There is a problem with vsftpd, whereby uploads of files can be copied by Samba before the upload is complete. Vsftpd does not have a file locking feature, unlike the ftp server on AIX for example, and it does not have a hidden stor feature like the proftd server has whereby uploads are given a random hidden filename until the upload is complete. Both of these features allows Samba to monitor a directory and only copy complete files. Vsftpd does not account for this.
I consider this to be a fatal flaw with vsftpd, does anyone have any ideas? I have contacted the developer but no feedback yet.