On Tue, Jun 17, 2014 at 05:53:56PM -0400, Jeff Cody wrote: > On some image chains, QEMU may not always be able to resolve the > filenames properly, when updating the backing file of an image > after a block job. > > For instance, certain relative pathnames may fail, or drives may > have been specified originally by file descriptor (e.g. /dev/fd/???), > or a relative protocol pathname may have been used. > > In these instances, QEMU may lack the information to be able to make > the correct choice, but the user or management layer most likely does > have that knowledge. > > With this extension to the block-stream api, the user is able to change > the backing file of the active layer as part of the block-stream > operation. > > This allows the change to be 'safe', in the sense that if the attempt > to write the active image metadata fails, then the block-stream > operation returns failure, without disrupting the guest. > > If a backing file string is not specified in the command, the backing > file string to use is determined in the same manner as it was > previously. > > Reviewed-by: Eric Blake <ebl...@redhat.com> > Signed-off-by: Jeff Cody <jc...@redhat.com> > --- > block/stream.c | 11 +++++------ > blockdev.c | 12 ++++++++++++ > hmp.c | 3 ++- > qapi/block-core.json | 18 +++++++++++++++++- > qmp-commands.hx | 2 +- > 5 files changed, 37 insertions(+), 9 deletions(-)
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
pgpVzgePRVJhG.pgp
Description: PGP signature