[libvirt] nfs and glusterfs volume drivers don't unmount their shares when detaching

[Xavier Queralt]

When attaching volumes from NFS or GlusterFS backends, nova mounts the share in a temporary directory, this is reused when attaching another volume from the same share so there is no need to mount it several times.

On the other hand, when disconnecting those volumes nova doesn't even try to unmount the share which may remain mounted and unused there. To clean up after detach, nova could at least try to umount the shares.

[Xavier Queralt (xqueralt-deactivatedaccount)]

Fix proposed to branch: master
Review: https://review.openstack.org/76558

[Tracy Jones (tjones-i)]

can make it into icehouse, but rc will not block for this

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/76558
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=dc716bd0ce77b56f4aabe54d6633b7f3bf9b0a5d
Submitter: Jenkins
Branch: master

commit dc716bd0ce77b56f4aabe54d6633b7f3bf9b0a5d
Author: Xavier Queralt <email address hidden>
Date: Wed Feb 26 15:09:30 2014 +0100

    Unmount the NFS and GlusterFS shares on detach

    When attaching an NFS or GlusterFS volume, nova mounts the share so it
    can be reused by other instances but it is not unmounted when detaching.

    This patch adds the disconnect_volume method to both drivers, which will
    try to unmount the share. If a volume in that share is still being used
    by another instance, the umount command will fail with the error 'target
    is busy' and we will ignore it. Any other error while unmounting will be
    properly logged. In any case the detach will fail because nova hasn't
    been able to unmount the share.

    Closes-Bug: #1285209
    Change-Id: I79289524541a88ad359b3465719055cd402b4e3d