[Qemu-devel] [PATCH V8 11/20] qmp: add interface query-images

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

  This mirror function will return image info including snapshots,
if specified backing image's info will also be returned. Now Qemu
have both query-images and query-block interfaces.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
---
 block/qapi.c     |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 qapi-schema.json |   33 ++++++++++++++++++++
 qmp-commands.hx  |   86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 202 insertions(+), 0 deletions(-)

diff --git a/block/qapi.c b/block/qapi.c
index b903dd8..a67d380 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -202,3 +202,86 @@ SnapshotInfoList *qmp_query_snapshots(Error **errp)
     }
     return list;
 }
+
+/* Collect all info for one bs, p_list point to the empty tail to be filled,
+   return the empty tail of the new list. @bs must be the top one. */
+static DeviceImageInfoList **
+collect_device_image_info_list(BlockDriverState *bs,
+                               bool show_backing,
+                               DeviceImageInfoList **p_list,
+                               Error **errp)
+{
+    DeviceImageInfoList **p_next = p_list;
+    char *device_name = bs->device_name;
+
+    while (bs) {
+        DeviceImageInfo *dii = g_malloc0(sizeof(*dii));
+        DeviceImageInfoList *diil = g_malloc0(sizeof(*diil));
+        diil->value = dii;
+        *p_next = diil;
+        p_next = &diil->next;
+
+        dii->device = g_strdup(device_name);
+        if (!bdrv_is_inserted(bs)) {
+            dii->has_image = false;
+            break;
+        }
+        dii->has_image = true;
+        if (bdrv_query_image_info(bs, &dii->image, errp)) {
+            break;
+        }
+
+        if (show_backing && bs->drv && bs->backing_hd) {
+            bs = bs->backing_hd;
+        } else {
+            bs = NULL;
+        }
+    }
+    return p_next;
+}
+
+DeviceImageInfoList *qmp_query_images(bool has_device,
+                                      const char *device,
+                                      bool has_backing,
+                                      bool backing,
+                                      Error **errp)
+{
+    DeviceImageInfoList *head = NULL, **p_next = &head;
+    BlockDriverState *bs = NULL;
+    Error *err = NULL;
+    const char *target_device = NULL;
+    bool show_backing = false;
+
+    if (has_device) {
+        target_device = device;
+    }
+    if (has_backing) {
+        show_backing = backing;
+    }
+
+    if (target_device) {
+        bs = bdrv_find(device);
+        if (!bs) {
+            error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+            return NULL;
+        }
+        collect_device_image_info_list(bs, show_backing, p_next, errp);
+        if (error_is_set(&err)) {
+            goto err;
+        }
+    } else {
+        while ((bs = bdrv_next(bs))) {
+            p_next = collect_device_image_info_list(bs, show_backing,
+                                                    p_next, errp);
+            if (error_is_set(&err)) {
+                goto err;
+            }
+        }
+    }
+
+    return head;
+
+ err:
+    qapi_free_DeviceImageInfoList(head);
+    return NULL;
+}
diff --git a/qapi-schema.json b/qapi-schema.json
index 3710495..71a9eba 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -294,6 +294,21 @@
            '*total-clusters': 'int', '*allocated-clusters': 'int',
            '*fragmented-clusters': 'int', '*compressed-clusters': 'int' } }
 
+# @DeviceImageInfo:
+#
+# Information about an image used by a QEMU block device
+#
+# @device: name of the block device
+#
+# @image: #optional info of the image used
+#
+# Since: 1.5
+#
+##
+
+{ 'type': 'DeviceImageInfo',
+  'data': {'device': 'str', '*image': 'ImageInfo' } }
+
 ##
 # @StatusInfo:
 #
@@ -853,6 +868,24 @@
   'returns': ['SnapshotInfo'] }
 
 ##
+# @query-images:
+#
+# Get block device image information
+#
+# @device: #optional the name of the device to get image info from. If not
+#          specified, all block devices will be queried
+# @backing: #optional true to show information on backing images, false or
+#          omitted to show just the top image of a block device
+#
+# Returns: a list of @DeviceImageInfo describing each virtual block device
+#
+# Since: 1.5
+##
+{ 'command': 'query-images',
+  'data': { '*device': 'str', '*backing': 'bool' },
+  'returns': ['DeviceImageInfo'] }
+
+##
 # @BlockDeviceStats:
 #
 # Statistics of a virtual block device or a block backing device.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index d505209..f0482c2 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1798,6 +1798,92 @@ EQMP
     },
 
 SQMP
+query-images
+-----------
+
+Show block device image information
+
+Each device is represented by a json-object. The returned value is a json-array
+of all devices' images
+
+Each json-object contain the following:
+
+- "device": device name (json-string)
+- "image": image information(json-object, optional) containing:
+         - "filename": image file name (json-string)
+         - "format": image format (json-string)
+         - "virtual-size": image capacity in bytes (json-int)
+         - "dirty-flag": true if image is not cleanly closed, not present means
+                         clean (json-bool, optional)
+         - "actual-size": actual size on disk in bytes of the image, not
+                          present when image does not support thin provision
+                          (json-int, optional)
+         - "cluster-size": size of a cluster in bytes, only present when image
+                           format support cluster (json-int, optional)
+         - "encrypted": true if the image is encrypted, only present when image
+                        support encryption (json-bool, optional)
+         - "backing_file": backing file name, only present when image format
+                           support backing file chain (json-string, optional)
+         - "full-backing-filename": full path of the backing file
+                                    (json-string, optional)
+         - "backing-filename-format": the format of the backing file
+                                      (json-string, optional)
+         - "snapshots": the internal snapshot info, it is an optional list of
+            json-object containing the following:
+             - "id": unique snapshot id (json-string)
+             - "name": snapshot name (json-string)
+             - "vm-state-size": size of the VM state in bytes (json-int)
+             - "date-sec": UTC date of the snapshot in seconds (json-int)
+             - "date-nsec": fractional part in nano seconds to be used with
+                            date-sec(json-int)
+             - "vm-clock-sec": VM clock relative to boot in seconds (json-int)
+             - "vm-clock-nsec": fractional part in nano seconds to be used with
+                                vm-clock-sec (json-int)
+
+Example:
+
+-> { "execute": "query-images" }
+<- {
+      "return":[
+         {
+            "device":"ide0-hd0",
+            "image":{
+               "filename":"disks/test0.img",
+               "format":"qcow2",
+               "virtual-size":1024000
+            }
+         },
+         {
+            "device":"ide0-hd1",
+            "image":{
+               "filename":"disks/test1.img",
+               "format":"qcow2",
+               "virtual-size":2048000,
+               "snapshots":[
+                  {
+                     "id": "1",
+                     "name": "snapshot1",
+                     "vm-state-size": 0,
+                     "date-sec": 10000200,
+                     "date-nsec": 12,
+                     "vm-clock-sec": 206,
+                     "vm-clock-nsec": 30
+                  }
+               ]
+            }
+         }
+      ]
+   }
+
+EQMP
+
+    {
+        .name       = "query-images",
+        .args_type  = "device:B?, backing:-b",
+        .mhandler.cmd_new = qmp_marshal_input_query_images,
+    },
+
+SQMP
 query-blockstats
 ----------------
 
-- 
1.7.1