Re: [Qemu-devel] [PATCH] qmp: add BLOCK_MEDIUM_EJECT event

[Paolo Bonzini <pbonzini@redhat.com>]

On 01/24/2012 07:16 PM, Luiz Capitulino wrote:
> @@ -237,6 +238,17 @@ static bool do_check_io_limits(BlockIOLimit *io_limits)
>      return true;
>  }
>
> +static void on_medium_eject(BlockDriverState *bs, int is_ejected)
> +{
> +    QObject *data;
> +
> +    data = qobject_from_jsonf("{ 'device': %s, 'ejected': %i }",
> +                              bdrv_get_device_name(bs), is_ejected);
> +    monitor_protocol_event(QEVENT_BLOCK_MEDIUM_EJECT, data);
> +
> +    qobject_decref(data);
> +}
> +
>  DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
>  {
>      const char *buf;
> @@ -503,6 +515,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
>      QTAILQ_INSERT_TAIL(&drives, dinfo, next);
>
>      bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
> +    bdrv_dev_set_medium_eject_notify(dinfo->bdrv, on_medium_eject);
>
>      /* disk I/O throttling */
>      bdrv_set_io_limits(dinfo->bdrv, &io_limits);

block.c/blockdev.c separation is nice, but do we really need a function 
pointer?  Also, we're already emitting the BLOCK_IO_ERROR event in 
block.c; is that another place to cleanup, or is this overkill and we 
can just put bdrv_dev_medium_eject_notify in block.c?

> diff --git a/hw/ide/atapi.c b/hw/ide/atapi.c
> index 0adb27b..4b4bc61 100644
> --- a/hw/ide/atapi.c
> +++ b/hw/ide/atapi.c
> @@ -885,6 +885,7 @@ static void cmd_start_stop_unit(IDEState*s, uint8_t*  buf)
>           }
>           bdrv_eject(s->bs, !start);
>           s->tray_open = !start;
> +        bdrv_dev_medium_eject_notify(s->bs, !start);
>       }
>
>       ide_atapi_cmd_ok(s);
> diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
> index 5d8bf53..35e55f4 100644
> --- a/hw/scsi-disk.c
> +++ b/hw/scsi-disk.c
> @@ -1061,6 +1061,7 @@ static int scsi_disk_emulate_start_stop(SCSIDiskReq *r)
>           }
>           bdrv_eject(s->qdev.conf.bs, !start);
>           s->tray_open = !start;
> +        bdrv_dev_medium_eject_notify(s->qdev.conf.bs, !start);
>       }
>       return 0;
>   }

Can you do the call directly in bdrv_eject (but I would skip 
bdrv_close)?  The only other place where bdrv_eject is called is from 
block/raw.c's raw_eject, but I think you should only emit the event if 
bs->device_name[0] (otherwise the event is quite useless) and bs->file 
will fail the test.

Paolo