xfs: fix xfs_rtalloc_rec units

All the realtime allocation functions deal with space on the rtdev in
units of realtime extents.  However, struct xfs_rtalloc_rec confusingly
uses the word 'block' in the name, even though they're really extents.

Fix the naming problem and fix all the unit handling problems in the two
existing users.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>

fs/xfs/libxfs/xfs_rtbitmap.c

@@ -1036,17 +1036,17 @@ xfs_rtalloc_query_range(
 	int				is_free;
 	int				error = 0;
 
-	if (low_rec->ar_startblock > high_rec->ar_startblock)
+	if (low_rec->ar_startext > high_rec->ar_startext)
 		return -EINVAL;
-	if (low_rec->ar_startblock >= mp->m_sb.sb_rextents ||
-	    low_rec->ar_startblock == high_rec->ar_startblock)
+	if (low_rec->ar_startext >= mp->m_sb.sb_rextents ||
+	    low_rec->ar_startext == high_rec->ar_startext)
 		return 0;
-	if (high_rec->ar_startblock >= mp->m_sb.sb_rextents)
-		high_rec->ar_startblock = mp->m_sb.sb_rextents - 1;
+	if (high_rec->ar_startext >= mp->m_sb.sb_rextents)
+		high_rec->ar_startext = mp->m_sb.sb_rextents - 1;
 
 	/* Iterate the bitmap, looking for discrepancies. */
-	rtstart = low_rec->ar_startblock;
-	rem = high_rec->ar_startblock - rtstart;
+	rtstart = low_rec->ar_startext;
+	rem = high_rec->ar_startext - rtstart;
 	while (rem) {
 		/* Is the first block free? */
 		error = xfs_rtcheck_range(mp, tp, rtstart, 1, 1, &rtend,
@@ -1056,13 +1056,13 @@ xfs_rtalloc_query_range(
 
 		/* How long does the extent go for? */
 		error = xfs_rtfind_forw(mp, tp, rtstart,
-				high_rec->ar_startblock - 1, &rtend);
+				high_rec->ar_startext - 1, &rtend);
 		if (error)
 			break;
 
 		if (is_free) {
-			rec.ar_startblock = rtstart;
-			rec.ar_blockcount = rtend - rtstart + 1;
+			rec.ar_startext = rtstart;
+			rec.ar_extcount = rtend - rtstart + 1;
 
 			error = fn(tp, &rec, priv);
 			if (error)
@@ -1085,9 +1085,9 @@ xfs_rtalloc_query_all(
 {
 	struct xfs_rtalloc_rec		keys[2];
 
-	keys[0].ar_startblock = 0;
-	keys[1].ar_startblock = tp->t_mountp->m_sb.sb_rextents - 1;
-	keys[0].ar_blockcount = keys[1].ar_blockcount = 0;
+	keys[0].ar_startext = 0;
+	keys[1].ar_startext = tp->t_mountp->m_sb.sb_rextents - 1;
+	keys[0].ar_extcount = keys[1].ar_extcount = 0;
 
 	return xfs_rtalloc_query_range(tp, &keys[0], &keys[1], fn, priv);
 }

fs/xfs/scrub/rtbitmap.c

@@ -66,11 +66,15 @@ xfs_scrub_rtbitmap_rec(
 	void				*priv)
 {
 	struct xfs_scrub_context	*sc = priv;
+	xfs_rtblock_t			startblock;
+	xfs_rtblock_t			blockcount;
 
