Exemplo n.º 1
0
NTSTATUS
FFSWriteFile(
	IN PFFS_IRP_CONTEXT IrpContext)
{
	NTSTATUS            Status = STATUS_UNSUCCESSFUL;

	PFFS_VCB            Vcb  = NULL;
	PFFS_FCB            Fcb  = NULL;
	PFFS_CCB            Ccb =  NULL;
	PFILE_OBJECT        FileObject  = NULL;
	PFILE_OBJECT        CacheObject;

	PDEVICE_OBJECT      DeviceObject  = NULL;

	PIRP                Irp  = NULL;
	PIO_STACK_LOCATION  IoStackLocation  = NULL;

	ULONG               Length;
	ULONG               ReturnedLength = 0;
	LARGE_INTEGER       ByteOffset;

	BOOLEAN             PagingIo;
	BOOLEAN             Nocache;
	BOOLEAN             SynchronousIo;
	BOOLEAN             MainResourceAcquired = FALSE;
	BOOLEAN             PagingIoResourceAcquired = FALSE;

	BOOLEAN             bNeedExtending = FALSE;
	BOOLEAN             bAppendFile = FALSE;

	BOOLEAN             bDeferred = FALSE;

	PUCHAR              Buffer = NULL;

	__try
	{
		ASSERT(IrpContext);

		ASSERT((IrpContext->Identifier.Type == FFSICX) &&
				(IrpContext->Identifier.Size == sizeof(FFS_IRP_CONTEXT)));

		DeviceObject = IrpContext->DeviceObject;

		Vcb = (PFFS_VCB)DeviceObject->DeviceExtension;

		ASSERT(Vcb != NULL);

		ASSERT((Vcb->Identifier.Type == FFSVCB) &&
				(Vcb->Identifier.Size == sizeof(FFS_VCB)));

		FileObject = IrpContext->FileObject;

		Fcb = (PFFS_FCB)FileObject->FsContext;

		ASSERT(Fcb);

		ASSERT((Fcb->Identifier.Type == FFSFCB) &&
				(Fcb->Identifier.Size == sizeof(FFS_FCB)));

		Ccb = (PFFS_CCB)FileObject->FsContext2;

		Irp = IrpContext->Irp;

		IoStackLocation = IoGetCurrentIrpStackLocation(Irp);

		Length = IoStackLocation->Parameters.Write.Length;
		ByteOffset = IoStackLocation->Parameters.Write.ByteOffset;

		PagingIo = (Irp->Flags & IRP_PAGING_IO ? TRUE : FALSE);
		Nocache = (Irp->Flags & IRP_NOCACHE ? TRUE : FALSE);
		SynchronousIo = (FileObject->Flags & FO_SYNCHRONOUS_IO ? TRUE : FALSE);

		FFSPrint((DBG_INFO, "FFSWriteFile: Off=%I64xh Len=%xh Paging=%xh Nocache=%xh\n",
					ByteOffset.QuadPart, Length, PagingIo, Nocache));

		/*
		if (IsFlagOn(Fcb->Flags, FCB_FILE_DELETED))
		{
			Status = STATUS_FILE_DELETED;
			__leave;
		}

		if (IsFlagOn(Fcb->Flags, FCB_DELETE_PENDING))
		{
			Status = STATUS_DELETE_PENDING;
			__leave;
		}
		*/

		if (Length == 0)
		{
			Irp->IoStatus.Information = 0;
			Status = STATUS_SUCCESS;
			__leave;
		}

		if (Nocache &&
				(ByteOffset.LowPart & (SECTOR_SIZE - 1) ||
				 Length & (SECTOR_SIZE - 1)))
		{
			Status = STATUS_INVALID_PARAMETER;
			__leave;
		}

		if (FlagOn(IrpContext->MinorFunction, IRP_MN_DPC))
		{
			ClearFlag(IrpContext->MinorFunction, IRP_MN_DPC);
			Status = STATUS_PENDING;
			__leave;
		}

#if FALSE
		if (!Nocache)
		{
			BOOLEAN bAgain = IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_DEFERRED);
			BOOLEAN bWait  = IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);
			BOOLEAN bQueue = IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_REQUEUED);

			if (!CcCanIWrite(
						FileObject,
						Length,
						(bWait && bQueue),
						bAgain))
			{
				SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_DEFERRED);

				CcDeferWrite(FileObject,
						(PCC_POST_DEFERRED_WRITE)FFSDeferWrite,
						IrpContext,
						Irp,
						Length,
						bAgain);

				bDeferred = TRUE;

				FFSBreakPoint();

				Status = STATUS_PENDING;
				__leave;
			}
		}

#endif

		if (IsEndOfFile(ByteOffset))
		{
			bAppendFile = TRUE;
			ByteOffset.QuadPart = Fcb->Header.FileSize.QuadPart;
		}

		if (FlagOn(Fcb->FFSMcb->FileAttr, FILE_ATTRIBUTE_DIRECTORY) && !PagingIo)
		{
			Status = STATUS_INVALID_DEVICE_REQUEST;
			__leave;
		}

		//
		//  Do flushing for such cases
		//
		if (Nocache && !PagingIo && (Fcb->SectionObject.DataSectionObject != NULL)) 
		{
			ExAcquireResourceExclusive(&Fcb->MainResource, 
					IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT));

			MainResourceAcquired = TRUE;

			ExAcquireSharedStarveExclusive(&Fcb->PagingIoResource, TRUE);
			ExReleaseResource(&Fcb->PagingIoResource);

			CcFlushCache(&(Fcb->SectionObject),
					&ByteOffset,
					Length,
					&(Irp->IoStatus));
			ClearFlag(Fcb->Flags, FCB_FILE_MODIFIED);

			if (!NT_SUCCESS(Irp->IoStatus.Status)) 
			{
				Status = Irp->IoStatus.Status;
				__leave;
			}

			ExAcquireSharedStarveExclusive(&Fcb->PagingIoResource, TRUE);
			ExReleaseResource(&Fcb->PagingIoResource);

			CcPurgeCacheSection(&(Fcb->SectionObject),
					(PLARGE_INTEGER)&(ByteOffset),
					Length,
					FALSE);

			ExReleaseResource(&Fcb->MainResource);
			MainResourceAcquired = FALSE;
		}

		if (!PagingIo)
		{
			if (!ExAcquireResourceExclusiveLite(
						&Fcb->MainResource,
						IrpContext->IsSynchronous))
			{
				Status = STATUS_PENDING;
				__leave;
			}

			MainResourceAcquired = TRUE;
		}
		else
		{
			/*
			ULONG ResShCnt, ResExCnt; 
			ResShCnt = ExIsResourceAcquiredSharedLite(&Fcb->PagingIoResource);
			ResExCnt = ExIsResourceAcquiredExclusiveLite(&Fcb->PagingIoResource);

