Return-Path: linux-nfs-owner@vger.kernel.org Received: from bombadil.infradead.org ([198.137.202.9]:39100 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751373Ab3KRRra (ORCPT ); Mon, 18 Nov 2013 12:47:30 -0500 Date: Mon, 18 Nov 2013 09:47:29 -0800 From: Christoph Hellwig To: "J. Bruce Fields" Cc: Christoph Hellwig , Albert Fluegel , linux-nfs@vger.kernel.org Subject: Re: Bugs / Patch in nfsd Message-ID: <20131118174729.GA16577@infradead.org> References: <20131118124406.GA46678@colin.muc.de> <20131118130026.GA4153@infradead.org> <20131118170132.GD3203@fieldses.org> <20131118172315.GA20339@infradead.org> <20131118173731.GF3203@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20131118173731.GF3203@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Nov 18, 2013 at 12:37:31PM -0500, J. Bruce Fields wrote: > One problem he's seeing was RHEL5-specific, the other is the known ext4 > problem that's been discussed before. Ok, didn't know there was a RHEL bug. > (Basically, ext4 has a tradeoff between correctness, lookup performance, > and compatibility with some buggy old clients: > > 1. turn off dir_index and performance on large directories may > suffer, but it's correct and any client will be happy. > 2. turn on dir_index and return 32-bit cookies: now you get > directory loops on large directories due to random hash > collisions. > 3. turn on dir_index and return 64-bit cookies: some clients seem > to then return errors to 32-bit applications doing readdirs. > Cookies have been 64-bit since NFSv3 and 32-bit Linux clients > deal with this fine (it fakes up its own small integer offsets > to return to applications), but apparently some other clients > return errors on readdir. > > So currently we default to 3 and if people complain, tell them to turn > off dir_index and complain to their client vendor....) Or people could use a filesystem taking care of that. In addition to taking care of the directory index XFS also has other advantages like much better support to get the metadata operations to disk a lot more efficiently. ... working hard on my marketing skills..