The block job holds a reference to the backup-top node (because it is
passed as the main job BDS to block_job_create()). Therefore,
bdrv_backup_top_drop() cannot delete the backup-top node (replacing it
by its child does not affect the job parent, because that has
.stay_at_node set). That is a problem, because all of its I/O functions
assume the BlockCopyState (s->bcs) to be valid and that it has a
filtered child; but after bdrv_backup_top_drop(), neither of those
things are true.
It does not make sense to add new parents to backup-top after
backup_clean(), so we should detach it from the job before
bdrv_backup_top_drop(). Because there is no function to do that for a
single node, just detach all of the job's nodes -- the job does not do
anything past backup_clean() anyway.
Signed-off-by: Max Reitz <mre...@redhat.com>
---
block/backup.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/block/backup.c b/block/backup.c
index 94e6dcd72e..6cf2f974aa 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -103,6 +103,7 @@ static void backup_abort(Job *job)
static void backup_clean(Job *job)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
+ block_job_remove_all_bdrv(&s->common);
bdrv_backup_top_drop(s->backup_top);
}
--
2.29.2
