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authorFam Zheng <famz@redhat.com>2016-02-02 10:12:24 +0800
committerStefan Hajnoczi <stefanha@redhat.com>2016-02-09 13:52:26 +0000
commit794f01414f9f4c4d0c6f1961154674961941c197 (patch)
treea2fb49a44557ac1899e2c37c591a4a5e763edea4 /blockjob.c
parentad523bca56a7202d2498c550a41be5c986c4d33c (diff)
downloadqemu-arm-794f01414f9f4c4d0c6f1961154674961941c197.tar.gz
blockjob: Fix hang in block_job_finish_sync
With a mirror job running on a virtio-blk dataplane disk, sending "q" to HMP will cause a dead loop in block_job_finish_sync. This is because the aio_poll() only processes the AIO context of bs which has no more work to do, while the main loop BH that is scheduled for setting the job->completed flag is never processed. Fix this by adding a flag in BlockJob structure, to track which context to poll for the block job to make progress. Its value is set to true when block_job_coroutine_complete() is called, and is checked in block_job_finish_sync to determine which context to poll. Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com> Message-id: 1454379144-29807-1-git-send-email-famz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'blockjob.c')
-rw-r--r--blockjob.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/blockjob.c b/blockjob.c
index a402181835..9fc37ca965 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -296,7 +296,9 @@ static int block_job_finish_sync(BlockJob *job,
return -EBUSY;
}
while (!job->completed) {
- aio_poll(bdrv_get_aio_context(bs), true);
+ aio_poll(job->deferred_to_main_loop ? qemu_get_aio_context() :
+ bdrv_get_aio_context(bs),
+ true);
}
ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
block_job_unref(job);
@@ -470,6 +472,7 @@ static void block_job_defer_to_main_loop_bh(void *opaque)
aio_context = bdrv_get_aio_context(data->job->bs);
aio_context_acquire(aio_context);
+ data->job->deferred_to_main_loop = false;
data->fn(data->job, data->opaque);
aio_context_release(aio_context);
@@ -489,6 +492,7 @@ void block_job_defer_to_main_loop(BlockJob *job,
data->aio_context = bdrv_get_aio_context(job->bs);
data->fn = fn;
data->opaque = opaque;
+ job->deferred_to_main_loop = true;
qemu_bh_schedule(data->bh);
}