sector allignments in FATfs on external flash with STM32F767

[AShel.1]

I'm using FATfs file system on external flash (16MB) using STM32F767, I'm able to create/ read/ write/ close files.

I've created 4 files: sequence of handing files and sector no assigned to them are as,

Created/ Write File1 - sector 8

Created/ Write File2 - sector 9

Created/ Write File3 - sector 10

unlink File2

Created/ Write File4 - sector 11

before creating File 4 I've deleted File 2 using f_unlink("0:/FILE2.TXT"); function, now I expect if I create File4 then sector no 9 should be assigned to this file as it is free sector after File2 is deleted. Is there any way to reused the free sector after deleting files.

if(f_open(&MyFile, "0:/FILE1.TXT", FA_READ | FA_CREATE_ALWAYS | FA_WRITE) != FR_OK)//FA_CREATE_ALWAYS | FA_WRITE
	    {
	      /* 'STM32.TXT' file Open for write Error */
	      Error_Handler();
	    }
	    else
	    {
	      /* Write data to the text file */
	      res = f_write(&MyFile, wtext, sizeof(wtext), (void *)&byteswritten);
 
	      if((byteswritten == 0) || (res != FR_OK))
	      {
	        /* 'STM32.TXT' file Write or EOF Error */
	        Error_Handler();
	      }
	      else
	      {
	             		if(f_open(&MyFile2, "0:/FILE2.TXT", FA_READ | FA_CREATE_ALWAYS | FA_WRITE) != FR_OK)//FA_CREATE_ALWAYS | FA_WRITE
	        	    {
	        	      /* 'STM32.TXT' file Open for write Error */
	        	      Error_Handler();
	        	    }
	       
	        else
	        {
	        	res = f_write(&MyFile2, wtext2, sizeof(wtext2), (void *)&byteswritten);
 
	        		      if((byteswritten == 0) || (res != FR_OK))
	        		      {
	        		        /* 'STM32.TXT' file Write or EOF Error */
	        		        Error_Handler();
	        		      }
	        		   
	          /* Read data from the text file */
	        		      if(f_open(&MyFile3, "0:/FILE3.TXT", FA_READ | FA_CREATE_ALWAYS | FA_WRITE) != FR_OK)//FA_CREATE_ALWAYS | FA_WRITE
	        		     	    {
	        		     	      /* 'STM32.TXT' file Open for write Error */
	        		     	      Error_Handler();
	        		     	    }
	        		     	    else
	        		     	    {
	        		     	      /* Write data to the text file */
	        		     	      res = f_write(&MyFile3, wtext, sizeof(wtext), (void *)&byteswritten);
 
	        		     	      if((byteswritten == 0) || (res != FR_OK))
	        		     	      {
	        		     	        /* 'STM32.TXT' file Write or EOF Error */
	        		     	        Error_Handler();
	        		     	      }
	        		     	      else
	        		     	      {
 
	        		     	      }
	        		     	    }
	        		      f_unlink("0:/FILE2.TXT");	        		      
	        		    
	        		      if(f_open(&MyFile4, "0:/FILE4.TXT", FA_READ | FA_CREATE_ALWAYS | FA_WRITE) != FR_OK)//FA_CREATE_ALWAYS | FA_WRITE
	        		      	        		     	    {
	        		      	        		     	      /* 'STM32.TXT' file Open for write Error */
	        		      	        		     	      Error_Handler();
	        		      	        		     	    }
	        		      	        		     	    else
	        		      	        		     	    {
	        		      	        		     	      /* Write data to the text file */
	        		      	        		     	      res = f_write(&MyFile4, wtext, sizeof(wtext), (void *)&byteswritten);
 
	        		      	        		     	      if((byteswritten == 0) || (res != FR_OK))
	        		      	        		     	      {
	        		      	        		     	        /* 'STM32.TXT' file Write or EOF Error */
	        		      	        		     	        Error_Handler();
	        		      	        		     	      }
	        		      	        		     	      else
	        		      	        		     	      {
 
	        		      	        		     	      }
	        		      	        		     	    }