[edk2] [PATCH 2/4] MdeModulePkg: Initial UDF/ECMA-167 file system support

Paulo Alcantara posted 4 patches 7 years, 4 months ago
There is a newer version of this series
[edk2] [PATCH 2/4] MdeModulePkg: Initial UDF/ECMA-167 file system support
Posted by Paulo Alcantara 7 years, 4 months ago
A new child device handle will be installed if the Controller handle which
has BlockIo and DiskIo contains an UDF 2.00 (or higher) volume in it.

Find root directory, lookup and open operations on regular, directory and
symlink files are supported.

Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Paulo Alcantara <pcacjr@zytor.com>
---
 MdeModulePkg/Universal/Disk/UdfDxe/ComponentName.c |  185 ++
 MdeModulePkg/Universal/Disk/UdfDxe/File.c          |  651 ++++++
 MdeModulePkg/Universal/Disk/UdfDxe/FileName.c      |  195 ++
 .../Universal/Disk/UdfDxe/FileSystemOperations.c   | 2472 ++++++++++++++++++++
 MdeModulePkg/Universal/Disk/UdfDxe/Udf.c           |  407 ++++
 MdeModulePkg/Universal/Disk/UdfDxe/Udf.h           | 1243 ++++++++++
 MdeModulePkg/Universal/Disk/UdfDxe/UdfDxe.inf      |   66 +
 7 files changed, 5219 insertions(+)
 create mode 100644 MdeModulePkg/Universal/Disk/UdfDxe/ComponentName.c
 create mode 100644 MdeModulePkg/Universal/Disk/UdfDxe/File.c
 create mode 100644 MdeModulePkg/Universal/Disk/UdfDxe/FileName.c
 create mode 100644 MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c
 create mode 100644 MdeModulePkg/Universal/Disk/UdfDxe/Udf.c
 create mode 100644 MdeModulePkg/Universal/Disk/UdfDxe/Udf.h
 create mode 100644 MdeModulePkg/Universal/Disk/UdfDxe/UdfDxe.inf

diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/ComponentName.c b/MdeModulePkg/Universal/Disk/UdfDxe/ComponentName.c
new file mode 100644
index 0000000000..0b0d6afbf0
--- /dev/null
+++ b/MdeModulePkg/Universal/Disk/UdfDxe/ComponentName.c
@@ -0,0 +1,185 @@
+/** @file
+  UEFI Component Name protocol for UDF/ECMA-167 file system driver.
+
+  Copyright (C) 2014-2017 Paulo Alcantara <pcacjr@zytor.com>
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#include "Udf.h"
+
+//
+// EFI Component Name Protocol
+//
+GLOBAL_REMOVE_IF_UNREFERENCED EFI_COMPONENT_NAME_PROTOCOL  gUdfComponentName = {
+  UdfComponentNameGetDriverName,
+  UdfComponentNameGetControllerName,
+  "eng"
+};
+
+//
+// EFI Component Name 2 Protocol
+//
+GLOBAL_REMOVE_IF_UNREFERENCED EFI_COMPONENT_NAME2_PROTOCOL gUdfComponentName2 = {
+  (EFI_COMPONENT_NAME2_GET_DRIVER_NAME) UdfComponentNameGetDriverName,
+  (EFI_COMPONENT_NAME2_GET_CONTROLLER_NAME) UdfComponentNameGetControllerName,
+  "en"
+};
+
+//
+// Driver name table for Udf module.
+// It is shared by the implementation of ComponentName & ComponentName2 Protocol.
+//
+GLOBAL_REMOVE_IF_UNREFERENCED EFI_UNICODE_STRING_TABLE mUdfDriverNameTable[] = {
+  {
+    "eng;en",
+    L"UDF Filesystem Driver"
+  },
+  {
+    NULL,
+    NULL
+  }
+};
+
+/**
+  Retrieves a Unicode string that is the user readable name of the driver.
+
+  This function retrieves the user readable name of a driver in the form of a
+  Unicode string. If the driver specified by This has a user readable name in
+  the language specified by Language, then a pointer to the driver name is
+  returned in DriverName, and EFI_SUCCESS is returned. If the driver specified
+  by This does not support the language specified by Language,
+  then EFI_UNSUPPORTED is returned.
+
+  @param  This[in]              A pointer to the EFI_COMPONENT_NAME2_PROTOCOL or
+                                EFI_COMPONENT_NAME_PROTOCOL instance.
+
+  @param  Language[in]          A pointer to a Null-terminated ASCII string
+                                array indicating the language. This is the
+                                language of the driver name that the caller is
+                                requesting, and it must match one of the
+                                languages specified in SupportedLanguages. The
+                                number of languages supported by a driver is up
+                                to the driver writer. Language is specified
+                                in RFC 4646 or ISO 639-2 language code format.
+
+  @param  DriverName[out]       A pointer to the Unicode string to return.
+                                This Unicode string is the name of the
+                                driver specified by This in the language
+                                specified by Language.
+
+  @retval EFI_SUCCESS           The Unicode string for the Driver specified by
+                                This and the language specified by Language was
+                                returned in DriverName.
+
+  @retval EFI_INVALID_PARAMETER Language is NULL.
+
+  @retval EFI_INVALID_PARAMETER DriverName is NULL.
+
+  @retval EFI_UNSUPPORTED       The driver specified by This does not support
+                                the language specified by Language.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfComponentNameGetDriverName (
+  IN   EFI_COMPONENT_NAME_PROTOCOL  *This,
+  IN   CHAR8                        *Language,
+  OUT  CHAR16                       **DriverName
+  )
+{
+  return LookupUnicodeString2 (
+    Language,
+    This->SupportedLanguages,
+    mUdfDriverNameTable,
+    DriverName,
+    (BOOLEAN)(This == &gUdfComponentName)
+    );
+}
+
+/**
+  Retrieves a Unicode string that is the user readable name of the controller
+  that is being managed by a driver.
+
+  This function retrieves the user readable name of the controller specified by
+  ControllerHandle and ChildHandle in the form of a Unicode string. If the
+  driver specified by This has a user readable name in the language specified by
+  Language, then a pointer to the controller name is returned in ControllerName,
+  and EFI_SUCCESS is returned.  If the driver specified by This is not currently
+  managing the controller specified by ControllerHandle and ChildHandle,
+  then EFI_UNSUPPORTED is returned.  If the driver specified by This does not
+  support the language specified by Language, then EFI_UNSUPPORTED is returned.
+
+  @param  This[in]              A pointer to the EFI_COMPONENT_NAME2_PROTOCOL or
+                                EFI_COMPONENT_NAME_PROTOCOL instance.
+
+  @param  ControllerHandle[in]  The handle of a controller that the driver
+                                specified by This is managing.  This handle
+                                specifies the controller whose name is to be
+                                returned.
+
+  @param  ChildHandle[in]       The handle of the child controller to retrieve
+                                the name of.  This is an optional parameter that
+                                may be NULL.  It will be NULL for device
+                                drivers.  It will also be NULL for a bus drivers
+                                that wish to retrieve the name of the bus
+                                controller.  It will not be NULL for a bus
+                                driver that wishes to retrieve the name of a
+                                child controller.
+
+  @param  Language[in]          A pointer to a Null-terminated ASCII string
+                                array indicating the language.  This is the
+                                language of the driver name that the caller is
+                                requesting, and it must match one of the
+                                languages specified in SupportedLanguages. The
+                                number of languages supported by a driver is up
+                                to the driver writer. Language is specified in
+                                RFC 4646 or ISO 639-2 language code format.
+
+  @param  ControllerName[out]   A pointer to the Unicode string to return.
+                                This Unicode string is the name of the
+                                controller specified by ControllerHandle and
+                                ChildHandle in the language specified by
+                                Language from the point of view of the driver
+                                specified by This.
+
+  @retval EFI_SUCCESS           The Unicode string for the user readable name in
+                                the language specified by Language for the
+                                driver specified by This was returned in
+                                DriverName.
+
+  @retval EFI_INVALID_PARAMETER ControllerHandle is NULL.
+
+  @retval EFI_INVALID_PARAMETER ChildHandle is not NULL and it is not a valid
+                                EFI_HANDLE.
+
+  @retval EFI_INVALID_PARAMETER Language is NULL.
+
+  @retval EFI_INVALID_PARAMETER ControllerName is NULL.
+
+  @retval EFI_UNSUPPORTED       The driver specified by This is not currently
+                                managing the controller specified by
+                                ControllerHandle and ChildHandle.
+
+  @retval EFI_UNSUPPORTED       The driver specified by This does not support
+                                the language specified by Language.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfComponentNameGetControllerName (
+  IN   EFI_COMPONENT_NAME_PROTOCOL  *This,
+  IN   EFI_HANDLE                   ControllerHandle,
+  IN   EFI_HANDLE                   ChildHandle OPTIONAL,
+  IN   CHAR8                        *Language,
+  OUT  CHAR16                       **ControllerName
+  )
+{
+  return EFI_UNSUPPORTED;
+}
diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/File.c b/MdeModulePkg/Universal/Disk/UdfDxe/File.c
new file mode 100644
index 0000000000..dcb9ff2cf5
--- /dev/null
+++ b/MdeModulePkg/Universal/Disk/UdfDxe/File.c
@@ -0,0 +1,651 @@
+/** @file
+  Handle operations in files and directories from UDF/ECMA-167 file systems.
+
+  Copyright (C) 2014-2017 Paulo Alcantara <pcacjr@zytor.com>
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#include "Udf.h"
+
+EFI_FILE_PROTOCOL gUdfFileIoOps = {
+  EFI_FILE_PROTOCOL_REVISION,
+  UdfOpen,
+  UdfClose,
+  UdfDelete,
+  UdfRead,
+  UdfWrite,
+  UdfGetPosition,
+  UdfSetPosition,
+  UdfGetInfo,
+  UdfSetInfo,
+  UdfFlush,
+  NULL,
+  NULL,
+  NULL,
+  NULL
+};
+
+#define _ROOT_FILE(_PrivData) (_PrivData)->Root
+#define _PARENT_FILE(_PrivData) \
+  ((_PrivData)->IsRootDirectory ? (_PrivData)->Root : &(_PrivData)->File)
+#define _FILE(_PrivData) _PARENT_FILE(_PrivData)
+
+/**
+  Open the root directory on a volume.
+
+  @param  This Protocol instance pointer.
+  @param  Root Returns an Open file handle for the root directory
+
+  @retval EFI_SUCCESS          The device was opened.
+  @retval EFI_UNSUPPORTED      This volume does not support the file system.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_ACCESS_DENIED    The service denied access to the file.
+  @retval EFI_OUT_OF_RESOURCES The volume was not opened due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfOpenVolume (
+  IN   EFI_SIMPLE_FILE_SYSTEM_PROTOCOL  *This,
+  OUT  EFI_FILE_PROTOCOL                **Root
+  )
+{
+  EFI_TPL                     OldTpl;
+  EFI_STATUS                  Status;
+  PRIVATE_UDF_SIMPLE_FS_DATA  *PrivFsData;
+  PRIVATE_UDF_FILE_DATA       *PrivFileData;
+
+  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
+
+  if (This == NULL || Root == NULL) {
+    Status = EFI_INVALID_PARAMETER;
+    goto Error_Invalid_Params;
+  }
+
+  PrivFsData = PRIVATE_UDF_SIMPLE_FS_DATA_FROM_THIS (This);
+
+  if (PrivFsData->OpenFiles == 0) {
+    //
+    // There is no more open files. Read volume information again since it was
+    // cleaned up on the last UdfClose() call.
+    //
+    Status = ReadUdfVolumeInformation (
+      PrivFsData->BlockIo,
+      PrivFsData->DiskIo,
+      &PrivFsData->Volume
+      );
+    if (EFI_ERROR (Status)) {
+      goto Error_Read_Udf_Volume;
+    }
+  }
+
+  CleanupFileInformation (&PrivFsData->Root);
+
+  //
+  // Find root directory file.
+  //
+  Status = FindRootDirectory (PrivFsData->BlockIo,
+                              PrivFsData->DiskIo,
+                              &PrivFsData->Volume,
+                              &PrivFsData->Root);
+  if (EFI_ERROR (Status)) {
+    goto Error_Find_Root_Dir;
+  }
+
+  PrivFileData =
+    (PRIVATE_UDF_FILE_DATA *) AllocateZeroPool (sizeof (PRIVATE_UDF_FILE_DATA));
+  if (PrivFileData == NULL) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto Error_Alloc_Priv_File_Data;
+  }
+
+  PrivFileData->Signature        = PRIVATE_UDF_FILE_DATA_SIGNATURE;
+  PrivFileData->SimpleFs         = This;
+  PrivFileData->Root             = &PrivFsData->Root;
+  PrivFileData->IsRootDirectory  = TRUE;
+
+  CopyMem ((VOID *)&PrivFileData->FileIo, (VOID *)&gUdfFileIoOps,
+           sizeof (EFI_FILE_PROTOCOL));
+
+  *Root = &PrivFileData->FileIo;
+
+  PrivFsData->OpenFiles++;
+
+  gBS->RestoreTPL (OldTpl);
+
+  return EFI_SUCCESS;
+
+Error_Alloc_Priv_File_Data:
+  CleanupFileInformation (&PrivFsData->Root);
+
+Error_Find_Root_Dir:
+  CleanupVolumeInformation (&PrivFsData->Volume);
+
+Error_Read_Udf_Volume:
+Error_Invalid_Params:
+  gBS->RestoreTPL (OldTpl);
+
+  return Status;
+}
+
+/**
+  Opens a new file relative to the source file's location.
+
+  @param  This       The protocol instance pointer.
+  @param  NewHandle  Returns File Handle for FileName.
+  @param  FileName   Null terminated string. "\", ".", and ".." are supported.
+  @param  OpenMode   Open mode for file.
+  @param  Attributes Only used for EFI_FILE_MODE_CREATE.
+
+  @retval EFI_SUCCESS          The device was opened.
+  @retval EFI_NOT_FOUND        The specified file could not be found on the
+                               device.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_MEDIA_CHANGED    The media has changed.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_ACCESS_DENIED    The service denied access to the file.
+  @retval EFI_OUT_OF_RESOURCES The volume was not opened due to lack of
+                               resources.
+  @retval EFI_VOLUME_FULL      The volume is full.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfOpen (
+  IN   EFI_FILE_PROTOCOL  *This,
+  OUT  EFI_FILE_PROTOCOL  **NewHandle,
+  IN   CHAR16             *FileName,
+  IN   UINT64             OpenMode,
+  IN   UINT64             Attributes
+  )
+{
+  EFI_TPL                     OldTpl;
+  EFI_STATUS                  Status;
+  PRIVATE_UDF_FILE_DATA       *PrivFileData;
+  PRIVATE_UDF_SIMPLE_FS_DATA  *PrivFsData;
+  CHAR16                      FilePath[UDF_PATH_LENGTH] = { 0 };
+  UDF_FILE_INFO               File;
+  PRIVATE_UDF_FILE_DATA       *NewPrivFileData;
+  CHAR16                      *TempFileName;
+
+  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
+
+  if (This == NULL || NewHandle == NULL || FileName == NULL) {
+    Status = EFI_INVALID_PARAMETER;
+    goto Error_Invalid_Params;
+  }
+
+  if (OpenMode != EFI_FILE_MODE_READ) {
+    Status = EFI_WRITE_PROTECTED;
+    goto Error_Invalid_Params;
+  }
+
+  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);
+
+  PrivFsData = PRIVATE_UDF_SIMPLE_FS_DATA_FROM_THIS (PrivFileData->SimpleFs);
+
+  //
+  // Build full path
+  //
+  if (FileName[0] == L'\\') {
+    StrCpyS (FilePath, UDF_PATH_LENGTH, FileName);
+  } else {
+    StrCpyS (FilePath, UDF_PATH_LENGTH, PrivFileData->AbsoluteFileName);
+    StrCatS (FilePath, UDF_PATH_LENGTH, L"\\");
+    StrCatS (FilePath, UDF_PATH_LENGTH, FileName);
+  }
+
+  MangleFileName (FilePath);
+  if (FilePath[0] == L'\0') {
+    Status = EFI_NOT_FOUND;
+    goto Error_Bad_FileName;
+  }
+
+  Status = FindFile (
+    PrivFsData->BlockIo,
+    PrivFsData->DiskIo,
+    &PrivFsData->Volume,
+    FilePath,
+    _ROOT_FILE (PrivFileData),
+    _PARENT_FILE (PrivFileData),
+    &_PARENT_FILE(PrivFileData)->FileIdentifierDesc->Icb,
+    &File
+    );
+  if (EFI_ERROR (Status)) {
+    goto Error_Find_File;
+  }
+
+  NewPrivFileData =
+    (PRIVATE_UDF_FILE_DATA *)AllocateZeroPool (sizeof (PRIVATE_UDF_FILE_DATA));
+  if (NewPrivFileData == NULL) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto Error_Alloc_New_Priv_File_Data;
+  }
+
+  CopyMem ((VOID *)NewPrivFileData, (VOID *)PrivFileData,
+           sizeof (PRIVATE_UDF_FILE_DATA));
+  CopyMem ((VOID *)&NewPrivFileData->File, &File, sizeof (UDF_FILE_INFO));
+
+  NewPrivFileData->IsRootDirectory = FALSE;
+
+  StrCpyS (NewPrivFileData->AbsoluteFileName, UDF_PATH_LENGTH, FilePath);
+  FileName = NewPrivFileData->AbsoluteFileName;
+
+  while ((TempFileName = StrStr (FileName, L"\\")) != NULL) {
+    FileName = TempFileName + 1;
+  }
+
+  StrCpyS (NewPrivFileData->FileName, UDF_PATH_LENGTH, FileName);
+  Status = GetFileSize (
+    PrivFsData->BlockIo,
+    PrivFsData->DiskIo,
+    &PrivFsData->Volume,
+    &NewPrivFileData->File,
+    &NewPrivFileData->FileSize
+    );
+  if (EFI_ERROR (Status)) {
+    goto Error_Get_File_Size;
+  }
+
+  NewPrivFileData->FilePosition = 0;
+  ZeroMem ((VOID *)&NewPrivFileData->ReadDirInfo,
+           sizeof (UDF_READ_DIRECTORY_INFO));
+
+  *NewHandle = &NewPrivFileData->FileIo;
+
+  PrivFsData->OpenFiles++;
+
+  gBS->RestoreTPL (OldTpl);
+
+  return Status;
+
+Error_Get_File_Size:
+  FreePool ((VOID *)NewPrivFileData);
+
+Error_Alloc_New_Priv_File_Data:
+  CleanupFileInformation (&File);
+
+Error_Find_File:
+Error_Bad_FileName:
+Error_Invalid_Params:
+  gBS->RestoreTPL (OldTpl);
+
+  return Status;
+}
+
+/**
+  Read data from the file.
+
+  @param  This       Protocol instance pointer.
+  @param  BufferSize On input size of buffer, on output amount of data in
+                     buffer.
+  @param  Buffer     The buffer in which data is read.
+
+  @retval EFI_SUCCESS          Data was read.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_BUFFER_TO_SMALL  BufferSize is too small. BufferSize contains
+                               required size.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfRead (
+  IN      EFI_FILE_PROTOCOL  *This,
+  IN OUT  UINTN              *BufferSize,
+  OUT     VOID               *Buffer
+  )
+{
+  return EFI_VOLUME_CORRUPTED;
+}
+
+/**
+  Close the file handle.
+
+  @param  This Protocol instance pointer.
+
+  @retval EFI_SUCCESS The file was closed.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfClose (
+  IN EFI_FILE_PROTOCOL *This
+  )
+{
+  EFI_TPL                     OldTpl;
+  EFI_STATUS                  Status;
+  PRIVATE_UDF_FILE_DATA       *PrivFileData;
+  PRIVATE_UDF_SIMPLE_FS_DATA  *PrivFsData;
+
+  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
+
+  Status = EFI_SUCCESS;
+
+  if (This == NULL) {
+    Status = EFI_INVALID_PARAMETER;
+    goto Exit;
+  }
+
+  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);
+
+  PrivFsData = PRIVATE_UDF_SIMPLE_FS_DATA_FROM_THIS (PrivFileData->SimpleFs);
+
+  if (!PrivFileData->IsRootDirectory) {
+    CleanupFileInformation (&PrivFileData->File);
+
+    if (PrivFileData->ReadDirInfo.DirectoryData) {
+      FreePool (PrivFileData->ReadDirInfo.DirectoryData);
+    }
+  }
+
+  if (--PrivFsData->OpenFiles == 0) {
+    CleanupVolumeInformation (&PrivFsData->Volume);
+  }
+
+  FreePool ((VOID *)PrivFileData);
+
+Exit:
+  gBS->RestoreTPL (OldTpl);
+
+  return Status;
+}
+
+/**
+  Close and delete the file handle.
+
+  @param  This                     Protocol instance pointer.
+
+  @retval EFI_SUCCESS              The file was closed and deleted.
+  @retval EFI_WARN_DELETE_FAILURE  The handle was closed but the file was not
+                                   deleted.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfDelete (
+  IN EFI_FILE_PROTOCOL  *This
+  )
+{
+  PRIVATE_UDF_FILE_DATA *PrivFileData;
+
+  if (This == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);
+
+  (VOID)PrivFileData->FileIo.Close(This);
+
+  return EFI_WARN_DELETE_FAILURE;
+}
+
+/**
+  Write data to a file.
+
+  @param  This       Protocol instance pointer.
+  @param  BufferSize On input size of buffer, on output amount of data in
+                     buffer.
+  @param  Buffer     The buffer in which data to write.
+
+  @retval EFI_SUCCESS          Data was written.
+  @retval EFI_UNSUPPORTED      Writes to Open directory are not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_DEVICE_ERROR     An attempt was made to write to a deleted file.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_WRITE_PROTECTED  The device is write protected.
+  @retval EFI_ACCESS_DENIED    The file was open for read only.
