+int nilfs_check_feature_compatibility(struct super_block *sb,
+ struct nilfs_super_block *sbp)
+{
+ __u64 features;
+
+ features = le64_to_cpu(sbp->s_feature_incompat) &
+ ~NILFS_FEATURE_INCOMPAT_SUPP;
+ if (features) {
+ printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
+ "optional features (%llx)\n",
+ (unsigned long long)features);
+ return -EINVAL;
+ }
+ features = le64_to_cpu(sbp->s_feature_compat_ro) &
+ ~NILFS_FEATURE_COMPAT_RO_SUPP;
+ if (!(sb->s_flags & MS_RDONLY) && features) {
+ printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
+ "unsupported optional features (%llx)\n",
+ (unsigned long long)features);
+ return -EINVAL;
+ }
+ return 0;
+}
+