Merge tag 'pull-nbd-2023-07-19' of https://repo.or.cz/qemu/ericb into staging

Merge tag 'pull-nbd-2023-07-19' of https://repo.or.cz/qemu/ericb into staging

NBD patches through 2023-07-19

- Denis V. Lunev: fix hang with 'ssh ... "qemu-nbd -c"'
- Eric Blake: preliminary work towards NBD 64-bit extensions

# -----BEGIN PGP SIGNATURE-----
#
# iQEzBAABCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAmS4RwcACgkQp6FrSiUn
# Q2pXfQf/clnttPdw9BW2cJltFRKeMeZrgn8mut0S7jhC0DWIy6zanzp07MylryHP
# EyJ++dCbLEg8mueThL/n5mKsTS/OECtfZO9Ot11WmZqDZVtLKorfmy7YVI3VwMjI
# yQqrUIwiYxzZOkPban/MXofY6vJmuia5aGkEmYUyKiHvsLF3Hk2gHPB/qa2S+U6I
# QDmC032/L+/LgVkK5r/1vamwJNP29QI4DNp3RiTtcMK5sEZJfMsAZSxFDDdH2pqi
# 5gyVqw0zNl3vz6znoVy0XZ/8OUVloPKHswyf7xLlBukY1GL5D+aiXz2ilwBvk9aM
# SoZzYvaOOBDyJhSjapOvseTqXTNeqQ==
# =TB9t
# -----END PGP SIGNATURE-----
# gpg: Signature made Wed 19 Jul 2023 21:26:47 BST
# gpg:                using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full]
# gpg:                 aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* tag 'pull-nbd-2023-07-19' of https://repo.or.cz/qemu/ericb:
  nbd: Use enum for various negotiation modes
  nbd/client: Add safety check on chunk payload length
  nbd/client: Simplify cookie vs. index computation
  nbd: s/handle/cookie/ to match NBD spec
  nbd/server: Refactor to pass full request around
  nbd/server: Prepare for alternate-size headers
  nbd: Consistent typedef usage in header
  nbd/client: Use smarter assert
  qemu-nbd: make verbose bool and local variable in main()
  qemu-nbd: handle dup2() error when qemu-nbd finished setup process
  qemu-nbd: properly report error on error in dup2() after qemu_daemon()
  qemu-nbd: properly report error if qemu_daemon() is failed
  qemu-nbd: fix regression with qemu-nbd --fork run over ssh
  qemu-nbd: pass structure into nbd_client_thread instead of plain char*

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>