+  @retval EFI_VOLUME_FULL      The volume is full.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfWrite (
+  IN      EFI_FILE_PROTOCOL  *This,
+  IN OUT  UINTN              *BufferSize,
+  IN      VOID               *Buffer
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Get file's current position.
+
+  @param  This      Protocol instance pointer.
+  @param  Position  Byte position from the start of the file.
+
+  @retval EFI_SUCCESS      Position was updated.
+  @retval EFI_UNSUPPORTED  Seek request for directories is not valid.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfGetPosition (
+  IN   EFI_FILE_PROTOCOL  *This,
+  OUT  UINT64             *Position
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Set file's current position.
+
+  @param  This      Protocol instance pointer.
+  @param  Position  Byte position from the start of the file.
+
+  @retval EFI_SUCCESS      Position was updated.
+  @retval EFI_UNSUPPORTED  Seek request for non-zero is not valid on open.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfSetPosition (
+  IN EFI_FILE_PROTOCOL  *This,
+  IN UINT64             Position
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Get information about a file.
+
+  @param  This            Protocol instance pointer.
+  @param  InformationType Type of information to return in Buffer.
+  @param  BufferSize      On input size of buffer, on output amount of data in
+                          buffer.
+  @param  Buffer          The buffer to return data.
+
+  @retval EFI_SUCCESS          Data was returned.
+  @retval EFI_UNSUPPORTED      InformationType is not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_WRITE_PROTECTED  The device is write protected.
+  @retval EFI_ACCESS_DENIED    The file was open for read only.
+  @retval EFI_BUFFER_TOO_SMALL Buffer was too small; required size returned in
+                               BufferSize.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfGetInfo (
+  IN      EFI_FILE_PROTOCOL  *This,
+  IN      EFI_GUID           *InformationType,
+  IN OUT  UINTN              *BufferSize,
+  OUT     VOID               *Buffer
+  )
+{
+  EFI_STATUS                  Status;
+  PRIVATE_UDF_FILE_DATA       *PrivFileData;
+  PRIVATE_UDF_SIMPLE_FS_DATA  *PrivFsData;
+  EFI_FILE_SYSTEM_INFO        *FileSystemInfo;
+  UINTN                       FileSystemInfoLength;
+  CHAR16                      *String;
+  UDF_FILE_SET_DESCRIPTOR     *FileSetDesc;
+  UINTN                       Index;
+  UINT8                       *OstaCompressed;
+  UINT8                       CompressionId;
+  UINT64                      VolumeSize;
+  UINT64                      FreeSpaceSize;
+  CHAR16                      VolumeLabel[64];
+
+  if (This == NULL || InformationType == NULL || BufferSize == 0 ||
+      (*BufferSize != 0 && Buffer == NULL)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);
+
+  PrivFsData = PRIVATE_UDF_SIMPLE_FS_DATA_FROM_THIS (PrivFileData->SimpleFs);
+
+  Status = EFI_UNSUPPORTED;
+
+  if (CompareGuid (InformationType, &gEfiFileInfoGuid)) {
+    Status = SetFileInfo (
+      _FILE (PrivFileData),
+      PrivFileData->FileSize,
+      PrivFileData->FileName,
+      BufferSize,
+      Buffer
+      );
+  } else if (CompareGuid (InformationType, &gEfiFileSystemInfoGuid)) {
+    String = VolumeLabel;
+
+    FileSetDesc = PrivFsData->Volume.FileSetDescs[0];
+
+    OstaCompressed = &FileSetDesc->LogicalVolumeIdentifier[0];
+
+    CompressionId = OstaCompressed[0];
+    if (!IS_VALID_COMPRESSION_ID (CompressionId)) {
+      return EFI_VOLUME_CORRUPTED;
+    }
+
+    for (Index = 1; Index < 128; Index++) {
+      if (CompressionId == 16) {
+        *String = *(UINT8 *)(OstaCompressed + Index) << 8;
+        Index++;
+      } else {
+        *String = 0;
+      }
+
+      if (Index < 128) {
+        *String |= *(UINT8 *)(OstaCompressed + Index);
+      }
+
+      //
+      // Unlike FID Identifiers, Logical Volume Identifier is stored in a
+      // NULL-terminated OSTA compressed format, so we must check for the NULL
+      // character.
+      //
+      if (!*String) {
+        break;
+      }
+
+      String++;
+    }
+
+    *String = L'\0';
+
+    FileSystemInfoLength = StrSize (VolumeLabel) +
+                           sizeof (EFI_FILE_SYSTEM_INFO);
+    if (*BufferSize < FileSystemInfoLength) {
+      *BufferSize = FileSystemInfoLength;
+      return EFI_BUFFER_TOO_SMALL;
+    }
+
+    FileSystemInfo = (EFI_FILE_SYSTEM_INFO *)Buffer;
+    StrCpyS (FileSystemInfo->VolumeLabel, ARRAY_SIZE (VolumeLabel),
+             VolumeLabel);
+    Status = GetVolumeSize (
+      PrivFsData->BlockIo,
+      PrivFsData->DiskIo,
+      &PrivFsData->Volume,
+      &VolumeSize,
+      &FreeSpaceSize
+      );
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+
+    FileSystemInfo->Size        = FileSystemInfoLength;
+    FileSystemInfo->ReadOnly    = TRUE;
+    FileSystemInfo->BlockSize   =
+      LV_BLOCK_SIZE (&PrivFsData->Volume, UDF_DEFAULT_LV_NUM);
+    FileSystemInfo->VolumeSize  = VolumeSize;
+    FileSystemInfo->FreeSpace   = FreeSpaceSize;
+
+    *BufferSize = FileSystemInfoLength;
+    Status = EFI_SUCCESS;
+  }
+
+  return Status;
+}
+
+/**
+  Set information about a file.
+
+  @param  File            Protocol instance pointer.
+  @param  InformationType Type of information in Buffer.
+  @param  BufferSize      Size of buffer.
+  @param  Buffer          The data to write.
+
+  @retval EFI_SUCCESS          Data was set.
+  @retval EFI_UNSUPPORTED      InformationType is not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_WRITE_PROTECTED  The device is write protected.
+  @retval EFI_ACCESS_DENIED    The file was open for read only.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfSetInfo (
+  IN EFI_FILE_PROTOCOL  *This,
+  IN EFI_GUID           *InformationType,
+  IN UINTN              BufferSize,
+  IN VOID               *Buffer
+  )
+{
+  return EFI_WRITE_PROTECTED;
+}
+
+/**
+  Flush data back for the file handle.
+
+  @param  This Protocol instance pointer.
+
+  @retval EFI_SUCCESS          Data was flushed.
+  @retval EFI_UNSUPPORTED      Writes to Open directory are not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_WRITE_PROTECTED  The device is write protected.
+  @retval EFI_ACCESS_DENIED    The file was open for read only.
+  @retval EFI_VOLUME_FULL      The volume is full.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfFlush (
+  IN EFI_FILE_PROTOCOL *This
+  )
+{
+  return EFI_WRITE_PROTECTED;
+}
diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/FileName.c b/MdeModulePkg/Universal/Disk/UdfDxe/FileName.c
new file mode 100644
index 0000000000..1c4bd091bf
--- /dev/null
+++ b/MdeModulePkg/Universal/Disk/UdfDxe/FileName.c
@@ -0,0 +1,195 @@
+/** @file
+  Helper functions for mangling file names in UDF/ECMA-167 file systems.
+
+  Copyright (C) 2014-2017 Paulo Alcantara <pcacjr@zytor.com>
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#include "Udf.h"
+
+CHAR16 *
+TrimString (
+  IN CHAR16    *String
+  )
+{
+  CHAR16       *TempString;
+
+  for ( ; *String != L'\0' && *String == L' '; String++) {
+    ;
+  }
+
+  TempString = String + StrLen (String) - 1;
+  while ((TempString >= String) && (*TempString == L' ')) {
+    TempString--;
+  }
+
+  *(TempString + 1) = L'\0';
+
+  return String;
+}
+
+VOID
+ReplaceLeft (
+  IN CHAR16         *Destination,
+  IN CONST CHAR16   *Source
+  )
+{
+  CONST CHAR16      *EndString;
+
+  EndString = Source + StrLen (Source);
+  while (Source <= EndString) {
+    *Destination++ = *Source++;
+  }
+}
+
+CHAR16 *
+ExcludeTrailingBackslashes (
+  IN CHAR16                    *String
+  )
+{
+  CHAR16                       *TempString;
+
+  switch (*(String + 1)) {
+  case L'\\':
+    break;
+  case L'\0':
+  default:
+    String++;
+    goto Exit;
+  }
+
+  TempString = String;
+  while (*TempString != L'\0' && *TempString == L'\\') {
+    TempString++;
+  }
+
+  if (TempString - 1 > String) {
+    ReplaceLeft (String + 1, TempString);
+  }
+
+  String++;
+
+Exit:
+  return String;
+}
+
+/**
+  Mangle a filename by cutting off trailing whitespaces, "\\", "." and "..".
+
+  @param[in] FileName Filename.
+
+  @retval @p FileName Filename mangled.
+
+**/
+CHAR16 *
+MangleFileName (
+  IN CHAR16        *FileName
+  )
+{
+  CHAR16           *FileNameSavedPointer;
+  CHAR16           *TempFileName;
+  UINTN            BackslashesNo;
+
+  if (FileName == NULL || *FileName == L'\0') {
+    FileName = NULL;
+    goto Exit;
+  }
+
+  FileName = TrimString (FileName);
+  if (*FileName == L'\0') {
+    goto Exit;
+  }
+
+  if ((StrLen (FileName) > 1) && (FileName[StrLen (FileName) - 1] == L'\\')) {
+    FileName[StrLen (FileName) - 1] = L'\0';
+  }
+
+  FileNameSavedPointer = FileName;
+
+  if (FileName[0] == L'.') {
+    if (FileName[1] == L'.') {
+      if (FileName[2] == L'\0') {
+        goto Exit;
+      } else {
+        FileName += 2;
+      }
+    } else if (FileName[1] == L'\0') {
+      goto Exit;
+    }
+  }
+
+  while (*FileName != L'\0') {
+    if (*FileName == L'\\') {
+      FileName = ExcludeTrailingBackslashes (FileName);
+    } else if (*FileName == L'.') {
+      switch (*(FileName + 1)) {
+      case L'\0':
+        *FileName = L'\0';
+        break;
+      case L'\\':
+        TempFileName = FileName + 1;
+        TempFileName = ExcludeTrailingBackslashes (TempFileName);
+        ReplaceLeft (FileName, TempFileName);
+        break;
+      case '.':
+        if ((*(FileName - 1) != L'\\') && ((*(FileName + 2) != L'\\') ||
+                                           (*(FileName + 2) != L'\0'))) {
+          FileName++;
+          continue;
+        }
+
+        BackslashesNo = 0;
+        TempFileName = FileName - 1;
+        while (TempFileName >= FileNameSavedPointer) {
+          if (*TempFileName == L'\\') {
+            if (++BackslashesNo == 2) {
+              break;
+            }
+          }
+
+          TempFileName--;
+        }
+
+        TempFileName++;
+
+        if ((*TempFileName == L'.') && (*(TempFileName + 1) == L'.')) {
+          FileName += 2;
+        } else {
+          if (*(FileName + 2) != L'\0') {
+            ReplaceLeft (TempFileName, FileName + 3);
+            if (*(TempFileName - 1) == L'\\') {
+              FileName = TempFileName;
+              ExcludeTrailingBackslashes (TempFileName - 1);
+              TempFileName = FileName;
+            }
+          } else {
+            *TempFileName = L'\0';
+          }
+
+          FileName = TempFileName;
+        }
+
+        break;
+      default:
+        FileName++;
+      }
+    } else {
+      FileName++;
+    }
+  }
+
+  FileName = FileNameSavedPointer;
+  if ((StrLen (FileName) > 1) && (FileName [StrLen (FileName) - 1] == L'\\')) {
+    FileName [StrLen (FileName) - 1] = L'\0';
+  }
+
+Exit:
+  return FileName;
+}
diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c b/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c
new file mode 100644
index 0000000000..2f7f945479
--- /dev/null
+++ b/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c
@@ -0,0 +1,2472 @@
+/** @file
+  Handle on-disk format and volume structures in UDF/ECMA-167 file systems.
+
+  Copyright (C) 2014-2017 Paulo Alcantara <pcacjr@zytor.com>
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#include "Udf.h"
+
+//
+// This driver *only* supports UDF revision 2.00 or higher.
+//
+// Note the "NSR03" identifier.
+//
+UDF_STANDARD_IDENTIFIER gUdfStandardIdentifiers[NR_STANDARD_IDENTIFIERS] = {
+  { { 'B', 'E', 'A', '0', '1' } },
+  { { 'N', 'S', 'R', '0', '3' } },
+  { { 'T', 'E', 'A', '0', '1' } },
+};
+
+EFI_STATUS
+FindAnchorVolumeDescriptorPointer (
+  IN   EFI_BLOCK_IO_PROTOCOL                 *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL                  *DiskIo,
+  OUT  UDF_ANCHOR_VOLUME_DESCRIPTOR_POINTER  *AnchorPoint
+  )
+{
+  EFI_STATUS  Status;
+  UINT32      BlockSize;
+  EFI_LBA     EndLBA;
+
+  BlockSize  = BlockIo->Media->BlockSize;
+  EndLBA     = BlockIo->Media->LastBlock;
+
+  //
+  // Look for AVDP at LBA 256.
+  //
+  Status = DiskIo->ReadDisk (
+    DiskIo,
+    BlockIo->Media->MediaId,
+    256ULL * BlockSize,
+    sizeof (UDF_ANCHOR_VOLUME_DESCRIPTOR_POINTER),
+    (VOID *)AnchorPoint
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  if (IS_AVDP (AnchorPoint)) {
+    return EFI_SUCCESS;
+  }
+
+  //
+  // Look for AVDP at last LBA - 256.
+  //
+  Status = DiskIo->ReadDisk (
+    DiskIo,
+    BlockIo->Media->MediaId,
+    MultU64x32 (EndLBA - 256, BlockSize),
+    sizeof (UDF_ANCHOR_VOLUME_DESCRIPTOR_POINTER),
+    (VOID *)AnchorPoint
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  if (IS_AVDP (AnchorPoint)) {
+    return EFI_SUCCESS;
+  }
+
+  //
+  // Look for AVDP at last LBA.
+  //
+  Status = DiskIo->ReadDisk (
+    DiskIo,
+    BlockIo->Media->MediaId,
+    MultU64x32 (EndLBA, BlockSize),
+    sizeof (UDF_ANCHOR_VOLUME_DESCRIPTOR_POINTER),
+    (VOID *)AnchorPoint
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  if (IS_AVDP (AnchorPoint)) {
+    return EFI_SUCCESS;
+  }
+
+  //
+  // No AVDP found in this media.
+  //
+  return EFI_VOLUME_CORRUPTED;
+}
+
+EFI_STATUS
+StartMainVolumeDescriptorSequence (
+  IN   EFI_BLOCK_IO_PROTOCOL                 *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL                  *DiskIo,
+  IN   UDF_ANCHOR_VOLUME_DESCRIPTOR_POINTER  *AnchorPoint,
+  OUT  UDF_VOLUME_INFO                       *Volume
+  )
+{
+  EFI_STATUS                     Status;
+  UINT32                         BlockSize;
+  UDF_EXTENT_AD                  *ExtentAd;
+  UINT64                         StartingLsn;
+  UINT64                         EndingLsn;
+  VOID                           *Buffer;
+  UDF_LOGICAL_VOLUME_DESCRIPTOR  *LogicalVolDesc;
+  UDF_PARTITION_DESCRIPTOR       *PartitionDesc;
+  UINTN                          Index;
+  UINT32                         LogicalBlockSize;
+
+  //
+  // We've alreay found an ADVP on the volume. It contains the extent
+  // (MainVolumeDescriptorSequenceExtent) where the Main Volume Descriptor
+  // Sequence starts. Therefore, we'll look for Logical Volume Descriptors and
+  // Partitions Descriptors and save them in memory accordingly.
+  //
+  // Note also that each descriptor will be aligned on a block size (BlockSize)
+  // boundary, so we need to read one block at a time.
+  //
+  BlockSize    = BlockIo->Media->BlockSize;
+  ExtentAd     = &AnchorPoint->MainVolumeDescriptorSequenceExtent;
+  StartingLsn  = (UINT64)ExtentAd->ExtentLocation;
+  EndingLsn    = StartingLsn + DivU64x32 (
+                                     (UINT64)ExtentAd->ExtentLength,
+                                     BlockSize
+                                     );
+
+  Volume->LogicalVolDescs =
+    (UDF_LOGICAL_VOLUME_DESCRIPTOR **)AllocateZeroPool (ExtentAd->ExtentLength);
+  if (Volume->LogicalVolDescs == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  Volume->PartitionDescs =
+    (UDF_PARTITION_DESCRIPTOR **)AllocateZeroPool (ExtentAd->ExtentLength);
+  if (Volume->PartitionDescs == NULL) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto Error_Alloc_Pds;
+  }
+
+  Buffer = AllocateZeroPool (BlockSize);
+  if (Buffer == NULL) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto Error_Alloc_Buf;
+  }
+
+  Volume->LogicalVolDescsNo  = 0;
+  Volume->PartitionDescsNo   = 0;
+
+  while (StartingLsn <= EndingLsn) {
+    Status = DiskIo->ReadDisk (
+      DiskIo,
+      BlockIo->Media->MediaId,
+      MultU64x32 (StartingLsn, BlockSize),
+      BlockSize,
+      Buffer
+      );
+    if (EFI_ERROR (Status)) {
+      goto Error_Read_Disk_Blk;
+    }
+
+    if (IS_TD (Buffer)) {
+      //
+      // Found a Terminating Descriptor. Stop the sequence then.
+      //
+      break;
+    }
+
+    if (IS_LVD (Buffer)) {
+      //
+      // Found a Logical Volume Descriptor.
+      //
+      LogicalVolDesc =
+        (UDF_LOGICAL_VOLUME_DESCRIPTOR *)
+        AllocateZeroPool (sizeof (UDF_LOGICAL_VOLUME_DESCRIPTOR));
+      if (LogicalVolDesc == NULL) {
+        Status = EFI_OUT_OF_RESOURCES;
+        goto Error_Alloc_Lvd;
+      }
+
+      CopyMem ((VOID *)LogicalVolDesc, Buffer,
+               sizeof (UDF_LOGICAL_VOLUME_DESCRIPTOR));
+
+      Volume->LogicalVolDescs[Volume->LogicalVolDescsNo] = LogicalVolDesc;
+      Volume->LogicalVolDescsNo++;
+    } else if (IS_PD (Buffer)) {
+      //
+      // Found a Partition Descriptor.
+      //
+      PartitionDesc =
+        (UDF_PARTITION_DESCRIPTOR *)
+        AllocateZeroPool (sizeof (UDF_PARTITION_DESCRIPTOR));
+      if (PartitionDesc == NULL) {
+        Status = EFI_OUT_OF_RESOURCES;
+        goto Error_Alloc_Pd;
+      }
+
+      CopyMem ((VOID *)PartitionDesc, Buffer,
+               sizeof (UDF_PARTITION_DESCRIPTOR));
+
+      Volume->PartitionDescs[Volume->PartitionDescsNo] = PartitionDesc;
+      Volume->PartitionDescsNo++;
+    }
+
+    StartingLsn++;
+  }
+
+  //
+  // When an UDF volume (revision 2.00 or higher) contains a File Entry rather
+  // than an Extended File Entry (which is not recommended as per spec), we need
+  // to make sure the size of a FE will be _at least_ 2048
+  // (UDF_LOGICAL_SECTOR_SIZE) bytes long to keep backward compatibility.
+  //
+  LogicalBlockSize = LV_BLOCK_SIZE (Volume, UDF_DEFAULT_LV_NUM);
+  if (LogicalBlockSize >= UDF_LOGICAL_SECTOR_SIZE) {
+    Volume->FileEntrySize = LogicalBlockSize;
+  } else {
+    Volume->FileEntrySize = UDF_LOGICAL_SECTOR_SIZE;
+  }
+
+  FreePool (Buffer);
+
+  return EFI_SUCCESS;
+
+Error_Alloc_Pd:
+Error_Alloc_Lvd:
+  for (Index = 0; Index < Volume->PartitionDescsNo; Index++) {
+    FreePool ((VOID *)Volume->PartitionDescs[Index]);
+  }
+
+  for (Index = 0; Index < Volume->LogicalVolDescsNo; Index++) {
+    FreePool ((VOID *)Volume->LogicalVolDescs[Index]);
+  }
+
+Error_Read_Disk_Blk:
+  FreePool (Buffer);
+
+Error_Alloc_Buf:
+  FreePool ((VOID *)Volume->PartitionDescs);
+  Volume->PartitionDescs = NULL;
+
+Error_Alloc_Pds:
+  FreePool ((VOID *)Volume->LogicalVolDescs);
+  Volume->LogicalVolDescs = NULL;
+
+  return Status;
+}
+
+//
+// Return a Partition Descriptor given a Long Allocation Descriptor. This is
+// necessary to calculate the right extent (LongAd) offset which is added up
+// with partition's starting location.
+//
+UDF_PARTITION_DESCRIPTOR *
+GetPdFromLongAd (
+  IN UDF_VOLUME_INFO                 *Volume,
+  IN UDF_LONG_ALLOCATION_DESCRIPTOR  *LongAd
+  )
+{
+  UINTN                     Index;
+  UDF_PARTITION_DESCRIPTOR  *PartitionDesc;
+  UINT16                    PartitionNum;
+
+  for (Index = 0; Index < Volume->PartitionDescsNo; Index++) {
+    PartitionDesc = Volume->PartitionDescs[Index];
+
+    PartitionNum = PartitionDesc->PartitionNumber;
+    if (PartitionNum == LongAd->ExtentLocation.PartitionReferenceNumber) {
+      return PartitionDesc;
+    }
+  }
+
+  return NULL;
+}
+
+//
+// Return logical sector number of the given Long Allocation Descriptor.
