iankelling.org Git - distro-setup/blob - mount-latest-subvol

   1 #!/bin/bash
   2 # Copyright (C) 2016 Ian Kelling
   3 #
   4 # Licensed under the Apache License, Version 2.0 (the "License");
   5 # you may not use this file except in compliance with the License.
   6 # You may obtain a copy of the License at
   7 #
   8 #     http://www.apache.org/licenses/LICENSE-2.0
   9 #
  10 # Unless required by applicable law or agreed to in writing, software
  11 # distributed under the License is distributed on an "AS IS" BASIS,
  12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 # See the License for the specific language governing permissions and
  14 # limitations under the License.
  15
  16 # usage: mount-latest-subvol
  17
  18 [[ $EUID == 0 ]] || exec sudo -E "$BASH_SOURCE" "$@"
  19
  20 errcatch() {
  21     set -E; shopt -s extdebug
  22     _err-trap() {
  23         err=$?
  24         exec >&2
  25         set +x
  26         echo "${BASH_SOURCE[1]}:${BASH_LINENO[0]}:in \`$BASH_COMMAND' returned $err"
  27         bash-trace 2
  28         echo "$0: exiting with code $err"
  29         exit $err
  30     }
  31     trap _err-trap ERR
  32     set -o pipefail
  33 }
  34 bash-trace() {
  35     local -i argc_index=0 arg frame i start=${1:-1} max_indent=8 indent
  36     local source
  37     local extdebug=false
  38     if [[ $(shopt -p extdebug) == *-s* ]]; then
  39         extdebug=true
  40     fi
  41
  42     for ((frame=0; frame < ${#FUNCNAME[@]}-1; frame++)); do
  43         argc=${BASH_ARGC[frame]}
  44         argc_index+=$argc
  45         ((frame < start)) && continue
  46         if (( ${#BASH_SOURCE[@]} > 1 )); then
  47             source="${BASH_SOURCE[frame+1]}:${BASH_LINENO[frame]}:"
  48         fi
  49         indent=$((frame-start+1))
  50         indent=$((indent < max_indent ? indent : max_indent))
  51         printf "%${indent}s↳%sin \`%s" '' "$source" "${FUNCNAME[frame]}"
  52         if $extdebug; then
  53             for ((i=argc_index-1; i >= argc_index-argc; i--)); do
  54                 printf " %s" "${BASH_ARGV[i]}"
  55             done
  56         fi
  57         echo \'
  58     done
  59 }
  60 errcatch
  61
  62 tu() {
  63     while read -r line; do
  64         file="$1"
  65         grep -xFq "$line" "$file" || tee -a "$file"<<<"$line"
  66     done
  67 }
  68 e() { printf "%s\n" "$*"; "$@"; }
  69 mnt() {
  70     dir=$1
  71     if ! mountpoint $dir &>/dev/null; then
  72         mkdir -p $dir
  73         e mount $dir
  74     fi
  75 }
  76
  77 ret=0
  78
  79 ##### begin setup fstab for subvols we care about ######
  80 first_root_crypt=$(awk '$2 == "/" {print $1}' /etc/mtab)
  81 tu /etc/fstab <<EOF
  82 $first_root_crypt  /a  btrfs  noatime,subvol=a  0 0
  83 EOF
  84 case $HOSTNAME in
  85     treetowl|x2|frodo)
  86         tu /etc/fstab <<EOF
  87 $first_root_crypt  /q  btrfs  noatime,subvol=q  0 0
  88 $first_root_crypt  /m  btrfs  noatime,subvol=m  0 0
  89 /q/p  /p  none  bind  0 0
  90 EOF
  91         ;;
  92 esac
  93 ##### end setup fstab for subvols we care about ######
  94
  95 for vol in q a m; do
  96     d=/$vol
  97     if ! awk '{print $2}' /etc/fstab | grep -xF $d &>/dev/null; then
  98         continue
  99     fi
 100
 101
 102     ##### begin building up list of bind mounts  ######
 103     binds=() # list of bind mounts
 104     roots=($d) # list of bind mounts, plus the original mount
 105     while true; do
 106         new_roots=()
 107         for r in ${roots[@]}; do
