Debian Bug report logs - #799668
encountering umount.nfs: /mnt: is not an NFS filesystem for vboxsf

Display info messages

Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Shaddy Baddah <beryllium-bugs@shaddybaddah.name>

To: submit@bugs.debian.org

Subject: encountering umount.nfs: /mnt: is not an NFS filesystem for vboxsf

Date: Mon, 21 Sep 2015 22:14:01 +1000

Package: virtualbox-guest-dkms
Version: 4.3.18-dfsg-3+deb8u3
Severity: important
Tags: upstream

As per the subject, since jessie, if I try to umount a vboxsf I
encounter an error:

$ sudo mount -t vboxsf sw /mnt -o ro
$ sudo umount /mnt
umount.nfs: /mnt: is not an NFS filesystem for vboxsf

I've already looked into this. It seems that since jessie, mount
package has changed so that it looks at the f_type member of the struct
statfs, maps to a filesystem label based on the magic no., and then
will use the relevant mount/umount helper, such as umount.nfs here, if
it is available.

Now, I don't necessarily agree with what has been done to the
mount/umount tools, but not knowing if an alternative is easy or
feasible (instead of mapping, using the label that comes out of the
mount output), I think this means that the vboxsf fs module needs to be
a bit cleverer.

I believe the safety blanket afforded by just using NFS_SUPER_MAGIC
f_type (see below) is no longer ok (in fact the line is marked XXX to
indicate something better could be done):

/usr/src/virtualbox-guest-4.3.18/vboxsf/utils.c:841:    stat->f_type  = 
NFS_SUPER_MAGIC; /* XXX vboxsf type? */

I had a look at what open-vm-tools-dkms does here, and even though the
magic number is bogus against /usr/include/linux/magic.h (where mount
find its C defs), it means that no helper is found, and native umount
is performed:

/usr/src/open-vm-tools-9.4.6/vmblock/linux/super.c:139:   stat->f_type = 
VMBLOCK_SUPER_MAGIC;

I propose that we propose this upstream.

-- 
Regards,
Shaddy

-- System Information:
Debian Release: 8.2
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: i386 (i686)

Kernel: Linux 3.16.0-4-586
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages virtualbox-guest-dkms depends on:
ii  dkms                    2.2.0.3-2
ii  dpkg                    1.17.25
ii  virtualbox-guest-utils  4.3.18-dfsg-3+deb8u3

virtualbox-guest-dkms recommends no packages.

virtualbox-guest-dkms suggests no packages.

-- no debconf information

Message #10 received at 799668@bugs.debian.org (full text, mbox, reply):

From: Shaddy Baddah <beryllium-bugs@shaddybaddah.name>

To: 799668@bugs.debian.org

Subject: Re: encountering umount.nfs: /mnt: is not an NFS filesystem for vboxsf

Date: Mon, 21 Sep 2015 22:46:07 +1000

Hi,

On Mon, 21 Sep 2015 22:14:01 +1000 Shaddy Baddah 
<beryllium-bugs@shaddybaddah.name> wrote:
>
> As per the subject, since jessie, if I try to umount a vboxsf I
> encounter an error:
>
> $ sudo mount -t vboxsf sw /mnt -o ro
> $ sudo umount /mnt
> umount.nfs: /mnt: is not an NFS filesystem for vboxsf

I should add that using umount -i (don't call the umount.<type> helpers)
will successfully workaround the problem, and umount the fs.

Also, with the open-vm-tools-dkms example, the magic def looks like:

/usr/src/open-vm-tools-9.4.6/vmblock/linux/filesystem.h:58:#define 
VMBLOCK_SUPER_MAGIC 0xabababab

Which is obviously contrived (they all are I guess), but outside the
kernel provided defines.

Given enough time, I can produce a simple patch, then we would have the
option of raising with upstream, and adding to packages patch list.

-- 
Regards,
Shaddy

Message #15 received at 799668-done@bugs.debian.org (full text, mbox, reply):

From: Andreas Beckmann <anbe@debian.org>

To: 917864-done@bugs.debian.org, 633549-done@bugs.debian.org, 775047-done@bugs.debian.org, 799668-done@bugs.debian.org, 901778-done@bugs.debian.org, 979206-done@bugs.debian.org, 986291-done@bugs.debian.org, 987205-done@bugs.debian.org, 970902-done@bugs.debian.org

Subject: virtualbox-guest-source/virtualbox-guest-dkms have been superseded by the modules included in Linux

Date: Sat, 17 Jun 2023 23:44:27 +0200

Version: 6.1.22-dfsg-3

virtualbox (6.1.22-dfsg-3) unstable; urgency=medium

  [ Dimitri John Ledkov ]
  * Drop virtualbox guest modules dkms and sources, as in Ubuntu and Debian,
    all kernel flavours provide those from the upstream kernel since at least
    focal 20.04 LTS.
    Thus these are not needed anymore. LP: #1933248

 -- Gianfranco Costamagna <locutusofborg@debian.org>  Mon, 19 Jul 2021 09:28:22 +0200

Send a report that this bug log contains spam.