From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [RFC PATCH] fs: allow open(dir, O_TMPFILE|..., 0) with mode 0
Date: Fri, 31 Oct 2014 01:42:20 -0700
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Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Eric Rannaud <e@nanocritical.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
To: Andy Lutomirski <luto@amacapital.net>
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On Thu, Oct 30, 2014 at 05:01:30PM -0700, Andy Lutomirski wrote:
> > flink()), the mode really matters. So this idiotic glibc behavior of
> > only forwarding the third argument if O_CREAT is set seems to be a
> > bug.
> 
> We could bite the bullet and add a tmpfile syscall.   /me ducks

I've got another use case for that:  Samba.  It wants to inherit
all kinds of attributes (xattrs, modes, etc) during file creation,
and right now it's doing it in a racy way.  I've come up with a patch
to use O_TEMPFILE + flink, but it turns out that Samba may as well
be asked to create read-only files, which we can't create using
O_TMPFILE.