From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:60324 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031974AbdADUMb (ORCPT ); Wed, 4 Jan 2017 15:12:31 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bart Van Assche , Mike Snitzer Subject: [PATCH 4.9 59/83] dm table: fix all_blk_mq inconsistency when an empty table is loaded Date: Wed, 4 Jan 2017 21:06:51 +0100 Message-Id: <20170104200448.937850545@linuxfoundation.org> In-Reply-To: <20170104200446.541604386@linuxfoundation.org> References: <20170104200446.541604386@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Snitzer commit 6936c12cf809850180b24947271b8f068fdb15e9 upstream. An earlier DM multipath table could have been build ontop of underlying devices that were all using blk-mq. In that case, if that active multipath table is replaced with an empty DM multipath table (that reflects all paths have failed) then it is important that the 'all_blk_mq' state of the active table is transfered to the new empty DM table. Otherwise dm-rq.c:dm_old_prep_tio() will incorrectly clone a request that isn't needed by the DM multipath target when it is to issue IO to an underlying blk-mq device. Fixes: e83068a5 ("dm mpath: add optional "queue_mode" feature") Reported-by: Bart Van Assche Tested-by: Bart Van Assche Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-table.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -924,12 +924,6 @@ static int dm_table_determine_type(struc BUG_ON(!request_based); /* No targets in this table */ - if (list_empty(devices) && __table_type_request_based(live_md_type)) { - /* inherit live MD type */ - t->type = live_md_type; - return 0; - } - /* * The only way to establish DM_TYPE_MQ_REQUEST_BASED is by * having a compatible target use dm_table_set_type. @@ -948,6 +942,19 @@ verify_rq_based: return -EINVAL; } + if (list_empty(devices)) { + int srcu_idx; + struct dm_table *live_table = dm_get_live_table(t->md, &srcu_idx); + + /* inherit live table's type and all_blk_mq */ + if (live_table) { + t->type = live_table->type; + t->all_blk_mq = live_table->all_blk_mq; + } + dm_put_live_table(t->md, srcu_idx); + return 0; + } + /* Non-request-stackable devices can't be used for request-based dm */ list_for_each_entry(dd, devices, list) { struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);