I have a client /etc/fstab mount for an NFS volume (/data2 on ftgme2) which by mistake was dropped from /etc/exports on the server.  However, the mount on the client system seems to be in a partial state.

As demonstated below, "mount" thinks it's mounted, "df" thinks it's not, and file managers like Dolphin see the directory as empty.  Looking at journalctl, systemd thinks the mount succeeded just as the others.

[root@jaglap ~]# cat /etc/fstab
# Entry for /dev/sda5 :
UUID=7e05faea-eeab-4cc8-90b1-d45997dcb2b8 / ext4 noatime,acl 1 1
# Entry for /dev/sda9 :
UUID=4808af99-1da1-4599-87c1-bc12e1a7daac /data ext4 noatime,acl 1 2
# Entry for /dev/sda10 :
UUID=beca5ca3-ae29-4f74-a5c4-df2a8d36e94f /mnt/VirtualBox ext4 noatime,acl 1 2
none /proc proc defaults 0 0
# Entry for /dev/sda8 :
UUID=acc35c32-0f8f-4eca-bc90-d9d137bcd848 /usr/local ext4 noatime,acl 1 2
# Entry for /dev/sda7 :
UUID=811a1372-ab79-49f3-a6fa-d79cfa177ea1 swap swap defaults 0 0
ftgme2:/          /mnt/ftgme2 nfs rw,bg,soft 0 0
ftgme2:/data      /mnt/ftgme2.data nfs rw,bg,soft 0 0
ftgme2:/data2     /mnt/ftgme2.data2 nfs rw,bg,soft 0 0
ftgme2:/usr/local /mnt/ftgme2.usr.local nfs rw,bg,soft 0 0
ftgfiles1:/mnt/cauldron  /mnt/cauldron nfs rw,bg,soft 0 0

[root@jaglap ~]# mount | grep data2
ftgme2://data2 on /mnt/ftgme2.data2 type nfs4 (rw,relatime,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,soft,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.3.114,local_lock=none,addr=192.168.3.102)

[root@jaglap ~]# df
Filesystem               Size  Used Avail Use% Mounted on
/dev/sda5                 30G   25G  3.7G  87% /
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    1.9G  1.4M  1.9G   1% /dev/shm
tmpfs                    1.9G 1000K  1.9G   1% /run
tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup
tmpfs                    1.9G  208K  1.9G   1% /tmp
/dev/sda8                7.8G  7.2G  166M  98% /usr/local
/dev/sda9                126G   48G   72G  40% /data
/dev/sda10                93G   51G   38G  58% /mnt/VirtualBox
tmpfs                    1.9G 1000K  1.9G   1% /var/spool/postfix/run/saslauthd
ftgme2:/                  40G   20G   19G  52% /mnt/ftgme2
ftgme2:/usr/local         16G  7.2G  7.7G  49% /mnt/ftgme2.usr.local
ftgme2:/data             252G  157G   83G  66% /mnt/ftgme2.data
ftgfiles1:/mnt/cauldron  104G   92G  6.3G  94% /mnt/cauldron
[root@jaglap ~]# mount /mnt/ftgme2.data2
mount.nfs: /mnt/ftgme2.data2 is busy or already mounted
[root@jaglap ~]# 

After correcting /etc/exports, umount/mount works correctly.

The problem appears to be that mount doesn't realize that the mount failed.

Reproducible: 

Steps to Reproduce: