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/** @file
EFI_FILE_PROTOCOL.Write() member function for the Virtio Filesystem driver.
Copyright (C) 2020, Red Hat, Inc.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "VirtioFsDxe.h"
EFI_STATUS
EFIAPI
VirtioFsSimpleFileWrite (
IN EFI_FILE_PROTOCOL *This,
IN OUT UINTN *BufferSize,
IN VOID *Buffer
)
{
VIRTIO_FS_FILE *VirtioFsFile;
VIRTIO_FS *VirtioFs;
EFI_STATUS Status;
UINTN Transferred;
UINTN Left;
VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);
VirtioFs = VirtioFsFile->OwnerFs;
if (VirtioFsFile->IsDirectory) {
return EFI_UNSUPPORTED;
}
if (!VirtioFsFile->IsOpenForWriting) {
return EFI_ACCESS_DENIED;
}
Status = EFI_SUCCESS;
Transferred = 0;
Left = *BufferSize;
while (Left > 0) {
UINT32 WriteSize;
//
// Honor the write buffer size limit.
//
WriteSize = (UINT32)MIN ((UINTN)VirtioFs->MaxWrite, Left);
Status = VirtioFsFuseWrite (
VirtioFs,
VirtioFsFile->NodeId,
VirtioFsFile->FuseHandle,
VirtioFsFile->FilePosition + Transferred,
&WriteSize,
(UINT8 *)Buffer + Transferred
);
if (!EFI_ERROR (Status) && (WriteSize == 0)) {
//
// Progress should have been made.
//
Status = EFI_DEVICE_ERROR;
}
if (EFI_ERROR (Status)) {
break;
}
Transferred += WriteSize;
Left -= WriteSize;
}
*BufferSize = Transferred;
VirtioFsFile->FilePosition += Transferred;
//
// According to the UEFI spec,
//
// - 'Partial writes only occur when there has been a data error during the
// write attempt (such as "file space full")', and
//
// - (as an example) EFI_VOLUME_FULL is returned when 'The volume is full'.
//
// These together imply that after a partial write, we have to return an
// error. In other words, (Transferred > 0) is inconsequential for the return
// value.
//
return Status;
}
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