From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Elder Subject: [PATCH, v2] rbd: do not allow remove of mounted-on image Date: Mon, 19 Nov 2012 17:42:49 -0600 Message-ID: <50AAC3F9.1040809@inktank.com> References: <50A65F15.6080807@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ie0-f174.google.com ([209.85.223.174]:41779 "EHLO mail-ie0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753203Ab2KSXmw (ORCPT ); Mon, 19 Nov 2012 18:42:52 -0500 Received: by mail-ie0-f174.google.com with SMTP id k13so7729715iea.19 for ; Mon, 19 Nov 2012 15:42:52 -0800 (PST) In-Reply-To: <50A65F15.6080807@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org There is no check in rbd_remove() to see if anybody holds open the image being removed. That's not cool. Add a simple open count that goes up and down with opens and closes (releases) of the device, and don't allow an rbd image to be removed if the count is non-zero. Protect the updates of the open count value with ctl_mutex to ensure the underlying rbd device doesn't get removed while concurrently being opened. Signed-off-by: Alex Elder --- v2: added ctl_mutex locking for rbd_open() and rbd_release() drivers/block/rbd.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) Index: b/drivers/block/rbd.c =================================================================== --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -255,6 +255,7 @@ struct rbd_device { /* sysfs related */ struct device dev; + unsigned long open_count; }; static DEFINE_MUTEX(ctl_mutex); /* Serialize open/close/setup/teardown */ @@ -356,8 +357,11 @@ static int rbd_open(struct block_device if ((mode & FMODE_WRITE) && rbd_dev->mapping.read_only) return -EROFS; + mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); rbd_get_dev(rbd_dev); set_device_ro(bdev, rbd_dev->mapping.read_only); + rbd_dev->open_count++; + mutex_unlock(&ctl_mutex); return 0; } @@ -366,7 +370,11 @@ static int rbd_release(struct gendisk *d { struct rbd_device *rbd_dev = disk->private_data; + mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING); + rbd_assert(rbd_dev->open_count > 0); + rbd_dev->open_count--; rbd_put_dev(rbd_dev); + mutex_unlock(&ctl_mutex); return 0; } @@ -3764,6 +3772,11 @@ static ssize_t rbd_remove(struct bus_typ goto done; } + if (rbd_dev->open_count) { + ret = -EBUSY; + goto done; + } + rbd_remove_all_snaps(rbd_dev); rbd_bus_del_dev(rbd_dev);