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 # ssh and probably some other things care about parent directory
 121 # ownership, and ssh doesn\'t allow any group writable parent
 122 # directories, so we are forced to use a directory structure similar
 123 # to home directories
 124 f=(/mnt/root/btrbk/q.*)
 125 if [[ -e $f ]]; then
 126     fstab <<EOF
 127 $first_root_crypt  /q  btrfs  noatime,subvol=q,gid=1000  0 0
 128 /q/p  /p  none  bind  0 0
 129 EOF
 130 fi
 131
 132 f=(/mnt/root/btrbk/o.*)
 133 if [[ -e $f ]]; then
 134     fstab <<EOF
 135 $first_root_crypt  /o  btrfs  noatime,subvol=o  0 0
 136 /o/m  /m  none  bind  0 0
 137 EOF
 138 fi
 139
 140 if [[ $HOSTNAME == frodo ]]; then
 141     fstab <<EOF
 142 $first_root_crypt  /i  btrfs  noatime,subvol=i  0 0
 143 EOF
 144 fi
 145 ##### end setup fstab for subvols we care about ######
 146
 147 for vol in q a o i; do
 148     d=/$vol
 149     if ! awk '{print $2}' /etc/fstab | grep -xF $d &>/dev/null; then
 150         continue
 151     fi
 152
 153
 154     ##### begin building up list of bind mounts  ######
 155     binds=() # list of bind mounts
 156     roots=($d) # list of bind mounts, plus the original mount
 157     while true; do
 158         new_roots=()
 159         for r in ${roots[@]}; do
 160             # eg. when r=/q/p, for lines like
 161             # /q/p  /p  none  bind  0 0
 162             # output /p
 163             new_roots+=($(sed -rn "s#^$r/\S+\s+(\S+)\s+none\s+bind\s.*#\1#p" /etc/fstab))
 164         done
 165         (( ${#new_roots} )) || break
 166         binds+=(${new_roots[@]})
 167         roots=( ${new_roots[@]} )
 168     done
 169     ##### end building up list of bind mounts  ######
 170
 171
 172     # if latest is already mounted, make sure binds are mounted and move on
 173     if e check-subvol-stale $d; then
 174         mnt $d
 175         for b in ${binds[@]}; do
 176             mnt $b
 177         done
 178         continue
 179     fi
 180
 181     fresh_snap=$(</nocow/btrfs-stale/$vol)
 182     if [[ ! $fresh_snap ]]; then
 183         echo "$0: error. empty fresh_snap var"
 184         ret=1
 185         continue
 186     fi
 187
 188     umount_ret=true
 189     unmounted=()
 190     for dir in $(echo $d ${binds[*]}\ |tac -s\ ); do
 191         if mountpoint $dir; then
 192             if e umount -R $dir; then
 193                 unmounted+=($dir)
 194             else
 195                 kill-dir || kill-dir INT || kill-dir HUP || ! $force || kill-dir KILL ||:
 196
 197                 if e umount -R $dir; then
 198                     unmounted+=($dir)
 199                 else
 200                     echo "$0: failed to umount $dir"
 201                     umount_ret=false
 202                     ret=1
 203                     continue
 204                 fi
 205             fi
 206         fi
 207     done
 208
 209     if ! $umount_ret; then
 210         for dir in ${unmounted[@]}; do
 211             mnt $dir
 212         done
 213         continue
 214     fi
 215
 216     # todo: decipher /mnt/root, like we do in check-subvol-stale
 217     cd /mnt/root
 218     if [[ -e $vol ]]; then
 219         e mv $vol $vol.leaf.$(date +%Y%m%dT%H%M%S%z)
 220     fi
 221     # Note, we make a few assumptions in this script, like
 222     # $d was not a different subvol id than $vol, and
 223     # things otherwise didn't get mounted very strangely.
 224     e btrfs sub snapshot $fresh_snap $vol
 225     for dir in $d ${binds[@]}; do
 226         e mnt $dir
 227     done
 228     stale_dir=/nocow/btrfs-stale
 229     rm -f $stale_dir/$d
 230 done
 231
 232 ### disabled
 233 if [[ $HOSTNAME == treetowlxxxxxxxxx ]]; then
 234     # partitioned it with fai partitioner outside of fai,
 235     # because it\'s worth it to have 1% space reserved for boot and
 236     # swap partitions in case I ever want to boot off those drives.
 237     # as root:
 238     # . /a/bin/fai/fai-wrapper
 239     # eval-fai-classfile /a/bin/fai/fai/config/class/51-multi-boot
 240     # fai-setclass ROTATIONAL
 241     # export LUKS_DIR=/q/root/luks/
 242     # # because the partition nums existed already
 243     # fai-setclass REPARTITION
 244     # /a/bin/fai/fai/config/hooks/partition.DEFAULT
 245
 246     devs=(
 247         ata-TOSHIBA_MD04ACA500_84REK6NTFS9A-part1
 248         ata-TOSHIBA_MD04ACA500_84R2K773FS9A-part1
 249         ata-TOSHIBA_MD04ACA500_8471K430FS9A-part1
 250         ata-TOSHIBA_MD04ACA500_8481K493FS9A-part1
 251     )
 252     first=true
 253     for dev in ${devs[@]}; do
 254         if $first; then
 255             first=false
 256             tu /etc/fstab <<EOF
 257 /dev/mapper/crypt_dev_$dev /i btrfs  noatime,subvol=i,noauto  0 0
 258 /dev/mapper/crypt_dev_$dev /mnt/iroot btrfs  noatime,subvolid=0,noauto  0 0
 259 EOF
 260         fi
 261         tu /etc/crypttab <<EOF
 262 crypt_dev_$dev  /dev/disk/by-id/$dev  /q/root/luks/host-treetowl  discard,luks
 263 EOF
 264         if [[ ! -e /dev/mapper/crypt_dev_$dev ]]; then
 265             cryptdisks_start crypt_dev_$dev
 266         fi
 267     done
 268     # note, could do an else here and have some kind of mount for /i
 269     # on other hosts.
 270 fi
 271
 272 exit $ret