[PATCH 5/9] xfs: do not use unchecked extent indices in xfs_bmapi

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

Make sure to only call xfs_iext_get_ext after we've validate the extent index
when moving on to the next index in xfs_bmapi.

Based on an earlier patch from Lachlan McIlroy.

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

Index: xfs/fs/xfs/xfs_bmap.c
===================================================================
--- xfs.orig/fs/xfs/xfs_bmap.c  2011-05-11 10:16:58.831733512 +0200
+++ xfs/fs/xfs/xfs_bmap.c       2011-05-11 10:16:58.847733078 +0200
@@ -4827,12 +4827,13 @@ xfs_bmapi(
                /*
                 * Else go on to the next record.
                 */
-               ep = xfs_iext_get_ext(ifp, ++lastx);
                prev = got;
-               if (lastx >= nextents)
-                       eof = 1;
-               else
+               if (++lastx < nextents) {
+                       ep = xfs_iext_get_ext(ifp, lastx);
                        xfs_bmbt_get_all(ep, &got);
+               } else {
+                       eof = 1;
+               }
        }
        *nmap = n;
        /*