From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751231AbdEaVhS (ORCPT ); Wed, 31 May 2017 17:37:18 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:54806 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbdEaVhQ (ORCPT ); Wed, 31 May 2017 17:37:16 -0400 Date: Wed, 31 May 2017 14:37:13 -0700 From: Andrew Morton To: Jeff Layton Cc: Al Viro , Jan Kara , tytso@mit.edu, axboe@kernel.dk, mawilcox@microsoft.com, ross.zwisler@linux.intel.com, corbet@lwn.net, 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: Re: [PATCH v5 00/17] fs: introduce new writeback error reporting and convert ext2 and ext4 to use it Message-Id: <20170531143713.95796a8bce699d263b764763@linux-foundation.org> In-Reply-To: <1496266309.2984.13.camel@redhat.com> References: <20170531124540.8782-1-jlayton@redhat.com> <20170531132728.2e60bd607bd4174739b6b661@linux-foundation.org> <1496266309.2984.13.camel@redhat.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 31 May 2017 17:31:49 -0400 Jeff Layton wrote: > On Wed, 2017-05-31 at 13:27 -0700, Andrew Morton wrote: > > On Wed, 31 May 2017 08:45:23 -0400 Jeff Layton wrote: > > > > > This is v5 of the patchset to improve how we're tracking and reporting > > > errors that occur during pagecache writeback. > > > > I'm curious to know how you've been testing this? > > > Is that testing > > strong enough for us to be confident that all nature of I/O errors > > will be reported to userspace? > > > > That's a tall order. This is a difficult thing to test as these sorts of > errors are pretty rare by nature. > > I have an xfstest that I posted just after this set that demonstrates > that it works correctly, at least on ext2/3/4 when run by the ext4 > driver (ext2 legacy driver reports too many errors currently). I had > btrfs and xfs working on that test too in an earlier incarnation of this > set, so I think we can fix this in them as well without too much > difficulty. > > I'm happy to run other tests if someone wants to suggest them. > > Now, all that said, I don't think this will make things any worse than > they are today as far as reporting errors properly to userland goes. > It's rather easy for an incidental synchronous writeback request from an > internal caller to clear the AS_* flags today. This will at least ensure > that we're reporting errors since a well-defined point in time when you > call fsync. Were you using error injection of some form? If so, how was that all set up?