[Samba] [Bug] Cannot create file but read/write is ok

[lampahome]

>
> It is a possibility that your users primary group  doesn't exist on the
> computer where you are mounting from.
>
> It also might help if you say what your clients are, the users primary
> group only really makes sense from a Windows machine, where it should be
> 'Domain Users' (if a domain joined computer), or 'Users' if not. From a
> Unix client, the users primary group will also be the users private
> group, which is usually the same as the users name.
>
> Rowland
>
I check it by run groups ppp
And it shows:
ppp : ppp adm cdrom sudo dip plugdev lpadmin sambashare
So it should contain the samba group, but I only can't create file...