lockctrl.c

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/*++

Copyright (c) 1989-2000 Microsoft Corporation

Module Name:

    LockCtrl.c

Abstract:

    This module implements the Lock Control routines for Fat called
    by the dispatch driver.


--*/

#include "FatProcs.h"

//
//  The local debug trace level
//

#define Dbg                              (DEBUG_TRACE_LOCKCTRL)

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, FatCommonLockControl)
#pragma alloc_text(PAGE, FatFastLock)
#pragma alloc_text(PAGE, FatFastUnlockAll)
#pragma alloc_text(PAGE, FatFastUnlockAllByKey)
#pragma alloc_text(PAGE, FatFastUnlockSingle)
#pragma alloc_text(PAGE, FatFsdLockControl)
#endif


NTSTATUS
FatFsdLockControl (
    IN PVOLUME_DEVICE_OBJECT VolumeDeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:

    This routine implements the FSD part of Lock control operations

Arguments:

    VolumeDeviceObject - Supplies the volume device object where the
        file exists

    Irp - Supplies the Irp being processed

Return Value:

    NTSTATUS - The FSD status for the IRP

--*/

{
    NTSTATUS Status;
    PIRP_CONTEXT IrpContext = NULL;

    BOOLEAN TopLevel;

    DebugTrace(+1, Dbg, "FatFsdLockControl\n", 0);

    //
    //  Call the common Lock Control routine, with blocking allowed if
    //  synchronous
    //

    FsRtlEnterFileSystem();

    TopLevel = FatIsIrpTopLevel( Irp );

    try {

        IrpContext = FatCreateIrpContext( Irp, CanFsdWait( Irp ) );

        Status = FatCommonLockControl( IrpContext, Irp );

    } except(FatExceptionFilter( IrpContext, 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
        //

        Status = FatProcessException( IrpContext, Irp, GetExceptionCode() );
    }

    if (TopLevel) { IoSetTopLevelIrp( NULL ); }

    FsRtlExitFileSystem();

    //
    //  And return to our caller
    //

    DebugTrace(-1, Dbg, "FatFsdLockControl -> %08lx\n", Status);

    UNREFERENCED_PARAMETER( VolumeDeviceObject );

    return Status;
}


BOOLEAN
FatFastLock (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER FileOffset,
    IN PLARGE_INTEGER Length,
    PEPROCESS ProcessId,
    ULONG Key,
    BOOLEAN FailImmediately,
    BOOLEAN ExclusiveLock,
    OUT PIO_STATUS_BLOCK IoStatus,
    IN PDEVICE_OBJECT DeviceObject
    )

/*++

Routine Description:

    This is a call back routine for doing the fast lock call.

Arguments:

    FileObject - Supplies the file object used in this operation

    FileOffset - Supplies the file offset used in this operation

    Length - Supplies the length used in this operation

    ProcessId - Supplies the process ID used in this operation

    Key - Supplies the key used in this operation

    FailImmediately - Indicates if the request should fail immediately
        if the lock cannot be granted.

    ExclusiveLock - Indicates if this is a request for an exclusive or
        shared lock

    IoStatus - Receives the Status if this operation is successful

Return Value:

    BOOLEAN - TRUE if this operation completed and FALSE if caller
        needs to take the long route.

--*/

{
    BOOLEAN Results;
    PVCB Vcb;
    PFCB Fcb;
    PCCB Ccb;

    DebugTrace(+1, Dbg, "FatFastLock\n", 0);

    //
    //  Decode the type of file object we're being asked to process and make
    //  sure it is only a user file open.
    //

    if (FatDecodeFileObject( FileObject, &Vcb, &Fcb, &Ccb ) != UserFileOpen) {

        IoStatus->Status = STATUS_INVALID_PARAMETER;
        IoStatus->Information = 0;

        DebugTrace(-1, Dbg, "FatFastLock -> TRUE (STATUS_INVALID_PARAMETER)\n", 0);
        return TRUE;
    }

    //
    //  Acquire exclusive access to the Fcb this operation can always wait
    //