+//
+UINT64
+GetLongAdLsn (
+  IN UDF_VOLUME_INFO                 *Volume,
+  IN UDF_LONG_ALLOCATION_DESCRIPTOR  *LongAd
+  )
+{
+  UDF_PARTITION_DESCRIPTOR *PartitionDesc;
+
+  PartitionDesc = GetPdFromLongAd (Volume, LongAd);
+
+  return (UINT64)PartitionDesc->PartitionStartingLocation +
+                 LongAd->ExtentLocation.LogicalBlockNumber;
+}
+
+//
+// Return logical sector number of the given Short Allocation Descriptor.
+//
+UINT64
+GetShortAdLsn (
+  IN UDF_PARTITION_DESCRIPTOR         *PartitionDesc,
+  IN UDF_SHORT_ALLOCATION_DESCRIPTOR  *ShortAd
+  )
+{
+  return (UINT64)PartitionDesc->PartitionStartingLocation +
+                 ShortAd->ExtentPosition;
+}
+
+//
+// Find File Set Descriptor of the given Logical Volume Descriptor.
+//
+// The found FSD will contain the extent (LogicalVolumeContentsUse) where our
+// root directory is.
+//
+EFI_STATUS
+FindFileSetDescriptor (
+  IN   EFI_BLOCK_IO_PROTOCOL    *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL     *DiskIo,
+  IN   UDF_VOLUME_INFO          *Volume,
+  IN   UINTN                    LogicalVolDescNo,
+  OUT  UDF_FILE_SET_DESCRIPTOR  *FileSetDesc
+  )
+{
+  EFI_STATUS                     Status;
+  UINT64                         Lsn;
+  UDF_LOGICAL_VOLUME_DESCRIPTOR  *LogicalVolDesc;
+
+  LogicalVolDesc  = Volume->LogicalVolDescs[LogicalVolDescNo];
+  Lsn             = GetLongAdLsn (Volume,
+                                  &LogicalVolDesc->LogicalVolumeContentsUse);
+
+  //
+  // Read extent (Long Ad).
+  //
+  Status = DiskIo->ReadDisk (
+    DiskIo,
+    BlockIo->Media->MediaId,
+    MultU64x32 (Lsn, LogicalVolDesc->LogicalBlockSize),
+    sizeof (UDF_FILE_SET_DESCRIPTOR),
+    (VOID *)FileSetDesc
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  //
+  // Check if the read extent contains a valid FSD's tag identifier.
+  //
+  if (!IS_FSD (FileSetDesc)) {
+    return EFI_VOLUME_CORRUPTED;
+  }
+
+  return EFI_SUCCESS;
+}
+
+//
+// Get all File Set Descriptors for each Logical Volume Descriptor.
+//
+EFI_STATUS
+GetFileSetDescriptors (
+  IN      EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN      EFI_DISK_IO_PROTOCOL   *DiskIo,
+  IN OUT  UDF_VOLUME_INFO        *Volume
+  )
+{
+  EFI_STATUS               Status;
+  UINTN                    Index;
+  UDF_FILE_SET_DESCRIPTOR  *FileSetDesc;
+  UINTN                    Count;
+
+  Volume->FileSetDescs =
+    (UDF_FILE_SET_DESCRIPTOR **)AllocateZeroPool (
+      Volume->LogicalVolDescsNo * sizeof (UDF_FILE_SET_DESCRIPTOR));
+  if (Volume->FileSetDescs == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  for (Index = 0; Index < Volume->LogicalVolDescsNo; Index++) {
+    FileSetDesc = AllocateZeroPool (sizeof (UDF_FILE_SET_DESCRIPTOR));
+    if (!FileSetDesc) {
+      Status = EFI_OUT_OF_RESOURCES;
+      goto Error_Alloc_Fsd;
+    }
+
+    //
+    // Find a FSD for this LVD.
+    //
+    Status = FindFileSetDescriptor (
+      BlockIo,
+      DiskIo,
+      Volume,
+      Index,
+      FileSetDesc
+      );
+    if (EFI_ERROR (Status)) {
+      goto Error_Find_Fsd;
+    }
+
+    //
+    // Got one. Save it.
+    //
+    Volume->FileSetDescs[Index] = FileSetDesc;
+  }
+
+  Volume->FileSetDescsNo = Volume->LogicalVolDescsNo;
+
+  return EFI_SUCCESS;
+
+Error_Find_Fsd:
+  Count = Index + 1;
+  for (Index = 0; Index < Count; Index++) {
+    FreePool ((VOID *)Volume->FileSetDescs[Index]);
+  }
+
+  FreePool ((VOID *)Volume->FileSetDescs);
+  Volume->FileSetDescs = NULL;
+
+Error_Alloc_Fsd:
+  return Status;
+}
+
+//
+// Read Volume and File Structure of an UDF file system.
+//
+EFI_STATUS
+ReadVolumeFileStructure (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  OUT  UDF_VOLUME_INFO        *Volume
+  )
+{
+  EFI_STATUS                            Status;
+  UDF_ANCHOR_VOLUME_DESCRIPTOR_POINTER  AnchorPoint;
+
+  //
+  // Find an AVDP.
+  //
+  Status = FindAnchorVolumeDescriptorPointer (
+    BlockIo,
+    DiskIo,
+    &AnchorPoint
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  //
+  // AVDP has been found. Start MVDS.
+  //
+  Status = StartMainVolumeDescriptorSequence (
+    BlockIo,
+    DiskIo,
+    &AnchorPoint,
+    Volume
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  return Status;
+}
+
+//
+// Calculate length of the given File Identifier Descriptor.
+//
+UINT64
+GetFidDescriptorLength (
+  IN UDF_FILE_IDENTIFIER_DESCRIPTOR  *FileIdentifierDesc
+  )
+{
+  return (UINT64)(
+             (INTN)((OFFSET_OF (UDF_FILE_IDENTIFIER_DESCRIPTOR, Data[0]) + 3 +
+		     FileIdentifierDesc->LengthOfFileIdentifier +
+		     FileIdentifierDesc->LengthOfImplementationUse) >> 2) << 2
+             );
+}
+
+//
+// Duplicate a given File Identifier Descriptor.
+//
+VOID
+DuplicateFid (
+  IN   UDF_FILE_IDENTIFIER_DESCRIPTOR  *FileIdentifierDesc,
+  OUT  UDF_FILE_IDENTIFIER_DESCRIPTOR  **NewFileIdentifierDesc
+  )
+{
+  *NewFileIdentifierDesc =
+    (UDF_FILE_IDENTIFIER_DESCRIPTOR *)AllocateCopyPool (
+      GetFidDescriptorLength (FileIdentifierDesc), FileIdentifierDesc);
+}
+
+//
+// Duplicate either a given File Entry or a given Extended File Entry.
+//
+VOID
+DuplicateFe (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   UDF_VOLUME_INFO        *Volume,
+  IN   VOID                   *FileEntry,
+  OUT  VOID                   **NewFileEntry
+  )
+{
+  *NewFileEntry = AllocateCopyPool (Volume->FileEntrySize, FileEntry);
+}
+
+//
+// Get raw data + length of the given File Entry or Extended File Entry.
+//
+// The file's recorded data can contain either real file content (inline) or
+// a sequence of extents (or Allocation Descriptors) which tells where file's
+// content is stored in.
+//
+// NOTE: The FE/EFE can be thought it was an inode.
+//
+VOID
+GetFileEntryData (
+  IN   VOID    *FileEntryData,
+  OUT  VOID    **Data,
+  OUT  UINT64  *Length
+  )
+{
+  UDF_EXTENDED_FILE_ENTRY  *ExtendedFileEntry;
+  UDF_FILE_ENTRY           *FileEntry;
+
+  if (IS_EFE (FileEntryData)) {
+    ExtendedFileEntry = (UDF_EXTENDED_FILE_ENTRY *)FileEntryData;
+
+    *Length  = ExtendedFileEntry->InformationLength;
+    *Data    = (VOID *)((UINT8 *)&ExtendedFileEntry->Data[0] +
+                        ExtendedFileEntry->LengthOfExtendedAttributes);
+  } else if (IS_FE (FileEntryData)) {
+    FileEntry = (UDF_FILE_ENTRY *)FileEntryData;
+
+    *Length  = FileEntry->InformationLength;
+    *Data    = (VOID *)((UINT8 *)&FileEntry->Data[0] +
+                        FileEntry->LengthOfExtendedAttributes);
+  }
+}
+
+//
+// Get Allocation Descriptors' data information from the given FE/EFE.
+//
+VOID
+GetAdsInformation (
+  IN   VOID    *FileEntryData,
+  OUT  VOID    **AdsData,
+  OUT  UINT64  *Length
+  )
+{
+  UDF_EXTENDED_FILE_ENTRY  *ExtendedFileEntry;
+  UDF_FILE_ENTRY           *FileEntry;
+
+  if (IS_EFE (FileEntryData)) {
+    ExtendedFileEntry = (UDF_EXTENDED_FILE_ENTRY *)FileEntryData;
+
+    *Length = ExtendedFileEntry->LengthOfAllocationDescriptors;
+    *AdsData = (VOID *)((UINT8 *)&ExtendedFileEntry->Data[0] +
+                        ExtendedFileEntry->LengthOfExtendedAttributes);
+  } else if (IS_FE (FileEntryData)) {
+    FileEntry = (UDF_FILE_ENTRY *)FileEntryData;
+
+    *Length = FileEntry->LengthOfAllocationDescriptors;
+    *AdsData = (VOID *)((UINT8 *)&FileEntry->Data[0] +
+                        FileEntry->LengthOfExtendedAttributes);
+  }
+}
+
+//
+// Read next Short Allocation Descriptor from the given file's data.
+//
+EFI_STATUS
+GetLongAdFromAds (
+  IN      VOID                            *Data,
+  IN OUT  UINT64                          *Offset,
+  IN      UINT64                          Length,
+  OUT     UDF_LONG_ALLOCATION_DESCRIPTOR  **FoundLongAd
+  )
+{
+  UDF_LONG_ALLOCATION_DESCRIPTOR  *LongAd;
+  UDF_EXTENT_FLAGS                ExtentFlags;
+
+  for (;;) {
+    if (*Offset >= Length) {
+      //
+      // No more Long Allocation Descriptors.
+      //
+      return EFI_DEVICE_ERROR;
+    }
+
+    LongAd =
+      (UDF_LONG_ALLOCATION_DESCRIPTOR *)((UINT8 *)Data + *Offset);
+
+    //
+    // If it's either an indirect AD (Extended Alllocation Descriptor) or an
+    // allocated AD, then return it.
+    //
+    ExtentFlags = GET_EXTENT_FLAGS (LONG_ADS_SEQUENCE, LongAd);
+    if (ExtentFlags == EXTENT_IS_NEXT_EXTENT ||
+        ExtentFlags == EXTENT_RECORDED_AND_ALLOCATED) {
+      break;
+    }
+
+    //
+    // This AD is either not recorded but allocated, or not recorded and not
+    // allocated. Skip it.
+    //
+    *Offset += AD_LENGTH (LONG_ADS_SEQUENCE);
+  }
+
+  *FoundLongAd = LongAd;
+
+  return EFI_SUCCESS;
+}
+
+//
+// Read next Short Allocation Descriptor from the given file's data.
+//
+EFI_STATUS
+GetShortAdFromAds (
+  IN      VOID                             *Data,
+  IN OUT  UINT64                           *Offset,
+  IN      UINT64                           Length,
+  OUT     UDF_SHORT_ALLOCATION_DESCRIPTOR  **FoundShortAd
+  )
+{
+  UDF_SHORT_ALLOCATION_DESCRIPTOR *ShortAd;
+  UDF_EXTENT_FLAGS                ExtentFlags;
+
+  for (;;) {
+    if (*Offset >= Length) {
+      //
+      // No more Short Allocation Descriptors.
+      //
+      return EFI_DEVICE_ERROR;
+    }
+
+    ShortAd =
+      (UDF_SHORT_ALLOCATION_DESCRIPTOR *)((UINT8 *)Data + *Offset);
+
+    //
+    // If it's either an indirect AD (Extended Alllocation Descriptor) or an
+    // allocated AD, then return it.
+    //
+    ExtentFlags = GET_EXTENT_FLAGS (SHORT_ADS_SEQUENCE, ShortAd);
+    if (ExtentFlags == EXTENT_IS_NEXT_EXTENT ||
+        ExtentFlags == EXTENT_RECORDED_AND_ALLOCATED) {
+      break;
+    }
+
+    //
+    // This AD is either not recorded but allocated, or not recorded and not
+    // allocated. Skip it.
+    //
+    *Offset += AD_LENGTH (SHORT_ADS_SEQUENCE);
+  }
+
+  *FoundShortAd = ShortAd;
+
+  return EFI_SUCCESS;
+}
+
+//
+// Get either a Short Allocation Descriptor or a Long Allocation Descriptor from
+// the given file's data.
+//
+EFI_STATUS
+GetAllocationDescriptor (
+  IN      UDF_FE_RECORDING_FLAGS  RecordingFlags,
+  IN      VOID                    *Data,
+  IN OUT  UINT64                  *Offset,
+  IN      UINT64                  Length,
+  OUT     VOID                    **FoundAd
+  )
+{
+  if (RecordingFlags == LONG_ADS_SEQUENCE) {
+    return GetLongAdFromAds (
+      Data,
+      Offset,
+      Length,
+      (UDF_LONG_ALLOCATION_DESCRIPTOR **)FoundAd
+      );
+  } else if (RecordingFlags == SHORT_ADS_SEQUENCE) {
+    return GetShortAdFromAds (
+      Data,
+      Offset,
+      Length,
+      (UDF_SHORT_ALLOCATION_DESCRIPTOR **)FoundAd
+      );
+  }
+
+  return EFI_DEVICE_ERROR;
+}
+
+//
+// Return logical sector number of either Short or Long Allocation Descriptor.
+//
+UINT64
+GetAllocationDescriptorLsn (
+  IN UDF_FE_RECORDING_FLAGS          RecordingFlags,
+  IN UDF_VOLUME_INFO                 *Volume,
+  IN UDF_LONG_ALLOCATION_DESCRIPTOR  *ParentIcb,
+  IN VOID                            *Ad
+  )
+{
+  if (RecordingFlags == LONG_ADS_SEQUENCE) {
+    return GetLongAdLsn (Volume, (UDF_LONG_ALLOCATION_DESCRIPTOR *)Ad);
+  } else if (RecordingFlags == SHORT_ADS_SEQUENCE) {
+    return GetShortAdLsn (
+      GetPdFromLongAd (Volume, ParentIcb),
+      (UDF_SHORT_ALLOCATION_DESCRIPTOR *)Ad
+      );
+  }
+
+  return 0;
+}
+
+//
+// Return offset + length of a given indirect Allocation Descriptor (AED).
+//
+EFI_STATUS
+GetAedAdsOffset (
+  IN   EFI_BLOCK_IO_PROTOCOL           *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL            *DiskIo,
+  IN   UDF_VOLUME_INFO                 *Volume,
+  IN   UDF_LONG_ALLOCATION_DESCRIPTOR  *ParentIcb,
+  IN   UDF_FE_RECORDING_FLAGS          RecordingFlags,
+  IN   VOID                            *Ad,
+  OUT  UINT64                          *Offset,
+  OUT  UINT64                          *Length
+  )
+{
+  EFI_STATUS                        Status;
+  UINT32                            ExtentLength;
+  UINT64                            Lsn;
+  VOID                              *Data;
+  UINT32                            LogicalBlockSize;
+  UDF_ALLOCATION_EXTENT_DESCRIPTOR  *AllocExtDesc;
+
+  ExtentLength  = GET_EXTENT_LENGTH (RecordingFlags, Ad);
+  Lsn           = GetAllocationDescriptorLsn (RecordingFlags,
+                                              Volume,
+                                              ParentIcb,
+                                              Ad);
+
+  Data = AllocatePool (ExtentLength);
+  if (Data == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  LogicalBlockSize = LV_BLOCK_SIZE (Volume, UDF_DEFAULT_LV_NUM);
+
+  //
+  // Read extent.
+  //
+  Status = DiskIo->ReadDisk (
+    DiskIo,
+    BlockIo->Media->MediaId,
+    MultU64x32 (Lsn, LogicalBlockSize),
+    ExtentLength,
+    Data
+    );
+  if (EFI_ERROR (Status)) {
+    goto Exit;
+  }
+
+  //
+  // Check if read extent contains a valid tag identifier for AED.
+  //
+  AllocExtDesc = (UDF_ALLOCATION_EXTENT_DESCRIPTOR *)Data;
+  if (!IS_AED (AllocExtDesc)) {
+    Status = EFI_VOLUME_CORRUPTED;
+    goto Exit;
+  }
+
+  //
+  // Get AED's block offset and its length.
+  //
+  *Offset = MultU64x32 (Lsn, LogicalBlockSize) +
+    sizeof (UDF_ALLOCATION_EXTENT_DESCRIPTOR);
+  *Length = AllocExtDesc->LengthOfAllocationDescriptors;
+
+Exit:
+  FreePool (Data);
+
+  return Status;
+}
+
+//
+// Read Allocation Extent Descriptor into memory.
+//
+EFI_STATUS
+GetAedAdsData (
+  IN   EFI_BLOCK_IO_PROTOCOL           *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL            *DiskIo,
+  IN   UDF_VOLUME_INFO                 *Volume,
+  IN   UDF_LONG_ALLOCATION_DESCRIPTOR  *ParentIcb,
+  IN   UDF_FE_RECORDING_FLAGS          RecordingFlags,
+  IN   VOID                            *Ad,
+  OUT  VOID                            **Data,
+  OUT  UINT64                          *Length
+  )
+{
+  EFI_STATUS  Status;
+  UINT64      Offset;
+
+  //
+  // Get AED's offset + length.
+  //
+  Status = GetAedAdsOffset (
+    BlockIo,
+    DiskIo,
+    Volume,
+    ParentIcb,
+    RecordingFlags,
+    Ad,
+    &Offset,
+    Length
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  //
+  // Allocate buffer to read in AED's data.
+  //
+  *Data = AllocatePool (*Length);
+  if (*Data == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  return DiskIo->ReadDisk (
+    DiskIo,
+    BlockIo->Media->MediaId,
+    Offset,
+    *Length,
+    *Data
+    );
+}
+
+//
+// Function used to serialise reads of Allocation Descriptors.
+//
+EFI_STATUS
+GrowUpBufferToNextAd (
+  IN      UDF_FE_RECORDING_FLAGS  RecordingFlags,
+  IN      VOID                    *Ad,
+  IN OUT  VOID                    **Buffer,
+  IN      UINT64                  Length
+  )
+{
+  UINT32 ExtentLength;
+
+  ExtentLength = GET_EXTENT_LENGTH (RecordingFlags, Ad);
+
+  if (*Buffer == NULL) {
+    *Buffer = AllocatePool (ExtentLength);
+    if (*Buffer == NULL) {
+      return EFI_OUT_OF_RESOURCES;
+    }
+  } else {
+    *Buffer = ReallocatePool (Length, Length + ExtentLength, *Buffer);
+    if (*Buffer == NULL) {
+      return EFI_OUT_OF_RESOURCES;
+    }
+  }
+
+  return EFI_SUCCESS;
+}
+
+//
+// Read data or size of either a File Entry or an Extended File Entry.
+//
+EFI_STATUS
+ReadFile (
+  IN      EFI_BLOCK_IO_PROTOCOL           *BlockIo,
+  IN      EFI_DISK_IO_PROTOCOL            *DiskIo,
+  IN      UDF_VOLUME_INFO                 *Volume,
+  IN      UDF_LONG_ALLOCATION_DESCRIPTOR  *ParentIcb,
+  IN      VOID                            *FileEntryData,
+  IN OUT  UDF_READ_FILE_INFO              *ReadFileInfo
+  )
+{
+  EFI_STATUS              Status;
+  UINT32                  LogicalBlockSize;
+  VOID                    *Data;
+  UINT64                  Length;
+  VOID                    *Ad;
+  UINT64                  AdOffset;
+  UINT64                  Lsn;
+  BOOLEAN                 DoFreeAed;
+  UINT64                  FilePosition;
+  UINT64                  Offset;
+  UINT64                  DataOffset;
+  UINT64                  BytesLeft;
+  UINT64                  DataLength;
+  BOOLEAN                 FinishedSeeking;
+  UINT32                  ExtentLength;
+  UDF_FE_RECORDING_FLAGS  RecordingFlags;
+
+  LogicalBlockSize  = LV_BLOCK_SIZE (Volume, UDF_DEFAULT_LV_NUM);
+  DoFreeAed         = FALSE;
+
+  switch (ReadFileInfo->Flags) {
+  case READ_FILE_GET_FILESIZE:
+  case READ_FILE_ALLOCATE_AND_READ:
+    //
+    // Initialise ReadFileInfo structure for starting get file's size or read
+    // file's recorded data.
+    //
+    ReadFileInfo->ReadLength = 0;
+    ReadFileInfo->FileData = NULL;
+    break;
+  case READ_FILE_SEEK_AND_READ:
+    //
+    // About to seek a file and/or read its data.
+    //
+    Length = ReadFileInfo->FileSize - ReadFileInfo->FilePosition;
+    if (ReadFileInfo->FileDataSize > Length) {
+      //
+      // About to read beyond the EOF -- truncate it.
+      //
+      ReadFileInfo->FileDataSize = Length;
+    }
+
+    //
+    // Initialise data to start seeking and/or reading a file.
+    //
+    BytesLeft = ReadFileInfo->FileDataSize;
+    DataOffset = 0;
+    FilePosition = 0;
+    FinishedSeeking = FALSE;
+
+    break;
+  }
+
+  RecordingFlags = GET_FE_RECORDING_FLAGS (FileEntryData);
+  switch (RecordingFlags) {
+  case INLINE_DATA:
+    //
+    // There is no extents for this FE/EFE. All its data is inline.