			FFSPrint((DBG_USER, "FFSWriteFile: Inode=%xh %S PagingIo: %xh:%xh Synchronous=%xh\n",
			Fcb->FFSMcb->Inode, Fcb->FFSMcb->ShortName.Buffer, ResShCnt, ResExCnt, IrpContext->IsSynchronous));
			*/
			if (!ExAcquireResourceSharedLite(
						&Fcb->PagingIoResource,
						IrpContext->IsSynchronous))
			{
				Status = STATUS_PENDING;
				__leave;
			}

			PagingIoResourceAcquired = TRUE;
		}

		if (!PagingIo)
		{
			if (!FsRtlCheckLockForWriteAccess(
						&Fcb->FileLockAnchor,
						Irp))
			{
				Status = STATUS_FILE_LOCK_CONFLICT;
				__leave;
			}
		}

		if (Nocache)
		{
			if ((ByteOffset.QuadPart + Length) >
					Fcb->Header.AllocationSize.QuadPart)
			{
				if (ByteOffset.QuadPart >= 
						Fcb->Header.AllocationSize.QuadPart)
				{
					Status = STATUS_SUCCESS;
					Irp->IoStatus.Information = 0;
					__leave;
				}
				else
				{
					if (Length > (ULONG)(Fcb->Header.AllocationSize.QuadPart
								- ByteOffset.QuadPart))
					{
						Length = (ULONG)(Fcb->Header.AllocationSize.QuadPart
								- ByteOffset.QuadPart);
					}
				}
			}
		}

		if (!Nocache)
		{
			if (FlagOn(Fcb->FFSMcb->FileAttr, FILE_ATTRIBUTE_DIRECTORY))
			{
				__leave;
			}

			if (FileObject->PrivateCacheMap == NULL)
			{
				CcInitializeCacheMap(
						FileObject,
						(PCC_FILE_SIZES)(&Fcb->Header.AllocationSize),
						FALSE,
						&FFSGlobal->CacheManagerCallbacks,
						Fcb);

				CcSetReadAheadGranularity(
						FileObject,
						READ_AHEAD_GRANULARITY);

				CcSetFileSizes(
						FileObject, 
						(PCC_FILE_SIZES)(&(Fcb->Header.AllocationSize)));
			}

			CacheObject = FileObject;

			//
			//  Need extending the size of inode ?
			//
			if ((bAppendFile) || ((ULONG)(ByteOffset.QuadPart + Length) >
						(ULONG)(Fcb->Header.FileSize.QuadPart)))
			{

				LARGE_INTEGER   ExtendSize;
				LARGE_INTEGER   FileSize;

				bNeedExtending = TRUE;
				FileSize = Fcb->Header.FileSize;
				ExtendSize.QuadPart = (LONGLONG)(ByteOffset.QuadPart + Length);

				if (ExtendSize.QuadPart > Fcb->Header.AllocationSize.QuadPart)
				{
					if (!FFSExpandFile(IrpContext, Vcb, Fcb, &ExtendSize))
					{
						Status = STATUS_INSUFFICIENT_RESOURCES;
						__leave;
					}
				}

				{
					Fcb->Header.FileSize.QuadPart = ExtendSize.QuadPart;
					Fcb->dinode1->di_size = (ULONG)ExtendSize.QuadPart;
				}

				if (FileObject->PrivateCacheMap)
				{
					CcSetFileSizes(FileObject, (PCC_FILE_SIZES)(&(Fcb->Header.AllocationSize)));

					if (ByteOffset.QuadPart > FileSize.QuadPart)
					{
						FFSZeroHoles(IrpContext, Vcb, FileObject, FileSize.QuadPart, 
								ByteOffset.QuadPart - FileSize.QuadPart);
					}

					if (Fcb->Header.AllocationSize.QuadPart > ExtendSize.QuadPart)
					{
						FFSZeroHoles(IrpContext, Vcb, FileObject, ExtendSize.QuadPart, 
								Fcb->Header.AllocationSize.QuadPart - ExtendSize.QuadPart);
					}
				}

				if (FFSv1SaveInode(IrpContext, Vcb, Fcb->FFSMcb->Inode, Fcb->dinode1))
				{
					Status = STATUS_SUCCESS;
				}

				FFSNotifyReportChange(
						IrpContext,
						Vcb,
						Fcb,
						FILE_NOTIFY_CHANGE_SIZE,
						FILE_ACTION_MODIFIED);
			}

			if (FlagOn(IrpContext->MinorFunction, IRP_MN_MDL))
			{
				CcPrepareMdlWrite(
						CacheObject,
						(&ByteOffset),
						Length,
						&Irp->MdlAddress,
						&Irp->IoStatus);

				Status = Irp->IoStatus.Status;
			}
			else
			{
				Buffer = FFSGetUserBuffer(Irp);

				if (Buffer == NULL)
				{
					FFSBreakPoint();
					Status = STATUS_INVALID_USER_BUFFER;
					__leave;
				}

				if (!CcCopyWrite(
							CacheObject,
							(PLARGE_INTEGER)&ByteOffset,
							Length,
							IrpContext->IsSynchronous,
							Buffer))
				{
					Status = STATUS_PENDING;
					__leave;
				}

				Status = Irp->IoStatus.Status;
			}

			if (NT_SUCCESS(Status))
			{
				Irp->IoStatus.Information = Length;

				if (IsFlagOn(Vcb->Flags, VCB_FLOPPY_DISK))
				{
					FFSPrint((DBG_USER, "FFSWriteFile is starting FlushingDpc...\n"));
					FFSStartFloppyFlushDpc(Vcb, Fcb, FileObject);
				}
			}
		}
		else
		{
			ReturnedLength = Length;

			Status = FFSLockUserBuffer(
					IrpContext->Irp,
					Length,
					IoReadAccess);

			if (!NT_SUCCESS(Status))
			{
				__leave;
			}

			Irp->IoStatus.Status = STATUS_SUCCESS;
			Irp->IoStatus.Information = Length;

			Status = 
				FFSv1WriteInode(
						IrpContext,
						Vcb,
						Fcb->dinode1,
						(ULONGLONG)(ByteOffset.QuadPart),
						NULL,
						Length,
						TRUE,
						&ReturnedLength);

			Irp = IrpContext->Irp;

