diff --git a/db/block.c b/db/block.c
index b50b2c16060ac7..f197e10cd5a08d 100644
--- a/db/block.c
+++ b/db/block.c
@@ -423,7 +423,7 @@ rtextent_f(
 		return 0;
 	}
 
-	rtbno = xfs_rtx_to_rtb(mp, rtx);
+	rtbno = xfs_rtbxlen_to_blen(mp, rtx);
 	ASSERT(typtab[TYP_DATA].typnm == TYP_DATA);
 	set_rt_cur(&typtab[TYP_DATA], xfs_rtb_to_daddr(mp, rtbno),
 			mp->m_sb.sb_rextsize * blkbb, DB_RING_ADD, NULL);
diff --git a/libxfs/xfs_bmap.c b/libxfs/xfs_bmap.c
index cebf5479189280..48b05c40e23235 100644
--- a/libxfs/xfs_bmap.c
+++ b/libxfs/xfs_bmap.c
@@ -4088,7 +4088,7 @@ xfs_bmapi_reserve_delalloc(
 
 	fdblocks = indlen;
 	if (XFS_IS_REALTIME_INODE(ip)) {
-		error = xfs_dec_frextents(mp, xfs_rtb_to_rtx(mp, alen));
+		error = xfs_dec_frextents(mp, xfs_blen_to_rtbxlen(mp, alen));
 		if (error)
 			goto out_unreserve_quota;
 	} else {
@@ -4123,7 +4123,7 @@ xfs_bmapi_reserve_delalloc(
 
 out_unreserve_frextents:
 	if (XFS_IS_REALTIME_INODE(ip))
-		xfs_add_frextents(mp, xfs_rtb_to_rtx(mp, alen));
+		xfs_add_frextents(mp, xfs_blen_to_rtbxlen(mp, alen));
 out_unreserve_quota:
 	if (XFS_IS_QUOTA_ON(mp))
 		xfs_quota_unreserve_blkres(ip, alen);
@@ -5031,7 +5031,7 @@ xfs_bmap_del_extent_delay(
 	fdblocks = da_diff;
 
 	if (isrt)
-		xfs_add_frextents(mp, xfs_rtb_to_rtx(mp, del->br_blockcount));
+		xfs_add_frextents(mp, xfs_blen_to_rtbxlen(mp, del->br_blockcount));
 	else
 		fdblocks += del->br_blockcount;
 
diff --git a/libxfs/xfs_rtbitmap.h b/libxfs/xfs_rtbitmap.h
index 776cca9e41bf05..b2b9e59a87a278 100644
--- a/libxfs/xfs_rtbitmap.h
+++ b/libxfs/xfs_rtbitmap.h
@@ -22,13 +22,37 @@ struct xfs_rtalloc_args {
 
 static inline xfs_rtblock_t
 xfs_rtx_to_rtb(
-	struct xfs_mount	*mp,
+	struct xfs_rtgroup	*rtg,
 	xfs_rtxnum_t		rtx)
+{
+	struct xfs_mount	*mp = rtg_mount(rtg);
+	xfs_rtblock_t		start = xfs_rgno_start_rtb(mp, rtg_rgno(rtg));
+
+	if (mp->m_rtxblklog >= 0)
+		return start + (rtx << mp->m_rtxblklog);
+	return start + (rtx * mp->m_sb.sb_rextsize);
+}
+
+/* Convert an rgbno into an rt extent number. */
+static inline xfs_rtxnum_t
+xfs_rgbno_to_rtx(
+	struct xfs_mount	*mp,
+	xfs_rgblock_t		rgbno)
+{
+	if (likely(mp->m_rtxblklog >= 0))
+		return rgbno >> mp->m_rtxblklog;
+	return rgbno / mp->m_sb.sb_rextsize;
+}
+
+static inline uint64_t
+xfs_rtbxlen_to_blen(
+	struct xfs_mount	*mp,
+	xfs_rtbxlen_t		rtbxlen)
 {
 	if (mp->m_rtxblklog >= 0)
-		return rtx << mp->m_rtxblklog;
+		return rtbxlen << mp->m_rtxblklog;
 
-	return rtx * mp->m_sb.sb_rextsize;
+	return rtbxlen * mp->m_sb.sb_rextsize;
 }
 
 static inline xfs_extlen_t
@@ -65,16 +89,29 @@ xfs_extlen_to_rtxlen(
 	return len / mp->m_sb.sb_rextsize;
 }
 
+/* Convert an rt block count into an rt extent count. */
+static inline xfs_rtbxlen_t
+xfs_blen_to_rtbxlen(
+	struct xfs_mount	*mp,
+	uint64_t		blen)
+{
+	if (likely(mp->m_rtxblklog >= 0))
+		return blen >> mp->m_rtxblklog;
+
+	return div_u64(blen, mp->m_sb.sb_rextsize);
+}
+
 /* Convert an rt block number into an rt extent number. */
 static inline xfs_rtxnum_t
 xfs_rtb_to_rtx(
 	struct xfs_mount	*mp,
 	xfs_rtblock_t		rtbno)
 {
-	if (likely(mp->m_rtxblklog >= 0))
-		return rtbno >> mp->m_rtxblklog;
+	uint64_t		__rgbno = __xfs_rtb_to_rgbno(mp, rtbno);
 
-	return div_u64(rtbno, mp->m_sb.sb_rextsize);
+	if (likely(mp->m_rtxblklog >= 0))
+		return __rgbno >> mp->m_rtxblklog;
+	return div_u64(__rgbno, mp->m_sb.sb_rextsize);
 }
 
 /* Return the offset of an rt block number within an rt extent. */
@@ -89,26 +126,6 @@ xfs_rtb_to_rtxoff(
 	return do_div(rtbno, mp->m_sb.sb_rextsize);
 }
 
-/*
- * Convert an rt block number into an rt extent number, rounding up to the next
- * rt extent if the rt block is not aligned to an rt extent boundary.
- */
-static inline xfs_rtxnum_t
-xfs_rtb_to_rtxup(
-	struct xfs_mount	*mp,
-	xfs_rtblock_t		rtbno)
-{
-	if (likely(mp->m_rtxblklog >= 0)) {
-		if (rtbno & mp->m_rtxblkmask)
-			return (rtbno >> mp->m_rtxblklog) + 1;
-		return rtbno >> mp->m_rtxblklog;
-	}
-
-	if (do_div(rtbno, mp->m_sb.sb_rextsize))
-		rtbno++;
-	return rtbno;
-}
-
 /* Round this rtblock up to the nearest rt extent size. */
 static inline xfs_rtblock_t
 xfs_rtb_roundup_rtx(
