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 kill-dir() {
  85     found_pids=false
  86     sig=${1:-TERM}
  87     if pids=$(timeout 4 lsof -t $dir); then
  88         found_pids=true
  89         timeout 4 lsof -w $dir
  90         kill -$sig $pids
  91     fi
  92     # fuser will find open sockets that lsof won't, for example from gpg-agent.
  93     # note: -v shows kernel processes, which then doesn't return true when we want
  94     if timeout 4 fuser -m $dir &>/dev/null; then
  95         found_pids=true
  96         fuser -$sig -mvk $dir
  97     fi
  98     if $found_pids; then
  99         sleep .5
 100         return 0
 101     fi
 102     return 1
 103 }
 104
 105 force=false
 106 if [[ $1 == -f ]]; then
 107     force=true
 108 fi
 109
 110 ret=0
 111
 112 ##### begin setup fstab for subvols we care about ######
 113 first_root_crypt=$(awk '$2 == "/" {print $1}' /etc/mtab)
 114 fstab <<EOF
 115 $first_root_crypt  /a  btrfs  noatime,subvol=a  0 0
 116 EOF
 117
 118 shopt -s nullglob
 119
 120 f=(/mnt/root/btrbk/q.*)
 121 if [[ -e $f ]]; then
 122     fstab <<EOF
 123 $first_root_crypt  /q  btrfs  noatime,subvol=q  0 0
 124 /q/p  /p  none  bind  0 0
 125 EOF
 126 fi
 127
 128 f=(/mnt/root/btrbk/o.*)
 129 if [[ -e $f ]]; then
 130     fstab <<EOF
 131 $first_root_crypt  /o  btrfs  noatime,subvol=o  0 0
 132 /o/m  /m  none  bind  0 0
 133 EOF
 134 fi
 135
 136 if [[ $HOSTNAME == frodo ]]; then
 137     fstab <<EOF
 138 $first_root_crypt  /i  btrfs  noatime,subvol=i  0 0
 139 EOF
 140 fi
 141 ##### end setup fstab for subvols we care about ######
 142
 143 for vol in q a o i; do
 144     d=/$vol
 145     if ! awk '{print $2}' /etc/fstab | grep -xF $d &>/dev/null; then
 146         continue
 147     fi
 148
 149
 150     ##### begin building up list of bind mounts  ######
 151     binds=() # list of bind mounts
 152     roots=($d) # list of bind mounts, plus the original mount
 153     while true; do
 154         new_roots=()
 155         for r in ${roots[@]}; do
 156             # eg. when r=/q/p, for lines like
 157             # /q/p  /p  none  bind  0 0
 158             # output /p
 159             new_roots+=($(sed -rn "s#^$r/\S+\s+(\S+)\s+none\s+bind\s.*#\1#p" /etc/fstab))
 160         done
 161         (( ${#new_roots} )) || break
 162         binds+=(${new_roots[@]})
 163         roots=( ${new_roots[@]} )
 164     done
 165     ##### end building up list of bind mounts  ######
 166
 167
 168     # if latest is already mounted, make sure binds are mounted and move on
 169     if e check-subvol-stale $d; then
 170         mnt $d
 171         for b in ${binds[@]}; do
 172             mnt $b
 173         done
 174         continue
 175     fi
 176
 177     fresh_snap=$(</nocow/btrfs-stale/$vol)
 178     if [[ ! $fresh_snap ]]; then
 179         echo "$0: error. empty fresh_snap var"
 180         ret=1
 181         continue
 182     fi
 183
 184     umount_ret=true
 185     unmounted=()
 186     for dir in $(echo $d ${binds[*]}\ |tac -s\ ); do
 187         if mountpoint $dir; then
 188             if e umount -R $dir; then
 189                 unmounted+=($dir)
 190             else
 191                 kill-dir || kill-dir INT || kill-dir HUP || ! $force || kill-dir KILL ||:
 192
 193                 if e umount -R $dir; then
 194                     unmounted+=($dir)
 195                 else
 196                     echo "$0: failed to umount $dir"
 197                     umount_ret=false
 198                     ret=1
 199                     continue
 200                 fi
 201             fi
 202         fi
 203     done
 204
 205     if ! $umount_ret; then
 206         for dir in ${unmounted[@]}; do
 207             mnt $dir
 208         done
 209         continue
 210     fi
 211
 212     # todo: decipher /mnt/root, like we do in check-subvol-stale
 213     cd /mnt/root
 214     if [[ -e $vol ]]; then
 215         e mv $vol $vol.leaf.$(date +%Y%m%dT%H%M%S%z)
 216     fi
 217     # Note, we make a few assumptions in this script, like
 218     # $d was not a different subvol id than $vol, and
 219     # things otherwise didn't get mounted very strangely.
 220     e btrfs sub snapshot $fresh_snap $vol
 221     for dir in $d ${binds[@]}; do
 222         e mnt $dir
 223     done
 224     stale_dir=/nocow/btrfs-stale
 225     rm -f $stale_dir/$d
 226 done
 227
 228 ### disabled
 229 if [[ $HOSTNAME == treetowlxxxxxxxxx ]]; then
 230     # partitioned it with fai partitioner outside of fai,
 231     # because it\'s worth it to have 1% space reserved for boot and
 232     # swap partitions in case I ever want to boot off those drives.
 233     # as root:
 234     # . /a/bin/fai/fai-wrapper
 235     # eval-fai-classfile /a/bin/fai/fai/config/class/51-multi-boot
 236     # fai-setclass ROTATIONAL
 237     # export LUKS_DIR=/q/root/luks/
 238     # # because the partition nums existed already
 239     # fai-setclass REPARTITION
 240     # /a/bin/fai/fai/config/hooks/partition.DEFAULT
 241
 242     devs=(
 243         ata-TOSHIBA_MD04ACA500_84REK6NTFS9A-part1
 244         ata-TOSHIBA_MD04ACA500_84R2K773FS9A-part1
 245         ata-TOSHIBA_MD04ACA500_8471K430FS9A-part1
 246         ata-TOSHIBA_MD04ACA500_8481K493FS9A-part1
 247     )
 248     first=true
 249     for dev in ${devs[@]}; do
 250         if $first; then
 251             first=false
 252             tu /etc/fstab <<EOF
 253 /dev/mapper/crypt_dev_$dev /i btrfs  noatime,subvol=i,noauto  0 0
 254 /dev/mapper/crypt_dev_$dev /mnt/iroot btrfs  noatime,subvolid=0,noauto  0 0
 255 EOF
 256         fi
 257         tu /etc/crypttab <<EOF
 258 crypt_dev_$dev  /dev/disk/by-id/$dev  /q/root/luks/host-treetowl  discard,luks
 259 EOF
 260         if [[ ! -e /dev/mapper/crypt_dev_$dev ]]; then
 261             cryptdisks_start crypt_dev_$dev
 262         fi
 263     done
 264     # note, could do an else here and have some kind of mount for /i
 265     # on other hosts.
 266 fi
 267
 268 exit $ret