Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     Olaf Hering <olaf@aepfle.de>
Cc:     "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Sasha Levin <sashal@kernel.org>,
        "open list\:Hyper-V CORE AND DRIVERS" <linux-hyperv@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1] tools/hv: async name resolution in kvp_daemon
In-Reply-To: <20191107152059.6cae8f30.olaf@aepfle.de>
References: <20191024144943.26199-1-olaf@aepfle.de> <874kzfbybk.fsf@vitty.brq.redhat.com> <20191107144850.37587edb.olaf@aepfle.de> <87zhh7ai26.fsf@vitty.brq.redhat.com> <20191107152059.6cae8f30.olaf@aepfle.de>
Date:   Thu, 07 Nov 2019 15:44:27 +0100
Message-ID: <87wocbagqc.fsf@vitty.brq.redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=WINDOWS-1252
Content-Transfer-Encoding: quoted-printable
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Olaf Hering <olaf@aepfle.de> writes:

> Am Thu, 07 Nov 2019 15:15:45 +0100
> schrieb Vitaly Kuznetsov <vkuznets@redhat.com>:
>
>> Looping forever with a permanent error is pretty unusual...
>
> That might be true, but how would you detect a permanent error?
> Just because the DNS server is gone for one hour does not mean it will be=
 gone forever.

'man 3 getaddrinfo' lists the following:

       EAI_ADDRFAMILY
       EAI_AGAIN
       EAI_BADFLAGS
       EAI_FAIL
       EAI_FAMILY
       EAI_MEMORY
       EAI_NODATA
       EAI_NONAME
       EAI_SERVICE
       EAI_SOCKTYPE
       EAI_SYSTEM

I *think* what you're aiming at is EAI_AGAIN and EAI_FAIL, the rest
should probably terminate the resolver thread (e.g. AF_INET is
unsupported or something like that).

--=20
Vitaly