#!/bin/bash
+# Copyright (C) 2016 Ian Kelling
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
-[[ $EUID == 0 ]] || exec sudo -E "$BASH_SOURCE" "$@"
+
+[[ $EUID == 0 ]] || exec sudo -E "${BASH_SOURCE[0]}" "$@"
set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR
shopt -s nullglob
-if [[ ! $@ ]]; then
- echo "$0: error: expected mountpoint argument"
+usage() {
+ cat <<EOF
+usage: $0 SUBVOL_MOUNTPOINT...
+
+In git this is not not executable because it's meant to be installed
+using ./install-my-scripts
+
+If latest subvols \$@ are not mounted, print a message, and print
+the unstale subvol name into /nocow/btrfs-stale/\$subvol
+
+Fresh is opposite of stale. To be fresh, either SUBVOL_MOUNTPOINT is a
+snapshot of the latest, or the latest snapshot is snapshot of
+SUBVOL_MOUNTPOINT.
+
+-d Enable debug output
+-h|--help Print help and exit.
+
+Note: Uses GNU getopt options parsing style
+EOF
+ exit $1
+}
+
+##### begin command line parsing ########
+
+debug=false # default
+temp=$(getopt -l help,d hd "$@") || usage 1
+eval set -- "$temp"
+while true; do
+ case $1 in
+ -d) debug=true; shift ;;
+ -h|--help) usage ;;
+ --) shift; break ;;
+ *) echo "$0: Internal error! unexpected args: $*" ; exit 1 ;;
+ esac
+done
+
+if [[ ! $1 ]]; then
+ echo "$0: error: expected mountpoint argument"
fi
-ret=0
+stale-file() {
+ stale_dir=/nocow/btrfs-stale
+ stale_file=$stale_dir/$vol
+ if $stale; then
+ mkdir -p $stale_dir
+ printf "%s\n" $freshest_snap > $stale_file
+ else
+ rm -f $stale_file
+ fi
+
+}
+d() {
+ if $debug; then
+ printf "%s\n" "$*"
+ fi
+}
+
for d; do
- vol=${d##*/}
- cd /mnt/root/btrbk
- snaps=($vol.20*)
- if [[ ! $snaps ]]; then
- # no snapshots yet
- continue
+ vol=${d##*/}
+ # second field, non-comment line == $d
+ dev=$(sed -rn "s,^\s*([^#]\S*)\s+$d\s.*,\1,p" /etc/fstab /etc/mtab|head -n1)
+
+ d dev=$dev
+ subvol_dir=$(sed -rn "s,^\s*[^#]\S*\s+$d\s.*\bsubvol=([a-zA-A/]+).*,\1,p" /etc/fstab /etc/mtab|head -n1)
+ d subvol_dir=$subvol_dir
+ # note, we need $dev because $d might not be mounted, and we do this loop
+ # because the device in fstab for the rootfs can be different.
+ for devx in $(btrfs fil show $dev| sed -rn 's#.*path (/\S+)$#\1#p'); do
+ d devx=$devx
+ root_dir=$(sed -rn "s,^\s*$devx\s+(\S+).*\bsubvolid=[05]\b.*,\1,p" /etc/mtab /etc/fstab|head -n1)
+ if [[ $root_dir ]]; then
+ d root_dir=$root_dir
+ break
fi
- # when a btrbk bugfix makes it into the distro,
- # we might replace this with btrbk list latest /mnt/root/$vol | ...
- # note: this is duplicated in mount-latest-subvol
- last_snap=$(
- for f in ${snaps[@]}; do
- printf "%s %s\n" $(date -d $(sed -r 's/(.{4})(..)(.{5})(..)(.*)/\1-\2-\3:\4:\5/' <<<${f#$vol.}) +%s) $f
- done | sort -r | head -n 1 | awk '{print $2}'
- )
- if [[ ! $last_snap ]]; then
- echo "$d stale"
- ret=1
- continue
+ done
+ if [[ ! $root_dir ]]; then
+ echo "$0: error could not find root subvol mount for $dev" >&2
+ exit 1
+ fi
+ svp=$root_dir/$subvol_dir
+ d "svp=$svp # subvolume path"
+
+ snaps=($root_dir/btrbk/$subvol_dir.20*) # Assumes we are in the 21st century.
