Libguestfs - Nov 2018 - [nbdkit PATCH] connections: Be less noisy when client sends NBD_OPT_ABORT

At least 'nbd-client -l localhost' is a good demonstration of a
client that legitimately sends NBD_OPT_ABORT - it exists only
to enumerate the exports advertised by the server, rather than
intending to connect to any of those exports.  As such, we should
downgrade the message for a client telling us it is going away
to the same status as our debug message for NBD_CMD_DISC, given
that the two have the same effect at different points in the
protocol.  This stops nbdkit from spamming stderr with

nbdkit: file[1]: error: client sent NBD_OPT_ABORT to abort the connection

messages due to a client that doesn't want to connect after all.

Signed-off-by: Eric Blake <eblake@redhat.com>
---

Found while implementing a similar 'qemu-nbd --list' that is
nicer than nbd-client's version ;)

 src/connections.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/connections.c b/src/connections.c
index e1ffeff..1b40e46 100644
--- a/src/connections.c
+++ b/src/connections.c
@@ -705,7 +705,7 @@ _negotiate_handshake_newstyle_options (struct connection
*conn)
     case NBD_OPT_ABORT:
       if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
         return -1;
-      nbdkit_error ("client sent NBD_OPT_ABORT to abort the
connection");
+      debug ("client sent NBD_OPT_ABORT to abort the connection");
       return -1;

     case NBD_OPT_LIST:
-- 
2.17.2

On Wed, Nov 28, 2018 at 01:39:11PM -0600, Eric Blake
wrote:
> At least 'nbd-client -l localhost' is a good demonstration of a
> client that legitimately sends NBD_OPT_ABORT - it exists only
> to enumerate the exports advertised by the server, rather than
> intending to connect to any of those exports.  As such, we should
> downgrade the message for a client telling us it is going away
> to the same status as our debug message for NBD_CMD_DISC, given
> that the two have the same effect at different points in the
> protocol.  This stops nbdkit from spamming stderr with
> 
> nbdkit: file[1]: error: client sent NBD_OPT_ABORT to abort the connection
> 
> messages due to a client that doesn't want to connect after all.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
> 
> Found while implementing a similar 'qemu-nbd --list' that is
> nicer than nbd-client's version ;)
> 
>  src/connections.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/connections.c b/src/connections.c
> index e1ffeff..1b40e46 100644
> --- a/src/connections.c
> +++ b/src/connections.c
> @@ -705,7 +705,7 @@ _negotiate_handshake_newstyle_options (struct
connection *conn)
>      case NBD_OPT_ABORT:
>        if (send_newstyle_option_reply (conn, option, NBD_REP_ACK) == -1)
>          return -1;
> -      nbdkit_error ("client sent NBD_OPT_ABORT to abort the
connection");
> +      debug ("client sent NBD_OPT_ABORT to abort the
connection");
>        return -1;
> 
>      case NBD_OPT_LIST:
Yup, that's not an error :-)

ACK.

Rich.

-- 
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