+    //
+    GetFileEntryData (FileEntryData, &Data, &Length);
+
+    if (ReadFileInfo->Flags == READ_FILE_GET_FILESIZE) {
+      ReadFileInfo->ReadLength = Length;
+    } else if (ReadFileInfo->Flags == READ_FILE_ALLOCATE_AND_READ) {
+      //
+      // Allocate buffer for starting read data.
+      //
+      ReadFileInfo->FileData = AllocatePool (Length);
+      if (!ReadFileInfo->FileData) {
+        return EFI_OUT_OF_RESOURCES;
+      }
+
+      //
+      // Read all inline data into ReadFileInfo->FileData
+      //
+      CopyMem (ReadFileInfo->FileData, Data, Length);
+      ReadFileInfo->ReadLength = Length;
+    } else if (ReadFileInfo->Flags == READ_FILE_SEEK_AND_READ) {
+      //
+      // If FilePosition is non-zero, seek file to FilePosition, read
+      // FileDataSize bytes and then updates FilePosition.
+      //
+      CopyMem (
+        ReadFileInfo->FileData,
+        (VOID *)((UINT8 *)Data + ReadFileInfo->FilePosition),
+        ReadFileInfo->FileDataSize
+        );
+
+      ReadFileInfo->FilePosition += ReadFileInfo->FileDataSize;
+    }
+
+    break;
+  case LONG_ADS_SEQUENCE:
+  case SHORT_ADS_SEQUENCE:
+    //
+    // This FE/EFE contains a run of Allocation Descriptors. Get data + size
+    // for start reading them.
+    //
+    GetAdsInformation (FileEntryData, &Data, &Length);
+    AdOffset = 0;
+
+    for (;;) {
+      //
+      // Read AD.
+      //
+      Status = GetAllocationDescriptor (
+        RecordingFlags,
+        Data,
+        &AdOffset,
+        Length,
+        &Ad
+        );
+      if (Status == EFI_DEVICE_ERROR) {
+        Status = EFI_SUCCESS;
+        goto Done;
+      }
+
+      //
+      // Check if AD is an indirect one. If so, read Allocation Extent
+      // Descriptor and read their extents (ADs).
+      //
+      if (GET_EXTENT_FLAGS (RecordingFlags, Ad) == EXTENT_IS_NEXT_EXTENT) {
+        if (!DoFreeAed) {
+          DoFreeAed = TRUE;
+        } else {
+          FreePool (Data);
+        }
+
+        Status = GetAedAdsData (
+          BlockIo,
+          DiskIo,
+          Volume,
+          ParentIcb,
+          RecordingFlags,
+          Ad,
+          &Data,
+          &Length
+          );
+        if (EFI_ERROR (Status)) {
+          goto Error_Get_Aed;
+        }
+
+        AdOffset = 0;
+        continue;
+      }
+
+      ExtentLength = GET_EXTENT_LENGTH (RecordingFlags, Ad);
+
+      Lsn = GetAllocationDescriptorLsn (RecordingFlags,
+                                        Volume,
+                                        ParentIcb,
+                                        Ad);
+
+      switch (ReadFileInfo->Flags) {
+	  case READ_FILE_GET_FILESIZE:
+	    ReadFileInfo->ReadLength += ExtentLength;
+	    break;
+	  case READ_FILE_ALLOCATE_AND_READ:
+	    //
+	    // Increase FileData (if necessary) to read next extent.
+	    //
+	    Status = GrowUpBufferToNextAd (
+          RecordingFlags,
+          Ad,
+          &ReadFileInfo->FileData,
+          ReadFileInfo->ReadLength
+          );
+	    if (EFI_ERROR (Status)) {
+	      goto Error_Alloc_Buffer_To_Next_Ad;
+	    }
+
+	    //
+	    // Read extent's data into FileData.
+	    //
+	    Status = DiskIo->ReadDisk (
+          DiskIo,
+          BlockIo->Media->MediaId,
+          MultU64x32 (Lsn, LogicalBlockSize),
+          ExtentLength,
+          (VOID *)((UINT8 *)ReadFileInfo->FileData +
+                   ReadFileInfo->ReadLength)
+          );
+	    if (EFI_ERROR (Status)) {
+	      goto Error_Read_Disk_Blk;
+	    }
+
+	    ReadFileInfo->ReadLength += ExtentLength;
+	    break;
+	  case READ_FILE_SEEK_AND_READ:
+	    //
+	    // Seek file first before reading in its data.
+	    //
+	    if (FinishedSeeking) {
+	      Offset = 0;
+	      goto Skip_File_Seek;
+	    }
+
+	    if (FilePosition + ExtentLength < ReadFileInfo->FilePosition) {
+	      FilePosition += ExtentLength;
+	      goto Skip_Ad;
+	    }
+
+	    if (FilePosition + ExtentLength > ReadFileInfo->FilePosition) {
+	      Offset = ReadFileInfo->FilePosition - FilePosition;
+	      if (Offset < 0) {
+            Offset = -(Offset);
+	      }
+	    } else {
+	      Offset = 0;
+	    }
+
+	    //
+	    // Done with seeking file. Start reading its data.
+	    //
+	    FinishedSeeking = TRUE;
+
+      Skip_File_Seek:
+	    //
+	    // Make sure we don't read more data than really wanted.
+	    //
+	    if (ExtentLength - Offset > BytesLeft) {
+	      DataLength = BytesLeft;
+	    } else {
+	      DataLength = ExtentLength - Offset;
+	    }
+
+	    //
+	    // Read extent's data into FileData.
+	    //
+	    Status = DiskIo->ReadDisk (
+          DiskIo,
+          BlockIo->Media->MediaId,
+          Offset + MultU64x32 (Lsn, LogicalBlockSize),
+          DataLength,
+          (VOID *)((UINT8 *)ReadFileInfo->FileData +
+                   DataOffset)
+          );
+	    if (EFI_ERROR (Status)) {
+	      goto Error_Read_Disk_Blk;
+	    }
+
+        //
+        // Update current file's position.
+	    //
+	    DataOffset += DataLength;
+	    ReadFileInfo->FilePosition += DataLength;
+
+	    BytesLeft -= DataLength;
+	    if (!BytesLeft) {
+	      //
+	      // There is no more file data to read.
+	      //
+	      Status = EFI_SUCCESS;
+	      goto Done;
+	    }
+
+	    break;
+      }
+
+    Skip_Ad:
+      //
+      // Point to the next AD (extent).
+      //
+      AdOffset += AD_LENGTH (RecordingFlags);
+    }
+
+    break;
+  case EXTENDED_ADS_SEQUENCE:
+    // Not supported. Haven't got a volume with that yet.
+    Status = EFI_UNSUPPORTED;
+    break;
+  }
+
+Done:
+  if (DoFreeAed) {
+    FreePool (Data);
+  }
+
+  return Status;
+
+Error_Read_Disk_Blk:
+Error_Alloc_Buffer_To_Next_Ad:
+  if (ReadFileInfo->Flags != READ_FILE_SEEK_AND_READ) {
+    FreePool (ReadFileInfo->FileData);
+  }
+
+  if (DoFreeAed) {
+    FreePool (Data);
+  }
+
+Error_Get_Aed:
+  return Status;
+}
+
+//
+// Find a file by its filename from the given Parent file.
+//
+EFI_STATUS
+InternalFindFile (
+  IN   EFI_BLOCK_IO_PROTOCOL           *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL            *DiskIo,
+  IN   UDF_VOLUME_INFO                 *Volume,
+  IN   CHAR16                          *FileName,
+  IN   UDF_FILE_INFO                   *Parent,
+  IN   UDF_LONG_ALLOCATION_DESCRIPTOR  *Icb,
+  OUT  UDF_FILE_INFO                   *File
+  )
+{
+  EFI_STATUS                      Status;
+  UDF_FILE_IDENTIFIER_DESCRIPTOR  *FileIdentifierDesc;
+  UDF_READ_DIRECTORY_INFO         ReadDirInfo;
+  BOOLEAN                         Found;
+  UINTN                           FileNameLength;
+  CHAR16                          FoundFileName[UDF_FILENAME_LENGTH];
+  VOID                            *CompareFileEntry;
+
+  //
+  // Check if parent file is really directory.
+  //
+  if (!IS_FE_DIRECTORY (Parent->FileEntry)) {
+    return EFI_NOT_FOUND;
+  }
+
+  //
+  // If FileName is current file or working directory, just duplicate Parent's
+  // FE/EFE and FID descriptors.
+  //
+  if (!StrCmp (FileName, L".")) {
+    DuplicateFe (BlockIo, Volume, Parent->FileEntry, &File->FileEntry);
+    DuplicateFid (Parent->FileIdentifierDesc, &File->FileIdentifierDesc);
+
+    return EFI_SUCCESS;
+  }
+
+  //
+  // Start directory listing.
+  //
+  ZeroMem ((VOID *)&ReadDirInfo, sizeof (UDF_READ_DIRECTORY_INFO));
+  Found = FALSE;
+  FileNameLength = StrLen (FileName);
+
+  for (;;) {
+    Status = ReadDirectoryEntry (
+      BlockIo,
+      DiskIo,
+      Volume,
+      Parent->FileIdentifierDesc ?
+      &Parent->FileIdentifierDesc->Icb :
+      Icb,
+      Parent->FileEntry,
+      &ReadDirInfo,
+      &FileIdentifierDesc
+      );
+    if (EFI_ERROR (Status)) {
+      if (Status == EFI_DEVICE_ERROR) {
+        Status = EFI_NOT_FOUND;
+      }
+
+      break;
+    }
+
+    if (IS_FID_PARENT_FILE (FileIdentifierDesc)) {
+      //
+      // This FID contains the location (FE/EFE) of the parent directory of this
+      // directory (Parent), and if FileName is either ".." or "\\", then it's
+      // the expected FID.
+      //
+      if (!StrCmp (FileName, L"..") || !StrCmp (FileName, L"\\")) {
+        Found = TRUE;
+        break;
+      }
+    } else {
+      //
+      // Check if both filename lengths match each other. Otherwise, we don't
+      // need to read in FID's filename.
+      //
+      if (FileNameLength != FileIdentifierDesc->LengthOfFileIdentifier - 1) {
+        goto Skip_Fid;
+      }
+
+      //
+      // OK - their filename lengths match. Now, compare if their filenames.
+      //
+      Status = GetFileNameFromFid (FileIdentifierDesc, FoundFileName);
+      if (EFI_ERROR (Status)) {
+        break;
+      }
+
+      if (!StrCmp (FileName, FoundFileName)) {
+        //
+        // FID has been found. Prepare to find its respective FE/EFE.
+        //
+        Found = TRUE;
+        break;
+      }
+    }
+
+  Skip_Fid:
+    FreePool ((VOID *)FileIdentifierDesc);
+  }
+
+  if (ReadDirInfo.DirectoryData) {
+    //
+    // Free all allocated resources for the directory listing.
+    //
+    FreePool (ReadDirInfo.DirectoryData);
+  }
+
+  if (Found) {
+    Status = EFI_SUCCESS;
+
+    File->FileIdentifierDesc = FileIdentifierDesc;
+
+    //
+    // If the requested file is root directory, then the FE/EFE was already
+    // retrieved in UdfOpenVolume() function, thus no need to find it again.
+    //
+    // Otherwise, find FE/EFE from the respective FID.
+    //
+    if (StrCmp (FileName, L"\\")) {
+      Status = FindFileEntry (
+        BlockIo,
+        DiskIo,
+        Volume,
+        &FileIdentifierDesc->Icb,
+        &CompareFileEntry
+        );
+      if (EFI_ERROR (Status)) {
+        goto Error_Find_Fe;
+      }
+
+      //
+      // Make sure that both Parent's FE/EFE and found FE/EFE are not equal.
+      //
+      if (CompareMem ((VOID *)Parent->FileEntry, (VOID *)CompareFileEntry,
+                      Volume->FileEntrySize) != 0) {
+        File->FileEntry = CompareFileEntry;
+      } else {
+        FreePool ((VOID *)FileIdentifierDesc);
+        FreePool ((VOID *)CompareFileEntry);
+        Status = EFI_NOT_FOUND;
+      }
+    }
+  }
+
+  return Status;
+
+Error_Find_Fe:
+  FreePool ((VOID *)FileIdentifierDesc);
+
+  return Status;
+}
+
+/**
+  Check if medium contains an UDF file system.
+
+  @param[in]   BlockIo  BlockIo interface.
+  @param[in]   DiskIo   DiskIo interface.
+
+  @retval EFI_SUCCESS          UDF file system found.
+  @retval EFI_UNSUPPORTED      UDF file system not found.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The scan was not successful due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+SupportUdfFileSystem (
+  IN EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN EFI_DISK_IO_PROTOCOL   *DiskIo
+  )
+{
+  EFI_STATUS                            Status;
+  UINT64                                Offset;
+  UINT64                                EndDiskOffset;
+  UDF_VOLUME_DESCRIPTOR                 VolDescriptor;
+  UDF_VOLUME_DESCRIPTOR                 TerminatingVolDescriptor;
+  UDF_ANCHOR_VOLUME_DESCRIPTOR_POINTER  AnchorPoint;
+
+  ZeroMem ((VOID *)&TerminatingVolDescriptor, sizeof (UDF_VOLUME_DESCRIPTOR));
+
+  //
+  // Start Volume Recognition Sequence
+  //
+  EndDiskOffset = BlockIo->Media->LastBlock * BlockIo->Media->BlockSize;
+
+  for (Offset = UDF_VRS_START_OFFSET; Offset < EndDiskOffset;
+       Offset += UDF_LOGICAL_SECTOR_SIZE) {
+    Status = DiskIo->ReadDisk (
+      DiskIo,
+      BlockIo->Media->MediaId,
+      Offset,
+      sizeof (UDF_VOLUME_DESCRIPTOR),
+      (VOID *)&VolDescriptor
+      );
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+
+    if (CompareMem ((VOID *)&VolDescriptor.StandardIdentifier,
+                    (VOID *)&gUdfStandardIdentifiers[BEA_IDENTIFIER],
+                    UDF_STANDARD_IDENTIFIER_LENGTH) == 0) {
+      break;
+    }
+
+    if ((CompareMem ((VOID *)&VolDescriptor.StandardIdentifier,
+                     (VOID *)UDF_CDROM_VOLUME_IDENTIFIER,
+                     UDF_STANDARD_IDENTIFIER_LENGTH) != 0) ||
+        (CompareMem ((VOID *)&VolDescriptor,
+                     (VOID *)&TerminatingVolDescriptor,
+                     sizeof (UDF_VOLUME_DESCRIPTOR)) == 0)) {
+      return EFI_UNSUPPORTED;
+    }
+  }
+
+  //
+  // Look for "NSR03" identifier in the Extended Area
+  //
+  Offset += UDF_LOGICAL_SECTOR_SIZE;
+  if (Offset >= EndDiskOffset) {
+    return EFI_UNSUPPORTED;
+  }
+
+  Status = DiskIo->ReadDisk (
+    DiskIo,
+    BlockIo->Media->MediaId,
+    Offset,
+    sizeof (UDF_VOLUME_DESCRIPTOR),
+    (VOID *)&VolDescriptor
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  if (CompareMem ((VOID *)&VolDescriptor.StandardIdentifier,
+                  (VOID *)&gUdfStandardIdentifiers[VSD_IDENTIFIER],
+                  UDF_STANDARD_IDENTIFIER_LENGTH) != 0) {
+    return EFI_UNSUPPORTED;
+  }
+
+  //
+  // Look for "TEA01" identifier in the Extended Area
+  //
+  Offset += UDF_LOGICAL_SECTOR_SIZE;
+  if (Offset >= EndDiskOffset) {
+    return EFI_UNSUPPORTED;
+  }
+
+  Status = DiskIo->ReadDisk (
+    DiskIo,
+    BlockIo->Media->MediaId,
+    Offset,
+    sizeof (UDF_VOLUME_DESCRIPTOR),
+    (VOID *)&VolDescriptor
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  if (CompareMem ((VOID *)&VolDescriptor.StandardIdentifier,
+                  (VOID *)&gUdfStandardIdentifiers[TEA_IDENTIFIER],
+                  UDF_STANDARD_IDENTIFIER_LENGTH) != 0) {
+    return EFI_UNSUPPORTED;
+  }
+
+  Status = FindAnchorVolumeDescriptorPointer (BlockIo, DiskIo, &AnchorPoint);
+  if (EFI_ERROR (Status)) {
+    return EFI_UNSUPPORTED;
+  }
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Read volume information on a medium which contains a valid UDF file system.
+
+  @param[in]   BlockIo  BlockIo interface.
+  @param[in]   DiskIo   DiskIo interface.
+  @param[out]  Volume   UDF volume information structure.
+
+  @retval EFI_SUCCESS          Volume information read.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The volume was not read due to lack of resources.
+
+**/
+EFI_STATUS
+ReadUdfVolumeInformation (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  OUT  UDF_VOLUME_INFO        *Volume
+  )
+{
+  EFI_STATUS Status;
+
+  Status = ReadVolumeFileStructure (
+    BlockIo,
+    DiskIo,
+    Volume
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Status = GetFileSetDescriptors (
+    BlockIo,
+    DiskIo,
+    Volume
+    );
+  if (EFI_ERROR (Status)) {
+    CleanupVolumeInformation (Volume);
+  }
+
+  return Status;
+}
+
+/**
+  Find the root directory on an UDF volume.
+
+  @param[in]   BlockIo  BlockIo interface.
+  @param[in]   DiskIo   DiskIo interface.
+  @param[in]   Volume   UDF volume information structure.
+  @param[out]  File     Root directory file.
+
+  @retval EFI_SUCCESS          Root directory found.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The root directory was not found due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+FindRootDirectory (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  IN   UDF_VOLUME_INFO        *Volume,
+  OUT  UDF_FILE_INFO          *File
+  )
+{
+  EFI_STATUS     Status;
+  UDF_FILE_INFO  Parent;
+
+  Status = FindFileEntry (
+    BlockIo,
+    DiskIo,
+    Volume,
+    &Volume->FileSetDescs[0]->RootDirectoryIcb,
+    &File->FileEntry
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Parent.FileEntry = File->FileEntry;
+  Parent.FileIdentifierDesc = NULL;
+
+  Status = FindFile (
+    BlockIo,
+    DiskIo,
+    Volume,
+    L"\\",
+    NULL,
+    &Parent,
+    &Volume->FileSetDescs[0]->RootDirectoryIcb,
+    File
+    );
+  if (EFI_ERROR (Status)) {
+    FreePool (File->FileEntry);
+  }
+
+  return Status;
+}
+
+/**
+  Find either a File Entry or a Extended File Entry from a given ICB.
+
+  @param[in]   BlockIo    BlockIo interface.
+  @param[in]   DiskIo     DiskIo interface.
+  @param[in]   Volume     UDF volume information structure.
+  @param[in]   Icb        ICB of the FID.
+  @param[out]  FileEntry  File Entry or Extended File Entry.
+
+  @retval EFI_SUCCESS          File Entry or Extended File Entry found.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The FE/EFE entry was not found due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+FindFileEntry (
+  IN   EFI_BLOCK_IO_PROTOCOL           *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL            *DiskIo,
+  IN   UDF_VOLUME_INFO                 *Volume,
+  IN   UDF_LONG_ALLOCATION_DESCRIPTOR  *Icb,
+  OUT  VOID                            **FileEntry
+  )
+{
+  EFI_STATUS  Status;
+  UINT64      Lsn;
+  UINT32      LogicalBlockSize;
+
+  Lsn               = GetLongAdLsn (Volume, Icb);
+  LogicalBlockSize  = LV_BLOCK_SIZE (Volume, UDF_DEFAULT_LV_NUM);
+
+  *FileEntry = AllocateZeroPool (Volume->FileEntrySize);
+  if (*FileEntry == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  //
+  // Read extent.
+  //
+  Status = DiskIo->ReadDisk (
+    DiskIo,
+    BlockIo->Media->MediaId,
+    MultU64x32 (Lsn, LogicalBlockSize),
+    Volume->FileEntrySize,
+    *FileEntry
+    );
+  if (EFI_ERROR (Status)) {
+    goto Error_Read_Disk_Blk;
+  }
+
+  //
+  // Check if the read extent contains a valid Tag Identifier for the expected
+  // FE/EFE.
+  //
+  if (!IS_FE (*FileEntry) && !IS_EFE (*FileEntry)) {
+    Status = EFI_VOLUME_CORRUPTED;
+    goto Error_Invalid_Fe;
+  }
+
+  return EFI_SUCCESS;
+
+Error_Invalid_Fe:
+Error_Read_Disk_Blk:
+  FreePool (*FileEntry);
+
+  return Status;
+}
+
+/**
+  Find a file given its absolute path on an UDF volume.
+
+  @param[in]   BlockIo   BlockIo interface.
+  @param[in]   DiskIo    DiskIo interface.
+  @param[in]   Volume    UDF volume information structure.
+  @param[in]   FilePath  File's absolute path.
+  @param[in]   Root      Root directory file.
+  @param[in]   Parent    Parent directory file.
+  @param[out]  File      Found file.
+
+  @retval EFI_SUCCESS          @p FilePath was found.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The @p FilePath file was not found due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+FindFile (
+  IN   EFI_BLOCK_IO_PROTOCOL           *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL            *DiskIo,
+  IN   UDF_VOLUME_INFO                 *Volume,
+  IN   CHAR16                          *FilePath,
+  IN   UDF_FILE_INFO                   *Root,
+  IN   UDF_FILE_INFO                   *Parent,
+  IN   UDF_LONG_ALLOCATION_DESCRIPTOR  *Icb,
+  OUT  UDF_FILE_INFO                   *File
+  )
+{
+  EFI_STATUS     Status;
+  CHAR16         FileName[UDF_FILENAME_LENGTH];
+  CHAR16         *FileNamePointer;
+  UDF_FILE_INFO  PreviousFile;
+  VOID           *FileEntry;
+
+  Status = EFI_NOT_FOUND;
+
+  CopyMem ((VOID *)&PreviousFile, (VOID *)Parent, sizeof (UDF_FILE_INFO));
+  while (*FilePath != L'\0') {
+    FileNamePointer = FileName;
+    while (*FilePath != L'\0' && *FilePath != L'\\') {
+      *FileNamePointer++ = *FilePath++;
+    }
+
+    *FileNamePointer = L'\0';
+    if (FileName[0] == L'\0') {
+      //
+      // Open root directory.
