Mini Shell

#!/usr/bin/sh

type getarg > /dev/null 2>&1 || . /lib/dracut-lib.sh

btrfs_check_complete() {
    local _rootinfo _dev
    _dev="${1:-/dev/root}"
    [ -e "$_dev" ] || return 0
    _rootinfo=$(udevadm info --query=env "--name=$_dev" 2> /dev/null)
    if strstr "$_rootinfo" "ID_FS_TYPE=btrfs"; then
        info "Checking, if btrfs device complete"
        unset __btrfs_mount
        mount -o ro "$_dev" /tmp > /dev/null 2>&1
        __btrfs_mount=$?
        [ $__btrfs_mount -eq 0 ] && umount "$_dev" > /dev/null 2>&1
        return $__btrfs_mount
    fi
    return 0
}

btrfs_check_complete "$1"