4 files changed, 87 insertions, 27 deletions

diff --git a/btrfs-functions.sh b/btrfs-functions.sh
index 3648c24..b83b94d 100644
--- a/btrfs-functions.sh
+++ b/btrfs-functions.sh
@@ -100,28 +100,52 @@ btrfs_show_default_path()
     mp=$(btrfs_get_mountpoint "$mp") || die # TODO: fix caller?
     btrfs_mountpoint "$mp" || die "not a mountpoint: $mp"
     path=$(btrfs subvolume get-default "$mp"/|sed -n -e 's/.* path //p')
-    printf '%s\n' "$mp/$path"
+    if [ "$path" ]; then
+        printf '%s\n' "$mp/$path"
+    else
+        printf '%s\n' "$mp"
+    fi
+}
+
+btrfs_show_default_id()
+{
+    $(ARGS_NE mp)
+    local id
+    mp=$(btrfs_get_mountpoint "$mp") || die # TODO: fix caller?
+    btrfs_mountpoint "$mp" || die "not a mountpoint: $mp"
+    id=$(btrfs subvolume get-default "$mp"/|sed -n -e 's/^ID \([^ ]*\) .*/\1/p')
+    [ "$id" ] || return
+    echo $id
 }
 
 btrfs_replace_default_subvolume_with()
 {
     $(ARGS_NE new_default)
-    local old_default subvol_id
-    old_default=$(btrfs_show_default_path "$new_default") || die
+    local old_default old_default_id new_default_id
+    old_default_id=$(btrfs_show_default_id "$new_default")       || die
+    new_default_id=$(btrfs_show_subvolume_id "$new_default")     || die
+
+    [ "$new_default_id" = "$old_default_id" ] && return
+
+    if [ "$old_default_id" != 5 ]; then
+        old_default=$(btrfs_show_default_path "$new_default")    || die
+    else
+        old_default=
+    fi
 
-    [ "$new_default" = "$old_default" ] && return
+    btrfs subvolume set-default "$new_default_id" "$new_default" || die
 
-    subvol_id=$(btrfs_show_subvolume_id "$new_default")       || die
-    btrfs subvolume set-default "$subvol_id" "$new_default" || die
-    btrfs subvolume delete "$old_default"
-    sex mv "$new_default" "$old_default"
+    if [ "$old_default" ]; then
+        btrfs subvolume delete "$old_default"
+        sex mv "$new_default" "$old_default"
+    fi
 }
 
 btrfs_show_subvolume_id()
 {
     $(ARGS_NE path)
     local result
-    result=$(btrfs subvolume show "$path" | sed -n -e 's/^[ \t]*Subvolume ID:[ \t]*//p')
+    result=$(btrfs subvolume show "$path" | sed -n -e 's/^[ \t]*Subvolume ID:[ \t]*//p; s/.*is toplevel subvolume/5/p')
     if [ "$result" ]
     then printf '%s\n' "$result"
     else false
diff --git a/btrfs-receive-root.sh b/btrfs-receive-root.sh
index 178fd64..175dd49 100644
--- a/btrfs-receive-root.sh
+++ b/btrfs-receive-root.sh
@@ -1,10 +1,7 @@
 #!/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.$$.btrfs
-layer_size=1000
-mountpoint=layer_dest.$$
+. sami/btrfs-functions.sh
+. sami/var.sh
 
 disable_stdout() { exec 3>&1; exec >&2; }
 enable_stdout() { exec >&3; }
@@ -14,24 +11,38 @@ 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" "$mountpoint"                &&
+    ! mountpoint "$mountpoint" || return
+    mkdir -p "$mountpoint"                                         &&
+    sex dd if=/dev/zero of="$layer_file" bs=1M count="$layer_size" &&
+    sex mount -o subvol=/,compress "$seed_file" "$mountpoint"      &&
+    layer_dev=$(losetup -f --show "$layer_file")                   &&
+    sex btrfs device add "$layer_dev" "$mountpoint"                &&
     mount -o rw,remount "$mountpoint"
 }
 
 finish()
 {
-    umount "$mountpoint" &&
-    btrfstune -S1 "$layer_file"
+    btrfs_replace_default_subvolume_with "$mountpoint"/"$receive_subv" &&
+    umount "$mountpoint"                                               &&
+    sex btrfstune -S1 "$layer_file"                                    &&
+    losetup -d "$layer_dev"
 }
 
