vfs: add RENAME_WHITEOUT

This adds a new RENAME_WHITEOUT flag.  This flag makes rename() create a
whiteout of source.  The whiteout creation is atomic relative to the
rename.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
(cherry picked from commit 0d7a855526dd672e114aff2ac22b60fc6f155b08)
Signed-off-by: Alex Shi <alex.shi@linaro.org>
2 files changed