		}
	}

	__finally
	{
		if (PagingIoResourceAcquired)
		{
			ExReleaseResourceForThreadLite(
					&Fcb->PagingIoResource,
					ExGetCurrentResourceThread());
		}

		if (MainResourceAcquired)
		{
			ExReleaseResourceForThreadLite(
					&Fcb->MainResource,
					ExGetCurrentResourceThread());
		}

		if (!IrpContext->ExceptionInProgress)
		{
			if (Irp)
			{
				if (Status == STATUS_PENDING)
				{
					if (!bDeferred)
					{
						Status = FFSLockUserBuffer(
									IrpContext->Irp,
									Length,
									IoReadAccess);

						if (NT_SUCCESS(Status))
						{
							Status = FFSQueueRequest(IrpContext);
						}
						else
						{
							FFSCompleteIrpContext(IrpContext, Status);
						}
					}
				}
				else
				{
					if (NT_SUCCESS(Status))
					{
						if (SynchronousIo && !PagingIo)
						{
							FileObject->CurrentByteOffset.QuadPart =
								ByteOffset.QuadPart + Irp->IoStatus.Information;
						}

						if (!PagingIo)
						{
							SetFlag(FileObject->Flags, FO_FILE_MODIFIED);
							SetFlag(Fcb->Flags, FCB_FILE_MODIFIED);
						}
					}

					FFSCompleteIrpContext(IrpContext, Status);
				}
			}
			else
			{
				FFSFreeIrpContext(IrpContext);
			}
		}
	}

	return Status;

}
Exemplo n.º 2
0
NTSTATUS
Ext2WriteFile(IN PEXT2_IRP_CONTEXT IrpContext)
{
    PEXT2_VCB           Vcb = NULL;
    PEXT2_FCB           Fcb = NULL;
    PEXT2_CCB           Ccb = NULL;
    PFILE_OBJECT        FileObject = NULL;

    PDEVICE_OBJECT      DeviceObject = NULL;

    PIRP                Irp = NULL;
    PIO_STACK_LOCATION  IoStackLocation = NULL;
    PUCHAR              Buffer = NULL;

    LARGE_INTEGER       ByteOffset;
    ULONG               ReturnedLength = 0;
    ULONG               Length;

    NTSTATUS            Status = STATUS_UNSUCCESSFUL;

    BOOLEAN             OpPostIrp = FALSE;
    BOOLEAN             PagingIo = FALSE;
    BOOLEAN             Nocache = FALSE;
    BOOLEAN             SynchronousIo = FALSE;

    BOOLEAN             RecursiveWriteThrough = FALSE;
    BOOLEAN             MainResourceAcquired = FALSE;
    BOOLEAN             PagingIoResourceAcquired = FALSE;

    BOOLEAN             bDeferred = FALSE;
    BOOLEAN             UpdateFileValidSize = FALSE;
    BOOLEAN             FileSizesChanged = FALSE;
    BOOLEAN             rc;


    __try {

        ASSERT(IrpContext);
        ASSERT((IrpContext->Identifier.Type == EXT2ICX) &&
               (IrpContext->Identifier.Size == sizeof(EXT2_IRP_CONTEXT)));

        DeviceObject = IrpContext->DeviceObject;
        Vcb = (PEXT2_VCB) DeviceObject->DeviceExtension;
        ASSERT(Vcb != NULL);
        ASSERT((Vcb->Identifier.Type == EXT2VCB) &&
               (Vcb->Identifier.Size == sizeof(EXT2_VCB)));

        FileObject = IrpContext->FileObject;
        Fcb = (PEXT2_FCB) FileObject->FsContext;
        Ccb = (PEXT2_CCB) FileObject->FsContext2;
        ASSERT(Fcb);
        ASSERT((Fcb->Identifier.Type == EXT2FCB) &&
               (Fcb->Identifier.Size == sizeof(EXT2_FCB)));

        Irp = IrpContext->Irp;
        IoStackLocation = IoGetCurrentIrpStackLocation(Irp);

        Length = IoStackLocation->Parameters.Write.Length;
        ByteOffset = IoStackLocation->Parameters.Write.ByteOffset;

        PagingIo = IsFlagOn(Irp->Flags, IRP_PAGING_IO);
        Nocache = IsFlagOn(Irp->Flags, IRP_NOCACHE);
        SynchronousIo = IsFlagOn(FileObject->Flags, FO_SYNCHRONOUS_IO);

        if (PagingIo) {
            ASSERT(Nocache);
        }

        DEBUG(DL_INF, ("Ext2WriteFile: %wZ Offset=%I64xh Length=%xh Paging=%xh Nocache=%xh\n",
                       &Fcb->Mcb->ShortName, ByteOffset.QuadPart, Length, PagingIo, Nocache));

        if (IsSpecialFile(Fcb) || IsInodeSymLink(Fcb->Inode) ) {
            Status = STATUS_INVALID_DEVICE_REQUEST;
            __leave;
        }

        if (IsFileDeleted(Fcb->Mcb) ||
            (IsSymLink(Fcb) && IsFileDeleted(Fcb->Mcb->Target)) ) {
            Status = STATUS_FILE_DELETED;
            __leave;
        }

        if (Length == 0) {
            Irp->IoStatus.Information = 0;
            Status = STATUS_SUCCESS;
            __leave;
        }

        if (ByteOffset.LowPart == FILE_USE_FILE_POINTER_POSITION &&
            ByteOffset.HighPart == -1) {
            ByteOffset = FileObject->CurrentByteOffset;
        } else if (IsWritingToEof(ByteOffset)) {
            ByteOffset.QuadPart = Fcb->Header.FileSize.QuadPart;
        }

        if (Nocache && !PagingIo &&
            ( (ByteOffset.LowPart & (SECTOR_SIZE - 1)) ||
               (Length & (SECTOR_SIZE - 1))) ) {
            Status = STATUS_INVALID_PARAMETER;
            __leave;
        }

        if (FlagOn(IrpContext->MinorFunction, IRP_MN_DPC)) {
            ClearFlag(IrpContext->MinorFunction, IRP_MN_DPC);
            Status = STATUS_PENDING;
            __leave;
        }

        if (!Nocache) {

            BOOLEAN bAgain = IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_DEFERRED);
            BOOLEAN bWait  = IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);
            BOOLEAN bQueue = IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_REQUEUED);

            if ( !CcCanIWrite(
                        FileObject,
                        Length,
                        (bWait && bQueue),
                        bAgain ) ) {

                Status = Ext2LockUserBuffer(
                             IrpContext->Irp,
                             Length,
                             IoReadAccess);

                if (NT_SUCCESS(Status)) {
                    SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_DEFERRED);
                    CcDeferWrite( FileObject,
                                  (PCC_POST_DEFERRED_WRITE)Ext2DeferWrite,
                                  IrpContext,
                                  Irp,
                                  Length,
                                  bAgain );
                    bDeferred = TRUE;
                    Status = STATUS_PENDING;
                    __leave;
                }
            }
        }

        if (IsDirectory(Fcb) && !PagingIo) {
            Status = STATUS_INVALID_DEVICE_REQUEST;
            __leave;
        }

        if (IsFlagOn(Irp->Flags, IRP_SYNCHRONOUS_PAGING_IO) && !IrpContext->IsTopLevel) {

