xfs: cleanup xfs_getfsmap_rtdev_rtbitmap

Use mp->m_sb.sb_rblocks to calculate the end instead of sb_rextents that
needs a conversion, use consistent names to xfs_rtblock_t types, and
only calculated them by the time they are needed.  Remove the pointless
"high" local variable that only has a single user.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

Author: Christoph Hellwig

fs/xfs/xfs_fsmap.c

@@ -754,40 +754,39 @@ xfs_getfsmap_rtdev_rtbitmap(
 
 	struct xfs_rtalloc_rec		ahigh = { 0 };
 	struct xfs_mount		*mp = tp->t_mountp;
-	xfs_rtblock_t			start_rtb;
-	xfs_rtblock_t			end_rtb;
-	xfs_rtxnum_t			high;
+	xfs_rtblock_t			start_rtbno, end_rtbno;
 	uint64_t			eofs;
 	int				error;
 
-	eofs = XFS_FSB_TO_BB(mp, xfs_rtx_to_rtb(mp, mp->m_sb.sb_rextents));
+	eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
 	if (keys[0].fmr_physical >= eofs)
 		return 0;
-	start_rtb = XFS_BB_TO_FSBT(mp,
-				keys[0].fmr_physical + keys[0].fmr_length);
-	end_rtb = XFS_BB_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
 
 	info->missing_owner = XFS_FMR_OWN_UNKNOWN;
 
 	/* Adjust the low key if we are continuing from where we left off. */
+	start_rtbno = xfs_daddr_to_rtb(mp,
+			keys[0].fmr_physical + keys[0].fmr_length);
 	if (keys[0].fmr_length > 0) {
-		info->low_daddr = xfs_rtb_to_daddr(mp, start_rtb);
+		info->low_daddr = xfs_rtb_to_daddr(mp, start_rtbno);
 		if (info->low_daddr >= eofs)
 			return 0;
 	}
 
-	trace_xfs_fsmap_low_linear_key(mp, info->dev, start_rtb);
-	trace_xfs_fsmap_high_linear_key(mp, info->dev, end_rtb);
+	end_rtbno = xfs_daddr_to_rtb(mp, min(eofs - 1, keys[1].fmr_physical));
+
+	trace_xfs_fsmap_low_linear_key(mp, info->dev, start_rtbno);
+	trace_xfs_fsmap_high_linear_key(mp, info->dev, end_rtbno);
 
 	xfs_rtbitmap_lock_shared(mp, XFS_RBMLOCK_BITMAP);
 
 	/*
 	 * Set up query parameters to return free rtextents covering the range
 	 * we want.
 	 */
-	high = xfs_rtb_to_rtxup(mp, end_rtb);
-	error = xfs_rtalloc_query_range(mp, tp, xfs_rtb_to_rtx(mp, start_rtb),
-			high, xfs_getfsmap_rtdev_rtbitmap_helper, info);
+	error = xfs_rtalloc_query_range(mp, tp, xfs_rtb_to_rtx(mp, start_rtbno),
+			xfs_rtb_to_rtxup(mp, end_rtbno),
+			xfs_getfsmap_rtdev_rtbitmap_helper, info);
 	if (error)
 		goto err;