Btrfs: Add back file data checksumming

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 2a8bc4b..e87e476 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -2031,6 +2031,7 @@
 		i = 1;
 		index++;
 		page_cache_get(page0);
+		mark_page_accessed(page0);
 		set_page_extent_mapped(page0);
 		set_page_private(page0, EXTENT_PAGE_PRIVATE_FIRST_PAGE |
 				 len << 2);
@@ -2049,6 +2050,7 @@
 			goto fail;
 		}
 		set_page_extent_mapped(p);
+		mark_page_accessed(p);
 		if (i == 0) {
 			eb->first_page = p;
 			set_page_private(p, EXTENT_PAGE_PRIVATE_FIRST_PAGE |
@@ -2099,6 +2101,7 @@
 			goto fail;
 		}
 		set_page_extent_mapped(p);
+		mark_page_accessed(p);
 
 		if (i == 0) {
 			eb->first_page = p;