FatPkg/EnhancedFatDxe/ReadWrite.c - third_party/edk2 - Git at Google

 /** @file
   Functions that perform file read/write.

 Copyright (c) 2005 - 2017, Intel Corporation. All rights reserved.<BR>
 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 "Fat.h"

 /**

   Get the file's position of the file.


   @param  FHand                 - The handle of file.
   @param  Position              - The file's position of the file.

   @retval EFI_SUCCESS           - Get the info successfully.
   @retval EFI_DEVICE_ERROR      - Can not find the OFile for the file.
   @retval EFI_UNSUPPORTED       - The open file is not a file.

 **/
 EFI_STATUS
 EFIAPI
 FatGetPosition (
   IN  EFI_FILE_PROTOCOL *FHand,
   OUT UINT64            *Position
   )
 {
   FAT_IFILE *IFile;
   FAT_OFILE *OFile;

   IFile = IFILE_FROM_FHAND (FHand);
   OFile = IFile->OFile;

   if (OFile->Error == EFI_NOT_FOUND) {
     return EFI_DEVICE_ERROR;
   }

   if (OFile->ODir != NULL) {
     return EFI_UNSUPPORTED;
   }

   *Position = IFile->Position;
   return EFI_SUCCESS;
 }

 /**

   Set the file's position of the file.

   @param  FHand                 - The handle of file.
   @param  Position              - The file's position of the file.

   @retval EFI_SUCCESS           - Set the info successfully.
   @retval EFI_DEVICE_ERROR      - Can not find the OFile for the file.
   @retval EFI_UNSUPPORTED       - Set a directory with a not-zero position.

 **/
 EFI_STATUS
 EFIAPI
 FatSetPosition (
   IN EFI_FILE_PROTOCOL  *FHand,
   IN UINT64             Position
   )
 {
   FAT_IFILE *IFile;
   FAT_OFILE *OFile;

   IFile = IFILE_FROM_FHAND (FHand);
   OFile = IFile->OFile;

   if (OFile->Error == EFI_NOT_FOUND) {
     return EFI_DEVICE_ERROR;
   }

   FatWaitNonblockingTask (IFile);

   //
   // If this is a directory, we can only set back to position 0
   //
   if (OFile->ODir != NULL) {
     if (Position != 0) {
       //
       // Reset current directory cursor;
       //
       return EFI_UNSUPPORTED;
     }

     FatResetODirCursor (OFile);
   }
   //
   // Set the position
   //
   if (Position == (UINT64)-1) {
     Position = OFile->FileSize;
   }
   //
   // Set the position
   //
   IFile->Position = Position;
   return EFI_SUCCESS;
 }

 /**

   Get the file info from the open file of the IFile into Buffer.

   @param  IFile                 - The instance of the open file.
   @param  BufferSize            - Size of Buffer.
   @param  Buffer                - Buffer containing read data.

   @retval EFI_SUCCESS           - Get the file info successfully.
   @retval other                 - An error occurred when operation the disk.

 **/
 EFI_STATUS
 FatIFileReadDir (
   IN     FAT_IFILE              *IFile,
   IN OUT UINTN                  *BufferSize,
      OUT VOID                   *Buffer
   )
 {
   EFI_STATUS  Status;
   FAT_OFILE   *OFile;
   FAT_ODIR    *ODir;
   FAT_DIRENT  *DirEnt;
   UINT32      CurrentPos;

   OFile       = IFile->OFile;
   ODir        = OFile->ODir;
   CurrentPos  = ((UINT32) IFile->Position) / sizeof (FAT_DIRECTORY_ENTRY);

   //
   // We need to relocate the directory
   //
   if (CurrentPos < ODir->CurrentPos) {
     //
     // The directory cursor has been modified by another IFile, we reset the cursor
     //
     FatResetODirCursor (OFile);
   }
   //
   // We seek the next directory entry's position
   //
   do {
     Status = FatGetNextDirEnt (OFile, &DirEnt);
     if (EFI_ERROR (Status) || DirEnt == NULL) {
       //
       // Something error occurred or reach the end of directory,
       // return 0 buffersize
       //
       *BufferSize = 0;
       goto Done;
     }
   } while (ODir->CurrentPos <= CurrentPos);
   Status = FatGetDirEntInfo (OFile->Volume, DirEnt, BufferSize, Buffer);

 Done:
   //
   // Update IFile's Position
   //
   if (!EFI_ERROR (Status)) {
     //
     // Update IFile->Position, if everything is all right
     //
     CurrentPos      = ODir->CurrentPos;
     IFile->Position = CurrentPos * sizeof (FAT_DIRECTORY_ENTRY);
   }

   return Status;
 }

 /**

   Get the file info from the open file of the IFile into Buffer.

