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[PATCH v2 00/11] block: Re-enable the graph lock
From: |
Kevin Wolf |
Subject: |
[PATCH v2 00/11] block: Re-enable the graph lock |
Date: |
Mon, 5 Jun 2023 10:57:00 +0200 |
This series fixes the deadlock that was observed before commit ad128dff
('graph-lock: Disable locking for now'), which just disabled the graph
lock completely as a workaround to get 8.0.1 stable.
In theory the problem is simple: We can't poll while still holding the
lock of a different AioContext. So bdrv_graph_wrlock() just needs to
drop that lock before it polls. However, there are a number of callers
that don't even hold the AioContext lock they are supposed to hold, so
temporarily unlocking tries to unlock a mutex that isn't locked,
resulting in assertion failures.
Therefore, much of this series is just for fixing AioContext locking
correctness. It is only the last two patches that actually fix the
deadlock and reenable the graph locking.
v2:
- Fixed patch 2 to actually lock the correct AioContext even if the
device doesn't support iothreads
- Improved the commit message for patch 7 [Eric]
- Fixed mismerge in patch 11 (v1 incorrectly left an #if 0 around)
Kevin Wolf (11):
iotests: Test active commit with iothread and background I/O
qdev-properties-system: Lock AioContext for blk_insert_bs()
test-block-iothread: Lock AioContext for blk_insert_bs()
block: Fix AioContext locking in bdrv_open_child()
block: Fix AioContext locking in bdrv_attach_child_common()
block: Fix AioContext locking in bdrv_reopen_parse_file_or_backing()
block: Fix AioContext locking in bdrv_open_inherit()
block: Fix AioContext locking in bdrv_open_backing_file()
blockjob: Fix AioContext locking in block_job_add_bdrv()
graph-lock: Unlock the AioContext while polling
Revert "graph-lock: Disable locking for now"
include/block/graph-lock.h | 6 +-
block.c | 103 ++++++++++++++++--
block/graph-lock.c | 42 ++++---
blockjob.c | 17 ++-
hw/core/qdev-properties-system.c | 8 +-
tests/unit/test-block-iothread.c | 7 +-
.../tests/iothreads-commit-active | 85 +++++++++++++++
.../tests/iothreads-commit-active.out | 23 ++++
8 files changed, 250 insertions(+), 41 deletions(-)
create mode 100755 tests/qemu-iotests/tests/iothreads-commit-active
create mode 100644 tests/qemu-iotests/tests/iothreads-commit-active.out
--
2.40.1
- [PATCH v2 00/11] block: Re-enable the graph lock,
Kevin Wolf <=
- [PATCH v2 01/11] iotests: Test active commit with iothread and background I/O, Kevin Wolf, 2023/06/05
- [PATCH v2 03/11] test-block-iothread: Lock AioContext for blk_insert_bs(), Kevin Wolf, 2023/06/05
- [PATCH v2 04/11] block: Fix AioContext locking in bdrv_open_child(), Kevin Wolf, 2023/06/05
- [PATCH v2 06/11] block: Fix AioContext locking in bdrv_reopen_parse_file_or_backing(), Kevin Wolf, 2023/06/05
- [PATCH v2 07/11] block: Fix AioContext locking in bdrv_open_inherit(), Kevin Wolf, 2023/06/05
- [PATCH v2 09/11] blockjob: Fix AioContext locking in block_job_add_bdrv(), Kevin Wolf, 2023/06/05
- [PATCH v2 02/11] qdev-properties-system: Lock AioContext for blk_insert_bs(), Kevin Wolf, 2023/06/05
- [PATCH v2 05/11] block: Fix AioContext locking in bdrv_attach_child_common(), Kevin Wolf, 2023/06/05
- [PATCH v2 11/11] Revert "graph-lock: Disable locking for now", Kevin Wolf, 2023/06/05