]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
rbd: drop parent_ref in rbd_dev_unprobe() unconditionally
authorIlya Dryomov <idryomov@redhat.com>
Mon, 19 Jan 2015 09:06:14 +0000 (12:06 +0300)
committerIlya Dryomov <idryomov@redhat.com>
Wed, 28 Jan 2015 13:12:02 +0000 (16:12 +0300)
commite69b8d414f948c242ad9f3eb2b7e24fba783dbbd
tree9c3a0b4804207906ec2b958496aa849d9d11396f
parentae43e9d05eb4bd324155292f889fbd001c4faea8
rbd: drop parent_ref in rbd_dev_unprobe() unconditionally

This effectively reverts the last hunk of 392a9dad7e77 ("rbd: detect
when clone image is flattened").

The problem with parent_overlap != 0 condition is that it's possible
and completely valid to have an image with parent_overlap == 0 whose
parent state needs to be cleaned up on unmap.  The next commit, which
drops the "clone image now standalone" logic, opens up another window
of opportunity to hit this, but even without it

    # cat parent-ref.sh
    #!/bin/bash
    rbd create --image-format 2 --size 1 foo
    rbd snap create foo@snap
    rbd snap protect foo@snap
    rbd clone foo@snap bar
    rbd resize --allow-shrink --size 0 bar
    rbd resize --size 1 bar
    DEV=$(rbd map bar)
    rbd unmap $DEV

leaves rbd_device/rbd_spec/etc and rbd_client along with ceph_client
hanging around.

My thinking behind calling rbd_dev_parent_put() unconditionally is that
there shouldn't be any requests in flight at that point in time as we
are deep into unmap sequence.  Hence, even if rbd_dev_unparent() caused
by flatten is delayed by in-flight requests, it will have finished by
the time we reach rbd_dev_unprobe() caused by unmap, thus turning
unconditional rbd_dev_parent_put() into a no-op.

Fixes: http://tracker.ceph.com/issues/10352
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Reviewed-by: Josh Durgin <jdurgin@redhat.com>
Reviewed-by: Alex Elder <elder@linaro.org>
drivers/block/rbd.c