[Qemu-devel] [PATCH 2/2] QMP: Introduce DISK_ERROR event

[Luiz Capitulino <lcapitulino@redhat.com>]

It's emitted when a disk write or read fails, some device information
is provided. We can also provide error details in the future.

Example:

{ "event": "DISK_ERROR",
    "data": { "device": "ide0-hd1",
              "operation": "write",
              "action": "stop" }
    "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

NOTE: Adding a small reference in QMP/qmp-events.txt, but this file is
wrong and will be replaced by proper documentation shortly.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
---
 QMP/qmp-events.txt |    7 +++++++
 monitor.c          |    3 +++
 monitor.h          |    1 +
 vl.c               |   34 +++++++++++++++++++++++++++++++++-
 4 files changed, 44 insertions(+), 1 deletions(-)

diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
index dc48ccc..e968ef5 100644
--- a/QMP/qmp-events.txt
+++ b/QMP/qmp-events.txt
@@ -43,3 +43,10 @@ Data: 'server' and 'client' keys with the same keys as 'query-vnc'.
 
 Description: Issued when the VNC session is made active.
 Data: 'server' and 'client' keys with the same keys as 'query-vnc'.
+
+7 DISK_ERROR
+------------
+
+Description: Issued when a disk I/O error occurs
+Data: 'device' (device name), 'action' (action to be taken),
+      'operation' ("read" or "write")
diff --git a/monitor.c b/monitor.c
index fb7c572..82edd79 100644
--- a/monitor.c
+++ b/monitor.c
@@ -378,6 +378,9 @@ void monitor_protocol_event(MonitorEvent event, QObject *data)
         case QEVENT_VNC_DISCONNECTED:
             event_name = "VNC_DISCONNECTED";
             break;
+        case QEVENT_DISK_ERROR:
+            event_name = "DISK_ERROR";
+            break;
         default:
             abort();
             break;
diff --git a/monitor.h b/monitor.h
index b0f9270..beaddaf 100644
--- a/monitor.h
+++ b/monitor.h
@@ -23,6 +23,7 @@ typedef enum MonitorEvent {
     QEVENT_VNC_CONNECTED,
     QEVENT_VNC_INITIALIZED,
     QEVENT_VNC_DISCONNECTED,
+    QEVENT_DISK_ERROR,
     QEVENT_MAX,
 } MonitorEvent;
 
diff --git a/vl.c b/vl.c
index 57c439d..1f69f56 100644
--- a/vl.c
+++ b/vl.c
@@ -1856,10 +1856,42 @@ static BlockInterfaceErrorAction drive_get_err_action(
     return is_read ? BLOCK_ERR_REPORT : BLOCK_ERR_STOP_ENOSPC;
 }
 
+static void driver_err_event(
+    BlockInterfaceErrorAction action, int is_read, const char *device)
+{
+    QObject *data;
+    const char *action_str;
+
+    switch (action) {
+    case BLOCK_ERR_REPORT:
+        action_str = "report";
+        break;
+    case BLOCK_ERR_IGNORE:
+        action_str = "ignore";
+        break;
+    case BLOCK_ERR_STOP_ANY:
+    case BLOCK_ERR_STOP_ENOSPC:
+        action_str = "stop";
+        break;
+    default:
+        abort();
+    }
+
+    data = qobject_from_jsonf("{'device': %s, 'action': %s, 'operation': %s}",
+                              device, action_str, is_read ? "read" : "write");
+    monitor_protocol_event(QEVENT_DISK_ERROR, data);
+    qobject_decref(data);
+}
+
 BlockInterfaceErrorAction drive_get_on_error(
     BlockDriverState *bdrv, int is_read)
 {
-    return drive_get_err_action(bdrv, is_read);
+    BlockInterfaceErrorAction action;
+
+    action = drive_get_err_action(bdrv, is_read);
+    driver_err_event(action, is_read, bdrv->device_name);
+
+    return action;
 }
 
 static void bdrv_format_print(void *opaque, const char *name)
-- 
1.6.6