This month's disaster involves a trashed filesystem. To create the disaster, boot up UML with a COW-ed or copied root filesystem, and zero out the root filesystem's superblock:

dd if=/dev/zero of=/dev/ubd/0 seek=1 bs=1024 count=1

You will then get all kinds of nasty-loooking stuff in the kernel log such as:

                
EXT2-fs error (device ubd(98,0)): ext2_write_inode: bad inode number: 50571
EXT2-fs error (device ubd(98,0)): ext2_write_inode: bad inode number: 33108
EXT2-fs error (device ubd(98,0)): ext2_write_inode: bad inode number: 32987
EXT2-fs error (device ubd(98,0)): ext2_write_inode: bad inode number: 33165
EXT2-fs error (device ubd(98,0)): ext2_write_inode: bad inode number: 33112
EXT2-fs error (device ubd(98,0)): ext2_write_inode: bad inode number: 34175
EXT2-fs error (device ubd(98,0)): ext2_new_block: block(1006) >= blocks count(0) - block_group = 0, es == a0a8c400 
EXT2-fs error (device ubd(98,0)): ext2_new_block: block(1116) >= blocks count(0) - block_group = 0, es == a0a8c400 

              

You can try running halt, but it probably won't work, so shut it down with the mconsole instead:

                
(debian) sysrq u
OK 
(debian) halt
OK 

              

Your mission, should you choose to accept it, is to restore this filesystem to health.