Return-Path: Received: from cantor2.suse.de ([195.135.220.15]:50159 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752406Ab1CIUfX (ORCPT ); Wed, 9 Mar 2011 15:35:23 -0500 Date: Thu, 10 Mar 2011 07:35:15 +1100 From: NeilBrown To: "Assarsson, Emil" Cc: "'linux-nfs@vger.kernel.org'" Subject: Re: mountd --manage-gids supports max 100 groups? Message-ID: <20110310073515.799d1530@notabene.brown> In-Reply-To: <2BF070A7A2375D46BA1B6087F8D5DCB678B8E772B8@seldmbx01.corpusers.net> References: <2BF070A7A2375D46BA1B6087F8D5DCB678B8E772B8@seldmbx01.corpusers.net> Content-Type: text/plain; charset=US-ASCII Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Wed, 9 Mar 2011 16:20:42 +0100 "Assarsson, Emil" wrote: > Hi All, > > Running linux kernel 2.6.32 and nfs-utils 1.2.0 (Ubuntu Lucid) > > A regular user in our company usually is member of more than 300 groups. Some user even have up to 600. We want to use the --manage-gids option for mountd. However it seems to me that it is limited to about 100 groups. > > The reason seems to be that there is a hard limit for mountd but also that the /proc/net/rpc/auth.unix.gid/channel won't accept more than 1008 characters as input. > > I tried to adjust the code for mountd so that it tried to add up to 1000 groups but then I ran in to the channel problem. > > Can someone please guide me to the place where I can adjust this limit? > The limit should be 8192, not 1008. This is set in net/sunrpc/cache.c If the write is less than one page, it is handled in cache_downcall(). If it is bigger it is passed to cache_slow_downcall() which stops at 8192 (but could trivially be make to handle more). What is your evidence that '.../channel won't accept more than 1008 characters as input" ??? Thanks, NeilBrown