            PIRP TopIrp;

            TopIrp = IoGetTopLevelIrp();

            if ( (ULONG_PTR)TopIrp > FSRTL_MAX_TOP_LEVEL_IRP_FLAG &&
                    NodeType(TopIrp) == IO_TYPE_IRP) {

                PIO_STACK_LOCATION IrpStack;

                IrpStack = IoGetCurrentIrpStackLocation(TopIrp);

                if ((IrpStack->MajorFunction == IRP_MJ_WRITE) &&
                    (IrpStack->FileObject->FsContext == FileObject->FsContext) &&
                    !FlagOn(TopIrp->Flags, IRP_NOCACHE) ) {

                    SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WRITE_THROUGH);
                    RecursiveWriteThrough = TRUE;
                }
            }
        }

        if (PagingIo) {

            if (!ExAcquireResourceSharedLite(&Fcb->PagingIoResource, TRUE)) {
                Status = STATUS_PENDING;
                __leave;
            }
            PagingIoResourceAcquired = TRUE;

            if ( (ByteOffset.QuadPart + Length) > Fcb->Header.FileSize.QuadPart) {

                if (ByteOffset.QuadPart >= Fcb->Header.AllocationSize.QuadPart) {

                    Status = STATUS_SUCCESS;
                    Irp->IoStatus.Information = 0;
                    __leave;

                } else {

                    ReturnedLength = (ULONG)(Fcb->Header.FileSize.QuadPart - ByteOffset.QuadPart);
                    if (ByteOffset.QuadPart + Length > Fcb->Header.AllocationSize.QuadPart)
                        Length = (ULONG)(Fcb->Header.AllocationSize.QuadPart - ByteOffset.QuadPart);
                }

            } else {

                ReturnedLength = Length;
            }

        } else {

            if (!Ext2CheckFileAccess(Vcb, Fcb->Mcb, Ext2FileCanWrite)) {
                Status = STATUS_ACCESS_DENIED;
                __leave;
            }

            if (IsDirectory(Fcb)) {
                __leave;
            }

            if (!ExAcquireResourceExclusiveLite(&Fcb->MainResource, TRUE)) {
                Status = STATUS_PENDING;
                __leave;
            }
            MainResourceAcquired = TRUE;

            //
            //  Do flushing for such cases
            //
            if (Nocache && Ccb != NULL && Fcb->SectionObject.DataSectionObject != NULL)  {

                ExAcquireSharedStarveExclusive( &Fcb->PagingIoResource, TRUE);
                ExReleaseResourceLite(&Fcb->PagingIoResource);

                CcFlushCache( &(Fcb->SectionObject),
                              &ByteOffset,
                              CEILING_ALIGNED(ULONG, Length, BLOCK_SIZE),
                              &(Irp->IoStatus));
                ClearLongFlag(Fcb->Flags, FCB_FILE_MODIFIED);

                if (!NT_SUCCESS(Irp->IoStatus.Status)) {
                    Status = Irp->IoStatus.Status;
                    __leave;
                }

                ExAcquireSharedStarveExclusive( &Fcb->PagingIoResource, TRUE);
                ExReleaseResourceLite(&Fcb->PagingIoResource);

                CcPurgeCacheSection( &(Fcb->SectionObject),
                                     &(ByteOffset),
                                     CEILING_ALIGNED(ULONG, Length, BLOCK_SIZE),
                                     FALSE );
            }

            if (!FsRtlCheckLockForWriteAccess(&Fcb->FileLockAnchor, Irp)) {
                Status = STATUS_FILE_LOCK_CONFLICT;
                __leave;
            }

            if (Ccb != NULL) {

                Status = FsRtlCheckOplock( &Fcb->Oplock,
                                           Irp,
                                           IrpContext,
                                           Ext2OplockComplete,
                                           Ext2LockIrp );

                if (Status != STATUS_SUCCESS) {
                    OpPostIrp = TRUE;
                    __leave;
                }

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

                Fcb->Header.IsFastIoPossible = Ext2IsFastIoPossible(Fcb);
            }

            //
            //  Extend the inode size when the i/o is beyond the file end ?
            //

            if ((ByteOffset.QuadPart + Length) > Fcb->Header.FileSize.QuadPart) {

                LARGE_INTEGER AllocationSize, Last;

                if (!ExAcquireResourceExclusiveLite(&Fcb->PagingIoResource, TRUE)) {
                    Status = STATUS_PENDING;
                    __leave;
                }
                PagingIoResourceAcquired = TRUE;

                /* let this irp wait, since it has to be synchronous */
                SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);

                Last.QuadPart = Fcb->Header.AllocationSize.QuadPart;
                AllocationSize.QuadPart = (LONGLONG)(ByteOffset.QuadPart + Length);
                AllocationSize.QuadPart = CEILING_ALIGNED(ULONGLONG,
                                          (ULONGLONG)AllocationSize.QuadPart,
                                          (ULONGLONG)BLOCK_SIZE);

                /* tell Ext2ExpandFile to allocate unwritten extent or NULL blocks
                   for indirect files, otherwise we might get gabage data in holes */
                IrpContext->MajorFunction += IRP_MJ_MAXIMUM_FUNCTION;
                Status = Ext2ExpandFile(IrpContext, Vcb, Fcb->Mcb, &AllocationSize);
                IrpContext->MajorFunction -= IRP_MJ_MAXIMUM_FUNCTION;
                if (AllocationSize.QuadPart > Last.QuadPart) {
                    Fcb->Header.AllocationSize.QuadPart = AllocationSize.QuadPart;
                    SetLongFlag(Fcb->Flags, FCB_ALLOC_IN_WRITE);
                }
                ExReleaseResourceLite(&Fcb->PagingIoResource);
                PagingIoResourceAcquired = FALSE;

                if (ByteOffset.QuadPart >= Fcb->Header.AllocationSize.QuadPart) {
                    if (NT_SUCCESS(Status)) {
                        DbgBreak();
                        Status = STATUS_UNSUCCESSFUL;
                    }
                    __leave;
                }

                if (ByteOffset.QuadPart + Length > Fcb->Header.AllocationSize.QuadPart) {
                    Length = (ULONG)(Fcb->Header.AllocationSize.QuadPart - ByteOffset.QuadPart);
                }

