v3 was here:
https://lists.gnu.org/archive/html/qemu-devel/2020-10/msg02305.html

Since then:
rebase to master
- patch 1 is new, fixing a theoretical bug in QAPI interaction and
 simplifying later patches
- patch 2, 4, and 6 are renamed to favor the term 'metadata context'
 [Markus], sadly 'git backport-diff' can't see through renames

Based-on: <20201009200720.1169904-1-eblake@redhat.com>
([PULL v3 0/8] NBD patches through 2020-10-08)

Also available at:
https://repo.or.cz/qemu/ericb.git/shortlog/refs/tags/nbd-alloc-depth-v4

001/7:[down] 'nbd: Utilize QAPI_CLONE for type conversion'
002/7:[down] 'nbd: Add new qemu:allocation-depth metadata context'
003/7:[0042] [FC] 'nbd: Add 'qemu-nbd -A' to expose allocation depth'
004/7:[down] 'nbd: Update qapi to support exporting multiple bitmaps'
005/7:[----] [-C] 'nbd: Simplify qemu bitmap context name'
006/7:[down] 'nbd: Refactor counting of metadata contexts'
007/7:[----] [-C] 'nbd: Allow export of multiple bitmaps for one device'

Eric Blake (7):
  nbd: Utilize QAPI_CLONE for type conversion
  nbd: Add new qemu:allocation-depth metadata context
  nbd: Add 'qemu-nbd -A' to expose allocation depth
  nbd: Update qapi to support exporting multiple bitmaps
  nbd: Simplify qemu bitmap context name
  nbd: Refactor counting of metadata contexts
  nbd: Allow export of multiple bitmaps for one device

 docs/interop/nbd.txt       |  27 ++++-
 docs/tools/qemu-nbd.rst    |   8 +-
 qapi/block-core.json       |   7 +-
 qapi/block-export.json     |  22 +++-
 include/block/nbd.h        |  12 ++-
 blockdev-nbd.c             |  29 +++--
 nbd/server.c               | 210 +++++++++++++++++++++++++++++--------
 qemu-nbd.c                 |  33 ++++--
 tests/qemu-iotests/291     |   6 +-
 tests/qemu-iotests/309     |  73 +++++++++++++
 tests/qemu-iotests/309.out |  22 ++++
 tests/qemu-iotests/group   |   1 +
 12 files changed, 364 insertions(+), 86 deletions(-)
 create mode 100755 tests/qemu-iotests/309
 create mode 100644 tests/qemu-iotests/309.out

-- 
2.28.0