[Qemu-devel] [PATCH] migration: Recover block devices if failure in device state

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

In e91d895 I added the new pause-before-switchover mechanism
to allow migration completion to be delayed; this changes the
last state prior to completion to MIGRATE_STATUS_DEVICE rather
than MIGRATE_STATUS_ACTIVE.

Fix the failure path in migration_completion to recover the block
devices if it fails in MIGRATE_STATUS_DEVICE, not just the
MIGRATE_STATUS_ACTIVE that it previously had.

This corresponds to rh bz:
  https://bugzilla.redhat.com/show_bug.cgi?id=1538494
whose symptom is an occasional source crash on a failed migration.

Fixes: e91d8951d59d483f085f
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/migration.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/migration/migration.c b/migration/migration.c
index c99a4e62d7..a5e8bb4a78 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2122,7 +2122,8 @@ fail_invalidate:
     /* If not doing postcopy, vm_start() will be called: let's regain
      * control on images.
      */
-    if (s->state == MIGRATION_STATUS_ACTIVE) {
+    if (s->state == MIGRATION_STATUS_ACTIVE ||
+        s->state == MIGRATION_STATUS_DEVICE) {
         Error *local_err = NULL;
 
         qemu_mutex_lock_iothread();
-- 
2.14.3