JFFS2: Fix oops in read_inode.

If the node with lowest version in a file was in the range
0xfffff000 onwards, we oopsed because our rounding was bogus.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

fs/jffs2/readinode.c

@@ -7,7 +7,7 @@
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
- * $Id: readinode.c,v 1.116 2004/11/16 20:36:12 dwmw2 Exp $
+ * $Id: readinode.c,v 1.117 2004/11/20 18:06:54 dwmw2 Exp $
  *
  */
 
@@ -227,7 +227,7 @@ static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *l
 		   If so, both 'this' and the new node get marked REF_NORMAL so
 		   the GC can take a look.
 		*/
-		if ((lastend-1) >> PAGE_CACHE_SHIFT == newfrag->ofs >> PAGE_CACHE_SHIFT) {
+		if (lastend && (lastend-1) >> PAGE_CACHE_SHIFT == newfrag->ofs >> PAGE_CACHE_SHIFT) {
 			if (this->node)
 				mark_ref_normal(this->node->raw);
 			mark_ref_normal(newfrag->node->raw);