Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:52730 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932119AbbLGREQ (ORCPT ); Mon, 7 Dec 2015 12:04:16 -0500 Date: Mon, 7 Dec 2015 12:04:15 -0500 From: Scott Mayhew To: Chuck Lever Cc: Steve Dickson , Linux NFS Mailing List Subject: Re: [nfs-utils PATCH] statd: make statd_canonical_name emit a warning if the presentation address maps to an empty hostname Message-ID: <20151207170414.GI4405@tonberry.usersys.redhat.com> References: <1449506523-21897-1-git-send-email-smayhew@redhat.com> <9457C117-431E-40ED-9A3A-5EBE866C7BAF@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <9457C117-431E-40ED-9A3A-5EBE866C7BAF@oracle.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, 07 Dec 2015, Chuck Lever wrote: > > > On Dec 7, 2015, at 11:42 AM, Scott Mayhew wrote: > > > > Certain name resolution misconfigurations (for example, a hosts file > > entry with an ip address but no hostnames) can cause get_nameinfo() to > > return an empty string in buf, which will lead to this cryptic failure: > > > > Dec 7 09:37:44 hostname rpc.statd[8024]: Failed to insert: creating > > /var/lib/nfs/statd/sm/: Is a directory > > Dec 7 09:37:44 hostname rpc.statd[8024]: STAT_FAIL to > > hostname.example.com for SM_MON of 192.168.1.2 > > Dec 7 09:37:44 hostname kernel: lockd: cannot monitor 192.168.1.2 > > > > It's better in that case to just go ahead and use the presentation > > address and log a more helpful warning: > > Doesn???t this change wire behavior? Some peers do not appreciate > receiving a presentation address, which is why statd/sm_notify > avoid sending them. I was just trying to keep it in line with the behavior you had added in e22f5a9c (statd: statd fails to monitor if no reverse mapping of mon_name exists). As it stands now, if get_nameinfo() fails outright then the presentation address is used and we're able to monitor the peer just fine... but get_nameinfo() succeeds and returns an empty hostname then we ultimately wind up failing to monitor the peer. > > I think it would be better to _skip_ this address and print the > warning? IMO. > That's actually what I had at first and if you think that's better then that's fine too. The rest of the errors would still get logged then, but at least the reason would be a little more apparent. -Scott > > > Dec 7 10:24:52 hostname rpc.statd[14224]: get_nameinfo returned empty > > hostname for 10.10.183.219. Fix your name resolution! > > > > Signed-off-by: Scott Mayhew > > --- > > utils/statd/hostname.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/utils/statd/hostname.c b/utils/statd/hostname.c > > index c61087c..86d11ca 100644 > > --- a/utils/statd/hostname.c > > +++ b/utils/statd/hostname.c > > @@ -211,6 +211,12 @@ statd_canonical_name(const char *hostname) > > /* OK to use presentation address, > > * if no reverse map exists */ > > return strdup(hostname); > > + else if (buf[0] == '\0') { > > + xlog_warn("get_nameinfo returned empty hostname for " > > + "%s. Fix your name resolution!", > > + hostname); > > + return strdup(hostname); > > + } > > return strdup(buf); > > } > > > > -- > > 2.4.3 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > Chuck Lever > > > >