From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751479AbbDHGYO (ORCPT ); Wed, 8 Apr 2015 02:24:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57798 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751202AbbDHGYL (ORCPT ); Wed, 8 Apr 2015 02:24:11 -0400 From: Jarod Wilson To: linux-kernel@vger.kernel.org Cc: Jarod Wilson , Christoph Hellwig , Jens Axboe , Tejun Heo , Alexander Viro , Markus Pargmann , Stefan Weinhuber , Stefan Haberland , Sebastian Ott , Fabian Frederick , Ming Lei , David Herrmann , Mike Galbraith , Andrew Morton , Peter Zijlstra , nbd-general@lists.sourceforge.net, linux-s390@vger.kernel.org Subject: [PATCH 0/7] block: reread partitions improvements Date: Wed, 8 Apr 2015 02:23:39 -0400 Message-Id: <1428474226-27386-1-git-send-email-jarod@redhat.com> In-Reply-To: <1428218688-4092-1-git-send-email-ming.lei@canonical.com> References: <1428218688-4092-1-git-send-email-ming.lei@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For loop, the root cause is one ABBA and one AA lock dependency issue, and the two are fixed by patch 2 and patch 3 each. Another reason is from the trylock in blkdev_reread_part(), which may cause partition scanning failure too sometimes when another task is holding the bd_mutex. In the discussion[1], both Tejun and Christoph suggests to replace the trylock with mutex_lock in blkdev_reread_part(), also Christoph suggests to export blkdev_reread_part. Following the discussion, this patchset exports blkdev_reread_part(), and introduces lockless __blkdev_reread_part() for fixing loop's AA lock issue. Then ioctl_by_bdev(BLKRRPART) in loop, nbd and dasd is replaced with blkdev_reread_part(). In the last patch, trylock in blkdev_reread_part() is replaced with mutex_lock, and some analysis is provided about the conversion. This is a slightly reworked set from what Ming sent a few days ago, based on Christoph's feedback. I've tested this out quite succesfully in the scenario that prompted my first patch as well. [1], https://lkml.org/lkml/2015/1/26/137 [2], https://lkml.org/lkml/2015/3/31/888 Jarod Wilson (3): block: export blkdev_reread_part() and __blkdev_reread_part() block: loop: fix another reread part failure s390/block/dasd: remove obsolete while -EBUSY loop Ming Lei (4): block: loop: don't hold lo_ctl_mutex in lo_open block: nbd: convert to blkdev_reread_part() block: dasd_genhd: convert to blkdev_reread_part block: replace trylock with mutex_lock in blkdev_reread_part() block/ioctl.c | 34 +++++++++++++++++++---- drivers/block/loop.c | 60 ++++++++++++++++++++++++++++++++++------- drivers/block/loop.h | 1 + drivers/block/nbd.c | 2 +- drivers/s390/block/dasd_genhd.c | 22 +++++---------- include/linux/fs.h | 3 +++ 6 files changed, 90 insertions(+), 32 deletions(-) CC: Christoph Hellwig CC: Jens Axboe CC: Tejun Heo CC: Alexander Viro CC: Markus Pargmann CC: Stefan Weinhuber CC: Stefan Haberland CC: Sebastian Ott CC: Fabian Frederick CC: Ming Lei CC: David Herrmann CC: Mike Galbraith CC: Andrew Morton CC: Peter Zijlstra CC: nbd-general@lists.sourceforge.net CC: linux-s390@vger.kernel.org -- 1.8.3.1