On 20.09.18 18:19, Kevin Wolf wrote: > bdrv_drain_poll_top_level() was buggy because it didn't release the > AioContext lock of the node to be drained before calling aio_poll(). > This way, callbacks called by aio_poll() would possibly take the lock a > second time and run into a deadlock with a nested AIO_WAIT_WHILE() call. > > However, it turns out that the aio_poll() call isn't actually needed any > more. It was introduced in commit 91af091f923, which is effectively > reverted by this patch. The cases it was supposed to fix are now covered > by bdrv_drain_poll(), which waits for block jobs to reach a quiescent > state. > > Signed-off-by: Kevin Wolf <kw...@redhat.com> > Reviewed-by: Fam Zheng <f...@redhat.com> > Reviewed-by: Max Reitz <mre...@redhat.com> > --- > block/io.c | 8 -------- > 1 file changed, 8 deletions(-)
Hm... While looking at iotest 129 (which I think is broken because it
tries to use BB-level throttling which doesn't do anything for the
mirror job), I noticed this:
$ x86_64-softmmu/qemu-system-x86_64 \
-object throttle-group,id=tg0 \
-drive node-name=node0,driver=throttle,\
throttle-group=tg0,file.driver=qcow2,file.file.driver=file,\
file.file.filename=/tmp/src.qcow2 -qmp stdio \
<<EOF
{"execute":"qmp_capabilities"}
{"execute":"drive-mirror","arguments":{"device":"node0",
"target":"/tmp/tgt.qcow2","sync":"full","format":"qcow2",
"mode":"absolute-paths","job-id":"mirror-job0"}}
{"execute":"block-job-cancel",
"arguments":{"device":"mirror-job0","force":true}}
{"execute":"quit"}
EOF
[...]
qemu-system-x86_64: block/block-backend.c:2211: blk_root_drained_end:
Assertion `blk->quiesce_counter' failed.
[1] 2722 abort (core dumped) x86_64-softmmu/qemu-system-x86_64
-object throttle-group,id=tg0 -drive -qmp
(Which worked before commit 4cf077b59fc73eec29f8b7d082919dbb278bdc86,
i.e. this one.)
Max
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