+#define XFS_FIBT_BLOCK(mp) ((xfs_agblock_t)(XFS_IBT_BLOCK(mp) + 1))
+
+/*
+ * The first data block of an AG depends on whether the filesystem was formatted
+ * with the finobt feature. If so, account for the finobt reserved root btree
+ * block.
+ */
+#define XFS_PREALLOC_BLOCKS(mp) \
+ (xfs_sb_version_hasfinobt(&((mp)->m_sb)) ? \
+ XFS_FIBT_BLOCK(mp) + 1 : \
+ XFS_IBT_BLOCK(mp) + 1)