I am trying to figure out why mount -a is not detecting an already mounted DFS share endpoint. It works as expected on mount.cifs version 5.5 but not 6.7 Distributor ID: Debian Description: Debian GNU/Linux 9.13 (stretch) Release: 9.13 Codename: stretch Mount.cifs version 6.7. /etc/fstab //ctserver6/ops_apps /mnt/ops_apps cifs defaults,credentials=/root/.smbcredentials,rw,users,_netdev,soft 0 0 //ctserverbc/Public /mnt/ctserverbc cifs defaults,credentials=/root/.smbcredentials,rw,users,_netdev,soft 0 0 #//ctserver3/ops /mnt/ops cifs defaults,credentials=/root/.smbcredentials,rw,users,_netdev,soft 0 0 #//ctserver3/public /mnt/public cifs defaults,credentials=/root/.smbcredentials,rw,users,_netdev,soft 0 0 //ctdomain.local/DFS_OPS/OPS /mnt/ops cifs vers=2.1,credentials=/root/.smbcredentials,rw,users,_netdev,soft 0 0 //ctdomain.local/DFS_OPS/Public /mnt/public cifs vers=2.1,credentials=/root/.smbcredentials,rw,users,_netdev,soft 0 0 If I leave off the vers=2.1 option it will create a new mount process and duplicate in /proc/mounts : /mnt/ops_apps : already mounted /mnt/ctserverbc : already mounted mount.cifs kernel mount options: ip=192.168.111.10,unc=\\ctdomain.local\DFS_OPS,soft,user=ctlinux,prefixpath=OPS,pass=******** /mnt/ops : successfully mounted mount.cifs kernel mount options: ip=192.168.111.20,unc=\\ctdomain.local\DFS_OPS,soft,user=ctlinux,prefixpath=Public,pass=******** /mnt/public : successfully mounted With vers=2.1 I get: /mnt/ops_apps : already mounted /mnt/ctserverbc : already mounted mount.cifs kernel mount options: ip=192.168.111.20,unc=\\ctdomain.local\DFS_OPS,vers=2.1,soft,user=ctlinux,prefixpath=OPS,pass=******** mount error(16): Device or resource busy Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) mount.cifs kernel mount options: ip=192.168.111.20,unc=\\ctdomain.local\DFS_OPS,vers=2.1,soft,user=ctlinux,prefixpath=Public,pass=******** mount error(16): Device or resource busy Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) On 5.5 it will detect the DFS share is mounted already -- Chris Pickett | Linux Systems Engineer
The result is duplicate mount processes created for every mount -a attempted. We had a cron that was calling mount -a every 5 min so we were building up quite a few entries in /proc/mounts.
What is the kernel version on the two (the failing and working kernels)?
The kernel version is the same on both systems. They are LCX containers running on Proxmox kernel version 4.15.18-30-pve. However, they are on separate hypervisors.