diff mbox series

[v4,11/19] mirror: Double-check immediately before replacing

Message ID 20200218103454.296704-12-mreitz@redhat.com
State New
Headers show
Series block: Fix check_to_replace_node() | expand

Commit Message

Max Reitz Feb. 18, 2020, 10:34 a.m. UTC 
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>
---
 block/mirror.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/block/mirror.c b/block/mirror.c
index cacbc70014..447051dbc6 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -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);