[Qemu-devel] Re: [PATCH 2/2] Add flush=off parameter to -drive

[Kevin Wolf <kwolf@redhat.com>]

Am 10.05.2010 23:51, schrieb Alexander Graf:
> Usually the guest can tell the host to flush data to disk. In some cases we
> don't want to flush though, but try to keep everything in cache.
> 
> So let's add a new parameter to -drive that allows us to set the flushing
> behavior to "on" or "off", defaulting to enabling the guest to flush.
> 
> Signed-off-by: Alexander Graf <agraf@suse.de>

What about another cache=... value instead of adding more options? I'm
quite sure you'll only ever need this with writeback caching. So we
could have cache=none|writethrough|writeback|wb-noflush or something
like that.

> ---
>  block/raw-posix.c |   13 +++++++++++++

This is obviously wrong. If you want to introduce new behaviour to the
block layer, you must do it consistently and not just for one block
driver. So these changes should be made to the generic functions in
block.c instead.

Kevin