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| author | Paolo Bonzini <pbonzini@redhat.com> | 2016-10-27 12:49:05 +0200 |
|---|---|---|
| committer | Fam Zheng <famz@redhat.com> | 2016-10-28 21:50:18 +0800 |
| commit | c9d1a56174339b0afdef63b7d151b38f4bb6dae5 (patch) | |
| tree | 1eb8359be422f1abbf98c5781cee063163861f67 /block/sheepdog.c | |
| parent | 9e944cb4744b527dd93aa989023739375a8880fb (diff) | |
| download | qemu-c9d1a56174339b0afdef63b7d151b38f4bb6dae5.tar.gz qemu-c9d1a56174339b0afdef63b7d151b38f4bb6dae5.tar.bz2 qemu-c9d1a56174339b0afdef63b7d151b38f4bb6dae5.zip | |
block: only call aio_poll on the current thread's AioContext
aio_poll is not thread safe; for example bdrv_drain can hang if
the last in-flight I/O operation is completed in the I/O thread after
the main thread has checked bs->in_flight.
The bug remains latent as long as all of it is called within
aio_context_acquire/aio_context_release, but this will change soon.
To fix this, if bdrv_drain is called from outside the I/O thread,
signal the main AioContext through a dummy bottom half. The event
loop then only runs in the I/O thread.
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1477565348-5458-18-git-send-email-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Diffstat (limited to 'block/sheepdog.c')
| -rw-r--r-- | block/sheepdog.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/block/sheepdog.c b/block/sheepdog.c index 16a5c1c28d..1fb917343a 100644 --- a/block/sheepdog.c +++ b/block/sheepdog.c @@ -702,6 +702,9 @@ out: srco->ret = ret; srco->finished = true; + if (srco->bs) { + bdrv_wakeup(srco->bs); + } } /* |