btrfs-progs/btrfs-completion

# original by Alfredo Esteban <aedelatorre at xxxxxxxxx>
# (http://www.spinics.net/lists/linux-btrfs/msg15899.html)
# edited by Joseph Wang <joequant at gmail.com>
# (http://lists.alioth.debian.org/pipermail/bash-completion-devel/2013-June/004868.html)
# edited by John C F <john.ch.fr at gmail.com> on 2015-02-02

_btrfs_devs()
{
    local DEVS
    DEVS=''; while read dev; do DEVS+="$dev "; done < <(lsblk -pnro name)
	COMPREPLY+=( $( compgen -W "$DEVS" -- "$cur" ) )
}

_btrfs_mnts()
{
	local MNTS
	MNTS=''
	while read mnt; do MNTS+="$mnt "
	done < <(mount | awk '{print $3}')
	COMPREPLY+=( $( compgen -W "$MNTS" -- "$cur" ) )
}

_btrfs() 
{
	local cur prev words cword
    _init_completion || return

    COMPREPLY=()
    
	local cmd=${words[1]}

    commands='subvolume filesystem balance device scrub check rescue restore inspect-internal property send receive quota qgroup replace help version'
    commands_subvolume='create delete list snapshot find-new get-default set-default show sync'
    commands_filesystem='defragment sync resize show df label'
    commands_balance='start pause cancel resume status'
    commands_device='scan add delete ready stats'
    commands_scrub='start cancel resume status'
    commands_rescue='chunk-recover super-recover'
    commands_inspect_internal='inode-resolve logical-resolve subvolid-resolve rootid'
    commands_property='get set list'
    commands_quota='enable disable rescan'
    commands_qgroup='assign remove create destroy show limit'
    commands_replace='start status cancel'

	if [[ "$cur" == -* && $cword -le 3 && "$cmd" != "help" ]]; then
		COMPREPLY=( $( compgen -W '--help' -- "$cur" ) )
		return 0
	fi

    if [[ $cword -eq 1 ]]; then
        COMPREPLY=( $( compgen -W "$commands" -- "$cur" ) )
        return 0
    elif [[ $cword -eq 2 ]]; then
        case $cmd in
            subvolume)
                opts="$commands_subvolume"
                ;;
            filesystem)
                opts="$commands_filesystem"
                ;;
            balance)
                opts="$commands_balance"
                ;;
            device)
                opts="$commands_device"
                ;;
            scrub)
                opts="$commands_scrub"
                ;;
            check)
                _btrfs_devs
				return 0
                ;;
            rescue)
                opts="$commands_rescue"
                ;;
            restore)
                _btrfs_devs
				return 0
                ;;
            inspect-internal)
                opts="$commands_inspect_internal"
                ;;
            property)
                opts="$commands_property"
                ;;
            send|receive)
                _filedir -d
                return 0
                ;;
            quota)
                opts="$commands_quota"
                ;;
            qgroup)
                opts="$commands_qgroup"
                ;;
            replace)
                opts="$commands_replace"
                ;;
            help)
                opts="--full"
                ;;
            version)
                return 0
                ;;
        esac
        COMPREPLY=( $( compgen -W "$opts" -- "$cur" ) )
        return 0
    elif [[ $cword -eq 3 ]]; then
        case $cmd in
            filesystem)
				case $prev in
					defragment)
						_filedir
						return 0
						;;
					label)
						_btrfs_mnts
						_btrfs_devs
						return 0
						;;
				esac
                ;;
            device|rescue)
				_btrfs_devs
                return 0
                ;;
            replace)
                case $prev in
                    status|cancel)
						_btrfs_mnts
                        return 0
                        ;;
                    start)
						_btrfs_devs
                        return 0
                        ;;
                esac
                ;;
        esac
    fi

    if [[ "$cmd" == "receive" && "$prev" == "-f" ]]; then
        _filedir
        return 0
    fi

    _filedir -d
    return 0  
}

complete -F _btrfs btrfs