-set -ex
+set -e
+disable_stdout
+
+receive_dest=$1
+receive_subv=$2
+
+[ "$receive_subv" ]
+[ "$receive_dest" ]
+
+mountpoint=$(realpath -m --relative-base=. "$receive_dest")
+
+seed_file=sami/debian-live-8.4.0-amd64-standard.btrfs
+layer_file=sami/debian-live-8.4.0-amd64-standard.layer.$receive_subv.btrfs
+layer_size=1000
 
-cd "$layer_dir"                         &&
-disable_stdout                          &&
-create_layer_filesystem                 &&
-with_stdout btrfs receive "$mountpoint" &&
+create_layer_filesystem
+with_stdout sex btrfs receive "$mountpoint"
 finish
diff --git a/btrfs-send-root.sh b/btrfs-send-root.sh
index 6152db8..25e60f2 100644
--- a/btrfs-send-root.sh
+++ b/btrfs-send-root.sh
@@ -10,7 +10,8 @@ rootfs_uuid ()
 remote_btrfs_receiver()
 {
 #   ssh "$BTRFS_RECEIVE_DESTINATION_HOST" -- "sudo btrfs receive $(shellescape "$BTRFS_RECEIVE_DESTINATION_PATH")"
-    ssh "$BTRFS_RECEIVE_DESTINATION_HOST" -- "sudo sh sami/btrfs-receive-root.sh"
+    ssh "$BTRFS_RECEIVE_DESTINATION_HOST" -- \
+        "sudo sh sami/btrfs-receive-root.sh $(shellescape "$BTRFS_RECEIVE_DESTINATION_PATH") $(shellescape "$BTRFS_RECEIVE_SUBVOLUME_NAME")"
 }
 
 dummy_receiver()
@@ -32,6 +33,7 @@ push_remote()
     esac
     local BTRFS_RECEIVE_DESTINATION_PATH="${ssh_dst#*:}"
     local BTRFS_RECEIVE_DESTINATION_HOST="${ssh_dst%%:*}"
+    local BTRFS_RECEIVE_SUBVOLUME_NAME="${snap_dir#$mnt/}"
     push_helper false "$snap_dir" "$prev_dir" "$src" remote_btrfs_receiver
 }
 
diff --git a/xorriso-layer.sh b/xorriso-layer.sh
new file mode 100755
index 0000000..1afb9f8
--- /dev/null
+++ b/xorriso-layer.sh
@@ -0,0 +1,23 @@
+#!/bin/bash
+
+outdev=debian-live-8.4.0-amd64-standard.btrfs.layered.iso
+indev=debian-live-8.4.0-amd64-standard.btrfs.iso
+volid=SamizdatLive
+btrfs_layer_iso_path=live/layer.btrfs
+btrfs_layer_filesystem=debian-live-8.4.0-amd64-standard.layer.snapshot.2016-04-22.154447.btrfs
+
+die() { printf '%s\n' "$*"; exit 1; }
+
+set -ex
+
+cp --reflink "$indev" "$outdev"~
+time xorriso \
+        -drive_class clear_list all \
+        -outdev "$outdev"~ -indev "$outdev"~ \
+        -report_about mishap \
+        -volid "$volid" \
+        -return_with sorry 0 \
+        -pathspecs on -overwrite on \
+        -add_plainly any \
+        "${btrfs_layer_iso_path}=${btrfs_layer_filesystem}"
+mv -f "$outdev"~ "$outdev"