Re: [Qemu-devel] [PATCH 1/3] block: Support streaming to an intermediate layer

[Kevin Wolf]

Am 20.02.2015 um 14:53 hat Alberto Garcia geschrieben:
> This adds a new 'top' parameter to stream_start(), that specifies the
> block device where the data will be written. The image is changed to
> read-write mode during the streaming and back to read-only afterwards.
> 
> This also unblocks the stream operation in backing files.
> 
> Signed-off-by: Alberto Garcia <address@hidden>

The bs parameter is now only used for the following things:

1. As the default for top

2. For error handling: Any errors are reported for bs, even though they
   are actually for top. Is this correct behaviour? It looks
   questionable to me.

3. As the BDS that owns the job

My question is whether we can't simply call stream_start() with an
intermediate node as bs instead of introducing a new parameter. I'm not
completely sure about the consequences of 3., i.e. moving ownership of a
block job to some BDS somewhere down the chain, but otherwise it should
be possible and seems cleaner.

Kevin