Arch Linux

P_Daddy

Member

Registered: 2019-07-08

Posts: 5

Mount Virtualbox shared folders in /etc/fstab

I have a Virtualbox VM running Arch Linux (the host is also Arch, incidentally).

I'm trying to automatically mount some shared folders in some specific locations using /etc/fstab.  I do not want them mounted in Virtualbox's default /media/sf_whatever paths.

I have the following entries in /etc/fstab:

srv      /srv                vboxsf  gid=109,suid,fmode=664,nofail                 0  0
share2   /share2             vboxsf  gid=109,suid,fmode=664,nofail                 0  0
p_daddy  /home/p_daddy/host  vboxsf  uid=1000,gid=1000,noauto,x-systemd.automount  0  0

Group 109 is vboxsf.

The mount in my user directory isn't necessary unless I try to use it, so it's set to noauto, and x-systemd.automount causes it to get mounted the first time I access it.  That works beautifully.

The other two mounts don't work so well.  For the record, I've tried replacing nofail with the same noauto,x-systemd.automount options I've used on the p_daddy share, but if I do that, when I try to access the mount points, I get "no such device" every time.

With /etc/fstab as above, the srv and share2 mounts simply fail:

$ journalctl -u srv.mount
...
-- Reboot --
Jul 08 16:04:39 Joker systemd[1]: Mounting /srv...
Jul 08 16:04:39 Joker mount[260]: mount: /srv: mount(2) system call failed: No such file or directory.
Jul 08 16:04:39 Joker systemd[1]: srv.mount: Mount process exited, code=exited, status=32/n/a
Jul 08 16:04:39 Joker systemd[1]: srv.mount: Failed with result 'exit-code'.
Jul 08 16:04:39 Joker systemd[1]: Failed to mount /srv.

But what's weird is that after I log in, I can execute sudo mount -a and /srv and /share2 are mounted successfully.

So I figured maybe the right kernel modules just aren't loaded yet when the mount units run.  I figured I'd hack around that by adding a service that retried the mounts once most things are up and running:

$ cat /etc/systemd/system/retry-missed-mounts.service 
[Unit]
Description=Retry mounts that failed during boot
Wants=network-online.target
After=network-online.target

[Service]
Type=oneshot
ExecStart=/bin/mount -a

[Install]
WantedBy=multi-user.target

But that fails:

$ journalctl -u retry-missed-mounts.service
...
Jul 08 16:04:40 Joker mount[336]: mount: /srv: mount(2) system call failed: No such file or directory.
Jul 08 16:04:40 Joker mount[336]: mount: /share2: mount(2) system call failed: No such file or directory.

Even if I try restarting the service after I've logged in:

$ sudo systemctl restart retry-missed-mounts.service
Job for retry-missed-mounts.service failed because the control process exited with error code.
See "systemctl status retry-missed-mounts.service" and "journalctl -xe" for details.
$ journalctl -u retry-missed-mounts.service
...
Jul 08 16:08:12 Joker mount[424]: mount: /srv: mount(2) system call failed: No such file or directory.
Jul 08 16:08:12 Joker mount[424]: mount: /share2: mount(2) system call failed: No such file or directory.

But again, running the same mount -a command manually works fine.

$ sudo mount -a
$ ls /srv
some stuff in there
$ ls /share2
some more stuff in there

Any idea why the mounts would fail when run by systemctl but not with sudo?  Any idea on a workaround?

loqs

Member

Registered: 2014-03-06

Posts: 19,057

Re: Mount Virtualbox shared folders in /etc/fstab

Please see https://bugs.archlinux.org/task/61307#comment179937
Edit:
Oh and welcome to the arch linux forums P_Daddy.

Last edited by loqs (2019-07-08 20:32:42)

P_Daddy

Member

Registered: 2019-07-08

Posts: 5

Re: Mount Virtualbox shared folders in /etc/fstab

A patch to a patch.  That's fun to read.  :-)

Do you know, does this fix mounting with fstab in addition to Virtualbox's /media/sf_whatever automounter?

Also, this bug report is several months old and low priority.  Is my best bet to apply this patch manually?  Because I'm not sure how.

loqs

Member

Registered: 2014-03-06

Posts: 19,057

Re: Mount Virtualbox shared folders in /etc/fstab

I believe it fixes fstab mounting as well.  Download the src.tar.gz then

bsdtar -xf virtualbox-6.0.8-2.src.tar.gz
pacman -S devtools # needed to build in a clean chroot
cd virtualbox
multilib-build #builds the package in a clean chroot needs to be multilib for dev86
pacman -U virtualbox-guest-utils-6.0.8-2-x86_64.pkg.tar.xz

P_Daddy

Member

Registered: 2019-07-08

Posts: 5

Re: Mount Virtualbox shared folders in /etc/fstab

Thanks for the reply, loqs, and sorry it took me a while to try it out.  Unfortunately, it didn't seem to make a difference.