Ubuntu Manpage: mount.lockfs - helper script for the mount command

Provided by: bilibop-lockfs_0.4.20_amd64

NAME

       mount.lockfs - helper script for the mount command

SYNOPSIS

       mount.lockfs FILESYSTEM MOUNTPOINT -o MOUNTOPTIONS

DESCRIPTION

/sbin/mount.lockfs is a symlink to /lib/bilibop/lockfs_mount_helper. It is used as an
helper program by the mount(8) command for the 'lockfs' filesystem type entries in
/etc/fstab. This script cannot be run manually, and fails if the root filesystem is not
already managed by bilibop-lockfs. The expected way to run it and how it does its job are
the followings:

1. Enable bilibop-lockfs: set the BILIBOP_LOCKFS variable to true in bilibop.conf(5) and
reboot the computer; or reboot the computer and append the 'lockfs' kernel parameter to
the boot commandline.

2. One time the future '/' is set as an aufs(5) mountpoint from into the initramfs
environment, the temporary and writable fstab(5) on it is modified to replace
filesystem types of some entries by 'lockfs'. Options are also modified to remember
the original fstype.

3. One time the aufs mountpoint is the new root filesystem, initscripts are executed:
fstab(5) is parsed by 'mount -a', and then mount(8) calls mount.lockfs with the proper
arguments when a 'lockfs' fstype is encountered.

4. mount.lockfs parses arguments and checks if the filesystem has been whitelisted in
bilibop.conf(5), or not. If it is the case, the filesystem is mounted normally and the
fstab entry is modified to reflect the actual mount call. If neither the filesystem nor
the mountpoint have been whitelisted, then the filesystem is mounted elsewhere and
readonly, a temporary filesystem is mounted with proper options, size, permissions and
ownership, and an aufs is mounted on the MOUNTPOINT given as argument with the
lower/readonly and upper/writable branches previously set. The fstab entry is replaced
by three lines reflecting the actual mount calls. If something fails, mount.lockfs acts
as if the filesystem was whitelisted. See /usr/share/doc/bilibop-lockfs/README.Debian
for details.

OPTIONS

       lockfs_mount_helper  uses options and arguments as they are given by mount(8) after it has
       parsed the corresponding fstab(5) entry. So, options and arguments are mandatory and  come
       in the following order:

       FILESYSTEM
              Corresponding  to  the  first  field  in  fstab.  This must be a block device, or a
              symlink to a block device. If this field is given with one of the UUID=* or LABEL=*
              formats,  then  the  mount  command  translates it to the corresponding device name
              before to call the helper program.

       MOUNTPOINT
              Corresponding to the second field in fstab.

       -o MOUNTOPTIONS
              Corresponding to the fourth field in fstab. The mount options  are  parsed  by  the
              helper  script: if fstype=* is encountered, it is removed from the options and used
              to mount the readonly branch with this filesystem type. If ro,  noexec,  nosuid  or
              nodev  options  are encountered, they are added to the list of mount options of the
              writable branch.

FILES

       /etc/fstab
       /lib/bilibop/lockfs_mount_helper
       /usr/share/doc/bilibop-lockfs/README.Debian

AUTHOR