f2fs: clear page's up-to-date if block was deallocated

If page's on-disk block was deallocated, let's remove up-to-date flag to avoid
further access with wrong contents.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 2842369..35a9117 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1002,6 +1002,7 @@
 	get_node_info(sbi, page->index, &ni);
 
 	if (unlikely(ni.blk_addr == NULL_ADDR)) {
+		ClearPageUptodate(page);
 		f2fs_put_page(page, 1);
 		return -ENOENT;
 	}
@@ -1313,6 +1314,7 @@
 
 	/* This page is already truncated */
 	if (unlikely(ni.blk_addr == NULL_ADDR)) {
+		ClearPageUptodate(page);
 		dec_page_count(sbi, F2FS_DIRTY_NODES);
 		unlock_page(page);
 		return 0;