Description of problem:

When detaching a block device from a Xen domain using either 'virsh detach-disk' or, programmatically via virDomainDetachDevice(), the block device is left in a "busy" state and cannot be used from then on, by virsh or anyone else, until the domain is terminated. The detach operation achieves partial success, though, as the device does indeed disappear inside the guest domain.  On the same system, using the same domain and the same block device, xm block-attach and block-detach work flawlessly.

Version-Release number of selected component (if applicable):

libvirt / virsh 0.5.1 (problem also seen in 0.4.6)
on 2.6.26-1-xen-amd64

How reproducible:

consistently

Steps to Reproduce:

# losetup /dev/loop1 /path/to/partition.image
# virsh attach-disk instance-name /dev/loop1 hda1
Disk attached successfully
# virsh detach-disk instance-name hda1
Disk detached successfully
# virsh attach-disk instance-name /dev/loop1 hda1
libvir: Xen Daemon error : POST operation failed: xend_post: error from xen daemon: (xend.err 'Invalid Configuration: The file "/dev/loop1" is already used')