   @param FHand                 - The file handle to access.
   @param  IoMode                - Indicate whether the access mode is reading or writing.
   @param  BufferSize            - Size of Buffer.
   @param  Buffer                - Buffer containing read data.
   @param  Token                 - A pointer to the token associated with the transaction.

   @retval EFI_SUCCESS           - Get the file info successfully.
   @retval EFI_DEVICE_ERROR      - Can not find the OFile for the file.
   @retval EFI_VOLUME_CORRUPTED  - The file type of open file is error.
   @retval EFI_WRITE_PROTECTED   - The disk is write protect.
   @retval EFI_ACCESS_DENIED     - The file is read-only.
   @return other                 - An error occurred when operating on the disk.

 **/
 EFI_STATUS
 FatIFileAccess (
   IN     EFI_FILE_PROTOCOL     *FHand,
   IN     IO_MODE               IoMode,
   IN OUT UINTN                 *BufferSize,
   IN OUT VOID                  *Buffer,
   IN     EFI_FILE_IO_TOKEN     *Token
   )
 {
   EFI_STATUS  Status;
   FAT_IFILE   *IFile;
   FAT_OFILE   *OFile;
   FAT_VOLUME  *Volume;
   UINT64      EndPosition;
   FAT_TASK    *Task;

   IFile  = IFILE_FROM_FHAND (FHand);
   OFile  = IFile->OFile;
   Volume = OFile->Volume;
   Task   = NULL;

   //
   // Write to a directory is unsupported
   //
   if ((OFile->ODir != NULL) && (IoMode == WriteData)) {
     return EFI_UNSUPPORTED;
   }

   if (OFile->Error == EFI_NOT_FOUND) {
     return EFI_DEVICE_ERROR;
   }

   if (IoMode == ReadData) {
     //
     // If position is at EOF, then return device error
     //
     if (IFile->Position > OFile->FileSize) {
       return EFI_DEVICE_ERROR;
     }
   } else {
     //
     // Check if the we can write data
     //
     if (Volume->ReadOnly) {
       return EFI_WRITE_PROTECTED;
     }

     if (IFile->ReadOnly) {
       return EFI_ACCESS_DENIED;
     }
   }

   if (Token == NULL) {
     FatWaitNonblockingTask (IFile);
   } else {
     //
     // Caller shouldn't call the non-blocking interfaces if the low layer doesn't support DiskIo2.
     // But if it calls, the below check can avoid crash.
     //
     if (FHand->Revision < EFI_FILE_PROTOCOL_REVISION2) {
       return EFI_UNSUPPORTED;
     }
     Task = FatCreateTask (IFile, Token);
     if (Task == NULL) {
       return EFI_OUT_OF_RESOURCES;
     }
   }

   FatAcquireLock ();

   Status = OFile->Error;
   if (!EFI_ERROR (Status)) {
     if (OFile->ODir != NULL) {
       //
       // Read a directory is supported
       //
       ASSERT (IoMode == ReadData);
       Status = FatIFileReadDir (IFile, BufferSize, Buffer);
       OFile = NULL;
     } else {
       //
       // Access a file
       //
       EndPosition = IFile->Position + *BufferSize;
       if (EndPosition > OFile->FileSize) {
         //
         // The position goes beyond the end of file
         //
         if (IoMode == ReadData) {
           //
           // Adjust the actual size read
           //
           *BufferSize -= (UINTN) EndPosition - OFile->FileSize;
         } else {
           //
           // We expand the file size of OFile
           //
           Status = FatGrowEof (OFile, EndPosition);
           if (EFI_ERROR (Status)) {
             //
             // Must update the file's info into the file's Directory Entry
             // and then flush the dirty cache info into disk.
             //
             *BufferSize = 0;
             FatOFileFlush (OFile);
             OFile = NULL;
             goto Done;
           }

           FatUpdateDirEntClusterSizeInfo (OFile);
         }
       }

       Status = FatAccessOFile (OFile, IoMode, (UINTN) IFile->Position, BufferSize, Buffer, Task);
       IFile->Position += *BufferSize;
     }
   }

   if (Token != NULL) {
     if (!EFI_ERROR (Status)) {
       Status = FatQueueTask (IFile, Task);
     } else {
       FatDestroyTask (Task);
     }
   }

 Done:
   //
   // On EFI_SUCCESS case, not calling FatCleanupVolume():
   // 1) The Cache flush operation is avoided to enhance
   // performance. Caller is responsible to call Flush() when necessary.
   // 2) The volume dirty bit is probably set already, and is expected to be
   // cleaned in subsequent Flush() or other operations.
   // 3) Write operation doesn't affect OFile/IFile structure, so
   // Reference checking is not necessary.
   //
   if (EFI_ERROR (Status)) {
     Status = FatCleanupVolume (Volume, OFile, Status, NULL);
   }

   FatReleaseLock ();
   return Status;
 }

 /**

   Get the file info.

