[Qemu-devel] [PATCH V3 6/9] qmp: add interface blockdev-snapshot-delete-internal-sync

[Wenchao Xia]

This interface use id and name as optional parameters, to handle the
case that one image contain multiple snapshots with same name which
may be '', but with different id.

Adding parameter id is for historical compatiability reason, and
that case is not possible in qemu's new interface for internal
snapshot at block device level, but still possible in qemu-img.

Signed-off-by: Wenchao Xia <address@hidden>
---
 blockdev.c       |   61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 qapi-schema.json |   27 +++++++++++++++++++++++
 qmp-commands.hx  |   41 ++++++++++++++++++++++++++++++++++++
 3 files changed, 129 insertions(+), 0 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index ce89f83..35fffd6 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -790,6 +790,67 @@ void qmp_blockdev_snapshot_internal_sync(const char 
*device,
                        &snapshot, errp);
 }
 
+SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
+                                                         bool has_id,
+                                                         const char *id,
+                                                         bool has_name,
+                                                         const char *name,
+                                                         Error **errp)
+{
+    BlockDriverState *bs = bdrv_find(device);
+    QEMUSnapshotInfo sn;
+    Error *local_err = NULL;
+    SnapshotInfo *info = NULL;
+    int ret;
+
+    if (!bs) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        return NULL;
+    };
+
+    if (!has_id) {
+        id = NULL;
+    }
+
+    if (!has_name) {
+        name = NULL;
+    }
+
+    if (!id && !name) {
+        error_setg(errp, "Name or id must be provided");
+        return NULL;
+    }
+
+    ret = bdrv_snapshot_find_by_id_and_name(bs, id, name, &sn, &local_err);
+    if (error_is_set(&local_err)) {
+        error_propagate(errp, local_err);
+        return NULL;
+    }
+    if (!ret) {
+        error_setg(errp,
+                   "Snapshot with id '%s' and name '%s' do not exist on "
+                   "device '%s'",
+                   STR_PRINT_CHAR(id), STR_PRINT_CHAR(name), device);
+        return NULL;
+    }
+
+    bdrv_snapshot_delete(bs, id, name, &local_err);
+    if (error_is_set(&local_err)) {
+        error_propagate(errp, local_err);
+        return NULL;
+    }
+
+    info = g_malloc0(sizeof(SnapshotInfo));
+    info->id = g_strdup(sn.id_str);
+    info->name = g_strdup(sn.name);
+    info->date_nsec = sn.date_nsec;
+    info->date_sec = sn.date_sec;
+    info->vm_state_size = sn.vm_state_size;
+    info->vm_clock_nsec = sn.vm_clock_nsec % 1000000000;
+    info->vm_clock_sec = sn.vm_clock_nsec / 1000000000;
+
+    return info;
+}
 
 /* New and old BlockDriverState structs for group snapshots */
 
diff --git a/qapi-schema.json b/qapi-schema.json
index fba9b15..ffcdca7 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1760,6 +1760,33 @@
   'data': { 'device': 'str', 'name': 'str'} }
 
 ##
+# @blockdev-snapshot-delete-internal-sync
+#
+# Synchronously delete an internal snapshot of a block device, when the format
+# of the image used support it. The snapshot is identified by name or id or
+# both. One of the name or id is required. It will returns SnapshotInfo of
+# successfully deleted snapshot.
+#
+# @device: the name of the device to delete the snapshot from
+#
+# @id: optional the snapshot's ID to be deleted
+#
+# @name: optional the snapshot's name to be deleted
+#
+# Returns: SnapshotInfo on success
+#          If @device is not a valid block device, DeviceNotFound
+#          If snapshot not found, GenericError
+#          If the format of the image used does not support it,
+#          BlockFormatFeatureNotSupported
+#          If @id and @name are both not specified, GenericError
+#
+# Since 1.6
+##
+{ 'command': 'blockdev-snapshot-delete-internal-sync',
+  'data': { 'device': 'str', '*id': 'str', '*name': 'str'},
+  'returns': 'SnapshotInfo' }
+
+##
 # @human-monitor-command:
 #
 # Execute a command on the human monitor and return the output.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 3df50de..71260c9 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1121,6 +1121,47 @@ Example:
 EQMP
 
     {
+        .name       = "blockdev-snapshot-delete-internal-sync",
+        .args_type  = "device:B,id:s?,name:s?",
+        .mhandler.cmd_new =
+                      qmp_marshal_input_blockdev_snapshot_delete_internal_sync,
+    },
+
+SQMP
+blockdev-snapshot-delete-internal-sync
+--------------------------------------
+
+Synchronously delete an internal snapshot of a block device when the format of
+image used support it.  The snapshot is identified by name or id or both.  One
+of the name or id is required.  If the snapshot is not found, operation will
+fail.
+
+Arguments:
+
+- "device": device name (json-string)
+- "id": ID of the snapshot (json-string, optional)
+- "name": name of the snapshot (json-string, optional)
+
+Example:
+
+-> { "execute": "blockdev-snapshot-delete-internal-sync",
+                "arguments": { "device": "ide-hd0",
+                               "name": "snapshot0" }
+   }
+<- { "return": {
+                   "id": "1",
+                   "name": "snapshot0",
+                   "vm-state-size": 0,
+                   "date-sec": 1000012,
+                   "date-nsec": 10,
+                   "vm-clock-sec": 100,
+                   "vm-clock-nsec": 20
+     }
+   }
+
+EQMP
+
+    {
         .name       = "drive-mirror",
         .args_type  = "sync:s,device:B,target:s,speed:i?,mode:s?,format:s?,"
                       "on-source-error:s?,on-target-error:s?,"
-- 
1.7.1