Re: [Qemu-devel] [PATCH 1/3] io: Implement QIO_CHANNEL_ERR_BROKEN

["Daniel P. Berrangé" <berrange@redhat.com>]

On Thu, May 31, 2018 at 09:45:59AM +0200, Sergio Lopez wrote:
> QIO_CHANNEL_ERR_BROKEN is used to identify a potentially unrecoverable
> error in the channel, like EPIPE.
> ---
>  include/io/channel.h | 1 +
>  io/channel-file.c    | 3 +++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/include/io/channel.h b/include/io/channel.h
> index e8cdadb..bbe45f6 100644
> --- a/include/io/channel.h
> +++ b/include/io/channel.h
> @@ -38,6 +38,7 @@ typedef struct QIOChannel QIOChannel;
>  typedef struct QIOChannelClass QIOChannelClass;
>  
>  #define QIO_CHANNEL_ERR_BLOCK -2
> +#define QIO_CHANNEL_ERR_BROKEN -3
>  
>  typedef enum QIOChannelFeature QIOChannelFeature;
>  
> diff --git a/io/channel-file.c b/io/channel-file.c
> index db948ab..a990f67 100644
> --- a/io/channel-file.c
> +++ b/io/channel-file.c
> @@ -124,6 +124,9 @@ static ssize_t qio_channel_file_writev(QIOChannel *ioc,
>          if (errno == EAGAIN) {
>              return QIO_CHANNEL_ERR_BLOCK;
>          }
> +        if (errno == EPIPE) {
> +            return QIO_CHANNEL_ERR_BROKEN;
> +        }
>          if (errno == EINTR) {
>              goto retry;
>          }

I don't see a compelling reason to add this.  EAGAIN needs special
handling because we do not wish to set the "Error **errp" object.
EPIPE can be just handled by callers in the same way as any other
errno value, by closing the connection.

Regards,
Daniel
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