tree da45f57f7fcd1a09b6e2835c04cd93ff95737a37
parent 7324c10f96c821b00d691e2c8ced67d8536bf1d6
author Max Reitz <mreitz@redhat.com> 1423600127 -0500
committer Kevin Wolf <kwolf@redhat.com> 1425992541 +0100

qcow2: Use unsigned addend for update_refcount()

update_refcount() and qcow2_update_cluster_refcount() currently take a
signed addend. At least one caller passes a value directly derived from
an absolute refcount that should be reached ("l2_refcount - 1" in
expand_zero_clusters_in_l1()). Therefore, the addend should be unsigned
as well; this will be especially important for 64 bit refcounts.

Because update_refcount() then no longer knows whether the refcount
should be increased or decreased, it now requires an additional flag
which specified exactly that. The same applies to
qcow2_update_cluster_refcount().

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>