block: BDRVReopenState: drop replace_backing_bs field

It's used only in bdrv_reopen_commit(). "backing" is covered by the
loop through all children except for case when we removed backing child
during reopen.

Make it more obvious and drop extra boolean field: qdict_del will not
fail if there is no such entry.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210610120537.196183-8-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

2 files changed, 4 insertions, 7 deletions

diff --git a/block.c b/block.c
index 0a73335380..ca11078cd2 100644
--- a/block.c
+++ b/block.c
@@ -4296,7 +4296,6 @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state,
         return -EINVAL;
     }
 
-    reopen_state->replace_backing_bs = true;
     reopen_state->old_backing_bs = bs->backing ? bs->backing->bs : NULL;
     return bdrv_set_backing_noperm(bs, new_backing_bs, set_backings_tran, errp);
 }
@@ -4550,17 +4549,16 @@ static void bdrv_reopen_commit(BDRVReopenState *reopen_state)
     bs->open_flags         = reopen_state->flags;
     bs->detect_zeroes      = reopen_state->detect_zeroes;
 
-    if (reopen_state->replace_backing_bs) {
-        qdict_del(bs->explicit_options, "backing");
-        qdict_del(bs->options, "backing");
-    }
-
     /* Remove child references from bs->options and bs->explicit_options.
      * Child options were already removed in bdrv_reopen_queue_child() */
     QLIST_FOREACH(child, &bs->children, next) {
         qdict_del(bs->explicit_options, child->name);
         qdict_del(bs->options, child->name);
     }
+    /* backing is probably removed, so it's not handled by previous loop */
+    qdict_del(bs->explicit_options, "backing");
+    qdict_del(bs->options, "backing");
+
     bdrv_refresh_limits(bs, NULL, NULL);
 }
 
diff --git a/include/block/block.h b/include/block/block.h
index 8e707a83b7..d28022e761 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -208,7 +208,6 @@ typedef struct BDRVReopenState {
     int flags;
     BlockdevDetectZeroesOptions detect_zeroes;
     bool backing_missing;
-    bool replace_backing_bs;  /* new_backing_bs is ignored if this is false */
     BlockDriverState *old_backing_bs; /* keep pointer for permissions update */
     QDict *options;
     QDict *explicit_options;