Full hard drive causes xorg and lightdm to fail to load

[Rick Spencer]

Steps:
1. Have a computer with default partioning
2. Fill the drive with data
3. reboot

Result
You are forced into low graphics mode and when you log in, the desktop session won't start

Expected
You can log in and use the desktop

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: mountall 2.33
ProcVersionSignature: Ubuntu 3.2.0-15.24-generic 3.2.5
Uname: Linux 3.2.0-15-generic x86_64
ApportVersion: 1.91-0ubuntu1
Architecture: amd64
Date: Wed Feb 15 09:57:15 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110919)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: mountall
UpgradeStatus: Upgraded to precise on 2012-01-14 (31 days ago)

[Martin Pitt (pitti)]

In earlier versions our sysvinit scripts mounted a tmpfs on /tmp if there was less than 1 MB free. I think we lost this. We should either consider making /tmp a tmpfs all the time, or at least bring back this fallback mode.

[Martin Pitt (pitti)]

When /home is full, the session will fail to start. This is covered by bug 35217 [sic, five-digit]. But we should at least get lightdm to start properly, so that you can start a reduced session.

[Martin Pitt (pitti)]

There are two parts to this:

 - Somewhere in the upstartification we lost the emergency mounting of an 1 MB /tmp tmpfs if /tmp had less than 1 MB of free space. This is in mountall, I'm working on this.

- lightdm cannot write /var/lib/lightdm/.Xauthority as user "lightdm" when the disk has less than 5% free space (i. e. it counts as "full" for users). Here it would help if lightdm wrote its .Xauthority file somewhere into /run/. Robert, does it actually need to be permanent across reboots?

[Launchpad Janitor (janitor)]

This bug was fixed in the package mountall - 2.35

---------------
mountall (2.35) precise; urgency=low

  * conf/mounted-tmp.conf: Mount an 1 MiB tmpfs on /tmp/ if /tmp has less than
    1 MB of space, so that booting has a chance of succeeding with a full
    disk. Ubuntu up to 8.04 LTS already had this, but this got lost in
    between. (LP: #932598)
 -- Martin Pitt <email address hidden> Thu, 08 Mar 2012 11:57:29 +0100

[Martin Pitt (pitti)]

Robert, there is currently no special code to handle /var/lib/lightdm/.Xauthority, it's handled by the same code as for any other user session. Would it be possible to make a special case there, so that the greeter uses /run/lightdm/.Xauthority, and every other user session uses ~/.Xauthority, as usual?

If not, we could think about shipping a /var/lib/lightdm/.Xauthority -> /run/lightdm/.Xauthority symlink.

In either case, either lightdm itself or the upstart job needs to create /run/lightdm/ at startup with the right permissions.

[Robert Ancell (robert-ancell)]

Seems like a good idea to stop the greeter X authority in /run (the X server authority is currently stored there).

[Steve Langasek (vorlon)]

The Precise Pangolin has reached end of life, so this bug will not be fixed for that release