From f641a5445e74a3eb48da311dda9cf12118b39bf4 Mon Sep 17 00:00:00 2001
From: Alex Denes <caskd@redxen.eu>
Date: Sat, 9 Nov 2024 20:19:38 +0000
Subject: [PATCH] Allow override of dstdir with subvolume delta and add
 snapshot with retention

---
 btrfs/btrfs-subvolume-delta |  2 +-
 btrfs/snapshot              | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100755 btrfs/snapshot

diff --git a/btrfs/btrfs-subvolume-delta b/btrfs/btrfs-subvolume-delta
index 9b2b679..6d911bc 100755
--- a/btrfs/btrfs-subvolume-delta
+++ b/btrfs/btrfs-subvolume-delta
@@ -3,7 +3,7 @@ set -e
 
 SRC="$1"
 RECV="$2"
-DSTDIR="$SRC/.snap"
+DSTDIR="$SRC/${3:-.snap}"
 CDATE="$(date '+%s')"
 PREV="prev"
 CUR="cur"
diff --git a/btrfs/snapshot b/btrfs/snapshot
new file mode 100755
index 0000000..4a61e8e
--- /dev/null
+++ b/btrfs/snapshot
@@ -0,0 +1,18 @@
+#!/bin/sh
+#
+# BTRFS rolling snapshots
+# CC0 ~caskd
+
+: ${SRC:?'Source not defined'}
+: ${DEST:?'Destination not defined'}
+: ${NAME:?'Name not defined'}
+: ${SN:?'Selection name not defined'}
+: ${RT:?'Retention time not defined'}
+
+s="$SRC"
+d="$DEST/$SN/$NAME"
+
+mkdir -p "${d%/*}"
+find "$DEST" -mindepth 1 -maxdepth 1 -type d -ctime +"$RT" -exec echo "{}/$NAME" ';' | xargs btrfs subvolume del
+btrfs subvolume delete "$d"
+btrfs subvolume snapshot -r "$s" "$d"