Copy file using FATFS in Same logical drive

MCU - stm32f407vgt6
IDE - True Studio
Additional - CubeMx

Description -
I am trying to copy a file from USB drive to the same USB drive with diffrent name.

Source File - FILE2.txt - This file is present in the drive and Size is 3KB
Destination File - file2copy.txt - This file will be created in the same drive and contents of FILE2.txt will be copied.

Code -

int CopyFile(char *srcFile, char *destFile)
{
    FATFS fs0;
    FIL fsrc, fdest;
    BYTE buffer[4096];
    FRESULT res;
    UINT br, bw;

    f_mount(&fs0, USBHPath, 0);

    res = f_open(&fsrc, (const TCHAR*)srcFile, FA_READ | FA_OPEN_EXISTING);
    if (res)    return 0;
    else
    {
        Green_Blink(100);
        res = f_open(&fdest, (const TCHAR*)destFile, FA_WRITE | FA_CREATE_ALWAYS);
        if (res)   return 0;
        else
        {
            Green_Blink(100);
            for (;;) {
                res = f_read(&fsrc, buffer, sizeof buffer, &br);  /* Read a chunk of source file */
                if (res || br == 0) break; /* error or eof */
                res = f_write(&fdest, buffer, br, &bw);            /* Write it to the destination file */
                if (res || bw < br) break; /* error or disk full */
                f_sync(&fdest);
            }
        }
    }
    f_close(&fsrc);
    f_close(&fdest);

    f_mount(0, USBHPath, 0);

    return 1;
}

ERROR -
I am able to open the source file but cannot create the destination file in the drive.

res = f_open(&fdest, (const TCHAR*)destFile, FA_WRITE | FA_CREATE_ALWAYS);
if (res)   return 0;

res becomes true in the case.

So my question is how do i copy file in same logical drive and what is the problem with opening the destination file in that drive.

Thanks in advance.

Firstly, I don't know about your stack settings but variables FATFS fs0; and BYTE buffer[4096]; may heavy for location on the stack. Be sure that stack size more than 4096 + FF_MAX_SS

Secondly, What kind of error did you get? This enum should be useful:

 typedef enum {
    FR_OK = 0,              /* (0) Succeeded */
    FR_DISK_ERR,            /* (1) A hard error occurred in the low level disk I/O layer */
    FR_INT_ERR,             /* (2) Assertion failed */
    FR_NOT_READY,           /* (3) The physical drive cannot work */
    FR_NO_FILE,             /* (4) Could not find the file */
    FR_NO_PATH,             /* (5) Could not find the path */
    FR_INVALID_NAME,        /* (6) The path name format is invalid */
    FR_DENIED,              /* (7) Access denied due to prohibited access or directory full */
    FR_EXIST,               /* (8) Access denied due to prohibited access */
    FR_INVALID_OBJECT,      /* (9) The file/directory object is invalid */
    FR_WRITE_PROTECTED,     /* (10) The physical drive is write protected */
    FR_INVALID_DRIVE,       /* (11) The logical drive number is invalid */
    FR_NOT_ENABLED,         /* (12) The volume has no work area */
    FR_NO_FILESYSTEM,       /* (13) There is no valid FAT volume */
    FR_MKFS_ABORTED,        /* (14) The f_mkfs() aborted due to any problem */
    FR_TIMEOUT,             /* (15) Could not get a grant to access the volume within defined period */
    FR_LOCKED,              /* (16) The operation is rejected according to the file sharing policy */
    FR_NOT_ENOUGH_CORE,     /* (17) LFN working buffer could not be allocated */
    FR_TOO_MANY_OPEN_FILES, /* (18) Number of open files > FF_FS_LOCK */
    FR_INVALID_PARAMETER    /* (19) Given parameter is invalid */
} FRESULT;

And, try to don't keep open two files simultaneously:

int CopyFile(char *srcFile, char *destFile)
{
    FATFS fs0;
    FIL file;
    BYTE buffer[4096];
    FRESULT res;
    UINT br = 0, bw = 0;

    f_mount(&fs0, USBHPath, 0);

    res = f_open(&file, (const TCHAR*)srcFile, FA_READ | FA_OPEN_EXISTING);
    if (res){
        f_mount(0, USBHPath, 0);
        return 0;
    }

    f_read(&file, buffer, sizeof(buffer), &br);  /* Read a chunk of source file */
    f_close(&file);

    if(br) {
        Green_Blink(100);

        res = f_open(&file, (const TCHAR*)destFile, FA_WRITE | FA_CREATE_ALWAYS);
        if (res) {
            f_mount(0, USBHPath, 0);
            return 0;
        }

        Green_Blink(100);

        f_write(&file, buffer, br, &bw); /* Write it to the destination file */
        f_close(&file);

        if(!bw) {
            f_mount(0, USBHPath, 0);
            return 0;
        }

    }

    f_mount(0, USBHPath, 0);

    return 1;
}