linux-kernel - Re: [PATCH v7 0/7] Add O_DENY* support for VFS and CIFS/NFS

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Date:	Mon, 20 Jan 2014 11:31:13 +0100
From:	Volker Lendecke <Volker.Lendecke@...Net.DE>
To:	Pavel Shilovsky <piastry@...rsoft.ru>
Cc:	Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-cifs <linux-cifs@...r.kernel.org>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	Linux NFS Mailing list <linux-nfs@...r.kernel.org>,
	wine-devel@...ehq.org
Subject: Re: [PATCH v7 0/7] Add O_DENY* support for VFS and CIFS/NFS

On Mon, Jan 20, 2014 at 02:20:43PM +0400, Pavel Shilovsky wrote:
> > One question: If Samba wants to open a file for delete
> > access, there's no corresponding flag in the open
> > permissions. There can be the case where Samba wants to open
> > *just* for future unlink, no read or write access required.
> > Is there a way to achieve this atomically correct?
> 
> You can try to use O_PATH flag. It doesn't give you a delete access
> but should be ok because further deleting will be done without file
> descriptor -- through unlink syscall.

Ok, I did not know about O_PATH. Thanks for that!

So I do an open with O_PATH. How do I then make sure that
nobody else has a O_DENYDELETE set without doing the unlink
itself?

Thanks,

Volker

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