LU-10565 osd: unify interface for vfs

LU-10565 osd: unify interface for vfs

Some vfs changes were applied to other part but
OSD. So unify them with OSD layer.

Lustre-change: https://review.whamcloud.com/31646
Lustre-commit: 55ed739f7efb7029b02fe50999547f9aac40af72

Signed-off-by: Yang Sheng <yang.sheng@intel.com>
Change-Id: Ia3e907964d6321571f52e4c24a46a8ab64e4d056
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Wang Shilong <wshilong@ddn.com>
Reviewed-on: https://review.whamcloud.com/33991
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Wang Shilong <wshilong@whamcloud.com>