仮想マシンにsshできなくなった（Couldn't remount RDWR because of unprocessed orphan inode list.）

VirtualBox + Vagrant でローカルにいくつか仮想マシンを立てているのですが、その内1つが壊れたので対応メモ。 先日VirtualBoxをアップデートしたのでそれが原因かは不明。

手元の環境

$ virtualbox -h
Oracle VM VirtualBox Manager 5.0.8
(C) 2005-2015 Oracle Corporation
All rights reserved.

$ vagrant --version
Vagrant 1.7.4

現象

$ vagrant reload
==> default: Attempting graceful shutdown of VM...
    default: Guest communication could not be established! This is usually because
    default: SSH is not running, the authentication information was changed,
    default: or some other networking issue. Vagrant will force halt, if
    default: capable.
==> default: Forcing shutdown of VM...
==> default: Clearing any previously set forwarded ports...
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
    default: Adapter 1: nat
    default: Adapter 2: hostonly
==> default: Forwarding ports...
    default: 22 => 2222 (adapter 1)
==> default: Running 'pre-boot' VM customizations...
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address: 127.0.0.1:2222
    default: SSH username: vagrant
    default: SSH auth method: private key
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
    default: Warning: Connection timeout. Retrying...
Timed out while waiting for the machine to boot. This means that
Vagrant was unable to communicate with the guest machine within
the configured ("config.vm.boot_timeout" value) time period.

If you look above, you should be able to see the error(s) that
Vagrant had when attempting to connect to the machine. These errors
are usually good hints as to what may be wrong.

If you're using a custom box, make sure that networking is properly
working and you're able to connect to the machine. It is a common
problem that networking isn't setup properly in these boxes.
Verify that authentication configurations are also setup properly,
as well.

If the box appears to be booting properly, you may want to increase
the timeout ("config.vm.boot_timeout") value.

原因

不幸中の幸いで、VirtualBoxを起動してコンソールは開けたのでvagrantユーザーでログインしてみたら、read-only file system みたいな警告が出てた。 sudo service restart sshd しても同じ警告で can not remove file みたいなことを言われたのでこれっぽい。

対応

http://superuser.com/questions/947942/unprocessed-orphan-inode-list-in-virtualbox-vm

$ sudo umount /dev/sda1
$ fsck /dev/sda1