[Qemu-devel] [PATCH 10/15] qmp: add query-block-jobs command

[Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>]

Active image streaming operations can be enumerated with the
query-block-jobs command.  Each operation is listed along with its
total progress.

The command synopsis is:

query-block-jobs
----------------

Show progress of ongoing block device operations.

Return a json-array of all block device operations.  If no operation is
active then return an empty array.  Each operation is a json-object with
the following data:

- type:     job type ("stream" for image streaming, json-string)
- device:   device name (json-string)
- end:      maximum progress value (json-int)
- position: current progress value (json-int)
- speed:    rate limit, bytes per second (json-int)

Progress can be observed as position increases and it reaches end when
the operation completes.  Position and end have undefined units but can
be used to calculate a percentage indicating the progress that has been
made.

Example:

-> { "execute": "query-block-jobs" }
<- { "return":[
      { "type": "stream", "device": "virtio0",
        "end": 10737418240, "position": 709632,
        "speed": 0 }
   ]
 }

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 blockdev.c      |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 blockdev.h      |    2 ++
 hmp-commands.hx |    2 ++
 monitor.c       |   16 ++++++++++++++++
 qmp-commands.hx |   31 +++++++++++++++++++++++++++++++
 5 files changed, 97 insertions(+), 0 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index e9bc577..422b43b 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -802,6 +802,52 @@ out:
     return ret;
 }
 
+static void monitor_print_block_stream(Monitor *mon, const QObject *data)
+{
+    QDict *stream;
+
+    assert(data);
+    stream = qobject_to_qdict(data);
+
+    monitor_printf(mon, "Streaming device %s: Completed %" PRId64 " of %"
+                   PRId64 " bytes, speed limit %" PRId64 " bytes/s\n",
+                   qdict_get_str(stream, "device"),
+                   qdict_get_int(stream, "offset"),
+                   qdict_get_int(stream, "len"),
+                   (int64_t)0);
+}
+
+void monitor_print_block_jobs(Monitor *mon, const QObject *data)
+{
+    QList *streams;
+    QListEntry *entry;
+
+    assert(data);
+    streams = qobject_to_qlist(data);
+    assert(streams); /* we pass a list of stream objects to ourselves */
+
+    if (qlist_empty(streams)) {
+        monitor_printf(mon, "No active jobs\n");
+        return;
+    }
+
+    QLIST_FOREACH_ENTRY(streams, entry) {
+        monitor_print_block_stream(mon, entry->value);
+    }
+}
+
+void do_info_block_jobs(Monitor *mon, QObject **ret_data)
+{
+    QList *streams;
+    StreamState *s;
+
+    streams = qlist_new();
+    QLIST_FOREACH(s, &block_streams, list) {
+        qlist_append_obj(streams, stream_get_qobject(s));
+    }
+    *ret_data = QOBJECT(streams);
+}
+
 int do_block_stream(Monitor *mon, const QDict *params, QObject **ret_data)
 {
     const char *device = qdict_get_str(params, "device");
diff --git a/blockdev.h b/blockdev.h
index a3cde69..0a32793 100644
--- a/blockdev.h
+++ b/blockdev.h
@@ -66,6 +66,8 @@ int do_change_block(Monitor *mon, const char *device,
 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data);
 int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data);
 int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data);
+void monitor_print_block_jobs(Monitor *mon, const QObject *data);
+void do_info_block_jobs(Monitor *mon, QObject **ret_data);
 int do_block_stream(Monitor *mon, const QDict *params, QObject **ret_data);
 int do_block_job_cancel(Monitor *mon, const QDict *params,
                         MonitorCompletion cb, void *opaque);
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 613eb76..74a74d8 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1383,6 +1383,8 @@ show device tree
 show qdev device model list
 @item info roms
 show roms
+@item info block-jobs
+show progress of background block device operations
 @end table
 ETEXI
 
diff --git a/monitor.c b/monitor.c
index 700b534..bc2f630 100644
--- a/monitor.c
+++ b/monitor.c
@@ -3141,6 +3141,14 @@ static const mon_cmd_t info_cmds[] = {
     },
 #endif
     {
+        .name       = "block-jobs",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show block job status",
+        .user_print = monitor_print_block_jobs,
+        .mhandler.info_new = do_info_block_jobs,
+    },
+    {
         .name       = NULL,
     },
 };
@@ -3282,6 +3290,14 @@ static const mon_cmd_t qmp_query_cmds[] = {
         .mhandler.info_async = do_info_balloon,
         .flags      = MONITOR_CMD_ASYNC,
     },
+    {
+        .name       = "block-jobs",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show block job status",
+        .user_print = monitor_print_block_jobs,
+        .mhandler.info_new = do_info_block_jobs,
+    },
     { /* NULL */ },
 };
 
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 5ab15a4..c3a72ad 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1971,3 +1971,34 @@ Example:
 
 EQMP
 
+SQMP
+query-block-jobs
+----------------
+
+Show progress of ongoing block device operations.
+
+Return a json-array of all block device operations.  If no operation is
+active then return an empty array.  Each operation is a json-object with the
+following data:
+
+- type:     job type ("stream" for image streaming, json-string)
+- device:   device name (json-string)
+- end:      maximum progress value (json-int)
+- position: current progress value (json-int)
+- speed:    rate limit, bytes per second (json-int)
+
+Progress can be observed as position increases and it reaches end when
+the operation completes.  Position and end have undefined units but can be
+used to calculate a percentage indicating the progress that has been made.
+
+Example:
+
+-> { "execute": "query-block-jobs" }
+<- { "return":[
+      { "type": "stream", "device": "virtio0",
+        "end": 10737418240, "position": 709632,
+        "speed": 0 }
+   ]
+ }
+
+EQMP
-- 
1.7.5.4