commit 9fd3171af9d7de2777bf38ce79c2fe3dd6f9a49e
author Kevin Wolf <kwolf@redhat.com> Thu Nov 14 15:37:12 2013 +0100
committer Kevin Wolf <kwolf@redhat.com> Fri Nov 29 13:40:37 2013 +0100
tree bed98d46ad99a96532a374da432e65b70170d1b6
parent b59b3d57737a0d40450f8232abd89e8986387402

block: Enable BDRV_O_SNAPSHOT with driver-specific options

In the case of snapshot=on, don't rely on the backing file path in the
temporary image any more, but override the backing file with the given
set of options. This way, block drivers that don't use a file name can
be accessed with snapshot=on, for example:

    -drive file.driver=nbd,file.host=localhost,snapshot=on

Which becomes internally something like:

    file.filename=/tmp/vl.AWQZCu,backing.file.driver=nbd,backing.file.host=localhost

Signed-off-by: Kevin Wolf <kwolf@redhat.com>