[sheepdog] [PATCH v5] sheepdog: add discard/trim support for sheepdog

[MORITA Kazutaka]

At Tue, 16 Apr 2013 00:15:04 +0800,
Liu Yuan wrote:
> 
> From: Liu Yuan <tailai.ly at taobao.com>
> 
> The 'TRIM' command from VM that is to release underlying data storage for
> better thin-provision is already supported by the Sheepdog.
> 
> This patch adds the TRIM support at QEMU part.
> 
> For older Sheepdog that doesn't support it, we return 0(success) to upper layer.
> 
> Cc: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
> Cc: Kevin Wolf <kwolf at redhat.com>
> Cc: Stefan Hajnoczi <stefanha at redhat.com>
> Cc: Paolo Bonzini <pbonzini at redhat.com>
> Signed-off-by: Liu Yuan <tailai.ly at taobao.com>
> ---
> v5:
>  - adjust macro numbering
> v4:
>  - adjust discard macro
>  - return success when operation is not supported by sheep
>  - add coroutine_fn marker
> v3:
>  - fix a silly accidental deletion of 'default' in switch clause.
> v2:
>  - skip the object when it is not allocated
> 
>  block/sheepdog.c |   56 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 55 insertions(+), 1 deletion(-)

Reviewed-by: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>