close.c

winddk src目录下的文件系统驱动源码压缩!

    Wait - If this is TRUE we are allowed to block for the Vcb, if FALSE
        then we must try to acquire the Vcb anyway.

    VcbDeleted - Returns whether the VCB was deleted by this call.

Return Value:

    NTSTATUS - The return status for the operation

--*/

{
    NTSTATUS Status;
    PDCB ParentDcb;
    BOOLEAN RecursiveClose;
    BOOLEAN LocalVcbDeleted;
    IRP_CONTEXT IrpContext;

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

    //
    //  Initailize the callers variable, if needed.
    //

    LocalVcbDeleted = FALSE;

    if (ARGUMENT_PRESENT( VcbDeleted )) {

        *VcbDeleted = LocalVcbDeleted;
    }

    //
    //  Special case the unopened file object
    //

    if (TypeOfOpen == UnopenedFileObject) {

        DebugTrace(0, Dbg, "Close unopened file object\n", 0);

        Status = STATUS_SUCCESS;

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

    //
    //  Set up our stack IrpContext.
    //

    RtlZeroMemory( &IrpContext, sizeof(IRP_CONTEXT) );

    IrpContext.NodeTypeCode = FAT_NTC_IRP_CONTEXT;
    IrpContext.NodeByteSize = sizeof( IrpContext );
    IrpContext.MajorFunction = IRP_MJ_CLOSE;
    IrpContext.Vcb = Vcb;
    
    if (Wait) {

        SetFlag( IrpContext.Flags, IRP_CONTEXT_FLAG_WAIT );
    }

    //
    //  Acquire exclusive access to the Vcb and enqueue the irp if we didn't
    //  get access.
    //

    if (!ExAcquireResourceExclusiveLite( &Vcb->Resource, Wait )) {

        return STATUS_PENDING;
    }

    //
    //  The following test makes sure that we don't blow away an Fcb if we
    //  are trying to do a Supersede/Overwrite open above us.  This test
    //  does not apply for the EA file.
    //

    if (FlagOn(Vcb->VcbState, VCB_STATE_FLAG_CREATE_IN_PROGRESS) &&
        Vcb->EaFcb != Fcb) {

        ExReleaseResourceLite( &Vcb->Resource );

        return STATUS_PENDING;
    }

    //
    //  Setting the following flag prevents recursive closes of directory file
    //  objects, which are handled in a special case loop.
    //

    if ( FlagOn(Vcb->VcbState, VCB_STATE_FLAG_CLOSE_IN_PROGRESS) ) {

        RecursiveClose = TRUE;

    } else {

        SetFlag(Vcb->VcbState, VCB_STATE_FLAG_CLOSE_IN_PROGRESS);
        RecursiveClose = FALSE;

        //
        //  Since we are at the top of the close chain, we need to add
        //  a reference to the VCB.  This will keep it from going away
        //  on us until we are ready to check for a dismount below.
        //

        Vcb->OpenFileCount += 1;
    }

    try {

        //
        //  Case on the type of open that we are trying to close.
        //

        switch (TypeOfOpen) {

        case VirtualVolumeFile:

            DebugTrace(0, Dbg, "Close VirtualVolumeFile\n", 0);

            //
            //  Remove this internal, residual open from the count.
            //

            InterlockedDecrement( &(Vcb->InternalOpenCount) );
            InterlockedDecrement( &(Vcb->ResidualOpenCount) );

            try_return( Status = STATUS_SUCCESS );
            break;

        case UserVolumeOpen:

            DebugTrace(0, Dbg, "Close UserVolumeOpen\n", 0);

            Vcb->DirectAccessOpenCount -= 1;
            Vcb->OpenFileCount -= 1;
            if (FlagOn(Ccb->Flags, CCB_FLAG_READ_ONLY)) { Vcb->ReadOnlyCount -= 1; }

            FatDeleteCcb( &IrpContext, &Ccb );

            try_return( Status = STATUS_SUCCESS );
            break;

        case EaFile:

