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

[Kevin Wolf <kwolf@redhat.com>]

Am 01.02.2010 19:07, schrieb Luiz Capitulino:
> 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";

This is wrong. If it's BLOCK_ERR_STOP_ENOSPC, the action taken depends
on the error code. It might as well be a "report" instead of "stop" if
it was an EIO, for example.

But the problem is probably going to go away when you stop abusing a
getter function and add some calls that are explicitly made for your
requirements.

Kevin