[Libguestfs] [PATCH v4 18/24] nbd/client: Plumb errp through nbd_receive_replies

[Vladimir Sementsov-Ogievskiy]

On 08.06.23 16:56, Eric Blake wrote:
> Instead of ignoring the low-level error just to refabricate our own
> message to pass to the caller, we can just plump the caller's errp
> down to the low level.
> 
> Signed-off-by: Eric Blake <eblake at redhat.com>
> ---
> 
> v4: new patch [Vladimir]
> ---
>   block/nbd.c | 16 ++++++++++------
>   1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/block/nbd.c b/block/nbd.c
> index 57123c17f94..c17ce935f17 100644
> --- a/block/nbd.c
> +++ b/block/nbd.c
> @@ -417,7 +417,8 @@ static void coroutine_fn GRAPH_RDLOCK nbd_reconnect_attempt(BDRVNBDState *s)
>       reconnect_delay_timer_del(s);
>   }
> 
> -static coroutine_fn int nbd_receive_replies(BDRVNBDState *s, uint64_t cookie)
> +static coroutine_fn int nbd_receive_replies(BDRVNBDState *s, uint64_t cookie,
> +                                            Error **errp)
>   {
>       int ret;
>       uint64_t ind = COOKIE_TO_INDEX(cookie), ind2;
> @@ -458,9 +459,12 @@ static coroutine_fn int nbd_receive_replies(BDRVNBDState *s, uint64_t cookie)
> 
>           /* We are under mutex and cookie is 0. We have to do the dirty work. */
>           assert(s->reply.cookie == 0);
> -        ret = nbd_receive_reply(s->bs, s->ioc, &s->reply, NULL);
> -        if (ret <= 0) {
> -            ret = ret ? ret : -EIO;
> +        ret = nbd_receive_reply(s->bs, s->ioc, &s->reply, errp);
> +        if (ret == 0) {
> +            ret = -EIO;
> +            error_setg(errp, "server dropped connection");

we also need to set errp for further negative returns in the function

> +        }
> +        if (ret < 0) {
>               nbd_channel_error(s, ret);
>               return ret;
>           }
> @@ -843,9 +847,9 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
>       }
>       *request_ret = 0;
> 
> -    ret = nbd_receive_replies(s, cookie);
> +    ret = nbd_receive_replies(s, cookie, errp);
>       if (ret < 0) {
> -        error_setg(errp, "Connection closed");
> +        error_prepend(errp, "Connection closed: ");
>           return -EIO;
>       }
>       assert(s->ioc);

-- 
Best regards,
Vladimir