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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** FileX Component */
/** */
/** Fault Tolerant */
/** */
/**************************************************************************/
/**************************************************************************/
#define FX_SOURCE_CODE
#include "fx_api.h"
#include "fx_fault_tolerant.h"
#include "fx_utility.h"
#ifdef FX_ENABLE_FAULT_TOLERANT
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _fx_fault_tolerant_transaction_end PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function completes a file system update operation protected */
/* by fault tolerant. This function first computes the checksum */
/* for the log entries, flush the log file to the file system (a */
/* necessary step to record vital information for the file system to */
/* recover, in case the update operation fails midway). After the */
/* log entries are written to the physical medium, the actualy file */
/* system changes (FAT table, directory entries) are applied. */
/* */
/* If the file system changes are successfully applied, the log */
/* entries can be removed. */
/* */
/* INPUT */
/* */
/* media_ptr Media control block pointer */
/* */
/* OUTPUT */
/* */
/* return status */
/* */
/* CALLS */
/* */
/* _fx_utility_16_unsigned_write Write a USHORT from memory */
/* _fx_fault_tolerant_apply_logs Apply logs into file system */
/* _fx_fault_tolerant_calculate_checksum Compute Checksum of data */
/* _fx_fault_tolerant_write_log_file Write log file */
/* _fx_fault_tolerant_reset_log_file Reset the log file */
/* */
/* CALLED BY */
/* */
/* _fx_directory_attributes_set */
/* _fx_directory_create */
/* _fx_directory_delete */
/* _fx_directory_rename */
/* _fx_file_allocate */
/* _fx_file_attributes_set */
/* _fx_file_best_effort_allocate */
/* _fx_file_create */
/* _fx_file_delete */
/* _fx_file_rename */
/* _fx_file_truncate */
/* _fx_file_truncate_release */
/* _fx_file_write */
/* _fx_unicode_directory_create */
/* _fx_unicode_file_create */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 William E. Lamie Initial Version 6.0 */
/* 09-30-2020 William E. Lamie Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
UINT _fx_fault_tolerant_transaction_end(FX_MEDIA *media_ptr)
{
ULONG relative_sector;
UINT status;
USHORT checksum;
UINT offset;
FX_FAULT_TOLERANT_LOG_HEADER *log_header;
FX_FAULT_TOLERANT_LOG_CONTENT *log_content;
/* Is fault tolerant enabled? */
if (media_ptr -> fx_media_fault_tolerant_enabled == FX_FALSE)
{
return(FX_SUCCESS);
}
/* Decrease the transaction. */
media_ptr -> fx_media_fault_tolerant_transaction_count--;
/* Is transaction finished? */
if (media_ptr -> fx_media_fault_tolerant_transaction_count != 0)
{
return(FX_SUCCESS);
}
/* Close this transaction. */
media_ptr -> fx_media_fault_tolerant_state = FX_FAULT_TOLERANT_STATE_IDLE;
/* Set log header and FAT chain pointer. */
log_header = (FX_FAULT_TOLERANT_LOG_HEADER *)media_ptr -> fx_media_fault_tolerant_memory_buffer;
log_content = (FX_FAULT_TOLERANT_LOG_CONTENT *)(media_ptr -> fx_media_fault_tolerant_memory_buffer +
FX_FAULT_TOLERANT_LOG_CONTENT_OFFSET);
/* Reset checksum field and update log entry counter field. */
_fx_utility_16_unsigned_write((UCHAR *)&log_content -> fx_fault_tolerant_log_content_checksum, 0);
_fx_utility_16_unsigned_write((UCHAR *)&log_content -> fx_fault_tolerant_log_content_count,
media_ptr -> fx_media_fault_tolerant_total_logs);
/* Now calculate the checksum of log content. */
checksum = _fx_fault_tolerant_calculate_checksum((media_ptr -> fx_media_fault_tolerant_memory_buffer +
FX_FAULT_TOLERANT_LOG_CONTENT_OFFSET),
(media_ptr -> fx_media_fault_tolerant_file_size -
FX_FAULT_TOLERANT_LOG_CONTENT_OFFSET));
/* Record checksum field of log content. */
_fx_utility_16_unsigned_write((UCHAR *)&log_content -> fx_fault_tolerant_log_content_checksum, checksum);
/* Record log header. */
_fx_utility_16_unsigned_write((UCHAR *)&log_header -> fx_fault_tolerant_log_header_total_size,
media_ptr -> fx_media_fault_tolerant_file_size);
_fx_utility_16_unsigned_write((UCHAR *)&log_header -> fx_fault_tolerant_log_header_checksum, 0);
/* Calculate checksum of the header. */
checksum = _fx_fault_tolerant_calculate_checksum((UCHAR *)log_header, FX_FAULT_TOLERANT_LOG_HEADER_SIZE);
/* Record checksum field of the header. */
_fx_utility_16_unsigned_write((UCHAR *)&log_header -> fx_fault_tolerant_log_header_checksum, checksum);
/* Flush log content and flush first sector at last. The first sector contains size of total log file.
* The log file will contain wrong value of size when it is interrupted after first sector flushed to file system. */
relative_sector = 1;
offset = media_ptr -> fx_media_bytes_per_sector;
while (offset < media_ptr -> fx_media_fault_tolerant_file_size)
{
/* Write back the log. */
status = _fx_fault_tolerant_write_log_file(media_ptr, relative_sector);
/* Check for good completion status. */
if (status != FX_SUCCESS)
{
/* Error. */
return(status);
}
/* Increase relative sector and offset. */
relative_sector++;
offset += media_ptr -> fx_media_bytes_per_sector;
}
/* Flush first sector. */
status = _fx_fault_tolerant_write_log_file(media_ptr, 0);
/* Check for good completion status. */
if (status != FX_SUCCESS)
{
/* Error. */
return(status);
}
/* At this pointer, the vital information has been flushed to the physical medium.
Update the file system (FAT table, directory entry) using information recorded in the
log file. */
status = _fx_fault_tolerant_apply_logs(media_ptr);
/* Check for a bad status. */
if (status != FX_SUCCESS)
{
/* Return the bad status. */
return(status);
}
/* The file system has been updated successfully. Remove and reset the fault tolerant
log file. */
status = _fx_fault_tolerant_reset_log_file(media_ptr);
return(status);
}
#endif /* FX_ENABLE_FAULT_TOLERANT */
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