xfs: improve the code that checks recovered rmap intent items

The code that validates recovered rmap intent items is kind of a mess --
it doesn't use the standard xfs type validators, and it doesn't check
for things that it should.  Fix the validator function to use the
standard validation helpers and look for more types of obvious errors.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/xfs_rmap_item.c

@@ -466,11 +466,9 @@ xfs_rui_validate_map(
 	struct xfs_mount		*mp,
 	struct xfs_map_extent		*rmap)
 {
-	xfs_fsblock_t			startblock_fsb;
-	bool				op_ok;
+	if (rmap->me_flags & ~XFS_RMAP_EXTENT_FLAGS)
+		return false;
 
-	startblock_fsb = XFS_BB_TO_FSB(mp,
-			   XFS_FSB_TO_DADDR(mp, rmap->me_startblock));
 	switch (rmap->me_flags & XFS_RMAP_EXTENT_TYPE_MASK) {
 	case XFS_RMAP_EXTENT_MAP:
 	case XFS_RMAP_EXTENT_MAP_SHARED:
@@ -480,17 +478,25 @@ xfs_rui_validate_map(
 	case XFS_RMAP_EXTENT_CONVERT_SHARED:
 	case XFS_RMAP_EXTENT_ALLOC:
 	case XFS_RMAP_EXTENT_FREE:
-		op_ok = true;
 		break;
 	default:
-		op_ok = false;
-		break;
+		return false;
 	}
-	if (!op_ok || startblock_fsb == 0 ||
-	    rmap->me_len == 0 ||
-	    startblock_fsb >= mp->m_sb.sb_dblocks ||
-	    rmap->me_len >= mp->m_sb.sb_agblocks ||
-	    (rmap->me_flags & ~XFS_RMAP_EXTENT_FLAGS))
+
+	if (!XFS_RMAP_NON_INODE_OWNER(rmap->me_owner) &&
+	    !xfs_verify_ino(mp, rmap->me_owner))
+		return false;
+
+	if (rmap->me_startoff + rmap->me_len <= rmap->me_startoff)
+		return false;
+
+	if (rmap->me_startblock + rmap->me_len <= rmap->me_startblock)
+		return false;
+
+	if (!xfs_verify_fsbno(mp, rmap->me_startblock))
+		return false;
+
+	if (!xfs_verify_fsbno(mp, rmap->me_startblock + rmap->me_len - 1))
 		return false;
 
 	return true;