                Fcb->Header.FileSize.QuadPart = Fcb->Inode->i_size = ByteOffset.QuadPart + Length;
                Ext2SaveInode(IrpContext, Vcb, Fcb->Inode);

                if (CcIsFileCached(FileObject)) {
                    CcSetFileSizes(FileObject, (PCC_FILE_SIZES)(&(Fcb->Header.AllocationSize)));
                }

                FileObject->Flags |= FO_FILE_SIZE_CHANGED | FO_FILE_MODIFIED;
                FileSizesChanged = TRUE;

                if (Fcb->Header.FileSize.QuadPart >= 0x80000000 &&
                        !IsFlagOn(SUPER_BLOCK->s_feature_ro_compat, EXT2_FEATURE_RO_COMPAT_LARGE_FILE)) {
                    SetFlag(SUPER_BLOCK->s_feature_ro_compat, EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
                    Ext2SaveSuper(IrpContext, Vcb);
                }

                DEBUG(DL_IO, ("Ext2WriteFile: expanding %wZ to FS: %I64xh FA: %I64xh\n",
                              &Fcb->Mcb->ShortName, Fcb->Header.FileSize.QuadPart,
                              Fcb->Header.AllocationSize.QuadPart));
            }

            ReturnedLength = Length;
        }

        if (!Nocache) {

            if (FileObject->PrivateCacheMap == NULL) {
                CcInitializeCacheMap(
                    FileObject,
                    (PCC_FILE_SIZES)(&Fcb->Header.AllocationSize),
                    FALSE,
                    &Ext2Global->CacheManagerCallbacks,
                    Fcb );

                CcSetReadAheadGranularity(
                    FileObject,
                    READ_AHEAD_GRANULARITY );
            }

            if (FlagOn(IrpContext->MinorFunction, IRP_MN_MDL)) {

                CcPrepareMdlWrite(
                    FileObject,
                    &ByteOffset,
                    Length,
                    &Irp->MdlAddress,
                    &Irp->IoStatus );

                Status = Irp->IoStatus.Status;

            } else {

                Buffer = Ext2GetUserBuffer(Irp);
                if (Buffer == NULL) {
                    DbgBreak();
                    Status = STATUS_INVALID_USER_BUFFER;
                    __leave;
                }

                if (ByteOffset.QuadPart > Fcb->Header.ValidDataLength.QuadPart) {

                    /* let this irp wait, since it has to be synchronous */
                    SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);

                    rc = Ext2ZeroData(IrpContext, Vcb, FileObject,
                                      &Fcb->Header.ValidDataLength, &ByteOffset);
                    if (!rc) {
                        Status = STATUS_PENDING;
                        DbgBreak();
                        __leave;
                    }
                }

                if (!CcCopyWrite(FileObject, &ByteOffset, Length, Ext2CanIWait(), Buffer)) {
                    if (Ext2CanIWait() || 
                        !CcCopyWrite(FileObject,  &ByteOffset, Length, TRUE, Buffer)) {
                        Status = STATUS_PENDING;
                        DbgBreak();
                        __leave;
                    }
                }

                if (ByteOffset.QuadPart + Length > Fcb->Header.ValidDataLength.QuadPart ) {

                    if (Fcb->Header.FileSize.QuadPart < ByteOffset.QuadPart + Length) {
                        Fcb->Header.ValidDataLength.QuadPart = Fcb->Header.FileSize.QuadPart;
                    } else {
                        if (Fcb->Header.ValidDataLength.QuadPart < ByteOffset.QuadPart + Length)
                            Fcb->Header.ValidDataLength.QuadPart = ByteOffset.QuadPart + Length;
                    }

                    CcSetFileSizes(FileObject, (PCC_FILE_SIZES)(&(Fcb->Header.AllocationSize)));
                    FileSizesChanged = TRUE;
                }

                Status = STATUS_SUCCESS;
            }

            if (NT_SUCCESS(Status)) {
                Irp->IoStatus.Information = Length;
                if (IsFlagOn(Vcb->Flags, VCB_FLOPPY_DISK)) {
                    DEBUG(DL_FLP, ("Ext2WriteFile is starting FlushingDpc...\n"));
                    Ext2StartFloppyFlushDpc(Vcb, Fcb, FileObject);
                }
            }

        } else {

            if (!PagingIo && !RecursiveWriteThrough && !IsLazyWriter(Fcb)) {
                if (ByteOffset.QuadPart > Fcb->Header.ValidDataLength.QuadPart) {

                    /* let this irp wait, since it has to be synchronous */
                    SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT);
                    rc = Ext2ZeroData(IrpContext, Vcb, FileObject,
                                      &Fcb->Header.ValidDataLength,
                                      &ByteOffset);
                    if (!rc) {
                        Status = STATUS_PENDING;
                        DbgBreak();
                        __leave;
                    }
                }
            }

            Status = Ext2LockUserBuffer(
                         IrpContext->Irp,
                         Length,
                         IoReadAccess );

            if (!NT_SUCCESS(Status)) {
                __leave;
            }

            Irp->IoStatus.Status = STATUS_SUCCESS;
            Irp->IoStatus.Information = ReturnedLength;

            Status = Ext2WriteInode(
                         IrpContext,
                         Vcb,
                         Fcb->Mcb,
                         (ULONGLONG)(ByteOffset.QuadPart),
                         NULL,
                         ReturnedLength,
                         TRUE,
                         &Length
                     );

            Irp = IrpContext->Irp;

            if (NT_SUCCESS(Status) && !RecursiveWriteThrough && !IsLazyWriter(Fcb)) {

                if (ByteOffset.QuadPart + Length > Fcb->Header.ValidDataLength.QuadPart ) {

                    FileSizesChanged = TRUE;

                    if (Fcb->Header.FileSize.QuadPart < ByteOffset.QuadPart + Length) {
                        if (!PagingIo)
                            Fcb->Header.FileSize.QuadPart = ByteOffset.QuadPart + Length;
                        Fcb->Header.ValidDataLength.QuadPart = Fcb->Header.FileSize.QuadPart;
                    } else {
                        if (Fcb->Header.ValidDataLength.QuadPart < ByteOffset.QuadPart + Length)
                            Fcb->Header.ValidDataLength.QuadPart = ByteOffset.QuadPart + Length;
                    }

                    if (!PagingIo && CcIsFileCached(FileObject)) {
                        CcSetFileSizes(FileObject, (PCC_FILE_SIZES)(&(Fcb->Header.AllocationSize)));
                    }

