Debian – Mounting error with Quota : mount: / not mounted already, or bad option

So I try to activate quota options in /etc/fstab by adding ",usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0" :

before :

# <file system> <mount point>   <type>  <options>       <dump>  <pass>
/dev/sda2       /       ext4    errors=remount-ro,relatime      0       1
/dev/sda3       /home   ext4    defaults,relatime       1       2
/dev/sda4       swap    swap    defaults        0       0
proc            /proc   proc    defaults                0       0
sysfs           /sys    sysfs   defaults                0       0
tmpfs           /dev/shm        tmpfs   defaults        0       0
devpts          /dev/pts        devpts  defaults        0       0

after :

# <file system> <mount point>   <type>  <options>       <dump>  <pass>
/dev/sda2       /       ext4    errors=remount-ro,relatime,usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0      0       1
/dev/sda3       /home   ext4    defaults,relatime       1       2
/dev/sda4       swap    swap    defaults        0       0
proc            /proc   proc    defaults                0       0
sysfs           /sys    sysfs   defaults                0       0
tmpfs           /dev/shm        tmpfs   defaults        0       0
devpts          /dev/pts        devpts  defaults        0       0

But after the modification, I get the following message :

mount -o remount /

mount: / not mounted already, or bad option

Any idea ? This is driving me mad.

EDIT :

Also, I have the following message :

quotacheck -avugm
quotacheck: Cannot stat() mounted device /dev/root: Aucun fichier ou dossier de                                              ce type
quotacheck: Cannot stat() mounted device /dev/root: Aucun fichier ou dossier de                                              ce type
quotacheck: Cannot stat() mounted device /dev/root: Aucun fichier ou dossier de                                              ce type
quotacheck: Cannot stat() mounted device /dev/root: Aucun fichier ou dossier de                                              ce type
quotacheck: Cannot find filesystem to check or filesystem not mounted with quota                                              option.