diff --git a/include/linux/ext2_fs.h b/include/linux/ext2_fs.h
index f28dba5..5f65ec7 100644
--- a/include/linux/ext2_fs.h
+++ b/include/linux/ext2_fs.h
@@ -536,4 +536,26 @@
 					 ~EXT2_DIR_ROUND)
 #define EXT2_MAX_REC_LEN		((1<<16)-1)
 
+#define EXT2_SB_MAGIC_OFFSET	0x38
+#define EXT2_SB_BLOCKS_OFFSET	0x04
+#define EXT2_SB_BSIZE_OFFSET	0x18
+
+static inline u64 ext2_image_size(void *ext2_sb)
+{
+	__u8 *p = ext2_sb;
+	if (*(__le16 *)(p + EXT2_SB_MAGIC_OFFSET) != cpu_to_le16(EXT2_SUPER_MAGIC))
+		return 0;
+	return (u64)le32_to_cpup((__le32 *)(p + EXT2_SB_BLOCKS_OFFSET)) <<
+		le32_to_cpup((__le32 *)(p + EXT2_SB_BSIZE_OFFSET));
+}
+
+static inline void verify_offsets(void)
+{
+#define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y));
+	A(EXT2_SB_MAGIC_OFFSET, s_magic);
+	A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count);
+	A(EXT2_SB_BSIZE_OFFSET, s_log_block_size);
+#undef A
+}
+
 #endif	/* _LINUX_EXT2_FS_H */