-	if (rec->ar_startblock + rec->ar_blockcount <= rec->ar_startblock ||
-	    !xfs_verify_rtbno(sc->mp, rec->ar_startblock) ||
-	    !xfs_verify_rtbno(sc->mp, rec->ar_startblock +
-			rec->ar_blockcount - 1))
+	startblock = rec->ar_startext * tp->t_mountp->m_sb.sb_rextsize;
+	blockcount = rec->ar_extcount * tp->t_mountp->m_sb.sb_rextsize;
+
+	if (startblock + blockcount <= startblock ||
+	    !xfs_verify_rtbno(sc->mp, startblock) ||
+	    !xfs_verify_rtbno(sc->mp, startblock + blockcount - 1))
 		xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
 	return 0;
 }
@@ -139,14 +143,23 @@ xfs_scrub_xref_is_used_rt_space(
 	xfs_rtblock_t			fsbno,
 	xfs_extlen_t			len)
 {
+	xfs_rtblock_t			startext;
+	xfs_rtblock_t			endext;
+	xfs_rtblock_t			extcount;
 	bool				is_free;
 	int				error;
 
 	if (xfs_scrub_skip_xref(sc->sm))
 		return;
 
+	startext = fsbno;
+	endext = fsbno + len - 1;
+	do_div(startext, sc->mp->m_sb.sb_rextsize);
+	if (do_div(endext, sc->mp->m_sb.sb_rextsize))
+		endext++;
+	extcount = endext - startext;
 	xfs_ilock(sc->mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
-	error = xfs_rtalloc_extent_is_free(sc->mp, sc->tp, fsbno, len,
+	error = xfs_rtalloc_extent_is_free(sc->mp, sc->tp, startext, extcount,
 			&is_free);
 	if (!xfs_scrub_should_check_xref(sc, &error, NULL))
 		goto out_unlock;

fs/xfs/xfs_fsmap.c

@@ -465,10 +465,9 @@ xfs_getfsmap_rtdev_rtbitmap_helper(
 	struct xfs_rmap_irec		irec;
 	xfs_daddr_t			rec_daddr;
 
-	rec_daddr = XFS_FSB_TO_BB(mp, rec->ar_startblock);
-
-	irec.rm_startblock = rec->ar_startblock;
-	irec.rm_blockcount = rec->ar_blockcount;
+	irec.rm_startblock = rec->ar_startext * mp->m_sb.sb_rextsize;
+	rec_daddr = XFS_FSB_TO_BB(mp, irec.rm_startblock);
+	irec.rm_blockcount = rec->ar_extcount * mp->m_sb.sb_rextsize;
 	irec.rm_owner = XFS_RMAP_OWN_NULL;	/* "free" */
 	irec.rm_offset = 0;
 	irec.rm_flags = 0;
@@ -534,8 +533,11 @@ xfs_getfsmap_rtdev_rtbitmap_query(
 
 	xfs_ilock(tp->t_mountp->m_rbmip, XFS_ILOCK_SHARED);
 
-	alow.ar_startblock = info->low.rm_startblock;
-	ahigh.ar_startblock = info->high.rm_startblock;
+	alow.ar_startext = info->low.rm_startblock;
+	ahigh.ar_startext = info->high.rm_startblock;
+	do_div(alow.ar_startext, tp->t_mountp->m_sb.sb_rextsize);
+	if (do_div(ahigh.ar_startext, tp->t_mountp->m_sb.sb_rextsize))
+		ahigh.ar_startext++;
 	error = xfs_rtalloc_query_range(tp, &alow, &ahigh,
 			xfs_getfsmap_rtdev_rtbitmap_helper, info);
 	if (error)

fs/xfs/xfs_rtalloc.h

@@ -23,9 +23,14 @@
 struct xfs_mount;
 struct xfs_trans;
 
+/*
+ * XXX: Most of the realtime allocation functions deal in units of realtime
+ * extents, not realtime blocks.  This looks funny when paired with the type
+ * name and screams for a larger cleanup.
+ */
 struct xfs_rtalloc_rec {
-	xfs_rtblock_t		ar_startblock;
-	xfs_rtblock_t		ar_blockcount;
+	xfs_rtblock_t		ar_startext;
+	xfs_rtblock_t		ar_extcount;
 };
 
 typedef int (*xfs_rtalloc_query_range_fn)(