+      //
+      if (!Root) {
+        //
+        // There is no file found for the root directory yet. So, find only its
+        // FID by now.
+        //
+        // See UdfOpenVolume() function.
+        //
+        Status = InternalFindFile (BlockIo,
+                                   DiskIo,
+                                   Volume,
+                                   L"\\",
+                                   &PreviousFile,
+                                   Icb,
+                                   File);
+      } else {
+        //
+        // We've already a file pointer (Root) for the root directory. Duplicate
+        // its FE/EFE and FID descriptors.
+        //
+        DuplicateFe (BlockIo, Volume, Root->FileEntry, &File->FileEntry);
+        DuplicateFid (Root->FileIdentifierDesc, &File->FileIdentifierDesc);
+        Status = EFI_SUCCESS;
+      }
+    } else {
+      //
+      // No root directory. Find filename from the current directory.
+      //
+      Status = InternalFindFile (BlockIo,
+                                 DiskIo,
+                                 Volume,
+                                 FileName,
+                                 &PreviousFile,
+                                 Icb,
+                                 File);
+    }
+
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+
+    //
+    // If the found file is a symlink, then find its respective FE/EFE and
+    // FID descriptors.
+    //
+    if (IS_FE_SYMLINK (File->FileEntry)) {
+      FreePool ((VOID *)File->FileIdentifierDesc);
+
+      FileEntry = File->FileEntry;
+
+      Status = ResolveSymlink (BlockIo,
+                               DiskIo,
+                               Volume,
+                               &PreviousFile,
+                               FileEntry,
+                               File);
+
+      FreePool (FileEntry);
+
+      if (EFI_ERROR (Status)) {
+        return Status;
+      }
+    }
+
+    if (CompareMem ((VOID *)&PreviousFile, (VOID *)Parent,
+                    sizeof (UDF_FILE_INFO)) != 0) {
+      CleanupFileInformation (&PreviousFile);
+    }
+
+    CopyMem ((VOID *)&PreviousFile, (VOID *)File, sizeof (UDF_FILE_INFO));
+    if (*FilePath != L'\0' && *FilePath == L'\\') {
+      FilePath++;
+    }
+  }
+
+  return Status;
+}
+
+/**
+  Read a directory entry at a time on an UDF volume.
+
+  @param[in]      BlockIo        BlockIo interface.
+  @param[in]      DiskIo         DiskIo interface.
+  @param[in]      Volume         UDF volume information structure.
+  @param[in]      ParentIcb      ICB of the parent file.
+  @param[in]      FileEntryData  FE/EFE of the parent file.
+  @param[in out]  ReadDirInfo    Next read directory listing structure
+                                 information.
+  @param[out]     FoundFid       File Identifier Descriptor pointer.
+
+  @retval EFI_SUCCESS          Directory entry read.
+  @retval EFI_UNSUPPORTED      Extended Allocation Descriptors not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The directory entry was not read due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+ReadDirectoryEntry (
+  IN      EFI_BLOCK_IO_PROTOCOL           *BlockIo,
+  IN      EFI_DISK_IO_PROTOCOL            *DiskIo,
+  IN      UDF_VOLUME_INFO                 *Volume,
+  IN      UDF_LONG_ALLOCATION_DESCRIPTOR  *ParentIcb,
+  IN      VOID                            *FileEntryData,
+  IN OUT  UDF_READ_DIRECTORY_INFO         *ReadDirInfo,
+  OUT     UDF_FILE_IDENTIFIER_DESCRIPTOR  **FoundFid
+  )
+{
+  EFI_STATUS                      Status;
+  UDF_READ_FILE_INFO              ReadFileInfo;
+  UDF_FILE_IDENTIFIER_DESCRIPTOR  *FileIdentifierDesc;
+
+  if (!ReadDirInfo->DirectoryData) {
+    //
+    // The directory's recorded data has not been read yet. So let's cache it
+    // into memory and the next calls won't need to read it again.
+    //
+    ReadFileInfo.Flags = READ_FILE_ALLOCATE_AND_READ;
+
+    Status = ReadFile (
+      BlockIo,
+      DiskIo,
+      Volume,
+      ParentIcb,
+      FileEntryData,
+      &ReadFileInfo
+      );
+    if (EFI_ERROR (Status)) {
+      return Status;
+    }
+
+    //
+    // Fill in ReadDirInfo structure with the read directory's data information.
+    //
+    ReadDirInfo->DirectoryData = ReadFileInfo.FileData;
+    ReadDirInfo->DirectoryLength = ReadFileInfo.ReadLength;
+  }
+
+  do {
+    if (ReadDirInfo->FidOffset >= ReadDirInfo->DirectoryLength) {
+      //
+      // There aren't FIDS for this directory anymore. The EFI_DEVICE_ERROR will
+      // indicate end of directory listing.
+      //
+      return EFI_DEVICE_ERROR;
+    }
+
+    //
+    // Get FID for this entry.
+    //
+    FileIdentifierDesc =
+      GET_FID_FROM_ADS (ReadDirInfo->DirectoryData,
+                        ReadDirInfo->FidOffset);
+    //
+    // Update FidOffset to point to the next FID.
+    //
+    ReadDirInfo->FidOffset += GetFidDescriptorLength (FileIdentifierDesc);
+  } while (IS_FID_DELETED_FILE (FileIdentifierDesc));
+
+  DuplicateFid (FileIdentifierDesc, FoundFid);
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Get a filename (encoded in OSTA-compressed format) from a File Identifier
+  Descriptor on an UDF volume.
+
+  @param[in]   FileIdentifierDesc  File Identifier Descriptor pointer.
+  @param[out]  FileName            Decoded filename.
+
+  @retval EFI_SUCCESS           Filename decoded and read.
+  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
+**/
+EFI_STATUS
+GetFileNameFromFid (
+  IN   UDF_FILE_IDENTIFIER_DESCRIPTOR  *FileIdentifierDesc,
+  OUT  CHAR16                          *FileName
+  )
+{
+  UINT8 *OstaCompressed;
+  UINT8 CompressionId;
+  UINT8 Length;
+  UINTN Index;
+
+  OstaCompressed =
+    (UINT8 *)(
+      (UINT8 *)&FileIdentifierDesc->Data[0] +
+      FileIdentifierDesc->LengthOfImplementationUse
+      );
+
+  CompressionId = OstaCompressed[0];
+  if (!IS_VALID_COMPRESSION_ID (CompressionId)) {
+    return EFI_VOLUME_CORRUPTED;
+  }
+
+  //
+  // Decode filename.
+  //
+  Length = FileIdentifierDesc->LengthOfFileIdentifier;
+  for (Index = 1; Index < Length; Index++) {
+    if (CompressionId == 16) {
+      *FileName = OstaCompressed[Index++] << 8;
+    } else {
+      *FileName = 0;
+    }
+
+    if (Index < Length) {
+      *FileName |= OstaCompressed[Index];
+    }
+
+    FileName++;
+  }
+
+  *FileName = L'\0';
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Resolve a symlink file on an UDF volume.
+
+  @param[in]   BlockIo        BlockIo interface.
+  @param[in]   DiskIo         DiskIo interface.
+  @param[in]   Volume         UDF volume information structure.
+  @param[in]   Parent         Parent file.
+  @param[in]   FileEntryData  FE/EFE structure pointer.
+  @param[out]  File           Resolved file.
+
+  @retval EFI_SUCCESS          Symlink file resolved.
+  @retval EFI_UNSUPPORTED      Extended Allocation Descriptors not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The symlink file was not resolved due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+ResolveSymlink (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  IN   UDF_VOLUME_INFO        *Volume,
+  IN   UDF_FILE_INFO          *Parent,
+  IN   VOID                   *FileEntryData,
+  OUT  UDF_FILE_INFO          *File
+  )
+{
+  EFI_STATUS          Status;
+  UDF_READ_FILE_INFO  ReadFileInfo;
+  UINT8               *Data;
+  UINT64              Length;
+  UINT8               *EndData;
+  UDF_PATH_COMPONENT  *PathComp;
+  UINT8               PathCompLength;
+  CHAR16              FileName[UDF_FILENAME_LENGTH];
+  CHAR16              *C;
+  UINTN               Index;
+  UINT8               CompressionId;
+  UDF_FILE_INFO       PreviousFile;
+
+  //
+  // Symlink files on UDF volumes do not contain so much data other than
+  // Path Components which resolves to real filenames, so it's OK to read in
+  // all its data here -- usually the data will be inline with the FE/EFE for
+  // lower filenames.
+  //
+  ReadFileInfo.Flags = READ_FILE_ALLOCATE_AND_READ;
+
+  Status = ReadFile (
+    BlockIo,
+    DiskIo,
+    Volume,
+    &Parent->FileIdentifierDesc->Icb,
+    FileEntryData,
+    &ReadFileInfo
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Length = ReadFileInfo.ReadLength;
+
+  Data = (UINT8 *)ReadFileInfo.FileData;
+  EndData = Data + Length;
+
+  CopyMem ((VOID *)&PreviousFile, (VOID *)Parent, sizeof (UDF_FILE_INFO));
+
+  for (;;) {
+    PathComp = (UDF_PATH_COMPONENT *)Data;
+
+    PathCompLength = PathComp->LengthOfComponentIdentifier;
+
+    switch (PathComp->ComponentType) {
+    case 1:
+      //
+      // This Path Component specifies the root directory hierarchy subject to
+      // agreement between the originator and recipient of the medium. Skip it.
+      //
+      // Fall through.
+      //
+    case 2:
+      //
+      // "\\." of the current directory. Read next Path Component.
+      //
+      goto Next_Path_Component;
+    case 3:
+      //
+      // ".." (parent directory). Go to it.
+      //
+      CopyMem ((VOID *)FileName, L"..", 6);
+      break;
+    case 4:
+      //
+      // "." (current file). Duplicate both FE/EFE and FID of this file.
+      //
+      DuplicateFe (BlockIo, Volume, PreviousFile.FileEntry, &File->FileEntry);
+      DuplicateFid (PreviousFile.FileIdentifierDesc,
+                    &File->FileIdentifierDesc);
+      goto Next_Path_Component;
+    case 5:
+      //
+      // This Path Component identifies an object, either a file or a
+      // directory or an alias.
+      //
+      // Decode it from the compressed data in ComponentIdentifier and find
+      // respective path.
+      //
+      CompressionId = PathComp->ComponentIdentifier[0];
+      if (!IS_VALID_COMPRESSION_ID (CompressionId)) {
+        return EFI_VOLUME_CORRUPTED;
+      }
+
+      C = FileName;
+      for (Index = 1; Index < PathCompLength; Index++) {
+        if (CompressionId == 16) {
+          *C = *(UINT8 *)((UINT8 *)PathComp->ComponentIdentifier +
+                          Index) << 8;
+          Index++;
+        } else {
+          *C = 0;
+        }
+
+        if (Index < Length) {
+          *C |= *(UINT8 *)((UINT8 *)PathComp->ComponentIdentifier + Index);
+        }
+
+        C++;
+      }
+
+      *C = L'\0';
+      break;
+    }
+
+    //
+    // Find file from the read filename in symlink's file data.
+    //
+    Status = InternalFindFile (
+      BlockIo,
+      DiskIo,
+      Volume,
+      FileName,
+      &PreviousFile,
+      NULL,
+      File
+      );
+    if (EFI_ERROR (Status)) {
+      goto Error_Find_File;
+    }
+
+  Next_Path_Component:
+    Data += sizeof (UDF_PATH_COMPONENT) + PathCompLength;
+    if (Data >= EndData) {
+      break;
+    }
+
+    if (CompareMem ((VOID *)&PreviousFile, (VOID *)Parent,
+                    sizeof (UDF_FILE_INFO)) != 0) {
+      CleanupFileInformation (&PreviousFile);
+    }
+
+    CopyMem ((VOID *)&PreviousFile, (VOID *)File, sizeof (UDF_FILE_INFO));
+  }
+
+  //
+  // Unmap the symlink file.
+  //
+  FreePool (ReadFileInfo.FileData);
+
+  return EFI_SUCCESS;
+
+Error_Find_File:
+  if (CompareMem ((VOID *)&PreviousFile, (VOID *)Parent,
+                  sizeof (UDF_FILE_INFO)) != 0) {
+    CleanupFileInformation (&PreviousFile);
+  }
+
+  FreePool (ReadFileInfo.FileData);
+
+  return Status;
+}
+
+/**
+  Clean up in-memory UDF volume information.
+
+  @param[in] Volume Volume information pointer.
+
+**/
+VOID
+CleanupVolumeInformation (
+  IN UDF_VOLUME_INFO *Volume
+  )
+{
+  UINTN Index;
+
+  if (Volume->LogicalVolDescs != NULL) {
+    for (Index = 0; Index < Volume->LogicalVolDescsNo; Index++) {
+      FreePool ((VOID *)Volume->LogicalVolDescs[Index]);
+    }
+
+    FreePool ((VOID *)Volume->LogicalVolDescs);
+  }
+
+  if (Volume->PartitionDescs != NULL) {
+    for (Index = 0; Index < Volume->PartitionDescsNo; Index++) {
+      FreePool ((VOID *)Volume->PartitionDescs[Index]);
+    }
+
+    FreePool ((VOID *)Volume->PartitionDescs);
+  }
+
+  if (Volume->FileSetDescs != NULL) {
+    for (Index = 0; Index < Volume->FileSetDescsNo; Index++) {
+      FreePool ((VOID *)Volume->FileSetDescs[Index]);
+    }
+
+    FreePool ((VOID *)Volume->FileSetDescs);
+  }
+
+  ZeroMem ((VOID *)Volume, sizeof (UDF_VOLUME_INFO));
+}
+
+/**
+  Clean up in-memory UDF file information.
+
+  @param[in] File File information pointer.
+
+**/
+VOID
+CleanupFileInformation (
+  IN UDF_FILE_INFO *File
+  )
+{
+  if (File->FileEntry != NULL) {
+    FreePool (File->FileEntry);
+  }
+
+  if (File->FileIdentifierDesc != NULL) {
+    FreePool ((VOID *)File->FileIdentifierDesc);
+  }
+
+  ZeroMem ((VOID *)File, sizeof (UDF_FILE_INFO));
+}
+
+/**
+  Find a file from its absolute path on an UDF volume.
+
+  @param[in]   BlockIo  BlockIo interface.
+  @param[in]   DiskIo   DiskIo interface.
+  @param[in]   Volume   UDF volume information structure.
+  @param[in]   File     File information structure.
+  @param[out]  Size     Size of the file.
+
+  @retval EFI_SUCCESS          File size calculated and set in @p Size.
+  @retval EFI_UNSUPPORTED      Extended Allocation Descriptors not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The file size was not calculated due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+GetFileSize (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  IN   UDF_VOLUME_INFO        *Volume,
+  IN   UDF_FILE_INFO          *File,
+  OUT  UINT64                 *Size
+  )
+{
+  EFI_STATUS          Status;
+  UDF_READ_FILE_INFO  ReadFileInfo;
+
+  ReadFileInfo.Flags = READ_FILE_GET_FILESIZE;
+
+  Status = ReadFile (
+    BlockIo,
+    DiskIo,
+    Volume,
+    &File->FileIdentifierDesc->Icb,
+    File->FileEntry,
+    &ReadFileInfo
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  *Size = ReadFileInfo.ReadLength;
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Set information about a file on an UDF volume.
+
+  @param[in]      File        File pointer.
+  @param[in]      FileSize    Size of the file.
+  @param[in]      FileName    Filename of the file.
+  @param[in out]  BufferSize  Size of the returned file infomation.
+  @param[out]     Buffer      Data of the returned file information.
+
+  @retval EFI_SUCCESS          File information set.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The file information was not set due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+SetFileInfo (
+  IN      UDF_FILE_INFO  *File,
+  IN      UINT64         FileSize,
+  IN      CHAR16         *FileName,
+  IN OUT  UINTN          *BufferSize,
+  OUT     VOID           *Buffer
+  )
+{
+  UINTN                    FileInfoLength;
+  EFI_FILE_INFO            *FileInfo;
+  UDF_FILE_ENTRY           *FileEntry;
+  UDF_EXTENDED_FILE_ENTRY  *ExtendedFileEntry;
+
+  //
+  // Calculate the needed size for the EFI_FILE_INFO structure.
+  //
+  FileInfoLength = sizeof (EFI_FILE_INFO) + (FileName ?
+                                             StrSize (FileName) :
+                                             sizeof (CHAR16)
+    );
+  if (*BufferSize < FileInfoLength) {
+    //
+    // The given Buffer has no size enough for EFI_FILE_INFO structure.
+    //
+    *BufferSize = FileInfoLength;
+    return EFI_BUFFER_TOO_SMALL;
+  }
+
+  //
+  // Buffer now contains room enough to store EFI_FILE_INFO structure.
+  // Now, fill it in with all necessary information about the file.
+  //
+  FileInfo = (EFI_FILE_INFO *)Buffer;
+  FileInfo->Size         = FileInfoLength;
+  FileInfo->Attribute    &= ~EFI_FILE_VALID_ATTR;
+  FileInfo->Attribute    |= EFI_FILE_READ_ONLY;
+
+  if (IS_FID_DIRECTORY_FILE (File->FileIdentifierDesc)) {
+    FileInfo->Attribute |= EFI_FILE_DIRECTORY;
+  } else if (IS_FID_NORMAL_FILE (File->FileIdentifierDesc)) {
+    FileInfo->Attribute |= EFI_FILE_ARCHIVE;
+  }
+
+  if (IS_FID_HIDDEN_FILE (File->FileIdentifierDesc)) {
+    FileInfo->Attribute |= EFI_FILE_HIDDEN;
+  }
+
+  if (IS_FE (File->FileEntry)) {
+    FileEntry = (UDF_FILE_ENTRY *)File->FileEntry;
+
+    //
+    // Check if FE has the system attribute set.
+    //
+    if (FileEntry->IcbTag.Flags & (1 << 10)) {
+      FileInfo->Attribute |= EFI_FILE_SYSTEM;
+    }
+
+    FileInfo->FileSize      = FileSize;
+    FileInfo->PhysicalSize  = FileSize;
+
+    FileInfo->CreateTime.Year        = FileEntry->AccessTime.Year;
+    FileInfo->CreateTime.Month       = FileEntry->AccessTime.Month;
+    FileInfo->CreateTime.Day         = FileEntry->AccessTime.Day;
+    FileInfo->CreateTime.Hour        = FileEntry->AccessTime.Hour;
+    FileInfo->CreateTime.Minute      = FileEntry->AccessTime.Second;
+    FileInfo->CreateTime.Second      = FileEntry->AccessTime.Second;
+    FileInfo->CreateTime.Nanosecond  =
+                                   FileEntry->AccessTime.HundredsOfMicroseconds;
+
+    FileInfo->LastAccessTime.Year        =
+                                   FileEntry->AccessTime.Year;
+    FileInfo->LastAccessTime.Month       =
+                                   FileEntry->AccessTime.Month;
+    FileInfo->LastAccessTime.Day         =
+                                   FileEntry->AccessTime.Day;
+    FileInfo->LastAccessTime.Hour        =
+                                   FileEntry->AccessTime.Hour;
+    FileInfo->LastAccessTime.Minute      =
+                                   FileEntry->AccessTime.Minute;
+    FileInfo->LastAccessTime.Second      =
+                                   FileEntry->AccessTime.Second;
+    FileInfo->LastAccessTime.Nanosecond  =
+                                   FileEntry->AccessTime.HundredsOfMicroseconds;
+  } else if (IS_EFE (File->FileEntry)) {
+    ExtendedFileEntry = (UDF_EXTENDED_FILE_ENTRY *)File->FileEntry;
+
+    //
+    // Check if EFE has the system attribute set.
+    //
+    if (ExtendedFileEntry->IcbTag.Flags & (1 << 10)) {
+      FileInfo->Attribute |= EFI_FILE_SYSTEM;
+    }
+
+    FileInfo->FileSize      = FileSize;
+    FileInfo->PhysicalSize  = FileSize;
+
+    FileInfo->CreateTime.Year        = ExtendedFileEntry->CreationTime.Year;
+    FileInfo->CreateTime.Month       = ExtendedFileEntry->CreationTime.Month;
+    FileInfo->CreateTime.Day         = ExtendedFileEntry->CreationTime.Day;
+    FileInfo->CreateTime.Hour        = ExtendedFileEntry->CreationTime.Hour;
+    FileInfo->CreateTime.Minute      = ExtendedFileEntry->CreationTime.Second;
+    FileInfo->CreateTime.Second      = ExtendedFileEntry->CreationTime.Second;
+    FileInfo->CreateTime.Nanosecond  =
+                           ExtendedFileEntry->AccessTime.HundredsOfMicroseconds;
+
+    FileInfo->LastAccessTime.Year        =
+                           ExtendedFileEntry->AccessTime.Year;
+    FileInfo->LastAccessTime.Month       =
+                           ExtendedFileEntry->AccessTime.Month;
+    FileInfo->LastAccessTime.Day         =
+                           ExtendedFileEntry->AccessTime.Day;
+    FileInfo->LastAccessTime.Hour        =
+                           ExtendedFileEntry->AccessTime.Hour;
+    FileInfo->LastAccessTime.Minute      =
+                           ExtendedFileEntry->AccessTime.Minute;
+    FileInfo->LastAccessTime.Second      =
+                           ExtendedFileEntry->AccessTime.Second;
+    FileInfo->LastAccessTime.Nanosecond  =
+                           ExtendedFileEntry->AccessTime.HundredsOfMicroseconds;
+  }
+
+  FileInfo->CreateTime.TimeZone      = EFI_UNSPECIFIED_TIMEZONE;
+  FileInfo->CreateTime.Daylight      = EFI_TIME_ADJUST_DAYLIGHT;
+  FileInfo->LastAccessTime.TimeZone  = EFI_UNSPECIFIED_TIMEZONE;
+  FileInfo->LastAccessTime.Daylight  = EFI_TIME_ADJUST_DAYLIGHT;
+
+  CopyMem ((VOID *)&FileInfo->ModificationTime,
+           (VOID *)&FileInfo->LastAccessTime,
+           sizeof (EFI_TIME));
+
+  if (FileName != NULL) {
+    StrCpyS (FileInfo->FileName, StrLen (FileName) + 1, FileName);
+  } else {
+    FileInfo->FileName[0] = '\0';
+  }
+
+  *BufferSize = FileInfoLength;
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Get volume and free space size information of an UDF volume.
