[sheepdog] [PATCH v2 0/4] add support for object cache test

[Liu Yuan]

On Tue, Aug 13, 2013 at 01:37:36PM +0900, MORITA Kazutaka wrote:
> From: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
> 
> v2:
>  - rebased onto the devel branch
>  - added necessary flush after _vdi_write()
>  - call _filter_qemu_io() in _qemu_io()
> 
> This series enables us to test object cache by running the following
> commands.
> 
>  # SHEEP_EXTRA_OPTIONS="-w size=100" ./check
>  # SHEEP_EXTRA_OPTIONS="-w size=100" ./check -writethrough
>  # SHEEP_EXTRA_OPTIONS="-w size=100" ./check -direct

our vdi read/write causes many false alarms because 
 - write -w doesn't flush the cache
 - read doesn't release the cache

Maybe we should use qemu-io which release the cache and support vected io,
to replace all the 'vdi write/read'.

'SHEEP_EXTRA_OPTIONS="-w size=100" ./check' is cumbersome.

./check -writeback is better. I think we only need to test writeback. direct
and writethrough only need one test script to test functionality because
writethrough is pretty much the same as writeback, and direct is same as no
cache.

Thanks
Yuan