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. Kevin Wolf (12): 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 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 | 2 ++ include/block/nbd.h | 4 ++- include/io/channel.h | 9 +++-- include/sysemu/block-backend.h | 2 ++ nbd/nbd-internal.h | 19 ---------- block.c | 25 +++++++------- block/block-backend.c | 4 +-- block/nbd-client.c | 27 ++++++++++++++- hw/block/virtio-blk.c | 4 +++ io/channel.c | 10 ++++++ nbd/client.c | 63 ++++++++++++++++++++++++++++++++-- tests/test-bdrv-drain.c | 32 +++++++++++++++++ util/aio-posix.c | 3 +- 13 files changed, 162 insertions(+), 42 deletions(-) -- 2.20.1
