On 2018-09-03 16:34, Alberto Garcia wrote: > Block drivers allow opening their children using a reference to an > existing BlockDriverState. These references remain stored in the > 'options' and 'explicit_options' QDicts, but we don't need to keep > them once everything is open. > > What is more important, these values can become wrong if the children > change: > > $ qemu-img create -f qcow2 hd0.qcow2 10M > $ qemu-img create -f qcow2 hd1.qcow2 10M > $ qemu-img create -f qcow2 hd2.qcow2 10M > $ $QEMU -drive if=none,file=hd0.qcow2,node-name=hd0 \ > -drive if=none,file=hd1.qcow2,node-name=hd1,backing=hd0 \ > -drive file=hd2.qcow2,node-name=hd2,backing=hd1 > > After this hd2 has hd1 as its backing file. Now let's remove it using > block_stream: > > (qemu) block_stream hd2 0 hd0.qcow2 > > Now hd0 is the backing file of hd2, but hd2's options QDicts still > contain backing=hd1. > > Signed-off-by: Alberto Garcia <be...@igalia.com> > --- > block.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-)
Reviewed-by: Max Reitz <mre...@redhat.com>
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