From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f170.google.com ([209.85.220.170]:34658 "EHLO mail-qk0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1948813AbdEZXBs (ORCPT ); Fri, 26 May 2017 19:01:48 -0400 Received: by mail-qk0-f170.google.com with SMTP id k74so17958774qke.1 for ; Fri, 26 May 2017 16:01:48 -0700 (PDT) Message-ID: <1495839704.10167.3.camel@redhat.com> Subject: Re: [PATCH] dax: set errors in mapping when writeback fails From: Jeff Layton To: Ross Zwisler Cc: Matthew Wilcox , linux-fsdevel@vger.kernel.org Date: Fri, 26 May 2017 19:01:44 -0400 In-Reply-To: <20170526203146.GA3778@linux.intel.com> References: <20170525104746.8032-1-jlayton@redhat.com> <20170526203146.GA3778@linux.intel.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, 2017-05-26 at 14:31 -0600, Ross Zwisler wrote: > On Thu, May 25, 2017 at 06:47:46AM -0400, Jeff Layton wrote: > > Jan's description for this patch is much better than mine, so I'm > > quoting it verbatim here: > > > > 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. > > > > Signed-off-by: Jeff Layton > > Reviewed-by: Jan Kara > > Reviewed-by: Christoph Hellwig > > Reviewed-and-Tested-by: Ross Zwisler > > Is this still part of a larger series, or are you trying to submit it on its > own? I was trying to submit it on its own. Trying to get a series merged that sprawls over the tree like this is proving difficult, so I was hoping to get maintainers to pick up individual patches for their subsystems. > On it's own this patch still suffers from the issue I reported here: > > https://lkml.org/lkml/2017/3/6/976 > My bad. I remember seeing you mail this and then let it slip through the cracks. Let's see, you said: > I think maybe the missing piece is that our normal DAX fsync call stack > doesn't include a call to filemap_check_errors() if we return -EIO. I think the actual problem is in filemap_write_and_wait_range. When there is an error from __filemap_fdatawrite_range, we probably ought to go ahead and clear the AS_EIO/AS_ENOSPC flags as well even though we're not waiting on writeback. I think I had a patch to do that in an earlier iteration of this series, but I dropped it when I started pursuing the errseq_t based error tracking. Now that we're going to have to do this in a more piecemeal way, it may be worth resurrecting that patch as an interim step before merging this one. I'll see if I can dust that patch off after the holiday weekend. Thanks, -- Jeff Layton