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Date: Mon, 3 Nov 2014 09:05:51 -0800
Message-ID: <CA+55aFz_C4nVX580nvvAngsB3U9oMnCGPDs8Yo1Qpx=XagcpMA@mail.gmail.com>
Subject: Re: [RFC PATCH] fs: allow open(dir, O_TMPFILE|..., 0) with mode 0
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>, Al Viro <viro@zeniv.linux.org.uk>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Eric Rannaud <e@nanocritical.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>
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On Mon, Nov 3, 2014 at 12:34 AM, Christoph Hellwig <hch@infradead.org> wrote:
>
> That doesn't help because we explicitly reject O_RDONLY when combined
> with O_TMPFILE.

You obviously cannot actually have a read-only file descriptor with
O_TMPFILE, unless all you care about is a zero-sized file with no
contents.

That's why people are talking about things like downgrading the file
*after* filling it, using sealing.

                  Linus
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