From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ipmail06.adl6.internode.on.net ([150.101.137.145]:36485 "EHLO ipmail06.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751515AbbKHVwQ (ORCPT ); Sun, 8 Nov 2015 16:52:16 -0500 Date: Mon, 9 Nov 2015 08:51:57 +1100 From: Dave Chinner Subject: Re: [PATCH] btrfs: test quota disable during quota rescan Message-ID: <20151108215157.GA14311@dastard> References: <1446835221-11905-1-git-send-email-jmaggard@netgear.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: fstests-owner@vger.kernel.org To: Filipe Manana Cc: Justin Maggard , fstests@vger.kernel.org, "linux-btrfs@vger.kernel.org" , Justin Maggard List-ID: On Sat, Nov 07, 2015 at 03:08:01PM +0000, Filipe Manana wrote: > On Fri, Nov 6, 2015 at 6:40 PM, Justin Maggard wrote: > > This test case tests if we are able to disable quotas on a filesystem > > while a quota rescan is running. Up to now (4.3) this would result > > in a kernel NULL pointer dereference. > > > > Fixed by patch (btrfs: qgroup: fix quota disable during rescan). > > > > Signed-off-by: Justin Maggard > Reviewed-by: Filipe Manana > > Looks good and it triggers the bug without the btrfs kernel fix. > > A side note, and if you would like you could do as a separate patch > imho, is to speedup creating the files by using multiple > jobs/processes (as we do in generic/038 for example) - the test takes > 150 seconds on a debug kernel here, about 130 seconds were spent > creating the files. Same observation applies to your previous test > case as well. Given how many people get such a basic operation "wrong", we need a helper function for efficiently creating lots of empty files in a filesystem. Note that we already have _populate_fs(), but it's not very efficient when it comes to empty files, nor does it use concurrency. It seems to me that fixing this function and then using it everywhere would be the best approach. Perhaps even doing something like making fs_mark use deep directory structures, and just calling it instead to populate the filesystem? Cheers, Dave. -- Dave Chinner david@fromorbit.com