Cannot unmount shared folder after upgrade to Debian jessie

[seberoon]

I recently upgraded a Debian guest from 7 (wheezy) to 8 (jessie).

I can successfully mount shared folders like so:

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> mount -t vboxsf seb /media/sf_seb

But I am unable to unmount them:

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> umount /media/sf_seb
umount.nfs: /media/sf_seb: is not an NFS filesystem

I also tried with option "-t vboxsf" but same result. Any ideas as to cause?

Some stuff which might be relevant:
VirtualBox Version 5.0.10 r104061
I had to reinstall guest additions.
At boot time I see the message "failed to start vboxadd-service.service" and syslog shows:

syslog extract

vboxsf.tiff (11.97 KiB) Viewed 17842 times

[Perryg]

It appears you are using automount and as such the share is considered removable media and not a mount/umount device. Either shut down the guest and remove the share than create the share *not automount and use the mount/umount in the guest or reboot the guest to refresh the automount share.

[seberoon]

Thanks for the suggestion but no, I'm mounting manually, so I don't think that can be it. Maybe you thought that because I was mounting under /media?

Anyway, just to be sure, I shut down the guest, removed the shared folder and re-created it in the VB manager (making sure not to tick the automount option), rebooted the guest and manually mounted under /mnt. Same behaviour as before; I cannot unmount. (I also looked for /etc/auto.* config files on the guest, to see if I could spot anything suspicious, but there are none.)

[Perryg]

Post the guests log file ( as an attachment ). Right click on the guest in the Main Manager then click show log. Save and post as an attachment. Compress if it is too large to post.

[seberoon]

Attached as requested.

[Perryg]

Log shows a good share and that it is accepted. This is going to point at the guest.

Your umount statement "umount.nfs: /media/sf_seb: is not an NFS filesystem" looks suspicious to me. I would look at the dmesg and syslog of the guest to make sure that the vboxsf service is actually loading. You can also look at the /var/log/vboxadd-install.log for answers as to whether the guest additions installed correctly.

[seberoon]

The install log looks good (attached).
dmesg looks good (attached).
But there are some troublesome looking messages in syslog (attached), in particular:

Dec 4 15:39:02 bigears vboxadd[595]: Starting the VirtualBox Guest Additions ...done.
Dec 4 15:39:02 bigears kernel: [ 18.216101] vboxsf: Successfully loaded version 5.0.10 (interface 0x00010004)
Dec 4 15:39:02 bigears saned[689]: saned disabled; edit /etc/default/saned.
Dec 4 15:39:02 bigears vboxadd-service[701]: Starting VirtualBox Guest Addition service ...done.
Dec 4 15:39:02 bigears systemd[1]: vboxadd-service.service: control process exited, code=exited status=1
Dec 4 15:39:02 bigears systemd[1]: Failed to start vboxadd-service.service.
Dec 4 15:39:02 bigears systemd[1]: Unit vboxadd-service.service entered failed state.

Any suggestions?

[Perryg]

I would purge VirtualBox from the guest, reboot, and install a fresh copy. I have seen a corrupt install when upgrading a distro before. Normally I install a new instance and keep all data on a second partition so it is retained. I also set the home folder to a separate partition so all of my configurations are retained.

[seberoon]

Could you amplify a bit what you mean by "purge VirtualBox from the guest"? I uninstalled the guest additions by running

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/opt/VBoxGuestAdditions-5.0.10/uninstall.sh

and then reinstalled, but it made no difference. I'm guessing you mean something more comprehensive.

[Perryg]

You need to uninstall like you did and then check to see if there are any other versions or remnants of older installs. I normally do this from CLI and use apt-get purge ... to make sure that it is all clean.

[Perryg]

To clarify a bit more the real issue seems to be the move from init.d to systemd and the configurations that are left in rc when this happens.

[seberoon]

I found vestiges of three virtualbox packages, purged them and resinstalled guest additions, as suggested. This seems to have made the worrying syslog messages go away. Unfortunately I still cannot unmount shared folders! Oh well.

Giving up for now. Thanks for all your help.

[seberoon]

UPDATE: according to this Debian bug report
https://bugs.debian.org/cgi-bin/bugrepo ... bug=799668,
the underlying issue is an incompatibility between vboxsf and Jessie's mount package. The workaround is to use

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umount -i

.

[Symmer]

Can you try out these steps??

This worked for me to unmount


> mount -t vboxsf SHARED_FOLDER_NAME /media/sf_seb


after you are done working with the sharing folder (available in the /media/sf_seb)

unmounting can be performed this way

>umount -t vboxsf SHARED_FOLDER_NAME

or

>umount /media/sf_seb



I hope it was not against the question that was raised.


tested in virtualbox 5.1.8 with windows 7 host and linux centos guest.

[nagu]

'umount -i' worked for me. host os is win7 guest os is archlinux. thanks @seberoon.