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mirror: fix early wake from sleep due to aio 

The mirror blockjob coroutine rate-limits itself by sleeping.  The
coroutine also performs I/O asynchronously so it's important that the
aio callback doesn't wake the coroutine early as that breaks
rate-limiting.

Reported-by: Joaquim Barrera <jbarrera@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2014-03-21 13:55:19 +01:00
parent cc8c9d6c6f
commit 7b770c720b
1 changed files with 8 additions and 1 deletions
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block/mirror.c
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@ -98,7 +98,14 @@ static void mirror_iteration_done(MirrorOp *op, int ret)
qemu_iovec_destroy(&op->qiov);
g_slice_free(MirrorOp, op);
qemu_coroutine_enter(s->common.co, NULL);
/* Enter coroutine when it is not sleeping. The coroutine sleeps to
* rate-limit itself. The coroutine will eventually resume since there is
* a sleep timeout so don't wake it early.
*/
if (s->common.busy) {
qemu_coroutine_enter(s->common.co, NULL);
}
}
static void mirror_write_complete(void *opaque, int ret)