                    DEBUG(DL_IO, ("Ext2WriteFile: %wZ written FS: %I64xh FA: %I64xh BO: %I64xh LEN: %u\n",
                                  &Fcb->Mcb->ShortName, Fcb->Header.FileSize.QuadPart,
                                   Fcb->Header.AllocationSize.QuadPart, ByteOffset.QuadPart, Length));
                }
            }
        }

        if (FileSizesChanged) {
            FileObject->Flags |= FO_FILE_SIZE_CHANGED | FO_FILE_MODIFIED;
            Ext2NotifyReportChange( IrpContext,  Vcb, Fcb->Mcb,
                                    FILE_NOTIFY_CHANGE_SIZE,
                                    FILE_ACTION_MODIFIED );
        }

    } __finally {

        /*
         *  in case we got excpetions, we need revert MajorFunction
         *  back to IRP_MJ_WRITE. The reason we do this, is to tell
         *  Ext2ExpandFile to allocate unwritten extent or don't add
         *  new blocks for indirect files.
         */
        if (IrpContext->MajorFunction > IRP_MJ_MAXIMUM_FUNCTION)
            IrpContext->MajorFunction -= IRP_MJ_MAXIMUM_FUNCTION;

        if (Irp) {
            if (PagingIoResourceAcquired) {
                ExReleaseResourceLite(&Fcb->PagingIoResource);
            }

            if (MainResourceAcquired) {
                ExReleaseResourceLite(&Fcb->MainResource);
            }
        }

        if (!OpPostIrp && !IrpContext->ExceptionInProgress) {

            if (Irp) {

                if (Status == STATUS_PENDING ||
                        Status == STATUS_CANT_WAIT ) {

                    if (!bDeferred) {
                        Status = Ext2QueueRequest(IrpContext);
                    }

                } else {

                    if (NT_SUCCESS(Status) && !PagingIo) {

                        if (SynchronousIo) {
                            FileObject->CurrentByteOffset.QuadPart =
                                ByteOffset.QuadPart + Irp->IoStatus.Information;
                        }

                        SetFlag(FileObject->Flags, FO_FILE_MODIFIED);
                        SetLongFlag(Fcb->Flags, FCB_FILE_MODIFIED);
                    }

                    Ext2CompleteIrpContext(IrpContext, Status);
                }
            } else {
                Ext2FreeIrpContext(IrpContext);
            }
        }
    }

    DEBUG(DL_IO, ("Ext2WriteFile: %wZ written at Offset=%I64xh Length=%xh PagingIo=%d Nocache=%d "
                  "RetLen=%xh VDL=%I64xh FileSize=%I64xh i_size=%I64xh Status=%xh\n",
                  &Fcb->Mcb->ShortName, ByteOffset, Length, PagingIo, Nocache, ReturnedLength,
                  Fcb->Header.ValidDataLength.QuadPart,Fcb->Header.FileSize.QuadPart,
                  Fcb->Inode->i_size, Status));

    return Status;
}
Exemplo n.º 3
0
Arquivo: read.c Projeto: jrfl/ext2fsd
NTSTATUS
Ext2ReadFile(IN PEXT2_IRP_CONTEXT IrpContext)
{
    NTSTATUS            Status = STATUS_UNSUCCESSFUL;

    PEXT2_VCB           Vcb = NULL;
    PEXT2_FCB           Fcb = NULL;
    PEXT2_CCB           Ccb = NULL;
    PFILE_OBJECT        FileObject = NULL;

    PDEVICE_OBJECT      DeviceObject = NULL;

    PIRP                Irp = NULL;
    PIO_STACK_LOCATION  IoStackLocation = NULL;

    ULONG               Length;
    ULONG               ReturnedLength = 0;
    LARGE_INTEGER       ByteOffset;

    BOOLEAN             OpPostIrp = FALSE;
    BOOLEAN             PagingIo;
    BOOLEAN             Nocache;
    BOOLEAN             SynchronousIo;
    BOOLEAN             MainResourceAcquired = FALSE;
    BOOLEAN             PagingIoResourceAcquired = FALSE;

    PUCHAR              Buffer;

    __try {

        ASSERT(IrpContext);
        ASSERT((IrpContext->Identifier.Type == EXT2ICX) &&
               (IrpContext->Identifier.Size == sizeof(EXT2_IRP_CONTEXT)));

        DeviceObject = IrpContext->DeviceObject;
        Vcb = (PEXT2_VCB) DeviceObject->DeviceExtension;
        ASSERT(Vcb != NULL);
        ASSERT((Vcb->Identifier.Type == EXT2VCB) &&
               (Vcb->Identifier.Size == sizeof(EXT2_VCB)));

        FileObject = IrpContext->FileObject;
        Fcb = (PEXT2_FCB) FileObject->FsContext;
        ASSERT(Fcb);
        ASSERT((Fcb->Identifier.Type == EXT2FCB) &&
               (Fcb->Identifier.Size == sizeof(EXT2_FCB)));

        Ccb = (PEXT2_CCB) FileObject->FsContext2;

        Irp = IrpContext->Irp;
        IoStackLocation = IoGetCurrentIrpStackLocation(Irp);

        Length = IoStackLocation->Parameters.Read.Length;
        ByteOffset = IoStackLocation->Parameters.Read.ByteOffset;

        PagingIo = IsFlagOn(Irp->Flags, IRP_PAGING_IO);
        Nocache = IsFlagOn(Irp->Flags, IRP_NOCACHE);
        SynchronousIo = IsFlagOn(FileObject->Flags, FO_SYNCHRONOUS_IO);

        if (PagingIo) {
            ASSERT(Nocache);
        }

        DEBUG(DL_INF, ("Ext2ReadFile: reading %wZ Off=%I64xh Len=%xh Paging=%xh Nocache=%xh\n",
                       &Fcb->Mcb->ShortName, ByteOffset.QuadPart, Length, PagingIo, Nocache));

        if ((IsSymLink(Fcb) && IsFileDeleted(Fcb->Mcb->Target)) ||
            IsFileDeleted(Fcb->Mcb)) {
            Status = STATUS_FILE_DELETED;
            __leave;
        }

        if (Length == 0) {
            Irp->IoStatus.Information = 0;
            Status = STATUS_SUCCESS;
            __leave;
        }

        if (Nocache &&
                (ByteOffset.LowPart & (SECTOR_SIZE - 1) ||
                 Length & (SECTOR_SIZE - 1))) {
            Status = STATUS_INVALID_PARAMETER;
            DbgBreak();
            __leave;
        }

        if (FlagOn(IrpContext->MinorFunction, IRP_MN_DPC)) {
            ClearFlag(IrpContext->MinorFunction, IRP_MN_DPC);
            Status = STATUS_PENDING;
            DbgBreak();
            __leave;
        }

        if (!PagingIo && Nocache && (FileObject->SectionObjectPointer->DataSectionObject != NULL)) {
            CcFlushCache( FileObject->SectionObjectPointer,
                          &ByteOffset,
                          Length,
                          &Irp->IoStatus );

            if (!NT_SUCCESS(Irp->IoStatus.Status)) {
                __leave;
            }
        }

