36d0c5b9d1
- init.sh: creates the @ / @home / @log / @snapshots subvolume layout on a target device (the installer step). - snapshot.sh: scheduled read-only snapshots with pruning, installed as /usr/local/sbin/arcline-snapshot. - rollback.sh: safe boot-to-snapshot rollback that refuses to touch the live @ and promotes a snapshot atomically.
90 lines
2.9 KiB
Bash
Executable File
90 lines
2.9 KiB
Bash
Executable File
#!/usr/bin/env bash
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# ─────────────────────────────────────────────────────────────────────────────
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# arcline-snapshot — btrfs snapshot manager (ships at /usr/local/sbin)
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#
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# arcline-snapshot snapshot take a snapshot of @ and @home
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# arcline-snapshot list list stored snapshots
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# arcline-snapshot prune [--keep N] keep N newest, delete the rest
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#
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# Snapshots are read-only copies under /.snapshots, so they survive a failed
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# upgrade. Run as root (or via sudo). Configured through the
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# arcline-snapshot.timer unit (see overlays/base/usr/lib/systemd/system/).
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# ─────────────────────────────────────────────────────────────────────────────
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set -euo pipefail
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ACTION="${1:-list}"
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SNAP_ROOT="/.snapshots"
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KEEP="${ARCLINE_SNAPSHOT_KEEP:-5}"
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TOP="/run/arcline-btrfs"
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require_root() {
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if [[ $EUID -ne 0 ]] && command -v sudo >/dev/null; then
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exec sudo -E "$0" "$@"
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elif [[ $EUID -ne 0 ]]; then
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echo "error: needs root" >&2; exit 1
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fi
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}
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ROOT_FS_TYPE="$(findmnt -no FSTYPE / 2>/dev/null || true)"
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if [[ "$ROOT_FS_TYPE" != "btrfs" ]]; then
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echo "info: root filesystem is '$ROOT_FS_TYPE', not btrfs — snapshots disabled"
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exit 0
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fi
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ROOT_DEV="$(findmnt -no SOURCE / | head -1)"
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mount_top() {
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mkdir -p "$TOP"
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mount -o subvolid=5,ro "$ROOT_DEV" "$TOP"
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trap 'umount "$TOP" 2>/dev/null || true; rmdir "$TOP" 2>/dev/null || true' EXIT
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}
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stamp() { date +%Y%m%dT%H%M%S; }
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case "$ACTION" in
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snapshot)
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require_root "$0" "$@"
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mount_top
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ts="$(stamp)"
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for sub in "@" "@home"; do
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[[ -d "$TOP/$sub" ]] || { echo "warn: subvolume $sub not found, skipping"; continue; }
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dst="$TOP/@snapshots/$ts-$sub"
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echo "snapshotting $sub → $dst"
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btrfs subvolume snapshot -r "$TOP/$sub" "$dst" >/dev/null
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done
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echo "snapshot taken: $ts"
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;;
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list)
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require_root "$0" "$@"
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mount_top
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if ! compgen -G "$TOP/@snapshots/*-@*" >/dev/null; then
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echo "no snapshots yet"
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exit 0
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fi
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for snap in "$TOP"/@snapshots/*-@*; do
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[[ -d "$snap" ]] || continue
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echo "$(basename "$snap")"
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done | sort -r
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;;
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prune)
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require_root "$0" "$@"
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mount_top
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if [[ "${2:-}" == "--keep" ]]; then KEEP="${3:-$KEEP}"; fi
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mapfile -t snaps < <(for s in "$TOP"/@snapshots/*-@*; do [[ -d "$s" ]] && echo "$s"; done | sort -r)
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if [[ ${#snaps[@]} -le $KEEP ]]; then
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echo "nothing to prune (${#snaps[@]} ≤ keep $KEEP)"
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exit 0
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fi
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for old in "${snaps[@]:$KEEP}"; do
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echo "deleting $(basename "$old")"
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btrfs subvolume delete "$old" >/dev/null
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done
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;;
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*)
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echo "usage: arcline-snapshot {snapshot|list|prune [--keep N]}" >&2
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exit 1
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;;
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esac
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