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Date:   Mon, 21 Sep 2020 06:28:15 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Andy Lutomirski <luto@kernel.org>
Cc:     Al Viro <viro@zeniv.linux.org.uk>,
        Matthew Wilcox <willy@infradead.org>,
        Christoph Hellwig <hch@lst.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jens Axboe <axboe@kernel.dk>, Arnd Bergmann <arnd@arndb.de>,
        David Howells <dhowells@redhat.com>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
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Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag
Message-ID: <20200921042815.GA16281@lst.de>
References: <20200918124533.3487701-1-hch@lst.de> <20200918124533.3487701-2-hch@lst.de> <20200920151510.GS32101@casper.infradead.org> <20200920180742.GN3421308@ZenIV.linux.org.uk> <CALCETrWHW4wHG+Z-mxsY-kvjSi+S6gRUQ+LHd9syPcm5bhi3cw@mail.gmail.com>
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On Sun, Sep 20, 2020 at 12:14:49PM -0700, Andy Lutomirski wrote:
> I wonder if this is really quite cast in stone.  We could also have
> FMODE_SHITTY_COMPAT and set that when a file like this is *opened* in
> compat mode.  Then that particular struct file would be read and
> written using the compat data format.  The change would be
> user-visible, but the user that would see it would be very strange
> indeed.
> 
> I don't have a strong opinion as to whether that is better or worse
> than denying io_uring access to these things, but at least it moves
> the special case out of io_uring.

open could have happened through an io_uring thread a well, so I don't
see how this would do anything but move the problem to a different
place.

> 
> --Andy
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