Re: [Qemu-devel] [PATCH 00/15] block: AioContext management, part 2

[Kevin Wolf <kwolf@redhat.com>]

Am 23.05.2019 um 18:00 hat Kevin Wolf geschrieben:
> Recently, a few bugs were reported that resulted from an inconsistent
> state regarding AioContexts. Block nodes can end up in different
> contexts than their users expect - the AioContext of a node can even
> change under the feet of a device with no way for the device to forbid
> this. We recently added a few basic checks to scsi-disk and virtio-blk,
> but they are by far not enough.
> 
> Part 1 solved the first half of the problem and made sure that
> AioContext changes are propagated through the graph as necessary, so
> that a bdrv_set_aio_context() correctly pulls everything that uses the
> node into the right context.
> 
> This is part 2 that fixes the second half: Attaching new child nodes
> where the parent and child are already in different AioContexts. This
> operation may only succeed if we can move one of the node into the
> context of the other node.
> 
> After applying this series, unchecked bdrv_set_aio_context() doesn't
> exist any more and all users call functions that make sure that the
> AioContext assignments across the graph stays consistent.

Applied to the block branch.

Kevin