FreeRTOS · Old-Ding · Jul 1, 2026 · Jul 10, 2026 · Jul 10, 2026 · Jul 12, 2026
diff --git a/ff_file.c b/ff_file.c
@@ -1512,13 +1512,16 @@ static FF_Error_t FF_ExtendFile( FF_FILE * pxFile,
 
 static FF_Error_t FF_WriteClusters( FF_FILE * pxFile,
                                     uint32_t ulCount,
-                                    uint8_t * buffer )
+                                    uint8_t * buffer,
+                                    uint32_t * pulClustersWritten )
 {
     uint32_t ulSectors;
     uint32_t ulSequentialClusters = 0;
     uint32_t ulItemLBA;
     FF_Error_t xError = FF_ERR_NONE;
 
+    *pulClustersWritten = 0U;
+
     while( ulCount != 0 )
     {
         if( ulCount > 1U )
@@ -1547,6 +1550,7 @@ static FF_Error_t FF_WriteClusters( FF_FILE * pxFile,
             break;
         }
 
+        *pulClustersWritten += ulSequentialClusters + 1U;
         ulCount -= ulSequentialClusters + 1;
 
         FF_LockFAT( pxFile->pxIOManager );
@@ -2376,6 +2380,7 @@ int32_t FF_Write( FF_FILE * pxFile,
             if( ulBytesLeft >= ulBytesPerCluster )
             {
                 uint32_t ulClusters;
+                uint32_t ulClustersWritten;
 
                 FF_SetCluster( pxFile, &xError );
 
@@ -2386,7 +2391,8 @@ int32_t FF_Write( FF_FILE * pxFile,
 
                 ulClusters = ( ulBytesLeft / ulBytesPerCluster );
 
-                xError = FF_WriteClusters( pxFile, ulClusters, pucBuffer );
+                xError = FF_WriteClusters( pxFile, ulClusters, pucBuffer, &ulClustersWritten );
+                nBytesWritten += ulBytesPerCluster * ulClustersWritten;
 
                 if( FF_isERR( xError ) )
                 {
@@ -2396,7 +2402,6 @@ int32_t FF_Write( FF_FILE * pxFile,
                 nBytesToWrite = ulBytesPerCluster * ulClusters;
                 ulBytesLeft -= nBytesToWrite;
                 pucBuffer += nBytesToWrite;
-                nBytesWritten += nBytesToWrite;
                 pxFile->ulFilePointer += nBytesToWrite;
 
                 if( pxFile->ulFilePointer > pxFile->ulFileSize )
@@ -2465,12 +2470,16 @@ int32_t FF_Write( FF_FILE * pxFile,
                 break;
             }
 
-            FF_WritePartial( pxFile, ulItemLBA, 0, ulBytesLeft, pucBuffer, &xError );
-            nBytesWritten += ulBytesLeft;
+            nBytesWritten += FF_WritePartial( pxFile, ulItemLBA, 0, ulBytesLeft, pucBuffer, &xError );
         }
         while( pdFALSE );
     }
 
+    if( nBytesWritten > 0U )
+    {
+        pxFile->ulValidFlags |= FF_VALID_FLAG_MODIFIED;
+    }
+
     if( FF_isERR( xError ) )
     {
         lResult = xError;
@@ -2550,6 +2559,7 @@ int32_t FF_PutC( FF_FILE * pxFile,
 
             if( FF_isERR( xResult ) == pdFALSE )
             {
+                pxFile->ulValidFlags |= FF_VALID_FLAG_MODIFIED;
                 xResult = ( FF_Error_t ) ucValue;
             }
         } while( pdFALSE );
@@ -3143,16 +3153,37 @@ FF_Error_t FF_Close( FF_FILE * pxFile )
                 xError = FF_GetEntry( pxFile->pxIOManager, pxFile->usDirEntry, pxFile->ulDirCluster, &xOriginalEntry );
 
