[0/5] Fix not white-listed copy-before-write

Message

Vladimir Sementsov-Ogievskiy Sept. 20, 2021, 11:55 a.m. UTC

Hi all!

As reported in https://bugzilla.redhat.com/show_bug.cgi?id=2004812
backup don't work when copy-before-write is not white-listed.

Yes, we do need copy-before-write filter for backup to work (like we
always use copy-on-read filter in block-stream).
The problem is that in bdrv_insert_node() (called to insert filters
internally) we use bdrv_open(), which does a lot of things we don't need
for internal node creation and among them check the white-list.

Backup job should of course work when copy-before-write is not
white-listed. As well, block-stream should work with not-white-listed
copy-on-read. White-list is for user, not for internal implementation.

Following Kevin's suggestion fix the problem by implementing a version
of bdrv_new_open_driver() that supports QDict of options, and use it
instead of bdrv_open().

Vladimir Sementsov-Ogievskiy (5):
  block: implement bdrv_new_open_driver_opts()
  block: bdrv_insert_node(): fix and improve error handling
  block: bdrv_insert_node(): doc and style
  block: bdrv_insert_node(): don't use bdrv_open()
  iotests/image-fleecing: declare requirement of copy-before-write

 include/block/block.h                   |  4 ++
 block.c                                 | 77 ++++++++++++++++++++-----
 tests/qemu-iotests/tests/image-fleecing |  1 +
 3 files changed, 68 insertions(+), 14 deletions(-)