EXTENT_BUFFER_WRITE_ERR
set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
if (unlikely(test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)))
if (test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))