When there is problem with your EBS Volume, you can try detach the root device, attaching it to another device and access it to fix it.

To attach: mount /dev/xvdf /vol
To detach: umount /vol
where /vol is the mount point

When you want to re-attach a root device, you have to set the device name to
/sda1 instead of the default name /sdf

If error when trying to mount EBS:

mount: wrong fs type, bad option, bad superblock on /dev/xvdf,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so

sudo mount /dev/xvdf /vol -t ext4 or sudo mount /dev/xvdf1 /vol -t ext4

Filesystem check: fsck

If any settings wrong, it’s in /etc/fstab