+
+  @param[in]   BlockIo        BlockIo interface.
+  @param[in]   DiskIo         DiskIo interface.
+  @param[in]   Volume         UDF volume information structure.
+  @param[out]  VolumeSize     Volume size.
+  @param[out]  FreeSpaceSize  Free space size.
+
+  @retval EFI_SUCCESS          Volume and free space size calculated.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The volume and free space size were not
+                               calculated due to lack of resources.
+
+**/
+EFI_STATUS
+GetVolumeSize (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  IN   UDF_VOLUME_INFO        *Volume,
+  OUT  UINT64                 *VolumeSize,
+  OUT  UINT64                 *FreeSpaceSize
+  )
+{
+  UDF_EXTENT_AD                 ExtentAd;
+  UINT32                        LogicalBlockSize;
+  UINT64                        Lsn;
+  EFI_STATUS                    Status;
+  UDF_LOGICAL_VOLUME_INTEGRITY  *LogicalVolInt;
+  UINTN                         Index;
+  UINTN                         Length;
+  UINT32                        LsnsNo;
+
+  *VolumeSize     = 0;
+  *FreeSpaceSize  = 0;
+
+  for (Index = 0; Index < Volume->LogicalVolDescsNo; Index++) {
+    CopyMem ((VOID *)&ExtentAd,
+             (VOID *)&Volume->LogicalVolDescs[Index]->IntegritySequenceExtent,
+             sizeof (UDF_EXTENT_AD));
+    if (ExtentAd.ExtentLength == 0) {
+      continue;
+    }
+
+    LogicalBlockSize = LV_BLOCK_SIZE (Volume, Index);
+
+  Read_Next_Sequence:
+    LogicalVolInt = (UDF_LOGICAL_VOLUME_INTEGRITY *)
+      AllocatePool (ExtentAd.ExtentLength);
+    if (LogicalVolInt == NULL) {
+      return EFI_OUT_OF_RESOURCES;
+    }
+
+    Lsn = (UINT64)ExtentAd.ExtentLocation;
+
+    Status = DiskIo->ReadDisk (
+      DiskIo,
+      BlockIo->Media->MediaId,
+      MultU64x32 (Lsn, LogicalBlockSize),
+      ExtentAd.ExtentLength,
+      (VOID *)LogicalVolInt
+      );
+    if (EFI_ERROR (Status)) {
+      FreePool ((VOID *)LogicalVolInt);
+      return Status;
+    }
+
+    if (!IS_LVID (LogicalVolInt)) {
+      FreePool ((VOID *)LogicalVolInt);
+      return EFI_VOLUME_CORRUPTED;
+    }
+
+    Length = LogicalVolInt->NumberOfPartitions;
+    for (Index = 0; Index < Length; Index += sizeof (UINT32)) {
+      LsnsNo = *(UINT32 *)((UINT8 *)&LogicalVolInt->Data[0] + Index);
+      if (LsnsNo == 0xFFFFFFFFUL) {
+        //
+        // Size not specified.
+        //
+        continue;
+      }
+
+      *FreeSpaceSize += MultU64x32 ((UINT64)LsnsNo, LogicalBlockSize);
+    }
+
+    Length = (LogicalVolInt->NumberOfPartitions * sizeof (UINT32)) << 1;
+    for (; Index < Length; Index += sizeof (UINT32)) {
+      LsnsNo = *(UINT32 *)((UINT8 *)&LogicalVolInt->Data[0] + Index);
+      if (LsnsNo == 0xFFFFFFFFUL) {
+        //
+        // Size not specified.
+        //
+        continue;
+      }
+
+      *VolumeSize += MultU64x32 ((UINT64)LsnsNo, LogicalBlockSize);
+    }
+
+    CopyMem ((VOID *)&ExtentAd,(VOID *)&LogicalVolInt->NextIntegrityExtent,
+             sizeof (UDF_EXTENT_AD));
+    if (ExtentAd.ExtentLength > 0) {
+      FreePool ((VOID *)LogicalVolInt);
+      goto Read_Next_Sequence;
+    }
+
+    FreePool ((VOID *)LogicalVolInt);
+  }
+
+  return EFI_SUCCESS;
+}
diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/Udf.c b/MdeModulePkg/Universal/Disk/UdfDxe/Udf.c
new file mode 100644
index 0000000000..1b912fb3a3
--- /dev/null
+++ b/MdeModulePkg/Universal/Disk/UdfDxe/Udf.c
@@ -0,0 +1,407 @@
+/** @file
+  UDF/ECMA-167 file system driver.
+
+  Copyright (C) 2014-2017 Paulo Alcantara <pcacjr@zytor.com>
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#include "Udf.h"
+
+//
+// UDF filesystem driver's Global Variables.
+//
+EFI_DRIVER_BINDING_PROTOCOL gUdfDriverBinding = {
+  UdfDriverBindingSupported,
+  UdfDriverBindingStart,
+  UdfDriverBindingStop,
+  0x0000000BUL,
+  NULL,
+  NULL
+};
+
+typedef struct {
+  VENDOR_DEVICE_PATH        DevicePath;
+  EFI_DEVICE_PATH_PROTOCOL  End;
+} UDF_DEVICE_PATH;
+
+//
+// C5BD4D42-1A76-4996-8956-73CDA326CD0A
+//
+#define EFI_UDF_DEVICE_PATH_GUID \
+  { 0xC5BD4D42, 0x1A76, 0x4996, \
+    { 0x89, 0x56, 0x73, 0xCD, 0xA3, 0x26, 0xCD, 0x0A } \
+  }
+
+UDF_DEVICE_PATH gUdfDevicePath = {
+  { { MEDIA_DEVICE_PATH, MEDIA_VENDOR_DP,
+      { sizeof (VENDOR_DEVICE_PATH), 0 } },
+    EFI_UDF_DEVICE_PATH_GUID
+  },
+  { END_DEVICE_PATH_TYPE, END_ENTIRE_DEVICE_PATH_SUBTYPE,
+    { sizeof (EFI_DEVICE_PATH_PROTOCOL), 0 }
+  }
+};
+
+EFI_SIMPLE_FILE_SYSTEM_PROTOCOL gUdfSimpleFsOps = {
+  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_REVISION,
+  UdfOpenVolume
+};
+
+/**
+  Test to see if this driver supports ControllerHandle. Any ControllerHandle
+  than contains a BlockIo and DiskIo protocol or a BlockIo2 protocol can be
+  supported.
+
+  @param[in]  This                Protocol instance pointer.
+  @param[in]  ControllerHandle    Handle of device to test.
+  @param[in]  RemainingDevicePath Optional parameter use to pick a specific
+                                  child device to start.
+
+  @retval EFI_SUCCESS         This driver supports this device.
+  @retval EFI_ALREADY_STARTED This driver is already running on this device.
+  @retval other               This driver does not support this device.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfDriverBindingSupported (
+  IN EFI_DRIVER_BINDING_PROTOCOL  *This,
+  IN EFI_HANDLE                   ControllerHandle,
+  IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath
+  )
+{
+  EFI_STATUS                       Status;
+  EFI_DISK_IO_PROTOCOL             *DiskIo;
+  EFI_BLOCK_IO_PROTOCOL            *BlockIo;
+  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL  *SimpleFs;
+
+  Status = gBS->OpenProtocol (
+    ControllerHandle,
+    &gEfiDiskIoProtocolGuid,
+    (VOID **)&DiskIo,
+    This->DriverBindingHandle,
+    ControllerHandle,
+    EFI_OPEN_PROTOCOL_GET_PROTOCOL
+    );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Status = gBS->OpenProtocol (
+    ControllerHandle,
+    &gEfiBlockIoProtocolGuid,
+    (VOID **)&BlockIo,
+    This->DriverBindingHandle,
+    ControllerHandle,
+    EFI_OPEN_PROTOCOL_GET_PROTOCOL
+    );
+  if (EFI_ERROR (Status)) {
+    goto Error_Open_BlockIo;
+  }
+
+  Status = SupportUdfFileSystem (BlockIo, DiskIo);
+  if (EFI_ERROR (Status)) {
+    goto Error_No_Udf_Volume;
+  }
+
+  Status = gBS->OpenProtocol (
+    ControllerHandle,
+    &gEfiSimpleFileSystemProtocolGuid,
+    (VOID **)&SimpleFs,
+    This->DriverBindingHandle,
+    ControllerHandle,
+    EFI_OPEN_PROTOCOL_GET_PROTOCOL
+    );
+  if (!EFI_ERROR (Status)) {
+    gBS->CloseProtocol (
+      ControllerHandle,
+      &gEfiSimpleFileSystemProtocolGuid,
+      This->DriverBindingHandle,
+      ControllerHandle
+      );
+    Status = EFI_ALREADY_STARTED;
+  } else {
+    Status = EFI_SUCCESS;
+  }
+
+  if (EFI_ERROR (Status)) {
+Error_No_Udf_Volume:
+Error_Open_BlockIo:
+    gBS->CloseProtocol (
+      ControllerHandle,
+      &gEfiDiskIoProtocolGuid,
+      This->DriverBindingHandle,
+      ControllerHandle
+      );
+    gBS->CloseProtocol (
+      ControllerHandle,
+      &gEfiBlockIoProtocolGuid,
+      This->DriverBindingHandle,
+      ControllerHandle
+      );
+  }
+
+  return Status;
+}
+
+/**
+  Start this driver on ControllerHandle by opening a Block IO or a Block IO2
+  or both, and Disk IO protocol, reading Device Path, and creating a child
+  handle with a Disk IO and device path protocol.
+
+  @param[in]  This                 Protocol instance pointer.
+  @param[in]  ControllerHandle     Handle of device to bind driver to
+  @param[in]  RemainingDevicePath  Optional parameter use to pick a specific
+                                   child device to start.
+
+  @retval EFI_SUCCESS          This driver is added to ControllerHandle.
+  @retval EFI_ALREADY_STARTED  This driver is already running on
+                               ControllerHandle.
+  @retval other                This driver does not support this device.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfDriverBindingStart (
+  IN EFI_DRIVER_BINDING_PROTOCOL  *This,
+  IN EFI_HANDLE                   ControllerHandle,
+  IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath
+  )
+{
+  EFI_TPL                     OldTpl;
+  EFI_STATUS                  Status;
+  EFI_BLOCK_IO_PROTOCOL       *BlockIo;
+  EFI_DISK_IO_PROTOCOL        *DiskIo;
+  PRIVATE_UDF_SIMPLE_FS_DATA  *PrivFsData;
+
+  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
+
+  Status = gBS->OpenProtocol (
+    ControllerHandle,
+    &gEfiBlockIoProtocolGuid,
+    (VOID **)&BlockIo,
+    This->DriverBindingHandle,
+    ControllerHandle,
+    EFI_OPEN_PROTOCOL_GET_PROTOCOL
+    );
+  if (EFI_ERROR (Status)) {
+    goto Exit;
+  }
+
+  Status = gBS->OpenProtocol (
+    ControllerHandle,
+    &gEfiDiskIoProtocolGuid,
+    (VOID **)&DiskIo,
+    This->DriverBindingHandle,
+    ControllerHandle,
+    EFI_OPEN_PROTOCOL_GET_PROTOCOL
+    );
+  if (EFI_ERROR (Status)) {
+    goto Exit;
+  }
+
+  //
+  // Check if media contains a valid UDF volume.
+  //
+  Status = SupportUdfFileSystem (BlockIo, DiskIo);
+  if (EFI_ERROR (Status)) {
+    goto Exit;
+  }
+
+  PrivFsData =
+    (PRIVATE_UDF_SIMPLE_FS_DATA *)
+    AllocateZeroPool (sizeof (PRIVATE_UDF_SIMPLE_FS_DATA));
+  if (PrivFsData == NULL) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto Exit;
+  }
+
+  //
+  // Create new child handle
+  //
+  PrivFsData->Signature = PRIVATE_UDF_SIMPLE_FS_DATA_SIGNATURE;
+  PrivFsData->BlockIo   = BlockIo;
+  PrivFsData->DiskIo    = DiskIo;
+
+  CopyMem ((VOID *)&PrivFsData->SimpleFs, (VOID *)&gUdfSimpleFsOps,
+           sizeof (EFI_SIMPLE_FILE_SYSTEM_PROTOCOL));
+
+  PrivFsData->DevicePath =
+    DuplicateDevicePath ((EFI_DEVICE_PATH_PROTOCOL *)&gUdfDevicePath);
+
+  //
+  // Install new child handle
+  //
+  Status = gBS->InstallMultipleProtocolInterfaces (
+    &PrivFsData->Handle,
+    &gEfiSimpleFileSystemProtocolGuid,
+    &PrivFsData->SimpleFs,
+    &gEfiDevicePathProtocolGuid,
+    PrivFsData->DevicePath,
+    NULL,
+    NULL
+    );
+
+Exit:
+  gBS->RestoreTPL (OldTpl);
+
+  return Status;
+}
+
+/**
+  Stop this driver on ControllerHandle. Support stopping any child handles
+  created by this driver.
+
+  @param  This              Protocol instance pointer.
+  @param  ControllerHandle  Handle of device to stop driver on
+  @param  NumberOfChildren  Number of Handles in ChildHandleBuffer. If number of
+                            children is zero stop the entire bus driver.
+  @param  ChildHandleBuffer List of Child Handles to Stop.
+
+  @retval EFI_SUCCESS       This driver is removed ControllerHandle
+  @retval other             This driver was not removed from this device
+
+**/
+EFI_STATUS
+EFIAPI
+UdfDriverBindingStop (
+  IN  EFI_DRIVER_BINDING_PROTOCOL   *This,
+  IN  EFI_HANDLE                    ControllerHandle,
+  IN  UINTN                         NumberOfChildren,
+  IN  EFI_HANDLE                    *ChildHandleBuffer
+  )
+{
+  UINTN Index;
+  PRIVATE_UDF_SIMPLE_FS_DATA        *PrivFsData;
+  EFI_STATUS                        Status;
+  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL   *SimpleFs;
+  EFI_DISK_IO_PROTOCOL              *DiskIo;
+  EFI_BLOCK_IO_PROTOCOL              *BlockIo;
+  BOOLEAN                           Done;
+
+  Status = EFI_SUCCESS;
+
+  if (NumberOfChildren == 0) {
+    gBS->CloseProtocol (
+      ControllerHandle,
+      &gEfiDiskIoProtocolGuid,
+      This->DriverBindingHandle,
+      ControllerHandle
+      );
+    goto Exit;
+  }
+
+  Done = TRUE;
+
+  for (Index = 0; Index < NumberOfChildren; Index++) {
+    gBS->OpenProtocol (
+      ChildHandleBuffer[Index],
+      &gEfiSimpleFileSystemProtocolGuid,
+      (VOID **)&SimpleFs,
+      This->DriverBindingHandle,
+      ControllerHandle,
+      EFI_OPEN_PROTOCOL_GET_PROTOCOL
+      );
+
+    PrivFsData = PRIVATE_UDF_SIMPLE_FS_DATA_FROM_THIS (This);
+
+    gBS->CloseProtocol (
+      ControllerHandle,
+      &gEfiDiskIoProtocolGuid,
+      This->DriverBindingHandle,
+      ControllerHandle
+      );
+    gBS->CloseProtocol (
+      ControllerHandle,
+      &gEfiBlockIoProtocolGuid,
+      This->DriverBindingHandle,
+      ControllerHandle
+      );
+
+    Status = gBS->UninstallMultipleProtocolInterfaces (
+      ChildHandleBuffer[Index],
+      &gEfiSimpleFileSystemProtocolGuid,
+      &PrivFsData->SimpleFs,
+      &gEfiDevicePathProtocolGuid,
+      PrivFsData->DevicePath,
+      NULL
+      );
+    if (EFI_ERROR (Status)) {
+      gBS->OpenProtocol (
+        ControllerHandle,
+        &gEfiDiskIoProtocolGuid,
+        (VOID **)&DiskIo,
+        This->DriverBindingHandle,
+        ChildHandleBuffer[Index],
+        EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER
+        );
+      gBS->OpenProtocol (
+        ControllerHandle,
+        &gEfiBlockIoProtocolGuid,
+        (VOID **)&BlockIo,
+        This->DriverBindingHandle,
+        ChildHandleBuffer[Index],
+        EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER
+        );
+    } else {
+      FreePool ((VOID *)PrivFsData->DevicePath);
+
+      if (PrivFsData->OpenFiles) {
+        CleanupVolumeInformation (&PrivFsData->Volume);
+      }
+
+      FreePool ((VOID *)PrivFsData);
+    }
+
+    if (EFI_ERROR (Status)) {
+      Done = FALSE;
+    }
+  }
+
+  if (!Done) {
+    Status = EFI_DEVICE_ERROR;
+  }
+
+Exit:
+  return Status;
+}
+
+/**
+  The user Entry Point for UDF file system driver. The user code starts with
+  this function.
+
+  @param[in] ImageHandle    The firmware allocated handle for the EFI image.
+  @param[in] SystemTable    A pointer to the EFI System Table.
+
+  @retval EFI_SUCCESS       The entry point is executed successfully.
+  @retval other             Some error occurs when executing this entry point.
+
+**/
+EFI_STATUS
+EFIAPI
+InitializeUdf (
+  IN EFI_HANDLE           ImageHandle,
+  IN EFI_SYSTEM_TABLE     *SystemTable
+  )
+{
+  EFI_STATUS              Status;
+
+  Status = EfiLibInstallDriverBindingComponentName2 (
+    ImageHandle,
+    SystemTable,
+    &gUdfDriverBinding,
+    ImageHandle,
+    &gUdfComponentName,
+    &gUdfComponentName2
+    );
+  ASSERT_EFI_ERROR (Status);
+
+  return Status;
+}
diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/Udf.h b/MdeModulePkg/Universal/Disk/UdfDxe/Udf.h
new file mode 100644
index 0000000000..37d7c613e1
--- /dev/null
+++ b/MdeModulePkg/Universal/Disk/UdfDxe/Udf.h
@@ -0,0 +1,1243 @@
+/** @file
+  UDF/ECMA-167 file system driver.
