On 16/09/2015 10:22, Wen Congyang wrote:
>>> >> if (exp->blk) {
>>> >> + bdrv_drain(blk_bs(exp->blk));
>>> >> blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
>>> >> blk_aio_detach, exp);
>>> >> blk_unref(exp->blk);
>> >
>> > I think a better fix is to move the whole "if" to nbd_export_put. In
>> > fact, nbd_export_close is wrong because exp can be freed by
>> > nbd_export_close's call to nbd_export_put.
> OK, I will fix it in the next version.
To be clear, the bug is pre-existing (commit 38b54b6, "nbd: use
BlockDriverState refcnt", 2013-08-23).
Paolo
