From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44513C4360C for ; Wed, 2 Oct 2019 19:10:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1C73D21D82 for ; Wed, 2 Oct 2019 19:10:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729844AbfJBTK0 (ORCPT ); Wed, 2 Oct 2019 15:10:26 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35902 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729321AbfJBTIR (ORCPT ); Wed, 2 Oct 2019 15:08:17 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iFjyx-000365-MX; Wed, 02 Oct 2019 20:08:15 +0100 Received: from ben by deadeye with local (Exim 4.92.1) (envelope-from ) id 1iFjyp-0003eu-9A; Wed, 02 Oct 2019 20:08:07 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Naohiro Aota" , "David Sterba" , "Filipe Manana" Date: Wed, 02 Oct 2019 20:06:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 63/87] btrfs: start readahead also in seed devices In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.75-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Naohiro Aota commit c4e0540d0ad49c8ceab06cceed1de27c4fe29f6e upstream. Currently, btrfs does not consult seed devices to start readahead. As a result, if readahead zone is added to the seed devices, btrfs_reada_wait() indefinitely wait for the reada_ctl to finish. You can reproduce the hung by modifying btrfs/163 to have larger initial file size (e.g. xfs_io pwrite 4M instead of current 256K). Fixes: 7414a03fbf9e ("btrfs: initial readahead code and prototypes") Reviewed-by: Filipe Manana Signed-off-by: Naohiro Aota Signed-off-by: David Sterba --- fs/btrfs/reada.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/fs/btrfs/reada.c +++ b/fs/btrfs/reada.c @@ -764,6 +764,7 @@ static void __reada_start_machine(struct u64 total = 0; int i; +again: do { enqueued = 0; mutex_lock(&fs_devices->device_list_mutex); @@ -776,6 +777,10 @@ static void __reada_start_machine(struct mutex_unlock(&fs_devices->device_list_mutex); total += enqueued; } while (enqueued && total < 10000); + if (fs_devices->seed) { + fs_devices = fs_devices->seed; + goto again; + } if (enqueued == 0) return;