From: Christoph Hellwig <hch@lst.de>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: Dave Chinner <david@fromorbit.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Brian Foster <bfoster@redhat.com>, Christoph Hellwig <hch@lst.de>,
Eric Sandeen <sandeen@redhat.com>,
linux-xfs <linux-xfs@vger.kernel.org>
Subject: Re: [PATCH, RFC] xfs: re-enable FIBMAP on reflink; disable for swap
Date: Sat, 1 Sep 2018 10:32:17 +0200 [thread overview]
Message-ID: <20180901083217.GD670@lst.de> (raw)
In-Reply-To: <19b4da59-3720-6647-e557-9d7353ed509b@sandeen.net>
On Fri, Aug 31, 2018 at 08:08:11AM -0500, Eric Sandeen wrote:
> If you can directly read the block device hosting the files, file
> permissions of shared blocks are completely beside the point.
The point is that you should never, ever directly read blocks from
the block device, nevermind write. And we need to make sure userspace
stops doing that instead of catering to it in any way.
> The "typical use case" is to map a file for a bootloader to /read/
> at boot, and our arbitrary restriction has broken systems in
> the real world, and burned a lot of institutional effort getting
> to the bottom of the problem and working around it.
And even that 'use case' is utterly broken.
next prev parent reply other threads:[~2018-09-01 12:40 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-30 16:10 [PATCH, RFC] xfs: re-enable FIBMAP on reflink; disable for swap Eric Sandeen
2018-08-30 16:25 ` Christoph Hellwig
2018-08-30 16:31 ` Eric Sandeen
2018-08-30 16:36 ` Christoph Hellwig
2018-08-30 16:35 ` Eric Sandeen
2018-08-30 18:02 ` Brian Foster
2018-08-30 18:28 ` Darrick J. Wong
2018-08-30 18:51 ` Eric Sandeen
2018-08-30 19:39 ` Brian Foster
2018-08-30 19:47 ` Eric Sandeen
2018-08-30 19:58 ` Brian Foster
2018-08-31 0:11 ` Dave Chinner
2018-08-31 1:34 ` Eric Sandeen
2018-08-31 3:05 ` Dave Chinner
2018-08-31 13:08 ` Eric Sandeen
2018-09-01 8:32 ` Christoph Hellwig [this message]
2018-08-31 6:28 ` Christoph Hellwig
2018-08-31 12:36 ` Brian Foster
2018-09-01 8:31 ` Christoph Hellwig
2018-09-02 14:08 ` Carlos Maiolino
2018-09-02 17:52 ` Eric Sandeen
2018-09-03 10:21 ` Carlos Maiolino
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