        ReturnedLength = Length;

        if (PagingIo) {

            if (!ExAcquireResourceSharedLite(
                        &Fcb->PagingIoResource,
                        IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT) )) {
                Status = STATUS_PENDING;
                __leave;
            }
            PagingIoResourceAcquired = TRUE;

        } else {

            if (Nocache) {

                if (!ExAcquireResourceExclusiveLite(
                            &Fcb->MainResource,
                            IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT) )) {
                    Status = STATUS_PENDING;
                    __leave;
                }
                MainResourceAcquired = TRUE;

            } else {

                if (!ExAcquireResourceSharedLite(
                            &Fcb->MainResource,
                            IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT) )) {
                    Status = STATUS_PENDING;
                    __leave;
                }
                MainResourceAcquired = TRUE;
            }

            if (!FsRtlCheckLockForReadAccess(
                        &Fcb->FileLockAnchor,
                        Irp         )) {
                Status = STATUS_FILE_LOCK_CONFLICT;
                __leave;
            }
        }

        if ((ByteOffset.QuadPart + (LONGLONG)Length) > Fcb->Header.FileSize.QuadPart) {
            if (ByteOffset.QuadPart >= Fcb->Header.FileSize.QuadPart) {
                Irp->IoStatus.Information = 0;
                Status = STATUS_END_OF_FILE;
                __leave;
            }
            ReturnedLength = (ULONG)(Fcb->Header.FileSize.QuadPart - ByteOffset.QuadPart);
        }


        if (!IsDirectory(Fcb) && Ccb != NULL) {

            Status = FsRtlCheckOplock( &Fcb->Oplock,
                                       Irp,
                                       IrpContext,
                                       Ext2OplockComplete,
                                       Ext2LockIrp );

            if (Status != STATUS_SUCCESS) {
                OpPostIrp = TRUE;
                __leave;
            }

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

            Fcb->Header.IsFastIoPossible = Ext2IsFastIoPossible(Fcb);
        }

        if (!Nocache) {

            if (IsDirectory(Fcb)) {
                __leave;
            }

            if (FileObject->PrivateCacheMap == NULL) {
                CcInitializeCacheMap(
                        FileObject,
                        (PCC_FILE_SIZES)(&Fcb->Header.AllocationSize),
                        FALSE,
                        &Ext2Global->CacheManagerCallbacks,
                        Fcb );
                CcSetReadAheadGranularity(
                        FileObject,
                        READ_AHEAD_GRANULARITY );
            }

            if (FlagOn(IrpContext->MinorFunction, IRP_MN_MDL)) {
                CcMdlRead(
                    FileObject,
                    (&ByteOffset),
                    ReturnedLength,
                    &Irp->MdlAddress,
                    &Irp->IoStatus );

                Status = Irp->IoStatus.Status;

            } else {

                Buffer = Ext2GetUserBuffer(Irp);
                if (Buffer == NULL) {
                    Status = STATUS_INVALID_USER_BUFFER;
                    DbgBreak();
                    __leave;
                }

                if (!CcCopyRead(FileObject, &ByteOffset, ReturnedLength,
                                Ext2CanIWait(), Buffer, &Irp->IoStatus)) {

                    if (Ext2CanIWait() || !CcCopyRead(FileObject, &ByteOffset,
                                                      ReturnedLength, TRUE,
                                                      Buffer, &Irp->IoStatus)) {
                        Status = STATUS_PENDING;
                        DbgBreak();
                        __leave;
                    }
                }
                Status = Irp->IoStatus.Status;
            }

        } else {

            ULONG   BytesRead = ReturnedLength;
            PUCHAR  SystemVA  = Ext2GetUserBuffer(IrpContext->Irp);

            if (ByteOffset.QuadPart + BytesRead > Fcb->Header.ValidDataLength.QuadPart) {

                if (ByteOffset.QuadPart >= Fcb->Header.ValidDataLength.QuadPart) {
                    if (SystemVA) {
                        SafeZeroMemory(SystemVA, Length);
                    }
                    Irp->IoStatus.Information = ReturnedLength;
                    Status = STATUS_SUCCESS;
                    __leave;
                } else {
                    BytesRead = (ULONG)(Fcb->Header.ValidDataLength.QuadPart - ByteOffset.QuadPart);
                    if (SystemVA) {
                        SafeZeroMemory(SystemVA + BytesRead, Length - BytesRead);
                    }
                }
            }

            Status = Ext2LockUserBuffer(
                         IrpContext->Irp,
                         BytesRead,
                         IoReadAccess );

            if (!NT_SUCCESS(Status)) {
                __leave;
            }

            Status = Ext2ReadInode(
                         IrpContext,
                         Vcb,
                         Fcb->Mcb,
                         ByteOffset.QuadPart,
                         NULL,
                         BytesRead,
                         TRUE,
                         NULL );

            /* we need re-queue this request in case STATUS_CANT_WAIT
               and fail it in other failure cases  */
            if (!NT_SUCCESS(Status)) {
                __leave;
            }

            /* pended by low level device */
            if (Status == STATUS_PENDING) {
                IrpContext->Irp = Irp = NULL;
                __leave;
            }

            Irp = IrpContext->Irp;
            ASSERT(Irp);
            Status = Irp->IoStatus.Status;

            if (!NT_SUCCESS(Status)) {
                Ext2NormalizeAndRaiseStatus(IrpContext, Status);
            }
        }

        Irp->IoStatus.Information = ReturnedLength;

    } __finally {

        if (Irp) {
            if (PagingIoResourceAcquired) {
                ExReleaseResourceLite(&Fcb->PagingIoResource);
            }

            if (MainResourceAcquired) {
                ExReleaseResourceLite(&Fcb->MainResource);
            }
        }

        if (!OpPostIrp && !IrpContext->ExceptionInProgress) {

            if (Irp) {
                if ( Status == STATUS_PENDING ||
                     Status == STATUS_CANT_WAIT) {

                    Status = Ext2LockUserBuffer(
                                 IrpContext->Irp,
                                 Length,
                                 IoWriteAccess );

                    if (NT_SUCCESS(Status)) {
                        Status = Ext2QueueRequest(IrpContext);
                    } else {
                        Ext2CompleteIrpContext(IrpContext, Status);
                    }
                } else {
                    if (NT_SUCCESS(Status)) {
                        if (!PagingIo) {
                            if (SynchronousIo) {
                                FileObject->CurrentByteOffset.QuadPart =
                                    ByteOffset.QuadPart + Irp->IoStatus.Information;
                            }
                            FileObject->Flags |= FO_FILE_FAST_IO_READ;
                        }
                    }

