functions to send btrfs diffs back to the parent (incomplete)

these hard-code paths on my local machine

the names of the generated files are also not useful

1 files changed, 37 insertions, 0 deletions

diff --git a/btrfs-receive-root.sh b/btrfs-receive-root.sh
new file mode 100644
index 0000000..178fd64
--- /dev/null
+++ b/btrfs-receive-root.sh
@@ -0,0 +1,37 @@
+#!/bin/sh
+
+layer_dir=/home/d/sami
+seed_file=debian-live-8.4.0-amd64-standard.btrfs
+layer_file=debian-live-8.4.0-amd64-standard.layer.$$.btrfs
+layer_size=1000
+mountpoint=layer_dest.$$
+
+disable_stdout() { exec 3>&1; exec >&2; }
+enable_stdout() { exec >&3; }
+
+with_stdout() { enable_stdout; "$@"; disable_stdout; }
+
+create_layer_filesystem()
+{
+    [ ! -e "$layer_file" ] || return
+    mkdir -p "$mountpoint"                                     &&
+    dd if=/dev/zero of="$layer_file" bs=1M count="$layer_size" &&
+    mount -o subvol=/,compress "$seed_file" "$mountpoint"      &&
+    layer_dev=$(losetup -f --show "$layer_file")               &&
+    btrfs device add "$layer_dev" "$mountpoint"                &&
+    mount -o rw,remount "$mountpoint"
+}
+
+finish()
+{
+    umount "$mountpoint" &&
+    btrfstune -S1 "$layer_file"
+}
+
+set -ex
+
+cd "$layer_dir"                         &&
+disable_stdout                          &&
+create_layer_filesystem                 &&
+with_stdout btrfs receive "$mountpoint" &&
+finish