raw-posix: Implement .bdrv_co_preadv/pwritev
The raw-posix block driver actually supports byte-aligned requests now on non-O_DIRECT images, like it already (and previously incorrectly) claimed in bs->request_alignment. For some block drivers this means that a RMW cycle can be avoided when they write sub-sector metadata e.g. for cluster allocation. Signed-off-by: NKevin Wolf <kwolf@redhat.com> Reviewed-by: NEric Blake <eblake@redhat.com> Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Showing
想要评论请 注册 或 登录