From: Karel Zak <kzak@redhat.com>
To: Phillip Susi <psusi@ubuntu.com>
Cc: util-linux@vger.kernel.org
Subject: Re: read only bind mount ignores ready only
Date: Wed, 11 Dec 2013 17:49:30 +0100 [thread overview]
Message-ID: <20131211164930.GC16572@x2.net.home> (raw)
In-Reply-To: <52A878C5.6050505@ubuntu.com>
On Wed, Dec 11, 2013 at 09:37:57AM -0500, Phillip Susi wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Forwarding report from
> https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/712892
>
> It seems that the kernel has a bug where it silently ignores the
> MS_RDONLY flag when creating a bind mount. mount issues a warning
Yes, this is known issue.
> that the mount point appears to be read-write even though you
I think that libmount based mount does not warn about it (mistake?).
> requested read only. The reporter suggests a patch to automatically
> attempt to remount with MS_RDONLY before issuing this warning to work
> around the kernel bug. What do you think?
Well, it means that the kernel disadvantage will never be fixed ;-)
It would be relatively simple to fix it, because libmount already
support "additional mounts" to implement things like
mount --make-private /dev/sda1 /mnt
(kernel does not allow to use propagation flags for regular mount
operation). I'll try it tomorrow.
The problem is that all these userspace hacks does not atomic...
Karel
--
Karel Zak <kzak@redhat.com>
http://karelzak.blogspot.com
next prev parent reply other threads:[~2013-12-11 16:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-11 14:37 read only bind mount ignores ready only Phillip Susi
2013-12-11 16:49 ` Karel Zak [this message]
2013-12-12 12:05 ` Karel Zak
2013-12-12 14:59 ` Phillip Susi
2013-12-12 16:02 ` Karel Zak
2013-12-12 19:42 ` Miklos Szeredi
2013-12-12 21:53 ` Al Viro
2013-12-13 10:45 ` Karel Zak
2013-12-13 8:18 ` Karel Zak
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