From: Eric Sandeen Subject: Re: Fwd: Ext4 bug with fallocate Date: Tue, 27 Oct 2009 08:56:53 -0500 Message-ID: <4AE6FC25.3000801@redhat.com> References: <4AE67A1B.8060704@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: Fredrik Andersson Return-path: Received: from mx1.redhat.com ([209.132.183.28]:6304 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754345AbZJ0N4y (ORCPT ); Tue, 27 Oct 2009 09:56:54 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: Fredrik Andersson wrote: >> Not trying to ignore you, but trying to sort out some corruption issues that >> I'm afraid I have to rank higher than a hang for now... > > I understand. Good to know someone is thinking about it anyway :-) > >> From the traces, things are hung up on the i_data_sem; several pdflushes >> want it for read in ext4_get_blocks_wrap, and drbdmakes presumably have it >> downed for write in ext4_ext_truncate. I'm not immediately seeing the >> deadlock tonight, but then it's getting late... >> >> Is the application that's triggering this something you can share? >> > > Sorry, I can't provide source code for these applications. Ok, I understand > But drdbmake does what is described above: Preallocates a very big > chunk on disk and then > truncates it to its final length once it's done. To try to emulate, how does it write into the preallocated space; large or small IOs? Sequential streaming? mmap writes? It may not be relevant but would be nice to try to match it as closely as possible. Thanks, -Eric > Please let me know if you need more details. > > /Fredrik