                    Ext2CompleteIrpContext(IrpContext, Status);
                }

            } else {

                Ext2FreeIrpContext(IrpContext);
            }
        }
    }

    DEBUG(DL_IO, ("Ext2ReadFile: %wZ fetch at Off=%I64xh Len=%xh Paging=%xh Nocache=%xh Returned=%xh Status=%xh\n",
                  &Fcb->Mcb->ShortName, ByteOffset.QuadPart, Length, PagingIo, Nocache, ReturnedLength, Status));
    return Status;

}
Exemplo n.º 4
0
Arquivo: read.c Projeto: GYGit/reactos
NTSTATUS STDCALL drv_read(PDEVICE_OBJECT DeviceObject, PIRP Irp) {
    PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);
    UINT8* data;
    PFILE_OBJECT FileObject = IrpSp->FileObject;
    fcb* fcb = FileObject->FsContext;
    UINT64 start;
    ULONG length, bytes_read;
    NTSTATUS Status;
    BOOL top_level;
    
    FsRtlEnterFileSystem();
    
    top_level = is_top_level(Irp);
    
    TRACE("read\n");
    
    Irp->IoStatus.Information = 0;
    
    if (IrpSp->MinorFunction & IRP_MN_COMPLETE) {
        CcMdlReadComplete(IrpSp->FileObject, Irp->MdlAddress);
        
        Irp->MdlAddress = NULL;
        Status = STATUS_SUCCESS;
        bytes_read = 0;
        
        goto exit;
    }
    
    start = IrpSp->Parameters.Read.ByteOffset.QuadPart;
    length = IrpSp->Parameters.Read.Length;
    bytes_read = 0;
    
    if (!fcb || !fcb->Vcb || !fcb->subvol) {
        Status = STATUS_INTERNAL_ERROR; // FIXME - invalid param error?
        goto exit;
    }
    
    TRACE("file = %S (fcb = %p)\n", file_desc(FileObject), fcb);
    TRACE("offset = %llx, length = %x\n", start, length);
    TRACE("paging_io = %s, no cache = %s\n", Irp->Flags & IRP_PAGING_IO ? "TRUE" : "FALSE", Irp->Flags & IRP_NOCACHE ? "TRUE" : "FALSE");

    if (fcb->type == BTRFS_TYPE_DIRECTORY) {
        Status = STATUS_INVALID_DEVICE_REQUEST;
        goto exit;
    }
    
    if (!(Irp->Flags & IRP_PAGING_IO) && !FsRtlCheckLockForReadAccess(&fcb->lock, Irp)) {
        WARN("tried to read locked region\n");
        Status = STATUS_FILE_LOCK_CONFLICT;
        goto exit;
    }
    
    if (length == 0) {
        WARN("tried to read zero bytes\n");
        Status = STATUS_SUCCESS;
        goto exit;
    }
    
    if (start >= fcb->Header.FileSize.QuadPart) {
        TRACE("tried to read with offset after file end (%llx >= %llx)\n", start, fcb->Header.FileSize.QuadPart);
        Status = STATUS_END_OF_FILE;
        goto exit;
    }
    
    TRACE("FileObject %p fcb %p FileSize = %llx st_size = %llx (%p)\n", FileObject, fcb, fcb->Header.FileSize.QuadPart, fcb->inode_item.st_size, &fcb->inode_item.st_size);
//     int3;
    
    if (Irp->Flags & IRP_NOCACHE || !(IrpSp->MinorFunction & IRP_MN_MDL)) {
        data = map_user_buffer(Irp);
        
        if (Irp->MdlAddress && !data) {
            ERR("MmGetSystemAddressForMdlSafe returned NULL\n");
            Status = STATUS_INSUFFICIENT_RESOURCES;
            goto exit;
        }
        
        if (length + start > fcb->Header.ValidDataLength.QuadPart) {
            RtlZeroMemory(data + (fcb->Header.ValidDataLength.QuadPart - start), length - (fcb->Header.ValidDataLength.QuadPart - start));
            length = fcb->Header.ValidDataLength.QuadPart - start;
        }
    }
        
    if (!(Irp->Flags & IRP_NOCACHE)) {
        BOOL wait;
        
        Status = STATUS_SUCCESS;
        
        _SEH2_TRY {
            if (!FileObject->PrivateCacheMap) {
                CC_FILE_SIZES ccfs;
                
                ccfs.AllocationSize = fcb->Header.AllocationSize;
                ccfs.FileSize = fcb->Header.FileSize;
                ccfs.ValidDataLength = fcb->Header.ValidDataLength;
                
                TRACE("calling CcInitializeCacheMap (%llx, %llx, %llx)\n",
                            ccfs.AllocationSize.QuadPart, ccfs.FileSize.QuadPart, ccfs.ValidDataLength.QuadPart);
                CcInitializeCacheMap(FileObject, &ccfs, FALSE, cache_callbacks, FileObject);

                CcSetReadAheadGranularity(FileObject, READ_AHEAD_GRANULARITY);
            }
            
            // FIXME - uncomment this when async is working
    //         wait = IoIsOperationSynchronous(Irp) ? TRUE : FALSE;
            wait = TRUE;
            
            if (IrpSp->MinorFunction & IRP_MN_MDL) {
                CcMdlRead(FileObject,&IrpSp->Parameters.Read.ByteOffset, length, &Irp->MdlAddress, &Irp->IoStatus);
            } else {
                TRACE("CcCopyRead(%p, %llx, %x, %u, %p, %p)\n", FileObject, IrpSp->Parameters.Read.ByteOffset.QuadPart, length, wait, data, &Irp->IoStatus);
                TRACE("sizes = %llx, %llx, %llx\n", fcb->Header.AllocationSize, fcb->Header.FileSize, fcb->Header.ValidDataLength);
                if (!CcCopyRead(FileObject, &IrpSp->Parameters.Read.ByteOffset, length, wait, data, &Irp->IoStatus)) {
                    TRACE("CcCopyRead failed\n");
                    
                    IoMarkIrpPending(Irp);
                    Status = STATUS_PENDING;
                    goto exit;
                }
                TRACE("CcCopyRead finished\n");
            }
        } _SEH2_EXCEPT (EXCEPTION_EXECUTE_HANDLER) {
            Status = _SEH2_GetExceptionCode();
        } _SEH2_END;
        
        if (NT_SUCCESS(Status)) {
            Status = Irp->IoStatus.Status;
            bytes_read = Irp->IoStatus.Information;
        } else
            ERR("EXCEPTION - %08x\n", Status);
    } else {