[Qemu-block] [PATCH v3 0/3] Disallow snapshots if the overlay doesn't support backing files

[Alberto Garcia]

We are currently allowing snapshots in cases like this one:

       { 'execute': 'blockdev-add', 'arguments':
         { 'options': { 'driver': 'qcow2',
                        'node-name': 'new0',
                        'file': { 'driver': 'file',
                                  'filename': 'new.qcow2',
                                  'node-name': 'file0' } } } }

       { 'execute': 'blockdev-snapshot', 'arguments':
         { 'node': 'virtio0',
           'overlay': 'file0' } }

This patch forbids snapshots if the overlay node does not support
backing files.

Regards,

Berto

v3:
- patch 2: new patch to remove all the existing inner quotation marks in
  test 085 [Max, Eric]
- patch 3: fix description and remove inner quotation marks [Max, Eric]

v2: https://lists.gnu.org/archive/html/qemu-block/2015-11/msg00005.html
- Disallow snapshots if new_bs->drv->supports_backing is false [Max]

v1: https://lists.gnu.org/archive/html/qemu-devel/2015-10/msg06875.html
- Initial version.

Alberto Garcia (3):
  block: Disallow snapshots if the overlay doesn't support backing files
  block: Remove inner quotation marks in iotest 085
  block: test 'blockdev-snapshot' using a file BDS as the overlay

 blockdev.c                 |  5 +++++
 tests/qemu-iotests/085     | 26 ++++++++++++++++++--------
 tests/qemu-iotests/085.out |  4 ++++
 3 files changed, 27 insertions(+), 8 deletions(-)

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2.6.2