ext4_es_must_keep
if (!ext4_es_must_keep(&newes))
if (ext4_es_must_keep(es))
if (!ext4_es_must_keep(es)) {
if (!ext4_es_must_keep(es)) {
if (!ext4_es_must_keep(es)) {
if (err2 == -ENOMEM && !ext4_es_must_keep(&newes))