machined: run clone operation asynchronously in the background

Cloning an image can be slow, if the image is not on a btrfs subvolume, hence
let's make sure we do this asynchronously in a child process, so that machined
isn't blocked as long as we process the client request.

This adds a new, generic "Operation" object to machined, that is used to track
these kind of background processes.

This is inspired by the MachineOperation object that already exists to make
copy operations asynchronous. A later patch will rework the MachineOperation
logic to use the generic Operation instead.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/machine/machined.c b/src/machine/machined.c
index f2c1966a6b..f7ceb5e603 100644
--- a/src/machine/machined.c
+++ b/src/machine/machined.c
@@ -70,6 +70,11 @@ void manager_free(Manager *m) {
 
         assert(m);
 
+        while (m->operations)
+                operation_free(m->operations);
+
+        assert(m->n_operations == 0);
+
         while ((machine = hashmap_first(m->machines)))
                 machine_free(machine);
 
@@ -336,6 +341,9 @@ int manager_startup(Manager *m) {
 static bool check_idle(void *userdata) {
         Manager *m = userdata;
 
+        if (m->operations)
+                return false;
+
         manager_gc(m, true);
 
         return hashmap_isempty(m->machines);