   @param  FHand                 - The handle of the file.
   @param  BufferSize            - Size of Buffer.
   @param  Buffer                - Buffer containing read data.


   @retval EFI_SUCCESS           - Get the file info successfully.
   @retval EFI_DEVICE_ERROR      - Can not find the OFile for the file.
   @retval EFI_VOLUME_CORRUPTED  - The file type of open file is error.
   @return other                 - An error occurred when operation the disk.

 **/
 EFI_STATUS
 EFIAPI
 FatRead (
   IN     EFI_FILE_PROTOCOL  *FHand,
   IN OUT UINTN              *BufferSize,
      OUT VOID               *Buffer
   )
 {
   return FatIFileAccess (FHand, ReadData, BufferSize, Buffer, NULL);
 }

 /**

   Get the file info.

   @param  FHand                 - The handle of the file.
   @param  Token                 - A pointer to the token associated with the transaction.

   @retval EFI_SUCCESS           - Get the file info successfully.
   @retval EFI_DEVICE_ERROR      - Can not find the OFile for the file.
   @retval EFI_VOLUME_CORRUPTED  - The file type of open file is error.
   @return other                 - An error occurred when operation the disk.

 **/
 EFI_STATUS
 EFIAPI
 FatReadEx (
   IN     EFI_FILE_PROTOCOL  *FHand,
   IN OUT EFI_FILE_IO_TOKEN  *Token
   )
 {
   return FatIFileAccess (FHand, ReadData, &Token->BufferSize, Token->Buffer, Token);
 }

 /**

   Write the content of buffer into files.

   @param  FHand                 - The handle of the file.
   @param  BufferSize            - Size of Buffer.
   @param  Buffer                - Buffer containing write data.

   @retval EFI_SUCCESS           - Set the file info successfully.
   @retval EFI_WRITE_PROTECTED   - The disk is write protect.
   @retval EFI_ACCESS_DENIED     - The file is read-only.
   @retval EFI_DEVICE_ERROR      - The OFile is not valid.
   @retval EFI_UNSUPPORTED       - The open file is not a file.
                         - The writing file size is larger than 4GB.
   @return other                 - An error occurred when operation the disk.

 **/
 EFI_STATUS
 EFIAPI
 FatWrite (
   IN     EFI_FILE_PROTOCOL  *FHand,
   IN OUT UINTN              *BufferSize,
   IN     VOID               *Buffer
   )
 {
   return FatIFileAccess (FHand, WriteData, BufferSize, Buffer, NULL);
 }

 /**

   Get the file info.

   @param  FHand                 - The handle of the file.
   @param  Token                 - A pointer to the token associated with the transaction.

   @retval EFI_SUCCESS           - Get the file info successfully.
   @retval EFI_DEVICE_ERROR      - Can not find the OFile for the file.
   @retval EFI_VOLUME_CORRUPTED  - The file type of open file is error.
   @return other                 - An error occurred when operation the disk.

 **/
 EFI_STATUS
 EFIAPI
 FatWriteEx (
   IN     EFI_FILE_PROTOCOL  *FHand,
   IN OUT EFI_FILE_IO_TOKEN  *Token
   )
 {
   return FatIFileAccess (FHand, WriteData, &Token->BufferSize, Token->Buffer, Token);
 }

 /**

   This function reads data from a file or writes data to a file.
   It uses OFile->PosRem to determine how much data can be accessed in one time.

   @param  OFile                 - The open file.
   @param  IoMode                - Indicate whether the access mode is reading or writing.
   @param  Position              - The position where data will be accessed.
   @param  DataBufferSize        - Size of Buffer.
   @param  UserBuffer            - Buffer containing data.
   @param  Task                    point to task instance.

   @retval EFI_SUCCESS           - Access the data successfully.
   @return other                 - An error occurred when operating on the disk.

