From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bernd Schubert Subject: Re: infinite getdents64 loop Date: Tue, 31 May 2011 12:18:11 +0200 Message-ID: <4DE4C063.9060100@itwm.fraunhofer.de> References: <201105281502.32719.sweet_f_a@gmx.de> <201105301137.02061.sweet_f_a@gmx.de> <1306767521.5971.2.camel@lade.trondhjem.org> <201105311147.24939.sweet_f_a@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Return-path: Received: from mailgw1.uni-kl.de ([131.246.120.220]:59965 "EHLO mailgw1.uni-kl.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754157Ab1EaKdZ (ORCPT ); Tue, 31 May 2011 06:33:25 -0400 In-Reply-To: <201105311147.24939.sweet_f_a@gmx.de> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 05/31/2011 11:47 AM, R=C3=BCdiger Meier wrote: > On Monday 30 May 2011, Trond Myklebust wrote: >> On Mon, 2011-05-30 at 11:37 +0200, Ruediger Meier wrote: >>> >>> Does this mean ext4 generally does not work with for nfs? >> >> ext2/3/4 are all known to have this problem when you switch on the >> hashed b-tree directories. Typically, a directory with a million >> entries will have several tens of cookie collisions. > > Ok, like Jeff mentioned in the other reply disabling dir_index solves > it. > > I wish I had seen this documented somewhere before switching from xfs= to > ext4 but it's not easy to find something about these ext4/nfs probs > without knowing the details already. > Ext4 being default file system on many distros made me feel safe. Well, this is hardly acceptable and we really need to find a solution. = I=20 think any parallel filesystem and fuse, etc will have problems with tha= t. Out of interest, did anyone ever benchmark if dirindex provides any=20 advantages to readdir? And did those benchmarks include the=20 disadvantages of the present implementation (non-linear inode numbers=20 from readdir, so disk seeks on stat() (e.g. from 'ls -l') or 'rm -fr $dir')? I see those options to solve the ext3/ext4 seek problem: 1) Break 32bit applications on 64 bit kernels 2) Update the vfs to tell the underlying functions to tell them if=20 lseek() was called from 64bit or 32bit userspace 3) Disable dirindexing for readdirs Thanks, Bernd -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html