+
+  Copyright (C) 2014-2017 Paulo Alcantara <pcacjr@zytor.com>
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#ifndef _UDF_H_
+#define _UDF_H_
+
+#include <Uefi.h>
+
+#include <Protocol/BlockIo.h>
+#include <Protocol/ComponentName.h>
+#include <Protocol/DevicePath.h>
+#include <Protocol/DriverBinding.h>
+#include <Protocol/DiskIo.h>
+#include <Protocol/SimpleFileSystem.h>
+
+#include <Guid/FileInfo.h>
+#include <Guid/FileSystemInfo.h>
+#include <Guid/FileSystemVolumeLabelInfo.h>
+
+#include <Library/DebugLib.h>
+#include <Library/UefiDriverEntryPoint.h>
+#include <Library/BaseLib.h>
+#include <Library/UefiLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/DevicePathLib.h>
+
+#define UDF_LOGICAL_SECTOR_SHIFT        11
+#define UDF_LOGICAL_SECTOR_SIZE         ((UINT64)(1 << UDF_LOGICAL_SECTOR_SHIFT))
+#define UDF_VRS_START_OFFSET            ((UINT64)(16 << UDF_LOGICAL_SECTOR_SHIFT))
+#define UDF_STANDARD_IDENTIFIER_LENGTH  5
+#define UDF_CDROM_VOLUME_IDENTIFIER     "CD001"
+
+#define UDF_DEFAULT_LV_NUM              0
+
+#define _GET_TAG_ID(_Pointer) \
+  (((UDF_DESCRIPTOR_TAG *)(_Pointer))->TagIdentifier)
+
+#define IS_PVD(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 1))
+#define IS_AVDP(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 2))
+#define IS_PD(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 5))
+#define IS_LVD(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 6))
+#define IS_TD(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 8))
+#define IS_FSD(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 256))
+#define IS_FE(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 261))
+#define IS_EFE(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 266))
+#define IS_FID(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 257))
+#define IS_AED(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 258))
+#define IS_LVID(_Pointer) \
+  ((BOOLEAN)(_GET_TAG_ID (_Pointer) == 9))
+
+#define _GET_FILETYPE(_Pointer) \
+  (IS_FE (_Pointer) ? \
+   (((UDF_FILE_ENTRY *)(_Pointer))->IcbTag.FileType) \
+   : \
+   (((UDF_EXTENDED_FILE_ENTRY *)(_Pointer))->IcbTag.FileType))
+
+#define IS_FE_DIRECTORY(_Pointer) \
+  ((BOOLEAN)(_GET_FILETYPE (_Pointer) == 4))
+#define IS_FE_STANDARD_FILE(_Pointer) \
+  ((BOOLEAN)(_GET_FILETYPE (_Pointer) == 5))
+#define IS_FE_SYMLINK(_Pointer) \
+  ((BOOLEAN)(_GET_FILETYPE (_Pointer) == 12))
+
+#define HIDDEN_FILE     (1 << 0)
+#define DIRECTORY_FILE  (1 << 1)
+#define DELETED_FILE    (1 << 2)
+#define PARENT_FILE     (1 << 3)
+
+#define _GET_FILE_CHARS(_Pointer) \
+  (((UDF_FILE_IDENTIFIER_DESCRIPTOR *)(_Pointer))->FileCharacteristics)
+
+#define IS_FID_HIDDEN_FILE(_Pointer) \
+  ((BOOLEAN)(_GET_FILE_CHARS (_Pointer) & HIDDEN_FILE))
+#define IS_FID_DIRECTORY_FILE(_Pointer) \
+  ((BOOLEAN)(_GET_FILE_CHARS (_Pointer) & DIRECTORY_FILE))
+#define IS_FID_DELETED_FILE(_Pointer) \
+  ((BOOLEAN)(_GET_FILE_CHARS (_Pointer) & DELETED_FILE))
+#define IS_FID_PARENT_FILE(_Pointer) \
+  ((BOOLEAN)(_GET_FILE_CHARS (_Pointer) & PARENT_FILE))
+#define IS_FID_NORMAL_FILE(_Pointer) \
+  ((BOOLEAN)(!IS_FID_DIRECTORY_FILE (_Pointer) && \
+	     !IS_FID_PARENT_FILE (_Pointer)))
+
+typedef enum {
+  SHORT_ADS_SEQUENCE,
+  LONG_ADS_SEQUENCE,
+  EXTENDED_ADS_SEQUENCE,
+  INLINE_DATA
+} UDF_FE_RECORDING_FLAGS;
+
+#define GET_FE_RECORDING_FLAGS(_Fe) \
+  ((UDF_FE_RECORDING_FLAGS)((UDF_ICB_TAG *)( \
+			      (UINT8 *)(_Fe) + \
+			      sizeof (UDF_DESCRIPTOR_TAG)))->Flags & 0x07)
+
+typedef enum {
+  EXTENT_RECORDED_AND_ALLOCATED,
+  EXTENT_NOT_RECORDED_BUT_ALLOCATED,
+  EXTENT_NOT_RECORDED_NOT_ALLOCATED,
+  EXTENT_IS_NEXT_EXTENT,
+} UDF_EXTENT_FLAGS;
+
+#define AD_LENGTH(_RecFlags) \
+  ((_RecFlags) == SHORT_ADS_SEQUENCE ? \
+   ((UINT64)(sizeof (UDF_SHORT_ALLOCATION_DESCRIPTOR))) : \
+   ((UINT64)(sizeof (UDF_LONG_ALLOCATION_DESCRIPTOR))))
+
+#define GET_EXTENT_FLAGS(_RecFlags, _Ad) \
+  ((_RecFlags) == SHORT_ADS_SEQUENCE ? \
+   ((UDF_EXTENT_FLAGS)((((UDF_SHORT_ALLOCATION_DESCRIPTOR *)(_Ad))->ExtentLength >> \
+			30) & 0x3)) : \
+   ((UDF_EXTENT_FLAGS)((((UDF_LONG_ALLOCATION_DESCRIPTOR *)(_Ad))->ExtentLength >> \
+			30) & 0x3)))
+
+#define GET_EXTENT_LENGTH(_RecFlags, _Ad) \
+  ((_RecFlags) == SHORT_ADS_SEQUENCE ? \
+   ((UINT32)((((UDF_SHORT_ALLOCATION_DESCRIPTOR *)(_Ad))->ExtentLength & \
+	      ~0xC0000000UL))) : \
+   ((UINT32)((((UDF_LONG_ALLOCATION_DESCRIPTOR *)(_Ad))->ExtentLength & \
+	      ~0xC0000000UL))))
+
+#define UDF_FILENAME_LENGTH  128
+#define UDF_PATH_LENGTH      512
+
+#define GET_FID_FROM_ADS(_Data, _Offs) \
+  ((UDF_FILE_IDENTIFIER_DESCRIPTOR *)((UINT8 *)(_Data) + (_Offs)))
+
+#define IS_VALID_COMPRESSION_ID(_CompId) \
+  ((BOOLEAN)((_CompId) == 8 || (_CompId) == 16))
+
+#define LV_BLOCK_SIZE(_Vol, _LvNum) \
+  (_Vol)->LogicalVolDescs[(_LvNum)]->LogicalBlockSize
+
+#define UDF_STANDARD_IDENTIFIER_LENGTH   5
+
+#pragma pack(1)
+
+typedef struct {
+  UINT8 StandardIdentifier[UDF_STANDARD_IDENTIFIER_LENGTH];
+} UDF_STANDARD_IDENTIFIER;
+
+#pragma pack()
+
+enum {
+  BEA_IDENTIFIER,
+  VSD_IDENTIFIER,
+  TEA_IDENTIFIER,
+  NR_STANDARD_IDENTIFIERS,
+};
+
+typedef enum {
+  READ_FILE_GET_FILESIZE,
+  READ_FILE_ALLOCATE_AND_READ,
+  READ_FILE_SEEK_AND_READ,
+} UDF_READ_FILE_FLAGS;
+
+typedef struct {
+  VOID                 *FileData;
+  UDF_READ_FILE_FLAGS  Flags;
+  UINT64               FileDataSize;
+  UINT64               FilePosition;
+  UINT64               FileSize;
+  UINT64               ReadLength;
+} UDF_READ_FILE_INFO;
+
+#pragma pack(1)
+
+typedef struct {
+  UINT16               TagIdentifier;
+  UINT16               DescriptorVersion;
+  UINT8                TagChecksum;
+  UINT8                Reserved;
+  UINT16               TagSerialNumber;
+  UINT16               DescriptorCRC;
+  UINT16               DescriptorCRCLength;
+  UINT32               TagLocation;
+} UDF_DESCRIPTOR_TAG;
+
+typedef struct {
+  UINT8           CharacterSetType;
+  UINT8           CharacterSetInfo[63];
+} UDF_CHAR_SPEC;
+
+typedef struct {
+  UINT8           Flags;
+  UINT8           Identifier[23];
+  UINT8           IdentifierSuffix[8];
+} UDF_ENTITY_ID;
+
+typedef struct {
+  UINT16          TypeAndTimezone;
+  INT16           Year;
+  UINT8           Month;
+  UINT8           Day;
+  UINT8           Hour;
+  UINT8           Minute;
+  UINT8           Second;
+  UINT8           Centiseconds;
+  UINT8           HundredsOfMicroseconds;
+  UINT8           Microseconds;
+} UDF_TIMESTAMP;
+
+typedef struct {
+  UINT32          ExtentLength;
+  UINT32          ExtentLocation;
+} UDF_EXTENT_AD;
+
+typedef struct {
+  UINT32        LogicalBlockNumber;
+  UINT16        PartitionReferenceNumber;
+} UDF_LB_ADDR;
+
+typedef struct {
+  UINT32                           ExtentLength;
+  UDF_LB_ADDR                      ExtentLocation;
+  UINT8                            ImplementationUse[6];
+} UDF_LONG_ALLOCATION_DESCRIPTOR;
+
+typedef struct {
+  UDF_DESCRIPTOR_TAG                 DescriptorTag;
+  UINT32                             PrevAllocationExtentDescriptor;
+  UINT32                             LengthOfAllocationDescriptors;
+} UDF_ALLOCATION_EXTENT_DESCRIPTOR;
+
+typedef struct {
+  UINT8                   StructureType;
+  UINT8                   StandardIdentifier[UDF_STANDARD_IDENTIFIER_LENGTH];
+  UINT8                   StructureVersion;
+  UINT8                   Reserved;
+  UINT8                   StructureData[2040];
+} UDF_VOLUME_DESCRIPTOR;
+
+typedef struct {
+  UDF_DESCRIPTOR_TAG                     DescriptorTag;
+  UDF_EXTENT_AD                          MainVolumeDescriptorSequenceExtent;
+  UDF_EXTENT_AD                          ReserveVolumeDescriptorSequenceExtent;
+  UINT8                                  Reserved[480];
+} UDF_ANCHOR_VOLUME_DESCRIPTOR_POINTER;
+
+typedef struct {
+  UDF_DESCRIPTOR_TAG         DescriptorTag;
+  UINT32                     VolumeDescriptorSequenceNumber;
+  UINT16                     PartitionFlags;
+  UINT16                     PartitionNumber;
+  UDF_ENTITY_ID              PartitionContents;
+  UINT8                      PartitionContentsUse[128];
+  UINT32                     AccessType;
+  UINT32                     PartitionStartingLocation;
+  UINT32                     PartitionLength;
+  UDF_ENTITY_ID              ImplementationIdentifier;
+  UINT8                      ImplementationUse[128];
+  UINT8                      Reserved[156];
+} UDF_PARTITION_DESCRIPTOR;
+
+typedef struct {
+  UDF_DESCRIPTOR_TAG              DescriptorTag;
+  UINT32                          VolumeDescriptorSequenceNumber;
+  UDF_CHAR_SPEC                   DescriptorCharacterSet;
+  UINT8                           LogicalVolumeIdentifier[128];
+  UINT32                          LogicalBlockSize;
+  UDF_ENTITY_ID                   DomainIdentifier;
+  UDF_LONG_ALLOCATION_DESCRIPTOR  LogicalVolumeContentsUse;
+  UINT32                          MapTableLength;
+  UINT32                          NumberOfPartitionMaps;
+  UDF_ENTITY_ID                   ImplementationIdentifier;
+  UINT8                           ImplementationUse[128];
+  UDF_EXTENT_AD                   IntegritySequenceExtent;
+  UINT8                           PartitionMaps[6];
+} UDF_LOGICAL_VOLUME_DESCRIPTOR;
+
+typedef struct {
+  UDF_DESCRIPTOR_TAG             DescriptorTag;
+  UDF_TIMESTAMP                  RecordingDateTime;
+  UINT32                         IntegrityType;
+  UDF_EXTENT_AD                  NextIntegrityExtent;
+  UINT8                          LogicalVolumeContentsUse[32];
+  UINT32                         NumberOfPartitions;
+  UINT32                         LengthOfImplementationUse;
+  UINT8                          Data[0];
+} UDF_LOGICAL_VOLUME_INTEGRITY;
+
+typedef struct {
+  UDF_DESCRIPTOR_TAG              DescriptorTag;
+  UDF_TIMESTAMP                   RecordingDateAndTime;
+  UINT16                          InterchangeLevel;
+  UINT16                          MaximumInterchangeLevel;
+  UINT32                          CharacterSetList;
+  UINT32                          MaximumCharacterSetList;
+  UINT32                          FileSetNumber;
+  UINT32                          FileSetDescriptorNumber;
+  UDF_CHAR_SPEC                   LogicalVolumeIdentifierCharacterSet;
+  UINT8                           LogicalVolumeIdentifier[128];
+  UDF_CHAR_SPEC                   FileSetCharacterSet;
+  UINT8                           FileSetIdentifier[32];
+  UINT8                           CopyrightFileIdentifier[32];
+  UINT8                           AbstractFileIdentifier[32];
+  UDF_LONG_ALLOCATION_DESCRIPTOR  RootDirectoryIcb;
+  UDF_ENTITY_ID                   DomainIdentifier;
+  UDF_LONG_ALLOCATION_DESCRIPTOR  NextExtent;
+  UDF_LONG_ALLOCATION_DESCRIPTOR  SystemStreamDirectoryIcb;
+  UINT8                           Reserved[32];
+} UDF_FILE_SET_DESCRIPTOR;
+
+typedef struct {
+  UINT32                            ExtentLength;
+  UINT32                            ExtentPosition;
+} UDF_SHORT_ALLOCATION_DESCRIPTOR;
+
+typedef struct {
+  UDF_DESCRIPTOR_TAG               DescriptorTag;
+  UINT16                           FileVersionNumber;
+  UINT8                            FileCharacteristics;
+  UINT8                            LengthOfFileIdentifier;
+  UDF_LONG_ALLOCATION_DESCRIPTOR   Icb;
+  UINT16                           LengthOfImplementationUse;
+  UINT8                            Data[0];
+} UDF_FILE_IDENTIFIER_DESCRIPTOR;
+
+typedef struct {
+  UINT32        PriorRecordNumberOfDirectEntries;
+  UINT16        StrategyType;
+  UINT16        StrategyParameter;
+  UINT16        MaximumNumberOfEntries;
+  UINT8         Reserved;
+  UINT8         FileType;
+  UDF_LB_ADDR   ParentIcbLocation;
+  UINT16        Flags;
+} UDF_ICB_TAG;
+
+typedef struct {
+  UDF_DESCRIPTOR_TAG              DescriptorTag;
+  UDF_ICB_TAG                     IcbTag;
+  UINT32                          Uid;
+  UINT32                          Gid;
+  UINT32                          Permissions;
+  UINT16                          FileLinkCount;
+  UINT8                           RecordFormat;
+  UINT8                           RecordDisplayAttributes;
+  UINT32                          RecordLength;
+  UINT64                          InformationLength;
+  UINT64                          LogicalBlocksRecorded;
+  UDF_TIMESTAMP                   AccessTime;
+  UDF_TIMESTAMP                   ModificationTime;
+  UDF_TIMESTAMP                   AttributeTime;
+  UINT32                          CheckPoint;
+  UDF_LONG_ALLOCATION_DESCRIPTOR  ExtendedAttributeIcb;
+  UDF_ENTITY_ID                   ImplementationIdentifier;
+  UINT64                          UniqueId;
+  UINT32                          LengthOfExtendedAttributes;
+  UINT32                          LengthOfAllocationDescriptors;
+  UINT8                           Data[0]; // L_EA + L_AD
+} UDF_FILE_ENTRY;
+
+typedef struct {
+  UDF_DESCRIPTOR_TAG              DescriptorTag;
+  UDF_ICB_TAG                     IcbTag;
+  UINT32                          Uid;
+  UINT32                          Gid;
+  UINT32                          Permissions;
+  UINT16                          FileLinkCount;
+  UINT8                           RecordFormat;
+  UINT8                           RecordDisplayAttributes;
+  UINT32                          RecordLength;
+  UINT64                          InformationLength;
+  UINT64                          ObjectSize;
+  UINT64                          LogicalBlocksRecorded;
+  UDF_TIMESTAMP                   AccessTime;
+  UDF_TIMESTAMP                   ModificationTime;
+  UDF_TIMESTAMP                   CreationTime;
+  UDF_TIMESTAMP                   AttributeTime;
+  UINT32                          CheckPoint;
+  UINT32                          Reserved;
+  UDF_LONG_ALLOCATION_DESCRIPTOR  ExtendedAttributeIcb;
+  UDF_LONG_ALLOCATION_DESCRIPTOR  StreamDirectoryIcb;
+  UDF_ENTITY_ID                   ImplementationIdentifier;
+  UINT64                          UniqueId;
+  UINT32                          LengthOfExtendedAttributes;
+  UINT32                          LengthOfAllocationDescriptors;
+  UINT8                           Data[0]; // L_EA + L_AD
+} UDF_EXTENDED_FILE_ENTRY;
+
+typedef struct {
+  UINT8                ComponentType;
+  UINT8                LengthOfComponentIdentifier;
+  UINT16               ComponentFileVersionNumber;
+  UINT8                ComponentIdentifier[0];
+} UDF_PATH_COMPONENT;
+
+#pragma pack()
+
+//
+// UDF filesystem driver's private data
+//
+typedef struct {
+  UDF_LOGICAL_VOLUME_DESCRIPTOR  **LogicalVolDescs;
+  UINTN                          LogicalVolDescsNo;
+  UDF_PARTITION_DESCRIPTOR       **PartitionDescs;
+  UINTN                          PartitionDescsNo;
+  UDF_FILE_SET_DESCRIPTOR        **FileSetDescs;
+  UINTN                          FileSetDescsNo;
+  UINTN                          FileEntrySize;
+} UDF_VOLUME_INFO;
+
+typedef struct {
+  VOID                            *FileEntry;
+  UDF_FILE_IDENTIFIER_DESCRIPTOR  *FileIdentifierDesc;
+} UDF_FILE_INFO;
+
+typedef struct {
+  VOID                      *DirectoryData;
+  UINT64                    DirectoryLength;
+  UINT64                    FidOffset;
+} UDF_READ_DIRECTORY_INFO;
+
+#define PRIVATE_UDF_FILE_DATA_SIGNATURE SIGNATURE_32 ('U', 'd', 'f', 'f')
+
+#define PRIVATE_UDF_FILE_DATA_FROM_THIS(a) \
+  CR ( \
+      a, \
+      PRIVATE_UDF_FILE_DATA, \
+      FileIo, \
+      PRIVATE_UDF_FILE_DATA_SIGNATURE \
+      )
+
+typedef struct {
+  UINTN                            Signature;
+  BOOLEAN                          IsRootDirectory;
+  UDF_FILE_INFO                    *Root;
+  UDF_FILE_INFO                    File;
+  UDF_READ_DIRECTORY_INFO          ReadDirInfo;
+  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL  *SimpleFs;
+  EFI_FILE_PROTOCOL                FileIo;
+  CHAR16                           AbsoluteFileName[UDF_PATH_LENGTH];
+  CHAR16                           FileName[UDF_FILENAME_LENGTH];
+  UINT64                           FileSize;
+  UINT64                           FilePosition;
+} PRIVATE_UDF_FILE_DATA;
+
+#define PRIVATE_UDF_SIMPLE_FS_DATA_SIGNATURE SIGNATURE_32 ('U', 'd', 'f', 's')
+
+#define PRIVATE_UDF_SIMPLE_FS_DATA_FROM_THIS(a) \
+  CR ( \
+      a, \
+      PRIVATE_UDF_SIMPLE_FS_DATA, \
+      SimpleFs, \
+      PRIVATE_UDF_SIMPLE_FS_DATA_SIGNATURE \
+      )
+
+typedef struct {
+  UINTN                            Signature;
+  EFI_BLOCK_IO_PROTOCOL            *BlockIo;
+  EFI_DISK_IO_PROTOCOL             *DiskIo;
+  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL  SimpleFs;
+  EFI_DEVICE_PATH_PROTOCOL         *DevicePath;
+  UDF_VOLUME_INFO                  Volume;
+  UDF_FILE_INFO                    Root;
+  UINTN                            OpenFiles;
+  EFI_HANDLE                       Handle;
+} PRIVATE_UDF_SIMPLE_FS_DATA;
+
+//
+// Global Variables
+//
+extern EFI_DRIVER_BINDING_PROTOCOL   gUdfDriverBinding;
+extern EFI_COMPONENT_NAME_PROTOCOL   gUdfComponentName;
+extern EFI_COMPONENT_NAME2_PROTOCOL  gUdfComponentName2;
+
+//
+// Function Prototypes
+//
+
+/**
+  Open the root directory on a volume.
+
+  @param  This Protocol instance pointer.
+  @param  Root Returns an Open file handle for the root directory
+
+  @retval EFI_SUCCESS          The device was opened.
+  @retval EFI_UNSUPPORTED      This volume does not support the file system.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_ACCESS_DENIED    The service denied access to the file.
+  @retval EFI_OUT_OF_RESOURCES The volume was not opened due to lack of resources.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfOpenVolume (
+  IN   EFI_SIMPLE_FILE_SYSTEM_PROTOCOL  *This,
+  OUT  EFI_FILE_PROTOCOL                **Root
+  );
+
+/**
+  Opens a new file relative to the source file's location.
+
+  @param  This       The protocol instance pointer.
+  @param  NewHandle  Returns File Handle for FileName.
+  @param  FileName   Null terminated string. "\", ".", and ".." are supported.
+  @param  OpenMode   Open mode for file.
+  @param  Attributes Only used for EFI_FILE_MODE_CREATE.
+
+  @retval EFI_SUCCESS          The device was opened.
+  @retval EFI_NOT_FOUND        The specified file could not be found on the device.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_MEDIA_CHANGED    The media has changed.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_ACCESS_DENIED    The service denied access to the file.
+  @retval EFI_OUT_OF_RESOURCES The volume was not opened due to lack of resources.
+  @retval EFI_VOLUME_FULL      The volume is full.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfOpen (
+  IN   EFI_FILE_PROTOCOL  *This,
+  OUT  EFI_FILE_PROTOCOL  **NewHandle,
+  IN   CHAR16             *FileName,
+  IN   UINT64             OpenMode,
+  IN   UINT64             Attributes
+  );
+
+/**
+  Read data from the file.
+
+  @param  This       Protocol instance pointer.
+  @param  BufferSize On input size of buffer, on output amount of data in buffer.
+  @param  Buffer     The buffer in which data is read.
+
+  @retval EFI_SUCCESS          Data was read.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_BUFFER_TO_SMALL  BufferSize is too small. BufferSize contains required size.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfRead (
+  IN      EFI_FILE_PROTOCOL  *This,
+  IN OUT  UINTN              *BufferSize,
+  OUT     VOID               *Buffer
+  );
+
+/**
+  Close the file handle.
+
+  @param  This Protocol instance pointer.
+
+  @retval EFI_SUCCESS The file was closed.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfClose (
+  IN EFI_FILE_PROTOCOL *This
+  );
+
+/**
+  Close and delete the file handle.
+
+  @param  This Protocol instance pointer.
+
+  @retval EFI_SUCCESS              The file was closed and deleted.
+  @retval EFI_WARN_DELETE_FAILURE  The handle was closed but the file was not
+                                   deleted.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfDelete (
+  IN EFI_FILE_PROTOCOL  *This
+  );
+
+/**
+  Write data to a file.
+
+  @param  This       Protocol instance pointer.
+  @param  BufferSize On input size of buffer, on output amount of data in buffer.
+  @param  Buffer     The buffer in which data to write.
+
+  @retval EFI_SUCCESS          Data was written.
+  @retval EFI_UNSUPPORTED      Writes to Open directory are not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_DEVICE_ERROR     An attempt was made to write to a deleted file.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_WRITE_PROTECTED  The device is write protected.
