qmp: Make Quorum error events more palatable.

Insert quorum QMP events documentation alphabetically.

Also change the "ret" errno value by an optional "error" being an strerror(-ret)
in the QUORUM_REPORT_BAD qmp event.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

block/quorum.c

@@ -200,11 +200,14 @@ static void quorum_report_bad(QuorumAIOCB *acb, char *node_name, int ret)
 {
     QObject *data;
     assert(node_name);
-    data = qobject_from_jsonf("{ 'ret': %d"
+    data = qobject_from_jsonf("{ 'node-name': %s"
-                              ", 'node-name': %s"
                               ", 'sector-num': %" PRId64
                               ", 'sectors-count': %d }",
-                              ret, node_name, acb->sector_num, acb->nb_sectors);
+                              node_name, acb->sector_num, acb->nb_sectors);
+    if (ret < 0) {
+        QDict *dict = qobject_to_qdict(data);
+        qdict_put(dict, "error", qstring_from_str(strerror(-ret)));
+    }
     monitor_protocol_event(QEVENT_QUORUM_REPORT_BAD, data);
     qobject_decref(data);
 }

docs/qmp/qmp-events.txt

@@ -225,6 +225,45 @@ Data:
   "timestamp": { "seconds": 1368697518, "microseconds": 326866 } }
 }
 
+QUORUM_FAILURE
+--------------
+
+Emitted by the Quorum block driver if it fails to establish a quorum.
+
+Data:
+
+- "reference":    device name if defined else node name.
+- "sector-num":   Number of the first sector of the failed read operation.
+- "sector-count": Failed read operation sector count.
+
+Example:
+
+{ "event": "QUORUM_FAILURE",
+     "data": { "reference": "usr1", "sector-num": 345435, "sector-count": 5 },
+     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }
+
+QUORUM_REPORT_BAD
+-----------------
+
+Emitted to report a corruption of a Quorum file.
+
+Data:
+
+- "error":        Error message (json-string, optional)
+                  Only present on failure.  This field contains a human-readable
+                  error message.  There are no semantics other than that the
+                  block layer reported an error and clients should not try to
+                  interpret the error string.
+- "node-name":    The graph node name of the block driver state.
+- "sector-num":   Number of the first sector of the failed read operation.
+- "sector-count": Failed read operation sector count.
+
+Example:
+
+{ "event": "QUORUM_REPORT_BAD",
+     "data": { "node-name": "1.raw", "sector-num": 345435, "sector-count": 5 },
+     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }
+
 RESET
 -----
 
@@ -500,39 +539,3 @@ Example:
 
 Note: If action is "reset", "shutdown", or "pause" the WATCHDOG event is
 followed respectively by the RESET, SHUTDOWN, or STOP events.
-
-QUORUM_FAILURE
---------------
-
-Emitted by the Quorum block driver if it fails to establish a quorum.
-
-Data:
-
-- "reference":    device name if defined else node name.
-- "sector-num":   Number of the first sector of the failed read operation.
-- "sector-count": Failed read operation sector count.
-
-Example:
-
-{ "event": "QUORUM_FAILURE",
-     "data": { "reference": "usr1", "sector-num": 345435, "sector-count": 5 },
-     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }
-
-QUORUM_REPORT_BAD
------------------
-
-Emitted to report a corruption of a Quorum file.
-
-Data:
-
-- "ret":          The IO return code.
-- "node-name":    The graph node name of the block driver state.
-- "sector-num":   Number of the first sector of the failed read operation.
-- "sector-count": Failed read operation sector count.
-
-Example:
-
-{ "event": "QUORUM_REPORT_BAD",
-     "data": { "ret": 0, "node-name": "1.raw", "sector-num": 345435,
-               "sector-count": 5 },
-     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }

tests/qemu-iotests/081.out

@@ -30,7 +30,7 @@ Testing: -drive file=TEST_DIR/2.IMGFMT,format=IMGFMT,if=none,id=drive2
 QMP_VERSION
 {"return": {}}
 {"return": {}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "QUORUM_REPORT_BAD", "data": {"node-name": "", "ret": 0, "sectors-count": 20480, "sector-num": 0}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "QUORUM_REPORT_BAD", "data": {"node-name": "", "sectors-count": 20480, "sector-num": 0}}
 read 10485760/10485760 bytes at offset 0
 10 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 {"return": ""}