"mount -a" mounts cifs shares multiple times

[Peet Whittaker]

This is pretty much a duplicate of this report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=589218

Output of 'grep "cifs" /etc/fstab':

//network/path /mnt/backups cifs dom=xyz,username=xyz,password=xyz,iocharset=utf8,sec=ntlm,vers=3.0 0 0

If I run 'mount -a' and then 'grep "cifs" /etc/mtab' I see 1 entry:

//network/path /mnt/backups cifs rw,relatime,vers=3.0,sec=ntlmssp,cache=strict,username=xyz,domain=xyz,uid=0,noforceuid,gid=0,noforcegid,addr=10.0.0.238,file_mode=0755,dir_mode=0755,nounix,serverino,mapposix,rsize=1048576,wsize=1048576,echo_interval=60,actimeo=1 0 0

However, if I then re-run 'mount -a' and 'grep "cifs" /etc/mtab' I then see 2 (duplicated) entries:

//network/path /mnt/backups cifs rw,relatime,vers=3.0,sec=ntlmssp,cache=strict,username=xyz,domain=xyz,uid=0,noforceuid,gid=0,noforcegid,addr=10.0.0.238,file_mode=0755,dir_mode=0755,nounix,serverino,mapposix,rsize=1048576,wsize=1048576,echo_interval=60,actimeo=1 0 0
//network/path /mnt/backups cifs rw,relatime,vers=3.0,sec=ntlmssp,cache=strict,username=xyz,domain=xyz,uid=0,noforceuid,gid=0,noforcegid,addr=10.0.0.238,file_mode=0755,dir_mode=0755,nounix,serverino,mapposix,rsize=1048576,wsize=1048576,echo_interval=60,actimeo=1 0 0

Running 'mount -a' further times just adds additional duplicate entries into etc/mtab.

This means that in order to un-mount the folder, I have to run 'umount /mnt/backups' multiple times (as many times as it is duplicated in /etc/mtab to be precise).

Adding a trailing slash to the remote network path (i.e. //network/path/) as suggested in the linked bug report makes no difference (I still get duplicated entries in /etc/mtab).

-- SYSTEM INFO --

Description: Ubuntu 16.04.4 LTS
Release: 16.04

Linux 4.4.0-122-generic #146-Ubuntu SMP Mon Apr 23 15:34:04 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

cifs-utils:
  Installed: 2:6.4-1ubuntu1.1
  Candidate: 2:6.4-1ubuntu1.1
  Version table:
 *** 2:6.4-1ubuntu1.1 500
        500 http://gb.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     2:6.4-1ubuntu1 500
        500 http://gb.archive.ubuntu.com/ubuntu xenial/main amd64 Packages