 **/
 EFI_STATUS
 FatAccessOFile (
   IN     FAT_OFILE      *OFile,
   IN     IO_MODE        IoMode,
   IN     UINTN          Position,
   IN OUT UINTN          *DataBufferSize,
   IN OUT UINT8          *UserBuffer,
   IN FAT_TASK           *Task
   )
 {
   FAT_VOLUME  *Volume;
   UINTN       Len;
   EFI_STATUS  Status;
   UINTN       BufferSize;

   BufferSize  = *DataBufferSize;
   Volume      = OFile->Volume;
   ASSERT_VOLUME_LOCKED (Volume);

   Status = EFI_SUCCESS;
   while (BufferSize > 0) {
     //
     // Seek the OFile to the file position
     //
     Status = FatOFilePosition (OFile, Position, BufferSize);
     if (EFI_ERROR (Status)) {
       break;
     }
     //
     // Clip length to block run
     //
     Len = BufferSize > OFile->PosRem ? OFile->PosRem : BufferSize;

     //
     // Write the data
     //
     Status = FatDiskIo (Volume, IoMode, OFile->PosDisk, Len, UserBuffer, Task);
     if (EFI_ERROR (Status)) {
       break;
     }
     //
     // Data was successfully accessed
     //
     Position   += Len;
     UserBuffer += Len;
     BufferSize -= Len;
     if (IoMode == WriteData) {
       OFile->Dirty    = TRUE;
       OFile->Archive  = TRUE;
     }
     //
     // Make sure no outbound occurred
     //
     ASSERT (Position <= OFile->FileSize);
   }
   //
   // Update the number of bytes accessed
   //
   *DataBufferSize -= BufferSize;
   return Status;
 }

 /**

   Expand OFile by appending zero bytes at the end of OFile.

   @param  OFile                 - The open file.
   @param  ExpandedSize          - The number of zero bytes appended at the end of the file.

   @retval EFI_SUCCESS           - The file is expanded successfully.
   @return other                 - An error occurred when expanding file.

 **/
 EFI_STATUS
 FatExpandOFile (
   IN FAT_OFILE          *OFile,
   IN UINT64             ExpandedSize
   )
 {
   EFI_STATUS  Status;
   UINTN       WritePos;

   WritePos  = OFile->FileSize;
   Status    = FatGrowEof (OFile, ExpandedSize);
   if (!EFI_ERROR (Status)) {
     Status = FatWriteZeroPool (OFile, WritePos);
   }

   return Status;
 }

 /**

   Write zero pool from the WritePos to the end of OFile.

   @param  OFile                 - The open file to write zero pool.
   @param  WritePos              - The number of zero bytes written.

   @retval EFI_SUCCESS           - Write the zero pool successfully.
   @retval EFI_OUT_OF_RESOURCES  - Not enough memory to perform the operation.
   @return other                 - An error occurred when writing disk.

 **/
 EFI_STATUS
 FatWriteZeroPool (
   IN FAT_OFILE  *OFile,
   IN UINTN      WritePos
   )
 {
   EFI_STATUS  Status;
   VOID        *ZeroBuffer;
   UINTN       AppendedSize;
   UINTN       BufferSize;
   UINTN       WriteSize;

   AppendedSize  = OFile->FileSize - WritePos;
   BufferSize    = AppendedSize;
   if (AppendedSize > FAT_MAX_ALLOCATE_SIZE) {
     //
     // If the appended size is larger, maybe we can not allocate the whole
     // memory once. So if the growed size is larger than 10M, we just
     // allocate 10M memory (one healthy system should have 10M available
     // memory), and then write the zerobuffer to the file several times.
     //
     BufferSize = FAT_MAX_ALLOCATE_SIZE;
   }

   ZeroBuffer = AllocateZeroPool (BufferSize);
   if (ZeroBuffer == NULL) {
     return EFI_OUT_OF_RESOURCES;
   }

   do {
     WriteSize     = AppendedSize > BufferSize ? BufferSize : (UINTN) AppendedSize;
     AppendedSize -= WriteSize;
     Status = FatAccessOFile (OFile, WriteData, WritePos, &WriteSize, ZeroBuffer, NULL);
     if (EFI_ERROR (Status)) {
       break;
     }

     WritePos += WriteSize;
   } while (AppendedSize > 0);

   FreePool (ZeroBuffer);
   return Status;
 }

 /**

   Truncate the OFile to smaller file size.

   @param  OFile                 - The open file.
   @param  TruncatedSize         - The new file size.

