experimental patch to keep vm running during snapshot creation

diff --git a/debian/patches/savevm-live.patch b/debian/patches/savevm-live.patch
new file mode 100644 (file)
index 0000000..c949910
--- /dev/null
+++ b/debian/patches/savevm-live.patch
@@ -0,0 +1,55 @@
+Index: new/savevm-async.c
+===================================================================
+--- new.orig/savevm-async.c    2012-09-24 07:59:38.000000000 +0200
++++ new/savevm-async.c 2012-09-24 08:03:38.000000000 +0200
+@@ -151,6 +151,8 @@
+ 
+ static void block_state_put_ready(void *opaque)
+ {
++    uint64_t remaining;
++    int64_t maxlen;
+     int ret;
+ 
+     if (snap_state.state != SAVE_STATE_ACTIVE) {
+@@ -158,16 +160,25 @@
+         return;
+     }
+ 
+-    if (!runstate_check(RUN_STATE_SAVE_VM)) {
+-        save_snapshot_error("put_ready returning because of wrong run state");
+-        return;
++    ret = qemu_savevm_state_iterate(snap_state.file);
++    remaining = ram_bytes_remaining();
++
++    // stop if we get to the end of available space,
++    // or if remaining is just a few MB
++    maxlen = bdrv_getlength(snap_state.bs) - 30*1024*1024;
++    if ((remaining < 100000) || ((snap_state.bs_pos + remaining) >= maxlen)) {
++        if (runstate_is_running()) {
++            vm_stop(RUN_STATE_SAVE_VM);
++        }
+     }
+ 
+-    ret = qemu_savevm_state_iterate(snap_state.file);
+     if (ret < 0) {
+         save_snapshot_error("qemu_savevm_state_iterate error %d", ret);
+         return;
+     } else if (ret == 1) {
++        if (runstate_is_running()) {
++            vm_stop(RUN_STATE_SAVE_VM);
++        }
+         DPRINTF("savevm inerate finished\n");
+         if ((ret = qemu_savevm_state_complete(snap_state.file)) < 0) {
+             save_snapshot_error("qemu_savevm_state_complete error %d", ret);
+@@ -211,10 +222,8 @@
+         snap_state.error = NULL;
+     }
+ 
+-    /* stop the VM */
+-    vm_stop(RUN_STATE_SAVE_VM);
+-
+     if (!has_statefile) {
++        vm_stop(RUN_STATE_SAVE_VM);
+         snap_state.state = SAVE_STATE_COMPLETED;
+         return;
+     }