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Date: Fri, 12 Apr 2024 08:44:21 +0200
From: Christian Brauner <brauner@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Charles Mirabile <cmirabil@redhat.com>, 
	Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>, linux-fsdevel@vger.kernel.org, 
	linux-kernel@vger.kernel.org, Andrew Lutomirski <luto@kernel.org>, Peter Anvin <hpa@zytor.com>
Subject: Re: [PATCH] vfs: relax linkat() AT_EMPTY_PATH - aka flink() -
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On Thu, Apr 11, 2024 at 11:13:53AM -0700, Linus Torvalds wrote:
> On Thu, 11 Apr 2024 at 10:35, Charles Mirabile <cmirabil@redhat.com> wrote:
> >
> > And a slightly dubious addition to bypass these checks for tmpfiles
> > across the board.
> 
> Does this make sense?
> 
> I 100% agree that one of the primary reasons why people want flink()
> is that "open tmpfile, finalize contents and permissions, then link
> the final result into the filesystem".
> 
> But I would expect that the "same credentials as open" check is the
> one that really matters.

Yes. There's no need to give O_TMPFILE special status there. We also end
up with a collection of special-cases which is just unpleasant.