   @retval EFI_SUCCESS           - The file is truncated successfully.
   @return other                 - An error occurred when truncating file.

 **/
 EFI_STATUS
 FatTruncateOFile (
   IN FAT_OFILE          *OFile,
   IN UINTN              TruncatedSize
   )
 {
   OFile->FileSize = TruncatedSize;
   return FatShrinkEof (OFile);
 }
	/** @file
	Functions that perform file read/write.

	Copyright (c) 2005 - 2017, Intel Corporation. All rights reserved.<BR>
	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 "Fat.h"

	/**

	Get the file's position of the file.


	@param FHand - The handle of file.
	@param Position - The file's position of the file.

	@retval EFI_SUCCESS - Get the info successfully.
	@retval EFI_DEVICE_ERROR - Can not find the OFile for the file.
	@retval EFI_UNSUPPORTED - The open file is not a file.

	**/
	EFI_STATUS
	EFIAPI
	FatGetPosition (
	IN EFI_FILE_PROTOCOL *FHand,
	OUT UINT64 *Position
	)
	{
	FAT_IFILE *IFile;
	FAT_OFILE *OFile;

	IFile = IFILE_FROM_FHAND (FHand);
	OFile = IFile->OFile;

	if (OFile->Error == EFI_NOT_FOUND) {
	return EFI_DEVICE_ERROR;
	}

	if (OFile->ODir != NULL) {
	return EFI_UNSUPPORTED;
	}

	*Position = IFile->Position;
	return EFI_SUCCESS;
	}

	/**

	Set the file's position of the file.

	@param FHand - The handle of file.
	@param Position - The file's position of the file.

	@retval EFI_SUCCESS - Set the info successfully.
	@retval EFI_DEVICE_ERROR - Can not find the OFile for the file.
	@retval EFI_UNSUPPORTED - Set a directory with a not-zero position.

	**/
	EFI_STATUS
	EFIAPI
	FatSetPosition (
	IN EFI_FILE_PROTOCOL *FHand,
	IN UINT64 Position
	)
	{
	FAT_IFILE *IFile;
	FAT_OFILE *OFile;

	IFile = IFILE_FROM_FHAND (FHand);
	OFile = IFile->OFile;

	if (OFile->Error == EFI_NOT_FOUND) {
	return EFI_DEVICE_ERROR;
	}

	FatWaitNonblockingTask (IFile);

	//
	// If this is a directory, we can only set back to position 0
	//
	if (OFile->ODir != NULL) {
	if (Position != 0) {
	//
	// Reset current directory cursor;
	//
	return EFI_UNSUPPORTED;
	}

	FatResetODirCursor (OFile);
	}
	//
	// Set the position
	//
	if (Position == (UINT64)-1) {
	Position = OFile->FileSize;
	}
	//
	// Set the position
	//
	IFile->Position = Position;
	return EFI_SUCCESS;
	}

	/**

	Get the file info from the open file of the IFile into Buffer.

	@param IFile - The instance of the open file.
	@param BufferSize - Size of Buffer.
	@param Buffer - Buffer containing read data.

	@retval EFI_SUCCESS - Get the file info successfully.
	@retval other - An error occurred when operation the disk.

	**/
	EFI_STATUS
	FatIFileReadDir (
	IN FAT_IFILE *IFile,
	IN OUT UINTN *BufferSize,
	OUT VOID *Buffer
	)
	{
	EFI_STATUS Status;
	FAT_OFILE *OFile;
	FAT_ODIR *ODir;
	FAT_DIRENT *DirEnt;
	UINT32 CurrentPos;

	OFile = IFile->OFile;
	ODir = OFile->ODir;
	CurrentPos = ((UINT32) IFile->Position) / sizeof (FAT_DIRECTORY_ENTRY);

	//
	// We need to relocate the directory
	//
	if (CurrentPos < ODir->CurrentPos) {
	//
	// The directory cursor has been modified by another IFile, we reset the cursor
	//
	FatResetODirCursor (OFile);
	}
	//
	// We seek the next directory entry's position
	//
	do {
	Status = FatGetNextDirEnt (OFile, &DirEnt);
	if (EFI_ERROR (Status) \|\| DirEnt == NULL) {
	//
	// Something error occurred or reach the end of directory,
	// return 0 buffersize
	//
	*BufferSize = 0;
	goto Done;
	}
	} while (ODir->CurrentPos <= CurrentPos);
	Status = FatGetDirEntInfo (OFile->Volume, DirEnt, BufferSize, Buffer);

	Done:
	//
	// Update IFile's Position
	//
	if (!EFI_ERROR (Status)) {
	//
	// Update IFile->Position, if everything is all right
	//
	CurrentPos = ODir->CurrentPos;
	IFile->Position = CurrentPos * sizeof (FAT_DIRECTORY_ENTRY);
	}

	return Status;
	}

	/**

	Get the file info from the open file of the IFile into Buffer.

	@param FHand - The file handle to access.
	@param IoMode - Indicate whether the access mode is reading or writing.
	@param BufferSize - Size of Buffer.
	@param Buffer - Buffer containing read data.
	@param Token - A pointer to the token associated with the transaction.

	@retval EFI_SUCCESS - Get the file info successfully.
	@retval EFI_DEVICE_ERROR - Can not find the OFile for the file.
	@retval EFI_VOLUME_CORRUPTED - The file type of open file is error.
	@retval EFI_WRITE_PROTECTED - The disk is write protect.
	@retval EFI_ACCESS_DENIED - The file is read-only.
	@return other - An error occurred when operating on the disk.

	**/
	EFI_STATUS
	FatIFileAccess (
	IN EFI_FILE_PROTOCOL *FHand,
	IN IO_MODE IoMode,
	IN OUT UINTN *BufferSize,
	IN OUT VOID *Buffer,
	IN EFI_FILE_IO_TOKEN *Token
	)
	{
	EFI_STATUS Status;
	FAT_IFILE *IFile;
	FAT_OFILE *OFile;
	FAT_VOLUME *Volume;
	UINT64 EndPosition;
	FAT_TASK *Task;

	IFile = IFILE_FROM_FHAND (FHand);
	OFile = IFile->OFile;
	Volume = OFile->Volume;
	Task = NULL;

	//
	// Write to a directory is unsupported
	//
	if ((OFile->ODir != NULL) && (IoMode == WriteData)) {
	return EFI_UNSUPPORTED;
	}

	if (OFile->Error == EFI_NOT_FOUND) {
	return EFI_DEVICE_ERROR;
	}

	if (IoMode == ReadData) {
	//
	// If position is at EOF, then return device error
	//
	if (IFile->Position > OFile->FileSize) {
	return EFI_DEVICE_ERROR;
	}
	} else {
	//
	// Check if the we can write data
	//
	if (Volume->ReadOnly) {
	return EFI_WRITE_PROTECTED;
	}

	if (IFile->ReadOnly) {
	return EFI_ACCESS_DENIED;
	}
	}

	if (Token == NULL) {
	FatWaitNonblockingTask (IFile);
	} else {
	//
	// Caller shouldn't call the non-blocking interfaces if the low layer doesn't support DiskIo2.
	// But if it calls, the below check can avoid crash.
	//
	if (FHand->Revision < EFI_FILE_PROTOCOL_REVISION2) {
	return EFI_UNSUPPORTED;
	}
	Task = FatCreateTask (IFile, Token);
	if (Task == NULL) {
	return EFI_OUT_OF_RESOURCES;
	}
	}

	FatAcquireLock ();

	Status = OFile->Error;
	if (!EFI_ERROR (Status)) {
	if (OFile->ODir != NULL) {
	//
	// Read a directory is supported
	//
	ASSERT (IoMode == ReadData);
	Status = FatIFileReadDir (IFile, BufferSize, Buffer);
	OFile = NULL;
	} else {
	//
	// Access a file
	//
	EndPosition = IFile->Position + *BufferSize;
	if (EndPosition > OFile->FileSize) {
	//
	// The position goes beyond the end of file
	//
	if (IoMode == ReadData) {
	//
	// Adjust the actual size read
	//
	*BufferSize -= (UINTN) EndPosition - OFile->FileSize;
	} else {
	//
	// We expand the file size of OFile
	//
	Status = FatGrowEof (OFile, EndPosition);
	if (EFI_ERROR (Status)) {
	//
	// Must update the file's info into the file's Directory Entry
	// and then flush the dirty cache info into disk.
	//
	*BufferSize = 0;
	FatOFileFlush (OFile);
	OFile = NULL;
	goto Done;
	}

	FatUpdateDirEntClusterSizeInfo (OFile);
	}
	}

	Status = FatAccessOFile (OFile, IoMode, (UINTN) IFile->Position, BufferSize, Buffer, Task);
	IFile->Position += *BufferSize;
	}
	}

	if (Token != NULL) {
	if (!EFI_ERROR (Status)) {
	Status = FatQueueTask (IFile, Task);
	} else {
	FatDestroyTask (Task);
	}
	}

