xfs: strengthen rtalloc query range checks

Strengthen the rtalloc range query checks to make sure that the keys do
not run off the end of the realtime device inappropriately.  Note that
the query range functions require units of rt extents, not blocks,
despite the type name.
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

@@ -1038,8 +1038,11 @@ xfs_rtalloc_query_range(
 
 	if (low_rec->ar_startblock > high_rec->ar_startblock)
 		return -EINVAL;
-	else if (low_rec->ar_startblock == high_rec->ar_startblock)
+	if (low_rec->ar_startblock >= mp->m_sb.sb_rextents ||
+	    low_rec->ar_startblock == high_rec->ar_startblock)
 		return 0;
+	if (high_rec->ar_startblock >= mp->m_sb.sb_rextents)
+		high_rec->ar_startblock = mp->m_sb.sb_rextents - 1;
 
 	/* Iterate the bitmap, looking for discrepancies. */
 	rtstart = low_rec->ar_startblock;
@@ -1083,7 +1086,7 @@ 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_rblocks;
+	keys[1].ar_startblock = tp->t_mountp->m_sb.sb_rextents - 1;
 	keys[0].ar_blockcount = keys[1].ar_blockcount = 0;
 
 	return xfs_rtalloc_query_range(tp, &keys[0], &keys[1], fn, priv);