It turns out that our implementation of the hashing function is
endian-dependent and thus if used on various architectures the testsuite
may have different results. Work this around by mocking virHashCodeGen
to something which does not use bit operations instead of just setting a
deterministic seed.
With the new approach we are actually able to correctly detect node
names for the two instances of the same backing file.
Test images were created as:
qemu-img create -f qcow2 /var/lib/libvirt/images/base.qcow2 10M
qemu-img create -f qcow2 \
-o "backing_fmt=qcow2,backing_file=/var/lib/libvirt/images/base.qcow2 \
/var/lib/libvirt/images/a.qcow2
qemu-img create -f qcow2 \
-o "backing_fmt=qcow2,backing_file=/var/lib/libvirt/images/base.qcow2 \
/var/lib/libvirt/images/b.qcow2
and then used for two separate disks.
Reviewed-by: Eric Blake <eblake@redhat.com>
The node name and backing file name can be inferred from the hierarchy.
This will also help when converting to detect node names using
query-blockstats data.
Reviewed-by: Eric Blake <eblake@redhat.com>
Since we have to match the images by filename a common backing image
will break the detection process. Add a test case to see that the code
correctly did not continue the detection process.
