[PATCH v2 0/4] Introduce 'yank' oob qmp command to recover from hanging qemu

[Lukas Straub]

Hello Everyone,
In many cases, if qemu has a network connection (qmp, migration, chardev, etc.)
to some other server and that server dies or hangs, qemu hangs too.
These patches introduce the new 'yank' out-of-band qmp command to recover from
these kinds of hangs. The different subsystems register callbacks which get
executed with the yank command. For example the callback can shutdown() a
socket. This is intended for the colo use-case, but it can be used for other
things too of course.

Regards,
Lukas Straub

v2:
 -don't touch io/ code anymore
 -always register yank functions
 -'yank' now takes a list of instances to yank
 -'query-yank' returns a list of yankable instances

Lukas Straub (4):
  Introduce yank feature
  block/nbd.c: Add yank feature
  chardev/char-socket.c: Add yank feature
  migration: Add yank feature

 Makefile.objs                 |   1 +
 block/nbd.c                   | 101 ++++++++++++--------
 chardev/char-socket.c         |  24 +++++
 migration/migration.c         |   9 ++
 migration/qemu-file-channel.c |   6 ++
 migration/socket.c            |  11 +++
 qapi/misc.json                |  45 +++++++++
 softmmu/vl.c                  |   2 +
 yank.c                        | 174 ++++++++++++++++++++++++++++++++++
 yank.h                        |  69 ++++++++++++++
 10 files changed, 405 insertions(+), 37 deletions(-)
 create mode 100644 yank.c
 create mode 100644 yank.h

--
2.20.1

pgpdxF5n62ATr.pgp
Description: OpenPGP digital signature