From patchwork Tue May 2 15:03:45 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 9708231 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 04C706021C for ; Tue, 2 May 2017 15:04:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EB0C520881 for ; Tue, 2 May 2017 15:04:43 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DFEB12847F; Tue, 2 May 2017 15:04:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7165A20881 for ; Tue, 2 May 2017 15:04:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751443AbdEBPEF (ORCPT ); Tue, 2 May 2017 11:04:05 -0400 Received: from mx2.suse.de ([195.135.220.15]:38830 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751343AbdEBPEB (ORCPT ); Tue, 2 May 2017 11:04:01 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id A6A7CAAF2; Tue, 2 May 2017 15:03:59 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 4026B1E34D1; Tue, 2 May 2017 17:03:58 +0200 (CEST) From: Jan Kara To: Cc: Christoph Hellwig , Jan Kara , linux-ext4@vger.kernel.org, "Theodore Ts'o" Subject: [PATCH 1/7] ext4: Mark superblock writes synchronous for nobarrier mounts Date: Tue, 2 May 2017 17:03:45 +0200 Message-Id: <20170502150351.29452-2-jack@suse.cz> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170502150351.29452-1-jack@suse.cz> References: <20170502150351.29452-1-jack@suse.cz> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Commit b685d3d65ac7 "block: treat REQ_FUA and REQ_PREFLUSH as synchronous" removed REQ_SYNC flag from WRITE_FUA implementation. generic_make_request_checks() however strips REQ_FUA flag from a bio when the storage doesn't report volatile write cache and thus write effectively becomes asynchronous which can lead to performance regressions. This affects superblock writes for ext4. Fix the problem by marking superblock writes always as synchronous. Fixes: b685d3d65ac791406e0dfd8779cc9b3707fea5a3 CC: linux-ext4@vger.kernel.org CC: "Theodore Ts'o" Signed-off-by: Jan Kara --- fs/ext4/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index a9448db1cf7e..f902852ac13e 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4629,7 +4629,7 @@ static int ext4_commit_super(struct super_block *sb, int sync) if (sync) { unlock_buffer(sbh); error = __sync_dirty_buffer(sbh, - test_opt(sb, BARRIER) ? REQ_FUA : REQ_SYNC); + REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0)); if (error) return error;