            DebugTrace(0, Dbg, "Close EaFile\n", 0);

            //
            //  Remove this internal, residual open from the count.
            //

            InterlockedDecrement( &(Vcb->InternalOpenCount) );
            InterlockedDecrement( &(Vcb->ResidualOpenCount) );

            try_return( Status = STATUS_SUCCESS );
            break;

        case DirectoryFile:

            DebugTrace(0, Dbg, "Close DirectoryFile\n", 0);

            InterlockedDecrement( &Fcb->Specific.Dcb.DirectoryFileOpenCount );

            //
            //  Remove this internal open from the count.
            //

            InterlockedDecrement( &(Vcb->InternalOpenCount) );

            //
            //  If this is the root directory, it is a residual open
            //  as well.
            //

            if (NodeType( Fcb ) == FAT_NTC_ROOT_DCB) {

                InterlockedDecrement( &(Vcb->ResidualOpenCount) );
            }

            //
            //  If this is a recursive close, just return here.
            //

            if ( RecursiveClose ) {

                try_return( Status = STATUS_SUCCESS );

            } else {

                break;
            }

        case UserDirectoryOpen:
        case UserFileOpen:

            DebugTrace(0, Dbg, "Close UserFileOpen/UserDirectoryOpen\n", 0);

            //
            //  Uninitialize the cache map if we no longer need to use it
            //

            if ((NodeType(Fcb) == FAT_NTC_DCB) &&
                IsListEmpty(&Fcb->Specific.Dcb.ParentDcbQueue) &&
                (Fcb->OpenCount == 1) &&
                (Fcb->Specific.Dcb.DirectoryFile != NULL)) {

                PFILE_OBJECT DirectoryFileObject = Fcb->Specific.Dcb.DirectoryFile;

                DebugTrace(0, Dbg, "Uninitialize the stream file object\n", 0);

                CcUninitializeCacheMap( DirectoryFileObject, NULL, NULL );

                //
                //  Dereference the directory file.  This may cause a close
                //  Irp to be processed, so we need to do this before we destory
                //  the Fcb.
                //

                Fcb->Specific.Dcb.DirectoryFile = NULL;
                ObDereferenceObject( DirectoryFileObject );
            }

            Fcb->OpenCount -= 1;
            Vcb->OpenFileCount -= 1;
            if (FlagOn(Ccb->Flags, CCB_FLAG_READ_ONLY)) { Vcb->ReadOnlyCount -= 1; }

            FatDeleteCcb( &IrpContext, &Ccb );

            break;

        default:

            FatBugCheck( TypeOfOpen, 0, 0 );
        }

        //
        //  At this point we've cleaned up any on-disk structure that needs
        //  to be done, and we can now update the in-memory structures.
        //  Now if this is an unreferenced FCB or if it is
        //  an unreferenced DCB (not the root) then we can remove
        //  the fcb and set our ParentDcb to non null.
        //

        if (((NodeType(Fcb) == FAT_NTC_FCB) &&
             (Fcb->OpenCount == 0))

                ||

             ((NodeType(Fcb) == FAT_NTC_DCB) &&
              (IsListEmpty(&Fcb->Specific.Dcb.ParentDcbQueue)) &&
              (Fcb->OpenCount == 0) &&
              (Fcb->Specific.Dcb.DirectoryFileOpenCount == 0))) {

            ParentDcb = Fcb->ParentDcb;

            SetFlag( Vcb->VcbState, VCB_STATE_FLAG_DELETED_FCB );

            FatDeleteFcb( &IrpContext, &Fcb );

            //
            //  Uninitialize our parent's cache map if we no longer need
            //  to use it.
            //

            while ((NodeType(ParentDcb) == FAT_NTC_DCB) &&
                   IsListEmpty(&ParentDcb->Specific.Dcb.ParentDcbQueue) &&
                   (ParentDcb->OpenCount == 0) &&
                   (ParentDcb->Specific.Dcb.DirectoryFile != NULL)) {

