From patchwork Wed May 31 12:45:31 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 769100 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3wd9KP4Xf6z9s78 for ; Wed, 31 May 2017 22:49:29 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751162AbdEaMtJ (ORCPT ); Wed, 31 May 2017 08:49:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60050 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751314AbdEaMpx (ORCPT ); Wed, 31 May 2017 08:45:53 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 884C94E356; Wed, 31 May 2017 12:45:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 884C94E356 Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jlayton@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 884C94E356 Received: from tleilax.poochiereds.net (ovpn-120-5.rdu2.redhat.com [10.10.120.5]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6F9EAC4517; Wed, 31 May 2017 12:45:51 +0000 (UTC) From: Jeff Layton To: Andrew Morton , Al Viro , Jan Kara , tytso@mit.edu, axboe@kernel.dk, mawilcox@microsoft.com, ross.zwisler@linux.intel.com, corbet@lwn.net Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-doc@vger.kernel.org Subject: [PATCH v5 08/17] dax: set errors in mapping when writeback fails Date: Wed, 31 May 2017 08:45:31 -0400 Message-Id: <20170531124540.8782-9-jlayton@redhat.com> In-Reply-To: <20170531124540.8782-1-jlayton@redhat.com> References: <20170531124540.8782-1-jlayton@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 31 May 2017 12:45:52 +0000 (UTC) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Jan's description for this patch is much better than mine, so I'm quoting it verbatim here: -----------------8<----------------- DAX currently doesn't set errors in the mapping when cache flushing fails in dax_writeback_mapping_range(). Since this function can get called only from fsync(2) or sync(2), this is actually as good as it can currently get since we correctly propagate the error up from dax_writeback_mapping_range() to filemap_fdatawrite() However, in the future better writeback error handling will enable us to properly report these errors on fsync(2) even if there are multiple file descriptors open against the file or if sync(2) gets called before fsync(2). So convert DAX to using standard error reporting through the mapping. -----------------8<----------------- For now, only do this when the FS_WB_ERRSEQ flag is set. The AS_EIO/AS_ENOSPC flags are not currently cleared in the older code when writeback initiation fails, only when we discover an error after waiting on writeback to complete, so we only want to do this with errseq_t based error handling to prevent seeing duplicate errors on fsync. Signed-off-by: Jeff Layton Reviewed-by: Jan Kara Reviewed-by: Christoph Hellwig Reviewed-and-Tested-by: Ross Zwisler --- fs/dax.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/fs/dax.c b/fs/dax.c index c22eaf162f95..42788d8505c7 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -856,8 +856,24 @@ int dax_writeback_mapping_range(struct address_space *mapping, ret = dax_writeback_one(bdev, dax_dev, mapping, indices[i], pvec.pages[i]); - if (ret < 0) + if (ret < 0) { + /* + * For fs' that use errseq_t based error + * tracking, we must call mapping_set_error + * here to ensure that fsync on all open fds + * get back an error. Doing this with the old + * wb error tracking infrastructure is + * problematic though, as DAX writeback is + * synchronous, and the error flags are not + * cleared when initiation fails, only when + * it fails after the write has been submitted + * to the backing store. + */ + if (mapping->host->i_sb->s_type->fs_flags & + FS_WB_ERRSEQ) + mapping_set_error(mapping, ret); goto out; + } } } out: