Please note the following points when you use the Mount namespace function.
Do not mount or unmount the GFS Shared File System in a process whose mount namespace is unshared.
Do not unmount the GFS Shared File System if there is a process which mounts it as private mount.
Use the following method to check if there is a process which mounts the GFS Shared File System as private mount.
# grep "\- sfcfs" /proc/*/mountinfo | egrep -v "shared:|master:" # |
If nothing is output, there is no process which mounts the GFS Shared File System as private mount.