do not use local head file

simply use a different head snapshot for each remote

if there aren't many remotes, it is a premature optimization

1 files changed, 8 insertions, 25 deletions

diff --git a/go.sh b/go.sh
index 65aa592..7487dfa 100755
--- a/go.sh
+++ b/go.sh
@@ -38,14 +38,6 @@ get_age()
         echo $((now - then))
 }
 
-remove_old_link()
-{
-        if [ -L "$1" ] && [ "$(get_age "$1")" -gt "$2" ]
-        then
-                rm -- "$1"
-        fi
-}
-
 set -e
 check_dependencies
 check_user_is_root
@@ -76,34 +68,25 @@ dst=${config[destination]}
 remote_head=${config[head]}
 
 is_subvolume "$src"
-local_head_link=${src%/}/.snapshot~HEAD
 
-remove_old_link "$local_head_link" "$MAX_AGE_SECONDS"
-
-if [ -e "$local_head_link" ]
+if [ "$(get_age "$remote_head")" -le "$MAX_AGE_SECONDS" ]
 then
-        local_head=$(realpath -e "$local_head_link")
+        echo "Up-to-date." >&2
+        exit
 else
         new_snapshot=${src%/}/.snapshot~$(date -Ins)
         btrfs subvolume snapshot -r -- "$src" "$new_snapshot"
-        # We don't need to create this link at all.
-        ln -rs -T "$new_snapshot" "$local_head_link"
-        local_head=$new_snapshot
 fi
 
-is_subvolume "$local_head"
+btrfs send ${remote_head:+ -p "$remote_head"} -- "$new_snapshot" | pv | btrfs receive -- "$dst"
+jq --arg h "$new_snapshot" '. | .head=$h' <"$config_file" >"$config_file_temp"
+mv -T -- "$config_file_temp" "$config_file"
 
-if [ "${local_head##*/}" = "${remote_head##*/}" ]
+if [ "$remote_head" ]
 then
-        echo "Up-to-date." >&2
-        exit
+        btrfs subvolume delete "$remote_head"
 fi
 
-btrfs send ${remote_head:+ -p "$remote_head"} -- "$local_head" | pv | btrfs receive -- "$dst"
-jq --arg h "$local_head" '. | .head=$h' <"$config_file" >"$config_file_temp"
-# TODO: btrfs subvolume delete "$remote_head" but first check for other config files!
-mv -T -- "$config_file_temp" "$config_file"
-
 ### OK, basic idea:
 #
 ## the system has a list of source subvolumes