From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756832AbZIPNnq (ORCPT ); Wed, 16 Sep 2009 09:43:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755910AbZIPNnp (ORCPT ); Wed, 16 Sep 2009 09:43:45 -0400 Received: from cantor2.suse.de ([195.135.220.15]:44373 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752199AbZIPNno (ORCPT ); Wed, 16 Sep 2009 09:43:44 -0400 Date: Wed, 16 Sep 2009 15:43:46 +0200 From: Jan Kara To: Jens Axboe Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, chris.mason@oracle.com, hch@infradead.org, tytso@mit.edu, akpm@linux-foundation.org, jack@suse.cz, trond.myklebust@fys.uio.no Subject: Re: [PATCH 10/16] writeback: splice dirty inode entries to default bdi on bdi_destroy() Message-ID: <20090916134346.GM26030@duck.suse.cz> References: <1253107494-20160-1-git-send-email-jens.axboe@oracle.com> <1253107494-20160-11-git-send-email-jens.axboe@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1253107494-20160-11-git-send-email-jens.axboe@oracle.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 16-09-09 15:24:48, Jens Axboe wrote: > We cannot safely ensure that the inodes are all gone at this point > in time, and we must not destroy this bdi with inodes having off it. > So just splice our entries to the default bdi since that one will > always persist. I'd at least add a comment like "XXX: This is probably a bug but let's workaround it for now." And either remove the code or update the comment when this gets resolved. Honza > > Signed-off-by: Jens Axboe > --- > mm/backing-dev.c | 14 +++++++++++++- > 1 files changed, 13 insertions(+), 1 deletions(-) > > diff --git a/mm/backing-dev.c b/mm/backing-dev.c > index fd93566..3d3accb 100644 > --- a/mm/backing-dev.c > +++ b/mm/backing-dev.c > @@ -668,7 +668,19 @@ void bdi_destroy(struct backing_dev_info *bdi) > { > int i; > > - WARN_ON(bdi_has_dirty_io(bdi)); > + /* > + * Splice our entries to the default_backing_dev_info, if this > + * bdi disappears > + */ > + if (bdi_has_dirty_io(bdi)) { > + struct bdi_writeback *dst = &default_backing_dev_info.wb; > + > + spin_lock(&inode_lock); > + list_splice(&bdi->wb.b_dirty, &dst->b_dirty); > + list_splice(&bdi->wb.b_io, &dst->b_io); > + list_splice(&bdi->wb.b_more_io, &dst->b_more_io); > + spin_unlock(&inode_lock); > + } > > bdi_unregister(bdi); > > -- > 1.6.4.1.207.g68ea > -- Jan Kara SUSE Labs, CR