I have a problem that if I play this program, the connection between client and server has been successful. But after that, when we try the client to upload or download jpg file from server, there is some problem. I guess there is some while statement going forever.

client.c
int upload(int sock, const char* file_name){
    FILE *file_fd;
    char buff[1024];
    int bytesread, bytessent = 0;
  
    send(sock, "UPLOAD", strlen("UPLOAD"), 0);
    send(sock, file_name, strlen(file_name), 0);

    file_fd = fopen(file_name, "rb");
    
    while(bytesread = fread(buff, 1, sizeof(buff), file_fd) > 0)
    {
         bytessent = send(sock, buff, bytesread, 0);
    }
    fclose(file_fd);
    remove(file_name);
    return True;
}


int download(int sock, const char* file_name){
  
    FILE *file_fd;
    char buff[1024];
    int bytesgot = 0;

    send(sock, "DOWNLOAD", strlen("DOWNLOAD"), 8);
    send(sock, file_name, strlen(file_name), 0);

    file_fd = fopen(file_name, "wb");

    while(bytesgot = recv(sock, buff, sizeof(buff), 0) > 0)
    {
        fwrite(buff, 1, bytesgot, file_fd);
    }

    fclose(file_fd);
    return True;
}

server.c
while(True){
    n = recv(clnt_sock, buffer1, sizeof(buffer1), 0);
    buffer1[n] = ''; 
    // upload
    if(strncmp(buffer1, "UPLOAD", 6) == 0)
        {
            n = recv(clnt_sock, filename, sizeof(filename), 0);
            
            file_fd = fopen(filename, "wb");
            filename[n] = '';

            while((bytesread = recv(clnt_sock, buffer2, sizeof(buffer2), 0)) > 0) //problem
            {
                fwrite(buffer2, 1, bytesread, file_fd);
            }
            
            
            fclose(file_fd);
        }

    // download
    else if(strncmp(buffer1, "DOWNLOAD", 8) == 0)
        {
            n = recv(clnt_sock, filename, sizeof(filename), 0);
            
            filename[n] = '';

            file_fd = fopen(filename, "rb");

            while((bytesread = fread(buffer2, 1, sizeof(buffer2), file_fd)) > 0)
            {
                send(clnt_sock, buffer2, bytesread, 0);
            }
            fclose(file_fd);
            remove(filename);
        }

I tried many different codes, but it has not been solved.