diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index 4e7be6b4ca8e..8f6a05db4468 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -923,16 +923,41 @@ xfs_growfs_rt(
 	uint8_t		*rsum_cache;	/* old summary cache */
 
 	sbp = &mp->m_sb;
-	/*
-	 * Initial error checking.
-	 */
+
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
-	if (mp->m_rtdev_targp == NULL || mp->m_rbmip == NULL ||
-	    (nrblocks = in->newblocks) <= sbp->sb_rblocks ||
-	    (sbp->sb_rblocks && (in->extsize != sbp->sb_rextsize)))
+
+	/* Needs to have been mounted with an rt device. */
+	if (!XFS_IS_REALTIME_MOUNT(mp))
 		return -EINVAL;
-	if ((error = xfs_sb_validate_fsb_count(sbp, nrblocks)))
+	/*
+	 * Mount should fail if the rt bitmap/summary files don't load, but
+	 * we'll check anyway.
+	 */
+	if (!mp->m_rbmip || !mp->m_rsumip)
+		return -EINVAL;
+
+	/* Shrink not supported. */
+	if (in->newblocks <= sbp->sb_rblocks)
+		return -EINVAL;
+
+	/* Can only change rt extent size when adding rt volume. */
+	if (sbp->sb_rblocks > 0 && in->extsize != sbp->sb_rextsize)
+		return -EINVAL;
+
+	/* Range check the extent size. */
+	if (XFS_FSB_TO_B(mp, in->extsize) > XFS_MAX_RTEXTSIZE ||
+	    XFS_FSB_TO_B(mp, in->extsize) < XFS_MIN_RTEXTSIZE)
+		return -EINVAL;
+
+	/* Unsupported realtime features. */
+	if (xfs_sb_version_hasrmapbt(&mp->m_sb) ||
+	    xfs_sb_version_hasreflink(&mp->m_sb))
+		return -EOPNOTSUPP;
+
+	nrblocks = in->newblocks;
+	error = xfs_sb_validate_fsb_count(sbp, nrblocks);
+	if (error)
 		return error;
 	/*
 	 * Read in the last block of the device, make sure it exists.