echo "$0: error: expected mountpoint argument"
fi
+stale-file() {
+ stale_dir=/nocow/btrfs-stale
+ stale_file=$stale_dir/$vol
+ if $stale; then
+ mkdir -p $stale_dir
+ printf "%s\n" $freshest_snap > $stale_file
+ ret=1
+ else
+ rm -f $stale_file
+ fi
+
+}
+
ret=0
for d; do
vol=${d##*/}
- cd /mnt/root/btrbk
- snaps=($vol.20*) # Assumes we are in the 21st century.
+ dev=$(sed -rn "s,^\s*([^#]\S*)\s+$d\s.*,\1,p" /etc/fstab|head -n1)
+ subvol_dir=$(sed -rn "s,^\s*[^#]\S*\s+$d\s.*\bsubvol=([a-zA-A/]+).*,\1,p" /etc/fstab|head -n1)
+ # 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 fi show $dev| sed -rn 's#.*path (/\S+)$#\1#p'); do
+ root_dir=$(sed -rn "s,^\s*$devx\s+(\S+).*\bsubvolid=0\b.*,\1,p" /etc/fstab|head -n1)
+ if [[ $root_dir ]]; then break; fi
+ done
+ svp=$root_dir/$subvol_dir # subvolume path
+
+ snaps=($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. this is expected for a brand new volume"
continue
fi
+
+ # get info on last received sub
+ last_received_gen=0
+ for f in ${snaps[@]}; do
+ show="$(btrfs sub show $f)"
+ if echo "$show" | grep -E "Received UUID:\s+[[:alnum:]]" &>/dev/null; then
+ cgen=$(echo "$show" | sed -rn 's,^\s*Gen at creation:\s+([0-9]+).*,\1,p')
+ if [[ $cgen -gt $last_received_gen ]]; then
+ last_received_cgen=$cgen
+ last_received=$f
+ fi
+ fi
+ done
+
+ # Get last_snap by date.
# when a btrbk bugfix makes it into the distro,
# we might replace this with btrbk list latest /mnt/root/$vol | ...
- # 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
+ 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 $d among ${snaps[@]}"
+ echo "$0: error: could not find latest snapshot for $svp among ${snaps[*]}"
ret=1
continue
fi
+
+ 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
+ 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')
+ if [[ $svp_cgen -ge $last_received_cgen ]]; then
+ stale=false
+ else
+ echo "$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-file
+ continue
+ fi
+
+ # fallback to using last_snap as the freshest
+ freshest_snap=$last_snap
stale=true
- # check that $d has $last_snap as a snapshot,
- # or else $d is a snapshot of $last_snap. In the second
- # case, we use a uuid comparison, which if I remember from the
- # docs, is a bit more robust, perhaps to renames.
- if btrfs sub show $d 2>/dev/null | sed '0,/^\s*Snapshot(s):/d;s/^\s*//' | \
+ # fresh if $svp has $last_snap as a snapshot,
+ if btrfs sub show $svp 2>/dev/null | sed '0,/^\s*Snapshot(s):/d;s/^\s*//' | \
grep -xF btrbk/$last_snap &>/dev/null; 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
+ 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$" &>/dev/null; then
stale=false
fi
fi
- stale_dir=/nocow/btrfs-stale
- stale_file=$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
- fi
+
+ stale-file
+
done
exit $ret
iankelling.org / git / distro-setup / blobdiff