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[RFC PATCH 00/18] Add qemu-storage-daemon
From: |
Kevin Wolf |
Subject: |
[RFC PATCH 00/18] Add qemu-storage-daemon |
Date: |
Thu, 17 Oct 2019 15:01:46 +0200 |
This series adds a new tool 'qemu-storage-daemon', which can be used to
export and perform operations on block devices. There is some overlap
between qemu-img/qemu-nbd and the new qemu-storage-daemon, but there are
a few important differences:
* The qemu-storage-daemon has QMP support. The command set is obviously
restricted compared to the system emulator because there is no guest,
but all of the block operations are present.
This means that it can access advanced options or operations that the
qemu-img command line doesn't expose. For example, blockdev-create is
a lot more powerful than 'qemu-img create', and qemu-storage-daemon
allows to execute it without starting a guest.
Compared to qemu-nbd it means that, for example, block jobs can now be
executed on the server side, and backing chains shared by multiple VMs
can be modified this way.
* The existing tools all have a separately invented one-off syntax for
the job at hand, which usually comes with restrictions compared to the
system emulator. qemu-storage-daemon shares the same syntax with the
system emulator for most options and prefers QAPI based interfaces
where possible (such as --blockdev), so it should be easy to make use
of in libvirt.
* While this series implements only NBD exports, the storage daemon is
intended to serve multiple protocols and its syntax reflects this. In
the past, we had proposals to add new one-off tools for exporting over
new protocols like FUSE or TCMU.
With a generic storage daemon, additional export methods have a home
without adding a new tool for each of them.
I'm posting this as an RFC mainly for two reasons:
1. The monitor integration, which could be argued to be a little hackish
(some generated QAPI source files are built from a separate QAPI
schema, but the per-module ones are taken from the system emulator)
and Markus will want to have a closer look there. But from the IRC
discussions we had, we seem to agree on the general approach here.
2. I'm not completely sure if the command line syntax is the final
version that we want to support long-term. Many options directly use
QAPI visitors (--blockdev, --export, --nbd-server) and should be
fine. However, others use QemuOpts (--chardev, --monitor, --object).
This is the same as in the system emulator, so we wouldn't be adding
a new problem, but as there was talk about QAPIfying the command
line, and I wouldn't want later syntax changes or adding lots of
compatibility code to a new tool, I thought we should probably
discuss whether QAPIfying from the start would be an option.
I would like to have something merged for 4.2, but I'm considering
marking the whole tool as experimental and unstable ABI by requiring a
command line option like --experimental for the tool to even start if we
know that we want to change some things later.
This series is based on:
* [PATCH] blockdev: Use error_report() in hmp_commit()
* [PATCH 0/7] qapi: Cleanups and test speedup
Based-on: <address@hidden>
Based-on: <address@hidden>
Kevin Wolf (18):
qemu-storage-daemon: Add barebone tool
qemu-storage-daemon: Add --object option
stubs: Add arch_type
stubs: Add blk_by_qdev_id()
