From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Elder Subject: [PATCH 2/5] rbd: protect against concurrent unmaps Date: Fri, 31 May 2013 20:20:26 -0500 Message-ID: <51A94C5A.20807@inktank.com> References: <51A94BC0.4080703@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ie0-f171.google.com ([209.85.223.171]:50027 "EHLO mail-ie0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755098Ab3FABU2 (ORCPT ); Fri, 31 May 2013 21:20:28 -0400 Received: by mail-ie0-f171.google.com with SMTP id s9so5770988iec.16 for ; Fri, 31 May 2013 18:20:28 -0700 (PDT) Received: from [172.22.22.4] (c-71-195-31-37.hsd1.mn.comcast.net. [71.195.31.37]) by mx.google.com with ESMTPSA id ji5sm6490138igb.0.2013.05.31.18.20.27 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 31 May 2013 18:20:27 -0700 (PDT) In-Reply-To: <51A94BC0.4080703@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel Make sure two concurrent unmap operations on the same rbd device won't collide, by only proceeding with the removal and cleanup of a device if is not already underway. Signed-off-by: Alex Elder --- drivers/block/rbd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 716ef1f..380940d 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -5153,6 +5153,7 @@ static ssize_t rbd_remove(struct bus_type *bus, struct list_head *tmp; int dev_id; unsigned long ul; + bool already = false; int ret; ret = strict_strtoul(buf, 10, &ul); @@ -5180,11 +5181,12 @@ static ssize_t rbd_remove(struct bus_type *bus, if (rbd_dev->open_count) ret = -EBUSY; else - set_bit(RBD_DEV_FLAG_REMOVING, &rbd_dev->flags); + already = test_and_set_bit(RBD_DEV_FLAG_REMOVING, + &rbd_dev->flags); spin_unlock_irq(&rbd_dev->lock); } spin_unlock(&rbd_dev_list_lock); - if (ret < 0) + if (ret < 0 || already) goto done; rbd_bus_del_dev(rbd_dev); -- 1.7.9.5