rm: cannot remove '/boot/initrd.img-*': Structure needs cleaning [duplicate]

Your file system is broken. You need to fix it so that your OS can properly read/write it.

Therefore, we need to utilise a tool named fsck.

As per it's man page:

Name

fsck - check and repair a Linux file system

Synopsis

fsck [-sAVRTMNP] [-C [fd]] [-t fstype] [filesys...] [--] [fs-specific-options]

Description

fsck is used to check and optionally repair one or more Linux file systems. filesys can be a device name (e.g. /dev/hdc1, /dev/sdb2), a mount point (e.g. /, /usr, /home), or an ext2 label or UUID specifier (e.g. UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd or LABEL=root). Normally, the fsck program will try to handle filesystems on different physical disk drives in parallel to reduce the total amount of time needed to check all of the filesystems.

A basic usage of the command would be:

sudo fsck.ext4 /dev/sda[NUMBER]

However, do note that this process can be a lengthy one.

Just as written, you can clean the partition (after a backup, as you already did), by typing

sudo e2fsck /dev/dm-4

e2fsck checks the file system's integrity.

Afterwards, you should be able to mount it again.