreate( IrpContext, Irp );
                    break;

                //
                //  For close operations.  We do a little kludge here in case
                //  this close causes a volume to go away.  It will NULL the
                //  VolDo local variable so that we will not try to look at
                //  the overflow queue.
                //

                case IRP_MJ_CLOSE:

                {
                    PVCB Vcb;
                    PFCB Fcb;
                    PCCB Ccb;
                    TYPE_OF_OPEN TypeOfOpen;

                    //
                    //  Extract and decode the file object
                    //

                    TypeOfOpen = FatDecodeFileObject( IrpSp->FileObject, &Vcb, &Fcb, &Ccb );

                    //
                    //  Do the close.  We have a slightly different format
                    //  for this call because of the async closes.
                    //

                    Status = FatCommonClose( Vcb,
                                             Fcb,
                                             Ccb,
                                             TypeOfOpen,
                                             TRUE,
                                             TRUE,
                                             &VcbDeleted );

                    //
                    //  If the VCB was deleted, do not try to access it later.
                    //

                    if (VcbDeleted) {

                        VolDo = NULL;
                    }

                    NT_ASSERT(Status == STATUS_SUCCESS);

                    FatCompleteRequest( IrpContext, Irp, Status );

                    break;
                }

                //
                //  For read operations
                //

                case IRP_MJ_READ:

                    (VOID) FatCommonRead( IrpContext, Irp );
                    break;

                //
                //  For write operations,
                //

                case IRP_MJ_WRITE:

                    (VOID) FatCommonWrite( IrpContext, Irp );
                    break;

                //
                //  For Query Information operations,
                //

                case IRP_MJ_QUERY_INFORMATION:

                    (VOID) FatCommonQueryInformation( IrpContext, Irp );
                    break;

                //
                //  For Set Information operations,
                //

                case IRP_MJ_SET_INFORMATION:

                    (VOID) FatCommonSetInformation( IrpContext, Irp );
                    break;

                //
                //  For Query EA operations,
                //

                case IRP_MJ_QUERY_EA:

                    (VOID) FatCommonQueryEa( IrpContext, Irp );
                    break;

                //
                //  For Set EA operations,
                //

                case IRP_MJ_SET_EA:

                    (VOID) FatCommonSetEa( IrpContext, Irp );
                    break;

                //
                //  For Flush buffers operations,
                //

                case IRP_MJ_FLUSH_BUFFERS:

                    (VOID) FatCommonFlushBuffers( IrpContext, Irp );
                    break;

                //
                //  For Query Volume Information operations,
                //

                case IRP_MJ_QUERY_VOLUME_INFORMATION:

                    (VOID) FatCommonQueryVolumeInfo( IrpContext, Irp );
                    break;

                //
                //  For Set Volume Information operations,
                //

                case IRP_MJ_SET_VOLUME_INFORMATION:

                    (VOID) FatCommonSetVolumeInfo( IrpContext, Irp );
                    break;

                //
                //  For File Cleanup operations,
                //

                case IRP_MJ_CLEANUP:

                    (VOID) FatCommonCleanup( IrpContext, Irp );
                    break;

                //
                //  For Directory Control operations,
                //

                case IRP_MJ_DIRECTORY_CONTROL:

                    (VOID) FatCommonDirectoryControl( IrpContext, Irp );
                    break;

                //
                //  For File System Control operations,
                //

                case IRP_MJ_FILE_SYSTEM_CONTROL:

                    (VOID) FatCommonFileSystemControl( IrpContext, Irp );
                    break;

                //
                //  For Lock Control operations,
                //

                case IRP_MJ_LOCK_CONTROL:

                    (VOID) FatCommonLockControl( IrpContext, Irp );
                    break;

                //
                //  For Device Control operations,
                //

                case IRP_MJ_DEVICE_CONTROL:

                    (VOID) FatCommonDeviceControl( IrpContext, Irp );
                    break;

                //
                //  For the Shutdown operation,
                //

                case IRP_MJ_SHUTDOWN:

                    (VOID) FatCommonShutdown( IrpContext, Irp );
                    break;

                //
                //  For plug and play operations.
                //

                case IRP_MJ_PNP:

                    //
                    //  I don't believe this should ever occur, but allow for the unexpected.
                    //

                    (VOID) FatCommonPnp( IrpContext, Irp );
                    break;

                //
                //  For any other major operations, return an invalid
                //  request.
                //

                default:

                    FatCompleteRequest( IrpContext, Irp, STATUS_INVALID_DEVICE_REQUEST );
                    break;

            }

        } _SEH2_EXCEPT(FatExceptionFilter( IrpContext, _SEH2_GetExceptionInformation() )) {

            //
            //  We had some trouble trying to perform the requested
            //  operation, so we'll abort the I/O request with
            //  the error status that we get back from the
            //  execption code.
            //

            (VOID) FatProcessException( IrpContext, Irp, _SEH2_GetExceptionCode() );
            ExceptionCompletedIrp = TRUE;
        } _SEH2_END;

        IoSetTopLevelIrp( NULL );

        FsRtlExitFileSystem();


        if (MajorFunction == IRP_MJ_CREATE && !ExceptionCompletedIrp && Status != STATUS_PENDING) {
            
            //
            // Creates are completed here. IrpContext is also freed here.
            //

            FatCompleteRequest( IrpContext, Irp, Status );            
        }

        //
        //  If there are any entries on this volume's overflow queue, service
        //  them.
        //

        if ( VolDo != NULL ) {

            PVOID Entry;

            //
            //  We have a volume device object so see if there is any work
            //  left to do in its overflow queue.
            //

            Entry = FatRemoveOverflowEntry( VolDo );

            //
            //  There wasn't an entry, break out of the loop and return to
            //  the Ex Worker thread.
            //

            if ( Entry == NULL ) {

                break;
            }

            //
            //  Extract the IrpContext, Irp, and IrpSp, and loop.
            //

            IrpContext = CONTAINING_RECORD( Entry,
                                            IRP_CONTEXT,
                                            WorkQueueItem.List );

            SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT | IRP_CONTEXT_FLAG_IN_FSP);

            Irp = IrpContext->OriginatingIrp;

            IrpSp = IoGetCurrentIrpStackLocation( Irp );

            continue;

        } else {

            break;
        }
    }

    return;
}

FatRemoveOverflowEntry()

PVOID FatRemoveOverflowEntry

(

IN PVOLUME_DEVICE_OBJECT

VolDo

)

Definition at line 452 of file fspdisp.c.

{
    PVOID Entry;
    KIRQL SavedIrql;

    KeAcquireSpinLock( &VolDo->OverflowQueueSpinLock, &SavedIrql );

    if (VolDo->OverflowQueueCount > 0) {

        //
        //  There is overflow work to do in this volume so we'll
        //  decrement the Overflow count, dequeue the IRP, and release
        //  the Event
        //

        VolDo->OverflowQueueCount -= 1;

        Entry = RemoveHeadList( &VolDo->OverflowQueue );

    } else {

        VolDo->PostedRequestCount -= 1;

        Entry = NULL;
    }

    KeReleaseSpinLock( &VolDo->OverflowQueueSpinLock, SavedIrql );

    return Entry;
}

Referenced by FatFspDispatch().