diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index 588d44613094..443cf33f6666 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -679,7 +679,7 @@ xfs_ialloc_ag_alloc(
 		args.minalignslop = igeo->cluster_align - 1;
 
 		/* Allow space for the inode btree to split. */
-		args.minleft = igeo->inobt_maxlevels - 1;
+		args.minleft = igeo->inobt_maxlevels;
 		if ((error = xfs_alloc_vextent(&args)))
 			return error;
 
@@ -727,7 +727,7 @@ xfs_ialloc_ag_alloc(
 		/*
 		 * Allow space for the inode btree to split.
 		 */
-		args.minleft = igeo->inobt_maxlevels - 1;
+		args.minleft = igeo->inobt_maxlevels;
 		if ((error = xfs_alloc_vextent(&args)))
 			return error;
 	}
diff --git a/fs/xfs/libxfs/xfs_trans_space.h b/fs/xfs/libxfs/xfs_trans_space.h
index c6df01a2a158..7ad3659c5d2a 100644
--- a/fs/xfs/libxfs/xfs_trans_space.h
+++ b/fs/xfs/libxfs/xfs_trans_space.h
@@ -58,7 +58,7 @@
 #define	XFS_IALLOC_SPACE_RES(mp)	\
 	(M_IGEO(mp)->ialloc_blks + \
 	 ((xfs_sb_version_hasfinobt(&mp->m_sb) ? 2 : 1) * \
-	  (M_IGEO(mp)->inobt_maxlevels - 1)))
+	  M_IGEO(mp)->inobt_maxlevels))
 
 /*
  * Space reservation values for various transactions.