�Not-fun with reiserfs, or, where did my /home partition go?�
2003-11-17, 13:00:00:

Today we're having this incredible late fall storm that's produced tornadoes and heavy lightning. As the power is wont to do in Houston during a storm, the power bounced and all my computers got restarted, whether I wanted them to or not.

When my Gentoo Linux development server at home came back up, everything looked okay, except for one thing: my /home partition was gone, which sucks because then all my web content was coming up 403 Forbidden because of the directories not being there.

Ouch. Suckage.

I panicked, because my first perusals showed that people just rebuilt the system when these things happened, so I had no idea what to do. However, once I figured that maybe I should replay reiserfs' journal, I had more of a direction.

Of course, you should log in as root or su to gain appropriate rights. Also, below I'm using /home and /dev/sda4 as my examples, but that's just because this is my particular filesystem and device. You should replace it with your particular cases.

The first thing was to see if it was still mounted. Mine wasn't mounted, so I didn't have to unmount it.

Next, the key here is to replay the journal and rebuild the filesystem. Personally, I feel better doing this in three steps, rather than combining them into one operation.

reiserfsck --check /dev/sda4
reiserfsck --rebuild-sb /dev/sda4
reiserfsck --rebuild-tree /dev/sda4

Basically, you replay the journal, then rebuild the superblocks, then rebuild and reindex the filesystem structures. Once this is done, you should have a recognizable filesystem on /dev/sda4 again. If you don't see elements of your filesystem whizzing by as this runs, you may have a bigger problem.

Once this is done, you should mount the filesystem:

mount /dev/sda4 /home

Everything working now? Did for me!

Now if only I can manage to start keeping backups...