[Libguestfs] [libnbd PATCH v2 0/5] Avoid deadlock with in-flight commands

On v1, we discussed whether cmds_to_issue needed to be a list, since it never had more than one element. I played with the idea of making it a list, and allowing the client to queue up new commands regardless of whether the state machine is currently in READY. I also polished up the tmp demo into a bit more full-fledged example file, worth including since it also let me discover a hard-to-hit race with large NBD_CMD_WRITE vs. EAGAIN failures (now fixed). Eric Blake (5): lib: Refactor state event into command_common commands: Allow for a command queue states: Split ISSUE_COMMAND.SEND_REQUEST states: Allow in-flight read while writing next command examples: Add example to demonstrate just-fixed deadlock scenario .gitignore | 1 + examples/Makefile.am | 10 ++ examples/batched-read-write.c | 199 +++++++++++++++++++++++++++++++ generator/generator | 40 +++++-- generator/states-issue-command.c | 68 ++++++++--- generator/states.c | 6 + lib/disconnect.c | 17 +-- lib/internal.h | 10 ++ lib/rw.c | 41 ++++--- 9 files changed, 334 insertions(+), 58 deletions(-) create mode 100644 examples/batched-read-write.c -- 2.20.1