mirror: Double-check immediately before replacing

There is no guarantee that we can still replace the node we want to
replace at the end of the mirror job.  Double-check by calling
bdrv_recurse_can_replace().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200218103454.296704-12-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2020-02-18 11:34:46 +01:00 committed by Kevin Wolf
parent 6b4907cf42
commit 6e9cc05181

View File

@ -700,7 +700,19 @@ static int mirror_exit_common(Job *job)
* drain potential other users of the BDS before changing the graph. */
assert(s->in_drain);
bdrv_drained_begin(target_bs);
bdrv_replace_node(to_replace, target_bs, &local_err);
/*
* Cannot use check_to_replace_node() here, because that would
* check for an op blocker on @to_replace, and we have our own
* there.
*/
if (bdrv_recurse_can_replace(src, to_replace)) {
bdrv_replace_node(to_replace, target_bs, &local_err);
} else {
error_setg(&local_err, "Can no longer replace '%s' by '%s', "
"because it can no longer be guaranteed that doing so "
"would not lead to an abrupt change of visible data",
to_replace->node_name, target_bs->node_name);
}
bdrv_drained_end(target_bs);
if (local_err) {
error_report_err(local_err);