pve-qemu-qoup/debian/patches/pve/0040-PVE-savevm-async-set-up-migration-state.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Stefan Reiter <s.reiter@proxmox.com>
Date: Wed, 8 Apr 2020 15:29:03 +0200
Subject: [PATCH] PVE: savevm-async: set up migration state

code mostly adapted from upstream savevm.c

Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
---
 savevm-async.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/savevm-async.c b/savevm-async.c
index 790e27ae37..a38b15d652 100644
--- a/savevm-async.c
+++ b/savevm-async.c
@@ -225,6 +225,7 @@ static void *process_savevm_thread(void *opaque)
 {
     int ret;
     int64_t maxlen;
+    MigrationState *ms = migrate_get_current();
 
     rcu_register_thread();
 
@@ -234,8 +235,7 @@ static void *process_savevm_thread(void *opaque)
 
     if (ret < 0) {
         save_snapshot_error("qemu_savevm_state_setup failed");
-        rcu_unregister_thread();
-        return NULL;
+        goto out;
     }
 
     while (snap_state.state == SAVE_STATE_ACTIVE) {
@@ -287,6 +287,12 @@ static void *process_savevm_thread(void *opaque)
     qemu_bh_schedule(snap_state.cleanup_bh);
     qemu_mutex_unlock_iothread();
 
+out:
+    /* set migration state accordingly and clear soon-to-be stale file */
+    migrate_set_state(&ms->state, MIGRATION_STATUS_SETUP,
+                      ret ? MIGRATION_STATUS_FAILED : MIGRATION_STATUS_COMPLETED);
+    ms->to_dst_file = NULL;
+
     rcu_unregister_thread();
     return NULL;
 }
@@ -294,6 +300,7 @@ static void *process_savevm_thread(void *opaque)
 void qmp_savevm_start(bool has_statefile, const char *statefile, Error **errp)
 {
     Error *local_err = NULL;
+    MigrationState *ms = migrate_get_current();
 
     int bdrv_oflags = BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH;
 
@@ -303,6 +310,17 @@ void qmp_savevm_start(bool has_statefile, const char *statefile, Error **errp)
         return;
     }
 
+    if (migration_is_running(ms->state)) {
+        error_set(errp, ERROR_CLASS_GENERIC_ERROR, QERR_MIGRATION_ACTIVE);
+        return;
+    }
+
+    if (migrate_use_block()) {
+        error_set(errp, ERROR_CLASS_GENERIC_ERROR,
+                  "Block migration and snapshots are incompatible");
+        return;
+    }
+
     /* initialize snapshot info */
     snap_state.saved_vm_running = runstate_is_running();
     snap_state.bs_pos = 0;
@@ -341,6 +359,14 @@ void qmp_savevm_start(bool has_statefile, const char *statefile, Error **errp)
         goto restart;
     }
 
+    /*
+     * qemu_savevm_* paths use migration code and expect a migration state.
+     * State is cleared in process_savevm_thread, but has to be initialized
+     * here (blocking main thread, from QMP) to avoid race conditions.
+     */
+    migrate_init(ms);
+    memset(&ram_counters, 0, sizeof(ram_counters));
+    ms->to_dst_file = snap_state.file;
 
     error_setg(&snap_state.blocker, "block device is in use by savevm");
     blk_op_block_all(snap_state.target, snap_state.blocker);