                PFILE_OBJECT DirectoryFileObject;

                DirectoryFileObject = ParentDcb->Specific.Dcb.DirectoryFile;

                DebugTrace(0, Dbg, "Uninitialize our parent Stream Cache Map\n", 0);

                CcUninitializeCacheMap( DirectoryFileObject, NULL, NULL );

                ParentDcb->Specific.Dcb.DirectoryFile = NULL;

                ObDereferenceObject( DirectoryFileObject );

                //
                //  Now, if the ObDereferenceObject() caused the final close
                //  to come in, then blow away the Fcb and continue up,
                //  otherwise wait for Mm to to dereference its file objects
                //  and stop here..
                //

                if ( ParentDcb->Specific.Dcb.DirectoryFileOpenCount == 0) {

                    PDCB CurrentDcb;

                    CurrentDcb = ParentDcb;
                    ParentDcb = CurrentDcb->ParentDcb;

                    SetFlag( Vcb->VcbState, VCB_STATE_FLAG_DELETED_FCB );

                    FatDeleteFcb( &IrpContext, &CurrentDcb );

                } else {

                    break;
                }
            }
        }

        Status = STATUS_SUCCESS;

    try_exit: NOTHING;
    } finally {

        DebugUnwind( FatCommonClose );

        //
        //  We are done processing the close.  If we are the top of the close
        //  chain, see if the VCB can go away.  We have biased the open count by
        //  one, so we need to take that into account.
        //

        if (!RecursiveClose) {

            //
            //  See if there is only one open left.  If so, it is ours.  We only want
            //  to check for a dismount if a dismount is not already in progress.
            //  We also only do this if the caller can handle the VCB going away.
            //  This is determined by whether they passed in the VcbDeleted argument.
            //

            if (Vcb->OpenFileCount == 1 &&
                !FlagOn( Vcb->VcbState, VCB_STATE_FLAG_DISMOUNT_IN_PROGRESS )
                && ARGUMENT_PRESENT( VcbDeleted )) {

                //
                //  We need the global lock, which must be acquired before the
                //  VCB.  Since we already have the VCB, we have to drop and
                //  reaquire here.  Note that we always want to wait from this
                //  point on.  Note that the VCB cannot go away, since we have
                //  biased the open file count.
                //

                FatReleaseVcb( &IrpContext,
                               Vcb );

                SetFlag( IrpContext.Flags, IRP_CONTEXT_FLAG_WAIT );

                FatAcquireExclusiveGlobal( &IrpContext );

                FatAcquireExclusiveVcb( &IrpContext,
                                        Vcb );

                //
                //  We have our locks in the correct order.  Remove our
                //  extra open and check for a dismount.  Note that if
                //  something changed while we dropped the lock, it will
                //  not matter, since the dismount code does the correct
                //  checks to make sure the volume can really go away.
                //

                Vcb->OpenFileCount -= 1;

                LocalVcbDeleted = FatCheckForDismount( &IrpContext,
                                                       Vcb,
                                                       FALSE );

                FatReleaseGlobal( &IrpContext );

                //
                //  Let the caller know what happened, if they want this information.
                //

                if (ARGUMENT_PRESENT( VcbDeleted )) {

                    *VcbDeleted = LocalVcbDeleted;
                }

            } else {

                //
                //  The volume cannot go away now.  Just remove our extra reference.
                //

                Vcb->OpenFileCount -= 1;
            }

            //
            //  If the VCB is still around, clear our recursion flag.
            //

            if (!LocalVcbDeleted) {

                ClearFlag( Vcb->VcbState, VCB_STATE_FLAG_CLOSE_IN_PROGRESS );
            }
        }

        //
        //  Only release the VCB if it did not go away.
        //

        if (!LocalVcbDeleted) {

            FatReleaseVcb( &IrpContext, Vcb );
        }

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

    return Status;
}