On CentOS7 df shows not correct data about /dev/vdb

# df

Filesystem 1K-blocks Used Available Use% Mounted on

/dev/mapper/centos-root 13105152 2695388 10409764 21% /

devtmpfs 8140264 0 8140264 0% /dev

tmpfs 8150940 0 8150940 0% /dev/shm

tmpfs 8150940 839576 7311364 11% /run

tmpfs 8150940 0 8150940 0% /sys/fs/cgroup

/dev/vdb 515928320 786176 488911360 1% /home

/dev/vda1 508580 180304 328276 36% /boot

tmpfs 1630192 0 1630192 0% /run/user/0

With /etc/fstab I set as following.

UUID=f3b3a4ae-757f-4c68-bbbe-c05ded3d8580 /mnt/extradiskA ext4 defaults,usrquota,grpquota 1 2

/dev/mapper/centos-swap swap swap defaults 0 0

/mnt/extradiskA/home /home none bind 0 0

/mnt/extradiskA/log /var/log none bind 0 0

/mnt/extradiskA/mysql /var/lib/mysql none bind 0 0

/mnt/extradiskA/.backup /.backup none bind 0 0

/mnt/extradiskA/.daily_backup /.daily_backup none bind 0 0

So, df must show like following.

/dev/vdb 515928320 xxxxx xxxxxx xx% /mnt/extradiskA

Please tell me how I can fix this problem.

Tadao