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

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Message-ID: <CAKywueQng9=u1YYwkYGCunWW8RBhARhJjEhBcoA6CKF6TrKSBg@mail.gmail.com>
Date:	Tue, 21 Jan 2014 17:31:39 +0400
From:	Pavel Shilovsky <piastry@...rsoft.ru>
To:	"Volker.Lendecke@...Net.DE" <Volker.Lendecke@...net.de>
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

2014/1/20 Volker Lendecke <Volker.Lendecke@...net.de>:
>> 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?

It's not possible with the current API to do it through open syscall.
Another possibility is to look at /proc/locks. But I think we really
need O_DELETE flag that will force a file to be removed on close - we
will be able to do O_DENYDELETE checks atomically.

-- 
Best regards,
Pavel Shilovsky.
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