Background for this series is the following bug report, which is about a
crash with virtio-blk + iothread and request resubmission for werror/rerror:
https://bugzilla.redhat.com/show_bug.cgi?id=1671173
The reason is that bdrv_set_aio_context() didn't correctly quiesce
everything. Instead, it had a local hack to call aio_poll() for the
source AioContext, which covered some, but not all cases, and is wrong
because you can only call aio_poll() from the home thread.
So this series tries to make bdrv_drain() actually drain the known cases
(fixes virtio-blk and the NBD client) and use the regular drain
functions in bdrv_set_aio_context() instead of open-coding something
similar.
v2:
- New patch 5: Remove now redundant assignments [Paolo]
- Patch 8 (was 7): Instead of using aio_co_schedule() to switch the
AioContext and modifying the coroutine code, enter the coroutine in a
BH in the new AioContext and bdrv_dec_in_flight() in that BH [Paolo]
- Patch 12 (was 11): Cover new == old case in comment [Eric]
Kevin Wolf (13):
block-backend: Make blk_inc/dec_in_flight public
virtio-blk: Increase in_flight for request restart BH
nbd: Restrict connection_co reentrance
io: Make qio_channel_yield() interruptible
io: Remove redundant read/write_coroutine assignments
nbd: Move nbd_read_eof() to nbd/client.c
nbd: Use low-level QIOChannel API in nbd_read_eof()
nbd: Increase bs->in_flight during AioContext switch
block: Don't poll in bdrv_set_aio_context()
block: Fix AioContext switch for drained node
test-bdrv-drain: AioContext switch in drained section
block: Use normal drain for bdrv_set_aio_context()
aio-posix: Assert that aio_poll() is always called in home thread
block/nbd-client.h | 1 +
include/block/nbd.h | 3 +-
include/io/channel.h | 9 ++++--
include/sysemu/block-backend.h | 2 ++
nbd/nbd-internal.h | 19 -------------
block.c | 26 ++++++++---------
block/block-backend.c | 4 +--
block/nbd-client.c | 36 +++++++++++++++++++++--
hw/block/virtio-blk.c | 4 +++
io/channel.c | 24 ++++++++++------
nbd/client.c | 52 ++++++++++++++++++++++++++++++++--
tests/test-bdrv-drain.c | 32 +++++++++++++++++++++
util/aio-posix.c | 3 +-
13 files changed, 164 insertions(+), 51 deletions(-)
--
2.20.1