                 /* Now update the directory entry */
-                if( ( FF_isERR( xError ) == pdFALSE ) &&
-                    ( ( pxFile->ulFileSize != xOriginalEntry.ulFileSize ) || ( pxFile->ulFileSize == 0UL ) ) )
+                if( FF_isERR( xError ) == pdFALSE )
                 {
-                    if( pxFile->ulFileSize == 0UL )
+                    BaseType_t xUpdateDirectoryEntry = pdFALSE;
+
+                    if( ( pxFile->ulFileSize != xOriginalEntry.ulFileSize ) || ( pxFile->ulFileSize == 0UL ) )
                     {
-                        xOriginalEntry.ulObjectCluster = 0;
+                        if( pxFile->ulFileSize == 0UL )
+                        {
+                            xOriginalEntry.ulObjectCluster = 0;
+                        }
+
+                        xOriginalEntry.ulFileSize = pxFile->ulFileSize;
+                        xUpdateDirectoryEntry = pdTRUE;
                     }
 
-                    xOriginalEntry.ulFileSize = pxFile->ulFileSize;
-                    xError = FF_PutEntry( pxFile->pxIOManager, pxFile->usDirEntry, pxFile->ulDirCluster, &xOriginalEntry, NULL );
+                    #if ( ffconfigTIME_SUPPORT != 0 ) && ( ffconfigUPDATE_FILE_MODIFIED_TIME_ON_CLOSE != 0 )
+                    {
+                        if( ( pxFile->ulValidFlags & FF_VALID_FLAG_MODIFIED ) != 0U )
+                        {
+                            /* Reuse this directory-entry write so timestamp
+                             * maintenance does not add another disk update. */
+                            ( void ) FF_GetSystemTime( &xOriginalEntry.xModifiedTime );
+                            xUpdateDirectoryEntry = pdTRUE;
+                        }
+                    }
+                    #endif /* ffconfigTIME_SUPPORT && ffconfigUPDATE_FILE_MODIFIED_TIME_ON_CLOSE */
+
+                    if( xUpdateDirectoryEntry != pdFALSE )
+                    {
+                        xError = FF_PutEntry( pxFile->pxIOManager, pxFile->usDirEntry, pxFile->ulDirCluster, &xOriginalEntry, NULL );
+                    }
                 }
             }
         }
@@ -3230,6 +3261,7 @@ FF_Error_t FF_Close( FF_FILE * pxFile )
 FF_Error_t FF_SetEof( FF_FILE * pxFile )
 {
     FF_Error_t xError;
+    uint32_t ulOriginalFileSize = pxFile->ulFileSize;
 
     /* Check if the file was not deleted and if it was opened with write permissions: */
     if( ( ( pxFile->ulValidFlags & FF_VALID_FLAG_DELETED ) == 0 ) &&
@@ -3245,6 +3277,11 @@ FF_Error_t FF_SetEof( FF_FILE * pxFile )
         {
             xError = FF_ERR_NONE;
         }
+
+        if( ( FF_isERR( xError ) == pdFALSE ) && ( pxFile->ulFileSize != ulOriginalFileSize ) )
+        {
+            pxFile->ulValidFlags |= FF_VALID_FLAG_MODIFIED;
+        }
     }
     else
     {

diff --git a/include/FreeRTOSFATConfigDefaults.h b/include/FreeRTOSFATConfigDefaults.h
@@ -218,6 +218,16 @@
     #define ffconfigTIME_SUPPORT    0
 #endif
 
+#if !defined( ffconfigUPDATE_FILE_MODIFIED_TIME_ON_CLOSE )
+
+/* Set to 1 to update a file's modified timestamp when closing a file that was
+ * changed through FF_Write(), FF_PutC(), or FF_SetEof().
+ *
+ * Set to 0 to preserve the historical behaviour and avoid extra directory
+ * entry writes on close. */
+    #define ffconfigUPDATE_FILE_MODIFIED_TIME_ON_CLOSE    0
+#endif
+
 #if !defined( ffconfigREMOVABLE_MEDIA )
 
 /* Set to 1 if the media is removable (such as a memory card).

diff --git a/include/ff_file.h b/include/ff_file.h
@@ -82,6 +82,7 @@ typedef struct _FF_FILE
 #define FF_VALID_FLAG_INVALID     0x00000001U
 #define FF_VALID_FLAG_DELETED     0x00000002U
 #define FF_VALID_FLAG_EXTENDED    0x00000004U
+#define FF_VALID_FLAG_MODIFIED    0x00000008U
 
