On Mon, Jun 29, 2015 at 08:10:20AM +0200, Markus Armbruster wrote: > Alexander Yarygin <yary...@linux.vnet.ibm.com> writes: > > Markus Armbruster <arm...@redhat.com> writes: > > * Ignorant answer: I was told that the bdrv_drain_all()'s comment is > > obsolete and we can use bdrv_drain(). Here is a link to the old > > thread: http://marc.info/?l=qemu-devel&m=143154211017926&w=2. > > Kevin, Stefan, if the comment has become wrong, it needs to be redone. > Who's going to take care of it?
I couldn't think of a scenario where this patch is unsafe. The danger is that the I/O code path depends on something outside the AioContext. In that case you block in aio_poll(aio_context, true) forever without making progress. The thing the I/O request depends on will never finish. Code that accesses multiple BDSes puts them into the same AioContext, so this should not be a problem in practice. Stefan
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