[PATCH 7/9] xfs: do not do pointer arithmetics on extent records

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

We need to call xfs_iext_get_ext for the previous extent to get a valid
pointer, and can't just do pointer arithmetics as they might be in
different pages.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>

Index: xfs/fs/xfs/xfs_bmap.c
===================================================================
--- xfs.orig/fs/xfs/xfs_bmap.c  2011-05-11 10:16:58.847733078 +0200
+++ xfs/fs/xfs/xfs_bmap.c       2011-05-11 10:17:04.803235692 +0200
@@ -5145,9 +5145,12 @@ xfs_bunmapi(
                                 */
                                ASSERT(bno >= del.br_blockcount);
                                bno -= del.br_blockcount;
-                               if (bno < got.br_startoff) {
-                                       if (--lastx >= 0)
-                                               xfs_bmbt_get_all(--ep, &got);
+                               if (got.br_startoff > bno) {
+                                       if (--lastx >= 0) {
+                                               ep = xfs_iext_get_ext(ifp,
+                                                                     lastx);
+                                               xfs_bmbt_get_all(ep, &got);
+                                       }
                                }
                                continue;
                        } else if (del.br_state == XFS_EXT_UNWRITTEN) {