 /*---------- PROTOTYPES */
 /* PUBLIC (Interfaces): */

diff --git a/test/unit-test/CMakeLists.txt b/test/unit-test/CMakeLists.txt
@@ -108,13 +108,76 @@ create_test( ${utest_name}
              "${utest_link_list}"
              "${utest_dep_list}"
              "${test_include_directories}" )
+set( coverage_dep_list ${utest_name} )
+
+set( project_name "ff_file" )
+
+# =====================  Mocks  ================================================
+# Keep the ff_file unit focused on metadata updates from FF_Write() and
+# FF_Close().  The module is built with function sections so the linker can
+# discard unrelated file APIs and their dependencies.
+set( mock_list "" )
+list( APPEND mock_list
+      ${MODULE_ROOT_DIR}/include/ff_locking.h
+      ${UNIT_TEST_DIR}/include/ff_dir_mock_subset.h
+      ${MODULE_ROOT_DIR}/include/ff_fat.h
+      ${UNIT_TEST_DIR}/include/ff_ioman_mock_subset.h
+      ${MODULE_ROOT_DIR}/include/ff_time.h )
+
+set( mock_include_list ${FAT_TEST_INCLUDE_DIRS} )
+set( mock_define_list "" )
+
+# ==================  Module under test  =======================================
+set( real_source_files "" )
+list( APPEND real_source_files
+      ${MODULE_ROOT_DIR}/ff_file.c )
+
+set( real_include_directories ${FAT_TEST_INCLUDE_DIRS} )
+
+# =====================  Test code  ============================================
+set( test_include_directories ${FAT_TEST_INCLUDE_DIRS} )
+
+# ==============================================================================
+set( mock_name "${project_name}_mock" )
+set( real_name "${project_name}_real" )
+
+create_mock_list( ${mock_name}
+                  "${mock_list}"
+                  "${MODULE_ROOT_DIR}/tools/cmock/project.yml"
+                  "${mock_include_list}"
+                  "${mock_define_list}" )
+
+create_real_library( ${real_name}
+                     "${real_source_files}"
+                     "${real_include_directories}"
+                     "${mock_name}" )
+target_compile_options( ${real_name} PRIVATE -ffunction-sections -fdata-sections )
+
+set( utest_dep_list "" )
+list( APPEND utest_dep_list ${real_name} )
+
+set( utest_link_list "" )
+list( APPEND utest_link_list
+      lib${real_name}.a
+      -l${mock_name}
+      -Wl,--gc-sections )
+
+set( utest_name "${project_name}_utest" )
+set( utest_source "${UNIT_TEST_DIR}/ff_file_utest.c" )
+
+create_test( ${utest_name}
+             ${utest_source}
+             "${utest_link_list}"
+             "${utest_dep_list}"
+             "${test_include_directories}" )
+list( APPEND coverage_dep_list ${utest_name} )
 
 # ------------------------------------------------------------------------------
 # `coverage` target: run the tests and collect lcov data into coverage.info.
 # ------------------------------------------------------------------------------
 add_custom_target( coverage
     COMMAND ${CMAKE_COMMAND} -DCMAKE_BINARY_DIR=${CMAKE_BINARY_DIR}
             -P ${MODULE_ROOT_DIR}/tools/cmock/coverage.cmake
-    DEPENDS ${utest_name}
+    DEPENDS ${coverage_dep_list}
     WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
     COMMENT "Running unit tests and collecting coverage" )
diff --git a/test/unit-test/config/FreeRTOSFATConfig.h b/test/unit-test/config/FreeRTOSFATConfig.h
@@ -37,7 +37,10 @@
  * helpers (FF_GetFreeSize / FF_GetVolumeSize) it generates the 64-bit variant.
  * Select the matching 64-bit configuration here so the real declarations agree
  * with the generated mocks. */
-#define ffconfig64_NUM_SUPPORT    ( 1 )
+#define ffconfig64_NUM_SUPPORT                        ( 1 )
+
+#define ffconfigTIME_SUPPORT                          ( 1 )
+#define ffconfigUPDATE_FILE_MODIFIED_TIME_ON_CLOSE    ( 1 )
 
 /* All other ffconfig values fall back to FreeRTOSFATConfigDefaults.h. */