	Done:
	//
	// On EFI_SUCCESS case, not calling FatCleanupVolume():
	// 1) The Cache flush operation is avoided to enhance
	// performance. Caller is responsible to call Flush() when necessary.
	// 2) The volume dirty bit is probably set already, and is expected to be
	// cleaned in subsequent Flush() or other operations.
	// 3) Write operation doesn't affect OFile/IFile structure, so
	// Reference checking is not necessary.
	//
	if (EFI_ERROR (Status)) {
	Status = FatCleanupVolume (Volume, OFile, Status, NULL);
	}

	FatReleaseLock ();
	return Status;
	}

	/**

	Get the file info.

	@param FHand - The handle of the file.
	@param BufferSize - Size of Buffer.
	@param Buffer - Buffer containing read data.


	@retval EFI_SUCCESS - Get the file info successfully.
	@retval EFI_DEVICE_ERROR - Can not find the OFile for the file.
	@retval EFI_VOLUME_CORRUPTED - The file type of open file is error.
	@return other - An error occurred when operation the disk.

	**/
	EFI_STATUS
	EFIAPI
	FatRead (
	IN EFI_FILE_PROTOCOL *FHand,
	IN OUT UINTN *BufferSize,
	OUT VOID *Buffer
	)
	{
	return FatIFileAccess (FHand, ReadData, BufferSize, Buffer, NULL);
	}

	/**

	Get the file info.

	@param FHand - The handle of the file.
	@param Token - A pointer to the token associated with the transaction.

	@retval EFI_SUCCESS - Get the file info successfully.
	@retval EFI_DEVICE_ERROR - Can not find the OFile for the file.
	@retval EFI_VOLUME_CORRUPTED - The file type of open file is error.
	@return other - An error occurred when operation the disk.

	**/
	EFI_STATUS
	EFIAPI
	FatReadEx (
	IN EFI_FILE_PROTOCOL *FHand,
	IN OUT EFI_FILE_IO_TOKEN *Token
	)
	{
	return FatIFileAccess (FHand, ReadData, &Token->BufferSize, Token->Buffer, Token);
	}

	/**

	Write the content of buffer into files.

	@param FHand - The handle of the file.
	@param BufferSize - Size of Buffer.
	@param Buffer - Buffer containing write data.

	@retval EFI_SUCCESS - Set the file info successfully.
	@retval EFI_WRITE_PROTECTED - The disk is write protect.
	@retval EFI_ACCESS_DENIED - The file is read-only.
	@retval EFI_DEVICE_ERROR - The OFile is not valid.
	@retval EFI_UNSUPPORTED - The open file is not a file.
	- The writing file size is larger than 4GB.
	@return other - An error occurred when operation the disk.

	**/
	EFI_STATUS
	EFIAPI
	FatWrite (
	IN EFI_FILE_PROTOCOL *FHand,
	IN OUT UINTN *BufferSize,
	IN VOID *Buffer
	)
	{
	return FatIFileAccess (FHand, WriteData, BufferSize, Buffer, NULL);
	}

	/**

	Get the file info.

	@param FHand - The handle of the file.
	@param Token - A pointer to the token associated with the transaction.

	@retval EFI_SUCCESS - Get the file info successfully.
	@retval EFI_DEVICE_ERROR - Can not find the OFile for the file.
	@retval EFI_VOLUME_CORRUPTED - The file type of open file is error.
	@return other - An error occurred when operation the disk.

	**/
	EFI_STATUS
	EFIAPI
	FatWriteEx (
	IN EFI_FILE_PROTOCOL *FHand,
	IN OUT EFI_FILE_IO_TOKEN *Token
	)
	{
	return FatIFileAccess (FHand, WriteData, &Token->BufferSize, Token->Buffer, Token);
	}

	/**

	This function reads data from a file or writes data to a file.
	It uses OFile->PosRem to determine how much data can be accessed in one time.

	@param OFile - The open file.
	@param IoMode - Indicate whether the access mode is reading or writing.
	@param Position - The position where data will be accessed.
	@param DataBufferSize - Size of Buffer.
	@param UserBuffer - Buffer containing data.
	@param Task point to task instance.

	@retval EFI_SUCCESS - Access the data successfully.
	@return other - An error occurred when operating on the disk.

