[Qemu-devel] [PATCH 3/6] block: Introduce query-block-node

[Kevin Wolf <kwolf@redhat.com>]

This new command is a renamed version of query-named-block-nodes
with an additional argument that allows querying only one specific
BlockDriverState instead of getting a list for all of them.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c               | 15 +++++++++++++--
 blockdev.c            |  8 +++++++-
 include/block/block.h |  2 +-
 qapi/block-core.json  | 19 ++++++++++++++++---
 4 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/block.c b/block.c
index bcd952a..6c538d3 100644
--- a/block.c
+++ b/block.c
@@ -3823,13 +3823,24 @@ BlockDriverState *bdrv_find_node(const char *node_name)
 }
 
 /* Put this QMP function here so it can access the static graph_bdrv_states. */
-BlockDeviceInfoList *bdrv_named_nodes_list(void)
+BlockDeviceInfoList *bdrv_named_nodes_list(const char *device, Error **errp)
 {
     BlockDeviceInfoList *list, *entry;
     BlockDriverState *bs;
+    Error *local_err = NULL;
+
+    if (device) {
+        bs = bdrv_lookup_bs(device, device, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            return NULL;
+        }
+    } else {
+        bs = QTAILQ_FIRST(&graph_bdrv_states);
+    }
 
     list = NULL;
-    QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
+    for (; bs; bs = device ? NULL : QTAILQ_NEXT(bs, node_list)) {
         entry = g_malloc0(sizeof(*entry));
         entry->value = bdrv_block_device_info(bs);
         entry->next = list;
diff --git a/blockdev.c b/blockdev.c
index b361fbb..a194d04 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2127,9 +2127,15 @@ void qmp_drive_backup(const char *device, const char *target,
     }
 }
 
+BlockDeviceInfoList *qmp_query_block_node(bool has_device, const char *device,
+                                          Error **errp)
+{
+    return bdrv_named_nodes_list(has_device ? device : NULL, errp);
+}
+
 BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
 {
-    return bdrv_named_nodes_list();
+    return qmp_query_block_node(false, NULL, errp);
 }
 
 #define DEFAULT_MIRROR_BUF_SIZE   (10 << 20)
diff --git a/include/block/block.h b/include/block/block.h
index 07d6d8e..0caab0d 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -403,7 +403,7 @@ void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 const char *bdrv_get_format_name(BlockDriverState *bs);
 BlockDriverState *bdrv_find(const char *name);
 BlockDriverState *bdrv_find_node(const char *node_name);
-BlockDeviceInfoList *bdrv_named_nodes_list(void);
+BlockDeviceInfoList *bdrv_named_nodes_list(const char *device, Error **errp);
 BlockDriverState *bdrv_lookup_bs(const char *device,
                                  const char *node_name,
                                  Error **errp);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index ddc3fe0..f170c7e 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -797,13 +797,26 @@
 ##
 # @query-named-block-nodes
 #
-# Get the named block driver list
+# Deprecated, may be removed in future versions. Use query-block-node instead.
+#
+# Since 2.0, until 2.1
+##
+{ 'command': 'query-named-block-nodes', 'returns': [ 'BlockDeviceInfo' ] }
+
+##
+# @query-block-node
+#
+# Gets information about one or all block device nodes.
+#
+# @device: #optional The id or node-name of the block device to inspect.
 #
 # Returns: the list of BlockDeviceInfo
 #
-# Since 2.0
+# Since 2.2
 ##
-{ 'command': 'query-named-block-nodes', 'returns': [ 'BlockDeviceInfo' ] }
+{ 'command': 'query-block-node',
+  'data': { '*device': 'str' },
+  'returns': [ 'BlockDeviceInfo' ] }
 
 ##
 # @drive-mirror
-- 
1.8.3.1