BLOCK_GROUP_FLAG_TO_COPY
set_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags);
clear_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags);
if (!test_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags)) {
ret = test_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags);