bdrv_requests_pending(), called by bdrv_requests_pending_all(), is the
function that determines for each of the disks in your VM if it still
has requests in flight that need to be completed. This function must
have returned true even though there is nothing to wait for.
Can you check which of its conditions led to this behaviour, and for
which disk it did? Either by setting a breakpoint there and
singlestepping through the function the next time it is called (if the
poll even has a timeout), or by inspecting the conditions manually in
gdb.
The condition that is true is:
if (!QLIST_EMPTY(&bs->tracked_requests))
and it's returned for intermediate qcow2 which is being commited.
--
mg
