From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:21495 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753057AbaDGQMO (ORCPT ); Mon, 7 Apr 2014 12:12:14 -0400 Message-ID: <5342CE0C.3070707@fb.com> Date: Mon, 7 Apr 2014 12:10:52 -0400 From: Josef Bacik MIME-Version: 1.0 To: Marc MERLIN , Subject: Re: btrfs on 3.14rc5 stuck on "btrfs_tree_read_lock sync" References: <20140407160506.GG10789@merlins.org> In-Reply-To: <20140407160506.GG10789@merlins.org> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 04/07/2014 12:05 PM, Marc MERLIN wrote: > I was debugging my why backup failed to run, and eventually found it was > stuck on sync: > 14080 18:18 btrfs_tree_read_lock sync > > This was hung for hours on this lock. > > Strangely, it looks like taking my sysrq-w hung the machine pretty hard for > close to 30sec, but this seems to have unhung sync and in the end btrfs send > completed after that. > > Sysqrq-w is here: > https://urldefense.proofpoint.com/v1/url?u=http://marc.merlins.org/tmp/sysrq-btrfs-sync-hang.txt&k=ZVNjlDMF0FElm4dQtryO4A%3D%3D%0A&r=cKCbChRKsMpTX8ybrSkonQ%3D%3D%0A&m=IHXWC1Chbc0jEiUWu1v4Va9NOphtjPbjYp6yVMdUmXM%3D%0A&s=bd787a3422e9ff0972d2d09de7d424f56589aadc9d6db33e19fc44886dce604f Try Chris's integration branch in a few hours and see if that fixes it. Thanks, Josef