Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753738AbdHQWpg (ORCPT ); Thu, 17 Aug 2017 18:45:36 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:32876 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753147AbdHQWpf (ORCPT ); Thu, 17 Aug 2017 18:45:35 -0400 From: Annie Li To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: roger.pau@citrix.com, konrad.wilk@oracle.com, annie.li@oracle.com Subject: [PATCH 1/1] xen-blkback: stop blkback thread of every queue in xen_blkif_disconnect Date: Thu, 17 Aug 2017 18:43:46 -0400 Message-Id: <1503009826-3363-1-git-send-email-annie.li@oracle.com> X-Mailer: git-send-email 1.9.3 X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2140 Lines: 56 If there is inflight I/O in any non-last queue, blkback returns -EBUSY directly, and never stops thread of remaining queue and processs them. When removing vbd device with lots of disk I/O load, some queues with inflight I/O still have blkback thread running even though the corresponding vbd device or guest is gone. And this could cause some problems, for example, if the backend device type is file, some loop devices and blkback thread always lingers there forever after guest is destroyed, and this causes failure of umounting repositories unless rebooting the dom0. So stop all threads properly and return -EBUSY if any queue has inflight I/O. Signed-off-by: Annie Li Reviewed-by: Herbert van den Bergh Reviewed-by: Bhavesh Davda Reviewed-by: Adnan Misherfi --- drivers/block/xen-blkback/xenbus.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 792da68..2adb859 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -244,6 +244,7 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif) { struct pending_req *req, *n; unsigned int j, r; + bool busy = false; for (r = 0; r < blkif->nr_rings; r++) { struct xen_blkif_ring *ring = &blkif->rings[r]; @@ -261,8 +262,10 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif) * don't have any discard_io or other_io requests. So, checking * for inflight IO is enough. */ - if (atomic_read(&ring->inflight) > 0) - return -EBUSY; + if (atomic_read(&ring->inflight) > 0) { + busy = true; + continue; + } if (ring->irq) { unbind_from_irqhandler(ring->irq, ring); @@ -300,6 +303,9 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif) WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages)); ring->active = false; } + if (busy) + return -EBUSY; + blkif->nr_ring_pages = 0; /* * blkif->rings was allocated in connect_ring, so we should free it in -- 1.9.3