Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2017-07-24' into staging

[qemu.git] / blockdev.c

diff --git a/blockdev.c b/blockdev.c
index 7f53cc8bb3d430127217b095fb65a9bd3e1f67d6..02cd69bc21ad9859c6bfe72d14ee5a3c8fe1a19d 100644 (file)
--- a/blockdev.c
+++ b/blockdev.c
@@ -1710,7 +1710,8 @@ static void external_snapshot_prepare(BlkActionState *common,
         }
 
         flags = state->old_bs->open_flags;
-        flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ);
+        flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_COPY_ON_READ);
+        flags |= BDRV_O_NO_BACKING;
 
         /* create new image w/backing file */
         mode = s->has_mode ? s->mode : NEW_IMAGE_MODE_ABSOLUTE_PATHS;
@@ -1735,8 +1736,6 @@ static void external_snapshot_prepare(BlkActionState *common,
             qdict_put_str(options, "node-name", snapshot_node_name);
         }
         qdict_put_str(options, "driver", format);
-
-        flags |= BDRV_O_NO_BACKING;
     }
 
     state->new_bs = bdrv_open(new_image_file, snapshot_ref, options, flags,
@@ -3548,6 +3547,9 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
         backing_mode = MIRROR_OPEN_BACKING_CHAIN;
     }
 
+    /* Don't open backing image in create() */
+    flags |= BDRV_O_NO_BACKING;
+
     if ((arg->sync == MIRROR_SYNC_MODE_FULL || !source)
         && arg->mode != NEW_IMAGE_MODE_EXISTING)
     {
@@ -3587,8 +3589,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
     /* Mirroring takes care of copy-on-write using the source's backing
      * file.
      */
-    target_bs = bdrv_open(arg->target, NULL, options,
-                          flags | BDRV_O_NO_BACKING, errp);
+    target_bs = bdrv_open(arg->target, NULL, options, flags, errp);
     if (!target_bs) {
         goto out;
     }
@@ -3886,6 +3887,7 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
     QObject *obj;
     Visitor *v = qobject_output_visitor_new(&obj);
     QDict *qdict;
+    const QDictEntry *ent;
     Error *local_err = NULL;
 
     visit_type_BlockdevOptions(v, NULL, &options, &local_err);
@@ -3899,6 +3901,19 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
 
     qdict_flatten(qdict);
 
+    /*
+     * Rewrite "backing": null to "backing": ""
+     * TODO Rewrite "" to null instead, and perhaps not even here
+     */
+    for (ent = qdict_first(qdict); ent; ent = qdict_next(qdict, ent)) {
+        char *dot = strrchr(ent->key, '.');
+
+        if (!strcmp(dot ? dot + 1 : ent->key, "backing")
+            && qobject_type(ent->value) == QTYPE_QNULL) {
+            qdict_put(qdict, ent->key, qstring_new());
+        }
+    }
+
     if (!qdict_get_try_str(qdict, "node-name")) {
         error_setg(errp, "'node-name' must be specified for the root node");
         goto fail;