From: Eric Sandeen Subject: Re: Fwd: Ext4 bug with fallocate Date: Mon, 26 Oct 2009 23:42:03 -0500 Message-ID: <4AE67A1B.8060704@redhat.com> References: 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]:34504 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751337AbZJ0Ema (ORCPT ); Tue, 27 Oct 2009 00:42:30 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: Fredrik Andersson wrote: > Hi, I'd like to report what I'm fairly certain is an ext4 bug. I hope > this is the right place to do so. > > My program creates a big file (around 30 GB) with posix_fallocate (to > utilize extents), fills it with data and uses ftruncate to crop it to > its final size (usually somewhere between 20 and 25 GB). > The problem is that in around 5% of the cases, the program locks up > completely in a syscall. The process can thus not be killed even with > kill -9, and a reboot is all that will do. 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... 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? Thanks, -Eric