block: more check for replaced node

We use mirror+replace to fix quorum's broken child. bs/s->common.bs
is quorum, and to_replace is the broken child. The new child is target_bs.
Without this patch, the replace node can be any node, and it can be
top BDS with BB, or another quorum's child. We just check if the broken
child is part of the quorum BDS in this patch.
Signed-off-by: NWen Congyang <wency@cn.fujitsu.com>
Message-id: 55A86486.1000404@cn.fujitsu.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

block.c

@@ -4077,7 +4077,8 @@ bool bdrv_is_first_non_filter(BlockDriverState *candidate)
     return false;
 }
 
-BlockDriverState *check_to_replace_node(const char *node_name, Error **errp)
+BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
+                                        const char *node_name, Error **errp)
 {
     BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
     AioContext *aio_context;
@@ -4100,7 +4101,7 @@ BlockDriverState *check_to_replace_node(const char *node_name, Error **errp)
      * Another benefit is that this tests exclude backing files which are
      * blocked by the backing blockers.
      */
-    if (!bdrv_is_first_non_filter(to_replace_bs)) {
+    if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
         error_setg(errp, "Only top most non filter can be replaced");
         to_replace_bs = NULL;
         goto out;

block/mirror.c

@@ -644,9 +644,9 @@ static void mirror_complete(BlockJob *job, Error **errp)
     if (s->replaces) {
         AioContext *replace_aio_context;
 
-        s->to_replace = check_to_replace_node(s->replaces, &local_err);
+        s->to_replace = bdrv_find_node(s->replaces);
         if (!s->to_replace) {
-            error_propagate(errp, local_err);
+            error_setg(errp, "Node name '%s' not found", s->replaces);
             return;
         }
 

blockdev.c

@@ -2760,7 +2760,7 @@ void qmp_drive_mirror(const char *device, const char *target,
             goto out;
         }
 
-        to_replace_bs = check_to_replace_node(replaces, &local_err);
+        to_replace_bs = check_to_replace_node(bs, replaces, &local_err);
 
         if (!to_replace_bs) {
             error_propagate(errp, local_err);

include/block/block.h

@@ -317,7 +317,8 @@ bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
 bool bdrv_is_first_non_filter(BlockDriverState *candidate);
 
 /* check if a named node can be replaced when doing drive-mirror */
-BlockDriverState *check_to_replace_node(const char *node_name, Error **errp);
+BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
+                                        const char *node_name, Error **errp);
 
 /* async block I/O */
 typedef void BlockDriverDirtyHandler(BlockDriverState *bs, int64_t sector,