	**/
	EFI_STATUS
	FatAccessOFile (
	IN FAT_OFILE *OFile,
	IN IO_MODE IoMode,
	IN UINTN Position,
	IN OUT UINTN *DataBufferSize,
	IN OUT UINT8 *UserBuffer,
	IN FAT_TASK *Task
	)
	{
	FAT_VOLUME *Volume;
	UINTN Len;
	EFI_STATUS Status;
	UINTN BufferSize;

	BufferSize = *DataBufferSize;
	Volume = OFile->Volume;
	ASSERT_VOLUME_LOCKED (Volume);

	Status = EFI_SUCCESS;
	while (BufferSize > 0) {
	//
	// Seek the OFile to the file position
	//
	Status = FatOFilePosition (OFile, Position, BufferSize);
	if (EFI_ERROR (Status)) {
	break;
	}
	//
	// Clip length to block run
	//
	Len = BufferSize > OFile->PosRem ? OFile->PosRem : BufferSize;

	//
	// Write the data
	//
	Status = FatDiskIo (Volume, IoMode, OFile->PosDisk, Len, UserBuffer, Task);
	if (EFI_ERROR (Status)) {
	break;
	}
	//
	// Data was successfully accessed
	//
	Position += Len;
	UserBuffer += Len;
	BufferSize -= Len;
	if (IoMode == WriteData) {
	OFile->Dirty = TRUE;
	OFile->Archive = TRUE;
	}
	//
	// Make sure no outbound occurred
	//
	ASSERT (Position <= OFile->FileSize);
	}
	//
	// Update the number of bytes accessed
	//
	*DataBufferSize -= BufferSize;
	return Status;
	}

	/**

	Expand OFile by appending zero bytes at the end of OFile.

	@param OFile - The open file.
	@param ExpandedSize - The number of zero bytes appended at the end of the file.

	@retval EFI_SUCCESS - The file is expanded successfully.
	@return other - An error occurred when expanding file.

	**/
	EFI_STATUS
	FatExpandOFile (
	IN FAT_OFILE *OFile,
	IN UINT64 ExpandedSize
	)
	{
	EFI_STATUS Status;
	UINTN WritePos;

	WritePos = OFile->FileSize;
	Status = FatGrowEof (OFile, ExpandedSize);
	if (!EFI_ERROR (Status)) {
	Status = FatWriteZeroPool (OFile, WritePos);
	}

	return Status;
	}

	/**

	Write zero pool from the WritePos to the end of OFile.

	@param OFile - The open file to write zero pool.
	@param WritePos - The number of zero bytes written.

	@retval EFI_SUCCESS - Write the zero pool successfully.
	@retval EFI_OUT_OF_RESOURCES - Not enough memory to perform the operation.
	@return other - An error occurred when writing disk.

	**/
	EFI_STATUS
	FatWriteZeroPool (
	IN FAT_OFILE *OFile,
	IN UINTN WritePos
	)
	{
	EFI_STATUS Status;
	VOID *ZeroBuffer;
	UINTN AppendedSize;
	UINTN BufferSize;
	UINTN WriteSize;

	AppendedSize = OFile->FileSize - WritePos;
	BufferSize = AppendedSize;
	if (AppendedSize > FAT_MAX_ALLOCATE_SIZE) {
	//
	// If the appended size is larger, maybe we can not allocate the whole
	// memory once. So if the growed size is larger than 10M, we just
	// allocate 10M memory (one healthy system should have 10M available
	// memory), and then write the zerobuffer to the file several times.
	//
	BufferSize = FAT_MAX_ALLOCATE_SIZE;
	}

	ZeroBuffer = AllocateZeroPool (BufferSize);
	if (ZeroBuffer == NULL) {
	return EFI_OUT_OF_RESOURCES;
	}

	do {
	WriteSize = AppendedSize > BufferSize ? BufferSize : (UINTN) AppendedSize;
	AppendedSize -= WriteSize;
	Status = FatAccessOFile (OFile, WriteData, WritePos, &WriteSize, ZeroBuffer, NULL);
	if (EFI_ERROR (Status)) {
	break;
	}

	WritePos += WriteSize;
	} while (AppendedSize > 0);

	FreePool (ZeroBuffer);
	return Status;
	}

	/**

	Truncate the OFile to smaller file size.

	@param OFile - The open file.
	@param TruncatedSize - The new file size.

	@retval EFI_SUCCESS - The file is truncated successfully.
	@return other - An error occurred when truncating file.

	**/
	EFI_STATUS
	FatTruncateOFile (
	IN FAT_OFILE *OFile,
	IN UINTN TruncatedSize
	)
	{
	OFile->FileSize = TruncatedSize;
	return FatShrinkEof (OFile);
	}