qemu-storage-daemon: Add --blockdev option
qemu-storage-daemon: Add --nbd-server option
blockdev-nbd: Boxed argument type for nbd-server-add
qemu-storage-daemon: Add --export option
qemu-storage-daemon: Add main loop
qemu-storage-daemon: Add --chardev option
monitor: Move monitor option parsing to monitor/monitor.c
stubs: Update monitor stubs for qemu-storage-daemon
qapi: Create module 'monitor'
monitor: Create monitor/qmp-cmds-monitor.c
qapi: Support empty modules
qapi: Create 'pragma' module
monitor: Move qmp_query_qmp_schema to qmp-cmds-monitor.c
qemu-storage-daemon: Add --monitor option
qapi/block.json | 65 ++++-
qapi/misc.json | 212 ---------------
qapi/monitor.json | 218 +++++++++++++++
qapi/pragma.json | 24 ++
qapi/qapi-schema.json | 26 +-
storage-daemon/qapi/qapi-schema.json | 15 ++
configure | 2 +-
include/block/nbd.h | 1 +
include/monitor/monitor.h | 4 +
include/sysemu/arch_init.h | 2 +
include/sysemu/sysemu.h | 1 -
monitor/monitor-internal.h | 4 +
blockdev-nbd.c | 30 ++-
monitor/hmp-cmds.c | 22 +-
monitor/misc.c | 126 ---------
monitor/monitor.c | 52 ++++
monitor/qmp-cmds-monitor.c | 169 ++++++++++++
monitor/qmp-cmds.c | 15 +-
monitor/qmp.c | 2 +-
qemu-storage-daemon.c | 326 +++++++++++++++++++++++
stubs/arch_type.c | 4 +
stubs/blk-by-qdev-id.c | 9 +
stubs/monitor-core.c | 21 ++
stubs/monitor.c | 15 +-
tests/qmp-test.c | 2 +-
ui/gtk.c | 1 +
vl.c | 45 +---
Makefile | 34 +++
Makefile.objs | 9 +
block/Makefile.objs | 2 +-
monitor/Makefile.objs | 5 +-
qapi/Makefile.objs | 9 +-
qom/Makefile.objs | 1 +
scripts/qapi/gen.py | 5 +
scripts/qapi/schema.py | 9 +
storage-daemon/Makefile.objs | 1 +
storage-daemon/qapi/Makefile.objs | 1 +
stubs/Makefile.objs | 3 +
tests/qapi-schema/comments.out | 2 +
tests/qapi-schema/doc-bad-section.out | 2 +
tests/qapi-schema/doc-good.out | 2 +
tests/qapi-schema/empty.out | 2 +
tests/qapi-schema/event-case.out | 2 +
tests/qapi-schema/include-repetition.out | 4 +
tests/qapi-schema/include-simple.out | 3 +
tests/qapi-schema/indented-expr.out | 2 +
tests/qapi-schema/qapi-schema-test.out | 4 +
47 files changed, 1052 insertions(+), 463 deletions(-)
create mode 100644 qapi/monitor.json
create mode 100644 qapi/pragma.json
create mode 100644 storage-daemon/qapi/qapi-schema.json
create mode 100644 monitor/qmp-cmds-monitor.c
create mode 100644 qemu-storage-daemon.c
create mode 100644 stubs/arch_type.c
create mode 100644 stubs/blk-by-qdev-id.c
create mode 100644 stubs/monitor-core.c
create mode 100644 storage-daemon/Makefile.objs
create mode 100644 storage-daemon/qapi/Makefile.objs
--
2.20.1
- [RFC PATCH 00/18] Add qemu-storage-daemon,
Kevin Wolf <=
- [RFC PATCH 01/18] qemu-storage-daemon: Add barebone tool, Kevin Wolf, 2019/10/17
- [RFC PATCH 02/18] qemu-storage-daemon: Add --object option, Kevin Wolf, 2019/10/17
- [RFC PATCH 03/18] stubs: Add arch_type, Kevin Wolf, 2019/10/17
- [RFC PATCH 05/18] qemu-storage-daemon: Add --blockdev option, Kevin Wolf, 2019/10/17
- [RFC PATCH 04/18] stubs: Add blk_by_qdev_id(), Kevin Wolf, 2019/10/17
- [RFC PATCH 06/18] qemu-storage-daemon: Add --nbd-server option, Kevin Wolf, 2019/10/17
- [RFC PATCH 07/18] blockdev-nbd: Boxed argument type for nbd-server-add, Kevin Wolf, 2019/10/17
- [RFC PATCH 10/18] qemu-storage-daemon: Add --chardev option, Kevin Wolf, 2019/10/17
- [RFC PATCH 08/18] qemu-storage-daemon: Add --export option, Kevin Wolf, 2019/10/17