+ if [[ ! ${snaps[*]} ]]; then
+ # no snapshots yet
+ echo "$0: warning: no snapshots found at $root_dir/btrbk/$subvol_dir.20*. this is expected for a brand new volume"
+ continue
+ fi
+
+ # get info on last received sub
+ last_received=
+ last_received_cgen=0
+ for f in ${snaps[@]}; do
+ show="$(btrfs sub show $f)"
+ if echo "$show" | grep -E "Received UUID:\s+[[:alnum:]]" &>/dev/null; then
+ d found received uuid in $f
+ cgen=$(echo "$show" | sed -rn 's,^\s*Gen at creation:\s+([0-9]+).*,\1,p')
+ if [[ $cgen -gt $last_received_cgen ]]; then
+ last_received_cgen=$cgen
+ last_received=$f
+ fi
fi
+ done
+ d last_received_cgen=$last_received_cgen
+ d last_received=$last_received
+
+ # Get last_snap by date.
+ # when a btrbk bugfix makes it into the distro,
+ # we might replace this with btrbk list latest /mnt/root/$vol | ...
+ last_snap=$(
+ for s in ${snaps[@]}; do
+ f=${s##*/}
+ unix_time=$(date -d $(sed -r 's/(.{4})(..)(.{5})(..)(.*)/\1-\2-\3:\4:\5/' <<<${f#$vol.}) +%s)
+ printf "%s %s\n" $unix_time $s
+ done | sort -r | head -n 1 | awk '{print $2}'
+ )
+ if [[ ! $last_snap ]]; then
+ # should not happen.
+ echo "$0: error: could not find latest snapshot for $svp among ${snaps[*]}" >&2
+ exit 1
+ fi
+ d last_snap=$last_snap
+
+ if [[ ! -e $svp ]]; then
+ echo "$0: warning: subvol does not exist: $svp"
+ echo "$0 assuming this host was just for receiving and latest snap is freshest"
+ freshest_snap=$last_snap
stale=true
- if btrfs sub show $d|sed '0,/^\t*Snapshot(s):/d;s/^\s*//' | \
- grep -xF btrbk/$last_snap &>/dev/null; then
- stale=false
+ stale-file
+ continue
+ fi
+
+
+ # if there is a last_received, we can assume stale or fresh if we are newer/older
+ if [[ $last_received ]]; then
+ svp_cgen=$(btrfs sub show $svp | sed -rn 's,^\s*Gen at creation:\s+([0-9]+).*,\1,p')
+ d svp_cgen=$svp_cgen
+ if [[ $svp_cgen -ge $last_received_cgen ]]; then
+ stale=false
else
- last_uuid=$(btrfs sub show $last_snap| awk '$1 == "UUID:" {print $2}')
- if btrfs sub show $d| grep "^\s*Parent UUID:\s*$last_uuid$" &>/dev/null; then
- stale=false
- fi
+ d "$svp stale: it's gen at creation, $svp_cgen, is earlier than the last received snapshot, $last_received's gen at creation: $last_received_cgen"
+ freshest_snap=$last_received
+ stale=true
fi
- stale_dir=/nocow/btrfs-stale
- stale_file=$stale_dir/$vol
- if $stale; then
- mkdir -p $stale_dir
- printf "%s\n" $last_snap > $stale_file
- echo "$d stale"
- ret=1
- continue
- else
- rm -f $stale_file
+ stale-file
+ continue
+ fi
+
+ # fallback to using last_snap as the freshest
+ freshest_snap=$last_snap
+ stale=true
+ # fresh if $svp has $last_snap as a snapshot,
+ if btrfs sub show $svp 2>/dev/null | sed '0,/^\s*Snapshot(s):/d;s/^\s*//' | \
+ grep -xF ${last_snap#$root_dir/} ; then
+ stale=false
+ else # or else $svp is a snapshot of $last_snap. we use a uuid
+ # comparison, which if I remember from the docs, is a bit more
+ # robust, perhaps to renames.
+ last_snap_uuid=$(btrfs sub show $last_snap| awk '$1 == "UUID:" {print $2}')
+ if btrfs sub show $svp| grep "^\s*Parent UUID:\s*$last_snap_uuid$" &>/dev/null; then
+ stale=false
fi
-done
-exit $ret
+ fi
+ stale-file
+done
iankelling.org / git / distro-setup / blobdiff