Montando permanentemente um diretório com LVM

Eu montei com sucesso um diretório para outro caminho:

[michael@vps ~]$ mkdir /home/michael/devicefilexxx
[michael@vps ~]$ mkdir /home/michael/mountpointxxx
[michael@vps ~]$ sudo mount --bind /home/michael/devicefilexxx /home/michael/mountpointxxx

Eu vejo como fica:

[michael@vps ~]$ cat /etc/mtab | grep xxx
/dev/mapper/centos-root /home/michael/mountpointxxx xfs rw,relatime,attr2,inode64,noquota 0 0

Bem, o ponto de montagem parece correto, mas não o dispositivo. Eu especifiquei o dispositivo como /home/michael/devicefilexxx, não /dev/mapper/centos-root. Então eu olho um pouco mais fundo:

[michael@vps ~]$ mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
devtmpfs on /dev type devtmpfs (rw,nosuid,size=1009596k,nr_inodes=252399,mode=755)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,nodev,mode=755)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
cgroup on /sys/fs/cgroup/pids type cgroup (rw,nosuid,nodev,noexec,relatime,pids)
cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_prio,net_cls)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpuacct,cpu)
cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb)
configfs on /sys/kernel/config type configfs (rw,relatime)
/dev/mapper/centos-root on / type xfs (rw,relatime,attr2,inode64,noquota)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=34,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
mqueue on /dev/mqueue type mqueue (rw,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
/dev/sda1 on /boot type xfs (rw,relatime,attr2,inode64,noquota)
tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,size=204060k,mode=700,uid=1000,gid=1000)
/dev/mapper/centos-root on /home/michael/mountpointxxx type xfs (rw,relatime,attr2,inode64,noquota)

Hmm, dois dispositivos no mesmo ponto de montagem? Então, eu olho para o meu /etc/fstab:

[michael@vps ~]$ cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Fri Apr  8 14:15:42 2016
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        1 1
UUID=362355d4-e5da-44de-bf5c-5ce92cf43888 /boot                   xfs     defaults        1 2
/dev/mapper/centos-swap swap                    swap    defaults        0 0

Se eu quiser tornar a montagem persistente após a reinicialização da máquina, certamente não gostaria de adicionar o seguinte a /etc/stab:

/dev/mapper/centos-root /home/michael/mountpointxxx xfs rw,relatime,attr2,inode64,noquota 0 0

Talvez o seguinte, mas hesito em fazê-lo, pois difere do que /etc/mtabme disse:

/home/michael/devicefilexxx /home/michael/mountpointxxx xfs rw,relatime,attr2,inode64,noquota 0 0

Como alguém monta permanentemente um diretório/arquivo? Além disso, explique como /dev/mapper/centos-rootpode haver dois pontos de montagem que são obviamente diferentes, portanto, devem ser montados em dispositivos diferentes.

EDITAR. Informações de backup:

[michael@vps ~]$ lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0   80G  0 disk
├─sda1            8:1    0  500M  0 part /boot
└─sda2            8:2    0 79.5G  0 part
  ├─centos-swap 253:0    0    2G  0 lvm  [SWAP]
  └─centos-root 253:1    0 77.5G  0 lvm  /
sr0              11:0    1 1024M  0 rom
[michael@lsblk ~]$