From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:35640 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726443AbeJYHls (ORCPT ); Thu, 25 Oct 2018 03:41:48 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 28D3E81DFE for ; Wed, 24 Oct 2018 23:11:47 +0000 (UTC) Received: from [IPv6:::1] (ovpn04.gateway.prod.ext.phx2.redhat.com [10.5.9.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EDE175D9C8 for ; Wed, 24 Oct 2018 23:11:46 +0000 (UTC) From: Eric Sandeen Subject: [PATCH] xfs_repair: kick processing thread if ra_count is at limit Message-ID: <6e32c568-731b-4e19-5e54-5e44aa129f37@redhat.com> Date: Wed, 24 Oct 2018 18:11:46 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: linux-xfs Zorro hit an xfs_repair hang on a 500T filesystem where all the prefetch threads were sleeping and nothing progressed. The problem is that if every buffer we tried to read ahead in phase6 was already up to date, pf_start_io_workers has no effect; there is no io to do, and the sem_wait in pf_queuing_worker waits forever. Kick the processing thread to avoid this situation. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201173 Signed-off-by: Eric Sandeen --- My brains started leaking out debugging this, but it works, and it seems harmless. :D Happy to have review from anyone who groks the prefetch thread management better than I do... diff --git a/repair/prefetch.c b/repair/prefetch.c index 9571b24..1de0e2f 100644 --- a/repair/prefetch.c +++ b/repair/prefetch.c @@ -768,8 +768,12 @@ pf_queuing_worker( * might get stuck on a buffer that has been locked * and added to the I/O queue but is waiting for * the thread to be woken. + * Start processing as well, in case everything so + * far was already prefetched and the queue is empty. */ + pf_start_io_workers(args); + pf_start_processing(args); sem_wait(&args->ra_count); }