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 $err
  30     }
  31     trap _err-trap ERR
  32     set -o pipefail
  33 }
  34 bash-trace() {
  35     local -i argc_index=0 frame i start=${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 $dir
  74     fi
  75 }
  76 fstab() {
  77     while read -r start mpoint end; do
  78         l="$start $mpoint $end"
  79         # kill off any lines that duplicate the mount point.
  80         sed --follow-symlinks -ri "\%$l%b;\%^\s*\S+\s+$mpoint\s%d" /etc/fstab
  81         tu /etc/fstab <<<"$l"
  82     done
  83 }
  84
  85 ret=0
  86
  87 ##### begin setup fstab for subvols we care about ######
  88 first_root_crypt=$(awk '$2 == "/" {print $1}' /etc/mtab)
  89 fstab <<EOF
  90 $first_root_crypt  /a  btrfs  noatime,subvol=a  0 0
  91 EOF
  92
  93 shopt -s nullglob
  94
  95 f=(/mnt/root/btrbk/q.*)
  96 if [[ -e $f ]]; then
  97     fstab <<EOF
  98 $first_root_crypt  /q  btrfs  noatime,subvol=q  0 0
  99 /q/p  /p  none  bind  0 0
 100 EOF
 101 fi
 102
 103 f=(/mnt/root/btrbk/o.*)
 104 if [[ -e $f ]]; then
 105     fstab <<EOF
 106 $first_root_crypt  /o  btrfs  noatime,subvol=o  0 0
 107 /o/m  /m  none  bind  0 0
 108 EOF
 109 fi
 110
 111 if [[ $HOSTNAME == frodo ]]; then
 112     fstab <<EOF
 113 $first_root_crypt  /i  btrfs  noatime,subvol=i  0 0
 114 EOF
 115 fi
 116 ##### end setup fstab for subvols we care about ######
 117
 118 for vol in q a o i; do
 119     d=/$vol
 120     if ! awk '{print $2}' /etc/fstab | grep -xF $d &>/dev/null; then
 121         continue
 122     fi
 123
 124
 125     ##### begin building up list of bind mounts  ######
 126     binds=() # list of bind mounts
 127     roots=($d) # list of bind mounts, plus the original mount
 128     while true; do
 129         new_roots=()
 130         for r in ${roots[@]}; do
 131             # eg. when r=/q/p, for lines like
 132             # /q/p  /p  none  bind  0 0
 133             # output /p
 134             new_roots+=($(sed -rn "s#^$r/\S+\s+(\S+)\s+none\s+bind\s.*#\1#p" /etc/fstab))
 135         done
 136         (( ${#new_roots} )) || break
 137         binds+=(${new_roots[@]})
 138         roots=( ${new_roots[@]} )
 139     done
 140     ##### end building up list of bind mounts  ######
 141
 142
 143     # if latest is already mounted, make sure binds are mounted and move on
 144     if e check-subvol-stale $d; then
 145         mnt $d
 146         for b in ${binds[@]}; do
 147             mnt $b
 148         done
 149         continue
 150     fi
 151
 152     fresh_snap=$(</nocow/btrfs-stale/$vol)
 153     if [[ ! $fresh_snap ]]; then
 154         echo "$0: error. empty fresh_snap var"
 155         ret=1
 156         continue
 157     fi
 158
 159     umount_ret=true
 160     unmounted=()
 161     for dir in $(echo $d ${binds[*]}\ |tac -s\ ); do
 162         if mountpoint $dir; then
 163             if e umount -R $dir; then
 164                 unmounted+=($dir)
 165             else
 166                 echo "$0: failed to umount $dir"
 167                 # lsof will fail if it finds no pids
 168                 if ! e timeout 4 lsof $dir; then
 169                     umount_ret=false
 170                     ret=1
 171                     continue
 172                 fi
 173                 pids=$(lsof -t $dir) ||:
 174                 kill $pids
 175                 sleep .5
 176                 if e umount -R $dir; then
 177                     unmounted+=($dir)
 178                 else
 179                     umount_ret=false
 180                     ret=1
 181                     continue
 182                 fi
 183             fi
 184         fi
 185     done
 186
 187     if ! $umount_ret; then
 188         for dir in ${unmounted[@]}; do
 189             mnt $dir
 190         done
 191         continue
 192     fi
 193
 194     # todo: decipher /mnt/root, like we do in check-subvol-stale
 195     cd /mnt/root
 196     if [[ -e $vol ]]; then
 197         e mv $vol $vol.leaf.$(date +%Y%m%dT%H%M%S%z)
 198     fi
 199     # Note, we make a few assumptions in this script, like
 200     # $d was not a different subvol id than $vol, and
 201     # things otherwise didn't get mounted very strangely.
 202     e btrfs sub snapshot $fresh_snap $vol
 203     for dir in $d ${binds[@]}; do
 204         e mnt $dir
 205     done
 206     stale_dir=/nocow/btrfs-stale
 207     rm -f $stale_dir/$d
 208 done
 209
 210 ### disabled
 211 if [[ $HOSTNAME == treetowlxxxxxxxxx ]]; then
 212     # partitioned it with fai partitioner outside of fai,
 213     # because it\'s worth it to have 1% space reserved for boot and
 214     # swap partitions in case I ever want to boot off those drives.
 215     # as root:
 216     # . /a/bin/fai/fai-wrapper
 217     # eval-fai-classfile /a/bin/fai/fai/config/class/51-multi-boot
 218     # fai-setclass ROTATIONAL
 219     # export LUKS_DIR=/q/root/luks/
 220     # # because the partition nums existed already
 221     # fai-setclass REPARTITION
 222     # /a/bin/fai/fai/config/hooks/partition.DEFAULT
 223
 224     devs=(
 225         ata-TOSHIBA_MD04ACA500_84REK6NTFS9A-part1
 226         ata-TOSHIBA_MD04ACA500_84R2K773FS9A-part1
 227         ata-TOSHIBA_MD04ACA500_8471K430FS9A-part1
 228         ata-TOSHIBA_MD04ACA500_8481K493FS9A-part1
 229     )
 230     first=true
 231     for dev in ${devs[@]}; do
 232         if $first; then
 233             first=false
 234             tu /etc/fstab <<EOF
 235 /dev/mapper/crypt_dev_$dev /i btrfs  noatime,subvol=i,noauto  0 0
 236 /dev/mapper/crypt_dev_$dev /mnt/iroot btrfs  noatime,subvolid=0,noauto  0 0
 237 EOF
 238         fi
 239         tu /etc/crypttab <<EOF
 240 crypt_dev_$dev  /dev/disk/by-id/$dev  /q/root/luks/host-treetowl  discard,luks
 241 EOF
 242         if [[ ! -e /dev/mapper/crypt_dev_$dev ]]; then
 243             cryptdisks_start crypt_dev_$dev
 244         fi
 245     done
 246     # note, could do an else here and have some kind of mount for /i
 247     # on other hosts.
 248 fi
 249
 250 exit $ret