Re: [Qemu-devel] [PATCH for-2.11] block: Keep strong reference when draining all BDS

[Fam Zheng]

On Fri, 11/10 16:23, Max Reitz wrote:
> But bdrv_unref() is safe only in the main loop.  Without having checked,
> I'm not sure whether all callers of bdrv_next() are running in the main
> loop.

They must be. The reasoning is simple:

1) one needs to acquire the ctx of all the BDSes for safe access;
2) only main loop can acquire any BDS' ctx;

So there is no way bdrv_next can work in an IOThread.

Fam