From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH] loop: Make explicit loop device destruction lazy Date: Sat, 29 Sep 2012 07:51:11 +0200 Message-ID: <50668C4F.8010300@kernel.dk> References: <1348812593-21344-1-git-send-email-david@fromorbit.com> <506562CE.2070500@kernel.dk> <20120928143844.GA1454@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: Dave Jones , Dave Chinner , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Return-path: Received: from casper.infradead.org ([85.118.1.10]:45796 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753696Ab2I2Fvo (ORCPT ); Sat, 29 Sep 2012 01:51:44 -0400 In-Reply-To: <20120928143844.GA1454@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 2012-09-28 16:38, Dave Jones wrote: > On Fri, Sep 28, 2012 at 10:41:50AM +0200, Jens Axboe wrote: > > > > Turns out that blkid is running simultaneously with losetup -d, and > > > so it sees an elevated reference count and returns EBUSY. But why > > > is blkid running? It's obvious, isn't it? udev has decided to try > > > and find out what is on the block device as a result of a creation > > > notification. And it is racing with mkfs, so might still be scanning > > > the device when mkfs finishes and we try to tear it down. > > > > > I hear that %^#@#! blkid behavior, it is such a pain in the neck. I > > don't know how many times I've had to explain that behaviour to people > > who run write testing with tracing, wonder wtf there are reads in the > > trace. > > Could this problem explain this bug too ? https://bugzilla.redhat.com/show_bug.cgi?id=853674 It certainly looks like it! -- Jens Axboe