    FsRtlEnterFileSystem();

    try {

        //
        //  We check whether we can proceed
        //  based on the state of the file oplocks.
        //

        if (!FsRtlOplockIsFastIoPossible( &(Fcb)->Specific.Fcb.Oplock )) {

            try_return( Results = FALSE );
        }

        //
        //  Now call the FsRtl routine to do the actual processing of the
        //  Lock request
        //

        if (Results = FsRtlFastLock( &Fcb->Specific.Fcb.FileLock,
                                     FileObject,
                                     FileOffset,
                                     Length,
                                     ProcessId,
                                     Key,
                                     FailImmediately,
                                     ExclusiveLock,
                                     IoStatus,
                                     NULL,
                                     FALSE )) {

            //
            //  Set the flag indicating if Fast I/O is possible
            //

            Fcb->Header.IsFastIoPossible = FatIsFastIoPossible( Fcb );
        }

    try_exit:  NOTHING;
    } finally {

        DebugUnwind( FatFastLock );

        //
        //  Release the Fcb, and return to our caller
        //

        FsRtlExitFileSystem();

        DebugTrace(-1, Dbg, "FatFastLock -> %08lx\n", Results);
    }

    return Results;
}


BOOLEAN
FatFastUnlockSingle (
    IN PFILE_OBJECT FileObject,
    IN PLARGE_INTEGER FileOffset,
    IN PLARGE_INTEGER Length,
    PEPROCESS ProcessId,
    ULONG Key,
    OUT PIO_STATUS_BLOCK IoStatus,
    IN PDEVICE_OBJECT DeviceObject
    )

/*++

Routine Description:

    This is a call back routine for doing the fast unlock single call.

Arguments:

    FileObject - Supplies the file object used in this operation

    FileOffset - Supplies the file offset used in this operation

    Length - Supplies the length used in this operation

    ProcessId - Supplies the process ID used in this operation

    Key - Supplies the key used in this operation

    Status - Receives the Status if this operation is successful

Return Value:

    BOOLEAN - TRUE if this operation completed and FALSE if caller
        needs to take the long route.

--*/

{
    BOOLEAN Results;
    PVCB Vcb;
    PFCB Fcb;
    PCCB Ccb;

    DebugTrace(+1, Dbg, "FatFastUnlockSingle\n", 0);

    IoStatus->Information = 0;

    //
    //  Decode the type of file object we're being asked to process and make sure
    //  it is only a user file open
    //

    if (FatDecodeFileObject( FileObject, &Vcb, &Fcb, &Ccb ) != UserFileOpen) {

        IoStatus->Status = STATUS_INVALID_PARAMETER;

        DebugTrace(-1, Dbg, "FatFastUnlockSingle -> TRUE (STATUS_INVALID_PARAMETER)\n", 0);
        return TRUE;
    }

    //
    //  Acquire exclusive access to the Fcb this operation can always wait
    //

    FsRtlEnterFileSystem();

    try {

        //
        //  We check whether we can proceed based on the state of the file oplocks.
        //

        if (!FsRtlOplockIsFastIoPossible( &(Fcb)->Specific.Fcb.Oplock )) {

            try_return( Results = FALSE );
        }

        //
        //  Now call the FsRtl routine to do the actual processing of the
        //  Lock request.  The call will always succeed.
        //

        Results = TRUE;
        IoStatus->Status = FsRtlFastUnlockSingle( &Fcb->Specific.Fcb.FileLock,
                                                  FileObject,
                                                  FileOffset,
                                                  Length,
                                                  ProcessId,
                                                  Key,
                                                  NULL,
                                                  FALSE );

        //
        //  Set the flag indicating if Fast I/O is possible
        //

        Fcb->Header.IsFastIoPossible = FatIsFastIoPossible( Fcb );

    try_exit:  NOTHING;
    } finally {

        DebugUnwind( FatFastUnlockSingle );

        //
        //  Release the Fcb, and return to our caller
        //

        FsRtlExitFileSystem();

        DebugTrace(-1, Dbg, "FatFastUnlockSingle -> %08lx\n", Results);
    }

    return Results;
}


BOOLEAN