[Qemu-devel] [PATCH v2 4/4] qmp: Add optional switch "query-nodes" in query-blockstats

[Fam Zheng <famz@redhat.com>]

This bool option will allow query all the node names. It iterates all
the BDSes that are assigned a name, also in this case don't query up the
backing chain.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/qapi.c         | 20 +++++++++++++-------
 hmp.c                |  2 +-
 qapi/block-core.json | 11 ++++++++++-
 qmp-commands.hx      |  2 +-
 4 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/block/qapi.c b/block/qapi.c
index a4d1a20..a0a50b9 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -322,7 +322,8 @@ static void bdrv_query_info(BlockBackend *blk, BlockInfo **p_info,
     qapi_free_BlockInfo(info);
 }
 
-static BlockStats *bdrv_query_stats(const BlockDriverState *bs)
+static BlockStats *bdrv_query_stats(const BlockDriverState *bs,
+                                    bool query_backing)
 {
     BlockStats *s;
 
@@ -352,12 +353,12 @@ static BlockStats *bdrv_query_stats(const BlockDriverState *bs)
 
     if (bs->file) {
         s->has_parent = true;
-        s->parent = bdrv_query_stats(bs->file);
+        s->parent = bdrv_query_stats(bs->file, query_backing);
     }
 
-    if (bs->backing_hd) {
+    if (query_backing && bs->backing_hd) {
         s->has_backing = true;
-        s->backing = bdrv_query_stats(bs->backing_hd);
+        s->backing = bdrv_query_stats(bs->backing_hd, query_backing);
     }
 
     return s;
@@ -388,17 +389,22 @@ BlockInfoList *qmp_query_block(Error **errp)
     return NULL;
 }
 
-BlockStatsList *qmp_query_blockstats(Error **errp)
+BlockStatsList *qmp_query_blockstats(bool has_query_nodes,
+                                     bool query_nodes,
+                                     Error **errp)
 {
     BlockStatsList *head = NULL, **p_next = &head;
     BlockDriverState *bs = NULL;
 
-     while ((bs = bdrv_next(bs))) {
+    /* Just to be safe if query_nodes is not always initialized */
+    query_nodes = has_query_nodes && query_nodes;
+
+    while ((bs = query_nodes ? bdrv_next_node(bs) : bdrv_next(bs))) {
         BlockStatsList *info = g_malloc0(sizeof(*info));
         AioContext *ctx = bdrv_get_aio_context(bs);
 
         aio_context_acquire(ctx);
-        info->value = bdrv_query_stats(bs);
+        info->value = bdrv_query_stats(bs, !query_nodes);
         aio_context_release(ctx);
 
         *p_next = info;
diff --git a/hmp.c b/hmp.c
index 63d7686..94b27df 100644
--- a/hmp.c
+++ b/hmp.c
@@ -403,7 +403,7 @@ void hmp_info_blockstats(Monitor *mon, const QDict *qdict)
 {
     BlockStatsList *stats_list, *stats;
 
-    stats_list = qmp_query_blockstats(NULL);
+    stats_list = qmp_query_blockstats(false, false, NULL);
 
     for (stats = stats_list; stats; stats = stats->next) {
         if (!stats->value->has_device) {
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 6b4b96c..db4e8e9 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -430,11 +430,20 @@
 #
 # Query the @BlockStats for all virtual block devices.
 #
+# @query-nodes: #optional If true, the command will query all the block nodes
+#               that have a node name, in a list which will include "parent"
+#               information, but not "backing".
+#               If false or omitted, the behavior is as before - query all the
+#               device backends, recursively including their "parent" and #
+#               "backing". (Since 2.3)
+#
 # Returns: A list of @BlockStats for each virtual block devices.
 #
 # Since: 0.14.0
 ##
-{ 'command': 'query-blockstats', 'returns': ['BlockStats'] }
+{ 'command': 'query-blockstats',
+  'data': { '*query-nodes': 'bool' },
+  'returns': ['BlockStats'] }
 
 ##
 # @BlockdevOnError:
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 1abd619..44bfb9e 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -2347,7 +2347,7 @@ EQMP
 
     {
         .name       = "query-blockstats",
-        .args_type  = "",
+        .args_type  = "query-nodes:b?",
         .mhandler.cmd_new = qmp_marshal_input_query_blockstats,
     },
 
-- 
1.9.3