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, 4 insertions, 0 deletions

diff --git a/src/machine/machined.h b/src/machine/machined.h
index e7d7dfdceb..7b9b148044 100644
--- a/src/machine/machined.h
+++ b/src/machine/machined.h
@@ -32,6 +32,7 @@ typedef struct Manager Manager;
 #include "image-dbus.h"
 #include "machine-dbus.h"
 #include "machine.h"
+#include "operation.h"
 
 struct Manager {
         sd_event *event;
@@ -49,6 +50,9 @@ struct Manager {
         LIST_HEAD(Machine, machine_gc_queue);
 
         Machine *host_machine;
+
+        LIST_HEAD(Operation, operations);
+        unsigned n_operations;
 };
 
 Manager *manager_new(void);