+/* somewhat more expensive than our other checks, so use sparingly. */
+static int ocfs2_check_group_descriptor(struct super_block *sb,
+ struct ocfs2_dinode *di,
+ struct ocfs2_group_desc *gd)
+{
+ unsigned int max_bits;
+
+ if (!OCFS2_IS_VALID_GROUP_DESC(gd)) {
+ OCFS2_RO_ON_INVALID_GROUP_DESC(sb, gd);
+ return -EIO;
+ }
+
+ if (di->i_blkno != gd->bg_parent_dinode) {
+ ocfs2_error(sb, "Group descriptor # %llu has bad parent "
+ "pointer (%llu, expected %llu)",
+ (unsigned long long)le64_to_cpu(gd->bg_blkno),
+ (unsigned long long)le64_to_cpu(gd->bg_parent_dinode),
+ (unsigned long long)le64_to_cpu(di->i_blkno));
+ return -EIO;
+ }
+
+ max_bits = le16_to_cpu(di->id2.i_chain.cl_cpg) * le16_to_cpu(di->id2.i_chain.cl_bpc);
+ if (le16_to_cpu(gd->bg_bits) > max_bits) {
+ ocfs2_error(sb, "Group descriptor # %llu has bit count of %u",
+ (unsigned long long)le64_to_cpu(gd->bg_blkno),
+ le16_to_cpu(gd->bg_bits));
+ return -EIO;
+ }
+
+ if (le16_to_cpu(gd->bg_chain) >=
+ le16_to_cpu(di->id2.i_chain.cl_next_free_rec)) {
+ ocfs2_error(sb, "Group descriptor # %llu has bad chain %u",
+ (unsigned long long)le64_to_cpu(gd->bg_blkno),
+ le16_to_cpu(gd->bg_chain));
+ return -EIO;
+ }
+
+ if (le16_to_cpu(gd->bg_free_bits_count) > le16_to_cpu(gd->bg_bits)) {
+ ocfs2_error(sb, "Group descriptor # %llu has bit count %u but "
+ "claims that %u are free",
+ (unsigned long long)le64_to_cpu(gd->bg_blkno),
+ le16_to_cpu(gd->bg_bits),
+ le16_to_cpu(gd->bg_free_bits_count));
+ return -EIO;
+ }
+
+ if (le16_to_cpu(gd->bg_bits) > (8 * le16_to_cpu(gd->bg_size))) {
+ ocfs2_error(sb, "Group descriptor # %llu has bit count %u but "
+ "max bitmap bits of %u",
+ (unsigned long long)le64_to_cpu(gd->bg_blkno),
+ le16_to_cpu(gd->bg_bits),
+ 8 * le16_to_cpu(gd->bg_size));
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int ocfs2_block_group_fill(handle_t *handle,