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