 108             # eg. when r=/q/p, for lines like
 109             # /q/p  /p  none  bind  0 0
 110             # output /p
 111             new_roots+=($(sed -rn "s#^$r/\S+\s+(\S+)\s+none\s+bind\s.*#\1#p" /etc/fstab))
 112         done
 113         (( ${#new_roots} )) || break
 114         binds+=(${new_roots[@]})
 115         roots=( ${new_roots[@]} )
 116     done
 117     ##### end building up list of bind mounts  ######
 118
 119
 120     # if latest is already mounted, make sure binds are mounted and move on
 121     if e check-subvol-stale $d; then
 122         for b in ${binds[@]}; do
 123             mnt $b
 124         done
 125         continue
 126     fi
 127
 128     last_snap=$(</nocow/btrfs-stale/$vol)
 129     if [[ ! $last_snap ]]; then
 130         echo "$0: error. empty last_snap var"
 131         ret=1
 132         continue
 133     fi
 134
 135     umount_ret=true
 136     unmounted=()
 137     for dir in $(echo $d ${binds[*]}\ |tac -s\ ); do
 138         if mountpoint $dir; then
 139             if e umount -R $dir; then
 140                 unmounted+=($dir)
 141             else
 142                 umount_ret=false
 143                 ret=1
 144                 echo "$0: failed to umount $dir"
 145                 break
 146             fi
 147         fi
 148     done
 149
 150     if ! $umount_ret; then
 151         for dir in ${unmounted[@]}; do
 152             mnt $dir
 153         done
 154         continue
 155     fi
 156
 157     cd /mnt/root
 158     if [[ -e $vol ]]; then
 159         e btrfs sub del $vol
 160     fi
 161     # Note, we make a few assumptions in this script, like
 162     # $d was not a different subvol id than $vol, and
 163     # things otherwise didn't get mounted very strangely.
 164     e btrfs sub snapshot btrbk/$last_snap $vol
 165     for dir in $d ${binds[@]}; do
 166         e mnt $dir
 167     done
 168     stale_dir=/nocow/btrfs-stale
 169     rm -f $stale_dir/$d
 170 done
 171
 172 if [[ $HOSTNAME == treetowl ]]; then
 173     # partitioned it with fai partitioner outside of fai,
 174     # because it\'s worth it to have 1% space reserved for boot and
 175     # swap partitions in case I ever want to boot off those drives.
 176     # as root:
 177     # . /a/bin/fai/fai-wrapper
 178     # eval-fai-classfile /a/bin/fai/fai/config/class/51-multi-boot
 179     # fai-setclass ROTATIONAL
 180     # export LUKS_DIR=/q/root/luks/
 181     # # because the partition nums existed already
 182     # fai-setclass REPARTITION
 183     # /a/bin/fai/fai/config/hooks/partition.DEFAULT
 184
 185     devs=(
 186         ata-TOSHIBA_MD04ACA500_84REK6NTFS9A-part1
 187         ata-TOSHIBA_MD04ACA500_84R2K773FS9A-part1
 188         ata-TOSHIBA_MD04ACA500_8471K430FS9A-part1
 189         ata-TOSHIBA_MD04ACA500_8481K493FS9A-part1
 190     )
 191     first=true
 192     for dev in ${devs[@]}; do
 193         if $first; then
 194             first=false
 195             tu /etc/fstab <<EOF
 196 /dev/mapper/crypt_dev_$dev /i btrfs  noatime,subvol=i,noauto  0 0
 197 /dev/mapper/crypt_dev_$dev /mnt/iroot btrfs  noatime,subvolid=0,noauto  0 0
 198 EOF
 199         fi
 200         tu /etc/crypttab <<EOF
 201 crypt_dev_$dev  /dev/disk/by-id/$dev  /q/root/luks/host-treetowl  discard,luks
 202 EOF
 203         if [[ ! -e /dev/mapper/crypt_dev_$dev ]]; then
 204             cryptdisks_start crypt_dev_$dev
 205         fi
 206     done
 207     # note, could do an else here and have some kind of mount for /i
 208     # on other hosts.
 209 fi
 210
 211 exit $ret