Am 31.01.2022 um 14:59 hat Hanna Reitz geschrieben: > qemu-img convert documents the backing file and backing format options > as follows: > [-B backing_file [-F backing_fmt]] > whereas qemu-img create has this: > [-b backing_file] [-F backing_fmt] > > That is, for convert, we document that -F cannot be given without -B, > while for create, way say that they are independent. > > Indeed, it is technically possible to give -F without -b, because it is > left to the block driver to decide whether this is an error or not, so > sometimes it is: > > $ qemu-img create -f qed -F qed test.qed 64M > Formatting 'test.qed', fmt=qed size=67108864 backing_fmt=qed [...] > > And sometimes it is not: > > $ qemu-img create -f qcow2 -F qcow2 test.qcow2 64M > Formatting 'test.qcow2', fmt=qcow2 cluster_size=65536 [...] > qemu-img: test.qcow2: Backing format cannot be used without backing file > > Generally, it does not make much sense, though, and users should only > give -F with -b, so document it that way, as we have already done for > qemu-img convert (commit 1899bf47375ad40555dcdff12ba49b4b8b82df38). > > Reported-by: Tingting Mao <ti...@redhat.com> > Signed-off-by: Hanna Reitz <hre...@redhat.com>
Thanks, applied to the block branch. Kevin
