[Qemu-devel] [PATCH 2/6] block: Add optional device argument to query-block

[Kevin Wolf <kwolf@redhat.com>]

This allows querying one specific BlockDriverState instead of a list of
all drives.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/qapi.c         | 15 +++++++++++++--
 hmp.c                |  6 +++---
 qapi/block-core.json |  8 ++++++--
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/block/qapi.c b/block/qapi.c
index 6b43bc3..2a060d3 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -367,13 +367,24 @@ static BlockStats *bdrv_query_stats(const BlockDriverState *bs)
     return s;
 }
 
-BlockInfoList *qmp_query_block(Error **errp)
+BlockInfoList *qmp_query_block(bool has_device, const char *device,
+                               Error **errp)
 {
     BlockInfoList *head = NULL, **p_next = &head;
     BlockDriverState *bs = NULL;
     Error *local_err = NULL;
 
-     while ((bs = bdrv_next(bs))) {
+    if (has_device) {
+        bs = bdrv_find(device);
+        if (bs == NULL) {
+            error_setg(errp, "Device not found");
+            goto err;
+        }
+    } else {
+        bs = bdrv_next(NULL);
+    }
+
+    for (; bs; (bs = has_device ? NULL : bdrv_next(bs))) {
         BlockInfoList *info = g_malloc0(sizeof(*info));
         bdrv_query_info(bs, &info->value, &local_err);
         if (local_err) {
diff --git a/hmp.c b/hmp.c
index c3846b8..02eee80 100644
--- a/hmp.c
+++ b/hmp.c
@@ -298,7 +298,7 @@ void hmp_info_block(Monitor *mon, const QDict *qdict)
     const char *device = qdict_get_try_str(qdict, "device");
     bool verbose = qdict_get_try_bool(qdict, "verbose", 0);
 
-    block_list = qmp_query_block(NULL);
+    block_list = qmp_query_block(false, NULL, NULL);
 
     for (info = block_list; info; info = info->next) {
         if (device && strcmp(device, info->value->device)) {
@@ -847,7 +847,7 @@ void hmp_cont(Monitor *mon, const QDict *qdict)
     BlockInfoList *bdev_list, *bdev;
     Error *err = NULL;
 
-    bdev_list = qmp_query_block(NULL);
+    bdev_list = qmp_query_block(false, NULL, NULL);
     for (bdev = bdev_list; bdev; bdev = bdev->next) {
         if (key_is_missing(bdev->value)) {
             monitor_read_block_device_key(mon, bdev->value->device,
@@ -1588,7 +1588,7 @@ void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
     /* Then try adding all block devices.  If one fails, close all and
      * exit.
      */
-    block_list = qmp_query_block(NULL);
+    block_list = qmp_query_block(false, NULL, NULL);
 
     for (info = block_list; info; info = info->next) {
         if (!info->value->has_inserted) {
diff --git a/qapi/block-core.json b/qapi/block-core.json
index c53b587..ddc3fe0 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -354,13 +354,17 @@
 ##
 # @query-block:
 #
-# Get a list of BlockInfo for all virtual block devices.
+# Get a list of BlockInfo for all or one specific virtual block device.
+#
+# @device: #optional The id of the block device to inspect. (Since 2.2)
 #
 # Returns: a list of @BlockInfo describing each virtual block device
 #
 # Since: 0.14.0
 ##
-{ 'command': 'query-block', 'returns': ['BlockInfo'] }
+{ 'command': 'query-block',
+  'data': { '*device': 'str' },
+  'returns': ['BlockInfo'] }
 
 ##
 # @BlockDeviceStats:
-- 
1.8.3.1