fs/adfs: bigdir: calculate and validate directory checkbyte

	return 0;

}

static u8 adfs_fplus_checkbyte(struct adfs_dir *dir)

{

	struct adfs_bigdirheader *h = dir->bighead;

	struct adfs_bigdirtail *t = dir->bigtail;

	unsigned int end, bs, bi, i;

	__le32 *bp;

	u32 dircheck;

	end = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries)) +

		le32_to_cpu(h->bigdirnamesize);

	/* Accumulate the contents of the header, entries and names */

	for (dircheck = 0, bi = 0; end; bi++) {

		bp = (void *)dir->bhs[bi]->b_data;

		bs = dir->bhs[bi]->b_size;

		if (bs > end)

			bs = end;

		for (i = 0; i < bs; i += sizeof(u32))

			dircheck = ror32(dircheck, 13) ^ le32_to_cpup(bp++);

		end -= bs;

	}

	/* Accumulate the contents of the tail except for the check byte */

	dircheck = ror32(dircheck, 13) ^ le32_to_cpu(t->bigdirendname);

	dircheck = ror32(dircheck, 13) ^ t->bigdirendmasseq;

	dircheck = ror32(dircheck, 13) ^ t->reserved[0];

	dircheck = ror32(dircheck, 13) ^ t->reserved[1];

	return dircheck ^ dircheck >> 8 ^ dircheck >> 16 ^ dircheck >> 24;

}

static int adfs_fplus_read(struct super_block *sb, u32 indaddr,

			   unsigned int size, struct adfs_dir *dir)

{

		goto out;

	}

	if (adfs_fplus_checkbyte(dir) != t->bigdircheckbyte) {

		adfs_error(sb, "dir %06x checkbyte mismatch\n", indaddr);

		goto out;

	}

	dir->parent_id = le32_to_cpu(h->bigdirparent);

	return 0;