#1 By: Tony Middleton, February 4th, 2012 09:10
I have just upgraded to Debian squeeze. I used to use autofs to access the backup space over NFS. As part of the upgrade I upgraded to autofs5. When I now try to access the space I get the following message:
Starting automount: /usr/sbin/automount: test mount forbidden or incorrect kernel protocol version, kernel protocol version 5.00 or above required.
Does anyone have a solution to this?
#2 By: Kevin Rutherford, August 1st, 2012 17:11
I get this too. No idea what to do about it...
#3 By: Jamie Lokier, August 6th, 2012 15:54
Judging from the message, perhaps you need to change to a later kernel version in the VM admin screens?
#4 By: Tony Middleton, August 21st, 2012 12:31
I'm running on the Stable-i386 kernel which appears to be 188.8.131.52. A bit surprised that the standard kernel is a little old. What versions are others using?
#5 By: Hamish Dreyer, May 31st, 2013 10:03
I have a similar problem. I also recently upgraded from Squeeze to Wheezy but when I apt-get upgrade it always fails on autofs:
[....] Starting automount.../usr/sbin/automount: test mount forbidden or incorrect kernel protocol version, kernel protocol version 5.00 or above required.
failed (no valid automount entries defined.).
invoke-rc.d: initscript autofs, action "start" failed.
dpkg: error processing autofs (--configure):
subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
E: Sub-process /usr/bin/dpkg returned an error code (1)
As with Tony, I'm using the default Stable-i386 kernel:
# uname -r
Can anyone confirm that switching Kernel will fix this? Which version should I switch to, I don't need any special functionality, just security and stability.
#6 By: Hamish Dreyer, May 31st, 2013 10:33
Just realised that I'm using rsync for moving backups and it still works. So I'm wondering if I can just apt-get remove autofs?
#7 By: Andrew Veitch, June 5th, 2013 18:24
Looking into this, there's a posting on the linux.kernel.autofs list suggesting that you need the autofs4 module to support kernel protocol version 5.00 or above. However, the virtual machine kernels don't appear to support modules.
The same posting suggests that a kernel does not support simultaneous usage of CONFIG_AUTOFS_FS and CONFIG_AUTOFS4_FS, which is what the Stable-i386 kernel appears to be compiled with:
zgrep AUTOFS config.gz
A potential fix might be for the kernel to either be compiled to support modules, or to be compiled with only CONFIG_AUTOFS4_FS set.
For reference: http://comments.gmane.org/gmane.linux.kernel.autofs/4787
#8 By: Simon Ward, August 4th, 2013 12:41
Per https://forum.bytemark.co.uk/comments.php?DiscussionID=3026&page=1#Item_6 the Experimental-i386.kvm kernel has a recent enough version of the autofs4 module enabled. This is currently 3.2.2-kvm-i386-20120306 on my VM.