source: client/shared/lib/os-probes/init/10filesystems @ 1d1e06d

#!/bin/sh
# Make sure filesystems are available.
set +e  # ignore errors from modprobe

FILESYSTEMS='ext2 ext3 ext4 xfs jfs msdos vfat ntfs minix hfs hfsplus qnx4 ufs btrfs'
# fuse is needed to make grub-mount work.
FILESYSTEMS="$FILESYSTEMS fuse"
# The Ubuntu kernel udebs put a number of filesystem modules in
# fs-{core,secondary}-modules. It's fairly cheap to check for these too.
FILESYSTEMS="$FILESYSTEMS fs-core fs-secondary"

if [ ! -e /var/lib/os-prober/modules ]; then
        # Check for anna-install to make it easier to use os-prober outside
        # d-i.
        if type anna-install >/dev/null 2>&1 && [ -d /lib/debian-installer ]; then
                for fs in $FILESYSTEMS; do
                        ANNA_QUIET=1 DEBIAN_FRONTEND=none \
                        log-output -t os-prober \
                                anna-install "$fs-modules" || true
                done
                depmod -a >/dev/null 2>&1 || true
        fi

        for fs in $FILESYSTEMS; do
                case "$fs" in
                        fs-*)
                                ;;
                        *)
                                modprobe "$fs" 2>/dev/null | logger -t os-prober
                                ;;
                esac
        done

        # We only want to keep this state inside d-i, so this is as good a
        # check as any.
        if type anna-install >/dev/null 2>&1 && [ -d /lib/debian-installer ]; then
                touch /var/lib/os-prober/modules
        fi
fi