Ceph » CephFS

From mount(8)

       -f, --fake
              Causes  everything  to  be  done except for the actual system call; if it's not obvious, this ``fakes'' mounting the filesystem.  This option is useful in conjunction with the -v flag to determine what the mount command is trying to do.  It can also be used to add entries for devices that were
              mounted earlier with the -n option.  The -f option checks for an existing record in /etc/mtab and fails when the record already exists (with a regular non-fake mount, this check is done by the kernel).

Add a command switch (-f) to the mount helper for this feature.