f2fs: check inline_data flag at converting time

We can check inode's inline_data flag  when calling to convert it.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index bda7126..8090854 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -177,6 +177,9 @@
 	struct page *ipage, *page;
 	int err = 0;
 
+	if (!f2fs_has_inline_data(inode))
+		return 0;
+
 	page = grab_cache_page(inode->i_mapping, 0);
 	if (!page)
 		return -ENOMEM;