Re: [PULL 09/28] block: bdrv/blk_co_unref() for calls in coroutine context

[Kevin Wolf]

Am 11.05.2023 um 17:32 hat Michael Tokarev geschrieben:
> 10.05.2023 15:20, Kevin Wolf wrote:
> > These functions must not be called in coroutine context, because they
> > need write access to the graph.
> 
> How important for this and 2 surrounding changes to be for 7.2-stable
> (if we'll ever release one)? It smells like real bugs are being fixed
> here, is it ever possible to hit those in 7.2?
> 
> Provided that whole no_coroutine_fn &Co infrastructure is missing there,
> including the no_co_wrapper parts?  It's not difficult to back-port some
> of that stuff to 7.2.

In theory this has always been wrong, but we've only seen actual bugs
manifesting in 8.0 with the other multiqueue-related changes. So I think
it's safe to skip them for 7.2.

The bug fixed by the previous patch (bdrv_activate()) might not even
theoretically be a problem while bdrv_co_activate() didn't exist, though
I haven't investigated this in detail.

Kevin