migration/block-dirty-bitmap: cancel migration on shutdown

If target is turned off prior to postcopy finished, target crashes
because busy bitmaps are found at shutdown.
Canceling incoming migration helps, as it removes all unfinished (and
therefore busy) bitmaps.

Similarly on source we crash in bdrv_close_all which asserts that all
bdrv states are removed, because bdrv states involved into dirty bitmap
migration are referenced by it. So, we need to cancel outgoing
migration as well.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Message-Id: <20200727194236.19551-17-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c
index f91015a4f8..1f675b792f 100644
--- a/migration/block-dirty-bitmap.c
+++ b/migration/block-dirty-bitmap.c
@@ -657,6 +657,22 @@ static void cancel_incoming_locked(DBMLoadState *s)
     s->bitmaps = NULL;
 }
 
+void dirty_bitmap_mig_cancel_outgoing(void)
+{
+    dirty_bitmap_do_save_cleanup(&dbm_state.save);
+}
+
+void dirty_bitmap_mig_cancel_incoming(void)
+{
+    DBMLoadState *s = &dbm_state.load;
+
+    qemu_mutex_lock(&s->lock);
+
+    cancel_incoming_locked(s);
+
+    qemu_mutex_unlock(&s->lock);
+}
+
 static void dirty_bitmap_load_complete(QEMUFile *f, DBMLoadState *s)
 {
     GSList *item;