Comment 8 for bug 996454

I booted into 12.04's recovery mode yesterday to look for some lost disk space that might have been the files that were in the /home folder tree before I moved it to a separate drive. I (incorrectly) did not expect /home to be mounted and when I used the 'mount', 'cat /etc/mtab' and 'df -h' commands to get a few different ways of seeing what was mounted, they showed that only / was mounted, as I expected.

Unfortunately, /home actually *WAS* mounted, but none of the three commands listed above included it in their list. Yet when I ran 'mount -t ext4 /dev/sdb1 /mnt/b' and then ran 'mount' the new drive/mount point WAS listed. If I created a new file in /home, it was immediately visible in /mnt/b as well. This can only mean that /dev/sdb1 was actually mounted on /home as well as /mnt/b even though none of mount, mtab and df showed anything mounted on /home.

This is on a live mail server, but if necessary I can boot into recovery mode again and duplicate the problem, which I would consider to be rather critical. The system tools that report mounted drives should never fail to report something that is actually mounted!