[Qemu-devel] [PATCH v10 00/16] Support streaming to an intermediate layer

[Alberto Garcia <berto@igalia.com>]

Hi all,

6 months after v9, and more than a year after v8, here's the new
version of the intermediate block streaming series.

There have been so many changes in QEMU since then that all patches in
this series are either new or have changed. Still, some of the most
important changes have been merged in separate series during all these
months (job IDs, support for "read-only" in the options QDict, etc.).

What's left can be roughly divided into:

- Patch 1: pause all block jobs during bdrv_reopen(). See the patch
  description for details.
- Patches 2-7: All jobs now block all BDSs that are involved in them,
  and not simply the root node.
- Patches 8-9: Support streaming to an intermediate layer. This
  is a rather simple change now and is similar to patches 2-7.
- Patch 10: Documentation (this one almost didn't change).
- Patches 11-16: Tests.

As you will see, the actual functional changes are rather simple. What
is there is many op blockers and many tests. I tried to write tests
for all scenarios that I could think of and I actually found a few
problems on the way, but I believe the code is stable now.

As always, comments and questions will be appreciated.

Berto

P.S. I don't include the backport-diff output because most patches are
new.

v10:
- Rebase the code.
- Pause block jobs during bdrv_reopen().
- Allow jobs in parallel again, and modify jobs to block all involved
  nodes, not just the root one.
- Add more tests.

v9: https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg00411.html
- Rebase the code
- Block the active layer in order to forbid other block jobs in the
  same chain.
- Split the patch that adds block_job_next() into 4 (new patches 1-4).
- Replace the test that performs several block-stream operations in
  parallel with one that check that they're forbidden.
- Remove patches that have already been merged.

v8: https://lists.gnu.org/archive/html/qemu-devel/2015-06/msg05754.html
- Rebased on top of Stefan's block branch (0a35bce416)
- The loop that pauses the block jobs in bdrv_drain_all() is now split
  in two: one that iterates the list of block jobs to stop them, and
  one that iterates the root bds in order to get the aio contexts.

v7: https://lists.gnu.org/archive/html/qemu-devel/2015-05/msg02580.html
- Rebased against the current master
- Updated bdrv_drain_all() to use the new block_job_next() API.

v6: https://lists.gnu.org/archive/html/qemu-devel/2015-04/msg03046.html
- fix the no-op test following Max's suggestions

v5: https://lists.gnu.org/archive/html/qemu-devel/2015-04/msg03006.html
- Fix a few typos
- Minor documentation updates
- Update test_stream_partial() to test no-ops
- New test case: test_stream_parallel()
- New test case: test_stream_overlapping()

v4: https://lists.gnu.org/archive/html/qemu-devel/2015-04/msg01878.html
- Refactor find_block_job to use the error from bdrv_lookup_bs()
- Don't use QERR_DEVICE_IN_USE in block_job_create() since we can be
  dealing with nodes now.
- Fix @device comment in the BlockJobInfo documentation
- stream_start(): simplify the bdrv_reopen() call and use
  bdrv_get_device_or_node_name() for error messages.
- Use a different variable name for BlockDriverState *i
- Documentation fixes in docs/live-block-ops.txt
- Update iotest 30 since now test_device_not_found() returns
  GenericError
- Fix test case test_stream_partial()
- Add new test case test_stream_intermediate()
- Fix typos

v3: https://lists.gnu.org/archive/html/qemu-devel/2015-04/msg00806.html
- Keep a list of block jobs and make qmp_query_block_jobs() iterate
  over it.

v2: https://lists.gnu.org/archive/html/qemu-devel/2015-03/msg04798.html
- The 'block-stream' command does not have a 'node-name' parameter
  anymore and reuses 'device' for that purpose.
- Block jobs can now be owned by any intermediate node, and not just
  by the ones at the root. query-block-jobs is updated to reflect that
  change.
- The 'device' parameter of all 'block-job-*' commands can now take a
  node name.
- The BlockJobInfo type and all BLOCK_JOB_* events report the node
  name in the 'device' field if the node does not have a device name.
- All intermediate nodes are blocked (and checked for blockers) during
  the streaming operation.

v1: https://lists.gnu.org/archive/html/qemu-devel/2015-02/msg04116.html

Alberto Garcia (16):
  block: Pause all jobs during bdrv_reopen_multiple()
  block: Add block_job_add_bdrv()
  block: Use block_job_add_bdrv() in mirror_start_job()
  block: Use block_job_add_bdrv() in backup_start()
  block: Check blockers in all nodes involved in a block-commit job
  block: Block all nodes involved in the block-commit operation
  block: Block all intermediate nodes in commit_active_start()
  block: Support streaming to an intermediate layer
  block: Add QMP support for streaming to an intermediate layer
  docs: Document how to stream to an intermediate layer
  qemu-iotests: Test streaming to an intermediate layer
  qemu-iotests: Test block-stream operations in parallel
  qemu-iotests: Test overlapping stream and commit operations
  qemu-iotests: Test block-stream and block-commit in parallel
  qemu-iotests: Add iotests.supports_quorum()
  qemu-iotests: Test streaming to a Quorum child

 block.c                       |  25 +++-
 block/backup.c                |   5 +-
 block/commit.c                |  10 ++
 block/mirror.c                |  11 +-
 block/stream.c                |  24 ++++
 blockdev.c                    |  22 +++-
 blockjob.c                    |  19 ++-
 docs/live-block-ops.txt       |  31 +++--
 include/block/blockjob.h      |  14 +++
 qapi/block-core.json          |  10 +-
 tests/qemu-iotests/030        | 276 +++++++++++++++++++++++++++++++++++++++++-
 tests/qemu-iotests/030.out    |   4 +-
 tests/qemu-iotests/041        |  27 ++---
 tests/qemu-iotests/139        |   3 +-
 tests/qemu-iotests/iotests.py |   5 +-
 15 files changed, 438 insertions(+), 48 deletions(-)

-- 
2.9.3