+  @retval EFI_ACCESS_DENIED    The file was open for read only.
+  @retval EFI_VOLUME_FULL      The volume is full.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfWrite (
+  IN      EFI_FILE_PROTOCOL  *This,
+  IN OUT  UINTN              *BufferSize,
+  IN      VOID               *Buffer
+  );
+
+/**
+  Get file's current position.
+
+  @param  This      Protocol instance pointer.
+  @param  Position  Byte position from the start of the file.
+
+  @retval EFI_SUCCESS     Position was updated.
+  @retval EFI_UNSUPPORTED Seek request for directories is not valid.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfGetPosition (
+  IN   EFI_FILE_PROTOCOL  *This,
+  OUT  UINT64             *Position
+  );
+
+/**
+  Set file's current position.
+
+  @param  This      Protocol instance pointer.
+  @param  Position  Byte position from the start of the file.
+
+  @retval EFI_SUCCESS      Position was updated.
+  @retval EFI_UNSUPPORTED  Seek request for non-zero is not valid on open.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfSetPosition (
+  IN EFI_FILE_PROTOCOL  *This,
+  IN UINT64             Position
+  );
+
+/**
+  Get information about a file.
+
+  @param  This            Protocol instance pointer.
+  @param  InformationType Type of information to return in Buffer.
+  @param  BufferSize      On input size of buffer, on output amount of data in buffer.
+  @param  Buffer          The buffer to return data.
+
+  @retval EFI_SUCCESS          Data was returned.
+  @retval EFI_UNSUPPORTED      InformationType is not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_WRITE_PROTECTED  The device is write protected.
+  @retval EFI_ACCESS_DENIED    The file was open for read only.
+  @retval EFI_BUFFER_TOO_SMALL Buffer was too small; required size returned in BufferSize.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfGetInfo (
+  IN      EFI_FILE_PROTOCOL  *This,
+  IN      EFI_GUID           *InformationType,
+  IN OUT  UINTN              *BufferSize,
+  OUT     VOID               *Buffer
+  );
+
+/**
+  Set information about a file.
+
+  @param  File            Protocol instance pointer.
+  @param  InformationType Type of information in Buffer.
+  @param  BufferSize      Size of buffer.
+  @param  Buffer          The data to write.
+
+  @retval EFI_SUCCESS          Data was set.
+  @retval EFI_UNSUPPORTED      InformationType is not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_WRITE_PROTECTED  The device is write protected.
+  @retval EFI_ACCESS_DENIED    The file was open for read only.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfSetInfo (
+  IN EFI_FILE_PROTOCOL  *This,
+  IN EFI_GUID           *InformationType,
+  IN UINTN              BufferSize,
+  IN VOID               *Buffer
+  );
+
+/**
+  Flush data back for the file handle.
+
+  @param  This Protocol instance pointer.
+
+  @retval EFI_SUCCESS          Data was flushed.
+  @retval EFI_UNSUPPORTED      Writes to Open directory are not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_WRITE_PROTECTED  The device is write protected.
+  @retval EFI_ACCESS_DENIED    The file was open for read only.
+  @retval EFI_VOLUME_FULL      The volume is full.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfFlush (
+  IN EFI_FILE_PROTOCOL *This
+  );
+
+/**
+  Check if medium contains an UDF file system.
+
+  @param[in]   BlockIo  BlockIo interface.
+  @param[in]   DiskIo   DiskIo interface.
+
+  @retval EFI_SUCCESS          UDF file system found.
+  @retval EFI_UNSUPPORTED      UDF file system not found.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The scan was not successful due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+SupportUdfFileSystem (
+  IN  EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN  EFI_DISK_IO_PROTOCOL   *DiskIo
+  );
+
+/**
+  Read volume information on a medium which contains a valid UDF file system.
+
+  @param[in]   BlockIo  BlockIo interface.
+  @param[in]   DiskIo   DiskIo interface.
+  @param[out]  Volume   UDF volume information structure.
+
+  @retval EFI_SUCCESS          Volume information read.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The volume was not read due to lack of resources.
+
+**/
+EFI_STATUS
+ReadUdfVolumeInformation (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  OUT  UDF_VOLUME_INFO        *Volume
+  );
+
+/**
+  Find the root directory on an UDF volume.
+
+  @param[in]   BlockIo  BlockIo interface.
+  @param[in]   DiskIo   DiskIo interface.
+  @param[in]   Volume   UDF volume information structure.
+  @param[out]  File     Root directory file.
+
+  @retval EFI_SUCCESS          Root directory found.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The root directory was not found due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+FindRootDirectory (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  IN   UDF_VOLUME_INFO        *Volume,
+  OUT  UDF_FILE_INFO          *File
+  );
+
+/**
+  Find either a File Entry or a Extended File Entry from a given ICB.
+
+  @param[in]   BlockIo    BlockIo interface.
+  @param[in]   DiskIo     DiskIo interface.
+  @param[in]   Volume     UDF volume information structure.
+  @param[in]   Icb        ICB of the FID.
+  @param[out]  FileEntry  File Entry or Extended File Entry.
+
+  @retval EFI_SUCCESS          File Entry or Extended File Entry found.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The FE/EFE entry was not found due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+FindFileEntry (
+  IN   EFI_BLOCK_IO_PROTOCOL           *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL            *DiskIo,
+  IN   UDF_VOLUME_INFO                 *Volume,
+  IN   UDF_LONG_ALLOCATION_DESCRIPTOR  *Icb,
+  OUT  VOID                            **FileEntry
+  );
+
+/**
+  Find a file given its absolute path on an UDF volume.
+
+  @param[in]   BlockIo   BlockIo interface.
+  @param[in]   DiskIo    DiskIo interface.
+  @param[in]   Volume    UDF volume information structure.
+  @param[in]   FilePath  File's absolute path.
+  @param[in]   Root      Root directory file.
+  @param[in]   Parent    Parent directory file.
+  @param[out]  File      Found file.
+
+  @retval EFI_SUCCESS          @p FilePath was found.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The @p FilePath file was not found due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+FindFile (
+  IN   EFI_BLOCK_IO_PROTOCOL           *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL            *DiskIo,
+  IN   UDF_VOLUME_INFO                 *Volume,
+  IN   CHAR16                          *FilePath,
+  IN   UDF_FILE_INFO                   *Root,
+  IN   UDF_FILE_INFO                   *Parent,
+  IN   UDF_LONG_ALLOCATION_DESCRIPTOR  *Icb,
+  OUT  UDF_FILE_INFO                   *File
+  );
+
+/**
+  Read a directory entry at a time on an UDF volume.
+
+  @param[in]      BlockIo        BlockIo interface.
+  @param[in]      DiskIo         DiskIo interface.
+  @param[in]      Volume         UDF volume information structure.
+  @param[in]      ParentIcb      ICB of the parent file.
+  @param[in]      FileEntryData  FE/EFE of the parent file.
+  @param[in out]  ReadDirInfo    Next read directory listing structure
+                                 information.
+  @param[out]     FoundFid       File Identifier Descriptor pointer.
+
+  @retval EFI_SUCCESS          Directory entry read.
+  @retval EFI_UNSUPPORTED      Extended Allocation Descriptors not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The directory entry was not read due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+ReadDirectoryEntry (
+  IN      EFI_BLOCK_IO_PROTOCOL           *BlockIo,
+  IN      EFI_DISK_IO_PROTOCOL            *DiskIo,
+  IN      UDF_VOLUME_INFO                 *Volume,
+  IN      UDF_LONG_ALLOCATION_DESCRIPTOR  *ParentIcb,
+  IN      VOID                            *FileEntryData,
+  IN OUT  UDF_READ_DIRECTORY_INFO         *ReadDirInfo,
+  OUT     UDF_FILE_IDENTIFIER_DESCRIPTOR  **FoundFid
+  );
+
+/**
+  Get a filename (encoded in OSTA-compressed format) from a File Identifier
+  Descriptor on an UDF volume.
+
+  @param[in]   FileIdentifierDesc  File Identifier Descriptor pointer.
+  @param[out]  FileName            Decoded filename.
+
+  @retval EFI_SUCCESS           Filename decoded and read.
+  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
+**/
+EFI_STATUS
+GetFileNameFromFid (
+  IN   UDF_FILE_IDENTIFIER_DESCRIPTOR  *FileIdentifierDesc,
+  OUT  CHAR16                          *FileName
+  );
+
+/**
+  Resolve a symlink file on an UDF volume.
+
+  @param[in]   BlockIo        BlockIo interface.
+  @param[in]   DiskIo         DiskIo interface.
+  @param[in]   Volume         UDF volume information structure.
+  @param[in]   Parent         Parent file.
+  @param[in]   FileEntryData  FE/EFE structure pointer.
+  @param[out]  File           Resolved file.
+
+  @retval EFI_SUCCESS          Symlink file resolved.
+  @retval EFI_UNSUPPORTED      Extended Allocation Descriptors not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The symlink file was not resolved due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+ResolveSymlink (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  IN   UDF_VOLUME_INFO        *Volume,
+  IN   UDF_FILE_INFO          *Parent,
+  IN   VOID                   *FileEntryData,
+  OUT  UDF_FILE_INFO          *File
+  );
+
+/**
+  Clean up in-memory UDF volume information.
+
+  @param[in] Volume Volume information pointer.
+
+**/
+VOID
+CleanupVolumeInformation (
+  IN UDF_VOLUME_INFO *Volume
+  );
+
+/**
+  Clean up in-memory UDF file information.
+
+  @param[in] File File information pointer.
+
+**/
+VOID
+CleanupFileInformation (
+  IN UDF_FILE_INFO *File
+  );
+
+/**
+  Find a file from its absolute path on an UDF volume.
+
+  @param[in]   BlockIo  BlockIo interface.
+  @param[in]   DiskIo   DiskIo interface.
+  @param[in]   Volume   UDF volume information structure.
+  @param[in]   File     File information structure.
+  @param[out]  Size     Size of the file.
+
+  @retval EFI_SUCCESS          File size calculated and set in @p Size.
+  @retval EFI_UNSUPPORTED      Extended Allocation Descriptors not supported.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The file size was not calculated due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+GetFileSize (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  IN   UDF_VOLUME_INFO        *Volume,
+  IN   UDF_FILE_INFO          *File,
+  OUT  UINT64                 *Size
+  );
+
+/**
+  Set information about a file on an UDF volume.
+
+  @param[in]      File        File pointer.
+  @param[in]      FileSize    Size of the file.
+  @param[in]      FileName    Filename of the file.
+  @param[in out]  BufferSize  Size of the returned file infomation.
+  @param[out]     Buffer      Data of the returned file information.
+
+  @retval EFI_SUCCESS          File information set.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The file information was not set due to lack of
+                               resources.
+
+**/
+EFI_STATUS
+SetFileInfo (
+  IN      UDF_FILE_INFO  *File,
+  IN      UINT64         FileSize,
+  IN      CHAR16         *FileName,
+  IN OUT  UINTN          *BufferSize,
+  OUT     VOID           *Buffer
+  );
+
+/**
+  Get volume and free space size information of an UDF volume.
+
+  @param[in]   BlockIo        BlockIo interface.
+  @param[in]   DiskIo         DiskIo interface.
+  @param[in]   Volume         UDF volume information structure.
+  @param[out]  VolumeSize     Volume size.
+  @param[out]  FreeSpaceSize  Free space size.
+
+  @retval EFI_SUCCESS          Volume and free space size calculated.
+  @retval EFI_NO_MEDIA         The device has no media.
+  @retval EFI_DEVICE_ERROR     The device reported an error.
+  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
+  @retval EFI_OUT_OF_RESOURCES The volume and free space size were not
+                               calculated due to lack of resources.
+
+**/
+EFI_STATUS
+GetVolumeSize (
+  IN   EFI_BLOCK_IO_PROTOCOL  *BlockIo,
+  IN   EFI_DISK_IO_PROTOCOL   *DiskIo,
+  IN   UDF_VOLUME_INFO        *Volume,
+  OUT  UINT64                 *VolumeSize,
+  OUT  UINT64                 *FreeSpaceSize
+  );
+
+/**
+  Mangle a filename by cutting off trailing whitespaces, "\\", "." and "..".
+
+  @param[in] FileName Filename.
+
+  @retval @p FileName Filename mangled.
+
+**/
+CHAR16 *
+MangleFileName (
+  IN CHAR16        *FileName
+  );
+
+/**
+  Test to see if this driver supports ControllerHandle. Any ControllerHandle
+  than contains a BlockIo and DiskIo protocol can be supported.
+
+  @param  This                Protocol instance pointer.
+  @param  ControllerHandle    Handle of device to test
+  @param  RemainingDevicePath Optional parameter use to pick a specific child
+                              device to start.
+
+  @retval EFI_SUCCESS         This driver supports this device
+  @retval EFI_ALREADY_STARTED This driver is already running on this device
+  @retval other               This driver does not support this device
+
+**/
+EFI_STATUS
+EFIAPI
+UdfDriverBindingSupported (
+  IN EFI_DRIVER_BINDING_PROTOCOL  *This,
+  IN EFI_HANDLE                   ControllerHandle,
+  IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath
+  );
+
+/**
+  Start this driver on ControllerHandle by opening a Block IO and Disk IO
+  protocol, reading Device Path, and creating a child handle with a
+  Disk IO and device path protocol.
+
+  @param  This                 Protocol instance pointer.
+  @param  ControllerHandle     Handle of device to bind driver to
+  @param  RemainingDevicePath  Optional parameter use to pick a specific child
+                               device to start.
+
+  @retval EFI_SUCCESS          This driver is added to ControllerHandle
+  @retval EFI_ALREADY_STARTED  This driver is already running on ControllerHandle
+  @retval other                This driver does not support this device
+
+**/
+EFI_STATUS
+EFIAPI
+UdfDriverBindingStart (
+  IN EFI_DRIVER_BINDING_PROTOCOL  *This,
+  IN EFI_HANDLE                   ControllerHandle,
+  IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath
+  );
+
+/**
+  Stop this driver on ControllerHandle. Support stopping any child handles
+  created by this driver.
+
+  @param  This              Protocol instance pointer.
+  @param  ControllerHandle  Handle of device to stop driver on
+  @param  NumberOfChildren  Number of Handles in ChildHandleBuffer. If number of
+                            children is zero stop the entire bus driver.
+  @param  ChildHandleBuffer List of Child Handles to Stop.
+
+  @retval EFI_SUCCESS       This driver is removed ControllerHandle
+  @retval other             This driver was not removed from this device
+
+**/
+EFI_STATUS
+EFIAPI
+UdfDriverBindingStop (
+  IN  EFI_DRIVER_BINDING_PROTOCOL   *This,
+  IN  EFI_HANDLE                    ControllerHandle,
+  IN  UINTN                         NumberOfChildren,
+  IN  EFI_HANDLE                    *ChildHandleBuffer
+  );
+
+//
+// EFI Component Name Functions
+//
+/**
+  Retrieves a Unicode string that is the user readable name of the driver.
+
+  This function retrieves the user readable name of a driver in the form of a
+  Unicode string. If the driver specified by This has a user readable name in
+  the language specified by Language, then a pointer to the driver name is
+  returned in DriverName, and EFI_SUCCESS is returned. If the driver specified
+  by This does not support the language specified by Language,
+  then EFI_UNSUPPORTED is returned.
+
+  @param  This[in]              A pointer to the EFI_COMPONENT_NAME2_PROTOCOL or
+                                EFI_COMPONENT_NAME_PROTOCOL instance.
+
+  @param  Language[in]          A pointer to a Null-terminated ASCII string
+                                array indicating the language. This is the
+                                language of the driver name that the caller is
+                                requesting, and it must match one of the
+                                languages specified in SupportedLanguages. The
+                                number of languages supported by a driver is up
+                                to the driver writer. Language is specified
+                                in RFC 4646 or ISO 639-2 language code format.
+
+  @param  DriverName[out]       A pointer to the Unicode string to return.
+                                This Unicode string is the name of the
+                                driver specified by This in the language
+                                specified by Language.
+
+  @retval EFI_SUCCESS           The Unicode string for the Driver specified by
+                                This and the language specified by Language was
+                                returned in DriverName.
+
+  @retval EFI_INVALID_PARAMETER Language is NULL.
+
+  @retval EFI_INVALID_PARAMETER DriverName is NULL.
+
+  @retval EFI_UNSUPPORTED       The driver specified by This does not support
+                                the language specified by Language.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfComponentNameGetDriverName (
+  IN  EFI_COMPONENT_NAME_PROTOCOL  *This,
+  IN  CHAR8                        *Language,
+  OUT CHAR16                       **DriverName
+  );
+
+/**
+  Retrieves a Unicode string that is the user readable name of the controller
+  that is being managed by a driver.
+
+  This function retrieves the user readable name of the controller specified by
+  ControllerHandle and ChildHandle in the form of a Unicode string. If the
+  driver specified by This has a user readable name in the language specified by
+  Language, then a pointer to the controller name is returned in ControllerName,
+  and EFI_SUCCESS is returned.  If the driver specified by This is not currently
+  managing the controller specified by ControllerHandle and ChildHandle,
+  then EFI_UNSUPPORTED is returned.  If the driver specified by This does not
+  support the language specified by Language, then EFI_UNSUPPORTED is returned.
+
+  @param  This[in]              A pointer to the EFI_COMPONENT_NAME2_PROTOCOL or
+                                EFI_COMPONENT_NAME_PROTOCOL instance.
+
+  @param  ControllerHandle[in]  The handle of a controller that the driver
+                                specified by This is managing.  This handle
+                                specifies the controller whose name is to be
+                                returned.
+
+  @param  ChildHandle[in]       The handle of the child controller to retrieve
+                                the name of.  This is an optional parameter that
+                                may be NULL.  It will be NULL for device
+                                drivers.  It will also be NULL for a bus drivers
+                                that wish to retrieve the name of the bus
+                                controller.  It will not be NULL for a bus
+                                driver that wishes to retrieve the name of a
+                                child controller.
+
+  @param  Language[in]          A pointer to a Null-terminated ASCII string
+                                array indicating the language.  This is the
+                                language of the driver name that the caller is
+                                requesting, and it must match one of the
+                                languages specified in SupportedLanguages. The
+                                number of languages supported by a driver is up
+                                to the driver writer. Language is specified in
+                                RFC 4646 or ISO 639-2 language code format.
+
+  @param  ControllerName[out]   A pointer to the Unicode string to return.
+                                This Unicode string is the name of the
+                                controller specified by ControllerHandle and
+                                ChildHandle in the language specified by
+                                Language from the point of view of the driver
+                                specified by This.
+
+  @retval EFI_SUCCESS           The Unicode string for the user readable name in
+                                the language specified by Language for the
+                                driver specified by This was returned in
+                                DriverName.
+
+  @retval EFI_INVALID_PARAMETER ControllerHandle is not a valid EFI_HANDLE.
+
+  @retval EFI_INVALID_PARAMETER ChildHandle is not NULL and it is not a valid
+                                EFI_HANDLE.
+
+  @retval EFI_INVALID_PARAMETER Language is NULL.
+
+  @retval EFI_INVALID_PARAMETER ControllerName is NULL.
+
+  @retval EFI_UNSUPPORTED       The driver specified by This is not currently
+                                managing the controller specified by
+                                ControllerHandle and ChildHandle.
+
+  @retval EFI_UNSUPPORTED       The driver specified by This does not support
+                                the language specified by Language.
+
+**/
+EFI_STATUS
+EFIAPI
+UdfComponentNameGetControllerName (
+  IN   EFI_COMPONENT_NAME_PROTOCOL  *This,
+  IN   EFI_HANDLE                   ControllerHandle,
+  IN   EFI_HANDLE                   ChildHandle OPTIONAL,
+  IN   CHAR8                        *Language,
+  OUT  CHAR16                       **ControllerName
+  );
+
+#endif // _UDF_H_
diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/UdfDxe.inf b/MdeModulePkg/Universal/Disk/UdfDxe/UdfDxe.inf
new file mode 100644
index 0000000000..5be2959bdc
--- /dev/null
+++ b/MdeModulePkg/Universal/Disk/UdfDxe/UdfDxe.inf
@@ -0,0 +1,66 @@
+## @file
+#  UDF/ECMA-167 file system driver.
+#
+#  Copyright (C) 2014-2017 Paulo Alcantara <pcacjr@zytor.com>
+#
+#  This program and the accompanying materials
+#  are licensed and made available under the terms and conditions of the BSD License
+#  which accompanies this distribution.  The full text of the license may be found at
+#  http://opensource.org/licenses/bsd-license.php
+#
+#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = UdfDxe
+  FILE_GUID                      = 905f13b0-8f91-4b0a-bd76-e1e78f9422e4
+  MODULE_TYPE                    = UEFI_DRIVER
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = InitializeUdf
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64 IPF EBC
+#
+#  DRIVER_BINDING                = gUdfDriverBinding
+#  COMPONENT_NAME                = gUdfComponentName
+#  COMPONENT_NAME2               = gUdfComponentName2
+#
+
+[Sources]
+  ComponentName.c
+  FileSystemOperations.c
+  FileName.c
+  File.c
+  Udf.c
+  Udf.h
+
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+
+[LibraryClasses]
+  DevicePathLib
+  UefiBootServicesTableLib
+  MemoryAllocationLib
+  BaseMemoryLib
+  UefiLib
+  BaseLib
+  UefiDriverEntryPoint
+  DebugLib
+
+
+[Guids]
+  gEfiFileInfoGuid                              ## SOMETIMES_CONSUMES ## Protocol
+  gEfiFileSystemInfoGuid                        ## SOMETIMES_CONSUMES ## Protocol
+
+
+[Protocols]
+  gEfiSimpleFileSystemProtocolGuid              ## BY_START
+  gEfiDevicePathProtocolGuid                    ## BY_START
+  gEfiBlockIoProtocolGuid                       ## TO_START
+  gEfiDiskIoProtocolGuid                        ## TO_START
-- 
2.11.0

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