block: Add replaces argument to drive-mirror

drive-mirror will bdrv_swap the new BDS named node-name with the one
pointed by replaces when the mirroring is finished.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 30 insertions, 1 deletions

diff --git a/blockdev.c b/blockdev.c
index 943301226d..69b7c2a8c5 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2100,6 +2100,7 @@ BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
 void qmp_drive_mirror(const char *device, const char *target,
                       bool has_format, const char *format,
                       bool has_node_name, const char *node_name,
+                      bool has_replaces, const char *replaces,
                       enum MirrorSyncMode sync,
                       bool has_mode, enum NewImageMode mode,
                       bool has_speed, int64_t speed,
@@ -2187,6 +2188,29 @@ void qmp_drive_mirror(const char *device, const char *target,
         return;
     }
 
+    if (has_replaces) {
+        BlockDriverState *to_replace_bs;
+
+        if (!has_node_name) {
+            error_setg(errp, "a node-name must be provided when replacing a"
+                             " named node of the graph");
+            return;
+        }
+
+        to_replace_bs = check_to_replace_node(replaces, &local_err);
+
+        if (!to_replace_bs) {
+            error_propagate(errp, local_err);
+            return;
+        }
+
+        if (size != bdrv_getlength(to_replace_bs)) {
+            error_setg(errp, "cannot replace image with a mirror image of "
+                             "different size");
+            return;
+        }
+    }
+
     if ((sync == MIRROR_SYNC_MODE_FULL || !source)
         && mode != NEW_IMAGE_MODE_EXISTING)
     {
@@ -2231,7 +2255,12 @@ void qmp_drive_mirror(const char *device, const char *target,
         return;
     }
 
-    mirror_start(bs, target_bs, speed, granularity, buf_size, sync,
+    /* pass the node name to replace to mirror start since it's loose coupling
+     * and will allow to check whether the node still exist at mirror completion
+     */
+    mirror_start(bs, target_bs,
+                 has_replaces ? replaces : NULL,
+                 speed, granularity, buf_size, sync,
                  on_source_error, on_target_error,
                  block_job_cb, bs, &local_err);
     if (local_err != NULL) {