EXTENT_BUFFER_TREE_REF
if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {