f2fs: fix return value of releasepage for node and data

If the return value of releasepage is equal to zero, the page cannot be reclaimed.
Instead, we should return 1 in order to reclaim clean pages.
Reviewed-by: NNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/data.c

@@ -683,7 +683,7 @@ static void f2fs_invalidate_data_page(struct page *page, unsigned long offset)
 static int f2fs_release_data_page(struct page *page, gfp_t wait)
 {
 	ClearPagePrivate(page);
-	return 0;
+	return 1;
 }
 
 static int f2fs_set_data_page_dirty(struct page *page)

fs/f2fs/node.c

@@ -933,7 +933,6 @@ struct page *get_node_page_ra(struct page *parent, int start)
 	if (!nid)
 		return ERR_PTR(-ENOENT);
 
-repeat:
 	page = grab_cache_page(mapping, nid);
 	if (!page)
 		return ERR_PTR(-ENOMEM);
@@ -961,12 +960,6 @@ struct page *get_node_page_ra(struct page *parent, int start)
 		f2fs_put_page(page, 1);
 		return ERR_PTR(-EIO);
 	}
-
-	/* Has the page been truncated? */
-	if (page->mapping != mapping) {
-		f2fs_put_page(page, 1);
-		goto repeat;
-	}
 	mark_page_accessed(page);
 	return page;
 }
@@ -1189,7 +1182,7 @@ static void f2fs_invalidate_node_page(struct page *page, unsigned long offset)
 static int f2fs_release_node_page(struct page *page, gfp_t wait)
 {
 	ClearPagePrivate(page);
-	return 0;
+	return 1;
 }
 
 /*
@@ -1630,8 +1623,6 @@ void flush_nat_entries(struct f2fs_sb_info *sbi)
 			write_lock(&nm_i->nat_tree_lock);
 			__del_from_nat_cache(nm_i, ne);
 			write_unlock(&nm_i->nat_tree_lock);
-
-			/* We can reuse this freed nid at this point */
 			add_free_nid(NM_I(sbi), nid);
 		} else {
 			write_lock(&nm_i->nat_tree_lock);