bcachefs: Improve btree_key_cache_flush_pos()

btree_key_cache_flush_pos() uses BTREE_ITER_CACHED_NOFILL - but it
wasn't checking for !ck->valid. It does check for the entry being dirty,
so it shouldn't matter, but this refactor it a bit and adds and
assertion.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
1 file changed